WorldWideScience

Sample records for carbonate approaching waterflood

  1. Smart Waterflooding in Carbonate Reservoirs

    DEFF Research Database (Denmark)

    Zahid, Adeel

    in porous media. The main conclusion of most previous studies was that it is the rock wettability alteration towards more water wetting condition that helps improving the oil recovery. In the first step of this project, we focused on verifying this conclusion. Coreflooding experiments were carried out using...... Stevens Klint outcrop chalk core plugs with brines without sulfate, as well as brines containing sulfate in different concentrations. The effects of temperature, injection rate, crude oil composition and different sulfate concentrations on the total oil recovery and the recovery rate were investigated...... that a heavy oil (that with a large fraction of heavy components) exhibited viscosity reduction in contact with brine, while a light crude oil exhibited emulsion formation. Most of reported high salinity waterflooding studies were carried out with outcrop chalk core plugs, and by performing spontaneous...

  2. Design and Implementation of a CO2 Flood Utilizing Advanced Reservoir Characterization and Horizontal Injection Wells In a Shallow Shelf Carbonate Approaching Waterflood Depletion, Class II

    Energy Technology Data Exchange (ETDEWEB)

    Wier, Don R. Chimanhusky, John S.; Czirr, Kirk L.; Hallenbeck, Larry; Gerard, Matthew G.; Dollens, Kim B.; Owen, Rex; Gaddis, Maurice; Moshell, M.K.

    2002-11-18

    The purpose of this project was to economically design an optimum carbon dioxide (CO2) flood for a mature waterflood nearing its economic abandonment. The original project utilized advanced reservoir characterization and CO2 horizontal injection wells as the primary methods to redevelop the South Cowden Unit (SCU). The development plans; project implementation and reservoir management techniques were to be transferred to the public domain to assist in preventing premature abandonment of similar fields.

  3. A New Comprehensive Approach for Predicting Injectivity Decline during Waterflooding

    DEFF Research Database (Denmark)

    Yuan, Hao; Nielsen, Sidsel Marie; Shapiro, Alexander;

    Injectivity decline during sea waterflooding or produced water re-injection is widely observed in North Sea, Gulf of Mexico and Campos Basin fields. The formation damage occurs mainly due to the deposition of suspended solids around injectors and the build-up the external filter cakes in the well...... bores. The ability to predict injectivity decline accurately is of great importance for project designs and water management. A comprehensive model that incorporates a variety of factors influencing the process is desirable for the prediction. In this paper, a new comprehensive approach for predicting...

  4. Design and implementation of a CO{sub 2} flood utilizing advanced reservoir characterization and horizontal injection wells in a shallow shelf carbonate approaching waterflood depletion. Quarterly report, April 1, 1995--June 30, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Wier, D.R.

    1995-09-01

    The first objective is to utilize reservoir characterization and advanced technologies to optimize the design of a CO{sub 2} project for the South Cowden Unit (SCU) located in Ector County, Texas. The SCU is a mature, relatively small, shallow shelf carbonate unit nearing waterflood depletion. The second objective is to demonstrate the performance and economic viability of the project in the field. The work reported here is on the reservoir characterization and project design objective. This objective is scheduled to be completed in early 1996 at which time work on the field demonstration phase is scheduled to begin.

  5. Integrated Approach Towards the Application of Horizontal Wells to Improve Waterflooding Performance

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, Mohan; Liner, Chris; Kerr, Dennis

    1999-10-15

    This final report describes the progress during the six year of the project on ''Integrated Approach Towards the Application of Horizontal Wells to Improve Waterflooding Performance.'' This report is funded under the Department of Energy's (DOE's) Class I program which is targeted towards improving the reservoir performance of mature oil fields located in fluvially-dominated deltaic deposits. The project involves using an integrated approach to characterize the reservoir followed by drilling of horizontal injection wells to improve production performance. The project was divided into two budget periods. In the first budget period, many modern technologies were used to develop a detailed reservoir management plan; whereas, in the second budget period, conventional data was used to develop a reservoir management plan. The idea was to determine the cost effectiveness of various technologies in improving the performance of mature oil fields.

  6. Design and implementation of a CO{sub 2} flood utilizing advanced reservoir characterization and horizontal injection wells in a shallow shelf carbonate approaching waterflood depletion. Annual report, June 3, 1994--October 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Hallenbeck, L.D.; Harpole, K.J.; Gerard, M.G.

    1996-05-01

    The work reported here covers Budget Phase I of the project. The principal tasks in Budget Phase I are the Reservoir Analysis and Characterization Task and the Advanced Technology Definition Task. Completion of these tasks have enabled an optimum carbon dioxide (CO{sub 2}) flood project to be designed and evaluated from an economic and risk analysis standpoint. Field implementation of the project has been recommended to the working interest owner of the South Cowden Unit (SCU) and approval has been obtained. The current project has focused on reducing initial investment cost by utilizing horizontal injection wells and concentrating the project in the best productivity area of the field. An innovative CO{sub 2} purchase agreement (no take or pay requirements, CO{sub 2} purchase price tied to West Texas Intermediate crude oil price) and gas recycle agreements (expensing cost as opposed to large capital investments for compression) were negotiated to further improve project economics. A detailed reservoir characterization study was completed by an integrated team of geoscientists and engineers. The study consisted of detailed core description, integration of log response to core descriptions, mapping of the major flow units, evaluation of porosity and permeability relationships, geostatistical analysis of permeability trends, and direct integration of reservoir performance with the geological interpretation. The study methodology fostered iterative bidirectional feedback between the reservoir characterization team and the reservoir engineering/simulation team to allow simultaneous refinement and convergence of the geological interpretation with the reservoir model. The fundamental conclusion from the study is that South Cowden exhibits favorable enhanced oil recovery characteristics, particularly reservoir quality and continuity.

  7. Geoscience/engineering characterization of the interwell environment in carbonate reservoirs based on outcrop analogs, Permian Basin, West Texas and New Mexico--waterflood performance analysis for the South Cowden Grayburg Reservoir, Ector County, Texas. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jennings, J.W. Jr.

    1997-05-01

    A reservoir engineering study was conducted of waterflood performance in the South Cowden field, an Upper Permian Grayburg reservoir on the Central Basin Platform in West Texas. The study was undertaken to understand the historically poor waterflood performance, evaluate three techniques for incorporating petrophysical measurements and geological interpretation into heterogeneous reservoir models, and identify issues in heterogeneity modeling and fluid-flow scaleup that require further research. The approach included analysis of relative permeability data, analysis of injection and production data, heterogeneity modeling, and waterflood simulation. The poor South Cowden waterflood recovery is due, in part, to completion of wells in only the top half of the formation. Recompletion of wells through the entire formation is estimated to improve recovery in ten years by 6 percent of the original oil in place in some areas of the field. A direct three-dimensional stochastic approach to heterogeneity modeling produced the best fit to waterflood performance and injectivity, but a more conventional model based on smooth mapping of layer-averaged properties was almost as good. The results reaffirm the importance of large-scale heterogeneities in waterflood modeling but demonstrate only a slight advantage for stochastic modeling at this scale. All the flow simulations required a reduction to the measured whole-core k{sub v}/k{sub h} to explain waterflood behavior, suggesting the presence of barriers to vertical flow not explicitly accounted for in any of the heterogeneity models. They also required modifications to the measured steady-state relative permeabilities, suggesting the importance of small-scale heterogeneities and scaleup. Vertical flow barriers, small-scale heterogeneity modeling, and relative permeability scaleup require additional research for waterflood performance prediction in reservoirs like South Cowden.

  8. Effect of stratification on segregation in carbon dioxide miscible flooding in a water-flooded oil reservoir

    International Nuclear Information System (INIS)

    Oil reservoirs are subjected to tertiary recovery by deploying any enhanced oil recovery (EOR) technique for the recovery of left over oil. Amongst many EOR methods one of the widely applied worldwide is CO/sub 2/ flooding through miscible, near miscible or immiscible displacement processes. CO/sub 2/ flooding process responds to a number of reservoir and fluid characteristics. These characteristics have strong effect on overall efficiency of the displacement process. Better understanding of the effect of different characteristics on displacement process is important to plan an efficient displacement process. In this work, the effect of stratification resulting in gravity segregation of the injected fluid is studied in an oil reservoir which is water-flooded during secondary phase of recovery. Sensitivity analysis is performed through successive simulation on Eclipse 300 (compositional) reservoir simulator. Process involves the continuous CO/sub 2/ injection in an oil reservoir with more than 1/3rd of original oil in place left after water flooding. Reservoir model with four different permeability layers is studied. Four patterns by changing the arrangement of the permeabilities of the layers are analysed. The effect of different arrangement or stratification on segregation of CO/sub 2/ and ultimately on the incremental oil recovery, is investigated. It has been observed that out of four arrangements, upward fining pattern relatively overcame the issue of the segregation of CO/sub 2/ and consequently 33% more oil with half injection volume is recovered when compared with the downward fining pattern. (author)

  9. Integrated approach towards the application of horizontal wells to improve waterflooding performance. Annual progress report, January 1, 1996--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Kelkar, M.; Liner, C.; Kerr, D.

    1997-01-01

    This annual report describes the progress during the fourth year of the project on {open_quotes}Integrated Approach Towards the Application of Horizontal Wells to Improve Waterflooding Performance{close_quotes}. The project involves using an integrated approach to characterize the reservoir followed by proposing an appropriate reservoir management strategy to improve the field performance. In the first stage of the project, the type of data we integrated include cross borehole seismic surveys, geological interpretation based on the logs and the cores, and the engineering information. In contrast, during the second stage of the project, we intend to use only conventional data to construct the reservoir description. This report covers the results of the implementation from the first stage of the project. It also discusses the work accomplished so far for the second stage of the project. The production from the Self Unit (location of Stage 1) has sustained an increase of 30 bbls/day over a year with an additional increase anticipated with further implementation. We have collected available core, log and production data from Section 16 in the Berryhill Glenn Unit and have finished the geological description. Based on the geological description and the associated petrophysical properties, we have developed a new indexing procedure for identifying the areas with the most potential. We are also investigating an adjoining tract formerly operated by Chevron where successful miceller-polymer flood was conducted. This will help us in evaluating the reasons for the success of the flood. Armed with this information, we will conduct a detailed geostatistical and flow simulation study and recommend the best reservoir management plan to improve the recovery of the field.

  10. Identification of waterflooded zones and the impact of waterflooding on reservoir properties of the Funing Formation in the Subei Basin, China

    Institute of Scientific and Technical Information of China (English)

    Peng-hui ZHANG; Jin-liang ZHANG; Wei-wei REN; Jun XIE; Ming LI; Jing-zhe LI; Fang DING; Jin-kai WANG; Zi-rui DONG

    2013-01-01

    This paper describes the identification ofwaterflooded zones and the impact ofwaterflooding on reservoir properties of sandstones of the Funing Formation at the Gao 6 Fault-block of the Gaoji Oilfield,in the Subei Basin,east China.This work presents a new approach based on a back-propagation neural network using well log data to train the network,and then generating a cross-plot plate to identify waterflooded zones.A neural network was designed and trained,and the results show that the new method is better than traditional methods.For a comparative study,two representative wells at the Gao 6 Fault-block were chosen for analysis: one from a waterflooded zone,and the other from a zone without waterflooding.Results from this analysis were used to develop a better understanding of the impact of waterflooding on reservoir properties.A range of changes are shown to have taken place in the waterflooded zone,including changes in microscopic pore structure,fluids,and minerals.

  11. A study of surfactant-assisted waterflooding

    Energy Technology Data Exchange (ETDEWEB)

    Scamehorn, J F; Harwell, J H

    1990-09-01

    In surfactant-assisted waterflooding, a surfactant slug is injected into a reservoir, followed by a brine spacer, followed by second surfactant slug. The charge on the surfactant in the first slug has opposite sign to that in the second slug. When the two slugs mix in the reservoir, a precipitate or coacervate is formed which plugs the permeable region of the reservoir. Subsequently injected water or brine is forced through the low permeability region of the reservoir, increasing sweep efficiency of the waterflood, compared to a waterflood not using surfactants. In this part of the work, two major tasks are performed. First, core floods are performed with oil present to demonstrate the improvement in incremental oil production, as well as permeability modification. Second, a reservoir simulation model will be proposed to further delineate the optimum strategy for implementation of the surfactant-assisted waterflooding, as well as indicate the reservoir types for which it would be most effective. Surfactants utilized were sodium dodecyl sulfate and dodecyl pyridinium chloride. 44 refs., 17 figs., 3 tabs.

  12. Modeling of Dissolution Effects on Waterflooding

    DEFF Research Database (Denmark)

    Alexeev, Artem; Shapiro, Alexander; Thomsen, Kaj

    2015-01-01

    Physico-chemical interactions between the fluid and reservoir rock due to the presence of active components in the injected brine produce changes within the reservoir and can significantly impact the fluid flow. We have developed a 1D numerical model for waterflooding accounting for dissolution a...

  13. PREFERRED WATERFLOOD MANAGEMENT PRACTICES FOR THE SPRABERRY TREND AREA

    Energy Technology Data Exchange (ETDEWEB)

    C. M. Sizemore; David S. Schechter

    2003-08-13

    This report describes the work performed during the second year of the project, ''Preferred Waterflood Management Practices for the Spraberry Trend Area''. The objective of this project is to significantly increase field-wide production in the Spraberry Trend in a short time frame through the application of preferred practices for managing and optimizing water injection. Our goal is to dispel negative attitudes and lack of confidence in water injection and to document the methodology and results for public dissemination to motivate waterflood expansion in the Spraberry Trend. To achieve this objective, in this period we concentrated our effort on characterization of Germania Unit using an analog field ET ODaniel unit and old cased hole neutron. Petrophysical Characterization of the Germania Spraberry units requires a unique approach for a number of reasons--limited core data, lack of modern log data and absence of directed studies within the unit. The need for characterization of the Germania unit has emerged as a first step in the review, understanding and enhancement of the production practices applicable within the unit and the trend area in general. In the absence or lack of the afore mentioned resources, an approach that will rely heavily on previous petrophysical work carried out in the neighboring ET O'Daniel unit (6.2 miles away), and normalization of the old log data prior to conventional interpretation techniques will be used. A log-based rock model has been able to guide successfully the prediction of pay and non-pay intervals within the ET O'Daniel unit, and will be useful if found applicable within the Germania unit. A novel multiple regression technique utilizing non-parametric transformations to achieve better correlations in predicting a dependent variable (permeability) from multiple independent variables (rock type, shale volume and porosity) will also be investigated in this study. A log data base includes digitized

  14. Sensitivity analysis of dimensionless parameters for physical simulation of water-flooding reservoir

    Institute of Scientific and Technical Information of China (English)

    BAI Yuhu; LI Jiachun; ZHOU Jifu

    2005-01-01

    A numerical approach to optimize dimensionless parameters of water-flooding porous media flows is proposed based on the analysis of the sensitivity factor defined as the variation ration of a target function with respect to the variation of dimensionless parameters. A complete set of scaling criteria for water-flooding reservoir of five-spot well pattern case is derived from the 3-D governing equations, involving the gravitational force,the capillary force and the compressibility of water, oil and rock. By using this approach,we have estimated the influences of each dimensionless parameter on experimental results, and thus sorting out the dominant ones with larger sensitivity factors ranging from 10-4 to 100.

  15. Waterflooding optimization in uncertain geological scenarios

    DEFF Research Database (Denmark)

    Capolei, Andrea; Suwartadi, Eka; Foss, Bjarne;

    2013-01-01

    of the permeability field from the production data. For open-loop implementations, previous test case studies presented in the literature, show that a traditional robust optimization strategy (RO) gives a higher expected NPV with lower NPV standard deviation than a conventional reactive strategy. We present and study......In conventional waterflooding of an oil field, feedback based optimal control technologies may enable higher oil recovery than with a conventional reactive strategy in which producers are closed based on water breakthrough. To compensate for the inherent geological uncertainties in an oil field......, robust optimization has been suggested to improve and robustify optimal control strategies. In robust optimization of an oil reservoir, the water injection and production borehole pressures (bhp) are computed such that the predicted net present value (NPV) of an ensemble of permeability field...

  16. Carbon Dioxide Removal via Passive Thermal Approaches

    Science.gov (United States)

    Lawson, Michael; Hanford, Anthony; Conger, Bruce; Anderson, Molly

    2011-01-01

    A paper describes a regenerable approach to separate carbon dioxide from other cabin gases by means of cooling until the carbon dioxide forms carbon dioxide ice on the walls of the physical device. Currently, NASA space vehicles remove carbon dioxide by reaction with lithium hydroxide (LiOH) or by adsorption to an amine, a zeolite, or other sorbent. Use of lithium hydroxide, though reliable and well-understood, requires significant mass for all but the shortest missions in the form of lithium hydroxide pellets, because the reaction of carbon dioxide with lithium hydroxide is essentially irreversible. This approach is regenerable, uses less power than other historical approaches, and it is almost entirely passive, so it is more economical to operate and potentially maintenance- free for long-duration missions. In carbon dioxide removal mode, this approach passes a bone-dry stream of crew cabin atmospheric gas through a metal channel in thermal contact with a radiator. The radiator is pointed to reject thermal loads only to space. Within the channel, the working stream is cooled to the sublimation temperature of carbon dioxide at the prevailing cabin pressure, leading to formation of carbon dioxide ice on the channel walls. After a prescribed time or accumulation of carbon dioxide ice, for regeneration of the device, the channel is closed off from the crew cabin and the carbon dioxide ice is sublimed and either vented to the environment or accumulated for recovery of oxygen in a fully regenerative life support system.

  17. Post Waterflood CO2 Miscible Flood in Light Oil, Fluvial-Dominated Deltaic Reservoir (Pre-Work and Project Proposal), Class I

    Energy Technology Data Exchange (ETDEWEB)

    Bou-Mikael, Sami

    2002-02-05

    This project outlines a proposal to improve the recovery of light oil from waterflooded fluvial dominated deltaic (FDD) reservoir through a miscible carbon dioxide (CO2) flood. The site is the Port Neches Field in Orange County, Texas. The field is well explored and well exploited. The project area is 270 acres within the Port Neches Field.

  18. Advances on interdisciplinary approaches to urban carbon

    Science.gov (United States)

    Romero-Lankao, P.

    2015-12-01

    North American urban areas are emerging as climate policy and technology innovators, urbanization process laboratories, fonts of carbon relevant experiments, hubs for grass-roots mobilization, and centers for civil-society experiments to curb carbon emissions and avoid widespread and irreversible climate impacts. Since SOCCR diverse lines of inquiry on urbanization, urban areas and the carbon cycle have advanced our understanding of some of the societal processes through which energy and land uses affect carbon. This presentation provides an overview of these diverse perspectives. It suggests the need for approaches that complement and combine the plethora of existing insights into interdisciplinary explorations of how different urbanization processes, and socio-ecological and technological components of urban areas affect the spatial and temporal patterns of carbon emissions, differentially over time and within and across cities. It also calls for a more holistic approach to examining the carbon implications of urbanization and urban areas as places, based not only on demographics or income, but also on such other interconnected features of urban development pathways as urban form, economic function, economic growth policies and climate policies.

  19. INCREASING WATERFLOOD RESERVES IN THE WILMINGTON OIL FIELD THROUGH IMPROVED RESERVOIR CHARACTERIZATION AND RESERVOIR MANAGEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Scott Walker; Chris Phillips; Roy Koerner; Don Clarke; Dan Moos; Kwasi Tagbor

    2002-02-28

    This project increased recoverable waterflood reserves in slope and basin reservoirs through improved reservoir characterization and reservoir management. The particular application of this project is in portions of Fault Blocks IV and V of the Wilmington Oil Field, in Long Beach, California, but the approach is widely applicable in slope and basin reservoirs. Transferring technology so that it can be applied in other sections of the Wilmington Field and by operators in other slope and basin reservoirs is a primary component of the project. This project used advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three-dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturated sands was stimulated by recompleting existing production and injection wells in these sands using conventional means as well as a short radius redrill candidate. Although these reservoirs have been waterflooded over 40 years, researchers have found areas of remaining oil saturation. Areas such as the top sand in the Upper Terminal Zone Fault Block V, the western fault slivers of Upper Terminal Zone Fault Block V, the bottom sands of the Tar Zone Fault Block V, and the eastern edge of Fault Block IV in both the Upper Terminal and Lower Terminal Zones all show significant remaining oil saturation. Each area of interest was uncovered emphasizing a different type of reservoir characterization technique or practice. This was not the original strategy but was necessitated by the different levels of progress in each of the project activities.

  20. A microvisual study of steamdrive mechanisms in waterflooded oil reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Xinmin, Song; Yongbin, Wu; Xiuluan, Li; Hongzhuang, Wang; Youwei Jiang [RIPED of CNPC (China); Xin, Zhao [Daqing Oilfield of CNPC (China)

    2011-07-01

    In conventional heavy and light oil reservoirs, waterflooding is used as a development technology but the oil recovery rates are usually low. In order to address this issue, steam injection has been tested and has performed well in pilot tests and industrialized application. The aim of this study is to present a model for visualizing pore scale EOR mechanisms. A high temperature high pressure (HTHP) micromodel was developed, it is housed in a pressure vessel with water bath for it to withstand high pressure and temperature conditions; experiments were undertaken using this tool. Results showed that the oil's thermal expansion, viscosity reduction and steam dilatation and wettability alteration are some of the EOR mechanisms. This study demonstrated that the steamflooding after waterflooding in porous media is an effective method for enhancing oil recovery through an improvement of the displacement efficiency.

  1. Experimental Study of Low Salinity Waterflooding and its Effect on Wettability

    OpenAIRE

    Kalvig, Sigrid Ingebjørg Hidle

    2011-01-01

    Many low salinity waterflooding studies have been performed, both in the laboratory and on the reservoir scale, over the last decades. These studies have proven that, under the right conditions, it is possible to get an enhanced oil recovery by reducing the salinity of the injecting water.This report presents laboratory core sample experiments on low salinity waterflooding and its effect on wettability, along with a literature study of low salinity waterflooding and rock wettability.Two set o...

  2. REFERRED WATERFLOOD MANAGEMENT PRACTICES FOR THE SPRABERRY TREND AREA

    Energy Technology Data Exchange (ETDEWEB)

    C. M. Sizemore; David S. Schechter

    2004-02-13

    This report describes the work performed during the first semi-annual third year of the project, ''Preferred Waterflood Management Practices for the Spraberry Trend Area''. The objective of this project is to significantly increase field-wide production in the Spraberry Trend in a short time frame through the application of preferred practices for managing and optimizing water injection. Our goal is to dispel negative attitudes and lack of confidence in water injection and to document the methodology and results for public dissemination to motivate waterflood expansion in the Spraberry Trend. To achieve this objective, in this period we concentrated our effort on analyzing production and injection data to optimize the reservoir management strategies for Germania Spraberry Unit. This study address the reservoir characterization and monitoring of the waterflooding project and propose alternatives of development of the current and future conditions of the reservoir to improve field performance. This research should serve as a guide for future work in reservoir simulation and can be used to evaluate various scenarios for additional development as well as to optimize the operating practices in the field. The results indicate that under the current conditions, a total of 1.410 million barrels of oil can be produced in the next 20 years through the 64 active wells and suggest that the unit can be successfully flooded with the current injection rate of 1600 BWPD and the pattern consisting of 6 injection wells aligned about 36 degrees respect to the major fracture orientation. In addition, a progress report on GSU waterflood pilot is reported for this period.

  3. Carbon Dioxide Sequestration, Weathering Approaches to

    Science.gov (United States)

    Schuiling, R. D.

    The aim of enhanced weathering is to capture CO2 by the carbonation of silicates, or by dissolution of these silicates during which the greenhouse gas CO2 is converted to bicarbonate in solution. Research in this field is still focused on increasing the rate of reaction, but the required additional technologies add considerably to the cost of the process. In this entry, the focus is on the optimization of the weathering conditions, by selecting the most reactive abundantly available minerals, grinding them, and spreading the grains over land. Thereafter nature takes its course. Since its formulation in the late 1990s, more and more people realize that this simple and natural approach may well turn out to be one of the most promising and environmentally friendliest ways to counteract climate change and ocean acidification

  4. Enhanced oil recovery by improved waterflooding. Second annual report

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

    Energy Resources Co. Inc. is currently operating a pilot polymer improved waterflood of the Storms Pool, a sandstone reservoir in the Illinois basin. During the second year of the project, progress was made in the laboratory work, field preparation, and computer simulation. Tasks II, VII, and IX, polymer selection, workovers, and model building were completed during 1979. The polymer selected is a xanthan type polysaccharide polymer. Other laboratory work included preliminary testing of biocides and oxygen scavengers. Development of the pilot area continued with the completion of the well workovers and the design and initiation of construction of the injection facility. Preliminary simulation was begun.

  5. Approaches to Promote China's Low Carbon Agricultural Development%Approaches to Promote China's Low Carbon Agricultural Development

    Institute of Scientific and Technical Information of China (English)

    Chen Yao

    2012-01-01

    Low carbon agriculture is a new production mode of green agriculture development to face the challenge of the global climate change, and a kind of innovation on developing circular agriculture. Up to now, low carbon agricultural development approaches are lacking of deep and systematical researches. Therefore, the paper briefly analyzed the situation and the existing problems of China's low carbon agricultural development, and then put forward the approaches to promote the low carbon agricultural development.

  6. Increasing Waterflooding Reservoirs in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management, Class III

    Energy Technology Data Exchange (ETDEWEB)

    Koerner, Roy; Clarke, Don; Walker, Scott; Phillips, Chris; Nguyen, John; Moos, Dan; Tagbor, Kwasi

    2001-08-07

    This project was intended to increase recoverable waterflood reserves in slope and basin reservoirs through improved reservoir characterization and reservoir management. The particular application of this project is in portions of Fault Blocks IV and V of the Wilmington Oil Field, in Long Beach, California, but the approach is widely applicable in slope and basin reservoirs, transferring technology so that it can be applied in other sections of the Wilmington field and by operators in other slope and basin reservoirs is a primary component of the project.

  7. Investigations on the possibility of improved oil recovery from the emsland reservoirs and development of an improved method of waterflooding

    Energy Technology Data Exchange (ETDEWEB)

    Hoefling, B.

    1965-12-01

    Literature studies have shown that oil recovery from the fields of Ruhlermoor and Bramberge, Emsland, Germany, can be improved by flooding, hot-water flooding, carbonated waterflooding, or in-situ combustion, but it is not economical to do so. The reservoirs being water-wet and containing viscous oil, it was investigated in the laboratory whether flooding with an emulsion stablized by an oil-soluble non-ionic surfactant is applicable. The experiments were conducted on sand packs with reservoir oil at formation temperature. It was found that a sufficiently large emulsion bank displaces most of the oil and the connate water without excessive water production. Best results were obtained with the higher viscosity oil, and when the system was first subjected to ordinary waterflooding. Piston-like oil displacement was achieved even in horizontally stratified systems, which is interesting because the natural reservoir also has permeability stratification. The data obtained, however, are not sufficient for a complete economical evaluation. (48 refs.)

  8. PREFERRED WATERFLOOD MANAGEMENT PRACTICES FOR THE SPRABERRY TREND AREA

    Energy Technology Data Exchange (ETDEWEB)

    David S. Schechter

    2004-08-31

    The naturally fractured Spraberry Trend Area is one of the largest reservoirs in the domestic U.S. and is the largest reservoir in area extent in the world. Production from Spraberry sands is found over a 2,500 sq. mile area and Spraberry reservoirs can be found in an eight county area in west Texas. Over 150 operators produce 65,000 barrels of oil per day (bopd) from the Spraberry Trend Area from more than 9,000 production wells. Recovery is poor, on the order of 7-10% due to the profoundly complicated nature of the reservoir, yet billions of barrels of hydrocarbons remain. We estimate over 15% of remaining reserves in domestic Class III reservoirs are in Spraberry Trend Area reservoirs. This tremendous domestic asset is a prime example of an endangered hydrocarbon resource in need of immediate technological advancements before thousands of wells are permanently abandoned. This report describes the final work of the project, ''Preferred Waterflood Management Practices for the Spraberry Trend Area.'' The objective of this project is to significantly increase field-wide production in the Spraberry Trend in a short time frame through the application of preferred practices for managing and optimizing water injection. Our goal is to dispel negative attitudes and lack of confidence in water injection and to document the methodology and results for public dissemination to motivate waterflood expansion in the Spraberry Trend. This objective has been accomplished through research in three areas: (1) detail historical review and extensive reservoir characterization, (2) production data management, and (3) field demonstration. This provides results of the final year of the three-year project for each of the three areas.

  9. Tropical forest carbon assessment: integrating satellite and airborne mapping approaches

    Energy Technology Data Exchange (ETDEWEB)

    Asner, Gregory P, E-mail: gpa@stanford.ed [Department of Global Ecology, Carnegie Institution for Science, 260 Panama Street, Stanford, CA 94305 (United States)

    2009-09-15

    Large-scale carbon mapping is needed to support the UNFCCC program to reduce deforestation and forest degradation (REDD). Managers of forested land can potentially increase their carbon credits via detailed monitoring of forest cover, loss and gain (hectares), and periodic estimates of changes in forest carbon density (tons ha{sup -1}). Satellites provide an opportunity to monitor changes in forest carbon caused by deforestation and degradation, but only after initial carbon densities have been assessed. New airborne approaches, especially light detection and ranging (LiDAR), provide a means to estimate forest carbon density over large areas, which greatly assists in the development of practical baselines. Here I present an integrated satellite-airborne mapping approach that supports high-resolution carbon stock assessment and monitoring in tropical forest regions. The approach yields a spatially resolved, regional state-of-the-forest carbon baseline, followed by high-resolution monitoring of forest cover and disturbance to estimate carbon emissions. Rapid advances and decreasing costs in the satellite and airborne mapping sectors are already making high-resolution carbon stock and emissions assessments viable anywhere in the world.

  10. Weathering approaches to carbon dioxide sequestration

    NARCIS (Netherlands)

    Schuiling, R.D.

    2012-01-01

    The aim of enhanced weathering is to capture CO2 by the carbonation of silicates, or by dissolution of these silicates during which the greenhouse gas CO2 is converted to bicarbonate in solution. Research in this field is still focused on increasing the rate of reaction, but the required additional

  11. Sustaining the emerging carbon trading industry development: A business ecosystem approach of carbon traders

    International Nuclear Information System (INIS)

    This paper explores how carbon traders nurture the business ecosystem to sustain the emerging carbon trading industry development. We collected primary data from a multinational carbon trader and its ecosystem partners in China, through the construction of interviews and documentary. The research findings show the carbon trading industry has experienced four-stage evolution with different driving forces; the carbon trader attracted and organized ecosystem partners to facilitate the CDM project owners to create carbon credits and trade them; a systematic business ecosystems approach through the lens of Context, Cooperation and Configuration, initiated by carbon traders, has facilitated the industry development. Our findings also implicate to industrial practitioners and policymakers for sustaining the emerging industry development at both the current- and the post-Kyoto protocol periods. - Highlights: • The carbon trader is a catalyst to link CDM project owner and trading market in China • The evolution of carbon trading industry has four stages with various driving forces. • Nurturing business ecosystems facilitates the carbon trading industry development. • The ecosystem approach works via the lens of Context, Configuration and Cooperation. • The ecosystem approach implicates to carbon trading industry at the post-Kyoto era

  12. The carbon control, a pragmatic approach

    International Nuclear Information System (INIS)

    Limit the greenhouse gases emissions is difficult, but not impossible. The authors takes stock on the possible technologies and solutions to solve this problem. From what they call ''stabilization triangle'' (difference between the emissions curves of increase and of stabilization), they presents scenario and solutions to reduce the carbon: the energy efficiency, the clean transports, the renewable energies, the political incentives, the international cooperation. (A.L.B.)

  13. Peatland geoengineering: an alternative approach to terrestrial carbon sequestration.

    Science.gov (United States)

    Freeman, Christopher; Fenner, Nathalie; Shirsat, Anil H

    2012-09-13

    Terrestrial and oceanic ecosystems contribute almost equally to the sequestration of ca 50 per cent of anthropogenic CO(2) emissions, and already play a role in minimizing our impact on Earth's climate. On land, the majority of the sequestered carbon enters soil carbon stores. Almost one-third of that soil carbon can be found in peatlands, an area covering just 2-3% of the Earth's landmass. Peatlands are thus well established as powerful agents of carbon capture and storage; the preservation of archaeological artefacts, such as ancient bog bodies, further attest to their exceptional preservative properties. Peatlands have higher carbon storage densities per unit ecosystem area than either the oceans or dry terrestrial systems. However, despite attempts over a number of years at enhancing carbon capture in the oceans or in land-based afforestation schemes, no attempt has yet been made to optimize peatland carbon storage capacity or even to harness peatlands to store externally captured carbon. Recent studies suggest that peatland carbon sequestration is due to the inhibitory effects of phenolic compounds that create an 'enzymic latch' on decomposition. Here, we propose to harness that mechanism in a series of peatland geoengineering strategies whereby molecular, biogeochemical, agronomical and afforestation approaches increase carbon capture and long-term sequestration in peat-forming terrestrial ecosystems.

  14. Approaching theoretical strength in glassy carbon nanolattices

    Science.gov (United States)

    Bauer, J.; Schroer, A.; Schwaiger, R.; Kraft, O.

    2016-04-01

    The strength of lightweight mechanical metamaterials, which aim to exploit material-strengthening size effects by their microscale lattice structure, has been limited by the resolution of three-dimensional lithography technologies and their restriction to mainly polymer resins. Here, we demonstrate that pyrolysis of polymeric microlattices can overcome these limitations and create ultra-strong glassy carbon nanolattices with single struts shorter than 1 μm and diameters as small as 200 nm. They represent the smallest lattice structures yet produced--achieved by an 80% shrinkage of the polymer during pyrolysis--and exhibit material strengths of up to 3 GPa, corresponding approximately to the theoretical strength of glassy carbon. The strength-to-density ratios of the nanolattices are six times higher than those of reported microlattices. With a honeycomb topology, effective strengths of 1.2 GPa at 0.6 g cm-3 are achieved. Diamond is the only bulk material with a notably higher strength-to-density ratio.

  15. Reservoir behavior and production rate using bottom waterflooding

    Energy Technology Data Exchange (ETDEWEB)

    Segovia C., A.G.

    1975-08-01

    Calculation of predictable behavior and assignment of production rate per well is a recommended procedure, based on Buckley and Leverett's theory on frontal displacement using bottom waterflooding. The study of a natural reservoir mechanism of production by hydraulic drive or gas-layer drive was made because they are rate sensitive. Production rates are established after a feasibile economic analysis. The production effect on final oil recovery must be established from the reservoir itself, to get more hydrocarbons efficiently, avoiding gas or water problems, and premature advance of the aquiferous or the gas layer. The calculation determines fundamental reservoir parameters which can be used to predict expected problems to be avoided with no risk. Most productive formations are thin but extended, and their exploitation is not economical if the equilibrium between oil and water production is broken down. When the characteristics are favorable, engineering analysis and study are used to yield optimal reservoir control and exploitation using frontal displacement mechanisms. 10 references.

  16. CARBON NANOTUBES: AN APPROACH TO NOVEL DRUG DELIVERY SYSTEM

    Directory of Open Access Journals (Sweden)

    M. H. Alai et al.

    2012-01-01

    Full Text Available Carbon nanotubes are cylindrical carbon molecules have novel properties, making them potentially useful in many applications in nanotechnology, electronics, optics, and other fields of material science as well as potential uses in architectural fields. They have unique electronic, mechanical, optical and chemical properties that make them good candidates for a wide variety of applications, including drug transporters, new therapeutics, delivery systems and diagnostics. Their unique surface area, stiffness, strength and resilience have led to much excitement in the field of pharmacy. Nanotubes are categorized as single-walled nanotubes, multiple walled nanotubes. Various techniques have been developed to produce nanotubes in sizeable quantities, including arc discharge, laser ablation, chemical vapor deposition. They can pass through membranes, carrying therapeutic drugs, vaccines and nucleic acids deep into the cell to targets previously unreachable. Purification of the tubes can be divided into a couple of main techniques: oxidation, acid treatment, annealing, sonication, filtering and functionalization techniques. The main problem of insolubility in aqueous media has been solved by developing a synthetic protocol that allows highly water-soluble carbon NTs to be obtained. The modifications are done to improve efficiency of carbon nanotubes by formulating luminescent carbon nanotubes, ultrathin carbon nanoneedles, magnetically guided nanotubes. The application of carbon nanotube in tissue engineering, drug carrier release system, wound healing, in cancer treatment and as biosensor. Researchers have recently developed a new approach to Boron Neutron Capture Therapy in the treatment of cancer using substituted Carborane-Appended Water-Soluble single-wall carbon nanotubes.

  17. The Status and Prospects of Enhancing Oil Recovery Technology for Waterflooding Oilfields in China

    Institute of Scientific and Technical Information of China (English)

    Shen Pingping; Yuan Shiyi

    1994-01-01

    @@ The water injection method has been used in most of oilfields in China even at the beginning of development, meanwhile the laboratory research on enhancing oil recovery (EOR) for these oilfields simultareously started too. Oilfields developed in 1960's have mostly been at a high watercut stage since 1990.Tasks in face of petroleum reservoir engineers are on the one hand, further improving recovery of waterflooding by integrated adjustments such as infill well drilling, water/oil ratio controlling, injection profile adjusting, etc. On the other hand, EOR techniques for waterflooding oilfields must be studied and applied to improve mostly the potential of underground resources and to increase recoverable reserves.

  18. Approaches for Landscape-scale Forest Carbon Assessment

    Science.gov (United States)

    Birdsey, R.; Pan, Y.; Wayson, C.; Johnson, K. D.; Zhang, F.; Chen, J. M.; Pinto, N.; Cook, B. D.; Masek, J. G.

    2011-12-01

    Increasingly, public and private forest landowners need to estimate their carbon stocks and analyze the impacts of alternate management plans. Here we describe approaches designed to work at landscape scales: one involves estimating carbon stocks from existing Forest Inventory and Analysis (FIA) data; another involves downscaling results from a continental-scale biogeochemistry model known as InTEC; and the third uses LiDAR remote sensing to provide high-resolution biomass maps. Combining FIA data with a biogeochemistry model gives the most useful information for analyzing causes of historical trends, while the biomass maps support implementation of management decisions. These approaches are illustrated by pilot studies in the Eastern U.S. Analysis of FIA data for Northern Wisconsin revealed that private landowners held more than half of the forest carbon but that the rate of carbon sequestration had slowed dramatically over two decades. Causes of the decline were hypothesized to include increased harvesting, aging forests, and increasing disturbances. The InTEC model for the same region revealed trends over a much longer historical period as well as providing information about changes in soil C that are lacking in the FIA data analysis. The effects of long-term forest age dynamics and higher interannual climate variability became evident, and there is evidence of a significant contribution to net sequestration from increasing soil C stocks. Using this information base, we identified several ways to increase landscape-scale average forest carbon stocks: allow some forests to reach full maturity and highest carbon stocks; manage other forests to maximize carbon uptake and transfer of harvested carbon into wood products; and avoid conversion of existing forests to nonforest land uses. Strategic implementation of these kinds of management decisions can be facilitated with high-resolution biomass maps.

  19. Using laboratory flow experiments and reactive chemical transport modeling for designing waterflooding of the Agua Fria Reservoir, Poza Rica-Altamira Field, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Birkle, P.; Pruess, K.; Xu, T.; Figueroa, R.A. Hernandez; Lopez, M. Diaz; Lopez, E. Contreras

    2008-10-01

    Waterflooding for enhanced oil recovery requires that injected waters must be chemically compatible with connate reservoir waters, in order to avoid mineral dissolution-and-precipitation cycles that could seriously degrade formation permeability and injectivity. Formation plugging is a concern especially in reservoirs with a large content of carbonates, such as calcite and dolomite, as such minerals typically react rapidly with an aqueous phase, and have strongly temperature-dependent solubility. Clay swelling can also pose problems. During a preliminary waterflooding pilot project, the Poza Rica-Altamira oil field, bordering the Gulf coast in the eastern part of Mexico, experienced injectivity loss after five months of reinjection of formation waters into well AF-847 in 1999. Acidizing with HCl restored injectivity. We report on laboratory experiments and reactive chemistry modeling studies that were undertaken in preparation for long-term waterflooding at Agua Frma. Using analogous core plugs obtained from the same reservoir interval, laboratory coreflood experiments were conducted to examine sensitivity of mineral dissolution and precipitation effects to water composition. Native reservoir water, chemically altered waters, and distilled water were used, and temporal changes in core permeability, mineral abundances and aqueous concentrations of solutes were monitored. The experiments were simulated with the multi-phase, nonisothermal reactive transport code TOUGHREACT, and reasonable to good agreement was obtained for changes in solute concentrations. Clay swelling caused an additional impact on permeability behavior during coreflood experiments, whereas the modeled permeability depends exclusively on chemical processes. TOUGHREACT was then used for reservoir-scale simulation of injecting ambient-temperature water (30 C, 86 F) into a reservoir with initial temperature of 80 C (176 F). Untreated native reservoir water was found to cause serious porosity and

  20. Induced migration of fines during waterflooding in communicating layer-cake reservoirs

    DEFF Research Database (Denmark)

    Yuan, Hao; Shapiro, Alexander

    2011-01-01

    The effects of fines migration induced by injection of water with a different salinity than the reservoir brine are incorporated into the upscaling model for waterflooding in a layer cake reservoir with good communication between the layers. Mobilization and re-capturing of the reservoir fines ma...

  1. A Novel Approach To Mineral Carbonation: Enhancing Carbonation While Avoiding Mineral Pretreatment Process Cost

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. McKelvy; Andrew V. G. Chizmeshya; Kyle Squires; Ray W. Carpenter; Hamdallah Bearat

    2006-06-21

    Known fossil fuel reserves, especially coal, can support global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other CO{sub 2} sequestration candidate technologies that propose long-term storage, mineral sequestration provides permanent disposal by forming geologically stable mineral carbonates. Carbonation of the widely occurring mineral olivine (e.g., forsterite, Mg{sub 2}SiO{sub 4}) is a large-scale sequestration process candidate for regional implementation, which converts CO{sub 2} into the environmentally benign mineral magnesite (MgCO{sub 3}). The primary goal is cost-competitive process development. As the process is exothermic, it inherently offers low-cost potential. Enhancing carbonation reactivity is key to economic viability. Recent studies at the U.S. DOE Albany Research Center have established that aqueous-solution carbonation using supercritical CO{sub 2} is a promising process; even without olivine activation, 30-50% carbonation has been achieved in an hour. Mechanical activation (e.g., attrition) has accelerated the carbonation process to an industrial timescale (i.e., near completion in less than an hour), at reduced pressure and temperature. However, the activation cost is too high to be economical and lower cost pretreatment options are needed. Herein, we report our second year progress in exploring a novel approach that offers the potential to substantially enhance carbonation reactivity while bypassing pretreatment activation. As our second year progress is intimately related to our earlier work, the report is presented in that context to provide better overall understanding of the progress made. We have discovered that robust silica-rich passivating layers form on the olivine surface during carbonation. As carbonation proceeds, these passivating layers thicken, fracture and eventually exfoliate, exposing fresh olivine surfaces during rapidly

  2. Bridging analytical approaches for low-carbon transitions

    Science.gov (United States)

    Geels, Frank W.; Berkhout, Frans; van Vuuren, Detlef P.

    2016-06-01

    Low-carbon transitions are long-term multi-faceted processes. Although integrated assessment models have many strengths for analysing such transitions, their mathematical representation requires a simplification of the causes, dynamics and scope of such societal transformations. We suggest that integrated assessment model-based analysis should be complemented with insights from socio-technical transition analysis and practice-based action research. We discuss the underlying assumptions, strengths and weaknesses of these three analytical approaches. We argue that full integration of these approaches is not feasible, because of foundational differences in philosophies of science and ontological assumptions. Instead, we suggest that bridging, based on sequential and interactive articulation of different approaches, may generate a more comprehensive and useful chain of assessments to support policy formation and action. We also show how these approaches address knowledge needs of different policymakers (international, national and local), relate to different dimensions of policy processes and speak to different policy-relevant criteria such as cost-effectiveness, socio-political feasibility, social acceptance and legitimacy, and flexibility. A more differentiated set of analytical approaches thus enables a more differentiated approach to climate policy making.

  3. Simple Approach to Synthesize Amino-Functionalized Carbon Dots by Carbonization of Chitosan

    Science.gov (United States)

    Liu, Xin; Pang, Jinhui; Xu, Feng; Zhang, Xueming

    2016-08-01

    Carbon dots (CDs) as a new series of fluorescent nanomaterials have drawn great attention in recent years owning to their unique properties. In this paper, a simple carbonization approach to synthesize amino-functionalized CDs was developed by using chitosan as the carbon precursor. The as-prepared CDs possessed desirable amino function group on their surface and exhibited bright luminescence with absolute quantum yield (QY) of 4.34%, excitation-, pH-dependent and up-conversion fluorescence behaviors. Furthermore, we have investigated the cytotoxicity and biocompatibility of the as-prepared CDs, which demonstrated that the as-prepared CDs have the potential applications in biosensing, cellular imaging and drug delivery.

  4. Simple Approach to Synthesize Amino-Functionalized Carbon Dots by Carbonization of Chitosan.

    Science.gov (United States)

    Liu, Xin; Pang, Jinhui; Xu, Feng; Zhang, Xueming

    2016-01-01

    Carbon dots (CDs) as a new series of fluorescent nanomaterials have drawn great attention in recent years owning to their unique properties. In this paper, a simple carbonization approach to synthesize amino-functionalized CDs was developed by using chitosan as the carbon precursor. The as-prepared CDs possessed desirable amino function group on their surface and exhibited bright luminescence with absolute quantum yield (QY) of 4.34%, excitation-, pH-dependent and up-conversion fluorescence behaviors. Furthermore, we have investigated the cytotoxicity and biocompatibility of the as-prepared CDs, which demonstrated that the as-prepared CDs have the potential applications in biosensing, cellular imaging and drug delivery. PMID:27492748

  5. A human needs approach to reducing atmospheric carbon

    Energy Technology Data Exchange (ETDEWEB)

    Moriarty, Patrick [Department of Industrial Design, Monash University, P.O. Box 197, Caulfield East 3145, Vic. (Australia); Honnery, Damon [Department of Mechanical and Aerospace Engineering, Monash University, P.O. Box 31, 3800 Vic. (Australia)

    2010-02-15

    Recent research has shown that once CO{sub 2} has been emitted to the atmosphere, it will take centuries for natural removal. Clearly, the longer we delay deep reductions in CO{sub 2}, the greater the risk that total greenhouse gas emissions will exceed prudent limits for avoiding dangerous anthropogenic change. We evaluate the three possible technical approaches for climate change mitigation: emission reduction methods, post-emission draw down of CO{sub 2} from the atmosphere, and geoengineering. We find that the first two approaches are unlikely to deliver the timely reductions in CO{sub 2} needed, while geoengineering methods either deliver too little or are too risky. Given the deep uncertainties in both future climate prediction and energy availability, it seems safest to actively plan for a much lower energy future. We propose a general 'shrink and share' approach to reductions in both fossil-fuel use and carbon emissions, with basic human needs satisfaction replacing economic growth as the focus for economic activity. Only with deep cuts in energy and carbon can we avoid burdening future generations with the high energy costs of air capture. (author)

  6. Microbial diversity and abundance in the Xinjiang Luliang long-term water-flooding petroleum reservoir

    OpenAIRE

    Gao, Peike; Tian, Huimei; Li, Guoqiang; Sun, Hongwen; Ma, Ting

    2015-01-01

    Microbial populations associated with microbial enhanced oil recovery (MEOR) and their abundance in the Xinjiang Luliang water-flooding petroleum reservoir were investigated using 16S rRNA, nitrate reductases, dissimilatory sulfate reductase, and methyl coenzyme-M reductase-encoded genes to provide ecological information for the potential application of MEOR. 16S rRNA gene miseq sequencing revealed that this reservoir harbored large amounts of taxa, including 155 bacterial and 7 archeal gener...

  7. B-SPLINE-BASED SVM MODEL AND ITS APPLICATIONS TO OIL WATER-FLOODED STATUS IDENTIFICATION

    Institute of Scientific and Technical Information of China (English)

    Shang Fuhua; Zhao Tiejun; Yi Xiongying

    2007-01-01

    A method of B-spline transform for signal feature extraction is developed. With the B-spline,the log-signal space is mapped into the vector space. An efficient algorithm based on Support Vector Machine (SVM) to automatically identify the water-flooded status of oil-saturated stratum is described.The experiments show that this algorithm can improve the performances for the identification and the generalization in the case of a limited set of samples.

  8. Induced migration of fines during waterflooding in communicating layer-cake reservoirs

    OpenAIRE

    Yuan, Hao; Shapiro, Alexander

    2011-01-01

    The effects of fines migration induced by injection of water with a different salinity than the reservoir brine are incorporated into the upscaling model for waterflooding in a layer cake reservoir with good communication between the layers. Mobilization and re-capturing of the reservoir fines may give rise to reduction of the permeability in water swept zones, which subsequently leads to the diversion of water flow from the initially more permeable layers to the less permeable ones. As a res...

  9. Increasing Waterflood Reserves in the Wilmington Oil Field through Improved Reservoir Characterization and Reservoir Management

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, D.; Koerner, R.; Moos D.; Nguyen, J.; Phillips, C.; Tagbor, K.; Walker, S.

    1999-04-05

    This project used advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three-dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturated sands was stimulated by recompleting existing production and injection wells in these sands using conventional means as well as a short radius redrill candidate.

  10. Approaches to greenhouse gas accounting methods for biomass carbon

    International Nuclear Information System (INIS)

    This investigation examines different approaches for the GHG flux accounting of activities within a tight boundary of biomass C cycling, with scope limited to exclude all other aspects of the lifecycle. Alternative approaches are examined that a) account for all emissions including biogenic CO2 cycling – the biogenic method; b) account for the quantity of C that is moved to and maintained in the non-atmospheric pool – the stock method; and c) assume that the net balance of C taken up by biomass is neutral over the short-term and hence there is no requirement to include this C in the calculation – the simplified method. This investigation demonstrates the inaccuracies in both emissions forecasting and abatement calculations that result from the use of the simplified method, which is commonly accepted for use. It has been found that the stock method is the most accurate and appropriate approach for use in calculating GHG inventories, however short-comings of this approach emerge when applied to abatement projects, as it does not account for the increase in biogenic CO2 emissions that are generated when non-CO2 GHG emissions in the business-as-usual case are offset. Therefore the biogenic method or a modified version of the stock method should be used to accurately estimate GHG emissions abatement achieved by a project. This investigation uses both the derivation of methodology equations from first principles and worked examples to explore the fundamental differences in the alternative approaches. Examples are developed for three project scenarios including; landfill, combustion and slow-pyrolysis (biochar) of biomass. -- Highlights: • Different approaches can be taken to account for the GHG emissions from biomass. • Simplification of GHG accounting methods is useful, however, can lead to inaccuracies. • Approaches used currently are often inadequate for practises that store carbon. • Accounting methods for emissions forecasting can be inadequate for

  11. Numerical studies of imaging subsurface waterfloods using CSERT with time-lapse inversion

    Science.gov (United States)

    Zhang, Ying-Ying; Liu, De-Jun; Wang, Li-Yang; Ai, Qing-Hui; Qin, Min-Jun

    2015-12-01

    During the operation of the waterflooding technique, it is necessary to identify the waterflooding areas to enhance oil displacement efficiency. A casing-surface electrical resistivity tomography (CSERT) system using a well casing as a long electrode is able to detect a wide lateral scope, but its vertical resolution and ability to identify deep anomalies in the reservoir are limited, particularly for reservoirs with high-conductivity anomalies in the shallow subsurface, which disturb the response from the water floods at depth. In this study, we first simplified this kind of reservoir into a dual layered anomaly model. Then the log-inject-log method with time-lapse inversion was proposed and evaluated regarding its ability to improve the imaging of the deep waterflooding areas and the shallow anomaly. The results were compared with the commonly used static measurement with static inversion. In the static inversion results, the shallow anomaly was imaged well but the deep anomaly was unobservable. The results of the proposed log-inject-log method with time-lapse inversion showed that it is able to identify the shallow and deep anomalies better under various conditions, thus validating its ability to improve the vertical resolution of the CSERT system.

  12. The UK transport carbon model: An integrated life cycle approach to explore low carbon futures

    International Nuclear Information System (INIS)

    Current debate focuses on the need for the transport sector to contribute to more ambitious carbon emission reduction targets. In the UK, various macro-economic and energy system wide, top-down models are used to explore the potential for energy demand and carbon emissions reduction in the transport sector. These models can lack the bottom-up, sectoral detail needed to simulate the effects of integrated demand and supply-side policy strategies to reduce emissions. Bridging the gap between short-term forecasting and long-term scenario “models”, this paper introduces a newly developed strategic transport, energy, emissions and environmental impacts model, the UK Transport Carbon Model (UKTCM). The UKTCM covers the range of transport–energy–environment issues from socio-economic and policy influences on energy demand reduction through to life cycle carbon emissions and external costs. The model is demonstrated in this paper by presenting the results of three single policies and one policy package scenario. Limitations of the model are also discussed. Developed under the auspices of the UK Energy Research Centre (UKERC) the UKTCM can be used to develop transport policy scenarios that explore the full range of technological, fiscal, regulatory and behavioural change policy interventions to meet UK climate change and energy security goals. - Research highlights: ►New strategic transport, energy, emissions and environmental impacts model. ►Tool to develop and analyse full consequences of multiple scenarios of transport policy packages. ►Novel approach to modelling demand for new vehicles by market and technology. ►Model available for use by research community via http://www.ukerc.ac.uk/support/tiki-index.php?page=UK+Transport+Carbon+Model.

  13. Novel approaches to understanding carbon redistribution at multiple scales

    Science.gov (United States)

    Dungait, Jennifer; Beniston, Joshua; Lal, Rattan; Horrocks, Claire; Collins, Adrian; Mariappen, Sankar; Quine, Timothy

    2014-05-01

    Established biogeochemical techniques are used to trace organic inputs typically derived directly or indirectly from plants into soils, sediments and water using lipid biomarkers. Recently, advances in bulk and compound specific stable 13C isotope analyses have provided novel ways of exploring the source and residence times of organic matter in soils using the natural abundance stable 13C isotope signature of C3 and C4 plant end member values. However, the application of biogeochemical source tracing technologies at the molecular level at field to catchment scales has been slow to develop because of perceived problems with dilution of molecular-scale signals. This paper describes the results of recent experiments in natural and agricultural environments in the UK (Collins et al., 2013; Dungait et al., 2013) and United States (Beniston et al., submitted) that have successfully applied new tracing techniques using stable 13C isotope and complementary approaches to explore the transport of sediment-bound organic carbon at a range of scales from the small plot (m2) to field (ha) and small catchment (10's ha). References Beniston et al (submitted) The effects of crop residue removal on soil erosion and macronutrient dynamics on soils under no till for 42 years. Biogeosciences Collins et al (2013) Catchment source contributions to the sediment-bound organic matter degrading salmonid spawning gravels in a lowland river, southern England. Science of the Total Environment 456-457, 181-195. Dungait et al (2013) Microbial responses to the erosional redistribution of soil organic carbon in arable fields. Soil Biology and Biochemistry 60, 195-201. Puttock et al (2012) Stable carbon isotope analysis of fluvial sediment fluxes over two contrasting C4-C3 semi-arid vegetation transitions. Rapid Communications in Mass Spectrometry 26, 2386-2392.

  14. Economic modelling approaches to cost estimates for the control of carbon dioxide emissions

    NARCIS (Netherlands)

    Zhang, Z.X.; Folmer, H.

    1998-01-01

    This article gives an assessment of the relative strengths and weaknesses of a variety of economic modelling approaches commonly used for cost estimates for limiting carbon emissions, including the ad hoc approach, dynamic optimization approach, input-output approach, macroeconomic approach, computa

  15. Effect of prolonged waterflooding of oil deposits on developing biocenosis and layer microflora activity

    Energy Technology Data Exchange (ETDEWEB)

    Berdichevskaya, M.V.

    1982-01-01

    It is shown that prolonged waterflooding of the oil layer with fresh water forms conditions for the spread and subsequent development of biocenosis of hydrocarbonaceous acid, sulpha-forming and methane-forming bacteria. The activity of the layer microflora under near natural conditions are determined. The 24 hour growth of bacterial biomass depending on such ecological factors as salinity and acidic-forming conditions varies from 0.138 to 0.408 mkM C/1. The time it takes for the bacterial biomass to double is given. Under varying ecologic conditions, it is from 18 to 120 h.

  16. Microbial diversity in long-term water-flooded oil reservoirs with different in situ temperatures in China

    OpenAIRE

    Fan Zhang; Yue-Hui She; Lu-Jun Chai; Banat, Ibrahim M.; Xiao-Tao Zhang; Fu-Chang Shu; Zheng-Liang Wang; Long-Jiang Yu; Du-Jie Hou

    2012-01-01

    Water-flooded oil reservoirs have specific ecological environments due to continual water injection and oil production and water recycling. Using 16S rRNA gene clone library analysis, the microbial communities present in injected waters and produced waters from four typical water-flooded oil reservoirs with different in situ temperatures of 25°C, 40°C, 55°C and 70°C were examined. The results obtained showed that the higher the in situ temperatures of the oil reservoirs is, the less the effec...

  17. Carbonate reservoir characterization. An integrated approach. 2. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Lucia, F. Jerry [Bureau of Economic Geology, Austin, TX (United States)

    2007-07-01

    What would the oil barons of Texas really like to know? Well, in the pages of this book they might find some answers. This hugely experienced author working in Texas, America's main oil-rich state, has produced a work that goes after one of the holy grails of oil prospecting. One main target in petroleum recovery is the description of the three-dimensional distribution of petrophysical properties on the interwell scale in carbonate reservoirs. Doing so would improve performance predictions by means of fluid-flow computer simulations. Lucia's book focuses on the improvement of geological, petrophysical, and geostatistical methods, describes the basic petrophysical properties, important geology parameters, and rock fabrics from cores, and discusses their spatial distribution. A closing chapter deals with reservoir models as an input into flow simulators. Not only does this book provide a hugely practical approach that uses geostatistical as well as petrophysical methods, it can also be used as course material to integrate geology, geophysics and engineering. (orig.)

  18. The GLOBE Carbon Cycle Project: Using a systems approach to understand carbon and the Earth's climate system

    Science.gov (United States)

    Silverberg, S. K.; Ollinger, S. V.; Martin, M. E.; Gengarelly, L. M.; Schloss, A. L.; Bourgeault, J. L.; Randolph, G.; Albrechtova, J.

    2009-12-01

    National Science Content Standards identify systems as an important unifying concept across the K-12 curriculum. While this standard exists, there is a recognized gap in the ability of students to use a systems thinking approach in their learning. In a similar vein, both popular media as well as some educational curricula move quickly through climate topics to carbon footprint analyses without ever addressing the nature of carbon or the carbon cycle. If students do not gain a concrete understanding of carbon’s role in climate and energy they will not be able to successfully tackle global problems and develop innovative solutions. By participating in the GLOBE Carbon Cycle project, students learn to use a systems thinking approach, while at the same time, gaining a foundation in the carbon cycle and it's relation to climate and energy. Here we present the GLOBE Carbon Cycle project and materials, which incorporate a diverse set of activities geared toward upper middle and high school students with a variety of learning styles. A global carbon cycle adventure story and game let students see the carbon cycle as a complete system, while introducing them to systems thinking concepts including reservoirs, fluxes and equilibrium. Classroom photosynthesis experiments and field measurements of schoolyard vegetation brings the global view to the local level. And the use of computer models at varying levels of complexity (effects on photosynthesis, biomass and carbon storage in global biomes, global carbon cycle) not only reinforces systems concepts and carbon content, but also introduces students to an important scientific tool necessary for understanding climate change.

  19. Vertically-integrated Approaches for Carbon Sequestration Modeling

    Science.gov (United States)

    Bandilla, K.; Celia, M. A.; Guo, B.

    2015-12-01

    Carbon capture and sequestration (CCS) is being considered as an approach to mitigate anthropogenic CO2 emissions from large stationary sources such as coal fired power plants and natural gas processing plants. Computer modeling is an essential tool for site design and operational planning as it allows prediction of the pressure response as well as the migration of both CO2 and brine in the subsurface. Many processes, such as buoyancy, hysteresis, geomechanics and geochemistry, can have important impacts on the system. While all of the processes can be taken into account simultaneously, the resulting models are computationally very expensive and require large numbers of parameters which are often uncertain or unknown. In many cases of practical interest, the computational and data requirements can be reduced by choosing a smaller domain and/or by neglecting or simplifying certain processes. This leads to a series of models with different complexity, ranging from coupled multi-physics, multi-phase three-dimensional models to semi-analytical single-phase models. Under certain conditions the three-dimensional equations can be integrated in the vertical direction, leading to a suite of two-dimensional multi-phase models, termed vertically-integrated models. These models are either solved numerically or simplified further (e.g., assumption of vertical equilibrium) to allow analytical or semi-analytical solutions. This presentation focuses on how different vertically-integrated models have been applied to the simulation of CO2 and brine migration during CCS projects. Several example sites, such as the Illinois Basin and the Wabamun Lake region of the Alberta Basin, are discussed to show how vertically-integrated models can be used to gain understanding of CCS operations.

  20. Effect of Pore-Scale Heterogeneity and Capillary-Viscous Fingering on Commingled Waterflood Oil Recovery in Stratified Porous Media

    Directory of Open Access Journals (Sweden)

    Emad W. Al-Shalabi

    2016-01-01

    Full Text Available Oil recovery prediction and field pilot implements require basic understanding and estimation of displacement efficiency. Corefloods and glass micromodels are two of the commonly used experimental methods to achieve this. In this paper, waterflood recovery is investigated using layered etched glass micromodel and Berea sandstone core plugs with large permeability contrasts. This study focuses mainly on the effect of permeability (heterogeneity in stratified porous media with no cross-flow. Three experimental setups were designed to represent uniformly stratified oil reservoir with vertical discontinuity in permeability. Waterflood recovery to residual oil saturation (Sor is measured through glass micromodel (to aid visual observation, linear coreflood, and forced drainage-imbibition processes by ultracentrifuge. Six oil samples of low-to-medium viscosity and porous media of widely different permeability (darcy and millidarcy ranges were chosen for the study. The results showed that waterflood displacement efficiencies are consistent in both permeability ranges, namely, glass micromodel and Berea sandstone core plugs. Interestingly, the experimental results show that the low permeability zones resulted in higher ultimate oil recovery compared to high permeability zones. At Sor microheterogeneity and fingering are attributed for this phenomenon. In light of the findings, conformance control is discussed for better sweep efficiency. This paper may be of help to field operators to gain more insight into microheterogeneity and fingering phenomena and their impact on waterflood recovery estimation.

  1. The fate of carbon in floodplain sediments: A biogeochemical approach

    Science.gov (United States)

    Alderson, Danielle; Evans, Martin; Rothwell, James; Boult, Stephen; Rhodes, Edward

    2015-04-01

    Inland waters including fluvial systems and their associated sediments have been predominantly overlooked as part of global carbon budgets until recently. In the UK, peatlands are dynamically eroding, with the eventual result being 'off-site' greenhouse gas emissions, which must be incorporated into carbon budgets for management strategies. Evans et al. (2013) concluded fluvial systems are active cyclers of carbon, with 50-90% of particulate organic carbon (POC) exported from peatlands eventually emitted as CO2. Floodplains, although commonly regarded as zones of carbon storage, have been identified as potential hotspots of carbon cycling in the fluvial system with a key process being decomposition of POC. Decomposition is known to involve mass loss with selective transformation of labile compounds such as polysaccharides, and preferential preservation of more resistant compounds (refractory aromatics or aliphatics). Several decomposition proxies including FTIR band intensities, hydrogen indices and C/N ratios, correlated with molecular structure determinations using pyrolysis GC-MS, have been used successfully in peat cores (Biester et al., 2013), to disentangle changes due to decomposition and those that are related to vegetation variation. The aim of this research is to determine whether similar techniques can be applied to arguably more complex systems such as floodplains, to examine stratigraphic records of carbon cycling. Initial results from sediment cores taken within a floodplain environment downstream of the Bleaklow Plateau in the Peak District, UK will be presented. An initial OSL date of 640±90 years BP together with assessment of the valley morphology using high resolution LiDAR DEM's indicate potential interaction of post glacial landslide features with the onset of substantial peat erosion, conditioning the landscape to interrupt the transport of carbon down the fluvial network. The floodplain under investigation is a potential hotspot for carbon

  2. A Simple Approach to Estimate Soil Organic Carbon and Soil CO2 Emission

    Directory of Open Access Journals (Sweden)

    Farhat Abbas

    2013-01-01

    Full Text Available SOC (Soil Organic Carbon and soil CO 2 (Carbon Dioxide emission are among the indicator of carbon sequestration and hence global climate change. Researchers in developed countries benefit from advance technologies to estimate C (Carbon sequestration. However, access to the latest technologies has always been challenging in developing countries to conduct such estimates. This paper presents a simple and comprehensive approach for estimating SOC and soil CO 2 emission from arable- and forest soils. The approach includes various protocols that can be followed in laboratories of the research organizations or academic institutions equipped with basic research instruments and technology. The protocols involve soil sampling, sample analysis for selected properties, and the use of a worldwide tested Rothamsted carbon turnover model. With this approach, it is possible to quantify SOC and soil CO 2 emission over short- and long-term basis for global climate change assessment studies.

  3. Dual template approach for the synthesis of hierarchically mesocellular carbon foams

    Institute of Scientific and Technical Information of China (English)

    Ming Xian Liu; Li Hua Gan; Ci Tian; Jian Chun Zhu; Zi Jie Xu; Zhi Xian Hao; Long Wu Chen

    2009-01-01

    We demonstrated a simple and effective dual-templating approach for the synthesis of hierarchically mesocellular carbon foams by using nonionic surfactant of sorbitan monooleate and silica colloid particles as sacrificial templates, and resorcinol/ formaldehyde as carbon source. The representative carbon foam has dual mesopore sizes of 4 and 10 nm, and possesses the specific surface area of 580 m2/g and the total pore volume of 0.80 cm3/g.

  4. Carbon accumulation of tropical peatlands over millennia: a modeling approach.

    Science.gov (United States)

    Kurnianto, Sofyan; Warren, Matthew; Talbot, Julie; Kauffman, Boone; Murdiyarso, Daniel; Frolking, Steve

    2015-01-01

    Tropical peatlands cover an estimated 440,000 km2 (~10% of global peatland area) and are significant in the global carbon cycle by storing about 40-90 Gt C in peat. Over the past several decades, tropical peatlands have experienced high rates of deforestation and conversion, which is often associated with lowering the water table and peat burning, releasing large amounts of carbon stored in peat to the atmosphere. We present the first model of long-term carbon accumulation in tropical peatlands by modifying the Holocene Peat Model (HPM), which has been successfully applied to northern temperate peatlands. Tropical HPM (HPMTrop) is a one-dimensional, nonlinear, dynamic model with a monthly time step that simulates peat mass remaining in annual peat cohorts over millennia as a balance between monthly vegetation inputs (litter) and monthly decomposition. Key model parameters were based on published data on vegetation characteristics, including net primary production partitioned into leaves, wood, and roots; and initial litter decomposition rates. HPMTrop outputs are generally consistent with field observations from Indonesia. Simulated long-term carbon accumulation rates for 11,000-year-old inland, and 5000-year-old coastal peatlands were about 0.3 and 0.59 Mg C ha(-1) yr(-1), and the resulting peat carbon stocks at the end of the 11,000-year and 5000-year simulations were 3300 and 2900 Mg C ha(-1), respectively. The simulated carbon loss caused by coastal peat swamp forest conversion into oil palm plantation with periodic burning was 1400 Mg C ha(-1) over 100 years, which is equivalent to ~2900 years of C accumulation in a hectare of coastal peatlands. PMID:25044171

  5. An approach to a black carbon emission inventory for Mexico by two methods

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Núñez, Xochitl, E-mail: xcruz@unam.mx

    2014-05-01

    A black carbon (BC) emission inventory for Mexico is presented. Estimate was performed by using two approaches, based on fuel consumption and emission factors in a top-down scheme, and the second from PM25 emission data and its correlation with black carbon by source category, assuming that black carbon = elemental carbon. Results show that black carbon emissions are in interval 53–473 Gg using the fuel consumption approach and between 62 and 89 using the sector method. Black carbon key sources come from biomass burning in the rural sector, with 47 percent share to the National total. Mobile sources emissions account to 16% to the total. An opportunity to reduce, in the short-term, carbon dioxide equivalent (CO2-eq) emissions by reducing black carbon emissions would be obtained in reducing emissions mainly from biomass burning in rural housing sector and diesel emissions in the transport sector with important co-benefits in direct radiative forcing, public health and air quality. - Highlights: • Black carbon emissions are estimated between 53 and 473 Gg/year on a fuel consumption method. • Black carbon emissions are estimated between 62 and 89 Gg/year on a sector method.

  6. A multiscale approach for estimating the chirality effects in carbon nanotube reinforced composites

    Science.gov (United States)

    Joshi, Unnati A.; Sharma, Satish C.; Harsha, S. P.

    2012-08-01

    In this paper, the multiscale representative volume element approach is proposed for modeling the elastic behavior of carbon nanotubes reinforced composites. The representative volume element incorporates the continuum approach, while carbon nanotube characterizes the atomistic approach. Space frame structure similar to three dimensional beams and point masses are employed to simulate the discrete geometrical constitution of the single walled carbon nanotube. The covalent bonds between carbon atoms found in the hexagonal lattices are assigned elastic properties using beam elements. The point masses applied on each node are coinciding with the carbon atoms work as mass of beam elements. The matrix phase is modeled as a continuum medium using solid elements. These two regions are interconnected by interfacial zone using beam elements. Analysis of nanocomposites having single walled carbon nanotube with different chiralities is performed, using an atomistic finite element model based on a molecular structural mechanics approach. Using the proposed multi scale model, the deformations obtained from the simulations are used to predict the elastic and shear moduli of the nanocomposites. A significant enhancement in the stiffness of the nanocomposites is observed. The effects of interfacial shear strength, stiffness, tensile strength, chirality, length of carbon nanotube, material of matrix, types of representative volume elements and types of loading conditions on the mechanical behavior of the nanocomposites are estimated. The finite element results are compared with the rule of mixtures using formulae. It is found that the results offered by proposed model, are in close proximity with those obtained by the rule of mixtures.

  7. A Novel Approach to Mineral Carbonation: Enhancing Carbonation While Avoiding Mineral Pretreatment Process Cost

    Energy Technology Data Exchange (ETDEWEB)

    Andrew V. G. Chizmeshya; Michael J. McKelvy; Kyle Squires; Ray W. Carpenter; Hamdallah Bearat

    2007-06-21

    Known fossil fuel reserves, especially coal, can support global energy demands for centuries to come, if the environmental problems associated with CO{sub 2} emissions can be overcome. Unlike other CO{sub 2} sequestration candidate technologies that propose long-term storage, mineral sequestration provides permanent disposal by forming geologically stable mineral carbonates. Carbonation of the widely occurring mineral olivine (e.g., forsterite, Mg{sub 2}SiO{sub 4}) is a large-scale sequestration process candidate for regional implementation, which converts CO{sub 2} into the environmentally benign mineral magnesite (MgCO{sub 3}). The primary goal is cost-competitive process development. As the process is exothermic, it inherently offers low-cost potential. Enhancing carbonation reactivity is key to economic viability. Recent studies at the U.S. DOE Albany Research Center have established that aqueous-solution carbonation using supercritical CO{sub 2} is a promising process; even without olivine activation, 30-50% carbonation has been achieved in an hour. Mechanical activation (e.g., attrition) has accelerated the carbonation process to an industrial timescale (i.e., near completion in less than an hour), at reduced pressure and temperature. However, the activation cost is too high to be economical and lower cost pretreatment options are needed. We have discovered that robust silica-rich passivating layers form on the olivine surface during carbonation. As carbonation proceeds, these passivating layers thicken, fracture and eventually exfoliate, exposing fresh olivine surfaces during rapidly-stirred/circulating carbonation. We are exploring the mechanisms that govern carbonation reactivity and the impact that (1) modeling/controlling the slurry fluid-flow conditions, (2) varying the aqueous ion species/size and concentration (e.g., Li+, Na+, K+, Rb+, Cl-, HCO{sub 3}{sup -}), and (3) incorporating select sonication offer to enhance exfoliation and carbonation. Thus

  8. Carbon stock in different ages and plantation systemof cocoa: allometric approach

    Directory of Open Access Journals (Sweden)

    Fitria Yuliasmara

    2009-08-01

    Full Text Available Indonesia has 1.5 million hectare of cocoa plantation in 2008. which hasstrategic position in carbon dioxide absorption to decrease global warming. Biomass approach method in plants carbon stock estimation specific for cocoa is still not available. The aim of this research is to determine carbon stock in 1—30 years ages of cocoa plants and to measure carbon stock in various cocoa planting systems using specific allometric formula of carbon stock estimation. Regression model on plant biomass estimation was estimated based on height, diameter, and their combination. Carbon stock estimation in different ages and plan tation system of cocoa was conducted by randomized completely block design with 3 replications. The result showed that model Y:áDâ as the best allometric formula, where Y is plant biomass, D is diameter at the breast hight, â is a constant with a value of 0.1208 and á was a constant of 1.98. Increasing of carbon stock in cocoa plantations was proportional to the ages of the plants according to the polinomial equation Y=0.0518X2+2.8976X–4.524. Agroforestry system increased carbon stock in cocoa plantation. Cocoa-Paraserianthes falcataria plantation system produce highest of carbon stock in 7 years. Key words : Carbon stock, allometric, cocoa, ages of plant, planting system.

  9. Post waterflood CO{sub 2} miscible flood in light oil, fluvial-dominated deltaic reservoir. FY 1993 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Davis, D.W.

    1995-03-01

    The project is a Class 1 DOE-sponsored field demonstration project of a CO{sub 2} miscible flood project at the Port Neches Field in Orange County, Texas. The project will determine the recovery efficiency of CO{sub 2} flooding a waterflooded and a partial waterdrive sandstone reservoir at a depth of 5,800. The project will also evaluate the use of a horizontal CO{sub 2} injection well placed at the original oil-water contact of the waterflooded reservoir. A PC-based reservoir screening model will be developed by Texaco`s research lab in Houston and Louisiana State University will assist in the development of a database of fluvial-dominated deltaic reservoirs where CO{sub 2} flooding may be applicable. This technology will be transferred throughout the oil industry through a series of technical papers and industry open forums.

