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Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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1

CX-008498: Categorical Exclusion Determination  

Energy.gov (U.S. Department of Energy (DOE))

Ultra-High Conductivity Umbilicals: Polymer Nanotube Umbilicals (PNUs) CX(s) Applied: A9, B3.6 Date: 07/18/2012 Location(s): Texas Offices(s): National Energy Technology Laboratory

2

CX-008497: Categorical Exclusion Determination  

Energy.gov (U.S. Department of Energy (DOE))

Ultra-High Conductivity Umbilicals: Polymer Nanotube Umbilicals (PNUs) CX(s) Applied: A9, A11, B3.6 Date: 07/18/2012 Location(s): Texas Offices(s): National Energy Technology Laboratory

3

Magnetic nanotubes  

DOE Patents (OSTI)

A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.

Matsui, Hiroshi (Glen Rock, NJ); Matsunaga, Tadashi (Tokyo, JP)

2010-11-16T23:59:59.000Z

4

Nanotube Metrology  

Science Conference Proceedings (OSTI)

... for, and fundamental understanding of, single-wall carbon nanotubes (SWCNTs). ... We recently held a workshop to capture advancing measurement ...

2013-04-05T23:59:59.000Z

5

Nanotube junctions  

DOE Patents (OSTI)

The present invention comprises a new nanoscale metal-semiconductor, semiconductor-semiconductor, or metal-metal junction, designed by introducing topological or chemical defects in the atomic structure of the nanotube. Nanotubes comprising adjacent sections having differing electrical properties are described. These nanotubes can be constructed from combinations of carbon, boron, nitrogen and other elements. The nanotube can be designed having different indices on either side of a junction point in a continuous tube so that the electrical properties on either side of the junction vary in a useful fashion. For example, the inventive nanotube may be electrically conducting on one side of a junction and semiconducting on the other side. An example of a semiconductor-metal junction is a Schottky barrier. Alternatively, the nanotube may exhibit different semiconductor properties on either side of the junction. Nanotubes containing heterojunctions, Schottky barriers, and metal-metal junctions are useful for microcircuitry.

Crespi, Vincent Henry (Darien, IL); Cohen, Marvin Lou (Berkeley, CA); Louie, Steven Gwon Sheng (Berkeley, CA); Zettl, Alexander Karlwalter (Kensington, CA)

2003-01-01T23:59:59.000Z

6

Phase I Final Technical Report  

NLE Websites -- All DOE Office Websites (Extended Search)

Final Report to Final Report to Phase I Final Technical Report 10121.4302.01.Final1 Ultra-High Conductivity Umbilicals: Polymer Nanotube Umbilicals (PNUs) 10121-4302-01 June 24, 2013 Christopher A. Dyke Principal Investigator NanoRidge Materials, Inc. 15850 Vickery Drive Houston, Texas 77032 LEGAL NOTICE THIS REPORT WAS PREPARED BY NANORIDGE MATERIALS, INC. AS AN ACCOUNT OF WORK SPONSORED BY THE RESEARCH PARTNERSHIP TO SECURE ENERGY FOR AMERICA, RPSEA. NEITHER RPSEA MEMBERS OF RPSEA, THE NATIONAL ENERGY TECHNOLOGY LABORATORY, THE U.S. DEPARTMENT OF ENERGY, NOR ANY PERSON ACTING ON BEHALF OF ANY OF THE ENTITIES: a. MAKES ANY WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED WITH RESPECT TO ACCURACY, COMPLETENESS, OR USEFULNESS OF THE INFORMATION

7

Page not found | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

31 - 13340 of 26,764 results. 31 - 13340 of 26,764 results. Download CX-008495: Categorical Exclusion Determination Utility Metering Installation For: Buildings 2, 4, 5, 13, 17, 29, 33 CX(s) Applied: B2.2 Date: 07/23/2012 Location(s): West Virginia Offices(s): National Energy Technology Laboratory http://energy.gov/nepa/downloads/cx-008495-categorical-exclusion-determination Download CX-008496: Categorical Exclusion Determination Interstate Electrification Improvement CX(s) Applied: B5.1 Date: 07/23/2012 Location(s): Wyoming Offices(s): National Energy Technology Laboratory http://energy.gov/nepa/downloads/cx-008496-categorical-exclusion-determination Download CX-008497: Categorical Exclusion Determination Ultra-High Conductivity Umbilicals: Polymer Nanotube Umbilicals (PNUs) CX(s) Applied: A9, A11, B3.6

8

Nanotube Heterojunctions  

Nano- & Micro-technology; Software and IT ; Licensing Interest Form Receive Customized Tech Alerts. Nanotube Heterojunctions IB-1181. APPLICATIONS OF TECHNOLOGY:

9

Carbon Nanotubes  

Science Conference Proceedings (OSTI)

Carbon Nanotubes. Sponsored by: TMS Electronic, Magnetic and Photonic Materials Division Date and Time: Sunday, February 13, 2005 ~ 8:30 am-5:00 pm

10

Heteroporphyrin nanotubes and composites  

DOE Patents (OSTI)

Heteroporphyrin nanotubes, metal nanostructures, and metal/porphyrin-nanotube composite nanostructures formed using the nanotubes as photocatalysts and structural templates, and the methods for forming the nanotubes and composites.

Shelnutt, John A. (Tijeras, NM); Medforth, Craig J. (Winters, CA); Wang, Zhongchun (Albuquerque, NM)

2007-05-29T23:59:59.000Z

11

Photophysics of carbon nanotubes  

E-Print Network (OSTI)

This thesis reviews the recent advances made in optical studies of single-wall carbon nanotubes. Studying the electronic and vibrational properties of carbon nanotubes, we find that carbon nanotubes less than 1 nm in ...

Samsonidze, Georgii G

2007-01-01T23:59:59.000Z

12

Carbon Nanotubes Information at NIST  

Science Conference Proceedings (OSTI)

... John Bonevich. Laser Applications Heat Up for Carbon Nanotubes. Longer is Better for Nanotube Optical Properties. Modeling ...

2010-10-05T23:59:59.000Z

13

4th Carbon Nanotube Workshop  

Science Conference Proceedings (OSTI)

... measurments, and disseinate this summary to the nanotube community. ... RM) for length separated single-wall carbon nanotubes in aqueous ...

2013-04-05T23:59:59.000Z

14

Carbon nanotube nanoelectrode arrays  

DOE Patents (OSTI)

The present invention relates to microelectode arrays (MEAs), and more particularly to carbon nanotube nanoelectrode arrays (CNT-NEAs) for chemical and biological sensing, and methods of use. A nanoelectrode array includes a carbon nanotube material comprising an array of substantially linear carbon nanotubes each having a proximal end and a distal end, the proximal end of the carbon nanotubes are attached to a catalyst substrate material so as to form the array with a pre-determined site density, wherein the carbon nanotubes are aligned with respect to one another within the array; an electrically insulating layer on the surface of the carbon nanotube material, whereby the distal end of the carbon nanotubes extend beyond the electrically insulating layer; a second adhesive electrically insulating layer on the surface of the electrically insulating layer, whereby the distal end of the carbon nanotubes extend beyond the second adhesive electrically insulating layer; and a metal wire attached to the catalyst substrate material.

Ren, Zhifeng (Newton, MA); Lin, Yuehe (Richland, WA); Yantasee, Wassana (Richland, WA); Liu, Guodong (Fargo, ND); Lu, Fang (Burlingame, CA); Tu, Yi (Camarillo, CA)

2008-11-18T23:59:59.000Z

15

Electron Microscopy of Carbon Nanotube Composites  

Science Conference Proceedings (OSTI)

Electron Microscopy of Carbon Nanotube Composites. Summary: Carbon nanomaterials such as carbon nanotubes (CNTs ...

2013-07-01T23:59:59.000Z

16

Nanotube Quality Control  

Science Conference Proceedings (OSTI)

... A variety of coating techniques can be used to deposit the nanotube material, including drop casting, spin coating, and spray deposition. ...

2012-11-13T23:59:59.000Z

17

Reinforced Carbon Nanotubes.  

DOE Patents (OSTI)

The present invention relates generally to reinforced carbon nanotubes, and more particularly to reinforced carbon nanotubes having a plurality of microparticulate carbide or oxide materials formed substantially on the surface of such reinforced carbon nanotubes composite materials. In particular, the present invention provides reinforced carbon nanotubes (CNTs) having a plurality of boron carbide nanolumps formed substantially on a surface of the reinforced CNTs that provide a reinforcing effect on CNTs, enabling their use as effective reinforcing fillers for matrix materials to give high-strength composites. The present invention also provides methods for producing such carbide reinforced CNTs.

Ren, Zhifen (Newton, MA); Wen, Jian Guo (Newton, MA); Lao, Jing Y. (Chestnut Hill, MA); Li, Wenzhi (Brookline, MA)

2005-06-28T23:59:59.000Z

18

New Nanotube Coating Enables Novel Laser Power Meter  

Science Conference Proceedings (OSTI)

... found that multiwalled carbon nanotubes perform better than single-walled nanotubes. Researchers are continuing to seek nanotube formulas that ...

2013-03-18T23:59:59.000Z

19

Fluidic nanotubes and devices  

DOE Patents (OSTI)

Fluidic nanotube devices are described in which a hydrophilic, non-carbon nanotube, has its ends fluidly coupled to reservoirs. Source and drain contacts are connected to opposing ends of the nanotube, or within each reservoir near the opening of the nanotube. The passage of molecular species can be sensed by measuring current flow (source-drain, ionic, or combination). The tube interior can be functionalized by joining binding molecules so that different molecular species can be sensed by detecting current changes. The nanotube may be a semiconductor, wherein a tubular transistor is formed. A gate electrode can be attached between source and drain to control current flow and ionic flow. By way of example an electrophoretic array embodiment is described, integrating MEMs switches. A variety of applications are described, such as: nanopores, nanocapillary devices, nanoelectrophoretic, DNA sequence detectors, immunosensors, thermoelectric devices, photonic devices, nanoscale fluidic bioseparators, imaging devices, and so forth.

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

2010-01-10T23:59:59.000Z

20

Fluidic nanotubes and devices  

DOE Patents (OSTI)

Fluidic nanotube devices are described in which a hydrophilic, non-carbon nanotube, has its ends fluidly coupled to reservoirs. Source and drain contacts are connected to opposing ends of the nanotube, or within each reservoir near the opening of the nanotube. The passage of molecular species can be sensed by measuring current flow (source-drain, ionic, or combination). The tube interior can be functionalized by joining binding molecules so that different molecular species can be sensed by detecting current changes. The nanotube may be a semiconductor, wherein a tubular transistor is formed. A gate electrode can be attached between source and drain to control current flow and ionic flow. By way of example an electrophoretic array embodiment is described, integrating MEMs switches. A variety of applications are described, such as: nanopores, nanocapillary devices, nanoelectrophoretic, DNA sequence detectors, immunosensors, thermoelectric devices, photonic devices, nanoscale fluidic bioseparators, imaging devices, and so forth.

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

2008-04-08T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Vertically Aligned and Periodically Distributed Carbon Nanotube  

Science Conference Proceedings (OSTI)

Presentation Title, Vertically Aligned and Periodically Distributed Carbon Nanotube (CNT) ... Application of Carbon Nanotubes – Energy to Bioelectronic Sensor.

22

DIRECT OBSERVATION OF CARBON NANOTUBE GROWTH ...  

Science Conference Proceedings (OSTI)

... Carbon nanotubes (CNTs) provide two particularly exciting prospects. ... particular, the relationship between the nucleating/growing nanotube and the ...

23

Carbon nanotube zoom lenses  

Science Conference Proceedings (OSTI)

We show that convergent or divergent zoom lenses with focal length variations up to approximately 100% can be implemented by growing arrays of carbon nanotubes (CNTs) on curved templates. Unique lenses, which can change their character from divergent ...

D. Dragoman; M. Dragoman

2003-06-01T23:59:59.000Z

24

Boron nitride nanotubes  

Science Conference Proceedings (OSTI)

Boron nitride nanotubes are prepared by a process which includes: (a) creating a source of boron vapor; (b) mixing the boron vapor with nitrogen gas so that a mixture of boron vapor and nitrogen gas is present at a nucleation site, which is a surface, the nitrogen gas being provided at a pressure elevated above atmospheric, e.g., from greater than about 2 atmospheres up to about 250 atmospheres; and (c) harvesting boron nitride nanotubes, which are formed at the nucleation site.

Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA); Park, Cheol (Yorktown, VA)

2012-06-06T23:59:59.000Z

25

Sensor applications of carbon nanotubes  

E-Print Network (OSTI)

A search of published research on sensing mechanisms of carbon nanotubes was performed to identify applications in which carbon nanotubes might improve on current sensor technologies, in either offering improved performance, ...

Rushfeldt, Scott I

2005-01-01T23:59:59.000Z

26

Carbon nanotubes on a substrate  

DOE Patents (OSTI)

The present invention includes carbon nanotubes whose hollow cores are 100% filled with conductive filler. The carbon nanotubes are in uniform arrays on a conductive substrate and are well-aligned and can be densely packed. The uniformity of the carbon nanotube arrays is indicated by the uniform length and diameter of the carbon nanotubes, both which vary from nanotube to nanotube on a given array by no more than about 5%. The alignment of the carbon nanotubes is indicated by the perpendicular growth of the nanotubes from the substrates which is achieved in part by the simultaneous growth of the conductive filler within the hollow core of the nanotube and the densely packed growth of the nanotubes. The present invention provides a densely packed carbon nanotube growth where each nanotube is in contact with at least one nearest-neighbor nanotube. The substrate is a conductive substrate coated with a growth catalyst, and the conductive filler can be single crystals of carbide formed by a solid state reaction between the substrate material and the growth catalyst. The present invention further provides a method for making the filled carbon nanotubes on the conductive substrates. The method includes the steps of depositing a growth catalyst onto the conductive substrate as a prepared substrate, creating a vacuum within a vessel which contains the prepared substrate, flowing H2/inert (e.g. Ar) gas within the vessel to increase and maintain the pressure within the vessel, increasing the temperature of the prepared substrate, and changing the H2/Ar gas to ethylene gas such that the ethylene gas flows within the vessel. Additionally, varying the density and separation of the catalyst particles on the conductive substrate can be used to control the diameter of the nanotubes.

Gao, Yufei [Kennewick, WA; Liu, Jun [West Richland, WA

2002-03-26T23:59:59.000Z

27

Carbon Nanotube and Graphene Nanoelectromechanical Systems  

E-Print Network (OSTI)

2 Electromechanics of Carbon Nanotube Resonators 2.1 Basic3.4.2 Capacitance of a Carbon Nanotube Field-Emission Tunnel5 Parametric Ampli?cation in Carbon Nanotube Resonators 5.1

Aleman, Benjamin Jose

2011-01-01T23:59:59.000Z

28

Carbon nanotubes : synthesis, characterization, and applications  

E-Print Network (OSTI)

around Surface-Attached Carbon Nanotubes. Ind. Eng. Chem.the flexural rigidity of carbon nanotube ensembles. AppliedNanotechnology in Carbon Materials. Acta Metallurgica, 1997.

Deck, Christian Peter

2009-01-01T23:59:59.000Z

29

Carbon Nanotubes Make Simultaneous Temperature, Pressure ...  

ORNL 2010-G00384/jcn UT-B ID 200702020 Carbon Nanotubes Make Simultaneous Temperature, Pressure Sensors Possible Technology Summary Carbon nanotubes ...

30

Can Nanotubes Be Engineered to Superconduct? Study ...  

Science Conference Proceedings (OSTI)

... walled carbon nanotubes can be controlled through a reversible process called mechanical deformation. Flattening the radius of a nanotube so that ...

2012-12-13T23:59:59.000Z

31

Combining Nanotubes and Antibodies for Breast Cancer ' ...  

Science Conference Proceedings (OSTI)

... of the special combination—the antibody and the nanotube—have critical ... The carbon nanotubes attached to the antibodies also become linked to ...

2012-10-15T23:59:59.000Z

32

Carbon NanoTube Digital Electronics Workshop  

Science Conference Proceedings (OSTI)

Carbon NanoTube Digital Electronics Workshop. Purpose: To review and discuss the current status and potential benefits of carbon nanotubes in ...

2012-08-29T23:59:59.000Z

33

Stable Polymer Nanotubes May Have a Biotech Future  

Science Conference Proceedings (OSTI)

... one at a time.Carbon nanotubes are of ... the shelf life of polymer nanotubes— considered essential ... and forming sturdy nanotube network structures. ...

2013-08-07T23:59:59.000Z

34

Carbon nanotube IR detectors (SV)  

SciTech Connect

Sandia National Laboratories (Sandia) and Lockheed Martin Corporation (LMC) collaborated to (1) evaluate the potential of carbon nanotubes as channels in infrared (IR) photodetectors; (2) assemble and characterize carbon nanotube electronic devices and measure the photocurrent generated when exposed to infrared light;(3) compare the performance of the carbon nanotube devices with that of traditional devices; and (4) develop and numerically implement models of electronic transport and opto-electronic behavior of carbon nanotube infrared detectors. This work established a new paradigm for photodetectors.

Leonard, F. L.

2012-03-01T23:59:59.000Z

35

Hydrogen Storage in Carbon Nanotubes  

NLE Websites -- All DOE Office Websites (Extended Search)

STORAGE IN CARBON NANOTUBES JOHN E. FISCHER UNIVERSITY OF PENNSYLVANIA * SOME BASIC NOTIONS * BINDING SITES AND ENERGIES * PROCESSING TO ENHANCE CAPACITY: EX: ELECTROCHEMICAL Li...

36

Carbon nanotube-polymer composite actuators  

DOE Patents (OSTI)

The present invention discloses a carbon nanotube (SWNT)-polymer composite actuator and method to make such actuator. A series of uniform composites was prepared by dispersing purified single wall nanotubes with varying weight percents into a polymer matrix, followed by solution casting. The resulting nanotube-polymer composite was then successfully used to form a nanotube polymer actuator.

Gennett, Thomas (Denver, CO); Raffaelle, Ryne P. (Honeoye Falls, NY); Landi, Brian J. (Rochester, NY); Heben, Michael J. (Denver, CO)

2008-04-22T23:59:59.000Z

37

Carbon Nanotube Measurements: Latest in NIST 'How-To' ...  

Science Conference Proceedings (OSTI)

... devoted to nanotube measurements. The NIST “Recommended Practice Guide” on Measurement Issues in Single Wall Carbon Nanotubes grew ...

2012-10-17T23:59:59.000Z

38

Emerging Applications of Carbon Nanotubes  

E-Print Network (OSTI)

On the basis of their unique electrical and mechanical properties, carbon nanotubes (CNTs) have attracted great attention in recent years. A diverse array of methods has been developed to modify CNTs and to assemble them ...

Schnorr, Jan Markus

39

Method for producing carbon nanotubes  

DOE Patents (OSTI)

Method for producing carbon nanotubes. Carbon nanotubes were prepared using a low power, atmospheric pressure, microwave-generated plasma torch system. After generating carbon monoxide microwave plasma, a flow of carbon monoxide was directed first through a bed of metal particles/glass beads and then along the outer surface of a ceramic tube located in the plasma. As a flow of argon was introduced into the plasma through the ceramic tube, ropes of entangled carbon nanotubes, attached to the surface of the tube, were produced. Of these, longer ropes formed on the surface portion of the tube located in the center of the plasma. Transmission electron micrographs of individual nanotubes revealed that many were single-walled.

Phillips, Jonathan (Santa Fe, NM); Perry, William L. (Jemez Springs, NM); Chen, Chun-Ku (Albuquerque, NM)

2006-02-14T23:59:59.000Z

40

Mechanical energy storage in carbon nanotube springs  

E-Print Network (OSTI)

Energy storage in mechanical springs made of carbon nanotubes is a promising new technology. Springs made of dense, ordered arrays of carbon nanotubes have the potential to surpass both the energy density of electrochemical ...

Hill, Frances Ann

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

A carbon nanotube bearing and Stodola rotor  

E-Print Network (OSTI)

A nano-scale rotor supported on a cantilevered multi-wall carbon nanotube (MWNT) shaft (Stodola configuration) is proposed. The nanotube is also expected to function as the bearing, since individual walls of a MWNT are not ...

Cook, Eugene Hightower

2008-01-01T23:59:59.000Z

42

Carbon Nanotube Nanocomposites, Methods of Making Carbon ...  

This technology describes methods to fabricate supercapacitors using aligned carbon nanotubes that are decorated with metal oxide or nitride ...

43

Fatigue Resistance of Carbon Nanotube Reinforced Aluminum ...  

Science Conference Proceedings (OSTI)

Presentation Title, Fatigue Resistance of Carbon Nanotube Reinforced Aluminum ... Fatigue crack propagation (FCP) and fracture mechanism of Al-CNT  ...

44

Hallosite Clay Nanotubes as “Green” Nanocontainers for ...  

Science Conference Proceedings (OSTI)

Symposium, Advanced Coatings and Surface Treatments for Corrosion Protection. Presentation Title, Hallosite Clay Nanotubes as “Green” Nanocontainers for ...

45

Carbon Nanotube Reinforced Pure Titanium Powder Composite ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2010. Symposium, Nanotube Reinforced Metal Matrix Composites II. Presentation Title, Carbon ...

46

Molecular jet growth of carbon nanotubes and dense vertically aligned nanotube arrays  

DOE Patents (OSTI)

A method of growing a carbon nanotube includes the step of impinging a beam of carbon-containing molecules onto a substrate to grow at least one carbon nanotube on the catalyst surface.

Eres, Gyula (Knoxville, TN)

2010-10-12T23:59:59.000Z

47

Carbon Nanotube Arrays: Synthesis of Dense Arrays of Well ...  

Carbon Nanotube Arrays: Synthesis of Dense Arrays of Well-Aligned Carbon Nanotubes Completely Filled with Titanium Carbide on Titanium Substrates

48

3D Carbon Nanotube based Photovoltaic Devices - Programmaster ...  

Science Conference Proceedings (OSTI)

We introduce a three dimensional photovoltaic device with carbon nanotube pillars ... The extra dimensionality of this cell added by the nanotubes has been ...

49

Tuning the Properties of Carbon Nanotubes by Deformation  

Science Conference Proceedings (OSTI)

... for metal coverage and for selective adsorption and desorption of atoms and molecules on carbon nanotubes. ... nist . gov/staff/taner/nanotube. ...

50

NIST Study Suggests Carbon Nanotubes May Protect DNA ...  

Science Conference Proceedings (OSTI)

... wall carbon nanotube soot standard reference material. Recent NIST research suggests that, at least in the laboratory, carbon nanotubes may help ...

2012-11-14T23:59:59.000Z

51

Super-Nanotubes: 'Remarkable' Spray-on Coating Combines ...  

Science Conference Proceedings (OSTI)

... have demonstrated a spray-on mixture of carbon nanotubes and ceramic ... of one strand of a new spray-on super-nanotube composite developed by ...

2013-04-17T23:59:59.000Z

52

Quantum transport and field-induced superconductivity in carbon nanotubes.  

E-Print Network (OSTI)

?? For my thesis, I conducted experiments to investigate superconductivity and superconducting proximity effect in carbon nanotubes. The measurements are carried out on carbon nanotube… (more)

Yang, Yanfei

2010-01-01T23:59:59.000Z

53

Multiscale modeling with carbon nanotubes  

Science Conference Proceedings (OSTI)

Technologically important nanomaterials come in all shapes and sizes. They can range from small molecules to complex composites and mixtures. Depending upon the spatial dimensions of the system and properties under investigation computer modeling of ... Keywords: DFT (density functional theory), Mesoscale modeling, Molecular modeling, NEGF (nonequilibrium Green's function), NEMS (nanoelectromechanical sensors), Nanocomposites, Nanotubes, Sensors

Amitesh Maiti

2008-02-01T23:59:59.000Z

54

Method for synthesizing carbon nanotubes  

Science Conference Proceedings (OSTI)

A method for preparing a precursor solution for synthesis of carbon nanomaterials, where a polar solvent is added to at least one block copolymer and at least one carbohydrate compound, and the precursor solution is processed using a self-assembly process and subsequent heating to form nanoporous carbon films, porous carbon nanotubes, and porous carbon nanoparticles.

Fan, Hongyou

2012-09-04T23:59:59.000Z

55

Ultrahig h F requency Nanotube Resonators  

A new combination of drive and detection methods ... mobility of static charges near the nanotube. The resonator serv es as an exceptionally sensiti ...

56

Nanotube Reinforced Metal Matrix Composites II  

Science Conference Proceedings (OSTI)

Symposium, Nanotube Reinforced Metal Matrix Composites II. Sponsorship, MS&T Organization. Organizer(s), Indrajit Charit, University of Idaho Sudipta Seal  ...

57

BSA 07-30: Functionalized Carbon Nanotubes  

BSA 07-30: Functionalized Carbon Nanotubes. BNL Reference Number: BSA 07-30. Patent Status: Application Number 20090308753 was published on December ...

58

Thermal Management Using Carbon Nanotubes - Energy Innovation ...  

Patent 7,763,353: Fabrication of high thermal conductivity arrays of carbon nanotubes and their composites Methods and apparatus are described for ...

59

Harnessing the Wind with Carbon Nanotubes  

Science Conference Proceedings (OSTI)

Aug 7, 2009 ... The overall goal of the project, “Carbon Nanotube Reinforced Polyurethane Composites for Wind Turbine Blades,” is to help accelerate ...

60

Available Technologies: Synthesizing Boron Nitride Nanotubes and ...  

Nano- & Micro-technology; Software and IT ; Licensing Interest Form Receive Customized Tech Alerts. Synthesizing Boron Nitride Nanotubes and Related Nanoparticles

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Raman spectroscopy of metallic carbon nanotubes  

E-Print Network (OSTI)

Metallic carbon nanotubes are one dimensional conductors that are both technologically promising for electronic applications, and scientifically interesting for studying the physics of low dimensional materials. In this ...

Farhat, Hootan

2010-01-01T23:59:59.000Z

62

Session U: Graphene and Nanotubes - Devices  

Science Conference Proceedings (OSTI)

Jun 24, 2010 ... But the resistance of carbon nanotube devices is not a simple function of the length, and the output swing of saturated-load inverters is ...

63

Carbon Nanotube Nano-Electrode Arrays - Available ...  

Computers & Electronics; Publication(s) Nanoelectrode Arrays Based on Low Site Density Aligned Carbon Nanotubes. (pdf) - Tu, Y., Lin, Y., Ren, ...

64

Carbon Nanotube GHz Nano-Resonator Shengdong Li1  

E-Print Network (OSTI)

Carbon Nanotube GHz Nano-Resonator Shengdong Li1 , Zhen Yu1 , Sheng-Feng Yen1 , Peter J. Burke1 walled carbon nanotube. Both semiconducting and metallic nanotubes are measured. Using a semiconducting signal processing components based on carbon nanotubes. Index Terms -- Nanotechnology, Resonators, Tuning

Tang, William C

65

Geometric polyhedral models for nanotubes comprising hexagonal lattices  

Science Conference Proceedings (OSTI)

Two new models for the geometric structure of nanotubes comprising hexagonal lattices are described. The existing models for nanotubes typically involve rolled up planar sheets and ignore discrepancies due to curvature. The first of the models presented ... Keywords: Boron nitride nanotubes, Carbon nanotubes, Continuum models, Geometric models, Wall thickness

Barry J. Cox; James M. Hill

2011-05-01T23:59:59.000Z

66

Oriented nanotube electrodes for lithium ion batteries and supercapacitors  

DOE Patents (OSTI)

An electrode having an oriented array of multiple nanotubes is disclosed. Individual nanotubes have a lengthwise inner pore defined by interior tube walls which extends at least partially through the length of the nanotube. The nanotubes of the array may be oriented according to any identifiable pattern. Also disclosed is a device featuring an electrode and methods of fabrication.

Frank, Arthur J.; Zhu, Kai; Wang, Qing

2013-03-05T23:59:59.000Z

67

Method for nano-pumping using carbon nanotubes  

DOE Patents (OSTI)

The present invention relates generally to the field of nanotechnology, carbon nanotubes and, more specifically, to a method and system for nano-pumping media through carbon nanotubes. One preferred embodiment of the invention generally comprises: method for nano-pumping, comprising the following steps: providing one or more media; providing one or more carbon nanotubes, the one or more nanotubes having a first end and a second end, wherein said first end of one or more nanotubes is in contact with the media; and creating surface waves on the carbon nanotubes, wherein at least a portion of the media is pumped through the nanotube.

Insepov, Zeke (Darien, IL); Hassanein, Ahmed (Bolingbrook, IL)

2009-12-15T23:59:59.000Z

68

Carbon nanotube composites P. J. F. Harris*  

E-Print Network (OSTI)

of matrix. A wide range of polymer matrices have been employed, and there is growing interest in nanotube/ceramic, as well as from industry, and nanotubes are currently the subject of around 7 papers per day, such as ceramics and metals. The ai

Harris, Peter J F

69

PLANAR MEMS SUPERCAPACITOR USING CARBON NANOTUBE FORESTS  

E-Print Network (OSTI)

PLANAR MEMS SUPERCAPACITOR USING CARBON NANOTUBE FORESTS Y.Q. Jiang, Q. Zhou, and L. Lin Mechanical ABSTRACT Planar micro supercapacitors utilizing vertically aligned carbon nanotube (CNT) forests and very robust cycling stability. As such, we believe these planar MEMS supercapacitors could

Lin, Liwei

70

Sacrificial template method of fabricating a nanotube  

DOE Patents (OSTI)

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 <001> 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.

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)

2007-05-01T23:59:59.000Z

71

Multi-wall carbon nanotubes in microwaves  

Science Conference Proceedings (OSTI)

The electromagnetic (EM) response of multi-wall carbon nanotubes (MWCNT) prepared by chemical vapor decomposition (CVD) method has been analyzed in the microwave frequency range. EM absorption properties of MWCNT depend on their medium diameter related ... Keywords: carbon nanotube, coating, electromagnetic absorption, microwave

S. Moseenkov; V. Kuznetsov; A. Usoltseva; I. Mazov; A. Ischenko; T. Buryakov; O. Anikeeva; A. Romanenko; P. Kuzhir; D. Bychenok; K. Batrakov; S. Maksimenko

2009-02-01T23:59:59.000Z

72

Irradiation Stability of Carbon Nanotubes  

E-Print Network (OSTI)

Ion irradiation of carbon nanotubes is a tool that can be used to achieve modification of the structure. Irradiation stability of carbon nanotubes was studied by ion and electron bombardment of the samples. Different ion species at various energies were used in experiments, and several defect characterization techniques were applied to characterize the damage. Development of dimensional changes of carbon nanotubes in microscopes operated at accelerating voltages of 30 keV revealed that binding energy of carbon atoms in CNs is much lower than in bulk materials. Resistivity measurements during irradiation demonstrated existence of a quasi state of defect creation. Linear relationship between ID/IG ratio and increasing irradiation fluence was revealed by Raman spectroscopy study of irradiated carbon buckypapers. The deviations from linear relationship were observed for the samples irradiated to very high fluence values. Annealing of irradiated samples was able to reduce the value of ID/IG ratio and remove defects. However, annealing could not affect ID/IG ratio and remove defects in amorphized samples. The extracted value of activation energy for irradiated sample was 0.36 ±0.05 eV. The value of activation energy was in good agreement with theoretical studies.

Aitkaliyeva, Assel

2009-08-01T23:59:59.000Z

73

CARBON NANOTUBES: PROPERTIES AND APPLICATIONS  

SciTech Connect

Carbon nanotubes were discovered in 1991 as a minority byproduct of fullerene synthesis. Remarkable progress has been made in the ensuing years, including the discovery of two basic types of nanotubes (single-wall and multi-wall), great strides in synthesis and purification, elucidation of many fundamental physical properties, and important steps towards practical applications. Both the underlying science and technological potential of SWNT can profitably be studied at the scale of individual tubes and on macroscopic assemblies such as fibers. Experiments on single tubes directly reveal many of the predicted quantum confinement and mechanical properties. Semiconductor nanowires have many features in common with nanotubes, and many of the same fundamental and practical issues are in play – quantum confinement and its effect on properties; possible device structures and circuit architectures; thermal management; optimal synthesis, defect morphology and control, etc. In 2000 we began a small effort in this direction, conducted entirely by undergraduates with minimal consumables support from this grant. With DOE-BES approval, this grew into a project in parallel with the carbon nanotube work, in which we studied of inorganic semiconductor nanowire growth, characterization and novel strategies for electronic and electromechanical device fabrication. From the beginnings of research on carbon nanotubes, one of the major applications envisioned was hydrogen storage for fuel-cell powered cars and trucks. Subsequent theoretical models gave mixed results, the most pessimistic indicating that the fundamental H2-SWNT interaction was similar to flat graphite (physisorption) with only modest binding energies implying cryogenic operation at best. New material families with encouraging measured properties have emerged, and materials modeling has gained enormously in predictive power, sophistication, and the ability to treat a realistically representative number of atoms. One of the new materials, highly porous carbide-derived carbons (CDC), is the subject of an add-on to this grant awarded to myself and Taner Yildirim (NIST). Results from the add-on led eventually to a new 3-year award DE-FG02-08ER46522 “From Fundamental Understanding to Predicting New Nanomaterials for High Capacity Hydrogen Storage”, $1000K, (05/31/2008 - 05/01/2011) with Taner Yildirim and myself as co-PI’s.

Fischer, John, E.

2009-07-24T23:59:59.000Z

74

Preparation of Carbon Nanotube-Composite  

E-Print Network (OSTI)

A composite is made up of two distinct materials and the resulted properties are different from the individual precursors. Composite combines a huge or bulkier element called matrix and reinforcement called filler or fiber. Fiber is added in the matrix to increase the stiffness of the matrix and enhance or alter its physical properties. Since silk has high levels of toughness, strength and multifunctional nature, we decided to use bombyx mori as a matrix. Because of the superior mechanical properties, i.e., high tensile moduli, and strength of carbon nanotube, we chose carbon nanotube as a reinforcement fiber to enhance the mechanical properties of resulting composite. The main issue encountered while preparing composite was to fully disperse individual nanotubes in the matrices, because nanotubes tend to form clusters and bundles. Hence, we used ionic liquids to dissolve the cocoon, and processed homogenization of FCNT with silk by sonication, stirring. For testing, different weight percentages of functionalized carbon nanotube were used as a filler to make the silk composite, and nanoindentation and tensile tester tested the samples. The composite of various concentrations did not show the expected result of increasing mechanical properties with decreased carbon nanotube concentration. Hence, it was concluded that a different method to functionalize carbon nanotube should be implemented.

Sharma, Sundeep

2011-05-01T23:59:59.000Z

75

Methods for producing reinforced carbon nanotubes  

DOE Patents (OSTI)

Methods for producing reinforced carbon nanotubes having a plurality of microparticulate carbide or oxide materials formed substantially on the surface of such reinforced carbon nanotubes composite materials are disclosed. In particular, the present invention provides reinforced carbon nanotubes (CNTs) having a plurality of boron carbide nanolumps formed substantially on a surface of the reinforced CNTs that provide a reinforcing effect on CNTs, enabling their use as effective reinforcing fillers for matrix materials to give high-strength composites. The present invention also provides methods for producing such carbide reinforced CNTs.

Ren, Zhifen (Newton, MA); Wen, Jian Guo (Newton, MA); Lao, Jing Y. (Chestnut Hill, MA); Li, Wenzhi (Brookline, MA)

2008-10-28T23:59:59.000Z

76

Carbon nanotube-based field ionization vacuum  

E-Print Network (OSTI)

We report the development of a novel micropump architecture that uses arrays of isolated vertical carbon nanotubes (CNT) to field ionize gas particles. The ionized gas molecules are accelerated to and implanted into a ...

Jang, Daniel, M. Eng. Massachusetts Institute of Technology

2012-01-01T23:59:59.000Z

77

Transplanting assembly of individual carbon nanotubes  

E-Print Network (OSTI)

Handling and assembling individual nanostructures to bigger scale systems such as MEMS have been the biggest challenge. A deterministic assembly of individual carbon nanotubes by transplanting them to MEMS structures is ...

Kim, Soohyung

2009-01-01T23:59:59.000Z

78

Functionalization and applications of carbon nanotubes  

E-Print Network (OSTI)

Carbon nanotubes (CNTs) possess a unique set of electrical and mechanical properties and have been used in a variety of applications. In this thesis, we explore strategies to functionalize CNTs as well as applications which ...

Schnorr, Jan M. (Jan Markus)

2012-01-01T23:59:59.000Z

79

Carbon nanotube polymer composition and devices  

DOE Patents (OSTI)

A thin film device and compound having an anode, a cathode, and at least one light emitting layer between the anode and cathode, the at least one light emitting layer having at least one carbon nanotube and a conductive polymer.

Liu, Gao (Oakland, CA); Johnson, Stephen (Richmond, CA); Kerr, John B. (Oakland, CA); Minor, Andrew M. (El Cerrito, CA); Mao, Samuel S. (Castro Valley, CA)

2011-06-14T23:59:59.000Z

80

Carbon nanotube synthesis for integrated circuit interconnects  

E-Print Network (OSTI)

Based on their properties, carbon nanotubes (CNTs) have been identified as ideal replacements for copper interconnects in integrated circuits given their higher current density, inertness, and higher resistance to ...

Nessim, Gilbert Daniel

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

BX CY NZ nanotubes and nanoparticles  

DOE Patents (OSTI)

The invention provides crystalline nanoscale particles and tubes made from a variety of stoichiometries of B.sub.x C.sub.y N.sub.z where x, y, and z indicate a relative amount of each element compared to the others and where no more than one of x, y, or z are zero for a single stoichiometry. The nanotubes and nanoparticles are useful as miniature electronic components, such as wires, coils, schotky barriers, diodes, etc. The nanotubes and nanoparticles are also useful as coating that will protect an item from detection by electromagnetic monitoring techniques like radar. The nanotubes and nanoparticles are additionally useful for their mechanical properties, being comparable in strength and stiffness to the best graphite fibers or carbon nanotubes. The inventive nanoparticles are useful in lubricants and composites.

Cohen, Marvin Lou (Piedmont, CA); Zettl, Alexander Karlwalter (Kensington, CA)

2001-01-01T23:59:59.000Z

82

Separation of carbon nanotubes in density gradients  

DOE Patents (OSTI)

The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

2012-02-07T23:59:59.000Z

83

Carbon nanotube heat-exchange systems  

DOE Patents (OSTI)

A carbon nanotube heat-exchange system (10) and method for producing the same. One embodiment of the carbon nanotube heat-exchange system (10) comprises a microchannel structure (24) having an inlet end (30) and an outlet end (32), the inlet end (30) providing a cooling fluid into the microchannel structure (24) and the outlet end (32) discharging the cooling fluid from the microchannel structure (24). At least one flow path (28) is defined in the microchannel structure (24), fluidically connecting the inlet end (30) to the outlet end (32) of the microchannel structure (24). A carbon nanotube structure (26) is provided in thermal contact with the microchannel structure (24), the carbon nanotube structure (26) receiving heat from the cooling fluid in the microchannel structure (24) and dissipating the heat into an external medium (19).

Hendricks, Terry Joseph (Arvada, CO); Heben, Michael J. (Denver, CO)

2008-11-11T23:59:59.000Z

84

Microbubble Generation Using Carbon Nanotubes Heating Elements  

Science Conference Proceedings (OSTI)

The generation of microbubbles using localized microwatt heating of carbon nanotubes (CNTs) is presented in this paper. Dielectrophoretic force is used to form CNTs between micrometal electrodes. The improvement for our CNTs heater is that a thin aligned ...

Peng Xiao; W. J. Li; Ruxu Du

2011-05-01T23:59:59.000Z

85

Separation of carbon nanotubes in density gradients  

DOE Patents (OSTI)

The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

2010-02-16T23:59:59.000Z

86

Fabrication of microscale carbon nanotube fibers  

Science Conference Proceedings (OSTI)

Carbon nanotubes (CNTs) have excellent mechanical, chemical, and electronic properties, but realizing these excellences in practical applications needs to assemble individual CNTs into larger-scale products. Recently, CNT fibers demonstrate the potential ...

Gengzhi Sun; Yani Zhang; Lianxi Zheng

2012-01-01T23:59:59.000Z

87

Carbon nanotube temperature and pressure sensors  

Science Conference Proceedings (OSTI)

The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

Ivanov, Ilia N; Geohegan, David Bruce

2013-10-29T23:59:59.000Z

88

Multiwalled carbon nanotubes decorated with cobalt oxide nanoparticles  

Science Conference Proceedings (OSTI)

Multiwalled carbon nanotubes (MWCNTs) synthesized by spray pyrolysis were decorated with cobalt oxide nanoparticles using a simple synthesis route. This wet chemistry method yielded nanoparticles randomly anchored to the surface of the nanotubes by decomposition ...

D. G. Larrude; P. Ayala; M. E. H. Maia da Costa; F. L. Freire

2012-01-01T23:59:59.000Z

89

Length dependence of the Raman spectra of carbon nanotubes  

E-Print Network (OSTI)

DNA-wrapping technology, combined with size-exclusion chromatography, have made possible the sorting of carbon nanotubes according to length. In particular, length sorted nanotube samples, with finite lengths approaching ...

Zare, Aurea Tucay

2009-01-01T23:59:59.000Z

90

Flame synthesis of carbon nanotubes and metallic nanomaterials  

E-Print Network (OSTI)

Carbon nanotubes are a remarkable material with many appealing properties. Despite the appeal of this material, there are few synthesis techniques capable of producing nanotubes in large quantities at low-cost. The broad ...

Height, Murray John, 1975-

2003-01-01T23:59:59.000Z

91

Optical and Thermal Characterization of Carbon Nanotube Film for ...  

Science Conference Proceedings (OSTI)

Symposium, Nanotechnology for Energy, Healthcare and Industry. Presentation Title, Optical and Thermal Characterization of Carbon Nanotube Film for Energy ...

92

Add Nanotubes and Stir—With the Right Force  

Science Conference Proceedings (OSTI)

... amount of force applied while mixing carbon nanotube suspensions influences the way the tiny cylinders ultimately disperse and orient themselves. ...

2012-10-18T23:59:59.000Z

93

Optimizing Carbon Nanotube Contacts for Use in Organic Photovoltaics: Preprint  

DOE Green Energy (OSTI)

This report describes research on optimizing carbon nanotube networks for use as transparent electrical contacts (TCs) in organic photovoltaics (OPV).

Barnes, T. M.; Blackburn, J. L.; Tenent, R. C.; Morfa, A.; Heben, M.; Coutts, T. J.

2008-05-01T23:59:59.000Z

94

Carbon Fibers and Carbon Nanotubes - Programmaster.org  

Science Conference Proceedings (OSTI)

Feb 17, 2010 ... Polymer Nanocomposites: Carbon Fibers and Carbon Nanotubes Sponsored by: The Minerals, Metals and Materials Society Program ...

95

Program on Technology Innovation: Carbon Nanotube Water Filtration  

Science Conference Proceedings (OSTI)

Carbon nanotubes--tiny cylinders of rolled-up graphite sheets with diameters in the range of 1--3 nanometers--have been enjoying an iconic status among nanoscience researchers for a long time. However, despite their spectacular properties, commercial applications of carbon nanotubes have been few. Now, a new commercial technology is exploiting one of the most remarkable properties of this carbon nanotube molecule: the ability of the tiny carbon nanotube pore to transport water at an extremely fast rate, ...

2011-04-14T23:59:59.000Z

96

The Roadmap for Developing Carbon Nanotube Reinforced Metal  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2010. Symposium, Nanotube Reinforced Metal Matrix Composites II. Presentation Title, The ...

97

Polysulfone /Multi-Walled Carbon Nanotube Hybrid Nanocomposites  

Science Conference Proceedings (OSTI)

Abstract Scope, Polyurethane (PU)/ polysulfone/multi-walled carbon nanotubes ( MWNTs) hybrid nanocomposites of different weight ratio have been prepared ...

98

Characterization of the Metal/Carbon Nanotube Interface Using  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2010. Symposium, Nanotube Reinforced Metal Matrix Composites II. Presentation Title ...

99

Nanostructuring of Microporous Carbons with Carbon Nanotubes for ...  

Science Conference Proceedings (OSTI)

Presentation Title, Nanostructuring of Microporous Carbons with Carbon Nanotubes for Efficient Carbon Dioxide Capture. Author(s), Stephen C. Hawkins,  ...

100

Nanotube Boiler 1 Abstract--Controlled copper evaporation at attogram  

E-Print Network (OSTI)

Nanotube Boiler 1 Abstract-- Controlled copper evaporation at attogram level from individual carbon nanotube (CNT) vessels, which we call nanotube boilers, is investigated experimentally, and ionization in these CNT boilers, which can serve as sources for mass transport and deposition in nanofluidic

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Electronics Properties of Single-Walled Twisted Carbon Nanotubes  

Science Conference Proceedings (OSTI)

Electronic properties are calculated and simulited by using density functional theory based on the nonequilibrium Green's function when a zigzag single-wall carbon nanotube (SCNTs) is twisted. We found that the twist of the single-wall carbon nanotube ... Keywords: single-wall twisted carbon nanotubes, nonequilibrium Green's function, density functional theory, electric structure, electronic transmission

Qing-fang Fu; Da-peng Hao; Xiao-mi Yan; Dao-wei He; Zhi-shun Chen; Li-guang Wang; Terence K. S. W

2011-04-01T23:59:59.000Z

102

Vertically aligned GaN nanotubes - Fabrication and current image analysis  

Science Conference Proceedings (OSTI)

In this work, we present a one step formation method of nanotubes on GaN film, and then map out local current of nanotubes. GaN nanotubes were formed by inductively coupled plasma (ICP) etching and found that tops of these nanotubes were hexagonal with ... Keywords: C-AFM, FESEM, GaN, ICP, Nanotubes

Shang-Chao Hung; Yan-Kuin Su; Shoou-Jinn Chang; Y. H. Chen

2006-11-01T23:59:59.000Z

103

A Man with an Umbilicated Papule of the Hand: What Is Your Diagnosis?  

E-Print Network (OSTI)

Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introduction. Ecthyma contagiosum is a zoonotic disease caused by the parapoxvirus that causes “sore mouth ” in sheep and goats and orf in human. Case Presentation. A 61-year-old sheep farmer presented with a painful non-pruritic lesion on the left hand that had been present for approximately 5 weeks. Physical examination demonstrated a 1 cm pearly, umbilicated papule with raised borders. A biopsy showed an asymmetrical nodule with parakeratotic crust and acanthosis with thin epidermal strands extending deeply in the underlying dermis. Marked edema, capillary proliferation and extensive lymphocytic infiltration was also present.

