WorldWideScience

Sample records for carbon-constrained world hybrids

  1. Feasibility analysis of nuclear–coal hybrid energy systems from the perspective of low-carbon development

    International Nuclear Information System (INIS)

    Chen, QianQian; Tang, ZhiYong; Lei, Yang; Sun, YuHan; Jiang, MianHeng

    2015-01-01

    Highlights: • We report a nuclear–coal hybrid energy systems. • We address the high-carbon energy resource integrating with a low-carbon energy resource. • We establish a systematic techno-economic model. • Improving both energy and carbon efficiency. • A significantly lower CO 2 emission intensity is achieved by the system. - Abstract: Global energy consumption is expected to increase significantly due to the growth of the economy and population. The utilization of fossil resource, especially coal, will likely be constrained by carbon dioxide emissions, known to be the principal contributor to climate change. Therefore, the world is facing the challenge of how to utilize fossil resource without a large carbon footprint. In the present work, a nuclear–coal hybrid energy system is proposed as a potential solution to the aforementioned challenge. A high-carbon energy such as coal is integrated effectively with a low-carbon energy such as nuclear in a flexible and optimized manner, which is able to generate the chemicals and fuels with low carbon dioxide emissions. The nuclear–coal hybrid energy system is presented in this paper for the detailed analysis. In this case, the carbon resource required by the fuel syntheses and chemical production processes is mainly provided by coal while the hydrogen resource is derived from nuclear energy. Such integration can not only lead to a good balance between carbon and hydrogen, but also improve both energy and carbon efficiencies. More importantly, a significantly lower CO 2 emission intensity is achieved. A systematic techno-economic model is established, and a scenario analysis is carried out on the hybrid system to assess the economic competitiveness based on the considerations of various types of externalities. It is found that with the rising carbon tax and coal price as well as the decreasing cost of nuclear energy, the hybrid energy system will become more and more economically competitive with the

  2. Hybrid real-code ant colony optimisation for constrained mechanical design

    Science.gov (United States)

    Pholdee, Nantiwat; Bureerat, Sujin

    2016-01-01

    This paper proposes a hybrid meta-heuristic based on integrating a local search simplex downhill (SDH) method into the search procedure of real-code ant colony optimisation (ACOR). This hybridisation leads to five hybrid algorithms where a Monte Carlo technique, a Latin hypercube sampling technique (LHS) and a translational propagation Latin hypercube design (TPLHD) algorithm are used to generate an initial population. Also, two numerical schemes for selecting an initial simplex are investigated. The original ACOR and its hybrid versions along with a variety of established meta-heuristics are implemented to solve 17 constrained test problems where a fuzzy set theory penalty function technique is used to handle design constraints. The comparative results show that the hybrid algorithms are the top performers. Using the TPLHD technique gives better results than the other sampling techniques. The hybrid optimisers are a powerful design tool for constrained mechanical design problems.

  3. Evolutionary constrained optimization

    CERN Document Server

    Deb, Kalyanmoy

    2015-01-01

    This book makes available a self-contained collection of modern research addressing the general constrained optimization problems using evolutionary algorithms. Broadly the topics covered include constraint handling for single and multi-objective optimizations; penalty function based methodology; multi-objective based methodology; new constraint handling mechanism; hybrid methodology; scaling issues in constrained optimization; design of scalable test problems; parameter adaptation in constrained optimization; handling of integer, discrete and mix variables in addition to continuous variables; application of constraint handling techniques to real-world problems; and constrained optimization in dynamic environment. There is also a separate chapter on hybrid optimization, which is gaining lots of popularity nowadays due to its capability of bridging the gap between evolutionary and classical optimization. The material in the book is useful to researchers, novice, and experts alike. The book will also be useful...

  4. Electricity in a Climate-Constrained World

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    After experiencing a historic drop in 2009, electricity generation reached a record high in 2010, confirming the close linkage between economic growth and electricity usage. Unfortunately, CO2 emissions from electricity have also resumed their growth: Electricity remains the single-largest source of CO2 emissions from energy, with 11.7 billion tonnes of CO2 released in 2010. The imperative to 'decarbonise' electricity and improve end-use efficiency remains essential to the global fight against climate change. The IEA’s Electricity in a Climate-Constrained World provides an authoritative resource on progress to date in this area, including statistics related to CO2 and the electricity sector across ten regions of the world (supply, end-use and capacity additions). It also presents topical analyses on the challenge of rapidly curbing CO2 emissions from electricity. Looking at policy instruments, it focuses on emissions trading in China, using energy efficiency to manage electricity supply crises and combining policy instruments for effective CO2 reductions. On regulatory issues, it asks whether deregulation can deliver decarbonisation and assesses the role of state-owned enterprises in emerging economies. And from technology perspectives, it explores the rise of new end-uses, the role of electricity storage, biomass use in Brazil, and the potential of carbon capture and storage for ‘negative emissions’ electricity supply.

  5. Constrained Optimization Based on Hybrid Evolutionary Algorithm and Adaptive Constraint-Handling Technique

    DEFF Research Database (Denmark)

    Wang, Yong; Cai, Zixing; Zhou, Yuren

    2009-01-01

    A novel approach to deal with numerical and engineering constrained optimization problems, which incorporates a hybrid evolutionary algorithm and an adaptive constraint-handling technique, is presented in this paper. The hybrid evolutionary algorithm simultaneously uses simplex crossover and two...... mutation operators to generate the offspring population. Additionally, the adaptive constraint-handling technique consists of three main situations. In detail, at each situation, one constraint-handling mechanism is designed based on current population state. Experiments on 13 benchmark test functions...... and four well-known constrained design problems verify the effectiveness and efficiency of the proposed method. The experimental results show that integrating the hybrid evolutionary algorithm with the adaptive constraint-handling technique is beneficial, and the proposed method achieves competitive...

  6. Managing Deadline-constrained Bag-of-Tasks Jobs on Hybrid Clouds

    OpenAIRE

    Wang, Bo; Song, Ying; Sun, Yuzhong; Liu, Jun

    2016-01-01

    Outsourcing jobs to a public cloud is a cost-effective way to address the problem of satisfying the peak resource demand when the local cloud has insufficient resources. In this paper, we study on managing deadline-constrained bag-of-tasks jobs on hybrid clouds. We present a binary nonlinear programming (BNP) problem to model the hybrid cloud management where the utilization of physical machines (PMs) in the local cloud/cluster is maximized when the local resources are enough to satisfy the d...

  7. A comparative economic assessment of hydrogen production from large central versus smaller distributed plant in a carbon constrained world

    International Nuclear Information System (INIS)

    Nguyen, Y.V.; Ngo, Y.A.; Tinkler, M.J.; Cowan, N.

    2003-01-01

    This paper compares the economics of producing hydrogen at large central plants versus smaller distributed plants at user sites. The economics of two types of central plant, each at 100 million standard cubic feet per day of hydrogen, based on electrolysis and natural gas steam reforming technologies, will be discussed. The additional cost of controlling CO 2 emissions from the natural gas steam reforming plant will be included in the analysis in order to satisfy the need to live in a future carbon constrained world. The cost of delivery of hydrogen from the large central plant to the user sites in a large metropolitan area will be highlighted, and the delivered cost will be compared to the cost from on-site distributed generation plants. Five types of distributed generation plants, based on proton exchange membrane, alkaline electrolysis and advanced steam reforming, will be analysed and discussed. Two criteria were used to rank various hydrogen production options, the cost of production and the price of hydrogen to achieve an acceptable return of investment. (author)

  8. Hybrid-Electric Passenger Car Carbon Dioxide and Fuel Consumption Benefits Based on Real-World Driving.

    Science.gov (United States)

    Holmén, Britt A; Sentoff, Karen M

    2015-08-18

    Hybrid-electric vehicles (HEVs) have lower fuel consumption and carbon dioxide (CO2) emissions than conventional vehicles (CVs), on average, based on laboratory tests, but there is a paucity of real-world, on-road HEV emissions and performance data needed to assess energy use and emissions associated with real-world driving, including the effects of road grade. This need is especially great as the electrification of the passenger vehicle fleet (from HEVs to PHEVs to BEVs) increases in response to climate and energy concerns. We compared tailpipe CO2 emissions and fuel consumption of an HEV passenger car to a CV of the same make and model during real-world, on-the-road network driving to quantify the in-use benefit of one popular full HEV technology. Using vehicle specific power (VSP) assignments that account for measured road grade, the mean CV/HEV ratios of CO2 tailpipe emissions or fuel consumption defined the corresponding HEV "benefit" factor for each VSP class (1 kW/ton resolution). Averaging over all VSP classes for driving in all seasons, including temperatures from -13 to +35 °C in relatively steep (-13.2 to +11.5% grade), hilly terrain, mean (±SD) CO2 emission benefit factors were 4.5 ± 3.6, 2.5 ± 1.7, and 1.4 ± 0.5 for city, exurban/suburban arterial and highway driving, respectively. Benefit factor magnitude corresponded to the frequency of electric-drive-only (EDO) operation, which was modeled as a logarithmic function of VSP. A combined model explained 95% of the variance in HEV benefit for city, 75% for arterial and 57% for highway driving. Benefit factors consistently exceeded 2 for VSP classes with greater than 50% EDO (i.e., only city and arterial driving). The reported HEV benefits account for real-world road grade that is often neglected in regulatory emissions and fuel economy tests. Fuel use HEV benefit factors were 1.3 and 2 for the regulatory highway (HWFET) and city (FTP) cycles, respectively, 18% and 31% higher than the EPA adjusted

  9. Algorithm for locating the extremum of a multi-dimensional constrained function and its application to the PPPL Hybrid Study

    International Nuclear Information System (INIS)

    Bathke, C.

    1978-03-01

    A description is presented of a general algorithm for locating the extremum of a multi-dimensional constrained function. The algorithm employs a series of techniques dominated by random shrinkage, steepest descent, and adaptive creeping. A discussion follows of the algorithm's application to a ''real world'' problem, namely the optimization of the price of electricity, P/sub eh/, from a hybrid fusion-fission reactor. Upon the basis of comparisons with other optimization schemes of a survey nature, the algorithm is concluded to yield a good approximation to the location of a function's optimum

  10. Impact of fusion-fission hybrids on world nuclear future

    International Nuclear Information System (INIS)

    Abdel-Khalick, S.; Jansen, P.; Kessler, G.; Klumpp, P.

    1980-08-01

    An investigation has been conducted to examine the impact of fusion-fission hybrids on world nuclear future. The primary objectives of this investigation have been: (1) to determine whether hybrids can allow us to meet the projected nuclear component of the world energy demand within current estimates of uranium resources without fast breeders, and (2) to identify the preferred hybrid concept from a resource standpoint. The results indicate that hybrids have the potential to lower the world uranium demand to values well below the resource base. However, the time window for hybrid introduction is quite near and narrow (2000-2020). If historical market penetration rates are assumed, the demand will not be met within the resource base unless hybrids are coupled to the breeders. The results also indicate that from a resource standpoint hybrids which breed their own tritium and have a low blanket energy multiplication are preferable. (orig.) [de

  11. Oil sands development in a carbon constrained world

    Energy Technology Data Exchange (ETDEWEB)

    McDougall, J. [Alberta Research Council, Devon, AB (Canada)

    2006-07-01

    The challenges facing oilsands development in Alberta were discussed in this PowerPoint presentation. In 2005, 71 per cent of Alberta's export value was derived from energy and mining. The author addressed the issue that resource based economies have rarely succeeded in the long term. He then demonstrated how such economies could capture value from technology. The primary focus was on the goal to develop and adapt greenhouse gas (GHG) transformational technologies that will break the link between hydrocarbon energy use and GHG emissions. The role of oil sands in this endeavour was also discussed. Alberta's oil sands are the world's largest hydrocarbon resource, with 315 b bbls proven reserves, and 2.5 t bbls potential reserves. As an important economic driver for Alberta, oil sands production is expected to grow significantly in the next 2 decades. Since bitumen production is more energy intensive than conventional oil, the industry is faced with the challenge of sustainable development. Concentrated GHG emissions create opportunities to proceed with long-term oil sands development with a sustainable level of GHG emissions, but technology and infrastructure are needed to take advantage of them. Current carbon dioxide (CO{sub 2}) storage projects in Alberta were highlighted. The economic potential of geological storage of CO{sub 2} through acid gas injection or deep disposal was discussed in terms of enhanced oil recovery, enhanced coalbed methane recovery, enhanced gas recovery and cost avoidance of CO{sub 2} per tonne. It was emphasized that a long-term vision and commitment is needed to balance with short term problems solving and longer-term strategic agendas. tabs., figs.

  12. Impact of fusion-fission hybrids on world nuclear future

    International Nuclear Information System (INIS)

    Abdel-Khalik, S.I.; Jansen, P.; Kessler, G.; Klumpp, P.

    1981-01-01

    An investigation has been conducted to examine the impact of fusion-fission hybrids on world nuclear future. The primary objectives of this investigation have been: (1) to determine whether hybrids can allow us to meet the projected nuclear component of the world energy demand within current estimates of uranium resources with or without fast breeders, and (2) to identify the preferred hybrid concept from a resource standpoint. The results indicate that hybrids have the potential to lower the world uranium demand to values well below the resource base. However, the time window for hybrid introduction is quite near and narrow (2000-2020). If historical market penetration rates are assumed, the demand will not be met within the resource base unless hybrids are coupled to the breeders. The results also indicate that from a resource standpoint hybrids which breed their own tritium and have a low blanket energy multiplication are preferable. (orig.) [de

  13. Impact of fusion-fission hybrids on world nuclear future

    International Nuclear Information System (INIS)

    Abdel-Khalik, S.I.

    1980-01-01

    An investigation has been conducted to examine the impact of fusion-fission hybrids on world nuclear future. The primary objectives of this investigation have been (1) to determine whether hybrids can allow us to meet the projected nuclear component of the world energy demand within current estimates of uranium resources with or without fast breeders, and (2) to identify the preferred hybrid concept from a resource standpoint. The results indicate that hybrids have the potential to lower the world uranium demand to values well below the resource base. However, the time window for hybrid introduction is quite near and narrow (2000-2020). If historical market penetration rates are assumed, the demand will not be met within the resource base unless hybrides are coupled to the breeders. The results also indicate that from a resource standpaint hybrids which breed their own tritium and have a low blanket energy multiplication are preferable. (orig.) [de

  14. Poverty eradication in a carbon constrained world.

    Science.gov (United States)

    Hubacek, Klaus; Baiocchi, Giovanni; Feng, Kuishuang; Patwardhan, Anand

    2017-10-24

    The UN Framework Convention on Climate Change aims to keep warming below 2 °C while recognizing developing countries' right to eradicate extreme poverty. Poverty eradication is also the first of the Sustainable Development Goals. This paper investigates potential consequences for climate targets of achieving poverty eradication. We find that eradicating extreme poverty, i.e., moving people to an income above $1.9 purchasing power parity (PPP) a day, does not jeopardize the climate target even in the absence of climate policies and with current technologies. On the other hand, bringing everybody to a still modest expenditure level of at least $2.97 PPP would have long-term consequences on achieving emission targets. Compared to the reference mitigation pathway, eradicating extreme poverty increases the effort by 2.8% whereas bringing everybody to at least $2.97 PPP would increase the required mitigation rate by 27%. Given that the top 10% global income earners are responsible for 36% of the current carbon footprint of households; the discourse should address income distribution and the carbon intensity of lifestyles.

  15. The economics and environmental impacts of large-scale wind power in a carbon constrained world

    Science.gov (United States)

    Decarolis, Joseph Frank

    Serious climate change mitigation aimed at stabilizing atmospheric concentrations of CO2 will require a radical shift to a decarbonized energy supply. The electric power sector will be a primary target for deep reductions in CO2 emissions because electric power plants are among the largest and most manageable point sources of emissions. With respect to new capacity, wind power is currently one of the most inexpensive ways to produce electricity without CO2 emissions and it may have a significant role to play in a carbon constrained world. Yet most research in the wind industry remains focused on near term issues, while energy system models that focus on century-long time horizons undervalue wind by imposing exogenous limits on growth. This thesis fills a critical gap in the literature by taking a closer look at the cost and environmental impacts of large-scale wind. Estimates of the average cost of wind generation---now roughly 4¢/kWh---do not address the cons arising from the spatial distribution and intermittency of wind. This thesis develops a theoretical framework for assessing the intermittency cost of wind. In addition, an economic characterization of a wind system is provided in which long-distance electricity transmission, storage, and gas turbines are used to supplement variable wind power output to meet a time-varying load. With somewhat optimistic assumptions about the cost of wind turbines, the use of wind to serve 50% of demand adds ˜1--2¢/kWh to the cost of electricity, a cost comparable to that of other large-scale low carbon technologies. This thesis also explores the environmental impacts posed by large-scale wind. Though avian mortality and noise caused controversy in the early years of wind development, improved technology and exhaustive siting assessments have minimized their impact. The aesthetic valuation of wind farms can be improved significantly with better design, siting, construction, and maintenance procedures, but opposition may

  16. Multiscale Hybrid Micro-Nanocomposites Based on Carbon Nanotubes and Carbon Fibers

    Directory of Open Access Journals (Sweden)

    Fawad Inam

    2010-01-01

    Full Text Available Amino-modified double wall carbon nanotube (DWCNT-NH2/carbon fiber (CF/epoxy hybrid micro-nanocomposite laminates were prepared by a resin infusion technique. DWCNT-NH2/epoxy nanocomposites and carbon fiber/epoxy microcomposites were made for comparison. Morphological analysis of the hybrid composites was performed using field emission scanning electron microscope. A good dispersion at low loadings of carbon nanotubes (CNTs in epoxy matrix was achieved by a bath ultrasonication method. Mechanical characterization of the hybrid micro-nanocomposites manufactured by a resin infusion process included three-point bending, mode I interlaminar toughness, dynamic mechanical analysis, and drop-weight impact testing. The addition of small amounts of CNTs (0.025, 0.05, and 0.1 wt% to epoxy resins for the fabrication of multiscale carbon fiber composites resulted in a maximum enhancement in flexural modulus by 35%, a 5% improvement in flexural strength, a 6% improvement in absorbed impact energy, and 23% decrease in the mode I interlaminar toughness. Hybridization of carbon fiber-reinforced epoxy using CNTs resulted in a reduction in and dampening characteristics, presumably as a result of the presence of micron-sized agglomerates.

  17. Thermal Properties of Hybrid Carbon Nanotube/Carbon Fiber Polymer

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Luong, Hoa; Ratcliffe, James G.; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    Carbon fiber reinforced polymer (CFRP) composites possess many advantages for aircraft structures over conventional aluminum alloys: light weight, higher strength- and stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low thermal and electrical conductivities of CFRP composites are deficient in providing structural safety under certain operational conditions such as lightning strikes. One possible solution to these issues is to interleave carbon nanotube (CNT) sheets between conventional carbon fiber (CF) composite layers. However, the thermal and electrical properties of the orthotropic hybrid CNT/CF composites have not been fully understood. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel (Registered Trademark) IM7/8852 prepreg. The CNT sheets were infused with a 5% solution of a compatible epoxy resin prior to composite fabrication. Orthotropic thermal and electrical conductivities of the hybrid polymer composites were evaluated. The interleaved CNT sheets improved the in-plane thermal conductivity of the hybrid composite laminates by about 400% and the electrical conductivity by about 3 orders of magnitude.

  18. Carbon-constrained scenarios. Final report

    International Nuclear Information System (INIS)

    2009-05-01

    This report provides the results of the study entitled 'Carbon-Constrained Scenarios' that was funded by FONDDRI from 2004 to 2008. The study was achieved in four steps: (i) Investigating the stakes of a strong carbon constraint for the industries participating in the study, not only looking at the internal decarbonization potential of each industry but also exploring the potential shifts of the demand for industrial products. (ii) Developing an hybrid modelling platform based on a tight dialog between the sectoral energy model POLES and the macro-economic model IMACLIM-R, in order to achieve a consistent assessment of the consequences of an economy-wide carbon constraint on energy-intensive industrial sectors, while taking into account technical constraints, barriers to the deployment of new technologies and general economic equilibrium effects. (iii) Producing several scenarios up to 2050 with different sets of hypotheses concerning the driving factors for emissions - in particular the development styles. (iv) Establishing an iterative dialog between researchers and industry representatives on the results of the scenarios so as to improve them, but also to facilitate the understanding and the appropriate use of these results by the industrial partners. This report provides the results of the different scenarios computed in the course of the project. It is a partial synthesis of the work that has been accomplished and of the numerous exchanges that this study has induced between modellers and stakeholders. The first part was written in April 2007 and describes the first reference scenario and the first mitigation scenario designed to achieve stabilization at 450 ppm CO 2 at the end of the 21. century. This scenario has been called 'mimetic' because it has been build on the assumption that the ambitious climate policy would coexist with a progressive convergence of development paths toward the current paradigm of industrialized countries: urban sprawl, general

  19. Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Ratcliffe, James G.; Luong, Hoa; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strengthand stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Despite several attempts to solve these issues with the addition of carbon nanotubes (CNT) into polymer matrices, and/or by interleaving CNT sheets between conventional carbon fiber (CF) composite layers, there are still interfacial problems that exist between CNTs (or CF) and the resin. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing (double cantilever beam and end-notched flexure test). Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated. Interleaving CNT sheets significantly improved the in-plane (axial and perpendicular direction of CF alignment) thermal conductivity of the hybrid composite laminates by 50 - 400%.

  20. Preparation and characterization of carbon nanotube-hybridized carbon fiber to reinforce epoxy composite

    International Nuclear Information System (INIS)

    An, Feng; Lu, Chunxiang; Li, Yonghong; Guo, Jinhai; Lu, Xiaoxuan; Lu, Huibin; He, Shuqing; Yang, Yu

    2012-01-01

    Highlights: → CNTs were uniformly grown onto the carbon fibers. → No obvious mechanical properties of carbon fiber were observed after CNT growth. → The IFSS of multiscale epoxy composite was measured by single fiber pull-out tests. → Observing fractography of composite, the fracture modes of CNTs were discussed. -- Abstract: The multiscale carbon nanotube-hybridized carbon fiber was prepared by a newly developed aerosol-assisted chemical vapour deposition. Scanning electron microscopy and transmission electron microscope were carried out to characterize this multiscale material. Compared with the original carbon fibers, the fabrication of this hybrid fiber resulted in an almost threefold increase of BET surface area to reach 2.22 m 2 /g. Meanwhile, there was a slight degradation of fiber tensile strength within 10%, while the fiber modulus was not significantly affected. The interfacial shearing strength of a carbon fiber-reinforced polymer composite with carbon nanotube-hybridized carbon fiber and an epoxy matrix was determined from the single fiber pull-out tests of microdroplet composite. Due to an efficient increase of load transfer at the fiber/matrix interfaces, the interracial shear strength of composite reinforced by carbon nanotube-hybridized carbon fiber is almost 94% higher than that of one reinforced by the original carbon fiber. Based on the fractured morphologies of the composites, the interfacial reinforcing mechanisms were discussed through proposing different types of carbon nanotube fracture modes along with fiber pulling out from epoxy composites.

  1. Bioenergy and the importance of land use policy in a carbon-constrained world

    Energy Technology Data Exchange (ETDEWEB)

    Calvin, Katherine V.; Edmonds, James A.; Wise, Marshall A.

    2010-06-01

    Policies aimed at limiting anthropogenic climate change would result in significant transformations of the energy and land-use systems. However, increasing the demand for bioenergy could have a tremendous impact on land use, and can result in land clearing and deforestation. Wise et al. (2009a,b) analyzed an idealized policy to limit the indirect land use change emissions from bioenergy. The policy, while effective, would be difficult, if not impossible, to implement in the real world. In this paper, we consider several different land use policies that deviate from this first-best, using the Joint Global Change Research Institute’s Global Change Assessment Model (GCAM). Specifically, these new frameworks are (1) a policy that focuses on just the above-ground or vegetative terrestrial carbon rather than the total carbon, (2) policies that focus exclusively on incentivizing and protecting forestland, and (3) policies that apply an economic penalty on the use of biomass as a proxy to limit indirect land use change emissions. For each policy, we examine its impact on land use, land-use change emissions, atmospheric CO2 concentrations, agricultural supply, and food prices.

  2. Non-covalently functionalized carbon nanostructures for synthesizing carbon-based hybrid nanomaterials.

    Science.gov (United States)

    Li, Haiqing; Song, Sing I; Song, Ga Young; Kim, Il

    2014-02-01

    Carbon nanostructures (CNSs) such as carbon nanotubes, graphene sheets, and nanodiamonds provide an important type of substrate for constructing a variety of hybrid nanomaterials. However, their intrinsic chemistry-inert surfaces make it indispensable to pre-functionalize them prior to immobilizing additional components onto their surfaces. Currently developed strategies for functionalizing CNSs include covalent and non-covalent approaches. Conventional covalent treatments often damage the structure integrity of carbon surfaces and adversely affect their physical properties. In contrast, the non-covalent approach offers a non-destructive way to modify CNSs with desired functional surfaces, while reserving their intrinsic properties. Thus far, a number of surface modifiers including aromatic compounds, small-molecular surfactants, amphiphilic polymers, and biomacromolecules have been developed to non-covalently functionalize CNS surfaces. Mediated by these surface modifiers, various functional components such as organic species and inorganic nanoparticles were further decorated onto their surfaces, resulting in versatile carbon-based hybrid nanomaterials with broad applications in chemical engineering and biomedical areas. In this review, the recent advances in the generation of such hybrid nanostructures based on non-covalently functionalized CNSs will be reviewed.

  3. Strongly coupled inorganic-nano-carbon hybrid materials for energy storage.

    Science.gov (United States)

    Wang, Hailiang; Dai, Hongjie

    2013-04-07

    The global shift of energy production from fossil fuels to renewable energy sources requires more efficient and reliable electrochemical energy storage devices. In particular, the development of electric or hydrogen powered vehicles calls for much-higher-performance batteries, supercapacitors and fuel cells than are currently available. In this review, we present an approach to synthesize electrochemical energy storage materials to form strongly coupled hybrids (SC-hybrids) of inorganic nanomaterials and novel graphitic nano-carbon materials such as carbon nanotubes and graphene, through nucleation and growth of nanoparticles at the functional groups of oxidized graphitic nano-carbon. We show that the inorganic-nano-carbon hybrid materials represent a new approach to synthesize electrode materials with higher electrochemical performance than traditional counterparts made by simple physical mixtures of electrochemically active inorganic particles and conducting carbon materials. The inorganic-nano-carbon hybrid materials are novel due to possible chemical bonding between inorganic nanoparticles and oxidized carbon, affording enhanced charge transport and increased rate capability of electrochemical materials without sacrificing specific capacity. Nano-carbon with various degrees of oxidation provides a novel substrate for nanoparticle nucleation and growth. The interactions between inorganic precursors and oxidized-carbon substrates provide a degree of control over the morphology, size and structure of the resulting inorganic nanoparticles. This paper reviews the recent development of inorganic-nano-carbon hybrid materials for electrochemical energy storage and conversion, including the preparation and functionalization of graphene sheets and carbon nanotubes to impart oxygen containing groups and defects, and methods of synthesis of nanoparticles of various morphologies on oxidized graphene and carbon nanotubes. We then review the applications of the SC-hybrid

  4. Graphene-carbon nanotube hybrid materials and use as electrodes

    Science.gov (United States)

    Tour, James M.; Zhu, Yu; Li, Lei; Yan, Zheng; Lin, Jian

    2016-09-27

    Provided are methods of making graphene-carbon nanotube hybrid materials. Such methods generally include: (1) associating a graphene film with a substrate; (2) applying a catalyst and a carbon source to the graphene film; and (3) growing carbon nanotubes on the graphene film. The grown carbon nanotubes become covalently linked to the graphene film through carbon-carbon bonds that are located at one or more junctions between the carbon nanotubes and the graphene film. In addition, the grown carbon nanotubes are in ohmic contact with the graphene film through the carbon-carbon bonds at the one or more junctions. The one or more junctions may include seven-membered carbon rings. Also provided are the formed graphene-carbon nanotube hybrid materials.

  5. Hybrid carbon incentive mechanisms and political acceptability

    International Nuclear Information System (INIS)

    Vollebergh, H.R.J.; De Vries, J.L.; Koutstaal, P.R.

    1997-01-01

    In this paper it is analyzed how hybrid systems of carbon taxes and tradeable permits optimize some conflicting dimensions of political acceptability related to the design of these instruments. Pure systems like taxes without exemptions or auctioned tradeable permits cause problems for political acceptability in open economies due to high overall costs (abatement cost plus payments on the tax or auctions) for current polluters. Unfortunately, pure systems based on grandfathering of emission rights across the board do not provide a feasible alternative because of monitoring and enforcement problems. In contrast, consciously designed hybrid systems employ grandfathering of emission rights together with either carbon taxes or auctioned carbon permits in order to overcome acceptability problems of pure systems, while leaving incentives to reduce emissions at the margin untouched. Moreover, monitoring and enforcement costs of the hybrid systems are less due to the lower number of participating agents compared with the pure systems, while opportunities for cost- or burden-sharing exist as well. 3 figs., 4 tabs., 23 refs

  6. Photoresponse of hybrids made of carbon nanotubes and CdTe nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Zebli, Bernd; Vieyra, Hugo A.; Kotthaus, Joerg P. [Department fuer Physik and Center for NanoScience (CeNS), Ludwig-Maximilians-Universitaet Muenchen, Geschwister-Scholl-Platz 1, 80539 Munich (Germany); Carmeli, Itai [Department of Chemistry and Biochemistry, Tel-Aviv University, Tel-Aviv 69978 (Israel); Hartschuh, Achim [Department fuer Chemie, Physikalische Chemie, Butenandtstr. 5-13 E, 81377 Munich (Germany); Holleitner, Alexander W. [Walter-Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, 85748 Garching (Germany)

    2008-07-01

    We observe that the photoresponse of single-walled carbon nanotubes can be adjusted by the absorption characteristics of colloidal CdTe nanocrystals, which are bound to the side-walls of the carbon nanotubes via molecular recognition. To this end, the hybrid systems are characterized using charge transport measurements under resonant optical excitation of the carbon nanotubes and nanocrystals, respectively. We investigate the photoresponse of both ensembles of hybrid systems and single carbon-nanotube-nanocrystal-hybrids. The data suggest a bolometrically induced increase of the current in the carbon nanotubes, which is due to photon absorption in the nanocrystals.

  7. Core-shell LiFePO4 /carbon-coated reduced graphene oxide hybrids for high-power lithium-ion battery cathodes.

    Science.gov (United States)

    Ha, Sung Hoon; Lee, Yun Jung

    2015-01-26

    Core-shell carbon-coated LiFePO4 nanoparticles were hybridized with reduced graphene (rGO) for high-power lithium-ion battery cathodes. Spontaneous aggregation of hydrophobic graphene in aqueous solutions during the formation of composite materials was precluded by employing hydrophilic graphene oxide (GO) as starting templates. The fabrication of true nanoscale carbon-coated LiFePO4 -rGO (LFP/C-rGO) hybrids were ascribed to three factors: 1) In-situ polymerization of polypyrrole for constrained nanoparticle synthesis of LiFePO4 , 2) enhanced dispersion of conducting 2D networks endowed by colloidal stability of GO, and 3) intimate contact between active materials and rGO. The importance of conducting template dispersion was demonstrated by contrasting LFP/C-rGO hybrids with LFP/C-rGO composites in which agglomerated rGO solution was used as the starting templates. The fabricated hybrid cathodes showed superior rate capability and cyclability with rates from 0.1 to 60 C. This study demonstrated the synergistic combination of nanosizing with efficient conducting templates to afford facile Li(+) ion and electron transport for high power applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Optimal Design for Hybrid Ratio of Carbon/Basalt Hybrid Fiber Reinforced Resin Matrix Composites

    Directory of Open Access Journals (Sweden)

    XU Hong

    2017-08-01

    Full Text Available The optimum hybrid ratio range of carbon/basalt hybrid fiber reinforced resin composites was studied. Hybrid fiber composites with nine different hybrid ratios were prepared before tensile test.According to the structural features of plain weave, the unit cell's performance parameters were calculated. Finite element model was established by using SHELL181 in ANSYS. The simulated values of the sample stiffness in the model were approximately similar to the experimental ones. The stress nephogram shows that there is a critical hybrid ratio which divides the failure mechanism of HFRP into single failure state and multiple failure state. The tensile modulus, strength and limit tensile strain of HFRP with 45% resin are simulated by finite element method. The result shows that the tensile modulus of HFRP with 60% hybrid ratio increases by 93.4% compared with basalt fiber composites (BFRP, and the limit tensile strain increases by 11.3% compared with carbon fiber composites(CFRP.

  9. Modification of the Interfacial Interaction between Carbon Fiber and Epoxy with Carbon Hybrid Materials

    Directory of Open Access Journals (Sweden)

    Kejing Yu

    2016-05-01

    Full Text Available The mechanical properties of the hybrid materials and epoxy and carbon fiber (CF composites were improved significantly as compared to the CF composites made from unmodified epoxy. The reasons could be attributed to the strong interfacial interaction between the CF and the epoxy composites for the existence of carbon nanomaterials. The microstructure and dispersion of carbon nanomaterials were characterized by transmission electron microscopy (TEM and optical microscopy (OM. The results showed that the dispersion of the hybrid materials in the polymer was superior to other carbon nanomaterials. The high viscosity and shear stress characterized by a rheometer and the high interfacial friction and damping behavior characterized by dynamic mechanical analysis (DMA indicated that the strong interfacial interaction was greatly improved between fibers and epoxy composites. Remarkably, the tensile tests presented that the CF composites with hybrid materials and epoxy composites have a better reinforcing and toughening effect on CF, which further verified the strong interfacial interaction between epoxy and CF for special structural hybrid materials.

  10. Scenarios for transition towards a low-carbon world in 2050: What's at stake for heavy industries?

    International Nuclear Information System (INIS)

    2008-11-01

    Launched in 2004, the study Scenarios for transition towards a low-carbon world in 2050: What's at stake for heavy industries explores how major industrial sectors will be impacted by a carbon constraint stabilizing atmospheric CO 2 concentration at 450 ppm. By means of an innovative hybrid modelling platform and ongoing dialogue between researchers and industrialists, the study produces conclusions concerning both general climate policy as well as the economic response of industrial sectors - specifically of the steel, aluminium, cement, and sheet glass sectors, as well as of the energy sector. (authors)

  11. The geopolitics of oil in a carbon-constrained world

    OpenAIRE

    Verbruggen, Aviel; Van de Graaf, Thijs

    2015-01-01

    Aviel Verbruggen and Thijs Van de Graaf posit that the dominant view of oil geopolitics as a struggle over scarce reserves is lopsided. Assuming that strict carbon limits will be imposed as a result of expected climate change, they believe oil markets will face a structural glut. The geopolitics of oil revolves around abundance-induced conflict, with rival oil producers competing to serve the shrinking oil market.

  12. 3D hybrid-porous carbon derived from carbonization of metal organic frameworks for high performance supercapacitors

    Science.gov (United States)

    Bao, Weizhai; Mondal, Anjon Kumar; Xu, Jing; Wang, Chengyin; Su, Dawei; Wang, Guoxiu

    2016-09-01

    We report a rational design and synthesis of 3D hybrid-porous carbon with a hierarchical pore architecture for high performance supercapacitors. It contains micropores (<2 nm diameter) and mesopores (2-4 nm), derived from carbonization of unique porous metal organic frameworks (MOFs). Owning to the synergistic effect of micropores and mesopores, the hybrid-porous carbon has exceptionally high ion-accessible surface area and low ion diffusion resistance, which is desired for supercapacitor applications. When applied as electrode materials in supercapacitors, 3D hybrid-porous carbon demonstrates a specific capacitance of 332 F g-1 at a constant charge/discharge current of 500 mA g-1. The supercapacitors can endure more than 10,000 cycles without degradation of capacitance.

  13. Carbon nanotube TiO2 hybrid films for detecting traces of O2

    Science.gov (United States)

    Llobet, E.; Espinosa, E. H.; Sotter, E.; Ionescu, R.; Vilanova, X.; Torres, J.; Felten, A.; Pireaux, J. J.; Ke, X.; Van Tendeloo, G.; Renaux, F.; Paint, Y.; Hecq, M.; Bittencourt, C.

    2008-09-01

    Hybrid titania films have been prepared using an adapted sol-gel method for obtaining well-dispersed hydrogen plasma-treated multiwall carbon nanotubes in either pure titania or Nb-doped titania. The drop-coating method has been used to fabricate resistive oxygen sensors based on titania or on titania and carbon nanotube hybrids. Morphology and composition studies have revealed that the dispersion of low amounts of carbon nanotubes within the titania matrix does not significantly alter its crystallization behaviour. The gas sensitivity studies performed on the different samples have shown that the hybrid layers based on titania and carbon nanotubes possess an unprecedented responsiveness towards oxygen (i.e. more than four times higher than that shown by optimized Nb-doped TiO2 films). Furthermore, hybrid sensors containing carbon nanotubes respond at significantly lower operating temperatures than their non-hybrid counterparts. These new hybrid sensors show a strong potential for monitoring traces of oxygen (i.e. beverage industry.

  14. Applications of Novel Carbon/AlPO4 Hybrid-Coated H2Ti12O25 as a High-Performance Anode for Cylindrical Hybrid Supercapacitors.

    Science.gov (United States)

    Lee, Jeong-Hyun; Lee, Seung-Hwan

    2016-10-26

    The hybrid supercapacitor using carbon/AlPO 4 hybrid-coated H 2 Ti 12 O 25 /activated carbon is fabricated as a cylindrical cell and investigated against electrochemical performances. The hybrid coating shows that the conductivity for the electron and Li ion is superior and it prevented active material from HF attack. Consequently, carbon/AlPO 4 hybrid-coated H 2 Ti 12 O 25 shows enhanced rate capability and long-term cycle life. Also, the hybrid coating inhibits swelling phenomenon caused by gas generated as decomposition reaction of electrolyte. Therefore, the hybrid supercapacitor using carbon/AlPO 4 hybrid-coated H 2 Ti 12 O 25 /activated carbon can be applied to an energy storage system that requires a long-term life.

  15. Flexural Progressive Failure of Carbon/Glass Interlayer and Intralayer Hybrid Composites.

    Science.gov (United States)

    Wang, Qingtao; Wu, Weili; Gong, Zhili; Li, Wei

    2018-04-17

    The flexural progressive failure modes of carbon fiber and glass fiber (C/G) interlayer and intralayer hybrid composites were investigated in this work. Results showed that the bending failure modes for interlayer hybrid composites are determined by the layup structure. Besides, the bending failure is characterized by the compression failure of the upper layer, when carbon fiber tends to distribute in the upper layer, the interlayer hybrid composite fails early, the failure force is characterized by a multi-stage slightly fluctuating decline and the fracture area exhibits a diamond shape. While carbon fiber distributes in the middle or bottom layer, the failure time starts late, and the failure process exhibits one stage sharp force/stress drop, the fracture zone of glass fiber above the carbon layers presents an inverted trapezoid shape, while the fracture of glass fiber below the carbon layers exhibits an inverted triangular shape. With regards to the intralayer hybrid composites, the C/G hybrid ratio plays a dominating role in the bending failure which could be considered as the mixed failures of four structures. The bending failure of intralayer hybrid composites occurs in advance since carbon fiber are located in each layer; the failure process shows a multi-stage fluctuating decline, and the decline slows down as carbon fiber content increases, and the fracture sound release has the characteristics of a low intensity and high frequency for a long time. By contrast, as glass fiber content increases, the bending failure of intralayer composites is featured with a multi-stage cliff decline with a high amplitude and low frequency for a short-time fracture sound release.

  16. Multiple Observation Types Jointly Constrain Terrestrial Carbon and Water Cycles

    Science.gov (United States)

    Raupach, M. R.; Haverd, V.; Briggs, P. R.; Canadell, J.; Davis, S. J.; Isaac, P. R.; Law, R.; Meyer, M.; Peters, G. P.; Pickett Heaps, C.; Roxburgh, S. H.; Sherman, B.; van Gorsel, E.; Viscarra Rossel, R.; Wang, Z.

    2012-12-01

    Information about the carbon cycle potentially constrains the water cycle, and vice versa. This paper explores the utility of multiple observation sets to constrain carbon and water fluxes and stores in a land surface model, and a resulting determination of the Australian terrestrial carbon budget. Observations include streamflow from 416 gauged catchments, measurements of evapotranspiration (ET) and net ecosystem production (NEP) from 12 eddy-flux sites, litterfall data, and data on carbon pools. The model is a version of CABLE (the Community Atmosphere-Biosphere-Land Exchange model), coupled with CASAcnp (a biogeochemical model) and SLI (Soil-Litter-Iso, a soil hydrology model including liquid and vapour water fluxes and the effects of litter). By projecting observation-prediction residuals onto model uncertainty, we find that eddy flux measurements provide a significantly tighter constraint on Australian continental net primary production (NPP) than the other data types. However, simultaneous constraint by multiple data types is important for mitigating bias from any single type. Results emerging from the multiply-constrained model are as follows (with all values applying over 1990-2011 and all ranges denoting ±1 standard error): (1) on the Australian continent, a predominantly semi-arid region, over half (0.64±0.05) of the water loss through ET occurs through soil evaporation and bypasses plants entirely; (2) mean Australian NPP is 2200±400 TgC/y, making the NPP/precipitation ratio about the same for Australia as the global land average; (3) annually cyclic ("grassy") vegetation and persistent ("woody") vegetation respectively account for 0.56±0.14 and 0.43±0.14 of NPP across Australia; (4) the average interannual variability of Australia's NEP (±180 TgC/y) is larger than Australia's total anthropogenic greenhouse gas emissions in 2011 (149 TgCeq/y), and is dominated by variability in desert and savannah regions. The mean carbon budget over 1990

  17. A Hybrid Method for the Modelling and Optimisation of Constrained Search Problems

    Directory of Open Access Journals (Sweden)

    Sitek Pawel

    2014-08-01

    Full Text Available The paper presents a concept and the outline of the implementation of a hybrid approach to modelling and solving constrained problems. Two environments of mathematical programming (in particular, integer programming and declarative programming (in particular, constraint logic programming were integrated. The strengths of integer programming and constraint logic programming, in which constraints are treated in a different way and different methods are implemented, were combined to use the strengths of both. The hybrid method is not worse than either of its components used independently. The proposed approach is particularly important for the decision models with an objective function and many discrete decision variables added up in multiple constraints. To validate the proposed approach, two illustrative examples are presented and solved. The first example is the authors’ original model of cost optimisation in the supply chain with multimodal transportation. The second one is the two-echelon variant of the well-known capacitated vehicle routing problem.

  18. Joint Optimal Production Planning for Complex Supply Chains Constrained by Carbon Emission Abatement Policies

    OpenAIRE

    He, Longfei; Xu, Zhaoguang; Niu, Zhanwen

    2014-01-01

    We focus on the joint production planning of complex supply chains facing stochastic demands and being constrained by carbon emission reduction policies. We pick two typical carbon emission reduction policies to research how emission regulation influences the profit and carbon footprint of a typical supply chain. We use the input-output model to capture the interrelated demand link between an arbitrary pair of two nodes in scenarios without or with carbon emission constraints. We design optim...

  19. Carbon nanotube-TiO(2) hybrid films for detecting traces of O(2).

    Science.gov (United States)

    Llobet, E; Espinosa, E H; Sotter, E; Ionescu, R; Vilanova, X; Torres, J; Felten, A; Pireaux, J J; Ke, X; Van Tendeloo, G; Renaux, F; Paint, Y; Hecq, M; Bittencourt, C

    2008-09-17

    Hybrid titania films have been prepared using an adapted sol-gel method for obtaining well-dispersed hydrogen plasma-treated multiwall carbon nanotubes in either pure titania or Nb-doped titania. The drop-coating method has been used to fabricate resistive oxygen sensors based on titania or on titania and carbon nanotube hybrids. Morphology and composition studies have revealed that the dispersion of low amounts of carbon nanotubes within the titania matrix does not significantly alter its crystallization behaviour. The gas sensitivity studies performed on the different samples have shown that the hybrid layers based on titania and carbon nanotubes possess an unprecedented responsiveness towards oxygen (i.e. more than four times higher than that shown by optimized Nb-doped TiO(2) films). Furthermore, hybrid sensors containing carbon nanotubes respond at significantly lower operating temperatures than their non-hybrid counterparts. These new hybrid sensors show a strong potential for monitoring traces of oxygen (i.e. ≤10 ppm) in a flow of CO(2), which is of interest for the beverage industry.

  20. Carbon nanotube-TiO2 hybrid films for detecting traces of O2

    International Nuclear Information System (INIS)

    Llobet, E; Espinosa, E H; Sotter, E; Ionescu, R; Vilanova, X; Torres, J; Felten, A; Pireaux, J J; Ke, X; Tendeloo, G Van; Renaux, F; Paint, Y; Hecq, M; Bittencourt, C

    2008-01-01

    Hybrid titania films have been prepared using an adapted sol-gel method for obtaining well-dispersed hydrogen plasma-treated multiwall carbon nanotubes in either pure titania or Nb-doped titania. The drop-coating method has been used to fabricate resistive oxygen sensors based on titania or on titania and carbon nanotube hybrids. Morphology and composition studies have revealed that the dispersion of low amounts of carbon nanotubes within the titania matrix does not significantly alter its crystallization behaviour. The gas sensitivity studies performed on the different samples have shown that the hybrid layers based on titania and carbon nanotubes possess an unprecedented responsiveness towards oxygen (i.e. more than four times higher than that shown by optimized Nb-doped TiO 2 films). Furthermore, hybrid sensors containing carbon nanotubes respond at significantly lower operating temperatures than their non-hybrid counterparts. These new hybrid sensors show a strong potential for monitoring traces of oxygen (i.e. ≤10 ppm) in a flow of CO 2 , which is of interest for the beverage industry

  1. Hybrid-type long-lived carbon stripper foils

    International Nuclear Information System (INIS)

    Sugai, Isao; Kato, Hajime

    1989-01-01

    A new method for the preparation of hybrid-type long-lived carbon stripper foils was developed. The new procedure is based on a modification of our controlled dc arc-discharge method. The carbon foils are of the multilayer type and the layers are composed of carbon particles emitted from the electrodes in the ac arc-discharge and from the cathode in the dc arc-discharge. With this simple and powerful method long lived carbon stripper foils can be prepared with higher reliability and reproducibility than with the previous procedure. (orig.)