  10. The shift of microbial population composition accompanying the injected water flowing in the water-flooding petroleum reservoirs

    OpenAIRE

    P. K. Gao; G. Q. Li; H. M. Tian; Y. S. Wang; Sun, H W; T. Ma

    2014-01-01

    In water-flooding petroleum reservoir, microbial populations in injected water are expected to migrate into oil-bearing strata and reach production wells. To demonstrate this, we firstly investigated microbial compositions in a homogeneous sandstone reservoir. The results indicated that the injected water harbored more microbial cells than produced water, and the shared populations and their abundance accounted for a minor fraction in injected water, while dominated i...

  11. Approaching theoretical strength in glassy carbon nanolattices.

    Science.gov (United States)

    Bauer, J; Schroer, A; Schwaiger, R; Kraft, O

    2016-04-01

    The strength of lightweight mechanical metamaterials, which aim to exploit material-strengthening size effects by their microscale lattice structure, has been limited by the resolution of three-dimensional lithography technologies and their restriction to mainly polymer resins. Here, we demonstrate that pyrolysis of polymeric microlattices can overcome these limitations and create ultra-strong glassy carbon nanolattices with single struts shorter than 1 μm and diameters as small as 200 nm. They represent the smallest lattice structures yet produced--achieved by an 80% shrinkage of the polymer during pyrolysis--and exhibit material strengths of up to 3 GPa, corresponding approximately to the theoretical strength of glassy carbon. The strength-to-density ratios of the nanolattices are six times higher than those of reported microlattices. With a honeycomb topology, effective strengths of 1.2 GPa at 0.6 g cm(-3) are achieved. Diamond is the only bulk material with a notably higher strength-to-density ratio. PMID:26828314

  12. Taxing Strategies for Carbon Emissions: A Bilevel Optimization Approach

    Directory of Open Access Journals (Sweden)

    Wei Wei

    2014-04-01

    Full Text Available This paper presents a quantitative and computational method to determine the optimal tax rate among generating units. To strike a balance between the reduction of carbon emission and the profit of energy sectors, the proposed bilevel optimization model can be regarded as a Stackelberg game between the government agency and the generation companies. The upper-level, which represents the government agency, aims to limit total carbon emissions within a certain level by setting optimal tax rates among generators according to their emission performances. The lower-level, which represents decision behaviors of the grid operator, tries to minimize the total production cost under the tax rates set by the government. The bilevel optimization model is finally reformulated into a mixed integer linear program (MILP which can be solved by off-the-shelf MILP solvers. Case studies on a 10-unit system as well as a provincial power grid in China demonstrate the validity of the proposed method and its capability in practical applications.

  13. Conversion of carbon dioxide to valuable petrochemicals:An approach to clean development mechanism

    Institute of Scientific and Technical Information of China (English)

    Farnaz Tahriri Zangeneh; Saeed Sahebdelfar; Maryam Takht Ravanchi

    2011-01-01

    The increase of atmospheric carbon dioxide and the global warming due to its greenhouse effect resulted in worldwide concerns. On the other hand, carbon dioxide might be considered as a valuable and renewable carbon source. One approach to reduce carbon dioxide emissions could be its capture and recycle via transformation into chemicals using the technologies in C1 chemistry. Despite its great interest, there are difficulties in CO2 separation on the one hand, and thermodynamic stability of carbon dioxide molecule rendering its chemical activity low on the other hand. Carbon dioxide has been already used in petrochemical industries for production of limited chemicals such as urea.The utilization of carbon dioxide does not necessarily involve development of new processes, and in certain processes such as methanol synthesis and methane steam reforming, addition of CO2 into the feed results in its utilization and increases carbon efficiency. In other cases,modifications in catalyst and/or processes, or even new catalysts and processes, are necessary. In either case, catalysis plays a crucial role in carbon dioxide conversion and effective catalysts are required for commercial realization of the related processes. Technologies for CO2 utilization are emerging after many years of research and development efforts.

  14. An approach to include soil carbon changes in life cycle assessments

    DEFF Research Database (Denmark)

    Petersen, Bjorn Molt; Knudsen, Marie Trydeman; Hermansen, John Erik;

    2013-01-01

    to estimate carbon sequestration to be included in LCA is suggested and applied to two examples where the inclusion of carbon sequestration is especially relevant: 1) Bioenergy: removal of straw from a Danish soil for energy purposes and 2) Organic versus conventional farming: comparative study of soybean......Globally, soil carbon sequestration is expected to hold a major potential to mitigate agricultural greenhouse gas emissions. However, the majority of life cycle assessments (LCA) of agricultural products have not included possible changes in soil carbon sequestration. In the present study, a method...... production in China. The suggested approach considers the time of the soil CO2 emissions for the LCA by including the Bern Carbon Cycle Model. Time perspectives of 20,100 and 200 years are used and a soil depth of 0-100 cm is considered. The application of the suggested method showed that the results were...

  15. Hydrogenation of carbon monoxide over nanostructured systems: A mechanochemical approach

    Science.gov (United States)

    Mulas, Gabriele; Campesi, Renato; Garroni, Sebastiano; Delogu, Francesco; Milanese, Chiara

    2011-07-01

    In this study we investigated the mechanochemical hydrogenation of carbon monoxide over nanostructured FeCo- and Mg 2Ni-based catalysts. To this aim powdered materials, prepared by mechanical alloying, were subjected to mechanical treatment under CO + H 2 atmosphere. A methodology to evaluate the activity of the solid catalysts on an absolute basis was developed. Conversion data were, indeed, expressed as turnover frequency, TOF, and related to the occurrence of ball to powder collision events through the mechanochemical turnover frequency parameter, MTOF. Differences in the catalytic activity and selectivity were observed for the two FeCo-based studied systems, the solid solution Fe 50Co 50 and its dispersion on TiO 2 support. As for the Mg 2Ni system, we explored the possibility to estimate the specific role of hydrogen pre-activation step. The catalytic properties of the mechanically alloyed Mg 2Ni system were compared with the conversion data shown by the same system pre-hydrogenated and subsequently milled under CO atmosphere.

  16. Powdered Activated Carbon: An Alternative Approach to Genomic DNA Purification.

    Science.gov (United States)

    Barbarić, Lucija; Bačić, Ivana; Grubić, Zorana

    2015-07-01

    Forensic evidence samples are routinely found as stains on various substrates, which may contain substances known to inhibit polymerase chain reaction (PCR). The goal of this study was to evaluate post-Chelex(®) 100 purification using powdered activated carbon (PAC). Mock crime scene DNA extracts were analyzed using quantitative PCR and short tandem repeat (STR) profiling to test the DNA recovery and inhibitor removal using PAC with those of the Amicon(®) Ultra 100K. For extracted bloodstains on soil and wood substrates, PAC and Amicon(®) Ultra 100K generated similar DNA yield and quality. Moreover, the two methods significantly decreased the concentration of humic substances and tannins compared to nonpurified extracts (p < 0.001). In instances where extracts contained indigo dye (bloodstains on denim), Amicon(®) Ultra 100K performed better than PAC due to improved amplifiability. Efficient adsorption of humic substances and tannins, which are common inhibitors, indicates PAC's potential application in the purification of high-template DNA extracts. PMID:25929735

  17. Carbon fluxes through food webs of the eastern equatorial Pacific: an inverse approach

    Science.gov (United States)

    Richardson, Tammi L.; Jackson, George A.; Ducklow, Hugh W.; Roman, Michael R.

    2004-09-01

    We used inverse and network analyses to examine food web interactions at 0°, 140°W during EqPac time-series cruises in March-April and October 1992. Our goal was to characterize carbon flows and trophic transfers while synthesizing the available information into a complete picture of ecosystem dynamics. The inverse approach allowed us to trace the pathway of fixed carbon through a representative food web and to characterize the role of various food web components in the recycling of carbon within, and export of carbon from, the euphotic zone. The key findings of these analyses were: (1) primary production of the larger phytoplankton size classes was most often dominated by the prymnesiophytes and pelagophytes and not by the diatoms, (2) picoplankton primary production was not always balanced by protozoan and microzooplankton grazing, despite conventional views of balanced microbial producer/grazer interactions in this system, (3) the picoplankton played an important direct + indirect role in the export of carbon from the euphotic zone through a pathway involving production of detritus from picoplankton carbon and subsequent grazing of this picoplankton-based detritus by the mesozooplankton, and (4) export of carbon through consumption of mesozooplankton by higher trophic levels was of the same magnitude as DOC export (9-25 mmol C m -2 d -1), yet this pathway is rarely considered in equatorial carbon balances.

  18. Study about Interpretation Models and Algorithm of Water-Flooded Formation Based on Resistivity

    Institute of Scientific and Technical Information of China (English)

    WANGYinghui; TANDehui; WANGQiongfang; CAIHongjie

    2005-01-01

    Many oil fields are developed by water injection in the world, it's difficult to interpret by welllogging information. EPT and C/O identify residual oil saturation or moveable oil, but they are only fit for oil-reservoir with porosity over 20%, and not for borehole. Additionally, Archie model is not completely fit for dynamic but the static oil-reservoir. Therefore, it's more difficult for WF (Water-flooded) oil-zone (dynamic oil-reservoir) with LPP (Low porosity and low permeability) to be interpreted. Resistivity logging series are the dominating tools to WF formation, so it becomes significantly important to research new interpretation models and algorithm based on resistivity well-logging for WF oil-zone with LPP. A set of new interpretation models for WFZ (Water flooded zone) are established according to the “U” type curve from experimentation, as well as according to mathematics analysis. The notable Archie model is only one case of these new models under special conditions. It is most important that these new models are all fit from exploration stage to development stage in oil field. At last, algorithm process and application result of these models are described.

  19. Prairie restoration and carbon sequestration: difficulties quantifying C sources and sinks using a biometric approach.

    Science.gov (United States)

    Cahill, Kimberly Nicholas; Kucharik, Christopher J; Foley, Jonathan A

    2009-12-01

    We investigated carbon cycling and ecosystem characteristics among two prairie restoration treatments established in 1987 and adjacent cropland, all part of the Conservation Reserve Program in southwestern Wisconsin, USA. We hypothesized that different plant functional groups (cool-season C3 vs. warm-season C4 grasses) between the two prairie restoration treatments would lead to differences in soil and vegetation characteristics and amount of sequestered carbon, compared to the crop system. We found significant (P soil CO2 respiration and above- and belowground productivity, but no significant differences in long-term (approximately 16-year) carbon sequestration. We used a biometric approach aggregating short-term observations of above- and belowground productivity and CO2 respiration to estimate total net primary production (NPP) and net ecosystem production (NEP) using varied methods suggested in the literature. Net ecosystem production is important because it represents the ecosystem carbon sequestration, which is of interest to land managers and policymakers seeking or regulating credits for ecosystem carbon storage. Such a biometric approach would be attractive because it might offer the ability to rapidly assess the carbon source/sink status of an ecosystem. We concluded that large uncertainties in (1) estimating aboveground NPP, (2) determining belowground NPP, and (3) partitioning soil respiration into microbial and plant components strongly affect the magnitude, and even the sign, of NEP estimates made from aggregating its components. A comparison of these estimates across treatments could not distinguish differences in NEP, nor the absolute sign of the overall carbon balance. Longer-term quantification of carbon stocks in the soil, periodically linked to measurements of individual processes, may offer a more reliable measure of the carbon balance in grassland systems, suitable for assigning credits. PMID:20014587

  20. Modeling the dynamics of carbon emission performance in China: A parametric Malmquist index approach

    International Nuclear Information System (INIS)

    This paper contributes to the existing literature on the methodology of modeling the dynamic of carbon emission performance. Based on the analytical framework of Zhou et al. (Energy Economics, 32, 194–201, 2010), we develop a parametric Malmquist index approach that takes into account statistical noises. Moreover, the fixed-effect panel stochastic frontier model is employed to deal with regional heterogeneity. The proposed approach is applied to analyze the dynamics of carbon emission performance in 30 Chinese provinces during the period of 2000–2010. The main findings are as follows. First, the carbon emission performances of 30 provinces as a whole improved by 4.1% annually during the sample period, which was mainly driven by efficiency change component. Second, the east area shows the best performance with an average Malmquist CO2 emissions performance index (MCPI) of 1.108, followed by the central area (1.039). Unlike the east and central areas, the west area experienced deterioration in carbon emission performance. More effective environmental policies should be implemented to change the situation. Third, compared with the proposed approach, the nonparametric approach tends to underestimate China's MCPI and gives rise to volatile results. - Highlights: • This paper analyzes the dynamics of carbon emission performance in China. • A parametric Malmquist index approach is presented. • China's carbon emission performance annually improved by 4.1% during the period 2000–2010. • Efficiency change is the major contributor to the improvement of China's MCPI

  1. Low carbon and clean energy scenarios for India: Analysis of targets approach

    International Nuclear Information System (INIS)

    Low carbon energy technologies are of increasing importance to India for reducing emissions and diversifying its energy supply mix. Using GCAM, an integrated assessment model, this paper analyzes a targets approach for pushing solar, wind, and nuclear technologies in the Indian electricity generation sector from 2005 to 2095. Targets for these technologies have been constructed on the basis of Indian government documents, policy announcements, and expert opinions. Different targets have been set for the reference scenario and the carbon price scenario. In the reference scenario, wind and nuclear technologies exceed respective targets in the long run without any subsidy push, while solar energy requires subsidy push throughout the century in order to meet its high targets. In the short run, nuclear energy also requires significant subsidy, including a much higher initial subsidy relative to solar power, which is a result of its higher targets. Under a carbon price scenario, the carbon price drives the penetration of these technologies. Still, subsidy is required — especially in the short run when the carbon price is low. We also found that pushing solar, wind, and nuclear technologies leads to a decrease in share of CCS under the carbon price scenario and biomass under both the reference and carbon price scenarios. This is because low carbon technologies compete among themselves and substitute each other, thereby enhancing the need for subsidy or carbon price, highlighting that proposed targets are not set at efficient levels. In light of contemporary debate on external costs of nuclear energy, we also assess the sensitivity of the results to nuclear technology cost. We find that higher cost significantly decreases the share of nuclear power under both the reference and carbon price scenarios.

  2. Multiple model approach to evaluation of accelerated carbonation for steelmaking slag in a slurry reactor.

    Science.gov (United States)

    Pan, Shu-Yuan; Liu, Hsing-Lu; Chang, E-E; Kim, Hyunook; Chen, Yi-Hung; Chiang, Pen-Chi

    2016-07-01

    Basic oxygen furnace slag (BOFS) exhibits highly alkaline properties due to its high calcium content, which is beneficial to carbonation reaction. In this study, accelerated carbonation of BOFS was evaluated under different reaction times, temperatures, and liquid-to-solid (L/S) ratios in a slurry reactor. CO2 mass balance within the slurry reactor was carried out to validate the technical feasibility of fixing gaseous CO2 into solid precipitates. After that, a multiple model approach, i.e., theoretical kinetics and empirical surface model, for carbonation reaction was presented to determine the maximal carbonation conversion of BOFS in a slurry reactor. On one hand, the reaction kinetics of BOFS carbonation was evaluated by the shrinking core model (SCM). Calcite (CaCO3) was identified as a reaction product through the scanning electronic microscopy and X-ray diffraction analyses, which provided the rationale of applying the SCM in this study. The rate-limiting step of carbonation was found to be ash-diffusion controlled, and the effective diffusivity for carbonation of BOFS in a slurry reactor were determined accordingly. On the other hand, the carbonation conversion of BOFS was predicted by the response surface methodology (RSM) via a nonlinear mathematical programming. According to the experimental data, the highest carbonation conversion of BOFS achieved was 57% under an L/S ratio of 20 mL g(-1), a CO2 flow rate of 0.1 L min(-1), and a pressure of 101.3 kPa at 50 °C for 120 min. Furthermore, the applications and limitations of SCM and RSM were examined and exemplified by the carbonation of steelmaking slags. PMID:27038901

  3. An approach to computing marginal land use change carbon intensities for bioenergy in policy applications

    International Nuclear Information System (INIS)

    Accurately characterizing the emissions implications of bioenergy is increasingly important to the design of regional and global greenhouse gas mitigation policies. Market-based policies, in particular, often use information about carbon intensity to adjust relative deployment incentives for different energy sources. However, the carbon intensity of bioenergy is difficult to quantify because carbon emissions can occur when land use changes to expand production of bioenergy crops rather than simply when the fuel is consumed as for fossil fuels. Using a long-term, integrated assessment model, this paper develops an approach for computing the carbon intensity of bioenergy production that isolates the marginal impact of increasing production of a specific bioenergy crop in a specific region, taking into account economic competition among land uses. We explore several factors that affect emissions intensity and explain these results in the context of previous studies that use different approaches. Among the factors explored, our results suggest that the carbon intensity of bioenergy production from land use change (LUC) differs by a factor of two depending on the region in which the bioenergy crop is grown in the United States. Assumptions about international land use policies (such as those related to forest protection) and crop yields also significantly impact carbon intensity. Finally, we develop and demonstrate a generalized method for considering the varying time profile of LUC emissions from bioenergy production, taking into account the time path of future carbon prices, the discount rate and the time horizon. When evaluated in the context of power sector applications, we found electricity from bioenergy crops to be less carbon-intensive than conventional coal-fired electricity generation and often less carbon-intensive than natural-gas fired generation. - Highlights: • Modeling methodology for assessing land use change emissions from bioenergy • Use GCAM

  4. The merit of sectoral approaches in transitioning towards a global carbon market

    OpenAIRE

    Fujiwara, Noriko; GEORGIEV Anton; Alessi, Monica

    2010-01-01

    The term 'sectoral approaches' means different things to different people. There are at least three main models of sectoral approaches: industry-led transnational initiatives linked to the deployment of sector-specific technologies; bottom-up developing country commitments, possibly combined with 'no-lose' targets; and a sectoral Clean Development Mechanism (CDM) or sectoral crediting with implications for carbon finance. There are a number of industry-led transnational initiatives, including...

  5. Technical efficiency of automobiles: A nonparametric approach incorporating carbon dioxide emissions

    OpenAIRE

    Hampf, Benjamin; Krüger, Jens

    2010-01-01

    We conduct an empirical analysis of the technical efficiency of cars sold in Germany in 2010. The analysis is performed using traditional data envelopment analysis (DEA) as well as directional distance functions (DDF). The approach of DDF allows incorporating the reduction of carbon dioxide emissions as an environmental goal in the efficiency analysis. A frontier separation approach is used to gain deeper insight for different car classes and regions of origin. Natural gas driven cars and spo...

  6. Holey carbon micro-arrays for transmission electron microscopy: A microcontact printing approach

    International Nuclear Information System (INIS)

    We have used a microcontact printing approach to produce high quality and inexpensive holey carbon micro-arrays. Fabrication involves: (1) micromolding a poly(dimethylsiloxane) (PDMS) elastomer stamp from a microfabricated master that contains the desired array pattern; (2) using the PDMS stamp for microcontact printing a thin sacrificial plastic film that contains an array of holes; (3) floating the plastic film onto TEM grids; (4) evaporating carbon onto the plastic film and (5) removing the sacrificial plastic film. The final holey carbon micro-arrays are ready for use as support films in TEM applications with the fidelity of the original microfabricated pattern. This approach is cost effective as both the master and the stamps have long-term reusability. Arbitrary array patterns can be made with microfabricated masters made through a single-step photolithographic process

  7. An approach for homogeneous carbon nanotube dispersion in Al matrix composites

    International Nuclear Information System (INIS)

    Highlights: • A novel approach was developed on the hot topic of carbon nanotube dispersion in composites. • Homogeneous carbon nanotube dispersion with a large aspect ratio and small damage was obtained. • Strength enhancement by carbon nanotube addition was examined by load transfer mechanism in Al matrix composites. • Al4C3 nano-rods were detected and helpful for load transfer in carbon nanotube/Al composites. - Abstract: Good dispersion of carbon nanotubes (CNTs) was the bottleneck to convert their attractive properties to CNT reinforced composites. In this study, a solution ball milling (SBM) approach was developed to homogeneously disperse CNTs in Al matrix composites (AMCs). The process integrated strategies of solution coating, mechanical ball milling and Al-flake producing into a simple organic unity. The dispersion quality, crystal-structure and strengthening effect of CNTs in AMCs processed by SBM were investigated through scanning electron microscopy, transmission electron microscopy, Raman analysis and tensile tests. Compared with previous methods, the SBM process was simple and effective to obtain a homogeneous CNT dispersion with a large aspect ratio and small CNT damages. Resultantly, the tensile strength of Al matrix was noticeably enhanced by CNT additions agreeing with the potential strengthening effect predicted by the load transfer mechanism

  8. Carbon exchange in Western Siberian watershed mires and implication for the greenhouse effect : A spatial temporal modeling approach

    OpenAIRE

    Borren, W.

    2007-01-01

    The vast watershed mires of Western Siberia formed a significant sink of carbon during the Holocene. Because of their large area these mires might play an important role in the carbon exchange between terrestrial ecosystems and the atmosphere. However, estimation of the Holocene and future carbon balance of whole Western Siberian mires is hampered by the lack of spatially resolved models. The main objective was to assess the carbon exchange fluxes of the mires using a 3-D dynamic approach. Th...

  9. Generic model for calculating carbon footprint of milk using four different LCA modelling approaches

    DEFF Research Database (Denmark)

    Dalgaard, Randi; Schmidt, Jannick Højrup; Flysjö, Anna

    2014-01-01

    The aim of the study is to develop a tool, which can be used for calculation of carbon footprint (using a life cycle assessment (LCA) approach) of milk both at a farm level and at a national level. The functional unit is ‘1 kg energy corrected milk (ECM) at farm gate’ and the applied methodology...... methodology for the dairy sector. The key elements of consequential LCA and the IDF guide are presented and explained by examples. The national carbon footprints (CF) for milk produced in Denmark and Sweden in 2005 are presented....

  10. A modelling approach to find stable and reliable soil organic carbon values for further regionalization.

    Science.gov (United States)

    Bönecke, Eric; Franko, Uwe

    2015-04-01

    Soil organic matter (SOM) and carbon (SOC) might be the most important components to describe soil fertility of agricultural used soils. It is sensitive to temporal and spatial changes due to varying weather conditions, uneven crops and soil management practices and still struggles with providing reliable delineation of spatial variability. Soil organic carbon, furthermore, is an essential initial parameter for dynamic modelling, understanding e.g. carbon and nitrogen processes. Alas it requires cost and time intensive field and laboratory work to attain and using this information. The objective of this study is to assess an approach that reduces efforts of laboratory and field analyses by using method to find stable initial soil organic carbon values for further soil process modelling and regionalization on field scale. The demand of strategies, technics and tools to improve reliable soil organic carbon high resolution maps and additionally reducing cost constraints is hence still facing an increasing attention of scientific research. Although, it is nowadays a widely used practice, combining effective sampling schemes with geophysical sensing techniques, to describe within-field variability of soil organic carbon, it is still challenging large uncertainties, even at field scale in both, science and agriculture. Therefore, an analytical and modelling approach might facilitate and improve this strategy on small and large field scale. This study will show a method, how to find reliable steady state values of soil organic carbon at particular points, using the approved soil process model CANDY (Franko et al. 1995). It is focusing on an iterative algorithm of adjusting the key driving components: soil physical properties, meteorological data and management information, for which we quantified the input and the losses of soil carbon (manure, crop residues, other organic inputs, decomposition, leaching). Furthermore, this approach can be combined with geophysical

  11. Causal nexus between energy consumption and carbon dioxide emission for Malaysia using maximum entropy bootstrap approach.

    Science.gov (United States)

    Gul, Sehrish; Zou, Xiang; Hassan, Che Hashim; Azam, Muhammad; Zaman, Khalid

    2015-12-01

    This study investigates the relationship between energy consumption and carbon dioxide emission in the causal framework, as the direction of causality remains has a significant policy implication for developed and developing countries. The study employed maximum entropy bootstrap (Meboot) approach to examine the causal nexus between energy consumption and carbon dioxide emission using bivariate as well as multivariate framework for Malaysia, over a period of 1975-2013. This is a unified approach without requiring the use of conventional techniques based on asymptotical theory such as testing for possible unit root and cointegration. In addition, it can be applied in the presence of non-stationary of any type including structural breaks without any type of data transformation to achieve stationary. Thus, it provides more reliable and robust inferences which are insensitive to time span as well as lag length used. The empirical results show that there is a unidirectional causality running from energy consumption to carbon emission both in the bivariate model and multivariate framework, while controlling for broad money supply and population density. The results indicate that Malaysia is an energy-dependent country and hence energy is stimulus to carbon emissions.

  12. Causal nexus between energy consumption and carbon dioxide emission for Malaysia using maximum entropy bootstrap approach.

    Science.gov (United States)

    Gul, Sehrish; Zou, Xiang; Hassan, Che Hashim; Azam, Muhammad; Zaman, Khalid

    2015-12-01

    This study investigates the relationship between energy consumption and carbon dioxide emission in the causal framework, as the direction of causality remains has a significant policy implication for developed and developing countries. The study employed maximum entropy bootstrap (Meboot) approach to examine the causal nexus between energy consumption and carbon dioxide emission using bivariate as well as multivariate framework for Malaysia, over a period of 1975-2013. This is a unified approach without requiring the use of conventional techniques based on asymptotical theory such as testing for possible unit root and cointegration. In addition, it can be applied in the presence of non-stationary of any type including structural breaks without any type of data transformation to achieve stationary. Thus, it provides more reliable and robust inferences which are insensitive to time span as well as lag length used. The empirical results show that there is a unidirectional causality running from energy consumption to carbon emission both in the bivariate model and multivariate framework, while controlling for broad money supply and population density. The results indicate that Malaysia is an energy-dependent country and hence energy is stimulus to carbon emissions. PMID:26282441

  13. Study and application on the evaluation method of porous formation for long-term waterflooding sand reservoir

    Institute of Scientific and Technical Information of China (English)

    Wang Changjiang; Jiang Hanqiao; Chen Minfeng; Geng Zhanli; Liu Pengfei

    2009-01-01

    Nine targets which stand both for the static characteristic of produced formations and the dynamic parameter of wells including the average permeability, variation coefficient of permeability, moving capability, remaining recoverable reserves, coefficient of flooding, daily oil production, increasing rate of water cut, cumulative liquid production per unit meter and efficiency index of oil production are selected as the evaluation indexes, a novel model to evaluate the porous formations in long-term waterflooding sand reservoir was established by using the support vector machine and clustering analysis. Data of 57 wefts from Shentuo 21 block Shengli oilfield was analyzed by using the model. Four kinds of forma-tion groups were gained. According to the analysis result, different adjustment solutions were put forward to develop the relevant formations. The Monthly oil production increased 7.6 % and the water cut decreased 8.9 % after the adjusted solutions. Good results indicate that the learning from this method gained will be valuable adding to other long-term wa-terflooding sand reservoirs in Shengli oilfield and other similar reservoirs worldwide.

  14. Plant diversity effects on ecosystem evapotranspiration and carbon uptake: a controlled environment (Ecotron) and modeling approach

    Science.gov (United States)

    Milcu, Alexandru; Roy, Jacques

    2016-04-01

    Effects of species and functional diversity of plants on ecosystem evapotranspiration and carbon fluxes have been rarely assessed simultaneously. Here we present the results from an experiment that combined a lysimeter setup in a controlled environment facility (Ecotron) with large ecosystem samples/ monoliths originating from a long-term biodiversity experiment ("The Jena Experiment") and a modelling approach. We aimed at (1) quantifying the impact of plant species richness (4 vs. 16 species) on day- and night-time ecosystem water vapor fluxes and carbon uptake, (2) partitioning ecosystem evapotranspiration into evaporation and plant transpiration using the Shuttleworth and Wallace (SW) energy partitioning model, and (3) identifying the most parsimonious predictors of water vapor vapor and CO2 fluxes using plant functional trait-based metrics such as functional diversity and community weighted means. The SW model indicated that at low plant species richness, a higher proportion of the available energy was diverted to evaporation (a non-productive flux), while at higher species richness the proportion of ecosystem transpiration (a production-related water flux) increased. This led to an increased carbon gain per amount of water vapor loss (i.e. increased water use efficiency). While the LAI controlled the carbon and water fluxes, we also found that the diversity of plant functional traits, and in particular of leaf nitrogen concentration are potential important predictors of ecosystem transpiration and carbon uptake and consequently significantly contributed to increase in water use efficiency in communities with higher plant diversity.

  15. New Approaches for Carbon Nanotubes-Based Biosensors and Their Application to Cell Culture Monitoring

    OpenAIRE

    Boero, Cristina; Olivo, Jacopo; De Micheli, Giovanni; Carrara, Sandro

    2012-01-01

    Amperometric biosensors are complex systems and they require a combination of technologies for their development. The aim of the present work is to propose a new approach in order to develop nanostructured biosensors for the real-time detection of multiple metabolites in cell culture flasks. The fabrication of five Au working electrodes onto silicon substrate is achieved with CMOS compatible microtechnology. Each working electrode presents an area of 0.25 mm2 , so structuration with carbon na...

  16. A Lamb waves based statistical approach to structural health monitoring of carbon fibre reinforced polymer composites.

    Science.gov (United States)

    Carboni, Michele; Gianneo, Andrea; Giglio, Marco

    2015-07-01

    This research investigates a Lamb-wave based structural health monitoring approach matching an out-of-phase actuation of a pair of piezoceramic transducers at low frequency. The target is a typical quasi-isotropic carbon fibre reinforced polymer aeronautical laminate subjected to artificial, via Teflon patches, and natural, via suitable low velocity drop weight impact tests, delaminations. The performance and main influencing factors of such an approach are studied through a Design of Experiment statistical method, considering both Pulse Echo and Pitch Catch configurations of PZT sensors. Results show that some factors and their interactions can effectively influence the detection of a delamination-like damage.

  17. A molecular mechanics approach for analyzing tensile nonlinear deformation behavior of single-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    Yu Wang; Daining Fang; Ai Kah Soh; Bin Liu

    2007-01-01

    In this paper, by capturing the atomic informa-tion and reflecting the behaviour governed by the nonlin-ear potential function, an analytical molecular mechanics approach is proposed. A constitutive relation for single-walled carbon nanotubes (SWCNT's) is established to describe the nonlinear stress-strain curve of SWCNT's and to predict both the elastic properties and breaking strain of SWCNT's during tensile deformation. An analysis based on the virtual internal bond (VIB) model proposed by P. Zhang et al. is also presented for comparison. The results indicate that the proposed molecular mechanics approach is indeed an acceptable analytical method for analyzing the mechanical behavior of SWCNT's.

  18. Bottom-Up Catalytic Approach towards Nitrogen-Enriched Mesoporous Carbons/Sulfur Composites for Superior Li-S Cathodes

    OpenAIRE

    Fugen Sun; Jitong Wang; Huichao Chen; Wenming Qiao; Licheng Ling; Donghui Long

    2013-01-01

    We demonstrate a sustainable and efficient approach to produce high performance sulfur/carbon composite cathodes via a bottom-up catalytic approach. The selective oxidation of H2S by a nitrogen-enriched mesoporous carbon catalyst can produce elemental sulfur as a by-product which in-situ deposit onto the carbon framework. Due to the metal-free catalytic characteristic and high catalytic selectivity, the resulting sulfur/carbon composites have almost no impurities that thus can be used as cath...

  19. Geological Carbon Sequestration: A New Approach for Near-Surface Assurance Monitoring

    Directory of Open Access Journals (Sweden)

    Lucian Wielopolski

    2011-03-01

    Full Text Available There are two distinct objectives in monitoring geological carbon sequestration (GCS: Deep monitoring of the reservoir’s integrity and plume movement and near-surface monitoring (NSM to ensure public health and the safety of the environment. However, the minimum detection limits of the current instrumentation for NSM is too high for detecting weak signals that are embedded in the background levels of the natural variations, and the data obtained represents point measurements in space and time. A new approach for NSM, based on gamma-ray spectroscopy induced by inelastic neutron scatterings (INS, offers novel and unique characteristics providing the following: (1 High sensitivity with a reducible error of measurement and detection limits, and, (2 temporal- and spatial-integration of carbon in soil that results from underground CO2 seepage. Preliminary field results validated this approach showing carbon suppression of 14% in the first year and 7% in the second year. In addition the temporal behavior of the error propagation is presented and it is shown that for a signal at the level of the minimum detection level the error asymptotically approaches 47%.

  20. Enhanced understanding of the terrestrial carbon cycle through multiple constraints in model-data-integration approaches

    Science.gov (United States)

    Carvalhais, N.; Forkel, M.; Oijen, M. V.; Keenan, T. F.; MacBean, N.; Rolinski, S.; Peylin, P. P.; Schuermann, G. J.; Zaehle, S.; Reichstein, M.

    2015-12-01

    The representation of exchanges of carbon, water and energy between the land surface and the atmosphere still reveals significant model limitations in explaining temporal and spatial variability. Despite agreement between models for contemporaneous periods, prognostic simulations reveal a strong between-model divergence regarding the role of the land surface in the global carbon cycle. The integration of multiple data-streams in inverse modelling approaches for parameterization and model evaluation, ultimately leads to model improvement. Here we explore multiple-constraint approaches ranging from in situ to regional and global spatial scales. Constraints include stocks and fluxes of water and carbon. We show that integrating multiple datasets contributes to a better representation of ecosystem dynamics in different models, from forest and dynamic vegetation models to land surface schemes. At site scale, model-data comparisons reveal substantial differences in the modelled temporal dynamics of carbon stocks and turnover times and their relationships with climate, especially at annual scales. Inter-annual variability remains a problem for all models, even after parameter optimization. At regional and global scales, the integration of multiple data-streams to constrain albedo, phenology and primary productivity patterns yields a significant improvement in regional simulations of vegetation dynamics, from seasons to longer-term trends. The role of environmental controls and vegetation dynamics in explaining recent trends in the amplitude of the seasonal cycle of atmospheric CO2 is evaluated using an improved dynamic vegetation model. We conclude by identifying major challenges in model-data-integration: to explore the information content in longer time series; avoid confounding effects of missing processes on parameter estimation; set up cost functions for multivariate-data integration; quantification of uncertainties arising from data bias, model structure, and

  1. A universal airborne LiDAR approach for tropical forest carbon mapping.

    Science.gov (United States)

    Asner, Gregory P; Mascaro, Joseph; Muller-Landau, Helene C; Vieilledent, Ghislain; Vaudry, Romuald; Rasamoelina, Maminiaina; Hall, Jefferson S; van Breugel, Michiel

    2012-04-01

    Airborne light detection and ranging (LiDAR) is fast turning the corner from demonstration technology to a key tool for assessing carbon stocks in tropical forests. With its ability to penetrate tropical forest canopies and detect three-dimensional forest structure, LiDAR may prove to be a major component of international strategies to measure and account for carbon emissions from and uptake by tropical forests. To date, however, basic ecological information such as height-diameter allometry and stand-level wood density have not been mechanistically incorporated into methods for mapping forest carbon at regional and global scales. A better incorporation of these structural patterns in forests may reduce the considerable time needed to calibrate airborne data with ground-based forest inventory plots, which presently necessitate exhaustive measurements of tree diameters and heights, as well as tree identifications for wood density estimation. Here, we develop a new approach that can facilitate rapid LiDAR calibration with minimal field data. Throughout four tropical regions (Panama, Peru, Madagascar, and Hawaii), we were able to predict aboveground carbon density estimated in field inventory plots using a single universal LiDAR model (r ( 2 ) = 0.80, RMSE = 27.6 Mg C ha(-1)). This model is comparable in predictive power to locally calibrated models, but relies on limited inputs of basal area and wood density information for a given region, rather than on traditional plot inventories. With this approach, we propose to radically decrease the time required to calibrate airborne LiDAR data and thus increase the output of high-resolution carbon maps, supporting tropical forest conservation and climate mitigation policy. PMID:22033763

  2. Data-based perfect-deficit approach to understanding climate extremes and forest carbon assimilation capacity

    International Nuclear Information System (INIS)

    Several lines of evidence suggest that the warming climate plays a vital role in driving certain types of extreme weather. The impact of warming and of extreme weather on forest carbon assimilation capacity is poorly known. Filling this knowledge gap is critical towards understanding the amount of carbon that forests can hold. Here, we used a perfect-deficit approach to identify forest canopy photosynthetic capacity (CPC) deficits and analyze how they correlate to climate extremes, based on observational data measured by the eddy covariance method at 27 forest sites over 146 site-years. We found that droughts severely affect the carbon assimilation capacities of evergreen broadleaf forest (EBF) and deciduous broadleaf forest. The carbon assimilation capacities of Mediterranean forests were highly sensitive to climate extremes, while marine forest climates tended to be insensitive to climate extremes. Our estimates suggest an average global reduction of forest CPC due to unfavorable climate extremes of 6.3 Pg C (∼5.2% of global gross primary production) per growing season over 2001–2010, with EBFs contributing 52% of the total reduction

  3. LIDAR-based urban metabolism approach to neighbourhood scale energy and carbon emissions modelling

    Energy Technology Data Exchange (ETDEWEB)

    Christen, A. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Geography; Coops, N. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Forest Sciences; Canada Research Chairs, Ottawa, ON (Canada); Kellet, R. [British Columbia Univ., Vancouver, BC (Canada). School of Architecture and Landscape Architecture

    2010-07-01

    A remote sensing technology was used to model neighbourhood scale energy and carbon emissions in a case study set in Vancouver, British Columbia (BC). The study was used to compile and aggregate atmospheric carbon flux, urban form, and energy and emissions data in a replicable neighbourhood-scale approach. The study illustrated methods of integrating diverse emission and uptake processes on a range of scales and resolutions, and benchmarked comparisons of modelled estimates with measured energy consumption data obtained over a 2-year period from a research tower located in the study area. The study evaluated carbon imports, carbon exports and sequestration, and relevant emissions processes. Fossil fuel emissions produced in the neighbourhood were also estimated. The study demonstrated that remote sensing technologies such as LIDAR and multispectral satellite imagery can be an effective means of generating and extracting urban form and land cover data at fine scales. Data from the study were used to develop several emissions reduction and energy conservation scenarios. 6 refs.

  4. Charge Modulation in Graphitic Carbon Nitride as a Switchable Approach to High-Capacity Hydrogen Storage.

    Science.gov (United States)

    Tan, Xin; Kou, Liangzhi; Tahini, Hassan A; Smith, Sean C

    2015-11-01

    Electrical charging of graphitic carbon nitride nanosheets (g-C4 N3 and g-C3 N4 ) is proposed as a strategy for high-capacity and electrocatalytically switchable hydrogen storage. Using first-principle calculations, we found that the adsorption energy of H2 molecules on graphitic carbon nitride nanosheets is dramatically enhanced by injecting extra electrons into the adsorbent. At full hydrogen coverage, the negatively charged graphitic carbon nitride achieves storage capacities up to 6-7 wt %. In contrast to other hydrogen storage approaches, the storage/release occurs spontaneously once extra electrons are introduced or removed, and these processes can be simply controlled by switching on/off the charging voltage. Therefore, this approach promises both facile reversibility and tunable kinetics without the need of specific catalysts. Importantly, g-C4 N3 has good electrical conductivity and high electron mobility, which can be a very good candidate for electron injection/release. These predictions may prove to be instrumental in searching for a new class of high-capacity hydrogen storage materials.

  5. Household energy consumption and carbon emissions for sustainable cities – A critical review of modelling approaches

    Directory of Open Access Journals (Sweden)

    Michael G. Oladokun

    2015-12-01

    Full Text Available The purpose of this paper is to conduct a review of how household energy consumption and carbon emissions (HECCE modelling paradigms have evolved over the years. This is achieved by adopting the literature review methodology for the study. The paper first reviewed the previous studies that are serving as the theoretical framework underpinning the HECCE models. Further to this, the paper identified an array of energy models that have evolved over the years together with their capability of analysing energy consumption and their associated carbon emission trends in housing sector of the economy. The results of the study showed that econometric (mainly top-down, building physics, and statistical (mainly bottom-up methods are the existing approaches that have found application in modelling HECCE issues. However, a number of limitations were noticed in these existing modelling techniques. These are (1 lack of transparency in the model algorithms, (2 inability to account for the complex, interdependencies, and dynamic nature of the issue of energy consumption and carbon emissions, (3 limited evidence to show for the occupants–dwelling interactions, and (4 lack of enough capacity to accommodate qualitative data input. And as such, the study concluded that there is the need to scout for more robust and sophisticated modelling approaches that take into consideration the kind of complexity involved in issues relating to HECCE.

  6. An inventory-based approach for estimating the managed China's forest biomass carbon stock

    Science.gov (United States)

    Huang, M.; Yu, G.; Yue, X.; Wang, J.

    2014-12-01

    China's forests cover a large area and have the characteristics of young age thus have the potential for a major role in mitigate the rate of global climate change. On the basis of forest inventory data and spatial distribution of forest stand age and forest type, we developed an approach for estimating yearly China's forest biomass carbon stocks change. Using this approach, we estimated the changes of forest carbon stock due to management practice and forest age structure change, respectively, and predicted China's future carbon potential based on national forest expansion plan. We also discussed sustainable harvesting intensity for the expanded forest of 2020. The spatial pattern of forest biomass carbon density in 2001 showed high in southwestern and northeastern areas, and low in the other regions, meanwhile the high C sinks appeared in the southwestern and northeastern young-aged forests and low in the southwestern and northeastern old-aged forests. The total forest biomass C stock of China increased from 6.06 Pg C in 2001 to 7.88 Pg C in 2013, giving a total increase of 1.82 Pg C, in which 0.45 Pg C is caused by forest expansion. The average C sink during 2002-2013 was 151.83 Tg C, in which 75.5% is the results of forest growth and 24.5% is caused by forest expansion. With the assumption of China's forest area will expand by 40 million hectares from 2006 to 2020, the forest C stock in 2020 is predicted as 9.04 Pg C. Harvesting intensity experiments conducted on the expanded forest of 2020 shown higher harvesting level will lead to decline in forest biomass in long term. The harvesting level of 2% is an optimal harvesting intensity for sustainable development of China's forest resources.

  7. Modeling the binding affinity of structurally diverse industrial chemicals to carbon using the artificial intelligence approaches.

    Science.gov (United States)

    Gupta, Shikha; Basant, Nikita; Rai, Premanjali; Singh, Kunwar P

    2015-11-01

    Binding affinity of chemical to carbon is an important characteristic as it finds vast industrial applications. Experimental determination of the adsorption capacity of diverse chemicals onto carbon is both time and resource intensive, and development of computational approaches has widely been advocated. In this study, artificial intelligence (AI)-based ten different qualitative and quantitative structure-property relationship (QSPR) models (MLPN, RBFN, PNN/GRNN, CCN, SVM, GEP, GMDH, SDT, DTF, DTB) were established for the prediction of the adsorption capacity of structurally diverse chemicals to activated carbon following the OECD guidelines. Structural diversity of the chemicals and nonlinear dependence in the data were evaluated using the Tanimoto similarity index and Brock-Dechert-Scheinkman statistics. The generalization and prediction abilities of the constructed models were established through rigorous internal and external validation procedures performed employing a wide series of statistical checks. In complete dataset, the qualitative models rendered classification accuracies between 97.04 and 99.93%, while the quantitative models yielded correlation (R(2)) values of 0.877-0.977 between the measured and the predicted endpoint values. The quantitative prediction accuracies for the higher molecular weight (MW) compounds (class 4) were relatively better than those for the low MW compounds. Both in the qualitative and quantitative models, the Polarizability was the most influential descriptor. Structural alerts responsible for the extreme adsorption behavior of the compounds were identified. Higher number of carbon and presence of higher halogens in a molecule rendered higher binding affinity. Proposed QSPR models performed well and outperformed the previous reports. A relatively better performance of the ensemble learning models (DTF, DTB) may be attributed to the strengths of the bagging and boosting algorithms which enhance the predictive accuracies. The

  8. Carbon balance assessment of a natural steppe of southern Siberia by multiple constraint approach

    Directory of Open Access Journals (Sweden)

    L. Belelli Marchesini

    2007-01-01

    Full Text Available Steppe ecosystems represent an interesting case in which the assessment of carbon balance may be performed through a cross validation of the eddy covariance measurements against ecological inventory estimates of carbon exchanges (Ehman, 2002; Curtis, 2002.

    Indeed, the widespread presence of ideal conditions for the applicability of the eddy covariance technique, as vast and homogeneous grass vegetation cover over flat terrains (Baldocchi, 2003, make steppes a suitable ground to ensure a constrain to flux estimates with independent methodological approaches.

    We report about the analysis of the carbon cycle of a true steppe ecosystem in southern Siberia during the growing season of 2004 in the framework of the TCOS-Siberia project activities performed by continuous monitoring of CO2 fluxes at ecosystem scale by the eddy covariance method, fortnightly samplings of phytomass, and ingrowth cores extractions for NPP assessment, and weekly measurements of heterotrophic component of soil CO2 effluxes obtained by an experiment of root exclusion.

    The carbon balance of the monitored natural steppe was, according to micrometeorological measurements, a sink of carbon of 151.7± 30.1 gC m−2, cumulated during the growing season from May to September. This result was in agreement with the independent estimate through ecological inventory which yielded a sink of 150.1 gC m−2 although this method was characterized by a large uncertainty (±130% considering the 95% confidence interval of the estimate. Uncertainties in belowground process estimates account for a large part of the error. Thus, in particular efforts to better quantify the dynamics of root biomass (growth and turnover have to be undertaken in order to reduce the uncertainties in the assessment of NPP. This assessment should be preferably based on the application of multiple methods, each one characterized by its own merits and

  9. A paired flux approach to study the carbon balance of a corn/soybean rotation

    Science.gov (United States)

    Baker, J.; Griffis, T.

    2003-04-01

    producing acceptable data. We used this approach to examine a common crop rotation in the Midwestern United States, alternation of corn and soybean. One field was farmed conventionally, while in the other we employed two practices expected to favor carbon gain: reduced tillage and the use of a spring cover crop prior to soybean. Carbon exchange rate and latent heat flux were measured by eddy covariance in both fields for an entire year, dating from harvest of corn to harvest of soybean. Data were screened to remove all time periods when either of the two fields did not meet acceptance criteria. Differential analysis of the remaining data showed that the alternative practices did indeed have a discernible impact. With respect to carbon balance, the effect of reduced tillage was subtle but positive, in the form of lower respiration losses during fall and early spring. The impact of the spring cover crop (oats) was much more significant. As for water balance, there was almost no difference in cumulative latent heat flux; higher offseason evaporation from the conventionally-tilled field was nearly offset by the higher ET from the spring cover crop, relative to the bare soil in the conventional treatment. Soybean yields were also nearly identical for the two fields. We conclude that these practices can improve carbon balance, with little or no impact on yield or annual water use.

  10. Theoretical eduction and numerical simulation researches on the relationship between resistivity and water saturation of waterflood oil zone

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In the process of water displacing oil,the relationship between resistivity and water saturation is the fundament of the quantitative research on the waterflooded grade and the remaining oil saturation with well logging data. A large number of core analysis data and production data are cumulated in the process of oil field exploitation,which offers the basis for the above research. This paper educed two methods from the Archie equation and material balance theory to calculate the quantitative relationships between Rz and Sw,and between Rt and Sw. The relationships set up by the two methods are similar to those set up by the real core measurements. The results can be used to analyze influencing factors and determine saturation quantitatively.

  11. An Artificial Intelligence Approach for Modeling and Prediction of Water Diffusion Inside a Carbon Nanotube

    Directory of Open Access Journals (Sweden)

    Ahadian Samad

    2009-01-01

    Full Text Available Abstract Modeling of water flow in carbon nanotubes is still a challenge for the classic models of fluid dynamics. In this investigation, an adaptive-network-based fuzzy inference system (ANFIS is presented to solve this problem. The proposed ANFIS approach can construct an input–output mapping based on both human knowledge in the form of fuzzy if-then rules and stipulated input–output data pairs. Good performance of the designed ANFIS ensures its capability as a promising tool for modeling and prediction of fluid flow at nanoscale where the continuum models of fluid dynamics tend to break down.

  12. An approach to a multi walled carbon nanotube based mass sensor

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Davis, Zachary James; Madsen, Dorte Nørgaard;

    2004-01-01

    We propose an approach to a nanoscale mass sensor based on a gold electrode structure, on which a multi-walled carbon nanotube (MWCNT) bridge can be placed and soldered. The structure is comprised of three electrodes with a width of 2 or 4 mum. Two outer electrodes with a length of 10 or 15 mum...... the bridging nanotube. The free standing MWCNTs were fabricated by chemical vapour deposition of Fe(H) phthalocyanine. A nanomanipulator with an x - y - z translation stage was used for placing the MWCNTs across the source-drain electrodes. The nanotubes were soldered onto the substrate by electron beam...

  13. Seeking optimal performance of multiwall carbon nanotubes in field emission: Tight-binding approach

    Science.gov (United States)

    Liang, Shi-Dong; Deng, Shao Zhi; Xu, Ning Sheng

    2006-10-01

    The field emission performance of different components of multiwall carbon nanotubes (MWCNs) is systematically studied by quantum tunneling theory with the tight-binding approach. We find that the current-voltage characteristic in field emission of MWCNs still approximately follows the Fowler-Nordheim theory. The key characteristics of all MWCNs are almost independent of the component and the layer number of MWCNs that have more three layers. The interlayer coupling of MWCNs can induce a semiconductor-metal phase transition, which leads to most MWCNs being actually metallic, and the chiral and quantum size effects disappear.

  14. A Theoretic Approach to SU(4) Kondo Effect in Carbon Nanotube Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    ZHU Rui

    2006-01-01

    We propose a mean Geld approach to the transport properties of carbon nanotube quantum dots. Quantum interaction between spin and orbital pseudo-spin degrees of freedom results in an SU(4) Kondo effect at low temperatures. By calculating the chemical potentials and the tunnelling strengths, and hence the spectral functions for different coupling constants and applied magnetic fields, we find that this exotic Kondo effect manifests as a four-peak splitting in the non-linear conductance when an axial magnetic field is applied.

  15. An Artificial Intelligence Approach for Modeling and Prediction of Water Diffusion Inside a Carbon Nanotube

    Science.gov (United States)

    2009-01-01

    Modeling of water flow in carbon nanotubes is still a challenge for the classic models of fluid dynamics. In this investigation, an adaptive-network-based fuzzy inference system (ANFIS) is presented to solve this problem. The proposed ANFIS approach can construct an input–output mapping based on both human knowledge in the form of fuzzy if-then rules and stipulated input–output data pairs. Good performance of the designed ANFIS ensures its capability as a promising tool for modeling and prediction of fluid flow at nanoscale where the continuum models of fluid dynamics tend to break down. PMID:20596382

  16. A simplified, data-constrained approach to estimate the permafrost carbon-climate feedback.

    Science.gov (United States)

    Koven, C D; Schuur, E A G; Schädel, C; Bohn, T J; Burke, E J; Chen, G; Chen, X; Ciais, P; Grosse, G; Harden, J W; Hayes, D J; Hugelius, G; Jafarov, E E; Krinner, G; Kuhry, P; Lawrence, D M; MacDougall, A H; Marchenko, S S; McGuire, A D; Natali, S M; Nicolsky, D J; Olefeldt, D; Peng, S; Romanovsky, V E; Schaefer, K M; Strauss, J; Treat, C C; Turetsky, M

    2015-11-13

    We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation-Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soil temperature. The trajectories are determined according to a three-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100. Under a medium warming scenario (RCP4.5), the approach projects permafrost soil C losses of 12.2-33.4 Pg C; under a high warming scenario (RCP8.5), the approach projects C losses of 27.9-112.6 Pg C. Projected C losses are roughly linearly proportional to global temperature changes across the two scenarios. These results indicate a global sensitivity of frozen soil C to climate change (γ sensitivity) of -14 to -19 Pg C °C(-1) on a 100 year time scale. For CH4 emissions, our approach assumes a fixed saturated area and that increases in CH4 emissions are related to increased heterotrophic respiration in anoxic soil, yielding CH4 emission increases of 7% and 35% for the RCP4.5 and RCP8.5 scenarios, respectively, which add an additional greenhouse gas forcing of approximately 10-18%. The simplified approach

  17. A novel approach to process carbonate samples for radiocarbon measurements with helium carrier gas

    International Nuclear Information System (INIS)

    Most laboratories prepare carbonates samples for radiocarbon analysis by acid decomposition in evacuated glass tubes and subsequent reduction of the evolved CO2 to graphite in self-made reduction manifolds. This process is time consuming and labor intensive. In this work, we have tested a new approach for the preparation of carbonate samples, where any high-vacuum system is avoided and helium is used as a carrier gas. The liberation of CO2 from carbonates with phosphoric acid is performed in a similar way as it is often done in stable isotope ratio mass spectrometry where CO2 is released with acid in septum sealed tube under helium atmosphere. The formed CO2 is later flushed in a helium flow by means of a double-walled needle mounted from the tubes to the zeolite trap of the automated graphitization equipment (AGE). It essentially replaces the elemental analyzer normally used for the combustion of organic samples. The process can be fully automated from sampling the released CO2 in the septum-sealed tubes with a commercially available auto-sampler to the graphitization with the automated graphitization. The new method yields in low sample blanks of about 50000 years. Results of processed reference materials (IAEA-C2, FIRI-C) are in agreement with their consensus values.

  18. Carbon Biogeochemistry: A Stable Isotope Approach to Trophic Dynamics in an Indian Coastal Ecosystem

    Science.gov (United States)

    Mathukumalli, B.; Alagappan, R.

    2005-12-01

    Stable isotope(δ13C & δ15N) approach was applied to understand carbon biogeochemistry and trophic dynamics in an Indian coastal mangrove wetland. The δ13C and δ15N values of potential nutrient sources (mangrove plant leaves, lichen, sediment and suspended material) and in seven species of consumers (invertebrates) were measured. The value of δ13C and δ15N isotopes of different potential nutrient sources and the consumers determine the sources of nutrients for the invertebrate consumer community of the mangrove. There is a significant variation in the stable carbon in the nutrient sources; however, δ15N signatures were not significantly different among the different potential nutrient sources. Organic matter in the sediments under the mangrove vegetation was characterized by relatively negatively fractionated and moderately high C:N ratios, indicating that mangrove derived organic matter was the principal diet source for the invertebrate consumer communities in the mangrove ecosystem. Invertebrates in the mangrove showed a wide range of δ13C signatures and are enriched relative to the mangrove leaf stable isotope values. Micro-environmental differences certainly drive the variability in the nutrient sources and consumable nature among the different regions of the ecosystem. Therefore, further research is needed to determine whether carbon assimilation is different from one zone to another.

  19. A doping-free approach to carbon nanotube electronics and optoelectronics

    Directory of Open Access Journals (Sweden)

    Lian-Mao Peng

    2012-12-01

    Full Text Available The electronic properties of conventional semiconductor are usually controlled by doping, which introduces carriers into the semiconductor but also distortion and scattering centers to the otherwise perfect lattice, leading to increased scattering and power consumption that becomes the limiting factors for the ultimate performance of the next generation electronic devices. Among new materials that have been considered as potential replacing channel materials for silicon, carbon nanotubes (CNTs have been extensively studied and shown to have all the remarkable electronic properties that an ideal electronic material should have, but controlled doping in CNTs has been proved to be challenging. In this article we will review a doping-free approach for constructing nanoelectronic and optoelectronic devices and integrated circuits. This technique relies on a unique property of CNTs, i.e. high quality ohmic contacts can be made to both the conduction band and valence band of a semiconducting CNT. High performance nanoelectronic and optoelectronic devices have been fabricated using CNTs with this method and performance approach to that of quantum limit. In principle high performance electronic devices and optoelectronic devices can be integrated on the same carbon nanotube with the same footing, and this opens new possibilities for electronics beyond the Moore law in the future.

  20. Synthesis of carbon nanoparticles using one step green approach and their application as mercuric ion sensor

    Energy Technology Data Exchange (ETDEWEB)

    Roshni, V.; Ottoor, Divya, E-mail: divya@chem.unipune.ac.in

    2015-05-15

    Carbon nanoparticles (CNPs) have been evolved as a promising candidate for the metal sensing applications due to their synthesis from naturally occurring and easily available non-toxic molecular precursors by green chemistry. A simple and one step procedure is reported here for the synthesis of CNPs from coconut milk by thermal pyrolysis at a temperature of 120–150 °C for 2–5 min without using any carbonizing or passivating agent. On pyrolysis the coconut oil is separated from the carbon rich residue and the residue when dissolved in water showed blue fluorescence under UV light. The CNPs produced are found to show an emission maximum at 440 nm when excited at 360 nm. Synthesis by green approach makes CNPs a promising substitute for the metal sensing applications. Series of metal ions which have a hazardous impact on the ecological system have been taken for the analysis and it is observed that the fluorescence of CNPs gets remarkably quenched by mercuric ions. Fluorescence quenching was studied using standard Stern–Volmer quenching model. Limit of detection was found to be 16.5 nM Hg{sup 2+} concentration. - Highlights: • Green and economical synthesis of carbon nanoparticles (CNPs) from naturally abundant material. • Coconut milk is used as molecular precursor, which on thermal pyrolysis at 120 °C yielded CNPs. • Highly fluorescent CNPs show an emission maxima of 440 nm when excited at 360 nm. • Application of CNPs for metal ion sensing using fluorescence quenching phenomena. • Hg{sup 2+} is most effectively sensed with a detection limit of 16.5 nM.

  1. Estimation of Soil Carbon Input in France: An Inverse Modelling Approach

    Institute of Scientific and Technical Information of China (English)

    J.MEERSMANS; M.P.MARTIN; E.LACARCE; T.G.ORTON; S.DE BAETS; M.GOURRAT; N.P.A.SABY

    2013-01-01

    Development of a quantitative understanding of soil organic carbon (SOC) dynamics is vital for management of soil to sequester carbon (C) and maintain fertility,thereby contributing to food security and climate change mitigation.There are well-established process-based models that can be used to simulate SOC stock evolution; however,there are few plant residue C input values and those that exist represent a limited range of environments.This limitation in a fundamental model component (i.e.,C input) constrains the reliability of current SOC stock simulations.This study aimed to estimate crop-specific and environment-specific plant-derived soil C input values for agricultural sites in Prance based on data from 700 sites selected from a recently established French soil monitoring network (the RMQS database).Measured SOC stock values from this large scale soil database were used to constrain an inverse RothC modelling approach to derive estimated C input values consistent with the stocks.This approach allowed us to estimate significant crop-specific C input values (P < 0.05) for 14 out of 17 crop types in the range from 1.84 ± 0.69 t C ha-1 year-1 (silage corn) to 5.15 ± 0.12 t C ha-1 year-1 (grassland/pasture).Furthermore,the incorporation of climate variables improved the predictions.C input of 4 crop types could be predicted as a function of temperature and 8 as a function of precipitation.This study offered an approach to meet the urgent need for crop-specific and environment-specific C input values in order to improve the reliability of SOC stock prediction.

  2. Synthesis of carbon fibre-reinforced, silicon carbide composites by soft-solution approach

    Indian Academy of Sciences (India)

    N Padmavathi; P Ghosal; N Eswara Prasad; J Subramanyam; K K Ray

    2012-08-01

    The aim of the present work centers on synthesizing and characterizing carbon fibre (Cf) reinforced, silicon carbide matrix composites which are considered to have potential applications in aerospace and automobile industry. A series of composites, namely the Cf-SiC, Cf-(SiC+ZrC), Cf-(SiC+ZrB2), and Cf-(SiC+ZrO2), have been prepared by a proposed soft-solution approach. This approach involves the use of water-soluble precursors of colloidal silica, sucrose, zirconium oxychloride, and boric acid as sources of silica, carbon, zirconia, and boron oxide, respectively to achieve the desired matrices through drying, carbonization and carbothermal reduction. The prepared powders and the composites were characterized by thermal analysis, X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses to assess the phase formation and microstructure of the materials, apart from assessment of their tensile properties. The study shows that the soft-solution process yields matrices with finer crystallite sizes, having homogeneous distribution of the constituent phases of either the powders or of the composite matrices. The role of the additional phases on the tensile properties of the composites has been discussed using consideration of thermal stresses at fibre-matrix interface; whereas the role of the carbothermal reduction temperature in determining these properties has been explained using the interfacial characteristics of the fibre-matrix. Addition of ZrO2 in the matrix of SiC has shown to improve the properties of Cf-SiC composites considerably. The results of this investigation unambiguously demonstrate that aqueous solution-based processing can be used for fabrication of these composites in relatively shorter time in an environmental friendly manner without using any expensive equipment. The approach is capable of yielding composites with different phases in the matrix by simple variation of

  3. The hidden costs of fossil power generation in Indonesia: A reduction approach through low carbon society

    Directory of Open Access Journals (Sweden)

    Muhammad Ery Wijaya

    2010-03-01

    Full Text Available Energy production and consumption is always accompanied with environmental and societal issues. Electricity as onefinal energy form plays an important role in people’s activities. However, the electric utilities have focused on producingelectricity in abundance and with an affordable price. The production of electricity results in undesirable emissions and environmental effects called externalities. This paper assesses the externality cost of electricity production in Indonesia by using the life cycle inventory analysis approach. In 2025, the results show that the total external costs according to the government plan are 42 billion US$. In addition, low carbon society behavior will be introduced into the Indonesian society to reducethe externality cost in the long term Indonesian electricity expansion planning. The results of low carbon society actionsshow that in the long term the Indonesian electricity expansion planning of 34.6 TWh of electricity demand and 7.3 GW of installed capacity can be reduced from these actions. Finally, at the end of the period, these actions are successful, and reducing the total external cost by 2 billion US$.

  4. Influencing attitudes toward carbon capture and sequestration: a social marketing approach.

    Science.gov (United States)

    Wong-Parodi, Gabrielle; Dowlatabadi, Hadi; McDaniels, Tim; Ray, Isha

    2011-08-15

    Carbon capture and sequestration (CCS), while controversial, is seen as promising because it will allow the United States to continue using its vast fossil fuel resources in a carbon-constrained world. The public is an important stakeholder in the national debate about whether or not the U.S. should include CCS as a significant part of its climate change strategy. Understanding how to effectively engage with the public about CCS has become important in recent years, as interest in the technology has intensified. We argue that engagement efforts should be focused on places where CCS will first be deployed, i.e., places with many "energy veteran" (EV) citizens. We also argue that, in addition to information on CCS, messages with emotional appeal may be necessary in order to engage the public. In this paper we take a citizen-guided social marketing approach toward understanding how to (positively or negatively) influence EV citizens' attitudes toward CCS. We develop open-ended interview protocols, and a "CCS campaign activity", for Wyoming residents from Gillette and Rock Springs. We conclude that our participants believed expert-informed CCS messages, embedded within an emotionally self-referent (ESR) framework that was relevant to Wyoming, to be more persuasive than the expert messages alone. The appeal to core values of Wyomingites played a significant role in the citizen-guided CCS messages. PMID:21728279

  5. Carbon dot based non enzymatic approach for the detection and estimation of glucose in blood serum

    Science.gov (United States)

    Shanti Krishna, A.; Nair, Priya A.; Radhakumary, C.; Sreenivasan, K.

    2016-05-01

    In this study we generated a simple, reliable and selective approach based on carbon dots (CDs) and 4-cyanophenylboronic acid (CPBA) for blood glucose sensing. The methodology relies on the quenching of the emission of CDs by CPBA followed by its recovery by glucose. The system consisting of CDs and CPBA was characterised by Fourier transform infra red spectrum, transmissions electron microscopic, dynamic light scattering instrument, UV–visible and fluorescence techniques. The response of the probe, CD-BA in presence of different concentrations of glucose was assessed. Linear range was obtained for glucose concentrations ranging from 1 to 30 mM. Interferences by other saccharides and various biomolecules coexisting in blood serum were negligible. The chemo sensor thus developed has been successfully used for the estimation of glucose in human blood serum. The system being sensitive, efficient and easy to perform is a promising platform for blood glucose sensing.

  6. Quantifying ecosystem carbon losses and gains following development in New England: A combined field, modeling, and remote sensing approach

    Science.gov (United States)

    Raciti, S. M.; Hutyra, L.; Briber, B. M.; Dunn, A. L.; Friedl, M. A.; Woodcock, C.; Zhu, Z.; Olofsson, P.

    2013-12-01

    If current trends continue, the world's urban population may double and urban land area may quadruple over the next 50 years. Despite the rapid expansion of urban areas, the trajectories of carbon losses and gains following development remain poorly quantified. We are using a combination of field measurements, modeling, and remote sensing to advance our ability to measure and monitor trajectories of ecosystem carbon over space and time. To characterize how carbon stocks change across urban-to-rural gradients, we previously established field plots to survey live and dead tree biomass, tree canopy, soil and foliar carbon and nitrogen concentrations, and a range of landscape characteristics (Raciti et al. 2012). In 2013, we extended our field sampling to focus specifically on places that experienced land use and land cover change over the past 35 years. This chronosequence approach was informed by Landsat time series (1982-present) and property records (before 1982). The Landsat time series approach differs from traditional remote-sensing-based land use change detection methods because it leverages the entire Landsat archive of imagery using a Fourier fitting approach (Zhu et al. 2012). The result is a temporally and spatially continuous map of land use and land cover change across the study region. We used these field and remote sensing data to inform a carbon bookkeeping model that estimates changes in past and potential future carbon stocks over time. Here we present preliminary results of this work for eastern Massachusetts.

  7. LIFE CLIMATREE project: A novel approach for accounting and monitoring carbon sequestration of tree crops and their potential as carbon sink areas

    Science.gov (United States)

    Stergiou, John; Tagaris, Efthimios; -Eleni Sotiropoulou, Rafaella

    2016-04-01

    Climate Change Mitigation is one of the most important objectives of the Kyoto Convention, and is mostly oriented towards reducing GHG emissions. However, carbon sink is retained only in the calculation of the forests capacity since agricultural land and farmers practices for securing carbon stored in soils have not been recognized in GHG accounting, possibly resulting in incorrect estimations of the carbon dioxide balance in the atmosphere. The agricultural sector, which is a key sector in the EU, presents a consistent strategic framework since 1954, in the form of Common Agricultural Policy (CAP). In its latest reform of 2013 (reg. (EU) 1305/13) CAP recognized the significance of Agriculture as a key player in Climate Change policy. In order to fill this gap the "LIFE ClimaTree" project has recently founded by the European Commission aiming to provide a novel method for including tree crop cultivations in the LULUCF's accounting rules for GHG emissions and removal. In the framework of "LIFE ClimaTree" project estimation of carbon sink within EU through the inclusion of the calculated tree crop capacity will be assessed for both current and future climatic conditions by 2050s using the GISS-WRF modeling system in a very fine scale (i.e., 9km x 9km) using RCP8.5 and RCP4.5 climate scenarios. Acknowledgement: LIFE CLIMATREE project "A novel approach for accounting and monitoring carbon sequestration of tree crops and their potential as carbon sink areas" (LIFE14 CCM/GR/000635).

  8. Experimental approaches to marine and meteoric dissolution-to-repreciptiation cycles of fine-grained marine carbonate sediments

    Science.gov (United States)

    Immenhauser, Adrian; Buhl, Dieter; Riechelmann, Sylvia; Kwiecien, Ola; Lokier, Stephen; Neuser, Rolf

    2016-04-01

    Fine-grained carbonate (carbonate ooze), or microcrystalline carbonate (micrite), its lithified counterpart, forms a main constituent of limestones throughout much of Earth's history. Fine-grained carbonates are deposited below the permanent fair-weather wave base in neritic lagoonal environments or below the storm-wave base in basinal settings. The origin of components forming these fine-grained carbonates often remains poorly understood and represents a major challenge in carbonate sedimentology, particularly when these materials are used as carbonate archives (bulk micrite geochemistry). Here we present a novel experimental approach exposing natural, fine-grained carbonate sediments to dissolution-reprecipitation cycles under non-sterile conditions that mimick earth-surface conditions. In a first stage, the experiment simulated subaerial exposure of an ooid (aragonite) shoal and leaching and carbonate dissolution under meteoric phreatic conditions. In a second stage, CO2 was added to the experimental fluid (natural rainwater) representing soil-zone activity. In a third stage, partly dissolved (micro-karstified) sediments were exposed to marine phreatic conditions simulating renewed flooding of the shoal carbonates. During the third stage, precipitation was induced by degassing the CO2 in the fluid with N2. Degassing induced nucleation and growth of a diagenetic inorganic aragonite (and subordinate calcite) phase upon the surface of carbonate particles. The outcome of these first experiments is promising. The CO2 concentration of the fluid and the air are low under atmospheric conditions and increase as expected due to adding CO2 to the experiment resulting in a lower pH. Carbonate dissolution increases conductivity, alkalinity, and calcium concentration reaching a plateau at the end of the first experimental phase. Small surficial damages to ooids represent zones of weakness and form the preferred sites of dissolution leading to a deepening and widening of these

  9. Global assessment of soil organic carbon stocks and spatial distribution of histosols: the Machine Learning approach

    Science.gov (United States)

    Hengl, Tomislav

    2016-04-01

    Preliminary results of predicting distribution of soil organic soils (Histosols) and soil organic carbon stock (in tonnes per ha) using global compilations of soil profiles (about 150,000 points) and covariates at 250 m spatial resolution (about 150 covariates; mainly MODIS seasonal land products, SRTM DEM derivatives, climatic images, lithological and land cover and landform maps) are presented. We focus on using a data-driven approach i.e. Machine Learning techniques that often require no knowledge about the distribution of the target variable or knowledge about the possible relationships. Other advantages of using machine learning are (DOI: 10.1371/journal.pone.0125814): All rules required to produce outputs are formalized. The whole procedure is documented (the statistical model and associated computer script), enabling reproducible research. Predicted surfaces can make use of various information sources and can be optimized relative to all available quantitative point and covariate data. There is more flexibility in terms of the spatial extent, resolution and support of requested maps. Automated mapping is also more cost-effective: once the system is operational, maintenance and production of updates are an order of magnitude faster and cheaper. Consequently, prediction maps can be updated and improved at shorter and shorter time intervals. Some disadvantages of automated soil mapping based on Machine Learning are: Models are data-driven and any serious blunders or artifacts in the input data can propagate to order-of-magnitude larger errors than in the case of expert-based systems. Fitting machine learning models is at the order of magnitude computationally more demanding. Computing effort can be even tens of thousands higher than if e.g. linear geostatistics is used. Many machine learning models are fairly complex often abstract and any interpretation of such models is not trivial and require special multidimensional / multivariable plotting and data mining

  10. Thermo-sensitive imprinted polymer embedded carbon dots using epitope approach.

    Science.gov (United States)

    Li, Dong-Yan; Zhang, Xue-Mei; Yan, Yun-Jing; He, Xi-Wen; Li, Wen-You; Zhang, Yu-Kui

    2016-05-15

    A new type of thermo-sensitive receptor carbon dots/SiO2/molecularly imprinted polymer (CDs/SiO2/MIP) was prepared by surface imprinting procedure and the epitope approach. The synthetic CDs/SiO2/MIP was able to selectively capture target protein with fluorescence quenching via the special interaction between them and the recognition cavities. The receptor exhibited the linear fluorescence quenching to cytochrome c (cyt c) in the range of 0.1-40 μM, and the detection limit was 89 nM. The precision for five replicate detection of cyt c at 20 μM was 3.11%. Moreover, the receptor owned the temperature-sensitive element that allowed for swelling and shrinking in response to temperature changes to realize recognition of the target cytochrome c. The proposed strategy revealed the feasibility of fabrication of a thermo-sensitive imprinted polymer based on CDs and surface imprinting procedure and the epitope approach. PMID:26706940

  11. A Molecular Surface Functionalization Approach to Tuning Nanoparticle Electrocatalysts for Carbon Dioxide Reduction.

    Science.gov (United States)

    Cao, Zhi; Kim, Dohyung; Hong, Dachao; Yu, Yi; Xu, Jun; Lin, Song; Wen, Xiaodong; Nichols, Eva M; Jeong, Keunhong; Reimer, Jeffrey A; Yang, Peidong; Chang, Christopher J

    2016-07-01

    Conversion of the greenhouse gas carbon dioxide (CO2) to value-added products is an important challenge for sustainable energy research, and nanomaterials offer a broad class of heterogeneous catalysts for such transformations. Here we report a molecular surface functionalization approach to tuning gold nanoparticle (Au NP) electrocatalysts for reduction of CO2 to CO. The N-heterocyclic (NHC) carbene-functionalized Au NP catalyst exhibits improved faradaic efficiency (FE = 83%) for reduction of CO2 to CO in water at neutral pH at an overpotential of 0.46 V with a 7.6-fold increase in current density compared to that of the parent Au NP (FE = 53%). Tafel plots of the NHC carbene-functionalized Au NP (72 mV/decade) vs parent Au NP (138 mV/decade) systems further show that the molecular ligand influences mechanistic pathways for CO2 reduction. The results establish molecular surface functionalization as a complementary approach to size, shape, composition, and defect control for nanoparticle catalyst design. PMID:27322487

  12. Bottom-up catalytic approach towards nitrogen-enriched mesoporous carbons/sulfur composites for superior Li-S cathodes.

    Science.gov (United States)

    Sun, Fugen; Wang, Jitong; Chen, Huichao; Qiao, Wenming; Ling, Licheng; Long, Donghui

    2013-01-01

    We demonstrate a sustainable and efficient approach to produce high performance sulfur/carbon composite cathodes via a bottom-up catalytic approach. The selective oxidation of H2S by a nitrogen-enriched mesoporous carbon catalyst can produce elemental sulfur as a by-product which in-situ deposit onto the carbon framework. Due to the metal-free catalytic characteristic and high catalytic selectivity, the resulting sulfur/carbon composites have almost no impurities that thus can be used as cathode materials with compromising battery performance. The layer-by-layer sulfur deposition allows atomic sulfur binding strongly with carbon framework, providing efficient immobilization of sulfur. The nitrogen atoms doped on the carbon framework can increase the surface interactions with polysulfides, leading to the improvement in the trapping of polysulfides. Thus, the composites exhibit a reversible capacity of 939 mAh g(-1) after 100 cycles at 0.2 C and an excellent rate capability of 527 mAh g(-1) at 5 C after 70 cycles.

  13. Biomarker and molecular isotope approaches to deconvolve the terrestrial carbon isotope record: modern and Eocene calibrations

    Science.gov (United States)

    Diefendorf, A. F.; Freeman, K. H.; Wing, S.; Currano, E. D.