Article Id; Deba P. Sarma; Meredith Cox; Paige Walter; William Crisler; Christopher Huerter

2010-01-01T23:59:59.000Z

104

Inorganic nanotubes and electro-fluidic devices fabricated therefrom  

DOE Patents (OSTI)

Nanofluidic devices incorporating inorganic nanotubes fluidly coupled to channels or nanopores for supplying a fluid containing chemical or bio-chemical species are described. In one aspect, two channels are fluidly interconnected with a nanotube. Electrodes on opposing sides of the nanotube establish electrical contact with the fluid therein. A bias current is passed between the electrodes through the fluid, and current changes are detected to ascertain the passage of select molecules, such as DNA, through the nanotube. In another aspect, a gate electrode is located proximal the nanotube between the two electrodes thus forming a nanofluidic transistor. The voltage applied to the gate controls the passage of ionic species through the nanotube selected as either or both ionic polarities. In either of these aspects the nanotube can be modified, or functionalized, to control the selectivity of detection or passage.

Yang, Peidong (Kensington, CA); Majumdar, Arunava (Orinda, CA); Fan, Rong (Pasadena, CA); Karnik, Rohit (Cambridge, MA)

2011-03-01T23:59:59.000Z

105

First principles study of structure and lithium storage in inorganic nanotubes  

E-Print Network (OSTI)

The exact structure of layered inorganic nanotubes is difficult to determine, but this information is vital to using atomistic calculations to predict nanotube properties. A multi-walled nanotube with a circular cross ...

Tibbetts, Kevin (Kevin Joseph)

2009-01-01T23:59:59.000Z

106

Engineering carbon nanostructures : development of novel aerogel-nanotube composites and optimization techniques for nanotube growth  

E-Print Network (OSTI)

Carbon aerogels offer several unique advantages which make them ideal for evaluating a metal's ability to catalyze nanotube growth, including in situ carbothermic reduction of oxidized nanoparticles to their catalytic ...

Steiner, Stephen Alan, III

2006-01-01T23:59:59.000Z

107

Laser ablative synthesis of carbon nanotubes  

DOE Patents (OSTI)

An improved method for the production of single walled carbon nanotubes that utilizes an RF-induction heated side-pumped synthesis chamber for the production of such. Such a method, while capable of producing large volumes of carbon nanotubes, concurrently permits the use of a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization. The method of the present invention utilizes a free electron laser operating at high average and peak fluence to illuminate a rotating and translating graphite/catalyst target to obtain high yields of SWNTs without the use of a vacuum chamber.

Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA); Park, Cheol (Yorktown, VA)

2010-03-02T23:59:59.000Z

108

CARBON NANOTUBES: PROPERTIES AND APPLICATIONS  

DOE Green Energy (OSTI)

From the beginnings of research on carbon nanotubes, one of the major applications envisioned was hydrogen storage for fuel-cell powered cars and trucks. Subsequent theoretical models gave mixed results, the most pessimistic indicating that the fundamental H2-SWNT interaction was similar to flat graphite (physisorption) with only modest binding energies implying cryogenic operation at best. New material families with encouraging measured properties have emerged, and materials modeling has gained enormously in predictive power, sophistication, and the ability to treat a realistically representative number of atoms. One of the new materials, highly porous carbide-derived carbons (CDC), is the subject of an add-on to this grant awarded to myself and Taner Yildirim (NIST). Results from the add-on led eventually to a new 3-year award DE-FG02-08ER46522 “From Fundamental Understanding to Predicting New Nanomaterials for High Capacity Hydrogen Storage”, $1000K, (05/31/2008 - 05/01/2011) with Taner Yildirim and myself as co-PI’s.

Fischer, John, E.

2009-07-24T23:59:59.000Z

109

Carbon Nanotube Transistors: Capacitance Measurements, Localized Damage, And Use As Gold Scaffolding .  

E-Print Network (OSTI)

??Carbon nanotubes are incredible materials with interesting mechanical and electrical properties. This thesis presents diverse experiments based on carbon nanotube transistors. We measured the capacitance… (more)

Donev, Luke

2009-01-01T23:59:59.000Z

110

Electrical, electromagnetic and structural characteristics of carbon nanotube-polymer nanocomposites  

E-Print Network (OSTI)

DDL. Partial replacement of carbon fiber by carbon black incarbon nanotubes and carbon fibers. Composites, Part A.carbon nanotubes for carbon fiber-epoxy composites. Journal

Park, Sung-Hoon

2009-01-01T23:59:59.000Z

111

Fabrication of high thermal conductivity arrays of carbon nanotubes and their composites  

DOE Patents (OSTI)

Methods and apparatus are described for fabrication of high thermal conductivity arrays of carbon nanotubes and their composites. A composition includes a vertically aligned nanotube array including a plurality of nanotubes characterized by a property across substantially all of the vertically aligned nanotube array. A method includes depositing a vertically aligned nanotube array that includes a plurality of nanotubes; and controlling a deposition rate of the vertically aligned nanotubes array as a function of an in situ monitored property of the plurality of nanotubes.

Geohegan, David B. (Knoxville, TN); Ivanov, Ilya N. (Knoxville, TN); Puretzky,; Alexander A. (Knoxville, TN)

2010-07-27T23:59:59.000Z

112

Platinated ultrathin films made of carbon nanotubes  

Science Conference Proceedings (OSTI)

In this study a promising approach for a novel fuel cell catalyst layer is shown using films of carbon nanotubes (CNTs) formed by the layer-by-layer (LbL) method. A special focus is on the dispensing procedure of CNTs in water what is one of the most ...

Timo Bohnenberger; Frank Steinhäußer; Jovan Matovic; Ulrich Schmid

2012-08-01T23:59:59.000Z

113

Diffusion through Carbon Nanotube Semipermeable membranes  

DOE Green Energy (OSTI)

The goal of this project is to measure transport through CNTs and study effects of confinement at molecular scale. This work is motivated by several simulation papers in high profile journals that predict significantly higher transport rates of gases and liquids through carbon nanotubes as compared with similarly-sized nanomaterials (e.g. zeolites). The predictions are based on the effects of confinement, atomically smooth pore walls and high pore density. Our work will provide the first measurements that would compare to and hopefully validate the simulations. Gas flux is predicted to be >1000X greater for SWNTs versus zeolitesi. A high flux of 6-30 H2O/NT/ns {approx} 8-40 L/min for a 1cm{sup 2} membrane is also predicted. Neutron diffraction measurements indicate existence of a 1D water chain within a cylindrical ice sheet inside carbon nanotubes, which is consistent with the predictions of the simulation. The enabling experimental platform that we are developing is a semipermeable membrane made out of vertically aligned carbon nanotubes with gaps between nanotubes filled so that the transport occurs through the nanotubes. The major challenges of this project included: (1) Growth of CNTs in the suitable vertically aligned configuration, especially the single wall carbon nanotubes; (2) Development of a process for void-free filling gaps between CNTs; and (3) Design of the experiments that will probe the small amounts of analyte that go through. Knowledge of the behavior of water upon nanometer-scale confinement is key to understanding many biological processes. For example, the protein folding process is believed to involve water confined in a hydrophobic environment. In transmembrane proteins such as aquaporins, water transport occurs under similar conditions. And in fields as far removed as oil recovery and catalysis, an understanding of the nanoscale molecular transport occurring within the nanomaterials used (e.g. zeolites) is the key to process optimization. Furthermore, advancement of many emerging nanotechnologies in chemistry and biology will undoubtedly be aided by an understanding confined water transport, particularly the details of hydrogen bonding and solvation that become crucial on this length scale. We can envision several practical applications for our devices, including desalination, gas separations, dialysis, and semipermeable fabrics for protection against CW agents etc. The single wall carbon nanotube membranes will be the key platform for applications because they will allow high transport rates of small molecules such as water and eliminate solvated ions or CW agents.

Bakajin, O

2006-02-13T23:59:59.000Z

114

Spin Control: New Technique Sorts Nanotubes by Length  

Science Conference Proceedings (OSTI)

... Unfortunately, the methods for manufacturing carbon nanotubes always create a large percentage of nanojunk in the mix—clumps of carbon ...

2012-10-18T23:59:59.000Z

115

Available Technologies: Boron Nitride Nanotubes with Modified Surfaces  

Nano- & Micro-technology; Software and IT ; Licensing Interest Form Receive Customized Tech Alerts. Boron Nitride Nanotubes with Modified Surfaces . IB-2331 and IB-2332 .

116

Current-controlled nanotube growth and zone re?nement  

so, the original nanotube is consumed by the catalyst nano-particle and a higher-quality CNT is grown and ejected from the trailing end.

117

In Situ Band Gap Engineering of Carbon Nanotubes  

VOLUME 79, NUMBER 11 PHYSICAL REVIEW LETTERS 15SEPTEMBER 1997 In Situ Band Gap Engineering of Carbon Nanotubes Vincent H. Crespi* and Marvin L. Cohen

118

Towards structural health monitoring in carbon nanotube reinforced composites  

E-Print Network (OSTI)

An experimental investigation was conducted to understand the non-destructive evaluation (NDE) capabilities of carbon nanotubes (CNTs) of several network architectures towards structural health monitoring (SHM). As ...

Wang, Wennie

2013-01-01T23:59:59.000Z

119

NIST Uncovers Reliability Issues for Carbon Nanotubes in ...  

Science Conference Proceedings (OSTI)

... whether nanotubes can replace copper wiring in next-generation electronics. ... Copper wires transport power and other signals among all the parts of ...

2012-10-15T23:59:59.000Z

120

Electrical Conductance of Single TiO2 Nanotube Devices  

Science Conference Proceedings (OSTI)

As fabricated TiO2 nanotubes with different wall thicknesses were annealed either in ... carbon foam saturated with SiO2 aerogel for heat insulation purposes.

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Carbon nanotube applications for CMOS back-end processing  

E-Print Network (OSTI)

Carbon nanotubes are a recently discovered material with excellent mechanical, thermal, and electronic properties. In particular, they are potential ballistic transporters and are theorized to have thermal conductivities ...

Wu, Tan Mau, 1979-

2005-01-01T23:59:59.000Z

122

Application of Carbon Nanotubes – Energy to Bioelectronic Sensor  

Science Conference Proceedings (OSTI)

This presentation aims to capture those recent research efforts in synthesis and applications of carbon nanotubes in Li-ion battery, bioelectronic sensor and high  ...

123

Fatigue Deformation and Failure of Carbon Nanotube-loaded ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The cyclic deformation of individual fibers has been studied in the textile ... Our room temperature experiments on plain and carbon nanotube-

124

Photoexcitation of the triplet exciton in single wall carbon nanotubes  

E-Print Network (OSTI)

The carbon nanotube photoexcitation spectrum is dominated by excitonic transitions, rather than interband transitions between continuum states. There are eight distinct excitonic transitions (four singlet and four triplet), ...

Santos, Tiffany S.

125

Single Wall Carbon Nanotube/Polyacrylonitrile Composite Fiber .  

E-Print Network (OSTI)

??Single Wall Carbon Nanotubes (SWNTs), discovered in 1993, have good mechanical, electrical and thermal properties. Polyacrylonitrile (PAN) is an important fiber for textiles as well… (more)

Liang, Jianghong

2004-01-01T23:59:59.000Z

126

Carbon nanotube reinforced polyacrylonitrile and poly(etherketone) fibers .  

E-Print Network (OSTI)

??The graphitic nature, continuous structure, and high mechanical properties of carbon nanotubes (CNTs) make them good candidate for reinforcing polymer fiber. The different types of… (more)

Jain, Rahul

2009-01-01T23:59:59.000Z

127

Carbon Nanotubes at Interface of Electronics, Aeronautics Show ...  

Thermal Conductivity Arrays of Carbon Nanotubes and their Composites, U.S. Patent 7, 763, 353, issued July 27, 2010. Lead Inventor David B. Geohegan

128

Characterization of composites with aligned carbon nanotubes (CNTs) as reinforcement  

E-Print Network (OSTI)

Carbon nanotubes' (CNTs) superlative combination of electrical, thermal, and especially mechanical properties make them ideal candidates for composite reinforcement. Nanocomposites and hybrid composite architectures employing ...

García, Enrique J

2006-01-01T23:59:59.000Z

129

Novel Stack Concepts: Patterned Aligned Carbon Nanotubes as Electrodes...  

NLE Websites -- All DOE Office Websites (Extended Search)

Stack Concepts: Patterned Aligned Carbon Nanotubes as Electrodes in MEAs Di-Jia Liu Chemical Engineering Division Argonne National Laboratory Presentation at Fuel Cell Kickoff...

130

Spray-On “Super Nanotubes” - Materials Technology @ TMS  

Science Conference Proceedings (OSTI)

Apr 25, 2013 ... This new coating material consists of multiwall carbon nanotubes and a ceramic made of silicon, boron, carbon, and nitrogen. Boron boosts the ...

131

'Metal-Decorated' Nanotubes Hold Promise for Fuel Cells  

Science Conference Proceedings (OSTI)

... This computer model shows how titanium atoms (dark blue) can attach above the centers of single-walled carbon nanotubes (light blue). ...

2010-10-21T23:59:59.000Z

132

NETL: Releases & Briefs - Nanotube activation and disorder may...  

NLE Websites -- All DOE Office Websites (Extended Search)

researchers are suggesting that a chemically and physically disordered array of activated carbon nanotubes may provide a solution to hydrogen storage problems. According to NETL...

133

Study of interactions between single-wall carbon nanotubes and ...  

Science Conference Proceedings (OSTI)

Jul 10, 2012 ... Abstract Carbon nanotubes (CNT) exhibit interesting electrical and mechanical properties. However, the insolubility of CNT in either water or ...

134

Tuning the Properties of Carbon Nanotubes by Deformation ...  

Science Conference Proceedings (OSTI)

... Back to Tuning the Properties of Carbon Nanotubes by Deformation. Last modified 31-May-2002 by website owner: NCNR (attn: Bill Kamitakahara).

135

Boron Nitride Nanotube Reinforced Metal and Ceramic Composites ...  

Science Conference Proceedings (OSTI)

Functional Composites: Fluorescent Carbon Nanotubes in Silica Aerogel ... Novel Metallo-Organic Derived Ti-Si-Cr-C-N Nanocomposite Coatings: Part II ...

136

Ultrathin Alumina Coated Carbon Nanotubes as Anodes for High ...  

Science Conference Proceedings (OSTI)

Presentation Title, Ultrathin Alumina Coated Carbon Nanotubes as Anodes for High Capacity Li-Ion Battery. Author(s), Indranil Lahiri, Wonbong Choi. On-Site ...

137

Density controlled carbon nanotube array electrodes  

DOE Patents (OSTI)

CNT materials comprising aligned carbon nanotubes (CNTs) with pre-determined site densities, catalyst substrate materials for obtaining them and methods for forming aligned CNTs with controllable densities on such catalyst substrate materials are described. The fabrication of films comprising site-density controlled vertically aligned CNT arrays of the invention with variable field emission characteristics, whereby the field emission properties of the films are controlled by independently varying the length of CNTs in the aligned array within the film or by independently varying inter-tubule spacing of the CNTs within the array (site density) are disclosed. The fabrication of microelectrode arrays (MEAs) formed utilizing the carbon nanotube material of the invention is also described.

Ren, Zhifeng F. (Newton, MA); Tu, Yi (Belmont, MA)

2008-12-16T23:59:59.000Z

138

Synthesis of polycrystalline SnO{sub 2} nanotubes on carbon nanotube template for anode material of lithium-ion battery  

Science Conference Proceedings (OSTI)

Polycrystalline tin oxide nanotubes have been prepared by a layer-by-layer technique on carbon nanotubes template. Firstly, the surface of carbon nanotubes was modified by polyelectrolyte. Then, a uniform layer of tin oxide nanoparticles was formed on the positive charged surface of carbon nanotubes via a redox process. At last, the polycrystalline tin oxide nanotubes were synthesized after calcination at 650 deg. C in air for 3 h. The as-synthesized polycrystalline nanotubes with large surface area exhibit finer lithium storage capacity and cycling performance, which shows the potentially interesting application in lithium-ion battery.

Du Ning; Zhang Hui; Chen Bindi; Ma Xiangyang; Huang Xiaohua; Tu Jiangping [State Key Lab of Silicon Materials and Department of Material Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Yang Deren [State Key Lab of Silicon Materials and Department of Material Science and Engineering, Zhejiang University, Hangzhou 310027 (China)], E-mail: mseyang@zju.edu.cn

2009-01-08T23:59:59.000Z

139

Paper-mediated controlled densification and low temperature transfer of carbon nanotube forests for electronic interconnect application  

Science Conference Proceedings (OSTI)

We report on the fabrication and characterization of densified and transferred carbon nanotube forests for electronic interconnect application. A simple, low cost and quality method is developed for densifying vertically-aligned carbon nanotube (VA-CNTs) ... Keywords: Carbon nanotube, Carbon nanotube resistance, Carbon nanotube transfer, Densification, Post-growth processing, Young's modulus

Di Jiang; Teng Wang; Si Chen; Lilei Ye; Johan Liu

2013-03-01T23:59:59.000Z

140

Integration and electrical characterization of carbon nanotube via interconnects  

Science Conference Proceedings (OSTI)

Carbon nanotubes (CNTs) are considered a promising material for interconnects in the future generations of microchips because of their low electrical resistance and excellent mechanical stability. In particular, CNT-based contacts appear advantageous ... Keywords: CNT, Carbon nanotubes, Contact, Electrical characterization, Integration, Interconnect

Nicolo' Chiodarelli; Yunlong Li; Daire J. Cott; Sofie Mertens; Nick Peys; Marc Heyns; Stefan De Gendt; Guido Groeseneken; Philippe M. Vereecken

2011-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Carbon nanotubes as photoacoustic molecular imaging agents in living mice  

E-Print Network (OSTI)

Carbon nanotubes as photoacoustic molecular imaging agents in living mice ADAM DE LA ZERDA1 not shown to target a diseased site in living subjects. Here we show that single-walled carbon nanotubes were verified ex vivo using Raman microscopy. Photoacoustic imaging of targeted single-walled carbon

Khuri-Yakub, Butrus T. "Pierre"

142

Geometrical tunability of plasmon excitations of double concentric metallic nanotubes  

SciTech Connect

The plasmon frequencies of a general double concentric metallic nanotube (NT) are obtained by using the plasmon hybridization method. Theoretical calculations indicate that there are four distinct plasmon modes for the system. It is shown that these two alternating layers of dielectric and metal have a greater geometrical tunability than the single metallic nanotubes of similar dimensions.

Moradi, Afshin [Department of Nano Science, Kermanshah University of Technology, Kermanshah 67178-63766 (Iran, Islamic Republic of) and Department of Nano Science, Institute for Studies in Theoretical Physics and Mathematics (IPM), Tehran 19395-5531 (Iran, Islamic Republic of)

2012-06-15T23:59:59.000Z

143

Characterization of single wall carbon nanotubes by nonane preadsorption  

E-Print Network (OSTI)

­25 A° range; however nanotubes with $10­16 A° diameters make the main fraction. Nano- tubes are bundled measurement. A filler rod was utilized to decrease the dead volume of the adsorption tube and to enhance be very helpful for determining a fraction of opened tubes for car- bon nanotube materials with tube

Liu, Jie

144

Computational study of compressive loading of carbon nanotubes  

Science Conference Proceedings (OSTI)

A reduced-order general continuum method is used to examine the mechanical behavior of single-walled carbon nanotubes (CNTs) under compressive loading and unloading conditions. Quasi-static solutions are sought where the total energy of the system is ... Keywords: carbon nanotube, component, finite element method, mechanical properties

Yang Yang; William W. Liou

2010-03-01T23:59:59.000Z

145

Computational mechanical modeling of the behavior of carbon nanotubes  

Science Conference Proceedings (OSTI)

This paper presents a computational method for the mechanical simulation of carbon nanotubes, whose complexity is linear on the number of atoms. The regularity of a graphene lattice at its energy ground permits the definition of a tiling scheme that ... Keywords: carbon nanotubes, computational method, mathematical modeling, molecular dynamics, numerical simulation

Maria Morandi Cecchi; Alberto Giovanni Busetto

2007-08-01T23:59:59.000Z

146

Multiscale analysis of the core nanotube in a nanocomposite system  

Science Conference Proceedings (OSTI)

Carbon nanotube reinforced polymer composites have novel properties that make them useful in a wide variety of applications and there has been numerous studies to predict the overall bulk properties of these nanocomposites. Theoretical studies to understand ... Keywords: Carbon nanotube, Interphase, Molecular dynamics, Nanocomposite

Vinu Unnikrishnan; J. N. Reddy

2012-02-01T23:59:59.000Z

147

Apparatus for the laser ablative synthesis of carbon nanotubes  

DOE Patents (OSTI)

An RF-induction heated side-pumped synthesis chamber for the production of carbon nanotubes. Such an apparatus, while capable of producing large volumes of carbon nanotubes, concurrently provides a simplified apparatus that allows for greatly reduced heat up and cool down times and flexible flowpaths that can be readily modified for production efficiency optimization.

Smith, Michael W. (Newport News, VA); Jordan, Kevin (Newport News, VA)

2010-02-16T23:59:59.000Z

148

Imaging Carbon Nanotubes Magdalena Preciado Lpez, David Zahora, Monica Plisch  

E-Print Network (OSTI)

, the electrons would collide with air molecules and quickly lose their energy. Since electrons are electrically nanotubes using image analysis software. The goals are to learn more about carbon nanotube growth, develop that the side of the tip contacts the tube well before the bottom of the tip. This causes the profile

Gaeta, Alexander L.

149

Book review Carbon Nanotube Science: Synthesis, Properties and Appli-  

E-Print Network (OSTI)

Book review Carbon Nanotube Science: Synthesis, Properties and Appli- cations, Peter J.F. Harris in the nanotube discovery is dis- cussed in the first chapter of this book), a few years after ful- lerenes were of the nanotechnology era ­ you'll find their pictures on book covers, in newspaper articles and magazine centerfolds

Harris, Peter J F

150

Bending and shear moduli of single-walled carbon nanotubes  

Science Conference Proceedings (OSTI)

Elastic properties of single-walled carbon nanotubes (SWCNT) obtained experimentally and computationally are reviewed. Attention is paid particularly on the evaluation of Young's and shear moduli of SWCNT. A finite element method (FEM) previously presented ... Keywords: Finite element method, Mechanical properties, Single-walled carbon nanotubes

Cho W. S. To

2006-02-01T23:59:59.000Z

151

Delay uncertainty in single- and multi-wall carbon nanotube interconnects  

Science Conference Proceedings (OSTI)

Carbon nanotube (CNT) has become the promising candidate for replacing the traditional copper based interconnect systems in future VLSI technology nodes. This paper analyzes delay uncertainty due to crosstalk in the Single- and Multi-wall CNT bundle ... Keywords: carbon nanotube (CNT), crosstalk delay, double-wall carbon nanotube (DWCNT), multi-wall carbon nanotube (MWCNT), single-wall carbon nanotube (SWCNT), very large scale integration (VLSI)

Debaprasad Das; Hafizur Rahaman

2012-07-01T23:59:59.000Z

152

Energy Carrier Transport In Surface-Modified Carbon Nanotubes  

E-Print Network (OSTI)

Carbon nanotubes are made into films or bulks, their surface or junction morphology in the networks can be modified to obtain desired electrical transport properties by various surface modification methods. The methods include incorporation of organic molecules or inorganic nanoparticles, debundling of nanotubes by dispersing agents, and microwave irradiation. Because carbon nanotubes have unique carrier transport characteristics along a sheet of graphite in a cylindrical shape, the properties can be dramatically changed by the modification. This is ideal for developing high-performance materials for thermoelectric and photovoltaic energy conversion applications. In this research, decoration of various organic/inorganic nanomaterials on carbon nanotubes was employed to enhance their electrical conductivity, to improve thermoelectric power factor by modulating their electrical conductance and thermopower, or to obtain n-type converted carbon nanotube. The electrical conductivity of double-wall nanotubes (DWNTs) decorated with tetrafluoro-tetracyanoquinodimethane (F4TCNQ) was increased up to 5.9 × 10^5 S/m. The sheet resistances were measured to be 42 ?/sq at 75% of transmittance for HNO3/SOCl2-treated DWNT films, making their electrical conductivities 200~300% better than those of the pristine DWNT films. A series of experiments at different ion concentrations and reaction time periods were systematically performed in order to find optimum nanomaterial formation conditions and corresponding electronic transport changes for better thermoelectric power factor. For example, the thermoelectric power factors were improved by ~180% with F4TCNQ on DWNTs, ~200% with Cu on SWNTs, and ~140% with Fe on single-walled nanotubes (SWNTs). Also SWNTs was converted from p-type to n-type with a large thermopower (58 ?V/K) by using polyethyleneimine (PEI) without vacuum or controlled environment. This transport behavior is believed to be from charge interactions resulted from the difference between the work functions/reduction potentials of nanotubes and nanomaterials. In addition, different dispersing agents were utilized with DWNT and SWNTs to see a debundling effect in a film network. The highest electrical conductivity of ~1.72×10^6 S/m was obtained from DWNT film which was fabricated with a nanotube solution dispersed by chlorosulfonic acid. Debundling of nanotubes in the film network has been demonstrated to be a critical parameter in order to get such high electrical property. In the last experiment, Au nanoparticle decoration on carbon nanotube bundle was performed and a measurement of themophysical properties has done before and after modifying carbon nanotube surface. Carbon nanotube bundle, herein, was bridged on microdevice to enable the measurement work. This study demonstrates a first step toward a breakthrough in order to extract the potential of carbon nanotubes regarding electron transport properties.

Ryu, Yeontack

2012-12-01T23:59:59.000Z

153

Synthetic nanotubes lay foundation for new technology: Artificial pores  

NLE Websites -- All DOE Office Websites (Extended Search)

Synthetic nanotubes lay foundation for new technology: Artificial pores Synthetic nanotubes lay foundation for new technology: Artificial pores mimic key features of natural pores By Tona Kunz * July 17, 2012 Tweet EmailPrint Scientists have overcome key design hurdles to expand the potential uses of nanopores and nanotubes. The creation of smart nanotubes with selective mass transport opens up a wider range of applications for water purification, chemical separation and fighting disease. Nanopores and their rolled up version, nanotubes, consist of atoms bonded to each other in a hexagonal pattern to create an array of nanometer-scale openings or channels. This structure creates a filter that can be sized to select which molecules and ions pass into drinking water or into a cell. The same filter technique can limit the release of chemical by-products

154

Rotational actuator of motor based on carbon nanotubes  

DOE Patents (OSTI)

A rotational actuator/motor based on rotation of a carbon nanotube is disclosed. The carbon nanotube is provided with a rotor plate attached to an outer wall, which moves relative to an inner wall of the nanotube. After deposit of a nanotube on a silicon chip substrate, the entire structure may be fabricated by lithography using selected techniques adapted from silicon manufacturing technology. The structures to be fabricated may comprise a multiwall carbon nanotube (MWNT), two in plane stators S1, S2 and a gate stator S3 buried beneath the substrate surface. The MWNT is suspended between two anchor pads and comprises a rotator attached to an outer wall and arranged to move in response to electromagnetic inputs. The substrate is etched away to allow the rotor to freely rotate. Rotation may be either in a reciprocal or fully rotatable manner.

Zettl, Alexander K. (Kensington, CA); Fennimore, Adam M. (Berkeley, CA); Yuzvinsky, Thomas D. (Berkeley, CA)

2008-11-18T23:59:59.000Z

155

Modeling of interface behavior in carbon nanotube composites.  

Science Conference Proceedings (OSTI)

This research focuses on the development of a constitutive model for carbon nanotube polymer composites incorporating nanoscale attributes of the interface between the nanotube and polymer. Carbon nanotube polymer composites exhibit promising properties, as structural materials and the current work will motivate improvement in their load transfer capabilities. Since separation events occur at different length and time scales, the current work also addresses the challenge of multiscale modeling in interpreting inputs at different length and time scales. The nanoscale phase separation phenomena are investigated using molecular dynamics (MD) simulations. The simulations based on MD provide grounds for developing a cohesive zone model for the interface based on laws of thermodynamics.

Hammerand, Daniel Carl; Awasthi, Amnaya P. (Texas A& M University, College Station, TX); Lagoudas, Dimitris C. (Texas A& M University, College Station, TX)

2006-05-01T23:59:59.000Z

156

Structure and electronic properties of saturated and unsaturated gallium nitride nanotubes  

DOE Green Energy (OSTI)

The atomic and electronic structures of saturated and unsaturated GaN nanotubes along the [001] direction with (100) lateral facets are studied using first-principles calculations. Atomic relaxation of nanotubes shows that appreciable distortion occurs in the unsaturated nanotubes. All the nanotubes considered, including saturated and unsaturated ones, exhibit semiconducting, with a direct band gap. Surface states arisen from the threefold-coordinated N and Ga atoms at the lateral facets exist inside the bulk-like band gap. When the nanotubes saturated with hydrogen, these dangling bond bands are removed from the band gap, but the band gap decreases with increasing the wall thickness of the nanotubes.

Wang, Zhiguo; Wang, Shengjie; Li, Jingbo; Gao, Fei; Weber, William J.

2009-11-05T23:59:59.000Z

157

Fibrous composites comprising carbon nanotubes and silica  

DOE Patents (OSTI)

Fibrous composite comprising a plurality of carbon nanotubes; and a silica-containing moiety having one of the structures: (SiO).sub.3Si--(CH.sub.2).sub.n--NR.sub.1R.sub.2) or (SiO).sub.3Si--(CH.sub.2).sub.n--NCO; where n is from 1 to 6, and R.sub.1 and R.sub.2 are each independently H, CH.sub.3, or C.sub.2H.sub.5.

Peng, Huisheng (Shanghai, CN); Zhu, Yuntian Theodore (Cary, NC); Peterson, Dean E. (Los Alamos, NM); Jia, Quanxi (Los Alamos, NM)

2011-10-11T23:59:59.000Z

158

Growth and deterministic assembly of single stranded carbon nanotube  

E-Print Network (OSTI)

The ability to control the shape, position, alignment, length and assembly of carbon nanotubes over large areas has become an essential but very difficult goal in the field of nanotechnology. Current assembly efforts for ...

Doddabasanagouda, Sunil

2006-01-01T23:59:59.000Z

159

Carbon nanotube field effect transistors for power application  

E-Print Network (OSTI)

Carbon nanotubes (CNTs) are nanometer-diameter cylinders formed from rolled-up graphene sheets which have found widespread interests due to their many excellent electrical properties. In particular, most of them are direct ...

Pan, Tao, S.M. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

160

Thermal properties of nanowires and nanotubes : modeling and experiments  

E-Print Network (OSTI)

Nanowires and nanotubes have drawn a great deal of recent attention for such potential applications as lasers, transistors, biosensors, and thermoelectric energy converters. Although the thermal properties of nanowires can ...

Dames, Christopher Eric

2006-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Evaluations of single walled carbon nanotubes using resonance Raman spectroscopy  

E-Print Network (OSTI)

This work reports the results of two studies which use resonance Raman scattering to evaluate the vibrational properties of single walled carbon nanotubes (SWNTs). In the first study, we report an evaluation of second-order ...

Brar, Victor W. (Victor Watson), 1981-

2004-01-01T23:59:59.000Z

162

Optical studies of DNA-wrapped carbon nanotubes  

E-Print Network (OSTI)

This thesis presents a series of detailed optical studies of phonon-assisted relaxation processes in DNA-wrapped single walled carbon nanotubes. Using resonance Raman spectroscopy (RRS) and photoluminescence spectroscopy ...

Chou, Shin Grace

2006-01-01T23:59:59.000Z

163

Carbon Nanotube Materials for Substrate Enhanced Control of Catalytic Activity  

DOE Green Energy (OSTI)

Carbon SWNTs are attractive materials for supporting electrocatalysts. The properties of SWNTs are highly tunable and controlled by the nanotube's circumferential periodicity and their surface chemistry. These unique characteristics suggest that architectures constructed from these types of carbon support materials would exhibit interesting and useful properties. Here, we expect that the structure of the carbon nanotube support will play a major role in stabilizing metal electrocatalysts under extreme operating conditions and suppress both catalyst and support degradation. Furthermore, the chemical modification of the carbon nanotube surfaces can be expected to alter the interface between the catalyst and support, thus, enhancing the activity and utilization of the electrocatalysts. We plan to incorporate discrete reaction sites into the carbon nanotube lattice to create intimate electrical contacts with the catalyst particles to increase the metal catalyst activity and utilization. The work involves materials synthesis, design of electrode architectures on the nanoscale, control of the electronic, ionic, and mass fluxes, and use of advanced optical spectroscopy techniques.

Heben, M.; Dillon, A. C.; Engtrakul, C.; Lee, S.-H.; Kelley, R. D.; Kini, A. M.

2007-05-01T23:59:59.000Z

164

New concepts in energy and mass transport within carbon nanotubes  

E-Print Network (OSTI)

The unique structure of carbon nanotubes (CNTs) contributes to their distinguished properties, making them useful in nanotechnology. CNTs have been explored for energy transport in next-generation, such as light-emitting ...

Choi, Wonjoon, Ph. D. Massachusetts Institute of Technology

2012-01-01T23:59:59.000Z

165

Deformation Mechanisms in Carbon Nanotube/Epoxy Composites  

Science Conference Proceedings (OSTI)

Presentation Title, Deformation Mechanisms in Carbon Nanotube/Epoxy Composites ... fracture toughness and delamination damage resistance, and the associated ... Effect of Piassava Fiber Incorporation In Morphological, Thermal and ... Semiconductors: Producing Bulk Sized Nanocomposites Using Electric Currents ...

166

A Shell Theory for Chiral Single-Wall Carbon Nanotubes  

E-Print Network (OSTI)

In this paper, we propose a characterization of the mechanical response of the linearly elastic shell we associate to a single-wall carbon nanotube of arbitrary chirality. In Bajaj et al. 2013, we gave such a characterization in the case of zigzag and armchair nanotubes; in particular, we showed that the orthotropic response we postulated for the associated shells is to become isotropic in the graphene-limit, that is, when the shell radius grows bigger and bigger. Here we give an explicit recipe to construct the generally anisotropic response of the shell associated to a nanotube of any chirality in terms of the response of the shell associated to a related zigzag or armchair nanotube. The expected coupling of mechanical effects that anisotropy entrains is demonstrated in the case of a torsion problem, where the axial extension accompanying twist is determined analytically and found in good agreement with the available experimental data.

Antonino Favata; Paolo Podio-Guidugli

2013-06-28T23:59:59.000Z

167

Carbon Nanotube Growth Using Ni Catalyst in Different Layouts  

E-Print Network (OSTI)

Vertically aligned carbon nanotubes have been grown using Ni as catalyst by plasma enhanced chemical vapor deposition system (PECVD) in various pre-patterned substrates. Ni was thermally evaporated on silicon substrates ...

Nguyen, H. Q.

168

Can a Carbon Nanotube Pierce through a Phospholipid Bilayer?  

E-Print Network (OSTI)

Great efficiency to penetrate into living cells is attributed to carbon nanotubes due to a number of direct and indirect observations of carbon nanotubes inside the cells. However, a direct evidence of physical translocation of nanotubes through phospholipid bilayers and the exact microscopic mechanism of their penetration into cells are still lacking. In order to test one of the inferred translocation mechanisms, namely the spontaneous piercing through the membrane induced only by thermal motion, we calculate the energy cost associated with the insertion of a carbon nanotube into a model phospholipid bilayer using the Single Chain Mean Field theory which is particularly suitable for the accurate measurements of equilibrium free energies. We find that the energy cost of the bilayer rupture is quite high compared to the energy of thermal motion. This conclusion may indirectly support other energy dependent translocation mechanisms such as, for example, endocytosis.

Sergey Pogodin; Vladimir A. Baulin

2010-10-07T23:59:59.000Z

169

Would Diamond Nanorods Be Stronger than Fullerene Nanotubes?  

E-Print Network (OSTI)

, silicon nitride, silicon carbide, or aluminum oxide), which has made nanotubes attractive structures yield strengths for the strongest fibers typically used in fiber-reinforced composites (e.g., graphite

170

Calorimetric studies of small-molecule adsorption to carbon nanotubes  

E-Print Network (OSTI)

Isothermal titration calorimetry (ITC) was developed as a technique for qualitatively comparing the heat of absorption of small molecules to single-walled carbon nanotubes (SWCNTs). In agreement with other studies, it was ...

Glab, Kristin Lena

2009-01-01T23:59:59.000Z

171

Diverse Chemiresistors Based upon Covalently Modified Multiwalled Carbon Nanotubes  

E-Print Network (OSTI)

A diverse array of multiwalled carbon nanotube (MWCNT) sensory materials have been synthesized and used to create sensors capable of identifying volatile organic compounds (VOCs) on the basis of their functional groups. ...

Swager, Timothy Manning

172

Carbon nanotubes as piezoresistive microelectromechanical sensors: Theory and experiment  

E-Print Network (OSTI)

Carbon-nanotube (CNT) -based strain sensors have the potential to overcome some of the limitations in small-scale force/displacement sensing technologies due to their small size and high sensitivity to strain. A better ...

Culpepper, Martin Luther

173

Energy storage in carbon nanotube super-springs  

E-Print Network (OSTI)

A new technology is proposed for lightweight, high density energy storage. The objective of this thesis is to study the potential of storing energy in the elastic deformation of carbon nanotubes (CNTs). Prior experimental ...

Hill, Frances Ann

2008-01-01T23:59:59.000Z

174

In Silico Assembly And Nanomechanical Characterization Of Carbon Nanotube Buckypaper  

E-Print Network (OSTI)

Carbon nanotube sheets or films, also known as 'buckypaper', have been proposed for use in actuating, structural and filtration systems, based in part on their unique and robust mechanical properties. Computational modeling ...

Cranford, Steven Wayne

175

Carbon nanotube-based nanoscale ad hoc networks  

Science Conference Proceedings (OSTI)

Recent developments in nanoscale electronics allow current wireless technologies to function in nanoscale environments. Especially due to their incredible electrical and electromagnetic properties, carbon nanotubes are promising physical phenomenon that ...

Baris Atakan; Ozgur B. Akan

2010-06-01T23:59:59.000Z

176

Carbon nanotube processing and chemistry for electronic interconnect applications  

E-Print Network (OSTI)

Carbon nanotubes possess many properties that are ideally suited for electronic applications, such as metallic/semiconducting behavior and ballistic transport. Specifically, in light of mounting concerns over the increasing ...

Wu, Tan Mau, 1979-

2008-01-01T23:59:59.000Z

177

Building and testing organized architectures of carbon nanotubes  

Science Conference Proceedings (OSTI)

This paper will focus on the directed assembly of multiwalled carbon nanotubes on various substrates into highly organized structures that include vertically and horizontally oriented arrays, ordered fibers and porous membranes. The concept of growing ...

R. Vajtai; Bingqing Wei; Yung Joon Jung; Anyuan Cao; S. K. Biswas; G. Ramanath; P. M. Ajayan

2003-12-01T23:59:59.000Z

178

Gas Adsorption on Heterogeneous Single-Walled Carbon Nanotube...  

NLE Websites -- All DOE Office Websites (Extended Search)

the adsorption of C, Xe, and Ar onto bundles of closed-ended SWNTs. The Single-walled carbon nanotubes (SWNTs) are of inter- est as gas adsorbents because of their unique...

179

Microfabricated breath sensor based on carbon nanotubes for respiration monitoring  

Science Conference Proceedings (OSTI)

A microfabricated breath sensor based on multi-walled carbon nanotubes (MWCNTs) has been designed, developed and tested. This sensor has a simple capacitor structure, including a pair of metal electrodes fabricated by micromachining, which are then coated ...

Hai Liu; Xiaohang Chen; Dong Xu; Zhongyu Hou; Yafei Zhang

2009-01-01T23:59:59.000Z

180

Carbon Nanotubes and Nano-Structure Manufacturing at TJNAF |...  

Office of Science (SC) Website

What began in 2001 as an academic investigation of how to make carbon nanotubes with a free-electron laser (FEL) has moved into a new phase. Researchers at NASA's Langley Research...

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Applications and nanotoxicity of carbon nanotubes and graphene in biomedicine  

Science Conference Proceedings (OSTI)

Owing to their unique mechanical, electrical, optical, and thermal properties, carbon nanostructures including carbon nanotubes and graphenes show great promise for advancing the fields of biology and medicine. Many reports have demonstrated the promise ...

Caitlin Fisher; Amanda E. Rider; Zhao Jun Han; Shailesh Kumar; Igor Levchenko; Kostya Ostrikov

2012-01-01T23:59:59.000Z

182

Flexible solid-state paper based carbon nanotube supercapacitor  

Science Conference Proceedings (OSTI)

This paper presents a flexible solid-state supercapacitor of high energy density. The electrodes of the supercapacitor are made of porous and absorbent cotton paper coated with single-wall carbon nanotubes. To ensure all solid-state configuration

Shan Hu; Rajesh Rajamani; Xun Yu

2012-01-01T23:59:59.000Z

183

Chemically driven carbon-nanotube-guided thermopower waves  

E-Print Network (OSTI)

Theoretical calculations predict that by coupling an exothermic chemical reaction with a nanotube or nanowire possessing a high axial thermal conductivity, a self-propagating reactive wave can be driven along its length. ...

Choi, Wonjoon

184

Carbon Nanotube Membranes: Carbon Nanotube Membranes for Energy-Efficient Carbon Sequestration  

SciTech Connect

Broad Funding Opportunity Announcement Project: Porifera is developing carbon nanotube membranes that allow more efficient removal of CO2 from coal plant exhaust. Most of today’s carbon capture methods use chemical solvents, but capture methods that use membranes to draw CO2 out of exhaust gas are potentially more efficient and cost effective. Traditionally, membranes are limited by the rate at which they allow gas to flow through them and the amount of CO2 they can attract from the gas. Smooth support pores and the unique structure of Porifera’s carbon nanotube membranes allows them to be more permeable than other polymeric membranes, yet still selective enough for CO2 removal. This approach could overcome the barriers facing membrane-based approaches for capturing CO2 from coal plant exhausts.

None

2010-03-01T23:59:59.000Z

185

Production of single-walled carbon nanotube grids  

Science Conference Proceedings (OSTI)

A method of forming a nanotube grid includes placing a plurality of catalyst nanoparticles on a grid framework, contacting the catalyst nanoparticles with a gas mixture that includes hydrogen and a carbon source in a reaction chamber, forming an activated gas from the gas mixture, heating the grid framework and activated gas, and controlling a growth time to generate a single-wall carbon nanotube array radially about the grid framework. A filter membrane may be produced by this method.

Hauge, Robert H; Xu, Ya-Qiong; Pheasant, Sean

2013-12-03T23:59:59.000Z

186

Ferrimagnetic Spin Wave Resonance and Superconductivity in Carbon Nanotubes  

E-Print Network (OSTI)

The phenomenon of ferrimagnetic spin wave resonance [uncompensated antiferromagnetic spin wave resonance] has been detected for the first time. It has been observed in carbon nanotubes, produced by high energy ion beam modification of diamond single crystals in $\\ $ direction. Peculiarities of spin wave resonance observed allow to insist on the formation in given nanotubes of $s^+$ superconductivity at room temperature, coexisting with uncompensated antiferromagnetic ordering.

Dmitri Yerchuck; Yauhen Yerchak; Vyacheslav Stelmakh; Alla Dovlatova; Andrey Alexandrov

2013-05-14T23:59:59.000Z

187

Catalytic activity of ZrO2 nanotube arrays prepared by anodization method  

Science Conference Proceedings (OSTI)

ZrO2 nanotube arrays were prepared by anodization method in aqueous electrolyte containing (NH4)2SO4 and NH4F. The morphology and structure of nanotube arrays were characterized through scanning ...

Xixin Wang; Jianling Zhao; Xiaorui Hou; Qi He; Chengchun Tang

2012-01-01T23:59:59.000Z

188

Towards improved spinnability of chemical vapor deposition generated multi-walled carbon nanotubes  

E-Print Network (OSTI)

and Dresselhaus G. 1997 From Carbon Fibers to Nanotubes inV VGCF Vapor Grown Carbon Fiber X XRD X-ray Diffraction ixgraphite whiskers, carbon fibers, and carbon nanotubes, each

McKee, Gregg Sturdivant Burke

2008-01-01T23:59:59.000Z

189

Theoretical and simulation tools for electron transfer and chain reactions in single walled carbon nanotubes  

E-Print Network (OSTI)

Single walled carbon nanotubes (SWNT) are cylindrical sheets of graphene whose electronic structures and diameters are determined by their chiralities. Current synthetic methods produce batches of nanotubes containing a ...

Nair, Nitish

2009-01-01T23:59:59.000Z

190

Single walled carbon nanotubes functionally adsorbed to biopolymers for use as chemical sensors  

DOE Patents (OSTI)

Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

Johnson, Jr., Alan T. (Philadelphia, PA); Gelperin, Alan (Princeton, NJ); Staii, Cristian (Madison, WI)

2011-07-12T23:59:59.000Z

191

Modeling and control of a silicon substrate heater for carbon nanotube growth experiments  

E-Print Network (OSTI)

The precision engineering research group at MIT is working on carbon nanotube growth experiments on silicon substrates and in microfabricated silicon devices, to try to produce improved bulk nanotube growth. For this thesis, ...

Held, David (David A.)

2005-01-01T23:59:59.000Z

192

Study of fire retardant behavior of carbon nanotube membranes and carbon nanofiber paper in carbon fiber  

E-Print Network (OSTI)

Study of fire retardant behavior of carbon nanotube membranes and carbon nanofiber paper in carbon Accepted 14 January 2010 Available online 20 January 2010 A B S T R A C T Single-walled carbon nanotube (SWCNT) and multi-walled carbon nanotube (MWCNT) membranes (buckypaper) and carbon nanofiber (CNF) paper

Das, Suman

193

Aligned carbon nanotubes array by DC glow plasma etching for supercapacitor  

Science Conference Proceedings (OSTI)

To open the end of carbon nanotubes and make these ends connect with functional carboxyl group, aligned carbon nanotubes (CNTs) arrays was etched by DC glow oxygen-argon plasma. With these open-ended carbon nanotubes array as electrodematerials to build ...

Yongfeng Luo, Xiaojia Li, Zhiqiang Gong, Zhongzhi Sheng, Xiaofang Peng, Qunying Mou, Mengdong He, Xianjun Li, Hong Chen

2013-01-01T23:59:59.000Z

194

Carbon Nanotube-Containing Structures, Methods Of Making, And Processes Using Same  

DOE Patents (OSTI)

Carbon nanotube structures are disclosed in which nanotubes are disposed over a porous support such as a foam, felt, mesh, or membrane. Techniques of making these structures are also disclosed. In some of these techniques, a support is pretreated with a templated surfactant composition to assist with the formation of a nanotube layer.