  2. A Hybrid Course Design: The Best of Both Educational Worlds

    Science.gov (United States)

    Poirier, Sandra

    2010-01-01

    Career and technical educators are constantly being challenged to have their courses meet the changing needs of their students in this fast-paced world people live in. As the name implies, the hybrid online course is a melding of traditional and online learning. In this article, the author describes her experience designing hybrid courses that…

  3. Hybrid carbon nanomaterials for electrochemical detection of biomolecules

    International Nuclear Information System (INIS)

    Laurila, Tomi

    2015-01-01

    Electrochemical detection of different biomolecules in vivo is a promising path towards in situ monitoring of human body and its functions. However, there are several major obstacles, such as sensitivity, selectivity and biocompatiblity, which must be tackled in order to achieve reliably and safely operating sensor devices. Here we show that by utilizing hybrid carbon materials as electrodes to detect two types of neurotransmitters, dopamine and glutamate, several advantages over commonly used electrode materials can be achieved. In particular, we will demonstrate here that it is possible to combine the properties of different carbon allotropes to obtain hybrid materials with greatly improved electrochemical performance. Three following examples of the approach are given: (i) diamond-like carbon (DLC) thin film electrodes with different layer thicknesses, (ii) multi-walled carbon nanotubes grown directly on top of DLC and (iii) carbon nanofibres synthesized on top of DLC thin films. Detailed structural and electrochemical characterization is carried out to rationalize the reasons behind the observed behvior. In addition, results from the atomistic simulations are utilized to obtain more information about the properties of the amorphous carbon thin films. (paper)

  4. Organic-inorganic hybrid carbon dots for cell imaging

    Science.gov (United States)

    Liu, Huan; Zhang, Hongwen; Li, Jiayu; Tang, Yuying; Cao, Yu; Jiang, Yan

    2018-04-01

    In this paper, nitrogen-doped carbon dots (CDs) had been synthesized directly by one-step ultrasonic treatment under mild conditions. During the functionalization process, Octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt (OA-POSS) was used as stabilizing and passivation agent, which lead to self-assembling of CDs in aqueous medium solution. OA-POSS was obtained via hydrolytic condensation of γ-aminopropyl triethoxy silane (APTES). The average size of CDs prepared was approximately 3.3 nm with distribution between 2.5 nm and 4.5 nm. The prepared organic-inorganic hybrid carbon dots have several characteristics such as photoluminescence emission wavelength, efficient cellular uptake, and good biocompatibility. The results indicate that OA-POSS can maintain the fluorescence properties of the carbon dots effectively, and reduced cytotoxicity provides the possibility for biomedical applications. More than 89% of the Hela cells were viable when incubated with 2 mg ml‑1 or lesser organic-inorganic hybrid carbon dots. Thus, it provides a potential for multicolor imaging with HeLa cells.

  5. A hybrid energy-economy model for global integrated assessment of climate change, carbon mitigation and energy transformation

    International Nuclear Information System (INIS)

    Cai, Yiyong; Newth, David; Finnigan, John; Gunasekera, Don

    2015-01-01

    Highlights: • This paper introduces the design of a hybrid energy-economy model, GTEM-C. • The model offers a unified tool to analyse the energy-carbon-environment nexus. • Results are presented on global energy transformation due to carbon mitigation. • Electrification with renewable energies can contain the spiking of carbon prices. - Abstract: This paper introduces the design of the CSIRO variant of the Global Trade and Environment model (GTEM-C). GTEM-C is a hybrid model that combines the top-down macroeconomic representation of a computable general equilibrium model with the bottom-up engineering details of energy production. The model features detailed accounting for global energy flows that are embedded in traded energy goods, and it offers a unified framework to analyse the energy-carbon-environment nexus. As an illustrative example, we present simulation results on global energy transformation under the Intergovernmental Panel on Climate Change’s representative carbon pathways 4.5 and 8.5. By testing the model’s sensitivity to the relevant parameter, we find that the pace of electrification will significantly contain the spiking of carbon prices because electricity can be produced from carbon-free or less carbon-intensive technologies. The decoupling of energy use and carbon footprint, due to the uptake of clean electricity technologies, such as nuclear, wind, solar, and carbon capture and storage, allows the world to maintain high level of energy consumption, which is essential to economic growth

  6. Bio-inspired Hybrid Carbon Nanotube Muscles

    Science.gov (United States)

    Kim, Tae Hyeob; Kwon, Cheong Hoon; Lee, Changsun; An, Jieun; Phuong, Tam Thi Thanh; Park, Sun Hwa; Lima, Márcio D.; Baughman, Ray H.; Kang, Tong Mook; Kim, Seon Jeong

    2016-05-01

    There has been continuous progress in the development for biomedical engineering systems of hybrid muscle generated by combining skeletal muscle and artificial structure. The main factor affecting the actuation performance of hybrid muscle relies on the compatibility between living cells and their muscle scaffolds during cell culture. Here, we developed a hybrid muscle powered by C2C12 skeletal muscle cells based on the functionalized multi-walled carbon nanotubes (MWCNT) sheets coated with poly(3,4-ethylenedioxythiophene) (PEDOT) to achieve biomimetic actuation. This hydrophilic hybrid muscle is physically durable in solution and responds to electric field stimulation with flexible movement. Furthermore, the biomimetic actuation when controlled by electric field stimulation results in movement similar to that of the hornworm by patterned cell culture method. The contraction and relaxation behavior of the PEDOT/MWCNT-based hybrid muscle is similar to that of the single myotube movement, but has faster relaxation kinetics because of the shape-maintenance properties of the freestanding PEDOT/MWCNT sheets in solution. Our development provides the potential possibility for substantial innovation in the next generation of cell-based biohybrid microsystems.

  7. The World Banks' BioCarbon Fund

    Energy Technology Data Exchange (ETDEWEB)

    Noble, I.

    2003-03-01

    In November 2002 the World Bank launched the BioCarbon Fund, a public/private initiative to provide finance to projects that store carbon in vegetation and soils ('sinks') while helping to reverse land degradation, conserve biodiversity and improve the livelihoods of local communities. The Fund will seek projects to sequester or conserve carbon in non-Annex I countries and in countries in transition. Sinks may be the only option for poor nations with small energy to benefit from the carbon finance business. The Fund will include a portion of assets based on reductions in emissions such as substitution of biofuels for fossil fuels. The author Ian Noble of the World Bank, is chairman of the BioCarbon Fund Technical Advisory Committee.

  8. Low carbon development. Key issues

    Energy Technology Data Exchange (ETDEWEB)

    Urban, Frauke; Nordensvaard, Johan (eds.)

    2013-03-07

    This comprehensive textbook addresses the interface between international development and climate change in a carbon constrained world. It discusses the key conceptual, empirical and policy-related issues of low carbon development and takes an international and interdisciplinary approach to the subject by drawing on insights from across the natural sciences and social sciences whilst embedding the discussion in a global context. The first part explores the concept of low carbon development and explains the need for low carbon development in a carbon constrained world. The book then discusses the key issues of socio-economic, political and technological nature for low carbon development, exploring topics such as the political economy, social justice, financing and carbon markets, and technologies and innovation for low carbon development. This is followed by key issues for low carbon development in policy and practice, which is presented based on cross-cutting issues such as low carbon energy, forestry, agriculture and transportation. Afterwards, practical case studies are discussed from low carbon development in low income countries in Africa, middle income countries in Asia and Latin America and high income countries in Europe and North America.

  9. A hybrid guided neighborhood search for the disjunctively constrained knapsack problem

    Directory of Open Access Journals (Sweden)

    Mhand Hifi

    2015-12-01

    Full Text Available In this paper, we investigate the use of a hybrid guided neighborhood search for solving the disjunctively constrained knapsack problem. The studied problem may be viewed as a combination of two NP-hard combinatorial optimization problems: the weighted-independent set and the classical binary knapsack. The proposed algorithm is a hybrid approach that combines both deterministic and random local searches. The deterministic local search is based on a descent method, where both building and exploring procedures are alternatively used for improving the solution at hand. In order to escape from a local optima, a random local search strategy is introduced which is based on a modified ant colony optimization system. During the search process, the ant colony optimization system tries to diversify and to enhance the solutions using some informations collected from the previous iterations. Finally, the proposed algorithm is computationally analyzed on a set of benchmark instances available in the literature. The provided results are compared to those realized by both the Cplex solver and a recent algorithm of the literature. The computational part shows that the obtained results improve most existing solution values.

  10. Fatigue of hybrid glass/carbon composites: 3D computational studies

    DEFF Research Database (Denmark)

    Dai, Gaoming; Mishnaevsky, Leon

    2014-01-01

    3D computational simulations of fatigue of hybrid carbon/glass fiber reinforced composites is carried out using X-FEM and multifiber unit cell models. A new software code for the automatic generation of unit cell multifiber models of composites with randomly misaligned fibers of various properties...... and geometrical parameters is developed. With the use of this program code and the X-FEM method, systematic investigations of the effect of microstructure of hybrid composites (fraction of carbon versus glass fibers, misalignment, and interface strength) and the loading conditions (tensile versus compression...... cyclic loading effects) on fatigue behavior of the materials are carried out. It was demonstrated that the higher fraction of carbon fibers in hybrid composites is beneficial for the fatigue lifetime of the composites under tension-tension cyclic loading, but might have negative effect on the lifetime...

  11. Application of Crunch-Flow Routines to Constrain Present and Past Carbon Fluxes at Gas-Hydrate Bearing Sites

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Marta [Oregon State Univ., Corvallis, OR (United States). College of Earth, Ocean, and Atmospheric Sciences

    2014-01-31

    In November 2012, Oregon State University initiated the project entitled: Application of Crunch-Flow routines to constrain present and past carbon fluxes at gas-hydrate bearing sites. Within this project we developed Crunch-Flow based modeling modules that include important biogeochemical processes that need to be considered in gas hydrate environments. Our modules were applied to quantify carbon cycling in present and past systems, using data collected during several DOE-supported drilling expeditions, which include the Cascadia margin in US, Ulleung Basin in South Korea, and several sites drilled offshore India on the Bay of Bengal and Andaman Sea. Specifically, we completed modeling efforts that: 1) Reproduce the compositional and isotopic profiles observed at the eight drilled sites in the Ulleung Basin that constrain and contrast the carbon cycling pathways at chimney (high methane flux) and non-chimney sites (low methane, advective systems); 2) Simulate the Ba record in the sediments to quantify the past dynamics of methane flux in the southern Hydrate Ridge, Cascadia margin; and 3) Provide quantitative estimates of the thickness of individual mass transport deposits (MTDs), time elapsed after the MTD event, rate of sulfate reduction in the MTD, and time required to reach a new steady state at several sites drilled in the Krishna-Godavari (K-G) Basin off India. In addition we developed a hybrid model scheme by coupling a home-made MATLAB code with CrunchFlow to address the methane transport and chloride enrichment at the Ulleung Basins chimney sites, and contributed the modeling component to a study focusing on pore-scale controls on gas hydrate distribution in sediments from the Andaman Sea. These efforts resulted in two manuscripts currently under review, and contributed the modeling component of another pare, also under review. Lessons learned from these efforts are the basis of a mini-workshop to be held at Oregon State University (Feb 2014) to instruct

  12. Multiple Observation Types Jointly Constrain Australian Terrestrial Carbon and Water Cycles

    Science.gov (United States)

    Haverd, Vanessa; Raupach, Michael; Briggs, Peter; Canadell, Pep; Davis, Steven; Isaac, Peter; Law, Rachel; Meyer, Mick; Peters, Glenn; Pickett-Heaps, Christopher; Roxburgh, Stephen; Sherman, Bradford; van Gorsel, Eva; Viscarra Rossel, Raphael; Wang, Ziyuan

    2013-04-01

    Information about the carbon cycle potentially constrains the water cycle, and vice versa. This paper explores the utility of multiple observation sets to constrain carbon and water fluxes and stores in a land surface model, and a resulting determination of the Australian terrestrial carbon budget. Observations include streamflow from 416 gauged catchments, measurements of evapotranspiration (ET) and net ecosystem production (NEP) from 12 eddy-flux sites, litterfall data, and data on carbon pools. The model is a version of CABLE (the Community Atmosphere-Biosphere-Land Exchange model), coupled with CASAcnp (a biogeochemical model) and SLI (Soil-Litter-Iso, a soil hydrology model including liquid and vapour water fluxes and the effects of litter). By projecting observation-prediction residuals onto model uncertainty, we find that eddy flux measurements provide a significantly tighter constraint on Australian continental net primary production (NPP) than the other data types. However, simultaneous constraint by multiple data types is important for mitigating bias from any single type. Results emerging from the multiply-constrained model are as follows (with all values applying over 1990-2011 and all ranges denoting ±1 standard error): (1) on the Australian continent, a predominantly semi-arid region, over half (0.64±0.05) of the water loss through ET occurs through soil evaporation and bypasses plants entirely; (2) mean Australian NPP is 2200±400 TgC/y, making the NPP/precipitation ratio about the same for Australia as the global land average; (3) annually cyclic ("grassy") vegetation and persistent ("woody") vegetation respectively account for 0.56±0.14 and 0.43±0.14 of NPP across Australia; (4) the average interannual variability of Australia's NEP (±180 TgC/y) is larger than Australia's total anthropogenic greenhouse gas emissions in 2011 (149 TgCeq/y), and is dominated by variability in desert and savannah regions. The mean carbon budget over 1990

  13. 3D hybrid carbon composed of multigraphene bridged by carbon chains

    Directory of Open Access Journals (Sweden)

    Lingyu Liu

    2018-01-01

    Full Text Available The element carbon possesses various stable and metastable allotropes; some of them have been applied in diverse fields. The experimental evidences of both carbon chain and graphdiyne have been reported. Here, we reveal the mystery of an enchanting carbon allotrope with sp-, sp2-, and sp3-hybridized carbon atoms using a newly developed ab initio particle-swarm optimization algorithm for crystal structure prediction. This crystalline allotrope, namely m-C12, can be viewed as braided mesh architecture interwoven with multigraphene and carbon chains. The m-C12 meets the criteria for dynamic and mechanical stabilities and is energetically more stable than carbyne and graphdiyne. Analysis of the B/G and Poisson’s ratio indicates that this allotrope is ductile. Notably, m-C12 is a superconducting carbon with Tc of 1.13 K, which is rare in the family of carbon allotropes.

  14. Carbon nanotube reinforced hybrid composites: Computational modeling of environmental fatigue and usability for wind blades

    DEFF Research Database (Denmark)

    Dai, Gaoming; Mishnaevsky, Leon

    2015-01-01

    The potential of advanced carbon/glass hybrid reinforced composites with secondary carbon nanotube reinforcement for wind energy applications is investigated here with the use of computational experiments. Fatigue behavior of hybrid as well as glass and carbon fiber reinforced composites...... with the secondary CNT reinforcements (especially, aligned tubes) present superior fatigue performances than those without reinforcements, also under combined environmental and cyclic mechanical loading. This effect is stronger for carbon composites, than for hybrid and glass composites....

  15. Fe3O4/carbon hybrid nanoparticle electrodes for high-capacity electrochemical capacitors.

    Science.gov (United States)

    Lee, Jun Seop; Shin, Dong Hoon; Jun, Jaemoon; Lee, Choonghyeon; Jang, Jyongsik

    2014-06-01

    Fe3O4/carbon hybrid nanoparticles (FeCHNPs) were fabricated using dual-nozzle electrospraying, vapor deposition polymerization (VDP), and carbonization. FeOOH nanoneedles decorated with polypyrrole (PPy) nanoparticles (FePNPs) were fabricated by electrospraying pristine PPy mixed with FeCl3 solution, followed by heating stirring reaction. A PPy coating was then formed on the FeOOH nanoneedles through a VDP process. FeCHNPs were produced through carbonization of PPy and FeOOH phase transitions. These hybrid carbon nanoparticles (NPs) were used to build electrodes of electrochemical capacitors. The specific capacitance of the FeCHNPs was 455 F g(-1), which is larger than that of pristine PPy NPs (105 F g(-1)) or other hybrid PPy NPs. Furthermore, the FeCHNP-based capacitors exhibited better cycle stability during charge-discharge cycling than other hybrid NP capacitors. This is because the carbon layer on the Fe3 O4 surface formed a protective coating, preventing damage to the electrode materials during the charge-discharge processes. This fabrication technique is an effective approach for forming stable carbon/metal oxide nanostructures for energy storage applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Carbon nanotube-TiO{sub 2} hybrid films for detecting traces of O{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Llobet, E; Espinosa, E H; Sotter, E; Ionescu, R; Vilanova, X [MINOS, EMaS, Universitat Rovira i Virgili, 43007 Tarragona (Spain); Torres, J [Research Department, Carburos Metalicos, MATGAS, Campus UAB, 08193 Cerdanyola del Valles (Spain); Felten, A; Pireaux, J J [LISE, University of Namur, B-5000 Namur (Belgium); Ke, X; Tendeloo, G Van [EMAT, University of Antwerp, B-2020 Antwerp (Belgium); Renaux, F; Paint, Y; Hecq, M; Bittencourt, C [LCIA, University of Mons-Hainaut, B-7000, Mons (Belgium)

    2008-09-17

    Hybrid titania films have been prepared using an adapted sol-gel method for obtaining well-dispersed hydrogen plasma-treated multiwall carbon nanotubes in either pure titania or Nb-doped titania. The drop-coating method has been used to fabricate resistive oxygen sensors based on titania or on titania and carbon nanotube hybrids. Morphology and composition studies have revealed that the dispersion of low amounts of carbon nanotubes within the titania matrix does not significantly alter its crystallization behaviour. The gas sensitivity studies performed on the different samples have shown that the hybrid layers based on titania and carbon nanotubes possess an unprecedented responsiveness towards oxygen (i.e. more than four times higher than that shown by optimized Nb-doped TiO{sub 2} films). Furthermore, hybrid sensors containing carbon nanotubes respond at significantly lower operating temperatures than their non-hybrid counterparts. These new hybrid sensors show a strong potential for monitoring traces of oxygen (i.e. {<=}10 ppm) in a flow of CO{sub 2}, which is of interest for the beverage industry.

  17. Fabrication of Carbon Nanotube/SiO2and Carbon Nanotube/SiO2/Ag Nanoparticles Hybrids by Using Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Li Haiqing

    2009-01-01

    Full Text Available Abstract Based on plasma-treated single wall carbon nanotubes (SWCNTs, SWCNT/SiO2and thiol groups-functionalized SWCNT/SiO2hybrids have been fabricated through a sol–gel process. By means of thiol groups, Ag nanoparticles have been in situ synthesized and bonded onto the SiO2shell of SWCNT/SiO2in the absence of external reducing agent, resulting in the stable carbon nanotube/SiO2/Ag nanoparticles hybrids. This strategy provides a facile, low–cost, and green methodology for the creation of carbon nanotube/inorganic oxides-metal nanoparticles hybrids.

  18. Free-standing carbon nanotube/graphene hybrid papers as next generation adsorbents.

    Science.gov (United States)

    Dichiara, Anthony B; Sherwood, Tyler J; Benton-Smith, Jared; Wilson, Jonathan C; Weinstein, Steven J; Rogers, Reginald E

    2014-06-21

    The adsorption of a series of aromatic compounds from aqueous solution onto purified, free-standing single-walled carbon nanotube/graphene nanoplatelet hybrid papers is studied both experimentally and theoretically. Experimental data is obtained via changes in optical absorption spectra of the aqueous solutions and is used to extract all parameters required to implement a semi-empirical mass-transfer model. Agreement between experiment and theory is excellent and data from all compounds can be cast on a universal adsorption curve. Results indicate that the rate of adsorption and long-time capacity of many aromatic compounds on hybrid paper adsorbent significantly exceeds that of activated carbon by at least an order of magnitude. The combination of carbon nanotubes and graphene also promotes on the order of a 25% improvement in adsorption rates and capacities than either component alone. Hybrid nanocomposites show significant promise as adsorption materials used for environmental remediation efforts.

  19. Synthesis of MnO nano-particle@Flourine doped carbon and its application in hybrid supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Deyu; Feng, Xiaoke [Department of Chemistry, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, Hubei (China); Wei, Xi [School of Materials Science and Engineering, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, Hubei (China); Guo, Liping [Department of Chemistry, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, Hubei (China); Cai, Haopeng, E-mail: cai_haopeng@whut.edu.cn [School of Materials Science and Engineering, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, Hubei (China); Tang, Haolin [School of Materials Science and Engineering, State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, Hubei (China); Xie, Zhizhong, E-mail: zhizhong_xie@163.com [Department of Chemistry, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, Hubei (China)

    2017-08-15

    Highlights: • A Fluorine doped carbon encapsulated MnO nanoparticle material was fabricated through a self-assembly method. • Nafion ionomers was used as the fluorine and carbon precursor. • A lithium ion supercapacitor was assemblied by using MnO@FC and porous carbon. • A stable energy density as well as superior cycling stability were demonstrated in this hybrid system. - Abstract: A flourine doped carbon materials encapsulated MnO nano-particle was synthesized through a self-assembly method. The MnO nano-crystal covered with a thin layer of graphite were achieved. This hybrid MnO/carbon materials were employed as negative electrode in a new lithium ion hybrid supercapacitor, while the electrochemical double-layer porous carbon served as positive electrode. The electrochemical performances of this hybrid device were investigated and exhibited relative high capacity upto 40 mAh g{sup −1} in an applied current of 200 mAh g{sup −1}, good rate performance as well as superior cycling stability.

  20. Carbon Redox-Polymer-Gel Hybrid Supercapacitors

    Science.gov (United States)

    Vlad, A.; Singh, N.; Melinte, S.; Gohy, J.-F.; Ajayan, P.M.

    2016-01-01

    Energy storage devices that provide high specific power without compromising on specific energy are highly desirable for many electric-powered applications. Here, we demonstrate that polymer organic radical gel materials support fast bulk-redox charge storage, commensurate to surface double layer ion exchange at carbon electrodes. When integrated with a carbon-based electrical double layer capacitor, nearly ideal electrode properties such as high electrical and ionic conductivity, fast bulk redox and surface charge storage as well as excellent cycling stability are attained. Such hybrid carbon redox-polymer-gel electrodes support unprecedented discharge rate of 1,000C with 50% of the nominal capacity delivered in less than 2 seconds. Devices made with such electrodes hold the potential for battery-scale energy storage while attaining supercapacitor-like power performances. PMID:26917470

  1. Lifecycle cost assessment and carbon dioxide emissions of diesel, natural gas, hybrid electric, fuel cell hybrid and electric transit buses

    International Nuclear Information System (INIS)

    Lajunen, Antti; Lipman, Timothy

    2016-01-01

    This paper evaluates the lifecycle costs and carbon dioxide emissions of different types of city buses. The simulation models of the different powertrains were developed in the Autonomie vehicle simulation software. The carbon dioxide emissions were calculated both for the bus operation and for the fuel and energy pathways from well to tank. Two different operating environment case scenarios were used for the primary energy sources, which were Finland and California (USA). The fuel and energy pathways were selected appropriately in relation to the operating environment. The lifecycle costs take into account the purchase, operating, maintenance, and possible carbon emission costs. Based on the simulation results, the energy efficiency of city buses can be significantly improved by the alternative powertrain technologies. Hybrid buses have moderately lower carbon dioxide emissions during the service life than diesel buses whereas fully-electric buses have potential to significantly reduce carbon dioxide emissions, by up to 75%. The lifecycle cost analysis indicates that diesel hybrid buses are already competitive with diesel and natural gas buses. The high costs of fuel cell and battery systems are the major challenges for the fuel cell hybrid buses in order to reduce lifecycle costs to more competitive levels. - Highlights: • Alternative powertrains can significantly improve energy efficiency of transit buses. • Operating environment has an important impact on the lifecycle costs of buses. • Diesel hybrid buses are already cost effective solution for public transportation. • The cost of fuel cell technology is the major challenge for fuel cell hybrid buses. • Fully-electric buses have potential to significantly reduce carbon dioxide emissions.

  2. Functional Carbon Nanotube/Mesoporous Carbon/MnO2 Hybrid Network for High-Performance Supercapacitors

    Directory of Open Access Journals (Sweden)

    Tao Tao

    2014-01-01

    Full Text Available A functional carbon nanotube/mesoporous carbon/MnO2 hybrid network has been developed successfully through a facile route. The resulting composites exhibited a high specific capacitance of 351 F/g at 1 A g−1, with intriguing charge/discharge rate performance and cycling stability due to a synergistic combination of large surface area and excellent electron-transport capabilities of MnO2 with the good conductivity of the carbon nanotube/mesoporous carbon networks. Such composite shows great potential to be used as electrodes for supercapacitors.

  3. Superhard sp2–sp3 hybrid carbon allotropes with tunable electronic properties

    Directory of Open Access Journals (Sweden)

    Meng Hu

    2016-05-01

    Full Text Available Four sp2–sp3 hybrid carbon allotropes are proposed on the basis of first principles calculations. These four carbon allotropes are energetically more favorable than graphite under suitable pressure conditions. They can be assembled from graphite through intralayer wrinkling and interlayer buckling, which is similar to the formation of diamond from graphite. For one of the sp2–sp3 hybrid carbon allotropes, mC24, the electron diffraction patterns match these of i-carbon, which is synthesized from shock-compressed graphite (H. Hirai and K. Kondo, Science, 1991, 253, 772. The allotropes exhibit tunable electronic characteristics from metallic to semiconductive with band gaps comparable to those of silicon allotropes. They are all superhard materials with Vickers hardness values comparable to that of cubic BN. The sp2–sp3 hybrid carbon allotroes are promising materials for photovoltaic electronic devices, and abrasive and grinding tools.

  4. MIROS: a hybrid real-time energy-efficient operating system for the resource-constrained wireless sensor nodes.

    Science.gov (United States)

    Liu, Xing; Hou, Kun Mean; de Vaulx, Christophe; Shi, Hongling; El Gholami, Khalid

    2014-09-22

    Operating system (OS) technology is significant for the proliferation of the wireless sensor network (WSN). With an outstanding OS; the constrained WSN resources (processor; memory and energy) can be utilized efficiently. Moreover; the user application development can be served soundly. In this article; a new hybrid; real-time; memory-efficient; energy-efficient; user-friendly and fault-tolerant WSN OS MIROS is designed and implemented. MIROS implements the hybrid scheduler and the dynamic memory allocator. Real-time scheduling can thus be achieved with low memory consumption. In addition; it implements a mid-layer software EMIDE (Efficient Mid-layer Software for User-Friendly Application Development Environment) to decouple the WSN application from the low-level system. The application programming process can consequently be simplified and the application reprogramming performance improved. Moreover; it combines both the software and the multi-core hardware techniques to conserve the energy resources; improve the node reliability; as well as achieve a new debugging method. To evaluate the performance of MIROS; it is compared with the other WSN OSes (TinyOS; Contiki; SOS; openWSN and mantisOS) from different OS concerns. The final evaluation results prove that MIROS is suitable to be used even on the tight resource-constrained WSN nodes. It can support the real-time WSN applications. Furthermore; it is energy efficient; user friendly and fault tolerant.

  5. MIROS: A Hybrid Real-Time Energy-Efficient Operating System for the Resource-Constrained Wireless Sensor Nodes

    Science.gov (United States)

    Liu, Xing; Hou, Kun Mean; de Vaulx, Christophe; Shi, Hongling; Gholami, Khalid El

    2014-01-01

    Operating system (OS) technology is significant for the proliferation of the wireless sensor network (WSN). With an outstanding OS; the constrained WSN resources (processor; memory and energy) can be utilized efficiently. Moreover; the user application development can be served soundly. In this article; a new hybrid; real-time; memory-efficient; energy-efficient; user-friendly and fault-tolerant WSN OS MIROS is designed and implemented. MIROS implements the hybrid scheduler and the dynamic memory allocator. Real-time scheduling can thus be achieved with low memory consumption. In addition; it implements a mid-layer software EMIDE (Efficient Mid-layer Software for User-Friendly Application Development Environment) to decouple the WSN application from the low-level system. The application programming process can consequently be simplified and the application reprogramming performance improved. Moreover; it combines both the software and the multi-core hardware techniques to conserve the energy resources; improve the node reliability; as well as achieve a new debugging method. To evaluate the performance of MIROS; it is compared with the other WSN OSes (TinyOS; Contiki; SOS; openWSN and mantisOS) from different OS concerns. The final evaluation results prove that MIROS is suitable to be used even on the tight resource-constrained WSN nodes. It can support the real-time WSN applications. Furthermore; it is energy efficient; user friendly and fault tolerant. PMID:25248069

  6. Water-assisted growth of graphene-carbon nanotube hybrids in plasma

    Science.gov (United States)

    Tewari, Aarti; Ghosh, Santanu; Srivastava, Pankaj

    2018-04-01

    The enhanced growth of graphene-carbon nanotube (CNT) hybrids in a hydrocarbon and hydrogen plasma assisted by water is numerically formulated. The catalyst activity and agglomeration of catalyst particles are the rate determining factors in the growth of hybrids and their constituents, i.e., the CNT and graphene. The water vapor concentration is varied to investigate its effect on the growth process. The enhanced catalyst activity on account of oxidation by hydroxyl ions of water to impede the agglomeration of catalyst particles and the removal of amorphous carbon through etching by hydrogen ions of water are seen to be the main driving forces behind the many fold increase in the dimensions of constituent nanostructures and the hybrids with water vapor concentration. Importantly, beyond a certain specific water vapor concentration, the growth rates dropped due to active oxidation of the catalyst particle.

  7. Scenarios for transition towards a low-carbon world in 2050: what's at stake for heavy industries? Joint Research Project 'Carbon-constrained scenarios'. Results and final report

    International Nuclear Information System (INIS)

    2008-11-01

    The EpE-IDDRI study, Launched in 2004, explores how major industrial sectors will be impacted by a carbon constraint stabilizing atmospheric CO 2 concentration at 450 ppm. By means of an innovative hybrid modelling platform and ongoing dialogue between researchers and industrials, the study produces conclusions concerning both general climate policy as well as the economic response of industrial sectors- specifically of the steel, aluminium, cement, and sheet glass sectors, as well as of the energy sector

  8. Hierarchically porous carbon/polyaniline hybrid for use in supercapacitors.

    Science.gov (United States)

    Joo, Min Jae; Yun, Young Soo; Jin, Hyoung-Joon

    2014-12-01

    A hierarchically porous carbon (HPC)/polyaniline (PANI) hybrid electrode was prepared by the polymerization of PANI on the surface of the HPC via rapid-mixing polymerization. The surface morphologies and chemical composition of the HPC/PANI hybrid electrode were characterized using transmission electron microscopy and X-ray photoelectron spectroscopy (XPS), respectively. The surface morphologies and XPS results for the HPC, PANI and HPC/PANI hybrids indicate that PANI is coated on the surface of HPC in the HPC/PANI hybrids which have two different nitrogen groups as a benzenoid amine (-NH-) peak and positively charged nitrogen (N+) peak. The electrochemical performances of the HPC/PANI hybrids were analyzed by performing cyclic voltammetry and galvanostatic charge-discharge tests. The HPC/PANI hybrids showed a better specific capacitance (222 F/g) than HPC (111 F/g) because of effect of pseudocapacitor behavior. In addition, good cycle stabilities were maintained over 1000 cycles.

  9. Graphene quantum dots-carbon nanotube hybrid arrays for supercapacitors

    Science.gov (United States)

    Hu, Yue; Zhao, Yang; Lu, Gewu; Chen, Nan; Zhang, Zhipan; Li, Hui; Shao, Huibo; Qu, Liangti

    2013-05-01

    Graphene quantum dots (GQDs) have been successfully deposited onto aligned carbon nanotubes (CNTs) by a benign electrochemical method and the capacitive properties of the as-formed GQD/CNT hybrid arrays were evaluated in symmetrical supercapacitors. It was found that supercapacitors fabricated from GQD/CNT hybrid arrays exhibited a high capacitance of 44 mF cm-2, representing a more than 200% improvement over that of bare CNT electrodes.

  10. Hybrid carbon/glass fiber composites: Micromechanical analysis of structure–damage resistance relationships

    DEFF Research Database (Denmark)

    Mishnaevsky, Leon; Dai, Gaoming

    2014-01-01

    A computational study of the effect of microstructure of hybrid carbon/glass fiber composites on their strength is presented. Unit cells with hundreds of randomly located and misaligned fibers of various properties and arrangements are subject to tensile and compression loading, and the evolution...... strength than pure composites, while the strength of hybrid composites under inform force loading increases steadily with increasing the volume content of carbon fibers....... of fiber damages is analyzed in numerical experiments. The effects of fiber clustering, matrix properties, nanoreinforcement, load sharing rules on the strength and damage resistance of composites are studied. It was observed that hybrid composites under uniform displacement loading might have lower...

  11. Stochastic resonance in small-world neuronal networks with hybrid electrical–chemical synapses

    International Nuclear Information System (INIS)

    Wang, Jiang; Guo, Xinmeng; Yu, Haitao; Liu, Chen; Deng, Bin; Wei, Xile; Chen, Yingyuan

    2014-01-01

    Highlights: •We study stochastic resonance in small-world neural networks with hybrid synapses. •The resonance effect depends largely on the probability of chemical synapse. •An optimal chemical synapse probability exists to evoke network resonance. •Network topology affects the stochastic resonance in hybrid neuronal networks. - Abstract: The dependence of stochastic resonance in small-world neuronal networks with hybrid electrical–chemical synapses on the probability of chemical synapse and the rewiring probability is investigated. A subthreshold periodic signal is imposed on one single neuron within the neuronal network as a pacemaker. It is shown that, irrespective of the probability of chemical synapse, there exists a moderate intensity of external noise optimizing the response of neuronal networks to the pacemaker. Moreover, the effect of pacemaker driven stochastic resonance of the system depends largely on the probability of chemical synapse. A high probability of chemical synapse will need lower noise intensity to evoke the phenomenon of stochastic resonance in the networked neuronal systems. In addition, for fixed noise intensity, there is an optimal chemical synapse probability, which can promote the propagation of the localized subthreshold pacemaker across neural networks. And the optimal chemical synapses probability turns even larger as the coupling strength decreases. Furthermore, the small-world topology has a significant impact on the stochastic resonance in hybrid neuronal networks. It is found that increasing the rewiring probability can always enhance the stochastic resonance until it approaches the random network limit

  12. Fusion-fission hybrids: environmental aspects and their role in hybrid rationale

    International Nuclear Information System (INIS)

    Holdren, J.P.

    1981-01-01

    The rationale for developing hybrids depends on real or perceived liabilities of relying on pure fission to do the same job. Quite possibly the main constraint on expanded use of fission will be neither lack of fuel nor high costs, but perceived environmental liabilities - radioactive wastes, reactor safety, and links to nuclear weaponry. The environmental characteristics of hybrid systems and pure-fisson systems are compared here in detail. The findings are that significant environmental advantages for hybrids cannot now be demonstrated and may not exist. Therefore, if environmental drawbacks constrain the application of pure fission, hybrids probably also will be thus constrained

  13. Hierarchical porous carbon/MnO2 hybrids as supercapacitor electrodes.

    Science.gov (United States)

    Lee, Min Eui; Yun, Young Soo; Jin, Hyoung-Joon

    2014-12-01

    Hybrid electrodes of hierarchical porous carbon (HPC) and manganese oxide (MnO2) were synthesized using a fast surface redox reaction of potassium permanganate under facile immersion methods. The HPC/MnO2 hybrids had a number of micropores and macropores and the MnO2 nanoparticles acted as a pseudocapacitive material. The synergistic effects of electric double-layer capacitor (EDLC)-induced capacitance and pseudocapacitance brought about a better electrochemical performance of the HPC/MnO2 hybrid electrodes compared to that obtained with a single component. The hybrids showed a specific capacitance of 228 F g(-1) and good cycle stability over 1000 cycles.

  14. Cathode-supported hybrid direct carbon fuel cells

    DEFF Research Database (Denmark)

    Gil, Vanesa; Gurauskis, Jonas; Deleebeeck, Lisa

    2017-01-01

    The direct conversion of coal to heat and electricity by a hybrid direct carbon fuel cell (HDCFC) is a highly efficient and cleaner technology than the conventional combustion power plants. HDCFC is defined as a combination of solid oxide fuel cell and molten carbonate fuel cell. This work...... investigates cathode-supported cells as an alternative configuration for HDCFC, with better catalytic activity and performance. This study aims to define the best processing route to manufacture highly efficient cathode-supported cells based on La0.75Sr0.25MnO3/yttria-stabilized zirconia infiltrated backbones...

  15. Electron field emission characteristics of graphene/carbon nanotubes hybrid field emitter

    International Nuclear Information System (INIS)

    Chen, Leifeng; He, Hong; Yu, Hua; Cao, Yiqi; Lei, Da; Menggen, QiQiGe; Wu, Chaoxing; Hu, Liqin

    2014-01-01

    The graphene (GP) and multi-walled carbon nanotubes (MCNTs) hybrid nanostructure emitter was constructed by a larger scale electrophoretic deposition (EPD) method. The field emission (FE) performance of the hybrid emitter is greatly improved compared with that of only GP or MCNTs emitter. The low turn-on electric field (EF), the low threshold EF and the reliability FE properties are obtained from the hybrid emitter. The better FE properties result from the improved electrical properties. For further enhancement FE of hybrids, Ag Nanoparticles (NPs) were decorated on the hybrids and FE characteristics were also studied. These studies indicate that we can use the hybrid nanostructure to improve conductivity and contact resistance, which results in enhancement of the FE properties

  16. Natural Gas, Wind and Nuclear Options for Generating Electricity in a Carbon Constrained World

    NARCIS (Netherlands)

    Kooten, van G.C.

    2012-01-01

    A linear programming model is used to examine the impact of carbon taxes on the optimal generation mix in the Alberta electrical system. The model permits decommissioning of generating assets with high carbon dioxide emissions and investment in new gas-fired, wind and, in some scenarios, nuclear

  17. Hybrid Effect Evaluation of Steel Fiber and Carbon Fiber on the Performance of the Fiber Reinforced Concrete.

    Science.gov (United States)

    Song, Weimin; Yin, Jian

    2016-08-18

    Fiber reinforcement is an important method to enhance the performance of concrete. In this study, the compressive test and impact test were conducted, and then the hybrid effect between steel fiber (SF) and carbon fiber (CF) was evaluated by employing the hybrid effect index. Compressive toughness and impact toughness of steel fiber reinforced concrete (SFRC), carbon fiber reinforced concrete (CFRC) and hybrid fiber reinforced concrete (HFRC) were explored at steel fiber volume fraction 0.5%, 1%, 1.5% and carbon fiber 0.1%, 0.2%, 0.3%. Results showed that the addition of steel fiber and carbon fiber can increase the compressive strength. SF, CF and the hybridization between them could increase the compressive toughness significantly. The impact test results showed that as the volume of fiber increased, the impact number of the first visible crack and the ultimate failure also increased. The improvement of toughness mainly lay in improving the crack resistance after the first crack. Based on the test results, the positive hybrid effect of steel fiber and carbon fiber existed in hybrid fiber reinforced concrete. The relationship between the compressive toughness and impact toughness was also explored.

  18. Hybrid Carbon-Glass Fiber/Toughened Epoxy Thick Composite Joints Subject to Drop-Weight and Ballistic Impacts

    National Research Council Canada - National Science Library

    Liaw, Benjamin; Delale, Feridun

    2007-01-01

    ... No. DAAD19-02-R-0010 to conduct research on hybrid carbon-S2 glass fiber/toughened epoxy thick-section, hybrid interwoven composite joints subject to drop-weight and ballistic impacts. Dr. Basavaraju B. Raju of U.S...

  19. Carbon Nanotubes Hybrid Hydrogels in Drug Delivery: A Perspective Review

    Science.gov (United States)

    Hampel, Silke; Spizzirri, Umile Gianfranco; Parisi, Ortensia Ilaria; Picci, Nevio; Iemma, Francesca

    2014-01-01

    The use of biologics, polymers, silicon materials, carbon materials, and metals has been proposed for the preparation of innovative drug delivery devices. One of the most promising materials in this field are the carbon-nanotubes composites and hybrid materials coupling the advantages of polymers (biocompatibility and biodegradability) with those of carbon nanotubes (cellular uptake, stability, electromagnatic, and magnetic behavior). The applicability of polymer-carbon nanotubes composites in drug delivery, with particular attention to the controlled release by composites hydrogel, is being extensively investigated in the present review. PMID:24587993

  20. Scheduling Appliances with GA, TLBO, FA, OSR and Their Hybrids Using Chance Constrained Optimization for Smart Homes

    Directory of Open Access Journals (Sweden)

    Zunaira Nadeem

    2018-04-01

    Full Text Available In this paper, we design a controller for home energy management based on following meta-heuristic algorithms: teaching learning-based optimization (TLBO, genetic algorithm (GA, firefly algorithm (FA and optimal stopping rule (OSR theory. The principal goal of designing this controller is to reduce the energy consumption of residential sectors while reducing consumer’s electricity bill and maximizing user comfort. Additionally, we propose three hybrid schemes OSR-GA, OSR-TLBO and OSR-FA, by combining the best features of existing algorithms. We have also optimized the desired parameters: peak to average ratio, energy consumption, cost, and user comfort (appliance waiting time for 20, 50, 100 and 200 heterogeneous homes in two steps. In the first step, we obtain the optimal scheduling of home appliances implementing our aforementioned hybrid schemes for single and multiple homes while considering user preferences and threshold base policy. In the second step, we formulate our problem through chance constrained optimization. Simulation results show that proposed hybrid scheduling schemes outperformed for single and multiple homes and they shift the consumer load demand exceeding a predefined threshold to the hours where the electricity price is low thus following the threshold base policy. This helps to reduce electricity cost while considering the comfort of a user by minimizing delay and peak to average ratio. In addition, chance-constrained optimization is used to ensure the scheduling of appliances while considering the uncertainties of a load hence smoothing the load curtailment. The major focus is to keep the appliances power consumption within the power constraint, while keeping power consumption below a pre-defined acceptable level. Moreover, the feasible regions of appliances electricity consumption are calculated which show the relationship between cost and energy consumption and cost and waiting time.

  1. Ultrafast cooling by covalently bonded graphene-carbon nanotube hybrid immersed in water

    DEFF Research Database (Denmark)

    Chen, Jie; Walther, Jens Honore; Koumoutsakos, Petros

    2016-01-01

    , we demonstrate, through transient heat-dissipation simulations, that a covalently bonded graphene-carbon nanotube (G-CNT) hybrid immersed in water is a promising solution for the ultrafast cooling of such high-temperature and high heat-flux surfaces. The G-CNT hybrid offers a unique platform...

  2. Hybrid carbon nanostructure assemblage for high performance pseudo-capacitors

    Directory of Open Access Journals (Sweden)

    A. K. Mishra

    2012-06-01

    Full Text Available Investigation of novel nanocomposites for pseudo-capacitors with high capacitance and energy density is the spotlight of current energy research. In the present work, hybrid carbon nanostructure assemblage of graphene and multiwalled carbon nanotubes has been used as carbon support to nanostructured RuO2 and polyaniline for high energy supercapacitors. Maximum specific capacitances of 110, 235 and 440 F g−1 at the voltage sweep rate of 10 mV s−1 and maximum energy densities of 7, 12.5 and 20.5 Wh kg−1 were observed for carbon assemblage and its RuO2 and polyanilne decorated nanocomposites, respectively, with 1M H2SO4 as electrolyte.

  3. Superhard sp{sup 2}–sp{sup 3} hybrid carbon allotropes with tunable electronic properties

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Meng; Ma, Mengdong; Zhao, Zhisheng; Yu, Dongli; He, Julong, E-mail: hjl@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2016-05-15

    Four sp{sup 2}–sp{sup 3} hybrid carbon allotropes are proposed on the basis of first principles calculations. These four carbon allotropes are energetically more favorable than graphite under suitable pressure conditions. They can be assembled from graphite through intralayer wrinkling and interlayer buckling, which is similar to the formation of diamond from graphite. For one of the sp{sup 2}–sp{sup 3} hybrid carbon allotropes, mC24, the electron diffraction patterns match these of i-carbon, which is synthesized from shock-compressed graphite (H. Hirai and K. Kondo, Science, 1991, 253, 772). The allotropes exhibit tunable electronic characteristics from metallic to semiconductive with band gaps comparable to those of silicon allotropes. They are all superhard materials with Vickers hardness values comparable to that of cubic BN. The sp{sup 2}–sp{sup 3} hybrid carbon allotroes are promising materials for photovoltaic electronic devices, and abrasive and grinding tools.

  4. Tensile properties of a boron/nitrogen-doped carbon nanotube–graphene hybrid structure

    Directory of Open Access Journals (Sweden)

    Kang Xia

    2014-03-01

    Full Text Available Doping is an effective approach that allows for the intrinsic modification of the electrical and chemical properties of nanomaterials. Recently, a graphene and carbon nanotube hybrid structure (GNHS has been reported, which extends the excellent properties of carbon-based materials to three dimensions. In this paper, we carried out a first-time investigation on the tensile properties of the hybrid structures with different dopants. It is found that with the presence of dopants, the hybrid structures usually exhibit lower yield strength, Young’s modulus, and earlier yielding compared to that of a pristine hybrid structure. For dopant concentrations below 2.5% no significant reduction of Young’s modulus or yield strength could be observed. For all considered samples, the failure is found to initiate at the region where the nanotubes and graphene sheets are connected. After failure, monatomic chains are normally observed around the failure region. Dangling graphene layers without the separation of a residual CNT wall are found to adhere to each other after failure with a distance of about 3.4 Å. This study provides a fundamental understanding of the tensile properties of the doped graphene–nanotube hybrid structures, which will benefit the design and also the applications of graphene-based hybrid materials.

