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Sample records for carbonate approaching waterflood

  1. Smart Waterflooding in Carbonate Reservoirs

    DEFF Research Database (Denmark)

    Zahid, Adeel

    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...... imbibition rather than forced flooding. The objective of the third step of this project was to investigate the potential of high salinity waterflooding process by carrying out experiments with reservoir chalk samples. We carried out waterflooding instead of spontaneous imbibition using core plugs with and...... without aging. The total oil recovery, recovery rate and interaction mechanisms of ions with rock were studied for different injected fluids under different temperatures and wettability conditions. Experimental results demonstrate that the oil recovery mechanism under high salinity seawater flooding at...

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

    International Nuclear Information System (INIS)

    The first project objective is to utilize reservoir characterization and advanced technologies to optimize the design of a carbon dioxide (CO2) 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 project objective is to demonstrate the performance and economic viability of the project in the field. All work during the second quarter falls within the demonstration project

  3. 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.

  4. DESIGN AND IMPLEMENTATION OF A CO2 FLOOD UTILIZING ADVANCED RESERVOIR CHARACTERIZATION AND HORIZONTAL INJECTION WELLS IN A SHALLOW SHELF CARBONATE APPROACHING WATERFLOOD DEPLETION

    Energy Technology Data Exchange (ETDEWEB)

    K.J. Harpole; Ed G. Durrett; Susan Snow; J.S. Bles; Carlon Robertson; C.D. Caldwell; D.J. Harms; R.L. King; B.A. Baldwin; D. Wegener; M. Navarrette

    2002-09-01

    The purpose of this project was to economically design an optimum carbon dioxide (CO{sub 2}) flood for a mature waterflood nearing its economic abandonment. The original project utilized advanced reservoir characterization and CO{sub 2} 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. The Unit was a mature waterflood with water cut exceeding 95%. Oil must be mobilized through the use of a miscible or near-miscible fluid to recover significant additional reserves. Also, because the unit was relatively small, it did not have the benefit of economies of scale inherent in normal larger scale projects. Thus, new and innovative methods were required to reduce investment and operating costs. Two primary methods used to accomplish improved economics were use of reservoir characterization to restrict the flood to the higher quality rock in the unit and use of horizontal injection wells to cut investment and operating costs. The project consisted of two budget phases. Budget Phase I started in June 1994 and ended late June 1996. In this phase Reservoir Analysis, Characterization Tasks and Advanced Technology Definition Tasks were completed. Completion enabled the project to be designed, evaluated, and an Authority for Expenditure (AFE) for project implementation submitted to working interest owners for approval. Budget Phase II consisted of the implementation and execution of the project in the field. Phase II was completed in July 2001. Performance monitoring, during Phase II, by mid 1998 identified the majority of producing wells which under performed their anticipated withdrawal rates. Newly drilled and re-activated wells had lower offtake rates than originally forecasted. As a result of poor offtake, higher reservoir pressure was a concern

  5. 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; ANNUAL

    International Nuclear Information System (INIS)

    The principle objective of this project is to demonstrate the economic viability and widespread applicability of an innovative reservoir management and carbon dioxide (CO2) flood project development approach for improving CO2 flood project economics in shallow shelf carbonate (SSC) reservoirs

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

    DEFF Research Database (Denmark)

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

    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...

  7. 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.

  8. Integrated Approach Towards the Application of Horizontal Wells to Improve Waterflooding Performance; FINAL

    International Nuclear Information System (INIS)

    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

  9. 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.

  10. 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)

  11. 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.

  12. 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.

  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. 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 and...... equation of state is used to account for brine density variation with regard to pressure and composition. We present a numerical study of the evolution of the reservoir parameters in the framework of the developed model. It is demonstrated that the systems characterized by large Damkohler numbers (fast...

  15. 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.

  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. Waterflooding optimization in uncertain geological scenarios

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...... realizations is maximized. In this paper, we both consider an open-loop optimization scenario, with no feedback, and a closed-loop optimization scenario. The closed-loop scenario is implemented in a moving horizon manner and feedback is obtained using an ensemble Kalman filter for estimation of the....... It uses the mean of the ensemble as its permeability field. Simulations reveal that the RO strategy and the certainty equivalent strategy give a higher NPV compared to the reactive strategy. Surprisingly, the RO strategy and the certainty equivalent strategy give similar NPVs. Consequently, the...

  18. Electrochemical Approach to Carbon Nanostructures

    Czech Academy of Sciences Publication Activity Database

    Kavan, Ladislav; Hlavatý, Jaromír; Janda, Pavel

    Barcelona : Universitat de Barcelona, 2004 - (Brillas, E.; Cabot, P.), s. 77-101 ISBN 84-475-2639-9 R&D Projects: GA AV ČR IAA4040306; GA AV ČR KSK4040110 Keywords : carbon nanotubes * fullerenes * spectroelectrochemistry Subject RIV: CG - Electrochemistry

  19. Analyzing waterflood responses for Pekisko B

    Energy Technology Data Exchange (ETDEWEB)

    Fedenczuk, L. [Gambit Consulting Ltd., (Canada); Pedersen, P.; Marshall, M. [Ocelot Energy Inc., Calgary, AB (Canada)

    1999-11-01

    A study was conducted between January 1990 and September 1997 to find fluid communication between injectors and producers in the Pekisko B pool, the largest oil pool in the Sylvan Lake Field, and the third largest oil pool in the Gilby, Medicine River and Sylvan Lake Field areas in Alberta. A total of eight injectors (patterns) and all wells within a radius of 1700 m from any specific injector were analyzed. The analysis was based on responses of producers to change in the injection rates. The strength of the oil response was measured as the correlation between the oil rate and the injection rate. Three sets of primary parameters characterized the oil, gas and water response. The waterflood responses were presented in the form of special XY diagrams. All injectors showed medium or strong communication with producers as defined by the oil responses. This method of finding fluid responses proved to be more cost and time effective than conventional engineering methods. 4 refs., 8 figs.

  20. 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.

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

    International Nuclear Information System (INIS)

    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

  2. Understanding the Carbon Cycle : A Jigsaw Approach

    Science.gov (United States)

    Hastings, D. W.

    2006-12-01

    A thorough understanding of the carbon cycle is fundamental to understanding the eventual fate of CO2. To achieve this, students must understand individual processes, such as photosynthesis and respiration, as well as an integrated knowledge of how these processes relate to each other. In this "jigsaw" exercise, each student is assigned one five fundamental geochemical processes in the short- term carbon cycle to research and fully understand. In class, students first meet with others who have studied the same process to strengthen and deepen their understanding of this process. They then form teams of five students and explain to other students their particular process. In exchange, other students explain the other aspects of the carbon cycle. At the end of class all students will know about each of the five processes, and thus develop an integrated understanding of the entire carbon cycle. This approach is an efficient method for students to learn the material. As in a jigsaw puzzle, each student's part is essential for the full understanding of the carbon cycle. Since each student's part is essential, then each student is essential, which is what makes this strategy effective The jigsaw approach encourages listening, engagement, and collaboration by giving each member of the group an essential part to play in the academic activity.

  3. Increasing Waterflood Reserves in the Wilmington Oil Field Through Reservoir Characterization and Reservoir Management

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-10

    This project is 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.

  4. Design and Implementation of a CO2 Flood Utilizing Advanced Reservoir Characterization and Horizontal Injection Wells In a Shallow Shelf Carbonate Approaching Waterflood Depletion; ANNUAL

    International Nuclear Information System (INIS)

    This project consist of two budget phases. Budget Phase I started in June 1994 and ended late June 1996. During this phase the Reservoir Analysis and Characterization Task and the Advanced Technology Definition Task were completed. Completion of these tasks enabled the project to be designed, and an Authority for Expenditure (AFE) for project implementation to be generated and submitted to the working interest owners for approval. Budget Phase II consists of the implementation and execution of the project in the field

  5. Novel biological approaches to carbon mineralization

    Science.gov (United States)

    Power, Ian; Kenward, Paul; Harrison, Anna; Dipple, Gregory; Raudsepp, Mati; Wilson, Siobhan; Southam, Gordon

    2015-04-01

    Innovative approaches for accelerating and manipulating fundamental geochemical processes are necessary to develop carbon mineralization as a viable strategy for the mitigation of greenhouse gas emissions. Mg-carbonate formation is of interest for both ex situ and in situ CO2 sequestration strategies1. Accordingly, we have investigated approaches to accelerate these water-rock reactions that produce Mg-carbonate minerals using biological approaches. For instance, CO2-limited conditions are encountered in many systems relevant to CO2 sequestration and represent a severe limitation on carbon mineralization. In carbonation experiments, the supply of CO2 was increased with the use of carbonic anhydrase, an enzyme that catalyzes the hydration of aqueous CO2. The presence of carbonic anhydrase had a dramatic impact on carbonation rates of brucite [Mg(OH)2]2, a mineral of interest for carbon sequestration3. In a CO2-rich aqueous environment, cyanobacteria were able to induce hydrated Mg-carbonate precipitation in microcosm experiments through the alkalinization of their microenvironment and concentration of cations on their cell membranes, which also provide regularly spaced, chemically identical sites for mineral nucleation4. In both lines of investigation, the resulting precipitates were metastable hydrated Mg-carbonate minerals rather then magnesite [MgCO3], the most stable Mg-carbonate and therefore the preferred product forsequestering CO2. Consequently, we have investigated approaches to improve magnesite precipitation rate in these low temperature environments. Inopportunely, rates of magnesite precipitation are severely limited at temperatures below 60 ° C due to the strong hydration of Mg2+ ions in solution5. Yet, carboxyl functional groups (R-COOH) are able to cause desolvation of Mg2+ ions6,7. In microcosm experiments using polystyrene microspheres with a high density of carboxyl groups, we were able to precipitate magnesite at room temperature from slightly

  6. 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.

  7. Experimental waterflooding using polyacrylamide solution in the Romashkinskoe field. [USSR

    Energy Technology Data Exchange (ETDEWEB)

    Zaidullin, G.N.; Lezhenin, V.G.; Lerman, B.A.; Riyanov, A.M.

    1975-01-01

    After the start of waterflooding, productivity of the wells was significantly improved; however, an early breakthrough of water was observed in wells located near the injection contour. This could be attributed to heterogeneity of the formation and high viscosity of oil. This would result in low recovery factors. To improve oil recovery, polymer flooding was started in the fifth horizon of the Romashkinskoe field on a pilot scale. An increase of 8% in the recovery factor is expected over the recovery factor which would be obtained by regular waterflooding. Recovery factors for polymer flooding were calculated by the Buckley-Leverett method with the assumption that water-injection after the polymer slug injection could not change significantly the conductivity of the formation. Field-wise and well-wise data of this pilot test are presented.

  8. 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.

  9. Benefits of a horizontal well in sandstone waterflood

    International Nuclear Information System (INIS)

    This is a case study which describes the planning and results of a horizontal well in a shallow Wilcox sandstone waterflood unit in central Louisiana. The Tremont H-13-1 was OXY USA Inc.'s first horizontal well. Analysis will include examination of the selection criteria, planning, execution, completion, and production. A variety of well and field data is presented and reviewed to access the value of this information as it applies towards other applications. The Cruse Waterflood Unit is a 2100 ft. Wilcox formation in central Louisiana. Production improvements have been 500% or greater for the horizontal well versus adjacent vertical wells. The horizontal well paid out in less than 4 months Results from this well indicate that not only was this project an economic success, but that other fields will similar conditions can be produced in a more profitable manner with horizontal wells

  10. Low Salinity Waterflood in Combination with Surfactant/Polymer; Effect of Surfactant Slug Size

    OpenAIRE

    Al-Ajmi, Adnan Ibrahim Ahmed

    2014-01-01

    In last years, there has been a growing interest in the effect of reducing salinity of injected water in oil recovery. Many studies have showed that low salinity waterflooding is a promising method that can lead to a significant reduction in residual oil saturation compared to traditional waterflooding. The mechanisms behind improved oil recovery by low salinity waterflooding are not fully understood, but many researchers have claimed wettability alteration. In t...

  11. 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...

  12. 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.

  13. 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

  14. 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.

  15. Waterflood improvement in the Permian Basin: Impact of in-situ-stress evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Nolen-Hoeksema, R.C.; Avasthi, J.M. (Chevron Petroleum Technology Co., Houston, TX (United States)); Pape, W.C. (West Australian Petroleum Pty. Ltd., Perth (Australia)); El Rabaa, A.W. (Mobil E and P Technical Center, Dallas, TX (United States))

    1994-11-01

    The authors evaluated in-situ-stress magnitudes and directions to support waterflood improvement programs in McElroy field and North Westbrook Unit. In-situ-stress and hydraulic-fracture directions coincided with directional floodwater effects. This information contributed to successful waterflood realignment programs.

  16. Low-Salinity Waterflooding to Improve Oil Recovery - Historical Field Evidence

    Energy Technology Data Exchange (ETDEWEB)

    Eric P. Robertson

    2007-11-01

    Waterflooding is by far the most widely applied method of improved oil recovery. Crude oil/brine/rock interactions can lead to large variations in the displacement efficiency of wa-terfloods. Laboratory water-flood tests and single-well tracer tests have shown that injection of dilute brine can increase oil recovery, but work designed to test the method on a field scale has not yet been undertaken. Historical waterflood records could unintentionally provide some evidence of improved recovery from waterflooding with lower salinity brine. Nu-merous fields in the Powder River basin of Wyoming have been waterflooded using low salinity brine (about 500 ppm) obtained from the Madison limestone or Fox Hills sandstone. Three Minnelusa formation fields in the basin were identified as potential candidates for waterflood comparisons based on the salinity of the connate and injection water. Historical pro-duction and injection data for these fields were obtained from the public record. Field waterflood data were manipulated to be displayed in the same format as laboratory coreflood re-sults. Recovery from fields using lower salinity injection wa-ter was greater than that using higher salinity injection wa-ter—matching recovery trends for laboratory and single-well tests.

  17. Inhibitor prevents corrosion, scale in Chinese waterflood

    Energy Technology Data Exchange (ETDEWEB)

    Yong, W.; Jianhua, W. (Shengli Design Inst., Dongying (China))

    1994-03-14

    An imidazoline derivative-based series inhibitor has prevented both corrosion and scale formation in produced-water treatment and water-injection equipment in China National Petroleum Co.'s (CNPC) Shengli oil field. Development of the inhibitor started in 1986, and after successful field trials the chemical is now being extensively applied. To increase oil recovery, water injection is widely used in China's onshore oil fields. Oil production in the Shengli oil field, for example, requires injection of about 4 bbl of water/1 bbl of oil produced. The large volumes of produced formation water contain many substances that can cause serious corrosion and scale. Also, the makeup water from other sources, subsurface or surface, complicates water handling. The paper discusses the following: corrosion and scale, oxygen, carbon dioxide, H[sub 2]S and sulfur reducing bacteria, temperature, inhibition, field tests, applications, and economics.

  18. 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.

  19. 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.

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

    International Nuclear Information System (INIS)

    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-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.

  1. 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.

  2. Enhanced Oil Recovery by Horizontal Waterflooding

    Energy Technology Data Exchange (ETDEWEB)

    Scott Robinowitz; Dwight Dauben; June Schmeling

    2005-09-05

    Solar energy has become a major alternative for supplying a substantial fraction of the nation's future energy needs. The U.S. Department of Energy (DOE) supports activities ranging from the demonstration of existing technology to research on future possibilities. At Lawrence Berkeley Laboratory (LBL), projects are in progress that span a wide range of activities, with the emphasis on research to extend the scientific basis for solar energy applications, and on preliminary development of new approaches to solar energy conversion. To assess various solar applications, it is important to quantify the solar resource. Special instruments have been developed and are now in use to measure both direct solar radiation and circum-solar radiation, i.e., the radiation from near the sun resulting from the scattering of sunlight by small particles in the atmosphere. These measurements serve to predict the performance of solar designs that use focusing collectors employing mirrors or lenses to concentrate the sunlight. Efforts have continued at a low level to assist DOE in demonstrating existing solar technology by providing the San Francisco Operations Office (SAN) with technical support for its management of commercial-building solar demonstration projects. Also, a hot water and space-heating system has been installed on an LBL building as part of the DOE facilities Solar Demonstration Program. LBL continues to provide support for the DOE Appropriate Energy Technology grants program. Evaluations are made of the program's effectiveness by, for example, estimating the resulting potential energy savings. LBL also documents innovative features and improvements in economic feasibility as compared to existing conventional systems or applications. In the near future, we expect that LBL research will have a substantial impact in the areas of solar heating and cooling. Conventional and new types of high-performance absorption air conditioners are being developed that are air

  3. 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.)

  4. 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

  5. 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

  6. The use of interruptible power in west Texas waterflood operations

    International Nuclear Information System (INIS)

    Interruptible power purchased from electric utilities has been used by chemical and process industries for many years, but is not generally used in oil producing operations. Interruptible power represents an established option to reduce electric power costs, which are often the oil producer's single largest operating expense. The recent use of interruptible power in Amoco Production Company's West Texas waterflood operations has significantly reduced operating expenses. Interruptible power rates are offered by many electric utility companies; however, the impact on producing operations is generally not known. This paper addresses the initial areas of concern and offers over two years of case history data showing how interruptible power affects operating costs. production equipment, producing rates and safety/environmental operations

  7. 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.

  8. 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.)

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Constructing post-carbon institutions: Assessing EU carbon reduction efforts through an institutional risk governance approach

    International Nuclear Information System (INIS)

    This paper examines three different governance approaches the European Union (EU) and Member States (MS) are relying on to reach a low carbon economy by 2050. Current governance literature explains the operational methods of the EU's new governance approach to reduce carbon emissions. However, the literature neglects to account for the perceived risks that inhibit the roll-out of new low carbon technology. This article, through a novel approach, uses a grounded theoretical framework to reframe traditional risk literature and provides a connection to governance literature in order to assess the ability of EU governance mechanisms to reduce carbon emissions. The empirical research is based on responses from European energy stakeholders who participated in a Delphi method discussion and in semi-structured interviews; these identified three essential requirements for carbon emissions to be reduced to near zero by 2050: (1) an integrated European energy network, (2) carbon pricing and (3) demand reduction. These features correspond to institutionalized responses by the EU and MS: the Agency for the Cooperation of Energy Regulators (ACER); European Union Emission Trading Scheme (EU ETS) and energy efficiency directives and policies integrated into existing MS institutions. The theoretical and empirical findings suggest that governance by facilitation (energy efficiency) fails to induce significant investment and new policy approaches and cannot be relied on to achieve requisite reductions in demand. Governance by negotiation (ACER) and governance by hierarchy (EU ETS) do reduce risks and may encourage the necessary technological uptake. The term ‘risk governance’ is used to explain the important role governance plays in reducing risks and advancing new technology and thereby lowering carbon emissions in the energy sector. - Highlights: ► This article assesses the role of EU institutions in reducing carbon emissions by 2050. ► Empirical research is based on Delphi

  15. 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

  16. 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.

  17. 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

  18. Implicit Coupling Approach for Simulation of Charring Carbon Ablators

    Science.gov (United States)

    Chen, Yih-Kanq; Gokcen, Tahir

    2013-01-01

    This study demonstrates that coupling of a material thermal response code and a flow solver with nonequilibrium gas/surface interaction for simulation of charring carbon ablators can be performed using an implicit approach. The material thermal response code used in this study is the three-dimensional version of Fully Implicit Ablation and Thermal response program, which predicts charring material thermal response and shape change on hypersonic space vehicles. The flow code solves the reacting Navier-Stokes equations using Data Parallel Line Relaxation method. Coupling between the material response and flow codes is performed by solving the surface mass balance in flow solver and the surface energy balance in material response code. Thus, the material surface recession is predicted in flow code, and the surface temperature and pyrolysis gas injection rate are computed in material response code. It is demonstrated that the time-lagged explicit approach is sufficient for simulations at low surface heating conditions, in which the surface ablation rate is not a strong function of the surface temperature. At elevated surface heating conditions, the implicit approach has to be taken, because the carbon ablation rate becomes a stiff function of the surface temperature, and thus the explicit approach appears to be inappropriate resulting in severe numerical oscillations of predicted surface temperature. Implicit coupling for simulation of arc-jet models is performed, and the predictions are compared with measured data. Implicit coupling for trajectory based simulation of Stardust fore-body heat shield is also conducted. The predicted stagnation point total recession is compared with that predicted using the chemical equilibrium surface assumption

  19. 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

  20. Simulation of Enhanced Heavy Oil Recovery: History Match of Waterflooding and Polymer injection at Adverse Mobility Ratio

    OpenAIRE

    Al-Sawafi, Marwan Sulaiman Mohammed

    2015-01-01

    Waterflooding and polymer flooding total recovery in the unstable immiscible displacement is very attractive and its applications are interesting in recent years. However, the simulation models of unstable immiscible flooding are not well understood and need more investigations and studies. The conventional method to simulate polymer flooding is to history match the waterflooding and uses relative permeability in addition to the bulk polymer rheology to predict t...

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  5. 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...

  6. 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.

  7. A diagonal approach for the catalytic transformation of carbon dioxide

    International Nuclear Information System (INIS)

    Emissions of carbon dioxide are growing with the massive utilization of hydrocarbons for the production of energy and chemicals, resulting in a threatening global warming. The development of a more sustainable economy is urging to reduce the fingerprint of our current way of life. In this perspective, the organic chemistry industry will face important challenges in the next decades to replace hydrocarbons as a feedstock and use carbon-free energy sources. To tackle this challenge, new catalytic processes have been designed to convert CO2 to high energy and value-added chemicals (formamides, N-heterocycles and methanol), using a novel diagonal approach. The energy efficiency of the new transformations is ensured by the utilization of mild reductants such as hydro-silanes and hydro-boranes. Importantly the reactions are promoted by organic catalysts, which circumvent the problems of cost, abundance and toxicity usually encountered with metal complexes. Based on theoretical and experimental studies, the understanding of the mechanisms involved in these reactions allowed the rational optimization of the catalysts as well as the reaction conditions, in order to match the requirements of sustainable chemistry. (author)

  8. Climate change and JI options for India - a carbon-sink approach

    International Nuclear Information System (INIS)

    Three approaches to producing carbon dioxide arising from the Framework Convention on Climate Change are discussed. These are emission cap approach, fiscal or carbon tax and joint implementation. These are examined from an Indian perspective. More work on the economic, sociological and political aspects is recommended. (UK)

  9. 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.

  10. 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 may...... increased. On the other hand, more energy for the pressure drop is required to maintain a constant flow rate. These effects are studied within a new upscaling model developed previously (Zhang et al., 2011). In a communicating layer cake reservoir, higher end-point mobility ratio (water to oil) leads to...

  11. 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.

  12. A facile hydrothermal approach for construction of carbon coating on TiO2 nanoparticles

    Science.gov (United States)

    Olurode, Kehinde; Neelgund, Gururaj M.; Oki, Aderemi; Luo, Zhiping

    2012-04-01

    Herein a facile hydrothermal approach is used to construct carbon coated TiO2 nanoparticles employing dextrose as the source of carbon. The procedure is operated at a low temperature of 200 °C. Fourier infrared spectroscopy demonstrated the successful coating of carbon on TiO2 nanoparticles. The phase composition of TiO2 and carbon coated TiO2 nanoparticles were studied using X-ray diffraction and the surface morphology was analyzed by scanning and transmission electron microscopy. The existence of carbon coating on TiO2 nanoparticles was revealed by thermogravimetric analysis through different thermograms exhibited for TiO2 and carbon coated TiO2 nanoparticles. The reported method offers a simple and efficient approach for production of carbon coated TiO2 nanoparticles.