Wang, Yong (Richland, WA); Chin, Ya-Huei (Richland, WA); Gao, Yufei (Blue Bell, PA); Aardahl, Christopher L. (Richland, WA); Stewart, Terri L. (Richland, WA)

2004-11-30T23:59:59.000Z

195

Carbon nanotube-containing structures, methods of making, and processes using same  

DOE Patents (OSTI)

Carbon nanotube structures are disclosed in which nanotubes are disposed over a porous support such as a foam, felt, mesh, or membrane. Techniques of making these structures are also disclosed. In some of these techniques, a support is pretreated with a templated surfactant composition to assist with the formation of a nanotube layer.

Wang, Yong (Richland, WA); Chin, Ya-Huei (Richland, WA); Gao, Yufei (Blue Bell, PA); Aardahl, Christopher L. (Richland, WA); Stewart, Terri L. (Richland, WA)

2006-03-14T23:59:59.000Z

196

Carbon nanotube diameter selection by pretreatment of metal catalysts on surfaces  

DOE Patents (OSTI)

A new and useful nanotube growth substrate conditioning processes is herein disclosed that allows the growth of vertical arrays of carbon nanotubes where the average diameter of the nanotubes can be selected and/or controlled as compared to the prior art.

Hauge, Robert H. (Houston, TX); Xu, Ya-Qiong (Houston, TX); Shan, Hongwei (Houston, TX); Nicholas, Nolan Walker (South Charleston, WV); Kim, Myung Jong (Houston, TX); Schmidt, Howard K. (Cypress, TX); Kittrell, W. Carter (Houston, TX)

2012-02-28T23:59:59.000Z

197

Nanocomposite fibers and film containing polyolefin and surface-modified carbon nanotubes  

DOE Patents (OSTI)

Methods for modifying carbon nanotubes with organic compounds are disclosed. The modified carbon nanotubes have enhanced compatibility with polyolefins. Nanocomposites of the organo-modified carbon nanotubes and polyolefins can be used to produce both fibers and films having enhanced mechanical and electrical properties, especially the elongation-to-break ratio and the toughness of the fibers and/or films.

Chu,Benjamin (Setauket, NY); Hsiao, Benjamin S. (Setauket, NY)

2010-01-26T23:59:59.000Z

198

Method for making nanotubes and nanoparticles  

DOE Patents (OSTI)

The present invention is an apparatus and method for producing nano-scale tubes and particles. The apparatus comprises novel electrodes for use in arc discharge techniques. The electrodes have interior conduits for delivery and withdrawal of material from the arc region where product is formed. In one embodiment, the anode is optionally made from more than one material and is termed a compound anode. The materials used in the compound anode assist in the reaction that forms product in the arc region of the apparatus. The materials assist either by providing reaction ingredients, catalyst, or affecting the reaction kinetics. Among other uses, the inventive apparatus is used to produce nanotubes and nanoparticles having a variety of electrical and mechanical properties.

Zettl, Alexander Karlwalter (Kensington, CA); Cohen, Marvin Lou (Piedmont, CA)

2000-01-01T23:59:59.000Z

199

Waveguide-integrated electroluminescent carbon nanotubes  

E-Print Network (OSTI)

Carbon based optoelectronic devices promise to revolutionize modern integrated circuits by combining outstanding electrical and optical properties into a unified technology. By coupling nanoelectronic devices to nanophotonic structures functional components such as nanoscale light emitting diodes, narrow-band thermal emitters, cavity controlled detectors and wideband electro optic modulators can be realized for chipscale information processing. These devices not only allow the light-matter interaction of low-dimensional systems to be studied, but also provide fundamental building blocks for high bandwidth on-chip communication. Here we demonstrate how light from an electrically-driven carbon-nanotube can be coupled directly into a photonic waveguide architecture. We realize wafer scale, broadband sources integrated with nanophotonic circuits allowing for propagation of light over centimeter distances. Moreover, we show that the spectral properties of the emitter can be controlled directly on chip with passive...

Khasminskaya, Svetlana; Flavel, Benjamin S; Pernice, Wolfram H P; Krupke, Ralph

2013-01-01T23:59:59.000Z

200

Microfluidic sieve using intertwined, free-standing carbon nanotube mesh as active medium  

DOE Patents (OSTI)

A microfluidic sieve having a substrate with a microfluidic channel, and a carbon nanotube mesh. The carbon nanotube mesh is formed from a plurality of intertwined free-standing carbon nanotubes which are fixedly attached within the channel for separating, concentrating, and/or filtering molecules flowed through the channel. In one embodiment, the microfluidic sieve is fabricated by providing a substrate having a microfluidic channel, and growing the intertwined free-standing carbon nanotubes from within the channel to produce the carbon nanotube mesh attached within the channel.

Bakajin, Olgica (San Leandro, CA); Noy, Aleksandr (Belmont, CA)

2007-11-06T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

LDRD final report : chromophore-functionalized aligned carbon nanotube arrays.  

SciTech Connect

The goal of this project was to expand upon previously demonstrated single carbon nanotube devices by preparing a more practical, multi-single-walled carbon nanotube (SWNT) device. As a late-start, proof-of-concept project, the work focused on the fabrication and testing of chromophore-functionalized aligned SWNT field effect transistors (SWNT-FET). Such devices have not yet been demonstrated. The advantages of fabricating aligned SWNT devices include increased device cross-section to improve sensitivity to light, elimination of increased electrical resistance at nanotube junctions in random mat devices, and the ability to model device responses. The project did not achieve the goal of fabricating and testing chromophore-modified SWNT arrays, but a new SWNT growth capability was established that will benefit future projects. Although the ultimate goal of fabricating and testing chromophore-modified SWNT arrays was not achieved, the work did lead to a new carbon nanotube growth capability at Sandia/CA. The synthesis of dense arrays of horizontally aligned SWNTs is a developing area of research with significant potential for new discoveries. In particular, the ability to prepare arrays of carbon nanotubes of specific electronic types (metallic or semiconducting) could yield new classes of nanoscale devices.

Vance, Andrew L.; Yang, Chu-Yeu Peter; Krafcik, Karen Lee

2011-09-01T23:59:59.000Z

202

Quasiparticle energy studies of bulk semiconductors, surfaces and nanotubes  

DOE Green Energy (OSTI)

Effects of many-body effects on electronic excitation energies (quasiparticle band structure) of these materials are explored. GW approximation, including local field effects, for self-energy operator is used to calculate quasi-particle energies. The newly discovered carbon nanotubes are studied; structural stability and band structures are calculated. BN nanotubes are also studied, and their stability is predicted. Unexpected electronic features are predicted for both systems. Filling of carbon nanotubes with metal atoms and the doping of BN nanotubes by carbon and other impurites is also studied. The occupied surface states at H/Si(111)-(1{times}1) surface are studied; it is shown that the electronic structure requires a full quasiparticle calculation even for this simple chemisorption system. The core level shift of the Si 2p levels for atoms near the H/Si(111)-(1{times}1) surface is calculated; a simple first order perturbation theory using pseudopotential and the local density approximation gives good results for the photoemission spectra of the core electrons. The quasiparticle energies of bulk hexagonal BN and those of an isolated BN sheet are studied; this provides an understanding of the quasiparticle band structure of BN nanotubes. A nearly free electron state with a wavefunction in the interlayer or vacuum region composes the bottom of the conduction bands. A mixed-space formalism is presented for calculating the dynamical screening effects and electron self-energy operator in solids; this provides an efficient algorithm to calculate quasiparticle energies for large systems.

Blase, X.F.

1994-12-01T23:59:59.000Z

203

Immersing carbon nano-tubes in cold atomic gases  

E-Print Network (OSTI)

We investigate the sympathetic relaxation of a free-standing, vibrating carbon nano-tube that is mounted on an atom chip and is immersed in a cloud of ultra-cold atoms. Gas atoms colliding with the nano-tube excite phonons via a Casimir-Polder potential. We use Fermi's Golden Rule to estimate the relaxation rates for relevant experimental parameters and develop a fully dynamic theory of relaxation for the multi-mode phononic field embedded in a thermal atomic reservoir. Based on currently available experimental data, we identify the relaxation rates as a function of atom density and temperature that are required for sympathetic ground state cooling of carbon nano-tubes.

C. T. Weiß; P. V. Mironova; J. Fortágh; W. P. Schleich; R. Walser

2013-07-08T23:59:59.000Z

204

Electrochemical Deposition of Iron Nanoneedles on Titanium Oxide Nanotubes  

Science Conference Proceedings (OSTI)

Iron as a catalyst has wide applications for hydrogen generation from ammonia, photodecomposition of organics, and carbon nanotube growth. Tuning the size and shape of iron is meaningful for improving the catalysis efficiency. It is the objective of this work to prepare nanostructured iron with high surface area via electrochemical deposition. Iron nanoneedles were successfully electrodeposited on Ti supported TiO2 nanotube arrays in a chlorine-based electrolyte containing 0.15 M FeCl2 {center_dot} 4H2O and 2.0 M HCl. Transmission electron microscopic analysis reveals that the average length of the nanoneedles is about 200 nm and the thickness is about 10 nm. It has been found that a high overpotential at the cathode made of Ti/TiO2 nanotube arrays is necessary for the formation of the nanoneedles. Cyclic voltammetry test indicates that the electrodeposition of iron nanoneedles is a concentration-limited process.

Gan Y. X.; Zhang L.; Gan B.J.

2011-10-01T23:59:59.000Z

205

Confinement of hydrogen at high pressure in carbon nanotubes  

DOE Patents (OSTI)

A high pressure hydrogen confinement apparatus according to one embodiment includes carbon nanotubes capped at one or both ends thereof with a hydrogen-permeable membrane to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough. A hydrogen confinement apparatus according to another embodiment includes an array of multi-walled carbon nanotubes each having first and second ends, the second ends being capped with palladium (Pd) to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough as a function of palladium temperature, wherein the array of carbon nanotubes is capable of storing hydrogen gas at a pressure of at least 1 GPa for greater than 24 hours. Additional apparatuses and methods are also presented.

Lassila, David H. (Aptos, CA); Bonner, Brian P. (Livermore, CA)

2011-12-13T23:59:59.000Z

206

Fluorescent single walled nanotube/silica composite materials  

DOE Patents (OSTI)

Fluorescent composites of surfactant-wrapped single-walled carbon nanotubes (SWNTs) were prepared by exposing suspensions of surfactant-wrapped carbon nanotubes to tetramethylorthosilicate (TMOS) vapor. Sodium deoxycholate (DOC) and sodium dodecylsulphate (SDS) were the surfactants. No loss in emission intensity was observed when the suspension of DOC-wrapped SWNTs were exposed to the TMOS vapors, but about a 50% decrease in the emission signal was observed from the SDS-wrapped SWNTs nanotubes. The decrease in emission was minimal by buffering the SDS/SWNT suspension prior to forming the composite. Fluorescent xerogels were prepared by adding glycerol to the SWNT suspensions prior to TMOS vapor exposure, followed by drying the gels. Fluorescent aerogels were prepared by replacing water in the gels with methanol and then exposing them to supercritical fluid drying conditions. The aerogels can be used for gas sensing.

Dattelbaum, Andrew M.; Gupta, Gautam; Duque, Juan G.; Doorn, Stephen K.; Hamilton, Christopher E.; DeFriend Obrey, Kimberly A.

2013-03-12T23:59:59.000Z

207

Carbon nanotubes grown on bulk materials and methods for fabrication  

DOE Patents (OSTI)

Disclosed are structures formed as bulk support media having carbon nanotubes formed therewith. The bulk support media may comprise fibers or particles and the fibers or particles may be formed from such materials as quartz, carbon, or activated carbon. Metal catalyst species are formed adjacent the surfaces of the bulk support material, and carbon nanotubes are grown adjacent the surfaces of the metal catalyst species. Methods employ metal salt solutions that may comprise iron salts such as iron chloride, aluminum salts such as aluminum chloride, or nickel salts such as nickel chloride. Carbon nanotubes may be separated from the carbon-based bulk support media and the metal catalyst species by using concentrated acids to oxidize the carbon-based bulk support media and the metal catalyst species.

Menchhofer, Paul A. (Clinton, TN); Montgomery, Frederick C. (Oak Ridge, TN); Baker, Frederick S. (Oak Ridge, TN)

2011-11-08T23:59:59.000Z

208

Effects of catalyst pretreatment for carbon nanotube growth  

E-Print Network (OSTI)

The effects of pretreatment of iron catalyst for carbon nanotube (CNT) growth was studied. CNTs were grown on Fe/A1203 (1/10 nm) thin-film catalyst deposited on silicon substrates via exposure to C2H4 in a thermal chemical ...

Morgan, Caitlin D

2007-01-01T23:59:59.000Z

209

Electronic and transport properties of nanotubes Jean-Christophe Charlier*  

E-Print Network (OSTI)

and the elastic properties of the graphene sheet left . The bonds are perpendicular to the surface of the sheet because of the special shape of the graphene Fermi surface and the restriction of the electronic bands-binding model of graphene 683 C. Zone-folding approximation 684 1. Metallic nanotubes 684 2. Semiconducting

Wu, Zhigang

210

Low-dimensional carbon nanotube and graphene devices  

E-Print Network (OSTI)

microscopy . . . . . . . . . . . . . . . . . . . . . . . 126 5.3 Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 5.3.1 Dilution refrigerator . . . . . . . . . . . . . . . . . . . . . . . . 128 5.3.2 Low temperature AFM... element to combine with and extend ex- isting microelectronics devices and processes. Their intrinsic transport is already well studied, but industrial use is hindered by the incompatibilities between nanotube syn- thesis processes and device fabrication...

Scard, Philip

2010-10-12T23:59:59.000Z

211

DOI: 10.1002/adma.200601748 Carbon Nanotube Aerogels**  

E-Print Network (OSTI)

DOI: 10.1002/adma.200601748 Carbon Nanotube Aerogels** By Mateusz B. Bryning, Daniel E. Milkie, Mohammad F. Islam, Lawrence A. Hough, James M. Kikkawa, and Arjun G. Yodh* Aerogels are ultralight, highly. Microscopically, aerogels are composed of tenuous networks of clustered nanoparticles, and the materials often

Islam, Mohammad F.

212

Nuclear Magnetism and Electronic Order in 13 C Nanotubes  

E-Print Network (OSTI)

Nuclear Magnetism and Electronic Order in 13 C Nanotubes Bernd Braunecker,1 Pascal Simon,1 on nuclear magnetism in one dimension. If the electrons are in the metallic, Luttinger liquid regime, we show that even a very weak hyperfine coupling to the 13C nuclear spins has a striking effect: The system

Braunecker, Bernd

213

LDRD final report : energy conversion using chromophore-functionalized carbon nanotubes.  

SciTech Connect

With the goal of studying the conversion of optical energy to electrical energy at the nanoscale, we developed and tested devices based on single-walled carbon nanotubes functionalized with azobenzene chromophores, where the chromophores serve as photoabsorbers and the nanotube as the electronic read-out. By synthesizing chromophores with specific absorption windows in the visible spectrum and anchoring them to the nanotube surface, we demonstrated the controlled detection of visible light of low intensity in narrow ranges of wavelengths. Our measurements suggested that upon photoabsorption, the chromophores isomerize to give a large change in dipole moment, changing the electrostatic environment of the nanotube. All-electron ab initio calculations were used to study the chromophore-nanotube hybrids, and show that the chromophores bind strongly to the nanotubes without disturbing the electronic structure of either species. Calculated values of the dipole moments supported the notion of dipole changes as the optical detection mechanism.

Vance, Andrew L.; Zifer, Thomas; Zhou, Xinjian; Leonard, Francois Leonard; Wong, Bryan Matthew; Kane, Alexander; Katzenmeyer, Aaron Michael; Krafcik, Karen Lee

2010-09-01T23:59:59.000Z

214

Quantitative displacement measurement of a nanotube cantilever with nanometer accuracy using epifluorescence microscopy  

SciTech Connect

A method to measure the deflection of a nanotube cantilever with nanometer accuracy in an air or liquid environment is presented. We attached fluorescent dyes at the end of a nanotube to detect its deflection. The nanotube cantilever was fabricated with a multiwalled carbon nanotube that is attached to the end of an electrochemically etched tungsten tip, and it was imaged in an epifluorescence microscope system. The fluorescence intensity distribution of the fluorescent particles at the end of the nanotube was approximated with a Gaussian and fitted by least-squares method. Finally, we were able to measure the displacement of the nanotube cantilever during electrostatic actuation with positional accuracy of a few nanometers. This technique can be applied to a manipulator or a force transducer on related a few piconewton forces.

Park, Hyojun; Kwon, Soongeun; Kim, Soohyun [Department of Mechanical Engineering, School of Mechanical, Aerospace and Systems Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2009-05-15T23:59:59.000Z

215

Ion Exclusion by Sub 2-nm Carbon Nanotube Pores  

Science Conference Proceedings (OSTI)

Carbon nanotubes offer an outstanding platform for studying molecular transport at nanoscale, and have become promising materials for nanofluidics and membrane technology due to their unique combination of physical, chemical, mechanical, and electronic properties. In particular, both simulations and experiments have proved that fluid flow through carbon nanotubes of nanometer size diameter is exceptionally fast compared to what continuum hydrodynamic theories would predict when applied on this length scale, and also, compared to conventional membranes with pores of similar size, such as zeolites. For a variety of applications such as separation technology, molecular sensing, drug delivery, and biomimetics, selectivity is required together with fast flow. In particular, for water desalination, coupling the enhancement of the water flux with selective ion transport could drastically reduce the cost of brackish and seawater desalting. In this work, we study the ion selectivity of membranes made of aligned double-walled carbon nanotubes with sub-2 nm diameter. Negatively charged groups are introduced at the opening of the carbon nanotubes by oxygen plasma treatment. Reverse osmosis experiments coupled with capillary electrophoresis analysis of permeate and feed show significant anion and cation rejection. Ion exclusion declines by increasing ionic strength (concentration) of the feed and by lowering solution pH; also, the highest rejection is observed for the A{sub m}{sup Z{sub A}} C{sub n}{sup Z{sub C}} salts (A=anion, C=cation, z= valence) with the greatest Z{sub A}/Z{sub C} ratio. Our results strongly support a Donnan-type rejection mechanism, dominated by electrostatic interactions between fixed membrane charges and mobile ions, while steric and hydrodynamic effects appear to be less important. Comparison with commercial nanofiltration membranes for water softening reveals that our carbon nanotube membranes provides far superior water fluxes for similar ion rejection capabilities.

Fornasiero, F; Park, H G; Holt, J K; Stadermann, M; Grigoropoulos, C P; Noy, A; Bakajin, O

2008-04-09T23:59:59.000Z

216

Carbon nanotubes and graphene in aqueous surfactant solutions : molecular simulations and theoretical modeling  

E-Print Network (OSTI)

This thesis describes combined molecular simulations and theoretical modeling studies, supported by experimental observations, on properties and applications of carbon nanotubes (CNTs) and graphene sheets dispersed in ...

Lin, Shangchao

2012-01-01T23:59:59.000Z

217

Desktop systems for manufacturing carbon nanotube films by chemical vapor deposition  

E-Print Network (OSTI)

Carbon nanotubes (CNTs) exhibit exceptional electrical, thermal, and mechanical properties that could potentially transform such diverse fields as composites, electronics, cooling, energy storage, and biological sensing. ...

Kuhn, David S. (David Scott)

2007-01-01T23:59:59.000Z

218

The investigation of interactions between single walled carbon nanotubes and flexible chain molecules  

E-Print Network (OSTI)

Anisotropic nanoparticles, such as inorganic nanowires and carbon nanotubes, are promising materials for a wide range of technological applications including transparent conductors, thin film transistors, photovoltaic ...

Jeng, Esther Shu-Hsien

2010-01-01T23:59:59.000Z

219

Go No-Go Decision: Pure, Undoped, Single Walled Carbon Nanotubes for Vehicular Hydrogen Storage  

Fuel Cell Technologies Publication and Product Library (EERE)

This document provides information about the go/no-go decision on pure, undoped single walled carbon nanotubes for vehicular hydrogen storage.

220

Temperature and Frequency Dependent Conduction Mechanisms Within Bulk Carbon Nanotube Materials.  

E-Print Network (OSTI)

??The resistance of three types of bulk carbon nanotube (CNT) materials (floating catalyst CNT yarn, forest grown CNT yarn, and super acid spun CNT fiber)… (more)

Bulmer, John Simmons

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

APPLICATIONS OF MULTIWALL CARBON NANOTUBE COMPOSITES: MECHANICAL, ELECTRICAL AND THERMAL PROPERTIES.  

E-Print Network (OSTI)

??Carbon nanotubes have now been a subject of intense research for approaching two decades. Although a short time relative to most conventional materials, much hype… (more)

Weisenberger, Matthew Collins

2007-01-01T23:59:59.000Z

222

Tensile testing and stabilization/carbonization studies of polyacrylonitrile/carbon nanotube composite fibers .  

E-Print Network (OSTI)

??This study focuses on the processing, structure and properties of polyacrylonitrile (PAN)/ carbon nanotube (CNT) composite carbon fibers. Small diameter PAN/CNT based carbon fibers have… (more)

Lyons, Kevin Mark

2012-01-01T23:59:59.000Z

223

Polyacrylonitrile / carbon nanotube composite fibers: effect of various processing parameters on fiber structure and properties .  

E-Print Network (OSTI)

??This study elucidates the effect of various processing parameters on polyacrylonitrile (PAN) /carbon nanotube (CNT) composite fiber structure and properties. Interaction between PAN and MWNT… (more)

Choi, Young Ho

2010-01-01T23:59:59.000Z

224

Aligned TiO2 Nanotubes as Long Durability Anodes for Lithium-Ion ...  

Science Conference Proceedings (OSTI)

Aligned TiO2 Nanotubes as Long Durability Anodes for Lithium-Ion Batteries · Aniline Coated Carbon Cryogel with Improved Cyclic Stability for Supercapacitor  ...

225

Synthesis and characterization of next-generation multifunctional material architectures : aligned carbon nanotube carbon matrix nanocomposites  

E-Print Network (OSTI)

Materials comprising carbon nanotube (CNT) aligned nanowire (NW) polymer nanocomposites (A-PNCs) have emerged as promising architectures for next-generation multifunctional applications. Enhanced operating regimes, such ...

Stein, Itai Y

2013-01-01T23:59:59.000Z

226

STUDY OF PROPANE ADSORPTION ISOTHERM ON PURIFIED HIPCO SINGLE-WALLED CARBON NANOTUBES.  

E-Print Network (OSTI)

??Isotherms of one atom thick film of adsorption for propane on purified Hipco single-walled carbon nanotube were experimentally studied at 6 different temperatures ranging from… (more)

Furuhashi, Toyohisa

2009-01-01T23:59:59.000Z

227

Carbon-nanotube-based membranes for water desalination by membrane distillation.  

E-Print Network (OSTI)

??This work investigates ways to fabricate composite macro-structures made of carbon nanotubes in combination with polymers and metals to enhance membrane lifespan and performance. Carbon… (more)

Dumee, Ludovic

2011-01-01T23:59:59.000Z

228

Study of the reaction rate of gold nanotube synthesis from sacrificial silver nanorods through the galvanic replacement method  

Science Conference Proceedings (OSTI)

An investigation was carried out about the gold nanotube synthesis via a galvanic replacement reaction. The progress of the gold nanotube synthesis was investigated using electron microscopy and UV-Vis spectroscopy. In addition, the reaction rates of ...

Sunil Kwon; Hyunbae Dong; Sang-Yup Lee

2010-01-01T23:59:59.000Z

229

Recent trends in the microwave-assisted synthesis of metal oxide nanoparticles supported on carbon nanotubes and their applications  

Science Conference Proceedings (OSTI)

The study of coating carbon nanotubes with metal/oxides nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon nanotubes in various applications, it is necessary to attach functional groups or other ...

Sarah C. Motshekga; Sreejarani K. Pillai; Suprakas Sinha Ray; Kalala Jalama; Rui. W. M. Krause

2012-01-01T23:59:59.000Z

230

Template-based Ferromagnetic Nanowires and Nanotubes: Fabrication and Characterization  

E-Print Network (OSTI)

his dissertation describes experimental studies of the structures and properties, and their correlations in ferromagnetic nanowires and nanotubes fabricated using porous templates. Ferromagnetic Ni and Fe nanowires with diameters 30 ~ 250 nm were electroplated into the pores of anodic aluminum oxide membranes. The effects of nanowire diameter on structural and magnetic properties were investigated. The microstructures of these nanowires were studied using X-ray diffraction and selected-area electron diffraction measurements. The magnetic properties of the nanowires were investigated using magnetic hysteresis measurements and magnetic force microscopy. Additionally, ferromagnetic Ni-P nanotubes were fabricated using an electroless chemical deposition method. Structure and composition analyses were conducted using X-ray diffraction and energy-dispersive spectroscopy. The magnetic properties of the nanotube arrays and the electronic properties of individual nanotubes were studied. Hysteresis measurements revealed that the 250-nm diameter Ni nanowires had a poor squareness in their hysteresis loops, indicating the existence of multi-domain states. In comparison, the squareness in the hysteresis loops of 60-nm and 30-nm Ni nanowires was much improved, suggesting the existence of single domain states in these smaller diameter nanowires. Magnetic force microscopy measurements confirmed the magnetic domain structures suggested by magnetic hysteresis measurements. Similar investigations of Fe nanowires with diameters of 250 nm and 60 nm found that they all have multidomain magnetic structures. This is expected based on their material properties and polycrystalline structures. Furthermore, magnetic structures of Y-branches and multi-wire clusters were also studied using magnetic force microscopy. The as-prepared Ni-P nanotubes had an amorphous structure. Following a heat treatment, however, a structural phase transformation from the amorphous phase to a crystalline phase was observed using X-ray diffraction measurements. The tetragonal crystalline phase of Ni3P and the face-centered-cubic phase of Ni were confirmed via simulations by the GSAS software. The high Ni3P content accounts for the semiconducting behavior and a low magnetic anisotropy observed in the Ni-P nanotubes.

Wei, Zhiyuan

2013-05-01T23:59:59.000Z

231

Electric moulding of dispersed lipid nanotubes into a nanofluidic device  

E-Print Network (OSTI)

Hydrophilic nanotubes formed by lipid molecules have potential applications as platforms for chemical or biological events occurring in an attolitre volume inside a hollow cylinder. Here, we have integrated the lipid nanotubes (LNTs) by applying an AC electric field via plug-in electrode needles placed above a substrate. The off-chip assembly method has the on-demand adjustability of an electrode configuration, enabling the dispersed LNT to be electrically moulded into a separate film of parallel LNT arrays in one-step. The fluorescence resonance energy transfer technique as well as the digital microscopy visualised the overall filling of gold nanoparticles up to the inner capacity of an LNT film by capillary action, thereby showing the potential of this flexible film for use as a high-throughput nanofluidic device where not only is the endo-signalling and product in each LNT multiplied but also the encapsulated objects are efficiently transported and reacted.

Hiroshi Frusawa; Tatsuhiko Manabe; Eri Kagiyama; Ken Hirano; Naohiro Kameta; Mitsutoshi Masuda; Toshimi Shimizu

2013-07-13T23:59:59.000Z

232

Flash Ignition and Initiation of Explosives-Nanotubes Mixture  

DOE Green Energy (OSTI)

The recent astounding discoveries of ignition in single-walled carbon nanotubes (SWNTs) after exposure to an ordinary photographic flash, (1) other formulations of carbons containing noble metals, (2) and polyaniline nanofibers (3) prompted us to explore a possible further instigation of explosive materials. Here, we report that an ignition and initiation process, further leading to actual detonation, does occur for explosives in lax contact with carbon nanotubes that are prone to opto-thermal activity via a conventional flashbulb. Optical ignition and initiation of explosives could thus far only be accomplished through lasers, (4) with specific characteristic of high power, pulse length, wavelength, and a small target area that greatly inhibit their applications. Our results have the implication that explosives with opto-thermally active SWNTs formulations are new ideal candidates for remote optical triggering of safety apparatus such as the firing of bolts on space shuttles rockets and aircraft exit doors, and for controlled burning of explosives as actuators.

Manaa, M R; Mitchell, A R; Garza, R G; Pagoria, P F; Watkins, B E

2005-05-25T23:59:59.000Z

233

Preparation of supported electrocatalyst comprising multiwalled carbon nanotubes  

SciTech Connect

A process for preparing a durable non-precious metal oxygen reduction electrocatalyst involves heat treatment of a ball-milled mixture of polyaniline and multiwalled carbon nanotubes in the presence of a Fe species. The catalyst is more durable than catalysts that use carbon black supports. Performance degradation was minimal or absent after 500 hours of operation at constant cell voltage of 0.40 V.

Wu, Gang; Zelenay, Piotr

2013-08-27T23:59:59.000Z

234

Supercritical Fluid Assisted Synthesis and Processing of Carbon Nanotubes  

Science Conference Proceedings (OSTI)

Carbon nanotubes (CNTs) constitute one of the most fascinating nanomaterials with specific properties and enormous applications. Taking advantages of the unique properties of supercritical fluids (SCFs), various techniques have been developed to produce and process CNTs and related nanostructured materials when conventional techniques become unviable. Herein we propose a critical review of these SCF based techniques. The most relevant characteristics of each technique and the enabled novel structures and functions which are difficult to accomplish by traditional techniques are highlighted.

Ye, Sufang; Wu, Fengming; Ye, Xiangrong; Lin, Yuehe

2009-03-26T23:59:59.000Z

235

Carbon nanotubes and other fullerenes produced from tire powder injected into an electric arc  

Science Conference Proceedings (OSTI)

A novel method of growing multiwall carbon nanotubes by injecting tire powder into an electric arc has been developed. The process is optimized using a DC electric arc in pressurized helium. The multiwall carbon nanotube product and the optimization process are characterized by transmission electron microscopy.

Murr, L.E. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States)]. E-mail: fekberg@utep.edu; Brown, D.K. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Esquivel, E.V. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Ponda, T.D. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Martinez, F. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States); Virgen, A. [Department of Metallurgical and Materials Engineering, University of Texas at El Paso, El Paso, TX 79968 (United States)

2005-11-15T23:59:59.000Z

236

Finite Element Modelling and Molecular Dynamic Simulations of Carbon nanotubes/ Polymer Composites  

E-Print Network (OSTI)

Modeling of single-walled carbon nanotubes, multi-walled nanotubes and nanotube reinforced polymer composites using both the Finite Element method and the Molecular Dynamic simulation technique is presented. Nanotubes subjected to mechanical loading have been analyzed. Elastic moduli and thermal coefficient of expansion are calculated and their variation with diameter and length is investigated. In particular, the nanotubes are modeled using 3D elastic beam finite elements with six degrees of freedom at each node. The difficulty in modeling multi walled nanotubes is the van der Waal's forces between adjacent layers which are geometrically non linear in nature. These forces are modeled using truss elements. The nanotube-polymer interface in a nano-composite is modeled on a similar basis. While performing the molecular dynamic simulations, the geometric optimization is performed initially to obtain the minimized configuration and then the desired temperature is attained by rescaling the velocities of carbon atoms in the nanotube. Results show that the Young's modulus increases with tube diameter in molecular mechanics whereas decreases in molecular dynamics since the inter-atomic potential due to chemical reactions between the atoms is taken into consideration in molecular dynamics unlike in molecular mechanics.

Gaddamanugu, Dhatri

2009-05-01T23:59:59.000Z

237

Exploration of artificial neural network to predict morphology of TiO2 nanotube  

Science Conference Proceedings (OSTI)

Artificial neural network (ANN) was developed to predict the morphology of TiO"2 nanotube prepared by anodization. The collected experimental data was simplified in an innovative approach and used as training and validation data, and the morphology of ... Keywords: Anodization, Artificial neural network, Morphology, Prediction, TiO2 nanotube

Hongyi Zhang; Jianling Zhao; Yuying Jia; Xuewen Xu; Cencun Tang; Yangxian Li

2012-03-01T23:59:59.000Z

238

Conducting Polymer Nanotubes toward Supercapacitor Ran Liu and Sang Bok Lee*  

E-Print Network (OSTI)

Conducting Polymer Nanotubes toward Supercapacitor Ran Liu and Sang Bok Lee* Capacitive properties density, power density values of the supercapacitors. Under the same charge- discharge current densities (5mA/cm2) and equal scan rate of cyclic voltammogram (CV, 100mV/s), nanotube supercapacitors

Rubloff, Gary W.

239

Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue  

E-Print Network (OSTI)

Graphene coating makes carbon nanotube aerogels superelastic and resistant to fatigue Kyu Hun Kim-based foams10­14 and aero- gels15,16 . However, all nanotube-based foams and aerogels devel- oped so far10,11,13,14 when they are subjected to cyclic strain. Here, we show that an inelastic aerogel made

Islam, Mohammad F.

240

Resistive analysis of mixed carbon nanotube bundle interconnect and its comparison with copper interconnect  

Science Conference Proceedings (OSTI)

As resistivity of Copper (Cu) increases with technology scaling, this drives us to look for new interconnect material for future very large scale integration (VLSI). Mixed carbon nanotube (CNT) bundle has superior properties like current carrying capacity ... Keywords: copper, interconnect, mixed carbon nanotube bundle

T. Alam; R. Dhiman; R. Chandel

2011-02-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Enhanced Photovoltaic Performance of Nanostructured Hybrid Solar Cell Using Highly Oriented TiO2 Nanotubes  

E-Print Network (OSTI)

Enhanced Photovoltaic Performance of Nanostructured Hybrid Solar Cell Using Highly Oriented TiO2 nanotubes can be effectively controlled for the suitable use for a hybrid solar cell by varying the diameter nanotubes to form hybrid solar cells. The open circuit voltage, short circuit current density, fill factor

Cao, Guozhong

242

Highly dispersed carbon nanotubes in organic media for polymer:fullerene photovoltaic devices  

E-Print Network (OSTI)

Highly dispersed carbon nanotubes in organic media for polymer:fullerene photovoltaic devices Gwang photovoltaic device are fabricated using homogeneously dispersed carbon nanotubes (CNTs) in a polymer and by the fabrica- tion of an organic thin film transistor. An organic solar cell was fabricated from these com

Hong, Soon Hyung

243

MD Study of Phase Change of Water inside a Carbon Nanotube Tatsuto KIMURA and Shigeo MARUYAMA  

E-Print Network (OSTI)

into ice crystal at 220 K or 200 K. In the case of phase change at 220 K, octagonal ice nanotube MD Study of Phase Change of Water inside a Carbon Nanotube * Tatsuto KIMURA and Shigeo MARUYAMA Dept. of Mech. Eng., The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 Phase change

Maruyama, Shigeo

244

Molecular Dynamics Study of Phase Change of Water inside a Single-Walled Carbon Nanotube  

E-Print Network (OSTI)

The phase change of liquid water to ice crystal inside a single-walled carbon nanotube (SWNT) was studiedMolecular Dynamics Study of Phase Change of Water inside a Single-Walled Carbon Nanotube Shigeo phase change for various cooling rates in a SWNT with various chiralities were examined. With certain

Maruyama, Shigeo

245

Improved field emission characteristic of carbon nanotubes by an Ag micro-particle intermediation layer  

Science Conference Proceedings (OSTI)

An efficient way to improve field emission characteristic of carbon nanotubes (CNTs) through an Ag micro-particle intermediation layer is presented. In this way, the intermediation layer is deposited on an indium tin oxide glass substrate by electrochemical ... Keywords: Ag micro-particle intermediation layer, Carbon nanotubes, Field emission

Wenhui Lu; Hang Song; Yixin Jin; Haifeng Zhao; Zhiming Li; Hong Jiang; Guoqing Miao

2008-05-01T23:59:59.000Z

246

Comparison of quantum mechanical methods for the simulation of electronic transport through carbon nanotubes  

Science Conference Proceedings (OSTI)

In the present work we study the electronic transport properties of finite length single-wall carbon nanotubes (CNTs) by comparing three different theoretical frameworks. A simple model is used to describe the electrodes and the way they are attached ... Keywords: Carbon nanotube, Density functional theory, Electronic transport, Extended Hückel theory, Greens's function, Tight-binding

Andreas Zienert, JöRg Schuster, Thomas Gessner

2013-06-01T23:59:59.000Z

247

Carbon nanotube field effect transistors for high performance analog applications: An optimum design approach  

Science Conference Proceedings (OSTI)

There is a need to explore circuit designs in new emerging technologies for their rapid commercialization to extend Moore's law beyond 22nm technology node. Carbon nanotube based transistor (CNFET) has significant potential to replace CMOS in the future ... Keywords: Analog, CMOS, Carbon nanotube field effect transistor (CNFET), Chirality, Single walled CNT

Fahad Ali Usmani; Mohammad Hasan

2010-07-01T23:59:59.000Z

248

Novel attributes in scaling issues of carbon nanotube field-effect transistors  

Science Conference Proceedings (OSTI)

For the first time, we present a scaling study of carbon nanotube field-effect transistors (CNTFETs) using a two-dimensional model. We investigate the scaling issues in device performance focusing on transconductance characteristics, output characteristics, ... Keywords: CNTFET, Capacitance model, Carbon nanotube diameter, Gate oxide thickness

Zahra Arefinia; Ali A. Orouji

2009-01-01T23:59:59.000Z

249

A simple and versatile micro contact printing method for generating carbon nanotubes patterns on various substrates  

Science Conference Proceedings (OSTI)

We present an optimized process for generating at low cost, patterns of carbon nanotubes (CNTs) on a large variety of substrates through a simple micro contact printing method. This method meets the requirements for the integration of CNTs into microdevices, ... Keywords: Carbon nanotubes, Flexible electronics, Micro-patterning, Soft-lithography, Spray-coating

A. BéDuer; F. Seichepine; E. Flahaut; C. Vieu

2012-09-01T23:59:59.000Z

250

Resonance Raman Study of I2 -Intercalated Single-Walled Carbon Nanotubes  

Science Conference Proceedings (OSTI)

We conducted resonance Raman studies on the iodine-intercalated bundles of single-walled carbon nanotubes (SWNTs). The Raman spectra obtained using the 647.1-nm line of a Kr-ion laser indicate that I2 intercalation affects the electronic ... Keywords: I $_2$-intercalation, Raman spectroscopy, resonance Raman, single-walled carbon nanotubes

V. M. Nguyen; I. S. Yang; Y. Jung; S. -J. Kim; J. Oh; W. Yi

2007-01-01T23:59:59.000Z

251

Photovoltaic device using single wall carbon nanotubes and method of fabricating the same  

DOE Patents (OSTI)

A photovoltaic device and methods for forming the same. In one embodiment, the photovoltaic device has a silicon substrate, and a film comprising a plurality of single wall carbon nanotubes disposed on the silicon substrate, wherein the plurality of single wall carbon nanotubes forms a plurality of heterojunctions with the silicon in the substrate.

Biris, Alexandru S.; Li, Zhongrui

2012-11-06T23:59:59.000Z

252

Modeling of carbon nanotube field-effect transistor with nanowelding treatment  

Science Conference Proceedings (OSTI)

An efficient and universal numerical model of carbon nanotube (CN) field-effect transistor (FET) with nanowelding treatment has been developed. In this model, an analytic expression of carrier distribution of intrinsic CN is incorporated into the modified ... Keywords: 73.63.Fg, 85.35.Kt, Ambipolar conduction, Carbon nanotube field-effect transistor (CNFET), Newton-Raphson iteration, Schottky barrier (SB)

Wei Zhang; Changxin Chen; Yafei Zhang

2009-12-01T23:59:59.000Z

253

Photovoltaic properties of multi-walled carbon nanotubes deposited on n-doped silicon  

Science Conference Proceedings (OSTI)

Multi-wall carbon nanotubes (MWCNTs), grown by catalytic chemical vapor deposition (CCVD) over Fe supported on alumina catalyst, using isobutane as feedstock, are dispersed in aqueous solutions of sodium dodecyl sulfate. Stable and highly photosensitive ... Keywords: Hybrid solar cells, Multi-walled carbon nanotubes, Silicon heterojunctions

A. Arena; N. Donato; G. Saitta; S. Galvagno; C. Milone; A. Pistone

2008-12-01T23:59:59.000Z

254

The effects of atmospheric pressure plasma on the synthesis of carbon nanotubes  

Science Conference Proceedings (OSTI)

In this study, we investigated the effects of atmospheric plasma on the synthesis of carbon nanotubes (CNTs) forests. Tall and high CNTs forests have been successfully grown on a large scale using a newly developed system called atmospheric pressure ... Keywords: Atmospheric pressure, Carbon nanotubes, Mass production, Plasma effects, Plasma enhanced chemical vapor deposition

Seok Seung Shin; Bum Ho Choi; Young Mi Kim; Jong Ho Lee; Dong Chan Shin

2009-04-01T23:59:59.000Z

255

Carbon nanotube vertical membranes for electrostatically actuated micro-electro-mechanical devices  

Science Conference Proceedings (OSTI)

In this work, we investigate vertically aligned carbon nanotube (CNT) membranes as building blocks to realize electrostatically actuated micro-electro-mechanical-systems (MEMS). The fabricated CNT dense arrays are grown on adjacent metal electrodes and ... Keywords: Capacitors, Carbon nanotube, MEMS, Membrane, NEMS, Vertically aligned

A. Arun; D. Acquaviva; M. Fernández-Bolaños; P. Salet; H. Le-Poche; P. Pantigny; T. Idda; A. M. Ionescu

2010-05-01T23:59:59.000Z

256

Preparation and Thermal Characterization of Carbon Nanotubes-Based Composites for Applications in Electronics Packaging  

Science Conference Proceedings (OSTI)

The thermal resistance of nanocomposite layers formed by Single Wall Carbon Nanotubes (SWCNT) dispersed in epoxy resins has been measured under conditions similar to the ones used to dissipate heat in microelettronic devices. Thevariation of thermal ... Keywords: Carbon Nanotubes, Thermal Management, Epoxy Resin, Nanocomposite, TIM, Thermal Interface Materials

Francesco Toschi; Emanuela Tamburri; Valeria Guglielmotti; Maria Letizia Terranova; Andrea Reale; Aldo Di Carlo; Daniele Passeri; Marco Rossi; Carlo Falessi; Annamaria Fiorello; Roberta Buttiglione

2008-02-01T23:59:59.000Z

257

The design of a low power carbon nanotube chemical sensor system  

Science Conference Proceedings (OSTI)

This paper presents a hybrid CNT/CMOS chemical sensor system that comprises of a carbon nanotube sensor array and a CMOS interface chip. The full system, including the sensor, consumes 32?W at 1.83kS/s readout rate, accomplished through ... Keywords: carbon nanotube, low power, sensor system

Taeg Sang Cho; Kyeong-jae Lee; Jing Kong; Anantha P. Chandrakasan

2008-06-01T23:59:59.000Z

258

Fabrication of single electron transistors in multi-wall carbon nanotubes using Ar beam irradiation  

Science Conference Proceedings (OSTI)

The Ar beam with an acceleration voltage of 300 V has been irradiated to multi-wall carbon nanotubes (MWNTs) through a narrow opening of the resist, in order to form a tunnel barrier. The tunnel resistance could be set by appropriate dose, in the range ... Keywords: Ar beam, carbon nanotubes, coulomb blockade, quantum dots, single electron transistor

K. Ishibashi; M. Suzuki; D. Tsuya; Y. Aoyagi

2003-06-01T23:59:59.000Z

259

Semi-analytical model for schottky-barrier carbon nanotube and graphene nanoribbon transistors  

Science Conference Proceedings (OSTI)

This paper describes a physics-based semi-analytical model for Schottky-barrier carbon nanotube (CNT) and graphene nanoribbon (GNR) transistors. The model includes the treatment of (i) both tunneling and thermionic currents, (ii) ambipolar conduction, ... Keywords: carbon nanotubes, graphene nanoribbons, models, schottky-barrier

Xuebei Yang; Gianluca Fiori; Giuseppe Iannaccone; Kartik Mohanram

2010-05-01T23:59:59.000Z

260

Poster CATALYST SULPHUR ADDITIVES IN THE GROWTH OF CARBON NANOTUBES  

E-Print Network (OSTI)

Scientific community have recently focused especial attention on carbon nanomaterials, specially on carbon nanotubes (CNTs), because of their fascinating physical properties and potential applications [1]. Some of these applications, such as gas and energy storage, require high yields of well-defined qualities, what makes Chemical Vapor Deposition (CVD) one of the most appropriate methods for the synthesis of carbon nanotubes as it is easily scalable and makes the synthesis economically available. CVD is a versatile and promising method for CNTs synthesis as it offers the possibility of controlling a high yield synthesis of carbon nanotubes (CNTs) with specific properties by only controlling the different parameters taking place in the furnace during the hydrocarbon feedstock decomposition over a metal catalyst [2]. This communication explores the growth of CNTs by chemical vapor deposition (CVD) from methane decomposition over different catalysts prepared by the sol-gel technique, using MgO as support [3, 4] and varying the transition metal (active element in the catalyst). The aim of this work is to study the influence of additives, especially sulphur in different forms, on the activity of this kind of supported catalysts and how do the yield, morphology and physical

C. Vallés; M. Pérez-mendoza; G. Legac; W. K. Maser; M. T. Martínez; A. M. Benito

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Hypergolic fuel detection using individual single walled carbon nanotube networks  

SciTech Connect

Accurate and reliable detection of hypergolic fuels such as hydrazine (N{sub 2}H{sub 4}) and its derivatives is vital to missile defense, aviation, homeland security, and the chemical industry. More importantly these sensors need to be capable of operation at low temperatures (below room temperature) as most of the widely used chemical sensors operate at high temperatures (above 300 deg. C). In this research a simple and highly sensitive single walled carbon nanotube (SWNT) network sensor was developed for real time monitoring of hydrazine leaks to concentrations at parts per million levels. Upon exposure to hydrazine vapor, the resistance of the air exposed nanotubes (p-type) is observed to increase rapidly while that of the vacuum-degassed nanotubes (n-type) is observed to decrease. It was found that the resistance of the sample can be recovered through vacuum pumping and exposure to ultraviolet light. The experimental results support the electrochemical charge transfer mechanism between the oxygen redox couple of the ambient and the Fermi level of the SWNT. Theoretical results of the hydrazine-SWNT interaction are compared with the experimental observations. It was found that a monolayer of water molecules on the SWNT is necessary to induce strong interactions between hydrazine and the SWNT by way of introducing new occupied states near the bottom of the conduction band of the SWNT.

