WorldWideScience

Sample records for carbon diooxide mixing

  1. Mixed-layer carbon cycling at the Kuroshio Extension Observatory

    Science.gov (United States)

    Fassbender, Andrea J.; Sabine, Christopher L.; Cronin, Meghan F.; Sutton, Adrienne J.

    2017-02-01

    Seven years of data from the NOAA Kuroshio Extension Observatory (KEO) surface mooring, located in the North Pacific Ocean carbon sink region, were used to evaluate drivers of mixed-layer carbon cycling. A time-dependent mass balance approach relying on two carbon tracers was used to diagnostically evaluate how surface ocean processes influence mixed-layer carbon concentrations over the annual cycle. Results indicate that the annual physical carbon input is predominantly balanced by biological carbon uptake during the intense spring bloom. Net annual gas exchange that adds carbon to the mixed layer and the opposing influence of net precipitation that dilutes carbon concentrations make up smaller contributions to the annual mixed-layer carbon budget. Decomposing the biological term into annual net community production (aNCP) and calcium carbonate production (aCaCO3) yields 7 ± 3 mol C m-2 yr-1 aNCP and 0.5 ± 0.3 mol C m-2 yr-1 aCaCO3, giving an annually integrated particulate inorganic carbon to particulate organic carbon production ratio of 0.07 ± 0.05, as a lower limit. Although we find that vertical physical processes dominate carbon input to the mixed layer at KEO, it remains unclear how horizontal features, such as eddies, influence carbon production and export by altering nutrient supply as well as the depth of winter ventilation. Further research evaluating linkages between Kuroshio Extension jet instabilities, eddy activity, and nutrient supply mechanisms is needed to adequately characterize the drivers and sensitivities of carbon cycling near KEO.

  2. Benefits of tree mixes in carbon plantings

    Science.gov (United States)

    Hulvey, Kristin B.; Hobbs, Richard J.; Standish, Rachel J.; Lindenmayer, David B.; Lach, Lori; Perring, Michael P.

    2013-10-01

    Increasingly governments and the private sector are using planted forests to offset carbon emissions. Few studies, however, examine how tree diversity -- defined here as species richness and/or stand composition -- affects carbon storage in these plantings. Using aboveground tree biomass as a proxy for carbon storage, we used meta-analysis to compare carbon storage in tree mixtures with monoculture plantings. Tree mixes stored at least as much carbon as monocultures consisting of the mixture's most productive species and at times outperformed monoculture plantings. In mixed-species stands, individual species, and in particular nitrogen-fixing trees, increased stand biomass. Further motivations for incorporating tree richness into planted forests include the contribution of diversity to total forest carbon-pool development, carbon-pool stability and the provision of extra ecosystem services. Our findings suggest a two-pronged strategy for designing carbon plantings including: (1) increased tree species richness; and (2) the addition of species that contribute to carbon storage and other target functions.

  3. Effect of carbon on ion beam mixing of Fe-Ti bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Hirvonen, J.P.; Nastasi, M.; Lappalainen, R.; Sickafus, K. (Los Alamos National Lab., NM (USA); Helsinki Univ. (Finland). Dept. of Physics; Los Alamos National Lab., NM (USA))

    1989-01-01

    The influence of implanted carbon on ion beam mixing of a Fe-Ti system was investigated. Carbon was introduced into bilayer samples by implanting {sup 13}C isotopes. The implantation energies were selected to set the mean range of carbon ions in either the iron or titanium layer. The effect of implanted carbon on 400 keV Ar ion mixing in the temperature range from 0 to 300{degree}C was studied using Rutherford backscattering spectroscopy at the energy of 5 MeV. Changes in carbon concentration profiles were probed utilizing the resonance of the nuclear reaction {sup 13}C(p,{gamma}){sup 14}N at the proton energy of 1.748 MeV. The measurements revealed that mixing was not affected by carbon implanted into the titanium layer. However, carbon in the iron layer remarkably retarded mixing at all temperatures investigated. Significant changes in carbon depth distributions were observed only when the sample with implanted carbon in the iron layer was mixed at 300{degree}C. These results are explained in terms of the enhanced mobility of carbon in an evaporated iron film which allows segregation to the interface. At low temperatures, however, vacancy-carbon interaction in iron may have a contribution to the retarded ion beam mixing. 19 refs., 3 figs.

  4. Mixed Carbon Policies Based on Cooperation of Carbon Emission Reduction in Supply Chain

    Directory of Open Access Journals (Sweden)

    Yongwei Cheng

    2017-01-01

    Full Text Available This paper established cooperation decision model for a mixed carbon policy of carbon trading-carbon tax (environmental tax in a two-stage S-M supply chain. For three different cooperative abatement situations, we considered the supplier driven model, the manufacturer driven model, and the equilibrium game model. We investigated the influence of mixed carbon policy with constraint of reduction targets on supply chain price, productivity, profits, carbon emissions reduction rate, and so on. The results showed that (1 high-strength carbon policies do not necessarily encourage enterprises to effectively reduce emissions, and increasing market acceptance of low carbon products or raising the price of carbon quota can promote the benign reduction; (2 perfect competitive carbon market has a higher carbon reduction efficiency than oligarch carbon market, but their optimal level of cooperation is the same and the realized reduction rate is in line with the intensity of carbon policy; (3 the policy sensitivity of the carbon trading mechanism is stronger than the carbon tax; “paid quota mechanism” can subsidize the cost of abatement and improve reduction initiative. Finally, we use a numerical example to solve the optimal decisions under different market situations, validating the effectiveness of model and the conclusions.

  5. Mixed resin and carbon fibres surface treatment for preparation of carbon fibres composites with good interfacial bonding strength

    International Nuclear Information System (INIS)

    He, Hongwei; Wang, Jianlong; Li, Kaixi; Wang, Jian; Gu, Jianyu

    2010-01-01

    The objective of this work is to improve the interlaminar shear strength of composites by mixing epoxy resin and modifying carbon fibres. The effect of mixed resin matrix's structure on carbon fibres composites was studied. Anodic oxidation treatment was used to modify the surface of carbon fibres. The tensile strength of multifilament and interlaminar shear strength of composites were investigated respectively. The morphologies of untreated and treated carbon fibres were characterized by scanning electron microscope and X-ray photoelectron spectroscopy. Surface analysis indicates that the amount of carbon fibres chemisorbed oxygen-containing groups, active carbon atom, the surface roughness, and wetting ability increases after treatment. The tensile strength of carbon fibres decreased little after treatment by anodic oxidation. The results show that the treated carbon fibres composites could possess excellent interfacial properties with mixed resins, and interlaminar shear strength of the composites is up to 85.41 MPa. The mechanism of mixed resins and treated carbon fibres to improve the interfacial property of composites is obtained.

  6. Mixed structures in continuously cooled low-carbon automotive steels

    International Nuclear Information System (INIS)

    Khalid, F.A.; Edmonds, D.V.

    1993-01-01

    Mixed microstructures have been studied in low- carbon microalloyed steels suitable for automotive applications, after continuous cooling from the hot-rolled condition. Microstructural features such as polygonal ferrite, bainitic and acicular ferrite and microphase constituent are identified using transmission electron microscopy. The influence of these mixed structures on the tensile strength, impact toughness and fracture behaviour is examined. It is found that improvements in impact toughness as compared with microalloyed medium- carbon ferrite/pearlite steels can be achieved from these predominantly acicular structures developed by controlling alloy composition and continuous cooling of these lower carbon steels. (orig.)

  7. Investigation of bioresistant dry building mixes modified by carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Korolev Evgeniy Valer'evich

    2015-04-01

    Full Text Available Dry construction mixes are today a product of high technologies. Depending on the purpose and requirements to the properties it is easy to produce dry construction mixes with different compositions and operating indicators in plant conditions using the necessary modifying additives. Cement, gypsum and other mineral binders are used in the construction mixes. Different types of cement are more heavily used in dry construction mixes. Such dry mixes are believed to be more effective materials comparing to traditional cement-sandy solutions of centralized preparation. The authors present the results of the investigations on obtaining biocidal cement-sand compositions. It was established, that introduction of sodium sulfate into the composition provides obtaining the materials with funginert and fungicide properties. The strength properties of the mixes modified by carbon nanotubes and biocide additive were investigated by mathematical planning methods. The results of the investigations showed that the modification of cement stone structure by carbon nanotubes positively influences their strength and technological properties. Nanomodifying of construction composites by introducing carbon nanotubes may be effectively used at different stages of structure formation of a construction material.

  8. Carbon-enhanced metal-poor stars and thermohaline mixing

    NARCIS (Netherlands)

    Stancliffe, R.J.; Glebbeek, E.; Izzard, R.G.; Pols, O.R.

    2007-01-01

    One possible scenario for the formation of carbon-enhanced metal-poor stars is the accretion of carbon-rich material from a binary companion which may no longer visible. It is generally assumed that the accreted material remains on the surface of the star and does not mix with the interior until

  9. Carbon bed mercury emissions control for mixed waste treatment.

    Science.gov (United States)

    Soelberg, Nick; Enneking, Joe

    2010-11-01

    Mercury has various uses in nuclear fuel reprocessing and other nuclear processes, and so it is often present in radioactive and mixed (radioactive and hazardous) wastes. Compliance with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards can require off-gas mercury removal efficiencies up to 99.999% for thermally treating some mixed waste streams. Test programs have demonstrated this level of off-gas mercury control using fixed beds of granular sulfur-impregnated activated carbon. Other results of these tests include (1) the depth of the mercury control mass transfer zone was less than 15-30 cm for the operating conditions of these tests; (2) MERSORB carbon can sorb mercury up to 19 wt % of the carbon mass; and (3) the spent carbon retained almost all (98.3-99.99%) of the mercury during Toxicity Characteristic Leachability Procedure (TCLP) tests, but when even a small fraction of the total mercury dissolves, the spent carbon can fail the TCLP test when the spent carbon contains high mercury concentrations.

  10. Mixing ratios of carbon monoxide in the troposphere

    Energy Technology Data Exchange (ETDEWEB)

    Novelli, P.C.; Steele, L.P. (Univ. of Colorado, Boulder (United States)); Tans, P.P. (NOAA, Boulder, CO (United States))

    1992-12-20

    Carbon monoxide (CO) mixing ratios were measured in air samples collected weekly at eight locations. The air was collected as part of the CMDL/NOAA cooperative flask sampling program (Climate Monitoring and Diagnostics Laboratory, formerly Geophysical Monitoring for Climatic Change, Air Resources Laboratory/National Oceanic and Atmospheric Administration) at Point Barrow, Alaska, Niwot Ridge, Colorado, Mauna Loa and Cape Kumakahi, Hawaii, Guam, Marianas Islands, Christmas Island, Ascension Island and American Samoa. Half-liter or 3-L glass flasks fitted with glass piston stopcocks holding teflon O rings were used for sample collection. CO levels were determined within several weeks of collection using gas chromatography followed by mercuric oxide reduction detection, and mixing ratios were referenced against the CMDL/NOAA carbon monoxide standard scale. During the period of study (mid-1988 through December 1990) CO levels were greatest in the high latitudes of the northern hemisphere (mean mixing ratio from January 1989 to December 1990 at Point Barrow was approximately 154 ppb) and decreased towards the south (mean mixing ratio at Samoa over a similar period was 65 ppb). Mixing ratios varied seasonally, the amplitude of the seasonal cycle was greatest in the north and decreased to the south. Carbon monoxide levels were affected by both local and regional scale processes. The difference in CO levels between northern and southern latitudes also varied seasonally. The greatest difference in CO mixing ratios between Barrow and Samoa was observed during the northern winter (about 150 ppb). The smallest difference, 40 ppb, occurred during the austral winter. The annually averaged CO difference between 71[degrees]N and 14[degrees]S was approximately 90 ppb in both 1989 and 1990; the annually averaged interhemispheric gradient from 71[degrees]N to 41[degrees]S is estimated as approximately 95 ppb. 66 refs., 5 figs., 5 tabs.

  11. Lightweight Brick by Carbon Ash from The Mixed Plastic Waste Treatment Plant

    OpenAIRE

    Chen Kuo-Wei

    2016-01-01

    This study was designed to investigate the mixed plastic waste from the production of light carbon ash bricks performance. The mixed waste plastic pyrolysis process generated waste - Carbon ash. After extrusion, a Lightweight brick was made by carbon ash, additive and Cement mortar. In general, the set compressive strength and insulation effect of lightweight bricks with carbon ash proportion for significant impact. The set water absorption and thermal conductivity of lightweight bricks with ...

  12. Plutonium oxides and uranium and plutonium mixed oxides. Carbon determination

    International Nuclear Information System (INIS)

    Anon.

    Determination of carbon in plutonium oxides and uranium plutonium mixed oxides, suitable for a carbon content between 20 to 3000 ppm. The sample is roasted in oxygen at 1200 0 C, the carbon dioxide produced by combustion is neutralized by barium hydroxide generated automatically by coulometry [fr

  13. Mixed Solvent Reactive Recrystallization of Sodium Carbonate

    NARCIS (Netherlands)

    Gaertner, R.S.

    2005-01-01

    Investigation of the reactive recrystallization of trona (sodium sesquicarbonate) and sodium bicarbonate to sodium carbonate (soda) in a mixed solvent led to the design of several alternative, less energy consumptive, economically very attractive process routes for the production of soda from all

  14. Analysis of refabricated fuel: determination of carbon in uranium plutonium mixed carbide

    International Nuclear Information System (INIS)

    Huwyler, S.

    1977-09-01

    In developing uranium plutonium mixed carbide which represents an advanced fuel for breeder reactors carbon analysis is an important means of determining the stoichiometry. Methods of carbon determination are briefly reviewed. The carbon determination using a LECO WR-12 Carbon Determinator is treated in detail and experience of three years operation communicated. Problems arising from operating the LECO-apparatus in a glove box are discussed. It is pointed out that carbon determination with the LECO-apparatus is a very fast method with good precision and well suited for the routine analysis of mixed carbide fuel. The accuracy of the method is checked by means of a standard. (Auth.)

  15. Carbon emission allowance allocation with a mixed mechanism in air passenger transport.

    Science.gov (United States)

    Qiu, Rui; Xu, Jiuping; Zeng, Ziqiang

    2017-09-15

    Air passenger transport carbon emissions have become a great challenge for both governments and airlines because of rapid developments in the aviation industry in recent decades. In this paper, a mixed mechanism composed of a cap-and-trade mechanism and a carbon tax mechanism is developed to assist governments in allocating carbon emission allowances to airlines operating on the routes. Combined this mixed mechanism with an equilibrium strategy, a bi-level multi-objective model is proposed for an air passenger transport carbon emission allowance allocation problem, in which a government is considered as a leader and the airlines as the followers. An interactive solution approach integrating a genetic algorithm and an interactive evolutionary mechanism is designed to search for satisfactory solutions of the proposed model. A case study is then presented to show its practicality and efficiency in mitigating carbon emissions. Sensitivity analyses under different tradable and taxable levels are also conducted, which can give the government insights as to the tradeoffs between lowering carbon intensity and improving airlines' operations. The computational results demonstrate that the mixed mechanism can assist greatly in carbon emission mitigation for air passenger transport and therefore, it should be established as part of air passenger transport carbon emission policies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Carbon Bed Mercury Emissions Control For Mixed Waste Treatment

    International Nuclear Information System (INIS)

    Soelberg, Nick; Enneking, Joe

    2010-01-01

    Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (both radioactive and hazardous according to the Resource Conservation and Recovery Act) wastes. Depending on regulatory requirements, the mercury in the off-gas must be controlled with sometimes very high efficiencies. Compliance to the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards can require off-gas mercury removal efficiencies up to 99.999% for thermally treating some mixed waste streams. Several test programs have demonstrated this level of off-gas mercury control using fixed beds of granular sulfur-impregnated activated carbon. Other results of these tests include: (a) The depth of the mercury control mass transfer zone was less than 15-30 cm for the operating conditions of these tests, (b) MERSORB(reg s ign) carbon can sorb Hg up to 19 wt% of the carbon mass, and (c) the spent carbon retained almost all (98-99.99%) of the Hg; but when even a small fraction of the total Hg dissolves, the spent carbon can fail the TCLP test when the spent carbon contains high Hg concentrations. Localized areas in a carbon bed that become heated through heat of adsorption, to temperatures where oxidation occurs, are referred to as 'bed hot spots.' Carbon bed hot spots must be avoided in processes that treat radioactive and mixed waste. Key to carbon bed hot spot mitigation are (a) designing for sufficient gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) monitoring and control of inlet gas flowrate, temperature, and composition, (c) monitoring and control of in-bed and bed outlet gas temperatures, and (d) most important, monitoring of bed outlet CO concentrations. An increase of CO levels in the off-gas downstream of the carbon bed to levels about 50-100 ppm higher than the inlet CO concentration indicate CO formation in the bed, caused by carbon bed

  17. A study of the mixing state of black carbon in urban zone

    Science.gov (United States)

    Mallet, M.; Roger, J. C.; Despiau, S.; Putaud, J. P.; Dubovik, O.

    2004-02-01

    The knowledge of the mixing state of black carbon particle with other aerosol species is critical for adequate simulations of the direct radiative effect of black carbon particles and its effect on climate. This paper reports the investigation of the mixing state of black carbon aerosol in the urban zone. The study uses a combination of in situ and ground-based remote sensing observations conducted during the ESCOMPTE experiment, which took place in industrialized region in France in summer of 2001. The criteria we used for identifying mixing state relies on the known enhancement of absorption for aerosol composed by internal versus external mixtures of black carbon with weakly absorbing aerosol components. First, using in situ aerosol data, we performed Mie computations and reconstructed the single scattering albedo of aerosol for the two different mixing assumptions: black carbon mixed externally or internally with other aerosol species. Then, we compared the obtained values ωo,int and ωo,ext with the retrievals of ωo from independent AERONET Sun-photometric measurements. The aerosol single scattering albedo (ωo,aer.) derived from the AERONET photometer observations (with the mean value equal to 0.84 ± 0.04) was found to be close to ωo,ext reconstructed from in situ observation under assumptions of external mixture. This similarity between AERONET values and external mixture simulations was observed during all the days studied. Our conclusion on external mixture of black carbon aerosol with other particles in urban zone during ESCOMPTE (close to the pollution source) is coherent with observations made during other independent studies reported in a number of recent publications.

  18. Evaluating The Performance of Asphalt Concrete Mixes by Utilizing Carbon Black as Asphalt Modifier

    Directory of Open Access Journals (Sweden)

    Aliaa Faleh Al.ani

    2018-02-01

    Full Text Available Carbon black produced from several factories in Iraq is expected to provide a reinforcing agent for asphalt paving materials. Carbon black has many characteristics that distinguish  it from conventional mineral fillers, as well as their different function in pavement mixtures. Theory and exercise advanced  in the inclusive utilize of carbon black as a reinforcing agent for rubber has led to concept of asphalt reinforcement. The very fine particles of micro filler added in different contents will be dispersed in asphalt cement improving the mechanical properties of asphalt concrete mixes. In this Four percentages rates were utilized; 0, 3, 6, and 9 percent adding to asphalt grade (60-70. Mixes of asphalt concrete were destined at their optimum asphalt content (OAC then experienced to assess their engineering characteristics that contain moisture of damage, permanent deformation, modulus of resilient and characteristics of fatigue. These characteristics have been assessed utilizing indirect tensile strength, uniaxial repeated loading and repeated flexural beam tests. Mixtures improved with carbon black were existed to have amended permanent deformation and fatigue characteristics, else exhibited high resilient modulus and lower moisture susceptibility. Result showed that a rate changed from 3 to 9 percent has shown an increase in resilient modulus for increment of carbon black and modulus of resilient for mixes with 9 percent carbon black was 1.4 times that for mixes with 0 percent carbon black. The altering of carbon black from a range (3-9 percent has modified the fatigue property of the asphalt concrete mixes as determined by flexural test, Significantly, to modify the asphalt concrete manner taken the  percent of carbon black 6, and to produce the mixes more durable , higher resistance to distresses by adding the local knowledge.

  19. Optics of Water Cloud Droplets Mixed with Black-Carbon Aerosols

    Science.gov (United States)

    Mishchenko, Michael I.; Liu, Li; Cairns, Brian; Mackowski, Daniel W.

    2014-01-01

    We use the recently extended superposition T-matrix method to calculate scattering and absorption properties of micrometer-sized water droplets contaminated by black carbon. Our numerically exact results reveal that, depending on the mode of soot-water mixing, the soot specific absorption can vary by a factor exceeding 6.5. The specific absorption is maximized when the soot material is quasi-uniformly distributed throughout the droplet interior in the form of numerous small monomers. The range of mixing scenarios captured by our computations implies a wide range of remote sensing and radiation budget implications of the presence of black carbon in liquid-water clouds. We show that the popular Maxwell-Garnett effective-medium approximation can be used to calculate the optical cross sections, single-scattering albedo, and asymmetry parameter for the quasi-uniform mixing scenario, but is likely to fail in application to other mixing scenarios and in computations of the elements of the scattering matrix.

  20. Lightweight Brick by Carbon Ash from The Mixed Plastic Waste Treatment Plant

    Directory of Open Access Journals (Sweden)

    Chen Kuo-Wei

    2016-01-01

    Full Text Available This study was designed to investigate the mixed plastic waste from the production of light carbon ash bricks performance. The mixed waste plastic pyrolysis process generated waste - Carbon ash. After extrusion, a Lightweight brick was made by carbon ash, additive and Cement mortar. In general, the set compressive strength and insulation effect of lightweight bricks with carbon ash proportion for significant impact. The set water absorption and thermal conductivity of lightweight bricks with carbon ash proportion for significant impact. The set density of lightweight brick ameliorates with M3824 additive and CM3 cement mortar for significant impact. Under conditions of technology and economic, the results of this study as reference for market-oriented marketing and commercialization of production.

  1. Sustainability Concept in Decision-Making: Carbon Tax Consideration for Joint Product Mix Decision

    OpenAIRE

    Wen-Hsien Tsai; Jui-Chu Chang; Chu-Lun Hsieh; Tsen-Shu Tsaur; Chung-Wei Wang

    2016-01-01

    Carbon emissions are receiving greater scrutiny in many countries due to international forces to reduce anthropogenic global climate change. Carbon taxation is one of the most common carbon emission regulation policies, and companies must incorporate it into their production and pricing decisions. Activity-based costing (ABC) and the theory of constraints (TOC) have been applied to solve product mix problems; however, a challenging aspect of the product mix problem involves evaluating joint m...

  2. Carbon Trading in the Policy mix

    International Nuclear Information System (INIS)

    Sijm, J.P.M.; Sorrell, S.

    2003-12-01

    The Kyoto Protocol is stimulating the development of emissions-trading schemes at the national and international levels. These are being introduced alongside existing policy instruments such as carbon taxes and negotiated agreements, leading to complex problems of policy interaction. But the topic of policy interaction remains under-researched. This paper aims to improve understanding of such interactions by examining the conditions under which a cap-and-trade scheme for carbon-dioxide emissions may usefully coexist with carbon/energy taxes, support mechanisms for renewable electricity, and policies to promote energy efficiency. The paper argues that each of these instrument combinations may be acceptable, provided they contribute to either improving the static or dynamic efficiency of the trading scheme, or delivering other valued policy objectives. But, since the coexisting instruments may raise overall abatement costs while contributing nothing further to emission reductions, the objectives and trade-offs within the policy mix must be explicit

  3. Sustainability Concept in Decision-Making: Carbon Tax Consideration for Joint Product Mix Decision

    Directory of Open Access Journals (Sweden)

    Wen-Hsien Tsai

    2016-11-01

    Full Text Available Carbon emissions are receiving greater scrutiny in many countries due to international forces to reduce anthropogenic global climate change. Carbon taxation is one of the most common carbon emission regulation policies, and companies must incorporate it into their production and pricing decisions. Activity-based costing (ABC and the theory of constraints (TOC have been applied to solve product mix problems; however, a challenging aspect of the product mix problem involves evaluating joint manufactured products, while reducing carbon emissions and environmental pollution to fulfill social responsibility. The aim of this paper is to apply ABC and TOC to analyze green product mix decision-making for joint products using a mathematical programming model and the joint production data of pharmaceutical industry companies for the processing of active pharmaceutical ingredients (APIs in drugs for medical use. This paper illustrates that the time-driven ABC model leads to optimal joint product mix decisions and performs sensitivity analysis to study how the optimal solution will change with the carbon tax. Our findings provide insight into ‘sustainability decisions’ and are beneficial in terms of environmental management in a competitive pharmaceutical industry.

  4. Calcium carbonate-calcium phosphate mixed cement compositions for bone reconstruction.

    Science.gov (United States)

    Combes, C; Bareille, R; Rey, C

    2006-11-01

    The feasibility of making calcium carbonate-calcium phosphate (CaCO(3)-CaP) mixed cements, comprising at least 40% (w/w) CaCO(3) in the dry powder ingredients, has been demonstrated. Several original cement compositions were obtained by mixing metastable crystalline CaCO(3) phases with metastable amorphous or crystalline CaP powders in aqueous medium. The cements set within at most 1 h at 37 degrees C in atmosphere saturated with water. The hardened cement is microporous and exhibits weak compressive strength. The setting reaction appeared to be essentially related to the formation of a highly carbonated nanocrystalline apatite phase by reaction of the metastable CaP phase with part or almost all of the metastable CaCO(3) phase. The recrystallization of metastable CaP varieties led to a final cement consisting of a highly carbonated poorly crystalline apatite analogous to bone mineral associated with various amounts of vaterite and/or aragonite. The presence of controlled amounts of CaCO(3) with a higher solubility than that of the apatite formed in the well-developed CaP cements might be of interest to increase resorption rates in biomedical cement and favors its replacement by bone tissue. Cytotoxicity testing revealed excellent cytocompatibility of CaCO(3)-CaP mixed cement compositions.

  5. Molten carbonate fuel cell cathode with mixed oxide coating

    Science.gov (United States)

    Hilmi, Abdelkader; Yuh, Chao-Yi

    2013-05-07

    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.

  6. Performance simulation of planar SOFC using mixed hydrogen and carbon monoxide gases as fuel

    Energy Technology Data Exchange (ETDEWEB)

    Inui, Y. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan)]. E-mail: inui@eee.tut.ac.jp; Urata, A. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan); Ito, N. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan); Nakajima, T. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan); Tanaka, T. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi 441-8580 (Japan)

    2006-08-15

    The authors investigate in detail the influence of the mixing ratio of hydrogen and carbon monoxide in the fuel on the cell performance of the SOFC through numerical simulations for a single cell plate of the co-flow type planar cell. It is made clear that the cell performance is almost the same and excellent, independent of the mixing ratio of hydrogen and carbon monoxide under the nominal operating condition. The electromotive force of the hydrogen rich fuel gas is a little higher than that of the carbon monoxide rich fuel gas. The internal voltage drop in the cell decreases as the fraction of carbon monoxide becomes high. Since the value of the single cell voltage is determined by the balance of these two phenomena, the lowering of the electromotive force is dominant and the single cell voltage of the hydrogen rich fuel gas is higher when the inlet gas temperature is high, whereas the voltage drop reduction is dominant and the single cell voltage of the carbon monoxide rich fuel gas is higher when the temperature is low. The effect of the additional gases of water vapor and carbon dioxide is restricted to the single cell voltage shift, and the qualitative dependence of the single cell voltage on the inlet gas temperature is determined by the mixing ratio of hydrogen and carbon monoxide.

  7. Performance simulation of planar SOFC using mixed hydrogen and carbon monoxide gases as fuel

    International Nuclear Information System (INIS)

    Inui, Y.; Urata, A.; Ito, N.; Nakajima, T.; Tanaka, T.

    2006-01-01

    The authors investigate in detail the influence of the mixing ratio of hydrogen and carbon monoxide in the fuel on the cell performance of the SOFC through numerical simulations for a single cell plate of the co-flow type planar cell. It is made clear that the cell performance is almost the same and excellent, independent of the mixing ratio of hydrogen and carbon monoxide under the nominal operating condition. The electromotive force of the hydrogen rich fuel gas is a little higher than that of the carbon monoxide rich fuel gas. The internal voltage drop in the cell decreases as the fraction of carbon monoxide becomes high. Since the value of the single cell voltage is determined by the balance of these two phenomena, the lowering of the electromotive force is dominant and the single cell voltage of the hydrogen rich fuel gas is higher when the inlet gas temperature is high, whereas the voltage drop reduction is dominant and the single cell voltage of the carbon monoxide rich fuel gas is higher when the temperature is low. The effect of the additional gases of water vapor and carbon dioxide is restricted to the single cell voltage shift, and the qualitative dependence of the single cell voltage on the inlet gas temperature is determined by the mixing ratio of hydrogen and carbon monoxide

  8. Mixed carbonate-siliciclastic sedimentation on a tectonically active margin: Example from the Pliocene of Baja California Sur, Mexico

    Science.gov (United States)

    Dorsey, Rebecca J.; Kidwell, Susan M.

    1999-10-01

    Bioclast-rich, coarse-grained deposits in the Pliocene Loreto basin provide a record of mixed carbonate and siliciclastic sedimentation at the steep hanging-wall margin of this small, fault-controlled basin. Sedimentary facies consist of sand- to gravel-sized carbonate debris mixed with volcaniclastic sand and gravel in a proximal to distal facies tract that includes matrix-rich and matrix-poor shelly conglomerate, impure calcirudite and calcarenite, mixed-composition turbidites, and bioturbated calcarenitic sandstone. Carbonate material was produced by mollusks and other benthic organisms on a narrow, high-energy shelf and mixed with volcaniclastic sand and gravel in cross-shelf channels. These mixtures were transported down a steep subaqueous slope by debris flows, grain flows, and turbidity currents, forming foresets and bottomsets of marine Gilbert-type deltas. This style of mixed carbonate-siliciclastic sedimentation has not been documented in detail elsewhere but should be locally abundant in the stratigraphic record of fault-bounded basins, particularly those with cool or nutrient-rich waters that support relatively few binding and framework-building faunas. Recognition of similar facies in other settings can provide useful insights into ancient conditions of carbonate production, oceanography, climate, and tectonics.

  9. MODEL OF HYDRODYNAMIC MIXING OF CARBONIC POWDERS IN VACUUMATOR, USED IN STEEL-MAKING OF RUP “BMZ”

    Directory of Open Access Journals (Sweden)

    A. N. Chichko

    2005-01-01

    Full Text Available The mathematical model of the mixing and dissolving process of carbonic powder in a system '"vacuumator-bowl” under influence of circulating argon is offered. The spatial distribution of hydrodynamic currents at mixing of carbonic powder, received on the basis of computer calculations is presented. The character of distribution of hydrodynamic speeds of melt (circulating currents in industrial bowl and vacuumator for different time slots of mixing is determined. 

  10. In situ application of activated carbon and biochar to PCB-contaminated soil and the effects of mixing regime

    International Nuclear Information System (INIS)

    Denyes, Mackenzie J.; Rutter, Allison; Zeeb, Barbara A.

    2013-01-01

    The in situ use of carbon amendments such as activated carbon (AC) and biochar to minimize the bioavailability of organic contaminants is gaining in popularity. In the first in situ experiment conducted at a Canadian PCB-contaminated Brownfield site, GAC and two types of biochar were statistically equal at reducing PCB uptake into plants. PCB concentrations in Cucurbita pepo root tissue were reduced by 74%, 72% and 64%, with the addition of 2.8% GAC, Burt's biochar and BlueLeaf biochar, respectively. A complementary greenhouse study which included a bioaccumulation study of Eisenia fetida (earthworm), found mechanically mixing carbon amendments with PCB-contaminated soil (i.e. 24 h at 30 rpm) resulted in shoot, root and worm PCB concentrations 66%, 59% and 39% lower than in the manually mixed treatments (i.e. with a spade and bucket). Therefore, studies which mechanically mix carbon amendments with contaminated soil may over-estimate the short-term potential to reduce PCB bioavailability. Highlights: •Biochar and GAC reduced PCB uptake into plants and earthworms. •Biochar offered additional benefits, including increased plant and earthworm biomass. •BSAF reductions are greater when amendments are mechanically vs. manually mixed. •Mechanically mixing carbon amendments may over-estimate their remediation potential. -- In situ AC and biochar soil amendments perform equally well at reducing PCB uptake, however, laboratory-based mixing methods may exaggerate the sorptive capacities of both amendments

  11. Kinetic of formation for single carbon dioxide and mixed carbon dioxide and tetrahydrofuran hydrates in water and sodium chloride aqueous solution

    NARCIS (Netherlands)

    Sabil, K.M.; Duarte, A.R.C.; Zevenbergen, J.F.; Ahmad, M.M.; Yusup, S.; Omar, A.A.; Peters, C.J.

    2010-01-01

    A laboratory-scale reactor system is built and operated to measure the kinetic of formation for single and mixed carbon dioxide-tetrahydrofuran hydrates. The T-cycle method, which is used to collect the kinetic data, is briefly discussed. For single carbon dioxide hydrate, the induction time

  12. Multiple scattering of light by water cloud droplets with external and internal mixing of black carbon aerosols

    International Nuclear Information System (INIS)

    Wang Hai-Hua; Sun Xian-Ming

    2012-01-01

    The mixture of water cloud droplets with black carbon impurities is modeled by external and internal mixing models. The internal mixing model is modeled with a two-layered sphere (water cloud droplets containing black carbon (BC) inclusions), and the single scattering and absorption characteristics are calculated at the visible wavelength of 0.55 μm by using the Lorenz—Mie theory. The external mixing model is developed assuming that the same amount of BC particles are mixed with the water droplets externally. The multiple scattering characteristics are computed by using the Monte Carlo method. The results show that when the size of the BC aerosol is small, the reflection intensity of the internal mixing model is bigger than that of the external mixing model. However, if the size of the BC aerosol is big, the absorption of the internal mixing model will be larger than that of the external mixing model. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  13. Dissolved carbon dynamics in the freshwater-saltwater mixing zone of a coastal river entering the Northern Gulf of Mexico

    Science.gov (United States)

    He, S.; Xu, Y. J.

    2017-12-01

    Estuaries play an important role in the dynamics of dissolved carbon from freshwater to marine systems. This study aims to determine how dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) concentrations change along an 88-km long estuarine river with salinity ranging from 0.02 to 29.50. The study is expected to elucidate which processes most likely control carbon dynamics in a freshwater-saltwater mixing system, and to evaluate the net metabolism of this estuary using mixing curves and stable isotope analyses. From November 2014 to February 2016, water samples were collected and in-situ measurements on ambient water conditions were performed during eighteen field trips at six sites from upstream to downstream of the Calcasieu River, which enters the Northern Gulf of Mexico in the southern United States. δ13CDIC and δ13CDOC were measured from May 2015 to February 2017 during five of the field trips. The DIC concentration and δ13CDIC increased rapidly with increasing salinity in the mixing zone. The DIC concentrations appeared to be largely influenced by conservative mixing. The δ13CDIC values were close to those suggested by the conservative mixing model for May 2015, June 2015 and November 2015, but lower than those for July 2015 and February 2016, suggesting that an estuarine river can fluctuate from a balanced to a heterotrophic system (i.e., production/respiration aquatic photosynthesis from carbon produced by terrestrial photosynthesis in a river-ocean continuum. These findings suggest that riverine dissolved carbon undergoes a rapid change in freshwater-saltwater mixing, and that these dynamics should be taken into account in carbon processing and budgeting in the world's estuarine systems.

  14. Isopycnal mixing by mesoscale eddies significantly impacts oceanic anthropogenic carbon uptake

    Science.gov (United States)

    Gnanadesikan, Anand; Pradal, Marie-Aude; Abernathey, Ryan

    2015-06-01

    Anthropogenic carbon dioxide uptake varies across Earth System Models for reasons that have remained obscure. When varied within a single model, the lateral eddy mixing coefficient ARedi produces a range of uptake similar to the modeled range. The highest uptake, resulting from a simulation with a constant ARedi of 2400 m2/s, simulates 15% more historical carbon uptake than a model with ARedi = 400 m2/s. A sudden doubling in carbon dioxide produces a 21% range in carbon uptake across the models. Two spatially dependent representations of ARedi produce uptake that lies in the middle of the range of constant values despite predicting very large values in the subtropical gyres. One-dimensional diffusive models of the type used for integrated assessments can be fit to the simulations, with ARedi accounting for a substantial fraction of the effective vertical diffusion. Such models, however, mask significant regional changes in stratification and biological carbon storage.

  15. Studies of Carbonization Process on the Production of Durian Peel Biobriquettes with Mixed Biomass Coconut and Palm Shells

    Science.gov (United States)

    Sari, Ellyta; Pasymi; Khatab, Umar; Desmiarti, Reni; Ariansyah, Rian; Hariadi; Sutra

    2018-03-01

    Biobriquettes as alternative energy that can replace the role of kerosene. Biobriquettes made from agricultural waste biomass. Biobriquettes durian peel has been researched and developed continuously to obtain optimal quality in terms of calorific value, compressive strength and duration of ignition. In making durian peel biobriquettes needed other biomass mix to sustain duration of Ignition for biobriquettes durian skin quickly burned out. Stages of making biobriquettes durian skin are: material of drying, carbonization of biomass, grinding, mixing with adhesives, and printing. Carbonization process is a process that is important in obtaining the biomass charcoal. Carbonization is done by means of karbonisator pyrolysis. The purpose of this research is to study the process of carbonization to obtain biobriquettes durian skin that of quality in terms of value compressive strength, calorific value, and duration of ignition. Variations that done was kind mix of biomass,coconut shells and palm shells with the massa ratio 2 : 1, type of adhesive used tapioca powder and banana peels, carbonization of temperature 200°C. 300°C and 400 °C. The results showed that the highest compressive strength of the durian skin with a mixture of coconut shell and adhesive tapioca powder and carbonization temperature of 300 °C namely 12,7 g/cm2. The calorific value of the highest on the mix of skin durian with coconut shells and adhesive banana skin with temperature of carbonization 400 °C ie 6040 cal/g, and duration of ignition highest on a mixture of skin durian with coconut shell and adhesive banana skin at a temperature of carbonization 300 °C is 73 minutes.

  16. Complexation/encapsulation of green tea polyphenols in mixed calcium carbonate and phosphate micro-particles.

    Science.gov (United States)

    Elabbadi, Amal; Jeckelmann, Nicolas; Haefliger, Olivier P; Ouali, Lahoussine

    2011-01-01

    We used a double-jet mixer to encapsulate water-soluble polyphenols, green tea extract (GTE), with calcium-based inorganic materials. The device mixed calcium chloride solutions with a solution of carbonate and phosphate in the presence of a GTE solution, and formed micro-particles which capture the GTE molecules. The micro-particles were analysed by liquid chromatography coupled to tandem mass spectroscopy to determine the encapsulation yield and loading of the different GTE components. We established correlations between (1) the efficiency of the GTE encapsulation and the composition of the mixed anion solutions and (2) the protonation degree of the ions and the molar ratio of calcium cations and carbonate/phosphate anions. An optimal and reproducible GTE loading of about 40% with an encapsulation yield of 65% was observed for a carbonate/phosphate molar composition of 4 : 1. In addition, our experimental results showed that the process is selective and favours the encapsulation of gallated species which form stronger complexes with calcium cations.

  17. Preparation and Characterization of Various Activated Carbons Derived From Mixed Precursors Using Phosphoric Acid

    International Nuclear Information System (INIS)

    Daifullah, A.A.M.; Sharaf El-Deen, S.E.A.; Elkhalafawy, A.; Shehata, F.A.; Mahmoud, W.H.

    2008-01-01

    Rice straw (RS) and rice husk (RH), a low-cost agricultural by-products, have been used as a mixed precursor (i.e., RS mixed with RH in 1:1; 1:3 and 3:1 ratios) for the production of novel carbons using phosphoric acid as chemical activation. The raw materials were impregnated with 50% and 70% H 3 PO 4 followed by activation at 500 degree C. The latter proved to be the most effective in producing active carbon with good adsorptive capacity. The resulting carbons were characterized by elemental analysis, infrared spectroscopy, density, SEM and S BET . In general, the resulting carbons showed reasonable surface areas with mainly micropore structure. The adsorption capacity was demonstrated by the isotherms of methylene blue (MB), phenol and iodine from aqueous solution. The adsorption data was found to conform with the Langmuir equation with the concentration range studied, and the monolayer coverage was determined for each of the samples. It was found that surface area is mainly attributed to micropore volume so that phenol adsorption and iodine number correspond well with surface area determined by nitrogen adsorption

  18. Carbon Nano tubes Based Mixed Matrix Membrane for Gas Separation

    International Nuclear Information System (INIS)

    Sanip, S.M.; Ismail, A.F.; Goh, P.S.; Norrdin, M.N.A.; Soga, T.; Tanemura, M.; Yasuhiko, H.

    2011-01-01

    Carbon nano tubes based mixed matrix membrane (MMM) was prepared by the solution casting method in which the functionalized multi walled carbon nano tubes (f-MWNTs) were embedded into the polyimide membrane and the resulting membranes were characterized. The effect of nominal MWNTs content between 0.5 and 1.0 wt % on the gas separation properties were looked into. The morphologies of the MMM also indicated that at 0.7 % loading of f- MWNTs, the structures of the MMM showed uniform finger-like structures which have facilitated the fast gas transport through the polymer matrix. It may also be concluded that addition of open ended and shortened MWNTs to the polymer matrix can improve its permeability by increasing diffusivity through the MWNTs smooth cavity. (author)

  19. Role of ocean isopycnal mixing in setting the uptake of anthropogenic carbon

    Science.gov (United States)

    Gnanadesikan, A.; Pradal, M. A. S.; Abernathey, R. P.

    2014-12-01

    The magnitude of the isopycnal stirring coefficient ARedi is poorly constrained from data and varies greatly across Earth System Models. This paper documents the impact of such uncertainty on the oceanic carbon cycle. We compare six spatial representations of ARedi. Four constant values (400, 800, 1200 and 2400 m2/s) are used to explore the difference between using the low values found in many models and the higher values seen in observational estimates. Models are also run with two spatially dependent values of ARedi based on altimetry, one which captures the fully two-dimensional structure of the mixing coefficient, the other of which looks at the zonally averaged structure alone. Under global warming significant changes are seen in the biological pump in convective regions, but these changes are largely locally compensated by changes in preformed DIC. Instead, differences in anthropogenic uptake of carbon are largely centered in the tropics, and can be well described in terms of a relatively simple diffusive approximation. Using ideal age as a tracer can give insight into the expected behavior of the models. The rate of oceanic mixing represents a quantitatively significant uncertainty in future projections of the global carbon cycle, amounting to about 20% of the oceanic uptake.

  20. Long-term progress prediction for the carbon steel corrosion in diluted artificial seawater with and without zinc / sodium carbonate mixed phosphate

    International Nuclear Information System (INIS)

    Fujii, Kazumi; Ishioka, Shinichi; Iwanami, Masaru; Kaneko, Tetsuji; Tanaka, Norihiko; Kawaharada, Yoshiyuki; Yokoyama, Yutaka; Umehara, Ryuji; Kato, Chiaki; Ueno, Fumiyoshi; Fukaya, Yuichi; Kumaga, Katsuhiko

    2017-01-01

    The Fukushima Daiichi Nuclear Power Plants (1F) were damaged by an unprecedented severe accident in the great east Japan earthquake on 11th, March, 2011, and seawater and fresh water were injected as an emergency countermeasure for the core cooling. The primary containment vessels (PCVs), made of carbon steel, were exposed to seawater and fresh water, and have had the possibility of corrosion. The PCVs of 1F are the most important equipment for the core cooling and removal of the fuel debris, the structural integrity of the PCV must be maintained until decommissioning. Therefore, evaluation of PCV carbon steel corrosion behavior is important, as well as evaluation of corrosion inhibitors as one of the corrosion protection methods. In this study, long-term immersion corrosion tests for up to 10000 hours were performed in diluted artificial seawater simulating 1F with and without zinc / sodium carbonate mixed phosphate. Based on the long-term immersion corrosion test results, diagnosis method of the reduction in plate thickness of the nuclear vessel was examined. The validity of the existing corrosion progress models following parabolic rate law was confirmed. The corrosion progress models were also applicable to the corrosion inhibited condition adding zinc / sodium carbonate mixed phosphate. It was found that the corrosion rate of carbon steel drastically fell down by adding this corrosion inhibitor. (author)

  1. Black carbon mixing state impacts on cloud microphysical properties: effects of aerosol plume and environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ching, Ping Pui; Riemer, Nicole; West, Matthew

    2016-05-27

    Black carbon (BC) is usually mixed with other aerosol species within individual aerosol particles. This mixture, along with the particles' size and morphology, determines the particles' optical and cloud condensation nuclei properties, and hence black carbon's climate impacts. In this study the particle-resolved aerosol model PartMC-MOSAIC was used to quantify the importance of black carbon mixing state for predicting cloud microphysical quantities. Based on a set of about 100 cloud parcel simulations a process level analysis framework was developed to attribute the response in cloud microphysical properties to changes in the underlying aerosol population ("plume effect") and the cloud parcel cooling rate ("parcel effect"). It shows that the response of cloud droplet number concentration to changes in BC emissions depends on the BC mixing state. When the aerosol population contains mainly aged BC particles an increase in BC emission results in increasing cloud droplet number concentrations ("additive effect"). In contrast, when the aerosol population contains mainly fresh BC particles they act as sinks for condensable gaseous species, resulting in a decrease in cloud droplet number concentration as BC emissions are increased ("competition effect"). Additionally, we quantified the error in cloud microphysical quantities when neglecting the information on BC mixing state, which is often done in aerosol models. The errors ranged from -12% to +45% for the cloud droplet number fraction, from 0% to +1022% for the nucleation-scavenged black carbon (BC) mass fraction, from -12% to +4% for the effective radius, and from -30% to +60% for the relative dispersion.

  2. A mechanistic model of an upper bound on oceanic carbon export as a function of mixed layer depth and temperature

    Directory of Open Access Journals (Sweden)

    Z. Li

    2017-11-01

    Full Text Available Export production reflects the amount of organic matter transferred from the ocean surface to depth through biological processes. This export is in large part controlled by nutrient and light availability, which are conditioned by mixed layer depth (MLD. In this study, building on Sverdrup's critical depth hypothesis, we derive a mechanistic model of an upper bound on carbon export based on the metabolic balance between photosynthesis and respiration as a function of MLD and temperature. We find that the upper bound is a positively skewed bell-shaped function of MLD. Specifically, the upper bound increases with deepening mixed layers down to a critical depth, beyond which a long tail of decreasing carbon export is associated with increasing heterotrophic activity and decreasing light availability. We also show that in cold regions the upper bound on carbon export decreases with increasing temperature when mixed layers are deep, but increases with temperature when mixed layers are shallow. A meta-analysis shows that our model envelopes field estimates of carbon export from the mixed layer. When compared to satellite export production estimates, our model indicates that export production in some regions of the Southern Ocean, particularly the subantarctic zone, is likely limited by light for a significant portion of the growing season.

  3. Hydrogen role in a carbon-free energy mix

    International Nuclear Information System (INIS)

    2014-02-01

    Among the energy storage technologies under development today, there is today an increasing interest towards the hydrogen-based ones. Hydrogen generation allows to store electricity, while its combustion can supply electrical, mechanical or heat energy. The French Atomic Energy Commission (CEA) started to work on hydrogen technologies at the end of the 1990's in order to reinforce its economical interest. The development of these technologies is one of the 34 French industrial programs presented in September 2013 by the French Minister of productive recovery. This paper aims at identifying the hydrogen stakes in a carbon-free energy mix and at highlighting the remaining technological challenges to be met before reaching an industrial development level

  4. Attempts at estimating mixed venous carbon dioxide tension by the single-breath method.

    Science.gov (United States)

    Ohta, H; Takatani, O; Matsuoka, T

    1989-01-01

    The single-breath method was originally proposed by Kim et al. [1] for estimating the blood carbon dioxide tension and cardiac output. Its reliability has not been proven. The present study was undertaken, using dogs, to compare the mixed venous carbon dioxide tension (PVCO2) calculated by the single-breath method with the PVCO2 measured in mixed venous blood, and to evaluate the influence of variations in the exhalation duration and the volume of expired air usually discarded from computations as the deadspace. Among the exhalation durations of 15, 30 and 45 s tested, the 15 s duration was found to be too short to obtain an analyzable O2-CO2 curve, but at either 30 or 45 s, the calculated values of PVCO2 were comparable to the measured PVCO2. A significant agreement between calculated and measured PVCO2 was obtained when the expired gas with PCO2 less than 22 Torr was considered as deadspace gas.

  5. Distribution and mixing of old and new nonstructural carbon in two temperate trees.

    Science.gov (United States)

    Richardson, Andrew D; Carbone, Mariah S; Huggett, Brett A; Furze, Morgan E; Czimczik, Claudia I; Walker, Jennifer C; Xu, Xiaomei; Schaberg, Paul G; Murakami, Paula

    2015-04-01

    We know surprisingly little about whole-tree nonstructural carbon (NSC; primarily sugars and starch) budgets. Even less well understood is the mixing between recent photosynthetic assimilates (new NSC) and previously stored reserves. And, NSC turnover times are poorly constrained. We characterized the distribution of NSC in the stemwood, branches, and roots of two temperate trees, and we used the continuous label offered by the radiocarbon (carbon-14, (14) C) bomb spike to estimate the mean age of NSC in different tissues. NSC in branches and the outermost stemwood growth rings had the (14) C signature of the current growing season. However, NSC in older aboveground and belowground tissues was enriched in (14) C, indicating that it was produced from older assimilates. Radial patterns of (14) C in stemwood NSC showed strong mixing of NSC across the youngest growth rings, with limited 'mixing in' of younger NSC to older rings. Sugars in the outermost five growth rings, accounting for two-thirds of the stemwood pool, had a mean age  5 yr. Our results are thus consistent with a previously-hypothesized two-pool ('fast' and 'slow' cycling NSC) model structure. These pools appear to be physically distinct. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  6. Carbon capture from natural gas using multi-walled CNTs based mixed matrix membranes.

    Science.gov (United States)

    Hussain, Abid; Farrukh, Sarah; Hussain, Arshad; Ayoub, Muhammad

    2017-12-05

    Most of the polymers and their blends, utilized in carbon capture membranes, are costly, but cellulose acetate (CA) being inexpensive is a lucrative choice. In this research, pure and mixed matrix membranes (MMMs) have been fabricated to capture carbon from natural gas. Polyethylene glycol (PEG) has been utilized in the fabrication of membranes to modify the chain flexibility of polymers. Multi-walled carbon nanotubes (MWCNTs) provide mechanical strength, thermal stability, an extra free path for CO 2 molecules and augment CO 2 /CH 4 selectivity. Membranes of pure CA, CA/PEG blend of different PEG concentrations (5%, 10%, 15%) and CA/PEG/MWCNTs blend of 10% PEG with different MWCNTs concentrations (5%, 10%, 15%) were prepared in acetone using solution casting techniques. Fabricated membranes were characterized using SEM, TGA and tensile testing. Permeation results revealed remarkable improvement in CO 2 /CH 4 selectivity. In single gas experiments, CO 2 /CH 4 selectivity is enhanced 8 times for pure membranes containing 10% PEG and 14 times for MMMs containing 10% MWCNTs. In mix gas experiments, the CO 2 /CH 4 selectivity is increased 13 times for 10% PEG and 18 times for MMMs with 10% MWCNTs. Fabricated MMMs have a tensile strength of 13 MPa and are more thermally stable than CA membranes.

  7. Fuel Mix Impacts from Transportation Fuel Carbon Intensity Standards in Multiple Jurisdictions

    Science.gov (United States)

    Witcover, J.

    2017-12-01

    Fuel carbon intensity standards have emerged as an important policy in jurisdictions looking to target transportation greenhouse gas (GHG) emissions for reduction. A carbon intensity standard rates transportation fuels based on analysis of lifecycle GHG emissions, and uses a system of deficits and tradable, bankable credits to reward increased use of fuels with lower carbon intensity ratings while disincentivizing use of fuels with higher carbon intensity ratings such as conventional fossil fuels. Jurisdictions with carbon intensity standards now in effect include California, Oregon, and British Columbia, all requiring 10% reductions in carbon intensity of the transport fuel pool over a 10-year period. The states and province have committed to grow demand for low carbon fuels in the region as part of collaboration on climate change policies. Canada is developing a carbon intensity standard with broader coverage, for fuels used in transport, industry, and buildings. This study shows a changing fuel mix in affected jurisdictions under the policy in terms of shifting contribution of transportation energy from alternative fuels and trends in shares of particular fuel pathways. It contrasts program designs across the jurisdictions with the policy, highlights the opportunities and challenges these pose for the alternative fuel market, and discusses the impact of having multiple policies alongside federal renewable fuel standards and sometimes local carbon pricing regimes. The results show how the market has responded thus far to a policy that incentivizes carbon saving anywhere along the supply chain at lowest cost, in ways that diverged from a priori policy expectations. Lessons for the policies moving forward are discussed.

  8. 1 Mixing state and absorbing properties of black carbon during Arctic haze

    Science.gov (United States)

    Zanatta, Marco; Gysel, Martin; Eleftheriadis, Kosas; Laj, Paolo; Hans-Werner, Jacobi

    2016-04-01

    The Arctic atmosphere is periodically affected by the Arctic haze occurring in spring. One of its particulate components is the black carbon (BC), which is considered to be an important contributor to climate change in the Arctic region. Beside BC-cloud interaction and albedo reduction of snow, BC may influence Arctic climate interacting directly with the solar radiation, warming the corresponding aerosol layer (Flanner, 2013). Such warming depends on BC atmospheric burden and also on the efficiency of BC to absorb light, in fact the light absorption is enhanced by mixing of BC with other atmospheric non-absorbing materials (lensing effect) (Bond et al., 2013). The BC reaching the Arctic is evilly processed, due to long range transport. Aging promote internal mixing and thus absorption enhancement. Such modification of mixing and is quantification after long range transport have been observed in the Atlantic ocean (China et al., 2015) but never investigated in the Arctic. During field experiments conducted at the Zeppelin research site in Svalbard during the 2012 Arctic spring, we investigated the relative precision of different BC measuring techniques; a single particle soot photometer was then used to assess the coating of Arctic black carbon. This allowed quantifying the absorption enhancement induced by internal mixing via optical modelling; the optical assessment of aged black carbon in the arctic will be of major interest for future radiative forcing assessment.Optical characterization of the total aerosol indicated that in 2012 no extreme smoke events took place and that the aerosol population was dominated by fine and non-absorbing particles. Low mean concentration of rBC was found (30 ng m-3), with a mean mass equivalent diameter above 200 nm. rBC concentration detected with the continuous soot monitoring system and the single particle soot photometer was agreeing within 15%. Combining absorption coefficient observed with an aethalometer and rBC mass

  9. Convective mixing length and the galactic carbon to oxygen ratio

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, A; Peimbert, M [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1981-01-01

    We have studied chemical evolution models, assuming instantaneous recycling, and considering: a) the effects of mass loss both in massive stars and in intermediate mass stars, and b) the initial mass function of the solar neighbourhood (Serrano 1978). From these models we have derived the yields of carbon and oxygen. It is concluded that the condition C/O approximately 0.58 in the solar neighbourhood can only be satisfied if, during advanced stages of stellar evolution of intermediate mass stars, the ratio of the convective mixing length to the pressure scale height is > approximately 2.

  10. Utilization of poly(methyl methacrylate) – carbon nanotube and polystyrene – carbon nanotube in situ polymerized composites as masterbatches for melt mixing

    OpenAIRE

    M. Lahelin; M. Annala; J. Seppala

    2012-01-01

    Carbon nanotubes (CNTs) were melt mixed directly or by using an in situ polymerized masterbatch into a matrix polymer, polystyrene (PS) or poly(methyl methacrylate) (PMMA). The mechanical properties of the composites were mostly determined by the amount of CNTs, and not by the use of directly melt mixed CNTs or the use of the masterbatch. In contrast, the electrical resistivity of the composites was dependent on the manner in which the CNTs were added to the matrix polymer. When there was inc...

  11. Characterization of Black Carbon Mixing State Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Davidovits, P. [Boston College, Chestnut Hill, MA (United States); Lewis, E. R. [Brookhaven National Lab. (BNL), Upton, NY (United States); Onasch, T. B. [Aerodyne Research, Billerica, MA (United States)

    2016-04-01

    Interpreting the temporal relationship between the scattering and incandescence signals recorded by the Single Particle Soot Photometer (SP2), Sedlacek et al. (2012) reported that 60% of the refractory black carbon containing particles in a plume containing biomass burning tracers exhibited non-core-shell structure. Because the relationship between the rBC (refractory black carbon) incandescence and the scattering signals had not been reported in the peer-reviewed literature, and to further evaluate the initial interpretation by Sedlacek et al., a series of experiments was undertaken to investigate black carbon-containing particles of known morphology using Regal black (RB), a proxy for collapsed soot, as the light-absorbing substance to characterize this signal relationship. Particles were formed by coagulation of RB with either a solid substance (sodium chloride or ammonium sulfate) or a liquid substance (dioctyl sebacate), and by condensation with dioctyl sebacate, the latter experiment forming particles in a core-shell configuration. Each particle type experienced fragmentation (observed as negative lagtimes), and each yielded similar lagtime responses in some instances, confounding attempts to differentiate particle morphology using current SP2 lagtime analysis. SP2 operating conditions, specifically laser power and sample flow rate, which in turn affect the particle heating and dissipation rates, play an important role in the behavior of particles in the SP2, including probability of fragmentation. This behavior also depended on the morphology of the particles and on the thermochemical properties of the non-RB substance. Although these influences cannot currently be unambiguously separated, the SP2 analysis may still provide useful information on particle mixing states and black carbon particle sources. This work was communicated in a 2015 publication (Sedlacek et al. 2015)

  12. Modeling climate and fuel reduction impacts on mixed-conifer forest carbon stocks in the Sierra Nevada, California

    Science.gov (United States)

    Matthew D. Hurteau; Timothy A. Robards; Donald Stevens; David Saah; Malcolm North; George W. Koch

    2014-01-01

    Quantifying the impacts of changing climatic conditions on forest growth is integral to estimating future forest carbon balance. We used a growth-and-yield model, modified for climate sensitivity, to quantify the effects of altered climate on mixed-conifer forest growth in the Lake Tahoe Basin, California. Estimates of forest growth and live tree carbon stocks were...

  13. Assessment of phosphate binding by sevelamer carbonate powder for oral suspension mixed in foods.

    Science.gov (United States)

    Hanus, Martin; Zhorov, Eugene; Brommage, Deborah; Plone, Melissa; Holmes-Farley, Stephen Randall

    2012-01-01

    This study investigated mixing sevelamer carbonate powder with foods and beverages other than water. Food samples, including applesauce, oatmeal, chicken, protein powder, scrambled eggs, ginger ale, and diet ginger ale, were subjected to an in vitro assay, and the difference in the amount of phosphate bound between samples pre-exposed to foods and samples where the drug was exposed to foods concurrently was determined Under these assay conditions, pre-exposure to sevelamer carbonate powder had no effect on the ability to bind phosphate. Clinical testing is needed to further evaluate this finding.

  14. The effect of mixed oxidants and powdered activated carbon on the removal of natural organic matter.

    Science.gov (United States)

    Alvarez-Uriarte, Jon I; Iriarte-Velasco, Unai; Chimeno-Alanís, Noemí; González-Velasco, Juan R

    2010-09-15

    Present paper studies the influence of electrochemically generated mixed oxidants on the physicochemical properties of natural organic matter, and especially from the disinfection by-products formation point of view. The study was carried out in a full scale water treatment plant. Results indicate that mixed oxidants favor humic to non-humic conversion of natural organic matter. Primary treatment preferentially removes the more hydrophobic fraction. This converted the non-humic fraction in an important source of disinfection by-products with a 20% contribution to the final trihalomethane formation potential (THMFP(F)) of the finished water. Enhanced coagulation at 40 mg l(-1) of polyaluminium chloride with a moderate mixing intensity (80 rpm) and pH of 6.0 units doubled the removal efficiency of THMFP(F) achieved at full scale plant. However, gel permeation chromatography data revealed that low molecular weight fractions were still hardly removed. Addition of small amounts of powdered activated carbon, 50 mg l(-1), allowed reduction of coagulant dose by 50% whereas removal of THMFP(F) was maintained or even increased. In systems where mixed oxidants are used addition of powdered activated carbon allows complementary benefits by a further reduction in the THMFP(F) compared to the conventional only coagulation-flocculation-settling process. Copyright 2010 Elsevier B.V. All rights reserved.

  15. MATHEMATICAL SIMULATION OF ARGON MIXING PROCESSES AND STEEL SATURATION WITH CARBON IN LADLE

    Directory of Open Access Journals (Sweden)

    A. N. Chichko

    2006-01-01

    Full Text Available The mathematical model for dissolution process of a powder material in steel melt is proposed in the paper. The model permits to take into account mixing hydrodynamics on the basis of the Navier-Stokes equations. One of the industrial out-of-furnace treatment schemes taken as an example demonstrates the opportunities to model a carbon dissolution in a ladle.

  16. Transfer-free synthesis of graphene-like atomically thin carbon films on SiC by ion beam mixing technique

    Science.gov (United States)

    Zhang, Rui; Chen, Fenghua; Wang, Jinbin; Fu, Dejun

    2018-03-01

    Here we demonstrate the synthesis of graphene directly on SiC substrates at 900 °C using ion beam mixing technique with energetic carbon cluster ions on Ni/SiC structures. The thickness of 7-8 nm Ni films was evaporated on the SiC substrates, followed by C cluster ion bombarding. Carbon cluster ions C4 were bombarded at 16 keV with the dosage of 4 × 1016 atoms/cm2. After thermal annealing process Ni silicides were formed, whereas C atoms either from the decomposition of the SiC substrates or the implanted contributes to the graphene synthesis by segregating and precipitating process. The limited solubility of carbon atoms in silicides, involving SiC, Ni2Si, Ni5Si2, Ni3Si, resulted in diffusion and precipitation of carbon atoms to form graphene on top of Ni and the interface of Ni/SiC. The ion beam mixing technique provides an attractive production method of a transfer-free graphene growth on SiC and be compatible with current device fabrication.

  17. Biodegradability of carbon nanotube/polymer nanocomposites under aerobic mixed culture conditions.

    Science.gov (United States)

    Phan, Duc C; Goodwin, David G; Frank, Benjamin P; Bouwer, Edward J; Fairbrother, D Howard

    2018-10-15

    The properties and commercial viability of biodegradable polymers can be significantly enhanced by the incorporation of carbon nanotubes (CNTs). The environmental impact and persistence of these carbon nanotube/polymer nanocomposites (CNT/PNCs) after disposal will be strongly influenced by their microbial interactions, including their biodegradation rates. At the end of consumer use, CNT/PNCs will encounter diverse communities of microorganisms in landfills, surface waters, and wastewater treatment plants. To explore CNT/PNC biodegradation under realistic environmental conditions, the effect of multi-wall CNT (MWCNT) incorporation on the biodegradation of polyhydroxyalkanoates (PHA) was investigated using a mixed culture of microorganisms from wastewater. Relative to unfilled PHA (0% w/w), the MWCNT loading (0.5-10% w/w) had no statistically significant effect on the rate of PHA matrix biodegradation. Independent of the MWCNT loading, the extent of CNT/PNC mass remaining closely corresponded to the initial mass of CNTs in the matrix suggesting a lack of CNT release. CNT/PNC biodegradation was complete in approximately 20 days and resulted in the formation of a compressed CNT mat that retained the shape of the initial CNT/PNC. This study suggests that although CNTs have been shown to be cytotoxic towards a range of different microorganisms, this does not necessarily impact the biodegradation of the surrounding polymer matrix in mixed culture, particularly in situations where the polymer type and/or microbial population favor rapid polymer biodegradation. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. The primary results for the mixed carbon material used for high flux steady-state tokamak operation in China

    International Nuclear Information System (INIS)

    Guo, Q.G.; Li, J.G.; Zhai, G.T.; Liu, L.; Song, J.R.; Zhang, L.F.; He, Y.X.; Chen, J.L.

    2001-01-01

    Several types of carbon mixed materials have been developed in China to be used for high flux steady-state tokamak operation. Performance evaluation of these materials is necessary to determine their applicability as PFCs for high flux steady state. This paper describes the primary results of carbon mixed materials and the effects of dopants on properties are primarily discussed. Test results reveal that bulk boronized graphite has excellent physical and mechanical properties while their thermal conductivity is no more than 73 W/m K due to the formation of a uniform boron-carbon solid solution. In case of multi-element doped graphite, titanium dopant or a decreased boron content is favorable to enhance thermal conductivity. A kind of doped graphite has been developed with thermal conductivity as high as 278 W/m K by optimizing the compositions. Correlations among compositions, microstructure and properties of such doped graphite are discussed

  19. Mixed fuel strategy for carbon deposition mitigation in solid oxide fuel cells at intermediate temperatures.

    Science.gov (United States)

    Su, Chao; Chen, Yubo; Wang, Wei; Ran, Ran; Shao, Zongping; Diniz da Costa, João C; Liu, Shaomin

    2014-06-17

    In this study, we propose and experimentally verified that methane and formic acid mixed fuel can be employed to sustain solid oxide fuel cells (SOFCs) to deliver high power outputs at intermediate temperatures and simultaneously reduce the coke formation over the anode catalyst. In this SOFC system, methane itself was one part of the fuel, but it also played as the carrier gas to deliver the formic acid to reach the anode chamber. On the other hand, the products from the thermal decomposition of formic acid helped to reduce the carbon deposition from methane cracking. In order to clarify the reaction pathways for carbon formation and elimination occurring in the anode chamber during the SOFC operation, O2-TPO and SEM analysis were carried out together with the theoretical calculation. Electrochemical tests demonstrated that stable and high power output at an intermediate temperature range was well-maintained with a peak power density of 1061 mW cm(-2) at 750 °C. With the synergic functions provided by the mixed fuel, the SOFC was running for 3 days without any sign of cell performance decay. In sharp contrast, fuelled by pure methane and tested at similar conditions, the SOFC immediately failed after running for only 30 min due to significant carbon deposition. This work opens a new way for SOFC to conquer the annoying problem of carbon deposition just by properly selecting the fuel components to realize their synergic effects.

  20. Influence of litter diversity on dissolved organic matter release and soil carbon formation in a mixed beech forest.

    Science.gov (United States)

    Scheibe, Andrea; Gleixner, Gerd

    2014-01-01

    We investigated the effect of leaf litter on below ground carbon export and soil carbon formation in order to understand how litter diversity affects carbon cycling in forest ecosystems. 13C labeled and unlabeled leaf litter of beech (Fagus sylvatica) and ash (Fraxinus excelsior), characterized by low and high decomposability, were used in a litter exchange experiment in the Hainich National Park (Thuringia, Germany). Litter was added in pure and mixed treatments with either beech or ash labeled with 13C. We collected soil water in 5 cm mineral soil depth below each treatment biweekly and determined dissolved organic carbon (DOC), δ13C values and anion contents. In addition, we measured carbon concentrations and δ13C values in the organic and mineral soil (collected in 1 cm increments) up to 5 cm soil depth at the end of the experiment. Litter-derived C contributes less than 1% to dissolved organic matter (DOM) collected in 5 cm mineral soil depth. Better decomposable ash litter released significantly more (0.50±0.17%) litter carbon than beech litter (0.17±0.07%). All soil layers held in total around 30% of litter-derived carbon, indicating the large retention potential of litter-derived C in the top soil. Interestingly, in mixed (ash and beech litter) treatments we did not find a higher contribution of better decomposable ash-derived carbon in DOM, O horizon or mineral soil. This suggest that the known selective decomposition of better decomposable litter by soil fauna has no or only minor effects on the release and formation of litter-derived DOM and soil organic matter. Overall our experiment showed that 1) litter-derived carbon is of low importance for dissolved organic carbon release and 2) litter of higher decomposability is faster decomposed, but litter diversity does not influence the carbon flow.

  1. Carbon footprint of patient journeys through primary care: a mixed methods approach.

    Science.gov (United States)

    Andrews, Elizabeth; Pearson, David; Kelly, Charlotte; Stroud, Laura; Rivas Perez, Martin

    2013-09-01

    The NHS has a target of cutting its carbon dioxide (CO2) emissions by 80% below 1990 levels by 2050. Travel comprises 17% of the NHS carbon footprint. This carbon footprint represents the total CO2 emissions caused directly or indirectly by the NHS. Patient journeys have previously been planned largely without regard to the environmental impact. The potential contribution of 'avoidable' journeys in primary care is significant. To investigate the carbon footprint of patients travelling to and from a general practice surgery, the issues involved, and potential solutions for reducing patient travel. A mixed methods study in a medium-sized practice in Yorkshire. During March 2012, 306 patients completed a travel survey. GIS maps of patients' travel (modes and distances) were produced. Two focus groups (12 clinical and 13 non-clinical staff) were recorded, transcribed, and analysed using a thematic framework approach. The majority (61%) of patient journeys to and from the surgery were made by car or taxi; main reasons cited were 'convenience', 'time saving', and 'no alternative' for accessing the surgery. Using distances calculated via ArcGIS, the annual estimated CO2 equivalent carbon emissions for the practice totalled approximately 63 tonnes. Predominant themes from interviews related to issues with systems for booking appointments and repeat prescriptions; alternative travel modes; delivering health care; and solutions to reducing travel. The modes and distances of patient travel can be accurately determined and allow appropriate carbon emission calculations for GP practices. Although challenging, there is scope for identifying potential solutions (for example, modifying administration systems and promoting walking) to reduce 'avoidable' journeys and cut carbon emissions while maintaining access to health care.

  2. Forecasting carbon dioxide emissions based on a hybrid of mixed data sampling regression model and back propagation neural network in the USA.

    Science.gov (United States)

    Zhao, Xin; Han, Meng; Ding, Lili; Calin, Adrian Cantemir

    2018-01-01

    The accurate forecast of carbon dioxide emissions is critical for policy makers to take proper measures to establish a low carbon society. This paper discusses a hybrid of the mixed data sampling (MIDAS) regression model and BP (back propagation) neural network (MIDAS-BP model) to forecast carbon dioxide emissions. Such analysis uses mixed frequency data to study the effects of quarterly economic growth on annual carbon dioxide emissions. The forecasting ability of MIDAS-BP is remarkably better than MIDAS, ordinary least square (OLS), polynomial distributed lags (PDL), autoregressive distributed lags (ADL), and auto-regressive moving average (ARMA) models. The MIDAS-BP model is suitable for forecasting carbon dioxide emissions for both the short and longer term. This research is expected to influence the methodology for forecasting carbon dioxide emissions by improving the forecast accuracy. Empirical results show that economic growth has both negative and positive effects on carbon dioxide emissions that last 15 quarters. Carbon dioxide emissions are also affected by their own change within 3 years. Therefore, there is a need for policy makers to explore an alternative way to develop the economy, especially applying new energy policies to establish a low carbon society.

  3. Combined electrochemical degradation and activated carbon adsorption treatments for wastewater containing mixed phenolic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Rajkumar, D.; Palanivelu, K.; Balasubramanian, N. [Anna University, Madras (India). Center for Environmental Studies

    2005-01-01

    Electrochemical degradation of mixed phenolic compounds present in coal conversion wastewater was investigated in the presence of chloride as supporting electrolyte. Initially, the degradation experiments were conducted separately with 300 mg/L of individual phenolic compound in the presence of 2500 mg/L chloride using Ti/TiO{sub 2}-RuO{sub 2}-IrO{sub 2} anode at 5.4 A/dm{sup 2} current density. Comparison of the experimental results of the chemical oxygen demand (COD) removal versus charge indicated that the order of decreasing COD removal for various phenolic compounds as catechol {gt} resorcinol {gt} m-cresol {gt} o-cresol {gt} phenol {gt} p-cresol. Degradation of the mixture of phenolic compounds and high-pressure liquid chromatography (HPLC) determinations at various stages of electrolysis showed that phenolic compounds were initially converted into benzoquinone and then to lower molecular weight aliphatic compounds. The COD and the total organic carbon (TOC) removal were 83 and 58.9% after passing 32 Ah/L with energy consumption of 191.6 kWh/kg of COD removal. Experiments were also conducted to remove adsorbable organic halogens (AOX) content in the treated solution using granular activated carbon. The optimum conditions for the removal of AOX was at pH 3.0, 5 mL/min flow rate and 31.2 cm bed height. Based on the investigation, a general scheme of treatment of mixed phenolic compounds by combined electrochemical and activated carbon adsorption treatment is proposed.

  4. European transition to a low carbon electricity system using a mix of variable renewable energies: carbon saving trajectories as functions of production and storage capacity.

    Science.gov (United States)

    Francois, Baptiste; Creutin, Jean-Dominique

    2016-04-01

    Today, most of the produced energy is generated from fossil energy sources (i.e. coal, petroleum). As a result, the energy sector is still the main source of greenhouse gas in the atmosphere. For limiting greenhouse gas emission, a transition from fossil to renewable energy is required, increasing gradually the fraction energy coming from variable renewable energy (i.e. solar power, wind power and run-of-the river hydropower, hereafter denoted as VRE). VRE penetration, i.e. the percentage of demand satisfied by variable renewables assuming no storage capacity, is hampered by their variable and un-controllable features. Many studies show that combining different VRE over space smoothes their variability and increases their global penetration by a better match of demand fluctuations. When the demand is not fully supplied by the VRE generation, backup generation is required from stored energy (mostly from dams) or fossil sources, the latter being associated with high greenhouse gas emission. Thus the VRE penetration is a direct indicator of carbon savings and basically depends on the VRE installed capacity, its mix features, and on the installed storage capacity. In this study we analyze the European transition to a low carbon electricity system. Over a selection of representative regions we analyze carbon saving trajectories as functions of VRE production and storage capacities for different scenarios mixing one to three VRE with non-renewables. We show substantial differences between trajectories when the mix of sources is far from the local optimums, when the storage capacity evolves. We bring new elements of reflection about the effect of transport grid features from local independent systems to a European "copper plate". This work is part of the FP7 project COMPLEX (Knowledge based climate mitigation systems for a low carbon economy; Project FP7-ENV-2012 number: 308601; http://www.complex.ac.uk/).

