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1

Efficient synthesis of dimethyl carbonate via transesterification of ethylene carbonate with methanol over binary zinc-yttrium oxides  

Microsoft Academic Search

The binary zinc–yttrium oxides were prepared by co-precipitation method, characterized and tested in the synthesis of DMC via transesterification of ethylene carbonate with methanol. The catalytic results showed that the catalyst with Zn\\/Y molar ratio of 3 and calcined at 400°C exhibited superior catalytic activity, corresponding to TOF of 236mmol\\/gcath. Appropriate content of yttrium in the catalyst enhanced the catalytic

Liguo Wang; Ying Wang; Shimin Liu; Liujin Lu; Xiangyuan Ma; Youquan Deng

2011-01-01

2

Effect of yttrium and chromium ion implantation on crevice electrochemical behavior of carbon steel in sodium chloride solution  

Microsoft Academic Search

In order to study the effect of yttrium (Y) and chromium (Cr) ion implantation on the crevice corrosion behavior of carbon steel, the carbon steel was implanted with Y and Cr ion using MEVVA source at an energy of 40keV. Electrochemical measurement was employed to evaluate the crevice corrosion of implanted carbon steel in NaCl solution. The results indicated that,

Chenghao Liang; Naibao Huang

2008-01-01

3

The inhibition of neuronal calcium ion channels by trace levels of yttrium released from carbon nanotubes  

PubMed Central

Carbon nanotubes (CNTs) are used with increasing frequency in neuroengineering applications. CNT scaffolds are used to transmit electrical stimulation to cultured neurons and to control outgrowth and branching patterns of neurites. CNTs have been reported to disrupt normal neuronal function including alterations in endocytotic capability and inhibition of ion channels. Calcium ion channels regulate numerous neuronal and cellular functions including endo and exocytosis, neurite outgrowth, and gene expression. Strong CNT interactions with neuronal calcium ion channels would have profound biological implications. Here we show that physiological solutions containing CNTs inhibit neuronal voltage-gated calcium-ion channels in a dose dependent and CNT-sample-dependent manner with IC50 as low as 1.2 ug/ml. Importantly, we demonstrate that the inhibitory activity does not involve tubular graphene as previously reported, but rather very low concentrations of soluble yttrium released from the nanotube growth catalyst. Cationic yttrium potently inhibits calcium ion channel function with an inhibitory efficacy, IC50, of 0.07 ppm w/w. Because of this potency, unpurified and even some reportedly “purified” CNT samples contain sufficient bioavailable yttrium to inhibit channel function. Our results have important implications for emerging nano-neurotechnology and highlight the critical role that trace components can play in the biological response to complex nanomaterials.

Jakubek, Lorin; Marangoudakis, Spiro; Raingo, Jessica; Liu, Xinyuan; Lipscombe, Diane; Hurt, Robert

2009-01-01

4

Small yttrium-carbon and lanthanum-carbon clusters: Rings are most stable  

SciTech Connect

A theoretical study has been undertaken to determine the energetics of a variety of neutral and cationic isomeric forms of metal clusters MC{sub x}, where M = Y or La and x = 3-6. Included in this study are cyclic molecules and linear molecules, as well as recently-proposed `kite` structures. Geometries are optimized by the B3LYP density functional method, and energies are computed with the coupled-cluster method. The major conclusion of this work is that cyclic structures are the most stable, a result which holds for both yttrium and lanthanum and for both cations and neutral molecules. 19 refs., 1 fig., 2 tabs.

Strout, D.L.; Hall, M.B. [Texas A& M Univ., College Station, TX (United States)] [Texas A& M Univ., College Station, TX (United States)

1996-11-14

5

Enrichment of yttrium from rare earth concentrate by ammonium carbonate leaching and peroxide precipitation  

Microsoft Academic Search

The rare earth elements (REE) solubility with ammonium carbonate vary progressively from element to element, the heavy rare earth elements (HRE) being more soluble than the light rare earth elements (LRE). Their solubility is function of the carbonate concentration and the kind of carbonate as sodium, potassium and ammonium. In this work, it is explored this ability of the carbonate

Mari E. de Vasconcellos; S. M. R. da Rocha; W. R. Pedreira; Carlos A. da S. Queiroz; Alcídio Abrão

2006-01-01

6

Oxygen vacancy induced carbon deposition at the triple phase boundary of the nickel/yttrium-stabilized zirconia (YSZ) interface  

NASA Astrophysics Data System (ADS)

The carbon deposition at the Triple Phase Boundary (TPB) of the Nickel/Yttrium-Stabilized Zirconia (YSZ) interface is studied using the first-principles method based on density functional theory, with consideration of the interface oxygen vacancy. It is found that the CH fragment (the most stable dissociation products of CH4 on Ni catalyst) can easily diffuse and be trapped at the O vacancy. The trapped CH can dissociate to C and H with a much lower dissociation barrier (0.74 eV) as compared with that (1.39 eV) on the pure Ni (111) surface. Therefore, we propose that the carbon deposition may form easily at the interface oxygen vacancy of TPB as compared with that on the pure Ni (111) surface, which offers new understanding on the carbon deposition of the Ni/YSZ anode of solid oxide fuel cell.

Zhang, Yanxing; Fu, Zhaoming; Wang, Mingyang; Yang, Zongxian

2014-09-01

7

Effect of yttrium and chromium ion implantation on crevice electrochemical behavior of carbon steel in sodium chloride solution  

NASA Astrophysics Data System (ADS)

In order to study the effect of yttrium (Y) and chromium (Cr) ion implantation on the crevice corrosion behavior of carbon steel, the carbon steel was implanted with Y and Cr ion using MEVVA source at an energy of 40 keV. Electrochemical measurement was employed to evaluate the crevice corrosion of implanted carbon steel in NaCl solution. The results indicated that, after Y and Cr ion implantation, the carbon steel's crevice corrosion resistance and electrochemical characteristic were significantly improved in NaCl solution when the implantation dose of Y increased. Auger electron spectroscopy (AES) analysis of the implanted carbon steel manifested that the surface layer was mainly composed of elements Fe, Cr, O, and Y. Most of element Y was located near the outside region of the surface layer/solution interface, whereas Cr was enriched in the transition area between surface layer and matrix. By X-ray photoelectron spectroscopy (XPS) analysis, the implanted Y was in the form of Y 2O 3, whereas Cr in the form of Cr 2O 3 in the surface layer. The mechanism of the crevice corrosion resistance and electrochemical characteristic improvement was that, after Y and Cr ion implantation, the surface layer seemed to be constituted by Y 2O 3 and Cr 2O 3. The surface layer acted as a barrier to reduce the metal matrix to contact with the corrosion medium such as inhibiting Cl - ions from corroding the layer.

Liang, Chenghao; Huang, Naibao

2008-12-01

8

Ablative laser resurfacing: high-energy pulsed carbon dioxide and erbium:yttrium-aluminum-garnet  

Microsoft Academic Search

The development of the short-pulsed high-energy carbon dioxide laser in the mid 1990's led to the emergence of laser skin resurfacing. Used in the continuous mode, the CO2 laser can cut and coagulate simultaneously. Used in the pulsed mode, the CO2 laser is a powerful tool for epidermal ablation in many different contexts both therapeutic and cosmetic. Both the CO2

Karen Riggs; Matthew Keller; Tatyana R. Humphreys

2007-01-01

9

Doping-free fabrication of n-type random network single-walled carbon nanotube field effect transistor with yttrium contacts  

Microsoft Academic Search

This work reports the realization of high performance n-type random network single-walled carbon nanotube (rn-SWCNT) field effect transistor (FET) by means of contact engineering, where a low work function metal, Yttrium (Y), is used as the source and drain contacts. The presence of crossed metallic (m-) and semiconducting (s-) SWCNT junctions in the channel of rn-SWCNT FETs, which form p-type

Leihua Huang; Eng Fong Chor; Yihong Wu

2011-01-01

10

Generation, properties, and order packing of monodispersed spherical colloid particles of yttrium hydroxy-carbonate: A colloidal route to minimizing voids in ceramics  

SciTech Connect

Yttrium hydroxy-carbonate particles were prepared by decomposition of urea in yttrium nitrate solutions. The nucleation and growth were studied in silica-seeded and unseeded systems. Precipitation took place only under neutral conditions. In unseeded systems, homogeneous nucleation yielded 3 x 10/sup 10/ nucleicm/sup 3/ while in seeded precipitation enough nuclei were produced to bring the total number of particles to 4 x 10/sup 10/cm/sup 3/. Systems containing at least 4 x 10/sup 10/ seedscm/sup 3/ underwent pure heterogeneous precipitation onto the existing seeds. Two diffusion-controlled growth models and the diffusion chronomal analysis were applied to the data of growth rate. Results confirmed the diffusion-controlled particle growth mechanism. Electron diffraction showed the particles to be crystalline. Electrophoresis showed a charge reversal from positive to negative with pH, with an isoelectric point of about 7.4. The chemical composition of the powders was determined to be Y(OH)CO/sub 3/ . H/sub 2/O. Stability of aqueous suspensions was studied as a function of pH. 74 refs., 27 figs., 3 tabs

Mwesigwa-Kayima, P.

1987-11-01

11

Doping-free fabrication of n-type random network single-walled carbon nanotube field effect transistor with yttrium contacts  

NASA Astrophysics Data System (ADS)

This work reports the realization of high performance n-type random network single-walled carbon nanotube (rn-SWCNT) field effect transistor (FET) by means of contact engineering, where a low work function metal, Yttrium (Y), is used as the source and drain contacts. The presence of crossed metallic ( m-) and semiconducting ( s-) SWCNT junctions in the channel of rn-SWCNT FETs, which form p-type rectifying Schottky barrier, is believed to introduce non-negligible hole current in the fabricated FETs and lead to undesirable ambipolar characteristic. By means of soaking in 2,4,6-triphenylpyrylium tetrafluoroborate (2,4,6-TPPT), we have successfully converted the ambipolar rn-SWCNT FETs to highly unipolar n-type devices by selectively removing the m-SWCNTs in the FET channel. The best characteristics of our unipolar n-type rn-SWCNT FETs are as follows: on/off current ratio up to ?10 5, mobility as high as 25 cm 2 V -1 s -1, and transconductance of 0.12 ?S/?m; they have demonstrated air-stable n-type characteristics and are also more reproducibility than individual SWCNT FETs.

Huang, Leihua; Chor, Eng Fong; Wu, Yihong

2011-05-01

12

carbon cycle  

NSDL National Science Digital Library

Life on earth is based on carbon. Living things acquire carbon from their environment - from air, water, soil, and rock and from other living things - through processes such as photosynthesis, respiration and decomposition. The carbon cycle model is a representation of the movement of carbon from sources to sinks through chemical and physical transfers. The carbon cycle activity allows students to see the effect of fossil fuel burning on the carbon cycle.

School, Maryland V.

13

Carbon-carbon cylinder block  

NASA Technical Reports Server (NTRS)

A lightweight cylinder block composed of carbon-carbon is disclosed. The use of carbon-carbon over conventional materials, such as cast iron or aluminum, reduces the weight of the cylinder block and improves thermal efficiency of the internal combustion reciprocating engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall clearance can be small, especially when the carbon-carbon cylinder block is used in conjunction with a carbon-carbon piston. Use of the carbon-carbon cylinder block has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance.

Ransone, Philip O. (Inventor)

1998-01-01

14

Carbon Smackdown: Carbon Capture  

SciTech Connect

In this July 9, 2010 Berkeley Lab summer lecture, Lab scientists Jeff Long of the Materials Sciences and Nancy Brown of the Environmental Energy Technologies Division discuss their efforts to fight climate change by capturing carbon from the flue gas of power plants, as well as directly from the air

Jeffrey Long

2010-07-12

15

Carbon Smackdown: Carbon Capture  

ScienceCinema

In this July 9, 2010 Berkeley Lab summer lecture, Lab scientists Jeff Long of the Materials Sciences and Nancy Brown of the Environmental Energy Technologies Division discuss their efforts to fight climate change by capturing carbon from the flue gas of power plants, as well as directly from the air

16

Carbon Smackdown: Carbon Capture  

ScienceCinema

In this July 9, 2010 Berkeley Lab summer lecture, Lab scientists Jeff Long of the Materials Sciences and Nancy Brown of the Environmental Energy Technologies Division discuss their efforts to fight climate change by capturing carbon from the flue gas of power plants, as well as directly from the air

Jeffrey Long

2010-09-01

17

Carbon Configurations  

NSDL National Science Digital Library

In this activity, learners use geometry to predict the shape of carbon. Learners twist and attach chenille stem pieces that represent bonds between different carbon atoms. Information about tetrahedral, trigonal planar, and diamond geometry types is included in this resource. This activity can also be used to introduce learners to allotropes (pure carbon forms) and fullerenes such as buckyballs and carbon nanotubes.

Yu, Julie

2010-01-01

18

Carbon-carbon piston development  

NASA Technical Reports Server (NTRS)

A new piston concept, made of carbon-carbon refractory-composite material, has been developed that overcomes a number of the shortcomings of aluminum pistons. Carbon-carbon material, developed in the early 1960's, is lighter in weight than aluminum, has higher strength and stiffness than aluminum and maintains these properties at temperatures over 2500 F. In addition, carbon-carbon material has a low coefficient of thermal expansion and excellent resistance to thermal shock. An effort, called the Advanced Carbon-Carbon Piston Program was started in 1986 to develop and test carbon-carbon pistons for use in spark ignition engines. The carbon-carbon pistons were designed to be replacements for existing aluminum pistons, using standard piston pin assemblies and using standard rings. Carbon-carbon pistons can potentially enable engines to be more reliable, more efficient and have greater power output. By utilizing the unique characteristics of carbon-carbon material a piston can: (1) have greater resistance to structural damage caused by overheating, lean air-fuel mixture conditions and detonation; (2) be designed to be lighter than an aluminum piston thus, reducing the reciprocating mass of an engine, and (3) be operated in a higher combustion temperature environment without failure.

Gorton, Mark P.

1994-01-01

19

Glassy Carbons.  

National Technical Information Service (NTIS)

A large number of glassy carbon samples was produced by controlled pyrolysis of furfural alcohol resins, examined for structural differences, and evaluated for physical and mechanical properties. It is concluded that glassy carbon is a family of materials...

E. E. Hucke

1973-01-01

20

Carbon Sequestration  

NSDL National Science Digital Library

In this inquiry-based lesson, learners measure the biomass of trees, calculate the carbon stored by the trees, and use this information to create recommendations about using trees for carbon sequestration. This activity encourages learners to think critically about managing forests for carbon sequestration.

Science, New Y.

2012-01-01

21

Carbon Footprint  

NSDL National Science Digital Library

This website has interactive tools to calculate your carbon footprint, which is a way to measure how much carbon dioxide and other greenhouse gases are produced by your activities. This site also contains specific recommendations for reducing and off-setting your carbon footprint, as well as links to news and information about global warming.

Ltd, Carbon F.

22

Carbon-Carbon Piston Architectures  

NASA Technical Reports Server (NTRS)

An improved structure for carbon-carbon composite piston architectures consists of replacing the knitted fiber, three-dimensional piston preform architecture described in U.S. Pat. No. 4.909,133 (Taylor et al.) with a two-dimensional lay-up or molding of carbon fiber fabric or tape. Initially. the carbon fabric or tape layers are prepregged with carbonaceous organic resins and/or pitches and are laid up or molded about a mandrel. to form a carbon-fiber reinforced organic-matrix composite part shaped like a "U" channel, a "T"-bar. or a combination of the two. The molded carbon-fiber reinforced organic-matrix composite part is then pyrolized in an inert atmosphere, to convert the organic matrix materials to carbon. At this point, cylindrical piston blanks are cored from the "U" channel, "T"-bar, or combination part. These blanks are then densified by reimpregnation with resins or pitches which are subsequently carbonized. Densification is also be accomplished by direct infiltration with carbon by vapor deposition processes. Once the desired density has been achieved, the piston billets are machined to final piston dimensions; coated with oxidation sealants; and/or coated with a catalyst. When compared to conventional steel or aluminum-alloy pistons, the use of carbon-carbon composite pistons reduces the overall weight of the engine; allows for operation at higher temperatures without a loss of strength; allows for quieter operation; reduces the heat loss; and reduces the level of hydrocarbon emissions.

Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor); Schwind, Francis A. (Inventor)

1999-01-01

23

Carbon-Carbon Piston Architectures  

NASA Technical Reports Server (NTRS)

An improved structure for carbon-carbon composite piston architectures is disclosed. The improvement consists of replacing the knitted fiber, three-dimensional piston preform architecture described in U.S. Pat.No. 4,909,133 (Taylor et al.) with a two-dimensional lay-up or molding of carbon fiber fabric or tape. Initially, the carbon fabric of tape layers are prepregged with carbonaceous organic resins and/or pitches and are laid up or molded about a mandrel, to form a carbon-fiber reinforced organic-matrix composite part shaped like a "U" channel, a "T"-bar, or a combination of the two. The molded carbon-fiber reinforced organic-matrix composite part is then pyrolized in an inert atmosphere, to convert the organic matrix materials to carbon. At this point, cylindrical piston blanks are cored from the "U"-channel, "T"-bar, or combination part. These blanks are then densified by reimpregnation with resins or pitches which are subsequently carbonized. Densification is also accomplished by direct infiltration with carbon by vapor deposition processes. Once the desired density has been achieved, the piston billets are machined to final piston dimensions; coated with oxidation sealants; and/or coated with a catalyst. When compared to conventional steel or aluminum alloy pistons, the use of carbon-carbon composite pistons reduces the overall weight of the engine; allows for operation at higher temperatures without a loss of strength; allows for quieter operation; reduces the heat loss; and reduces the level of hydrocarbon emissions.

Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor); Schwind, Francis A. (Inventor)

2000-01-01

24

Carbon sequestration.  

PubMed

Developing technologies to reduce the rate of increase of atmospheric concentration of carbon dioxide (CO2) from annual emissions of 8.6PgCyr-1 from energy, process industry, land-use conversion and soil cultivation is an important issue of the twenty-first century. Of the three options of reducing the global energy use, developing low or no-carbon fuel and sequestering emissions, this manuscript describes processes for carbon (CO2) sequestration and discusses abiotic and biotic technologies. Carbon sequestration implies transfer of atmospheric CO2 into other long-lived global pools including oceanic, pedologic, biotic and geological strata to reduce the net rate of increase in atmospheric CO2. Engineering techniques of CO2 injection in deep ocean, geological strata, old coal mines and oil wells, and saline aquifers along with mineral carbonation of CO2 constitute abiotic techniques. These techniques have a large potential of thousands of Pg, are expensive, have leakage risks and may be available for routine use by 2025 and beyond. In comparison, biotic techniques are natural and cost-effective processes, have numerous ancillary benefits, are immediately applicable but have finite sink capacity. Biotic and abiotic C sequestration options have specific nitches, are complementary, and have potential to mitigate the climate change risks. PMID:17761468

Lal, Rattan

2008-02-27

25

Manual of carbonate sedimentology  

SciTech Connect

This manual, organised along encycolopaedic/lexicographic lines, summarizes information on the properties and characteristics of carbonates and their environments. Part 1 deals with the elements of carbonates; Part 2 with environments, settings, and carbonate bodies; Part 3 with carbonate diagenesis, and Part 4 with carbonate reservoirs. Contents include: Elements of carbonates; Carbonate Environments, Settings and Bodies; Carbonate diagenesis; Carbonate reservoirs; Alphabetical Indices; English, Dutch, German, Spanish, French Computer Compatible Codes; Commonly Used (Informal) abbreviations.

Reijers, T.J.; Hsu, K.S.

1986-01-01

26

Carbon particles  

DOEpatents

A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

Hunt, Arlon J. (Oakland, CA)

1984-01-01

27

Carbon microtubes  

DOEpatents

A carbon microtube comprising a hollow, substantially tubular structure having a porous wall, wherein the microtube has a diameter of from about 10 .mu.m to about 150 .mu.m, and a density of less than 20 mg/cm.sup.3. Also described is a carbon microtube, having a diameter of at least 10 .mu.m and comprising a hollow, substantially tubular structure having a porous wall, wherein the porous wall comprises a plurality of voids, said voids substantially parallel to the length of the microtube, and defined by an inner surface, an outer surface, and a shared surface separating two adjacent voids.

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

2011-06-14

28

Carbon Nanoelectronics  

NASA Astrophysics Data System (ADS)

Recently, there has been tremendous interest in nanostructures built entirely out of carbon. The most famous are the soccer-ball shaped C60 molecule and single-walled nanotubes. The latter are nanometer-diameter cylinders made from rolled up single graphene sheets. These carbon nanostructures are proving to be wonderful systems for the study of the physics of electrons in reduced dimensions. They also have a variety of technological applications (both demonstrated and potential), in areas ranging from materials to electronics to biotechnology. In this talk, I will discuss our group's recent efforts to probe the electrical and electromechanical, and thermal properties of these fascinating systems. note

McEuen, Paul

2001-05-01

29

Carbon dioxide  

NSDL National Science Digital Library

Bubbles are an indicator of a chemical reaction. An indicator is an object, material, or organism that tells you if a specific substance is present. In the sugar test, carbon dioxide gas release is an indicator that yeast is using sugar to grow. The more gas produced, the more sugar a specific substance contains.

Arie Melamed-Katz (None;)

2007-06-19

30

Black Carbon  

NSDL National Science Digital Library

Black carbon, composed of tiny particles of soot, is produced whenever organic substances like fossil fuels, firewood or coal is incompletely burned. These particles are polluting the air and causing serious health and environmental concerns for people around the world. "Changing Planet" is produced in partnership with the National Science Foundation.

Learn, Nbc

2010-10-07

31

Carbon coal  

Microsoft Academic Search

The Carbon Coal Co. mines one million tons of coal per year from thin seams. In this arid area water requirements for coal washing are met by using treated waste water from Gallup's municipal waste treatment plant for which they pay 5 cents per 1000 gallons.

1981-01-01

32

Carbon Research.  

National Technical Information Service (NTIS)

The pyrolytic carbons deposited in fluidized beds are a new family of carbonaceous materials with structures and properties that can be controlled over wide ranges. One of the objectives of the present work was to develop a better understanding of the rel...

F. J. Schoen J. C. Bokros J. L. Kaae R. J. Akins R. J. Price

1972-01-01

33

Novel carbon fiber based porous carbon monolith.  

National Technical Information Service (NTIS)

A novel porous carbon material based on carbon fibers has been developed. The material, when activated, develops a significant micro- or mesopore volume dependent upon the carbon fiber type utilized (isotropic pitch or polyacrylonitrile). The materials wi...

T. D. Burchell J. W. Klett C. E. Weaver

1995-01-01

34

Carbon-carbon - An overview  

NASA Technical Reports Server (NTRS)

In nonoxidizing high-temperature environments, carbon-carbon composites retain room temperature properties to more than 2225 C; in oxidizing environments, the variety of coatings thus far developed limits maximum operating temperatures to about 1600 C. The high thermal conductivity and low thermal expansion of these composites renders them ideal for applications encountering thermal shocks. In addition, the variety of fibers, weave patterns, and layup procedures that can be used for the composites allows mechanical properties to be carefully tailored over a wide range to fit the application in question.

Buckley, John D.

1988-01-01

35

Glassy Carbons, Alloys.  

National Technical Information Service (NTIS)

Contents: Compositional and structural modification of glassy carbons; Spherulitic glassy carbon; Preparation of glassy carbon with open macroporosity and its infiltration; Preparation and characterization of binary carbon-based glasses by RF-sputtering.

P. L. Walker

1974-01-01

36

Carbon takeoff [carbon fiber composites  

Microsoft Academic Search

This paper describes the novel design of Boeing's new 787 Dreamliner, which showcases a fuselage and wings made almost entirely of carbon-fiber composites. The composite wing is lighter and more resistant to fatigue and corrosion than aluminum wings, and will help save fuel and lower maintenance costs. More than just another all-new plane, the 787 represents an evolutionary transition for

E. Guizzo

2006-01-01

37

Carbon City  

NSDL National Science Digital Library

Since the Industrial Revolution, atmospheric carbon dioxide concentration has risen from ~280ppm (parts per million by volume) to ~390ppm in 2010. The rate of increase for the last decade (2001-2010) has been 2.04ppm/yr, more than double the rate for the 1960's. Most scientists agree that human actions are the primary cause of the increase, the rise in Earth's average temperature since the mid-1900's and recent climate change. In this problem-based learning activity, learners develop a carbon mitigation strategy to address climate change issues. This module was developed to be used in the Earth System Science Education Alliance (ESSEA) courses for middle and high school teachers and is also available to teachers to adapt for general classroom use.

38

Carbon Cycle  

NSDL National Science Digital Library

Elementary students often successfully memorize and repeat back the stages in cycles, with no deep conceptual understanding of the complexities of the processes involved. Their ability to synthesize knowledge of the cycles with a wider breadth of information related to real-world, unresolved environmental issues such as global warming, greenhouse gas emissions or the burning of biomass for fuel is probably less well developed. In order to engage in meaningful discussions of carbon-related environmental issues, students also need an understanding of the changing nature of the earth s atmosphere. The relative proportion of nitrogen, carbon dioxide, oxygen, ozone and other gases is neither consistent around the world nor constant over time. What factors contribute to the variability in atmospheric content? Which of the factors should be controlled? What are the possible approaches to controlling them? What are the possible and probable outcomes of such controlling measures?

Lefever, Mary

2007-01-01

39

Carbon "Kidprints"  

NSDL National Science Digital Library

In this self-paced tutorial, learners explore the personal choices students make every day as resource consumers, and how those decisions contribute to the climate health of our planet. Multimedia educational resources such as video clips, digital interactive explorations and a quiz are included. This is the fifth of ten self-paced professional development modules providing opportunities for teachers to learn about climate change through first-hand data exploration. A carbon consumption calculator designed for kids to be used in the classroom and glossary links to vocabulary are included.

40

Carbonic inclusions  

NASA Astrophysics Data System (ADS)

The paper gives an overview of the phase relations in carbonic fluid inclusions with pure, binary and ternary mixtures of the system CO 2-CH 4-N 2, compositions, which are frequently found in geological materials. Phase transitions involving liquid, gas and solid phases in the temperature range between -192°C and 31°C are discussed and presented in phase diagrams ( PT, TX and VX projections). These diagrams can be applied for the interpretation of microthermometry data in order to determine fluid composition and molar volume (or density).

Van den Kerkhof, Alfons; Thiéry, Régis

2001-01-01

41

Trading forest carbon  

EPA Science Inventory

The nature of carbon in forests is discussed from the perspective of carbon trading. Carbon inventories, specifically in the area of land use and forestry are reviewed for the Pacific Northwest. Carbon turnover in forests is discussed as it relates to carbon sequestration. Scient...

42

Capturing Carbon Dioxide  

NSDL National Science Digital Library

In this activity, learners investigate carbon sequestration by creating a carbonated beverage out of apple juice and dry ice. This experiment illustrates how carbon dioxide can be stored in a substance. Learners compare and contrast the results to determine if liquid carbonation is an effective method for carbon sequestration. Safety note: this activity involves dry ice; please follow recommended guidelines.

Saltz, Austen

2010-01-01

43

Superhydrophobic amorphous carbon/carbon nanotube nanocomposites  

NASA Astrophysics Data System (ADS)

Superhydrophobic amorphous carbon/carbon nanotube nanocomposites are fabricated by plasma immersion ion implantation with carbon nanotube forests as a template. The microstructure of the fabricated nanocomposites shows arrays of carbon nanotubes capped with amorphous carbon nanoparticles. Contact angle measurements show that both advancing and receding angles close to 180° can be achieved on the nanocomposites. The fabrication here does not require patterning of carbon nanotubes or deposition of conformal coatings with low surface energy, which are usually involved in conventional approaches for superhydrophobic surfaces. The relationship between the observed superhydrophobicity and the unique microstructure of the nanocomposites is discussed.

Han, Z. J.; Tay, B. K.; Shakerzadeh, M.; Ostrikov, K.

2009-06-01

44

Carbonate acidizing  

SciTech Connect

The authors present the first quantitative study and complete model of the wormholing phenomenon, leading to a means of predicting and optimizing carbonate acidizing treatments. Laboratory experiments on a gypsum model system and computer simulations show that for a given geometry, wormholes can be quantified by a unique parameter, their equivalent hydraulic length. The behavior of this quantifying parameter vs. all the system parameters is studied and allows the quantitative prediction of the efficiency of an acidizing treatment. This study highlights the fractal nature of the phenomenon, which is accounted for in the equations, and the strong effect of the sample geometry. Three types of etching can be obtained: compact, wormhole type, or homogeneous. The optimum conditions for achieving the best skin decrease correspond to the creation of wormholes and can then be defined in terms of fluid reactivity and injection rate.

Daccord, G.; Touboul, E.; Lenormand, R.

1989-02-01

45

Carbon dioxide concentrator  

NASA Technical Reports Server (NTRS)

Passed exhaled air through electrochemical cell containing alkali metal carbonate aqueous solution, and utilizes platinized electrodes causing reaction of oxygen at cathode with water in electrolyte, producing hydroxyl ions which react with carbon dioxide to form carbonate ions.

Williams, C. F.; Huebscher, R. G.

1972-01-01

46

Method of making carbon-carbon composites  

DOEpatents

A process for making 2D and 3D carbon-carbon composites having a combined high crystallinity, high strength, high modulus and high thermal and electrical conductivity. High-modulus/high-strength mesophase derived carbon fibers are woven into a suitable cloth. Layers of this easily graphitizible woven cloth are infiltrated with carbon material to form green composites. The carbonized composite is then impregnated several times with pitch by covering the composite with hot pitch under pressure. The composites are given a heat treatment between each impregnant step to crack up the infiltrated carbon and allow additional pitch to enter the microstructure during the next impregnation cycle. The impregnated composites are then given a final heat treatment in the range 2500.degree. to 3100.degree. C. to fully graphitize the fibers and the matrix carbon. The composites are then infiltrated with pyrolytic carbon by chemical vapor deposition in the range 1000.degree. C. to 1300.degree. C. at a reduced. pressure.

Engle, Glen B. (16716 Martincoit Rd., Poway, CA 92064)

1993-01-01

47

Carbon structures in silicon carbide derived carbon  

Microsoft Academic Search

Carbide derived carbon (CDC) produced by etching SiC in halogens has been investigated using transmission electron microscopy (TEM). Depending on experimental conditions, CDC may contain sp3- or sp2-bonded carbon phases. Amorphous carbon, poorly ordered turbostratic carbon with lattice spacing exceeding values of 0.35nm as well as highly ordered graphite were observed. sp3-Bonded structures consist of mainly lonsdaleite and cubic diamond

Sascha Welz; Michael J. McNallan; Yury Gogotsi

2006-01-01

48

Carbon Capture (Carbon Cycle 2.0)  

ScienceCinema

Berend Smit speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 3, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

Smit, Berend

2011-06-08

49

Interpreting carbon-isotope excursions: carbonates and organic matter  

Microsoft Academic Search

Variations in the carbon isotopic compositions of marine carbonate and organic carbon provide a record of changes in the fraction of organic carbon buried through time and may provide clues to changes in rates of weathering and sources of organic carbon. Paired carbonate and organic carbon isotope determinations provide a possibility of interpreting not only changes in the global carbon

Lee R. Kump; Michael A. Arthur

1999-01-01

50

Carbon Residence Times in Pedogenic Carbonate Pools  

NASA Astrophysics Data System (ADS)

Soil carbonate is a huge pool of terrestrial carbon that contains at least 930 to 940 Pg C and has influx rates on the order of 1 to 12 g CaCO3/m2/yr. Such large mass to flux ratios yield long mean residence times for carbon (e.g., 85,000 years)--assuming steady state. Like other global carbon pools, the soil carbonate pool has smaller sub-pools with higher influx rates and shorter mean residence times. For example, pedogenic carbonate in coppice dunes known to have formed since 1858 and carbonate formed on lithic artifacts in soils at archaeology sites suggests mean residence times can be as short as 120 years--again assuming steady state. Harder to assess are efflux rates as CO2 emissions or bicarbonate leaching. Some Bowen-ratio studies have nevertheless found evidence for CO2 emissions resulting from carbonate dissolution, and other studies have found evidence for bicarbonate leaching based on dissolution pipes through calcic horizons using soil morphology studies. Since an understanding of mean residence times are prerequisite for a better understanding of soil carbonate in the global carbon cycle, especially in a scenario of an expanding Aridosphere, more influx and efflux measurements are needed to evaluate the possibility of carbon sequestration by soil carbonate in hyperarid, arid, semiarid, or subhumid soils.

Monger, H.; Feng, Y.; Karnjanapiboonwang, A.

2013-12-01

51

Carbon dioxide sequestration by mineral carbonation  

Microsoft Academic Search

The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept behind mineral CO2 sequestration is the mimicking of natural weathering processes in which calcium or magnesium containing minerals

W. J. J. Huijgen; R. N. J. Comans

2007-01-01

52

Carbon-carbon grid for ion engines  

NASA Technical Reports Server (NTRS)

A method and apparatus of manufacturing a grid member for use in an ion discharge apparatus provides a woven carbon fiber in a matrix of carbon. The carbon fibers are orientated to provide a negatibe coefficient of thermal expansion for at least a portion of the grid member's operative range of use.

Garner, Charles E. (inventor)

1993-01-01

53

Carbon-carbon grid for ion engines  

NASA Technical Reports Server (NTRS)

A method and apparatus of manufacturing a grid member for use in an ion discharge apparatus provides a woven carbon fiber in a matrix of carbon. The carbon fibers are orientated to provide a negatibe coefficient of thermal expansion for at least a portion of the grid member's operative range of use.

Garner, Charles E. (inventor)

1995-01-01

54

Carbon monoxide  

PubMed Central

Carbon monoxide (CO), a by-product released during the degradation of heme by heme oxygenases (HOS EC 1.14.99.3) in animals, plays a major role as neurotransmitter, regulator of sinusoidal tone, inhibitor of platelet aggregation and suppressor of acute hypertensive response, and most of above effects are similar to or mediated by nitric oxide (NO), another signal molecule in both the animal and plant kingdoms. Previous result demonstrated that NO could act as a promoter of plant cell elongation, acting similarly to IAA, inducing morphogenetic responses leading to expansion in plant tissues. Recent observations revealed that CO is an inducer of cell expansion in wheat root segments, acting similarly to IAA and NO. Evidence also indicated that IAA could result in either the potent induction of HO-1 transcript or endogenous CO releasing in wheat root segments. Additionally, our results suggested that above CO signaling might be related to NO/cGMP, Ca2+ and even ROS-dependent pathways. In this addendum, combined with other previous results, we further proposed a possible hypothesis for CO signaling role in regulation of plant root development induced by auxin.

Xuan, Wei; Xu, Sheng; Yuan, Xingxing

2008-01-01

55

From carbon nanotubes to carbon atomic chains  

NASA Astrophysics Data System (ADS)

Carbyne is a linear allotrope of carbon. It is formed by a linear arrangement of carbon atoms with sp-hybridization. We present a reliable and reproducible experiment to obtain these carbon atomic chains using few-layer-graphene (FLG) sheets and a HRTEM. First the FLG sheets were synthesized from worm-like exfoliated graphite and then drop-casted on a lacey-carbon copper grid. Once in the TEM, two holes are opened near each other in a FLG sheet by focusing the electron beam into a small spot. Due to the radiation, the carbon atoms rearrange themselves between the two holes and form carbon fibers. The beam is concentrated on the carbon fibers in order excite the atoms and induce a tension until multi wall carbon nanotube (MWCNT) is formed. As the radiation continues the MWCNT breaks down until there is only a single wall carbon nanotube (SWCNT). Then, when the SWCNT breaks, an atomic carbon chain is formed, lasts for several seconds under the radiation and finally breaks. This demonstrates the stability of this carbon structure.

Casillas García, Gilberto; Zhang, Weijia; José-Yacamán, Miguel

2010-10-01

56

Biomedical Applications of Carbon Fibres.  

National Technical Information Service (NTIS)

The report covers (1) use of carbon fiber reinforced carbon (CFRC), generally for orthopedic application (joint replacement) (2) properties of carbon fiber; biocompatibility and mechanical factors (3) carbon fiber reinforced composites; CFRC (4) carbon fi...

G. W. Hastings

1984-01-01

57

Integrated Carbon Cycle Research Program  

NSF Publications Database

... aspects of the global carbon cycle in support of the U.S. Carbon Cycle Science Plan. Studies of the ... of carbon cycle research. The original U.S. Carbon Cycle Science Plan focus on carbon dioxide has ...

58

Acetylenic carbon allotrope  

DOEpatents

A fourth allotrope of carbon, an acetylenic carbon allotrope, is described. The acetylenic carbon allotropes of the present invention are more soluble than the other known carbon allotropes in many common organic solvents and possesses other desirable characteristics, e.g. high electron density, ability to burn cleanly, and electrical conductive properties. Many uses for this fourth allotrope are described herein.

Lagow, Richard J. (6204 Shadow Mountain Dr., Austin, TX 78731) [6204 Shadow Mountain Dr., Austin, TX 78731

1998-01-01

59

Acetylenic carbon allotrope  

DOEpatents

A fourth allotrope of carbon, an acetylenic carbon allotrope, is described. The acetylenic carbon allotropes of the present invention are more soluble than the other known carbon allotropes in many common organic solvents and possesses other desirable characteristics, e.g. high electron density, ability to burn cleanly, and electrical conductive properties. Many uses for this fourth allotrope are described herein.

Lagow, Richard J. (6204 Shadow Mountain Dr., Austin, TX 78731) [6204 Shadow Mountain Dr., Austin, TX 78731

1999-01-01

60

Composite carbon foam electrode  

Microsoft Academic Search

Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive

Steven T. Mayer; Richard W. Pekala; James L. Kaschmitter

1997-01-01

61

Composite carbon foam electrode  

Microsoft Academic Search

Carbon aerogels used as a binder for granulated materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive

S. T. Mayer; R. W. Pekala; J. L. Kaschmitter

1997-01-01

62

Acetylenic carbon allotrope  

DOEpatents

A fourth allotrope of carbon, an acetylenic carbon allotrope, is described. The acetylenic carbon allotropes of the present invention are more soluble than the other known carbon allotropes in many common organic solvents and possesses other desirable characteristics, e.g. high electron density, ability to burn cleanly, and electrical conductive properties. Many uses for this fourth allotrope are described herein. 17 figs.

Lagow, R.J.

1998-02-10

63

Pyrolyzed thin film carbon  

NASA Technical Reports Server (NTRS)

A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

2010-01-01

64

Carbon dioxide sequestration by direct mineral carbonation with carbonic acid  

Microsoft Academic Search

The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation,

William K. OConnor; David C. Dahlin; David N. Nilsen; Richard P. Walters; Paul C. Turner

2000-01-01

65

Carbon fibers modified with carbon nanotubes  

Microsoft Academic Search

Carbon nanotubes were used to modify a polyacrylonitrile (PAN) polymer solution before the manufacture of the carbon fiber\\u000a precursor. The modified PAN fibers were spun from a dimethylformamide solution containing a small amount of single-walled\\u000a carbon nanotubes. The fibers were characterized by thermogravimetry and optical and scanning electron microscopy. Structure,\\u000a morphology, and selected properties of the composite polymeric fibers and

Aneta Fraczek-Szczypta; Maciej Bogun; Stanislaw Blazewicz

2009-01-01

66

Laser Cladding on Carbon-Carbon Composites.  

National Technical Information Service (NTIS)

This report describes the results of experiments on laser cladding a variety of protective coatings onto carbon-carbon substrates as oxidation- protection coatings. The work was performed using a 12-kW flattop CO2 laser and a powder delivery system to inj...

J. J. Eric R. J. Hull

2002-01-01

67

Carbon molecules oscillating in carbon nanotube bundles  

Microsoft Academic Search

Fullerenes C60 and carbon nanotubes are of considerable interest to researchers from many scientific areas due to their unique electronic and mechanical properties. One application of these carbon nanostructures that has recently attracted much attention is the creation of an oscillator that operates in the gigahertz range frequency. A number of studies have found that the sliding of the inner-shell

Ngamta Thamwattana; Barry J. Cox; James M. Hill

2008-01-01

68

Method of making carbon-carbon composites  

DOEpatents

A process for making a carbon-carbon composite having a combination of high crystallinity, high strength, high modulus and high thermal and electrical conductivity. High-modulus/high-strength mesophase derived carbon fibers are woven into a suitable cloth. Layers of this easily graphitizable woven cloth are covered with petroleum or coal tar pitch and pressed at a temperature a few degrees above the softening point of the pitch to form a green laminated composite. The green composite is restrained in a suitable fixture and heated slowly to carbonize the pitch binder. The carbonized composite is then impregnated several times with pitch by covering the composite with hot pitch under pressure. The composites are given a heat treatment between each impregnation step to crack up the infiltrated carbon and allow additional pitch to enter the microstructure during the next impregnation cycle. The impregnated composites are then given a final heat treatment in the range 2500.degree. to 3000.degree. C. to fully graphitize the fibers and the matrix carbon. The composites are then infiltrated with pyrolytic carbon by chemical vapor deposition in the range 1000.degree. to 1300.degree. C. at a reduced pressure for approximately one hundred and fifty (150) hours.

Engle, Glen B. (16716 Martincoit Rd., Poway, CA 92064)

1991-01-01

69

Absorption of Carbon Dioxide on Carbonic Anhydrase Containing Substrates.  

National Technical Information Service (NTIS)

Carbonic anhydrase (CA), an enzyme catalyzing carbon dioxide hydration, was evaluated for its enhancement of carbon dioxide removal when it is present in granular materials with high water content during exposure to carbon dioxide in an aerating stream. A...

J. P. Allen

1968-01-01

70

Recent advances in carbon-carbon materials systems  

NASA Technical Reports Server (NTRS)

Carbon-carbon materials and new oxidation resistant coating developments are discussed. Potential areas of application are highlighted. A short bibliography of selected references is included that describe carbon-carbon materials and related technology in detail.

Rummler, D. R.

1982-01-01

71

Ion Deposited Carbon Coatings.  

National Technical Information Service (NTIS)

The overall objective of this program is to demonstrate a system capable of reproducibly coating polycarbonate plastic sheet with ion deposited transparent carbon. The carbon coatings are to be characterized on the plastic sheet for potential use as a dur...

S. Aisenberg M. Stein

1983-01-01

72

When carbon footprints hop  

NASA Astrophysics Data System (ADS)

Despite having achieved legally binding commitments on emissions reductions, many countries have increased their appetite for carbon-intensive products, making up the difference through international trade. Anna Petherick reports on the sticky task of regulating these invisible carbon flows.