Desai, S. C.; Willitsford, A. H. [Department of Electrical and Computer Engineering, University of Louisville, Louisville, Kentucky 40292 (United States); Sumanasekera, G. U. [Department of Electrical and Computer Engineering, University of Louisville, Louisville, Kentucky 40292 (United States); Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292 (United States); Yu, M.; Jayanthi, C. S.; Wu, S. Y. [Department of Physics and Astronomy, University of Louisville, Louisville, Kentucky 40292 (United States); Tian, W. Q. [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023 (China)

2010-06-15T23:59:59.000Z

262

Laser irradiation of carbon nanotube films: Effects and heat dissipation probed by Raman spectroscopy  

Science Conference Proceedings (OSTI)

We investigate the thermal properties of thin films formed by single- and multi-walled carbon nanotubes submitted to laser irradiation using Raman scattering as a probe of both the tube morphology and the local temperature. The nanotubes were submitted to heating/cooling cycles attaining high laser intensities ({approx}1.4 MW/cm{sup 2}) under vacuum and in the presence of an atmosphere, with and without oxygen. We investigate the heat diffusion of the irradiated nanotubes to their surroundings and the effect of laser annealing on their properties. The presence of oxygen during laser irradiation gives rise to an irreversible increase of the Raman efficiency of the carbon nanotubes and to a remarkable increase of the thermal conductivity of multi-walled films. The second effect can be applied to design thermal conductive channels in devices based on carbon nanotube films using laser beams.

Mialichi, J. R.; Brasil, M. J. S. P.; Iikawa, F. [Instituto de Fisica 'Gleb Wataghin,' Unicamp, Campinas, 13083-859 Sao Paulo (Brazil); Verissimo, C.; Moshkalev, S. A. [Centro de Componentes Semicondutores, Unicamp, Campinas, 13083-870 Sao Paulo (Brazil)

2013-07-14T23:59:59.000Z

263

A High-Flux, Flexible Membrane with Parylene-encapsulated Carbon Nanotubes  

Science Conference Proceedings (OSTI)

We present fabrication and characterization of a membrane based on carbon nanotubes (CNTs) and parylene. Carbon nanotubes have shown orders of magnitude enhancement in gas and water permeability compared to estimates generated by conventional theories [1, 2]. Large area membranes that exhibit flux enhancement characteristics of carbon nanotubes may provide an economical solution to a variety of technologies including water desalination [3] and gas sequestration [4]. We report a novel method of making carbon nanotube-based, robust membranes with large areas. A vertically aligned dense carbon nanotube array is infiltrated with parylene. Parylene polymer creates a pinhole free transparent film by exhibiting high surface conformity and excellent crevice penetration. Using this moisture-, chemical- and solvent-resistant polymer creates carbon nanotube membranes that promise to exhibit high stability and biocompatibility. CNT membranes are formed by releasing a free-standing film that consists of parylene-infiltrated CNTs, followed by CNT uncapping on both sides of the composite material. Thus fabricated membranes show flexibility and ductility due to the parylene matrix material, as well as high permeability attributed to embedded carbon nanotubes. These membranes have a potential for applications that may require high flux, flexibility and durability.

Park, H G; In, J; Kim, S; Fornasiero, F; Holt, J K; Grigoropoulos, C P; Noy, A; Bakajin, O

2008-03-14T23:59:59.000Z

264

Field Ionization of Cold Atoms near the Wall of a Single Carbon Nanotube  

E-Print Network (OSTI)

We observe the capture and field ionization of individual atoms near the side wall of a single suspended nanotube. Extremely large cross sections for ionization from an atomic beam are observed at modest voltages due to the nanotube's small radius and extended length. The effects of the field strength on both the atomic capture and the ionization process are clearly distinguished in the data, as are prompt and delayed ionizations related to the locations at which they occur. Efficient and sensitive neutral atom detectors can be based on the nanotube capture and wall ionization processes.

Anne Goodsell; Trygve Ristroph; J. A. Golovchenko; Lene Vestergaard Hau

2010-04-15T23:59:59.000Z

265

Bending of metal-filled carbon nanotube under electron beam irradiation  

Science Conference Proceedings (OSTI)

Electron beam irradiation induced, bending of Iron filled, multiwalled carbon nanotubes is reported. Bending of both the carbon nanotube and the Iron contained within the core was achieved using two approaches with the aid of a high resolution electron microscope (HRTEM). In the first approach, bending of the nanotube structure results in response to the irradiation of a pristine kink defect site, while in the second approach, disordered sites induce bending by focusing the electron beam on the graphite walls. The HRTEM based in situ observations demonstrate the potential for using electron beam irradiation to investigate and manipulate the physical properties of confined nanoscale structures.

Misra, Abha [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore, Karnataka, 560012 (India)

2012-03-15T23:59:59.000Z

266

Plasma stabilisation of metallic nanoparticles on silicon for the growth of carbon nanotubes  

SciTech Connect

Ammonia (NH{sub 3}) plasma pretreatment is used to form and temporarily reduce the mobility of Ni, Co, or Fe nanoparticles on boron-doped mono- and poly-crystalline silicon. X-ray photoemission spectroscopy proves that NH{sub 3} plasma nitrides the Si supports during nanoparticle formation which prevents excessive nanoparticle sintering/diffusion into the bulk of Si during carbon nanotube growth by chemical vapour deposition. The nitridation of Si thus leads to nanotube vertical alignment and the growth of nanotube forests by root growth mechanism.

Esconjauregui, S.; Fouquet, M.; Bayer, B. C.; Gamalski, A. D.; Chen Bingan; Xie Rongsi; Hofmann, S.; Robertson, J. [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Cepek, C.; Bhardwaj, S. [Istituto Officina dei Materiali-CNR, Laboratorio TASC, s.s. 14 km 163.5, I-34149 Trieste (Italy); Ducati, C. [Department of Materials Science and Metallurgy, University of Cambridge, Cambridge CB2 3QZ (United Kingdom)

2012-08-01T23:59:59.000Z

267

Hot wire production of single-wall and multi-wall carbon nanotubes  

DOE Patents (OSTI)

Apparatus (210) for producing a multi-wall carbon nanotube (213) may comprise a process chamber (216), a furnace (217) operatively associated with the process chamber (216), and at least one filament (218) positioned within the process chamber (216). At least one power supply (220) operatively associated with the at least one filament (218) heats the at least one filament (218) to a process temperature. A gaseous carbon precursor material (214) operatively associated with the process chamber (216) provides carbon for forming the multi-wall carbon nanotube (213). A metal catalyst material (224) operatively associated with the process (216) catalyzes the formation of the multi-wall carbon nanotube (213).

Dillon, Anne C. (Boulder, CO); Mahan, Archie H. (Golden, CO); Alleman, Jeffrey L. (Lakewood, CO)

2010-10-26T23:59:59.000Z

268

Polymer-assisted deposition of films and preparation of carbon nanotube arrays using the films  

DOE Patents (OSTI)

Carbon nanotubes were prepared by coating a substrate with a coating solution including a suitable solvent, a soluble polymer, a metal precursor having a first metal selected from iron, nickel, cobalt, and molybdenum, and optionally a second metal selected from aluminum and magnesium, and also a binding agent that forms a complex with the first metal and a complex with the second metal. The coated substrate was exposed to a reducing atmosphere at elevated temperature, and then to a hydrocarbon in the reducing atmosphere. The result was decomposition of the polymer and formation of carbon nanotubes on the substrate. The carbon nanotubes were often in the form of an array on the substrate.

Luo, Hongmei; Li, Qingwen; Bauer, Eve; Burrell, Anthony Keiran; McCleskey, Thomas Mark; Jia, Quanxi

2013-07-16T23:59:59.000Z

269

Array of aligned and dispersed carbon nanotubes and method of producing the array  

DOE Patents (OSTI)

An array of aligned and dispersed carbon nanotubes includes an elongate drawn body including a plurality of channels extending therethrough from a first end to a second end of the body, where the channels have a number density of at least about 100,000 channels/mm.sup.2 over a transverse cross-section of the body. A plurality of carbon nanotubes are disposed in each channel, and the carbon nanotubes are sufficiently dispersed and aligned along a length of the channels for the array to comprise an average resistivity per channel of about 9700 .OMEGA.m or less.

Ivanov, Ilia N; Simpson, John T; Hendricks, Troy R

2013-06-11T23:59:59.000Z

270

Array of aligned and dispersed carbon nanotubes and method of producing the array  

DOE Patents (OSTI)

An array of aligned and dispersed carbon nanotubes includes an elongate drawn body including a plurality of channels extending therethrough from a first end to a second end of the body, where the channels have a number density of at least about 100,000 channels/mm.sup.2 over a transverse cross-section of the body. A plurality of carbon nanotubes are disposed in each channel, and the carbon nanotubes are sufficiently dispersed and aligned along a length of the channels for the array to comprise an average resistivity per channel of about 9700 .OMEGA.m or less.

Ivanov, Ilia N. (Knoxville, TN); Simpson, John T. (Clinton, TN); Hendricks, Troy R. (Knoxville, TN)

2012-06-19T23:59:59.000Z

271

Understanding the mechanism of nanotube synthesis for controlled production of specific (n,m) structures  

Science Conference Proceedings (OSTI)

This report shows the extensive research on the mechanism responsible for the formation of single walled carbon nanotubes in order to get control over their structural parameters (diameter and chirality). Catalyst formulations, pre-treatment conditions, and reaction conditions are described in detail as well as mechanisms to produce nanotubes structures of specific arrays (vertical forest, nanotube pillars). Applications of SWNT in different fields are also described in this report. In relation to this project five students have graduated (3 PhD and 2 MS) and 35 papers have been published.

Resasco, Daniel E.

2010-02-11T23:59:59.000Z

272

Separation of carbon nanotubes into chirally enriched fractions  

DOE Patents (OSTI)

A mixture of single-walled carbon nanotubes ("SWNTs") is separated into fractions of enriched chirality by preparing an aqueous suspension of a mixture of SWNTs and a surfactant, injecting a portion of the suspension on a column of separation medium having a density gradient, and centrifuging the column. In some embodiments, salt is added prior to centrifugation. In other embodiments, the centrifugation is performed at a temperature below room temperature. Fractions separate as colored bands in the column. The diameter of the separated SWNTs decreases with increasing density along the gradient of the column. The colored bands can be withdrawn separately from the column.

Doorn, Stephen K. (Los Alamos, NM); Niyogi, Sandip (Los Alamos, NM)

2012-04-10T23:59:59.000Z

273

Nanovision: Nanotubes, Nanowires, and Nanoparticles (404th Brookhaven Lecture)  

DOE Green Energy (OSTI)

A very few years ago, the field of nanoscience — the science of materials at the nanometer (nm), or billionth-of-a-meter scale — was relatively unexplored. Today, it is one of the hottest areas of research, with new techniques and new tools to probe the structure and function of materials at the atomic and molecular level. Once scientists had found that, at this ultra-small scale, the chemical and physical properties of materials often differ from the properties they have in bulk form, the rush was on: first to determine the new structural and chemical characteristics of each material, then, to try and use this knowledge to improve products and processes needed in everyday life. Just some of the possible benefits from nanotechnology, for example, are better electronics, stronger and lighter materials, and more efficient catalysts to speed up chemical processes. Wong’s “nanovision,” as he will explain, emerges from how the study of carbon and non-carbon forms of materials at the nanoscale reveals different morphological structures: some are tiny tubes, others are like wires, and others are in particle form. These minute nanostructures yield different properties as they are treated in different ways. For example, if a carbon nanotube, which might be as small as 1.4 nm in diameter (a human hair is about 10,000 nm wide), is subjected to ozone, its sidewall structure becomes filled with holes, and the modified nanotube can thus be used for gas intercalation, critical for energy storage considerations.

Wong, Stanislaus (Materials Science)

2005-05-18T23:59:59.000Z

274

Polymer Grafted Janus Multi-Walled Carbon Nanotubes  

Science Conference Proceedings (OSTI)

We describe a novel and facile strategy to modify the surface of carbon nanotubes (CNTs) with two chemically different polymer brushes utilizing the grafting from technique. A [4 + 2] Diels Alder cycloaddition reaction was used to functionalize multi-walled carbon nanotubes (MWNTs) with two different precursor initiators, one for ring opening polymerization (ROP) and one for atom transfer radical polymerization (ATRP). The binary functionalized MWNTs were used for the simultaneous surface initiated polymerizations of different monomers resulting in polymer grafted MWNTs that can form Janus type structures under appropriate conditions. 1H NMR, FTIR and Raman spectra showed that the precursor initiators were successfully synthesized and covalently attached on the CNT surface. Thermogravimetric analysis (TGA) revealed that the grafted polymer content varies when different monomer ratios and polymerization times are used. The presence of an organic layer around the CNTs was observed through transmission electron microscopy (TEM). Differential scanning calorimetry (DSC) proved that the glass transition (Tg) and melting (Tm) temperatures of the grafted polymers are affected by the presence of the CNTs, while circular dichroism (CD) spectra indicated that the PLLA ahelix conformation remains intact.

Priftis, Dimitrios [ORNL; Sakellariou, Georgios [ORNL; Baskaran, Durairaj [University of Tennessee, Knoxville (UTK); Mays, Jimmy [ORNL; Hadjichristidis, Nikos [University of Athens, Athens, Greece

2009-01-01T23:59:59.000Z

275

Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF| U.S. DOE Office of Science  

Office of Science (SC) Website

Boron-Nitride (BN) Nanotubes (BNNT) at Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives Boron-Nitride (BN) Nanotubes (BNNT) at TJNAF Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: Boron-Nitride (BN) Nanotubes (BNNT) Developed at: Jefferson Lab Free Electron Facility Developed in: 2008-2011

276

Carbon Nanotubes and Nano-Structure Manufacturing at TJNAF | U.S. DOE  

Office of Science (SC) Website

Carbon Nanotubes and Nano-Structure Carbon Nanotubes and Nano-Structure Manufacturing at TJNAF Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Spinoff Applications Spinoff Archives SBIR/STTR Applications of Nuclear Science and Technology Funding Opportunities Nuclear Science Advisory Committee (NSAC) News & Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: sc.np@science.doe.gov More Information » Spinoff Archives Carbon Nanotubes and Nano-Structure Manufacturing at TJNAF Print Text Size: A A A RSS Feeds FeedbackShare Page Application/instrumentation: Carbon Nanotube & Nano-structure Manufacturing Developed at: Thomas Jefferson National Accelerator Laboratory

277

Fabrication and electrical characterization of transistors made from carbon nanotubes and graphene  

E-Print Network (OSTI)

Carbon nanotubes and graphene are low-dimensional allotropes of carbon which exhibit novel mechanical and electrical properties. The methods for producing these materials and fabricating electronic devices from them are ...

Nezich, Daniel Andrew

2010-01-01T23:59:59.000Z

278

Chemical, mechanical, and thermal control of substrate-bound carbon nanotube growth  

E-Print Network (OSTI)

Carbon nanotubes (CNTs) are long molecules having exceptional properties, including several times the strength of steel piano wire at one fourth the density, at least five times the thermal conductivity of pure copper, and ...

Hart, Anastasios John, 1979-

2006-01-01T23:59:59.000Z

279

Carbon nanotube synthesis and detection : limiting the environmental impact of novel technologies  

E-Print Network (OSTI)

Driven by commercial promise, the carbon nanotube (CNT) industry is growing rapidly, yet little is known about the potential environmental impacts of these novel materials. In particular, there are no methods to detect ...

Plata, Desirée L

2009-01-01T23:59:59.000Z

280

Nafion titania nanotubes nanocomposite electrolytes for high-temperature direct methanol fuel cells  

Science Conference Proceedings (OSTI)

Nafion-based nanocomposite membranes containing various amounts of titania nanotubes (TNTs) as an inorganic filler have been prepared using melt-mixing method and have been investigated for proton exchange membrane applications. The onedimensional TNTs ...

Nonhlanhla Precious Cele, Suprakas Sinha Ray, Lucky Sikhwivhilu

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Thermogravimetry-Mass Spectrometry for Carbon Nanotube Detection in Complex Mixtures  

E-Print Network (OSTI)

In spite of the growth of the carbon nanotube (CNT) industry, there are no established analytical methods with which to detect or quantify CNTs in environmental matrices. Given that CNTs have relatively high thermal ...

Plata, Desiree Louise

282

Characterization and hydrogen storage of surface-modified multiwalled carbon nanotubes for fuel cell application  

Science Conference Proceedings (OSTI)

The synthesis, identification, and H2 storage of multiwalled carbon nanotubes (MWCNTs) have been investigated in the present work. MWCNTs were produced from the catalytic-assembly solvent (benzene)-thermal (solvothermal) route. Reduction of ...

Kuen-Song Lin, Yao-Jen Mai, Shin-Rung Li, Chia-Wei Shu, Chieh-Hung Wang

2012-01-01T23:59:59.000Z

283

Biogenic formation of photoactive arsenic-sulfide nanotubes by Shewanella sp. strain HN-41  

SciTech Connect

Microorganisms facilitate the formation of a wide range of minerals that have unique physical and chemical properties as well as morphologies that are not produced by abiotic processes. Here, we report the production of an extensive extracellular network of filamentous, arsenic-sulfide (As-S) nanotubes (20–100 nm in diameter by 30 µm in length) by the dissimilatory metal-reducing bacterium Shewanella sp. HN-41. The As-S nanotubes, formed via the reduction of As(V) and S2O, were initially amorphous As2S3 but evolved with increasing incubation time toward polycrystalline phases of the chalcogenide minerals realgar (AsS) and duranusite (As4S). Upon maturation, the As-S nanotubes behaved as metals and semiconductors in terms of their electrical and photoconductive properties, respectively. The As-S nanotubes produced by Shewanella may provide useful materials for novel nano- and opto-electronic devices.

Lee, Ji-Hoon; Kim, Min-Gyu; Yoo, Bongyoung; Myung, Nosang V.; Maeng, Jongsun; Lee, Takhe; Dohnalkova, Alice; Fredrickson, Jim K.; Sadowsky, Michael J.; Hur, Hor-Gil

2007-12-18T23:59:59.000Z

284

Understanding and engineering interfacial charge transfer of carbon nanotubes and graphene for energy and sensing applications  

E-Print Network (OSTI)

Graphene is a one-atom thick planar monolayer of sp2 -bonded carbon atoms organized in a hexagonal crystal lattice. A single walled carbon nanotube (SWCNT) can be thought of as a graphene sheet rolled up into a seamless ...

Paulus, Geraldine L. C. (Geraldine Laura Caroline)

2013-01-01T23:59:59.000Z

285

Fracture toughness of carbon nanotube-reinforced metal- and ceramic-matrix composites  

Science Conference Proceedings (OSTI)

Hierarchical analysis of the fracture toughness enhancement of carbon nanotube- (CNT-) reinforced hard matrix composites is carried out on the basis of shear-lag theory and facture mechanics. It is found that stronger CNT/matrix interfaces cannot definitely ...

Y. L. Chen; B. Liu; Y. Huang; K. C. Hwang

2011-01-01T23:59:59.000Z

286

Polymer and carbon nanotube materials for chemical sensors and organic electronics  

E-Print Network (OSTI)

This thesis details the development of new materials for high-performance chemical sensing as well as organic electronic applications. In Chapter 2, we develop a chemiresistive material based on single-walled carbon nanotubes ...

Wang, Fei, Ph. D. Massachusetts Institute of Technology

2010-01-01T23:59:59.000Z

287

NANOTECHNOLOGY LAW & BUSINESS MARCH 2007 585 Carbon Nanotube-Based Supercapacitors  

E-Print Network (OSTI)

NANOTECHNOLOGY LAW & BUSINESS · MARCH 2007 585 Carbon Nanotube-Based Supercapacitors: Technologies-layer capacitors (also known as "supercapacitors" or "ultracapacitors") have tremendous potential as high double layer (ECDL) capacitors (also abbreviated EDLC), commonly called "supercapacitors

Bennett, Gisele

288

Highly Ordered TiO2 Nanotube Arrays with Novel Arrangements by ...  

Science Conference Proceedings (OSTI)

Aerosol Jet® Material Deposition for High Resolution Printed Electronic Applications ... Carbon Nanotube Coatings Laser Power and Energy Measurements ... Rational Tailoring of 1-D (Nanowires), 2-D (Graphene) and 3-D (Ceramic/Carbon ...

289

Thermal Conduction in Aligned Carbon Nanotube–Polymer Nanocomposites with High Packing Density  

E-Print Network (OSTI)

Nanostructured composites containing aligned carbon nanotubes (CNTs) are very promising as interface materials for electronic systems and thermoelectric power generators. We report the first data for the thermal conductivity ...

Marconnet, Amy M.

290

Acoustic energy dissipation and thermalization in carbon nanotubes: Atomistic modeling and mesoscopic description  

E-Print Network (OSTI)

The exchange of energy between low-frequency mechanical oscillations and high-frequency vibrational modes in carbon nanotubes (CNTs) is a process that plays an important role in a range of dynamic phenomena involving the ...

Nicholson, David A.

291

Design of electrode for electrochemical energy storage and conversion devices using multiwall carbon nanotubes  

E-Print Network (OSTI)

All-multiwall carbon nanotube (MWNT) thin films are created by layer-by-layer (LbL) assembly of surface functionalized MWNTs. Negatively and positively charged MWNTs were prepared by surface functionalization, allowing the ...

Lee, Seung Woo, Ph. D. Massachusetts Institute of Technology

2010-01-01T23:59:59.000Z

292

System level performance analysis of carbon nanotube global interconnects for emerging chip multiprocessors  

Science Conference Proceedings (OSTI)

Although carbon nanotubes (CNTs) have been widely proposed as interconnect fabrics for future ultra deep submicron (UDSM) technologies, there is a lack of system-level performance analysis using these interconnects. In this paper, we investigate the ...

Sudeep Pasricha; Fadi Kurdahi; Nikil Dutt

2008-06-01T23:59:59.000Z

293

Adsorption sites of hydrogen atom on pure and Mg-doped multi-walled carbon nanotubes  

Science Conference Proceedings (OSTI)

Hydrogen adsorption sites on pure multiwalled carbon nanotube (MWCNT) and Mg-doped MWCNTs material system have been investigated using molecular dynamics (MD) simulations as well as quantum chemical calculations. Through combining MWCNTs with Mg, the ...

A. A. Al-Ghamdi, E. Shalaan, F. S. Al-Hazmi, Adel S. Faidah, S. Al-Heniti, M. Husain

2012-01-01T23:59:59.000Z

294

Raman spectroscopy study of heat-treated and boron-doped double wall carbon nanotubes  

E-Print Network (OSTI)

We performed Raman spectroscopy experiments on undoped and boron-doped double walled carbon nanotubes (DWNTs) that exhibit the “coalescence inducing mode” as these DWNTs are heat treated to temperatures between 1200 °C ...

Villalpando Paez, Federico

295

Detecting Lyme Disease Using Antibody-Functionalized Single-Walled Carbon Nanotube Transistors  

E-Print Network (OSTI)

We examined the potential of antibody-functionalized single-walled carbon nanotube (SWNT) field-effect transistors (FETs) for use as a fast and accurate sensor for a Lyme disease antigen. Biosensors were fabricated on oxidized silicon wafers using chemical vapor deposition grown carbon nanotubes that were functionalized using diazonium salts. Attachment of Borrelia burgdorferi (Lyme) flagellar antibodies to the nanotubes was verified by Atomic Force Microscopy and electronic measurements. A reproducible shift in the turn-off voltage of the semiconducting SWNT FETs was seen upon incubation with Borrelia burgdorferi flagellar antigen, indicative of the nanotube FET being locally gated by the residues of flagellar protein bound to the antibody. This sensor effectively detected antigen in buffer at concentrations as low as 1 ng/ml, and the response varied strongly over a concentration range coinciding with levels of clinical interest. Generalizable binding chemistry gives this biosensing platform the potential to...

Lerner, Mitchell B; Goldsmith, Brett R; Brisson, Dustin; Johnson, A T Charlie

2013-01-01T23:59:59.000Z

296

Experimental observation and quantum modeling of electron irradiation on single-wall carbon nanotubes  

Science Conference Proceedings (OSTI)

In situ experiments, based on electron irradiation at high temperature in a transmission electron microscope, are used to investigate isolated, packed and crossing single-wall nanotubes. During continuous, uniform atom removal, surfaces of isolated single-wall ...

J. -C. Charlier; M. Terrones; F. Banhart; N. Grobert; H. Terrones; P. M. Ajayan

2003-12-01T23:59:59.000Z

297

Polyacrylonitrile/carbon nanotube composite fibers: reinforcement efficiency and carbonization studies .  

E-Print Network (OSTI)

??Polyacrylonitrile (PAN)/carbon nanotube (CNT) composite fibers were made using various processing methods such as conventional solution spinning, gel spinning, and bi-component gel spinning. The detailed… (more)

Chae, Han Gi

2008-01-01T23:59:59.000Z

298

Multiscale hybrid micro-nanocomposites based on carbon nanotubes and carbon fibers  

Science Conference Proceedings (OSTI)

Amino-modified double wall carbon nanotube (DWCNT-NH2)/carbon fiber (CF)/epoxy hybrid micro-nanocomposite laminates were prepared by a resin infusion technique. DWCNT-NH2/epoxy nanocomposites and carbon fiber/epoxy microcomposites ...

Fawad Inam; Doris W. Y. Wong; Manabu Kuwata; Ton Peijs

2010-01-01T23:59:59.000Z

299

Radiation Detection: Resistivity Responses in Functional Poly(Olefin Sulfone)/Carbon Nanotube Composites  

E-Print Network (OSTI)

Detection of gamma rays is shown using a non-scintillating organic-based sensor composed of poly(olefin sulfone)/carbon nanotube blends. Functionalization of the polymers can be performed after polymerization to tailor ...

Swager, Timothy Manning

300

Investigation of lithium-air battery discharge product formed on carbon nanotube and nanofiber electrodes  

E-Print Network (OSTI)

Carbon nanotubes have been actively investigated for integration in a wide variety of applications since their discovery over 20 years ago. Their myriad desirable material properties including exceptional mechanical strength, ...

Mitchell, Robert Revell, III

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Gas-supported high-photoactivity TiO2 nanotubes  

Science Conference Proceedings (OSTI)

By changing hydrothermal condition and post-heat-treatment temperature, silica-coated TiO2 nanotubes are obtained successfully. The effects of gas-supported process on tubular morphology, crystallinity, and photocatalytic activity are discussed. ...

Sheng Wang, Tao Wang, Yuanwei Ding, Youfeng Xu, Qiying Su, Yanlong Gao, Guohua Jiang, Wenxing Chen

2012-01-01T23:59:59.000Z

302

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H...  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Two of the major challenges for humanity in the next 20 years are the shrinking availability of fossil...

303

Diameter tuning of single-walled carbon nanotubes by diffusion plasma CVD  

Science Conference Proceedings (OSTI)

We have realized a diameter tuning of single-walled carbon nanotubes (SWNTs) by adjusting process gas pressures with plasma chemical vapor deposition (CVD). Detailed photoluminescence measurements reveal that the diameter distribution of SWNTs clearly ...

Toshiaki Kato; Shunsuke Kuroda; Rikizo Hatakeyama

2011-01-01T23:59:59.000Z

304

Ostwald ripening of platinum nanoparticles confined in a carbon nanotube/silica-templated cylindrical space  

Science Conference Proceedings (OSTI)

Sintering of nanoparticles mediated by an Ostwald ripening mechanism is generally assessed examining the final particle size distributions. Based on this methodology, a general approach for depositing platinum nanoparticles onto carbon nanotubes in solution ...

Cintia Mateo-Mateo, Carmen Vázquez-Vázquez, Moisés Pérez-Lorenzo, Verónica Salgueiriño, Miguel A. Correa-Duarte

2012-01-01T23:59:59.000Z

305

A Study on Carbon-Nanotube Local Oxidation Lithography Using an Atomic Force Microscope  

Science Conference Proceedings (OSTI)

In this paper, nanoscale anodic oxidation lithography using an atomic force microscope (AFM) is systematically studied on carbon nanotubes (CNTs). Trends between the produced feature size and the corresponding process parameters, such as applied voltage, ...

K. Kumar; O. Sul; S. Strauf; D. S. Choi; F. Fisher; M. G. Prasad; E. Yang

2011-07-01T23:59:59.000Z

306

Analysis on electro-thermal property of micro-bubble generator using carbon nanotube heating elements  

Science Conference Proceedings (OSTI)

Localized high temperature due to Joule heating in Carbon Nanotubes (CNTs) can generate micron-sized bubbles. Electro-thermal property of CNTs-based microbubble generator is characterized by finite element analysis in this paper. Water circumstance with ...

Wenli Zhou; Sanping Wan; Chao Zhu

2009-01-01T23:59:59.000Z

307

Transitional failure of carbon nanotube systems under a combination of tension and torsion  

Science Conference Proceedings (OSTI)

Transitional failure envelopes of single- and double-walled carbon nanotubes under combined tension-torsion are predicted using classical molecular dynamics simulations. The observations reveal that while the tensile failure load decreases with combined ...

Byeong-Woo Jeong

2012-01-01T23:59:59.000Z

308

Origami-inspired nanofabrication utilizing physical and magnetic properties of in situ grown carbon nanotubes  

E-Print Network (OSTI)

Carbon nanotubes (CNTs), in particular the vertically-aligned variety grown through a plasma enhanced chemical vapor deposition (PECVD)-based process, are highly versatile nanostructures that can be used in a variety of ...

In, Hyun Jin

2010-01-01T23:59:59.000Z

309

Photonic devices based on periodic arrays of carbon nanotubes and silicon nanopillars  

E-Print Network (OSTI)

reflection from Si surfaces. These arrays of Si inverted nanocones displayed a 3 to 4 fold enhanced reflection in the optical regime. These arrays find application in photovoltaic devices for enhancing the reflection of infrared (IR) radiations, which... -optical devices [9], solar cells to increase efficiency [10], optical antenna arrays [11, 12] and photonic crystals Chapter 2: Carbon nanotubes and nanophotonics devices 4 [13]. Carbon nanotubes are one of the most promising materials for device fabrication...

Butt, Haider

2012-02-07T23:59:59.000Z

310

System and method for controlling hydrogen elimination during carbon nanotube synthesis from hydrocarbons  

DOE Patents (OSTI)

A system and method for producing carbon nanotubes by chemical vapor deposition includes a catalyst support having first and second surfaces. The catalyst support is capable of hydrogen transport from the first to the second surface. A catalyst is provided on the first surface of the catalyst support. The catalyst is selected to catalyze the chemical vapor deposition formation of carbon nanotubes. A fuel source is provided for supplying fuel to the catalyst.

Reilly, Peter T. A. (Knoxville, TN)

2010-03-23T23:59:59.000Z

311

Multi-scale electrical and thermal properties of aligned multi-walled carbon nanotubes and their composites  

E-Print Network (OSTI)

Carbon nanotubes (CNTs) are a potential new component to be incorporated into existing aerospace structural composites for multi-functional (mechanical, electrical, thermal, etc.) property enhancement and tailoring. ...

Yamamoto, Namiko

2011-01-01T23:59:59.000Z

312

Carbon Nanotubes as Binder in Electrochemical Supercapacitor Malinda Caudle, Iowa State University Georgia Tech SURF 2011 Fellow  

E-Print Network (OSTI)

Carbon Nanotubes as Binder in Electrochemical Supercapacitor Malinda Caudle, Iowa State University. Introduction The development of supercapacitors would allow the electronics market to produce portable power

Li, Mo

313

Aligned carbon nanotube with electro-catalytic activity for oxygen reduction reaction  

DOE Patents (OSTI)

A catalyst for an electro-chemical oxygen reduction reaction (ORR) of a bundle of longitudinally aligned carbon nanotubes having a catalytically active transition metal incorporated longitudinally in said nanotubes. A method of making an electro-chemical catalyst for an oxygen reduction reaction (ORR) having a bundle of longitudinally aligned carbon nanotubes with a catalytically active transition metal incorporated throughout the nanotubes, where a substrate is in a first reaction zone, and a combination selected from one or more of a hydrocarbon and an organometallic compound containing an catalytically active transition metal and a nitrogen containing compound and an inert gas and a reducing gas is introduced into the first reaction zone which is maintained at a first reaction temperature for a time sufficient to vaporize material therein. The vaporized material is then introduced to a second reaction zone maintained at a second reaction temperature for a time sufficient to grow longitudinally aligned carbon nanotubes over the substrate with a catalytically active transition metal incorporated throughout the nanotubes.

Liu, Di-Jia (Naperville, IL); Yang, Junbing (Westmont, IL); Wang, Xiaoping (Naperville, IL)

2010-08-03T23:59:59.000Z

314

Enhancement of electron lifetime in dye-sensitized solar cells using anodically grown TiO2 nanotube/nanoparticle composite photoanodes  

Science Conference Proceedings (OSTI)

Dye-sensitized solar cells (DSCs) based on TiO"2 nanotube/nanoparticle (NT/NP) composite photoanodes were fabricated including different NT content into the NP network. The NPs expose large surface area for the dye anchoring, while the incorporated nanotubes ... Keywords: Anodic oxidation, Charge transport, Dye-sensitized solar cell, Electron lifetime, TiO2 nanotubes

Andrea Lamberti, Adriano Sacco, Stefano Bianco, Marzia Quaglio, Diego Manfredi, Candido Fabrizio Pirri

2013-11-01T23:59:59.000Z

315

Impact of three different TiO2 morphologies on hydrogen evolution by methonal assisted water-splitting: nanoparticles, nanotubes and  

E-Print Network (OSTI)

-splitting: nanoparticles, nanotubes and aerogels. (published in International Journal of Hydrogen Energy 36, 22 (2011, nanotubes and aerogels. These materials have shown different behaviours depending on both their composition of the samples (nanotubes or aerogels). Among all the tested samples, the TiO2 aerogel supported Pt one exhibited

316

Segregated Network Polymer-Carbon Nanotubes Composites For Thermoelectrics  

E-Print Network (OSTI)

Polymers are intrinsically poor thermal conductors, which are ideal for thermoelectrics, but low electrical conductivity and thermopower have excluded them as feasible candidates as thermoelectric materials in the past. However, recent progress in polymer technology, particularly nanomaterial-polymer composites, can bring them into degenerate semiconductor or metallic regimes by incorporating a small amount of conductive filler. I demonstrate that such polymer nanocomposites can be viable for light-weight and economical thermoelectrics by using a segregated network approach for the nanocomposite synthesis. The thermoelectric properties were further improved by a change of stabilizer and drying conditions. The thermoelectric properties of the segregated network nanocomposites were measured for carbon nanotubes and the thermoelectric figure of merit, ZT, was calculated at room temperature. The influence on thermoelectric properties from filler concentration, stabilizer materials and drying condition are also discussed.

Kim, Dasaroyong

2009-08-01T23:59:59.000Z

317

Nematic droplets in aqueous dispersions of carbon nanotubes  

E-Print Network (OSTI)

Aqueous dispersions of exfoliated, bile-salt stabilized single-wall carbon nanotubes exhibit a first order transition to a nematic liquid-crystalline phase. The nematic phase presents itself in the form of micron-sized nematic droplets also known as tactoids, freely floating in the isotropic host dispersion. The nematic droplets are spindle shaped and have an aspect ratio of about four, irrespective of their size. We attribute this to a director field that is uniform rather than bipolar, which is confirmed by polarization microscopy. It follows that the ratio of the anchoring strength and the surface tension must be about four, which is quite larger than predicted theoretically but in line with earlier observations of bipolar tactoids. From the scatter in the data we deduce that the surface tension of the coexisting isotropic and nematic phases must be extremely low, that is, of the order of nN/m.

Nicolas Puech; Eric Grelet; Philippe Poulin; Christophe Blanc; Paul van der Schoot

2013-06-23T23:59:59.000Z

318

Single-Wall Carbon Nanotubes as Transparent Electrodes for Photovoltaics  

Science Conference Proceedings (OSTI)

Transparent and electrically conductive coatings and films have a variety of uses in the fast-growing field of optoelectronic applications. Transparent electrodes typically include semiconductive metal oxides such as indium tin oxide (ITO), and conducting polymers such as poly(3,4-ethylenedioxythiophene), doped and stabilized with poly(styrenesulfonate) (PEDOT/PSS). In recent years, Eikos, Inc. has conceived and developed technologies to deliver novel alternatives using single-wall carbon nanotubes (SWNT). These technologies offer products having a broad range of conductivity, excellent transparency, neutral color tone, good adhesion, abrasion resistance as well as mechanical robustness. Additional benefits include ease of ambient processing and patterning capability. This paper reports our recent findings on achieving 2.6% and 1.4% efficiencies on nonoptimized organic photovoltaic cells employing SWNT as a transparent electrode.

Weeks, C.; Peltola, J.; Levitsky, I.; Glatkowski, P.; van de Lagemaat, J.; Rumbles, G.; Barnes, T.; Coutts, T.

2006-01-01T23:59:59.000Z

319

Laser ablation for the synthesis of carbon nanotubes  

SciTech Connect

Single walled carbon nanotubes are produced in a novel apparatus by the laser-induced ablation of moving carbon target. The laser used is of high average power and ultra-fast pulsing. According to various preferred embodiments, the laser produces and output above about 50 watts/cm.sup.2 at a repetition rate above about 15 MHz and exhibits a pulse duration below about 10 picoseconds. The carbon, carbon/catalyst target and the laser beam are moved relative to one another and a focused flow of "side pumped", preheated inert gas is introduced near the point of ablation to minimize or eliminate interference by the ablated plume by removal of the plume and introduction of new target area for incidence with the laser beam. When the target is moved relative to the laser beam, rotational or translational movement may be imparted thereto, but rotation of the target is preferred.

Holloway, Brian C; Eklund, Peter C; Smith, Michael W; Jordan, Kevin C; Shinn, Michelle

2012-11-27T23:59:59.000Z

320

Rheological and Electrical Transitions in Carbon Nanotube/Epoxy Suspensions  

E-Print Network (OSTI)

The rheological and electrical properties of suspensions of carbon nanotubes in an uncured epoxy resin were investigated by means of shear rheology and impedance spectroscopy. It was found that above an onset CNT weight fraction (0.1 wt %), the steady viscosity increased with CNT loading and presented a shear thinning behaviour. The concentration dependence of viscosity changed from a power law to an exponential with increasing shear rate, indicating a loss of interaction between aggregates and CNT network breakage. The fluid-to-solidlike and insulator-to-conductor transitions occurred in the same CNT weight fraction range between 0.5 and 0.6 wt %. The correspondence of these transitions was explained by the reduction of contact resistance between CNT by stiffening of the CNT network leading to improved electronic transport.

Aissa Allaoui; Nour-Eddine El Bounia

2013-10-04T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Generation of electromagnetic radiation based on nanotubes under a constant electric field and an electromagnetic wave field  

Science Conference Proceedings (OSTI)

The possible generation of radiation in the millimeter range based on nanotubes by an alternating (rapidly oscillating) electric field under a constant (or nonstationary) electric field is studied. Radiation enhancement is based on a periodic dependence of the current in nanotubes in such electric fields. The results of a mathematical simulation are presented.

Sadykov, N. R., E-mail: sadykov@rambler.ru; Scorkin, N. A. [South Ural State University (Russian Federation)

2012-02-15T23:59:59.000Z

322

The Effect of Single Walled Carbon Nanotubes on Lithium-Ion Batteries and Electric Double Layer Capacitors  

E-Print Network (OSTI)

The Effect of Single Walled Carbon Nanotubes on Lithium-Ion Batteries and Electric Double Layer power. #12;The Effect of Single Walled Carbon Nanotubes on Lithium- Ion Batteries and Electric Double of the Lithium-ion Battery (LIB). A LIB using only graphite in the anode was the control. SWNTs were mixed

Mellor-Crummey, John

323

Validity of approximations applied in calculations of single-wall metallic carbon nanotube current-voltage characteristics  

Science Conference Proceedings (OSTI)

The calculation results of dependencies of electric current in the infinitely long single-wall metallic carbon nanotubes of armchair type with different diameter values on the strength of constant and uniform longitudinal electric field applied to them ... Keywords: Boltzmann equation, Current---voltage characteristic, Electron---phonon transport, Single-wall carbon nanotube

Dmitry Pozdnyakov

2012-12-01T23:59:59.000Z

324

Experimental Observations of Multiple Solitons Generation in a Carbon-Nanotube Based Passively Mode-locked Fiber Laser  

Science Conference Proceedings (OSTI)

We report the experimental observations of multiple solitons gernration from a carbon nanotube (CNT) -based passively mode-locked fiber lasers. After a fiber-connector-type saturable absorber in which CNT is coated on the fiber connector end is successfully ... Keywords: fiber laser, multi-soliton generation, carbon nanotube

Kai Jiang; Songnian Fu; P. Shum

2010-04-01T23:59:59.000Z

325

Modeling of the performance of carbon nanotube bundle, cu/low-k and optical on-chip global interconnects  

Science Conference Proceedings (OSTI)

In this work, we have quantified and compared the performance of carbon nanotube (CNT) and optical interconnects with the existing technology of Cu/low-K interconnects for future high-performance ICs. We present these comparisons not only in terms of ... Keywords: Cu, Global interconnects, bandwidth density, carbon nanotube, latency, optics, power

Hoyeol Cho; Kyung-Hoae Koo; Pawan Kapur; Krishna C. Saraswat

2007-03-01T23:59:59.000Z

326

A rational self-sacrificing template route to LiMn2O4nanotubes and nanowires  

Science Conference Proceedings (OSTI)

Single-crystalline LiMn2O4 nanotubes and nanowires have been synthesized via a low-temperature molten salt synthesis method, using the prepared ?-MnO2 nanotubes and ?-MnO2 nanowires as the precursors ...

Baojun Yang; Xinsong Yuan; Duoli Chai

2011-01-01T23:59:59.000Z

327

Characterization of diffusion flames for synthesis of single-walled carbon nanotubes  

Science Conference Proceedings (OSTI)

Recent studies have shown that Fe/Si/O catalysts on the fuel side of an oxygen-enriched inverse diffusion flame produce micron-length single-walled carbon nanotubes at rapid rates (>100{mu}m/s). Despite the favorable catalyst/flame interaction for nanotube nucleation and growth, the catalyst lifetimes are only a few milliseconds. To increase catalyst lifetime and hence, carbon nanotube length, it is necessary to know how the local environment changes as the catalyst moves through the flame. A 2-D computational fluid dynamics model with detailed chemistry is employed to investigate the nature of the flame environment along various catalyst trajectories. The results indicate that temperature and species concentrations do not change significantly along individual catalyst trajectories, although not all trajectories experience the same environment due to the steep gradients in the radial direction. On the other hand, analysis of catalyst particle composition before and after nanotube growth shows that catalyst oxygen content decreases significantly during nanotube growth. This change in catalyst composition could affect the relative rates of carbon supply versus removal from the catalyst surface, such that carbon encapsulation and thus poisoning of the catalyst is favored after sufficient time. The results of this work indicate that catalyst deactivation, not a changing catalyst environment, is responsible for rapid encapsulation of the catalyst by amorphous carbon and thus, the short catalyst lifetimes observed in oxygen-enriched diffusion flames. (author)

Unrau, C.J.; Axelbaum, R.L. [Department of Energy, Environmental, Chemical Engineering/Center for Materials Innovation, Washington University, St. Louis, MO (United States); Katta, V.R. [Innovative Scientific Solutions, Inc., Dayton, OH (United States)

2010-09-15T23:59:59.000Z

328

Carbon nanotube substrates and catalyzed hot stamp for polishing and patterning the substrates  

DOE Patents (OSTI)

The present invention is generally directed to catalyzed hot stamp methods for polishing and/or patterning carbon nanotube-containing substrates. In some embodiments, the substrate, as a carbon nanotube fiber end, is brought into contact with a hot stamp (typically at 200-800.degree. C.), and is kept in contact with the hot stamp until the morphology/patterns on the hot stamp have been transferred to the substrate. In some embodiments, the hot stamp is made of material comprising one or more transition metals (Fe, Ni, Co, Pt, Ag, Au, etc.), which can catalyze the etching reaction of carbon with H.sub.2, CO.sub.2, H.sub.2O, and/or O.sub.2. Such methods can (1) polish the carbon nanotube-containing substrate with a microscopically smooth finish, and/or (2) transfer pre-defined patterns from the hot stamp to the substrate. Such polished or patterned carbon nanotube substrates can find application as carbon nanotube electrodes, field emitters, and field emitter arrays for displays and electron sources.

Wang, Yuhuang (Evanston, IL); Hauge, Robert H. (Houston, TX); Schmidt, Howard K. (Houston, TX); Kim, Myung Jong (Houston, TX); Kittrell, W. Carter (Houston, TX)

2009-09-08T23:59:59.000Z

329

Argonne CNM Highlight: New Gas Sensor Based on Multiwalled Carbon Nanotubes  

NLE Websites -- All DOE Office Websites (Extended Search)

New Gas Sensor Based on Multiwalled Carbon Nanotubes A new gas sensor based on multiwalled carbon nanotubes Hybrid sensor fabrication process: (top) SEM image of a few MWCNTs spanning across two neighboring Au fingers of the interdigitated electrode; (bottom) HRTEM image of a MWCNT uniformly coated with SnO nanocrystals. Argonne Center for Nanoscale Materials staff in the Nanofabrication & Devices Group together with collaborative users from the University of Wisconsin-Milwaukee have fabricated a miniaturized gas sensor using hybrid nanostructures consisting of SnO2 nanocrystals supported on multiwalled carbon nanotubes (MWCNTs). In contrast to the high-temperature operation required for SnO2 nanocrystals alone, and to the insensitivity towards H2

330

A Catalyst Wire-feed Arc Discharge for Synthesis of Carbon Nanotubes and  

NLE Websites -- All DOE Office Websites (Extended Search)

A Catalyst Wire-feed Arc Discharge for Synthesis of Carbon Nanotubes and A Catalyst Wire-feed Arc Discharge for Synthesis of Carbon Nanotubes and Graphene Particles This invention pertains to a highly effective arc-based synthesis of single wall carbon nanotubes and graphene particles using catalysts in the form of wires made from ion group alloys instead of commonly used catalyst powders. The catalyst wire can be introduced into the discharge either from the anode or cathode regions or into the inter-electrode gap. The catalyst introduction can be done automatically and controlled using feedback based on the ablation of the graphite electrode. To maintain simplicity and attractiveness for industrial applications, it is desirable that the catalyst composition be contained in a single wire alloy. No.: M-808 Inventor(s): Yevgeny Raitses

331

A Ni-Fe Layered Double Hydroxide-Carbon Nanotube Complex for Water Oxidation  

E-Print Network (OSTI)

Highly active, durable and cost-effective electrocatalysts for water oxidation to evolve oxygen gas hold a key to a range of renewable energy solutions including water splitting and rechargeable metal-air batteries. Here, we report the synthesis of ultrathin nickel iron layered double hydroxide nanoplates on mildly oxidized multi-walled carbon nanotubes. Incorporation of Fe into the nickel hydroxide induced the formation of NiFe-layered double hydroxide. The nanoplates were covalently attached to a network of nanotubes, affording excellent electrical wiring to the nanoplates. The ultra-thin Ni-Fe layered double hydroxide nanoplates/carbon nanotube complex was found to exhibit unusually high electro-catalytic activity and stability for oxygen evolution and outperformed commercial precious metal Ir catalysts.