  5. Measuring and modeling carbon balance in mountainous Northern Rocky mixed conifer forests

    Science.gov (United States)

    Hudiburg, T. W.; Berardi, D.; Stenzel, J.

    2016-12-01

    Drought and wildfire caused by changing precipitation patterns, increased temperatures, increased fuel loads, and decades of fire suppression are reducing forest carbon uptake from local to continental scales. This trend is especially widespread in Idaho and the intermountain west and has important implications for climate change and forest management options. Given the key role of forests in climate regulation, understanding forest response to drought and the feedbacks to the atmosphere is a key research and policy-relevant priority globally. As temperature, fire, and precipitation regimes continue to change and there is increased risk of forest mortality, measurements and modeling at temporal and spatial scales that are conducive to understanding the impacts and underlying mechanisms of carbon and nutrient cycling become critically important. Until recently, sub-daily measurements of ecosystem carbon balance have been limited in remote, mountainous terrain (e.g Northern Rocky mountain forests). Here, we combine new measurement technology and state-of-the-art ecosystem modeling to determine the impact of drought on the total carbon balance of a mature, mixed-conifer forest in Northern Idaho. Our findings indicate that drought had no impact on aboveground NPP, despite early growing season reductions in soil moisture and fine root biomass compared to non-drought years in the past. Modeled estimates of net ecosystem production (NEP) suggest that a simultaneous reduction in heterotrophic respiration increased the carbon sink for this forest. This has important implications for forest management, such as thinning where the objectives are to increase forest resilience to fire and drought, but may decrease NEP.

  6. Influence of feedstock chemical composition on product formation and characteristics derived from the hydrothermal carbonization of mixed feedstocks.

    Science.gov (United States)

    Lu, Xiaowei; Berge, Nicole D

    2014-08-01

    As the exploration of the carbonization of mixed feedstocks continues, there is a distinct need to understand how feedstock chemical composition and structural complexity influence the composition of generated products. Laboratory experiments were conducted to evaluate the carbonization of pure compounds, mixtures of the pure compounds, and complex feedstocks comprised of the pure compounds (e.g., paper, wood). Results indicate that feedstock properties do influence carbonization product properties. Carbonization product characteristics were predicted using results from the carbonization of the pure compounds and indicate that recovered solids energy contents are more accurately predicted than solid yields and the carbon mass in each phase, while predictions associated with solids surface functional groups are more difficult to predict using this linear approach. To more accurately predict carbonization products, it may be necessary to account for feedstock structure and/or additional feedstock properties. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Impact of Sundarban mangrove biosphere on the carbon dioxide and methane mixing ratios at the NE Coast of Bay of Bengal, India

    International Nuclear Information System (INIS)

    Mukhopadhyay, S.K.; Biswas, H.; De, T.K.; Jana, T.K.; Sen, B.K.; Sen, S.

    2002-01-01

    Diurnal and seasonal variations in carbon dioxide and methane fluxes between Sundarban biosphere and atmosphere were measured using micrometeorological method during 1998-2000. Study of the diurnal variation of micrometeorological conditions in the atmosphere was found to be necessary to determine the duration of neutral stability when flux estimation was reliable. Neutral stability of the atmosphere occurred in the limited micrometeorological conditions, when friction velocity ranged between 0.360 and 0.383ms -1 . The value of drag coefficient (1.62-20.6) x 10 3 obtained at variable wind speed could be deemed specific for this particular surface. 58.2% drop of carbon dioxide and 63.4% drop of methane in the atmosphere at 1m height were observed during day time, between dawn and early evening. Diurnal variations in methane and carbon dioxide mixing ratios showed a positive correlation with Richardson's number (Ri). This environment acted as a net source for carbon dioxide and methane. The mixing ratios of methane were found to vary between 1.42 and 2.07ppmv, and that of carbon dioxide, between 324.3 and 528.7ppmv during the study period. The biosphere-atmosphere flux of carbon dioxide ranged between - 3.29 and 34.4mgm -2 s -1 , and that of methane, between - 4.53 and 8.88μgm -2 s -1 . The overall annual estimate of carbon dioxide and methane fluxes from this ecosystem to atmosphere were estimated to be 694Tgyr -1 and 184Ggyr -1 , respectively. Considerable variations in mixing ratios of carbon dioxide and methane at the NE coast of Bay of Bengal were observed due to the seasonal variations of their fluxes from the biosphere to the atmosphere. The composition was inferred by fitting model prediction to measurements. (Author)

  8. Grassland carbon sequestration and emissions following cultivation in a mixed crop rotation

    DEFF Research Database (Denmark)

    Acharya, Bharat Sharma; Rasmussen, Jim; Eriksen, Jørgen

    2012-01-01

    Grasslands are potential carbon sinks to reduce unprecedented increase in atmospheric CO2. Effect of age (1–4-year-old) and management (slurry, grazing multispecies mixture) of a grass phase mixed crop rotation on carbon sequestration and emissions upon cultivation was compared with 17-year...... biomass was highest in 4-year-old grassland, but all 1–4-year-old grasslands were in between the pea field (0.81 ± 0.094 g kg−1 soil) and the 17-year-old grassland (3.17 ± 0.22 g kg−1 soil). Grazed grasslands had significantly higher root biomass than cut grasslands. There was no significant difference...... in the CO2 emissions within 1–4-year-old grasslands. Only the 17-year-old grassland showed markedly higher CO2 emissions (4.9 ± 1.1 g CO2 kg−1 soil). Differences in aboveground and root biomass did not affect CO2 emissions, and slurry application did not either. The substantial increase in root biomass...

  9. Temperature and mixing effects on electrical resistivity of carbon fiber enhanced concrete

    International Nuclear Information System (INIS)

    Chang, Christiana; Song, Gangbing; Gao, Di; Mo, Y L

    2013-01-01

    In this paper, the effect of temperature and mixing procedure on the electrical resistivity of carbon fiber enhanced concrete is investigated. Different compositions of concrete containing varying concentrations of carbon fiber into normal and self-consolidating concrete (SCC) were tested under DC electrical loading over the temperature range −10 to 20 °C. The electrical resistivity of the bulk samples was calculated and compared against temperature. It was observed that there is an inverse exponential relationship between resistivity and temperature which follows the Arrhenius relationship. The bulk resistivity decreased with increasing fiber concentration, though data from SCC indicates a saturation limit beyond which electrical resistivity begins to drop. The activation energy of the bulk electrically conductive concrete was calculated and compared. While SCC exhibited the lowest observed electrical resistance, the activation energy was similar amongst SCC and surfactant enhanced concrete, both of which were lower than fiber dispersed in normal concrete. (paper)

  10. Complex resistivity spectra in relation to multiscale pore geometry in carbonates and mixed-siliciclastic rocks

    Science.gov (United States)

    Norbisrath, Jan Henrik

    Carbonate rocks are known to have complex and heterogeneous pore structures, which result from their biogenic origin and strong affinity for diagenetic processes that change their pore structure after burial. The combination of sheer endless variations of precursor biogenic material, depositional environments, and diagenetic effects results in rocks that are interesting to study but intricate to understand. Many schemes to categorize the diversity of carbonate rocks are in use today; most are based on the macropore structure and qualitative thin-section analysis. Many studies, however, acknowledge that micropores have a significant influence on the macroscopic petrophysical rock properties, which are essential to determine reservoir quality. Micropores are, by definition, smaller than the thickness of a thin-section (four major carbonate microporosity types: (1) small intercrystalline, (2) large inter-crystalline, (3) intercement, and (4) micromoldic. Each microporosity type shows a distinct capacity to conduct electrical charge, which largely controls the magnitude and range of cementation factors (m) in rocks with such microporosity type. The BIB-SEM method is also used on a dataset of mixed carbonate-siliciclastic (mudrock) samples with high kerogen and pyrite content. Results show that the nanopore geometry here has little influence on cementation factors, and instead porosity is the main control on m in mudrocks. Cementation factors are crucial for estimates of oil-in-place and water saturation in a wireline application, and a slight change of (assumed) cementation factor can change the interpreter's evaluation from dry hole to discovery. Therefore, accurate determination of cementation factors is a critical task in formation evaluation, similar to accurate estimates of permeability. To achieve this goal, this dissertation utilizes a new approach of using complex resistivity spectra (CRS) to assess the pore geometry and its resulting electrical and fluid flow

  11. Apparatus for producing carbon-coated nanoparticles and carbon nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Perry, W. Lee; Weigle, John C.; Phillips, Jonathan

    2015-10-20

    An apparatus for producing carbon-coated nano- or micron-scale particles comprising a container for entraining particles in an aerosol gas, providing an inlet for carbon-containing gas, providing an inlet for plasma gas, a proximate torch for mixing the aerosol gas, the carbon-containing gas, and the plasma gas, bombarding the mixed gases with microwaves, and providing a collection device for gathering the resulting carbon-coated nano- or micron-scale particles. Also disclosed is a method and apparatus for making hollow carbon nano- or micro-scale spheres.

  12. A modified Wyllie equation for the relationship between porosity and sonic velocity of mixed sediments and carbonates from the Caribbean Sea

    DEFF Research Database (Denmark)

    Lind, Ida

    1997-01-01

    Continuous drill cores from the Caribbean Sea of up to 1 km thick mixed sediments and carbonates were recovered by Ocean Drilling Program Leg 165. The sediments range in porosity from 10% to 80% and in carbonate content from 20% to 95%. Unconfined P-wave velocities from this material were measured...

  13. A conceptual framework to quantify the influence of convective boundary layer development on carbon dioxide mixing ratios

    NARCIS (Netherlands)

    Pino, D.; Vilà-Guerau de Arellano, J.; Peters, W.; Schröter, J.; van Heerwaarden, C. C.; Krol, M. C.

    2012-01-01

    Interpretation of observed diurnal carbon dioxide (CO2) mixing ratios near the surface requires knowledge of the local dynamics of the planetary boundary layer. In this paper, we study the relationship between the boundary layer dynamics and the CO2 budget in convective conditions through a newly

  14. Synthesis of Mixed Carbonates via a Three-Component Coupling of Alcohols, CO2, and Alkyl Halides in the Presence of K2CO3 and Tetrabutylammonium Iodide

    OpenAIRE

    Yu-Mei Shen; Min Shi

    2002-01-01

    Various mixed carbonates can be conveniently prepared in good yields using the corresponding alcohols, alkyl halides under CO2 atmosphere in the presence of potassium carbonate or sodium carbonate and tetrabutylammonium iodide.

  15. Research on Bifurcation and Chaos in a Dynamic Mixed Game System with Oligopolies Under Carbon Emission Constraint

    Science.gov (United States)

    Ma, Junhai; Yang, Wenhui; Lou, Wandong

    This paper establishes an oligopolistic game model under the carbon emission reduction constraint and investigates its complex characteristics like bifurcation and chaos. Two oligopolistic manufacturers comprise three mixed game models, aiming to explore the variation in the status of operating system as per the upgrading of benchmark reward-penalty mechanism. Firstly, we set up these basic models that are respectively distinguished with carbon emission quantity and study these models using different game methods. Then, we concentrate on one typical game model to further study the dynamic complexity of variations in the system status, through 2D bifurcation diagrams and 4D parameter adjustment features based on the bounded rationality scheme for price, and the adaptive scheme for carbon emission. The results show that the carbon emission constraint has significant influence on the status variation of two-oligopolistic game operating systems no matter whether it is stable or chaotic. Besides, the new carbon emission regulation meets government supervision target and achieves the goal of being environment friendly by motivating the system to operate with lower carbon emission.

  16. Synthesis of Mixed Carbonates via a Three-Component Coupling of Alcohols, CO2, and Alkyl Halides in the Presence of K2CO3 and Tetrabutylammonium Iodide

    Directory of Open Access Journals (Sweden)

    Yu-Mei Shen

    2002-04-01

    Full Text Available Various mixed carbonates can be conveniently prepared in good yields using the corresponding alcohols, alkyl halides under CO2 atmosphere in the presence of potassium carbonate or sodium carbonate and tetrabutylammonium iodide.

  17. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Science.gov (United States)

    Healy, R. M.; Sciare, J.; Poulain, L.; Kamili, K.; Merkel, M.; Müller, T.; Wiedensohler, A.; Eckhardt, S.; Stohl, A.; Sarda-Estève, R.; McGillicuddy, E.; O'Connor, I. P.; Sodeau, J. R.; Wenger, J. C.

    2012-02-01

    An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS) data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150-1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and Multi-Angle Absorption Photometer (MAAP) mass concentration measurements of organic carbon (OC), inorganic ions and black carbon (BC) (R2 = 0.91). Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC) particles into four classes: (i) EC attributed to biomass burning (ECbiomass), (ii) EC attributed to traffic (ECtraffic), (iii) EC internally mixed with OC and ammonium sulfate (ECOCSOx), and (iv) EC internally mixed with OC and ammonium nitrate (ECOCNOx). Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65-0.68 respectively, n = 552). The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568). Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data

  18. Sequence stratigraphy in a mixed carbonate-silicilastic depositional system (Middle Miocene; Styrian Basin, Austria)

    Science.gov (United States)

    Friebe, J. Georg

    1993-07-01

    The mixed carbonate-siliciclastic Weißenegg (Allo-) Formation records three depositional sequences corresponding approximately to the TB 2.3, TB 2.4 and TB 2.5 global cycles. Sea-level fluctuations were of the order of at least 30 m. Siliciclastic lowstand systems tracts comprise lignite deposits, reworked basement and tidal siltstones (above a tectonically enhanced sequence boundary) as well as coastal sand bars. Coastal sands of the transgressive systems tract contain distinct layers of well cemented nodules. They are interpreted as the first stage in hardground formation and record superimposed minor sea-level fluctuations. Coral patch reefs and rhodolith platforms developed during transgressive phases and were subsequently drowned and/or suffocated by siliciclastics during early highstand. Shallowing upwards siliciclastic parasequences, each terminated by a bank of rhodolith limestone, form the (late) highstand systems tract. The limestone beds record superimposed fourth-order transgressive pulses. Occasionally a carbonate highstand wedge developed. Lowstand carbonate shedding occurred where the top of a platform which suffered incipient drowning during highstand was near sealevel again during the following lowstand. Late highstand delta progradation is common.

  19. Mechanical performance of styrene-butadiene-rubber filled with carbon nanoparticles prepared by mechanical mixing

    Energy Technology Data Exchange (ETDEWEB)

    Saatchi, M.M. [Department of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11155-9465, Tehran (Iran, Islamic Republic of); Shojaei, A., E-mail: akbar.shojaei@sharif.edu [Department of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11155-9465, Tehran (Iran, Islamic Republic of)

    2011-09-15

    Highlights: {yields} We compare influence of carbon blacks and carbon nanotube on properties of SBR. {yields} We model mechanical behavior of SBR nanocomposites by the micromechanical model. {yields} Mechanical properties of carbon black/SBR is greatly dominated by bound rubber. {yields} Mechanical properties of SBR/nanotube is governed by big aspect ratio of nanotube. - Abstract: Reinforcement of styrene-butadiene-rubber (SBR) was investigated using two different carbon blacks (CBs) with similar particle sizes, including highly structured CB and conventional CB, as well as multi-walled carbon nanotube (MWCNT) prepared by mechanical mixing. The attempts were made to examine reinforcing mechanism of these two different classes of carbon nanoparticles. Scanning electron microscopy and electrical conductivity measurement were used to investigate morphology. Tensile, cyclic tensile and stress relaxation analyses were performed. A modified Halpin-Tsai model based on the concept of an equivalent composite particle, consisting of rubber bound, occluded rubber and nanoparticle, was proposed. It was found that properties of CB filled SBR are significantly dominated by rubber shell and occluded rubber in which molecular mobility is strictly restricted. At low strains, these rubber constituents can contribute in hydrodynamic effects, leading to higher elastic modulus. However, at higher strains, they contribute in stress hardening resulting in higher elongation at break and higher tensile strength. These elastomeric regions can also influence stress relaxation behaviors of CB filled rubber. For SBR/MWCNT, the extremely great inherent mechanical properties of nanotube along with its big aspect ratio were postulated to be responsible for the reinforcement while their interfacial interaction was not so efficient.

  20. Utilization of poly(methyl methacrylate – carbon nanotube and polystyrene – carbon nanotube in situ polymerized composites as masterbatches for melt mixing

    Directory of Open Access Journals (Sweden)

    M. Lahelin

    2012-10-01

    Full Text Available Carbon nanotubes (CNTs were melt mixed directly or by using an in situ polymerized masterbatch into a matrix polymer, polystyrene (PS or poly(methyl methacrylate (PMMA. The mechanical properties of the composites were mostly determined by the amount of CNTs, and not by the use of directly melt mixed CNTs or the use of the masterbatch. In contrast, the electrical resistivity of the composites was dependent on the manner in which the CNTs were added to the matrix polymer. When there was increased interfacial adhesion between the components, as for PS and the CNTs, the use of directly melt mixed CNTs gave better resistivity results. Without strong interactions between the CNTs and the matrix, as with PMMA and CNTs, the use of a tailored masterbatch had a significant effect on properties of the final composites. The molecular weight and viscosity of masterbatches can be varied and when the PMMA-masterbatch had optimized viscosity with respect to the PMMA matrix, electrical resistivity of the final composites decreased noticeably.

  1. effects of mixed of mixed of mixed alkaline earth oxides in potash

    African Journals Online (AJOL)

    eobe

    Si, P) are network formers, and that materials whose. Nigerian ... made by mixing sand (SiO2), potassium carbonates. (K2Co3) .... The edges of the glass were grounded using ..... surface energies of minerals; theoritical estimate for oxides ...

  2. Numerical modelling of the internal mixing by coagulation of black carbon particles in aircraft exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Ohlsson, S.; Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology

    1997-12-31

    When exhaust gases from an aircraft engine mix with ambient air the humidity may reach water saturation and water droplets will form on the available cloud condensation nuclei (CCN). It is still not resolved if the CCN, on which the cloud droplets form, are mainly particles present in the ambient air or particles emitted by the aircraft. It the exhaust from a jet engine the particles are believed to consist mainly of black carbon (BC) and sulfate. The aim is to study, with the help of a numerical model, how a two-component aerosol (i.e. BC and sulfate) in an exhaust trail may be transformed in terms of hygroscopicity by coagulation mixing and how this may depend on the sulfur content in the fuel. (R.P.) 15 refs.

  3. Numerical modelling of the internal mixing by coagulation of black carbon particles in aircraft exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Ohlsson, S; Stroem, J [Stockholm Univ. (Sweden). Dept. of Meteorology

    1998-12-31

    When exhaust gases from an aircraft engine mix with ambient air the humidity may reach water saturation and water droplets will form on the available cloud condensation nuclei (CCN). It is still not resolved if the CCN, on which the cloud droplets form, are mainly particles present in the ambient air or particles emitted by the aircraft. It the exhaust from a jet engine the particles are believed to consist mainly of black carbon (BC) and sulfate. The aim is to study, with the help of a numerical model, how a two-component aerosol (i.e. BC and sulfate) in an exhaust trail may be transformed in terms of hygroscopicity by coagulation mixing and how this may depend on the sulfur content in the fuel. (R.P.) 15 refs.

  4. Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

    Directory of Open Access Journals (Sweden)

    R. M. Healy

    2012-02-01

    Full Text Available An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS and Multi-Angle Absorption Photometer (MAAP mass concentration measurements of organic carbon (OC, inorganic ions and black carbon (BC (R2 = 0.91. Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC particles into four classes: (i EC attributed to biomass burning (ECbiomass, (ii EC attributed to traffic (ECtraffic, (iii EC internally mixed with OC and ammonium sulfate (ECOCSOx, and (iv EC internally mixed with OC and ammonium nitrate (ECOCNOx. Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68 respectively, n = 552. The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568. Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle

  5. Convective mixing in helium white dwarfs

    International Nuclear Information System (INIS)

    Vauclair, G.; Fontaine, G.

    1979-01-01

    The conditions under which convective mixing episodes take place between the helium envelopes and the underlying carbon layers in helium-rich white dwarfs are investigated. It is found that, for essentially any value of the initial helium content less than the maximum mass a helium convection zone can have, mixing does occur, and leads, in the vast majority of cases, to an almost pure carbon superficial composition. Mixing products that show only traces of carbon while retaining helium-dominated envelopes are possible only if the initial helium content is quite close to the maximum possible mass of the helium convection zone. In the presence of turbulence, this restriction could be relaxed, however, and the helium-rich lambda4670 stars may possibly be explained in this fashion

  6. Electrochemical performance of mixed crystallographic phase nanotubes and nanosheets of titania and titania-carbon/silver composites for lithium-ion batteries

    International Nuclear Information System (INIS)

    Das, Shyamal K.; Bhattacharyya, Aninda J.

    2011-01-01

    Highlights: → Carbon wired TiO 2 nanotubes as anode for lithium ion batteries. → Mixed phase nanotubes show higher energy and power density than titania nanosheets. → Lithium storage and phase stabilization influenced by morphology of carbon coating. - Abstract: The role of homogeneity in ex situ grown conductive coatings and dimensionality in the lithium storage properties of TiO 2 is discussed here. TiO 2 nanotube and nanosheet comprising of mixed crystallographic phases of anatase and TiO 2 (B) have been synthesized by an optimized hydrothermal method. Surface modifications of TiO 2 nanotube are realized via coating the nanotube with Ag nanoparticles and amorphous carbon. The first discharge cycle capacity (at current rate = 10 mA g -1 ) for TiO 2 nanotube and nanosheet were 355 mAh g -1 and 225 mAh g -1 , respectively. The conductive surface coating stabilized the titania crystallographic structure during lithium insertion-deinsertion processes via reduction in the accessibility of lithium ions to the trapping sites. The irreversible capacity is beneficially minimized from 110 mAh g -1 for TiO 2 nanotubes to 96 mAh g -1 and 57 mAh g -1 respectively for Ag and carbon modified TiO 2 nanotubes. The homogeneously coated amorphous carbon over TiO 2 renders better lithium battery performance than randomly distributed Ag nanoparticles coated TiO 2 due to efficient hopping of electrons.

  7. Mixed-carbon-coated LiMn_0_._4Fe_0_._6PO_4 nanopowders with excellent high rate and low temperature performances for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zou, Bang-Kun; Wang, He-Yang; Qiang, Zi-Yue; Shao, Yu; Sun, Xin; Wen, Zhao-Yin; Chen, Chun-Hua

    2016-01-01

    Graphical abstract: Ascorbic acid acts as both an antioxidant and a surfactant to form organic groups (first carbon source) on the surface of as-solvothermal products, in which the −OH (or H_2O) groups of glucose (second carbon source) are closely bonded to the surface to form a uniform adsorption layer. Uniform mixed-carbon-coated LiMn_0_._4Fe_0_._6PO_4 nanopowders are formed after calcination, which demonstrate excellent electrochemical performances. - Highlights: • Ascorbic acid acts as both an antioxidant and a first-time carbon coating source. • Reaction mechanisms of the synthesis are carefully studied. • Mixed-carbon-coated LiMn_0_._4Fe_0_._6PO_4 nanopowders process excellent high rate and low temperature performances. - Abstract: A novel solvothermal approach with ascorbic acid as both an antioxidant and a first-time carbon coating source is developed to synthesize LiMn_0_._4Fe_0_._6PO_4 nano-particles with a uniform particle size distribution around 150 nm. A calcination step for the second-time carbon coating and further crystallization is adopted following the solvothermal step. The structures and electrochemical properties of the obtained samples are studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, Fourier transformation infrared, Infrared carbon-sulfur analyzer and galvanostatic cell cycling. Ascorbic acid plays a crucial role in the formation of uniform carbon layer and nano-particles. Compared with single-carbon-coated LiMn_0_._4Fe_0_._6PO_4 without adding ascorbic acid, the mixed-carbon-coated LiMn_0_._4Fe_0_._6PO_4 shows much better electrochemical performance. It can deliver specific capacities of 154.8 and 128.5 mAh g"−"1 at 1C and 20C, respectively, at 25 °C. Even at −20 °C, its specific capacities are 106.6 and 68.8 mAh g"−"1 at 0.2C and 5C, respectively.

  8. Impact of Grain Shape and Multiple Black Carbon Internal Mixing on Snow Albedo: Parameterization and Radiative Effect Analysis

    Science.gov (United States)

    He, Cenlin; Liou, Kuo-Nan; Takano, Yoshi; Yang, Ping; Qi, Ling; Chen, Fei

    2018-01-01

    We quantify the effects of grain shape and multiple black carbon (BC)-snow internal mixing on snow albedo by explicitly resolving shape and mixing structures. Nonspherical snow grains tend to have higher albedos than spheres with the same effective sizes, while the albedo difference due to shape effects increases with grain size, with up to 0.013 and 0.055 for effective radii of 1,000 μm at visible and near-infrared bands, respectively. BC-snow internal mixing reduces snow albedo at wavelengths external mixing, internal mixing enhances snow albedo reduction by a factor of 1.2-2.0 at visible wavelengths depending on BC concentration and snow shape. The opposite effects on albedo reductions due to snow grain nonsphericity and BC-snow internal mixing point toward a careful investigation of these two factors simultaneously in climate modeling. We further develop parameterizations for snow albedo and its reduction by accounting for grain shape and BC-snow internal/external mixing. Combining the parameterizations with BC-in-snow measurements in China, North America, and the Arctic, we estimate that nonspherical snow grains reduce BC-induced albedo radiative effects by up to 50% compared with spherical grains. Moreover, BC-snow internal mixing enhances the albedo effects by up to 30% (130%) for spherical (nonspherical) grains relative to external mixing. The overall uncertainty induced by snow shape and BC-snow mixing state is about 21-32%.

  9. Mixed alcohols production from syngas

    International Nuclear Information System (INIS)

    Stevens, R.R.; Conway, M.M.

    1988-01-01

    A process is described for selectively producing mixed alcohols from synthesis gas comprising contacting a mixture of hydrogen and carbon monoxide with a catalytic amount of a catalyst containing components of (1) a catalytically active metal of molybdenum or tungsten, in free or combined form; (2) a cocatalytic metal or cobalt or nickel in free or combined form; and (3) a Fischer-Tropsch promoter of an alkali or alkaline earth series metal, in free or combined form; the components combined by dry mixing, mixing as a wet paste, wet impregnation, and then sulfided, the catalyst excluding rhodium, ruthenium and copper, at a pressure of at least about 500 psig and under conditions sufficient to form the mixed alcohols in at least 20 percent CO/sub 2/ free carbon selectivity, the mixed alcohols containing a C/sub 1/ to C/sub 2-5/ alcohol weight ratio of less than about 1:1

  10. The influence of different black carbon and sulfate mixing methods on their optical and radiative properties

    Science.gov (United States)

    Zhang, Hua; Zhou, Chen; Wang, Zhili; Zhao, Shuyun; Li, Jiangnan

    2015-08-01

    Three different internal mixing methods (Core-Shell, Maxwell-Garnett, and Bruggeman) and one external mixing method are used to study the impact of mixing methods of black carbon (BC) with sulfate aerosol on their optical properties, radiative flux, and heating rate. The optical properties of a mixture of BC and sulfate aerosol particles are considered for three typical bands. The results show that mixing methods, the volume ratio of BC to sulfate, and relative humidity have a strong influence on the optical properties of mixed aerosols. Compared to internal mixing, external mixing underestimates the particle mass absorption coefficient by 20-70% and the particle mass scattering coefficient by up to 50%, whereas it overestimates the particle single scattering albedo by 20-50% in most cases. However, the asymmetry parameter is strongly sensitive to the equivalent particle radius, but is only weakly sensitive to the different mixing methods. Of the internal methods, there is less than 2% difference in all optical properties between the Maxwell-Garnett and Bruggeman methods in all bands; however, the differences between the Core-Shell and Maxwell-Garnett/Bruggeman methods are usually larger than 15% in the ultraviolet and visible bands. A sensitivity test is conducted with the Beijing Climate Center Radiation transfer model (BCC-RAD) using a simulated BC concentration that is typical of east-central China and a sulfate volume ratio of 75%. The results show that the internal mixing methods could reduce the radiative flux more effectively because they produce a higher absorption. The annual mean instantaneous radiative force due to BC-sulfate aerosol is about -3.18 W/m2 for the external method and -6.91 W/m2 for the internal methods at the surface, and -3.03/-1.56/-1.85 W/m2 for the external/Core-Shell/(Maxwell-Garnett/Bruggeman) methods, respectively, at the tropopause.

  11. The impacts of policy mix for resolving overcapacity in heavy chemical industry and operating national carbon emission trading market in China

    International Nuclear Information System (INIS)

    Li, Wei; Lu, Can; Ding, Yi; Zhang, Yan-Wu

    2017-01-01

    Highlights: •A STIRPAT embed dynamic CGE model is utilized to evaluate the whole impact. •Economy and trade increased slightly under scenario shock. •Global carbon emission reduction rate ranges from 3.33% to 7.46%. •Carbon emission peaks in 2022, 2024, 2026 beyond simulating scenarios. •Energy intensity decreases 19.58–23.71% upon 2020 in contrast with 2015. -- Abstract: In place to reduce greenhouse gas emission efficiently and accomplish carbon emission peak destination ahead of 2030, a variety of policy-based interventions grounded in optimizing energy structure and boosting emission mitigation have been put forward to target carbon-and resource-intensive enterprises across China. Both defusing overcapacity in heavy chemical industry and constructing national carbon trading market are recently attached with a stronger significant importance. A STIRPAT (Stochastic Impacts by Regression on Population, Affluence, and Technology) embed dynamic CGE (computable general equilibrium) model is applied in this study to evaluate the simulation effects focusing on China’s economy, energy, and household lifestyle. We devise nine scenarios in terms of the two aforementioned mitigation strategies. The results indicate that, the optimal policy mix, balancing economic improvement, energy mix readjustment, and emission reduction to the maximize value, is founded to be declining the proportion of heavy chemical industry capacity with an annual average level of 3%, 1%, 1%, stipulating carbon price in 5.8 dollar/ton, 11.6 dollar/ton, 14.5 dollar/ton, and distributing annual carbon allowance as 3.5 billion ton, 7 billion ton, 9 billion ton during 2017–2020, 2021–2025, and 2026–2030 respectively.

  12. Carbon storage as affected by different site preparation techniques two years after mixed forest stand installation

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, F.; Figueiredo, T. de; Martins, A.

    2014-06-01

    Aim of study: This study aims at evaluating the impact of site preparation techniques prior to plantation on carbon storage and distribution in a young mixed stand of Pseudotsuga menziesii (PM) and Castanea sativa (CS). Area of study: The experimental field was established near Macedo de Cavaleiros, Northern Portugal, at 700 m elevation, mean annual temperature 12 degree centigrade and mean annual rainfall 678 mm. Material and methods: The experimental layout includes three replicates, where the different treatments corresponding to different tillage intensities were randomly distributed (high, moderate and slight intensity), in plots with an area of 375 m{sup 2} each. Twenty six months after forest stand installation, samples of herbaceous vegetation (0.49 m{sup 2} quadrat), forest species (8 PM and 8 CS) and mineral soil (at 0-5, 5-15, 15-30 and 30-60 cm depth) were collected in 15 randomly selected points in each treatment, processed in laboratory and analyzed for carbon by elemental carbon analyzer. Main results: The results obtained showed that: (i) more than 90% of the total carbon stored in the system is located in the soil, increasing in depth with tillage intensity; (ii) the contribution of herbaceous vegetation and related roots to the carbon storage is very low; (iii) the amount of carbon per tree is higher in CS than in PM; (iv) the global carbon storage was affected by soil tillage generally decreasing with the increase of tillage intensity. Accordingly, carbon storage capacity as affected by the application of different site preparation techniques should be a decision support tool in afforestation schemes. (Author)

  13. Stratigraphic framework of sediment-starved sand ridges on a mixed siliciclastic/carbonate inner shelf; west-central Florida

    Science.gov (United States)

    Edwards, J.H.; Harrison, S.E.; Locker, S.D.; Hine, A.C.; Twichell, D.C.

    2003-01-01

    Seismic reflection profiles and vibracores have revealed that an inner shelf, sand-ridge field has developed over the past few thousand years situated on an elevated, broad bedrock terrace. This terrace extends seaward of a major headland associated with the modern barrier-island coastline of west-central Florida. The overall geologic setting is a low-energy, sediment-starved, mixed siliciclastic/carbonate inner continental shelf supporting a thin sedimentary veneer. This veneer is arranged in a series of subparallel, shore-oblique, and to a minor extent, shore-parallel sand ridges. Seven major facies are present beneath the ridges, including a basal Neogene limestone gravel facies and a blue-green clay facies indicative of dominantly authigenic sedimentation. A major sequence boundary separates these older units from Holocene age, organic-rich mud facies (marsh), which grades upward into a muddy sand facies (lagoon or shallow open shelf/seagrass meadows). Cores reveal that the muddy shelf facies is either in sharp contact or grades upward into a shelly sand facies (ravinement or sudden termination of seagrass meadows). The shelly sand facies grades upward to a mixed siliciclastic/carbonate facies, which forms the sand ridges themselves. This mixed siliciclastic/carbonate facies differs from the sediment on the beach and shoreface, suggesting insignificant sediment exchange between the offshore ridges and the modern coastline. Additionally, the lack of early Holocene, pre-ridge facies in the troughs between the ridges suggests that the ridges themselves do not migrate laterally extensively. Radiocarbon dating has indicated that these sand ridges can form relatively quickly (???1.3 ka) on relatively low-energy inner shelves once open-marine conditions are available, and that frequent, high-energy, storm-dominated conditions are not necessarily required. We suggest that the two inner shelf depositional models presented (open-shelf vs. migrating barrier-island) may

  14. New flash mixing

    International Nuclear Information System (INIS)

    Sackmann, I.

    1980-01-01

    It was found that even for stars evolved away from the red giant branch, a new mixing of nucleo-synthesis products from the hydrogen-burning shells into surface layers was possible, from the penetration of the contaminated intershell region with the H- and He-ionization convection zones. This is due to the helium shell flash driving an immense expansion of an inner carbon pocket, namely, by a factor of 12,000 in radius, a drop in density of about 10 12 , and a cooling of inner pockets normally near 10 8 K to 23,000 K. The surface would be enriched in carbon ( 12 C), helium ( 4 He), and s-process elements, but not significantly in nitrogen ( 14 N), oxygen ( 16 O), or the isotope 13 C. This new type of mixing might provide the missing clue for FG Sagittae. Such a mixing had been suggested by the observations of FG Sagittae, but had been unexplainable by theory up to now

  15. Study of the Bioremediation of Atrazine under Variable Carbon and Nitrogen Sources by Mixed Bacterial Consortium Isolated from Corn Field Soil in Fars Province of Iran

    Science.gov (United States)

    Nasseri, Simin; Hashemi, Hassan

    2013-01-01

    Atrazine herbicide that is widely used in corn production is frequently detected in water resources. The main objectives of this research were focused on assessing the effects of carbon and nitrogen sources on atrazine biodegradation by mixed bacterial consortium and by evaluating the feasibility of using mixed bacterial consortium in soil culture. Shiraz corn field soil with a long history of atrazine application has been explored for their potential of atrazine biodegradation. The influence of different carbon compounds and the effect of nitrogen sources and a different pH (5.5–8.5) on atrazine removal efficiency by mixed bacterial consortium in liquid culture were investigated. Sodium citrate and sucrose had the highest atrazine biodegradation rate (87.22%) among different carbon sources. Atrazine biodegradation rate decreased more quickly by the addition of urea (26.76%) compared to ammonium nitrate. Based on the data obtained in this study, pH of 7.0 is optimum for atrazine biodegradation. After 30 days of incubation, the percent of atrazine reduction rates were significantly enhanced in the inoculated soils (60.5%) as compared to uninoculated control soils (12%) at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with mixed bacterial consortium may enhance the rate of atrazine degradation in a highly polluted soil. PMID:23533452

  16. Amine–mixed oxide hybrid materials for carbon dioxide adsorption from CO2/H2 mixture

    Science.gov (United States)

    Ravi, Navin; Aishah Anuar, Siti; Yusuf, Nur Yusra Mt; Isahak, Wan Nor Roslam Wan; Shahbudin Masdar, Mohd

    2018-05-01

    Bio-hydrogen mainly contains hydrogen and high level of carbon dioxide (CO2). High concentration of CO2 lead to a limitation especially in fuel cell application. In this study, the amine-mixed oxide hybrid materials for CO2 separation from bio-hydrogen model (50% CO2:50% H2) have been studied. Fourier-transform infrared spectroscopy (FTIR) and x-ray diffraction (XRD) characterizations showed that the amine–mixed oxide hybrid materials successfully adsorbed CO2 physically with no chemical adsorption evidence. The dry gas of CO2/H2 mixture adsorbed physically on amine–CuO–MgO hybrid material. No carbonates were detected after several times of adsorption, which indicated the good recyclability of adsorbents. The adsorbent system of diethanolamine (DEA)/15% CuO–75% MgO showed the highest CO2 adsorption capacity of 21.2 wt% due to the presence of polar substance on MgO surface, which can adsorb CO2 at ambient condition. The alcohol group of DEA can enhance the CO2 solubility on the adsorbent surface. In the 20% CuO–50% MgO adsorbent system, DEA as amine type showed a high CO2 adsorption of 19.4 wt%. The 10% amine loading system showed that the DEA adsorption system provided high CO2 adsorption. The BET analysis confirmed that a high amine loading contributed to the decrease in CO2 adsorption due to the low surface area of the adsorbent system.

  17. Energy footprint and carbon emission reduction using off-the-grid solar-powered mixing for lagoon treatment.

    Science.gov (United States)

    Jiang, Yuyuan; Bebee, Brian; Mendoza, Alvaro; Robinson, Alice K; Zhang, Xiaying; Rosso, Diego

    2018-01-01

    Mixing is the driver for the energy footprint of water resource recovery in lagoons. With the availability of solar-powered equipment, one potential measure to decrease the environmental impacts of treatment is to transition to an off-the-grid treatment. We studied the comparative scenarios of an existing grid-powered mixer and a solar-powered mixer. Testing was conducted to monitor the water quality, and to guarantee that the effluent concentrations were maintained equally between the two scenarios. Meanwhile, the energy consumption was recorded with the electrical energy monitor by the wastewater treatment utility, and the carbon emission changes were calculated using the emission intensity of the power utility. The results show that after the replacement, both energy usage and energy costs were significantly reduced, with the energy usage having decreased by 70% and its cost by 47%. Additionally, carbon-equivalent emission from electricity importation dropped by 64%, with an effect on the overall carbon emissions (i.e., including all other contributions from the process) decreasing from 3.8% to 1.5%. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Super-hierarchical porous carbons derived from mixed biomass wastes by a stepwise removal strategy for high-performance supercapacitors

    Science.gov (United States)

    Peng, Lin; Liang, Yeru; Dong, Hanwu; Hu, Hang; Zhao, Xiao; Cai, Yijing; Xiao, Yong; Liu, Yingliang; Zheng, Mingtao

    2018-02-01

    The synthesis and energy storage application of hierarchical porous carbons with size ranging from nano-to micrometres has attracted considerable attention all over the world. Exploring eco-friendly and reliable synthesis of hierarchical porous carbons for supercapacitors with high energy density and high power is still of ongoing challenge. In this work, we report the design and synthesis of super-hierarchical porous carbons with highly developed porosity by a stepwise removal strategy for high-rate supercapacitors. The mixed biomass wastes of coconut shell and sewage sludge are employed as raw material. The as-prepared super-hierarchical porous carbons present high surface areas (3003 m2 g-1), large pore volume (2.04 cm3 g-1), appropriate porosity, and outstanding electrochemical performance. The dependence of electrochemical performance on structural, textural, and functional properties of carbons engineered by various synthesis strategies is investigated in detail. Moreover, the as-assembled symmetrical supercapacitor exhibits high energy density of 25.4 Wh kg-1 at a power density of 225 W kg-1 and retains 20.7 Wh kg-1 even at a very high power of 9000 W kg-1. This work provides an environmentally benign strategy and new insights to efficiently regulate the porosity of hierarchical porous carbons derived from biomass wastes for energy storage applications.

  19. The influence of different black carbon and sulfate mixing methods on their optical and radiative properties

    International Nuclear Information System (INIS)

    Zhang, Hua; Zhou, Chen; Wang, Zhili; Zhao, Shuyun; Li, Jiangnan

    2015-01-01

    Three different internal mixing methods (Core–Shell, Maxwell-Garnett, and Bruggeman) and one external mixing method are used to study the impact of mixing methods of black carbon (BC) with sulfate aerosol on their optical properties, radiative flux, and heating rate. The optical properties of a mixture of BC and sulfate aerosol particles are considered for three typical bands. The results show that mixing methods, the volume ratio of BC to sulfate, and relative humidity have a strong influence on the optical properties of mixed aerosols. Compared to internal mixing, external mixing underestimates the particle mass absorption coefficient by 20–70% and the particle mass scattering coefficient by up to 50%, whereas it overestimates the particle single scattering albedo by 20–50% in most cases. However, the asymmetry parameter is strongly sensitive to the equivalent particle radius, but is only weakly sensitive to the different mixing methods. Of the internal methods, there is less than 2% difference in all optical properties between the Maxwell-Garnett and Bruggeman methods in all bands; however, the differences between the Core–Shell and Maxwell-Garnett/Bruggeman methods are usually larger than 15% in the ultraviolet and visible bands. A sensitivity test is conducted with the Beijing Climate Center Radiation transfer model (BCC-RAD) using a simulated BC concentration that is typical of east-central China and a sulfate volume ratio of 75%. The results show that the internal mixing methods could reduce the radiative flux more effectively because they produce a higher absorption. The annual mean instantaneous radiative force due to BC–sulfate aerosol is about –3.18 W/m 2 for the external method and –6.91 W/m 2 for the internal methods at the surface, and –3.03/–1.56/–1.85 W/m 2 for the external/Core–Shell/(Maxwell-Garnett/Bruggeman) methods, respectively, at the tropopause. - Highlights: • The aerosol optical properties with different mixing

  20. Investigation of plasma interaction with carbon based and mixed materials related to next-generation fusion devices

    International Nuclear Information System (INIS)

    Guseva, M.I.; Martynenko, Yu.V.; Korshunov, S.N.

    2003-01-01

    Carbon-carbon composites, tungsten and beryllium are considered at present as candidate-materials for International Thermonuclear Experimental Reactor (ITER). The presence of various materials, as the divertor and the first wall components, will unavoidably result in the formation of mixed layers on the surfaces of plasma facing components. In this review, processes of plasma interaction with these materials and layers formed by mixing of the materials are considered. Mixed W-Be and W-C layers were prepared by deposition of two species atoms upon a substrate under simultaneous sputtering of two targets by 20 keV Ar + -ions. The thickness of the deposited mixed layers was 100-500 nm. The most important processes investigated here are: a) erosion at threshold energies and at various temperatures, b) erosion at plasma disruption, c) surface modification at normal operation regime and disruption, d) the influence of the surface modification on material erosion, e) erosion product formation at plasma disruption (dust creation), f) hydrogen isotopes retention in materials. An experimental method of determination of sputtering yield under ion bombardment in the near-threshold energy range has been developed. The method is based on the use of special regimes of field ion microscopic analysis. The method has been used for measurement of the sputtering yield of C-C composite, technically pure tungsten, tungsten oxide and mixed W-C layer on the tungsten by deuterium ions. The energy dependences of the sputtering yield of those materials by deuterium ions at energies ranging from 10 to 500 eV was investigated. Temperature dependences of pure and B-doped C-C composites erosion by deuterium ions were investigated. Material erosion was studied in a steady state plasma at the LENTA facility with parameters close to those expected at normal operation of ITER, and in the MKT plasma accelerator simulating plasma disruption. Surface modifications of graphite materials and tungsten

  1. Mixed Matrix Carbon Molecular Sieve and Alumina (CMS-Al2O3) Membranes.

    Science.gov (United States)

    Song, Yingjun; Wang, David K; Birkett, Greg; Martens, Wayde; Duke, Mikel C; Smart, Simon; Diniz da Costa, João C

    2016-07-29

    This work shows mixed matrix inorganic membranes prepared by the vacuum-assisted impregnation method, where phenolic resin precursors filled the pore of α-alumina substrates. Upon carbonisation, the phenolic resin decomposed into several fragments derived from the backbone of the resin matrix. The final stages of decomposition (>650 °C) led to a formation of carbon molecular sieve (CMS) structures, reaching the lowest average pore sizes of ~5 Å at carbonisation temperatures of 700 °C. The combination of vacuum-assisted impregnation and carbonisation led to the formation of mixed matrix of CMS and α-alumina particles (CMS-Al2O3) in a single membrane. These membranes were tested for pervaporative desalination and gave very high water fluxes of up to 25 kg m(-2) h(-1) for seawater (NaCl 3.5 wt%) at 75 °C. Salt rejection was also very high varying between 93-99% depending on temperature and feed salt concentration. Interestingly, the water fluxes remained almost constant and were not affected as feed salt concentration increased from 0.3, 1 and 3.5 wt%.

  2. Thermal stability and oxidizing properties of mixed alkaline earth-alkali molten carbonates: A focus on the lithium-sodium carbonate eutectic system with magnesium additions

    International Nuclear Information System (INIS)

    Frangini, Stefano; Scaccia, Silvera

    2013-01-01

    Highlights: • TG/DSC analysis was conducted on magnesium-containing eutectic Li/Na eutectic carbonates. • Magnesium influence on the oxygen solubility properties of carbonate was also experimentally determined at 600 °C and 650 °C. • A reproducible partial decarbonation process in premelting region caused formation of magnesium oxycarbonate-like phases. • The acidobase buffering action of magnesium oxycarbonate species could explain the high basic/oxidizing properties of such carbonate melts. • A general correlation between thermal instability in premelting region and basic/oxidizing melt properties was established. - Abstract: A comparative study on thermal behavior and oxygen solubility properties of eutectic 52/48 lithium/sodium carbonate salt containing minor additions of magnesium up to 10 mol% has been made in order to determine whether a general correlation between these two properties can be found or not. Consecutive TG/DSC heating/cooling thermal cycles carried out under alternating CO 2 and N 2 gas flows allowed to assign thermal events observed in the premelting region to a partial decarbonation process of the magnesium-alkali mixed carbonates. The observed decarbonation process at 460 °C is believed to come from initial stage of thermal decomposition of magnesium carbonate resulting in the metastable formation of magnesium oxycarbonate-like phases MgO·2MgCO 3 , in a similar manner as previously reported for lanthanum. Reversible formation and decomposition of the magnesium carbonate phase has been observed under a CO 2 gas atmosphere. The intensity of the decomposition process shows a maximum for a 3 mol% MgO addition that gives also the highest oxygen solubility, suggesting therefore that instability thermal analysis in the premelting region can be considered as providing an effective measure of the basicity/oxidizing properties of alkali carbonate melts with magnesium or, in more general terms, with cations that are strong modifiers of

  3. Removals of aqueous sulfur dioxide and hydrogen sulfide using CeO2-NiAl-LDHs coating activated carbon and its mix with carbon nano-tubes

    KAUST Repository

    Li, Jing; Chen, Fangping; Jin, Guanping; Feng, Xiaoshuang; Li, Xiaoxuan

    2015-01-01

    Ce-doped NiAl/layered double hydroxide was coated at activated carbon by urea hydrolysis method (CeO2-NiAl-LDHs/AC) in one pot, which was characterized by X-ray diffraction, infrared spectra, field emission scanning electron microscope and electrochemical techniques. CeO2-NiAl-LDHs/AC shows good uptake for aqueous sulfur dioxide (483.09mg/g) and hydrogen sulfide (181.15mg/g), respectively at 25°C. Meanwhile, the electrochemical removals of aqueous sulfur dioxide and hydrogen sulfide were respectively investigated at the mix of CeO2-NiAl-LDHs/AC and carbon nano-tubes modified homed paraffin-impregnated electrode. Both sulfur dioxide and hydrogen sulfide could be effectively oxidized to sulfuric acid at 1.0V in alkaline aqueous solution. © 2015 Elsevier B.V.

  4. Removals of aqueous sulfur dioxide and hydrogen sulfide using CeO2-NiAl-LDHs coating activated carbon and its mix with carbon nano-tubes

    KAUST Repository

    Li, Jing

    2015-07-01

    Ce-doped NiAl/layered double hydroxide was coated at activated carbon by urea hydrolysis method (CeO2-NiAl-LDHs/AC) in one pot, which was characterized by X-ray diffraction, infrared spectra, field emission scanning electron microscope and electrochemical techniques. CeO2-NiAl-LDHs/AC shows good uptake for aqueous sulfur dioxide (483.09mg/g) and hydrogen sulfide (181.15mg/g), respectively at 25°C. Meanwhile, the electrochemical removals of aqueous sulfur dioxide and hydrogen sulfide were respectively investigated at the mix of CeO2-NiAl-LDHs/AC and carbon nano-tubes modified homed paraffin-impregnated electrode. Both sulfur dioxide and hydrogen sulfide could be effectively oxidized to sulfuric acid at 1.0V in alkaline aqueous solution. © 2015 Elsevier B.V.

  5. Study of the Bioremediation of Atrazine under Variable Carbon and Nitrogen Sources by Mixed Bacterial Consortium Isolated from Corn Field Soil in Fars Province of Iran

    Directory of Open Access Journals (Sweden)

    Mansooreh Dehghani

    2013-01-01

    Full Text Available Atrazine herbicide that is widely used in corn production is frequently detected in water resources. The main objectives of this research were focused on assessing the effects of carbon and nitrogen sources on atrazine biodegradation by mixed bacterial consortium and by evaluating the feasibility of using mixed bacterial consortium in soil culture. Shiraz corn field soil with a long history of atrazine application has been explored for their potential of atrazine biodegradation. The influence of different carbon compounds and the effect of nitrogen sources and a different pH (5.5–8.5 on atrazine removal efficiency by mixed bacterial consortium in liquid culture were investigated. Sodium citrate and sucrose had the highest atrazine biodegradation rate (87.22% among different carbon sources. Atrazine biodegradation rate decreased more quickly by the addition of urea (26.76% compared to ammonium nitrate. Based on the data obtained in this study, pH of 7.0 is optimum for atrazine biodegradation. After 30 days of incubation, the percent of atrazine reduction rates were significantly enhanced in the inoculated soils (60.5% as compared to uninoculated control soils (12% at the soil moisture content of 25%. In conclusion, bioaugmentation of soil with mixed bacterial consortium may enhance the rate of atrazine degradation in a highly polluted soil.

  6. Parallel measurements of organic and elemental carbon dry (PM1, PM2.5) and wet (rain, snow, mixed) deposition into the Baltic Sea.

    Science.gov (United States)

    Witkowska, Agnieszka; Lewandowska, Anita; Falkowska, Lucyna M

    2016-03-15

    Parallel studies on organic and elemental carbon in PM1 and PM2.5 aerosols and in wet deposition in various forms of its occurrence were conducted in the urbanised coastal zone of the Baltic Sea. The carbon load introduced into the sea water was mainly affected by the form of precipitation. Dry deposition load of carbon was on average a few orders of magnitude smaller than wet deposition. The suspended organic carbon was more effectively removed from the air with rain than snow, while an inverse relationship was found for elemental carbon. However the highest flux of water insoluble organic carbon was recorded in precipitation of a mixed nature. The atmospheric cleaning of highly dissolved organic carbon was observed to be the most effective on the first day of precipitation, while the hydrophobic elemental carbon was removed more efficiently when the precipitation lasted longer than a day. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Carbon dioxide dangers demonstration model

    Science.gov (United States)

    Venezky, Dina; Wessells, Stephen

    2010-01-01

    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.

  8. Carbon dioxide capture from reforming gases using acetic acid-mixed chemical absorbents

    Energy Technology Data Exchange (ETDEWEB)

    Rahmanian, Amin; Zaini, Muhammad Abbas ahmad; Abdullah, Tuan Amran Tuan [Faculty of Chemical Engineering, Universiti Teknologi Malaysia, Johor Bahru (Malaysia)

    2015-07-15

    Carbon dioxide (CO{sub 2}) is a major problem in the production of natural gas as it may contribute to the operational problems such as foaming, corrosion, high solution viscosity, and fouling, thereby decreasing the plant life. The presence of acid gas in natural gas reforming may also result in the increase of transported gas volume and the decrease of heating value. Absorption using aqueous solutions of alkanolamines has been a preferred approach in current industry for CO{sub 2} removal. Concentration of ammonia and DEA affects the CO{sub 2} removal; increasing the absorbents concentration increases the CO{sub 2} removal. On molar basis, DEA shows a greater CO{sub 2} absorption than ammonia. Acetic acid-mixed absorbents display a lower CO{sub 2} removal than the nonmixed ones. Decrease in solubility due to the decrease in solution pH has resulted in a lower CO{sub 2} absorption by acetic acid-mixed absorbents. Liquid flow rate offers only small influence on the absorption of CO{sub 2}, while decreasing the gas flow rate increases the CO{sub 2} removal. On the operational point of view, blend of ammonia and DEA absorbent would be beneficial for CO{sub 2} removal from reforming gases as it could partly solve the problems associated with regeneration and corrosion.

  9. Carbon dioxide selective adsorption within a highly stable mixed-ligand Zeolitic Imidazolate Framework

    KAUST Repository

    Huang, Lin

    2014-08-01

    A new mixed-ligand Zeolitic Imidazolate Framework Zn4(2-mbIm) 3(bIm)5·4H2O (named JUC-160, 2-mbIm = 2-methylbenzimidazole, bIm = benzimidazole and JUC = Jilin University China) was synthesized with a solvothermal reaction of Zn(NO3) 2·6H2O, bIm and 2-mbIm in DMF solution at 180 °C. Topological analysis indicated that JUC-160 has a zeolite GIS (gismondine) topology. Study of the gas adsorption and thermal and chemical stability of JUC-160 demonstrated its selective adsorption property for carbon dioxide, high thermal stability, and remarkable chemical resistance to boiling alkaline water and organic solvent for up to one week. © 2014 Elsevier B.V.

  10. Mix for production of heavy concretes

    International Nuclear Information System (INIS)

    Skvara, F.; Halen, S.; Kolar, K.; Novotny, J.; Zadak, Z.; Zezulka, J.

    1981-01-01

    The mix consists of 76 to 99.79 wt.% of cement clay of a specific area of 150 to 3000 m 2 /kg, of heavy aggregate (in a ratio of 1 part of cement clay to more than 1 part of the heavy aggregate) and of 0.1 to 8 wt.% of lignosulphonic acid salt. The mix also contains 0.1 to 8 wt.% of boric acid, 0.01 to 8 wt.% of a carbonate or a hydrogen carbonate of an alkali metal. (H.S.)

  11. First-principles study on electron transport properties of carbon-silicon mixed chains

    Science.gov (United States)

    Hu, Wei; Zhou, Qinghua; Liang, Yan; Liu, Wenhua; Wang, Tao; Wan, Haiqing

    2018-03-01

    In this paper, the transport properties of carbon-silicon mixed chains are studied by using the first-principles. We studied five atomic chain models. In these studies, we found that the equilibrium conductances of atomic chains appear to oscillate, the maximum conductance and the minimum conductance are more than twice the difference. Their I-V curves are linear and show the behavior of metal resistance, M5 system and M2 system current ratio is the largest in 0.9 V, which is 3.3, showing a good molecular switch behavior. In the case of bias, while the bias voltage increases, the transmission peaks move from the Fermi level. The resonance transmission peak height is reduced near the Fermi level. In the higher energy range, a large resonance transmission peak reappears, there is still no energy cut-off range.

  12. Laboratory scale characterizations of the mixing zone for reactive transport in a carbonate system

    International Nuclear Information System (INIS)

    Kassab, M.F.

    2012-01-01

    We have performed laboratory-scale percolation experiments combining hydrodynamic and geochemical reaction processes in a unique setup to study the evolution of permeability induced by dissolution reactions in a natural Carbonate system. First, the key parameters controlling Calcite dissolution due to mixing of two end member solutions representing fresh and sea waters are assessed through typical geochemical modeling. Both solutions are at equilibrium with Calcite and are associated with different values of partial pressure of CO 2 and salinity. Mixing of the two selected end members provides a sub saturated solution with low and moderate ionic strength, high pCO 2 , and high salinity. Modeling results reveal that the maximum sub saturation is expected to occur for mixing ratios of about 15%. The expected dissolved Calcite until equilibrium attains its maximum at a mixing ratio of about 45%. Experimental results indicate that the calcite dissolution rate at a 15% mixing ratio is higher than that observed at 45% mixing ratio. The outlet solution from the sample reactor is always under saturated with respect to Calcite. Permeability of the tested sample displays a rapid decrease during the beginning of injection. It then shows a stable behavior until the end of percolation when the porosity of the sample increases due to dissolution. To understand permeability and porosity evolution obtained from the mixing experiments we perform dissolution experiments under different dissolution regimes by injection of deionized water (DW) and/or DW enriched with CO 2 . It is observed that permeability decreases when DW is injected whereas it increases following injection of DW enriched with CO 2 . The observed global dissolution rate of Calcite is larger for the experiments with DW enriched with CO 2 than for those performed with DW. The observed permeability reduction is due to the clogging of connected pore caused by migration of micro particles detaching from the host porous

  13. Water soluble organic carbon in aerosols (PM1, PM2.5, PM10) and various precipitation forms (rain, snow, mixed) over the southern Baltic Sea station.

    Science.gov (United States)

    Witkowska, Agnieszka; Lewandowska, Anita U

    2016-12-15

    In the urbanized coastal zone of the Southern Baltic, complex measurements of water soluble organic carbon (WSOC) were conducted between 2012 and 2015, involving atmospheric precipitation in its various forms (rain, snow, mixed) and PM1, PM2.5 and PM10 aerosols. WSOC constituted about 60% of the organic carbon mass in aerosols of various sizes. The average concentration of WSOC was equal to 2.6μg∙m -3 in PM1, 3.6μg∙m -3 in PM2.5 and 4.4μg∙m -3 in PM10. The lowest concentration of WSOC was noted in summer as a result of effective removal of this compound with rainfall. The highest WSOC concentrations in PM2.5 and PM10 aerosols were measured in spring, which should be associated with developing vegetation on land and in the sea. On the other hand, the highest WSOC concentrations in PM1 occurred in winter at low air temperatures and greatest atmospheric stability, when there were increased carbon emissions from fuel combustion in the communal-utility sector and from transportation. WSOC concentrations in precipitation were determined by its form. Mixed precipitation turned out to be the richest in soluble organic carbon (5.1mg·dm -3 ), while snow contained the least WSOC (1.7mg·dm -3 ). Snow and rain cleaned carbon compounds from the atmosphere more effectively when precipitation lasted longer than 24h, while in the case of mixed precipitation WSOC was removed most effectively within the first 24h. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Hanford/Rocky Flats collaboration on development of supercritical carbon dioxide extraction to treat mixed waste

    International Nuclear Information System (INIS)

    Hendrickson, D.W.; Biyani, R.K.; Brown, C.M.; Teter, W.L.

    1995-11-01

    Proposals for demonstration work under the Department of Energy's Mixed Waste Focus Area, during the 1996 through 1997 fiscal years included two applications of supercritical carbon dioxide to mixed waste pretreatment. These proposals included task RF15MW58 of Rocky Flats and task RL46MW59 of Hanford. Analysis of compatibilities in wastes and work scopes yielded an expectation of substantial collaboration between sites whereby Hanford waste streams may undergo demonstration testing at Rocky Flats, thereby eliminating the need for test facilities at Hanford. This form of collaboration is premised the continued deployment at Rocky Flats and the capability for Hanford samples to be treated at Rocky Flats. The recent creation of a thermal treatment contract for a facility near Hanford may alleviate the need to conduct organic extraction upon Rocky Flats wastes by providing a cost effective thermal treatment alternative, however, some waste streams at Hanford will continue to require organic extraction. Final site waste stream treatment locations are not within the scope of this document

  15. Hanford/Rocky Flats collaboration on development of supercritical carbon dioxide extraction to treat mixed waste

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, D.W.; Biyani, R.K. [Westinghouse Hanford Co., Richland, WA (United States); Brown, C.M.; Teter, W.L. [Kaiser-Hill Co., Golden, CO (United States)

    1995-11-01

    Proposals for demonstration work under the Department of Energy`s Mixed Waste Focus Area, during the 1996 through 1997 fiscal years included two applications of supercritical carbon dioxide to mixed waste pretreatment. These proposals included task RF15MW58 of Rocky Flats and task RL46MW59 of Hanford. Analysis of compatibilities in wastes and work scopes yielded an expectation of substantial collaboration between sites whereby Hanford waste streams may undergo demonstration testing at Rocky Flats, thereby eliminating the need for test facilities at Hanford. This form of collaboration is premised the continued deployment at Rocky Flats and the capability for Hanford samples to be treated at Rocky Flats. The recent creation of a thermal treatment contract for a facility near Hanford may alleviate the need to conduct organic extraction upon Rocky Flats wastes by providing a cost effective thermal treatment alternative, however, some waste streams at Hanford will continue to require organic extraction. Final site waste stream treatment locations are not within the scope of this document.

  16. Effect of regional grid mix, driving patterns and climate on the comparative carbon footprint of gasoline and plug-in electric vehicles in the United States

    Science.gov (United States)

    Yuksel, Tugce; Tamayao, Mili-Ann M.; Hendrickson, Chris; Azevedo, Inês M. L.; Michalek, Jeremy J.

    2016-04-01

    We compare life cycle greenhouse gas (GHG) emissions from several light-duty passenger gasoline and plug-in electric vehicles (PEVs) across US counties by accounting for regional differences due to marginal grid mix, ambient temperature, patterns of vehicle miles traveled (VMT), and driving conditions (city versus highway). We find that PEVs can have larger or smaller carbon footprints than gasoline vehicles, depending on these regional factors and the specific vehicle models being compared. The Nissan Leaf battery electric vehicle has a smaller carbon footprint than the most efficient gasoline vehicle (the Toyota Prius) in the urban counties of California, Texas and Florida, whereas the Prius has a smaller carbon footprint in the Midwest and the South. The Leaf is lower emitting than the Mazda 3 conventional gasoline vehicle in most urban counties, but the Mazda 3 is lower emitting in rural Midwest counties. The Chevrolet Volt plug-in hybrid electric vehicle has a larger carbon footprint than the Prius throughout the continental US, though the Volt has a smaller carbon footprint than the Mazda 3 in many urban counties. Regional grid mix, temperature, driving conditions, and vehicle model all have substantial implications for identifying which technology has the lowest carbon footprint, whereas regional patterns of VMT have a much smaller effect. Given the variation in relative GHG implications, it is unlikely that blunt policy instruments that favor specific technology categories can ensure emission reductions universally.

  17. Effect of regional grid mix, driving patterns and climate on the comparative carbon footprint of gasoline and plug-in electric vehicles in the United States

    International Nuclear Information System (INIS)

    Yuksel, Tugce; Michalek, Jeremy J; Tamayao, Mili-Ann M; Hendrickson, Chris; Azevedo, Inês M L

    2016-01-01

    We compare life cycle greenhouse gas (GHG) emissions from several light-duty passenger gasoline and plug-in electric vehicles (PEVs) across US counties by accounting for regional differences due to marginal grid mix, ambient temperature, patterns of vehicle miles traveled (VMT), and driving conditions (city versus highway). We find that PEVs can have larger or smaller carbon footprints than gasoline vehicles, depending on these regional factors and the specific vehicle models being compared. The Nissan Leaf battery electric vehicle has a smaller carbon footprint than the most efficient gasoline vehicle (the Toyota Prius) in the urban counties of California, Texas and Florida, whereas the Prius has a smaller carbon footprint in the Midwest and the South. The Leaf is lower emitting than the Mazda 3 conventional gasoline vehicle in most urban counties, but the Mazda 3 is lower emitting in rural Midwest counties. The Chevrolet Volt plug-in hybrid electric vehicle has a larger carbon footprint than the Prius throughout the continental US, though the Volt has a smaller carbon footprint than the Mazda 3 in many urban counties. Regional grid mix, temperature, driving conditions, and vehicle model all have substantial implications for identifying which technology has the lowest carbon footprint, whereas regional patterns of VMT have a much smaller effect. Given the variation in relative GHG implications, it is unlikely that blunt policy instruments that favor specific technology categories can ensure emission reductions universally. (letter)

  18. Investigation of bioresistant dry building mixes modified by carbon nanotubes

    OpenAIRE

    Korolev Evgeniy Valer'evich; Erofeev Vladimir Trofimovich; Suraeva Ekaterina Nikolaevna

    2015-01-01

    Dry construction mixes are today a product of high technologies. Depending on the purpose and requirements to the properties it is easy to produce dry construction mixes with different compositions and operating indicators in plant conditions using the necessary modifying additives. Cement, gypsum and other mineral binders are used in the construction mixes. Different types of cement are more heavily used in dry construction mixes. Such dry mixes are believed to be more effective materials co...

  19. Carbon fuel particles used in direct carbon conversion fuel cells

    Science.gov (United States)

    Cooper, John F.; Cherepy, Nerine

    2012-10-09

    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.

  20. Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells

    Science.gov (United States)

    Cooper, John F.; Cherepy, Nerine

    2008-10-21

    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.

  1. Methods of analyzing carbon nanostructures, methods of preparation of analytes from carbon nanostructures, and systems for analyzing carbon nanostructures

    KAUST Repository

    Da Costa, Pedro Miquel Ferreira Joaquim

    2016-09-09

    Provided herein is a method determining the concentration of impurities in a carbon material, comprising: mixing a flux and a carbon material to form a mixture, wherein the carbon material is selected from the group consisting of graphene, carbon nanotubes, fullerene, carbon onions, graphite, carbon fibers, and a combination thereof; heating the mixture using microwave energy to form fused materials; dissolution of the fused materials in an acid mixture; and measuring the concentration of one or more impurities.

  2. The seasonal cycle of the mixing layer height and its impact on black carbon concentrations in the Kathmandu Valley (Nepal)

    Science.gov (United States)

    Mues, Andrea; Rupakheti, Maheswar; Hoor, Peter; Bozem, Heiko; Münkel, Christoph; Lauer, Axel; Butler, Tim

    2016-04-01

    The properties and the vertical structure of the mixing layer as part of the planetary boundary layer are of key importance for local air quality. They have a substantial impact on the vertical dispersion of pollutants in the lower atmosphere and thus on their concentrations near the surface. In this study, ceilometer measurements taken within the framework of the SusKat project (Sustainable Atmosphere for the Kathmandu Valley) are used to investigate the mixing layer height in the Kathmandu Valley, Nepal. The applied method is based on the assumption that the aerosol concentration is nearly constant in the vertical and distinctly higher within the mixing layer than in the air above. Thus, the height with the steepest gradient within the ceilometer backscatter profile marks the top of the mixing layer. Ceilometer and black carbon (BC) measurements conducted from March 2013 through February 2014 provide a unique and important dataset for the analysis of the meteorological and air quality conditions in the Kathmandu Valley. In this study the mean diurnal cycle of the mixing layer height in the Kathmandu Valley for each season (pre-monsoon, monsoon, post-monsoon and winter season) and its dependency on the meteorological situation is investigated. In addition, the impact of the mixing layer height on the BC concentration is analyzed and compared to the relevance of other important processes such as emissions, horizontal advection and deposition. In all seasons the diurnal cycle is typically characterized by low mixing heights during the night, gradually increasing after sun rise reaching to maximum values in the afternoon before decreasing again. Seasonal differences can be seen particularly in the height of the mixing layer, e.g. from on average 153/1200 m (pre-monsoon) to 241/755 m (monsoon season) during the night/day, and the duration of enhanced mixing layer heights during daytime (around 12 hours (pre-monsoon season) to 8 hours (winter)). During the monsoon

  3. Radiolytic synthesis of carbon-supported PtRu nanoparticles using high-energy electron beam: effect of pH control on the PtRu mixing state and the methanol oxidation activity

    International Nuclear Information System (INIS)

    Ohkubo, Yuji; Kageyama, Satoru; Seino, Satoshi; Nakagawa, Takashi; Kugai, Junichiro; Nitani, Hiroaki; Ueno, Koji; Yamamoto, Takao A.

    2013-01-01

    Electrode catalysts composed of carbon-supported PtRu nanoparticles (PtRu/C) for use as a direct methanol fuel cell anode were synthesized by the reduction of precursor ions in an aqueous solution via irradiation with a high-energy electron beam. The effect of pH control in the precursor solution on the PtRu mixing state and the methanol oxidation activity was studied in order to enhance the catalytic activity for methanol oxidation. The PtRu/C structures were characterized by transmission electron microscopy, inductively coupled plasma atomic emission spectrometry, X-ray fluorescence spectrometry, and X-ray diffraction and X-ray absorption fine structure techniques. The methanol oxidation activity was evaluated by linear sweep voltammetry. The initial pH of the precursor solution has little influence on the average grain size for the metal particles (approximately 3.5 nm) on the carbon particle supports, but the dispersibility of the metal particles, PtRu mixing state, and methanol oxidation activity differed. The maintenance of a low pH in the precursor solution gave the best dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles, whereas, a high pH gave the best PtRu mixing state and the highest oxidation current although a low dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles was obtained. The PtRu mixing state strongly correlated with the methanol oxidation current. In addition, a high pH was more effective for PtRu mixing when using an electron beam irradiation reduction method, because the complexation reaction of the chelating agents was improved, which resulted in an enhancement of the catalytic activity for methanol oxidation.

  4. Radiolytic synthesis of carbon-supported PtRu nanoparticles using high-energy electron beam: effect of pH control on the PtRu mixing state and the methanol oxidation activity

    Energy Technology Data Exchange (ETDEWEB)

    Ohkubo, Yuji, E-mail: okubo@mit.eng.osaka-u.ac.jp; Kageyama, Satoru; Seino, Satoshi; Nakagawa, Takashi; Kugai, Junichiro [Osaka University, Graduate School of Engineering (Japan); Nitani, Hiroaki [High Energy Accelerator Research Organization (KEK), Institute of Materials Structure Science (Japan); Ueno, Koji [Japan Electron Beam Irradiation Service Ltd (Japan); Yamamoto, Takao A. [Osaka University, Graduate School of Engineering (Japan)

    2013-05-15

    Electrode catalysts composed of carbon-supported PtRu nanoparticles (PtRu/C) for use as a direct methanol fuel cell anode were synthesized by the reduction of precursor ions in an aqueous solution via irradiation with a high-energy electron beam. The effect of pH control in the precursor solution on the PtRu mixing state and the methanol oxidation activity was studied in order to enhance the catalytic activity for methanol oxidation. The PtRu/C structures were characterized by transmission electron microscopy, inductively coupled plasma atomic emission spectrometry, X-ray fluorescence spectrometry, and X-ray diffraction and X-ray absorption fine structure techniques. The methanol oxidation activity was evaluated by linear sweep voltammetry. The initial pH of the precursor solution has little influence on the average grain size for the metal particles (approximately 3.5 nm) on the carbon particle supports, but the dispersibility of the metal particles, PtRu mixing state, and methanol oxidation activity differed. The maintenance of a low pH in the precursor solution gave the best dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles, whereas, a high pH gave the best PtRu mixing state and the highest oxidation current although a low dispersibility of the PtRu nanoparticles supported on the surface of the carbon particles was obtained. The PtRu mixing state strongly correlated with the methanol oxidation current. In addition, a high pH was more effective for PtRu mixing when using an electron beam irradiation reduction method, because the complexation reaction of the chelating agents was improved, which resulted in an enhancement of the catalytic activity for methanol oxidation.

  5. Carbon isotopes in mollusk shell carbonates

    Science.gov (United States)

    McConnaughey, Ted A.; Gillikin, David Paul

    2008-10-01

    Mollusk shells contain many isotopic clues about calcification physiology and environmental conditions at the time of shell formation. In this review, we use both published and unpublished data to discuss carbon isotopes in both bivalve and gastropod shell carbonates. Land snails construct their shells mainly from respired CO2, and shell δ13C reflects the local mix of C3 and C4 plants consumed. Shell δ13C is typically >10‰ heavier than diet, probably because respiratory gas exchange discards CO2, and retains the isotopically heavier HCO3 -. Respired CO2 contributes less to the shells of aquatic mollusks, because CO2/O2 ratios are usually higher in water than in air, leading to more replacement of respired CO2 by environmental CO2. Fluid exchange with the environment also brings additional dissolved inorganic carbon (DIC) into the calcification site. Shell δ13C is typically a few ‰ lower than ambient DIC, and often decreases with age. Shell δ13C retains clues about processes such as ecosystem metabolism and estuarine mixing. Ca2+ ATPase-based models of calcification physiology developed for corals and algae likely apply to mollusks, too, but lower pH and carbonic anhydrase at the calcification site probably suppress kinetic isotope effects. Carbon isotopes in biogenic carbonates are clearly complex, but cautious interpretation can provide a wealth of information, especially after vital effects are better understood.

  6. Promoting effect of active carbons on methanol dehydrogenation on sodium carbonate - hydrogen spillover

    OpenAIRE

    Su, S.; Prairie, M.; Renken, A.

    1993-01-01

    Methanol dehydrogenation to formaldehyde was conducted in a fixed-bed flow reactor with sodium carbonate catalyst mixed with active carbons or transition metals. The additives promoted the reaction rate at 880-970 K without modifying formaldehyde selectivity. This effect increases with increasing carbon content in the carbon-carbonate mixture. Activation energy of methanol conversion is the same for the mixture and the carbonate alone. Temperature-programmed desorption experiments showed that...