  13. 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...

  14. Carbon reaction with levitated silicon - Experimental and thermodynamic approaches

    Energy Technology Data Exchange (ETDEWEB)

    Beaudhuin, M., E-mail: mickael.beaudhuin@univ-montp2.fr [SIMAP EPM, UMR-CNRS 5266, 1340 rue de la piscine, F-38402 Saint Martin d' Heres Cedex (France); ICGM C2M, UMR-CNRS 5253, Place Eugene Bataillon, Bat 15 CC1504, F-34095 Montpellier Cedex (France); Chichignoud, G.; Bertho, P.; Duffar, T. [SIMAP EPM, UMR-CNRS 5266, 1340 rue de la piscine, F-38402 Saint Martin d' Heres Cedex (France); Lemiti, M. [Universite de Lyon, INL, UMR-CNRS 5270, INSA de Lyon, Bat. 502, 20 Av. Albert Einstein, F-69621 Villeurbanne Cedex (France); Zaidat, K. [SIMAP EPM, UMR-CNRS 5266, 1340 rue de la piscine, F-38402 Saint Martin d' Heres Cedex (France)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Interaction of methane with levitated silicon at high temperature. Black-Right-Pointing-Pointer Silicon nucleation undercooling decreases when the carbon concentration increases. Black-Right-Pointing-Pointer Experimental and thermodynamical calculation shows remarkable similar behavior. - Abstract: Metallurgical grade silicon (MG-Si) has become a new source of raw material for the photovoltaic industry. The use of this material as an alternative feed stock has however introduced phenomena that are detrimental to both the yield of the manufacturing process and the performance of the photovoltaic cells produced. This is mainly related to the presence of carbon, which precipitates to silicon carbide (SiC) in the ingot. This article focuses on the effect of carbon on silicon nucleation. Statistical experimental results of silicon nucleation are obtained as a function of carbon concentration and are presented and compared to thermodynamic calculations.

  15. Carbon reaction with levitated silicon – Experimental and thermodynamic approaches

    International Nuclear Information System (INIS)

    Highlights: ► Interaction of methane with levitated silicon at high temperature. ► Silicon nucleation undercooling decreases when the carbon concentration increases. ► Experimental and thermodynamical calculation shows remarkable similar behavior. - Abstract: Metallurgical grade silicon (MG-Si) has become a new source of raw material for the photovoltaic industry. The use of this material as an alternative feed stock has however introduced phenomena that are detrimental to both the yield of the manufacturing process and the performance of the photovoltaic cells produced. This is mainly related to the presence of carbon, which precipitates to silicon carbide (SiC) in the ingot. This article focuses on the effect of carbon on silicon nucleation. Statistical experimental results of silicon nucleation are obtained as a function of carbon concentration and are presented and compared to thermodynamic calculations.

  16. Modelling soil carbon flows and stocks following a carbon balance approach at regional scale for the EU-27

    Science.gov (United States)

    Lesschen, Jan Peter; Sikirica, Natasa; Bonten, Luc; Dibari, Camilla; Sanchez, Berta; Kuikman, Peter

    2014-05-01

    Soil Organic Carbon (SOC) is a key parameter to many soil functions and services. SOC is essential to support water retention and nutrient buffering and mineralization in the soil as well as to enhance soil biodiversity. Consequently, loss of SOC or low SOC levels might threaten soil productivity or even lead to a collapse of a farming system. Identification of areas in Europe with critically low SOC levels or with a negative carbon balance is a challenge in order to apply the appropriate strategies to restore these areas or prevent further SOC losses. The objective of this study is to assess current soil carbon flows and stocks at a regional scale; we follow a carbon balance approach which we developed within the MITERRA-Europe model. MITERRA-Europe is an environmental impact assessment model and calculates nitrogen and greenhouse emission on a deterministic and annual basis using emission and leaching factors at regional level (NUTS2, comparable to province level) in the EU27. The model already contained a soil carbon module based on the IPCC stock change approach. Within the EU FP7 SmartSoil project we developed a SOC balance approach, for which we quantified the input of carbon (manure, crop residues, other organic inputs) and the losses of carbon (decomposition, leaching and erosion). The calculations rules from the Roth-C model were used to estimate SOC decomposition. For the actual soil carbon stocks we used the data from the LUCAS soil sample survey. LUCAS collected soil samples in 2009 at about 22000 locations across the EU, which were analysed for a range of soil properties. Land management practices are accounted for, based on data from the EU wide Survey on Agricultural Production Methods in the 2010 Farm Structure Survey. The survey comprises data on the application of soil tillage, soil cover, crop rotation and irrigation. Based on the simulated soil carbon balance and the actual carbon stocks from LUCAS we now can identify regions within the EU that

  17. 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.

  18. 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

  19. 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.

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

    International Nuclear Information System (INIS)

    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

  1. New Characterisation Approaches for Carbon Ionic Liquid Electrodes (CILES)

    Czech Academy of Sciences Publication Activity Database

    Mikysek, T.; Stočes, M.; Švancara, I.; Vytřas, K.; Ludvík, Jiří

    Ústí nad Labem : BEST servis, 2012 - (Navrátil, T.; Fojta, M.), s. 77-81 ISBN 978-80-905221-0-7. [Moderní elektrochemické metody /32./. Jetřichovice (CZ), 21.05.2012-25.05.2012] Institutional support: RVO:61388955 Keywords : carbon * paste * electrode Subject RIV: CG - Electrochemistry

  2. Using LMDI approach to analyze changes in carbon dioxide emissions of China’s logistics industry

    Directory of Open Access Journals (Sweden)

    Ying Dai

    2015-05-01

    Full Text Available Purpose: China is confronting with tremendous pressure in carbon emission reduction. While logistics industry seriously relies on fossil fuel, and emits greenhouse gas, especially carbon dioxide. The aim of this article is to estimate the carbon dioxide emission in China’s logistics sector, and analyze the causes for the change of carbon dioxide emission, and identify the critical factors which mainly drive the change in carbon dioxide emissions of China’s logistics industry. Design/methodology/approach: The logarithmic mean Divisia index (LMDI method has often been used to analyze decomposition of energy consumption and carbon emission due to its theoretical foundation, adaptability, ease of use and result interpretation. So we use the LMDI method to analyze the changes in carbon dioxide emission in China’s logistics industry in this paper. Findings: By analyzing carbon dioxide emission of China’s logistics, the results show that the carbon dioxide emission of logistics in China has increased by 21.5 times, from 45.1 million tons to 1014.1 million tons in the research period. The highway transport is the main contributor to carbon dioxide emission in logistics industry. The energy intensity and carbon dioxide emission factors were contributing to the reduction of carbon dioxide emission in China’s logistics industry in overall study period. Originality/value: Although there are a lot of literature analyzed carbon dioxide emission in many industry sectors, for example manufacturing, iron and steel , pulp and paper, cement, glass industry, and so on. However, few scholars researched on carbon dioxide emission in logistics industry. This the first study is in the context of carbon dioxide emission of China’s logistics industry.

  3. 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.

  4. 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

  5. Enhanced oil recovery by improved waterflooding. Fourth annual report, October 1980-September 1981. [Illinois

    Energy Technology Data Exchange (ETDEWEB)

    Craig, F.F. III; Passman, F.J.; Burtch, F.W.

    1982-05-01

    Energy Resourcs Co. Inc., and its subcontractor Elf Aquitaine Oil and Gas Company are conducting a 100-acre pilot polymer flood in the Storms Pool Field near Carmi, in White County, Illinois. The project is a cost-sharing venture with the United States Department of Energy (DOE). Preparation for the polymer flood began in September 1977, and the project is scheduled for completion in December 1983. This report reviews progress during the fourth year of performance (October 1980 through September 1981). The Storms Pool, once highly productive, has yielded over 12 million barrels of oil from the Waltersburg formation since its discovery in 1939. The field has been waterflooded for over 20 years and is now largely in stripper production with high watercuts at most producing wells. Material balance and recent electric logs indicate, however, that there is a substantial volume of movable oil still in place, presumably bypassed by the inefficient waterflood. The polymer flood is intended to improve the sweep efficiency, showing that the engineering, management, and financial resources required for such tertiary techniques can be applied to similar fields that might otherwise be abandoned for lack of investment by parties knowledgeable in enhanced oil technology. Preflush injection and polymer injection were both initiated during this period with total polymer injection now standing at 179,453 barrels (or about 6% pore volume). Laboratory testing has continued throughout the year with the emphasis being on field support (troubleshooting field problems and monitoring the field injection and production systems). No evidence of polymer break-through has been detected at the production wells. Details of the interference testing program and the radiotracer study executed during this period are also presented.

  6. 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.

  7. 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

  8. 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.

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

    DEFF Research Database (Denmark)

    Petersen, Bjørn 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 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...

  10. 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.

  11. 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

  12. 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...

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

    OpenAIRE

    Al-Shalabi, Emad W.; Ghosh, B

    2016-01-01

    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. T...

  14. 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

  15. 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

  16. Multi proxy approach for the formation of calcium carbonates in alkaline man-made environments

    Science.gov (United States)

    Rinder, T.; Dietzel, M.; Leis, A.

    2009-04-01

    The formation of calcium carbonates, e.g. in drainage systems of tunnels, may be induced by degassing of CO2-rich groundwater which enters the building. However, the dissolution of portlandite (Ca(OH)2) from cements or the shotcrete of the tunnel wall bears an additional and immense potential for the formation of carbonates from alkaline solutions. Variations in trace element incorporation and distribution of the stable isotopes of carbon and oxygen in the precipitated calcium carbonates may represent powerful tools to identify individual mechanisms for carbonate formation. As portlandite dissolves, highly alkaline solutions are obtained. In this case, precipitation of calcium carbonate can be related to the absorption of CO2 from the atmosphere. Isotopic analyses of the calcite show that fixation of CO2 from the Earth's atmosphere leads to significantly lighter ^13Ccalcite values (down to -25 o/oo, VPDB) as expected for the fixation of groundwater carbonate (typical ^13Ccalcite values between -10 and -16o/oo, VPDB). The evolution of Sr/Ca ratios in the alkaline drainage solutions and in the corresponding calcium carbonate precipitation provides insight into the dissolution process at the concrete with respect to the amount of primarily dissolved portlandite from the cement. Moreover, an inverse relationship between Mg/Ca and Sr/Ca ratios is observed due to the liberation of aqueous strontium by the dissolution of portlandite and the formation of brucite (Mg(OH)2) at alkaline conditions. Less incorporation of magnesium in the calcite structure is a strong indicator for carbonate precipitation from highly alkaline environments. Applications of such multi proxy approaches are discussed with case studies. Main tasks are the reconstruction of the environmental conditions during primary CaCO3 formation and monitoring of ongoing precipitation of calcium carbonates and cement-water interaction in alkaline man-made environments.

  17. 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

  18. 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.

  19. 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

  20. 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...

  1. 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...

  2. Towards an integrated, multiple constraint approach. Assessing the regional carbon balance

    International Nuclear Information System (INIS)

    Full carbon accounting for regions as a whole, considering all fluxes and transports, is ultimately the only real hope if we are to manage global CO2 emissions. Many methods exist to estimate parts of the carbon budget, but none is yet available to measure carbon fluxes directly at regional scales. Atmospheric Boundary-Layer budgeting methods do have this potential. In the winter of 2000, an international workshop was held in Gubbio, Italy, to discuss ways to advance from the pilot experiments that have been carried out on these methods. First, the meeting helped to advance the methodology and clarify its objectives, requirements and merits. But more importantly, the outcome of the meeting was that atmospheric budget methods should be part of an integrative approach, in which data and model results of very different kinds and from very different scales all provide constraints for estimating the net carbon exchange of a region. Several international projects are now operating to achieve this goal

  3. 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

  4. 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 ...

  5. 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.

  6. Comparison of microbial community compositions of injection and production well samples in a long-term water-flooded petroleum reservoir.

    Directory of Open Access Journals (Sweden)

    Hong-Yan Ren

    Full Text Available Water flooding plays an important role in recovering oil from depleted petroleum reservoirs. Exactly how the microbial communities of production wells are affected by microorganisms introduced with injected water has previously not been adequately studied. Using denaturing gradient gel electrophoresis (DGGE approach and 16S rRNA gene clone library analysis, the comparison of microbial communities is carried out between one injection water and two production waters collected from a working block of the water-flooded Gudao petroleum reservoir located in the Yellow River Delta. DGGE fingerprints showed that the similarities of the bacterial communities between the injection water and production waters were lower than between the two production waters. It was also observed that the archaeal composition among these three samples showed no significant difference. Analysis of the 16S rRNA gene clone libraries showed that the dominant groups within the injection water were Betaproteobacteria, Gammaproteobacteria and Methanomicrobia, while the dominant groups in the production waters were Gammaproteobacteria and Methanobacteria. Only 2 out of 54 bacterial operational taxonomic units (OTUs and 5 out of 17 archaeal OTUs in the injection water were detected in the production waters, indicating that most of the microorganisms introduced by the injection water may not survive to be detected in the production waters. Additionally, there were 55.6% and 82.6% unique OTUs in the two production waters respectively, suggesting that each production well has its specific microbial composition, despite both wells being flooded with the same injection water.

  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. Examining carbon emissions economic growth nexus for India: A multivariate cointegration approach

    International Nuclear Information System (INIS)

    The study probes cointegration and causality between carbon emissions and economic growth for India using ARDL bounds testing approach complemented by Johansen-Juselius maximum likelihood procedure in a multivariate framework by incorporating energy supply, investment and employment for time span 1971-2006. The study fails to establish long-run equilibrium relationship and long term causality between carbon emissions and economic growth; however, there exists a bi-directional short-run causality between the two. Hence, in the short-run, any effort to reduce carbon emissions could lead to a fall in the national income. This study also establishes unidirectional short-run causality running from economic growth to energy supply and energy supply to carbon emissions. The absence of causality running from energy supply to economic growth implies that in India, energy conservation and energy efficiency measures can be implemented to minimize the wastage of energy across value chain. Such measures would narrow energy demand-supply gap. Absence of long-run causality between carbon emissions and economic growth implies that in the long-run, focus should be given on harnessing energy from clean sources to curb carbon emissions, which would not affect the country's economic growth.

  10. Drought Impact on Water - Carbon Interaction in Soil: A Stable Isotopic Approach

    Science.gov (United States)

    Joseph, J.; Weiler, M.; Gessler, A.

    2014-12-01

    Extreme climatic conditions like drought introduce drastic changes in carbon and water dynamics in the plant - soil continuum, starting from carbon assimilation till carbon allocation in the soil, root water uptake till transpiration via leaves. Our objective was to study the drought impact on the dynamics of Carbon, and water cycles, as well as the interaction between them under extreme climatic conditions in the plant soil continuum. The first phase of the experiment involved 13CO2 pulse labeling of drought exposed and well-water beech microcosms, during which we monitored the 13C allocation to roots, and in the soil by measuring the CO2 concentration, ∂13C, and ∂18O of root derived CO2. We found that drought had a significant impact on, a) carbon assimilation, allocation, and translocation rate in the plant - soil system. The drought stressed plants not only assimilated fewer amounts of CO2, but also translocation of those assimilates belowground was extremely slow, and root respiration was low in comparison the well watered control plants. The second phase involved rewetting of the drought chambers (and the application of similar amounts of water to the controls) using D218O enriched water followed by an additional 13CO2 pulse labeling approach so as to study the effects of drought on the infiltration patterns of a precipitation event as well as the recovery of the carbon relations of previously drought stressed beech saplings.

  11. A hybrid modelling approach to develop scenarios for China's carbon dioxide emissions to 2050

    International Nuclear Information System (INIS)

    This paper describes a hybrid modelling approach to assess the future development of China's energy system, for both a “hypothetical counterfactual baseline” (HCB) scenario and low carbon (“abatement”) scenarios. The approach combines a technology-rich integrated assessment model (MESSAGE) of China's energy system with a set of sector-specific, bottom-up, energy demand models for the transport, buildings and industrial sectors developed by the Grantham Institute for Climate Change at Imperial College London. By exploring technology-specific solutions in all major sectors of the Chinese economy, we find that a combination of measures, underpinned by low-carbon power options based on a mix of renewables, nuclear and carbon capture and storage, would fundamentally transform the Chinese energy system, when combined with increasing electrification of demand-side sectors. Energy efficiency options in these demand sectors are also important. - Highlights: • Combining energy supply and demand models reveals low-carbon technology choices across China's economy. • China could reduce its CO2 emissions to close to 3 Gt in 2050, costing around 2% of GDP. • Decarbonising the power sector underpins the energy system transformation. • Electrification of industrial processes, building heating and transport is required. • Energy efficiency across the demand side is also important

  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. Optical approaches to examining the dynamics of dissolved organic carbon in optically complex inland waters

    International Nuclear Information System (INIS)

    Optical approaches were developed to examine the relationship between the optically active and the optically inactive fractions of dissolved organic carbon in inland waters. A multiple linear regression model was developed on the basis of an extensive dataset from Taihu Lake, and validated employing data from another large shallow eutrophic lake (Chaohu Lake) in southern China. The model was used to estimate the concentration of dissolved organic matter (n = 191) using the absorption characteristics of its chromophoric fraction with a high correlation coefficient (R2 = 0.62) and a low root mean squared error (RMSE = 9.67%). This intra-ecosystem validity allows us to improve our understanding of carbon dynamics using optical remote sensing approaches for these optically complex lakes, where multiple sources and sinks of dissolved organic matter were present. (letter)

  14. Coupled mode space approach for the simulation of realistic carbon nanotube field-effect transistors

    OpenAIRE

    Fiori, Gianluca; Iannaccone, Giuseppe; Klimeck, Gerhard

    2007-01-01

    A coupled mode space approach within the nonequiibriurn Green's function formalism is presented, which allows to perform simulations of realistic carbon nanotube field-effect transistors (CNT-FETs) with no spatial symmetry. Computing :time is significantly reduced with respect to the real space ap)roach, since only few modes are needed in order to obtain accurate results. The advantage of the method increases with increasing nanotube diameter, and is a factor of 20 in computing time for a (25...

  15. Pulse-induced nonequilibrium dynamics of acetylene inside carbon nanotube studied by an ab initio approach

    OpenAIRE

    Y. Miyamoto; Zhang, H.; Rubio, A.

    2012-01-01

    Nanoscale molecular confinement substantially modifies the functionality and electronic properties of encapsulated molecules. Many works have approached this problem from the perspective of quantifying ground-state molecular changes, but little is known about the nonequilibrium dynamics of encapsulated molecular system. In this letter, we report an analysis of the nonequilibrium dynamics of acetylene (C2H2) inside a semiconducting carbon nanotube (CNT). An ultrashort high-intense laser pulse ...

  16. 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...

  17. 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. PMID:25746761

  18. 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.

  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. 3D geomodelling and flow simulation of the Late Devonian Bakken Formation in south-central Saskatchewan : case study : Smiley Buffalo heavy oil waterflood

    Energy Technology Data Exchange (ETDEWEB)

    Mohr, R.; Estrada, C.A.; Norrena, K. [Society of Petroleum Engineers, Richardson, TX (United States)]|[Nexen Inc., Calgary, AB (Canada)

    2005-11-01

    The Smiley Buffalo field in southern Saskatchewan is a mature heavy oil reservoir where reservoir management has been challenged by complex geological features. The primary reservoir is the middle Bakken sandstone which was deposited as an offshore sand ridge in late Devonian to early Mississippian period. The greatest challenge is that the reservoir sits above a carbonate formation that was subjected to post depositional erosion and karstification. Conduits for out-of-zone water infiltration were created by fracture networks that were generated during the structural deformation. These features influence reservoir performance. A newly constructed geomodel was used to simulate flow and to identify areas of missed opportunity. The method used to characterize the reservoir and predict reservoir behaviour was presented in an effort to optimize a heavy oil waterflood project. The geological model was described followed by a geocellular model and flow simulation. A facies classification model was derived with fuzzy logic which used the core and log data along with the geologic model. Sequential indicator simulation was used to augment the structural model with facies information, while sequential Gaussian simulation was used to augment the petrophysical properties. Flow simulation and well location selection were determined from these representative models. The complexity of the 3 dimensional facies and property modeling in the flow simulation was reflected in the amount of changes needed to reach a history match. These changes included the oil-water contact in sinkholed areas within defined limits, relative permeability end points of facies 2, vertical to horizontal permeability ratios of the same rock type, and negative skin factor. The additional property modeling was justified by the excellent results obtained in the history matching process. The results are being used for reservoir management decisions. 10 refs., 4 tabs., 38 figs.

  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. NMR relaxation of neritic carbonates: An integrated petrophysical and petrographical approach

    Science.gov (United States)

    Vincent, Benoit; Fleury, Marc; Santerre, Yannick; Brigaud, Benjamin

    2011-05-01

    A set of carbonate outcrop samples, covering a wide range of the sedimentary textures and depositional environments existing on carbonate systems, was studied through an integrated petrographical and petrophysical approach. With the aim of improving the understanding of the NMR (Nuclear Magnetic Resonance) signal of carbonates, this work is: 1) providing an atlas for various carbonate reservoir rock-types, 2) providing a workflow for integrating geological and petrophysical data and, 3) documenting common shortfalls in NMR/MICP analyses in carbonates. The petrographical investigation includes thin section and SEM (Secondary Electron Microscope) observations, whereas petrophysical investigation includes porosity (Φ), permeability (K), NMR, MICP (Mercury Injection Capillary Pressure), and specific surface area (BET) measurements. On the basis of NMR and MICP data, 4 groups of samples were identified: (1) microporous samples, (2) micro-mesoporous samples, (3) wide multimodal samples, and (4) atypical samples. The microporous samples allow us to define a maximum NMR threshold for microporosity at a T 2 of 200 ms. NMR and MICP response of the investigated carbonates are often comparable in terms of modal distribution (microporous, micro-mesoporous and wide multimodal samples). In particular, micritization, a well known but underestimated early diagenetic process, tends to homogenize the NMR signal of primarily different sedimentary facies. A grainstone with heavily micritized grains can display well sorted unimodal NMR and MICP signatures very similar, even identical, to a mudstone-wackestone. Their signatures are comparable to that of a simple sphere packing model. On the contrary, several samples (labeled atypical samples) show a discrepancy between NMR and MICP response. This discrepancy is explained by the fact that MICP can be affected by the physical connectivity of the pore network, in case of disseminated and isolated molds in a micrite matrix for instance

  3. 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

  4. 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.

  5. A Two-Step Hydrothermal Synthesis Approach to Monodispersed Colloidal Carbon Spheres

    Directory of Open Access Journals (Sweden)

    Yu Aibing

    2009-01-01

    Full Text Available Abstract This work reports a newly developed two-step hydrothermal method for the synthesis of monodispersed colloidal carbon spheres (CCS under mild conditions. Using this approach, monodispersed CCS with diameters ranging from 160 to 400 nm were synthesized with a standard deviation around 8%. The monomer concentration ranging from 0.1 to 0.4 M is in favor of generation of narrower size distribution of CCS. The particle characteristics (e.g., shape, size, and distribution and chemical stability were then characterized by using various techniques, including scanning electron microscopy (SEM, FT-IR spectrum analysis, and thermalgravity analysis (TGA. The possible nucleation and growth mechanism of colloidal carbon spheres were also discussed. The findings would be useful for the synthesis of more monodispersed nanoparticles and for the functional assembly.