Gong, Ming; Wang, Hailiang; Liang, Yongye; Wu, Justin Zachary; Zhou, Jigang; Wang, Jian; Regier, Tom; Wei, Fei; Dai, Hongjie

2013-01-01T23:59:59.000Z

332

Hydrogen-bond acidic functionalized carbon nanotubes (CNTs) with covalently-bound hexafluoroisopropanol groups  

DOE Green Energy (OSTI)

Fluorinated hydrogen-bond acidic groups are directly attached to the backbone of single walled carbon nanotubes (SWCNTs) without the introduction of intermediate electron donating surface groups. Hexafluoroalcohol functional groups are exceptionally strong hydrogen bond acids, and are added to the nanotube surface using the aryl diazonium approach to create hydrogen-bond acidic carbon nanotube (CNT) surfaces. These groups can promote strong hydrogen-bonding interactions with matrix materials in composites or with molecular species to be concentrated and sensed. In the latter case, this newly developed material is expected to find useful application in chemical sensors and in CNT-based preconcentrator devices for the detection of pesticides, chemical warfare agents and explosives.

Fifield, Leonard S.; Grate, Jay W.

2010-06-01T23:59:59.000Z

333

Continuous growth of single-wall carbon nanotubes using chemical vapor deposition  

DOE Patents (OSTI)

The invention relates to a chemical vapor deposition process for the continuous growth of a carbon single-wall nanotube where a carbon-containing gas composition is contacted with a porous membrane and decomposed in the presence of a catalyst to grow single-wall carbon nanotube material. A pressure differential exists across the porous membrane such that the pressure on one side of the membrane is less than that on the other side of the membrane. The single-wall carbon nanotube growth may occur predominately on the low-pressure side of the membrane or, in a different embodiment of the invention, may occur predominately in between the catalyst and the membrane. The invention also relates to an apparatus used with the carbon vapor deposition process.

Grigorian, Leonid (Raymond, OH); Hornyak, Louis (Evergreen, CO); Dillon, Anne C (Boulder, CO); Heben, Michael J (Denver, CO)

2008-10-07T23:59:59.000Z

334

Surface studies of hydroxylated multi-wall carbon nanotubes  

Science Conference Proceedings (OSTI)

CVD grown MWCNTs, of typical diameter 5 to 50 nm and with approximately 15-20 concentric graphene layers in the multi-walls, have been surface functionalised using the Fenton hydroxylation reaction. HRTEM reveals little physical difference between the treated and untreated materials; images from both exhibit similar multi-wall structure and contain evidence for some low-level disruption of the very outermost layers. Raman spectra from the two types of nanotubes are almost identical displaying the disorder (D) peaks at approximately 1350 cm{sup -1} and graphite (G) peaks at approximately 1580 cm{sup -1}, characteristic of graphene-based carbon materials, in approximately equal intensity ratios. Equilibrium adsorption data for nitrogen at 77 K leads to BET surface areas of 60.4 m{sup 2} g{sup -1} for the untreated and 71.8 m{sup 2} g{sup -1} for the hydroxylated samples; the increase in area being due to separation of the tube-bundles during functionalization. This is accompanied by a decrease in measured porosity, mostly at high relative pressures of nitrogen, i.e. where larger (meso 2-5 nm and macro >5 nm) pores are being filled, which is consistent with an attendant loss of inter-tube capillarity. X-ray photoelectron spectroscopy (XPS) shows that hydroxylation increases the nanotube surface oxygen level from 4.3 at.% to 22.3 at.%; chemical shift data indicate that approximately 75% of that oxygen is present as hydroxyl (-OH) groups. Water vapour adsorption by the hydroxylated surfaces leads to Type II isotherms which are characteristic of relatively high numbers of hydrogen bonding interactions compared to the untreated materials which exhibit Type III curves. This difference in polar surface energy is confirmed by calorimetric enthalpies of immersion in water which are -54 mJ m{sup -2} for the untreated and -192 mJ m{sup -2} for the hydroxylated materials. The treated materials therefore have significantly increased water wettability/dispersivity and a greater potential for cross-linking with matrix compounds. The mechanism by which hydroxylation occurs i.e. free radical (OH{sm_bullet}) attack and subsequent electrophilic addition at CC bonds in the graphene basal planes, is discussed.

Bradley, Robert [Department of Materials, University of Oxford, Parks Rd, Oxford, OX1 3PH, UK; Cassity, Kelby [Oak Ridge National Laboratory (ORNL); Andrews, Rodney [University of Kentucky, Lexington; Meier, Mark [University of Kentucky, Lexington; Osbeck, Susan [The Robert Gordon University, Aberdeen AB10 1FR, U.K.; Andreu, Aurik [The Robert Gordon University, Aberdeen AB10 1FR, U.K.; Johnston, Colin [Department of Materials, University of Oxford, Parks Rd, Oxford, OX1 3PH, UK; Crossley, Alison [Department of Materials, University of Oxford, Parks Rd, Oxford, OX1 3PH, UK

2012-01-01T23:59:59.000Z

335

Localized and directed lateral growth of carbon nanotubes from a porous template  

Science Conference Proceedings (OSTI)

We report on the growth of laterally oriented carbon nanotubes with both positional and directional control. The growth was done by chemical vapor deposition from Fe/Mo catalyst embedded inside a porous silicon medium which was formed electrochemically on the vertical faces of etched posts on a silicon substrate. A solution containing the catalyst was allowed to diffuse into the porous medium only in lithographically defined areas. Nanotubes grew only in the patterned areas with a preferred orientation normal to the edges of the etched posts.

S. J. Wind; R. Martel; Ph. Avouris

2002-01-01T23:59:59.000Z

336

Carbon nanotubes in almost homogeneous transverse magnetic field: exactly solvable model  

E-Print Network (OSTI)

Single-wall carbon nanotubes are considered in the presence of an external magnetic field with inhomogeneous transverse component. The continuum model is employed where the dynamics of the charge carriers is governed by the Dirac-Weyl equation. It is shown that a small fluctuation of the transverse field around a constant value represented by a finite-gap vector potential provides exact solutions of the stationary equation. An example is elaborated in detail. The spectrum of the system manifests remarkable stability with respect to small perturbations of the longitudinal momentum. Nonlinear, N=2 supersymmetry associated with the metallic and the maximally semi-conducting nanotubes is discussed.

Vit Jakubsky; Sengul Kuru; Javier Negro

2013-06-10T23:59:59.000Z

337

High-Tc superconductivity in entirely end-bonded multi-walled carbon nanotubes  

E-Print Network (OSTI)

We report that entirely end-bonded multi-walled carbon nanotubes (MWNTs) can show superconductivity with the transition temperature Tc as high as 12K that is approximately 40-times larger than those reported in ropes of single-walled nanotubes. We find that emergence of this superconductivity is very sensitive to junction structures of Au electrode/MWNTs. This reveals that only MWNTs with optimal numbers of electrically activated shells, which are realized by the end-bonding, can allow the superconductivity due to inter shell effects.

I. Takesue; J. Haruyama; N. Kobayashi; S. Chiashi; S. Maruyama; T. Sugai; H. Shinohara

2005-09-18T23:59:59.000Z

338

Analytic and computational micromechanics of clustering and interphase effects in carbon nanotube composites.  

Science Conference Proceedings (OSTI)

Effective elastic properties for carbon nanotube reinforced composites are obtained through a variety of micromechanics techniques. Using the in-plane elastic properties of graphene, the effective properties of carbon nanotubes are calculated utilizing a composite cylinders micromechanics technique as a first step in a two-step process. These effective properties are then used in the self-consistent and Mori-Tanaka methods to obtain effective elastic properties of composites consisting of aligned single or multi-walled carbon nanotubes embedded in a polymer matrix. Effective composite properties from these averaging methods are compared to a direct composite cylinders approach extended from the work of Hashin and Rosen (1964) and Christensen and Lo (1979). Comparisons with finite element simulations are also performed. The effects of an interphase layer between the nanotubes and the polymer matrix as result of functionalization is also investigated using a multi-layer composite cylinders approach. Finally, the modeling of the clustering of nanotubes into bundles due to interatomic forces is accomplished herein using a tessellation method in conjunction with a multi-phase Mori-Tanaka technique. In addition to aligned nanotube composites, modeling of the effective elastic properties of randomly dispersed nanotubes into a matrix is performed using the Mori-Tanaka method, and comparisons with experimental data are made. Computational micromechanical analysis of high-stiffness hollow fiber nanocomposites is performed using the finite element method. The high-stiffness hollow fibers are modeled either directly as isotropic hollow tubes or equivalent transversely isotropic effective solid cylinders with properties computed using a micromechanics based composite cylinders method. Using a representative volume element for clustered high-stiffness hollow fibers embedded in a compliant matrix with the appropriate periodic boundary conditions, the effective elastic properties are obtained from the finite element results. These effective elastic properties are compared to approximate analytical results found using micromechanics methods. The effects of an interphase layer between the high-stiffness hollow fibers and matrix to simulate imperfect load transfer and/or functionalization of the hollow fibers is also investigated and compared to a multi-layer composite cylinders approach. Finally the combined effects of clustering with fiber-matrix interphase regions are studied. The parametric studies performed herein were motivated by and used properties for single-walled carbon nanotubes embedded in an epoxy matrix, and as such are intended to serve as a guide for continuum level representations of such nanocomposites in a multi-scale modeling approach.

Seidel, Gary D.; Hammerand, Daniel Carl; Lagoudas, Dimitris C. (Texas A& M University, College Station, TX)

2006-01-01T23:59:59.000Z

339

Final report : LDRD project 79824 carbon nanotube sorting via DNA-directed self-assembly.  

SciTech Connect

Single-wall carbon nanotubes (SWNTs) have shown great promise in novel applications in molecular electronics, biohazard detection, and composite materials. Commercially synthesized nanotubes exhibit a wide dispersion of geometries and conductivities, and tend to aggregate. Hence the key to using these materials is the ability to solubilize and sort carbon nanotubes according to their geometric/electronic properties. One of the most effective dispersants is single-stranded DNA (ssDNA), but there are many outstanding questions regarding the interaction between nucleic acids and SWNTs. In this work we focus on the interactions of SWNTs with single monomers of nucleic acids, as a first step to answering these outstanding questions. We use atomistic molecular dynamics simulations to calculate the binding energy of six different nucleotide monophosphates (NMPs) to a (6,0) single-wall carbon nanotube in aqueous solution. We find that the binding energies are generally favorable, of the order of a few kcal/mol. The binding energies of the different NMPs were very similar in salt solution, whereas we found a range of binding energies for NMPs in pure water. The binding energies are sensitive to the details of the association of the sodium ions with the phosphate groups and also to the average conformations of the nucleotides. We use electronic structure (Density Functional Theory (DFT) and Moller-Plesset second order perturbation to uncorrelated Hartree Fock theory (MP2)) methods to complement the classical force field study. With judicious choices of DFT exchange correlation functionals, we find that DFT, MP2, and classical force field predictions are in qualitative and even quantitative agreement; all three methods should give reliable and valid predictions. However, in one important case, the interactions between ions and metallic carbon nanotubes--the SWNT polarization-induced affinity for ions, neglected in most classical force field studies, is found to be extremely large (on the order of electron volts) and may have important consequences for various SWNT applications. Finally, the adsorption of NMPs onto single-walled carbon nanotubes were studied experimentally. The nanotubes were sonicated in the presence of the nucleotides at various weight fractions and centrifuged before examining the ultraviolet absorbance of the resulting supernatant. A distinct Langmuir adsorption isotherm was obtained for each nucleotide. All of the nucleotides differ in their saturation value as well as their initial slope, which we attribute to differences both in nucleotide structure and in the binding ability of different types or clusters of tubes. Results from this simple system provide insights toward development of dispersion and separation methods for nanotubes: strongly binding nucleotides are likely to help disperse, whereas weaker ones may provide selectivity that may be beneficial to a separation process.

Robinson, David B; Leung, Kevin; Rempe, Susan B.; Dossa, Paul D.; Frischknecht, Amalie Lucile; Martin, Marcus Gary

2007-10-01T23:59:59.000Z

340

A nanotube based electron microbeam cellular irradiator for radiobiology research  

Science Conference Proceedings (OSTI)

A prototype cellular irradiator utilizing a carbon nanotube (CNT) based field emission electron source has been developed for microscopic image-guided cellular region irradiation. The CNT cellular irradiation system has shown great potential to be a high temporal and spatial resolution research tool to enable researchers to gain a better understanding of the intricate cellular and intercellular microprocesses occurring following radiation deposition, which is essential to improving radiotherapy cancer treatment outcomes. In this paper, initial results of the system development are reported. The relationship between field emission current, the dose rate, and the dose distribution has been investigated. A beam size of 23 {mu}m has been achieved with variable dose rates of 1-100 Gy/s, and the system dosimetry has been measured using a radiochromic film. Cell irradiation has been demonstrated by the visualization of H2AX phosphorylation at DNA double-strand break sites following irradiation in a rat fibroblast cell monolayer. The prototype single beam cellular irradiator is a preliminary step to a multipixel cell irradiator that is under development.

Bordelon, David E. [Curriculum in Applied and Materials Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Zhang Jian; Graboski, Sarah; Cox, Adrienne; Schreiber, Eric; Chang, Sha [Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Zhou, Otto Z. [Department of Physics and Astronomy, Curriculum in Applied and Materials Sciences, and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599 (United States)

2008-12-15T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Radial elasticity of multi-walled boron nitride nanotubes  

Science Conference Proceedings (OSTI)

We investigated the radial mechanical properties of multi-walled boron nitride nanotubes (MW-BNNTs) using atomic force microscopy. The employed MW-BNNTs were synthesized using pressurized vapor/condenser (PVC) methods and were dispersed in aqueous solution using ultrasonication methods with the aid of ionic surfactants. Our nanomechanical measurements reveal the elastic deformational behaviors of individual BNNTs with two to four tube walls in their transverse directions. Their effective radial elastic moduli were obtained through interpreting their measured radial deformation profiles using Hertzian contact mechanics models. Our results capture the dependences of the effective radial moduli of MW-BNNTs on both the tube outer diameter and the number of tube layers. The effective radial moduli of double-walled BNNTs are found to be several-fold higher than those of single-walled BNNTs within the same diameter range. Our work contributes directly to a complete understanding of the fundamental structural and mechanical properties of BNNTs and the pursuits of their novel structural and electronics applications.

Michael W. Smith, Cheol Park, Meng Zheng, Changhong Ke ,In-Tae Bae, Kevin Jordan

2012-02-01T23:59:59.000Z

342

Microwave-assisted hydrothermal synthesis of porous SnO{sub 2} nanotubes and their lithium ion storage properties  

SciTech Connect

Porous SnO{sub 2} nanotubes have been synthesized by a rapid microwave-assisted hydrothermal process followed by annealing in air. The detailed morphological and structural studies indicate that the SnO{sub 2} tubes typically have diameters from 200 to 400 nm, lengths from 0.5 to 1.5 {mu}m and wall thicknesses from 50 to 100 nm. The SnO{sub 2} nanotubes are self-assembled by interconnected nanocrystals with sizes {approx}8 nm resulting in a specific surface area of {approx}54 m{sup 2} g{sup -1}. The pristine SnO{sub 2} nanotubes are used to fabricate lithium half cells to evaluate their lithium ion storage properties. The porous SnO{sub 2} nanotubes are characteristic with high lithium ion storage capacity, that is found to be 1258, 951, 757, 603, 458, and 288 mAh g{sup -1}, at 0.1, 0.2, 0.5, 1, 2, and 4C, respectively. The enhanced electrochemical properties of the SnO{sub 2} nanotubes can be ascribed to their unique geometry and porous structures. - Graphical abstract: Porous SnO{sub 2} nanotubes are synthesized by a fast microwave-assisted hydrothermal process and exhibit high lithium ion storage properties due to their unique geometry and porous characteristics. Highlights: Black-Right-Pointing-Pointer A microwave-assisted hydrothermal method was used to prepare porous SnO{sub 2} nanotubes. Black-Right-Pointing-Pointer The porous SnO{sub 2} nanotubes have abundant mesopores on their tube walls. Black-Right-Pointing-Pointer The porous SnO{sub 2} nanotubes possess high lithium ion storage properties. Black-Right-Pointing-Pointer Our results may promote the development of high-performance anode materials.

Wang, H.E., E-mail: hongen.wang@gmail.com [Department of Physics and Materials Science, City University of Hong Kong (Hong Kong); Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong (Hong Kong); Xi, L.J.; Ma, R.G. [Department of Physics and Materials Science, City University of Hong Kong (Hong Kong); Lu, Z.G. [School of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Chung, C.Y. [Department of Physics and Materials Science, City University of Hong Kong (Hong Kong); Bello, I. [Department of Physics and Materials Science, City University of Hong Kong (Hong Kong); Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong (Hong Kong); Zapien, J.A., E-mail: apjazs@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong (Hong Kong); Center of Super-Diamond and Advanced Films (COSDAF), City University of Hong Kong (Hong Kong)

2012-06-15T23:59:59.000Z

343

Very long single- and few-walled boron nitride nanotubes via the pressurized vapor/condenser method  

Science Conference Proceedings (OSTI)

Boron nitride nanotubes (BNNTs) are desired for their exceptional mechanical, electronic, thermal, structural, textural, optical, and quantum properties. A new method for producing long, small-diameter, single- and few-walled, boron nitride nanotubes (BNNTs) in macroscopic quantities is reported. The pressurized vapor/condenser (PVC) method produces, without catalysts, highly crystalline, very long, small-diameter, BNNTs. Palm-sized, cotton-like masses of BNNT raw material were grown by this technique and spun directly into centimeters-long yarn. Nanotube lengths were observed to be 100 times that of those grown by the most closely related method. Self-assembly and growth models for these long BNNTs are discussed.

Michael W. Smith, Kevin Jordan, Cheol Park, Jae-Woo Kim, Peter Lillehei, Roy Crooks, Joycelyn Harrison

2009-11-01T23:59:59.000Z

344

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Two of the major challenges for humanity in the next 20 years are the shrinking availability of fossil fuels and the global warming and potential climate changes that result from their ever-increasing use. One possible solution to these problems is to use an energy carrier such as hydrogen, and ways to produce and store hydrogen in electric power plants and vehicles is a major research focus for materials scientists and chemists. To realize hydrogen-powered transport, for example, it is necessary to find ways to store hydrogen onboard vehicles efficiently and safely. Nanotechnology in the form of single-walled carbon nanotubes provides a candidate storage medium. A U.S., German, and Swedish collaboration led by researchers from the Stanford Synchrotron Radiation Laboratory (SSRL) used ALS Beamline 11.0.2 and SSRL Beamline 5-1 to investigate the chemical interaction of hydrogen with single-walled carbon nanotubes (SWCNs). Their findings demonstrate substantial hydrogen storage is both feasible and reversible.

345

Oxygen Reduction Activity of PtxNi1-x Alloy Nanoparticles on Multiwall Carbon Nanotubes  

E-Print Network (OSTI)

PtxNi1 - x nanoparticles (Pt:Ni; 1:0, 4:1, 3:1 and 0.7:1) of ~5 nm, were synthesized on carboxylic acid-functionalized multiwall carbon nanotubes (PtxNi1 - x NPs/MWNT). The oxygen reduction reaction (ORR) activity measurements ...

Kim, Junhyung

346

Growth of carbon nanotubes on carbon/cobalt films with different sp2/sp3 ratios  

Science Conference Proceedings (OSTI)

The need of barrier layer such as SiO2 for carbon nanotubes (CNTs) growth limits their performance in electronic applications. In this study, conductive carbon/metal (carbon/cobalt--C:Co) composite films with the same metal content, but different ...

Naiyun Xu, Siu Hong Tsang, Beng Kang Tay, Edwin Hang Tong Teo, Chee Mang Ng

2013-01-01T23:59:59.000Z

347

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Two of the major challenges for humanity in the next 20 years are the shrinking availability of fossil fuels and the global warming and potential climate changes that result from their ever-increasing use. One possible solution to these problems is to use an energy carrier such as hydrogen, and ways to produce and store hydrogen in electric power plants and vehicles is a major research focus for materials scientists and chemists. To realize hydrogen-powered transport, for example, it is necessary to find ways to store hydrogen onboard vehicles efficiently and safely. Nanotechnology in the form of single-walled carbon nanotubes provides a candidate storage medium. A U.S., German, and Swedish collaboration led by researchers from the Stanford Synchrotron Radiation Laboratory (SSRL) used ALS Beamline 11.0.2 and SSRL Beamline 5-1 to investigate the chemical interaction of hydrogen with single-walled carbon nanotubes (SWCNs). Their findings demonstrate substantial hydrogen storage is both feasible and reversible.

348

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Storage in Carbon Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Wednesday, 28 June 2006 00:00 Two of the major challenges for humanity in the next 20 years are the shrinking availability of fossil fuels and the global warming and potential climate changes that result from their ever-increasing use. One possible solution to these problems is to use an energy carrier such as hydrogen, and ways to produce and store hydrogen in electric power plants and vehicles is a major research focus for materials scientists and chemists. To realize hydrogen-powered transport, for example, it is necessary to find ways to store hydrogen onboard vehicles efficiently and safely. Nanotechnology in the form of single-walled carbon nanotubes provides a candidate storage medium. A U.S., German, and Swedish collaboration led by researchers from the Stanford Synchrotron Radiation Laboratory (SSRL) used ALS Beamline 11.0.2 and SSRL Beamline 5-1 to investigate the chemical interaction of hydrogen with single-walled carbon nanotubes (SWCNs). Their findings demonstrate substantial hydrogen storage is both feasible and reversible.

349

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Two of the major challenges for humanity in the next 20 years are the shrinking availability of fossil fuels and the global warming and potential climate changes that result from their ever-increasing use. One possible solution to these problems is to use an energy carrier such as hydrogen, and ways to produce and store hydrogen in electric power plants and vehicles is a major research focus for materials scientists and chemists. To realize hydrogen-powered transport, for example, it is necessary to find ways to store hydrogen onboard vehicles efficiently and safely. Nanotechnology in the form of single-walled carbon nanotubes provides a candidate storage medium. A U.S., German, and Swedish collaboration led by researchers from the Stanford Synchrotron Radiation Laboratory (SSRL) used ALS Beamline 11.0.2 and SSRL Beamline 5-1 to investigate the chemical interaction of hydrogen with single-walled carbon nanotubes (SWCNs). Their findings demonstrate substantial hydrogen storage is both feasible and reversible.

350

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Two of the major challenges for humanity in the next 20 years are the shrinking availability of fossil fuels and the global warming and potential climate changes that result from their ever-increasing use. One possible solution to these problems is to use an energy carrier such as hydrogen, and ways to produce and store hydrogen in electric power plants and vehicles is a major research focus for materials scientists and chemists. To realize hydrogen-powered transport, for example, it is necessary to find ways to store hydrogen onboard vehicles efficiently and safely. Nanotechnology in the form of single-walled carbon nanotubes provides a candidate storage medium. A U.S., German, and Swedish collaboration led by researchers from the Stanford Synchrotron Radiation Laboratory (SSRL) used ALS Beamline 11.0.2 and SSRL Beamline 5-1 to investigate the chemical interaction of hydrogen with single-walled carbon nanotubes (SWCNs). Their findings demonstrate substantial hydrogen storage is both feasible and reversible.

351

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Hydrogen Storage in Carbon Nanotubes Through Formation of C-H Bonds Print Two of the major challenges for humanity in the next 20 years are the shrinking availability of fossil fuels and the global warming and potential climate changes that result from their ever-increasing use. One possible solution to these problems is to use an energy carrier such as hydrogen, and ways to produce and store hydrogen in electric power plants and vehicles is a major research focus for materials scientists and chemists. To realize hydrogen-powered transport, for example, it is necessary to find ways to store hydrogen onboard vehicles efficiently and safely. Nanotechnology in the form of single-walled carbon nanotubes provides a candidate storage medium. A U.S., German, and Swedish collaboration led by researchers from the Stanford Synchrotron Radiation Laboratory (SSRL) used ALS Beamline 11.0.2 and SSRL Beamline 5-1 to investigate the chemical interaction of hydrogen with single-walled carbon nanotubes (SWCNs). Their findings demonstrate substantial hydrogen storage is both feasible and reversible.

352

12 American Ceramic Society Bulletin, Vol. 85, No. 7 Nanotube `Sandwiches' Could  

E-Print Network (OSTI)

, they deposit a forest of carbon nanotubes across the surface of a cloth woven from fibers of silicon carbide sili- con carbide fibers. TEM image of the electrospun fibers fired at 1500°C/1h. (Bar = 100 nm Composites Reinforced composite fabrics made from woven ceramic fibers have been used for decades

Azad, Abdul-Majeed

353

Nano Letters 8, 4477-4482 (2008) NANO-CRYSTALLOGRAPHY OF INDIVIDUAL CARBON NANOTUBES  

E-Print Network (OSTI)

Nano Letters 8, 4477- 4482 (2008) 1 NANO-CRYSTALLOGRAPHY OF INDIVIDUAL CARBON NANOTUBES N. Bozovi 1 meV energy resolution and 1 nm spatial resolution.1 The later should enable nano-crystallography ­ XRD study of individual nano-particles. The commissioning of NSLS II will take some time -- the plan

Homes, Christopher C.

354

Diameter-controlled Growth of Single-walled Carbon Nanotubes by Using Nano-Diamonds  

E-Print Network (OSTI)

Diameter-controlled Growth of Single-walled Carbon Nanotubes by Using Nano-Diamonds Shohei Chiashi diameter attract attention. Here, we perform CVD growth by using nano-diamond particles as the catalyst [1] and investigate the CVD condition dependence of SWNT tube diameter. The average diameter of the as-received nano

Maruyama, Shigeo

355

Flexible and transparent supercapacitor based on In2O3 nanowire/carbon nanotube heterogeneous films  

E-Print Network (OSTI)

Flexible and transparent supercapacitor based on In2O3 nanowire/carbon nanotube heterogeneous films; accepted 17 December 2008; published online 28 January 2009 In this paper, a supercapacitor galvanostatic measurements. In addition, to study the stability of flexible and transparent supercapacitor

Zhou, Chongwu

356

Compact-designed supercapacitors using free-standing single-walled carbon nanotube films  

E-Print Network (OSTI)

Compact-designed supercapacitors using free-standing single-walled carbon nanotube films Zhiqiang0ee00261e We reported the realization of assembling compact-designed supercapacitors using large) were achieved from the prepared SWCNT film-based compact-designed supercapacitors with small equivalent

Wang, Wei Hua

357

Stretchable Supercapacitors Based on Buckled Single-Walled Carbon Nanotube Macrofilms  

E-Print Network (OSTI)

Stretchable Supercapacitors Based on Buckled Single-Walled Carbon Nanotube Macrofilms By Cunjiang to accommodate large strains while retaining intact function. Of various power-source devices, supercapacitors in supercapacitors is the development of new electrode materials. Recently, CNTs have been studied as good candidates

Jiang, Hanqing

358

Carbon Nanotube Based Supercapacitors Calvin Davis, Georgia Institute of Technology, SURF 2010 Fellow  

E-Print Network (OSTI)

Carbon Nanotube Based Supercapacitors Calvin Davis, Georgia Institute of Technology, SURF 2010 density, which is why much research has been put into super capacitors. Supercapacitors, or electric. Supercapacitors also make use of an electrolyte for the purpose of transporting ions between the two electrodes1

Li, Mo

359

Three dimensional solid-state supercapacitors from aligned single-walled carbon nanotube array templates  

E-Print Network (OSTI)

Three dimensional solid-state supercapacitors from aligned single-walled carbon nanotube array- thermore, modeling of supercapacitor architectures utilizing other dielectric layers suggests the ability, and supercapacitor technologies, are being adapted and optimized with nanostructured compo- nents [1­5]. The promise

Gordon, Roy

360

Polyaniline modified graphene and carbon nanotube composite electrode for asymmetric supercapacitors of high energy density  

E-Print Network (OSTI)

supercapacitors of high energy density Qian Cheng a,b , Jie Tang a,b,**, Norio Shinya b , Lu-Chang Qin c as supercapacitor electrodes. Energy density of 188 Wh kgÃ?1 has been obtained. Graphene composite with carbon April 2013 Keywords: Supercapacitor Graphene Carbon nanotube PANI a b s t r a c t Graphene and single

Qin, Lu-Chang

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Anomalous thermal conduction characteristics of phase change composites with single walled carbon nanotube inclusions  

E-Print Network (OSTI)

transport path in a non-linear way which is in consistent with the simulation results reported in Ref.23. Besides, recent simulation study suggest that alkane molecules surrounding the nanotubes when frozen. Wang, H. Q. Xie, and Z. Xin, Thermochim. Acta 488 (1-2), 39 (2009). 9 R. Zheng, J. Gao, J. Wang, and G

Maruyama, Shigeo

362

Composites of Single-Walled Carbon Nanotubes and Polystyrene: Preparation and Electrical Conductivity  

E-Print Network (OSTI)

of the nanotube material itself. From conductivity measurements of individual tubes and bundles, Skakalova36. Electrical conductivity of individual bundles of metallic carbon nano- tubes reaches the value of 104 S/cm,2 thresholds of con- ductivity, the plateau conductivities, and the lengths and diameters of tube bundles

Resasco, Daniel

363

Arrays of Sealed Silicon Nanotubes As Anodes for Lithium Ion Batteries  

E-Print Network (OSTI)

,12 nanowires13-17 (NW), bundled Si nanotubes,18 and thin films19 as candidate anode materials in lithium ion morphology change. In particular, the axial void spaces of the Si NTs provide additional free surfaces physics, to account for experimental observations and to derive optimized dimen- sions in the tubes

Rogers, John A.

364

Irradiation effects in carbon nanotubes A.V. Krasheninnikov *, K. Nordlund  

E-Print Network (OSTI)

of the tube (a). A bundle of nanotubes (view along the tube axes) after the impact of a 500-eV Ar ion (b as well [20]. The bundles were irradiated with an 500-eV Arþ ion beam followed by transport measurements as masks against irradiation (to protect the areas below the tubes from sputtering) may be * Corresponding

Krasheninnikov, Arkady V.

365

Enhanced thermal conductivity of ethylene glycol with single-walled carbon nanotube inclusions  

E-Print Network (OSTI)

with the Hamilton-Crosser model, the Lu-Lin model, Nan`s effective medium theory and the Hashin-Strikman model to rest of the models. Networking of nanotubes to form a tri-dimensional structure was considered #12;models. Therefore, more studies need to be performed to measure the effective thermal conductivity

Maruyama, Shigeo

366

Temperature dependent thermal conductivity increase of aqueous nanofluid with single walled carbon nanotube inclusions  

E-Print Network (OSTI)

the thermal conductivity at higher temperatures up to 6%. Computational modeling of SWCNTs in water using of water seeded with single-walled carbon nanotubes (SWCNT) synthesized using the alcohol catalytic this fluid for practical applications. We compare experimental results with existing analytical models

Maruyama, Shigeo

367

NANO TOOLS & PRODUCTS IN MICRO & NANOTECHNOLOGY Engineered Carbon Nanotube (CNT) and  

E-Print Network (OSTI)

MICRO NANO TOOLS & PRODUCTS IN MICRO & NANOTECHNOLOGY Engineered Carbon Nanotube (CNT aligned nanorods, helices, and chevrons. Hybrid Nano-CMOS Chips--Hewlett-Packard Laboratories www coating. The result is a uni- form, durable nano-thin film treatment that delivers quantum physical

368

Nano Res (2010) 3: 170173170 Synthesis and Characterization of WS2 Inorganic Nanotubes with  

E-Print Network (OSTI)

Nano Res (2010) 3: 170­173170 Synthesis and Characterization of WS2 Inorganic Nanotubes]. Folding and bonding of edge atoms on the periphery of the quasi two-dimensional planar nano- structure this nanotubular structure is suitable for capillary filling using molten metal halides. Nano Res (2010) 3: 170

Davis, Ben G.

369

Graphene/Carbon Nanotube Films Prepared by Solution Casting for Electrochemical Energy Storage  

Science Conference Proceedings (OSTI)

Graphene oxide/carbon nanotube (GO/CNT) films with different CNT contents were prepared by a solution-casting method. The oxygen-containing groups on the GO/CNT films were removed by thermal annealing at 200 °C and the corresponding hybrid ...

Juan-Juan Li; Yan-Wen Ma; Xu Jiang; Xiao-Miao Feng; Qu-Li Fan; Wei Huang

2012-01-01T23:59:59.000Z

370

Synthesis of high-quality carbon nanotube arrays without the assistance of water  

Science Conference Proceedings (OSTI)

Long and high-quality carbon nanotube (CNT) arrays have been synthesized through a chemical vapor deposition process. The Fe/Al2O3 on silicon was used as the catalyst, ethylene as the carbon source, and a gasmixture of Ar and H2 ...

Yongfeng Luo, Xinjun Wang, Mengdong He, Xi Li, Hong Chen

2012-01-01T23:59:59.000Z

371

Electromagnetic wave interactions with 2D arrays of single-wall carbon nanotubes  

Science Conference Proceedings (OSTI)

We report, for the first time, the scattering, absorption, and reflection characteristics of 2D arrays of finite-length, armchair, single-walled carbon nanotubes (SWNTs) in the visible frequency regime. The analysis is based on the Finite-Element-Method ...

Taha A. Elwi; Hussain M. Al-Rizzo

2011-01-01T23:59:59.000Z

372

RF/microwave properties of nanotubes and nanowires : LDRD Project 105876 final report.  

Science Conference Proceedings (OSTI)

LDRD Project 105876 was a research project whose primary goal was to discover the currently unknown science underlying the basic linear and nonlinear electrodynamic response of nanotubes and nanowires in a manner that will support future efforts aimed at converting forefront nanoscience into innovative new high-frequency nanodevices. The project involved experimental and theoretical efforts to discover and understand high frequency (MHz through tens of GHz) electrodynamic response properties of nanomaterials, emphasizing nanowires of silicon, zinc oxide, and carbon nanotubes. While there is much research on DC electrical properties of nanowires, electrodynamic characteristics still represent a major new frontier in nanotechnology. We generated world-leading insight into how the low dimensionality of these nanomaterials yields sometimes desirable and sometimes problematic high-frequency properties that are outside standard model electron dynamics. In the cases of silicon nanowires and carbon nanotubes, evidence of strong disorder or glass-like charge dynamics was measured, indicating that these materials still suffer from serious inhomogeneities that limit there high frequency performance. Zinc oxide nanowires were found to obey conventional Drude dynamics. In all cases, a significant practical problem involving large impedance mismatch between the high intrinsic impedance of all nanowires and nanotubes and high-frequency test equipment had to be overcome.

Scrymgeour, David; Lee, Mark; Hsu, Julia W. P.; Highstrete, Clark

2009-09-01T23:59:59.000Z

373

On emission of Cerenkov X-rays by electrons in carbon nanotubes  

SciTech Connect

Conditions are considered for generating Cerenkov X-rays by an electron beam propagating inside a bundle of carbon nanotubes upon synchronisation of the electron movement with one of the slow spatial harmonics of the electromagnetic field of a crystal tube. (cerenkov radiation)

Rivlin, L A [Moscow State Institute of Radio Engineering, Electronics and Automatics (Technical University), Moscow (Russian Federation)

2007-09-30T23:59:59.000Z

374

Non-Fourier heat conduction in a single-walled carbon nanotube: Classical molecular dynamics simulations  

SciTech Connect

Nonstationary heat conduction in a single-walled carbon nanotube was investigated by applying a local heat pulse with duration of subpicoseconds. The investigation was based on classical molecular dynamics simulations, where the heat pulse was generated as coherent fluctuations by connecting a thermostat to the local cell for a short duration. The heat conduction through the nanotube was observed in terms of spatiotemporal temperature profiles. Results of the simulations exhibit non-Fourier heat conduction where a distinct amount of heat is transported in a wavelike form. The geometry of carbon nanotubes allows us to observe such a phenomenon in the actual scale of the material. The resulting spatiotemporal profile was compared with the available macroscopic equations, the so-called non-Fourier heat conduction equations, in order to investigate the applicability of the phenomenological models to a quasi-one-dimensional system. The conventional hyperbolic diffusion equation fails to predict the heat conduction due to the lack of local diffusion. It is shown that this can be remedied by adopting a model with dual relaxation time. Further modal analyses using wavelet transformations reveal a significant contribution of the optical phonon modes to the observed wavelike heat conduction. The result suggests that, in carbon nanotubes with finite length where the long-wavelength acoustic phonons behave ballistically, even optical phonons can play a major role in the non-Fourier heat conduction.

Shiomi, Junichiro; Maruyama, Shigeo [Department of Mechanical Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

2006-05-15T23:59:59.000Z

375

Zipper Mechanism of Nanotube Fusion: Theory and Experiment Mina Yoon,1  

E-Print Network (OSTI)

-assembly of nanoscale devices with complex geometries. As potential building blocks of nanotechnology Department of Materials Science & Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 to explain the unusually fast fusion process of carbon nanotubes. We identify the detailed pathway for two

Tománek, David

376

Tendencies in scientific output on carbon nanotubes and graphene in global centers of excellence for nanotechnology  

Science Conference Proceedings (OSTI)

A change has been taking place in the world of nanotechnologies since 2009, marking the beginning of a new era of end consumer goods related to these new technologies. In this article, our aim is to know the dominant tendencies observed in scientific ... Keywords: Carbon nanotubes (CNTs), Graphene, Nanotechnology applications, Scientific output

Goio Etxebarria; Mikel Gomez-Uranga; Jon Barrutia

2012-04-01T23:59:59.000Z

377

Carbon nanotube, graphene and atomic wires as next generation interconnects: current status and future promise  

Science Conference Proceedings (OSTI)

Carbon based metal wires such as carbon nanotube (CNT) and graphene nano ribbon (GNR) attracted much attention for possible applications as future interconnects. In particular, both CNTs and GNRs have long electron mean free path (~ µ), high carrier ... Keywords: design, performance, quantum simulation, reliability

Saroj K. Nayak

2009-07-01T23:59:59.000Z

378

Field-Flow Fractionation of Carbon Nanotubes and Related Materials  

Science Conference Proceedings (OSTI)

During the grant period, we carried out FFF studies of carbonaceous soot, single-walled and multi-walled carbon nanotubes, carbon nano-onions and polyoxometallates. FFF alone does not provide enough information to fully characterize samples, so our suite of characterization techniques grew to include light scattering (especially Photon Correlation Spectroscopy), scanning and transmission electron microscopy, thermogravimetric analysis and spectroscopic methods. We developed convenient techniques to deposit and examine minute FFF fractions by electron microscopy. In collaboration with Arthur Cammers (University of Kentucky), we used Flow Field-Flow Fractionation (Fl-FFF) to monitor the solution-phase growth of keplerates, a class of polyoxometallate (POM) nanoparticles. We monitored the evolution of Mo-POM nanostructures over the course of weeks by by using flow field-flow fractionation and corroborated the nanoparticle structures by using transmission electron microscopy (TEM). Total molybdenum in the solution and precipitate phases was monitored by using inductively coupled plasma analyses, and total Mo-POM concentration by following the UV-visible spectra of the solution phase. We observe crystallization-driven formation of (Mo132) keplerate and solution phase-driven evolution of structurally related nanoscopic species (3-60 nm). FFF analyses of other classes of materials were less successful. Attempts to analyze platelets of layered materials, including exfoliated graphite (graphene) and TaS2 and MoS2, were disappointing. We were not able to optimize flow conditions for the layered materials. The metal sulfides react with the aqueous carrier liquid and settle out of suspension quickly because of their high density.

John P. Selegue

2011-11-17T23:59:59.000Z

379

Methodology, morphology, and optimization of carbon nanotube growth for improved energy storage in a double layer capacitor  

E-Print Network (OSTI)

The goal of this thesis is to optimize the growth of carbon nanotubes (CNTs) on a conducting substrate for use as an electrode to improve energy density in a double-layer capacitor. The focus has been on several areas, ...

Ku, Daniel C. (Daniel Chung-Ming), 1985-

2009-01-01T23:59:59.000Z

380

Tensile mechanical properties and strengthening mechanism of hybrid carbon nanotube and silicon carbide nanoparticle-reinforced magnesium alloy composites  

Science Conference Proceedings (OSTI)

AZ91 magnesium alloy hybrid composites reinforced with different hybrid ratios of carbon nanotubes (CNTs) and silicon carbide (SiC) nanoparticulates were fabricated by semisolid stirring assisted ultrasonic cavitation. The results showed that grains ...

Xia Zhou; Depeng Su; Chengwei Wu; Liming Liu

2012-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Sources of variability and uncertainty in LCA of single wall carbon nanotubes for Li-ion batteries in electric vehicles  

Science Conference Proceedings (OSTI)

Production alternatives for single-walled carbon nanotubes (SWCNT) such as chemical vapor deposition, laser, arc and flame, vary widely in material and energy yields, catalyst requirements and product characteristics. The overall environmental profile ...

Thomas P. Seager; Ryne P. Raffaelle; Brian J. Landi

2008-05-01T23:59:59.000Z

382

Electrochemical degradation characteristics of refractory organic pollutants in coking wastewater on multiwall carbon nanotube-modified electrode  

Science Conference Proceedings (OSTI)

The multiwall carbon nanotube-mollified electrode (MWCNT-ME) was fabricated and its electrocatalytic activity of refractory organic pollutants of coking wastewater was investigated. The surface morphology, absorption properties, and the electrochemical ...

Yan Wang; Shujing Sun; Guifu Ding; Hong Wang

2012-01-01T23:59:59.000Z

383

Synthesis and Oxygen Reduction Reaction Activity of Atomic and Nanoparticle Gold on Thiol-Functionalized Multiwall Carbon Nanotubes  

E-Print Network (OSTI)

We demonstrated the self-assembly of atomic Au on thiol-functionalized multiwall carbon nanotubes through covalent bonding and the formation of Au nanoparticles (NPs) upon a subsequent thermal treatment. Au NPs of 3.4 nm ...

Kim, Junhyung

384

A review on nanomaterial dispersion, microstructure, and mechanical properties of carbon nanotube and nanofiber reinforced cementitious composites  

Science Conference Proceedings (OSTI)

Excellent mechanical, thermal, and electrical properties of carbon nanotubes (CNTs) and nanofibers (CNFs) have motivated the development of advanced nanocomposites with outstanding and multifunctional properties. After achieving a considerable success ...

Shama Parveen, Sohel Rana, Raul Fangueiro

2013-01-01T23:59:59.000Z

385

Tunable Raman spectroscopy study of CVD and peapod-derived bundled and individual double-wall carbon nanotubes  

E-Print Network (OSTI)

We use 40 laser excitation energies to analyze the differences in the Raman spectra from chemical vapor deposition-derived double-wall carbon nanotube (CVD-DWNT) bundles, fullerene-derived DWNT bundles (C[subscript 60]-DWNTs), ...

Dresselhaus, Mildred

386

Load Transfer Analysis in Short Carbon Fibers with Radially-Aligned Carbon Nanotubes Embedded in a Polymer Matrix  

E-Print Network (OSTI)

A novel shortfiber composite in which the microscopic advanced fiber reinforcements are coated with radially aligned carbon nanotubes (CNTs) is analyzed in this study. A shear-lag model is developed to analyze the load ...

Ray, M. C.

387

Flame retardancy effects of graphene nanoplatelet/carbon nanotube hybrid membranes on carbon fiber reinforced epoxy composites  

Science Conference Proceedings (OSTI)

Carbon nanotube/graphene nanoplatelet (MWCNT/GNP) hybrid membranes with lower liquid permeability and better barrier effect compared to MWCNT membranes were successfully synthesized by vacuum filtering. Their morphologies, water permeability, and pore ...

Dongxian Zhuo, Rui Wang, Lixin Wu, Yanhua Guo, Lin Ma, Zixiang Weng, Jinyu Qi

2013-01-01T23:59:59.000Z

388

Nucleation mechanisms of aromatic polyesters, PET, PBT, and PEN, on single-wall carbon nanotubes: early nucleation stages  

Science Conference Proceedings (OSTI)

Nucleation mechanisms of poly (ethylene terephthalate) (PET), poly (butylene terephthalate) (PBT), and poly (ethylene naphthalate) (PEN) on single-wall carbon nanotubes (SWNTs) are proposed, based on experimental evidence, theoretical epitaxy analysis, ...

Adriana Espinoza-Martínez, Carlos Avila-Orta, Víctor Cruz-Delgado, Oscar Olvera-Neria, Julio González-Torres, Francisco Medellín-Rodríguez

2012-01-01T23:59:59.000Z

389

Study of cytotoxic and genotoxic effects of hydroxyl-functionalized multiwalled carbon nanotubes on human pulmonary cells  

Science Conference Proceedings (OSTI)

Chemical functionalization of multiwalled carbon nanotubes (MWCNTs) increases their solubility, dispersion, and biological applications. Since there are only a few studies on the toxicity of functionalized MWCNTs, we investigated the cytotoxic and genotoxic-oxidative ...

Cinzia Lucia Ursini; Delia Cavallo; Anna Maria Fresegna; Aureliano Ciervo; Raffaele Maiello; Stefano Casciardi; Francesca Tombolini; Giuliana Buresti; Sergio Iavicoli

2012-01-01T23:59:59.000Z

390

Mechanical behavior of nanostructured hybrids based on poly(vinyl alcohol)/bioactive glass reinforced with functionalized carbon nanotubes  

Science Conference Proceedings (OSTI)

This study reports the synthesis and characterization of novel tridimensional porous hybrids based on PVA combined with bioactive glass and reinforced by chemically functionalized carbon nanotubes (CNT) for potential use in bone tissue engineering. The ...