  7. Global zero-carbon energy pathways using viable mixes of nuclear and renewables

    International Nuclear Information System (INIS)

    Hong, Sanghyun; Bradshaw, Corey J.A.; Brook, Barry W.

    2015-01-01

    Highlights: • A proper mix of nuclear power and renewables achieves sustainable energy future. • A high nuclear share provides cost and land effectiveness compared to nuclear-free. • Only-renewable mix will increase negative economic and environmental impacts. • A deployment of advanced reactor technologies is essential to overcome limitations. - Abstract: What are the most viable global pathways for a major expansion of zero-carbon emissions electricity sources given the diversity of regional technical, socio-political and economic constraints? We modelled a range of zero-emissions energy scenarios across nations that were designed to meet projected final energy demand in 2060, and optimised to derive the best globally aggregated results in terms of minimising costs and land use (a surrogate for environmental impacts). We found that a delayed energy transition to a zero-emissions pathway will decrease investment costs (−$3,431 billion), but increase cumulative CO 2 emissions (additional 696 Gt). A renewable-only scenario would convert >7.4% of the global land area to energy production, whereas a maximum nuclear scenario would affect <0.4% of land area, including mining, spent-fuel storage, and buffer zones. Moreover, a nuclear-free pathway would involve up to a 50% greater cumulative capital investment compared to a high nuclear penetration scenario ($73.7 trillion). However, for some nations with a high current share of renewables and a low projected future energy demand (e.g., Norway), pursuit of a higher nuclear share is suboptimal. In terms of the time frame for replacement of fossil fuels, achieving a global nuclear share of about 50% by 2060 would be a technically and economically plausible target if progressing at a pace of the average historical growth of nuclear power penetration in France from 1970 to 1986 (0.28 MWh person −1 year -1 ). For effective climate-change mitigation, a high penetration of nuclear in association with a nationally

  8. Rigid Polyurethane Nanocomposites Prepared by Direct Incorporation: Effects of Nanoclay, Carbon Nanotubes and Mixing Speed on Physical and Morphological Properties

    Science.gov (United States)

    Ramadhoni, Benni; Ujianto, Onny; Nadapdap, Maxwell

    2018-03-01

    Rigid polyurethane (PU) nanocomposites were fabricated via solution mixing of PU, nanoclay and multiwalled carbon nanotubes (MWCNT) according to full factorial DoE. The nanoclay and MWCNT concentration as well as mixing speed were varied. The effects of controlled variables on reduced compressive strength, fire retardancy, hardness and morphological properties were analized. In general, the results showed that incorporation of nanofillers into PU matrix successfully elevated nanocomposites performance. The properties changed from -12% to 45% for reduced compressive strength, 9% to 30% for reduced fire retardancy and -32% to 101% for reduced hardness. The results suggested that the improvements were affected by nanoclay dispersion that acted as nucleating agent which resulted in smaller close cells of PU structures.

  9. Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the UK

    Science.gov (United States)

    McMeeking, G. R.; Morgan, W. T.; Flynn, M.; Highwood, E. J.; Turnbull, K.; Haywood, J.; Coe, H.

    2011-05-01

    Black carbon (BC) aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2) measurements of refractory BC (rBC) mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the UK. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA) operated by the Facility for Airborne Atmospheric Measurements (FAAM). We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS) and used positive matrix factorization to separate hydrocarbon-like (HOA) and oxygenated organic aerosols (OOA). We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NOx) ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NOx and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA) did change for different air masses, with lower SSA observed in

  10. Rotational mixing in carbon-enhanced metal-poor stars with s-process enrichment

    Science.gov (United States)

    Matrozis, E.; Stancliffe, R. J.

    2017-10-01

    Carbon-enhanced metal-poor (CEMP) stars with s-process enrichment (CEMP-s) are believed to be the products of mass transfer from an asymptotic giant branch (AGB) companion, which has long since become a white dwarf. The surface abundances of CEMP-s stars are thus commonly assumed to reflect the nucleosynthesis output of the first AGB stars. We have previously shown that, for this to be the case, some physical mechanism must counter atomic diffusion (gravitational settling and radiative levitation) in these nearly fully radiative stars, which otherwise leads to surface abundance anomalies clearly inconsistent with observations. Here we take into account angular momentum accretion by these stars. We compute in detail the evolution of typical CEMP-s stars from the zero-age main sequence, through the mass accretion, and up the red giant branch for a wide range of specific angular momentum ja of the accreted material, corresponding to surface rotation velocities, vrot, between about 0.3 and 300 kms-1. We find that only for ja ≳ 1017 cm2s-1 (vrot > 20 kms-1, depending on mass accreted) angular momentum accretion directly causes chemical dilution of the accreted material. This could nevertheless be relevant to CEMP-s stars, which are observed to rotate more slowly, if they undergo continuous angular momentum loss akin to solar-like stars. In models with rotation velocities characteristic of CEMP-s stars, rotational mixing primarily serves to inhibit atomic diffusion, such that the maximal surface abundance variations (with respect to the composition of the accreted material) prior to first dredge-up remain within about 0.4 dex without thermohaline mixing or about 0.5-1.5 dex with thermohaline mixing. Even in models with the lowest rotation velocities (vrot ≲ 1 kms-1), rotational mixing is able to severely inhibit atomic diffusion, compared to non-rotating models. We thus conclude that it offers a natural solution to the problem posed by atomic diffusion and cannot be

  11. Isotopic mixing in carbon monoxide catalyzed by zinc oxide

    International Nuclear Information System (INIS)

    Carnisio, G.; Garbassi, F.; Petrini, G.; Parravano, G.

    1978-01-01

    The rate of the isotopic mixing in CO has been studied at 300 0 C, for CO partial pressures from 6 to 100 Torr and a total pressure of 250 Torr on ZnO catalysts. Significant deviations from a first-order rate in p/sub co/ were found. The rate of oxygen exchange between ZnO and gas-phase CO was also measured and the results were employed to calculate the fraction of surface sites active for the CO isotopic mixing. Values on the order of 0.001 were found. The turnover rate and surface collision efficiency varied between 0.7 and 107 min -1 and 0.13 and 2.24 x 10 -8 , respectively. H 2 additions to CO increased the rate of isotopic mixing, whereas the rate of H 2 + D 2 was decreased by the presence of CO. The H 2 + D 2 rate was faster than that of isotopic mixing in CO, but as the ratio p/sub H 2 //p/sub co/ decreased the rates became about equal. It is argued that on ZnO samples, in which the rate of CO isotopic mixing and the rate of ZnO--CO oxygen exchange were influenced in a similar manner by the CO pressure, the isotopic mixing in CO took place via the ZnO oxygen, while oxide oxygen participation was not kinetically significant for ZnO samples in which the two reactions had different kinetics. The crucial factor controlling the path followed by the isotopic mixing in CO seems to be the surface Zn/O ratio, since a close correlation was found between the former and the reaction kinetics of the CO isotopic mixing reaction. Solid-state conditions which may vary the Zn/O surface ratio (foreign additions) are indicated. The implications of these findings to the problem of product selectivity from CO-H 2 mixtures reacting on metal oxide surfaces are discussed

  12. Mixing-Structure Relationship in Jet-Stirred Reactors

    KAUST Repository

    Ayass, Wassim W.; Nasir, Ehson Fawad; Farooq, Aamir; Sarathy, Mani

    2016-01-01

    of these geometrical parameters on mixing. The mixing was studied at ambient conditions using laser absorption spectroscopy to follow the exit concentration of a tracer gas, carbon dioxide, after a step change in its input flow. The results indicate that the use of a

  13. Separation of cannabinoids on three different mixed-mode columns containing carbon/nanodiamond/amine-polymer superficially porous particles.

    Science.gov (United States)

    Hung, Chuan-Hsi; Zukowski, Janusz; Jensen, David S; Miles, Andrew J; Sulak, Clayton; Dadson, Andrew E; Linford, Matthew R

    2015-09-01

    Three mixed-mode high-performance liquid chromatography columns packed with superficially porous carbon/nanodiamond/amine-polymer particles were used to separate mixtures of cannabinoids. Columns evaluated included: (i) reversed phase (C18 ), weak anion exchange, 4.6 × 33 mm, 3.6 μm, and 4.6 × 100 mm, 3.6 μm, (ii) reversed phase, strong anion exchange (quaternary amine), 4.6×33 mm, 3.6 μm, and (iii) hydrophilic interaction liquid chromatography, 4.6 × 150 mm, 3.6 μm. Different selectivities were achieved under various mobile phase and stationary phase conditions. Efficiencies and peak capacities were as high as 54 000 N/m and 56, respectively. The reversed phase mixed-mode column (C18 ) retained tetrahydrocannabinolic acid strongly under acidic conditions and weakly under basic conditions. Tetrahydrocannabinolic acid was retained strongly on the reversed phase, strong anion exchange mixed-mode column under basic polar organic mobile phase conditions. The hydrophilic interaction liquid chromatography column retained polar cannabinoids better than the (more) neutral ones under basic conditions. A longer reversed phase (C18 ) mixed-mode column (4.6 × 100 mm) showed better resolution for analytes (and a contaminant) than a shorter column. Fast separations were achieved in less than 5 min and sometimes 2 min. A real world sample (bubble hash extract) was also analyzed by gradient elution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Upgrading of glycerol from biodiesel synthesis with dimethyl carbonate on reusable Sr–Al mixed oxide catalysts

    International Nuclear Information System (INIS)

    Algoufi, Y.T.; Akpan, U.G.; Kabir, G.; Asif, M.; Hameed, B.H.

    2017-01-01

    Highlights: • Catalytic transesterification with dimethyl carbonate (DMC) converts glycerol into glycerol carbonate (GLC). • DMC and Sr_x–Al catalysts affect the reaction mechanisms that convert glycerol into GLC. • The morphology and textural structure of Sr_x–Al catalysts perpetuate catalytic activity. • The atomic ratio of Sr/Al has a unique effect on Sr–Al catalytic activity. • Sr_0_._5–Al catalyst exhibits limited leaching after five reaction cycles. - Abstract: The high demand for renewable energy has led to the upsurge of methanol-assisted biodiesel synthesis. Therefore, glycerol as a byproduct entered the waste stream given the oversupply of biodiesel to the market. The dimethyl carbonate (DMC)-assisted transesterification of glycerol on a catalyst has been a popular approach for converting glycerol into valuable glycerol carbonate (GLC). The synthesis of GLC from the DMC-assisted transesterification of glycerol on mixed oxide catalysts (Sr_x–Al) with different Sr/Al ratios was examined in this study. A glycerol conversion of 99.4% and a GLC yield of 100% were achieved in a catalyst with Sr/Al = 0.5 (Sr_0_._5–Al). Both values are higher than those in catalysts synthesized with Sr/Al = 0.25 and 0.75. The Sr_0_._5–Al catalyst withstood five transesterification reaction cycles without a serious deactivation induced by the leaching of active SrO. Therefore, the Sr_0_._5–Al catalyst is suitable for consecutive uses in the DMC-assisted transesterification of glycerol with DMC into GLC.

  15. Crown-To-Rhizosphere Carbon Transfer In A Temperate Mixed Forest

    Science.gov (United States)

    Siegwolf, R. T.; Steinmann, K.; Saurer, M.; Koerner, C.

    2005-12-01

    Flux measurements across a range of (managed) European forests showed that ecosystem respiration amounts up to 80 percent of gross primary production (Janssens et al. 2001), the rest is in large sequestered into biomass. According to Malhi et al. (1999) soil respiration accounts for 60-70 percent of total forest ecosystem respiration. A considerable part is released as CO2 via belowground plant component (autotrophic) and soil micro-organism (heterotrophic) respiration. Recent studies on the autotrophic and heterotrophic respiratory fluxes indicate that the proportion of the autotrophic respiration was most likely underestimated (Hoegberg et al, 2001). Furthermore, highly diverging lengths of time have been estimated between the synthesis of carbohydrates and their availability in the rhizosphere. The goal of the presented study was to i) estimate the transport time for new photosynthates from the leaves to the rhizosphere, ii) determine the spatial distribution of these products, and iii) detect a seasonal course in the autotrophic and heterotrophic respiration of freshly formed assimilates. This study was carried out in a temperate mixed forest (The Swiss Canopy Crane Project in Hofstetten near Basel, Switzerland, cf. Pepin and Koerner 2002, Koerner et al, 2005), exposed to an elevated mean CO2 concentration of 530 ppm. The added CO2 originated from fossil fuel combustion and was depleted in 13C, thus serving as an ideal tracer. Based on the isotopic signature of the soil CO2 it was shown that freshly assimilated carbohydrates were transferred to the rhizosphere within ca. 5 days. The spatial variability was considerable and could mostly be explained with the varying tree population, whereas, the broad-leafed area revealed a more negative d13C value than the conifers. A distinct seasonal course in soil ?13C of the CO2 concentration indicated a seasonal variation in the crown-to-rhizosphere carbon transfer Steinmann et al (2004). Hoegberg P, et al. (2001) Large

  16. Debates of the Vista 2011 Colloquium 'Towards a low carbon energy mix: which role for nuclear?'

    International Nuclear Information System (INIS)

    Barre, Bertrand; Garribba, Massimo; ); Poyer, Luc; Bigot, Bernard; Ducre, Henri; Giraud, Yves; Wehrling, Yann

    2011-12-01

    During two debates (the first one addresses stakes and challenges at the international level, and the second one addresses the French context), the interveners discuss the evolution of energy mixes at the international level and the share of nuclear energy. They address the conditions under which several energy types are being or can be used within the frame of energy transition, and in a context where the growth of energy consumption is mainly due the development of emerging countries. They discuss how western countries will be able to finance huge investments required by the climate challenge for the development of low carbon energies and energy efficiency in a context of economic recession. They discuss the issue of nuclear energy safety after Fukushima, how the share of nuclear energy could be decreased and whether it is possible, which will be the role of renewable energies, how energy mixes are organised at the international level (different approaches in different countries, differences between France and Germany in a European context). They also address the issues related to the EPR (costs, perspectives)

  17. Optimization of mixing process and effect of multi-walled carbon nanotubes on tensile properties of unsaturated polyester resin in composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Hoang, Van-Tho; Yum, Young-Jin [University of Ulsan, Ulsan (Korea, Republic of)

    2017-04-15

    Multi-walled carbon nanotubes (MWCNTs) were mixed with Unsaturated polyester resin (UPR) using the stir method at high temperatures. The mixing temperature and hardener ratio were optimized based on compression properties and the exothermic temperature. In the experiment, 60 °C and 1 wt.% of Methyl ethyl ketone peroxide (MEKP) were chosen for the mixing condition and catalyst concentration, respectively. MWCNTs with different weight fractions (0.05, 0.1, 0.2 and 0.3 wt.%) were dispersed to investigate the effect of MWCNTs on tensile properties of the UPR, and it was found that 0.1 wt.% of MWCNTs showed the best performance in this range of fiber weight fraction due to a higher strength (42.14 %), modulus (14.33 %) and fracture strain (37.17 %) than pure UPR. The state of dispersion and arrangement of fibers were examined by a Field emission Scanning electron microscope (FE-SEM) according to fracture surfaces. Similarly, the FE-SEM also showed better results with 0.1 wt.% of MWCNTs mixed in the UPR.

  18. Contrasting effects of temperature and winter mixing on the seasonal and inter-annual variability of the carbonate system in the Northeast Atlantic Ocean

    Directory of Open Access Journals (Sweden)

    C. Dumousseaud

    2010-05-01

    Full Text Available Future climate change as a result of increasing atmospheric CO2 concentrations is expected to strongly affect the oceans, with shallower winter mixing and consequent reduction in primary production and oceanic carbon drawdown in low and mid-latitudinal oceanic regions. Here we test this hypothesis by examining the effects of cold and warm winters on the carbonate system in the surface waters of the Northeast Atlantic Ocean for the period between 2005 and 2007. Monthly observations were made between the English Channel and the Bay of Biscay using a ship of opportunity program. During the colder winter of 2005/2006, the maximum depth of the mixed layer reached up to 650 m in the Bay of Biscay, whilst during the warmer (by 2.6 ± 0.5 °C winter of 2006/2007 the mixed layer depth reached only 300 m. The inter-annual differences in late winter concentrations of nitrate (2.8 ± 1.1 μmol l−1 and dissolved inorganic carbon (22 ± 6 μmol kg−1, with higher concentrations at the end of the colder winter (2005/2006, led to differences in the dissolved oxygen anomaly and the chlorophyll α-fluorescence data for the subsequent growing season. In contrast to model predictions, the calculated air-sea CO2 fluxes (ranging from +3.7 to −4.8 mmol m−2 d−1 showed an increased oceanic CO2 uptake in the Bay of Biscay following the warmer winter of 2006/2007 associated with wind speed and sea surface temperature differences.

  19. The Effect of Rubber Mixing Process on The Curing Characteristics of Natural Rubber

    Directory of Open Access Journals (Sweden)

    Abu Hasan

    2013-04-01

    Full Text Available This research is aimed at studying the relationship between rubber mixing processes and curing characteristics of natural rubber. The curing characteristic analysis was carried out through a natural rubber formula having been masticated and mixed, followed by curing. As many as four mastication methods were finely applied; each respected four sequences of rubber mixing process. In the first method, rubber was masticated for 5 minutes and then rubber chemicals and carbon black N 330 were  simultaneously added. In the second and the third methods, rubber was masticated for 1 minute and then carbon blacks and rubber chemicals were also simultaneously added but using different type of fillers. In the fourth method, rubber was masticated for 3 minutes and then rubber chemicals and carbon black were subsequently added. The additions of rubber chemicals and carbon blacks to the masticated rubber were distinguished by the sequence and time allocated for each mixing process. The carbon blacks were added in two stages by which 10 phr was added first and the remaining 40 phr was added later along with oil. In another method, ratios of the carbon blacks addition (as done in the first  and the second stages were 20:30, 30:20, and 40:10. The examination results showed that rubber mixing process gave an impact on the changes of curing characteristics. They were much affected by the method of carbon black addition. The mixing temperature also had an effect on both curing time and curing rate in which the higher the mixing temperature, the lower the curing time and curing rate. Vulcanization temperature also affected the curing time and curing rate in which the higher the vulcanization temperature, the lower the curing time and the higher the curing rate. Lastly, particle size of carbon black also gave an impact on the curing time and curing rate in which the smaller the particle size, the lower the curing time and the higher the curing rate.

  20. Method of producing carbon coated nano- and micron-scale particles

    Science.gov (United States)

    Perry, W. Lee; Weigle, John C; Phillips, Jonathan

    2013-12-17

    A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

  1. Mercury emissions control technologies for mixed waste thermal treatment

    International Nuclear Information System (INIS)

    Chambers, A.; Knecht, M.; Soelberg, N.; Eaton, D.

    1997-01-01

    EPA has identified wet scrubbing at low mercury feedrates, as well as carbon adsorption via carbon injection into the offgas or via flow through fixed carbon beds, as control technologies that can be used to meet the proposed Maximum Achievable Control Technology (MACT) rule limit for mercury emissions from hazardous waste incinerators. DOE is currently funding demonstrations of gold amalgamation that may also control mercury to the desired levels. Performance data from a variety of sources was reviewed to determine ranges of achievable mercury control. Preliminary costs were estimated for using these technologies to control mercury emissions from mixed waste incineration. Mercury emissions control for mixed waste incineration may need to be more efficient than for incineration of other hazardous wastes because of higher mercury concentrations in some mixed waste streams. However, mercury control performance data for wet scrubbing and carbon adsorption is highly variable. More information is needed to demonstrate control efficiencies that are achievable under various design and operating conditions for wet scrubbing, carbon adsorption, and gold amalgamation technologies. Given certain assumptions made in this study, capital costs, operating costs, and lifecycle costs for carbon injection, carbon beds, and gold amalgamation generally vary for different assumed mercury feedrates and for different offgas flowrates. Assuming that these technologies can in fact provide the necessary mercury control performance, each of these technologies may be less costly than the others for certain mercury feedrates and the offgas flowrates

  2. Preparation, physical-chemical characterisation and cytocompatibility of calcium carbonate cements

    OpenAIRE

    Combes, Christèle; Miao, Baoji; Bareille, Reine; Rey, Christian

    2006-01-01

    The feasibility of calcium carbonate cements involving the recrystallisation of metastable calcium carbonate varieties has been demonstrated. Calcium carbonate cement compositions presented in this paper can be prepared straightforwardly by simply mixing water (liquid phase) with two calcium carbonate phases (solid phase) which can be easily obtained by precipitation. An original cement composition was obtained by mixing amorphous calcium carbonate and vaterite with an aqueous medium. The cem...

  3. Metal-doped single-walled carbon nanotubes and production thereof

    Science.gov (United States)

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

    2007-01-09

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

  4. Effect of polymer type on characterization and filtration performances of multi-walled carbon nanotubes (MWCNT)-COOH-based polymeric mixed matrix membranes.

    Science.gov (United States)

    Sengur-Tasdemir, Reyhan; Mokkapati, Venkata R S S; Koseoglu-Imer, Derya Y; Koyuncu, Ismail

    2018-05-01

    Multi-walled carbon nanotubes (MWCNTs) can be used for the fabrication of mixed matrix polymeric membranes that can enhance filtration perfomances of the membranes by modifying membrane surface properties. In this study, detailed characterization and filtration performances of MWCNTs functionalized with COOH group, blended into polymeric flat-sheet membranes were investigated using different polymer types. Morphological characterization was carried out using atomic force microscopy, scanning electron microscopy and contact angle measurements. For filtration performance tests, protein, dextran, E. coli suspension, Xanthan Gum and real activated sludge solutions were used. Experimental data and analyses revealed that Polyethersulfone (PES) + MWCNT-COOH mixed matrix membranes have superior performance abilities compared to other tested membranes.

  5. Thermo-mechanical characterization of epoxy nanocomposites with different carbon nanotube distributions obtained by solvent aided and direct mixing.

    Directory of Open Access Journals (Sweden)

    M. Zarrelli

    2012-07-01

    Full Text Available Two different routes, namely solvent aided dispersion and direct mixing, were employed to disperse Multi-Walled Carbon Nanotubes (MWNTs into a mono-component epoxy system used as matrix for advanced composites. In the first route, MWCNTs were diluted in three different solvents (acetone, sodium dodecyl sulfate and ethanol and then mixed with the matrix by tip sonication. In the second case, carbonaceous nanoparticles were added directly into the hosting system and dispersion was carried out by using three different techniques (mechanical stirring, magnetic agitation and tip sonication. The effects of the solvents and agitation energy were investigated by optical microscopy at micron level, in order assess the more efficient dispersion procedure for the considered epoxy system. It was demonstrated that parameters associated with direct mixing rather than solvent solubility govern MWCNT dispersion. Optical analysis of the nanocomposite morphology evidenced a very low density of MWCNTs micron sized aggregates in the case of direct mixed tip sonicated samples if compared to those obtained by solution aided dispersion. In addition, nanocomposites obtained by sonication showed the lowest density of MWCNTs micron sized aggregates, also when compared with mechanically and magnetically stirred system. Dynamic Mechanical Analysis (DMA and Thermo-Mechanical Analysis (TMA results confirm the final result that among the considered direct mixing techniques, the direct tip sonication represents the most efficient route for MWCNT dispersion. Moreover, the mixing temperature of the hosting matrix system represents a fundamental feature in enhancing the MWCNT de-bundling and dispersion. Small X-ray Scattering analysis revealed that a nanosized structure of nanotubes is formed in the case of the tip sonicated samples that is heuristically correlated with both the maximum enhancement of mechanical modulus and the maximum reduction of thermal expansion coefficients.

  6. A New Method to Obtain the Black Carbon Mixing State of Biomass and Combustion Aerosols

    Science.gov (United States)

    Irwin, M.; Liu, D.; Joshi, R.; Allan, J. D.; Coe, H.; Flynn, M.; Olfert, J. S.; Broda, K.; Fu, P.; Sun, Y.; Ge, X.; Wang, J.

    2017-12-01

    Black carbon particles (BC) significantly contribute to warming effects in the atmosphere, altering weather systems, and pose significant health risks. These impacts are especially efficient at regional hotspots with high emissions of pollutants, such as in fast-developing megacities. These urban environments have the most population exposure, and improving the understanding of the sources and the processing of pollutants in these environments is critical in guiding policy making. Here we present the results of BC characterization in Beijing during the winter of 2016 (10th Nov-10th Dec), as part of a large joint UK-China field experiment. During this experiment, we successfully gathered 4 weeks of continuous measurements, including several severe pollution events in Beijing. MethodologyThe mixing state of BC, which is how BC is associated with non-BC material (its coating) within a particle, is crucial to determine its lifetime in the atmosphere and also its optical properties. However precisely quantifying the BC mixing state has posed a challenge, in part due to complex particle morphology. We have applied morphology-independent measurements of BC mixing state on a single-particle basis throughout this experiment: mono-dispersed particle mass (MP) is selected using a Centrifugal Particle Mass Analyser (CPMA, Cambustion Ltd) and a single particle soot photometer (SP2, DMT inc.) was used downstream of the CPMA to measure the refractory BC mass (MrBC). The full scan of CPMA masses (21 mass bins covering most of MP) are performed every half hour, following polydispersed particles measured without running CPMA.

  7. Highly thermal conductive carbon fiber/boron carbide composite material

    International Nuclear Information System (INIS)

    Chiba, Akio; Suzuki, Yasutaka; Goto, Sumitaka; Saito, Yukio; Jinbo, Ryutaro; Ogiwara, Norio; Saido, Masahiro.

    1996-01-01

    In a composite member for use in walls of a thermonuclear reactor, if carbon fibers and boron carbide are mixed, since they are brought into contact with each other directly, boron is reacted with the carbon fibers to form boron carbide to lower thermal conductivity of the carbon fibers. Then, in the present invention, graphite or amorphous carbon is filled between the carbon fibers to provide a fiber bundle of not less than 500 carbon fibers. Further, the surface of the fiber bundle is coated with graphite or amorphous carbon to suppress diffusion or solid solubilization of boron to carbon fibers or reaction of them. Then, lowering of thermal conductivity of the carbon fibers is prevented, as well as the mixing amount of the carbon fiber bundles with boron carbide, a sintering temperature and orientation of carbon fiber bundles are optimized to provide a highly thermal conductive carbon fiber/boron carbide composite material. In addition, carbide or boride type short fibers, spherical graphite, and amorphous carbon are mixed in the boron carbide to prevent development of cracks. Diffusion or solid solubilization of boron to carbon fibers is reduced or reaction of them if the carbon fibers are bundled. (N.H.)

  8. Stable carbon, nitrogen and sulfur isotopes in non-carbonate fractions of cold-seep carbonates

    Science.gov (United States)

    Feng, Dong; Peng, Yongbo; Peckmann, Jörn; Roberts, Harry; Chen, Duofu

    2017-04-01

    Sulfate-driven anaerobic oxidation of methane (AOM) supports chemosynthesis-based communities and limits the release of methane from marine sediments. This process promotes the formation of carbonates close to the seafloor along continental margins. The geochemical characteristics of the carbonate minerals of these rocks are increasingly understood, questions remain about the geochemical characteristics of the non-carbonate fractions. Here, we report stable carbon, nitrogen and sulfur isotope patterns in non-carbonate fractions of seep carbonates. The authigenic carbonates were collected from three modern seep provinces (Black Sea, Gulf of Mexico, and South China Sea) and three ancient seep deposits (Marmorito, northern Italy, Miocene; SR4 deposit of the Lincoln Creek Formation and Whiskey Creek, western Washington, USA, Eocene to Oligocene). The δ13C values of non-carbonate fractions range from ˜-25‰ to -80‰ VPDB. These values indicate that fossil methane mixed with varying amounts of pelagic organic matter is the dominant source of carbon in these fractions. The relatively small offset between the δ34S signatures of the non-carbonate fractions and the respective sulfide minerals suggests that locally produced hydrogen sulfide is the main source of sulfur in seep environments. The δ15N values of the non-carbonate fractions are generally lower than the corresponding values of deep-sea sediments, suggesting that organic nitrogen is mostly of a local origin. This study reveals the potential of using δ13C, δ15N, δ34S values to discern seep and non-seep deposits. In cases where δ13Ccarbonate values are only moderately low due to mixing processes and lipid biomarkers have been erased in the course of burial, it is difficult to trace back AOM owing to the lack of other records. This problem is even more pronounced when authigenic carbonate is not available in ancient seep environments. Acknowledgments: The authors thank BOEM and NOAA for their years' support

  9. [Organic carbon and carbon mineralization characteristics in nature forestry soil].

    Science.gov (United States)

    Yang, Tian; Dai, Wei; An, Xiao-Juan; Pang, Huan; Zou, Jian-Mei; Zhang, Rui

    2014-03-01

    Through field investigation and indoor analysis, the organic carbon content and organic carbon mineralization characteristics of six kinds of natural forest soil were studied, including the pine forests, evergreen broad-leaved forest, deciduous broad-leaved forest, mixed needle leaf and Korean pine and Chinese pine forest. The results showed that the organic carbon content in the forest soil showed trends of gradual decrease with the increase of soil depth; Double exponential equation fitted well with the organic carbon mineralization process in natural forest soil, accurately reflecting the mineralization reaction characteristics of the natural forest soil. Natural forest soil in each layer had the same mineralization reaction trend, but different intensity. Among them, the reaction intensity in the 0-10 cm soil of the Korean pine forest was the highest, and the intensities of mineralization reaction in its lower layers were also significantly higher than those in the same layers of other natural forest soil; comparison of soil mineralization characteristics of the deciduous broad-leaved forest and coniferous and broad-leaved mixed forest found that the differences of litter species had a relatively strong impact on the active organic carbon content in soil, leading to different characteristics of mineralization reaction.

  10. Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the United Kingdom

    Science.gov (United States)

    McMeeking, G. R.; Morgan, W. T.; Flynn, M.; Highwood, E. J.; Turnbull, K.; Haywood, J.; Coe, H.

    2011-09-01

    Black carbon (BC) aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2) measurements of refractory BC (rBC) mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the United Kingdom. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA) operated by the Facility for Airborne Atmospheric Measurements (FAAM). We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS) and used positive matrix factorization to separate hydrocarbon-like (HOA) and oxygenated organic aerosols (OOA). We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NOx) ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NOx and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA) did change for different air masses, with lower SSA

  11. Black carbon aerosol mixing state, organic aerosols and aerosol optical properties over the United Kingdom

    Directory of Open Access Journals (Sweden)

    G. R. McMeeking

    2011-09-01

    Full Text Available Black carbon (BC aerosols absorb sunlight thereby leading to a positive radiative forcing and a warming of climate and can also impact human health through their impact on the respiratory system. The state of mixing of BC with other aerosol species, particularly the degree of internal/external mixing, has been highlighted as a major uncertainty in assessing its radiative forcing and hence its climate impact, but few in situ observations of mixing state exist. We present airborne single particle soot photometer (SP2 measurements of refractory BC (rBC mass concentrations and mixing state coupled with aerosol composition and optical properties measured in urban plumes and regional pollution over the United Kingdom. All data were obtained using instrumentation flown on the UK's BAe-146-301 large Atmospheric Research Aircraft (ARA operated by the Facility for Airborne Atmospheric Measurements (FAAM. We measured sub-micron aerosol composition using an aerosol mass spectrometer (AMS and used positive matrix factorization to separate hydrocarbon-like (HOA and oxygenated organic aerosols (OOA. We found a higher number fraction of thickly coated rBC particles in air masses with large OOA relative to HOA, higher ozone-to-nitrogen oxides (NOx ratios and large concentrations of total sub-micron aerosol mass relative to rBC mass concentrations. The more ozone- and OOA-rich air masses were associated with transport from continental Europe, while plumes from UK cities had higher HOA and NOx and fewer thickly coated rBC particles. We did not observe any significant change in the rBC mass absorption efficiency calculated from rBC mass and light absorption coefficients measured by a particle soot absorption photometer despite observing significant changes in aerosol composition and rBC mixing state. The contributions of light scattering and absorption to total extinction (quantified by the single scattering albedo; SSA did change for

  12. Carbon nanotube-like materials in the exhaust from a diesel engine using gas oil/ethanol mixing fuel with catalysts and sulfur.

    Science.gov (United States)

    Suzuki, Shunsuke; Mori, Shinsuke

    2017-08-01

    Particulate matter from a diesel engine, including soot and carbon nanomaterials, was collected on a sampling holder and the structure of the materials was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). As a result of employing gas oil/ethanol mixing fuel with sulfur and ferrocene/molybdenum as catalyst sources, formation of carbon nanotubes (CNT)-like materials in addition to soot was observed in the exhaust gas from a diesel engine. It was revealed that CNT-like materials were included among soot in our system only when the following three conditions were satisfied simultaneously: high ethanol fraction in fuel, high sulfur loading, and presence of catalyst sources in fuel. This study confirmed that if at least one of these three conditions was not satisfied, CNT-like materials were not observed in the exhaust from a diesel engine. These experimental results shown in this work provide insights into understanding CNT-like material formation mechanism in a diesel engine. Recent papers reported that carbon nanotube-like materials were included in the exhaust gas from engines, but conditions for carbon nanotube-like material formation have not been well studied. This work provides the required conditions for carbon nanotube-like material growth in a diesel engine, and this will be helpful for understanding the carbon nanotube-like material formation mechanism and taking countermeasures to preventing carbon nanotube-like material formation in a diesel engine.

  13. Ageing of Dry Cement Mixes for Finishing Purposes

    Directory of Open Access Journals (Sweden)

    Bronius VEKTARIS

    2013-09-01

    Full Text Available Dry building mixes, stored in the air, absorb water vapor and CO2 gas and ageing because properties of binding materials, mostly Portland cement, deteriorate after its prehydration and carbonation. In this paper the ageing singularities of dry cement mixes for finishing purposes and additives for retarding this process has been determinated. Ordinary and quickly hardening Portland cements absorb H2O and CO2 more than white cement – about 70 % – 75 % and 30 % – 38 % per month of innitial mass, respectively. White cement is more resistant to prehydration and carbonation, because it contains less C3A, C4AF and alkali, characterized initial activity. Dry mixes with white cement, although slower, but still worse after stored. Influence of routine dry mortar mixes ingredients and additives (methyl cellulose, pigments, sand and lime on prehydration properties of the mixes for finishing purpose is not substantial. Significant positive influence comes from the addition of fatty acid salts (zinc stearate or sodium oleate. The dry cement mixes for finishing purpose has been recomended to hydrophobisate with one of these additives, adding about 1 % by weight of cement during preducing mixes. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5243

  14. Ageing of Dry Cement Mixes for Finishing Purposes

    Directory of Open Access Journals (Sweden)

    Bronius VEKTARIS

    2013-09-01

    Full Text Available Dry building mixes, stored in the air, absorb water vapor and CO2 gas and ageing because properties of binding materials, mostly Portland cement, deteriorate after its prehydration and carbonation. In this paper the ageing singularities of dry cement mixes for finishing purposes and additives for retarding this process has been determinated. Ordinary and quickly hardening Portland cements absorb H2O and CO2 more than white cement – about 70 % – 75 % and 30 % – 38 % per month of innitial mass, respectively. White cement is more resistant to prehydration and carbonation, because it contains less C3A, C4AF and alkali, characterized initial activity. Dry mixes with white cement, although slower, but still worse after stored. Influence of routine dry mortar mixes ingredients and additives (methyl cellulose, pigments, sand and lime on prehydration properties of the mixes for finishing purpose is not substantial. Significant positive influence comes from the addition of fatty acid salts (zinc stearate or sodium oleate. The dry cement mixes for finishing purpose has been recomended to hydrophobisate with one of these additives, adding about 1 % by weight of cement during preducing mixes. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5243

  15. Charged Nanowire-Directed Growth of Amorphous Calcium Carbonate Nanosheets in a Mixed Solvent for Biomimetic Composite Films.

    Science.gov (United States)

    Liu, Yangyi; Liu, Lei; Chen, Si-Ming; Chang, Fu-Jia; Mao, Li-Bo; Gao, Huai-Ling; Ma, Tao; Yu, Shu-Hong

    2018-04-19

    Bio-inspired mineralization is an effective way for fabricating complicated inorganic materials, which inspires us to develop new methods to synthesize materials with fascinating properties. In this article, we report that the charged tellurium nanowires (TeNWs) can be used as bio-macromolecule analogues to direct the formation of amorphous calcium carbonate (ACC) nanosheets (ACCNs) in a mixed solvent. The effects of surface charges and the concentration of the TeNWs on the formation of ACCNs have been investigated. Particularly, the produced ACCNs can be functionalized by Fe3O4 nanoparticles to produce magnetic ACC/Fe3O4 hybrid nanosheets, which can be used to construct ACC/Fe3O4 composite films through a self-evaporation process. Moreover, sodium alginate-ACC nanocomposite films with remarkable toughness and good transmittance can also be fabricated by using such ACCNs as nanoscale building blocks. This mineralization approach in a mixed solvent using charged tellurium nanowires as bio-macromolecule analogues provides a new way for the synthesis of ACCNs, which can be used as nanoscale building blocks for fabrication of biomimetic composite films.

  16. Enhanced light absorption due to the mixing state of black carbon in fresh biomass burning emissions

    Science.gov (United States)

    Wang, Qiyuan; Cao, Junji; Han, Yongming; Tian, Jie; Zhang, Yue; Pongpiachan, Siwatt; Zhang, Yonggang; Li, Li; Niu, Xinyi; Shen, Zhenxing; Zhao, Zhuzi; Tipmanee, Danai; Bunsomboonsakul, Suratta; Chen, Yang; Sun, Jian

    2018-05-01

    A lack of information on the radiative effects of refractory black carbon (rBC) emitted from biomass burning is a significant gap in our understanding of climate change. A custom-made combustion chamber was used to simulate the open burning of crop residues and investigate the impacts of rBC size and mixing state on the particles' optical properties. Average rBC mass median diameters ranged from 141 to 162 nm for the rBC produced from different types of crop residues. The number fraction of thickly-coated rBC varied from 53 to 64%, suggesting that a majority of the freshly emitted rBC were internally mixed. By comparing the result of observed mass absorption cross-section to that calculated with Mie theory, large light absorption enhancement factors (1.7-1.9) were found for coated particles relative to uncoated cores. These effects were strongly positively correlated with the percentage of coated particles but independent of rBC core size. We suggest that rBC from open biomass burning may have strong impact on air pollution and radiative forcing immediately after their production.

  17. Carbon molecular sieve membrane from a microporous spirobisindane-based polyimide precursor with enhanced ethylene/ethane mixed-gas selectivity

    KAUST Repository

    Salinas, Octavio

    2017-01-13

    Ethylene is typically produced by steam cracking of various hydrocarbon feedstocks. The gaseous products are then separated in a demethanizer followed by a deethanizer unit and finally sent to a C splitter for the final purification step. Cryogenic distillation of ethylene from ethane is the most energy-intensive unit operation process in the chemical industry. Therefore, the development of more energy-efficient processes for ethylene purification is highly desirable. Membrane-based separation has been proposed as an alternative option for replacement or debottlenecking of C splitters but current polymer membrane materials exhibit insufficient mixed-gas CH/CH selectivity (<7) to be technically and economically attractive. In this work, a highly selective carbon molecular sieve (CMS) membrane derived from a novel spirobisindane-based polyimide of intrinsic microporosity (PIM-6FDA) was developed and characterized. PIM-6FDA showed a single-stage degradation process under an inert nitrogen atmosphere which commenced at ∼480 °C. The CMS formed by pyrolysis at 800 °C had a diffusion/size-sieving-controlled morphology with a mixed-gas (50% CH/50% CH) ethylene/ethane selectivity of 15.6 at 20 bar feed pressure at 35 °C. The mixed-gas ethylene/ethane selectivity is the highest reported value for CMS-type membranes to date.

  18. Carbon payments and low-cost conservation.

    Science.gov (United States)

    Crossman, Neville D; Bryan, Brett A; Summers, David M

    2011-08-01

    A price on carbon is expected to generate demand for carbon offset schemes. This demand could drive investment in tree-based monocultures that provide higher carbon yields than diverse plantings of native tree and shrub species, which sequester less carbon but provide greater variation in vegetation structure and composition. Economic instruments such as species conservation banking, the creation and trading of credits that represent biological-diversity values on private land, could close the financial gap between monocultures and more diverse plantings by providing payments to individuals who plant diverse species in locations that contribute to conservation and restoration goals. We studied a highly modified agricultural system in southern Australia that is typical of many temperate agriculture zones globally (i.e., has a high proportion of endangered species, high levels of habitat fragmentation, and presence of non-native species). We quantified the economic returns from agriculture and from carbon plantings (monoculture and mixed tree and shrubs) under six carbon-price scenarios. We also identified high-priority locations for restoration of cleared landscapes with mixed tree and shrub carbon plantings. Depending on the price of carbon, direct annual payments to landowners of AU$7/ha/year to $125/ha/year (US$6-120/ha/year) may be sufficient to augment economic returns from a carbon market and encourage tree plantings that contribute more to the restoration of natural systems and endangered species habitats than monocultures. Thus, areas of high priority for conservation and restoration may be restored relatively cheaply in the presence of a carbon market. Overall, however, less carbon is sequestered by mixed native tree and shrub plantings. © 2011 Society for Conservation Biology.

  19. Some problems associated with the analysis and interpretation of mixed carbonate and quartz beach sands, illustrated by examples from North-West Ireland

    Science.gov (United States)

    Carter, R. W. G.

    1982-09-01

    Mixes of carbonate and quartz sands, which are commonly encountered in Recent coastal sediments, require careful analysis if they are to be correctly interpreted. Grain-size data fall into multimodal or segmented zig-zag distributions which may require some kind of component separation if they are to be summarised by conventional statistics, and before they can be assigned to a particular hydrodynamic depositional process or environment. Unfortunately, separation techniques are only spasmodically applied, usually without due regard to the consequences. Such artificially filtered or truncated distributions are of little subsequent use. Using a range of samples from two beaches in NW Ireland, where carbonate proportions range from nearly zero to over sixty percent, the interrelationships of the two dominant components were examined. Where only a small carbonate proportion is incorporated into a large quartz one, predictable modifications of the size-curve are apparent. However, the components are more independent if mixtures are near equal. The occurrence of a number of distinctive combinations of simple straight lines and complex zig-zag curves probably reflects the relatively dynamic nature of the carbonate fraction.

  20. Effects of internal mixing and aggregate morphology on optical properties of black carbon using a discrete dipole approximation model

    Directory of Open Access Journals (Sweden)

    B. V. Scarnato

    2013-05-01

    Full Text Available According to recent studies, internal mixing of black carbon (BC with other aerosol materials in the atmosphere alters its aggregate shape, absorption of solar radiation, and radiative forcing. These mixing state effects are not yet fully understood. In this study, we characterize the morphology and mixing state of bare BC and BC internally mixed with sodium chloride (NaCl using electron microscopy and examine the sensitivity of optical properties to BC mixing state and aggregate morphology using a discrete dipole approximation model (DDSCAT. DDSCAT is flexible in simulating the geometry and refractive index of particle aggregates. DDSCAT predicts a higher mass absorption coefficient (MAC, lower single scattering albedo (SSA, and higher absorption Angstrom exponent (AAE for bare BC aggregates that are lacy rather than compact. Predicted values of SSA at 550 nm range between 0.16 and 0.27 for lacy and compact aggregates, respectively, in agreement with reported experimental values of 0.25 ± 0.05. The variation in absorption with wavelength does not adhere precisely to a power law relationship over the 200 to 1000 nm range. Consequently, AAE values depend on the wavelength region over which they are computed. The MAC of BC (averaged over the 200–1000 nm range is amplified when internally mixed with NaCl (100–300 nm in radius by factors ranging from 1.0 for lacy BC aggregates partially immersed in NaCl to 2.2 for compact BC aggregates fully immersed in NaCl. The SSA of BC internally mixed with NaCl is higher than for bare BC and increases with the embedding in the NaCl. Internally mixed BC SSA values decrease in the 200–400 nm wavelength range, a feature also common to the optical properties of dust and organics. Linear polarization features are also predicted in DDSCAT and are dependent on particle size and morphology. This study shows that DDSCAT predicts complex morphology and mixing state dependent aerosol optical properties that have

  1. Evaluation of carbon storage in soil and plant biomass of primary ...

    African Journals Online (AJOL)

    Carbon sequestration in a forest ecosystem is an important determinant of the local and regional carbon stock. This study monitored forest types and carbon storage in both biomass and soil within primary mixed deciduous forests (PMDF) and secondary mixed deciduous forests (SMDF). One study plot measuring 50 x 50 m ...

  2. Ambient black carbon particle hygroscopic properties controlled by mixing state and composition

    Directory of Open Access Journals (Sweden)

    D. Liu

    2013-02-01

    Full Text Available The wet removal of black carbon aerosol (BC in the atmosphere is a crucial factor in determining its atmospheric lifetime and thereby the vertical and horizontal distributions, dispersion on local and regional scales, and the direct, semi-direct and indirect radiative forcing effects. The in-cloud scavenging and wet deposition rate of freshly emitted hydrophobic BC will be increased on acquisition of more-hydrophilic components by coagulation or coating processes. The lifetime of BC is still subject to considerable uncertainty for most of the model inputs, which is largely due to the insufficient constraints on the BC hydrophobic-to-hydrophilic conversion process from observational field data. This study was conducted at a site along UK North Norfolk coastline, where the BC particles were transported from different regions within Western Europe. A hygroscopicity tandem differential mobility analyser (HTDMA was coupled with a single particle soot photometer (SP2 to measure the hygroscopic properties of BC particles and associated mixing state in real time. In addition, a Soot Particle AMS (SP-AMS measured the chemical compositions of additional material associated with BC particles. The ensemble of BC particles persistently contained a less-hygroscopic mode at a growth factor (gf of around 1.05 at 90% RH (dry diameter 163 nm. Importantly, a more-hygroscopic mode of BC particles was observed throughout the experiment, the gf of these BC particles extended up to ~1.4–1.6 with the minimum between this and the less hygroscopic mode at a gf ~1.25, or equivalent effective hygroscopicity parameter κ ~0.1. The gf of BC particles (gfBC was highly influenced by the composition of associated soluble material: increases of gfBC were associated with secondary inorganic components, and these increases were more pronounced when ammonium nitrate was in the BC particles; however the presence of secondary organic matter suppressed

  3. Chloride pyrometallurgy of uranium ore. 2. Selective extraction of uranium using the mixed gas of chlorine and oxygen in the presence of activated carbon

    International Nuclear Information System (INIS)

    Taki, Tomihiro; Komoto, Shigetoshi; Otomura, Keiichiro; Takenaka, Toshihide; Sato, Nobuaki; Fujino, Takeo.

    1996-01-01

    Selective extraction of uranium from a phosphate ore was studied by using the mixed gas of Cl 2 and O 2 . On heating the ore and carbon mixture in Cl 2 , the volatilized chloride of uranium is accompanied by iron, aluminum, phosphorus and silicon chlorides. The addition of O 2 gas effectively lowered the volatilization ratios of aluminum, phosphorus and silicon. The ratio decreased with increasing oxygen flow rate up to 50 ml/min at 1,223 K (Cl 2 : 100 ml/min, O 2 +N 2 : 400 ml/min). The volatilization ratio of uranium was almost unchanged at 90% up to 50 ml/min O 2 (carbon amount: 15 wt%). The effect of the other parameters, i.e. Cl 2 flow rate, carbon amount, reaction temperature and time was examined. (author)

  4. Anthropogenic Forcing of Carbonate and Organic Carbon Preservation in Marine Sediments.

    Science.gov (United States)

    Keil, Richard

    2017-01-03

    Carbon preservation in marine sediments, supplemented by that in large lakes, is the primary mechanism that moves carbon from the active surficial carbon cycle to the slower geologic carbon cycle. Preservation rates are low relative to the rates at which carbon moves between surface pools, which has led to the preservation term largely being ignored when evaluating anthropogenic forcing of the global carbon cycle. However, a variety of anthropogenic drivers-including ocean warming, deoxygenation, and acidification, as well as human-induced changes in sediment delivery to the ocean and mixing and irrigation of continental margin sediments-all work to decrease the already small carbon preservation term. These drivers affect the cycling of both carbonate and organic carbon in the ocean. The overall effect of anthropogenic forcing in the modern ocean is to decrease delivery of carbon to sediments, increase sedimentary dissolution and remineralization, and subsequently decrease overall carbon preservation.

  5. Properties of PP/MWCNT-COOH /PP composites made by melt mixing versus solution cast /melt mixing methods

    International Nuclear Information System (INIS)

    Reinholds, I; Roja, Z; Zicans, J; Meri, R Merijs; Bitenieks, J

    2015-01-01

    An approach on improvement of the properties of polypropylene / carbon nanotube (PP/CNT) composites is reported. PP blend compositions with carboxylic acid functionalized multi-walled carbon nanotubes (MWCNT-COOH) at filler content 1.0 wt.% were researched. One part of the composites was manufactured by direct thermoplastic mixing PP with the filler, but the other one was made from solution casted masterbatch with the following thermoplastic mixing. An increase of mechanical properties (Young's modulus, storage modulus and tensile strength), compared to an increase of glass transition temperature indicated a reinforcement effect of CNTs on PP matrix, determined from the tensile tests and differential mechanical analysis (DMA), while the elongation was reduced, compared to PP matrix. By differential scanning calorimetry (DSC) analysis, the effect of nanofiller on the reorganization of PP crystallites was observed. A noticeable enhanced effect on increase of the crystallization temperature was indicated for masterbatch manufactured composite. An increase of thermal stability was also observed, compared to pristine PP and the composite made by direct thermoplastic mixing PP with the filler

  6. Effect of doping of multi-walled carbon nanotubes on phenolic based carbon fiber reinforced nanocomposites

    International Nuclear Information System (INIS)

    Saeed, Sadaf; Hakeem, Saira; Faheem, Muhammad; Alvi, Rashid Ahmed; Farooq, Khawar; Hussain, Syed Tajammul; Ahmad, Shahid Nisar

    2013-01-01

    We report on the effect of multi-walled carbon nanotubes (MWCNTs) on different properties of phenolic resin. A low content of MWCNTs (∼ 0.05 wt%) was mixed in phenolic resin and a stable dispersion was achieved by ultrasonication, followed by melt mixing. After curing the characterization of these composites was done by using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Fourier transform infra-red spectroscopy (FTIR). The thermal and ablative properties of carbon fiber reinforced MWCNTs-phenolic nanocomposites were also studied. The addition of MWCNTs showed improvement in thermal stability and ablation properties.

  7. An 8-year, high-resolution reanalysis of atmospheric carbon dioxide mixing ratios based on OCO-2 and GOSAT-ACOS retrievals

    Science.gov (United States)

    Weir, B.; Chatterjee, A.; Ott, L. E.; Pawson, S.

    2017-12-01

    This talk presents an overview of results from the GEOS-Carb reanalysis of retrievals of average-column carbon dioxide (XCO2) from the Orbiting Carbon Observatory 2 (OCO-2) and Greenhouse Gases Observing Satellite (GOSAT) satellite missions. The reanalysis is a Level 3 (L3) product: a collection of 3D fields of carbon dioxide (CO2) mixing ratios every 6 hours beginning in April 2009 going until the present on a grid with a 0.5 degree horizontal resolution and 72 vertical levels from the surface to 0.01 hPa. Using an assimilation methodology based on the Goddard Earth Observing System (GEOS) atmospheric data assimilation system (ADAS), the L3 fields are weighted averages of the two satellite retrievals and predictions from the GEOS general circulation model driven by assimilated meteorology from the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2). In places and times where there are a dense number of soundings, the observations dominate the predicted mixing ratios, while the model is used to fill in locations with fewer soundings, e.g., high latitudes and the Amazon. Blending the satellite observations with model predictions has at least two notable benefits. First, it provides a bridge for evaluating the satellite retrievals and their uncertainties against a heterogeneous collection of observations including those from surface sites, towers, aircraft, and soundings from the Total Carbon Column Observing Network (TCCON). Extensive evaluations of the L3 reanalysis clearly demonstrate both the strength and the deficiency of the satellite retrievals. Second, it is possible to estimate variables from the reanalysis without introducing bias due to spatiotemporal variability in sounding coverage. For example, the assimilated product provides robust estimates of the monthly CO2 global growth rate. These monthly growth rate estimates show significant differences from estimates based on in situ observations, which have sparse coverage

  8. Optimization Forest Thinning Measures for Carbon Budget in a Mixed Pine-Oak Stand of the Qingling Mountains, China: A Case Study

    Directory of Open Access Journals (Sweden)

    Lin Hou

    2016-11-01

    Full Text Available Forest thinning is a silviculture treatment for sustainable forest management. It may promote growth of the remaining individuals by decreasing stand density, reducing competition, and increasing light and nutrient availability to increase carbon sequestration in the forest ecosystem. However, the action also increases carbon loss simultaneously by reducing carbon and other nutrient inputs as well as exacerbating soil CO2 efflux. To achieve a maximum forest carbon budget, the central composite design with two independent variables (thinning intensity and thinning residual removal rate was explored in a natural pine-oak mixed stand in the Qinling Mountains, China. The net primary productivity of living trees was estimated and soil CO2 efflux was stimulated by the Yasso07 model. Based on two years observation, the preliminary results indicated the following. Evidently chemical compounds of the litter of the tree species affected soil CO2 efflux stimulation. The thinning residual removal rate had a larger effect than thinning intensity on the net ecosystem productivity. When the selective thinning intensity and residual removal rate was 12.59% and 66.62% concurrently, the net ecosystem productivity reached its maximum 53.93 t·ha−1·year−1. The lower thinning intensity and higher thinning residual removal rated benefited the net ecosystem productivity.

  9. Mixed bi-material electrodes based on LiMn2O4 and activated carbon for hybrid electrochemical energy storage devices

    International Nuclear Information System (INIS)

    Cericola, Dario; Novak, Petr; Wokaun, Alexander; Koetz, Ruediger

    2011-01-01

    Highlights: → Bi-material electrodes for electrochemical hybrid devices were characterized. → Bi-material electrodes have higher specific charge than capacitor electrodes. → Bi-material electrodes have better rate capability than battery electrodes. → Bi-material systems outperform batteries and capacitors in pulsed applications. - Abstract: The performance of mixed bi-material electrodes composed of the battery material, LiMn 2 O 4 , and the electrochemical capacitor material, activated carbon, for hybrid electrochemical energy storage devices is investigated by galvanostatic charge/discharge and pulsed discharge experiments. Both, a high and a low conductivity lithium-containing electrolyte are used. The specific charge of the bi-material electrode is the linear combination of the specific charges of LiMn 2 O 4 and activated carbon according to the electrode composition at low discharge rates. Thus, the specific charge of the bi-material electrode falls between the specific charge of the activated carbon electrode and the LiMn 2 O 4 battery electrode. The bi-material electrodes have better rate capability than the LiMn 2 O 4 battery electrode. For high current pulsed applications the bi-material electrodes typically outperform both the battery and the capacitor electrode.

  10. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Energy Technology Data Exchange (ETDEWEB)

    Byamba-Ochir, Narandalai [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of); Shim, Wang Geun [Department of Polymer Science and Engineering, Sunchon National University, 255 Jungang-Ro, Suncheon, Jeollanam-Do 57922 (Korea, Republic of); Balathanigaimani, M.S., E-mail: msbala@rgipt.ac.in [Department of Chemical Engineering, Rajiv Gandhi Institute of Petroleum Technology, Ratapur Chowk, Rae Bareli, 229316 Uttar Pradesh (India); Moon, Hee, E-mail: hmoon@jnu.ac.kr [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of)

    2016-08-30

    Highlights: • Highly porous carbon materials from Mongolian anthracite by chemical activation. • Cheaper and eco-friendly activation process has been employed. • Activated carbons with graphitic structure and energetically heterogeneous surface. • Surface hydrophobicity and porosity of the activated carbons can be controlled. - Abstract: Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816–2063 m{sup 2}/g and of 0.55–1.61 cm{sup 3}/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  11. Tough ceramic coatings: Carbon nanotube reinforced silica sol-gel

    Science.gov (United States)

    López, A. J.; Rico, A.; Rodríguez, J.; Rams, J.

    2010-08-01

    Silica coatings reinforced with carbon nanotubes were produced via sol-gel route using two mixing techniques of the sol-gel precursors, mechanical and ultrasonic mixing, and dip-coating as deposition process on magnesium alloy substrates. Effective incorporation and distribution of 0.1 wt.% of carbon nanotubes in the amorphous silica matrix of the coatings were achieved using both techniques. Fabrication procedure determines the morphological aspects of the coating. Only mechanical mixing process produced coatings dense and free of defects. Nanoindentation technique was used to examine the influence of the fabrication process in the mechanical features of the final coatings, i.e. indentation fracture toughness, Young's modulus and hardness. A maximum toughening effect of about 24% was achieved in silica coatings reinforced with carbon nanotubes produced by the mechanical mixing route. Scanning electron microscopy investigation revealed that the toughening of these reinforced coatings was mainly due to bridging effect of the reinforcement.

  12. Surface Complexation Modeling of Calcite Zeta Potential Measurement in Mixed Brines for Carbonate Wettability Characterization

    Science.gov (United States)

    Song, J.; Zeng, Y.; Biswal, S. L.; Hirasaki, G. J.

    2017-12-01

    We presents zeta potential measurements and surface complexation modeling (SCM) of synthetic calcite in various conditions. The systematic zeta potential measurement and the proposed SCM provide insight into the role of four potential determining cations (Mg2+, SO42- , Ca2+ and CO32-) and CO2 partial pressure in calcite surface charge formation and facilitate the revealing of calcite wettability alteration induced by brines with designed ionic composition ("smart water"). Brines with varying potential determining ions (PDI) concentration in two different CO2 partial pressure (PCO2) are investigated in experiments. Then, a double layer SCM is developed to model the zeta potential measurements. Moreover, we propose a definition for contribution of charged surface species and quantitatively analyze the variation of charged species contribution when changing brine composition. After showing our model can accurately predict calcite zeta potential in brines containing mixed PDIs, we apply it to predict zeta potential in ultra-low and pressurized CO2 environments for potential applications in carbonate enhanced oil recovery including miscible CO2 flooding and CO2 sequestration in carbonate reservoirs. Model prediction reveals that pure calcite surface will be positively charged in all investigated brines in pressurized CO2 environment (>1atm). Moreover, the sensitivity of calcite zeta potential to CO2 partial pressure in the various brine is found to be in the sequence of Na2CO3 > Na2SO4 > NaCl > MgCl2 > CaCl2 (Ionic strength=0.1M).

  13. Substrate Effect on Carbon/Ceramic Mixed Matrix Membrane Prepared by a Vacuum-Assisted Method for Desalination

    Directory of Open Access Journals (Sweden)

    Yingjun Song

    2018-05-01

    Full Text Available This work investigates the effect of various membrane substrates and coating conditions on the formation of carbon/ceramic mixed matrix membranes for desalination application. The substrates were impregnated with phenolic resin via a vacuum-assisted method followed by carbonization under an inert gas. Substrates with pore sizes of 100 nm required a single impregnation step only, where short vacuum times (<120 s resulted in low quality membranes with defects. For vacuum times of ≥120 s, high quality membranes with homogeneous impregnation were prepared leading to high salt rejection (>90% and high water fluxes (up to 25 L m−2 h−1. The increase in water flux as a function of the vacuum time confirms the vacuum etching effect resulting from the vacuum-assisted method. Substrates with pore sizes of 140 nm required two impregnation steps. These pores were too large for the ceramic inter-particle space to be filled with phenolic resin via a single step. In the second impregnation step, increasing the concentration of the phenolic resin resulted in membranes with lower water fluxes. These results indicate that thicker films were formed by increasing the phenolic resin concentration. In the case of substrates with pores of 600 nm, these pores were too large and inter-particle space filling with phenolic resin was not attained.

  14. Thin TaC layer produced by ion mixing

    DEFF Research Database (Denmark)

    Barna, Árpád; Kotis, László; Pécz, Béla

    2012-01-01

    in strongly asymmetric ion mixing; the carbon was readily transported to the Ta layer, while the reverse process was much weaker. Because of the asymmetrical transport the C/TaC interface remained sharp independently from the applied fluence. The carbon transported to the Ta layer formed Ta......Ion-beam mixing in C/Ta layered systems was investigated. C 8nm/Ta 12nm and C 20nm/Ta 19nm/C 20nm layer systems were irradiated by Ga+ ions of energy in the range of 2–30keV. In case of the 8nm and 20nm thick C cover layers applying 5–8keV and 20–30keV Ga+ ion energy, respectively resulted...

  15. Mixed quantum-classical simulations of the vibrational relaxation of photolyzed carbon monoxide in a hemoprotein

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, Alexander, E-mail: schubert@irsamc.ups-tlse.fr; Meier, Christoph [Laboratoire Collisions Agrégats et Réactivité, IRSAMC, UMR CNRS 5589, Université Paul Sabatier, 31062 Toulouse (France); Falvo, Cyril [Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay (France)

    2016-08-07

    We present mixed quantum-classical simulations on relaxation and dephasing of vibrationally excited carbon monoxide within a protein environment. The methodology is based on a vibrational surface hopping approach treating the vibrational states of CO quantum mechanically, while all remaining degrees of freedom are described by means of classical molecular dynamics. The CO vibrational states form the “surfaces” for the classical trajectories of protein and solvent atoms. In return, environmentally induced non-adiabatic couplings between these states cause transitions describing the vibrational relaxation from first principles. The molecular dynamics simulation yields a detailed atomistic picture of the energy relaxation pathways, taking the molecular structure and dynamics of the protein and its solvent fully into account. Using the ultrafast photolysis of CO in the hemoprotein FixL as an example, we study the relaxation of vibrationally excited CO and evaluate the role of each of the FixL residues forming the heme pocket.

  16. Mixed plasma-facing materials research at INEEL

    International Nuclear Information System (INIS)

    Anderl, R.A.; Longhurst, G.R.; Pawelko, R.J.

    2001-01-01

    Mixed-materials research at the Idaho National Engineering and Environmental Laboratory (INEEL) has focused on Be-C and W-C systems. The purpose of this work was to investigate hydrogen isotope retention in these systems. Plasma-mixed material layers using carbon coated Be and W specimens that were heat-treated and tungsten carbide specimens prepared by chemical vapor deposition (CVD) were simulated. Hydrogen isotope retention was investigated by means of thermal desorption spectroscopy (TDS) measurements on deuterium implanted samples

  17. Growth of microbial mixed cultures under anaerobic, alkaline conditions

    International Nuclear Information System (INIS)

    Wenk, M.

    1993-09-01

    Cement and concrete are the most important engineered barrier materials in a repository for low- and intermediate-level waste and thus represent the most significant component of the total disposal inventory. Based on the chemical composition of the concrete used in the repository and the groundwater fluxes in the modelled host rock, it is to be expected that the pH in the near vicinity of the repository could exceed a value of 10.5 for more than a million years. The groundwater in the repository environment also has a limited carbon concentration. Since microorganisms will be present in a repository and can even find suitable living conditions within the waste itself, investigations were carried out in order to establish the extent to which microbial activity is possible under the extreme conditions of the repository near-field. For the investigations, alkalophilic cultures were enriched from samples from alkaline habitats and from Valanginian Marl. Anaerobic bacteria with fermentative, sulfate-reducing and methanogenic metabolism were selected. The growth and activity of the mixed cultures were studied under alkaline conditions and the dependence on pH and carbon concentration determined. All the mixed cultures investigated are alkalophilic. The optimum growth range for the cultures is between pH 9.0 and pH 10.0. The activity limit for the fermentative mixed culture is at pH 12, for the sulfate-reducers at pH 11 and for the methanogens at pH 10.5. Given the limited supply of carbon, the mixed cultures can only grow under slightly alkaline conditions. Only the fermentative cultures are capable of surviving with limited carbon supply at pH 13. (author) 24 figs., 18 tabs., 101 refs

  18. The chlorination kinetics of zirconium dioxide mixed with carbon black

    International Nuclear Information System (INIS)

    Movahedian, A.; Raygan, Sh.; Pourabdoli, M.

    2011-01-01

    In this research, the effects of chlorine gas at different chlorine partial pressures and carbon concentrations on the carbochlorination of zirconia were studied. It was found that in briquettes containing 18.7 %wt carbon, in a chlorine partial pressure range of 0.25-0.75 atm and for a reacted fraction of less than 0.7, the chemical reaction model was dominant for the carbochlorination process of zirconia. The order of reaction into chlorine gas (n) in this situation was 0.57. Moreover, the best weight ratio of carbon to zirconia was 40/60. In this case, the activation energy of the reaction was 209.9 kJ mol -1 in a temperature range of 1023-1223 K, and the dominant model was the chemical reaction model.

  19. The research of a method for determination of total carbon, combination carbon and free carbon in beryllium metal

    International Nuclear Information System (INIS)

    Yang Xingzhong; Zhu Xiaohong

    1996-02-01

    A method for determination of total carbon, combination carbon and free carbon in beryllium metal with LECO CS-344 carbon/sulphur determinant has been studied. Tungsten-copper mixed pellets are used as flux to the determination of total carbon. Ratio of weight of the flux to the sample is greater than 20:1. Good analytical results are got. By this method the relative standard deviation is <10% when the content of total carbon in the range of 0.050%∼0.080% in beryllium. A standard steel sample of carbon is added into beryllium, the recoveries are 94%∼106%. For determination of free carbon, the sample are decomposed with 3 mol/L HCl, filtered and followed determination. By this method the relative standard deviation is ≤10% when the content of free carbon in the range of 0.006%∼0.020% in beryllium. the balance of total carbon and free carbon is equal to combination carbon. The method is used to determine the sample of content of total carbon in the range of 0.050%∼1.00%, free carbon in the range of 0.006%∼0.500% in metal beryllium. (6 refs., 1 fig., 13 tabs.)

  20. In situ enhanced soil mixing. Innovative technology summary report

    International Nuclear Information System (INIS)

    1996-02-01

    In Situ Enhanced Soil Mixing (ISESM) is a treatment technology that has been demonstrated and deployed to remediate soils contaminated with volatile organic compounds (VOCs). The technology has been developed by industry and has been demonstrated with the assistance of the U.S. Department of Energy's Office of Science and Technology and the Office of Environmental Restoration. The technology is particularly suited to shallow applications, above the water table, but can be used at greater depths. ISESM technologies demonstrated for this project include: (1) Soil mixing with vapor extraction combined with ambient air injection. [Contaminated soil is mixed with ambient air to vaporize volatile organic compounds (VOCs). The mixing auger is moved up and down to assist in removal of contaminated vapors. The vapors are collected in a shroud covering the treatment area and run through a treatment unit containing a carbon filter or a catalytic oxidation unit with a wet scrubber system and a high efficiency particulate air (HEPA) filter.] (2) soil mixing with vapor extraction combined with hot air injection [This process is the same as the ambient air injection except that hot air or steam is injected.] (3) soil mixing with hydrogen peroxide injection [Contaminated soil is mixed with ambient air that contains a mist of diluted hydrogen peroxide (H 2 O 2 ) solution. The H 2 O 2 solution chemically oxidizes the VOCs to carbon dioxide (CO 2 ) and water.] (4) soil mixing with grout injection for solidification/stabilization [Contaminated soil is mixed as a cement grout is injected under pressure to solidify and immobilize the contaminated soil in a concrete-like form.] The soils are mixed with a single-blade auger or with a combination of augers ranging in diameter from 3 to 12 feet

  1. Nano-engineered composites: interlayer carbon nanotubes effect

    Energy Technology Data Exchange (ETDEWEB)

    Carley, Glaucio, E-mail: carleyone@hotmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Geraldo, Viviany; Oliveira, Sergio de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica; Avila, Antonio Ferreira [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Fisica

    2013-11-01

    The concept of carbon nanotube interlayer was successfully introduced to carbon fiber/epoxy composites. This new hybrid laminated composites was characterized by Raman spectroscopy, X-ray diffraction, scanning electron microscopy and tensile tests. An increase on peak stress close to 85% was witnessed when CNTs interlayer with 206.30 mg was placed to carbon fiber/epoxy laminates. The failure mechanisms are associated to CNTs distribution between and around carbon fibers. These CNTs are also responsible for crack bridging formation and the increase on peak stress. Initial stiffness is strongly affected by the CNT interlayer, however, changes on stiffness is associated to changes on nano/micro-structure due to damage. Three different behaviors can be described, i.e. for interlayers with Almost-Equal-To 60 mg of CNT the failure mode is based on cracks between and around carbon fibers, while for interlayers with CNT contents between 136 mg and 185 mg cracks were spotted on fibers and inside the CNT/matrix mix. Finally, the third failure mechanism is based on carbon fiber breakage, as a strong interface between CNT/matrix mix and carbon fibers is observed. (author)

  2. Nano-engineered composites: interlayer carbon nanotubes effect

    International Nuclear Information System (INIS)

    Carley, Glaucio; Geraldo, Viviany; Oliveira, Sergio de; Avila, Antonio Ferreira

    2013-01-01

    The concept of carbon nanotube interlayer was successfully introduced to carbon fiber/epoxy composites. This new hybrid laminated composites was characterized by Raman spectroscopy, X-ray diffraction, scanning electron microscopy and tensile tests. An increase on peak stress close to 85% was witnessed when CNTs interlayer with 206.30 mg was placed to carbon fiber/epoxy laminates. The failure mechanisms are associated to CNTs distribution between and around carbon fibers. These CNTs are also responsible for crack bridging formation and the increase on peak stress. Initial stiffness is strongly affected by the CNT interlayer, however, changes on stiffness is associated to changes on nano/micro-structure due to damage. Three different behaviors can be described, i.e. for interlayers with ≈ 60 mg of CNT the failure mode is based on cracks between and around carbon fibers, while for interlayers with CNT contents between 136 mg and 185 mg cracks were spotted on fibers and inside the CNT/matrix mix. Finally, the third failure mechanism is based on carbon fiber breakage, as a strong interface between CNT/matrix mix and carbon fibers is observed. (author)

  3. Tree Stress and Mortality from Emerald Ash Borer Does Not Systematically Alter Short-Term Soil Carbon Flux in a Mixed Northeastern U.S. Forest

    Directory of Open Access Journals (Sweden)

    Jaclyn Hatala Matthes

    2018-01-01

    Full Text Available Invasive insect pests are a common disturbance in temperate forests, but their effects on belowground processes in these ecosystems are poorly understood. This study examined how aboveground disturbance might impact short-term soil carbon flux in a forest impacted by emerald ash borer (Agrilus planipennis Fairmaire in central New Hampshire, USA. We anticipated changes to soil moisture and temperature resulting from tree mortality caused by emerald ash borer, with subsequent effects on rates of soil respiration and methane oxidation. We measured carbon dioxide emissions and methane uptake beneath trees before, during, and after infestation by emerald ash borer. In our study, emerald ash borer damage to nearby trees did not alter soil microclimate nor soil carbon fluxes. While surprising, the lack of change in soil microclimate conditions may have been a result of the sandy, well-drained soil in our study area and the diffuse spatial distribution of canopy ash trees and subsequent canopy light gaps after tree mortality. Overall, our results indicate that short-term changes in soil carbon flux following insect disturbances may be minimal, particularly in forests with well-drained soils and a mixed-species canopy.

  4. Mixed Waste Treatment Using the ChemChar Thermolytic Detoxification Technique

    International Nuclear Information System (INIS)

    Kuchynka, D.J.

    1997-01-01

    This R and D program addresses the treatment of mixed waste employing the ChemChar Thermolytic Detoxification process. Surrogate mixed waste streams will be treated in a four inch diameter, continuous feed, adiabatic reactor with the goal of meeting all regulatory treatment levels for the contaminants in the surrogates with the concomitant production of contaminant free by-products. Successful completion of this program will show that organic contaminants in mixed waste surrogates will be converted to a clean, energy rich synthesis gas capable of being used, without further processing, for power or heat generation. The inorganic components in the surrogates will be found to be adsorbed on a macroporous coal char activated carbon substrate which is mixed with the waste prior to treatment. These contaminants include radioactive metal surrogate species, RCRA hazardous metals and any acid gases formed during the treatment process. The program has three main tasks that will be performed to meet the above objectives. The first task is the design and construction of the four inch reactor at Mirage Systems in Sunnyvale, CA. The second task is production and procurement of the activated carbon char employed in the ChemChartest runs and identification of two surrogate mixed wastes. The last task is testing and operation of the reactor on char/surrogate waste mixtures to be performed at the University of Missouri. The deliverables for the project are a Design Review Report, Operational Test Plan, Topical Report and Final Report. This report contains only the results of the design and construction carbon production-surrogate waste identification tasks.Treatment of the surrogate mixed wastes has just begun and will not be reported in this version of the Final Report. The latter will be reported in the final version of the Final Report

  5. Effect of Graphene Oxide Mixed Epoxy on Mechanical Properties of Carbon Fiber/Acrylonitrile-Butadiene-Styrene Composites.

    Science.gov (United States)

    Wang, Cuicui; Ge, Heyi; Ma, Xiaolong; Liu, Zhifang; Wang, Ting; Zhang, Jingyi

    2018-04-01

    In this study, the watersoluble epoxy resin was prepared via the ring-opening reaction between diethanolamine and epoxy resin. The modified resin mixed with graphene oxide (GO) as a sizing agent was coated onto carbon fiber (CF) and then the GO-CF reinforced acrylonitrile-butadienestyrene (ABS) composites were prepared. The influences of the different contents of GO on CF and CF/ABS composite were explored. The combination among epoxy, GO sheets and maleic anhydride grafted ABS (ABSMA) showed a synergistic effect on improving the properties of GO-CF and GO-CF/ABS composite. The GO-CF had higher single tensile strength than the commercial CF. The maximum ILSS of GO-CF/ABS composite obtained 19.2% improvement as compared with that of the commercial CF/ABS composite. Such multiscale enhancement method and the synergistic reinforced GO-CF/ABS composite show good prospective applications in many industry areas.