  5. Panorama of explicit carbon pricing instruments around the world

    International Nuclear Information System (INIS)

    2016-09-01

    In September 2016, I4CE updated its database on carbon pricing policies and published a panorama of explicit carbon pricing policies. This panorama presents an implementation timeline, a world map and a table that together, provide information on the jurisdictions that have implemented or plan to implement explicit carbon pricing policies, the type of instrument chosen, the sectors covered and the carbon prices

  6. Toronto hybrid taxi pilot

    International Nuclear Information System (INIS)

    Stevens, M.; Marans, B.

    2009-10-01

    This paper provided details of a hybrid taxi pilot program conducted to compare the on-road performance of Toyota Camry hybrid vehicles against conventional vehicles over a 1-year period in order to determine the business case and air emission reductions associated with the use of hybrid taxi cabs. Over 750,000 km worth of fuel consumption was captured from 10 Toyota Camry hybrids, a Toyota Prius, and 5 non-hybrid Camry vehicles over an 18-month period. The average real world fuel consumption for the taxis demonstrated that the Toyota Prius has the lowest cost of ownership, while the non-hybrid Camry has the highest cost of ownership. Carbon dioxide (CO 2 ) reductions associated with the 10 Camry hybrid taxis were calculated at 236 tonnes over a 7-year taxi service life. Results suggested that the conversion of Toronto's 5680 taxis would yield annual CO 2 emission reductions of over 19,000 tonnes. All hybrid purchasers identified themselves as highly likely to purchase a hybrid again. 5 tabs., 9 figs.

  7. Toronto hybrid taxi pilot

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, M. [CrossChasm Technologies, Cambridge, ON (Canada); Marans, B. [Toronto Atmospheric Fund, ON (Canada)

    2009-10-15

    This paper provided details of a hybrid taxi pilot program conducted to compare the on-road performance of Toyota Camry hybrid vehicles against conventional vehicles over a 1-year period in order to determine the business case and air emission reductions associated with the use of hybrid taxi cabs. Over 750,000 km worth of fuel consumption was captured from 10 Toyota Camry hybrids, a Toyota Prius, and 5 non-hybrid Camry vehicles over an 18-month period. The average real world fuel consumption for the taxis demonstrated that the Toyota Prius has the lowest cost of ownership, while the non-hybrid Camry has the highest cost of ownership. Carbon dioxide (CO{sub 2}) reductions associated with the 10 Camry hybrid taxis were calculated at 236 tonnes over a 7-year taxi service life. Results suggested that the conversion of Toronto's 5680 taxis would yield annual CO{sub 2} emission reductions of over 19,000 tonnes. All hybrid purchasers identified themselves as highly likely to purchase a hybrid again. 5 tabs., 9 figs.

  8. Tribological properties of three-dimensional braided carbon/Kevlar/epoxy hybrid composites under dry and lubricated conditions

    International Nuclear Information System (INIS)

    Wan, Y.Z.; Huang, Y.; He, F.; Li, Q.Y.; Lian, J.J.

    2007-01-01

    This paper presents a study of the tribological properties of three-dimensional (3-D) braided carbon/Kevlar/epoxy hybrid composites. Their specific wear rate and the coefficient of friction were examined as a function of operating conditions (load and sliding distance) under dry and lubricated conditions. In addition, the 3-D braided hybrid composites with varying carbon to Kevlar fiber volume ratio were tested to assess hybrid effects. It was found that the friction and wear rate decreased with sliding distance and then leveled off under dry and lubricated conditions. Different changing patterns with normal load were observed under two different sliding conditions. Furthermore, it was noted that negative hybrid effects on the wear resistance and the friction coefficient were identified for the current 3-D braided hybrid system. The composite with a carbon to Kevlar ratio of 3:2 was found to have the least wear and friction among all 3-D braided hybrid composites studied. Worn surfaces were observed by scanning electron microscope (SEM) and wear mechanisms were discussed in this study

  9. Tetrapropylammonium ion influence on the synthesis of Pt Ru/carbon hybrids by hydrothermal carbonization

    International Nuclear Information System (INIS)

    Tusi, M.M.; Polanco, N.S.O.; Brandalise, M.; Correa, O.V.; Silva, A.C.; Oliveira Neto, A.; Linardi, M.; Spinace, E.V.

    2010-01-01

    PtRu/Carbon hybrid materials were prepared by hydrothermal carbonization using starch as carbon source and reducing agent and H 2 PtCl 6 .6H 2 O e RuCl 3 .xH 2 O as metals source and catalyst of the carbonization process. The materials were prepared in the following conditions: without pH adjustment, in the absence and in the presence of tetrapropylammonium chloride (TPACl), and adjusting the pH using potassium hydroxide (KOH) or tetrapropylammonium hydroxide (TPAOH). The obtained materials were treated under argon atmosphere at 900 deg C and characterized by SEM/EDX, BET isotherm, XRD and TEM. The electro-oxidation of methanol was studied by chronoamperometry. The material prepared using TPAOH showed the best performance for methanol electro-oxidation. (author)

  10. Growth of hybrid carbon nanostructures on iron-decorated ZnO nanorods

    Science.gov (United States)

    Mbuyisa, Puleng N.; Rigoni, Federica; Sangaletti, Luigi; Ponzoni, Stefano; Pagliara, Stefania; Goldoni, Andrea; Ndwandwe, Muzi; Cepek, Cinzia

    2016-04-01

    A novel carbon-based nanostructured material, which includes carbon nanotubes (CNTs), porous carbon, nanostructured ZnO and Fe nanoparticles, has been synthetized using catalytic chemical vapour deposition (CVD) of acetylene on vertically aligned ZnO nanorods (NRs). The deposition of Fe before the CVD process induces the presence of dense CNTs in addition to the variety of nanostructures already observed on the process done on the bare NRs, which range from amorphous graphitic carbon up to nanostructured dendritic carbon films, where the NRs are partially or completely etched. The combination of scanning electron microscopy and in situ photoemission spectroscopy indicate that Fe enhances the ZnO etching, and that the CNT synthesis is favoured by the reduced Fe mobility due to the strong interaction between Fe and the NRs, and to the presence of many defects, formed during the CVD process. Our results demonstrate that the resulting new hybrid shows a higher sensitivity to ammonia gas at ambient conditions (∼60 ppb) than the carbon nanostructures obtained without the aid of Fe, the bare ZnO NRs, or other one-dimensional carbon nanostructures, making this system of potential interest for environmental ammonia monitoring. Finally, in view of the possible application in nanoscale optoelectronics, the photoexcited carrier behaviour in these hybrid systems has been characterized by time-resolved reflectivity measurements.

  11. Carbon hybridized halloysite nanotubes for high-performance hydrogen storage capacities

    Science.gov (United States)

    Jin, Jiao; Fu, Liangjie; Yang, Huaming; Ouyang, Jing

    2015-01-01

    Hybrid nanotubes of carbon and halloysite nanotubes (HNTs) with different carbon:HNTs ratio were hydrothermally synthesized from natural halloysite and sucrose. The samples display uniformly cylindrical hollow tubular structure with different morphologies. These hybrid nanotubes were concluded to be promising medium for physisorption-based hydrogen storage. The hydrogen adsorption capacity of pristine HNTs was 0.35% at 2.65 MPa and 298 K, while that of carbon coated HNTs with the pre-set carbon:HNTs ratio of 3:1 (3C-HNTs) was 0.48% under the same condition. This carbon coated method could offer a new pattern for increasing the hydrogen adsorption capacity. It was also possible to enhance the hydrogen adsorption capacity through the spillover mechanism by incorporating palladium (Pd) in the samples of HNTs (Pd-HNTs) and 3C-HNTs (Pd-3C-HNTs and 3C-Pd-HNTs are the samples with different location of Pd nanoparticles). The hydrogen adsorption capacity of the Pd-HNTs was 0.50% at 2.65 MPa and 298 K, while those of Pd-3C-HNTs and 3C-Pd-HNTs were 0.58% and 0.63%, respectively. In particular, for this spillover mechanism of Pd-carbon-HNTs ternary system, the bidirectional transmission of atomic and molecular hydrogen (3C-Pd-HNTs) was concluded to be more effective than the unidirectional transmission (Pd-3C-HNTs) in this work for the first time. PMID:26201827

  12. Zero- and two-dimensional hybrid carbon phosphors for high colorimetric purity white light-emission.

    Science.gov (United States)

    Ding, Yamei; Chang, Qing; Xiu, Fei; Chen, Yingying; Liu, Zhengdong; Ban, Chaoyi; Cheng, Shuai; Liu, Juqing; Huang, Wei

    2018-03-01

    Carbon nanomaterials are promising phosphors for white light emission. A facile single-step synthesis method has been developed to prepare zero- and two-dimensional hybrid carbon phosphors for the first time. Zero-dimensional carbon dots (C-dots) emit bright blue luminescence under 365 nm UV light and two-dimensional nanoplates improve the dispersity and film forming ability of C-dots. As a proof-of-concept application, the as-prepared hybrid carbon phosphors emit bright white luminescence in the solid state, and the phosphor-coated blue LEDs exhibit high colorimetric purity white light-emission with a color coordinate of (0.3308, 0.3312), potentially enabling the successful application of white emitting phosphors in the LED field.

  13. World-Economy Centrality and Carbon Dioxide Emissions: A New Look at the Position in the Capitalist World-System and Environmental Pollution

    Directory of Open Access Journals (Sweden)

    Paul Prew

    2015-08-01

    Full Text Available With the ever-growing concern of climate change, much attention has been paid to the factors driving carbon dioxide emissions. Previous research in the World-Systems perspective has identified a relationship between carbon dioxide emissions and position in the world-economy. This study intends to build on the previous research by developing a new, more parsimonious indicator of World-System position based on Immanuel Wallerstein’s theoretical concepts of incorporation and core-periphery processes. The new World-System indicator is derived from the centrality measure in network analysis based on import data from the International Monetary Fund’s Direction of Trade Statistics. Based on the theoretical concepts of core-periphery processes, carbon dioxide emissions are predicted to rise based on the predominance of energy-intensive, high-technology, core processes within the nation. The results tend to demonstrate a strong relationship between carbon dioxide emissions and position in the world-economy, and the new World-System position indicator is more strongly related with carbon dioxide emissions than Gross Domestic Product per capita.

  14. MOF-Derived ZnO Nanoparticles Covered by N-Doped Carbon Layers and Hybridized on Carbon Nanotubes for Lithium-Ion Battery Anodes.

    Science.gov (United States)

    Zhang, Hui; Wang, Yunsong; Zhao, Wenqi; Zou, Mingchu; Chen, Yijun; Yang, Liusi; Xu, Lu; Wu, Huaisheng; Cao, Anyuan

    2017-11-01

    Metal-organic frameworks (MOFs) have many promising applications in energy and environmental areas such as gas separation, catalysis, supercapacitors, and batteries; the key toward those applications is controlled pyrolysis which can tailor the porous structure, improve electrical conductivity, and expose metal ions in MOFs. Here, we present a systematic study on the structural evolution of zeolitic imidazolate frameworks hybridized on carbon nanotubes (CNTs) during the carbonization process. We show that a number of typical products can be obtained, depending on the annealing time, including (1) CNTs wrapped by relatively thick carbon layers, (2) CNTs grafted by ZnO nanoparticles which are covered by thin nitrogen-doped carbon layers, and (3) CNTs grafted by aggregated ZnO nanoparticles. We also investigated the electrochemical properties of those hybrid structures as freestanding membrane electrodes for lithium ion batteries, and the second one (CNT-supported ZnO covered by N-doped carbon) shows the best performance with a high specific capacity (850 mA h/g at a current density of 100 mA/g) and excellent cycling stability. Our results indicate that tailoring and optimizing the MOF-CNT hybrid structure is essential for developing high-performance energy storage systems.

  15. Effect of Carbon Coating on Li4TiO12 of Anode Material for Hybrid Capacitor.

    Science.gov (United States)

    Lee, Jong-Kyu; Lee, Byung-Gwan; Yoon, Jung-Rag

    2015-11-01

    The carbon-coated Li4Ti5O12 of anode material for hybrid capacitor was prepared by controlling carbonization time at 700 degrees C in nitrogen. With increasing of carbonization time, the discharge capacity and capacitance were decreased, while the equivalent series resistance was not changed remarkably. The rate capability and cycle performance of carbon-coated Li4Ti5O12 were larger than that of Li4Ti5O12. Carbon coating improved conductivity as well as Li-ion diffusion, and thus also resulted in good rate capabilities and cycle stability. The effects of carbon coating on the gas generation of hybrid capacitor were also discussed.

  16. Complementarity of flux- and biometric-based data to constrain parameters in a terrestrial carbon model

    Directory of Open Access Journals (Sweden)

    Zhenggang Du

    2015-03-01

    Full Text Available To improve models for accurate projections, data assimilation, an emerging statistical approach to combine models with data, have recently been developed to probe initial conditions, parameters, data content, response functions and model uncertainties. Quantifying how many information contents are contained in different data streams is essential to predict future states of ecosystems and the climate. This study uses a data assimilation approach to examine the information contents contained in flux- and biometric-based data to constrain parameters in a terrestrial carbon (C model, which includes canopy photosynthesis and vegetation–soil C transfer submodels. Three assimilation experiments were constructed with either net ecosystem exchange (NEE data only or biometric data only [including foliage and woody biomass, litterfall, soil organic C (SOC and soil respiration], or both NEE and biometric data to constrain model parameters by a probabilistic inversion application. The results showed that NEE data mainly constrained parameters associated with gross primary production (GPP and ecosystem respiration (RE but were almost invalid for C transfer coefficients, while biometric data were more effective in constraining C transfer coefficients than other parameters. NEE and biometric data constrained about 26% (6 and 30% (7 of a total of 23 parameters, respectively, but their combined application constrained about 61% (14 of all parameters. The complementarity of NEE and biometric data was obvious in constraining most of parameters. The poor constraint by only NEE or biometric data was probably attributable to either the lack of long-term C dynamic data or errors from measurements. Overall, our results suggest that flux- and biometric-based data, containing different processes in ecosystem C dynamics, have different capacities to constrain parameters related to photosynthesis and C transfer coefficients, respectively. Multiple data sources could also

  17. 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

  18. A hybrid method for provincial scale energy-related carbon emission allocation in China.

    Science.gov (United States)

    Bai, Hongtao; Zhang, Yingxuan; Wang, Huizhi; Huang, Yanying; Xu, He

    2014-01-01

    Achievement of carbon emission reduction targets proposed by national governments relies on provincial/state allocations. In this study, a hybrid method for provincial energy-related carbon emissions allocation in China was developed to provide a good balance between production- and consumption-based approaches. In this method, provincial energy-related carbon emissions are decomposed into direct emissions of local activities other than thermal power generation and indirect emissions as a result of electricity consumption. Based on the carbon reduction efficiency principle, the responsibility for embodied emissions of provincial product transactions is assigned entirely to the production area. The responsibility for carbon generation during the production of thermal power is borne by the electricity consumption area, which ensures that different regions with resource endowments have rational development space. Empirical studies were conducted to examine the hybrid method and three indices, per capita GDP, resource endowment index and the proportion of energy-intensive industries, were screened to preliminarily interpret the differences among China's regional carbon emissions. Uncertainty analysis and a discussion of this method are also provided herein.

  19. Major oil exporters may profit rather than lose, in a carbon-constrained world

    International Nuclear Information System (INIS)

    Persson, Tobias A.; Azar, C.; Johansson, D.; Lindgren, K.

    2007-01-01

    The Organization of Petroleum Exporting Countries (OPEC) claims compensation for losses in expected oil export revenues due to CO 2 mitigation measures in developing countries. These losses are expected for two primary reasons: a reduction in the consumption of oil in importing countries and a reduction in the producer price of oil (taxation in an importing country implies a transfer of rents from producers to consumers). So far, most studies have focused on these two mechanisms and corroborated that revenue losses for OPEC are to be expected. However, there are also mechanisms that may be expected to raise the price of oil products. In a cost-effective regime for dealing with climate change, i.e., a regime in which all or most countries participate and in which the same carbon price is applied on all carbon-emitting activities, the cost of using unconventional oil, or synthetic diesel from coal, will increase even more than the cost of using conventional oil. Given that reserves of conventional oil are expected to dwindle over time, heavy oils and coal to liquids might set the long-run price for liquid fuels, which means that the price of oil would increase beyond the carbon fee; i.e., the rent on conventional oil would increase. We use an energy-economic optimization model to analyze these three mechanisms. We find that the net present value of OPEC revenue from conventional oil increases slightly (at most by 4 percent) with a global CO 2 restriction regime. We also consider conditions under which this result does not hold

  20. Design and control strategy for a hybrid green energy system for mobile telecommunication sites

    Science.gov (United States)

    Okundamiya, Michael S.; Emagbetere, Joy O.; Ogujor, Emmanuel A.

    2014-07-01

    The rising energy costs and carbon footprint of operating mobile telecommunication sites in the emerging world have increased research interests in green technology. The intermittent nature of most green energy sources creates the problem of designing the optimum configuration for a given location. This study presents the design analysis and control strategy for a cost effective and reliable operation of the hybrid green energy system (HGES) for GSM base transceiver station (BTS) sites in isolated regions. The design constrains the generation and distribution of power to reliably satisfy the energy demand while ensuring safe operation of the system. The overall process control applies the genetic algorithm-based technique for optimal techno-economic sizing of system's components. The process simulation utilized meteorological data for 3 locations (Abuja, Benin City and Sokoto) with varying climatic conditions in Nigeria. Simulation results presented for green GSM BTS sites are discussed and compared with existing approaches.

  1. Efficient photovoltaic conversion of graphene–carbon nanotube hybrid films grown from solid precursors

    International Nuclear Information System (INIS)

    Gan, Xin; Lv, Ruitao; Bai, Junfei; Zhang, Zexia; Wei, Jinquan; Huang, Zheng-Hong; Zhu, Hongwei; Kang, Feiyu; Terrones, Mauricio

    2015-01-01

    Large-area (e.g. centimeter size) graphene sheets are usually synthesized via pyrolysis of gaseous carbon precursors (e.g. methane) on metal substrates like Cu using chemical vapor deposition (CVD), but the presence of grain boundaries and the residual polymers during transfer deteriorates significantly the properties of the CVD graphene. If carbon nanotubes (CNTs) can be covalently bonded to graphene, the hybrid system could possess excellent electrical conductivity, transparency and mechanical strength. In this work, conducting and transparent CNT–graphene hybrid films were synthesized by a facile solid precursor pyrolysis method. Furthermore, the synthesized CNT–graphene hybrid films display enhanced photovoltaic conversion efficiency when compared to devices based on CNT membranes or graphene sheets. Upon chemical doping, the graphene–CNT/Si solar cells reveal power conversion efficiencies up to 8.50%. (paper)

  2. Graphene-Vertically Aligned Carbon Nanotube Hybrid on PDMS as Stretchable Electrodes.

    Science.gov (United States)

    Ding, Junjun; Fu, Shichen; Zhang, Runzhi; Boon, Eric Peter; Lee, Woo; Fisher, Frank T; Yang, Eui-Hyeok

    2017-09-11

    Stretchable electrodes are a critical component for flexible electronics such as displays, energy devices, and wearable sensors. Carbon nanotubes (CNTs) and graphene have been considered for flexible electrode applications, due to their mechanical strength, high carrier mobility, and excellent thermal conductivity. Vertically aligned carbon nanotubes (VACNTs) provide the possibility to serve as interconnects to graphene sheets as stretchable electrodes that could maintain high electrical conductivity under large tensile strain. In this work, a graphene oxide (GO) -VACNT hybrid on a PDMS substrate was demonstrated. Here, 50 μm long VACNTs were grown on a Si/SiO2 wafer substrate via atmospheric pressure chemical vapor deposition (APCVD). VACNTs were directly transferred by delamination from the Si/SiO2 to a semi-cured PDMS substrate, ensuring strong adhesion between VACNTs and PDMS upon full curing of the PDMS. GO ink was then printed on the surface of the VACNT carpet and thermally reduced to reduced graphene oxide (rGO). The sheet resistance of the rGO-VACNT hybrid was measured under uniaxial tensile strains up to 300% applied to the substrate. Under applied strain, the rGO-VACNT hybrid maintained a sheet resistant of 386±55 Ω/sq. Cyclic stretching of the rGO-VACNT hybrid was performed with up to 50 cycles at 100% maximum tensile strain, showing no increase in sheet resistance. These results demonstrate promising performance of the rGO-VACNT hybrid for flexible electronics applications. © 2017 IOP Publishing Ltd.

  3. Graphene—vertically aligned carbon nanotube hybrid on PDMS as stretchable electrodes

    Science.gov (United States)

    Ding, Junjun; Fu, Shichen; Zhang, Runzhi; Boon, Eric; Lee, Woo; Fisher, Frank T.; Yang, Eui-Hyeok

    2017-11-01

    Stretchable electrodes are a critical component for flexible electronics such as displays, energy devices, and wearable sensors. Carbon nanotubes (CNTs) and graphene have been considered for flexible electrode applications, due to their mechanical strength, high carrier mobility, and excellent thermal conductivity. Vertically aligned carbon nanotubes (VACNTs) provide the possibility to serve as interconnects to graphene sheets as stretchable electrodes that could maintain high electrical conductivity under large tensile strain. In this work, a graphene oxide (GO)-VACNT hybrid on a PDMS substrate was demonstrated. Here, 50 μm long VACNTs were grown on a Si/SiO2 wafer substrate via atmospheric pressure chemical vapor deposition. VACNTs were directly transferred by delamination from the Si/SiO2 to a semi-cured PDMS substrate, ensuring strong adhesion between VACNTs and PDMS upon full curing of the PDMS. GO ink was then printed on the surface of the VACNT carpet and thermally reduced to reduced graphene oxide (rGO). The sheet resistance of the rGO-VACNT hybrid was measured under uniaxial tensile strains up to 300% applied to the substrate. Under applied strain, the rGO-VACNT hybrid maintained a sheet resistant of 386 ± 55 Ω/sq. Cyclic stretching of the rGO-VACNT hybrid was performed with up to 50 cycles at 100% maximum tensile strain, showing no increase in sheet resistance. These results demonstrate promising performance of the rGO-VACNT hybrid for flexible electronics applications.

  4. 3D carbon fiber mats/nano-Fe3O4 hybrid material with high electromagnetic shielding performance

    Science.gov (United States)

    Zhan, Yingqing; Long, Zhihang; Wan, Xinyi; Zhang, Jiemin; He, Shuangjiang; He, Yi

    2018-06-01

    To obtain high-performance electromagnetic shielding materials, structure and morphology are two key factors. We here developed an efficient and facial method to prepare high-performance 3D carbon nanofiber mats (CFM)/Fe3O4 hybrid electromagnetic shielding materials. For this purpose, the CFM were chemically modified by mussel-inspired poly-dopamine coating, which were further used as templates for decoration of Fe3O4 nanoparticles via solvothermal route. It was found that the Fe3O4 nano-spheres with diameters of 200-250 nm were uniformly coated on the surface of 3D carbon nanofibers. More importantly, the morphology and structure of resulting 3D carbon nanofiber mats/Fe3O4 hybrids could be easily controlled by altering the experiment parameters, which were examined by FT-IR, XPS, TGA, XRD, SEM, and TEM. The measured magnetic properties showed that saturation magnetism and coercivity increased from 13.4 to 39.7 emu/g and 85.3 to 104.6 Oe, respectively. The lowest reflectivity of resulting hybrid was calculated to be -47 dB at 10.0 GHz (2.5 mm). In addition, the reflectivity of 3D carbon nanofiber mats/Fe3O4 hybrid was less than -25 dB in the range of 7-13 GHz. Moreover, the resulting 3D carbon nanofiber mats/Fe3O4 hybrid exhibited an EMI shielding performance of -62.6 dB in the frequency range of 8.2-12.4 GHz. Therefore, 3D carbon fiber mats/Fe3O4 hybrids can be ideal EMI materials with strong absorption, low density, and wide absorption range.

  5. Hybrid Direct Carbon Fuel Cell Performance with Anode Current Collector Material

    DEFF Research Database (Denmark)

    Deleebeeck, Lisa; Kammer Hansen, Kent

    2015-01-01

    collectors were studied: Au, Ni, Ag, and Pt. It was shown that the performance of the direct carbon fuel cell (DCFC) is dependent on the current collector materials, Ni and Pt giving the best performance, due to their catalytic activity. Gold is suggested to be the best material as an inert current collector......The influence of the current collector on the performance of a hybrid direct carbon fuel cell (HDCFC), consisting of solid oxide fuel cell (SOFC) with a molten carbonate-carbon slurry in contact with the anode, has been investigated using current-voltage curves. Four different anode current...

  6. Hybrid MnO2/carbon nanotube-VN/carbon nanotube supercapacitors

    Science.gov (United States)

    Su, Y.; Zhitomirsky, I.

    2014-12-01

    Composite materials, containing fibrous VN nanoparticles and multiwalled carbon nanotubes (MWCNT) are prepared by a chemical method for application in electrochemical supercapacitors. We demonstrate for the first time that VN-MWCNT electrodes exhibit good capacitive behavior in 0.5 M Na2SO4 electrolyte in a negative voltage window of 0.9 V. Quartz crystal microbalance studies provide an insight into the mechanism of charge storage. Composite VN-MWCNT materials show significant improvement in capacitance, compared to individual VN and MWCNT materials. Testing results indicate that VN-MWCNT electrodes exhibit high specific capacitance at high mass loadings in the range of 10-30 mg cm-2, good capacitance retention at scan rates in the range of 2-200 mV s-1 and good cycling stability. The highest specific capacitance of 160 F g-1 is achieved at a scan rate of 2 mV s-1. The new findings open a new and promising strategy in the fabrication of hybrid devices based on VN. The proof-of-principle is demonstrated by the fabrication of hybrid supercapacitor devices based on VN-MWCNT negative electrodes and MnO2 -MWCNT positive electrodes with voltage window of 1.8 V in aqueous 0.5 M Na2SO4 electrolyte. The hybrid VN-MWCNT/MnO2-MWCNT supercapacitor cells show promising capacitive and power-energy characteristics.

  7. Facile Synthesis of Coaxial CNTs/MnOx-Carbon Hybrid Nanofibers and Their Greatly Enhanced Lithium Storage Performance.

    Science.gov (United States)

    Yang, Zunxian; Lv, Jun; Pang, Haidong; Yan, Wenhuan; Qian, Kun; Guo, Tailiang; Guo, Zaiping

    2015-12-01

    Carbon nanotubes (CNTs)/MnOx-Carbon hybrid nanofibers have been successfully synthesized by the combination of a liquid chemical redox reaction (LCRR) and a subsequent carbonization heat treatment. The nanostructures exhibit a unique one-dimensional core/shell architecture, with one-dimensional CNTs encapsulated inside and a MnOx-carbon composite nanoparticle layer on the outside. The particular porous characteristics with many meso/micro holes/pores, the highly conductive one-dimensional CNT core, as well as the encapsulating carbon matrix on the outside of the MnOx nanoparticles, lead to excellent electrochemical performance of the electrode. The CNTs/MnOx-Carbon hybrid nanofibers exhibit a high initial reversible capacity of 762.9 mAhg(-1), a high reversible specific capacity of 560.5 mAhg(-1) after 100 cycles, and excellent cycling stability and rate capability, with specific capacity of 396.2 mAhg(-1) when cycled at the current density of 1000 mAg(-1), indicating that the CNTs/MnOx-Carbon hybrid nanofibers are a promising anode candidate for Li-ion batteries.

  8. Assimilation of repeated woody biomass observations constrains decadal ecosystem carbon cycle uncertainty in aggrading forests

    Science.gov (United States)

    Smallman, T. L.; Exbrayat, J.-F.; Mencuccini, M.; Bloom, A. A.; Williams, M.

    2017-03-01

    Forest carbon sink strengths are governed by plant growth, mineralization of dead organic matter, and disturbance. Across landscapes, remote sensing can provide information about aboveground states of forests and this information can be linked to models to estimate carbon cycling in forests close to steady state. For aggrading forests this approach is more challenging and has not been demonstrated. Here we apply a Bayesian approach, linking a simple model to a range of data, to evaluate their information content, for two aggrading forests. We compare high information content analyses using local observations with retrievals using progressively sparser remotely sensed information (repeated, single, and no woody biomass observations). The net biome productivity of both forests is constrained to be a net sink with litter dynamics at one forest, while at the second forest total dead organic matter estimates are within observational uncertainty. The uncertainty of retrieved ecosystem traits in the repeated biomass analysis is reduced by up to 50% compared to analyses with less biomass information. This study quantifies the importance of repeated woody observations in constraining the dynamics of both wood and dead organic matter, highlighting the benefit of proposed remote sensing missions.

  9. MnO-carbon hybrid nanofiber composites as superior anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wang, Jian-Gan; Yang, Ying; Huang, Zheng-Hong; Kang, Feiyu

    2015-01-01

    MnO-carbon hybrid nanofiber composites are fabricated by electrospinning polyimide/manganese acetylacetonate precursor and a subsequent carbonization process. The composition, phase structure and morphology of the composites are characterized by scanning and transmission electron microscopy, X-ray diffraction and thermogravimetric analysis. The results indicate that the composites exhibit good nanofibrous morphology with MnO nanoparticles uniformly encapsulated by carbon nanofibers. The hybrid nanofiber composites are used directly as freestanding anodes for lithium-ion batteries to evaluate their electrochemical properties. It is found that the optimized MnO-carbon nanofiber composite can deliver a high reversible capacity of 663 mAh g −1 , along with excellent cycling stability and good rate capability. The superior performance enables the composites to be promising candidates as an anode alternative for high-performance lithium-ion batteries

  10. Template-free electrochemical nanofabrication of polyaniline nanobrush and hybrid polyaniline with carbon nanohorns for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Wei Di; Andrew, Piers; Ryhaenen, Tapani [Nokia Research Centre Cambridge, Broers Building, 21 J J Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Wang, Haolan; Hiralal, Pritesh; Amaratunga, Gehan A J [Electrical Engineering Division, Department of Engineering, University of Cambridge, 9 J J Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Hayashi, Yasuhiko, E-mail: di.wei@nokia.com, E-mail: gaja1@cam.ac.uk [Department of Materials Science, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

    2010-10-29

    Polyaniline (PANI) nanobrushes were synthesized by template-free electrochemical galvanostatic methods. When the same method was applied to the carbon nanohorn (CNH) solution containing aniline monomers, a hybrid nanostructure containing PANI and CNHs was enabled after electropolymerization. This is the first report on the template-free method to make PANI nanobrushes and homogeneous hybrid soft matter (PANI) with carbon nanoparticles. Raman spectroscopy was used to analyze the interaction between CNH and PANI. Electrochemical nanofabrication offers simplicity and good control when used to make electronic devices. Both of these materials were applied in supercapacitors and an improvement capacitive current by using the hybrid material was observed.

  11. Template-free electrochemical nanofabrication of polyaniline nanobrush and hybrid polyaniline with carbon nanohorns for supercapacitors

    Science.gov (United States)

    Wei, Di; Wang, Haolan; Hiralal, Pritesh; Andrew, Piers; Ryhänen, Tapani; Hayashi, Yasuhiko; Amaratunga, Gehan A. J.

    2010-10-01

    Polyaniline (PANI) nanobrushes were synthesized by template-free electrochemical galvanostatic methods. When the same method was applied to the carbon nanohorn (CNH) solution containing aniline monomers, a hybrid nanostructure containing PANI and CNHs was enabled after electropolymerization. This is the first report on the template-free method to make PANI nanobrushes and homogeneous hybrid soft matter (PANI) with carbon nanoparticles. Raman spectroscopy was used to analyze the interaction between CNH and PANI. Electrochemical nanofabrication offers simplicity and good control when used to make electronic devices. Both of these materials were applied in supercapacitors and an improvement capacitive current by using the hybrid material was observed.

  12. Activated carbon/manganese dioxide hybrid electrodes for high performance thin film supercapacitors

    Science.gov (United States)

    Jang, Yunseok; Jo, Jeongdai; Jang, Hyunjung; Kim, Inyoung; Kang, Dongwoo; Kim, Kwang-Young

    2014-06-01

    We combine the activated carbon (AC) and the manganese dioxide (MnO2) in a AC/MnO2 hybrid electrode to overcome the low capacitance of activated carbon and MnO2 by exploiting the large surface area of AC and the fast reversible redox reaction of MnO2. An aqueous permanganate (MnO4 -) is converted to MnO2 on the surface of the AC electrode by dipping the AC electrode into an aqueous permanganate solution. The AC/MnO2 hybrid electrode is found to display superior specific capacitance of 290 F/g. This shows that supercapacitors classified as electric double layer capacitors and pseudocapacitors can be combined together.

  13. Synergistic increase of oxygen reduction favourable Fe-N coordination structures in a ternary hybrid of carbon nanospheres/carbon nanotubes/graphene sheets.

    Science.gov (United States)

    Zhang, Shiming; Liu, Bin; Chen, Shengli

    2013-11-14

    A Fe/N co-doped ternary nanocarbon hybrid, with uniform bamboo-like carbon nanotubes (CNTs) in situ grown on/between the single/few-layer graphene sheets interspaced by carbon nanosphere aggregates, was prepared through a one-pot heat treatment of a precursor mixture containing graphene oxide, Vulcan XC-72 carbon nanospheres, nitrogen rich melamine and small amounts of Fe ions. Physical characterization including electron microscopic images, N2 adsorption-desorption isotherms, pore size distribution, XPS, XRD, Mössbauer spectra, and EDX revealed that the 0-D/1-D/2-D ternary hybrid architecture not only offered an optimized morphology for high dispersion of each nanocarbon moiety, while the carbon nanosphere interspaced graphene sheets have provided a platform for efficient reaction between Fe ions and melamine molecules, resulting in uniform nucleation and growth of CNTs and formation of high density Fe-N coordination assemblies that have been believed to be the active centers for the oxygen reduction reaction (ORR) in carbon-based nonprecious metal electrocatalysts. In the absence of graphene oxides or carbon nanospheres, a similar heat treatment was found to result in large amounts of elemental Fe and Fe carbides and entangled CNTs with wide diameter distributions. As a result, the ternary Fe/N-doped nanocarbon hybrid exhibits ORR activity much higher than the Fe-N doped single or binary nanocarbon materials prepared under similar heat treatment conditions, and approaching that of the state-of-the-art carbon-supported platinum catalyst (Pt/C) in acidic media, as well as superior stability and methanol tolerance to Pt/C.

  14. Joint Optimal Production Planning for Complex Supply Chains Constrained by Carbon Emission Abatement Policies

    Directory of Open Access Journals (Sweden)

    Longfei He

    2014-01-01

    Full Text Available We focus on the joint production planning of complex supply chains facing stochastic demands and being constrained by carbon emission reduction policies. We pick two typical carbon emission reduction policies to research how emission regulation influences the profit and carbon footprint of a typical supply chain. We use the input-output model to capture the interrelated demand link between an arbitrary pair of two nodes in scenarios without or with carbon emission constraints. We design optimization algorithm to obtain joint optimal production quantities combination for maximizing overall profit under regulatory policies, respectively. Furthermore, numerical studies by featuring exponentially distributed demand compare systemwide performances in various scenarios. We build the “carbon emission elasticity of profit (CEEP” index as a metric to evaluate the impact of regulatory policies on both chainwide emissions and profit. Our results manifest that by facilitating the mandatory emission cap in proper installation within the network one can balance well effective emission reduction and associated acceptable profit loss. The outcome that CEEP index when implementing Carbon emission tax is elastic implies that the scale of profit loss is greater than that of emission reduction, which shows that this policy is less effective than mandatory cap from industry standpoint at least.

  15. Optical and mechanical excitation thermography for impact response in basalt-carbon hybrid fiber-reinforced composite laminates

    OpenAIRE

    Zhang, Hai; Sfarra, Stefano; Sarasini, Fabrizio; Ibarra-Castanedo, Clemente; Perilli, Stefano; Fernandes, Henrique; Duan, Yuxia; Peeters, Jeroen; Avelidis, Nicholas P; Maldague, Xavier

    2017-01-01

    Abstract: In this paper, optical and mechanical excitation thermography were used to investigate basalt fiber reinforced polymer (BFRP), carbon fiber reinforced polymer (CFRP) and basalt-carbon fiber hybrid specimens subjected to impact loading. Interestingly, two different hybrid structures including sandwich-like and intercalated stacking sequence were used. Pulsed phase thermography (PPT), principal component thermography (PCT) and partial least squares thermography (PLST) were used to pro...

  16. A study of nitroxide polyradical/activated carbon composite as the positive electrode material for electrochemical hybrid capacitor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hui-qiao; Zou, Ying; Xia, Yong-yao [Chemistry Department and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China)

    2007-01-01

    We present a new concept of the hybrid electrochemical capacitor technology in which a poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) nitroxide polyradical/activated carbon composite (PTMA-AC) is used as the positive electrode material and activated carbon is used as the negative electrode material. On the positive electrode, both reversible reduction and oxidation of nitroxide polyradical and non-faradic ion sorption/de-sorption of activated carbon are involved during charge and discharge process. The capacity of the composite electrode is 30% larger than that of the pure activated carbon electrode. A hybrid capacitor fabricated by the PTMA-AC composite positive electrode and the activated carbon negative electrode shows a good cycling life, it can be charged/discharged for over 1000 cycles with slight capacity loss. The hybrid capacitor also has a good rate capability, it maintains 80% of the initial capacity even at the high discharge current of up to 20C. (author)

  17. Exploring the Role of Plant Genetics to Enhance Soil Carbon Sequestration in Hybrid Poplar Plantations

    Science.gov (United States)

    Wullschleger, S. D.; Garten, C. T.; Classen, A. T.

    2008-12-01

    Atmospheric CO2 concentrations have increased in recent decades and are projected to increase even further during the coming century. These projections have prompted scientists and policy-makers to consider how plants and soils can be used to stabilize CO2 concentrations. Although storing carbon in terrestrial ecosystems represents an attractive near-term option for mitigating rising atmospheric CO2 concentrations, enhancing the sequestration potential of managed systems will require advancements in understanding the fundamental mechanisms that control rates of carbon transfer and turnover in plants and soils. To address this challenge, a mathematical model was constructed to evaluate how changes in particular plant traits and management practices could affect soil carbon storage beneath hybrid poplar (Populus) plantations. The model was built from four sub-models that describe aboveground biomass, root biomass, soil carbon dynamics, and soil nitrogen transformations for trees growing throughout a user-defined rotation. Simulations could be run over one or multiple rotations. A sensitivity analysis of the model indicated changes in soil carbon storage were affected by variables that could be linked to hybrid poplar traits like rates of aboveground production, partitioning of carbon to coarse and fine roots, and rates of root decomposition. A higher ratio of belowground to aboveground production was especially important and correlated directly with increased soil carbon storage. Faster decomposition rates for coarse and fine dead roots resulted in a greater loss of carbon to the atmosphere as CO2 and less residual organic carbon for transfer to the fast soil carbon pool. Hence, changes in root chemistry that prolonged dead root decomposition rates, a trait that is under potential genetic control, were predicted to increase soil carbon storage via higher soil carbon inputs. Nitrogen limitation of both aboveground biomass production and soil carbon sequestration was

  18. A sp2+sp3 hybridized carbon allotrope transformed from AB stacking graphyne and THD-graphene

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2018-01-01

    Full Text Available New carbon allotropes can be designed by combining sp, sp2 and sp3 three hybridization states. And the hybridization states or coordination numbers of carbon atoms can be changed by applying high pressure on carbon materials. In this study, a common high pressure phase (named as TBBC transformed from AB-stacking graphyne or THD-graphene is predicted. Its kinetic stability is examined using finite displacement method. We find that the sp2 and sp3 hybridized carbon atoms behave different vibration features at high frequency region. Both graphene-like and diamond-like vibration peaks occurs. Phase transition energy barriers from both graphyne and THD-graphene to TBBC are estimated. Electronic structure calculations show that the TBBC is an indirect semiconductor with a bandgap of 0.66 eV. The ideal tensile strength of TBBC is high in [0001] and [11¯00] directions, but is weak along [12¯10] direction.

  19. Oil refining in a CO2 constrained world: Effects of carbon pricing on refineries globally

    International Nuclear Information System (INIS)

    Abdul-Manan, Amir F.N.; Arfaj, Abdullah; Babiker, Hassan

    2017-01-01

    Six aggregated refinery linear programming (LP) models were developed to represent actual refineries in North America, Latin America, Europe (including the CIS), Middle East, Asia (excluding China) and China. The models were used to conduct regional comparative assessments and to evaluate the effects of carbon pricing on refinery operations globally. We found that the average refinery energy efficiencies for the regions were estimated to range from 92.2% to 95.2%. The well-to-refinery gate carbon intensities for gasoline, diesel and jet fuels were estimated to be 17.1 (16.4–19.4), 13.3 (12.5–14.2) and 10.1 (9.6–10.8) gCO2eq/MJ, respectively. If refineries are forced to at least meet the 2014 regional volume demands for oil products, pricing CO 2 would not have an impact on either refinery productions, efficiency or emissions. If refineries are allowed to re-optimize production slates to reduce CO 2 emissions, refineries would opt to increase gasoline yield at the expense of diesel. This is counter intuitive since gasoline has a higher carbon intensity than diesel. The refinery bias against dieselization creates a supply preference toward a less efficient transportation end use. Here, we argue that if carbon pricing is not administered properly, this can lead to emissions leakage from refineries to the road transport sector. - Highlights: • Investigate actual refinery productions in 6 regions globally. • Refineries already operate at the most efficient levels. • Complex refineries tolerate higher CO 2 prices better. • Carbon pricing induces bias against dieselization. • Identify potential emissions leakage.

  20. Electrochemical performance of carbon-coated lithium manganese silicate for asymmetric hybrid supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Karthikeyan, K.; Lee, S.B.; Jang, I.C.; Lim, H.H.; Lee, Y.S. [Faculty of Applied Chemical Engineering, Chonnam National University, Gwangju 500-757 (Korea); Aravindan, V. [The Research Institute for Catalysis, Chonnam National University, Gwangju 500-757 (Korea); Park, G.J.; Yoshio, M. [Department of Applied Chemistry, Saga University, Saga 840-8502 (Japan)

    2010-06-01

    Nanoscale carbon-coated Li{sub 2}MnSiO{sub 4} powder is prepared using a conventional solid-state method and can be used as the negative electrode in a Li{sub 2}MnSiO{sub 4}/activated carbon (AC) hybrid supercapacitor. Carbon-coated Li{sub 2}MnSiO{sub 4} material presents a well-developed orthorhombic crystal structure with a Pmn2{sub 1} space group, although there is a small impurity of MnO. The maximum specific capacitance of the Li{sub 2}MnSiO{sub 4}/AC hybrid supercapacitor is 43.2 F g{sup -1} at 1 mA cm{sup -2} current density. The cell delivers a specific energy as high as 54 Wh kg{sup -1} at a specific power of 150 W kg{sup -1} and also exhibits an excellent cycle performance with more than 99% columbic efficiency and the maintenance of 85% of its initial capacitance after 1000 cycles. (author)

  1. Storing in carbon nano structures for hybrid systems solar hydrogen

    International Nuclear Information System (INIS)

    Marazzi, R.; Zini, G.; Tartarini, P.

    2009-01-01

    We have developed a hybrid energy system for converting energy from renewable sources and its storage in the form of hydrogen. The storage uses activated carbon and the methodology was modelled mathematically and simulated in numerical software. The results show that storage compression is cheaper storage for liquefaction. [it

  2. Multi-objective hybrid PSO-APO algorithm based security constrained optimal power flow with wind and thermal generators

    Directory of Open Access Journals (Sweden)

    Kiran Teeparthi

    2017-04-01

    Full Text Available In this paper, a new low level with teamwork heterogeneous hybrid particle swarm optimization and artificial physics optimization (HPSO-APO algorithm is proposed to solve the multi-objective security constrained optimal power flow (MO-SCOPF problem. Being engaged with the environmental and total production cost concerns, wind energy is highly penetrating to the main grid. The total production cost, active power losses and security index are considered as the objective functions. These are simultaneously optimized using the proposed algorithm for base case and contingency cases. Though PSO algorithm exhibits good convergence characteristic, fails to give near optimal solution. On the other hand, the APO algorithm shows the capability of improving diversity in search space and also to reach a near global optimum point, whereas, APO is prone to premature convergence. The proposed hybrid HPSO-APO algorithm combines both individual algorithm strengths, to get balance between global and local search capability. The APO algorithm is improving diversity in the search space of the PSO algorithm. The hybrid optimization algorithm is employed to alleviate the line overloads by generator rescheduling during contingencies. The standard IEEE 30-bus and Indian 75-bus practical test systems are considered to evaluate the robustness of the proposed method. The simulation results reveal that the proposed HPSO-APO method is more efficient and robust than the standard PSO and APO methods in terms of getting diverse Pareto optimal solutions. Hence, the proposed hybrid method can be used for the large interconnected power system to solve MO-SCOPF problem with integration of wind and thermal generators.

  3. An analysis of calcium carbonate/polymer hybrid crystals applying contrast variation SANS

    International Nuclear Information System (INIS)

    Endo, Hitoshi; Schwahn, Dietmar; Coelfen, Helmut

    2004-01-01

    The geometry of calcium carbonate (CaCO 3 )/polymer hybrid crystals was investigated by means of the contrast variation small angle neutron scattering. Our sophisticated contrast variation method led to decomposition of the measured scattering intensities into partial scattering functions of each component. These decomposed partial scattering functions gave detailed information on each component in the hybrid particle. Especially, on the basis of the Babinet principle (or incompressibility hypothesis), the comparison of the cross terms led to the relationships of each scattering amplitude. In this way, we could determine the geometry of the hybrid crystals in detail

  4. An analysis of calcium carbonate/polymer hybrid crystals applying contrast variation SANS

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Hitoshi; Schwahn, Dietmar; Coelfen, Helmut

    2004-07-15

    The geometry of calcium carbonate (CaCO{sub 3})/polymer hybrid crystals was investigated by means of the contrast variation small angle neutron scattering. Our sophisticated contrast variation method led to decomposition of the measured scattering intensities into partial scattering functions of each component. These decomposed partial scattering functions gave detailed information on each component in the hybrid particle. Especially, on the basis of the Babinet principle (or incompressibility hypothesis), the comparison of the cross terms led to the relationships of each scattering amplitude. In this way, we could determine the geometry of the hybrid crystals in detail.