H. S. Mansur, M. M. Pereira, H. S. Costa, A. A. P. Mansur

2012-01-01T23:59:59.000Z

391

Role of reaction and factors of carbon nanotubes growth in chemical Vapour decomposition process using methane: a highlight  

Science Conference Proceedings (OSTI)

One of the remarkable achievements in the field of nanotechnology is Carbon Nanotubes (CNT) synthesis. Since their discovery in 1991 by Iijima, CNTs have attracted much attention across the world. The CNTs are broadly classified into single-walled carbon ...

V. M. Sivakumar; Abdul Rahman Mohamed; Ahmad Zuhairi Abdullah; Siang-Piao Chai

2010-01-01T23:59:59.000Z

392

Electronic detection of molecules on the exterior and molecular transport through the interior of single walled carbon nanotubes  

E-Print Network (OSTI)

Single walled carbon nanotubes (SWNT) are unique materials with high surface to volume ratio and all atoms residing on the surface. Due to their tubular shape both exterior and interior of the SWNT are available for ...

Lee, Chang Young

2010-01-01T23:59:59.000Z

393

Synthesis, Activity and Durability of Pt Nanoparticles Supported on Multi-walled Carbon Nanotubes for Oxygen Reduction  

E-Print Network (OSTI)

Carbon nanotube supported metal nanoparticles (NPs) have attracted considerable attention due to their great potential for heterogeneous catalysis. In this paper, surfactant-free and well dispersed platinum (Pt) NPs supported ...

Massachusetts Institute of Technology. Dept. of Chemistry; Massachusetts Institute of Technology. Dept. of Mechanical Engineering; Massachusetts Institute of Technology. Dept. of Materials Science and Engineering; Sheng, Wenchao; Lee, Seung Woo; Crumlin, Ethan J.; Chen, Shuo; Shao-Horn, Yang

394

Growth mechanism of a hybrid structure consisting of a graphite layer on top of vertical carbon nanotubes  

Science Conference Proceedings (OSTI)

Graphene and carbon nanotubes (CNTs) are both carbon-basedmaterials with remarkable optical and electronic properties which, among others, may find applications as transparent electrodes or as interconnects inmicrochips, respectively. This work reports ...

Nicolo' Chiodarelli; Cigang Xu; Olivier Richard; Hugo Bender; Alexander Klekachev; Mike Cooke; Marc Heyns; Stefan De Gendt; Guido Groeseneken; Philippe M. Vereecken

2012-01-01T23:59:59.000Z

395

Biogenic formation of As-S nanotubes by diverse Shewanella strains  

SciTech Connect

Shewanella sp. strain HN-41 was previously shown to produce novel, photoactive, As-S nanotubes via the reduction of As(V) and S2O3 2* under anaerobic conditions. To determine if this ability was unique to this bacterium, 10 different Shewanella strains, including Shewanella sp. strain HN-41, Shewanella sp. strain PV-4, Shewanella alga BrY, Shewanella amazonensis SB2B, Shewanella denitrificans OS217, Shewanella oneidensis MR-1, Shewanella putrefaciens CN-32, S. putrefaciens IR-1, S. putrefaciens SP200, and S. putrefaciens W3-6-1, were examined for production of As-S nanotubes under standardized conditions. Of the 10 strains examined, three formed As-S nanotubes like those of strain HN-41. While Shewanella sp. strain HN-41 and S.putrefaciens CN-32 rapidly formed As-S precipitates in 7 days, strains S. alga BrY and S. oneidensis MR-1 reduced As(V) at a much lower rate and formed yellow As-S after 30 days. Electron microscopy, energy-dispersive X-ray spectroscopy, and extended X-ray absorption fine-structure spectroscopy analyses showed that the morphological and chemical properties of As-S formed by strains S. putrefaciens CN-32, S. alga BrY, and S. oneidensis MR-1 were similar to those previously determined for Shewanella sp. strain HN-41 As-S nanotubes. These studies indicated that the formation of As-S nanotubes is widespread among Shewanella strains and is closely related to bacterial growth and the reduction rate of As(V) and thiosulfate.

Jiang, Shenghua; Lee, Ji-Hoon; Kim, Min-Gyu; Myung, Nosang V.; Fredrickson, Jim K.; Sadowsky, Michael J.; Hur, Hor-Gil

2009-11-01T23:59:59.000Z

396

Molten Salt-Carbon Nanotube Thermal Energy Storage for Concentrating Solar Power Systems  

Office of Scientific and Technical Information (OSTI)

Molten Salt-Carbon Nanotube Thermal Energy Storage for Concentrating Solar Power Systems Molten Salt-Carbon Nanotube Thermal Energy Storage for Concentrating Solar Power Systems Final Report March 31, 2012 Michael Schuller, Frank Little, Darren Malik, Matt Betts, Qian Shao, Jun Luo, Wan Zhong, Sandhya Shankar, Ashwin Padmanaban The Space Engineering Research Center Texas Engineering Experiment Station Texas A&M University Abstract We demonstrated that adding nanoparticles to a molten salt would increase its utility as a thermal energy storage medium for a concentrating solar power system. Specifically, we demonstrated that we could increase the specific heat of nitrate and carbonate salts containing 1% or less of alumina nanoparticles. We fabricated the composite materials using both evaporative and air drying methods. We tested several thermophysical properties of the composite materials,

397

Induced fermionic current in toroidally compactified spacetimes with applications to cylindrical and toroidal nanotubes  

Science Conference Proceedings (OSTI)

The vacuum expectation value of fermionic current is evaluated for a massive spinor field in spacetimes with an arbitrary number of toroidally compactified spatial dimensions in the presence of a constant gauge field. By using the Abel-Plana type summation formula and the zeta-function technique we present the fermionic current in two different forms. Nontrivial topology of the background spacetime leads to the Aharonov-Bohm effect for the fermionic current induced by the gauge field. The current is a periodic function of the magnetic flux with the period equal to the flux quantum. In the absence of gauge field it vanishes for special cases of untwisted and twisted fields. Applications of general formulas to Kaluza-Klein type models and to cylindrical and toroidal carbon nanotubes are given. In the absence of magnetic flux the total fermionic current in carbon nanotubes vanishes, due to the cancellation of contributions from two different sublattices of the hexagonal lattice of graphene.

Bellucci, S. [INFN, Laboratori Nazionali di Frascati, Via Enrico Fermi 40, 00044 Frascati (Italy); Saharian, A. A.; Bardeghyan, V. M. [Department of Physics, Yerevan State University, 1 Alex Manoogian Street, 0025 Yerevan (Armenia)

2010-09-15T23:59:59.000Z

398

Embedding a carbon nanotube across the diameter of a solid state nanopore  

E-Print Network (OSTI)

A fabrication method for positioning and embedding a single-walled carbon nanotube (SWNT) across the diameter of a solid state nanopore is presented. Chemical vapor deposition (CVD) is used to grow SWNTs over arrays of focused ion beam (FIB) milled pores in a thin silicon nitride membrane. This typically yields at least one pore whose diameter is centrally crossed by a SWNT. The final diameter of the FIB pore is adjusted to create a nanopore of any desired diameter by atomic layer deposition (ALD), simultaneously embedding and insulating the SWNT everywhere but in the region that crosses the diameter of the final nanopore, where it remains pristine and bare. This nanotube-articulated nanopore is an important step towards the realization of a new type of detector for biomolecule sensing and electronic characterization, including DNA sequencing.

E. S. Sadki; S. Garaj; D. Vlassarev; J. A. Golovchenko; D. Branton

2013-08-05T23:59:59.000Z

399

High Energy Density Utracapacitors: Low-Cost, High Energy and Power Density, Nanotube-Enhanced Ultracapacitors  

Science Conference Proceedings (OSTI)

Broad Funding Opportunity Announcement Project: FastCAP is improving the performance of an ultracapacitor—a battery-like electronic device that can complement, and possibly even replace, an HEV or EV battery pack. Ultracapacitors have many advantages over conventional batteries, including long lifespans (over 1 million cycles, as compared to 10,000 for conventional batteries) and better durability. Ultracapacitors also charge more quickly than conventional batteries, and they release energy more quickly. However, ultracapacitors have fallen short of batteries in one key metric: energy density—high energy density means more energy storage. FastCAP is redesigning the ultracapacitor’s internal structure to increase its energy density. Ultracapacitors traditionally use electrodes made of irregularly shaped, porous carbon. FastCAP’s ultracapacitors are made of tiny, aligned carbon nanotubes. The nanotubes provide a regular path for ions moving in and out of the ultracapacitor’s electrode, increasing the overall efficiency and energy density of the device.

None

2010-04-01T23:59:59.000Z

400

Enhancing thermal conductivity of fluids with graphite nanoparticles and carbon nanotube  

DOE Patents (OSTI)

A fluid media such as oil or water, and a selected effective amount of carbon nanomaterials necessary to enhance the thermal conductivity of the fluid. One of the preferred carbon nanomaterials is a high thermal conductivity graphite, exceeding that of the neat fluid to be dispersed therein in thermal conductivity, and ground, milled, or naturally prepared with mean particle size less than 500 nm, and preferably less than 200 nm, and most preferably less than 100 nm. The graphite is dispersed in the fluid by one or more of various methods, including ultrasonication, milling, and chemical dispersion. Carbon nanotubes with graphitic structure is another preferred source of carbon nanomaterial, although other carbon nanomaterials are acceptable. To confer long term stability, the use of one or more chemical dispersants is preferred. The thermal conductivity enhancement, compared to the fluid without carbon nanomaterial, is proportional to the amount of carbon nanomaterials (carbon nanotubes and/or graphite) added.

Zhang, Zhiqiang (Lexington, KY); Lockwood, Frances E. (Georgetown, KY)

2008-03-25T23:59:59.000Z

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to obtain the most current and comprehensive results.


401

Fabrication of carbon nanotube films from alkyne-transition metal complexes  

DOE Patents (OSTI)

A simple method for the production or synthesis of carbon nanotubes as free-standing films or nanotube mats by the thermal decomposition of transition metal complexed alkynes with aryl, alkyl, alkenyl, or alkynyl substituents. In particular, transition metal (e.g. Co, Ni, Fe, Mo) complexes of diarylacetylenes, e.g. diphenylacetylene, and solid mixtures of these complexes with suitable, additional carbon sources are heated in a vessel. More specifically, the heating of the transition metal complex is completed at a temperature between 400-800.degree. C. and more particularly 550-700.degree. C. for between 0.1 to 24 hours and more particularly 0.5-3 hours in a sealed vessel under a partial pressure of argon or helium.

Iyer, Vivekanantan S. (Delft, NL); Vollhardt, K. Peter C. (Oakland, CA)

2007-08-28T23:59:59.000Z

402

Iron-Doped Carbon Aerogels: Novel Porous Substrates for Direct Growth of Carbon Nanotubes  

Science Conference Proceedings (OSTI)

We present the synthesis and characterization of Fe-doped carbon aerogels (CAs) and demonstrate the ability to grow carbon nanotubes directly on monoliths of these materials to afford novel carbon aerogel-carbon nanotube composites. Preparation of the Fe-doped CAs begins with the sol-gel polymerization of the potassium salt of 2,4-dihydroxybenzoic acid with formaldehyde, affording K{sup +}-doped gels that can then be converted to Fe{sup 2+}- or Fe{sup 3+}-doped gels through an ion exchange process, dried with supercritical CO{sub 2} and subsequently carbonized under an inert atmosphere. Analysis of the Fe-doped CAs by TEM, XRD and XPS revealed that the doped iron species are reduced during carbonization to form metallic iron and iron carbide nanoparticles. The sizes and chemical composition of the reduced Fe species were related to pyrolysis temperature as well as the type of iron salt used in the ion exchange process. Raman spectroscopy and XRD analysis further reveal that, despite the presence of the Fe species, the CA framework is not significantly graphitized during pyrolysis. The Fe-doped CAs were subsequently placed in a thermal CVD reactor and exposed to a mixture of CH{sub 4} (1000 sccm), H{sub 2} (500 sccm), and C{sub 2}H{sub 4} (20 sccm) at temperatures ranging from 600 to 800 C for 10 minutes, resulting in direct growth of carbon nanotubes on the aerogel monoliths. Carbon nanotubes grown by this method appear to be multiwalled ({approx}25 nm in diameter and up to 4 mm long) and grow through a tip-growth mechanism that pushes catalytic iron particles out of the aerogel framework. The highest yield of CNTs were grown on Fe-doped CAs pyrolyzed at 800 C treated at CVD temperatures of 700 C.

Steiner, S A; Baumann, T F; Kong, J; Satcher, J H; Dresselhaus, M S

2007-02-15T23:59:59.000Z

403

Thermodynamics of the formation of catalyst clusters for carbon nanotube growth  

SciTech Connect

A fundamental thermodynamic model of formation of catalyst clusters for growing carbon nanotubes has been developed and model predictions have been compared with the experimental data. An expression for the size distribution function of clusters, depending on the conditions of their formation, is obtained. It is shown that surface tension plays an important role in the cluster formation. The surface tension coefficient for iron clusters at 950 deg. C is determined.

Bulyarskii, S. V.; Pyatilova, O. V.; Tsygantsov, A. V. [Ulyanovsk State University (Russian Federation); Basaev, A. S.; Galperin, V. A., E-mail: V.Galperin@tcen.ru; Pavlov, A. A.; Shaman, Yu. P. [Moscow Institute of Electronic Engineering, Technology Center Research and Production Complex (Russian Federation)

2010-12-15T23:59:59.000Z

404

Iron-Doped Carbon Aerogels: Novel Porous Substrates for Direct Growth of Carbon Nanotubes  

DOE R&D Accomplishments (OSTI)

We present the synthesis and characterization of Fe-doped carbon aerogels (CAs) and demonstrate the ability to grow carbon nanotubes directly on monoliths of these materials to afford novel carbon aerogel-carbon nanotube composites. Preparation of the Fe-doped CAs begins with the sol-gel polymerization of the potassium salt of 2,4-dihydroxybenzoic acid with formaldehyde, affording K{sup +}-doped gels that can then be converted to Fe{sup 2+}- or Fe{sup 3+}-doped gels through an ion exchange process, dried with supercritical CO{sub 2} and subsequently carbonized under an inert atmosphere. Analysis of the Fe-doped CAs by TEM, XRD and XPS revealed that the doped iron species are reduced during carbonization to form metallic iron and iron carbide nanoparticles. The sizes and chemical composition of the reduced Fe species were related to pyrolysis temperature as well as the type of iron salt used in the ion exchange process. Raman spectroscopy and XRD analysis further reveal that, despite the presence of the Fe species, the CA framework is not significantly graphitized during pyrolysis. The Fe-doped CAs were subsequently placed in a thermal CVD reactor and exposed to a mixture of CH{sub 4} (1000 sccm), H{sub 2} (500 sccm), and C{sub 2}H{sub 4} (20 sccm) at temperatures ranging from 600 to 800 C for 10 minutes, resulting in direct growth of carbon nanotubes on the aerogel monoliths. Carbon nanotubes grown by this method appear to be multiwalled ({approx}25 nm in diameter and up to 4 mm long) and grow through a tip-growth mechanism that pushes catalytic iron particles out of the aerogel framework. The highest yield of CNTs were grown on Fe-doped CAs pyrolyzed at 800 C treated at CVD temperatures of 700 C.

Steiner, S. A.; Baumann, T. F.; Kong, J.; Satcher, J. H.; Dresselhaus, M. S.

2007-02-20T23:59:59.000Z

405

Program on Technology Innovation: Carbon Nanotube Technology for the Electric Power Industry  

Science Conference Proceedings (OSTI)

A couple decades ago, a new molecular form of carbon exhibiting extraordinary properties was discovered. This resulted in a frenzy of basic and applied research, and tremendous strides have been made. The technology that ensued is still relatively immature, but there is the prospect that the technology may be used in the future for a wide range of applications in the electric power industry. In fact, the three new materials discussed in this report (fullerenes, nanotubes, and graphene) have the potential...

2011-11-22T23:59:59.000Z

406

Lithium Doping of Single-Walled Carbon Nanotubes for Battery and Semiconductor Applications Kevin Donaher, Columbia University, Georgia Institute of Technology SURF 2010 Fellow  

E-Print Network (OSTI)

Lithium Doping of Single-Walled Carbon Nanotubes for Battery and Semiconductor Applications Kevin Jang, Mentor: Wonsang Koh Abstract The properties of lithium doped (5,5) metallic and (8 lithium binds to carbon nanotubes and how this affects the band structure of the semiconducting carbon

Li, Mo

407

Thermally-aware modeling and performance evaluation for single-walled carbon nanotube-based interconnects for future high performance integrated circuits  

Science Conference Proceedings (OSTI)

Given the performance and reliability limits of conventional copper interconnects in the tens of nanometer regime, carbon-nanotube (CNT) based interconnects emerge as a potential reliable alternative for future high performance VLSI industry. In this ... Keywords: Carbon nanotube bundles, High performance interconnect, Thermal modeling

Amir Hosseini; Vahid Shabro

2010-10-01T23:59:59.000Z

408

Strain rate effects in the mechanical response of polymer anchored carbon nanotube foams  

E-Print Network (OSTI)

Super-compressible foam-like carbon nanotube films have been reported to exhibit highly nonlinear viscoelastic behaviour in compression similar to soft tissue. Their unique combination of light weight and exceptional electrical, thermal and mechanical properties have helped identify them as viable building blocks for more complex nanosystems and as stand-alone structures for a variety of different applications. In the as-grown state, their mechanical performance is limited by the weak adhesion between the tubes, controlled by the van der Waals forces, and the substrate allowing the forests to split easily and to have low resistance in shear. Under axial compression loading carbon nanotubes have demonstrated bending, buckling8 and fracture9 (or a combination of the above) depending on the loading conditions and on the number of loading cycles. In this work, we partially anchor dense vertically aligned foam-like forests of carbon nanotubes on a thin, flexible polymer layer to provide structural stability, and report the mechanical response of such systems as a function of the strain rate. We test the sample under quasi-static indentation loading and under impact loading and report a variable nonlinear response and different elastic recovery with varying strain rates. A Bauschinger-like effect is observed at very low strain rates while buckling and the formation of permanent defects in the tube structure is reported at very high strain rates. Using high-resolution transmission microscopy

A. Misra; J. R. Greer; C. Daraio

2008-04-05T23:59:59.000Z

409

Structural stability of transparent conducting films assembled from length purified single-wall carbon nanotubes  

DOE Green Energy (OSTI)

Single-wall carbon nanotube (SWCNT) films show significant promise for transparent electronics applications that demand mechanical flexibility, but durability remains an outstanding issue. In this work, thin membranes of length purified single-wall carbon nanotubes (SWCNTs) are uniaxially and isotropically compressed by depositing them on prestrained polymer substrates. Upon release of the strain, the topography, microstructure, and conductivity of the films are characterized using a combination of optical/fluorescence microscopy, light scattering, force microscopy, electron microscopy, and impedance spectroscopy. Above a critical surface mass density, films assembled from nanotubes of well-defined length exhibit a strongly nonlinear mechanical response. The measured strain dependence reveals a dramatic softening that occurs through an alignment of the SWCNTs normal to the direction of prestrain, which at small strains is also apparent as an anisotropic increase in sheet resistance along the same direction. At higher strains, the membrane conductivities increase due to a compression-induced restoration of conductive pathways. Our measurements reveal the fundamental mode of elasto-plastic deformation in these films and suggest how it might be suppressed.

J. M. Harris; G. R. S. Iyer; D. O. Simien; J. A. Fagan; J. Y. Huh; J. Y. Chung; S. D. Hudson; J. Obrzut; J. F. Douglas; C. M. Stafford; E. K. Hobbie

2011-01-01T23:59:59.000Z

410

Structure and dynamics of water adsorbed in carbon nanotubes : a joint neutron scattering and molecular-dynamics study.  

DOE Green Energy (OSTI)

The advent of nanocarbons, from single- and multiple-walled nanotubes to nanohorns, avails model studies of confined molecules on the nanoscale. Water encapsulated inside the quasi-one-dimensional channels of these materials is expected to exhibit anomalous behavior due to the unique geometry of nanotubes and the weak interaction between the water molecules and the carbon atoms. We have employed neutron small-to-wide angle diffraction, quasielastic and inelastic scattering in conjunction with molecular-dynamics simulations to characterize the structures and dynamics of water adsorbed in open-ended single- and double-walled nanotubes over a wide range of spatial and temporal scales. We find that a square-ice sheet wrapped next to the inner nanotube wall and a water chain in the interior are the key structural elements of nanotube-confined water/ice. This configuration results in a hydrogen-bond connectivity that markedly differs from that in bulk water. This significantly softened hydrogen-bond network manifests in strong energy shifts of the observed and simulated inter- and intra-molecular vibrations. The very large mean-square displacement of hydrogen atoms observed experimentally and the strong anharmonicity inferred from simulations explain the fluid-like behavior at temperatures far below the freezing point of normal water.

de Souza, N. R.; Kolesnikov, A. I.; Loong, C.-K.; Moravsky, A. P.; Loutfy, R. O.; Burnham, C. J.; Intense Pulsed Neutron Source; MER Corp.; Univ. of Utah

2004-01-01T23:59:59.000Z

411

Preparation of a novel structured catalyst based on aligned carbon nanotube arrays for a microchannel Fischer-Tropsch synthesis reactor  

SciTech Connect

A novel catalyst microstructure based on aligned multiwall carbon nanotube arrays was synthesized. Its advanced heat and mass transport characteristics coupled with high surface area led to superior performances for Fischer-Tropsch synthesis in a microchannel chemical reactor. The fabrication of such a novel catalyst structure first involved metalorganic chemical vapor deposition (MOCVD) growth of a dense Al2O3 thin film over FeCrAlY foam substrate to enhance adhesion between catalyst layer and metal substrate. Aligned arrays of multiwall carbon nanotubes were grown over the substrate by catalytic decomposition of ethylene. These nanotube bundles were directly attached to the FeCrAlY substrate through a thin layer of oxide thin film. When the outer surfaces of nanobundles were coated with a catalyst layer, a unique hierarchical catalyst structure with nanoporous interstitials between the bundles was created. Thus, engineered catalysts based on such a novel hierarchical structure minimizes mass transfer encountered in the gas-liquid-solid three phase reactions. In addition, high thermal conductivity of carbon nanotube and the direct attachment of these nanobundles to the metal foam allow efficient heat removal from catalytic sites. The advanced heat and mass transfer on this novel structured catalyst was demonstrated in Fischer-Tropsch synthesis in a microchannel fixed bed reactor. The presence of carbon nanotube arrays improved dispersion of active metals and reduced mass transfer limitation, leading to a factor of four enhancement of Fischer-Tropsch synthesis activity. The improved temperature control with the carbon nanotube arrays also allows the Fischer-Tropsch synthesis being operated at temperatures as high as 265 C without reaction runaway favoring methane formation.

Chin, Ya-Huei; Hu, Jianli; Cao, Chunshe; Gao, Yufei; Wang, Yong

2005-12-15T23:59:59.000Z

412

Comparison of structural properties of pristine and gamma irradiated single-wall carbon nanotubes: Effects of medium and irradiation dose  

SciTech Connect

A systematic study of the gamma irradiation effects on single wall carbon nanotube (SWCNT) structure was conducted. Nanotubes were exposed to different doses of gamma irradiation in three media. Irradiation was carried out in air, water and aqueous ammonia. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and Raman spectroscopy confirmed the changes in the SWCNT structure. TGA measurements showed the highest percentage of introduced groups for the SWCNTs irradiated with 100 kGy. FTIR spectroscopy provided evidence for the attachment of hydroxyl, carboxyl and nitrile functional groups to the SWCNT sidewalls. Those groups were confirmed by EA. All irradiated SWCNTs had hydroxyl and carboxyl groups irrelevant to media used for irradiation, but nitrile functional groups were only identified in SWCNTs irradiated in aqueous ammonia. Raman spectroscopy indicated that the degree of disorder in the carbon nanotube structure correlates with the irradiation dose. For the nanotubes irradiated with the dose of 100 kGy, the Raman I{sub D}/I{sub G} ratio was three times higher than for the pristine ones. Atomic force microscopy showed a 50% decrease in nanotube length at a radiation dose of 100 kGy. Scanning and transmission electron microscopies showed significant changes in the morphology and structure of gamma irradiated SWCNTs. - Highlights: Black-Right-Pointing-Pointer Gamma irradiation causes SWCNT covalent functionalization. Black-Right-Pointing-Pointer Type of covalently attached groups to SWCNT surface depends on irradiation medium. Black-Right-Pointing-Pointer The SWCNT shortening level increases with applied irradiation dose. Black-Right-Pointing-Pointer The average length of carbon nanotubes decreased by 50% at the highest dose. Black-Right-Pointing-Pointer The diameter of SWCNT bundles becomes small as irradiation dose rises.

Kleut, D. [Vinca Institute of Nuclear Sciences, P.O.B. 522, University of Belgrade, 11001 Belgrade (Serbia)] [Vinca Institute of Nuclear Sciences, P.O.B. 522, University of Belgrade, 11001 Belgrade (Serbia); Jovanovic, S., E-mail: svetlanajovanovic@vinca.rs [Vinca Institute of Nuclear Sciences, P.O.B. 522, University of Belgrade, 11001 Belgrade (Serbia); Markovic, Z.; Kepic, D.; Tosic, D. [Vinca Institute of Nuclear Sciences, P.O.B. 522, University of Belgrade, 11001 Belgrade (Serbia)] [Vinca Institute of Nuclear Sciences, P.O.B. 522, University of Belgrade, 11001 Belgrade (Serbia); Romcevic, N. [Insitute of Physics, P.O.B. 68, University of Belgrade, 11001 Belgrade (Serbia)] [Insitute of Physics, P.O.B. 68, University of Belgrade, 11001 Belgrade (Serbia); Marinovic-Cincovic, M.; Dramicanin, M. [Vinca Institute of Nuclear Sciences, P.O.B. 522, University of Belgrade, 11001 Belgrade (Serbia)] [Vinca Institute of Nuclear Sciences, P.O.B. 522, University of Belgrade, 11001 Belgrade (Serbia); Holclajtner-Antunovic, I. [Faculty of Physical Chemistry, P.O.B. 47, University of Belgrade, 11158 Belgrade (Serbia)] [Faculty of Physical Chemistry, P.O.B. 47, University of Belgrade, 11158 Belgrade (Serbia); Pavlovic, V. [Faculty of Agriculture, P.O.B. 127, University of Belgrade, 11080 Belgrade (Serbia)] [Faculty of Agriculture, P.O.B. 127, University of Belgrade, 11080 Belgrade (Serbia); Drazic, G. [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)] [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Milosavljevic, M.; Todorovic Markovic, B. [Vinca Institute of Nuclear Sciences, P.O.B. 522, University of Belgrade, 11001 Belgrade (Serbia)] [Vinca Institute of Nuclear Sciences, P.O.B. 522, University of Belgrade, 11001 Belgrade (Serbia)

2012-10-15T23:59:59.000Z

413

Interaction of carbon dioxide laser radiation with a nanotube array in the presence of a constant electric field  

SciTech Connect

The dependence of the current density on the leading edge width of the alternating (high-frequency) field amplitude is studied at various constant (or unsteady) fields. The dependence of amplified microwaves in the two-millimeter range on a longitudinal coordinate is determined. The problem of submillimeter radiation generation in a system of parallel carbon nanotubes exposed to two-frequency carbon dioxide (CO{sub 2} laser) laser radiation in the presence of a constant (or unsteady) field is studied. The possibility of using freely oriented carbon nanotubes parallel to each other is shown.

Sadykov, N. R., E-mail: n.r.sadykov@rambler.ru [Branch of South Ural State University (Russian Federation); Scorkin, N. A. [Snezhinsk Physics and Technology Institute of the National Research Nuclear University 'MEPhI' (Russian Federation)

2012-06-15T23:59:59.000Z

414

Transparent and Conductive Carbon Nanotube Multilayer Thin Films Suitable as an Indium Tin Oxide Replacement  

E-Print Network (OSTI)

Transparent electrodes made from metal oxides suffer from poor flexibility and durability. Highly transparent and electrically conductive thin films based on carbon nanotubes (CNTs) were assembled as a potential indium tin oxide (ITO) replacement using layer-by-layer (LbL) assembly. The ultimate objective of this dissertation work is to produce CNT-based assemblies with sheet resistance below 100 Omega/sq and visible light transmission greater than 85 percent. The alternate deposition of positively charged poly(diallyldimethylammonium chloride) [PDDA] and CNTs stabilized with negatively charged deoxycholate (DOC) exhibit linear film growth and thin film properties can be precisely tuned. Ellipsometry, quartz crystal microbalance, and UV-vis were used to measure the growth of these films as a function of PDDA-CNT bilayers deposited, while TEM, SEM, and AFM were used to visualize the nanostructure of these films. Following a literature review describing potential ITO substitutes and LbL technology, the influence of CNT type on optoelectronic performance of LbL assemblies is described. Three different types of nanotubes were investigated: (1) multiwalled carbon nanotubes (MWNTs), (2) few-walled carbon nanotubes (FWNT), and (3) purified single-walled carbon nanotubes (SWNTs). SWNTs produced the most transparent (>85 percent visible light transmittance) and electrically conductive (148 S/cm, 1.62 kOmega/sq) 20-bilayer films with a 41.6 nm thickness, while MWNT-based films are much thicker and more opaque. A 20-bilayer PDDA/(MWNT DOC) film is approximately 103 nm thick, with a conductivity of 36 S/cm and a transmittance of 30 percent. In an effort to improve both transparency and electrical conductivity, heat and acid treatments were studied. Heating films to 300 degree C reduced sheet resistance to 701 Omega/sq (618 S/cm conductivity, 38.4 nm thickness), with no change in transparency, owing to the removal of insulating component in the film. Despite improving conductivity, heating is not compatible with most plastic substrates, so acid doping was investigated as an alternate means to enhance properties. Exposing SWNT-based assemblies to HNO3 vapor reduced sheet resistance of a 10 BL film to 227 Omega/sq. Replacing SWNTs with double walled carbon nanotubes (DWNTs) provided further reduction in sheet resistance due to the greater metallic of DWNT. A 5 BL DWNT film exhibited the lowest 104 Omega/sq sheet resistance (4200 S/cm conductivity, 22.9 nm thickness) with 84 percent transmittance after nitric acid treatment. DWNT-based assemblies maintained their low sheet resistance after repeated bending and also showed electrochemical stability relative to ITO. This work demonstrates the excellent optoelectronic performance, mechanical flexibility, and electrochemical stability of CNT-based assemblies, which are potentially useful as flexible transparent electrodes for a variety of flexible electronics.

Park, Yong Tae

2011-05-01T23:59:59.000Z

415

Carbon nanotube-induced preparation of vanadium oxide nanorods: Application as a catalyst for the partial oxidation of n-butane  

SciTech Connect

A vanadium oxide-carbon nanotube composite was prepared by solution-based hydrolysis of NH{sub 4}VO{sub 3} in the presence of carbon nanotubes. The carbon nanotubes induce the nucleation of the 1D vanadium oxide nanostructures, with the nuclei growing into long freestanding nanorods. The vanadium oxide nanorods with the lengths up to 20 {mu}m and the widths of 5-15 nm exhibit a well-ordered crystalline structure. Catalytic tests show that the composite with nanostructured vanadium oxide is active for the partial oxidation of n-butane to maleic anhydride at 300 deg. C.

Chen Xiaowei [Department of Inorganic Chemistry, Fritz-Haber-Institute of MPG, Faradayweg 4-6, D-14195 Berlin (Germany); Zhu Zhenping [Department of Inorganic Chemistry, Fritz-Haber-Institute of MPG, Faradayweg 4-6, D-14195 Berlin (Germany); Haevecker, Michael [Department of Inorganic Chemistry, Fritz-Haber-Institute of MPG, Faradayweg 4-6, D-14195 Berlin (Germany); Su Dangsheng [Department of Inorganic Chemistry, Fritz-Haber-Institute of MPG, Faradayweg 4-6, D-14195 Berlin (Germany)]. E-mail: dangsheng@fhi-berlin.mpg.de; Schloegl, Robert [Department of Inorganic Chemistry, Fritz-Haber-Institute of MPG, Faradayweg 4-6, D-14195 Berlin (Germany)

2007-02-15T23:59:59.000Z

416

Comparative Study of Ultimate Saturation Velocity in Zigzag and Chiral Carbon Nanotubes  

Science Conference Proceedings (OSTI)

Charge transfer mechanism in carbon nanotubes (CNTs) from the scattering-limited Ohmic transport to high-field-initiated ballistic transport is studied. It is shown that the electrons changes their motion from randomness (in equilibrium) to streamlined one (in non-equilibrium) when high electric field is applied. The intrinsic velocity is discussed in non-parabolic semiconducting limits considering the nondegenerate and degenerate situations. The results obtained are significant in extracting carrier transport properties from experimental data on CNTs and in understanding the fundamental processes controlling the charge transport in nanoscale devices.

Chek, Desmond C. Y.; Hashim, Abdul Manaf [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Tan, Michael Loong Peng [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Electrical Engineering Division, Engineering Department, University of Cambridge, 9 J.J. Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Arora, Vijay K. [Faculty of Electrical Eng., Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Division of Engineering and Physics, Wilkes University, Wilkes-Barre, PA 18766 (United States)

2011-05-25T23:59:59.000Z

417

Multifunctional nanocomposites of carbon nanotubes and nanoparticles formed via vacuum filtration  

Science Conference Proceedings (OSTI)

In one aspect, the present invention provides a method of forming a film of nanocomposites of carbon nanotubes (CNTs) and platinum (Pt) nanoparticles. In one embodiment, the method includes the steps of (a) providing a first solution that contains a plurality of CNTs, (b) providing a second solution that contains a plurality of Pt nanoparticles, (c) combining the first solution and the second solution to form a third solution, and (d) filtering the third solution through a nanoporous membrane using vacuum filtration to obtain a film of nanocomposites of CNTs and Pt nanoparticles.

Hersam, Mark C; Ostojic, Gordana; Liang, Yu Teng

2013-10-22T23:59:59.000Z

418

Synthesis of Ru/multiwalled carbon nanotubes by microemulsion for electrochemical supercapacitor  

Science Conference Proceedings (OSTI)

An efficient way to decorate multiwalled carbon nanotubes with Ru had been developed. In this method, Ru nanoparticles were prepared by water-in-oil reverse microemulsion, and the produced Ru anchored on MWCNTs. Transmission electron microscopy (TEM) result showed that RuO{sub 2} nanoparticles had the uniform size distribution after electrochemical oxidation. Energy dispersive X-rays (EDX) spectra elucidated the presence of ruthenium oxide in the as-prepared composites after electrochemical oxidation. Cyclic voltammetry result demonstrated that a specific capacitance of deposited ruthenium oxide electrode was significantly greater than that of the pristine MWCNTs electrode in the same medium.

Yan Shancheng; Qu Peng; Wang Haitao; Tian Tian [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Si Pai Lou 2, Nanjing 210096 (China); Xiao Zhongdang [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Si Pai Lou 2, Nanjing 210096 (China)], E-mail: zdxiao@seu.edu.cn

2008-10-02T23:59:59.000Z

419

Synthesis of Thermal Interface Materials Made of Metal Decorated Carbon Nanotubes and Polymers  

E-Print Network (OSTI)

This thesis describes the synthesis of a low modulus, thermally conductive thermal interface materials (TIM) using metal decorated nanotubes as fillers. TIMs are very important in electronics because they act as a thermally-conductive medium for thermal transfer between the interface of a heat sink and an electronic package. The performance of an electronic package decreases with increasing operating temperature, hence, there exists a need to create a TIM which has high thermal conduction to reduce the operating temperature. The TIM in this study is made from metal decorated multi-walled carbon nanotubes (MWCNT) and Vinnapas®BP 600 polymer. The sample was functionalized using mild oxidative treatment with nitric acid (HNO3) or, with N-Methly-2-Pyrrolidone (NMP). The metals used for this experiment were copper (Cu), tin (Sn), and nickel (Ni). The metal nanoparticles were seeded using functionalized MWCNTs as templates. Once seeded, the nanotubes and polymer composites were made with or without sodium dodecylbenzene sulfonate (SDBS), as a surfactant. Thermal conductivity (k) measurement was carried out using ASTM D-5470 method at room temperature. This setup best models the working conditions of a TIM. The TIM samples made for this study showed promise in their ability to have significant increase in thermal conduction while retaining the polymer’s mechanical properties. The highest k value that was obtained was 0.72 W/m-K for a well dispersed aligned 5 wt percent Ni@MWCNT sample. The Cu samples underperformed both Ni and Sn samples for the same synthesis conditions. This is because Cu nanoparticles were significantly larger than those of Ni and Sn. They were large enough to cause alloy scattering and too large to attach to the nanotubes. Addition of thermally-conductive fillers, such as exfoliated graphite, did not yield better k results as it sunk to the bottom during drying. The use of SDBS greatly increased the k values of the sample by reducing agglomeration. Increasing the amount of metal@MWCNT wt percent in the sample had negative or no effect to the k values. Shear testing on the sample shows it adheres well to the surface when pressure is applied, yet it can be removed with ease.

Okoth, Marion Odul

2010-08-01T23:59:59.000Z

420

Electronic Durability of Flexible Transparent Films from Type-Specific Single-Wall Carbon Nanotubes  

Science Conference Proceedings (OSTI)

The coupling between mechanical flexibility and electronic performance is evaluated for thin films of metallic and semiconducting single-wall carbon nanotubes (SWCNTs) deposited on compliant supports. Percolated networks of type-purified SWCNTs are assembled as thin conducting coatings on elastic polymer substrates, and the sheet resistance is measured as a function of compression and cyclic strain through impedance spectroscopy. The wrinkling topography, microstructure and transparency of the films are independently characterized using optical microscopy, electron microscopy, and optical absorption spectroscopy. Thin films made from metallic SWCNTs show better durability as flexible transparent conductive coatings, which we attribute to a combination of superior mechanical performance and higher interfacial conductivity.

Harris, J; Iyer, S; Bernhardt, A; Huh, JY; Hudson, S; Fagan, J; Hobbie, E.

2011-12-11T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Transparent Conductive Coating Based on Carbon Nanotubes Using Electric Field Deposition Method  

SciTech Connect

The transparent conductive coating based on carbon nanotubes (CNTs) had been fabricated using the electric field deposition method. The scanning electron microscope (SEM) results show a quite uniform CNTs on Corning glass substrates. Moreover the X-ray Diffraction (XRD) results shows the peak at around 25 deg. which proves the existence of CNT materials. The CNT thin films obtained with different deposition times have different transmittance coefficients at wavelength of 550 nm. I-V measurement results shows higher sheet resistance value which relates with bigger transmittance coefficients and vice versa.

Latununuwe, Altje [Physics of Electronic Materials Research Division, ITB, Jl. Ganesha No.10 Bandung (Indonesia); Department of Physics Education, Pattimura University, Jl. Ir.M.Putuhena Poka Ambon (Indonesia); Hattu, Nikmans [Chemistry Deparment, Pattimura University, Jl. Ir.M.Putuhena Poka Ambon (Indonesia); Setiawan, Andhy [Physics of Electronic Materials Research Division, ITB, Jl. Ganesha No.10 Bandung (Indonesia); Physics Department, Indonesia University of Education (UPI) Jl.Dr.Setiabudi No. 229, Bandung (Indonesia); Winata, Toto; Abdullah, Mikrajuddin; Darma, Yudi [Physics of Electronic Materials Research Division, ITB, Jl. Ganesha No.10 Bandung (Indonesia)

2010-10-24T23:59:59.000Z

422

Q1Report for CADWR Project: Desalination Using Carbon NAnotube Membranes  

Science Conference Proceedings (OSTI)

In this research and development project, LLNL will leverage the process for fabrication of the membranes developed by our internally funded effort (LLNL Laboratory Directed Research and Development). LLNL will then employ chemical manipulations to modify charge at the ends of the nanotubes and make the membranes more selective to either positive or negative ions through a combination of size and charge selectivity. LLNL's goal is to demonstrate ion exclusion while preserving high permeabilities and low energy use. Success of this research and development project may warrant further developments in the fabrication of membranes.

Bakajin, O

2008-05-14T23:59:59.000Z

423

Photoluminescence of samarium-doped TiO{sub 2} nanotubes  

SciTech Connect

Samarium (Sm)-modified TiO{sub 2} nanotubes (TNTs) were synthesized by low-temperature soft chemical processing. X-ray powder diffraction analyses of the synthesized Sm-doped and non-doped TNTs show a broad peak near 2{theta}=10{sup o}, which is typical of TNTs. The binding energy of Sm {sup 3}d{sub 5/2} for 10 mol% Sm-doped TNT (1088.3 eV) was chemically shifted from that of Sm{sub 2}O{sub 3} (1087.5 eV), showing that Sm existed in the TiO{sub 2} lattice. Sm-doped TNTs clearly exhibited red fluorescence, corresponding to the doped Sm{sup 3+} ion in the TNT lattice. The Sm-doped TNT excitation spectrum exhibited a broad curve, which was similar to the UV-vis optical absorption spectrum. Thus, it was considered that the photoluminescence emission of Sm{sup 3+}-doped TNT with UV-light irradiation was caused by the energy transfer from the TNT matrix via the band-to-band excitation of TiO{sub 2} to the Sm{sup 3+} ion. - Graphical Abstract: Samarium-doped TiO{sub 2} nanotubes (TNTs) having a nanotubular structure were synthesized by soft chemical route. It was revealed that the energy associated by the band-to-band excitation of TNT matrix transferred to the doped Sm{sup 3+} ions in the lattice, resulting in emission of strong and visible red fluorescence. Highlights: > Sm-doped TiO{sub 2} nanotubes synthesized by low-temperature soft chemical processing. > Sm{sup 3+} substitutes Ti{sup 4+} ions in the nanotube lattice. > Clear fluorescent emission due to the f-f transition at the Sm{sup 3+} in a crystal field environment. > Band-to-band excitation of TiO{sub 2} and followed energy transfer to Sm{sup 3+} causes the luminescence.

Park, Dong Jin [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Sekino, Tohru, E-mail: sekino@tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Tsukuda, Satoshi [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan); Hayashi, Asuka [Institute of Scientific and Industrial Research (ISIR), Osaka University, 8-1, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Kusunose, Takafumi [Faculty of Engineering, Kagawa University, Hayashi 2217-20, Takamatsu, Kagawa 761-0396 (Japan); Tanaka, Shun-Ichiro [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577 (Japan)

2011-10-15T23:59:59.000Z

424

The role of hydrogen in the growth of carbon nanotubes : a study of the catalyst state and morphology  

E-Print Network (OSTI)

The role of hydrogen in chemical vapor decomposition (CVD) of C2H4 for growth of carbon nanotubes (CNTs) was investigated. Fe/A1203 (1/10 nm) catalyst layers were used for growth on Si substrates and the times at which H2 ...

Kim, Jin Suk Calvin

2006-01-01T23:59:59.000Z

425

The Effect of Single Walled Carbon Nanotubes on Lithium-Ion Batteries and Electric Double Layer Capacitors  

E-Print Network (OSTI)

The Effect of Single Walled Carbon Nanotubes on Lithium- Ion Batteries and Electric Double Layer on the overall performance of Li-ion batteries and EDLCs. SWNTs were incorporated into the anode of the Lithium-ion is used because of its high surface area. Lithium-ion Batteries ·Higher energy density than other

Mellor-Crummey, John

426

Multisegmented Au-MnO2/Carbon Nanotube Hybrid Coaxial Arrays for High-Power Supercapacitor Applications  

E-Print Network (OSTI)

Multisegmented Au-MnO2/Carbon Nanotube Hybrid Coaxial Arrays for High-Power SupercapacitorVised Manuscript ReceiVed: NoVember 4, 2009 The present work reports on synthesis and supercapacitor applications hybrid coaxial arrays are efficient electrodes for supercapacitor applications. Au-segmented MnO2/CNT

Ajayan, Pulickel M.

427

Bonding and Stability of Hybrid Diamond/Nanotube O.A. SHENDEROVA*, D. ARESHKIN and D.W. BRENNER  

E-Print Network (OSTI)

Bonding and Stability of Hybrid Diamond/Nanotube Structures O.A. SHENDEROVA*, D. ARESHKIN and D.W precursors", Nature 364, 607. [6] Shenderova, O. and Brenner, D.W. (1997) "Coexistence of two carbon phases.T. and Brenner, D.W. (1997) "Mechanical Properties of nanotubule fibers and composites determined from

Brenner, Donald W.

428

Far-infrared gaps in single-wall carbon nanotubes A. Ugawa, A. G. Rinzler, and D. B. Tanner  

E-Print Network (OSTI)

the fraction of the tubes that have metallic or small band gap character. Second, we perform an effective of metallic tubes with m , 1 f is the volume fraction of semiconducting tubes with s , and g The infrared properties of single-wall carbon nanotubes have been measured over 15­5000 cm 1 . The sample

Tanner, David B.

429

A comparative study of three different chemical vapor deposition techniques of carbon nanotube growth on diamond films  

Science Conference Proceedings (OSTI)

This paper compares between the methods of growing carbon nanotubes (CNTs) on diamond substrates and evaluates the quality of the CNTs and the interfacial strength. One potential application for these materials is a heat sink/spreader for high-power ...

Betty T. Quinton, Paul N. Barnes, Chakrapani V. Varanasi, Jack Burke, Bang-Hung Tsao, Kevin J. Yost, Sharmila M. Mukhopadhyay

2013-01-01T23:59:59.000Z

430

Raman spectroscopic study of carbon nanotubes prepared using Fe/ZnO-palm olein-chemical vapour deposition  

Science Conference Proceedings (OSTI)

Multiwalled carbon nanotubes (MWCNTs) were synthesized using Fe/ZnO catalyst by a dual-furnace thermal chemical vapor deposition (CVD) method at 800-1000°C using nitrogen gas with a constant flow rate of 150 sccm/min as a gas carrier. Palm olein ...