  6. Evaluating the Carbonation Resistance of Self Compacting Concrete made with Recycled Concrete Aggregates

    Directory of Open Access Journals (Sweden)

    S P Singh

    2016-07-01

    Full Text Available The paper presents the results of an investigation conducted to examine carbonation resistance of Self Compacting Concrete (SCC made with coarse Recycled Concrete Aggregates (RCA. In total, five SCC mixes were prepared by systematically replacing coarse Natural Aggregates (NA by RCA at 0, 25, 50, 75 and 100%. In order to measure the carbonation resistance of SCC made with RCA, accelerated carbonation tests were performed for 4 and 12 weeks of exposure to carbon dioxide. The carbonation resistance has been evaluated after curing periods of 28 and 90 days. In addition to this, the compressive strength of all the mixes was also obtained after 7, 28 and 90 days of curing and ultra-sonic pulse velocity tests (UPV were also conducted. The results indicate that with the increase in the content of RCA as replacement of NA, decrease in the carbonation resistance, compressive strength and UPV was observed for all SCC mixes. It has been observed that the SCC mixes containing low percentages of RCA (i.e. 25% as replacement of NA do not impart detrimental behaviour in the overall performance but higher replacement levels (>50% have been found to deteriorate the performance in terms of carbonation resistance, compressive strength and UPV.

  7. Rubber mixing process and its relationship with bound rubber and crosslink density

    Science.gov (United States)

    Hasan, A.; Rochmadi; Sulistyo, H.; Honggokusumo, S.

    2017-06-01

    This research studied the relationship between bound rubber and crosslink density based on rubber mixing process. Bound rubber was obtained after natural rubber was masticated and mixed with rubber chemicals and filler while crosslink density was collected after rubber compound was vulcanized. Four methods are used and each method refers to four ways of incorporating carbon black during mixing. The first method, after rubber was masticated for 5 minutes, the addition of rubber chemicals and filler was done simultaneously. Rubber was masticated for 1 minute and continued mixing of rubber chemicals and filler where mixing was different from first method. This was the second method. The third method was the same as the second method but the filler used N 660 while in the second method N 330. The last method is not the same as the first and second, the rubber is only masticated for 3 minutes and then mixed with filler and followed by rubber chemicals sequentially. The results showed that bound rubber and crosslink density were influenced by mixing and mastication process. Bound rubber dropped and crosslink density was relatively stable in the first three mixing methods for increasing carbon black at the beginning of the mixing process. Bound rubber and crosslink density stated opposite results in the fourth mixing method. The higher the bound rubber the lower the crosslink density. Without regard to mixing methods, there is a non-linear relationship between bound rubber formation and crosslink density determination

  8. Preparation, physical-chemical characterisation and cytocompatibility of calcium carbonate cements.

    Science.gov (United States)

    Combes, C; Miao, Baoji; Bareille, Reine; Rey, Christian

    2006-03-01

    The feasibility of calcium carbonate cements involving the recrystallisation of metastable calcium carbonate varieties has been demonstrated. Calcium carbonate cement compositions presented in this paper can be prepared straightforwardly by simply mixing water (liquid phase) with two calcium carbonate phases (solid phase) which can be easily obtained by precipitation. An original cement composition was obtained by mixing amorphous calcium carbonate and vaterite with an aqueous medium. The cement set and hardened within 2h at 37 degrees C in an atmosphere saturated with water and the final composition of the cement consisted mostly of aragonite. The hardened cement was microporous and showed poor mechanical properties. Cytotoxicity tests revealed excellent cytocompatibility of calcium carbonate cement compositions. Calcium carbonates with a higher solubility than the apatite formed for most of the marketed calcium phosphate cements might be of interest to increase biomedical cement resorption rates and to favour its replacement by bone tissue.

  9. Bioconversion of mixed volatile fatty acids into microbial lipids by Cryptococcus curvatus ATCC 20509.

    Science.gov (United States)

    Liu, Jia; Yuan, Ming; Liu, Jia-Nan; Huang, Xiang-Feng

    2017-10-01

    The oleaginous yeast Cryptococcus curvatus ATCC 20509 can use 5-40g/L of acetic, propionic, or butyric acid as sole carbon source to produce lipids. High concentrations (30g/L) of mixed volatile fatty acids (VFAs) were used to cultivate C. curvatus to explore the effects of different ratios of mixed VFAs on lipid production and composition. When mixed VFAs (VFA ratio was 15:5:10) were used as carbon sources, the highest cell mass and lipid concentration were 8.68g/L and 4.93g/L, respectively, which were significantly higher than those when 30g/L of acetic acid was used as sole carbon source. The highest content and yield of odd-numbered fatty acids were 45.1% (VFA ratio was 0:15:15) and 1.62g/L (VFA ratio was 5:15:10), respectively. These results indicate that adjusting the composition ratios of mixed VFAs effectively improves microbial lipid synthesis and the yield of odd-numbered fatty acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Carbonation of ternary cementitious concrete systems containing fly ash and silica fume

    Directory of Open Access Journals (Sweden)

    Eehab Ahmed Badreldin Khalil

    2015-04-01

    Full Text Available Carbonation is quite a complex physical negative effect phenomenon on concrete especially in the ones containing ternary blends of Portland Cement, fly ash, and silica fume. Nine selected concrete mixtures were prepared with various water to cementitious materials’ ratios and various cementitious contents. The concrete mixtures were adapted in such a way to have the same workability and air content. The fresh concrete properties were kept near identical in slump, air content, and unit weight. The variation was in the hardened concrete mechanical properties of compression and tension strength. The carbonation phenomenon was studied for these mixes showing at which mixes of ternary cementitious content heavy carbonation attacks maybe produced. The main components of such mixes that do affect the carbonation process with time were presented.

  11. A gaseous measurement system for carbon-14 dioxide and carbon-14 methane: An analytical methodology to be applied in the evaluation of the carbon-14 dioxide and carbon-14 methane produced via microbial activity in volcanic tuff

    International Nuclear Information System (INIS)

    Dolan, M.M.

    1987-01-01

    The objectives of this study were to develop a gaseous measurement system for the carbon-14 dioxide and carbon-14 methane produced via microbial activity or geochemical action on leachate in tuff; to determine the trapping efficiency of the system for carbon-14 dioxide; to determine the trapping efficiency of the system for carbon-14 methane; to apply the experimentally determined factors regarding the system's trapping efficiency for carbon-14 dioxide and carbon-14 methane to a trapping algorithm to determine the activity of the carbon-14 dioxide and carbon-14 methane in a mixed sample; to determine the minimum detectable activity of the measurement process in picocuries per liter; and to determine the lower limit or detection of the measurement process in counts per minute

  12. Effects of carbon sources on the enrichment of halophilic polyhydroxyalkanoate-storing mixed microbial culture in an aerobic dynamic feeding process

    Science.gov (United States)

    Cui, You-Wei; Zhang, Hong-Yu; Lu, Peng-Fei; Peng, Yong-Zhen

    2016-08-01

    Microbial polyhydroxyalkanoate (PHA) production serves as a substitute for petroleum-based plastics. Enriching mixed microbial cultures (MMCs) with the capacity to store PHA is a key precursor for low-cost PHA production. This study investigated the impact of carbon types on enrichment outcomes. Three MMCs were separately fed by acetate sodium, glucose, and starch as an enriching carbon source, and were exposed to long-term aerobic dynamic feeding (ADF) periods. The PHA production capacity, kinetics and stoichiometry of the enrichments, the PHA composition, and the microbial diversity and community composition were explored to determine carbon and enrichment correlations. After 350-cycle enriching periods under feast-famine (F-F) regimes, the MMCs enriched by acetate sodium and glucose contained a maximum PHA content of 64.7% and 60.5% cell dry weight (CDW). The starch-enriched MMC only had 27.3% CDW of PHA. High-throughput sequencing revealed that non-PHA bacteria survived alongside PHA storing bacteria, even under severe F-F selective pressure. Genus of Pseudomonas and Stappia were the possible PHA accumulating bacteria in acetate-enriched MMC. Genus of Oceanicella, Piscicoccus and Vibrio were found as PHA accumulating bacteria in glucose-enriched MMC. Vibrio genus was the only PHA accumulating bacteria in starch-enriched MMC. The community diversity and composition were regulated by the substrate types.

  13. Mixed Matrix Composite Membranes Containing POSS Molecules for Carbon Dioxide Removal Application

    KAUST Repository

    Rini, Eki Listya

    2011-05-10

    CO2 removal by membrane processes is considerably potential for several applications such as natural gas and synthesis gas purification, enhanced oil recovery application, and carbon dioxide capture in combat against global warming. Dense polymeric membranes are commonly utilized for these type of gas separation applications. Nevertheless, the intrinsic properties of dense polymeric membranes, which commonly characterize by the low gas permeability versus high gas selectivity trade–off or vice versa, is less desirable. In order to meet the increased demand of CO2 removal, a strategy to improve the gas separation performance of a polymeric membrane is investigated in this study. With this regard, mixed matrix membranes in which inorganic non porous fillers are incorporated into a polymeric matrix were prepared to achieve the aforementioned objective. The mixed matrix membranes were prepared from Pebax® block copolymers and PEG POSS® molecules. These hybrid membranes were formed as both dense and multilayer composite membranes. The dense transparent membranes with well–dispersed fillers could be obtained by variation of the solvent mixture. The DSC analyses showed that incorporation of PEG POSS® into Pebax® matrix altered the thermal properties of the matrix. The multilayer composite membranes were then prepared from a PTMSP gutter layer deposited on a PAN porous support and an adjacent hybrid Pebax®/PEG POSS® as the top layer. These hybrid multilayer composite membranes exhibited an enhanced CO2 selectiv4 ity by a factor of two relative to the pure Pebax®. In these hybrid systems, the CO2 separation was presumably enhanced by the high ether oxides content from PEG POSS® that has high affinities for CO2. For particular composition of Pebax® and PEG POSS® concentrations, the PTMSP gutter layer harnessed the CO2 selectivity without losing the CO2 permeation rate. At the same time, these membrane, however, suffered severe adhesion between the gutter layer

  14. Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement

    Directory of Open Access Journals (Sweden)

    Mehran Tehrani

    2014-05-01

    Full Text Available Carbon nanofilament and nanotubes (CNTs have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD, in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures—from ethylene mixtures at 550 °C—on commercial polyacrylonitrile (PAN-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD technique was also utilized to grow multiwall CNTs (MWCNTs on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique.

  15. Electrical conductivity of short carbon fibers and carbon black-reinforced chloroprene rubber

    International Nuclear Information System (INIS)

    Khoshniat, A. R.; MirAli, M.; Hemmati, M.; Afshar Taromi, F.; Katbab, A.

    2002-01-01

    Elastomers and plastics are intrinsically insulating materials, but by addition of some conductive particles such as conductive carbon black, carbon fibers and metals, they can change to conductive form. Conductivity of these composites are due to formation of the lattices of conductive filler particles in polymer chains. In this report, conductivity of chloroprene rubber filled with carbon black and carbon fibers as a function of temperature and pressure are studied. Electrical conductivity of chloroprene in a function of temperature and pressure are studied. Electrical conductivity of chloroprene in the presence of carbon black with proper mixing conditions increases to the conductivity level of semiconductors and even in the presence of carbon fibers it increases to the level of a conductor material. Meanwhile, the sensitivity of this compound to heat and pressure rises. Thus these composites have found various applications in the manufacture of heat and pressure sensitive sensors

  16. Crystallization characteristics of ammonium uranyl carbonate (AUC) in ammonium carbonate solutions

    International Nuclear Information System (INIS)

    Kim, T.J.; Jeong, K.C.; Park, J.H.; Chang, I.S.; Choi, C.S.

    1994-01-01

    Ammonium carbonate solutions with an excessive amount of NH 3 were produced in a commercial AUC (ammonium uranyl carbonate) conversion plant. In this study the AUC crystals, precipitated with uranyl nitrate and ammonium carbonate solutions prepared in the laboratory, were characterized to determine the feasibility of recycling ammonium carbonate solution. The AUC crystals were easily agglomerated with the increasing concentration of CO 3 2- and mole ratio of NH 4 + /CO 3 2- in ammonium carbonate solution. Effects of a mixing system for the solution in the AUC crystallizer and the feed location of the solution onthe agglomeration of AUC crystals were also studied along with the effects of agglomerated AUC powders on UO 2 powders. Finally, the feasibility of manufacturing UO 2 fuel with a sintered pellet density of 10.52 g/cm 3 , using the AUC powders generated in this experiment, was demonstrated. (orig.)

  17. Carbon substituting for oxygen in silicates: A novel mechanism for carbon incorporation in the deep Earth

    Science.gov (United States)

    Armentrout, M. M.; Tavakoli, A.; Ionescu, E.; Mera, G.; Riedel, R.; Navrotsky, A.

    2013-12-01

    Traditionally, carbon in the deep Earth has been thought of in terms of either carbonate at high oxygen fugacities or graphite or diamond under more reducing conditions. However, material science studies of amorphous Si-O-C polymer derived ceramics have demonstrated that carbon can be accommodated as an anion substituting for oxygen in mixed silica tetrahedra. Furthermore these structures are energetically favorable relative to a mixture of crystalline silica, silicon carbide, and graphite by ten or more kJ/g.atom. Thermodynamic stability suggests that these nano-structured composites are a potentially important storage mechanism for carbon under moderately reducing conditions. Here we expand the scope of the previous work by examining the compositional effect of geologically relevant cations (calcium and magnesium) on the thermodynamic stability, nanostructure, and ability to accommodate carbon of these composites. Silicon oxy-carbides doped with magnesium, magnesium and calcium or undoped resisted crystallization at 1100 C under inert atmosphere. 29Si NMR of the samples shows a similar distribution of silicon between end-member and mixed sites (Table 1). Results are presented from studies utilizing NMR, high temperature solution calorimetry, and microprobe. Table 1. Percentages of Si species in each material as determined by 29Si NMR.

  18. Scenarios for low carbon and low water electric power plant ...

    Science.gov (United States)

    In the water-energy nexus, water use for the electric power sector is critical. Currently, the operational phase of electric power production dominates the electric sector's life cycle withdrawal and consumption of fresh water resources. Water use associated with the fuel cycle and power plant equipment manufacturing phase is substantially lower on a life cycle basis. An outstanding question is: how do regional shifts to lower carbon electric power mixes affect the relative contribution of the upstream life cycle water use? To test this, we examine a range of scenarios comparing a baseline with scenarios of carbon reduction and water use constraints using the MARKet ALlocation (MARKAL) energy systems model with ORD's 2014 U.S. 9-region database (EPAUS9r). The results suggest that moving toward a low carbon and low water electric power mix may increase the non-operational water use. In particular, power plant manufacturing water use for concentrating solar power, and fuel cycle water use for biomass feedstock, could see sharp increases under scenarios of high deployment of these low carbon options. Our analysis addresses the following questions. First, how does moving to a lower carbon electricity generation mix affect the overall regional electric power water use from a life cycle perspective? Second, how does constraining the operational water use for power plants affect the mix, if at all? Third, how does the life cycle water use differ among regions under

  19. Performance of diesel engine using diesel B3 mixed with crude palm oil.

    Science.gov (United States)

    Namliwan, Nattapong; Wongwuttanasatian, Tanakorn

    2014-01-01

    The objective of this study was to test the performance of diesel engine using diesel B3 mixed with crude palm oil in ratios of 95 : 5, 90 : 10, and 85 : 15, respectively, and to compare the results with diesel B3. According to the tests, they showed that the physical properties of the mixed fuel in the ratio of 95 : 5 were closest to those of diesel B3. The performance of the diesel engine that used mixed fuels had 5-17% lower torque and power than that of diesel B3. The specific fuel consumption of mixed fuels was 7-33% higher than using diesel B3. The components of gas emissions by using mixed fuel had 1.6-52% fewer amount of carbon monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2), and oxygen (O2) than those of diesel B3. On the other hand, nitric oxide (NO) and nitrogen oxides (NO X ) emissions when using mixed fuels were 10-39% higher than diesel B3. By comparing the physical properties, the performance of the engine, and the amount of gas emissions of mixed fuel, we found out that the 95 : 5 ratio by volume was a suitable ratio for agricultural diesel engine (low-speed diesel engine).

  20. Carbon isotope ratios in field Population II giant stars

    International Nuclear Information System (INIS)

    Sneden, C.; Pilachowski, C.A.; Vandenberg, D.A.; Kitt Peak National Observatory, Tucson, AZ; Victoria Univ., Canada)

    1986-01-01

    Carbon isotope ratios have been derived from high-resolution spectra of the CH G-band in 15 very metal-poor Population II giant stars and two similar dwarf stars. Many of the giants possess very low C-12/C-13 ratios, some approaching the CN cycle equilibrium value. The metal-poor dwarfs do not have detectable CH-13 features; thus the low carbon isotope ratios in the giants probably are due to their internal evolutions. These results strongly support the idea that at least part of the anomalously low C/N values in Population II giants arises from very efficient mixing of their envelopes into the CN cycle burning layers. Detailed calculations of the expected CNO surface abundances in Population II giants in different evolutionary states have been performed. These computations demonstrate that the observed carbon isotope ratios cannot be produced during the first dredge-up mixing phases in low-mass, low metal abundance stars. Numerical experiments show that theoretical and observational results can be brought into agreement with artificially induced extra mixing. An agent to provoke this additional mixing has not been identified with certainty yet, although internal stellar rotation is a promising candidate. 63 references

  1. Soil respiration response to prescribed burning and thinning in mixed-conifer and hardwood forests

    Science.gov (United States)

    Amy Concilio; Siyan Ma; Qinglin Li; James LeMoine; Jiquan Chen; Malcolm North; Daryl Moorhead; Randy Jensen

    2005-01-01

    The effects of management on soil carbon efflux in different ecosystems are still largely unknown yet crucial to both our understanding and management of global carbon flux. To compare the effects of common forest management practices on soil carbon cycling, we measured soil respiration rate (SRR) in a mixed-conifer and hardwood forest that had undergone various...

  2. Oil mixing behavior after an oil spill: identification conflicts of different fingerprints.

    Science.gov (United States)

    He, Shijie; Yu, Hongjun; Luo, Yongming; Wang, Chuanyuan; Li, Xueshuang; Li, Zhongping

    2018-04-01

    Clearing up whether spilled oil is mixed or not can strengthen the accuracy of oil spill identification. In the present study, the biomarkers in spilled oil samples were detected. The weathering modes of different types of diagnostic ratio and carbon isotope values of individual n-alkanes were also analyzed. The results showed that the diagnostic ratios of steroids, terpenes and aromatics, and weathering characteristics of carbon isotope composition (δ 13 C) of individual n-alkanes supported the idea that Dalian oil spill emerged from a single oil source. Furthermore, commonly used diagnostic ratios of n-alkanes indicated that the Dalian oil spill had undergone the oil mixing process. The different identifying outcomes indicate that some kinds of n-alkane-rich substance (such as oil dispersants) were mixed in the Dalian spilled oil and interfered with the routine diagnosis ratios of n-alkanes.

  3. The single-particle mixing state and cloud scavenging of black carbon: a case study at a high-altitude mountain site in southern China

    Science.gov (United States)

    Zhang, Guohua; Lin, Qinhao; Peng, Long; Bi, Xinhui; Chen, Duohong; Li, Mei; Li, Lei; Brechtel, Fred J.; Chen, Jianxin; Yan, Weijun; Wang, Xinming; Peng, Ping'an; Sheng, Guoying; Zhou, Zhen

    2017-12-01

    In the present study, a ground-based counterflow virtual impactor (GCVI) was used to sample cloud droplet residual (cloud RES) particles, while a parallel PM2.5 inlet was used to sample cloud-free or cloud interstitial (cloud INT) particles. The mixing state of black carbon (BC)-containing particles and the mass concentrations of BC in the cloud-free, RES and INT particles were investigated using a single-particle aerosol mass spectrometer (SPAMS) and two aethalometers, respectively, at a mountain site (1690 m a. s. l. ) in southern China. The measured BC-containing particles were extensively internally mixed with sulfate and were scavenged into cloud droplets (with number fractions of 0.05-0.45) to a similar (or slightly lower) extent as all the measured particles (0.07-0.6) over the measured size range of 0.1-1.6 µm. The results indicate the preferential activation of larger particles and/or that the production of secondary compositions shifts the BC-containing particles towards larger sizes. BC-containing particles with an abundance of both sulfate and organics were scavenged less than those with sulfate but limited organics, implying the importance of the mixing state on the incorporation of BC-containing particles into cloud droplets. The mass scavenging efficiency of BC with an average of 33 % was similar for different cloud events independent of the air mass. This is the first time that both the mixing state and cloud scavenging of BC in China have been reported. Our results would improve the knowledge on the concentration, mixing state, and cloud scavenging of BC in the free troposphere.

  4. Revised (Mixed-Effects) Estimation for Forest Burning Emissions of Gases and Smoke, Fire/Emission Factor Typology, and Potential Remote Sensing Classification of Types for Ozone and Black-Carbon Simulation

    Science.gov (United States)

    Chatfield, Robert B.; Segal Rozenhaimer, M.

    2014-01-01

    We summarize recent progress (a) in correcting biomass burning emissions factors deduced from airborne sampling of forest fire plumes, (b) in understanding the variability in reactivity of the fresh plumes sampled in ARCTAS (2008), DC3 (2012), and SEAC4RS (2013) airborne missions, and (c) in a consequent search for remotely sensed quantities that help classify forest-fire plumes. Particle properties, chemical speciation, and smoke radiative properties are related and mutually informative, as pictures below suggest (slopes of lines of same color are similar). (a) Mixed-effects (random-effects) statistical modeling provides estimates of both emission factors and a reasonable description of carbon-burned simultaneously. Different fire plumes will have very different contributions to volatile organic carbon reactivity; this may help explain differences of free NOx(both gas- and particle-phase), and also of ozone production, that have been noted for forest-fire plumes in California. Our evaluations check or correct emission factors based on sequential measurements (e.g., the Normalized Ratio Enhancement and similar methods). We stress the dangers of methods relying on emission-ratios to CO. (b) This work confirms and extends many reports of great situational variability in emissions factors. VOCs vary in OH reactivity and NOx-binding. Reasons for variability are not only fuel composition, fuel condition, etc., but are confused somewhat by rapid transformation and mixing of emissions. We use "unmixing" (distinct from mixed-effects) statistics and compare briefly to approaches like neural nets. We focus on one particularly intense fire the notorious Yosemite Rim Fire of 2013. In some samples, NOx activity was not so suppressed by binding into nitrates as in other fires. While our fire-typing is evolving and subject to debate, the carbon-burned delta(CO2+CO) estimates that arise from mixed effects models, free of confusion by background-CO2 variation, should provide a

  5. Enhanced solubilization of curcumin in mixed surfactant vesicles.

    Science.gov (United States)

    Kumar, Arun; Kaur, Gurpreet; Kansal, S K; Chaudhary, Ganga Ram; Mehta, S K

    2016-05-15

    Self-assemblies of equimolar double and single chain mixed ionic surfactants, with increasing numbers of carbon atoms of double chain surfactant, were analyzed on the basis of fluorescence and conductivity results. Attempts were also made to enhance the solubilization of curcumin in aqueous equimolar mixed surfactant systems. Mixed surfactant assembly was successful in retarding the degradation of curcumin in alkaline media (only 25-28 40% degraded in 10h at pH 13). Fluorescence spectroscopy and fluorescence quenching methods were employed to predict the binding position and mechanism of curcumin with self-assemblies. Results indicate that the interactions take place according to both dynamic and static quenching mechanisms and curcumin was distributed in a palisade layer of mixed aggregates. Antioxidant activity (using DPPH radical) and biocompatibility (using calf-thymus DNA) of curcumin-loaded mixed surfactant formulations were also evaluated. The prepared systems improved the stability, solubility and antioxidant activity of curcumin and additionally are biocompatible. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Application of laser-induced breakdown spectroscopy in carbon ...

    Indian Academy of Sciences (India)

    in carbon sequestration research and development ... design and use of fibre optics make it a suitable technique for real-time ... The currently available methods typically ... Subsequent analysis of the radiation gives qualitative and quantitative ... The soil samples were finely ground, filtered, mixed with carbon powder in.

  7. Using Flow Electrodes in Multiple Reactors in Series for Continuous Energy Generation from Capacitive Mixing

    KAUST Repository

    Hatzell, Marta C.

    2014-12-09

    Efficient conversion of “mixing energy” to electricity through capacitive mixing (CapMix) has been limited by low energy recoveries, low power densities, and noncontinuous energy production resulting from intermittent charging and discharging cycles. We show here that a CapMix system based on a four-reactor process with flow electrodes can generate constant and continuous energy, providing a more flexible platform for harvesting mixing energy. The power densities were dependent on the flow-electrode carbon loading, with 5.8 ± 0.2 mW m–2 continuously produced in the charging reactor and 3.3 ± 0.4 mW m–2 produced in the discharging reactor (9.2 ± 0.6 mW m–2 for the whole system) when the flow-electrode carbon loading was 15%. Additionally, when the flow-electrode electrolyte ion concentration increased from 10 to 20 g L–1, the total power density of the whole system (charging and discharging) increased to 50.9 ± 2.5 mW m–2.

  8. Mixing-Structure Relationship in Jet-Stirred Reactors

    KAUST Repository

    Ayass, Wassim W.

    2016-05-26

    In this study, measurements were performed to assess the overall mixing in jet-stirred reactors (JSRs) passively agitated by feed nozzles. The reactor diameter, nozzle shape, and nozzle diameter were varied to determine the effects of these geometrical parameters on mixing. The mixing was studied at ambient conditions using laser absorption spectroscopy to follow the exit concentration of a tracer gas, carbon dioxide, after a step change in its input flow. The results indicate that the use of a JSR of diameter D = 40 mm, having inclined or crossed nozzles of diameter d = 1 mm is recommended for low residence times up to 0.4 sec, while at moderate/high residence times 0.5-5 sec the use of a JSR of D = 56 mm and d = 0.3 mm having crossed nozzles is suggested.

  9. Surface and Adsorption Properties of Activated Carbon Fabric Prepared from Cellulosic Polymer: Mixed Activation Method

    Energy Technology Data Exchange (ETDEWEB)

    Bhati, Surendra; Mahur, J. S.; Choubey, O. N. [Barkatullah Univ., Bhopal (India); Dixit, Mahur Savita [Maulana Azad National Institute of Technology, Bhopla (India)

    2013-02-15

    In this study, activated carbon fabric was prepared from a cellulose-based polymer (viscose rayon) via a combination of physical and chemical activation (mixed activation) processes by means of CO{sub 2} as a gasifying agent and surface and adsorption properties were evaluated. Experiments were performed to investigate the consequence of activation temperature (750, 800, 850 and 925 .deg. C), activation time (15, 30, 45 and 60 minutes) and CO{sub 2} flow rate (100, 200, 300 and 400 mL/min) on the surface and adsorption properties of ACF. The nitrogen adsorption isotherm at 77 K was measured and used for the determination of surface area, total pore volume, micropore volume, mesopore volume and pore size distribution using BET, t-plot, DR, BJH and DFT methods, respectively. It was observed that BET surface area and TPV increase with rising activation temperature and time due to the formation of new pores and the alteration of micropores into mesopores. It was also found that activation temperature dominantly affects the surface properties of ACF. The adsorption of iodine and CCl{sub 4} onto ACF was investigated and both were found to correlate with surface area.

  10. Surface and Adsorption Properties of Activated Carbon Fabric Prepared from Cellulosic Polymer: Mixed Activation Method

    International Nuclear Information System (INIS)

    Bhati, Surendra; Mahur, J. S.; Choubey, O. N.; Dixit, Mahur Savita

    2013-01-01

    In this study, activated carbon fabric was prepared from a cellulose-based polymer (viscose rayon) via a combination of physical and chemical activation (mixed activation) processes by means of CO 2 as a gasifying agent and surface and adsorption properties were evaluated. Experiments were performed to investigate the consequence of activation temperature (750, 800, 850 and 925 .deg. C), activation time (15, 30, 45 and 60 minutes) and CO 2 flow rate (100, 200, 300 and 400 mL/min) on the surface and adsorption properties of ACF. The nitrogen adsorption isotherm at 77 K was measured and used for the determination of surface area, total pore volume, micropore volume, mesopore volume and pore size distribution using BET, t-plot, DR, BJH and DFT methods, respectively. It was observed that BET surface area and TPV increase with rising activation temperature and time due to the formation of new pores and the alteration of micropores into mesopores. It was also found that activation temperature dominantly affects the surface properties of ACF. The adsorption of iodine and CCl 4 onto ACF was investigated and both were found to correlate with surface area

  11. Pliocene-Lower Pleistocene shallow-water mixed siliciclastics and carbonates (Yanigua and Los Haitises formations) in eastern Hispaniola (Dominican Republic)

    Science.gov (United States)

    Braga, Juan C.; Díaz de Neira, Alberto; Lasseur, Eric; Mediato, José; Aguirre, Julio; Abad, Manuel; Hernaiz-Huerta, Pedro P.; Monthel, Jacques; Pérez-Valera, Fernando; Lopera, Eusebio

    2012-07-01

    The virtually unfolded sedimentary cover of the Cordilleras Central and Oriental in the eastern Dominican Republic (eastern Hispaniola, tropical North Atlantic) largely consists of Pliocene to Early Pleistocene mixed siliciclastics and carbonates. These deposits have been grouped into two laterally interfingering mapping units, the Yanigua and Los Haitises formations. The former (mainly siliciclastics) comprises marl, marly limestone, and minor conglomerate, sandstone, lignite, and carbonaceous clay and crops out closest to the basement. The Los Haitises Formation mainly consists of limestone and intercalating beds of marly limestone and marl. Lithological mapping at the 1:50,000 scale and facies analysis of twelve measured sections and of additional fourteen outcrops suggest that these deposits mainly formed on a shallow-water marine platform fringing the precursor reliefs of the Cordillera Oriental and the southeastern end of the Cordillera Central. Only a limited proportion of sediment formed in floodplains and marshes. Marl and marly limestone dominated the inner platform sediments. Terrigenous mud decreased away from the emergent basement and carbonate sedimentation dominated the more external platform. Corals, molluscs, echinoids, foraminifers, bryozoans, coralline algae, and Halimeda are the main components with varying amounts of carbonate mud. The platform was generally a low-energy environment with seagrass patches. In the inner platform, corals grew as isolated colonies or as small patch reefs dominated by Porites in marly and bioclastic substrates. Branching corals (Stylophora and Acropora) grew in extensive carpets in more distal areas. At least in the last stage of its development (Early Pleistocene), the platform was rimmed by a reef barrier similar to the Holocene Caribbean barrier reefs, with Acropora gr. palmata, A. cervicornis, Porites, Montastrea, Siderastrea, and Diploria as the main reef builders.

  12. Crosslinkable mixed matrix membranes with surface modified molecular sieves for natural gas purification: II. Performance characterization under contaminated feed conditions

    KAUST Repository

    Ward, Jason K.

    2011-07-01

    Mixed matrix membranes (MMMs) composed of the crosslinkable polyimide PDMC and surface modified (SM) SSZ-13 have recently been shown to enhance carbon dioxide permeability and carbon dioxide/methane selectivity versus neat PDMC films by as much as 47% and 13%, respectively (Part I). The previous film characterization, however, was performed using ideal, clean mixed gas feeds. In this paper, PDMC/SSZ-13 MMMs are further characterized using more realistic mixed gases containing low concentrations (500 or 1000. ppm) of toluene as a model contaminant. Mixed matrix membranes are shown to outperform pure PDMC films in the presence of toluene with 43% greater carbon dioxide permeability and 12% greater carbon dioxide/selectivity at 35 °C and 700 psia feed pressure. These results suggest that MMMs-in addition to exhibiting enhanced transport properties-may mitigate performance degradation due to antiplasticization effects. Moreover, the analyses presented here show that the reduction in separation performance by trace contaminant-accelerated physical aging can be suppressed greatly with MMMs. © 2011 Elsevier B.V.

  13. Fire suppression and fuels treatment effects on mixed-conifer carbon stocks and emissions

    Science.gov (United States)

    M. North; M Hurteau; J Innes

    2009-01-01

    Depending on management, forests can be an important sink or source of carbon that if released as CO2 could contribute to global warming. Many forests in the western United States are being treated to reduce fuels, yet the effects of these treatments on forest carbon are not well understood. We compared the immediate effects of fuels treatments on carbon stocks and...

  14. Mixed waste treatment using the ChemChar thermolytic detoxification technique

    Energy Technology Data Exchange (ETDEWEB)

    Kuchynka, D.

    1995-12-31

    The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. Versatility of the treatment technology, volume reduction and containment of the radioactive component of the mixed waste streams are three criteria to be considered when evaluating potential treatment technologies. The ChemChar thermolytic detoxification process being developed under this R and D contract is a thermal, chemically reductive technology that converts the organic portion of a mixed waste stream to an energy-rich synthesis gas while simultaneously absorbing volatile inorganic species (metals and acid gases) on a macroporous, carbon-based char. The latter is mixed with the waste stream prior to entering the reactor. Substoichiometric amounts of oxidant are fed into the top portion of the cylindrical reactor generating a thin, radial thermochemical reaction zone. This zone generates all the necessary heat to promote the highly endothermic reduction of the organic components in the waste in the lower portion of the reactor, producing, principally, hydrogen and carbon monoxide. The solid by-product is a regenerated carbon char that, depending on the inorganic loading, is capable for reuse. The in situ scrubbing of contaminants by the char within the reactor coupled with a char filter for final polishing produce an exceptionally clean synthesis gas effluent suitable for on-site generation of heat, steam or electricity. Despite the elevated temperatures in the thermochemical reaction zone, the reductive nature of the process precludes formation of nitrogen oxides and halogenated organic compound by-products.

  15. Mixed waste treatment using the ChemChar thermolytic detoxification technique

    International Nuclear Information System (INIS)

    Kuchynka, D.

    1995-01-01

    The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. Versatility of the treatment technology, volume reduction and containment of the radioactive component of the mixed waste streams are three criteria to be considered when evaluating potential treatment technologies. The ChemChar thermolytic detoxification process being developed under this R and D contract is a thermal, chemically reductive technology that converts the organic portion of a mixed waste stream to an energy-rich synthesis gas while simultaneously absorbing volatile inorganic species (metals and acid gases) on a macroporous, carbon-based char. The latter is mixed with the waste stream prior to entering the reactor. Substoichiometric amounts of oxidant are fed into the top portion of the cylindrical reactor generating a thin, radial thermochemical reaction zone. This zone generates all the necessary heat to promote the highly endothermic reduction of the organic components in the waste in the lower portion of the reactor, producing, principally, hydrogen and carbon monoxide. The solid by-product is a regenerated carbon char that, depending on the inorganic loading, is capable for reuse. The in situ scrubbing of contaminants by the char within the reactor coupled with a char filter for final polishing produce an exceptionally clean synthesis gas effluent suitable for on-site generation of heat, steam or electricity. Despite the elevated temperatures in the thermochemical reaction zone, the reductive nature of the process precludes formation of nitrogen oxides and halogenated organic compound by-products

  16. Performance of Diesel Engine Using Diesel B3 Mixed with Crude Palm Oil

    Science.gov (United States)

    Namliwan, Nattapong; Wongwuttanasatian, Tanakorn

    2014-01-01

    The objective of this study was to test the performance of diesel engine using diesel B3 mixed with crude palm oil in ratios of 95 : 5, 90 : 10, and 85 : 15, respectively, and to compare the results with diesel B3. According to the tests, they showed that the physical properties of the mixed fuel in the ratio of 95 : 5 were closest to those of diesel B3. The performance of the diesel engine that used mixed fuels had 5–17% lower torque and power than that of diesel B3. The specific fuel consumption of mixed fuels was 7–33% higher than using diesel B3. The components of gas emissions by using mixed fuel had 1.6–52% fewer amount of carbon monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2), and oxygen (O2) than those of diesel B3. On the other hand, nitric oxide (NO) and nitrogen oxides (NOX) emissions when using mixed fuels were 10–39% higher than diesel B3. By comparing the physical properties, the performance of the engine, and the amount of gas emissions of mixed fuel, we found out that the 95 : 5 ratio by volume was a suitable ratio for agricultural diesel engine (low-speed diesel engine). PMID:24688402

  17. Hybrid membrane using polyethersulfone-modification of multiwalled carbon nanotubes with silane agent to enhance high performance oxygen separation

    Directory of Open Access Journals (Sweden)

    Tutuk Djoko Kusworo

    2014-04-01

    Full Text Available Mixed matrix membrane comprising carbon nanotubes embedded in polymer matrix have become one of the emerging technologies. This study was investigated in order to study the effect of silane agent modification towards carbon nanotubes (CNT surface at different concentration on oxygen enrichment performances of asymmetric mixed matrix membrane. The modified carbon nanotubes were prepared by treating the carbon nanotubes with chemical modification using Dynasylan Ameo (DA silane agent to allow PES chains to be grafted on carbon nanotubes surface. The results from the FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Sieve-in-a-cage’ morphology observed shows the poor adhesion between polymer and unmodified CNT. The gas separation performance of the asymmetric flat sheet mixed matrix membranes with modified CNT were relatively higher compared to the unmodified CNT. Hence, coated hollow fiber mixed matrix membrane with chemical modification on CNT surface using (3-aminopropyl-triethoxy methyl silane agent can potentially enhance the gas separation performance of O2 and N2.

  18. Preparation of carbon nanotubes/epoxy resin composites by using hollow glass beads as the carrier

    International Nuclear Information System (INIS)

    Wu, X.F.; Zhao, Y.K.; Zhang, D.; Chen, T.B.; Ma, L.Y.

    2012-01-01

    Hollow glass beads had been utilized as the carrier to assist dispersion of carbon nanotubes in epoxy resin. Hollow glass beads were firstly aminated with gamma-aminopropyl-triethoxysilane, sencondly reacted with carboxyl-functionalized carbon nanotubes via an amidation reaction and susequently mixed with epoxy resin and hardener. The experimental results showed that carbon nanotubes could be loaded on the surfaces of hollow glass beads and approximately a monolayer of carbon nanotubes was formed when the weight ratio of hollow glass beads to carbon nanotubes was 100:5. Moreover, the dispersity of carbon nanotubes in the matrix was improved as compared to the control samples prepared by using a conventional mixing method. (author)

  19. Changes in ocean circulation and carbon storage are decoupled from air-sea CO2 fluxes

    Science.gov (United States)

    Marinov, I.; Gnanadesikan, A.

    2011-02-01

    The spatial distribution of the air-sea flux of carbon dioxide is a poor indicator of the underlying ocean circulation and of ocean carbon storage. The weak dependence on circulation arises because mixing-driven changes in solubility-driven and biologically-driven air-sea fluxes largely cancel out. This cancellation occurs because mixing driven increases in the poleward residual mean circulation result in more transport of both remineralized nutrients and heat from low to high latitudes. By contrast, increasing vertical mixing decreases the storage associated with both the biological and solubility pumps, as it decreases remineralized carbon storage in the deep ocean and warms the ocean as a whole.

  20. Changes in ocean circulation and carbon storage are decoupled from air-sea CO2 fluxes

    Directory of Open Access Journals (Sweden)

    A. Gnanadesikan

    2011-02-01

    Full Text Available The spatial distribution of the air-sea flux of carbon dioxide is a poor indicator of the underlying ocean circulation and of ocean carbon storage. The weak dependence on circulation arises because mixing-driven changes in solubility-driven and biologically-driven air-sea fluxes largely cancel out. This cancellation occurs because mixing driven increases in the poleward residual mean circulation result in more transport of both remineralized nutrients and heat from low to high latitudes. By contrast, increasing vertical mixing decreases the storage associated with both the biological and solubility pumps, as it decreases remineralized carbon storage in the deep ocean and warms the ocean as a whole.

  1. Mixed waste treatment using the ChemChar thermolytic detoxification technique

    Energy Technology Data Exchange (ETDEWEB)

    Kuchynka, D. [Mirage Systems, Sunnyvale, CA (United States)

    1995-10-01

    The diversity of mixed waste matrices contained at Department of Energy sites that require treatment preclude a single, universal treatment technology capable of handling sludges, solids, heterogeneous debris, aqueous and organic liquids and soils. This report describes the ChemChar thermolytic detoxification process. The process is a thermal, chemically reductive technology that converts the organic portion of mixed wastes to a synthesis gas, while simultaneously absorbing volatile inorganics on a carbon-based char.

  2. High pressure pure- and mixed-gas separation of CO2/CH4 by thermally-rearranged and carbon molecular sieve membranes derived from a polyimide of intrinsic microporosity

    KAUST Repository

    Swaidan, Raja

    2013-11-01

    Natural gas sweetening, one of the most promising venues for the growth of the membrane gas separation industry, is dominated by polymeric materials with relatively low permeabilities and moderate selectivities. One strategy towards improving the gas transport properties of a polymer is enhancement of microporosity either by design of polymers of intrinsic microporosity (PIMs) or by thermal treatment of polymeric precursors. For the first time, the mixed-gas CO2/CH4 transport properties are investigated for a complete series of thermally-rearranged (TR) (440°C) and carbon molecular sieve (CMS) membranes (600, 630 and 800°C) derived from a polyimide of intrinsic microporosity (PIM-6FDA-OH). The pressure dependence of permeability and selectivity is reported up to 30bar for 1:1, CO2:CH4 mixed-gas feeds at 35°C. The TR membrane exhibited ~15% higher CO2/CH4 selectivity relative to pure-gas feeds due to reductions in mixed-gas CH4 permeability reaching 27% at 30bar. This is attributed to increased hindrance of CH4 transport by co-permeation of CO2. Interestingly, unusual increases in mixed-gas CH4 permeabilities relative to pure-gas values were observed for the CMS membranes, resulting in up to 50% losses in mixed-gas selectivity over the applied pressure range. © 2013 Elsevier B.V.

  3. Transesterification of Jatropha oil with dimethyl carbonate to produce fatty acid methyl ester over reusable Ca–La–Al mixed-oxide catalyst

    International Nuclear Information System (INIS)

    Syamsuddin, Y.; Murat, M.N.; Hameed, B.H.

    2015-01-01

    Highlights: • Transesterification of Jatropha oil over CaO-based catalyst. • Physicochemical properties of the synthesized catalyst. • Best reaction condition for FAME synthesis. • The catalyst showed high activity and stability for transesterification with Jatropha oil. - Abstract: Jatropha oil (JO) was transesterified with dimethyl carbonate (DMC) to produce fatty acid methyl ester (FAME) over synthesized Ca–La–Al mixed-oxide catalyst. The influence of different parameters on transesterification of Jatropha oil was investigated in a batch reactor. These parameters included reaction temperature (110–160 °C), reaction time (30–240 min), DMC-to-oil molar ratio (4:1–18:1) and catalyst loading amount (1–10 wt.%, based on the oil weight). The mixed-oxide catalyst with a molar ratio of 6:2:1 (Ca–La–Al) showed high catalytic activity for FAME synthesis. More than 90% of FAME was obtained under the following reaction conditions: 150 °C, reaction temperature; 180 min, reaction time; 15:1, DMC-to-oil molar ratio; and 7 wt.% amount of catalyst loading. The catalyst also exhibited high stability and could be reused for up to five cycles with less than 5% yield reduction per cycle.

  4. Controlling the set of carbon-fiber embedded cement with electric current

    Science.gov (United States)

    Mattus, Alfred J.

    2004-06-15

    A method for promoting cement or concrete set on demand for concrete that has been chemically retarded by adding carbon fiber to the concrete, which enables it to become electrically conductive, sodium tartrate retardant, and copper sulfate which forms a copper tartrate complex in alkaline concrete mixes. Using electricity, the concrete mix anodically converts the retarding tartrate to an insoluble polyester polymer. The carbon fibers act as a continuous anode surface with a counter electrode wire embedded in the mix. Upon energizing, the retarding effect of tartrate is defeated by formation of the polyester polymer through condensation esterification thereby allowing the normal set to proceed unimpeded.

  5. Measurement of carbon activity of sodium using nickel tabs and the Harwell Carbon Meter - Preliminary experience

    International Nuclear Information System (INIS)

    Blundell, A.; Thorley, A.W.

    1980-01-01

    Carbon can have an important effect on the mechanical properties of certain constructional materials likely to be used in the LMFBRs. Transfer of carbon will occur between the metal and the sodium at any particular location to bring the chemical potential of carbon in both components to the sam: value. Thus, in a mixed system containing austenitic stainless steel and unstabilized ferritic steel, carbon could be transferred by the sodium from the high carbon activity ferritic to the lower activity austenitic steel. Loss of carbon from the unstabilized ferritic steel leads to a weaker, more ductile material, while carburization of the stainless steel could lead to its embrittlement. Similarly carbon entering the coolant in the form of oil from leaking mechanical pumps could have similar effects on the mechanical property of stainless steels. In the light of these possibilities it is essential to measure the carbon activity of the sodium so that its effect on materials properties can be predicted

  6. Measurement of carbon activity of sodium using nickel tabs and the Harwell Carbon Meter - Preliminary experience

    Energy Technology Data Exchange (ETDEWEB)

    Blundell, A; Thorley, A W [UKAEA, Risley, Warrington, Cheshire (United Kingdom)

    1980-05-01

    Carbon can have an important effect on the mechanical properties of certain constructional materials likely to be used in the LMFBRs. Transfer of carbon will occur between the metal and the sodium at any particular location to bring the chemical potential of carbon in both components to the sam: value. Thus, in a mixed system containing austenitic stainless steel and unstabilized ferritic steel, carbon could be transferred by the sodium from the high carbon activity ferritic to the lower activity austenitic steel. Loss of carbon from the unstabilized ferritic steel leads to a weaker, more ductile material, while carburization of the stainless steel could lead to its embrittlement. Similarly carbon entering the coolant in the form of oil from leaking mechanical pumps could have similar effects on the mechanical property of stainless steels. In the light of these possibilities it is essential to measure the carbon activity of the sodium so that its effect on materials properties can be predicted.

  7. Mixing state of ambient aerosols during different fog-haze pollution episodes in the Yangtze River Delta, China

    Science.gov (United States)

    Hu, Rui; Wang, Honglei; Yin, Yan; Chen, Kui; Zhu, Bin; Zhang, Zefeng; Kang, Hui; Shen, Lijuan

    2018-04-01

    The mixing state of aerosol particles were investigated using a single particle aerosol mass spectrometer (SPAMS) during a regional fog-haze episode in the Yangtze River Delta (YRD) on 16-28 Dec., 2015. The aerosols were analyzed and clustered into 12 classes: aged elemental carbon (Aged-EC), internally mixed organics and elemental carbon (ECOC), organic carbon (OC), Biomass, Amine, Ammonium, Na-K, V-rich, Pb-rich, Cu-rich, Fe-rich and Dust. Results showed that particles in short-term rainfalls mixed with more nitrate and oxidized organics, while they mixed with more ammonium and sulfate in long-term rainfall. Due to anthropogenic activities, stronger winds and solar radiation, the particle counts increased and the size ranges of particles broadened in haze. Carbonaceous particles and Na-K mixed with enhanced secondary species during haze, and obviously were more acidic, especially for the ones with a size range of 0.6-1.2 μm. For local and long-range transported pollution, OC had distinct size distributions while the changes of ECOC were uniform. The secondary formation of ECOC contributed significantly in local pollution and affected much smaller particles (as small as 0.5 μm) in long-range transported pollution. And long-range transported pollution was more helpful for the growth of OC. Particles mixed with more chloride and nitrate/sulfate in local/long-range transported pollution.

  8. Penelitian pengaruh campuran carbon black dan china clay terhadap sifat tegangan putus dan kekerasan karet vulkanisat

    Directory of Open Access Journals (Sweden)

    Supraptiningsih Supraptiningsih

    1999-07-01

    Full Text Available It has been done a research of the influence of mixed carbon black and hardness properties on the vulcanization of rubber. It has been made with additive of carbon black and china clay mixed, in total variation. The result is seen that total variation of carbon black and china clay not influence to tensile strength, but their interacton can do it. The hardness of vulcanization of rubber will be influence by total variation of carbon black china clay anad their interaction.

  9. Gas adsorption and gas mixture separations using mixed-ligand MOF material

    Science.gov (United States)

    Hupp, Joseph T [Northfield, IL; Mulfort, Karen L [Chicago, IL; Snurr, Randall Q [Evanston, IL; Bae, Youn-Sang [Evanston, IL

    2011-01-04

    A method of separating a mixture of carbon dioxiode and hydrocarbon gas using a mixed-ligand, metal-organic framework (MOF) material having metal ions coordinated to carboxylate ligands and pyridyl ligands.

  10. Acoustic Velocity Data for Clay Bearing Carbonate Rocks

    DEFF Research Database (Denmark)

    Lind, Ida; Shogenova, Alla

    1998-01-01

    Two sets of acoustic data on carbonates were combined to span the porosity interval from below 5% to more than 75%: dolomite and limestone of Paleozoic age from Estonia and mixed sediments from the Caribbean. The carbonate content of the samples ranges from less than 50% to 100%, and it was attem...

  11. Carbon-14 as an hydrology tool

    International Nuclear Information System (INIS)

    Garcia y G, E.; Albarran B, R.

    1977-01-01

    Carbon-14 and tritium results from the action of cosmic radiation and of nuclear tests also. In general carbon-14 resulting from nuclear arms tests is of no interest from the hydrological point-of view, as tritium is a more efficient marker of juvenile waters through having a much shorter disintegration period. Radioactive carbon oxidizes and forms carbon dioxide which mixes with atmospheric carbon dioxide and enters the global carbon cycle. Use of carbon-14 in the dating of subterranean waters is based on the fact that the carbon dioxide found in the soil zone is of biologic origin arising from the respiration and decomposition of plant roots. Therefore it contains carbon-14 taken from the atmosphere by the plants. This carbon dioxide of biogenic origin is dissolved in infiltrating water and is borne along towards the water bearing strata. Its carbon-14 content decrease through radioactive loss and the fractional remainder of the original contents indicates the time which has passed since it left the supply zone in the soil, that is, the time passed since it filtrated the water. (author)

  12. Less severe processing improves carbon nanotube photovoltaic performance

    Science.gov (United States)

    Shea, Matthew J.; Wang, Jialiang; Flach, Jessica T.; Zanni, Martin T.; Arnold, Michael S.

    2018-05-01

    Thin film semiconducting single walled carbon nanotube (s-SWCNT) photovoltaics suffer losses due to trapping and quenching of excitons by defects induced when dispersing s-SWCNTs into solution. We study these aspects by preparing photovoltaic devices from (6,5) carbon nanotubes isolated by different processes: extended ultrasonication, brief ultrasonication, and shear force mixing. Peak quantum efficiency increases from 28% to 38% to 49% as the processing harshness decreases and is attributed to both increasing s-SWCNT length and reducing sidewall defects. Fill-factor and open-circuit voltage also improve with shear force mixing, highlighting the importance of obtaining long, defect-free s-SWCNTs for efficient photoconversion devices.

  13. Carbon and nutrient mixed layer dynamics in the Norwegian Sea

    Directory of Open Access Journals (Sweden)

    H. S. Findlay

    2008-10-01

    Full Text Available A coupled carbon-ecosystem model is compared to recent data from Ocean Weather Station M (66° N, 02° E and used as a tool to investigate nutrient and carbon processes within the Norwegian Sea. Nitrate is consumed by phytoplankton in the surface layers over the summer; however the data show that silicate does not become rapidly limiting for diatoms, in contrast to the model prediction and in contrast to data from other temperate locations. The model estimates atmosphere-ocean CO2 flux to be 37 g C m−2 yr−1. The seasonal cycle of the carbonate system at OWS M resembles the cycles suggested by data from other high-latitude ocean locations. The seasonal cycles of calcite saturation state and [CO32-] are similar in the model and in data at OWS M: values range from ~3 and ~120 μmol kg−1 respectively in winter, to ~4 and ~170 μmol kg−1 respectively in summer. The model and data provide further evidence (supporting previous modelling work that the summer is a time of high saturation state within the annual cycle at high-latitude locations. This is also the time of year that coccolithophore blooms occur at high latitudes.

  14. Energetics of binary mixed culture of Pseudomonas aeruginosa and ...

    African Journals Online (AJOL)

    Bioenergetic analysis of the growth of the binary mixed culture (Pseudomonas aeruginosa and Pseudomonas fluorescence) on phenol chemostat culture was carried out. The data were checked for consistency using carbon and available electron balances. When more than the minimum number of variables are measured, ...

  15. Zonally asymmetric response of the Southern Ocean mixed-layer depth to the Southern Annular Mode

    Science.gov (United States)

    Sallée, J. B.; Speer, K. G.; Rintoul, S. R.

    2010-04-01

    Interactions between the atmosphere and ocean are mediated by the mixed layer at the ocean surface. The depth of this layer is determined by wind forcing and heating from the atmosphere. Variations in mixed-layer depth affect the rate of exchange between the atmosphere and deeper ocean, the capacity of the ocean to store heat and carbon and the availability of light and nutrients to support the growth of phytoplankton. However, the response of the Southern Ocean mixed layer to changes in the atmosphere is not well known. Here we analyse temperature and salinity data from Argo profiling floats to show that the Southern Annular Mode (SAM), the dominant mode of atmospheric variability in the Southern Hemisphere, leads to large-scale anomalies in mixed-layer depth that are zonally asymmetric. From a simple heat budget of the mixed layer we conclude that meridional winds associated with departures of the SAM from zonal symmetry cause anomalies in heat flux that can, in turn, explain the observed changes of mixed-layer depth and sea surface temperature. Our results suggest that changes in the SAM, including recent and projected trends attributed to human activity, drive variations in Southern Ocean mixed-layer depth, with consequences for air-sea exchange, ocean sequestration of heat and carbon, and biological productivity.

  16. Carbon dioxide selective mixed matrix composite membrane containing ZIF-7 nano-fillers

    KAUST Repository

    Li, Tao

    2013-01-01

    Mixed matrix materials made from selective inorganic fillers and polymers are very attractive for the manufacturing of gas separation membranes. But only few of these materials could be manufactured into high-performance asymmetric or composite membranes. We report here the first mixed matrix composite membrane made of commercially available poly (amide-b-ethylene oxide) (Pebax®1657, Arkema) mixed with the nano-sized zeolitic imidazole framework ZIF-7. This hybrid material has been successfully deposited as a thin layer (less than 1μm) on a porous polyacrylonitrile (PAN) support. An intermediate gutter layer of PTMSP was applied to serve as a flat and smooth surface for coating to avoid polymer penetration into the porous support. Key features of this work are the preparation and use of ultra-small ZIF-7 nano-particles (around 30-35nm) and the membrane processability of Pebax®1657. SEM pictures show that excellent adhesion and almost ideal morphology between the two phases has been obtained simply by mixing the as-synthesized ZIF-7 suspension into the Pebax®1657 dope, and no voids or clusters can be observed. The performance of the composite membrane is characterized by single gas permeation measurement of CO2, N2 and CH4. Both, permeability (PCO2 up to 145barrer) and gas selectivity (CO2/N2 up to 97 and CO2/CH4 up to 30) can be increased at low ZIF- loading. The CO2/CH4 selectivity can be further increased to 44 with the filler loading of 34wt%, but the permeability is reduced compared to the pure Pebax®1657 membrane. Polymer chain rigidification at high filler loading is supposed to be a reason for the reduced permeability. The composite membranes prepared in this work show better performance in terms of permeance and selectivity when compared with asymmetric mixed matrix membranes described in the recent literature. Overall, the ZIF 7/Pebax mixed matrix membranes show a high performance for CO2 separation from methane and other gas streams. They are easy to

  17. Southern Ocean carbon-wind stress feedback

    Science.gov (United States)

    Bronselaer, Ben; Zanna, Laure; Munday, David R.; Lowe, Jason

    2018-02-01

    The Southern Ocean is the largest sink of anthropogenic carbon in the present-day climate. Here, Southern Ocean pCO2 and its dependence on wind forcing are investigated using an equilibrium mixed layer carbon budget. This budget is used to derive an expression for Southern Ocean pCO2 sensitivity to wind stress. Southern Ocean pCO2 is found to vary as the square root of area-mean wind stress, arising from the dominance of vertical mixing over other processes such as lateral Ekman transport. The expression for pCO2 is validated using idealised coarse-resolution ocean numerical experiments. Additionally, we show that increased (decreased) stratification through surface warming reduces (increases) the sensitivity of the Southern Ocean pCO2 to wind stress. The scaling is then used to estimate the wind-stress induced changes of atmospheric pCO_2 in CMIP5 models using only a handful of parameters. The scaling is further used to model the anthropogenic carbon sink, showing a long-term reversal of the Southern Ocean sink for large wind stress strength.

  18. Enthalpy generation from mixing in hohlraum-driven targets

    Science.gov (United States)

    Amendt, Peter; Milovich, Jose

    2016-10-01

    The increase in enthalpy from the physical mixing of two initially separated materials is analytically estimated and applied to ICF implosions and gas-filled hohlraums. Pressure and temperature gradients across a classical interface are shown to be the origin of enthalpy generation from mixing. The amount of enthalpy generation is estimated to be on the order of 100 Joules for a 10 micron-scale annular mixing layer between the solid deuterium-tritium fuel and the undoped high-density carbon ablator of a NIF-scale implosion. A potential resonance is found between the mixing layer thickness and gravitational (Cs2/ g) and temperature-gradient scale lengths, leading to elevated enthalpy generation. These results suggest that if mixing occurs in current capsule designs for the National Ignition Facility, the ignition margin may be appreciably eroded by the associated enthalpy of mixing. The degree of enthalpy generation from mixing of high- Z hohlraum wall material and low- Z gas fills is estimated to be on the order of 100 kJ or more for recent NIF-scale hohlraum experiments, which is consistent with the inferred missing energy based on observed delays in capsule implosion times. Work performed under the auspices of Lawrence Livermore National Security, LLC (LLNS) under Contract No. DE-AC52-07NA27344.

  19. Functionalized carbon nanotubes mixed matrix membranes of polymers of intrinsic microporosity for gas separation.

    Science.gov (United States)

    Khan, Muntazim Munir; Filiz, Volkan; Bengtson, Gisela; Shishatskiy, Sergey; Rahman, Mushfequr; Abetz, Volker

    2012-09-06

    The present work reports on the gas transport behavior of mixed matrix membranes (MMM) which were prepared from multi-walled carbon nanotubes (MWCNTs) and dispersed within polymers of intrinsic microporosity (PIM-1) matrix. The MWCNTs were chemically functionalized with poly(ethylene glycol) (PEG) for a better dispersion in the polymer matrix. MMM-incorporating functionalized MWCNTs (f-MWCNTs) were fabricated by dip-coating method using microporous polyacrylonitrile membrane as a support and were characterized for gas separation performance. Gas permeation measurements show that MMM incorporated with pristine or functionalized MWCNTs exhibited improved gas separation performance compared to pure PIM-1. The f-MWCNTs MMM show better performance in terms of permeance and selectivity in comparison to pristine MWCNTs. The gas permeances of the derived MMM are increased to approximately 50% without sacrificing the selectivity at 2 wt.% of f-MWCNTs' loading. The PEG groups on the MWCNTs have strong interaction with CO2 which increases the solubility of polar gas and limit the solubility of nonpolar gas, which is advantageous for CO2/N2 selectivity. The addition of f-MWCNTs inside the polymer matrix also improved the long-term gas transport stability of MMM in comparison with PIM-1. The high permeance, selectivity, and long term stability of the fabricated MMM suggest that the reported approach can be utilized in practical gas separation technology.

  20. Carbon potential measurement on some actinide carbides

    International Nuclear Information System (INIS)

    Anthonysamy, S.; Ananthasivan, K.; Kaliappan, I.; Chandramouli, V.; Vasudeva Rao, P.R.; Mathews, C.K.; Jacob, K.T.

    1994-01-01

    Uranium-Plutonium mixed carbides with a Pu/(U+Pu) ratio of 0.55 are to be used as the fuel in the Fast Breeder Test Reactor (FBTR) at Kalpakkam, India. Carburization of the stainless steel clad by this fuel is determined by its carbon potential. Because the carbon potential of this fuel composition is not available in the literature, it was measured by the methane-hydrogen gas equilibration technique. The sample was equilibrated with purified hydrogen and the equilibrium methane-to-hydrogen ratio in the gas phase was measured with a flame ionization detector. The carbon potential of the ThC-ThC 2 as well as Mo-Mo 2 C system, which is an important binary in the actinide-fission product-carbon systems, were also measured by this technique in the temperature range 973 to 1,173 K. The data for the Mo-Mo 2 C system are in agreement with values reported in the literature. The results for the ThC-ThC 2 system are different from estimated values with large uncertainty limits given in the literature. The data on (U, Pu) mixed carbides indicates the possibility of stainless steel clad attack under isothermal equilibrium conditions

  1. Molten salt destruction process for mixed wastes

    International Nuclear Information System (INIS)

    Upadhye, R.S.; Wilder, J.G.; Karlsen, C.E.

    1993-04-01

    We are developing an advanced two-stage process for the treatment of mixed wastes, which contain both hazardous and radioactive components. The wastes, together with an oxidant gas, such as air, are injected into a bed of molten salt comprising a mixture of sodium-, potassium-, and lithium-carbonates, with a melting point of about 580 degree C. The organic constituents of the mixed waste are destroyed through the combined effect of pyrolysis and oxidation. Heteroatoms. such as chlorine, in the mixed waste form stable salts, such as sodium chloride, and are retained in the melt. The radioactive actinides in the mixed waste are also retained in the melt because of the combined action of wetting and partial dissolution. The original process, consists of a one-stage unit, operated at 900--1000 degree C. The advanced two-stage process has two stages, one for pyrolysis and one for oxidation. The pyrolysis stage is designed to operate at 700 degree C. The oxidation stage can be operated at a higher temperature, if necessary

  2. Substrate inhibition kinetics of phenol degradation by binary mixed ...

    African Journals Online (AJOL)

    Steady states of a continuous culture with an inhibitory substrate were used to estimate kinetic parameters under substrate limitation (chemo stat operation). Mixed cultures of an indigenous Pseudomonas fluorescence and Pseudomonas aeruginosa were grown in continuous culture on phenol as the sole source of carbon ...

  3. Alternative solution model for the ternary carbonate system CaCO3 - MgCO3 - FeCO3 - II. Calibration of a combined ordering model and mixing model

    Science.gov (United States)

    McSwiggen, P.L.

    1993-01-01

    Earlier attempts at solution models for the ternary carbonate system have been unable to adequately accommodate the cation ordering which occurs in some of the carbonate phases. The carbonate solution model of this study combines a Margules type of interaction model with a Bragg-Williams type of ordering model. The ordering model determines the equilibrium state of order for a crystal, from which the cation distribution within the lattice can be obtained. The interaction model addresses the effect that mixing different cation species within a given cation layer has on the total free energy of the system. An ordering model was derived, based on the Bragg-Williams approach; it is applicable to ternary systems involving three cations substituting on two sites, and contains three ordering energy parameters (WCaMg, WCaFe, and WCaMgFe). The solution model of this study involves six Margules-type interaction parameters (W12, W21, W13, W31, W23, and W32). Values for the two sets of energy parameters were calculated from experimental data and from compositional relationships in natural assemblages. ?? 1993 Springer-Verlag.

  4. FACIES PARTITIONING AND SEQUENCE STRATIGRAPHY OF A MIXED SILICICLASTIC-CARBONATE RAMP STACK IN THE GELASIAN OF SICILY (S ITALY: A POTENTIAL MODEL FOR ICEHOUSE, DISTALLY-STEEPENED HETEROZOAN RAMPS

    Directory of Open Access Journals (Sweden)

    FRANCESCO MASSARI

    2012-11-01

    Full Text Available The Gelasian succession of the Capodarso area (Enna-Caltanissetta basin, Sicily, Italy consists of an offlapping stack of cycles composed of siliciclastic units passing to carbonate heterozoan, clino-stratified wedges, developed from a growing positive tectonic structure. Identification of a number of facies tracts, based on sedimentary facies, biofacies and taphofacies, provided important information about the differentiation and characterisation of systems tracts and key stratal surfaces of sequence stratigraphy. The bulk of carbonate wedges are interpreted as representing the rapid falling-stage progradation of distally steepened ramps. The inferred highest rate of carbonate production during forced regressions was concomitant with active downramp resedimentation by storm-driven downwelling flows, leading to storing of most carbonate sediment on the ramp slope as clino-beds of the prograding bodies. Comparison of the Capodarso ramps with other icehouse carbonate ramps, with particular regard to the Mediterranean Plio-Pleistocene, provides clues for defining some common features. These are inferred to include: (1 brief, rapid episodes of progradation concomitant with orbitally-forced sea-level changes, resulting in limited ramp width; (2 preferential fostering of growth and downramp resedimentation of heterozoan carbonates during glacial hemicycles marked by enhanced atmospheric and marine circulation; (3 building out from positive features of entirely submerged distally-steepened ramps with storm-wave-graded profile and distinctive clinoforms; (4 ramp stacks generally consisting of mixed clastic-carbonate sequences showing an ordered spectrum of distinct frequencies; (5 rapid, continuous changes in environmental parameters, leading to the short-lived persistence of faunal communities, climax communities generally having insufficient time to form. 

  5. Nonstationary porosity evolution in mixing zone in coastal carbonate aquifer using an alternative modeling approach.

    Science.gov (United States)

    Laabidi, Ezzeddine; Bouhlila, Rachida

    2015-07-01

    In the last few decades, hydrogeochemical problems have benefited from the strong interest in numerical modeling. One of the most recognized hydrogeochemical problems is the dissolution of the calcite in the mixing zone below limestone coastal aquifer. In many works, this problem has been modeled using a coupling algorithm between a density-dependent flow model and a geochemical model. A related difficulty is that, because of the high nonlinearity of the coupled set of equations, high computational effort is needed. During calcite dissolution, an increase in permeability can be identified, which can induce an increase in the penetration of the seawater into the aquifer. The majority of the previous studies used a fully coupled reactive transport model in order to model such problem. Romanov and Dreybrodt (J Hydrol 329:661-673, 2006) have used an alternative approach to quantify the porosity evolution in mixing zone below coastal carbonate aquifer at steady state. This approach is based on the analytic solution presented by Phillips (1991) in his book Flow and Reactions in Permeable Rock, which shows that it is possible to decouple the complex set of equation. This equation is proportional to the square of the salinity gradient, which can be calculated using a density driven flow code and to the reaction rate that can be calculated using a geochemical code. In this work, this equation is used in nonstationary step-by-step regime. At each time step, the quantity of the dissolved calcite is quantified, the change of porosity is calculated, and the permeability is updated. The reaction rate, which is the second derivate of the calcium equilibrium concentration in the equation, is calculated using the PHREEQC code (Parkhurst and Apello 1999). This result is used in GEODENS (Bouhlila 1999; Bouhlila and Laabidi 2008) to calculate change of the porosity after calculating the salinity gradient. For the next time step, the same protocol is used but using the updated porosity

  6. Indoor and outdoor urban atmospheric CO2: Stable carbon isotope constraints on mixing and mass balance

    International Nuclear Information System (INIS)

    Yanes, Yurena; Yapp, Crayton J.

    2010-01-01

    Research highlights: → 13 C of indoor CO 2 indicates proportion of C 4 -derived carbon in occupants' diet. → Flux balance model for ventilated rooms shows rapid approach to CO 2 steady-state. → From extant indoor CO 2 data more dietary C 4 carbon in American than European diets. → Local outdoor urban CO 2 increase of 17 ppm in ten years, no change in average 13 C. - Abstract: From July to November 2009, concentrations of CO 2 in 78 samples of ambient air collected in 18 different interior spaces on a university campus in Dallas, Texas (USA) ranged from 386 to 1980 ppm. Corresponding δ 13 C values varied from -8.9 per mille to -19.4 per mille. The CO 2 from 22 samples of outdoor air (also collected on campus) had a more limited range of concentrations from 385 to 447 ppm (avg. = 408 ppm), while δ 13 C values varied from -10.1 per mille to -8.4 per mille (avg.=-9.0 per mille). In contrast to ambient indoor and outdoor air, the concentrations of CO 2 exhaled by 38 different individuals ranged from 38,300 to 76,200 ppm (avg. = 55,100 ppm), while δ 13 C values ranged from -24.8 per mille to -17.7 per mille (avg. = -21.8 per mille). The residence times of the total air in the interior spaces of this study appear to have been on the order of 10 min with relatively rapid approaches (∼30 min) to steady-state concentrations of ambient CO 2 gas. Collectively, the δ 13 C values of the indoor CO 2 samples were linearly correlated with the reciprocal of CO 2 concentration, exhibiting an intercept of -21.8 per mille, with r 2 = 0.99 and p 2 data representing 18 interior spaces (with varying numbers of occupants), and the coincidence of the intercept (-21.8 per mille) with the average δ 13 C value for human-exhaled CO 2 demonstrates simple mixing between two inputs: (1) outdoor CO 2 introduced to the interior spaces by ventilation systems, and (2) CO 2 exhaled by human occupants of those spaces. If such simple binary mixing is a common feature of interior spaces, it

  7. A mixing-model approach to quantifying sources of organic matter to salt marsh sediments

    Science.gov (United States)

    Bowles, K. M.; Meile, C. D.

    2010-12-01

    Salt marshes are highly productive ecosystems, where autochthonous production controls an intricate exchange of carbon and energy among organisms. The major sources of organic carbon to these systems include 1) autochthonous production by vascular plant matter, 2) import of allochthonous plant material, and 3) phytoplankton biomass. Quantifying the relative contribution of organic matter sources to a salt marsh is important for understanding the fate and transformation of organic carbon in these systems, which also impacts the timing and magnitude of carbon export to the coastal ocean. A common approach to quantify organic matter source contributions to mixtures is the use of linear mixing models. To estimate the relative contributions of endmember materials to total organic matter in the sediment, the problem is formulated as a constrained linear least-square problem. However, the type of data that is utilized in such mixing models, the uncertainties in endmember compositions and the temporal dynamics of non-conservative entitites can have varying affects on the results. Making use of a comprehensive data set that encompasses several endmember characteristics - including a yearlong degradation experiment - we study the impact of these factors on estimates of the origin of sedimentary organic carbon in a saltmarsh located in the SE United States. We first evaluate the sensitivity of linear mixing models to the type of data employed by analyzing a series of mixing models that utilize various combinations of parameters (i.e. endmember characteristics such as δ13COC, C/N ratios or lignin content). Next, we assess the importance of using more than the minimum number of parameters required to estimate endmember contributions to the total organic matter pool. Then, we quantify the impact of data uncertainty on the outcome of the analysis using Monte Carlo simulations and accounting for the uncertainty in endmember characteristics. Finally, as biogeochemical processes

  8. Optimal Energy Mix with Renewable Portfolio Standards in Korea

    Directory of Open Access Journals (Sweden)

    Zong Woo Geem

    2016-05-01

    Full Text Available Korea is a heavily energy-dependent country whose primary energy consumption ranks ninth in the world. However, at the same time, it promised to reduce carbon emission and planned to use more renewable energy. Thus, the objective of this study is to propose an optimal energy mix planning model in electricity generation from various energy sources, such as gas, coal, nuclear, hydro, wind, photovoltaic, and biomass, which considers more renewable and sustainable portions by imposing governmental regulation named renewable portfolio standard (RPS. This optimization model minimizes various costs such as construction cost, operation and management cost, fuel cost, and carbon emission cost while satisfying minimal demand requirement, maximal annual installation potential, and renewable portfolio standard constraints. Results showed that this optimization model could successfully generate energy mix plan from 2012 to 2030 while minimizing the objective costs and satisfying all the constraints. Therefore, this optimization model contributes more efficient and objective method to the complex decision-making process with a sustainability option. This proposed energy mix model is expected to be applied not only to Korea, but also to many other countries in the future for more economical planning of their electricity generation while affecting climate change less.

  9. Iron-tellurium-selenium mixed oxide catalysts for the selective oxidation of propylene to acrolein

    International Nuclear Information System (INIS)

    Patel, B.M.; Price, G.L.

    1990-01-01

    This paper reports on iron-tellurium-selenium mixed oxide catalysts prepared by coprecipitation from aqueous solution investigated for the propylene to acrolein reaction in the temperature range 543-773 K. Infrared spectroscopy, electron dispersive X-ray analysis, X-ray diffraction, and isotopic tracer techniques have also been employed to characterize this catalytic system. Properties of the Fe-Te-Se mixed oxide catalysts have been compared with Fe-Te mixed oxides in an effort to deduce the functionality of Se. The selenium in the Fe-Te-Se-O catalyst has been found to be the hydrocarbon activating site. The activation energies for the acrolein and carbon dioxide formation are 71 and 54 kJ/mol, respectively. Reactions carried out with 18 O 2 have shown lattice oxygen to be primarily responsible for the formation of both acrolein and carbon dioxide. The initial and rate-determining step for acrolein formation is hydrogen abstraction as determined by an isotope effect associated with the C 3 D 6 reaction. No isotope effect is observed for carbon dioxide formation from C 3 D 6 suggesting that CO 2 is formed by parallel, not consecutive, oxidation of propylene

  10. Vibrationally Excited Carbon Monoxide Produced via a Chemical Reaction Between Carbon Vapor and Oxygen

    Science.gov (United States)

    Jans, Elijah R.; Eckert, Zakari; Frederickson, Kraig; Rich, Bill; Adamovich, Igor V.

    2017-06-01

    Measurements of the vibrational distribution function of carbon monoxide produced via a reaction between carbon vapor and molecular oxygen has shown a total population inversion on vibrational levels 4-7. Carbon vapor, produced using an arc discharge to sublimate graphite, is mixed with an argon oxygen flow. The excited carbon monoxide is vibrationally populated up to level v=14, at low temperatures, T=400-450 K, in a collision-dominated environment, 15-20 Torr, with total population inversions between v=4-7. The average vibrational energy per CO molecule formed by the reaction is 0.6-1.2 eV/molecule, which corresponds to 10-20% of the reaction enthalpy. Kinetic modeling of the flow reactor, including state specific vibrational processes, was performed to infer the vibrational distribution of the products of the reaction. The results show viability of developing of a new chemical CO laser from the reaction of carbon vapor and oxygen.