  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. 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

  8. 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.

  9. 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.

  10. 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

  11. A regression modeling approach for studying carbonate system variability in the northern Gulf of Alaska

    Science.gov (United States)

    Evans, Wiley; Mathis, Jeremy T.; Winsor, Peter; Statscewich, Hank; Whitledge, Terry E.

    2013-01-01

    AbstractThe northern Gulf of Alaska (GOA) shelf experiences carbonate system variability on seasonal and annual time scales, but little information exists to resolve higher frequency variability in this region. To resolve this variability using platforms-of-opportunity, we present multiple linear regression (MLR) models constructed from hydrographic data collected along the Northeast Pacific Global Ocean Ecosystems Dynamics (GLOBEC) Seward Line. The empirical algorithms predict dissolved inorganic carbon (DIC) and total alkalinity (TA) using observations of nitrate (NO3-), temperature, salinity and pressure from the surface to 500 m, with R2s > 0.97 and RMSE values of 11 µmol kg-1 for DIC and 9 µmol kg-1 for TA. We applied these relationships to high-resolution NO3- data sets collected during a novel 20 h glider flight and a GLOBEC mesoscale SeaSoar survey. Results from the glider flight demonstrated time/space along-isopycnal variability of aragonite saturations (Ωarag) associated with a dicothermal layer (a cold near-surface layer found in high latitude oceans) that rivaled changes seen vertically through the thermocline. The SeaSoar survey captured the uplift to GOA. This work is similar to recent studies aimed at predicting the carbonate system in continental margin settings, albeit demonstrates that a NO3--based approach can be applied to high-latitude data collected from platforms capable of high-frequency measurements.

  12. Lagrangian Approach to Jet Mixing and Optimization of the Reactor for Production of Carbon Nanotubes

    Science.gov (United States)

    Povitsky, Alex; Salas, Manuel D.

    2001-01-01

    This study was motivated by an attempt to optimize the High Pressure carbon oxide (HiPco) process for the production of carbon nanotubes from gaseous carbon oxide, The goal is to achieve rapid and uniform heating of catalyst particles by an optimal arrangement of jets. A mixed Eulerian and Lagrangian approach is implemented to track the temperature of catalyst particles along their trajectories as a function of time. The FLUENT CFD software with second-order upwind approximation of convective terms and an algebraic multigrid-based solver is used. The poor performance of the original reactor configuration is explained in terms of features of particle trajectories. The trajectories most exposed to the hot jets appear to be the most problematic for heating because they either bend towards the cold jet interior or rotate upwind of the mixing zone. To reduce undesirable slow and/or oscillatory heating of catalyst particles, a reactor configuration with three central jets is proposed and the optimal location of the central and peripheral nozzles is determined.

  13. 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.

  14. Effects of cryptogamic covers on the global carbon and nitrogen balance as investigated by different approaches

    Science.gov (United States)

    Weber, Bettina; Porada, Philipp; Elbert, Wolfgang; Burrows, Susannah; Caesar, Jennifer; Steinkamp, Jörg; Tamm, Alexandra; Andreae, Meinrat O.; Büdel, Burkhard; Kleidon, Axel; Pöschl, Ulrich

    2014-05-01

    Cryptogamic covers are composed of cyanobacteria, green algae, lichens, bryophytes, fungi and bacteria in varying proportions. As cryptogamic ground covers, comprising biological soil and rock crusts they occur on many terrestrial ground surfaces. Cryptogamic plant covers, containing epiphytic and epiphyllic crusts as well as foliose or fruticose lichens and bryophytes spread over large portions of terrestrial plant surfaces. Photoautotrophic organisms within these crusts sequester atmospheric CO2 and many of them include nitrogen-fixing cyanobacteria, utilizing atmospheric N2 to form ammonium which can be readily used by vascular plants. In a large-scale data analysis approach, we compiled all available data on the physiological properties of cryptogamic covers and developed a model to calculate their annual nitrogen fixation and net primary production. Here, we obtained a total value of 3.9 Pg a-1 for the global net uptake of carbon by cryptogamic covers, which corresponds to approximately 7% of the estimated global net primary production of terrestrial vegetation. Nitrogen assimilation of cryptogamic covers revealed a global estimate of ~49 Tg a-1, accounting for as much as about half the estimated total terrestrial biological nitrogen fixation. In a second approach, we calculated the global carbon uptake by lichens and bryophytes by means of a process-based model. In this model, we used gridded climate data combined with key habitat properties (as e.g. disturbance intervals) to predict the processes which control net carbon uptake, i.e. photosynthesis, respiration, water uptake and evaporation. The model relies on equations frequently used in dynamic vegetation models, which were combined with concepts specific to lichens and bryophytes. As this model only comprises lichens and bryophytes, the predicted terrestrial net uptake of 0.34 to 3.3 Gt a-1 is in accordance with our empirically-derived estimate. Based on this result, we quantified the amount of nitrogen

  15. 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.

  16. 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.

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

    International Nuclear Information System (INIS)

    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 Hg2+ 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. • Hg2+ is most effectively sensed with a detection limit of 16.5 nM

  18. 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.

  19. 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

  20. An experimental design approach for modeling As(V) adsorption from aqueous solution by activated carbon.

    Science.gov (United States)

    Bakkal Gula, C; Bilgin Simsek, E; Duranoglu, D; Beker, U

    2015-01-01

    The present paper discusses response surface methodology as an efficient approach for predictive model building and optimization of As(V) adsorption on activated carbon derived from a food industry waste: peach stones. The objectives of the study are application of a three-factor 2³ full factorial and central composite design technique for maximizing As(V) removal by produced activated carbon, and examination of the interactive effects of three independent variables (i.e., solution pH, temperature, and initial concentration) on As(V) adsorption capacity. Adsorption equilibrium was investigated by using Langmuir, Freundlich, and Dubinin-Radushkevich isotherm models. First-order and second-order kinetic equations were used for modeling of adsorption kinetics. Thermodynamic parameters (ΔG °, ΔH °, and ΔS °) were calculated and used to explain the As(V) adsorption mechanism. The negative value of ΔH (-7.778 kJ mol⁻¹) supported the exothermic nature of the sorption process and the Gibbs free energy values (ΔG°) were found to be negative, which indicates that the As(V) adsorption is feasible and spontaneous. PMID:25633943

  1. 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

  2. Synthetic approach from polypyrrole nanotubes to nitrogen doped pyrolyzed carbon nanotubes for asymmetric supercapacitors

    Science.gov (United States)

    Dubal, Deepak P.; Chodankar, Nilesh R.; Caban-Huertas, Zahilia; Wolfart, Franciele; Vidotti, Marcio; Holze, Rudolf; Lokhande, Chandrakant D.; Gomez-Romero, Pedro

    2016-03-01

    Pseudocapacitive materials are highly capable to achieve high energy density integrated with high power electrostatic capacitive materials. However, finding a suitable electrostatic capacitive material to integrate with pseudocapacitive material in order to achieve high energy density with good rate capability is still a challenge. Herein, we are providing a novel synthetic approach starting from the synthesis of polypyrrole nanotubes (PPy-NTs) and ending up at the carbonization of PPy-NTs to obtain N-doped carbon nanotubes (N-CNTs). With highly porous nature of PPy-NTs and great graphitic texture with copious heteroatom functionalities, N-CNTs significantly promoted the faradic pseudo-capacitors, demonstrating high single-electrode capacitance over 332 F/g(PPy-NTs) and 228 F/g(N-CNTs) in 1 M H2SO4 aqueous solution. Further, a novel asymmetric supercapacitor with PPy-NTs as positive and N-CNTs as negative electrode has been fabricated. This PPy-NTs//N-CNTs cell effectively provides high operation voltage (1.4 V) and hence high energy density over 28.95 W h/kg (0.41 mW h/cm3) with a high power density of 7.75 kW/kg (113 mW/cm3) and cyclic stability of 89.98% after 2000 cycles.

  3. Resting in peace?- regulatory approaches to the geological storage of radioactive waste and carbon dioxide

    International Nuclear Information System (INIS)

    An emerging and much heralded technology for fighting climate change by reducing anthropogenic greenhouse gas emissions is carbon capture and storage (CCS). The final stage of CCS is the storage (or disposal) of the carbon dioxide (CO2) away from the atmosphere, typically in a deep geological formation. Although the risks posed by CO2 differ from those presented by nuclear waste and spent fuel, the similarities - most noticeably the vast time scales involved and the preference for concentration and containment - make a comparison of regulatory approaches to such risks relevant and informative. The intention of the current paper is to carry out such a comparison. Using Sweden as a focal point, applicable legal frameworks for the management of captured CO2 and spent nuclear fuel and nuclear waste will be juxtaposed. Two aspects in particular will be chosen for closer scrutiny: requirements pertaining to the selection of sites for disposal/storage of nuclear material and captured CO2 respectively, and the nature and allocation of economic responsibility for handling and minimizing long-term hazards associated with those substances. In the case of nuclear residues, responsibility for spent fuel will be the main focus. However, the same principles mostly apply to other radioactive waste from the nuclear industry, such as parts of decommissioned nuclear reactors

  4. 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.

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

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Davis, Zachary James; Madsen, Dorte Nørgaard; Mølhave, Kristian; Bøggild, Peter; Rasmussen, Anne-Marie; Brorson, M.; Jacobsen, Claus J.H.; Boisen, Anja

    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 induced deposition of an organometallic compound. (C) 2004 Elsevier B.V. All rights reserved....

  6. A simplified modelling approach for quantifying tillage effects on soil carbon stocks

    DEFF Research Database (Denmark)

    Chatskikh, Dmitri; Hansen, Søren; Olesen, Jørgen E.;

    2009-01-01

    Soil tillage has been shown to affect long-term changes in soil organic carbon (SOC) content in a number of field experiments. This paper presents a simplified approach for including effects of tillage in models of soil C turnover in the tilled-soil layer. We used an existing soil organic matter...... (SOM) model (CN-SIM) with standard SOC data for a homogeneous tilled layer from four long-term field experiments with conventionally tilled (CT) and no-till (NT) treatments. The SOM model was tested on data from long-term (>10 years) field trials differing in climatic conditions, soil properties......, residue management and crop rotations in Australia, Brazil, the USA and Switzerland. The C input for the treatments was estimated using data on crop rotation and residue management. The SOM model was applied for both CT and NT trials without recalibration, but incorporated a 'tillage factor' (TF) to scale...

  7. Reviews and synthesis: Carbon capture and storage monitoring - an integrated biological, biophysical and chemical approach

    Science.gov (United States)

    Hicks, N.; Vik, U.; Taylor, P.; Ladoukakis, E.; Park, J.; Kolisis, F.; Stahl, H.; Jakobsen, K. S.

    2015-06-01

    Carbon capture and storage (CCS) is a developing technology that seeks to mitigate against the impact of increasing anthropogenic carbon dioxide (CO2) production by capturing CO2 from large point source emitters. After capture the CO2 is compressed and transported to a reservoir where it is stored for geological time scales. Potential leakages from CCS projects, where stored CO2 migrates through the overlaying sediments, are likely to have severe implications on benthic and marine ecosystems. Nonetheless, prokaryotic response to elevated CO2 concentrations has been suggested as one of the first detectable warnings if a CO2 leakage should occur. Applying properties of prokaryotic communities (i.e. community composition and metabolic status) as a novel CO2 monitoring application is highly reliable within a multidisciplinary framework, where deviations from the baseline can easily be identified. In this paper we review current knowledge about the impact of CO2 leakages on marine sediments from a multidisciplinary-based monitoring perspective. We focus on aspects from the fields of biology, geophysics, and chemistry, and discuss a case study example. We argue the importance of an integrative multidisciplinary approach, incorporating biogeochemistry, geophysics, microbial ecology and modelling, with a particular emphasis on metagenomic techniques and novel bioinformatics, for future CCS monitoring. Within this framework, we consider that an effective CCS monitoring programme will ensure that large-scale leakages with potentially devastating effects for the overlaying ecosystem are avoided. Furthermore, the multidisciplinary approach suggested here for CCS monitoring is generic, and can be adapted to other systems of interest.

  8. Using LMDI approach to analyze changes in carbon dioxide emissions of China’s logistics industry

    OpenAIRE

    Ying Dai; Jing Zhu; Han Song

    2015-01-01

    Purpose: China is confronting with tremendous pressure in carbon emission reduction. While logistics industry seriously relies on fossil fuel, and emits greenhouse gas, especially carbon dioxide. The aim of this article is to estimate the carbon dioxide emission in China’s logistics sector, and analyze the causes for the change of carbon dioxide emission, and identify the critical factors which mainly drive the change in carbon dioxide emissions of China’s logistics industry. Design/methodolo...

  9. Small forests owners and environmental sustainability in Guatemala: The potential of the Carbon Banking approach

    OpenAIRE

    Garcia-Barrios, Fernando; Bigsby, Hugh R.; Kerr, Geoffrey N.

    2012-01-01

    Forest carbon is potentially an important income stream for small land owners in Guatemala that would help to cease deforestation and forest degradation pressures. However, the temporary nature of sequestered forest carbon, the risk of environmental disturbances releasing forest sequestered carbon, and the form of international carbon markets affect the ability of small forest owners to participate in carbon trading schemes. This paper reports the results of an investigation into the stabilit...

  10. 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

  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. 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

  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

    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......, e.g. the impact on phytoplankton dynamics and benthic-pelagic coupling, which can significantly contribute to the CO2 cycle. Therefore, an ecosystem approach that accounts for the trophic interactions of bivalve aquaculture, including dissolved and particulate organic and inorganic carbon cycling......, 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...

  16. 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...

  17. 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

  18. A model-based assessment of the TrOCA approach for estimating oceanic anthropogenic carbon

    Directory of Open Access Journals (Sweden)

    A. Yool

    2009-07-01

    Full Text Available The future behaviour of the global ocean as a sink for CO2 is significant for climate change, but it is also important to understand its past by quantifying anthropogenic CO2 (Cant in the ocean today. Unfortunately, this is complicated by the difficulty of deconvoluting Cant from the natural, unperturbed carbon cycle. Nonetheless, a range of techniques have been devised that perform this separation using the information implicit in other physical, biogeochemical and artificial ocean tracers. One such method is the TrOCA approach, whose parameterisation is derived from relationships between biogeochemical tracers within watermasses defined by age tracers such as CFC-11. TrOCA has a number of methodological advantages, and has been shown to be plausible, relative to other methods, in a number of studies. Here we examine the TrOCA approach by using it to deconvolute the known distribution of Cant from an ocean general circulation model (OGCM simulation of the industrial period (1864–2004. TrOCA is evaluated at local, regional and global scales, with an emphasis on the wider applicability of the parameterisations derived at these scales. Our work finds that the published TrOCA parameterisation performs poorly when extrapolated beyond its calibration region, either with observational data or (especially model output. Optimising TrOCA parameters using model output as a synthetic dataset leads to some small improvements, but the resulting TrOCA variants still perform poorly. Furthermore, there are large ranges on the optimised TrOCA parameters suggesting that a "universal" TrOCA parameterisation is not achieveable.

  19. Controlling wear failure of graphite-like carbon film in aqueous environment: Two feasible approaches

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yongxin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Wang Liping, E-mail: lpwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China); Xue Qunji [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Lanzhou 730000 (China)

    2011-02-15

    Friction and wear behaviors of graphite-like carbon (GLC) films in aqueous environment were investigated by a reciprocating sliding tribo-meter with ball-on-disc contact. Film structures and wear scars were studied by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and a non-contact 3D surface profiler. A comprehensive wear model of the GLC film in aqueous environment was established, and two feasible approaches to control critical factor to the corresponding wear failure were discussed. Results showed that wear loss of GLC films in aqueous environment was characterized by micro-plough and local delamination. Due to the significant material loss, local delamination of films was critical to wear failure of GLC film in aqueous environment if the film was not prepared properly. The initiation and propagation of micro-cracks within whole films closely related to the occurrence of the films delamination from the interface between interlayer and substrate. The increase of film density by adjusting the deposition condition would significantly reduce the film delamination from substrate, meanwhile, fabricating a proper interlayer between substrate and GLC films to prevent the penetration of water molecules into the interface between interlayer and substrate could effectively eliminate the delamination.

  20. 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)

  1. 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.

  2. 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

  3. SnO2-decorated multiwalled carbon nanotubes and Vulcan carbon through a sonochemical approach for supercapacitor applications.

    Science.gov (United States)

    Vinoth, Victor; Wu, Jerry J; Asiri, Abdullah M; Lana-Villarreal, Teresa; Bonete, Pedro; Anandan, Sambandam

    2016-03-01

    Multiwalled carbon nanotubes (MWCNTs) and Vulcan carbon (VC) decorated with SnO2 nanoparticles were synthesized using a facile and versatile sonochemical procedure. The as-prepared nanocomposites were characterized by means of transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infra red spectroscopy. It was evidenced that SnO2 nanoparticles were uniformly distributed on both carbon surfaces, tightly decorating the MWCNTs and VC. The electrochemical performance of the nanocomposites was evaluated by cyclic voltammetry and galvanostatic charge/discharge cycling. The as-synthesized SnO2/MWCNTs nanocomposites show a higher capacity than the SnO2/VC nanocomposites. Concretely, the SnO2/MWCNTs electrodes exhibit a specific capacitance of 133.33 F g(-1), whereas SnO2/VC electrodes exhibit a specific capacitance of 112.14 F g(-1) measured at 0.5 mA cm(-2) in 1 M Na2SO4. PMID:26585000

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

    Science.gov (United States)

    Jirsák, J; Škvor, J

    2015-05-20

    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. PMID:25923412

  5. 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)

  6. 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.

  7. A Mechanism-Based Approach to Predict the Relative Biological Effectiveness of Protons and Carbon Ions in Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: The physical and potential biological advantages of proton and carbon ions have not been fully exploited in radiation therapy for the treatment of cancer. In this work, an approach to predict proton and carbon ion relative biological effectiveness (RBE) in a representative spread-out Bragg peak (SOBP) is derived using the repair-misrepair-fixation (RMF) model. Methods and Materials: Formulas linking dose-averaged linear-quadratic parameters to DSB induction and processing are derived from the RMF model. The Monte Carlo Damage Simulation (MCDS) software is used to quantify the effects of radiation quality on the induction of DNA double-strand breaks (DSB). Trends in parameters α and β for clinically relevant proton and carbon ion kinetic energies are determined. Results: Proton and carbon ion RBE are shown to increase as particle energy, dose, and tissue α/β ratios decrease. Entrance RBE is ∼1.0 and ∼1.3 for protons and carbon ions, respectively. For doses in the range of 0.5 to 10 Gy, proton RBE ranges from 1.02 (proximal edge) to 1.4 (distal edge). Over the same dose range, the RBE for carbon ions ranges from 1.5 on the proximal edge to 6.7 on the distal edge. Conclusions: The proposed approach is advantageous because the RBE for clinically relevant particle distributions is guided by well-established physical and biological (track structure) considerations. The use of an independently tested Monte Carlo model to predict the effects of radiation quality on DSB induction also minimizes the number of ad hoc biological parameters that must be determined to predict RBE. Large variations in predicted RBE across an SOBP may produce undesirable biological hot and cold spots. These results highlight the potential for the optimization of physical dose for a uniform biological effect.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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)

  13. 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

  14. Theoretical study of the structure, energetics, and dynamics of silicon and carbon systems using tight-binding approaches

    International Nuclear Information System (INIS)

    Semiempirical interatomic potentials are developed for silicon and carbon by modeling the total energy of the system using tight-binding approaches. The parameters of the models were obtained by fitting to results from accurate first-principles Local Density Functional calculations. Applications to the computation of phonons as a function of volume for diamond-structured silicon and carbon and the thermal expansions for silicon and diamond yields results which agree well with experiment. The physical origin of the negative thermal expansion observed in silicon is explained. A tight-binding total energy model is generated capable of describing carbon systems with a variety of atomic coordinations and topologies. The model reproduces the total energy versus volume curves of various carbon polytypes as well as phonons and elastic constants of diamond and graphite. The model has also been used in the molecular-dynamics simulation of the properties of carbon clusters. The calculated ground-state geometries of small clusters (C2--C10) correlates well with results from accurate quantum chemical calculations, and the structural trend of clusters from C2 to C60 are investigated. 67 refs., 19 figs

  15. 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

  16. 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

  17. 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

  18. 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.

  19. Quantification of soil organic carbon sequestration potential in cropland: a model approach.

    Science.gov (United States)

    Qin, ZhangCai; Huang, Yao

    2010-07-01

    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 R (2) of 0.74 (n=19, Pcold, 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. PMID:20697876

  20. Projecting the release of carbon from permafrost soils using a perturbed parameter ensemble modelling approach

    Science.gov (United States)

    MacDougall, Andrew H.; Knutti, Reto

    2016-04-01

    The soils of the northern hemispheric permafrost region are estimated to contain 1100 to 1500 Pg of carbon. A substantial fraction of this carbon has been frozen and therefore protected from microbial decay for millennia. As anthropogenic climate warming progresses much of this permafrost is expected to thaw. Here we conduct perturbed model experiments on a climate model of intermediate complexity, with an improved permafrost carbon module, to estimate with formal uncertainty bounds the release of carbon from permafrost soils by the year 2100 and 2300 CE. We estimate that by year 2100 the permafrost region may release between 56 (13 to 118) Pg C under Representative Concentration Pathway (RCP) 2.6 and 102 (27 to 199) Pg C under RCP 8.5, with substantially more to be released under each scenario by the year 2300. Our analysis suggests that the two parameters that contribute most to the uncertainty in the release of carbon from permafrost soils are the size of the non-passive fraction of the permafrost carbon pool and the equilibrium climate sensitivity. A subset of 25 model variants are integrated 8000 years into the future under continued RCP forcing. Under the moderate RCP 4.5 forcing a remnant near-surface permafrost region persists in the high Arctic, eventually developing a new permafrost carbon pool. Overall our simulations suggest that the permafrost carbon cycle feedback to climate change will make a significant contribution to climate change over the next centuries and millennia, releasing a quantity of carbon 3 to 54 % of the cumulative anthropogenic total.

  1. 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.

  2. Assessment of potential increased oil production by polymer-waterflood in northern and southern mid-continent oil fields. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Pease, R.W.; Durham, E.N.; Watson, J.A.

    1979-09-01

    A conventional waterflood in the North Stanley Field, Osage County, Oklahoma, nearing the economic limit, was modified by substituting an aqueous solution of polyacrylamides for brine as the intected fluid. Remedial operations on existing facilities were performed before polymer injection began. Positive oil production response was achieved from this 1000-acre project, a maximum EOR production rate of about 200 barrels per day being achieved within 1-1/2 years after the start of polymer injection. Based on performance to January 1979, ultimate EOR recovery is estimated at 500,000 barrels.

  3. 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.

  4. 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...

  5. 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

    Low salinity water flooding is well studied for sandstone reservoirs, both laboratory and field tests have showed improvement in the oil recovery in many cases. Up to very recently, the low salinity effect has been indeterminated for carbonates. Most recently, Saudi Aramco reported that substanti...... light of experimental results, discussions are made about possible mechanisms for improving oil recovery in carbonate reservoir as a function of change in brine salinity. Copyright 2012, Society of Petroleum Engineers....