Petherick, Anna

2012-07-01

73

Carbon nanotube nanoelectrode arrays  

DOEpatents

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)

2008-11-18

74

Interstellar carbon in meteorites  

NASA Technical Reports Server (NTRS)

The Murchison and Allende chondrites contain up to 5 parts per million carbon that is enriched in carbon-13 by up to +1100 per mil (the ratio of carbon-12 to carbon-13 is approximately 42, compared to 88 to 93 for terrestrial carbon). This 'heavy' carbon is associated with neon-22 and with anomalous krypton and xenon showing the signature of the s-process (neutron capture on a slow time scale). It apparently represents interstellar grains ejected from late-type stars. A second anomalous xenon component ('CCFXe') is associated with a distinctive, light carbon (depleted in carbon-13 by 38 per mil), which, however, falls within the terrestrial range and hence may be of either local or exotic origin.

Swart, P. K.; Grady, M. M.; Pillinger, C. T.; Lewis, R. S.; Anders, E.

1983-01-01

75

Potassium carbonate poisoning  

MedlinePLUS

Potassium carbonate is a white powder used to make soap, glass, and other items. This article discusses poisoning from swallowing or breathing in potassium carbonate. This is for information only and not ...

76

Trading forest carbon - OSU  

EPA Science Inventory

Issues associate with trading carbon sequestered in forests are discussed. Scientific uncertainties associated with carbon measurement are discussed with respect to proposed accounting procedures. Major issues include: (1) Establishing baselines. (2) Determining additivity from f...

77

Carbon Based Nanotechnology: Review  

NASA Technical Reports Server (NTRS)

This presentation reviews publicly available information related to carbon based nanotechnology. Topics covered include nanomechanics, carbon based electronics, nanodevice/materials applications, nanotube motors, nano-lithography and H2O storage in nanotubes.

Srivastava, Deepak; Saini, Subhash (Technical Monitor)

1999-01-01

78

Graphitization in Carbon MEMS and Carbon NEMS  

NASA Astrophysics Data System (ADS)

Carbon MEMS (CMEMS) and Carbon NEMS (CNEMS) are an emerging class of miniaturized devices. Due to the numerous advantages such as scalable manufacturing processes, inexpensive and readily available precursor polymer materials, tunable surface properties and biocompatibility, carbon has become a preferred material for a wide variety of future sensing applications. Single suspended carbon nanowires (CNWs) integrated on CMEMS structures fabricated by electrospinning of SU8 photoresist on photolithographially patterned SU8 followed by pyrolysis are utilized for understanding the graphitization process in micro and nano carbon materials. These monolithic CNW-CMEMS structures enable the fabrication of very high aspect ratio CNWs of predefined length. The CNWs thus fabricated display core---shell structures having a graphitic shell with a glassy carbon core. The electrical conductivity of these CNWs is increased by about 100% compared to glassy carbon as a result of enhanced graphitization. We explore various tunable fabrication and pyrolysis parameters to improve graphitization in the resulting CNWs. We also suggest gas-sensing application of the thus fabricated single suspended CNW-CMEMS devices by using the CNW as a nano-hotplate for local chemical vapor deposition. In this thesis we also report on results from an optimization study of SU8 photoresist derived carbon electrodes. These electrodes were applied to the simultaneous detection of traces of Cd(II) and Pb(II) through anodic stripping voltammetry and detection limits as low as 0.7 and 0.8 microgL-1 were achieved. To further improve upon the electrochemical behavior of the carbon electrodes we elucidate a modified pyrolysis technique featuring an ultra-fast temperature ramp for obtaining bubbled porous carbon from lithographically patterned SU8. We conclude this dissertation by suggesting the possible future works on enhancing graphitization as well as on electrochemical applications

Sharma, Swati

79

Carbon Cycle Roleplay  

NSDL National Science Digital Library

In this creative roleplay activity, learners will explore the various processes of the carbon cycle using movement and props to aid in comprehension. Learners will understand that carbon changes forms throughout the carbon cycle, and that carbon is continuously moving throughout all the cycles at the same time. This standards-based lesson, which is great for the classroom, camps, or afterschool programs, includes roleplay cards and ideas for props.

Sciences, California A.

2008-01-01

80

Understanding the Carbon Cycle  

NSDL National Science Digital Library

In this unit, students use Internet resources, slide presentations, and modeling to explain how understanding the carbon cycle helps scientists understand and prepare for global climate change, what might happen if sources of carbon produced more than sinks could remove, and what might happen if sinks absorbed more than sources produced. They should understand how the carbon cycle affects various life forms and the role that carbon plays in their lives. Procedures, a glossary, assessments, and scoring rubrics are provided.

81

The Contemporary Carbon Cycle  

Microsoft Academic Search

The global carbon cycle refers to the exchanges of carbon within and between four major reservoirs: the atmosphere, the oceans, land, and fossil fuels. Carbon may be transferred from one reservoir to another in seconds (e.g., the fixation of atmospheric CO2 into sugar through photosynthesis) or over millennia (e.g., the accumulation of fossil carbon (coal, oil, gas) through deposition and

R. A. Houghton

2003-01-01

82

An Infrared Method for Quantification of Carbonate in Carbonated Apatites  

Microsoft Academic Search

Carbonated apatites of known carbonate content were used to develop a method which uses infrared (IR) spectroscopy for quantitative estimation of carbonate. The ratio of the extinction of the IR carbonate band at about 1,415 cm––1 to the extinction of the phosphate band at about 575 cm––1 is linearly related to the carbonate content of the carbonated apatite. Mixtures of

J. D. B. Featherstone; S. Pearson; R. Z. LeGeros

1984-01-01

83

Carbon management and biodiversity  

Microsoft Academic Search

International efforts to mitigate human-caused changes in the Earth's climate are considering a system of incentives (debits and credits) that would encourage specific changes in land use that can help to reduce the atmospheric concentration of carbon dioxide. The two primary land-based activities that would help to minimize atmospheric carbon dioxide are carbon storage in the terrestrial biosphere and the

Michael A. Huston; Gregg Marland

2003-01-01

84

Intro to Carbon Sequestration  

ScienceCinema

NETL's Carbon Sequestration Program is helping to develop technologies to capture, purify, and store carbon dioxide (CO2) in order to reduce greenhouse gas emissions without adversely influencing energy use or hindering economic growth. Carbon sequestration technologies capture and store CO2 that would otherwise reside in the atmosphere for long periods of time.

None

2010-01-08

85

Carbonation of Cerium Oxychloride.  

National Technical Information Service (NTIS)

Cerous carbonates can be used in thermochemical cycles for H production if the resulting ceric oxides can be converted back into cerous carbonates. One way is to reduce and hydrolyze ceric oxide with HCl to produce CeOCl and then to carbonate it. The reac...

E. J. Peterson E. I. Onstott M. G. Bowman

1977-01-01

86

Intro to Carbon Sequestration  

SciTech Connect

NETL's Carbon Sequestration Program is helping to develop technologies to capture, purify, and store carbon dioxide (CO2) in order to reduce greenhouse gas emissions without adversely influencing energy use or hindering economic growth. Carbon sequestration technologies capture and store CO2 that would otherwise reside in the atmosphere for long periods of time.

2008-03-06

87

Carbon Goes To…  

ERIC Educational Resources Information Center

The purposes of this activity are to help middle school students understand the carbon cycle and realize how human activities affect the carbon cycle. This activity consists of two parts. The first part of the activity focuses on the carbon cycle, especially before the Industrial Revolution, while the second part of the activity focuses on how…

Savasci, Funda

2014-01-01

88

Aspects of carbon dioxide utilization  

Microsoft Academic Search

Carbon dioxide reacts with hydrogen, alcohols, acetals, epoxides, amines, carbon–carbon unsaturated compounds, etc. in supercritical carbon dioxide or in other solvents in the presence of metal compounds as catalysts. The products of these reactions are formic acid, formic acid esters, formamides, methanol, dimethyl carbonate, alkylene carbonates, carbamic acid esters, lactones, carboxylic acids, polycarbonate (bisphenol-based engineering polymer), aliphatic polycarbonates, etc. Especially,

Iwao Omae

2006-01-01

89

Carbon dioxide sequestration by direct mineral carbonation with carbonic acid  

SciTech Connect

The Albany Research Center (ARC) of the U.S. Dept. of Energy (DOE) has been conducting a series of mineral carbonation tests at its Albany, Oregon, facility over the past 2 years as part of a Mineral Carbonation Study Program within the DOE. Other participants in this Program include the Los Alamos National Laboratory, Arizona State University, Science Applications International Corporation, and the DOE National Energy Technology Laboratory. The ARC tests have focused on ex-situ mineral carbonation in an aqueous system. The process developed at ARC utilizes a slurry of water mixed with a magnesium silicate mineral, olivine [forsterite end member (Mg2SiO4)], or serpentine [Mg3Si2O5(OH)4]. This slurry is reacted with supercritical carbon dioxide (CO2) to produce magnesite (MgCO3). The CO2 is dissolved in water to form carbonic acid (H2CO3), which dissociates to H+ and HCO3 -. The H+ reacts with the mineral, liberating Mg2+ cations which react with the bicarbonate to form the solid carbonate. The process is designed to simulate the natural serpentinization reaction of ultramafic minerals, and for this reason, these results may also be applicable to in-situ geological sequestration regimes. Results of the baseline tests, conducted on ground products of the natural minerals, have been encouraging. Tests conducted at ambient temperature (22 C) and subcritical CO2 pressures (below 73 atm) resulted in very slow conversion to the carbonate. However, when elevated temperatures and pressures are utilized, coupled with continuous stirring of the slurry and gas dispersion within the water column, significant reaction occurs within much shorter reaction times. Extent of reaction, as measured by the stoichiometric conversion of the silicate mineral (olivine) to the carbonate, is roughly 90% within 24 hours, using distilled water, and a reaction temperature of 185?C and a partial pressure of CO2 (PCO2) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine and 84% conversion of olivine to the carbonate in 6 hours. The results from the current studies suggest that reaction kinetics can be improved by pretreatment of the mineral, catalysis of the reaction, or some combination of the two. Future tests are intended to examine a broader pressure/temperature regime, various pretreatment options, as well as other mineral groups.

O'Connor, William K.; Dahlin, David C.; Nilsen, David N.; Walters, Richard P.; Turner, Paul C.

2000-01-01

90

Carbon/Carbon for satellite applications  

NASA Astrophysics Data System (ADS)

Carbon/Carbon has many attributes that make it an attractive material for satellite applications. It is low in density, is dimensionally stable under a wide variety of conditions, has very low thermal expansion, is relatively low in cost, and is a mature technology. Moreover, the material is flexible enough to enable the designer to select such variables as fiber type, fabric architecture, fiber volume, and high temperature processing and thus custom tailor the physical and mechanical properties to his specific requirements. A wide range of properties are available - densities from 1.5 to 1.9 g/cm3, room temperature Coefficients of Thermal Expansion (CTE) from -0.3x10-6to -1.3x10-6/K, room temperature thermal conductivities from 7 to 210 W/m.K, and modulus from 60 to 190 GPa. A new type of structure developed by CNRS on the space instrument SODISM uses Carbon/Carbon.

Meftah, M.; Lee, S.; Irbah, A.; Ostergren, S.

2011-05-01

91

Carbon isotopes in mollusk shell carbonates  

Microsoft Academic Search

Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell\\u000a formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod\\u000a shell carbonates. Land snails construct their shells mainly from respired CO2, and shell ?13C reflects the local mix of C3 and C4 plants

Ted A. McConnaughey; David Paul Gillikin

2008-01-01

92

Mechanical behavior of carbon-carbon composites  

NASA Technical Reports Server (NTRS)

A general background, test plan, and some results of preliminary examinations of a carbon-carbon composite material are presented with emphasis on mechanical testing and inspection techniques. Experience with testing and evaluation was gained through tests of a low modulus carbon-carbon material, K-Karb C. The properties examined are the density - 1.55 g/cc; four point flexure strength in the warp - 137 MPa (19,800 psi) and the fill - 95.1 MPa (13,800 psi,) directions; and the warp interlaminar shear strength - 14.5 MPa (2100 psi). Radiographic evaluation revealed thickness variations and the thinner areas of the composite were scrapped. The ultrasonic C-scan showed attenuation variations, but these did not correspond to any of the physical and mechanical properties measured. Based on these initial tests and a survey of the literature, a plan has been devised to examine the effect of stress on the oxidation behavior, and the strength degradation of coated carbon-carbon composites. This plan will focus on static fatigue tests in the four point flexure mode in an elevated temperature, oxidizing environment.

Rozak, G. A.

1984-01-01

93

Carbon dioxide sensor  

DOEpatents

The present invention generally relates to carbon dioxide (CO.sub.2) sensors. In one embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor that incorporates lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3). In another embodiment, the present invention relates to a carbon dioxide (CO.sub.2) sensor has a reduced sensitivity to humidity due to a sensing electrode with a layered structure of lithium carbonate and barium carbonate. In still another embodiment, the present invention relates to a method of producing carbon dioxide (CO.sub.2) sensors having lithium phosphate (Li.sub.3PO.sub.4) as an electrolyte and sensing electrode comprising a combination of lithium carbonate (Li.sub.2CO.sub.3) and barium carbonate (BaCO.sub.3).

Dutta, Prabir K. (Worthington, OH); Lee, Inhee (Columbus, OH); Akbar, Sheikh A. (Hilliard, OH)

2011-11-15

94

The Growth and Characterization of Germanium-Carbon Alloy Thin Films and Solid Phase Equilibria for Metal-Silicon - Ternary Systems: Magnesium, Calcium, Strontium, Barium, Scandium, Yttrium, Lanthanum, Titanium, Zirconium and Hafnium  

Microsoft Academic Search

Thin films of pure germanium-carbon alloys (Ge _{rm x}C _{rm 1-x} with 0 <=q x <=q 1) have been grown on Si and Al_2O_3 substrates by pulsed laser ablation in a high vacuum chamber. The films were analyzed by x-ray 0-20 diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), conductivity measurements and optical absorption spectroscopy. The analyses of

Haojie Yuan

1992-01-01

95

Molten carbonate fuel cell separator  

DOEpatents

In a stacked array of molten carbonate fuel cells, a fuel cell separator is positioned between adjacent fuel cells to provide isolation as well as a conductive path therebetween. The center portion of the fuel cell separator includes a generally rectangular, flat, electrical conductor. Around the periphery of the flat portion of the separator are positioned a plurality of elongated resilient flanges which form a gas-tight seal around the edges of the fuel cell. With one elongated flange resiliently engaging a respective edge of the center portion of the separator, the sealing flanges, which are preferably comprised of a noncorrosive material such as an alloy of yttrium, iron, aluminum or chromium, form a tight-fitting wet seal for confining the corrosive elements of the fuel cell therein. This arrangement permits a good conductive material which may be highly subject to corrosion and dissolution to be used in combination with a corrosion-resistant material in the fuel cell separator of a molten carbonate fuel cell for improved fuel cell conductivity and a gas-tight wet seal.

Nickols, R.C.

1984-10-17

96

Plumbing carbon nanotubes.  

PubMed

Since their discovery, the possibility of connecting carbon nanotubes together like water pipes has been an intriguing prospect for these hollow nanostructures. The serial joining of carbon nanotubes in a controlled manner offers a promising approach for the bottom-up engineering of nanotube structures--from simply increasing their aspect ratio to making integrated carbon nanotube devices. To date, however, there have been few reports of the joining of two different carbon nanotubes. Here we demonstrate that a Joule heating process, and associated electro-migration effects, can be used to connect two carbon nanotubes that have the same (or similar) diameters. More generally, with the assistance of a tungsten metal particle, this technique can be used to seamlessly join any two carbon nanotubes--regardless of their diameters--to form new nanotube structures. PMID:18654444

Jin, Chuanhong; Suenaga, Kazu; Iijima, Sumio

2008-01-01

97

Mesoporous carbon materials  

DOEpatents

The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.

Dai, Sheng (Knoxville, TN); Wang, Xiqing (Oak Ridge, TN)

2012-02-14

98

Creating With Carbon  

NASA Technical Reports Server (NTRS)

A subsidiary of SI Diamond Technology, Inc., Applied Nanotech, of Austin, Texas, is creating a buzz among various technology firms and venture capital groups interested in the company s progressive research on carbon-related field emission devices, including carbon nanotubes, filaments of pure carbon less than one ten-thousandth the width of human hair. Since their discovery in 1991, carbon nanotubes have gained considerable attention due to their unique physical properties. For example, a single perfect carbon nanotube can range from 10 to 100 times stronger than steel, per unit weight. Recent studies also indicate that the nanotubes may be the best heat-conducting material in existence. These properties, combined with the ease of growing thin films or nanotubes by a variety of deposition techniques, make the carbon-based material one of the most desirable for cold field emission cathodes.

2003-01-01

99

Mesoporous carbon materials  

DOEpatents

The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.

Dai, Sheng; Wang, Xiqing

2013-08-20

100

Carbon Nanocomposite Based on Carbon Nanotubes and Ultrananocrystalline Diamond  

Microsoft Academic Search

Carbon-based nanostructured materials exhibit many interesting properties that are dictated by the many different bonding configurations available to carbon. Two typical examples are carbon nanotubes (CNTs) and ultrananocrystalline diamond (UNCD), with the former being sp2 bonded carbon and latter being sp3 bonded carbon. Recent advances in micro and nanofabrication techniques have made possible the development of microscale and perhaps even

Xingcheng Xiao; Jian Wang; Orlando Auciello; John A. Carlisle

2004-01-01

101

Carbon nanofibers and carbon nanotubes in regenerative medicine  

Microsoft Academic Search

Carbon nanotubes and carbon nanofibers have long been investigated for applications in composite structural materials, semiconductor devices, and sensors. With the recent well-documented ability to chemically modify nanofibrous carbon materials to improve their solubility and biocompatibility properties: a whole new class of bioactive carbon nanostructures has been created for biological applications. This review focuses on the latest applications of carbon

Phong A. Tran; Lijie Zhang; Thomas J. Webster

2009-01-01

102

Adsorption of Carbon Dioxide on Chemically Modified Carbon Adsorbents  

Microsoft Academic Search

Carbon adsorbents were chemically modified to have base sites on their surfaces, and the adsorption characteristics of carbon dioxide on them were investigated. Three kinds of carbon materials were used as support materials: two activated carbons and a carbon black. Base sites were introduced by impregnating the support materials with calcium acetate solution, followed by calcination at 700°C for 2

Hyun-K Song; Kun-Hing Lee

1998-01-01

103

Some Observations on Stress Graphitization in Carbon-Carbon Composites.  

National Technical Information Service (NTIS)

The in situ stress graphitization behavior of hard carbons in unidirectionally aligned carbon-carbon (C/C) composites was studied for three carbon fibers (PAN-based T-50, pitch-based PX7, and rayon-based WCA) and two carbon precursor resins (phenol-formal...

R. J. Zaldivar G. S. Rellick

1992-01-01

104

Why is Carbon Important?  

NSDL National Science Digital Library

Students explore the carbon cycle and the relationship between atmospheric carbon dioxide concentrations and temperature. Students create and compare graphs of carbon dioxide and temperature data from one local (Mauna Loa, Hawaii) meteorological station and one NASA global data set. These graphs, as well as a global vegetation map and an atmospheric wind circulation patterns diagram, are used as evidence to support the scientific claims they develop through their analysis and interpretation.

Center, Nasa G.

105

The Carbon Cycle  

NSDL National Science Digital Library

Since living things extract carbon from their nonliving environment, for life to continue carbon must be recycled. This site tells us that the cycle is not in balance and explores the possibilities of where the missing carbon might be found. The site also explains the greenhouse effect and global warming and also covers the other greenhouse gases such as methane and chlorofluorocarbons (CFCs). It also features diagrams, a graph, and links to other sites for more detailed information.

Kimball, John

106

USGS Carbon Cycle Research  

NSDL National Science Digital Library

This portal provides access to information on United States Geological Survey (USGS) research activities conducted in support of the U.S. Carbon Cycle Science Program (CCSP). This research includes carbon sequestration in sediments, landscape dynamics and vegetation change, fate of carbon in cold region forests, exchanges of greenhouse gases, water vapor, and heat at the Earth's surface, and other topics. Each topic heading features links to reports or program webpages.

107

Seeing the Carbon Cycle  

NSDL National Science Digital Library

The most important biochemical reactions for life in the ocean and on Earth are cellular respiration and photosynthesis. These two reactions play a central role in the carbon cycle. The ocean-based carbon cycle is highly relevant to today's students because of its key role in global warming. This experiment allows middle school students to observe the influence of the carbon cycle on algae growth, explore experimental design, collect data, and draw a conclusion.

Cramer, Catherine; Engle-Belknap, Cheryl A.; Repeta, Daniel; Welty, David J.; Frashure, Kim; Drouin, Pamela

2006-01-01

108

The carbon dioxide cycle  

USGS Publications Warehouse

The seasonal CO2 cycle on Mars refers to the exchange of carbon dioxide between dry ice in the seasonal polar caps and gaseous carbon dioxide in the atmosphere. This review focuses on breakthroughs in understanding the process involving seasonal carbon dioxide phase changes that have occurred as a result of observations by Mars Global Surveyor. ?? 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

James, P. B.; Hansen, G. B.; Titus, T. N.

2005-01-01

109

Temperature VS Carbon Dioxide  

NSDL National Science Digital Library

In this activity, students examine the relationship between carbon dioxide levels and global temperature change by studying a graph of these two variables. They will discover that by using data from ice cores, scientists can determine temperature and carbon dioxide levels in the air as far back as a hundred thousand years in the past. The students try to predict which variable is the independent one and then make a graph of temperature change and carbon dioxide levels. After making their graph, students describe the relationship between temperature and carbon dioxide levels in the atmosphere to determine if their predictions were correct.

110

Nanographene reinforced carbon/carbon composites  

NASA Astrophysics Data System (ADS)

Carbon/Carbon Composites (CCC) are made of carbon reinforcement in carbon matrix and have high thermal stability and fatigue resistance. CCC are used in nose cones, heat shields and disc brakes of aircrafts due to their exceptional mechanical properties at high temperature. The manufacturing process of CCC involves a carbonization stage in which unwanted elements, except carbon, are eliminated from the polymer precursor. Carbonization results in the formation of voids and cracks due to the thermal mismatch between the reinforcement and the matrix and expulsion of volatiles from the polymer matrix. Thermal cracks and voids decrease the density and mechanical properties of the manufactured CCC. In this work, Nanographene Platelets (NGP) were explored as nanofillers to fill the voids/cracks and reduce thermal shrinkage in CCC. They were first compared with Vapor Grown Carbon Nanofibers (VGCNF) by dispersion of different concentrations (0.5wt%, 1.5wt%, 3wt%) in resole-type phenolic resin and were characterized to explore their effect on rheology, heat of reaction and wetting behavior. The dispersions were then cured to form nanocomposites and were characterized for morphology, flexure and thermal properties. Finally, NGP were introduced into the carbon/carboncomposites in two stages, first by spraying in different concentrations (0.5wt%, 1.5wt%, 3wt%, 5wt %) during the prepreg formation and later during densification by directly mixing in the corresponding densification mix. The manufactured NGP reinforced CCC were characterized for microstructure, porosity, bulk density and mechanical properties (Flexure and ILSS) which were further cross-checked by non-destructive techniques (vibration and ultrasonic). In this study, it was further found that at low concentration (? 1.5 wt%) NGP were more effective in increasing the heat of reaction and in decreasing the viscosity of the phenolic resin. The decrease in viscosity led to better wetting properties of NGP / phenolic dispersions compared to VGCNF/phenolic dispersions. In nanocomposites, at low concentration (? 1.5 wt%), NGP were effective in increasing the flexure strength, char content and lowering the porosity and coefficient of thermal expansion of neat phenolic resin. At higher concentration (>1.5wt%), NGP had a tendency to agglomerate and lost their effectiveness. The behavior observed in nanocomposites continued in manufactured CCC. The highest Inter Laminar Shear Strength (ILSS), flexure strength/modulus, stiffness and density was observed at 1.5 wt% NGP. In CCC at concentrations > 1.5 wt%, the properties (ILSS, flexure, stiffness, density) decreased due to agglomeration but they were still higher compared to that of neat CCC (without NGP).

Bansal, Dhruv

111

The Growth and Characterization of Germanium-Carbon Alloy Thin Films and Solid Phase Equilibria for Metal-Silicon - Ternary Systems: Magnesium, Calcium, Strontium, Barium, Scandium, Yttrium, Lanthanum, Titanium, Zirconium and Hafnium  

NASA Astrophysics Data System (ADS)

Thin films of pure germanium-carbon alloys (Ge _{rm x}C _{rm 1-x} with 0 <=q x <=q 1) have been grown on Si and Al_2O_3 substrates by pulsed laser ablation in a high vacuum chamber. The films were analyzed by x-ray 0-20 diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), conductivity measurements and optical absorption spectroscopy. The analyses of these new materials showed that films of all compositions were amorphous, free of contamination and uniform in composition. By changing the film composition, the optical band gap of these semiconducting films was varied from 0.00 eV to 0.85 eV for x = 0.0 to 1.0 respectively. According to the AES results, the carbon atoms in the Ge-C alloy thin film samples have a bonding structure that is a mixture of sp^2 and sp^3 hybridizations. The presence of the sp^2 C is apparently what causes the bandgap of amorphous Ge-C alloys to decrease with increasing carbon concentration. The solidus portion of the ternary phase diagrams of the type M-Si-O, where M = Mg, Ca, Sr, Ba, Sc, Y, La, Ti, Zr and Hf have been derived at 298K and 1 atm oxygen partial pressure by investigating the bulk reactions possible in these systems. These phase diagrams, which have been determined by experiments and by calculations using thermodynamic data available, can be used to predict the occurrence of the reaction products or the stability of the phases present at the interfaces between different solid materials. Hence, they provide guides in designing thin film structures and in selecting candidate materials to form chemically stable interfaces. A research effort has been made on the investigation of the growth of diamond thin films from a carbon containing solid-CI_4, using laser ablation technique. The film grown by laser ablation from CI _4 is mainly composed of carbon with very small amount of oxygen and iodine as indicated by x-ray photoelectron spectroscopy data. The Auger electron spectroscopy result shows that the film grown contains a mixture of sp^2 and sp^3 hybridized carbon. By using x-ray powder diffraction and magnetic susceptibility measurements methods, we studied the chemical stability of candidate interlayer materials between YBa _2Cu_3O _7-delta and Si. The results show that CaF_2 reacts with YBCO while BaF_2 is chemically stable with YBCO. LaGaO_3 and Ca _2SiO_4 are chemically stable with Si and more investigations need to be made on the reactivity between Ca_2SiO _4 and YBCO.

Yuan, Haojie

1992-09-01

112

Sorption of carbon dioxide onto sodium carbonate  

SciTech Connect

Sodium carbonate was used as a sorbent to capture CO{sub 2} from a gaseous stream of carbon dioxide, nitrogen, and moisture. The breakthrough data of CO{sub 2} were measured in a fixed bed to observe the reaction kinetics of CO{sub 2}-carbonate reaction. Several models such as the shrinking-core model, the homogeneous model, and the deactivation model in the non-catalytic heterogeneous reaction systems were used to explain the kinetics of reaction among CO{sub 2}, Na{sub 2}CO{sub 3}, and moisture using analysis of the experimental breakthrough data. Good agreement of the deactivation model was obtained with the experimental breakthrough data. The sorption rate constant and the deactivation rate constant were evaluated by analysis of the experimental breakthrough data using a nonlinear least squares technique and described as Arrhenius form.

Sang-Wook Park; Deok-Ho Sung; Byoung-Sik Choi; Kwang-Joong Oh; Kil-Ho Moon [Pusan National University, Busan (Republic of Korea). Division of Chemical Engineering

2006-07-01

113

Method for Making a Carbon-Carbon Cylinder Block  

NASA Technical Reports Server (NTRS)

A method for making a lightweight cylinder block composed of carbon-carbon is disclosed. The use of carbon-carbon over conventional materials. such as cast iron or aluminum, reduces the weight of the cylinder block and improves thermal efficiency of the internal combustion reciprocating engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall clearance can be small, especially when the carbon-carbon cylinder block is used in conjunction with a carbon-carbon piston. Use of the carbon-carbon cylinder block has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance.

Ransone, Phillip O. (Inventor)

1997-01-01

114

Carbon/Carbon Panels Cooled By Heat Pipes  

NASA Technical Reports Server (NTRS)

Durable and reusable high-temperature carbon/carbon heat-pipe structure operates at temperatures above 3,000 degree F (1,649 degree C) in vacuum or inert environment and up to 2,800 degree F (1,537 degree C) in oxidizing environment. New concept combines high-temperature heat-pipe and carbon/carbon technologies to extend both thermal structural capabilities of refractory-metal heat pipes and maximum heat-flux capability of carbon/carbon structures. Uses refractory-metal heat pipes embedded within carbon/carbon structure. Walls of heat pipes thin and contain working fluid (lithium or sodium) of heat pipe. Carbon/carbon acts as primary load-carrying part of structure. Heat pipes help to eliminate local hotspots and associated thermal gradients and stresses and to reduce peak surface temperatures of carbon/carbon to levels within capability of oxidation-resisting system.

Camarda, Charles J.; Ransone, Philip O.

1989-01-01

115

Development of CVD/Pan Felt Carbon/Carbon Frusta.  

National Technical Information Service (NTIS)

The preparation and evaluation of a chemically vapor deposited carbon/carbonized polyacrylonitrile/carbon frustum are described. The thermal gradient infiltration technique yielded a matrix composed primarily of the desired rough laminar microstructure. C...

F. H. Braaten G. T. Noles M. L. Lieberman R. M. Curlee

1975-01-01

116

Carbon capture and storage  

Microsoft Academic Search

Carbon capture and storage (CCS) covers a broad range of technologies that are being developed to allow carbon dioxide (CO2) emissions from fossil fuel use at large point sources to be transported to safe geological storage, rather than being emitted to the atmosphere. Some key enabling contributions from technology development that could help to facilitate the widespread commercial deployment of

Jon Gibbins; Hannah Chalmers

2008-01-01

117

Lead carbonate scintillator materials  

DOEpatents

Improved radiation detectors containing lead carbonate or basic lead carbonate as the scintillator element are disclosed. Both of these scintillators have been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to other known scintillator materials. The radiation detectors disclosed are favorably suited for use in general purpose detection and in medical uses.

Derenzo, Stephen E. (Pinole, CA); Moses, William W. (Berkeley, CA)

1991-01-01

118

Carbon Dioxide Emission Estimates  

NSDL National Science Digital Library

The Carbon Dioxide Information Analysis Center of the Oak Ridge National Laboratory provides this new data on carbon dioxide emissions from fossil fuel burning, hydraulic cement production, and gas flaring in 1995. Data for one degree grid cells can be downloaded from the site in addition to code for analysis of the data.

119

Fly ash carbon passivation  

DOEpatents

A thermal method to passivate the carbon and/or other components in fly ash significantly decreases adsorption. The passivated carbon remains in the fly ash. Heating the fly ash to about 500 and 800 degrees C. under inert gas conditions sharply decreases the amount of surfactant adsorbed by the fly ash recovered after thermal treatment despite the fact that the carbon content remains in the fly ash. Using oxygen and inert gas mixtures, the present invention shows that a thermal treatment to about 500 degrees C. also sharply decreases the surfactant adsorption of the recovered fly ash even though most of the carbon remains intact. Also, thermal treatment to about 800 degrees C. under these same oxidative conditions shows a sharp decrease in surfactant adsorption of the recovered fly ash due to the fact that the carbon has been removed. This experiment simulates the various "carbon burnout" methods and is not a claim in this method. The present invention provides a thermal method of deactivating high carbon fly ash toward adsorption of AEAs while retaining the fly ash carbon. The fly ash can be used, for example, as a partial Portland cement replacement in air-entrained concrete, in conductive and other concretes, and for other applications.

La Count, Robert B; Baltrus, John P; Kern, Douglas G

2013-05-14

120

Carbon Dioxide Fountain  

ERIC Educational Resources Information Center

This article presents the development of a carbon dioxide fountain. The advantages of the carbon dioxide fountain are that it is odorless and uses consumer chemicals. This experiment also is a nice visual experiment that allows students to see evidence of a gaseous reagent being consumed when a pressure sensor is available. (Contains 3 figures.)…

Kang, Seong-Joo; Ryu, Eun-Hee

2007-01-01

121

Nanotailored Carbon Fibers.  

National Technical Information Service (NTIS)

Various spinning trials of polyacrylonitrile (PAN) and PAN/carbon nanotube (CNT) fibers were conducted using single- and bi-component spinning to obtain precursor fiber for carbonization. Materials parameters, such as homo- vs co-polymer, as well as diffe...

H. G. Chae

2012-01-01

122

Carbon Dioxide Removal  

NSDL National Science Digital Library

In this experiment using sprigs of Elodea, learners will observe a natural process that removes carbon dioxide (CO2) from Earth's atmosphere. This process is a part of the carbon cycle and results in temperature suitable for life. Note: this experiment requires that learners make observations an hour or the next day after they set up the materials.

History, American M.

2008-01-01

123

Carbon nanotube polymer composites  

Microsoft Academic Search

The state of research into carbon nanotube\\/polymer–matrix composites for mechanical reinforcement is critically reviewed with emphasis on recent advances in CNT composite toughness. Particular interest is also given to interfacial bonding of carbon nanotubes to polymer matrices as it applies to stress transfer from the matrix to the CNT. Potential topics of oncoming focus are highlighted.

R. Andrews; M. C. Weisenberger

2004-01-01

124

The carbon cycle revisited  

NASA Technical Reports Server (NTRS)

Discussions during the Global Change Institute indicated a need to present, in some detail and as accurately as possible, our present knowledge about the carbon cycle, the uncertainties in this knowledge, and the reasons for these uncertainties. We discuss basic issues of internal consistency within the carbon cycle, and end by summarizing the key unknowns.

Bolin, Bert; Fung, Inez

1992-01-01

125

Ingredients for Life: Carbon  

NSDL National Science Digital Library

Carbon is the basis of all organic molecules. It is also one of the most abundant elements in the universe. This video segment illustrates the special characteristics of carbon that make it an essential ingredient for life. The segment is one minute thirty-eight seconds in length. A background essay and list of discussion questions are also provided.

2011-07-22

126

Water in porous carbons  

Microsoft Academic Search

We present an overview of progress in understanding the behavior of water in porous carbons at the molecular level. We survey experimental investigations, semi-empirical approaches, and simulation studies. Experimental work faces a number of challenges: the determination of the distribution of carbon microcrystal sizes, the densities and species of surface groups, the topological nature of the connected pore structure, and

John K. Brennan; Teresa J. Bandosz; Kendall T. Thomson; Keith E. Gubbins

2001-01-01

127

Carbon Dioxide and Climate.  

ERIC Educational Resources Information Center

The amount of carbon dioxide in the atmosphere is increasing at a rate that could cause significant warming of the Earth's climate in the not too distant future. Oceanographers are studying the role of the ocean as a source of carbon dioxide and as a sink for the gas. (Author/BB)

Brewer, Peter G.

1978-01-01

128

Monitoring Global Ocean Carbon Inventories.  

National Technical Information Service (NTIS)

Contents: Foreword by OOSDP chairman; Preface by Author; Significance of a Changing Oceanic Carbon Inventory; The Case for Monitoring Ocean Carbon Inventories; Ocean Carbon Monitoring Approaches (Air-Sea Fluxes, CO(sub 2) Transport within the Ocean, Inven...

D. W. R. Wallace

1995-01-01

129

The Carbons. The Different Classes of Carbon, Preparation, Properties, Utilization les Carbones. Les Differentes Classes de Carbones, Preparation, Proprietes, Utilisation.  

National Technical Information Service (NTIS)

Starting from any material, solid, liquid or gaseous, containing among other elements, carbon, one can prepare a variety of products containing practically only carbon. These products are called carbons and can be subdivided into classes: diamond, graphit...

1977-01-01

130

Chapter 4: Geological Carbon Sequestration.  

National Technical Information Service (NTIS)

Carbon sequestration is the long term isolation of carbon dioxide from the atmosphere through physical, chemical, biological, or engineered processes. The largest potential reservoirs for storing carbon are the deep oceans and geological reservoirs in the...

J. Friedmann H. Herzog

2006-01-01

131

Atmospheric Carbon Dioxide and Carbon Reservoir Changes  

Microsoft Academic Search

The net release of CO2 from the biosphere to the atmosphere between 1850 and 1950 is estimated to amount to 1.2 × 109 tons of carbon per year. During this interval, changes in land use reduced the total terrestrial biomass by 7 percent. There has been a smaller reduction in biomass over the last few decades. In the middle 19th

Minze Stuiver

1978-01-01

132

Carbon observation: the Integrated Carbon Observing System  

NASA Astrophysics Data System (ADS)

A better knowledge of the carbon sinks' underlying processes, and their sustainability, is required to assess current mitigation efforts and to better predict the future ability of the carbon cycle to uptake anthropogenic emissions. To address these needs, carbon observations are required to better estimate the fluxes of carbon greenhouse gases to and from the atmosphere. ICOS is a recently-launched, world-class research infrastructure dedicated to the monitoring and improved understanding of carbon sources and sinks. It consists of complementary, harmonized networks of long-term ecosystem monitoring stations focusing on Europe and adjacent regions. The ICOS networks will comprise 40 operational atmospheric stations (measuring atmospheric composition in greenhouse gases and other core parameters), as many ecosystem stations (measuring fluxes from ecosystems) and about 10 oceanic measurement platforms. The operational status is expected in 2014. The networks will be coordinated through a set of central facilities: three Thematic centres respectively for atmospheric, ecosystem and ocean data and stations performance assessment, and a Central analytical lab. The mission of the thematic centres is to process, validate and distribute data to end-users. ICOS will also set up a Carbon portal dedicated to easy discovery of and access to data and elaborated products such as flux maps by end users. Through its European Commission funded Preparatory phase ICOS has demonstrated its capability to monitor greenhouse gases across Europe at 4 atmospheric sites and 4 ecosystem sites, working in near real time with the Atmospheric and Ecosystem Thematic Centres. At this occasion, the instrumental package, the experimental set up and protocols prepared for the standardized ICOS station are tested. ICOS measurements will allow the estimation of regional fluxes at a typical resolution of 50 km daily from the atmospheric network, with a precision of ~40 gC m-2 yr-1. The ecosystem network informs on the small scale variability of fluxes and its drivers. ICOS needs to be well connected and interoperable with other global and regional networks. When completed, ICOS will contribute to provide the essential long-term observations required to understand the present state and predict future behaviour of the global carbon cycle and greenhouse gases' emissions.

Paris, J.; Ciais, P.; Papale, D.; Rivier, L.; Consortium, I.

2012-12-01

133

Carbon dioxide adsorbent study  

NASA Technical Reports Server (NTRS)

A study was initiated on the feasibility of using the alkali metal carbonate - bi-carbonate solid-gas reaction to remove carbon dioxide from the atmosphere of an EVA life support system. The program successfully demonstrates that carbon dioxide concentrations could be maintained below 0.1 mole per cent using this chemistry. Further a practical method for distributing the carbonates in a coherent sheet form capable of repeated regeneration (50 cycles) at modest temperatures (423 K), without loss in activity was also demonstrated. Sufficiently high reaction rates were shown to be possible with the carbonate - bi-carbonate system such that EVA hardware could be readily designed. Experimental and design data were presented on the basis of which two practical units were designed. In addition to conventional thermally regenerative systems very compact units using ambient temperature cyclic vacuum regeneration may also be feasible. For a one man - 8 hour EVA unit regenerated thermally at the base ship a system volume of 14 liters is estimated.

Onischak, M.; Baker, B. S.

1973-01-01

134

Remarkable diversity of carbon–carbon bonds: structures and properties of fullerenes, carbon nanotubes, and graphene  

Microsoft Academic Search

Large scientific community has been passionate in understanding different carbon nanostructures for last two decades. In this\\u000a review, we present the general description of low-dimensional carbon allotropes such as fullerenes (0D), carbon nanotubes\\u000a (1D), and graphene (2D). These structures have unique diversity of carbon–carbon bonds. Structures and electronic properties\\u000a of fullerenes, small closed carbon cages, and giant fullerenes are illustrated.

T. C. Dinadayalane; Jerzy Leszczynski

2010-01-01

135

Carbon isotope techniques  

SciTech Connect

This book is a hands-on introduction to using carbon isotope tracers in experimental biology and ecology. It is a bench-top reference with protocols for the study of plants, animals, and soils. The {sup 11}C, {sup 12}C, {sup 13}C, and {sup 14}C carbon isotopes are considered and standard techniques are described by established authors. The compilation includes the following features: specific, well-established, user-oriented techniques; carbon cycles in plants, animals, soils, air, and water; isotopes in ecological research; examples and sample calculations.

Coleman, D.C. (ed.) (Univ. of Georgia, Athens (United States)); Fry, B. (ed.) (Marine Biological Lab., Woods Hole, MA (United States))

1991-01-01

136

Carbon-fiber technology  

NASA Technical Reports Server (NTRS)

The state of the art of PAN based carbon fiber manufacture and the science of fiber behavior is surveyed. A review is given of the stabilization by oxidation and the subsequent carbonization of fibers, of the apparent structure of fibers deduced from scanning electron microscopy, from X-ray scattering, and from similarities with soft carbons, and of the known relations between fiber properties and heat treatment temperature. A simplified model is invoked to explain the electrical properties of fibers and recent quantum chemical calculations on atomic clusters are used to elucidate some aspects of fiber conductivity. Some effects of intercalation and oxidative modification of finished fibers are summarized.

Hansen, C. F.; Parker, J. A.

1980-01-01

137

Trees and Carbon  

NSDL National Science Digital Library

The transport and transformation of substances in the environment are known collectively as biogeochemical cycles. These global cycles involve the circulation of elements and nutrients that sustain both the biological and physical aspects of the environment. As an example, this discussion centers around the carbon cycle and how carbon is sequestered in trees. Students will perform an activity that replicates a case study in which the biomass of trees in a 15-acre plot of forest was calculated to determine the amount of carbon sequestered per acre.

Pratte, John

138

Squeezing carbon nanotubes  

NASA Astrophysics Data System (ADS)

In this paper we briefly review the high pressure Raman studies on single and double walled carbon nanotubes focussing on the perssure dependence of the low frequency radial breathing vibrational modes. Previous work on single walled carbon nanotube bundles have shown that the normalized pressure-induced frequency shift, = (1/R) (dR/dP) D2, where R is the radial mode frequency and D is the nanotube diameter. We show here that the R-modes due to the inner tubes in double walled carbon nanotubes, have a very small, diameter independent value for , as predicted for the case of isolated tubes.