  5. Integrating satellite retrieved leaf chlorophyll into land surface models for constraining simulations of water and carbon fluxes

    KAUST Repository

    Houborg, Rasmus

    2013-07-01

    In terrestrial biosphere models, key biochemical controls on carbon uptake by vegetation canopies are typically assigned fixed literature-based values for broad categories of vegetation types although in reality significant spatial and temporal variability exists. Satellite remote sensing can support modeling efforts by offering distributed information on important land surface characteristics, which would be very difficult to obtain otherwise. This study investigates the utility of satellite based retrievals of leaf chlorophyll for estimating leaf photosynthetic capacity and for constraining model simulations of water and carbon fluxes. © 2013 IEEE.

  6. Facile preparation of well-combined lignin-based carbon/ZnO hybrid composite with excellent photocatalytic activity

    Science.gov (United States)

    Wang, Huan; Qiu, Xueqing; Liu, Weifeng; Yang, Dongjie

    2017-12-01

    In this work, a novel lignin-based carbon/ZnO (LC/ZnO) hybrid composite with excellent photocatalytic performance was prepared through a convenient and environment friendly method using alkali lignin (AL) as carbon source. The morphological, microstructure and optical properties of the as-prepared LC/ZnO hybrid composite was characterized with scanning electron microscope (SEM), X-ray diffraction (XRD), Raman and UV-vis. The resulting LC/ZnO hybrid is composed of highly dispersed ZnO nanoparticles embedded on a lignin-based carbon nanosheet, showing excellent photogenerated electrons and holes separation and migration efficiency. The photocatalytic activity of LC/ZnO was much higher than the pure ZnO. The LC/ZnO hybrid composite showed different photocatalytic mechanism for degradation of negative methyl orange (MO) and positive Rhodamine B (RhB). It showed that h+ was the main photocatalytic active group during the degradation of MO, ·O2- and ·OH were the photocatalytic active groups during degradation of RhB. This reported photocatalyst with selective degradation of positive and negative organic dyes may have a great application prospect for photoelectric conversion and catalytic materials. Results of this work were of practical importance for high-valued utilization of lignin for carbon materials.

  7. Constraining the Exchange of Carbon and Nitrogen in Eastern Long Island Sound

    Science.gov (United States)

    Byrd, A.; Warren, J. K.; Vlahos, P.; Whitney, M. M.

    2017-12-01

    Long Island Sound (LIS) is an urban estuary on the US east coast that undergoes seasonal hypoxia in its western and central regions. Currently, the budgets of both carbon and nitrogen in LIS remain unbalanced, despite their importance to the efficient and strategic management of the health of coastal and aquatic ecosystems. In this study, we evaluated the exchange values of C and N at the mouth of LIS (the Race), in order to constrain export through this important boundary. Discreet water samples were collected during four 15 km transects over the Race at five stations and three depths each station to resolve the temporal variability over a complete tidal cycle, in order to assess both net flux and variations across the tidal period. By evaluating both the particulate and dissolved pools of carbon (POC, PIC, DOC, DIC) and nitrogen (PON, DON, DIN) during the spring, summer and winter (high and low flow conditions) and pairing these measurements with physical data, we were able to identify a variety of forcing and export regimes. Preliminary results indicate the importance of spatial and tidal variability on flux estimates and show little or no export (and sometimes import) of nitrogen and significant export of organic carbon.

  8. Dynamic hybrid life cycle assessment of energy and carbon of multicrystalline silicon photovoltaic systems.

    Science.gov (United States)

    Zhai, Pei; Williams, Eric D

    2010-10-15

    This paper advances the life cycle assessment (LCA) of photovoltaic systems by expanding the boundary of the included processes using hybrid LCA and accounting for the technology-driven dynamics of embodied energy and carbon emissions. Hybrid LCA is an extended method that combines bottom-up process-sum and top-down economic input-output (EIO) methods. In 2007, the embodied energy was 4354 MJ/m(2) and the energy payback time (EPBT) was 2.2 years for a multicrystalline silicon PV system under 1700 kWh/m(2)/yr of solar radiation. These results are higher than those of process-sum LCA by approximately 60%, indicating that processes excluded in process-sum LCA, such as transportation, are significant. Even though PV is a low-carbon technology, the difference between hybrid and process-sum results for 10% penetration of PV in the U.S. electrical grid is 0.13% of total current grid emissions. Extending LCA from the process-sum to hybrid analysis makes a significant difference. Dynamics are characterized through a retrospective analysis and future outlook for PV manufacturing from 2001 to 2011. During this decade, the embodied carbon fell substantially, from 60 g CO(2)/kWh in 2001 to 21 g/kWh in 2011, indicating that technological progress is realizing reductions in embodied environmental impacts as well as lower module price.

  9. Synthesis and mechanical behavior of carbon nanotube-magnesium composites hybridized with nanoparticles of alumina

    International Nuclear Information System (INIS)

    Thakur, Sanjay Kumar; Srivatsan, T.S.; Gupta, Manoj

    2007-01-01

    Carbon nanotubes reinforced magnesium based composites were prepared with diligence and care using the powder metallurgy route coupled with rapid microwave sintering. Nanometer-sized particles of alumina were used to hybridize the carbon nanotubes reinforcement in the magnesium matrix so as to establish the intrinsic influence of hybridization on mechanical behavior of the resultant composite material. The yield strength, tensile strength and strain-to-failure of the carbon nanotubes-magnesium composites were found to increase with the addition of nanometer-sized alumina particles to the composite matrix. Scanning electron microscopy observations of the fracture surfaces of the samples deformed and failed in uniaxial tension revealed the presence of cleavage-like features on the fracture surface indicative of the occurrence of locally brittle fracture mechanism in the composite microstructure

  10. Perspectives on State-of-the-Art Carbon Nanotube/Polyaniline and Graphene/Polyaniline Composites for Hybrid Supercapacitor Electrodes.

    Science.gov (United States)

    Srikanth, Vadali V S S; Ramana, Gedela Venkata; Kumar, Puttapati Sampath

    2016-03-01

    Supercapacitors are attractive alternative energy storage sources. They offer high energy/power density with other characteristics like fast discharge/charge time, long operation stability, safety etc. In a supercapacitor, working electrode material is the principal constituent. At present there are numerous electrode materials (with properties) suitable for their use in hybrid type supercapacitors. Carbon/polyaniline (PANi) composites are one class of such electrode materials. Here, perspectives on state-of-the-art carbon/PANi composites namely carbon nanotube/polyaniline and graphene/polyaniline composites expedient as hybrid type supercapacitor electrode materials will be presented.

  11. A Numerical Study on Electrical Percolation of Polymer-Matrix Composites with Hybrid Fillers of Carbon Nanotubes and Carbon Black

    Directory of Open Access Journals (Sweden)

    Yuli Chen

    2014-01-01

    Full Text Available The electrical percolation of polymer-matrix composites (PMCs containing hybrid fillers of carbon nanotubes (CNTs and carbon black (CB is estimated by studying the connection possibility of the fillers using Monte Carlo simulation. The 3D simulation model of CB-CNT hybrid filler is established, in which CNTs are modeled by slender capped cylinders and CB groups are modeled by hypothetical spheres with interspaces because CB particles are always agglomerated. The observation on the effects of CB and CNT volume fractions and dimensions on the electrical percolation threshold of hybrid filled composites is then carried out. It is found that the composite electrical percolation threshold can be reduced by increasing CNT aspect ratio, as well as increasing the diameter ratio of CB groups to CNTs. And adding CB into CNT composites can decrease the CNT volume needed to convert the composite conductivity, especially when the CNT volume fraction is close to the threshold of PMCs with only CNT filler. Different from previous linear assumption, the nonlinear relation between CB and CNT volume fractions at composite percolation threshold is revealed, which is consistent with the synergistic effect observed in experiments. Based on the nonlinear relation, the estimating equation for the electrical percolation threshold of the PMCs containing CB-CNT hybrid fillers is established.

  12. Electroresponsive polymer-carbon nanotube hydrogel hybrids for pulsatile drug delivery in vivo.

    Science.gov (United States)

    Servant, Ania; Methven, Laura; Williams, Rhodri P; Kostarelos, Kostas

    2013-06-01

    Drug release triggered by an external non-invasive stimulus is of great interest for the development of new drug delivery systems. The preparation of an electroresponsive multiwalled carbon nanotube/poly(methylacrylic acid) (MWNT/PMAA)-based hybrid material is reported. The hydrogel hybrids achieve a controlled drug release upon the ON/OFF application of an electric field, giving rise to in vitro and in vivo pulsatile release profiles. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Self-diagnosis of structures strengthened with hybrid carbon-fiber-reinforced polymer sheets

    Science.gov (United States)

    Wu, Z. S.; Yang, C. Q.; Harada, T.; Ye, L. P.

    2005-06-01

    The correlation of mechanical and electrical properties of concrete beams strengthened with hybrid carbon-fiber-reinforced polymer (HCFRP) sheets is studied in this paper. Two types of concrete beams, with and without reinforcing bars, are strengthened with externally bonded HCFRP sheets, which have a self-structural health monitoring function due to the electrical conduction and piezoresistivity of carbon fibers. Parameters investigated include the volume fractions and types of carbon fibers. According to the investigation, it is found that the hybridization of uniaxial HCFRP sheets with several different types of carbon fibers is a viable method for enhancing the mechanical properties and obtaining a built-in damage detection function for concrete structures. The changes in electrical resistance during low strain ranges before the rupture of carbon fibers are generally smaller than 1%. Nevertheless, after the gradual ruptures of carbon fibers, the electrical resistance increases remarkably with the strain in a step-wise manner. For the specimens without reinforcing bars, the electrical behaviors are not stable, especially during the low strain ranges. However, the electrical behaviors of the specimens with reinforcing bars are relatively stable, and the whole range of self-sensing function of the HCFRP-strengthened RC structures has realized the conceptual design of the HCFRP sensing models and is confirmed by the experimental investigations. The relationships between the strain/load and the change in electrical resistance show the potential self-monitoring capacity of HCFRP reinforcements used for strengthening concrete structures.

  14. Water-processed carbon nanotube/graphene hybrids with enhanced field emission properties

    International Nuclear Information System (INIS)

    Song, Meng; Xu, Peng; Wang, Xu; Wu, Huizhen; Wang, Miao; Song, Yenan; Li, Zhenhua; Zhao, Pei; Shang, Xuefu

    2015-01-01

    Integrating carbon nanotubes (CNTs) and graphene into hybrid structures provides a novel approach to three dimensional (3D) materials with advantageous properties. Here we present a water-processing method to create integrated CNT/graphene hybrids and test their field emission properties. With an optimized mass ratio of CNTs to graphene, the hybrid shows a significantly enhanced field emission performance, such as turn-on electric field of 0.79 V/μm, threshold electric field of 1.05 V/μm, maximum current density of 0.1 mA/cm 2 , and field enhancement factor of ∼1.3 × 10 4 . The optimized mass ratio for field emission emphasizes the importance of both CNTs and graphene in the hybrid. We also hypothesize a possible mechanism for this enhanced field emission performance from the CNT/graphene hybrid. During the solution treatment, graphene oxide behaves as surfactant sheets for CNTs to form a well dispersed solution, which leads to a better organized 3D structure with more conducting channels for electron transport

  15. Water-processed carbon nanotube/graphene hybrids with enhanced field emission properties

    Energy Technology Data Exchange (ETDEWEB)

    Song, Meng; Xu, Peng; Wang, Xu; Wu, Huizhen; Wang, Miao, E-mail: peizhao@zju.edu.cn, E-mail: miaowang@css.zju.edu.cn [Department of Physics, Zhejiang University, Hangzhou 310027 (China); Song, Yenan; Li, Zhenhua; Zhao, Pei, E-mail: peizhao@zju.edu.cn, E-mail: miaowang@css.zju.edu.cn [Institute of Applied Mechanics, Zhejiang University, Hangzhou 310027 (China); Shang, Xuefu [Department of Physics, Faculty of Science, Jiangsu University, Zhenjiang 212013 (China)

    2015-09-15

    Integrating carbon nanotubes (CNTs) and graphene into hybrid structures provides a novel approach to three dimensional (3D) materials with advantageous properties. Here we present a water-processing method to create integrated CNT/graphene hybrids and test their field emission properties. With an optimized mass ratio of CNTs to graphene, the hybrid shows a significantly enhanced field emission performance, such as turn-on electric field of 0.79 V/μm, threshold electric field of 1.05 V/μm, maximum current density of 0.1 mA/cm{sup 2}, and field enhancement factor of ∼1.3 × 10{sup 4}. The optimized mass ratio for field emission emphasizes the importance of both CNTs and graphene in the hybrid. We also hypothesize a possible mechanism for this enhanced field emission performance from the CNT/graphene hybrid. During the solution treatment, graphene oxide behaves as surfactant sheets for CNTs to form a well dispersed solution, which leads to a better organized 3D structure with more conducting channels for electron transport.

  16. The hybrid nanostructure of MnCo2O4.5 nanoneedle/carbon aerogel for symmetric supercapacitors with high energy density

    Science.gov (United States)

    Hao, Pin; Zhao, Zhenhuan; Li, Liyi; Tuan, Chia-Chi; Li, Haidong; Sang, Yuanhua; Jiang, Huaidong; Wong, C. P.; Liu, Hong

    2015-08-01

    Current applications of carbon-based supercapacitors are limited by their low energy density. One promising strategy to enhance the energy density is to couple metal oxides with carbon materials. In this study, a porous MnCo2O4.5 nanoneedle/carbon aerogel hybrid nanostructure was synthesized by assembling MnCo2O4.5 nanoneedle arrays on the surface of channel walls of hierarchical porous carbon aerogels derived from chitosan for the supercapacitor application. The synthetic process of the hybrid nanostructure involves two steps, i.e. the growth of Mn-Co precursors on carbon aerogel by a hydrothermal process and the conversion of the precursor into MnCo2O4.5 nanoneedles by calcination. The carbon aerogel exhibits a high electrical conductivity, high specific surface area and porous structure, ensuring high electrochemical performance of the hybrid nanostructure when coupled with the porous MnCo2O4.5 nanoneedles. The symmetric supercapacitor using the MnCo2O4.5 nanoneedle/carbon aerogel hybrid nanostructure as the active electrode material exhibits a high energy density of about 84.3 Wh kg-1 at a power density of 600 W kg-1. The voltage window is as high as 1.5 V in neutral aqueous electrolytes. Due to the unique nanostructure of the electrodes, the capacitance retention reaches 86% over 5000 cycles.Current applications of carbon-based supercapacitors are limited by their low energy density. One promising strategy to enhance the energy density is to couple metal oxides with carbon materials. In this study, a porous MnCo2O4.5 nanoneedle/carbon aerogel hybrid nanostructure was synthesized by assembling MnCo2O4.5 nanoneedle arrays on the surface of channel walls of hierarchical porous carbon aerogels derived from chitosan for the supercapacitor application. The synthetic process of the hybrid nanostructure involves two steps, i.e. the growth of Mn-Co precursors on carbon aerogel by a hydrothermal process and the conversion of the precursor into MnCo2O4.5 nanoneedles by

  17. Biocompatible multi-walled carbon nanotube–CdTe quantum dot–polymer hybrids for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Baslak, Canan, E-mail: cananbaslak@gmail.com [Advanced Technology Research and Application Center, Selcuk University, 42075 Konya (Turkey); Department of Chemistry, Faculty of Science, Selcuk University, 42075 Konya (Turkey); Demirel Kars, Meltem, E-mail: dmeltem@yahoo.com [Advanced Technology Research and Application Center, Selcuk University, 42075 Konya (Turkey); Sarayonu Vocational High School, Selcuk University, 42430 Konya (Turkey); Karaman, Mustafa; Kus, Mahmut [Advanced Technology Research and Application Center, Selcuk University, 42075 Konya (Turkey); Department of Chemical Engineering, Faculty of Engineering, Selcuk University, 42075 Konya (Turkey); Cengeloglu, Yunus; Ersoz, Mustafa [Advanced Technology Research and Application Center, Selcuk University, 42075 Konya (Turkey); Department of Chemistry, Faculty of Science, Selcuk University, 42075 Konya (Turkey)

    2015-04-15

    Herein we report the synthesis of polymer coated quantum dots (QDs)–carbon nanotube composite material with high biocompatibility and low cellular toxicity. The synthesized multi-walled carbon nanotube (MWCNT)–QD-(-poly(glycidyl methacrylate)) (pGMA) hybrids were characterized using X-ray photoelectron spectroscopy, laser scanning confocal microscopy, transmission electron microscopy and scanning electron microscopy. The results showed that quantum dots were well-distributed on nanotube surfaces in high density. The toxicological assessments of QDs and MWCNT–QD–polymer hybrids in human mammary carcinoma cells and their fluorescence imaging in living cell system were carried out. MWCNT–QD–polymer hybrids possess intense red fluorescence signal under confocal microscopy and good fluorescence stability over 6-h exposure in living cell system. The toxicity comparison of QDs and MWCNT–QD–polymer hybrids has shown that the existence of PGMA thin coating on MWCNT–QD hybrid surface decreased the cellular toxicity and increased biocompatibility. - Highlights: • We report that polymer coating of QDs on CNTs increased their biocompatibility by decreasing cellular toxicity. • QD–CNT polymer hybrid material may be proposed as a good diagnostic agent to visualize cancer cells which may be improved as a therapeutic carrier in future. • Coating QDs with polymer seems to be a right choice to be used in medicinal applications both for diagnosis and for therapy.

  18. Biocompatible multi-walled carbon nanotube–CdTe quantum dot–polymer hybrids for medical applications

    International Nuclear Information System (INIS)

    Baslak, Canan; Demirel Kars, Meltem; Karaman, Mustafa; Kus, Mahmut; Cengeloglu, Yunus; Ersoz, Mustafa

    2015-01-01

    Herein we report the synthesis of polymer coated quantum dots (QDs)–carbon nanotube composite material with high biocompatibility and low cellular toxicity. The synthesized multi-walled carbon nanotube (MWCNT)–QD-(-poly(glycidyl methacrylate)) (pGMA) hybrids were characterized using X-ray photoelectron spectroscopy, laser scanning confocal microscopy, transmission electron microscopy and scanning electron microscopy. The results showed that quantum dots were well-distributed on nanotube surfaces in high density. The toxicological assessments of QDs and MWCNT–QD–polymer hybrids in human mammary carcinoma cells and their fluorescence imaging in living cell system were carried out. MWCNT–QD–polymer hybrids possess intense red fluorescence signal under confocal microscopy and good fluorescence stability over 6-h exposure in living cell system. The toxicity comparison of QDs and MWCNT–QD–polymer hybrids has shown that the existence of PGMA thin coating on MWCNT–QD hybrid surface decreased the cellular toxicity and increased biocompatibility. - Highlights: • We report that polymer coating of QDs on CNTs increased their biocompatibility by decreasing cellular toxicity. • QD–CNT polymer hybrid material may be proposed as a good diagnostic agent to visualize cancer cells which may be improved as a therapeutic carrier in future. • Coating QDs with polymer seems to be a right choice to be used in medicinal applications both for diagnosis and for therapy

  19. Electrochemical study of nitrobenzene reduction using novel Pt nanoparticles/macroporous carbon hybrid nanocomposites

    International Nuclear Information System (INIS)

    Zhang Yufan; Zeng Lijun; Bo Xiangjie; Wang Huan; Guo Liping

    2012-01-01

    Graphical abstract: A one-step microwave-assisted route for rapidly synthesizing Pt nanoparticles ensemble on macroporous carbon hybrid nanocomposites (PNMPC) has been reported. As a novel electrode material, the excellent electrochemical behavior of nitrobenzene was investigated thoroughly at the PNMPC modified glassy carbon electrode. And moreover, the modified electrode was successfully applied to the determination of nitrobenzene in real samples. Highlights: ► One-step microwave-assisted heating synthesis Pt nanoparticles/macroporous carbon hybrid nanocomposites (PNMPC). ► Catalytic rate constant being 3.14 × 10 4 M −1 s −1 for NB in pH 7.0. ► Sensitive electrochemical detection of NB at the PNMPC/Nafion/GC electrode. ► The electrode showing excellent anti-interference ability and good stability for NB. - Abstract: Novel Pt nanoparticles (PN) ensemble on macroporous carbon (MPC) hybrid nanocomposites (PNMPC) were prepared through a rapidly and simple one-step microwave-assisted heating procedure. The obtained PNMPC was characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and electrochemical methods. The electrochemical reduction of nitrobenzene (NB) was thoroughly investigated at the PNMPC modified glassy carbon (GC) electrode, and the catalytic rate constant was calculated to be 3.14 × 10 4 M −1 s −1 for NB. A sensitive NB sensor was developed based on the PNMPC/GC electrode, which showed a wide linear range (1–200 μM), low detection limit (50 nM), high sensitivity (6.93 μA μM −1 ), excellent anti-interference ability and good stability. And moreover, the electrode was successfully applied to the determination of NB in real samples.

  20. Analysis of market penetration of renewable energy alternatives under uncertain and carbon constrained world

    Science.gov (United States)

    Future energy prices and supply, availability and costs can have a significant impact on how fast and cost effectively we could abate carbon emissions. Two-staged decision making methods embedded in U.S. EPA's MARKAL modeling system will be utilized to find the most robust mitig...

  1. High adhesion transparent conducting films using graphene oxide hybrid carbon nanotubes

    International Nuclear Information System (INIS)

    Da, Shi-Xun; Wang, Jie; Geng, Hong-Zhang; Jia, Song-Lin; Xu, Chun-Xia; Li, Lin-Ge; Shi, Pei-Pei; Li, Guangfen

    2017-01-01

    Graphical abstract: The GO hybrid CNTs to fabricate TCFs could dramatically enhance the conductivity, adhesion, flatness, and wettability of the films, all these improvements are advantageous for optoelectronic applications. - Highlights: • TCFs were fabricated using GO/CNT hybrid inks by a simple spray method. • Conductivity of TCFs was improved through the hybrid of GO/CNT, sheet resistance of TCFs was 146 Ω/sq at the transmittance of 86.0% when the ratio of GO/CNT got 1.5:1.0. • The flatness and wettability of TCFs were improved dramatically, which is advantageous for the solution-based processing of organic electronics for spraying and printing. • The adhesion of the TCFs increased dramatically with the raise of the ratio GO/CNT hybrid. - Abstract: Flexible transparent conducting films (TCFs) with carbon nanotubes (CNTs) have attracted more and more attention for their wide range of potential applications. While, there are still some problems to be solved on several aspects. In this study, a graphene oxide/carbon nanotube (GO/CNT) hybrid TCF was fabricated through the simple spray coating method. GO sheets were introduced to form new electron transporting channels. It was found that the best optoelectronic property films were fabricated when the ratio of GO/CNT is 1.5:1.0, which the sheet resistance of the film was found to be 146 Ω/sq at the transmittance of 86.0%. Due to the two-dimensional structure and the oxidation groups of GO sheets, flatness and wettability of the electrode surface was improved obviously. Adhesion factor of the TCFs was calculated by the change of transparent and sheet resistance after trial test, the addition of GO sheets enhanced the adhesion dramatically and the mechanism was analyzed. Improvements of conductivity, flatness, wettability and adhesion above are all advantageous for the solution-based processing of organic electronics for spraying and printing.

  2. High adhesion transparent conducting films using graphene oxide hybrid carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Da, Shi-Xun; Wang, Jie; Geng, Hong-Zhang, E-mail: genghz@tjpu.edu.cn; Jia, Song-Lin; Xu, Chun-Xia; Li, Lin-Ge; Shi, Pei-Pei; Li, Guangfen

    2017-01-15

    Graphical abstract: The GO hybrid CNTs to fabricate TCFs could dramatically enhance the conductivity, adhesion, flatness, and wettability of the films, all these improvements are advantageous for optoelectronic applications. - Highlights: • TCFs were fabricated using GO/CNT hybrid inks by a simple spray method. • Conductivity of TCFs was improved through the hybrid of GO/CNT, sheet resistance of TCFs was 146 Ω/sq at the transmittance of 86.0% when the ratio of GO/CNT got 1.5:1.0. • The flatness and wettability of TCFs were improved dramatically, which is advantageous for the solution-based processing of organic electronics for spraying and printing. • The adhesion of the TCFs increased dramatically with the raise of the ratio GO/CNT hybrid. - Abstract: Flexible transparent conducting films (TCFs) with carbon nanotubes (CNTs) have attracted more and more attention for their wide range of potential applications. While, there are still some problems to be solved on several aspects. In this study, a graphene oxide/carbon nanotube (GO/CNT) hybrid TCF was fabricated through the simple spray coating method. GO sheets were introduced to form new electron transporting channels. It was found that the best optoelectronic property films were fabricated when the ratio of GO/CNT is 1.5:1.0, which the sheet resistance of the film was found to be 146 Ω/sq at the transmittance of 86.0%. Due to the two-dimensional structure and the oxidation groups of GO sheets, flatness and wettability of the electrode surface was improved obviously. Adhesion factor of the TCFs was calculated by the change of transparent and sheet resistance after trial test, the addition of GO sheets enhanced the adhesion dramatically and the mechanism was analyzed. Improvements of conductivity, flatness, wettability and adhesion above are all advantageous for the solution-based processing of organic electronics for spraying and printing.

  3. A Review of the Synthesis and Photoluminescence Properties of Hybrid ZnO and Carbon Nanomaterials

    Directory of Open Access Journals (Sweden)

    Protima Rauwel

    2016-01-01

    Full Text Available Photoluminescent ZnO carbon nanomaterials are an emerging class of nanomaterials with unique optical properties. They each, ZnO and carbon nanomaterials, have an advantage of being nontoxic and environmentally friendly. Their cost-effective production methods along with simple synthesis routes are also of interest. Moreover, ZnO presents photoluminescence emission in the UV and visible region depending on the synthesis routes, shape, size, deep level, and surface defects. When combined with carbon nanomaterials, modification of surface defects in ZnO allows tuning of these photoluminescence properties to produce, for example, white light. Moreover, efficient energy transfer from the ZnO to carbon nanostructures makes them suitable candidates not only in energy harvesting applications but also in biosensors, photodetectors, and low temperature thermal imaging. This work reviews the synthesis and photoluminescence properties of 3 carbon allotropes: carbon quantum or nanodots, graphene, and carbon nanotubes when hybridized with ZnO nanostructures. Various synthesis routes for the hybrid materials with different morphologies of ZnO are presented. Moreover, differences in photoluminescence emission when combining ZnO with each of the three different allotropes are analysed.

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

    International Nuclear Information System (INIS)

    Dong, Huijuan; Geng, Yong; Xi, Fengming; Fujita, Tsuyoshi

    2013-01-01

    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

  5. Gas-Transport-Property Performance of Hybrid Carbon Molecular Sieve−Polymer Materials

    KAUST Repository

    Das, Mita

    2010-10-06

    High-performance hybrid materials using carbon molecular sieve materials and 6FDA-6FpDA were produced. A detailed analysis of the effects of casting processes and the annealing temperature is reported. Two existing major obstacles, sieve agglomeration and residual stress, were addressed in this work, and subsequently a new membrane formation technique was developed to produce high-performing membranes. The successfully improved interfacial region of the hybrid membranes allows the sieves to increase the selectivity of the membranes above the neat polymer properties. Furthermore, an additional performance enhancement was seen with increased sieve loading in the hybrid membranes, leading to an actual performance above the upper bound for pure polymer membranes. The membranes were also tested under a mixed-gas environment, which further demonstrated promising results. © 2010 American Chemical Society.

  6. Influence of the Hybrid Combination of Multiwalled Carbon Nanotubes and Graphene Oxide on Interlaminar Mechanical Properties of Carbon Fiber/Epoxy Laminates

    Science.gov (United States)

    Rodríguez-González, J. A.; Rubio-González, C.; Jiménez-Mora, M.; Ramos-Galicia, L.; Velasco-Santos, C.

    2017-10-01

    An effective strategy to improve the mode I and mode II interlaminar fracture toughness (G IC and G IIC ) of unidirectional carbon fiber/epoxy (CF/E) laminates using a hybrid combination of multiwalled carbon nanotubes (MWCNTs) and graphene oxide (GO) is reported. Double cantilever beam (DCB) and end notched flexure (ENF) tests were conducted to evaluate the G IC and G IIC of the CF/E laminates fabricated with sprayed MWCNTs, GO and MWCNTs/GO hybrid. Scanning electron microscopy was employed to observe the fracture surfaces of tested DCB and ENF specimens. Experimental results showed the positive effect on the G IC and G IIC by 17% and 14% improvements on CF/E laminates with 0.25 wt.% MWCNTs/GO hybrid content compared to the neat CF/E. Also, the interlaminar shear strength value was increased for MWCNTs/GO-CF/E laminates. A synergetic effect between MWCNTs and GO resulted in improved interlaminar mechanical properties of CF/E laminates made by prepregs.

  7. Performance evaluation and parametric optimum design of a molten carbonate fuel cell-thermophotovoltaic cell hybrid system

    International Nuclear Information System (INIS)

    Yang, Zhimin; Liao, Tianjun; Zhou, Yinghui; Lin, Guoxing; Chen, Jincan

    2016-01-01

    Highlights: • A molten carbonate fuel cell-thermophotovoltaic cell hybrid system is established. • The performance characteristics of the hybrid system are systematically evaluated. • The optimal regions of the power output density and efficiency are determined. • The values of key parameters at the maximum power output density are calculated. • The proposed system is proved to have advantages over other hybrid systems. - Abstract: A new model of the hybrid system composed of a molten carbonate fuel cell (MCFC) and a thermophotovoltaic cell (TPVC) is proposed to recovery the waste heat produced by the MCFC. Expressions for the power output and the efficiency of the hybrid system are analytically derived. The performance characteristics of the hybrid system are evaluated. It is found that when the current density of the MCFC, voltage output of the TPVC, electrode area ratio of the MCFC to the TPVC, and energy gap of the material in the photovoltaic cell are optimally chosen, the maximum power output density of the hybrid system is obviously larger than that of the single MCFC. Moreover, the improved percentages of the maximum power output density of the proposed model relative to that of the single MCFC are calculated for differently operating temperatures of the MCFC and are compared with those of some MCFC-based hybrid systems reported in the literature, and consequently, the advantages of the MCFC-TPVC hybrid system are revealed.

  8. Effect of sp3-hybridized defects on the oscillatory behavior of carbon nanotube oscillators

    International Nuclear Information System (INIS)

    Guo, Taiyu; Ding, Tony Weixi; Pei, Qing-Xiang; Zhang, Yong-Wei

    2011-01-01

    Using molecular dynamics simulations, we investigate the oscillatory behaviors of carbon nanotube oscillators containing sp 3 -hybridized defects formed by hydrogen chemisorption. It is found that the presence of these defects significantly affects the kinetic and potential energies of the nanotube systems, which in turn affects their oscillation periods and frequencies. We have also studied the oscillatory characteristics of the oscillators containing sp 3 -hybridized Stone-Wales defects. Our results show that it is possible to control the motion of the inner nanotube by introducing sp 3 -hybridized defects on the outer nanotube, which provides a potential way to tune the oscillatory behavior of nanotube oscillators. -- Highlights: → sp 3 -hybridized defects increase energy dissipation. → sp 3 -hybridized defects arranged in a row have stronger effect than that in a ring. → sp 3 -hybridized defects reduces the effect of SW defects.

  9. Interfacial adhesion improvement in carbon fiber/carbon nanotube reinforced hybrid composites by the application of a reactive hybrid resin initiated by gamma irradiation

    Science.gov (United States)

    Szebényi, G.; Faragó, D.; Lámfalusi, Cs.; Göbl, R.

    2018-04-01

    Interfacial adhesion is a key factor in composite materials. The effective co-working of the reinforcing materials and matrix is essential for the proper load transfer between them, and to achieve the desired reinforcing effect. In case of nanocomposites, especially carbon nanotube (CNT) reinforced nanocomposites the adhesion between the CNTs and the polymer matrix is poor. To improve the interfacial adhesion and exploit the reinforcing effect of these nanoparticles a two step curable epoxy (EP)/vinylester (VE) hybrid resin system was developed where the EP is cured using hardener in the first step, during the composite production, and in the second step the curing of the VE is initiated by gamma irradiation, which also activates the reinforcing materials and the cured matrix component. A total of six carbon fiber reinforced composite systems were compared with neat epoxy and EP/VE hybrid matrices with and without chemical initiator and MWCNT nano-reinforcement. The effect of gamma irradiation was investigated at four absorbed dose levels. According to our three point bending and interlaminar shear test results the adhesion has improved between all constituents of the composite system. It was demonstrated that gamma irradiation has beneficial effect on the static mechanical, especially interlaminar properties of both micro- and nanocomposites in terms of modulus, strength and interlaminar shear strength.

  10. Activated carbon-supported CuO nanoparticles: a hybrid material for carbon dioxide adsorption

    Science.gov (United States)

    Boruban, Cansu; Esenturk, Emren Nalbant

    2018-03-01

    Activated carbon-supported copper(II) oxide (CuO) nanoparticles were synthesized by simple impregnation method to improve carbon dioxide (CO2) adsorption capacity of the support. The structural and chemical properties of the hybrid material were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (https://www.google.com.tr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&uact=8&ved=0CCsQFjAC&url=http%3A%2F%2Fwww.intertek.com%2Fanalytical-laboratories%2Fxrd%2F&ei=-5WZVYSCHISz7Aatqq-IAw&usg=AFQjCNFBlk-9wqy49foh8tskmbD-GGbG9g&sig2=eKrhYjO75rl_Id2sLGpq4w&bvm=bv.96952980,d.bGg) (XRD), X-ray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS), and Brunauer-Emmett-Teller (BET) analyses. The analyses showed that CuO nanoparticles are well-distributed on the activated carbon surface. The CO2 adsorption behavior of the activated carbon-supported CuO nanoparticles was observed by thermogravimetric analysis (TGA), temperature programmed desorption (TPD), Fourier transform infrared (FTIR), and BET analyses. The results showed that CuO nanoparticle loading on activated carbon led to about 70% increase in CO2 adsorption capacity of activated carbon under standard conditions (1 atm and 298 K). The main contributor to the observed increase is an improvement in chemical adsorption of CO2 due to the presence of CuO nanoparticles on activated carbon.

  11. Mechanical Properties of Graphene Nanoplatelet/Carbon Fiber/Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, C. M.; Klimek-McDonald, D. R.; Pineda, E. J.; King, J. A.; Reichanadter, A. M.; Miskioglu, I.; Gowtham, S.; Odegard, G. M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  12. Mechanical Properties of Graphene Nanoplatelet Carbon Fiber Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, Cameron M.; Klimek-McDonald, Danielle R.; Pineda, Evan J.; King, Julie A.; Reichanadter, Alex M.; Miskioglu, Ibrahim; Gowtham, S.; Odegard, Gregory M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  13. Structure and morphology controllable synthesis of Ag/carbon hybrid with ionic liquid as soft-template and their catalytic properties

    International Nuclear Information System (INIS)

    Wu Shuying; Ding Yunsheng; Zhang Xiaomin; Tang Haiou; Chen Long; Li Boxuan

    2008-01-01

    Ag/carbon hybrids were fabricated by the redox of glucose and silver nitrate (AgNO 3 ) in the presence of imidazolium ionic liquid ([C 14 mim]BF 4 ) under hydrothermal condition. Monodisperse carbon hollow sub-microspheres encapsulating Ag nanoparticles and Ag/carbon cables were selectively prepared by varying the concentration of ionic liquid. Other reaction parameters, such as reaction temperature, reaction time and the mole ratio of silver nitrate to glucose, play important roles in controlling the structures of the products. The products were characterized by XRD, TEM (HRTEM), SEM, energy-dispersive X-ray spectroscopy (EDX), FTIR spectroscopy and a Raman spectrometer. The possible formation mechanism was proposed. The catalytic property of the hybrid in the oxidation of 1-butanol by H 2 O 2 was also investigated. - Graphical abstract: Monodisperse carbon hollow nanospheres encapsulating Ag nanoparticles and Ag/carbon nanocables were selectively prepared with ionic liquids as the soft-template. The controllable synthesis of Ag/C nano-hybrids was realized by varying the concentration of ionic liquids, reaction temperature, reaction time and the mole ratio of silver nitrate to glucose. The catalysis of Ag/C nano-hybrid in the oxidation of 1-butanol by H 2 O 2 was also investigated

  14. Large-scale complementary macroelectronics using hybrid integration of carbon nanotubes and IGZO thin-film transistors.

    Science.gov (United States)

    Chen, Haitian; Cao, Yu; Zhang, Jialu; Zhou, Chongwu

    2014-06-13

    Carbon nanotubes and metal oxide semiconductors have emerged as important materials for p-type and n-type thin-film transistors, respectively; however, realizing sophisticated macroelectronics operating in complementary mode has been challenging due to the difficulty in making n-type carbon nanotube transistors and p-type metal oxide transistors. Here we report a hybrid integration of p-type carbon nanotube and n-type indium-gallium-zinc-oxide thin-film transistors to achieve large-scale (>1,000 transistors for 501-stage ring oscillators) complementary macroelectronic circuits on both rigid and flexible substrates. This approach of hybrid integration allows us to combine the strength of p-type carbon nanotube and n-type indium-gallium-zinc-oxide thin-film transistors, and offers high device yield and low device variation. Based on this approach, we report the successful demonstration of various logic gates (inverter, NAND and NOR gates), ring oscillators (from 51 stages to 501 stages) and dynamic logic circuits (dynamic inverter, NAND and NOR gates).

  15. Constraining climate sensitivity and continental versus seafloor weathering using an inverse geological carbon cycle model.

    Science.gov (United States)

    Krissansen-Totton, Joshua; Catling, David C

    2017-05-22

    The relative influences of tectonics, continental weathering and seafloor weathering in controlling the geological carbon cycle are unknown. Here we develop a new carbon cycle model that explicitly captures the kinetics of seafloor weathering to investigate carbon fluxes and the evolution of atmospheric CO 2 and ocean pH since 100 Myr ago. We compare model outputs to proxy data, and rigorously constrain model parameters using Bayesian inverse methods. Assuming our forward model is an accurate representation of the carbon cycle, to fit proxies the temperature dependence of continental weathering must be weaker than commonly assumed. We find that 15-31 °C (1σ) surface warming is required to double the continental weathering flux, versus 3-10 °C in previous work. In addition, continental weatherability has increased 1.7-3.3 times since 100 Myr ago, demanding explanation by uplift and sea-level changes. The average Earth system climate sensitivity is  K (1σ) per CO 2 doubling, which is notably higher than fast-feedback estimates. These conclusions are robust to assumptions about outgassing, modern fluxes and seafloor weathering kinetics.

  16. Self-Assembled CNT-Polymer Hybrids in Single-Walled Carbon Nanotubes Dispersed Aqueous Triblock Copolymer Solutions

    Science.gov (United States)

    Vijayaraghavan, D.; Manjunatha, A. S.; Poojitha, C. G.

    2018-04-01

    We have carried out scanning electron microscopy (SEM), differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS), electrical conductivity, and 1H NMR studies as a function of temperature on single-walled carbon nanotubes (SWCNTs) dispersed aqueous triblock copolymer (P123) solutions. The single-walled carbon nanotubes in this system aggregate to form bundles, and the bundles aggregate to form net-like structures. Depending on the temperature and phases of the polymer, this system exhibits three different self-assembled CNT-polymer hybrids. We find CNT-unimer hybrid at low temperatures, CNT-micelle hybrid at intermediate temperatures wherein the polymer micelles are adsorbed in the pores of the CNT nets, and another type of CNT-micelle hybrid at high temperatures wherein the polymer micelles are adsorbed on the surface of the CNT bundles. Our DSC thermogram showed two peaks related to these structural changes in the CNT-polymer hybrids. Temperature dependence of the 1H NMR chemical shifts of the molecular groups of the polymer and the AC electrical conductivity of the composite also showed discontinuous changes at the temperatures at which the CNT-polymer hybrid's structural changes are seen. Interestingly, for a higher CNT concentration (0.5 wt.%) in the system, the aggregated polymer micelles adsorbed on the CNTs exhibit cone-like and cube-like morphologies at the intermediate and at high temperatures respectively.

  17. Textile electrodes woven by carbon nanotube-graphene hybrid fibers for flexible electrochemical capacitors.

    Science.gov (United States)

    Cheng, Huhu; Dong, Zelin; Hu, Chuangang; Zhao, Yang; Hu, Yue; Qu, Liangti; Chen, Nan; Dai, Liming

    2013-04-21

    Functional graphene-based fibers are promising as new types of flexible building blocks for the construction of wearable architectures and devices. Unique one-dimensional (1D) carbon nanotubes (CNTs) and 2D graphene (CNT/G) hybrid fibers with a large surface area and high electrical conductivity have been achieved by pre-intercalating graphene fibers with Fe3O4 nanoparticles for subsequent CVD growth of CNTs. The CNT/G hybrid fibers can be further woven into textile electrodes for the construction of flexible supercapacitors with a high tolerance to the repeated bending cycles. Various other applications, such as catalysis, separation, and adsorption, can be envisioned for the CNT/G hybrid fibers.

  18. Torn Between Two Worlds: Hybridity and In-between Identity Recognition in Goli Taraqqi’s Two Worlds

    Directory of Open Access Journals (Sweden)

    Nasser Najafi Shabankare

    2014-10-01

    Full Text Available As one of the contemporary Iranian women writers living in the U.S, Goli Taraqqi’s fiction is mostly concerned with pains and difficulties of migrant Iranian women in other countries. Bearing a biographical resemblance, her sequence collection to Scattered Memories, entitled Two Worlds retells interrelated short stories of a woman writer narrator, entangled in an asylum in Paris, who digs into her past, writes stories about it, and is able to regain her sanity in the end, as she gets ready to enter the brave new world. The process of identity recognition is to be approached with an eye on Homi K, Bhabha’s assertions about ‘hybridity’ and ‘in-between’ as explained in his 1994 Location and Culture, to see to what degree the newly gained identity, which is resembled to a resurrection, is in fact a hybrid one.

  19. Optical and thermal response of single-walled carbon nanotube–copper sulfide nanoparticle hybrid nanomaterials

    International Nuclear Information System (INIS)

    Tseng, Yi-Hsuan; He Yuan; Que Long; Lakshmanan, Santana; Yang Chang; Chen Wei

    2012-01-01

    This paper reports the optical and thermal response of a single-walled carbon nanotube–copper sulfide nanoparticle (SWNT–CuS NP) hybrid nanomaterial and its application as a thermoelectric generator. The hybrid nanomaterial was synthesized using oleylamine molecules as the linker molecules between SWNTs and CuS NPs. Measurements found that the hybrid nanomaterial has significantly increased light absorption (up to 80%) compared to the pure SWNT. Measurements also found that the hybrid nanomaterial thin-film devices exhibit a clear optical and thermal switching effect, which can be further enhanced up to 10 × by asymmetric illumination of light and thermal radiation on the thin-film devices instead of symmetric illumination. A simple prototype thermoelectric generator enabled by the hybrid nanomaterials is demonstrated, indicating a new route for achieving thermoelectricity. (paper)

  20. Comparison of hybrid and baseline ELMy H-mode confinement in JET with the carbon wall

    NARCIS (Netherlands)

    Beurskens, M. N. A.; Frassinetti, L.; Challis, C.; Osborne, T.; Snyder, P. B.; Alper, B.; Angioni, C.; Bourdelle, C.; Buratti, P.; Crisanti, F.; Giovannozzi, E.; Giroud, C.; Groebner, R.; Hobirk, J.; Jenkins, I.; Joffrin, E.; Leyland, M. J.; Lomas, P.; Mantica, P.; McDonald, D.; Nunes, I.; Rimini, F.; Saarelma, S.; Voitsekhovitch, I.; P. de Vries,; Zarzoso, D.

    2013-01-01

    The confinement in JET baseline type I ELMy H-mode plasmas is compared to that in so-called hybrid H-modes in a database study of 112 plasmas in JET with the carbon fibre composite (CFC) wall. The baseline plasmas typically have beta(Nu) similar to 1.5-2, H-98 similar to 1, whereas the hybrid

  1. 3D Hollow Sn@Carbon-Graphene Hybrid Material as Promising Anode for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Xiaoyu Zheng

    2014-01-01

    Full Text Available A 3D hollow Sn@C-graphene hybrid material (HSCG with high capacity and excellent cyclic and rate performance is fabricated by a one-pot assembly method. Due to the fast electron and ion transfer as well as the efficient carbon buffer structure, the hybrid material is promising in high-performance lithium-ion battery.

  2. Synthesis and properties of core–shell fluorescent hybrids with distinct morphologies based on carbon dots

    KAUST Repository

    Markova, Zdenka; Bourlinos, Athanasios B.; Safarova, Klara; Polakova, Katerina; Tucek, Jiri; Medrik, Ivo; Siskova, Karolina; Petr, Jan; Krysmann, Marta; Giannelis, Emmanuel P.; Zboril, Radek

    2012-01-01

    Fluorescent core-shell nanohybrids with the shells derived from carbon dots and cores differing in the chemical nature and morphology were synthesized. Hybrid nanoparticles combine fluorescence with other functionalities such as magnetic response on a single platform. These hybrids can be used in various bioapplications as demonstrated with labeling of stem cells. © The Royal Society of Chemistry 2012.