Syazwan Afif Mohd Zobir; Suriani Abu Bakar; Saifollah Abdullah; Zulkarnain Zainal; Siti Halimah Sarijo; Mohamad Rusop

2012-01-01T23:59:59.000Z

431

A scattered data approximation tool to map single-walled carbon nanotube dispersion to the processing parameters in polymer nanocomposites  

Science Conference Proceedings (OSTI)

The relationship of nanocomposite dispersion to dispersion techniques and other processing parameters was studied. Examining all permutations of the various factors in the laboratory is a challenging task. In this paper, we propose to map a correlation ... Keywords: CNTs, RBF, carbon nanotubes, classification, dispersion, feature selection, functional mapping, greedy algorithms, nanotechnology, polymer nanocomposites, polymer processing, radial basis function, scattered data approximation, sequential function approximation

Jonathan W. Lee; Andrew J. Meade; Enrique V. Barrera

2010-08-01T23:59:59.000Z

432

Narrow (n,m)-Distribution of Single-Walled Carbon Nanotubes Grown Using a Solid Supported Catalyst  

E-Print Network (OSTI)

and carbon nanotubes occurs on unsupported iron catalyst clusters formed in situ by the gas- phase was centrifuged for 1 h at 72 600g to separate metallic catalyst particles and suspended tube bundles from at the bottom of the centrifuge tube. Finally, the supernatant liquid, enriched in individual surfactant

Resasco, Daniel

433

Syngas Segregation Induced by Confinement in Carbon Nanotubes: A Combined First-Principles and Monte Carlo Study  

E-Print Network (OSTI)

Syngas Segregation Induced by Confinement in Carbon Nanotubes: A Combined First of the concave and convex surfaces of CNTs formed by graphene layers. As a result, syngas molecules are enriched of CO/H2 inside CNTs increases with respect to the composition of syngas in the exterior gas phase

Bao, Xinhe

434

The Structure of Ions near Carbon Nanotubes: New Insights into Carbon  

NLE Websites -- All DOE Office Websites (Extended Search)

The Structure of Ions near Carbon Nanotubes: New Insights into The Structure of Ions near Carbon Nanotubes: New Insights into Carbon Surface Chemistry and Implications for Water Purification Carbon-based materials have long been used for a variety of water purification operations. Researchers have investigated carbon materials as adsorbents for decades, but only limited information on the precise details of aqueous ion interactions with carbon surfaces has been uncovered. It is empirically known that the affinity of activated carbon for various hydrated ions depends critically on how the material is processed. Processing influences the types of chemical groups and the structure of the carbon surface, which in turn influences the strength of interaction between hydrated ions and the carbon surface. It is also believed that many of the puzzling properties of impurity-free carbon, such as ferromagnetism, are governed by specific modifications of the carbon surface. However, very little is known about the local structure of the carbon surface that is responsible for its aqueous ion affinity.

435

Induced fermionic current in toroidally compactified spacetimes with applications to cylindrical and toroidal nanotubes  

E-Print Network (OSTI)

The vacuum expectation value of the fermionic current is evaluated for a massive spinor field in spacetimes with an arbitrary number of toroidally compactified spatial dimensions in presence of a constant gauge field. By using the Abel-Plana type summation formula and the zeta function technique we present the fermionic current in two different forms. Non-trivial topology of the background spacetime leads to the Aharonov-Bohm effect on the fermionic current induced by the gauge field. The current is a periodic function of the magnetic flux with the period equal to the flux quantum. In the absence of the gauge field it vanishes for special cases of untwisted and twisted fields. Applications of the general formulae to Kaluz-Klein type models and to cylindrical and toroidal carbon nanotubes are given. In the absence of magnetic flux the total fermionic current in carbon nanotubes vanishes, due to the cancellation of contributions from two different sublattices of the graphene hexagonal lattice.

S. Bellucci; A. A. Saharian; V. M. Bardeghyan

2010-02-08T23:59:59.000Z

436

Mechanism of Synthesis of Ultra-Long Single Wall Carbon Nanotubes in Arc Discharge Plasma  

SciTech Connect

In this project fundamental issues related to synthesis of single wall carbon nanotubes (SWNTs), which is relationship between plasma parameters and SWNT characteristics were investigated. Given that among plasma-based techniques arc discharge stands out as very advantageous in several ways (fewer defects, high flexibility, longer lifetime) this techniques warrants attention from the plasma physics and plasma technology standpoint. Both experimental and theoretical investigations of the plasma and SWNTs synthesis were conducted. Experimental efforts focused on plasma diagnostics, measurements of nanostructures parameters, and nanoparticle characterization. Theoretical efforts focused to focus on multi-dimensional modeling of the arc discharge and single wall nanotube synthesis in arc plasmas. It was demonstrated in experiment and theoretically that controlling plasma parameters can affect nanostucture synthesis altering SWNT properties (length and diameter) and leading to synthesis of new structures such as a few-layer graphene. Among clearly identified parameters affecting synthesis are magnetic and electric fields. Knowledge of the plasma parameters and discharge characteristics is crucial for ability to control synthesis process by virtue of both magnetic and electric fields. New graduate course on plasma engineering was introduced into curriculum. 3 undergraduate students were attracted to the project and 3 graduate students (two are female) were involved in the project. Undergraduate student from Historically Black University was attracted and participated in the project during Summer 2010.

Keidar, Michael [George Washington University] [George Washington University

2013-06-23T23:59:59.000Z

437

One-pot, high-yield synthesis of titanate nanotube bundles decorated by Pd (Au) clusters for stable electrooxidation of methanol  

Science Conference Proceedings (OSTI)

Titanate nanotube bundles assembled by several simple nanotubes were synthesized through a simple reaction between TiO{sub 2} crystallites and highly concentrated NaOH in the presence of Au or Pd sols. Due to the unique scrolling growth mechanism of titanate nanotubes (TNTs), Au or Pd clusters were encapsulated in situ by TNTs, and titanate/Au and titanate/Pd nanotube bundles were formed. In comparison with carbon nanotubes (CNTs) or active carbon that was widely used as carriers to support metal clusters, TNTs bundles can immobilize the metal clusters tightly and overcome the shortcoming of exfoliation of metal clusters from the carriers. The as-prepared titanate/metal hybrids possess mesoporosity and high surface area. The electrochemical oxidation of methanol demonstrates that titanate/Pd hybrids exhibit high electrocatalytic activity and excellent stability, and hence they should be ideal catalyst candidates in direct methanol fuel cells (DMFCs). - Graphical abstract: Titanate/Au and titanate/Pd nanotube bundles have been fabricated by taking advantage of the unique scrolling growth mechanism of titanate tubes. The titanate/Pd hybrids show stable catalytic effects toward the electrooxidation of methanol.

Xue Xiudong [Key Lab of Organic Synthesis of Jiangsu Province and Department of Chemistry, Soochow University, Suzhou, Jiangsu 215123 (China); Gu Li [College of Biology and Chemical Engineering, Jiaxing University, Jiaxing, Zhejiang 314001 (China); Cao Xuebo, E-mail: xbcao@suda.edu.c [Key Lab of Organic Synthesis of Jiangsu Province and Department of Chemistry, Soochow University, Suzhou, Jiangsu 215123 (China); Song Yingying; Zhu Lianwen; Chen Peng [Key Lab of Organic Synthesis of Jiangsu Province and Department of Chemistry, Soochow University, Suzhou, Jiangsu 215123 (China)

2009-10-15T23:59:59.000Z

438

SYNTHESIS AND CHARACTERIZATION OF CARBON AEROGEL NANOCOMPOSITES CONTAINING DOUBLE-WALLED CARBON NANOTUBES  

DOE Green Energy (OSTI)

Carbon aerogels (CAs) are novel mesoporous materials with applications such as electrode materials for super capacitors and rechargeable batteries, adsorbents and advanced catalyst supports. To expand the potential application for these unique materials, recent efforts have focused on the design of CA composites with the goal of modifying the structure, conductivity or catalytic activity of the aerogel. Carbon nanotubes (CNTs) possess a number of intrinsic properties that make them promising materials in the design of composite materials. In addition, the large aspect ratios (100-1000) of CNTs means that small additions (less than 1 vol%) of CNTs can produce a composite with novel properties. Therefore, the homogeneous incorporation of CNTs into a CA matrix provides a viable route to new carbon-based composites with enhanced thermal, electrical and mechanical properties. One of the main challenges in preparing CNT composites is achieving a good uniform dispersion of nanotubes throughout the matrix. CAs are typically prepared through the sol-gel polymerization of resorcinol with formaldehyde in aqueous solution to produce organic gels that are supercritically dried and subsequently pyrolyzed in an inert atmosphere. Therefore, a significant issue in fabricating CA-CNT composites is dispersing the CNTs in the aqueous reaction media. Previous work in the design of CACNT composites have addressed this issue by using organic solvents in the sol-gel reaction to facilitate dispersion of the CNTs. To our knowledge, no data has been published involving the preparation of CA composites containing CNTs dispersed in aqueous media. In this report, we describe a new method for the synthesis of monolithic CA-CNT composites that involves the sol-gel polymerization of resorcinol and formaldehyde in an aqueous solution containing a surfactant-stabilized dispersion of double-walled carbon nanotubes (DWNT). One of the advantages of this approach is that it allows one to uniformly distribute CNTs in the CA matrix without compromising the synthetic control that is afforded by traditional organic sol-gel chemistry over the CA structure. We will describe the physical characterization of these novel materials as well as the influence of DWNT loading on the electrical conductivity of the CA composite.

Worsley, M A; Satcher, J H; Baumann, T F

2008-03-11T23:59:59.000Z

439

Transition-Metal Strings Templated on Boron-Doped Carbon Nanotubes: A DFT Investigation  

SciTech Connect

The binding nature, magnetic, and electronic properties of transition-metal (TM) monatomic chains anchored on boron-doped single-walled carbon nanotubes (B-SWCNTs) are studied using density-functional theory. The TM systems studied here include Au, Pt, Ru, Pd, Ag, Co, Ni, Cu, W, and Ti, which are well-known for their technical importance. In conjunction, prototype semiconducting SWCNT(8,0) and metallic SWCNT(6,6) were chosen to model the general features of B-doped SWCNTs. It is found that the TM-strings exhibit well-defined covalent bonds with the boron-doped SWCNTs, in contrast to the pristine SWCNTs. The TMstring/ B-SWCNT composites exhibit high stability and unexpected electronic properties, which are relevant to applications in nanoelectronics, spintronics, nanocatalysis, and sensor devices.

An, Wei; Turner, C. H.

2009-08-27T23:59:59.000Z

440

Coherent exciton dynamics in supramolecular light-harvesting nanotubes revealed by ultrafast quantum process tomography  

E-Print Network (OSTI)

Long-lived exciton coherences have been recently observed in photosynthetic complexes via ultrafast spectroscopy, opening exciting possibilities for the study and design of coherent exciton transport. Yet, ambiguity in the spectroscopic signals has led to arguments for interpreting them in terms of the exciton dynamics, demanding more stringent tests. We propose a novel strategy, Quantum Process Tomography (QPT) for ultrafast spectroscopy, to reconstruct the evolving quantum state of excitons in double-walled supramolecular light-harvesting nanotubes at room temperature. The protocol calls for eight transient grating experiments with varied pulse spectra. Our analysis reveals unidirectional energy transfer from the outer to the inner wall excitons, absence of nonsecular processes, and an unexpected coherence between those two states lasting about 150 femtoseconds, indicating weak electronic coupling between the walls. Our work constitutes the first experimental QPT in a 'warm' and complex system, and provides an elegant scheme to maximize information from ultrafast spectroscopy experiments.

Joel Yuen-Zhou; Dylan H. Arias; Dorthe M. Eisele; Colby P. Steiner; Jacob J. Krich; Moungi Bawendi; Keith A. Nelson; Alán Aspuru-Guzik

2013-08-19T23:59:59.000Z

Note: This page contains sample records for the topic "nanotube umbilicals pnus" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Orientational order of carbon nanotube guests in a nematic host suspension of colloidal viral rods  

E-Print Network (OSTI)

In order to investigate the coupling between the degrees of alignment of elongated particles in binary nematic dispersions, surfactant stabilized single-wall carbon nanotubes (CNTs) have been added to nematic suspensions of colloidal rodlike viruses in aqueous solution.We have independently measured the orientational order parameter of both components of the guest-host system by means of polarized Raman spectroscopy and by optical birefringence, respectively. Our system allows us therefore to probe the regime where the guest particles (CNTs) are shorter and thinner than the fd virus host particles. We show that the degree of order of the CNTs is systematically smaller than that of the fd virus particles for the whole nematic range. These measurements are in good agreement with predictions of an Onsager-type second-viral theory, which explicitly includes the flexibility of the virus particles, and the polydispersity of the CNTs.

Nicolas Puech; Matthew Dennison; Christophe Blanc; Paul van der Schoot; Marjolein Dijkstra; René van Roij; Philippe Poulin; Eric Grelet

2013-06-23T23:59:59.000Z

442

Nano-sized Lithium Manganese Oxide Dispersed on Carbon Nanotubes for Energy Storage Applications  

Science Conference Proceedings (OSTI)

Nano-sized lithium manganese oxide (LMO) dispersed on carbon nanotubes (CNT) has been synthesized successfully via a microwave-assisted hydrothermal reaction at 200 C for 30 min using MnO{sub 2}-coated CNT and an aqueous LiOH solution. The initial specific capacity is 99.4 mAh/g at a 1.6 C-rate, and is maintained at 99.1 mAh/g even at a 16 C-rate. The initial specific capacity is also maintained up to the 50th cycle to give 97% capacity retention. The LMO/CNT nanocomposite shows excellent power performance and good structural reversibility as an electrode material in energy storage systems, such as lithium-ion batteries and electrochemical capacitors. This synthetic strategy opens a new avenue for the effective and facile synthesis of lithium transition metal oxide/CNT nanocomposite.

Bak, S.B.

2009-08-01T23:59:59.000Z

443

Neutron-Rich Isotope Production Using a Uranium Carbide Carbon Nanotubes SPES Target Prototype  

SciTech Connect

The SPES (Selective Production of Exotic Species) project, under development at the Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro (INFN-LNL), is a new-generation Isotope Separation On-Line (ISOL) facility for the production of radioactive ion beams by means of the proton-induced fission of uranium. In the framework of the research on the SPES target, seven uranium carbide discs, obtained by reacting uranium oxide with graphite and carbon nanotubes, were irradiated with protons at the Holifield Radioactive Ion Beam Facility (HRIBF) of Oak Ridge National Laboratory (ORNL). In the following, the yields of several fission products obtained during the experiment are presented and discussed. The experimental results are then compared to those obtained using a standard uranium carbide target. The reported data highlights the capability of the new type of SPES target to produce and release isotopes of interest for the nuclear physics community.

Corradetti, Stefano [ORNL; Biasetto, Lisa [INFN, Laboratori Nazionali di Legnaro, Italy; Manzolaro, Mattia [INFN, Laboratori Nazionali di Legnaro, Italy; Scarpa, Daniele [ORNL; Carturan, S. [INFN, Laboratori Nazionali di Legnaro, Italy; Andrighetto, Alberto [INFN, Laboratori Nazionali di Legnaro, Italy; Prete, Gianfranco [ORNL; Vasquez, Jose L [ORNL; Zanonato, P. [Dipartimento di Scienze Chimiche, Padova, Italy; Colombo, P. [Dipartimento di Ingegneria Meccanica, Padova, Italy; Jost, Carola [University of Tennessee, Knoxville (UTK); Stracener, Daniel W [ORNL

2013-01-01T23:59:59.000Z

444

Tailoring properties of carbon-nanotube-based foams by ion bombardment  

SciTech Connect

Particle irradiation is an effective method for manipulating properties of individual carbon nanotubes (CNTs). This potential, however, remains unexplored for macroscopic assemblies of cross-linked CNTs. Here, we study structural and electrical properties of ultralow-density cross-linked CNT-based nanofoams exposed to ion irradiation at room temperature over a wide range of ion masses and fluences. For all irradiation conditions studied, the electrical resistance of nanofoams initially increases with a rate that scales with the number of ballistically generated displacements. This process is attributed to the buildup of defects in graphitic nanoligaments. Irradiation with Ne and heavier ions leads to a decrease in the electrical resistance at large fluences, which is attributed to radiation-induced foam densification. In addition, heavy-ion bombardment causes amorphization of CNTs and smoothing of ligament surfaces. These results demonstrate that ion bombardment can be used for tailoring density, ligament morphology, and electrical properties of CNT-based foams.

Charnvanichborikarn, S.; Shin, S. J.; Worsley, M. A.; Kucheyev, S. O. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2012-09-03T23:59:59.000Z

445

Methane storage in multi-walled carbon nanotubes at the quantity of 80 g  

SciTech Connect

Methane storage in multi-walled carbon nanotubes (MWNTs) is studied at ambient temperature and pressures of 0-10.5 MPa, with a quantity of 80 g samples that were synthesized by nano-agglomerate fluidized-bed reactors (NAFBR). The volume of methane released by MWNTs was measured by volumetric method. We study the effects of purification and the pretreatments on methane storage. Results show that mixed acid treatment, alkali treatment, and mechanical shearing can obviously enhance gas uptake while high-temperature treatment can only slightly reduce it. For properly pretreated samples, an optimal 11.7% of mass storage capacity was achieved at room temperature and the pressure of 10.5 MPa, indicating that CNTs is a potential material for methane uptake.

Wu Yulong [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Wei Fei [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)], E-mail: wf-dce@tsinghua.edu.cn; Luo Guohua; Ning Guoqing [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China); Yang Mingde [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

2008-06-03T23:59:59.000Z

446

A carbon nanotube field emission multipixel x-ray array source for microradiotherapy application  

Science Conference Proceedings (OSTI)

The authors report a carbon nanotube (CNT) field emission multipixel x-ray array source for microradiotherapy for cancer research. The developed multipixel x-ray array source has 50 individually controllable pixels and it has several distinct advantages over other irradiation source including high-temporal resolution (millisecond level), the ability to electronically shape the form, and intensity distribution of the radiation fields. The x-ray array was generated by a CNT cathode array (5x10) chip with electron field emission. A dose rate on the order of >1.2 Gy/min per x-ray pixel beam is achieved at the center of the irradiated volume. The measured dose rate is in good agreement with the Monte Carlo simulation result.

Wang Sigen [Department of Radiation Oncology, University of North Carolina at Chapel Hill, North Carolina 27599 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, North Carolina 27599 (United States); Calderon, Xiomara; Peng Rui [Curriculum of Applied and Materials Sciences, University of North Carolina at Chapel Hill, North Carolina 27599 (United States); Schreiber, Eric C. [Department of Radiation Oncology, University of North Carolina at Chapel Hill, North Carolina 27599 (United States); Zhou, Otto [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, North Carolina 27599 (United States); Curriculum of Applied and Materials Sciences, University of North Carolina at Chapel Hill, North Carolina 27599 (United States); Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, North Carolina 27599 (United States); Chang, Sha [Department of Radiation Oncology, University of North Carolina at Chapel Hill, North Carolina 27599 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, North Carolina 27599 (United States); Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, North Carolina 27599 (United States)

2011-05-23T23:59:59.000Z

447

Carbon nanotube based microfocus field emission x-ray source for microcomputed tomography  

Science Conference Proceedings (OSTI)

Microcomputed tomography is now widely used for in vivo small animal imaging for cancer studies. Achieving high imaging quality of live objects requires the x-ray source to have both high spatial and temporal resolutions. Preliminary studies have shown that carbon nanotube (CNT) based field emission x-ray source has significant intrinsic advantages over the conventional thermionic x-ray tube including better temporal resolution and programmability. Here we report the design and characterization of a CNT based field emission x-ray source that also affords a high spatial resolution. The device uses modified asymmetric Einzel lenses for electron focusing and an elliptical shaped CNT cathode patterned by photolithography. Stable and small isotropic x-ray focal spot sizes were obtained.

Liu Zejian; Yang Guang; Lee, Yueh Z.; Bordelon, David; Lu Jianping; Zhou, Otto [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Curriculum in Applied and Materials Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 (United States); Department of Physics and Astronomy, University of North Carolina, Chapel Hill, North Carolina 27599 and Curriculum in Applied and Materials Sciences, University of North Carolina, Chapel Hill, North Carolina 27599 (United States)

2006-09-04T23:59:59.000Z

448

N-Type Thermoelectric Performance of Functionalized Carbon Nanotube-Filled Polymer Composites  

E-Print Network (OSTI)

Carbon nanotubes were dispersed and functionalized with polyethylene imine (PEI) before incorporation in a polyvinyl acetate matrix. The resulting samples exhibit air-stable N-type characteristics with electrical conductivities as great as 1600 S/m and thermopowers as high as 100 microV/K. Thermopowers and electrical conductivities correlate, in a reversal of the trend found in typical materials. This phenomenon is believed to be due to the increase in the number of tubes that are evenly coated in a better dispersed sample. Increasing the amount of PEI relative to the other constituents positively affects thermopower but not conductivity. Air exposure reduces both thermopower and conductivity, but a stable value is reached within seven days following film fabrication. The atmospheric effects on the electrical conductivity prove to be reversible. Oxygen is believed to be the primary contributor to the decay.

Freeman, Dallas

2012-05-01T23:59:59.000Z

449

Periodic alignment of Si quantum dots on hafnium oxide coated single wall carbon nanotubes  

SciTech Connect

We demonstrate a bottom up approach for the aligned epitaxial growth of Si quantum dots (QDs) on one-dimensional (1D) hafnium oxide (HfO{sub 2}) ridges created by the growth of HfO{sub 2} thin film on single wall carbon nanotubes. This growth process creates a high strain 1D ridge on the HfO{sub 2} film, which favors the formation of Si seeds over the surrounding flat HfO{sub 2} area. Periodic alignment of Si QDs on the 1D HfO{sub 2} ridge was observed, which can be controlled by varying different growth conditions, such as growth temperature, growth time, and disilane flow rate.

Olmedo, Mario; Martinez-Morales, Alfredo A.; Ozkan, Mihrimah; Liu Jianlin [Department of Electrical Engineering, University of California, Riverside, California 92521 (United States); Liu Gang; Lau, C.N. [Department of Physics and Astronomy, University of California, Riverside, California 92521 (United States); Yengel, Emre; Ozkan, Cengiz S. [Department of Mechanical Engineering, University of California, Riverside, California 92521 (United States)

2009-03-23T23:59:59.000Z

450

Six Thousand Electrochemical Cycles of Double-Walled Silicon Nanotube Anodes for Lithium Ion Batteries  

DOE Green Energy (OSTI)

Despite remarkable progress, lithium ion batteries still need higher energy density and better cycle life for consumer electronics, electric drive vehicles and large-scale renewable energy storage applications. Silicon has recently been explored as a promising anode material for high energy batteries; however, attaining long cycle life remains a significant challenge due to materials pulverization during cycling and an unstable solid-electrolyte interphase. Here, we report double-walled silicon nanotube electrodes that can cycle over 6000 times while retaining more than 85% of the initial capacity. This excellent performance is due to the unique double-walled structure in which the outer silicon oxide wall confines the inner silicon wall to expand only inward during lithiation, resulting in a stable solid-electrolyte interphase. This structural concept is general and could be extended to other battery materials that undergo large volume changes.

Wu, H

2011-08-18T23:59:59.000Z

451

Novel Carbon Nanotube-Based Nanostructures for High-Temperature Gas Sensing  

DOE Green Energy (OSTI)

The primary objective of this research is to examine the feasibility of using vertically aligned multi-wall carbon nanotubes (MWCNTs) as a high temperature sensor material for fossil energy systems where reducing atmospheres are present. In the initial period of research, we fabricated capacitive sensors for hydrogen sensing using vertically aligned MWCNTs. We found that CNT itself is not sensitive to hydrogen. Moreover, with the help of Pd electrodes, hydrogen sensors based on CNTs are very sensitive and fast responsive. However, the Pd-based sensors can not withstand high temperature (T<200 C). In the last year, we successfully fabricated a hydrogen sensor based on an ultra-thin nanoporous titanium oxide (TiO{sub 2}) film supported by an AAO substrate, which can operate at 500 C with hydrogen concentrations in a range from 50 to 500 ppm.

Zhi Chen; Kozo Saito

2008-08-31T23:59:59.000Z

452

Effects of deformation on the electronic properties of B-C-N nanotubes  

SciTech Connect

We apply first-principles methods, using density functional theory, to investigate the effects of flattening deformation on the electronic properties of BC{sub 2}N and C-doped BNNTs. Four different types of BC{sub 2}N structures are considered. Two of them are semiconductors, and the radial compression produces a significant reduction of the energy band gap. The other two types of structures are metallic, and the effect of radial compression is quite distinct. For one of them it is found the opening of a small band gap, and for the other one no changes are observed. For C-doped tubes, it is also found that the electronic properties undergo significant modifications when subjected to radial compression. - Graphical Abstract: We apply first-principles methods, using density functional theory, to investigate the effects of flattening deformation on the electronic properties of BC{sub 2}N and C-doped BNNTs. Four different types of BC{sub 2}N structures are considered. Two of them are semiconductors, and the radial compression produces a significant reduction of the energy band gap. The other two types of structures are metallic, and the effect of radial compression is quite distinct. For one of them it is found the opening of a small band gap, and for the other one no changes are observed. For C-doped tubes, it is also found that the electronic properties undergo significant modifications when subjected to radial compression. Highlights: Black-Right-Pointing-Pointer We investigated electronic properties of flattened BC{sub 2}N nanotubes. Black-Right-Pointing-Pointer The electronic states depend strongly on compression. Black-Right-Pointing-Pointer It is studied flattened BN nanotubes doped with a carbon atom. Black-Right-Pointing-Pointer The flattened C-doped structures, presents a significant reduction of the gap.

Azevedo, S., E-mail: sazevedo@fisica.ufpb.br [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58059-900 Joao Pessoa-PB (Brazil); Rosas, A. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, 58059-900 Joao Pessoa-PB (Brazil); Machado, M. [Departamento de Fisica, Universidade Federal de Pelotas, Caixa Postal 354, 96010-900 Pelotas-RS (Brazil); Kaschny, J.R. [Instituto Federal da Bahia-Campus Vitoria da Conquista, Av. Amazonas 3150, 45030-220 Vitoria da Conquista-BA (Brazil); Chacham, H. [Departamento de Fisica, ICEX, Universidade Federal de Minas Gerais, Caixa Postal 702, 30123-970 Belo Horizonte-MG (Brazil)

2013-01-15T23:59:59.000Z

453

Nanostructured Electrodes For Organic Bulk Heterojunction Solar Cells: Model Study Using Carbon Nanotube Dispersed Polythiophene-fullerene Blend Devices  

Science Conference Proceedings (OSTI)

We test the feasibility of using nanostructured electrodes in organic bulk heterojunction solar cells to improve their photovoltaic performance by enhancing their charge collection efficiency and thereby increasing the optimal active blend layer thickness. As a model system, small concentrations of single wall carbon nanotubes are added to blends of poly(3-hexylthiophene): [6,6]-phenyl-C{sub 61}-butyric acid methyl ester in order to create networks of efficient hole conduction pathways in the device active layer without affecting the light absorption. The nanotube addition leads to a 22% increase in the optimal blend layer thickness from 90 nm to 110 nm, enhancing the short circuit current density and photovoltaic device efficiency by as much as {approx}10%. The associated incident-photon-to-current conversion efficiency for the given thickness also increases by {approx}10% uniformly across the device optical absorption spectrum, corroborating the enhanced charge carrier collection by nanostructured electrodes.

Nam, C.Y.; Wu, Q.; Su, D.; Chiu, C.-y; Tremblay, N.J.; Nuckolls, C,; Black, C.T.

2011-09-19T23:59:59.000Z

454

Low temperature phase transformations in 4-cyano-4'-pentylbiphenyl (5CB) filled by multiwalled carbon nanotubes  

E-Print Network (OSTI)

The effects of multiwalled carbon nanotubes (NTs) on low-temperature phase transformations in 5CB were studied by means of differential scanning calorimetry (DSC), low-temperature photoluminescence and measurements of electrical conductivity. The concentration of NTs was varied within 0-1% wt. The experimental data, obtained for pure 5CB by DSC and measurements of photoluminescence in the heating mode, evidenced the presence of two crystallization processes at T->229 K and T->262 K, which correspond to C1a->C1b, and C1b->C2 phase transformations. Increase of temperature T from 10 K to 229 K provoked the red shift of photoluminescence spectral band that was explained by flattening of 5CB molecule conformation. Moreover, the photoluminescence data allow to conclude that crystallisation at T=229 K results in conformation transition to non-planar 5CB structure characteristic to ideal crystal. The non-planar conformations were dominating in nematic phase, i.e., at T>297 K. Electrical conductivity data for NTs-5CB composites revealed supplementary anomaly inside the stable crystalline phase C2, identified earlier in the temperature range 229 K-296.8 K. It can reflect the influence of phase transformation of 5CB in interfacial layers on the transport of charge carriers between NTs.

N. Lebovka; V. Melnyk; Ye. Mamunya; G. Klishevich; A. Goncharuk; N. Pivovarova

2013-03-03T23:59:59.000Z

455

Processing, Characterization and Modeling Carbon Nanotube Modified Interfaces in Hybrid Polymer Matrix Composites  

E-Print Network (OSTI)

Multifunctional hybrid composites are proposed as novel solutions to meet the demands in various industrial applications ranging from aerospace to biomedicine. The combination of carbon fibers and/or fabric, metal foil and carbon nanotubes are utilized to develop such composites. This study focuses on processing of and fracture toughness characterization of the carbon fiber reinforced polymer matrix composites (PMC) and the CNT modified interface between PMC and a metal foil. The laminate fabrication process using H-VARTM, and the mode I interlaminar fracture toughness via double cantilever beam (DCB) tests at both room temperature and high temperature are conducted. The cross-sections and fracture surfaces of the panels are characterized using optical and scanning electron microscopes to verify the existence of CNTs at the interface before and after fracture tests. The experimental results reveal that CNT’s improve bonding at the hybrid interfaces. Computational models are developed to assist the interpretation of experimental results and further investigate damage modes. In this work, analytical solutions to compute the total strain energy release rate as well as mode I and mode II strain energy release rates of asymmetric configurations layups are utilized. Finite element models are developed in which the virtual crack closure technique is adopted to calculate strain energy release rates and investigate the degree and effect of mode-mixity. Results from analytical solutions agree well with each other and with results obtained from finite element models.

Truong, Hieu 1990-

2012-12-01T23:59:59.000Z

456

Electric field induced needle-pulsed arc discharge carbon nanotube production apparatus: Circuitry and mechanical design  

Science Conference Proceedings (OSTI)

A simple and low cost apparatus is reported to produce multiwall carbon nanotubes and carbon nano-onions by a low power short pulsed arc discharge reactor. The electric circuitry and the mechanical design details and a micro-filtering assembly are described. The pulsed-plasma is generated and applied between two graphite electrodes. The pulse width is 0.3 {mu}s. A strong dc electric field is established along side the electrodes. The repetitive discharges occur in less than 1 mm distance between a sharp tip graphite rod as anode, and a tubular graphite as cathode. A hydrocarbon vapor, as carbon source, is introduced through the graphite nozzle in the cathode assembly. The pressure of the chamber is controlled by a vacuum pump. A magnetic field, perpendicular to the plasma path, is provided. The results show that the synergetic use of a pulsed-current and a dc power supply enables us to synthesize carbon nanoparticles with short pulsed plasma. The simplicity and inexpensiveness of this plan is noticeable. Pulsed nature of plasma provides some extra degrees of freedom that make the production more controllable. Effects of some design parameters such as electric field, pulse frequency, and cathode shape are discussed. The products are examined using scanning probe microscopy techniques.

Kia, Kaveh Kazemi [Department of Electrical and Computer Engineering, Islamic Azad University of Bonab, Bonab (Iran, Islamic Republic of); Bonabi, Fahimeh [Department of Engineering, Islamic Azad University of Bonab, Bonab (Iran, Islamic Republic of)

2012-12-15T23:59:59.000Z

457

Pseudocapacitive Lithium-Ion Storage in Oriented Anatase TiO2 Nanotube Arrays  

SciTech Connect

We report on the synthesis and electrochemical properties of oriented anatase TiO{sub 2} nanotube (NT) arrays as electrodes for Li-ion batteries. The TiO{sub 2} NT electrodes displayed both pseudocapacitive Li{sup +} storage associated with the NT surface and the Li{sup +} storage within the bulk material. The relative contribution of the pseudocapacitive and bulk storages depends strongly on the scan rate. While the charges are stored primarily in the bulk at low scan rates (<< 1 mV/s), the surface storage dominates the total storage capacity at higher scan rates (>1 mV/s). The storage capacity of the NT electrodes as a function of charge/discharge rates showed no dependence on the NT film thickness, suggesting that the Li{sup +} insertion/extraction processes occur homogeneously across the entire length of NT arrays. These results indicated that the electron conduction along the NT walls and the ion conduction within the electrolyte do not cause significant hindering of the charge/discharge kinetics for NT electrode architectures. As a result of the surface pseudocapacitive storage, the reversible Li{sup +} storage capacities for TiO{sub 2} NT electrodes were higher than the theoretical storage capacity for bulk anatase TiO{sub 2} materials.

Zhu, K.; Wang, Q.; Kim, J. H.; Pesaran, A. A.; Frank, A. J.

2012-06-07T23:59:59.000Z

458

Water confined in nanotubes and between graphene sheets: A first principle study  

DOE Green Energy (OSTI)

Water confined at the nanoscale has been the focus of numerous experimental and theoretical investigations in recent years, y yet there is no consensus on such basic properties et as diffusion and the nature of hydrogen bonding (HB) under confinement. Unraveling these properties is important to understand fluid flow and transport at the nanoscale, and to shed light on the solvation of biomolecules. Here we report on a first principle, computational study focusing on water confined between prototypical non polar substrate, i.e. , single wall carbon nanotubes and graphene sheets, 1 to 2.5 nm apart. The results of our molecular dynamics simulations show the presence of a thin, interfacial liquid layer ({approx} 5 Angstroms) whose microscopic structure and thickness are independent of the distance between confining layers. The prop properties of the hydrogen bonded network are very similar to those of the bulk outside the interfacial region, even in the case of strong confinement , confinement. Our findings indicate that the perturbation induced by the presence of confining media is extremely local in liquid water, and we propose that many of the effects attributed to novel phases under confinement are determined by subtle electronic structure rearrangements occurring at the interface with the confining medium.

Cicero, G; Grossman, J C; Schwegler, E; Gygi, F; Galli, G

2008-10-17T23:59:59.000Z

459

Synthesis and characterization of carbon nanotubes using scanning probe based nano-lithographic techniques  

E-Print Network (OSTI)

A novel process which does not require the traditional Chemical Vapor Deposition (CVD) synthesis techniques and which works at temperatures lower than the conventional techniques was developed for synthesis of carbon nanotubes (CNT). The substrates used for this study involved MEMS (Micro Electrical Mechanical Systems) elements and passive elements. These were coated with Fullerene using Physical Vapor Deposition or through a solution in an organic solvent. Catalyst precursors were deposited on these Fullerene coated substrates using “wet processes”. These substrates were then heated using either the integrated microheaters or external heaters in an inert atmosphere to obtain CNT. Thus, in this process we tried to obviate the Chemical Vapor Deposition (CVD) process for synthesis of CNT (SWCNT and MWCNT). The synthesized CNT will be characterized using Scanning Electron Microscopy and Raman spectroscopy techniques. Also, conductivity measurements were carried out for the synthesized tubes using Dry (contact based) and Wet (electro-chemical) methods. This work also proves the concept for the feasibility for a portable hand held instrument for synthesis of CNT with tunable “on demand” chirality.

Gargate, Rohit Vasant

2008-12-01T23:59:59.000Z

460

Mechanism for high hydrogen storage capacity on metal-coated carbon nanotubes: A first principle analysis  

Science Conference Proceedings (OSTI)

The hydrogen adsorption and binding mechanism on metals (Ca, Sc, Ti and V) decorated single walled carbon nanotubes (SWCNTs) are investigated using first principle calculations. Our results show that those metals coated on SWCNTs can uptake over 8 wt% hydrogen molecules with binding energy range -0.2--0.6 eV, promising potential high density hydrogen storage material. The binding mechanism is originated from the electrostatic Coulomb attraction, which is induced by the electric field due to the charge transfer from metal 4s to 3d. Moreover, we found that the interaction between the H{sub 2}-H{sub 2} further lowers the binding energy. - Graphical abstract: Five hydrogen molecules bound to individual Ca decorated (8, 0) SWCNT : a potential hydrogen-storage material. Highlights: Black-Right-Pointing-Pointer Each transition metal atom can adsorb more than four hydrogen molecules. Black-Right-Pointing-Pointer The interation between metal and hydrogen molecule is electrostatic coulomb attraction. Black-Right-Pointing-Pointer The electric field is induced by the charge transfer from metal 4s to metal 3d. Black-Right-Pointing-Pointer The adsorbed hydrogen molecules which form supermolecule can further lower the binding energy.

Lu, Jinlian; Xiao, Hong [Department of Physics and Institute for nanophysics and Rare-earth Luminescence, Xiangtan University, Xiangtan, Hunan Province 411105 (China)] [Department of Physics and Institute for nanophysics and Rare-earth Luminescence, Xiangtan University, Xiangtan, Hunan Province 411105 (China); Cao, Juexian, E-mail: jxcao@xtu.edu.cn [Department of Physics and Institute for nanophysics and Rare-earth Luminescence, Xiangtan University, Xiangtan, Hunan Province 411105 (China)] [Department of Physics and Institute for nanophysics and Rare-earth Luminescence, Xiangtan University, Xiangtan, Hunan Province 411105 (China)

2012-12-15T23:59:59.000Z

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461

Final Technical Report CONDUCTIVE COATINGS FOR SOLAR CELLS USING CARBON NANOTUBES  

DOE Green Energy (OSTI)

US Department of Energy (DOE) awarded a grant for Eikos Inc. to investigate the feasibility of developing and utilizing Transparent Conducting Coatings (TCCs) based on carbon nanotubes (CNT) for solar cell applications. Conventional solar cells today employ metal oxide based TCCs with both Electrical Resistivity (R) and Optical Transparency (T), commonly referred to as optoelectronic (RT) performance significantly higher than with those possible with CNT based TCCs available today. Transparent metal oxide based coatings are also inherently brittle requiring high temperature in vacuum processing and are thus expensive to manufacture. One such material is indium tin oxide (ITO). Global demand for indium has recently increased rapidly while supply has diminished causing substantial spikes in raw material cost and availability. In contrast, the raw material, carbon, needed for CNT fabrication is abundantly available. Transparent Conducting Coatings based on CNTs can overcome not only cost and availability constraints while also offering the ability to be applied by existing, low cost process technologies under ambient conditions. Processes thus can readily be designed both for rigid and flexible PV technology platforms based on mature spray or dip coatings for silicon based solar cells and continuous roll to roll coating processes for polymer solar applications.

Paul J Glatkowski; Jorma Peltola; Christopher Weeks; Mike Trottier; David Britz

2007-09-30T23:59:59.000Z

462

Functionalization of multi-walled carbon nanotubes by epoxide ring-opening polymerization  

Science Conference Proceedings (OSTI)

In this study, covalent functionalization of carbon nanotubes (CNTs) was accomplished by surface-initiated epoxide ring-opening polymerization. FT-IR spectra showed that polyether and epoxide group covalently attached to the sidewalls of CNTs. TGA results indicated that the polyether was successfully grown from the CNT surface, with the final products having a polymer weight percentage of ca. 14-74 wt%. The O/C ratio of CNTs increased significantly from 5.1% to 29.8% after surface functionalization of CNTs. SEM and TEM images of functionalized CNTs exhibited that the tubes were enwrapped by polymer chains with thickness of several nanometers, forming core-shell structures with CNTs at the center. - Graphical abstract: Functionalized CNTs were enwrapped by polymer chains with thickness of several nanometers, forming core-shell structures with CNTs at the center. Highlights: Black-Right-Pointing-Pointer CNTs were functionalized by epoxide ring-opening polymerization. Black-Right-Pointing-Pointer Polyether and epoxide group covalently attached to the sidewalls of CNTs. Black-Right-Pointing-Pointer Functionalized CNTs have a polymer weight percentage of ca. 14-74 wt%. Black-Right-Pointing-Pointer Functionalized CNTs were enwrapped by polymer chains with thickness of several nanometers.

Jin Fanlong [School of Chemical and Materials Engineering, Jilin Institute of Chemical Technology, Jilin City 132022 (China); Rhee, Kyong Yop [Industrial Liaison Research Institute, Department of Mechanical Engineering, College of Engineering, Kyung Hee University, 446-701 Yongin (Korea, Republic of); Park, Soo-Jin, E-mail: sjpark@inha.ac.kr [Department of Chemistry, Inha University, Nam-gu, Incheon 402-751 (Korea, Republic of)

2011-12-15T23:59:59.000Z

463

A digital miniature x-ray tube with a high-density triode carbon nanotube field emitter  

Science Conference Proceedings (OSTI)

We have fabricated a digital miniature x-ray tube (6 mm in diameter and 32 mm in length) with a high-density triode carbon nanotube (CNT) field emitter for special x-ray applications. The triode CNT emitter was densely formed within a diameter of below 4 mm with the focusing-functional gate. The brazing process enables us to obtain and maintain a desired vacuum level for the reliable electron emission from the CNT emitters after the vacuum packaging. The miniature x-ray tube exhibited a stable and reliable operation over 250 h in a pulse mode at an anode voltage of above 25 kV.

Jeong, Jin-Woo; Kang, Jun-Tae; Choi, Sungyoul [Nano Electron-source Creative Research Center, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700 (Korea, Republic of)] [Nano Electron-source Creative Research Center, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700 (Korea, Republic of); Kim, Jae-Woo; Song, Yoon-Ho [Nano Electron-source Creative Research Center, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700 (Korea, Republic of) [Nano Electron-source Creative Research Center, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700 (Korea, Republic of); School of Advanced Device Engineering, University of Science and Technology, 217 Gajeong-ro, Yuseong-gu, Daejeon 305-350 (Korea, Republic of); Ahn, Seungjoon [Nano Electron-source Creative Research Center, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700 (Korea, Republic of) [Nano Electron-source Creative Research Center, Electronics and Telecommunications Research Institute, 218 Gajeong-ro, Yuseong-gu, Daejeon 305-700 (Korea, Republic of); Department of Information Display, Sun Moon University, Kalsan-ri, Tangjeong-myoon, Asan-si, Chungnam 336-708 (Korea, Republic of)

2013-01-14T23:59:59.000Z

464

Low Power, Red, Green and Blue Carbon Nanotube Enabled Vertical Organic Light Emitting Transistors for Active Matrix OLED Displays  

SciTech Connect

Organic semiconductors are potential alternatives to polycrystalline silicon as the semiconductor used in the backplane of active matrix organic light emitting diode displays. Demonstrated here is a light-emitting transistor with an organic channel, operating with low power dissipation at low voltage, and high aperture ratio, in three colors: red, green and blue. The single-wall carbon nanotube network source electrode is responsible for the high level of performance demonstrated. A major benefit enabled by this architecture is the integration of the drive transistor, storage capacitor and light emitter into a single device. Performance comparable to commercialized polycrystalline-silicon TFT driven OLEDs is demonstrated.

McCarthy, M. A. [University of Florida, Gainesville; Liu, B. [University of Florida, Gainesville; Donoghue, E. P. [University of Florida, Gainesville; Kravchenko, Ivan I [ORNL; Kim, D. Y. [University of Florida, Gainesville; So, Franky [University of Florida, Gainesville; Rinzler, A. G. [University of Florida, Gainesville

2011-01-01T23:59:59.000Z

465

Effects of Silicon and Carbon Composition on Carbon Nanotubes in Lithium-Ion Batteries Sadie Roberts, Georgia Institute of Technology Georgia Tech SURF 2011 Fellow  

E-Print Network (OSTI)

Effects of Silicon and Carbon Composition on Carbon Nanotubes in Lithium-Ion Batteries Sadie Graduate Mentor: Kara Evanoff Introduction Lithium-ion (Li-ion) batteries are attractive for many] Magasinki, A.; Dixon, P.; Hertzberg, B.; Kvit, A.; Ayala, J.; Yushin, G., "High-performance lithium-ion

Li, Mo

466

Influence of the pore size in multi-walled carbon nanotubes on the hydrogen storage behaviors  

SciTech Connect

Activated multi-walled carbon nanotubes (A-MWCNTs) were prepared using a chemical activation method to obtain well-developed pore structures for use as hydrogen storage materials. The microstructure and crystallinity of the A-MWCNTs were evaluated by X-ray diffraction and Fourier transform Raman spectroscopy. The textural properties of the A-MWCNTs were investigated by nitrogen gas sorption analysis at 77 K. The hydrogen storage capacity of the A-MWCNTs was evaluated at 77 K and 1 bar. The results showed that the specific surface area of the MWCNTs increased from 327 to 495 m{sup 2}/g as the activation temperature was increased. The highest hydrogen storage capacity was observed in the A-MWCNTs sample activated at 900 Degree-Sign C (0.54 wt%). This was attributed to it having the narrowest microporosity, which is a factor closely related to the hydrogen storage capacity. This shows that the hydrogen storage behaviors depend on the pore volume. Although a high pore volume is desirable for hydrogen storage, it is also severely affected if the pore size in the A-MWCNTs for the hydrogen molecules is suitable for creating the activation process. Highlights: Black-Right-Pointing-Pointer The AT-800 and AT-900 samples were prepared by a chemical activation method at activation temperature of 800 and 900 Degree-Sign C, respectively. Black-Right-Pointing-Pointer The AT-900 sample has the narrowest peak in comparison with the AT-800 sample, resulting from the overlap of the two peaks (Peak I and Peak II). Black-Right-Pointing-Pointer This overlapping effect is due to the newly created micropores or shrinkages of pores in Peak II. So, these determining characteristics are essential for designing materials that are suitable for molecular hydrogen storage.

Lee, Seul-Yi [Department of Chemistry, Inha University, 253, Nam-gu, Incheon 402-751 (Korea, Republic of)] [Department of Chemistry, Inha University, 253, Nam-gu, Incheon 402-751 (Korea, Republic of); Park, Soo-Jin, E-mail: sjpark@inha.ac.kr [Department of Chemistry, Inha University, 253, Nam-gu, Incheon 402-751 (Korea, Republic of)] [Department of Chemistry, Inha University, 253, Nam-gu, Incheon 402-751 (Korea, Republic of)

2012-10-15T23:59:59.000Z

467

Surface-Initiated Titanium-Mediated Coordination Polymerization from Catalyst-Functionalized Single and Multiwalled Carbon Nanotubes  

Science Conference Proceedings (OSTI)

Single (SWNTs) and multiwalled (MWNTs) carbon nanotubes were functionalized with a titanium alkoxide catalyst through a Diels-Alder cycloaddition reaction. The catalyst-functionalized carbon nanotubes (CNTs) were used for the surface initiated titanium-mediated coordination polymerizations of L-lactide (L-LA), -caprolactone (-CL) and n-hexyl isocyanate (HIC) employing the grafting from technique. 1H NMR, IR and Raman spectra showed that the precursor catalyst was successfully synthesized and covalently attached on the CNTs surface. Thermogravimetric analysis (TGA) revealed that the grafted poly(L-lactide) (PLLA) content could be controlled with time. The final polymer-grafted CNTs were readily dissolved in organic solvents as compared to the insoluble pristine and catalyst-functionalized CNTs. The presence of thick layers of polymers around the CNTs was observed through transmission electron microscopy (TEM). Differential scanning calorimetry (DSC) proved that the glass transition (Tg) and melting (Tm) temperatures of the PLLA are affected by the presence of the CNTs, while PLLA R-helix conformation remains intact, as revealed by the circular dichroism (CD) spectra.