  11. Particle-Resolved Modeling of Aerosol Mixing State in an Evolving Ship Plume

    Science.gov (United States)

    Riemer, N. S.; Tian, J.; Pfaffenberger, L.; Schlager, H.; Petzold, A.

    2011-12-01

    The aerosol mixing state is important since it impacts the particles' optical and CCN properties and thereby their climate impact. It evolves continuously during the particles' residence time in the atmosphere as a result of coagulation with other particles and condensation of secondary aerosol species. This evolution is challenging to represent in traditional aerosol models since they require the representation of a multi-dimensional particle distribution. While modal or sectional aerosol representations cannot practically resolve the aerosol mixing state for more than a few species, particle-resolved models store the composition of many individual aerosol particles directly. They thus sample the high-dimensional composition state space very efficiently and so can deal with tens of species, fully resolving the mixing state. Here we use the capabilities of the particle-resolved model PartMC-MOSAIC to simulate the evolution of particulate matter emitted from marine diesel engines and compare the results to aircraft measurements made in the English Channel in 2007 as part of the European campaign QUANTIFY. The model was initialized with values of gas concentrations and particle size distributions and compositions representing fresh ship emissions. These values were obtained from a test rig study in the European project HERCULES in 2006 using a serial four-stroke marine diesel engine operating on high-sulfur heavy fuel oil. The freshly emitted particles consisted of sulfate, black carbon, organic carbon and ash. We then tracked the particle population for several hours as it evolved undergoing coagulation, dilution with the background air, and chemical transformations in the aerosol and gas phase. This simulation was used to compute the evolution of CCN properties and optical properties of the plume on a per-particle basis. We compared our results to size-resolved data of aged ship plumes from the QUANTIFY Study in 2007 and showed that the model was able to reproduce

  12. Materials dependence of mixed gas plasticization behavior in asymmetric membranes

    NARCIS (Netherlands)

    Visser, Tymen; Masetto, N.; Wessling, Matthias

    2007-01-01

    The mass transport of asymmetric membranes for the separation of carbon dioxide/methane mixtures is determined by competitive sorption and plasticization. With increasing feed pressure in mixed gas experiments, the selectivity decreases due to both effects. Distinction whether one or the other

  13. Metabolic modeling of mixed substrate uptake for polyhydroxyalkanoate (PHA) production

    NARCIS (Netherlands)

    Jiang, Y.; Hebly, M.; Kleerebezem, R.; Muyzer, G.; van Loosdrecht, M.C.M.

    2011-01-01

    Polyhydroxyalkanoate (PHA) production by mixed microbial communities can be established in a two-stage process, consisting of a microbial enrichment step and a PHA accumulation step. In this study, a mathematical model was constructed for evaluating the influence of the carbon substrate composition

  14. Gadolinium DTPA-monoamide complexes incorporated into mixed micelles as possible MRI contrast agents

    OpenAIRE

    Parac-Vogt, Tatjana; Kimpe, Kristof; Laurent, Sophie; Pierart, Corinne; Vander Elst, Luce; Muller, Robert N.; Binnemans, Koen

    2004-01-01

    Four monoamide derivatives of Gd-DTPA with alkyl chains consisting of 12, 14, 16, or 18 carbon atoms were synthesized. The gadolinium(III) complexes with chain lengths of 14, 16 or 18 carbon atoms were efficiently incorporated into mixed micelles whereas the complex with a chain length of 12 carbon atoms was not incorporated into a micellar structure. The size distribution of the micelles was measured by photon correlation spectroscopy. The mean sizes of the micelles for all the complexes lay...

  15. Carbon mineralization in surface and subsurface soils in a subtropical mixed forest in central China

    Science.gov (United States)

    Liu, F.; Tian, Q.

    2014-12-01

    About a half of soil carbon is stored in subsurface soil horizons, their dynamics have the potential to significantly affect carbon balancing in terrestrial ecosystems. However, the main factors regulating subsurface soil carbon mineralization are poorly understood. As affected by mountain humid monsoon, the subtropical mountains in central China has an annual precipitation of about 2000 mm, which causes strong leaching of ions and nutrition. The objectives of this study were to monitor subsurface soil carbon mineralization and to determine if it is affected by nutrient limitation. We collected soil samples (up to 1 m deep) at three locations in a small watershed with three soil layers (0-10 cm, 10-30 cm, below 30 cm). For the three layers, soil organic carbon (SOC) ranged from 35.8 to 94.4 mg g-1, total nitrogen ranged from 3.51 to 8.03 mg g-1, microbial biomass carbon (MBC) ranged from 170.6 to 718.4 μg g-1 soil. We measured carbon mineralization with the addition of N (100 μg N/g soil), P (50 μg P/g soil), and liable carbon (glucose labeled by 5 atom% 13C, at five levels: control, 10% MBC, 50% MBC, 100% MBC, 200% MBC). The addition of N and P had negligible effects on CO2 production in surface soil layers; in the deepest soil layer, the addition of N and P decreased CO2 production from 4.32 to 3.20 μg C g-1 soil carbon h-1. Glucose addition stimulated both surface and subsurface microbial mineralization of SOC, causing priming effects. With the increase of glucose addition rate from 10% to 200% MBC, the primed mineralization rate increased from 0.19 to 3.20 μg C g-1 soil carbon h-1 (fifth day of glucose addition). The magnitude of priming effect increased from 28% to 120% as soil layers go deep compare to the basal CO2 production (fifth day of 200% MBC glucose addition, basal CO2 production rate for the surface and the deepest soil was 11.17 and 2.88 μg C g-1 soil carbon h-1). These results suggested that the mineralization of subsurface carbon is more

  16. Graphene-based carbons as supercapacitor electrodes with bicontinuous, porous polyacrylonitrile

    Science.gov (United States)

    Kim, Bit-Na; Yang, Young Suk; You, In-Kyu

    2017-07-01

    In this study, we fabricated a bicontinuous carbon structure (BCS) with high porosity and a loosely connected framework structure. The role of the BCS is to support a concrete supercapacitor active electrode structure. Poly(acrylonitrile) was used as a precursor for the BCS material, which was a porous polymer monolith carbonized by heat treatment (at 1100 °C). The BCS was prepared by mixing with an active material, graphene or an activated carbon. The mixed materials were used as an electrode material in a supercapacitor. The BCS13 + AC sample (∼107.5 F/g) showed a higher specific capacitance than the commercial activated carbon cell (∼76 F/g). The BCS13 + graphene sample (∼75 F/g) also exhibited a higher specific capacitance than the graphene cell (∼49 F/g). This BCS monolith had many macro- and micropores in its structure, enabling fast electrolyte ion movement and excellent electrochemical performance with a low equivalent series resistance (ESR).

  17. Catalytic Enhancement of Solid Carbon Oxidation in HDCFCs

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Ippolito, Davide; Kammer Hansen, Kent

    2014-01-01

    data as a function of temperature, anode and cathode atmospheres, and their flow rates are discussed. In the anode chamber, catalysts are mixed with the carbon-carbonate mixture. These catalysts include various manganese oxides (MnO2, Mn2O3, and Mn3O4, Fig. 1) and doped-ceria (CeO2, Ce1-xGdxO2, Ce1-x...

  18. Integrating terrestrial through aquatic processing of water, carbon and nitrogen over hot, cold and lukewarm moments in mixed land use catchments

    Science.gov (United States)

    Band, L. E.; Lin, L.; Duncan, J. M.

    2017-12-01

    A major challenge in understanding and managing freshwater volumes and quality in mixed land use catchments is the detailed heterogeneity of topography, soils, canopy, and inputs of water and biogeochemicals. The short space and time scale dynamics of sources, transport and processing of water, carbon and nitrogen in natural and built environments can have a strong influence on the timing and magnitude of watershed runoff and nutrient production, ecosystem cycling and export. Hydroclimate variability induces a functional interchange of terrestrial and aquatic environments across their transition zone with the temporal and spatial expansion and contraction of soil wetness, standing and flowing water over seasonal, diurnal and storm event time scales. Variation in sources and retention of nutrients at these scales need to be understood and represented to design optimal mitigation strategies. This paper discusses the conceptual framework used to design both simulation and measurement approaches, and explores these dynamics using an integrated terrestrial-aquatic watershed model of coupled water-carbon-nitrogen processes at resolutions necessary to resolve "hot spot/hot moment" phenomena in two well studied catchments in Long Term Ecological Research sites. The potential utility of this approach for design and assessment of urban green infrastructure and stream restoration strategies is illustrated.

  19. Atmospheric carbon tetrachloride in rural background and industry surrounded urban areas in Northern Iberian Peninsula: Mixing ratios, trends, and potential sources

    International Nuclear Information System (INIS)

    Blas, Maite de; Uria-Tellaetxe, Iratxe; Gomez, Maria Carmen; Navazo, Marino; Alonso, Lucio; García, Jose Antonio; Durana, Nieves; Iza, Jon; Ramón, Jarol Derley

    2016-01-01

    Latest investigations on atmospheric carbon tetrachloride (CTC) are focused on its ozone depleting potential, adverse effects on the human health, and radiative efficiency and Global Warming Potential as a greenhouse gas. CTC mixing ratios have been thoroughly studied since its restriction under the Montreal Protocol, mostly in remote areas with the aim of reporting long-term trends after its banning. The observed decrease of the CTC background mixing ratio, however, was not as strong as expected. In order to explain this behavior CTC lifetime should be adjusted by estimating the relative significance of its sinks and by identifying ongoing potential sources. Looking for possible sources, CTC was measured with high-time resolution in two sites in Northern Spain, using auto-GC systems and specifically developed acquisition and processing methodologies. The first site, Bilbao, is an urban area influenced by the surrounding industry, where measurements were performed with GC–MSD for a one-year period (2007–2008). The second site, at Valderejo Natural Park (VNP), is a rural background area where measurements were carried out with GC-FID and covering CTC data a nonsuccessive five-year period (2003–2005, 2010–2011, and 2014–2015 years). Median yearly CTC mixing ratios were slightly higher in the urban area (120 pptv) than in VNP (80–100 pptv). CTC was reported to be well mixed in the atmosphere and no sources were noticed to impact the rural site. The observed long-term trend in VNP was in agreement with the estimated global CTC emissions. In the urban site, apart from industrial and commercial CTC sources, chlorine-bleach products used as cleaning agents were reported as promotors of indoor sources. - Highlights: • A methodology was developed to measure CTC using GC-MSD and GC-FID. • CTC ongoing sources were noticed in an industry surrounded urban area. • No noticeable nearby CTC sources impacted the rural site. • Long-term CTC trend in agreement

  20. Atmospheric carbon tetrachloride in rural background and industry surrounded urban areas in Northern Iberian Peninsula: Mixing ratios, trends, and potential sources

    Energy Technology Data Exchange (ETDEWEB)

    Blas, Maite de, E-mail: maite.deblas@ehu.eus [School of Engineering of Bilbao, University of the Basque Country UPV/EHU (Spain); Uria-Tellaetxe, Iratxe; Gomez, Maria Carmen [School of Engineering of Bilbao, University of the Basque Country UPV/EHU (Spain); Navazo, Marino [University College of Engineering of Vitoria-Gasteiz, University of the Basque Country UPV/EHU (Spain); Alonso, Lucio; García, Jose Antonio; Durana, Nieves; Iza, Jon; Ramón, Jarol Derley [School of Engineering of Bilbao, University of the Basque Country UPV/EHU (Spain)

    2016-08-15

    Latest investigations on atmospheric carbon tetrachloride (CTC) are focused on its ozone depleting potential, adverse effects on the human health, and radiative efficiency and Global Warming Potential as a greenhouse gas. CTC mixing ratios have been thoroughly studied since its restriction under the Montreal Protocol, mostly in remote areas with the aim of reporting long-term trends after its banning. The observed decrease of the CTC background mixing ratio, however, was not as strong as expected. In order to explain this behavior CTC lifetime should be adjusted by estimating the relative significance of its sinks and by identifying ongoing potential sources. Looking for possible sources, CTC was measured with high-time resolution in two sites in Northern Spain, using auto-GC systems and specifically developed acquisition and processing methodologies. The first site, Bilbao, is an urban area influenced by the surrounding industry, where measurements were performed with GC–MSD for a one-year period (2007–2008). The second site, at Valderejo Natural Park (VNP), is a rural background area where measurements were carried out with GC-FID and covering CTC data a nonsuccessive five-year period (2003–2005, 2010–2011, and 2014–2015 years). Median yearly CTC mixing ratios were slightly higher in the urban area (120 pptv) than in VNP (80–100 pptv). CTC was reported to be well mixed in the atmosphere and no sources were noticed to impact the rural site. The observed long-term trend in VNP was in agreement with the estimated global CTC emissions. In the urban site, apart from industrial and commercial CTC sources, chlorine-bleach products used as cleaning agents were reported as promotors of indoor sources. - Highlights: • A methodology was developed to measure CTC using GC-MSD and GC-FID. • CTC ongoing sources were noticed in an industry surrounded urban area. • No noticeable nearby CTC sources impacted the rural site. • Long-term CTC trend in agreement

  1. Effect of Multiwalled Carbon Nanotubes on the Properties of EPDM/NBR Dissimilar Elastomer Blends

    NARCIS (Netherlands)

    Hoikkanen, M.; Poikelispää, M.; Das, A.; Honkanen, M.; Dierkes, Wilma K.; Vuorinen, J.

    2015-01-01

    In the presence of multiwalled carbon nanotubes (MWCNT), polar nitrile-butadiene rubber (NBR) and nonpolar ethylene propylene diene rubber (EPDM) blends were prepared following a melt mixing method. For the preparation of MWCNT filled EPDM/NBR blends, two mixing methods were used: direct mixing and

  2. Study of the catalytic activity of mixed non-stoichiometric uranium-thorium oxides in carbon monoxide oxidation; Etude de l'activite catalytique des oxydes mixtes d'uranium et de thorium non stoechiometriques dans l'oxydation du monoxyde de carbone

    Energy Technology Data Exchange (ETDEWEB)

    Brau, G [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1969-06-01

    The aim of this work has been to study the catalytic properties of non-stoichiometric uranium-thorium oxides having the general formula U{sub x}Th{sub 1-x}O{sub 2+y}, for the oxidation of carbon monoxide. The preparation of pure, homogeneous, isotropic solids having good structural stability and a surface area as high as possible calls for a strict control of the conditions of preparation of these oxides right from the preparation of 'mother salts': the mixed oxalates U{sub x}Th{sub 1-x}(C{sub 2}O{sub 4}){sub 2}, 2H{sub 2}O. A study has been made of their physico-chemical properties (overall and surface chemical constitution, texture, structure, electrical conductivity), as well as of their adsorption properties with respect to gaseous species occurring in the catalytic reaction. This analysis has made it possible to put forward a reaction mechanism based on successive oxidations and reductions of the active surface by the reactants. A study of the reactions kinetics has confirmed the existence of this oxidation-reduction mechanism which only occurs for oxides having a uranium content of above 0.0014. The carbon dioxide produced by the reaction acts as an inhibitor by blocking the sites on which carbon monoxide can be adsorbed. These non-stoichiometric mixed oxides are a particularly clear example of catalysis by oxygen exchange between the solid and the gas phase. (author) [French] Ce travail a pour but l'etude des proprietes catalytiques des oxydes mixtes d'uranium et de thorium non stoechiometriques de formule generale U{sub x}Th{sub 1-x}O{sub 2+y} dans l'oxydation du monoxyde de carbone. L'obtention de solides purs, homogenes, isotropes, de bonne stabilite structurale et d'aire specifique aussi elevee que possible, exige de controler rigoureusement les conditions de preparation de ces oxydes des l'elaboration de leurs 'ascendants': les oxalates mixtes U{sub x}Th{sub 1-x}(C{sub 2}O{sub 4}){sub 2}, 2H{sub 2}O. Leurs proprietes physico-chimiques (composition

  3. Estimating foliar biochemistry from hyperspectral data in mixed forest canopy

    DEFF Research Database (Denmark)

    Huber Gharib, Silvia; Kneubühler, Mathias; Psomas, Achilleas

    2008-01-01

    data to estimate the foliar concentration of nitrogen, carbon and water in three mixed forest canopies in Switzerland. With multiple linear regression models, continuum-removed and normalized HyMap spectra were related to foliar biochemistry on an individual tree level. The six spectral wavebands used...

  4. Water masses as a unifying framework for understanding the Southern Ocean Carbon Cycle

    Directory of Open Access Journals (Sweden)

    D. Iudicone

    2011-05-01

    Full Text Available The scientific motivation for this study is to understand the processes in the ocean interior controlling carbon transfer across 30° S. To address this, we have developed a unified framework for understanding the interplay between physical drivers such as buoyancy fluxes and ocean mixing, and carbon-specific processes such as biology, gas exchange and carbon mixing. Given the importance of density in determining the ocean interior structure and circulation, the framework is one that is organized by density and water masses, and it makes combined use of Eulerian and Lagrangian diagnostics. This is achieved through application to a global ice-ocean circulation model and an ocean biogeochemistry model, with both components being part of the widely-used IPSL coupled ocean/atmosphere/carbon cycle model.

    Our main new result is the dominance of the overturning circulation (identified by water masses in setting the vertical distribution of carbon transport from the Southern Ocean towards the global ocean. A net contrast emerges between the role of Subantarctic Mode Water (SAMW, associated with large northward transport and ingassing, and Antarctic Intermediate Water (AAIW, associated with a much smaller export and outgassing. The differences in their export rate reflects differences in their water mass formation processes. For SAMW, two-thirds of the surface waters are provided as a result of the densification of thermocline water (TW, and upon densification this water carries with it a substantial diapycnal flux of dissolved inorganic carbon (DIC. For AAIW, principal formatin processes include buoyancy forcing and mixing, with these serving to lighten CDW. An additional important formation pathway of AAIW is through the effect of interior processing (mixing, including cabelling that serve to densify SAMW.

    A quantitative evaluation of the contribution of mixing, biology and gas exchange to the DIC evolution per water mass reveals that

  5. Effective enhancement of gas separation performance in mixed matrix membranes using core/shell structured multi-walled carbon nanotube/graphene oxide nanoribbons

    Science.gov (United States)

    Xue, Qingzhong; Pan, Xinglong; Li, Xiaofang; Zhang, Jianqiang; Guo, Qikai

    2017-02-01

    Novel core/shell structured multi-walled carbon nanotube/graphene oxide nanoribbons (MWCNT@GONRs) nanohybrids were successfully prepared using a modified chemical longitudinal unzipping method. Subsequently, the MWCNT@GONRs nanohybrids were used as fillers to enhance the gas separation performance of polyimide based mixed matrix membranes (MMMs). It is found that MMMs concurrently exhibited higher gas selectivity and higher gas permeability compared to pristine polyimide. The high gas selectivity could be attributed to the GONRs shell, which provided a selective barrier and large gas adsorbed area, while the high gas permeability resulted from the hollow structured MWCNTs core with smooth internal surface, which acted as a rapid transport channel. MWCNT@GONRs could be promising candidates to improve gas separation performance of MMMs due to the unique microstructures, ease of synthesis and low filling loading.

  6. Volatility and mixing states of ultrafine particles from biomass burning

    International Nuclear Information System (INIS)

    Maruf Hossain, A.M.M.; Park, Seungho; Kim, Jae-Seok; Park, Kihong

    2012-01-01

    Highlights: ► Size distribution, volatility, and mixing states of ultrafine particles emitted from rice straw, oak, and pine burning under different burning conditions were investigated. ► Smoldering combustion emitted larger mode particles in higher numbers than smaller mode particles, while the converse was true for flaming combustion. ► While the flaming combustion and open burning results imply there is internal mixing of OC and BC, smoldering combustion in rice straw produced ultrafine particles devoid of BC. ► Mixing state of ultrafine particles from biomass burning can alter the single scattering albedo, and might even change the sign of radiative forcing. - Abstract: Fine and ultrafine carbonaceous aerosols produced from burning biomasses hold enormous importance in terms of assessing radiation balance and public health hazards. As such, volatility and mixing states of size-selected ultrafine particles (UFP) emitted from rice straw, oak, and pine burning were investigated by using volatility tandem differential mobility analyzer (VTDMA) technique in this study. Rice straw combustion produced unimodal size distributions of emitted aerosols, while bimodal size distributions from combustions of oak (hardwood) and pine (softwood) were obtained. A nearness of flue gas temperatures and a lower CO ratio of flaming combustion (FC) to smoldering combustion (SC) were characteristic differences found between softwood and hardwood. SC emitted larger mode particles in higher numbers than smaller mode particles, while the converse was true for FC. Rice straw open burning UFPs exhibited a volatilization behavior similar to that between FC and SC. In addition, internal mixing states were observed for size-selected UFPs in all biomasses for all combustion conditions, while external mixing states were only observed for rice straw combustion. Results for FC and open burning suggested there was an internal mixing of volatile organic carbon (OC) and non-volatile core (e

  7. Film fabrication of Fe or Fe3O4 nanoparticles mixed with palmitic acid for vertically aligned carbon nanotube growth using Langmuir-Blodgett technique

    Science.gov (United States)

    Nakamura, Kentaro; Kuriyama, Naoki; Takagiwa, Shota; Sato, Taiga; Kushida, Masahito

    2016-03-01

    Vertically aligned carbon nanotubes (VA-CNTs) were studied as a new catalyst support for polymer electrolyte fuel cells (PEFCs). Controlling the number density and the diameter of VA-CNTs may be necessary to optimize PEFC performance. As the catalyst for CNT growth, we fabricated Fe or Fe3O4 nanoparticle (NP) films by the Langmuir-Blodgett (LB) technique. The catalyst Fe or Fe3O4 NPs were widely separated by mixing with filler molecules [palmitic acid (C16)]. The number density of VA-CNTs was controlled by varying the ratio of catalyst NPs to C16 filler molecules. The VA-CNTs were synthesized from the catalyst NP-C16 LB films by thermal chemical vapor deposition (CVD) using acetylene gas as the carbon source. The developing solvents used in the LB technique and the hydrogen reduction conditions of CVD were optimized to improve the VA-CNT growth rate. We demonstrate that the proposed method can independently control both the density and the diameter of VA-CNTs.

  8. Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-01-01

    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

  9. Carbon dioxide sequestration by direct mineral carbonation with carbonic acid

    Energy Technology Data Exchange (ETDEWEB)

    O' Connor, W.K.; Dahlin, D.C.; Nilsen, D.N.; Walters, R.P.; Turner, P.C.

    2000-07-01

    The Albany Research Center (ARC) of the US Department 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. 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 and member (mg{sub 2}SiO{sub 4})], or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. This slurry is reacted with supercritical carbon dioxide (CO{sub 2}) to produce magnesite (MgCO{sub 3}). The CO{sub 2} is dissolved in water to form carbonic acid (H{sub 2}CO{sub 3}), which dissociates to H{sup +} and HCO{sub 3}{sup {minus}}. The H{sup +} reacts with the mineral, liberating Mg{sup 2+} 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 CO{sub 2} 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 CO{sub 2} (P{sub CO{sub 2}}) of 115 atm. Recent tests using a bicarbonate solution, under identical reaction conditions, have achieved roughly 83% conversion of heat treated serpentine

  10. The three pillar strategy for power generation mix - An analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kehlhofer, Rolf; Hatt, Stefan

    2010-09-15

    Low carbon intensity, load following capability and least cost production are the requirements for a successful energy generation mix. This paper presents an analysis of an optimized mix of technologies 'fulfilling the above criteria' based on the energy production portfolio of a number of key countries. The subjects covered include: - comparison of different production technologies (including future costs of emissions) - grid requirements for flexible and dispatchable variable production capabilities - possibilities and limitations of energy production from renewables - why improved overall energy efficiency leads to higher consumption of electricity.

  11. Distribution of Carbon Dioxide Produced by People in a Room:

    DEFF Research Database (Denmark)

    Naydenov, Kiril Georgiev; Baránková, Petra; Sundell, Jan

    2004-01-01

    Carbon dioxide exhaled by people can be used as a tracer gas for air change measurements in homes. Good mixing of tracer gas with room air is a necessary condition to obtain accurate results. However, the use of fans to ensure mixing is inconvenient. The natural room distribution of metabolic CO2...

  12. Experimental simulation of magma-carbonate interaction beneath Mt. Vesuvius, Italy

    Science.gov (United States)

    Jolis, E. M.; Freda, C.; Troll, V. R.; Deegan, F. M.; Blythe, L. S.; McLeod, C. L.; Davidson, J. P.

    2013-11-01

    We simulated the process of magma-carbonate interaction beneath Mt. Vesuvius in short duration piston-cylinder experiments under controlled magmatic conditions (from 0 to 300 s at 0.5 GPa and 1,200 °C), using a Vesuvius shoshonite composition and upper crustal limestone and dolostone as starting materials. Backscattered electron images and chemical analysis (major and trace elements and Sr isotopes) of sequential experimental products allow us to identify the textural and chemical evolution of carbonated products during the assimilation process. We demonstrate that melt-carbonate interaction can be extremely fast (minutes), and results in dynamic contamination of the host melt with respect to Ca, Mg and 87Sr/86Sr, coupled with intense CO2 vesiculation at the melt-carbonate interface. Binary mixing between carbonate and uncontaminated melt cannot explain the geochemical variations of the experimental charges in full and convection and diffusion likely also operated in the charges. Physical mixing and mingling driven by exsolving volatiles seems to be a key process to promote melt homogenisation. Our results reinforce hypotheses that magma-carbonate interaction is a relevant and ongoing process at Mt. Vesuvius and one that may operate not only on a geological, but on a human timescale.

  13. Microstructure investigations of Ba-Sr mixed ferrites, using SEM technique

    International Nuclear Information System (INIS)

    Amighian, J.; Mozaffari, M.

    1996-01-01

    A series of isotropic Ba-Sr mixed ferrites were prepared, using a conventional dry technique. The starting materials were hematite by product of Isfahan steel factory, strontium carbonate from Merck company and barium carbonate obtained from local source. The principle phase of the samples was chosen to have a composition in the form of (BaO) sub 1-x (SrO) sub x nFe sub 2 O sub 3, in which x varied between 0 to l and n was varied between 5 to 6. The raw materials were thoroughly mixed and fired in an electrical furnace for 2 hours. They were then milled in an vibrating ball mill, in which the optimum milling time for each sample was obtained. After annealing at 750 degree C, the powders were compacted in a cylindrical die under 5 tons/cm sup 2. The compacts were then mixed with a binder and sintered in air for 10 minutes at their optimum temperatures. Using SEM technique, the microstructure of the samples were investigated. Using a permeameter, the coercive force Hc and remanent induction Br were measured. The microstructures obtained from SEM technique can be used to control the sintering stage in ferrite fabrication

  14. Fluid mixing and the deep biosphere of a fossil Lost City-type hydrothermal system at the Iberia Margin.

    Science.gov (United States)

    Klein, Frieder; Humphris, Susan E; Guo, Weifu; Schubotz, Florence; Schwarzenbach, Esther M; Orsi, William D

    2015-09-29

    Subseafloor mixing of reduced hydrothermal fluids with seawater is believed to provide the energy and substrates needed to support deep chemolithoautotrophic life in the hydrated oceanic mantle (i.e., serpentinite). However, geosphere-biosphere interactions in serpentinite-hosted subseafloor mixing zones remain poorly constrained. Here we examine fossil microbial communities and fluid mixing processes in the subseafloor of a Cretaceous Lost City-type hydrothermal system at the magma-poor passive Iberia Margin (Ocean Drilling Program Leg 149, Hole 897D). Brucite-calcite mineral assemblages precipitated from mixed fluids ca. 65 m below the Cretaceous paleo-seafloor at temperatures of 31.7 ± 4.3 °C within steep chemical gradients between weathered, carbonate-rich serpentinite breccia and serpentinite. Mixing of oxidized seawater and strongly reducing hydrothermal fluid at moderate temperatures created conditions capable of supporting microbial activity. Dense microbial colonies are fossilized in brucite-calcite veins that are strongly enriched in organic carbon (up to 0.5 wt.% of the total carbon) but depleted in (13)C (δ(13)C(TOC) = -19.4‰). We detected a combination of bacterial diether lipid biomarkers, archaeol, and archaeal tetraethers analogous to those found in carbonate chimneys at the active Lost City hydrothermal field. The exposure of mantle rocks to seawater during the breakup of Pangaea fueled chemolithoautotrophic microbial communities at the Iberia Margin, possibly before the onset of seafloor spreading. Lost City-type serpentinization systems have been discovered at midocean ridges, in forearc settings of subduction zones, and at continental margins. It appears that, wherever they occur, they can support microbial life, even in deep subseafloor environments.

  15. A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

    Directory of Open Access Journals (Sweden)

    Waris Obitayo

    2012-01-01

    Full Text Available The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.

  16. Laser synthesis of a copper–single-walled carbon nanotube nanocomposite via molecular-level mixing and non-equilibrium solidification

    International Nuclear Information System (INIS)

    Tu, Jay F; Rajule, Nilesh; Molian, Pal; Liu, Yi

    2016-01-01

    A copper–single-walled carbon nanotube (Cu–SWCNT) metal nanocomposite could be an ideal material if it can substantially improve the strength of copper while preserving the metal’s excellent thermal and electrical properties. However, synthesis of such a nanocomposite is highly challenging, because copper and SWCNTs do not form intermetallic compounds and are insoluble; as a result, there are serious issues regarding wettability and fine dispersion of SWCNTs within the copper matrix. In this paper we present a novel wet process, called the laser surface implantation process (LSI), to synthesize Cu–SWCNT nanocomposites by mixing SWCNTs into molten copper. The LSI process includes drilling several microholes on a copper substrate, filling the microholes with SWCNTs suspended in solution, and melting the copper substrate to create a micro-well of molten copper. The molten copper advances radially outward to engulf the microholes with pre-deposited SWCNTs to form the Cu–SWCNT implant upon solidification. Rapid and non-equilibrium solidification is achieved due to copper’s excellent heat conductivity, so that SWCNTs are locked in position within the copper matrix without agglomerating into large clusters. This wet process is very different from the typical dry processes used in powder metallurgy. Very high hardness improvement, up to 527% over pure copper, was achieved, confirmed by micro-indentation tests, with only a 0.23% SWCNT volume fraction. The nanostructure of the nanocomposite was characterized by TEM imaging, energy-dispersive x-ray spectroscopy mapping and spectroscopy measurements. The SWCNTs were found to be finely dispersed within the copper matrix with cluster sizes in the range of nanometers, achieving the goal of molecular-level mixing. (paper)

  17. 3D carbon/cobalt-nickel mixed-oxide hybrid nanostructured arrays for asymmetric supercapacitors.

    Science.gov (United States)

    Zhu, Jianhui; Jiang, Jian; Sun, Zhipeng; Luo, Jingshan; Fan, Zhanxi; Huang, Xintang; Zhang, Hua; Yu, Ting

    2014-07-23

    The electrochemical performance of supercapacitors relies not only on the exploitation of high-capacity active materials, but also on the rational design of superior electrode architectures. Herein, a novel supercapacitor electrode comprising 3D hierarchical mixed-oxide nanostructured arrays (NAs) of C/CoNi3 O4 is reported. The network-like C/CoNi3 O4 NAs exhibit a relatively high specific surface area; it is fabricated from ultra-robust Co-Ni hydroxide carbonate precursors through glucose-coating and calcination processes. Thanks to their interconnected three-dimensionally arrayed architecture and mesoporous nature, the C/CoNi3 O4 NA electrode exhibits a large specific capacitance of 1299 F/g and a superior rate performance, demonstrating 78% capacity retention even when the discharge current jumps by 100 times. An optimized asymmetric supercapacitor with the C/CoNi3 O4 NAs as the positive electrode is fabricated. This asymmetric supercapacitor can reversibly cycle at a high potential of 1.8 V, showing excellent cycling durability and also enabling a remarkable power density of ∼13 kW/kg with a high energy density of ∼19.2 W·h/kg. Two such supercapacitors linked in series can simultaneously power four distinct light-emitting diode indicators; they can also drive the motor of remote-controlled model planes. This work not only presents the potential of C/CoNi3 O4 NAs in thin-film supercapacitor applications, but it also demonstrates the superiority of electrodes with such a 3D hierarchical architecture. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Sorption Characteristics of Mixed Molecules of Glutaraldehyde from Water on Mesoporous Acid-Amine Modified Low-Cost Activated Carbon: Mechanism, Isotherm, and Kinetics

    Directory of Open Access Journals (Sweden)

    Mukosha Lloyd

    2015-01-01

    Full Text Available The environmental discharge of inefficiently treated waste solutions of the strong biocide glutaraldehyde (GA from hospitals has potential toxic impact on aquatic organisms. The adsorption characteristics of mixed polarized monomeric and polymeric molecules of GA from water on mesoporous acid-amine modified low-cost activated carbon (AC were investigated. It was found that the adsorption strongly depended on pH and surface chemistry. In acidic pH, the adsorption mechanism was elaborated to involve chemical sorption of mainly hydroxyl GA monomeric molecules on acidic surface groups, while in alkaline pH, the adsorption was elaborated to involve both chemical and physical sorption of GA polymeric forms having mixed functional groups (aldehyde, carboxyl, and hydroxyl on acidic and amine surface groups. The optimum pH of adsorption was about 12 with significant contribution by cooperative adsorption, elucidated in terms of hydrogen bonding and aldol condensation. Freundlich and Dubinin-Radushkevich models were fitted to isotherm data. The adsorption kinetics was dependent on initial concentration and temperature and described by the Elovich model. The adsorption was endothermic, while the intraparticle diffusion model suggested significant contribution by film diffusion. The developed low-cost AC could be used to supplement the GA alkaline deactivation process for efficient removal of residual GA aquatic toxicity.

  19. Electrochemical treatment of mixed (hazardous and radioactive) wastes

    International Nuclear Information System (INIS)

    Dziewinski, J.; Zawodzinski, C.; Smith, W.H.

    1995-01-01

    Electrochemical treatment technologies for mixed hazardous waste are currently under development at Los Alamos National Laboratory. For a mixed waste containing toxic components such as heavy metals and cyanides in addition to a radioactive component, the toxic components can be removed or destroyed by electrochemical technologies allowing for recovery of the radioactive component prior to disposal of the solution. Mixed wastes with an organic component can be treated by oxidizing the organic compound to carbon dioxide and then recovering the radioactive component. The oxidation can be done directly at the anode or indirectly using an electron transfer mediator. This work describes the destruction of isopropanol, acetone and acetic acid at greater than 90% current efficiency using cobalt +3 or silver +2 as the electron transfer mediator. Also described is the destruction of cellulose based cheesecloth rags with electrochemically generated cobalt +3, at an overall efficiency of approximately 20%

  20. Improvement of acid protease production by a mixed culture of ...

    African Journals Online (AJOL)

    The synthesis of acid protease by Aspergillus oryzae AS3042 was enhanced significantly with the mixed culture of Aspergillus niger SL-09 using solid-state fermentation technique. The influence of carbon sources, nitrogen sources and the addition of phytic acid on acid protease production were investigated. The enzyme ...

  1. Greenhouse gas emissions in Norway: do carbon taxes work?

    International Nuclear Information System (INIS)

    Bruvoll, Annegrete; Larsen, B.M.

    2004-01-01

    During the last decade, Norway has carried out an ambitious climate policy. The main policy tool is a relatively high carbon tax, which was implemented already in 1991. Data for the development in CO 2 emissions since then provide a unique opportunity to evaluate carbon taxes as a policy tool. To reveal the driving forces behind the changes in the three most important climate gases, CO 2 , methane and N 2 O in the period 1990-1999, we decompose the actually observed emissions changes, and use an applied general equilibrium simulation to look into the specific effect of carbon taxes. Although total emissions have increased, we find a significant reduction in emissions per unit of GDP over the period due to reduced energy intensity, changes in the energy mix and reduced process emissions. Despite considerable taxes and price increases for some fuel-types, the carbon tax effect has been modest. While the partial effect from lower energy intensity and energy mix changes was a reduction in CO 2 emissions of 14 percent, the carbon taxes contributed to only 2 percent reduction. This relatively small effect relates to extensive tax exemptions and relatively inelastic demand in the sectors in which the tax is actually implemented

  2. Sources of CO{sub 2} in the Gulf of Trieste (N. Adriatic). Stable Carbon Isotope Evidence

    Energy Technology Data Exchange (ETDEWEB)

    Ogrinc, N.; Zavadlav, S. [Department of Environmental Sciences, Jozef Stefan Institute, Ljubljana (Slovenia); Turk, D. [Department of Oceanography, Dalhousie University, Halifax, Nova Scotia (Canada); Lamont-Doherty Earth Observatory, Earth Institute at Columbia University, Palisades, NY (United States); Faganeli, J. [Marine Biological Station National Institute of Biology, Piran (Slovenia)

    2013-07-15

    In the present study the influence of freshwater intrusions on the net carbon dynamics in the Gulf of Trieste (northern Adriatic Sea) were investigated. Carbonate mineral weathering dominates the inorganic carbon geochemical flux of the N Adriatic rivers and thus the origin of dissolved inorganic carbon (DIC) in the gulf seawater. Based on {delta}{sup 13}C{sub DIC} values and isotopic mass balance it was estimated that rivers represents about 20% of DIC in spring, while the riverine contribution in autumn is less pronounced probably due to intensive water mixing. The results, therefore, suggest that river inputs play a significant role in the carbon cycling in the Gulf of Trieste due to mixing of higher DIC riverine water with lower seawater DIC. The observed higher summer {delta}{sup 13}C{sub DIC} values were due to more pronounced photosynthetic carbon fractionation. (author)

  3. Mixed-culture transcriptome analysis reveals the molecular basis of mixed-culture growth in Streptococcus thermophilus and Lactobacillus bulgaricus.

    Science.gov (United States)

    Sieuwerts, Sander; Molenaar, Douwe; van Hijum, Sacha A F T; Beerthuyzen, Marke; Stevens, Marc J A; Janssen, Patrick W M; Ingham, Colin J; de Bok, Frank A M; de Vos, Willem M; van Hylckama Vlieg, Johan E T

    2010-12-01

    Many food fermentations are performed using mixed cultures of lactic acid bacteria. Interactions between strains are of key importance for the performance of these fermentations. Yogurt fermentation by Streptococcus thermophilus and Lactobacillus bulgaricus (basonym, Lactobacillus delbrueckii subsp. bulgaricus) is one of the best-described mixed-culture fermentations. These species are believed to stimulate each other's growth by the exchange of metabolites such as folic acid and carbon dioxide. Recently, postgenomic studies revealed that an upregulation of biosynthesis pathways for nucleotides and sulfur-containing amino acids is part of the global physiological response to mixed-culture growth in S. thermophilus, but an in-depth molecular analysis of mixed-culture growth of both strains remains to be established. We report here the application of mixed-culture transcriptome profiling and a systematic analysis of the effect of interaction-related compounds on growth, which allowed us to unravel the molecular responses associated with batch mixed-culture growth in milk of S. thermophilus CNRZ1066 and L. bulgaricus ATCC BAA-365. The results indicate that interactions between these bacteria are primarily related to purine, amino acid, and long-chain fatty acid metabolism. The results support a model in which formic acid, folic acid, and fatty acids are provided by S. thermophilus. Proteolysis by L. bulgaricus supplies both strains with amino acids but is insufficient to meet the biosynthetic demands for sulfur and branched-chain amino acids, as becomes clear from the upregulation of genes associated with these amino acids in mixed culture. Moreover, genes involved in iron uptake in S. thermophilus are affected by mixed-culture growth, and genes coding for exopolysaccharide production were upregulated in both organisms in mixed culture compared to monocultures. The confirmation of previously identified responses in S. thermophilus using a different strain combination

  4. Organic carbon sequestration under selected land use in Padang city, West Sumatra, Indonesia

    Science.gov (United States)

    Yulnafatmawita; Yasin, S.

    2018-03-01

    Organic carbon is a potential element to build biomass as well as emitting CO2 to the atmosphere and promotes global warming. This research was aimed to calculate the sequestered Carbon (C) within a 1-m soil depth under selected land use from 6 different sites in Padang city, Indonesia. Disturbed and undisturbed soil samples were taken from several horizons until 100 cm depth at each location. Soil parameters observed were organic carbon (OC), bulk density (BD), and soil texture. The result showed that soil OC content tended to decrease by the depth at all land use types, except under rice field in Kurao-Nanggalo which extremely increased at >65 cm soil depth with the highest carbon stock. The soil organic carbon sequestration from the highest to the lowest according to land use and the location is in the following order mix garden- Kayu Aro > mix garden- Aie Pacah > Rangeland- Parak Laweh >seasonal farming- Teluk Sirih > rice field- Kampuang Jua.

  5. Determination of the origin of dissolved inorganic carbon in groundwater around a reclaimed landfill in Otwock using stable carbon isotopes.

    Science.gov (United States)

    Porowska, Dorota

    2015-05-01

    Chemical and isotopic analyses of groundwater from piezometers located around a reclaimed landfill in Otwock (Poland) were performed in order to trace the origin of dissolved inorganic carbon (DIC) in the groundwater. Due to differences in the isotopic composition of carbon from different sources, an analysis of stable carbon isotopes in the groundwater, together with the Keeling plot approach and a two-component mixing model allow us to evaluate the relative contributions of carbon from these sources in the groundwater. In the natural (background) groundwater, DIC concentrations and the isotopic composition of DIC (δ(13)CDIC) comes from two sources: decomposition of organic matter and carbonate dissolution within the aquifer sediments, whereas in the leachate-contaminated groundwater, DIC concentrations and δ(13)CDIC values depend on the degradation of organic matter within the aquifer sediments and biodegradation of organic matter stored in the landfill. From the mixing model, about 4-54% of the DIC pool is derived from organic matter degradation and 96-46% from carbonate dissolution in natural conditions. In the leachate-contaminated groundwater, about 20-53% of the DIC is derived from organic matter degradation of natural origin and 80-47% from biodegradation of organic matter stored in the landfill. Partial pressure of CO2 (P CO2) was generally above the atmospheric, hence atmospheric CO2 as a source of carbon in DIC pool was negligible in the aquifer. P CO2 values in the aquifer in Otwock were always one to two orders of magnitude above the atmospheric P CO2, and thus CO2 escaped directly into the vadose zone. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Assessing dissolved carbon transport and transformation along an estuarine river with stable isotope analyses

    Science.gov (United States)

    He, Songjie; Xu, Y. Jun

    2017-10-01

    Estuaries play an important role in the dynamics of dissolved carbon from rivers to coastal oceans. However, our knowledge of dissolved carbon transport and transformation in mixing zones of the world's coastal rivers is still limited. This study aims to determine how dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) concentrations and stable isotopes (δ13CDIC and δ13CDOC) change along an 88-km long estuarine river, the Calcasieu River in Louisiana, southern USA, with salinity ranging from 0.02 to 21.92. The study is expected to elucidate which processes most likely control carbon dynamics in a freshwater-saltwater mixing system, and to evaluate the net metabolism of this estuary. Between May 2015 and February 2016, water samples were collected and in-situ measurements on ambient water conditions were performed during five field trips at six sites from upstream to downstream of the Calcasieu River, which enters the Northern Gulf of Mexico (NGOM). The DIC concentration and δ13CDIC increased rapidly with increasing salinity in the mixing zone. The average DIC concentration and δ13CDIC at the site closest to the NGOM (site 6) were 1.31 mM and -6.34‰, respectively, much higher than those at the site furthest upstream (site 1, 0.42 mM and -20.83‰). The DIC concentrations appeared to be largely influenced by conservative mixing, while high water temperature may have played a role in deviating DIC concentration from the conservative line due likely to increased respiration and decomposition. The δ13CDIC values were close to those suggested by the conservative mixing model for May, June and November, but lower than those for July and February, suggesting that an estuarine river can fluctuate from a balanced to a heterotrophic system (i.e., production/respiration (P/R) aquatic photosynthesis from carbon produced by terrestrial photosynthesis in a river-ocean continuum.

  7. integrated vertical photobioreactor system for carbon dioxide

    African Journals Online (AJOL)

    Astri Nugroho

    2013-07-02

    Jul 2, 2013 ... efficient system for converting carbon dioxide (CO2) into biomass. The use of ... often been thought to achieve the most efficient mixing and the best ... such process a photobioreactor is designed. Photobioreactor is a device ...

  8. The carbon balance of reducing wildfire risk and restoring process: an analysis of 10-year post-treatment carbon dynamics in a mixed-conifer forest

    Science.gov (United States)

    Morgan L. Wiechmann; Matthew D. Hurteau; Malcolm P. North; George W. Koch; Lucie Jerabkova

    2015-01-01

    Forests sequester carbon from the atmosphere, helping mitigate climate change. In fire-prone forests, burn events result in direct and indirect emissions of carbon. High fire-induced tree mortality can cause a transition from a carbon sink to source, but thinning and prescribed burning can reduce fire severity and carbon loss when wildfire occurs. However, treatment...

  9. Toxicity of carbon nanotubes to the activated sludge process

    International Nuclear Information System (INIS)

    Luongo, Lauren A.; Zhang Xiaoqi

    2010-01-01

    The discharge of carbon nanotubes (CNTs) from industrial waste or disposal of such materials from commercial and/or domestic use will inevitably occur with increasing production and enter into wastewater treatment facilities with unknown consequences. Therefore, a better knowledge of the toxicity of CNTs to biological processes in wastewater treatment will be critical. This study examined the toxicity of multi-walled carbon nanotubes (MWCNTs) on the microbial communities in activated sludge. A comparative study using the activated sludge respiration inhibition test was performed on both unsheared mixed liquor and sheared mixed liquor to demonstrate the potential toxicity posed by MWCNTs and to illustrate the extent of extracellular polymeric substances (EPS) in protecting the microorganisms from the toxicity of CNTs. Respiration inhibition was observed for both unsheared and sheared mixed liquor when MWCNTs were present, however, greater respiration inhibition was observed for the sheared mixed liquor. The toxicity observed by the respiration inhibition test was determined to be dose-dependent; the highest concentration of MWCNTs exhibited the highest respiration inhibition. Scanning Electron Microscopy (SEM) images demonstrated direct physical contact between MWCNTs and activated sludge flocs.

  10. Raman Scattering in a New Carbon Material

    Science.gov (United States)

    Voronov, O. A.; Street, K. W., Jr.

    2010-01-01

    Samples of a new carbon material, Diamonite-B, were fabricated under high pressure from a commercial carbon black--identified as mixed fullerenes. The new material is neither graphite-like nor diamond-like, but exhibits electrical properties close to graphite and mechanical properties close to diamond. The use of Raman spectroscopy to investigate the vibrational dynamics of this new carbon material and to provide structural characterization of its short-, medium- and long-range order is reported. We also provide the results of investigations of these samples by high-resolution electron microscopy and X-ray diffraction. Hardness, electrical conductivity, thermal conductivity and other properties of this new material are compared with synthetic graphite-like and diamond-like materials, two other phases of synthetic bulk carbon.

  11. Accuracy Enhancement of Raman Spectroscopy Using Complementary Laser-Induced Breakdown Spectroscopy (LIBS) with Geologically Mixed Samples.

    Science.gov (United States)

    Choi, Soojin; Kim, Dongyoung; Yang, Junho; Yoh, Jack J

    2017-04-01

    Quantitative Raman analysis was carried out with geologically mixed samples that have various matrices. In order to compensate the matrix effect in Raman shift, laser-induced breakdown spectroscopy (LIBS) analysis was performed. Raman spectroscopy revealed the geological materials contained in the mixed samples. However, the analysis of a mixture containing different matrices was inaccurate due to the weak signal of the Raman shift, interference, and the strong matrix effect. On the other hand, the LIBS quantitative analysis of atomic carbon and calcium in mixed samples showed high accuracy. In the case of the calcite and gypsum mixture, the coefficient of determination of atomic carbon using LIBS was 0.99, while the signal using Raman was less than 0.9. Therefore, the geological composition of the mixed samples is first obtained using Raman and the LIBS-based quantitative analysis is then applied to the Raman outcome in order to construct highly accurate univariate calibration curves. The study also focuses on a method to overcome matrix effects through the two complementary spectroscopic techniques of Raman spectroscopy and LIBS.

  12. Spatial distributions of biogeochemical reactions in freshwater-saltwater mixing zones of sandy beach aquifers

    Science.gov (United States)

    Kim, K. H.; Michael, H. A.; Ullman, W. J.; Cai, W. J.

    2017-12-01

    Beach aquifers host biogeochemically dynamic mixing zones between fresh and saline groundwaters of contrasting origins, histories, and compositions. Seawater, driven up the beachface by waves and tides, infiltrates into the sand and meets the seaward-discharging fresh groundwater, creating and maintaining a highly reactive intertidal circulation cell well-defined by salinity. Seawater supplies oxygen and reactive carbon to the circulation cell, supporting biogeochemical reactions within the cell that transform and attenuate dissolved nutrient fluxes from terrestrial sources. We investigated the spatial distribution of chemical reaction zones within the intertidal circulation cell at Cape Shores, Lewes, Delaware. Porewater samples were collected from multi-level wells along a beach-perpendicular transect. Samples were analyzed for particulate carbon and reactive solutes, and incubated to obtain rates of oxic respiration and denitrification. High rates of oxic respiration were observed higher on the beach, in the landward freshwater-saline water mixing zone, where dissolved oxygen availability was high. Denitrification was dominant in lower areas of the beach, below the intertidal discharge point. High respiration rates did not correlate with particulate carbon concentrations entrained within porewater, suggesting that dissolved organic carbon or immobile particulate carbon trapped within the sediment can contribute to and alter bulk reactivity. A better understanding of the sources and sinks of carbon within the beach will improve our ability to predict nutrient fluxes to estuaries and oceans, aiding the management of coastal environments and ecosystems.

  13. Nano-QSAR: Genotoxicity of Multi-Walled Carbon Nanotubes

    International Nuclear Information System (INIS)

    Toropova, A. P.; Toropov, A. A.; Rallo, R.; Leszczynska, D.; Leszczynski, J.

    2016-01-01

    The study was carried out to develop an efficient approach for prediction the genotoxicity of carbon nano tubes. The experimental data on the bacterial reverse mutation test (TA100) on multi-walled carbon nano tubes was collected from the literature and examined as an endpoint. By means of the optimal descriptors calculated with the Monte Carlo method a mathematical model of the endpoint was built up. The model is represented by a function of: (i) dose (μg/plate); (ii) metabolic activation (i.e. with S9 mix or without S9 mix); and (iii) two types of multi-walled carbon nano tubes. The above listed conditions were represented by so-called quasi-SMILES. Simplified molecular input-line entry system (SMILES) is a tool for representation of molecular structure. The quasi-SMILES is a tool to represent physicochemical and / or biochemical conditions for building up a predictive model. Thus, instead of well-known paradigm of predictive modeling “endpoint is a mathematical function of molecular structure” a fresh paradigm “endpoint is a mathematical function of available eclectic data (conditions) is suggested.

  14. The Effect of the Interannual Variability of the OH Sink on the Interannual Variability of the Atmospheric Methane Mixing Ratio and Carbon Stable Isotope Composition

    Science.gov (United States)

    Guillermo Nuñez Ramirez, Tonatiuh; Houweling, Sander; Marshall, Julia; Williams, Jason; Brailsford, Gordon; Schneising, Oliver; Heimann, Martin

    2013-04-01

    The atmospheric hydroxyl radical concentration (OH) varies due to changes in the incoming UV radiation, in the abundance of atmospheric species involved in the production, recycling and destruction of OH molecules and due to climate variability. Variability in carbon monoxide emissions from biomass burning induced by El Niño Southern Oscillation are particularly important. Although the OH sink accounts for the oxidation of approximately 90% of atmospheric CH4, the effect of the variability in the distribution and strength of the OH sink on the interannual variability of atmospheric methane (CH4) mixing ratio and stable carbon isotope composition (δ13C-CH4) has often been ignored. To show this effect we simulated the atmospheric signals of CH4 in a three-dimensional atmospheric transport model (TM3). ERA Interim reanalysis data provided the atmospheric transport and temperature variability from 1990 to 2010. We performed simulations using time dependent OH concentration estimations from an atmospheric chemistry transport model and an atmospheric chemistry climate model. The models assumed a different set of reactions and algorithms which caused a very different strength and distribution of the OH concentration. Methane emissions were based on published bottom-up estimates including inventories, upscaled estimations and modeled fluxes. The simulations also included modeled concentrations of atomic chlorine (Cl) and excited oxygen atoms (O(1D)). The isotopic signal of the sources and the fractionation factors of the sinks were based on literature values, however the isotopic signal from wetlands and enteric fermentation processes followed a linear relationship with a map of C4 plant fraction. The same set of CH4emissions and stratospheric reactants was used in all simulations. Two simulations were done per OH field: one in which the CH4 sources were allowed to vary interannually, and a second where the sources were climatological. The simulated mixing ratios and

  15. Influences of organic carbon speciation on hyporheic corridor biogeochemistry and microbial ecology.

    Science.gov (United States)

    Stegen, James C; Johnson, Tim; Fredrickson, James K; Wilkins, Michael J; Konopka, Allan E; Nelson, William C; Arntzen, Evan V; Chrisler, William B; Chu, Rosalie K; Fansler, Sarah J; Graham, Emily B; Kennedy, David W; Resch, Charles T; Tfaily, Malak; Zachara, John

    2018-02-08

    The hyporheic corridor (HC) encompasses the river-groundwater continuum, where the mixing of groundwater (GW) with river water (RW) in the HC can stimulate biogeochemical activity. Here we propose a novel thermodynamic mechanism underlying this phenomenon and reveal broader impacts on dissolved organic carbon (DOC) and microbial ecology. We show that thermodynamically favorable DOC accumulates in GW despite lower DOC concentration, and that RW contains thermodynamically less-favorable DOC, but at higher concentrations. This indicates that GW DOC is protected from microbial oxidation by low total energy within the DOC pool, whereas RW DOC is protected by lower thermodynamic favorability of carbon species. We propose that GW-RW mixing overcomes these protections and stimulates respiration. Mixing models coupled with geophysical and molecular analyses further reveal tipping points in spatiotemporal dynamics of DOC and indicate important hydrology-biochemistry-microbial feedbacks. Previously unrecognized thermodynamic mechanisms regulated by GW-RW mixing may therefore strongly influence biogeochemical and microbial dynamics in riverine ecosystems.

  16. Improvement in char formability of phenolic resin for development of Carbon/Carbon composites

    International Nuclear Information System (INIS)

    Hajhosseini, M.; Payami, A.; Ghaffarian, S. R.; Rezadoust, A. M.

    2008-01-01

    In the processing of carbon/carbon composites using polymer resin as the matrix precursor, it is inevitable that a porous structure was formed after carbonization. As a result, densification by liquid phase impregnation followed by recarbonization is required to obtain a densified composite. Consequently, the char formability of resin is an important factor in reducing the number of densification cycles and hence the processing cost. In this study, a novel approach is adopted to improve the densification of carbon/carbon composites by using a new phenolic resin modified by pitch. For this purpose, soluble part of pitch was extracted and dispersed in resol type phenolic resin. The polymerization reaction was performed in presence of para-formaldehyde and a resol-pitch compound was obtained. The second compound was prepared by mixing novolac-furfural in 55:45 weight ratio containing 9% by weight hexamethylene tetramine. This compound was added to resol-pitch compound in 10,20,50 and 80 w %. The microstructure of carbonized resin was investigated by X-ray diffraction and char yield, and the linear and volumetric shrinkage were obtained. Results show that in 80:20 ratio of resol-pitch to novolac-furfural , the char yield would be maximized by 71% and volumetric shrinkage would be minimized at 16.4%. At the same time, XRD results indicate that the resin has a strong ability to graphitize carbon/carbon composites matrix as a necessary step for its processing

  17. Wolframite Conversion in Treating a Mixed Wolframite-Scheelite Concentrate by Sulfuric Acid

    Science.gov (United States)

    Shen, Leiting; Li, Xiaobin; Zhou, Qiusheng; Peng, Zhihong; Liu, Guihua; Qi, Tiangui; Taskinen, Pekka

    2018-02-01

    Complete wolframite conversion in sulfuric acid is significant for expanding the applicability of the sulfuric acid method for producing ammonium paratungstate. In this paper, the conversion of wolframite in treating a mixed wolframite-scheelite concentrate by sulfuric acid was studied systematically. The results show that the conversion of wolframite in sulfuric acid is more difficult than that of scheelite, requiring rigorous reaction conditions. A solid H2WO4 layer forms on the surfaces of the wolframite particles and becomes denser with increasing H2SO4 concentration, thus hindering the conversion. Furthermore, the difficulty in wolframite conversion can be mainly attributed to the accumulation of Fe2+ (and/or Mn2+) in the H2SO4 solution, which can be solved by reducing Fe2+ (and/or Mn2+) concentration through oxidization and/or a two-stage process. Additionally, the solid converted product of the mixed wolframite-scheelite concentrate has an excellent leachability of tungsten in an aqueous ammonium carbonate solution at ambient temperature, with approximately 99% WO3 recovery. This work presents a route for manufacturing ammonium paratungstate by treating the mixed concentrate in sulfuric acid followed by leaching in ammonium carbonate solution.

  18. Spatiotemporal variation of radon and carbon dioxide concentrations in an underground quarry: coupled processes of natural ventilation, barometric pumping and internal mixing

    International Nuclear Information System (INIS)

    Perrier, Frederic; Richon, Patrick

    2010-01-01

    Radon-222 and carbon dioxide concentrations have been measured during several years at several points in the atmosphere of an underground limestone quarry located at a depth of 18 m in Vincennes, near Paris, France. Both concentrations showed a seasonal cycle. Radon concentration varied from 1200 to 2000 Bq m -3 in summer to about 800-1400 Bq m -3 in winter, indicating winter ventilation rates varying from 0.6 to 2.5 x 10 -6 s -1 . Carbon dioxide concentration varied from 0.9 to 1.0% in summer, to about 0.1-0.3% in winter. Radon concentration can be corrected for natural ventilation using temperature measurements. The obtained model also accounts for the measured seasonal variation of carbon dioxide. After correction, radon concentrations still exhibit significant temporal variation, mostly associated with the variation of atmospheric pressure, with coupling coefficients varying from -7 to -26 Bq m -3 hPa -1 . This variation can be accounted for using a barometric pumping model, coupled with natural ventilation in winter, and including internal mixing as well. After correction, radon concentrations exhibit residual temporal variation, poorly correlated between different points, with standard deviations varying from 3 to 6%. This study shows that temporal variation of radon concentrations in underground cavities can be understood to a satisfactory level of detail using non-linear and time-dependent modelling. It is important to understand the temporal variation of radon concentrations and the limitations in their modelling to monitor the properties of natural or artificial underground settings, and to be able to assess the existence of new processes, for example associated with the preparatory phases of volcanic eruptions or earthquakes.

  19. Urban tree effects on soil organic carbon.

    Directory of Open Access Journals (Sweden)

    Jill L Edmondson

    Full Text Available Urban trees sequester carbon into biomass and provide many ecosystem service benefits aboveground leading to worldwide tree planting schemes. Since soils hold ∼75% of ecosystem organic carbon, understanding the effect of urban trees on soil organic carbon (SOC and soil properties that underpin belowground ecosystem services is vital. We use an observational study to investigate effects of three important tree genera and mixed-species woodlands on soil properties (to 1 m depth compared to adjacent urban grasslands. Aboveground biomass and belowground ecosystem service provision by urban trees are found not to be directly coupled. Indeed, SOC enhancement relative to urban grasslands is genus-specific being highest under Fraxinus excelsior and Acer spp., but similar to grasslands under Quercus robur and mixed woodland. Tree cover type does not influence soil bulk density or C∶N ratio, properties which indicate the ability of soils to provide regulating ecosystem services such as nutrient cycling and flood mitigation. The trends observed in this study suggest that genus selection is important to maximise long-term SOC storage under urban trees, but emerging threats from genus-specific pathogens must also be considered.

  20. Ocean uptake of carbon dioxide

    International Nuclear Information System (INIS)

    Peng, Tsung-Hung; Takahashi, Taro

    1993-01-01

    Factors controlling the capacity of the ocean for taking up anthropogenic C0 2 include carbon chemistry, distribution of alkalinity, pCO 2 and total concentration of dissolved C0 2 , sea-air pCO 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 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 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 2 fertilization is a potential candidate for such missing carbon sinks

  1. Quantum-CEP trademark for mixed waste processing

    International Nuclear Information System (INIS)

    Nahass, P.; Sekula-Moise, P.A.; Chanenchuk, C.A.

    1994-01-01

    No commercially available technology exists to effectively treat the hundreds of thousands of tons of mixed waste stored and generated in the United States and worldwide. Catalytic Extraction Processing (CEP) is an innovative flexible recycling technology which has inherent advantages for processing mixed wastes in a wide variety of chemical and physical forms. CEP uses a molten metal bath to completely dissociate feeds and recombine them with selected reactants to form useful products. Dissolved carbon in the metal bath creates a reducing atmosphere, readily converting hydrocarbons to synthesis gas, metals to alloys in their reduced state, and inorganics to an engineered ceramic phase. Process conditions can be manipulated to strongly favor partitioning of select radionuclides to a nonleachable vitreous phase, ready for final form disposal. Molten Metal Technology has adapted its CEP technology for radioactive processing and has delivered Quantum-CEP trademark units to customers for demonstration of mixed waste processing leading to commercial scale installations for reducing both private and government inventories. Agreements have also been reached to build commercial CEP facilities to recycle hazardous and industrial wastes

  2. Synthesis of glycerol carbonate by transesterification of glycerol with dimethyl carbonate over MgAl mixed oxide catalysts

    NARCIS (Netherlands)

    Liu, P.; Derchi, M.; Hensen, E.J.M.

    2013-01-01

    A series of hydrotalcite-like layered double hydroxides (LDHx) with different Mg/Al atomic ratios (x = 2–6) were prepared by using the co-precipitation method. Further calcination yields mixed oxides with tunable basicity. The basicity of the calcined LDHx (LDOx) strongly depends on the Mg/Al ratio

  3. Carbon Composition of Particulate Organic Carbon in the Gulf of Mexico

    Science.gov (United States)

    Rogers, K.; Montoya, J. P.; Weber, S.; Bosman, S.; Chanton, J.

    2016-02-01

    The Deepwater Horizon blowout released 5.0x1011 g C from gaseous hydrocarbons and up to 6.0x1011g C from oil into the water column. Another carbon source, adding daily to the water column, leaks from the natural hydrocarbon seeps that pepper the seafloor of the Gulf of Mexico. How much of this carbon from the DWH and natural seeps is assimilated into particulate organic carbon (POC) in the water column? We filtered seawater collected in 2010, 2012, and 2013 from seep and non-seep sites, collecting POC on 0.7µm glass microfiber filters and analyzing the POC for stable and radiocarbon isotopes. Mixing models based on carbon isotopic endmembers of methane, oil, and modern production were used to estimate the percentage of hydrocarbon incorporated into POC. Significant differences were seen between POC from shallow and deep waters and between POC collected from seep, non-seep, and blowout sites; however yearly differences were not as evident suggesting the GOM has a consistent supply of depleted carbon. Stable carbon isotopes signatures of POC in the Gulf averaged -23.7±2.5‰ for shallow samples and -26.65±2.9‰ for deep POC samples, while radiocarbon signatures averaged -100.4±146.1‰ for shallow and -394.6±197‰ for deep samples. POC in the northern Gulf are composed of 23-91% modern carbon, 2-21% methane, and 0-71% oil. Oil plays a major role in the POC composition of the GOM, especially at the natural seep GC600.

  4. Carbon dioxide problem: solution by technical countermeasures

    Energy Technology Data Exchange (ETDEWEB)

    Bach, W

    1978-02-15

    A rough assessment indicates that anthropogenic influences might raise the mean global surface temperature by 0.8 to 1.2 C in 2000 AD and by 2 to 4 C in 2050 AD. The rapidly increasing levels of atmospheric carbon dioxide are largely responsible for this warming trend. A variety of measures for the reduction of carbon dioxide emissions is presented. One promising approach is to work out a world-wide energy mix that can counteract a temperature increase. (In German)

  5. The diversification value of nuclear power as part of a utility technology mix when gas and carbon prices are uncertain

    International Nuclear Information System (INIS)

    Roques, Fabien A.; Nuttall, William J.; Newbery, David M.; Neufville, Richard de; Connors, Stephen

    2005-01-01

    Despite recent revived interest, the prospects for new nuclear power investment in liberalized electricity industries without government support do not seem promising. The objective of this paper is twofold. First it aims to identify the specific features of nuclear power technology that makes it an unattractive choice. The second objective is to estimate the value to a utility of a nuclear investment as a hedge against uncertain gas and carbon prices. A stylized 5-plant Real Option utility model shows that while the nuclear option value represents about 18% of the net present value (NPV) of the nuclear plant investment in the case where electricity and gas prices are uncorrelated, it reduces to nearly zero for correlation factors between electricity and gas price greater than 30%. These results suggest that the private diversification incentives in electricity markets might not be aligned with the social value of a diverse fuel-mix at the country level. (Author)

  6. Climate, carbon cycling, and deep-ocean ecosystems.

    Science.gov (United States)

    Smith, K L; Ruhl, H A; Bett, B J; Billett, D S M; Lampitt, R S; Kaufmann, R S

    2009-11-17

    Climate variation affects surface ocean processes and the production of organic carbon, which ultimately comprises the primary food supply to the deep-sea ecosystems that occupy approximately 60% of the Earth's surface. Warming trends in atmospheric and upper ocean temperatures, attributed to anthropogenic influence, have occurred over the past four decades. Changes in upper ocean temperature influence stratification and can affect the availability of nutrients for phytoplankton production. Global warming has been predicted to intensify stratification and reduce vertical mixing. Research also suggests that such reduced mixing will enhance variability in primary production and carbon export flux to the deep sea. The dependence of deep-sea communities on surface water production has raised important questions about how climate change will affect carbon cycling and deep-ocean ecosystem function. Recently, unprecedented time-series studies conducted over the past two decades in the North Pacific and the North Atlantic at >4,000-m depth have revealed unexpectedly large changes in deep-ocean ecosystems significantly correlated to climate-driven changes in the surface ocean that can impact the global carbon cycle. Climate-driven variation affects oceanic communities from surface waters to the much-overlooked deep sea and will have impacts on the global carbon cycle. Data from these two widely separated areas of the deep ocean provide compelling evidence that changes in climate can readily influence deep-sea processes. However, the limited geographic coverage of these existing time-series studies stresses the importance of developing a more global effort to monitor deep-sea ecosystems under modern conditions of rapidly changing climate.

  7. Developing an optimal electricity generation mix for the UK 2050 future

    International Nuclear Information System (INIS)

    Sithole, H.; Cockerill, T.T.; Hughes, K.J.; Ingham, D.B.; Ma, L.; Porter, R.T.J.; Pourkashanian, M.

    2016-01-01

    The UK electricity sector is undergoing a transition driven by domestic and regional climate change and environmental policies. Aging electricity generating infrastructure is set to affect capacity margins after 2015. These developments, coupled with the increased proportion of inflexible and variable generation technologies will impact on the security of electricity supply. Investment in low-carbon technologies is central to the UK meeting its energy policy objectives. The complexity of these challenges over the future development of the UK electricity generation sector has motivated this study which aims to develop a policy-informed optimal electricity generation scenario to assess the sector's transition to 2050. The study analyses the level of deployment of electricity generating technologies in line with the 80% by 2050 emission target. This is achieved by using an excel-based “Energy Optimisation Calculator” which captures the interaction of various inputs to produce a least-cost generation mix. The key results focus on the least-cost electricity generation portfolio, emission intensity, and total investment required to assemble a sustainable electricity generation mix. A carbon neutral electricity sector is feasible if low-carbon technologies are deployed on a large scale. This requires a robust policy framework that supports the development and deployment of mature and emerging technologies. - Highlights: • Electricity generation decarbonised in 2030 and nearly carbon neutral in 2050. • Nuclear, CCS and offshore wind are central in decarbonising electricity generation. • Uncertainty over future fuel and investment cost has no impact on decarbonisation. • Unabated fossil fuel generation is limited unless with Carbon Capture and Storage. • Decarbonising the electricity generation could cost about £213.4 billion by 2030.

  8. Process for carbonizing hard-to-heat bituminous material like shale

    Energy Technology Data Exchange (ETDEWEB)

    Nagel, K

    1921-11-29

    A process is described for carbonizing bituminous material, like shale, with the production of sufficient heat for carbonization by burning a part of the bitumen itself by means of a gas stream going in a circuit, to which oxygen in regulated amounts is admitted. It is characterized by the fact that the gas stream already cooled for detarring before its re-entrance into the carbonization chamber is mixed in the inlet channels with an amount of oxygen (air or other free oxygen containing gases), that without sintering or melting of the residue it is burned and the carbonization is carried out evenly.

  9. Effects of mixed substrates on growth and vitamin production by ...

    African Journals Online (AJOL)

    The effects of mixed carbon sources on growth and production of vitamins E and A by Euglena gracilis cells were investigated in batch culture. The cells were grown mixotrophically in glucose (G), ethanol (E) and a mixture of glucose and ethanol (EG). Cell growth was measured by counting the cell number with microscope, ...

  10. Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems

    International Nuclear Information System (INIS)

    Soelberg, Nick; Enneking, Joe

    2011-01-01

    Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absorption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring of bed outlet gas CO concentrations. Hot spots are mitigated by (a) designing for appropriate in-bed gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) appropriate monitoring and control of gas and bed temperatures and compositions, and (c) prompt implementation of corrective actions if bed hot spots are detected. Corrective actions must be implemented quickly if bed hot spots are detected, using a graded approach and sequence starting with corrective actions that are simple, quick, cause the least impact to the process, and are easiest to recover from.

  11. Mixed field dosimetry with the twin chamber technique

    International Nuclear Information System (INIS)

    Burger, G.; Maier, E.

    1974-04-01

    For the separate dosimetry of the neutron- and gamma-component in a mixed beam it is principally possible to use two ionization chambers with different ratios of neutron- to gamma sensitivity. Several authors proposed for this purpose the use of a homogenious TE-chamber filled with the TE-gas and of a carbon-chamber filled with CO 2 -gas. This chamber combination is also commercially available in several countries. The chambers are normally equipped with a continuous gas-flow provision and with a waterproof-housing for the use within liquid phantoms. The application of such chambers for mixed field dosimetry in the intercomparison project of the ICRU at the RARAF-facility in Brookhaven (International Neutron Dosimetry Intercomparison - INDI) is described. (orig./HP) [de

  12. Influence of activated carbon amendment on the accumulation and elimination of PCBs in the earthworm Eisenia fetida

    Energy Technology Data Exchange (ETDEWEB)

    Paul, Piuly [Department of Civil and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MA 21250 (United States); Ghosh, Upal, E-mail: ughosh@umbc.edu [Department of Civil and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MA 21250 (United States)

    2011-12-15

    In this study we investigated the use of activated carbon (AC) as a soil amendment for reducing bioavailability of polychlorinated biphenyls (PCBs) to the earthworm Eisenia fetida. Artificial soil was contaminated with PCBs and used in bioaccumulation experiments fresh or after aging for 19 months. PCB bioaccumulation in earthworms was reduced by 68% when AC was placed as a layer without mixing and by 94% when AC was manually mixed into the soil. Aging of the same AC mixed soil for 19 months resulted in an overall reduction of 99% in PCB biouptake. AC-treated aged soil also showed two orders of magnitude lower equilibrium aqueous concentrations of PCBs compared to untreated aged soils. The findings from this study indicate that application of engineered sorbents like AC to PCB impacted soils may greatly reduce PCB uptake at the base of the terrestrial food chain. - Graphical abstract: Display Omitted Highlights: > Activated carbon studied as a sorbent for PCB impacted unsaturated soil. > Bioaccumulation of PCB greatly reduced in earthworms after carbon amendment. > Aging of the activated carbon amended soil further reduced bioaccumulation. > Activated carbon can be used for in-situ stabilization of PCB impacted soil. - Addition of activated carbon to PCB impacted soil reduces equilibrium aqueous concentrations and uptake at the base of the terrestrial food chain.

  13. Assessing the value of wind generation in future carbon constrained electricity industries

    International Nuclear Information System (INIS)

    Vithayasrichareon, Peerapat; MacGill, Iain F.

    2013-01-01

    This paper employs a novel Monte-Carlo based generation portfolio assessment tool to explore the implications of increasing wind penetration and carbon prices within future electricity generation portfolios under considerable uncertainty. This tool combines optimal generation mix techniques with Monte Carlo simulation and portfolio analysis methods to determine expected overall generation costs, associated cost uncertainty and expected CO 2 emissions for different possible generation portfolios. A case study of an electricity industry with coal, Combined Cycle Gas Turbines (CCGT), Open Cycle Gas Turbines (OCGT) and wind generation options that faces uncertain future fossil-fuel prices, carbon pricing, electricity demand and plant construction costs is presented to illustrate some of the key issues associated with growing wind penetrations. The case study uses half-hourly demand and wind generation data from South Eastern Australia, and regional estimates of new-build plant costs and characteristics. Results suggest that although wind generation generally increases overall industry costs, it reduces associated cost uncertainties and CO 2 emissions. However, there are some cases in which wind generation can reduce the overall costs of generation portfolios. The extent to which wind penetration affects industry expected costs and uncertainties depends on the level of carbon price and the conventional technology mix in the portfolios. - Highlights: ► A probabilistic portfolio analysis tool to assess generation portfolios with wind power. ► Explore the impacts of wind penetrations and carbon prices under uncertainties. ► Wind generation increases overall portfolio costs but reduces cost risks and emissions. ► The value of wind power depends on the carbon price and the technology mix. ► Complex interactions between wind penetration level and carbon pricing.