  6. Impact of dust deposition on carbon budget: a tentative assessment from a mesocosm approach

    OpenAIRE

    C. Guieu; Ridame, C.; E. Pulido-Villena; Bressac, M.; Desboeufs, K.; Dulac, F.

    2014-01-01

    By bringing new nutrients and particles to the surface ocean, atmospheric deposition impacts biogeochemical cycles. The extent to which those changes are modifying the carbon balance in oligotrophic environments such as the Mediterranean Sea that receives important Saharan dust fluxes is unknown. The DUNE (DUst experiment in a low Nutrient, low chlorophyll Ecosystem) project provides the first attempt to evaluate the changes induced in the carbon budget of a large body of oligo...

  7. Provincial allocation of carbon emission reduction targets in China: An approach based on improved fuzzy cluster and Shapley value decomposition

    International Nuclear Information System (INIS)

    An approach to determine carbon emission reduction target allocation based on the particle swarm optimization (PSO) algorithm, fuzzy c-means (FCM) clustering algorithm, and Shapley decomposition (PSO–FCM–Shapley) is proposed in this study. The method decomposes total carbon emissions into an interaction result of four components (i.e., emissions from primary, secondary, and tertiary industries, and from residential areas) which composed totally by 13 macro influential factors according to the KAYA identity. Then, 30 provinces in China are clustered into four classes according to the influential factors via the PSO–FCM clustering method. The key factors that determine emission growth in the provinces representing each cluster are investigated by applying Shapley value decomposition. Finally, based on guaranteed survival emissions, the reduction burden is allocated by controlling the key factors that decelerate CO2 emission growth rate according to the present economic development level, energy endowments, living standards, and the emission intensity of each province. A case study of the allocation of CO2 intensity reduction targets in China by 2020 is then conducted via the proposed method. The per capita added value of the secondary industry is the primary factor for the increasing carbon emissions in provinces. Therefore, China should limit the growth rate of its secondary industry to mitigate emission growth. Provinces with high cardinality of emissions have to shoulder the largest reduction, whereas provinces with low emission intensity met the minimum requirements for emission in 2010. Fifteen provinces are expected to exceed the national average decrease rates from 2011 to 2020. - Highlights: • A PSO–FCM–Shapley approach for carbon emission reduction target allocation is proposed. • Provinces of China are clustered into four classes based on factors influencing carbon emissions. • Provinces with large total emissions and high emission intensity

  8. 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

  9. 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.

  10. Stable carbon isotope ratios as proxies for CO2 migration: An experimental approach with analogue fluids

    Science.gov (United States)

    Myrttinen, A.; Becker, V.; Mayer, B.; Barth, J. A.

    2012-12-01

    Stable carbon isotope ratios have proven to be highly sensitive tracers of CO2 migration in the subsurface, provided that the δ13C value of injected CO2 is distinct from that of baseline carbon in the reservoir and in shallow aquifers. This is of great importance for tracing the movement and the fate of injected CO2 in storage reservoirs where fluid and gas samples for chemical and isotope analyses can be obtained. One fundamental aspect that needs to be considered is carbon isotope fractionation between the various dissolved inorganic carbon (DIC) species and sub- or super-critical CO2. Such isotope fractionation may occur at various stages of CO2 migration including, the initial stages of injection during CO2 dissolution; during possible CO2 desiccation in pores; during CO2 migration within the reservoir or even during potential leakage into the near-surface environment. The magnitude and direction of carbon isotope fractionation (1000lnαDIC-CO2) between the DIC species and the injected CO2 depends highly on temperature and pH. At shallow depths, where temperatures are moderate and pH values are typically close to neutral, HCO3- is the dominant form of DIC. Carbon isotope fractionation between CO2 and DIC is therefore expected to reach ~ +10 ‰, resulting in a more positive δ13C value of DIC compared to that of the injected CO2. On the other hand, during injection, elevated temperatures and pH values of below 6 are usually observed. Here, H2CO3 is the dominant form of DIC and carbon isotope fractionation of close to -1 ‰ is expected. However, literature data on isotope fractionation values between H2CO3 and CO2 at temperatures above ˜ 60 °C are limited. In order to investigate the effects of pH and temperature on carbon isotope fractionation at various subsurface conditions, including elevated temperatures and pressures typical for CO2 reservoirs, laboratory experiments with analogue fluids were conducted within the framework of the CO2ISO-LABEL project

  11. Does carbonation of steel slag particles reduce their toxicity? An in vitro approach.

    Science.gov (United States)

    Ibouraadaten, Saloua; van den Brule, Sybille; Lison, Dominique

    2015-06-01

    Mineral carbonation can stabilize industrial residues and, in the steel industry, may contribute to simultaneously valorize CO2 emissions and slag. We hypothesized that, by restricting the leaching of metals of toxicological concern such as Cr and V, carbonation can suppress the toxicity of these materials. The cytotoxic activity (WST1 assay) of slag dusts collected from a stainless and a Linz-Donawitz (LD) steel plant, before and after carbonation, was examined in J774 macrophages. The release of Cr, V, Fe, Mn and Ni was measured after incubation in artificial lung fluids mimicking the extracellular and phagolysosomal milieu to which particles are confronted after inhalation. LD slag had the higher Fe, Mn and V content, and was more cytotoxic than stainless steel slag. The cytotoxic activity of LD but not of stainless dusts was reduced after carbonation. The cytotoxic activity of the dusts toward J774 macrophages necessitated a direct contact with the cells and was reduced in the presence of inhibitors of phagocytosis (cytochalasin D) or phagolysosome acidification (bafilomycin), pointing to a key role of metallic constituents released in phagolysosomes. This in vitro study supports a limited reduction of the cytotoxic activity of LD, but not of stainless, steel dusts upon carbonation. PMID:25735930

  12. Implications of elevated CO2 on pelagic carbon fluxes in an Arctic mesocosm study – an elemental mass balance approach

    Directory of Open Access Journals (Sweden)

    J. Czerny

    2013-05-01

    Full Text Available Recent studies on the impacts of ocean acidification on pelagic communities have identified changes in carbon to nutrient dynamics with related shifts in elemental stoichiometry. In principle, mesocosm experiments provide the opportunity of determining temporal dynamics of all relevant carbon and nutrient pools and, thus, calculating elemental budgets. In practice, attempts to budget mesocosm enclosures are often hampered by uncertainties in some of the measured pools and fluxes, in particular due to uncertainties in constraining air–sea gas exchange, particle sinking, and wall growth. In an Arctic mesocosm study on ocean acidification applying KOSMOS (Kiel Off-Shore Mesocosms for future Ocean Simulation, all relevant element pools and fluxes of carbon, nitrogen and phosphorus were measured, using an improved experimental design intended to narrow down the mentioned uncertainties. Water-column concentrations of particulate and dissolved organic and inorganic matter were determined daily. New approaches for quantitative estimates of material sinking to the bottom of the mesocosms and gas exchange in 48 h temporal resolution as well as estimates of wall growth were developed to close the gaps in element budgets. However, losses elements from the budgets into a sum of insufficiently determined pools were detected, and are principally unavoidable in mesocosm investigation. The comparison of variability patterns of all single measured datasets revealed analytic precision to be the main issue in determination of budgets. Uncertainties in dissolved organic carbon (DOC, nitrogen (DON and particulate organic phosphorus (POP were much higher than the summed error in determination of the same elements in all other pools. With estimates provided for all other major elemental pools, mass balance calculations could be used to infer the temporal development of DOC, DON and POP pools. Future elevated pCO2 was found to enhance net autotrophic community carbon

  13. 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

  14. A modelling approach to estimate carbon emissions from D.R.C. deforestation

    Science.gov (United States)

    Najdovski, Nicolas; Poulter, Benjamin; Defourny, Pierre; Moreau, Inès; Maignan, Fabienne; Ciais, Philippe; Verhegghen, Astrid; Kibambe Lubamba, Jean-Paul; Jungers, Quentin; De Weirdt, Marjolein; Verbeeck, Hans; MacBean, Natasha; Peylin, Philippe

    2014-05-01

    With its 1.8 million squared kilometres, the Congo basin dense forest represents the second largest contiguous forest of the world. These extensive forest ecosystems play a significant role in the regulation of global climate by their potential carbon dioxide emissions and carbon storage. Under a stable climate, the vegetation, assumed to be at the equilibrium, is known to present neutral emissions over a year with seasonal variations. However, modifications in temperatures, precipitations, CO2 atmospheric concentrations have the potential to modify this balance leading to higher or lower biomass storage. In addition, deforestation and forest degradation have played a significant role over the past several decades and are expected to become increasingly important in the future. Here, we quantify the relative effects of deforestation and 21st century climate change on carbon emissions in Congo Basin over the next three decades (2005-2035). Carbon dioxide emissions are estimated using a series of moderate resolution (10 km) vegetation maps merged with spatially explicit deforestation projections and developed to work with a prognostic carbon cycle model. The inversion of the deforestation model allowed hindcast land-use patterns back to 1800 by using land cover change rates based on the HYDE database. Simulations were made over the Democratic Republic of Congo (DRC) using the ORCHIDEE dynamic global vegetation model with climate forcing from the CMIP5 Representative Concentration Pathway 8.5 scenario for the HadGEM2. Two simulations were made, a reference simulation with land cover fixed at 2005 and a land cover change simulation with changing climate and CO2, to quantify the net land cover change emissions and climate emissions directly. Because of the relatively high resolution of the model simulations, the spatial patterns of human-driven carbon losses can be tracked in the context of climate change, providing information for mitigation and vulnerability

  15. Exploring the options for carbon dioxide mitigation in Turkish electric power industry: System dynamics approach

    International Nuclear Information System (INIS)

    Electric power industry has a huge carbon mitigation potential, fundamentally because there are large carbon-free, renewable resource options. In Turkey, with growing demand in electricity consumption and incentives offered for natural gas fired electricity generation, CO2 emissions sourced from electric power industry had tripled over the last two decades. Current governmental strategy focuses on energy security and resource diversity in a growing economy and does not articulate sufficient mitigation targets and appropriate regulations. In this research, an original dynamic simulation model is built, validated and analyzed to explore the options for carbon mitigation in Turkish electric power industry. Model structure represents the investment, dispatch and pricing heuristics as well as the natural resource base of electricity generation in Turkey. It operates on annual basis over 30 years to simulate installed capacities and generations of power plants with alternative resources and their resulting CO2 emissions. The analysis presented in this paper reveals that there are mitigation options below 50% of business as usual growth, with common policy options such as feed-in-tariffs, investment subsidies and carbon taxes. The model can serve as an experimental platform for further analysis of problems related to carbon mitigation in Turkish electricity sector. - Highlights: • An original computer model is created to investigate carbon mitigation. • It is holistic and comprises investment, generation, dispatch, and resources. • The model's structure, information base and foresights are specific to Turkey. • Direct and indirect strategies are explored and integrated. • Dramatic reductions are possible only with supply side strategies

  16. 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

    Dissolved inorganic carbon (DIC) fluxes across the vadose zone are influenced by a complex interplay of biological, chemical and physical factors. A novel soil mesocosm system was evaluated as a tool for providing information on the mechanisms behind DIC percolation to the groundwater from...... 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...

  17. Distributional impacts of carbon pricing: A general equilibrium approach with micro-data for households

    International Nuclear Information System (INIS)

    Many policies to limit greenhouse gas emissions have at their core efforts to put a price on carbon emissions. Carbon pricing impacts households both by raising the cost of carbon intensive products and by changing factor prices. A complete analysis requires taking both effects into account. The impact of carbon pricing is determined by heterogeneity in household spending patterns across income groups as well as heterogeneity in factor income patterns across income groups. It is also affected by precise formulation of the policy (how is the revenue from carbon pricing distributed) as well as the treatment of other government policies (e.g. the treatment of transfer payments). What is often neglected in analyses of policy is the heterogeneity of impacts across households even within income or regional groups. In this paper, we incorporate 15,588 households from the U.S. Consumer and Expenditure Survey data as individual agents in a comparative-static general equilibrium framework. These households are represented within the MIT USREP model, a detailed general equilibrium model of the U.S. economy. In particular, we categorize households by full household income (factor income as well as transfer income) and apply various measures of lifetime income to distinguish households that are temporarily low-income (e.g., retired households drawing down their financial assets) from permanently low-income households. We also provide detailed within-group distributional measures of burden impacts from various policy scenarios. - Highlights: → We develop a simulation model with 15,588 households to study the distributional impacts of carbon pricing in the US. → Sources side impacts have typically been ignored in the literature biasing studies towards finding carbon pricing to be regressive. → Our general equilibrium framework allows us to capture uses and sources side impacts from carbon pricing. → We find that variation in impacts within broad socioeconomic groups may

  18. 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

  19. New approach to carbon monoxide poisoning treatment by laser-induced photodissociation of carboxyhemoglobin of cutaneous blood vessels

    Science.gov (United States)

    Asimov, Mustafo M.; Asimov, Rustam M.; Gisbrecht, Alexander

    2005-04-01

    A new approach to carbon monoxide poisoning treatment based on laser-induced photodissociation of the carboxyhemoglobin is proposed. Using the simple model of laser tissue interaction the action spectra of laser radiation on carboxyhemoglobin of cutaneous blood vessels has been calculated. The results of the calculatoins indicate that there is a relatively narrow spectral range in the visible region where one could effectively irradiate carboxyhemoglobin through the tissue not in a deep distances. In the case of deeper penetration, the action spectra of laser radiation shifts toward the longer wavelength region. Despite the similarity of the carboxyhemoglobin and oxyhemoglobin action spectra, the significant difference in quantum yields of photodissociation makes possible to develop an effective method of carbon monoxide poisoning treatment.

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

    International Nuclear Information System (INIS)

    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

  1. 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

  2. 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.

  3. Economic approach to assess the forest carbon implications of biomass energy.

    Science.gov (United States)

    Daigneault, Adam; Sohngen, Brent; Sedjo, Roger

    2012-06-01

    There is widespread concern that biomass energy policy that promotes forests as a supply source will cause net carbon emissions. Most of the analyses that have been done to date, however, are biological, ignoring the effects of market adaptations through substitution, net imports, and timber investments. This paper uses a dynamic model of forest and land use management to estimate the impact of United States energy policies that emphasize the utilization of forest biomass on global timber production and carbon stocks over the next 50 years. We show that when market factors are included in the analysis, expanded demand for biomass energy increases timber prices and harvests, but reduces net global carbon emissions because higher wood prices lead to new investments in forest stocks. Estimates are sensitive to assumptions about whether harvest residues and new forestland can be used for biomass energy and the demand for biomass. Restricting biomass energy to being sourced only from roundwood on existing forestland can transform the policy from a net sink to a net source of emissions. These results illustrate the importance of capturing market adjustments and a large geographic scope when measuring the carbon implications of biomass energy policies. PMID:22515911

  4. 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...

  5. 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.

  6. Covalent sidewall functionalization of single-walled carbon nanotubes: a photoreduction approach.

    Science.gov (United States)

    Wei, Liangming; Zhang, Yafei

    2007-12-12

    Covalent sidewall functionalization of single-walled carbon nanotubes (SWNTs) via photoreduction of aromatic ketones by alcohols is reported for the first time. Irradiation of benzophenone, benzhydrol and SWNTs in benzene resulted in covalent attachment of benzhydrol to the sidewalls of the SWNTs. A variety of tools were used to characterize the functionalized SWNTs. Raman scattering, UV-visible and near-IR spectroscopy confirm the covalent nature of the sidewall functionalization. Attenuated total reflection (ATR) FTIR and NMR provided evidence for attachment of benzhydrol onto the sidewalls of nanotubes. Thermogravimetric analysis (TGA) showed that the degree of functionalization was about one benzhydrol in 52 sidewall carbons. A long-chain hydrocarbon marker (n-C(18)H(35)) was also grafted onto the functional groups by esterification reaction for high-resolution TEM (HRTEM) visualization. PMID:20442484

  7. Covalent sidewall functionalization of single-walled carbon nanotubes: a photoreduction approach

    International Nuclear Information System (INIS)

    Covalent sidewall functionalization of single-walled carbon nanotubes (SWNTs) via photoreduction of aromatic ketones by alcohols is reported for the first time. Irradiation of benzophenone, benzhydrol and SWNTs in benzene resulted in covalent attachment of benzhydrol to the sidewalls of the SWNTs. A variety of tools were used to characterize the functionalized SWNTs. Raman scattering, UV-visible and near-IR spectroscopy confirm the covalent nature of the sidewall functionalization. Attenuated total reflection (ATR) FTIR and NMR provided evidence for attachment of benzhydrol onto the sidewalls of nanotubes. Thermogravimetric analysis (TGA) showed that the degree of functionalization was about one benzhydrol in 52 sidewall carbons. A long-chain hydrocarbon marker (n-C18H35) was also grafted onto the functional groups by esterification reaction for high-resolution TEM (HRTEM) visualization

  8. A percolation theory approach to the implantation induced diamond to amorphous-carbon transition

    International Nuclear Information System (INIS)

    The physical fact that diamond is electrically insulating while amorphous carbon and graphite are conducting is used in the present work to study the local damage that each implanted ion creates around its track and to conclude about the processes through which implanted diamond turns amorphous. Experimental data for the conductivity of Sb implanted diamond for various geometries, energies and doses are analyzed by the use of percolation theory. It seems that the amorphization of implanted diamond proceeds gradually with no well defined amorphous regions formed around the ion track. Amorphization in implanted diamond seems to occur in a way different than is believed to be the case for implanted silicon, where some direct amorphization around an ion track is suggested. This major difference can be attributed to the abnormally large change in densities between diamond and amorphous carbon or graphite which suppresses the growth of local amorphous regions in diamond. (author)

  9. 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...

  10. 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...

  11. Conductivity and Thermopower in Ropes of Carbon Nanotubes - a Tight Binding Model Approach

    International Nuclear Information System (INIS)

    We analyze the doping dependence of the thermopower and conductivity of ropes of single wall carbon nanotubes using a tight binding model. A sizeable value of the Seebeck coefficient in these systems together with its Fermi liquid like temperature behavior indicate an asymmetry near the Fermi surface. We discuss two possible explanations for this asymmetry of the electronic structure of the nanotube ropes, one due to defect states, another resulting from the intertube interactions. (author)

  12. 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...

  13. 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...

  14. 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...

  15. Carbon sequestration in Spanish Mediterranean forest under two management alternatives: A modeling approach

    OpenAIRE

    Bravo Oviedo, Felipe; Bravo Oviedo, Andrés; Díaz Balteiro, Luis

    2008-01-01

    Management implications associated with two different silvicultural strategies in two Spanish pine forests (Scots pine stands in northern Spain and Mediterranean Maritime pine stands in Central Spain) were explored. Whole-stand yield, growth models and individual tree equations were used to estimate carbon stock in forests under different silvicultural alternatives and site indexes. Each alternative was evaluated on the basis of the land expectation value (LEV). Results reveal the appropriate...

  16. 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.

  17. 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

    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...

  18. 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

  19. 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

  20. CO2 Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. Annual report, January 1, 1995--December 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Wehner, S.C.; Boomer, R.J.; Cole, R.; Preiditus, J.; Vogt, J.

    1996-09-01

    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/San Andres formation; a light oil, shallow shelf carbonate reservoir within the Permian Basin. This cost-shared effort is intended to demonstrate the viability of this underutilized technology in a specific class of domestic reservoir. 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.

  1. 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.

  2. 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.

  3. Biocompatibility of Carbon Nanotubes in Mammalian Cells: An Imaging Based Approach

    Science.gov (United States)

    Chen, Howard; Lucas, Jessica; Ponek, Hannah; Evans, Christopher; Baer, Bradly; Choung, Sara; Chen, Michelle

    2012-02-01

    Carbon nanotubes have been widely researched for ultrasensitive biomolecule detection and drug delivery. However, its impact on cells is yet to be fully characterized, mainly due to the complex biological in vivo environment. We report here a mammalian cell-imaging paradigm to study the cellular response to single-walled carbon nanotubes (SWNTs) at the single-cell level. Chinese Hamster Ovarian cells were exposed to SWNTs resuspended in phosphate buffered saline (PBS) at various concentrations. Upon exposure, we optically imaged the cells (1) to visually quantify the SWNTs' crossing of the cell membrane in real-time; (2) to both qualitatively and quantitatively assess the morphological changes associated with cellular stress in the presence of SWNTs; and (3) to serially quantify cell survival with highly sensitive bioluminescence-based imaging. Consistent with literature reports, high concentration of SWNTs acutely compromised cell division and decreased cell survival. Low concentrations were well tolerated by the cells initially but had similar effects after prolonged exposure. We discuss the inter-relationships among the cell morphology, viability, and intracellular SWNT uptake parameters, as a function of nanotube concentration and exposure time.

  4. Electronic transport in large systems through a QUAMBO-NEGF approach: Application to atomic carbon chains

    International Nuclear Information System (INIS)

    The conductance of single-atom carbon chain (SACC) between two zigzag graphene nanoribbons (GNR) is studied by an efficient scheme utilizing tight-binding (TB) parameters generated via quasi-atomic minimal basis set orbitals (QUAMBOs) and non-equilibrium Green's function (NEGF). Large systems (SACC contains more than 50 atoms) are investigated and the electronic transport properties are found to correlate with SACC's parity. The SACCs provide a stable off or on state in broad energy region (0.1-1 eV) around Fermi energy. The off state is not sensitive to the length of SACC while the corresponding energy region decreases with the increase of the width of GNR. -- Highlights: → Graphene has many superior electronic properties. → First-principles calculation are accurate but limited to system size. → QUAMBOs construct tight-binding parameters with spatial localization, and then use divide-and-conquer method. → SACC (single carbon atom chain): structure and transport show even-odd parity, and long chains are studied.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. Estimation of carbon baselines for power generation in India: the supply side approach

    International Nuclear Information System (INIS)

    In this paper, attempt has been made to develop framework for estimating realistic baseline for carbon emissions from power generation in India till the end of the Eleventh Five Year Plan Period (2010-2011). This is done through development of a realistic generation plan till 2010-2011, taking into account new Greenfield projects, capacity augmentation/addition plans and commissioning schedule of new projects and incorporating the impacts of government imposed norms for energy conservation in baseline estimate. Such a supply side framework for estimation of baselines is useful for developing countries like India where the electricity markets are supply constrained. Also, the paper demonstrates the evaluation of additional emission reductions over and above the business as usual baseline by identification and quantification of future possibilities of changes in specific coal consumption and auxiliary consumption of around 70 existing thermal power plants using data envelopment analysis (DEA)

  11. 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.

  12. 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.

  13. Assessing the Impact of Landscape Evolution on Carbon Dynamics: A Coupled Physically-Based Modelling Approach

    Science.gov (United States)

    Dialynas, Y. G.; Bastola, S.; Billings, S. A.; Bras, R. L.