  3. Polyetheretherketone Hybrid Composites with Bioactive Nanohydroxyapatite and Multiwalled Carbon Nanotube Fillers

    Directory of Open Access Journals (Sweden)

    Chen Liu

    2016-12-01

    Full Text Available Polyetheretherketone (PEEK hybrid composites reinforced with inorganic nanohydroxyapatite (nHA and multiwalled carbon nanotube (MWNT were prepared by melt-compounding and injection molding processes. The additions of nHA and MWNT to PEEK were aimed to increase its elastic modulus, tensile strength, and biocompatibility, rendering the hybrids suitable for load-bearing implant applications. The structural behavior, mechanical property, wettability, osteoblastic cell adhesion, proliferation, differentiation, and mineralization of the PEEK/nHA-MWNT hybrids were studied. X-ray diffraction and SEM observation showed that both nHA and MWNT fillers are incorporated into the polymer matrix of PEEK-based hybrids. Tensile tests indicated that the elastic modulus of PEEK can be increased from 3.87 to 7.13 GPa by adding 15 vol % nHA and 1.88 vol % MWNT fillers. The tensile strength and elongation at break of the PEEK/(15% nHA-(1.88% MWNT hybrid were 64.48 MPa and 1.74%, respectively. Thus the tensile properties of this hybrid were superior to those of human cortical bones. Water contact angle measurements revealed that the PEEK/(15% nHA-(1.88% MWNT hybrid is hydrophilic due to the presence of nHA. Accordingly, hydrophilic PEEK/(15% nHA-(1.88% MWNT hybrid promoted the adhesion, proliferation, differentiation, and mineralization of murine MC3T3-E1 osteoblasts on its surface effectively on the basis of cell culture, fluorescence microscopy, MTT assay, WST-1 assay, alkaline phosphatase activity, and Alizarin red staining tests. Thus the PEEK/(15% nHA-(1.88% MWNT hybrid has the potential to be used for fabricating load-bearing bone implants.

  4. Land-use and land-cover change carbon emissions between 1901 and 2012 constrained by biomass observations

    Directory of Open Access Journals (Sweden)

    W. Li

    2017-11-01

    Full Text Available The use of dynamic global vegetation models (DGVMs to estimate CO2 emissions from land-use and land-cover change (LULCC offers a new window to account for spatial and temporal details of emissions and for ecosystem processes affected by LULCC. One drawback of LULCC emissions from DGVMs, however, is lack of observation constraint. Here, we propose a new method of using satellite- and inventory-based biomass observations to constrain historical cumulative LULCC emissions (ELUCc from an ensemble of nine DGVMs based on emerging relationships between simulated vegetation biomass and ELUCc. This method is applicable on the global and regional scale. The original DGVM estimates of ELUCc range from 94 to 273 PgC during 1901–2012. After constraining by current biomass observations, we derive a best estimate of 155 ± 50 PgC (1σ Gaussian error. The constrained LULCC emissions are higher than prior DGVM values in tropical regions but significantly lower in North America. Our emergent constraint approach independently verifies the median model estimate by biomass observations, giving support to the use of this estimate in carbon budget assessments. The uncertainty in the constrained ELUCc is still relatively large because of the uncertainty in the biomass observations, and thus reduced uncertainty in addition to increased accuracy in biomass observations in the future will help improve the constraint. This constraint method can also be applied to evaluate the impact of land-based mitigation activities.

  5. Carbon Nanofiber/3D Nanoporous Silicon Hybrids as High Capacity Lithium Storage Materials.

    Science.gov (United States)

    Park, Hyeong-Il; Sohn, Myungbeom; Kim, Dae Sik; Park, Cheolho; Choi, Jeong-Hee; Kim, Hansu

    2016-04-21

    Carbon nanofiber (CNF)/3D nanoporous (3DNP) Si hybrid materials were prepared by chemical etching of melt-spun Si/Al-Cu-Fe alloy nanocomposites, followed by carbonization using a pitch. CNFs were successfully grown on the surface of 3DNP Si particles using residual Fe impurities after acidic etching, which acted as a catalyst for the growth of CNFs. The resulting CNF/3DNP Si hybrid materials showed an enhanced cycle performance up to 100 cycles compared to that of the pristine Si/Al-Cu-Fe alloy nanocomposite as well as that of bare 3DNP Si particles. These results indicate that CNFs and the carbon coating layer have a beneficial effect on the capacity retention characteristics of 3DNP Si particles by providing continuous electron-conduction pathways in the electrode during cycling. The approach presented here provides another way to improve the electrochemical performances of porous Si-based high capacity anode materials for lithium-ion batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Computational modeling of electrically conductive networks formed by graphene nanoplatelet-carbon nanotube hybrid particles

    KAUST Repository

    Mora Cordova, Angel

    2018-01-30

    One strategy to ensure that nanofiller networks in a polymer composite percolate at low volume fractions is to promote segregation. In a segregated structure, the concentration of nanofillers is kept low in some regions of the sample. In turn, the concentration in remaining regions is much higher than the average concentration of the sample. This selective placement of the nanofillers ensures percolation at low average concentration. One original strategy to promote segregation is by tuning the shape of the nanofillers. We use a computational approach to study the conductive networks formed by hybrid particles obtained by growing carbon nanotubes (CNTs) on graphene nanoplatelets (GNPs). The objective of this study is (1) to show that the higher electrical conductivity of these composites is due to the hybrid particles forming a segregated structure and (2) to understand which parameters defining the hybrid particles determine the efficiency of the segregation. We construct a microstructure to observe the conducting paths and determine whether a segregated structure has indeed been formed inside the composite. A measure of efficiency is presented based on the fraction of nanofillers that contribute to the conductive network. Then, the efficiency of the hybrid-particle networks is compared to those of three other networks of carbon-based nanofillers in which no hybrid particles are used: only CNTs, only GNPs, and a mix of CNTs and GNPs. Finally, some parameters of the hybrid particle are studied: the CNT density on the GNPs, and the CNT and GNP geometries. We also present recommendations for the further improvement of a composite\\'s conductivity based on these parameters.

  7. Computational modeling of electrically conductive networks formed by graphene nanoplatelet-carbon nanotube hybrid particles

    KAUST Repository

    Mora Cordova, Angel; Han, Fei; Lubineau, Gilles

    2018-01-01

    One strategy to ensure that nanofiller networks in a polymer composite percolate at low volume fractions is to promote segregation. In a segregated structure, the concentration of nanofillers is kept low in some regions of the sample. In turn, the concentration in remaining regions is much higher than the average concentration of the sample. This selective placement of the nanofillers ensures percolation at low average concentration. One original strategy to promote segregation is by tuning the shape of the nanofillers. We use a computational approach to study the conductive networks formed by hybrid particles obtained by growing carbon nanotubes (CNTs) on graphene nanoplatelets (GNPs). The objective of this study is (1) to show that the higher electrical conductivity of these composites is due to the hybrid particles forming a segregated structure and (2) to understand which parameters defining the hybrid particles determine the efficiency of the segregation. We construct a microstructure to observe the conducting paths and determine whether a segregated structure has indeed been formed inside the composite. A measure of efficiency is presented based on the fraction of nanofillers that contribute to the conductive network. Then, the efficiency of the hybrid-particle networks is compared to those of three other networks of carbon-based nanofillers in which no hybrid particles are used: only CNTs, only GNPs, and a mix of CNTs and GNPs. Finally, some parameters of the hybrid particle are studied: the CNT density on the GNPs, and the CNT and GNP geometries. We also present recommendations for the further improvement of a composite's conductivity based on these parameters.

  8. A HYBRID HEURISTIC ALGORITHM FOR SOLVING THE RESOURCE CONSTRAINED PROJECT SCHEDULING PROBLEM (RCPSP

    Directory of Open Access Journals (Sweden)

    Juan Carlos Rivera

    Full Text Available The Resource Constrained Project Scheduling Problem (RCPSP is a problem of great interest for the scientific community because it belongs to the class of NP-Hard problems and no methods are known that can solve it accurately in polynomial processing times. For this reason heuristic methods are used to solve it in an efficient way though there is no guarantee that an optimal solution can be obtained. This research presents a hybrid heuristic search algorithm to solve the RCPSP efficiently, combining elements of the heuristic Greedy Randomized Adaptive Search Procedure (GRASP, Scatter Search and Justification. The efficiency obtained is measured taking into account the presence of the new elements added to the GRASP algorithm taken as base: Justification and Scatter Search. The algorithms are evaluated using three data bases of instances of the problem: 480 instances of 30 activities, 480 of 60, and 600 of 120 activities respectively, taken from the library PSPLIB available online. The solutions obtained by the developed algorithm for the instances of 30, 60 and 120 are compared with results obtained by other researchers at international level, where a prominent place is obtained, according to Chen (2011.

  9. Improved helicopter aeromechanical stability analysis using segmented constrained layer damping and hybrid optimization

    Science.gov (United States)

    Liu, Qiang; Chattopadhyay, Aditi

    2000-06-01

    Aeromechanical stability plays a critical role in helicopter design and lead-lag damping is crucial to this design. In this paper, the use of segmented constrained damping layer (SCL) treatment and composite tailoring is investigated for improved rotor aeromechanical stability using formal optimization technique. The principal load-carrying member in the rotor blade is represented by a composite box beam, of arbitrary thickness, with surface bonded SCLs. A comprehensive theory is used to model the smart box beam. A ground resonance analysis model and an air resonance analysis model are implemented in the rotor blade built around the composite box beam with SCLs. The Pitt-Peters dynamic inflow model is used in air resonance analysis under hover condition. A hybrid optimization technique is used to investigate the optimum design of the composite box beam with surface bonded SCLs for improved damping characteristics. Parameters such as stacking sequence of the composite laminates and placement of SCLs are used as design variables. Detailed numerical studies are presented for aeromechanical stability analysis. It is shown that optimum blade design yields significant increase in rotor lead-lag regressive modal damping compared to the initial system.

  10. The Best of Both Worlds: Developing a Hybrid Data System for the ASF DAAC

    Science.gov (United States)

    Arko, S. A.; Buechler, B.; Wolf, V. G.

    2017-12-01

    The Alaska Satellite Facility (ASF) at the University of Alaska Fairbanks hosts the NASA Distributed Active Archive Center (DAAC) specializing in synthetic aperture radar (SAR). Historically, the ASF DAAC has hosted hardware on-premises and developed DAAC-specific software to operate, manage, and maintain the DAAC data system. In the past year, ASF DAAC has been moving many of the standard DAAC operations into the Amazon Web Services (AWS) cloud. This includes data ingest, basic pre-processing, archiving, and distribution within the AWS environment. While the cloud offers nearly unbounded capacity for expansion and a great host of services, there also can be unexpected and unplanned costs for such. Additionally, these costs can be difficult to forecast even with historic data usage patterns and models for future usage. In an effort to maximize the effectiveness of the DAAC data system, while still managing and accurately forecasting costs, ASF DAAC has developed a hybrid, cloud and on-premises, data system. The goal of this project is to make extensive use of the AWS cloud, and when appropriate, utilize on-premises resources to help constrain costs. This hybrid system attempts to mimic, on premises, a cloud environment using Kubernetes container orchestration in order that software can be run in either location with little change. Combined with hybrid data storage architecture, the new data system makes use of the great capacity of the cloud while maintaining an on-premises options. This presentation will describe the development of the hybrid data system, including the micro-services architecture and design, the container orchestration, and hybrid storage. Additional we will highlight the lessons learned through the development process, cost forecasting for current and future SAR-mission operations, and provide a discussion of the pros and cons of hybrid architectures versus all-cloud deployments. This development effort has led to a system that is capable and

  11. Thermal-based modeling of coupled carbon, water, and energy fluxes using nominal light use efficiencies constrained by leaf chlorophyll observations

    KAUST Repository

    Schull, M. A.

    2015-03-11

    Recent studies have shown that estimates of leaf chlorophyll content (Chl), defined as the combined mass of chlorophyll a and chlorophyll b per unit leaf area, can be useful for constraining estimates of canopy light use efficiency (LUE). Canopy LUE describes the amount of carbon assimilated by a vegetative canopy for a given amount of absorbed photosynthetically active radiation (APAR) and is a key parameter for modeling land-surface carbon fluxes. A carbon-enabled version of the remote-sensing-based two-source energy balance (TSEB) model simulates coupled canopy transpiration and carbon assimilation using an analytical sub-model of canopy resistance constrained by inputs of nominal LUE (βn), which is modulated within the model in response to varying conditions in light, humidity, ambient CO2 concentration, and temperature. Soil moisture constraints on water and carbon exchange are conveyed to the TSEB-LUE indirectly through thermal infrared measurements of land-surface temperature. We investigate the capability of using Chl estimates for capturing seasonal trends in the canopy βn from in situ measurements of Chl acquired in irrigated and rain-fed fields of soybean and maize near Mead, Nebraska. The results show that field-measured Chl is nonlinearly related to βn, with variability primarily related to phenological changes during early growth and senescence. Utilizing seasonally varying βn inputs based on an empirical relationship with in situ measured Chl resulted in improvements in carbon flux estimates from the TSEB model, while adjusting the partitioning of total water loss between plant transpiration and soil evaporation. The observed Chl-βn relationship provides a functional mechanism for integrating remotely sensed Chl into the TSEB model, with the potential for improved mapping of coupled carbon, water, and energy fluxes across vegetated landscapes.

  12. Continuation of Sets of Constrained Orbit Segments

    DEFF Research Database (Denmark)

    Schilder, Frank; Brøns, Morten; Chamoun, George Chaouki

    Sets of constrained orbit segments of time continuous flows are collections of trajectories that represent a whole or parts of an invariant set. A non-trivial but simple example is a homoclinic orbit. A typical representation of this set consists of an equilibrium point of the flow and a trajectory...... that starts close and returns close to this fixed point within finite time. More complicated examples are hybrid periodic orbits of piecewise smooth systems or quasi-periodic invariant tori. Even though it is possible to define generalised two-point boundary value problems for computing sets of constrained...... orbit segments, this is very disadvantageous in practice. In this talk we will present an algorithm that allows the efficient continuation of sets of constrained orbit segments together with the solution of the full variational problem....

  13. Poly(3-hexylthiophene)/multiwalled carbon hybrid coaxial nanotubes: nanoscale rectification and photovoltaic characteristics.

    Science.gov (United States)

    Kim, Kihyun; Shin, Ji Won; Lee, Yong Baek; Cho, Mi Yeon; Lee, Suk Ho; Park, Dong Hyuk; Jang, Dong Kyu; Lee, Cheol Jin; Joo, Jinsoo

    2010-07-27

    We fabricate hybrid coaxial nanotubes (NTs) of multiwalled carbon nanotubes (MWCNTs) coated with light-emitting poly(3-hexylthiophene) (P3HT). The p-type P3HT material with a thickness of approximately 20 nm is electrochemically deposited onto the surface of the MWCNT. The formation of hybrid coaxial NTs of the P3HT/MWCNT is confirmed by a transmission electron microscope, FT-IR, and Raman spectra. The optical and structural properties of the hybrid NTs are characterized using ultraviolet and visible absorption, Raman, and photoluminescence (PL) spectra where, it is shown that the PL intensity of the P3HT materials decreases after the hybridization with the MWCNTs. The current-voltage (I-V) characteristics of the outer P3HT single NT show the semiconducting behavior, while ohmic behavior is observed for the inner single MWCNT. The I-V characteristics of the hybrid junction between the outer P3HT NT and the inner MWCNT, for the hybrid single NT, exhibit the characteristics of a diode (i.e., rectification), whose efficiency is clearly enhanced with light irradiation. The rectification effect of the hybrid single NT has been analyzed in terms of charge tunneling models. The quasi-photovoltaic effect is also observed at low bias for the P3HT/MWCNT hybrid single NT.

  14. Dechlorination of Environmental Contaminants Using a Hybrid Nanocatalyst: Palladium Nanoparticles Supported on Hierarchical Carbon Nanostructures

    Directory of Open Access Journals (Sweden)

    Hema Vijwani

    2012-01-01

    Full Text Available This paper demonstrates the effectiveness of a new type of hybrid nanocatalyst material that combines the high surface area of nanoparticles and nanotubes with the structural robustness and ease of handling larger supports. The hybrid material is made by fabricating palladium nanoparticles on two types of carbon supports: as-received microcellular foam (Foam and foam with carbon nanotubes anchored on the pore walls (CNT/Foam. Catalytic reductive dechlorination of carbon tetrachloride with these materials has been investigated using gas chromatography. It is seen that while both palladium-functionalized carbon supports are highly effective in the degradation of carbon tetrachloride, the rate of degradation is significantly increased with palladium on CNT/Foam. However, there is scope to increase this rate further if the wettability of these structures can be enhanced in the future. Microstructural and spectroscopic analyses of the fresh and used catalysts have been compared which indicates that there is no change in density or surface chemical states of the catalyst after prolonged use in dechlorination test. This implies that these materials can be used repeatedly and hence provide a simple, powerful, and cost-effective approach for dechlorination of water.

  15. Effect of hybrid system battery performance on determining CO2 emissions of hybrid electric vehicles in real-world conditions

    International Nuclear Information System (INIS)

    Alvarez, Robert; Schlienger, Peter; Weilenmann, Martin

    2010-01-01

    Hybrid electric vehicles (HEVs) can potentially reduce vehicle CO 2 emissions by using recuperated kinetic vehicle energy stored as electric energy in a hybrid system battery (HSB). HSB performance affects the individual net HEV CO 2 emissions for a given driving pattern, which is considered to be equivalent to unchanged net energy content in the HSB. The present study investigates the influence of HSB performance on the statutory correction procedure used to determine HEV CO 2 emissions in Europe based on chassis dynamometer measurements with three identical in-use examples of a full HEV model featuring different mileages. Statutory and real-world driving cycles and full electric vehicle operation modes have been considered. The main observation is that the selected HEVs can only use 67-80% of the charge provided to the HSB, which distorts the outcomes of the statutory correction procedure that does not consider such irreversibility. CO 2 emissions corrected according to this procedure underestimate the true net CO 2 emissions of one HEV by approximately 13% in real-world urban driving. The correct CO 2 emissions are only reproduced when considering the HSB performance in this driving pattern. The statutory procedure for correcting HEV CO 2 emissions should, therefore, be adapted.

  16. Continuous In-situ Measurements of Carbonyl Sulfide (OCS) and Carbon Dioxide Isotopes to Constrain Ecosystem Carbon and Water Exchanges

    Science.gov (United States)

    Rastogi, B.; Still, C. J.; Noone, D. C.; Berkelhammer, M. B.; Whelan, M.; Lai, C. T.; Hollinger, D. Y.; Gupta, M.; Leen, J. B.; Huang, Y. W.

    2015-12-01

    Understanding the processes that control the terrestrial exchange of carbon and water are critical for examining the role of forested ecosystems in changing climates. A small but increasing number of studies have identified Carbonyl Sulfide (OCS) as a potential tracer for photosynthesis. OCS is hydrolyzed by an irreversible reaction in leaf mesophyll cells that is catalyzed by the enzyme, carbonic anhydrase. Leaf- level field and greenhouse studies indicate that OCS uptake is controlled by stomatal activity and that the ratio of OCS and CO2 uptake is reasonably constant. Existing studies on ecosystem OCS exchange have been based on laboratory measurements or short field campaigns and therefore little information on OCS exchange in a natural ecosystem over longer timescales is available. The objective of this study is to further assess the stability of OCS as a tracer for canopy photosynthesis in an active forested ecosystem and also to assess its utility for constraining transpiration, since both fluxes are mediated by canopy stomatal conductance. An off-axis integrated cavity output spectroscopy analyzer (Los Gatos Research Inc.) was deployed at the Wind River Experimental Forest in Washington (45.8205°N, 121.9519°W). Canopy air was sampled from four heights as well as the soil to measure vertical gradients of OCS within the canopy, and OCS exchange between the forest and the atmosphere for the growing season. Here we take advantage of simultaneous measurements of the stable isotopologues of H2O and CO2 at corresponding heights as well as NEE (Net Ecosystem Exchange) from eddy covariance measurements to compare GPP (Gross Primary Production) and transpiration estimates from a variety of independent techniques. Our findings also seek to allow assessment of the environmental and ecophysicological controls on evapotranspiration rates, which are projected to change in coming decades, and are otherwise poorly constrained.

  17. Carbon Nano-Allotrope/Magnetic Nanoparticle Hybrid Nanomaterials as T2 Contrast Agents for Magnetic Resonance Imaging Applications

    Directory of Open Access Journals (Sweden)

    Yunxiang Gao

    2018-02-01

    Full Text Available Magnetic resonance imaging (MRI is the most powerful tool for deep penetration and high-quality 3D imaging of tissues with anatomical details. However, the sensitivity of the MRI technique is not as good as that of the radioactive or optical imaging methods. Carbon-based nanomaterials have attracted significant attention in biomaterial research in recent decades due to their unique physical properties, versatile functionalization chemistry, as well as excellent biological compatibility. Researchers have employed various carbon nano-allotropes to develop hybrid MRI contrast agents for improved sensitivity. This review summarizes the new research progresses in carbon-based hybrid MRI contrast agents, especially those reported in the past five years. The review will only focus on T2-weighted MRI agents and will be categorized by the different carbon allotrope types and magnetic components. Considering the strong trend in recent bio-nanotechnology research towards multifunctional diagnosis and therapy, carbon-based MRI contrast agents integrated with other imaging modalities or therapeutic functions are also covered.

  18. Diamond-like carbon films deposited by a hybrid ECRCVD system

    International Nuclear Information System (INIS)

    Guo, C.T.; Dittrich, K.-H.

    2007-01-01

    A novel hybrid technique for diamond-like carbon (DLC) film deposition has been developed. This technique combines the electron cyclotron resonance chemical vapor deposition (ECRCVD) of C 2 H 2 and metallic magnetron sputtering. Here we described how DLC film is used for a variety of applications such as stamper, PCB micro-tools, and threading form-tools by taking advantage of hybrid ECRCVD system. The structure of the DLC films is delineated by a function of bias voltages by Raman spectroscopy. This function includes parameters such as dependence of G peak positions and the intensity ratio (I D /I G ). Atomic force microscope (AFM) examines the root-mean-square (R.M.S.) roughness and the surface morphology. Excellent adhesion and lower friction coefficients of a DLC film were also assessed

  19. Quantitative evaluation of orbital hybridization in carbon nanotubes under radial deformation using π-orbital axis vector

    Directory of Open Access Journals (Sweden)

    Masato Ohnishi

    2015-04-01

    Full Text Available When a radial strain is applied to a carbon nanotube (CNT, the increase in local curvature induces orbital hybridization. The effect of the curvature-induced orbital hybridization on the electronic properties of CNTs, however, has not been evaluated quantitatively. In this study, the strength of orbital hybridization in CNTs under homogeneous radial strain was evaluated quantitatively. Our analyses revealed the detailed procedure of the change in electronic structure of CNTs. In addition, the dihedral angle, the angle between π-orbital axis vectors of adjacent atoms, was found to effectively predict the strength of local orbital hybridization in deformed CNTs.

  20. Computational modeling of electrically conductive networks formed by graphene nanoplatelet-carbon nanotube hybrid particles

    Science.gov (United States)

    Mora, A.; Han, F.; Lubineau, G.

    2018-04-01

    One strategy to ensure that nanofiller networks in a polymer composite percolate at low volume fractions is to promote segregation. In a segregated structure, the concentration of nanofillers is kept low in some regions of the sample. In turn, the concentration in the remaining regions is much higher than the average concentration of the sample. This selective placement of the nanofillers ensures percolation at low average concentration. One original strategy to promote segregation is by tuning the shape of the nanofillers. We use a computational approach to study the conductive networks formed by hybrid particles obtained by growing carbon nanotubes (CNTs) on graphene nanoplatelets (GNPs). The objective of this study is (1) to show that the higher electrical conductivity of these composites is due to the hybrid particles forming a segregated structure and (2) to understand which parameters defining the hybrid particles determine the efficiency of the segregation. We construct a microstructure to observe the conducting paths and determine whether a segregated structure has indeed been formed inside the composite. A measure of efficiency is presented based on the fraction of nanofillers that contribute to the conductive network. Then, the efficiency of the hybrid-particle networks is compared to those of three other networks of carbon-based nanofillers in which no hybrid particles are used: only CNTs, only GNPs, and a mix of CNTs and GNPs. Finally, some parameters of the hybrid particle are studied: the CNT density on the GNPs, and the CNT and GNP geometries. We also present recommendations for the further improvement of a composite’s conductivity based on these parameters.

  1. Synthesis of palladium nanoparticle modified reduced graphene oxide and multi-walled carbon nanotube hybrid structures for electrochemical applications

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jie, E-mail: hujie@tyut.edu.cn [Micro and Nano System Research Center, Key Lab of Advanced Transducers and Intelligent Control System (Ministry of Education) & College of Information Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi (China); Zhao, Zhenting; Zhang, Jun; Li, Gang; Li, Pengwei; Zhang, Wendong [Micro and Nano System Research Center, Key Lab of Advanced Transducers and Intelligent Control System (Ministry of Education) & College of Information Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi (China); Lian, Kun, E-mail: liankun@tyut.edu.cn [Micro and Nano System Research Center, Key Lab of Advanced Transducers and Intelligent Control System (Ministry of Education) & College of Information Engineering, Taiyuan University of Technology, Taiyuan, 030024, Shanxi (China); School of Nano-Science and Nano-Engineering, Suzhou & Collaborative Innovation Center of Suzhou Nano Science and Technology, Xi' an Jiaotong University, Xi' an, 710049 (China); Center for Advanced Microstructures and Devices, Louisiana State University, LA, 70806 (United States)

    2017-02-28

    Graphical abstract: A sensitive hydrazine electrochemical sensor was fabricated by using palladium (Pd) nanoparticle functionalized reduced graphene oxide (rGO) and multi-walled carbon nanotube (MWCNTs) hybrid structures (Pd/rGO-MWCNTs). - Highlights: • rGO-MWCNTs hybrid structures and Pd nanoparticles are prepared using electrochemical methods. • rGO-MWCNTs hybrid films are used as supports and co-catalysts for Pd nanoparticles. • The Pd/rGO-MWCNTs hybrid structure based sensor shows an ultra-high sensitivity of 7.09 μA μM{sup −1} cm{sup −2} and a low detection limit of 0.15 μM. • The proposed electrochemical sensor exhibits excellent selectivity. - Abstract: In this work, palladium (Pd) nanoparticles functionalized reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) hybrid structures (Pd/rGO-MWCNTs) were successfully prepared by a combination of electrochemical reduction with electrodeposition method. The morphology, structure, and composition of the Pd/rGO-MWCNTs hybrid were characterized by scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy. The as-synthesized hybrid structures were modified on the glassy carbon electrode (GCE) and further utilized for hydrazine sensing. Electrochemical impedance spectroscopic, cyclic voltammetry and single-potential amperometry experiments were carried out on Pd/rGO-MWCNTs hybrid structures to investigate the interface properties and sensing performance. The measured results demonstrate that the fabricated Pd/rGO-MWCNTs/GCE sensor show a high sensitivity of 7.09 μA μM{sup −1} cm{sup −2} in a large concentration range of 1.0 to 1100 μM and a low detection limit of 0.15 μM. Moreover, the as-prepared sensor exhibits good selectivity and stability for the determination of hydrazine under interference conditions.

  2. Synthesis of palladium nanoparticle modified reduced graphene oxide and multi-walled carbon nanotube hybrid structures for electrochemical applications

    International Nuclear Information System (INIS)

    Hu, Jie; Zhao, Zhenting; Zhang, Jun; Li, Gang; Li, Pengwei; Zhang, Wendong; Lian, Kun

    2017-01-01

    Graphical abstract: A sensitive hydrazine electrochemical sensor was fabricated by using palladium (Pd) nanoparticle functionalized reduced graphene oxide (rGO) and multi-walled carbon nanotube (MWCNTs) hybrid structures (Pd/rGO-MWCNTs). - Highlights: • rGO-MWCNTs hybrid structures and Pd nanoparticles are prepared using electrochemical methods. • rGO-MWCNTs hybrid films are used as supports and co-catalysts for Pd nanoparticles. • The Pd/rGO-MWCNTs hybrid structure based sensor shows an ultra-high sensitivity of 7.09 μA μM"−"1 cm"−"2 and a low detection limit of 0.15 μM. • The proposed electrochemical sensor exhibits excellent selectivity. - Abstract: In this work, palladium (Pd) nanoparticles functionalized reduced graphene oxide (rGO) and multi-walled carbon nanotubes (MWCNTs) hybrid structures (Pd/rGO-MWCNTs) were successfully prepared by a combination of electrochemical reduction with electrodeposition method. The morphology, structure, and composition of the Pd/rGO-MWCNTs hybrid were characterized by scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy. The as-synthesized hybrid structures were modified on the glassy carbon electrode (GCE) and further utilized for hydrazine sensing. Electrochemical impedance spectroscopic, cyclic voltammetry and single-potential amperometry experiments were carried out on Pd/rGO-MWCNTs hybrid structures to investigate the interface properties and sensing performance. The measured results demonstrate that the fabricated Pd/rGO-MWCNTs/GCE sensor show a high sensitivity of 7.09 μA μM"−"1 cm"−"2 in a large concentration range of 1.0 to 1100 μM and a low detection limit of 0.15 μM. Moreover, the as-prepared sensor exhibits good selectivity and stability for the determination of hydrazine under interference conditions.

  3. Carbon Reduction Strategies Based on an NW Small-World Network with a Progressive Carbon Tax

    Directory of Open Access Journals (Sweden)

    Bin Wu

    2017-09-01

    Full Text Available There is an increasingly urgent need to reduce carbon emissions. Devising effective carbon tax policies has become an important research topic. It is necessary to explore carbon reduction strategies based on the design of carbon tax elements. In this study, we explore the effect of a progressive carbon tax policy on carbon emission reductions using the logical deduction method. We apply experience-weighted attraction learning theory to construct an evolutionary game model for enterprises with different levels of energy consumption in an NW small-world network, and study their strategy choices when faced with a progressive carbon tax policy. The findings suggest that enterprises that adopt other energy consumption strategies gradually transform to a low energy consumption strategy, and that this trend eventually spreads to the entire system. With other conditions unchanged, the rate at which enterprises change to a low energy consumption strategy becomes faster as the discount coefficient, the network externality, and the expected adjustment factor increase. Conversely, the rate of change slows as the cost of converting to a low energy consumption strategy increases.

  4. Role of direct covalent bonding in enhanced heat dissipation property of flexible graphene oxide–carbon nanotube hybrid film

    International Nuclear Information System (INIS)

    Hwang, Yongseon; Kim, Myeongjin; Kim, Jooheon

    2013-01-01

    The thermal conductivity of graphene oxide/multiwalled carbon nanotube (GO/MWCNT) hybrid films with and without covalent bonding is examined in this study. To fabricate chemically bonded GO/MWCNT hybrid films, chlorinated GO and amino-functionalized MWCNTs are bonded covalently. The mixtures of surface modified GO and MWCNT were filtered and then subjected to hot pressing to fabricate stacked films. Examination of these chemically bonded hybrid films reveal that chlorine-doped GO exhibits enhanced electrical properties because it creates hole charge carriers by attracting the electrons in GO towards chlorine. Enhanced electrical conductivity and low sheet resistance are observed also with increasing MWCNT loadings. On comparing the through-plane thermal properties, the chemically bonded hybrid films were found to exhibit higher thermal conductivity than do the physically bonded hybrid films because of the synergetic interaction of functional groups in GO and MWCNTs in the former films. However, excess addition of MWCNTs to the films leads to an increasing phonon scattering density and a decreased thermal conductivity. - Highlights: • Graphene oxide/carbon nanotube (GO/CNT) films are bonded covalently. • GO/CNT hybrid films are prepared through filtering and hot-pressing method. • Chemically bonded hybrid films exhibit enhanced electrical and thermal properties. • Enhanced thermal conductivity is explained according to increasing CNT contents

  5. Secure Hybrid Encryption from Weakened Key Encapsulation

    NARCIS (Netherlands)

    D. Hofheinz (Dennis); E. Kiltz (Eike); A. Menezes

    2007-01-01

    textabstractWe put forward a new paradigm for building hybrid encryption schemes from constrained chosen-ciphertext secure (CCCA) key-encapsulation mechanisms (KEMs) plus authenticated symmetric encryption. Constrained chosen-ciphertext security is a new security notion for KEMs that we propose. It

  6. Poverty eradication in a carbon constrained world

    OpenAIRE

    Hubacek, Klaus; Baiocchi, Giovanni; Feng, Kuishuang; Patwardhan, Anand

    2017-01-01

    The UN Framework Convention on Climate Change aims to keep warming below 2 °C while recognizing developing countries’ right to eradicate extreme poverty. Poverty eradication is also the first of the Sustainable Development Goals. This paper investigates potential consequences for climate targets of achieving poverty eradication. We find that eradicating extreme poverty, i.e., moving people to an income above $1.9 purchasing power parity (PPP) a day, does not jeopardize the climate target even...

  7. Enhancing hybrid direct carbon fuel cell anode performance using Ag2O

    DEFF Research Database (Denmark)

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

    2015-01-01

    A hybrid-direct carbon fuel cell (HDCFC), consisting of a molten slurry of solid carbon black and (Li-K)2CO3 added to the anode chamber of a solid oxide fuel cell, was characterized using current-potential-power density curves, electrochemical impedance spectroscopy, and cyclic voltammetry. Two...... types of experimental setups were employed in this study, an anode-supported full cell configuration (two electrodes, two atmospheres setup) and a 3-electrode electrolyte-supported half-cell setup (single atmosphere). Anode processes with and without catalysts were investigated as a function...... of temperature (700-800 °C) and anode sweep gas (N2, 4-100% CO2 in N2-CO2). It was shown that the addition of silver based catalysts (Ag, Ag2O, Ag2CO3) into the carbon-carbonate slurry enhanced the performance of the HDCFC....

  8. Carbon Micronymphaea: Graphene on Vertically Aligned Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Jong Won Choi

    2013-01-01

    Full Text Available This paper describes the morphology of carbon nanomaterials such as carbon nanotube (CNT, graphene, and their hybrid structure under various operating conditions during a one-step synthesis via plasma-enhanced chemical vapor deposition (PECVD. We focus on the synthetic aspects of carbon hybrid material composed of heteroepitaxially grown graphene on top of a vertical array of carbon nanotubes, called carbon micronymphaea. We characterize the structural features of this unique nanocomposite by uses of electron microscopy and micro-Raman spectroscopy. We observe carbon nanofibers, poorly aligned and well-aligned vertical arrays of CNT sequentially as the growth temperature increases, while we always discover the carbon hybrids, called carbon micronymphaea, at specific cooling rate of 15°C/s, which is optimal for the carbon precipitation from the Ni nanoparticles in this study. We expect one-pot synthesized graphene-on-nanotube hybrid structure poses great potential for applications that demand ultrahigh surface-to-volume ratios with intact graphitic nature and directional electronic and thermal transports.

  9. Using hybrid method to evaluate carbon footprint of Xiamen City, China

    International Nuclear Information System (INIS)

    Lin, Jianyi; Liu, Yuan; Meng, Fanxin; Cui, Shenghui; Xu, Lilai

    2013-01-01

    For more holistic inventory estimation, this paper uses a hybrid approach to access the carbon footprint of Xiamen City in 2009. Besides carbon emissions from the end-use sector activities (called Scope 1+2 by WRI/WBCSD) in normal research, carbon emissions from the cross-boundary traffic and the embodied energy of key urban imported materials (namely Scope 3) were also included. The results are as follow: (1) Carbon emissions within Scope 1+2 only take up 66.14% of total carbon footprint, while emissions within Scope 3 which have usually been ignored account for 33.84%. (2) Industry is the most carbon-intensive end use sector which contributes 32.74% of the total carbon footprint and 55.13% of energy use emissions in Scope 1+2. (3) The per capita carbon footprint of Xiamen is just about one-third of that in Denver. (4) Comparing with Denver, the proportion of embodied emissions in Xiamen was 10.60% higher than Denver. Overall, Xiamen is relatively a low-carbon city with characters of industrial carbon-intensive and high embodied emissions. Further analysis indicates that the urbanization and industrialization in Xiamen might cause more material consumption and industrial emissions. These highlight the importance of management for Scope 3 emissions in the developing cities. - Highlights: • Carbon emissions from Scope 1+2+3 are calculated for Xiamen City, China. • Carbon footprint in Xiamen is industrial carbon-intensive and high embodied emissions. • Management for Scope 3 emissions in the developing cities is important

  10. Photoconductivity enhancement and charge transport properties in ruthenium-containing block copolymer/carbon nanotube hybrids.

    Science.gov (United States)

    Lo, Kin Cheung; Hau, King In; Chan, Wai Kin

    2018-04-05

    Functional polymer/carbon nanotube (CNT) hybrid materials can serve as a good model for light harvesting systems based on CNTs. This paper presents the synthesis of block copolymer/CNT hybrids and the characterization of their photocurrent responses by both experimental and computational approaches. A series of functional diblock copolymers was synthesized by reversible addition-fragmentation chain transfer polymerizations for the dispersion and functionalization of CNTs. The block copolymers contain photosensitizing ruthenium complexes and modified pyrene-based anchoring units. The photocurrent responses of the polymer/CNT hybrids were measured by photoconductive atomic force microscopy (PCAFM), from which the experimental data were analyzed by vigorous statistical models. The difference in photocurrent response among different hybrids was correlated to the conformations of the hybrids, which were elucidated by molecular dynamics simulations, and the electronic properties of polymers. The photoresponse of the block copolymer/CNT hybrids can be enhanced by introducing an electron-accepting block between the photosensitizing block and the CNT. We have demonstrated that the application of a rigorous statistical methodology can unravel the charge transport properties of these hybrid materials and provide general guidelines for the design of molecular light harvesting systems.

  11. Effect of hybrid system battery performance on determining CO{sub 2} emissions of hybrid electric vehicles in real-world conditions

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, Robert; Schlienger, Peter; Weilenmann, Martin [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Internal Combustion Engines, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland)

    2010-11-15

    Hybrid electric vehicles (HEVs) can potentially reduce vehicle CO{sub 2} emissions by using recuperated kinetic vehicle energy stored as electric energy in a hybrid system battery (HSB). HSB performance affects the individual net HEV CO{sub 2} emissions for a given driving pattern, which is considered to be equivalent to unchanged net energy content in the HSB. The present study investigates the influence of HSB performance on the statutory correction procedure used to determine HEV CO{sub 2} emissions in Europe based on chassis dynamometer measurements with three identical in-use examples of a full HEV model featuring different mileages. Statutory and real-world driving cycles and full electric vehicle operation modes have been considered. The main observation is that the selected HEVs can only use 67-80% of the charge provided to the HSB, which distorts the outcomes of the statutory correction procedure that does not consider such irreversibility. CO{sub 2} emissions corrected according to this procedure underestimate the true net CO{sub 2} emissions of one HEV by approximately 13% in real-world urban driving. The correct CO{sub 2} emissions are only reproduced when considering the HSB performance in this driving pattern. The statutory procedure for correcting HEV CO{sub 2} emissions should, therefore, be adapted. (author)

  12. Hard and transparent hybrid polyurethane coatings using in situ incorporation of calcium carbonate nanoparticles

    International Nuclear Information System (INIS)

    Yao Lu; Yang Jie; Sun Jing; Cai Lifang; He Linghao; Huang Hui; Song Rui; Hao Yongmei

    2011-01-01

    Highlights: → In situ mineralization via gas diffusion was adopted for a good dispersion of calcium carbonate nanoparticles in the polymeric PU matrix. → Hybrid films with high dispersion, transparency, robust and thermal stability can be obtained by controlling the CaCO 3 loading. → The hybrid films display a significant improvement in its water resistance, surface hardness, scratch resistance and flexibility, with the introduction of CaCO 3 , and all coatings exhibited excellent chemical resistance and adhesion. - Abstract: The combination of hardness, scratch resistance, and flexibility is a highly desired feature in many coating applications. The aim of this study is to achieve this goal through the in situ introduction of an unmodified calcium carbonate (CaCO 3 ) into a water-soluble polyurethane (PU) matrix. Smooth and (semi-) transparent films were prepared from both the neat PU and the CaCO 3 -filled composites. As evidenced by the measurements from scanning electron microscopy (SEM), optical microscopy, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA), hybrid films with high dispersion, transparency, robustness and thermal stability could be obtained by controlling the CaCO 3 loading. The storage modulus could increase from 441 MPa of neat PU matrix to 1034 MPa of hybrid film containing 2% (w/w) CaCO 3 . In addition, the same hybrid films displayed a significant improvement in its water resistance. In this case, the water-uptake ratio decreased from 41.54% of PU to 2.21% of hybrid film containing 2% (w/w) CaCO 3 . Moreover, with the introduction of CaCO 3 , conventional coating characterization methods demonstrated an increase in the surface hardness, scratch resistance and flexibility, and all coatings exhibited excellent chemical resistance and adhesion.

  13. Continuous In-situ Measurements of Carbonyl Sulfide to Constrain Ecosystem Carbon and Water Exchange

    Science.gov (United States)

    Rastogi, B.; Kim, Y.; Berkelhammer, M. B.; Noone, D. C.; Lai, C. T.; Hollinger, D. Y.; Bible, K.; Leen, J. B.; Gupta, M.; Still, C. J.

    2014-12-01

    Understanding the processes that control the terrestrial exchange of carbon and water are critical for examining the role of forested ecosystems in changing climates. A small but increasing number of studies have identified Carbonyl Sulfide (OCS) as a potential tracer for photosynthesis. OCS is hydrolyzed by an irreversible reaction in leaf mesophyll cells that is catalyzed by the enzyme, carbonic anhydrase. Leaf-level field and greenhouse studies indicate that OCS uptake is controlled by stomatal activity and that the ratio of OCS and CO2 uptake is reasonably constant. Existing studies on ecosystem OCS exchange have been based on laboratory measurements or short field campaigns and therefore little information on OCS exchange in a natural ecosystem over longer timescales is available. The objective of this study is to further assess the stability of OCS as a tracer for canopy photosynthesis in an active forested ecosystem and also to assess its utility for constraining transpiration, since both fluxes are mediated by canopy stomatal conductance. An off-axis integrated cavity output spectroscopy analyzer (Los Gatos Research Inc.) was deployed at the Wind River Experimental Forest in Washington (45.8205°N, 121.9519°W). Canopy air was sampled from three heights to measure vertical gradients of OCS within the canopy, and OCS exchange between the forest and the atmosphere. Here we take advantage of simultaneous measurements of the stable isotopologues of H2O and CO2 at corresponding heights as well as NEE (Net Ecosystem Exchange) from eddy covariance measurements to compare GPP (Gross Primary Production) and transpiration estimates from a variety of independent techniques. Our findings seek to allow assessment of the environmental and ecophysicological controls on evapotranspiration rates, which are projected to change in coming decades, and are otherwise poorly constrained.

  14. Hybridization of Homopolynucleotides with Different Base Ordering on the Carbon Nanotube Surface

    Czech Academy of Sciences Publication Activity Database

    Karachevtsev, M. V.; Gladchenko, G. O.; Andrushchenko, Valery; Leontiev, V. S.; Karachevtsev, V. A.

    2015-01-01

    Roč. 119, č. 21 (2015), s. 11991-12001 ISSN 1932-7447 R&D Projects: GA ČR GAP208/11/0105; GA ČR GA15-09072S Institutional support: RVO:61388963 Keywords : DNA hybridization * nucleic acids * carbon nanotubes * SWCNT * UV absorption spectroscopy Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.509, year: 2015

  15. Grain Yield Observations Constrain Cropland CO2 Fluxes Over Europe

    Science.gov (United States)

    Combe, M.; de Wit, A. J. W.; Vilà-Guerau de Arellano, J.; van der Molen, M. K.; Magliulo, V.; Peters, W.

    2017-12-01

    Carbon exchange over croplands plays an important role in the European carbon cycle over daily to seasonal time scales. A better description of this exchange in terrestrial biosphere models—most of which currently treat crops as unmanaged grasslands—is needed to improve atmospheric CO2 simulations. In the framework we present here, we model gross European cropland CO2 fluxes with a crop growth model constrained by grain yield observations. Our approach follows a two-step procedure. In the first step, we calculate day-to-day crop carbon fluxes and pools with the WOrld FOod STudies (WOFOST) model. A scaling factor of crop growth is optimized regionally by minimizing the final grain carbon pool difference to crop yield observations from the Statistical Office of the European Union. In a second step, we re-run our WOFOST model for the full European 25 × 25 km gridded domain using the optimized scaling factors. We combine our optimized crop CO2 fluxes with a simple soil respiration model to obtain the net cropland CO2 exchange. We assess our model's ability to represent cropland CO2 exchange using 40 years of observations at seven European FluxNet sites and compare it with carbon fluxes produced by a typical terrestrial biosphere model. We conclude that our new model framework provides a more realistic and strongly observation-driven estimate of carbon exchange over European croplands. Its products will be made available to the scientific community through the ICOS Carbon Portal and serve as a new cropland component in the CarbonTracker Europe inverse model.

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

    Science.gov (United States)

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

    2015-11-13

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

  17. Electrochemical Performance of Low-Carbon Steel in Alkaline Model Solutions Containing Hybrid Aggregates

    NARCIS (Netherlands)

    Koleva, D.A.; Hu, J.; De Wit, J.H.W.; Boshkov, N.; Radeva, T.; Milkova, V.; Van Breugel, K.

    2010-01-01

    This work reports on the electrochemical performance of low-carbon steel electrodes in model alkaline solutions in the presence of 4.9.10-4 g/l hybrid aggregates i.e. cement extract, containing PDADMAC (poly (diallyl, dimethyl ammonium chloride) / PAA (Poly (acrylic acid)/ PDADMAC over a CaO core.

  18. Solar hydrogen hybrid system with carbon storage

    International Nuclear Information System (INIS)

    Zini, G.; Marazzi, R.; Pedrazzi, S.; Tartarini, P.