    2010-12-01

    Climate, biome, and plant community are important predictors of carbon isotope patterns recorded in leaves and leaf waxes. However, signatures recorded by terrestrial organic carbon and lipids that have mixed floral sources (e.g., n-alkanes) potentially reflect both plant community changes and climate. More taxonomically specific proxies for plants (i.e., di- and tri-terpenoids for conifers and angiosperms, respectively), can help to resolve the relative influences of changing community and climate, provided differences in biomarker production and lipid biosynthetic fractionation among plants can be better constrained. We present biomarker abundance and carbon isotope values for lipids from leaves, branches and bark of 44 tree species, representing 21 families including deciduous and evergreen conifers and angiosperms. n-alkane production differs greatly between conifer and angiosperm leaves. Both deciduous and evergreen angiosperms make significantly more n-alkanes than conifers, with n-alkanes not detected in over half of the conifers in our study. Terpenoid abundances scale strongly with leaf habit: evergreen species have significantly higher abundances. We combine these relative differences in lipid production with published estimates of fluxes for leaf litter from conifer and angiosperm trees to develop a new proxy approach for estimating paleo plant community inputs to ancient soils and sediments. To test our modern calibration results, we have evaluated n-alkanes and terpenoids from laterally extensive (~18 km) carbonaceous shales and mudstones in Eocene sediments (52.6 Ma) at Fifteenmile Creek in the Bighorn Basin (WY, USA). Our terpenoid-based proxy predicts on average a 40% conifer community, which is remarkably close in agreement with a fossil-based estimate of 36%. n-alkane carbon isotope fractionation (leaf-lipid) differs among plant types, with conifer n-alkanes about 2-3‰ 13C enriched relative to those in angiosperms. Since conifer leaves are

  14. Recovery Act: Multi-Objective Optimization Approaches for the Design of Carbon Geological Sequestration Systems

    Energy Technology Data Exchange (ETDEWEB)

    Bau, Domenico

    2013-05-31

    The main objective of this project is to provide training opportunities for two graduate students in order to improve the human capital and skills required for implementing and deploying carbon capture and sequestration (CCS) technologies. The graduate student effort will be geared towards the formulation and implementation of an integrated simulation-optimization framework to provide a rigorous scientific support to the design CCS systems that, for any given site: (a) maximize the amount of carbon storage; (b) minimize the total cost associated with the CCS project; (c) minimize the risk of CO2 upward leakage from injected formations. The framework will stem from a combination of data obtained from geophysical investigations, a multiphase flow model, and a stochastic multi-objective optimization algorithm. The methodology will rely on a geostatistical approach to generate ensembles of scenarios of the parameters that are expected to have large sensitivities and uncertainties on the model response and thus on the risk assessment, in particular the permeability properties of the injected formation and its cap rock. The safety theme will be addressed quantitatively by including the risk of CO2 upward leakage from the injected formations as one the objectives that should be minimized in the optimization problem. The research performed under this grant is significant to academic researchers and professionals weighing the benefits, costs, and risks of CO2 sequestration. Project managers in initial planning stages of CCS projects will be able to generate optimal tradeoff surfaces and with corresponding injection plans for potential sequestration sites leading to cost efficient preliminary project planning. In addition, uncertainties concerning CCS have been researched. Uncertainty topics included Uncertainty Analysis of Continuity of Geological Confining Units using Categorical Indicator Kriging (CIK) and the Influence of Uncertain Parameters on the Leakage of CO2 to

  15. An integrated ecosystem approach for assessing the potential role of cultivated bivalve shells as part of the carbon trading system

    DEFF Research Database (Denmark)

    Filgueira, Ramón; Byron, C.J.; Comeau, L.A.;

    2015-01-01

    , is needed to provide a rigorous assessment of the role of bivalve mariculture in the CO2 cycle. On the other hand, the discussion about the inclusion of shells of cultured bivalves into the carbon trading system should be framed in the context of ecosystem goods and services. Humans culture bivalves...... and shell when constructing a specific CO2 budget for shells for evaluating the potential of including bivalve shells, and not the whole organism, in the carbon trading system. Concluding, an integrated ecosystem approach as well as an understanding of the ecosystems goods and services of bivalve......The role of bivalve mariculture in the CO2 cycle has been commonly evaluated as the balance between respiration, shell calcium carbonate sequestration and CO2 release during biogenic calcification. However, this approach neglects the ecosystem implications of cultivating bivalves at high densities...

  16. An integrated ecosystem approach for assessing the potential role of cultivated bivalve shells as part of the carbon trading system

    NARCIS (Netherlands)

    Filgueira, R.; Byron, C.J.; Comeau, L.A.; Jansen, H.M.; Smaal, A.C.

    2015-01-01

    The role of bivalve mariculture in the CO2 cycle has been commonly evaluated as the balance between respiration, shell calcium carbonate sequestration and CO2 release during biogenic calcification. However, this approach neglects the ecosystem implications of cultivating bivalves at high densities,

  17. An integrated approach for high spatial resolution mapping of water and carbon fluxes using multi-sensor data

    Science.gov (United States)

    In the last few years, modeling of surface processes, such as water and carbon balances, vegetation growth and energy budgets, has focused on integrated approaches that combine aspects of hydrology, biology and meteorology into unified analyses. In this context, remotely sensed data often have a cor...

  18. A comparison of different inverse carbon flux estimation approaches for application on a regional domain

    NARCIS (Netherlands)

    Tolk, L. F.; Dolman, A. J.; Meesters, A. G. C. A.; Peters, W.

    2011-01-01

    We have implemented six different inverse carbon flux estimation methods in a regional carbon dioxide (CO2) flux modeling system for the Netherlands. The system consists of the Regional Atmospheric Mesoscale Modeling System (RAMS) coupled to a simple carbon flux scheme which is run in a coupled fash

  19. A structured approach for selecting carbon capture process models : A case study on monoethanolamine

    NARCIS (Netherlands)

    van der Spek, Mijndert; Ramirez, Andrea

    2014-01-01

    Carbon capture and storage is considered a promising option to mitigate CO2 emissions. This has resulted in many R&D efforts focusing at developing viable carbon capture technologies. During carbon capture technology development, process modeling plays an important role. Selecting an appropriate pro

  20. New approaches for carbon nanotubes-based biosensors and their application to cell culture monitoring.

    Science.gov (United States)

    Boero, Cristina; Olivo, Jacopo; De Micheli, Giovanni; Carrara, Sandro

    2012-10-01

    Amperometric biosensors are complex systems and they require a combination of technologies for their development. The aim of the present work is to propose a new approach in order to develop nanostructured biosensors for the real-time detection of multiple metabolites in cell culture flasks. The fabrication of five Au working electrodes onto silicon substrate is achieved with CMOS compatible microtechnology. Each working electrode presents an area of 0.25 mm², so structuration with carbon nanotubes and specific functionalization are carried out by using spotting technology, originally developed for microarrays and DNA printing. The electrodes are characterized by cyclic voltammetry and compared with commercially available screen-printed electrodes. Measurements are carried out under flow conditions, so a simple fluidic system is developed to guarantee a continuous flow next to the electrodes. The working electrodes are functionalized with different enzymes and calibrated for the real-time detection of glucose, lactate, and glutamate. Finally, some tests are performed on surnatant conditioned medium sampled from neuroblastoma cells (NG-108 cell line) to detect glucose and lactate concentration after 72 hours of cultivation. The developed biosensor for real-time and online detection of multiple metabolites shows very promising results towards circuits and systems for cell culture monitoring. PMID:23853234

  1. A mass balance approach to assess carbon dioxide evolution during erosional events

    International Nuclear Information System (INIS)

    The accelerated greenhouse effect and the degradation of land resources by water and wind erosion are two major, yet interrelated global environmental challenges. Accelerated decomposition of soil organic carbon (SOC) in cultivated soils results in decline in SOC stocks over time and also contributes to increased levels of CO2 in the atmosphere. Off-site transport of SOC in runoff waters during erosional events also contributes to SOC depletion, but there is a paucity of data in the literature documenting erosional SOC losses and the fate of eroded SOC. In this paper, we present a mass balance approach to compute CO2 evolved from mineralization of SOC during transport and deposition of eroded soils. Erosion-induced CO2 emission rates ranging between 6 and 52 g C m-2 yr-1 were computed using data on SOC stocks and dynamics from a series of long-term experiments conducted across a range of ecological regions. For the cropland of the world, we estimated an annual flux of 0.37 Pg CO2 -C to the atmosphere due to water erosion. This flux is significant and suggests that water erosion must be taken into consideration when constructing global and regional C budgets. Through its contribution to atmospheric CO2 increase, water erosion can have a positive feedback on the accelerated greenhouse effect. (author)

  2. A robust approach to the design of an electromagnetic shield based on pyrolitic carbon

    Science.gov (United States)

    Lamberti, Patrizia; Kuzhir, Polina; Tucci, Vincenzo

    2016-07-01

    A robust approach to the design of an electromagnetic shield based on ultra-thin pyrolytic carbon (PyC, 5 ÷ 110 nm) films is proposed. Finite Element Method (FEM) simulations and Monte Carlo based tolerance analysis are used to show that even a deviation of 15 ÷ 20% from the nominal values of the most important design parameters of the PyC film, i.e. its thickness and sheet resistance, does not significantly affect the wanted level of electromagnetic interference shielding efficiency (EMI SE). The ranges of the SE show that EMI shield based on PyC film is characterized by a robust behavior with respect to the variation of such parameters due to the production processes. Therefore, since the PyC can be produced on a scalable basis, is chemically inert, significantly transparent in the visible range and can be deposited onto both metal and dielectric substrates, including flexible polymers, it may be appropriate for the highly demanding technological needs associated to the graphene revolution and can be developed from laboratory to mass production applications.

  3. Developing an approach for first-principles catalyst design: application to carbon-capture catalysis.

    Science.gov (United States)

    Kulik, Heather J; Wong, Sergio E; Baker, Sarah E; Valdez, Carlos A; Satcher, Joe H; Aines, Roger D; Lightstone, Felice C

    2014-02-01

    An approach to catalyst design is presented in which local potential energy surface models are first built to elucidate design principles and then used to identify larger scaffold motifs that match the target geometries. Carbon sequestration via hydration is used as the model reaction, and three- and four-coordinate sp(2) or sp(3) nitrogen-ligand motifs are considered for Zn(II) metals. The comparison of binding, activation and product release energies over a large range of interaction distances and angles suggests that four-coordinate short Zn(II)-Nsp(3) bond distances favor a rapid turnover for CO2 hydration. This design strategy is then confirmed by computationally characterizing the reactivity of a known mimic over a range of metal-nitrogen bond lengths. A search of existing catalysts in a chemical database reveals structures that match the target geometry from model calculations, and subsequent calculations have identified these structures as potentially effective for CO2 hydration and sequestration. PMID:24508957

  4. Developing an approach for first-principles catalyst design: application to carbon-capture catalysis.

    Science.gov (United States)

    Kulik, Heather J; Wong, Sergio E; Baker, Sarah E; Valdez, Carlos A; Satcher, Joe H; Aines, Roger D; Lightstone, Felice C

    2014-02-01

    An approach to catalyst design is presented in which local potential energy surface models are first built to elucidate design principles and then used to identify larger scaffold motifs that match the target geometries. Carbon sequestration via hydration is used as the model reaction, and three- and four-coordinate sp(2) or sp(3) nitrogen-ligand motifs are considered for Zn(II) metals. The comparison of binding, activation and product release energies over a large range of interaction distances and angles suggests that four-coordinate short Zn(II)-Nsp(3) bond distances favor a rapid turnover for CO2 hydration. This design strategy is then confirmed by computationally characterizing the reactivity of a known mimic over a range of metal-nitrogen bond lengths. A search of existing catalysts in a chemical database reveals structures that match the target geometry from model calculations, and subsequent calculations have identified these structures as potentially effective for CO2 hydration and sequestration.

  5. Phenol-stacked carbon nanotubes: A new approach to genomic DNA isolation from plants

    Directory of Open Access Journals (Sweden)

    Farhad Nazarian-Firouzabadi

    2014-09-01

    Full Text Available Extraction of intact quality DNA from plant tissues, especially those rich in secondary metabolites, is often challenging. Literally, hundreds of different DNA isolation protocols from various plant species have been published over the last decades. Although many commercial DNA isolation kits are convenient and designed to be safe, their cost and availability cause limitations in small molecular labs in many developing countries. In nearly all protocols and DNA isolation kits, phenol and chloroform are used to precipitate various classes of impurities. However, phenol is partially soluble in water, resulting in the co-existence of proteins in upper (aqueous phases. This phenomenon results in the contamination of the nucleic acids and low quality DNA. Nanotechnology advances have helped many areas of molecular biology such as the development of new diagnosis and purification kits. In this study, for the first time, we report a different approach to isolate DNA from plants based on carbon nanotubes (CNTs. The results show that the phenol reagent stack on CNTs can effectively remove proteins, polysaccharides and other polyphenol constituents. The A260/A280nm absorbance ratios of isolated DNA samples were 1.9 and 1.8 for chamomile and opium plants, respectively, indicating the high purity of the isolated DNA. DNA yield was more than two times the standard Doyle and Doyle method. Furthermore, the isolated DNA proved amenable to PCR amplification, using Random Amplified Polymorphic DNA (RAPD analysis.

  6. A molecular-based approach to the thermodynamics of aqueous solutions: binary mixture of water and carbon dioxide

    International Nuclear Information System (INIS)

    A simple model and theory of molecular fluids is applied to a binary mixture of water and carbon dioxide. An approach based on the perturbation theory is followed using a reference system of so-called pseudo-hard bodies for water and hard triatomics for carbon dioxide. Pseudo-hard bodies bear the traits of the non-additive nature of association supplementing the common excluded volume effect. The reference term is parametrized using Monte Carlo simulation data on the compressibility factor. After adding a simple mean-field term to the reference equation, fluid phase equilibria are qualitatively reproduced. (paper)

  7. Non-covalently Functionalized Fluorescent Carbon Nanotubes: A Supramolecular Approach of Selective Zinc Ions Sensing in Living Cells%Non-covalently Functionalized Fluorescent Carbon Nanotubes: A Supramolecular Approach of Selective Zinc Ions Sensing in Living Cells

    Institute of Scientific and Technical Information of China (English)

    刘玉萍; 陈湧; 张宁; 刘育

    2012-01-01

    A fluorescent cyclodextrin/carbon nanotube assembly was easily constructed through the non-covalent attach- ment of adamantanylpyrene on carbon nanotube and the following association of cyclodextrin derivative bearing fluorescent substituent, and its structure was fully characterized by UV/Vis/NIR spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and atomic force microscopy. Fluorescence spectroscopic and fluorescence microscopic studies showed that the resultant non-covalently functionalized fluo- rescent nanotube could be used as a highly selective fluorescent probe for Zn2+ in both water and living cells. Without carbon nanotube, the fluorescence probe was unable to enter the cell but only anchored on the cell mem- brane. This approach will overcome the disadvantage of many spectral sensors that are unable to enter living cells and greatly improve the application of naotube-related supramolecular architecture in nanoscience and technology.

  8. On the structural and mechanical properties of Fe-filled carbon nanotubes: a computer simulation approach.

    Science.gov (United States)

    Soldano, G; Mariscal, M M

    2009-04-22

    The structural and mechanical properties of single-and multi-walled carbon nanotubes filled with iron nanowires are studied using a recent parameterization of the modified embedded atom model. We have analyzed the effect of different crystal structures of iron (bcc and fcc) inside carbon nanotubes of different topographies. We have computed strain energy versus strain curves for pure systems: Fe nanowires, carbon and Fe-filled carbon nanotubes. A noticeable difference is found when these monatomic systems are joined to form iron-capped nanowires and where multi-layers of graphite are added to the nanotubes.

  9. 水淹层地层水电阻率的二步确定方法%Two-step Determination Method of Formation Water Resistivity in Water-flooded Zone

    Institute of Scientific and Technical Information of China (English)

    张占松; 张超谟

    2011-01-01

    通过水淹层地层水电阻率变化规律的分析,认为水淹层地层水电阻率的变化具有分段变化特征,可以近似地分段取值.通过水淹层测井响应特征及变化规律分析,提出一种二步确定水淹层地层水电阻率的方法.确定水淹层测井电阻率的相对减小量、自然电位曲线基线偏移量和测井曲线形态特征,根据这些特征选择地层水电阻率的值.在A油田的实际应用证明该方法是有效的.%The formation water resistivity in water-flooded zone is an important parameter in the saturation calculation and reservoir evaluation. With the analysis of the formation water resistivity changes in water-flooded zone, it is proved that there are staged change characteristics of formation water resistivity in water-flooded zone, and we can choose resistivity values depending on the water-flooded stages. According to the analysis of the characteristics and changes of logging responses, a two-step determination method of the formation water resistivity in water-flooded zone has been proposed. First, the relative diminution value of water-flooded reservoir, base offset of spontaneous potential curve and well logging curve shape are determinated. Secondly, according to these characteristics, the formation water resistivity is selected. This method has been applied successfully to A oilfield.

  10. Experimental design: application to the development of a treatment to inhibit the deposition of barium sulfate liable to be formed in enhanced oil recovery by waterflooding

    Energy Technology Data Exchange (ETDEWEB)

    Messaoudene, N. (Sonatrach, Boumerdes (Algeria)); Puech-Costes, E.; Maurette, M.T. (Toulouse-3 Univ., 31 (France)); Girou, A. (Institut National des Sciences Appliquees (INSA), 31 - Toulouse (France)); Roque, C. (Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France))

    For technical and economic reasons, waterflooding is the most widely-used method in enhanced oil recovery. In many situations, unfortunately, the formation water is incompatible with the injection water. The deposits and corrosion induced by the various reactions of this incompatibility cause irreversible damage, which is especially dangerous for the reservoir rock and the downhole and surface production facilities. This study is concerned exclusively with barium sulfate deposits liable to occur in surface production facilities by the mixing of injection water loaded with sulfate (1300 mg.l[sup -1]) with a formation water with a high barium concentration (1200 mg.l[sup -1]). 6 refs., 6 figs., 7 tabs.

  11. A simplified, data-constrained approach to estimate the permafrost carbon-climate feedback: The PCN Incubation-Panarctic Thermal (PInc-PanTher) Scaling Approach

    Science.gov (United States)

    Koven, C. D.; Schuur, E.; Schaedel, C.; Bohn, T. J.; Burke, E.; Chen, G.; Chen, X.; Ciais, P.; Grosse, G.; Harden, J. W.; Hayes, D. J.; Hugelius, G.; Jafarov, E. E.; Krinner, G.; Kuhry, P.; Lawrence, D. M.; MacDougall, A.; Marchenko, S. S.; McGuire, A. D.; Natali, S.; Nicolsky, D.; Olefeldt, D.; Peng, S.; Romanovsky, V. E.; Schaefer, K. M.; Strauss, J.; Treat, C. C.; Turetsky, M. R.

    2015-12-01

    We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation-Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soil temperature. The trajectories are determined according to a 3-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100.

  12. Evaluating ultrasound signals of carbon steel fatigue testing using signal analysis approaches

    Institute of Scientific and Technical Information of China (English)

    M.M.Padzi; S.Abdullah; M.Z.Nuawi; S.M.Beden; Z.M.Nopiah

    2014-01-01

    The application of ultrasound techniques to monitor the condition of structures is becoming more prominent because these techniques can detect the early symptoms of defects such as cracks and other defects. The early detection of defects is of vital importance to avoid major failures with catastrophic consequences. An assessment of an ultrasound technique was used to investigate fatigue damage behaviour. Fatigue tests were performed according to the ASTM E466-96 standard with the attachment of an ultrasound sensor to the test specimen. AISI 1045 carbon steel was used due to its wide application in the automotive industry. A fatigue test was performed under constant loading stress at a sampling frequency of 8 Hz. Two sets of data acquisition systems were used to collect the fatigue strain signals and ultrasound signals. All of the signals were edited and analysed using a signal processing approach. Two methods were used to evaluate the signals, the integrated Kurtosis-based algorithm for z-filter technique (I-kaz) and the short-time Fourier transform (STFT). The fatigue damage behaviour was observed from the initial stage until the last stage of the fatigue test. The results of the I-kaz coefficient and the STFT spectrum were used to explain and describe the behaviour of the fatigue damage. I-kaz coefficients were ranged from 60 to 61 for strain signals and ranged from 5 to 76 for ultrasound signals. I-kaz values tend to be high at failure point due to high amplitude of respective signals. STFT spectrogram displays the colour intensity which represents the damage severity of the strain signals. I-kaz technique is found very useful and capable in assessing both stationary and non-stationary signals while STFT technique is suitable only for non-stationary signals by displaying its spectrogram.

  13. A thermodynamic approach to assess organic solute adsorption onto activated carbon in water

    KAUST Repository

    De Ridder, David J.

    2012-08-01

    In this paper, the hydrophobicity of 13 activated carbons is determined by various methods; water vapour adsorption, immersion calorimetry, and contact angle measurements. The quantity and type of oxygen-containing groups on the activated carbon were measured and related to the methods used to measure hydrophobicity. It was found that the water-activated carbon adsorption strength (based on immersion calorimetry, contact angles) depended on both type and quantity of oxygen-containing groups, while water vapour adsorption depended only on their quantity. Activated carbon hydrophobicity measurements alone could not be related to 1-hexanol and 1,3-dichloropropene adsorption. However, a relationship was found between work of adhesion and adsorption of these solutes. The work of adhesion depends not only on activated carbon-water interaction (carbon hydrophobicity), but also on solute-water (solute hydrophobicity) and activated carbon-solute interactions. Our research shows that the work of adhesion can explain solute adsorption and includes the effect of hydrogen bond formation between solute and activated carbon. © 2012 Elsevier Ltd. All rights reserved.

  14. Experimental studies of low salinity water flooding in carbonate reservoirs: A new promising approach

    DEFF Research Database (Denmark)

    Zahid, Adeel; Shapiro, Alexander; Skauge, Arne

    2012-01-01

    reservoirs. In this paper, we have experimentally investigated the oil recovery potential of low salinity water flooding for carbonate rocks. We used both reservoir carbonate and outcrop chalk core plugs. The flooding experiments were carried out initially with the seawater, and afterwards additional oil...... additional oil recovery can be achieved when successively flooding composite carbonate core plugs with various diluted versions of seawater. The experimental data on carbonates is very limited, so more data and better understanding of the mechanisms involved is needed to utilize this method for carbonate...... recovery was evaluated by sequential injection of various diluted seawater. The experiments applied stepwise increase in flow rate to eliminate the influence of possible capillary end effect. The total oil recovery, interaction of the different ions with the rock, and the wettability changes were studied...

  15. A novel approach for the fabrication of carbon nanofibre/ceramic porous structures

    KAUST Repository

    Walter, Claudia

    2013-11-01

    This paper describes the fabrication of hybrid ceramic/carbon scaffolds in which carbon nanofibres and multi-walled carbon nanotubes fully cover the internal walls of a microporous ceramic structure that provides mechanical stability. Freeze casting is used to fabricate a porous, lamellar ceramic (Al2O3) structure with aligned pores whose width can be controlled between 10 and 90μm. Subsequently, a two step chemical vapour deposition process that uses iron as a catalyst is used to grow the carbon nanostructures inside the scaffold. This catalyst remains in the scaffold after the growth process. The formation of the alumina scaffold and the influence of its structure on the growth of nanofibres and tubes are investigated. A set of growth conditions is determined to produce a dense covering of the internal walls of the porous ceramic with the carbon nanostructures. The limiting pore size for this process is located around 25μm. © 2013 Elsevier Ltd.

  16. Carbon diffusion in bulk hcp zirconium: A multi-scale approach

    Science.gov (United States)

    Xu, Y.; Roques, J.; Domain, C.; Simoni, E.

    2016-05-01

    In the framework of the geological repository of the used fuel claddings of pressurized water reactor, carbon behavior in bulk zirconium is studied by periodic Density Functional Theory calculations. The C interstitial sites were investigated and it was found that there are two possible carbon interstitial sites: a distorted basal tetragonal site and an octahedral site. There are four types of possible atomic jumps between them. After calculating the migration energies, the attempt frequencies and the jump probabilities for each possible migration path, kinetic Monte Carlo (KMC) simulations were performed to simulate carbon diffusion at the macroscopic scale. The results show that carbon diffusion in pure Zr bulk is extremely limited at the storage temperature (50 °C). Since there are defects in Zr bulk, in a second step, the effect of atomic vacancy was studied and it was proved that vacancies cannot increase carbon diffusion.

  17. Carbon footprint evaluation at industrial park level: A hybrid life cycle assessment approach

    International Nuclear Information System (INIS)

    Industrial parks have become the effective strategies for government to promote sustainable economic development due to the following advantages: shared infrastructure and concentrated industrial activities within planned areas. However, due to intensive energy consumption and dependence on fossil fuels, industrial parks have become the main areas for greenhouse gas emissions. Therefore, it is critical to quantify their carbon footprints so that appropriate emission reduction policies can be raised. The objective of this paper is to seek an appropriate method on evaluating the carbon footprint of one industrial park. The tiered hybrid LCA method was selected due to its advantages over other methods. Shenyang Economic and Technological Development Zone (SETDZ), a typical comprehensive industrial park in China, was chosen as a case study park. The results show that the total life cycle carbon footprint of SETDZ was 15.29 Mt, including 6.81 Mt onsite (direct) carbon footprint, 8.47 Mt upstream carbon footprint, and only 3201 t downstream carbon footprint. Analysis from industrial sector perspectives shows that chemical industry and manufacture of general purpose machinery and special purposes machinery sector were the two largest sectors for life cycle carbon footprint. Such a sector analysis may be useful for investigation of appropriate emission reduction policies. - Highlights: ► A hybrid LCA model was employed to calculate industrial park carbon footprint. ► A case study on SETDZ is done. ► Life cycle carbon footprint of SETDZ is 15.29 Mt. ► Upstream and onsite carbon footprints account for 55.40% and 44.57%, respectively. ► Chemical industry and machinery manufacturing sectors are the two largest sectors

  18. Novel in situ multiharmonic EQCM-D approach to characterize complex carbon pore architectures for capacitive deionization of brackish water.

    Science.gov (United States)

    Shpigel, Netanel; Levi, Mikhael D; Sigalov, Sergey; Aurbach, Doron; Daikhin, Leonid; Presser, Volker

    2016-03-23

    Multiharmonic analysis by electrochemical quartz-crystal microbalance with dissipation monitoring (EQCM-D) is introduced as an excellent tool for quantitative studying electrosorption of ions from aqueous solution in mesoporous (BP-880) or mixed micro-mesoporous (BP-2000) carbon electrodes. Finding the optimal conditions for gravimetric analysis of the ionic content in the charged carbon electrodes, we propose a novel approach to modeling the charge-dependent gravimetric characteristics by incorporation of Gouy-Chapman-Stern electric double layer model for ions electrosorption into meso- and micro-mesoporous carbon electrodes. All three parameters of the gravimetric equation evaluated by fitting it to the experimental mass changes curves were validated using supplementary nitrogen gas sorption analysis and complementing atomic force microscopy. Important overlap between gravimetric EQCM-D analysis of the ionic content of porous carbon electrodes and the classical capacitive deionization models has been established. The necessity and usefulness of non-gravimetric EQCM-D characterizations of complex carbon architectures, providing insight into their unique viscoelastic behavior and porous structure changes, have been discussed in detail. PMID:26902741

  19. Novel in situ multiharmonic EQCM-D approach to characterize complex carbon pore architectures for capacitive deionization of brackish water

    International Nuclear Information System (INIS)

    Multiharmonic analysis by electrochemical quartz-crystal microbalance with dissipation monitoring (EQCM-D) is introduced as an excellent tool for quantitative studying electrosorption of ions from aqueous solution in mesoporous (BP-880) or mixed micro-mesoporous (BP-2000) carbon electrodes. Finding the optimal conditions for gravimetric analysis of the ionic content in the charged carbon electrodes, we propose a novel approach to modeling the charge-dependent gravimetric characteristics by incorporation of Gouy-Chapman-Stern electric double layer model for ions electrosorption into meso- and micro-mesoporous carbon electrodes. All three parameters of the gravimetric equation evaluated by fitting it to the experimental mass changes curves were validated using supplementary nitrogen gas sorption analysis and complementing atomic force microscopy. Important overlap between gravimetric EQCM-D analysis of the ionic content of porous carbon electrodes and the classical capacitive deionization models has been established. The necessity and usefulness of non-gravimetric EQCM-D characterizations of complex carbon architectures, providing insight into their unique viscoelastic behavior and porous structure changes, have been discussed in detail. (paper)

  20. GIS based approach for atmospheric carbon absorption strategies through forests development in Indian situations

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, Surendra Kumar [CCS Univ., Meerut (India). SCRIET

    2013-07-01

    Geographical information system (GIS) play important role in forest management. An effective strategy for enhancement of atmospheric carbon absorption productivity is through forests development in degraded forest areas and waste lands. Forestry sector has significant emissions removal capability which can further be enhanced by operationalizing major afforestation and reforestation initiatives like National Mission for a Green India besides continued strengthening of the present protection regime of forests. Secondary data was collected and analyzed. Different types of waste lands require different strategies for their development into forest areas; but few waste lands like rocky regions, glacier regions etc. cannot be developed into forest areas. Atmospheric carbon management is major problem before world community in present circumstances to control environmental pollution. Various forest ecosystems play significant role in carbon absorption. The diffusional net absorption rate of anthropogenic carbon to the biosphere is some unknown function of the atmospheric partial pressure of carbon dioxide. Estimations reveal that the average carbon absorption of the forests was around 1,240 grams (1.240 Kg) of carbon per square meter of canopy area. To stabilize atmospheric CO{sub 2}, role of forestry depends on harvesting and disturbance rates, expectations of future forest productivity, and the ability to deploy technology and forest practices to increase the retention of sequestered CO{sub 2}. There is a considerable self-damping effect that will moderate the future increase of the atmospheric carbon dioxide concentration. Capacity of the ocean to absorb carbon dioxide is limited; but atmospheric carbon absorption potentiality of India forests can be increased tremendously through reforestation, afforestation and development of degraded forest areas and waste lands. About 60 % of Indian waste lands can be developed to increase forest cover with reasonable efforts. When

  1. Isotopic Approach to Soil Carbonate Dynamics and Implications for Paleoclimatic Interpretations

    Science.gov (United States)

    Pendall, E.G.; Harden, J.W.; Trumbore, S.E.; Chadwick, O.A.

    1994-01-01

    The radiocarbon content and stable isotope composition of soil carbonate are best described by a dynamic system in which isotopic reequilibration occurs as a result of recurrent dissolution and reprecipitation. Depth of water penetration into the soil profile, as well as soil age, determines the degree of carbonate isotope reequilibration. We measured ??13C, ??18O and radiocarbon content of gravel rinds and fine (soils of 3 .different ages (1000, 3800, and 6300 14 C yr B.P.) to assess the degree to which they record and preserve a climatic signal. In soils developing in deposits independently dated at 3800 and 6300 radiocarbon yr B.P., carbonate radiocarbon content above 40 cm depth suggests continual dissolution and reprecipitation, presumably due to frequent wetting events. Between 40 and 90 cm depth, fine carbonate is dissolved and precipitated as rinds that are not redissolved subsequently. Below 90 cm depth in these soils, radiocarbon content indicates that inherited, fine carbonate undergoes little dissolution and reprecipitation. In the 3800- and 6300-yr-old soils, ??13C in rind and fine carbonate follows a decreasing trend with depth, apparently in equilibrium with modern soil gas, as predicted by a diffusive model for soil CO2. ??18O also decreases with depth due to greater evaporative enrichment above 50 cm depth. In contrast, carbonate isotopes in a 1000-yr-old deposit do not reflect modern conditions even in surficial horizons; this soil has not undergone significant pedogenesis. There appears to be a lag of at least 1000 but less than 3800 yr before carbonate inherited with parent material is modified by ambient climatic conditions. Although small amounts of carbonate are inherited with the parent material, the rate of pedogenic carbonate accumulation indicates that Ca is derived primarily from eolian and rainfall sources. A model describing carbonate input and radiocarbon decay suggests that fine carbonate below 90 cm is mostly detrital (inherited

  2. GIS based approach for atmospheric carbon absorption strategies through forests development in Indian situations

    International Nuclear Information System (INIS)

    Geographical information system (GIS) play important role in forest management. An effective strategy for enhancement of atmospheric carbon absorption productivity is through forests development in degraded forest areas and waste lands. Forestry sector has significant emissions removal capability which can further be enhanced by operationalizing major afforestation and reforestation initiatives like National Mission for a Green India besides continued strengthening of the present protection regime of forests. Secondary data was collected and analyzed. Different types of waste lands require different strategies for their development into forest areas; but few waste lands like rocky regions, glacier regions etc. cannot be developed into forest areas. Atmospheric carbon management is major problem before world community in present circumstances to control environmental pollution. Various forest ecosystems play significant role in carbon absorption. The diffusional net absorption rate of anthropogenic carbon to the biosphere is some unknown function of the atmospheric partial pressure of carbon dioxide. Estimations reveal that the average carbon absorption of the forests was around 1,240 grams (1.240 Kg) of carbon per square meter of canopy area. To stabilize atmospheric CO2, role of forestry depends on harvesting and disturbance rates, expectations of future forest productivity, and the ability to deploy technology and forest practices to increase the retention of sequestered CO2. There is a considerable self-damping effect that will moderate the future increase of the atmospheric carbon dioxide concentration. Capacity of the ocean to absorb carbon dioxide is limited; but atmospheric carbon absorption potentiality of India forests can be increased tremendously through reforestation, afforestation and development of degraded forest areas and waste lands. About 60 % of Indian waste lands can be developed to increase forest cover with reasonable efforts. When National

  3. Quantification of soil organic carbon sequestration potential in cropland:A model approach

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Agroecosystems have a critical role in the terrestrial carbon cycling process.Soil organic carbon(SOC) in cropland is of great importance for mitigating atmospheric carbon dioxide increases and for global food security.With an understanding of soil carbon saturation,we analyzed the datasets from 95 global long-term agricultural experiments distributed across a vast area spanning wide ranges of temperate,subtropical and tropical climates.We then developed a statistical model for estimating SOC sequestration potential in cropland.The model is driven by air temperature,precipitation,soil clay content and pH,and explains 58% of the variation in the observed soil carbon saturation(n=76).Model validation using independent data observed in China yielded a correlation coefficient R2 of 0.74(n=19,P<0.001).Model sensitivity analysis suggested that soils with high clay content and low pH in the cold,humid regions possess a larger carbon sequestration potential than other soils.As a case study,we estimated the SOC sequestration potential by applying the model in Henan Province.Model estimations suggested that carbon(C) density at the saturation state would reach an average of 32 t C ha-1 in the top 0-20 cm soil depth.Using SOC density in the 1990s as a reference,cropland soils in Henan Province are expected to sequester an additional 100 Tg C in the future.

  4. Approach and practices of district energy planning to achieve low carbon outcomes in China

    International Nuclear Information System (INIS)

    District energy planning is an important methodology to assist in realizing a lower carbon target. However, district energy planning has not yet been incorporated into the statutory planning system in China, primarily because there are no clear standards and specifications for these plans. In this paper, we propose a general framework and low carbon estimation method for district energy planning, which is based on evaluating the low carbon energy planning practices of several new districts in China. In addition, several key points of concern in the planning process are extracted and discussed: overall infrastructure planning; co-operation between city planning and other special low carbon eco-planning; investment, financing and profitable operation; planning management mechanisms; and the management of the construction of the energy system to coincide with the project schedule. We carried out a case study of a low carbon energy plan for a new district of Beijing to evaluate our framework. Finally, we conclude that to realize the low carbon target, regional energy planning covering technologies, the market and management should be standardized as soon as possible. -- Highlights: •A general framework for district energy planning is proposed. •A case study of a low carbon energy plan for a new district is carried out. •District energy planning should be standardized as soon as possible. •The most suitable spatial scale for energy planning is at the municipal level

  5. The Utilization of the Microflora Indigenous to and Present in Oil-Bearing Formations to Selectively Plug the More Porous Zones Thereby Increasing Oil Recovery During Waterflooding

    International Nuclear Information System (INIS)

    The objective of this work is to demonstrate the use of indigenous microbes as a method of profile control in waterfloods. It is expected that as the microbial population is induced to increase, that the expanded biomass will selectively block the more permeable zones of the reservoir thereby forcing injection water to flow through the less permeable zones which will result in improved sweep efficiency. This increase in microbial population will be accomplished by injecting a nutrient solution into four injectors. Four other injectors will act as control wells. During Phase I, two wells will be cored through the zone of interest. The core will be subjected to special core analyses in order to arrive at the optimum nutrient formulation. During Phase II, nutrient injection will begin, the results monitored, and adjustments to the nutrient composition made, if necessary. Phase II also will include the drilling of three wells for post-mortem core analysis. Phase III will focus on technology transfer of the results. It should be pointed out that one expected outcome of this new technology will be a prolongation of economical waterflooding operations, i.e. economical oil recovery should continue for much longer periods in the producing wells subjected to this selective plugging technique

  6. Increasing waterflood reserves in the Wilmington Oil Field through improved reservoir characterization and reservoir management. Annual report, March 21, 1995--March 20, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, D.; Clarke, D.; Walker, S.; Phillips, C.; Nguyen, J.; Moos, D.; Tagbor, K.

    1997-08-01

    This project uses advanced reservoir characterization tools, including the pulsed acoustic cased-hole logging tool, geologic three- dimensional (3-D) modeling software, and commercially available reservoir management software to identify sands with remaining high oil saturation following waterflood. Production from the identified high oil saturation sands will be stimulated by recompleting existing production and injection wells in these sands using conventional means as well as short radius and ultra-short radius laterals. Although these reservoirs have been waterflooded over 40 years, researchers have found areas of remaining oil saturation. Areas such as the top sand in the Upper Terminal Zone Fault Block V, the western fault slivers of Upper Terminal Zone Fault Block V, the bottom sands of the Tar Zone Fault Block V, and the eastern edge of Fault Block IV in both the Upper Terminal and Lower Terminal Zones all show significant remaining oil saturation. Each area of interest was uncovered emphasizing a different type of reservoir characterization technique or practice. This was not the original strategy but was necessitated by the different levels of progress in each of the project activities.

  7. The Utilization of the Microflora Indigenous to and Present in Oil-Bearing Formations to Selectively Plug the More Porous Zones Thereby Increasing Oil Recovery During Waterflooding

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Lewis R.; Stephens, James O.; Vadie, Alex A.

    1999-11-03

    The objective of this work is to demonstrate the use of indigenous microbes as a method of profile control in waterfloods. It is expected that as the microbial population is induced to increase, that the expanded biomass will selectively block the more permeable zones of the reservoir thereby forcing injection water to flow through the less permeable zones which will result in improved sweep efficiency. This increase in microbial population will be accomplished by injecting a nutrient solution into four injectors. Four other injectors will act as control wells. During Phase I, two wells will be cored through the zone of interest. The core will be subjected to special core analyses in order to arrive at the optimum nutrient formulation. During Phase II, nutrient injection will begin, the results monitored, and adjustments to the nutrient composition made, if necessary. Phase II also will include the drilling of three wells for post-mortem core analysis. Phase III will focus on technology transfer of the results. It should be pointed out that one expected outcome of this new technology will be a prolongation of economical waterflooding operations, i.e. economical oil recovery should continue for much longer periods in the producing wells subjected to this selective plugging technique.

  8. Estimation of mechanical properties of single wall carbon nanotubes using molecular mechanics approach

    Indian Academy of Sciences (India)

    P Subba Rao; Sunil Anandatheertha; G Narayana Naik; G Gopalakrishnan

    2015-06-01

    Molecular mechanics based finite element analysis is adopted in the current work to evaluate the mechanical properties of Zigzag, Armchair and Chiral Single wall Carbon Nanotubes (SWCNT) of different diameters and chiralities. Three different types of atomic bonds, that is Carbon–Carbon covalent bond and two types of Carbon–Carbon van der Waals bonds are considered in the carbon nanotube system. The stiffness values of these bonds are calculated using the molecular potentials, namely Morse potential function and Lennard-Jones interaction potential function respectively and these stiffness’s are assigned to spring elements in the finite element model of the CNT. The geometry of CNT is built using a macro that is developed for the finite element analysis software. The finite element model of the CNT is constructed, appropriate boundary conditions are applied and the behavior of mechanical properties of CNT is studied.

  9. A combined analytical approach to studying carbon dynamics in soils and sediments.

    OpenAIRE

    Murphy, Brian

    2014-01-01

    Studying the fate of organic carbon in soils and sediments is challenging due mainly to the multiplicity of relationships that exist not only between microbial consortia but between the organic components, nutrients and break down products. Understanding what is happening to carbon in microbial systems would provide valuable information for climate change studies, agricultural planning, pollution studies and more. In this project, a method was developed using gas chromatography-mass spectr...

  10. Estimating the National Carbon Abatement Potential of City Policies: A Data-Driven Approach

    Energy Technology Data Exchange (ETDEWEB)

    O' Shaughnessy, Eric [National Renewable Energy Lab. (NREL), Golden, CO (United States); Heeter, Jenny [National Renewable Energy Lab. (NREL), Golden, CO (United States); Keyser, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Gagnon, Pieter [National Renewable Energy Lab. (NREL), Golden, CO (United States); Aznar, Alexandra [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-10-01

    Cities are increasingly taking actions such as building code enforcement, urban planning, and public transit expansion to reduce emissions of carbon dioxide in their communities and municipal operations. However, many cities lack the quantitative information needed to estimate policy impacts and prioritize city actions in terms of carbon abatement potential and cost effectiveness. This report fills this research gap by providing methodologies to assess the carbon abatement potential of a variety of city actions. The methodologies are applied to an energy use data set of 23,458 cities compiled for the U.S. Department of Energy City Energy Profile tool. The analysis develops a national estimate of the carbon abatement potential of realizable city actions in six specific policy areas encompassing the most commonly implemented city actions. The results of this analysis suggest that, in aggregate, cities could reduce nationwide carbon emissions by about 210 million metric tons of carbon dioxide (MMT CO2) per year in a 'moderate abatement scenario' by 2035 and 480 MMT CO2/year in a 'high abatement scenario' by 2035 through these common actions typically within a city's control in the six policy areas. The aggregate carbon abatement potential of these specific areas equates to a reduction of 3%-7% relative to 2013 U.S. emissions. At the city level, the results suggest the average city could reduce carbon emissions by 7% (moderate) to 19% (high) relative to current city-level emissions. In the context of U.S. climate commitments under the 21st session of the Conference of the Parties (COP21), the estimated national abatement potential of the city actions analyzed in this report equates to about 15%-35% of the remaining carbon abatement necessary to achieve the U.S. COP21 target. Additional city actions outside the scope of this report, such as community choice aggregation (city-level purchasing of renewable energy), zero energy districts, and multi

  11. Neighborhood structure influences the convergence in light capture efficiency and carbon gain: an architectural approach for cloud forest shrubs.

    Science.gov (United States)

    Guzmán Q, J Antonio; Cordero S, Roberto A

    2016-06-01

    Although plant competition is recognized as a fundamental factor that limits survival and species coexistence, its relative importance on light capture efficiency and carbon gain is not well understood. Here, we propose a new framework to explain the effects of neighborhood structures and light availability on plant attributes and their effect on plant performance in two understory shade-tolerant species (Palicourea padifolia (Roem. & Schult.) C.M. Taylor & Lorence and Psychotria elata (Swartz)) within two successional stages of a cloud forest in Costa Rica. Features of plant neighborhood physical structure and light availability, estimated by hemispherical photographs, were used to characterize the plant competition. Plant architecture, leaf attributes and gas exchange parameters extracted from the light-response curve were used as functional plant attributes, while an index of light capture efficiency (silhouette to total area ratio, averaged over all viewing angles, STAR) and carbon gain were used as indicators of plant performance. This framework is based in a partial least square Path model, which suggests that changes in plant performance in both species were affected in two ways: (i) increasing size and decreasing distance of neighbors cause changes in plant architecture (higher crown density and greater leaf dispersion), which contribute to lower STAR and subsequently lower carbon gain; and (ii) reductions in light availability caused by the neighbors also decrease plant carbon gain. The effect of neighbors on STAR and carbon gain were similar for the two forests sites, which were at different stages of succession, suggesting that the architectural changes of the two understory species reflect functional convergence in response to plant competition. Because STAR and carbon gain are variables that depend on multiple plant attributes and environmental characteristics, we suggest that changes in these features can be used as a whole-plant response approach to

  12. Neighborhood structure influences the convergence in light capture efficiency and carbon gain: an architectural approach for cloud forest shrubs.

    Science.gov (United States)

    Guzmán Q, J Antonio; Cordero S, Roberto A

    2016-06-01

    Although plant competition is recognized as a fundamental factor that limits survival and species coexistence, its relative importance on light capture efficiency and carbon gain is not well understood. Here, we propose a new framework to explain the effects of neighborhood structures and light availability on plant attributes and their effect on plant performance in two understory shade-tolerant species (Palicourea padifolia (Roem. & Schult.) C.M. Taylor & Lorence and Psychotria elata (Swartz)) within two successional stages of a cloud forest in Costa Rica. Features of plant neighborhood physical structure and light availability, estimated by hemispherical photographs, were used to characterize the plant competition. Plant architecture, leaf attributes and gas exchange parameters extracted from the light-response curve were used as functional plant attributes, while an index of light capture efficiency (silhouette to total area ratio, averaged over all viewing angles, STAR) and carbon gain were used as indicators of plant performance. This framework is based in a partial least square Path model, which suggests that changes in plant performance in both species were affected in two ways: (i) increasing size and decreasing distance of neighbors cause changes in plant architecture (higher crown density and greater leaf dispersion), which contribute to lower STAR and subsequently lower carbon gain; and (ii) reductions in light availability caused by the neighbors also decrease plant carbon gain. The effect of neighbors on STAR and carbon gain were similar for the two forests sites, which were at different stages of succession, suggesting that the architectural changes of the two understory species reflect functional convergence in response to plant competition. Because STAR and carbon gain are variables that depend on multiple plant attributes and environmental characteristics, we suggest that changes in these features can be used as a whole-plant response approach to

  13. Integrated luminous and thermal design : a cold climate approach to zero-energy carbon-neutral design education

    Energy Technology Data Exchange (ETDEWEB)

    Guzowski, M.; Abraham, L. [Minnesota Univ., Minneapolis, MN (United States). School of Architecture

    2009-07-01

    In order to address environmental concerns, the School of Architecture at the University of Minnesota recently eliminated all of the required environmental technology courses in the professional graduate architecture program and replaced them with a new studio/technology hybrid course that focuses on the integration of luminous and thermal design for zero energy and carbon-neutral architecture. The purpose was to ask students to consider how architectural design can respond to global warming and climate change and to explore the role of solar design in shaping the next generation of sustainable architecture. In particular, the new course focused on a cold-climate approach to zero-energy carbon-neutral design education. It emphasized the role of daylighting, passive cooling, natural ventilation in significantly reducing or eliminating fossil fuel consumption and greenhouse gas emissions. Thermal and bioclimatic considerations for cold climate architecture were also investigated. This paper described the methods used in the design studio and how they were integrated into the ecological and environmental content of zero-energy and carbon-neutral design processes. The design studio curriculum content, methods, outcomes, and lessons learned were discussed, as well as the design tools and assessment and analytical methods. It was concluded that the integrated ecological design model succeeded in helping students to meaningfully integrate zero-energy and carbon-neutral design thinking into their personal design and decision-making processes. 5 refs., 6 figs.

  14. A Carbon Monitoring System Approach to US Coastal Wetland Carbon Fluxes: Progress Towards a Tier II Accounting Method with Uncertainty Quantification

    Science.gov (United States)

    Windham-Myers, L.; Holmquist, J. R.; Bergamaschi, B. A.; Byrd, K. B.; Callaway, J.; Crooks, S.; Drexler, J. Z.; Feagin, R. A.; Ferner, M. C.; Gonneea, M. E.; Kroeger, K. D.; Megonigal, P.; Morris, J. T.; Schile, L. M.; Simard, M.; Sutton-Grier, A.; Takekawa, J.; Troxler, T.; Weller, D.; Woo, I.

    2015-12-01

    Despite their high rates of long-term carbon (C) sequestration when compared to upland ecosystems, coastal C accounting is only recently receiving the attention of policy makers and carbon markets. Assessing accuracy and uncertainty in net C flux estimates requires both direct and derived measurements based on both short and long term dynamics in key drivers, particularly soil accretion rates and soil organic content. We are testing the ability of remote sensing products and national scale datasets to estimate biomass and soil stocks and fluxes over a wide range of spatial and temporal scales. For example, the 2013 Wetlands Supplement to the 2006 IPCC GHG national inventory reporting guidelines requests information on development of Tier I-III reporting, which express increasing levels of detail. We report progress toward development of a Carbon Monitoring System for "blue carbon" that may be useful for IPCC reporting guidelines at Tier II levels. Our project uses a current dataset of publically available and contributed field-based measurements to validate models of changing soil C stocks, across a broad range of U.S. tidal wetland types and landuse conversions. Additionally, development of biomass algorithms for both radar and spectral datasets will be tested and used to determine the "price of precision" of different satellite products. We discuss progress in calculating Tier II estimates focusing on variation introduced by the different input datasets. These include the USFWS National Wetlands Inventory, NOAA Coastal Change Analysis Program, and combinations to calculate tidal wetland area. We also assess the use of different attributes and depths from the USDA-SSURGO database to map soil C density. Finally, we examine the relative benefit of radar, spectral and hybrid approaches to biomass mapping in tidal marshes and mangroves. While the US currently plans to report GHG emissions at a Tier I level, we argue that a Tier II analysis is possible due to national

  15. Carbon exchange in Western Siberian watershed mires and implication for the greenhouse effect. A spatial temporal modeling approach

    Energy Technology Data Exchange (ETDEWEB)

    Borren, W.

    2007-01-19

    The vast watershed mires of Western Siberia formed a significant sink of carbon during the Holocene. Because of their large area these mires might play an important role in the carbon exchange between terrestrial ecosystems and the atmosphere. However, estimation of the Holocene and future carbon balance of whole Western Siberian mires is hampered by the lack of spatially resolved models. The main objective was to assess the carbon exchange fluxes of the mires using a 3-D dynamic approach. These exchange fluxes comprise the sequestration of carbon dioxide (CO2) by peat growth, the emission of methane (CH4) by anaerobic peat decay and the emission of CO2 by aerobic peat decay. From the detailed analysis of peat cores from different sites in the southern taiga of Western Siberia, it emerged that Holocene peat growth and carbon accumulation had different trends, caused by variations in vegetation succession. These differences were strongly influenced by the position in the landscape. Therefore, the effect of climatic change on mire development varied spatially. The indirect effects of climate change through local hydrology appeared to be more important than direct influences of changes in precipitation and temperature. Mire development is closely connected to hydrological dynamics. In the thesis a 3-D dynamic modeling approach is described that makes use of groundwater modeling. In successive timesteps peat growth and decay as well as mire type distribution were calculated, depending on hydrological conditions. The model was forced with a paleo-precipitation record to include variable climatic input. The model results show the Holocene development of a watershed mire from a few small spots to a contiguous mire landscape. As hydrology is the major limiting factor, the mire development is most sensitive to precipitation and evapotranspiration. Under unchanged conditions the mire will grow further, eventually reaching its maximum peat thickness around 11400 yr A.D. Under

  16. An approach to the use of fixed carbon-volatile matter graph

    NARCIS (Netherlands)

    Radovanović, Milan; Jankes, Goran

    1986-01-01

    The use of the fixed carbon-volatile matter (FC-VM) graph for quick calculations of proximate analysis data, as well as for simple presentation of coal classification is illustrated. From the position of the VM and FC values of a coal on the graph (on an ‘as received’ basis) it is possible to determ

  17. Technical Note: Mesocosm approach to quantify dissolved inorganic carbon percolation fluxes

    DEFF Research Database (Denmark)

    Thaysen, Eike Marie; Jessen, S.; Ambus, Per;

    2014-01-01

    unplanted soil. Carbon dioxide partial pressure (pCO(2)), alkalinity, soil moisture and temperature were measured with depth and time, and DIC in the percolate was quantified using a sodium hydroxide trap. Results showed good reproducibility between two replicate mesocosms. The pCO(2) varied between 0...

  18. Assessing the Accuracy of Soil Carbon Inventories in a Forested Watershed Using Conventional and Advanced Approaches

    Science.gov (United States)

    Soils provide a number of vital Ecosystem Services (ESs) that society depends upon. Carbon held in soils contributes to a number of ESs including the production of food and fiber; water recharge, storage and purification; nutrient cycling, reducing soil erosion and climate regul...

  19. Carbon transformation and the sources of dissolved inorganic carbonate in sediments of a temperate coastal sea, the Baltic Sea: A stable isotope and modelling approach

    Science.gov (United States)

    Lipka, Marko; Liu, Bo; Wegwerth, Antje; Dellwig, Olaf; Winde, Vera; Al-Raei, Abdul M.; Böttcher, Michael E.

    2015-04-01

    Organic matter is mineralized in brackish-marine sediments by microbial activity using predominantly and sulfate as electron acceptors. Under anoxic bottom water conditions, sulfate reduction dominates. Pore water profiles reflect net biogeochemical processes, transformation rates and fluxes of dissolved species across the sediment-water interface. Element fluxes across the sediment-water interface are controlled by different boundary conditions. We present the results of a detailed biogeochemical investigation of interstitial waters from different sediments of the Baltic Sea covering the range of sedimentological and bottom water redox conditions. It was the aim to study the biogeochemical transformation processes and associated element fluxes at the sediment-water-interface and the role of organic matter or methane as potential substrates for microbial activity. Short sediment cores were collected during several research cruises with multicoring devices. Pore waters were analyzed for nutrients, major and trace element concentrations to allow a modelling of net volumetric transformation rates and diffusive element fluxes. Gross sulfate reduction rates were measured in selected cores using incubations with radiotracer. As a tracer for the source of dissolved inorganic carbonate (DIC) the carbon isotope composition was measured. A quantitative interpretation of vertical concentration profiles in the pore waters was performed using different modelling approaches. Element fluxes across the sediment-water interface show a dependence from bottom water redox conditions, sediment compositions, and sedimentation conditions. It is shown that the carbon isotope composition of DIC is a valuable and sensitive parameter in a model-based estimate of the impact of biological and physical mixing of surface sediments. Research is supported by German BMBF within the KÜNO-SECOS project and Leibniz IOW

  20. Equity and the Allocation of Miigation Burdens: A Carbon Budgets Approach

    Science.gov (United States)

    Kanitkar, T. T. I. O. S. S.

    2014-12-01

    The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5) provides global estimates of future cumulative carbon dioxide emissions of anthropogenic origin, for various representative concentration pathways (RCP). For example, for an approximately 50% probability of limiting the increase in temperature to 2 deg. C, the table shows that the limit on cumulative global carbon-dioxide emissions is 780 Gt of carbon between 2012 and 2100. We can now ask what each nation will get as a share of the globally allowed cumulative emissions. Corresponding to this share of cumulative emissions, every nation will have the flexibility to consider a range of emissions trajectories within its share. This paper calculates the "entitlements" and potential emissions (based on some reasonable growth and reduction rates) using four different methods for all the four RCPs discussed in the IPCC report - i) simply allocating the remaining carbon space (for the period from 2012 to 2100) on a per capita basis amongst the regions; ii) calculating entitlements for the period between 1850 and 2100 based on total emissions emitted in the past and allowed in the future divided among countries on a per capita basis; iii) the entitlements calculated in (ii) are weighted by per capita GDP to include a measure of 'capability' while calculating entitlements; iv) the entitlements calculated in (ii) are weighted by non-income HDI as another measure of 'capability'. The values are benchmarked against the potential emissions for the future resulting from the commitments already made by different countries and regions towards mitigation. The paper then goes on to provide an estimate for the avoided cost of carbon for India given a range of constraints on emissions that it will have to undertake as a part of such a schema of allocating the mitigation burden.

  1. Bonding titanium on multi-walled carbon nanotubes for hydrogen storage: An electrochemical approach

    Energy Technology Data Exchange (ETDEWEB)

    Brieno-Enriquez, K.M.; Ledesma-Garcia, J. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C., Parque Tecnologico Queretaro-Sanfandila, Pedro Escobedo, Qro, C.P. 76703 (Mexico); Perez-Bueno, J.J., E-mail: jperez@cideteq.mx [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C., Parque Tecnologico Queretaro-Sanfandila, Pedro Escobedo, Qro, C.P. 76703 (Mexico); Godinez, Luis A. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, S.C., Parque Tecnologico Queretaro-Sanfandila, Pedro Escobedo, Qro, C.P. 76703 (Mexico); Terrones, H. [Instituto Potosino de Investigacion Cientifica y Tecnologica, Division de Materiales Avanzados, Camino a la Presa San Jose 2055, Col. Lomas 4o Seccion C.P. 78216, San Luis Potosi (Mexico); Angeles-Chavez, C. [Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Eje Central Lazaro Cardenas 152, A.P. 14-805, 07730 Mexico D.F. (Mexico)

    2009-06-15

    This work explores the use of some procedures, involving electrochemistry, in order to bond atomic Ti on the outer surface of multi-walled carbon nanotubes (MWNTs). It is assumed that each titanium atom has the potential of host up to four hydrogen molecules and relinquish them by heated. As a way to spread and stick nanotubes on an electrode, a tested route was drying a solution with nanotubes on a glassy carbon flat electrode. The MWNTs were treated by anodic polarization in organic media. Dichloromethane was selected as the medium and titanium tetrachloride as the precursor for attaching atomic Ti onto the nanotubes. The hydrogen adsorption, estimated from voltamperometry was five times higher on Ti-MWNTs that on bare nanotubes. The use of anodic polarization during the preparation of Ti-MWNTs may represent great significance in procedure, which was manifest during the voltamperometric evaluation of samples.

  2. Ab initio study of transport properties in defected carbon nanotubes: an O(N) approach

    Energy Technology Data Exchange (ETDEWEB)

    Biel, Blanca; GarcIa-Vidal, F J; Flores, Fernando [Departamento de Fisica Teorica de la Materia Condensada, Universidad Autonoma de Madrid, E-28049 Madrid (Spain); Rubio, Angel [European Theoretical Spectroscopy Facility (ETSF), Departamento de Fisica de Materiales, Universidad PaIs Vasco, Edificio Korta, Avenida Tolosa 72, 20018 San Sebastian (Spain)], E-mail: blanca.biel@cea.fr

    2008-07-23

    A combination of ab initio simulations and linear-scaling Green's functions techniques is used to analyze the transport properties of long (up to 1 {mu}m) carbon nanotubes with realistic disorder. The energetics and the influence of single defects (monovacancies and divacancies) on the electronic and transport properties of single-walled armchair carbon nanotubes are analyzed as a function of the tube diameter by means of the local orbital first-principles Fireball code. Efficient O(N) Green's functions techniques framed within the Landauer-Buettiker formalism allow a statistical study of the nanotube conductance averaged over a large sample of defected tubes and thus extraction of the nanotube localization length. The cases of zero and room temperature are both addressed.

  3. Public Policies and the Demand for Carbonated Soft Drinks: A Censored Quantile Regression Approach

    OpenAIRE

    Gustavsen, Geir Waehler

    2005-01-01

    Heavy consumption of soda may contribute to obesity, strokes, and cardiac problems. From a health perspective, the distribution of the consumption is at least as important as the mean. Censored as well as ordinary quantile regression techniques were used to estimate the demand for sugary soda based on household data from 1989 to 1999. It was found that heavy drinkers are more price- and expenditure-responsive than are light drinkers. The study shows that increasing the taxes on carbonated sof...

  4. Assessing the environmental potential of carbon dioxide utilization: A graphical targeting approach

    OpenAIRE

    Dumont, Marie-Noëlle

    2012-01-01

    Carbon Capture and Utilization (CCU) has the potential to reduce both greenhouse gas emissions and fossil fuel use. However, the conversion of CO2 is intrinsically difficult due to its low energetic state. Thus, a positive environmental effect of a CO2-consuming reaction cannot be taken for granted. In this work, we therefore present a graphical method to identify promising reaction schemes using CO2 as a feedstock. Reactant mixtures leading to minimal life-cycle greenhouse gas (GHG) emission...

  5. The relationship between black carbon concentration and black smoke: A more general approach

    OpenAIRE

    Heal, Mathew R.; Quincey, Paul

    2012-01-01

    The black carbon (BC) component of ambient particulate matter is an important marker for combustion sources and for its impact on human health and radiative forcing. Extensive data archives exist for the black smoke metric, the historic measure of ambient particle darkness. An expression presented in earlier publications (Quincey, 2007; Quincey et al., 2011) for estimating BC concentrations from traditional black smoke measurements is shown to have limitations that can be addressed by using a...

  6. A Nanomechanical Approach on the Measurement of the Elastic Properties of Epoxy Reinforced Carbon Nanotube Nanocomposites

    OpenAIRE

    Mansour, G; D. Tzetzis; K.D. Bouzakis

    2013-01-01

    The mechanical behavior of nanocomposite materials with multiwallcarbon nanotube ( MWCNT ) reinforcements is investigated in the present paper. Epoxy nanocomposites with different weight percentages of carbon nanotubes have been characterized following tensile tests and nanoindentations. The objective of this work was to investigate the efficiency of the reinforcement provided by nanotubes and to examine the agreement between the mechanical properties of the epoxynanocomposites obtained via a...

  7. Organic carbon sources and transformations in mangrove sediments : a Rock-Eval pyrolysis approach

    OpenAIRE

    Marchand, Cyril; Lallier-Vergès, Elisabeth; Disnar, Jean-Robert; Kéravis, Didier

    2008-01-01

    International audience A Rock-Eval pyrolysis study was carried out on sedimentary cores and leaf and woody tissue of vascular plant species from the mangroves of French Guiana. These forests develop on moving mudbanks and have a lifetime limited to few decades before being eroded. Our main purpose was to complete the understanding of carbon cycling in this specific environment using a method that allows monitoring the depth evolution of sources and transformation of organic matter (OM) wit...

  8. What drives the δ18O signal in European carbonates during LGM and Termination II - multi-archive approach revised

    Science.gov (United States)

    Kwiecien, Ola; Marwan, Norbert

    2016-04-01

    Due to their natural occurrence in a wide spectrum of environmental settings (marine, lacustrine, terrestrial) carbonates constitute one of the most widely used archives of (paleo)environmental information Although the thermodynamic laws controlling isotopic fractionation are universal, each of the different environments leaves its characteristic imprint on the carbonate chemistry. Consequently, individual carbonate-based records are a combination of regional-scale and archive- or site-specific factors. Environmental heterogeneity, even within a confined geographical area, remains a challenge in teasing out the regional or local nature of the recorded climatic signal. Similarly, interpretation of new data often pays tribute to outdated assumptions. Here we compare and contrast published oxygen isotope records from different archives (lake sediments and stalagmites) from central Europe and the Black Sea region covering the time span between 26 and 8 ka BP. This exercise aims at (1) identification of the regional-scale mechanisms responsible for common trends and (2) better understanding of archive- and site-specific factors accounting for differences in the records. Additionally, this approach allows for testing 'closed vs outflowing' scenarios for the glacial Black Sea basin. It appears that changes in isotopic composition of atmospheric precipitation are a common denominator for the analyzed records. Site-specific factors include moisture source (stalagmites) and volume of the basin (lakes). Both, comparison of available geochemical records and data-based theoretical calculations suggest that since the LGM and until reconnection with Mediterranean at ca. 8 ka BP the Black Sea was an open system.

  9. The Utilization of the Microflora Indigenous to and Present in Oil-Bearing Formations to Selectively Plug the More Porous Zones Thereby Increasing Oil Recovery During Waterflooding

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Lewis R.; Byrnes, Martin J.; Stephens, James O.; Vadie, Alex A.

    1999-07-01

    This project was designed to demonstrate that a microbially enhanced oil recovery process (MEOR), developed in part under DOE Contract No. DE-AC22-90BC14665, will increase oil recovery from fluvial dominated deltaic oil reservoirs. The process involves stimulating the in-situ indigenous microbial population in the reservoir to grow in the more permeable zones, thus diverting flow to other areas of the reservoir, thereby increasing the effectiveness of the waterflood. This five and a half year project is divided into three phases, Phase I, Planning and Analysis (9 months), Phase II, Implementation (45 months), and Phase III, Technology Transfer (12 months). Phase I was completed and reported in the first annual report. This fifth annual report covers the completion of Phase II and the first six months of Phase III.

  10. Controls on the turnover of fluvial organic carbon in UK rivers - combining experimental, observational and modelling approaches.

    Science.gov (United States)

    Worrall, F.

    2015-12-01

    In-stream processing of allochthonous dissolved organic carbon (DOC) and particulate organic carbon (POC) within the UK has been shown to be significant flux pathways in the terrestrial carbon cycle with both DOC and POC evolving into carbon dioxide (CO2). A mass balance approach based upon long term monitoring records was used to consider the loss of DOM and POM across UK watersheds. The total flux of carbon to UK rivers from the terrestrial biosphere was 21.8 tonnes C/km2/yr and the net catchment loss was 70%. Including the role of fluvial organic nitrogen means that for total nitrogen species UK rivers are gaining 9.6 tonnes N/km2/yr from the terrestrial biosphere but are losing 63% of this nitrogen by the tidal limit. In a parallel study, in-situ experiments investigating rates of degradation in unfiltered surface water from a headwater, peat-dominated stream. Experiments were conducted on unfiltered samples (DOM and POM could be considered); on fresh samples (experiments were started stream-side); and over 70 hours (similar to in-stream residence time of the UK). The study found that the DOC concentration of samples in the daylight declined by 64%, compared with 6% decline for the samples kept in the dark: the POC loss in the light was 13%. The organic matter was characterised using elemental analysis (CHNOP); uv-vis spectroscopy, pyrolysis GC-MS; thermos-gravimetric analysis; bomb calorimetry and solid-state 13C nmr. Initial rate kinetics in the light were as high as 3rd order, but the study could show that no single rate law could describe the whole diurnal degradation cycle. Developing a physically-based set of rate laws for the turnover of DOM and POM over the appropriate timescales showed that the derived set of rate laws was able to explain experimental data with a 13% MAPE based on turnover in three types of organic matter (particulate, labile dissolved, refractory dissolved) although the order and rate of reactions did change between sets of

  11. Counting Carbon: A review of approaches to municipal greenhouse gas accounting in Denmark

    DEFF Research Database (Denmark)

    Damsø, Tue Noa Jacques; Kjær, Tyge; Christensen, Thomas Budde

    2016-01-01

    to methodology harmonization may be feasible, especially if driven by the development and promotion of improved methodologies and data sources for sectors in which current approaches are inadequate and by regional cooperation improving accuracy, completeness, consistency and comparability while driving down cost......The article contains an analysis of GHG accounting methodologies applied by local governments in Denmark. Eight Danish methodologies have been identified, a Danish best practice distinguished and assessed based on the criteria for good practice in GHG accounting: Relevance, comparability...... approaches and scope, identifying data availability as the key barrier for improving the specificity and dynamicity of local GHG accounts, and with it the accuracy and ability to monitor changes in emissions. In furthering an international best practice the Danish approach indicates that an adaptive approach...

  12. Transport and deposition of carbon at catchment scale: stabilization mechanisms approach

    Science.gov (United States)

    Martínez-Mena, María; Almagro, María; Díaz-Pereira, Elvira; García-Franco, Noelia; Boix-Fayos, Carolina

    2016-04-01

    Terrestrial sedimentation buries large amounts of organic carbon (OC) annually, contributing to the terrestrial carbon sink. The temporal significance of this sink will strongly depend on the attributes of the depositional environment, but also on the characteristics of the OC reaching these sites and its stability upon deposition. The fate of the redistributed OC will ultimately depend on the mechanisms of its physical and chemical protection against decomposition, its turnover rates and the conditions under which the OC is stored in sedimentary settings. This framework is more complex in Mediterranean river basins where sediments are often redistributed under a range of environmental conditions in ephemeral, intermittent and perennial fluvial courses, sometimes within the same catchment. The OC stabilization mechanisms and their relations with aggregation at different transport and sedimentary deposits is under those conditions highly uncertain. The main objective of this work was to characterize the stabilization and mineralization of OC in sediments in transit (suspended load), at a range of depositional settings (alluvial bars, reservoir sediments) and soils from the source areas in a sub-catchment (111 km2) at the headwaters of the Segura catchment in South East Spain. In order to obtain a deeper knowledge on the predominant stabilization mechanism corresponding to each erosional phase, the following organic carbon fractionation method was carried out: Four aggregate size classes were distinguished by sieving (large and small macroaggregates, free microaggregates, and free silt plus clay fraction), and the microaggregates occluded within macroaggregates (SMm) were isolated. As a further step, an oxidation of the OC occluded in silt plus clay fraction and that of the free silt plus clay fraction was performed to estimate the oxidant resistant OC pool. Measured OC in these fractions can be related to three functional pools: active (free particulate organic

  13. Summary report : direct approaches for recycling carbon dioxide into synthetic fuel.

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, Mark D. (Sandia National Laboratories, Livermore, CA); Ambrosini, Andrea; Diver, Richard B., Jr.; Siegel, Nathan Phillip; Miller, James Edward; Gelbard, Fred; Evans, Lindsey R.

    2009-01-01

    The consumption of petroleum by the transportation sector in the United States is roughly equivalent to petroleum imports into the country, which have totaled over 12 million barrels a day every year since 2004. This reliance on foreign oil is a strategic vulnerability for the economy and national security. Further, the effect of unmitigated CO{sub 2} releases on the global climate is a growing concern both here and abroad. Independence from problematic oil producers can be achieved to a great degree through the utilization of non-conventional hydrocarbon resources such as coal, oil-shale and tarsands. However, tapping into and converting these resources into liquid fuels exacerbates green house gas (GHG) emissions as they are carbon rich, but hydrogen deficient. Revolutionary thinking about energy and fuels must be adopted. We must recognize that hydrocarbon fuels are ideal energy carriers, but not primary energy sources. The energy stored in a chemical fuel is released for utilization by oxidation. In the case of hydrogen fuel the chemical product is water; in the case of a hydrocarbon fuel, water and carbon dioxide are produced. The hydrogen economy envisions a cycle in which H{sub 2}O is re-energized by splitting water into H{sub 2} and O{sub 2}, by electrolysis for example. We envision a hydrocarbon analogy in which both carbon dioxide and water are re-energized through the application of a persistent energy source (e.g. solar or nuclear). This is of course essentially what the process of photosynthesis accomplishes, albeit with a relatively low sunlight-to-hydrocarbon efficiency. The goal of this project then was the creation of a direct and efficient process for the solar or nuclear driven thermochemical conversion of CO{sub 2} to CO (and O{sub 2}), one of the basic building blocks of synthetic fuels. This process would potentially provide the basis for an alternate hydrocarbon economy that is carbon neutral, provides a pathway to energy independence, and is

  14. Comparison of atomistic and elasticity approaches for carbon diffusion near line defects in {alpha}-iron

    Energy Technology Data Exchange (ETDEWEB)

    Veiga, R.G.A., E-mail: rgaveiga@gmail.com [Universite de Lyon, INSA Lyon, Laboratoire MATEIS, UMR CNRS 5510, 25 Avenue Jean Capelle, F69621, Villeurbanne (France); Perez, M. [Universite de Lyon, INSA Lyon, Laboratoire MATEIS, UMR CNRS 5510, 25 Avenue Jean Capelle, F69621, Villeurbanne (France); Becquart, C.S. [Unite Materiaux et Transformations (UMET), Ecole Nationale Superieure de Chimie de Lille, UMR CNRS 8207, Bat. C6, F59655 Villeneuve d' Ascq Cedex (France); Laboratoire commun EDF-CNRS Etude et Modelisation des Microstructures pour le Vieillissement des Materiaux (EM2VM) (France); Clouet, E. [Service de Recherches de Metallurgie Physique, CEA/Saclay, 91191 Gif-sur-Yvette (France); Domain, C. [EDF, Recherche et Developpement, Materiaux et Mecanique des Composants, Les Renardieres, F77250 Moret sur Loing (France); Laboratoire commun EDF-CNRS Etude et Modelisation des Microstructures pour le Vieillissement des Materiaux (EM2VM) (France)

    2011-10-15

    Energy barriers for carbon migration in the neighborhood of line defects in body-centered cubic iron have been obtained by atomistic simulations. For this purpose, molecular statics with an Fe-C interatomic potential, based on the embedded atom method, has been employed. Results of these simulations have been compared to the predictions of anisotropic elasticity theory. The agreement is better for a carbon atom sitting on an octahedral site (energy minimum) than one on a tetrahedral site (saddle point). Absolute differences in the energy barriers obtained by the two methods are usually below 5 meV at distances larger than 1.5 nm from a screw dislocation and 2 nm (up to 4 nm in the glide plane) from the edge dislocation. Atomistic kinetic Monte Carlo simulations performed at T = 300 K and additional analysis based on the activation energies obtained by both methods show that they are in good qualitative agreement, despite some important quantitative discrepancies due to the large absolute errors found near the dislocation cores.

  15. Modelling Holocene carbon accumulation and methane emissions of boreal wetlands – an Earth system model approach

    Directory of Open Access Journals (Sweden)

    R. J. Schuldt

    2013-03-01

    Full Text Available Since the Last Glacial Maximum, boreal wetlands have accumulated substantial amounts of peat, estimated at 180–621 Pg of carbon. Wetlands have significantly affected the atmospheric greenhouse gas composition in the past and will play a significant role in future changes of atmospheric CO2 and CH4 concentrations. In order to investigate those changes with an Earth system model, biogeochemical processes in boreal wetlands need to be accounted for. Thus, a model of peat accumulation and decay was developed and included in the land surface model JSBACH of the Max Planck Institute Earth System Model (MPI-ESM. Here we present the evaluation of model results from 6000 yr BP to the pre-industrial period. Over this period of time, 240 Pg of peat carbon accumulated in the model in the areas north of 40° N. Simulated peat accumulation rates agree well with those reported for boreal wetlands. The model simulates CH4 emissions of 49.3 Tg CH4 yr−1 for 6000 yr BP and 51.5 Tg CH4 yr−1 for pre-industrial times. This is within the range of estimates in the literature, which range from 32 to 112 Tg CH4 yr−1 for boreal wetlands. The modelled methane emission for the West Siberian Lowlands and Hudson Bay Lowlands agree well with observations. The rising trend of methane emissions over the last 6000 yr is in agreement with measurements of Antarctic and Greenland ice cores.