    2014-12-01

    Soil erosion and deposition play an important role in the global carbon (C) cycle, constituting an important driver of atmospheric CO2. Clarification of the net effect of landscape evolution on the C cycle may be achieved using coupled fully-distributed modelling of hydro-geomorphic and biogeochemical processes. We developed a distributed model of soil organic C (SOC) dynamics within an existing coupled physically-based hydro-geomorphic model (tRIBS - Erosion) to simulate the effects of soil erosion and deposition on C dynamics at basin scale. The SOC mass balance is analytically formulated at each cell using temporally variant, continuous vertical profiles of SOC content and SOC production and oxidation rate constants derived from SOC turnover characteristics. Landscape evolution feedbacks on C dynamics include the redistribution of eroded SOC, and the alteration of the SOC production and oxidation throughout the corresponding vertical profiles due to geomorphic perturbations. At each time step, model outputs include lateral and vertical C fluxes, and SOC content, at each soil column. We applied the model to the Calhoun Experimental Forest in South Carolina, which constitutes a forest recovering from agricultural land degradation prior to the mid-20th century. To test performance we carried out a point comparison against a spreadsheet-based model, SOrCERO (Soil Organic Carbon, Erosion, Replacement, and Oxidation) of SOC dynamics, which estimates effects of SOC erosion and altered SOC production and oxidation on CO2 release at an eroding profile. At a point, time integrated results from the two models were comparable. The proposed model has the additional advantage of being able to quantify C sinks and sources across the landscape in a spatially explicit manner, by systematically accounting for topographic controls on C dynamics. Sensitivity analysis suggested that the alteration of SOC production and oxidation due to landscape evolution and management practices

  14. Total organic carbon, an important tool in a holistic approach to hydrocarbon source fingerprinting

    International Nuclear Information System (INIS)

    Total organic carbon (TOC) was used to verify the consistency of source allocation results for the natural petrogenic hydrocarbon background of the northern Gulf of Alaska and Prince William Sound where the Exxon Valdez oil spill occurred in 1998. The samples used in the study were either pre-spill sediments or from the seafloor outside the spill path. It is assumed that the natural petrogenic hydrocarbon background in the area comes from either seep oil residues and shale erosion including erosion from petroleum source rock shales, or from coals including those of the Bering River coalfields. The objective of this study was to use the TOC calculations to discriminate between the two very different sources. TOC can constrain the contributions of specific sources and rule out incorrect source allocations, particularly when inputs are dominated by fossil organic carbon. The benthic sediments used in this study showed excellent agreement between measured TOC and calculated TOC from hydrocarbon fingerprint matches of polycyclic aromatic hydrocarbons (PAH) and chemical biomarkers. TOC and fingerprint matches confirmed that TOC sources were properly identified. The matches quantify the hydrocarbon contributions of different sources to the benthic sediments and the degree of hydrocarbon winnowing by waves and currents. It was concluded that the natural petrogenic hydrocarbon background in the sediments in the area comes from eroding Tertiary shales and oil seeps along the northern Gulf of Alaska coast. Thermally mature area coals are excluded from being important contributors to the background at Prince William Sound because of their high TOC content. 26 refs., 4 figs

  15. 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.

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

    International Nuclear Information System (INIS)

    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.

  17. 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

  18. 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

  19. 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....

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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)

  5. A new baseline of organic carbon stock in European agricultural soils using a modelling approach.

    Science.gov (United States)

    Lugato, Emanuele; Panagos, Panos; Bampa, Francesca; Jones, Arwyn; Montanarella, Luca

    2014-01-01

    Proposed European policy in the agricultural sector will place higher emphasis on soil organic carbon (SOC), both as an indicator of soil quality and as a means to offset CO2 emissions through soil carbon (C) sequestration. Despite detailed national SOC data sets in several European Union (EU) Member States, a consistent C stock estimation at EU scale remains problematic. Data are often not directly comparable, different methods have been used to obtain values (e.g. sampling, laboratory analysis) and access may be restricted. Therefore, any evolution of EU policies on C accounting and sequestration may be constrained by a lack of an accurate SOC estimation and the availability of tools to carry out scenario analysis, especially for agricultural soils. In this context, a comprehensive model platform was established at a pan-European scale (EU + Serbia, Bosnia and Herzegovina, Croatia, Montenegro, Albania, Former Yugoslav Republic of Macedonia and Norway) using the agro-ecosystem SOC model CENTURY. Almost 164 000 combinations of soil-climate-land use were computed, including the main arable crops, orchards and pasture. The model was implemented with the main management practices (e.g. irrigation, mineral and organic fertilization, tillage) derived from official statistics. The model results were tested against inventories from the European Environment and Observation Network (EIONET) and approximately 20 000 soil samples from the 2009 LUCAS survey, a monitoring project aiming at producing the first coherent, comprehensive and harmonized top-soil data set of the EU based on harmonized sampling and analytical methods. The CENTURY model estimation of the current 0-30 cm SOC stock of agricultural soils was 17.63 Gt; the model uncertainty estimation was below 36% in half of the NUTS2 regions considered. The model predicted an overall increase of this pool according to different climate-emission scenarios up to 2100, with C loss in the south and east of the area

  6. Geophysical numerical modeling approach for characterizing and monitoring potential carbon sequestration injection sites

    Science.gov (United States)

    Shalek, Kyle James

    Geological sequestration has been proposed as a viable option for mitigating the vast amount of CO2 being released into the atmosphere daily. Test sites for CO2 injection have been appearing across the world to ascertain the feasibility of capturing and sequestering carbon dioxide. A major concern with full scale implementation is monitoring and verifying the permanence of injected CO2. Geophysical methods, an exploration industry standard, are non-invasive imaging techniques that can be implemented to address that concern. Geophysical methods, seismic and electromagnetic, play a crucial role in monitoring the subsurface pre- and post-injection. Seismic techniques have been the most popular but electromagnetic methods are gaining interest. The primary goal of this project was to develop a new geophysical tool, a software program called GphyzCO2, to investigate the implementation of geophysical monitoring for detecting injected CO2 at test sites. The GphyzCO2 software consists of interconnected programs that encompass well logging, seismic, and electromagnetic methods. The software enables users to design and execute 3D surface-to-surface (conventional surface seismic) and borehole-to-borehole (cross-hole seismic and electromagnetic methods) numerical modeling surveys. The generalized flow of the program begins with building a complex 3D subsurface geological model, assigning properties to the models that mimic a potential CO2 injection site, numerically forward model a geophysical survey, and analyze the results. A test site located in Warren County, Ohio was selected as the test site for the full implementation of GphyzCO2. Specific interest was placed on a potential reservoir target, the Mount Simon Sandstone, and cap rock, the Eau Claire Formation. Analysis of the test site included well log data, physical property measurements (porosity), core sample resistivity measurements, calculating electrical permittivity values, seismic data collection, and seismic

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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.

  12. 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

  13. Decomposing the changes of energy-related carbon emissions in China: Evidence from the PDA approach

    OpenAIRE

    Yue-Jun Zhang; Ya-Bin Da

    2013-01-01

    In order to investigate the main drivers of CO2 emissions changes in China during the 11th Five-Year Plan period (2006-2010) and seek the main ways to reduce CO2 emissions, we decompose the changes of energy-related CO2 emissions using the production-theoretical decomposition analysis (PDA) approach. The results indicate that, first, economic growth and energy consumption are the two main drivers of CO2 emissions increase during the sample period; particularly in the northern coastal, northwe...

  14. 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)

  15. 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.

  16. Modeling of the carbon dioxide capture process system using machine intelligence approaches

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Q.; Wu, Y.X.; Chan, C.W.; Tontiwachwuthikul, P. [University of Regina, Regina, SK (Canada)

    2011-06-15

    The objective of this paper is to study the relationships among the significant parameters impacting CO{sub 2} production. An enhanced understanding of the intricate relationships among the process parameters supports prediction and optimization, thereby improving efficiency of the CO{sub 2} capture process. Our modeling study used the 3-year operational data collected from the amine-based post combustion CO{sub 2} capture process system at the International Test Centre (ITC) of CO{sub 2} Capture located in Regina, Saskatchewan of Canada. This paper describes the data modeling process using the approaches of (1) neural network modeling combined with sensitivity analysis and (2) neuro-fuzzy modeling technique. The results from the two modeling processes were compared from the perspectives of predictive accuracy, inclusion of parameters, and support for explication of problem space. We conclude from the study that the neuro-fuzzy modeling technique was able to achieve higher accuracy in predicting the CO{sub 2} production rate than the combined approach of neural network modeling and sensitivity analysis.

  17. 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 %.

  18. 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.

  19. 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.)

  20. Carbon management strategies for US electricity generation capacity: a vintage-based approach

    International Nuclear Information System (INIS)

    Utilities are under increasing pressure to reduce power plant CO2 emissions. If the US and the world follow through on their long-term commitment to dramatically reduce emissions, this pressure will become significant over the coming decades. It is in the face of these concerns that the future of US fossil-fired power plants is examined. There are over 1337 operational fossil-fired power generating units of at least 100 MW in capacity that began operating between the early 1940s and today in the continental US. Together these units provide some 453 GW of electric power. Rapidly retiring this still valuable capital stock or undertaking large-scale immediate redevelopment with advanced power cycles as a means of addressing their greenhouse gas emissions will not be a sensible option for all of these units. Considering a conservative 40-year operating life, there are over 667 existing fossil-fired power plants, representing a capacity of over 291 GW, that have at least a decade's worth of productive life remaining. Applying Battelle's specialized analysis tools, relationships between these 667 plants and their technology type, location, emissions, and vintage have been explored. Based on these factors and the proximity of these plants to geologic reservoirs with potential for sequestering large volumes of CO2, the average costs for retrofitting these newer-vintage plants with capture technology and sequestering their CO2 into such reservoirs are presented. A discussion of a set of planned US fossil-fired power projects within the context of a carbon-constrained world is also included. (author)

  1. 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.

  2. 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; Leifeld, Jens; van Wesemaels, Bas; Schumacher, Jens; Gensior, Andreas

    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 in...... the temperate zone, carbon response functions (CRFs) were derived to model the temporal dynamic of SOC after five different LUC types (mean soil depth of 30±6 cm). Grassland establishment caused a long lasting carbon sink with a relative stock change of 128±23% and afforestation on former cropland a...... sink of 116±54%, 100 years after LUC (mean±95% confidence interval). No new equilibrium was reached within 120 years. In contrast, there was no SOC sink following afforestation of grasslands and 75% of all observations showed SOC losses, even after 100 years. Only in the forest floor, there was carbon...

  3. 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

  4. PRIORITY. Improved oil recovery and productivity from Lower Cretaceous Carbonates. 1.4.c: Compaction of Lower Cretaceous Carbonates

    Energy Technology Data Exchange (ETDEWEB)

    Foged Christensen, H.; Roedbro, L. [GEO (Denmark); Krogsboell, A. [BYG-DTU (Denmark)

    2002-09-01

    The in-situ stress state in the Valdemar field is unknown, especially with respect to the horizontal stress state. The horizontal stress state (or confining stress) is known to affect the compressibility and compaction properties of a material. The objective of this study is to evaluate the effect of different stress ratios and different loading rates on the compaction properties. Finally, the effect of water flooding (water weakening) on strength and deformation properties is studied. Two triaxial compaction tests, three constant rate of strain (CRS) oedometer tests and two waterflooding tests have been carried out on medium to high porosity non-fractured oil-saturated Valdemar Lower Cretaceous carbonate, representing the Lower Cretaceous Upper Tuxen 1 and Middle Tuxen 1 formations. The deformation properties for the elastic and plastic stress regime have been expressed in terms of the oedometric modulus, K, and a number of reloading moduli, K{sub rel}, for the corresponding fixed horizontal to vertical stress ratios. The compaction tests showed that the reloading moduli increase with increasing confining pressure. The de Waal creep parameters (bc{sub m0}, product of the de Waal dynamic friction parameter and the uniaxial compressibility) is derived from curve fitting of strain/time curves, in order to correlate laboratory to field pore collapse stress. The waterflooding tests indicated a reduction of the pore collapse stress in the order of 1000-1500 psi, comparable to the water weakening effect observed on Upper Cretaceous chalk. Further, a time delay with respect to responding to waterflooding of the material is observed. (au)

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. Evolution of porosity in the saltwater freshwater mixing zone of coastal carbonate aquifers: An alternative modelling approach

    Science.gov (United States)

    Romanov, Douchko; Dreybrodt, Wolfgang

    2006-10-01

    SummaryDissolution of calcium carbonate in the saltwater-freshwater mixing zone in carbonate islands and coastal aquifers up to now has been treated by coupling geochemical equilibrium programmes to a reactive-transport model. The result is a complex nonlinearly coupled set of differential transport-advection equations, which need high computational efforts. If dissolution rates of calcite are sufficiently fast, such that one can assume the solution to be in equilibrium with respect to calcite a highly simplified modelling approach can be used. By use of the concept of Phillips in his book: Flow and Reactions in Permeable Rock, Cambridge University Press, New York (1991) and its more general formulation by De Simoni et al. [De Simoni, M., Carrera, J., Sánchez-Vila, X., Guadagnini, A., 2005. A procedure for the solution of multicomponent reactive transport problems, Water Resource Research, 41, W11410.], it is possible to decouple the complex set of equations. To calculate initial changes of porosity in the rock matrix one needs solely to solve the advection-transport equation for salinity s. Current codes on density driven flow such as SEAWAT can be used. To obtain the dissolution capacity of the mixed saltwater-freshwater solution the calcium equilibrium concentration ceq( s) is obtained as a function of salinity by PHREEQC-2. Initial porosity changes can then be calculated by a simple analytical expression of the gradient of the spatial distribution s( x, y) of salinity, the distribution of flow fluxes q( x, y) and the second derivative of the calcium equilibrium concentration ceq( s) with respect to salinity s. This approach does no longer require large dispersivities on the order of meters; but reasonable results are obtained with dispersivity on the scale of the pore size of the porous rock, which correctly describes mixing on the molecular scale. The method is applied to a simple 1-D-domain without convective flow and a constant gradient of salinity as

  10. 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.

  11. 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

  12. 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

  13. Microbial Priming and Protected Carbon Responses to Elevated CO2 at Local to Global Scales: a New Modeling Approach

    Science.gov (United States)

    Sulman, B. N.; Oishi, C.; Shevliakova, E.; Pacala, S. W.

    2013-12-01

    The soil carbon formulations commonly used in global carbon cycle models and Earth System models (ESMs) are based on first-order decomposition equations, where turnover of carbon is determined only by the size of the carbon pool and empirical functions of responses to temperature and moisture. These models do not include microbial dynamics or protection of carbon in microaggregates and mineral complexes, making them incapable of simulating important soil processes like priming and the influence of soil physical structure on carbon turnover. We present a new soil carbon dynamics model - Carbon, Organisms, Respiration, and Protection in the Soil Environment (CORPSE) - that explicitly represents microbial biomass and protected carbon pools. The model includes multiple types of carbon with different chemically determined turnover rates that interact with a single dynamic microbial biomass pool, allowing the model to simulate priming effects. The model also includes the formation and turnover of protected carbon that is inaccessible to microbial decomposers. The rate of protected carbon formation increases with microbial biomass. CORPSE has been implemented both as a stand-alone model and as a component of the NOAA Geophysical Fluid Dynamics Laboratory (GFDL) ESM. We calibrated the model against measured soil carbon stocks from the Duke FACE experiment. The model successfully simulated the seasonal pattern of heterotrophic CO2 production. We investigated the roles of priming and protection in soil carbon accumulation by running the model using measured inputs of leaf litter, fine roots, and root exudates from the ambient and elevated CO2 plots at the Duke FACE experiment. Measurements from the experiment showed that elevated CO2 caused enhanced root exudation, increasing soil carbon turnover in the rhizosphere due to priming effects. We tested the impact of increased root exudation on soil carbon accumulation by comparing model simulations of carbon accumulation under

  14. 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.

  15. 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

  16. 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

  17. 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?

  18. Speciation of High-Pressure Carbon-Saturated COH Fluids at Buffered fO2 Conditions: An Experimental Approach

    Science.gov (United States)

    Tumiati, S.; Tiraboschi, C.; Recchia, S.; Poli, S.

    2014-12-01

    The quantitative assessment of species in COH fluids is crucial in modelling mantle processes. For instance, H2O/CO2 ratio in the fluid phase influences the location of the solidus and of carbonation/decarbonation reactions in peridotitic systems . In the scientific literature, the speciation of COH fluids has been generally assumed on the basis of thermodynamic calculations using equations of state of simple H2O-non-polar gas systems (e.g., H2O-CO2-CH4). Only few authors dealt with the experimental determination of high-pressure COH fluid species at different conditions, using diverse experimental and analytical approaches (e.g., piston cylinder+capsule-piercing+gas-chromatography/mass-spectrometry; cold-seal+silica glass capsules+Raman). We performed experiments on COH fluids using a capsule-piercing device coupled with a quadrupole mass spectrometry. This type of analyzer ensures superior performances in terms of selectivity of molecules to be detected, high acquisition rates and extended linear response range. Experiments were carried out in a rocking piston cylinder apparatus at pressure of 1 GPa and temperatures from 800 to 900°C. Carbon-saturated fluids were generated through the addition of oxalic acid dihydrate and graphite. Single/double capsules and different packing materials (BN and MgO) were used to evaluate the divergence from the thermodynamic speciation model. Moreover, to assess the effect of solutes on COH fluid speciation we also performed a set of experiments adding synthetic forsterite to the charge. To determine the speciation we assembled a capsule-piercing device that allows to puncture the capsule in a gas-tight vessel at 80°C. The extraction Teflon vessel is composed of a base part, where the capsule is allocated on a steel support, and a top part where a steel drill is mounted. To release the quenched fluids from the capsule, the base part of vessel is hand-tighten to the top part, allowing the steel pointer to pierce the capsule. The

  19. Mapping organic carbon stocks in eucalyptus plantations of the central highlands of Madagascar : a multiple regression approach

    OpenAIRE

    Razakamanarivo, R. H.; Grinand, Clovis; Razafindrakoto, M. A.; Bernoux, Martial; Albrecht, Alain

    2011-01-01

    Recent concerns about global warming have resulted in more concerted studies on quantification and modeling of carbon (C) storage in different ecosystems. The aim of this study was to assess and map the carbon stocks in above (ABG), below-ground (BLG) biomass and soil organic carbon contained in the 30 centimeter top-layer (SOC) in coppices of eucalyptus plantations in the central highlands of Madagascar in an area of 1590 ha. Relationships between C stock and various biophysical (stool or sh...

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

    International Nuclear Information System (INIS)

    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.

  1. 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

  2. A participatory approach to sustainable energy strategy development in a carbon-intensive jurisdiction: The case of Nova Scotia

    International Nuclear Information System (INIS)

    The need for governments to reduce the exposure of energy consumers to future increases in fossil fuel prices places urgent pressure on policy-makers to deliver fundamental transformations in energy strategies, particularly in jurisdictions with high dependency on fossil fuel sources (). This transformation is unlikely without a high level of stakeholder engagement in the policy development process. This paper describes two policy development processes recently undertaken in Nova Scotia in which the inclusion of stakeholder views was central to the approach. The first delivered a new institutional framework for electricity energy efficiency involving the inception of an independent performance-based administrator. The second required the delivery of a strategy to significantly increase renewable energy generation in the Province. It involved recommendations for changes in institutional arrangements, financial incentives and technological options. This process was followed by new commitments to renewable energy developments, new infrastructure for the importation of hydro-electricity, and the announcement of FITs for ocean energy. In both cases, recommendations were made by an independent academic institution, and the Government responded directly to a majority of recommendations. The paper concludes with a discussion of lessons learned and the implications for future energy policy making in carbon-intensive jurisdictions. - Research highlights: → Fundamental transformations in energy policy require stakeholder engagement to be successful. → We describe two policy development processes where stakeholder views were key considerations. → The first delivered a new institutional framework for electricity energy efficiency. → The second delivered a strategy to significantly increase renewable energy generation. → In each case, the Government directly responded to the majority of recommendations.

  3. 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

  4. Mapping carbon sequestration in forests at the regional scale - a climate biomonitoring approach by example of Germany

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Winfried; Pesch, Roland [University of Vechta, Chair of Landscape Ecology, PO Box. 1553, Vechta (Germany)

    2011-12-15

    The United Nations Framework Convention on Climate Change recognizes carbon (C) fixation in forests as an important contribution for the reduction of atmospheric pollution in terms of greenhouse gases. Spatial differentiation of C sequestration in forests either at the national or at the regional scale is therefore needed for forest planning purposes. Hence, within the framework of the Forest Focus regulation, the aim of this investigation was to statistically analyse factors influencing the C fixation and to use the corresponding associations in terms of a predictive mapping approach at the regional scale by example of the German federal state North Rhine-Westphalia. The results of the methodical scheme outlined in this article should be compared with an already-published approach applied to the same data which were used in the investigation at hand. Site-specific data on C sequestration in humus, forest trees/dead wood and soil from two forest monitoring networks were intersected with available surface information on topography, soil, climate and forestal growing areas and districts. Next, the association between the C sequestration and the influence factors were examined and modelled by linear regression analyses. The resulting regression equations were applied on the surface data to predicatively map the C sequestration for the entire study area. The computations yielded an estimation of 146.7 mio t C sequestered in the forests of North Rhine-Westphalia corresponding to 168.6 t/ha. The calculated values correspond well to according specifications given by the literature. Furthermore, the results are almost identical to those of another pilot study where a different statistical methodology was applied on the same database. Nevertheless, the underlying regression models contribute only a low degree of explanation to the overall variance of the C fixation. This might mainly be due to data quality aspects and missing influence factors in the analyses. In another

  5. 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.

  6. 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

  7. 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

  8. 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 ...

  9. 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 ...

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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

  16. Net ecosystem production and organic carbon balance of U.S. East Coast estuaries: A synthesis approach

    Science.gov (United States)

    Herrmann, Maria; Najjar, Raymond G.; Kemp, W. Michael; Alexander, Richard B.; Boyer, Elizabeth W.; Cai, Wei-Jun; Griffith, Peter C.; Kroeger, Kevin D.; McCallister, S. Leigh; Smith, Richard A.

    2015-01-01

    Net ecosystem production (NEP) and the overall organic carbon budget for the estuaries along the East Coast of the United States are estimated. We focus on the open estuarine waters, excluding the fringing wetlands. We developed empirical models relating NEP to loading ratios of dissolved inorganic nitrogen to total organic carbon, and carbon burial in the sediment to estuarine water residence time and total nitrogen input across the landward boundary. Output from a data-constrained water quality model was used to estimate inputs of total nitrogen and organic carbon to the estuaries across the landward boundary, including fluvial and tidal-wetland sources. Organic carbon export from the estuaries to the continental shelf was computed by difference, assuming steady state. Uncertainties in the budget were estimated by allowing uncertainties in the supporting model relations. Collectively, U.S. East Coast estuaries are net heterotrophic, with the area-integrated NEP of -1.5 (-2.8, -1.0) Tg C yr-1 (best estimate and 95% confidence interval) and area-normalized NEP of -3.2 (-6.1, -2.3) mol C m-2 yr-1. East Coast estuaries serve as a source of organic carbon to the shelf, exporting 3.4 (2.0, 4.3) Tg C yr-1 or 7.6 (4.4, 9.5) mol C m-2 yr-1. Organic carbon inputs from fluvial and tidal-wetland sources for the region are estimated at 5.4 (4.6, 6.5) Tg C yr-1 or 12 (10, 14) mol C m-2 yr-1 and carbon burial in the open estuarine waters at 0.50 (0.33, 0.78) Tg C yr-1 or 1.1 (0.73, 1.7) mol C m-2 yr-1. Our results highlight the importance of estuarine systems in the overall coastal budget of organic carbon, suggesting that in the aggregate, U.S. East Coast estuaries assimilate (via respiration and burial) ~40% of organic carbon inputs from fluvial and tidal-wetland sources and allow ~60% to be exported to the shelf.