Venkateswaran, Uma D.

2004-11-01

139

Carbon Nanotubes in Neuroscience  

PubMed Central

Carbon nanotubes have electrical, mechanical and chemical properties that make them one of the most promising materials for applications in neuroscience. Single-walled and multi-walled carbon nanotubes have been increasingly used as scaffolds for neuronal growth and more recently for neural stem cell growth and differentiation. They are also used in interfaces with neurons, where they can detect neuronal electrical activity and also deliver electrical stimulation to these cells. The emerging picture is that carbon nanotubes do not have obvious adverse effects on mammalian health. Thus in the near future they could be used in brain–machine interfaces.

Malarkey, Erik B.

2010-01-01

140

Improving carbon fixation pathways.  

PubMed

A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing and enhancing photosynthetic reactions in a species independent manner. Furthermore, the elucidation of alternative carbon-fixation routes distinct from the Calvin cycle raises possibilities that novel pathways and organisms can be utilized to fix atmospheric carbon dioxide into useful materials. PMID:22647231

Ducat, Daniel C; Silver, Pamela A

2012-08-01

141

Preparing to capture carbon  

SciTech Connect

Carbon sequestration from large sources of fossil fuel combustion, particularly coal, is an essential component of any serious plan to avoid catastrophic impacts of human-induced climate change. Scientific and economic challenges still exist, but none are serious enough to suggest that carbon capture and storage will not work at the scale required to offset trillions of tons of carbon dioxide emissions over the next century. The challenge is whether the technology will be ready when society decides that it is time to get going.

Schrag, D.P. [Harvard University, Cambridge, MA (United States)

2007-02-09

142

Preparing to capture carbon.  

PubMed

Carbon sequestration from large sources of fossil fuel combustion, particularly coal, is an essential component of any serious plan to avoid catastrophic impacts of human-induced climate change. Scientific and economic challenges still exist, but none are serious enough to suggest that carbon capture and storage will not work at the scale required to offset trillions of tons of carbon dioxide emissions over the next century. The challenge is whether the technology will be ready when society decides that it is time to get going. PMID:17289991

Schrag, Daniel P

2007-02-01

143

Carbon footprint calculator  

NSDL National Science Digital Library

This site is produced by British Petroleum and provides a simple, interactive guide to estimate your annual household carbon emissions. The calculator asks questions about the features of your residence, car travel, air travel and recycling habits. As each question is answered, a graph displays the carbon emissions so you can see the effects of each of the options presented. This tool is intended as an approximate guide only, but is useful for stimulating an awareness of the approximate amount of carbon dioxide emitted by everyday tasks.

Petroleum, British

144

Improving Carbon Fixation Pathways  

PubMed Central

A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing and enhancing photosynthetic reactions in a species independent manner. Furthermore, the elucidation of alternative carbon-fixation routes distinct from the Calvin cycle raises possibilities that alternative pathways and organisms can be utilized to fix atmospheric carbon dioxide into useful materials.

Ducat, Daniel C.

2012-01-01

145

Carbon dioxide sequestration in cement kiln dust through mineral carbonation  

Microsoft Academic Search

Carbon sequestration through the formation of carbonates is a potential means to reduce CO emissions. Alkaline industrial solid wastes typically have high mass fractions of reactive oxides that may not require preprocessing, making them an attractive source material for mineral carbonation. The degree of mineral carbonation achievable in cement kiln dust (CKD) under ambient temperatures and pressures was examined through

Deborah N. Huntzinger; John S. Gierke; S. Komar Kawatra; Timothy C. Eisele; Lawrence L. Sutter

2009-01-01

146

Low-carbon Economy and Low-carbon Food  

Microsoft Academic Search

This article has analyzed the influence of low-carbon (LC) economy on our country economy, particularly described on the concept of low-carbon food and carbon emissions in Chinese food currently, and explored the importance of the development low carbon food systematically.

Yang Xiaowei; Jia Xing

2011-01-01

147

The currencies of carbon: carbon money and its social meaning  

Microsoft Academic Search

Following the rapid development of carbon markets, little attention has been devoted to what precisely is being traded. Some authors have speculated that carbon can be considered as a form of money (Button; House and Victor). Not only is making money from carbon possible via several market devices but this process has also enabled the construction of carbon as a

Philippe Descheneau

2012-01-01

148

Pistons and Cylinders Made of Carbon-Carbon Composite Materials  

NASA Technical Reports Server (NTRS)

An improved reciprocating internal combustion engine has a plurality of engine pistons, which are fabricated from carbon---carbon composite materials, in operative association with an engine cylinder block, or an engine cylinder tube, or an engine cylinder jug, all of which are also fabricated from carbon-carbon composite materials.

Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor); Schwind, Francis A. (Inventor)

2000-01-01

149

Pistons and Cylinders Made of Carbon-Carbon Composite Materials  

NASA Technical Reports Server (NTRS)

An improved reciprocating internal combustion engine has a plurality of engine pistons, which are fabricated from carbon-carbon composite materials, in operative association with an engine cylinder block, or an engine cylinder tube, or an engine cylinder jug, all of which are also fabricated from carbon-carbon composite materials.

Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor); Schwind, Francis A. (Inventor)

2000-01-01

150

Carbon calabashes in a shock-produced carbon melt  

NASA Astrophysics Data System (ADS)

Carbon calabashes similar to those reported during decomposition of CH 4 between 900 and 1050 °C also formed after thermal decomposition of dolomite, CaMg(CO 3) 2 in a low-angle impact experiment that produced a carbon melt and complex gas phase between 2700 and 3700 °C. The interrelationships among various carbon forms in this experiment support that the calabashes are quenched carbon-melt bubbles at high gas to liquid ratios. Carbyne forms of carbon that crystallized within the quenched-liquid shell of the bubbles did not require a spiral growth mechanism. Carbon calabashes are an oddity but not a new form of elemental carbon.

Rietmeijer, Frans J. M.; Schultz, Peter H.; Bunch, Theodore E.

2003-06-01

151

Porous carbons prepared by direct carbonization of MOFs for supercapacitors  

NASA Astrophysics Data System (ADS)

Three porous carbons were prepared by direct carbonization of HKUST-1, MOF-5 and Al-PCP without additional carbon precursors. The carbon samples obtained by carbonization at 1073 K were characterized by XRD, TEM and N2 physisorption techniques followed by testing for electrochemical performance. The BET surface areas of the three carbons were in the range of 50-1103 m2/g. As electrode materials for supercapacitor, the MOF-5 and Al-PCP derived carbons displayed the ideal capacitor behavior, whereas the HKUST-1 derived carbon showed poor capacitive behavior at various sweep rates and current densities. Among those carbon samples, Al-PCP derived carbons exhibited highest specific capacitance (232.8 F/g) in 30% KOH solution at the current density of 100 mA/g.

Yan, Xinlong; Li, Xuejin; Yan, Zifeng; Komarneni, Sridhar

2014-07-01

152

Amazon River Cycles Carbon Faster than Thought  

NSF Publications Database

... 05-126Amazon River Cycles Carbon Faster than Thought Carbon is Returned to Atmosphere in Five Short ... gas carbon dioxide far faster - than anyone realized. Most of the carbon being exhaled as carbon ...

153

Carbon Monoxide Information Center  

MedlinePLUS Videos and Cool Tools

... Space Saving Sleep Solutions More CO Blogs Research & Statistics Non-Fire Carbon Monoxide Deaths Associated with the ... Driven Tools, 1999-2011 View All CO Research & Statistics Reports Inside CPSC: Recalls Safety Education Regulations, Laws & ...

154

Beyond forest carbon  

NASA Astrophysics Data System (ADS)

The preservation of forests, both on land and in mangrove swamps, has received much attention in the move to protect biological carbon stores. Less conspicuous communities of organisms deserve some scrutiny, too.

2012-07-01

155

Carbon Dioxide Monitoring.  

National Technical Information Service (NTIS)

The collection of luminescent microorganisms are maintained under cultivation to provide suitable biosensors for the testing program for carbon dioxide. The basic bioluminescent agar medium is currently being used for growth of the cultures. Tests of lumi...

P. S. Biernacki J. J. Kalvinskas

1973-01-01

156

Carbon monoxide intoxication  

SciTech Connect

Carbon monoxide poisoning usually results from inhalation of exhaust fumes from motor vehicles, smoke from fires or fumes from faulty heating systems. Carbon monoxide has a high affinity for hemoglobin, with which it forms carboxyhemoglobin. The resulting decrease in both oxygen-carrying capacity and oxygen release can lead to end-organ hypoxia. The clinical presentation is nonspecific. Headache, dizziness, fatigue and nausea are common in mild to moderate carbon monoxide poisoning. In more severe cases, tachycardia, tachypnea and central nervous system depression occur. When carbon monoxide intoxication is suspected, empiric treatment with 100 percent oxygen should be initiated immediately. The diagnosis is confirmed by documenting an elevated carboxyhemoglobin level. Hyperbaric oxygen therapy is recommended in patients with neurologic dysfunction, cardiac dysfunction or a history of unconsciousness. 26 refs.

Kales, S.N. (Cambridge Hospital, MA (United States))

1993-11-01

157

Ultrahigh Carbon Steel.  

National Technical Information Service (NTIS)

Recent studies and results on ultrahigh carbon (UHC) steels would suggest that major development efforts on these steels are timely and that programs to evaluate prototype structural components should be initiated. These recent results include: the develo...

O. D. Sherby T. Oyama D. W. Kum B. Walser J. Wadsworth

1984-01-01

158

Carbon monoxide poisoning  

MedlinePLUS

... Portable propane heaters Stoves (indoor and camp stoves) Water heater that use natural gas Note: This list may ... gas-burning appliances (such as a furnace or water heater). Many carbon monoxide poisonings occur in the winter ...

159

Carbon Cycle Research Plan.  

National Technical Information Service (NTIS)

The principal objective of the carbon cycle research plan is to develop the ability to estimate change in atmospheric CO sub 2 concentration expected to accompany additional combustion of fossil fuels. Related objectives are to understand how other pertur...

R. C. Dahlman

1984-01-01

160

Variability of carbon stars  

NASA Astrophysics Data System (ADS)

The results of photographic monitoring of carbon stars situated in several regions near the galactic equator, carried out with the Schmidt telescope, are reported. Almost all stars with light range in red passband (0.63 micron) exceeding one magnitude turned out to be long-period variables. About 10 percent of all carbon stars have light range in V passband larger than two magnitudes. In most cases, variations of long-period carbon stars can be regarded as a sum of two components: periodical and secondary. The cycle length of the secondary component is between 2 to 10 cycles of the periodic component. Carbon stars with thick circumstellar dust shells have extremely long (about 600 days) periods and a steep ascending branch of light curve. In the blue-violet radiation of the object CIT 6 = RW LMi, the periodic component of variations is absent, although the light range of the secondary component and short time fluctuations are the largest.

Alksnis, A.

161

Carbon dioxide (reduction).  

National Technical Information Service (NTIS)

The twin problems of global warming, caused by an increase in atmospheric carbon dioxide (CO2) concentrations, and limited fossil fuel resources have stimulated research in the utilization of CO2. These problems would be partially alleviated by the develo...

A. Fujita

2000-01-01

162

Estimating carbon monoxide exposure  

NASA Technical Reports Server (NTRS)

Method predicts effects of carbon monoxide on astronauts confined in spacecraft cabin atmospheres. Information on need for low toxicity level also applies to confined spaces. Benefits are applicable to industry and public health.

Edgerley, R. H.

1971-01-01

163

Carbon Monoxide (CO)  

MedlinePLUS

... CO are expected for short periods of time. ALERT: Put generators outside. Never use a generator inside ... Security, U.S. Fire Administration's Portable Generator Hazards page ALERT!! Preventing Carbon Monoxide Poisoning from Small Gasoline-Powered ...

164

Inert Carbon Free Radicals.  

National Technical Information Service (NTIS)

The first inert carbon free radicals, completely dissociated and with both chemical and thermal stability, are described. These compounds belong to the perchlorocarbon class and are exemplified by perchlorotriphenylmethyl, perchlorodiphenylmethyl, and rel...

M. Ballester

1968-01-01

165

Carbon sequestration in soils  

SciTech Connect

The purpose of this article is to examine (a) the magnitude of the potential for carbon sequestration in the soil as a means of reducing carbon dioxide (CO{sub 2}) in the atmosphere, (b) some of the measures that might be used to achieve this potential, (c) the methods available for estimating carbon sequestration on a farm or regional level, (d) what is needed to achieve international consensus, and (e) additional information needs. This article is not presented as a definitive document but rather as an overview of where scientific opinion converges and where more work is needed. In addition, it aims to provoke discussion of the measures that can increase soil carbon sequestration and the policies that might be used to implement those measures.

Bruce, J.P. [Soil and Water Conservation Society, Ottawa, Ontario (Canada); Frome, M. [Soil and Water Conservation Society, Washington, DC (United States); Haites, E. [Margaree Consultants, Toronto, Ontario (Canada); Janzen, H. [Agriculture and Agri-Food Canada, Lethbridge, Alberta (Canada); Lal, R. [Ohio State Univ., Columbus, OH (United States). School of Natural Resources; Paustian, K. [Colorado State Univ., Fort Collins, CO (United States). Natural Resource Ecology Lab.

1999-01-01

166

Activated carbon aerogels  

SciTech Connect

Activated carbon aerogels were obtained from the CO{sub 2} activation of the carbon aerogels. The adsorption isotherms of nitrogen on activated carbon aerogels at 77 K were measured and analyzed by the high-resolution {alpha}{sub s} plot to evaluate their porosities. The {alpha}{sub s} plot showed an upward deviation from linearity below {alpha}{sub s} = 0.5, suggesting that the presence of micropores becomes more predominant with the extent of the activation. Activation increased noticeably the pore volume and the surface area (the maximum value: 2600 m{sup 2}.g{sup -1}) without change of the basic network structure of primary particles. Activated carbon aerogels had a bimodal pore size distribution of uniform micropores and mesopores. 16 refs., 2 figs., 1 tab.

Hanzawa, Y.; Kaneko, K. [Chiba Univ. (Japan)] [Chiba Univ. (Japan); Pekala, R.W. [Lawrence Livermore National Lab., CA (United States)] [Lawrence Livermore National Lab., CA (United States); Dresselhaus, M.S. [Massachusetts Inst. of Technology, Cambridge, MA (United States)] [Massachusetts Inst. of Technology, Cambridge, MA (United States)

1996-12-25

167

Carbon Fiber Structure.  

National Technical Information Service (NTIS)

The structure of Polyacrylonitrile (PAN) and Cellulose (Rayon)-based carbon fibers in cross-section was investigated using various microscopic techniques. Commercial PAN fibers were found to be circumferentially oriented on the outside and radially orient...

J. V. Larsen T. G. Smith

1971-01-01

168

Carbon Nanotube Filter.  

National Technical Information Service (NTIS)

Monolithic, macroscopic, nanoporous nanotube filters are fabricated having radially aligned carbon nanotube walls. The freestanding filters have diameters and lengths up to several centimeters. A single-step filtering process was demonstrated in two impor...

A. Srivastava O. N. Srivastava P. M. Ajayan R. Vajtal S. Talapatra

2005-01-01

169

Carbon Isotope Ratios in Belowground Carbon Cycle Processes  

Microsoft Academic Search

Abstract Analyses of carbon isotope ratios (?,C values of CO2effluxing from soils, but asof,yet a global,database,is lacking,with which,to test this prediction. Such a global,database,would be a useful input for global carbon cycle models,which,rely on ?values,to constrain source and sink relations. Keywords: global change, ecosystem processes, soil organic carbon, carbon isotope ratio, carbon cycle,

James R. Ehleringer; Nina Buchmann; Lawrence B. Flanagan

2000-01-01

170

Lowstand carbonates, highstand sandstones?  

Microsoft Academic Search

The sedimentary facies, sediment dynamics and sequence architecture of modern high-energy shelves in the mid and high latitudes are largely governed by wave abrasion processes. Cool-water carbonates may form there, if the influx and\\/or net accretion of siliciclastics is kept at a minimum. Little dilution of the carbonate produced in situ is generally promoted by a wide “epicontinental” shelf, subdued

T. C Brachert; M. H Forst; J. J Pais; P Legoinha; J. J. G Reijmer

2003-01-01

171

Forms of Carbon  

NSDL National Science Digital Library

In this activity, educators can demonstrate how the nanoscale arrangement of atoms dramatically impacts a materialâs macroscale behavior. Learners investigate the structure and properties of four different forms of carbon. During the program, learners interact with models of four different forms of carbon. Learners also observe the conductivity of graphite (using a simple circuit and an everyday pencil) and the hardness of diamond (using a diamond scribe to cut glass).

Network, Nanoscale I.

2014-06-10

172

Joining carbon nanotubes.  

PubMed

To fully exploit the exceptional electronic and mechanical properties of carbon nanotubes in real-world applications, it is desirable to create carbon nanotube networks in which separate, multiple nanotubes are joined so that as many as possible of the properties of single nanotubes are conserved. In this review we summarize the progress made towards this goal, covering techniques including electron and ion beam irradiation, Joule heating and spark plasma sintering. PMID:21952820

Roberts, G Seth; Singjai, Pisith

2011-11-01

173

Lead carbonate scintillator materials  

DOEpatents

Improved radiation detectors containing lead carbonate or basic lead carbonate as the scintillator element are disclosed. Both of these scintillators have been found to provide a balance of good stopping power, high light yield and short decay constant that is superior to other known scintillator materials. The radiation detectors disclosed are favorably suited for use in general purpose detection and in medical uses. 3 figures.

Derenzo, S.E.; Moses, W.W.

1991-05-14

174

Amorphous Hydrogenated Carbon Nanofilm  

Microsoft Academic Search

Amorphous hydrogenated carbon (a-C:H) nanofilm is a metastable form of amorphous carbon with significant sp3 bonding. a-C:H\\u000a is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This chapter will describe\\u000a the deposition methods, deposition mechanisms, characterization methods, electronic structure, gap states, defects, doping,\\u000a luminescence, field emission, mechanical properties, and some applications of a-C:H. The films have

Dechun Ba; Zeng Lin

175

Functionalization of Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

These project will explore the functionalization of carbon nanotubes via the formation of molecular complexes with perylene diimide based systems. It is anticipated that these complexes would be soluble in organic solvent and enable the homogenous dispersion of carbon nanotubes in polymer films. Molecular complexes will be prepared and characterized using standard spectroscopic and thermal analytical techniques. Polymer films will be prepared with these complexes and their properties (electrical and thermal conductivity, mechanical properties, stability) evaluated.

Webber, Stephen E.

2003-01-01

176

Carbon nanotubes paste electrode  

Microsoft Academic Search

The performance of carbon nanotubes paste electrodes (CNTPE) prepared by dispersion of multi-wall carbon nanotubes (MWNT) within mineral oil is described. The resulting electrode shows an excellent electrocatalytic activity toward ascorbic acid, uric acid, dopamine, 3,4-dihydroxyphenylacetic acid (dopac) and hydrogen peroxide. These properties permit an important decrease in the overvoltage for the oxidation of ascorbic acid (230 mV), uric acid

Mar??a D Rubianes; Gustavo A Rivas

2003-01-01

177

Carbon nanotube field emitter.  

PubMed

Recently, carbon nanotubes (CNTs), possessing excellent properties as field emitters, are attracting considerable attention as electron emitters of a cold cathode. In this review article, field emission phenomena of carbon nanotubes with various morphologies and surfaces (clean surface or adsorbed molecules on it) revealed by field emission microscopy are first described. Then, the main subject of this article, application of CNTs as electron sources in display devices is reviewed. Other electric devices utilizing CNT-field emitters are also presented. PMID:12908229

Saito, Yahachi

2003-01-01

178

Method for synthesizing carbon nanotubes  

DOEpatents

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

2012-09-04

179

Carbon Nanotubes: Synthesis and Characterization  

Microsoft Academic Search

Carbon can form various types of structurally different frameworks due to the ability of the carbon atoms to form different species of valence bonds. The extremely organized coagulation process of carbon molecules resulting in the formation of the perfectly symmetric fullerene molecule despite the chaotic environment of the carbon arc is truly fascinating. Although many formation theories for the buckyball

Yamini Yadav; Vindhya Kunduru; Shalini Prasad

180

Molecular Structure of Carbonic acid  

NSDL National Science Digital Library

The hypothetical acid formed with carbon dioxide and water; it is only in the H2CO3 form when in solution. This acid is found in everyday products, the most prominent of which include carbonated beverages. The conversion of carbonic acid into water and carbon dioxide in sodas is the reason the beverage looses the bubbling.

2002-09-10

181

Carbon Embedded in China's Trade  

Microsoft Academic Search

A large fraction of China's greenhouse gas emissions are incurred in order to satisfy final demand of consumers in other countries; in effect, carbon emissions are embedded in China's exports. This paper explores the economic context and policy implications of carbon embedded in China's trade. China is a net exporter of embedded carbon because its entire economy is carbon-intensive; if

Frank Ackerman

182

Nano-carbons as theranostics.  

PubMed

Nano-carbons, including fullerenes, carbon nanoparticles, carbon nanotubes, graphene, and nano-diamonds, are an important class of nanostructures attracting tremendous interests in the past two decades. In this special issue, seven review articles and research reports are collected, to summarize and present the latest progress in the exploration of various nano-carbons for theranostic applications. PMID:22448193

Liu, Zhuang; Liang, Xing-Jie

2012-01-01

183

Closing the fuel carbon cycle  

Microsoft Academic Search

The global carbon cycle involves constant exchange of carbon atoms between the atmosphere, land, and ocean through biological, chemical and geological processes. This natural cycle of uptake and release of carbon is roughly in balance. However, the global industrialization of the past two centuries has released carbon to the atmosphere, mostly in the form of COâ that had been locked

Powicki

2007-01-01

184

Carbon management and biodiversity.  

PubMed

International efforts to mitigate human-caused changes in the Earth's climate are considering a system of incentives (debits and credits) that would encourage specific changes in land use that can help to reduce the atmospheric concentration of carbon dioxide. The two primary land-based activities that would help to minimize atmospheric carbon dioxide are carbon storage in the terrestrial biosphere and the efficient substitution of biomass fuels and bio-based products for fossil fuels and energy-intensive products. These two activities have very different land requirements and different implications for the preservation of biodiversity and the maintenance of other ecosystem services. Carbon sequestration in living forests can be pursued on lands with low productivity, i.e. on lands that are least suitable for agriculture or intensive forestry, and are compatible with the preservation of biodiversity over large areas. In contrast, intensive harvest-and-use systems for biomass fuels and products generally need more productive land to be economically viable. Intensive harvest-and-use systems may compete with agriculture or they may shift intensive land uses onto the less productive lands that currently harbor most of the Earth's biodiversity. Win-win solutions for carbon dioxide control and biodiversity are possible, but careful evaluation and planning are needed to avoid practices that reduce biodiversity with little net decrease in atmospheric carbon dioxide. Planning is more complex on a politically subdivided Earth where issues of local interest, national sovereignty, and equity come into play. PMID:12659806

Huston, Michael A; Marland, Gregg

2003-01-01

185

Molten carbonate fuel cell cathode with mixed oxide coating  

DOEpatents

A molten carbonate fuel cell cathode having a cathode body and a coating of a mixed oxygen ion conductor materials. The mixed oxygen ion conductor materials are formed from ceria or doped ceria, such as gadolinium doped ceria or yttrium doped ceria. The coating is deposited on the cathode body using a sol-gel process, which utilizes as precursors organometallic compounds, organic and inorganic salts, hydroxides or alkoxides and which uses as the solvent water, organic solvent or a mixture of same.

Hilmi, Abdelkader; Yuh, Chao-Yi

2013-05-07

186

Method of manufacturing carbon nanotubes  

NASA Technical Reports Server (NTRS)

A process for manufacturing carbon nanotubes, including a step of inducing electrical current through a carbon anode and a carbon cathode under conditions effective to produce the carbon nanotubes, wherein the carbon cathode is larger than the carbon anode. Preferably, a welder is used to induce the electrical current via an arc welding process. Preferably, an exhaust hood is placed on the anode, and the process does not require a closed or pressurized chamber. The process provides high-quality, single-walled carbon nanotubes, while eliminating the need for a metal catalyst.

Benavides, Jeanette M. (Inventor); Leidecker, Henning W. (Inventor); Frazier, Jeffrey (Inventor)

2004-01-01

187

Carbon foam/hydroxyapatite coating for carbon/carbon composites: Microstructure and biocompatibility  

NASA Astrophysics Data System (ADS)

To improve the surface biocompatibility of carbon/carbon composites, a carbon foam/hydroxyapatite coating was applied using a combination method of slurry procedure and ultrasound-assisted electrochemical deposition procedure. The morphology, microstructure and chemical composition of the coating were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray diffraction. The biocompatibility of the carbon foam/hydroxyapatite coating was investigated by osteoblast-like MG63 cell culture tests. The results showed that the carbon foam could provide a large number of pores on the surface of carbon/carbon composites. The hydroxyapatite crystals could infiltrate into the pores and form the carbon foam/hydroxyapatite coating. The coating covered the carbon/carbon composites fully and uniformly with slice morphology. The cell response tests showed that the MG63 cells on carbon foam/hydroxyapatite coating had a better cell adhesion and cell proliferation than those on uncoated carbon/carbon composites. The carbon foam/hydroxyapatite coatings were cytocompatible and were beneficial to improve the biocompatibility. The approach presented here may be exploited for fabrication of carbon/carbon composite implant surfaces.

Zhang, Leilei; Li, Hejun; Li, Kezhi; Zhang, Shouyang; Lu, Jinhua; Li, Wei; Cao, Sheng; Wang, Bin

2013-12-01

188

Carbon nanotube core graphitic shell hybrid fibers.  

PubMed

A carbon nanotube yarn core graphitic shell hybrid fiber was fabricated via facile heat treatment of epoxy-based negative photoresist (SU-8) on carbon nanotube yarn. The effective encapsulation of carbon nanotube yarn in carbon fiber and a glassy carbon outer shell determines their physical properties. The higher electrical conductivity (than carbon fiber) of the carbon nanotube yarn overcomes the drawbacks of carbon fiber/glassy carbon, and the better properties (than carbon nanotubes) of the carbon fiber/glassy carbon make up for the lower thermal and mechanical properties of the carbon nanotube yarn via synergistic hybridization without any chemical doping and additional processes. PMID:24224730

Hahm, Myung Gwan; Lee, Jae-Hwang; Hart, Amelia H C; Song, Sung Moo; Nam, Jaewook; Jung, Hyun Young; Hashim, Daniel Paul; Li, Bo; Narayanan, Tharangattu N; Park, Chi-Dong; Zhao, Yao; Vajtai, Robert; Kim, Yoong Ahm; Hayashi, Takuya; Ku, Bon-Cheol; Endo, Morinobu; Barrera, Enrique; Jung, Yung Joon; Thomas, Edwin L; Ajayan, Pulickel M

2013-12-23

189

Measurement of carbon capture efficiency and stored carbon leakage  

DOEpatents

Data representative of a measured carbon dioxide (CO.sub.2) concentration and of a measured oxygen (O.sub.2) concentration at a measurement location can be used to determine whether the measured carbon dioxide concentration at the measurement location is elevated relative to a baseline carbon dioxide concentration due to escape of carbon dioxide from a source associated with a carbon capture and storage process. Optionally, the data can be used to quantify a carbon dioxide concentration increase at the first location that is attributable to escape of carbon dioxide from the source and to calculate a rate of escape of carbon dioxide from the source by executing a model of gas-phase transport using at least the first carbon dioxide concentration increase. Related systems, methods, and articles of manufacture are also described.

Keeling, Ralph F.; Dubey, Manvendra K.

2013-01-29

190

WESTCARB Carbon Atlas  

DOE Data Explorer

The West Coast Regional Carbon Sequestration Partnership (known as WESTCARB) was established in Fall 2003. It is one of seven research partnerships co-funded by DOE to characterize regional carbon sequestration opportunities and conduct pilot-scale validation tests. The California Energy Commission manages WESTCARB and is a major co-funder. WESTCARB is characterizing the extent and capacity of geologic formations capable of storing CO2, known as sinks. Results are entered into a geographic information system (GIS) database, along with the location of major CO2-emitting point sources in each of the six WESTCARB states, enabling researchers and the public to gauge the proximity of candidate CO2 storage sites to emission sources and the feasibility of linking them via pipelines. Specifically, the WESTCARB GIS database (also known as the carbon atlas) stores layers of geologic information about potential underground storage sites, such as porosity and nearby fault-lines and aquifers. Researchers use these data, along with interpreted geophysical data and available oil and gas well logs to estimate the region's potential geologic storage capacity. The database also depicts existing pipeline routes and rights-of-way and lands that could be off-limits, which can aid the development of a regional carbon management strategy. The WESTCARB Carbon Atlas, which is accessible to the public, provides a resource for public discourse on practical solutions for regional CO2 management. A key WESTCARB partner, the Utah Automated Geographic Reference Center, has developed data serving procedures to enable the WESTCARB Carbon Atlas to be integrated with those from other regional partnerships, thereby supporting the U.S. Department of Energy's national carbon atlas, NATCARB

191

Polymerized carbon nitride nanobells  

NASA Astrophysics Data System (ADS)

Well-aligned carbon nitride nanotubes are fabricated by microwave plasma assisted chemical vapor deposition using iron as the catalyst. These nanotubes are linearly polymerized by carbon nitride nanobells with catalyst particles in the root, as revealed by high-resolution transmission electron microscopy. Carbon nitride nanotube film is analyzed by x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and Raman spectroscopy. Both XPS and AES reveal a nitrogen content of about 2% in the film. Raman spectroscopy exhibits a good crystallization of these carbon nitride nanotubes. Electron energy loss spectroscopy is used to study the local distribution of nitrogen in a single nanotube, which indicates that nitrogen prefers to locate at curved graphite sheets, at the top of the nanobells, and that incorporation of nitrogen results in the decrease of the crystallization. Based on these results, a growth model is proposed to explain this periodically stacked nanobell structure. In this model, we propose that graphite sheets only precipitate along the surface of catalyst particles and that lower growth rate at the top curve surface of the bell-like catalyst particle is the key factor influencing formation of this special microstructure. A heterojunction between a tubular carbon nanotube and a carbon nitride nanobell also has been fabricated by a two-step growth technique. And short carbon nitride nanotubes with a few nanobells or even just one nanobell are obtained by both physical and chemical methods. Furthermore, we studied the field emission properties and have obtained a threshold field of as low as about 1 V/?m. A novel side-emission mechanism has been proposed based on the special polymerized nanobell structures.

Zhang, G. Y.; Ma, X. C.; Zhong, D. Y.; Wang, E. G.

2002-06-01

192

High-resolution Carbon/Carbon Multilayers  

NASA Astrophysics Data System (ADS)

To synthesize X-ray optical multilayers showing both high resolution and high reflectivity, spacer and absorber materials with low absorption coefficients for the desired spectral range are required. Beside the well-known candidates the material system Carbon / Carbon is interesting because of its low absorption coefficient over a wide spectral range and the opportunity, to deposit C-layers with different modifications, i.e. different optical properties. Simulations of C/C multilayers with different period thicknesses d and single layer densities ? show, that reflectivities R (Cu K? ) > 80% and a resolution ??~0.002° can be achieved for C/C layer stacks with d= 3 nm and N= 1000 periods. An advanced large area Pulsed Laser Deposition (LA-PLD) technology was used to deposit C/C multilayers on Si-substrates up to 4" diameter. The carbon film growth conditions for the spacer and absorber layers were optimised by the variation of selected laser parameters like pulse energy and ablation wavelength, to achieve a sufficient density contrast and smooth interfaces. C/C multilayers with period thickness d= 1.1...7.0 nm and more than 500 periods were deposited. The X-ray optical performance of the C/C multilayers was characterized by means of X-ray reflectometry. A reflectivity R > 50 % (CuK?) was measured for C/C multilayers with d= 17.2 nm and N= 106 periods. A peak resolution (??/?) ~ 1.1 % was obtained for a C/C multilayer structure with N= 80 periods and a period thickness d= 1.1nm. Results of TEM investigations indicate a regular morphology as well as smooth interfaces in the C-C layer stacks. Low compressive stresses were determined in C/C multilayers with different period thicknesses using X-ray diffraction techniques.

Baranov, Alexander M.; Dietsch, Reiner; Holz, Thomas; Menzel, Maik; Weissbach, Danny; Scholz, Roland; Melov, Valeri; Schreiber, Juergen

2002-12-01

193

Acoustical studies of damage mechanisms in carbon-carbon during first carbonization  

Microsoft Academic Search

Acoustical studies of damage mechanisms in carbon-carbon during first carbonization are reported. Normal and anomalous temperature profiles are treated to investigate the damage mechanisms. Small plates of carbon-carbon were suspended in a small research autoclave with acoustic emission (AE) sensors, thermocouples, and a gas-flow meter to monitor the state of the materials during the 25°C to 700°C temperature ramp. A

B. R. Tittmann

1989-01-01

194

Carbon fuel particles used in direct carbon conversion fuel cells  

DOEpatents

A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

Cooper, John F.; Cherepy, Nerine

2012-10-09

195

Carbon fuel particles used in direct carbon conversion fuel cells  

DOEpatents

A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

Cooper, John F. (Oakland, CA); Cherepy, Nerine (Oakland, CA)

2012-01-24

196

Carbon fuel particles used in direct carbon conversion fuel cells  

DOEpatents

A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

Cooper, John F. (Oakland, CA); Cherepy, Nerine (Oakland, CA)

2011-08-16

197

Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells  

DOEpatents

A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

Cooper, John F. (Oakland, CA); Cherepy, Nerine (Oakland, CA)

2008-10-21

198

Response of carbon-carbon composites to challenging environments  

NASA Technical Reports Server (NTRS)

This paper presents results from material performance evaluations of oxidation-resistant carbon-carbon composites intended for multiuse aerospace applications, which cover the effects of the following environmental parameters: the oxidizing nature of the environments (including both high and low oxygen partial pressures), high temperatures, moisture, cyclic temperature service, and foreign-object impact. Results are presented for the carbon-carbon material currently in use as the thermal-protection-system material on Space Shuttle, as well as for newer and more advanced structural forms of carbon-carbon composites.

Maahs, Howard G.; Ohlhorst, Craig W.; Barrett, David M.; Ransone, Philip O.; Sawyer, J. Wayne

1988-01-01

199

CarbonTracker  

NSDL National Science Digital Library

This portal provides information about the National Oceanic and Atmospheric Administration (NOAA) Earth System Research Laboratory (ERSL) CarbonTracker, a system to keep track of carbon dioxide uptake and release at the Earth's surface over time. CarbonTracker produces model predictions of atmospheric CO2 mole fractions, to be compared with the observed atmospheric CO2 mole fractions. Materials available at the site include CO2 flux maps, flux time series graphs, carbon 'weather' maps, and CO2 concentration time series graphs. A download (FTP) page provides access to datasets on 3-D CO2 mole fractions, weekly fluxes, atmospheric CO2 observations, and to the CarbonTracker source code. There is also a link to the Interactive Atmospheric Data Visualization (IADV) tool, a data explorarion tool that enables users to view all data including near real-time preliminary measurement results, obtain details about each sampling location, manipulate and compare NOAA ESRL datasets, create custom graphs, and view their plots online or save them for later use. Other materials include subscription information for an email list, a glossary, and a bibliography.

200

Big Sky Carbon Atlas  

DOE Data Explorer

The Big Sky Carbon Atlas is an online geoportal designed for you to discover, interpret, and access geospatial data and maps relevant to decision support and education on carbon sequestration in the Big Sky Region. In serving as the public face of the Partnership's spatial Data Libraries, the Atlas provides a gateway to geographic information characterizing CO2 sources, potential geologic sinks, terrestrial carbon fluxes, civil and energy infrastructure, energy use, and related themes. In addition to directly serving the BSCSP and its stakeholders, the Atlas feeds regional data to the NatCarb Portal, contributing to a national perspective on carbon sequestration. Established components of the Atlas include a gallery of thematic maps and an interactive map that allows you to: • Navigate and explore regional characterization data through a user-friendly interface • Print your map views or publish them as PDFs • Identify technical references relevant to specific areas of interest • Calculate straight-line or pipeline-constrained distances from point sources of CO2 to potential geologic sink features • Download regional data layers (feature under development) (Acknowledgment to the Big Sky Carbon Sequestration Partnership (BSCSP); see home page at http://www.bigskyco2.org/)

Carbon Sequestration Partnership, Big Sky [BSCSP; ,

201

Carbon-particle generator  

DOEpatents

A method and apparatus whereby small carbon particles are made by pyrolysis of a mixture of acetylene carried in argon. The mixture is injected through a nozzle into a heated tube. A small amount of air is added to the mixture. In order to prevent carbon build-up at the nozzle, the nozzle tip is externally cooled. The tube is also elongated sufficiently to assure efficient pyrolysis at the desired flow rates. A key feature of the method is that the acetylene and argon, for example, are premixed in a dilute ratio, and such mixture is injected while cool to minimize the agglomeration of the particles, which produces carbon particles with desired optical properties for use as a solar radiant heat absorber.

Hunt, A.J.

1982-09-29

202

Carbon Nanotubes for Supercapacitor  

NASA Astrophysics Data System (ADS)

As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs) and their composites. The purpose is to give a comprehensive understanding of the advantages and disadvantages of carbon nanotubes-related supercapacitor materials and to find ways for the improvement in the performance of supercapacitor. We first discussed the effects of physical and chemical properties of pure carbon nanotubes, including size, purity, defect, shape, functionalization, and annealing, on the supercapacitance. The composites, including CNTs/oxide and CNTs/polymer, were further discussed to enhance the supercapacitance and keep the stability of the supercapacitor by optimally engineering the composition, particle size, and coverage.

Pan, Hui; Li, Jianyi; Feng, Yuan Ping

2010-03-01

203

Carbon Nanotubes for Supercapacitor  

PubMed Central

As an electrical energy storage device, supercapacitor finds attractive applications in consumer electronic products and alternative power source due to its higher energy density, fast discharge/charge time, low level of heating, safety, long-term operation stability, and no disposable parts. This work reviews the recent development of supercapacitor based on carbon nanotubes (CNTs) and their composites. The purpose is to give a comprehensive understanding of the advantages and disadvantages of carbon nanotubes-related supercapacitor materials and to find ways for the improvement in the performance of supercapacitor. We first discussed the effects of physical and chemical properties of pure carbon nanotubes, including size, purity, defect, shape, functionalization, and annealing, on the supercapacitance. The composites, including CNTs/oxide and CNTs/polymer, were further discussed to enhance the supercapacitance and keep the stability of the supercapacitor by optimally engineering the composition, particle size, and coverage.

2010-01-01

204

Carbon Fibers Conductivity Studies  

NASA Technical Reports Server (NTRS)

In an attempt to understand the process of electrical conduction in polyacrylonitrile (PAN)-based carbon fibers, calculations were carried out on cluster models of the fiber consisting of carbon, nitrogen, and hydrogen atoms using the modified intermediate neglect of differential overlap (MINDO) molecular orbital (MO) method. The models were developed based on the assumption that PAN carbon fibers obtained with heat treatment temperatures (HTT) below 1000 C retain nitrogen in a graphite-like lattice. For clusters modeling an edge nitrogen site, analysis of the occupied MO's indicated an electron distribution similar to that of graphite. A similar analysis for the somewhat less stable interior nitrogen site revealed a partially localized II electron distribution around the nitrogen atom. The differences in bonding trends and structural stability between edge and interior nitrogen clusters led to a two-step process proposed for nitrogen evolution with increasing HTT.

Yang, C. Y.; Butkus, A. M.

1980-01-01

205

Orbiting Carbon Observatory  

NASA Technical Reports Server (NTRS)

Human impact on the environment has produced measurable changes in the geological record since the late 1700s. Anthropogenic emissions of CO2 today may cause the global climate to depart for its natural behavior for many millenia. CO2 is the primary anthropogenic driver of climate change. The Orbiting Carbon Observatory goals are to help collect measurements of atmospheric CO2, answering questions such as why the atmospheric CO2 buildup varies annually, the roles of the oceans and land ecosystems in absorbing CO2, the roles of North American and Eurasian sinks and how these carbon sinks respond to climate change. The present carbon cycle, CO2 variability, and climate uncertainties due atmospheric CO2 uncertainties are highlighted in this presentation.

Miller, Charles E.

2005-01-01

206

Solid State Carbon Monoxide Sensor  

NASA Technical Reports Server (NTRS)

A means for detecting carbon monoxide which utilizes an un-heated catalytic material to oxidize carbon monoxide at ambient temperatures. Because this reaction is exothermic, a thermistor in contact with the catalytic material is used as a sensing element to detect the heat evolved as carbon monoxide is oxidized to carbon dioxide at the catalyst surface, without any heaters or external heating elements for the ambient air or catalytic element material. Upon comparison to a reference thermistor, relative increases in the temperature of the sensing thermistor correspond positively with an increased concentration of carbon monoxide in the ambient medium and are thus used as an indicator of the presence of carbon monoxide.

Upchurch, Billy T. (Inventor); Wood, George M. (Inventor); Schryer, David R. (Inventor); Leighty, Bradley D. (Inventor); Oglesby, Donald M. (Inventor); Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); DAmbrosia, Christine M. (Inventor)

1999-01-01

207

Carbon microstructures for electrochemical studies  

SciTech Connect

Thin layers of photoresist were spin coated onto silicon wafers, and then carbonized to form smooth carbon films by heating in nitrogen for 1 hour at temperatures between 600 to 1100 C. Well-defined carbon microstructures on Si wafers that are being considered for electrodes in a microbattery concept were obtained by additional processing steps involving patterning and lithography of the photoresist prior to carbonization. The status of the fabrication of carbon microelectrodes obtained by pyrolysis of photoresist, characterization of the carbons by surface-sensitive techniques and electrochemical analysis by cyclic voltammetry of the I{sup -}/I{sub 3}{sup -} redox reaction is described.

Kostecki, Robert; Song, Xiang Yun; Kinoshita, Kim

2001-06-22

208

Carbon Cycle and Life  

NSDL National Science Digital Library

In this lesson, learners explore the steps in the carbon cycle and draw conclusions about the importance of the carbon cycle in the planetary temperature system. The lesson models scientific inquiry using the 5E instructional model and includes teacher notes, prerequisite concepts, common misconceptions, student journal and reading. This is lesson six in the Astro-Venture Geology Training Unit that was developed to increase students' awareness of and interest in astrobiology and the many career opportunities that utilize science, math and technology skills. The lessons are designed for educators to use with the Astro-Venture multimedia modules.