  16. Evaluating two experimental approaches for measuring ecosystem carbon oxidation state and oxidative ratio

    Science.gov (United States)

    Masiello, C. A.; Gallagher, M. E.; Randerson, J. T.; Deco, R. M.; Chadwick, O. A.

    2008-09-01

    Degree of oxidation of organic carbon (Cox) is a fundamental property of the carbon cycle, reflecting the synthesis and decomposition of natural organic matter. Cox is also related to ecosystem oxidative ratio (OR), the molar ratio of O2 to CO2 fluxes associated with net ecosystem exchange (NEE). Here we compare two methods for measuring Cox and OR: (1) %C, %H, %N, and %O elemental analysis, and (2) heat of combustion (ΔHc) measured by means of bomb calorimetry coupled with %C elemental analysis (hereafter referred to as calorimetry). Compared with %C, %N, %H, and %O elemental analysis, calorimetry generates Cox and OR data more rapidly and cheaply. However, calorimetric measurements yield less accurate Cox and OR data. We additionally report Cox and OR data for a pair of biomass standards and a suite of biomass samples. The OR values we measured in these samples were less variable than OR data reported in the literature (generated by simultaneous measurement of ecosystem O2 and CO2 gas mixing ratios). Our biomass OR values had a mean of 1.03 and range of 0.99-1.06. These estimates are lower than the OR value of 1.10 that is often used to partition uptake of fossil fuel CO2 between the ocean and the terrestrial biosphere.

  17. Comparison of atomistic and elasticity approaches for carbon diffusion near line defects in α-iron

    International Nuclear Information System (INIS)

    Energy barriers for carbon migration in the neighborhood of line defects in body-centered cubic iron have been obtained by atomistic simulations. For this purpose, molecular statics with an Fe-C interatomic potential, based on the embedded atom method, has been employed. Results of these simulations have been compared to the predictions of anisotropic elasticity theory. The agreement is better for a carbon atom sitting on an octahedral site (energy minimum) than one on a tetrahedral site (saddle point). Absolute differences in the energy barriers obtained by the two methods are usually below 5 meV at distances larger than 1.5 nm from a screw dislocation and 2 nm (up to 4 nm in the glide plane) from the edge dislocation. Atomistic kinetic Monte Carlo simulations performed at T = 300 K and additional analysis based on the activation energies obtained by both methods show that they are in good qualitative agreement, despite some important quantitative discrepancies due to the large absolute errors found near the dislocation cores.

  18. Above-ground tree outside forest (TOF) phytomass and carbon estimation in the semiarid region of southern Haryana: A synthesis approach of remote sensing and field data

    Indian Academy of Sciences (India)

    Kuldeep Singh; Pritam Chand

    2012-12-01

    Trees outside forest (TOF) play an important role in global carbon cycling, since they are large pools of carbon as well as potential carbon sinks and sources to the atmosphere. In view of the importance of biomass estimates in the global carbon (C) cycle, the present study demonstrates the potential of the standwise tree outside forest inventory data and finer spatial resolution of IRS-P6 LISS-IV satellite data to classify TOF, to estimate above-ground TOF phytomass and the carbon content of TOF in a semiarid region of the southern Haryana, India. The study reports that above-ground TOF phytomass varied from 1.26 tons/ha in the scattered trees in the rural/urban area to 91.5 tons/ha in the dense linear TOF along the canal. The total above-ground TOF phytomass and carbon content was calculated as 367.04 and 174.34 tons/ha, respectively in the study area. The study results conclude that the classification of TOF and estimation of phytomass and carbon content in TOF can be successfully achieved through the combined approach of Remote Sensing and GIS based spatial technique with the supplement of field data. The present approach will help to find out the potential carbon sequestration zone in the semi-arid region of southern Haryana, India.

  19. A rational design approach to nanostructured catalysts for the oxidation of carbon monoxide

    Science.gov (United States)

    Karwacki, Christopher

    The extraordinary energetic properties of subnanometer (model for the nanosciences, where molecular species are synthesized, scaled, and engineered into functional materials. Gold nanoparticles as isolated structures are not useful as real catalysts and must co-exist with supports that provide enhanced stability and activity. Support oxides such as TiO2, Fe2O 3, CeO2, SiO2, Al2O3, ZrO 2, and graphitic (active) carbons have been shown to increase the active nature of AuNP and have been the subject of several thousand publications in the past decade. Zirconia compared to titania as a support for Au NP catalysis has been studied with limited success. In fact, the majority of observations show that zirconia is one of the lowest performing metal oxide supports involving Au NP oxidation catalysis. The likely reason for these observations is a lack of understanding of the relationship between structure and surface functionality as it pertains to ambient temperature oxidation catalysis (ATOC). Furthermore, virtually all substrate and catalyst preparations in earlier work were performed at high temperatures, typically 400--900°C, thus forming progressively monomorphic structures containing larger crystals with reduced surface functionality and porosity. In this research, I established the hypothesis based on a structural model that surface functional hydroxides are important to sustained hydrolytic reactions, such as those involving Au NP for the oxidation of CO to CO 2. Theoretical calculations by Ignatchenko, Vittadini, et al. show that zirconia readily dissociates adsorbed water on the most active and stable crystal structures (111) compared to other metal oxides, such as the common anatase (101) form of titania. Also, the support must provide a source of activated oxygen as a means to oxidize intermediate carbonates with CO 2 formation. The role of the support is to provide lattice oxygen in an activated state (O2-) for oxidation of adsorbed CO the Au NP

  20. Passive seismic monitoring in two carbon sequestration sites, a data driven approach

    NARCIS (Netherlands)

    Zhang, X.; Brouwer, J.H.; Meekes, J.A.C.; Arts, R.J.

    2011-01-01

    Passive seismic imaging during CO2 injection in geological formations gains more and more interest as part of an integrated monitoring approach. For two EU CO2 storage project sites, RECOPOL - Enhanced Coal-Bed Methane pilot site in Kaniów (Poland) and CO2SINK- CO2 injection in a saline aquifer in K

  1. Technical Note: Mesocosm approach to quantify dissolved inorganic carbon percolation fluxes

    DEFF Research Database (Denmark)

    Thaysen, Eike Marie; Jessen, S.; Ambus, Per;

    2014-01-01

    unplanted soil. Carbon dioxide partial pressure (pCO(2)), alkalinity, soil moisture and temperature were measured with depth and time, and DIC in the percolate was quantified using a sodium hydroxide trap. Results showed good reproducibility between two replicate mesocosms. The pCO(2) varied between 0.......2 and 1.1 %, and the alkalinity was 0.1-0.6 meq L-1. The measured cumulative effluent DIC flux over the 78-day experimental period was 185-196 mg L-1 m(-2) and in the same range as estimates derived from pCO(2) and alkalinity in samples extracted from the side of the mesocosm column and the drainage flux...

  2. Towards large scale aligned carbon nanotube composites: an industrial safe-by-design and sustainable approach

    Science.gov (United States)

    Boulanger, P.; Belkadi, L.; Descarpentries, J.; Porterat, D.; Hibert, E.; Brouzes, A.; Mille, M.; Patel, S.; Pinault, M.; Reynaud, C.; Mayne-L'Hermite, M.; Decamps, J. M.

    2013-04-01

    We present the main results demonstrating the feasibility of high surface (> A4 format size) semi-industrial fabrication of composites embedding VACNT in organic matrices. The process of growing VACNT exhibits several advantages regarding safety issues: integrating de facto a safe collecting procedure on the substrate, avoiding additional preparation steps and simplifying handling and protection by impregnation into a matrix. The following steps of the overall process: VACNT carpet functionalization, alignment control and impregnation, can be processed on-line in a closed and safe continuous process and lead to dramatically reduced direct nanotube exposure for workers and users. This project opens the route to a continuous, roll-to-roll, safer, cost-effective and green industrial process to manufacture composites with controlled and aligned greener "black" carbon nanotubes.

  3. Thermodynamic Approach to Enhanced Dispersion and Physical Properties in a Carbon Nanotube/Polypeptide Nanocomposite

    Science.gov (United States)

    Lovell, Conrad S.; Wise, Kristopher E.; Kim, Jae-Woo; Lillehei, Peter T.; Harrison, Joycelyn S.; Park, Cheol

    2009-01-01

    A high molecular weight synthetic polypeptide has been designed which exhibits favorable interactions with single wall carbon nanotubes (SWCNTs). The enthalpic and entropic penalties of mixing between these two molecules are reduced due to the polypeptide's aromatic sidechains and helical secondary structure, respectively. These enhanced interactions result in a well dispersed SWCNT/Poly (L-Leucine-ran-L-Phenylalanine) nanocomposite with enhanced mechanical and electrical properties using only shear mixing and sonication. At 0.5 wt% loading of SWCNT filler, the nanocomposite exhibits simultaneous increases in the Young's modulus, failure strain, and toughness of 8%, 120%, and 144%, respectively. At one kHz, the same nanotube loading level also enhances the dielectric constant from 2.95 to 22.81, while increasing the conductivity by four orders of magnitude.

  4. Heisenberg behavior of some carbon-beryllium compounds: How well truncated-CI approaches work.

    Science.gov (United States)

    Calzado, Carmen J; Monari, A; Evangelisti, S

    2011-01-30

    This works tries to establish the performance of truncated CI calculations on the evaluation of magnetic coupling parameters with respect to available FCI estimates on a set of carbon-beryllium clusters. First-, second- and third-neighbor magnetic coupling constants have been evaluated and many body effective parameters as the cyclic terms. They result from the fitting of the low-lying states to the eigenvalues of an extended Heisenberg Hamiltonian, involving not only two-body isotropic terms but also cyclic terms. SDCI and DDCI calculations have been carried out and their performance compared with FCI ones. The impact of the basis set choice and size-consistency errors have been explored.

  5. Mechanical Properties of Carbon Nanofiber Reinforced Polymer Composites-Molecular Dynamics Approach

    Science.gov (United States)

    Sharma, Sumit; Chandra, Rakesh; Kumar, Pramod; Kumar, Navin

    2016-06-01

    Molecular dynamics simulation has been used to study the effect of carbon nanofiber (CNF) volume fraction ( V f) and aspect ratio ( l/d) on mechanical properties of CNF-reinforced polypropylene (PP) composites. Materials Studio 5.5 has been used as a tool for finding the modulus and damping in composites. CNF composition in PP was varied by volume from 0% to 16%. The aspect ratio of CNF was varied from l/d = 5 to l/d = 100. Results show that, with only 2% addition by volume of CNF in PP, E 11 increases 748%. Increase in E 22 is much less in comparison to the increase in E 11. With the increase in the CNF aspect ratio ( l/d) up to l/d = 60, the longitudinal loss factor ( η 11) decreases rapidly. The results of this study have been compared with those available in the literature.

  6. Hepatoprotective mechanism of lycorine against carbon tetrachloride induced toxicity in swiss albino mice - A proteomic approach

    Institute of Scientific and Technical Information of China (English)

    Soundarrajan Ilavenil; Dhanaraj Karthik; Mariadhas Valan Arasu; Mayakrishnan Vijayakumar; Srisesharam Srigopalram; Selvaraj Arokiyaraj; Sivanesan Ravikumar; Ki Choon Choi

    2015-01-01

    Objective: To investigate the differential of protein expression in CCl4 induced mice treated with lycorine. Methods: The present study was carried out to identify the differentially expressed protein in carbon tetrachloride (CCl4) induced oxidative stress mice treated with lycorine (5 mg/kg. bw) using 2D gel and MALDI-TOF. Results: We observed many kinds of differentially expressed protein in experimental liver. Among these, three are much differently expressed protein which is identified as ATP synthase, regucalcin and HSP60; these proteins are involved in the ATP synthesis, calcium regulation and rescue the integrity cellular proteins respectively. Conclusion: This investigation provided a molecular mechanism of the lycorine during CCl4 induced oxidative stress in mice liver.

  7. A coagulation-powdered activated carbon-ultrafiltration - Multiple barrier approach for removing toxins from two Australian cyanobacterial blooms

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Mike B., E-mail: mike.dixon@sawater.com.au [Australian Water Quality Centre, SA Water Corporation, GPO Box 1751, Adelaide, SA, 5001 (Australia); School of Chemical Engineering, University of Adelaide, SA 5005 (Australia); Richard, Yann [School of Chemistry, Physics and Electronics, 48 Blvd du 11 Nov 1918, BP 2077-69616, Villeurbanne Cedex (France); Ho, Lionel [Australian Water Quality Centre, SA Water Corporation, GPO Box 1751, Adelaide, SA, 5001 (Australia); School of Earth and Environmental Sciences, University of Adelaide, SA 5005 (Australia); Chow, Christopher W.K. [Australian Water Quality Centre, SA Water Corporation, GPO Box 1751, Adelaide, SA, 5001 (Australia); O' Neill, Brian K. [School of Chemical Engineering, University of Adelaide, SA 5005 (Australia); Newcombe, Gayle [Australian Water Quality Centre, SA Water Corporation, GPO Box 1751, Adelaide, SA, 5001 (Australia)

    2011-02-28

    Cyanobacteria are a major problem for the world wide water industry as they can produce metabolites toxic to humans in addition to taste and odour compounds that make drinking water aesthetically displeasing. Removal of cyanobacterial toxins from drinking water is important to avoid serious illness in consumers. This objective can be confidently achieved through the application of the multiple barrier approach to drinking water quality and safety. In this study the use of a multiple barrier approach incorporating coagulation, powdered activated carbon (PAC) and ultrafiltration (UF) was investigated for the removal of intracellular and extracellular cyanobacterial toxins from two naturally occurring blooms in South Australia. Also investigated was the impact of these treatments on the UF flux. In this multibarrier approach, coagulation was used to remove the cells and thus the intracellular toxin while PAC was used for extracellular toxin adsorption and finally the UF was used for floc, PAC and cell removal. Cyanobacterial cells were completely removed using the UF membrane alone and when used in conjunction with coagulation. Extracellular toxins were removed to varying degrees by PAC addition. UF flux deteriorated dramatically during a trial with a very high cell concentration; however, the flux was improved by coagulation and PAC addition.

  8. A coagulation-powdered activated carbon-ultrafiltration--multiple barrier approach for removing toxins from two Australian cyanobacterial blooms.

    Science.gov (United States)

    Dixon, Mike B; Richard, Yann; Ho, Lionel; Chow, Christopher W K; O'Neill, Brian K; Newcombe, Gayle

    2011-02-28

    Cyanobacteria are a major problem for the world wide water industry as they can produce metabolites toxic to humans in addition to taste and odour compounds that make drinking water aesthetically displeasing. Removal of cyanobacterial toxins from drinking water is important to avoid serious illness in consumers. This objective can be confidently achieved through the application of the multiple barrier approach to drinking water quality and safety. In this study the use of a multiple barrier approach incorporating coagulation, powdered activated carbon (PAC) and ultrafiltration (UF) was investigated for the removal of intracellular and extracellular cyanobacterial toxins from two naturally occurring blooms in South Australia. Also investigated was the impact of these treatments on the UF flux. In this multibarrier approach, coagulation was used to remove the cells and thus the intracellular toxin while PAC was used for extracellular toxin adsorption and finally the UF was used for floc, PAC and cell removal. Cyanobacterial cells were completely removed using the UF membrane alone and when used in conjunction with coagulation. Extracellular toxins were removed to varying degrees by PAC addition. UF flux deteriorated dramatically during a trial with a very high cell concentration; however, the flux was improved by coagulation and PAC addition. PMID:21227576

  9. Prediction of powdered activated carbon doses for 2-MIB removal in drinking water treatment using a simplified HSDM approach.

    Science.gov (United States)

    Yu, Jianwei; Yang, Fong-Chen; Hung, Wei-Nung; Liu, Chia-Ling; Yang, Min; Lin, Tsair-Fuh

    2016-08-01

    The addition of powdered activated carbon (PAC) is an effective measure to cope with seasonal taste and odor (T&O) problems caused by 2-methylisoborneol (2-MIB) and trans-1, 10-dimethyl-trans-9-decalol (geosmin) in drinking water. Some T&O problems are episodic in nature, and generally require rapid responses. This paper proposed a simplified approach for the application of the homogenous surface diffusion model (HSDM) to predict the appropriate PAC doses for the removal of 2-MIB. Equilibrium and kinetic experiments were performed for 2-MIB adsorption onto five PACs in three source waters. The simplified HSDM approach was compared with the experimental data, by assigning the Freundlich 1/n value in the range of 0.1-1.0 and obtaining the Freundlich equilibrium parameter K value through a 6-hr adsorption kinetic test. The model describes the kinetic adsorption data very well for all of the tested PACs in different source waters. The results were validated using the data obtained from one full scale water treatment plant, and the differences between the predicted and observed results were within 10% range. This simplified HSDM approach may be applied for the rapid determination of PAC doses for water treatment plants when faced with 2-MIB episodes in source waters. PMID:27186686

  10. Underground coal gasification with extended CO2 utilization as economic and carbon neutral approach to address energy and fertilizer supply shortages in Bangladesh

    OpenAIRE

    Natalie Christine Nakaten; Rafiqul Islam; Thomas Kempka

    2014-01-01

    The application of underground coal gasification (UCG) with proven carbon mitigation techniques may provide a carbon neutral approach to tackle electricity and fertilizer supply shortages in Bangladesh. UCG facilitates the utilization of deep-seated coal seams, not economically exploitable by conventional coal mining. The high- calorific synthesis gas produced by UCG can be used for e.g. electricity generation or as chemical raw material for hydrogen, methanol and fertilizer production....

  11. An integrative approach to energy, carbon, and redox metabolism in the cyanobacterium Synechocystis sp. PCC 6803

    Energy Technology Data Exchange (ETDEWEB)

    Overbeek, Ross; Fonstein, Veronika; Osterman, Andrei; Gerdes, Svetlana; Vassieva, Olga; Zagnitko, Olga; Rodionov, Dmitry

    2005-02-15

    covering energy, carbon, and redox metabolism in the Synechocystis sp. PCC 6803 and other cyanobacteria has been performed (Specific Aim 4). The main objectives for this year (adjusted to reflect a new, public domain, setting of the Project research team) were: Aim 1. To develop, test, and deploy a new open source system, the SEED, for integrating community-based annotation, and comparative analysis of all publicly available microbial genomes. Develop a comprehensive genomic database by integrating within SEED all publicly available complete and nearly complete genome sequences with special emphasis on genomes of cyanobacteria, phototrophic eukaryotes, and anoxygenic phototrophic bacteria--invaluable for comparative genomic studies of energy and carbon metabolism in Synechocystis sp. PCC 6803. Aim 2. To develop the SEED's biological content in the form of a collection of encoded Subsystems largely covering the conserved cellular machinery in prokaryotes (and central metabolic machinery in eukaryotes). Aim 3. To develop, utilizing core SEED technology, the CyanoSEED--a specialized WEB portal for community-based annotation, and comparative analysis of all publicly available cyanobacterial genomes. Encode the set of additional subsystems representing key metabolic transformations in cyanobacteria and other photoautotrophs. We envisioned this resource as complementary to other public access databases for comparative genomic analysis currently available to the cyanobacterial research community. Aim 4. Perform in-depth analysis of several subsystems covering energy, carbon, and redox metabolism in the Synechocystis sp. PCC 6803 and all other cyanobacteria with available genome sequences. Reveal inconsistencies and gaps in the current knowledge of these subsystems. Use functional and genome context analysis tools in CyanoSEED to predict, whenever possible, candidate genes for inferred functional roles. To disseminate freely these conjectures and predictions by publishing

  12. Carbon export in the naturally iron-fertilized Kerguelen area of the Southern Ocean based on the 234Th approach

    Science.gov (United States)

    Planchon, F.; Ballas, D.; Cavagna, A.-J.; Bowie, A. R.; Davies, D.; Trull, T.; Laurenceau-Cornec, E. C.; Van Der Merwe, P.; Dehairs, F.

    2015-06-01

    This study examined upper-ocean particulate organic carbon (POC) export using the 234Th approach as part of the second KErguelen Ocean and Plateau compared Study expedition (KEOPS2). Our aim was to characterize the spatial and the temporal variability of POC export during austral spring (October-November 2011) in the Fe-fertilized area of the Kerguelen Plateau region. POC export fluxes were estimated at high productivity sites over and downstream of the plateau and compared to a high-nutrient low-chlorophyll (HNLC) area upstream of the plateau in order to assess the impact of iron-induced productivity on the vertical export of carbon. Deficits in 234Th activities were observed at all stations in surface waters, indicating early scavenging by particles in austral spring. 234Th export was lowest at the reference station R-2 and highest in the recirculation region (E stations) where a pseudo-Lagrangian survey was conducted. In comparison 234Th export over the central plateau and north of the polar front (PF) was relatively limited throughout the survey. However, the 234Th results support that Fe fertilization increased particle export in all iron-fertilized waters. The impact was greatest in the recirculation feature (3-4 fold at 200 m depth, relative to the reference station), but more moderate over the central Kerguelen Plateau and in the northern plume of the Kerguelen bloom (~2-fold at 200 m depth). The C : Th ratio of large (>53 μm) potentially sinking particles collected via sequential filtration using in situ pumping (ISP) systems was used to convert the 234Th flux into a POC export flux. The C : Th ratios of sinking particles were highly variable (3.1 ± 0.1 to 10.5 ± 0.2 μmol dpm-1) with no clear site-related trend, despite the variety of ecosystem responses in the fertilized regions. C : Th ratios showed a decreasing trend between 100 and 200 m depth suggesting preferential carbon loss relative to 234Th possibly due to heterotrophic degradation and

  13. Exploring a novel approach to fabricate vanadium carbide encapsulated into carbon nanotube (VC@C) with large specific surface area

    Indian Academy of Sciences (India)

    Yifu Zhang; Juecheng Zhang; Meijuan Fan; Yan’an Long; Yalan Zhong; Xinghai Liu; Chi Huang

    2013-06-01

    A novel approach to the fabrication of vanadium carbide encapsulated into carbon nanotube (VC@C) core-shell structured composite by thermal treatment with the precursor V3O7.H2O@C was developed for the first time. The as-obtained VC@C were characterized by X-ray powder diffraction (XRD), Raman spectrum, energydispersive X-ray spectrometer (EDX), elemental analysis (EA), Fourier transform infrared spectroscopy (FT)–(IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET). The results showed that VC@C with core-shell structures could be successfully synthesized at 1000 °C for 2 h. The specific surface area, average pore size and measured pore volume of VC@C were 135.46 m2/g, 4.443 nm and 0.180 cm3/g, respectively indicating that the as-obtained VC@C composite could be used as a mesoporous material. Furthermore, thermal behaviour of the as-obtained VC@C composite in air was investigated by thermogravimetric/differential thermal analyser (TG/DTA). The experimental result revealed that the carbon coated on the surface of VC has high activity with O2 in air atmosphere.

  14. Interaction of some cardiovascular drugs with bovine serum albumin at physiological conditions using glassy carbon electrode: A new approach.

    Science.gov (United States)

    Afsharan, Hadi; Hasanzadeh, Mohammad; Shadjou, Nasrin; Jouyban, Abolghasem

    2016-08-01

    In this report, for the first time, the non-modified glassy carbon electrode was used for detection of cardiovascular drug interaction with bovine serum albumin (BSA). These interactions were tested at physiological conditions (T=37°C and pH=7.4 phosphate buffer solution) in different incubation times (0-4h) by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV). The applications of DPV for quantitative investigation of some cardiovascular drug interaction with BSA (as a model of serum albumin proteins) were discussed. The herein described approach is expected to promote the exploitation of electrochemically-based methods for the study of drug-serum albumin protein interaction which is necessary in biochemical and biosensing studies. This report may open a new window to application of electrochemical sensors towards interactions of cardiovascular drugs with BSA and human serum albumin (HAS) in the near future. PMID:27157732

  15. Green chemistry approach for the synthesis of ZnO-carbon dots nanocomposites with good photocatalytic properties under visible light.

    Science.gov (United States)

    Bozetine, Hakima; Wang, Qi; Barras, Alexandre; Li, Musen; Hadjersi, Toufik; Szunerits, Sabine; Boukherroub, Rabah

    2016-03-01

    We report on a simple and one-pot synthetic method to produce ZnO/carbon quantum dots (ZnO/CQDs) nanocomposites. The morphological features and chemical composition of the nanocomposites were characterized using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analyses (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optical properties of the nanocomposites were examined using UV-visible (UV-vis) spectrophotometry. The photocatalytic activity of the ZnO/CQDs was evaluated for the degradation of a model organic pollutant, rhodamine B, under visible light irradiation at room temperature. The highly efficient photodegradation capability of the nanocomposite was demonstrated by comparison with ZnO particles, prepared using identical experimental conditions. Overall, the present approach adheres to green chemistry principles and the nanocomposite holds promise for the development of remarkably efficient catalytic systems.

  16. Green chemistry approach for the synthesis of ZnO-carbon dots nanocomposites with good photocatalytic properties under visible light.

    Science.gov (United States)

    Bozetine, Hakima; Wang, Qi; Barras, Alexandre; Li, Musen; Hadjersi, Toufik; Szunerits, Sabine; Boukherroub, Rabah

    2016-03-01

    We report on a simple and one-pot synthetic method to produce ZnO/carbon quantum dots (ZnO/CQDs) nanocomposites. The morphological features and chemical composition of the nanocomposites were characterized using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analyses (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optical properties of the nanocomposites were examined using UV-visible (UV-vis) spectrophotometry. The photocatalytic activity of the ZnO/CQDs was evaluated for the degradation of a model organic pollutant, rhodamine B, under visible light irradiation at room temperature. The highly efficient photodegradation capability of the nanocomposite was demonstrated by comparison with ZnO particles, prepared using identical experimental conditions. Overall, the present approach adheres to green chemistry principles and the nanocomposite holds promise for the development of remarkably efficient catalytic systems. PMID:26674245

  17. Radioactive and conventional toxic waste compared - An integrated approach, useful for an appraisal of carbon capture and storage (CCS)

    International Nuclear Information System (INIS)

    The interplay of nuclear and conventional toxic ('special') waste is investigated, using a novel integrated system assessment: material and system characteristics, risk assessment and regulatory approaches. The goal is to create profiles of strengths and weaknesses of wastes that are similar in their risk characteristics but dealt with differently in risk management and regulation. A further objective is to draw lessons from the comparison of different discourses and procedures of waste with a similar profile with regard to decision-making processes (the reasons for the different regulation of both waste systems are not investigated here). Finally, a side glance is ventured on carbon capture and storage (CCS) in view of the keynote lecture of Session 5. (authors)

  18. Artificial neural network approach for atomic coordinate prediction of carbon nanotubes

    Science.gov (United States)

    Acı, Mehmet; Avcı, Mutlu

    2016-07-01

    In this paper, four artificial neural network (ANN) models [i.e., feed-forward neural network (FFNN), function fitting neural network (FITNET), cascade-forward neural network (CFNN) and generalized regression neural network] have been developed for atomic coordinate prediction of carbon nanotubes (CNTs). The research reported in this study has two primary objectives: (1) to develop ANN prediction models that calculate atomic coordinates of CNTs instead of using any simulation software and (2) to use results of the ANN models as an initial value of atomic coordinates for reducing number of iterations in calculation process. The dataset consisting of 10,721 data samples was created by combining the atomic coordinates of elements and chiral vectors using BIOVIA Materials Studio CASTEP (CASTEP) software. All prediction models yield very low mean squared normalized error and mean absolute error rates. Multiple correlation coefficient (R) results of FITNET, FFNN and CFNN models are close to 1. Compared with CASTEP, calculation times decrease from days to minutes. It would seem possible to predict CNTs' atomic coordinates using ANN models can be successfully used instead of mathematical calculations.

  19. A holistic approach to carbon-enhanced metal-poor stars

    CERN Document Server

    Masseron, T; Plez, B; Van Eck, S; Primas, F; Goriely, S; Jorissen, A

    2009-01-01

    Carbon-Enhanced Metal-Poor (CEMP) stars are known to be the direct witnesses of the nucleosynthesis of the first low- and intermediate-mass stars, because they have been polluted by a now-extinct AGB star. To put CEMP stars in a broad context, we collect abundances for about 180 stars of various metallicities (from solar down to [Fe/H]=-4), luminosity classes (dwarfs and giants), and abundance patterns (C-rich and poor, Ba-rich and poor, etc), from our own sample and from literature. First, we introduce a class of CEMP stars sharing the properties of CEMP-s stars and CEMP-no stars. We also show that there is a strong correlation between Ba and C in the s-only CEMP stars. This strongly points at the operation of the 13C neutron source in low-mass AGB stars. For the CEMP-rs stars (enriched with elements from both the s- and r-processes), the correlation of the N abundances with abundances of heavy elements from the 2nd and 3rd s-process peaks bears instead the signature of the 22Ne neutron source. Adding to the...

  20. A Nanomechanical Approach on the Measurement of the Elastic Properties of Epoxy Reinforced Carbon Nanotube Nanocomposites

    Directory of Open Access Journals (Sweden)

    G. Mansour

    2013-09-01

    Full Text Available The mechanical behavior of nanocomposite materials with multiwallcarbon nanotube ( MWCNT reinforcements is investigated in the present paper. Epoxy nanocomposites with different weight percentages of carbon nanotubes have been characterized following tensile tests and nanoindentations. The objective of this work was to investigate the efficiency of the reinforcement provided by nanotubes and to examine the agreement between the mechanical properties of the epoxynanocomposites obtained via a macroscale and nanoscale experimentalmethods. Higher increase in modulus was accomplished at weight fraction of nanotube reinforcement of 1 %. The modulus as measured by the tensile tests differed an average of 18% with the results obtained from the nanoindentations, however by utilizing a proper calibration method the resulting data were corrected to only a 3% difference. The modulus results obtained from the experiments were compared with the Halpin - Tsai model and with the Thostenson - Chou model accounting for the outer layer interactions of the nanotube with the hosting matrix. A relatively good agreement was found between the models and the experiments.

  1. Calculation of phonon dispersion in carbon nanotubes using a continuum-atomistic finite element approach

    Directory of Open Access Journals (Sweden)

    Michael J. Leamy

    2011-12-01

    Full Text Available Dispersion calculations are presented for cylindrical carbon nanotubes using a manifold-based continuum-atomistic finite element formulation combined with Bloch analysis. The formulated finite elements allow any (n,m chiral nanotube, or mixed tubes formed by periodically-repeating heterojunctions, to be examined quickly and accurately using only three input parameters (radius, chiral angle, and unit cell length and a trivial structured mesh, thus avoiding the tedious geometry generation and energy minimization tasks associated with ab initio and lattice dynamics-based techniques. A critical assessment of the technique is pursued to determine the validity range of the resulting dispersion calculations, and to identify any dispersion anomalies. Two small anomalies in the dispersion curves are documented, which can be easily identified and therefore rectified. They include difficulty in achieving a zero energy point for the acoustic twisting phonon, and a branch veering in nanotubes with nonzero chiral angle. The twisting mode quickly restores its correct group velocity as wavenumber increases, while the branch veering is associated with a rapid exchange of eigenvectors at the veering point, which also lessens its impact. By taking into account the two noted anomalies, accurate predictions of acoustic and low-frequency optical branches can be achieved out to the midpoint of the first Brillouin zone.

  2. Thin graphite films formation by carbon precipitation in metals: diffusion approach

    Science.gov (United States)

    Shvets, Petr V.; Obraztsov, Alexander N.

    2016-03-01

    Thin graphite films attract significant interest due to their unique physical properties and potential applications. Chemical vapor deposition in the presence of metal catalysts is one of the most promising and widely used techniques to produce these films. There are many experimental works devoted to the material synthesis; however, the results are usually obtained by the trial-and-error method without a proper understanding of the processes behind the experiment. We theoretically analyze the carbon diffusion processes inside a metal substrate during the deposition. The theory allows interconnection of the deposition parameters with the thickness of produced graphite films. Numerically solving the diffusion equations for the real systems, we obtained a good correlation between simulations and experimental data. Based on our simulations, we made some conclusions about the formation of graphite films by the precipitation process. The numerical simulations were mostly done for the popular nickel substrates, but we also made some calculations for iron, showing that it also could be used to form thin graphite films under certain conditions.

  3. Participatory approach in planning for low carbon and eco-village: A case of Felda Taib Andak

    Science.gov (United States)

    Ngah, I.; Zulkifli, A. S.

    2014-02-01

    Participatory approaches have becoming an important tool in planning of sustainable communities. Although participation is conceived as a malleable concept there are certain methods that planners can adopt to ensure a meaningful participation. This paper will provide some experiences and lessons on how participatory planning could be carried out with local people, the role of planners in the process of plan preparation, implementation and the outcome. This paper first explores some of the meanings of participation, the criteria of participation and the approaches of participation in planning for sustainable community. The second part is a description and discussion of how participatory approach in planning was applied in planning for low carbon and eco-village in Iskandar Malaysia based on a case study of planning of Felda Taib Andak scheme. The participatory approach involved a series of meetings, site visit and focus group discussions with representative of the Felda Village to come out with action plan and actual implementation. From focus group discussions a roadmap consisted of a vision and objectives and a dozen actions were formulated and adopted. In the process of implementation the main implementation & coordination committee was form in which the author (planner) is one of its members to look into fund raising & implementation strategies together with the local people. Several task forces or sub committees responsible to implement the dozen actions were also formed. The outcome was encouraging in which some of the actions such as planting of bamboo trees, reduction of pollution from oil palm factory and bicycling activities has been implemented and shown progress. The paper also highlights some of the issues and challenges in participatory planning.

  4. Participatory approach in planning for low carbon and eco-village: A case of Felda Taib Andak

    International Nuclear Information System (INIS)

    Participatory approaches have becoming an important tool in planning of sustainable communities. Although participation is conceived as a malleable concept there are certain methods that planners can adopt to ensure a meaningful participation. This paper will provide some experiences and lessons on how participatory planning could be carried out with local people, the role of planners in the process of plan preparation, implementation and the outcome. This paper first explores some of the meanings of participation, the criteria of participation and the approaches of participation in planning for sustainable community. The second part is a description and discussion of how participatory approach in planning was applied in planning for low carbon and eco-village in Iskandar Malaysia based on a case study of planning of Felda Taib Andak scheme. The participatory approach involved a series of meetings, site visit and focus group discussions with representative of the Felda Village to come out with action plan and actual implementation. From focus group discussions a roadmap consisted of a vision and objectives and a dozen actions were formulated and adopted. In the process of implementation the main implementation and coordination committee was form in which the author (planner) is one of its members to look into fund raising and implementation strategies together with the local people. Several task forces or sub committees responsible to implement the dozen actions were also formed. The outcome was encouraging in which some of the actions such as planting of bamboo trees, reduction of pollution from oil palm factory and bicycling activities has been implemented and shown progress. The paper also highlights some of the issues and challenges in participatory planning

  5. Effects of a carbon price in the U.S. on economic sectors, resource use, and emissions. An input-output approach

    International Nuclear Information System (INIS)

    Despite differences in their implementation, most carbon policies aim to have similar outcomes: effectively raising the price of carbon-intensive products relative to non-carbon-intensive products. While it is possible to predict the simple broad-scale economic impacts of raising the price of carbon-intensive products - the demand for non-carbon-intensive products will increase - understanding the economic and environmental impacts of carbon policies throughout the life cycle of both types of products is more difficult. Using the example of a carbon tax, this study proposes a methodology that integrates short-term policy-induced consumer demand changes into the input-output framework to analyze the environmental and economic repercussions of a policy. Environmental repercussions include the direct and the indirect impacts on emissions, materials flow in the economy, and the reliance on various ecosystem goods and services. The approach combines economic data with data about physical flow of fossil fuels between sectors, consumption of natural resources and emissions from each sector. It applies several input-output modeling equations sequentially and uses various levels of aggregation/disaggregation. It is illustrated with the data for the 2002 U.S. economy and physical flows. The framework provides insight into the short-term complex interactions between carbon price and its economic and environmental effects. (author)

  6. Effects of a carbon price in the U.S. on economic sectors, resource use, and emissions: An input-output approach

    International Nuclear Information System (INIS)

    Despite differences in their implementation, most carbon policies aim to have similar outcomes: effectively raising the price of carbon-intensive products relative to non-carbon-intensive products. While it is possible to predict the simple broad-scale economic impacts of raising the price of carbon-intensive products-the demand for non-carbon-intensive products will increase-understanding the economic and environmental impacts of carbon policies throughout the life cycle of both types of products is more difficult. Using the example of a carbon tax, this study proposes a methodology that integrates short-term policy-induced consumer demand changes into the input-output framework to analyze the environmental and economic repercussions of a policy. Environmental repercussions include the direct and the indirect impacts on emissions, materials flow in the economy, and the reliance on various ecosystem goods and services. The approach combines economic data with data about physical flow of fossil fuels between sectors, consumption of natural resources and emissions from each sector. It applies several input-output modeling equations sequentially and uses various levels of aggregation/disaggregation. It is illustrated with the data for the 2002 U.S. economy and physical flows. The framework provides insight into the short-term complex interactions between carbon price and its economic and environmental effects.

  7. NEXT GENERATION COMMERCIAL HEAT PUMPWATER HEATER USING CARBON DIOXIDE USING DIFFERENT IMPROVEMENT APPROACHES

    Energy Technology Data Exchange (ETDEWEB)

    Chad Bowers; Michael Petersen; Stefan Elbel; Pega Hrnjak

    2012-04-01

    Although heat pump water heaters are today widely accepted in Japan, where energy costs are high and government incentives for their use exist, acceptance of such a product in the U.S. has been slow. This trend is slowly changing with the introduction of heat pump water heaters into the residential market, but remains in the commercial sector. Barriers to heat pump water heater acceptance in the commercial market have historically been performance, reliability and first/operating costs. The use of carbon dioxide (R744) as the refrigerant in such a system can improve performance for relatively small increase in initial cost and make this technology more appealing. What makes R744 an excellent candidate for use in heat pump water heaters is not only the wide range of ambient temperatures within which it can operate, but also the excellent ability to match water to refrigerant temperatures on the high side, resulting in very high exit water temperatures of up to 82ºC, as required by sanitary codes in the U.S. (Food Code, 2005), in a single pass, temperatures that are much more difficult to reach with other refrigerants. This can be especially attractive in applications where this water is used for the purpose of sanitation. While reliability has also been of concern historically, dramatic improvements have been made over the last several years through research done in the automotive industry and commercialization of R744 technology in residential water heating mainly in Japan. This paper presents the performance results from the development of an R744 commercial heat pump water heater of approximately 35 kW and a comparison to a baseline R134a unit of the same capacity and footprint. In addition, recommendations are made for further improvements of the R744 system which could result in possible energy savings of up to 20 %.

  8. Tracing carbon flow through coral reef food webs using a compound-specific stable isotope approach

    KAUST Repository

    McMahon, Kelton

    2015-11-21

    Coral reefs support spectacularly productive and diverse communities in tropical and sub-tropical waters throughout the world’s oceans. Debate continues, however, on the degree to which reef biomass is supported by new water column production, benthic primary production, and recycled detrital carbon (C). We coupled compound-specific stable C isotope ratio (δ13C) analyses with Bayesian mixing models to quantify C flow from primary producers to coral reef fishes across multiple feeding guilds and trophic positions in the Red Sea. Analyses of reef fishes with putative diets composed primarily of zooplankton (Amblyglyphidodon indicus), benthic macroalgae (Stegastes nigricans), reef-associated detritus (Ctenochaetus striatus), and coral tissue (Chaetodon trifascialis) confirmed that δ13C values of essential amino acids from all baseline C sources were both isotopically diagnostic and accurately recorded in consumer tissues. While all four source end-members contributed to the production of coral reef fishes in our study, a single-source end-member often dominated dietary C assimilation of a given species, even for highly mobile, generalist top predators. Microbially reworked detritus was an important secondary C source for most species. Seascape configuration played an important role in structuring resource utilization patterns. For instance, Lutjanus ehrenbergii showed a significant shift from a benthic macroalgal food web on shelf reefs (71 ± 13 % of dietary C) to a phytoplankton-based food web (72 ± 11 %) on oceanic reefs. Our work provides insights into the roles that diverse C sources play in the structure and function of coral reef ecosystems and illustrates a powerful fingerprinting method to develop and test nutritional frameworks for understanding resource utilization.

  9. Substitution of fossil carbon in metallurgy process approaches for biomass introduction via gasification

    Energy Technology Data Exchange (ETDEWEB)

    Kleinhappl, M.; Roschitz, C.; Stutterecker, W. (Austrian bioenergy centre gmbH, Area gasification, Graz (Austria)); Kepplinger, W. (Leoben University of Mining and Materials, Institute for Process Technology and Industrial Environmental Protection, Leoben (Austria)); Hofbauer, H. (Vienna University of Technology, Institute of Chemical Engineering, Environmental Technology and Biosciences, Vienna (Austria))

    2007-07-01

    A look at the historic development shows, that the early production of wrought iron by the peoples Hethitic (turkey) 1500 B.C. and Chinese 600 B.C. (cast iron); 200 A.D (blast furnace) was based on charcoal. In 1709 the utilisation of fossil coke from coal has started. About 1910 the last char coal operated blast furnaces was shut down in the deepest valley in central Europe. Nowadays we have gigantic production of crude iron in Europe, and all over the world. The monitoring of CO{sub 2} as a greenhouse gas is now done in all branches of energy, transportation and production. In this work the production of iron is analysed, as well as the systems of biomass conversion into char coal, oil and product gas. The biomass technologies of pyrolysis and gasification show suitable products. The systems of blast furnace, MIDREX and COREX show connectors to consume these products. In further work the complete utilisation of biomass with high efficiency as an additionally carrier of carbon/hydrogen will be investigated. Regarding to the necessary process data it will be focused on the path of gasification and 'gas coupling'. A path of complete gasification is preferred, because of the connection to a gas injection system of blast furnace, a DR Midrex plant and the coking plant can be combined with. For evaluation an amount of 30,000 m3/h up to 100,000 m3/h of gas with a lower heating value of minimally 10 MJ/m3 is considered. The necessary quantity of needed biomass resources has been evaluated and the delivery seems to be feasible. The gas quality requirements like inerts, acids, heating value, pressure level are discussed. The role of CO{sub 2}, its shift from fossil to renewable and the precipitation with absorption technology is lightened. The results of this work are the basis of decision in next future. (orig.)

  10. An international partnership approach to clean energy technology innovation: Carbon capture and storage

    Science.gov (United States)

    Yang, Xiaoliang

    Is a global research partnership effective in developing, deploying, and diffusing clean energy technologies? Drawing on and extending innovation system studies, this doctoral dissertation elaborates an analytical model for a global technology learning system; examines the rationales, mechanisms, and effectiveness of the United States-- China Clean Energy Research Center Advanced Coal Technology Consortium (CERC-ACTC); and analyzes government's role in developing and implementing carbon capture and storage technologies in the United States (U.S.) and China. Studies have shown that successful technology innovation leads to economic prosperity and national competence, and prove that technology innovation does not happen in isolation but rather within interactive systems among stakeholders. However, the innovation process itself remains unclear, particularly with regard to interactive learning among and between major institutional actors, including technology developers, regulators, and financial organizations. This study seeks to advance scholarship on the interactive learning from the angle of global interactive learning. This dissertation research project seeks, as well, to inform policy-makers of how to strengthen international collaboration in clean energy technology development. The U.S.--China CERC-ACTC announced by Presidents Obama and Hu in 2009, provided a unique opportunity to close this scholarly gap. ACTC aimed to "advance the coal technology needed to safely, effectively, and efficiently utilize coal resources including the ability to capture, store, and utilize the emissions from coal use in both nations " through the joint research and development by U.S. and Chinese scientists and engineers. This dissertation project included one-year field research in the two countries, with in-depth interviews of key stakeholders, a survey of Consortium participants, analysis of available data, and site visits to collaborative research projects from 2013-2014. This

  11. Oxygen-18 incorporation into malic acid during nocturnal carbon dioxide fixation in crassulacean acid metabolism plants: a new approach to estimating in vivo carbonic anhydrase activity

    Energy Technology Data Exchange (ETDEWEB)

    Holtum, J.A.M.; Summons, R.; Roeske, C.A.; Comins, H.N.; O' Leary, M.H.

    1984-01-01

    Crassulacean acid metabolism (CAM) plants fix carbon dioxide at night by the carboxylation of phosphoenolpyruvate. If CO2 fixation is conducted with TC YO2, then in the absence of carbonic anhydrase, the malate formed by dark CO2 fixation should also contain high levels of carbon-13 and oxygen-18. Conversely, if carbonic anhydrase is present and highly active, oxygen exchange between CO2 and cellular H2O will occur more rapidly than carboxylation, and the ( TC) malate formed will contain little or no oxygen-18 above the natural abundance level. The presence of oxygen-18 in these molecules can be detected either by nuclear magnetic resonance or by mass spectrometry. Studies of phosphoenolpyruvate carboxylase in the presence and absence of carbonic anhydrase in vitro confirm the validity of the method. When CAM plants are studied by this method, we find that most species show incorporation of a significant amount of oxygen-18. Comparison of these results with results of isotope fractionation and gas exchange studies permits calculation of the in vivo activity of carbonic anhydrase toward HCO3 compared with that of phosphoenolpyruvate carboxylase. The ratio (carbonic anhydrase activity/phosphoenolpyruvate carboxylase activity) is species dependent and varies from a low of about 7 for Ananas comosus to values near 20 for Hoya carnosa and Bryophyllum pinnatum, 40 for Kalanchoee daigremontiana, and 100 or greater for Bryophyllum tubiflorum, Kalanchoee serrata, and Kalanchoae tomentosa. Carbonic anhydrase activity increases relative to phosphoenolpyruvate carboxylase activity at higher temperature. 37 references, 2 figures, 8 tables.

  12. Coupled cycling of Fe and organic carbon in submarine hydrothermal systems: Modelling approach

    Science.gov (United States)

    Legendre, Louis; German, Christopher R.; Sander, Sylvia G.; Niquil, Nathalie

    2014-05-01

    It has been recently proposed that hydrothermal plumes may be a significant source of dissolved Fe to the oceans. In order to assess this proposal, we investigated the fate of dissolved Fe released from hydrothermal systems to the overlying ocean using an approach that combined modelling and field values. We based our work on a consensus conceptual model developed by members of SCOR-InterRidge Working Group 135. The model was both complex enough to capture the main processes of dissolved Fe released from hydrothermal systems and chemical transformation in the hydrothermal plume, and simple enough to be parameterized with existing field data. It included the following flows: Fe, water and heat in the high temperature vent fluids, in the fluids diffusing around the vent, and in the entrained seawater in the buoyant plume; Fe precipitation in polymetallic sulphides near the vent; transport of Fe in the non-buoyant plume, and both its precipitation in particles onto the sea bottom away from the vent and dissolution into deep-sea waters. In other words, there were three Fe input flows into the buoyant hydrothermal plume (vent-fluids; entrained diffuse flow; entrained seawater) and three Fe output flows (sedimentation from the buoyant plume as polymetallic sulfides; sedimentation from the non-buoyant plume in particulate form; export to the deep ocean in dissolved or nanoparticulate form). The output flows balanced the input flows. We transformed the conceptual model into equations, and parameterized these with field data. To do so, we assumed that all hydrothermal systems, globally, can be represented by the circumstances that prevail at the EPR 9°50'N hydrothermal field, although we knew this assumption not to be accurate. We nevertheless achieved, by following this approach, two important goals, i.e. we could assemble into a coherent framework, for the first time, several discrete data sets acquired independently over decades of field work, and we could obtain model

  13. Approaches to brain stress testing: BOLD magnetic resonance imaging with computer-controlled delivery of carbon dioxide.

    Directory of Open Access Journals (Sweden)

    W Alan C Mutch

    Full Text Available BACKGROUND: An impaired vascular response in the brain regionally may indicate reduced vascular reserve and vulnerability to ischemic injury. Changing the carbon dioxide (CO(2 tension in arterial blood is commonly used as a cerebral vasoactive stimulus to assess the cerebral vascular response, changing cerebral blood flow (CBF by up to 5-11 percent/mmHg in normal adults. Here we describe two approaches to generating the CO(2 challenge using a computer-controlled gas blender to administer: i a square wave change in CO(2 and, ii a ramp stimulus, consisting of a continuously graded change in CO(2 over a range. Responses were assessed regionally by blood oxygen level dependent (BOLD magnetic resonance imaging (MRI. METHODOLOGY/PRINCIPAL FINDINGS: We studied 8 patients with known cerebrovascular disease (carotid stenosis or occlusion and 2 healthy subjects. The square wave stimulus was used to study the dynamics of the vascular response, while the ramp stimulus assessed the steady-state response to CO(2. Cerebrovascular reactivity (CVR maps were registered by color coding and overlaid on the anatomical scans generated with 3 Tesla MRI to assess the corresponding BOLD signal change/mmHg change in CO(2, voxel-by-voxel. Using a fractal temporal approach, detrended fluctuation analysis (DFA maps of the processed raw BOLD signal per voxel over the same CO(2 range were generated. Regions of BOLD signal decrease with increased CO(2 (coded blue were seen in all of these high-risk patients, indicating regions of impaired CVR. All patients also demonstrated regions of altered signal structure on DFA maps (Hurst exponents less than 0.5; coded blue indicative of anti-persistent noise. While 'blue' CVR maps remained essentially stable over the time of analysis, 'blue' DFA maps improved. CONCLUSIONS/SIGNIFICANCE: This combined dual stimulus and dual analysis approach may be complementary in identifying vulnerable brain regions and thus constitute a regional as

  14. Oxygen-18 incorporation into malic acid during nocturnal carbon dioxide fixation in crassulacean acid metabolism plants. A new approach to estimating in vivo carbonic anhydrase activity.

    Science.gov (United States)

    Holtum, J A; Summons, R; Roeske, C A; Comins, H N; O'Leary, M H

    1984-06-10

    Crassulacean acid metabolism (CAM) plants fix carbon dioxide at night by the carboxylation of phosphoenolpyruvate. If CO2 fixation is conducted with 13C18O2 , then in the absence of carbonic anhydrase, the malate formed by dark CO2 fixation should also contain high levels of carbon-13 and oxygen-18. Conversely, if carbonic anhydrase is present and highly active, oxygen exchange between CO2 and cellular H2O will occur more rapidly than carboxylation, and the [13C] malate formed will contain little or no oxygen-18 above the natural abundance level. The presence of oxygen-18 in these molecules can be detected either by nuclear magnetic resonance (using the oxygen-18 effect on the carbon-13 chemical shift of the carboxyl carbon) or by mass spectrometry (comparing the ions at three and five units above the molecular weight with that one unit above). Studies of phosphoenolpyruvate carboxylase in the presence and absence of carbonic anhydrase in vitro confirm the validity of the method. When CAM plants are studied by this method, we find that most species show incorporation of a significant amount of oxygen-18. Comparison of these results with results of isotope fractionation and gas exchange studies permits calculation of the in vivo activity of carbonic anhydrase toward HCO-3 compared with that of phosphoenolpyruvate carboxylase. The ratio (carbonic anhydrase activity/phosphoenolpyruvate carboxylase activity) is species dependent and varies from a low of about 7 for Ananas comosus to values near 20 for Hoya carnosa and Bryophyllum pinnatum , 40 for Kalancho ë daigremontiana , and 100 or greater for Bryophyllum tubiflorum , Kalancho ë serrata, and Kalancho ë tomentosa. Carbonic anhydrase activity increases relative to phosphoenolpyruvate carboxylase activity at higher temperature. PMID:6427227

  15. A multi-scale approach to monitor urban carbon-dioxide emissions in the atmosphere over Vancouver, Canada

    Science.gov (United States)

    Christen, A.; Crawford, B.; Ketler, R.; Lee, J. K.; McKendry, I. G.; Nesic, Z.; Caitlin, S.

    2015-12-01

    Measurements of long-lived greenhouse gases in the urban atmosphere are potentially useful to constrain and validate urban emission inventories, or space-borne remote-sensing products. We summarize and compare three different approaches, operating at different scales, that directly or indirectly identify, attribute and quantify emissions (and uptake) of carbon dioxide (CO2) in urban environments. All three approaches are illustrated using in-situ measurements in the atmosphere in and over Vancouver, Canada. Mobile sensing may be a promising way to quantify and map CO2 mixing ratios at fine scales across heterogenous and complex urban environments. We developed a system for monitoring CO2 mixing ratios at street level using a network of mobile CO2 sensors deployable on vehicles and bikes. A total of 5 prototype sensors were built and simultaneously used in a measurement campaign across a range of urban land use types and densities within a short time frame (3 hours). The dataset is used to aid in fine scale emission mapping in combination with simultaneous tower-based flux measurements. Overall, calculated CO2 emissions are realistic when compared against a spatially disaggregated scale emission inventory. The second approach is based on mass flux measurements of CO2 using a tower-based eddy covariance (EC) system. We present a continuous 7-year long dataset of CO2 fluxes measured by EC at the 28m tall flux tower 'Vancouver-Sunset'. We show how this dataset can be combined with turbulent source area models to quantify and partition different emission processes at the neighborhood-scale. The long-term EC measurements are within 10% of a spatially disaggregated scale emission inventory. Thirdly, at the urban scale, we present a dataset of CO2 mixing ratios measured using a tethered balloon system in the urban boundary layer above Vancouver. Using a simple box model, net city-scale CO2 emissions can be determined using measured rate of change of CO2 mixing ratios

  16. Approach to voxel-based carbon stock quanticiation using LiDAR data in tropical rainforest, Brunei

    Science.gov (United States)

    Kim, Eunji; Piao, Dongfan; Lee, Jongyeol; Lee, Woo-Kyun; Yoon, Mihae; Moon, Jooyeon

    2016-04-01

    Forest is an important means to adapt climate change as the only carbon sink recognized by the international community (KFS 2009). According to the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5), Agriculture, Forestry, and Other Land Use (AFOLU) sectors including forestry contributed 24% of total anthropogenic emissions in 2010 (IPCC 2014; Tubiello et al. 2015). While all sectors excluding AFOLU have increased Greenhouse Gas (GHG) emissions, land use sectors including forestry remains similar level as before due to decreasing deforestation and increasing reforestation. In earlier researches, optical imagery has been applied for analysis (Jakubowski et al. 2013). Optical imagery collects spectral information in 2D. It is difficult to effectively quantify forest stocks, especially in dense forest (Cui et al. 2012). To detect individual trees information from remotely sensed data, Light detection and ranging (LiDAR) has been used (Hyyppäet al. 2001; Persson et al. 2002; Chen et al. 2006). Moreover, LiDAR has the ability to actively acquire vertical tree information such as tree height using geo-registered 3D points (Kwak et al. 2007). In general, however, geo-register 3D point was used with a raster format which contains only 2D information by missing all the 3D data. Therefore, this research aimed to use the volumetric pixel (referred as "voxel") approach using LiDAR data in tropical rainforest, Brunei. By comparing the parameters derived from voxel based LiDAR data and field measured data, we examined the relationships between them for the quantification of forest carbon. This study expects to be more helpful to take advantage of the strategic application of climate change adaption.

  17. Estimating annual soil carbon loss in agricultural peatland soils using a nitrogen budget approach.

    Directory of Open Access Journals (Sweden)

    Emilie R Kirk

    Full Text Available Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM oxidation and physical compaction. Rice (Oryza sativa production has been proposed as an alternative cropping system to limit SOM oxidation. Preliminary research on these soils revealed high N uptake by rice in N fertilizer omission plots, which we hypothesized was the result of SOM oxidation releasing N. Testing this hypothesis, we developed a novel N budgeting approach to assess annual soil C and N loss based on plant N uptake and fallow season N mineralization. Through field experiments examining N dynamics during growing season and winter fallow periods, a complete annual N budget was developed. Soil C loss was calculated from SOM-N mineralization using the soil C:N ratio. Surface water and crop residue were negligible in the total N uptake budget (3 - 4 % combined. Shallow groundwater contributed 24 - 33 %, likely representing subsurface SOM-N mineralization. Assuming 6 and 25 kg N ha-1 from atmospheric deposition and biological N2 fixation, respectively, our results suggest 77 - 81 % of plant N uptake (129 - 149 kg N ha-1 was supplied by SOM mineralization. Considering a range of N uptake efficiency from 50 - 70 %, estimated net C loss ranged from 1149 - 2473 kg C ha-1. These findings suggest that rice systems, as currently managed, reduce the rate of C loss from organic delta soils relative to other agricultural practices.

  18. A multi-variable box model approach to the soft tissue carbon pump

    Directory of Open Access Journals (Sweden)

    A. M. de Boer

    2010-12-01

    Full Text Available The canonical question of which physical, chemical or biological mechanisms were responsible for oceanic uptake of atmospheric CO2 during the last glacial is yet unanswered. Insight from paleo-proxies has led to a multitude of hypotheses but none so far have been convincingly supported in three dimensional numerical modelling experiments. The processes that influence the CO2 uptake and export production are inter-related and too complex to solve conceptually while complex numerical models are time consuming and expensive to run which severely limits the combinations of mechanisms that can be explored. Instead, an intermediate inverse box model approach of the soft tissue pump is used here in which the whole parameter space is explored. The glacial circulation and biological production states are derived from these using proxies of glacial export production and the need to draw down CO2 into the ocean. We find that circulation patterns which explain glacial observations include reduced Antarctic Bottom Water formation and high latitude upwelling and mixing of deep water and to a lesser extent reduced equatorial upwelling. The proposed mechanism of CO2 uptake by an increase of eddies in the Southern Ocean, leading to a reduced residual circulation, is not supported. Regarding biological mechanisms, an increase in the nutrient utilization in either the equatorial regions or the northern polar latitudes can reduce atmospheric CO2 and satisfy proxies of glacial export production. Consistent with previous studies, CO2 is drawn down more easily through increased productivity in the Antarctic region than the sub-Antarctic, but that violates observations of lower export production there. The glacial states are more sensitive to changes in the circulation and less sensitive to changes in nutrient utilization rates than the interglacial states.

  19. A cheap and non-destructive approach to increase coverage/loading of hydrophilic hydroxide on hydrophobic carbon for lightweight and high-performance supercapacitors.

    Science.gov (United States)

    Zhang, Liuyang; Gong, Hao

    2015-01-01

    Carbon-based substrates offer unprecedented advantages in lightweight supercapacitors. However, it is still challenging to achieve high coverage or loading. Different from the traditional belief that a lack of defects or functional groups is the cause of poor growth on carbon-based substrates, we reckon that the major cause is the discrepancy between the hydrophilic nature of the metal oxide/hydroxide and the hydrophobic nature of carbon. To solve this incompatibility, we introduced ethanol into the precursor solution. The method to synthesize nickel copper hydroxide on carbon fiber paper employs only water and ethanol, in addition to nickel acetate and copper acetate. The results revealed good growth and tight adhesion of active materials on carbon fiber paper substrates. The specific capacitance and energy density per total weight of the active material plus substrate (carbon fiber paper, current collector) reached 770 F g(-1) and 33 Wh kg(-1) (1798 F g(-1) and 54 Wh kg(-1) per weight of the active materials), owing to the high loading of active material and the light weight of carbon fiber paper. These results signified the achievability of light, cheap and high-performance supercapacitors by an environmental-friendly approach. PMID:26643665

  20. Application of the 'Climafor' Approach to Estimate Baseline Carbon Emissions of a Forest Conservation Project in the Selva Lacandona, Chiapas, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    De Jong, B.H.J.; Hellier, A.; Castillo-Santiago, M.A.; Tipper, R. [C.P. 86100 Admin. de Correos 2, Col Atasta, Villahermosa, Tabasco (Mexico)

    2005-04-15

    We present a methodology for testing and applying a regional baseline for carbon (C) emissions from land-use change, using a spatial modelling approach (hereafter called the Climafor approach). The methodology is based on an analysis of causal factors of previous land-use change (Castillo et al. 2005). Carbon risk matrices constructed from the spatial correlation analysis between observed deforestation and driving factors (Castillo et al. 2005), are used to estimate future carbon emissions within acceptable limits for a forest conservation project. The performance of two risk matrices were tested by estimating carbon emissions between 1975 and 1996 from randomly selected sample plots of sizes varying from 1,600 to 10,000 ha and comparing the results of the observed emissions from these sample plots with the model estimations. Expected emissions from continued land-use change was estimated for the community applying the risk matrices to the current land cover. The methodology provides an objective means of constructing baseline scenarios including confidence intervals, using the sum of variances of the various data sources, such as measured carbon densities, classification errors, errors in the risk matrices, and differences between the model prediction and observed emissions of sample plots due to sample size. The procedures applied in this study also give an indication of the impact of the variance in the various data sources on the size of the confidence intervals, which allows project developers to decide what data sources are essential to improve his baseline. The modelling approach to estimate the deforestation pattern is based on readily available cartographic and census data, whereas data on carbon densities are required to assess the potential for forest conservation projects to offset carbon emissions.

  1. A facile approach for the synthesis of monolithic hierarchical porous carbons – high performance materials for amine based CO2 capture and supercapacitor electrode

    KAUST Repository

    Estevez, Luis

    2013-05-03

    An ice templating coupled with hard templating and physical activation approach is reported for the synthesis of hierarchically porous carbon monoliths with tunable porosities across all three length scales (macro- meso- and micro), with ultrahigh specific pore volumes [similar]11.4 cm3 g−1. The materials function well as amine impregnated supports for CO2 capture and as supercapacitor electrodes.

  2. Carbon exchange in Western Siberian watershed mires and implication for the greenhouse effect : A spatial temporal modeling approach

    NARCIS (Netherlands)

    Borren, W.

    2007-01-01

    The vast watershed mires of Western Siberia formed a significant sink of carbon during the Holocene. Because of their large area these mires might play an important role in the carbon exchange between terrestrial ecosystems and the atmosphere. However, estimation of the Holocene and future carbon ba

  3. A model-based assessment of the TrOCA approach for estimating anthropogenic carbon in the ocean

    Directory of Open Access Journals (Sweden)

    A. Yool

    2010-02-01

    Full Text Available The quantification of the amount of anthropogenic carbon (Cant that the ocean has taken up from the atmosphere since pre-industrial times is a challenging task because of the need to deconvolute this signal from the natural, unperturbed concentration of dissolved inorganic carbon (DIC. Nonetheless, a range of techniques have been devised that perform this separation using the information implicit in other physical, biogeochemical, and man-made ocean tracers. One such method is the TrOCA approach, which belongs to a group of back-calculation techniques, but relative to other methods employs a simple parameterization for estimating the preformed, pre-industrial concentration, the key quantity needed to determine Cant. Here we examine the theoretical foundation of the TrOCA approach and test its accuracy by deconvoluting the known distribution of Cant from an ocean general circulation model (OGCM simulation of the industrial period (1864–2004. We reveal that the TrOCA tracer reflects the air-sea exchange of both natural and anthropogenic CO2 as well as that of O2. Consequently, the determination of the anthropogenic CO2 flux component requires an accurate determination not only of the contribution of the natural (pre-industrial CO2 flux component, but also of the O2 flux component. The TrOCA method attempts to achieve this by assuming that the concentration changes invoked by these two air-sea flux components scale with temperature and alkalinity. While observations support a strong exponential scaling of the oxygen flux component with temperature, there exists no simple relationship of the natural CO2 flux component with temperature and/or alkalinity. This raises doubts whether the sum of these two components can be adequately parameterized with a single function. The analyses of the model support this conclusion, even when Cant is

  4. Temporal dynamics of soil organic carbon after land-use change in the temperate zone – carbon response functions as a model approach

    DEFF Research Database (Denmark)

    Poeplau, Christopher; Don, Axel; Vesterdal, Lars;

    2011-01-01

    Land-use change (LUC) is a major driving factor for the balance of soil organic carbon (SOC) stocks and the global carbon cycle. The temporal dynamic of SOC after LUC is especially important in temperate systems with a long reaction time. On the basis of 95 compiled studies covering 322 sites...... of 0.38±0.04 Mg ha-1 yr-1 in afforestations adding up to 38±4 Mg ha-1 labile carbon after 100 years. Carbon loss after deforestation (-32±20%) and grassland conversion to cropland (-36±5%), was rapid with a new SOC equilibrium being reached after 23 and 17 years, respectively. The change rate of SOC...

  5. Energy data visualisation requires additional approaches to continue to be relevant in a world with greater low-carbon generation.

    Directory of Open Access Journals (Sweden)

    I.A. Grant Wilson

    2016-08-01

    Full Text Available The hypothesis described in this article proposes that energy visualisation diagrams commonly used need additional changes to continue to be relevant in a world with greater low-carbon generation. The diagrams that display national energy data are influenced by the properties of the type of energy being displayed, which in most cases has historically meant fossil fuels, nuclear fuels or hydro. As many energy systems throughout the world increase their use of electricity from wind or solar based renewables, a more granular display of energy data in the time domain is required. This article also introduces the shared axes energy diagram that provides a simple and powerful way in which to compare the scale and seasonality of the demands and supplies of an energy system. This aims to complement rather than replace existing diagrams, and has an additional benefit of promoting a whole systems approach to energy systems, as differing energy vectors such as natural gas, transport fuels, and electricity can all be displayed together. This in particular, is useful to both policy makers and to industry, to build a visual foundation for a whole systems narrative, which provides a basis for discussion of the synergies and opportunities across and between different energy vectors and demands. The diagram’s ability to wrap a sense of scale around a whole energy system in a simple way is thought to explain its growing popularity.

  6. A fracture mechanics approach for estimating fatigue crack initiation in carbon and low-alloy steels in LWR coolant environments

    International Nuclear Information System (INIS)

    A fracture mechanics approach for elastic-plastic materials has been used to evaluate the effects of light water reactor (LWR) coolant environments on the fatigue lives of carbon and low-alloy steels. The fatigue life of such steel, defined as the number of cycles required to form an engineering-size crack, i.e., 3-mm deep, is considered to be composed of the growth of (a) microstructurally small cracks and (b) mechanically small cracks. The growth of the latter was characterized in terms of ΔJ and crack growth rate (da/dN) data in air and LWR environments; in water, the growth rates from long crack tests had to be decreased to match the rates from fatigue S-N data. The growth of microstructurally small cracks was expressed by a modified Hobson relationship in air and by a slip dissolution/oxidation model in water. The crack length for transition from a microstructurally small crack to a mechanically small crack was based on studies on small crack growth. The estimated fatigue S-N curves show good agreement with the experimental data for these steels in air and water environments. At low strain amplitudes, the predicted lives in water can be significantly lower than the experimental values

  7. Multiscale approach to (micro)porosity quantification in continental spring carbonate facies: Case study from the Cakmak quarry (Denizli, Turkey)

    Science.gov (United States)

    De Boever, Eva; Foubert, Anneleen; Oligschlaeger, Dirk; Claes, Steven; Soete, Jeroen; Bertier, Pieter; Özkul, Mehmet; Virgone, Aurélien; Swennen, Rudy

    2016-07-01

    Carbonate spring deposits gained renewed interest as potential contributors to subsurface reservoirs and as continental archives of environmental changes. In contrast to their fabrics, petrophysical characteristics - and especially the importance of microporosity (Turkey): the extended Pond, the dipping crystalline Proximal Slope Facies and the draping Apron and Channel Facies deposits formed by encrustation of biological substrate. Integrating mercury injection capillary pressure, bulk and diffusion Nuclear Magnetic Resonance (NMR), NMR profiling and Brunauer-Emmett-Teller (BET) measurements with microscopy and micro-computer tomography (µ-CT), shows that NMR T2 distributions systematically display a single group of micro-sized pore bodies, making up between 6 and 33% of the pore space (average NMR T2 cut-off value: 62 ms). Micropore bodies are systematically located within cloudy crystal cores of granular and dendritic crystal textures in all facies. The investigated properties therefore do not reveal differences in micropore size or shape with respect to more or less biology-associated facies. The pore network of the travertine facies is distinctive in terms of (i) the percentage of microporosity, (ii) the connectivity of micropores with meso- to macropores, and (ii) the degree of heterogeneity at micro- and macroscale. Results show that an approach involving different NMR experiments provided the most complete view on the 3-D pore network especially when microporosity and connectivity are of interest.

  8. A new approach to a superconducting joining process for carbon-doped MgB2 conductor

    Science.gov (United States)

    Patel, Dipak; Hossain, Md Shahriar Al; Maeda, Minoru; Shahabuddin, Mohammed; Yanmaz, Ekrem; Pradhan, Subrata; Tomsic, Mike; Choi, Seyong; Kim, Jung Ho

    2016-09-01

    We report a new approach to a superconducting joining process for unreacted in situ carbon (C)-doped magnesium diboride (MgB2) wires. To operate a magnetic resonance imaging (MRI) magnet in the persistent mode, the superconducting joints between two conductors are as critical as the other key components. In addition, a stable and reliable joining process enables the superconducting magnet to operate without an external power supply. However, joint results using unreacted in situ C-doped MgB2 wires, which are used for high-field operation, have been limited, and only very poor performance has been obtained. By controlling the pressure inside a joint part, in this study, we successfully obtained current carrying retention in the joint of up to 72% compared to wire without a joint. The closed-circuit resistance of our closed-loop coil was less than 1.8 × 10-13 Ω at 16.7 ± 4.7 K, as measured by the field-decay measurement method. These results indicate that MgB2 has a promising future in MRI application.

  9. Towards a Carbon-Neutral Energy Sector: Opportunities and Challenges of Coordinated Bioenergy Supply Chains-A PSE Approach

    Directory of Open Access Journals (Sweden)

    Luis Puigjaner

    2015-06-01

    Full Text Available The electricity generation sector needs to reduce its environmental impact and dependence on fossil fuel, mainly from coal. Biomass is one of the most promising future options to produce electricity, given its potential contribution to climate change mitigation. Even though biomass is an old source of energy, it is not yet a well-established commodity. The use of biomass in large centralised systems requires the establishment of delivery channels to provide the desired feedstock with the necessary attributes, at the right time and place. In terms of time to deployment and cost of the solution, co-combustion/co-gasification of biomass and coal are presented as transition and short-medium term alternatives towards a carbon-neutral energy sector. Hence, there is a need to assess an effective introduction of co-combustion/co-gasification projects in the current electricity production share. The purpose of this work is to review recent steps in Process Systems Engineering towards bringing into reality individualised and ad-hoc solutions, by building a common but adjustable design platform to tailored approaches of biomass-based supply chains. Current solutions and the latest developments are presented and future needs under study are also identified.

  10. Central composite design approach towards optimization of flamboyant pods derived steam activated carbon for its use as heterogeneous catalyst in transesterification of Hevea brasiliensis oil

    International Nuclear Information System (INIS)

    Highlights: • Activated carbon was prepared from novel precursor flamboyant pods (Delonix regia). • Activation process was optimized using central composite design approach. • Prepared activated carbon at optimized condition was used as support for KOH. • Carbon based heterogeneous catalyst was used in transesterification of HBO. • Effect of catalyst loading and alcohol ratio on biodiesel yield was studied. - Abstract: The present investigation emphasises the preparation of carbon based KOH impregnated heterogeneous catalyst from flamboyant pods (Delonix regia) for the production of biodiesel from novel feedstock Hevea brasiliensis oil (HBO). Initially, carbonized char was physically activated by superheated steam and the process was optimized to study the effects of activation time and temperature by central composite design approach (CCD) using response surface methodology (RSM). Activated carbon was impregnated with KOH at four different ratios. Biodiesel production process was carried out at constant temperature 60 °C, reaction time 1 h, and 5 g of carbon based catalyst at varying quantities of catalyst loading (0.5, 2, 3.5, 5 wt%) and methanol to oil ratio (5:1–20:1). The influence of parameters on the biodiesel yield at varied condition was studied. Maximum yield of 89.3% was obtained at methanol to oil ratio 15:1 and catalyst loading 3.5 wt% and corresponding yield at same process parameters was observed to be 88.7% implying the significant activity of catalyst in reutilization. Produced biodiesel was characterized following ASTM standards. The experimental analysis confirmed that the carbonaceous catalyst developed from flamboyant pods under optimized condition is capable of transesterifying HBO into biodiesel

  11. Technical Report: Investigation of Carbon Cycle Processes within a Managed Landscape: An Ecosystem Manipulation and Isotope Tracer Approach

    Energy Technology Data Exchange (ETDEWEB)

    Griffis, Timothy J; Baker, John M; Billmark, Kaycie

    2009-06-01

    The goal of this research is to provide a better scientific understanding of carbon cycle processes within an agricultural landscape characteristic of the Upper Midwest. This project recognizes the need to study processes at multiple spatial and temporal scales to reduce uncertainty in ecosystem and landscape-scale carbon budgets to provide a sound basis for shaping future policy related to carbon management. Specifically, this project has attempted to answer the following questions: 1. Would the use of cover crops result in a shift from carbon neutral to significant carbon gain in corn-soybean rotation ecosystems of the Upper Midwest? 2. Can stable carbon isotope analyses be used to partition ecosystem respiration into its autotrophic and heterotrophic components? 3. Can this partitioning be used to better understand the fate of crop residues to project changes in the soil carbon reservoir? 4. Are agricultural ecosystems of the Upper Midwest carbon neutral, sinks, or sources? Can the proposed measurement and modeling framework help address landscape-scale carbon budget uncertainties and help guide future carbon management policy?

  12. Age-related variation in carbon allocation at tree and stand scales in beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.) using a chronosequence approach.

    Science.gov (United States)

    Genet, H; Bréda, N; Dufrêne, E

    2010-02-01

    Two types of physiological mechanisms can contribute to growth decline with age: (i) the mechanisms leading to the reduction of carbon assimilation (input) and (ii) those leading to modification of the resource economy. Surprisingly, the processes relating to carbon allocation have been little investigated as compared to research on the processes governing carbon assimilation. The objective of this paper was thus to test the hypothesis that growth decrease related to age is accompanied by changes in carbon allocation to the benefit of storage and reproductive functions in two contrasting broad-leaved species: beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.). Age-related changes in carbon allocation were studied using a chronosequence approach. Chronosequences, each consisting of several even-aged stands ranging from 14 to 175 years old for beech and from 30 to 134 years old for sessile oak, were divided into five or six age classes. In this study, carbon allocations to growth, storage and reproduction were defined as the relative amount of carbon invested in biomass increment, carbohydrate increment and seed production, respectively. Tree-ring width and allometric relationships were used to assess biomass increment at the tree and stand scales. Below-ground biomass was assessed using a specific allometric relationship between root:shoot ratio and age, established from the literature review. Seasonal variations of carbohydrate concentrations were used to assess carbon allocation to storage. Reproduction effort was quantified for beech stands by collecting seed and cupule production. Age-related flagging of biomass productivity was assessed at the tree and stand scales, and carbohydrate quantities in trees increased with age for both species. Seed and cupule production increased with stand age in beech from 56 gC m(-)(2) year(-1) at 30 years old to 129 gC m(-2) year(-1) at 138 years old. In beech, carbon allocation to storage and

  13. Origin of graphite, and temperature of metamorphism in Precambrian Eastern Ghats Mobile Belt, Orissa, India: A carbon isotope approach

    Science.gov (United States)

    Sanyal, Prasanta; Acharya, B. C.; Bhattacharya, S. K.; Sarkar, A.; Agrawal, S.; Bera, M. K.