  17. 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

  18. 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.

  19. Tree age-related effects on seasonal dynamics of carbon reserves in Quercus petraea: an in situ experimental approach

    Science.gov (United States)

    Gilson, Angélique; Bazot, Stéphane; Barthes, Laure; Delpierre, Nicolas; Fresneau, Chantal; Audebert, Louise; Dufrêne, Eric

    2013-04-01

    Forest productivity plays an important role in wood production and forest carbon storage capacity. It is well known that forest productivity declines with tree age (Genet et al., 2009). This decline could result from a carbon assimilation decrease and/or a modification of carbon allocation (Ryan et al., 2006 ; Genet, 2009). Relationships between tree age and leaf surface (Bond-Lamberty et al., 2002 ; Louis et al., 2012), light interception (Niinemets et al., 2005) or hydraulic constraint (Bond, 2000 ; Zaehle, 2006) have been widely studied. Yet, studies of relationships between tree age and carbon storage/remobilization processes are scarce in deciduous trees. Therefore in situ experiments appear necessary to have a better understanding of the carbon functioning of deciduous forest ecosystems. Our objective was to compare the seasonal carbon dynamics of different age oak trees classes. We studied three age categories (8, 20, 100 years) of Quercus petraea in the Barbeau national forest (France) over one leafy season. Leaves, 2010 and 2011 twigs, stem, fine and coarse roots were sampled at different key phenological stages (before budburst, at budburst, maximum leaf area index, maximum leaf mass area, summer, yellowing and winter) for determination of starch concentrations. We observed only differences between classes for 2010 twigs and fine roots. After carbon reserves remobilization during budburst, starch concentrations of 2010 twigs for 8 and 20 years old trees don't increase before the end of wood growth (i.e. end of july). Starch concentrations increase occurs just after budburst for the oldest tree category. Starch concentrations in fine roots in the two oldest trees categories are stable throughout the year. On the contrary, juvenile trees present an enhanced starch concentration in autumn. Nevertheless, for oldest tree coarse roots starch concentration increase from summer to yellowing. These first results highlight that starch storage is different between

  20. 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

  1. Integration approach for developing a high-performance biointerface: Sequential formation of hydroxyapatite and calcium carbonate by an improved alternate soaking process

    International Nuclear Information System (INIS)

    Biointerfaces are crucial for regulating biofunctions. An effective method of producing new biomaterials is surface modification, in particular, the hybrid organic-inorganic approach. In this paper, we propose a method for the sequential formation of hydroxyapatite and calcium carbonate on porous polyester membranes by using an improved alternate soaking process. The resulting hybrid membranes were characterized in terms of their calcium and phosphorus ion contents; further, their structure was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and infrared spectroscopy (IR). As a typical biofunction, protein adsorption by these hybrid membranes was investigated. Sequential hydroxyapatite and calcium carbonate formation on the membranes was successfully achieved, and the total amounts of hydroxyapatite and calcium carbonate formed were precisely regulated by the preparative conditions. The SEM and XRD characterizations were verified by comparing with the IR results. The amount of adsorbed protein correlated well with not only the amount of hydroxyapatite formed but also the combined amounts of hydroxyapatite and calcium carbonate formed. The results indicate that the hybrid membranes can function as high-performance biointerfaces that are capable of loading biomolecules such as proteins

  2. 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

  3. 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.

  4. Carbon footprints of crops from organic and conventional arable crop rotations – using a life cycle assessment approach

    DEFF Research Database (Denmark)

    Knudsen, Marie Trydeman; Meyer-Aurich, A; Olesen, Jørgen E;

    2014-01-01

    incorporated in the soil in the ‘Mulching’ rotation and removed and used for biogas production in the ‘Biogas’ rotation (and residues from biogas production were simulated to be returned to the field). A method was suggested for allocating effects of fertility building crops in life cycle assessments. The......-clover) and highlights the importance of analysing the whole crop rotation and including soil carbon changes when estimating carbon footprints of organic crops especially where green manure crops are included.......Many current organic arable agriculture systems are challenged by a dependency on imported livestock manure from conventional agriculture. At the same time organic agriculture aims at being climate friendly. A life cycle assessment is used in this paper to compare the carbon footprints of different...

  5. 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.

  6. A facile approach towards increasing the nitrogen-content in nitrogen-doped carbon nanotubes via halogenated catalysts

    Science.gov (United States)

    Ombaka, L. M.; Ndungu, P. G.; Omondi, B.; McGettrick, J. D.; Davies, M. L.; Nyamori, V. O.

    2016-03-01

    Nitrogen-doped carbon nanotubes (N-CNTs) have been synthesized at 850 °C via a CVD deposition technique by use of three ferrocenyl derivative catalysts, i.e. para-CN, -CF3 and -Cl substituted-phenyl rings. The synthesized catalysts have been characterized by NMR, IR, HR-MS and XRD. The XRD analysis of the para-CF3 catalyst indicates that steric factors influence the X-ray structure of 1,1‧-ferrocenylphenyldiacrylonitriles. Acetonitrile or pyridine was used as carbon and nitrogen sources to yield mixtures of N-CNTs and carbon spheres (CS). The N-CNTs obtained from the para-CF3 catalysts, in pyridine, have the highest nitrogen-doping level, show a helical morphology and are less thermally stable compared with those synthesized by use of the para-CN and -Cl as catalyst. This suggests that fluorine heteroatoms enhance nitrogen-doping in N-CNTs and formation of helical-N-CNTs (H-N-CNTs). The para-CF3 and para-Cl catalysts in acetonitrile yielded iron-filled N-CNTs, indicating that halogens promote encapsulation of iron into the cavity of N-CNT. The use of acetonitrile, as carbon and nitrogen source, with the para-CN and -Cl as catalysts also yielded a mixture of N-CNTs and carbon nanofibres (CNFs), with less abundance of CNFs in the products obtained using para-Cl catalysts. However, para-CF3 catalyst in acetonitrile gave N-CNTs as the only shaped carbon nanomaterials.

  7. 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

  8. 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

  9. A Novel Approach to Estimation of Time-Variable Surface Sources and Sinks of Carbon Dioxide Using Empirical Orthogonal Functions and the Kalman Filter

    Science.gov (United States)

    Zhuravlev, Ruslan; Khattatov, Boris; Kiryushov, Boris; Lukyanov, Alexander; Maksyutov, Shamil

    2010-05-01

    It is well known that greenhouse gases and, in particular, greenhouse gases of anthropogenic origin, influence the Earth climate to a great extend. Accurate estimates of strengths, and spatial and time variability of the surface sources and sinks of greenhouse gases are thus of great interest to both the scientific community and the policy makers. Carbon dioxide, (CO2), is the most important greenhouse gas of anthropogenic origin that affects radiative balance of the atmosphere and, eventually, the climate. Observations of CO2 concentrations in the atmosphere demonstrated short-time variability and spatial patterns reflecting influence of time-variable regional sources and sinks. The objective of this study is to estimate absolute contributions of various geographical regions to the total carbon dioxide budget at relatively short time scales and in a computationally efficient manner. A traditional approach to this problem includes dividing the Earth's surface by a number of non-overlapping regions and estimating the sources and sinks for each one of them. One of the most well-known and successful experiments following this approach was Transcom 3 [1], which used 22 distinct regions. In subsequent work of P. Patra et al. [3], the number of the regions has been increased to 64. In both cases, monthly mean CO2 surface emissions have been successfully estimated using ground based observations of carbon dioxide concentrations. Recently, (Feng et al, 2009 [3]), 144 distinct regions have been used and the time scale of carbon dioxide variability was reduced to 8 days using satellite observations of CO2. While very successful, the abovementioned approach relies on somewhat arbitrary division of the Earth surface to discrete regions. Refining the results would necessitate increasing the number of regions, and thus computational requirements, which in some cases might prove to be impractical. We propose an approach based on representing the surface emissions of carbon

  10. A systems biology approach uncovers cellular strategies used by Methylobacterium extorquens AM1 during the switch from multi- to single-carbon growth.

    Directory of Open Access Journals (Sweden)

    Elizabeth Skovran

    Full Text Available BACKGROUND: When organisms experience environmental change, how does their metabolic network reset and adapt to the new condition? Methylobacterium extorquens is a bacterium capable of growth on both multi- and single-carbon compounds. These different modes of growth utilize dramatically different central metabolic pathways with limited pathway overlap. METHODOLOGY/PRINCIPAL FINDINGS: This study focused on the mechanisms of metabolic adaptation occurring during the transition from succinate growth (predicted to be energy-limited to methanol growth (predicted to be reducing-power-limited, analyzing changes in carbon flux, gene expression, metabolites and enzymatic activities over time. Initially, cells experienced metabolic imbalance with excretion of metabolites, changes in nucleotide levels and cessation of cell growth. Though assimilatory pathways were induced rapidly, a transient block in carbon flow to biomass synthesis occurred, and enzymatic assays suggested methylene tetrahydrofolate dehydrogenase as one control point. This "downstream priming" mechanism ensures that significant carbon flux through these pathways does not occur until they are fully induced, precluding the buildup of toxic intermediates. Most metabolites that are required for growth on both carbon sources did not change significantly, even though transcripts and enzymatic activities required for their production changed radically, underscoring the concept of metabolic setpoints. CONCLUSIONS/SIGNIFICANCE: This multi-level approach has resulted in new insights into the metabolic strategies carried out to effect this shift between two dramatically different modes of growth and identified a number of potential flux control and regulatory check points as a further step toward understanding metabolic adaptation and the cellular strategies employed to maintain metabolic setpoints.

  11. 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

  12. 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.

  13. 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...

  14. 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

  15. 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...

  16. 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.

  17. 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, January 1, 1996--December 30, 1996

    Energy Technology Data Exchange (ETDEWEB)

    Brown, L.R.; Vadie, A.A.

    1997-08-01

    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 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 microbial nutrients to the injection water. Work on the project is divided into three phases, Planning and Analysis (9 months), Implementation (45 months), and Technology Transfer (12 months). This report covers the third year of work on the project. During Phase I, two wells were drilled in an area of the field where approximately twenty feet of Carter sand were found and appeared to contain oil bypassed by the existing waterflood. Cores from one well were obtained and used in laboratory core flood experiments. The schedule and amounts of nutrients to be employed in the field were formulated on the basis of the results from laboratory core flood experiments.

  18. 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.

  19. 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

  20. A spontaneous dissolution approach to carbon coated TiO2 hollow composite spheres with enhanced visible photocatalytic performance

    International Nuclear Information System (INIS)

    TiO2/carbon hollow composite spheres with mesoporous structure were successfully prepared by using a conventional hard template method but without an on-purpose etching process to remove the core material. A possible surface-protected dissolution mechanism was proposed to account for the spontaneous dissolution of the silica core. The thickness of carbon layer could be well controlled by adjusting the concentration of glucose in the hydrothermal reaction. Moreover, the as-prepared TiO2/C hollow spheres had remarkable light absorption in the visible region. As compared with the SiO2@TiO2 solid spheres prepared without the addition of glucose, the TiO2/C hollow spheres exhibited enhanced photocatalytic efficiency for the visible-light photodegradation of Rhodamine B.

  1. 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).

  2. A Simple and Facile Approach to Aliphatic N-Substituted Functional Eight-Membered Cyclic Carbonates and Their Organocatalytic Polymerization.

    Science.gov (United States)

    Venkataraman, Shrinivas; Ng, Victor W L; Coady, Daniel J; Horn, Hans W; Jones, Gavin O; Fung, Tak Shun; Sardon, Haritz; Waymouth, Robert M; Hedrick, James L; Yang, Yi Yan

    2015-11-01

    Aliphatic N-substituted functional eight-membered cyclic carbonates were synthesized from N-substituted diethanolamines by intramolecular cyclization. On the basis of the N-substituent, three major subclasses of carbonate monomers were synthesized (N-aryl, N-alkyl and N-carbamate). Organocatalytic ring opening polymerization (ROP) of eight-membered cyclic carbonates was explored as a route to access narrowly dispersed polymers of predictable molecular weights. Polymerization kinetics was highly dependent on the substituent on the nitrogen atom and the catalyst used for the reaction. The use of triazabicyclodecene (TBD), instead of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), as the catalyst for the N-alkyl substituted monomers significantly enhanced the rate of polymerizations. Computational studies were performed to rationalize the observed trends for TBD catalyzed polymerizations. With the optimal organocatalyst all monomers could be polymerized generating well-defined polymers within a timespan of ≤2 h with relatively high monomer conversion (≥80%) and low molar-mass dispersity (Đ(M) ≤ 1.3). Both the glass transition temperatures (T(g)) and onset of degradation temperatures (T(onset)) of these polymers were found to be N-substituent dependent and were in the range of about -45 to 35 °C and 230 to 333 °C, respectively. The copolymerization of the eight membered monomers with 6-membered cyclic comonomers including commercially available l-lactide and trimethylene carbonate produced novel copolymers. The combination of inexpensive starting materials, ease of ring-closure and subsequent polymerization makes this an attractive route to functional polycarbontes. PMID:26456146

  3. 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.

  4. 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.

  5. 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 M.; Zhou, Lingxi; Ju, Weimin; Zhang, Huifang; Machida, Toshinobu; Ciais, Philippe; Peters, Wouter; Wang, Hengmao; Chen, Baozhang; Liu, Lixin; Zhang, Chunhua; Matsueda, Hidekazu; Sawa, Yousuke

    2016-02-01

    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.

  6. 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.

  7. Simple approach to carboxyl-rich materials through low-temperature heat treatment of hydrothermal carbon in air

    International Nuclear Information System (INIS)

    It was found that a large number of oxygen-containing functional groups (OFGs) could be created on the surface of hydrothermal carbon (HTC) by simply heating at lower temperature in air during the course of our preliminary experiments which focused on oxidation pre-treatment of pristine HTC for the purpose of grafting functionalization. Especially carboxyl groups on HTC would increase significantly, from 0.53 to 3.70 mmol/g after heat treatment at 300 deg. C. So, effects of heat-treatment on the OFGs on the carbon microsphere were deeply studied to confirm and explain the findings. Experiments involving different materials (HTC, activated carbon and glucose) were performed under varying conditions (heating temperature and time, in air or in Ar atmosphere). A reaction mechanism for newly generating carboxyl groups on HTC surface during heat-treatment process was supposed based on the results from the sample characterization using Boehm titrations, infrared spectra, X-ray photoelectron spectroscopy, energy dispersive spectrometry and elemental analysis. In addition, the as heat-treated product has excellent sorption capability for Pb2+ and Cd2+ ions.

  8. Simple approach to carboxyl-rich materials through low-temperature heat treatment of hydrothermal carbon in air

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zhen; Ma Lijian; Li Shuqiong; Geng Junxia; Song Qiang; Liu Jun; Wang Chunli; Wang Hang; Li Juan [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China); Qin Zhi [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Li Shoujian, E-mail: sjli000616@scu.edu.cn [College of Chemistry, Sichuan University, Key Laboratory of Radiation Physics and Technology (Sichuan University), Ministry of Education, Chengdu 610064 (China)

    2011-08-01

    It was found that a large number of oxygen-containing functional groups (OFGs) could be created on the surface of hydrothermal carbon (HTC) by simply heating at lower temperature in air during the course of our preliminary experiments which focused on oxidation pre-treatment of pristine HTC for the purpose of grafting functionalization. Especially carboxyl groups on HTC would increase significantly, from 0.53 to 3.70 mmol/g after heat treatment at 300 deg. C. So, effects of heat-treatment on the OFGs on the carbon microsphere were deeply studied to confirm and explain the findings. Experiments involving different materials (HTC, activated carbon and glucose) were performed under varying conditions (heating temperature and time, in air or in Ar atmosphere). A reaction mechanism for newly generating carboxyl groups on HTC surface during heat-treatment process was supposed based on the results from the sample characterization using Boehm titrations, infrared spectra, X-ray photoelectron spectroscopy, energy dispersive spectrometry and elemental analysis. In addition, the as heat-treated product has excellent sorption capability for Pb{sup 2+} and Cd{sup 2+} ions.

  9. Simple approach to carboxyl-rich materials through low-temperature heat treatment of hydrothermal carbon in air

    Science.gov (United States)

    Chen, Zhen; Ma, Lijian; Li, Shuqiong; Geng, Junxia; Song, Qiang; Liu, Jun; Wang, Chunli; Wang, Hang; Li, Juan; Qin, Zhi; Li, Shoujian

    2011-08-01

    It was found that a large number of oxygen-containing functional groups (OFGs) could be created on the surface of hydrothermal carbon (HTC) by simply heating at lower temperature in air during the course of our preliminary experiments which focused on oxidation pre-treatment of pristine HTC for the purpose of grafting functionalization. Especially carboxyl groups on HTC would increase significantly, from 0.53 to 3.70 mmol/g after heat treatment at 300 °C. So, effects of heat-treatment on the OFGs on the carbon microsphere were deeply studied to confirm and explain the findings. Experiments involving different materials (HTC, activated carbon and glucose) were performed under varying conditions (heating temperature and time, in air or in Ar atmosphere). A reaction mechanism for newly generating carboxyl groups on HTC surface during heat-treatment process was supposed based on the results from the sample characterization using Boehm titrations, infrared spectra, X-ray photoelectron spectroscopy, energy dispersive spectrometry and elemental analysis. In addition, the as heat-treated product has excellent sorption capability for Pb 2+ and Cd 2+ ions.

  10. 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

  11. Application of zone-folding approach to the first-principles estimation of thermodynamic properties of carbon and ZrS2 -based nanotubes.

    Science.gov (United States)

    Bandura, Andrei V; Porsev, Vitaly V; Evarestov, Robert A

    2016-03-15

    A zone-folding (ZF) approach is applied for the estimation of the phonon contributions to thermodynamic properties of carbon-and ZrS2 -based nanotubes (NTs) of hexagonal morphology with different chiralities. The results obtained are compared with those from the direct calculation of the thermodynamic properties of NTs using PBE0 hybrid exchange-correlation functional. The phonon contribution to the stability of NTs proved to be negligible for the internal energy and small for the Helmholtz free energy. It is found that the ZF approach allows us an accurate estimation of phonon contributions to internal energy, but slightly overestimates the phonon contributions to entropy. © 2015 Wiley Periodicals, Inc. PMID:26519863

  12. Comparison of modelling approaches to atmospheric carbonation of concrete in the context of deep geological intermediate-low level waste disposal

    International Nuclear Information System (INIS)

    Full text of publication follows: Simulations of atmospheric carbonation of concrete intermediate-low level waste (ILLW) cell components are conducted in order to evaluate the potential chemical degradation during the operating period (with ventilation up to 100 years). Atmospheric carbonation of concrete in unsaturated conditions is a complex process that involves intricate couplings between transport of water and CO2 in both gas and liquid phases, capillary flow during drying of the concrete and chemical reactions involving cement hydrates with CO2 dissolved in the liquid water phase. In a first approach, the drying process of concrete is simulated with liquid water-air flow and diffusion of gas components. Preliminary results were obtained in 1-dimensional geometry with a reactive-transport numerical tool (ToughReact EOS4). These simulations consider a complex mineralogical composition of cementitious and neo-formed phases, as well as porosity / permeability evolutions due to precipitation / dissolution phenomena. The results show a strong coupling between the carbonation and the drying processes affecting both the extent and the amplitude of the mineral transformations. Carbonation depths in the order of 0.6 to 1.0*10-3 m/y are predicted for cementitious components. However, these values are slightly overestimated compared to experimental data and the computing time is quite long (several months), which call for some improvements of the drying model as well as comparison with other approaches. In this context, a series of simulations have been designed to explore the influence of the coupling between CO2 gaseous/aqueous diffusion and the flow of water. Results are presented which compare the output of different numerical codes associated with different processes: reactive diffusion of CO2 gas in stationary saturation conditions (Crunch), reactive diffusion of aqueous CO2 with water flow governed by Richards' equation (ToughReact EOS9, Hytec). Additional

  13. 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

  14. 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

  15. Satellite-derived leaf-area-index and vegetation maps as input to global carbon cycle models - A hierarchical approach

    Science.gov (United States)

    Badhwar, G. D.; Macdonald, R. B.; Mehta, N. C.

    1986-01-01

    A hierarchical procedure for developing a leaf area index (LAI) map of deciduous boreal forests is studied. The collection of spectral reflectance data from the Boundary Waters Canoe area in Minnesota using helicopter-, high-altitude aircraft-, and Landsat-mounted spectral sensors is described. The relationship between LAI and biomass and the reflectance ratio is analyzed. The sensitivity of canopy reflectance in the visible and infrared to the LAI of the canopy for various boreal forest species is evaluated. The data reveal that Landsat data are useful for producing LAI maps of deciduous forest areas and the maps provide data which clarifies the function of vegetation in the global carbon cycle models.

  16. 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

  17. 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.

  18. 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

  19. SWACO{sub 2} and WACO{sub 2} efficiency improvement in carbonate cores by lowering water salinity

    Energy Technology Data Exchange (ETDEWEB)

    Aleidan, A.; Mamora, D.D. [Texas A and M Univ., College Station, TX (United States)

    2010-07-01

    A miscible carbon dioxide (CO{sub 2}) flood study was conducted using heterogenous carbonate cores and a west Texas oil sample in order to evaluate oil recovery rates under the following 4 injection modes: (1) simultaneous water and CO{sub 2} (SWACO{sub 2}), (2) water alternating CO{sub 2} (WACO{sub 2}), (3) continuous gas injection (CGI), and (4) waterflooding (WF). Various salt concentrations were tested. Results of the study showed that for injected water with a 20 wt percent salt concentration, oil recovery rates using the SWACO{sub 2} and WACO{sub 2} methods increased to 90 and 86.5 percent of the oil initially-in-place (OIIP). Oil recovery rates for SWACO{sub 2} and WACO{sub 2} increased to 98 and 92 percent of OIIP when pure water was used. Waterflooding recovery rates remained the same for both salinity levels, which indicated that the dissolved CO{sub 2} is a critical factor in oil displacement. Results of the study suggested that CO{sub 2} solubility in water increases when the salinity of the injected water is reduced. Results indicated that the microscopic oil displacement efficiency is increased when low salinity water with CO{sub 2} is used. 18 refs., 17 figs.

  20. 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

  1. 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.

  2. Removal of toxic dichlorophenol from water by sorption with chemically activated carbon of almond shells - a green approach

    International Nuclear Information System (INIS)

    Chloro phenols (CP) represents a group of organic compounds having substituted chlorines attached to phenol ring. These trace organic pollutants represent a major environmental concern, because of toxicity, non-biodegradability, carcinogenic and stubborn properties. The adsorption of 2, 4-dichlorophenol (DCP) by chemically activated carbon of almond shells (CAC-AS) has been studied in the batch setup. Operational parameters like adsorbent dose, pH, and shaking speed were investigated. Langmuir and Freundlich isotherms were employed to calculate adsorption capacity and other sorption features of CAC-AS. The maximum amount of DCP adsorbed was 24.3 mg per gram of activated carbon derived from almond shells. Optimum conditions for DCP uptake were 2.5 g adsorbent dose, pH 5 and agitation speed of 200 rpm whereas the concentration of DCP solution was 25 mg/L (50 mL). Results corroborated that almond shells pretreated chemically, can be an excellent low cost adsorbents for removal of DCP from contaminated water. (author)

  3. 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

  4. 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

  5. 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.