209

Pitch carbon microsphere composite  

NASA Technical Reports Server (NTRS)

Petroleum pitch carbon microspheres were prepared by flash heating emulsified pitch and carbonizing the resulting microspheres in an inert atmosphere. Microsphere composites were obtained from a mixture of microspheres and tetraester precursor pyrrone powder. Scanning electron micrographs of the composite showed that it was an aggregate of microspheres bonded together by the pyrrone at the sphere contact points, with voids in and among the microspheres. Physical, thermal, and sorption properties of the composite are described. Composite applications could include use as a honeycomb filler in elevated-temperature load-bearing sandwich boards or in patient-treatment tables for radiation treatment of tumors.

Price, H. L.; Nelson, J. B.

1977-01-01

210

Carbon Dioxide Exercise  

NSDL National Science Digital Library

In this activity, students work in groups, plotting carbon dioxide concentrations over time on overheads and estimating the rate of change over five years. Stacked together, the overheads for the whole class show an increase on carbon dioxide over five years and annual variation driven by photosynthesis. This exercise enables students to practice basic quantitative skills and understand how important sampling intervals can be when studying changes over time. A goal is to see how small sample size may give incomplete picture of data.

Richardson, Randy; Collection, Serc -.

211

Ultrahard carbon nanocomposite films  

SciTech Connect

Modest thermal annealing to 600 C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5--10%. The authors report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approximately} 15% due to the development of the nanocomposite structure.

SIEGAL,MICHAEL P.; TALLANT,DAVID R.; PROVENCIO,PAULA P.; OVERMYER,DONALD L.; SIMPSON,REGINA L.; MARTINEZ-MIRANDA,L.J.

2000-01-27

212

Carbon wastewater treatment process  

NASA Technical Reports Server (NTRS)

A new powdered-carbon treatment process is being developed for the elimination of the present problems, associated with the disposal of biologically active sewage waste solids, and with water reuse. This counter-current flow process produces an activated carbon, which is obtained from the pyrolysis of the sewage solids, and utilizes this material to remove the adulterating materials from the water. Additional advantages of the process are the elimination of odors, the removal of heavy metals, and the potential for energy conservation.

Humphrey, M. F.; Simmons, G. M.; Dowler, W. L.

1974-01-01

213

Nanomodified Carbon/Carbon Composites for Intermediate Temperature.  

National Technical Information Service (NTIS)

An improved Carbon/Carbon Composite (CCC) with enhanced thermo- oxidative resistant performance at intermediate temperatures (700 to 1200 degrees F) was investigated. A nanophase was introduced into the (CCC NCCC) prior to cure for improved and maintained...

J. H. Koo L. A. Pilato C. U. Pittman P. Winzek

2004-01-01

214

Nanomodified Carbon/Carbon Composites for Intermediate Temperature.  

National Technical Information Service (NTIS)

An improved Carbon/Carbon Composite (CCC) with enhanced thermo- oxidative resistant performance at intermediate temperatures (371 to 650 C) is being developed. A nanophase is introduced into the CCC prior to cure for improved and maintained mechanical str...

G. E. Wissler J. H. Koo L. A. Pilato

2007-01-01

215

Carbon tips for all-carbon single-molecule electronics.  

PubMed

We present here an exhaustive ab initio study of the use of carbon-based tips as electrodes in single-molecule junctions. Motivated by recent experiments, we show that carbon tips can be combined with other carbon nanostructures, such as graphene, to form all-carbon molecular junctions with molecules like benzene or C60. Our results show that the use of carbon tips can lead to relatively conductive molecular junctions. However, contrary to junctions formed with standard metals, the conductance traces recorded during the formation of the all-carbon single-molecule junctions do not exhibit clear conductance plateaus, which can be attributed to the inability of the hydrogenated carbon tips to form chemical bonds with the organic molecules. Additionally, we explore here the use of carbon tips for scanning tunneling microscopy and show that they are well suited for obtaining sample images with atomic resolution. PMID:24838986

Dappe, Y J; González, C; Cuevas, J C

2014-05-29

216

Carbon tips for all-carbon single-molecule electronics  

NASA Astrophysics Data System (ADS)

We present here an exhaustive ab initio study of the use of carbon-based tips as electrodes in single-molecule junctions. Motivated by recent experiments, we show that carbon tips can be combined with other carbon nanostructures, such as graphene, to form all-carbon molecular junctions with molecules like benzene or C60. Our results show that the use of carbon tips can lead to relatively conductive molecular junctions. However, contrary to junctions formed with standard metals, the conductance traces recorded during the formation of the all-carbon single-molecule junctions do not exhibit clear conductance plateaus, which can be attributed to the inability of the hydrogenated carbon tips to form chemical bonds with the organic molecules. Additionally, we explore here the use of carbon tips for scanning tunneling microscopy and show that they are well suited for obtaining sample images with atomic resolution.

Dappe, Y. J.; González, C.; Cuevas, J. C.

2014-05-01

217

Residual Stress in a 3D Carbon-Carbon Composite.  

National Technical Information Service (NTIS)

Residual stress is measured in a thin slice from a carbon-carbon composite with a 3D Cartesian weave. The curvature of a slice of asymmetric cross section indicates the amount of stress caused by thermal expansion anisotropy.

L. A. Feldman

1986-01-01

218

Carbon Residue Studies with a Micro Carbon Residue Tester.  

National Technical Information Service (NTIS)

A test procedure for the coking propensity of gas turbine lubricants was developed using the 'Micro Carbon Residue Tester-100' (MCRT-100). The MCRT-1009, a microprocessor controlled heating unit, was evaluated for its ability to determine carbon residue i...

W. Bochartz

1986-01-01

219

Carbon Dioxide Absorption and Desorption by Tris with Carbonic Anhydrase.  

National Technical Information Service (NTIS)

One concept of carbon dioxide control in aerospace vehicle atmosphere regeneration and control requires an efficient gas absorber which is effective in a moist gas stream. A tris (tri(hydroxymethyl)aminomethane) solution containing the enzyme, carbonic an...

J. P. Allen

1967-01-01

220

Carbon/Carbon and Ceramic Composites Made by Aerospatiale.  

National Technical Information Service (NTIS)

Inorganic composites devoted to strategic and space applications are considered. The processing and properties of carbon/carbon and ceramic composites are considered. Present and future applications are discussed.

B. Capdepuy

1992-01-01

221

Deep Recycling of Carbon  

NASA Astrophysics Data System (ADS)

While most of the subducted H2O is recycled at shallow and subarc depths, carbon is less readily mobilized and susceptive to complex redox processes involving CO2 in solids, fluids and melts, elemental carbon, Fe- and Si- carbides, and methane. Here I review the various ways of recycling carbon during subduction and present a spectrum of possible reaction products in the mantle. Metamorphic reactions liberate <20% of the subducted CO2 to the subarc region (Connolly 2005, EPSL). Larger amounts might be mobilized through (sediment) melting. Although the wet pelite solidus is only shifted by 30-50 oC (at 3 GPa) with carbonates, the latter remain stable with melts that are saturated in a H2O+CO2-fluid. Complete dissolution of carbonates requires temperatures above any predicted subduction geotherm. Carbonated sediments yield CO2-rich phonolites to 5 GPa but carbonatites at higher pressures. The silicate melts become increasingly potassic with pressure, while the alkali-rich carbonatites have their highest K/Na at 8 GPa, slightly decreasing to 13 GPa and become sodic with the disappearance of residual cpx at ~16 GPa. What may happen when carbonated pelite derived melts migrate into the mantle is illustrated in Central Italy: in this case, it can be experimentally demonstrated that hybridization of ultrapotassic phonolitic melts with ~2 wt% H2O and ~6 wt% CO2 in the mantle results in the primitive parents of the ultrapotassic kamafugite suites which have ~43 wt% SiO2. Hence, despite a crustal isotopic signature of C, O, and Sr in these rocks, the CO2 of the Italian magmatism does not stem from assimilation in the crust but from melts derived from subducted marine carbonates mixed with pelagic clays and then reacted in the mantle. The migration of CO2-bearing fluids and melts into the mantle may lead to a redox-shock. Where high liquid/mantle ratios prevail, carbonatites rest in their oxidized form and may only freeze in relatively cold lithospheric keels where they form metasomatic zones prone to generate kimberlites in the context of a much later remelting event. Where the redox-capacity of the oxidized crust-derived material is subequal to the reduced mantle, iron carbides are to be expected. The eutectic in the Fe-Ni-C system is at lower temperatures than the mantle adiabat, leading to the distinct possibility that such zones entrained in global mantle convection will contain ~1% of eutectic Fe-C-melt. When the amount of subduction derived CO2 is small compared to the redox capacity of a metal bearing reduced mantle, diamond will form, but diamond itself is not truly reducing at high pressures. The most extreme reducing case leads to moissanite (found together with diamond), which isotopic signature implies involvement of organically derived carbon. Moissanite (SiC) only forms at fO2 <6-8 log units below iron-wustite and coexists with mantle silicates that have an XMg of 0.995-0.998. Our calculations show that a fluid or melt with a bulk, which is slightly more reduced than the CO2-H2O-tieline in C-O-H, may evolve to ultra-reduced residual C-H-rich fluids through removal of CO2 (through carbonate precipitation) followed by removal of H2O (through hydrous silicate formation). As SiC may only be in grain scale equilibrium with the mantle and requires a protracted fluid-fractionation, we propose that SiC is generally a low temperature phase formed from originally already reducing fluids involving organic carbon and hence subduction.

Schmidt, M. W.

2012-12-01

222

Method of Manufacturing Carbon Fiber Reinforced Carbon Composite Valves  

NASA Technical Reports Server (NTRS)

A method for forming a carbon composite valve for internal combustion engines is discussed. The process includes the steps of braiding carbon fiber into a rope thereby forming a cylindrically shaped valve stem portion and continuing to braid said fiber while introducing into the braiding carbon fiber rope a carbon matrix plug having an outer surface in a net shape of a valve head thereby forming a valve head portion. The said carbon matrix plug acting as a mandrel over which said carbon fiber rope is braided, said carbon fiber rope and carbon matrix plug forming a valve head portion suitable for mating with a valve seat; cutting said braided carbon valve stem portion at one end to form a valve tip and cutting said braided carbon fiber after said valve head portion to form a valve face and thus provide a composite valve preform; and densifying said preform by embedding the braided carbon in a matrix of carbon to convert said valve stem portion to a valve stem and said valve head portion to a valve head thereby providing said composite valve.

Rivers, H. Kevin (Inventor); Ransone, Philip O. (Inventor); Northam, G. Burton (Inventor)

1998-01-01

223

Carbon-hydrogen bonding in near-frictionless carbon  

Microsoft Academic Search

The uniquely low friction behavior of near-frictionless carbon (NFC) as compared to conventional diamondlike carbon (DLC) is determined by the bonding within the film. Inelastic neutron scattering (INS) and Fourier transform infrared (FTIR) spectroscopy were used to probe the bonding environment of carbon and hydrogen; both INS and FTIR can probe the whole sample. Previous work has focused on surface

Jackie A. Johnson; John B Woodford; Deepak Rajput; Alexander I Kolesnikov; John A Schleuter; Osman L Eryilmaz; Ali Erdemir

2008-01-01

224

Carbon Cycle 2.0: Berend Smit: Carbon Capture  

ScienceCinema

Feb. 3, 2010: Humanity emits more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future.

Berend Smit

2010-09-01

225

Carbon Cycle 2.0: Berend Smit: Carbon Capture  

SciTech Connect

Feb. 3, 2010: Humanity emits more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future.

Berend Smit

2010-02-16

226

Where is mantle's carbon?  

Microsoft Academic Search

Due to the strongly reducing conditions (the presence of metallic iron was suggested both by experiments [1] and theory [2]), diamond was believed to be the main host of carbon through most of the lower mantle [3]. We showed [4] that cementite Fe3C is another good candidate to be the main host of \\

A. R. Oganov; S. Ono; Y. Ma

2008-01-01

227

GRANULAR ACTIVATED CARBON INSTALLATIONS  

EPA Science Inventory

This paper presents a compilation and summary of design criteria, performance, and cost data from 22 operating municipal and industrial granular activated carbon (GAC) installations that treat water and wastewater or process food and beverage products. Guidance for using this inf...

228

Chloroplastic Carbonic Anhydrases  

Microsoft Academic Search

In biological systems the interconversion between CO2 and HCO?+H+ is catalyzed by carbonic anhydrases (CAs). They belong to three evolutionary unrelated gene families designated ?-, ?- and ?-CA1 with no significant sequence homologies between representatives of the different CA families. In the stroma of higher plant chloroplasts a ?-CA is one of the most abundant proteins. Its specific function is

Göran Samuelsson; Jan Karlsson

229

Carbon smackdown: wind warriors  

SciTech Connect

July 16. 2010 carbon smackdown summer lecture: learn how Berkeley Lab scientists are developing wind turbines to be used in an urban setting, as well as analyzing what it will take to increase the adoption of wind energy in the U.S.

Glen Dahlbacka of the Accelerator & Fusion Research Division and Ryan Wiser of the Environmental Energy Technologies Division are the speakers.

2010-07-21

230

Carbon smackdown: wind warriors  

ScienceCinema

July 16. 2010 carbon smackdown summer lecture: learn how Berkeley Lab scientists are developing wind turbines to be used in an urban setting, as well as analyzing what it will take to increase the adoption of wind energy in the U.S.

Glen Dahlbacka of the Accelerator & Fusion Research Division and Ryan Wiser of the Environmental Energy Technologies Division are the speakers.

2010-09-01

231

Carbon dioxide fixation.  

National Technical Information Service (NTIS)

Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO(sub 2) conv...

E. Fujita

2000-01-01

232

Polyimide/carbon Nanocomposites  

NASA Technical Reports Server (NTRS)

The goal of this product is to design and characterize well-defined conductive nanocomposite materials. The materials will be composed of a polymer matrix composed of rigid-backbone polyimides, and will be filled with modified or unmodified multi-walled carbon nanotubes (MWNTs). The ultimate design of this project is to create composite materials with optical clarity and a high conductivity.

Harris, Frank W.

2003-01-01

233

Bench Remarks: Carbon Dioxide.  

ERIC Educational Resources Information Center

Discusses the properties of carbon dioxide in its solid "dry ice" stage. Suggests several demonstrations and experiments that use dry ice to illustrate Avogadro's Law, Boyle's Law, Kinetic-Molecular Theory, and the effects of dry ice in basic solution, in limewater, and in acetone. (TW)

Bent, Henry A.

1987-01-01

234

Titanium carbon nitride coating  

SciTech Connect

The purpose of this investigation was to determine the advantages of titanium carbon nitride (TiCN) coated tools. Cutting tests were conducted comparing TiCN coating directly against titanium nitride (TiN) coated and uncoated T-15 CPM end mills.

Nance, S.D.

1992-04-01

235

From Coffee to Carbon  

NSDL National Science Digital Library

In this activity, learners place cards featuring biological structures in order by their relative size from largest to smallest. The cards feature structures ranging from the carbon atom (340 pm) to a skin cell (30 μm) to a coffee bean (8 mm). This activity can also be used as a formative assessment or an anticipatory set.

Malone, Molly; Avery, Sheila; Conley, Thomas; Starr, Harmony

2008-01-01

236

Carbon smackdown: smart windows  

ScienceCinema

August 3, 2010 Berkeley Lab talk: In the fourth of five Carbon Smackdown matches, Berkeley Lab researchers Delia Milliron of the Materials Sciences Division and Stephen Selkowitz of the Environmental Energy Technologies Division talk about their work on energy-saving smart windows.

Delia Milliron

2010-09-01

237

Comparing Carbon Calculators  

NSDL National Science Digital Library

Carbon calculators, no matter how well intended as tools to help measure energy footprints, tend to be black boxes and can produce wildly different results, depending on the calculations used to weigh various energy factors. By comparing different calculators, learners can analyze which ones are the most accurate and relevant, and which are the most transparent.

Mccaffrey, Mark

238

Carbon Nanotube Solar Cells  

PubMed Central

We present proof-of-concept all-carbon solar cells. They are made of a photoactive side of predominantly semiconducting nanotubes for photoconversion and a counter electrode made of a natural mixture of carbon nanotubes or graphite, connected by a liquid electrolyte through a redox reaction. The cells do not require rare source materials such as In or Pt, nor high-grade semiconductor processing equipment, do not rely on dye for photoconversion and therefore do not bleach, and are easy to fabricate using a spray-paint technique. We observe that cells with a lower concentration of carbon nanotubes on the active semiconducting electrode perform better than cells with a higher concentration of nanotubes. This effect is contrary to the expectation that a larger number of nanotubes would lead to more photoconversion and therefore more power generation. We attribute this to the presence of metallic nanotubes that provide a short for photo-excited electrons, bypassing the load. We demonstrate optimization strategies that improve cell efficiency by orders of magnitude. Once it is possible to make semiconducting-only carbon nanotube films, that may provide the greatest efficiency improvement.

Klinger, Colin; Patel, Yogeshwari; Postma, Henk W. Ch.

2012-01-01

239

Carbon Dioxide Increases  

NSDL National Science Digital Library

In this problem set, learners will analyze the Keeling Curve showing carbon dioxide concentration in the atmosphere since 1985 to answer a series of questions. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

240

GLOBAL TERRESTRIAL CARBON CYCLE  

EPA Science Inventory

There is great uncertainty with regard to the future role of the terrestrial biosphere in the global carbon cycle, arising from both an inadequate understanding of current pools and fluxes as well as the potential effects of rising atmospheric concentrations of CO, on natural eco...

241

Mass carbon monoxide poisoning  

PubMed Central

The largest occurrence of carbon monoxide poisoning in Britain demonstrates the potential for mass accidental poisoning. It emphasises the need for strict public health controls and the importance of good liaison between emergency services to ensure that such events are quickly recognised and that the necessary resources are organised.

McGuffie, C; Wyatt, J; Kerr, G; Hislop, W

2000-01-01

242

Carbon Sorption Cryogenic Regenerator  

NASA Technical Reports Server (NTRS)

Liquid-helium refrigerator includes regenerator filled with carbon sorbent made from Saran polyvinylidene chloride. Material results in lower operating temperatures and longer times between maintenance than comparable refrigerators containing other regenerators. Sorbent material machined to various configurations to fit inside cylindrical regenerator can. Configuration chosen with regard to heat capacity, pressure drop, and rate of sorption.

Jones, Jack A.; Petrick, S. Walter; Britcliffe, Michael J.

1989-01-01

243

Carbon cloth supported electrode  

DOEpatents

A flow-by anode is disclosed made by preparing a liquid suspension of about to about 18% by weight solids, the solids comprising about 3.5 to about 8% of a powdered catalyst of platinum, palladium, palladium oxide, or mixtures thereof; about 60 to about 76% carbon powder (support) having a particle size less than about 20 m.mu.m and about 20 to about 33% of an inert binder having a particle size of less than about 500 m.mu.m. A sufficient amount of the suspension is poured over a carbon cloth to form a layer of solids about 0.01 to about 0.05 cm thick on the carbon cloth when the electrode is completed. A vacuum was applied to the opposite side of the carbon cloth to remove the liquid and the catalyst layer/cloth assembly is dried and compressed at about 10 to about 50 MPa's. The binder is then sintered in an inert atmosphere to complete the electrode. The electrode is used for the oxidation of sulfur dioxide in a sulfur based hybrid cycle for the decomposition of water.

Lu, Wen-Tong P. (Upper St. Clair, PA); Ammon, Robert L. (Baldwin both of, PA)

1982-01-01

244

Transmissivity of carbon monoxide  

NASA Technical Reports Server (NTRS)

The line strengths and self- and nitrogen-broadened half widths for selected lines of the 4.6 micron fundamental band of carbon monoxide were determined. The band strength determined at stp. is higher than previously reported measurements. The half widths agree well with other measurements and calculations.

Drayson, S. R.; Tallamraju, R.; Chaney, L. W.

1973-01-01

245

Carbon isotope fractionation in wood during carbonization  

NASA Astrophysics Data System (ADS)

A significant uncertainty exists as to whether ? 13C values in charcoal meaningfully represent the stable isotopic content of the original material, with studies suggesting variable responses to both natural and laboratory heating. An extensive study was undertaken using fully homogenised samples of wood taken from Eucalyptus spp., Quercus robur and Pinus radiata. The results demonstrate that the duration of heating had no tangible effect on the final composition of the charred material, with the ? 13C and carbon content of wood fixed after 30 min of heating. Furthermore, all three wood types become progressively depleted in 13C with increasing temperature. The results demonstrate that even at temperatures commonly reached in natural fires (<450 °C) isotopic fractionation of up to 1.3‰ can take place indicating that the absolute values obtained from charcoal extracted for paleoenvironmental reconstruction must be interpreted with caution.

Turney, C. S. M.; Wheeler, D.; Chivas, Allan R.

2006-02-01

246

Atmospheric carbon dioxide and carbon reservoir changes.  

PubMed

The net release of CO(2) from the biosphere to the atmosphere between 1850 and 1950 is estimated to amount to 1.2 x 10(9) tons of carbon per year. During this interval, changes in land use reduced the total terrestrial biomass by 7 percent. There has been a smaller reduction in biomass over the last few decades. In the middle 19th century the air had a CO(2) content of approximately 268 parts per millon, and the total increase in atmospheric CO(2) content since 1850 has been 18 percent. Major sinks for fossil fuel CO(2) are the thermocline regions of large oceanic gyres. About 34 percent of the excess CO(2) generated so far is stored in surface and thermocline gyre waters, and 13 percent has been advected into the deep sea. This leaves an airborne fraction of 53 percent. PMID:17759647

Stuiver, M

1978-01-20

247

Dewatering Peat With Activated Carbon  

NASA Technical Reports Server (NTRS)

Proposed process produces enough gas and carbon to sustain itself. In proposed process peat slurry is dewatered to approximately 40 percent moisture content by mixing slurry with activated carbon and filtering with solid/liquid separation techniques.

Rohatgi, N. K.

1984-01-01

248

Carbon Capture: A Technology Assessment.  

National Technical Information Service (NTIS)

Carbon capture and sequestration (CCS) is widely seen as a critical strategy for limiting atmospheric emissions of carbon dioxide (CO2) the principal greenhouse gas linked to global climate change from power plants and other large industrial sources. This...

P. Folger

2013-01-01

249

Calcium carbonate with magnesium overdose  

MedlinePLUS

The combination of calcium carbonate and magnesium is commonly found in antacids, which are medicines that provide heartburn relief. Calcium carbonate with magnesium overdose occurs when someone accidentally or ...

250

Sorption Properties of Activated Carbon.  

National Technical Information Service (NTIS)

Equilibrium adsorption isotherms were determined experimentally at several temperatures for GB, GA, and GF on BPL activated carbon and a a super activated coconut carbon. Prediction of these isotherms using experimental DMMP, CC14 and benzene adsorption d...

E. D. Tolles

1968-01-01

251

Health Effects of Black Carbon  

EPA Science Inventory

The purpose of this presentation is to inform the Mid-Atlantic Diesel Collaborative's stakeholders about the health effects of black carbon and convey the relevance of black carbon to their efforts in reducing diesel emissions....

252

Selective Absorptivity of Carbon Coatings.  

National Technical Information Service (NTIS)

Preliminary solar absorption tests have been made on copper plates with various carbon coatings, and comparisons were made with known high-solar-absorbing coatings. It was demonstrated that certain carbon coatings exhibited higher absorptivity at shorter ...

J. M. Schreyer C. R. Schmitt J. M. Googin H. D. Whitehead

1976-01-01

253

Solvent-Regenerated Activated Carbon.  

National Technical Information Service (NTIS)

Activated carbon has long been used to remove undesired organic chemicals from aqueous solutions such as wastewaters, public water supplies and contaminated groundwaters. The major problem with the use of activated carbon is the high cost of regenerating ...

H. McLaughlin

1988-01-01

254

The Preparation of Carbon Nanotubes  

Microsoft Academic Search

Carbon nanotubes were prepared by dc arc-discharge evaporation of graphite rods, by varying the pressure and the kind of atmospheric gas. Nanotubes, included in the carbon deposit on the cathode, were observed by scanning electron microscopy (SEM).

Yoshinori Ando

1994-01-01

255

Carbon nanotube macroelectronics  

NASA Astrophysics Data System (ADS)

In this dissertation, I discuss the application of carbon nanotubes in macroelectronis. Due to the extraordinary electrical properties such as high intrinsic carrier mobility and current-carrying capacity, single wall carbon nanotubes are very desirable for thin-film transistor (TFT) applications such as flat panel display, transparent electronics, as well as flexible and stretchable electronics. Compared with other popular channel material for TFTs, namely amorphous silicon, polycrystalline silicon and organic materials, nanotube thin-films have the advantages of low-temperature processing compatibility, transparency, and flexibility, as well as high device performance. In order to demonstrate scalable, practical carbon nanotube macroelectroncis, I have developed a platform to fabricate high-density, uniform separated nanotube based thin-film transistors. In addition, many other essential analysis as well as technology components, such as nanotube film density control, purity and diameter dependent semiconducting nanotube electrical performance study, air-stable n-type transistor fabrication, and CMOS integration platform have also been demonstrated. On the basis of the above achievement, I have further demonstrated various kinds of applications including AMOLED display electronics, PMOS and CMOS logic circuits, flexible and transparent electronics. The dissertation is structured as follows. First, chapter 1 gives a brief introduction to the electronic properties of carbon nanotubes, which serves as the background knowledge for the following chapters. In chapter 2, I will present our approach of fabricating wafer-scale uniform semiconducting carbon nanotube thin-film transistors and demonstrate their application in display electronics and logic circuits. Following that, more detailed information about carbon nanotube thin-film transistor based active matrix organic light-emitting diode (AMOLED) displays is discussed in chapter 3. And in chapter 4, a technology to fabricate air-stable n-type semiconducting nanotube thin-film transistor is developed and complementary metal--oxide--semiconductor (CMOS) logic circuits are demonstrated. Chapter 5 discusses the application of carbon nanotubes in transparent and flexible electronics. After that, in chapter 6, a simple and low cost nanotube separation method is introduced and the electrical performance of separated nanotubes with different diameter is studied. Finally, in chapter 7 a brief summary is drawn and some future research directions are proposed with preliminary results.

Zhang, Jialu

256

Where is mantle's carbon?  

NASA Astrophysics Data System (ADS)

Due to the strongly reducing conditions (the presence of metallic iron was suggested both by experiments [1] and theory [2]), diamond was believed to be the main host of carbon through most of the lower mantle [3]. We showed [4] that cementite Fe3C is another good candidate to be the main host of "reduced" carbon in the mantle, reinforcing an earlier hypothesis [5]. The fate of "oxidised" carbon (in subducted slabs) is of particular importance - if carbonates decompose producing fluid CO2, this would have important implications for the chemistry and rheology of the mantle. Knowledge of crystal structures and phase diagrams of carbonates is crucial here. The high-pressure structures of CaCO3 were predicted [6] and subsequently verified by experiments. For MgCO3, Isshiki et al. [7] found a new phase above 110 GPa, and several attempts were made to solve it [8,9]. Here [4], using an evolutionary algorithm for crystal structure prediction [10], we show that there are two post-magnesite phases at mantle-relevant pressure range, one stable at 82-138 GPa, and the other from 138 GPa to ~160 GPa. Both are based on threefold rings of CO4-tetrahedra and are more favourable than all previously proposed structures. We show that through most of the P-T conditions of the mantle, MgCO3 is the major host of oxidized carbon in the Earth. We predict the possibility of CO2 release at the very bottom of the mantle (in SiO2-rich basaltic part of subducted slabs), which could enhance partial melting of rocks and be related to the geodynamical differences between the Earth and Venus. 1.Frost D.J., Liebske C., Langenhorst F., McCammon C.A., Tronnes R.G., Rubie D.C. (2004). Experimental evidence for the existence of iron-rich metal in the Earth's lower mantle. Nature 428, 409-412. 2.Zhang F., Oganov A.R. (2006). Valence and spin states of iron impurities in mantle-forming silicates. Earth Planet. Sci. Lett. 249, 436-443. 3.Luth R.W. (1999). Carbon and carbonates in the mantle. In: Mantle Petrology: Field Observations and High Pressure Experimentation: A Tribute to Francis R. (Joe) Boyd. Geochemical Soc., Special Publication No. 6. Eds: Y. Fei, C.M. Bertka, B.O. Mysen. 4.Oganov A.R., Ono S., Ma Y., Glass C.W., Garcia A. (2008). Novel high-pressure structures of MgCO3, CaCO3 and CO2 and their role in the Earth's lower mantle. Earth Planet. Sci. Lett. 273, 38-47 5.Scott H.P.,, Williams Q., Knittle E. (2001). Stability and equation of state of Fe3C to 73 GPa: Implications for carbon in the Earth's core. Geoph. Res. Lett. 28, 1875-1878. 6.Oganov A.R., Glass C.W., Ono S. (2006). High-pressure phases of CaCO3: crystal structure prediction and experiment. Earth Planet. Sci. Lett. 241, 95-103. 7.Isshiki M., Irifune T., Hirose K., Ono S., Ohishi Y., Watanuki T., Nishibori E., Takadda M., and Sakata M. (2004). Stability of Magnesite and its high-pressure form in the lowermost mantle. Nature 427, 60-63. 8.Skorodumova N.V., Belonoshko A.B., Huang L., Ahuja R., Johansson B. (2005) Stability of the MgCO3 structures under lower mantle conditions. Am. Mineral. 90, 1008-1011. 9.Panero W.R., Kabbes J.E. (2008). Mantle-wide sequestration of carbon in silicates and the structure of magnesite II. Geophys. Res. Lett. 35, L14307. 10.Oganov A.R., Glass C.W. (2006). Crystal structure prediction using ab initio evolutionary algorithms: principles and applications. J. Chem. Phys. 124, art. 244704.

Oganov, A. R.; Ono, S.; Ma, Y.

2008-12-01

257

Synthesis of Carbonated Vernonia Oil  

Microsoft Academic Search

The research objective was to determine whether naturally occurring epoxy functional vernonia oil would result in lower viscosity\\u000a compounds after converting the virgin oil into the cyclic carbonate using supercritical carbon dioxide as the reactant. The\\u000a cyclic carbonate was produced using relatively mild conditions as described in the paper. Carbonated vernonia oil retains\\u000a the characteristic low viscosity of vernonia oil,

Noel Mann; Sharathkumar K. Mendon; James W. Rawlins; Shelby F. Thames

2008-01-01

258

Carbon aerogels for electrochemical applications  

Microsoft Academic Search

A major advantage of highly crosslinked, organic aerogels is the ability to transform many of these materials into electrically conductive carbon aerogels. Carbon aerogels have been formed as monoliths, microspheres, irregularly-shaped powders, and thin film composites. In all cases, the carbon aerogels retain their high surface area (400–800 m2\\/g) and ultrafine cell\\/pore size (<100 nm). Carbon aerogels are being examined

R. W. Pekala; J. C. Farmer; C. T. Alviso; T. D. Tran; S. T. Mayer; J. M. Miller; B. Dunn

1998-01-01

259

Ureilite Carbon and mg Number  

Microsoft Academic Search

Ureilites are carbon-bearing ultramafic achondrites composed primarily of olivine and pyroxene with intergranular fine-grained metal, sulfides, and silicates. Carbon (up to 6.5 wt%) is either amorphous or present as graphite, lonsdaleite, and\\/or diamond. It has been shown that carbon-silicate redox (i.e. \\

P. Hudon; C. Romanek; L. Paddock; D. W. Mittlefehldt

2004-01-01

260

INCCA: Integrated Climate and Carbon.  

National Technical Information Service (NTIS)

The INCCA (Integrated Climate and Carbon) initiative will develop and apply the ability to simulate the fate and climate impact of fossil fuel-derived carbon dioxide (CO(sub 2)) and aerosols on a global scale. Coupled climate and carbon cycle modeling lik...

S. L. Thompson

2001-01-01

261

Regeneration of spent activated carbon  

Microsoft Academic Search

According to this patent application, spent activated carbon is regenerated by contacting it with formaldehyde in an amount sufficient to restore its activation. Following the treatment the regenerated carbon is rinsed to remove residual formaldehyde and is then ready for use. When the activated carbon has lost its reductive and sorbant properties through use, i.e., when it has become 'spent,'

K. Popper; W. M. Camirand; G. S. Williams; E. P. Mecchi

1976-01-01

262

Automating a Building's Carbon Management  

Microsoft Academic Search

Buildings are the largest contributor to the world’s carbon footprint, yet many building managers use only periodic audits to adjust resource consumption and carbon emission levels. The ECView framework leverages existing workflow systems to continually assess a building’s carbon emissions in relation to daily weather, commuting and travel patterns, and changing government regulations.

Geetha Thiagarajan; Venkatesh Sarangan; Ramasubramanian Suriyanarayanan; Pragathichitra Sethuraman; Anand Sivasubramaniam; Avinash Yegyanarayanan

2011-01-01

263

CARBON IN FORESTS: QUALITY MATTERS  

EPA Science Inventory

The nature of carbon in forests is discussed from the perspective of carbon sequestration and global climate change. Carbon inventories, specifically in the area of land use and forestry are reviewed for the Pacific Northwest. Areas vulnerable to climate change with respect to ca...

264

Carbon: electrochemical and physicochemical properties  

Microsoft Academic Search

This book provides a reference source for the application and study of carbon materials in electrochemistry. The first four chapters deal with the physical properties and chemical reactivity of carbon in its many forms. The remaining chapters focus on the role of carbon materials in electrode and electrochemistry applications. The book concludes with a complete listing of recently assigned patents

K Kinoshita

1988-01-01

265

Full Carbon Account for Russia  

Microsoft Academic Search

The Forestry Project (FOR) at IIASA has produced a full carbon account (FCA) for Russia for 1990, together with scenarios for 2010. Currently, there are rather big question marks regarding the existing carbon accounts for Russia, and Russia is critical to the global carbon balance due to its size. IIASA is in a position to perform solid analysis of Russia

S. Nilsson; A. Shvidenko; V. Stolbovoi; M. Gluck; M. Jonas; M. Obersteiner

2000-01-01

266

Carbon Fiber Risk Analysis. [conference  

NASA Technical Reports Server (NTRS)

The scope and status of the effort to assess the risks associated with the accidental release of carbon/graphite fibers from civil aircraft is presented. Vulnerability of electrical and electronic equipment to carbon fibers, dispersal of carbon fibers, effectiveness of filtering systems, impact of fiber induced failures, and risk methodology are among the topics covered.

1979-01-01

267

Carbon sequestration research and development  

Microsoft Academic Search

Predictions of global energy use in the next century suggest a continued increase in carbon emissions and rising concentrations of carbon dioxide (COâ) in the atmosphere unless major changes are made in the way we produce and use energy--in particular, how we manage carbon. For example, the Intergovernmental Panel on Climate Change (IPCC) predicts in its 1995 ''business as usual''

Dave Reichle; John Houghton; Bob Kane; Jim Ekmann

1999-01-01

268

Determination of elemental carbon emission.  

PubMed

The studies on elemental carbon content in the atmospheric air, performed at the air monitoring station in Katowice (Poland), have revealed violations of allowable maximum average annual and diurnal concentrations. Elemental carbon is introduced into the atmosphere mainly as soot generated from combustion processes. This work presents the determination of elemental carbon in emission generated from coal combustion processes. PMID:24221230

Mniszek, W; Wypych, J; Zielonka, U

1994-01-01

269

Getting to Know Global Carbon  

NSDL National Science Digital Library

GLOBE Carbon Cycle is focused on bringing the most cutting edge research and research techniques in the field of terrestrial ecosystem carbon cycling into the classroom. Students can collect data about their school field site through existing GLOBE protocols of phenology, land cover and soils as well as through new protocols focused on biomass and carbon stocks in vegetation.

2013-01-01

270

Dispersion toughened silicon carbon ceramics  

DOEpatents

Fracture resistant silicon carbide ceramics are provided by incorporating therein a particulate dispersoid selected from the group consisting of (a) a mixture of boron, carbon and tungsten, (b) a mixture of boron, carbon and molybdenum, (c) a mixture of boron, carbon and titanium carbide, (d) a mixture of aluminum oxide and zirconium oxide, and (e) boron nitride. 4 figures.

Wei, G.C.

1984-01-01

271

Stronger Carbon Fibers for Reinforced Plastics  

NASA Technical Reports Server (NTRS)

Process makes fibers 70 percent stronger at lower carbonization temperature. Stronger carbon fibers result from benzoic acid pretreatment and addition of acetylene to nitrogen carbonizing atmosphere. New process also makes carbon fibers of higher electrical resistance -- an important safety consideration.

Cagliostro, D. E.; Lerner, N. R.

1983-01-01

272

Model-based estimation of the global carbon budget and its uncertainty from carbon dioxide and carbon isotope records  

Microsoft Academic Search

A global carbon cycle model is used to reconstruct the carbon budget, balancing emissions from fossil fuel and land use with carbon uptake by the oceans, and the terrestrial biosphere. We apply Bayesian statistics to estimate uncertainty of carbon uptake by the oceans and the terrestrial biosphere based on carbon dioxide and carbon isotope records, and prior information on model

Haroon S. Kheshgi; Atul K. Jain; Donald J. Wuebbles

1999-01-01

273

Development of a carbon-carbon hip prosthesis.  

PubMed

This article deals with the use of carbon-fiber-reinforced-carbon materials for the manufacture of hip prosthesis stems. It considers the manufacturing process of carbon-carbon (C-C) composites made of carbon fibers infiltrated either with dense pyrolytic carbon or silicon carbide (SiC) through chemical vapor infiltration. The chemicophysical properties of these composites are examined according to their structures. The long-term response (2 years) of cortical bone to various types of carbon-carbon was evaluated mainly for bone contact and ingrowth. Carbon-carbon coated with calcium phosphate was found to speed up the bone formation as compared to pyrolytic carbon or SiC coatings. The low modulus of elasticity of the C-C materials could be responsible for quicker bone contact as compared to a much stiffer material like sintered aluminum oxide. The biomechanical performance of C-C hip stems was assessed through (a) implantations into cadaver femurs, (b) fatigue testing, and (c) finite element analysis. These tests showed: (a) a better stress transfer as compared to a metal prosthesis having the same design, (b) no fatigue damage, (c) a computerized stem stress distribution in accordance with the fractures obtained during static mechanical testing. PMID:3624286

Christel, P; Meunier, A; Leclercq, S; Bouquet, P; Buttazzoni, B

1987-08-01

274

Contribution of metabolic carbon to mollusc and barnacle shell carbonate  

NASA Astrophysics Data System (ADS)

Carbon in marine calcareous tests is not necessarily derived only from dissolved inorganic carbon (DIG) in ambient sea water; metabolic carbon can also be incorporated into carbonate tests, as shown by experiments using 14C-labelled food during the incubation of sea urchin embryos and coral1,2. 14C-rich organic matter (relative to seawater DIC) from terrestrial vegetation as well as marine organic matter (reflecting seawater DIC) is used as food by marine organisms in near-shore environments. This use provides the basis for a natural experiment on the systematics of metabolic carbon incorporation into carbonate tests. Here we have combined 14C/12C and 13C/12C ratio measurements on both the calcareous and the organic parts of marine organisms and on DIC, plankton and other carbon-bearing materials collected in and around New Haven Harbor (Connecticut, USA) in Long Island Sound, where the various sources of carbon can be identified, and we deduce that a large percentage of the carbon in calcareous tests is metabolic carbon. Thus, it is at best difficult to use the ?13C values of ancient biogenic carbonate from molluscs to predict the ancient ?13C values of seawater DIC

Tanaka, Noriyuki; Monaghan, Marc C.; Rye, Danny M.

1986-04-01

275

A metallic carbon consisting of helical carbon triangle chains  

NASA Astrophysics Data System (ADS)

Carbon is the basis of life on Earth and many technological applications. We computationally report an sp3-hybridization-assembled carbon allotrope constructed by helical triangle chains through the evolutionary structure prediction method. Different from the previous metallic carbon K4, this carbon, called Tri-carbon, is mechanically and dynamically stable at ambient pressure. High ring strain in the carbon triangle blocks forces the C–C bond in Tri-carbon to be a ‘bent bond’, rather than the common single bond in diamond or the ? bond in graphite. Unlike the unstrained sp3-hybridization in semiconductive diamond, valence electrons in the ‘bent bond’ are recombined to form extremely anisotropic sp3-hybridized bonds, thus conferring metallicity to Tri-carbon. Under nonhydrostatic conditions, Tri-carbon shows significantly anisotropic ideal tensile and compressive strength. Tri-carbon is expected to be achieved through chemical methods, such as the synthesis of cyclopropane derivatives (e.g. triangulane and tetrahedrane). These methods eliminate the restriction of ultra-high pressure to obtain metallic carbons.

Hu, Meng; Dong, Xiao; Pan, Yilong; Xu, Bo; Yu, Dongli; He, Julong

2014-06-01

276

Carbon sequestration and its role in the global carbon cycle  

USGS Publications Warehouse

For carbon sequestration the issues of monitoring, risk assessment, and verification of carbon content and storage efficacy are perhaps the most uncertain. Yet these issues are also the most critical challenges facing the broader context of carbon sequestration as a means for addressing climate change. In response to these challenges, Carbon Sequestration and Its Role in the Global Carbon Cycle presents current perspectives and research that combine five major areas: • The global carbon cycle and verification and assessment of global carbon sources and sinks • Potential capacity and temporal/spatial scales of terrestrial, oceanic, and geologic carbon storage • Assessing risks and benefits associated with terrestrial, oceanic, and geologic carbon storage • Predicting, monitoring, and verifying effectiveness of different forms of carbon storage • Suggested new CO2 sequestration research and management paradigms for the future. The volume is based on a Chapman Conference and will appeal to the rapidly growing group of scientists and engineers examining methods for deliberate carbon sequestration through storage in plants, soils, the oceans, and geological repositories.

McPherson, Brian J.; Sundquist, Eric T.

2009-01-01

277

Carbon and carbon-14 in lunar soil 14163  

SciTech Connect

Carbon is removed from the surface of lunar soil 14163 size fractions by combustions at 500 and 1000/sup 0/C in an oxygen stream and the carbon contents and the carbon-14 activities are measured. The carbon contents are inversely correlated with grain size. A measured carbon content of 198 ppM for bulk 14163, obtained by combining the size fraction results, is modified to 109 +- 12 ppM by a carbon contamination correction. This value is in accord with a previous determination, 110 ppM, for bulk 14163. The small (< 53 ..mu..) grains of 14163 had more combusted carbon-14 activity, 31.2 +- 2.5 dpm /kg, than the large (> 53 ..mu..) grains, 11.2 +- 2.0 dpm/kg. The combusted carbon and carbon-14 are attributed mainly to solar-wind implantation. Melt extractions of carbon-14 from the combusted soil samples gave essentially identical activities, 21.0 +- 1.5 and 19.2 +- 2.0 dpm/kg for the small and large grains, and are attributed to cosmic-ray spallation-produced carbon-14.