    2009-01-01

    A complete solar hydrogen hybrid system has been developed to convert, store and use energy from renewable energy sources. The theoretical model has been implemented in a dynamic model-based software environment and applied to real data to simulate its functioning over a one-year period. Results are used to study system design and performance. A photovoltaic sub-system directly drives a residential load and, if a surplus of energy is available, an electrolyzer to produce hydrogen which is stored in a cluster of nitrogen-cooled tanks filled with AX-21 activated carbons. When the power converted from the sun is not sufficient to cover load needs, hydrogen is desorbed from activated carbon tanks and sent to the fuel-cell sub-system so to obtain electrical energy. A set of sub-systems (bus-bar, buck- and boost-converters, inverter, control circuits), handle the electrical power according to a Programmable Logic Control unit so that the load can be driven with adequate Quality of Service. Hydrogen storage is achieved through physisorption (weak van der Waals interactions) between carbon atoms and hydrogen molecules occurring at low temperature (77 K) in carbon porous solids at relatively low pressures. Storage modeling has been developed using a Langmuir-Freundlich 1st type isotherm and experimental data available in literature. Physisorption storage provides safer operations along with good gravimetric (10.8% at 6 MPa) and volumetric (32.5 g/l at 6 MPa) storage capacities at costs that can be comparable to, or smaller than, ordinary storage techniques (compression or liquefaction). Several test runs have been performed on residential user data-sets: the system is capable of providing grid independence and can be designed to yield a surplus production of hydrogen which can be used to recharge electric car batteries or fill tanks for non-stationary uses. (author)

  19. Electrochemical Removal of Radioactive Cesium from Nuclear Waste Using the Dendritic Copper Hexacyanoferrate/Carbon Nanotube Hybrids

    International Nuclear Information System (INIS)

    Zheng, Yuanyuan; Qiao, Junhua; Yuan, Junhua; Shen, Jianfeng; Wang, Ai-jun; Niu, Li

    2017-01-01

    Highlights: •Copper hexacyanoferrate was uniformly covered on carbon nanotubes. •Cs + ion can be exchanged using this hybrid by controlling the electrode potential. •The maximum of Cs + adsorption capacity is 310 mg·g −1 in 50 μM Cs + solution. •The distribution coefficient of Cs + in this hybrid reaches up to 568 L·g −1 ,. •This hybrid can be regenerated with high stability for Cs + exchange. -- Abstract: A novel electrochemical separation system was developed based on copper hexacyanoferrate/multiwalled carbon nanotube (CuHCF/MWCNT) hybrids for selectively removing cesium from wastewater. These CuHCF/MWCNT hybrids were prepared by co-precipitation strategy. The as-prepared CuHCF nanoparticles were uniformly covered on MWCNTs to form a dendritic core-shell structure. This novel structure can improve CuHCFs conductivity, making CuHCFs more accessible for ion exchange. The uptake and release of alkali ion in CuHCF/MWCNT hybrids can be shifted mutually by switching the applied potentials between the anode and cathode. This ion exchange is a fast and reversible process associated with electron transfer in CuHCFs. The potential response depends on the radius of alkali ion. Using this electrochemical adsorption system (EAS), the maximum adsorption capacity (Q max ) of Cs + ion for CuHCFs/MWCNT hybrids reaches up to 310 mg·g −1 in 50 μM Cs + solution with a distribution coefficient K d of 568 L·g −1 , superior to the Cs + removal performance by the conventional adsorption system (Q max 230 mg·g −1 , Kd 389 L·g −1 ). Besides, CuHCF/MWCNT hybrids can be regenerated electrochemically. In addition to the advantages in Cs + removal performance and electrochemical regenerability, they can maintain considerable stability with uptake capacity retention of 85% after 100 cycles of adsorption and regeneration.

  20. Fuel Cell Electrodes Based on Carbon Nanotube/Metallic Nanoparticles Hybrids Formed on Porous Stainless Steel Pellets

    Directory of Open Access Journals (Sweden)

    S. M. Khantimerov

    2013-01-01

    Full Text Available The preparation of carbon nanotube/metallic particle hybrids using pressed porous stainless steel pellets as a substrate is described. The catalytic growth of carbon nanotubes was carried out by CVD on a nickel catalyst obtained by impregnation of pellets with a highly dispersive colloidal solution of nickel acetate tetrahydrate in ethanol. Granular polyethylene was used as the carbon source. Metallic particles were deposited by thermal evaporation of Pt and Ag using pellets with grown carbon nanotubes as a base. The use of such composites as fuel cell electrodes is discussed.

  1. Government control or low carbon lifestyle? – Analysis and application of a novel selective-constrained energy-saving and emission-reduction dynamic evolution system

    International Nuclear Information System (INIS)

    Fang, Guochang; Tian, Lixin; Fu, Min; Sun, Mei

    2014-01-01

    This paper explores a novel selective-constrained energy-saving and emission-reduction (ESER) dynamic evolution system, analyzing the impact of cost of conserved energy (CCE), government control, low carbon lifestyle and investment in new technology of ESER on energy intensity and economic growth. Based on artificial neural network, the quantitative coefficients of the actual system are identified. Taking the real situation in China for instance, an empirical study is undertaken by adjusting the parameters of the actual system. The dynamic evolution behavior of energy intensity and economic growth in reality are observed, with the results in perfect agreement with actual situation. The research shows that the introduction of CCE into ESER system will have certain restrictive effect on energy intensity in the earlier period. However, with the further development of the actual system, carbon emissions could be better controlled and energy intensity would decline. In the long run, the impacts of CCE on economic growth are positive. Government control and low carbon lifestyle play a decisive role in controlling ESER system and declining energy intensity. But the influence of government control on economic growth should be considered at the same time and the controlling effect of low carbon lifestyle on energy intensity should be strengthened gradually, while the investment in new technology of ESER can be neglected. Two different cases of ESER are proposed after a comprehensive analysis. The relations between variables and constraint conditions in the ESER system are harmonized remarkably. A better solution to carry out ESER is put forward at last, with numerical simulations being carried out to demonstrate the results. - Highlights: • Use of nonlinear dynamical method to model the selective-constrained ESER system. • Monotonic evolution curves of energy intensity and economic growth are obtained. • Detailed analysis of the game between government control and low

  2. Study of emissions and fuel economy for parallel hybrid versus conventional vehicles on real world and standard driving cycles

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Samari

    2017-12-01

    Full Text Available Parallel hybrid electric vehicles (PHEVs increasing rapidly in the automobile markets. However, the benefits out of using this kind of vehicles are still concerned a lot of costumers. This work investigated the expected benefits (such as decreasing emissions and increasing fuel economy from using the parallel HEV in comparison to the conventional vehicle model of the real-world and standard driving cycles. The software Autonomie used in this study to simulate the parallel HEV and conventional models on these driving cycles.The results show that the fuel economy (FE can be improved significantly up to 68% on real-world driving cycle, which is represented mostly city activities. However, the FE improvement was limited (10% on the highway driving cycle, and this is expected since the using of brake system was infrequent. Moreover, the emissions from parallel HEV decreased about 40% on the real-world driving cycle, and decreased 11% on the highway driving cycle. Finally, the engine efficiency, improved about 12% on the real-world driving cycle, and about 7% on highway driving cycle. Keywords: Emissions, Hybrid electric vehicles, Fuel economy, Real-world driving cycle

  3. Analysis of composition and microstructural uniformity of hybrid glass/carbon fibre composites

    Energy Technology Data Exchange (ETDEWEB)

    Beauson, J.; Markussen, C.M.; Madsen, Bo

    2013-09-01

    In hybrid fibre composites, the intermixing of the two types of fibres imposes challenges to obtain materials with a well-defined and uniform microstructure. In the present paper, the composition and the microstructural uniformity of hybrid glass/carbon fibre composites mixed at the fibre bundle level are investigated. The different levels of compositions in the composites are defined and experimentally determined. The composite volume fractions are determined using an image analysis based procedure. The global fibre volume fractions are determined using a gravimetrical based method. The local fibre volume fractions are determined using volumetric calculations. A model is presented to predict the interrelation of volume fractions in hybrid fibre composites. The microstructural uniformity of the composites is analysed by the determined variation in composite volume fractions. Two analytical methods, a standard deviation based method and a fast Fourier transform method, are used to quantify the difference in microstructural uniformity between composites, and to detect and quantify any repeating pattern in the composite microstructure. (Author)

  4. Modeling plasma-assisted growth of graphene-carbon nanotube hybrid

    International Nuclear Information System (INIS)

    Tewari, Aarti

    2016-01-01

    A theoretical model describing the growth of graphene-CNT hybrid in a plasma medium is presented. Using the model, the growth of carbon nanotube (CNT) on a catalyst particle and thereafter the growth of the graphene on the CNT is studied under the purview of plasma sheath and number density kinetics of different plasma species. It is found that the plasma parameter such as ion density; gas ratios and process parameter such as source power affect the CNT and graphene dimensions. The variation in growth rates of graphene and CNT under different plasma power, gas ratios, and ion densities is analyzed. Based on the results obtained, it can be concluded that higher hydrocarbon ion densities and gas ratios of hydrocarbon to hydrogen favor the growth of taller CNTs and graphene, respectively. In addition, the CNT tip radius reduces with hydrogen ion density and higher plasma power favors graphene with lesser thickness. The present study can help in better understanding of the graphene-CNT hybrid growth in a plasma medium.

  5. Modeling plasma-assisted growth of graphene-carbon nanotube hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Tewari, Aarti [Department of Applied Physics, Delhi Technological University, Shahbad Daulatpur, Bawana Road, Delhi 110 042 (India)

    2016-08-15

    A theoretical model describing the growth of graphene-CNT hybrid in a plasma medium is presented. Using the model, the growth of carbon nanotube (CNT) on a catalyst particle and thereafter the growth of the graphene on the CNT is studied under the purview of plasma sheath and number density kinetics of different plasma species. It is found that the plasma parameter such as ion density; gas ratios and process parameter such as source power affect the CNT and graphene dimensions. The variation in growth rates of graphene and CNT under different plasma power, gas ratios, and ion densities is analyzed. Based on the results obtained, it can be concluded that higher hydrocarbon ion densities and gas ratios of hydrocarbon to hydrogen favor the growth of taller CNTs and graphene, respectively. In addition, the CNT tip radius reduces with hydrogen ion density and higher plasma power favors graphene with lesser thickness. The present study can help in better understanding of the graphene-CNT hybrid growth in a plasma medium.

  6. Interaction of both plasmas in CO2 laser-MAG hybrid welding of carbon steel

    Science.gov (United States)

    Kutsuna, Muneharu; Chen, Liang

    2003-03-01

    Researches and developments of laser and arc hybrid welding has been curried out since in 1978. Especially, CO2 laser and TIG hybrid welding has been studied for increasing the penetration depth and welding speed. Recently laser and MIG/MAG/Plasma hybrid welding processes have been developed and applied to industries. It was recognized as a new welding process that promote the flexibility of the process for increasing the penetration depth, welding speed and allowable joint gap and improving the quality of the welds. In the present work, CO2 Laser-MAG hybrid welding of carbon steel (SM490) was investigated to make clear the phenomenon and characteristics of hybrid welding process comparing with laser welding and MAG process. The effects of many process parameters such as welding current, arc voltage, welding speed, defocusing distance, laser-to-arc distance on penetration depth, bead shape, spatter, arc stability and plasma formation were investigated in the present work. Especially, the interaction of laser plasma and MAG arc plasma was considered by changing the laser to arc distance (=DLA).

  7. Polyvinyl alcohol (PVA)-cellulose nanofibril (CNF)-multiwalled carbon nanotube (MWCNT) hybrid organic aerogels with superior mechanical properties

    Science.gov (United States)

    Qifeng Zheng; Alireza Javadi; Ronald Sabo; Zhiyong Cai; Shaoqin Gong

    2013-01-01

    Polyvinyl alcohol (PVA)–cellulose nanofibril (CNF)–multiwalled carbon nanotube (MWCNT) hybrid organic aerogels were prepared using an environmentally friendly freeze-drying process with renewable materials. The material properties of these “green” hybrid aerogels were characterized extensively using various techniques. It was found that adding a small amount of CNFs...

  8. The Effect of Clay/Multiwall Carbon Nanotube Hybrid Fillers on the Properties of Elastomer Nanocomposites

    Directory of Open Access Journals (Sweden)

    Sung Ho Song

    2018-01-01

    Full Text Available The hybrid fillers of 1D multiwalled carbon nanotubes (MWNT and 2D montmorillonite (MMT have led to excellent physical and chemical properties in high performance elastomer nanocomposites. In this study, the hybridization of PDDA (polydiallyldimethylammonium chloride functionalized MWNT (P-MWNT and hydroxyl-functionalized MMT (H-MMT was prepared by the electrostatic interaction between the positive charge on the MWNT and the negative charge on the MMT using a simple solution mixing process. Also, a styrene-butadiene rubber (SBR nanocomposite containing the hybrid nanofillers was prepared to improve the dispersion of nanofillers with SBR latex. The SBR nanocomposites with the hybrid nanofillers exhibited outstanding mechanical properties including modulus, tensile strength, and elongation at break, due to the enhanced interfacial bonding with the elastomer matrix. Furthermore, the hybrid nanofillers in the SBR matrix showed superior thermal and electrical properties and gas barrier performance at low loadings. The synergistic effects of the SBR produced by the hybridized nanofillers will open up new opportunities for elastomer composites with high performance.

  9. Improved functionality of graphene and carbon nanotube hybrid foam architecture by UV-ozone treatment

    Science.gov (United States)

    Wang, Wei; Ruiz, Isaac; Lee, Ilkeun; Zaera, Francisco; Ozkan, Mihrimah; Ozkan, Cengiz S.

    2015-04-01

    Optimization of the electrode/electrolyte double-layer interface is a key factor for improving electrode performance of aqueous electrolyte based supercapacitors (SCs). Here, we report the improved functionality of carbon materials via a non-invasive, high-throughput, and inexpensive UV generated ozone (UV-ozone) treatment. This process allows precise tuning of the graphene and carbon nanotube hybrid foam (GM) transitionally from ultrahydrophobic to hydrophilic within 60 s. The continuous tuning of surface energy can be controlled by simply varying the UV-ozone exposure time, while the ozone-oxidized carbon nanostructure maintains its integrity. Symmetric SCs based on the UV-ozone treated GM foam demonstrated enhanced rate performance. This technique can be readily applied to other CVD-grown carbonaceous materials by taking advantage of its ease of processing, low cost, scalability, and controllability.Optimization of the electrode/electrolyte double-layer interface is a key factor for improving electrode performance of aqueous electrolyte based supercapacitors (SCs). Here, we report the improved functionality of carbon materials via a non-invasive, high-throughput, and inexpensive UV generated ozone (UV-ozone) treatment. This process allows precise tuning of the graphene and carbon nanotube hybrid foam (GM) transitionally from ultrahydrophobic to hydrophilic within 60 s. The continuous tuning of surface energy can be controlled by simply varying the UV-ozone exposure time, while the ozone-oxidized carbon nanostructure maintains its integrity. Symmetric SCs based on the UV-ozone treated GM foam demonstrated enhanced rate performance. This technique can be readily applied to other CVD-grown carbonaceous materials by taking advantage of its ease of processing, low cost, scalability, and controllability. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06795a

  10. Feasibility Analyses of Developing Low Carbon City with Hybrid Energy Systems in China: The Case of Shenzhen

    Directory of Open Access Journals (Sweden)

    Xun Zhang

    2016-05-01

    Full Text Available As the largest carbon emission source in China, the power sector grows rapidly owing to the country’s unprecedented urbanization and industrialization processes. In order to explore a low carbon urbanization pathway by reducing carbon emissions of the power sector, the Chinese government launched an international low carbon city (ILCC project in Shenzhen. This paper presents a feasibility analysis on the potential hybrid energy system based on local renewable energy resources and electricity demand estimation over the three planning stages of the ILCC project. Wind power, solar power, natural gas and the existing power grid are components considered in the hybrid energy system. The simulation results indicate that the costs of energy in the three planning stages are 0.122, 0.105 and 0.141 $/kWh, respectively, if external wind farms and pumped storage hydro stations (PSHSs exist. The optimization results reveal that the carbon reduction rates are 46.81%, 62.99% and 75.76% compared with the Business as Usual scenarios. The widely distributed water reservoirs in Shenzhen provide ideal conditions to construct PSHS, which is crucial in enhancing renewable energy utilization.

  11. Facile synthesis of graphene oxide @ mesoporous carbon hybrid nanocomposites for lithium sulfur battery

    International Nuclear Information System (INIS)

    Bao, Weizhai; Zhang, Zhian; Chen, Wei; Zhou, Chengkun; Lai, Yanqing; Li, Jie

    2014-01-01

    Graphical abstract: - Highlights: • A novel design and synthesis of GO@Meso-C using GO@MOF-5 as precursor. • GO@Meso-C hybrid material as a host material was applied for sulfur cathode. • Electrochemical performances were improved in sulfur cathode using Go@Meso-C. - Abstract: We present a design and synthesis of a hierarchical architecture of graphene oxide @ mesoporous carbon (GO@Meso-C) using graphene oxide @ metal-organic framework hybrid materials (GO@MOF-5) as both the template and precursor. Active sulfur is encapsulated into the GO@Meso-C matrix prepared via carbonize GO@MOF-5 polyhedrons for high performance lithium sulfur battery. The initial and 100th cycle discharge capacity of GO@Meso-C/S sulfur cathode are as high as 1122 mAh g −1 and 820 mAh g −1 at a current rate of 0.2 C. The remarkably high special capacity and capacity retention rate indicate that the GO@Meso-C is a promising host material for the sulfur cathode in the lithium sulfur battery applications

  12. Controllable preparation of multi-dimensional hybrid materials of nickel-cobalt layered double hydroxide nanorods/nanosheets on electrospun carbon nanofibers for high-performance supercapacitors

    International Nuclear Information System (INIS)

    Lai, Feili; Huang, Yunpeng; Miao, Yue-E; Liu, Tianxi

    2015-01-01

    Graphical Abstract: Multi-dimensional hybrid materials of nickel-cobalt layered double hydroxide nanorods/nanosheets grown on electrospun carbon nanofiber membranes were prepared via electrospinning combined with solution co-deposition for high-performance supercapacitor electrodes. - Highlights: • Ni-Co LDH@CNFhybridswerepreparedbyelectrospinningandsolutionco-deposition. • Ni-Co LDH@CNF hybrids show high electrochemical performance for supercapacitors. • This method can be extended to other bimetallic@CNF hybrids for electrode materials. - Abstract: Hybrid nanomaterials with hierarchical structures have been considered as one kind of the most promising electrode materials for high-performance supercapacitors with high capacity and long cycle lifetime. In this work, multi-dimensional hybrid materials of nickel-cobalt layered double hydroxide (Ni-Co LDH) nanorods/nanosheets on carbon nanofibers (CNFs) were prepared by electrospinning technique combined with one-step solution co-deposition method. Carbon nanofiber membranes were obtained by electrospinning of polyacrylonitrile (PAN) followed by pre-oxidation and carbonization. The successful growth of Ni-Co LDH with different morphologies on CNF membrane by using two kinds of auxiliary agents reveals the simplicity and universality of this method. The uniform and immense growth of Ni-Co LDH on CNFs significantly improves its dispersion and distribution. Meanwhile the hierarchical structure of carbon nanofiber@nickel-cobalt layered double hydroxide nanorods/nanosheets (CNF@Ni-Co LDH NR/NS) hybrid membranes provide not only more active sites for electrochemical reaction but also more efficient pathways for electron transport. Galvanostatic charge-discharge measurements reveal high specific capacitances of 1378.2 F g −1 and 1195.4 F g −1 (based on Ni-Co LDH mass) at 1 A g −1 for CNF@Ni-Co LDH NR and CNF@Ni-Co LDH NS hybrid membranes, respectively. Moreover, cycling stabilities for both hybrid membranes are

  13. A data assimilation framework for constraining upscaled cropland carbon flux seasonality and biometry with MODIS

    Directory of Open Access Journals (Sweden)

    O. Sus

    2013-04-01

    , observing carbon cycling at one single field with its individual sowing pattern is not sufficient to constrain large-scale agroecosystem carbon flux seasonality. Study area average growing season length is 20 days longer than observed at Bondville, primarily because of an earlier estimated start of season. (3 For carbon budgeting, additional information on cropland soil management and belowground carbon cycling has to be considered, as such constraints are not provided by MODIS.

  14. Improvement of Fracture Toughness in Epoxy Nanocomposites through Chemical Hybridization of Carbon Nanotubes and Alumina.

    Science.gov (United States)

    Zakaria, Muhammad Razlan; Abdul Kudus, Muhammad Helmi; Md Akil, Hazizan; Zamri, Mohd Hafiz

    2017-03-16

    The current study investigated the effect of adding a carbon nanotube-alumina (CNT-Al₂O₃) hybrid on the fracture toughness of epoxy nanocomposites. The CNT-Al₂O₃ hybrid was synthesised by growing CNTs on Al₂O₃ particles via the chemical vapour deposition method. The CNTs were strongly attached onto the Al₂O₃ particles, which served to transport and disperse the CNTs homogenously, and to prevent agglomeration in the CNTs. The experimental results demonstrated that the CNT-Al₂O₃ hybrid-filled epoxy nanocomposites showed improvement in terms of the fracture toughness, as indicated by an increase of up to 26% in the critical stress intensity factor, K 1 C , compared to neat epoxy.

  15. Real-world environmental performance of hybrid vehicles

    NARCIS (Netherlands)

    Winkel, R.G.; Hendriksen, P.; Vermeulen, R.J.; Foster, D.L.

    2001-01-01

    With the further development and market introduction of hybrid vehicle technologies in recent years we are now at a stage where we can test whether the proclaimed advantages of hybrid propulsion in terms of fuel efficiency and emission reduction are actually realised. An important issue is that

  16. The concept of a novel hybrid smart composite reinforced with radially aligned zigzag carbon nanotubes on piezoelectric fibers

    International Nuclear Information System (INIS)

    Ray, M C

    2010-01-01

    A new hybrid piezoelectric composite (HPZC) reinforced with zigzag single-walled carbon nanotubes (CNTs) and piezoelectric fibers is proposed. The novel constructional feature of this composite is that the uniformly aligned CNTs are radially grown on the surface of piezoelectric fibers. A micromechanics model is derived to estimate the effective piezoelectric and elastic properties. It is found that the effective piezoelectric coefficient e 31 of the proposed HPZC, which accounts for the in-plane actuation, is significantly higher than that of the existing 1-3 piezoelectric composite without reinforcement with carbon nanotubes and the previously reported hybrid piezoelectric composite (Ray and Batra 2009 ASME J. Appl. Mech. 76 034503)

  17. Electrocatalytic behaviour of hybrid cobalt–manganese hexacyanoferrate film on glassy carbon electrode

    International Nuclear Information System (INIS)

    Vinu Mohan, A.M.; Rambabu, Gutru; Aswini, K.K.; Biju, V.M.

    2014-01-01

    A thin film of hybrid cobalt–manganese hexacyanoferrate (CoMnHCF), a redox mediator was electrodeposited on a glassy carbon (GC) electrode and was employed as an amperometric sensor towards L-Tryptophan (L-Trp). The hybrid film was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction technique (XRD), scanning electron microscope–energy dispersive X-ray spectroscopy (SEM–EDAX), and electrochemical techniques. The atomic absorption spectroscopic analysis provided the stoichiometry of the hybrid film to be K 1.74-y Co y Mn 0.78 [Fe(CN) 6 ], y ≤ 0.68. The electrochemical impedance study revealed the excellent charge transfer properties of GC/CoMnHCF electrode. The voltammetric investigations demonstrated exceptional electrocatalytic properties of the hybrid film modified electrode when compared to that of bare GC, GC/CoHCF and GC/MnHCF electrodes, towards the L-Trp oxidation. The kinetic parameters such as electron transfer coefficient, the electron transfer rate constant, the diffusion coefficient and the catalytic rate constant for the electrooxidation process of L-Trp were investigated. The amperometric detection of L-Trp employing GC/CoMnHCF electrode possessed a good sensitivity of 10 × 10 −2 A M −1 cm −2 in a wide range of detection (2–200 μM) at a reduced overpotential of 680 mV. In addition, the proposed amperometric method was applied to the detection of L-Trp in commercial milk samples with reproducible results. - Highlights: • A hybrid cobalt–manganese hexacyanoferrate film was prepared. • The hybrid film possesses excellent charge transfer properties. • The hybrid film exhibits excellent electrocatalytic properties towards Tryptophan. • Tryptophan detection is possible from commercial milk samples

  18. Facile fabrication of boron nitride nanosheets-amorphous carbon hybrid film for optoelectronic applications

    KAUST Repository

    Wan, Shanhong

    2015-01-01

    A novel boron nitride nanosheets (BNNSs)-amorphous carbon (a-C) hybrid film has been deposited successfully on silicon substrates by simultaneous electrochemical deposition, and showed a good integrity of this B-C-N composite film by the interfacial bonding. This synthesis can potentially provide the facile control of the B-C-N composite film for the potential optoelectronic devices. This journal is

  19. A Novel Activated-Charcoal-Doped Multiwalled Carbon Nanotube Hybrid for Quasi-Solid-State Dye-Sensitized Solar Cell Outperforming Pt Electrode.

    Science.gov (United States)

    Arbab, Alvira Ayoub; Sun, Kyung Chul; Sahito, Iftikhar Ali; Qadir, Muhammad Bilal; Choi, Yun Seon; Jeong, Sung Hoon

    2016-03-23

    Highly conductive mesoporous carbon structures based on multiwalled carbon nanotubes (MWCNTs) and activated charcoal (AC) were synthesized by an enzymatic dispersion method. The synthesized carbon configuration consists of synchronized structures of highly conductive MWCNT and porous activated charcoal morphology. The proposed carbon structure was used as counter electrode (CE) for quasi-solid-state dye-sensitized solar cells (DSSCs). The AC-doped MWCNT hybrid showed much enhanced electrocatalytic activity (ECA) toward polymer gel electrolyte and revealed a charge transfer resistance (RCT) of 0.60 Ω, demonstrating a fast electron transport mechanism. The exceptional electrocatalytic activity and high conductivity of the AC-doped MWCNT hybrid CE are associated with its synchronized features of high surface area and electronic conductivity, which produces higher interfacial reaction with the quasi-solid electrolyte. Morphological studies confirm the forms of amorphous and conductive 3D carbon structure with high density of CNT colloid. The excessive oxygen surface groups and defect-rich structure can entrap an excessive volume of quasi-solid electrolyte and locate multiple sites for iodide/triiodide catalytic reaction. The resultant D719 DSSC composed of this novel hybrid CE fabricated with polymer gel electrolyte demonstrated an efficiency of 10.05% with a high fill factor (83%), outperforming the Pt electrode. Such facile synthesis of CE together with low cost and sustainability supports the proposed DSSCs' structure to stand out as an efficient next-generation photovoltaic device.

  20. Studies of world carbon fiber industry from a perspective of patent analysis

    Institute of Scientific and Technical Information of China (English)

    郑佳

    2016-01-01

    Patents are the manifestation of the industry R&D endeavor;therefore, World carbon fiber in-dustry from the perspective of patent analysis is studied .Findings from the analysis show a continual increase of carbon fibers patents since 1969 , and the growth rate began even faster after the year of 2005.Five countries (Japan, China, US, Germany and Korea) took dominant positions in global carbon fibers R&D , and the sum of patents applied in these five countries accounted for 80%of the total patents in the world .Corporations do play an active role in global carbon fibers R&D , and over 60%of patents were applied by corporations .Among them , the top 3 corporations were all from Ja-pan, which had much more patents than the other patent assignees .Furthermore, most corporations were not active in cooperation with others , except Toyota Motor Corp .Global carbon fibers R&D fo-cused on sheet manufacture cloth , core wire layer , heat connect provide and filter activated draw . And there is big difference between Japan and China in the R&D focus .China ’ s corporations have exhibited rapid growth in the number of patent applications in recent years , but there is still a large gap between China and foreign countries in view of global patent layout and influence .By providing the insight into the evolution of global carbon fibers industrial and technological development through the perspective of patent analysis , this study hopes to provide an objective statistic reference for fu-ture policy directions and academic researches .

  1. Encapsulated Vanadium-Based Hybrids in Amorphous N-Doped Carbon Matrix as Anode Materials for Lithium-Ion Batteries.

    Science.gov (United States)

    Long, Bei; Balogun, Muhammad-Sadeeq; Luo, Lei; Luo, Yang; Qiu, Weitao; Song, Shuqin; Zhang, Lei; Tong, Yexiang

    2017-11-01

    Recently, researchers have made significant advancement in employing transition metal compound hybrids as anode material for lithium-ion batteries and developing simple preparation of these hybrids. To this end, this study reports a facile and scalable method for fabricating a vanadium oxide-nitride composite encapsulated in amorphous carbon matrix by simply mixing ammonium metavanadate and melamine as anode materials for lithium-ion batteries. By tuning the annealing temperature of the mixture, different hybrids of vanadium oxide-nitride compounds are synthesized. The electrode material prepared at 700 °C, i.e., VM-700, exhibits excellent cyclic stability retaining 92% of its reversible capacity after 200 cycles at a current density of 0.5 A g -1 and attractive rate performance (220 mAh g -1 ) under the current density of up to 2 A g -1 . The outstanding electrochemical properties can be attributed to the synergistic effect from heterojunction form by the vanadium compound hybrids, the improved ability of the excellent conductive carbon for electron transfer, and restraining the expansion and aggregation of vanadium oxide-nitride in cycling. These interesting findings will provide a reference for the preparation of transition metal oxide and nitride composites as well. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Hybrid Carbon-Based Scaffolds for Applications in Soft Tissue Reconstruction

    Science.gov (United States)

    Lafdi, Khalid; Joseph, Robert M.; Tsonis, Panagiotis A.

    2012-01-01

    Current biomedical scaffolds utilized in surgery to repair soft tissues commonly fail to meet the optimal combination of biomechanical and tissue regenerative properties. Carbon is a scaffold alternative that potentially optimizes the balance between mechanical strength, durability, and function as a cell and biologics delivery vehicle that is necessary to restore tissue function while promoting tissue repair. The goals of this study were to investigate the feasibility of fabricating hybrid fibrous carbon scaffolds modified with biopolymer, polycaprolactone and to analyze their mechanical properties and ability to support cell growth and proliferation. Environmental scanning electron microscopy, micro-computed tomography, and cell adhesion and cell proliferation studies were utilized to test scaffold suitability as a cell delivery vehicle. Mechanical properties were tested to examine load failure and elastic modulus. Results were compared to an acellular dermal matrix scaffold control (GraftJacket® [GJ] Matrix), selected for its common use in surgery for the repair of soft tissues. Results indicated that carbon scaffolds exhibited similar mechanical maximums and capacity to support fibroblast adhesion and proliferation in comparison with GJ. Fibroblast adhesion and proliferation was collinear with carbon fiber orientation in regions of sparsely distributed fibers and occurred in clusters in regions of higher fiber density and low porosity. Overall, fibroblast adhesion and proliferation was greatest in lower porosity carbon scaffolds with highly aligned fibers. Stepwise multivariate regression showed that the variability in maximum load of carbon scaffolds and controls were dependent on unique and separate sets of parameters. These finding suggested that there were significant differences in the functional implications of scaffold design and material properties between carbon and dermis derived scaffolds that affect scaffold utility as a tissue replacement

  3. Mediated Electron Transfer at Vertically Aligned Single-Walled Carbon Nanotube Electrodes During Detection of DNA Hybridization

    Science.gov (United States)

    Wallen, Rachel; Gokarn, Nirmal; Bercea, Priscila; Grzincic, Elissa; Bandyopadhyay, Krisanu

    2015-06-01

    Vertically aligned single-walled carbon nanotube (VASWCNT) assemblies are generated on cysteamine and 2-mercaptoethanol (2-ME)-functionalized gold surfaces through amide bond formation between carboxylic groups generated at the end of acid-shortened single-walled carbon nanotubes (SWCNTs) and amine groups present on the gold surfaces. Atomic force microscopy (AFM) imaging confirms the vertical alignment mode of SWCNT attachment through significant changes in surface roughness compared to bare gold surfaces and the lack of any horizontally aligned SWCNTs present. These SWCNT assemblies are further modified with an amine-terminated single-stranded probe-DNA. Subsequent hybridization of the surface-bound probe-DNA in the presence of complementary strands in solution is followed using impedance measurements in the presence of Fe(CN)6 3-/4- as the redox probe in solution, which show changes in the interfacial electrochemical properties, specifically the charge-transfer resistance, due to hybridization. In addition, hybridization of the probe-DNA is also compared when it is attached directly to the gold surfaces without any intermediary SWCNTs. Contrary to our expectations, impedance measurements show a decrease in charge-transfer resistance with time due to hybridization with 300 nM complementary DNA in solution with the probe-DNA attached to SWCNTs. In contrast, an increase in charge-transfer resistance is observed with time during hybridization when the probe-DNA is attached directly to the gold surfaces. The decrease in charge-transfer resistance during hybridization in the presence of VASWCNTs indicates an enhancement in the electron transfer process of the redox probe at the VASWCNT-modified electrode. The results suggest that VASWCNTs are acting as mediators of electron transfer, which facilitate the charge transfer of the redox probe at the electrode-solution interface.

  4. IrOx-carbon nanotube hybrids: a nanostructured material for electrodes with increased charge capacity in neural systems.

    Science.gov (United States)

    Carretero, Nina M; Lichtenstein, Mathieu P; Pérez, Estela; Cabana, Laura; Suñol, Cristina; Casañ-Pastor, Nieves

    2014-10-01

    Nanostructured iridium oxide-carbon nanotube hybrids (IrOx-CNT) deposited as thin films by dynamic electrochemical methods are suggested as novel materials for neural electrodes. Single-walled carbon nanotubes (SWCNT) serve as scaffolds for growing the oxide, yielding a tridimensional structure with improved physical, chemical and electrical properties, in addition to high biocompatibility. In biological environments, SWCNT encapsulation by IrOx makes more resistant electrodes and prevents the nanotube release to the media, preventing cellular toxicity. Chemical, electrochemical, structural and surface characterization of the hybrids has been accomplished. The high performance of the material in electrochemical measurements and the significant increase in cathodal charge storage capacity obtained for the hybrid in comparison with bare IrOx represent a significant advance in electric field application in biosystems, while its cyclability is also an order of magnitude greater than pure IrOx. Moreover, experiments using in vitro neuronal cultures suggest high biocompatibility for IrOx-CNT coatings and full functionality of neurons, validating this material for use in neural electrodes. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  5. One-pot synthesis of polyamines improved magnetism and fluorescence Fe3O4-carbon dots hybrid NPs for dual modal imaging.

    Science.gov (United States)

    Li, Bo; Wang, Xudong; Guo, Yali; Iqbal, Anam; Dong, Yaping; Li, Wu; Liu, Weisheng; Qin, Wenwu; Chen, Shizhen; Zhou, Xin; Yang, Yunhuang

    2016-04-07

    A one-step hydrothermal method was developed to fabricate Fe3O4-carbon dots (Fe3O4-CDs) magnetic-fluorescent hybrid nanoparticles (NPs). Ferric ammonium citrate (FAC) was used as a cheap and nontoxic iron precursor and as the carbon source. Moreover, triethylenetetramine (TETA) was used to improve the adhesive strength of CDs on Fe3O4 and the fluorescence intensity of CDs. The prepared water-soluble hybrid NPs not only exhibit excellent superparamagnetic properties (Ms = 56.8 emu g(-1)), but also demonstrate excitation-independent photoluminescence for down-conversion and up-conversion at 445 nm. Moreover, the prepared water-soluble Fe3O4-CDs hybrid NPs have a dual modal imaging ability for both magnetic resonance imaging (MRI) and fluorescence imaging.

  6. Amperometric glucose biosensor based on glucose oxidase dispersed in multiwalled carbon nanotubes/graphene oxide hybrid biocomposite.

    Science.gov (United States)

    Palanisamy, Selvakumar; Cheemalapati, Srikanth; Chen, Shen-Ming

    2014-01-01

    An amperometric glucose biosensor based on enhanced and fast direct electron transfer (DET) of glucose oxidase (GOx) at enzyme dispersed multiwalled carbon nanotubes/graphene oxide (MWCNT/GO) hybrid biocomposite was developed. The fabricated hybrid biocomposite was characterized by transmission electron microscopy (TEM), Raman and infrared spectroscopy (IR). The TEM image of hybrid biocomposite reveals that a thin layer of GOx was covered on the surface of MWCNT/GO hybrid composite. IR results validate that the hybrid biocomposite was formed through the electrostatic interactions between GOx and MWCNT/GO hybrid composite. Further, MWCNT/GO hybrid composite has also been characterized by TEM and UV-visible spectroscopy. A pair of well-defined redox peak was observed for GOx immobilized at the hybrid biocomposite electrode than that immobilized at the MWCNT modified electrode. The electron transfer rate constant (Ks) of GOx at the hybrid biocomposite was calculated to be 11.22s(-1). The higher Ks value revealed that fast DET of GOx occurred at the electrode surface. Moreover, fabricated biosensor showed a good sensitivity towards glucose oxidation over a linear range 0.05-23.2mM. The limit of detection (LOD) was estimated to be 28μM. The good features of the proposed biosensor could be used for the accurate detection of glucose in the biological samples. © 2013.

  7. Enhancement of sp3 hybridized C in amorphous carbon films by Ar ion bombardment and Si incorporation

    International Nuclear Information System (INIS)

    Jung, Hae-Suk; Park, Hyung-Ho; Mendieta, I.R.; Smith, D.A.

    2003-01-01

    We report an effective method of increasing the sp 3 hybridization fraction in sputtered amorphous carbon (a-C) film by the combination of Ar ion bombardment and Si incorporation. In the deposition of an a-C film, Ar ion bombardment by controlling the applied bias voltage plays a role in creating high stress in film and causes the local bonding configuration to change to a sp 3 hybridized bond. Simultaneously, the incorporated Si in an a-C network breaks the sp 2 hybridized bonded ring and promotes the formation of a sp 3 hybridized bond. This enhancement of the sp 3 hybridized bonding characteristic is maximized for an a-C film with 23 at. % of Si and 100-150 V of applied bias voltage. In this region, the increase of resistivity, optical band gap, and mechanical hardness of a-C is attributed to the reduction of the sp 2 hybridized bonded ring and increased fraction of the sp 3 hybridized bond. However, at a higher bias voltage above 150 V, the enhancement effect is reduced due to the resputtering and thermally activated reconversion of a sp 3 to a sp 2 hybridized bond

  8. A competitive carbon emissions scheme with hybrid fiscal incentives: The evidence from a taxi industry

    International Nuclear Information System (INIS)

    Liu, Yang; Han, Liyan; Yin, Ziqiao; Luo, Kongyi

    2017-01-01

    As two major approaches to reduce carbon emissions, command-and-control instruments and market-based carbon trading systems have their own weaknesses. Our paper first proposes a type of endogenous equilibrium methodology to dynamically derive the industrial carbon emissions standards. At the equilibrium, the sum of all carbon assets and liabilities is zero in the considered industry. Moreover, the standards fall over time with low-carbon technological advance. Most importantly, combining Pigou's and Coase's ideas, we construct a fiscal instrument accounting for both carbon taxes and allowances based on the dynamically improved emissions standards and carbon trading prices. This “No revenue for government” method implements a self-operated ecology for carbon trading market. Finally, considering the “Waterloo” recession of carbon prices, we introduce an adjustment factor into the model, which generates a negative-feedback mechanism with carbon prices. To support our idea, we present the application to Beijing taxi industry in detail and raise relative policy implications based on the evidence. - Highlights: • Dynamic endogenous equilibrium standards for carbon emissions. • A public policy oriented market mechanism combining command-and-control instruments and carbon trading. • Hybrid incentives to emission reduction combining carbon taxes and allowances. • The adjustment coefficient generating a negative feedback mechanism with carbon prices.

  9. Could a secular increase in organic burial explain the rise of oxygen? Insights from a geological carbon cycle model constrained by the carbon isotope record

    Science.gov (United States)

    Krissansen-Totton, J.; Kipp, M.; Catling, D. C.

    2017-12-01

    The stable isotopes of carbon in marine sedimentary rock provide a window into the evolution of the Earth system. Conventionally, a relatively constant carbon isotope ratio in marine sedimentary rocks has been interpreted as implying constant organic carbon burial relative to total carbon burial. Because organic carbon burial corresponds to net oxygen production from photosynthesis, it follows that secular changes in the oxygen source flux cannot explain the dramatic rise of oxygen over Earth history. Instead, secular declines in oxygen sink fluxes are often invoked as causes for the rise of oxygen. However, constant fractional organic burial is difficult to reconcile with tentative evidence for low phosphate concentrations in the Archean ocean, which would imply lower marine productivity and—all else being equal—less organic carbon burial than today. The conventional interpretation of the carbon isotope record rests on the untested assumption that the isotopic ratio of carbon inputs into the ocean reflect mantle isotopic values throughout Earth history. In practice, differing rates of carbonate and organic weathering will allow for changes in isotopic inputs, as suggested by [1] and [2]. However, these inputs can not vary freely because large changes in isotopic inputs would induce secular trends in carbon reservoirs, which are not observed in the isotope record. We apply a geological carbon cycle model to all Earth history, tracking carbon isotopes in crustal, mantle, and ocean reservoirs. Our model is constrained by the carbon isotope record such that we can determine the extent to which large changes in organic burial are permitted. We find both constant organic burial and 3-5 fold increases in organic burial since 4.0 Ga can be reconciled with the carbon isotope record. Changes in the oxygen source flux thus need to be reconsidered as a possible contributor to Earth's oxygenation. [1] L. A. Derry, Organic carbon cycling and the lithosphere, in Treatise on

  10. Constrained systems described by Nambu mechanics

    International Nuclear Information System (INIS)

    Lassig, C.C.; Joshi, G.C.

    1996-01-01

    Using the framework of Nambu's generalised mechanics, we obtain a new description of constrained Hamiltonian dynamics, involving the introduction of another degree of freedom in phase space, and the necessity of defining the action integral on a world sheet. We also discuss the problem of quantizing Nambu mechanics. (authors). 5 refs

  11. 3Es System Optimization under Uncertainty Using Hybrid Intelligent Algorithm: A Fuzzy Chance-Constrained Programming Model

    Directory of Open Access Journals (Sweden)

    Jiekun Song

    2016-01-01

    Full Text Available Harmonious development of 3Es (economy-energy-environment system is the key to realize regional sustainable development. The structure and components of 3Es system are analyzed. Based on the analysis of causality diagram, GDP and industrial structure are selected as the target parameters of economy subsystem, energy consumption intensity is selected as the target parameter of energy subsystem, and the emissions of COD, ammonia nitrogen, SO2, and NOX and CO2 emission intensity are selected as the target parameters of environment system. Fixed assets investment of three industries, total energy consumption, and investment in environmental pollution control are selected as the decision variables. By regarding the parameters of 3Es system optimization as fuzzy numbers, a fuzzy chance-constrained goal programming (FCCGP model is constructed, and a hybrid intelligent algorithm including fuzzy simulation and genetic algorithm is proposed for solving it. The results of empirical analysis on Shandong province of China show that the FCCGP model can reflect the inherent relationship and evolution law of 3Es system and provide the effective decision-making support for 3Es system optimization.

  12. Electrochemical and anticorrosion behaviors of hybrid functionalized graphite nano-platelets/tripolyphosphate in epoxy-coated carbon steel

    International Nuclear Information System (INIS)

    Mohammadi, Somayeh; Shariatpanahi, Homeira; Taromi, Faramarz Afshar; Neshati, Jaber

    2016-01-01

    Highlights: • FGNP was combined with TPP to obtain a hybrid nano-particle. • TEM image showed uniform distribution of the hybrid nanoparticles in epoxy coating. • FGNP is a substrate for linking of TPP anions by hydrogen bonding. • FGNP as an accelerator, provides rapid iron phosphate passive film formation. • The hybrid nano-particle can provide long-term corrosion protection. - Abstract: Functionalized graphite nano-platelets (FGNP) were combined with tripolyphosphate (TPP) to gain a hybrid nano-particle (FGNP-TPP) with homogenous dispersion in epoxy, resulting in an excellent anti-corrosion coating for carbon steel substrate. Characterization analyses of the hybrid nano-particle were performed by FT-IR, SEM, XRD and TEM. TPP was linked to FGNP nano-particles by hydrogen bondings. Different epoxy coatings formulated with 1 wt.% of FGNP, FGNP-TPP and TPP were evaluated. Electrochemical investigations, salt spray and pull-off tests showed that the hybrid nano-particle can provide long-term corrosion protection compared to FGNP and TPP due to synergistic effect between FGNP as an accelerator and TPP as a corrosion inhibitor to produce a uniform and stable iron-phosphate passive film with high surface coverage.

  13. Electrochemical and anticorrosion behaviors of hybrid functionalized graphite nano-platelets/tripolyphosphate in epoxy-coated carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Somayeh, E-mail: somaye.mohammadi32@aut.ac.ir [Department of Chemistry, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Shariatpanahi, Homeira [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of); Taromi, Faramarz Afshar [Department of Polymer Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Neshati, Jaber [Corrosion Department, Research Institute of Petroleum Industry (RIPI), P.O. Box 18745-4163, Tehran (Iran, Islamic Republic of)

    2016-08-15

    Highlights: • FGNP was combined with TPP to obtain a hybrid nano-particle. • TEM image showed uniform distribution of the hybrid nanoparticles in epoxy coating. • FGNP is a substrate for linking of TPP anions by hydrogen bonding. • FGNP as an accelerator, provides rapid iron phosphate passive film formation. • The hybrid nano-particle can provide long-term corrosion protection. - Abstract: Functionalized graphite nano-platelets (FGNP) were combined with tripolyphosphate (TPP) to gain a hybrid nano-particle (FGNP-TPP) with homogenous dispersion in epoxy, resulting in an excellent anti-corrosion coating for carbon steel substrate. Characterization analyses of the hybrid nano-particle were performed by FT-IR, SEM, XRD and TEM. TPP was linked to FGNP nano-particles by hydrogen bondings. Different epoxy coatings formulated with 1 wt.% of FGNP, FGNP-TPP and TPP were evaluated. Electrochemical investigations, salt spray and pull-off tests showed that the hybrid nano-particle can provide long-term corrosion protection compared to FGNP and TPP due to synergistic effect between FGNP as an accelerator and TPP as a corrosion inhibitor to produce a uniform and stable iron-phosphate passive film with high surface coverage.