  6. A systematic quantitative approach to rational drug design and discovery of novel human carbonic anhydrase IX inhibitors.

    Science.gov (United States)

    Sethi, Kalyan K; Verma, Saurabh M

    2014-08-01

    Drug design involves the design of small molecules that are complementary in shape and charge to the biomolecular target with which they interact and therefore will bind to it. Three-dimensional quantitative structure-activity relationship (3D-QSAR) studies were performed for a series of carbonic anhydrase IX inhibitors using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) techniques with the help of SYBYL 7.1 software. The large set of 36 different aromatic/heterocyclic sulfamates carbonic anhydrase (CA, EC 4.2.1.1) inhibitors, such as hCA IX, was chosen for this study. The conventional ligand-based 3D-QSAR studies were performed based on the low energy conformations employing database alignment rule. The ligand-based model gave q(2) values 0.802 and 0.829 and r(2) values 1.000 and 0.994 for CoMFA and CoMSIA, respectively, and the predictive ability of the model was validated. The predicted r(2) values are 0.999 and 0.502 for CoMFA and CoMSIA, respectively. SEA (steric, electrostatic, hydrogen bond acceptor) of CoMSIA has the significant contribution for the model development. The docking of inhibitors into hCA IX active site using Glide XP (Schrödinger) software revealed the vital interactions and binding conformation of the inhibitors. The CoMFA and CoMSIA field contour maps are well in agreement with the structural characteristics of the binding pocket of hCA IX active site, which suggests that the information rendered by 3D-QSAR models and the docking interactions can provide guidelines for the development of improved hCA IX inhibitors as leads for various types of metastatic cancers including those of cervical, renal, breast and head and neck origin. PMID:24090419

  7. Transfer of low-carbon technology under the United Nations Framework Convention on Climate Change: the case of the Global Environment Facility and its market transformation approach in India

    OpenAIRE

    Haum, Rüdiger H

    2011-01-01

    The transfer of low-carbon technology to developing countries is one of the key means to reduce greenhouse gas emissions in developing countries and therefore a key aspect of the United Nations Framework Convention on Climate Change (UNFCCC). This thesis aims to contribute to the understanding of international low-carbon technology transfer and how it might do justice to the interest of developed and developing countries. The empirical example is the technology transfer approach and its imple...

  8. 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

  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, 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.

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

    International Nuclear Information System (INIS)

    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. (paper)

  11. 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.

  12. 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.

  13. 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.

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

    International Nuclear Information System (INIS)

    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

  15. 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.

  16. 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.

  17. 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

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

    International Nuclear Information System (INIS)

    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

  19. 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.

  20. Multilayer Dye Adsorption in Activated Carbons-Facile Approach to Exploit Vacant Sites and Interlayer Charge Interaction.

    Science.gov (United States)

    Hadi, Pejman; Guo, Jiaxin; Barford, John; McKay, Gordon

    2016-05-17

    Altering the textural properties of activated carbons (ACs) via physicochemical techniques to increase their specific surface area and/or to manipulate their pore size is a common practice to enhance their adsorption capacity. Instead, this study proposes the utilization of the vacant sites remaining unoccupied after dye uptake saturation by removing the steric hindrance and same-charge repulsion phenomena via multilayer adsorption. Herein, it has been shown that the adsorption capacity of the fresh AC is a direct function of the dye molecular size. As the cross-sectional area of the dye molecule increases, the steric hindrance effect exerted on the neighboring adsorbed molecules increases, and the geometrical packing efficiency is constrained. Thus, ACs saturated with larger dye molecules render higher concentrations of vacant adsorption sites which can accommodate an additional layer of dye molecules on the exhausted adsorbent through interlayer attractive forces. The second layer adsorption capacity (60-200 mg·g(-1)) has been demonstrated to have a linear relationship with the uncovered surface area of the exhausted AC, which is, in turn, inversely proportional to the adsorbate molecular size. Unlike the second layer adsorption, the third layer adsorption is a direct function of the charge density of the second layer. PMID:27088796

  1. 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.

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

    Science.gov (United States)

    Papanicolaou, A. N. (Thanos); Wacha, Kenneth M.; Abban, Benjamin K.; Wilson, Christopher G.; Hatfield, Jerry L.; Stanier, Charles O.; Filley, Timothy R.

    2015-11-01

    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 ER as constant, usually equal to unity. The goal of this study is to provide spatiotemporal predictions of SOC stocks at the hillslope scale that account for the selective entrainment and deposition of lighter size fractions. It is hypothesized herein that ER values may vary depending on hillslope location, Land Use/Land Cover (LULC) conditions, and magnitude of the hydrologic event. An ER module interlinked with two established models, CENTURY and Watershed Erosion Prediction Project, is developed that considers the effects of changing runoff coefficients, bare soil coverage, tillage depth, fertilization, and soil roughness on SOC redistribution and storage. In this study, a representative hillslope is partitioned into two control volumes (CVs): a net erosional upslope zone and a net depositional downslope zone. We first estimate ER values for both CVs I and II for different hydrologic and LULC conditions. Second, using the improved ER estimates for the two CVs, we evaluate the effects that management practices have on SOC redistribution during different crop rotations. Overall, LULC promoting less runoff generally yielded higher ER values, which ranged between 0.97 and 3.25. Eroded soils in the upland CV were up to 4% more enriched in SOC than eroded soils in the downslope CV due to larger interrill contributions, which were found to be of equal importance to rill contributions. The chronosequence in SOC storage for the erosional zone revealed that conservation tillage and enhanced crop yields begun in the 1980s reversed the downward trend in SOC losses, causing nearly 26% of the lost SOC to be regained.

  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. Partitioning in trees and soil (PiTS) - a experimental approach to improve knowledge of forest carbon dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Jeffrey [ORNL; Garten Jr, Charles T [ORNL; Iversen, Colleen M [ORNL; Norby, Richard J [ORNL; Thornton, Peter E [ORNL; Weston, David [ORNL; Gu, Lianhong [ORNL; Brice, Deanne Jane [ORNL; Childs, Joanne [ORNL; Evans, R [University of Tennessee, Knoxville (UTK)

    2012-01-01

    Summary The dynamics of rapid changes in carbon (C) partitioning within forest ecosystems are not well understood, which limits improvement of mechanistic models of C cycling. Our objective was to inform model processes by describing relationships between C partitioning and accessible environmental or physiological measurements, with a special emphasis on belowground C flux. We exposed eight 7-year-old loblolly pine trees to air enriched with 13CO2 and then implemented adjacent light shade (LS) and heavy shade (HS) treatments in order to manipulate C uptake and flux. A soil pit was dug adjacent to the trees to provide greater access belowground. The impacts of shading on photosynthesis, plant water potential, sap flow, basal area growth, root growth, and soil C exchange rate (CER) were assessed for each tree over a three-week period. The progression of the 13C label was concurrently tracked from the atmosphere through foliage, phloem, roots, and soil CO2 efflux. The HS treatment significantly reduced C uptake, sap flow, stem growth and root standing crop, and resulted in greater residual soil water content to 1 m depth. Sap flow was strongly correlated with CER on the previous day, but not the current day, with no apparent treatment effect on the relationship. The 13C label was immediately detected in foliage on label day (half-life = 0.5 d), progressed through phloem by day 2 (half-life = 4.7 d), roots by day 2-4, and subsequently was evident as respiratory release from soil which peaked between days 3-6. The 13C of soil CO2 efflux was strongly correlated with phloem 13C on the previous day, or two days earlier. These data detail the timing and relative magnitude of C flux through a young pine stand in relation to environmental conditions. Refinement of belowground sampling will be necessary to adequately separate and quantify the flux of recently fixed C into roots, and fate of that new C as respiratory, mycorrhizal or exudative release, storage or partitioning

  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. 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

  8. 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.

  9. High Resolution Chemostratigraphy of Khartam Member of the Permo-Triassic Khuff Carbonate : Outcrop Reservoir Analog Approach from Central Saudi Arabia

    Science.gov (United States)

    Abdullatif, Osman; Adam, Ammar

    2013-04-01

    The Permo- Triassic carbonate Khuff reservoir (and equivalents) in the Middle East are estimated to contain about 15-20 % of the world's gas reserves. Excellently exposed Permian-Triassic outcropping strata in central Saudi Arabia provide good outcrop analog to the subsurface Khuff reservoir. The outcrop analog can allow examining and evaluating the stratigraphical and sedimentological heterogeneity which has important impact or reservoir quality and architecture. This chemostratigraphic study is part of an integrated outcrop analog study utilizing both field and laboratory stratigraphical and sedimentological data. The study objective is to characterize the chemostratigraphic properties and signatures related to depositional facies, diagenetic overprint, cyclicity and stratigraphic hierarchy. The Chemostratigraphic outcrop analog study is intended to provide a database and to enhance understanding and prediction of the Khuff carbonate reservoir rocks heterogeneity and quality. The field work included detailed sedimentological and stratigraphical description and analysis, gamma-ray logging and bed-by-bed sampling of outcrop sections of the Khartam Member. Lithofacies varies from mudstone, wackestone, packstone to grainstone and several meter to less than meter scale cyclicity were determined. For all samples collected chemical analysis was carried out for major, trace and rare earth elements. The chemostratigraphic signatures, based on major, trace and rare earth elements, and observed at the outcrop sections is capable of capturing stratigraphic and sedimentologic features observed at the outcrop scale and related to lithofacies, cyclicity, stacking pattern and surfaces. Reservoir and non reservoir facies were also identified and correlated. The high resolution chemostratigraphic approach used in this study may help to refine of stratigraphic hierarchy and reservoir models based on subsurface data. Consequently, this might contribute to better understanding of

  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. Egg-Box Structure in Cobalt Alginate: A New Approach to Multifunctional Hierarchical Mesoporous N-Doped Carbon Nanofibers for Efficient Catalysis and Energy Storage

    OpenAIRE

    Li, Daohao; Lv, Chunxiao; Liu, Long; Xia, Yanzhi; She, Xilin; Guo, Shaojun; Yang, Dongjiang

    2015-01-01

    Carbon nanomaterials with both doped heteroatom and porous structure represent a new class of carbon nanostructures for boosting electrochemical application, particularly sustainable electrochemical energy conversion and storage applications. We herein demonstrate a unique large-scale sustainable biomass conversion strategy for the synthesis of earth-abundant multifunctional carbon nanomaterials with well-defined doped heteroatom level and multimodal pores through pyrolyzing electrospinning r...

  12. 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

  13. 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

  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. 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.

  18. 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

  19. Carbon footprint of canned mussels from a business-to-consumer approach. A starting point for mussel processors and policy makers

    International Nuclear Information System (INIS)

    The increasing demand for environmental information on the global warming impact of products requires a solid methodological framework which guarantees comparability and communicability. The publicly available specification PAS 2050 combines approaches to a variety of greenhouse gas specific assessment issues to deliver a globally applicable product Carbon Footprinting (CF) method, which is expected to be widely accepted. Specifically, this paper aims to demonstrate the implementation of a CF scheme for a common canned mussel product according to PAS 2050 guidelines. A final value of 4.35 kg CO2e per triple pack of round cans of mussels was calculated. Furthermore, this CF study led to identify primary packaging (can production) and mussel shell management as the main activities where efforts should focus for climate change mitigation. Throughout this case study, CF opportunities and drawbacks are discussed. The whole text tries to provide a starting point for both mussel processors and policy makers to benefit from the potential advantages of a responsible use of this increasingly popular tool.

  20. 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.

  1. CO2 Huff-n-Puff Process in a Light Oil Shallow Shelf Carbonate Reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Boomer, R.J.; Cole, R.; Kovar, M.; Prieditis, J.; Vogt, J.; Wehner, S.

    1999-02-24

    The application cyclic CO2, often referred to as the CO2 Huff-n-Puff process, may find its niche in the maturing waterfloods of the Permian Basin. Coupling the CO2 Huff-n-Puff process to miscible flooding applications could provide the needed revenue to sufficiently mitigate near-term negative cash flow concerns in capital-intensive miscible projects. Texaco Exploration and Production Inc. and the US Department of Energy have teamed up in a attempt to develop the CO2 Huff-n-Puff process in the Grayburg and San Andres formations which are light oil, shallow shelf carbonate reservoirs that exist 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.

  2. The economic impact of carbon pricing with regulated electricity prices in China—An application of a computable general equilibrium approach

    International Nuclear Information System (INIS)

    We use a dynamic CGE model (SICGE) to assess the economic and climate impacts of emissions trading system (ETS) in China with a carbon price of 100 Yuan/ton CO2. A particular focus is given to the regulated electricity price regime, which is a major concern of electricity sector’s cost-effective participation in ETS in China. We found: (1) Carbon pricing is an effective policy for China to reduce CO2 emissions. Total CO2 emissions reduction ranges from 6.8% to 11.2% in short-term. (2) Rigid electricity price entails lower CO2 emissions reduction but can be considered as a feasible starting point to introduce carbon pricing policies in short-term as long as governmental subsidies are given to electricity production. (3) In mid- and long-term, the efficient policy is to earmark carbon revenue with competitive electricity price. We propose to use carbon revenue to reduce consumption tax in the first year of the introduction of carbon price and to use the carbon revenue to reduce production tax in following years. - Highlights: • We use a CGE model to assess the impacts of carbon pricing in China. • We test different scenarios of carbon cost pass-through in electricity price. • Carbon pricing policy cost-efficiency is examined with double-dividend hypothesis

  3. 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

  4. 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...

  5. 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

  6. Carbon-negative biofuels

    International Nuclear Information System (INIS)

    Current Kyoto-based approaches to reducing the earth's greenhouse gas problem involve looking for ways to reduce emissions. But these are palliative at best, and at worst will allow the problem to get out of hand. It is only through sequestration of atmospheric carbon that the problem can be solved. Carbon-negative biofuels represent the first potentially huge assault on the problem, in ways that are already technically feasible and practicable. The key to carbon negativity is to see it not as technically determined but as an issue of strategic choice, whereby farmers and fuel producers can decide how much carbon to return to the soil. Biochar amendment to the soil not only sequesters carbon but also enhances the fertility and vitality of the soil. The time is approaching when biofuels will be carbon negative by definition, and, as such, they will sweep away existing debates over their contribution to the solution of global warming. (author)

  7. Carbon nanotubes decorating methods

    OpenAIRE

    A.D. Dobrzańska-Danikiewicz; D. Łukowiec; D. Cichock; W. Wolany

    2013-01-01

    Purpose: The work is to present and characterise various methods of depositing carbon nanotubes with nanoparticles of precious metals, and also to present the results of own works concerning carbon nanotubes coated with platinum nanoparticles.Design/methodology/approach: Electron transmission and scanning microscopy has been used for imaging the structure and morphology of the nanocomposites obtained and the distribution of nanoparticles on the surface of carbon nanotubes.Findings: The studie...

  8. 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

  9. 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...

  10. 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。

  11. 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...... of oil. In previous studies, compositions of injected waterfloods (IJW) have been correlated to the observed oil recovery. This study highlights differences between IJW and ITW for different studies reported in literature....

  12. Forest Carbon Storage in the Northern Midwest, USA: A Bottom-Up Scaling Approach Combining Local Meteorological and Biometric Data With Regional Forest Inventories

    Science.gov (United States)

    Curtis, P. S.; Gough, C. M.; Vogel, C. S.

    2005-12-01

    Carbon (C) storage increasingly is considered an important part of the economic return of forestlands, making easily parameterized models for assessing current and future C storage important for both ecosystem and money managers. For the deciduous forests of the northern midwest, USA, detailed information relating annual C storage to local site characteristics can be combined with spatially extensive forest inventories to produce simple, robust models of C storage useful at a variety of scales. At the University of Michigan Biological Station (45o35`' N, 84o42`' W) we measured C storage, or net ecosystem production (NEP), in 65 forest stands varying in age, disturbance history, and productivity (site index) using biometric methods, and independently measured net C exchange at the landscape level using meteorological methods. Our biometric and meteorological estimates of NEP converged to within 1% of each other over five years, providing important confirmation of the robustness of these two approaches applied within northern deciduous forests (Gough et al. 2005). We found a significant relationship between NEP, stand age ( A, yrs), and site index ( Is, m), where NEP = 0.134 + 0.022 * (LN[ A* Is]) (r2 = 0.50, P forests of similar species composition reported in the USDA Forest Inventory and Analysis database (ncrs2.fs.fed.us/4801/fiadb/) to estimate forest C storage at different scales across the upper midwest, Great Lakes region. Model estimates were validated against independent estimates of C storage for other forests in the region. At the local ecosystem-level (~1 km2) C storage averaged 1.52 Mg ha-1 yr-1. Scaling to the two-county area surrounding our meteorological and biometric study sites, average stand age decreased and site index increased, resulting in estimated storage of 1.62 Mg C ha-1 yr-1, or 0.22 Tg C yr-1 in the 1350 km2 of deciduous forest in this area. For the state of Michigan (31,537 km2 of deciduous forest), average uptake was estimated at 1

  13. 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...

  14. 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...

  15. Egg-Box Structure in Cobalt Alginate: A New Approach to Multifunctional Hierarchical Mesoporous N-Doped Carbon Nanofibers for Efficient Catalysis and Energy Storage.

    Science.gov (United States)

    Li, Daohao; Lv, Chunxiao; Liu, Long; Xia, Yanzhi; She, Xilin; Guo, Shaojun; Yang, Dongjiang

    2015-08-26

    Carbon nanomaterials with both doped heteroatom and porous structure represent a new class of carbon nanostructures for boosting electrochemical application, particularly sustainable electrochemical energy conversion and storage applications. We herein demonstrate a unique large-scale sustainable biomass conversion strategy for the synthesis of earth-abundant multifunctional carbon nanomaterials with well-defined doped heteroatom level and multimodal pores through pyrolyzing electrospinning renewable natural alginate. The key part for our chemical synthesis is that we found that the egg-box structure in cobalt alginate nanofiber can offer new opportunity to create large mesopores (∼10-40 nm) on the surface of nitrogen-doped carbon nanofibers. The as-prepared hierarchical carbon nanofibers with three-dimensional pathway for electron and ion transport are conceptually new as high-performance multifunctional electrochemical materials for boosting the performance of oxygen reduction reaction (ORR), lithium ion batteries (LIBs), and supercapacitors (SCs). In particular, they show amazingly the same ORR activity as commercial Pt/C catalyst and much better long-term stability and methanol tolerance for ORR than Pt/C via a four-electron pathway in alkaline electrolyte. They also exhibit a large reversible capacity of 625 mAh g(-1) at 1 A g(-1), good rate capability, and excellent cycling performance for LIBs, making them among the best in all the reported carbon nanomaterials. They also represent highly efficient carbon nanomaterials for SCs with excellent capacitive behavior of 197 F g(-1) at 1 A g(-1) and superior stability. The present work highlights the importance of biomass-derived multifunctional mesoporous carbon nanomaterials in enhancing electrochemical catalysis and energy storage. PMID:27162980

  16. 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.

  17. Systematic approach to determination of maximum achievable capture capacity via leaching and carbonation processes for alkaline steelmaking wastes in a rotating packed bed.

    Science.gov (United States)

    Pan, Shu-Yuan; Chiang, Pen-Chi; Chen, Yi-Hung; Chen, Chun-Da; Lin, Hsun-Yu; Chang, E-E

    2013-01-01

    Accelerated carbonation of basic oxygen furnace slag (BOFS) coupled with cold-rolling wastewater (CRW) was performed in a rotating packed bed (RPB) as a promising process for both CO2 fixation and wastewater treatment. The maximum achievable capture capacity (MACC) via leaching and carbonation processes for BOFS in an RPB was systematically determined throughout this study. The leaching behavior of various metal ions from the BOFS into the CRW was investigated by a kinetic model. In addition, quantitative X-ray diffraction (QXRD) using the Rietveld method was carried out to determine the process chemistry of carbonation of BOFS with CRW in an RPB. According to the QXRD results, the major mineral phases reacting with CO2 in BOFS were Ca(OH)2, Ca2(HSiO4)(OH), CaSiO3, and Ca2Fe1.04Al0.986O5. Meanwhile, the carbonation product was identified as calcite according to the observations of SEM, XEDS, and mappings. Furthermore, the MACC of the lab-scale RPB process was determined by balancing the carbonation conversion and energy consumption. In that case, the overall energy consumption, including grinding, pumping, stirring, and rotating processes, was estimated to be 707 kWh/t-CO2. It was thus concluded that CO2 capture by accelerated carbonation of BOFS could be effectively and efficiently performed by coutilizing with CRW in an RPB. PMID:24236803

  18. Scaling approach of terrestrial carbon cycle over Alaska's black spruce forests: a synthesis of field observation, remote sensing, and ecosystem modeling

    Science.gov (United States)

    Ueyama, M.; Date, T.; Harazono, Y.; Ichii, K.

    2007-12-01

    Spatio-temporal scale up of the eddy covariance data is an important challenge especially in the northern high latitude ecosystems, since continuous ground observations are rarely conducted. In this study, we measured the carbon fluxes at a black spruce forest in interior Alaska, and then scale up the eddy covariance data to spatio- temporal variations in regional carbon budget by using satellite remote sensing data and a process based ecosystem model, Biome-BGC. At point scale, both satellite-based empirical model and Biome-BGC could reproduce seasonal and interannual variations in GPP/RE/NEE. The magnitude of GPP/RE is also consistent among the models. However, spatial patterns in GPP/RE are something different among the models; high productivity in low elevation area is estimated by the satellite-based model whereas insignificant relationship is simulated by Biome-BGC. Long- term satellite records, AVHRR and MODIS, show the gradual decline of NDVI in Alaska's black spruce forests between 1981 and 2006, resulting in a general trend of decreasing GPP/RE for Alaska's black spruce forests. These trends are consistent with the Biome-BGC simulation. The trend of carbon budget is also consistent among the models, where the carbon budget of black spruce forests did not significantly change in the period. The simulated results suggest that the carbon fluxes in black spruce forests could be more sensitive to water availability than air temperature.

  19. 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

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Daniel J [ORNL; Turner, David P [Oregon State University, Corvallis; Stinson, Graham [Pacific Forestry Centre, Canadian Forest Service; Mcguire, David [University of Alaska; Wei, Yaxing [ORNL; West, Tristram O. [Joint Global Change Research Institute, PNNL; Heath, Linda S. [USDA Forest Service; De Jong, Bernardus [ECOSUR; McConkey, Brian G. [Agriculture and Agri-Food Canada; Birdsey, Richard A. [U.S. Department of Agriculture Forest Service; Kurz, Werner [Canadian Forest Service; Jacobson, Andrew [NOAA ESRL and CIRES; Huntzinger, Deborah [University of Michigan; Pan, Yude [U.S. Department of Agriculture Forest Service; Post, Wilfred M [ORNL; Cook, Robert B [ORNL

    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 yr1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (248 TgC yr1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (297 TgC yr1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr1), 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 tobe a small net source (+18 TgC yr1) due to land use change between 1993 and 2002. We compare these inventorybased 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 yr1 and 931 TgC yr1, 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 yr1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

  20. 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.

  1. 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.

  2. 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

    OpenAIRE

    Nasr-El-Din H. A.; Hawkins B. F.

    2006-01-01

    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 ch...

  3. 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.

  4. 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.