    2009-09-01

    The carbon isotope composition of graphite and carbon and oxygen isotope composition of associated calcite from different locations of the Eastern Ghats Mobile Belt (EGMB) of Orissa have been measured in order to understand the origin of graphite. The δ 13C values of graphite range from -2.4‰ to -26.6‰. Forty-four of sixty-one samples have δ 13C values less than -20‰. Most of these low δ 13C values graphite corresponds to schists and disseminations in khondalite and calc-silicate granulites, thus indicating graphitization of organic matter. The remaining light-carbon-graphite occurs as veins which is the result of graphitization of transported organic matter. The graphite with intermediate δ 13C value (-13‰ to -19‰) indicates carbon contributions from both organic and carbonates sources and/or mantle sources. The higher δ 13C values graphite (-2.4‰ to -8.8‰) represent mantle carbon and/or carbonate sources without significant contribution from organic carbon. The temperatures of metamorphism have been estimated using carbon isotope ratios of graphite and associated calcite of calc-silicate granulites, where typical cation exchange thermometer assemblages are lacking and significant mineral reaction textures used to calculate pressure-temperature of metamorphic events are absent. Metamorphic temperatures obtained 945 °C are close to the ultrahigh-temperature reported from the EGMB. The minimum temperature estimated using the graphite-carbonate carbon isotope ratio is 90 °C. The lower estimates of temperatures probably indicate changes in the carbon isotope ratio of calcite by decarbonation reaction or armoring of carbonaceous matter in silicates during metamorphism preventing continuous exchange with calcite.

  14. Application of reservoir characterization and advanced technology to improve recovery and economics in a lower quality shallow shelf carbonate reservoir. End of budget period report, August 3, 1994--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, A.R.; Hinterlong, G.; Watts, G.; Justice, J.; Brown, K.; Hickman, T.S.

    1997-12-01

    The Oxy West Welch project is designed to demonstrate how the use of advanced technology can improve the economics of miscible CO{sub 2} injection projects in a lower quality shallow shelf carbonate reservoir. The research and design phase primarily involves advanced reservoir characterization and accelerating the production response. The demonstration phase will implement the reservoir management plan based on an optimum miscible CO{sub 2} flood as designed in the initial phase. During Budget Period 1, work was completed on the CO{sub 2} stimulation treatments and the hydraulic fracture design. Analysis of the CO{sub 2} stimulation treatment provided a methodology for predicting results. The hydraulic fracture treatment proved up both the fracture design approach a and the use of passive seismic for mapping the fracture wing orientation. Although the 3-D seismic interpretation is still being integrated into the geologic model and interpretation of borehole seismic is still underway, the simulator has been enhanced to the point of giving good waterflood history matches. The simulator-forecasted results for an optimal designed miscible CO{sub 2} flood in the demonstration area gave sufficient economics to justify continuation of the project into Budget Period 2.

  15. An ecofriendly approach to process rice bran for high quality rice bran oil using supercritical carbon dioxide for nutraceutical applications.

    Science.gov (United States)

    Balachandran, C; Mayamol, P N; Thomas, Shiny; Sukumar, Divya; Sundaresan, A; Arumughan, C

    2008-05-01

    An integrated approach to extraction and refining of RBO using supercritical carbon dioxide (SC-CO2) in order to preserve the nutritionally important phytochemicals is reported here. Process variables such as pressure, temperature, time, solvent flow rate and packing material on extraction yield and quality of RBO were investigated using a pilot model SC-CO2 extraction system. Three isobaric (350, 425 and 500 bar), three isothermal temperatures (50, 60 and 70 degrees C), three extraction times (0.5, 1 and 1.5h), at 40/min CO2 flow rate and three packing materials (pebbles, glass beads and structured SS rings) were employed. The RBO yield with SC-CO2 extraction increased with temperature and time under isobaric conditions. At the 60 degrees C isotherm, an increase in the RBO yield was obtained with an increase in the pressure and time. The RBO yield increased significantly with structured SS rings used as packing material. The RBO extracted with SC-CO2 had negligible phosphatides, wax and prooxidant metals (Fe and Cu) and was far superior in color quality when compared with RBO extracted with hexane. At the optimum condition of extraction at 500 bar, 60 degrees C for 1.5h, with structured SS rings used as packing material, the yield of RBO was comparable with that of hexane extraction (22.5%). The phytochemical contents of the RBO under the optimum conditions were in the range of tocols, 1500-1800 ppm; sterols, 15,350-19,120 ppm and oryzanol 5800-11,110 ppm. PMID:17669647

  16. A new proposed approach for future large-scale de-carbonization coal-fired power plants

    International Nuclear Information System (INIS)

    The post-combustion CO2 capture technology provides a feasible and promising method for large-scale CO2 capture in coal-fired power plants. However, the large-scale CO2 capture in conventionally designed coal-fired power plants is confronted with various problems, such as the selection of the steam extraction point and steam parameter mismatch. To resolve these problems, an improved design idea for the future coal-fired power plant with large-scale de-carbonization is proposed. A main characteristic of the proposed design is the adoption of a back-pressure steam turbine, which extracts the suitable steam for CO2 capture and ensures the stability of the integrated system. A new let-down steam turbine generator is introduced to retrieve the surplus energy from the exhaust steam of the back-pressure steam turbine when CO2 capture is cut off. Results show that the net plant efficiency of the improved design is 2.56% points higher than that of the conventional one when CO2 capture ratio reaches 80%. Meanwhile, the net plant efficiency of the improved design maintains the same level to that of the conventional design when CO2 capture is cut off. Finally, the match between the extracted steam and the heat demand of the reboiler is significantly increased, which solves the steam parameter mismatch problem. The techno-economic analysis indicates that the proposed design is a cost-effective approach for the large-scale CO2 capture in coal-fired power plants. - Highlights: • Problems caused by CO2 capture in the power plant are deeply analyzed. • An improved design idea for coal-fired power plants with CO2 capture is proposed. • Thermodynamic, exergy and techno-economic analyses are quantitatively conducted. • Energy-saving effects are found in the proposed coal-fired power plant design idea

  17. Modeling carbon sequestration in afforestation, agroforestry and forest management projects: the CO2FIX V.2 approach

    NARCIS (Netherlands)

    Masera, O.R.; Garza-Caligaris, J.F.; Kanninen, M.; Karjalainen, T.; Liski, J.; Nabuurs, G.J.; Pussinen, A.; Jong de, B.H.J.; Mohren, G.M.J.

    2003-01-01

    The paper describes the Version 2 of the CO2FIX (CO2FIX V.2) model, a user-friendly tool for dynamically estimating the carbon sequestration potential of forest management, agroforesty and afforestation projects. CO2FIX V.2 is a multi-cohort ecosystem-level model based on carbon accounting of forest

  18. The utilization of the microflora indigenous to and present in oil-bearing formations to selectively plug the more porous zones thereby increasing oil recovery during waterflooding. Annual report for the period, January 1, 1994--December 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.; Vadie, A.

    1995-08-01

    This project is a field demonstration of the ability of insitu indigenous microorganisms in the North Blowhorn Creek Oil Field to reduce the flow of injection water in the more permeable zones thereby diverting flow to other areas of the reservoir and thus increase the efficiency of the waterflooding operation. This effect is to be accomplished by adding inorganic nutrients in the form of Potassium nitrate and orthophosphate, to the injection water. In Phase I, which has been completed, the following results were obtained. Two new wells were drilled in the field and live cores were recovered. Analyses of the cores proved that viable microorganisms were present and since no sulfate-reducing bacteria (SRB) were found, the area in which the wells were drilled, probably had not been impacted by injection water, since SRB were prevalent in fluids from most wells in the field. Laboratory waterflooding tests using live cores demonstrated that the rate of flow Of simulated production water through the core increased with time when used alone while the rate of flow decreased when nitrate and phosphate salts were added to the simulated production water. Since there is only a small amount of pressure on the influent, the simulated production water was not forced to sweep other areas of the core. The field demonstration (Phase II) involves adding nutrients to four injector wells and monitoring the surrounding producers. The exact kind and amounts of nutrients to be employed and the schedule for their injection were formulated on the basis of information obtained in the laboratory waterflooding tests conducted using the live cores from the field. Results obtained in these tests will not only be compared to historical data for the wells but also to four injectors and their corresponding producers (control) which were chosen for their similarity to the four test patterns.

  19. Improving the assessment of the State of the Carbon Cycle in North America by integrating inventory- and process- based approaches: A case study for Canada

    Science.gov (United States)

    Hayes, D. J.; Smyth, C.; Chen, G.; Kurz, W.; Stinson, G.; McGuire, A. D.

    2015-12-01

    Regional and continental carbon stock and flux estimates differ among assessments depending on the scaling approach used and the budget components considered. This is particularly manifest across the vast circum-boreal region, which has experienced substantial modification of the major driving forces of the carbon cycle in recent decades, including pronounced climate warming and associated increases in the frequency and severity of disturbances. In Canada, inventory-based estimates suggest a small carbon sink for its managed forest, but do not include unmanaged lands nor capture major driving forces such as climate change and atmospheric chemistry. On the other hand, estimates from process-based models vary widely and often do not consider critical disturbance and management impacts. Here, we demonstrate results from an updated approach that integrates inventory-based information on management and disturbances with process-level representation of ecological dynamics using a terrestrial biogeochemistry model. The integrated approach facilitates more comprehensive diagnosis of Canada's land-based carbon budget within a framework that also allows for attribution of the major driving forces and prediction under future scenarios. Using this framework, we diagnose an approximately 30 Tg C yr-1 sink in Canada over the first decade of the 21st Century, which represents a significant reduction in the strength of the CO2 sink estimated for previous decades. This decline in sink strength is attributed primarily to CO2 emissions from the substantial area disturbed by wildfire and insect outbreaks in recent years. Such changes are predicted to create positive feedbacks to the climate system that accelerate global warming. Compared to other assessments, our results suggest that CO2 uptake by the region's ecosystems may not be as strong as estimated by atmospheric inverse approaches, which are highly uncertain over the high latitudes, or by process-based models that do not

  20. The Rhume springs revisited: A multi-tracer approach to one of the largest European carbonate-gypsum karst systems

    Science.gov (United States)

    Böttcher, Michael E.; Schmiedinger, Iris; Dellwig, Olaf; Escher, Peter; Weise, Stephan M.

    2014-05-01

    Modern karst ground water systems are at the cutting edge between atmosphere, hydrosphere, and geosphere and are impacted by the biosphere and anthroposphere. The hydrogeochemical processes in karst terrains are sensitive to both climate change and anthropogenic activity, thereby affecting the quality of these ground waters. Therefore, understanding the transport processes and hydrogeochemical interactions between surface and ground waters is of fundamental importance for the prediction of future quality developments of large drinking water resources. The system of the Rhume spring, at the SW border of the Harz Mountains (Germany), one of the largest the largest European karst springs, has been investigated for hydrogeochemical and isotope variations to study the impact of river waters on the Rhume spring system. Rivers from the Harz Mountains are infiltrating Quaternary strata and emerging, after a passage through Permian (Zechstein) carbonate and sulfate rocks at the Rhume springs. By using a hydrogeochemical tracer approach it was found earlier, that an old mineralized ground water that had been modified by subterrestrial water-rock interactions is mixed with less mineralized younger karst waters before emerging in the different Rhume spring pits [1-4]. In the present communication, we present new results from a revisit of the Rhume springs and the rivers and streams in the direct and tributary recharge areas focussing on trace metal concentrations and multi-stable isotope signatures under different hydrological conditions. It was the aim of the investigation to re-analyze the proposed mixing model and provide additional evidence for a relative age estimate (H-3 dating) of the different waters emerging in the Rhume spring area. One focus was set on a high water-impact period. By the application of a multi-tracer approach (e.g., Sr, Ba, Fe, Mn, Mo, PO4, Si), and different isotope systems (S-32/S-34 in sulfate; O-16, O-17, O-18, H-1, H-2, and H-3 in water, C-12/C

  1. Enhancement of the sweep efficiency of waterflooding operations by the in-situ microbial population of petroleum reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.R.; Vadie, A.A.; Stephens, J.O.; Azadpour, A.

    1995-12-31

    Live cores were obtained from five reservoirs using special precautions to prevent contamination by exogenous microorganisms and minimize exposure to oxygen. The depths from which the cores were obtained ranged from 2,705 ft to 6,568 ft. Core plugs were cut radially from live cores, encased in heat-shrink plastic tubes, placed in core holders, and fitted with inlets and outlets. Nutrient additions stimulated the in-situ microbial population to increase, dissolve stratal material, produce gases, and release oil. Reduction in flow through the core plugs was observed in some cases, while in other cases flow was increased, probably due to the dissolution of carbonates in the formation. A field demonstration of the ability of the in-situ microbial population to increase oil recovery by blocking the more permeable zones of the reservoir is currently underway. This demonstration is being conducted in the North Blowhorn Creek Unit situated in Lamar County, Alabama. Live cores were obtained from a newly drilled well in the field and tested as described above. The field project involves four test patterns each including one injector, four to five producers, and a comparable control injector with its four to five producers. Nutrient injection in the field began November 1994.

  2. A model-based assessment of the TrOCA approach for estimating anthropogenic carbon in the ocean

    OpenAIRE

    Yool, A.; Oschlies, A.; De Nurser, A. J. G.; Gruber, N.

    2010-01-01

    The quantification of the amount of anthropogenic carbon (Cant) that the ocean has taken up from the atmosphere since pre-industrial times is a challenging task because of the need to deconvolute this signal from the natural, unperturbed concentration of dissolved inorganic carbon (DIC). Nonetheless, a range of techniques have been devised that perform this separation using the information implicit in other physical, biogeochemical, and man-made ocean tracers. One such ...

  3. A model-based assessment of the TrOCA approach for estimating anthropogenic carbon in the ocean

    OpenAIRE

    Yool, A.; Oschlies, A.; De Nurser, A. J. G.; Gruber, N.

    2010-01-01

    The quantification of the amount of anthropogenic carbon (Cant) that the ocean has taken up from the atmosphere since pre-industrial times is a challenging task because of the need to deconvolute this signal from the natural, unperturbed concentration of dissolved inorganic carbon (DIC). Nonetheless, a range of techniques have been devised that perform this separation using the information implicit in other physical, biogeochemical, and man-made ocean tracers. One such ...

  4. An Integrative Approach to Energy, Carbon, and Redox Metabolism in the Cyanobacterium Synechocystis sp. PCC 6803. Special Report

    Energy Technology Data Exchange (ETDEWEB)

    Overbeek, R.

    2003-06-30

    The main objectives for the first year were to produce a detailed metabolic reconstruction of synechocystis sp. PCC 6803 especially in interrelated areas of photosynthesis, respiration, and central carbon metabolism to support a more complete understanding and modeling of this organism. Additionally, Integrated Genomics, Inc., provided detailed bioinformatic analysis of selected functional systems related to carbon and energy generation and utilization, and of the corresponding pathways, functional roles and individual genes to support wet lab experiments by collaborators.

  5. Carbon, oxygen and their interaction with intrinsic point defects in solar silicon ribbon material: A speculative approach

    Science.gov (United States)

    Goesele, U.; Ast, D. G.

    1983-01-01

    Some background information on intrinsic point defects is provided and on carbon and oxygen in silicon in so far as it may be relevant for the efficiency of solar cells fabricated from EFG ribbon material. The co-precipitation of carbon and oxygen and especially of carbon and silicon self interstitials are discussed. A simple model for the electrical activity of carbon-self-interstitial agglomerates is presented. The self-interstitial content of these agglomerates is assumed to determine their electrical activity and that both compressive stresses (high self-interstitial content) and tensile stresses (low self-interstitial content) give rise to electrical activity of the agglomerates. The self-interstitial content of these carbon-related agglomerates may be reduced by an appropriate high temperature treatment and enhanced by a supersaturation of self-interstitials generated during formation of the p-n junction of solar cells. Oxygen present in supersaturation in carbon-rich silicon may be induced to form SiO, precipitates by self-interstitials generated during phosphorus diffusion. It is proposed that the SiO2-Si interface of the precipates gives rise to a continuum of donor stables and that these interface states are responsible for at least part of the light inhancement effects observed in oxygen containing EFG silicon after phosphorus diffusion.

  6. A Micelle Fusion-Aggregation Assembly Approach to Mesoporous Carbon Materials with Rich Active Sites for Ultrasensitive Ammonia Sensing.

    Science.gov (United States)

    Luo, Wei; Zhao, Tao; Li, Yuhui; Wei, Jing; Xu, Pengcheng; Li, Xinxin; Wang, Youwei; Zhang, Wenqing; Elzatahry, Ahmed A; Alghamdi, Abdulaziz; Deng, Yonghui; Wang, Lianjun; Jiang, Wan; Liu, Yong; Kong, Biao; Zhao, Dongyuan

    2016-09-28

    Nanostructured carbon materials have received considerable attention due to their special physicochemical properties. Herein, ordered mesoporous carbons (OMCs) with two-dimension (2D) hexagonal mesostructure and unique buckled large mesopores have successfully been synthesized via a micelle fusion-aggregation assembly method by using poly(ethylene oxide)-block-polystyrene (PEO-b-PS) diblock copolymers as a template and resorcinol-based phenolic resin as a carbon precursor. The obtained ordered mesoporous carbons possess unique fiber-like morphology, specific surface area of 571-880 m(2)/g, pore volume of 0.54 cm(3)/g and large mesopores (up to 36.3 nm) and high density of active sites (i.e., carboxylic groups) of 0.188/nm(2). Gas sensor based on the ordered mesoporous carbons exhibits an excellent performance in sensing NH3 at a low temperature with fast response (detection (<1 ppm), and good selectivity, due to the large pore sizes, high surface area and rich active sites in the carbon pore walls.

  7. The Methane to Carbon Dioxide Ratio Produced during Peatland Decomposition and a Simple Approach for Distinguishing This Ratio

    Science.gov (United States)

    Chanton, J.; Hodgkins, S. B.; Cooper, W. T.; Glaser, P. H.; Corbett, J. E.; Crill, P. M.; Saleska, S. R.; Rich, V. I.; Holmes, B.; Hines, M. E.; Tfaily, M.; Kostka, J. E.

    2014-12-01

    Peatland organic matter is cellulose-like with an oxidation state of approximately zero. When this material decomposes by fermentation, stoichiometry dictates that CH4 and CO2 should be produced in a ratio approaching one. While this is generally the case in temperate zones, this production ratio is often departed from in boreal peatlands, where the ratio of belowground CH4/CO2 production varies between 0.1 and 1, indicating CO2 production by a mechanism in addition to fermentation. The in situ CO2/CH4 production ratio may be ascertained by analysis of the 13C isotopic composition of these products, because CO2 production unaccompanied by methane production produces CO2 with an isotopic composition similar to the parent organic matter while methanogenesis produces 13C depleted methane and 13C enriched CO2. The 13C enrichment in the subsurface CO2 pool is directly related to the amount of if formed from methane production and the isotopic composition of the methane itself. Excess CO2 production is associated with more acidic conditions, Sphagnum vegetation, high and low latitudes, methane production dominated by hydrogenotrophic methane production, 13C depleted methane, and generally, more nutrient depleted conditions. Three theories have been offered to explain these observations— 1) inhibition of acetate utilization, acetate build-up and diffusion to the surface and eventual aerobic oxidation, 2) the use of humic acids as electron acceptors, and the 3) utilization of organic oxygen to produce CO2. In support of #3, we find that 13C-NMR, Fourier transform infrared (FT IR) spectroscopy, and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) clearly show the evolution of polysaccharides and cellulose towards more decomposed humified alkyl compounds stripped of organic oxygen utilized to form CO2. Such decomposition results in more negative carbon oxidation states varying from -1 to -2. Coincident with this reduction in oxidation state, is the

  8. How much Carbon is Stored in Deserts? AN Approach for the Chilean Atacama Desert Using LANDSAT-8 Products

    Science.gov (United States)

    Hernández, H. J.; Acuña, T.; Reyes, P.; Torres, M.; Figueroa, E.

    2016-06-01

    The Atacama Desert in northern Chile is known as the driest place on Earth, with an average rainfall of about 15 mm per year. Despite these conditions, it contains a rich variety of flora with hundreds of species characterised by their extraordinary ability to adapt to this extreme environment. These biotic components have a direct link to important ecosystem services, especially those related to carbon storage and sequestration. No quantitative assessment is currently available for these services and the role of the desert in this matter remains unclear. We propose an approach to estimate above-ground biomass (AGB) using Landsat-8 data, which we tested in the Taparacá region, located in the northern section of the desert. To calibrate and validate the models, we used field data from 86 plots and several spectral indexes (NDVI, EVI and SAVI) obtained from the provisional Landsat-8 Surface-reflectance products. We applied randomised branch sampling and allometry principles (non-destructive methods) to collect biomass samples for all plant biological types: wetlands, steppes, shrubs and trees. All samples were dried in an oven until they reached constant weight and the final values were used to extrapolate dry matter content (AGB) to each plot in terms of kg m-2. We used all available scenes from September 2014 to August 2015 to calculate the maximum, minimum and average value for each index in each pixel within this period. For modeling, we used the method based on classification and regression trees called random forest (RF), available in the statistical software R-Project. The explained variance obtained by the RF algorithm was around 80-85%, and it improved when a wetland vector layer was used as the predictive factor in the model to reach the range 85-90%. The mean error was 1.45 kg m-2 of dry matter. The best model was obtained using the maximum and mean values of SAVI and EVI indexes. We were able to estimate total biomass storage of around 8 million tons

  9. Photochemical Production of Dissolved Inorganic Carbon from Oceanic Colored Dissolved Organic Matter: a Gentle Approach to Measuring a new "Wild Card" Carbon Cycle Term

    Science.gov (United States)

    Zafiriou, O. C.; Wang, W.; Johnson, C. G.

    2004-12-01

    BACKGROUND: Massive oceanic photochemical remineralization (termed "photo-CO2") has been reported[1-3]: CDOM + hv -----> CO2 (DIC) CDOM = Colored Dissolved Organic Matter. DIC = Dissolved Inorganic Carbon. The oceanic carbon cycle cannot be understood without quantifying photo-CO2 fluxes and their sensitivity to environmental variables. The optical model of Johannessen implies a global marine photo-CO2 of ˜1015 mol C or 12 Gt C a-1[4]; Kieber and Mopper find photo-CO2 formation rates in the NW Sargasso Sea of ˜20 nmol kg-1 hr-1, extrapolating to ˜1.3 Gt C a-1[5-7; D. Kieber pers. comm, 2003]. CURRENT METHOD: To achieve essential sensitivity, Antonio, TX). 2. Johannessen, S., L. Ziolkowski and W. Miller (2000). (Abstracts of Pacifichem 2000, Vol. 1, ENVR-332). 3. Miller, W.L. and S.C. Johannessen (1999). Eos, Trans. Am. Geophys. Un., 80:0S93, Abstract 0521K-09 (2000 AGU-ASLO Ocean Sciences Meeting, January 24-28, 2000. 4. Johannessen, S. C.H. A photochemical sink for dissolved organic carbon in the ocean. Ph.D Thesis, Dalhousie University, CA. 179pp May, 2000. 5. Kieber, D. J., K. Mopper and J.G. Qian (1999). Trans. Am. Geophys. Un. 80: OS 128, Abstract #0522J-01 6. Kieber, D., K. Mopper and J. Qian (2000). Abstracts of Pacifichem 2000, Vol. 1, ENVR-28). 7. Kieber, D.J., K. Mopper, J. Qian and O.C. Zafiriou 8. Zeebe, R.E., D.B. Wolf-Gladrow and H. Jansen (1999). Mar.Chem. 65, 135-153. 9. Nelson, N.B, D. A. Siegel, and A.F. Michaels (1998) Deep-Sea Res. 45, 931-957.

  10. A mechanistic modelling and data assimilation approach to estimate the carbon/chlorophyll and carbon/nitrogen ratios in a coupled hydrodynamical-biological model

    Directory of Open Access Journals (Sweden)

    B. Faugeras

    2004-01-01

    Full Text Available The principal objective of hydrodynamical-biological models is to provide estimates of the main carbon fluxes such as total and export oceanic production. These models are nitrogen based, that is to say that the variables are expressed in terms of their nitrogen content. Moreover models are calibrated using chlorophyll data sets. Therefore carbon to chlorophyll (C:Chl and carbon to nitrogen (C:N ratios have to be assumed. This paper addresses the problem of the representation of these ratios. In a 1D framework at the DYFAMED station (NW Mediterranean Sea we propose a model which enables the estimation of the basic biogeochemical fluxes and in which the spatio-temporal variability of the C:Chl and C:N ratios is fully represented in a mechanical way. This is achieved through the introduction of new state variables coming from the embedding of a phytoplankton growth model in a more classical Redfieldian NNPZD-DOM model (in which the C:N ratio is assumed to be a constant. Following this modelling step, the parameters of the model are estimated using the adjoint data assimilation method which enables the assimilation of chlorophyll and nitrate data sets collected at DYFAMED in 1997.Comparing the predictions of the new Mechanistic model with those of the classical Redfieldian NNPZD-DOM model which was calibrated with the same data sets, we find that both models reproduce the reference data in a comparable manner. Both fluxes and stocks can be equally well predicted by either model. However if the models are coinciding on an average basis, they are diverging from a variability prediction point of view. In the Mechanistic model biology adapts much faster to its environment giving rise to higher short term variations. Moreover the seasonal variability in total production differs from the Redfieldian NNPZD-DOM model to the Mechanistic model. In summer the Mechanistic model predicts higher production values in carbon unit than the Redfieldian NNPZD

  11. Evaluation of paleovegetation changes in the northwest part of the Amazon region, Brazil: a carbon isotope approach in soils

    International Nuclear Information System (INIS)

    Full text. Numerous studies have focused on the understanding of the vegetation dynamics in the amazon region and its realtion to climate. The research approaches in these studies have involved the use of biological, geomorphologic and botanical tools, (1,2). Our approach involves the use of 13 and 14 C analyses in soil organic mater t infer past vegeation changes in the Amazon region (3). This is based on the distinct composition that characterize the C3 and C4 plants, that formed the different vegetation communities that exist in the Amazon region. 14 C used as a dating tool. This paper present data in soils collected in the Rondonia State, located in the northwestern part of the Amazon region. The soils were collected along a transect that include four distinct vegetation communities, ranging from a Cerrado type vegetation (southern part), dominated by C4 grasses, to a tropical forest (northern part). The soils types are Latossolo Vermelho Amarelo at the Cerrado, Cerrado-transition and forest-transition sites, and Podzolico Vermelho amarelo at the forest site. 14 C data obtained in total soil organic matter, humin fraction and charcoal indicate that the organic matterin these soils is at least Holocene in age. The forest and the forest-transition sites area characterized by typical δ 13 C profiles (-29 to -24 0/00), indicating the predominance of C3 plants during the past in this region. The Cerrado-transition sites show a significant change in δ 13 C from -27.5 0/00 at the surface to -19 0/00 at 30 cm. This value changed toward more depleted δ 13 C values at the 90-100 cm depth interval, reaching a value of -30 0/00 at 190-200 cm depth interval. This trend has to be associated to a change from a forest type vegetation (190-200 cm to 130-140 cm), to a vegetation community with a mayor influence of C4 palnts recorded i the interval between 110-120 to 20-23 cm depth. The δ 13 C values at the Cerrado sites are the more enriched ones observed in this study

  12. Investigating the organic carbon cycle and the anaerobic oxidation of methane in the Guaymas Basin: a biogeochemical approach

    Science.gov (United States)

    Cathalot, C.; Decker, C.; Caprais, J.; Ruffine, L.; Le Bruchec, J.; Olu, K.

    2013-12-01

    The Guaymas Basin is a pretty unique environment located in the Gulf of California and characterized by the emanation of fluids enriched in hydrocarbon, mainly methane, and sulfides. In this peculiar environment, both cold seeps and hydrothermal vents co-exist very closely, and are separated only by a few kilometers. In addition, highly productive surface waters and strong terrestrial inputs are responsible for strong sedimentation rates in this area. This special geological system allows for the development of various and complex macrofaunal and/or bacterial assemblages, based on chemosynthetic activity. These sea-bottom communities have been previously described [1,2] and several studies have demonstrated the occurrence of Anaerobic Oxidation of Methane (AOM) in the shallow sediment layers. Nevertheless, the quantification of the biogeochemical processes (e.g. rates, relative proportions) involved in both ecosystems in relation with the associated communities, and their role in the local organic carbon (OC) cycle is still lacking. Using a diagenetic modeling approach, this study aims at studying the OC production and recycling processes by describing the biogeochemical pathways and their associated rates in the ecosystems from the Guaymas Basin. Twelve stations presenting distinct biological assemblages (microbial mats, vesicomyids and bare sediment) were selected among both cold-seeps and hydrothermal vents sites from the Guaymas basin. A transport-reaction model including respiration, sulfate reduction, methanogenesis and AOM was developed and applied to each station. To constrain the model, at each station, cores were sampled using an ROV and the pore-waters extracted using Rhizon syringes. Pore-water concentrations of CH4, SO42-, Cl- and H2S were then measured. In addition, ex situ O2 microprofiles equipped with microsensors and in situ incubations using benthic chambers were performed to estimate the sediment uptake rates (O2, H2S, CH4). The overall dataset

  13. Technical Note: A novel approach to estimation of time-variable surface sources and sinks of carbon dioxide using empirical orthogonal functions and the Kalman filter

    Directory of Open Access Journals (Sweden)

    R. Zhuravlev

    2011-10-01

    Full Text Available In this work we propose an approach to solving a source estimation problem based on representation of carbon dioxide surface emissions as a linear combination of a finite number of pre-computed empirical orthogonal functions (EOFs. We used National Institute for Environmental Studies (NIES transport model for computing response functions and Kalman filter for estimating carbon dioxide emissions. Our approach produces results similar to these of other models participating in the TransCom3 experiment.

    Using the EOFs we can estimate surface fluxes at higher spatial resolution, while keeping the dimensionality of the problem comparable with that in the regions approach. This also allows us to avoid potentially artificial sharp gradients in the fluxes in between pre-defined regions. EOF results generally match observations more closely given the same error structure as the traditional method.

    Additionally, the proposed approach does not require additional effort of defining independent self-contained emission regions.

  14. Carbon dioxide emissions reduction in China's transport sector: A dynamic VAR (vector autoregression) approach

    International Nuclear Information System (INIS)

    Energy saving and carbon dioxide emission reduction in China is attracting increasing attention worldwide. At present, China is in the phase of rapid urbanization and industrialization, which is characterized by rapid growth of energy consumption. China's transport sector is highly energy-consuming and pollution-intensive. Between 1980 and 2012, the carbon dioxide emissions in China's transport sector increased approximately 9.7 times, with an average annual growth rate of 7.4%. Identifying the driving forces of the increase in carbon dioxide emissions in the transport sector is vital to developing effective environmental policies. This study uses Vector Autoregressive model to analyze the influencing factors of the changes in carbon dioxide emissions in the sector. The results show that energy efficiency plays a dominant role in reducing carbon dioxide emissions. Private vehicles have more impact on emission reduction than cargo turnover due to the surge in private car population and its low energy efficiency. Urbanization also has significant effect on carbon dioxide emissions because of large-scale population movements and the transformation of the industrial structure. These findings are important for the relevant authorities in China in developing appropriate energy policy and planning for the transport sector. - Highlights: • The driving forces of CO2 emissions in China's transport sector were investigated. • Energy efficiency plays a dominant role in reducing carbon dioxide emissions. • Urbanization has significant effect on CO2 emissions due to large-scale migration. • The role of private cars in reducing emissions is more important than cargo turnover

  15. A study of methods of carbon dioxide capture and sequestration - the sustainability of a photosynthetic bioreactor approach

    International Nuclear Information System (INIS)

    The world is faced with an intrinsic environmental responsibility, i.e. the minimisation of greenhouse gas emission to acceptable levels. This study seeks to explain the methods of carbon dioxide capture and sequestration and to discuss a line of research that may, in the future, help to reduce the greenhouse effect in a sustainable manner. The capture of carbon dioxide produced by combustion of fossil fuels used in electric generation can be achieved by amine scrubbing of the flue gases. This process is costly and may, in the future, be replaced by options such as membrane separation, molecular sieves or desiccant adsorption. Short term options of sequestration by direct injection into geologic or oceanic sinks are recognised as methods to reduce the carbon dioxide levels but do not address issues of sustainability. For this purpose, the topic of photosynthetic reaction, which has long been known as a natural process that can produce useful by-products of biomass, oxygen and hydrogen and can fix carbon dioxide, has been examined. In a controlled environment, such as a bio-reactor, micro-organisms capable of photosynthetic reactions may hold the key to reducing emissions in both an economically and environmentally sustainable manner. The design of such a laboratory scale reactor, described in this paper, may help researchers study the feasibility of implementing a larger scale economically sustainable system capable of sequestering significant quantities of carbon dioxide

  16. Climate extremes and the carbon cycle - a review using an integrated approach with regional examples for forests & native ecosystems -

    Science.gov (United States)

    Frank, D.; Reichstein, M.; Bahn, M.; Beer, C.; Ciais, P.; Mahecha, M.; Seneviratne, S. I.; Smith, P.; van Oijen, M.; Walz, A.

    2012-04-01

    The terrestrial carbon cycle provides an important biogeochemical feedback to climate and is itself particularly susceptible to extreme climate events. Climate extremes can override any (positive) effects of mean climate change as shown in European and recent US-American heat waves and dry spells. They can impact the structure, composition, and functioning of terrestrial ecosystems and have the potential to cause rapid carbon losses from accumulated stocks. We review how climate extremes like severe droughts, heat waves, extreme precipitation or storms can cause direct impacts on the CO2 fluxes [e.g. due to extreme temperature and/ or drought events] as well as lagged impacts on the carbon cycle [e.g. via an increased fire risk, or disease outbreaks and pest invasions]. The relative impact of the different climate extremes varies according to climate region and vegetation type. We present lagged effects on plant growth (and mortality) in the year(s) following an extreme event and their impacts on the carbon sequestration of forests and natural ecosystems. Comprehensive regional or even continental quantification with regard to extreme events is missing, and especially compound extreme events, the role of lagged effects and aspects of the return frequency are not studied enough. In a case study of a Mediterranean ecosystem we illustrate that the response of the net carbon balance at ecosystem level to regional climate change is hard to predict as interacting and partly compensating processes are affected and several processes which have the ability to substantially alter the carbon balance are not or not sufficiently represented in state-of-the-art biogeochemical models.

  17. Climate change, forest management and nitrogen deposition influence on carbon sequestration in forest ecosystems in Russia: simulation modelling approach

    Science.gov (United States)

    Komarov, Alexander; Kudeyarov, Valery; Shanin, Vladimir

    2014-05-01

    Russian land ecosystems occupy more than 1/9th global land area. Therefore its carbon budget is an essential contribution to the global carbon budget. The first rough estimate of carbon balance on Russian territory was made on comparison data on total soil respiration (Kudeyarov et. al., 1995) and NPP calculated on data on biological productivity of different ecosystems over Russia. The carbon balance was evaluated as a C-sink. Further estimates of Russian C budget by V.Kudeyarov et al., (2007) and I.Kurganova et al., (2010) were more correct and included soil microbial flux, and non-respiratory processes: fossil fuel, agriculture, forest fires and post-fire emissions, insect damage, etc. According to estimates the total C-sink of Russian territory for early nineties was about -0.8-1.0 Pg C per year. The later IIASA account developed by A.Shvidenko et al. (2010) has provided current estimates of C fluxes and storages in Russia and showed that its terrestrial ecosystems served as a net carbon sink of -0.5-0.7 PgC yr-1 during the last decade. Taking into account big uncertainties of determination of carbon balance constituents one can say that results by IIASA and our Institute are rather close. Resulting effect of two processes (sequestration and CO2 emission) can be analysed by mathematical modelling only. Corresponding system of models of organic matter dynamics in forest ecosystems EFIMOD was developed in our Institute last decade and applied in Russia and other countries for evaluation of impacts of climate changes, forest management and forest fires. The comparative simulations of carbon and nitrogen dynamics in the mixed forest ecosystems of Central Russia from different climatic zones and site conditions have been made. Three large forest areas with the total square of about 17,000 km2 distinct in environmental conditions were chosen. We used the data of the forest inventory for model initialization. Four simulation scenarios (without disturbances, with

  18. The role of herbaceous crops in soil carbon and nitrogen cycles in relation to soil management . methodological approaches and innovative technologies

    International Nuclear Information System (INIS)

    Soil organic matter is an important pool within the total organic carbon of the planet,being equal to twice that if the atmosphere and three times the biotic one.Organic carbon sequestration in agricultural soils is therefore considered one of the most effective tools to counterbalance the emission of CO2 from fossil fuels combustion. The role of below ground plant parts in carbon sequestration is much more difficult that of above.ground parts because of the open issues about the determination of root biometrics and root exhudates. Recent literature indicates that root biomass is probably much larger than classically believed and that root surface where exhudation occurs is also underestimated, and so is its role in the rhizosphere.The general objective of this thesis is the evaluation of carbon sequestration in sorghum as a function of soil management. A specific objective is to approach methodological problems relevant to the accurate quantification of the contribution of below ground plant structures to athmosferic carbon sequestration. This objective will be approached through a thorough review of the literature and an experimental setup with different soil management systems in relation to organic matter. In the review special attention is given to the applied tracer methods. The contribution of plant derived organic substances to the SOM turnover obtained with 13C natural abundance is also reviewed. A related objective is the monitoring of nitrogen dynamics discriminating the contribution of organic matter applied to the soil. In addition to organic C, soil may also contain inorganic C in the form of carbonates. This is of particular relevance to dry lands because calcification and formation of secondary carbonate is an important process in arid and semi-arid regions. Consequently the largest accumulations of carbonate occur in the soils of arid and semi-arid areas. Dynamics of the inorganic carbon pool are poorly understood although it is normally quite

  19. CO{sub 2} huff-n-puff process in a light oil shallow carbonate reservoir. Annual report, January 1, 1996--December 31, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Prieditis, J.; Wehner, S.

    1998-01-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration & Production Inc. and the U.S. Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg and San Andres formations; a light oil, shallow shelf carbonate reservoir that exists throughout the Permian Basin. A significant amount of oil reserves are located in carbonate reservoirs. Specifically, the carbonates deposited in shallow shelf (SSC) environments make up the largest percentage of known reservoirs within the Permian Basin of North America. Many of these known resources have been under waterflooding operations for decades and are at risk of abandonment if crude oil recoveries cannot be economically enhanced. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. Miscible CO{sub 2} flooding is the process of choice for enhancing recovery of light oils and already accounts for over 12% of the Permian Basin`s daily production. There are significant probable reserves associated with future miscible CO{sub 2} projects. However, many are marginally economic at current market conditions due to large up-front capital commitments for a peak response which may be several years in the future. The resulting negative cash-flow is sometimes too much for an operator to absorb. The CO{sub 2} H-n-P process is being investigated as a near-term option to mitigate the negative cash-flow situation--allowing acceleration of inventoried miscible CO{sub 2} projects when coupled together.

  20. From soilscapes to landscapes: A landscape-oriented approach to simulate soil organic carbon dynamics in intensively managed landscapes

    Science.gov (United States)

    Most available biogeochemical models focus within a soil profile and cannot adequately resolve contributions of the lighter size fractions of organic rich soils for Enrichment Ratio (ER) estimates, thereby causing unintended errors in Soil Organic Carbon (SOC) storage predictions. These models set E...

  1. Facile and green approach to prepare fluorescent carbon dots: Emergent nanomaterial for cell imaging and detection of vitamin B2.

    Science.gov (United States)

    Kundu, Aniruddha; Nandi, Sudipta; Das, Pradip; Nandi, Arun K

    2016-04-15

    Carbon dots (CDs) are a new representative in carbonaceous family and have initiated remarkable research interests over the past one decade in a large variety of fields. Herein, we have utilized a facile, one-step carbonization method to prepare fluorescent carbon dots using poly(vinyl alcohol) (PVA) both as a carbon source and as a surface passivating agent. The as prepared CDs emit bright blue fluorescence under ultraviolet illumination. The structure and optical properties of the CDs are thoroughly investigated by several methods such as high-resolution transmission electron microscopy; dynamic light scattering; UV-vis, fluorescence and Fourier transform infrared spectroscopy. The CDs exhibit excellent water solubility and demonstrate average hydrodynamic diameter of 11.3 nm, holding great promise for biological applications. The biocompatibility evaluation and in vitro imaging study reveals that the synthesized CDs can be used as effective fluorescent probes in bio-imaging without noticeable cytotoxicity. In addition, a unique sensor for the detection of vitamin B2 in aqueous solution is proposed on the basis of spontaneous fluorescence resonance energy transfer from CD to vitamin B2. These findings therefore suggest that the CDs can find potential applications in cellular imaging along with sensing of vitamin B2.

  2. Facile and green approach to prepare fluorescent carbon dots: Emergent nanomaterial for cell imaging and detection of vitamin B2.

    Science.gov (United States)

    Kundu, Aniruddha; Nandi, Sudipta; Das, Pradip; Nandi, Arun K

    2016-04-15

    Carbon dots (CDs) are a new representative in carbonaceous family and have initiated remarkable research interests over the past one decade in a large variety of fields. Herein, we have utilized a facile, one-step carbonization method to prepare fluorescent carbon dots using poly(vinyl alcohol) (PVA) both as a carbon source and as a surface passivating agent. The as prepared CDs emit bright blue fluorescence under ultraviolet illumination. The structure and optical properties of the CDs are thoroughly investigated by several methods such as high-resolution transmission electron microscopy; dynamic light scattering; UV-vis, fluorescence and Fourier transform infrared spectroscopy. The CDs exhibit excellent water solubility and demonstrate average hydrodynamic diameter of 11.3 nm, holding great promise for biological applications. The biocompatibility evaluation and in vitro imaging study reveals that the synthesized CDs can be used as effective fluorescent probes in bio-imaging without noticeable cytotoxicity. In addition, a unique sensor for the detection of vitamin B2 in aqueous solution is proposed on the basis of spontaneous fluorescence resonance energy transfer from CD to vitamin B2. These findings therefore suggest that the CDs can find potential applications in cellular imaging along with sensing of vitamin B2. PMID:26852351

  3. Predicting total organic carbon load with El Nino southern oscillation phase using hybrid and fuzzy logic approaches

    Science.gov (United States)

    During drinking water treatment chlorine reacts with total organic carbon (TOC) to form disinfection byproducts (DBP), some of which can be carcinogenic. Additional treatment required to remove TOC before chlorination significantly increases treatment cost. There are two main sources of TOC in a wat...

  4. New Approach to solving the Dilemma between Development and Carbon Reduction——An interview with Prof. DING Zhongli

    Institute of Scientific and Technical Information of China (English)

    DING Zhongli

    2009-01-01

    @@ Evolving from decades of international negotiations, "cap and trade" has been regarded as the best ever means to offset excessive greenhouse gases emitted by human societies. Nevertheless, this mechanism faces some difficulties in implementation and has so far failed to inspire a well-agreed international system of responsibility to reduce carbon emissions. It is even challenged by some scientists for its flawed presumption.

  5. A holistic approach in analyzing the impact of a carbon tax in the OECD: a framework for further discussions

    International Nuclear Information System (INIS)

    Carbon dioxide is one of the byproducts of burning fossil fuel and a major greenhouse effect gas, responsible for the anthropogenic climate change. To reduce the global warming from this perspective, will require calling on the doors of energy demand. It becomes obvious that energy demand will be influenced primarily by sustainable economic development in the medium term and by environmental considerations in the longer term. Measures being contemplated within the OECD to tackle global warming are mainly regulatory, economic, taxes, technological improvement, and change in social behaviour and attitude. The European Community has come up with a specific proposal of a carbon/energy tax. However, the energy exporting developing countries, where oil revenues are the major source for foreign exchange, capital formation and economic development, are worried. This paper examines the impacts of implementing a carbon tax to reduce carbon dioxide emissions and also analyze the effect of such on the use of non-commercial energy in developing countries. 9 refs., 4 tabs

  6. Tracing the sources and spatial distribution of organic carbon in subsoils using a multi-biomarker approach

    Science.gov (United States)

    Angst, Gerrit; John, Stephan; Mueller, Carsten W.; Kögel-Knabner, Ingrid; Rethemeyer, Janet

    2016-07-01

    Soil organic carbon (SOC) from aboveground and belowground sources has rarely been differentiated although it may drive SOC turnover and stabilization due to a presumed differing source dependent degradability. It is thus crucial to better identify the location of SOC from different sources for the parameterization of SOC models, especially in the less investigated subsoils. The aim of this study was to spatially assess contributions of organic carbon from aboveground and belowground parts of beech trees to subsoil organic carbon in a Dystric Cambisol. Different sources of SOC were distinguished by solvent-extractable and hydrolysable lipid biomarkers aided by 14C analyses of soil compartments carbon to the upper subsoil (leaf- and root-affected zone) indicate that supposedly fast-cycling, leaf-derived SOC may still be of considerable importance below the A-horizon. In the deeper subsoil (root-affected zone), roots were an important source of fresh SOC. Simultaneously, strongly increasing apparent 14C ages (3860 yrs BP) indicate considerable contribution of SOC that may be inherited from the Pleistocene parent material.

  7. Pore space characterization in carbonate rocks - Approach to combine nuclear magnetic resonance and elastic wave velocity measurements

    Science.gov (United States)

    Müller-Huber, Edith; Schön, Jürgen; Börner, Frank

    2016-04-01

    Pore space features influence petrophysical parameters such as porosity, permeability, elastic wave velocity or nuclear magnetic resonance (NMR). Therefore they are essential to describe the spatial distribution of petrophysical parameters in the subsurface, which is crucial for efficient reservoir characterization especially in carbonate rocks. While elastic wave velocity measurements respond to the properties of the solid rock matrix including pores or fractures, NMR measurements are sensitive to the distribution of pore-filling fluids controlled by rock properties such as the pore-surface-to-pore-volume ratio. Therefore a combination of both measurement principles helps to investigate carbonate pore space using complementary information. In this study, a workflow is presented that delivers a representative average semi-axis length of ellipsoidal pores in carbonate rocks based on the pore aspect ratio received from velocity interpretation and the pore-surface-to-pore-volume ratio Spor as input parameters combined with theoretical calculations for ellipsoidal inclusions. A novel method to calculate Spor from NMR data based on the ratio of capillary-bound to movable fluids and the thickness of the capillary-bound water film is used. To test the workflow, a comprehensive petrophysical database was compiled using micritic and oomoldic Lower Muschelkalk carbonates from Germany. The experimental data indicate that both mud-dominated and grain-dominated carbonates possess distinct ranges of petrophysical parameters. The agreement between the predicted and measured surface-to-volume ratio is satisfying for oomoldic and most micritic samples, while pyrite or significant sample heterogeneity may lead to deviations. Selected photo-micrographs and scanning electron microscope images support the validity of the estimated representative pore dimensions.

  8. A field measurement based scaling approach for quantification of major ions, organic carbon, and elemental carbon using a single particle aerosol mass spectrometer

    Science.gov (United States)

    Zhou, Yang; Huang, X. H. Hilda; Griffith, Stephen M.; Li, Mei; Li, Lei; Zhou, Zhen; Wu, Cheng; Meng, Junwang; Chan, Chak K.; Louie, Peter K. K.; Yu, Jian Zhen

    2016-10-01

    Single Particle Aerosol Mass Spectrometers (SPAMS) have been increasingly deployed for aerosol studies in Asia. To date, SPAMS is most often used to provide unscaled information for both the size and chemical composition of individual particles. The instrument's lack of accuracy is primarily due to only a fraction of particles being detected after collection, and the instrumental sensitivity is un-calibrated for various chemical species in mixed ambient aerosols. During a campaign from January to April 2013 at a coastal site in Hong Kong, the particle number information and ion intensity of major PM2.5 components collected by SPAMS were scaled by comparing with collocated bulk PM2.5 measurements of hourly or higher resolution. The bulk measurements include PM2.5 mass by a SHARP 5030 Monitor, major ions by a Monitor for Aerosols & Gases in ambient Air (MARGA), and organic carbon (OC) and elemental carbon (EC) by a Sunset OCEC analyzer. During the data processing, both transmission efficiency (scaled with the Scanning Mobility Particle Sizer) and hit efficiency conversion were considered, and component ion intensities quantified as peak area (PA) and relative peak area (RPA) were analyzed to track the performance. The comparison between the scaled particle mass assuming a particle density of 1.9 g cm-3 from SPAMS and PM2.5 concentration showed good correlation (R2 = 0.81) with a slope of 0.814 ± 0.004. Regression analysis results suggest an improved scaling performance using RPA compared with PA for most of the major PM2.5 components, including sulfate, nitrate, potassium, ammonium, OC and EC. Thus, we recommend preferentially scaling these species using the RPA. For periods of high K+ concentrations (>1.5 μg m-3), under-estimation of K+ by SPAMS was observed due to exceeding the dynamic range of the acquisition board. When only applying the hit efficiency correction, data for sulfate, nitrate, ammonium, potassium and OC were in reasonably good correlation (R2 = 0

  9. 低碳旅游概念辨识及其实现途径%Exploring the Concept of Low Carbon Tourism and Implementation Approaches

    Institute of Scientific and Technical Information of China (English)

    王谋

    2012-01-01

    Low-carbon tourism is becoming a hot issue along with the further implementation of energy saving projects and climate change programme in China. However, it remains a new concept and has little international experience for China in the definition, contents and approaches of identifying low-carbon tourism Wide range studies need to be deepened. Researches that have been conducted and distributed obviously provides very positive role to help with the understanding of the concept of low-carbon tourism, but they are not yet perfect and some misunderstandings are generated. Based on the summary of previous definitions and understanding of low-carbon tourism, this paper proposed that low-carbon tourism should be a concept that could simultaneously address development issue as well as greenhouse gas emission control. Low-earbon tourism is a new development model of tourism with very clear intention of climate and environment protection. There are several ways with different costs to approach low-carbon tourism other than simply constraining the consuming activity with energy and resources saving requirements, and policy-makers can make their decisions according to the resource endowment and domestic situation. Implementing low-carbon development at the current stage will face much more challenges than the traditional development model. However, we need to clearly realize that fossil fuel energy intensive development model should not be the future choice. Low-carbon tourism and low-carbon development are not only contributing to climate and energy security, but also to environment improvement. Low-earbon tourism can fulfill sustainable development requirement and need to be implemented step by step.%随着节能减排、应对气候变化等概念的实践和推广,低碳旅游也越来越多的被提及和实践.低碳旅游由于其新,无国际经验可循,在概念、内涵以及实现途径等方面认识还不够深入,甚至形成了一些认识的误区,实践中

  10. Erosion, deposition and replacement of soil organic carbon in Mediterranean catchments: a geomorphological, isotopic and land use change approach

    Directory of Open Access Journals (Sweden)

    E. Nadeu

    2011-08-01

    Full Text Available The assessment of the net effect of soil erosion on the global carbon budget is still incomplete because of lack of enough focused studies and field data. Two of the major gaps on our understanding of the erosion induced terrestrial carbon sink issue include rate of eroded soil organic carbon (OC replacement by production of new photosynthate and stability of eroded OC post deposition. Here we examine the effect of erosion processes and land use change on the stock, type and stability of OC in two medium-sized subcatchments (18 and 50 ha in size in SE Spain. We analysed soil samples from drainage areas and depositional settings for stock and isotopic composition of OC (14C and 13C and particle size distribution. In addition, we conducted land use change analysis for the period 1956–2008 and a geomorphological survey of the current erosion processes taking place in the slope-streambed connections. Our findings demonstrate how land use change influenced the dominating erosion processes and, thus, the source of eroding sediments. Carbon isotopes used as tracers revealed that in one of the subcatchments the deposited sediments derived from deep soil (average Δ14C of −271.5 ‰ through non-selective erosion processes. In the other subcatchment, topsoil material was predominantly eroded and the average Δ14C in sediments was −64.2 ‰. Replacement of eroded soil OC was positive (4 and 11 times-fold losses by erosion for the analyzed soil profiles in the slopes suggesting that erosion processes do not necessarily provoke a decrease in soil OC stock.

  11. The response of ecosystem carbon pools to management approaches that increase the growth of loblolly pine (Pinus taeda L.)

    Science.gov (United States)

    Vogel, J. G.; Bacon, A. R.; Bracho, R. G.; Grunwald, S.; Gonzalez-Benecke, C. A.; Jokela, E. J.; Markewitz, D.; Cucinella, J.; Akers, K.; Ross, C. W.; Peter, G. F.; Fox, T. D.; Martin, T.; Kane, M.

    2015-12-01

    Extending from Virginia to east Texas in the southeastern United States, managed pine forests are an important component of the region's carbon cycle. One objective of the Pine Integrated Network: Education, Mitigation, and Adaptation project (PINEMAP) is to improve estimates of how ecosystem carbon pools respond to the management strategies used to increase the growth of loblolly pine forests. Experimental studies (108 total) that had historically been used to understand forest productivity and stand dynamics by university-forest industry cooperatives have now been measured for the carbon stored in the trees, coarse-wood, forest floor, understory and soils to 1-meter (0-10 cm, 10-20 cm, 20-50 cm, and 50-100 cm). The age of the studied forests ranged from 4-26 years at the time of sampling, with 26 years very near the period when these forests are commonly harvested. The study sites encapsulated a wide regional range in precipitation (1080 mm -1780 mm) and potential evapotranspiration (716 mm - 1200 mm). The most prevalent three soil orders measured were Ultisols (62%), Alfisols (19%), and Spodosols (10%) with Entisols, Inceptisols and 1 Histosol making up the remainder (9%). Across all study sites, 455 experimental plots were measured. The plots had as a treatment either fertilization, competition control, and stand density control (thinning), including every possible combination of treatments and also 'no treatment'. The most common treatment regime, at 36% of the total number of plots, was the combination of competition control, fertilization, and thinning. The distribution of treatments relative to soils and climate prevented a simple analysis of single treatment effects and instead necessitated an examination how the carbon accumulation rate in wood, which is commonly measured and modeled in these forests, corresponded to the response of other C pools (e.g. forest floor and soil).

  12. Photocatalytic degradation of organic contaminants under solar light using carbon dot/titanium dioxide nanohybrid, obtained through a facile approach

    Science.gov (United States)

    Hazarika, Deepshikha; Karak, Niranjan

    2016-07-01

    In the present study, a novel, simple and green method was developed to synthesize highly luminescent nitrogen containing carbon dot (CD) using carbon resources like bio-based citric acid and glycerol in the presence of cost free cow urine. The as-synthesized CD showed exciting wavelength dependent down- and up-conversion flourescence properties. To utilize the advantage of up-conversion flourescence, a nanohybrid (CD@TiO2) was synthesized from the above carbon resources and titanium butoxide through a facile one pot single step hydrothermal protocol. Nanomaterials like bare TiO2 and nanohybrid of TiO2 in presence of CD (CD/TiO2) were also synthesized for comparison purpose. The optical properties and structural characteristics of the prepared CD, bare TiO2, CD@TiO2 and CD/TiO2 were examined by Fourier transform infrared (FTIR), UV-vis and fluorescence spectroscopic, scanning electron microscopic (SEM), transmission electron microscopic (TEM) and X-ray diffraction (XRD) studies. The elemental compositions of bare CD and CD@TiO2 nanohybrid were obtained from EDX analyses. The poor crystalline nature and narrow distribution of spherical CD and anatase form of TiO2 were confirmed from XRD and TEM studies. Amongst the studied nanomaterials, CD@TiO2 exhibited the most promising photocatalytic degradation of organic pollutants like benzene and phenol as well as an anthrogenic pesticide under sunlight.

  13. An analytical approach to evaluate the performance of graphene and carbon nanotubes for NH3 gas sensor applications

    Directory of Open Access Journals (Sweden)

    Elnaz Akbari

    2014-05-01

    Full Text Available Carbon, in its variety of allotropes, especially graphene and carbon nanotubes (CNTs, holds great potential for applications in variety of sensors because of dangling π-bonds that can react with chemical elements. In spite of their excellent features, carbon nanotubes (CNTs and graphene have not been fully exploited in the development of the nanoelectronic industry mainly because of poor understanding of the band structure of these allotropes. A mathematical model is proposed with a clear purpose to acquire an analytical understanding of the field-effect-transistor (FET based gas detection mechanism. The conductance change in the CNT/graphene channel resulting from the chemical reaction between the gas and channel surface molecules is emphasized. NH3 has been used as the prototype gas to be detected by the nanosensor and the corresponding current–voltage (I–V characteristics of the FET-based sensor are studied. A graphene-based gas sensor model is also developed. The results from graphene and CNT models are compared with the experimental data. A satisfactory agreement, within the uncertainties of the experiments, is obtained. Graphene-based gas sensor exhibits higher conductivity compared to that of CNT-based counterpart for similar ambient conditions.

  14. A comprehensive estimate of recent carbon sinks in China using both top-down and bottom-up approaches

    Science.gov (United States)

    Jiang, Fei; Chen, Jing; Zhou, Linxi; Ju, Weimin; Zhang, Huifang; Machida, Toshinobu; Ciais, Philippe; Peters, Wouter; Wang, Hengmao; Chen, Baozhang; Liu, Linxin; Zhang, Chunhua; Matsueda, Hidekazu; Sawa, Yousuke

    2016-04-01

    Atmospheric inversions use measurements of atmospheric CO2 gradients to constrain regional surface fluxes. Current inversions indicate a net terrestrial CO2 sink in China between 0.16 and 0.35 PgC/yr. The uncertainty of these estimates is as large as the mean because the atmospheric network historically contained only one high altitude station in China. Here, we revisit the calculation of the terrestrial CO2 flux in China, excluding emissions from fossil fuel burning and cement production, by using two inversions with three new CO2 monitoring stations in China as well as aircraft observations over Asia. We estimate a net terrestrial CO2 uptake of 0.39-0.51 PgC/yr with a mean of 0.45 PgC/yr in 2006-2009. After considering the lateral transport of carbon in air and water and international trade, the annual mean carbon sink is adjusted to 0.35 PgC/yr. To evaluate this top-down estimate, we constructed an independent bottom-up estimate based on ecosystem data, and giving a net land sink of 0.33 PgC/yr. This demonstrates closure between the top-down and bottom-up estimates. Both top-down and bottom-up estimates give a higher carbon sink than previous estimates made for the 1980s and 1990s, suggesting a trend towards increased uptake by land ecosystems in China.

  15. The CaCO3-Fe interaction: Kinetic approach for carbonate subduction to the deep Earth's mantle

    Science.gov (United States)

    Martirosyan, N. S.; Yoshino, T.; Shatskiy, A.; Chanyshev, A. D.; Litasov, K. D.

    2016-10-01

    The CaCO3-Fe0 system, as a model for redox reactions between carbonates and reduced lithologies at the slab-mantle interface during subduction or at core-mantle boundary, was investigated systematically at temperatures from 650 to 1400 °C and pressures from 4 to 16 GPa using multianvil apparatus. CaCO3 reduction via reaction: 3 CaCO3 (aragonite) + 13 Fe0 (metal) = Fe7C3 (carbide) + 3 CaFe2O3 (Ca-wüstite) was observed. The thickness of the reaction-product layer (Δx) increases linearly with the square root of time in the time-series experiments (t), indicating diffusion-controlled process. The reaction rate constant (k = Δx2/2t) is log-linear relative to 1/T. Its temperature dependences was determined to be k [m2/s] = 2.1 × 10-7exp(-162[kJ/mol]/RT) at 4-6 GPa and k [m2/s] = 2.6 × 10-11exp(-65[kJ/mol]/RT) at 16 GPa. The sluggish kinetics of established CaCO3-Fe0 interaction suggests that significant amount of carbonates could survive during subduction from metal saturation boundary near 250 km depth down to the transition zone and presumably to the lower mantle if melting of carbonates is not involved.

  16. Quantitative Characterization of the Interaction Space of the Mammalian Carbonic Anhydrase Isoforms I, II, VII, IX, XII, and XIV and their Inhibitors, Using the Proteochemometric Approach.

    Science.gov (United States)

    Rasti, Behnam; Karimi-Jafari, Mohammad H; Ghasemi, Jahan B

    2016-09-01

    The critical role of carbonic anhydrases in different physiological processes has put this protein family at the center of attention, challenging major diseases like glaucoma, neurological disorders such as epilepsy and Alzheimer's disease, obesity, and cancers. Many QSAR/QSPR (quantitative structure-activity/property relationship) researches have been carried out to design potent carbonic anhydrase inhibitors (CAIs); however, using inhibitors with no selectivity for different isoforms can lead to major side-effects. Given that QSAR/QSPR methods are not capable of covering multiple targets in a unified model, we have applied the proteochemometric approach to model the interaction space that governs selective inhibition of different CA isoforms by some mono-/dihydroxybenzoic acid esters. Internal and external validation methods showed that all models were reliable in terms of both validity and predictivity, whereas Y-scrambling assessed the robustness of the models. To prove the applicability of our models, we showed how structural changes of a ligand can affect the selectivity. Our models provided interesting information that can be useful for designing inhibitors with selective behavior toward isoforms of carbonic anhydrases, aiding in their selective inhibition. PMID:26990115

  17. Complexing Agents on Carbon Content and Lithium Storage Capacity of LiFePO4/C Cathode Synthesized via Sol-Gel Approach

    Directory of Open Access Journals (Sweden)

    C. Guan

    2016-01-01

    Full Text Available Olivine-structured LiFePO4 faces its intrinsic challenges in terms of poor electrical conductivity and lithium-ion diffusion capability for application to lithium-ion batteries. Cost-effective sol-gel approach is advantageous to in situ synthesize carbon-coated LiFePO4 (LiFePO4/C which can not only improve electronic conductivity but also constrain particle size to nanometer scale. In this study, the key parameter is focused on the choice and amount of chelating agents in this synthesis route. It was found that stability of complexing compounds has significant impacts on the carbon contents and electrochemical properties of the products. At the favorable choice of precursors, composition, and synthesis conditions, nanocrystalline LiFePO4/C materials with appropriate amount of carbon coating were successfully obtained. A reversible capacity of 162 mAh/g was achieved at 0.2C rate, in addition to good discharge rate capability.

  18. Synthesizing the Use of Carbon Isotope (14C and 13C) Approaches to Understand Rates and Pathways for Permafrost C Mobilization and Mineralization

    Science.gov (United States)

    Estop-Aragones, C.; Olefeldt, D.; Schuur, E.

    2015-12-01

    To better understand the permafrost carbon (C) feedback it is important to synthesize our current knowledge, and knowledge gaps, of how permafrost thaw can cause in situ mineralization or downstream mobilization of aged soil organic carbon (SOC) and the rate of this release. This potential loss of old SOC may occur via gaseous flux of CO2 and CH4 exchanged between soil and the atmosphere and via waterborne flux as DOC, POC (and their subsequent decomposition and release to the atmosphere). Carbon isotope (14C and 13C) approaches have been used to estimate both rates and pathways for permafrost C mobilization and mineralization. Radiocarbon (14C) has been used to estimate the contribution of aged C to overall respiration or waterborne C export. We aim to contrast results from radiocarbon studies, in order to assess differences between ecosystems (contrasting wet and dry ecosystems), thaw histories (active layer deepening or thermokarst landforms), greenhouse gas considered (CO2 and CH4) and seasons. We propose to also contrast methodologies used for assessing the contribution of aged C to overall C balance, and include studies using 13C data. Biological fractionation of 13C during both uptake and decomposition has been taken advantage of both in order to aid the interpretation of 14C data and on its own to assess sources and mineralization pathways. For example, 13C data has been used to differentiate between CH4 production pathways, and the relative contribution of anaerobic CO2 production to overall respiration. Overall, carbon isotope research is proving highly valuable for our understanding of permafrost C dynamics following thaw, and there is a current need to synthesize the available literature.

  19. Soil Organic Matter to Soil Organic Carbon ratios in recovered mountain peatlands using Vis-Nir spectroscopy approach.

    Science.gov (United States)

    Fernandez, Susana del Carmen; Valderrabano, Jesus; Peon, Juan Jose; Bueno, Alvaro

    2015-04-01

    The present research is part of a Life Project title "Inland Wetlands North of the Iberian Peninsula: Management and restoration of wetlands and hygrophilous environments" TREMEDAL (LIFE 11/ENV/ES/707) in which 25 wetland sites distributed by Galicia, Asturias, Castilla and León, País Vasco and Navarra were selected to be protected, restore or improve their conservation status and store seeds of bog plant species in the gene bank of Atlantic Botanic Garden of Gijon City, Spain. In Cantabrian Mountain Range two Poldjes (Glacio-Karstic depressions) site in Picos de Europa National Park were selected to develop an experimental action in the framework of the Life project. The selected sites harboring the most biodiverse peatland plant communities in the Cantabrian Mountain Range thus are in danger of extinction due to overgrazing. The action proposes the exclusion of livestock and wild herbivores in 5 parcels in order to contrast the differences in evolution of plant communities, hydrology and soil organic matter between grazed and non-grazed areas; and to determine future management measures that can reconcile traditional livestock raising with a better conservation of peatlands. The peatland are Vega of Liordes (Castilla-Leon) at an average altitude of 1868 m and filled mainly by clayed ferruginous sediments and Vega of Comella (Principality of Asturias) at an average altitude of 850 m and filled by at least 49 m of glacial and lacustrine sediments and 8 m of necromass from peatland vegetation. The soils developed are histosols under seasonal hydric regime in which the phreatic level suffers fluctuations over 30 cm along the year. At the time 0 (time fences were) 45 samples of the upper 15 cm of the histosols inside and outside the fences were taken. At the time 1 ( one year later) were re-sampled. Total organic carbon (TOC), Oxidizable Organic Carbon (OC), Carbonates presence and pH were analysis by chemical procedures. Also the Vis-Nir spectral analysis of the

  20. Modern Approach to the Synthesis of Ni(OH)2 Decorated Sulfur Doped Carbon Nanoparticles for the Nonenzymatic Glucose Sensor.

    Science.gov (United States)

    Karikalan, Natarajan; Velmurugan, Murugan; Chen, Shen-Ming; Karuppiah, Chelladurai

    2016-08-31

    As a growing aspect of materials science, there are an enormous number of synthesis routes that have been identified to produce materials, particularly through simple methodologies. In this way, the present study focuses on the easiest way to prepare sulfur doped carbon nanoparticles (SDCNs) using a flame synthesis method and has also demonstrated a novel route to synthesize Ni(OH)2 decorated SDCNs by a simple adsorption cum precipitation method. The SDCNs are alternative candidates to prestigious carbon materials such as graphene, carbon nanotubes, and fullerenes. Moreover, SDCNs provide excellent support to the Ni(2+) ion adsorption and initiate the formation of Ni(OH)2. The formation of Ni(OH)2 on the SDCN matrix was confirmed by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), selected area diffraction pattern (SAED), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). After these meticulous structural evaluations, we have described the mechanism for the formation of Ni(OH)2 on an SDCN matrix. The as-prepared Ni(OH)2 decorated SDCN nanocomposites were used as an electrode material for nonenzymatic glucose sensors. The fabricated glucose sensor exhibited a wide linear concentration range, 0.0001-5.22 mM and 5.22-10.22 mM, and a low-level detection limit of 28 nM. Additionally, it reveals excellent selectivity in the potentially interfering ions and also possesses a good stability. The practicality of the fabricated glucose sensor was also demonstrated toward glucose detection in biological samples. PMID:27519122

  1. Electronic interaction in composites of a conjugated polymer and carbon nanotubes: first-principles calculation and photophysical approaches

    Directory of Open Access Journals (Sweden)

    Florian Massuyeau

    2015-05-01

    Full Text Available The mechanisms that control the photophysics of composite films made of a semiconducting conjugated polymer (poly(paraphenylene vinylene, PPV mixed with single-walled carbon nanotubes (SWNT up to a concentration of 64 wt % are determined by using photoexcitation techniques and density functional theory. Charge separation is confirmed experimentally by rapid quenching of PPV photoluminescence and changes in photocurrent starting at relatively low concentrations of SWNT. Calculations predict strong electronic interaction between the polymer and the SWNT network when nanotubes are semiconducting.

  2. Building a low carbon scenario for France. How a participatory approach can enhance social and economic acceptability

    International Nuclear Information System (INIS)

    This publication presents the French case study of the European ENCI-LowCarb research project: Engaging Civil Society in Low Carbon scenarios. The core activity of this project was the development of a methodology for the transparent integration of stakeholders' contributions in the scenario design process to enhance the stakeholders' acceptance of the resulting low carbon pathways. This attempt at integrating acceptability in scenario-making constitutes an important step to distinguish what is technically and economically feasible from what is acceptable. Today, a wide range of published scenarios emphasize the fact that they are built on public consultations or stakeholders' contributions. However, transparency is lacking concerning the methodology relative to how contributions were taken into account and translated into assumptions that can be used by the modeling tool. The project ENCI-LowCarb aimed at exploring this scientific gap. Energy scenarios outline possible low-carbon futures built around assumptions on fossil fuels prices evolution, technological choices and the mechanisms of energy demand and supply, among others. Scenarios are influential tools in political decision-making processes since they shed light on the long-term impacts of today's investment decisions, especially regarding infrastructures. This is why it is crucial that these pathways derive from discussions with main stakeholders. In this report, the French project team (CIRED and RAC-F) has the pleasure to present energy scenarios for France which derive from a collaborative scenario design process including the participation of a wide range of French stakeholders (civil society organizations including trade unions and non-governmental organizations, private companies, banks, statewide and local authorities). Participating stakeholders were asked to define or select acceptable CO2 emissions mitigation measures. Their contributions were implemented in the technico-economic model Imaclim

  3. Linking water and carbon fluxes in a Mediterranean oak woodland using a combined flux and ?18O partitioning approach

    Science.gov (United States)

    Dubbert, M.; Piayda, A.; Costa e Silva, F.; Correia, A.; Pereira, J. S.; Cuntz, M.; Werner, C.

    2013-12-01

    Water is one of the key factors driving ecosystem productivity, especially in water-limited ecosystems, where global climate change is expected to intensify drought and alter precipitation patterns. One such ecosystem is the ';Montado', where two vegetation layers respond differently to drought: oak trees avoid drought due to their access to deeper soil layers and ground water while herbaceous plants, surviving the summer in the form of seeds. We aimed at 1) quantifying the impact of the understory herbaceous vegetation on ecosystem carbon and water fluxes throughout the year, 2) determining the driving environmental factors for evapotranspiration (ET) and net ecosystem exchange (NEE) and 3) disentangling how ET components of the ecosystem relate to carbon dioxide exchange. We present one year data set comparing modeled and measured stable oxygen isotope signatures (δ18O) of soil evaporation, confirming that the Craig and Gordon equation leads to good agreement with measured δ18O of evaporation (Dubbert et al. 2013). Partitioning ecosystem ET and NEE into its three sources revealed a strong contribution of soil evaporation (E) and herbaceous transpiration (T) to ecosystem ET during spring and fall. In contrast, soil respiration (R) and herbaceous net carbon gain contributed to a lesser amount to ecosystem NEE during spring and fall, leading to consistently smaller water use efficiencies (WUE) of the herbaceous understory compared to the cork-oaks. Here, we demonstrate that the ability to assess ET, NEE and WUE independent of soil evaporation dynamics enables the understanding of the mechanisms of the coupling between water and carbon fluxes and their responses to drought. Dubbert, M., Cuntz, M., Piayda, A., Maguas, C., Werner, C., 2013: Partitioning evapotranspiration - Testing the Craig and Gordon model with field measurements of oxygen isotope ratios of evaporative fluxes. J Hydrol. a) Oxygen isotope signatures of soil evaporation on bare soil plots calculated

  4. The utilization of the microflora indigenous to and present in oil-bearing formations to selectively plug the more porous zones thereby increasing oil recovery during waterflooding, Class 1

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, James O.; Brown, Lewis R.; Vadie, A. Alex

    2000-02-02

    The objectives of this project were (1) to demonstrate the in situ microbial population in a fluvial dominated deltaic reservoir could be induced to proliferate to such an extent that they will selectively restrict flow in the more porous zones in the reservoir thereby forcing injection water to flow through previously unswept areas thus improving the sweep efficiency of the waterflood and (2) to obtain scientific validation that microorganisms are indeed responsible for the increased oil recovery. One expected outcome of this new technology was the prolongation of economical life of the reservoir, i.e. economical oil recovery should continue for much longer periods in areas of the reservoir subjected to the MPPM technology than it would if it followed its historic trend.