Fireman, E.L.; Stoenner, R.W.

1981-01-01

278

Development of a carbon formation reactor for carbon dioxide reduction  

NASA Technical Reports Server (NTRS)

Applied research, engineering development, and performance evaluation were conducted on a process for formation of dense carbon by pyrolysis of methane. Experimental research showed that dense (0.7 to 1.6 g/cc bulk density and 1.6 to 2.2 g/cc solid density) carbon can be produced by methane pyrolysis in quartzwool-packed quartz tubes at temperatrues of 1100 to 1300 C. This result supports the condensation theory of pyrolytic carbon formation from gaseous hydrocarbons. A full-scale Breadboard Carbon Formation Reactor (CFR) was designed, fabricated, and tested at 1100 to 1200 C with 380 to 2280 sccm input flows of methane. Single-pass conversion of methane to carbon ranged from 60 to 100 percent, with 89 percent average conversion. Performance was projected for an Advanced Carbon Reactor Subsystem (ACRS) which indicated that the ACRS is a viable option for management of metabolic carbon on long-duration space missions.

Noyes, G.

1985-01-01

279

Erosion of soil organic carbon: implications for carbon sequestration  

USGS Publications Warehouse

Agricultural activities have substantially increased rates of soil erosion and deposition, and these processes have a significant impact on carbon (C) mineralization and burial. Here, we present a synthesis of erosion effects on carbon dynamics and discuss the implications of soil erosion for carbon sequestration strategies. We demonstrate that for a range of data-based parameters from the literature, soil erosion results in increased C storage onto land, an effect that is heterogeneous on the landscape and is variable on various timescales. We argue that the magnitude of the erosion term and soil carbon residence time, both strongly influenced by soil management, largely control the strength of the erosion-induced sink. In order to evaluate fully the effects of soil management strategies that promote carbon sequestration, a full carbon account must be made that considers the impact of erosion-enhanced disequilibrium between carbon inputs and decomposition, including effects on net primary productivity and decomposition rates.

Van Oost, K.; Van Hemelryck, H.; Harden, J. W.

2009-01-01

280

Liner protected carbon-carbon heat pipe concept  

NASA Astrophysics Data System (ADS)

A lightweight, high performance radiator concept using carbon-carbon heat pipes is being developed to support space nuclear power applications, specifically the SP-100 system. Carbon-carbon has been selected as an outer structural tube member because of its high temperature and strength characteristics; however, this material must be protected from the potassium heat pipe working fluid. A metallic liner approach is being taken to provide this fluid barrier. Feasibility issues associated with this approach include materials compatibility, fabricastion of the thin-walled liner, bonding the liner to the carbon-carbon tube, mismatch of coefficient of thermal expansion (CTE), carbon diffusion, and end cap closures. To resolve these issues, a series of test coupons have been fabricated and tested, assessing various liner materials, braze alloys, and substrate precursors. These tests will lead to a final heat pipe architecture, material selection, and component assembly.

Rovang, Richard D.; Hunt, Maribeth E.

1992-01-01

281

Global carbon budget 2013  

NASA Astrophysics Data System (ADS)

Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and a methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates, consistency within and among components, alongside methodology and data limitations. CO2 emissions from fossil-fuel combustion and cement production (EFF) are based on energy statistics, while emissions from land-use change (ELUC), mainly deforestation, are based on combined evidence from land-cover change data, fire activity associated with deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the annual changes in concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in SOCEAN is evaluated for the first time in this budget with data products based on surveys of ocean CO2 measurements. The global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models forced by observed climate, CO2 and land cover change (some including nitrogen-carbon interactions). All uncertainties are reported as ±1?, reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2003-2012), EFF was 8.6 ± 0.4 GtC yr-1, ELUC 0.9 ± 0.5 GtC yr-1, GATM 4.3 ± 0.1 GtC yr-1, SOCEAN 2.5 ± 0.5 GtC yr-1, and SLAND 2.8 ± 0.8 GtC yr-1. For year 2012 alone, EFF grew to 9.7 ± 0.5 GtC yr-1, 2.2% above 2011, reflecting a continued growing trend in these emissions, GATM was 5.1 ± 0.2 GtC yr-1, SOCEAN was 2.9 ± 0.5 GtC yr-1, and assuming an ELUC of 1.0 ± 0.5 GtC yr-1 (based on the 2001-2010 average), SLAND was 2.7 ± 0.9 GtC yr-1. GATM was high in 2012 compared to the 2003-2012 average, almost entirely reflecting the high EFF. The global atmospheric CO2 concentration reached 392.52 ± 0.10 ppm averaged over 2012. We estimate that EFF will increase by 2.1% (1.1-3.1%) to 9.9 ± 0.5 GtC in 2013, 61% above emissions in 1990, based on projections of world gross domestic product and recent changes in the carbon intensity of the economy. With this projection, cumulative emissions of CO2 will reach about 535 ± 55 GtC for 1870-2013, about 70% from EFF (390 ± 20 GtC) and 30% from ELUC (145 ± 50 GtC). This paper also documents any changes in the methods and data sets used in this new carbon budget from previous budgets (Le Quéré et al., 2013). All observations presented here can be downloaded from the Carbon Dioxide Information Analysis Center (doi:10.3334/CDIAC/GCP_2013_V2.3).

Le Quéré, C.; Peters, G. P.; Andres, R. J.; Andrew, R. M.; Boden, T. A.; Ciais, P.; Friedlingstein, P.; Houghton, R. A.; Marland, G.; Moriarty, R.; Sitch, S.; Tans, P.; Arneth, A.; Arvanitis, A.; Bakker, D. C. E.; Bopp, L.; Canadell, J. G.; Chini, L. P.; Doney, S. C.; Harper, A.; Harris, I.; House, J. I.; Jain, A. K.; Jones, S. D.; Kato, E.; Keeling, R. F.; Klein Goldewijk, K.; Körtzinger, A.; Koven, C.; Lefèvre, N.; Maignan, F.; Omar, A.; Ono, T.; Park, G.-H.; Pfeil, B.; Poulter, B.; Raupach, M. R.; Regnier, P.; Rödenbeck, C.; Saito, S.; Schwinger, J.; Segschneider, J.; Stocker, B. D.; Takahashi, T.; Tilbrook, B.; van Heuven, S.; Viovy, N.; Wanninkhof, R.; Wiltshire, A.; Zaehle, S.

2014-06-01

282

Studies and characterisations of various activated carbons used for carbon/carbon supercapacitors  

NASA Astrophysics Data System (ADS)

Various activated carbons from the PICA Company have been tested in supercapacitor cells in order to compare their performances. The differences measured in terms of specific capacitance and cell resistance are presented. Porosity measurements made on activated carbon powders and electrode allowed a better understanding of the electrochemical behaviour of these activated carbons. In this way, the PICACTIF SC carbon was found to be an interesting active material for supercapacitors, with a specific capacitance as high as 125 F/g.

Gamby, J.; Taberna, P. L.; Simon, P.; Fauvarque, J. F.; Chesneau, M.

283

Modeling the geochemical carbon cycle  

SciTech Connect

The authors have modeled the slow, long-term cycle in which geochemical processes transfer carbon among land, sea, and atmosphere. The model suggests that the earth may have been warmed in the past when buildups of atmospheric carbon dioxide enhanced the greenhouse effect. The model predicts that the slow natural fluctuations of atmospheric carbon dioxide may rival or even exceed the much faster changes that arise from human activities or from the biological carbon cycle. The main purpose in modeling the geochemical carbon cycle is to expose how little is known about the rates of important global processes and how seemingly unrelated processes (such as tectonism and climate) are linked.

Berner, R.A.; Lasaga, A.C.

1989-03-01

284

Carbon Capture and Storage, 2008  

SciTech Connect

The U.S. Department of Energy is researching the safe implementation of a technology called carbon sequestration, also known as carbon capture and storage, or CCS. Based on an oilfield practice, this approach stores carbon dioxide, or CO2 generated from human activities for millennia as a means to mitigate global climate change. In 2003, the Department of Energys National Energy Technology Laboratory formed seven Regional Carbon Sequestration Partnerships to assess geologic formations suitable for storage and to determine the best approaches to implement carbon sequestration in each region. This video describes the work of these partnerships.

2009-03-19

285

Carbon dioxide dangers demonstration model  

USGS Publications Warehouse

Carbon dioxide is a dangerous volcanic gas. When carbon dioxide seeps from the ground, it normally mixes with the air and dissipates rapidly. However, because carbon dioxide gas is heavier than air, it can collect in snowbanks, depressions, and poorly ventilated enclosures posing a potential danger to people and other living things. In this experiment we show how carbon dioxide gas displaces oxygen as it collects in low-lying areas. When carbon dioxide, created by mixing vinegar and baking soda, is added to a bowl with candles of different heights, the flames are extinguished as if by magic.

Venezky, Dina; Wessells, Stephen

2010-01-01

286

Understanding the Global Carbon Cycle  

NSDL National Science Digital Library

The site offers charts and graphs to aid in a detailed explanation of where carbon comes from and where it goes. Supplementing the main topic, links lead to the topics Carbon and Land Use, Missing Carbon Sink, and Forest Sequestered Carbon Dioxide. Their conclusion is that the major contributor to climatic change, and hence the human activity most in need of change, is use of fossil fuels for energy. Advances in the technology of renewable energy sources, including wood-derived fuels, might reduce our reliance on fossil fuels and thus reduce global emissions of carbon dioxide significantly.

287

Carbon solubility in mantle minerals  

NASA Astrophysics Data System (ADS)

The solubility of carbon in olivine, enstatite, diopside, pyrope, MgAl 2O 4 spinel, wadsleyite, ringwoodite, MgSiO 3-ilmenite and MgSiO 3-perovskite has been quantified. Carbon-saturated crystals were grown from carbonatite melts at 900-1400 °C and 1.5 to ˜ 26 GPa in piston cylinder or multi-anvil presses using carbon enriched to > 99% in the 13C isotope. In upper mantle silicates, carbon solubility increases as a function of pressure to a maximum of ˜ 12 ppm by weight in olivine at 11 GPa. No clear dependence of carbon solubility on temperature, oxygen fugacity or iron content was observed. The observation that carbon solubility in olivine is insensitive to oxygen fugacity implies that the oxidation state of carbon in the carbonatite melt and in olivine is the same, i.e., carbon dissolves as C 4+ in olivine. Carbon solubility in spinel MgAl 2O 4, transition zone minerals (wadsleyite and ringwoodite), MgSiO 3-ilmenite and MgSiO 3-perovskite are below the limit of detection of our SIMS-based analytical technique (i.e., below 30-200 ppb by weight). The differences in carbon solubilities between the various minerals studied appear to correlate with the polyhedral volume of the Si 4+ site, consistent with a direct substitution of C 4+ for Si 4+. These results show that other, minor carbon-rich phases, rather than major, nominally volatile-free minerals, dominate the carbon budget within the bulk Earth's mantle. A significant fraction of total carbon could only be stored in silicates in a thin zone in the lowermost upper mantle, just above the transition zone, and only if the bulk carbon content is at the lower limit of published estimates. The carbon budget of the remaining mantle is dominated by carbonates and possibly diamond. The low melting point of carbonates and the high mobility of carbonate melts suggest that carbon distribution in the mantle may be highly heterogeneous, including the possibility of massive carbon enrichments on a local scale, particularly in the shallow subcontinental mantle.

Shcheka, Svyatoslav S.; Wiedenbeck, Michael; Frost, Daniel J.; Keppler, Hans

2006-05-01

288

Carbon Capture and Storage, 2008  

ScienceCinema

The U.S. Department of Energy is researching the safe implementation of a technology called carbon sequestration, also known as carbon capture and storage, or CCS. Based on an oilfield practice, this approach stores carbon dioxide, or CO2 generated from human activities for millennia as a means to mitigate global climate change. In 2003, the Department of Energys National Energy Technology Laboratory formed seven Regional Carbon Sequestration Partnerships to assess geologic formations suitable for storage and to determine the best approaches to implement carbon sequestration in each region. This video describes the work of these partnerships.

None

2010-01-08

289

Carbon materials for supercapacitors  

NASA Astrophysics Data System (ADS)

As an important energy storage device, electrochemical supercapacitors or ultracapacitors fill the gap between conventional dielectric capacitors and batteries in terms of specific energy and power. Although supercapacitors have been used in electric vehicles, digital communication instruments, and pulsed lasers, further improvement of supercapacitor performance is highly needed to enhance the energy density without significantly losing the power density. Additionally, the conventional supercapacitors use rigid packages and liquid electrolytes, which limit applications in transparent and flexible electronics. To address these challenges, the research efforts in this dissertation mainly focused on: 1) improvement of the energy density of carbon nanoonions by chemical activation; 2) laser-assisted activation of carbon nanotubes for improved energy density; 3) fabrication of flexible solid-state supercapacitors based on nanocarbon and manganese dioxide (MnO2) hybrid electrodes; and 4) investigation of the electrochemical performance of graphene as transparent and flexible supercapacitor electrodes.

Gao, Yang

290

California's Future Carbon Flux  

NASA Astrophysics Data System (ADS)

The diversity of the climate and vegetation systems in the state of California provides a unique opportunity to study carton dioxide exchange between the terrestrial biosphere and the atmosphere. In order to accurately calculate the carbon flux, this study couples the sophisticated analytical surface layer model ACASA (Advance Canopy-Atmosphere-Soil Algorithm, developed in the University of California, Davis) with the newest version of mesoscale model WRF (the Weather Research & Forecasting Model, developed by NCAR and several other agencies). As a multilayer, steady state model, ACASA incorporates higher-order representations of vertical temperature variations, CO2 concentration, radiation, wind speed, turbulent statistics, and plant physiology. The WRF-ACASA coupling is designed to identify how multiple environmental factors, in particularly climate variability, population density, and vegetation distribution, impact on future carbon cycle prediction across a wide geographical range such as in California.

Xu, L.; Pyles, R. D.; Paw U, K.; Gertz, M.

2008-12-01

291

The colloidal stabilization of carbon with carbon: carbon nanobubbles as both dispersant and glue for carbon nanotubes.  

PubMed

The superior physical properties of carbon nanotubes (CNTs) have led to their broad application. Intrinsically, CNTs tend to agglomerate from hydrophobic interactions, which is highly undesirable for solution processing and device fabrication. Commonly, a stabilizer consisting of organic surfactants or polymers is used to disperse CNTs. Recently, we synthesized nitrogen-doped carbon hollow nanospheres (25-90?nm), termed carbon "nanobubbles". They bear superior dispersability in water and distinctive graphitic order. Herein, we describe the nanobubble-assisted dispersion of CNTs in aqueous solution upon sonication. This process relies on the ?-? interaction between the two aromatic carbon nanostructures, which can process their carbon mixture in water into conductive filter membranes, ink, and discs. This stabilization can be extended to other aromatic carbons. In addition, the ?-? interaction may create a new type of carbon p-n junction that can be used to improve charge separation. PMID:24311464

Kuzmicz, Danuta; Prescher, Simon; Polzer, Frank; Soll, Sebastian; Seitz, Christoph; Antonietti, Markus; Yuan, Jiayin

2014-01-20

292

Carbon Nanotubes Toxicity  

NASA Astrophysics Data System (ADS)

We describe current and possible future developments in nanotechnology for biological and medical applications. Nanostructured, composite materials for drug delivery, biosensors, diagnostics and tumor therapy are reviewed as examples, placing special emphasis on silica composites. Carbon nanotubes are discussed as a primary example of emerging nanomaterials for many of the above-mentioned applications. Toxicity effects of this novel nanomaterial are discussed and the need for further study of potential hazards for human health, professionally exposed workers and the environment is motivated.

Bellucci, Stefano

293

Carbon nanotube intramolecular junctions  

Microsoft Academic Search

The ultimate device miniaturization would be to use individual molecules as functional devices. Single-wall carbon nanotubes (SWNTs) are promising candidates for achieving this: depending on their diameter and chirality, they are either one-dimensional metals or semiconductors. Single-electron transistors employing metallic nanotubes and field-effect transistors employing semiconducting nanotubes have been demonstrated. Intramolecular devices have also been proposed which should display a

Zhen Yao; Henk W. Ch. Postma; Leon Balents; Cees Dekker

1999-01-01

294

The Carbon Cycle  

NSDL National Science Digital Library

This online lab exercise focuses on the processes involved in the Carbon cycle and the influences of human activity on those processes- especially as they relate to Earth's weather and climate. The fourth in a 10-part lab series on weather and climate, this lab exercise is designed for first and second year college geoscience students (majors and non-majors) as well as pre-service STEM teachers.

295

Carbonate platform facies models  

SciTech Connect

Various types of carbonate platforms are characterized by distinctive profiles, facies, and evolutionary sequences. Ramps may be homoclinal or distally steepened, and may have fringing or barrier shoal-water complexes of ooidpellet sands or skeletal banks. These platforms change in response to variations in sedimentation, subsidence or sea level rise, and may form distinctive evolutionary sequences. The relatively few models presented appear to accommodate most geological examples, some of which contain major reservoir facies. 10 figures.

Read, J.F.

1985-12-01

296

Amorphous Carbon Nanospheres  

SciTech Connect

Amorphous carbon nanosphere used as the anode material for Li-intercalation in Lithium-ion energy storage. This structure was obtained through a thermal annealing process at a temperature of 3000 degree Kelvin, simulated using the LAMMPS molecular dynamics code on the LCRC Fusion resource. Science: Kah Chun Lau, Larry Curtiss, Argonne National Laboratory Visualization: Aaron Knoll, Mark Hereld, Michael E. Papka, Argonne National Laboratory

None

2012-01-01

297

Modeling Carbon Dioxide Levels  

NSDL National Science Digital Library

In this activity students will explore levels of Carbon Dioxide ( C02) in the atmosphere over time. There is concern that levels of C02 are rising; and finding a good mathematical model for CO2 levels is an important part of determining if this is attributable to human technology. Students draw a scatter plot, choose two points to create a linear model for the data, then use the model to make predictions.

2009-01-01

298

Carbonate fuel cell matrix  

DOEpatents

A carbonate fuel cell matrix comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles.

Farooque, Mohammad (Huntington, CT) [Huntington, CT; Yuh, Chao-Yi (New Milford, CT) [New Milford, CT

1996-01-01

299

Carbonate fuel cell matrix  

DOEpatents

A carbonate fuel cell matrix is described comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles. 8 figs.

Farooque, M.; Yuh, C.Y.

1996-12-03

300

Carbon Dioxide Capture and Disposal  

NASA Astrophysics Data System (ADS)

Unless carbon dioxide from fossil fuel combustion is captured and disposed of safely and permanently, the concerns over climate change will eventually lead to the demise of fossil fuels. Because of their importance in today's energy market the phasing out of fossil fuels would likely precipitate a major energy crisis. Mineral sequestration and extraction of carbon dioxide from the air are two advanced technologies for carbon sequestration that aim at maintaining access to the vast fossil energy resources for centuries to come. While it is straightforward to dispose of carbon dioxide in limited amounts and for a limited time, permanent disposal of trillions of tons of carbon poses serious challenges. The formation of solid mineral carbonates from readily available minerals would provide safe and permanent storage. Capture of carbon dioxide from air makes it possible to sequester carbon dioxide emissions from sources other than power plants. This is important considering that even the relatively minor reductions suggested by the Kyoto Accord would have required the US to eliminate carbon dioxide emissions comparable to those of the entire 1990 coal fired power plant fleet. Capture of carbon dioxide from the air, would make it possible to close the carbon cycle in the transportation sector without phasing out liquid hydrocarbon fuels. It eliminates the need for long distance transport of carbon dioxide and allows the continued use of the existing energy infrastructure. Mineral sequestration at remote sites combined with on site carbon dioxide capture from air, would allow for long term stabilization of atmospheric carbon dioxide levels. I will outline the current state of the technology and point to advances required before these approaches are ready for large-scale implementation.

Lackner, K. S.

2002-05-01

301

Interfaces of propylene carbonate  

NASA Astrophysics Data System (ADS)

Propylene carbonate (PC) wets graphite with a contact angle of 31° at ambient conditions. Molecular dynamics simulations agree with this contact angle after 40% reduction of the strength of graphite-C atom Lennard-Jones interactions with the solvent, relative to the models used initially. A simulated nano-scale PC droplet on graphite displays a pronounced layering tendency and an Aztex pyramid structure for the droplet. Extrapolation of the computed tensions of PC liquid-vapor interface estimates the critical temperature of PC accurately to about 3%. PC molecules lie flat on the PC liquid-vapor surface and tend to project the propyl carbon toward the vapor phase. For close PC neighbors in liquid PC, an important packing motif stacks carbonate planes with the outer oxygen of one molecule snuggled into the positively charged propyl end of another molecule so that neighboring molecule dipole moments are approximately antiparallel. The calculated thermal expansion coefficient and the dielectric constants for liquid PC agree well with experiment. The distribution of PC molecule binding energies is closely Gaussian. Evaluation of the density of the coexisting vapor then permits estimation of the packing contribution to the PC chemical potential and that contribution is about two thirds of the magnitude of the contributions due to attractive interactions, with opposite sign.

You, Xinli; Chaudhari, Mangesh I.; Pratt, Lawrence R.; Pesika, Noshir; Aritakula, Kalika M.; Rick, Steven W.

2013-03-01

302

Interfaces of propylene carbonate.  

PubMed

Propylene carbonate (PC) wets graphite with a contact angle of 31° at ambient conditions. Molecular dynamics simulations agree with this contact angle after 40% reduction of the strength of graphite-C atom Lennard-Jones interactions with the solvent, relative to the models used initially. A simulated nano-scale PC droplet on graphite displays a pronounced layering tendency and an Aztex pyramid structure for the droplet. Extrapolation of the computed tensions of PC liquid-vapor interface estimates the critical temperature of PC accurately to about 3%. PC molecules lie flat on the PC liquid-vapor surface and tend to project the propyl carbon toward the vapor phase. For close PC neighbors in liquid PC, an important packing motif stacks carbonate planes with the outer oxygen of one molecule snuggled into the positively charged propyl end of another molecule so that neighboring molecule dipole moments are approximately antiparallel. The calculated thermal expansion coefficient and the dielectric constants for liquid PC agree well with experiment. The distribution of PC molecule binding energies is closely Gaussian. Evaluation of the density of the coexisting vapor then permits estimation of the packing contribution to the PC chemical potential and that contribution is about two thirds of the magnitude of the contributions due to attractive interactions, with opposite sign. PMID:23534654

You, Xinli; Chaudhari, Mangesh I; Pratt, Lawrence R; Pesika, Noshir; Aritakula, Kalika M; Rick, Steven W

2013-03-21

303

Studies of Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

The fellowship experience for this summer for 2004 pertains to carbon nanotube coatings for various space-related applications. They involve the following projects: (a) EMI protection films from HiPco-polymers, and (b) Thermal protection nanosilica materials. EMI protection films are targeted to be eventually applied onto casings of laptop computers. These coatings are composites of electrically-conductive SWNTs and compatible polymers. The substrate polymer will be polycarbonate, since computer housings are typically made of carbon composites of this type of polymer. A new experimental copolymer was used last year to generate electrically-conductive and thermal films with HiPco at 50/50 wt/wt composition. This will be one of the possible formulations. Reference films will be base polycarbonate and neat HiPco onto polycarbonate films. Other coating materials that will be tried will be based on HiPco composites with commercial enamels (polyurethane, acrylic, polyester), which could be compatible with the polycarbonate substrate. Nanosilica fibers are planned for possible use as thermal protection tiles on the shuttle orbiter. Right now, microscale silica is used. Going to the nanoscale will increase the surface-volume-per-unit-area of radiative heat dissipation. Nanoscale carbon fibers/nanotubes can be used as templates for the generation of nanosilica. A sol-gel operation is employed for this purpose.

Caneba, Gerard T.

2005-01-01

304

Oxidation of Carbon/Carbon through Coating Cracks  

NASA Technical Reports Server (NTRS)

Reinforced carbon/carbon (RCC) is used to protect the wing leading edge and nose cap of the Space Shuttle Orbiter on re-entry. It is composed of a lay-up of carbon/carbon fabric protected by a SiC conversion coating. Due to the thermal expansion mismatch of the carbon/carbon and the SiC, the SiC cracks on cool-down from the processing temperature. The cracks act as pathways for oxidation of the carbon/carbon. A model for the diffusion controlled oxidation of carbon/carbon through machined slots and cracks is developed and compared to laboratory experiments. A symmetric cylindrical oxidation cavity develops under the slots, confirming diffusion control. Comparison of cross sectional dimensions as a function of oxidation time shows good agreement with the model. A second set of oxidation experiments was done with samples with only the natural craze cracks, using weight loss as an index of oxidation. The agreement of these rates with the model is quite reasonab

Jacobson, N. S.; Roth, d. J.; Rauser, R. W.; Cawley, J. D.; Curry, D. M.

2008-01-01

305

The effect of carbonization temperature of PAN fiber on the properties of activated carbon fiber composites  

Microsoft Academic Search

The PAN (polyacrylonitrile) based carbon fiber composites were prepared from mixtures of chopped carbon fibers and phenolic resin. Two different carbon fibers were obtained by carbonization of stabilized PAN fiber precursors in nitrogen at 1073 and 1273 K, respectively. Samples of activated carbon fiber composites (ACFCs) were prepared from the carbon fiber composites by activation in carbon dioxide at 1123

J. C. Lee; B. H. Lee; B. G. Kim; M. J. Park; D. Y. Lee; I. H. Kuk; H. Chung; H. S. Kang; H. S. Lee; D. H. Ahn

1997-01-01

306

Catalytic carbon deposition on three-dimensional carbon fiber preforms using alkane gas feedstocks  

Microsoft Academic Search

The rate of carbon deposition and the carbon nanostructures formed during the chemical vapor deposition of ethane and synthetic natural gas, with and without added hydrogen, over a nickel catalyst, supported on three-dimensional (3D) carbon fiber preforms, was investigated. Graphitic nanofibers, carbon nanotubes, and graphitic carbon shells were observed following carbon deposition; the nanostructured carbon deposited was dependant on deposition

Matthew J Thornton; Gavin S Walker

2009-01-01

307

Thermal Cycling of Thermal Control Paints on Carbon-Carbon and Carbon-Polyimide Composites  

NASA Technical Reports Server (NTRS)

Carbon-carbon composites and carbon-polyimide composites are being considered for space radiator applications owing to their light weight and high thermal conductivity. For those radiator applications where sunlight will impinge on the surface, it will be necessary to apply a white thermal control paint to minimize solar absorptance and enhance infrared emittance. Several currently available white thermal control paints were applied to candidate carbon-carbon and carbon-polyimide composites and were subjected to vacuum thermal cycling in the range of -100 C to +277 C. The optical properties of solar absorptance and infrared emittance were evaluated before and after thermal cycling. In addition, adhesion of the paints was evaluated utilizing a tape test. The test matrix included three composites: resin-derived carbon-carbon and vapor infiltrated carbon-carbon, both reinforced with pitch-based P-120 graphite fibers, and a polyimide composite reinforced with T-650 carbon fibers, and three commercially available white thermal control paints: AZ-93, Z-93-C55, and YB-71P.

Jaworske, Donald A.

2006-01-01

308

Lowstand carbonates, highstand sandstones?  

NASA Astrophysics Data System (ADS)

The sedimentary facies, sediment dynamics and sequence architecture of modern high-energy shelves in the mid and high latitudes are largely governed by wave abrasion processes. Cool-water carbonates may form there, if the influx and/or net accretion of siliciclastics is kept at a minimum. Little dilution of the carbonate produced in situ is generally promoted by a wide "epicontinental" shelf, subdued topography of the adjacent mainland, the predominance of limestone outcrops, and an arid climate. The aforementioned requirements are rarely met, and thus will automatically lead to the formation of mixed siliciclastic-cool-water carbonates. Such an example is found in the Early to Mid-Miocene Lagos-Portimão Formation (Algarve, S-Portugal), which formed on a narrow high-energy shelf of the Atlantic Ocean that was bounded by a mountain range. The sediments of the formation consist of fossiliferous sandstone (FS), shell beds, and rhodolith blankets. Along strike, the stratification of the formation is monotonous for tens of kilometres and well exposed in coastal cliffs, whereas no outcrops of dip sections exist. The bulk skeletal composition of the sediments is typical for the warm-temperate climatic zone: various endo- and epibenthic bivalves, bryozoans, coralline algae, echinoderms, gastropods, and large foraminifers ( Heterostegina). In some very rare beds, a few isolated, not framework-forming specimens of zooxanthellate corals ( Porites, Tarbellastrea) indicate temporally elevated surface water temperatures close to the lower threshold of the coral reef ecosystem. In sandstones, the fauna is well preserved and burrowing bivalves are commonly found in life position. In limestone beds, the state of preservation of the grains ranges from intact to disintegrated and abraded specimens. We infer an accumulation of the shell beds through winnowing of fine materials (siliciclastic sand and carbonate mud) at wave abrasion depth and concentration of calcareous skeletons associated with the subsequent attraction of new epibiota in a complex shell bed. The vertical alternation of fossiliferous sandstone and shell beds, and in-phase variations of the "Photo Index" (photic biota vs. bryozoans) and "Bryozoan Index" (bivalves vs. bryozoans) is envisaged to document variations of water depth (and sea level). Sandstone units built up when wave abrasion depth (WAD) rose above the sea floor during TST (and early HST), whereas the shell beds formed during LST when the WAD for sand intersected with the sea floor. Clastic sediments were probably brought on the outer shelf during early transgression, and by longshore currents. Sea-level signatures inferred in the mixed siliciclastic-cool-water carbonate shelf setting of S-Portugal therefore significantly deviate from conventional concepts of carbonate sequence stratigraphy, which were developed for flat-topped platforms. Successful interpretations of ancient mixed sequences must therefore take into consideration the processes of production, concentration and accretion of the carbonate sediments.

Brachert, T. C.; Forst, M. H.; Pais, J. J.; Legoinha, P.; Reijmer, J. J. G.

2003-01-01

309

An advanced carbon reactor subsystem for carbon dioxide reduction  

NASA Technical Reports Server (NTRS)

An evaluation is presented of the development status of an advanced carbon-reactor subsystem (ACRS) for the production of water and dense, solid carbon from CO2 and hydrogen, as required in physiochemical air revitalization systems for long-duration manned space missions. The ACRS consists of a Sabatier Methanation Reactor (SMR) that reduces CO2 with hydrogen to form methane and water, a gas-liquid separator to remove product water from the methane, and a Carbon Formation Reactor (CFR) to pyrolize methane to carbon and hydrogen; the carbon is recycled to the SMR, while the produce carbon is periodically removed from the CFR. A preprototype ACRS under development for the NASA Space Station is described.

Noyes, Gary P.; Cusick, Robert J.

1986-01-01

310

A look at carbonate rocks  

SciTech Connect

Important ore deposits are found in carbonate rocks, and large volumes of oil and gas are also produced from carbonate rocks on a worldwide basis. Reservoir types and productive capability are most often related to rock type and the facies to which the rock belongs. Broad new understanding of carbonate rocks came with the publication of Classification of Carbonate Rocks-A Symposium (AAPG Memoir 1, 1962). The principal parameters of carbonate rocks are (1) chemical composition, (2) grade size, (3) sorting and packing, (4) identification of grains in the rock, (5) cement, (6) color, (7) alteration of recrystallization, and (8) porosity. Original porosity in carbonate rocks relates to kind and packing of original particles. Secondary porosity is reduced by infilling that usually relates to some particles, or is enhanced because some types of grains are dissolved. Carbonate sediments are organic detritus. The range of solubility of organic detritus is very large. Fossils present in the carbonates are clues as to the source of the detritus in the rock. Additional research is needed in faunal relations of facies and of rock types. Ore recovery, well completion, and EOR are more successful when the parameters of carbonate rocks are extensively studied. A simplified approach to carbonate description is discussed.

Bowsher, A.I. (Independent Geologist, Roswell, NM (United States))

1994-03-01

311

Carbon dioxide sequestration by ex-situ mineral carbonation  

Microsoft Academic Search

The process developed for carbon dioxide sequestration utilizes a slurry of water mixed with olivine- forsterite end member (MgâSiOâ), which is reacted with supercritical COâ to produce magnesite (MgCOâ). Carbon dioxide is dissolved in water to form carbonic acid, which likely dissociates to H{sup +} and HCOâ⁻. The H{sup +} hydrolyzes the silicate mineral, freeing the cation (Mg{sup 2+}), which

W. K. OConnor; D. C. Dahlin; P. C. Turner

2000-01-01

312

From Vapor-Grown Carbon Fibers (Vgcfs) To Carbon Nanotubes  

Microsoft Academic Search

\\u000a Careful growth control during chemical vapor deposition makes it possible to obtain various morphologies of carbon fibers:\\u000a from normal vapor-grown carbon fibers (VGCFs) through submicron VGCFs to nanofibers or carbon nanotubes. The combined effects\\u000a of excellent physical properties and low production costs have spurred applications research for these fibers in various fields.

M. Endo; Y. A. Kim; T. Matusita; T. Hayashi

313

Inhibition of catalytic oxidation of carbon\\/carbon composite materials  

Microsoft Academic Search

An investigation coupling experimental efforts with computational chemistry analysis was conducted to study the inhibition effects of phosphorous or boron on the oxidation of carbon\\/carbon composite materials catalyzed by potassium or calcium acetate (KAC or CaAC). Commercial aircraft brakes were used, which are exposed during use to K- or Ca-containing runway deicing agents. The reactivity of inhibitor-doped carbon materials was

Xianxian Wu

2002-01-01

314

Alternative cathodes for molten carbonate fuel cells  

SciTech Connect

Yttrium Ions Garnets (YIG), Y{sub 3}Fe{sub 5}O{sub 12}, and Barium Ferrite, BaFe{sub 12}O{sub 19}, were synthesized and characterized. Among the various synthesis techniques tried the gel resin process was found to be the best method of synthesis in terms of purity of the phase and the conventional powder mixing/calcination technique was found to give the highest yield of the desired phase in larger quantities. Doping and calcining conditions were established to synthesize phase pure Ca-doped cubic YIG. The weight loss of doped YIG in molten carbonate was comparable to that reported for NiO, the current state-of-the-art cathode material. However, the stability of the YIG is expected to be better than NiO due to the stability of the corrosion product, Y{sub 2}O{sub 3}. The performance of doped YIG cathode in an in-cell test at the Institute of Gas Technology was below the present state of the are cathode due to high polarization loss. A Barium Ferrite based magnetoplumbite material was tested as a potential cathode candidate in molten carbonate. The material formed a reaction product that was conductive at room temperature; it also exhibited some magnetization.

Rolfson, B.K.; Elangovan, S.; Khandkar, A.C. (Ceramatec, Inc., Salt Lake City, UT (USA))

1990-05-01

315

Geologic Carbon Sequestration and Biosequestration (Carbon Cycle 2.0)  

ScienceCinema

Don DePaolo, Director of LBNL's Earth Sciences Division, speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 3, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

316

Method for joining carbon-carbon composites to metals  

DOEpatents

A method for joining carbon-carbon composites to metals by brazing. Conventional brazing of recently developed carbon-bonded carbon fiber (CBCF) material to a metal substrate is limited by the tendency of the braze alloy to ``wick`` into the CBCF composite rather than to form a strong bond. The surface of the CBCF composite that is to be bonded is first sealed with a fairly dense carbonaceous layer achieved by any of several methods. The sealed surface is then brazed to the metal substrate by vacuum brazing with a Ti-Cu-Be alloy. 1 fig.

Lauf, R.J.; McMillan, A.D.; Moorhead, A.J.

1997-07-15

317

Novel carbon-carbon bond formations for biocatalysis  

PubMed Central

Carbon–carbon bond formation is the key transformation in organic synthesis to set up the carbon backbone of organic molecules. However, only a limited number of enzymatic C–C bond forming reactions have been applied in biocatalytic organic synthesis. Recently, further name reactions have been accomplished for the first time employing enzymes on a preparative scale, for instance the Stetter and Pictet–Spengler reaction or oxidative C–C bond formation. Furthermore, novel enzymatic C–C bond forming reactions have been identified like benzylation of aromatics, intermolecular Diels-Alder or reductive coupling of carbon monoxide.

Resch, Verena; Schrittwieser, Joerg H; Siirola, Elina; Kroutil, Wolfgang

2011-01-01

318

Method for joining carbon-carbon composites to metals  

DOEpatents

A method for joining carbon-carbon composites to metals by brazing. Conventional brazing of recently developed carbon-bonded carbon fiber (CBCF) material to a metal substrate is limited by the tendency of the braze alloy to "wick" into the CBCF composite rather than to form a strong bond. The surface of the CBCF composite that is to be bonded is first sealed with a fairly dense carbonaceous layer achieved by any of several methods. The sealed surface is then brazed to the metal substrate by vacuum brazing with a Ti-Cu-Be alloy.

Lauf, Robert J. (Oak Ridge, TN); McMillan, April D. (Knoxville, TN); Moorhead, Arthur J. (Knoxville, TN)

1997-01-01

319

Carbon Nanotube-Enhanced Carbon-Phenenolic Ablator Material  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews the use of PICA (phenolic impregnated carbon ablator) as the selected material for heat shielding for future earth return vehicles. It briefly reviews the manufacturing of PICA and the advantages for the use of heat shielding, and then explains the reason for using Carbon Nanotubes to improve strength of phenolic resin that binds carbon fibers together. It reviews the work being done to create a carbon nanotube enhanced PICA. Also shown are various micrographic images of the various PICA materials.

Kikolaev, P.; Stackpoole, M.; Fan, W.; Cruden, B. A.; Waid, M.; Moloney, P.; Arepalli, S.; Arnold, J.; Partridge, H.; Yowell, L.

2006-01-01

320

Carbon-hydrogen bonding in near-frictionless carbon.  

SciTech Connect

The uniquely low friction behavior of near-frictionless carbon (NFC) as compared to conventional diamondlike carbon (DLC) is determined by the bonding within the film. Inelastic neutron scattering (INS) and Fourier transform infrared (FTIR) spectroscopy were used to probe the bonding environment of carbon and hydrogen; both INS and FTIR can probe the whole sample. Previous work has focused on surface studies; the present results show that in the film as a whole the majority of the hydrogen is adjacent to sp{sup 3}-bonded carbon. In addition this work has determined the absence of any molecular hydrogen in NFC.

Johnson, J. A.; Woodford, J. B.; Rajput, D.; Kolesnikov, A. I.; Schleuter, J. A.; Eryilmaz, O. L.; Erdemir, A.; Univ. of Tennessee Space Inst.; ORNL

2008-01-01

321

Carbon-hydrogen bonding in near-frictionless carbon  

NASA Astrophysics Data System (ADS)

The uniquely low friction behavior of near-frictionless carbon (NFC) as compared to conventional diamondlike carbon (DLC) is determined by the bonding within the film. Inelastic neutron scattering (INS) and Fourier transform infrared (FTIR) spectroscopy were used to probe the bonding environment of carbon and hydrogen; both INS and FTIR can probe the whole sample. Previous work has focused on surface studies; the present results show that in the film as a whole the majority of the hydrogen is adjacent to sp3-bonded carbon. In addition this work has determined the absence of any molecular hydrogen in NFC.

Johnson, J. A.; Woodford, J. B.; Rajput, D.; Kolesnikov, A. I.; Schleuter, J. A.; Eryilmaz, O. L.; Erdemir, A.

2008-09-01

322

Carbon-hydrogen bonding in near-frictionless carbon  

SciTech Connect

The uniquely low friction behavior of near frictionless carbon (NFC) as compared to conventional diamond-like carbon (DLC) is determined by the bonding within the film. Inelastic neutron scattering (INS) and Fourier Transform Infrared (FTIR) spectroscopy were used to probe the bonding environment of carbon and hydrogen; both INS and FTIR can probe the whole sample. Previous work has focused on surface studies; the present results show that in the film as a whole the majority of the hydrogen is adjacent to sp3-bonded carbon. In addition this work has determined the absence of any molecular hydrogen in NFC.

Johnson, Jackie A. [University of Tennessee Space Institute; Woodford, John B [Argonne National Laboratory (ANL); Rajput, Deepak [University of Tennessee Space Institute; Kolesnikov, Alexander I [ORNL; Schleuter, John A [Argonne National Laboratory (ANL); Eryilmaz, Osman L [Argonne National Laboratory (ANL); Erdemir, Ali [Argonne National Laboratory (ANL)

2008-01-01

323

Geologic Carbon Sequestration and Biosequestration (Carbon Cycle 2.0)  

ScienceCinema

Don DePaolo, Director of LBNL's Earth Sciences Division, speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 3, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

DePaolo, Don [Director, LBNL Earth Sciences Division

2011-06-08

324

Soil warming, carbon-nitrogen interactions, and forest carbon budgets.  