  14. Constraining the cause of the end-Guadalupian extinction with coupled records of carbon and calcium isotopes

    Science.gov (United States)

    Jost, A. B.; Mundil, R.; He, B.; Brown, S. T.; Altiner, D.; Sun, Y.; DePaolo, D. J.; Payne, J.

    2013-12-01

    A negative δ13C excursion in carbonate sediments from Guadalupian (Middle Permian) and Lopingian (Late Permian) stratigraphic sections has been interpreted to result from a large carbon cycle disturbance during end-Guadalupian extinction event (ca. 260 Ma). However, the carbon isotope data alone are insufficient to uniquely determine the type and magnitude of perturbations to the global carbon cycle. The carbon and calcium cycles are coupled via CaCO3 burial, so changes in calcium isotopes can be used to constrain the cause of a carbon isotope excursion. In this study, we present coupled carbon and calcium isotope records from three Guadalupian-Lopingian (G/L) sections in China and Turkey. Isotope records among our studied sections are inconsistent in both their δ13C and δ44/40Ca records. Similar inconsistencies in δ13C among sections occur across previously published datasets. Sections with large (>3‰) changes in δ13C either show evidence for diagenetic alteration or do not show δ13C and δ44/40Ca changes consistent with severe volcanic degassing from Emeishan or methane clathrate destabilization. We conclude that the large isotopic changes are more likely the result of local burial conditions or diagenetic effects, rather than a large carbon cycle disturbance. Perturbations to the global carbon and calcium cycles appear to have been much smaller across the G/L transition than across the subsequent Permian-Triassic boundary. This finding is consistent with recent paleobiological data showing that the end-Guadalupian extinction was much less severe than previously believed, and was indistinguishable in magnitude from background intervals. However, selective extinction of marine animals with passive respiratory physiology indicates that the G/L extinction cannot simply be due to background extinction or sampling failure, and that it was triggered by some environmental event. Therefore, any environmental event must have been small enough to not generate large

  15. Polyaniline-coated freestanding porous carbon nanofibers as efficient hybrid electrodes for supercapacitors

    Science.gov (United States)

    Tran, Chau; Singhal, Richa; Lawrence, Daniel; Kalra, Vibha

    2015-10-01

    Three-dimensional, free-standing, hybrid supercapacitor electrodes combining polyaniline (PANI) and porous carbon nanofibers (P-CNFs) were fabricated with the aim to integrate the benefits of both electric double layer capacitors (high power, cyclability) and pseudocapacitors (high energy density). A systematic investigation of three different electropolymerization techniques, namely, potentiodynamic, potentiostatic, and galvanostatic, for electrodeposition of PANI on freestanding carbon nanofiber mats was conducted. It was found that the galvanostatic method, where the current density is kept constant and can be easily controlled facilitates conformal and uniform coating of PANI on three-dimensional carbon nanofiber substrates. The electrochemical tests indicated that the PANI-coated P-CNFs exhibit excellent specific capacitance of 366 F g-1 (vs. 140 F g-1 for uncoated porous carbon nanofibers), 140 F cm-3 volumetric capacitance, and up to 2.3 F cm-2 areal capacitance at 100 mV s-1 scan rate. Such excellent performance is attributed to a thin and conformal coating of PANI achieved using the galvanostatic electrodeposition technique, which not only provides pseudocapacitance with high rate capability, but also retains the double-layer capacitance of the underlying P-CNFs.

  16. Efficient capture of CO2 over ordered micro-mesoporous hybrid carbon nanosphere

    Science.gov (United States)

    Chen, Changwei; Yu, Yanke; He, Chi; Wang, Li; Huang, Huang; Albilali, Reem; Cheng, Jie; Hao, Zhengping

    2018-05-01

    Four kinds of carbon-based adsorbents (micro-mesoporous hybrid carbon nanosphere and N-doped hollow carbon sphere with single-, double- or ruga-shell morphology) with different structural and textural properties were prepared and systematically studied in CO2 capture. All synthesized samples possess high specific surface area (828-910 m2 g-1), large pore volume (0.71-1.81 cm3 g-1), and different micropore contents varied from 2.1% to 46.4%. Amongst, the ordered micro-mesoporous carbon nanosphere (OM-CNS) exhibits the best adsorption performance with CO2 uptake as high as 3.01 mmol g-1 under conditions of 298 K and 1.0 bar, better than most of the reported CO2 adsorbents. The excellent CO2 adsorption capacity of OM-CNS can be reasonably attributed to the synergistic effect of ordered mesopore channels and abundant structural micropores which are beneficial for the diffusion and trapping of CO2 adsorbate. Moreover, the OM-CNS shows excellent CO2 trapping selectivity and superior stability and recyclability, which endow the OM-CNS as a promising and environmental-friendly adsorbent for CO2 capture and separation under practical conditions.

  17. Electrochemical supercapacitors based on novel hybrid materials made of carbon nanotubes and polyoxometalates

    Energy Technology Data Exchange (ETDEWEB)

    Cuentas-Gallegos, Ana Karina; Martinez-Rosales, Rosa; Rincon, Marina E. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Priv. Xochicalco s/n, Col. Centro, C.P. 62580 Temixco, Mor (Mexico); Baibarac, Mihaela; Gomez-Romero, Pedro [Instituto de Ciencia de Materiales de Barcelona, CSIC, Campus de la UAB, 08193 Bellaterra (Spain)

    2007-08-15

    We have characterized symmetric solid-state supercapacitors in swagelok cells using film electrodes made of novel hybrid materials based on multiwalled carbon nanotubes (CNT) and phosphomolybdate polyanion (Cs-PMo12) with PVA as binder. These hybrid materials were carried out by Cs-PMo12 adhesion onto previously functionalized CNT, in order to disperse both components at a molecular level and use Cs-PMo12 as energy density enhancer in supercapacitor cells. Our results show high capacitance values (up to 285 F/g at I = 200 mA/g) due to the contribution of Cs-PMo12, which was revealed on the higher energy density values compared to pure CNT electrodes. Additionally, good stability was observed during 500 charge-discharge cycles for most hybrid electrodes. These preliminary results show a new approach to enhance energy density of double layer supercapacitor cells through the introduction of Cs-PMo12, whereas from a material science point of view these materials are innovative, and open the way to search for diverse applications aside from supercapacitors (sensors, catalysts, photovoltaic cells, etc.). (author)

  18. Effect of ozone on the performance of a hybrid ceramic membrane-biological activated carbon process.

    Science.gov (United States)

    Guo, Jianning; Hu, Jiangyong; Tao, Yi; Zhu, Jia; Zhang, Xihui

    2014-04-01

    Two hybrid processes including ozonation-ceramic membrane-biological activated carbon (BAC) (Process A) and ceramic membrane-BAC (Process B) were compared to treat polluted raw water. The performance of hybrid processes was evaluated with the removal efficiencies of turbidity, ammonia and organic matter. The results indicated that more than 99% of particle count was removed by both hybrid processes and ozonation had no significant effect on its removal. BAC filtration greatly improved the removal of ammonia. Increasing the dissolved oxygen to 30.0 mg/L could lead to a removal of ammonia with concentrations as high as 7.80 mg/L and 8.69 mg/L for Processes A and B, respectively. The average removal efficiencies of total organic carbon and ultraviolet absorbance at 254 nm (UV254, a parameter indicating organic matter with aromatic structure) were 49% and 52% for Process A, 51% and 48% for Process B, respectively. Some organic matter was oxidized by ozone and this resulted in reduced membrane fouling and increased membrane flux by 25%-30%. However, pre-ozonation altered the components of the raw water and affected the microorganisms in the BAC, which may impact the removals of organic matter and nitrite negatively. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  19. Overall energy, exergy and carbon credit analysis by different type of hybrid photovoltaic thermal air collectors

    International Nuclear Information System (INIS)

    Agrawal, Sanjay; Tiwari, G.N.

    2013-01-01

    Highlights: ► Comparative study of PVT air collectors. ► CO 2 analysis of all type of PVT air collectors. ► Study of thermal energy, exergy gain and exergy efficiency. ► Exergy efficiency of unglazed hybrid PVT tiles air collector is most efficient. - Abstract: In this paper, comparative analysis of different type of photovoltaic thermal (PVT) air collector namely: (i) unglazed hybrid PVT tiles, (ii) glazed hybrid PVT tiles and (iii) conventional hybrid PVT air collectors have been carried out for the composite climate of Srinagar (India). The comparative study has been carried out in terms of overall thermal energy and exergy gain, exergy efficiency and carbon credit earned by different type of hybrid PVT air collectors. It has been observed that overall annual thermal energy and exergy gain of unglazed hybrid PVT tiles air collector is higher by 27% and 29.3% respectively as compared to glazed hybrid PVT tiles air collector and by 61% and 59.8% respectively as compared to conventional hybrid PVT air collector. It has also been observed that overall annual exergy efficiency of unglazed and glazed hybrid PVT tiles air collector is higher by 9.6% and 53.8% respectively as compared to conventional hybrid PVT air collector. On the basis of comparative study, it has been concluded that CO 2 emission reduction per annum on the basis of overall thermal energy gain of unglazed and glazed hybrid PVT tiles air collector is higher by 62.3% and 27.7% respectively as compared to conventional hybrid PVT air collector and on the basis of overall exergy gain it is 59.7% and 22.7%.

  20. Amperometric glucose biosensor based on glucose oxidase dispersed in multiwalled carbon nanotubes/graphene oxide hybrid biocomposite

    International Nuclear Information System (INIS)

    Palanisamy, Selvakumar; Cheemalapati, Srikanth; Chen, Shen-Ming

    2014-01-01

    An amperometric glucose biosensor based on enhanced and fast direct electron transfer (DET) of glucose oxidase (GOx) at enzyme dispersed multiwalled carbon nanotubes/graphene oxide (MWCNT/GO) hybrid biocomposite was developed. The fabricated hybrid biocomposite was characterized by transmission electron microscopy (TEM), Raman and infrared spectroscopy (IR). The TEM image of hybrid biocomposite reveals that a thin layer of GOx was covered on the surface of MWCNT/GO hybrid composite. IR results validate that the hybrid biocomposite was formed through the electrostatic interactions between GOx and MWCNT/GO hybrid composite. Further, MWCNT/GO hybrid composite has also been characterized by TEM and UV–visible spectroscopy. A pair of well-defined redox peak was observed for GOx immobilized at the hybrid biocomposite electrode than that immobilized at the MWCNT modified electrode. The electron transfer rate constant (K s ) of GOx at the hybrid biocomposite was calculated to be 11.22 s −1 . The higher K s value revealed that fast DET of GOx occurred at the electrode surface. Moreover, fabricated biosensor showed a good sensitivity towards glucose oxidation over a linear range 0.05–23.2 mM. The limit of detection (LOD) was estimated to be 28 μM. The good features of the proposed biosensor could be used for the accurate detection of glucose in the biological samples. - Highlights: • An amperometric glucose biosensor has been developed at MWCNT/GO hybrid biocomposite. • Enhanced and fast direct electron transfer kinetics of glucose oxidase has been achieved at hybrid biocomposite. • Hybrid biocomposite has been characterized by TEM, IR and Raman spectroscopy. • Highly sensitive and selective for glucose determination

  1. Amperometric glucose biosensor based on glucose oxidase dispersed in multiwalled carbon nanotubes/graphene oxide hybrid biocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Palanisamy, Selvakumar; Cheemalapati, Srikanth; Chen, Shen-Ming, E-mail: smchen78@ms15.hinet.net

    2014-01-01

    An amperometric glucose biosensor based on enhanced and fast direct electron transfer (DET) of glucose oxidase (GOx) at enzyme dispersed multiwalled carbon nanotubes/graphene oxide (MWCNT/GO) hybrid biocomposite was developed. The fabricated hybrid biocomposite was characterized by transmission electron microscopy (TEM), Raman and infrared spectroscopy (IR). The TEM image of hybrid biocomposite reveals that a thin layer of GOx was covered on the surface of MWCNT/GO hybrid composite. IR results validate that the hybrid biocomposite was formed through the electrostatic interactions between GOx and MWCNT/GO hybrid composite. Further, MWCNT/GO hybrid composite has also been characterized by TEM and UV–visible spectroscopy. A pair of well-defined redox peak was observed for GOx immobilized at the hybrid biocomposite electrode than that immobilized at the MWCNT modified electrode. The electron transfer rate constant (K{sub s}) of GOx at the hybrid biocomposite was calculated to be 11.22 s{sup −1}. The higher K{sub s} value revealed that fast DET of GOx occurred at the electrode surface. Moreover, fabricated biosensor showed a good sensitivity towards glucose oxidation over a linear range 0.05–23.2 mM. The limit of detection (LOD) was estimated to be 28 μM. The good features of the proposed biosensor could be used for the accurate detection of glucose in the biological samples. - Highlights: • An amperometric glucose biosensor has been developed at MWCNT/GO hybrid biocomposite. • Enhanced and fast direct electron transfer kinetics of glucose oxidase has been achieved at hybrid biocomposite. • Hybrid biocomposite has been characterized by TEM, IR and Raman spectroscopy. • Highly sensitive and selective for glucose determination.

  2. An Experimental Evaluation of Mechanical Properties of Hybrid Reinforcements

    Science.gov (United States)

    Sai Kumar, A.; Ganesan, G.; Karthikeyan, K.

    2017-07-01

    This paper presents the mechanical properties of unidirectional hybrid reinforcements formed from continuous fibres impregnated with a fibre binding material which are used for reinforcing the concrete. Recently FRP (Fibre Reinforced Polymer) manufacturers and suppliers have been increased all over the world because of the superior performance of FRP products in the construction industry. Its non-corrosive nature has turned the attention of many researchers to make several studies on different type of FRP products. Through a vast research, several standards also have been formulated. In this regard a new combination of FRP materials is tried in this paper and its properties have been derived. Carbon fibre and glass fibres fuse in this study to form a new hybrid rebar. The design properties such as tensile strength, tensile modulus, and compressive strength have been studied as per ASTM standards and it has been identified that the Hybrid rebar show a superior performance in comparison with GFRP (Glass FRP) and Steel rebars. This extraordinary performance of hybrid composite material increases the extensive engineering applications such as transport industry, aeronautics, naval, automotive industries.

  3. Flexible graphene/carbon nanotube hybrid papers chemical-reduction-tailored by gallic acid for high-performance electrochemical capacitive energy storages

    Science.gov (United States)

    Yao, Lu; Zhou, Chao; Hu, Nantao; Hu, Jing; Hong, Min; Zhang, Liying; Zhang, Yafei

    2018-03-01

    Mechanically robust graphene papers with both high gravimetric and volumetric capacitances are desired for high-performance energy storages. However, it's still a challenge to tailor the structure of graphene papers in order to meet this requirement. In this work, a kind of chemical-reduction-tailored mechanically-robust reduced graphene oxide/carbon nanotube hybrid paper has been reported for high-performance electrochemical capacitive energy storages. Gallic acid (GA), as an excellent reducing agent, was used to reduce graphene oxide. Through vacuum filtration of gallic acid reduced graphene oxide (GA-rGO) and carboxylic multiwalled carbon nanotubes (MWCNTs) aqueous suspensions, mechanically robust GA-rGO/MWCNTs hybrid papers were obtained. The resultant hybrid papers showed high gravimetric capacitance of 337.6 F g-1 (0.5 A g-1) and volumetric capacitance of 151.2 F cm-3 (0.25 A cm-3). In addition, the assembled symmetric device based on the hybrid papers exhibited high gravimetric capacitance of 291.6 F g-1 (0.5 A g-1) and volumetric capacitance of 136.6 F cm-3 (0.25 A cm-3). Meanwhile, it exhibited excellent rate capability and cycling stability. Above all, this chemical reduction tailoring technique and the resultant high-performance GA-rGO/MWCNTs hybrid papers give an insight for designing high-performance electrodes and hold a great potential in the field of energy storages.

  4. Edge-enriched, porous carbon-based, high energy density supercapacitors for hybrid electric vehicles.

    Science.gov (United States)

    Kim, Yong Jung; Yang, Cheol-Min; Park, Ki Chul; Kaneko, Katsumi; Kim, Yoong Ahm; Noguchi, Minoru; Fujino, Takeshi; Oyama, Shigeki; Endo, Morinobu

    2012-03-12

    Supercapacitors can store and deliver energy by a simple charge separation, and thus they could be an attractive option to meet transient high energy density in operating fuel cells and in electric and hybrid electric vehicles. To achieve such requirements, intensive studies have been carried out to improve the volumetric capacitance in supercapacitors using various types and forms of carbons including carbon nanotubes and graphenes. However, conventional porous carbons are not suitable for use as electrode material in supercapacitors for such high energy density applications. Here, we show that edge-enriched porous carbons are the best electrode material for high energy density supercapacitors to be used in vehicles as an auxiliary powertrain. Molten potassium hydroxide penetrates well-aligned graphene layers vertically and consequently generates both suitable pores that are easily accessible to the electrolyte and a large fraction of electrochemically active edge sites. We expect that our findings will motivate further research related to energy storage devices and also environmentally friendly electric vehicles. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Calcium carbonate-gold nanocluster hybrid spheres: synthesis and versatile application in immunoassays.

    Science.gov (United States)

    Peng, Juan; Feng, Li-Na; Zhang, Kui; Li, Xing-Hua; Jiang, Li-Ping; Zhu, Jun-Jie

    2012-04-23

    Fluorescent gold nanoclusters (AuNCs) were incorporated into porous calcium carbonate spheres through electrostatic interaction. The resulting CaCO(3)/AuNCs hybrid material exhibited interesting properties, such as porous structure, excellent biocompatibility, good water solubility, and degradability. These properties make the CaCO(3)/AuNCs hybrid material a promising template to assemble horseradish peroxidase/antibody conjugates (HRP-Ab(2)). By using CaCO(3)/AuNCs/HRP-Ab(2) bioconjugates as probes, a versatile immunosensor was developed for fluorescent and electrochemical detection of the cancer biomarker neuron-specific enolase (NSE). The detection limits of the sensor were 2.0 and 0.1 pg mL(-1) for fluorescent and electrochemical detection, respectively. The immunosensor shows high sensitivity and offers an alternative strategy for the detection of other proteins and DNA. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Role of organic soils in the world carbon cycle: problem definition and research needs

    Energy Technology Data Exchange (ETDEWEB)

    Armentano, T.V. (ed.)

    1979-01-01

    Findings and recommendations of the workshop on organic soils are summarized. The major finding of the workshop is that organic soils are important in the overall carbon budget. Histosols and gleysols, the major organic soil deposits of the world, normally sequester organic carbon fixed by plants. They may now be releasing enough carbon to account for nearly 10% of the annual rise in atmospheric content of CO/sub 2/. Current annual release of carbon from organic soils is estimated to fall within the range of 0.03 to 0.37 x 10/sup 9/ t, a release equivalent to 1.3% to 16% of the annual increase of carbon in the atmosphere. If half of the released carbon remains airborne, organic soils contribute 0.6% to 8.0% of the annual rise in CO/sub 2/. Uncertainties in data suggest the actual release could lie outside the range. Present annual releases of carbon from the Everglades Agricultural Area in Florida and the Sacramento-San Joaquin Valley in California are estimated at 0.017 x 10/sup 9/ tons. When combined with additional carbon release from other known drainage programs and the possibility of major drainage activity in the tropics, this figure suggests that the lower limit of the world estimate of carbon release from organic soils is too low. Annual sequestering of carbon by undrained organic soils has been estimated at about 0.045 x 10/sup 9/ tons. This estimate is based on only a few studies, however, and precision is probably no better than an order of magnitude. Several strategies for peatland management are available, including creation, preservation, functional designation, and use of wetlands for agriculture and energy supply.

  7. Carbon isotopic record from Upper Devonian carbonates at Dongcun in Guilin, southern China, supporting the world-wide pattern of carbon isotope excursions during Frasnian-Famennian transition

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Two positive δ13C excursions are presented in records from the Frasnian-Famennian (F-F) marine carbonate sediments in Europe, America, Africa, and Australia, having been considered as a worldwide pattern, and attributed to enhanced organic carbon burial during the F-F biological mass extinction. However, this worldwide pattern has not been revealed from the well-deposited Late Devonian sequences in southern China. In this paper, a detailed investigation has been made on the Late Devonian section at Dongcun, Guilin, southern China to constrain perturbations in δ13C of carbonates in the F-F deposited sequence. The result from this section also indicates two positive δ13C excursions during the F-F transition. The first excursion with an amplitude of 1.5‰ occurred at the bottom of linguiformis Zone, later than the early excursion existing in the Late rhenana Zone of the Late Devonian profiles in other continents, especially, in central Europe. This difference has been expected to be a result as conodont Palmatolepis linguiformis occurred earlier in southern China than other sites. The second excursion with an amplitude of 2.1‰ is located at the F-F boundary, same as the records from other continents. This result strongly supports the view that two carbon isotope positive excursions during the F-F transition are common in carbonate sediments, resulting from worldwide increases of organic carbon burial intensity.

  8. Leveraging 35 years of Pinus taeda research in the southeastern US to constrain forest carbon cycle predictions: regional data assimilation using ecosystem experiments

    Science.gov (United States)

    Quinn Thomas, R.; Brooks, Evan B.; Jersild, Annika L.; Ward, Eric J.; Wynne, Randolph H.; Albaugh, Timothy J.; Dinon-Aldridge, Heather; Burkhart, Harold E.; Domec, Jean-Christophe; Fox, Thomas R.; Gonzalez-Benecke, Carlos A.; Martin, Timothy A.; Noormets, Asko; Sampson, David A.; Teskey, Robert O.

    2017-07-01

    Predicting how forest carbon cycling will change in response to climate change and management depends on the collective knowledge from measurements across environmental gradients, ecosystem manipulations of global change factors, and mathematical models. Formally integrating these sources of knowledge through data assimilation, or model-data fusion, allows the use of past observations to constrain model parameters and estimate prediction uncertainty. Data assimilation (DA) focused on the regional scale has the opportunity to integrate data from both environmental gradients and experimental studies to constrain model parameters. Here, we introduce a hierarchical Bayesian DA approach (Data Assimilation to Predict Productivity for Ecosystems and Regions, DAPPER) that uses observations of carbon stocks, carbon fluxes, water fluxes, and vegetation dynamics from loblolly pine plantation ecosystems across the southeastern US to constrain parameters in a modified version of the Physiological Principles Predicting Growth (3-PG) forest growth model. The observations included major experiments that manipulated atmospheric carbon dioxide (CO2) concentration, water, and nutrients, along with nonexperimental surveys that spanned environmental gradients across an 8.6 × 105 km2 region. We optimized regionally representative posterior distributions for model parameters, which dependably predicted data from plots withheld from the data assimilation. While the mean bias in predictions of nutrient fertilization experiments, irrigation experiments, and CO2 enrichment experiments was low, future work needs to focus modifications to model structures that decrease the bias in predictions of drought experiments. Predictions of how growth responded to elevated CO2 strongly depended on whether ecosystem experiments were assimilated and whether the assimilated field plots in the CO2 study were allowed to have different mortality parameters than the other field plots in the region. We present

  9. Flexible solid-state supercapacitors based on carbon nanoparticles/MnO2 nanorods hybrid structure.

    Science.gov (United States)

    Yuan, Longyan; Lu, Xi-Hong; Xiao, Xu; Zhai, Teng; Dai, Junjie; Zhang, Fengchao; Hu, Bin; Wang, Xue; Gong, Li; Chen, Jian; Hu, Chenguo; Tong, Yexiang; Zhou, Jun; Wang, Zhong Lin

    2012-01-24

    A highly flexible solid-state supercapacitor was fabricated through a simple flame synthesis method and electrochemical deposition process based on a carbon nanoparticles/MnO(2) nanorods hybrid structure using polyvinyl alcohol/H(3)PO(4) electrolyte. Carbon fabric is used as a current collector and electrode (mechanical support), leading to a simplified, highly flexible, and lightweight architecture. The device exhibited good electrochemical performance with an energy density of 4.8 Wh/kg at a power density of 14 kW/kg, and a demonstration of a practical device is also presented, highlighting the path for its enormous potential in energy management. © 2011 American Chemical Society

  10. Sensitivity of tropical carbon to climate change constrained by carbon dioxide variability.

    Science.gov (United States)

    Cox, Peter M; Pearson, David; Booth, Ben B; Friedlingstein, Pierre; Huntingford, Chris; Jones, Chris D; Luke, Catherine M

    2013-02-21

    The release of carbon from tropical forests may exacerbate future climate change, but the magnitude of the effect in climate models remains uncertain. Coupled climate-carbon-cycle models generally agree that carbon storage on land will increase as a result of the simultaneous enhancement of plant photosynthesis and water use efficiency under higher atmospheric CO(2) concentrations, but will decrease owing to higher soil and plant respiration rates associated with warming temperatures. At present, the balance between these effects varies markedly among coupled climate-carbon-cycle models, leading to a range of 330 gigatonnes in the projected change in the amount of carbon stored on tropical land by 2100. Explanations for this large uncertainty include differences in the predicted change in rainfall in Amazonia and variations in the responses of alternative vegetation models to warming. Here we identify an emergent linear relationship, across an ensemble of models, between the sensitivity of tropical land carbon storage to warming and the sensitivity of the annual growth rate of atmospheric CO(2) to tropical temperature anomalies. Combined with contemporary observations of atmospheric CO(2) concentration and tropical temperature, this relationship provides a tight constraint on the sensitivity of tropical land carbon to climate change. We estimate that over tropical land from latitude 30° north to 30° south, warming alone will release 53 ± 17 gigatonnes of carbon per kelvin. Compared with the unconstrained ensemble of climate-carbon-cycle projections, this indicates a much lower risk of Amazon forest dieback under CO(2)-induced climate change if CO(2) fertilization effects are as large as suggested by current models. Our study, however, also implies greater certainty that carbon will be lost from tropical land if warming arises from reductions in aerosols or increases in other greenhouse gases.

  11. Bake hardening of ultra-fine grained low carbon steel produced by constrained groove pressing

    International Nuclear Information System (INIS)

    Alihosseini, H.; Dehghani, K.

    2012-01-01

    Highlights: ► BH of UFG low carbon steel sheets was studied. ► Three passes of CGP are used for producing of UFG sheets. ► Maximum BH was achieved to the UFG specimen pre-strained 8% by baking at 250 °C. - Abstract: In the present work, the bake hardening of ultra-fine grained low carbon steel was compared with that of its coarse-grain counterpart. The ultra-fine grained sheets were produced by applying three passes of constrained groove pressing resulting the grains of 260–270 nm. The microstructure of ultra-fine grain specimens were characterized using electron back-scatter diffraction technique. Then, the bake hardenability of ultra-fine grain and coarse-grain samples were compared by pre-straining to 4, 6 and 8% followed by baking at 150 °C and 250 °C for 20 min. The results show that in case of baking at 250 °C, there was an increase about 108%, 93%, and 72% in the bake hardening for 4%, 6% and 8% pre-strain, respectively. As for baking at 150 °C, these values were 170%, 168%, and 100%, respectively for 4%, 6% and 8% pre-strain. The maximum in bake hardenability (103 MPa) and final yield stress (563 MPa) were pertaining to the ultra-fine grain specimen pre-strained 8% followed by baking at 250 °C.

  12. Re-evaluation of forest biomass carbon stocks and lessons from the world's most carbon-dense forests.

    Science.gov (United States)

    Keith, Heather; Mackey, Brendan G; Lindenmayer, David B

    2009-07-14

    From analysis of published global site biomass data (n = 136) from primary forests, we discovered (i) the world's highest known total biomass carbon density (living plus dead) of 1,867 tonnes carbon per ha (average value from 13 sites) occurs in Australian temperate moist Eucalyptus regnans forests, and (ii) average values of the global site biomass data were higher for sampled temperate moist forests (n = 44) than for sampled tropical (n = 36) and boreal (n = 52) forests (n is number of sites per forest biome). Spatially averaged Intergovernmental Panel on Climate Change biome default values are lower than our average site values for temperate moist forests, because the temperate biome contains a diversity of forest ecosystem types that support a range of mature carbon stocks or have a long land-use history with reduced carbon stocks. We describe a framework for identifying forests important for carbon storage based on the factors that account for high biomass carbon densities, including (i) relatively cool temperatures and moderately high precipitation producing rates of fast growth but slow decomposition, and (ii) older forests that are often multiaged and multilayered and have experienced minimal human disturbance. Our results are relevant to negotiations under the United Nations Framework Convention on Climate Change regarding forest conservation, management, and restoration. Conserving forests with large stocks of biomass from deforestation and degradation avoids significant carbon emissions to the atmosphere, irrespective of the source country, and should be among allowable mitigation activities. Similarly, management that allows restoration of a forest's carbon sequestration potential also should be recognized.

  13. Re-evaluation of forest biomass carbon stocks and lessons from the world's most carbon-dense forests

    Science.gov (United States)

    Keith, Heather; Mackey, Brendan G.; Lindenmayer, David B.

    2009-01-01

    From analysis of published global site biomass data (n = 136) from primary forests, we discovered (i) the world's highest known total biomass carbon density (living plus dead) of 1,867 tonnes carbon per ha (average value from 13 sites) occurs in Australian temperate moist Eucalyptus regnans forests, and (ii) average values of the global site biomass data were higher for sampled temperate moist forests (n = 44) than for sampled tropical (n = 36) and boreal (n = 52) forests (n is number of sites per forest biome). Spatially averaged Intergovernmental Panel on Climate Change biome default values are lower than our average site values for temperate moist forests, because the temperate biome contains a diversity of forest ecosystem types that support a range of mature carbon stocks or have a long land-use history with reduced carbon stocks. We describe a framework for identifying forests important for carbon storage based on the factors that account for high biomass carbon densities, including (i) relatively cool temperatures and moderately high precipitation producing rates of fast growth but slow decomposition, and (ii) older forests that are often multiaged and multilayered and have experienced minimal human disturbance. Our results are relevant to negotiations under the United Nations Framework Convention on Climate Change regarding forest conservation, management, and restoration. Conserving forests with large stocks of biomass from deforestation and degradation avoids significant carbon emissions to the atmosphere, irrespective of the source country, and should be among allowable mitigation activities. Similarly, management that allows restoration of a forest's carbon sequestration potential also should be recognized. PMID:19553199

  14. Constraining the sources and cycling of dissolved organic carbon in a large oligotrophic lake using radiocarbon analyses

    Science.gov (United States)

    Zigah, Prosper K.; Minor, Elizabeth C.; McNichol, Ann P.; Xu, Li; Werne, Josef P.

    2017-07-01

    We measured the concentrations and isotopic compositions of solid phase extracted (SPE) dissolved organic carbon (DOC) and high molecular weight (HMW) DOC and their constituent organic components in order to better constrain the sources and cycling of DOC in a large oligotrophic lacustrine system (Lake Superior, North America). SPE DOC constituted a significant proportion (41-71%) of the lake DOC relative to HMW DOC (10-13%). Substantial contribution of 14C-depleted components to both SPE DOC (Δ14C = 25-43‰) and HMW DOC (Δ14C = 22-32‰) was evident during spring mixing, and depressed their radiocarbon values relative to the lake dissolved inorganic carbon (DIC; Δ14C ∼ 59‰). There was preferential removal of 14C-depleted (older) and thermally recalcitrant components from HMW DOC and SPE DOC in the summer. Contemporary photoautotrophic addition to HMW DOC was observed during summer stratification in contrast to SPE DOC, which decreased in concentration during stratification. Serial thermal oxidation radiocarbon analysis revealed a diversity of sources (both contemporary and older) within the SPE DOC, and also showed distinct components within the HMW DOC. The thermally labile components of HMW DOC were 14C-enriched and are attributed to heteropolysaccharides (HPS), peptides/amide and amino sugars (AMS) relative to the thermally recalcitrant components reflecting the presence of older material, perhaps carboxylic-rich alicyclic molecules (CRAM). The solvent extractable lipid-like fraction of HMW DOC was very 14C-depleted (as old as 1270-2320 14C years) relative to the carbohydrate-like and protein-like substances isolated by acid hydrolysis of HMW DOC. Our data constrain relative influences of contemporary DOC and old DOC, and DOC cycling in a modern freshwater ecosystem.

  15. Hierarchically structured graphene-carbon nanotube-cobalt hybrid electrocatalyst for seawater battery

    Science.gov (United States)

    Suh, Dong Hoon; Park, Sul Ki; Nakhanivej, Puritut; Kim, Youngsik; Hwang, Soo Min; Park, Ho Seok

    2017-12-01

    The design of cost-effective and highly active catalysts is a critical challenge. Inspired by the strong points of stability and conductivity of carbon nanotubes (CNTs), high catalytic activity of Co nanoparticles, and rapid ion diffusion and large accessible area of three-dimensional (3D) graphene, we demonstrate a novel strategy to construct a hierarchical hybrid structure consisting of Co/CoOx nanoparticles-incorporated CNT branches onto the 3D reduced graphene oxide (rGO) architecture. The surface-modified 3D rGO by steam activation process has a large surface area and abundant defect sites, which serve as active sites to uniformly grow Co/CoOx nanoparticles. Furthermore, the CNTs preserve their performance stably by encapsulating Co nanoparticles, while the uniformly decorated Co/CoOx nanoparticles exhibit superior electrocatalytic activity toward oxygen evolution/reduction reaction due to highly exposed active sites. Employing the hybrid particle electrocatalyst, the seawater battery operates stably at 0.01 mA cm-2 during 50 cycles, owing to the good electrocatalytic ability.

  16. Solution for state constrained optimal control problems applied to power split control for hybrid vehicles

    NARCIS (Netherlands)

    Keulen, van T.A.C.; Gillot, J.; Jager, de A.G.; Steinbuch, M.

    2014-01-01

    This paper presents a numerical solution for scalar state constrained optimal control problems. The algorithm rewrites the constrained optimal control problem as a sequence of unconstrained optimal control problems which can be solved recursively as a two point boundary value problem. The solution

  17. Hybrid carbon nanotube yarn artificial muscle inspired by spider dragline silk.

    Science.gov (United States)

    Chun, Kyoung-Yong; Hyeong Kim, Shi; Kyoon Shin, Min; Hoon Kwon, Cheong; Park, Jihwang; Tae Kim, Youn; Spinks, Geoffrey M; Lima, Márcio D; Haines, Carter S; Baughman, Ray H; Jeong Kim, Seon

    2014-01-01

    Torsional artificial muscles generating fast, large-angle rotation have been recently demonstrated, which exploit the helical configuration of twist-spun carbon nanotube yarns. These wax-infiltrated, electrothermally powered artificial muscles are torsionally underdamped, thereby experiencing dynamic oscillations that complicate positional control. Here, using the strategy spiders deploy to eliminate uncontrolled spinning at the end of dragline silk, we have developed ultrafast hybrid carbon nanotube yarn muscles that generated a 9,800 r.p.m. rotation without noticeable oscillation. A high-loss viscoelastic material, comprising paraffin wax and polystyrene-poly(ethylene-butylene)-polystyrene copolymer, was used as yarn guest to give an overdamped dynamic response. Using more than 10-fold decrease in mechanical stabilization time, compared with previous nanotube yarn torsional muscles, dynamic mirror positioning that is both fast and accurate is demonstrated. Scalability to provide constant volumetric torsional work capacity is demonstrated over a 10-fold change in yarn cross-sectional area, which is important for upscaled applications.

  18. Mechanical Behavior of Nanostructured Hybrids Based on Poly(Vinyl Alcohol/Bioactive Glass Reinforced with Functionalized Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    H. S. Mansur

    2012-01-01

    Full Text Available This study reports the synthesis and characterization of novel tridimensional porous hybrids based on PVA combined with bioactive glass and reinforced by chemically functionalized carbon nanotubes (CNT for potential use in bone tissue engineering. The functionalization of CNT was performed by introducing carboxylic groups in multiwall nanotubes. This process aimed at enhancing the affinity of CNTs with the water-soluble PVA polymer derived by the hydrogen bonds formed among alcohol (PVA and carboxylic groups (CNT–COOH. In the sequence, the CNT–COOH (0.25 wt% were used as the nanostructure modifier for the hybrid system based on PVA associated with the bioactive glass (BaG. The mechanical properties of the nanostructured hybrids reinforced with CNT–COOH were evaluated by axial compression tests, and they were compared to reference hybrid. The averaged yield stresses of macroporous hybrids were (2.3 ± 0.9 and (4.4 ± 1.0 MPa for the reference and the CNT reinforced materials, respectively. Moreover, yield strain and Young's modulus were significantly enhanced by about 30% for the CNT–COOH hybrids. Hence, as far as the mechanical properties are concerned, the results have clearly showed the feasibility of utilizing these new hybrids reinforced with functionalized CNT in repairing cancellous bone tissues.

  19. High-efficiency supercapacitor electrodes of CVD-grown graphenes hybridized with multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kalam, Amir Abul; Bae, Joon Ho [Dept. of Nano-physics, Gachon University, Seongnam (Korea, Republic of); Park, Soo Bin; Seo, Yong Ho [Nanotechnology and Advanced Material Engineering, HMC, and GRI, Sejong University, Seoul (Korea, Republic of)

    2015-08-15

    We demonstrate, for the first time, high-efficiency supercapacitors by utilizing chemical vapor deposition (CVD)-grown graphenes hybridized with multiwalled carbon nanotubes (CNTs). A single-layer graphene was grown by simple CVD growth method, and transferred to polyethylene terephthalate substrates. The bare graphenes were further hybridized with multiwalled CNTs by drop-coating CNTs on graphenes. The supercapacitors using bare graphenes and graphenes with CNTs revealed that graphenes with CNTs resulted in enhanced supercapacitor performances of 2.2- (the mass-specific capacitance) and 4.4-fold (the area-specific capacitance) of those of bare graphenes. Our strategy to improve electrochemical performance of CVD-grown graphenes is advantageous for large-scale graphene electrodes due to high electrical conductivity of CVD-grown graphenes and cost-effectiveness of using multiwalled CNTs as compared to conventional employment of single-walled CNTs.

  20. Label-free detection of DNA hybridization using carbon nanotube network field-effect transistors

    Science.gov (United States)

    Star, Alexander; Tu, Eugene; Niemann, Joseph; Gabriel, Jean-Christophe P.; Joiner, C. Steve; Valcke, Christian

    2006-01-01

    We report carbon nanotube network field-effect transistors (NTNFETs) that function as selective detectors of DNA immobilization and hybridization. NTNFETs with immobilized synthetic oligonucleotides have been shown to specifically recognize target DNA sequences, including H63D single-nucleotide polymorphism (SNP) discrimination in the HFE gene, responsible for hereditary hemochromatosis. The electronic responses of NTNFETs upon single-stranded DNA immobilization and subsequent DNA hybridization events were confirmed by using fluorescence-labeled oligonucleotides and then were further explored for label-free DNA detection at picomolar to micromolar concentrations. We have also observed a strong effect of DNA counterions on the electronic response, thus suggesting a charge-based mechanism of DNA detection using NTNFET devices. Implementation of label-free electronic detection assays using NTNFETs constitutes an important step toward low-cost, low-complexity, highly sensitive and accurate molecular diagnostics. hemochromatosis | SNP | biosensor

  1. High-efficiency supercapacitor electrodes of CVD-grown graphenes hybridized with multiwalled carbon nanotubes

    International Nuclear Information System (INIS)

    Kalam, Amir Abul; Bae, Joon Ho; Park, Soo Bin; Seo, Yong Ho

    2015-01-01

    We demonstrate, for the first time, high-efficiency supercapacitors by utilizing chemical vapor deposition (CVD)-grown graphenes hybridized with multiwalled carbon nanotubes (CNTs). A single-layer graphene was grown by simple CVD growth method, and transferred to polyethylene terephthalate substrates. The bare graphenes were further hybridized with multiwalled CNTs by drop-coating CNTs on graphenes. The supercapacitors using bare graphenes and graphenes with CNTs revealed that graphenes with CNTs resulted in enhanced supercapacitor performances of 2.2- (the mass-specific capacitance) and 4.4-fold (the area-specific capacitance) of those of bare graphenes. Our strategy to improve electrochemical performance of CVD-grown graphenes is advantageous for large-scale graphene electrodes due to high electrical conductivity of CVD-grown graphenes and cost-effectiveness of using multiwalled CNTs as compared to conventional employment of single-walled CNTs

  2. Hybrid Instantaneous Wave-Free Ratio–Fractional Flow Reserve versus Fractional Flow Reserve in the Real World

    Directory of Open Access Journals (Sweden)

    Kara Shuttleworth

    2017-05-01

    Full Text Available BackgroundThe instantaneous wave-free ratio (iFR is a novel method to assess the ischemic potential of coronary artery stenoses. Clinical trial data have shown that iFR has acceptable diagnostic agreement with fractional flow reserve (FFR, the reference standard for the functional assessment of coronary stenoses. This study compares iFR measurements with FFR measurements in a real world, single-center setting.Methods and resultsInstantaneous wave-free ratio and FFR were measured in 50 coronary artery lesions in 42 patients, with FFR ≤ 0.8 classified as functionally significant. An iFR-only technique, using a treatment cut-off value, iFR ≤ 0.89, provided a classification agreement of 84% with FFR ≤ 0.80. Use of a hybrid iFR–FFR technique, incorporating FFR measurement for lesions within the iFR gray zone of 0.86–0.93, would improve classification agreement with FFR to 94%, with diagnosis achieved without the need for hyperemia in 57% patients.ConclusionThis study in a real-world setting demonstrated good classification agreement between iFR and FFR. Use of a hybrid iFR–FFR technique would achieve high diagnostic accuracy while minimizing adenosine use, compared with routine FFR.

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

    Science.gov (United States)

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

    2018-05-01

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

  4. Optimal control of hybrid vehicles

    CERN Document Server

    Jager, Bram; Kessels, John

    2013-01-01

    Optimal Control of Hybrid Vehicles provides a description of power train control for hybrid vehicles. The background, environmental motivation and control challenges associated with hybrid vehicles are introduced. The text includes mathematical models for all relevant components in the hybrid power train. The power split problem in hybrid power trains is formally described and several numerical solutions detailed, including dynamic programming and a novel solution for state-constrained optimal control problems based on Pontryagin’s maximum principle.   Real-time-implementable strategies that can approximate the optimal solution closely are dealt with in depth. Several approaches are discussed and compared, including a state-of-the-art strategy which is adaptive for vehicle conditions like velocity and mass. Two case studies are included in the book: ·        a control strategy for a micro-hybrid power train; and ·        experimental results obtained with a real-time strategy implemented in...

  5. Hybrid metal grid-polymer-carbon nanotube electrodes for high luminance organic light emitting diodes

    International Nuclear Information System (INIS)

    Sam, F Laurent M; Dabera, G Dinesha M R; Lai, Khue T; Mills, Christopher A; Rozanski, Lynn J; Silva, S Ravi P

    2014-01-01

    Organic light emitting diodes (OLEDs) incorporating grid transparent conducting electrodes (TCEs) with wide grid line spacing suffer from an inability to transfer charge carriers across the gaps in the grids to promote light emission in these areas. High luminance OLEDs fabricated using a hybrid TCE composed of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS PH1000) or regioregular poly(3-hexylthiophene)-wrapped semiconducting single-walled carbon nanotubes (rrP3HT-SWCNT) in combination with a nanometre thin gold grid are reported here. OLEDs fabricated using the hybrid gold grid/PH1000 TCE have a luminance of 18 000 cd m −2 at 9 V; the same as the reference indium tin oxide (ITO) OLED. The gold grid/rrP3HT-SWCNT OLEDs have a lower luminance of 8260 cd m −2 at 9 V, which is likely due to a rougher rrP3HT-SWCNT surface. These results demonstrate that the hybrid gold grid/PH1000 TCE is a promising replacement for ITO in future plastic electronics applications including OLEDs and organic photovoltaics. For applications where surface roughness is not critical, e.g. electrochromic devices or discharge of static electricity, the gold grid/rrP3HT-SWCNT hybrid TCE can be employed. (paper)

  6. Study of tribological properties of natural rubber containing carbon nanotubes and carbon black as hybrid fillers

    Science.gov (United States)

    Harea, Evghenii; Stoček, Radek; Storozhuk, Liudmyla; Sementsov, Yurii; Kartel, Nikolai

    2018-04-01

    Dry friction and wear properties of natural rubber (NR), containing multi-walled carbon nanotubes (MWCNT) and carbon black (CB), were investigated. Natural rubber (NR)-based composites containing all common additives and curatives, and a fixed amount (30 phr—parts per 100 rubber by weight) of hybrid fillers (MWCNT x + CB30-x ) were prepared by simple mixing procedure and tested. The main goal was to study the behaviours of composites at different tribological testing conditions, such as friction speed and normal load. It was found that with an increase of concentration of MWCNT from x = 0 phr to x = 5 phr in studied composites, there was a decrease in the coefficient of friction (COF) with no significant change in wear in the framework of each used combination of testing parameters. Generally, higher friction speed at certain normal force led to the increase of COF of all the samples and wear reflected deliberate value fluctuation. Also, it was established that considerable growth of wear and unexpected reducing of friction coefficient ensued from increasing of applied load for every fixed sliding speed.

  7. Flame Retardancy Effects of Graphene Nanoplatelet/Carbon Nanotube Hybrid Membranes on Carbon Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Dongxian Zhuo

    2013-01-01

    Full Text Available Carbon nanotube/graphene nanoplatelet (MWCNT/GNP hybrid membranes with lower liquid permeability and better barrier effect compared to MWCNT membranes were successfully synthesized by vacuum filtering. Their morphologies, water permeability, and pore structures were characterized by a scanning electron microscope (SEM and nitrogen adsorption isotherms. Furthermore, MWCNT/GNP membranes were used to improve the flame retardancy of carbon fiber reinforced polymer (CFRP composites, and the influence of weight percentage of GNPs on the permeability and flame retardancy of MWCNT/GNP membranes was systematically investigated. Results show that incorporation of MWCNT/GNP membranes on CFRP composite plates can remarkably improve the flame retardancy of CFRP composites. Specifically, the incorporation of hierarchical MWCNT/GNP membrane with 7.5 wt% of GNP displays a 35% reduction in the peak heat release rate (PHRR for a CFRP composite plate with the epoxy as matrix and a 11% reduction in PHRR compared with the incorporation of MWCNT membrane only. A synergistic flame retarding mechanism is suggested to be attributed to these results, which includes controlling the pore size and penetrative network structure.