  5. 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

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

    International Nuclear Information System (INIS)

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

  7. A life-cycle approach to technology, infrastructure, and climate policy decision making: Transitioning to plug-in hybrid electric vehicles and low-carbon electricity

    Science.gov (United States)

    Samaras, Constantine

    In order to mitigate the most severe effects of climate change, large global reductions in the current levels of anthropogenic greenhouse gas (GHG) emissions are required in this century to stabilize atmospheric carbon dioxide (CO2) concentrations at less than double pre-industrial levels. The Intergovernmental Panel on Climate Change (IPCC) fourth assessment report states that GHG emissions should be reduced to 50-80% of 2000 levels by 2050 to increase the likelihood of stabilizing atmospheric CO2 concentrations. In order to achieve the large GHG reductions by 2050 recommended by the IPCC, a fundamental shift and evolution will be required in the energy system. Because the electric power and transportation sectors represent the largest GHG emissions sources in the United States, a unique opportunity for coupling these systems via electrified transportation could achieve synergistic environmental (GHG emissions reductions) and energy security (petroleum displacement) benefits. Plug-in hybrid electric vehicles (PHEVs), which use electricity from the grid to power a portion of travel, could play a major role in reducing greenhouse gas emissions from the transport sector. However, this thesis finds that life cycle GHG emissions from PHEVs depend on the electricity source that is used to charge the battery, so meaningful GHG emissions reductions with PHEVs are conditional on low-carbon electricity sources. Power plants and their associated GHGs are long-lived, and this work argues that decisions made regarding new electricity supplies within the next ten years will affect the potential of PHEVs to play a role in a low-carbon future in the coming decades. This thesis investigates the life cycle engineering, economic, and policy decisions involved in transitioning to PHEVs and low-carbon electricity. The government has a vast array of policy options to promote low-carbon technologies, some of which have proven to be more successful than others. This thesis uses life

  8. 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

  9. Allocation of atmospheric CO2 into labile sub-surface carbon pools: a stable isotope labelling approach in a tundra wetland

    Science.gov (United States)

    Rüggen, Norman; Knoblauch, Christian; Pfeiffer, Eva-Maria

    2015-04-01

    Greenhouse gas emissions from permafrost-affected wetlands are intensively studied due to their important role in the global carbon cycle. There are concerns of increasing methane and carbon dioxide fluxes from tundra wetlands due to permafrost degradation and hydrology changes in a warming Arctic. Understanding the sub-surface carbon pool interactions will improve the prediction on how trace gas fluxes from these ecosystems will respond to changing environmental conditions. Partitioning the sources of greenhouse gas fluxes will help to evaluate the quantitative role of recently produced plant photosynthates. Furthermore, partitioning allows separating respiration of long-term stored organic matter and freshly produced plant products. This knowledge is crucial for understanding the response of greenhouse gas fluxes in such wetlands to environmental changes. An in situ 13CO2 pulse-labelling experiment has been conducted in the northeast Siberian tundra (Samoylov island, Lena river delta) in August 2013 to quantify interactions among sub-surface carbon pools (DIC, DOC, CH4) in three depths (6, 16 and 36 cm) of the active layer. The experimental site was a low-centred polygon centre in a polygonal tundra landscape, with a sedge-moss (Carex-Scorpidium) plant association. The water table was at the soils' surface and the permafrost table in a depth of 50 cm. After the system has been 13CO2 pulse labelled, all three studied subsurface carbon pools (CH4, DIC and DOC) were clearly 13C-enriched, which accounts for atmospheric C incorporated into these pools. One day after the labelling, in 6 cm depth 1.5 percent of DIC and 0.1 percent of CH4were replaced by label C, which then steadily declined over a ten days period. The label C content of DOC increased gradually over the same period. In 16 cm depth, the label C increased gradually after labelling in both DIC and CH4. Label C was found in DIC and CH4 even in a depth of 36 cm, although in less pronounced concentrations

  10. Transgenic approaches to altering carbon and nitrogen partitioning in whole plants: assessing the potential to improve crop yields and nutritional quality

    OpenAIRE

    Yadav, Umesh P.; Ayre, Brian G.; Bush, Daniel R.

    2015-01-01

    The principal components of plant productivity and nutritional value, from the standpoint of modern agriculture, are the acquisition and partitioning of organic carbon (C) and nitrogen (N) compounds among the various organs of the plant. The flow of essential organic nutrients among the plant organ systems is mediated by its complex vascular system, and is driven by a series of transport steps including export from sites of primary assimilation, transport into and out of the phloem and xylem,...

  11. 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...

  12. 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...

  13. 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.

  14. 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

  15. 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

  16. Post waterflood CO{sub 2} miscible flood in light oil, fluvial: Dominated deltaic reservoir. First quarterly technical progress report, Fiscal year 1994, October 1, 1993--December 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    1994-01-15

    Production from the Port Neches CO{sub 2} project was initiated on December 6, 1993 after having been shut-in since the start of CO{sub 2} injection on September 22, 1993 to allow reservoir pressure to build. Rates were established at 236 barrels of oil per day (BOPD) from two wells in the 235 acre waterflood project area, which before project initiation had produced only 80 BOPD from the entire area. These wells are flowing large amounts of fluid due to the high reservoir pressure and their oil percentages are increasing as a result of the CO{sub 2} contacting the residual oil. One well, the H. J. Kuhn No. 15-R is flowing 217 BOPD, 1139 BWPD, and 2500 MCFPD of CO{sub 2} at a flowing tubing pressure (FTP) of 890 psi. The other producing well, the H. J. Kuhn No. 33, is currently flowing 19 BOPD, 614 BWPD, and 15 MCFPD at a FTP of 400 psi. Unexpectedly high rates of CO{sub 2} production are being made from Well No. 15-R and from the W. R. Stark ``B`` No. 8. This No. 8 well produced 7 BOPD, 697 BWPD, and 15 MCFPD prior to being shut-in during September to allow for the reservoir pressure to build by injecting CO{sub 2}, but when opened on December 6, the well flowed dry CO{sub 2} at a rate of 400 MCFPD for a two day test period. More sustained production tests will be obtained after all wells are tied into the new production facility. Many difficulties occurred in the drilling of the horizontal CO{sub 2} injection well but a successful completion across 2501 of sand has finally been accomplished. A formation dip of 11--14 degrees in the area where the well was being drilled made the proposed 1500{prime} horizontal sand section too difficult to accomplish. The shale section directly above the sand caused sticking problems on two separate occasions resulting in two sidetracks of the well around stuck pipe. The well will be tied into the facility and CO{sub 2} injection into the well will begin before February 1, 1994.

  17. CO{sub 2} Huff-n-Puff process in a light oil shallow shelf carbonate reservoir. 1994 Annual report

    Energy Technology Data Exchange (ETDEWEB)

    Wehner, S.C.

    1995-05-01

    It is anticipated that this project will show that the application of the CO{sub 2} Huff-n-Puff process in shallow shelf carbonates can be economically implemented to recover appreciable volumes of light oil. The goals of the project are the development of guidelines for cost-effective selection of candidate reservoirs and wells, along with estimating recovery potential. The selected site for the demonstration project is the Central Vacuum Unit waterflood in Lea County, New Mexico. Work is nearing completion on the reservoir characterization components of the project. The near-term emphasis is to, (1) provide an accurate distribution of original oil-in-place on a waterflood pattern entity level, (2) evaluate past recovery efficiencies, (3) perform parametric simulations, and (4) forecast performance for a site specific field demonstration of the proposed technology. Macro zonation now exists throughout the study area and cross-sections are available. The Oil-Water Contact has been defined. Laboratory capillary pressure data was used to define the initial water saturations within the pay horizon. The reservoir`s porosity distribution has been enhanced with the assistance of geostatistical software. Three-Dimensional kriging created the spatial distributions of porosity at interwell locations. Artificial intelligence software was utilized to relate core permeability to core porosity, which in turn was applied to the 3-D geostatistical porosity gridding. An Equation-of-State has been developed and refined for upcoming compositional simulation exercises. Options for local grid-refinement in the model are under consideration. These tasks will be completed by mid-1995, prior to initiating the field demonstrations in the second budget period.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. Carbon incorporated FeN/C electrocatalyst for oxygen reduction enhancement in direct methanol fuel cells: X-ray absorption approach to local structures

    International Nuclear Information System (INIS)

    Highlights: → Nonprecious iron nitride catalysts demonstrate an excellent anti-methanol crossover performance; it could be benefic for the applications in direct methanol fuel cells (DMFCs). → H2O2 is poorly yielded in the electrochemical test. It could be helpful for a proton exchange membrane, since H2O2 would etch the membrane. → Tafel plot and rotating ring disk electrode (RRDE) both give that electron transfer numbers are close to 4 in oxygen reduction reaction (ORR), indicating the major product as H2O. → Fe-C contributes to the FeCN/C catalyst by using EXAFS analysis. FeCN nanoparticles would disperse on C supports and may give ORR activity. - Abstract: The C-containing iron nitride electrocatalyst is fabricated by chelating N-containing species and Fe2+ with a carbon support under heat treatment in an NH3 atmosphere, which induces the oxygen reduction reaction activity. This is the first demonstration of forming FexC species on iron nitride materials. The correlation between the electrochemical properties and structures are aided to elucidate their features under investigation by using X-ray absorption spectroscopy. A rotating ring disk electrode test is conducted in sulfuric acid solution and the results reveal the low H2O2 yield and approximately 4e- transfer process of the carbon-containing FeN/C electrocatalyst.

  4. 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...

  5. 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

  6. ASSESSMENT OF HOUSEHOLD CARBON FOOTPRINT REDUCTION POTENTIALS

    OpenAIRE

    Masanet, Eric

    2010-01-01

    The term ?household carbon footprint? refers to the total annual carbon emissions associated with household consumption of energy, goods, and services. In this project, Lawrence Berkeley National Laboratory developed a carbon footprint modeling framework that characterizes the key underlying technologies and processes that contribute to household carbon footprints in California and the United States. The approach breaks down the carbon footprint by 35 different household fuel end uses and 3...

  7. 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

  8. 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

  9. 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

  10. 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) 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...

  11. Mesoscopic modeling of cancer photothermal therapy using single-walled carbon nanotubes and near infrared radiation: insights through an off-lattice Monte Carlo approach

    International Nuclear Information System (INIS)

    Single-walled carbon nanotubes (SWNTs) are promising heating agents in cancer photothermal therapy when under near infrared radiation, yet few efforts have been focused on the quantitative understanding of the photothermal energy conversion in biological systems. In this article, a mesoscopic study that takes into account SWNT morphologies (diameter and aspect ratio) and dispersions (orientation and concentration), as well as thermal boundary resistance, is performed by means of an off-lattice Monte Carlo simulation. Results indicate that SWNTs with orientation perpendicular to the laser, smaller diameter and better dispersion have higher heating efficiency in cancer photothermal therapy. Thermal boundary resistances greatly inhibit thermal energy transfer away from SWNTs, thereby affecting their heating efficiency. Through appropriate interfacial modification around SWNTs, compared to the surrounding healthy tissue, a higher temperature of the cancer cell can be achieved, resulting in more effective cancer photothermal therapy. These findings promise to bridge the gap between macroscopic and microscopic computational studies of cancer photothermal therapy. (papers)

  12. Rice husk based porous carbon loaded with silver nanoparticles by a simple and cost-effective approach and their antibacterial activity.

    Science.gov (United States)

    Cui, Jianghu; Yang, Yunhua; Hu, Yonghui; Li, Fangbai

    2015-10-01

    In this paper, we chose rice husk as raw material and synthesized successfully porous carbon loaded with silver nanoparticles (RH-Ag) composites by simple and cost-effective method. The as-prepared RH-Ag composites have a BET-specific surface area of 1996 m(2) g(-1) and result in strong capacity of bacteria adsorption. The result of antibacterial study indicated that the RH-Ag system displayed antibacterial activity that was two times better than pure Ag NPs. Our study demonstrates that the antibacterial activity of RH-Ag composites may be attributed to their strong adsorption ability with bacteria and result in the disorganization of the bacterial membrane ultrastructure. In addition, RH-Ag system was found to be durative slow-releasing of silver ions and biocompatible for human skin keratinocytes cells. In terms of these advantages, the RH-Ag composites have potential application in antibacterial infections and therapy. PMID:26057944

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Waterflooding process using mucilage gum thickeners

    Energy Technology Data Exchange (ETDEWEB)

    Lummus, J.L.

    1967-08-29

    According to the described process, the viscosity of water in a water drive can be increased with a mucilage gum derived from flax meal. This substance has less tendency to be absorbed on clay surfaces than some high molecular weight polymers that have been studied. The water-extracted flax gum can be deactivated with clay to remove the absorbable fraction and the residual solution be used for the ''pusher flood.'' This is said to avoid decreasing permeability around the well bore and keep the solution in contact with the oil at essentially the same viscosity as the injected fluid. (7 claims)

  18. Chemical waterflooding techniques using complex surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Finch, H.D.

    1970-06-02

    A partial complex of an anionic surfactant with a moderate molecular weight amino-nitrogen-containing salt and/or an anionic surfactant plus a low-water solubility N-substituted ammonium salt of an anionic surfactant are capable of enhanced oil recovery in an aqueous slug. The efficiency of a partially complexed system (sodium dodecylbenzene sulfonate and m-toluidine hydrochloride) is 0.9 with respect to the oil recovery capacity of Bryton petroleum sulfonate (molecular weight 430) plus sodium chlorides, as determined by thin layer chromatography. An aqueous slug of a second partially complexed system (mixtures of C/sub 12/-C/sub 15/ hydroformulation alcohol sulfates and aniline hydrochloride) was followed by a sodium chloride slug on a sand pack, reducing the residual oil to 3 percent PV. This surfactant solution is tolerant to at least 0.8M sodium chloride and 0.01M calcium chloride.

  19. 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

  20. Accurate approach for determining fresh-water carbonate (H2CO3(*)) alkalinity, using a single H3PO4 titration point.

    Science.gov (United States)

    Birnhack, Liat; Sabach, Sara; Lahav, Ori

    2012-10-15

    A new, simple and accurate method is introduced for determining H(2)CO(3)(*) alkalinity in fresh waters dominated by the carbonate weak-acid system. The method relies on a single H(3)PO(4) dosage and two pH readings (acidic pH value target: pH~4.0). The computation algorithm is based on the concept that the overall alkalinity mass of a solution does not change upon the addition of a non-proton-accepting species. The accuracy of the new method was assessed batch-wise with both synthetic and actual tap waters and the results were compared to those obtained from two widely used alkalinity analysis methods (titration to pH~4.5 and the Gran titration method). The experimental results, which were deliberately obtained with simple laboratory equipment (glass buret, general-purpose pH electrode, magnetic stirrer) proved the method to be as accurate as the conventional methods at a wide range of alkalinity values (20-400 mg L(-1) as CaCO(3)). Analysis of the relative error attained in the proposed method as a function of the target (acidic) pH showed that at the range 4.0

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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)

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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

  20. 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

  1. Priming of Soil Carbon Decomposition in Two Inner Mongolia Grassland Soils following Sheep Dung Addition: A Study Using 13C Natural Abundance Approach

    Science.gov (United States)

    Ma, Xiuzhi; Ambus, Per; Wang, Shiping; Wang, Yanfen; Wang, Chengjie

    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) 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 deterioration. PMID:24236024

  2. Ultra-thin and uniform coating of vanadium oxide on multiwall carbon nanotubes through solution based approach for high-performance electrochemical supercapacitors

    International Nuclear Information System (INIS)

    Highlights: • Ultra-thin V2O5 deposited on MWCNTs through bottom up approach. • Full utilization of the V2O5 which provide maximum pseudocapacitance while minimizing the electrode resistance. • The ultra-thin layer of V2O5 on highly conductive MWCNTs is favorable for fast ion and electron transfer. -- Abstract: Electrochemical supercapacitors based on metal oxide nanostructures are poised to provide integration of power sources onto electronic devices, but they suffer from poor cycle lifetime, as well as low energy and power density. To tackle these problems, we report a simple, low-cost, safe and broadly applicable hierarchical bottom-up assembly route for the formation of ultrathin (3 nm) vanadium oxide (V2O5) film on conducting MWCNTs. The ultrathin V2O5 shows a very high capacitance of 510 F g−1 and possesses excellent cyclic stability with negligible decrease in specific capacitance after 5000 cycles. The supercapacitor device based on this hierarchical bottom-up assembly exhibit an excellent charge/discharge capability, and energy densities of 16 W h kg−1 at a power density of 800 W kg−1. Such high performances are due to both the high crystallinity and complete accessibility of ultra-thin film of V2O5 to the aqueous electrolyte of 2 M KCl

  3. 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

  4. 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....

  5. 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.

  6. Carbon nanotubes decorating methods

    Directory of Open Access Journals (Sweden)

    A.D. Dobrzańska-Danikiewicz

    2013-06-01

    Full Text Available Purpose: The work is to present and characterise various methods of depositing carbon nanotubes with nanoparticles of precious metals, and also to present the results of own works concerning carbon nanotubes coated with platinum nanoparticles.Design/methodology/approach: Electron transmission and scanning microscopy has been used for imaging the structure and morphology of the nanocomposites obtained and the distribution of nanoparticles on the surface of carbon nanotubes.Findings: The studies carried out with the HRTEM and SEM techniques have confirmed differences in morphology, homogeneity and density of depositing platinum nanoparticles on the surface of carbon nanotubes and its structure.Research limitations/implications: The studies conducted pertained to the process of decorating carbon nanotubes with platinum nanoparticles. Further works are planned aimed at extending the application scope of the newly developed methodology to include the methods of nanotubes decorating with the nanoparticles of other precious metals (mainly palladium and rhodium.Practical implications: CNTs-NPs (Carbon NanoTube-NanoParticles composites can be used as the active elements of sensors featuring high sensitivity, fast action, high selectivity and accuracy, in particular in medicine as cholesterol and glucoses sensors; in the automotive industry for the precision monitoring of working parameters in individual engine components; in environmental conservation to examine CO2, NOx, and CH4 concentrations and for checking leak-tightness and detecting hazardous substances in household and industrial gas installations.Originality/value: The comprehensive characterisation of the methods employed for fabricating nanocomposites consisting of carbon nanotubes deposited with Pt, Pd, Rh, Au, Ag nanoparticles with special consideration to the colloidal process.

  7. 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.

  8. 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...

  9. Carbon emissions intensity ratio: an indicator for an improved carbon labelling scheme

    International Nuclear Information System (INIS)

    This letter proposes a new carbon labelling scheme to improve the visibility of products’ life cycle carbon emissions (sometimes defined as carbon footprint). This approach starts by normalizing carbon emissions data on a common scale of ‘carbon emissions intensity’, and a new indicator ‘carbon emissions intensity ratio’ is generated based upon its ratio to the annual national greenhouse gas emission per gross domestic product. Five ranges (extremely low, low, medium, high and extremely high) are used to represent the level of carbon emissions intensity ratio by a simple diagram with colour gradation. Case examples are presented, in which the carbon emissions intensity ratios of various selected products, both distinct and related, are calculated and compared. The limitations of this approach are then discussed, laying a foundation for further work. (letter)

  10. 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 ...

  11. 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.

  12. mineral sequestration by wollastonite carbonation

    Science.gov (United States)

    Ding, Wenjin; Fu, Liangjie; Ouyang, Jing; Yang, Huaming

    2014-07-01

    In this paper, we demonstrated a new approach to CO2 mineral sequestration using wollastonite carbonation assisted by sulfuric acid and ammonia. Samples were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and 29Si nuclear magnetic resonance. The change in Gibbs free energy from -223 kJ/mol for the leaching reaction of wollastonite to -101 kJ/mol for the carbonation reaction indicated that these two reactions can proceed spontaneously. The leached and carbonated wollastonite showed fibrous bassanite and granular calcium carbonate, respectively, while the crystal structure of pristine wollastonite was destroyed and the majority of the Ca2+ in pristine wollastonite leached. The chemical changes in the phases were monitored during the whole process. A high carbonation rate of 91.1 % could be obtained under the action of sulfuric acid and ammonia at 30 °C at normal atmospheric pressure, indicating its potential use for CO2 sequestration.

  13. 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

  14. Hyphenation of a EC / OC thermal-optical carbon analyzer to photo-ionization time-of-flight mass spectrometry: an off-line aerosol mass spectrometric approach for characterization of primary and secondary particulate matter

    Science.gov (United States)

    Diab, J.; Streibel, T.; Cavalli, F.; Lee, S. C.; Saathoff, H.; Mamakos, A.; Chow, J. C.; Chen, L.-W. A.; Watson, J. G.; Sippula, O.; Zimmermann, R.

    2015-08-01

    Source apportionment and characterization 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 (SOAs) 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 particulate matter (PM) carbon analysis (for elemental / organic carbon, EC / OC) by enabling the investigation of evolved gaseous species with soft and selective (resonance enhanced multi-photon 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 the electron ionization 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 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 thermal breakdown products. In the 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 of PM

  15. Carbon dioxide utilisation in anaerobic digesters as an on-site carbon revalorisation strategy

    OpenAIRE

    Bajón Fernández, Yadira

    2014-01-01

    The increasing carbon footprint of the water and organic waste sectors has led to water utilities to voluntarily include carbon mitigation approaches within their strategic plans and to an increase in research aimed at mitigating carbon dioxide (CO2) emissions. Injection of CO2 in anaerobic digesters (ADs) for its bioconversion into methane (CH4) has been identified as a potential solution. However, previous literature provided limited knowledge of the carbon benefits obtainable and presented...

  16. 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

  17. 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.

  18. 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

  19. Carbon particles

    Science.gov (United States)

    Hunt, Arlon J.

    1984-01-01

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

  20. 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

  1. 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...... corporations construing themselves as able and suitable to manage their emissions, and, additionally, given that the construction of carbon emissions has performative consequences, the underlying practices need to be declassified, i.e. opened for public scrutiny. Hence the paper concludes by arguing for a...

  2. 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...

  3. 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.

  4. 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.

  5. 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)

  6. 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

  7. Carbon Cycling with Nuclear Power

    Science.gov (United States)

    Lackner, Klaus S.

    2011-11-01

    Liquid hydrocarbon fuels like gasoline, diesel or jet fuel are the most efficient ways of delivering energy to the transportation sector, in particular cars, ships and airplanes. Unfortunately, their use nearly unavoidably leads to the emission of carbon dioxide into the atmosphere. Unless an equivalent amount is removed from the air, the carbon dioxide will accumulate and significantly contribute to the man-made greenhouse effect. If fuels are made from biomass, the capture of carbon dioxide is a natural part of the cycle. Here, we discuss technical options for capturing carbon dioxide at much faster rates. We outline the basic concepts, discuss how such capture technologies could be made affordable and show how they could be integrated into a larger system approach. In the short term, the likely source of the hydrocarbon fuels is oil or gas; in the longer term, technologies that can provide energy to remove oxygen from carbon dioxide and water molecules and combine the remaining components into liquid fuels make it possible to recycle carbon between fuels and carbon dioxide in an entirely abiotic process. Here we focus on renewable and nuclear energy options for producing liquid fuels and show how air capture combined with fuel synthesis could be more economic than a transition to electric cars or hydrogen-fueled cars.

  8. 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…

  9. 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.

  10. CarbonSat Constellation

    Science.gov (United States)

    Sun, Wei; Tobehn, Carsten; Ernst, Robert; Bovensmann, Heinrich; Buchwitz, Michael; Burrows, John P.; Notholt, John

    combination with inverse mode