  5. Characterization and Alteration of Wettability States of Alaskan Reserviors to Improve Oil Recovery Efficiency (including the within-scope expansion based on Cyclic Water Injection - a pulsed waterflood for Enhanced Oil Recovery)

    Energy Technology Data Exchange (ETDEWEB)

    Abhijit Dandekar; Shirish Patil; Santanu Khataniar

    2008-12-31

    Numerous early reports on experimental works relating to the role of wettability in various aspects of oil recovery have been published. Early examples of laboratory waterfloods show oil recovery increasing with increasing water-wetness. This result is consistent with the intuitive notion that strong wetting preference of the rock for water and associated strong capillary-imbibition forces gives the most efficient oil displacement. This report examines the effect of wettability on waterflooding and gasflooding processes respectively. Waterflood oil recoveries were examined for the dual cases of uniform and non-uniform wetting conditions. Based on the results of the literature review on effect of wettability and oil recovery, coreflooding experiments were designed to examine the effect of changing water chemistry (salinity) on residual oil saturation. Numerous corefloods were conducted on reservoir rock material from representative formations on the Alaska North Slope (ANS). The corefloods consisted of injecting water (reservoir water and ultra low-salinity ANS lake water) of different salinities in secondary as well as tertiary mode. Additionally, complete reservoir condition corefloods were also conducted using live oil. In all the tests, wettability indices, residual oil saturation, and oil recovery were measured. All results consistently lead to one conclusion; that is, a decrease in injection water salinity causes a reduction in residual oil saturation and a slight increase in water-wetness, both of which are comparable with literature observations. These observations have an intuitive appeal in that water easily imbibes into the core and displaces oil. Therefore, low-salinity waterfloods have the potential for improved oil recovery in the secondary recovery process, and ultra low-salinity ANS lake water is an attractive source of injection water or a source for diluting the high-salinity reservoir water. As part of the within-scope expansion of this project

  6. Probabilistic Approach to Determining Unbiased Random-coil Carbon-13 Chemical Shift Values from the Protein Chemical Shift Database

    International Nuclear Information System (INIS)

    We describe a probabilistic model for deriving, from the database of assigned chemical shifts, a set of random coil chemical shift values that are 'unbiased' insofar as contributions from detectable secondary structure have been minimized (RCCSu). We have used this approach to derive a set of RCCSu values for 13Cα and 13Cβ for 17 of the 20 standard amino acid residue types by taking advantage of the known opposite conformational dependence of these parameters. We present a second probabilistic approach that utilizes the maximum entropy principle to analyze the database of 13Cα and 13Cβ chemical shifts considered separately; this approach yielded a second set of random coil chemical shifts (RCCSmax-ent). Both new approaches analyze the chemical shift database without reference to known structure. Prior approaches have used either the chemical shifts of small peptides assumed to model the random coil state (RCCSpeptide) or statistical analysis of chemical shifts associated with structure not in helical or strand conformation (RCCSstruct-stat). We show that the RCCSmax-ent values are strikingly similar to published RCCSpeptide and RCCSstruct-stat values. By contrast, the RCCSu values differ significantly from both published types of random coil chemical shift values. The differences (RCCSpeptide-RCCSu) for individual residue types show a correlation with known intrinsic conformational propensities. These results suggest that random coil chemical shift values from both prior approaches are biased by conformational preferences. RCCSu values appear to be consistent with the current concept of the 'random coil' as the state in which the geometry of the polypeptide ensemble samples the allowed region of (φ,ψ)-space in the absence of any dominant stabilizing interactions and thus represent an improved basis for the detection of secondary structure. Coupled with the growing database of chemical shifts, this probabilistic approach makes it possible to refine

  7. Modeling the spatial distribution of above-ground carbon in Mexican coniferous forests using remote sensing and a geostatistical approach

    Science.gov (United States)

    Galeana-Pizaña, J. Mauricio; López-Caloca, Alejandra; López-Quiroz, Penélope; Silván-Cárdenas, José Luis; Couturier, Stéphane

    2014-08-01

    Forest conservation is considered an option for mitigating the effect of greenhouse gases on global climate, hence monitoring forest carbon pools at global and local levels is important. The present study explores the capability of remote-sensing variables (vegetation indices and textures derived from SPOT-5; backscattering coefficient and interferometric coherence of ALOS PALSAR images) for modeling the spatial distribution of above-ground biomass in the Environmental Conservation Zone of Mexico City. Correlation and spatial autocorrelation coefficients were used to select significant explanatory variables in fir and pine forests. The correlation for interferometric coherence in HV polarization was negative, with correlations coefficients r = -0.83 for the fir and r = -0.75 for the pine forests. Regression-kriging showed the least root mean square error among the spatial interpolation methods used, with 37.75 tC/ha for fir forests and 29.15 tC/ha for pine forests. The results showed that a hybrid geospatial method, based on interferometric coherence data and a regression-kriging interpolator, has good potential for estimating above-ground biomass carbon.

  8. Underground coal gasification with extended CO2 utilization as economic and carbon neutral approach to address energy and fertilizer supply shortages in Bangladesh

    Science.gov (United States)

    Nakaten, Natalie; Islam, Rafiqul; Kempka, Thomas

    2014-05-01

    The application of underground coal gasification (UCG) with proven carbon mitigation techniques may provide a carbon neutral approach to tackle electricity and fertilizer supply shortages in Bangladesh. UCG facilitates the utilization of deep-seated coal seams, not economically exploitable by conventional coal mining. The high-calorific synthesis gas produced by UCG can be used for e.g. electricity generation or as chemical raw material for hydrogen, methanol and fertilizer production. Kempka et al. (2010) carried out an integrated assessment of UCG operation, demonstrating that about 19 % of the CO2 produced during UCG may be mitigated by CO2 utilization in fertilizer production. In the present study, we investigated an extension of the UCG system by introducing excess CO2 storage in the gas deposit of the Bahkrabad gas field (40 km east of Dhaka, Bangladesh). This gas field still holds natural gas resources of 12.8 million tons of LNG equivalent, but is close to abandonment due to a low reservoir pressure. Consequently, applying enhanced gas recovery (EGR) by injection of excess carbon dioxide from the coupled UCG-urea process may mitigate carbon emissions and support natural gas production from the Bahkrabad gas field. To carry out an integrated techno-economic assessment of the coupled system, we adapted the techno-economic UCG-CCS model developed by Nakaten et al. (2014) to consider the urea and EGR processes. Reservoir simulations addressing EGR in the Bakhrabad gas field by utilization of excess carbon dioxide from the UCG process were carried out to account for the induced pressure increase in the reservoir, and thus additional gas recovery potentials. The Jamalganj coal field in Northwest Bangladesh provides favorable geological and infrastructural conditions for a UCG operation at coal seam depths of 640 m to 1,158 m. Excess CO2 can be transported via existing pipeline networks to the Bahkrabad gas field (about 300 km distance from the coal deposit) to be

  9. A Geochemical Approach for Monitoring a CO2 Pilot Site: Rousse, France. A Major gases, CO2-Carbon Isotopes and Noble Gases Combined Approach

    International Nuclear Information System (INIS)

    This paper presents the geochemical characterization of various gas end-members involved in a depleted gas field CO2 storage pilot (Rousse, France). In this pilot, CO2 is produced by oxy-combustion from natural gas transformed into fuel gas at the Lacq plant, and transported in a pipeline 30 km away to the depleted gas reservoir of Rousse. Gases produced at Rousse before CO2 injection, the Lacq fuel gas and the CO2 resulting from the oxy-fuel combustion were sampled, together with gases from a - 45 m monitoring well and from soils in the vicinity of the Rousse structure. For all samples, the bulk gas composition, the carbon isotopic compositions and the abundance and isotopic signatures of the noble gases were determined. The bulk gas compositions of the Rousse natural gas are comparable to the Lacq fuel gas with methane as the main compound with residual C2-C5 and CO2. Soil gases are typical mixtures of air with biogenic CO2 (up to 9-10%), while the monitoring well gases display typical air compositions with no excess CO2. The Rousse gas and the Lacq fuel gas have δ13(CH4) values of - 41.0 per thousand and - 43.0 per thousand respectively. The injected CO2 out of the oxy-combustion chamber has a δ13(CO2) of - 40.0 per thousand, whereas δ13(CO2) value for soils samples is comprised between - 15 and - 25 per thousand. The Rousse natural gas and the Lacq fuel gas are both characterized by a high He enrichment, and depletion in Ne, Ar and Kr compared to the air values. The oxy-fuel combustion process provides a CO2 with the He enrichment of the Lacq fuel gas, and a Ne, Ar and Kr composition reflecting that of the oxygen produced at the Air Separation Unit (ASU). Indeed, Ne is depleted relatively to the air, while Kr is enriched up to tenfold, which results from the cryogenic separation of the air noble gases within the ASU. Soil samples noble gas compositions are equivalent to that of the air. In the light of these results, the compositions of the various end

  10. Algal biorefinery-based industry: an approach to address fuel and food insecurity for a carbon-smart world.

    Science.gov (United States)

    Subhadra, Bobban

    2011-01-15

    Food and fuel production are intricately interconnected. In a carbon-smart society, it is imperative to produce both food and fuel sustainably. Integration of the emerging biorefinery concept with other industries can bring many environmental deliverables while mitigating several sustainability-related issues with respect to greenhouse gas emissions, fossil fuel usage, land use change for fuel production and future food insufficiency. A new biorefinery-based integrated industrial ecology encompasses the different value chain of products, coproducts, and services from the biorefinery industries. This paper discusses a framework to integrate the algal biofuel-based biorefinery, a booming biofuel sector, with other industries such as livestock, lignocellulosic and aquaculture. Using the USA as an example, this paper also illustrates the benefits associated with sustainable production of fuel and food. Policy and regulatory initiatives for synergistic development of the algal biofuel sector with other industries can bring many sustainable solutions for the future existence of mankind. PMID:20981716

  11. A facile and novel approach towards carboxylic acid functionalization of multiwalled carbon nanotubes and efficient water dispersion

    KAUST Repository

    Rehman, Ata Ur

    2013-10-01

    A convenient, cheap and mild covalent functionalization route for multiwalled carbon nanotubes (MWCNTs) have been developed for the first time. The MWCNTs were treated with wet chemical oxidants (NaNO2/HCl, HNO3/H2O2) in order to modify MWCNTs with carboxyl groups. Surface functionality groups and morphology of MWCNTs were analyzed by FTIR, TGA, SEM and TEM. The results consistently confirmed the formation of carboxyl functionalities on MWCNTs, while the structure of MWCNTs has remained relatively intact. Functionalized MWCNTs showed good dispersion in aqueous media than untreated MWCNTs. Results show that NaNO2/HCl treatment is best suited for the chemical functionalization, giving optimum surface carboxyl groups and minimum length shortening of MWCNTs. © 2013 Elsevier B.V.

  12. Testing new approaches to carbonate system simulation at the reef scale: the ReefSam model first results, application to a question in reef morphology and future challenges.

    Science.gov (United States)

    Barrett, Samuel; Webster, Jody

    2016-04-01

    Numerical simulation of the stratigraphy and sedimentology of carbonate systems (carbonate forward stratigraphic modelling - CFSM) provides significant insight into the understanding of both the physical nature of these systems and the processes which control their development. It also provides the opportunity to quantitatively test conceptual models concerning stratigraphy, sedimentology or geomorphology, and allows us to extend our knowledge either spatially (e.g. between bore holes) or temporally (forwards or backwards in time). The later is especially important in determining the likely future development of carbonate systems, particularly regarding the effects of climate change. This application, by its nature, requires successful simulation of carbonate systems on short time scales and at high spatial resolutions. Previous modelling attempts have typically focused on the scales of kilometers and kilo-years or greater (the scale of entire carbonate platforms), rather than at the scale of centuries or decades, and tens to hundreds of meters (the scale of individual reefs). Previous work has identified limitations in common approaches to simulating important reef processes. We present a new CFSM, Reef Sedimentary Accretion Model (ReefSAM), which is designed to test new approaches to simulating reef-scale processes, with the aim of being able to better simulate the past and future development of coral reefs. Four major features have been tested: 1. A simulation of wave based hydrodynamic energy with multiple simultaneous directions and intensities including wave refraction, interaction, and lateral sheltering. 2. Sediment transport simulated as sediment being moved from cell to cell in an iterative fashion until complete deposition. 3. A coral growth model including consideration of local wave energy and composition of the basement substrate (as well as depth). 4. A highly quantitative model testing approach where dozens of output parameters describing the reef

  13. Covalent functionalization of single-walled carbon nanotubes with anthracene by green chemical approach and their temperature dependent magnetic and electrical conductivity studies

    Energy Technology Data Exchange (ETDEWEB)

    Hariharasubramanian, A. [Organic Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu (India); Dominic Ravichandran, Y., E-mail: ydominic64@yahoo.co.in [Organic Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu (India); Rajesh, R.; Rajendra Kumar, K. [Organic Chemistry Division, School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu (India); Kanagaraj, M.; Arumugam, S. [Centre for High Pressure Research, School of Physics, Bharathidasan University, Thiruchirapalli 620024 (India)

    2014-01-15

    Single-walled carbon nanotubes (SWCNTs) were covalently functionalized with anthracene in molten urea by a green chemical approach. The anthracene functionalized single-walled carbon nanotubes (Ant-f-SWCNTs) were examined along with SWCNTs, using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, powder X-Ray diffraction (XRD), and scanning, and transmission electron microscopy. The observations revealed the functionalization of SWCNTs by anthracene. The temperature dependent magnetization (300–5 K) and electrical resistivity were also measured for both SWCNTs and Ant-f-SWCNTs. The electrical resistivity of Ant-f-SWCNTs at 300 K was found to be 1.27 KΩm, which is much lower than 388.55 KΩm for pristine. This indicated a 300 fold increase in conductivity at room temperature for Ant-f-SWCNTs when compared to SWCNTs. The temperature dependence of the conductivity provided an indication of the semiconducting behaviour. - Highlights: • SWCNTs were functionalized using 2-aminoanthracene by green chemistry. • Characterized by FTIR, Raman, XRD, SEM and TEM. • Temperature dependent magnetization and conductivity were investigated. • 300 fold increase in conductivity was observed for Ant-f-SWCNTs. • Semiconductor behaviour was observed in the case of Ant-f-SWCNTs.

  14. A facile one-pot self-assembly approach to incorporate SnOx nanoparticles in ordered mesoporous carbon with soft templating for fuel cells

    Science.gov (United States)

    Huang, Yingqiang; Zhai, Zhicheng; Luo, Zhigang; Liu, Yingju; Liang, Zhurong; Fang, Yueping

    2014-04-01

    Unique SnOx (x = 1,2)/ordered mesoporous carbon nanocomposites (denoted as SnOx/OMC) are firstly synthesized through a ‘one-pot’ synthesis together with the soft template self-assembly approach. The obtained SnOx/OMC nanocomposites with various SnOx contents exhibit uniform pore sizes between 3.9 and 4.2 nm, high specific surface areas between 497 and 595 m2 g-1, and high pore volumes between 0.39 and 0.48 cm3 g-1. With loading of Pt, Pt-SnOx/OMC with relatively low SnOx content exhibits superior electrocatalytic performance, long-term durability, and resistance to CO poisoning for methanol oxidation, as compared to Pt/OMC, PtRu/C and Pt-SnOx/C, which may be attributed not only to the synergetic effect of embedded SnOx, but also to the highly ordered mesostructure with high specific surface areas and large pore volumes affording plenty of surface area for support of Pt nanoparticles. This work supplies an efficient way to synthesize novel ordered mesoporous carbon self-supported metallic oxide as catalyst support and its further potential application to reduce the cost of catalysts in direct methanol fuel cells.

  15. A multiproxy approach to constrain the source, composition and reactivity of sedimentary organic carbon in the eastern Yellow Sea (the northwestern Pacific)

    Science.gov (United States)

    Yoon, SukHee; Kim, JunHyun; Lee, DongHun; Yi, HiiIl; Yamamoto, Masanobu; Gal, JonKu; Choi, BoHyung; Kang, Sujin; Shin, KyungHoon

    2016-04-01

    We investigated the source, composition and reactivity of sedimentary organic carbon (OC) in a river-dominated continental marginal sea, the eastern Yellow Sea. A multi-proxy approach was applied to 9 riverbank sediments and 69 marine surface sediments, combining bulk and molecular organic parameters. The sedimentary OC in the marine surface sediments appears to have a predominantly marine origin (on average C/N ratio=7.0±0.6 and δ13CTOC=-21.9±0.5‰, n=69) with minor contribution of continental (i.e. soil- and lake/river-derived) OC (on average BIT index=0.00±0.01, n=69). However, the 14C values were depleted (on average -227±53‰, n=8), indicating that about 18-33% of ancient OC, potentially derived from erosion of sedimentary bedrocks or from fossil fuels such as petroleum might be added to the sedimentary OC pool. The possible contribution of petroleum-derived OC was confirmed by Carbon preference indices (CPI) of n-alkanes (<1). Accordingly, our results highlight an important contribution of ancient OC in the eastern Yellow Sea. Nonetheless, more work is needed to better constrain the source, composition, and age of the organic material supplied to the eastern Yellow Sea, given the lack of biogeochemical data from the Korean rivers.

  16. Long term carbon dioxide exchange above a mixed forest in the Belgian Ardennes: evaluation of different approaches to deduce total ecosystem respiration from Eddy covariance measurements

    Science.gov (United States)

    Jérôme, Elisabeth; Aubinet, Marc; Heinesch, Bernard

    2010-05-01

    The general aim of this research is to analyze inter annual variability of carbon dioxide (CO2) fluxes exchanged by a mixed forest located at the Vielsalm experimental site in Belgium. At this site, CO2 flux measurements started in 1996 and are still going on. Thirteen complete years of measurements are thus available. Net Ecosystem Exchange (NEE) inter annual variability may be driven by gross primary productivity (GPP) or Total Ecosystem Respiration (TER), which should thus be both quantified. Using flux partitioning methods, TER is deduced from NEE measurements. GPP is then obtained by subtracting TER from NEE. Initially, a robust estimation of TER is required. This work seeks to compare two independent approaches to assess TER in order to quantify the implications on inter-annual variability. The comparison was performed on twelve complete years. TER estimates can be deduced by extrapolating to the whole day NEE measurements taken during selected night or day periods. In both case, the extrapolation is performed by using a respiration response to temperature. The first approach, referred as the night-time approach, consisted in calculating TER using a temperature response function derived from night-time data sets (Reichstein et al., 2005). The second approach, referred as the daytime approach, consisted in assessing TER from the intercept of the NEE/Photosynthetically Photon Flux Density (PPFD) response (Wohlfahrt et al., 2005). For each approach, different modalities were compared: the use of long term (annual) or short term (15 days) data sets for the night-time approach and the use of different types of regression for the daytime approach. In addition, the impact of the temperature choice was studied for each of the approaches. For the night-time approach, main results showed that air temperature sensitivity of ecosystem respiration derived from annual data did not reflect the short-term air temperature sensitivity. Vielsalm is a summer active ecosystem

  17. A new observational approach to investigate the heliospheric interstellar wind interface - The study of extreme and far ultraviolet resonantly scattered solar radiation from neon, oxygen, carbon and nitrogen

    Science.gov (United States)

    Bowyer, Stuart; Fahr, Hans J.

    1990-01-01

    One of the outstanding uncertainties in the understanding of the heliosphere concerns the character of the interaction between the outflowing solar wind and the interstellar medium. A new possibility for obtaining information on this topic is suggested. The cosmically abundant elements neon, oxygen, carbon, and nitrogen will be affected differently at their interface passage depending upon the character of this region. Consequently, the distribution of these atoms and their ions will vary within the inner heliosphere. The study of resonantly scattered solar radiation from these species will then provide information on the nature of the interface. A preliminary evaluation of this approach has been carried out, and the results are encouraging. The relevant lines to be studied are in the extreme and far ulraviolet. The existing data in these bands are reviewed; unfortunately, past instrumentation has had insufficient resolution and sensitivity to provide useful information. The capabilities of future approved missions with capabilities in this area are evaluated.

  18. A combined salt-hard templating approach for synthesis of multi-modal porous carbons used for probing the simultaneous effects of porosity and electrode engineering on EDLC performance

    KAUST Repository

    Bhandari, Nidhi

    2015-06-01

    A new approach, based on a combination of salt and hard templating for producing multi-modal porous carbons is demonstrated. The hard template, silica nanoparticles, generate mesopores (∼22 nm), and in some cases borderline-macropores (∼64 nm), resulting in high pore volume (∼3.9 cm3/g) while the salt template, zinc chloride, generates borderline-mesopores (∼2 nm), thus imparting high surface area (∼2100 m2/g). The versatility of the proposed synthesis technique is demonstrated using: (i) dual salt templates with hard template resulting in magnetic, nanostructured-clay embedded (∼27% clay content), high surface area (∼1527 m2/g) bimodal carbons (∼2 and 70 nm pores), (ii) multiple hard templates with salt template resulting in tri-modal carbons (∼2, 12 and 28 nm pores), (iii) low temperature (450 °C) synthesis of bimodal carbons afforded by the presence of hygroscopic salt template, (iv) easy coupling with physical activation approaches. A selected set of thus synthesized carbons were used to evaluate, for the first time, the simultaneous effects of carbon porosity and pressure applied during electrode fabrication on EDLC performance. Electrode pressing was found to be more favorable for carbons containing hard-templated mesopores (∼87% capacitance retention at current density of 40 A/g) as compared to those without (∼54% capacitance retention). © 2015 Elsevier Ltd. All rights reserved.

  19. Experimental validation of an effective carbon number-based approach for the gas chromatography-mass spectrometry quantification of 'compounds lacking authentic standards or surrogates'.

    Science.gov (United States)

    Kim, Yong-Hyun; Kim, Ki-Hyun; Szulejko, Jan E; Bae, Min-Suk; Brown, Richard J C

    2014-06-01

    For the quantitative analysis of 'compounds lacking authentic standards or surrogates' (CLASS) in environmental media, we previously introduced an effective carbon number (ECN) approach to develop an empirical equation for the prediction of their response factor (RF). In this research, a series of laboratory experiments were carried out to benchmark the reliability of an ECN approach for sorbent tube/thermal desorption/gas chromatography (GC)/mass spectrometry (MS) applications. First, the ECN values were determined using external calibration data from 25 reference volatile organic compounds (VOCs) using two MS dectectors (quadrupole (Q) and time-of-flight (TOF)). Then, a certified standard mixture of 54 VOCs was analyzed by each system as a simulated unknown sample. The analytical bias, assessed in terms of percentage difference (PD) between the certified and ECN-predicted mass values, averaged 19.2±16.1% (TOF-MS) and 28.2±27.6% (Q-MS). The bias using a more simplified carbon number (CN)-based prediction increased considerably, yielding 53.4±53.3% (TOF-MS) and 61.7±81.3% (Q-MS). However, the bias obtained using the ECN-based prediction decreased significantly to yield average PD values of 9.84±7.28% (TOF-MS) and 16.8±8.35% (Q-MS), if the comparison was limited to 26 (out of 54) VOCs with CN≥4 (i.e., 25 aromatics and hexachlorobutadiene). PMID:24856509

  20. Production and in vitro characterization of 3D porous scaffolds made of magnesium carbonate apatite (MCA)/anionic collagen using a biomimetic approach

    Energy Technology Data Exchange (ETDEWEB)

    Sader, Marcia S., E-mail: msader@metalmat.ufrj.br [Prog. Engenharia Metalúrgica e Materiais, COPPE/UFRJ, RJ (Brazil); Martins, Virginia C.A. [Depto. de Química e Física Molecular, IQSC/USP, SP (Brazil); Gomez, Santiago [Dept. Anatomía Patológica, Universidad de Cádiz, Cadiz (Spain); LeGeros, Racquel Z. [Department of Biomaterials and Biomimetics, New York University College of Dentistry, NY (United States); Soares, Gloria A. [Prog. Engenharia Metalúrgica e Materiais, COPPE/UFRJ, RJ (Brazil)

    2013-10-15

    3D porous scaffolds are relevant biomaterials to bone engineering as they can be used as templates to tissue reconstruction. The aim of the present study was to produce and characterize in vitro 3D magnesium-carbonate apatite/collagen (MCA/col) scaffolds. They were prepared by using biomimetic approach, followed by cross-linking with 0.25% glutaraldehyde solution (GA) and liofilization. Results obtained with Fourier-transform infrared spectroscopy (FT-IR) confirmed the type-B carbonate substitution, while by X-ray diffraction (XRD), a crystallite size of ∼ 10 nm was obtained. Optical and electron microscopy showed that the cylindrical samples exhibited an open-porous morphology, with apatite nanocrystals precipitated on collagen fibrils. The cross-linked 3D scaffolds showed integrity when immersed in culture medium up to 14 days. Also, the immersion of such samples into an acid buffer solution, to mimic the osteoclastic resorption environment, promotes the release of important ions for bone repair, such as calcium, phosphorus and magnesium. Bone cells (SaOs2) adhered, and proliferated on the 3D composite scaffolds, showing that synthesis and the cross-linking processes did not induce cytotoxicity. Highlights: • 3D scaffolds of Mg-carbonate–apatite and anionic-collagen were produced. • The biomimetic approach and the cross-linking with 0.25% GA solution were employed. • The scaffolds showed open-porous structure and apatite crystals on collagen fibrils. • The cross-linked scaffolds exhibited integrity when immersed in culture medium. • SaOs2 cells adhered and proliferated on the cross-linked scaffolds confirming no cytotoxicity.

  1. Adsorption of CO₂, CH₄, and N₂ on ordered mesoporous carbon: approach for greenhouse gases capture and biogas upgrading.

    Science.gov (United States)

    Yuan, Bin; Wu, Xiaofei; Chen, Yingxi; Huang, Jianhan; Luo, Hongmei; Deng, Shuguang

    2013-05-21

    Separation of CO₂ and N₂ from CH₄ is significantly important in natural gas upgrading, and capture/removal of CO₂, CH₄ from air (N₂) is essential to greenhouse gas emission control. Adsorption equilibrium and kinetics of CO₂, CH₄, and N₂ on an ordered mesoporous carbon (OMC) sample were systematically investigated to evaluate its capability in the above two applications. The OMC was synthesized and characterized with TEM, TGA, small-angle XRD, and nitrogen adsorption/desorption measurements. Pure component adsorption isotherms of CO₂, CH₄, and N₂ were measured at 278, 298, and 318 K and pressures up to 100 kPa, and correlated with the Langmuir model. These data were used to estimate the separation selectivities for CO₂/CH₄, CH₄/N₂, and CO₂/N₂ binary mixtures at different compositions and pressures according to the ideal adsorbed solution theory (IAST) model. At 278 K and 100 kPa, the predicted selectivities for equimolar CO₂/CH₄, CH4/N₂, and CO₂/N₂ are 3.4, 3.7, and 12.8, respectively; and the adsorption capacities for CH₄ and CO₂ are 1.3 and 3.0 mmol/g, respectively. This is the first report of a versatile mesoporous material that displays both high selectivities and large adsorption capacities for separating CO₂/CH₄, CH₄/N₂, and CO₂/N₂ mixtures.

  2. Evaluation of Nanomaterial Approaches to Damping in Epoxy Resin and Carbon Fiber/Epoxy Composite Structures by Dynamic Mechanical Analysis

    Science.gov (United States)

    Miller, G.; Heimann, Paula J.; Scheiman, Daniel A.; Duffy, Kirsten P.; Johnston, J. Chris; Roberts, Gary D.

    2013-01-01

    Vibration mitigation in composite structures has been demonstrated through widely varying methods which include both active and passive damping. Recently, nanomaterials have been investigated as a viable approach to composite vibration damping due to the large surface available to generate energy dissipation through friction. This work evaluates the influence of dispersed nanoparticles on the damping ratio of an epoxy matrix. Limited benefit was observed through dispersion methods, however nanoparticle application as a coating resulting in up to a three-fold increase in damping.

  3. Low carbon society scenario analysis of transport sector of an emerging economy—The AIM/Enduse modelling approach

    International Nuclear Information System (INIS)

    The transport sector of a country is the backbone driving the economy forward. Thailand’s land transport sector is modelled using the AIM/Enduse, which is a recursive dynamic optimization model, based on bottom-up modelling principle. The travel demand is divided into two major categories which are passenger travel and freight travel. The objective of this paper is to analyse the mitigation possible through low carbon society (LCS) measures and emission tax (ET). Two scenario clusters are devised along with the BAU case. The LCS scenario cluster has three designed scenarios which are LCS-L, LCS-M and LCS-H. The emission tax (ET) cluster has four scenarios, where the taxes of 50, 100, 200 and 500 USD/t-CO2 are implemented. Along with this the marginal abatement costs (MAC) of the counter-measures (CMs) and the co-benefits in terms of energy security, productivity and air pollutant mitigation are also assessed. Results show that LCS scenarios are possible of mitigating up to 1230 Mt-CO2 cumulatively, from 2010 to 2050. In terms of MACs, new vehicles play a pivotal role, along with hybrid vehicles. The Average Abatement Cost (AAC) assessment shows that the AAC of LCS-H scenario is in the order of 100 USD/t-CO2. All the LCS and ET scenarios show an enhancement in energy security and also a threefold increase in productivity. There is distinct mitigation in terms of air pollutants from the transport sector as well. -- Highlights: •Thailand transport sector has been modelled using AIM/Enduse model. •Potential cumulative mitigation of CO2 during 2010–2050 is approximately 30% when compared the BAU scenario. •Abatement cost curves show that various counter measures are practical in the transport sector. •Energy security is enhanced due to CO2 mitigation in the LCS scenario

  4. A lipidomic approach to understanding free fatty acid lipogenesis derived from dissolved inorganic carbon within cnidarian-dinoflagellate symbiosis.

    Directory of Open Access Journals (Sweden)

    Simon R Dunn

    Full Text Available The cnidarian-dinoflagellate symbiosis is arguably one of the most important within the marine environment in that it is integral to the formation of coral reefs. However, the regulatory processes that perpetuate this symbiosis remain unresolved. It is essential to understand these processes, if we are to elucidate the mechanisms that support growth and resource accumulation by coral host, and conversely, recently observed reduction and/or mortality of corals in response to rapid environmental change. This study specifically focused on one area of metabolic activity within the symbiosis, that of free fatty acid synthesis within both the dinoflagellate symbionts and cnidarian host. The main model system used was Aiptasia pulchella and Symbiodinium sp. in combination with aposymbiotic A. pulchella, the symbiotic coral Acropora millepora system and dinoflagellate culture. Fatty acids (FAs were selected because of their multiple essential roles inclusive of energy storage (resource accumulation, membrane structure fluidity and cell signaling. The study addressed free FA lipogenesis by using a new method of enriched stable isotopic ((13C incorporation from dissolved inorganic carbon (DI(13C combined with HPLC-MS. FAs derived from DI(13C aligned with a mixture of known lipogenesis pathways with the addition of some unusual FAs. After 120 hr, (13C-enriched FA synthesis rates were attributed to only a complex integration of both n-3 and n-6 lipogenesis pathways within the dinoflagellate symbionts. Furthermore, there was no detectible evidence of symbiont derived enriched isotope fatty acids, catabolized (13C derivatives or DI(13C being directly utilized, in host late n-6 pathway long-chain FA lipogenesis. These findings do not align with a popular mutualistic translocation model with respect to the use of translocated symbiont photoassimilates in host long-chain FA lipogenesis, which has important connotations for linking nutrient sources with

  5. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-06-01

    The application of cyclic CO{sub 2}, often referred to as the CO{sub 2} Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO{sub 2} H-n-P process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in the capital intensive miscible projects. Texaco Exploration and Production Inc. and the US Department of Energy have teamed up in an attempt to develop the CO{sub 2} Huff-n-Puff process in the Grayburg and San Andres formations, a light oil, shallow shelf carbonate reservoir that exists throughout the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. The selected site for this demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. The goals of the project are the development of guidelines for cost-effective selection of candidate reservoirs and wells, along with estimating recovery potential. This project has two defined budget periods. The first budget period primarily involves tasks associated with reservoir analysis and characterization, characterizing existing producibility problems, and reservoir simulation of the proposed technology. The final budget period covers the actual field demonstration of the proposed technology. Technology transfer spans the entire course of the project. This report covers the concluding tasks performed under the second budget period.

  6. Influence of soil sampling approaches in the evaluation of soil organic carbon stocks under different land uses in a Mediterranean area

    Science.gov (United States)

    Francaviglia, Rosa; Doro, Luca; Ledda, Luigi; Parras-Alcántara, Luis; Lozano-García, Beatriz

    2016-04-01

    Different approaches of soil sampling can provide significantly different estimates of soil organic carbon stocks (SOCs) (Parras-Alcántara et al., 2015a). Many studies have focused on SOC distribution only in the biologically active layers of topsoil, the IPCC carbon accounting method estimates the change in SOC storage for the top 30 cm of a soil profile, and indeed limited data are available for SOCs below this depth. Moreover, SOC estimates are more uncertain in areas with heterogeneous land uses and pedoclimatic conditions such as Mediterranean environments, which are more prone to land degradation due to SOC degradation and depletion and erosive processes (Muñoz-Rojas et al., 2015). Anyhow, the open question is whether soil should be sampled following the pedogenetic horizons with soil entire soil approach (ESP), or along fixed depth increments using the soil control section method (SCS) (Parras-Alcántara et al., 2015b). In addition, SOCs are often not adjusted for the soil volume occupied by coarse fragments as recommended by the IPCC Good Practice Guidance for LULUCF (IPCC, 2003) accordingly to the equation: SOCs = SOC (g kg‑1) × bulk density (Mg m‑3) × depth (m) × (1 - coarse fragment) × 10. The work deals with the comparison of SOCs using the ESP and SCS approaches, applied to a study area of northeastern Sardinia (Italy) under typical agro-silvo-pastoral systems (Francaviglia et al., 2014). The area lies within a hilly basin where elevation is in the range 275-340 m a.s.l., and slope ranges from 2-6% to 16-30%. The local climate is warm temperate with dry and hot summers, mean annual rainfall is 623 mm (range 367-811mm) and mean annual temperature is 15.0° C (13.8-16.4° C). The area has the same soil type (Haplic Endoleptic Cambisols, Dystric) according to IUSS Working Group WRB (2006), and the following land uses with different levels of cropping intensification were compared: Tilled vineyards (Tv), No-tilled grassed vineyards (Ntgv), Hay

  7. Influence of soil sampling approaches in the evaluation of soil organic carbon stocks under different land uses in a Mediterranean area

    Science.gov (United States)

    Francaviglia, Rosa; Doro, Luca; Ledda, Luigi; Parras-Alcántara, Luis; Lozano-García, Beatriz

    2016-04-01

    Different approaches of soil sampling can provide significantly different estimates of soil organic carbon stocks (SOCs) (Parras-Alcántara et al., 2015a). Many studies have focused on SOC distribution only in the biologically active layers of topsoil, the IPCC carbon accounting method estimates the change in SOC storage for the top 30 cm of a soil profile, and indeed limited data are available for SOCs below this depth. Moreover, SOC estimates are more uncertain in areas with heterogeneous land uses and pedoclimatic conditions such as Mediterranean environments, which are more prone to land degradation due to SOC degradation and depletion and erosive processes (Muñoz-Rojas et al., 2015). Anyhow, the open question is whether soil should be sampled following the pedogenetic horizons with soil entire soil approach (ESP), or along fixed depth increments using the soil control section method (SCS) (Parras-Alcántara et al., 2015b). In addition, SOCs are often not adjusted for the soil volume occupied by coarse fragments as recommended by the IPCC Good Practice Guidance for LULUCF (IPCC, 2003) accordingly to the equation: SOCs = SOC (g kg-1) × bulk density (Mg m-3) × depth (m) × (1 - coarse fragment) × 10. The work deals with the comparison of SOCs using the ESP and SCS approaches, applied to a study area of northeastern Sardinia (Italy) under typical agro-silvo-pastoral systems (Francaviglia et al., 2014). The area lies within a hilly basin where elevation is in the range 275-340 m a.s.l., and slope ranges from 2-6% to 16-30%. The local climate is warm temperate with dry and hot summers, mean annual rainfall is 623 mm (range 367-811mm) and mean annual temperature is 15.0° C (13.8-16.4° C). The area has the same soil type (Haplic Endoleptic Cambisols, Dystric) according to IUSS Working Group WRB (2006), and the following land uses with different levels of cropping intensification were compared: Tilled vineyards (Tv), No-tilled grassed vineyards (Ntgv), Hay crop

  8. An integrated approach to modeling changes in land use, land cover, and disturbance and their impact on ecosystem carbon dynamics: a case study in the Sierra Nevada Mountains of California

    Directory of Open Access Journals (Sweden)

    Benjamin M. Sleeter

    2015-06-01

    Full Text Available Increased land-use intensity (e.g. clearing of forests for cultivation, urbanization, often results in the loss of ecosystem carbon storage, while changes in productivity resulting from climate change may either help offset or exacerbate losses. However, there are large uncertainties in how land and climate systems will evolve and interact to shape future ecosystem carbon dynamics. To address this we developed the Land Use and Carbon Scenario Simulator (LUCAS to track changes in land use, land cover, land management, and disturbance, and their impact on ecosystem carbon storage and flux within a scenario-based framework. We have combined a state-and-transition simulation model (STSM of land change with a stock and flow model of carbon dynamics. Land-change projections downscaled from the Intergovernmental Panel on Climate Change’s (IPCC Special Report on Emission Scenarios (SRES were used to drive changes within the STSM, while the Integrated Biosphere Simulator (IBIS ecosystem model was used to derive input parameters for the carbon stock and flow model. The model was applied to the Sierra Nevada Mountains ecoregion in California, USA, a region prone to large wildfires and a forestry sector projected to intensify over the next century. Three scenario simulations were conducted, including a calibration scenario, a climate-change scenario, and an integrated climate- and land-change scenario. Based on results from the calibration scenario, the LUCAS age-structured carbon accounting model was able to accurately reproduce results obtained from the process-based biogeochemical model. Under the climate-only scenario, the ecoregion was projected to be a reliable net sink of carbon, however, when land use and disturbance were introduced, the ecoregion switched to become a net source. This research demonstrates how an integrated approach to carbon accounting can be used to evaluate various drivers of ecosystem carbon change in a robust, yet transparent

  9. An environmental tracers approach to characterize groundwater recharge within a carbonate coastal aquifer (Corse-du-Sud, France)

    Science.gov (United States)

    Garel, Emilie; Huneau, Frederic; Khoumeri, Beatrice; Travi, Yves

    2013-04-01

    Bonifacio is a coastal city, highly touristic, located in the southest part of Corsica Island. One million people visit the city in July and August, whereas 3000 inhabitants live throughout the year. Bonifacio lies on a small limestone plateau with a potential aquifer poorly understood. Actually there is a strong need to characterize the hydrogeological behavior for the reason that the economic development of the region is highly dependent of the groundwater supply potential. The Miocene sedimentary basin of Bonifacio has an area of 25 km2 with a depth up to 250 m in the center. It is based and surrounded by a Hercynian granitic substratum. The basin is open to the Mediterranean Sea on its south and east sides. The formation is calcareous-sandstone and is divided in 3 sedimentary units. The upper unit is highly calcareous and sandstone with a pseudo-karstic morphology, the intermediary unit is more silty-sandstone than the last but less than the unit from below. To establish a conceptual model of the groundwater flows of the Bonifacio aquifer, a hydrochemical (major ions, δ18O, δ2H, 3H) and hydrodynamic investigation was carried out on 12 wells, 1 spring and 1 river since May 2011. Vertical recharge is dominant in the centre of the aquifer where unsaturated zone is thicker, while on the aquifer boundaries with the granitic area, lateral flow was significant. Environmental tracers approach had clearly showed the important role of the boundaries conditions for the groundwater flow behavior of the aquifer of Bonifacio and the necessity of an investigation larger than the aquifer itself due to its limited spatial extension.

  10. Eco-hydrologic Modeling of Rangelands: Evaluating a New Carbon Allocation Approach and Simulating Ecosystem Response to Changing Climate and Management Conditions

    Science.gov (United States)

    Reyes, J. J.; Tague, C.; Choate, J. S.; Adam, J. C.

    2014-12-01

    More than one-third of the United States' land cover is comprised of rangelands, which support both forage production and livestock grazing. For grasses in both semi-arid and humid environments, small changes in precipitation and temperature, as well as grazing, can have disproportionately larger impacts on ecosystem processes. For example, these areas may experience large response pulses under highly variable precipitation and other potential future changes. The ultimate goal of this study is to provide information on the interactions between management activities, climate and ecosystem processes to inform sustainable rangeland management. The specific objectives of this paper are to (1) evaluate a new carbon allocation strategy for grasses and (2) test the sensitivity of this improved strategy to changes in climate and grazing strategies. The Regional Hydro-ecologic Simulation System (RHESSys) is a process-based, watershed-scale model that simulates hydrology and biogeochemical cycling with dynamic soil and vegetation modules. We developed a new carbon allocation algorithm for partitioning net primary productivity (NPP) between roots and leaves for grasses. The 'hybrid' approach represents a balance between preferential partitioning due to environmental conditions and age-related growth. We evaluated this new allocation scheme at the point-scale at a variety of rangeland sites in the U.S. using observed biomass measurements and against existing allocation schemes used in RHESSys. Additionally, changes in the magnitude, frequency, and intensity of precipitation and temperature were used to assess ecosystem responses using our new allocation scheme. We found that changes in biomass and NPP were generally more sensitive to changes in precipitation than changes in temperature. At more arid sites, larger percent reductions in historic baseline precipitation affected biomass and NPP more negatively. We incorporated grazing impacts through biomass removal. We found that

  11. Losses of soil organic carbon by converting tropical forest to plantations: Assessment of erosion and decomposition by new δ13C approach

    Science.gov (United States)

    Guillaume, Thomas; Muhammad, Damris; Kuzyakov, Yakov

    2015-04-01

    Indonesia lost more tropical forest than all of Brazil in 2012, mainly driven by the rubber, oil palm and timber industries. Nonetheless, the effects of converting forest to oil palm and rubber plantations on soil organic carbon (SOC) stocks remain unclear. We analyzed SOC losses after lowland rainforest conversion to oil palm, intensive rubber and extensive rubber plantations in Jambi province on Sumatra Island. We developed and applied a new δ13C based approach to assess and separate two processes: 1) erosion and 2) decomposition. Carbon contents in the Ah horizon under oil palm and rubber plantations were strongly reduced: up to 70% and 62%, respectively. The decrease was lower under extensive rubber plantations (41%). The C content in the subsoil was similar in the forest and the plantations. We therefore assumed that a shift to higher δ13C values in the subsoil of the plantations corresponds to the losses of the upper soil layer by erosion. Erosion was estimated by comparing the δ13C profiles in the undisturbed soils under forest with the disturbed soils under plantations. The estimated erosion was the strongest in oil palm (35±8 cm) and rubber (33±10 cm) plantations. The 13C enrichment of SOC used as a proxy of its turnover indicates a decrease of SOC decomposition rate in the Ah horizon under oil palm plantations after forest conversion. SOC availability, measured by microbial respiration rate and Fourier Transformed Infrared Spectroscopy, was lower under oil palm plantations. Despite similar trends in C losses and erosion in intensive plantations, our results indicate that microorganisms in oil palm plantations mineralized mainly the old C stabilized prior to conversion, whereas microorganisms under rubber plantations mineralized the fresh C from the litter, leaving the old C pool mainly untouched. Based on the lack of C input from litter, we expect further losses of SOC under oil palm plantations, which therefore are a less sustainable land

  12. Spatial assessment of soil organic carbon and physicochemical properties in a horticultural orchard at arid zone of India using geostatistical approaches.

    Science.gov (United States)

    Singh, Akath; Santra, Priyabrata; Kumar, Mahesh; Panwar, Navraten; Meghwal, P R

    2016-09-01

    Soil organic carbon (SOC) is a major indicator of long-term sustenance of agricultural production system. Apart from sustaining productivity, SOC plays a crucial role in context of climate change. Keeping in mind these potentials, spatial variation of SOC contents of a fruit orchard comprising several arid fruit plantations located at arid region of India is assessed in this study through geostatistical approaches. For this purpose, surface and subsurface soil samples from 175 locations from a fruit orchard spreading over 14.33 ha area were collected along with geographical coordinates. SOC content and soil physicochemical properties of collected soil samples were determined followed by geostatistical analysis for mapping purposes. Average SOC stock density of the orchard was 14.48 Mg ha(-1) for 0- to 30-cm soil layer ranging from 9.01 Mg ha(-1) in Carissa carandas to 19.52 Mg ha(-1) in Prosopis cineraria block. Range of spatial variation of SOC content was found about 100 m, while two other soil physicochemical properties, e.g., pH and electrical conductivity (EC) also showed similar spatial trend. This indicated that minimum sampling distance for future SOC mapping programme may be kept lower than 100 m for better accuracy. Ordinary kriging technique satisfactorily predicted SOC contents (in percent) at unsampled locations with root-mean-squared residual (RMSR) of 0.35-0.37. Co-kriging approach was found slightly superior (RMSR = 0.26-0.28) than ordinary kriging for spatial prediction of SOC contents because of significant correlations of SOC contents with pH and EC. Uncertainty of SOC estimation was also presented in terms of 90 % confidence interval. Spatial estimates of SOC stock through ordinary kriging or co-kriging approach were also found with low uncertainty of estimation than non-spatial estimates, e.g., arithmetic averaging approach. Among different fruit block plantations of the orchard, the block with Prosopis cineraria ('khejri') has

  13. Improved recovery demonstration for Williston Basin carbonates. Annual report, June 10, 1995--June 9, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Carrell, L.A.; Sippel, M.A.

    1996-09-01

    The purpose of this project is to demonstrate targeted infill and extension drilling opportunities, better determinations of oil-in-place, methods for improved completion efficiency and the suitability of waterflooding in Red River and Ratcliffe shallow-shelf carbonate reservoirs in the Williston Basin, Montana, North Dakota and South Dakota. Improved reservoir characterization utilizing three-dimensional and multi-component seismic are being investigated for identification of structural and stratigraphic reservoir compartments. These seismic characterization tools are integrated with geological and engineering studies. Improved completion efficiency is being tested with extended-reach jetting lance and other ultra-short-radius lateral technologies. Improved completion efficiency, additional wells at closer spacing and better estimates of oil in place will result in additional oil recovery by primary and enhanced recovery processes.

  14. Combined deep sampling and mass-based approaches to assess soil carbon and nitrogen losses due to land-use changes in karst area of southwestern China

    Science.gov (United States)

    Hu, Yecui; Du, Zhangliu; Wang, Qibing; Li, Guichun

    2016-07-01

    The conversion of natural vegetation to human-managed ecosystems, especially the agricultural systems, may decrease soil organic carbon (SOC) and total nitrogen (TN) stocks. The objective of present study was to assess SOC and TN stocks losses by combining deep sampling with mass-based calculations upon land-use changes in a typical karst area of southwestern China. We quantified the changes from native forest to grassland, secondary shrub, eucalyptus plantation, sugarcane and corn fields (both defined as croplands), on the SOC and TN stocks down to 100 cm depth using fixed-depth (FD) and equivalent soil mass (ESM) approaches. The results showed that converting forest to cropland and other types significantly led to SOC and TN losses, but the extent depended on both sampling depths and calculation methods selected (i.e., FD or ESM). On average, the shifting from native forest to cropland led to SOC losses by 19.1, 25.1, 30.6, 36.8 and 37.9 % for the soil depths of 0-10, 0-20, 0-40, 0-60 and 0-100 cm, respectively, which highlighted that shallow sampling underestimated SOC losses. Moreover, the FD method underestimated SOC and TN losses for the upper 40 cm layer, but overestimated the losses in the deeper layers. We suggest that the ESM together with deep sampling should be encouraged to detect the differences in SOC stocks. In conclusion, the conversion of forest to managed systems, in particular croplands significantly decreased in SOC and TN stocks, although the effect magnitude to some extent depended on sampling depth and calculation approach selected.

  15. Segmentation and additive approach: A reliable technique to study noncovalent interactions of large molecules at the surface of single-wall carbon nanotubes.

    Science.gov (United States)

    Torres, Ana M; Scheiner, Steve; Roy, Ajit K; Garay-Tapia, Andrés M; Bustamante, John; Kar, Tapas

    2016-08-01

    This investigation explores a new protocol, named Segmentation and Additive approach (SAA), to study exohedral noncovalent functionalization of single-walled carbon nanotubes with large molecules, such as polymers and biomolecules, by segmenting the entire system into smaller units to reduce computational cost. A key criterion of the segmentation process is the preservation of the molecular structure responsible for stabilization of the entire system in smaller segments. Noncovalent interaction of linoleic acid (LA, C18 H32 O2 ), a fatty acid, at the surface of a (10,0) zigzag nanotube is considered for test purposes. Three smaller segmented models have been created from the full (10,0)-LA system and interaction energies were calculated for these models and compared with the full system at different levels of theory, namely ωB97XD, LDA. The success of this SAA is confirmed as the sum of the interaction energies is in very good agreement with the total interaction energy. Besides reducing computational cost, another merit of SAA is an estimation of the contributions from different sections of the large system to the total interaction energy which can be studied in-depth using a higher level of theory to estimate several properties of each segment. On the negative side, bulk properties, such as HOMO-LUMO (highest occupied molecular orbital - lowest occupied molecular orbital) gap, of the entire system cannot be estimated by adding results from segment models. © 2016 Wiley Periodicals, Inc. PMID:27241227

  16. A new kinetic-mechanistic approach to elucidate electrooxidation of doxorubicin hydrochloride in unprocessed human fluids using magnetic graphene based nanocomposite modified glassy carbon electrode.

    Science.gov (United States)

    Soleymani, Jafar; Hasanzadeh, Mohammad; Shadjou, Nasrin; Khoubnasab Jafari, Maryam; Gharamaleki, Jalil Vaez; Yadollahi, Mehdi; Jouyban, Abolghasem

    2016-04-01

    A novel magnetic nanocomposite was synthesized in one step using polymerization of magnetic graph oxide grafted with chlorosulfonic acid (Fe3O4-GO-SO3H) in the presence of polystyrene. The prepared magnetic nanocomposite was characterized using transmission electron microscopy (TEM), dynamic differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), (Thermo-gravimetric/differential thermal analysis (DTA)), Fourier transform infrared (FTIR), and UV-Vis techniques. Magnetic nanocomposite was casted on the surface of the glassy carbon electrode (PS/Fe3O4-GO-SO3H/GCE) and used for the detection and determination of doxorubicin hydrochloride (DOX) in human biological fluids. The cyclic voltammograms (CVs) of the modified electrode in aqueous solution displayed a pair of well-defined, stable and irreversible reductive/oxidation redox systems. CV study indicated that the oxidation process is irreversible and adsorption controlled. In addition, CV results indicated that DOX is oxidized via two electrons and three protons which is an unusual approach for the oxidation of DOX. A sensitive and time-saving procedure was developed for the analysis of DOX in plasma, cerebrospinal fluid, and urine with detection limit of 4.9 nM, 14 nM and 4.3 nM, respectively. PMID:26838892

  17. Preparation of High-Efficiency Cytochrome c-Imprinted Polymer on the Surface of Magnetic Carbon Nanotubes by Epitope Approach via Metal Chelation and Six-Membered Ring.

    Science.gov (United States)

    Qin, Ya-Ping; Li, Dong-Yan; He, Xi-Wen; Li, Wen-You; Zhang, Yu-Kui

    2016-04-27

    A novel epitope molecularly imprinted polymer on the surface of magnetic carbon nanotubes (MCNTs@EMIP) was successfully fabricated to specifically recognize target protein cytochrome c (Cyt C) with high performance. The peptides sequences corresponding to the surface-exposed C-terminus domains of Cyt C was selected as epitope template molecule, and commercially available zinc acrylate and ethylene glycol dimethacrylate (EGDMA) were employed as functional monomer and cross-linker, respectively, to synthesize MIP via free radical polymerization. The epitope was immobilized via metal chelation and six-membered ring formed between the functional monomer and the hydroxyl and amino groups of the epitope. The resulting MCNTs@EMIP exhibited specific recognition ability toward target Cyt C including more satisfactory imprinting factor (about 11.7) than that of other reported imprinting methods. In addition, the MCNTs@EMIP demonstrated a high adsorption amount (about 780.0 mg g(-1)) and excellent selectivity. Besides, the magnetic property of the support material made the processes easy and highly efficient by assistance of an external magnetic field. High-performance liquid chromatography analysis of Cyt C in bovine blood real sample and protein mixture indicated that the specificity was not affected by other competitive proteins, which forcefully stated that the MCNTs@EMIP had potential to be applied in bioseparation area. In brief, this study provided a new protocol to detect target protein in complex sample via epitope imprinting approach and surface imprinting strategy. PMID:27049646

  18. A new approach to understand methylmercury (CH3Hg) sources and transformation pathways: Compound-specific carbon stable isotope analysis by GC-C-IRMS

    Science.gov (United States)

    Baya, P. A.; Point, D.; Amouroux, D. P.; Lebreton, B.; Guillou, G.

    2015-12-01

    Methylmercury (CH3Hg) is a potent neurotoxin which is readily assimilated by organisms and bio-accumulates in aquatic food webs. In humans, consumption of CH3Hg contaminated marine fish is the major route of mercury exposure. However, our understanding of CH3Hg transformation pathways is still incomplete. To close this knowledge gap, we propose to explore the stable carbon isotopic composition (δ13C) of the methyl group of CH3Hg for a better understanding of its sources and transformation mechanisms. The method developed for the determination of the δ13C value of CH3Hg in biological samples involves (i) CH3Hg selective extraction, (ii) derivatization, and (iii) separation by gas chromatography (GC) prior to analysis by combustion isotope ratio mass spectrometry (C-IRMS). We present the figures of merit of this novel method and the first δ13C signatures for certified materials (ERM-CE464, BCR414) and biological samples at different marine trophic levels (i.e., tuna fish, zooplankton). The implications of this new approach to trace the pathways associated with Hg methylation and the mechanisms involved will be discussed.

  19. Definitions and Carbon Stocks Accounting Approaches of Harvested Wood Products in Climate Change Negotiation%气候变化谈判中木质林产品的相关概念及其碳储量核算

    Institute of Scientific and Technical Information of China (English)

    白彦锋; 姜春前; 张守攻; 雷静品

    2011-01-01

    Under the United Nations framework convention on climate change ( UNFCCC ), all parties are required to report their greenhouse gas (GHG) emissions and removals. The carbon stocks of harvested wood products (HWP) are also a part of greenhouse gases (GHG) inventory. Forest harvest and wood product consumption play an important role in the carbon balance between forests and atmosphere. Consumption of wood products emits carbon, especially they are used in the landfill. However, the definitions and accounting approaches of HWP are still uncertainty. The implication of approaches applying in different countries is unclear. To impulse the ongoing international negotiation, this paper discussed the definitions and accounting approaches within the documents of UNFCCC and intergovernmental panel on climate change (IPCC) report, and also expanded the implication of HWP from a new position, which gave prominence to equity. In addition, this paper firstly put forward the new definition of carbon quality.%@@ 森林在维持全球碳平衡中发挥着重要的作用.采伐后木质林产品(harvested wood products,HWP)以下简称木质林产品.木质林产品是森林资源利用的自然延伸.

  20. Elucidation of rice rhizosphere metagenome in relation to methane and nitrogen metabolism under elevated carbon dioxide and temperature using whole genome metagenomic approach.

    Science.gov (United States)

    Bhattacharyya, P; Roy, K S; Das, M; Ray, S; Balachandar, D; Karthikeyan, S; Nayak, A K; Mohapatra, T

    2016-01-15

    Carbon (C) and nitrogen (N) mineralization is one of the key processes of biogeochemical cycling in terrestrial ecosystem in general and rice ecology in particular. Rice rhizosphere is a rich niche of microbial diversity influenced by change in atmospheric temperature and concentration of carbon dioxide (CO2). Structural changes in microbial communities in rhizosphere influence the nutrient cycling. In the present study, the bacterial diversity and population dynamics were studied under ambient CO2 (a-CO2) and elevated CO2+temperature (e-CO2T) in lowland rice rhizosphere using whole genome metagenomic approach. The whole genome metagenomic sequence data of lowland rice exhibited the dominance of bacterial communities including Proteobacteria, Firmicutes, Acidobacteria, Actinobacteria and Planctomycetes. Interestingly, four genera related to methane production namely, Methanobacterium, Methanosphaera, Methanothermus and Methanothermococcus were absent in a-CO2 but noticed under e-CO2T. The acetoclastic pathway was found as the predominant pathway for methanogenesis, whereas, the serine pathway was found as the principal metabolic pathway for CH4 oxidation in lowland rice. The abundances of reads of enzymes in the acetoclastic methanogenesis pathway and serine pathways of methanotrophy were much higher in e-CO2T (328 and 182, respectively) as compared with a-CO2 (118 and 98, respectively). Rice rhizosphere showed higher structural diversities and functional activities in relation to N metabolism involving nitrogen fixation, assimilatory and dissimilatory nitrate reduction and denitrification under e-CO2T than that of a-CO2. Among the three pathways of N metabolism, dissimilarity pathways were predominant in lowland rice rhizosphere and more so under e-CO2T. Consequently, under e-CO2T, CH4 emission, microbial biomass nitrogen (MBN) and dehydrogenase activities were 45%, 20% and 35% higher than a-CO2, respectively. Holistically, a high bacterial diversity and

  1. Elucidation of rice rhizosphere metagenome in relation to methane and nitrogen metabolism under elevated carbon dioxide and temperature using whole genome metagenomic approach.

    Science.gov (United States)

    Bhattacharyya, P; Roy, K S; Das, M; Ray, S; Balachandar, D; Karthikeyan, S; Nayak, A K; Mohapatra, T

    2016-01-15

    Carbon (C) and nitrogen (N) mineralization is one of the key processes of biogeochemical cycling in terrestrial ecosystem in general and rice ecology in particular. Rice rhizosphere is a rich niche of microbial diversity influenced by change in atmospheric temperature and concentration of carbon dioxide (CO2). Structural changes in microbial communities in rhizosphere influence the nutrient cycling. In the present study, the bacterial diversity and population dynamics were studied under ambient CO2 (a-CO2) and elevated CO2+temperature (e-CO2T) in lowland rice rhizosphere using whole genome metagenomic approach. The whole genome metagenomic sequence data of lowland rice exhibited the dominance of bacterial communities including Proteobacteria, Firmicutes, Acidobacteria, Actinobacteria and Planctomycetes. Interestingly, four genera related to methane production namely, Methanobacterium, Methanosphaera, Methanothermus and Methanothermococcus were absent in a-CO2 but noticed under e-CO2T. The acetoclastic pathway was found as the predominant pathway for methanogenesis, whereas, the serine pathway was found as the principal metabolic pathway for CH4 oxidation in lowland rice. The abundances of reads of enzymes in the acetoclastic methanogenesis pathway and serine pathways of methanotrophy were much higher in e-CO2T (328 and 182, respectively) as compared with a-CO2 (118 and 98, respectively). Rice rhizosphere showed higher structural diversities and functional activities in relation to N metabolism involving nitrogen fixation, assimilatory and dissimilatory nitrate reduction and denitrification under e-CO2T than that of a-CO2. Among the three pathways of N metabolism, dissimilarity pathways were predominant in lowland rice rhizosphere and more so under e-CO2T. Consequently, under e-CO2T, CH4 emission, microbial biomass nitrogen (MBN) and dehydrogenase activities were 45%, 20% and 35% higher than a-CO2, respectively. Holistically, a high bacterial diversity and

  2. A cheap and non-destructive approach to increase coverage/loading of hydrophilic hydroxide on hydrophobic carbon for lightweight and high-performance supercapacitors

    OpenAIRE

    Liuyang Zhang; Hao Gong

    2015-01-01

    Carbon-based substrates offer unprecedented advantages in lightweight supercapacitors. However, it is still challenging to achieve high coverage or loading. Different from the traditional belief that a lack of defects or functional groups is the cause of poor growth on carbon-based substrates, we reckon that the major cause is the discrepancy between the hydrophilic nature of the metal oxide/hydroxide and the hydrophobic nature of carbon. To solve this incompatibility, we introduced ethanol i...

  3. An integrated approach for determination of pore-type distribution in carbonate-siliciclastic Asmari Reservoir, Cheshmeh-Khosh Oilfield, SW Iran

    Science.gov (United States)

    Gharechelou, Sajjad; Amini, Abdolhossein; Kadkhodaie-Ilkhchi, Ali; Moradi, Babak

    2015-10-01

    This paper presents an integrated pore type study at microscopic (core data), mesoscopic (well logs) and megascopic scales (3D seismic data) in the mixed carbonate-siliciclastic Asmari Reservoir of the Cheshmeh-Khosh Oilfield, SW Iran. Firstly, pore types are determined in a microscopic scale based on petrographic studies of thin sections. Well logs and nuclear magnetic resonance (NMR) log data are employed for pore type determination based on a velocity deviation log (mesoscopic scale). For each pore type subclass, a suite of physical rock properties including average poroperm values, T2 distribution, capillary pressure, pore size distribution and depositional texture are calculated. For this purpose, the NMR log, mercury injection capillary pressure data and core descriptions are interpreted in an integrated approach. Capillary pressure and pore size distribution in each pore type class are determined by mercury injection capillary pressure tests and synthesis of a continuous capillary pressure log from the NMR log (pseudo Pc curves). For dynamic behavior examination of the reservoir, the pore types are analysed in the framework of hydraulic flow units. Finally, 3D post-stacked seismic data are converted to a cube of pore types based on acoustic impedance inversion and seismic attributes. The methodology of this study is accomplished by using core and log data from three key wells and a 3D post-stack seismic data from the studied field. Lastly, a map of pore type distribution is established to provide a clue on the high and low permeable zones of the field. The presented methodology signifies reservoir anatomy on micro to mega scales.

  4. Soil Carbon Losses after Rainforest Conversion to Oil Palm and Rubber Plantations: Processes and Sensitivity of Soil Fertility Indicators Assessed by a New Approach

    Science.gov (United States)

    Guillaume, T.; Maranguit, D.; Murtilaksono, K.; Kuzyakov, Y.

    2015-12-01

    Tropical forest conversion to agricultural land leads to strong decrease of soil organic matter (SOM). Nonetheless, the magnitude of SOM losses and their impacts on soil fertility in oil palm and rubber plantations remain unclear, despite the large scale extension of such land-use types. We quantified SOM losses, and estimated soil erosion and changes in SOM turnover using SOM δ13C values in forest, oil palm plantations, extensive rubber plantations and rubber monocultures on Sumatra Island (Indonesia). Further, we assessed the response of biological (basal respiration, microbial biomass, acid phosphatase) and chemical fertility indicators (light fraction, DOC, total N, available P) to SOM losses. We used a new approach based on (non-)linear regressions between SOM losses and the indices standardized to natural ecosystem. Carbon contents in the Ah horizon under oil palm and rubber plantations were strongly reduced: up to 70% and 62%, respectively. The decrease was lower under extensive rubber (41%). The estimated erosion was the strongest in oil palm (35±8 cm) and rubber (33±10 cm) plantations. The SOM 13C enrichment used as a proxy of its turnover indicates a decrease of SOM turnover under oil palm after forest conversion. The negative impact of land-use changes on all measured indicators increased in the following sequence: forest > extensive rubber > rubber > oil palm. The basal respiration, microbial biomass and nutrients were comparatively resistant to SOM losses, whereas the light fraction was lost faster than the SOM. The resistance of the microbial activity to SOM losses is an indication that the microbial functions sustain SOM losses. However, responses of basal respiration and microbial biomass to SOM losses were non-linear. Below 2.7 % C content, the relationship was reversed. The basal respiration decreased faster than the SOM, resulting in a stronger drop of microbial activity under oil palm compared to rubber despite small difference in C content

  5. Coupling experimental and field-based approaches to decipher carbon sources in the shell of the great scallop, Pecten maximus (L.)

    Science.gov (United States)

    Marchais, V.; Richard, J.; Jolivet, A.; Flye-Sainte-Marie, J.; Thébault, J.; Jean, F.; Richard, P.; Paulet, Y.-M.; Clavier, J.; Chauvaud, L.

    2015-11-01

    This research investigated how the carbon isotopic composition of food source (δ13Cfood) and dissolved inorganic carbon (δ13CDIC) influences the carbon isotopic composition of Pecten maximus shells (δ13Cshell) under both experimental and natural conditions. The objectives are to better understand the relationship between P. maximus and its environment, and to specifically distinguish conditions under which calcification is influenced by respired CO2 derived from food sources versus conditions in which calcification uses inorganic carbon from seawater. Laboratory experiment investigated carbon incorporation into shell carbonates by maintaining scallops under conditions where the stable carbon isotopic composition of food sources was considerably depleted (-54‰), relative to values observed in the natural environment (-21‰). Laboratory experiment ran for 78 days under three temperature conditions, 15 °C, 21 °C and 25 °C. A survey of the environmental parameters and stable carbon isotopic composition into shell carbonate of natural population of P. maximus was also realized during the same year in the Bay of Brest, France. Data collected from both laboratory experiment and the natural environment confirmed that both δ13CDIC and δ13Cfood influence δ13Cshell values and that organic carbon incorporation (CM) averages about 10% (4.3-6.8% under experimental conditions and 1.9-16.6% in the natural environment). The shift in stable carbon isotopic composition from the uptake of depleted food sources under experimental conditions realized a marked divergence in the predicted equilibrium between calcium carbonate and ambient bicarbonate, relative to the natural environment. This offset was 1.7 ± 0.6‰ for scallops in their natural environment and 2.5 ± 0.5 and 3.2 ± 0.9‰ for scallops under experimental conditions at water temperatures of 15 °C and 21 °C, respectively. The offset of 3‰ for scallops subjected to laboratory experiment could not be explained

  6. Carbon Carbon Composites: An Overview .

    OpenAIRE

    G. Rohini Devi; K. Rama Rao

    1993-01-01

    Carbon carbon composites are a new class of engineering materials that are ceramic in nature but exhibit brittle to pseudoplastic behaviour. Carbon-carbon is a unique all-carbon composite with carbon fibre embeded in carbon matrix and is known as an inverse composite. Due to their excellent thermo-structural properties, carbon-carbon composites are used in specialised application like re-entry nose-tips, leading edges, rocket nozzles, and aircraft brake discs apart from several indust...

  7. Contents and Approaches of Implementing Low-carbon Lifestyle%践行低碳生活的内容与途径探讨

    Institute of Scientific and Technical Information of China (English)

    杨冰梅

    2012-01-01

    The "low-carbon economy"is a new concept which is proposed to response to the global climate changes caused by large consumption of oil and a lot of emissions of carbon dioxide.Developing low-carbon economy is a global revolution which involves the mode of production,lifestyles,attitudes and national interests.And the "low-carbon life"is a simple,frugal and sustainable lifestyle.In order to achieve the goal of "low carbon life",it is important to promote propaganda and establish the guarantee system.However,it is not enough that there are only the advanced technologies supporting the development of "low-carbon economy",it must rely on the implementation of "low-carbon life"to achieve the purpose of emission reduction.%分析了低碳经济的概念及形成背景,探讨了低碳经济与低碳生活的关系,并提出了相应的对策与建议,为推行低碳生活提供参考。

  8. Carbon Carbon Composites: An Overview .

    Directory of Open Access Journals (Sweden)

    G. Rohini Devi

    1993-10-01

    Full Text Available Carbon carbon composites are a new class of engineering materials that are ceramic in nature but exhibit brittle to pseudoplastic behaviour. Carbon-carbon is a unique all-carbon composite with carbon fibre embeded in carbon matrix and is known as an inverse composite. Due to their excellent thermo-structural properties, carbon-carbon composites are used in specialised application like re-entry nose-tips, leading edges, rocket nozzles, and aircraft brake discs apart from several industrial and biomedical applications. The multidirectional carbon-carbon product technology is versatile and offers design flexibility. This paper describes the multidirectional preform and carbon-carbon process technology and research and development activities within the country. Carbon-carbon product experience at DRDL has also been discussed. Development of carbon-carbon brake discs process technology using the liquid impregnation process is described. Further the test results on material characterisation, thermal, mechanical and tribological properties are presented.

  9. The utilization of the microflora indigenous to and present in oil-bearing formations to selectively plug the more porous zones thereby increasing oil recovery during waterflooding. Technical progress report, January 1, 1997--December 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, J.O.

    1998-12-01

    This project is a field demonstration of the ability of in-situ indigenous microorganisms in the North Blowhorn Creek Oil Field to reduce the flow of injection water in the more permeable zones of the reservoir, thereby diverting flow to other areas thus increasing the efficiency of the waterflood. The project is divided into three phases: Planning and Analysis (9 months), Implementation (45 months), and Technology Transfer (12 months). This report covers the fourth year of work on the project. Twenty-two months after the injection of nutrients into the reservoir began, three wells were drilled and cores taken therefrom were analyzed. Oil production volumes and water:oil ratios (WOR) of produced fluids have shown clearly that the MEOR treatment being demonstrated in this project is improving oil recovery. Of the 15 producer wells in the test patterns, seven have responded positively to the injection of microbial nutrients into the reservoir, while all eight of the producer wells only in control patterns have continued their natural decline in oil production, although one well did have some improvement in oil production due to increased water injection into a nearby injector well. In light of these positive findings and with DOE`s approval, the scope of the field demonstration was expanded in July 1997 to include six new injector wells. Of interest has been the performance of two wells in what was formerly a control pattern. Since the injector in this pattern (formerly Control Pattern 2) began receiving nutrients, two of the wells in the pattern have shown improved oil production for the last three months. While it would be premature to definitely characterize these two wells as yielding a positive response, these early results are certainly encouraging.

  10. Fluid Substitution Modeling to Determine Sensitivity of 3D Vertical Seismic Profile Data to Injected CO­2­ at an active Carbon Capture, Utilization and Storage Project, Farnsworth field, TX.

    Science.gov (United States)

    Haar, K. K.; Balch, R. S.

    2015-12-01

    The Southwest Regional Partnership on Carbon Sequestration monitors a CO2 capture, utilization and storage project at Farnsworth field, TX. The reservoir interval is a Morrowan age fluvial sand deposited in an incised valley. The sands are between 10 to 25m thick and located about 2800m below the surface. Primary oil recovery began in 1958 and by the late 1960's secondary recovery through waterflooding was underway. In 2009, Chaparral Energy began tertiary recovery using 100% anthropogenic CO2 sourced from an ethanol and a fertilizer plant. This constitutes carbon sequestration and fulfills the DOE's initiative to determine the best approach to permanent carbon storage. One purpose of the study is to understand CO­2 migration from injection wells. CO2­ plume spatial distribution for this project is analyzed with the use of time-lapse 3D vertical seismic profiles centered on CO2 injection wells. They monitor raypaths traveling in a single direction compared to surface seismic surveys with raypaths traveling in both directions. 3D VSP surveys can image up to 1.5km away from the well of interest, exceeding regulatory requirements for maximum plume extent by a factor of two. To optimize the timing of repeat VSP acquisition, the sensitivity of the 3D VSP surveys to CO2 injection was analyzed to determine at what injection volumes a seismic response to the injected CO­2 will be observable. Static geologic models were generated for pre-CO2 and post-CO2 reservoir states through construction of fine scale seismic based geologic models, which were then history matched via flow simulations. These generated static states of the model, where CO2­ replaces oil and brine in pore spaces, allow for generation of impedance volumes which when convolved with a representative wavelet generate synthetic seismic volumes used in the sensitivity analysis. Funding for the project is provided by DOE's National Energy Technology Laboratory (NETL) under Award No. DE-FC26-05NT42591.

  11. Triplex inducer-directed self-assembly of single-walled carbon nanotubes: a triplex DNA-based approach for controlled manipulation of nanostructures

    OpenAIRE

    Zhao, Chao; Qu, Konggang; Xu, Can; Ren, Jinsong; Qu, Xiaogang

    2011-01-01

    As a promising strategy for artificially control of gene expression, reversible assembly of nanomaterials and DNA nanomachine, DNA triplex formation has received much attention. Carbon nanotubes as gene and drug delivery vector or as ‘building blocks’ in nano/microelectronic devices have been successfully explored. Therefore, studies on triplex DNA-based carbon nanotube hybrid materials are important for development of smart nanomaterials and for gene therapy. In this report, a small molecule...

  12. Underground Coal Gasification with Extended CO2 Utilization - An Economic and Carbon Neutral Approach to Tackle Energy and Fertilizer Supply Shortages in Bangladesh

    OpenAIRE

    Natalie Christine Nakaten; Rafiqul Islam; T. Kempka

    2014-01-01

    UCG facilitates deep-seated coal seam utilization in the Jamalganj deposit (Bangladesh) by producing synthesis gas for electricity and fertilizer production. Based on previous studies which assessed UCG combined with carbon utilization in a urea process, we further investigated excess CO2 utilization by means of enhanced gas recovery (EGR) at the Bahkrabad gas field. Our techno-economic modeling results demonstrate that an economic and carbon neutral UCG operation with urea productio...

  13. Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data

    Science.gov (United States)

    Hayes, Daniel J.; Turner, David P.; Stinson, Graham; McGuire, A. David; Wei, Yaxing; West, Tristram O.; Heath, Linda S.; de Jong, Bernardus; McConkey, Brian G.; Birdsey, Richard A.; Kurz, Werner A.; Jacobson, Andrew R.; Huntzinger, Deborah N.; Pan, Yude; Post, W. Mac; Cook, Robert B.

    2012-01-01

    We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000–2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a -327 ± 252 TgC yr-1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (-248 TgC yr-1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (-297 TgC yr-1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr-1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated to be a small net source (+18 TgC yr-1) due to land use change between 1993 and 2002. We compare these inventory-based estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is -511 TgC yr-1 and -931 TgC yr-1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional -239 TgC yr-1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

  14. A density functional reactivity theory (DFRT) based approach to understand the effect of symmetry of fullerenes on the kinetic, thermodynamic and structural aspects of carbon NanoBuds

    Science.gov (United States)

    Sarmah, Amrit; Roy, Ram Kinkar

    2016-06-01

    In the present study, we have rationalized the effect of variation in the symmetry of relatively smaller fullerene (C32) on the mode of its interaction with semi-conducting Single-Walled Carbon Nanotubes (SWCNTs) in the process of formation of stable hybrid carbon NanoBuds. Thermodynamic and kinetic parameters, along with the charge transfer values associated with the interaction between fullerene and SWCNTs, have been evaluated using an un-conventional and computationally cost-effective method based on density functional reactivity theory (DFRT). In addition to this, conventional DFT based studies are also performed to substantiate the growth of NanoBud structures formed by the interaction between fullerene and SWCNTs. The findings of the present study suggest that the kinetic, thermodynamic and structural aspects of hybrid carbon NanoBuds are significantly influenced by both the symmetry of C32 fullerene and its site of covalent attachment to the SWCNT.