  14. The effect of the chain length distribution of free fatty acids on the mixing properties of stratum corneum model membranes.

    Science.gov (United States)

    Oguri, Masashi; Gooris, Gert S; Bito, Kotatsu; Bouwstra, Joke A

    2014-07-01

    The stratum corneum (SC) plays a fundamental role in the barrier function of the skin. The SC consists of corneocytes embedded in a lipid matrix. The main lipid classes in the lipid matrix are ceramides (CERs), cholesterol (CHOL) and free fatty acids (FFAs). The aim of this study was to examine the effect of the chain length of FFAs on the thermotropic phase behavior and mixing properties of SC lipids. Fourier transform infrared spectroscopy and Raman imaging spectroscopy were used to study the mixing properties using either protonated or deuterated FFAs. We selected SC model lipid mixtures containing only a single CER, CHOL and either a single FFA or a mixture of FFAs mimicking the FFA SC composition. The single CER consists of a sphingoid base with 18 carbon atoms and an acyl chain with a chain length of 24 carbon atoms. When using lignoceric acid (24 carbon atoms) or a mixture of FFAs, the CER and FFAs participated in mixed crystals, but hydration of the mixtures induced a slight phase separation between CER and FFA. The mixed crystalline structures did not phase separate during storage even up to a time period of 3months. When using palmitic acid (16 carbon atoms), a slight phase separation was observed between FFA and CER. This phase separation was clearly enhanced during hydration and storage. In conclusion, the thermotropic phase behavior and the mixing properties of the SC lipid mixtures were shown to strongly depend on the chain length and chain length distribution of FFAs, while hydration enhanced the phase separation. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Impact of carbon constraint on the European electricity sector

    International Nuclear Information System (INIS)

    Stankeviciute, Loreta

    2010-01-01

    Two sets of factors will be decisive for the future evolution of European electricity sector: on the one hand, the necessity of new wave of investments for the renewal and the expansion of production capacities and, on the other hand, the emergency and the reinforcement of greenhouse gas emissions (GHG) constraints imposed by European policies and directives. The general idea of thesis is that European Emissions Trading system (ETS) is the instrument that can facilitate the decarbonization of European electricity system. However, the necessary conditions ought to be brought together in the context of liberalisation in terms of risk management, market architecture and setting up of the complementary public policy instruments, in order for the carbon price signal to be effective. The purpose of the thesis is to provide details on these conditions and to examine the potentials scenarios for the evolution of European electricity production mix under the carbon constraint. The introduction of liberalisation in the electricity industry conditions significantly the investment choice. The analysis of theoretical market model allows demonstrating organisational inadequacy for developing an optimal technological mix and for adapting to long-term issues due to the extreme difficulty of interpreting the price signals. Indeed, the logic of a market and a concurrence disadvantages the investments in capital-intensive technologies, even though some of them less polluting like renewable energies, nuclear, hydraulic and thermal technologies integrating carbon capture and sequestration (CCS). In face of numerous uncertainties, the role of long-term risk management becomes therefore crucial. The employment of transaction cost theory allows studying the combinations of vertical arrangements that remain necessary in order to manage the risk and to facilitate the investments (e.g. vertical integration). The introduction of ETS overlaps with the market risks inherent to liberalisation

  16. Land-use change and carbon sinks: Econometric estimation of the carbon sequestration supply function

    Energy Technology Data Exchange (ETDEWEB)

    Lubowski, Ruben N.; Plantinga, Andrew J.; Stavins, Robert N.

    2001-01-01

    Increased attention by policy makers to the threat of global climate change has brought with it considerable interest in the possibility of encouraging the expansion of forest area as a means of sequestering carbon dioxide. The marginal costs of carbon sequestration or, equivalently, the carbon sequestration supply function will determine the ultimate effects and desirability of policies aimed at enhancing carbon uptake. In particular, marginal sequestration costs are the critical statistic for identifying a cost-effective policy mix to mitigate net carbon dioxide emissions. We develop a framework for conducting an econometric analysis of land use for the forty-eight contiguous United States and employing it to estimate the carbon sequestration supply function. By estimating the opportunity costs of land on the basis of econometric evidence of landowners' actual behavior, we aim to circumvent many of the shortcomings of previous sequestration cost assessments. By conducting the first nationwide econometric estimation of sequestration costs, endogenizing prices for land-based commodities, and estimating land-use transition probabilities in a framework that explicitly considers the range of land-use alternatives, we hope to provide better estimates eventually of the true costs of large-scale carbon sequestration efforts. In this way, we seek to add to understanding of the costs and potential of this strategy for addressing the threat of global climate change.

  17. Carbon dioxide selective mixed matrix composite membrane containing ZIF-7 nano-fillers

    KAUST Repository

    Li, Tao; Pan, Yichang; Peinemann, Klaus-Viktor; Lai, Zhiping

    2013-01-01

    Mixed matrix materials made from selective inorganic fillers and polymers are very attractive for the manufacturing of gas separation membranes. But only few of these materials could be manufactured into high-performance asymmetric or composite

  18. Deposition of titanium carbide films from mixed carbon and titanium plasma streams

    International Nuclear Information System (INIS)

    Delplancke-Ogletree, M.; Monteiro, O.R.

    1997-01-01

    Dual source metal plasma immersion ion implantation and deposition was used to deposit Ti x C y films over a wide range of Ti:C composition. This technique is well adapted for this purpose and allows one to tailor the microstructure and properties of the films. We investigated the variation of the composition, bonding states, and structure as functions of the deposition conditions. Excess carbon and contamination oxygen are incorporated in the TiC lattice interstitially and substitutionally, respectively. The wear mechanism of a stoichiometric TiC film was investigated and compared to that of a diamondlike carbon film. TiC fails by wear and microcrack propagation. copyright 1997 American Vacuum Society

  19. Estimating Carbon Dynamics in an Intact Lowland Mixed Dipterocarp Forest Using a Forest Carbon Model

    Directory of Open Access Journals (Sweden)

    Jongyeol Lee

    2017-04-01

    Full Text Available Intact dipterocarp forests in Asia act as crucial carbon (C reservoirs, and it is therefore important to investigate the C dynamics in these forests. We estimated C dynamics, together with net ecosystem production (NEP, in an intact tropical dipterocarp forest of Brunei Darussalam. Fifty-four simulation units (plots; 20 m × 20 m were established and initial C stocks were determined via direct field measurement. The C dynamics were annually simulated with a regression model and the Forest Biomass and Dead organic matter Carbon (FBDC model. The initial C stock (Mg C·ha−1 of biomass, litter, dead wood and mineral soil were 213.1 ± 104.8, 2.0 ± 0.8, 31.3 ± 38.8, and 80.7 ± 15.5, respectively. Their annual changes (Mg C·ha−1·year−1 were 3.2 ± 1.1, 0.2 ± 0.2, −3.7 ± 6.1, and −0.3 ± 1.1, respectively. NEP was −0.6 ± 6.1 Mg C·ha−1·year−1, showing large heterogeneity among the plots. The initial C stocks of biomass and dead wood, biomass turnover rates and dead wood decay rates were elucidated as dominant factors determining NEP in a sensitivity analysis. Accordingly, investigation on those input data can constrain an uncertainty in determining NEP in the intact tropical forests.

  20. Carbon nanotube- and carbon fiber-reinforcement of ethylene-octene copolymer membranes for gas and vapor separation.

    Science.gov (United States)

    Sedláková, Zuzana; Clarizia, Gabriele; Bernardo, Paola; Jansen, Johannes Carolus; Slobodian, Petr; Svoboda, Petr; Kárászová, Magda; Friess, Karel; Izak, Pavel

    2014-01-03

    Gas and vapor transport properties were studied in mixed matrix membranes containing elastomeric ethylene-octene copolymer (EOC or poly(ethylene-co-octene)) with three types of carbon fillers: virgin or oxidized multi-walled carbon nanotubes (CNTs) and carbon fibers (CFs). Helium, hydrogen, nitrogen, oxygen, methane, and carbon dioxide were used for gas permeation rate measurements. Vapor transport properties were studied for the aliphatic hydrocarbon (hexane), aromatic compound (toluene), alcohol (ethanol), as well as water for the representative samples. The mechanical properties and homogeneity of samples was checked by stress-strain tests. The addition of virgin CNTs and CFs improve mechanical properties. Gas permeability of EOC lies between that of the more permeable PDMS and the less permeable semi-crystalline polyethylene and polypropylene. Organic vapors are more permeable than permanent gases in the composite membranes, with toluene and hexane permeabilities being about two orders of magnitude higher than permanent gas permeability. The results of the carbon-filled membranes offer perspectives for application in gas/vapor separation with improved mechanical resistance.

  1. Carbon Nanotube- and Carbon Fiber-Reinforcement of Ethylene-Octene Copolymer Membranes for Gas and Vapor Separation

    Directory of Open Access Journals (Sweden)

    Zuzana Sedláková

    2014-01-01

    Full Text Available Gas and vapor transport properties were studied in mixed matrix membranes containing elastomeric ethylene-octene copolymer (EOC or poly(ethylene-co-octene with three types of carbon fillers: virgin or oxidized multi-walled carbon nanotubes (CNTs and carbon fibers (CFs. Helium, hydrogen, nitrogen, oxygen, methane, and carbon dioxide were used for gas permeation rate measurements. Vapor transport properties were studied for the aliphatic hydrocarbon (hexane, aromatic compound (toluene, alcohol (ethanol, as well as water for the representative samples. The mechanical properties and homogeneity of samples was checked by stress-strain tests. The addition of virgin CNTs and CFs improve mechanical properties. Gas permeability of EOC lies between that of the more permeable PDMS and the less permeable semi-crystalline polyethylene and polypropylene. Organic vapors are more permeable than permanent gases in the composite membranes, with toluene and hexane permeabilities being about two orders of magnitude higher than permanent gas permeability. The results of the carbon-filled membranes offer perspectives for application in gas/vapor separation with improved mechanical resistance.

  2. Development of carbon-ceramic composites

    International Nuclear Information System (INIS)

    Raman, V.; Bhatia, G.; Mishra, A.; Sengupta, P.R.; Saha, M.; Rashmi

    2005-01-01

    Carbon-ceramic composites (C-SiC-B 4 C) were developed through in situ formation of silicon carbide by mixing coal-tar based green coke and silicon as silicon carbide (SiC) precursor, boron carbide (B 4 C) and heat-treatment to 2200 deg. C. These composites were characterised for their physical, mechanical and oxidation resistance properties. The formation of protective coatings during oxidation of the composites was confirmed by using X-ray diffraction, energy-dispersive X-ray spectrometry, scanning electron microscopy and porosity measurement. Carbon-ceramic composites, which could withstand oxidation at 800-1200 deg. C for about 10 h in air have been developed

  3. Carbon Storage and Allocation Pattern in Plant Biomass among Different Forest Plantation Stands in Guangdong, China

    Directory of Open Access Journals (Sweden)

    Yuanqi Chen

    2015-03-01

    Full Text Available In order to understand how carbon storage and allocation patterns vary among plantation types, we estimated carbon allocation between above- and below-ground compartments in four subtropical plantations and a naturally recovered shrubland (as a control. Results indicated that the carbon storage and allocation pattern varied greatly among forest types and was highly dependent on specific traits of trees and understory vegetation. The fast-growing species, such as Eucalyptus urophylla, accumulated more carbon in plant biomass. The biomass carbon was about 1.9- and 2.2-times greater than the 10-species mixed plantation and Castanopsis hystrix plantations, respectively. Meanwhile, the plantations sequestered 1.5- to 3-times more carbon in biomass than naturally recovered shrubland. The carbon allocation pattern between above- and below-ground compartments also varied with plantation type and stand age. The ratio of tree root carbon to tree aboveground carbon decreased with stand age for Eucalyptus urophylla and the 10-species mixed plantation. In contrast, the ratio increased for Acacia crassicarpa. Our data suggested that planting the fast-growing species in the degraded land of subtropical China was an effective choice in terms of carbon sequestration. The information about carbon allocation patterns was also valuable for decision making in sustainable forest management and climate change mitigation.

  4. Pyrogenic carbon emission from a large wildfire in Oregon, United States.

    Science.gov (United States)

    J. Campbell; D. Donato; D. Azuma; B. Law

    2007-01-01

    We used a ground-based approach to compute the pyrogenic carbon emissions from the Biscuit Fire, an exceptionally large wildfire, which in 2002 burned over 200,000 ha of mixed conifer forest in southwestern Oregon. A combination of federal inventory data and supplementary ground measurements afforded the estimation of preburn densities for 25 separate carbon pools at...

  5. Assessment of the importance of mixing in the Yucca Mountain hydrogeological system

    International Nuclear Information System (INIS)

    Gomez, Javier B.; Auque, Luis F.; Gimeno, Maria; Acero, Patricia; Peterman, Zell; Oliver, Thomas A.; Gascoyne, Mel; Laaksoharju, Marcus

    2011-02-01

    The main objective of this work is to assess the importance of mixing on the hydrochemistry of waters in and around Yucca Mountain, most importantly in those waters south of Yucca Mountain. Due to the general north-south gradient of groundwater flow in the Yucca Mountain area, leakage from the proposed high-level radioactive waste repository would have the greatest consequences in the saturated zone waters south of Yucca Mountain. In this area (Amargosa River, Amargosa Flat and Ash Meadows), three main aquifers interact: the Regional Palaeozoic Carbonate Aquifer (RCA), the Tertiary Tuffs Aquifer (TTA) and the Quaternary Basin-fill Aquifer (QBfA). One consequence of upward leakage from the Palaeozoic Carbonate Aquifer would be to dilute the contaminant plume should one develop from the radioactive waste repository at Yucca Mountain. The reverse, downward leakage from the Tertiary Tuffs Aquifer or the Quaternary Basin-fill Aquifer into the Palaeozoic Carbonate Aquifer would contaminate a major aquifer system. It is clearly of the utmost importance to explore the links between theses aquifer systems and to assess the degree of mixing between the groundwaters. To attain this general objective, the following specific objectives have been either defined in advance or decided as being important during the development of the project: 1. Compile a dataset of water samples from the Yucca Mountain area. This dataset should contain samples from all the potential water types that contribute to the chemistry of the groundwaters in the aquifer systems in the area. 2. Perform a careful total-system exploratory analysis on the initial (raw) dataset in order to identify trends and outliers. 3. Perform a detailed exploratory analysis of each individual hydrofacies with the aim of identifying and eliminating from the raw dataset all the samples heavily affected by processes other than mixing (e.g. water-rock interaction, evaporation, cation exchange). PHREEQC simulations were

  6. Assessment of the importance of mixing in the Yucca Mountain hydrogeological system

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Javier B.; Auque, Luis F.; Gimeno, Maria; Acero, Patricia (Geochemical Modelling Group, Dept. of Earth Sciences, Univ. of Zaragoza (Spain)); Peterman, Zell; Oliver, Thomas A. (U.S. Geological Survey (United States)); Gascoyne, Mel (Gascoyne Geoprojects Inc (Canada)); Laaksoharju, Marcus (Geopoint AB (Sweden))

    2011-02-15

    The main objective of this work is to assess the importance of mixing on the hydrochemistry of waters in and around Yucca Mountain, most importantly in those waters south of Yucca Mountain. Due to the general north-south gradient of groundwater flow in the Yucca Mountain area, leakage from the proposed high-level radioactive waste repository would have the greatest consequences in the saturated zone waters south of Yucca Mountain. In this area (Amargosa River, Amargosa Flat and Ash Meadows), three main aquifers interact: the Regional Palaeozoic Carbonate Aquifer (RCA), the Tertiary Tuffs Aquifer (TTA) and the Quaternary Basin-fill Aquifer (QBfA). One consequence of upward leakage from the Palaeozoic Carbonate Aquifer would be to dilute the contaminant plume should one develop from the radioactive waste repository at Yucca Mountain. The reverse, downward leakage from the Tertiary Tuffs Aquifer or the Quaternary Basin-fill Aquifer into the Palaeozoic Carbonate Aquifer would contaminate a major aquifer system. It is clearly of the utmost importance to explore the links between theses aquifer systems and to assess the degree of mixing between the groundwaters. To attain this general objective, the following specific objectives have been either defined in advance or decided as being important during the development of the project: 1. Compile a dataset of water samples from the Yucca Mountain area. This dataset should contain samples from all the potential water types that contribute to the chemistry of the groundwaters in the aquifer systems in the area. 2. Perform a careful total-system exploratory analysis on the initial (raw) dataset in order to identify trends and outliers. 3. Perform a detailed exploratory analysis of each individual hydrofacies with the aim of identifying and eliminating from the raw dataset all the samples heavily affected by processes other than mixing (e.g. water-rock interaction, evaporation, cation exchange). PHREEQC simulations were

  7. An Experiment on the Carbonization of Fuel Compact Matrix Graphite for HTGR

    International Nuclear Information System (INIS)

    Lee, Young Woo; Kim, Joo Hyoung; Cho, Moon Sung

    2012-01-01

    The fuel element for HTGR is manufactured by mixing coated fuel particles with matrix graphite powder and forming into either pebble type or cylindrical type compacts depending on their use in different HTGR cores. The coated fuel particle, the so-called TRISO particle, consists of 500-μm spherical UO 2 particles coated with the low density buffer Pyrolytic Carbon (PyC) layer, the inner and outer high density PyC layer and SiC layer sandwiched between the two inner and outer PyC layers. The coated TRISO particles are mixed with a properly prepared matrix graphite powder, pressed into a spherical shape or a cylindrical compact, and finally heat-treated at about 1800 .deg. C. These fuel elements can have different sizes and forms of compact. The basic steps for manufacturing a fuel element include preparation of graphite matrix powder, over coating the fuel particles, mixing the fuel particles with a matrix powder, carbonizing green compact, and the final high-temperature heat treatment of the carbonized fuel compact. The carbonization is a process step where the binder that is incorporated during the matrix graphite powder preparation step is evaporated and the residue of the binder is carbonized during the heat treatment at about 1073 K, In order to develop a fuel compact fabrication technology, and for fuel matrix graphite to meet the required material properties, it is of extreme importance to investigate the relationship among the process parameters of the matrix graphite powder preparation, fabrication parameters of fuel element green compact and the carbonization condition, which has a strong influence on further steps and the material properties of fuel element. In this work, the carbonization behavior of green compact samples prepared from the matrix graphite powder mixtures with different binder materials was investigated in order to elucidate the behavior of binders during the carbonization heat treatment by analyzing the change in weight, density and its

  8. Ground-based measurement of column-averaged mixing ratios of methane and carbon dioxide in the Sichuan Basin of China by a desktop optical spectrum analyzer

    Science.gov (United States)

    Qin, Xiu-Chun; Nakayama, Tomoki; Matsumi, Yutaka; Kawasaki, Masahiro; Ono, Akiko; Hayashida, Sachiko; Imasu, Ryoichi; Lei, Li-Ping; Murata, Isao; Kuroki, Takahiro; Ohashi, Masafumi

    2018-01-01

    Remote sensing of the atmospheric greenhouse gases, methane (CH4) and carbon dioxide (CO2), contributes to the understanding of global warming and climate change. A portable ground-based instrument consisting of a commercially available desktop optical spectrum analyzer and a small sun tracker has been applied to measure the column densities of atmospheric CH4 and CO2 at Yanting observation station in a mountainous paddy field of the Sichuan Basin from September to November 2013. The column-averaged dry-air molar mixing ratios, XCH4/XCO2, are compared with those retrieved by satellite observations in the Sichuan Basin and by ground-based network observations in the same latitude zone as the Yanting observation station.

  9. Fabrication and mechanical properties of aluminum composite reinforced with functionalized carbon nanotubes

    Science.gov (United States)

    Alavijeh, Elham Zamani; Kokhaei, Saeed; Dehghani, Kamran

    2018-01-01

    Composite aluminum alloy (5000 series) and multi-walled carbon nanotubes (MWCNTs) were made using mechanical alloying, cold press and sintering. The quality of interactions between Al powders and CNTs in the metal matrix composite has a significant effect on mechanical properties. Motivated from the properties of functionalized CNTs, the current study use this material rather than the raw type, because of its reactivity. Besides, a poly-vinyl-alcohol pre-mixing is done, the aim of which is to enhance mixing process. The functionalized carbon nanotubes ware made by chemically method through refluxing with nitric acid. By this method functional groups have been created on CNTs surfaces. 1% and 3% functionalized carbon nanotubes were manufactured using the aforementioned method. To provide unbiased comparisons, 1% and 3% with raw CNTs and pure aluminum is produced with same manner. The numerical experiments affirm the superiority of the functionalized carbon nano-tubes in terms of the relative density and hardness of nanocomposites. As a final activity, the Fourier transformation infrared spectroscopy and field emission scanning electron microscopy techniques were used to characterize the carbon nanotubes and the powders.

  10. Spatiotemporal variation of radon and carbon dioxide concentrations in an underground quarry: coupled processes of natural ventilation, barometric pumping and internal mixing.

    Science.gov (United States)

    Perrier, Frédéric; Richon, Patrick

    2010-04-01

    Radon-222 and carbon dioxide concentrations have been measured during several years at several points in the atmosphere of an underground limestone quarry located at a depth of 18 m in Vincennes, near Paris, France. Both concentrations showed a seasonal cycle. Radon concentration varied from 1200 to 2000 Bq m(-3) in summer to about 800-1400 Bq m(-3) in winter, indicating winter ventilation rates varying from 0.6 to 2.5 x 10(-6) s(-1). Carbon dioxide concentration varied from 0.9 to 1.0% in summer, to about 0.1-0.3% in winter. Radon concentration can be corrected for natural ventilation using temperature measurements. The obtained model also accounts for the measured seasonal variation of carbon dioxide. After correction, radon concentrations still exhibit significant temporal variation, mostly associated with the variation of atmospheric pressure, with coupling coefficients varying from -7 to -26 Bq m(-3) hPa(-1). This variation can be accounted for using a barometric pumping model, coupled with natural ventilation in winter, and including internal mixing as well. After correction, radon concentrations exhibit residual temporal variation, poorly correlated between different points, with standard deviations varying from 3 to 6%. This study shows that temporal variation of radon concentrations in underground cavities can be understood to a satisfactory level of detail using non-linear and time-dependent modelling. It is important to understand the temporal variation of radon concentrations and the limitations in their modelling to monitor the properties of natural or artificial underground settings, and to be able to assess the existence of new processes, for example associated with the preparatory phases of volcanic eruptions or earthquakes. Copyright 2009 Elsevier Ltd. All rights reserved.

  11. Adsorption kinetics of Escherichia Coli on different Carbon Nanoforms

    Directory of Open Access Journals (Sweden)

    Md. Shamimul Haque Choudhury

    2012-03-01

    Full Text Available Adsorption of Escherichia coli (E. Coli bacterial cells on different carbon nanoforms (i.e. Single walled carbon nanotube (SWCNT, Multiwalled Carbon nanotube (MWCNT, graphite and mixedFullerene aggregates is studied. The diffusivities of pure cultures of E. Coli cells in SWCNT aggregates, MWCN aggregates, Graphite aggregates and Mixed Fullerenes was observed to be 1.5×10-9 cm2/s, 0.55×10-9 cm2/s, 0.8×10-9 cm2/s, and 1.016×10-9 cm2/s, respectively. In addition to batch adsorption studies, optical microscopy studies were also performed. The results suggest that diffusion kinetics ofbacterial cells depends on the concentration and average diameter of the nano-carbon aggregates and also on the type of material used. Diffusivity of E. Coli. in SWCNT was observed to be highest and isabout three times greater than for MWCNT, about two times greater than for graphite and about 1.5 times greater than for Fullerene aggregates. SWCNT seems to be best candidates (amongst the othermaterials studied for adsorption of microorganisms – paying their way for application towards microorganisms filters and for biosensors (where it is desired to simultaneously detect and capture bio-threat agents.

  12. Crosslinkable mixed matrix membranes with surface modified molecular sieves for natural gas purification: I. Preparation and experimental results

    KAUST Repository

    Ward, Jason K.

    2011-07-01

    Dense film mixed matrix membranes (MMMs) comprised of SSZ-13 dispersed in a crosslinkable polyimide (PDMC) were fabricated and evaluated for carbon dioxide/methane separations. MMMs containing 25% (w/w) as-received (AR) SSZ-13 exhibited a carbon dioxide permeability of 153 Barrers with a carbon dioxide/methane ideal selectivity of 34.7 at 65. psia and 35 °C. This represents a permeability enhancement of 129% and a decline in selectivity of 4.7% over neat PDMC (PCO2=66.9 Barrers, αCO2/CH4=36.4). A sieve surface modification procedure was developed with the aim of improving SSZ-13/PDMC MMM transport properties. MMMs containing 25% (w/w) surface modified (SM) SSZ-13 exhibited a carbon dioxide permeability of 148 Barrers and carbon dioxide/methane selectivity of 38.9 at 65. psia and 35 °C, representing enhancements in both permeability and selectivity of 121% and 6.9%, respectively. Mixed gas permeation analyses of MMMs containing SM-SSZ-13 using a 10% carbon dioxide/90% methane mixture shows that permeability and selectivity enhancements of 47% and 13%, respectively, over neat PDMC are possible at 700. psia and 35 °C. © 2011 Elsevier B.V.

  13. Determination of the origin of dissolved inorganic carbon in groundwater around a reclaimed landfill in Otwock using stable carbon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Porowska, Dorota, E-mail: dorotap@uw.edu.pl

    2015-05-15

    Highlights: • Research showed the origin of DIC in the groundwater around a reclaimed landfill. • Carbon isotope was used to evaluate the contributions of carbon from different sources. • The leachate-contaminated water was isotopically distinct from the natural groundwater. • DIC in the natural groundwater comes from organic matter and dissolution of carbonates. • In the contaminated water, DIC comes from organic matter in the aquifer and landfill. - Abstract: Chemical and isotopic analyses of groundwater from piezometers located around a reclaimed landfill in Otwock (Poland) were performed in order to trace the origin of dissolved inorganic carbon (DIC) in the groundwater. Due to differences in the isotopic composition of carbon from different sources, an analysis of stable carbon isotopes in the groundwater, together with the Keeling plot approach and a two-component mixing model allow us to evaluate the relative contributions of carbon from these sources in the groundwater. In the natural (background) groundwater, DIC concentrations and the isotopic composition of DIC (δ{sup 13}C{sub DIC}) comes from two sources: decomposition of organic matter and carbonate dissolution within the aquifer sediments, whereas in the leachate-contaminated groundwater, DIC concentrations and δ{sup 13}C{sub DIC} values depend on the degradation of organic matter within the aquifer sediments and biodegradation of organic matter stored in the landfill. From the mixing model, about 4–54% of the DIC pool is derived from organic matter degradation and 96–46% from carbonate dissolution in natural conditions. In the leachate-contaminated groundwater, about 20–53% of the DIC is derived from organic matter degradation of natural origin and 80–47% from biodegradation of organic matter stored in the landfill. Partial pressure of CO{sub 2} (P CO{sub 2}) was generally above the atmospheric, hence atmospheric CO{sub 2} as a source of carbon in DIC pool was negligible in the

  14. Natural Ocean Carbon Cycle Sensitivity to Parameterizations of the Recycling in a Climate Model

    Science.gov (United States)

    Romanou, A.; Romanski, J.; Gregg, W. W.

    2014-01-01

    Sensitivities of the oceanic biological pump within the GISS (Goddard Institute for Space Studies ) climate modeling system are explored here. Results are presented from twin control simulations of the air-sea CO2 gas exchange using two different ocean models coupled to the same atmosphere. The two ocean models (Russell ocean model and Hybrid Coordinate Ocean Model, HYCOM) use different vertical coordinate systems, and therefore different representations of column physics. Both variants of the GISS climate model are coupled to the same ocean biogeochemistry module (the NASA Ocean Biogeochemistry Model, NOBM), which computes prognostic distributions for biotic and abiotic fields that influence the air-sea flux of CO2 and the deep ocean carbon transport and storage. In particular, the model differences due to remineralization rate changes are compared to differences attributed to physical processes modeled differently in the two ocean models such as ventilation, mixing, eddy stirring and vertical advection. GISSEH(GISSER) is found to underestimate mixed layer depth compared to observations by about 55% (10 %) in the Southern Ocean and overestimate it by about 17% (underestimate by 2%) in the northern high latitudes. Everywhere else in the global ocean, the two models underestimate the surface mixing by about 12-34 %, which prevents deep nutrients from reaching the surface and promoting primary production there. Consequently, carbon export is reduced because of reduced production at the surface. Furthermore, carbon export is particularly sensitive to remineralization rate changes in the frontal regions of the subtropical gyres and at the Equator and this sensitivity in the model is much higher than the sensitivity to physical processes such as vertical mixing, vertical advection and mesoscale eddy transport. At depth, GISSER, which has a significant warm bias, remineralizes nutrients and carbon faster thereby producing more nutrients and carbon at depth, which

  15. Glyphosate Utilization as the Source of Carbon: Isolation and Identification of new Bacteria

    Directory of Open Access Journals (Sweden)

    M. Mohsen Nourouzi

    2011-01-01

    Full Text Available Mixed bacteria from oil palm plantation soil (OPS were isolated to investigate their ability to utilize glyphosate as carbon source. Results showed that approximately all of the glyphosate was converted to aminomethyl-phosphonic acid (AMPA (99.5%. It is worthy to note that mixed bacteria were able to degrade only 2% of AMPA to further metabolites. Two bacterial strains i.e. Stenotrophomonas maltophilia and Providencia alcalifaciens were obtained from enrichment culture. Bacterial isolates were cultured individually on glyphosate as a sole carbon source. It was observed that both isolates were able to convert glyphosate to AMPA.

  16. Preparation of carbon-free TEM microgrids by metal sputtering

    International Nuclear Information System (INIS)

    Janbroers, S.; Kruijff, T.R. de; Xu, Q.; Kooyman, P.J.; Zandbergen, H.W.

    2009-01-01

    A new method for preparing carbon-free, temperature-stable Transmission Electron Microscope (TEM) grids is presented. An 80% Au/20% Pd metal film is deposited onto a 'holey' microgrid carbon supported on standard mixed-mesh Au TEM grids. Subsequently, the carbon film is selectively removed using plasma cleaning. In this way, an all-metal TEM film is made containing the 'same' microgrid as the original carbon film. Although electron transparency of the foil is reduced significantly, the open areas for TEM inspection of material over these areas are maintained. The metal foil can be prepared with various thicknesses and ensures good electrical conductivity. The new Au/Pd grids are stable to at least 775 K under vacuum conditions.

  17. Preparation of carbon-free TEM microgrids by metal sputtering.

    Science.gov (United States)

    Janbroers, S; de Kruijff, T R; Xu, Q; Kooyman, P J; Zandbergen, H W

    2009-08-01

    A new method for preparing carbon-free, temperature-stable Transmission Electron Microscope (TEM) grids is presented. An 80% Au/20% Pd metal film is deposited onto a 'holey' microgrid carbon supported on standard mixed-mesh Au TEM grids. Subsequently, the carbon film is selectively removed using plasma cleaning. In this way, an all-metal TEM film is made containing the 'same' microgrid as the original carbon film. Although electron transparency of the foil is reduced significantly, the open areas for TEM inspection of material over these areas are maintained. The metal foil can be prepared with various thicknesses and ensures good electrical conductivity. The new Au/Pd grids are stable to at least 775K under vacuum conditions.

  18. Characterization of electron beam evaporated carbon films and compound formation on titanium and silicon

    International Nuclear Information System (INIS)

    Luthin, J.; Linsmeier, C.

    2001-01-01

    The formation of carbon-based mixed materials is unavoidable on the plasma-facing components (e.g. first wall and divertor) of fusion devices when carbon is used together with other materials. On the surfaces of these components very different conditions with respect to particle and energy impact occur. To predict the mixed material formation under these conditions the precise knowledge of the fundamental mechanisms governing these interactions is essential. In this paper we present the results of carbon interaction with titanium and silicon, as model substances for metallic and covalent carbides, during thermal treatment. To perform basic studies of the reactions of carbon with different elements, thin carbon films are produced by electron beam evaporation on the different substrates under UHV conditions. All measurements for chemical analysis are performed using X-ray photoelectron spectroscopy (XPS). We discuss first the properties of the deposited carbon films. The carbon films are characterized on inert gold surfaces and are compared to bulk graphite. Annealing of the carbon films up to 970 K leads to a transition from a disordered carbon network into a graphitic structure. Preparation of carbon films at room temperature on titanium or silicon leads to a limited carbide formation at the carbon/substrate interface. Carbon deposited in excess of several monolayers is present in elementary form. Annealing of the samples leads to complete carbidization consuming the available carbon in both cases. Titanium reacts to TiC and additional substoichiometric carbide, silicon forms SiC with exact stoichiometry. (orig.)

  19. Technology Advancements for Active Remote Sensing of Carbon Dioxide from Space using the Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) CarbonHawk Experiment Simulator

    Science.gov (United States)

    Obland, Michael D.; Campbell, Joel; Kooi, Susan; Fan, Tai-Fang; Carrion, William; Hicks, Jonathan; Lin, Bing; Nehrir, Amin R.; Browell, Edward V.; Meadows, Byron; Davis, Kenneth J.

    2018-04-01

    This work describes advances in critical lidar technologies and techniques developed as part of the NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons CarbonHawk Experiment Simulator system for measuring atmospheric column carbon dioxide (CO2) mixing ratios. This work provides an overview of these technologies and results from recent test flights during the NASA Atmospheric Carbon and Transport - America (ACT-America) Earth Venture Suborbital summer 2016 flight campaign.

  20. Land-use change and carbon sinks: Econometric estimation of the carbon sequestration supply function; FINAL

    International Nuclear Information System (INIS)

    Lubowski, Ruben N.; Plantinga, Andrew J.; Stavins, Robert N.

    2001-01-01

    Increased attention by policy makers to the threat of global climate change has brought with it considerable interest in the possibility of encouraging the expansion of forest area as a means of sequestering carbon dioxide. The marginal costs of carbon sequestration or, equivalently, the carbon sequestration supply function will determine the ultimate effects and desirability of policies aimed at enhancing carbon uptake. In particular, marginal sequestration conts are the critical statistic for identifying a cost-effective policy mix to mitigate net carbon dioxide emissions. We develop a framework for conducting an econometric analysis of land use for the forty-eight contiguous United States and employing it to estimate the carbon sequestration supply function. By estimating the opportunity costs of land on the basis of econometric evidence of landowners' actual behavior, we aim to circumvent many of the shortcomings of previous sequestration cost assessments. By conducting the first nationwide econometric estimation of sequestration costs, endogenizing prices for land-based commodities, and estimating land-use transition probabilities in a framework that explicitly considers the range of land-use alternatives, we hope to provide better estimates eventually of the true costs of large-scale carbon sequestration efforts. In this way, we seek to add to understanding of the costs and potential of this strategy for addressing the threat of global climate change

  1. Organic carbon input in shallow groundwater at Aspo, southeastern Sweden

    International Nuclear Information System (INIS)

    Wallin, B.

    1993-01-01

    The variation in carbon and oxygen isotopes in calcite fissure fillings and dissolved carbonate from shallow groundwaters has been examined at Aspo, southeastern Sweden. The shallow water lens is refilled by meteoric water and is considered as an open system. The σ 13 C-signatures of the dissolved carbonate fall within a narrow range of -15.8 to -17.4 per-thousand, indicative of organic an organic carbon source. The low σ 13 C-values suggest that input of soil-CO 2 is the dominating carbon source for the system. σ 13 C and σ 18 O-values in the calcite fissure fillings show a wide range in values with a possible two end-member mixing of early post glacial atmospheric CO 2 dominated system to a present day soil-CO 2 dominating carbon source

  2. Fluoro-Carbonate Solvents for Li-Ion Cells

    International Nuclear Information System (INIS)

    NAGASUBRAMANIAN, GANESAN

    1999-01-01

    A number of fluoro-carbonate solvents were evaluated as electrolytes for Li-ion cells. These solvents are fluorine analogs of the conventional electrolyte solvents such as dimethyl carbonate, ethylene carbonate, diethyl carbonate in Li-ion cells. Conductivity of single and mixed fluoro carbonate electrolytes containing 1 M LiPF(sub 6) was measured at different temperatures. These electrolytes did not freeze at -40 C. We are evaluating currently, the irreversible 1st cycle capacity loss in carbon anode in these electrolytes and the capacity loss will be compared to that in the conventional electrolytes. Voltage stability windows of the electrolytes were measured at room temperature and compared with that of the conventional electrolytes. The fluoro-carbon electrolytes appear to be more stable than the conventional electrolytes near Li voltage. Few preliminary electrochemical data of the fluoro-carbonate solvents in full cells are reported in the literature. For example, some of the fluorocarbonate solvents appear to have a wider voltage window than the conventional electrolyte solvents. For example, methyl 2,2,2 trifluoro ethyl carbonate containing 1 M LiPF(sub 6) electrolyte has a decomposition voltage exceeding 6 V vs. Li compared to and lt;5 V for conventional electrolytes. The solvent also appears to be stable in contact with lithium at room temperature

  3. Flexural Properties of Activated Carbon Filled Epoxy Nano composites

    International Nuclear Information System (INIS)

    Khalil, H.P.S.A.; Khalil, H.P.S.A.; Alothman, O.Y.; Paridah, M.T.; Zainudin, E.S.

    2014-01-01

    Activated carbon (AC) filled epoxy nano composites obtained by mixing the desired amount of nano AC viz., bamboo stem, oil palm empty fruit bunch, and coconut shell from agricultural biomass with the epoxy resin. Flexural properties of activated carbons filled epoxy nano composites with 1 %, and 5 % filler loading were measured. In terms of flexural strength and modulus, a significant increment was observed with addition of 1 % vol and 5 % vol nano-activated carbon as compared to neat epoxy. The effect of activated carbon treated by two chemical agents (potassium hydroxide and phosphoric acid) on the flexural properties of epoxy nano composites were also investigated. Flexural strength of activated carbon-bamboo stem, activated carbon-oil palm, and activated carbon-coconut shell reinforced epoxy nano composites showed almost same value in case of 5 % potassium hydroxide activated carbon. Flexural strength of potassium hydroxide activated carbon-based epoxy nano composites was higher than phosphoric acid activated carbon. The flexural toughness of both the potassium hydroxide and phosphoric acid activated carbon reinforced composites range between 0.79 - 0.92 J. It attributed that developed activated carbon filled epoxy nano composites can be used in different applications. (author)

  4. Optimization of Rhodium-Based Catalysts for Mixed Alcohol Synthesis – 2012 Progress Report

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, Mark A.; Gray, Michel J.; Albrecht, Karl O.; Thompson, Becky L.

    2012-11-01

    Pacific Northwest National Laboratory has been conducting research to investigate the feasibility of producing mixed alcohols from biomass-derived synthesis gas (syngas). In recent years, this research has primarily involved the further development of catalysts containing rhodium and manganese based on the results of earlier catalyst screening tests. Testing continued in FY 2012 to further improve the Ir-promoted RhMn catalysts on both silica and carbon supports for producing mixed oxygenates from synthesis gas. This testing re-examined selected alternative silica and carbon supports to follow up on some uncertainties in the results with previous test results. Additional tests were conducted to further optimize the total and relative concentrations of Rh, Mn, and Ir, and to examine selected promoters and promoter combinations based on earlier results. To establish optimum operating conditions, the effects of the process pressure and the feed gas composition also were evaluated.

  5. Argonne National Laboratory's photo-oxidation organic mixed waste treatment system - installation and startup testing

    International Nuclear Information System (INIS)

    Shearer, T.L.; Nelson, R.A.; Torres, T.; Conner, C.; Wygmans, D.

    1997-01-01

    This paper describes the installation and startup testing of the Argonne National Laboratory (ANL-E) Photo-Oxidation Organic Mixed Waste Treatment System. This system will treat organic mixed (i.e., radioactive and hazardous) waste by oxidizing the organics to carbon dioxide and inorganic salts in an aqueous media. The residue will be treated in the existing radwaste evaporators. The system is installed in the Waste Management Facility at the ANL-E site in Argonne, Illinois. 1 fig

  6. A Multiperiod Supply Chain Network Design Considering Carbon Emissions

    Directory of Open Access Journals (Sweden)

    Yang Peng

    2016-01-01

    Full Text Available This paper introduces a mixed integer linear programming formulation for modeling and solving a multiperiod one-stage supply chain distribution network design problem. The model is aimed to minimize two objectives, the total supply chain cost and the greenhouse gas emissions generated mainly by transportation and warehousing operations. The demand forecast is known for the planning horizon and shortage of demand is allowed at a penalty cost. This scenario must satisfy a minimum service level. Two carbon emission regulatory policies are investigated, the tax or carbon credit and the carbon emission cap. Computational experiments are performed to analyze the trade-offs between the total cost of the supply chain, the carbon emission quantity, and both carbon emission regulatory policies. Results demonstrate that for a certain range the carbon credit price incentivizes the reduction of carbon emissions to the environment. On the other hand, modifying the carbon emission cap inside a certain range could lead to significant reductions of carbon emission while not significantly compromising the total cost of the supply chain.

  7. Influence of activated carbon amendment on the accumulation and elimination of PCBs in the earthworm Eisenia fetida

    International Nuclear Information System (INIS)

    Paul, Piuly; Ghosh, Upal

    2011-01-01

    In this study we investigated the use of activated carbon (AC) as a soil amendment for reducing bioavailability of polychlorinated biphenyls (PCBs) to the earthworm Eisenia fetida. Artificial soil was contaminated with PCBs and used in bioaccumulation experiments fresh or after aging for 19 months. PCB bioaccumulation in earthworms was reduced by 68% when AC was placed as a layer without mixing and by 94% when AC was manually mixed into the soil. Aging of the same AC mixed soil for 19 months resulted in an overall reduction of 99% in PCB biouptake. AC-treated aged soil also showed two orders of magnitude lower equilibrium aqueous concentrations of PCBs compared to untreated aged soils. The findings from this study indicate that application of engineered sorbents like AC to PCB impacted soils may greatly reduce PCB uptake at the base of the terrestrial food chain. - Graphical abstract: Display Omitted Highlights: → Activated carbon studied as a sorbent for PCB impacted unsaturated soil. → Bioaccumulation of PCB greatly reduced in earthworms after carbon amendment. → Aging of the activated carbon amended soil further reduced bioaccumulation. → Activated carbon can be used for in-situ stabilization of PCB impacted soil. - Addition of activated carbon to PCB impacted soil reduces equilibrium aqueous concentrations and uptake at the base of the terrestrial food chain.

  8. Ocean bio-geophysical modeling using mixed layer-isopycnal general circulation model coupled with photosynthesis process

    Digital Repository Service at National Institute of Oceanography (India)

    Nakamoto, S.; Saito, H.; Muneyama, K.; Sato, T.; PrasannaKumar, S.; Kumar, A.; Frouin, R.

    -chemical system that supports steady carbon circulation in geological time scale in the world ocean using Mixed Layer-Isopycnal ocean General Circulation model with remotely sensed Coastal Zone Color Scanner (CZCS) chlorophyll pigment concentration....

  9. Carbonization kinetics of La2O3-Mo cathode materials

    International Nuclear Information System (INIS)

    Jinshu, W.; Meiling, Z.; Tieyong, Z.; Jiuxing, Z.; Zuoren, N.

    2001-01-01

    The carbonization kinetics of La 2 O 3 -Mo cathode materials has been studied by thermal analysis method. Three-stage model of the carbonization has been presented in this paper. The carbonization rate is initially controlled by chemical reaction, then controlled by chemical reaction mixed with diffusion, finally controlled by diffusion. After the initial experimental data are processed according to this model, the correlation coefficients of the kinetic curves are satisfactory. The apparent activation energy of carbonization of La 2 O 3 -Mo cathode materials has been obtained. At the same time, we have deduced the empirical expressions of the amount of weight increased per unit area after carbonization, temperature and time in the temperature range 1393 K - 1493 K. (author)

  10. Changes in ocean circulation and carbon storage are decoupled from air-sea CO2 fluxes

    OpenAIRE

    A. Gnanadesikan; I. Marinov

    2010-01-01

    The spatial distribution of the air-sea flux of carbon dioxide is a poor indicator of the underlying ocean circulation and of ocean carbon storage. The weak dependence on circulation arises because mixing-driven changes in solubility-driven and biologically-driven air-sea fluxes largely cancel out. This cancellation occurs because mixing driven increases in the poleward residual mean circulation results in more transport of both remineralized nutrients and heat from low to high latitudes. By ...

  11. Natural Gas, Wind and Nuclear Options for Generating Electricity in a Carbon Constrained World

    NARCIS (Netherlands)

    Kooten, van G.C.

    2012-01-01

    A linear programming model is used to examine the impact of carbon taxes on the optimal generation mix in the Alberta electrical system. The model permits decommissioning of generating assets with high carbon dioxide emissions and investment in new gas-fired, wind and, in some scenarios, nuclear

  12. Effect of carbon black on electrical and rheological properties of graphite nanoplatelets/poly(ethylene-butyl acrylate composites

    Directory of Open Access Journals (Sweden)

    H. Oxfall

    2015-01-01

    Full Text Available The effect of adding carbon black on the electrical and rheological properties of graphite nanoplatelets/poly(ethylene-butyl acrylate copolymer composites produced via melt or solution mixing was studied. By adding a small amount of low- or high-structured carbon black to the nanocomposite, the electrical percolation threshold decreased and the final conductivity (at higher filler contents increased. The effect on the percolation threshold was significantly stronger in case of the high-structured carbon black where replacing 10 wt% of the total filler content with carbon black instead of graphite nanoplatelets reduced the electrical percolation threshold from 6.9 to 4.6 vol%. Finally, the solution mixing process was found to be more efficient leading to a lower percolation threshold. For the composites containing high-structured carbon black, graphite nanoplatelets and their hybrids there was a quite reasonable correlation between the electrical and rheological percolation thresholds.

  13. Experimental and numerical investigation of the mixed-mode delamination in Arcan laminated specimens

    International Nuclear Information System (INIS)

    Choupani, Naghdali

    2008-01-01

    This paper investigates mixed-mode interlaminar fracture behaviour in woven carbon fibre/polyetherimide (CF/PEI) thermoplastic composite material based on experimental and numerical analyses. Experiments were conducted on modified Arcan specimens using the special test loading device. By varying the loading angle from 0 o to 90 o , pure mode-I, pure mode-II and a wide range of mixed-mode data were obtained experimentally. Using the finite-element results, correction factors were applied to the CF/PEI fracture specimen. By employing experimentally measured critical loads and the aid of the finite-element method, mixed-mode interlaminar fracture toughness for the composite under consideration determined. The failure response of CF/PEI composite was compared to the different mixed-mode failure criteria, and the best criterion was selected. The fracture surfaces of the CF/PEI composite under different mixed-mode loading conditions were examined by optical and scanning electron microscopy to gain insight into the failure responses

  14. Actions on climate change, Intended Reducing carbon emissions in China via optimal industry shifts: Toward hi-tech industries, cleaner resources and higher carbon shares in less-develop regions

    International Nuclear Information System (INIS)

    Fu, Xue; Lahr, Michael; Yaxiong, Zhang; Meng, Bo

    2017-01-01

    This paper uses an optimal interregional input-output model to focus on how interregional industrial shifts alone might enable China to reduce carbon intensity instead of national shifts. The optimal industry shifts assure integration of all regions by regional products and goods in which carbon emissions are embodied via energy consumption. Generally speaking, high-tech industries concentrate in affluent regions to replace construction. Selected services increase output shares across most of regions. Meanwhile, energy-intensive manufacturing, rather than agriculture, decrease their shares to achieve the national annual growth constrained by nation’s carbon targets. Due to the need to decelerate energy use, carbon intensity goal puts particularly extreme pressure on less-developed regions to shutter heavy industries. Explicit shifts toward cleaner resources and renewable energy appear to be quite important for coal mines in Central China. - Highlights: • The model optimizes GDP constrained by industry-based emissions targets. • Scenario on carbon intensity, growth rate, energy mix, and technology advance. • Interregional I-O table informs technology, industry mix, and interregional trade. • China could raise the output of high-tech in South Coast and of selected services. • Shifts toward cleaner resources and renewable energy are important in the Central.

  15. Ecomorphological and taphonomic gradients in clypeasteroid-dominated echinoid assemblages along a mixed siliciclastic-carbonate shelf from the early Miocene of northern Sardinia, Italy

    Directory of Open Access Journals (Sweden)

    Andrea Mancosu

    2017-09-01

    Full Text Available Clypeasteroid echinoids are widespread and abundant within Miocene sedimentary sequences of the Mediterranean area within both siliciclastic and carbonate deposits. Herein, three clypeasteroid-dominated echinoid assemblages from the mixed siliciclastic-carbonate succession of the Mores Formation (lower Miocene cropping out within the Porto Torres Basin (northern Sardinia are described. These assemblages were compared to previously described clypeasteroid-bearing deposits from the Miocene of northern Sardinia with the purpose of investigating their palaeoecology and taphonomy along a shelf gradient. These goals are accomplished by various methods including (i logging sedimentary facies, (ii analysing the functional morphology of sea urchin skeletons, (iii comparing the relative abundance of taxa and taphonomic features, and (iv studying associated fauna, flora, and trace fossils. The clypeasteroid-bearing deposits differ greatly with respect to echinoid diversity, accompanying fauna and flora, sedimentological signatures, and taphonomic features. They also show variations in depositional environments and the mechanism of formation of the deposits. Three different shelf settings are distinguished: littoral, inner sublittoral, and outer sublittoral environments. Furthermore, an ecomorphological gradient along the shelf is recognized with respect to echinoid taxa and their morphologies. This gradient ranges from shallow water to a moderately deep shelf and is interpreted with respect to both abiotic and biotic factors as well as the taphonomy of the echinoid tests.

  16. Preparation of carbon-free TEM microgrids by metal sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Janbroers, S., E-mail: stephan.janbroers@albemarle.com [Albemarle Catalysts B.V., Nieuwendammerkade 1-3, 1030 BE, Amsterdam (Netherlands); Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Kruijff, T.R. de; Xu, Q. [Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Kooyman, P.J. [DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL, Delft (Netherlands); Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands); Zandbergen, H.W. [Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft (Netherlands)

    2009-08-15

    A new method for preparing carbon-free, temperature-stable Transmission Electron Microscope (TEM) grids is presented. An 80% Au/20% Pd metal film is deposited onto a 'holey' microgrid carbon supported on standard mixed-mesh Au TEM grids. Subsequently, the carbon film is selectively removed using plasma cleaning. In this way, an all-metal TEM film is made containing the 'same' microgrid as the original carbon film. Although electron transparency of the foil is reduced significantly, the open areas for TEM inspection of material over these areas are maintained. The metal foil can be prepared with various thicknesses and ensures good electrical conductivity. The new Au/Pd grids are stable to at least 775 K under vacuum conditions.

  17. Global W`o'rming and Darwin Revisited: Quantifying Soil Mixing Rates by Non-native Earthworms in Fennoscandian Boreal and Arctic Ecosystems

    Science.gov (United States)

    Wackett, A. A.; Yoo, K.; Cameron, E. K.; Olid, C.; Klaminder, J.

    2017-12-01

    Fennoscandian boreal and arctic ecosystems represent some of the most pristine environments in Europe and store sizeable quantities of soil carbon. Both ecosystems may have evolved without native earthworms since the last glaciation, but are now increasingly subject to arrivals of novel geoengineering earthworm species due to human activities. As a result, invaded areas are devoid of the typical thick organic horizon present in earthworm free forest soils and instead contain carbon-rich mineral (A-horizon) soils at the surface. How rapidly this transition occurs and how it affects the fate of soil organic carbon (SOC) pools is not well known. In this study, we quantify the rates at which earthworm-mediated mixing of forest soils proceeds in these formerly glaciated landscapes. We infer soil mass fluxes using the vertical distribution of 210Pb in soils from Fennoscandia (N=4) and North America (N=1) and quantify annual mixing velocities as well as vertical fluxes of organic and mineral matter throughout the upper soil profiles. Across the sites, mixing velocities generally increase with increasing earthworm biomass and functional group diversity, and our annual mixing rates closely align with those predicted by Darwin for earthworm-engineered ecosystems in the UK 130 years earlier. Reduction of the O-horizon is concomitant with a decrease in surface SOC contents. However, we observe minimal changes to SOC inventories with earthworm invasion across the sites, reflecting the upward translocation of mineral soil and accompanying increase in soil bulk densities. Thus, the reduction or depletion of organic horizon by exotic earthworms does not necessarily involve loss of SOC via earthworm-accelerated decomposition, but is rather compensated for by physical mixing of organic matter and minerals, which may facilitate stabilizing organo-mineral interactions. This work constitutes an important step to elucidate how non-native earthworms impact SOC inventories and potentially

  18. Carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Hennebutte, H G; Goutal, E

    1921-07-04

    Materials such as coal, peat, or schist are subjected to a rising temperature in successive stages in apparatus in which the distillation products are withdrawn at each stage. For example in a three-stage process, the acid products of the first or low-temperature stage are fixed in a suitable reagent, the basic products from a second or higher-temperature stage are absorbed in an acid reagent, hydrocarbons being retained by solvents, while the third are subjected to a pyrogenation process carried out in a closed vessel. Wherein the material is subjected in stages to a rising temperature, the gasified products being withdrawn at each stage, and are prevented as far as possible from mixing with the carbonized products.

  19. Quantifying the uncertainties of advection and boundary layer dynamics on the diurnal carbon dioxide budget

    NARCIS (Netherlands)

    Pino, D.; Kaikkonen, J.P.; Vilà-Guerau de Arellano, J.

    2013-01-01

    [1] We investigate the uncertainties in the carbon dioxide (CO2) mixing ratio and inferred surface flux associated with boundary layer processes and advection by using mixed-layer theory. By extending the previous analysis presented by Pino et al. (2012), new analytical expressions are derived to

  20. Carbon and nitrogen in Type 2 supernova diamonds

    Science.gov (United States)

    Clayton, Donald D.; Eleid, Mounib; Brown, Lawrence E.

    1993-03-01

    Abundant diamonds found in meteorites seem either to have condensed within supernova interiors during their expansions and coolings or to have been present around those explosions. Either alternative allows implantation of Xe-HL prior to interstellar mixing. A puzzling feature is the near normalcy of the carbon isotopes, considering that the only C-rich matter, the He-burning shell, is pure C-12 in that region. That last fact has caused many to associate supernova carbon with C-12 carbon, so that its SUNOCONS have been anticipated as very C-12-rich. We show that this expectation is misleading because the C-13-rich regions of Type 2's have been largely overlooked in this thinking. We here follow the idea that the diamonds nucleated in the C-12-rich He shell, the only C-rich site for nucleation, but then attached C-13-rich carbon during turbulent encounters with overlying C-13-rich matter. That is, the initial diamonds continued to grow during the same collisional encounters that cause the Xe-HL implantation. Instead of interacting with the small carbon mass having 13/12 = 0.2 in the upper He zone, however, we have calculated the remnants of the initial H-burning core, which left behind C-13-rich matter as it receded during core hydrogen burning. Howard et al. described why the velocity mixing would be essential to understanding the implantation of both the Xe-H and Xe-L components. Velocity mixing is now known to occur from the X-ray and gamma-ray light curves of supernova 1987A. Using the stellar evolution code developed at Goettingen, we calculated at Clemson the evolution of a grid of massive stars up to the beginning of core He burning. We paid attention to all H-burning reactions throughout the star, to the treatment of both convection and semiconvection, and to the recession of the outer boundary of the convective H-burning core as the star expands toward a larger redder state. This program was to generate a careful map of the CNO isotope distribution as He

  1. Linear C32H66 hydrocarbon in the mixed state with C10H22 ...

    Indian Academy of Sciences (India)

    Unknown

    S R Research Laboratory for Studies in Crystallization Phenomena, 10-1-96, ... mixed state with certain shorter chain length homologues (SMOLLENCs), estimated ... Methods. Five hydrocarbons of even carbon numbers, C10, C12, C14, C16 ...

  2. Waste Treatment of Chrome Residue of Chromium Recovery Process Using Calcium Carbonate

    International Nuclear Information System (INIS)

    Endro Kismolo; Prayitno; Nurimaniwathy

    2002-01-01

    The aim of the research was to apply the precipitation technology for the treatment of aqueous wastes of leather tanning industries. The chrome liquid wastes taken was the effluent from the residue of the chromium recovery process using magnesium oxide. The precipitant used was calcium carbonate. The experiments was performed by adjusting the concentration of calcium carbonate from 50 ppm, 100 ppm, 150 ppm, 200 ppm, 250 ppm, 300 ppm, 350 ppm to 400 ppm. The stirring speed was varied from 50 rpm, 75 rpm, 100 rpm, 125 rpm, 150 rpm, 175 rpm to 200 rpm. The time of mixing was varied from 30 minutes, 60 minutes, 90 minutes, 120 minutes, 150 minutes, 175 minutes and 200 minutes. The result from the experiments lead to the best condition obtained were the concentration of precipitant was 300 ppm, flow rates of mixing was 125 rpm and time of mixing was 60 minutes. At this condition the separations efficiency of chrome obtained was 99.985%. (author)

  3. Hydrogen evolution from water using solid carbon and light energy

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, T; Sakata, T

    1979-11-15

    Hydrogen is produced from water vapour and solid carbon when mixed powders of TiO2, RuO2 and active carbon exposed to water vapor at room temperature, or up to 80 C, are illuminated. At 80 C, the rate of CO and COat2 formation increased. Therefore solar energy would be useful here as a combination of light energy and heat energy. Oxygen produced on the surface of the photocatalyst has a strong oxidising effect on the carbon. It is suggested that this process could be used for coal gasification and hydrogen production from water, accompanied by storage of solar energy.

  4. Production and characterization of supersonic carbon cluster beams

    International Nuclear Information System (INIS)

    Rohlfing, E.A.; Cox, D.M.; Kaldor, A.

    1984-01-01

    Laser vaporization of a substrate within the throat of a pulsed nozzle is used to generate a supersonic beam of carbon clusters. The neutral cluster beam is probed downstream by UV laser photoionization with time-of-flight mass analysis of the resulting photoions. Using graphite as the substrate, carbon clusters C/sub n/ for n = 1--190 have been produced having a distinctly bimodal cluster size distribution: (i) Both even and odd clusters for C/sub n/, 1 + /sub n/ signals are interpreted on the basis of cluster formation and stability arguments. Ionizing laser power dependences taken at several different photon energies are used to roughly bracket the carbon cluster ionization potentials, and, at high laser intensity, to observe the onset of multiphoton fragmentation. By treating the graphite rod with KOH, a greatly altered carbon cluster distribution with mixed carbon/potassium clusters of formula K 2 C/sub 2n/ is produced

  5. Mixing core material into the envelopes of red grants

    International Nuclear Information System (INIS)

    Deupree, R.G.

    1986-01-01

    A discussion is presented of calculations of four core helium flashes in red giant stars. The starting point for these calculations is a point source explosion on the polar axis of a two-dimensional finite difference grid. The amount of residue of the core helium flash mixed into and above the hydrogen shell is calculated at four temperatures for the elements carbon, oxygen, neon, magnesium, silicon, and sulfur. 7 refs., 1 tab

  6. Flexible and conductive waste tire-derived carbon/polymer composite paper as pseudocapacitive electrode

    Science.gov (United States)

    Naskar, Amit K.; Paranthaman, Mariappan Parans; Boota, Muhammad; Gogotsi, Yury

    2018-04-10

    A method of making a supercapacitor from waste tires, includes the steps of providing rubber pieces and contacting the rubber pieces with a sulfonation bath to produce sulfonated rubber; pyrolyzing the sulfonated rubber to produce a tire-derived carbon composite comprising carbon black embedded in rubber-derived carbon matrix comprising graphitized interface portions; activating the tire-derived carbon composite by contacting the tire-derived carbon composite with a specific surface area-increasing composition to increase the specific surface area of the carbon composite to provide an activated tire-derived carbon composite; and, mixing the activated tire-derived carbon composite with a monomer and polymerizing the monomer to produce a redox-active polymer coated, activated tire-derived carbon composite. The redox-active polymer coated, activated tire-derived carbon composite can be formed into a film. An electrode and a supercapacitor are also disclosed.

  7. The carbonate complexation of plutonium(IV)

    International Nuclear Information System (INIS)

    Hobart, D.E.; Palmer, P.D.; Newton, T.W.

    1985-01-01

    Plutonium(IV) carbonate complexes are expected to be of particular importance in typical groundwaters at the Yucca Mountain site of the candidate nuclear waste repository being studied by the Nevada Nuclear Waste Storage Investigations Project. The chemistry of these complexes is also important in the areas of nuclear fuel reprocessing and purification, actinide separations, and environmental studies. This report describes initial experiments performed to determine the identity and equilibrium quotients of plutonium(IV) carbonate complexes. These experiments were performed at pH values between 7.2 and 9.6 using a spectrophotometric method. In addition, a brief review of the published literature on Pu(IV) carbonate complexes is presented. Since Pu(IV) exhibits low solubility in the near-neutral pH range, a complex-competition reaction where citrate ligands compete with carbonate ions for the plutonium will be employed. This will permit us to study the pure carbonate system; study the mixed carbonate/citrate system, and confirm and extend the literature work on the pure citrate system. The current experiments have demonstrated the existence of at least three distinct species in the pH region studied. This work will continue in the extended study of the pure citrate system, followed by the investigation of the citrate/carbonate complex/competition reaction. 9 refs., 4 figs., 2 tabs

  8. Simple Microwave-Assisted Synthesis of Carbon Nanotubes Using Polyethylene as Carbon Precursor

    Directory of Open Access Journals (Sweden)

    N. Kure

    2017-01-01

    Full Text Available In this work, a quick and effective method to synthesize carbon nanotubes (CNTs is reported; a commercial microwave oven of 600 W at 2.45 GHz was utilized to synthesize CNTs from plasma catalytic decomposition of polyethylene. Polyethylene and silicon substrate coated with iron (III nitrate were placed in the reaction chamber to form the synthesis stock. The CNTs were synthesized at 750°C under atmospheric pressure of 0.81 mbar. Raman spectroscopy and field emission scanning electron microscope revealed the quality and entangled bundles of mixed CNTs from which the diameters of the CNTs were calculated to be between 1.03 and 25.00 nm. High resolution transmission electron microscope further showed that the CNTs obtained by this method are graphitized. Energy dispersive X-ray analysis and thermogravimetric analysis revealed above 98% carbon purity.

  9. Autonomous observing strategies for the ocean carbon cycle

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, James K.; Davis, Russ E.

    2000-07-26

    Understanding the exchanges of carbon between the atmosphere and ocean and the fate of carbon delivered to the deep sea is fundamental to the evaluation of ocean carbon sequestration options. An additional key requirement is that sequestration must be verifiable and that environmental effects be monitored and minimized. These needs can be addressed by carbon system observations made from low-cost autonomous ocean-profiling floats and gliders. We have developed a prototype ocean carbon system profiler based on the Sounding Oceanographic Lagrangian Observer (SOLO; Davis et al., 1999). The SOLO/ carbon profiler will measure the two biomass components of the carbon system and their relationship to physical variables, such as upper ocean stratification and mixing. The autonomous observations within the upper 1500 m will be made on daily time scales for periods of months to seasons and will be carried out in biologically dynamic locations in the world's oceans that are difficult to access with ships (due to weather) or observe using remote sensing satellites (due to cloud cover). Such an observational capability not only will serve an important role in carbon sequestration research but will provide key observations of the global ocean's natural carbon cycle.

  10. Systematic investigations on acyclic organic carbonate solvents for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Vetter, J.; Peter, S.; Novak, P.

    2003-03-01

    Electrochemical cycling tests on cells with graphite electrodes and several alkyl methyl carbonates were performed. Experiments with mixed binary solvent electrolytes with ethylene carbonate (EC) showed that the alkyl methyl carbonates H{sub 3}CO(CO)O(CH{sub 2}){sub n}H (n = 3-5) are suitable as co-solvents in lithium-ion batteries. Ternary mixtures of EC, BMC, and propylene carbonate (PC) showed better overall performances than EC/PC electrolytes. The branched isobutyl methyl carbonate (i-BMC) outperforms its linear isomer (BMC) in terms of electrochemical performance. LiPF{sub 6} is superior to LiClO{sub 4} as conducting salt in both EC/BMC and EC/i-BMC mixtures in terms of electrolyte conductivity, rate capability, and cycling stability. (author)

  11. The puzzle of the CNO isotope ratios in asymptotic giant branch carbon stars

    Science.gov (United States)

    Abia, C.; Hedrosa, R. P.; Domínguez, I.; Straniero, O.

    2017-03-01

    Context. The abundance ratios of the main isotopes of carbon, nitrogen and oxygen are modified by the CNO-cycle in the stellar interiors. When the different dredge-up events mix the burning material with the envelope, valuable information on the nucleosynthesis and mixing processes can be extracted by measuring these isotope ratios. Aims: Previous determinations of the oxygen isotopic ratios in asymptotic giant branch (AGB) carbon stars were at odds with the existing theoretical predictions. We aim to redetermine the oxygen ratios in these stars using new spectral analysis tools and further develop discussions on the carbon and nitrogen isotopic ratios in order to elucidate this problem. Methods: Oxygen isotopic ratios were derived from spectra in the K-band in a sample of galactic AGB carbon stars of different spectral types and near solar metallicity. Synthetic spectra calculated in local thermodynamic equillibrium (LTE) with spherical carbon-rich atmosphere models and updated molecular line lists were used. The CNO isotope ratios derived in a homogeneous way, were compared with theoretical predictions for low-mass (1.5-3 M⊙) AGB stars computed with the FUNS code assuming extra mixing both during the RGB and AGB phases. Results: For most of the stars the 16O/17O/18O ratios derived are in good agreement with theoretical predictions confirming that, for AGB stars, are established using the values reached after the first dredge-up (FDU) according to the initial stellar mass. This fact, as far as the oxygen isotopic ratios are concerned, leaves little space for the operation of any extra mixing mechanism during the AGB phase. Nevertheless, for a few stars with large 16O/17O/18O, the operation of such a mechanism might be required, although their observed 12C/13C and 14N/15N ratios would be difficult to reconcile within this scenario. Furthermore, J-type stars tend to have lower 16O/17O ratios than the normal carbon stars, as already indicated in previous studies

  12. Increased topsoil carbon stock across China's forests.

    Science.gov (United States)

    Yang, Yuanhe; Li, Pin; Ding, Jinzhi; Zhao, Xia; Ma, Wenhong; Ji, Chengjun; Fang, Jingyun

    2014-08-01

    Biomass carbon accumulation in forest ecosystems is a widespread phenomenon at both regional and global scales. However, as coupled carbon-climate models predicted, a positive feedback could be triggered if accelerated soil carbon decomposition offsets enhanced vegetation growth under a warming climate. It is thus crucial to reveal whether and how soil carbon stock in forest ecosystems has changed over recent decades. However, large-scale changes in soil carbon stock across forest ecosystems have not yet been carefully examined at both regional and global scales, which have been widely perceived as a big bottleneck in untangling carbon-climate feedback. Using newly developed database and sophisticated data mining approach, here we evaluated temporal changes in topsoil carbon stock across major forest ecosystem in China and analysed potential drivers in soil carbon dynamics over broad geographical scale. Our results indicated that topsoil carbon stock increased significantly within all of five major forest types during the period of 1980s-2000s, with an overall rate of 20.0 g C m(-2) yr(-1) (95% confidence interval, 14.1-25.5). The magnitude of soil carbon accumulation across coniferous forests and coniferous/broadleaved mixed forests exhibited meaningful increases with both mean annual temperature and precipitation. Moreover, soil carbon dynamics across these forest ecosystems were positively associated with clay content, with a larger amount of SOC accumulation occurring in fine-textured soils. In contrast, changes in soil carbon stock across broadleaved forests were insensitive to either climatic or edaphic variables. Overall, these results suggest that soil carbon accumulation does not counteract vegetation carbon sequestration across China's forest ecosystems. The combination of soil carbon accumulation and vegetation carbon sequestration triggers a negative feedback to climate warming, rather than a positive feedback predicted by coupled carbon-climate models

  13. Mixing ratio sensor of alcohol mixed fuel

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Shigeru; Matsubara, Yoshihiro

    1987-08-07

    In order to improve combustion efficiency of an internal combustion engine using gasoline-alcohol mixed fuel and to reduce harmful substance in its exhaust gas, it is necessary to control strictly the air-fuel ratio to be supplied and the ignition timing and change the condition of control depending upon the mixing ratio of the mixed fuel. In order to detect the mixing ratio of the mixed fuel, the above mixing ratio has so far been detected by casting a ray of light to the mixed fuel and utilizing a change of critical angle associated with the change of the composition of the fluid of the mixed fuel. However, in case when a light emitting diode is used for the light source above, two kinds of sensors are further needed. Concerning the two kinds of sensors above, this invention offers a mixing ratio sensor for the alcohol mixed fuel which can abolish a temperature sensor to detect the environmental temperature by making a single compensatory light receiving element deal with the compensation of the amount of light emission of the light emitting element due to the temperature change and the compensation of the critical angle caused by the temperature change. (6 figs)

  14. Contributions for the international conference on carbon and graphite CARBON '88

    International Nuclear Information System (INIS)

    Delle, W.

    1988-08-01

    This report is the compilation of three papers prepared by the Kernforschungsanlage Juelich GmbH (KFA) in collaboration with other partners for the International Conference CARBON '88. The topics were as follows: 1.) Fracture toughness of fast neutron irradiated graphite (W. Delle, H. Derz, G. Kleist, H. Nickel, W. Thiele); 2.) The irradiation creep characteristics of graphite to high fluences (C.R. Kennedy, M. Cundy, G. Kleist); and 3.) New silicon carbide materials starting with the Coat-Mix procedure (H.K. Luhleich, K. Bach, F.J. Dias, M. Kampel, F. Koch, H. Nickel). (orig./MM)

  15. The short-term effect on carbonate parameters from hurricanes Harvey, Irma, and Maria.

    Science.gov (United States)

    Jonsson, B. F.; Salisbury, J., II; Melendez Oyola, M.

    2017-12-01

    Tropical storms and hurricanes are events with potentially extreme impacts on ocean conditions. Strong winds generating vigorous vertical mixing and extensive precipitation affect both temperature and salinity in the mixed layer. The surface temperature, for example, decreased several degrees C in the wake of both hurricanes Irma and Maria. While it is clear that the physical state of the surface ocean is affected by hurricanes, how such storms affect carbonate system variability is still an open question. Changes in temperature and salinity combined with extreme winds create the potential for changes in solubility of pCO2, and large net fluxes of CO2 across the air-sea interface. A deepening of the mixed layer from wind-driven mixing may further affect the carbonate system, as sub-surface waters rich in dissolved inorganic carbon and nutrients are entrained to the surface. To examine these process, we evaluate simulated fields of temperature and salinity (from a 1/12° global data assimilated General Circulation Model), satellite ocean color and wind speed data within the context of a conceptual box model. Our model is compared to observed pCO2, wind speed, temperature and salinity data from buoyed assets that survived the storms. We address total CO2 fluxes, the relative effects temperature, salinity and biology on the carbonate system, and the time scales over which the system is "restored" to its initial state. We explore the connection between the magnitude of perturbation and the length of time it takes for the system to recover, and observe recovery over time scales lasting from days to weeks depending on the storm. Although not observed in these data, we speculate that depending on the buoyancy frequency, recovery elsewhere could take place over monthly time scales, raising the potential that hurricanes could exacerbate or alleviate environmental stresses on calcifying marine organisms.

  16. Characteristics of Sodium Polyacrylate/Nano-Sized Carbon Hydrogel for Biomedical Patch.

    Science.gov (United States)

    Park, Jong-Kyu; Seo, Sun-Kyo; Cho, Seungkwan; Kim, Han-Sung; Lee, Chi-Hwan

    2018-03-01

    Conductive hydrogels were prepared for biomedical patch in order to improve the electrical conductivity. Sodium polyacrylate and nano-sized carbon were mixed and fabricated by aqueous solution gelation process in various contents of nano-sized carbon with 0.1, 0.5, 1.0 and 2.0 wt%. Sodium polyacrylate/nano-sized carbon conductive hydrogels were investigated by molecular structure, surface morphology and electrical conductivity. The conductivity of the hydrogel/nano-sized carbon conductive hydrogel proved to be 10% higher than conductive hydrogel without nano-sized carbon. However, it was founded that conductive hydrogels with nano-sized carbon content from 0.5 up to 2.0 wt% were remarkably decreased. This may be due to the non-uniform distribution of nano-sized carbon, resulting from agglomerates of nano-sized carbon. The developed hydrogel is intended for use in the medical and cosmetic fields that is applicable to supply micro-current from device to human body.

  17. Meteorological controls on the diurnal variability of carbon monoxide mixing ratio at a mountaintop monitoring site in the Appalachian Mountains

    Directory of Open Access Journals (Sweden)

    Temple R. Lee

    2015-05-01

    Full Text Available The variability of trace gases such as carbon monoxide (CO at surface monitoring stations is affected by meteorological forcings that are particularly complicated over mountainous terrain. A detailed understanding of the impact of meteorological forcings on trace gas variability is challenging, but is vital to distinguish trace gas measurements affected by local pollutant sources from measurements representative of background mixing ratios. In the present study, we investigate the meteorological and CO characteristics at Pinnacles (38.61 N, 78.35 W, 1017 m above mean sea level, a mountaintop monitoring site in northwestern Virginia, USA, in the Appalachian Mountains, from 2009 to 2012, and focus on understanding the dominant meteorological forcings affecting the CO variability on diurnal timescales. The annual mean diurnal CO cycle shows a minimum in the morning between 0700 and 0900 LST and a maximum in the late afternoon between 1600 and 2000 LST, with a mean (median daily CO amplitude of 39.2±23.7 ppb (33.2 ppb. CO amplitudes show large day-to-day variability. The largest CO amplitudes, in which CO mixing ratios can change >100 ppb in <3 h, occur in the presence of synoptic disturbances. Under fair weather conditions, local- to regional-scale transport processes are found to be more important drivers of the diurnal CO variability. On fair weather days with northwesterly winds, boundary layer dilution causes a daytime CO decrease, resembling the variability observed atop tall towers in flat terrain. Fair weather days with a wind shift from the northwest to the south are characterised by an afternoon CO increase and resemble the variability observed at mountaintops influenced by the vertical transport of polluted air from adjacent valleys.