Priftis, Dimitrios [ORNL; Petzetakis, Nikolaos [University of Athens, Athens, Greece; Sakellariou, Georgios [ORNL; Pitsikalis, Marinos [ORNL; Baskaran, Durairaj [University of Tennessee, Knoxville (UTK); Mays, Jimmy [ORNL; Hadjichristidis, Nikos [University of Athens, Athens, Greece

2009-01-01T23:59:59.000Z

468

Improvement in the Mechanical Properties of B-Staged Carbon Nanotube/Epoxy Based Thin Film Systems  

E-Print Network (OSTI)

Polymeric systems have been the subject of tremendous interest to the aerospace industry due to their high strength per weight ratio but have not seen the use projected due to their poor compression after impact strength, fracture toughness, and electrical conductivity. This work has focused on the integration of single walled carbon nanotubes (SWCNTs) into polymeric systems to serve as interleaves to improve the mechanical properties of carbon fiber panels. Pristine, oxidized, and functionalized carbon nanotubes were produced and cast into B-staged (50% cured) thin film epoxy resin systems. Mechanical characterizations were carried out on bulk samples and showed that the introduction of well dispersed SWCNTs functionalized with sulfanilamide improved the Young’s modulus of the neat epoxy by 16%, the tensile strength by 47%, the elongation at break by 157%, and the fracture toughness, as determined by KIC, by 10%. Nylon was introduced into the system as a toughening agent at 10 wt% and showed an 8% increase in the Young’s modulus, a 29% increase in iv tensile strength, a 183% increase in elongation at break, and a 44% increase in fracture toughness. These composite films were successfully transferred into a carbon fiber interleave using Vacuum Assisted Resin Transfer Molding (VARTM).

White, Kevin

2011-01-11T23:59:59.000Z

469

A characterization of the interfacial and interlaminar properties of carbon nanotube modified carbon fiber/epoxy composites  

E-Print Network (OSTI)

The mechanical characterization of the interfacial shear strength (IFSS) of carbon nanotube (CNT) coated carbon fibers and the interlaminar fracture toughness of woven fabric carbon fiber/epoxy composites toughened with CNT/epoxy interleave films is presented. The deposition of multiwalled carbon nanotubes (MWCNT) onto the surface of carbon fibers through thermal chemical vapor deposition (CVD) was used in an effort to produce a graded, multifunctional interphase region used to improve the interfacial strength between the matrix and the reinforcing fiber. Characterization of the IFSS was performed using the single-fiber fragmentation test. It is shown that the application of a MWCNT coating improves the interfacial shear strength between the coated fiber and matrix when compared with uncoated fibers. The effect of CNT/epoxy thin interleave films on the Mode I interlaminar fracture toughness of woven fabric carbon/epoxy composites is examined using the double-cantilever beam (DCB) test. Initiation fracture toughness, represented by critical strain energy release rate (GIC), is shown to improve over standard un-toughened composites using amine-functionalized CNT/epoxy thin films. Propagation fracture toughness is shown to remain unaffected using amine-functionalized CNT/epoxy thin films with respect to standard un-toughened composites.

Sager, Ryan James

2008-05-01T23:59:59.000Z

470

CONTROLLED GROWTH OF CARBON NANOTUBES ON CONDUCTIVE METAL SUBSTRATES FOR ENERGY STORAGE APPLICATIONS  

Science Conference Proceedings (OSTI)

The impressive mechanical and electronic properties of carbon nanotubes (CNTs) make them ideally suited for use in a variety of nanostructured devices, especially in the realm of energy production and storage. In particular, vertically-aligned CNT “forests” have been the focus of increasing investigation for use in supercapacitor electrodes and as hydrogen adsorption substrates. Vertically-aligned CNT growth was attempted on metal substrates by waterassisted chemical vapor deposition (CVD). CNT growth was catalyzed by iron-molybdenum (FeMo) nanoparticle catalysts synthesized by a colloidal method, which were then spin-coated onto Inconel® foils. The substrates were loaded into a custom-built CVD apparatus, where CNT growth was initiated by heating the substrates to 750 °C under the fl ow of He, H2, C2H4 and a controlled amount of water vapor. The resultant CNTs were characterized by a variety of methods including Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM), and the growth parameters were varied in an attempt to optimize the purity and growth yield of the CNTs. The surface area and hydrogen adsorption characteristics of the CNTs were quantifi ed by the Brunauer- Emmett-Teller (BET) and Sieverts methods, and their capacitance was measured via cyclic voltammetry. While vertically-aligned CNT growth could not be verifi ed, TEM and SEM analysis indicated that CNT growth was still obtained, resulting in multiwalled CNTs of a wide range in diameter along with some amorphous carbon impurities. These microscopy fi ndings were reinforced by Raman spectroscopy, which resulted in a G/D ratio ranging from 1.5 to 3 across different samples, suggestive of multiwalled CNTs. Changes in gas fl ow rates and water concentration during CNT growth were not found to have a discernable effect on the purity of the CNTs. The specifi c capacitance of a CNT/FeMo/Inconel® electrode was found to be 3.2 F/g, and the BET surface area of a characteristic CNT sample was measured to be 232 m2/g with a cryogenic (77K) hydrogen storage of 0.85 wt%. This level of hydrogen adsorption is slightly higher than that predicted by the Chahine rule, indicating that these CNTs may bind hydrogen more strongly than other carbonaceous materials. More work is needed to confi rm and determine the reason for increased hydrogen adsorption in these CNTs, and to test them for use as catalyst support networks. This study demonstrates the feasibility of producing CNTs for energy storage applications using water-assisted CVD.

Brown, P.; Engtrakul, C.

2009-01-01T23:59:59.000Z

471

Electrospinning of Cellulose and Carbon Nanotube-Cellulose Fibers for Smart Applications  

E-Print Network (OSTI)

Cellulose is one of the Earth’s most abundant natural polymers and is used as a raw material in various applications. Recently, cellulose based electro-active paper (EAPap) has been investigated for its potential as a smart material. The electrospinning method of fiber production is not a new way of fabrication; however, it has attracted a great deal of attention as a means of producing non-woven membranes of nanofibers due to its simple methodology and the advent of nano applications. Electrospinning occurs when the electrical force on a polymer droplet overcomes its surface tension, and a charged jet is ejected. As the liquid jet is continuously elongated and the solvent is evaporated, the fibers of sub-micron size or nano size are formed, depending on the conditions. In a previous study, a cellulose mat was electro-spun and tested for piezoelectric characteristics. This aligned, electrospun cellulose mat showed a possibility as a promising smart material. Additionally, carbon nanotubes have been considered for the versatile nano-applications due to their superior material properties such as low density and high aspect ratio. Parametric studies were conducted to find optimum conditions for electrospinning. Various ways of reducing surface tension of solutions were investigated including radiative and convective heating of the solution. Pre-examination of solution is very important in consistent, uniform fiber formation. In this study, cellulose and CNT-cellulose composite fibers were prepared via electrospinning. The optimal experimental conditions for fiber generation were found so that the mechanical strength of both the composite and the pure cellulose fibers could be compared in future tests. Eventually, this fiber will be interwoven into the CNT-cellulose mat and be used as an electro-active paper sensor and actuator. The CNT-cellulose electrospun mat will be widely applicable to the fields of sensors, filters and reinforcements in composites because of its intrinsic properties of porosity, light weight, flexibility, and large surface area. To be used in the aforementioned applications, piezoelectric properties of this composite will also be tested in the next step.

Pankonien, Alexander

2008-08-19T23:59:59.000Z

472

Pt-Co Bimetallic Catalyst Supported on Single-Walled Carbon Nanotubes: Effect of Alloy Formation and Oxygen Containing Groups †  

E-Print Network (OSTI)

Pt monometallic and Pt-Co bimetallic catalysts have been prepared on single-walled carbon nanotubes (SWNT) with and without HNO3 treatment. The HNO3 treatment introduced oxygen containing groups (OCGs), which affect both the structure and activity of the catalyst. The introduction of OCGs does not affect the structure of Pt monometallic catalysts but increased the dispersion in the bimetallic catalysts. The aqueous phase reforming (APR) activity of the bimetallic catalysts is also affected by the OCGs, because the local concentration of the reactant around the SWNT support with OCGs is less than the case without OCGs. The two effects act on activity in opposing directions so the bimetallic catalysts on the two supports give similar APR yields, but this discovery gives us direction and a basis for the future design and improvement of SWNT supported catalysts. 1.

Xiaoming Wang; Nan Li; Lisa D. Pfefferle; Gary L. Haller

2010-01-01T23:59:59.000Z

473

Mode-locking of solid-state lasers by single-walled carbon-nanotube based saturable absorbers  

Science Conference Proceedings (OSTI)

Universal use of single-walled carbon-nanotube based saturable absorber devices for mode-locking of bulk solid-state lasers between 0.8 and 2 {mu}m is discussed. The advantages in comparison to semiconductor saturable absorbers are emphasised. We briefly describe the manufacturing process and the essential optical properties, and review experimental results obtained with various types of femtosecond and picosecond solid-state lasers in the steady-state regime. We also demonstrate that a single hybrid saturable absorber used in transmission can be used to mode-lock four different types of lasers operating between 1 and 2 {mu}m. (control of laser radiation parameters)

Rotermund, F; Cho, W B; Choi, S Y; Baek, I H; Yim, J H; Lee, S; Schmidt, A; Steinmeyer, G; Griebner, U; Yeom, D I; Kim, K; Petrov, V

2012-08-31T23:59:59.000Z

474

Growth of single-crystal {alpha}-MnO{sub 2} nanorods on multi-walled carbon nanotubes  

Science Conference Proceedings (OSTI)

Single-crystal {alpha}-MnO{sub 2} nanorods were grown on multi-walled carbon nanotubes (MWNTs) in H{sub 2}SO{sub 4} aqueous solution. The morphology and microstructure of the composites were examined by transmission electron microscopy, high-resolution transmission electron microscopy (HRTEM), X-ray diffractometry and energy dispersive spectroscopy (EDS). The results show that {alpha}-MnO{sub 2} single-crystal nanorods with a mean diameter of 15 nm were densely grown on the surface of MWNTs. Those MWNTs/MnO{sub 2} composites were used as an electrode material for supercapacitors, and it was found that the supercapacitor performance using MWNTs/MnO{sub 2} composites was improved largely compared to that using pure MWNTs and {alpha}-MnO{sub 2} nanorod mechanically mixed with MWNTs.

Chen Yong [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Key Laboratory of Tropic Biological Resources, MOE, Hainan University, 58 Renmin Road, Haikou 570228 (China); Liu Chenguang; Liu Chang [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Lu Gaoqing [ARC Centre for Functional Nanomaterials, Australian Institute of Bioengineering and Nanotechnology, University of Queensland, QLD 4072 (Australia); Cheng Huiming [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)], E-mail: cheng@imr.ac.cn

2007-11-06T23:59:59.000Z

475

Application of Single Wall Carbon Nanotubes as Transparent Electrodes in Cu(In,Ga)Se2-Based Solar Cells: Preprint  

DOE Green Energy (OSTI)

We present a new thin-film solar cell structure in which the traditional transparent conductive oxide electrode (ZnO) is replaced by a transparent conductive coating consisting of a network of bundled single-wall carbon nanotubes. Optical transmission properties of these coatings are presented in relation to their electrical properties (sheet resistance), along with preliminary solar cell results from devices made using CuIn1-xGaxSe2 thin-film absorber materials. Achieving an energy conversion efficiency of >12% and a quantum efficiency of {approx}80% demonstrate the feasibility of the concept. A discussion of the device structures will be presented considering the physical properties of the new electrodes comparing current-voltage results from the new solar cell structure and those from standard ZnO/CdS/Cu(In,Ga)Se2/Mo solar cells.

Contreras, M.; Barnes, T.; van de Lagemaat, J.; Rumbles, G.; Coutts, T. J.; Weeks, C.; Glatkowski, P.; Levitsky, I.; Peltola, J.

2006-05-01T23:59:59.000Z

476

Dynamical Core-Hole Screening in the X-Ray Absorption Spectra of Hydrogenated Carbon Nanotubes And Graphene  

Science Conference Proceedings (OSTI)

We have calculated the electronic structure and the x-ray absorption (XA) spectrum of a hydrogenated single graphite plane, in order to simulate recent experimental results on hydrogenated single wall carbon nanotubes (SWCNT) as well as hydrogenated graphene. We find that the presence of H induces a substantial component of sp{sup 3} bonding and as a result the {pi} and {pi}* components to the electronic structure vanish. We have calculated a theoretical x-ray absorption spectrum using a multiband version of the Mahan-Nozieres-De Dominicis theory. By making a fitting of the XA signal of C atoms that have H attached to them and C atoms without H in the vicinity we obtain a good representation of the experimental data and we can draw the conclusion that in the experiments [A. Nikitin et al., Phys. Rev. Lett. 95, 225507 (2005)] some 35-50 % H have been absorbed in the SWCNT.

Wessely, O.; /Uppsala U. /Imperial Coll., London; Katsnelson, M.I.; /Nijmegen U.; Nilsson, A.; /SLAC, SSRL /Stockholm U.; Nikitin, A.; Ogasawara, H.; /SLAC, SSRL; Odelius, M.; /Stockholm U.; Sanyal, B.; Eriksson, O.; /Uppsala U.

2009-04-30T23:59:59.000Z

477

Electron-beam induced electric-hydraulic expansion in a silica-shelled gallium microball-nanotube structure  

Science Conference Proceedings (OSTI)

Heteroshape-heteroscale structure of silica-shelled Ga microball-nanotube was fabricated. Under in situ electron-beam irradiation, an abnormally large and fast expansion of Ga was observed. Failed by a sole routine heating effect of electron-beam, the expansion was explained by an electric-hydraulic expansion effect taking into account a huge inner pressure induced by the repelling Coulomb force of positively charged Ga ions on the Ga microball surface. The ions were accumulated due to knocking-out of Ga electrons under irradiation and shielding effect of a silica shell which prevents the charge balance restoration. A circuit model is proposed to calculate the accumulation of Ga ions.

Gao, Y. H.; Sun, M.; Su, J. [Wuhan National Laboratory for Optoelectronics (WNLO), School of Physics, College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology (HUST), LuoyuRoad 1037, Wuhan 430074 (China); Zhi, C. Y.; Golberg, D.; Bando, Y. [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Duan, X. F. [Institute of Physics, Beijing National Laboratory of Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2011-08-22T23:59:59.000Z

478

Thermal Performance of a Novel Heat Transfer Fluid Containing Multiwalled Carbon Nanotubes and Microencapsulated Phase Change Materials  

E-Print Network (OSTI)

The present research work aims to develop a new heat transfer fluid by combining multiwalled carbon nanotubes (MWCNT) and microencapsulated phase change materials (MPCMs). Stable nanofluids have been prepared using different sizes of multiwalled carbon nanotubes and their properties like thermal conductivity and viscosity have been measured. Microencapsulated phase change material slurries containing microcapsules of octadecane have been purchased from Thies Technology Inc. Tests have been conducted to determine the durability and viscosity of the MPCM slurries. Heat transfer experiments have been conducted to determine the heat transfer coefficients and pressure drop of the MWCNT nanofluids and MPCM slurries under turbulent flow and constant heat flux conditions. The MPCM slurry and the MWCNT nanofluid have been combined to form a new heat transfer fluid. Heat transfer tests have been conducted to determine the heat transfer coefficient and the pressure drop of the new fluid under turbulent flow and constant heat flux conditions. The potential use of this fluid in convective heat transfer applications has also been discussed. The heat transfer results of the MPCM slurry containing octadecane microcapsules was in good agreement with the published literature. The thermal conductivity enhancement obtained for MWCNTs with diameter (60-100 nm) and length (0.5-40?m) was 8.11%. The maximum percentage enhancement (compared to water) obtained in the heat transfer coefficient of the MWCNT nanofluid was in the range of 20-25%. The blend of MPCMs and MWCNTs was highly viscous and displayed a shear thinning behavior. Due to its high viscosity, the flow became laminar and the heat transfer performance was lowered. It was interesting to observe that the value of the maximum local heat transfer coefficient achieved in the case of the blend (laminar flow), was comparable to that obtained in the case of the MPCM slurry (turbulent flow). The pressure drop of the blend was lower than that of the MWCNT nanofluid.

Tumuluri, Kalpana

2010-05-01T23:59:59.000Z

479

Effects of Carbon Nanotube Coating on Bubble Departure Diameter and Frequency in Pool Boiling on a Flat, Horizontal Heater  

E-Print Network (OSTI)

The effects of a carbon nanotube (CNT) coating on bubble departure diameter and frequency in pool boiling experiments was investigated and compared to those on a bare silicon wafer. The pool boiling experiments were performed at liquid subcooling of 10 degrees Celsius and 20 degrees Celsius using PF-5060 as the test fluid and at atmospheric pressure. High-speed digital image acquisition techniques were used to perform hydrodynamic measurements. Boiling curves obtained from the experiments showed that the CNT coating enhanced critical heat flux (CHF) by 63% at 10 degrees Celsius subcooling. The CHF condition was not measured for the CNT sample at 20 degrees Celsius subcooling. Boiling incipience superheat for the CNT-coated surface is shown to be much lower than predicted by Hsu's hypothesis. It is proposed that bubble nucleation occurs within irregularities at the surface of the CNT coating. The irregularities could provide larger cavities than are available between individual nanotubes of the CNT coating. Measurements from high-speed imaging showed that the average bubble departing from the CNT coating in the nucleate boiling regime (excluding the much larger bubbles observed near CHF) was about 75% smaller (0.26 mm versus 1.01 mm)and had a departure frequency that was about 70% higher (50.46 Hz versus 30.10 Hz). The reduction in departure diameter is explained as a change in the configuration of the contact line, although further study is required. The increase in frequency is a consequence of the smaller bubbles, which require less time to grow. It is suggested that nucleation site density for the CNT coating must drastically increase to compensate for the smaller departure diameters if the rate of vapor creation is similar to or greater than that of a bare silicon surface.

Glenn, Stephen T.

2009-08-01T23:59:59.000Z

480

Anomalous selective reflection in cholesteryl oleyl carbonate - nematic 5CB mixtures and effects of their doping by single-walled carbon nanotubes  

E-Print Network (OSTI)

Liquid crystalline (LC) mixtures of cholesteryl oleyl carbonate (COC) and 4-pentyl-4'-cyanobiphenyl (5CB), as well as dispersions of single-walled carbon nanotubes (NTs) in these mixtures, were studied by means of selective reflection measurements, differential scanning calorimetry (DSC) and optical microscopy. The relative mass of COC in a mixture X was varied between 0.4 and 1.0, the temperature range of measurements was between 284 K and 314 K, and concentration of NTs was fixed at 0.1 %. Two important anomalies were noted: (1) the cholesteric to smectic-A transition temperature increased on dilution of COC by non-smectogenic 5CB in the concentration range 0.8carbon nanotubes.

N. I. Lebovka; L. N. Lisetski; M. I. Nesterenko; V. D. Panikarskaya; N. A. Kasian; S. S. Minenko; M. S. Soskin

2013-03-03T23:59:59.000Z

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481

Photoelectrochemical water splitting and simultaneous photoelectrocatalytic degradation of organic pollutant on highly smooth and ordered TiO{sub 2} nanotube arrays  

SciTech Connect

The photoelectrochemical water splitting and simultaneous photoelectrocatalytic degradation of organic pollutant were achieved on TiO{sub 2} nanotube electrodes with double purposes of environmental protection and renewable energy production under illumination of simulated solar light. The TiO{sub 2} nanotube arrays (TiO{sub 2} NTs) were fabricated by a two-step anodization method. The TiO{sub 2} NTs prepared in two-step anodization process (2-step TiO{sub 2} NTs) showed much better surface smoothness and tube orderliness than TiO{sub 2} NTs prepared in one-step anodization process (1-step TiO{sub 2} NTs). In the photoelectrochemical water splitting and simultaneous photoelectrocatalytic decomposition process, the 2-step TiO{sub 2} NTs electrode showed both highest photo-conversion efficiency of 1.25% and effective photodecomposition efficiency with existing of methylene blue (MB) as sacrificial agent and as pollutant target. Those results implied that the highly ordered nanostructures provided direct pathway and uniform electric field distribution for effective charges transfer, as well as superior capabilities of light harvesting. - Graphical Abstract: The photoelectrochemical water splitting for hydrogen generation and simultaneous photoelectrocatalytic degradation of organic pollutant (methylene blue) were achieved on TiO{sub 2} nanotube electrodes with double purposes of environmental protection and renewable energy production under illumination of simulated solar light. Highlights: Black-Right-Pointing-Pointer TiO{sub 2} nanotube arrays were fabricated by a two-step anodization method. Black-Right-Pointing-Pointer Hydrogen generation and organic pollutant degradation were achieved on TiO{sub 2} NTs. Black-Right-Pointing-Pointer Highest photoconversion efficiency of 1.25% was achieved. Black-Right-Pointing-Pointer Increasing orderliness will increase photocatalytic activity of TiO{sub 2} NTs.

Wu Hongjun [College of Chemistry and Chemical Engineering, Northeast Petroleum University, Daqing 163318 (China); Institute of Basic Energy Science and Technology, George Washington University, VA 20147 (United States); Zhang Zhonghai, E-mail: zhonghaizhangwill@gmail.com [Institute of Basic Energy Science and Technology, George Washington University, VA 20147 (United States); Graduate School of Science and Engineering for Research, University of Toyama, 3190 Gofuku, Toyama 930-8555 (Japan)

2011-12-15T23:59:59.000Z

482

High resolution stationary digital breast tomosynthesis using distributed carbon nanotube x-ray source array  

Science Conference Proceedings (OSTI)

Purpose: The purpose of this study is to investigate the feasibility of increasing the system spatial resolution and scanning speed of Hologic Selenia Dimensions digital breast tomosynthesis (DBT) scanner by replacing the rotating mammography x-ray tube with a specially designed carbon nanotube (CNT) x-ray source array, which generates all the projection images needed for tomosynthesis reconstruction by electronically activating individual x-ray sources without any mechanical motion. The stationary digital breast tomosynthesis (s-DBT) design aims to (i) increase the system spatial resolution by eliminating image blurring due to x-ray tube motion and (ii) reduce the scanning time. Low spatial resolution and long scanning time are the two main technical limitations of current DBT technology. Methods: A CNT x-ray source array was designed and evaluated against a set of targeted system performance parameters. Simulations were performed to determine the maximum anode heat load at the desired focal spot size and to design the electron focusing optics. Field emission current from CNT cathode was measured for an extended period of time to determine the stable life time of CNT cathode for an expected clinical operation scenario. The source array was manufactured, tested, and integrated with a Selenia scanner. An electronic control unit was developed to interface the source array with the detection system and to scan and regulate x-ray beams. The performance of the s-DBT system was evaluated using physical phantoms. Results: The spatially distributed CNT x-ray source array comprised 31 individually addressable x-ray sources covering a 30 angular span with 1 pitch and an isotropic focal spot size of 0.6 mm at full width at half-maximum. Stable operation at 28 kV(peak) anode voltage and 38 mA tube current was demonstrated with extended lifetime and good source-to-source consistency. For the standard imaging protocol of 15 views over 14, 100 mAs dose, and 2 x 2 detector binning, the projection resolution along the scanning direction increased from 4.0 cycles/mm [at 10% modulation-transfer-function (MTF)] in DBT to 5.1 cycles/mm in s-DBT at magnification factor of 1.08. The improvement is more pronounced for faster scanning speeds, wider angular coverage, and smaller detector pixel sizes. The scanning speed depends on the detector, the number of views, and the imaging dose. With 240 ms detector readout time, the s-DBT system scanning time is 6.3 s for a 15-view, 100 mAs scan regardless of the angular coverage. The scanning speed can be reduced to less than 4 s when detectors become faster. Initial phantom studies showed good quality reconstructed images. Conclusions: A prototype s-DBT scanner has been developed and evaluated by retrofitting the Selenia rotating gantry DBT scanner with a spatially distributed CNT x-ray source array. Preliminary results show that it improves system spatial resolution substantially by eliminating image blur due to x-ray focal spot motion. The scanner speed of s-DBT system is independent of angular coverage and can be increased with faster detector without image degration. The accelerated lifetime measurement demonstrated the long term stability of CNT x-ray source array with typical clinical operation lifetime over 3 years.

Qian Xin; Tucker, Andrew; Gidcumb, Emily; Shan Jing; Yang Guang; Calderon-Colon, Xiomara; Sultana, Shabana; Lu Jianping; Zhou, Otto; Spronk, Derrek; Sprenger, Frank; Zhang Yiheng; Kennedy, Don; Farbizio, Tom; Jing Zhenxue [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Curriculum in Applied Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Curriculum in Applied Sciences and Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States) and Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States) Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States) and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 (United States); XinRay Systems, Inc., Research Triangle Park, North Carolina 27709 (United States); Hologic, Inc., Bedford, Massachusetts 01730 (United States)

2012-04-15T23:59:59.000Z

483

Aspect Ratio Effect of Functionalized/Non-Functionalized Multiwalled Carbon Nanotubes on the Mechanical Properties of Cementitious Materials  

E-Print Network (OSTI)

The focus of this research was to investigate the use of functionalized/non-functionalized multi walled carbon nanotubes (MWCNTs) as reinforcements for the Portland cement paste. The unique geometrical characteristics of the carbon nanotubes (CNTs), as well as its unique mechanical properties such as high strength, ductility and stiffness, were the vital motivation for this study. In this research, we combined this unique material (CNTs) with concrete which is the most used man-made material. When compared to other composite materials, a limited amount of research has been conducted on the CNTs/cement composites. In order to investigate how the aspect ratio of functionalized/non-functionalized MWCNTs affects the mechanical properties of cementitious composites, ten different mixes of the MWCNTs/cement composites were prepared and tested. The different batches had a fixed water/cement ratio of 0.4, and variations of MWCNTs length, concentration and surface treatment. The cement nanocomposites were cast in small-scale specimens (beams) for the three-point flexural testing. Four major mechanical properties were evaluated at ages of 7, 14, and 28 days from the casting day: the maximum flexural strength, ultimate strain capacity (ductility), modulus of elasticity, and modulus of toughness. The results for the different nanocomposite batches were compared with the plain cement (reference) batch. The mechanical testing results showed that at 28 days almost all of the MWCNTs composites increased the flexural strength of the cement nanocomposites. At 28 days, the long MWCNTs increased the flexural strength more than the short MWCNTs. In general, the ultimate strain (ductility) of the short MWCNTs nanocomposites was higher than the ultimate strain of the long MWCNTs nanocomposites. The flexural strength of short 0.2 percent MWNT and long 0.04 percent MWNT (OH) increased by 269 percent and 83 percent, respectively, compared to the plain cement sample at 28 days. The highest ductility at 28 days for the short 0.1 percent MWNT and the short 0.2 percent MWNT was 86 percent and 81 percent, respectively. Clear evidence was obtained from the SEM images for micro-crack bridging; many of the MWCNTs were stretching across the micro-cracks. In conclusion, CNTs as nano reinforcements, can effectively improve certain mechanical properties of the cement paste composites.

Ashour, Ahmad

2011-08-01T23:59:59.000Z

484

Effect of Surface Oxygen Containing Groups on the Catalytic Activity of Multi-walled Carbon Nanotube Supported Pt Catalyst  

Science Conference Proceedings (OSTI)

Multi-walled carbon nanotubes (MWNT) supported platinum catalysts were employed to study the support functionalization on their catalytic performances. The MWNT were subjected to HNO{sub 3} functionalization, in which oxygen-containing-groups (OCGs) were introduced to improve Pt dispersion. The MWNT supports were characterized by nitrogen physisorption and NEXAFS, and the Pt supported on differently functionalized MWNT characterized by X-ray absorption, TEM and both hydrogen and CO chemisorption. Compared to the as received MWNT supports, Pt dispersion is improved on the HNO3 treated MWNT supports, but the turnover frequency (TOF) of aqueous phase reforming decreases by half. The TOF can be recovered by removing the OCGs via high temperature annealing. To further investigate the OCGs effect, different probe reactions, including both steam reforming and liquid phase reforming of hydrocarbon oxygenates and dehydrogenation of alkanes in the liquid and gas phases, have been performed on the MWNT supported catalysts with different OCGs. A comparison of these reaction results suggests that OCGs are only detrimental to reactions in a binary mixture with two components of different hydrophilicity due to their competitive adsorption on the catalyst supports.

X Wang; N Li; J Webb; L Pfefferle; G Haller

2011-12-31T23:59:59.000Z

485

Electrodeposited Manganese Oxides on Three-Dimensional Carbon Nanotube Substrate: Supercapacitive Behaviour in Aqueous and Organic Electrolytes  

Science Conference Proceedings (OSTI)

Thin amorphous manganese oxide layers with a thickness of 3-5nm are electrodeposited on a carbon nanotube (CNT) film substrate that has a three-dimensional nanoporous structure (denoted asMnO2/CNT electrode). For the purpose of comparison, manganese oxide films are also electrodeposited on a flat Pt-coated Si wafer substrate (denoted as MnO2 film electrode). The pseudocapacitive properties of the MnO2 film and MnO2/CNT electrodes are examined in both aqueous electrolyte (1.0M KCl) and nonaqueousorganic electrolyte (1.0M LiClO4 in propylene carbonate). While both types of electrode showpseudocapacitive behaviour in the aqueous electrolyte, only the MnO2/CNT electrode does so in the organic electrolyte, due to its high oxide/electrolyte interfacial area and improved electron conduction through the CNT substrate. Compared with the MnO2 film electrode, the MnO2/CNT electrode shows a much higher specific capacitance and better high-rate capability, regardless of the electrolyte used.Use of the organic electrolyte results in a ?6 times higher specific energy compared with that obtained with the aqueous electrolyte, while maintaining a similar specific power. The construction of a threedimensional nanoporous network structure consisting of a thin oxide layer on a CNT film substrate at the nm scale and the use of an organic electrolyte are promising approaches to improving the specific energyof supercapacitors.

Nam,K.W.; Yang,X.

2009-03-01T23:59:59.000Z

486

Electronic transport in oligo-para-phenylene junctions attached to carbon nanotube electrodes: Transition-voltage spectroscopy and chirality  

Science Conference Proceedings (OSTI)

We have investigated, by means of a nonequilibrium Green's function method coupled to density functional theory, the electronic transport properties of molecular junctions composed of oligo-para-phenylene (with two, three, four, and five phenyl rings) covalently bridging the gap between metallic carbon nanotubes electrodes. We have found that the current is strongly correlated to a purely geometrical chiral parameter, both on-resonance and off-resonance. The Fowler-Nordheim plot exhibits minima, V{sub min}, that occur whenever the tail of a resonant transmission peak enters in the bias window. This result corroborates the scenario in which the coherent transport model gives the correct interpretation to transition voltage spectroscopy (TVS). We have shown that V{sub min} corresponds to voltages where a negative differential resistance (NDR) occurs. The finding that V{sub min} corresponds to voltages that exhibit NDR, which can be explained only in single-molecule junctions within the coherent transport model, further confirms the applicability of such models to adequately interpret TVS. The fact that the electrodes are organic is at the origin of differences in the behavior of V{sub min} if compared to the case of molecular junctions with nonorganic contacts treated so far.

Brito Silva, C. A. Jr. [Pos-Graduacao em Engenharia Eletrica, Universidade Federal do Para, 66075-900, Belem, PA (Brazil); Faculdade de Ciencias Naturais, Universidade Federal do Para, 68800-000, Breves, PA (Brazil); Silva, S. J. S. da; Leal, J. F. P. [Pos-Graduacao em Fisica, Universidade Federal do Para, 66075-110, Belem, PA (Brazil); Pinheiro, F. A. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, 21941-972, Rio de Janeiro, RJ (Brazil); Del Nero, J. [Departamento de Fisica, Universidade Federal do Para, 66075-110, Belem, PA (Brazil); Departement de Physique, Ecole Normale Superieure, F-75231, Paris (France)

2011-06-15T23:59:59.000Z

487

Synthesis and characterization of sulfonated single-walled carbon nanotubes and their performance as solid acid catalyst  

SciTech Connect

Single-walled carbon nanotubes (SWCNTs) were treated with sulfuric acid at 300 deg. C to synthesize sulfonated SWCNTs (s-SWCNTs), which were characterized by electron microscopy, infrared, Raman and X-ray photoelectron spectroscopy, and thermo analysis. Compared with activated carbon, more sulfonic acid groups can be introduced onto the surfaces of SWCNTs. The high degree ({approx}20 wt%) of surface sulfonation led to hydrophilic sidewalls that allows the SWCNTs to be uniformly dispersed in water and organic solvents. The high surface acidity of s-SWCNTs was demonstrated by NH{sub 3} temperature-programmed desorption technique and tested by an acetic acid esterification reaction catalyzed by s-SWCNTs. The results show that the water-dispersive s-SWCNTs are an excellent solid acid catalyst and demonstrate the potential of SWCNTs in catalysis applications. - Graphical abstract: Sulfonated SWCNTs with 20 wt% -SO{sub 2}OH groups were prepared by a high-temperature H{sub 2}SO{sub 4} process, which transformed the hydrophobic surface of pristine SWCNTs to a hydrophilic surface and provided an excellent performance as solid acid catalyst.

Yu Hao [School of Chemical and Energy Engineering, South China University of Technology, Guangzhou 510641 (China)], E-mail: yuhao@scut.edu.cn; Jin Yuguang; Li Zhili [School of Chemical and Energy Engineering, South China University of Technology, Guangzhou 510641 (China); Peng Feng [School of Chemical and Energy Engineering, South China University of Technology, Guangzhou 510641 (China)], E-mail: cefpeng@scut.edu.cn; Wang Hongjuan [School of Chemical and Energy Engineering, South China University of Technology, Guangzhou 510641 (China)

2008-03-15T23:59:59.000Z

488

Fabrication of carbon microcapsules containing silicon nanoparticles-carbon nanotubes nanocomposite by sol-gel method for anode in lithium ion battery  

Science Conference Proceedings (OSTI)

Carbon microcapsules containing silicon nanoparticles (Si NPs)-carbon nanotubes (CNTs) nanocomposite (Si-CNT-C) have been fabricated by a surfactant mediated sol-gel method followed by a carbonization process. Silicon nanoparticles-carbon nanotubes (Si-CNT) nanohybrids were produced by a wet-type beadsmill method. To obtain Si-CNT nanocomposites with spherical morphologies, a silica precursor (tetraethylorthosilicate, TEOS) and polymer (PMMA) mixture was employed as a structure-directing medium. Thus the Si-CNT/Silica-Polymer microspheres were prepared by an acid catalyzed sol-gel method. Then a carbon precursor such as polypyrrole (PPy) was incorporated onto the surfaces of pre-existing Si-CNT/silica-polymer to generate Si-CNT/Silica-Polymer-PPy microspheres. Subsequent thermal treatment of the precursor followed by wet etching of silica produced Si-CNT-C microcapsules. The intermediate silica/polymer must disappear during the carbonization and etching process resulting in the formation of an internal free space. The carbon precursor polymer should transform to carbon shell to encapsulate remaining Si-CNT nanocomposites. Therefore, hollow carbon microcapsules containing Si-CNT nanocomposites could be obtained (Si-CNT-C). The successful fabrication was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). These final materials were employed for anode performance improvement in lithium ion battery. The cyclic performances of these Si-CNT-C microcapsules were measured with a lithium battery half cell tests. - Graphical Abstract: Carbon microcapsules containing silicon nanoparticles (Si NPs)-carbon nanotubes (CNTs) nanocomposite (Si-CNT-C) have been fabricated by a surfactant mediated sol-gel method. Highlights: > Polymeric microcapsules containing Si-CNT transformed to carbon microcapsules. > Accommodate volume changes of Si NPs during Li ion charge/discharge. > Sizes of microcapsules were controlled by experimental parameters. > Lithium storage capacity and coulombic efficiency were demonstrated. > Use of sol-gel procedure as intermediate reaction.

Bae, Joonwon, E-mail: joonwonbae@gmail.com [Samsung Advanced Institute of Technology, Yong-In City 446-712, Gyeong-Gi Province (Korea, Republic of)

2011-07-15T23:59:59.000Z

489

The wavelength dependent photovoltaic effects caused by two different mechanisms in carbon nanotube film/CuO nanowire array heterodimensional contacts  

SciTech Connect

Hetrodimensional contacts were fabricated by coating double-walled carbon nanotube (CNT) films on CuO nanowire arrays. Wavelength dependent photovoltaic effects by irradiating the devices with 405, 532, and 1064 nm lasers were observed. Two possible mechanisms responsible for the observed results were discussed. Photoexcitations within CuO nanowires and Schottky barriers in the heterojunctions dominate the photovoltaics in the 405 and 532 nm cases. For the 1064 nm case, the photovoltaic is the result of the excitation within the CNTs and of the heterodimensionality effect. Control experiments on CNT film/CuO granular film hetrodimensional contacts further show the relationship between these two mechanisms.

Xu Jia; Xu Jinliang [Beijing Key Laboratory of Low-grade Energy Multiphase Flow and Heat Transfer, School of Renewable Energy, North China Electric Power University, Beijing 102206 (China); Sun Jialin [Department of Physics, State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Wei Jinquan [Department of Mechanical Engineering, Key Laboratory for Advanced Materials Processing Technology of Education Ministry, Tsinghua University, Beijing 100084 (China)

2012-06-18T23:59:59.000Z

490

Polyvinylpyrrolidone/Multiwall Carbon Nanotube Composite Based 36 deg. YX LiTaO{sub 3} Surface Acoustic Wave For Hydrogen Gas Sensing Applications  

Science Conference Proceedings (OSTI)

Poly-vinyl-pyrrolidone (PVP)/Multiwall Carbon Nanotubes (MWNTs) based Surface Acoustic Wave (SAW) sensors are fabricated and characterized, and their performances towards hydrogen gas are investigated. The PVP/MWNTs fibers composite are prepared by electrospinning of the composite aqueous solution deposited directly onto the active area of SAW transducers. Via scanning electron microscopy (SEM), the morphology of the deposited nanostructure material is observed. From the dynamic response, frequency shifts of 530 Hz (1%H{sub 2}) and 11.322 kHz (0.25%H{sub 2}) are recorded for the sensors contain of 1.525 g and 1.025 g PVP concentrations, respectively.

Chee, Pei Song; Arsat, Rashidah [Faculty of Electrical Eng and Faculty of Education, Universiti Teknologi Malaysia (Malaysia); He Xiuli [State Key laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing (China); Arsat, Mahyuddin [Faculty of Education, Universiti Teknologi Malaysia (Malaysia); Wlodarski, Wojtek [School of Electrical and Computer Eng. RMIT University, Melbourne (Australia); Kalantar-zadeh, Kourosh

2011-05-25T23:59:59.000Z

491

TiO2 Nanotubes with a ZnO Thin Energy Barrier for Improved Current Efficiency of CdSe Quantum-Dot-Sensitized Solar Cells  

Science Conference Proceedings (OSTI)

This paper reports the formation of a thin ZnO energy barrier between a CdSe quantum dot (Q dots) sensitizer and TiO{sub 2} nanotubes (TONTs) for improved current efficiency of Q dot-sensitized solar cells. The formation of a ZnO barrier between TONTs and the Q dot sensitizer increased the short-circuit current under illumination and also reduced the dark current in a dark environment. The power conversion efficiency of Q dot-sensitized TONT solar cells increased by 25.9% in the presence of the ZnO thin layer due to improved charge-collecting efficiency and reduced recombination.

Lee, W.; Kang, S. H.; Kim, J. Y.; Kolekar, G. B.; Sung, Y. E.; Han, S. H.

2009-01-01T23:59:59.000Z

492

The adsorption effect of C{sub 6}H{sub 5} on density of states for double wall carbon nanotubes by tight binding model  

SciTech Connect

A theoretical approach based on a tight-binding model is developed to study the effects of the adsorption of finite concentrations of C{sub 6}H{sub 5} gas molecules on double-walled carbon nanotube (DWCNT) electronic properties. To obtain proper hopping integrals and random on-site energies for the case of one molecule adsorption, the local density of states for various hopping integrals and random on-site energies are calculated. Since C{sub 6}H{sub 5} molecule is a donor with respect to the carbon nanotubes and their states should appear near the conduction band of the system, effects of various hopping integral deviations and on-site energies for one molecule adsorption are considered to find proper hopping and on-site energies consistent with expected n-type semiconductor. We found that adsorption of C{sub 6}H{sub 5} gas molecules could lead to a (8.0)-(20.0) DWCNT n-type semiconductor. The width of impurity adsorbed gas states in the density of states could be controlled by adsorbed gas concentration.

Fathalian, A., E-mail: a.fathalian@gmail.com [Razi University, Department of Physics (Iran, Islamic Republic of)

2012-06-15T23:59:59.000Z

493

Self-Organized Amorphous TiO2 Nanotube Arrays on Porous Ti Foam for Rechargeable Lithium and Sodium Ion Batteries  

SciTech Connect

Self-organized amorphous TiO2 nanotube arrays (NTAs) were successfully fabricated on both Ti foil and porous Ti foam through electrochemical anodization techniques. The starting Ti foams were fabricated using ARCAM s Electron Beam Melting (EBM) technology. The TiO2 NTAs on Ti foam were used as anodes in lithium ion batteries; they exhibited high capacities of 103 Ahcm-2 at 10 Acm-2 and 83 Ahcm-2 at 500 Acm-2, which are two to three times higher than those achieved on the standard Ti foil, which is around 40 Ahcm-2 at 10 Acm-2 and 24 Ahcm-2 at 500 Acm-2, respectively. This improvement is mainly attributed to higher surface area of the Ti foam and higher porosity of the nanotube arrays layer grown on the Ti foam. In addition, a Na-ion half-cell composed of these NTAs anodes and Na metal showed a self-improving specific capacity upon cycling at 10 Acm-2. These results indicate that TiO2 NTAs grown on Ti porous foam are promising electrodes for Li-ion or Na-ion rechargeable batteries.

Bi, Zhonghe [ORNL; Paranthaman, Mariappan Parans [ORNL; Menchhofer, Paul A [ORNL; Dehoff, Ryan R [ORNL; Bridges, Craig A [ORNL; Chi, Miaofang [ORNL; Guo, Bingkun [ORNL; Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL

2013-01-01T23:59:59.000Z

494

Characterization of fundamental catalytic properties of MoS2/WS2 nanotubes and nanoclusters for desulfurization catalysis - a surface temperature study  

DOE Green Energy (OSTI)

The prior project consisted of two main project lines. First, characterization of novel nanomaterials for hydrodesulfurization (HDS) applications. Second, studying more traditional model systems for HDS such as vapor-deposited silica-supported Mo and MoSx clusters. In the first subproject, we studied WS2 and MoS2 fullerene-like nanoparticles as well as WS2 nanotubes. Thiophene (C4H4S) was used as the probe molecule. Interestingly, metallic and sulfur-like adsorption sites could be identified on the silica-supported fullerene-particles system. Similar structures are seen for the traditional system (vapor-deposited clusters). Thus, this may be a kinetics fingerprint feature of modern HDS model systems. In addition, kinetics data allowed characterization of the different adsorption sites for thiophene on and inside WS2 nanotube bundles. The latter is a unique feature of nanotubes that has not been reported before for any inorganic nanotube system; however, examples are known for carbon nanotubes, including prior work of the PI. Although HDS has been studied for decades, utilizing nanotubes as nanosized HDS reactors has never been tried before, as far as we know. This is of interest from a fundamental perspective. Unfortunately, the HDS activity of the nanocatalysts at ultra-high vacuum (UHV) conditions was close to the detection limit of our techniques. Therefore, we propose to run experiments at ambient pressure on related nanopowder samples as part of the renewal application utilizing a now-available GC (gas chromatograph) setup. In addition, Ni and Co doped nanocatalyts are proposed for study. These dopants will boost the catalytic activity. In the second subproject of the prior grant, we studied HDS-related chemistry on more traditional supported cluster catalysts. Mo clusters supported by physical vapor deposition (PVD) on silica have been characterized. Two reaction pathways are evident when adsorbing thiophene on Mo and MoSx clusters: molecular adsorption and dissociation. PVD Mo clusters turned out to be very reactive toward thiophene bond activation. Sulfur and carbon residuals form, which poison the catalyst and sulfide the Mo clusters. Sulfided silica-supported MoSx samples are not reactive toward thiophene bond activation. In addition to S and C deposits, H2, H2S, and small organic molecules were detected in the gas phase. Catalyst reactivation procedures, including O2 and atomic hydrogen treatments, have been tested. Cluster size effects have been seen: thiophene adsorbs molecularly with larger binding energies on smaller clusters. However, larger clusters have smaller activation energy for C4H4S bond activation than smaller clusters. The latter is consistent with early catalysis studies. Kinetics and dynamics parameters have been determined quantitatively. We spent a significant amount of time on upgrades of our equipment. A 2nd-hand refurbished X-ray photoelectron spectrometer (XPS) has been integrated into the existing molecular beam scattering system and is already operational (supported by the DoE supplemental grant available in October 2009). We also added a time of flight (TOF) system to the beam scattering apparatus and improved on the accessible impact energy range (new nozzle heater and gas mixing manifold) for the beam scattering experiments. In addition, a GC-based powder atmospheric flow reactor for studies on powder samples is now operational. Furthermore, a 2nd UHV kinetics system has been upgraded as well. In summary, mostly single crystal systems have so far been considered in basic science studies about HDS. Industrial catalysts, however, can be better approximated with the supported cluster systems that we studied in this project. Furthermore, an entirely new class of HDS systems, namely fullerene-like particles and inorganic nanotubes, has been included. Studying new materials and systems has the potential to impact science and technology. The systems investigated are closely related to energy and environmental-related surface science/catalysis. This prior project, conducted at NDSU by a sma

U. Burghaus

2012-07-05T23:59:59.000Z

495

CarbonNanotubeActive ...  

intensively explored for enabling new applications otherwise ... Of particular importance, a high mobility, such as those obtained here, ...

496

Nanotube Composite Anode Materials  

Increased battery capacity, safety, ... Electric and plug-in hybrid electric vehicles; Portable electronic devices; Medical devices; and

497

Mechanomutable Carbon Nanotube Arrays  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2010 TMS Annual Meeting & Exhibition. Symposium , Polymer Nanocomposites. Presentation Title, Mechanomutable Carbon ...

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