  15. Plumbing carbon nanotubes

    Science.gov (United States)

    Jin, Chuanhong; Suenaga, Kazu; Iijima, Sumio

    2008-01-01

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

  16. ATOMIC-LEVEL MODELING OF CO2 DISPOSAL AS A CARBONATE MINERAL: A SYNERGETIC APPROACH TO OPTIMIZING REACTION PROCESS DESIGN; FINAL

    International Nuclear Information System (INIS)

    Fossil fuels, especially coal, can support the energy demands of the world for centuries to come, if the environmental problems associated with CO(sub 2) emissions can be overcome. Permanent and safe methods for CO(sub 2) capture and disposal/storage need to be developed. Mineralization of stationary-source CO(sub 2) emissions as carbonates can provide such safe capture and long-term sequestration. Mg-rich lamellar hydroxide mineral carbonation is a leading process candidate, which generates the stable naturally occurring mineral magnesite (MgCO(sub 3)) and water. Key to process cost and viability are the carbonation reaction rate and its degree of completion. This process, which involves simultaneous dehydroxylation and carbonation is very promising, but far from optimized. In order to optimize the dehydroxylation/carbonation process, an atomic-level understanding of the mechanisms involved is needed. In this investigation Mg(OH)(sub 2) was selected as a model Mg-rich lamellar hydrocide carbonation feedstock material due to its chemical and structural simplicity. Since Mg(OH)(sub 2) dehydroxylation is intimately associated with the carbonation process, its mechanisms are also of direct interest in understanding and optimizing the process. The aim of the current innovative concepts project is to develop a specialized advanced computational methodology to complement the ongoing experimental inquiry of the atomic level processes involved in CO(sub 2) mineral sequestration. The ultimate goal is to integrate the insights provided by detailed predictive simulations with the data obtained from optical microscopy, FESEM, ion beam analysis, SIMS, TGA, Raman, XRD, and C and H elemental analysis. The modeling studies are specifically designed to enhance the synergism with, and complement the analysis of, existing mineral-CO(sub 2) reaction process studies being carried out under DOE UCR Grant DE-FG2698-FT40112. Direct contact between the simulations and the experimental

  17. Microbial diversity in methanogenic hydrocarbon-degrading enrichment cultures isolated from a water-flooded oil reservoir (Dagang oil field, China)

    Science.gov (United States)

    Jiménez, Núria; Cai, Minmin; Straaten, Nontje; Yao, Jun; Richnow, Hans H.; Krüger, Martin

    2015-04-01

    Microbial transformation of oil to methane is one of the main degradation processes taking place in oil reservoirs, and it has important consequences as it negatively affects the quality and economic value of the oil. Nevertheless, methane could constitute a recovery method of carbon from exhausted reservoirs. Previous studies combining geochemical and isotopic analysis with molecular methods showed evidence for in situ methanogenic oil degradation in the Dagang oil field, China (Jiménez et al., 2012). However, the main key microbial players and the underlying mechanisms are still relatively unknown. In order to better characterize these processes and identify the main microorganisms involved, laboratory biodegradation experiments under methanogenic conditions were performed. Microcosms were inoculated with production and injection waters from the reservoir, and oil or 13C-labelled single hydrocarbons (e.g. n-hexadecane or 2-methylnaphthalene) were added as sole substrates. Indigenous microbiota were able to extensively degrade oil within months, depleting most of the n-alkanes in 200 days, and producing methane at a rate of 76 ± 6 µmol day-1 g-1 oil added. They could also produce heavy methane from 13C-labeled 2-methylnaphthalene, suggesting that further methanogenesis may occur from the aromatic and polyaromatic fractions of Dagang reservoir fluids. Microbial communities from oil and 2-methyl-naphthalene enrichment cultures were slightly different. Although, in both cases Deltaproteobacteria, mainly belonging to Syntrophobacterales (e.g. Syntrophobacter, Smithella or Syntrophus) and Clostridia, mostly Clostridiales, were among the most represented taxa, Gammaproteobacteria could be only identified in oil-degrading cultures. The proportion of Chloroflexi, exclusively belonging to Anaerolineales (e.g. Leptolinea, Bellilinea) was considerably higher in 2-methyl-naphthalene degrading cultures. Archaeal communities consisted almost exclusively of representatives of

  18. Integrating Role-Play with Case Study and Carbon Footprint Monitoring: A Transformative Approach to Enhancing Learners' Social Behavior for a More Sustainable Environment

    Science.gov (United States)

    Oliver, Simon

    2016-01-01

    Learners were separated into groups representing the interests of parties that typically negotiate environmental affairs in real world scenarios (conservationists, scientists, politicians, NGOs, stakeholders), and tasked with preparing role-play simulations using a variety of flipped learning techniques. Learners' carbon footprints were monitored…

  19. Recovery of Waterflood Residual Oil Using Alkali, Surfactant and Polymer Slugs in Radial Cores Récupération d'huile résiduelle par injection d'eau améliorée de produits alcalins, de tensio-actifs et de polymères dans des carottes radiales

    Directory of Open Access Journals (Sweden)

    Nasr-El-Din H. A.

    2006-11-01

    Full Text Available An experimental study has been conducted to examine mobilization and recovery of waterflood residual oil in radial cores. Alkali, surfactant, and polymer slugs of various compositions, sizes and sequences were tested. Core flood experiments were conducted with unfired radial Berea sandstone disks at a flow rate of 8 cm3/h. David Lloydminster crude oil (total acid number of 0. 45 mg KOH/g oil was used. The results of the present work showed that the composition and sequence of the injected chemical slug play an important role in mobilization and recovery of residual oil. For slugs lacking either mobility control, or low interfacial tension, no oil bank was formed and tertiary oil recovery was less than 20% Sor. A significant oil bank and tertiary oil recovery up to 70 % Sor were obtained with slugs having mobility control and low interfacial tension. However, maximum oil cut, incre-mental oil recovery and surfactant propagation were found to be functions of the alkali content in the slug. The incremental oil recovery, oil cut and slug injectivity greatly improved as the alkali concentration (sodium carbonate in the combined slug was increased. A slight delay in surfactant breakthrough and a significantly slower rate of surfactant propagation were observed at higher sodium carbonate concentrations. Une étude expérimentale ayant pour but d'examiner la mobilisation et la récupération assistée d'huile résiduelle, à la suite d'un déplacement par l'eau en milieu poreux, a été conduite. Des bouchons de produit alcalin, de surfactant et de polymère, ayant des compositions, grosseurs et séquences d'injection variées, furent essayés. Les déplacements en milieu poreux furent conduits en utilisant des carottes de grès berea (non traités à haute température et un débit de 8,0 cm3/h. Pour ce faire, on utilisa de l'huile de David Lloydminster (ayant un nombre acide de 0,45 mg KOH/g d'huile. Les résultats de ce travail ont démontré que la

  20. Interaction between Fingering and Heterogeneity during Viscous Oil Recovery in Carbonate Rocks (Invited)

    Science.gov (United States)

    Mohanty, K. K.; Doorwar, S.

    2013-12-01

    Due to the fast depleting conventional oil reserves, research in the field of petroleum engineering has shifted focus towards unconventional (viscous and heavy) oils. Many of the viscous oil reserves are in carbonate rocks. Thermal methods in carbonate formations are complicated by mineral dissolution and precipitation. Non-thermal methods should be developed for viscous oils in carbonates. In viscous oil reservoirs, oil recovery due to water flood is low due to viscous fingering. Polymer flood is an attractive process, but the timing of the polymer flood start is an important parameter in the optimization of polymer floods. Vuggy Silurian dolomite cores were saturated with formation brine and reservoir oil (150-200 cp). They were then displaced by either a polymeric solution (secondary polymer flood) or brine followed the polymeric solution (tertiary polymer flood). The amount of brine injection was varied as a parameter. Oil recovery and pressure drop was monitored as a function of the starting point of the polymer flood. To visualize the displacement at the pore-scale, two types of micromodels were prepared: one with isolated heterogeneity and the other with connected heterogeneity. The wettability of the micromodels was either water-wet or oil-wet. The micromodels were saturated with formation brine and oil. A series of water flood and polymer flood was conducted to identify the mechanism of fluid flow. Dolomite corefloods show that a tertiary polymer flood following a secondary water flood recovers a substantial amount of oil unlike what is observed in typical sandstone cores with light oil. The tertiary oil recovery plus the secondary waterflood recovery can exceed the oil recovery in a secondary polymer flood in dolomite-viscous oil-brine system. These experiments were repeated in a Berea-oil-brine system which showed that the oil recovered in the secondary polymer flood was similar to the cumulative oil recovery in the tertiary polymer flood. The high

  1. Parametric analysis of surfactant-aided imbibition in fractured carbonates.

    Science.gov (United States)

    Adibhatla, B; Mohanty, K K

    2008-01-15

    Many carbonate oil reservoirs are oil-wet and fractured; waterflood recovery is very low. Dilute surfactant solution injection into the fractures can improve oil production from the matrix by altering the wettability of the rock to a water-wetting state. A 2D, two-phase, multicomponent, finite-volume, fully-implicit numerical simulator calibrated with our laboratory results is used to assess the sensitivity of the process to wettability alteration, IFT reduction, oil viscosity, surfactant diffusivity, matrix block dimensions, and permeability heterogeneity. Capillarity drives the oil production at the early stage, but gravity is the major driving force afterwards. Surfactants which alter the wettability to a water-wet regime give higher recovery rates for higher IFT systems. Surfactants which cannot alter wettability give higher recovery for lower IFT systems. As the wettability alteration increases the rate of oil recovery increases. Recovery rate decreases with permeability significantly for a low tension system, but only mildly for high tension systems. Increasing the block dimensions and increasing oil viscosity decreases the rate of oil recovery and is in accordance with the scaling group for a gravity driven process. Heterogeneous layers in a porous medium can increase or decrease the rate of oil recovery depending on the permeability and the aspect ratio of the matrix block.

  2. Carbon budget of tropical forests in Southeast Asia and the effects of deforestation: an approach using a process-based model and field measurements

    OpenAIRE

    Adachi, M; Ito, A; A. Ishida; W. R. Kadir; P. Ladpala; Yamagata, Y

    2011-01-01

    More reliable estimates of carbon (C) stock within forest ecosystems and C emission induced by deforestation are urgently needed to mitigate the effects of emissions on climate change. A process-based terrestrial biogeochemical model (VISIT) was applied to tropical primary forests of two types (a seasonal dry forest in Thailand and a rainforest in Malaysia) and one agro-forest (an oil palm plantation in Malaysia) to estimate the C budget of tropical ecosystems, including the impacts of...

  3. Carbon budget of tropical forests in Southeast Asia and the effects of deforestation: an approach using a process-based model and field measurements

    OpenAIRE

    Adachi, M; Ito, A; A. Ishida; W. R. Kadir; P. Ladpala; Yamagata, Y

    2011-01-01

    More reliable estimates of the carbon (C) stock within forest ecosystems and C emission induced by deforestation are urgently needed to mitigate the effects of emissions on climate change. A process-based terrestrial biogeochemical model (VISIT) was applied to tropical primary forests of two types (a seasonal dry forest in Thailand and a rainforest in Malaysia) and one agro-forest (an oil palm plantation in Malaysia) to estimate the C budget of tropical ecosystems in Southeast Asia, including...

  4. Fine Formation During Brine-Crude Oil-Calcite Interaction in Smart Water Enhanced Oil Recovery for Caspian Carbonates

    DEFF Research Database (Denmark)

    Chakravarty, Krishna Hara; Fosbøl, Philip Loldrup; Thomsen, Kaj

    2015-01-01

    Modified sea water has been shown to affect the oil recovery fraction considerably during secondary and tertiary waterfloods. Available soluble potential ions (i.e. Ca2+, Mg2+ & SO42-) in the interacting waterflood (ITW) are suggested to play a key role in increasing the displacement efficiency...

  5. Self-Volatilization Approach to Mesoporous Carbon Nanotube/Silver Nanoparticle Hybrids: The Role of Silver in Boosting Li Ion Storage.

    Science.gov (United States)

    Jiang, Hao; Zhang, Haoxuan; Fu, Yao; Guo, Shaojun; Hu, Yanjie; Zhang, Ling; Liu, Yu; Liu, Honglai; Li, Chunzhong

    2016-01-26

    One of the biggest challenging issues of carbon nanomaterials for Li ion batteries (LIBs) is that they show low initial Coulombic efficiency (CE), leading to a limited specific capacity. Herein, we demonstrate a simple template self-volatilization strategy for in situ synthesis of mesoporous carbon nanotube/Ag nanoparticle (NP) hybrids (Ag-MCNTs) to boost the LIBs' performance. The key concept of Ag-MCNTs for enhancing LIBs is that a small trace of Ag NPs on MCNTS can greatly restrict the formation of a thicker solid electrolyte interphase film, which has been well verified by both transmission electron microscopy results and quantum density functional theory calculations, leading to the highest initial CE in all the reported carbon nanomaterials. This uncovered property of Ag NPs from Ag-MCNTs makes them exhibit a very high reversible capacity of 1637 mAh g(-1) after 400 discharge/charge cycles at 100 mA g(-1), approximately 5 times higher than the theoretical value of a graphite anode (372 mAh g(-1)), excellent rate capability, and long cycle life.

  6. Shape Fixing via Salt Recrystallization: A Morphology-Controlled Approach To Convert Nanostructured Polymer to Carbon Nanomaterial as a Highly Active Catalyst for Oxygen Reduction Reaction.

    Science.gov (United States)

    Ding, Wei; Li, Li; Xiong, Kun; Wang, Yao; Li, Wei; Nie, Yao; Chen, Siguo; Qi, Xueqiang; Wei, Zidong

    2015-04-29

    Herein, we report a "shape fixing via salt recrystallization" method to efficiently synthesize nitrogen-doped carbon material with a large number of active sites exposed to the three-phase zones, for use as an ORR catalyst. Self-assembled polyaniline with a 3D network structure was fixed and fully sealed inside NaCl via recrystallization of NaCl solution. During pyrolysis, the NaCl crystal functions as a fully sealed nanoreactor, which facilitates nitrogen incorporation and graphitization. The gasification in such a closed nanoreactor creates a large number of pores in the resultant samples. The 3D network structure, which is conducive to mass transport and high utilization of active sites, was found to have been accurately transferred to the final N-doped carbon materials, after dissolution of the NaCl. Use of the invented cathode catalyst in a proton exchange membrane fuel cell produces a peak power of 600 mW cm(-2), making this among the best nonprecious metal catalysts for the ORR reported so far. Furthermore, N-doped carbon materials with a nanotube or nanoshell morphology can be realized by the invented method.

  7. An Effective Approach towards the Immobilization of PtSn Nanoparticles on Noncovalent Modified Multi-Walled Carbon Nanotubes for Ethanol Electrooxidation

    Directory of Open Access Journals (Sweden)

    Xi Geng

    2016-03-01

    Full Text Available In this article, we describe an effective method to tether Pt and PtSn nanoparticles (NPs on polyelectrolyte modified multi-walled carbon nanotubes (MWCNTs for ethanol electrooxidation. By using a polymer wrapping technique, positively charged polyethyleneimine (PEI was attached onto carbon nanotubes (CNTs to provide preferential linking sites for metal precursors. Well-dispersed Pt and PtSn nanocrystals (2–5 nm were subsequently decorated on PEI-functionalized MWCNTs through the polyol reduction method. The successful non-covalent modification of MWCNTs was confirmed by Fourier transform infrared spectroscopy (FTIR and Zeta potential measurements. Energy dispersive X-ray (EDX spectrum indicates approximately 20 wt % Pt loading and a desirable Pt:Sn atomic ratio of 1:1. Electrochemical analysis demonstrated that the as-synthesized PtSn/PEI-MWCNTs nanocomposite exhibited improved catalytic activity and higher poison tolerance for ethanol oxidation as compared to Pt/PEI-MWCNTs and commercial Pt/XC-72 catalysts. The enhanced electrochemical performance may be attributed to the uniform dispersion of NPs as well as the mitigating of CO self-poisoning effect by the alloying of Sn element. This modification and synthetic strategy will be studied further to develop a diversity of carbon supported Pt-based hybrid nanomaterials for electrocatalysis.

  8. Inferring long-term carbon sequestration from tree rings at Harvard Forest: A calibration approach using tree ring widths and geochemistry / flux tower data

    Science.gov (United States)

    Belmecheri, S.; Maxwell, S.; Davis, K. J.; Alan, T. H.

    2012-12-01

    Improving the prediction skill of terrestrial carbon cycle models is important for reducing the uncertainties in global carbon cycle and climate projections. Additional evaluation and calibration of carbon models is required, using both observations and long-term proxy-derived data. Centennial-length data could be obtained from tree-rings archives that provide long continuous series of past forest growth changes with accurate annual resolution. Here we present results from a study conducted at Harvard Forest (Petersham, Massachusetts). The study examines the potential relationship between δ13C in dominant trees and GPP and/or NEE measured by the Harvard Forest flux tower (1992-2010). We have analyzed the δ13C composition of late wood-cellulose over the last 18 years from eastern hemlock (Tsuga canadensis) and northern red oak (Quercus rubra) trees growing in the flux tower footprint. δ13C values, corrected for the declining trend of atmospheric δ13C, show a decreasing trend from 1992 to 2010 and therefore a significant increase in discrimination (Δ). The intra-cellular CO2 (Ci) calculated from Δ shows a significant increase for both tree species and follows the same rate of atmospheric CO2 (Ca) increase (Ci/Ca increases). Interestingly, the net Ci and Δ increase observed for both species did not result in an increase of the iWUE. Ci/Ca is strongly related to the growing season Palmer Drought Severity Index (PDSI) for both species thus indicating a significant relationship between soil moisture conditions and stomatal conductance. The Ci trend is interpreted as a result of higher CO2 assimilation in response to increasing soil moisture allowing a longer stomata opening and therefore stimulating tree growth. This interpretation is consistent with the observed increase in GPP and the strengthening of the carbon sink (more negative NEE). Additionally, the decadal trends of basal area increment (BAI) calculated from tree-ring widths exhibit a positive trend over

  9. Improving the Spatial Prediction of Soil Organic Carbon Stocks in a Complex Tropical Mountain Landscape by Methodological Specifications in Machine Learning Approaches.

    Science.gov (United States)

    Ließ, Mareike; Schmidt, Johannes; Glaser, Bruno

    2016-01-01

    Tropical forests are significant carbon sinks and their soils' carbon storage potential is immense. However, little is known about the soil organic carbon (SOC) stocks of tropical mountain areas whose complex soil-landscape and difficult accessibility pose a challenge to spatial analysis. The choice of methodology for spatial prediction is of high importance to improve the expected poor model results in case of low predictor-response correlations. Four aspects were considered to improve model performance in predicting SOC stocks of the organic layer of a tropical mountain forest landscape: Different spatial predictor settings, predictor selection strategies, various machine learning algorithms and model tuning. Five machine learning algorithms: random forests, artificial neural networks, multivariate adaptive regression splines, boosted regression trees and support vector machines were trained and tuned to predict SOC stocks from predictors derived from a digital elevation model and satellite image. Topographical predictors were calculated with a GIS search radius of 45 to 615 m. Finally, three predictor selection strategies were applied to the total set of 236 predictors. All machine learning algorithms-including the model tuning and predictor selection-were compared via five repetitions of a tenfold cross-validation. The boosted regression tree algorithm resulted in the overall best model. SOC stocks ranged between 0.2 to 17.7 kg m-2, displaying a huge variability with diffuse insolation and curvatures of different scale guiding the spatial pattern. Predictor selection and model tuning improved the models' predictive performance in all five machine learning algorithms. The rather low number of selected predictors favours forward compared to backward selection procedures. Choosing predictors due to their indiviual performance was vanquished by the two procedures which accounted for predictor interaction. PMID:27128736

  10. Helicobacter pylori seropositivity's association with markers of iron, 1-carbon metabolism, and antioxidant status among US adults: a structural equations modeling approach.

    Directory of Open Access Journals (Sweden)

    May A Beydoun

    Full Text Available We tested a model in which Helicobacter pylori seropositivity (Hps predicted iron status, which in turn acted as a predictor for markers of 1-C metabolism that were then allowed to predict antioxidant status.National Health and Nutrition Examination Surveys (NHANES 1999-2000 cross-sectional data among adults aged 20-85 y were analyzed (n = 3,055. Markers of Hps, iron status (serum ferritin and transferrin saturation (TS; 1-C metabolism (serum folate (FOLserum, B-12, total homocysteine (tHcy, methylmalonic acid (MMA and antioxidant status (vitamins A and E were entered into a structural equations model (SEM.Predictors of Hps included older age, lower education and income, racial/ethnic groups (lowest among Non-Hispanic Whites, and lifetime cigarette smoking. SEM modeling indicated that Hps had a direct inverse relationship with iron status (combining serum ferritin and TS which in turn was positively related to 1-C metabolites (higher serum folate, B-12 or lower tHcy/MMA that were positively associated with antioxidant status (combining serum vitamins A and E. Another pathway that was found bypassed 1-C metabolites (Hps → Iron_st → Antiox. The sum of all indirect effects from Hps combining both pathways and the other indirect pathways in the model (Hps → Iron_st → OneCarbon; Hps →OneCarbon →Antiox was estimated at β = -0.006±0.003, p<0.05.In sum, of the total effect of H. pylori seropositivity on antioxidant status, two significant indirect pathways through Iron status and 1-Carbon metabolites were found. Randomized controlled trials should be conducted to uncover the concomitant causal effect of H. pylori eradication on improving iron status, folate, B-12 and antioxidant status among H. pylori seropositive individuals.

  11. Improving the Spatial Prediction of Soil Organic Carbon Stocks in a Complex Tropical Mountain Landscape by Methodological Specifications in Machine Learning Approaches.

    Science.gov (United States)

    Ließ, Mareike; Schmidt, Johannes; Glaser, Bruno

    2016-01-01

    Tropical forests are significant carbon sinks and their soils' carbon storage potential is immense. However, little is known about the soil organic carbon (SOC) stocks of tropical mountain areas whose complex soil-landscape and difficult accessibility pose a challenge to spatial analysis. The choice of methodology for spatial prediction is of high importance to improve the expected poor model results in case of low predictor-response correlations. Four aspects were considered to improve model performance in predicting SOC stocks of the organic layer of a tropical mountain forest landscape: Different spatial predictor settings, predictor selection strategies, various machine learning algorithms and model tuning. Five machine learning algorithms: random forests, artificial neural networks, multivariate adaptive regression splines, boosted regression trees and support vector machines were trained and tuned to predict SOC stocks from predictors derived from a digital elevation model and satellite image. Topographical predictors were calculated with a GIS search radius of 45 to 615 m. Finally, three predictor selection strategies were applied to the total set of 236 predictors. All machine learning algorithms-including the model tuning and predictor selection-were compared via five repetitions of a tenfold cross-validation. The boosted regression tree algorithm resulted in the overall best model. SOC stocks ranged between 0.2 to 17.7 kg m-2, displaying a huge variability with diffuse insolation and curvatures of different scale guiding the spatial pattern. Predictor selection and model tuning improved the models' predictive performance in all five machine learning algorithms. The rather low number of selected predictors favours forward compared to backward selection procedures. Choosing predictors due to their indiviual performance was vanquished by the two procedures which accounted for predictor interaction.

  12. Improving the Spatial Prediction of Soil Organic Carbon Stocks in a Complex Tropical Mountain Landscape by Methodological Specifications in Machine Learning Approaches.

    Directory of Open Access Journals (Sweden)

    Mareike Ließ

    Full Text Available Tropical forests are significant carbon sinks and their soils' carbon storage potential is immense. However, little is known about the soil organic carbon (SOC stocks of tropical mountain areas whose complex soil-landscape and difficult accessibility pose a challenge to spatial analysis. The choice of methodology for spatial prediction is of high importance to improve the expected poor model results in case of low predictor-response correlations. Four aspects were considered to improve model performance in predicting SOC stocks of the organic layer of a tropical mountain forest landscape: Different spatial predictor settings, predictor selection strategies, various machine learning algorithms and model tuning. Five machine learning algorithms: random forests, artificial neural networks, multivariate adaptive regression splines, boosted regression trees and support vector machines were trained and tuned to predict SOC stocks from predictors derived from a digital elevation model and satellite image. Topographical predictors were calculated with a GIS search radius of 45 to 615 m. Finally, three predictor selection strategies were applied to the total set of 236 predictors. All machine learning algorithms-including the model tuning and predictor selection-were compared via five repetitions of a tenfold cross-validation. The boosted regression tree algorithm resulted in the overall best model. SOC stocks ranged between 0.2 to 17.7 kg m-2, displaying a huge variability with diffuse insolation and curvatures of different scale guiding the spatial pattern. Predictor selection and model tuning improved the models' predictive performance in all five machine learning algorithms. The rather low number of selected predictors favours forward compared to backward selection procedures. Choosing predictors due to their indiviual performance was vanquished by the two procedures which accounted for predictor interaction.

  13. A Statistical Estimation Approach for Quantitative Concentrations of Compounds Lacking Authentic Standards/Surrogates Based on Linear Correlations between Directly Measured Detector Responses and Carbon Number of Different Functional Groups

    Directory of Open Access Journals (Sweden)

    Yong-Hyun Kim

    2013-01-01

    Full Text Available A statistical approach was investigated to estimate the concentration of compounds lacking authentic standards/surrogates (CLASS. As a means to assess the reliability of this approach, the response factor (RF of CLASS is derived by predictive equations based on a linear regression (LR analysis between the actual RF (by external calibration of 18 reference volatile organic compounds (VOCs consisting of six original functional groups and their physicochemical parameters ((1 carbon number (CN, (2 molecular weight (MW, and (3 boiling point (BP. If the experimental bias is estimated in terms of percent difference (PD between the actual and projected RF, the least bias for 18 VOCs is found from CN (17.9±19.0%. In contrast, the PD values against MW and BP are 40.6% and 81.5%, respectively. Predictive equations were hence derived via an LR analysis between the actual RF and CN for 29 groups: (1 one group consisting of all 18 reference VOCs, (2 three out of six original functional groups, and (3 25 groups formed randomly from the six functional groups. The applicability of this method was tested by fitting these 29 equations into each of the six original functional groups. According to this approach, the mean PD for 18 compounds dropped as low as 5.60±5.63%. This approach can thus be used as a practical tool to assess the quantitative data for CLASS.

  14. Synthesis of nano-sized cyanide ion-imprinted polymer via non-covalent approach and its use for the fabrication of a CN(-)-selective carbon nanotube impregnated carbon paste electrode.

    Science.gov (United States)

    Alizadeh, Taher; Sabzi, Reza Emamali; Alizadeh, Hassan

    2016-01-15

    Nano-sized CN(-)-imprinted polymer was synthesized by the copolymerization of methyl methacrylic acid (MAA), vinyl pyridine (VP) and ethylene glycol dimethacrylate in the presence of cyanide ion. The obtained polymeric nanoparticles were incorporated with carbon paste electrode (CPE) to produce a CN(-)-selective electrode. Functional monomer kind had crucial influence on the efficiency of the sensor. The presence of both VP and MAA in the structure of the imprinted polymer improved the sensing characteristics of the electrode. Also, the mole ratio of MAA/VP, cross-liker kind, cross-linker amount, solvent kind and amount were found to be effective factors in the electrode behavior. Presence of little amount of multi-walled carbon nanotubes (MWCNTs) in the CPE improved the detection range and response time of the electrode at the expense of small decrease in Nernstian slope. The electrode, containing CN(-)-imprinted polymer and MWCNTs showed a dynamic linear range of 1×10(-6)-1×10(-1)mol L(-1), Nernstian slope of 46.3±(0.6) mV and detection limit of 7.5×10(-7)mol L(-1); whereas, the same electrode in the absence of MWCNTs led to linear range, Nernstian slope and detection limit of 1×10(-5)-1×10(-1)molL(-1), 55.3±(0.7) mV and 8×10(-6)mol L(-1), respectively. The utility of the electrodes was checked by determination of cyanide ion in some real samples. PMID:26592581

  15. Comparison of measurement of aerosol black carbon at Barrow, Alaska, and Wrangel Island, USSR: An approach to estimating the deposition of soot to snow and ice surfaces

    International Nuclear Information System (INIS)

    During late spring 1989 (and 1990, in planning), measurements of aerosol black carbon were, made on Wrangel Island in the Soviet Arctic to complement the routine measurements at the NOAA/GMCC Barrow Observatory of this combustion-derived pollutant. The results are compared during time intervals in which trajectories led from Barrow to Wrangel Island, with typical transit times of one day. The intervening surface is entirely frozen ocean, without land masses' topography to complicate air flow, nor any human habitation combustion sources. Aerosol black carbon is chemically unreactive, and so any losses in transit will be due to deposition onto the frozen ocean surface. This species is strongly optically absorbing, and a small aerosol deposition from the Arctic haze may reduce the surface albedo sufficiently to increase the absorption of solar radiation in spring and lead to premature, thawing. The authors discuss the possible effects of the deposition of soot from the Arctic haze onto high latitude snow and ice cover in terms of climate change

  16. Carbon for sensing devices

    CERN Document Server

    Tagliaferro, Alberto

    2015-01-01

    This book reveals why carbon is playing such an increasingly prominent role as a sensing material. The various steps that transform a raw material in a sensing device are thoroughly presented and critically discussed.  The authors deal with all aspects of carbon-based sensors, starting from the various hybridization and allotropes of carbon, with specific focus on micro and nanosized carbons (e.g., carbon nanotubes, graphene) and their growth processes. The discussion then moves to the role of functionalization and the different routes to achieve it. Finally, a number of sensing applications in various fields are presented, highlighting the connection with the basic properties of the various carbon allotropes.  Readers will benefit from this book’s bottom-up approach, which starts from the local bonding in carbon solids and ends with sensing applications, linking the local hybridization of carbon atoms and its modification by functionalization to specific device performance. This book is a must-have in th...

  17. Novel carbon nanostructures

    International Nuclear Information System (INIS)

    The discovery of carbon nanotubes in 1991 opened up a challenging new area of research, because they are expected to be ideal building blocks for nanoscale applications due to their extraordinary mechanical and electronic properties. Various production methods have been developed, however precise control of nanotube morphology (e.g. length, diameter) has yet to be realised, a fact which has delayed industrial exploitation. Thus a comprehensive understanding of nanotube growth is essential, and this thesis is concerned with this important problem, i.e. the controlled production of novel carbon nanomaterials. Chapter 1 surveys production methods for fullerenes, carbon nanotubes and other carbon-based materials, such as fibres, particles etc. The sophisticated tools required for this work, e.g. high resolution transmission electron microscopy (HRTEM), high resolution electron energy loss spectroscopy (HREELS), etc. are reviewed in Chapter 2. Chapter 3 describes a novel approach to carbon nanotubes, using laser etching techniques, which generates aligned tubes of uniform diameter and length. The mode of catalyst preparation, as well as the nature of the precursor, play crucial roles in this process. The preparation of modified carbon nanotubes by the pyrolysis of metallocene, e.g. ferrocene in conjunction with various hydrocarbons, is discussed in Chapter 4. Superconducting interference device measurements (SQUID) show that Fe-filled carbon nanotubes exhibit enhanced coercivities in the 430-1070 Oe range, i.e. greater than those reported for Ni and Co nanowires. Carbon nanotubes can be also modified by replacing atoms of the carbon network with nitrogen, boron or both. The creation of large arrays of nitrogen-doped carbon nanotubes, for example CNx nanofibres, as well as the formation of BxCyNz onions is described in Chapter 5. Electron irradiation of these onions generates pure carbon onions. Finally (Chapter 6), the catalytic behaviour of metal particles in different

  18. Sustainable carbon materials from hydrothermal processes

    CERN Document Server

    Titirici, Maria-Magdalena

    2013-01-01

    The production of low cost and environmentally friendly high performing carbon materials is crucial for a sustainable future. Sustainable Carbon Materials from Hydrothermal Processes describes a sustainable and alternative technique to produce carbon from biomass in water at low temperatures, a process known as Hydrothermal Carbonization (HTC). Sustainable Carbon Materials from Hydrothermal Processes presents an overview of this new and rapidly developing field, discussing various synthetic approaches, characterization of the final products, and modern fields of application fo

  19. Water and Carbon Fluxes in a Semi-Arid Region Floodplain: Multiple Approaches to Constrain Estimates of Seasonal- and Depth Dependent Fluxes at Rifle, Colorado

    Science.gov (United States)

    Tokunaga, T. K.; Wan, J.; Dong, W.; Kim, Y.; Williams, K. H.; Conrad, M. E.; Christensen, J. N.; Bill, M.; Faybishenko, B.; Hobson, C.; Dayvault, R.; Long, P. E.; Hubbard, S. S.

    2014-12-01

    The importance of floodplains as links between watersheds and rivers highlights the need to understand water and carbon fluxes within floodplain profiles, from their surface soil, through the vadose zone and underlying groundwater. Here, we present results of field and laboratory measurements conducted to quantify fluxes at a remediated uranium/vanadium mill tailings site on a floodplain at Rifle, Colorado. This semi-arid site has a vegetated, locally derived fill soil that replaced the original milling-contaminated soil to a depth of about 1.5 m. The fill soil overlies about 4.5 m of native sandy and cobbly alluvium containing the shallow aquifer. The aquifer generally drains into the Colorado River and is underlain by low permeability Wasatch Formation shale. Within this system, key issues being investigated include water and carbon fluxes between the vadose zone and aquifer, and CO2 fluxes through the vadose zone soil out to the atmosphere. Magnitudes of these fluxes are typically low, thus challenging to measure, yet increasingly important to quantify given the expansion of arid and semi-arid regions under changing climate. The results of field investigations demonstrated that the annual water table rise and fall are driven by snowmelt runoff into the Colorado River in late spring to early summer. Tensiometer data indicate that net recharge from the deeper part of the vadose zone into groundwater occurs later in summer, after water table decline. The effectiveness of summer evapotranspiration in limiting groundwater recharge is reflected in water potentials decreasing to as low as -3 MPa within the upper 1.5 m of the vadose zone. Examination of the historical precipitation record further indicates that net recharge only occurs in years with above-average precipitation during winter and spring. These short intervals of net recharge also facilitate C transport into groundwater because of higher organic C concentrations in the vadose zone. Fluxes of CO2 measured

  20. Effects of heat and drought on carbon and water dynamics in a regenerating semi-arid pine forest: a combined experimental and modeling approach

    Directory of Open Access Journals (Sweden)

    N. K. Ruehr

    2014-01-01

    Full Text Available Increasing summer temperatures and a reduction in precipitation will enhance drought stress in Mediterranean and semi-arid ecosystems. Predicting the net effects on forests' carbon and water balance will depend on our ability to disentangle the sensitivity of component fluxes responding to increasing soil and atmospheric drought. Here we studied carbon and water dynamics in a semi-arid regenerating ponderosa pine forest using field observations and process based modeling. Field observations of two summer dry seasons were used to calibrate a soil-plant-atmosphere (SPA model. In addition, the ecosystem's response to reduced soil drought was quantified based on a field watering experiment and evaluated with the model. Further, the SPA model was used to estimate the relative effects of increasing soil and atmospheric drought over time, by simulating temperature and precipitation scenarios for 2040 and 2080. The seasonality and drought response of ecosystem fluxes was well captured by the calibrated SPA model. Dramatic increases in summer water availability during seasonal drought had a small effect on pine physiology in both the watering experiment and the model. This clearly demonstrates that atmospheric drought induced a strong limitation on carbon uptake in young ponderosa pine due to tight regulation of stomatal conductance. Moreover, simulations showed that net ecosystem exchange (NEE and gross primary productivity (GPP were about three times more affected by summer heat and increased evaporative demand than by reductions in summer precipitation. Annual NEE decreased by 38% in response to extreme summer conditions as predicted to occur in 2080 (June–August: +4.5 °C, because of a strong decline in GPP (−17% while heterotrophic respiration was relatively unaffected (−1%. Considering warming trends across all seasons (September–May: +3 °C and June–August: +4.5 °C, the negative drought effects were largely compensated by an earlier

  1. Comparing microbial and chemical approaches for modelling soil organic carbon decomposition using the DecoChem v1.0 and DecoBio v1.0 models

    Directory of Open Access Journals (Sweden)

    G. Xenakis

    2014-01-01

    Full Text Available Soil organic matter is a vast store of carbon, with a critical role in the global carbon cycle. Despite its importance the dynamics of soil organic carbon decomposition, under the impact of climate change or changing litter inputs, are poorly understood. Current biogeochemical models usually lack microbial processes and thus miss an important feedback when considering the fate of carbon. Here we use a series of modelling experiments to evaluate two different model structures, one with a standard first order kinetic representation of soil decomposition (DecoChem v1.0, hearafter chemical model and one with control of soil decomposition through microbial activity (DecoBio v1.0, hereafter biological model. We tested two hypotheses. First, that increased litter inputs and glucose addition prime microbial activity and reduce soil carbon stocks in the biological model, but increase C stocks in the chemical model. Experiments provided some support for this hypothesis, with soil C stocks increasing in the chemical model in response to litter increases. In the biological model, responses to changed litter quantity were more rapid, but with the residence time of soil C altering such that soil C stocks were buffered. However, in the biological model there was a strong response to increased glucose additions (i.e., changes in litter quality, with significant losses to soil C stocks over time, driven by priming. Secondly, we hypothesised that warming will stimulate decomposition in the chemical model, and loss of C, but in the biological model soil C will be less sensitive to warming, due to complex microbial feedbacks. The experiments supported this hypothesis, with the chemical model soil C residence times and steady state C stocks adjusting strongly with temperature changes, extending over decades. On the other hand, the biological model showed a rapid response to temperature that subsided after a few years, with total soil C stocks largely unchanged. The

  2. Functioning of the planktonic ecosystem of the Rhone River plume (NW Mediterranean during spring and its impact on the carbon export: a field data and 3-D modelling combined approach

    Directory of Open Access Journals (Sweden)

    P. A. Auger

    2010-12-01

    Full Text Available Low-salinity water (LSW, Salinity < 37.5 lenses detached from the Rhone River plume under specific wind conditions tend to favour the biological productivity and potentially a transfer of energy to higher trophic levels on the Gulf of Lions (GoL. A field cruise conducted in May 2006 (BIOPRHOFI followed some LSW lenses by using a lagrangian strategy. A thorough analysis of the available data set enabled to further improve our understanding of the LSW lenses' functioning and their potential influence on marine ecosystems. Through an innovative 3-D coupled hydrodynamic-biogeochemical modelling approach, a specific calibration dedicated to river plume ecosystems was then proposed and validated on field data. Exploring the role of ecosystems on the particulate organic carbon (POC export and deposition on the shelf, a sensitivity analysis to the particulate organic matter inputs from the Rhone River was carried out from 1 April to 15 July 2006. Over such a typical end-of-spring period marked by moderate floods, the main deposition area of POC was identified alongshore between 0 and 50 m depth on the GoL, extending the Rhone prodelta to the west towards the exit of the shelf. Moreover, the main deposition area of terrestrial POC was found on the prodelta region, which confirms recent results from sediment data. The averaged daily deposition of particulate organic carbon over the whole GoL is estimated by the model between 40 and 80 mgC/m2, which is in the range of previous secular estimations. The role of ecosystems on the POC export toward sediments or offshore areas was actually highlighted and feedbacks between ecosystems and particulate organic matters are proposed to explain paradoxical model results to the sensitivity test. In fact, the conversion of organic matter in living organisms would increase the retention of organic matter in the food web and this matter transfer along the food web could explain the minor quantity of POC of

  3. Near-ambient X-ray photoemission spectroscopy and kinetic approach to the mechanism of carbon monoxide oxidation over lanthanum substituted cobaltites

    Energy Technology Data Exchange (ETDEWEB)

    Hueso, J. L.; Martinez-Martinez, D.; Cabalerro, Alfonso; Gonzalez-Elipe, Agustin Rodriguez; Mun, Bongjin Simon; Salmeron, Miquel

    2009-07-31

    We have studied the oxidation of carbon monoxide over a lanthanum substituted perovskite (La0.5Sr0.5CoO3-d) catalyst prepared by spray pyrolysis. Under the assumption of a first-order kinetics mechanism for CO, it has been found that the activation energy barrier of the reaction changes from 80 to 40 kJ mol-1 at a threshold temperature of ca. 320 oC. In situ XPS near-ambient pressure ( 0.2 torr) shows that the gas phase oxygen concentration over the sample decreases sharply at ca. 300 oC. These two observations suggest that the oxidation of CO undergoes a change of mechanism at temperatures higher than 300 oC.

  4. A hypersaline microbial mat from the Pacific Atoll Kiritimati: insights into composition and carbon fixation using biomarker analyses and a 13C-labeling approach.

    Science.gov (United States)

    Bühring, S I; Smittenberg, R H; Sachse, D; Lipp, J S; Golubic, S; Sachs, J P; Hinrichs, K-U; Summons, R E

    2009-06-01

    Modern microbial mats are widely recognized as useful analogs for the study of biogeochemical processes relevant to paleoenvironmental reconstruction in the Precambrian. We combined microscopic observations and investigations of biomarker composition to investigate community structure and function in the upper layers of a thick phototrophic microbial mat system from a hypersaline lake on Kiritimati (Christmas Island) in the Northern Line Islands, Republic of Kiribati. In particular, an exploratory incubation experiment with (13)C-labeled bicarbonate was conducted to pinpoint biomarkers from organisms actively fixing carbon. A high relative abundance of the cyanobacterial taxa Aphanocapsa and Aphanothece was revealed by microscopic observation, and cyanobacterial fatty acids and hydrocarbons showed (13)C-uptake in the labeling experiment. Microscopic observations also revealed purple sulfur bacteria (PSB) in the deeper layers. A cyclic C(19:0) fatty acid and farnesol were attributed to this group that was also actively fixing carbon. Background isotopic values indicate Calvin-Benson cycle-based autotrophy for cycC(19:0) and farnesol-producing PSBs. Biomarkers from sulfate-reducing bacteria (SRB) in the top layer of the mat and their (13)C-uptake patterns indicated a close coupling between SRBs and cyanobacteria. Archaeol, possibly from methanogens, was detected in all layers and was especially abundant near the surface where it contained substantial amounts of (13)C-label. Intact glycosidic tetraether lipids detected in the deepest layer indicated other archaea. Large amounts of ornithine and betaine bearing intact polar lipids could be an indicator of a phosphate-limited ecosystem, where organisms that are able to substitute these for phospholipids may have a competitive advantage.

  5. Microbially mediated mineral carbonation

    Science.gov (United States)

    Power, I. M.; Wilson, S. A.; Dipple, G. M.; Southam, G.

    2010-12-01

    Mineral carbonation involves silicate dissolution and carbonate precipitation, which are both natural processes that microorganisms are able to mediate in near surface environments (Ferris et al., 1994; Eq. 1). (Ca,Mg)SiO3 + 2H2CO3 + H2O → (Ca,Mg)CO3 + H2O + H4SiO4 + O2 (1) Cyanobacteria are photoautotrophs with cell surface characteristics and metabolic processes involving inorganic carbon that can induce carbonate precipitation. This occurs partly by concentrating cations within their net-negative cell envelope and through the alkalinization of their microenvironment (Thompson & Ferris, 1990). Regions with mafic and ultramafic bedrock, such as near Atlin, British Columbia, Canada, represent the best potential sources of feedstocks for mineral carbonation. The hydromagnesite playas near Atlin are a natural biogeochemical model for the carbonation of magnesium silicate minerals (Power et al., 2009). Field-based studies at Atlin and corroborating laboratory experiments demonstrate the ability of a microbial consortium dominated by filamentous cyanobacteria to induce the precipitation of carbonate minerals. Phototrophic microbes, such as cyanobacteria, have been proposed as a means for producing biodiesel and other value added products because of their efficiency as solar collectors and low requirement for valuable, cultivable land in comparison to crops (Dismukes et al., 2008). Carbonate precipitation and biomass production could be facilitated using specifically designed ponds to collect waters rich in dissolved cations (e.g., Mg2+ and Ca2+), which would allow for evapoconcentration and provide an appropriate environment for growth of cyanobacteria. Microbially mediated carbonate precipitation does not require large quantities of energy or chemicals needed for industrial systems that have been proposed for rapid carbon capture and storage via mineral carbonation (e.g., Lackner et al., 1995). Therefore, this biogeochemical approach may represent a readily

  6. Tracing oxygen variations and its biogeochemical expression during the late hauterivian Faraoni Event: A multi tracers approach using paired carbon, nitrogen, sulfur isotopes and trace metallic elements

    Science.gov (United States)

    Thomazo, Christophe; Riquier, Laurent; Martinez, Mathieu; Mathieu, Olivier

    2013-04-01

    During the Cretaceous, several occurrences of Oceanic Anoxic Event (OAE) are described in the sedimentary record. Among them, the late Hauterivian Faraoni Event has been extensively studied in several locations including Italy, Switzerland, France and Spain and interpreted as a short-lived OAE from palaeontological, sedimentological and geochemical observations. However, the biogeochemical response to water column oxygen depletion is poorly documented and mostly stands on carbon carbonates isotopes during the Faraoni event. In order to bring further insights into the biogeochemical cycles modifications during O2 variations across the Faraoni Event, we performed an integrated geochemical study including C, N and S isotopes together with paleo-redox tracers (i.e. trace metallic elements and iron speciation) on about 25 samples from the Río Argos section (S.E. Spain). δ13Ccarb increases from 1.23‰ to 1.61‰ at the base of the studied section before the Faraoni event. Maximum values, ranging between 1.21‰ and 1.73‰, are observed within this event and are followed by a rapid decrease in δ13Ccarb values down to 0.50‰ toward the top of the section. δ13Corg and TOC values show a narrow range of variations around -26.3±0.3‰ and 0.15±0.3 wt.%, respectively. Only one sample records a higher TOC content up to 1.53 wt.% at the very base of the Faraoni Event while no sensible variations can be deduced form organic carbon isotopes. Bulk sediments nitrogen isotopes have a mean value of 2.3±0.2‰ and nitrogen contents vary between 320 and 790 ppm. A noticeable δ15N excursion (i.e. 0.86‰) is observed at the very base of the Faraoni Event and is associated with the highest TOC value. Sulfur contents vary between 100 and 2480 ppm, the highest content being recorded just bellow the base of the Faraoni Event. δ34S show a wide range of variations from -44.8 to -10.1‰ on a short scale without easily recognizable stratigraphic trend. Finally, slight increases of

  7. Greenhouse gas emissions and stocks of soil carbon and nitrogen from a 20-year fertilised wheat-maize intercropping system: A model approach.

    Science.gov (United States)

    Zhang, Xubo; Xu, Minggang; Liu, Jian; Sun, Nan; Wang, Boren; Wu, Lianhai

    2016-02-01

    Accurate modelling of agricultural management impacts on greenhouse gas emissions and the cycling of carbon and nitrogen is complicated due to interactions between various processes and the disturbance caused by field management. In this study, a process-based model, the Soil-Plant-Atmosphere Continuum System (SPACSYS), was used to simulate the effects of different fertilisation regimes on crop yields, the dynamics of soil organic carbon (SOC) and total nitrogen (SN) stocks from 1990 to 2010, and soil CO2 (2007-2010) and N2O (2007-2008) emissions based on a long-term fertilisation experiment with a winter-wheat (Triticum Aestivum L.) and summer-maize (Zea mays L.) intercropping system in Eutric Cambisol (FAO) soil in southern China. Three fertilisation treatments were 1) unfertilised (Control), 2) chemical nitrogen, phosphorus and potassium (NPK), and 3) NPK plus pig manure (NPKM). Statistical analyses indicated that the SPACSYS model can reasonably simulate the yields of wheat and maize, the evolution of SOC and SN stocks and soil CO2 and N2O emissions. The simulations showed that the NPKM treatment had the highest values of crop yields, SOC and SN stocks, and soil CO2 and N2O emissions were the lowest from the Control treatment. Furthermore, the simulated results showed that manure amendment along with chemical fertiliser applications led to both C (1017 ± 470 kg C ha(-1) yr(-1)) and N gains (91.7 ± 15.1 kg N ha(-1) yr(-1)) in the plant-soil system, while the Control treatment caused a slight loss in C and N. In conclusion, the SPACSYS model can accurately simulate the processes of C and N as affected by various fertilisation treatments in the red soil. Furthermore, application of chemical fertilisers plus manure could be a suitable management for ensuring crop yield and sustaining soil fertility in the red soil region, but the ratio of chemical fertilisers to manure should be optimized to reduce C and N losses to the environment.

  8. Greenhouse gas emissions and stocks of soil carbon and nitrogen from a 20-year fertilised wheat-maize intercropping system: A model approach.

    Science.gov (United States)

    Zhang, Xubo; Xu, Minggang; Liu, Jian; Sun, Nan; Wang, Boren; Wu, Lianhai

    2016-02-01

    Accurate modelling of agricultural management impacts on greenhouse gas emissions and the cycling of carbon and nitrogen is complicated due to interactions between various processes and the disturbance caused by field management. In this study, a process-based model, the Soil-Plant-Atmosphere Continuum System (SPACSYS), was used to simulate the effects of different fertilisation regimes on crop yields, the dynamics of soil organic carbon (SOC) and total nitrogen (SN) stocks from 1990 to 2010, and soil CO2 (2007-2010) and N2O (2007-2008) emissions based on a long-term fertilisation experiment with a winter-wheat (Triticum Aestivum L.) and summer-maize (Zea mays L.) intercropping system in Eutric Cambisol (FAO) soil in southern China. Three fertilisation treatments were 1) unfertilised (Control), 2) chemical nitrogen, phosphorus and potassium (NPK), and 3) NPK plus pig manure (NPKM). Statistical analyses indicated that the SPACSYS model can reasonably simulate the yields of wheat and maize, the evolution of SOC and SN stocks and soil CO2 and N2O emissions. The simulations showed that the NPKM treatment had the highest values of crop yields, SOC and SN stocks, and soil CO2 and N2O emissions were the lowest from the Control treatment. Furthermore, the simulated results showed that manure amendment along with chemical fertiliser applications led to both C (1017 ± 470 kg C ha(-1) yr(-1)) and N gains (91.7 ± 15.1 kg N ha(-1) yr(-1)) in the plant-soil system, while the Control treatment caused a slight loss in C and N. In conclusion, the SPACSYS model can accurately simulate the processes of C and N as affected by various fertilisation treatments in the red soil. Furthermore, application of chemical fertilisers plus manure could be a suitable management for ensuring crop yield and sustaining soil fertility in the red soil region, but the ratio of chemical fertilisers to manure should be optimized to reduce C and N losses to the environment. PMID:26615226

  9. Facile, soot free approach toward synthesis of carbon nanoropes via chemical vapor deposition of acetylene in the presence of MnFe2O4 coated on stainless steel

    Science.gov (United States)

    Dhand, Vivek; Bharadwaj, S.; Amareshwari, K.; Himabindu, V.; Rhee, Kyong Yop; Park, Soo-Jin; Hui, David

    2015-12-01

    High density, soot free, novel and a facile approach toward synthesis of carbon nanoropes (CNRs) were successfully carried out in a chemical vapor deposition (CVD) process. Manganese ferrite (MnFe2O4) coated on stainless steel foil (SS 316 grade) was used as a catalyst to initiate the growth of CNR. The coated catalyst was introduced into the CVD and the chamber temperature was set at 700 °C later followed with the release of acetylene (50 sccm) and nitrogen (500 sccm) gas, respectively. Total reaction continued until 30 min. No purification or oxidation process of the soot was involved. Analysis reveals the presence of intermingled CNRs with semi crystalline nature of the sample. The elemental analysis confirms the presence of manganese and iron whereas Raman spectrum shows the characteristic narrow G and D bands. The sample displays a super-paramagnetic behavior and is thermally stable up to 500-550 °C presenting a strong exothermic reaction.

  10. Radiation Effects in Carbon Nanoelectronics

    Directory of Open Access Journals (Sweden)

    Cory D. Cress

    2012-07-01

    Full Text Available We experimentally investigate the effects of Co-60 irradiation on the electrical properties of single-walled carbon nanotube and graphene field-effect transistors. We observe significant differences in the radiation response of devices depending on their irradiation environment, and confirm that, under controlled conditions, standard dielectric hardening approaches are applicable to carbon nanoelectronics devices.

  11. Radiation Effects in Carbon Nanoelectronics

    OpenAIRE

    Cory D. Cress; McMorrow, Julian J.; Robinson, Jeremy T.; Landi, Brian J.; Seth M. Hubbard; Messenger, Scott R.

    2012-01-01

    We experimentally investigate the effects of Co-60 irradiation on the electrical properties of single-walled carbon nanotube and graphene field-effect transistors. We observe significant differences in the radiation response of devices depending on their irradiation environment, and confirm that, under controlled conditions, standard dielectric hardening approaches are applicable to carbon nanoelectronics devices.

  12. Differential pulse anodic stripping voltammetry for detection of As (III) by Chitosan-Fe(OH)3 modified glassy carbon electrode: A new approach towards speciation of arsenic.

    Science.gov (United States)

    Saha, Suparna; Sarkar, Priyabrata

    2016-09-01

    An efficient electrochemical sensor for As(III) was developed based on adsorption of arsenic on a specially modified electrodes at some applied potential and subsequent i) stripping at a fixed potential by anodic stripping voltammetry ii) analysis by generating surface plasmon resonance (SPR). The working glassy carbon electrode was modified by Chitosan-Fe(OH)3 composite and a reducing agent L-cysteine. The composite enhanced adsorption of As(III) and subsequent reduction to As(O) moieties and measurement by anodic stripping. The surface property of modified electrode was characterized by SEM, AFM, FTIR, XPS and electrochemistry was analyzed by impedance spectroscopy (EIS). Surface Plasmon resonance (SPR) was also employed to investigate the As(III) binding capability of polymer matrix. Several optimum voltammetric parameters e.g supporting electrolyte; 0.1M acetate buffer (pH 5.2) deposition potential, -0.9V; deposition time, 100s were established for anodic stripping voltammetry (ASV). A linear correlation was obtained in the range of 2-100ppb for ASV (R(2) 0.974) with limit of detection 0.072ppb. A variety of common coexistent ions such as Mn, Zn, Pb, Cu, Cd in water samples showed no interferences on the As (III) determination. The method was applied successfully to real samples collected from arsenic affected areas of West Bengal, India. PMID:27343601

  13. A Novel Approach for Determining Source–Receptor Relationships in Model Simulations: A Case Study of Black Carbon Transport in Northern Hemisphere Winter

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Po-Lun; Gattiker, J. R.; Liu, Xiaohong; Rasch, Philip J.

    2013-06-27

    A Gaussian process (GP) emulator is applied to quantify the contribution of local and remote emissions of black carbon (BC) on the BC concentrations in different regions using a Latin Hypercube sampling strategy for emission perturbations in the offline version of the Community Atmosphere Model Version 5.1 (CAM5) simulations. The source-receptor relationships are computed based on simulations constrained by a standard free-running CAM5 simulation and the ERA-Interim reanalysis product. The analysis demonstrates that the emulator is capable of retrieving the source-receptor relationships based on a small number of CAM5 simulations. Most regions are found susceptible to their local emissions. The emulator also finds that the source-receptor relationships retrieved from the model-driven and the reanalysis-driven simulations are very similar, suggesting that the simulated circulation in CAM5 resembles the assimilated meteorology in ERA-Interim. The robustness of the results provides confidence for applying the emulator to detect dose-response signals in the climate system.

  14. A fuzzy logic controller based approach to model the switching mechanism of the mammalian central carbon metabolic pathway in normal and cancer cells.

    Science.gov (United States)

    Dasgupta, Abhijit; Paul, Debjyoti; De, Rajat K

    2016-07-19

    Dynamics of large nonlinear complex systems, like metabolic networks, depend on several parameters. A metabolic pathway may switch to another pathway in accordance with the current state of parameters in both normal and cancer cells. Here, most of the parameter values are unknown to us. A fuzzy logic controller (FLC) has been developed here for the purpose of modeling metabolic networks by approximating the reasons for the behaviour of a system and applying expert knowledge to track switching between metabolic pathways. The simulation results can track the switching between glycolysis and gluconeogenesis, as well as glycolysis and pentose phosphate pathways (PPP) in normal cells. Unlike normal cells, pyruvate kinase (M2 isoform) (PKM2) switches alternatively between its two oligomeric forms, i.e. an active tetramer and a relatively low activity dimer, in cancer cells. Besides, there is a coordination among PKM2 switching and enzymes catalyzing PPP. These phenomena help cancer cells to maintain their high energy demand and macromolecular synthesis. However, the reduction of initial adenosine triphosphate (ATP) to a very low concentration, decreasing initial glucose uptake, destroying coordination between glycolysis and PPP, and replacement of PKM2 by its relatively inactive oligomeric form (dimer) or inhibition of the translation of PKM2 may destabilize the mutated control mechanism of the mammalian central carbon metabolic (CCM) pathway in cancer cells. The performance of the model is compared appropriately with some existing ones. PMID:27225801

  15. 2015 DOE Final UF Report. Effects of Warming the Deep Soil and Permafrost on Ecosystem Carbon Balance in Alaskan Tundra. A Coupled Measurement and Modeling Approach

    Energy Technology Data Exchange (ETDEWEB)

    Schuur, Edward [Univ. of Florida, Gainesville, FL (United States)

    2015-06-11

    The major research goal of this project was to understand and quantify the fate of carbon stored in permafrost ecosystems using a combination of field and laboratory experiments to measure isotope ratios and C fluxes in a tundra ecosystem exposed to experimental warming. Field measurements centered on the establishment of a two-factor experimental warming using a snow fence and open top chambers to increase winter and summer temperatures alone, and in combination, at a tundra field site at the Eight Mile Lake watershed near Healy, Alaska. The objective of this experimental warming was to significantly raise air and deep soil temperatures and increase the depth of thaw beyond that of previous warming experiments. Detecting the loss and fate of the old permafrost C pool remains a major challenge. Because soil C has been accumulating in these ecosystems over the past 10,000 years, there is a strong difference between the radiocarbon isotopic composition of C deep in the soil profile and permafrost compared to that near the soil surface. This large range of isotopic variability is unique to radiocarbon and provides a valuable and sensitive fingerprint for detecting the loss of old soil C as permafrost thaws.

  16. Priming of soil carbon decomposition in two inner Mongolia grassland soils following sheep dung addition: A study using13C natural abundance approach

    DEFF Research Database (Denmark)

    Ma, Xiuzhi; Ambus, Per; Wang, Shiping;

    2013-01-01

    To investigate the effect of sheep dung on soil carbon (C) sequestration, a 152 days incubation experiment was conducted with soils from two different Inner Mongolian grasslands, i.e. a Leymus chinensis dominated grassland representing the climax community (2.1% organic matter content...... with the two grassland soils and incubated under controlled conditions for analysis of 13C-CO2 emissions. Soil samples were taken at days 17, 43, 86, 127 and 152 after sheep dung addition to detect the δ 13C signal in soil and dung components. Analysis revealed that 16.9% and 16.6% of the sheep dung C had...... decomposed, of which 3.5% and 2.8% was sequestrated in the soils of L. chinensis and A. frigida grasslands, respectively, while the remaining decomposed sheep dung was emitted as CO 2. The cumulative amounts of C respired from dung treated soils during 152 days were 7-8 times higher than in the un...

  17. Mechanical integrity of a carbon nanotube/copper-based through-silicon via for 3D integrated circuits: a multi-scale modeling approach.

    Science.gov (United States)

    Awad, Ibrahim; Ladani, Leila

    2015-12-01

    Carbon nanotube (CNT)/copper (Cu) composite material is proposed to replace Cu-based through-silicon vias (TSVs) in micro-electronic packages. The proposed material is believed to offer extraordinary mechanical and electrical properties and the presence of CNTs in Cu is believed to overcome issues associated with miniaturization of Cu interconnects, such as electromigration. This study introduces a multi-scale modeling of the proposed TSV in order to evaluate its mechanical integrity under mechanical and thermo-mechanical loading conditions. Molecular dynamics (MD) simulation was used to determine CNT/Cu interface adhesion properties. A cohesive zone model (CZM) was found to be most appropriate to model the interface adhesion, and CZM parameters at the nanoscale were determined using MD simulation. CZM parameters were then used in the finite element analysis in order to understand the mechanical and thermo-mechanical behavior of composite TSV at micro-scale. From the results, CNT/Cu separation does not take place prior to plastic deformation of Cu in bending, and separation does not take place when standard thermal cycling is applied. Further investigation is recommended in order to alleviate the increased plastic deformation in Cu at the CNT/Cu interface in both loading conditions. PMID:26559788

  18. Toward transformational carbon capture systems

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States); Litynski, John T. [Office of Fossil Energy, U.S. Dept. of Energy, Washington DC (United States); Brickett, Lynn A. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States); Morreale, Bryan D. [National Energy Technology Laboratory, U.S. Dept. of Energy, Pittsburgh PA (United States)

    2015-10-28

    This paper will briefly review the history and current state of Carbon Capture and Storage (CCS) research and development and describe the technical barriers to carbon capture. it will argue forcefully for a new approach to R&D, which leverages both simulation and physical systems at the laboratory and pilot scales to more rapidly move the best technoogies forward, prune less advantageous approaches, and simultaneously develop materials and processes.

  19. 微波烧结制备碳酸化多孔羟基磷灰石纳米陶瓷%Preparation of Porous Carbonated Hydroxyapatite Nanoceramics Based on Microwave Sintering Approach

    Institute of Scientific and Technical Information of China (English)

    李波; 廖晓玲; 朱向东; 范红松; 张兴栋

    2011-01-01

    采用活性炭辅助微波烧结的方法制备多孔碳酸化磷酸钙纳米陶瓷。通过考察多孔陶瓷坯体在不同烧结温度的线收缩率和抗压强度得到合适的烧结温度。1000℃微波烧结得到多孔碳酸化磷酸钙纳米陶瓷:抗压强度约为2.5MPa,平均晶粒尺寸约为132nm,孔隙率约为75%。与常规陶瓷相比,该种陶瓷抗压强度相当、晶粒尺寸更小并且微观结构更均匀,并降低了烧结温度约100℃。结果表明:活性炭不仅有利于辅助磷酸钙陶瓷微波升温,还有利于引入碳酸根,为制备A型碳酸化羟基磷灰石纳米陶瓷提供了新思路。动物骨内植入的初步实验表明这种新型材料较常规材料具有更优的生物活性。%A microwave sintering method with activated carbon as embedding material was applied to prepare porous carbonated hydroxyapatite nanoceramics (CHA). By examining linear shrinkages and compressive strengths of samples at different temperatures, a suitable microwave sintering temperature was achieved. The compressive strength of CHA is about 2.5 MPa, the grain size is about 132 nm and porosity is about 75% at the microwave sintering temperature of 1 000 ℃. Compared with the samples prepared by con- ventional sintering method, the CHA bioceramics prepared by the proposed microwave sintering approach show a compressive strength similar to the conventional ones, and have smaller grain size, more uniform microstructure, and a sintering temperature as low as about 100 ℃. Results suggest that activated carbon not only preheats hydroxyapatite but also introduces carbonate groups to hydroxyapatite crystal, which provides a new research direction for the preparation of A-type CHA with a nanostructure. The in vivo tests on mongrel dogs show higher bioactivity of nano A-type CHA compared to general HA.

  20. Estimating Ring Strain Energies of Highly Substituted Cyclohexanes with the Semi-homodesmotic Approach: Why Substantial Ring Strain Exists for Nominally Tetrahedral Ring Carbon Atoms.

    Science.gov (United States)

    De Lio, Ashley M; Durfey, Bridget L; Gilbert, Thomas M

    2015-10-16

    Estimation of ring strain energies (RSEs) of substituted cyclohexanes c-C6H(x)R(12-x) (R = F, Cl, Me; x = 0, 2, 4, 8, 10, 12) using homodesmotic reaction methods gives implausible results for highly substituted cases, particularly, c-C6R12. Prior work suggests that this stems from poorly canceled interactions between substituents on the acyclic reference molecules. We apply here our semi-homodesmotic approach that minimizes use of acyclic references and ensures cancellation of intramolecular substituent interactions. The approach provides RSEs that are more consistent with chemical intuition, although they are higher than expected for "strain-free" cyclohexanes. The RSE for c-C6Me12 is predicted to be 11.9 kcal mol(-1). RSEs for halogenated rings rise significantly from 8-9 kcal mol(-1) for c-1,1,2,2-C6H8R4 to 44-50 kcal mol(-1) for c-C6R12 (R = F, Cl). The increase, and accompanying observation of larger RSEs for "adjacent CR2" systems, can be tied to increased bond distances in the rings upon progressive substitution. The sizable RSE for perchlorocyclohexane suggests that it may be susceptible to ring-opening reactions, a facet of its chemistry that is currently unexplored. PMID:26383035

  1. Evaluating the Influence of Pore Architecture and Initial Saturation on Wettability and Relative Permeability in Heterogeneous, Shallow-Shelf Carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Byrnes, Alan P.; Bhattacharya, Saibal; Victorine, John; Stalder, Ken

    2007-09-30

    Thin (3-40 ft thick), heterogeneous, limestone and dolomite reservoirs, deposited in shallow-shelf environments, represent a significant fraction of the reservoirs in the U.S. midcontinent and worldwide. In Kansas, reservoirs of the Arbuckle, Mississippian, and Lansing-Kansas City formations account for over 73% of the 6.3 BBO cumulative oil produced over the last century. For these reservoirs basic petrophysical properties (e.g., porosity, absolute permeability, capillary pressure, residual oil saturation to waterflood, resistivity, and relative permeability) vary significantly horizontally, vertically, and with scale of measurement. Many of these reservoirs produce from structures of less than 30-60 ft, and being located in the capillary pressure transition zone, exhibit vertically variable initial saturations and relative permeability properties. Rather than being simpler to model because of their small size, these reservoirs challenge characterization and simulation methodology and illustrate issues that are less apparent in larger reservoirs where transition zone effects are minor and most of the reservoir is at saturations near S{sub wirr}. These issues are further augmented by the presence of variable moldic porosity and possible intermediate to mixed wettability and the influence of these on capillary pressure and relative permeability. Understanding how capillary-pressure properties change with rock lithology and, in turn, within transition zones, and how relative permeability and residual oil saturation to waterflood change through the transition zone is critical to successful reservoir management and as advanced waterflood and improved and enhanced recovery methods are planned and implemented. Major aspects of the proposed study involve a series of tasks to measure data to reveal the nature of how wettability and drainage and imbibition oil-water relative permeability change with pore architecture and initial water saturation. Focus is placed on

  2. Southwest Regional Partnership on Carbon Sequestration Phase II

    Energy Technology Data Exchange (ETDEWEB)

    James Rutledge

    2011-02-01

    The Southwest Regional Partnership (SWP) on Carbon Sequestration designed and deployed a medium-scale field pilot test of geologic carbon dioxide (CO2) sequestration in the Aneth oil field. Greater Aneth oil field, Utah's largest oil producer, was discovered in 1956 and has produced over 455 million barrels of oil (72 million m3). Located in the Paradox Basin of southeastern Utah, Greater Aneth is a stratigraphic trap producing from the Pennsylvanian Paradox Formation. Because it represents an archetype oil field of the western U.S., Greater Aneth was selected as one of three geologic pilots to demonstrate combined enhanced oil recovery (EOR) and CO2 sequestration under the auspices of the SWP on Carbon Sequestration, sponsored by the U.S. Department of Energy. The pilot demonstration focuced on the western portion of the Aneth Unit as this area of the field was converted from waterflood production to CO2 EOR starting in late 2007. The Aneth Unit is in the northwestern part of the field and has produced 149 million barrels (24 million m3) of the estimated 450 million barrels (71.5 million m3) of the original oil in place - a 33% recovery rate. The large amount of remaining oil makes the Aneth Unit ideal to demonstrate both CO2 storage capacity and EOR by CO2 flooding. This report summarizes the geologic characterization research, the various field monitoring tests, and the development of a geologic model and numerical simulations conducted for the Aneth demonstration project. The Utah Geological Survey (UGS), with contributions from other Partners, evaluated how the surface and subsurface geology of the Aneth Unit demonstration site will affect sequestration operations and engineering strategies. The UGS-research for the project are summarized in Chapters 1 through 7, and includes (1) mapping the surface geology including stratigraphy, faulting, fractures, and deformation bands, (2) describing the local Jurassic and Cretaceous stratigraphy, (3) mapping the

  3. Carbon Management:A New Approach to the Governance of Saline Soils%碳管理:盐土治理的一种新思路

    Institute of Scientific and Technical Information of China (English)

    崔士友; 张蛟蛟

    2015-01-01

    Coastal shoal saline-alkali land is the main reserve land resource of Jiangsu Province which has a large population and relatively little arable land. The prerequisite of the exploitation and utilization of coastal shoal saline-alkali land is reducing salt content. The author summarized the research results of saline-alkali soils governance from the perspective of carbon management. Three technological options for the improvement were salt tolerant plants, agronomic techniques to improve SOC pool and the leaching of salts. The important agronomic techniques were manure, crop residues management, artificial forest establishment, agroforestry system, perennial grass and forages growth, nutrition integrated management and so on. At last, investigation strategies for the reclamation of saline-alkali land and salt tolerant crop plantation were briefly discussed in the paper.%江苏人多地少,沿海滩涂盐碱地是其主要的土地后备资源,滩涂盐碱地开发利用的前提是盐土的快速降盐.笔者从碳管理的角度综述了盐土治理方面的研究成果.盐土改良的3个技术措施为耐盐植物、改进土壤SOC库的农艺技术以及可溶性盐的淋溶,而重要的农艺技术包括粪肥、作物残茬管理、建立人工林、农林系统、多年生禾草与饲草、营养综合管理等.最后,笔者对江苏沿海滩涂盐土改良与耐盐作物研究策略作了简单的讨论.

  4. Approaches to Quantify Potential Contaminant Transport in the Lower Carbonate Aquifer from Underground Nuclear Testing at Yucca Flat, Nevada National Security Site, Nye County, Nevada - 12434

    International Nuclear Information System (INIS)

    Quantitative modeling of the potential for contaminant transport from sources associated with underground nuclear testing at Yucca Flat is an important part of the strategy to develop closure plans for the residual contamination. At Yucca Flat, the most significant groundwater resource that could potentially be impacted is the Lower Carbonate Aquifer (LCA), a regionally extensive aquifer that supplies a significant portion of the water demand at the Nevada National Security Site, formerly the Nevada Test Site. Developing and testing reasonable models of groundwater flow in this aquifer is an important precursor to performing subsequent contaminant transport modeling used to forecast contaminant boundaries at Yucca Flat that are used to identify potential use restriction and regulatory boundaries. A model of groundwater flow in the LCA at Yucca Flat has been developed. Uncertainty in this model, as well as other transport and source uncertainties, is being evaluated as part of the Underground Testing Area closure process. Several alternative flow models of the LCA in the Yucca Flat/Climax Mine CAU have been developed. These flow models are used in conjunction with contaminant transport models and source term models and models of contaminant transport from underground nuclear tests conducted in the overlying unsaturated and saturated alluvial and volcanic tuff rocks to evaluate possible contaminant migration in the LCA for the next 1,000 years. Assuming the flow and transport models are found adequate by NNSA/NSO and NDEP, the models will undergo a peer review. If the model is approved by NNSA/NSO and NDEP, it will be used to identify use restriction and regulatory boundaries at the start of the Corrective Action Decision Document Corrective Action Plan (CADD/CAP) phase of the Corrective Action Strategy. These initial boundaries may be revised at the time of the Closure Report phase of the Corrective Action Strategy. (authors)

  5. Soil organic carbon dynamics in wheat-maize cropping systems of north China: application of isotope approach to long-term experiments

    Science.gov (United States)

    Wang, J.; Wang, X.; Xu, M.; Zhang, W.

    2013-12-01

    Soil organic carbon (SOC) in agro-ecosystem is largely influencedby agricultural practices such as croppingand fertilization. However, quantifying the contributions of various crops has been lacking. Here, we applied isotopic approachto study SOC dynamics under wheat-maize rotation with variousfertilization treatments atthree long-term experiment sites innorth China. Three treatments were chosen: no fertilizer (control), chemical nitrogen-phosphorus-potassium (NPK) and NPK plus straw (NPKS).Soil samples were collected from0-20, 20-40, 40-60, 60-80 and 80-100cm after 13 and 20 years of treatment, and SOC and its stable 13C compositions were determined. Generally, SOC content significantly decreased with depths, from 8.2 ×1.4 g kg-1 (in 0-20 cm) to 3.3×1.0 g kg-1 (in 80-100 cm) across all treatments and sites. Soil δ13C values at all depths, treatments and sites ranged from -24.2‰ to -21.6‰, averaged -22.8‰, indicating that ~70% of SOC was derived from wheat and previous C3 plant, and ~30% from maize and previous C4 plant.Both SOC and soil δ13C were significantly affected by fertilization managements, especiallyin 0-40 cm where linear relationship occurred between SOC and estimated C input. Overall, the slop of the linear equation, i.e., conversion efficiency, was four times greater for wheat-derived C relative to that for maize residue C. Our study indicated that maize-derived C contributed less to C sequestration in wheat-maize rotation system of north China. Figure 1. Relationships between SOC stock (0-40 cm) and accumulated C input for wheat (C3), maize (C4) and total. Significance is marked with one (P < 0.05), two (P < 0.01) and three (P < 0.001) asterisks.

  6. Carbon budget of tropical forests in Southeast Asia and the effects of deforestation: an approach using a process-based model and field measurements

    Directory of Open Access Journals (Sweden)

    M. Adachi

    2011-03-01

    Full Text Available More reliable estimates of carbon (C stock within forest ecosystems and C emission induced by deforestation are urgently needed to mitigate the effects of emissions on climate change. A process-based terrestrial biogeochemical model (VISIT was applied to tropical primary forests of two types (a seasonal dry forest in Thailand and a rainforest in Malaysia and one agro-forest (an oil palm plantation in Malaysia to estimate the C budget of tropical ecosystems, including the impacts of land-use conversion, in Southeast Asia. Observations and VISIT model simulations indicated that the primary forests had high photosynthetic uptake: gross primary production was estimated at 31.5–35.5 t C ha−1 yr−1. In the VISIT model simulation, the rainforest had a higher total C stock (plant biomass and soil organic matter, 301.5 t C ha−1 than that in the seasonal dry forest (266.5 t C ha−1 in 2008. The VISIT model appropriately captured the impacts of disturbances such as deforestation and land-use conversions on the C budget. Results of sensitivity analysis implied that the ratio of remaining residual debris was a key parameter determining the soil C budget after deforestation events. The C stock of the oil palm plantation was about 46% of the rainforest's C at 30 yr following initiation of the plantation, when the ratio of remaining residual debris was assumed to be about 33%. These results show that adequate forest management is important for reducing C emission from soil and C budget of each ecosystem must be evaluated over a long term using both the model simulations and observations.

  7. Carbon budget of tropical forests in Southeast Asia and the effects of deforestation: approach from a process model and field measurements

    Science.gov (United States)

    Adachi, M.; Ito, A.; Ishida, A.; Kadir, W. R.; Ladpala, P.; Yamagata, Y.

    2010-12-01

    More reliable estimation of carbon (C) stock within forest ecosystems and C emission induced by deforestation is one of the most urgent tasks for model researchers. A process-based terrestrial biogeochemical model (VISIT) was applied to two types of tropical forests (a seasonal dry forest in Thailand and a moist forest in Malaysia) and one agro-forest (an oil palm plantation in Malaysia) to estimate C budget of tropical ecosystems including the impacts of land use conversion in Southeast Asia. Observation and VISIT model simulation indicated that the two types of tropical forest had a comparably high photosynthetic uptakes; gross primary productions were estimated as 32.2-37.6 t C ha-1 y-1. A rain forest had a higher total C stock (plant biomass and soil organic matter, 301.5 t C ha-1) than that in a seasonal dry forest (266.5 t C ha-1). The VISIT model appropriately captured the impacts of disturbance such as deforestation and land use conversions on C budget, and a sensitivity analysis implied that remaining ratios of abandoned debris would be a key parameter determining soil C budget after deforestation events. Although the model tended to overestimate oil palm biomass in comparison with field data, C stock of the oil palm plantation was about half of the forest C at 30 years following the oil palm plantation formation when the remaining rate of residual debris was about 34%. These results indicated that adequate forest management was important for reducing C emission from soil, and C budget at each ecosystem need evaluate over a long-term using model and observations.