  18. The efficiency of different types of wood charcoal on increasing carbon content on surfaces of low carbon steel in the pack carburizing process

    Directory of Open Access Journals (Sweden)

    Narongsak Thammachot

    2014-09-01

    Full Text Available The purpose of this research is to compare the efficiency of five types of wood charcoal, eucalyptus, coconut shell, tamarind, bamboo and cassava root in increasing carbon content on surfaces of low carbon steel by the pack carburizing process. The experiment for pack carburized low carbon steel (grade AISI 1020 was conducted by using the different wood charcoals as carburizers, mixed with 10% limestone (by weight as the energizer. The carburizing temperature of 950°C, and carburizing times of 2, 4 and 6 hours were used in the experiment. After grinding, the specimens in each case were checked for carbon content by optical emission spectroscopy. Micro-Vickers hardness testing and microstructure inspections were carried out. The results of the experiment showed that the efficiency of eucalyptus charcoal as the carburizer (for increasing carbon content on surfaces of low carbon steel was higher than that of tamarind, cassava root, coconut shell and bamboo charcoals. The averages for carbon content were: 1.16, 1.06, 0.97, 0.83 and 0.77% respectively.

  19. Most probable mixing state of aerosols in Delhi NCR, northern India

    Science.gov (United States)

    Srivastava, Parul; Dey, Sagnik; Srivastava, Atul Kumar; Singh, Sachchidanand; Tiwari, Suresh

    2018-02-01

    Unknown mixing state is one of the major sources of uncertainty in estimating aerosol direct radiative forcing (DRF). Aerosol DRF in India is usually reported for external mixing and any deviation from this would lead to high bias and error. Limited information on aerosol composition hinders in resolving this issue in India. Here we use two years of aerosol chemical composition data measured at megacity Delhi to examine the most probable aerosol mixing state by comparing the simulated clear-sky downward surface flux with the measured flux. We consider external, internal, and four combinations of core-shell (black carbon, BC over dust; water-soluble, WS over dust; WS over water-insoluble, WINS and BC over WINS) mixing. Our analysis reveals that choice of external mixing (usually considered in satellite retrievals and climate models) seems reasonable in Delhi only in the pre-monsoon (Mar-Jun) season. During the winter (Dec-Feb) and monsoon (Jul-Sep) seasons, 'WS coating over dust' externally mixed with BC and WINS appears to be the most probable mixing state; while 'WS coating over WINS' externally mixed with BC and dust seems to be the most probable mixing state in the post-monsoon (Oct-Nov) season. Mean seasonal TOA (surface) aerosol DRF for the most probable mixing states are 4.4 ± 3.9 (- 25.9 ± 3.9), - 16.3 ± 5.7 (- 42.4 ± 10.5), 13.6 ± 11.4 (- 76.6 ± 16.6) and - 5.4 ± 7.7 (- 80.0 ± 7.2) W m- 2 respectively in the pre-monsoon, monsoon, post-monsoon and winter seasons. Our results highlight the importance of realistic mixing state treatment in estimating aerosol DRF to aid in policy making to combat climate change.

  20. Colloid dynamics and transport of major elements through a boreal river - brackish bay mixing zone

    DEFF Research Database (Denmark)

    Gustafsson, Ö.; Widerlund, A.; Andersson, P.

    2000-01-01

    km in the spring.. During the dynamic springflood conditions studied, small 238U–234Th disequilibria, low sediment trap fluxes, laboratory mixing experiments, as well as results from an independent two-box, two-dimensional mixing model combine to suggest that no significant removal of Fe, Si......A range of biogeochemical methodologies were applied to investigate how aggregation processes affected the phase distribution and mixing of Fe, Si, and organic carbon between the Kalix River and the Bothnic Bay, northernmost Baltic Sea salinityF3; the low-salinity zone LSZ. was stretching over 60...... similar to that of neighboring Russian Arctic rivers, is hypothesized to result from a comparatively high organic-to-detrital matter characteristic of the aggregates. While first principles would indeed suggest that decreasing electrostatic repulsion during mixing lead to aggregation, a low specific...

  1. Carbon sequestration and climate policy: elements of economic analysis. CGDD-TSE partnership

    International Nuclear Information System (INIS)

    Dubreu, Nathalie; Hardelin, Julien; Gilles Lafforgue

    2012-05-01

    In September 2011 the General Commission for Sustainable Development and Toulouse School of Economics jointly organized a conference on 'Carbon capture and storage (CCS) and climate policies: an economic analysis'. This paper presents an overview of the main results of the conference concerning the optimal energy mix and carbon emission path in the presence of CCS, the superiority of a policy mix combining an environmental tax with R and D subsidies, as well as the inter-generational equity-efficiency trade-off. It is based on presentations by Gilles Lafforgue, Andre Grimaud and Michel Moreaux, researchers from the Toulouse School of Economics. This overview confirms that a climate policy is more effective if it combines several instruments (tax and subsidies) and if it is quickly implemented. (authors)

  2. The oceanic response to carbon emissions over the next century: investigation using three ocean carbon cycle models

    International Nuclear Information System (INIS)

    Chuck, A.; Tyrrell, T.; Holligan, P.M.; Totterdell, I.J.

    2005-01-01

    A recent study of coupled atmospheric carbon dioxide and the biosphere found alarming sensitivity of next-century atmospheric pCO 2 (and hence planetary temperature) to uncertainties in terrestrial processes. Here we investigate whether there is similar sensitivity associated with uncertainties in the behaviour of the ocean carbon cycle. We investigate this important question using three models of the ocean carbon cycle of varying complexity: (1) a new three-box oceanic carbon cycle model; (2) the HILDA multibox model with high vertical resolution at low latitudes; (3) the Hadley Centre ocean general circulation model (HadOCC). These models were used in combination to assess the quantitative significance (to year 2100 pCO 2 ) of potential changes to the ocean stimulated by global warming and other anthropogenic activities over the period 2000-2100. It was found that an increase in sea surface temperature and a decrease in the mixing rate due to stratification give rise to the greatest relative changes in pCO 2 , both being positive feedbacks. We failed to find any comparable large sensitivity due to the ocean

  3. Electron spectroscopy of rubber and resin-based composites containing 2D carbon

    International Nuclear Information System (INIS)

    Kaciulis, S.; Mezzi, A.; Balijepalli, S.K.; Lavorgna, M.; Xia, H.S.

    2015-01-01

    Composite materials with 2D carbon (graphene and/or single wall carbon nanotubes) are very promising due to their extraordinary electrical and mechanical properties. Graphene and natural rubber composites, which may be used for the gaskets or sealants, were prepared by ultrasonically assisted latex-mixing exfoliation and in-situ reduction process, with two vulcanization approaches: roll-mixing and hot-pressing. Also the resin-based composites, filled with micro-particles of Ag and graphene or carbon nanotubes, have been studied. The standards for the compositional characterization of these materials still are not established. In addition to the mostly used techniques, such as Raman spectroscopy and electron microscopy, also Auger electron spectroscopy can be employed for the identification of graphene. In this study, the shape of C KVV peak, excited by electron beam and X-ray photons, has been investigated in different composite materials containing graphene and carbon nanotubes. A spectroscopic method for 2D carbon recognition, based on the D x parameter which is determined from C KVV signal excited by X-ray photons, was proposed and verified. Even a small content of graphene in different types of composites was sufficient for this recognition due to the dominating presence of graphene on the surface of composites. - Highlights: • Chemical composition of the rubber composites was determined by XPS. • Auger spectrum of carbon was used for graphene identification in composites. • Small content of graphene was sufficient for its recognition from the D parameter

  4. Electron spectroscopy of rubber and resin-based composites containing 2D carbon

    Energy Technology Data Exchange (ETDEWEB)

    Kaciulis, S., E-mail: saulius.kaciulis@ismn.cnr.it [Institute for the Study of Nanostructured Materials, ISMN-CNR, P.O. Box 10, Monterotondo Stazione, 00015 Roma (Italy); Mezzi, A.; Balijepalli, S.K. [Institute for the Study of Nanostructured Materials, ISMN-CNR, P.O. Box 10, Monterotondo Stazione, 00015 Roma (Italy); Lavorgna, M. [Institute of Polymers, Composites and Biomaterials, IPCB-CNR, P.le Fermi, 80055 Napoli (Italy); Xia, H.S. [State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065 Sichuan (China)

    2015-04-30

    Composite materials with 2D carbon (graphene and/or single wall carbon nanotubes) are very promising due to their extraordinary electrical and mechanical properties. Graphene and natural rubber composites, which may be used for the gaskets or sealants, were prepared by ultrasonically assisted latex-mixing exfoliation and in-situ reduction process, with two vulcanization approaches: roll-mixing and hot-pressing. Also the resin-based composites, filled with micro-particles of Ag and graphene or carbon nanotubes, have been studied. The standards for the compositional characterization of these materials still are not established. In addition to the mostly used techniques, such as Raman spectroscopy and electron microscopy, also Auger electron spectroscopy can be employed for the identification of graphene. In this study, the shape of C KVV peak, excited by electron beam and X-ray photons, has been investigated in different composite materials containing graphene and carbon nanotubes. A spectroscopic method for 2D carbon recognition, based on the D{sub x} parameter which is determined from C KVV signal excited by X-ray photons, was proposed and verified. Even a small content of graphene in different types of composites was sufficient for this recognition due to the dominating presence of graphene on the surface of composites. - Highlights: • Chemical composition of the rubber composites was determined by XPS. • Auger spectrum of carbon was used for graphene identification in composites. • Small content of graphene was sufficient for its recognition from the D parameter.

  5. Use for refuse of shale carbonization

    Energy Technology Data Exchange (ETDEWEB)

    1917-09-25

    A process is disclosed for using the refuse from the carbonization of bituminous shales in the preparation of light building material, characterized in that the pulverized material is mixed wet with a light filler, formed in a mold, and burned with or without the addition of clay or with the addition of binding and preserving material, preparing the mold from the pulverized material in the cold.

  6. CONCRETE MIX DESIGN FOR STRUCTURES SUBJECTED TO EXPOSURE CLASS XC1 DEPENDING ON CONCRETE COVER

    Directory of Open Access Journals (Sweden)

    O. Yu. Cherniakevich

    2016-01-01

    Full Text Available The reinforced steel corrosion which is the most important problem of reinforced concrete structures durability is generally stipulated for carbonization of concrete surrounding it. Concrete cover calculation at the design stage is predicated one because of the differences in manufacturing conditions and use of constructions. The applying of the probabilistic approaches to the carbonation process modeling allows to get predicated grade of the depth of carbonization of concrete and, thus, to settle minimum concrete cover thickness for a given projected service life of a construction. The procedures for concrete mix design for different strength classes of concrete are described in the article. Current recommendations on assignment of concrete strength class as well as concrete cover are presented. The European Standard EN 206:2013 defines the content requirements for the concrete structures operated in the exposure class XC1, including the minimum values of water-cement ratio, minimum cement content, and minimum strength class of concrete. Since the standard does not include any basis or explanations of the requirements, we made an effort to develop a scientific justification for the mentioned requirements. We developed the probabilistic models for the process of carbonation of concrete based on the concrete mix which was designed using the software VTK-Korroziya. The reinforced concrete structures with concrete cover 20–35 mm operated in the most unfavorable conditions within the exposure class XC1 were analyzed. The corresponding probabilistic calculations of the depth of carbonated concrete are described in the article. 

  7. Dynamics of carbon abatement in the Second Generation Model

    International Nuclear Information System (INIS)

    Sands, Ronald D.

    2004-01-01

    The Second Generation Model (SGM) is a collection of computable-general-equilibrium models developed for analysis of policies to reduce greenhouse gas emissions. Behavior of the Second Generation Model, with respect to changes in carbon prices, can be summarized using marginal abatement cost curves. Marginal abatement costs vary over time, as capital stocks adjust to a new set of prices, and across countries, depending in part on the mix of fuels in the existing energy system. This paper documents the production structure in SGM, marginal abatement cost curves derived from SGM with constant-carbon-price experiments, an application to several Energy Modeling Forum scenarios, and a methodology for including carbon capture and disposal in SGM

  8. Effect of carbon dioxide and bicarbonate as inorganic carbon sources on growth and adaptation of autohydrogenotrophic denitrifying bacteria

    International Nuclear Information System (INIS)

    Ghafari, Shahin; Hasan, Masitah; Aroua, Mohamed Kheireddine

    2009-01-01

    Acclimation of autohydrogenotrophic denitrifying bacteria using inorganic carbon source (CO 2 and bicarbonate) and hydrogen gas as electron donor was performed in this study. In this regard, activated sludge was used as the seed source and sequencing batch reactor (SBR) technique was applied for accomplishing the acclimatization. Three distinct strategies in feeding of carbon sources were applied: (I) continuous sparging of CO 2 , (II) bicarbonate plus continuous sparging of CO 2 , and (III) only bicarbonate. The pH-reducing nature of CO 2 showed an unfavorable impact on denitrification rate; however bicarbonate resulted in a buffered environment in the mixed liquor and provided a suitable mean to maintain the pH in the desirable range of 7-8.2. As a result, bicarbonate as the only carbon source showed a faster adaptation, while carbon dioxide as the only carbon source as well as a complementary carbon source added to bicarbonate resulted in longer acclimation period. Adapted hydrogenotrophic denitrifying bacteria, using bicarbonate and hydrogen gas in the aforementioned pH range, caused denitrification at a rate of 13.33 mg NO 3 - -N/g MLVSS/h for degrading 20 and 30 mg NO 3 - -N/L and 9.09 mg NO 3 - -N/g MLVSS/h for degrading 50 mg NO 3 - -N/L

  9. Expedited demonstration of molten salt mixed waste treatment technology. Final report

    International Nuclear Information System (INIS)

    1995-01-01

    This final report discusses the molten salt mixed waste project in terms of the various subtasks established. Subtask 1: Carbon monoxide emissions; Establish a salt recycle schedule and/or a strategy for off-gas control for MWMF that keeps carbon monoxide emission below 100 ppm on an hourly averaged basis. Subtask 2: Salt melt viscosity; Experiments are conducted to determine salt viscosity as a function of ash composition, ash concentration, temperature, and time. Subtask 3: Determine that the amount of sodium carbonate entrained in the off-gas is minimal, and that any deposited salt can easily be removed form the piping using a soot blower or other means. Subtask 4: The provision of at least one final waste form that meets the waste acceptance criteria of a landfill that will take the waste. This report discusses the progress made in each of these areas

  10. Bonded Joints with “Nano-Stitches”: Effect of Carbon Nanotubes on Load Capacity and Failure Modes

    Directory of Open Access Journals (Sweden)

    Henrique N. P. Oliva

    Full Text Available Abstract Carbon nanotubes were employed as adhesive reinforcement/nano-stitches to aluminum bonded joints. The CNT addition to an epoxy adhesive not only lead to an increase on load capacity but it is also the most probable cause of the mixed failure mode (adhesive/cohesive. The damage evolution was described as the stiffness decrease and the failure mixed modes were related to the load capacity. Although the presence of CNT cluster were observed, in small concentrations (< 1.0 wt. %, these clusters acted as crack stoppers and lead to an increase on lap joint shear strength. The addition of 2.0 wt. % carbon nanotubes lead to an increase on load capacity of approximately 116.2 % when the results were compared against the single lap joints without carbon nanotubes.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

  12. Different rays of sunlight: Understanding information disclosure and carbon transparency

    International Nuclear Information System (INIS)

    Matisoff, Daniel C.

    2013-01-01

    This study assesses the effectiveness of two types information disclosure programs – state-based mandatory carbon reporting programs and the voluntary Carbon Disclosure Project, which uses investor pressure to push firms to disclose carbon emissions and carbon management strategies. I match firms in each program to control groups of firms that have not participated in each program. Using panel data methods and a difference in differences specification, I measure the impact of each program on plant-level carbon emissions, plant-level carbon intensity, and plant level output. I find that neither program has generated an impact on plant-level carbon emissions, emissions intensity, or output. Placing this study in contrast with others that demonstrate improvements from mandatory information disclosure, these results suggest that how information is reported to stakeholders has important implications for program effectiveness. - Highlights: ► This article evaluates the Carbon Disclosure Project and state carbon reporting requirements. ► Evaluation is conducted with propensity score matching and difference-in-differences. ► State Disclosure Programs fail to lead power plants to reduce carbon dioxide emissions. ► The Carbon Disclosure Project leads to decreases in carbon emissions and electricity output. ► Information disclosure and transparency may be important part of policy mix but have limitations

  13. Contribution of deep sourced carbon from hydrocarbon seeps to sedimentary organic carbon: Evidence from Δ14C and δ13C isotopes

    Science.gov (United States)

    Feng, D.; Peckmann, J.; Peng, Y.; Liang, Q.; Roberts, H. H.; Chen, D.

    2017-12-01

    Sulfate-driven anaerobic oxidation of methane (AOM) limits the release of methane from marine sediments and promotes the formation of carbonates close to the seafloor along continental margins. It has been established that hydrocarbon seeps are a source of dissolved inorganic and organic carbon to marine environments. However, questions remain about the contribution of deep sourced carbon from hydrocarbon seeps to the sedimentary organic carbon pool. For a number of hydrocarbon seeps from the South China Sea and the Gulf of Mexico, the portion of modern carbon was determined based on natural radiocarbon abundances (Δ14C) and stable carbon isotope (δ13Corganic carbon) compositions of the non-carbonate fractions extracted from authigenic carbonates. Samples from both areas show a mixing trend between ideal planktonic organic carbon (δ13C = -22‰ VPDB and 90% modern carbon) and the ambient methane. The δ13Corganic carbon values of non-carbonate fractions from three ancient seep deposits (northern Italy, Miocene; western Washington State, USA, Eocene to Oligocene) confirm that the proxy can be used to constrain the record of sulfate-driven AOM through most of Earth history by measuring the δ13C values of organic carbon. This study reveals the potential of using δ13C values of organic carbon to discern seep and non-seep environments. This new approach is particularly promising when authigenic carbonate is not present in ancient sedimentary environments. Acknowledgments: The authors thank BOEM and NOAA for their years' support of the deep-sea dives. Funding was provided by the NSF of China (Grants: 41422602 and 41373085).

  14. Sustainable Low Carbon Transport Scenarios for India

    DEFF Research Database (Denmark)

    Shukla, P.R.; Dhar, Subash; Mittal, Shivika

    2014-01-01

    and local air quality that can be accrued by mainstreaming climate change polices into national sustainable development goals and sectoral plans are also estimated. There is no silver bullet that would enable the transition towards low carbon transport. An optimal mix of policies that includes fuel economy...... standards, modal shifts and cleaner energy supply is required to align climate and sustainable development goals in the long-term....... are delineated that would facilitate the sustainable low carbon transformation of India’s transport sector. The long term energy and emission trajectory of India’s transport sector is assessed under alternate scenarios using the integrated assessment modelling framework. Co-benefits like energy security...

  15. Estimating the Biodegradation Kinetics by Mixed Culture Degrading Pyrene (Pyr

    Directory of Open Access Journals (Sweden)

    B. S. U. Ibn Abubakar

    2017-02-01

    Full Text Available Biodegradation and kinetics of Pyrene (Pyr degradation by a mixed culture previously isolated from hydrocarbon-polluted soil were conducted. Preliminary investigation on environmental factors affecting the degradation of Pyr such as temperature, pH and concentrations of Pyr was performed. These factors were optimised and established in aqueous experiments. In order to develop kinetics of Pyr degradation, an optimum temperature of 30oC and pH of 7.0 was used. Biodegradation kinetics was carried out, at first, using higher concentration between (100-700 ppm as sole source of carbon in mineral salt medium (MSM supplemented with 0.1% yeast extract. The result indicated that a range of concentration between (100-700 ppm inhibits the performance of the mixed culture. A concentration range between (10-100 ppm did not inhibit the growth of the mixed culture. A First-order rate constant, k was higher (0.0487 mg/lh with a substrate concentration of 20 ppm than other concentrations. The average degradation rate constant is 0.0029 mg/Lh for all the concentrations tested. This indicated that the mixed culture could degrade over 0.0696 ppm of Pyr per day. It also confirmed that kinetics of microbial degradation was partially fitted into Monod model. The data can be used to estimate biodegradation of Pyr by a mixed culture and preliminarily estimation of degradation rates.

  16. Mixed Uranium/Refractory Metal Carbide Fuels for High Performance Nuclear Reactors

    International Nuclear Information System (INIS)

    Knight, Travis; Anghaie, Samim

    2002-01-01

    Single phase, solid-solution mixed uranium/refractory metal carbides have been proposed as an advanced nuclear fuel for advanced, high-performance reactors. Earlier studies of mixed carbides focused on uranium and either thorium or plutonium as a fuel for fast breeder reactors enabling shorter doubling owing to the greater fissile atom density. However, the mixed uranium/refractory carbides such as (U, Zr, Nb)C have a lower uranium densities but hold significant promise because of their ultra-high melting points (typically greater than 3700 K), improved material compatibility, and high thermal conductivity approaching that of the metal. Various compositions of (U, Zr, Nb)C were processed with 5% and 10% metal mole fraction of uranium. Stoichiometric samples were processed from the constituent carbide powders, while hypo-stoichiometric samples with carbon-to-metal (C/M) ratios of 0.92 were processed from uranium hydride, graphite, and constituent refractory carbide powders. Processing techniques of cold uniaxial pressing, dynamic magnetic compaction, sintering, and hot pressing were investigated to optimize the processing parameters necessary to produce high density (low porosity), single phase, solid-solution mixed carbide nuclear fuels for testing. This investigation was undertaken to evaluate and characterize the performance of these mixed uranium/refractory metal carbides for high performance, ultra-safe nuclear reactor applications. (authors)

  17. Biomass and lipid production of Chlorella protothecoides under heterotrophic cultivation on a mixed waste substrate of brewer fermentation and crude glycerol.

    Science.gov (United States)

    Feng, Xiaoyu; Walker, Terry H; Bridges, William C; Thornton, Charles; Gopalakrishnan, Karthik

    2014-08-01

    Biomass and lipid accumulation of heterotrophic microalgae Chlorella protothecoides by supplying mixed waste substrate of brewer fermentation and crude glycerol were investigated. The biomass concentrations of the old and the new C. protothecoides strains on day 6 reached 14.07 and 12.73 g/L, respectively, which were comparable to those in basal medium with supplement of glucose and yeast extract (BM-GY) (14.47 g/L for old strains and 11.43 g/L for new strains) (P>0.05). Approximately 81.5% of total organic carbon and 65.1% of total nitrogen in the mixed waste were effectively removed. The accumulated lipid productivities of the old and the new C. protothecoides strains in BM-GY were 2.07 and 1.61 g/L/day, respectively, whereas in the mixed waste, lipid productivities could reach 2.12 and 1.81 g/L/day, respectively. Our result highlights a new approach of mixing carbon-rich and nitrogen-rich wastes as economical and practical alternative substrates for biofuel production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Carbon isotope ratios of organic matter in Bering Sea settling particles. Extremely high remineralization of organic carbon derived from diatoms

    International Nuclear Information System (INIS)

    Yasuda, Saki; Akagi, Tasuku; Naraoka, Hiroshi; Kitajima, Fumio; Takahashi, Kozo

    2016-01-01

    The carbon isotope ratios of organic carbon in settling particles collected in the highly-diatom-productive Bering Sea were determined. Wet decomposition was employed to oxidize relatively fresh organic matter. The amount of unoxidised organic carbon in the residue following wet decomposition was negligible. The δ 13 C of organic carbon in the settling particles showed a clear relationship against SiO 2 /CaCO 3 ratio of settling particles: approximately -26‰ and -19‰ at lower and higher SiO 2 /CaCO 3 ratios, respectively. The δ 13 C values were largely interpreted in terms of mixing of two major plankton sources. Both δ 13 C and compositional data can be explained consistently only by assuming that more than 98% of diatomaceous organic matter decays and that organic matter derived from carbonate-shelled plankton may remain much less remineralized. A greater amount of diatom-derived organic matter is discovered to be trapped with the increase of SiO 2 /CaCO 3 ratio of the settling particles. The ratio of organic carbon to inorganic carbon, known as the rain ratio, therefore, tends to increase proportionally with the SiO 2 /CaCO 3 ratio under an extremely diatom-productive condition. (author)

  19. A time-series analysis of energy-related carbon emissions in Korea

    International Nuclear Information System (INIS)

    Ki-Hong Choi; Ang, B.W.

    2001-01-01

    Energy-related carbon emissions and their relationships with energy consumption and GNP in Korea are studied from 1961 to 1998. The ratio of carbon emissions to GNP is expressed as the product of the aggregate carbon factor and the energy intensity. Changes in the aggregate carbon factor are decomposed into the impacts associated with the fuel carbon factor and the fuel mix, using the Divisia index approach. The analysis is carried out using two sets of data, with and without wood consumption as an energy source, and very different results are obtained. This shows that carbon emission studies for developing countries based on commercial energy consumption only may have to be interpreted with caution. Our analysis also reveals that the impact of the energy intensity on carbon emissions is greater than that of the aggregate carbon factor. This finding supports the assertion made in earlier studies that the energy intensity is a more meaningful indicator than the aggregate carbon factor in the study of climate change resulting from energy-related emissions. (author)

  20. Analysis of carbon dioxide, water vapour and energy fluxes over an ...

    Indian Academy of Sciences (India)

    over an Indian teak mixed deciduous forest for winter and summer ... Anderson and Verma 1986) and in natural ecosys- tems (Wesely ... ject of the 'National Carbon Project – NCP' – ..... productivity of planet earth: Biological determinants and.

  1. PREPARATION OF WC-Co POWDER BY DIRECT REDUCTION AND CARBONIZATION

    Institute of Scientific and Technical Information of China (English)

    Zhonglai Yi; Gangqin Shao; Xinglong Duan; Peng Sun; Xiaoliang Shi; Zhen Xiong; Jingkun Guo

    2005-01-01

    A new approach to produce superfine WC-Co powder by direct reduction and carbonization is proposed.Water-soluble salts containing W and Co were used as raw materials. Tungsten and cobalt oxide powder (CoWO4/WO3)was first formed by a spray-pyrolysis technique, which was then mixed with carbon black and converted to WC-Co composite powder at 950℃ for 4 h in N2 atmosphere. The resulting powder has a particle size of 100-300 nm.

  2. Preliminary Study of Fermented Tapioca for Synthesis of Carbon Nano tubes

    International Nuclear Information System (INIS)

    Nurulhuda Ismail; Ying, P.Y.

    2011-01-01

    Carbon nano tubes had been produced by various precursor such as gas (methane, carbon dioxide), oil (camphor oil, olive oil, and cooking oil) and alcohol. Different methods used for carbon nano tubes synthesis like arc discharge method, laser ablation method and chemical vapour deposition method. In this experiment, thermal chemical vapour deposition method was selected for carbon nano tubes synthesis. Starting material of fermented tapioca was used as carbon source for the process. Argon gas flow were controlled at around 10-15 bubbles per minute and deposition time around 20 to 30 minute. Others parameters such as temperature of furnace 1 and 2, amount of inoculum and catalyst have been studied. The asThermogravimetri (TGA) was used to determine the volatile temperature of the mixing catalyst and fermented tapioca extract. The grown carbon nano tubes morphology was characterized through Raman spectroscopy, scanning and Field Emission Scanning Electron Microscopy (FESEM) techniques. The surface morphology and uniformity of carbon nano tubes are reliant to parameters used. (author)

  3. Determination of carbon-14 environmental samples by mixing 14CO2 with a liquid scintillator

    International Nuclear Information System (INIS)

    Garcia Sanz, M.R.; Gomez, V.; Heras, M.C.; Beltran, M.A.

    1990-01-01

    A method for the determination of Carbon-14 ( 14 CO 2 ) in environmental samples has been developed. The method use the direct absorption of the carbon dioxide into Carbosorb, followed with incorporation of the mixture (Carbosorb-CO 2 ) to the liquid scintillator. The results obtained to apply this method and the benzene synthesis, usual in our laboratory, are discused and compared. The method of collection of atmospheric samples is also described. (Author)

  4. Effect of Novel Quercetin Titanium Dioxide-Decorated Multi-Walled Carbon Nanotubes Nanocomposite on Bacillus subtilis Biofilm Development

    DEFF Research Database (Denmark)

    Raie, Diana S; Mhatre, Eisha; El-Desouki, Doaa S

    2018-01-01

    The present work was targeted to design a surface against cell seeding and adhering of bacteria, Bacillus subtilis. A multi-walled carbon nanotube/titanium dioxide nano-power was produced via simple mixing of carbon nanotube and titanium dioxide nanoparticles during the sol-gel process followed...

  5. Preparation and thermal properties characterization of carbonate salt/carbon nanomaterial composite phase change material

    International Nuclear Information System (INIS)

    Tao, Y.B.; Lin, C.H.; He, Y.L.

    2015-01-01

    Highlights: • Nanocomposite phase change materials were prepared and characterized. • Larger specific surface area is more efficient to enhance specific heat. • Columnar structure is more efficient to enhance thermal conductivity. • Thermal conductivity enhancement is the key. • Single walled carbon nanotube is the optimal nanomaterial additive. - Abstract: To enhance the performance of high temperature salt phase change material, four kinds of carbon nanomaterials with different microstructures were mixed into binary carbonate eutectic salts to prepare carbonate salt/nanomaterial composite phase change material. The microstructures of the nanomaterial and composite phase change material were characterized by scanning electron microscope. The thermal properties such as melting point, melting enthalpy, specific heat, thermal conductivity and total thermal energy storage capacity were characterized. The results show that the nanomaterial microstructure has great effects on composite phase change material thermal properties. The sheet structure Graphene is the best additive to enhance specific heat, which could be enhanced up to 18.57%. The single walled carbon nanotube with columnar structure is the best additive to enhance thermal conductivity, which could be enhanced up to 56.98%. Melting point increases but melting enthalpy decreases with nanomaterial specific surface area increase. Although the additives decrease the melting enthalpy of composite phase change material, they also enhance the specific heat. As a combined result, the additives have little effects on thermal energy storage capacity. So, for phase change material performance enhancement, more emphasis should be placed on thermal conductivity enhancement and single walled carbon nanotube is the optimal nanomaterial additive

  6. 11 things a geologist thinks an engineer should know about carbonate beaches

    Science.gov (United States)

    Halley, Robert B.; Magoon, Orville T.; Robbins, Lisa L.; Ewing, Lesley

    2002-01-01

    This is a review of the geological aspects of carbonate beaches that a geologist thinks may be useful for an engineer. Classical geologic problems of carbonate beaches, for example how ancient examples are recognized in rock sequences, are of little interest to engineers. Geologists not involved in engineering problems may find it difficult to know what an engineer should understand about carbonate beaches. Nevertheless, there are at least eleven topics that are potentially very useful for engineers to keep in mind. These eleven are chosen with as much thought going into what has been omitted as has been given to the eleven included topics. Some qualifications are in order: First, this paper does not discuss certain kinds of carbonate shorelines that are beyond the scope of engineering issues. For example, this review does not discuss very high-energy carbonate boulder beaches. These beaches are comprised of pieces of carbonate material ganging in size from ten centimeters to meters. Typically, these are high-energy storm deposits formed from pieces of either eroded carbonate rock or other large carbonate pieces such as pieces of large corals. This paper focuses on sand-sized (0.0625–2.0 mm) coastal carbonate deposits. Second, offshore beaches will not be discussed. There are many carbonate beaches that form on banks or shoals exposed at low tide, but our discussion is confined to what most people think of when they go to some tropical island and/or resort and walk out to lay on the beach. Third, this paper does not consider mixed carbonate/quartz sand beaches. While mixed beaches are common, only the end member of purely carbonate sand beaches is considered. Fourth, there will be no order of preference of the eleven topics. And lastly, these eleven topics are not consensus items. These are simply one geologist s thoughts about the aspects of carbonate beaches that would be useful for engineering colleagues to keep in mind. Where possible, general reference is

  7. Black carbon in aerosol during BIBLE B

    Science.gov (United States)

    Liley, J. Ben; Baumgardner, D.; Kondo, Y.; Kita, K.; Blake, D. R.; Koike, M.; Machida, T.; Takegawa, N.; Kawakami, S.; Shirai, T.; Ogawa, T.

    2003-02-01

    The Biomass Burning and Lightning Experiment (BIBLE) A and B campaigns over the tropical western Pacific during springtime deployed a Gulfstream-II aircraft with systems to measure ozone and numerous precursor species. Aerosol measuring systems included a MASP optical particle counter, a condensation nucleus (CN) counter, and an absorption spectrometer for black carbon. Aerosol volume was very low in the middle and upper troposphere during both campaigns, and during BIBLE A, there was little aerosol enhancement in the boundary layer away from urban areas. In BIBLE B, there was marked aerosol enhancement in the lowest 3 km of the atmosphere. Mixing ratios of CN in cloud-free conditions in the upper troposphere were in general higher than in the boundary layer, indicating new particle formation from gaseous precursors. High concentrations of black carbon were observed during BIBLE B, with mass loadings up to 40 μg m-3 representing as much as one quarter of total aerosol mass. Strong correlations with hydrocarbon enhancement allow the determination of a black carbon emission ratio for the fires at that time. Expressed as elemental carbon, it is about 0.5% of carbon dioxide and 6% of carbon monoxide emissions from the same fires, comparable to methane production, and greater than that of other hydrocarbons.

  8. Baselines for carbon emissions in the Indian and Chinese power sectors: Implications for international carbon trading

    International Nuclear Information System (INIS)

    Zhang Chi; Shukla, P.R.; Victor, David G.; Heller, Thomas C.; Biswas, Debashish; Nag, Tirthankar

    2006-01-01

    The study examines the dynamics of carbon emissions baselines of electricity generation in Indian states and Chinese provinces in the backdrop of ongoing electricity sector reforms in these countries. Two Indian states-Gujarat and Andhra Pradesh, and three Chinese provinces-Guangdong, Liaoning and Hubei have been chosen for detailed analysis to bring out regional variations that are not captured in aggregate country studies. The study finds that fuel mix is the main driver behind the trends exhibited by the carbon baselines in these five cases. The cases confirm that opportunities exist in the Indian and Chinese electricity sectors to lower carbon intensity mainly in the substitution of other fuels for coal and, to a lesser extent, adoption of more efficient and advanced coal-fired generation technology. Overall, the findings suggest that the electricity sectors in India and China are becoming friendlier to the global environment. Disaggregated analysis, detailed and careful industry analysis is essential to establishing a power sector carbon emissions baseline as a reference for CDM crediting. However, considering all the difficulties associated with the baseline issue, our case studies demonstrate that there is merit in examining alternate approaches that rely on more aggregated baselines

  9. Stirring Up the Biological Pump: Vertical Mixing and Carbon Export in the Southern Ocean

    Science.gov (United States)

    Stukel, Michael R.; Ducklow, Hugh W.

    2017-09-01

    The biological carbon pump (BCP) transports organic carbon from the surface to the ocean's interior via sinking particles, vertically migrating organisms, and passive transport of organic matter by advection and diffusion. While many studies have quantified sinking particles, the magnitude of passive transport remains poorly constrained. In the Southern Ocean weak thermal stratification, strong vertical gradients in particulate organic matter, and weak vertical nitrate gradients suggest that passive transport from the euphotic zone may be particularly important. We compile data from seasonal time series at a coastal site near Palmer Station, annual regional cruises in the Western Antarctic Peninsula (WAP), cruises throughout the broader Southern Ocean, and SOCCOM (Southern Ocean Carbon and Climate Observations and Modeling) autonomous profiling floats to estimate spatial and temporal patterns in vertical gradients of nitrate, particulate nitrogen (PN), and dissolved organic carbon. Under a steady state approximation, the ratio of ∂PN/∂z to ∂NO3-/∂z suggests that passive transport of PN may be responsible for removing 46% (37%-58%) of the nitrate introduced into the surface ocean of the WAP (with dissolved organic matter contributing an additional 3-6%) and for 23% (19%-28%) of the BCP in the broader Southern Ocean. A simple model parameterized with in situ nitrate, PN, and primary production data suggested that passive transport was responsible for 54% of the magnitude of the BCP in the WAP. Our results highlight the potential importance of passive transport (by advection and diffusion) of organic matter in the Southern Ocean but should only be considered indicative of high passive transport (rather than conclusive evidence) due to our steady state assumptions.

  10. A Three End-Member Mixing Model Based on Isotopic Composition and Elemental Ratio

    Directory of Open Access Journals (Sweden)

    Kon-Kee Liu Shuh-Ji Kao

    2007-01-01

    Full Text Available A three end-member mixing model based on nitrogen isotopic composition and organic carbon to nitrogen ratio of suspended particulate matter in an aquatic environment has been developed. Mathematical expressions have been derived for the calculation of the fractions of nitrogen or organic carbon originating from three different sources of distinct isotopic and elemental compositions. The model was successfully applied to determine the contributions from anthropogenic wastes, soils and bedrock-derived sediments to particulate nitrogen and particulate organic carbon in the Danshuei River during the flood caused by Typhoon Bilis in August 2000. The model solutions have been expressed in a general form that allows applications to mixtures with other types of isotopic compositions and elemental ratios or in forms other than suspended particulate matter.

  11. DNA-mediated self-assembly of carbon nanotubes on gold

    International Nuclear Information System (INIS)

    Sanchez-Pomales, Germarie; Rivera-Velez, Nelson E; Cabrera, Carlos R

    2007-01-01

    This report presents the use of disulfide-modified single-stranded DNA (ssDNA) to form DNA self-assembled monolayers (SAMs) and mixed DNA-carbon nanotube (CNT) hybrids SAMs on gold substrates. Mixed DNA-CNT SAMs are composed of DNA, mercaptohexanol (MCH) and DNA-CNT aggregates. Both, DNA-CNT and DNA areas of the mixed SAMs were analyzed and compared to traditional DNA SAMs. The results suggest the formation of a more compact and densely packed monolayer of DNA-CNT in comparison with DNA. The use of DNA-CNT hybrids to form SAMs on gold substrates might represent a new approach to improve the immobilization of DNA strands on gold, and might therefore help with the development of enhanced DNA sensors

  12. SISGR - Hydrogen Caged in Carbon-Exploration of Novel Carbon-Hydrogen Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Lueking, Angela [Pennsylvania State Univ., State College, PA (United States); Badding, John [Pennsylvania State Univ., State College, PA (United States); Crespi, Vinent [Pennsylvania State Univ., State College, PA (United States)

    2015-12-01

    Hydrogen trapped in a carbon cage, captured through repulsive interactions, is a novel concept in hydrogen storage. Trapping hydrogen via repulsive interactions borrows an idea from macroscale hydrogen storage (i.e. compressed gas storage tanks) and reapplies these concepts on the nanoscale in specially designed molecular containers. Under extreme conditions of pressure, hydrogen solubility in carbon materials is expected to increase and carbon is expected to restructure to minimize volume via a mixed sp2/sp3 hydrogenated state. Thermodynamics dictate that pre-formed C-H structures will rearrange with increased pressure, yet the final carbon-hydrogen interactions may be dependent upon the mechanism by which hydrogen is introduced. Gas “trapping” is meant to denote gas present in a solid in a high density, adsorbed-like state, when the external pressure is much less than that necessary to provide a comparable fluid density. Trapping thus denotes a kinetically metastable state rather than thermodynamic equilibrium. This project probed mechanochemical means to polymerize select hydrocarbons in the presence of gases, in an attempt to form localized carbon cages that trap gases via repulsive interactions. Aromatic, polyaromatic, and hydroaromatic molecules expected to undergo cyclo-addition reactions were polymerized at high (~GPa) pressures to form extended hydrogenated amorphous carbon networks. Notably, aromatics with a pre-existing internal free volume (such as Triptycene) appeared to retain an internal porosity upon application of pressure. However, a high photoluminescence background after polymerization precluded in situ identification of trapped gases. No spectroscopic evidence was found after depressurization that would be indicative of pockets of trapped gases in a localized high-pressure environment. Control studies suggested this measurement may be insensitive to gases at low pressure. Similarly, no spectral fingerprint was found for gas-imbued spherical

  13. Technology mix alternatives with high shares of wind power and photovoltaics—case study for Spain

    International Nuclear Information System (INIS)

    Zubi, Ghassan

    2011-01-01

    The shift to a low carbon society is an issue of highest priority in the EU. For electricity generation, such a target counts with three main alternatives: renewable energies, nuclear power and carbon capture and storage. This paper focuses on the renewables’ alternative. Due to resource availability, a technology mix with a high share of PV and wind power is gaining increasing interest as a major solution for several EU member states and in part for the EU collectively to achieve decarbonization and energy security with acceptable costs. Due to their intermittency, the integration of high shares of PV and wind power in the electricity supply is challenging. This paper presents a techno-economic assessment of technology mix alternatives with a high share of PV and wind power in Spain, as an example. Thereby, the focus is on the option of increasing wind curtailment versus substituting rigid baseload generation in favor of the more flexible gas turbines and combined cycle gas turbines. - Highlights: ► The potential of power generation from renewable energy resources in the EU is illustrated. ► The LEC of the different technologies considered is calculated for today and future scenarios. ► An excel-based model for the technology mix assessment is applied using Spanish data. ► Technology mix alternatives with a high share of PV and wind power are assessed. ► The focus is on increasing wind curtailment vs. relying on more flexible power generation units.

  14. The carbon curse: Are fuel rich countries doomed to high CO2 intensities?

    International Nuclear Information System (INIS)

    Friedrichs, Jörg; Inderwildi, Oliver R.

    2013-01-01

    The carbon curse is a new theory, related to but distinct from the resource curse. It states that fossil-fuel rich countries tend to follow more carbon-intensive developmental pathways than [if they were] fossil-fuel poor countries, due to a hitherto unappreciated syndrome of causal mechanisms. First, fuel rich countries emit significant amounts of CO 2 in the extraction of fuel and through associated wasteful practices such as gas flaring. Second, easy access to domestic fuel in such countries leads to crowding-out effects for their energy mix and economic structure (for example, abundant oil may displace other fuels from the energy mix and lead to the “Dutch Disease”). Third, fuel abundance weakens the economic incentive to invest in energy efficiency. Fourth, governments in fuel rich countries are under considerable pressure to grant uneconomic fuel consumption subsidies, which further augments the carbon intensity of their economic output. Due to the combined effect of these causal mechanisms, it is genuinely difficult for fuel rich countries to evade carbon-intensive developmental pathways. And yet there are remarkable exceptions like Norway. Such positive outliers indicate that the carbon curse is not destiny when appropriate policies are adopted. - Highlights: • Fuel rich countries appear doomed to high carbon intensity, for four reasons. • First, extractive emissions; and, second, fuel-related crowding-out effects. • Third, weaker incentives to invest in improvements of energy efficiency. • Fourth, significant pressure to grant uneconomic fuel consumption subsidies. • But the carbon curse is not destiny, as indicated by positive outliers like Norway

  15. Comparative Environmental Life Cycle Assessment of Alternative Uses of Wastewater Carbon Content

    DEFF Research Database (Denmark)

    Kroghsbo, Nena; Nicolaisen, Janna; Wenzel, Henrik

    Alternative scenarios for the wastewater and sludge treatment configurations in urban wastewater treatment were studied with the aim of comparing their environmental aspects. As the reference, a conventional activated sludge treatment was chosen including a primary settling and biogas made from...... the mixed primary and secondary sludge. This reference was then compared to an alternative use of the mixed sludge for the fermentative generation of polyhydroxyalkanoates, PHA and subsequent use of the PHA to substitute polypropylene on the polymer markets. This comparison allows for assessing...... the environmental priorities between biogas and PHA formation from the carbon content of the sludge. Further, the elimination of the primary settling with the aim of using the carbon content of the wastewater for enhanced nitrogen removal in the activated sludge process was studied. This comparison allows...

  16. Mixing ratio sensor for alcohol mixed fuel

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Shigeru; Matsubara, Yoshihiro

    1987-08-24

    In order to improve the combustion efficiency of an internal combustion engine using gasoline-alcohol mixed fuel and to reduce harmful substance in its exhaust gas, it is necessary to control strictly the air-fuel ratio to be supplied and the ignition timing. In order to detect the mixing ratio of the mixed fuel, a mixing ratio sensor has so far been proposed to detect the above mixing ratio by casting a ray of light to the mixed fuel and utilizing a change of critical angle associated with the change of the composition of the fluid of the mixed fuel. However, because of the arrangement of its transparent substance in the fuel passage with the sealing material in between, this sensor invited the leakage of the fluid due to deterioration of the sealing material, etc. and its cost became high because of too many parts to be assembled. In view of the above, in order to reduce the number of parts, to lower the cost of parts and the assembling cost and to secure no fluid leakage from the fuel passage, this invention formed the above fuel passage and the above transparent substance both concerning the above mixing ratio sensor in an integrated manner using light transmitting resin. (3 figs)

  17. Applications of environmental tritium and carbon-14 in water resources investigation in Taiyuan region China

    International Nuclear Information System (INIS)

    Cai Zuhuang; Shi Huixin

    1988-01-01

    To evaluate the influence of exploiting karst groundwater by 0.5-1 cubic metre per second by Gujiao Coal Mine on the discharge rate of the major Lancun spring, Jinci spring and Xizhang waterworks in the Taiyuan region, Shanxi Province, and to seek new sources of water to make up for this influence, we carried out systematic hydrogeological studies in this region from 1983 to 1986, including measurement of 180 data of tritium, 49 data of carbon-13, 20 data of carbon-14, as well as more than 2,000 chemical data. Isotopic and chemical data were interpreted and used to distinguish the groundwater system, to determine the mixing ratios of various groundwaters, to trace the movement of groundwater both inside each subsystem and from one subsystem to another. Groundwater ages at 13 sites in the studied region were obtained after correction for mixing with young water, correction for dilution by dead carbon, and correction for variation of initial carbon-14 concentration. The velocity of groundwater flow was determined on the basis of groundwater ages. (author). 3 figs, 5 tabs

  18. Shear transfer in concrete reinforced with carbon fibers

    Science.gov (United States)

    El-Mokadem, Khaled Mounir

    2001-10-01

    Scope and method of study. The research started with preliminary tests and studies on the behavior and effect of carbon fibers in different water solutions and mortar/concrete mixes. The research work investigated the use of CF in the production of concrete pipes and prestressed concrete double-tee sections. The research then focused on studying the effect of using carbon fibers on the direct shear transfer of sand-lightweight reinforced concrete push-off specimens. Findings and conclusions. In general, adding carbon fibers to concrete improved its tensile characteristics but decreased its compressive strength. The decrease in compressive strength was due to the decrease in concrete density as fibers act as three-dimensional mesh that entrapped air. The decrease in compressive strength was also due to the increase in the total surface area of non-cementitious material in the concrete. Sand-lightweight reinforced concrete push-off specimens with carbon fibers had lower shear carrying capacity than those without carbon fibers for the same cement content in the concrete. Current building codes and specifications estimate the shear strength of concrete as a ratio of the compressive strength. If applying the same principals then the ratio of shear strength to compressive strength for concrete reinforced with carbon fibers is higher than that for concrete without carbon fibers.

  19. Photochemical mineralization of terrigenous DOC to dissolved inorganic carbon in ocean

    OpenAIRE

    Aarnos, Hanna; Gélinas, Yves; Kasurinen, Ville; Gu, Yufei; Puupponen, Veli-Mikko; Vähätalo, Anssi

    2018-01-01

    When terrigenous dissolved organic carbon (tDOC) rich in chromophoric dissolved organic matter (tCDOM) enters the ocean, solar radiation mineralizes it partially into dissolved inorganic carbon (DIC). This study addresses the amount and the rates of DIC photoproduction from tDOC and the area of ocean required to photomineralize tDOC. We collected water samples from 10 major rivers, mixed them with artificial seawater, and irradiated them with simulated solar radiation to measure DIC photoprod...

  20. Changes in carbon intensity in China. Empirical findings from 1980-2003

    International Nuclear Information System (INIS)

    Fan, Ying; Wei, Yi-Ming; Liu, Lan-Cui; Wu, Gang; Tsai, Hsien-Tang

    2007-01-01

    China experienced sustainable, rapid economic growth over the period 1980-2003 but, at the same time, energy-related carbon intensity showed a downward trend. It begs the question, therefore, what factors were driving this decline in carbon intensity and will this decline be maintained in future? Moreover, what measures can be adopted to ensure a continual decline in carbon intensity? These questions led to increased research in the factors governing CO 2 emission in China. This paper quantifies the driving force behind China's primary energy-related carbon intensity and measures the material production sectors' final energy-related carbon intensity. Our results show that the overwhelming contributor to the decline of energy-related carbon intensity was the reduction in real energy intensity. However, policies that focus only on the decline in energy intensity are insufficient to further decrease carbon intensity. The change of primary energy mix can improve the decline of carbon intensity. This should focus on the material production sectors' development strategies and final energy use. Greater emphasis should be given to secondary industry, which needs national and regional governments' policy support. (author)

  1. Global impact of carbon-14 from nuclear power reactors

    International Nuclear Information System (INIS)

    Moghissi, A.A.; Carter, M.W.

    1977-01-01

    Carbon-14 is produced by nuclear power reactors, predominently as a result of the interaction of a neutron and nitrogen-14 both in the fuel and in the coolant. Several other reactions also contribute to the production of carbon-14. Present operational procedures, in general, for reactors and fuel reprocessing plants result in the release of carbon-14 into the environment. Combustion of fossil fuels and certain industrial operations contribute to the supply of CO 2 in the atmosphere and this contribution is essentially free of carbon-14. Future carbon-14 burdens by assuming a thorough mixing of all CO 2 in the atmosphere is predicted. Available data on electric power generation, fossil fuel combustion and certain other information are used to calculate the projected specific activity of carbon-14 by the year 2000 and the twenty-first century. According to these calculations, the global population dose from carbon-14 can be substantial. Also, carbon-14 in the vicinity of nuclear power reactors is considered. Because of the chemistry of carbon-14, it is shown that local problems may be more significant around BWR's as compared to PWR's. Based on environmental considerations of carbon-14, its increasing production and discharge into the atmosphere, and available control technology, it is recommended that nitrogen use and its presence be minimized in pertinent reactor components and operations

  2. Fine-Grained Targets for Laser Synthesis of Carbon Nanotubes

    Science.gov (United States)

    Smith, Michael W. (Inventor); Park, Cheol (Inventor)

    2017-01-01

    A mechanically robust, binder-free, inexpensive target for laser synthesis of carbon nanotubes and a method for making same, comprising the steps of mixing prismatic edge natural flake graphite with a metal powder catalyst and pressing the graphite and metal powder mixture into a mold having a desired target shape.

  3. Analysis of carbon mitigation technology to 2050 in Japan through integrated energy economic model

    International Nuclear Information System (INIS)

    Komiyama, Ryoichi; Suzuki, Kengo; Nagatomi, Yu; Matsuo, Yuji; Suehiro, Shigeru

    2011-01-01

    This paper describes the outline of integrated energy economic model and calculated result concerning the outlook of energy and carbon dioxide emissions in Japan to 2050. The energy model developed in this paper is integrated one which consistently combines econometric model endogenously generating socio-economic outlook and bottom-up type technology model, MARKAL, identifying cost-minimizing optimal mix of various energy technologies. In reference scenario which imposes no carbon emissions constraint, CO 2 emission in 2050 will decrease by approximately 40% from the level of emissions in 2005. In carbon-constraints scenario, imposing emissions cap of 60% reduction by 2050 from the emissions in 2005, natural gas-fired power plant equipped with CCS and renewable energy are expected to expand its portion in power generation mix. In transportation sector on this scenario, clean energy vehicles such as electric vehicle (EV) and hydrogen fuel cell vehicle (FCV) will be deployed and contribute to mitigate CO 2 emissions. (author)

  4. The Effect of Nitrogen Ion Implantation on the Surface Properties of Ti6Al4V Alloy Coated by a Carbon Nanolayer

    Directory of Open Access Journals (Sweden)

    Petr Vlcak

    2013-01-01

    Full Text Available The ion beam assisted deposition (IBAD method was chosen for preparing a carbon thin film with a mixing area on a substrate of Ti6Al4V titanium alloy. Nitrogen ions with energy 90 keV were used. These form a broad ion beam mixing area at the interface between the carbon film and the substrate. We investigated the chemical composition by the glow discharge optical emission spectroscopy (GD-OES method and the phases by the X-ray diffraction (XRD method. The measured concentration profiles indicate the mixing of the carbon film into the substrate, which may have an effect on increasing the adhesion of the deposited film. The nanohardness and the coefficient of friction were measured. We found that the modified samples had a markedly lower coefficient of friction even after damage to the carbon film, and they also had higher nanohardness than the unmodified samples. The increased nanohardness is attributed to the newly created phases that arose with ion implantation of nitrogen ions.

  5. 1km Global Terrestrial Carbon Flux: Estimations and Evaluations

    Science.gov (United States)

    Murakami, K.; Sasai, T.; Kato, S.; Saito, M.; Matsunaga, T.; Hiraki, K.; Maksyutov, S. S.

    2017-12-01

    Estimating global scale of the terrestrial carbon flux change with high accuracy and high resolution is important to understand global environmental changes. Furthermore the estimations of the global spatiotemporal distribution may contribute to the political and social activities such as REDD+. In order to reveal the current state of terrestrial carbon fluxes covering all over the world and a decadal scale. The satellite-based diagnostic biosphere model is suitable for achieving this purpose owing to observing on the present global land surface condition uniformly at some time interval. In this study, we estimated the global terrestrial carbon fluxes with 1km grids by using the terrestrial biosphere model (BEAMS). And we evaluated our new carbon flux estimations on various spatial scales and showed the transition of forest carbon stocks in some regions. Because BEAMS required high resolution meteorological data and satellite data as input data, we made 1km interpolated data using a kriging method. The data used in this study were JRA-55, GPCP, GOSAT L4B atmospheric CO2 data as meteorological data, and MODIS land product as land surface satellite data. Interpolating process was performed on the meteorological data because of insufficient resolution, but not on MODIS data. We evaluated our new carbon flux estimations using the flux tower measurement (FLUXNET2015 Datasets) in a point scale. We used 166 sites data for evaluating our model results. These flux sites are classified following vegetation type (DBF, EBF, ENF, mixed forests, grass lands, croplands, shrub lands, Savannas, wetlands). In global scale, the BEAMS estimations was underestimated compared to the flux measurements in the case of carbon uptake and release. The monthly variations of NEP showed relatively high correlations in DBF and mixed forests, but the correlation coefficients of EBF, ENF, and grass lands were less than 0.5. In the meteorological factors, air temperature and solar radiation showed

  6. Formation of mixed organic layers by stepwise electrochemical reduction of diazonium compounds.

    Science.gov (United States)

    Santos, Luis; Ghilane, Jalal; Lacroix, Jean Christophe

    2012-03-28

    This work describes the formation of a mixed organic layer covalently attached to a carbon electrode. The strategy adopted is based on two successive electrochemical reductions of diazonium salts. First, bithiophene phenyl (BTB) diazonium salt is reduced using host/guest complexation in a water/cyclodextrin (β-CD) solution. The resulting layer consists of grafted BTB oligomers and cyclodextrin that can be removed from the surface. The electrochemical response of several outer-sphere redox probes on such BTB/CD electrodes is close to that of a diode, thanks to the easily p-dopable oligo(BTB) moieties. When CD is removed from the surface, pinholes are created and this diode like behavior is lost. Following this, nitrophenyl (NP) diazonium is reduced to graft a second component. Electrochemical study shows that upon grafting NP insulating moieties, the diode-like behavior of the layer is restored which demonstrates that NP is grafted predominately in the empty spaces generated by β-CD desorption. As a result, a mixed BTB/NP organic layer covalently attached to a carbon electrode is obtained using a stepwise electrochemical reduction of two diazonium compounds.

  7. High-temperature vaporization of thorium-uranium mixed monocarbide (Th1-y, Uy)C

    International Nuclear Information System (INIS)

    Koyama, Tadafumi; Yamawaki, Michio

    1989-01-01

    Vaporization thermodynamics of thorium-uranium mixed monocarbide phase (Th 1-y , U y )C was studied by mass spectrometric Knudsen effusion method for the compositions of (Th 0.9 , U 0.1 )C 0.855 , (Th 0.8 , U 0.2 )C 0.973 and (Th 0.6 , U 0.4 )C 0.973 . The partial vapor pressures of Th(g) and U(g) and activities of Th and U of these mixed monocarbides were determined at temperatures ranging from about 2000 to 2200 K. Further, the partial pressures of Th(g) and U(g) and activities of Th and U of the stoichiometric mixed monocarbides (Th 1-y , U y )C 1.00 were evaluated by compensating for the effect of carbon content. The Gibbs energies of formation of stoichiometric (Th 1-y , U y )C 1.00 were also evaluated. (orig.)

  8. Remediating the INEL's buried mixed waste tanks

    International Nuclear Information System (INIS)

    Kuhns, D.J.; Matthern, G.E.; Reese, C.L.

    1996-01-01

    The Idaho National Engineering Laboratory (INEL), formerly the National Reactor Testing Station (NRTS), encompasses 890 square miles and is located in southeast Idaho. In 1949, the United States Atomic Energy Commission, now the Department of Energy (DOE), established the NRTS as a site for the building and testing of nuclear facilities. Wastes generated during the building and testing of these nuclear facilities were disposed within the boundaries of the site. These mixed wastes, containing radionuclides and hazardous materials, were often stored in underground tanks for future disposal. The INEL has 11 buried mixed waste storage tanks regulated under the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) ranging in size from 400 to 50,000 gallons. These tanks are constructed of either stainless or carbon steel and are located at 3 distinct geographic locations across the INEL. These tanks have been grouped based on their similarities in an effort to save money and decrease the time required to complete the necessary remediation. Environmental Restoration and Technology Development personnel are teaming in an effort to address the remediation problem systematically

  9. In-situ stabilization of mixed waste contaminated soil

    International Nuclear Information System (INIS)

    Siegrist, R.L.; Cline, S.R.; Gilliam, T.M.; Conner, J.R.

    1993-01-01

    A full-scale field demonstration was conducted to evaluate in for stabilizing an inactive RCRA land treatment site at a DOE facility in Ohio. Subsurface silt and clay deposits were contaminated principally with up to 500 mg/kg of trichloroethylene and other halocarbons, but also trace to low levels of Pb, Cr, 235 U, and 99 Tc. In situ solidification was studied in three, 3.1 m diameter by 4.6 m deep columns. During mixing, a cement-based grout was injected and any missions from the mixed region were captured in a shroud and treated by filtration and carbon adsorption. During in situ processing, operation and performance parameters were measured, and soil cores were obtained from a solidified column 15 months later. Despite previous site-specific treatability experience, there were difficulties in selecting a grout with the requisite treatment agents amenable to subsurface injection and at a volume adequate for distribution throughout the mixed region while minimizing volume expansion. observations during the demonstration revealed that in situ solidification was rapidly accomplished (e.g., >90 m 3 /d) with limited emissions of volatile organics (i.e., -6 cm/s vs. 10 -8 cm/s). Leaching tests performed on the treated samples revealed non-detectable to acceptably low concentrations of all target contaminants

  10. Effect of carbon dioxide and bicarbonate as inorganic carbon sources on growth and adaptation of autohydrogenotrophic denitrifying bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ghafari, Shahin; Hasan, Masitah [Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Aroua, Mohamed Kheireddine [Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)], E-mail: mk_aroua@um.edu.my

    2009-03-15

    Acclimation of autohydrogenotrophic denitrifying bacteria using inorganic carbon source (CO{sub 2} and bicarbonate) and hydrogen gas as electron donor was performed in this study. In this regard, activated sludge was used as the seed source and sequencing batch reactor (SBR) technique was applied for accomplishing the acclimatization. Three distinct strategies in feeding of carbon sources were applied: (I) continuous sparging of CO{sub 2}, (II) bicarbonate plus continuous sparging of CO{sub 2}, and (III) only bicarbonate. The pH-reducing nature of CO{sub 2} showed an unfavorable impact on denitrification rate; however bicarbonate resulted in a buffered environment in the mixed liquor and provided a suitable mean to maintain the pH in the desirable range of 7-8.2. As a result, bicarbonate as the only carbon source showed a faster adaptation, while carbon dioxide as the only carbon source as well as a complementary carbon source added to bicarbonate resulted in longer acclimation period. Adapted hydrogenotrophic denitrifying bacteria, using bicarbonate and hydrogen gas in the aforementioned pH range, caused denitrification at a rate of 13.33 mg NO{sub 3}{sup -}-N/g MLVSS/h for degrading 20 and 30 mg NO{sub 3}{sup -}-N/L and 9.09 mg NO{sub 3}{sup -}-N/g MLVSS/h for degrading 50 mg NO{sub 3}{sup -}-N/L.

  11. REE in the Griqualand-West carbonates - evidence for seawater/fresh water mixing?

    International Nuclear Information System (INIS)

    Danielson, A.

    1990-01-01

    The investigated sample material is derived from the carbonate buildup of the Transvaal Supergoup in an area between Schmitsdrift and Griquatown and Danielskuil and Douglas. Out of the stratigraphic sequence samples from seven formations have been analyzed. The studied material represents a wide range of environmental settings, from platform margin up to intertidal conditions. Various stages of dolomitization are present. 1 ref., 1 fig

  12. Evaluating the electrical discharge machining (EDM) parameters with using carbon nanotubes

    Science.gov (United States)

    Sari, M. M.; Noordin, M. Y.; Brusa, E.

    2012-09-01

    Electrical discharge machining (EDM) is one of the most accurate non traditional manufacturing processes available for creating tiny apertures, complex or simple shapes and geometries within parts and assemblies. Performance of the EDM process is usually evaluated in terms of surface roughness, existence of cracks, voids and recast layer on the surface of product, after machining. Unfortunately, the high heat generated on the electrically discharged material during the EDM process decreases the quality of products. Carbon nanotubes display unexpected strength and unique electrical and thermal properties. Multi-wall carbon nanotubes are therefore on purpose added to the dielectric used in the EDM process to improve its performance when machining the AISI H13 tool steel, by means of copper electrodes. Some EDM parameters such as material removal rate, electrode wear rate, surface roughness and recast layer are here first evaluated, then compared to the outcome of EDM performed without using nanotubes mixed to the dielectric. Independent variables investigated are pulse on time, peak current and interval time. Experimental evidences show that EDM process operated by mixing multi-wall carbon nanotubes within the dielectric looks more efficient, particularly if machining parameters are set at low pulse of energy.

  13. Evaluating the electrical discharge machining (EDM) parameters with using carbon nanotubes

    International Nuclear Information System (INIS)

    Sari, M M; Brusa, E; Noordin, M Y

    2012-01-01

    Electrical discharge machining (EDM) is one of the most accurate non traditional manufacturing processes available for creating tiny apertures, complex or simple shapes and geometries within parts and assemblies. Performance of the EDM process is usually evaluated in terms of surface roughness, existence of cracks, voids and recast layer on the surface of product, after machining. Unfortunately, the high heat generated on the electrically discharged material during the EDM process decreases the quality of products. Carbon nanotubes display unexpected strength and unique electrical and thermal properties. Multi-wall carbon nanotubes are therefore on purpose added to the dielectric used in the EDM process to improve its performance when machining the AISI H13 tool steel, by means of copper electrodes. Some EDM parameters such as material removal rate, electrode wear rate, surface roughness and recast layer are here first evaluated, then compared to the outcome of EDM performed without using nanotubes mixed to the dielectric. Independent variables investigated are pulse on time, peak current and interval time. Experimental evidences show that EDM process operated by mixing multi-wall carbon nanotubes within the dielectric looks more efficient, particularly if machining parameters are set at low pulse of energy.

  14. Carbon dioxide selective adsorption within a highly stable mixed-ligand Zeolitic Imidazolate Framework

    KAUST Repository

    Huang, Lin; Xue, Ming; Song, Qingshan; Chen, Siru; Pan, Ying; Qiu, Shilun

    2014-01-01

    A new mixed-ligand Zeolitic Imidazolate Framework Zn4(2-mbIm) 3(bIm)5·4H2O (named JUC-160, 2-mbIm = 2-methylbenzimidazole, bIm = benzimidazole and JUC = Jilin University China) was synthesized with a solvothermal reaction of Zn(NO3) 2·6H2O, b

  15. Improvement of deposition efficiency and control of hardness for cold-sprayed coatings using high carbon steel/mild steel mixture powder

    International Nuclear Information System (INIS)

    Ogawa, Kazuhiro; Amao, Satoshi; Yokoyama, Nobuyuki; Ootaki, Kousuke

    2011-01-01

    In this study, in order to make high carbon steel coating by cold spray technique, spray conditions such as carrier gas temperature and pressure etc. were investigated. And also, in order to improve deposition efficiency and control coating hardness of cold-sprayed high carbon steel, high carbon and mild steel mixed powder and its mechanical milled powder were developed and were optimized. By using the cold-spray technique, particle deposition of a high carbon steel was successful. Moreover, by applying mixed and mechanical milled powders, the porosity ratio was decreased and deposition efficiency was improved. Furthermore, using these powders, it is possible to control the hardness value. Especially, when using mechanical milled powder, it is very difficult to identify the interface between the coating and the substrate. The bonding between the coating and the substrate is thus considered to be excellent. (author)

  16. Dimethylamine biodegradation by mixed culture enriched from drinking water biofilter.

    Science.gov (United States)

    Liao, Xiaobin; Chen, Chao; Zhang, Jingxu; Dai, Yu; Zhang, Xiaojian; Xie, Shuguang

    2015-01-01

    Dimethylamine (DMA) is one of the important precursors of drinking water disinfection by-product N-nitrosodimethylamine (NDMA). Reduction of DMA to minimize the formation of carcinogenic NDMA in drinking water is of practical importance. Biodegradation plays a major role in elimination of DMA pollution in the environment, yet information on DMA removal by drinking water biofilter is still lacking. In this study, microcosms with different treatments were constructed to investigate the potential of DMA removal by a mixed culture enriched from a drinking water biofilter and the effects of carbon and nitrogen sources. DMA could be quickly mineralized by the enrichment culture. Amendment of a carbon source, instead of a nitrogen source, had a profound impact on DMA removal. A shift in bacterial community structure was observed with DMA biodegradation, affected by carbon and nitrogen sources. Proteobacteria was the predominant phylum group in DMA-degrading microcosms. Microorganisms from a variety of bacterial genera might be responsible for the rapid DMA mineralization. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Mediated electrochemical oxidation of mixed wastes

    International Nuclear Information System (INIS)

    Chiba, Z.

    1993-04-01

    The Mediated Electrochemical Oxidation (MEO) process was studied for destroying low-level combustible mixed wastes at Rocky Flats Plant. Tests were performed with non-radioactive surrogate materials: Trimsol for contaminated cutting oils, and reagent-grade cellulose for contaminated cellulosic wastes. Extensive testing was carried out on Trimsol in both small laboratory-scale apparatus and on a large-scale system incorporating an industrial-size electrochemical cell. Preliminary tests were also carried out in the small-scale system with cellulose. Operating and system parameters that were studied were: use of a silver-nitric acid versus a cobalt-sulfuric acid system, effect of electrolyte temperature, effect of acid concentration, and effect of current density. Destruction and coulombic efficiencies were calculated using data obtained from continuous carbon dioxide monitors and total organic carbon (TOC) analysis of electrolyte samples. For Trimsol, the best performance was achieved with the silver-nitrate system at high acid concentrations, temperatures, and current densities. Destruction efficiencies of 99% or greater, and coulombic efficiencies up to 70% were obtained. For the cellulose, high destruction efficiencies and reasonable coulombic efficiencies were obtained for both silver-nitrate and cobalt-sulfate systems

  18. Economic effects of a carbon tax in Belgium

    International Nuclear Information System (INIS)

    Bossier, F.; De Rous, R.

    1992-01-01

    This paper proposes to evaluate the consequences of the introduction of a carbon tax for the Belgian economy. To this end, two scenarios are studied. The first scenario introduces a carbon tax of about 23.5 ecus per ton of CO 2 emitted and the second scenario combines the tax with incentives to energy savings investments. The results suggest that the tax, alone, is not sufficient to meet the international requirements as far as a stabilization of CO 2 emissions is required. It is therefore suggested that a policy-mix of pure taxation measures with various forms of subsidies to investments should be achieved. (author)

  19. Extrusion-mixing compared with hand-mixing of polyether impression materials?

    Science.gov (United States)

    McMahon, Caroline; Kinsella, Daniel; Fleming, Garry J P

    2010-12-01

    The hypotheses tested were two-fold (a) whether altering the base:catalyst ratio influences working time, elastic recovery and strain in compression properties of a hand-mixed polyether impression material and (b) whether an extrusion-mixed polyether impression material would have a significant advantage over a hand-mixed polyether impression material mixed to the optimum base:catalyst ratio. The polyether was hand-mixed at the optimum (manufacturers recommended) base:catalyst ratios (7:1) and further groups were made by increasing or decreasing the catalyst length by 25%. Additionally specimens were also made from an extrusion-mixed polyether impression material and compared with the optimum hand-mixed base:catalyst ratio. A penetrometer assembly was used to measure the working time (n=5). Five cylindrical specimens for each hand-mixed and extrusion mixed group investigated were employed for elastic recovery and strain in compression testing. Hand-mixing polyether impression materials with 25% more catalyst than that recommended significantly decreased the working time while hand-mixing with 25% less catalyst than that recommended significantly increased the strain in compression. The extrusion-mixed polyether impression material provided similar working time, elastic recovery and strain in compression to the hand-mixed polyether mixed at the optimum base:catalyst ratio.

  20. ESTIMATION OF CARBON SEQUESTRATION BY RUSSIAN FORESTS: GEOSPATIAL ISSUE

    Directory of Open Access Journals (Sweden)

    N. V. Malysheva

    2017-01-01

    Full Text Available Сategories of carbon sequestration assessment for Russian forests are identified by GIS toolkit. Those are uniform by bioclimatic and site-specific conditions strata corresponding to modern version of bioclimatic forest district division. Stratification of forests at early stage substantially reduces the ambiguity of the evaluation because phytomass conversion sequestration capacity and expansion factor dependent on site-specific condition for calculating of forest carbon sink are absolutely necessary. Forest management units were linked to strata. Biomass conversion and expansion factor for forest carbon sink assessment linked to the strata were recalculated for forest management units. All operations were carried out with GIS analytical toolkit due to accessible functionalities. Units for forest carbon storage inventory and forest carbon balance calculation were localized. Production capacity parameters and forest carbon sequestration capacity have been visualized on maps complied by ArcGIS. Based on spatially-explicit information, we have found out that the greatest annual rates of forest’s carbon accumulation in Russian forests fall into mixed coniferous-deciduous forests of European-Ural part of Russia to Kaliningrad, Smolensk and Briansk Regions, coniferous-deciduous forests close to the boundary of Khabarovsk Region and Primorskij Kray in the Far East, as well as separate forest management units of Kabardino-Balkariya NorthCaucasian mountain area. The geospatial visualization of carbon sequestration by Russian forests and carbon balance assessment has been given.

  1. Enhanced gasification of wood in the presence of mixed catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Weber, S. L.; Mudge, L. K.; Sealock, Jr., L. J.; Robertus, R. J.; Mitchell, D. E.

    Experimental results obtained in laboratory investigations of steam gasification of wood in the presence of mixed catalysts are presented. These studies are designed to test the technical feasibility of producing specific gaseous products from wood by enhancing its reactivity and product specificity through the use of combined catalysts. The desired products include substitute natural gas, hydrocarbon synthesis gas and ammonia synthesis gas. The gasification reactions are controlled through the use of specific catalyst combinations and operating parameters. A primary alkali carbonate gasification catalyst impregnated into the wood combined with specific commercially available secondary catalysts produced the desired products. A yield of 50 vol % methane was obtained with a randomly mixed combination of a commercial nickel methanation catalyst and silica-alumina cracking catalyst at a weight ratio of 3:1 respectively. Steam gasification of wood in the presence of a commercial Si-Al cracking catalyst produced the desired hydrocarbon synthesis gas. Hydrogen-to-carbon monoxide ratios needed for Fischer-Tropsch synthesis of hydrocarbons were obtained with this catalyst system. A hydrogen-to-nitrogen ratio of 3:1 for ammonia synthesis gas was achieved with steam-air gasification of wood in the presence of catalysts. The most effective secondary catalyst system employed to produce the ammonia synthesis gas included two commercially prepared catalysts formulated to promote the water-gas shift reaction.

  2. Assessment of the possible future climatic impact of carbon dioxide increases based on a coupled one-dimensional atmospheric-oceanic model

    International Nuclear Information System (INIS)

    Hunt, B.G.; Wells, N.C.

    1979-01-01

    A radiative-convective equilibrium model of the atmosphere has been coupled with a mixed layer model of the ocean to investigate the response of this one-dimensional system to increasing carbon dioxide amounts in the atmosphere. For global mean conditions a surface temperature rise of about 2 0 K was obtained for a doubling of the carbon dioxide amount, in reasonable agreement with the commonly accepted results of Manabe and Wetherald. This temperature rise was essentially invariant with season and indicates that including a shallow (300 m) ocean slab in this problem does not basically alter previous assessments. While the mixed layer depth of the ocean was only very slightly changed by the temperature increase, which extended throughout the depth of the mixed layer, the impact of this increase on the overall behavior of the ocean warrants further study. A calculation was also made of the temporal variation of the sea surface temperature for three possible carbon dioxide growth rates starting from an initial carbon dioxide content of 300 ppm. This indicated that the thermal inertia of the slab ocean provides a time lag of 8 years in the sea surface temperature response compared to a land situation. This is not considered to be of great significance as regards the likely future climatic impact of carbon dioxide increase

  3. Balancing carbon/nitrogen ratio to improve nutrients removal and algal biomass production in piggery and brewery wastewaters.