PubMed

Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observed increases in plant carbon storage. Although soil warming has resulted in a cumulative net loss of carbon from a New England forest relative to a control area over the 7-y study, the annual net losses generally decreased over time as plant carbon storage increased. In the seventh year, warming-induced soil carbon losses were almost totally compensated for by plant carbon gains in response to warming. We attribute the plant gains primarily to warming-induced increases in nitrogen availability. This study underscores the importance of incorporating carbon-nitrogen interactions in atmosphere-ocean-land earth system models to accurately simulate land feedbacks to the climate system. PMID:21606374

Melillo, Jerry M; Butler, Sarah; Johnson, Jennifer; Mohan, Jacqueline; Steudler, Paul; Lux, Heidi; Burrows, Elizabeth; Bowles, Francis; Smith, Rose; Scott, Lindsay; Vario, Chelsea; Hill, Troy; Burton, Andrew; Zhou, Yu-Mei; Tang, Jim

2011-06-01

325

Carbonate ramp depositional systems  

NASA Astrophysics Data System (ADS)

The classification, tectonic settings, stratigraphy and early diagenesis of carbonate ramp systems are reviewed. Carbonate ramps are common in all geological periods, but were dominant at times when reef-constructing organisms were absent or inhibited. Ramps can be subdivided into inner-, mid-, and outer-ramp environments. The mid-ramp zone extends from fair-weather wave base to normal storm wave base, although the water depths which these boundaries represent vary. An additional outer-slope environment occurs on distally steepened ramps. As with siliciclastic shelves, a range of wave-, storm-, and tide-dominated ramps can be recognised and this forms the most convenient basis for ramp classification. The carbonate productivity profile of ramps differs from that of rimmed shelves, with the inner ramp showing lower production rates than comparable shallow-water facies on rimmed shelves. The zone of greatest organic carbonate sediment production appears to have shifted from the mid-ramp to the inner ramp since the Late Jurassic. Carbonate ramps occur in most types of sedimentary basin but are best developed where subsidence is flexural and gradients are slight over large areas, as in foreland and cratonic-interior basins and along passive margins. The featureless depositional profiles of many ramps means that sequence geometries are best observed on regional seismic lines. Some show low-angle sigmoidal or shingled clinoforms, suggesting that ramps may seldom be "homoclinal", but possess subtle slope geometries which reflect depositional environments. Because of their low-angle slopes, ramps respond differently to rimmed shelves during relative sea-level changes although results seem to be strongly dependent on the rate of relative sea-level change. During a minor fall, shallow-ramp facies belts will simply shift basinwards in a "forced regression". In contrast, the whole surface of a steep-sloped, flat-topped rimmed shelf may be exposed so that sediment production ceases or is drastically reduced. During a major fall, shallow ramp-bounded basins may empty completely. Conversely, ramps also flood gradually, whereas rimmed shelves do so more rapidly. Homoclinal ramps develop no resedimented lowstand deposits; rimmed shelves and distally steepened ramps, in contrast, may develop lowstand talus or turbiditic wedges. Distally steepened ramps may behave more like homoclinal ramps during minor base-level falls and like rimmed shelves during major base-level falls. Many ramps consist of layered successions of several ramp sequences stacked one upon the other. Ramp "stacks" of this sort may show gross vertical accretion, but individual ramp sequences seldom appear to develop in a "keep-up" style, apart from minor organic buildups, as with many rimmed shelves. Steepening of the outer-ramp margin due to tectonism, slope inheritance, or differential sedimentation may promote the development of a distally steepened ramp or rimmed shelf. A wide variety of organisms have constructed buildups in mid- and outer-ramp environments. Isolated buildups may seed early in ramp development, accrete to wave base or sea level, and continue growth by stacking through successive ramp sequences so that depositional and diagenetic features within them are in concert with those of the shallow ramp. The location of isolated buildups on ramps is governed by tectonism, halokinesis, antecedent topography, or by the subtle slope geometry of the previous ramp sequence. Diagenesis on ramps shows some major variations compared with diagenesis on steep-sloped, flat-topped carbonate platforms. Ramp-bounded basins may form prolific petroleum sourcing and reservoiring systems and offer a range of subtle stratigraphic play types and lateral facies variations which determine reservoir quality and distribution. Isolated buildups in the mid- and outer-ramp environments represent one of the commonest petroleum reservoirs in ramp systems and tend to have their foundations in transgressive systems tracts. Grainstone and packstone res

Burchette, T. P.; Wright, V. P.

1992-08-01

326

Development of carbon/carbon composites with carbon nanotubes as reinforcement and chemical vapor infiltration carbon as matrix.  

PubMed

Carbon nanotubes based carbon/carbon composites were prepared by infiltration of purified ACNTs film with pyrolytic carbon. Densification was performed by filling the space between the CNTs through by deposition of the pyrocarbon on the nanotubes surface. It comprised of (i) Synthesis and purification of aligned carbon nanotubes films by CCVD process and (ii) Infiltration of CNTs film by pyrocarbon using CVI method at 950 degrees C. SEM studies showed that the film was well infiltrated using methane. The density of film increased to 1.4 gm/cm3 from 0.4 gm/cm3 of as purified ACNTs film. The I(D)/I(G) ratio for CNTs film is 0.67 and 0.80 for the CVI deposited pyrocarbon. The lower I(D)/I(G) ratio from Raman microscopy shows fine graphitic nature of carbon nanotubes and nanocomposites films. PMID:19452978

Manocha, L M; Patel, Harshad; Manocha, S; Roy, Ajit K; Singh, J P

2009-05-01

327

Differential Scanning Calorimetry (DSC) for the Analysis of Activated Carbon.  

National Technical Information Service (NTIS)

The technique of Differential Scanning Calorimetry (DSC) has been applied to the characterization and the analysis of several activated carbons. These activated carbons included BPL carbon (a base carbon), ASC carbon (a BPL carbon impregnated with copper,...

L. E. Cameron S. H. Liang

1991-01-01

328

Carbon Nanotube Interconnect  

NASA Technical Reports Server (NTRS)

Method and system for fabricating an electrical interconnect capable of supporting very high current densities ( 10(exp 6)-10(exp 10) Amps/sq cm), using an array of one or more carbon nanotubes (CNTs). The CNT array is grown in a selected spaced apart pattern, preferably with multi-wall CNTs, and a selected insulating material, such as SiOw, or SiuNv is deposited using CVD to encapsulate each CNT in the array. An exposed surface of the insulating material is planarized to provide one or more exposed electrical contacts for one or more CNTs.

Li, Jun (Inventor); Meyyappan, Meyya (Inventor)

2006-01-01

329

Silicon Encapsulated Carbon Nanotubes  

PubMed Central

A dual stage process of depositing bamboo-like carbon nanotubes (BCNTs) by hot filament chemical vapor deposition (HFCVD) and coating Si using Radio frequency sputtering (RFS) technique. The films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron field emission studies (EFE). SEM results suggest a dense network of homogeneous silicon-coated BCNTs. From the comprehensive analysis of the results provided by these techniques emerges the picture of Si encapsulated BCNTs.

2010-01-01

330

Carbon-Nanotube Optoelectronics  

Microsoft Academic Search

\\u000a Semiconducting single-walled carbon nanotubes are direct-gap materials that\\u000a provide ideal systems for the study of photophysics in one-dimension. While\\u000a their excited states involve strongly bound 1D excitons, their single atomic\\u000a layer structure makes their optical properties especially sensitive to their\\u000a environment and external fields, thus allowing for their controlled modification. In\\u000a this chapter we review the properties of the excited

Phaedon Avouris; Marcus Freitag; Vasili Perebeinos

331

Ultrahigh Carbon Steels  

NASA Astrophysics Data System (ADS)

Recent studies and results on ultrahigh carbon (UHC) steels suggest that major development efforts on these steels are timely and that programs to evaluate prototype structural components should be initiated. These recent results include: the development of economical processing techniques incorporating a divorced eutectoid transformation, the improvement of room temperature strength and ductility by heat treatment, the enhancement of superplastic properties through dilute alloying with silicon, and the attainment of exceptional notch impact strength in laminated UHC steel composites manufactured through solid state bonding. The unique mechanical properties achieved in UHC steels are due to the presence of micron-size fer-rite grains and ultrafine spheroidized carbides.

Sherby, O. D.; Oyama, T.; Kum, D. W.; Walser, B.; Wadsworth, J.

1985-06-01

332

Radiation stability of carbon nanostructures  

Microsoft Academic Search

A theoretical study of the radiation stability of carbon nanostructures irradiated by an electron beam has been made. Calculations\\u000a have been performed with the use of an analytical expression for the cross-section for scattering of relativistic electrons\\u000a by carbon atoms, as well as of the data on the threshold energy of atomic displacement from the carbon lattice obtained by\\u000a the

G. Ya. Gerasimov

2010-01-01

333

Adsorption on the carbon nanotubes  

Microsoft Academic Search

Adsorption on single walled carbon nanotubes (SWCNTs) is a subject of growing experimental and theoretical interest. The possible\\u000a adsorbed patterns of atoms and molecules on the single-walled carbon nanotubes vary with the diameters and chirality of the\\u000a tubes due to the confinement. The curvature of the carbon nanotube surface enlarges the distance of the adsorbate atoms and\\u000a thus enhances the

Yi Ding; Xiao-Bao Yang; Jun Ni

2006-01-01

334

Conservation tillage for carbon sequestration  

Microsoft Academic Search

World soils represent the largest terrestrial pool of organic carbon (C), about 1550 Pg compared with about 700 Pg in the\\u000a atmosphere and 600 Pg in land biota. Agricultural activities (e.g., deforestation, burning, plowing, intensive grazing) contribute\\u000a considerably to the atmospheric pool. Expansion of agriculture may have contributed substantially to the atmospheric carbon\\u000a pool. However, the exact magnitude of carbon

R. Lal; J. M. Kimble

1997-01-01

335

Carbon nanotube applications in microelectronics  

Microsoft Academic Search

The extraordinary characteristics of carbon nanotubes make them a promising candidate for applications in microelectronics. Catalyst-mediated chemical vapor deposition growth is very well suited for selective in-situ growth of nanotubes compatible with the requirements of microelectronics technology. This deposition method can be exploited for carbon nanotube vias. Semiconducting single-walled tubes can be successfully operated as carbon nanotube field effect transistors

Wolfgang Hoenlein; Franz Kreupl; Georg Stefan Duesberg; Andrew Peter Graham; Maik Liebau; Robert Viktor Seidel; Eugen Unger

2004-01-01

336

Ocean uptake of carbon dioxide  

Microsoft Academic Search

Factors controlling the capacity of the ocean for taking up anthropogenic C0[sup 2] include carbon chemistry, distribution of alkalinity, pCO[sup 2] and total concentration of dissolved C0[sup 2], sea-air pCO[sup 2] difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these

Tsung-Hung Peng; Taro Takahashi

1993-01-01

337

Ocean uptake of carbon dioxide  

Microsoft Academic Search

Factors controlling the capacity of the ocean for taking up anthropogenic C0² include carbon chemistry, distribution of alkalinity, pCO² and total concentration of dissolved C0², sea-air pCO² difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and

Tsung-Hung Peng; Taro Takahashi

1993-01-01

338

What is the Carbon Cycle?  

NSDL National Science Digital Library

This activity has students explore the carbon cycle and learn to identify carbon sources, sinks, and release agents. They will come to understand that carbon is critical to the biosphere and must continue cycling to support life on earth. The instructor guide contains detailed background material, learning goals, alignment to national standards, grade level/time, details on materials and preparation, procedure, assessment ideas, and modifications for alternative learners.

2007-12-12

339

Carbon-assisted flyer plates  

DOEpatents

A laser driven flyer plate utilizing an optical fiber connected to a laser. The end of the optical fiber has a layer of carbon and a metal layer deposited onto it. The carbon layer provides the laser induced plasma which is superior to the plasma produced from most metals. The carbon layer plasma is capable of providing a flatter flyer plate, converting more of the laser energy to driving plasma, promoting a higher flyer plate acceleration, and providing a more uniform pulse behind the plate. In another embodiment, the laser is in optical communication with a substrate onto which a layer of carbon and a layer of metal have been deposited.

Stahl, David B. (Los Alamos, NM); Paisley, Dennis L. (Santa Fe, NM)

1994-01-01

340

Exploring Marine Carbon Isotope Excursions  

NSDL National Science Digital Library

David Jones, Geology Department, Amherst College Topic: stable isotopes, geochemistry, oceanography, carbon cycle Course type: Upper level undergraduate course Description The exercise is designed to introduce ...

341

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.

2012-03-01

342

The Carbon Cycle Science Program  

NSDL National Science Digital Library

The US Global Change Research Program (USGCRP) provides this site with the purpose of supplying "critical unbiased scientific information on the fate of carbon dioxide in the environment to contribute to the ongoing public dialogue." The USGCRP's focus for the fiscal year 2000 is on determining the location, magnitude, and use of carbon sinks in North America. Sections of the site include Current Research Activities, Contacts, Program and Science Planning, and Meetings and Workshops. Users can download The Carbon Cycle Science Plan in .pdf format and also obtain specific, current information on the background and goals of the Carbon Cycle Science Program initiative.

343

Refractory Oxidative-Resistant Ceramic Carbon Insulation  

NASA Technical Reports Server (NTRS)

High-temperature, lightweight, ceramic carbon insulation is prepared by coating or impregnating a porous carbon substrate with a siloxane gel derived from the reaction of an organodialkoxy silane and an organotrialkoxy silane in an acid or base medium in the presence of the carbon substrate. The siloxane gel is subsequently dried on the carbon substrate to form a ceramic carbon precursor. The carbon precursor is pyrolyzed, in an inert atmosphere, to form the ceramic insulation containing carbon, silicon, and oxygen. The carbon insulation is characterized as a porous, fibrous, carbon ceramic tile which is particularly useful as lightweight tiles for spacecraft.

Leiser, Daniel B. (Inventor); Hsu, Ming-Ta S. (Inventor); Chen, Timothy S. (Inventor)

2001-01-01

344

Carbon Nanotube Purification  

NASA Technical Reports Server (NTRS)

A method for cleaning or otherwise removing amorphous carbon and other residues that arise in growth of a carbon nanotube (CNT) array. The CNT array is exposed to a plurality of hydroxyls or hydrogen, produced from a selected vapor or liquid source such as H2O or H2O2. and the hydroxyls or hydrogen (neutral or electrically charged) react with the residues to produce partly or fully dissolved or hydrogenated or hydroxylizated products that can be removed or separated from the CNT array. The hydroxyls or hydrogen can be produced by heating the CNT array, residue and selected vapor or liquid source or by application of an electromagnetic excitation signal with a selected frequency or range of frequencies to dissociate the selected vapor or liquid. The excitation frequency can be chirped to cover a selected range of frequencies corresponding to dissociation of the selected vapor or liquid. Sonication may be uscd to supplement dissociation of the H2O and/or H2O2.

Delzeit, Lance D. (Inventor); Delzeit, Clement J. (Inventor)

2005-01-01

345

Carbon dioxide and climate  

SciTech Connect

Scientific and public interest in greenhouse gases, climate warming, and global change virtually exploded in 1988. The Department's focused research on atmospheric CO{sub 2} contributed sound and timely scientific information to the many questions produced by the groundswell of interest and concern. Research projects summarized in this document provided the data base that made timely responses possible, and the contributions from participating scientists are genuinely appreciated. In the past year, the core CO{sub 2} research has continued to improve the scientific knowledge needed to project future atmospheric CO{sub 2} concentrations, to estimate climate sensitivity, and to assess the responses of vegetation to rising concentrations of CO{sub 2} and to climate change. The Carbon Dioxide Research Program's goal is to develop sound scientific information for policy formulation and governmental action in response to changes of atmospheric CO{sub 2}. The Program Summary describes projects funded by the Carbon Dioxide Research Program during FY 1990 and gives a brief overview of objectives, organization, and accomplishments.

Not Available

1990-10-01

346

Carbon fiber modification  

NASA Technical Reports Server (NTRS)

The effect of several chemical treatments on the electrical and mechanical properties of carbon fibers was investigated with an optimum goal of increasing the electrical resistivity by a factor of 1000 without appreciably changing the mechanical properties. It was possible to effect resistivity increases from 10 to 50 percent without adversely affecting the tensile strength or Young's modulus for T-300 and C-6000 PAN fibers by treatments with either AlCl3 or nitric acid mixtures. Larger increases in the resistivity were produced with pitch fibers treated with nitric acid mixtures. This treatment also produced a partial decomposition of the pitch fiber and deterioration of the mechanical properties. The rationale behind the approch was to immobilize the conductivity producing pi electrons in the microscopic aromatic structure of the carbon fibers without destroying the strength producing sigma bonds. The investigations indicate that certain chemical treatments can produce such results, but the total reduction in the electrical conductivity which was achieved was not large enough to impact on problems which might arise from the high conductivities of the fibers.

Thompson, T. E.

1979-01-01

347

Carbon nanotube array actuators  

NASA Astrophysics Data System (ADS)

Experimental investigations of highly vertically aligned carbon nanotubes (CNTs), also known as CNT-arrays, are the main focus of this paper. The free strain as result of an active material behavior is analyzed via a novel experimental setup. Previous test experiences of papers made of randomly oriented CNTs, also called Bucky-papers, reveal comparably low free strain. The anisotropy of aligned CNTs promises better performance. Via synthesis techniques like chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD), highly aligned arrays of multi-walled carbon nanotubes (MWCNTs) are synthesized. Two different types of CNT-arrays are analyzed, morphologically first, and optically tested for their active characteristics afterwards. One type of the analyzed arrays features tube lengths of 750-2000 ?m with a large variety of diameters between 20 and 50 nm and a wave-like CNT-shape. The second type features a maximum, almost uniform, length of 12 ?m and a constant diameter of 50 nm. Different CNT-lengths and array types are tested due to their active behavior. As result of the presented tests, it is reported that the quality of orientation is the most decisive property for excellent active behavior. Due to their alignment, CNT-arrays feature the opportunity to clarify the actuation mechanism of architectures made of CNTs.

Geier, S.; Mahrholz, T.; Wierach, P.; Sinapius, M.

2013-09-01

348

Mass Spectrometric Study of the Yttrium-Carbon System.  

National Technical Information Service (NTIS)

A high temperature investigation of the vapor in thermodynamic equilibrium with the Y-C condensed system was carried out in the temperature range 2075-2340 K. Y and YC2 are shown to be important species in the vapor phase. Utilizing the pressure independe...

G. De Maria M. Guido L. Malaspina B. Pesce

1965-01-01

349

Oxygen reduction activity of carbon nitride supported on carbon nanotubes.  

PubMed

Fuel cells offer an alternative to burning fossil fuels, but use platinum as a catalyst which is expensive and scarce. Cheap, alternative catalysts could enable fuel cells to become serious contenders in the green energy sector. One promising class of catalyst for electrochemical oxygen reduction is iron-containing, nanostructured, nitrogen-doped carbon. The catalytic activity of such N-doped carbons has improved vastly over the years bringing industrial applications ever closer. Stoichiometric carbon nitride powder has only been observed in recent years. It has nitrogen content up to 57% and as such is an extremely interesting material to work with. The electrochemical activity of carbon nitride has already been explored, confirming that iron is not a necessary ingredient for 4-electron oxygen reduction. Here, we synthesize carbon nitride on a carbon nanotube support and subject it to high temperature treatment in an effort to increase the surface area and conductivity. The results lend insight into the mechanism of oxygen reduction and show the potential for carbon nanotube-supported carbon nitride to be used as a catalyst to replace platinum in fuel cells. PMID:22905547

Lyth, S M; Nabae, Y; Islam, N M; Kuroki, S; Kakimoto, M; Miyata, S

2012-06-01

350

Role of activated carbon pellets in carbon dioxide removal  

Microsoft Academic Search

The removal of carbon dioxide from gas\\/air streams is more often becoming necessary in many industries for different purposes. In cryogenic air separation plant, air has to be free from carbon dioxide before its liquefaction otherwise blockage due to freezing of heat exchange equipment would result. Enrichment of methane in biogas to have fuel of higher calorific value can be

S. C Sarkar; A Bose

1997-01-01

351

Helicity of Carbon Nanotubes and Helix-shaped Carbon Nanotubes  

Microsoft Academic Search

Determination of the helicity of carbon nanotubes (CNTs) is useful for CNTs in nanoelectronic device applications. Using electron diffraction to measure chiral angle with a high precision is reviewed, and helix-shaped carbon nanostructures are introduced and characterized by transmission electron microscopy. The possible formation mechanism of helix-shaped CNTs is also referred in the paper

Ji-Peng Cheng; Xiao-Bin Zhang

2006-01-01

352

Carbon Management Response curves: estimates of temporal soil carbon dynamics.  

PubMed

Measurement of the change in soil carbon that accompanies a change in land use (e.g., forest to agriculture) or management (e.g., conventional tillage to no-till) can be complex and expensive, may require reference plots, and is subject to the variability of statistical sampling and short-term variability in weather. In this paper, we develop Carbon Management Response (CMR) curves that could be used as an alternative to in situ measurements. The CMR curves developed here are based on quantitative reviews of existing global analyses and field observations of changes in soil carbon. The curves show mean annual rates of soil carbon change, estimated time to maximum rates of change, and estimated time to a new soil carbon steady state following the initial change in management. We illustrate how CMR curves could be used in a carbon accounting framework while effectively addressing a number of potential policy issues commonly associated with carbon accounting. We find that CMR curves provide a transparent means to account for changes in soil carbon accumulation and loss rates over time, and also provide empirical relationships that might be used in the development or validation of ecological or Earth systems models. PMID:15453404

West, Tristram O; Marland, Gregg; King, Anthony W; Post, Wilfred M; Jain, Atul K; Andrasko, Kenneth

2004-04-01

353

Ultrathin diamondlike carbon films deposited by filtered carbon vacuum arcs  

Microsoft Academic Search

Ultrathin (<5 nm) hard carbon films are of great interest to the magnetic storage industry as the areal density approaches 100 Gb\\/in 2. These films can be used as overcoats to protect the magnetic layer. Tetrahedrally bonded amorphous carbon (ta-C) films can be produced by filtered cathodic arc deposition, however, these films will be accepted by the storage industry only

A. Anders; F. W. Ryan; W. Fong; C. S. Bhatia

2000-01-01

354

Oxidation Microstructure Studies of Reinforced Carbon/Carbon.  

National Technical Information Service (NTIS)

Laboratory oxidation studies of reinforced carbon/carbon (RCC) are discussed with particular emphasis on the resulting microstructures. This study involves laboratory furnace (500-1500 C deg) and arc-jet exposures (1538 C deg) on various forms of RCC. RCC...

N. S. Jacobson D. M. Curry

2006-01-01

355

Stuffing Carbon Away: Mechanisms of Carbon Sequestration in Soils  

Microsoft Academic Search

Soils offer the potential to sequester large quantities of carbon from the atmosphere for decades to millennia and so may ameliorate the anthropogenic influence of fossil fuel release. However changes in climate can drastically affect the soil's ability to store carbon through changes mineralogy on time scales of human interest. It is essential to understand the major controls on soil

P J Reimer; C A Masiello; J R Southon; S E Trumbore; J W Harden; A F White; O A Chadwick; M S Torn

2003-01-01

356

Friction stir welding of carbon steels  

Microsoft Academic Search

In order to determine the effect of the carbon content and the transformation on the mechanical properties and microstructures of the FSW carbon steel joints, three types of carbon steels with different carbon contents (IF steel, S12C, S35C) were friction stir welded under various welding conditions. Compared with IF steel, the microstructures and mechanical properties of the carbon steel joints

Hidetoshi Fujii; Ling Cui; Nobuhiro Tsuji; Masakatsu Maeda; Kazuhiro Nakata; Kiyoshi Nogi

2006-01-01

357

Advanced solar collector concepts using carbon  

Microsoft Academic Search

The chemical inertness of carbon, its black color, good thermal conductivity, and fabricability into a variety of physical forms makes it attractive as a material of construction for a family of unique and advanced second-generation solar collectors. Several carbon-based solar collector heat transport conceptual systems are described using carbon microspheroids, carbon pile fibers and whiskers, and reticulated (open pore) carbon

O. C. Baldonado; C. R. Schmitt

1981-01-01

358

Carbon nanotubes analysis, classification and characterization  

Microsoft Academic Search

Different nanostructures, electronic nanodevices, nanoresonators, nanoswitches and other devices have been devised, designed and fabricated using carbon nanotubes. Carbon nanotubes are among the promising carbon-based solutions that have been attracted a significant attention in last years. This paper examines important problems in carbon nanotubes analysis, classification and characterization using experimental data. In particular, we classify carbon nanotubes as metallic, semimetallic

M. A. Lyshevski

2004-01-01

359

The Carbon Cycle: How It Works  

NSDL National Science Digital Library

In this game, learners walk through an imaginary Carbon Cycle and explore the ways in which carbon is stored in reservoirs and the processes that transport the carbon atom from one location to another. This resource includes background information about carbon, the carbon cycle, and climate change.

Meier, Beverly L.

2012-07-20

360

Comparison of the electrochemical behavior of carbon aerogels and activated carbon fiber cloths.  

National Technical Information Service (NTIS)

Electrochemical capacitative behavior of carbon aerogels and commercial carbon fiber cloths was studied in 5M KOH, 3M sulfuric acid, and 0.5M tetrethylammonium tetrafluoroborate/propylene carbonate electrolytes. The resorcinol-formaldehyde based carbon ae...

T. D. Tran C. T. Alviso S. S. Hulsey J. K. Nielsen R. W. Pekala

1996-01-01

361

46 CFR 151.50-40 - Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether.  

Code of Federal Regulations, 2010 CFR

... Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether...the cargo hose. This electrical bonding shall be maintained until after...requirements of § 151.50-41 for carbon disulfide (carbon bisulfide...

2009-10-01

362

46 CFR 151.50-40 - Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether.  

Code of Federal Regulations, 2010 CFR

... Additional requirements for carbon disulfide (carbon bisulfide) and ethyl ether...the cargo hose. This electrical bonding shall be maintained until after...requirements of § 151.50-41 for carbon disulfide (carbon bisulfide...

2010-10-01

363

Compressed carbon nanotubes: A family of new multifunctional carbon allotropes  

PubMed Central

The exploration of novel functional carbon polymorphs is an enduring topic of scientific investigations. In this paper, we present simulations demonstrating metastable carbon phases as the result of pressure induced carbon nanotube polymerization. The configuration, bonding, electronic, and mechanical characteristics of carbon polymers strongly depend on the imposed hydrostatic/non-hydrostatic pressure, as well as on the geometry of the raw carbon nanotubes including diameter, chirality, stacking manner, and wall number. Especially, transition processes under hydrostatic/non-hydrostatic pressure are investigated, revealing unexpectedly low transition barriers and demonstrating sp2?sp3 bonding changes as well as peculiar oscillations of electronic property (e.g., semiconducting?metallic?semiconducting transitions). These polymerized nanotubes show versatile and superior physical properties, such as superhardness, high tensile strength and ductility, and tunable electronic properties (semiconducting or metallic).

Hu, Meng; Zhao, Zhisheng; Tian, Fei; Oganov, Artem R.; Wang, Qianqian; Xiong, Mei; Fan, Changzeng; Wen, Bin; He, Julong; Yu, Dongli; Wang, Hui-Tian; Xu, Bo; Tian, Yongjun

2013-01-01

364

Intermediate Temperature Carbon - Carbon Composite Structures. CRADA Final Report  

SciTech Connect

The objective of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC (the "Contractor") and Synterials, Inc. (the "Participant") was to demonstrate promising processing methods, which can lead to producing Carbon-Carbon Composites (CCC), with tensile and interlaminar properties comparable to those of organic matrix composites and environmental stability at 1200 F for long periods of time. The participant synthesized carbon-carbon composites with two different fiber coatings and three different matrices. Both parties evaluated the tensile and interlaminar properties of these materials and characterized the microstructure of the matrices and interfaces. It was found that fiber coatings of carbon and boron carbide provided the best environmental protection and resulted in composites with high tensile strength.

Lara-Curzio, Edgar [ORNL

2007-06-01

365

Electron Beam Exposure of Thermal Control Paints on Carbon-Carbon and Carbon-Polyimide Composites  

NASA Technical Reports Server (NTRS)

Carbon-carbon and carbon-polyimide composites are being considered for use as radiator face sheets or fins for space radiator applications. Several traditional white thermal control paints are being considered for the surface of the composite face sheets or fins. One threat to radiator performance is high energy electrons. The durability of the thermal control paints applied to the carbon-carbon and carbon-polyimide composites was evaluated after extended exposure to 4.5 MeV electrons. Electron exposure was conducted under argon utilizing a Mylar(TradeMark) bag enclosure. Solar absorptance and infrared emittance was evaluated before and after exposure to identify optical properties degradation. Adhesion of the paints to the carbon-carbon and carbon-polyimide composite substrates was also of interest. Adhesion was evaluated on pristine and electron beam exposed coupons using a variation of the ASTM D-3359 tape test. Results of the optical properties evaluation and the adhesion tape tests are summarized.

Jaworske, Donald A.

2006-01-01

366

The carbon brace  

PubMed Central

Background The CMCR brace (Corset MonocoqueCarbone respectant la Respiration –which means Monoshell Carbon Brace respecting Breathing) is an innovative brace, used in orthopaedic treatment for progressive thoracic, thoraco-lumbar or combined scoliosis, whatever their etiology. It can be used at the very young age without disrupting the chest growth, but should be kept for reducible scoliosis in older teenagers. Brace description and principles The CMCR brace is monoshell while retaining the corrective principle of the polyvalve Lyon brace with one or two supports (brace “pads”) located on hump(s).In contrast to Lyon brace made of plexidur and structured by metal reinforcement with adjustable but fixed localized supports, the CMCR brace is made of polyethylene and carbon with adjustable and mobile supports. This mobility provides a permanent pressure, which varies depending on ribs and spine movements. The correction is obtained without spinal extension so that each respiratory movement takes part in a gradual return to dorsal kyphosis. Results Results were presented in two published analysis: •?In the first retrospective study about 115 patients, French-published in the Annals of Physical Medicine and Rehabilitation (2005), the CMCR brace stabilized moderate scoliosis, decreased the vital capacity (VC) of 13% compared to the VC without brace, and did not have sufficient impact on the hump reduction. Treatment had better results when started at Risser 3 or 4 than Risser 0, 1, 2. The brace was then modified to increase the dorsal pad pressure and the location of correction forces was defined more precisely through the use of 3D analysis. •?The second study published in Scoliosis (2011) mainly focused on the impact on VC at brace setting up and followed a cohort of 90 patients treated with CMCR. Girls as well as boys increased VC during treatment, and at brace definitive removal, VC had increased of 21% from the initial value, whereas the theoretical VC at the same time rose by 18%. The difference between the time where the child actually wears its brace and the time asked by the clinician for the brace to be worn is only 1 hour, which means that this brace is accepted by teenagers. Conclusions Orthopaedic treatment is still a heavy treatment for teenagers in growth period. This orthosis is designed to partly maintain spine and chest mobility. We hope so to have part in improving life conditions of these teenagers, compared to those treated with rigid braces.

2013-01-01

367

Method of Making Carbon Fiber-carbon Matrix Reinforced Ceramic Composites.  

National Technical Information Service (NTIS)

A method of making a carbon fiber-carbon matrix reinforced ceramic composite wherein the result is a carbon fiber-carbon matrix reinforcement is embedded within a ceramic matrix. The ceramic matrix does not penetrate into the carbon fiber-carbon matrix re...

B. Williams R. Benander

2007-01-01

368

Australian climate-carbon cycle feedback reduced by soil black carbon  

Microsoft Academic Search

Annual emissions of carbon dioxide from soil organic carbon are an order of magnitude greater than all anthropogenic carbon dioxide emissions taken together. Global warming is likely to increase the decomposition of soil organic carbon, and thus the release of carbon dioxide from soils, creating a positive feedback. Current models of global climate change that recognize this soil carbon feedback

Johannes Lehmann; Jan Skjemstad; Saran Sohi; John Carter; Michele Barson; Pete Falloon; Kevin Coleman; Peter Woodbury; Evelyn Krull

2008-01-01

369

SOURCE ASSESSMENT: CARBON BLACK MANUFACTURE  

EPA Science Inventory

The report summarizes the assessment of air emissions from the manufacture of carbon black, currently manufactured in the U.S. by two major processes: thermal and oil furnace. Sources of atmospheric emissions within oil furnace plants (about 90% of the 30 U.S. carbon black plants...

370

Carbon nanotubes: opportunities and challenges  

Microsoft Academic Search

Carbon nanotubes are graphene sheets rolled-up into cylinders with diameters as small as one nanometer. Extensive work carried out worldwide in recent years has revealed the intriguing electrical and mechanical properties of these novel molecular scale wires. It is now well established that carbon nanotubes are ideal model systems for studying the physics in one-dimensional solids and have significant potential

Hongjie Dai

2002-01-01

371

Half-metallic carbon nanotubes.  

PubMed

Half-metallicity in carbon nanotubes is achieved and controlled by hydrogen adsorption patterns. The edge states in carbon nanotubes are unstable under an electric field due to the spin-conserving electron transfer between the edges, but a large enough transfer barrier between the edge states, obtained by controlling the adsorption patterns, renders the CNTs half-metallic. PMID:22419361

Lee, Kyu Won; Lee, Cheol Eui

2012-04-17

372

Carbon Sequestration in Campus Trees  

NSDL National Science Digital Library

In this activity, students use a spreadsheet to calculate the net carbon sequestration in a set of trees; they will utilize an allometric approach based upon parameters measured on the individual trees. They determine the species of trees in the set, measure trunk diameter at a particular height, and use the spreadsheet to calculate carbon content of the tree using forestry research data.

Cole, Robert S.; Spreadsheets Across the Curruculum; Washington Center; Science Education Resource Center (SERC)

373

Is Carbon Hard or Soft?  

NSDL National Science Digital Library

The representation shows differences in the arrangement of carbon atoms that make up diamonds and graphite. Through text and pictures, the resource describes the difference in arrangement of two different carbon allotropes. The text relates the differences in arrangements to differences in the hardness (properties) of the materials.

374

Microbial growth on carbon monoxide  

Microsoft Academic Search

The utilization of carbon monoxide as energy and\\/or carbon source by different physiological groups of bacteria is described and compared. Utilitarian CO oxidation which is coupled to the generation of energy for growth is achieved by aerobic and anaerobic eu- and archaebacteria. They belong to the physiological groups of aerobic carboxidotrophic, facultatively anaerobic phototrophic, and anaerobic acetogenic, methanogenic or sulfate-reducing

Gerhard Mörsdorf; Kurt Frunzke; Dilip Gadkari; Ortwin Meyer

1992-01-01

375

Carbon Nanotube Nucleated Polymer Crystallization  

Microsoft Academic Search

Crystallinity studies were performed on carbon nanotube?doped Poly(m?phenylenevinylene?co?2,5?dioctyloxy?p?phenylenevinylene) (PmPV) and Poly (vinyl alcohol) (PVOH). Differential Scanning Calorimetry (DSC) of the composites verified that carbon nanotubes nucleate polymer crystallization.

K. P. Ryan; M. Cadek; A. Drury; M. Ruether; W. J. Blau; J. N. Coleman

2005-01-01

376

CARBON NANOTUBES AS MULTIPOLLUTANT SORBENTS  

EPA Science Inventory

Exploratory Research Program Project - Carbon nanotubes (CNTs) are formed from graphite (or graphene) sheets rolled into tubes, typically with diameters of 1 - 10 nm and lengths of 200 - 500 nm. Carbon nanotubes have unique electrical properties that have led to interest in thei...

377

Quantum Transport in Carbon Nanotubes  

Microsoft Academic Search

We present a tutorial introduction into the structure and electronic properties of carbon nanotubes which may serve as an\\u000a entry point into the literature on the field. Some of the original experiments in the field are selected to illustrate the\\u000a richness of quantum transport in single-and multi-wall carbon nanotubes.

Elsa Thune; Christoph Strunk

2005-01-01

378

LAKE SUPERIOR ORGANIC CARBON BUDGET  

EPA Science Inventory

The organic carbon concentration of Lake Superior is discussed in terms of a simple mathematical model that treats the lake as a well mixed basin. Major sources, outflows, and biochemically mediated removal of organic carbon are analyzed in the time frame of yearly average values...

379

Carbon Sequestration Research and Development.  

National Technical Information Service (NTIS)

The goal of this report is to identify key areas for research and development (R&D) that could lead to an understanding of the potential for future use of carbon sequestration as a major tool for managing carbon emissions. Under the leadership of DOE, res...

A. Palmisano A. Wolsky B. Kane D. Reichle G. Hendrey G. Jacobs H. Herzog J. Clarke J. Ekmann J. Houghton J. Hunter-Cevera J. Ogden J. Stringer M. York N. Woodward R. Dahlman R. Judkins R. Socolow S. Benson T. Surles

1999-01-01

380

Forest soils and carbon sequestration  

Microsoft Academic Search

Soils in equilibrium with a natural forest ecosystem have high carbon (C) density. The ratio of soil:vegetation C density increases with latitude. Land use change, particularly conversion to agricultural ecosystems, depletes the soil C stock. Thus, degraded agricultural soils have lower soil organic carbon (SOC) stock than their potential capacity. Consequently, afforestation of agricultural soils and management of forest plantations

R. Lal

2005-01-01

381

History of ultrahigh carbon steels  

Microsoft Academic Search

The history and development of ultrahigh carbon steels (i.e., steels containing between 1 and 2.l percent C and now known as UHCS) are described. The early use of steel compositions containing carbon contents above the eutectoid level is found in ancient weapons from around the world. For example, both Damascus and Japanese sword steels are hypereutectoid steels. Their manufacture and

J. Wadsworth; O. D. Sherby

1997-01-01

382

Psychological effectiveness of carbon labelling  

NASA Astrophysics Data System (ADS)

Despite the decision by supermarket-giant Tesco to delay its plan to add carbon-footprint information onto all of its 70,000 products, carbon labelling, if carefully designed, could yet change consumer behaviour. However, it requires a new type of thinking about consumers and much additional work.

Beattie, Geoffrey

2012-04-01

383

Closing the fuel carbon cycle  

SciTech Connect

The global carbon cycle involves constant exchange of carbon atoms between the atmosphere, land, and ocean through biological, chemical and geological processes. This natural cycle of uptake and release of carbon is roughly in balance. However, the global industrialization of the past two centuries has released carbon to the atmosphere, mostly in the form of CO{sub 2} that had been locked up in underground coal, oil, and natural gas deposits for millions of years. It is primarily combustion of these long-stored fossil fuels that threatens to tip the balance of the carbon cycle, leading to a substantial buildup of CO{sub 2} in the upper atmosphere. Scientists believe that one key to stabilizing future atmospheric CO{sub 2} concentrations will be essentially to close the fuel carbon cycle, to capture the carbon from fossil fuels before it is released to the atmosphere and return it to permanent reservoirs in the earth or oceans. The article summarises the various options for carbon capture and storage (CCS) and looks at the state of development of technologies. It also addresses regulatory uncertainties, legal issues risks and perceptions of CCS. 3 figs., 1 tab.

Powicki, C.R.

2007-04-01

384

Tungsten disulphide sheathed carbon nanotubes.  

PubMed

An insulated nanotube wire is formed by the binary phase of layered tungsten disulphide and carbon nanotubes (shown in the HRTEM image) generated by the sulphidization of tungsten oxide coated multiwalled carbon nanotubes at 900 °C. Thermogravimetric analysis shows that the tungsten disulphide coat acts as an antioxidant. PMID:23686882

Whitby, R L; Hsu, W K; Boothroyd, C B; Fearon, P K; Kroto, H W; Walton, D R

2001-10-15

385

Carbon nanofibers for composite applications  

Microsoft Academic Search

Carbon nanofibers and nanotubes are promising to revolutionise several fields in material science and are suggested to open the way into nanotechnology. Further market development will depend on material availability at reasonable prices. We have achieved bulk production capacities of high purity carbon nanofibers (CNFs) at low cost by a catalytic chemical vapour deposition (CCVD) process. Reasonably low temperatures and

E. Hammel; X. Tang; M. Trampert; T. Schmitt; K. Mauthner; A. Eder; P. Pötschke

2004-01-01

386

Carbon fiber counting. [aircraft structures  

NASA Technical Reports Server (NTRS)

A method was developed for characterizing the number and lengths of carbon fibers accidentally released by the burning of composite portions of civil aircraft structure in a jet fuel fire after an accident. Representative samplings of carbon fibers collected on transparent sticky film were counted from photographic enlargements with a computer aided technique which also provided fiber lengths.

Pride, R. A.

1980-01-01

387

Carbon nanotube yarn strain sensors  

Microsoft Academic Search

Carbon nanotube (CNT) based sensors are often fabricated by dispersing CNTs into different types of polymer. In this paper, a prototype carbon nanotube (CNT) yarn strain sensor with excellent repeatability and stability for in situ structural health monitoring was developed. The CNT yarn was spun directly from CNT arrays, and its electrical resistance increased linearly with tensile strain, making it

Haibo Zhao; Yingying Zhang; Philip D. Bradford; Qian Zhou; Quanxi Jia; Fuh-Gwo Yuan; Yuntian Zhu

2010-01-01

388

BIG SKY CARBON SEQUESTRATION PARTNERSHIP  

Microsoft Academic Search

The Big Sky Carbon Sequestration Partnership, led by Montana State University, is comprised of research institutions, public entities and private sectors organizations, and the Confederated Salish and Kootenai Tribes and the Nez Perce Tribe. Efforts under this Partnership fall into four areas: evaluation of sources and carbon sequestration sinks; development of GIS-based reporting framework; designing an integrated suite of monitoring,

Susan M. Capalbo

2004-01-01

389

Advancing Climate and Carbon Simulation.  

National Technical Information Service (NTIS)

We use a recently developed integrated climate/carbon model to perform breakthrough studies of the climate. Two major studies are carried out--namely the effects of CO(sub 2)-fertilized vegetation on global climate and carbon dynamics, and the effect of c...

S. Thompson

2004-01-01

390

Earth's Carbon Metabolism-Revealed  

NSDL National Science Digital Library

In this problem set, learners will use a map of satellite data of Earth's carbon "metabolism" or Net Primary Production to answer a series of questions about carbon removal. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

391

Superconducting properties of carbon nanotubes  

NASA Astrophysics Data System (ADS)

Metallic single wall carbon nanotubes have attracted much interest as 1D quantum wires combining a low carrier density and a high mobility. It was believed for a long time that low temperature transport was exclusively dominated by the existence of unscreened Coulomb interactions leading to an insulating behavior at low temperature. However experiments have also shown evidence of superconductivity in carbon nanotubes. We distinguish two fundamentally different physical situations. When carbon nanotubes are connected to superconducting electrodes, they exhibit proximity induced superconductivity with supercurrents which strongly depend on the transmission of the electrodes. On the other hand intrinsic superconductivity was also observed in suspended ropes of carbon nanotubes and recently in doped individual tubes. These experiments indicate the presence of attractive interactions in carbon nanotubes which overcome Coulomb repulsion at low temperature, and enables investigation of superconductivity in a 1D limit never explored before. To cite this article: M. Ferrier et al., C. R. Physique 10 (2009).

Ferrier, M.; Kasumov, A.; Deblock, R.; Guéron, S.; Bouchiat, H.