  8. Small diameter carbon nanopipettes

    Science.gov (United States)

    Singhal, Riju; Bhattacharyya, Sayan; Orynbayeva, Zulfiya; Vitol, Elina; Friedman, Gary; Gogotsi, Yury

    2010-01-01

    Nanoscale multifunctional carbon probes facilitate cellular studies due to their small size, which makes it possible to interrogate organelles within living cells in a minimally invasive fashion. However, connecting nanotubes to macroscopic devices and constructing an integrated system for the purpose of fluid and electrical signal transfer is challenging, as is often the case with nanoscale components. We describe a non-catalytic chemical vapor deposition based method for batch fabrication of integrated multifunctional carbon nanopipettes (CNPs) with tip diameters much smaller (10-30 nm) than previously reported (200 nm and above) and approaching those observed for multiwalled carbon nanotubes. This eliminates the need for complicated attachment/assembly of nanotubes into nanofluidic devices. Variable tip geometries and structures were obtained by controlled deposition of carbon inside and outside quartz pipettes. We have shown that the capillary length and gas flow rate have a marked effect on the carbon deposition. This gives us a flexible protocol, useful for growing carbon layers of different thicknesses at selective locations on a glass pipette to yield a large variety of cellular probes in bulk quantities. The CNPs possess an open channel for fluid transfer with the carbon deposited inside at 875 °C behaving like an amorphous semiconductor. Vacuum annealing of the CNP tips at temperatures up to 2000 °C yields graphitic carbon structures with an increase in conductivity of two orders of magnitude. Penetration of the integrated carbon nanoprobes into cells was shown to produce minimal Ca2+ signals, fast recovery of basal Ca2+ levels and no adverse activation of the cellular metabolism during interrogation times as long as 0.5-1 h.

  9. Small diameter carbon nanopipettes

    International Nuclear Information System (INIS)

    Nanoscale multifunctional carbon probes facilitate cellular studies due to their small size, which makes it possible to interrogate organelles within living cells in a minimally invasive fashion. However, connecting nanotubes to macroscopic devices and constructing an integrated system for the purpose of fluid and electrical signal transfer is challenging, as is often the case with nanoscale components. We describe a non-catalytic chemical vapor deposition based method for batch fabrication of integrated multifunctional carbon nanopipettes (CNPs) with tip diameters much smaller (10-30 nm) than previously reported (200 nm and above) and approaching those observed for multiwalled carbon nanotubes. This eliminates the need for complicated attachment/assembly of nanotubes into nanofluidic devices. Variable tip geometries and structures were obtained by controlled deposition of carbon inside and outside quartz pipettes. We have shown that the capillary length and gas flow rate have a marked effect on the carbon deposition. This gives us a flexible protocol, useful for growing carbon layers of different thicknesses at selective locations on a glass pipette to yield a large variety of cellular probes in bulk quantities. The CNPs possess an open channel for fluid transfer with the carbon deposited inside at 875 deg. C behaving like an amorphous semiconductor. Vacuum annealing of the CNP tips at temperatures up to 2000 deg. C yields graphitic carbon structures with an increase in conductivity of two orders of magnitude. Penetration of the integrated carbon nanoprobes into cells was shown to produce minimal Ca2+ signals, fast recovery of basal Ca2+ levels and no adverse activation of the cellular metabolism during interrogation times as long as 0.5-1 h.

  10. A comparative study of multiple regression analysis and back propagation neural network approaches on plain carbon steel in submerged-arc welding

    Indian Academy of Sciences (India)

    ABHIJIT SARKAR; PRASENJIT DEY; R N RAI; SUBHAS CHANDRA SAHA

    2016-05-01

    Weld bead plays an important role in determining the quality of welding particularly in high heat input processes. This research paper presents the development of multiple regression analysis (MRA) and artificial neural network (ANN) models to predict weld bead geometry and HAZ width in submerged arcwelding process. Design of experiments is based on Taguchi’s L16 orthogonal array by varying wire feed rate,transverse speed and stick out to develop a multiple regression model, which has been checked for adequacy andsignificance. Also, ANN model was accomplished with the back propagation approach in MATLAB program to predict bead geometry and HAZ width. Finally, the results of two prediction models were compared and analyzed. It is found that the error related to the prediction of bead geometry and HAZ width is smaller in ANN than MRA.

  11. A review of the archaeological analogue approaches to predict the long-term corrosion behaviour of carbon steel overpack and reinforced concrete structures in the French disposal systems

    International Nuclear Information System (INIS)

    This paper gives a review of several years of research on archaeological analogues in order to predict the long term behaviour of the steel canisters or the reinforced concrete structures involved in disposal or interim storage of nuclear wastes in France. This article aims at showing the specific methodology, the complementariness with different other approaches and the complete integration of the research on analogues in the frame of research programs on long term prediction. Archaeological sites on which field measurement can be performed were referenced and described. A significant number of artefacts collected from these sites was selected for study. Detailed chemical and microstructural characterisation of the artefacts were undertaken by a combination of microbeam analytical techniques (μRaman, μXRD, μRaman spectroscopy,...). Hypotheses on the corrosion mechanisms were then tested using specific isotopic markers during re-corroding experiments on analogues. Specific parameters were measured, allowing crucial steps in modelling long-term corrosion of steel.

  12. Multimetallic Electrodeposition on Carbon Fibers

    Science.gov (United States)

    Böttger-Hiller, F.; Kleiber, J.; Böttger, T.; Lampke, T.

    2016-03-01

    Efficient lightweight design requires intelligent materials that meet versatile functions. One approach is to extend the range of properties of carbon fiber reinforced plastics (CFRP) by plating the fiber component. Electroplating leads to metalized layers on carbon fibers. Herein only cyanide-free electrolytes where used. Until now dendrite-free layers were only obtained using current densities below 1.0 A dm-2. In this work, dendrite-free tin and copper coatings were achieved by pre-metalizing the carbon fiber substrates. Furthermore, applying a combination of two metals with different sized thermal expansion coefficient lead to a bimetallic coating on carbon fiber rovings, which show an actuatory effect.

  13. Priming of soil carbon decomposition in two Inner Mongolia grassland soils following sheep dung addition: a study using ¹³C natural abundance approach.

    Directory of Open Access Journals (Sweden)

    Xiuzhi Ma

    Full Text Available To investigate the effect of sheep dung on soil carbon (C sequestration, a 152 days incubation experiment was conducted with soils from two different Inner Mongolian grasslands, i.e. a Leymus chinensis dominated grassland representing the climax community (2.1% organic matter content and a heavily degraded Artemisia frigida dominated community (1.3% organic matter content. Dung was collected from sheep either fed on L. chinensis (C3 plant with δ¹³C = -26.8‰; dung δ¹³C = -26.2‰ or Cleistogenes squarrosa (C₄ plant with δ¹³C = -14.6‰; dung δ¹³C = -15.7‰. Fresh C₃ and C₄ sheep dung was mixed with the two grassland soils and incubated under controlled conditions for analysis of ¹³C-CO₂ emissions. Soil samples were taken at days 17, 43, 86, 127 and 152 after sheep dung addition to detect the δ¹³C signal in soil and dung components. Analysis revealed that 16.9% and 16.6% of the sheep dung C had decomposed, of which 3.5% and 2.8% was sequestrated in the soils of L. chinensis and A. frigida grasslands, respectively, while the remaining decomposed sheep dung was emitted as CO₂. The cumulative amounts of C respired from dung treated soils during 152 days were 7-8 times higher than in the un-amended controls. In both grassland soils, ca. 60% of the evolved CO₂ originated from the decomposing sheep dung and 40% from the native soil C. Priming effects of soil C decomposition were observed in both soils, i.e. 1.4 g and 1.6 g additional soil C kg⁻¹ dry soil had been emitted as CO₂ for the L. chinensis and A. frigida soils, respectively. Hence, the net C losses from L. chinensis and A. frigida soils were 0.6 g and 0.9 g C kg⁻¹ soil, which was 2.6% and 7.0% of the total C in L. chinensis and A. frigida grasslands soils, respectively. Our results suggest that grazing of degraded Inner Mongolian pastures may cause a net soil C loss due to the positive priming effect, thereby accelerating soil

  14. A statistical approach to quantify uncertainty in carbon monoxide measurements at the Izaña global GAW station: 2008–2011

    Directory of Open Access Journals (Sweden)

    A. J. Gomez-Pelaez

    2013-03-01

    Full Text Available Atmospheric CO in situ measurements are carried out at the Izaña (Tenerife global GAW (Global Atmosphere Watch Programme of the World Meteorological Organization – WMO mountain station using a Reduction Gas Analyser (RGA. In situ measurements at Izaña are representative of the subtropical Northeast Atlantic free troposphere, especially during nighttime. We present the measurement system configuration, the response function, the calibration scheme, the data processing, the Izaña 2008–2011 CO nocturnal time series, and the mean diurnal cycle by months. We have developed a rigorous uncertainty analysis for carbon monoxide measurements carried out at the Izaña station, which could be applied to other GAW stations. We determine the combined standard measurement uncertainty taking into consideration four contributing components: uncertainty of the WMO standard gases interpolated over the range of measurement, the uncertainty that takes into account the agreement between the standard gases and the response function used, the uncertainty due to the repeatability of the injections, and the propagated uncertainty related to the temporal consistency of the response function parameters (which also takes into account the covariance between the parameters. The mean value of the combined standard uncertainty decreased significantly after March 2009, from 2.37 nmol mol−1 to 1.66 nmol mol−1, due to improvements in the measurement system. A fifth type of uncertainty we call representation uncertainty is considered when some of the data necessary to compute the temporal mean are absent. Any computed mean has also a propagated uncertainty arising from the uncertainties of the data used to compute the mean. The law of propagation depends on the type of uncertainty component (random or systematic. In situ hourly means are compared with simultaneous and collocated NOAA flask samples. The uncertainty of the differences is computed and used to determine

  15. Carbon budget of tropical forests in Southeast Asia and the effects of deforestation: an approach using a process-based model and field measurements

    Directory of Open Access Journals (Sweden)

    M. Adachi

    2011-09-01

    Full Text Available More reliable estimates of the carbon (C stock within forest ecosystems and C emission induced by deforestation are urgently needed to mitigate the effects of emissions on climate change. A process-based terrestrial biogeochemical model (VISIT was applied to tropical primary forests of two types (a seasonal dry forest in Thailand and a rainforest in Malaysia and one agro-forest (an oil palm plantation in Malaysia to estimate the C budget of tropical ecosystems in Southeast Asia, including the impacts of land-use conversion. The observed aboveground biomass in the seasonal dry tropical forest in Thailand (226.3 t C ha−1 and the rainforest in Malaysia (201.5 t C ha−1 indicate that tropical forests of Southeast Asia are among the most C-abundant ecosystems in the world. The model simulation results in rainforests were consistent with field data, except for the NEP, however, the VISIT model tended to underestimate C budget and stock in the seasonal dry tropical forest. The gross primary production (GPP based on field observations ranged from 32.0 to 39.6 t C ha−1 yr−1 in the two primary forests, whereas the model slightly underestimated GPP (26.5–34.5 t C ha−1 yr−1. The VISIT model appropriately captured the impacts of disturbances such as deforestation and land-use conversions on the C budget. Results of sensitivity analysis showed that the proportion of remaining residual debris was a key parameter determining the soil C budget after the deforestation event. According to the model simulation, the total C stock (total biomass and soil C of the oil palm plantation was about 35% of the rainforest's C stock at 30 yr following initiation of the plantation. However, there were few field data of C budget and stock, especially in oil palm plantation. The C budget of each ecosystem must be evaluated over the long term using both the model simulations and observations to

  16. Carbon budget of tropical forests in Southeast Asia and the effects of deforestation: an approach using a process-based model and field measurements

    Science.gov (United States)

    Adachi, M.; Ito, A.; Ishida, A.; Kadir, W. R.; Ladpala, P.; Yamagata, Y.

    2011-09-01

    More reliable estimates of the carbon (C) stock within forest ecosystems and C emission induced by deforestation are urgently needed to mitigate the effects of emissions on climate change. A process-based terrestrial biogeochemical model (VISIT) was applied to tropical primary forests of two types (a seasonal dry forest in Thailand and a rainforest in Malaysia) and one agro-forest (an oil palm plantation in Malaysia) to estimate the C budget of tropical ecosystems in Southeast Asia, including the impacts of land-use conversion. The observed aboveground biomass in the seasonal dry tropical forest in Thailand (226.3 t C ha-1) and the rainforest in Malaysia (201.5 t C ha-1) indicate that tropical forests of Southeast Asia are among the most C-abundant ecosystems in the world. The model simulation results in rainforests were consistent with field data, except for the NEP, however, the VISIT model tended to underestimate C budget and stock in the seasonal dry tropical forest. The gross primary production (GPP) based on field observations ranged from 32.0 to 39.6 t C ha-1 yr-1 in the two primary forests, whereas the model slightly underestimated GPP (26.5-34.5 t C ha-1 yr-1). The VISIT model appropriately captured the impacts of disturbances such as deforestation and land-use conversions on the C budget. Results of sensitivity analysis showed that the proportion of remaining residual debris was a key parameter determining the soil C budget after the deforestation event. According to the model simulation, the total C stock (total biomass and soil C) of the oil palm plantation was about 35% of the rainforest's C stock at 30 yr following initiation of the plantation. However, there were few field data of C budget and stock, especially in oil palm plantation. The C budget of each ecosystem must be evaluated over the long term using both the model simulations and observations to understand the effects of climate and land-use conversion on C budgets in tropical forest

  17. 碳排放权市场结构相依特征研究:规则藤方法%Dependence Structure of Carbon Emission Markets:Regular Vine Approach

    Institute of Scientific and Technical Information of China (English)

    胡根华; 吴恒煜; 邱甲贤

    2015-01-01

    process,ECP)混合方法的拟合优度检验,并基于Bootstrap方法,以Cramer von Mises( CvM)检验统计量作为度量测度,来对模型进行拟合优度的检验。研究发现,构建的规则藤Copula模型能够较好地捕捉碳排放权市场之间的相依结构。这一研究结果,为准确探讨碳排放权交易市场之间、碳排放权交易市场与其它资本市场之间套期保值策略提供了一定的参考意义,也有利于提高碳排放权市场产品定价的准确度。%Formation of the carbon emission trading market is a valuable approach to deal with the global warming problems based on economic theory, which aims at the development of a low-carbon economy. In the primary market of the European Union emission trading system, the carbon emission trading market becomes an important emerging market where the European Union Allowance ( EUA) is taken as the main object of the market transaction. With the development of the carbon emission trading market, its capitalization gradually deepens, the financial properties significantly increase and the market becomes integrated into the system of the international capital markets. Due to its similarity to other capital markets, a complex non-linear correlation exists in the carbon emission trading market, and the copula functions can be used to capture the characteristics of the dependence structure. Therefore, the paper chose the data on daily price series of EUA futures, assuming the series of innovations follows the Student’ s t-distribution, filtered the adjusted log-returns of EUA futures using the ARMA-GARCH model, and estimated the parameters in the model, obtained the series of the residuals and standardized them. Then, it took the coefficients of the Kendall’ s tau as the weights of the trees in the vine structure, constructed a feasible regular vine copula model by using the sequential selection approach based on the maximum spanning tree algorithm, and estimated the parameters by

  18. From Carbon Nanotube Crystals to Carbon Nanotube Flowers

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhengjun; ZHAO Ye; ZHOU Ya

    2005-01-01

    We have investigated the very initial deposition stages of chemical vapor deposition (CVD) with ferrocene (Fe(C5H5)2) and xylene (C8H10) for growing carbon nanotubes, and made clear that the mechanism for the self-organization behaviors of nanotubes at different growth stages by this approach. For instance, the organization of nanotubes into flower-like structures at prolonged deposition is developed from the crystal-like structures formed at early growth stages, both of which are closely related to and determined by the very initial deposition stages of this CVD approach. Based on this approach, ways have been established to build up different architectures of carbon nanotubes, by controlling the initial deposition stages of the CVD process, with which we have realized the selective growth of self-organized carbon nanotube structures. This study provides a new idea for growing carbon nanotube architectures by CVD.

  19. Horizontal carbon nanotube alignment.

    Science.gov (United States)

    Cole, Matthew T; Cientanni, Vito; Milne, William I

    2016-09-21

    The production of horizontally aligned carbon nanotubes offers a rapid means of realizing a myriad of self-assembled near-atom-scale technologies - from novel photonic crystals to nanoscale transistors. The ability to reproducibly align anisotropic nanostructures has huge technological value. Here we review the present state-of-the-art in horizontal carbon nanotube alignment. For both in and ex situ approaches, we quantitatively assess the reported linear packing densities alongside the degree of alignment possible for each of these core methodologies. PMID:27546174

  20. Carbon cycle makeover

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Kump, Lee R.

    2013-01-01

    remaining in sediments after respiration leave a residual of oxygen in the atmosphere. The source of oxygen to the atmosphere represented by organic matter burial is balanced by oxygen sinks associated with rock weathering and chemical reaction with volcanic gases. This is the long-term carbon and oxygen...... geochemical cycle. But Earth is an old planet, and oxygen levels have changed through time (2). On page 540 of this issue, Schrag et al. (3) challenge the most commonly used geochemical approach to assess long-term changes in the coupled oxygen and carbon cycles....

  1. Porous carbons

    Indian Academy of Sciences (India)

    Satish M Manocha

    2003-02-01

    Carbon in dense as well as porous solid form is used in a variety of applications. Activated porous carbons are made through pyrolysis and activation of carbonaceous natural as well as synthetic precursors. Pyrolysed woods replicate the structure of original wood but as such possess very low surface areas and poor adsorption capacities. On activation, these exhibit increased adsorption volumes of 0.5–0.8 cm3 /gm and surface areas of 700–1800 m2 /gm depending on activation conditions, whether physical or chemical. Former carbons possess mixed pore size distribution while chemically activated carbons predominantly possess micropores. Thus, these carbons can be used for adsorption of wide distributions of molecules from gas to liquid. The molecular adsorption within the pores is due to single layer or multilayer molecule deposition at the pore walls and hence results in different types of adsorption isotherm. On the other hand, activated carbon fibres with controlled microporous structure and surface area in the range of 2500 m2 /gm can be developed by controlled pyrolysis and physical activation of amorphous carbon fibres. Active carbon fibres with unmatchable pore structure and surface characteristics are present and futuristic porous materials for a number of applications from pollution control to energy storage.

  2. CARBON DIOXIDE FIXATION.

    Energy Technology Data Exchange (ETDEWEB)

    FUJITA,E.

    2000-01-12

    Solar carbon dioxide fixation offers the possibility of a renewable source of chemicals and fuels in the future. Its realization rests on future advances in the efficiency of solar energy collection and development of suitable catalysts for CO{sub 2} conversion. Recent achievements in the efficiency of solar energy conversion and in catalysis suggest that this approach holds a great deal of promise for contributing to future needs for fuels and chemicals.

  3. Improving Carbon Fixation Pathways

    OpenAIRE

    Ducat, Daniel C.; Silver, Pamela A

    2012-01-01

    A recent resurgence in basic and applied research on photosynthesis has been driven in part by recognition that fulfilling future food and energy requirements will necessitate improvements in crop carbon-fixation efficiencies. Photosynthesis in traditional terrestrial crops is being reexamined in light of molecular strategies employed by photosynthetic microbes to enhance the activity of the Calvin cycle. Synthetic biology is well-situated to provide original approaches for compartmentalizing...

  4. Calcium Carbonate

    Science.gov (United States)

    ... before being swallowed; do not swallow them whole. Drink a full glass of water after taking either the regular or chewable tablets or capsules. Some liquid forms of calcium carbonate must be shaken well before use.Do not ...

  5. Carbon Stars

    Indian Academy of Sciences (India)

    T. Lloyd Evans

    2010-12-01

    In this paper, the present state of knowledge of the carbon stars is discussed. Particular attention is given to issues of classification, evolution, variability, populations in our own and other galaxies, and circumstellar material.

  6. Hyphenation of a EC / OC thermal-optical carbon analyzer to photo ionization time-of-flight mass spectrometry: a new off-line aerosol mass spectrometric approach for characterization of primary and secondary particulate matter

    Directory of Open Access Journals (Sweden)

    J. Diab

    2015-01-01

    Full Text Available Source apportionment and exposure of primary and secondary aerosols remains a challenging research field. In particular, the organic composition of primary particles and the formation mechanism of secondary organic aerosols (SOA warrant further investigations. Progress in this field is strongly connected to the development of novel analytical techniques. In this study an off-line aerosol mass spectrometric technique based on filter samples, a hyphenated thermal/optical analyzer-photo ionization time of flight mass spectrometer (PI-TOFMS system, was developed. The approach extends the capability of the widely used PM carbon analysis (for elemental/organic carbon (EC / OC by enabling the investigation of evolved gaseous species with soft and selective (resonance enhanced multiphoton ionization, REMPI and non-selective photo ionization (single photon ionization, SPI techniques. SPI was tuned to be medium soft to achieve comparability with results obtained by electron ionization (EI aerosol mass spectrometer (AMS. Different PM samples including wood combustion emission samples, smog chamber samples from the reaction of ozone with different SOA precursors, and ambient samples taken at Ispra, Italy in winter as well as in summer were tested. The EC / OC-PI-TOFMS technique increases the understanding of the processes during the thermal/optical analysis and identifies marker substances for the source apportionment. Composition of oligomeric or polymeric species present in PM can be investigated by the analysis of the thermally breakdown products. In case of wood combustion, in addition to the well-known markers at m/z ratios of 60 and 73, two new characteristic masses (m/z 70 and 98 have been revealed as potentially linked to biomass burning. All four masses were also the dominant signals in an ambient sample taken in winter time in Ispra, Italy, confirming the finding that wood burning for residential heating is a major source for particulate matter

  7. Activated Carbon, Carbon Nanofiber and Carbon Nanotube Supported Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Guaiacol

    Directory of Open Access Journals (Sweden)

    Eduardo Santillan-Jimenez

    2015-03-01

    Full Text Available Molybdenum carbide was supported on three types of carbon support—activated carbon; multi-walled carbon nanotubes; and carbon nanofibers—using ammonium molybdate and molybdic acid as Mo precursors. The use of activated carbon as support afforded an X-ray amorphous Mo phase, whereas crystalline molybdenum carbide phases were obtained on carbon nanofibers and, in some cases, on carbon nanotubes. When the resulting catalysts were tested in the hydrodeoxygenation (HDO of guaiacol in dodecane, catechol and phenol were obtained as the main products, although in some instances significant amounts of cyclohexane were produced. The observation of catechol in all reaction mixtures suggests that guaiacol was converted into phenol via sequential demethylation and HDO, although the simultaneous occurrence of a direct demethoxylation pathway cannot be discounted. Catalysts based on carbon nanofibers generally afforded the highest yields of phenol; notably, the only crystalline phase detected in these samples was Mo2C or Mo2C-ζ, suggesting that crystalline Mo2C is particularly selective to phenol. At 350 °C, carbon nanofiber supported Mo2C afforded near quantitative guaiacol conversion, the selectivity to phenol approaching 50%. When guaiacol HDO was performed in the presence of acetic acid and furfural, guaiacol conversion decreased, although the selectivity to both catechol and phenol was increased.

  8. Carbon Nanotube Purification and Functionalization

    Science.gov (United States)

    Lebron, Marisabel; Mintz, Eric; Smalley, Richard E.; Meador, Michael A.

    2003-01-01

    Carbon nanotubes have the potential to significantly enhance the mechanical, thermal, and electrical properties of polymers. However, dispersion of carbon nanotubes in a polymer matrix is hindered by the electrostatic forces that cause them to agglomerate. Chemical modification of the nanotubes is necessary to minimize these electrostatic forces and promote adhesion between the nanotubes and the polymer matrix. In a collaborative research program between Clark Atlanta University, Rice University, and NASA Glenn Research Center several approaches are being explored to chemically modify carbon nanotubes. The results of this research will be presented.

  9. Liberating energy from carbon introduction to decarbonization

    CERN Document Server

    Muradov, Nazim

    2014-01-01

    Liberating Energy from Carbon analyzes energy options in a carbon-constrained world. Major strategies and pathways to decarbonizing the carbon-intensive economy are laid out with a special emphasis on the prospects of achieving low-risk atmospheric CO2 levels. The opportunities and challenges in developing and bringing to market novel low and zero-carbon technologies are highlighted from technical, economic and environmental viewpoints. This book takes a unique approach by treating carbon in a holistic manner?tracking its complete transformation chain from fossil fuel sources to the unique pro

  10. Multiscale carbon nanotube-carbon fiber reinforcement for advanced epoxy composites.

    Science.gov (United States)

    Bekyarova, E; Thostenson, E T; Yu, A; Kim, H; Gao, J; Tang, J; Hahn, H T; Chou, T-W; Itkis, M E; Haddon, R C

    2007-03-27

    We report an approach to the development of advanced structural composites based on engineered multiscale carbon nanotube-carbon fiber reinforcement. Electrophoresis was utilized for the selective deposition of multi- and single-walled carbon nanotubes (CNTs) on woven carbon fabric. The CNT-coated carbon fabric panels were subsequently infiltrated with epoxy resin using vacuum-assisted resin transfer molding (VARTM) to fabricate multiscale hybrid composites in which the nanotubes were completely integrated into the fiber bundles and reinforced the matrix-rich regions. The carbon nanotube/carbon fabric/epoxy composites showed approximately 30% enhancement of the interlaminar shear strength as compared to that of carbon fiber/epoxy composites without carbon nanotubes and demonstrate significantly improved out-of-plane electrical conductivity. PMID:17326671

  11. Digital carbonate rock physics

    Science.gov (United States)

    Saenger, Erik H.; Vialle, Stephanie; Lebedev, Maxim; Uribe, David; Osorno, Maria; Duda, Mandy; Steeb, Holger

    2016-08-01

    Modern estimation of rock properties combines imaging with advanced numerical simulations, an approach known as digital rock physics (DRP). In this paper we suggest a specific segmentation procedure of X-ray micro-computed tomography data with two different resolutions in the µm range for two sets of carbonate rock samples. These carbonates were already characterized in detail in a previous laboratory study which we complement with nanoindentation experiments (for local elastic properties). In a first step a non-local mean filter is applied to the raw image data. We then apply different thresholds to identify pores and solid phases. Because of a non-neglectable amount of unresolved microporosity (micritic phase) we also define intermediate threshold values for distinct phases. Based on this segmentation we determine porosity-dependent values for effective P- and S-wave velocities as well as for the intrinsic permeability. For effective velocities we confirm an observed two-phase trend reported in another study using a different carbonate data set. As an upscaling approach we use this two-phase trend as an effective medium approach to estimate the porosity-dependent elastic properties of the micritic phase for the low-resolution images. The porosity measured in the laboratory is then used to predict the effective rock properties from the observed trends for a comparison with experimental data. The two-phase trend can be regarded as an upper bound for elastic properties; the use of the two-phase trend for low-resolution images led to a good estimate for a lower bound of effective elastic properties. Anisotropy is observed for some of the considered subvolumes, but seems to be insignificant for the analysed rocks at the DRP scale. Because of the complexity of carbonates we suggest using DRP as a complementary tool for rock characterization in addition to classical experimental methods.

  12. Dilute Surfactant Methods for Carbonate Formations

    Energy Technology Data Exchange (ETDEWEB)

    Kishore K. Mohanty

    2006-02-01

    There are many fractured carbonate reservoirs in US (and the world) with light oil. Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). The process of using dilute anionic surfactants in alkaline solutions has been investigated in this work for oil recovery from fractured oil-wet carbonate reservoirs both experimentally and numerically. This process is a surfactant-aided gravity drainage where surfactant diffuses into the matrix, lowers IFT and contact angle, which decrease capillary pressure and increase oil relative permeability enabling gravity to drain the oil up. Anionic surfactants have been identified which at dilute concentration of 0.05 wt% and optimal salinity can lower the interfacial tension and change the wettability of the calcite surface to intermediate/water-wet condition as well or better than the cationic surfactant DTAB with a West Texas crude oil. The force of adhesion in AFM of oil-wet regions changes after anionic surfactant treatment to values similar to those of water-wet regions. The AFM topography images showed that the oil-wetting material was removed from the surface by the anionic surfactant treatment. Adsorption studies indicate that the extent of adsorption for anionic surfactants on calcite minerals decreases with increase in pH and with decrease in salinity. Surfactant adsorption can be minimized in the presence of Na{sub 2}CO{sub 3}. Laboratory-scale surfactant brine imbibition experiments give high oil recovery (20-42% OOIP in 50 days; up to 60% in 200 days) for initially oil-wet cores through wettability alteration and IFT reduction. Small (<10%) initial gas saturation does not affect significantly the rate of oil recovery in the imbibition process, but larger gas saturation decreases the oil recovery rate. As the core permeability decreases, the rate of oil recovery reduces

  13. The NASA Carbon Monitoring System

    Science.gov (United States)

    Hurtt, G. C.

    2015-12-01

    Greenhouse gas emission inventories, forest carbon sequestration programs (e.g., Reducing Emissions from Deforestation and Forest Degradation (REDD and REDD+), cap-and-trade systems, self-reporting programs, and their associated monitoring, reporting and verification (MRV) frameworks depend upon data that are accurate, systematic, practical, and transparent. A sustained, observationally-driven carbon monitoring system using remote sensing data has the potential to significantly improve the relevant carbon cycle information base for the U.S. and world. Initiated in 2010, NASA's Carbon Monitoring System (CMS) project is prototyping and conducting pilot studies to evaluate technological approaches and methodologies to meet carbon monitoring and reporting requirements for multiple users and over multiple scales of interest. NASA's approach emphasizes exploitation of the satellite remote sensing resources, computational capabilities, scientific knowledge, airborne science capabilities, and end-to-end system expertise that are major strengths of the NASA Earth Science program. Through user engagement activities, the NASA CMS project is taking specific actions to be responsive to the needs of stakeholders working to improve carbon MRV frameworks. The first phase of NASA CMS projects focused on developing products for U.S. biomass/carbon stocks and global carbon fluxes, and on scoping studies to identify stakeholders and explore other potential carbon products. The second phase built upon these initial efforts, with a large expansion in prototyping activities across a diversity of systems, scales, and regions, including research focused on prototype MRV systems and utilization of COTS technologies. Priorities for the future include: 1) utilizing future satellite sensors, 2) prototyping with commercial off-the-shelf technology, 3) expanding the range of prototyping activities, 4) rigorous evaluation, uncertainty quantification, and error characterization, 5) stakeholder

  14. Carbon capture using wastes: A review

    OpenAIRE

    Gunning, Peter; Hills, Colin; Araizi, Paris; Maries , Alan; Wray, David

    2014-01-01

    Potential key strategies for the management of anthropogenic CO2 emissions include mineral carbonation and storage in oil wells and in the oceans. In Europe, a large-scale demonstration of carbon capture and storage (CCS) has recently been given the go-ahead, and the application of mineral carbonation technology (MCT) to serpentine and olive-type minerals. Although less controversial in its approach, MCT involves intensive pre-treatment of the mineral feedstock, and a consequent high sequestr...

  15. Carbon neutron star atmospheres

    CERN Document Server

    Suleimanov, V F; Pavlov, G G; Werner, K

    2013-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in chemical composition of their atmospheres. For example, atmospheres of thermally - emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in CasA, a pure carbon atmosphere has recently been suggested by Ho & Heinke (2009). To test such a composition for other similar sources, a publicly available detailed grid of carbon model atmosphere spectra is needed. We have computed such a grid using the standard LTE approximation and assuming that the magnetic field does not exceed 10^8 G. The opacities and pressure ionization effects are calculated using the Opacity Project approach. We describe the properties of our models and investigate the impact of the adopted assumptions and approximations on the emergent spectra.

  16. Determination of Chemical Bond of Tetrahedral Amorphous Carbon Films by Ellipsometry Approach%椭偏法表征四面体非晶碳薄膜的化学键结构

    Institute of Scientific and Technical Information of China (English)

    李晓伟; 周毅; 孙丽丽; 汪爱英

    2012-01-01

    Tetrahedral amorphous carbon (ta-C) films under different substrate negative bias are prepared by a home developed filtered cathodic vacuum arc (FCVA) technology with double bend shape. The film thickness is measured by a combined spectrophotometry and spectroscopic ellipsometry (SE) approach; the chemical bonds including sp2C and sp3C are gained by the fitted ellipsometry method. Furthermore,the accuracy of ellipsometry results is evaluated by comparing with those of X-ray photoelectron spectroscopy (XPS) and Raman spectra. The results indicate that the minimum thickness of ta-C film of 33. 9 nm is obtained when the bias voltage is -100 V; with the increase of bias voltage,the optical gaps and the content of sp3C atomic bond decrease,while the sp2C content increases correspondingly. By comparison with the results of XPS and Raman spectra,it is found that when the optical constants of sp2C model are represented by the glassy carbon and the fitting wavelength ranges are chosen from 250 to 1700 nm,the best fitting result of atomic bonds of ta-C films can be deduced by the ellipsometry method. Therefore,it could be said that the elliposometry method is a quite promising method to characterize the atomic bonds of ta-C films including sp2C and sp3C,as a new nondestructive,fast,quantitative and easy way.%采用自主研制的双弯曲磁过滤阴极真空电弧(FCVA)技术,在不同衬底负偏压下制备了四面体非晶碳(ta-C)薄膜.通过分光光度计和椭偏(SE)联用技术精确测量了薄膜厚度,重点采用椭偏法对不同偏压下制备的ta-C薄膜sp3C键和sp2C键结构进行了拟合表征,并与X射线光电子能谱(XPS)和拉曼光谱的实验结果相对比,分析了非晶碳结构的椭偏拟合新方法可靠性.结果表明,在-100 V偏压时薄膜厚度最小,为33.9 nm;随着偏压的增加,薄膜中的sp2C含量增加,sp3C含量减小,光学带隙下降.对比结果发现,椭偏法作为一种无损、简易、快速的表征

  17. Optimal decisions of countries with carbon tax and carbon tariff

    Directory of Open Access Journals (Sweden)

    Yumei Hou

    2015-05-01

    Full Text Available Purpose: Reducing carbon emission has been the core problem of controlling global warming and climate deterioration recently. This paper focuses on the optimal carbon taxation policy levied by countries and the impact on firms’ optimal production decisions. Design/methodology/approach: This paper uses a two-stage game theory model to analyze the impact of carbon tariff and tax. Numerical simulation is used to supplement the theoretical analysis. Findings: Results derived from the paper indicate that the demand in an unstable market is significantly affected by environmental damage level. Carbon tariff is a policy-oriented tax while the carbon tax is a market-oriented one. Comprehensive carbon taxation policy benefit developed countries and basic policy is more suitable for developing countries. Research limitations/implications: In this research, we do not consider random demand and asymmetric information, which may not well suited the reality. Originality/value: This work provides a different perspective in analyzing the impact of carbon tax and tariff. It is the first study to consider two consuming market and the strategic game between two countries. Different international status of countries considered in the paper is also a unique point.

  18. Assessing carbon lock-in

    International Nuclear Information System (INIS)

    The term ‘carbon lock-in’ refers to the tendency for certain carbon-intensive technological systems to persist over time, ‘locking out’ lower-carbon alternatives, and owing to a combination of linked technical, economic, and institutional factors. These technologies may be costly to build, but relatively inexpensive to operate and, over time, they reinforce political, market, and social factors that make it difficult to move away from, or ‘unlock’ them. As a result, by investing in assets prone to lock-in, planners and investors restrict future flexibility and increase the costs of achieving agreed climate protection goals. Here, we develop a straight-forward approach to assess the speed, strength, and scale of carbon lock-in for major energy-consuming assets in the power, buildings, industry, and transport sectors. We pilot the approach at the global level, finding that carbon lock-in is greatest, globally, for coal power plants, gas power plants, and oil-based vehicles. The approach can be readily applied at the national or regional scale, and may be of particular relevance to policymakers interested in enhancing flexibility in their jurisdictions for deeper emissions cuts in the future, and therefore in limiting the future costs associated with ‘stranded assets’. (letter)

  19. Cascade enzymatic reactions for efficient carbon sequestration.

    Science.gov (United States)

    Xia, Shunxiang; Zhao, Xueyan; Frigo-Vaz, Benjamin; Zheng, Wenyun; Kim, Jungbae; Wang, Ping

    2015-04-01

    Thermochemical processes developed for carbon capture and storage (CCS) offer high carbon capture capacities, but are generally hampered by low energy efficiency. Reversible cascade enzyme reactions are examined in this work for energy-efficient carbon sequestration. By integrating the reactions of two key enzymes of RTCA cycle, isocitrate dehydrogenase and aconitase, we demonstrate that intensified carbon capture can be realized through such cascade enzymatic reactions. Experiments show that enhanced thermodynamic driving force for carbon conversion can be attained via pH control under ambient conditions, and that the cascade reactions have the potential to capture 0.5 mol carbon at pH 6 for each mole of substrate applied. Overall it manifests that the carbon capture capacity of biocatalytic reactions, in addition to be energy efficient, can also be ultimately intensified to approach those realized with chemical absorbents such as MEA. PMID:25708541

  20. Environmental economics: Optimal carbon tax doubled

    Science.gov (United States)

    Warren, Rachel

    2014-07-01

    Cost-benefit analysis and risk assessment approaches inform global climate change mitigation policy-making processes. Now, a development in the former shows that optimal carbon tax levels have previously been underestimated by a factor of two.

  1. Assessing the Low Carbon Mode for Tourism Regions Based on an AN P Approach%基于ANP法的低碳旅游景区评估模型

    Institute of Scientific and Technical Information of China (English)

    赵金凌; 高峻

    2011-01-01

    在全球气候变迁的趋势下,低碳成为很多行业包括旅游业发展的方向,低碳旅游逐渐成为保护资源和环境的新方式.本研究旨在总结低碳小区、低碳建筑、低碳产业的研究经验与成果,提出低碳旅游景区评估模型.主要采用方法是国际上解决类似问题常用的ANP方法,具体步骤为:首先依据相关文献归纳和低碳小区、低碳城市、低碳旅游区案例分析,提出低碳旅游景区评估指标;然后访谈5位低碳建筑、景观生态、资源能源、旅游环境、旅游规划领域专家,并从低碳设计、能源节约、水资源节约、生态保护四个方面归纳总结低碳旅游区的评佑指标,请专家采用ANP成对比较方法对低碳旅游区优先等级进行评价筛选;根据专家评选结果,用super decision软件进行指标权重值评估;最后进行一致性检验.研究成果期望能为低碳旅游区规划设计提供参考,为旅游及相关管理部门提供比较不同景区的碳排水平的理论方法,为碳排放较高景区提供调整建议;希望能为未来研究低碳经济评估指标提供案例.%A low carbon index for tourism regions would make it possible to measure progress towards a low carbon tourism region and support three important aspects of low carbon development: formulating policies for low carbon tourism regions and evaluating global impacts on the regions; enhancing dialogue and exchange of the best practice among tourism regions around the world; comparing development paths of various tourism regions and determining the gap between their current models so as to achieve a low carbon tourism. To that end, a commonly used index that can measure tourism region' s progress towards a low carbon mode is needed. The low carbon tourism region evaluation index is based on the concept of carbon budget, accounting for the ecological limits for global CO2 emissions in order to mitigate adverse effects resulting from climate

  2. Modelling Sublimation of Carbon Dioxide

    Science.gov (United States)

    Winkel, Brian

    2012-01-01

    In this article, the author reports results in their efforts to model sublimation of carbon dioxide and the associated kinetics order and parameter estimation issues in their model. They have offered the reader two sets of data and several approaches to determine the rate of sublimation of a piece of solid dry ice. They presented several models…

  3. Attachment of Gold Nanoparticles to Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    Xi Cheng MA; Ning LUN; Shu Lin WEN

    2005-01-01

    Carbon nanotubes were initially chemically modified with an H2SO4-HNO3 treatment,and subsequently activated with Pd-Sn catalytic nuclei via a one-step activation approach. These activated nanotubes were used as precursors for obtaining gold nanoparticles-attached nanotubes via simple electroless plating. This approach provides an efficient method for attachment of metal nanostructures to carbon nanotubes. Such novel hybrid nanostructures are attractive for many applications.

  4. Carbon nanotube macroelectronics

    Science.gov (United States)

    Zhang, Jialu

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

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

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-03-01

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

  6. Major role of marine vegetation on the oceanic carbon cycle

    NARCIS (Netherlands)

    Duarte, C.M.; Middelburg, J.J.; Caraco, N.

    2005-01-01

    The carbon burial in vegetated sediments, ignored in past assessments of carbon burial in the ocean, was evaluated using a bottom-up approach derived from upscaling a compilation of published individual estimates of carbon burial in vegetated habitats (seagrass meadows, salt marshes and mangrove for

  7. Performance assessment of carbonation process integrated with coal fired power plant to reduce CO2 (carbon dioxide) emissions

    International Nuclear Information System (INIS)

    This paper presents a novel approach to recover energy from mineral carbonation process, one of the CCS (carbon capture and storage) technologies, to reduce its additional energy demand and reports the feasibility of integrating a carbonation process with an existing power plant for reducing CO2 (carbon dioxide) emission. A thermodynamic mass and energy flow model of the carbonation process is developed using Matlab/Simulink software for a range of carbonation temperatures using two naturally available feedstocks, namely serpentine and olivine. The CO2 emissions are reduced if a carbonation system is implemented in the power plant, though the power generation efficiency and net power output are reduced too due to the large amount of extra energy required for the grinding of feedstock and the compression of CO2. The existing power plant efficiency was found to be 36.1%. If a carbonation system is incorporated, the plant efficiency reduces to 22% and 24% using serpentine and olivine feedstocks respectively. However, a significant amount of heat energy can be recovered from exothermic reaction of carbonation and carbonated products. The power plant efficiency can be increased to 35% and 34% again, respectively, when energy from carbonation reaction and carbonated products can be recovered appropriately. - Highlights: • Mineral carbonation technology is one of the carbon capture and storage technologies. • Exothermic heat energy can be recovered from mineral carbonation process. • Mineral carbonation process is energy self-sufficient. • Thermodynamic mass and energy balance model is developed for mineral carbonation

  8. Different Types of Community Residents Low Carbon Consciousness Compared and Environmental Education Approach Select%不同类型社区居民低碳意识对比与环境教育途径选择

    Institute of Scientific and Technical Information of China (English)

    邹君; 刘倩

    2015-01-01

    According to the different regional characteristics,geographic location,population characteristics,living environ-ment,the types of community in Hengyang city is divided into five types of high-grade community,the general community, placement of the housing low rent housing community,community and shanty towns,three aspects of cognition,from low car-bon low carbon,low carbon behavior attitude of residents in low carbon consciousness,establish reasonable evaluation index system,the low carbon consciousness of residents of different types of communities were compared,the study found,different types of communities with different problems,high-grade community,ordinary residents of low carbon consciousness is strong but low carbon behavior needs improve the resettlement community residents,low carbon consciousness medium but low carbon attitude errors,residents of the community,the shantytown housing low-cost low carbon consciousness is weak,the lack of knowledge of low carbon.Aiming at the existing problems of different types of community,selection of media publicity,gov-ernment guidance,carry out activities and pasted posters,reasonable and efficient way to improve environmental education, residents of low carbon environmental protection consciousness,improve the deteriorating environment.%依据不同地域特色、地理位置、居民特征、居住环境等,将衡阳市社区分为高档社区、普通社区、安置房社区、廉租房社区和棚户区五种类型。从低碳认知、低碳态度、低碳行为三个角度评价居民的低碳意识强弱,建立合理评价指标体系,将不同类型社区居民的低碳意识进行对比。研究发现,不同类型社区存在不同的问题,高档社区、普通社区居民低碳意识较强但低碳行为有待改善,安置社区居民低碳意识中等但低碳态度存在偏差,廉租房社区、棚户区居民低碳意识较弱,低碳知识缺乏。针对不同类型社区存在的问题

  9. Carbon classified?

    DEFF Research Database (Denmark)

    Lippert, Ingmar

    2012-01-01

    . Using an actor- network theory (ANT) framework, the aim is to investigate the actors who bring together the elements needed to classify their carbon emission sources and unpack the heterogeneous relations drawn on. Based on an ethnographic study of corporate agents of ecological modernisation over...... a period of 13 months, this paper provides an exploration of three cases of enacting classification. Drawing on ANT, we problematise the silencing of a range of possible modalities of consumption facts and point to the ontological ethics involved in such performances. In a context of global warming...

  10. All-Carbon Electrode Consisting of Carbon Nanotubes on Graphite Foil for Flexible Electrochemical Applications

    Directory of Open Access Journals (Sweden)

    Je-Hwang Ryu

    2014-03-01

    Full Text Available We demonstrate the fabrication of an all-carbon electrode by plasma-enhanced chemical vapor deposition for use in flexible electrochemical applications. The electrode is composed of vertically aligned carbon nanotubes that are grown directly on a flexible graphite foil. Being all-carbon, the simple fabrication process and the excellent electrochemical characteristics present an approach through which high-performance, highly-stable and cost-effective electrochemical applications can be achieved.

  11. Soil carbon sequestration in mixed farming landscapes: Insights from the Lachlan soil carbon project

    OpenAIRE

    Pearson, Leonie J.; Crean, Jason; Badgery, Warwick; Murphy, Brian; Rawson, Andrew; Capon, Timothy; Reeson, Andrew

    2012-01-01

    The potential for soil carbon sequestration to play a significant role in meeting Australia’s greenhouse reduction targets has attracted widespread interest. Despite this interest, the economic scope for soil carbon sequestration remains poorly understood and the practical approaches that could be used to capture any opportunities have not been explored. In this paper we present preliminary results on a pilot soil carbon sequestration variable price, reverse tender auction in the mixed (wheat...

  12. Production of templated carbon nano materials, carbon nanofibers and super capasitors

    OpenAIRE

    Sakintuna, Billur; Dumanlı, Ahu Gümrah; Dumanli, Ahu Gumrah; Nalbant, Aslı; Nalbant, Asli; Erden, Ayça; Erden, Ayca; Yürüm, Yuda; Yurum, Yuda

    2008-01-01

    i. Porous carbons are usually obtained via carbonization of precursors of natural or synthetic origin, followed by activation. To meet the requirements, a novel approach, the template carbonization method, has been proposed. Replication, the process of filling the external and / or internal pores of a solid with a different material, physically or chemically separating the resulting material from the template, is a technique that is widely used in microporosity and printing. Th...

  13. Developing a Carbon Observing System

    Science.gov (United States)

    Moore, B., III

    2015-12-01

    There is a clear need to better understand and predict future climate change, so that science can more confidently inform climate policy, including adaptation planning and future mitigation strategies. Understanding carbon cycle feedbacks, and the relationship between emissions (fossil and land use) and the resulting atmospheric carbon dioxide (CO2) and methane (CH4) concentrations in a changing climate has been recognized as an important goal by the IPCC. The existing surface greenhouse gas observing networks provide accurate and precise measurements of background values, but they are not configured to target the extended, complex and dynamic regions of the carbon budget. Space Agencies around the globe are committed to CO2 and CH4 observations: GOSAT-1/2, OCO-2/3, MERLin, TanSat, and CarbonSat. In addition to these Low Earth Orbit (LEO) missions, a new mission in Geostationary Orbit (GEO), geoCARB, which would provide mapping-like measurements of carbon dioxide, methane, and carbon monoxide concentrations over major land areas, has been recently proposed to the NASA Venture Program. These pioneering missions do not provide the spatial/temporal coverage to answer the key carbon-climate questions at process relevant scales nor do they address the distribution and quantification of anthropogenic sources at urban scales. They do demonstrate, however, that a well-planned future system of system integrating space-based LEO and GEO missions with extensive in situ observations could provide the accuracy, spatial resolution, and coverage needed to address critical open issues in the carbon-climate system. Dr. Diana Wickland devoted enormous energy in developing a comprehensive apprioach to understand the global carbon cycle; she understood well that an integrated, coordinated, international approach is needed. This shines through in her recent contribution in co-chairing the team that produced the "CEOS Strategy for Carbon Observations from Space." A NASA-funded community

  14. Binding of calcium and carbonate to polyacrylates.

    Science.gov (United States)

    Tribello, Gareth A; Liew, CheeChin; Parrinello, Michele

    2009-05-21

    Polyacrylate molecules can be used to slow the growth of calcium carbonate. However, little is known about the mechanism by which the molecules impede the growth rate. A recent computational study (Bulo et al. Macromolecules 2007, 40, 3437) used metadynamics to investigate the binding of calcium to polyacrylate chains and has thrown some light on the coiling and precipitation of these polymers. We extend these simulations to examine the binding of calcium and carbonate to polyacrylate chains. We show that calcium complexed with both carbonate and polyacrylate is a very stable species. The free energies of calcium-carbonate-polyacrylate complexes, with different polymer configurations, are calculated, and differences in the free energy of the binding of carbonate are shown to be due to differences in the amount of steric hindrance about the calcium, which prevents the approach of the carbonate ion. PMID:19400592

  15. Carbon Nanomembranes.

    Science.gov (United States)

    Turchanin, Andrey; Gölzhäuser, Armin

    2016-08-01

    Carbon nanomembranes (CNMs) are synthetic 2D carbon sheets with tailored physical or chemical properties. These depend on the structure, molecular composition, and surroundings on either side. Due to their molecular thickness, they can be regarded as "interfaces without bulk" separating regions of different gaseous, liquid, or solid components and controlling the materials exchange between them. Here, a universal scheme for the fabrication of 1 nm-thick, mechanically stable, functional CNMs is presented. CNMs can be further modified, for example perforated by ion bombardment or chemically functionalized by the binding of other molecules onto the surfaces. The underlying physical and chemical mechanisms are described, and examples are presented for the engineering of complex surface architectures, e.g., nanopatterns of proteins, fluorescent dyes, or polymer brushes. A simple transfer procedure allows CNMs to be placed on various support structures, which makes them available for diverse applications: supports for electron and X-ray microscopy, nanolithography, nanosieves, Janus nanomembranes, polymer carpets, complex layered structures, functionalization of graphene, novel nanoelectronic and nanomechanical devices. To close, the potential of CNMs in filtration and sensorics is discussed. Based on tests for the separation of gas molecules, it is argued that ballistic membranes may play a prominent role in future efforts of materials separation. PMID:27281234

  16. Carbon nanowalls grown by microwave plasma enhanced chemical vapor deposition during the carbonization of polyacrylonitrile fibers

    Energy Technology Data Exchange (ETDEWEB)

    Li Jiangling; Su Shi; Kundrat, Vojtech; Abbot, Andrew M.; Ye, Haitao [School of Engineering and Applied Science, Aston University, Birmingham B4 7ET (United Kingdom); Zhou Lei [Department of Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT (United Kingdom); Mushtaq, Fajer [Department of Mechanical Engineering, ETH Zurich, Zurich 8092 (Switzerland); Ouyang Defang [School of Life and Health Science, Aston University, Birmingham B4 7ET (United Kingdom); James, David; Roberts, Darren [Thermo Fisher Scientific, Stafford House, Hemel Hempstead HP2 7GE (United Kingdom)

    2013-01-14

    We used microwave plasma enhanced chemical vapor deposition (MPECVD) to carbonize an electrospun polyacrylonitrile (PAN) precursor to form carbon fibers. Scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the fibers at different evolution stages. It was found that MPECVD-carbonized PAN fibers do not exhibit any significant change in the fiber diameter, whilst conventionally carbonized PAN fibers show a 33% reduction in the fiber diameter. An additional coating of carbon nanowalls (CNWs) was formed on the surface of the carbonized PAN fibers during the MPECVD process without the assistance of any metallic catalysts. The result presented here may have a potential to develop a novel, economical, and straightforward approach towards the mass production of carbon fibrous materials containing CNWs.

  17. Carbon nanowalls grown by microwave plasma enhanced chemical vapor deposition during the carbonization of polyacrylonitrile fibers

    Science.gov (United States)

    Li, Jiangling; Su, Shi; Zhou, Lei; Kundrát, Vojtěch; Abbot, Andrew M.; Mushtaq, Fajer; Ouyang, Defang; James, David; Roberts, Darren; Ye, Haitao

    2013-01-01

    We used microwave plasma enhanced chemical vapor deposition (MPECVD) to carbonize an electrospun polyacrylonitrile (PAN) precursor to form carbon fibers. Scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the fibers at different evolution stages. It was found that MPECVD-carbonized PAN fibers do not exhibit any significant change in the fiber diameter, whilst conventionally carbonized PAN fibers show a 33% reduction in the fiber diameter. An additional coating of carbon nanowalls (CNWs) was formed on the surface of the carbonized PAN fibers during the MPECVD process without the assistance of any metallic catalysts. The result presented here may have a potential to develop a novel, economical, and straightforward approach towards the mass production of carbon fibrous materials containing CNWs.

  18. Forest soil carbon is threatened by intensive biomass harvesting

    OpenAIRE

    Achat, David L.; Mathieu Fortin; Guy Landmann; Bruno Ringeval; Laurent Augusto

    2015-01-01

    Forests play a key role in the carbon cycle as they store huge quantities of organic carbon, most of which is stored in soils, with a smaller part being held in vegetation. While the carbon storage capacity of forests is influenced by forestry, the long-term impacts of forest managers’ decisions on soil organic carbon (SOC) remain unclear. Using a meta-analysis approach, we showed that conventional biomass harvests preserved the SOC of forests, unlike intensive harvests where logging residues...

  19. The Carbon Budget of California

    Science.gov (United States)

    Potter, C. S.

    2009-12-01

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

  20. Trading forest carbon

    Science.gov (United States)

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

  1. Switching the Cleavage Sites in Palladium on Carbon-Catalyzed Carbon-Carbon Bond Disconnection.

    Science.gov (United States)

    Hattori, Tomohiro; Takakura, Ryoya; Ichikawa, Tomohiro; Sawama, Yoshinari; Monguchi, Yasunari; Sajiki, Hironao

    2016-04-01

    We have demonstrated a palladium on carbon-catalyzed approach to regioselectively alter the cleavage sites of the C-C bonds of cinnamaldehyde derivatives by a slight change in the reaction conditions in isopropanol under an O2 atmosphere. Styrene derivatives could be selectively formed by the addition of Na2CO3 in association with the dissociation of carbon monoxide, while benzaldehyde derivatives were generated by the addition of CuCl and morpholine instead of Na2CO3. PMID:26944077

  2. Quantifying global terrestrial carbon influx and storage as stimulated by an increase in atmospheric carbon dioxide concentration

    OpenAIRE

    Luo, Yiqi

    1997-01-01

    EXTRACT (SEE PDF FOR FULL ABSTRACT): Measurements of spatial and temporal distributions of carbon dioxide concentration and carbon-13/carbon-12 ratio in the atmosphere suggest a strong biospheric carbon sink in terrestrial ecosystems. Quantifying the sink, however, has become an enormous challenge for Earth system scientists because of great uncertainties associated with biological variation and environmental heterogeneity in the ecosystems. This paper presents an approach that uses two d...

  3. An Approach to Carbon Dioxide Density in Soil of Southern Suburb Grassland in Xi'an%西安市南郊草地土壤CO2释放规律探讨

    Institute of Scientific and Technical Information of China (English)

    张冲; 赵景波; 谷岳; 马小军; 张杰; 刘娇

    2011-01-01

    To understand carbon dioxide density in soil at different depths and their impact on atmospheric carbon dioxide as well as the role in global carbon cycle,carbon dioxide concentration in soil in the range of 1 to 10 metre depths was measured by using infrared CO2 monitor at the grassland of Weiqu Town in southern Xi'an city in June 2010.Two groups of six boreholes each 1,2,4,6,8 and 10 metres deep respectively were ready for the observation day and night.The results have shown that carbon dioxide density in soil of this area was generally higher than that in the air at ground level whilst varying among different depths.There has been a profile of apparently increasing release of carbon dioxide in soil as goes deepening.As carbon dioxide concentration in soil was found lower at night and higher in the daytime,its diurnal variation at certain depths was evidently presenting a pattern of rise first and then decline round-the-clock from 7:15 am one morning till the next.At the same depth,in soil with more moisture,carbon dioxide density was significantly higher than that in soil with less humidity.Diurnal temperature variation was the key factor that led to the changes in carbon dioxide concentration in soil,and their correlation was relatively high showing positive but somewhat lagging.%为探讨土壤不同深度CO2浓度和对大气CO2的影响以及在全球碳循环中的作用,利用红外CO2监测仪,在2010年6月对西安市南部韦曲镇草地1~10 m深度的土壤进行了1、2、4、6、8、10 m各2组共12个钻孔的CO2浓度昼夜观测。结果显示,该区所有土壤CO2浓度均高于地表上空大气中CO2浓度,不同深度释放的CO2浓度差异较大,CO2释放量随深度增加呈现明显增大的趋势;土壤CO2浓度夜间低,白天高,昼夜变化明显,从早7:15到次日早7:15各深度均呈现由低到高再到低的变化规律;含水量较高的同一深度土层CO2浓度明显高于含水量较低的土层。土壤CO2浓度

  4. Application of Alkaline Waterflooding to a High Acidity Crude Oil Application de l'injection d'eau alcaline au cas d'un pétrole brut à forte acidité

    Directory of Open Access Journals (Sweden)

    Abdel-Waly A.

    2006-11-01

    Full Text Available The main objective of this work was to study the enhanced recovery of a high acidity crude oil (South Geisum crude by alkaline solutions. Different properties of South Geisum crude oil, namely acidity, interfacial tension, and contact angle, were investigated. Displacement tests were carried out to study the effect of alkaline slug concentration, slug size, oil alkali type, and temperature viscosity on recovery. South Geisum crude oil is a highly acidic crude (4. 38 mg KOH/g. It was found that the interfacial tension between crude oil and formation water decreases with increasing alkaline concentration until it reaches a minimum, after which it increases again with a further increase in alkaline concentration. Interfacial tension between crude oil and displacement water also decreases with increasing alkaline concentration. Contact angle measurements indicated oil-wetting conditions that increase by the addition of alkaline solutions. Displacement floods showed that, at the early stages of displacement, oil recovery increases with increasing alkaline concentration until it reaches a maximum at 4 % by weight NaOH concentration. Also, at such early stages, an excessive increase in alkaline concentration results in lower oil recovery. On the other hand, after the injection of many pore volumes of water, oil recovery is almost the same regardless of the alkaline concentration. It was found also that oil recovery increases with increasing alkaline slug size until it reaches a maximum at 15 % PV, after which increasing slug size results in decreasing oil recovery (this result has not as yet been reported in the literature. Sodium hydroxide slugs produce more oil recovery than sodium carbonate slugs. Oil recovery increases with increasing temperature (from 25 to 55°C and decreasing oil viscosity. Cet article traite de la récupération, au moyen de solutions alcalines, d'un pétrole brut à forte acidité (brut de Geisum-Sud. Différentes propri

  5. Carbon footprinting of electronic products

    International Nuclear Information System (INIS)

    Highlights: • Challenges in adopting existing CF standards for electronic products are discussed. • Carbon footprint of electronic products is underestimated using existing standards. • Multipronged approach is presented to overcome the identified challenges. • Multipronged approach demonstrated on commercial and military grade DC–DC converter system. - Abstract: In order to mitigate the effects of global warming, companies are being compelled by governments, investors, and customers to control their greenhouse gas (GHG) emissions. Similar to the European Union’s legislation on the airline industry, legislation is expected to require the electronics industry to assess their product’s carbon footprint before sale or use, as the electronics industry’s contribution to global GHG emissions is comparable to the airline industry’s contribution. Thus, it is necessary for members of the electronics industry to assess their current GHG emission rates and identify methods to reduce environmental impacts. Organizations use Carbon Footprint (CF) analysis methods to identify and quantify the GHG emissions associated with the life cycle stages of their product or services. This paper discusses the prevailing methods used by organizations to estimate the CF of their electronics products and identifies the challenges faced by the electronics industry when adopting these methods in an environment of decreasing product development cycles with complex and diffuse supply chains. We find that, as a result of the inconsistencies arising from the system boundary selection methods and databases, the use of outdated LCA approaches, and the lack of supplier’s emissions-related data, the CFs of electronic products are typically underestimated. To address these challenges, we present a comprehensive approach to the carbon footprinting of electronic products that involves the use of product-group-oriented standards, hybrid life cycle assessment techniques, and the

  6. Approach and practice of regional energy planning under low carbon situation%低碳形势下的区域能源规划方法及实践

    Institute of Scientific and Technical Information of China (English)

    徐宝萍; 徐稳龙

    2012-01-01

    Regional energy planning is an important measure for realizing the low carbon target. Through summarizing the low carbon energy planning practice of several new districts, organizes the general thought and framework of regional energy planning and distills six points of concern in the planning process, including low carbon estimation and index control, overall planning of infrastructure, linkage between city planning and other special low carbon eco-planning, investment and financing and operation mode, planning management mechanism, and construction of growing energy system combined with project schedule. Carries out an example analysis of low carbon energy planning for a new district of Beijing. Proposes that energy planning should be standardized as early as possible and planned comprehensively from the aspects of technology, market and management to realize the low carbon target.%区域能源规划是实现低碳目标的重要措施.通过总结多个新区的低碳能源规划实践,梳理了区域能源规划总体思路及工作框架,提炼出在规划过程中需关注的6个要点:低碳评估及指标控制、基础设施综合统筹、与城市规划及其他低碳生态专项规划联动、投融资与运营模式研究、规划落实管理机制、与项目进度结合构建成长型能源系统.结合北京市某新区低碳能源规划,按规划工作流程逐步进行了案例分析.认为能源规划工作应尽早实现标准化,并从技术、市场、管理等多角度出发,全面统筹,使低碳目标得到落实.

  7. Carbon Farming as a Carbon Negative Technology

    Science.gov (United States)

    Anderson, C.; Laird, D.; Hayes, D. J.

    2015-12-01

    Carbon farms have a pivotal role in national and international efforts to mitigate and adapt to climate change. A carbon farm in its broadest sense is one that reduces greenhouse gas (GHG) emissions or captures and holds carbon in vegetation and soils. Their capacity to remove carbon from the air and store it safely and permanently, while providing additional human and ecosystem benefits, means they could contribute significantly to national efforts to stabilize or reduce GHGs. We examine carbon farms in the context of corn and soybean production agriculture. We illustrate, using Iowa data but with relevance across United States corn and soybean production, the potential for carbon farms to reduce human GHG emissions and sequester carbon permanently at a rate that has meaningful impact on global greenhouse gas concentration. Carbon has been viewed as a next generation cash crop in Iowa for over a decade. The carbon farm perspective, however, goes beyond carbon as cash crop to make carbon the center of an entire farm enterprise. The transformation is possible through slight adjustment crop practices mixed with advances in technology to sequester carbon through biochar. We examine carbon balance of Iowa agriculture given only the combination of slight reduction in fertilizer and sequestration by biochar. We find the following. Iowa carbon farms could turn Iowa agriculture into a carbon sink. The estimated range of GHG reduction by statewide implementation of carbon farms is 19.46 to 90.27 MMt CO2-equivalent (CO2-e), while the current agricultural CO2-e emission estimate is 35.38 MMt CO2-e. Iowa carbon farm GHG reduction would exceed Iowa GHG reduction by wind energy (8.7 MMt CO2-e) and could exceed combined reductions from wind energy and corn grain ethanol (10.7 MMt CO2-e; 19.4 MMt CO2-e combined). In fact, Iowa carbon farms alone could exceed GHG reduction from national corn grain ethanol production (39.6 MMt CO2-e). A carbon price accessible to agricultural

  8. Net Ecosystem Carbon Flux

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Net Ecosystem Carbon Flux is defined as the year-over-year change in Total Ecosystem Carbon Stock, or the net rate of carbon exchange between an ecosystem and the...

  9. Carbon Monoxide (CO)

    Science.gov (United States)

    ... IAQ) » Carbon Monoxide's Impact on Indoor Air Quality Carbon Monoxide's Impact on Indoor Air Quality On this ... length of exposure. Top of Page Sources of Carbon Monoxide Sources of CO include: unvented kerosene and ...

  10. Carbon Monoxide Poisoning

    Science.gov (United States)

    ... Recommend on Facebook Tweet Share Compartir What is Carbon Monoxide? Carbon monoxide, or “CO,” is an odorless, colorless gas that can kill you. Carbon monoxide detector Where is CO found? CO is ...

  11. Towards an integrated scientific approach for carbon accounting in forestry. COST E21 Workshop. Contribution of forests and forestry to mitigate greenhouse effects. Joensuu (Finland). 28-30 Sep 2000

    OpenAIRE

    Karjalainen T.; Laitat E.; Loustau D.; Lindner M.

    2000-01-01

    In the COST E21-Action ""Contribution of Forests and Forestry to Mitigate Greenhouse Effects"", emphasis is put on the quantification of carbon storage in the forest ecosystems and on the understanding of linkages between human activities and climate change, particularly the role of forests and forestry. COST E21 integrates natural, socio-economic as well as methodological aspects relevant for reporting under the unitéd Nations Framework Convention on Climate Change and the Kyoto Protocol, as...

  12. Reconstructing Late Ordovician carbon cycle variations

    Science.gov (United States)

    Pancost, Richard D.; Freeman, Katherine H.; Herrmann, Achim D.; Patzkowsky, Mark E.; Ainsaar, Leho; Martma, Tõnu

    2013-03-01

    The role of carbon dioxide in regulating climate during the early Paleozoic, when severe glaciations occurred during a putative greenhouse world, remains unclear. Here, we present the first molecular carbon isotope proxy-based estimates for Late Ordovician (early Katian) pCO2 levels, and explore the limitations of applying this approach to the reconstruction of Paleozoic pCO2. Carbon isotope profiles from three sites in Laurentia (Iowa, Ontario and Pennsylvania) and one site in Baltica (Estonia) exhibit overall low isotope fractionation between organic and inorganic carbon during photosynthesis (ɛp) and these values declined during the early Katian carbonate carbon isotope excursion (or Guttenberg Carbon Isotope Excursion, GICE). Algal ɛp values are sensitive to changes in CO2 concentrations, algae cell morphologies, and cell growth rates. To constrain these factors, we present molecular evidence that a decrease in the relative abundance of cyanobacteria and a change in the eukaryotic algae community co-occurred with the GICE. Regardless of local biotic or oceanographic influences, a decline in ɛp values indicates photosynthesis was sensitive to carbon concentrations, and via analogy with modern taxa, constrains pCO2 to below ˜8× pre-industrial levels (PIL), or about half of previous estimates. In addition, the global, positive carbon isotope excursions expressed in a wide variety of sedimentary materials (carbonate, bulk organic matter, n-alkanes, acyclic and cyclic isoprenoid hydrocarbons), provide compelling evidence for perturbation of the global carbon cycle, and this was likely associated with a decrease in pCO2 approximately 10 million years prior to the Hirnantian glaciations. Isotopic records from deeper water settings suggest a complex interplay of carbon sources and sinks, with pCO2 increasing prior to and during the early stages of the GICE and then decreasing when organic carbon burial outpaced increased volcanic inputs.

  13. Integral Ring Carbon-Carbon Piston

    Science.gov (United States)

    Northam, G. Burton (Inventor)

    1999-01-01

    An improved structure for a reciprocating internal combustion engine or compressor piston fabricate from carbon-carbon composite materials is disclosed. An integral ring carbon-carbon composite piston, disclosed herein, reduces the need for piston rings and for small clearances by providing a small flexible, integral component around the piston that allows for variation in clearance due to manufacturing tolerances, distortion due to pressure and thermal loads, and variations in thermal expansion differences between the piston and cylinder liner.

  14. Carbon dioxide sequestration by mineral carbonation

    OpenAIRE

    Huijgen, W.J.J.

    2007-01-01

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

  15. Soil Carbon Storage in Christmas Tree Farms: Maximizing Ecosystem Management and Sustainability for Carbon Sequestration

    Science.gov (United States)

    Chapman, S. K.; Shaw, R.; Langley, A.

    2008-12-01

    Management of agroecosystems for the purpose of manipulating soil carbon stocks could be a viable approach for countering rising atmospheric carbon dioxide concentrations, while maximizing sustainability of the agroforestry industry. We investigated the carbon storage potential of Christmas tree farms in the southern Appalachian mountains as a potential model for the impacts of land management on soil carbon. We quantified soil carbon stocks across a gradient of cultivation duration and herbicide management. We compared soil carbon in farms to that in adjacent pastures and native forests that represent a control group to account for variability in other soil-forming factors. We partitioned tree farm soil carbon into fractions delineated by stability, an important determinant of long-term sequestration potential. Soil carbon stocks in the intermediate pool are significantly greater in the tree farms under cultivation for longer periods of time than in the younger tree farms. This pool can be quite large, yet has the ability to repond to biological environmental changes on the centennial time scale. Pasture soil carbon was significantly greater than both forest and tree farm soil carbon, which were not different from each other. These data can help inform land management and soil carbon sequestration strategies.

  16. Carbon Residence Times in Pedogenic Carbonate Pools

    Science.gov (United States)

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

    2013-12-01

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

  17. Carbon dioxide sequestration by mineral carbonation

    NARCIS (Netherlands)

    Huijgen, W.J.J.

    2007-01-01

    The increasing atmospheric carbon dioxide (CO2) concentration, mainly caused by fossil fuel combustion, has lead to concerns about global warming. A possible technology that can contribute to the reduction of carbon dioxide emissions is CO2 sequestration by mineral carbonation. The basic concept beh

  18. Optical and Electronic Properties of 2D Graphitic Carbon-Nitride and Carbon Enriched Alloys

    Science.gov (United States)

    Therrien, Joel; Li, Yancen; Schmidt, Daniel; Masaki, Michael; Syed, Abdulmannan

    The two-dimensional form of graphitic carbon-nitride (gCN) has been successfully synthesized using a simple CVD process. In it's pure form, the carbon to nitrogen ratio is 0.75. By adding a carbon bearing gas to the growth environment, the C/N ratio can be increased, ultimately reaching the pure carbon form: graphene. Unlike attempts at making a 2D alloy system out of BCN, the CN system does not suffer from phase segregation and thus forms a homogeneous alloy. The synthesis approach and electronic and optical properties will be presented for the pure gCN and a selection of alloy compositions.

  19. The carbon budget of California

    International Nuclear Information System (INIS)

    The carbon budget of a region can be defined as the sum of annual fluxes of carbon dioxide (CO2) and methane (CH4) greenhouse gases (GHGs) into and out of the regional surface coverage area. According to the state government's recent inventory, California's carbon budget is presently dominated by 115 MMTCE per year in fossil fuel emissions of CO2 (>85% of total annual GHG emissions) to meet energy and transportation requirements. Other notable (non-ecosystem) sources of carbon GHG emissions in 2004 were from cement- and lime-making industries (7%), livestock-based agriculture (5%), and waste treatment activities (2%). The NASA-CASA (Carnegie Ames Stanford Approach) simulation model based on satellite observations of monthly vegetation cover (including those from the Moderate Resolution Imaging Spectroradiometer, MODIS) was used to estimate net ecosystem fluxes and vegetation biomass production over the period 1990-2004. California's annual NPP for all ecosystems in the early 2000s (estimated by CASA at 120 MMTCE per year) was roughly equivalent to its annual fossil fuel emission rates for carbon. However, since natural ecosystems can accumulate only a small fraction of this annual NPP total in long-term storage pools, the net ecosystem sink flux for atmospheric carbon across the state was estimated at a maximum rate of about 24 MMTCE per year under favorable precipitation conditions. Under less favorable precipitation conditions, such as those experienced during the early 1990s, ecosystems statewide were estimated to have lost nearly 15 MMTCE per year to the atmosphere. Considering the large amounts of carbon estimated by CASA to be stored in forests, shrublands, and rangelands across the state, the importance of protection of the natural NPP capacity of California ecosystems cannot be overemphasized.

  20. Carbon coatings for medical implants

    OpenAIRE

    K. Bakowicz-Mitura; P. Couvrat; I. Kotela; P. Louda; D. Batory; J. Grabarczyk

    2007-01-01

    Purpose: In this paper we report in vitro and in vivo results of Nanocrystalline Diamond Coatings whichare used in medicine onto medical implants The very important property of carbon coatings is the protectionliving organism against the metalosis. Different medical implants with complicated shapes are covering byNanocrystalline Diamond Coatings by RF dense plasma CVD.Design/methodology/approach: 1) Material characterizations of deposited coatings have been evaluated by using:Transmission Ele...

  1. Geomorphic control of landscape carbon accumulation

    Science.gov (United States)

    Rosenbloom, N.A.; Harden, J.W.; Neff, J.C.; Schimel, D.S.

    2006-01-01

    We use the CREEP process-response model to simulate soil organic carbon accumulation in an undisturbed prairie site in Iowa. Our primary objectives are to identify spatial patterns of carbon accumulation, and explore the effect of erosion on basin-scale C accumulation. Our results point to two general findings. First, redistribution of soil carbon by erosion results in a net increase in basin-wide carbon storage relative to a noneroding environment. Landscape-average mean residence times are increased in an eroding landscape owing to the burial/preservation of otherwise labile C. Second, field observations taken along a slope transect may overlook significant intraslope variations in carbon accumulation. Spatial patterns of modeled deep C accumulation are complex. While surface carbon with its relatively short equilibration time is predictable from surface properties, deep carbon is strongly influenced by the landscape's geomorphic and climatic history, resulting in wide spatial variability. Convergence and divergence associated with upland swales and interfluves result in bimodal carbon distributions in upper and mid slopes; variability in carbon storage within modeled mid slopes was as high as simulated differences between erosional shoulders and depositional valley bottoms. The bimodality of mid-slope C variability in the model suggests that a three-dimensional sampling strategy is preferable over the traditional two-dimensional analog or "catena" approach. Copyright 2006 by the American Geophysical Union.

  2. From carbon nanotubes to carbon atomic chains

    Science.gov (United States)

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

    2010-10-01

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

  3. Forecasting carbon dioxide emissions.

    Science.gov (United States)

    Zhao, Xiaobing; Du, Ding

    2015-09-01

    This study extends the literature on forecasting carbon dioxide (CO2) emissions by applying the reduced-form econometrics approach of Schmalensee et al. (1998) to a more recent sample period, the post-1997 period. Using the post-1997 period is motivated by the observation that the strengthening pace of global climate policy may have been accelerated since 1997. Based on our parameter estimates, we project 25% reduc