    Science.gov (United States)

    Zheng, Hongli; Liu, Mingzhi; Lu, Qian; Wu, Xiaodan; Ma, Yiwei; Cheng, Yanling; Addy, Min; Liu, Yuhuan; Ruan, Roger

    2018-02-01

    To improve nutrients removal from wastewaters and enhance algal biomass production, piggery wastewater was mixed with brewery wastewaters. The results showed that it was a promising way to cultivate microalga in piggery and brewery wastewaters by balancing the carbon/nitrogen ratio. The optimal treatment condition for the mixed piggery-brewery wastewater using microalga was piggery wastewater mixed with brewery packaging wastewater by 1:5 at pH 7.0, resulting in carbon/nitrogen ratio of 7.9, with the biomass concentration of 2.85 g L -1 , and the removal of 100% ammonia, 96% of total nitrogen, 90% of total phosphorus, and 93% of chemical oxygen demand. The application of the established strategies can enhance nutrient removal efficiency of the wastewaters while reducing microalgal biomass production costs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Driving forces of organic carbon spatial distribution in the tropical seascape

    Science.gov (United States)

    Gillis, L. G.; Belshe, F. E.; Ziegler, A. D.; Bouma, T. J.

    2017-02-01

    An important ecosystem service of tropical coastal vegetation including seagrass beds and mangrove forests is their ability to accumulate carbon. Here we attempt to establish the driving forces for the accumulation of surface organic carbon in southern Thailand coastal systems. Across 12 sites we found that in line with expectations, seagrass beds (0.6 ± 0.09%) and mangrove forests (0.9 ± 0.3%) had higher organic carbon in the surface (top 5 cm) sediment than un-vegetated mudflats (0.4 ± 0.04%). Unexpectedly, however, mangrove forests in this region retained organic carbon, rather than outwell it, under normal tidal conditions. No relationship was found between organic carbon and substrate grain size. The most interesting finding of our study was that climax and pioneer seagrass species retained more carbon than mixed-species meadows, suggesting that plant morphology and meadow characteristics can be important factors in organic carbon accumulation. Insights such as these are important in developing carbon management strategies involving coastal ecosystems such as offsetting of carbon emissions. The ability of tropical coastal vegetation to sequester carbon is an important aspect for valuing the ecosystems. Our results provide some initial insight into the factors affecting carbon sequestration in these ecosystems, but also highlight the need for further research on a global scale.

  5. Investigation of the potential of coal combustion fly ash for mineral sequestration of CO2 by accelerated carbonation

    International Nuclear Information System (INIS)

    Ukwattage, N.L.; Ranjith, P.G.; Wang, S.H.

    2013-01-01

    Mineral carbonation of alkaline waste materials is being studied extensively for its potential as a way of reducing the increased level of CO 2 in the atmosphere. Carbonation converts CO 2 into minerals which are stable over geological time scales. This process occurs naturally but slowly, and needs to be accelerated to offset the present rate of emissions from power plants and other emission sources. The present study attempts to identify the potential of coal fly ash as a source for carbon storage (sequestration) through ex-situ accelerated mineral carbonation. In the study, two operational parameters that could affect the reaction process were tested to investigate their effect on mineralization. Coal fly ash was mixed with water to different water-to-solid ratios and samples were carbonated in a pressure vessel at different initial CO 2 pressures. Temperature was kept constant at 40 °C. According to the results, one ton of Hazelwood fly ash could sequester 7.66 kg of CO 2 . The pressure of CO 2 inside the vessel has an effect on the rate of CO 2 uptake and the water-to-solid ratio affects the weight gain after the carbonation of fly ash. The results confirm the possibility of the manipulation of process parameters in enhancing the carbonation reaction. - Highlights: ► Mineral sequestration CO 2 by of coal fly ash is a slow process under ambient conditions. ► It can be accelerated by manipulating the process parameters inside a reactor. ► Initial CO 2 pressure and water to solid mixing ratio inside the reactor are two of those operational parameters. ► According to the test results higher CO 2 initial pressure gives higher on rates of CO 2 sequestration. ► Water to fly ash mixing ratio effect on amount of CO 2 sequestered into fly ash

  6. Deposition of carbon nitride films by vacuum ion diode with explosive emission

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, S.A.; Perry, A.J. [New Jersey Inst. of Tech., Newark (United States); Elkind, A.; Kalmukov, A.

    1997-10-31

    Carbon nitride films were synthesized using a novel technique based on the pulsed high voltage ion/electron diode with explosive emission (pulsed voltage 200-700 kV pulsed current 100-500 Acm{sup -2} (ions) 150-2000 Acm{sup -2} (electrons)). The method and its novel features are discussed as well as its application to the formation of the crystalline {beta}-phase in C{sub 3}N{sub 4} films. Mixed elemental nitrogen and carbon films are formed by sequential deposition then subjected to ion and/or electron beam mixing to synthesize the C{sub 3}N{sub 4} structure. The experimental conditions used for this pulsed process are described and the efficiency of the method for nitrogen incorporation is demonstrated. The results presented indicate that {beta}-C{sub 3}N{sub 4} crystallites are formed in an amorphous matrix. (orig.) 20 refs.

  7. Effect of carbon black on thermal properties of charcoal and salacca leafstalk briquettes

    Science.gov (United States)

    Thassana, Chewa; Nuleg, Witoon

    2017-08-01

    In this work, the effect of a carbon black (CB) on the thermal properties of briquettes produced from the charcoal and the salacca leafstalk with and without CB have been investigated. Four thermal properties of a briquettes compose of the burning time, the calorific value, the percentage moisture (PMC) and an percentage ash content (PAC) were analyzed using standard laboratory methods. Our results were indicated that the sallacca leafstalk mix a carbon black is the long burning times, high heating but a few ash content. Results shown that the burning time and the calorific value of a charcoal, a charcoal with CB, the salacca leafstalk and the salacca leafstalk with carbon black particles is about 58, 63, 76, 81 minutes, and 10.33, 12.96, 13.12, 14.63 MJ/kg, respectively. In addition, the PMC and PAC were in range of 11.6 - 8.14% and 9.33 - 5.42%. So, we can conclude that a cabon black affect on the thermal properties of a briquettes and salacca leaftstalk mixed CB has been most suited for briquetting.

  8. Inorganic synthesis of Fe-Ca-Mg carbonates at low temperature

    NARCIS (Netherlands)

    Romanek, Christopher S.; Jiménez-López, Concepción; Navarro, Alejandro Rodriguez; Sánchez-Román, Monica; Sahai, Nita; Coleman, Max

    2009-01-01

    A set of free-drift experiments was undertaken to synthesize carbonates of mixed cation content (Fe, Ca, Mg) from solution at 25 and 70 °C to better understand the relationship between the mineralogy and composition of these phases and the solutions from which they precipitate. Metastable solid

  9. Whole Watershed Quantification of Net Carbon Fluxes by Erosion and Deposition within the Christina River Basin Critical Zone Observatory

    Science.gov (United States)

    Aufdenkampe, A. K.; Karwan, D. L.; Aalto, R. E.; Marquard, J.; Yoo, K.; Wenell, B.; Chen, C.

    2013-12-01

    We have proposed that the rate at which fresh, carbon-free minerals are delivered to and mix with fresh organic matter determines the rate of carbon preservation at a watershed scale (Aufdenkampe et al. 2011). Although many studies have examined the role of erosion in carbon balances, none consider that fresh carbon and fresh minerals interact. We believe that this mechanism may be a dominant sequestration process in watersheds with strong anthropogenic impacts. Our hypothesis - that the rate of mixing fresh carbon with fresh, carbon-free minerals is a primary control on watershed-scale carbon sequestration - is central to our Christina River Basin Critical Zone Observatory project (CRB-CZO, http://www.udel.edu/czo/). The Christina River Basin spans 1440 km2 from piedmont to Atlantic coastal plain physiographic provinces in the states of Pennsylvania and Delaware, and experienced intensive deforestation and land use beginning in the colonial period of the USA. Here we present a synthesis of multi-disciplinary data from the CRB-CZO on materials as they are transported from sapprolite to topsoils to colluvium to suspended solids to floodplains, wetlands and eventually to the Delaware Bay estuary. At the heart of our analysis is a spatially-integrated, flux-weighted comparison of the organic carbon to mineral surface area ratio (OC/SA) of erosion source materials versus transported and deposited materials. Because source end-members - such as forest topsoils, farmed topsoils, gullied subsoils and stream banks - represent a wide distribution of initial, pre-erosion OC/SA, we quantify source contributions using geochemical sediment fingerprinting approaches (Walling 2005). Analytes used for sediment fingerprinting include: total mineral elemental composition (including rare earth elements), fallout radioisotope activity for common erosion tracers (beryllium-7, beryllium-10, lead-210, cesium-137), particle size distribution and mineral specific surface area, in addition

  10. Carbon emissions and management scenarios for consumer-owned utilities

    International Nuclear Information System (INIS)

    Fischlein, Miriam; Smith, Timothy M.; Wilson, Elizabeth J.

    2009-01-01

    An important subset of the utility sector has been scarcely explored for its ability to reduce carbon dioxide emissions: consumer-owned electric utilities significantly contribute to U.S. greenhouse gas emissions, but are often excluded from energy efficiency and renewable energy policies. They sell a quarter of the nation's electricity, yet the carbon impact of these sales is not well understood, due to their small size, unique ownership models, and high percentage of purchased power for distribution. This paper situates consumer-owned utilities in the context of emerging U.S. climate policy, quantifying for the first time the state-by-state carbon impact of electricity sales by consumer-owned utilities. We estimate that total retail sales by consumer-owned utilities account for roughly 568 million metric tons of CO 2 annually, making this sector the 7th largest CO 2 emitter globally, and examine state-level carbon intensities of the sector in light of the current policy environment and the share of COU distribution in the states. Based on efficiency and fuel mix pathways under conceivable regulations, carbon scenarios for 2030 are developed.

  11. Natural gas central to world's future energy mix

    International Nuclear Information System (INIS)

    Carson, M.M.

    1997-01-01

    Continued growth in demand for natural gas is one of three pillars around which the energy mix of the future will take shape and upon which energy strategies should be based. The others are consumption efficiency and growth of renewable energy sources. This paper evaluates world energy supply and demand and includes an analysis of world pipeline gas, electricity, and LNG trends. The paper discusses the natural gas resource, proved reserves, reserves growth, gas prices and demand, country demand trends, world energy use, gas pipeline construction, power generation, electricity consumption and prices, and global carbon emissions

  12. Contributions of secondary fragmentation by carbon ion beams in water phantom: Monte Carlo simulation

    International Nuclear Information System (INIS)

    Ying, C K; Bolst, David; Tran, Linh T.; Guatelli, Susanna; Rosenfeld, A. B.; Kamil, W A

    2017-01-01

    Heavy-particle therapy such as carbon ion therapy is currently very popular because of its superior conformality in terms of dose distribution and higher Relative Biological Effectiveness (RBE). However, carbon ion beams produce a complex mixed radiation field, which needs to be fully characterised. In this study, the fragmentation of a 290 MeV/u primary carbon ion beam was studied using the Geant4 Monte Carlo Toolkit. When the primary carbon ion beam interacts with water, secondary light charged particles (H, He, Li, Be, B) and fast neutrons are produced, contributing to the dose, especially after the distal edge of the Bragg peak. (paper)

  13. Development and Characterization of Defect-Free Matrimid® Mixed-Matrix Membranes Containing Activated Carbon Particles for Gas Separation

    Directory of Open Access Journals (Sweden)

    Fynn Weigelt

    2018-01-01

    Full Text Available In this work, mixed-matrix membranes (MMMs for gas separation in the form of thick films were prepared via the combination of the polymer Matrimid® 5218 and activated carbons (AC. The AC particles had a mean particle size of 1.5 μm and a mean pore diameter of 1.9 nm. The films were prepared by slow solvent evaporation from casting solutions in chloroform, which had a varying polymer–AC ratio. It was possible to produce stable films with up to a content of 50 vol % of AC. Thorough characterization experiments were accomplished via differential scanning calorimetry and thermogravimetric analysis, while the morphology of the MMMs was also investigated via scanning electron microscopy. The gas transport properties were revealed by employing time-lag measurements for different pure gases as well as sorption balance experiments for the filler particles. It was found that defect free Matrimid® MMMs with AC were prepared and the increase of the filler content led to a higher effective permeability for different gases. The single gas selectivity αij of different gas pairs maintained stable values with the increase of AC content, regardless of the steep increase in the effective permeability of the pure gases. Estimation of the solubilities and the diffusivities of the Matrimid®, AC, and MMMs allowed for the explanation of the increasing permeabilities of the MMMs, with the increase of AC content by modelling.

  14. Enhanced solar energy absorption by internally-mixed black carbon in snow grains

    Directory of Open Access Journals (Sweden)

    M. G. Flanner

    2012-05-01

    Full Text Available Here we explore light absorption by snowpack containing black carbon (BC particles residing within ice grains. Basic considerations of particle volumes and BC/snow mass concentrations show that there are generally 0.05–109 BC particles for each ice grain. This suggests that internal BC is likely distributed as multiple inclusions within ice grains, and thus the dynamic effective medium approximation (DEMA (Chýlek and Srivastava, 1983 is a more appropriate optical representation for BC/ice composites than coated-sphere or standard mixing approximations. DEMA calculations show that the 460 nm absorption cross-section of BC/ice composites, normalized to the mass of BC, is typically enhanced by factors of 1.8–2.1 relative to interstitial BC. BC effective radius is the dominant cause of variation in this enhancement, compared with ice grain size and BC volume fraction. We apply two atmospheric aerosol models that simulate interstitial and within-hydrometeor BC lifecycles. Although only ~2% of the atmospheric BC burden is cloud-borne, 71–83% of the BC deposited to global snow and sea-ice surfaces occurs within hydrometeors. Key processes responsible for within-snow BC deposition are development of hydrophilic coatings on BC, activation of liquid droplets, and subsequent snow formation through riming or ice nucleation by other species and aggregation/accretion of ice particles. Applying deposition fields from these aerosol models in offline snow and sea-ice simulations, we calculate that 32–73% of BC in global surface snow resides within ice grains. This fraction is smaller than the within-hydrometeor deposition fraction because meltwater flux preferentially removes internal BC, while sublimation and freezing within snowpack expose internal BC. Incorporating the DEMA into a global climate model, we simulate increases in BC/snow radiative forcing of 43–86%, relative to scenarios that apply external optical properties to all BC. We

  15. Enhanced Solar Energy Absorption by Internally-mixed Black Carbon in Snow Grains

    Energy Technology Data Exchange (ETDEWEB)

    Flanner, M. G.; Liu, Xiaohong; Zhou, Cheng; Penner, Joyce E.; Jiao, C.

    2012-05-30

    Here we explore light absorption by snowpack containing black carbon (BC) particles residing within ice grains. Basic considerations of particle volumes and BC/snow mass concentrations show that there are generally 0:05-109 BC particles for each ice grain. This suggests that internal BC is likely distributed as multiple inclusions within ice grains, and thus the dynamic effective medium approximation (DEMA) (Chylek and Srivastava, 1983) is a more appropriate optical representation for BC/ice composites than coated-sphere or standard mixing approximations. DEMA calculations show that the 460 nm absorption cross-section of BC/ice composites, normalized to the mass of BC, is typically enhanced by factors of 1.8-2.1 relative to interstitial BC. BC effective radius is the dominant cause of variation in this enhancement, compared with ice grain size and BC volume fraction. We apply two atmospheric aerosol models that simulate interstitial and within-hydrometeor BC lifecycles. Although only {approx}2% of the atmospheric BC burden is cloud-borne, 71-83% of the BC deposited to global snow and sea-ice surfaces occurs within hydrometeors. Key processes responsible for within-snow BC deposition are development of hydrophilic coatings on BC, activation of liquid droplets, and subsequent snow formation through riming or ice nucleation by other species and aggregation/accretion of ice particles. Applying deposition fields from these aerosol models in offline snow and sea-ice simulations, we calculate that 32-73% of BC in global surface snow resides within ice grains. This fraction is smaller than the within-hydrometeor deposition fraction because meltwater flux preferentially removes internal BC, while sublimation and freezing within snowpack expose internal BC. Incorporating the DEMA into a global climate model, we simulate increases in BC/snow radiative forcing of 43-86%, relative to scenarios that apply external optical properties to all BC. We show that snow metamorphism

  16. Decomposing the impact of alternative technology sets on future carbon emissions growth

    International Nuclear Information System (INIS)

    Fisher-Vanden, Karen; Schu, Kathryn; Sue Wing, Ian; Calvin, Katherine

    2012-01-01

    What are the drivers of future global carbon dioxide (CO 2 ) emissions growth and how would the availability of key energy supply technologies change their relative importance? In this paper, we apply a novel index number decomposition technique to the results of a multi-region, multi-sector computable general equilibrium model to quantify the influence of five factors on the growth of future carbon emissions: (1) growth in global economic activity; (2) shifts in the regional composition of gross world product; (3) shifts in the sectoral composition of regions' GDP; (4) changes in sectors' energy–output ratios; and (5) changes in the CO 2 intensity of energy sources. We elucidate how the relative importance of these factors changes in response to the imposition of a global carbon tax and alternative assumptions about the future availability of key energy supply technologies. Rising global economic activity and shifts in regional composition put upward pressure on emissions while changes in energy and emission intensity and the sectoral output mix have attenuating effects. A global emission tax that increases over time slows economic expansion and shifts the fuel mix, with the most pronounced impacts on China, India, and Russia. Limited availability of carbon capture and storage, nuclear, and hydroelectric generation all lead to upward shifts in the long-run marginal abatement cost curve, causing some countries to choose to pay the tax rather than abate. - Highlights: ► Index number decomposition is used to quantify the influence of five factors. ► The relative importance of these factors in response to alternative assumptions is measured. ► A global emission tax that increases over time slows economic expansion and shifts the fuel mix. ► Limited technology availability mean some countries to choose to pay the tax rather than abate.

  17. Microfabricated photoplastic cantilever with integrated photoplastic/carbon based piezoresistive strain sensor

    DEFF Research Database (Denmark)

    Gammelgaard, Lauge; Rasmussen, Peter Andreas; Calleja, M.

    2006-01-01

    We present an SU-8 micrometer sized cantilever strain sensor with an integrated piezoresistor made of a conductive composite of SU-8 polymer and carbon black particles. The composite has been developed using ultrasonic mixing. Cleanroom processing of the polymer composite has been investigated...

  18. Carbon leaching from tropical peat soils and consequences for carbon balances

    Directory of Open Access Journals (Sweden)

    Tim Rixen

    2016-07-01

    Full Text Available Drainage and deforestation turned Southeast (SE Asian peat soils into a globally important CO2 source, because both processes accelerate peat decomposition. Carbon losses through soil leaching have so far not been quantified and the underlying processes have hardly been studied. In this study, we use results derived from nine expeditions to six Sumatran rivers and a mixing model to determine leaching processes in tropical peat soils, which are heavily disturbed by drainage and deforestation. Here we show that a reduced evapotranspiration and the resulting increased freshwater discharge in addition to the supply of labile leaf litter produced by re-growing secondary forests increase leaching of carbon by ~200%. Enhanced freshwater fluxes and leaching of labile leaf litter from secondary vegetation appear to contribute 38% and 62% to the total increase, respectively. Decomposition of leached labile DOC can lead to hypoxic conditions in rivers draining disturbed peatlands. Leaching of the more refractory DOC from peat is an irrecoverable loss of soil that threatens the stability of peat-fringed coasts in SE Asia.

  19. Bimaximal fermion mixing from the quark and leptonic mixing matrices

    International Nuclear Information System (INIS)

    Ohlsson, Tommy

    2005-01-01

    In this Letter, we show how the mixing angles of the standard parameterization add when multiplying the quark and leptonic mixing matrices, i.e., we derive explicit sum rules for the quark and leptonic mixing angles. In this connection, we also discuss other recently proposed sum rules for the mixing angles assuming bimaximal fermion mixing. In addition, we find that the present experimental and phenomenological data of the mixing angles naturally fulfill our sum rules, and thus, give rise to bilarge or bimaximal fermion mixing

  20. Trends and Issues in California's Low Carbon Fuel Standard - Learning from Response to Existing Climate Policy

    Science.gov (United States)

    Witcover, J.

    2015-12-01

    Debate over lower greenhouse gas (GHG) emissions from transportation has included heated discussion about appropriate policies and their cost and feasibility. One prominent policy mechanism, a carbon intensity standard, rates transport fuels based on analysis of lifecycle GHG emissions, and targets lower fuel pool carbon intensity through a market mechanism that uses a system of tradable, bankable credits and deficits. California instituted such a policy -- the Low Carbon Fuel Standard (LCFS) - in 2010, which targets a 10% carbon intensity (CI) reduction by 2020. The program rolled out amid concerns over slow development of new fuels expected to be very low carbon (such as cellulosic) and has faced court challenges that added considerable policy uncertainty. Since the program's start, state transport energy mix has shifted modestly but noticeably. Looking ahead, emerging issues for the program include amendments and re-adoption in response to a court ruling, potential interaction with California's multi-sector cap on carbon emissions (which started covering transport fuels in 2015), and impacts from similar CI standards in other jurisdictions. This study provides an analysis of fuel mix changes since the LCFS was implemented in 2011, and a discussion of emerging issues focusing on policy interaction. Descriptive statistics on alternative fuel use, available fuel pathways, and CI ratings are presented based on data from the California Air Resources Board (which runs the program). They document a shift towards more alternative fuels in a more diverse mix, with lower average CI ratings for most alternative fuel types. Financial incentives for various fuels are compared under the LCFS and the US federal Renewable Fuel Standard; disincentives from conceptually different carbon pricing schemes under the LCFS and the Cap-and-Trade are also outlined. The results provide important information on response to an existing market-based policy mechanism for addressing GHG

  1. Drivers of the Seasonal Carbon Cycle in the Coastal Gulf of Alaska

    Science.gov (United States)

    Pilcher, D.; Siedlecki, S. A.; Hermann, A. J.; Coyle, K. O.; Mathis, J. T.

    2016-02-01

    The Coastal Gulf of Alaska serves as a significant carbon sink annually, but varies seasonally from net carbon efflux in winter, to net carbon uptake from spring through fall. This significant uptake of anthropogenic CO2 combined with the naturally cold, low calcium carbonate surface waters is expected to accelerate ocean acidification. Observational evidence has already detected subsurface aragonite undersaturation, likely resulting from carbon remineralization of sinking organic matter. Other processes such as storm-induced vertical mixing, glacial runoff, temperature change, and nutrient supply can further modify the carbon cycle. Improving knowledge of these seasonal processes is critical for the region's fisheries that provide substantial ecosystem services and can be adversely impacted by sub-optimal aragonite saturation conditions. We use a regional model of the Coastal Gulf of Alaska coupled to an ecosystem model with full carbonate chemistry to investigate the physical and biogeochemical mechanisms that drive the seasonal carbon cycle. Boundary conditions are set from the coarser Northeast Pacific model, with alkalinity and carbon concentrations determined from empirical relationships with salinity. Model output from a 2009 hindcast simulation is compared to observations of alkalinity and dissolved inorganic carbon concentrations for model verification and to elucidate seasonal mechanisms.

  2. Determination of Carbon-14 in environmental samples by mixing 14CO2 with a liquid scintillator

    International Nuclear Information System (INIS)

    Garcia, M. R.; Gomez, V.; Heras, M. C.; Beltran, M. A.

    1990-01-01

    A method for the determination of Carbon-14 (14CO2) in environmental samples has been developed. The method use the direct absorption of the carbon dioxide into Carbosorb, followed with incorporation of the mixture (Carbosorb-CO2) to the liquid scintillator. The results obtained to apply this method and the benzene synthesis, usual in our laboratory, are discussed and compared. The method of collection of atmospheric samples is also described. (Author) 10 refs

  3. RESTORING SUSTAINABLE FORESTS ON APPALACHIAN MINED LANDS FOR WOOD PRODUCTS, RENEWABLE ENERGY, CARBON SEQUESTRATION, AND OTHER ECOSYSTEM SERVICES

    Energy Technology Data Exchange (ETDEWEB)

    J. Burger; J. Galbraith; T. Fox; G. Amacher; J. Sullivan; C. Zipper

    2003-12-18

    The overall purpose of this project is to evaluate the biological and economic feasibility of restoring high-quality forests on mined land, and to measure carbon sequestration and wood production benefits that would be achieved from forest restoration procedures. In this quarterly report, we present a preliminary comparison of the carbon sequestration benefits for two forest types used to convert abandoned grasslands for carbon sequestration. Annual mixed hardwood benefits, based on total stand carbon volume present at the end of a given year, range from a minimum of $0/ton of carbon to a maximum of $5.26/ton of carbon (low prices). White pine benefits based on carbon volume range from a minimum of $0/ton of carbon to a maximum of $18.61/ton of carbon (high prices). The higher maximum white pine carbon payment can primarily be attributed to the fact that the shorter rotation means that payments for white pine carbon are being made on far less cumulative carbon tonnage than for that of the long-rotation hardwoods. Therefore, the payment per ton of white pine carbon needs to be higher than that of the hardwoods in order to render the conversion to white pine profitable by the end of a rotation. These carbon payments may seem appealingly low to the incentive provider. However, payments (not discounted) made over a full rotation may add up to approximately $17,493/ha for white pine (30-year rotation), and $18,820/ha for mixed hardwoods (60-year rotation). The literature suggests a range of carbon sequestration costs, from $0/ton of carbon to $120/ton of carbon, although the majority of studies suggest a cost below $50/ ton of carbon, with van Kooten et al. (2000) suggesting a cutoff cost of $20/ton of carbon sequestered. Thus, the ranges of carbon payments estimated for this study fall well within the ranges of carbon sequestration costs estimated in previous studies.

  4. Proximal sensing for soil carbon accounting

    OpenAIRE

    England, Jacqueline R.; Viscarra Rossel, Raphael A.

    2018-01-01

    Maintaining or increasing soil organic carbon (C) is vital for securing food production and for mitigating greenhouse gas (GHG) emissions, climate change, and land degradation. Some land management practices in cropping, grazing, horticultural, and mixed farming systems can be used to increase organic C in soil, but to assess their effectiveness, we need accurate and cost-efficient methods for measuring and monitoring the change. To determine the stock of organic C in soil, one requires...

  5. When should green technology support policies supplement the carbon price? The case of the electricity sector

    International Nuclear Information System (INIS)

    Lecuyer, Oskar

    2013-01-01

    This thesis contributes to the literature on optimal policy choice. It studies the use of policy combinations to mitigate greenhouse gases emissions from electricity production. One finding applies to cases where uncertainty is such that the risk of a nil carbon price cannot be excluded. A cap on emissions alone may then not trigger enough abatements, justifying the addition of e.g. a renewable subsidy. When considering a transition toward a carbon free electricity sector, capital accumulation causes complex dynamic effects to happen. We find that decisions taken by comparing the leveled costs of abatement technologies, even including carbon costs, would favor intermediate technologies (e.g. gas plants) to the detriment of more-expensive but lower-carbon technologies (renewable power), leading to a suboptimal investment schedule. This thesis also studies the effects of marginal policy changes in a mix comprising the main French instruments. We find that surprisingly, adding a tariff for renewables financed by a tax on electricity consumption to a cap on emissions and a subsidy for energy efficiency will reduce the consumer electricity price when the non-renewable production is fixed and does not depend on the carbon price. The assessment of the French climate policies in the electricity sector shows that overlapping policies for mitigation may be justified by multiple carbon price failures, even if the ideal long-term policy mix depends on the carbon price trajectory. (author)

  6. Electrolyte matrix for molten carbonate fuel cells

    Science.gov (United States)

    Huang, C.M.; Yuh, C.Y.

    1999-02-09

    A matrix is described for a carbonate electrolyte including a support material and an additive constituent having a relatively low melting temperature and a relatively high coefficient of thermal expansion. The additive constituent is from 3 to 45 weight percent of the matrix and is formed from raw particles whose diameter is in a range of 0.1 {micro}m to 20 {micro}m and whose aspect ratio is in a range of 1 to 50. High energy intensive milling is used to mix the support material and additive constituent during matrix formation. Also disclosed is the use of a further additive constituent comprising an alkaline earth containing material. The further additive is mixed with the support material using high energy intensive milling. 5 figs.

  7. Electrolyte matrix for molten carbonate fuel cells

    Science.gov (United States)

    Huang, Chao M.; Yuh, Chao-Yi

    1999-01-01

    A matrix for a carbonate electrolyte including a support material and an additive constituent having a relatively low melting temperature and a relatively high coefficient of thermal expansion. The additive constituent is from 3 to 45 weight percent of the matrix and is formed from raw particles whose diameter is in a range of 0.1 .mu.m to 20 .mu.m and whose aspect ratio is in a range of 1 to 50. High energy intensive milling is used to mix the support material and additive constituent during matrix formation. Also disclosed is the use of a further additive constituent comprising an alkaline earth containing material. The further additive is mixed with the support material using high energy intensive milling.

  8. Carbon flow electrodes for continuous operation of capacitive deionization and capacitive mixing energy generation

    NARCIS (Netherlands)

    Porada, S.; Hamelers, H.V.M.; Bryjak, M.; Presser, V.; Biesheuvel, P.M.; Weingarth, D.

    2014-01-01

    Capacitive technologies, such as capacitive deionization and energy harvesting based on mixing energy (“capmix” and “CO2 energy”), are characterized by intermittent operation: phases of ion electrosorption from the water are followed by system regeneration. From a system application point of view,

  9. Fabrication and electrochemical behavior of single-walled carbon nanotube/graphite-based electrode

    International Nuclear Information System (INIS)

    Moghaddam, Abdolmajid Bayandori; Ganjali, Mohammad Reza; Dinarvand, Rassoul; Razavi, Taherehsadat; Riahi, Siavash; Rezaei-Zarchi, Saeed; Norouzi, Parviz

    2009-01-01

    An electrochemical method for determining the dihydroxybenzene derivatives on glassy carbon (GC) has been developed. In this method, the performance of a single-walled carbon nanotube (SWCNT)/graphite-based electrode, prepared by mixing SWCNTs and graphite powder, was described. The resulting electrode shows an excellent behavior for redox of 3,4-dihydroxybenzoic acid (DBA). SWCNT/graphite-based electrode presents a significant decrease in the overvoltage for DBA oxidation as well as a dramatic improvement in the reversibility of DBA redox behavior in comparison with graphite-based and glassy carbon (GC) electrodes. In addition, scanning electron microscopy (SEM) and atomic force microscopy (AFM) procedures performed for used SWCNTs

  10. Cathodic electrodeposition of mixed molybdenum tungsten oxides from peroxo-polymolybdotungstate solutions.

    Science.gov (United States)

    Kondrachova, Lilia; Hahn, Benjamin P; Vijayaraghavan, Ganesh; Williams, Ryan D; Stevenson, Keith J

    2006-12-05

    Mixed molybdenum tungsten trioxide films of varying stoichiometry (MoxW1 - xO3, 0 cathodic electrodeposition on indium tin oxide (ITO)-coated glass substrates from aqueous peroxo-polymolybdotungstate solutions. Electrochemical quartz crystal microbalance (EQCM), cyclic voltammetry, and chronocoulometry were used to gain insight into the electrodeposition mechanism. The compositional and structural properties were characterized for MoxW1 - xO3 films deposited at intermediate potentials (-0.35 V vs Ag/AgCl) and sintered at 250 degrees C using energy-dispersive spectroscopy, X-ray diffraction, and Raman spectroscopy. These studies reveal that films consist of homogeneously mixed MoxW1 - xO3, with an enriched Mo content ranging in composition from 0.4 < x < 0.7 depending upon the mol % Mo present in the deposition solution. Chronoamperometry and spectroelectrochemical measurements were conducted to estimate lithium ion diffusion coefficients and coloration efficiencies for the mixed metal oxide films in 1 M LiClO4/propylene carbonate. The subtle interplay between structural and compositional properties due to the uniform mixing of Mo and W oxide components shows that electrochromic and lithium ion transport properties are moderately enhanced relative to those of single-component WO3 and MoO3 and demonstrate improved structural stability over pure MoO3 polymorphs during electrochemical cycling.

  11. Ecodynamics of oil-degrading bacteria and significance of marine mixed populations in the degradation of petroleum compounds

    International Nuclear Information System (INIS)

    Venkateswaran, Kasthuri; Tanaka, Hiroki; Komukai, Shyoko

    1993-01-01

    Ecological studies, screening of hydrocarbon-degrading bacteria, and studies of the potentials of various single and mixed bacterial populations in the utilization of petroleum compounds were carried out to understand the microbial hydrocarbon degradation process in marine ecosystems. Populations of hydrocarbon utilizers were larger in coastal regions than in pelagic environments. Ecological observations indicated that oil-degrading bacteria were ubiquitously distributed in both temperate and tropical environments, irrespective of oil-polluted and unpolluted ecosystem. Bacteria were grown with n-tet-radecane, pristane, propylbenzene, phenanthrene, and crude oil as the sole carbon source; and substrate specificities of the purified strains were characterized. Based on the assimilation characteristics of the isolated strains, an artificial mixed-culture system was constructed. Biodegradation of crude oil by the natural mixed population was found to be higher than by the artificial mixed population. However, when some of the substrate-specific degraders were artificially mixed with natural microflora, the degradation of hard-to-degrade aromatic hydrocarbon fractions of crude oil was enhanced

  12. Multi Objective Optimization of Multi Wall Carbon Nanotube Based Nanogrinding Wheel Using Grey Relational and Regression Analysis

    Science.gov (United States)

    Sethuramalingam, Prabhu; Vinayagam, Babu Kupusamy

    2016-07-01

    Carbon nanotube mixed grinding wheel is used in the grinding process to analyze the surface characteristics of AISI D2 tool steel material. Till now no work has been carried out using carbon nanotube based grinding wheel. Carbon nanotube based grinding wheel has excellent thermal conductivity and good mechanical properties which are used to improve the surface finish of the workpiece. In the present study, the multi response optimization of process parameters like surface roughness and metal removal rate of grinding process of single wall carbon nanotube (CNT) in mixed cutting fluids is undertaken using orthogonal array with grey relational analysis. Experiments are performed with designated grinding conditions obtained using the L9 orthogonal array. Based on the results of the grey relational analysis, a set of optimum grinding parameters is obtained. Using the analysis of variance approach the significant machining parameters are found. Empirical model for the prediction of output parameters has been developed using regression analysis and the results are compared empirically, for conditions of with and without CNT grinding wheel in grinding process.

  13. Selective Oxidation of Soft Grade Carbon

    Directory of Open Access Journals (Sweden)

    Zecevic, N.

    2007-12-01

    the surface area is essential. Mutual oxidizing agents are ozone, air, mixture of nitric oxide and air, and nitric acid. However, treatment with highly oxidizing agents in a gaseous phase or aqueous medium may highly increase the concentration of acid oxides on the surface area of the carbon black. Acid oxides on the surface area of carbon black decrease the pH value, which is closely connected to the vulcanization of rubber compounds. Furthermore, the afore-mentioned method has other disadvantages. In the case of nitrate acid, the major disadvantage is corrosion of plant equipment. The mixture of nitrite oxide and air demands a very complicated plant, and the same procedure is very time consuming. Ozone increases the oxygen content on the surface area of the carbon black by as much as 15 %, which creates carbon dioxide and reduces utilization. Air creates thermally unstable surface area oxides, since the process demands a temperature range between 450 and 700 °C. Due to all these reasons, an oxidation method was developed of eliminating non-reacted oil from the surface area of oil-furnace carbon black, which cannot be produced with the conventional production method. An aqueous solution of salt ammonium nitrate p.a. proved to be a very good oxidizing agent. Conventional soft grades of oil-furnace carbon blacks with very high contents of non-reacted oil on their surface area, were mixed with the appropriate mass weight of ammonium nitrate p. a. (1.25 to 10.00 g L-1 NH4NO3 p. a.. The obtained homogeneous mixture was dried at temperatures from 180 to 210 °C for a period of 30 to 120 min. Namely, oil-furnace carbon blacks are first produced in a "fluffy" form with exceptionally small mass density, which is why they are very unpractical for manipulation. The "fluffy" oil-furnace carbon black must be transformed to a greater weight density and have a smaller quantity of fines as possible. However, there are many industrial processes of transforming "fluffy" carbon black

  14. B33C-0612: Evaluation of Simulated Biospheric Carbon Dioxide Fluxes and Atmospheric Concentrations Using Global in Situ Observations

    Science.gov (United States)

    Philip, Sajeev; Johnson, Matthew S.; Potter, Christopher S.; Genovese, Vanessa

    2016-01-01

    Atmospheric mixing ratios of carbon dioxide (CO2) are largely controlled by anthropogenic emission sources and biospheric sources/sinks. Global biospheric fluxes of CO2 are controlled by complex processes facilitating the exchange of carbon between terrestrial ecosystems and the atmosphere. These processes which play a key role in these terrestrial ecosystem-atmosphere carbon exchanges are currently not fully understood, resulting in large uncertainties in the quantification of biospheric CO2 fluxes. Current models with these inherent deficiencies have difficulties simulating the global carbon cycle with high accuracy. We are developing a new modeling platform, GEOS-Chem-CASA by integrating the year-specific NASA-CASA (National Aeronautics and Space Administration - Carnegie Ames Stanford Approach) biosphere model with the GEOS-Chem (Goddard Earth Observation System-Chemistry) chemical transport model to improve the simulation of atmosphere-terrestrial ecosystem carbon exchange. We use NASA-CASA to explicitly represent the exchange of CO2 between terrestrial ecosystem and atmosphere by replacing the baseline GEOS-Chem land net CO2 flux and forest biomass burning CO2 emissions. We will present the estimation and evaluation of these "bottom-up" land CO2 fluxes, simulated atmospheric mixing ratios, and forest disturbance changes over the last decade. In addition, we will present our initial comparison of atmospheric column-mean dry air mole fraction of CO2 predicted by the model and those retrieved from NASA's OCO-2 (Orbiting Carbon Observatory-2) satellite instrument and model-predicted surface CO2 mixing ratios with global in situ observations. This evaluation is the first step necessary for our future work planned to constrain the estimates of biospheric carbon fluxes through "top-down" inverse modeling, which will improve our understanding of the processes controlling atmosphere-terrestrial ecosystem greenhouse gas exchanges, especially over regions which lack in

  15. Subseafloor fluid mixing and fossilized microbial life in a Cretaceous 'Lost City'-type hydrothermal system at the Iberian Margin

    Science.gov (United States)

    Klein, F.; Humphris, S. E.; Guo, W.; Schubotz, F.; Schwarzenbach, E. M.; Orsi, W.

    2015-12-01

    Subseafloor mixing of reduced hydrothermal fluids with seawater is believed to provide the energy and substrates needed to support autotrophic microorganisms in the hydrated oceanic mantle (serpentinite). Despite the potentially significant implications for the distribution of microbial life on Earth and other water-bearing planetary bodies, our understanding of such environments remains elusive. In the present study we examined fossilized microbial communities and fluid mixing processes in the subseafloor of a Cretaceous 'Lost City'-type hydrothermal system at the passive Iberia Margin (ODP Leg 149, Hole 897D). Brucite and calcite co-precipitated from mixed fluids ca. 65m below the Cretaceous palaeo-seafloor at temperatures of 32±4°C within steep chemical gradients (fO2, pH, CH4, SO4, ΣCO2, etc) between weathered, carbonate-rich serpentinite breccia and serpentinite. Mixing of oxidized seawater and strongly reducing hydrothermal fluid at moderate temperatures created conditions capable of supporting microbial activity within the oceanic basement. Dense microbial colonies are fossilized in brucite-calcite veins that are strongly enriched in organic carbon but depleted in 13C. We detected a combination of bacterial diether lipid biomarkers, archaeol and archaeal tetraethers analogous to those found in brucite-carbonate chimneys at the active Lost City hydrothermal field. The exposure of mantle rocks to seawater during the breakup of Pangaea fueled chemolithoautotrophic microbial communities at the Iberia Margin during the Cretaceous, possibly before the onset of seafloor spreading in the Atlantic. 'Lost City'-type serpentinization systems have been discovered at mid-ocean ridges, in forearc settings of subduction zones and at continental margins. It appears that, wherever they occur, they can support microbial life, even in deep subseafloor environments as demonstrated in the present study. Because equivalent systems have likely existed throughout most of Earth

  16. Charaterising water-rock interaction in a mixed carbonate-evaporite karstified aquifer system, Qatar

    Science.gov (United States)

    Thirathititham, R.; Whitaker, F.

    2017-12-01

    Qatar is an arid country, most of the rainfall (80 mm/yr) occurring during intense storms. Surface runoff is endorheic and recharge is facilitated by karst features developed over an extended (c.30 Ma) period of exposure of the carbonate bedrock. In December 2016, we sampled a rare intense rainfall event (41 mm over 3 days), after which waters ponded within low-relief terminal depressions prior to infiltration. We compare the chemistry of these recharge waters with that of ground waters from 76 wells distributed across Qatar to understand the nature and spatial distribution of water-rock interaction. Using Cl- as a conservative tracer for seawater mixing, we calculate concentrations of rock-derived Ca2+, Mg2+ and SO42-. During surface detention, rain chemistry is modified by evaporation and interaction with clays and the surface bedrock over days to weeks. However, groundwater chemistry is dominated by subsurface interaction between recharge waters and the karstified Tertiary aquifers. These include the largely dolomitic Paleocene to Lower Eocene Umm er Radhuma (UER) and overlying Lower Eocene Rus, with the Middle Eocene Abarug limestone forming a locally important aquifer in the south west. Away from coastal areas which show clear evidence of salinisation, TDS of groundwaters in the interior of the peninsula increases from north to south. All groundwaters are significantly enriched in SO42-, but this enrichment is marked greater in the south. This likely reflects the presence of a unit of middle Rus gypsum that in the south of the country confines the Lower Rus and UER aquifers, whilst in the north either gypsum was not deposited or has been dissolved. Waters in the Abarug limestone show limited sulfate enrichment and a 1:1 molar ratio of rock-derived SO42-: Ca2+, but across much of the country both SO42- enrichment and SO42-: Ca2+ molar ratio are significantly higher, the latter reaching 2:1 and suggesting an additional sink for Ca2+. The dolomite aquifer waters

  17. European mixed forests

    DEFF Research Database (Denmark)

    Bravo-Oviedo, Andres; Pretzsch, Hans; Ammer, Christian

    2014-01-01

    Aim of study: We aim at (i) developing a reference definition of mixed forests in order to harmonize comparative research in mixed forests and (ii) review the research perspectives in mixed forests. Area of study: The definition is developed in Europe but can be tested worldwide. Material...... and Methods: Review of existent definitions of mixed forests based and literature review encompassing dynamics, management and economic valuation of mixed forests. Main results: A mixed forest is defined as a forest unit, excluding linear formations, where at least two tree species coexist at any...... density in mixed forests, (iii) conversion of monocultures to mixed-species forest and (iv) economic valuation of ecosystem services provided by mixed forests. Research highlights: The definition is considered a high-level one which encompasses previous attempts to define mixed forests. Current fields...

  18. Comparative Study on the Solid Electrolyte Interface Formation by the Reduction of Alkyl Carbonates in Lithium ion Battery

    International Nuclear Information System (INIS)

    Haregewoin, Atetegeb Meazah; Leggesse, Ermias Girma; Jiang, Jyh-Chiang; Wang, Fu-Ming; Hwang, Bing-Joe; Lin, Shawn D.

    2014-01-01

    Mixed alkyl carbonates are widely used as solvent for a various lithium-ion battery applications. Understanding the behavior of each solvent in the mixed system is crucial for controlling the electrolyte composition. In this paper, we report a systematic electrochemical and spectroscopic comparison of the reduction of propylene carbonate (PC), ethylene carbonate (EC), and diethyl carbonate (DEC) when used as single (PC), binary (EC/PC, EC/DEC), and ternary (EC/PC/DEC) solvent systems. The reduction products are identified based on Fourier transform infrared spectroscopy (FTIR) after employing linear sweep voltammetry to certain potential regions and their possible formation mechanisms are discussed. FTIR analyses revealed that the reduction of EC and PC was not considerably influenced by the presence of other alkyl carbonates. However, DEC exhibited a different reduction product when used in EC/DEC and EC/PC/DEC solvent systems. The reduction of EC occurred before that of PC and DEC and produced a passivating surface film that prevented carbon exfoliation caused by PC. Battery performance test, cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscope is employed to study the surface films formed. The binary EC/DEC solvent system demonstrated more favorable performance, smaller impedance, and higher Li + ion diffusivity than did the other solvent systems used in this study

  19. Iron-carbonate interaction at Earth's core-mantle boundary

    Science.gov (United States)

    Dorfman, S. M.; Badro, J.; Nabiei, F.; Prakapenka, V.; Gillet, P.

    2015-12-01

    Carbon storage and flux in the deep Earth are moderated by oxygen fugacity and interactions with iron-bearing phases. The amount of carbon stored in Earth's mantle versus the core depends on carbon-iron chemistry at the core-mantle boundary. Oxidized carbonates subducted from Earth's surface to the lowermost mantle may encounter reduced Fe0 metal from disproportionation of Fe2+ in lower mantle silicates or mixing with the core. To understand the fate of carbonates in the lowermost mantle, we have performed experiments on sandwiches of single-crystal (Ca0.6Mg0.4)CO3 dolomite and Fe foil in the laser-heated diamond anvil cell at lower mantle conditions of 49-110 GPa and 1800-2500 K. Syntheses were conducted with in situ synchrotron X-ray diffraction to identify phase assemblages. After quench to ambient conditions, samples were sectioned with a focused Ga+ ion beam for composition analysis with transmission electron microscopy. At the centers of the heated spots, iron melted and reacted completely with the carbonate to form magnesiowüstite, iron carbide, diamond, magnesium-rich carbonate and calcium carbonate. In samples heated at 49 and 64 GPa, the two carbonates exhibit a eutectoid texture. In the sample heated at 110 GPa, the carbonates form rounded ~150-nm-diameter grains with a higher modal proportion of interspersed diamonds. The presence of reduced iron in the deep lower mantle and core-mantle boundary region will promote the formation of diamonds in carbonate-bearing subducted slabs. The complete reaction of metallic iron to oxides and carbides in the presence of mantle carbonate supports the formation of these phases at the Earth's core-mantle boundary and in ultra-low velocity zones.

  20. Vaginal Calculus in a Woman With Mixed Urinary Incontinence and Vaginal Mesh Exposure.

    Science.gov (United States)

    Winkelman, William D; Rabban, Joseph T; Korn, Abner P

    2016-01-01

    Vaginal calculi are extremely rare and are most commonly encountered in the setting of an urethrovaginal or vesicovaginal fistula. We present a case of a 72-year-old woman with mixed urinary incontinence and vaginal mesh exposure incidentally found to have a large vaginal calculus. We removed the calculus surgically and analyzed the components. Results demonstrated the presence of ammonium-magnesium phosphate hexahydrate and carbonate apatite.

  1. [Characteristics of carbon storage of Inner Mongolia forests: a review].

    Science.gov (United States)

    Yang, Hao; Hu, Zhong-Min; Zhang, Lei-Ming; Li, Sheng-Gong

    2014-11-01

    Forests in Inner Mongolia account for an important part of the forests in China in terms of their large area and high living standing volume. This study reported carbon storage, carbon density, carbon sequestration rate and carbon sequestration potential of forest ecosystems in Inner Mongolia using the biomass carbon data from the related literature. Through analyzing the data of forest inventory and the generalized allometric equations between volume and biomass, previous studies had reported that biomass carbon storage of the forests in Inner Mongolia was about 920 Tg C, which was 12 percent of the national forest carbon storage, the annual average growth rate was about 1.4%, and the average of carbon density was about 43 t · hm(-2). Carbon storage and carbon density showed an increasing trend over time. Coniferous and broad-leaved mixed forest, Pinus sylvestris var. mongolica forest and Betula platyphylla forest had higher carbon sequestration capacities. Carbon storage was reduced due to human activities such as thinning and clear cutting. There were few studies on carbon storage of the forests in Inner Mongolia with focus on the soil, showing that the soil car- bon density increased with the stand age. Study on the carbon sequestration potential of forest ecosystems was still less. Further study was required to examine dynamics of carbon storage in forest ecosystems in Inner Mongolia, i. e., to assess carbon storage in the forest soils together with biomass carbon storage, to compute biomass carbon content of species organs as 45% in the allometric equations, to build more species-specific and site-specific allometric equations including root biomass for different dominant species, and to take into account the effects of climate change on carbon sequestration rate and carbon sequestration potential.

  2. Grasland Stable Isotope Flux Measurements: Three Isotopomers of Carbon Dioxide Measured by QCL Spectroscopy

    Science.gov (United States)

    Zeeman, M. J.; Tuzson, B.; Eugster, W.; Werner, R. A.; Buchmann, N.; Emmenegger, L.

    2007-12-01

    To improve our understanding of greenhouse gas dynamics of managed ecosystems such as grasslands, we not only need to investigate the effects of management (e.g., grass cuts) and weather events (e.g., rainy days) on carbon dioxide fluxes, but also need to increase the time resolution of our measurements. Thus, for the first time, we assessed respiration and assimilation fluxes with high time resolution (5Hz) stable isotope measurements at an intensively managed farmland in Switzerland (Chamau, 400m ASL). Two different methods were used to quantify fluxes of carbon dioxide and associated fluxes of stable carbon isotopes: (1) the flux gradient method, and (2) the eddy covariance method. During a week long intensive measurement campaign, we (1) measured mixing ratios of carbon dioxide isotopomers (12C16O2, 12C16O18O, 13C16O2) with a Quantum Cascade Laser (QCL, Aerodyne Inc.) spectroscope and (2) collected air samples for isotope analyses (13C/12C) and (18O/16O) of carbon dioxide by Isotope Ratio Mass Spectrometry (IRMS, Finnigan) every two hours, concurrently along a height profile (z = 0.05; 0.10; 0.31; 2.15m). In the following week, the QCL setup was used for closed-path eddy covariance flux measurement of the carbon dioxide isotopomers, with the air inlet located next to an open-path Infra Red Gas Analyzers (IRGA, LiCor 7500) used simultaneously for carbon dioxide measurements. During this second week, an area of grass inside the footprint was cut and harvested after several days. The first results of in-field continuous QCL measurements of carbon dioxide mixing ratios and their stable isotopic ratios show good agreement with IRGA measurements and isotope analysis of flask samples by IRMS. Thus, QCL spectroscopy is a very promising tool for stable isotope flux investigations.

  3. Research on ration selection of mixed absorbent solution for membrane air-conditioning system

    International Nuclear Information System (INIS)

    Li, Xiu-Wei; Zhang, Xiao-Song; Wang, Fang; Zhao, Xiao; Zhang, Zhuo

    2015-01-01

    Highlights: • We derive models of the membrane air-conditioning system with mixed absorbents. • We make analysis on system COP, cost-effectiveness and economy. • The paper provides a new method for ideal absorbent selection. • The solutes concentration of 50% achieves the best cost-effectiveness and the economy. - Abstract: Absorption air-conditioning system is a good alternative to vapor compression system for developing low carbon society. To improve the performance of the traditional absorption system, the membrane air-conditioning system is configured and its COP can reach as high as 6. Mixed absorbents are potential for cost reduction of the membrane system while maintaining a high COP. On the purpose of finding ideal mixed absorbent groups, this paper makes analysis on COP, cost-effectiveness and economy of the membrane system with mixed LiBr–CaCl 2 absorbent solution. The models of the system have been developed for the analysis. The results show the COP is higher for the absorbent groups with lower concentration of the total solute and higher concentration ratio of LiBr. It also reveals when the total solutes concentration is about 50%, it achieves the best cost-effectiveness and the economy. The process of the analysis provides a useful method for mixed absorbents selection

  4. Passivation condition of carbon steel in bentonite/sand mixture

    International Nuclear Information System (INIS)

    Taniguchi, Naoki; Kawakami, Susumu

    2002-03-01

    It is essential to understand the corrosion type of carbon steel under the repository conditions for the lifetime assessment of carbon steel overpack used for geological isolation of high-level radioactive waste. According to the previous study, carbon steel is hard to passivate in buffer material assuming a chemical condition range of groundwater in Japan. However, concrete support will be constructed around the overpack in the case of repository in the soft rock system and groundwater having a higher pH may infiltrate to buffer material. There is a possibility that the corrosion type of carbon steel will be influenced by the rise of the pH in groundwater. In this study, anodic polarization experiments were performed to understand the passivation condition of carbon steel in buffer material saturated with water contacted with concrete. An ordinary concrete an a low-alkalinity concrete were used in the experiment. The results of the experiments showed that the carbon steel can passivate under the condition that water having pH > 13 infiltrate to the buffer material assuming present property of buffer material. If the low-alkalinity concrete is selected as the support material, passivation can not occur on carbon steel overpack. The effect of the factors of buffer material such as dry density and mixing ratio of sand on the passivation of carbon steel was also studied. The results of the study showed that the present property of buffer material is enough to prevent passivation of carbon steel. (author)

  5. The politics of carbon taxation - how varieties of policy style matter

    DEFF Research Database (Denmark)

    Andersen, Mikael Skou

    2018-01-01

    that the share of fossil fuels in the energy mix defines the room for such taxes, nor does it point to a strong role for political partisanship. Rather, it is deep-seated patterns of national policy styles with neo-corporatist traits, providing a protective device for the open economies of small countries, which...... condition the introduction of carbon taxes. The associated routines of decision-making offer coordination mechanisms for proactive macroeconomic policies in which carbon taxation can find a place. Parliamentary democracies with proportional representation, as are common in the smaller countries, provide...... access to the government for political parties that pursue carbon taxation. These in turn sensitise larger political parties to climate concerns, as they benefit from institutionalised practices and routines for problem-solving and consensus-seeking. Carbon taxes tend to get more leeway in coordinated...

  6. The generation mix in the Spanish electric system: factors affecting its evolution

    International Nuclear Information System (INIS)

    Chiarri, A.

    2009-01-01

    Currently while dealing with the electricity generation mix issue, the three pillars it is based on must be considered: sustain ability, security of supply and economic competitiveness. The two main sustain ability challenges that directly affect the future generation mix for the next decade is the development of the renewable sources and the reduction of the greenhouse gas emissions. This will cause an important increase of renewable and that the electricity system should be prepared for other low-carbon technologies such as nuclear and carbon capture and storage applied to fossil fuel plants. Regarding the security of supply, there is an increasing need to improve it. This can be achieved mainly through two actions: increase the self-sufficiency in primary energy and/or improve the diversification of the primary energy sources and of the origin such sources. finally it is also important to achieve and efficient investment system. In order to attain this goal, there is a need for a stable regulatory framework that should be the base for a real price for electricity. In order to fulfill all these requirements there is a need to keep all the options open, and also, to prepare the system to face the changes that are on sight. (Author) 8 refs

  7. Double layer mixed matrix membrane adsorbers improving capacity and safety hemodialysis

    Science.gov (United States)

    Saiful; Borneman, Z.; Wessling, M.

    2018-05-01

    Double layer mixed matrix membranes adsorbers have been developed for blood toxin removal by embedding activated carbon into cellulose acetate macroporous membranes. The membranes are prepared by phase inversion method via water vapor induced phase separation followed by an immersion precipitation step. Double layer MMM consisting of an active support and a separating layer. The active support layer consists of activated carbon particles embedded in macroporous cellulose acetate; the separating layer consists of particle free cellulose acetate. The double layer membrane possess an open and interconnected macroporous structure with a high loading of activated carbon available for blood toxins removal. The MMM AC has a swelling degree of 6.5 %, porosity of 53 % and clean water flux of 800 Lm-2h-1bar-1. The prepared membranes show a high dynamic Creatinine (Crt) removal during hemodilysis process. The Crt removal by adsorption contributes to amore than 83 % of the total removal. The double layer adsorptive membrane proves hemodialysis membrane can integrated with adsorption, in which blood toxins are removed in one step.

  8. Fracture toughness and failure mechanism of high performance concrete incorporating carbon nanotubes

    Directory of Open Access Journals (Sweden)

    A. Khitab

    2017-10-01

    Full Text Available Cement and concrete composites are inherently brittle and exhibit very less tensile/flexural strength capacity as compared to their compressive strength. Use of thoroughly dispersed carbon nanotubes in the concrete matrix is one of the possible solution for enhancing mechanical properties in tension/flexure. In the present research work, small fractions of multiwall carbon nanotube (MWCNTs i.e. 0.05 and 0.10 wt% of cement have been integrated into the cement concrete to study their effect on the mechanical properties of the resultant concrete mixtures. The enhanced performance of the whole mix lies on a single point that MWCNTs must be thoroughly disperse in the mixture. Hence, special arrangement through usage of high energy sonication along with amended acrylic based polymer (performing as a surfactant was made to have a uniform dispersion of MWCNTs in the concrete mix. The testing of concrete samples includes i.e., flexure, splitting tensile and compressive strengths after 3, 7, 28 and 56 days of curing. After having comparison with the control mix cured for 28 days, it was observed that the addition of 0.05 wt% MWCNTs increased the splitting tensile strength by 20.58%, flexural strength by 26.29% and compressive strength by 15.60%. Through above results, which verify the increase in concrete mix strength after adding MWCNTs, these MWCNTs may be incorporated in the treatment of Nano/micro cracks completed through process of connecting, branching and pinning. Similarly, as proved in threepoint bending tests, MWCNTs also enhances the breaking strains as well as the fracture energy of the concrete mixes, besides, imparting increase to the strength. The investigations have shown that incorporating lesser amounts of MWCNTs i.e., 0.05 and 0.10 wt% of cement to the concrete mixes after insuring there complete dispersion, unusually improve their properties like mechanical strengths and fracture behavior

  9. Our energy future - creating a low carbon economy

    International Nuclear Information System (INIS)

    2003-01-01

    This White Paper sets out a long-term framework for addressing the threat of climate change and reduced UK oil, gas, and coal production. The challenges facing the UK are examined covering the levels of carbon dioxide in the atmosphere, rising temperatures, droughts and floods, the economic impact of cutting emissions, the shift from energy exporter to energy importer, and the need to update the UK's energy infrastructure. The goals of the new energy policy, the fuel mix, and stimulation of the growth in renewable energies are considered. The importance of a carbon emission trading scheme, maintaining the reliability of energy supplies, promotion of competitive energy markets, and ensuring every home is adequately and affordably heated is discussed

  10. Ion sensing properties of vanadium/tungsten mixed oxides

    International Nuclear Information System (INIS)

    Guidelli, Eder Jose; Guerra, Elidia Maria; Mulato, Marcelo

    2011-01-01

    Vanadium/tungsten mixed oxide (V 2 O 5 /WO 3 ) sensing membranes were deposited on glassy carbon substrates and used as the H + sensor of the extended gate field effect transistor (EGFET) device. X-ray diffractograms indicated a decrease of the interplanar spacing of V 2 O 5 after the insertion of WO 3 revealing that the lamellar structure is under compressive stress. The crystallinity increases with increasing WO 3 molar ratio. The film is not homogeneous, with more WO 3 material sitting at the surface. This influences the response of pH sensors using the EGFET configuration. The maximum sensitivity of 68 mV pH -1 was obtained for the sample with 5% WO 3 molar ratio. For higher WO 3 molar ratios, the behavior is not linear. It can be concluded that V 2 O 5 dominates for acidic solutions while WO 3 dominates for basic solutions. Therefore, the mixed oxide with low amount of WO 3 is the main candidate for further use as biosensor.

  11. Carbon Capture and Storage and Carbon Capture and Utilization: What Do They Offer to Indonesia?

    Energy Technology Data Exchange (ETDEWEB)

    Adisaputro, Didi, E-mail: didiadisaputro@gmail.com [Department of Chemical and Biological Engineering, University of Sheffield, Sheffield (United Kingdom); Department of Energy Security, Indonesian Defence University, Bogor (Indonesia); Saputra, Bastian [Department of Chemical and Biological Engineering, University of Sheffield, Sheffield (United Kingdom)

    2017-03-30

    Indonesia is a developing country with abundance resource of fossil fuel in the world, and this fossil fuel will remain as the main source of energy over the next few decades. However, the Indonesian Government has committed to reducing greenhouse gas emissions from fossil fuel consumption as an effort to mitigate climate change. In view of this, two possible energy scenarios are envisioned to honor this commitment: “business as usual” (BaU) and the National Energy Policy (NEP) scenario (National Energy Council, 2014). The NEP scenario reduces CO{sub 2} emissions by up to 26% through an improved energy mix, less reliance on carbon-based fuels, and the deployment of renewable energy sources from 2020 to 2050. However, these actions are considered insufficient to further reduce the CO{sub 2} emission target, leading to an initiative to implement carbon capture and storage (CCS) technology.

  12. Preparation of carbon black masterbatch for PET using polymeric dispersing agents

    Energy Technology Data Exchange (ETDEWEB)

    Oh, D.H. [Kyungpook National University, Taegu (Korea, Republic of); Lim, J.C. [Pukyong National University, Pusan (Korea, Republic of); Seo, K.H. [Yeungnam College of Science and Technology, Taegu (Korea, Republic of)

    1999-03-01

    Three kinds of copolyesters, dispersing agents, were synthesized from the polycondensation reaction of dimethylterephthalate (DMT), dimethylisophthalate (DMI), sebacic acid (SA), and 1,4-butanediol (BD). Carbon black masterbatches were prepared by mixing carbon black into the dispersing agents (1 : 1.3 weight ratio) in a Brabender Plasticorder Using single screw extruder, masterbatches were compounded with poly(ethylene terephthalate) in 3 wt% concentration and mechanical properties of the compounds were investigated Gel permeation chromatography data implied that thermal degradation of polymeric dispersing agents was not significant through dispersion. Capillary rheometer test showed that PBTI has the highest viscosity and shear sensitivity among the there dispersing agents. Volume resistivities of masterbatch and transmission electron micrographs showed that dispersity of carbon black was improved with increasing melt viscosity of dispersing agent. The ultimate performance and mechanical characteristics of carbon black filled PET compounds depended directly on dispersion quality of the carbon black in masterbatch. Mechanical properties of compounds were improved with increasing dispersity of carbon black and with increasing content of rigid aromatic group in the copolyester dispersing agent. 30 refs., 9 figs., 5 tabs.

  13. Low-mass stars with mass loss and low-luminosity carbon star formation

    International Nuclear Information System (INIS)

    Boothroyd, A.I.

    1987-01-01

    The effects of large carbon enrichments in static stellar envelopes were investigated, using new Los Alamos opacities (including low-temperature carbon and molecular opacities) and including carbon ionizations. To search for the production of low-mass,low-luminosity carbon stars, detailed stellar evolutionary computations were carried out for a grid of low-mass stars of two different metallicities. The stars were evolved from the main sequence through all intermediate stages and through helium-shell flashes on the asymptotic giant branch. The effects of the latest nuclear reaction rates, the new Los Alamos opacities, Reimers-type wind mass loss, and detailed treatment of convection and semi-convection were investigated. Two low-luminosity carbon stars were achieved, in excellent agreement with observations. Conditions favoring dredge-up (and thus carbon-star production) include a reasonably large convective mixing length, low metallicity, relatively large envelope mass, and high flash strength. Mass loss was of major importance, tending to oppose dredge-up; the total mass-loss amounts inferred from observations suffice to prevent formation of high-mass, high-luminosity carbon stars

  14. China's carbon mitigation strategies: Enough?

    International Nuclear Information System (INIS)

    Wang, Can; Lin, Jie; Cai, Wenjia; Liao, Hua

    2014-01-01

    As the largest CO 2 emitter in the world, China has made great achievements in carbon mitigation over the past eight years (2005–2013). Through a comprehensive and detailed overview of China's carbon mitigation strategies, this paper presents China's carbon mitigation achievements and strategies, including adjustment to the industrial structure, saving energy, optimizing energy structure, increasing forest carbon sinks, building foundational capacity, innovating technologies and practicing mitigation efforts in localities and sectors. Having been in place for some years already, the results of many of these measures and policies are now plateauing. China is facing challenges including inevitable emissions growth, shrinking of mitigation potential from technological progress, difficulty in further adjusting the industrial structure and economic development mode, continued dominance of coal in the energy mix, local governments’ reluctance to adopt measures to reduce carbon emissions, etc. Through policy diagnosis it is found that the root causes of these problems and challenges are the facts that policy-making is done primarily on the production side and there is an absence of co-benefits in the decision-making process. Therefore, it is recommended that translating mitigation targets to the consumption level and mainstreaming mitigations’ co-benefits into decision-making processes are needed to quickly enhance the results of mitigation work in China. - Highlights: • Key aspects of China's carbon mitigation strategies were outlined. • China's carbon mitigation achievements were summarized. • Challenges to meet further mitigation were investigated. • Strategic suggestions to quickly enhance China's mitigation ambition were given

  15. Secondary sulfate is internally mixed with sea spray aerosol and organic aerosol in the winter Arctic

    Science.gov (United States)

    Kirpes, Rachel M.; Bondy, Amy L.; Bonanno, Daniel; Moffet, Ryan C.; Wang, Bingbing; Laskin, Alexander; Ault, Andrew P.; Pratt, Kerri A.

    2018-03-01

    Few measurements of aerosol chemical composition have been made during the winter-spring transition (following polar sunrise) to constrain Arctic aerosol-cloud-climate feedbacks. Herein, we report the first measurements of individual particle chemical composition near Utqiaġvik (Barrow), Alaska, in winter (seven sample days in January and February 2014). Individual particles were analyzed by computer-controlled scanning electron microscopy with energy dispersive X-ray spectroscopy (CCSEM-EDX, 24 847 particles), Raman microspectroscopy (300 particles), and scanning transmission X-ray microscopy with near-edge X-ray absorption fine structure spectroscopy (STXM-NEXAFS, 290 particles). Sea spray aerosol (SSA) was observed in all samples, with fresh and aged SSA comprising 99 %, by number, of 2.5-7.5 µm diameter particles, 65-95 % from 0.5-2.5 µm, and 50-60 % from 0.1-0.5 µm, indicating SSA is the dominant contributor to accumulation and coarse-mode aerosol during the winter. The aged SSA particles were characterized by reduced chlorine content with 94 %, by number, internally mixed with secondary sulfate (39 %, by number, internally mixed with both nitrate and sulfate), indicative of multiphase aging reactions during transport. There was a large number fraction (40 % of 1.0-4.0 µm diameter particles) of aged SSA during periods when particles were transported from near Prudhoe Bay, consistent with pollutant emissions from the oil fields participating in atmospheric processing of aerosol particles. Organic carbon and sulfate particles were observed in all samples and comprised 40-50 %, by number, of 0.1-0.4 µm diameter particles, indicative of Arctic haze influence. Soot was internally mixed with organic and sulfate components. All sulfate was mixed with organic carbon or SSA particles. Therefore, aerosol sources in the Alaskan Arctic and resulting aerosol chemical mixing states need to be considered when predicting aerosol climate effects, particularly cloud

  16. Crystallization of carbonate hydroxyapatite in the presence of strontium ranelate

    Science.gov (United States)

    Izmailov, R. R.; Golovanova, O. A.

    2015-11-01

    The influence of strontium ranelate on the crystallization of carbonate hydroxyapatite from a prototype of synovial fluid of humans has been investigated. The synthesis products are studied by IR Fourier spectroscopy, X-ray diffraction, and differential thermal analysis. The amount of strontium in the samples is determined by atomic emission analysis. The sizes of crystallites in the synthesized phases are calculated from the Selyakov-Scherrer formula; the lattice parameters are also determined. The phases obtained are found to be species of calcium-deficient strontium-containing carbonate hydroxyapatite of mixed A and B types. Schemes of chemical reactions occurring during heat treatment are proposed.

  17. Determination of cholesterol, calcium carbonate and bilirubinate of gallstone

    International Nuclear Information System (INIS)

    Iqbal, Y.; Nazneen, B.I.

    2004-01-01

    Gallstones of seven patients were collected from different parts of North West Frontier and Punjab provinces. These stones were analyzed using Liebermann-Burchard method, estimation technique and Microlab-200 for cholesterol, calcium carbonate (CaCO/sub 3/) and bilirubinate respectively. The levels of cholesterol bilirubinate and CaCO/sub 3/ were found in the ranges of 50-81, 12-40 and 7-19% respectively. All of the stones were found to be mixed type stones that contain cholesterol, bilirubinate and calcium carbonate. The structures of the stones are also shown in the picture, which confirm our analysis data. Possible reasons, which cause formation of gallstones, are discussed in this paper. (author)

  18. Emission testing of jatropha and pongamia mixed bio diesel fuel in a diesel engine

    International Nuclear Information System (INIS)

    Ali, M.; Shaikh, A.A.

    2012-01-01

    The present investigation is based on the emission characteristics of mixed bio diesel fuel in a four stroke single cylinder compression ignition engine at constant speed. Refined oils of jatropha and pongamia are converted into bio diesel by acid catalyzed esterification and base catalyzed transesterification reactions. The jatropha and pongamia bio diesel were mixed in equal proportions with conventional mineral diesel fuel. Four samples of fuel were tested namely, diesel fuel, B10, B20 and B40. The emission analysis showed B20 mixed bio diesel fuel blend having better results as compared to other samples. There is 60% and 35% lower emission of carbon monoxide and in sulphur dioxide observed while consuming B20 blended fuel respectively. The test result showed NOx emissions were 10% higher from bio diesel fuel, as compared to conventional diesel fuel. However, these emissions may be reduced by EGR (Exhaust Gas Recirculation) technology. Present research also revealed that that B20 mixed bio diesel fuel can be used, without any modification in a CI engine. (author)

  19. Conversion of Syngas-Derived C2+ Mixed Oxygenates to C3-C5 Olefins over ZnxZryOz Mixed Oxides Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Colin D.; Lebarbier, Vanessa M.; Flake, Matthew D.; Ramasamy, Karthikeyan K.; Kovarik, Libor; Bowden, Mark E.; Onfroy, Thomas; Dagle, Robert A.

    2016-04-01

    In this study we report on a ZnxZryOz mixed oxide type catalyst capable of converting a syngas-derived C2+ mixed oxygenate feedstock to isobutene-rich olefins. Aqueous model feed comprising of ethanol, acetaldehyde, acetic acid, ethyl acetate, methanol, and propanol was used as representative liquid product derived from a Rh-based mixed oxygenate synthesis catalyst. Greater than 50% carbon yield to C3-C5 mixed olefins was demonstrated when operating at 400-450oC and 1 atm. In order to rationalize formation of the products observed feed components were individually evaluated. Major constituents of the feed mixture (ethanol, acetaldehyde, acetic acid, and ethyl acetate) were found to produce isobutene-rich olefins. C-C coupling was also demonstrated for propanol feedstock - a minor constituent of the mixed oxygenate feed - producing branched C6 olefins, revealing scalability to alcohols higher than ethanol following an analogous reaction pathway. Using ethanol and propanol feed mixtures, cross-coupling reactions produced mixtures of C4, C5, and C6 branched olefins. The presence of H2 in the feed was found to facilitate hydrogenation of the ketone intermediates, thus producing straight chain olefins as byproducts. While activity loss from coking is observed complete catalyst regeneration is achieved by employing mild oxidation. For conversion of the mixed oxygenate feed a Zr/Zn ratio of 2.5 and a reaction temperature of 450oC provides the best balance of stability, activity, and selectivity. X-ray diffraction and scanning transmission electron microscopy analysis reveals the presence of primarily cubic phase ZrO2 and a minor amount of the monoclinic phase, with ZnO being highly dispersed in the lattice. The presence of ZnO appears to stabilize the cubic phase resulting in less monoclinic phase as the ZnO concentration increases. Infrared spectroscopy shows the mixed oxide acid sites are characterized as primarily Lewis type acidity. The direct relationship between

  20. Phase behaviour for the (carbon dioxide + 2-phenoxyethyl acrylate) and (carbon dioxide + 2-phenoxyethyl methacrylate) systems at temperatures from (313.2 to 393.2) K and pressures from (5 to 31) MPa

    International Nuclear Information System (INIS)

    Byun, Hun-Soo; Jang, Yoon-Seok; Yoo, Ki-Pung

    2010-01-01

    The solubility curves for the (carbon dioxide + 2-phenoxyethyl acrylate) and (carbon dioxide + 2-phenoxyethyl methacrylate) systems were determined by a static view cell apparatus at five temperatures (313.2, 333.2, 353.2, 373.2, and 393.2) K as well as pressures up to 31.43 MPa. Two {carbon dioxide + (meth)acrylate} systems had continuous critical mixture curves with maxima in pressure located between the critical temperatures of carbon dioxide and 2-phenoxyethyl (meth)acrylate. The solubility of 2-phenoxyethyl (meth)acrylate in the {carbon dioxide + 2-phenoxyethyl (meth)acrylate} systems increases as the temperature increases at a fixed pressure. The (carbon dioxide + 2-phenoxyethyl acrylate) and (carbon dioxide + 2-phenoxyethyl methacrylate) systems exhibit type-I phase behaviour. The experimental results for the (carbon dioxide + 2-phenoxyethyl acrylate) and (carbon dioxide + 2-phenoxyethyl methacrylate) systems correlate with the Peng-Robinson equation of state using a van der Waals one-fluid mixing rule including two adjustable parameters. The critical properties of 2-phenoxyethyl acrylate and 2-phenoxyethyl methacrylate were predicted with the Joback and Lee-Kesler method.