2009-05-01

392

Method for producing carbon nanotubes  

DOEpatents

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)

2006-02-14

393

Processing, characterization and modeling of carbon nanofiber modified carbon/carbon composites  

NASA Astrophysics Data System (ADS)

Carbon/Carbon (C/C) composites are used in high temperature applications because they exhibit excellent thermomechanical properties. There are several challenges associated with the processing of C/C composites that include long cycle times, formation of closed porosity within fabric woven architecture and carbonization induced cracks that can lead to reduction of mechanical properties. This work addresses various innovative approaches to reduce processing uncertainties and thereby improve thermomechanical properties of C/C by using vapor grown carbon nanofibers (VGCNFs) in conjunction with carbon fabric and precursor phenolic matrix. The different aspects of the proposed research contribute to understanding of the translation of VGCNFs properties in a C/C composite. The specific objectives of the research are; (a) To understand the mechanical properties and microstructural features of phenolic resin precursor with and without modification with VGCNFs; (b) To develop innovative processing concepts that incorporate VGCNFs by spraying them on carbon fabric and/or adding VGCNFs to the phenolic resin precursor; and characterizing the process induced thermal and mechanical properties; and (c) To develop a finite element model to evaluate the thermal stresses developed in the carbonization of carbon/phenolic with and without VGCNFs. Addition of VGCNFs to phenolic resin enhanced the thermal and physical properties in terms of flexure and interlaminar properties, storage modulus and glass transition temperature and lowered the coefficient of thermal expansion. The approaches of spraying VGCNFs on the fabric surface and mixing VGCNFs with the phenolic resin was found to be effective in enhancing mechanical and thermal properties of the resulting C/C composites. Fiber bridging, improved carbon yield and minimization of carbonization-induced damage were the benefits of incorporating VGCNFs in C/C composites. Carbonization induced matrix cracking predicted by the finite element model is consistent with that observed experimentally. The finite element model is supported by a modification of a shear-lag model that describes the load transfer of a crack at the fiber/matrix interface.

Samalot Rivera, Francis J.

394

Carbon dioxide review 1982  

SciTech Connect

The buildup of CO/sub 2/ is a reality, monitored with increasing precision since 1957 and inferred for much earlier dates. A statistical section gives the monitored values to 1980, as well as a review of a long series of measurements made at Mauna Loa by the pioneers of such monitoring, Charles D. Keeling, Robert B. Bacastow, and Timothy P. Whorf. The book discusses internal transport processes in the ocean, of ocean-atmosphere interaction, of the magnitude of forest and soil carbon wastage, of the future course of fossil-fuel consumption. Yet something else emerges, too: if the CO/sub 2/ buildup continues; if the big general circulation models are right about its impact on climate, and if we have not miscalculated the potential role of the oceans, then we face a climatic change in the next century and a half like nothing the post-glacial world, and hence civilized humanity, has seen.

Clark, W.C. (ed.)

1982-01-01

395

Cantilevered carbon nanotube hygrometer  

NASA Astrophysics Data System (ADS)

We investigate the effects of humidity on the vibrations of carbon nanotubes (CNTs) using two types of CNT cantilevers: open-ended and close-ended CNT cantilevers. As the humidity increases, the resonant frequency of the open-ended CNT cantilever decreases due to the adsorption of water molecules onto the CNT tip, whereas that of the close-ended CNT cantilever increases probably due to the change in the viscosity of the air surrounding the CNT cantilever, which is negatively correlated with the humidity of air. Our findings suggest that a close-ended CNT cantilever is more suitable for a quick-response and ultrasensitive hygrometer because it continuously reads the viscosity change of moist air in the vicinity of the CNT.

Kuroyanagi, Toshinori; Terada, Yuki; Takei, Kuniharu; Akita, Seiji; Arie, Takayuki

2014-05-01

396

Sampling Carbon Dioxide  

NSDL National Science Digital Library

In this lab activity, student teams hypothesize which source has a greater becomes CO² concentration: their breath, auto exhaust, or air in the classroom. They test gas samples from each of these sources, plot data, and hypothesize about the respective role engine exhaust and animal respiration play in contemporary climate change. The lab procedures require Bromthymol Blue indicator solution (BTB), household ammonia, vinegar, and balloons. Links to videos supporting the investigations are provided. This activity is supported by a textbook chapter, "How is Carbon Dioxide Measured?," part of the unit, Climate Change, in Global Systems Science (GSS), an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

397

Carbon Monoxide Sensor  

NASA Technical Reports Server (NTRS)

The fuel cell is a system which employs an electrochemical process to convert gases- J such as hydrogen and oxygen directly into electricity. Under NASA sponsorship, GE's Aircraft Equipment Division developed fuel cells to supply electrical power for the Gemini and Biosatellite spacecraft of the sixties and is currently working on advanced fuel cell development. This long-term effort has resulted in a series of spinoff applications using the same general technology for a variety of purposes, among them the recently marketed Dosimeter. The Dosimeter is designed to help users meet safety requirements for industrial atmospheres, as specified by the Occupational Safety and Health Administration and other regulatory agencies. The compact, pocket-sized sensor measures personnel exposure to carbon monoxide and provides both a visual and an audible alarm if the concentration of the gas exceeds present levels. The Dosimeter offers substantial improvement in measuring accuracy over earlier warning indicators.

1978-01-01

398

Total organic carbon analyzer  

NASA Technical Reports Server (NTRS)

The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.

1991-01-01

399

Carbon nanotube electron gun  

NASA Technical Reports Server (NTRS)

An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

2010-01-01

400

Carbon dioxide: atmospheric overload  

SciTech Connect

The level of carbon dioxide in the atmosphere is increasing and may double within the next century. The result of this phenomenon, climatic alterations, will adversely affect crop production, water supplies, and global temperatures. Sources of CO2 include the combustion of fossil fuels, photosynthesis, and the decay of organic matter in soils. The most serious effect of possible climatic changes could occur along the boundaries of arid and semiarid regions. Shifts is precipitation patterns could accelerate the processes of desertification. An increase of 5..cap alpha..C in the average temperature of the top 1000 m of ocean water would raise sea level by 2 m. CO2 releases to the atmosphere can be reduced by controlling emissions from fossil fuel-fired facilities and by careful harvesting of forest regions. (3 photos, 5 references)

Not Available

1980-04-01

401

Carbon nanotube terahertz detector.  

PubMed

Terahertz (THz) technologies are promising for diverse areas such as medicine, bioengineering, astronomy, environmental monitoring, and communications. However, despite decades of worldwide efforts, the THz region of the electromagnetic spectrum still continues to be elusive for solid state technology. Here, we report on the development of a powerless, compact, broadband, flexible, large-area, and polarization-sensitive carbon nanotube THz detector that works at room temperature. The detector is sensitive throughout the entire range of the THz technology gap, with responsivities as high as ?2.5 V/W and polarization ratios as high as ?5:1. Complete thermoelectric and opto-thermal characterization together unambiguously reveal the photothermoelectric origin of the THz photosignal, triggered by plasmonic absorption and collective antenna effects, and suggest that judicious design of thermal management and quantum engineering of Seebeck coefficients will lead to further enhancement of device performance. PMID:24875576

He, Xiaowei; Fujimura, Naoki; Lloyd, J Meagan; Erickson, Kristopher J; Talin, A Alec; Zhang, Qi; Gao, Weilu; Jiang, Qijia; Kawano, Yukio; Hauge, Robert H; Léonard, François; Kono, Junichiro

2014-07-01

402

Total organic carbon analyzer  

NASA Astrophysics Data System (ADS)

The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.

403

Helium diffusion in carbonates  

NASA Astrophysics Data System (ADS)

The abundance and large grain size of carbonate minerals make them a potentially attractive target for 4He thermochronology and 3He cosmogenic dating, although the diffusive properties of helium in carbonates remain poorly understood. This work characterizes helium diffusion in calcite and dolomite to better understand the crystal-chemical factors controlling He transport and retentivity. Slabs of cleaved natural calcite and dolomite, and polished sections of calcite cut parallel or normal to c, were implanted with 3He at 3 MeV with a dose of 5x1015/cm2. Implanted carbonates were heated in 1-atm furnaces, and 3He distributions following diffusion anneals were profiled with Nuclear Reaction Analysis using the reaction 3He(d,p)4He. For 3He transport normal to cleavage surfaces in calcite, we obtain the following Arrhenius relation over the temperature range 78-300°C: Dcalcite = 9.0x10-9exp(-55 × 6 kJ mol-1/RT) m2sec-1. Diffusion in calcite exhibits marked anisotropy, with diffusion parallel to c about two orders of magnitude slower than diffusion normal to cleavage faces. He diffusivities for transport normal to the c-axis are similar in value to those normal to cleavage surfaces. Our findings are broadly consistent with helium diffusivities from step-heating measurements of calcite by Copeland et al. (2007); these bulk degassing data may reflect varying effects of diffusional anisotropy. Helium diffusion normal to cleavage surfaces in dolomite is significantly slower than diffusion in calcite, and has a much higher activation energy for diffusion. For dolomite, we obtain the following Arrhenius relation for He diffusion over the temperature range 150-400°C: Ddolomite = 9.0x10-8exp(-92 × 9 kJ mol-1/RT) m2sec-1. The role of crystallographic structure in influencing these differences among diffusivities was evaluated using the maximum aperture approach of Cherniak and Watson (2011), in which crystallographic structures are sectioned along possible diffusion directions and the maximum interstitial apertures in each 'slice' in the structure are identified. Preliminary results show that observed differences in diffusivities are consistent with the size of the smallest maximum aperture along each diffusion direction. In calcite, the smallest maximum apertures are ~0.92 and ~0.66 angstroms for cleavage-normal and c-axis parallel directions respectively. In dolomite, the smallest maximum aperture is ~0.78 angstroms for the cleavage normal direction. Work is in progress on characterizing helium diffusion for other orientations in dolomite, and in other carbonates, including aragonite and magnesite, and in implementing these diffusion findings in the interpretation and modeling of bulk volume diffusion in heterogeneous calcite crystals common in many geologic applications. Copeland et al. (2007) GCA 71, 4488-4511 Cherniak and Watson, (2011) Chem. Geo. 288, 149-161

Amidon, W. H.; Cherniak, D. J.; Watson, E. B.; Hobbs, D.

2013-12-01

404

Crystallization in Carbon Nanostructures  

NASA Astrophysics Data System (ADS)

We investigate ground state configurations for atomic potentials including both two- and three-body nearest-neighbor interaction terms. The aim is to prove that such potentials may describe crystallization in carbon nanostructures such as graphene, nanotubes, and fullerenes. We give conditions in order to prove that planar energy minimizers are necessarily honeycomb, namely graphene patches. Moreover, we provide an explicit formula for the ground state energy which exactly quantifies the lower-order surface energy contribution. This allows us to give some description of the geometry of ground states. By recasting the minimization problem in three-space dimensions, we prove that ground states are necessarily nonplanar and, in particular, rolled-up structures like nanotubes are energetically favorable. Eventually, we check that the C20 and C60 fullerenes are strict local minimizers, hence stable.

Mainini, Edoardo; Stefanelli, Ulisse

2014-06-01

405

Dispersible carbon nanotubes.  

PubMed

A method is proposed to produce nanoparticles dispersible and recyclable in any class of solvents, and the concept is illustrated with the carbon nanotubes. Classically, dispersions of CNTs can be achieved through steric stabilization induced by adsorbed or grafted polymer chains. Yet, the surface modification of CNTs surfaces is irreversible, and the chemical nature of the polymer chains imposes the range of solvents in which CNTs can be dispersed. To address this limitation, supramolecular bonds can be used to attach and to detach polymer chains from the surface of CNTs. The reversibility of supramolecular bonds offers an easy way to recycle CNTs as well as the possibility to disperse the same functional CNTs in any type of solvent, by simply adapting the chemical nature of the stabilizing chains to the dispersing medium. The concept of supramolecular functionalization can be applied to other particles, for example, silica or metal oxides, as well as to dispersing in polymer melts, films or coatings. PMID:24458908

Soulié-Ziakovic, Corinne; Nicolaÿ, Renaud; Prevoteau, Alexandre; Leibler, Ludwik

2014-01-27

406

Orbiting Carbon Observatory Science Writers' Guide.  

National Technical Information Service (NTIS)

The Orbiting Carbon Observatory is the latest mission in NASAs ongoing study of the global carbon cycle. It is the first spacecraft dedicated to studying atmospheric carbon dioxide, the most significant human-produced greenhouse gas and the principal huma...

A. Buis G. Cook-Anderson K. Hansen R. Sullivant

2008-01-01

407

21 CFR 582.1619 - Potassium carbonate.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 2013-04-01 false Potassium carbonate. 582.1619 Section 582.1619...General Purpose Food Additives § 582.1619 Potassium carbonate. (a) Product. Potassium carbonate. (b) Conditions of use....

2013-04-01

408

21 CFR 582.1425 - Magnesium carbonate.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 2013-04-01 false Magnesium carbonate. 582.1425 Section 582.1425...General Purpose Food Additives § 582.1425 Magnesium carbonate. (a) Product. Magnesium carbonate. (b) Conditions of use....

2013-04-01

409

Carbon Sequestration Project Portfolio, FY 2005.  

National Technical Information Service (NTIS)

The United States Department of Energy's (DOE) Carbon Sequestration Program continues to make progress toward its goals of lowering the cost of carbon dioxide (CO(sub 2)) capture and ensuring permanent and safe carbon storage. As sequestration technology ...

2005-01-01

410

The Carbon Crisis in 90 Seconds  

NSDL National Science Digital Library

This video features a short animated sequence that illustrates the difference between young and old carbon released into the atmosphere from the consumption of food (young carbon) and the burning of fossil fuels (old carbon).

Nasa

411

Activated Carbon Fibers for Artificial Kidney Devices.  

National Technical Information Service (NTIS)

Activated carbon fibers were made by wet-spinning a dispersion of powdered activated carbon in hydroxyethylcellulose solution. The resulting monofilament had 70% (dry basis) of activated carbon encapsulated in a water-swollen cellulosic binder that was qu...

T. A. Davis

1973-01-01

412

Carbon Anode Materials  

NASA Astrophysics Data System (ADS)

Accompanying the impressive progress of human society, energy storage technologies become evermore urgent. Among the broad categories of energy sources, batteries or cells are the devices that successfully convert chemical energy into electrical energy. Lithium-based batteries stand out in the big family of batteries mainly because of their high-energy density, which comes from the fact that lithium is the most electropositive as well as the lightest metal. However, lithium dendrite growth after repeated charge-discharge cycles easily will lead to short-circuit of the cells and an explosion hazard. Substituting lithium metal for alloys with aluminum, silicon, zinc, and so forth could solve the dendrite growth problem.1 Nevertheless, the lithium storage capacity of alloys drops down quickly after merely several charge-discharge cycles because the big volume change causes great stress in alloy crystal lattice, and thus gives rise to cracking and crumbling of the alloy particles. Alternatively, Sony Corporation succeeded in discovering the highly reversible, low-voltage anode, carbonaceous material and commercialized the C/LiCoO2 rocking chair cells in the early 1990s.2 Figure 3.1 schematically shows the charge-discharge process for reversible lithium storage in carbon. By the application of a lithiated carbon in place of a lithium metal electrode, any lithium metal plating process and the conditions for the growth of irregular dendritic lithium could be considerably eliminated, which shows promise for reducing the chances of shorting and overheating of the batteries. This kind of lithium-ion battery, which possessed a working voltage as high as 3.6 V and gravimetric energy densities between 120 and 150 Wh/kg, rapidly found applications in high-performance portable electronic devices. Thus the research on reversible lithium storage in carbonaceous materials became very popular in the battery community worldwide.

Ogumi, Zempachi; Wang, Hongyu

413

Carbonate formation on bioactive glasses.  

PubMed

The system termed 58S is a sol-gel-synthesized bioactive glass composed of SiO2, CaO, and P2O5, used in medicine as bone prosthetic because, when immersed in a physiological fluid, a layer of hydroxycarbonate apatite is formed on its surface. The mechanism of bioactive glass 58S carbonation was studied in the vacuum by means of in-situ FTIR spectroscopy with the use of CO2, H2O, and CD3CN as probe molecules. The study in the vacuum was necessary to identify both the molecules specifically involved in the carbonation process and the type of carbonates formed. Bioactive glass 58S was compared to a Ca-doped silica and to CaO. On CaO, ionic carbonates could form by contact with CO2 alone, whereas on 58S and on Ca-doped silica carbonation occurred only if both CO2 and an excess of H2O were present on the sample. The function of H2O was not only to block surface cationic sites, so that CO2 could not manifest its Lewis base behavior, but also to form a liquid-like (mono)layer that allowed the formation of carbonate ions. The presence of H2O is also supposed to promote Ca2+ migration from the bulk to the surface. Carbonates formed at the surface of CaO and of Ca-bearing silicas (thus including bioactive glasses) are of the same type, but are produced through two different mechanisms. The finding that a water excess is necessary to start heavy carbonation on bioactive glasses seemed to imply that the mechanism leading to in-situ carbonation simulates, in a simplified and easy-to-reproduce system, what happens both in solution, when carbonates are incorporated in the apatite layer, and during sample shelf-aging. PMID:15248726

Cerruti, Marta; Morterra, Claudio

2004-07-20

414

Carbon Nanocomposite Based on Carbon Nanotubes and Ultrananocrystalline Diamond  

NASA Astrophysics Data System (ADS)

Carbon-based nanostructured materials exhibit many interesting properties that are dictated by the many different bonding configurations available to carbon. Two typical examples are carbon nanotubes (CNTs) and ultrananocrystalline diamond (UNCD), with the former being sp2 bonded carbon and latter being sp3 bonded carbon. Recent advances in micro and nanofabrication techniques have made possible the development of microscale and perhaps even nanoscale devices that capitalize on the many intrinsic strengths of these carbon-based materials. The focus of our study has been to prepare CNTs/UNCD composites. We demonstrate in this presentation the simultaneous growth of carbon nanotubes and diamond with the Ar/CH4 (99:1) plasma chemistry. The relative fraction of UNCD and CNTs was controlled by adjusting the relative density of diamond seeds and catalyst particles for the nucleation of UNCD and CNTs. Different methods, including Scanning Electron Microscopy (SEM), Raman Spectroscopy, Transmission Electron Microscopy (TEM) and Near Edge X-ray Absorption Fine Structure (NEXAFS) were used to characterize the composite nanostructures. The field emission and electrochemical properties of the composites were investigated. All these studies provide guidance to further explore the application of the CNTs/UNCD composites as field emitters and novel biosensors.

Xiao, Xingcheng; Wang, Jian; Auciello, Orlando; Carlisle, John A.

2004-03-01

415

Lightweight Carbon-Carbon High-Temperature Space Radiator  

NASA Technical Reports Server (NTRS)

A document summarizes the development of a carbon-carbon composite radiator for dissipating waste heat from a spacecraft nuclear reactor. The radiator is to be bonded to metal heat pipes and to operate in conjunction with them at a temperature approximately between 500 and 1,000 K. A goal of this development is to reduce the average areal mass density of a radiator to about 2 kg/m(exp 2) from the current value of approximately 10 kg/m(exp 2) characteristic of spacecraft radiators made largely of metals. Accomplishments thus far include: (1) bonding of metal tubes to carbon-carbon material by a carbonization process that includes heating to a temperature of 620 C; (2) verification of the thermal and mechanical integrity of the bonds through pressure-cycling, axial-shear, and bending tests; and (3) construction and testing of two prototype heat-pipe/carbon-carbon-radiator units having different radiator areas, numbers of heat pipes, and areal mass densities. On the basis of the results achieved thus far, it is estimated that optimization of design could yield an areal mass density of 2.2 kg/m (exp 2) close to the goal of 2 kg/m(exp 2).

Miller, W.O.; Shih, Wei

2008-01-01

416

Reduction of carbon dioxide on modified glassy carbon electrodes  

SciTech Connect

Carbon dioxide in the atmosphere gives an important contribution to environmental pollution due to the progressive increase of its production everywhere from many sources. It is believed now that the capacity of the biosphere, due to absorption and transformation of CO{sub 2}, has been considerably exceeded and many attempts to overcome this problem by different ways, have been successful. Electrochemical reduction seems to be an appropriate route for carbon dioxide consumption and its transformation to useful compounds. Electrochemical reduction of carbon dioxide on glassy carbon (GC) was studied by applying different potential regimes and monitoring the effect of the electrode surface conditioning, as well as the nature of supporting electrolyte, upon the nature of the reaction. In the case of constant potential electrolyses, a rapid decay of the cathodic current was observed, while application of a suitable pulse program to the working electrode, in addition to the ultrasonic cleaning of the surface, allowed completion of the reaction without premature current downfall. Modification of the electrode surface, by applying potential pulses, caused a decrease of the reduction potential of CO{sub 2} on glassy carbon. High yields in carbon monoxide and methanol were obtained in these media, with the highest value obtained for methanol in sodium chloride and carbon monoxide in ammonium oxalate.

Hernandez, R.M.; Marquez, J.; Marquez, O.P.; Choy, M.; Ovalles, C.; Garcia, J.J.; Scharifker, B.

1999-11-01

417

Four advances in carbon-carbon materials technology  

NASA Technical Reports Server (NTRS)

Carbon-carbon composites are a specialty class of materials having many unique properties making these composites attractive for a variety of demanding engineering applications. Chief among these properties are exceptional retention of mechanical properties at temperatures as high as 4000 F, excellent creep resistance, and low density (1.6 to 1.8 g/cu cm). Although carbon-carbon composites are currently in service in a variety of applications, much development work remains to be accomplished before these materials can be considered to be fully mature, realizing their full potential. Four recent technology advances holding particular promise for overcoming current barriers to the wide-spread commercialization of carbon-carbon composites are described. These advances are: markedly improved interlaminar strengths (more than doubled) of two dimensional composites achieved by whiskerization of the fabric reinforcing plies, simultaneously improved oxidation resistance and mechanical properties achieved by the incorporation of matrix-phase oxidation inhibitors based on carborane chemistry, improved oxidation resistance achieved by compositionally graded oxidation protective coatings, and markedly reduced processing times (hours as opposed to weeks or months) accomplished through a novel process of carbon infiltration and coatings deposition based on the use of liquid-phase precursor materials.

Maahs, Howard G.; Vaughn, Wallace L.; Kowbel, Witold

1994-01-01

418

Carbon Flux Explorer observations of ocean carbon sedimentation  

NASA Astrophysics Data System (ADS)

The strength of natural biotic organic carbon sedimentation from the base of sunlit zone of the ocean is estimated to be 10 Pg C/y globally. This biological sequestration of carbon to deeper waters plays a key role in the atmophere/ocean carbon balance. It is impossible to predict whether the ocean biological carbon pump will strengthen or weaken in the face of climate change and ocean acidification because there are scant observations of the sinking carbon flux and remineralization in the upper 1000 m. We report progress on the development and deployment of the fully robotic and autonomous Ocean Carbon Flux Explorer (CFE) which is designed to follow hourly variations of carbon sedimentation for seasons at depths to 1500 m. The CFE relays observations to shore in real time via Iridium satellite links. The Carbon Flux Explorer is the integration of the Scripps Sounding Oceanographic Lagrangian Observer (SOLO) with the LBNL/UC Berkeley Optical Sedimentation Recorder (OSR). The OSR intercepts sinking particles and images them using dark field, transmitted, and transmitted cross polarized modes of illumination. OSR's modified to collect samples have been deployed to enable translation image data on particle albedo, optical density, and birefringence to carbon units. Our aim is fully autonomous operations in 2012. In this progress update, we report highlights of CFE deployments in the Santa Catalina Basin (October 2010, May 2011) and Santa Cruz Basin (May 2011), and California Current waters (August through September 2011). In many cases CFE data shows order of magnitude variation of particle sedimentation on diurnal time scales, a view of sedimentation here-to-fore not attained.

Bishop, J. K.; Wood, T.

2011-12-01

419

Carbon sequestration in European croplands.  

PubMed

The Marrakech Accords allow biospheric carbon sinks and sources to be included in attempts to meet emission reduction targets for the first commitment period of the Kyoto Protocol. Forest management, cropland management, grazing land management, and re-vegetation are allowable activities under Article 3.4 of the Kyoto Protocol. Soil carbon sinks (and sources) can, therefore, be included under these activities. Croplands are estimated to be the largest biospheric source of carbon lost to the atmosphere in Europe each year, but the cropland estimate is the most uncertain among all land-use types. It is estimated that European croplands (for Europe as far east as the Urals) lose 300 Tg (C) per year, with the mean figure for the European Union estimated to be 78 Tg (C) per year (with one SD=37). National estimates for EU countries are of a similar order of magnitude on a per-area basis. There is significant potential within Europe to decrease the flux of carbon to the atmosphere from cropland, and for cropland management to sequester soil carbon, relative to the amount of carbon stored in cropland soils at present. The biological potential for carbon storage in European (EU 15) cropland is of the order of 90-120 Tg (C) per year, with a range of options available that include reduced and zero tillage, set-aside, perennial crops, deep rooting crops, more efficient use of organic amendments (animal manure, sewage sludge, cereal straw, compost), improved rotations, irrigation, bioenergy crops, extensification, organic farming, and conversion of arable land to grassland or woodland. The sequestration potential, considering only constraints on land use, amounts of raw materials and available land, is up to 45 Tg (C) per year. The realistic potential and the conservative achievable potentials may be considerably lower than the biological potential because of socioeconomic and other constraints, with a realistically achievable potential estimated to be about 20% of the biological potential. As with other carbon sequestration options, potential impacts of non-CO, trace gases also need to be factored in. If carbon sequestration in croplands is to be used in helping to meet emission reduction targets for the first commitment period of the Kyoto Protocol, the changes in soil carbon must be measurable and verifiable. Changes in soil carbon can be difficult to measure over a 5-year commitment period, and this has implications for Kyoto accounting and verification. Currently, most countries can hope to achieve only a low level of verifiability during the first commitment period, whereas those with the best-developed national carbon accounting systems will be able to deliver an intermediate level of verifiability. Very stringent definitions of verifiability would require verification that would be prohibitively expensive for any country. There is considerable potential in European croplands to reduce carbon fluxes to the atmosphere and to sequester carbon iri the soil, but carbon sequestration in soil has a finite potential and is non-permanent. Given that carbon sequestration may also be difficult to measure and verify, soil carbon sequestration is a riskier long-term strategy for climate mitigation than direct reduction of carbon emissions. However, improved agricultural management often has a range of other environmental and economic benefits in addition to climate mitigation potential, and this may make attempts to improve soil carbon storage attractive as part of integrated sustainability policies. PMID:17633030

Smith, Pete; Falloon, Pete

2005-01-01

420

Ureilite Carbon and mg Number  

NASA Astrophysics Data System (ADS)

Ureilites are carbon-bearing ultramafic achondrites composed primarily of olivine and pyroxene with intergranular fine-grained metal, sulfides, and silicates. Carbon (up to 6.5 wt%) is either amorphous or present as graphite, lonsdaleite, and/or diamond. It has been shown that carbon-silicate redox (i.e. "smelting") reactions are responsible for the positive correlation between modal percent pigeonite and mg# and for the negative FeO-MnO trend seen in the mineral and bulk compositions of ureilites. Carbon redox reactions are strongly exothermic and pressure dependent; so ureilites with the largest mg# are the most reduced, experienced the highest temperatures, and formed at the lowest pressures, i.e. near the surface of the ureilite parent body. Ureilites with the largest mg# have the smallest ? 18O and the largest ? 17O. To further investigate possible relationships, we performed carbon isotope and electron probe measurements on a suite of 27 ureilites in order to see the type of correlation that exists between mg# and carbon. Mg#s of olivine cores, carbon contents, and ? 13C data were taken from this study and the literature, and averaged. Polymict ureilites were not considered. A well-defined negative correlation is observed between the mg# of olivine cores and ? 17O. A less well-defined negative correlation may exist between mg# of olivine cores and ? 13C, but there is substantial scatter in the data. However, a well-defined negative correlation exists between mg# of olivine rims and ? 13C. At first glance, this trend is unexpected: if ureilites with the largest mg# experienced the greatest amount of reduction, they should have the largest ? 13C and the correlation between mg# and ? 13C should be positive. A plot of carbon content versus ? 13C seems to show a general trend: the smaller the carbon content, the heavier is the carbon. This general trend is exactly what one would expect if smelting has affected the ureilite parent body: the more C is consumed during smelting, the heavier the residue become. However, mg#s do not support this interpretation: ureilites with the largest mg# have the smallest carbon content and the smallest ? 13C, while ureilites with the largest mg# have the opposite. To explain this apparent contradiction, one needs to consider that ureilites have experienced two reducing events. The first one is recorded in the cores of the olivine crystals while the second is seen in the strongly reduced rims. During the heating of the ureilite parent body, the olivine cores first equilibrated with the carbon and their mg# were fixed according to their depth: the deepest olivine experienced little reduction, had low mg#, relatively light carbon (? 13C < -10 ‰ ) and high carbon content (about 7-8 wt%); the shallowest olivines experienced the greatest reduction, resulting in high mg#, relatively light carbon (? 13C < -8 to -10‰ ) and low carbon content (about 4 wt%). The second reducing event was marked by a sudden drop in pressure (possibly due to an impact that disrupted the parent body). During this event, olivines that formed at depth were now strongly reduced along their rims (the cores preserved their initial mg#), their carbon became heavier (? 13C > -8‰ ) and their carbon content decreased (below about 4 wt%). On the other hand, olivines that formed initially near the surface of the parent body did not experience much change in terms of mg#, ? 13C, and carbon content.

Hudon, P.; Romanek, C.; Paddock, L.; Mittlefehldt, D. W.

2004-05-01

421

Hierarchical carbon nanostructure design: ultra-long carbon nanofibers decorated with carbon nanotubes  

NASA Astrophysics Data System (ADS)

Hierarchical carbon nanostructures based on ultra-long carbon nanofibers (CNF) decorated with carbon nanotubes (CNT) have been prepared using plasma processes. The nickel/carbon composite nanofibers, used as a support for the growth of CNT, were deposited on nanopatterned silicon substrate by a hybrid plasma process, combining magnetron sputtering and plasma-enhanced chemical vapor deposition (PECVD). Transmission electron microscopy revealed the presence of spherical nanoparticles randomly dispersed within the carbon nanofibers. The nickel nanoparticles have been used as a catalyst to initiate the growth of CNT by PECVD at 600 °C. After the growth of CNT onto the ultra-long CNF, SEM imaging revealed the formation of hierarchical carbon nanostructures which consist of CNF sheathed with CNTs. Furthermore, we demonstrate that reducing the growth temperature of CNT to less than 500 °C leads to the formation of carbon nanowalls on the CNF instead of CNT. This simple fabrication method allows an easy preparation of hierarchical carbon nanostructures over a large surface area, as well as a simple manipulation of such material in order to integrate it into nanodevices.

El Mel, A. A.; Achour, A.; Xu, W.; Choi, C. H.; Gautron, E.; Angleraud, B.; Granier, A.; Le Brizoual, L.; Djouadi, M. A.; Tessier, P. Y.

2011-10-01

422

Spectral evidence for carbonates on Mars: Hydrous carbonates  

NASA Technical Reports Server (NTRS)

Although many of the spectral features of the Martian samples studied are not unique mineralogical indicators, much of the current spectral data is consistent with (possibly abundant) hydrous carbonates on the surface of Mars. The absorption features in the measured samples were quite weak compared with those of anhydrous carbonates. The weak features imply that significantly more hydrous carbonates can be incorporated onto the surface before becoming spectrally evident; however, exact limits have yet to be determined. The stability of these materials in the Martian environment is not known, but their formation and occurrence in low temperature terrestrial environments makes them appealing candidates for weathering products on Mars.

Calvin, W. M.; King, T. V. V.

1991-01-01

423

Nanophase Carbonates on Mars: Implications for Carbonate Formation and Habitability  

NASA Technical Reports Server (NTRS)

Despite having an atmosphere composed primarily of CO2 and evidence for abundant water in the past, carbonate minerals have only been discovered in small amounts in martian dust [1], in outcrops of very limited extent [2, 3], in soils in the Northern Plains (the landing site of the 2007 Phoenix Mars Scout Mission) [4] and may have recently been detected in aeolian material and drilled and powdered sedimentary rock in Gale Crater (the Mars Science Laboratory [MSL] landing site) [5]. Thermal analysis of martian soils by instruments on Phoenix and MSL has demonstrated a release of CO2 at temperatures as low as 250-300 degC, much lower than the traditional decomposition temperatures of calcium or magnesium carbonates. Thermal decomposition temperature can depend on a number of factors such as instrument pressure and ramp rate, and sample particle size [6]. However, if the CO2 released at low temperatures is from carbonates, small particle size is the only effect that could have such a large impact on decomposition temperature, implying the presence of extremely fine-grained (i.e., "nanophase" or clay-sized) carbonates. We hypothesize that this lower temperature release is the signature of small particle-sized (clay-sized) carbonates formed by the weathering of primary minerals in dust or soils through interactions with atmospheric water and carbon dioxide and that this process may persist under current martian conditions. Preliminary work has shown that clay-sized carbonate grains can decompose at much lower temperatures than previously thought. The first work took carbonate, decomposed it to CaO, then flowed CO2 over these samples held at temperatures >100 degC to reform carbonates. Thermal analysis confirmed that carbonates were indeed formed and transmission electron microsopy was used to determine crystal sized were on the order of 10 nm. The next step used minerals such as diopside and wollastonite that were sealed in a glass tube with a CO2 and H2O source. After reacting these materials for a number of hours, thermal analysis demonstrated the formations of carbonates that decomposed at temperatures as low as 500 degC [7]. Further work is underway to carry out the weathering process under more Mars-like conditions (low pressure and low temperature) to determine if the carbonate decomposition temperature can be shifted to even lower temperatures, consistent with what has been detected by thermal analysis instruments on Mars.

Archer, P. Douglas, Jr.; Lauer, H. Vern; Ming, Douglas W.; Niles, Paul B.; Morris, Richard V.; Rampe, Elizabeth B.; Sutter, Brad

2014-01-01

424

The fabrication of artifacts out of glassy carbon and carbon-fiber-reinforced carbon for biomedical applications.  

PubMed

Polymeric carbons are produced by the carbonization of a wide range of organic polymeric systems. We have concentrated on the fabrication of two types of polymeric carbons, glassy carbon and carbon-fiber-reinforced carbon (CFRC), both involving phenolic resin precursors. We describe herein the technology which enables us to make dental implants and heart valves out of glassy carbon. We also show how carbon-fiber-reinforced carbon can be made in the form of rods and plates for orthopedic use and molded before firing to produce complex, rigid, individually sculptured shapes suitable for maxillofacial bone replacement. The mechanical properties will be discussed in relation to the structure of these various forms of polymeric carbon. The main purpose of the work is to show that the technology of polymeric-carbon manufacture is essentially simple and the manufacturing process is readily carried out in laboratories which have already been equipped to fabricate standard dental prostheses. PMID:571441

Jenkins, G M; Grigson, C J

1979-05-01

425

Ocean uptake of carbon dioxide  

SciTech Connect

Factors controlling the capacity of the ocean for taking up anthropogenic C0{sup 2} include carbon chemistry, distribution of alkalinity, pCO{sup 2} and total concentration of dissolved C0{sup 2}, sea-air pCO{sup 2} difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0{sup 2} uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0{sup 2} from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0{sup 2} fertilization is a potential candidate for such missing carbon sinks.

Peng, Tsung-Hung [Oak Ridge National Lab., TN (United States); Takahashi, Taro [Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory

1993-06-01

426

Ocean uptake of carbon dioxide  

SciTech Connect

Factors controlling the capacity of the ocean for taking up anthropogenic C0[sup 2] include carbon chemistry, distribution of alkalinity, pCO[sup 2] and total concentration of dissolved C0[sup 2], sea-air pCO[sup 2] difference, gas exchange rate across the sea-air interface, biological carbon pump, ocean water circulation and mixing, and dissolution of carbonate in deep sea sediments. A general review of these processes is given and models of ocean-atmosphere system based on our understanding of these regulating processes axe used to estimate the magnitude of C0[sup 2] uptake by the ocean. We conclude that the ocean can absorb up to 35% of the fossil fuel emission. Direct measurements show that 55% Of C0[sup 2] from fossil fuel burning remains in the atmosphere. The remaining 10% is not accounted for by atmospheric increases and ocean uptake. In addition, it is estimated that an amount equivalent to 30% of recent annual fossil fuel emissions is released into the atmosphere as a result of deforestation and farming. To balance global carbon budget, a sizable carbon sink besides the ocean is needed. Storage of carbon in terrestrial biosphere as a result of C0[sup 2] fertilization is a potential candidate for such missing carbon sinks.

Peng, Tsung-Hung (Oak Ridge National Lab., TN (United States)); Takahashi, Taro (Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory)

1993-01-01

427

Gas permeability of carbon aerogels  

SciTech Connect

Carbon aerogels are synthesized via the aqueous polycondensation of resorcinol with formaldehyde, followed by supercritical drying and subsequent pyrolysis at 1050 [degree]C. As a result of their interconnected porosity, ultrafine cell/pore size, and high surface area, carbon aerogels have many potential applications such as supercapacitors, battery electrodes, catalyst supports, and gas filters. The performance of carbon aerogels in the latter two applications depends on the permeability or gas flow conductance in these materials. By measuring the pressure differential across a thin specimen and the nitrogen gas flow rate in the viscous regime, the permeability of carbon aerogels was calculated from equations based upon Darcy's law. Our measurements show that carbon aerogels have permeabilities on the order of 10[sup [minus]12] to 10[sup [minus]10] cm[sup 2] over the density range from 0.05--0.44 g/cm[sup 3]. Like many other aerogel properties, the permeability of carbon aerogels follows a power law relationship with density, reflecting differences in the average mesopore size. Comparing the results from this study with the permeability of silica aerogels reported by other workers, we found that the permeability of aerogels is governed by a simple universal flow equation. This paper discusses the relationship between permeability, pore size, and density in carbon aerogels.

Kong, F.; LeMay, J.D.; Hulsey, S.S.; Alviso, C.T.; Pekala, R.W. (Chemistry and Materials Science Department, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States))

1993-12-01

428

TYPE Ia SUPERNOVA CARBON FOOTPRINTS  

SciTech Connect

We present convincing evidence of unburned carbon at photospheric velocities in new observations of five Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 days relative to maximum. Detections are based on the presence of relatively strong C II {lambda}6580 absorption 'notches' in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the five SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibit high-velocity (v > 20, 000 km s{sup -1}) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broadband light curve/color behavior: three of the five have relatively narrow light curves but also blue colors and a fourth may be a dust-reddened member of this family. Accounting for signal to noise and phase, we estimate that 22{sup +10}{sub -6%} of SNe Ia exhibit spectroscopic C II signatures as late as -5 days with respect to maximum. We place these new objects in the context of previously recognized carbon-positive SNe Ia and consider reasonable scenarios seeking to explain a physical connection between light curve properties and the presence of photospheric carbon. We also examine the detailed evolution of the detected carbon signatures and the surrounding wavelength regions to shed light on the distribution of carbon in the ejecta. Our ability to reconstruct the C II {lambda}6580 feature in detail under the assumption of purely spherical symmetry casts doubt on a 'carbon blobs' hypothesis, but does not rule out all asymmetric models. A low volume filling factor for carbon, combined with line-of-sight effects, seems unlikely to explain the scarcity of detected carbon in SNe Ia by itself.

Thomas, R. C.; Nugent, P. [Computational Cosmology Center, Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road MS 50B-4206, Berkeley, CA 94611 (United States); Aldering, G.; Aragon, C.; Bailey, S.; Childress, M.; Fakhouri, H. K.; Hsiao, E. Y.; Loken, S. [Physics Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Antilogus, P.; Bongard, S.; Canto, A. [Laboratoire de Physique Nucleaire et des Hautes Energies, Universite Pierre et Marie Curie Paris 6, Universite Paris Diderot Paris 7, CNRS-IN2P3, 4 place Jussieu, 75252 Paris Cedex 05 (France); Baltay, C. [Department of Physics, Yale University, New Haven, CT 06250-8121 (United States); Buton, C.; Kerschhaggl, M.; Kowalski, M.; Paech, K. [Physikalisches Institut, Universitaet Bonn, Nussallee 12, 53115 Bonn (Germany); Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622 Lyon (France); and others

2011-12-10

429

Type Ia Supernova Carbon Footprints  

NASA Astrophysics Data System (ADS)

We present convincing evidence of unburned carbon at photospheric velocities in new observations of five Type Ia supernovae (SNe Ia) obtained by the Nearby Supernova Factory. These SNe are identified by examining 346 spectra from 124 SNe obtained before +2.5 days relative to maximum. Detections are based on the presence of relatively strong C II ?6580 absorption "notches" in multiple spectra of each SN, aided by automated fitting with the SYNAPPS code. Four of the five SNe in question are otherwise spectroscopically unremarkable, with ions and ejection velocities typical of SNe Ia, but spectra of the fifth exhibit high-velocity (v > 20, 000 km s-1) Si II and Ca II features. On the other hand, the light curve properties are preferentially grouped, strongly suggesting a connection between carbon-positivity and broadband light curve/color behavior: three of the five have relatively narrow light curves but also blue colors and a fourth may be a dust-reddened member of this family. Accounting for signal to noise and phase, we estimate that 22+10 - 6% of SNe Ia exhibit spectroscopic C II signatures as late as -5 days with respect to maximum. We place these new objects in the context of previously recognized carbon-positive SNe Ia and consider reasonable scenarios seeking to explain a physical connection between light curve properties and the presence of photospheric carbon. We also examine the detailed evolution of the detected carbon signatures and the surrounding wavelength regions to shed light on the distribution of carbon in the ejecta. Our ability to reconstruct the C II ?6580 feature in detail under the assumption of purely spherical symmetry casts doubt on a "carbon blobs" hypothesis, but does not rule out all asymmetric models. A low volume filling factor for carbon, combined with line-of-sight effects, seems unlikely to explain the scarcity of detected carbon in SNe Ia by itself.

Thomas, R. C.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Gangler, E.; Hsiao, E. Y.; Kerschhaggl, M.; Kowalski, M.; Loken, S.; Nugent, P.; Paech, K.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Rubin, D.; Runge, K.; Scalzo, R.; Smadja, G.; Tao, C.; Weaver, B. A.; Wu, C.; Brown, P. J.; Milne, P. A.; Nearby Supernova Factory

2011-12-01

430

Carbon-carbon composites: Emerging materials for hypersonic flight  

NASA Technical Reports Server (NTRS)

An emerging class of high temperature materials called carbon-carbon composites are being developed to help make advanced aerospace flight become a reality. Because of the high temperature strength and low density of carbon-carbon composites, aerospace engineers would like to use these materials in even more advanced applications. One application of considerable interest is as the structure of the aerospace vehicle itself rather than simply as a protective heat shield as on Space Shuttle. But suitable forms of these materials have yet to be developed. If this development can be successfully accomplished, advanced aerospace vehicles such as the National Aero-Space Plane (NASP) and other hypersonic vehicles will be closer to becoming a reality. A brief definition is given of C-C composites. Fabrication problems and oxidation protection concepts are examined. Applications of C-C composites in the Space Shuttle and in advanced hypersonic vehicles as well as other applications are briefly discussed.

Maahs, Howard G.

1989-01-01

431

Carbon films produced from ionic liquid carbon precursors  

DOEpatents

The invention is directed to a method for producing a film of porous carbon, the method comprising carbonizing a film of an ionic liquid, wherein the ionic liquid has the general formula (X.sup.+a).sub.x(Y.sup.-b).sub.y, wherein the variables a and b are, independently, non-zero integers, and the subscript variables x and y are, independently, non-zero integers, such that ax=by, and at least one of X.sup.+ and Y.sup.- possesses at least one carbon-nitrogen unsaturated bond. The invention is also directed to a composition comprising a porous carbon film possessing a nitrogen content of at least 10 atom %.

Dai, Sheng; Luo, Huimin; Lee, Je Seung

2013-11-05

432

Current and relic carbon using natural abundance carbon-13  

SciTech Connect

The role of agricultural practices on soil carbon (C) dynamics is critical to improved soil management. The main objective was to examine the C interactions resulting from crop changes under different tillage and residue treatments.

layse,MF; Clapp,CE; Allmaras,RR; Linden,D.R; Molina, JAE.; Copeland,SM; Dowdy,RH

2002-05-01

433

Capacitive, deionization with carbon aerogel electrodes: Carbonate, sulfate, and phosphate.  

National Technical Information Service (NTIS)

A process for the capacitive deionization (CDI) of water with a stack of carbon aerogel electrodes has been developed by Lawrence Livermore National Laboratory. Unlike ion exchange, electricity is used instead of chemicals for regeneration of the system. ...

J. C. Farmer D. V. Fix G. V. Mack R. W. Pekala J. F. Poco

1995-01-01

434

Carbon dioxide solubility and carbon isotope fractionation in basaltic melt  

SciTech Connect

Carbon dioxide solubility and isotope fractionation data for a MORB composition at 1,200-1,400C and 5-20 kbar have been obtained using piston-cylinder apparatus and stepped-heating mass spectrometry. Carbon dioxide solubility in basalt melt at 5, 10 and 20 kbar is 0.15-0.17%, 0.45-0.51%, and 1.49%, respectively. Values for {Delta}Co{sub 2}(vap) - CO 2/3{sup {minus}} (basalt melt), obtained from the difference between the isotopic compositions for coexisting vapor and melt, vary from 1.8% to 2.2%. A review of measured and estimated values for carbon isotope fractionation between CO{sub 2} vapor and carbon dissolved in basic melts shows variation from 1.8% to 4.6%. Results of this study and other considerations favor relatively small equilibrium CO{sub 2} vapor melt fractionation factors around 2%.

Mattey, D.P. (Univ. of London, Egham Hill (United Kingdom) Univ. of Tasmania, Hobart (Australia))

1991-11-01

435

Carbon Dioxide Research Conference: Carbon Dioxide, Science and Consensus.  

National Technical Information Service (NTIS)

The DOE program focuses on three areas each of which requires more research before the many CO sub 2 -related questions can be answered. These areas include the global carbon cycle, climate effects, and vegetation effects. Additional information is needed...

1983-01-01

436

Aluminum-carbon composite electrode  

DOEpatents

A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg.

Farahmandi, C. Joseph (Auburn, AL); Dispennette, John M. (Auburn, AL)

1998-07-07

437

Aluminum-carbon composite electrode  

DOEpatents

A high performance double layer capacitor having an electric double layer formed in the interface between activated carbon and an electrolyte is disclosed. The high performance double layer capacitor includes a pair of aluminum impregnated carbon composite electrodes having an evenly distributed and continuous path of aluminum impregnated within an activated carbon fiber preform saturated with a high performance electrolytic solution. The high performance double layer capacitor is capable of delivering at least 5 Wh/kg of useful energy at power ratings of at least 600 W/kg. 3 figs.

Farahmandi, C.J.; Dispennette, J.M.

1998-07-07

438

Elemental Carbon as Interstellar Dust  

NASA Astrophysics Data System (ADS)

C60 has not yet been detected in primitive meteorites, a finding that could demonstrate its existence in the early solar nebular or as a component of presolar dust. However, other allotropes of carbon, diamond and graphite, have been isolated from numerous chondritic samples. Studies of the isotopic composition and trace element content and these forms of carbon suggest that they condensed in circumstellar environments. Diamond may also have been produced in the early solar nebula and meteorite parent bodies by both low-temperature-low-pressure processes and shock events. Evidence for the occurrence of another carbon allotrope, with sp hybridized bonding, commonly known as carbyne, is presented.

Pillinger, C. T.

1993-04-01

439

Carbonate formation in Marslike environments  

NASA Technical Reports Server (NTRS)

A finely ground basaltic rock subjected to Marslike temperatures, atmospheric pressures and compositions and UV-rich illumination has provided a simulation system for studying carbonate growth in the Martian regolith. Growth rates of about 10 to the 12th or 13th power molecules per cu cm per sec are observed with or without the presence of liquid-phase water. The role of UV illumination in the photochemistry of water, a process which influences chemical alteration activity, is discussed. The study suggests that carbonate formation is an important aspect of Martian chemical weathering and that it provides a major chemical reservoir for outgassed carbon dioxide.

Booth, M. C.; Kieffer, H. H.

1978-01-01

440

Decrease in Carbon Isotope Rations  

NSDL National Science Digital Library

This three-panel figure is an infographic showing how carbon and oxygen isotope ratios, temperature, and carbonate sediments have changed during the Palaeocene-Eocene Thermal Maximum. The figure caption provides sources to scientific articles from which this data was derived. A graphic visualization from the Intergovernmental Panel on Climate Change shows the rapid decrease in carbon isotope ratios that is indicative of a large increase in the atmospheric greenhouse gases CO2 and CH4, which was coincident with approximately 5C of global warming.

Intergovernmental Panel on Climate Change (IPCC)

441

From PAHs to Solid Carbon  

NASA Astrophysics Data System (ADS)

Carbonaceous grains represent a major component of cosmic dust. The review will summarize new results in laboratory investigations of carbonaceous dust components. The nanometer-sized carbon particles are supposed to represent a blend of differently structured carbon including graphitic, diamond-like, fullerene-like and chain-like components on a subnanometer or nanometer scale. Recent models used to explain the structure of gas-phase condensed carbon nano-particles are discussed. Possible formation pathways of carbonaceous grains from molecular components and clusters and the role of polycyclic aromatic hydrocarbons (PAHs) and fullerenes are disclosed.

Jäger, C.; Mutschke, H.; Henning, T.; Huisken, F.

2011-03-01

442

Molecular Structure of Carbon tetrachloride  

NSDL National Science Digital Library

Carbon tetrachloride was first prepared in 1839. It was discovered by German-born French scientist Henri Victor Regnault during his work with ether/chlorine reactions. Carbon tetrachloride is a clear, heavy, poisonous, nonflammable liquid with a strong ethereal odor. It is also fairly common as a colorless gas. Carbon tetrachloride is used for dry cleaning, degreasing metals, fumigating, manufacturing refrigerants and aerosol propellants, and is also used in fire extinguishers. CCl4 is a possible carcinogen; inhalation or ingestion can cause damage to the brain, liver, kidneys, and can even cause death. CCl4 also contributes to ozone layer depletion.

2002-08-15

443

The Orbiting Carbon Observatory (OCO)  

NASA Technical Reports Server (NTRS)

CO2 is the principal human generated driver of climate change. Accurate forecasting of future climate requires an improved understanding of the global carbon cycle and its interaction with the climate system. The Orbiting Carbon Observatory (OCO) will make global, space-based observations of atmospheric CO2 with the precision, resolution, and coverage needed to understand sources and sinks. OCO data will provide critical information for decision makers including the scientific basis for policy formulation, guide for carbon management strategies and treaty monitoring.

Miller, Charles E.

2005-01-01

444

Vapor-grown carbon-fiber reinforced carbon composites  

Microsoft Academic Search

Vapor-grown carbon-fiber (VGCF) reinforced carbon (VGCF-C) composites were studied for thermal and physical properties. Effect of fiber volume fraction and final density of composite on thermal conductivity was investigated. The fiber volume fractions range from 25 v\\/o to 36% and the final densities range from 1.15 g\\/cc to 1.59 g\\/cc. A composite with a fiber volume fraction of 36% and

Jyh-Ming Ting; Max L. Lake

1995-01-01

445

Carbon Management Response Curves: Estimates of Temporal Soil Carbon Dynamics  

Microsoft Academic Search

Measurement of the change in soil carbon that accompanies a change in land use (e.g., forest to agriculture) or management (e.g., conventional tillage to no-till) can be complex and expensive, may require reference plots, and is subject to the variability of statistical sampling and short-term variability in weather. In this paper, we develop Carbon Management Response (CMR) curves that could

Tristram O. West; Gregg Marland; Anthony W. King; Wilfred M. Post; Atul K. Jain; Kenneth Andrasko

2004-01-01

446

Spin Burst Test of Carbon-Carbon Composite Disk  

Microsoft Academic Search

In order to establish design criteria for a turbine disk made of Carbon-Carbon (C\\/C) composites, spin burst tests were performed on quasi-isotropically laminated C\\/C composite disks. Un-notched and notched flat disks were prepared to evaluate the effect of stress concentration on fracture behavior.Strain measurements during rotation tests revealed that deformation of the C\\/C composite disks with or without notches was

Yasuo Kogo; Hiroshi Hatta; Hiroyuki Kawada; Takashi Shigemura; Hisaichi Ohnabe; Tomoaki Mizutani; Fumiki Tomioka

1998-01-01

447

Carbonization behaviour of some polyimide resins reinforced with carbon fibers  

Microsoft Academic Search

It was shown that the low weight loss makes the polyimide resins based on acetyl derivatives of aromatic diamines a promising candidate for carbon–carbon composites. The weight loss of this polyimide resin can reach about 30% in the composite, which is 1.5 times lower than that of the phenol-formaldehyde resin. It is suggested that the lower weight loss of the

V. E. Yudin; M. Ya. Goykhman; K. Balik; P. Glogar; G. N. Gubanova; V. V. Kudriavtsev

2000-01-01

448

Carbon--Carbon Bond Formation at Dinuclear Metal Centres  

Microsoft Academic Search

The Fischer--Tropsch synthesis of hydrocarbons probably involves an array of carbon--carbon bond-formation processes occurring to unite carbene, carbyne, alkyl, olefin, and related species on a metal surface. In seeking to understand the nature of such processes, model diruthenium complexes have been prepared and the products of their thermolysis and reactions with unsaturated hydrocarbons investigated. The combination at a diruthenium centre

R. E. Colborn; A. F. Dyke; S. A. R. Knox; Kirsty A. MacPherson; K. A. Mead; A. G. Orpen; J. Roue; P. Woodward

1982-01-01

449

THE EFFECT OF IMPURITIES ON IRON-CHROMIUM-YTTRIUM ALLOYS  

Microsoft Academic Search

A study was made of the effect of carbon, manganese, oxygen, palladium, ; and sulfur on the structure and fabricability of iron-35 wt.% chronium-1 wt.% ; yttrium alloy. Using a vacuum-induction melting technique each of the additives ; except oxygen was introduced to 1-lb remelts of a single 15-lb master alloy. The ; master alloy and remelts were made under

R. W. Endebrock; W. Chubb; E. L. Foster; R. F. Dickerson

1959-01-01

450

Direct carbonization of Al-based porous coordination polymer for synthesis of nanoporous carbon.  

PubMed

Nanoporous carbon (NPC) is prepared by direct carbonization of Al-based porous coordination polymers (Al-PCP). By applying the appropriate carbonization temperature, both high surface area and large pore volume are realized for the first time. Our NPC shows much higher porosity than other carbon materials (such as activated carbons and mesoporous carbons). This new type of carbon material exhibits superior sensing capabilities toward toxic aromatic substances. PMID:22280024

Hu, Ming; Reboul, Julien; Furukawa, Shuhei; Torad, Nagy L; Ji, Qingmin; Srinivasu, Pavuluri; Ariga, Katsuhiko; Kitagawa, Susumu; Yamauchi, Yusuke

2012-02-15

451

Carbon Finance Development Status and Development Strategy of Our Country under Low-Carbon Economy  

Microsoft Academic Search

Development of low-carbon economy has become the mainstream strategic choice of international society, and the low-carbon economy development has promoted the financial innovation enormously. The carbon finance is the financial innovation product in the low-carbon economic development process. This article, from the two aspects of low-carbon carbon investment and financing as well as the low-carbon project trades, has analyzed finance

Zhongmin Li; Luzi Zhang

2011-01-01

452

NDE for Characterizing Oxidation Damage in Reinforced Carbon-Carbon  

NASA Technical Reports Server (NTRS)

In this study, coated reinforced carbon-carbon (RCC) samples of similar structure and composition as that from the NASA space shuttle orbiter s thermal protection system were fabricated with slots in their coating simulating craze cracks. These specimens were used to study oxidation damage detection and characterization using NDE methods. These specimens were heat treated in air at 1143 and 1200 C to create cavities in the carbon substrate underneath the coating as oxygen reacted with the carbon and resulted in its consumption. The cavities varied in diameter from approximately 1 to 3 mm. Single-sided NDE methods were used since they might be practical for on-wing inspection, while x-ray micro-computed tomography (CT) was used to measure cavity sizes in order to validate oxidation models under development for carbon-carbon materials. An RCC sample having a naturally-cracked coating and subsequent oxidation damage was also studied with x-ray micro-CT. This effort is a follow-on study to one that characterized NDE methods for assessing oxidation damage in an RCC sample with drilled holes in the coating. The results of that study are briefly reviewed in this article as well. Additionally, a short discussion on the future role of simulation to aid in these studies is provided.

Roth, Don J.; Rauser, Richard W.; Jacobson, nathan S.; Wincheski, Russell A.; Walker, James L.; Cosgriff, Laura A.

2009-01-01

453

Hard elastic carbon thin films from linking of carbon nanoparticles  

NASA Astrophysics Data System (ADS)

HARD carbon thin films find many technological applications-as protective or biocompatible coatings, for instance. A very hard and elastic form of carbon nitride, in which curved graphene sheets are interlinked owing to the presence of small amounts of nitrogen, has recently been reported1. The hardness of these films is thought to arise from the presence of sp3-like bonds that introduce curvature into and bind together the sp2-bonded graphitic planes, rather as they do in hard, highly tetrahedrally bonded amorphous carbon films2-4. Here we show that hard, elastic thin films of pure carbon can be created by depositing closed, hollow graphitic carbon nanoparticles-nanotubes5 and carbon onions6-onto a substrate at high velocity. The particles are apparently disrupted on impact, causing them to link up. Electron-energy-loss spectra reveal a reduction in ? (sp2) bonding in the intersecting regions of the nanoparticles, supporting the idea that they are covalently linked by tetrahedral sp3 bonds.

Amaratunga, G. A. J.; Chhowalla, M.; Kiely, C. J.; Alexandrou, I.; Aharonov, R.; Devenish, R. M.

1996-09-01

454

Carbon isotopes in biological carbonates: Respiration and photosynthesis  

USGS Publications Warehouse

Respired carbon dioxide is an important constituent in the carbonates of most air breathing animals but is much less important in the carbonates of most aquatic animals. This difference is illustrated using carbon isotope data from freshwater and terrestrial snails, ahermatypic corals, and chemoautotrophic and methanotrophic pelecypods. Literature data from fish otoliths and bird and mammal shell and bone carbonates are also considered. Environmental CO2/O2 ratios appear to be the major controlling variable. Atmospheric CO2/O2 ratios are about thirty times lower than in most natural waters, hence air breathing animals absorb less environmental CO2 in the course of obtaining O2. Tissue CO2 therefore, does not isotopically equilibrate with environmental CO2 as thoroughly in air breathers as in aquatic animals, and this is reflected in skeletal carbonates. Animals having efficient oxygen transport systems, such as vertebrates, also accumulate more respired CO2 in their tissues. Photosynthetic corals calcify mainly during the daytime when photosynthetic CO2 uptake is several times faster than respiratory CO2 release. Photosynthesis, therefore, affects skeletal ??13C more strongly than does respiration. Corals also illustrate how "metabolic" effects on skeletal isotopic composition can be estimated, despite the presence of much larger "kinetic" isotope effects. Copyright ?? 1997 Elsevier Science Ltd.

McConnaughey, T. A.; Burdett, J.; Whelan, J. F.; Paull, C. K.

1997-01-01

455

Carbon isotopes in biological carbonates: Respiration and photosynthesis  

NASA Astrophysics Data System (ADS)

Respired carbon dioxide is an important constituent in the carbonates of most air breathing animals but is much less important in the carbonates of most aquatic animals. This difference is illustrated using carbon isotope data from freshwater and terrestrial snails, ahermatypic corals, and chemoautotrophic and methanotrophic pelecypods. Literature data from fish otoliths and bird and mammal shell and bone carbonates are also considered. Environmental CO 2/O 2 ratios appear to be the major controlling variable. Atmospheric CO 2/O 2 ratios are about thirty times lower than in most natural waters, hence air breathing animals absorb less environmental CO 2 in the course of obtaining 0 2. Tissue CO 2 therefore, does not isotopically equilibrate with environmental CO 2 as thoroughly in air breathers as in aquatic animals, and this is reflected in skeletal carbonates. Animals having efficient oxygen transport systems, such as vertebrates, also accumulate more respired CO 2 in their tissues. Photosynthetic corals calcify mainly during the daytime when photosynthetic CO 2 uptake is several times faster than respiratory CO 2 release. Photosynthesis, therefore, affects skeletal ?13C more strongly than does respiration. Corals also illustrate how "metabolic" effects on skeletal isotopic composition can be estimated, despite the presence of much larger "kinetic" isotope effects.

McConnaughey, Ted A.; Burdett, Jim; Whelan, Joseph F.; Paull, Charles K.

1997-02-01

456

Effect of coupling treatment of carbon fiber surface on mechanical properties of carbon fiber reinforced carbon composites  

Microsoft Academic Search

Unidirectional carbon fiber reinforced carbon composites (C\\/C composites) were prepared from a high modulus-type carbon fiber, treated with either silane or titanate coupling agents, and a furanic resin matrix precursor. Regardless of coupling treatments of fibers, a preferentially oriented region parallel to the fiber surface was observed at the interphase in the carbon matrix derived from furanic resin. The matrix

Norio Iwashita; Eleni Psomiadou; Yoshihiro Sawada

1998-01-01

457

Carbon nanotube filters  

NASA Astrophysics Data System (ADS)

Over the past decade of nanotube research, a variety of organized nanotube architectures have been fabricated using chemical vapour deposition. The idea of using nanotube structures in separation technology has been proposed, but building macroscopic structures that have controlled geometric shapes, density and dimensions for specific applications still remains a challenge. Here we report the fabrication of freestanding monolithic uniform macroscopic hollow cylinders having radially aligned carbon nanotube walls, with diameters and lengths up to several centimetres. These cylindrical membranes are used as filters to demonstrate their utility in two important settings: the elimination of multiple components of heavy hydrocarbons from petroleum-a crucial step in post-distillation of crude oil-with a single-step filtering process, and the filtration of bacterial contaminants such as Escherichia coli or the nanometre-sized poliovirus (~25 nm) from water. These macro filters can be cleaned for repeated filtration through ultrasonication and autoclaving. The exceptional thermal and mechanical stability of nanotubes, and the high surface area, ease and cost-effective fabrication of the nanotube membranes may allow them to compete with ceramic- and polymer-based separation membranes used commercially.

Srivastava, A.; Srivastava, O. N.; Talapatra, S.; Vajtai, R.; Ajayan, P. M.

2004-09-01

458

Carbon composites fly high  

SciTech Connect

This article describes improved techniques of resin transfer molding being used to fabricate flight-critical carbon-composite structures for aircraft and jet engines. Hand lay-up methods have been the traditional means to fabricate fiber-reinforced resin-composite parts. The procedure typically involves laying up or stacking multiple plies of preimpregnated woven fabrics in molds, then curing the sealed mold assemblies in autoclaves. The entire process is both time-consuming and labor-intensive. Only in the last few years has resin transfer molding (RTM)--a family of processes in which resin is injected into fiber preforms enclosed in heated mold cavities--emerged as a viable alternative for producing composite parts. RTM can often speed processing because it performs the shaping and curing functions in one step. The method also features the ability (in principle) to achieve precise control of the placement, orientation, and quantity of reinforcing fibers in the formed structure. Thus, RTM lends itself well to the fabrication of highly complex structural shapes that usually pose a challenge to the lay-up method.

Ashley, S.

1997-09-01

459

Hypervelocity impact resistance of reinforced carbon carbon/carbon foam thermal protection systems  

NASA Astrophysics Data System (ADS)

Common aero vehicles (CAVs) are aerodynamically designed, (from orbit) re-entry, un-powered military vehicles planned to be used for deployment of the desired munitions with increased accuracy and range. In one of the currently considered designs of the CAVs, their outer skin is planned to be constructed from two-ply panels. The outer play is made of a carbon-carbon composite while the inner ply is constructed from a carbon-based foam. In the present work a transient non-linear-dynamics-based analysis is carried out in order to predict the extent of damage and the probability for failure of the carbon-carbon/carbon-foam CAV panels during potential hypervelocity impact of space debris with the outer surface of the CAVs. The results obtained show that the extent of damage scales with the normal component of the momentum associated with the debris particles just before the impact. In addition, it is found that despite its relatively low strength, the carbon-foam can provide a major increase in the resistance of the CAV panels towards penetration of the hypervelocity debris particles. This finding has been linked with an attendant consolidation of the foam, the process that is capable of absorbing a substantial amount of kinetic energy carried by the debris particles.

Grujicic, M.; Pandurangan, B.; Zhao, C. L.; Biggers, S. B.; Morgan, D. R.

2006-05-01

460

Carbonate Production by Coral Reefs.  

National Technical Information Service (NTIS)

In the paper, the authors first create hypothetical models of coral reefs, based upon carbonate production estimates for individual organisms; then they compare the models with what is known about real reef communities and their geologic histories. The di...

K. E. Chave S. V. Smith K. J. Roy

1971-01-01

461

Graphene: A novel carbon nanomaterial  

Microsoft Academic Search

This review analyzes what the term graphene means today, and examines graphene preparation and identification methods and\\u000a its chemical properties. The applications of this novel carbon nanomaterial are briefly discussed.

S. V. Tkachev; E. Yu. Buslaeva; S. P. Gubin

2011-01-01

462

Carbon Nanotubes as Thermionic Emitters  

NASA Astrophysics Data System (ADS)

Thermionic converters are an interesting option for lightweight and long-life power generators due to a number of compelling advantages, including all solid construction, no moving parts, and waste heat rejection at high temperature. An experimental set up has been built that allows the screening of thermionic coatings and new nanomaterials from room temperature to 2000 K in high vacuum and at gap sizes as small as 1 ?m. A new class of very high temperature compatible materials, carbon nanotubes, has been investigated for their performance as cathodes. Seven different types of carbon nanotubes have been screened as thermionic emitter cathodes and compared to tungsten and nitrogen doped diamond. It has been found that some carbon nanotubes combine excellent temperature stability with good thermal emission performance. Yet, other carbon nanotubes exhibited exceptional combined thermal and field enhanced emission performance.

Loutfy, R. O.; Samandi, M.; Moravsky, A.; Strange, S.

2004-02-01

463

Carbon Fiber Risk Analysis: Conclusions  

NASA Technical Reports Server (NTRS)

It was concluded that preliminary estimates indicate that the public risk due to accidental release of carbon fiber from air transport aircraft is small. It was also concluded that further work is required to increase confidence in these estimates.

Huston, R. J.

1979-01-01

464

THERMAL REGENERATION OF ACTIVATED CARBON  

EPA Science Inventory

Ecologically, petrochemical wastes constitute a major hazard since waste materials contain relatively large amounts of non-biodegradable and toxic materials which may be discharged continuously. A three-part experimental study of activated carbon adsorption and thermal regenerati...

465

Carbon Dioxide and Ocean Acidification  

NSDL National Science Digital Library

Demonstrates the affect of increased dissolved carbon dioxide on water pH using a cheap, non-toxic acid/base indicator. Students bubble breath through a straw into red cabbage juice and note the color change.

Lewis, Chris

466

Magnesite disposal of carbon dioxide  

SciTech Connect

In this paper we report our progress on developing a method for carbon dioxide disposal whose purpose it is to maintain coal energy competitive even is environmental and political pressures will require a drastic reduction in carbon dioxide emissions. In contrast to most other methods, our approach is not aiming at a partial solution of the problem, or at buying time for phasing out fossil energy. Instead, its purpose is to obtain a complete and economic solution of the problem, and thus maintain access to the vast fossil energy reservoir. A successful development of this technology would guarantee energy availability for many centuries even if world economic growth the most optimistic estimates that have been put forward. Our approach differs from all others in that we are developing an industrial process which chemically binds the carbon dioxide in an exothermic reaction into a mineral carbonate that is thermodynamically stable and environmentally benign.

Lackner, K.S.; Butt, D.P.; Wendt, C.H.

1997-08-01

467

Non-carbon induction furnace  

DOEpatents

The present invention is directed to an induction furnace for melting and casting highly pure metals and alloys such as uranium and uranium alloys in such a manner as to minimize contamination of the melt by carbon derived from the materials and the environment within the furnace. The subject furnace is constructed of non-carbon materials and is housed within a conventional vacuum chamber. The furnace comprises a ceramic oxide crucible for holding the charge of metal or alloys. The heating of the crucible is achieved by a plasma-sprayed tungsten susceptor surrounding the crucible which, in turn, is heated by an rf induction coil separated from the susceptor by a cylinder of inorganic insulation. The furnace of the present invention is capable of being rapidly cycled from ambient temperatures to about 1650/sup 0/C for effectively melting uranium and uranium alloys without the attendant carbon contamination problems previously encountered when using carbon-bearing furnace materials.

Holcombe, C.E.; Masters, D.R.; Pfeiler, W.A.

1984-01-06

468

NASA Satellite Sees Carbon Dioxide  

NSDL National Science Digital Library

In this problem set, learners will analyze a map of atmospheric carbon dioxide derived from satellite data. Answer key is provided. This is part of Earth Math: A Brief Mathematical Guide to Earth Science and Climate Change.

469

Molecular Structure of Carbon Suboxide  

NSDL National Science Digital Library

Carbon Suboxide is a foul-smelling, lachrymatory gas produced by the dehydration of malonic acid, CH2(COOH)2, with P4O10. It is a stable molecule at -78° C, but at 25° C the compound is unstable and it polymerizes to form highly colored solid products. Under the influence of ultraviolet light (in the process known as photolysis), C3O2 decomposes to form the very reactive molecule ketene, C2O. Since carbon suboxide is the acid anhydride of malonic acid, it reacts slowly with water to produce that acid. In the laboratory, carbon suboxide, is widely used as a source of atomic carbon. As a gas it can be stored in a bulb at a pressure of a few mm Hg, but under conditions of standard temperature and pressure (300 K, 1 atm), C3O2 forms a yellow, red, or brown polymer.

2003-06-02

470

Tropical Wetlands as Carbon Sinks  

NASA Astrophysics Data System (ADS)

This presentation focuses on the tropical wetlands of sub-Saharan Africa. These are an understudied ecosystem in which large emergent grasses and sedges normally dominate and which have the potential to sequester significant amounts of carbon. Measurements of Net Primary Production of these wetlands show that they are some of the highest values recorded for any ecosystem. We have used eddy covariance to measure Net Ecosystem Exchange of pristine and disturbed wetlands and show that pristine systems can have sink strengths as strong as tropical forests while disturbed systems that have been reclaimed for agricultural purposes have a very much reduced carbon sink activity and may be net carbon sources. The management issues surrounding the use of these wetlands illustrate a direct conflict between the production of food crops for the local population and the maintenance of carbon sequestration as an ecosystem service.

Jones, M. B.; Saunders, M.

2007-12-01

471

Assimilation of Unusual Carbon Compounds  

NASA Astrophysics Data System (ADS)

Yeast taxa traditionally are distinguished by growth tests on several sugars and organic acids. During the last decades it became apparent that many yeast species assimilate a much greater variety of naturally occurring carbon compounds as sole source of carbon and energy. These abilities are indicative of a greater role of yeasts in the carbon cycle than previously assumed. Especially in acidic soils and other habitats, yeasts may play a role in the degradation of carbon compounds. Such compounds include purines like uric acid and adenine, aliphatic amines, diamines and hydroxyamines, phenolics and other benzene compounds and polysaccharides. Assimilation of purines and amines is a feature of many ascomycetes and basidiomycetes. However, benzene compounds are degraded by only a few ascomycetous yeasts (e.g. the Stephanoascus/ Blastobotrys clade and black yeastlike fungi) but by many basidiomycetes, e.g. Filobasidiales, Trichosporonales, red yeasts producing ballistoconidia and related species, but not by Tremellales. Assimilation of polysaccharides is wide-spread among basidiomycetes

Middelhoven, Wouter J.

472

Carbon storage in Amazonian podzols  

NASA Astrophysics Data System (ADS)

It has recently been discovered that Amazonian podzols may store much larger quantities of carbon than previously thought, particularly in their deep Bh horizons (over 13.6 Pg for Brazilian Amazonia alone [1]). Similarly high carbon stocks are likely to exist in similar climate/soil areas, mainly in Africa and in Borneo. Such carbon stocks raise the problem of their stability in response to changes in land use or climate. Any significant changes in vegetation cover would significantly alter the soil water dynamics, which is likely to affect organic matter turnover in soils. The direction of the change, however, is not clear and is likely to depend on the specific conditions of carbon storage and properties of the soils. It is reasonable to assume that the drying of the Bh horizons of equatorial podzols, which are generally saturated, will lead to an increase in C mineralization, although the extent of this increase has not yet been determined. These unknowns resulted in research programs, granted by the Brazilian FAPESP and the French Région PACA-ARCUS and ANR, dedicated improving estimates of the Amazonian podzol carbon stocks and to an estimate of its mineralisability. Eight test areas were determined from the analysis of remote sensing data in the larger Amazonian podzol region located in the High Rio Negro catchment and studied in detail. Despite the extreme difficulties in carrying out the field work (difficulties in reaching the study sites and extracting the soils), more than a hundred points were sampled. In all podzols the presence of a thick deep Bh was confirmed, sometimes to depths greater than 12 m. The Bh carbon was quantified, indicating that carbon stocks in these podzols are even higher than estimated recently [1]. References 1- Montes, C.R.; Lucas, Y.; Pereira, O.J.R.; Achard, R.; Grimaldi, M.; Mefli, A.J. Deep plant?derived carbon storage in Amazonian podzols. Biogeosciences, 8, 113?120, 2011.

Montes, Celia; Lucas, Yves; Pereira, Osvaldo; Merdy, Patricia; Santin, Roberta; Ishida, Débora; du Gardin, Beryl; Melfi, Adolpho

2014-05-01

473

Tunable pulsed carbon dioxide laser  

NASA Technical Reports Server (NTRS)

Transverse electrically-excited-atmosphere (TEA) laser is continuously tunable over several hundred megahertz about centers of spectral lines of carbon dioxide. It is operated in single longitudinal mode (SLM) by injection of beam from continuous-wave, tunable-waveguide carbon dioxide laser, which serves as master frequency-control oscillator. Device measures absorption line of ozone; with adjustments, it is applicable to monitoring of atmospheric trace species.

Megie, G. J.; Menzies, R. T.

1981-01-01

474

Selective functionalization of carbon nanotubes  

NASA Technical Reports Server (NTRS)

The present invention is directed toward methods of selectively functionalizing carbon nanotubes of a specific type or range of types, based on their electronic properties, using diazonium chemistry. The present invention is also directed toward methods of separating carbon nanotubes into populations of specific types or range(s) of types via selective functionalization and electrophoresis, and also to the novel compositions generated by such separations.

Strano, Michael S. (Inventor); Usrey, Monica (Inventor); Barone, Paul (Inventor); Dyke, Christopher A. (Inventor); Tour, James M. (Inventor); Kittrell, W. Carter (Inventor); Hauge, Robert H. (Inventor); Smalley, Richard E. (Inventor)

2009-01-01

475

Hydrogen electrode in molten carbonate  

Microsoft Academic Search

Open-circuit potentials are reported for the hydrogen (Au) electrode in molten carbonate at 650°C. The data, with few exceptions, agree with thermodynamic values calculated assuming simultaneous equilibrium of the shift and the methane reactions. The exceptions are those instances where methane has to be oxidized almost completely to reach equilibrium, and those where carbon can form during preheating of the

W. M. Vogel; C. D. Iacovangelo

1977-01-01

476

Activated carbons from sewage sludge  

Microsoft Academic Search

Activated carbons of different characteristics have been prepared from dried sewage sludge using CO2, air and KOH as activating agents. The adsorption capacity of the resulting materials has been checked using 4-chlorophenol as a target compound in aqueous solution. CO2 and air-activation led to carbons of low BET area which increased with the activation temperature but did not reach 100m2\\/g

Victor Manuel Monsalvo; Angel Fernandez Mohedano; Juan Jose Rodriguez

2011-01-01

477

CARBONIZER TESTS WITH LAKELAND FEEDSTOCKS  

SciTech Connect

Research has been conducted under United States Department of Energy Contract (USDOE) DE-AC21-86MC21023 to develop a new type of coal-fired plant for electric power generation. This new type of plant, called a Second Generation Pressurized Fluidized Bed Combustion Plant (2nd Gen PFB), offers the promise of efficiencies greater than 48%, with both emissions and a cost of electricity that are significantly lower than those of conventional pulverized coal-fired (PC) plants with wet flue gas desulfurization/scrubbers. The 2nd Gen PFB plant incorporates the partial gasification of coal in a carbonizer, the combustion of carbonizer char in a pressurized circulating fluidized (PCFB) bed boiler, and the combustion of carbonizer syngas in a topping combustor to achieve gas turbine inlet temperatures of 2700 F and higher. Under the USDOE Clean Coal V Demonstration Plant Program, a nominal 260 MWe plant demonstrating 2nd Gen PFB technology has been proposed for construction at the McIntosh Power Plant of the City of Lakeland, Florida. In the September-December 1997 time period, four test runs were conducted in Foster Wheeler's 12-inch diameter carbonizer pilot plant in Livingston New Jersey to ascertain carbonizer performance characteristics with the Kentucky No. 9 coal and Florida limestone proposed for use in the Lakeland plant. The tests were of a short-term nature exploring carbonizer carbon conversions, sulfur capture efficiencies and syngas alkali levels. The tests were successful; observed carbonizer performance was in agreement with predictions and no operating problems, attributed to the planned feedstocks, were encountered. The results of the four test runs are reported herein.

C. Lu; Z. Fan; R. Froehlich; A. Robertson

2003-09-01

478

Carbon Nanotube Electronics and Optoelectronics  

Microsoft Academic Search

Carbon nanotube field-effect transistors (CNFETs) are already competitive in some respects with state-of-the-art silicon transistors,\\u000a and are promising candidates for future nanoelectronic devices. However, it is dificult to form ohmic contacts to carbon nanotubes,\\u000a and most of the CNFETs reported to date operate as Schottky barrier transistors rather than conventional FETs. The electrostatics\\u000a at the contact of a metal to

Stefan Heinze; Jerry Tersoff; Phaedon Avouris

2005-01-01

479

Carbon Dioxide - Sources and Sinks  

NSDL National Science Digital Library

In this lab activity, students use a chemical indicator (bromothymol blue) to detect the presence of carbon dioxide in animal and plant respiration and in the burning of fossil fuels and its absence in the products of plant photosynthesis. After completing the five parts of this activity, students compare the colors of the chemical indicator in each part and interpret the results in terms of the qualitative importance of carbon sinks and sources.

Universe, Windows T.

480

High-pressure wet carbonization  

SciTech Connect

The objectives of this program are to design and construct a continuous wet carbonization process development unit (PDU), and to operate the PDU to determine the effects of temperature and residence time on the dewaterability and heat value of Minnesota, North Carolina, and Maine peats. Additional information will be generated on the effect that the wet carbonization process has on the hydrogasification characteristics of these peats. Further information on the heat transfer and slurry transport characteristics will also be obtained.

Paganessi, J.E.; Knowlton, T.M.; Punwani, D.V.; Lau, F.S.

1981-04-01

481

Combustion processes for carbon capture  

Microsoft Academic Search

A review of the technologies for coal-based power generation closest to commercial application involving carbon capture is presented. Carbon capture and storage (CCS) developments are primarily adaptations of conventional combustion systems, with additional unit operations such as bulk oxygen supply, CO2 capture by sorbents, CO2 compression, and storage. They use pulverized coal combustion in entrained flow—the dominant current technology for

Terry F. Wall

2007-01-01

482

PECVD Growth of Carbon Nanotubes  

NASA Technical Reports Server (NTRS)

Plasma enhanced chemical vapor deposition (PECVD), using inductively coupled plasma, has been used to grow carbon nanotubes (CNTs) and graphitic carbon fibers (GCF) on substrates sputtered with aluminum and iron catalyst. The capacitive plasma's power has been shown to cause a transition from nanotubes to nanofibers, depending on the strength of the plasma. The temperature, placement, and other factors have been shown to affect the height and density of the tube and fiber growth.

McAninch, Ian; Arnold, James O. (Technical Monitor)

2001-01-01

483

Stable Carbon and Nitrogen Isotopic  

Microsoft Academic Search

The perennially ice-covered lakes in the McMurdo Dry Valleys, Antarctica, are part of the coldest and driest ecosystem on earth. To understand lacustrine carbon and nitrogen cycling in this end-member ecosystem, and to define paleolimnological proxies for ice-covered lakes, we measured the stable carbon and nitrogen isotopic composition of particulate organic matter (POM) and benthic organic matter (BOM) within the

Jennifer Lawson; PETER T. DORAN; Fabien Kenig; DAVID J. DES MARAIS; JOHN C. PRISCU

2004-01-01

484

Lithographically defined microporous carbon structures  

DOEpatents

A lithographic method is used to fabricate porous carbon structures that can provide electrochemical electrodes having high surface area with uniform and controllable dimensions, providing enormous flexibility to tailor the electrodes toward specific applications. Metal nanoparticles deposited on the surface of the porous carbon electrodes exhibit ultra small dimensions with uniform size distribution. The resulting electrodes are rugged, electrically conductive and show excellent electrochemical behavior.

Burckel, David Bruce; Washburn, Cody M.; Polsky, Ronen; Brozik, Susan M.; Wheeler, David R.

2013-01-08

485

Nickel and the Carbon Cycle†  

PubMed Central

This article, dedicated to Edward Stiefel, reviews three nickel enzymes that play important roles in the carbon cycle: CO dehydrogenase, acetyl-CoA synthase, and methyl-coenzyme M reductase. After a short discussion of the carbon cycle, the structures of the active centers of the proteins and their proposed mechanisms are discussed. A brief description of future research areas is presented for each enzyme system. A short perspective on future research on nickel enzymes ends this contribution.

Ragsdale, Stephen W.

2007-01-01

486

Overview of Nanotechnology: Carbon Nanotubes  

NSDL National Science Digital Library

This overview of nanotechnology is presented by the NaMCATE project. Carbon nanotubes are "cylindrical molecules with a diameter as small as 1 nm and a length up to several millimeters. Consisting only of carbon atoms, they are cylinders made of a single layer of graphene." This lesson provides both an overview of nanotubes and a powerpoint presentation.Users must create a free login in order to access materials.

2011-09-21

487

The Carbon Budget of California  

NASA Astrophysics Data System (ADS)

The carbon budget of a region can be defined as the sum of annual fluxes of carbon dioxide and methane greenhouse gases (GHGs) into and out of the regional surface coverage area. According to the state government’s recent inventory, California's carbon budget is presently dominated by fossil fuel emissions of CO2 (at >85% of total annual GHG emissions) to meet energy and transportation requirements. Other notable (non-ecosystem) sources of carbon GHG emissions in 2004 were from cement- and lime-making industries, livestock-based agriculture, and waste treatment activities. The NASA-CASA (Carnegie Ames Stanford Approach) simulation model based on satellite observations of monthly vegetation cover (including those from the Moderate Resolution Imaging Spectroradiometer - MODIS) has been used to estimate net ecosystem fluxes and vegetation biomass production over the period 1990-2004. California's annual NPP for all ecosystems in the early 2000s, estimated by CASA at 120 million metric tons of carbon equivalent (MMTCE) per year, was roughly equal to its annual fossil fuel emission rates for carbon. However, since natural ecosystems can accumulate only a small fraction of this annual NPP total in long-term storage pools, the net ecosystem sink flux for atmospheric carbon across the state was estimated at a maximum rate of between 15-24 MMTCE per year under favorable precipitation conditions. Under less favorable precipitation conditions, such as those experienced during the early 1990s, ecosystems statewide were estimated to have lost nearly 15 MMTCE per year to the atmosphere. Considering the large amounts of carbon stored in standing biomass of forests, shrublands, and rangelands across the state, the implications of changing climate and land use practices on ecosystems must be factored into the state’s planning to reduce overall GHG emissions.

Potter, C. S.

2009-12-01

488

Polysaccharide-carbon nanotube complex  

US Patent & Trademark Office Database

Disclosed is a complex which comprises a carbon nanotube and a modified polysaccharide having a backbone chain with the side thereof being introduced with monosaccharide or oligosaccharide residues. The polysaccharide is preferably .beta.-1,3-glucan. The complex is prepared by admixing a solution of the modified polysaccharide dissolved in an aprotic polar solvent or a strong alkali solution with an aqueous dispersion of the carbon nanotube, and incubating the mixture.

2011-05-03

489

Impurity effects in carbon fibres  

Microsoft Academic Search

Outgassing experiments have been performed on a variety of polyacrylonitrile- and rayon-based carbon yarns. Major residual impurities, as well as those introduced from surface treatments, have been identified. Sulphur has been shown to be a major impurity of rayon-based carbon fibres, with concentrations up to 3110 ppm by weight having been determined by neutron-activation analyses. Removal of this contaminant as

M. L. Lieberman; G. T. Noles

1972-01-01

490

Humidity behavior of thermally carbonized porous silicon  

Microsoft Academic Search

We have studied the humidity behavior of thermally carbonized (TC) p+-type porous silicon (PS) samples as a function of carbonization temperature. The Fourier transform infrared (FTIR) spectroscopy and gas adsorption measurements indicate that the bond configuration and structure of thermally carbonized porous silicon surface are highly dependent on carbonization temperature. Moreover, the surface affects on the stability of porous silicon

Mikko Björkqvist; Jarno Salonen; Ensio Laine

2004-01-01