  8. A chance-constrained stochastic approach to intermodal container routing problems.

    Science.gov (United States)

    Zhao, Yi; Liu, Ronghui; Zhang, Xi; Whiteing, Anthony

    2018-01-01

    We consider a container routing problem with stochastic time variables in a sea-rail intermodal transportation system. The problem is formulated as a binary integer chance-constrained programming model including stochastic travel times and stochastic transfer time, with the objective of minimising the expected total cost. Two chance constraints are proposed to ensure that the container service satisfies ship fulfilment and cargo on-time delivery with pre-specified probabilities. A hybrid heuristic algorithm is employed to solve the binary integer chance-constrained programming model. Two case studies are conducted to demonstrate the feasibility of the proposed model and to analyse the impact of stochastic variables and chance-constraints on the optimal solution and total cost.

  9. Efficient cold cathode emission in crystalline-amorphous hybrid: Study on carbon nanotube-cadmium selenide system

    Science.gov (United States)

    Sarkar, S.; Banerjee, D.; Das, N. S.; Ghorai, U. K.; Sen, D.; Chattopadhyay, K. K.

    2018-03-01

    Cadmium Selenide (CdSe) quantum dot (QD) decorated amorphous carbon nanotubes (a-CNTs) hybrids have been synthesized by simple chemical process. The samples were characterized by field emission scanning and transmission electron microscopy, Fourier transformed infrared spectroscopy, Raman and UV-Vis spectroscopy. Lattice image obtained from transmission electron microscopic study confirms the successful attachment of CdSe QDs. It is seen that hybrid samples show an enhanced cold emission properties with good stability. The results have been explained in terms of increased roughness, more numbers of emitting sites and favorable band bending induced electron transport. ANSYS software based calculation has also supported the result. Also a first principle based study has been done which shows that due to the formation of hybrid structure there is a profound upward shift in the Fermi level, i.e. a decrease of work function, which is believed to be another key reason for the observed improved field emission performance.

  10. Photocatalytic degradation of different chromophoric dyes in aqueous phase using La and Mo doped TiO{sub 2} hybrid carbon spheres

    Energy Technology Data Exchange (ETDEWEB)

    Raza, Waseem; Haque, M.M. [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India); Muneer, M., E-mail: m.muneer.ch@amu.ac.in [Department of Chemistry, Aligarh Muslim University, Aligarh 202002 (India); Fleisch, M.; Hakki, A.; Bahnemann, D. [Institut fuer Technische Chemie, Leibniz Universität Hannover, Callinstrasse 3, D-30167 Hannover (Germany)

    2015-05-25

    Highlights: • La and Mo doped TiO{sub 2} hybrid carbon spheres have been synthesized using hydrothermal method. • The characterization of La and Mo doped TiO{sub 2} hybrid carbon spheres uniform morphology having anatase phase and good structural stability. • TiO{sub 2} hybrid carbon spheres with dopant concentration of 2.0% (La) and 1.5% (Mo) showed the highest photocatalytic activity as compared to the other dopant concentrations for the degradation of all the dyes under investigation. - Abstract: La and Mo-doped TiO{sub 2} coated carbon spheres have been synthesized using the hydrothermal method. The prepared materials were characterized by standard analytical techniques, X-ray diffraction (XRD), UV–Vis spectrophotometry, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. The XRD and Raman spectroscopic analysis showed that the particles are in anatase phase. The EDX and SEM images showed that La/Mo-doped TiO{sub 2} are present on the surface of the carbon spheres. The photocatalytic activity of the synthesized particles were tested by studying the degradation of three different chromophoric dyes, i.e., Acid Yellow 29 (azo dye), Coomassie Brilliant Blue G250 (triphenylmethane dye) and Acid Green 25 (anthraquinone dye) as a function of time on irradiation in aqueous suspension. TiO{sub 2} particle with dopant concentration of 2.0% La and 1.5% Mo showed the highest photocatalytic activity as compared to the other dopant concentrations for the degradation of all the dyes under investigation.

  11. Amorphous Mn oxide-ordered mesoporous carbon hybrids as a high performance electrode material for supercapacitors.

    Science.gov (United States)

    Nam, Inho; Kim, Nam Dong; Kim, Gil-Pyo; Park, Junsu; Yi, Jongheop

    2012-07-01

    A supercapacitor has the advantages of both the conventional capacitors and the rechargeable batteries. Mn oxide is generally recognized one of the potential materials that can be used for a supercapacitor, but its low conductivity is a limiting factor for electrode materials. In this study, a hybrid of amorphous Mn oxide (AMO) and ordered mesoporous carbon (OMC) was prepared and characterized using X-ray diffraction, transmission electron microscopy, N2/77 K sorption techniques, and electrochemical analyses. The findings indicate that the electrochemical activities of Mn oxide were facilitated when it was in the hybrid state because OMC acted as a pathway for both the electrolyte ions and the electrons due to the characteristics of the ordered mesoporous structure. The ordered mesoporous structure of OMC was well maintained even after hybridization with amorphous Mn oxide. The electrochemical-activity tests revealed that the AMO/OMC hybrid had a higher specific capacitance and conductivity than pure Mn oxide. In the case where the Mn/C weight ratio was 0.75, the composite showed a high capacitance of 153 F/g, which was much higher than that for pure Mn oxide, due to the structural effects of OMC.

  12. Isothermal and hygrothermal agings of hybrid glass fiber/carbon fiber composite

    Science.gov (United States)

    Barjasteh, Ehsan

    anhydride/epoxy network used in composite-reinforced conductor cables was investigated to determine the extent of thermal oxidative (surface effect) and non-oxidative (bulk effect) degradation. Thermal oxidation tests were performed in air-circulating and vacuum ovens at 180°C and 200ºC (the maximum emergency temperature for ACCC conductors). The extent of oxidation during aging was determined by monitoring the thickness of the oxidized layer. Results showed that the oxidized layer thickness did not increase monotonically as a function of exposure time, and even decreased for a limited period of time. A phenomenological reaction-diffusion model was implemented to predict the thickness of oxidized layer, and the calculated results were compared with measurements for aging times up to 10,000 hours. The accuracy of the reaction-diffusion-based thickness values for the isothermally aged epoxy specimen was affected by the permeability properties of the oxidized material, and to a lesser extent by the degree of oxidation. The diffusivity varied because of changes in the density of the oxidized layer, the macro-void content, crack formation, and the molecular structures. To investigate the effects on diffusivity, the morphology of the oxidized layer and the void content was monitored over time. In addition, the density of the oxidized specimens was calculated by direct measurements of volume and weight during exposure. An empirically based volume-loss model was developed to predict the changes in volume of the specimen as a function of aging times and hence to predict the effects on the oxidized layer thickness. Volume-loss measurements provide an indication of material degradation by demonstrating a direct measurement of shrinkage rates and insight into crack initiation, as opposed to typical weight-loss measurements that provide no insight into material failure. Thermal oxidation of a unidirectional carbon-fiber/glass-fiber hybrid composite was also investigated in this study

  13. Nanocomposite metal amorphous-carbon thin films deposited by hybrid PVD and PECVD technique.

    Science.gov (United States)

    Teixeira, V; Soares, P; Martins, A J; Carneiro, J; Cerqueira, F

    2009-07-01

    Carbon based films can combine the properties of solid lubricating graphite structure and hard diamond crystal structure, i.e., high hardness, chemical inertness, high thermal conductivity and optical transparency without the crystalline structure of diamond. Issues of fundamental importance associated with nanocarbon coatings are reducing stress, improving adhesion and compatibility with substrates. In this work new nanocomposite coatings with improved toughness based in nanocrystalline phases of metals and ceramics embedded in amorphous carbon matrix are being developed within the frame of a research project: nc-MeNxCy/a-C(Me) with Me = Mo, Si, Al, Ti, etc. Carbide forming metal/carbon (Me/C) composite films with Me = Mo, W or Ti possess appropriate properties to overcome the limitation of pure DLC films. These novel coating architectures will be adopted with the objective to decrease residual stress, improve adherence and fracture toughness, obtain low friction coefficient and high wear-resistance. Nanocomposite DLC's films were deposited by hybrid technique using a PVD-Physically Vapor Deposition (magnetron sputtering) and Plasma Enhanced Chemical Vapor Deposition (PECVD), by the use of CH4 gas. The parameters varied were: deposition time, substrate temperature (180 degrees C) and dopant (Si + Mo) of the amorphous carbon matrix. All the depositions were made on silicon wafers and steel substrates precoated with a silicon inter-layer. The characterisation of the film's physico-mechanical properties will be presented in order to understand the influence of the deposition parameters and metal content used within the a-C matrix in the thin film properties. Film microstructure and film hybridization state was characterized by Raman Spectroscopy. In order to characterize morphology SEM and AFM will be used. Film composition was measured by Energy-Dispersive X-ray analysis (EDS) and by X-ray photoelectron spectroscopy (XPS). The contact angle for the produced DLC's on

  14. Using n-alkane records to constrain carbon cycle - hydrological cycle coupling: Case study from the Northern Hemisphere mid-latitudes during the PETM

    Science.gov (United States)

    Krishnan, S.; Pagani, M.; Tipple, B. J.

    2010-12-01

    The early Eocene was a warmer world compared to the present and is characterized by rising temperatures interspersed with rapid hyperthermal events. During the largest of these rapid warming events; the Paleocene-Eocene Thermal Maximum (PETM), proxy records suggest that sea surface temperatures (SST) rose by 3-5 deg. C in the tropics (Zachos et al., 2003, Tripati and Elderfield, 2004), >5 deg. C in the Arctic (Sluijs et al., 2006) and perhaps has high as 9 deg. C in some sub-Antarctic regions (Kennett and Stott, 1991; Thomas et al., 1999). This warming is believed to be the result of massive input of 13C-depleted carbon into the ocean-atmosphere system, evidenced by the large negative carbon isotope excursion (CIE) and carbonate dissolution associated with the event. However, there are several questions regarding the exact mechanism of warming and feedbacks between the carbon cycle and climate. Did climate shift prior to the main event that led to the release of isotopically light carbon? Do we observe consistent leads or lags between changes in carbon isotopes and hydrological conditions during warm intervals? This study aims to reconstruct hydrological changes in the in the Northern Hemisphere mid-latitudes during the PETM using terrestrial biomarkers. Terrestrial biomarkers, such leaf-wax lipids stored in sediments, have the unique advantage of recording carbon and hydrogen isotopic compositions of atmospheric CO2 (modified by plant fractionation) and precipitation (modified by plant fractionation and evapotranspiration), allowing evaluation of the relative timing of carbon and hydrogen isotopic (i.e., climate) shifts. In this study, we compile and present three mid-latitude PETM records from the Northern Hemisphere, i.e. Alamedilla (Spain), Cicogna and Forada (Italy). The Cicogna and Forada sections are located in the Belluno basin (~12 km apart). Preliminary results do not indicate any significant pre-excursion hydrogen isotope changes at Cicogna, while at

  15. Investigation of the Mechanical Properties of Hybrid Carbon-Hemp Laminated Composites Used as Thermal Insulation for Different Industrial Applications

    Directory of Open Access Journals (Sweden)

    M. L. Scutaru

    2014-04-01

    Full Text Available Carbon-hemp composite laminate provides good thermal properties. For this reason this type of material is presently being used for various applications like insulator for airplanes, spaceships, nuclear reactors, and so forth. Unfortunately their mechanical properties are less studied. These characteristics are very important since they should be guaranteed also for important mechanical stress in addition to the thermal one. The present paper presents a study regarding the impact testing of some hybrid composite laminate panels based on polyester resin reinforced with both carbon and hemp fabric. The effects of different impact speeds on the mechanical behavior of these panels have been analyzed. The paper lays stress on the characterization of this hybrid composite laminate regarding the impact behavior of these panels by dropping a weight with low velocity.

  16. Tracking global carbon revenues: A survey of carbon taxes versus cap-and-trade in the real world

    International Nuclear Information System (INIS)

    Carl, Jeremy; Fedor, David

    2016-01-01

    We investigate the current use of public revenues which are generated through both carbon taxes and cap-and-trade systems. More than $28.3 billion in government “carbon revenues” are currently collected each year in 40 countries and another 16 states or provinces around the world. Of those revenues, 27% ($7.8 billion) are used to subsidize “green” spending in energy efficiency or renewable energy; 26% ($7.4 billion) go toward state general funds; and 36% ($10.1 billion) are returned to corporate or individual taxpayers through paired tax cuts or direct rebates. Cap-and-trade systems ($6.57 billion in total public revenue) earmark a larger share of revenues for “green” spending (70%), while carbon tax systems ($21.7 billion) more commonly refund revenues or otherwise direct them towards government general funds (72% of revenues). Drawing from an empirical dataset, we also identify various trends in systems’ use of “carbon revenues” in terms of the total revenues collected annually per capita in each jurisdiction and offer commensurate qualitative observations on carbon policy design choices. - Highlights: •We analyze public revenue generated from global carbon tax and cap-and-trade systems. •70% of cap-and-trade revenues ($4.60 billion) are earmarked for “green spending”. •72% of carbon tax revenues ($15.6 billion) are refunded or used in general funds. •Revenues per capita vary widely and are a useful qualitative explanatory variable.

  17. Grafting the surface of carbon nanotubes and carbon black with the chemical properties of hyperbranched polyamines

    Science.gov (United States)

    Morales-Lara, Francisco; Domingo-García, María; López-Garzón, Rafael; Luz Godino-Salido, María; Peñas-Sanjuán, Antonio; López-Garzón, F. Javier; Pérez-Mendoza, Manuel; Melguizo, Manuel

    2016-01-01

    Controlling the chemistry on the surface of new carbon materials is a key factor to widen the range of their applicability. In this paper we show a grafting methodology of polyalkylamines to the surface of carbon nanomaterials, in particular, carbon nanotubes and a carbon black. The aim of this work is to reach large degrees of covalent functionalization with hyperbranched polyethyleneimines (HBPEIs) and to efficiently preserve the strong chelating properties of the HBPEIs when they are fixed to the surface of these carbon materials. This functionalization opens new possibilities of using these carbon nanotubes-based hybrids. The results show that the HBPEIs are covalently attached to the carbon materials, forming hybrids. These hybrids emerge from the reaction of amine functions of the HBPEIs with carbonyls and carboxylic anhydrides of the carbon surface which become imine and imide bonds. Thus, due to the nature of these bonds, the pre-oxidized samples with relevant number of C=O groups showed an increase in the degree of functionalization with the HBPEIs. Furthermore, both the acid-base properties and the coordination capacity for metal ions of the hybrids are equivalent to that of the free HBPEIs in solution. This means that the chemical characteristics of the HBPEIs have been efficiently transferred to the hybrids. To reach this conclusion we have developed a novel procedure to assess the acid-base and the coordination properties of the hybrids (solids) by means of potentiometric titration. The good agreement of the values obtained for the hybrids and for the free HBPEIs in aqueous solution supports the reliability of the procedure. Moreover, the high capacity of the hybrids to capture Ni2+ by complexation opens new possibilities of using these hybrids to capture high-value metal ions such as Pd2+ and Pt2+.

  18. Fabrication of graphene foam supported carbon nanotube/polyaniline hybrids for high-performance supercapacitor applications

    International Nuclear Information System (INIS)

    Yang, Hongxia; Wang, Nan; Xu, Qun; Chen, Zhimin; Ren, Yumei; Razal, Joselito M; Chen, Jun

    2014-01-01

    A large-scale, high-powered energy storage system is crucial for addressing the energy problem. The development of high-performance materials is a key issue in realizing the grid-scale applications of energy-storage devices. In this work, we describe a simple and scalable method for fabricating hybrids (graphene-pyrrole/carbon nanotube-polyaniline (GPCP)) using graphene foam as the supporting template. Graphene-pyrrole (G-Py) aerogels are prepared via a green hydrothermal route from two-dimensional materials such as graphene sheets, while a carbon nanotube/polyaniline (CNT/PANI) composite dispersion is obtained via the in situ polymerization method. The functional nanohybrid materials of GPCP can be assembled by simply dipping the prepared G-py aerogels into the CNT/PANI dispersion. The morphology of the obtained GPCP is investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), which revealed that the CNT/PANI was uniformly deposited onto the surfaces of the graphene. The as-synthesized GPCP maintains its original three-dimensional hierarchical porous architecture, which favors the diffusion of the electrolyte ions into the inner region of the active materials. Such hybrid materials exhibit significant specific capacitance of up to 350 F g −1 , making them promising in large-scale energy-storage device applications. (paper)

  19. Investigation of the interfacial properties of polyurethane/carbon nanotube hybrid composites: A molecular dynamics study

    Science.gov (United States)

    Goclon, Jakub; Panczyk, Tomasz; Winkler, Krzysztof

    2018-03-01

    Considering the varied applications of hybrid polymer/carbon nanotube composites and the constant progress in the synthesis methods of such materials, we report a theoretical study of interfacial layer formation between pristine single-wall carbon nanotubes (SWCNTs) and polyurethane (PU) using molecular dynamic simulations. We vary the SWCNT diameter and the number of PU chains to examine various PU-SWCNT interaction patterns. Our simulations indicate the important role of intra-chain forces in PU. No regular polymeric structures could be identified on the carbon nanotube surface during the simulations. We find that increasing the SWCNT diameter results in stronger polymer binding. However, higher surface loadings of PU lead to stronger interpenetration by the polymeric segments; this effect is more apparent for SWCNTs with small diameters. Our core finding is that the attached PU binds most strongly to the carbon nanotubes with the largest diameters. Polymer dynamics reveal the loose distribution of PU chains in these systems.

  20. 16th International Conference on Hybrid Intelligent Systems and the 8th World Congress on Nature and Biologically Inspired Computing

    CERN Document Server

    Haqiq, Abdelkrim; Alimi, Adel; Mezzour, Ghita; Rokbani, Nizar; Muda, Azah

    2017-01-01

    This book presents the latest research in hybrid intelligent systems. It includes 57 carefully selected papers from the 16th International Conference on Hybrid Intelligent Systems (HIS 2016) and the 8th World Congress on Nature and Biologically Inspired Computing (NaBIC 2016), held on November 21–23, 2016 in Marrakech, Morocco. HIS - NaBIC 2016 was jointly organized by the Machine Intelligence Research Labs (MIR Labs), USA; Hassan 1st University, Settat, Morocco and University of Sfax, Tunisia. Hybridization of intelligent systems is a promising research field in modern artificial/computational intelligence and is concerned with the development of the next generation of intelligent systems. The conference’s main aim is to inspire further exploration of the intriguing potential of hybrid intelligent systems and bio-inspired computing. As such, the book is a valuable resource for practicing engineers /scientists and researchers working in the field of computational intelligence and artificial intelligence.

  1. Trends in PDE constrained optimization

    CERN Document Server

    Benner, Peter; Engell, Sebastian; Griewank, Andreas; Harbrecht, Helmut; Hinze, Michael; Rannacher, Rolf; Ulbrich, Stefan

    2014-01-01

    Optimization problems subject to constraints governed by partial differential equations (PDEs) are among the most challenging problems in the context of industrial, economical and medical applications. Almost the entire range of problems in this field of research was studied and further explored as part of the Deutsche Forschungsgemeinschaft (DFG) priority program 1253 on “Optimization with Partial Differential Equations” from 2006 to 2013. The investigations were motivated by the fascinating potential applications and challenging mathematical problems that arise in the field of PDE constrained optimization. New analytic and algorithmic paradigms have been developed, implemented and validated in the context of real-world applications. In this special volume, contributions from more than fifteen German universities combine the results of this interdisciplinary program with a focus on applied mathematics.   The book is divided into five sections on “Constrained Optimization, Identification and Control”...

  2. Metal/Carbon Hybrid Nanostructures Produced from Plasma-Enhanced Chemical Vapor Deposition over Nafion-Supported Electrochemically Deposited Cobalt Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohammad Islam

    2018-04-01

    Full Text Available In this work, we report development of hybrid nanostructures of metal nanoparticles (NP and carbon nanostructures with strong potential for catalysis, sensing, and energy applications. First, the etched silicon wafer substrates were passivated for subsequent electrochemical (EC processing through grafting of nitro phenyl groups using para-nitrobenzene diazonium (PNBT. The X-ray photoelectron spectroscope (XPS and atomic force microscope (AFM studies confirmed presence of few layers. Cobalt-based nanoparticles were produced over dip or spin coated Nafion films under different EC reduction conditions, namely CoSO4 salt concentration (0.1 M, 1 mM, reduction time (5, 20 s, and indirect or direct EC reduction route. Extensive AFM examination revealed NP formation with different attributes (size, distribution depending on electrochemistry conditions. While relatively large NP with >100 nm size and bimodal distribution were obtained after 20 s EC reduction in H3BO3 following Co2+ ion uptake, ultrafine NP (<10 nm could be produced from EC reduction in CoSO4 and H3BO3 mixed solution with some tendency to form oxides. Different carbon nanostructures including few-walled or multiwalled carbon nanotubes (CNT and carbon nanosheets were grown in a C2H2/NH3 plasma using the plasma-enhanced chemical vapor deposition technique. The devised processing routes enable size controlled synthesis of cobalt nanoparticles and metal/carbon hybrid nanostructures with unique microstructural features.

  3. Performance optimum analysis of an irreversible molten carbonate fuel cell–Stirling heat engine hybrid system

    International Nuclear Information System (INIS)

    Chen, Liwei; Zhang, Houcheng; Gao, Songhua; Yan, Huixian

    2014-01-01

    A new hybrid system mainly consists of a molten carbonate fuel cell (MCFC) and a Stirling heat engine is established, where the Stirling heat engine is driven by the high-quality waste heat generated in the MCFC. Based on the electrochemistry and non-equilibrium thermodynamics, analytical expressions for the efficiency and power output of the hybrid system are derived by taking various irreversible losses into account. It shows that the performance of the MCFC can be greatly enhanced by coupling a Stirling heat engine to further convert the waste heat for power generation. By employing numerical calculations, not only the influences of multiple irreversible losses on the performance of the hybrid system are analyzed, but also the impacts of some operating conditions such as the operating temperature, input gas compositions and operating pressure on the performance of the hybrid system are also discussed. The investigation method in the present paper is feasible for some other similar energy conversion systems as well. - Highlights: • A model of MCFC–Stirling heat engine hybrid system is established. • Analytical expressions for the efficiency and power output are derived. • MCFC performance can be greatly enhanced by coupling a Stirling heat engine. • Effects of some operating conditions on the performance are discussed. • Optimum operation regions are subdivided by multi-objective optimization method

  4. Immobilization of carbon nanotubes on functionalized graphene film grown by chemical vapor deposition and characterization of the hybrid material

    Directory of Open Access Journals (Sweden)

    Prashanta Dhoj Adhikari

    2014-01-01

    Full Text Available We report the surface functionalization of graphene films grown by chemical vapor deposition and fabrication of a hybrid material combining multi-walled carbon nanotubes and graphene (CNT–G. Amine-terminated self-assembled monolayers were prepared on graphene by the UV-modification of oxidized groups introduced onto the film surface. Amine-termination led to effective interaction with functionalized CNTs to assemble a CNT–G hybrid through covalent bonding. Characterization clearly showed no defects of the graphene film after the immobilization reaction with CNT. In addition, the hybrid graphene material revealed a distinctive CNT–G structure and p–n type electrical properties. The introduction of functional groups on the graphene film surface and fabrication of CNT–G hybrids with the present technique could provide an efficient, novel route to device fabrication.

  5. A hybrid small-world network/semi-physical model for predicting wildfire spread in heterogeneous landscapes

    International Nuclear Information System (INIS)

    Billaud, Y; Kaiss, A; Drissi, M; Pizzo, Y; Porterie, B; Zekri, N; Acem, Z; Collin, A; Boulet, P; Santoni, P-A; Bosseur, F

    2012-01-01

    This paper presents the latest developments and validation results of a hybrid model which combines a broad-scale stochastic small-world network model with a macroscopic deterministic approach, to simulate the effects of large fires burning in heterogeneous landscapes. In the extended version of the model, vegetation is depicted as an amorphous network of combustible cells, and both radiation and convection from the flaming zone are considered in the preheating process of unburned cells. Examples are given to illustrate small-world effects and fire behavior near the percolation threshold. The model is applied to a Mediterranean fire that occurred in Corsica in 2009 showing a good agreement in terms of rate of spread, and area and shape of the burn. A study, based on a fractional factorial plan, is conducted to evaluate the influence of variations of model parameters on fire propagation.

  6. Multifunctional hybrids for electromagnetic absorption

    International Nuclear Information System (INIS)

    Huynen, I.; Quievy, N.; Bailly, C.; Bollen, P.; Detrembleur, C.; Eggermont, S.; Molenberg, I.; Thomassin, J.M.; Urbanczyk, L.

    2011-01-01

    Highlights: → EM absorption requires low dielectric constant and ∼1 S/m electrical conductivity. → New hybrids were processed with CNT-filled polymer foam inserted in Al honeycomb. → The EM absorption in the GHz range is superior to any known material. → A closed form model is used to guide the design of the hybrid. → The architectured material is light with potential for thermal management. - Abstract: Electromagnetic (EM) interferences are ubiquitous in modern technologies and impact on the reliability of electronic devices and on living cells. Shielding by EM absorption, which is preferable over reflection in certain instances, requires combining a low dielectric constant with high electrical conductivity, which are antagonist properties in the world of materials. A novel class of hybrid materials for EM absorption in the gigahertz range has been developed based on a hierarchical architecture involving a metallic honeycomb filled with a carbon nanotube-reinforced polymer foam. The waveguide characteristics of the honeycomb combined with the performance of the foam lead to unexpectedly large EM power absorption over a wide frequency range, superior to any known material. The peak absorption frequency can be tuned by varying the shape of the honeycomb unit cell. A closed form model of the EM reflection and absorption provides a tool for the optimization of the hybrid. This designed material sets the stage for a new class of sandwich panels combining high EM absorption with mass efficiency, stiffness and thermal management.

  7. Flexible Hybrid Membranes with Ni(OH)2 Nanoplatelets Vertically Grown on Electrospun Carbon Nanofibers for High-Performance Supercapacitors.

    Science.gov (United States)

    Zhang, Longsheng; Ding, Qianwei; Huang, Yunpeng; Gu, Huahao; Miao, Yue-E; Liu, Tianxi

    2015-10-14

    The practical applications of transition metal oxides and hydroxides for supercapacitors are restricted by their intrinsic poor conductivity, large volumetric expansion, and rapid capacitance fading upon cycling, which can be solved by optimizing these materials to nanostructures and confining them within conductive carbonaceous frameworks. In this work, flexible hybrid membranes with ultrathin Ni(OH)2 nanoplatelets vertically and uniformly anchored on the electrospun carbon nanofibers (CNF) have been facilely prepared as electrode materials for supercapacitors. The Ni(OH)2/CNF hybrid membranes with three-dimensional macroporous architectures as well as hierarchical nanostructures can provide open and continuous channels for rapid diffusion of electrolyte to access the electrochemically active Ni(OH)2 nanoplatelets. Moreover, the carbon nanofiber can act both as a conductive core to provide efficient transport of electrons for fast Faradaic redox reactions of the Ni(OH)2 sheath, and as a buffering matrix to mitigate the local volumetric expansion/contraction upon long-term cycling. As a consequence, the optimized Ni(OH)2/CNF hybrid membrane exhibits a high specific capacitance of 2523 F g(-1) (based on the mass of Ni(OH)2, that is 701 F g(-1) based on the total mass) at a scan rate of 5 mV s(-1). The Ni(OH)2/CNF hybrid membranes with high mechanical flexibility, superior electrical conductivity, and remarkably improved electrochemical capacitance are condsidered as promising flexible electrode materials for high-performance supercapacitors.

  8. Leveraging 35 years of Pinus taeda research in the southeastern US to constrain forest carbon cycle predictions: regional data assimilation using ecosystem experiments

    Directory of Open Access Journals (Sweden)

    R. Q. Thomas

    2017-07-01

    Full Text Available Predicting how forest carbon cycling will change in response to climate change and management depends on the collective knowledge from measurements across environmental gradients, ecosystem manipulations of global change factors, and mathematical models. Formally integrating these sources of knowledge through data assimilation, or model–data fusion, allows the use of past observations to constrain model parameters and estimate prediction uncertainty. Data assimilation (DA focused on the regional scale has the opportunity to integrate data from both environmental gradients and experimental studies to constrain model parameters. Here, we introduce a hierarchical Bayesian DA approach (Data Assimilation to Predict Productivity for Ecosystems and Regions, DAPPER that uses observations of carbon stocks, carbon fluxes, water fluxes, and vegetation dynamics from loblolly pine plantation ecosystems across the southeastern US to constrain parameters in a modified version of the Physiological Principles Predicting Growth (3-PG forest growth model. The observations included major experiments that manipulated atmospheric carbon dioxide (CO2 concentration, water, and nutrients, along with nonexperimental surveys that spanned environmental gradients across an 8.6  ×  105 km2 region. We optimized regionally representative posterior distributions for model parameters, which dependably predicted data from plots withheld from the data assimilation. While the mean bias in predictions of nutrient fertilization experiments, irrigation experiments, and CO2 enrichment experiments was low, future work needs to focus modifications to model structures that decrease the bias in predictions of drought experiments. Predictions of how growth responded to elevated CO2 strongly depended on whether ecosystem experiments were assimilated and whether the assimilated field plots in the CO2 study were allowed to have different mortality parameters than the other field

  9. Cooling design and evaluation for photovoltaic cells within constrained space in a CPV/CSP hybrid solar system

    International Nuclear Information System (INIS)

    Wang, Sheng; Shi, Junxiang; Chen, Hsiu-Hung; Schafer, Steven R.; Munir, Moiz; Stecker, Greg; Pan, Wei; Lee, Jong-Jan; Chen, Chung-Lung

    2017-01-01

    Highlights: • A practical cooling solution is proposed for a novel CPV/CSP hybrid solar system. • Both passive and active cooling techniques were systematically investigated. • Comprehensive experimental and numerical studies were conducted for optimal design. • Active cooling is in great need for a high waste heat flux of 21.8 W/cm 2 . • Passive cooling becomes attractive for a waste heat flux less than 13.0 W/cm 2 . - Abstract: A hybrid solar energy system has been designed by combining the advantages of concentrated solar power (CSP) technology and high performance concentrated photovoltaic (CPV) cells which outperforms either single technology. Thermal management is crucial to CPV cells in this hybrid solar system, as concentrated solar radiation onto the PV cells leads to higher heat flux. If the heat is not dissipated effectively, it can cause obvious temperature rise and efficiency reduction in the cell. In addition, the constrained space available for PV cell cooling in such hybrid solar systems presents more challenges. In this study both passive cooling and active cooling techniques were systematically investigated in both numerical and experimental ways. For the passive cooling method, two different designs from off-the-shelf heat pipes with radial fins or annular fins were proposed and studied under various heat rejection requirements. Results shows that heat pipes with radial fins exhibited narrow capability of dumping the heat, while heat pipes with annular fins presented better performances under the same conditions. Numerical optimal designs of annular fin numbers and fin gaps were then carried out and experimentally validated, indicating a capability of dumping moderate waste heat (∼45 W). For active cooling technique, a comprehensive study of designing plate fin heatsinks were conducted corresponding to high Ingress Protection (IP) rated off-the-shelf fans. Results show that with a less than 2 W fan power consumption, this active

  10. Hybrid2 - The hybrid power system simulation model

    Energy Technology Data Exchange (ETDEWEB)

    Baring-Gould, E.I.; Green, H.J.; Dijk, V.A.P. van [National Renewable Energy Lab., Golden, CO (United States); Manwell, J.F. [Univ. of Massachusetts, Amherst, MA (United States)

    1996-12-31

    There is a large-scale need and desire for energy in remote communities, especially in the developing world; however the lack of a user friendly, flexible performance prediction model for hybrid power systems incorporating renewables hindered the analysis of hybrids as options to conventional solutions. A user friendly model was needed with the versatility to simulate the many system locations, widely varying hardware configurations, and differing control options for potential hybrid power systems. To meet these ends, researchers from the National Renewable Energy Laboratory (NREL) and the University of Massachusetts (UMass) developed the Hybrid2 software. This paper provides an overview of the capabilities, features, and functionality of the Hybrid2 code, discusses its validation and future plans. Model availability and technical support provided to Hybrid2 users are also discussed. 12 refs., 3 figs., 4 tabs.

  11. Carbon Dioxide Effects Research and Assessment Program. The role of tropical forests on the world carbon cycle

    Energy Technology Data Exchange (ETDEWEB)

    Brown, S.; Lugo, A. E.; Liegel, B. [eds.

    1980-08-01

    Tropical forests constitute about half of the world's forest and are characterized by rapid rates of organic matter turnover and high storages of organic matter. Tropical forests are considered to be one of the most significant terrestrial elements in the equation that balances the carbon cycle of the world. As discussed in the paper by Tosi, tropical and subtropical latitudes are more complex in terms of climate and vegetation composition than temperate and boreal latitudes. The implications of the complexity of the tropics and the disregard of this complexity by many scientists is made evident in the paper by Brown and Lugo which shows that biomass estimates for tropical ecosystems have been overestimated by at least 100%. The paper by Brown shows that that rates of succession in the tropics are extremely rapid in terms of the ability of moist and wet forests to accumulate organic matter. Yet, in arid tropical Life Zones succession is slow. This leads to the idea that the question of whether tropical forests are sinks or sources of carbon must be analyzed in relation to Life Zones and to intensities of human activity in these Zones. The paper by Lugo presents conceptual models to illustrate this point and the paper by Tosi shows how land uses in the tropics also correspond to Life Zone characteristics. The ultimate significance of land use to the question of the carbon balance in a large region is addressed in the paper by Detwiler and Hall.

  12. The development and mechanical characterization of aluminium copper-carbon fiber metal matrix hybrid composite

    Science.gov (United States)

    Manzoor, M. U.; Feroze, M.; Ahmad, T.; Kamran, M.; Butt, M. T. Z.

    2018-04-01

    Metal matrix composites (MMCs) come under advanced materials that can be used for a wide range of industrial applications. MMCs contain a non-metallic reinforcement incorporated into a metallic matrix which can enhance properties over base metal alloys. Copper-Carbon fiber reinforced aluminium based hybrid composites were prepared by compo casting method. 4 weight % copper was used as alloying element with Al because of its precipitation hardened properties. Different weight compositions of composites were developed and characterized by mechanical testing. A significant improvement in tensile strength and micro hardness were found, before and after heat treatment of the composite. The SEM analysis of the fractured surfaces showed dispersed and embedded Carbon fibers within the network leading to the enhanced strength.

  13. Cellulose nanofibril/reduced graphene oxide/carbon nanotube hybrid aerogels for highly flexible and all-solid-state supercapacitors

    Science.gov (United States)

    Qifeng Zheng; Zhiyong Cai; Zhenqiang Ma; Shaoqin Gong

    2015-01-01

    A novel type of highly flexible and all-solid-state supercapacitor that uses cellulose nanofibril (CNF)/reduced graphene oxide (RGO)/carbon nanotube (CNT) hybrid aerogels as electrodes and H2SO4 poly (vinyl alcohol) PVA gel as the electrolyte was developed and is reported here. These flexible solid-state supercapacitors...

  14. Near infrared optical biosensor based on peptide functionalized single-walled carbon nanotubes hybrids for 2,4,6-trinitrotoluene (TNT) explosive detection.

    Science.gov (United States)

    Wang, Jin

    2018-06-01

    A near infrared (NIR) optical biosensor based on peptide functionalized single-walled carbon nanotubes (SWCNTs) hybrids for 2,4,6-trinitrotoluene (TNT) explosive detection was developed. The TNT binding peptide was directly anchored on the sidewall of the SWCNTs using the π-π interaction between the aromatic amino acids and SWCNTs, forming the peptide-SWCNTs hybrids for near infrared absorption spectra measurement. The evidence of the morphology of peptide-SWCNTs hybrids was obtained using atomic force microscopy (AFM). The results demonstrated that peptide-SWCNTs hybrids based NIR optical biosensor exhibited sensitive and highly selective for TNT explosive determination, addressing a promising optical biosensor for security application. Copyright © 2018. Published by Elsevier Inc.

  15. Social Roots of Global Environmental Change: A World-Systems Analysis of Carbon Dioxide Emissions

    Directory of Open Access Journals (Sweden)

    J. Timmons Roberts

    2015-08-01

    Full Text Available Carbon dioxide is understood to be the most important greenhouse gas believed to be altering the global climate. This article applies world-system theory to environmental damage. An analysis of 154 countries examines the contribution of both position in the world economy and internal class and political forces in determining a nation's CO, intensity. CO, intensity is defined here as the amount of carbon dioxide released per unit of economic output. An inverted U distribution of CO, intensity across the range of countries in the global stratification system is identified and discussed. Ordinary Least Squares regression suggests that the least efficient consumers of fossil fuels are some countries within the semi-periphery and upper periphery, spe-cifically those nations which are high exporters, those highly in debt, nations with higher military spending, and those with a repressive social structure.

  16. Piezoresistive Carbon-based Hybrid Sensor for Body-Mounted Biomedical Applications

    Science.gov (United States)

    Melnykowycz, M.; Tschudin, M.; Clemens, F.

    2017-02-01

    For body-mounted sensor applications, the evolution of soft condensed matter sensor (SCMS) materials offer conformability andit enables mechanical compliance between the body surface and the sensing mechanism. A piezoresistive hybrid sensor and compliant meta-material sub-structure provided a way to engineer sensor physical designs through modification of the mechanical properties of the compliant design. A piezoresistive fiber sensor was produced by combining a thermoplastic elastomer (TPE) matrix with Carbon Black (CB) particles in 1:1 mass ratio. Feedstock was extruded in monofilament fiber form (diameter of 300 microns), resulting in a highly stretchable sensor (strain sensor range up to 100%) with linear resistance signal response. The soft condensed matter sensor was integrated into a hybrid design including a 3D printed metamaterial structure combined with a soft silicone. An auxetic unit cell was chosen (with negative Poisson’s Ratio) in the design in order to combine with the soft silicon, which exhibits a high Poisson’s Ratio. The hybrid sensor design was subjected to mechanical tensile testing up to 50% strain (with gauge factor calculation for sensor performance), and then utilized for strain-based sensing applications on the body including gesture recognition and vital function monitoring including blood pulse-wave and breath monitoring. A 10 gesture Natural User Interface (NUI) test protocol was utilized to show the effectiveness of a single wrist-mounted sensor to identify discrete gestures including finger and hand motions. These hand motions were chosen specifically for Human Computer Interaction (HCI) applications. The blood pulse-wave signal was monitored with the hand at rest, in a wrist-mounted. In addition different breathing patterns were investigated, including normal breathing and coughing, using a belt and chest-mounted configuration.

  17. Gasoline-powered series hybrid cars cause lower life cycle carbon emissions than battery cars

    Science.gov (United States)

    Meinrenken, Christoph; Lackner, Klaus S.

    2012-02-01

    Battery cars powered by grid electricity promise reduced life cycle green house gas (GHG) emissions from the automotive sector. Such scenarios usually point to the much higher emissions from conventional, internal combustion engine cars. However, today's commercially available series hybrid technology achieves the well known efficiency gains in electric drivetrains (regenerative breaking, lack of gearbox) even if the electricity is generated onboard, from conventional fuels. Here, we analyze life cycle GHG emissions for commercially available, state-of the-art plug-in battery cars (e.g. Nissan Leaf) and those of commercially available series hybrid cars (e.g., GM Volt, at same size and performance). Crucially, we find that series hybrid cars driven on (fossil) gasoline cause fewer emissions (126g CO2eq per km) than battery cars driven on current US grid electricity (142g CO2eq per km). We attribute this novel finding to the significant incremental emissions from plug-in battery cars due to losses during grid transmission and battery dis-/charging, and manufacturing larger batteries. We discuss crucial implications for strategic policy decisions towards a low carbon automotive sector as well as relative land intensity when powering cars by biofuel vs. bioelectricity.

  18. Gasoline-powered serial hybrid cars cause lower life cycle carbon emissions than battery cars

    Science.gov (United States)

    Meinrenken, Christoph J.; Lackner, Klaus S.

    2011-04-01

    Battery cars powered by grid electricity promise reduced life cycle green house gas (GHG) emissions from the automotive sector. Such scenarios usually point to the much higher emissions from conventional, internal combustion engine cars. However, today's commercially available serial hybrid technology achieves the well known efficiency gains from regenerative breaking, lack of gearbox, and light weighting - even if the electricity is generated onboard, from conventional fuels. Here, we analyze emissions for commercially available, state-of the-art battery cars (e.g. Nissan Leaf) and those of commercially available serial hybrid cars (e.g., GM Volt, at same size and performance). Crucially, we find that serial hybrid cars driven on (fossil) gasoline cause fewer life cycle GHG emissions (126g CO2e per km) than battery cars driven on current US grid electricity (142g CO2e per km). We attribute this novel finding to the significant incremental life cycle emissions from battery cars from losses during grid transmission, battery dis-/charging, and larger batteries. We discuss crucial implications for strategic policy decisions towards a low carbon automotive sector as well as relative land intensity when powering cars by biofuel vs. bioelectricity.

  19. Stannous sulfide/multi-walled carbon nanotube hybrids as high-performance anode materials of lithium-ion batteries

    International Nuclear Information System (INIS)

    Li, Shuankui; Zuo, Shiyong; Wu, Zhiguo; Liu, Ying; Zhuo, Renfu; Feng, Juanjuan; Yan, De; Wang, Jun; Yan, Pengxun

    2014-01-01

    A hybrid of multi-walled carbon nanotubes (MWCNTs) anchored with SnS nanosheets is synthesized through a simple solvothermal method for the first time. Interestingly, SnS can be controllably deposited onto the MWCNTs backbone in the shape of nanosheets or nanoparticles to form two types of SnS/MWCNTs hybrids, SnS NSs/MWCNTs and SnS NPs/MWCNTs. When evaluated as an anode material for lithium-ion batteries, the hybrids exhibit higher lithium storage capacities and better cycling performance compared to pure SnS. It is found that the SnS NSs/MWCNTs hybrid exhibits a large reversible capacity of 620mAhg −1 at a current of 100mAg −1 as an anode material for lithium-ion batteries, which is better than SnS NPs/MWCNTs. The improved performance may be attributed to the ultrathin nanosheet subunits possess short distance for Li + ions diffusion and large electrode-electrolyte contact area for high Li + ions flux across the interface. It is believed that the structural design of electrodes demonstrated in this work will have important implications on the fabrication of high-performance electrode materials for lithium-ion batteries

  20. The optoelectronic properties of a photosystem I-carbon nanotube hybrid system

    International Nuclear Information System (INIS)

    Kaniber, Simone M; Holleitner, Alexander W; Simmel, Friedrich C; Carmeli, Itai

    2009-01-01

    The photoconductance properties of photosystem I (PSI) covalently bound to carbon nanotubes (CNTs) are measured. We demonstrate that the PSI forms active electronic junctions with the CNTs, enabling control of the CNTs' photoconductance by the PSI. In order to electrically contact the photoactive proteins, a cysteine mutant is generated at one end of the PSI by genetic engineering. The CNTs are covalently bound to this reactive group using carbodiimide chemistry. We detect an enhanced photoconductance signal of the hybrid material at photon wavelengths resonant to the absorption maxima of the PSI compared to non-resonant wavelengths. The measurements prove that it is feasible to integrate photosynthetic proteins into optoelectronic circuits at the nanoscale.

  1. The optoelectronic properties of a photosystem I-carbon nanotube hybrid system

    Energy Technology Data Exchange (ETDEWEB)

    Kaniber, Simone M; Holleitner, Alexander W [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, D-85748 Garching (Germany); Simmel, Friedrich C [LMU Munich, Geschwister-Scholl-Platz 1, D-80539 Muenchen (Germany); Carmeli, Itai, E-mail: holleitner@wsi.tum.d, E-mail: itai@post.tau.ac.i [Chemistry Department and NIBN, Ben Gurion University, 84105 Be' er Sheva (Israel)

    2009-08-26

    The photoconductance properties of photosystem I (PSI) covalently bound to carbon nanotubes (CNTs) are measured. We demonstrate that the PSI forms active electronic junctions with the CNTs, enabling control of the CNTs' photoconductance by the PSI. In order to electrically contact the photoactive proteins, a cysteine mutant is generated at one end of the PSI by genetic engineering. The CNTs are covalently bound to this reactive group using carbodiimide chemistry. We detect an enhanced photoconductance signal of the hybrid material at photon wavelengths resonant to the absorption maxima of the PSI compared to non-resonant wavelengths. The measurements prove that it is feasible to integrate photosynthetic proteins into optoelectronic circuits at the nanoscale.

  2. Canada's power play : the case for a Canadian energy strategy for a carbon-constrained world

    International Nuclear Information System (INIS)

    Gibbins, R.; Roberts, K.

    2008-09-01

    This paper presented the results of a series of energy sector consultations conducted across western Canada to determine expert opinions related to the subject of energy policy in Canada. The consultations indicated that many sector experts and stakeholders feel that climate change must be addressed when designing an energy policy for Canada, and that a fair balance must be obtained between the need for economic and environmental sustainability. The economy should not be compromised by action on climate change, and regional differences should be considered. Results of the study suggested that a Canadian energy strategy should coordinate federal, provincial, territorial, and municipal energy policy initiatives. Energy production targets for a range of renewable and non-renewable energy sources should be established. The strategy should inform and be compatible with a national climate change strategy, and move beyond regulation and singular initiatives such as carbon capture and storage. The strategy should stress energy conservation, send appropriate price signals as financial incentives for change, and recognize the need for public investment in research and technology. The document stated that an effective energy strategy may take many years to establish.

  3. Multiwalled carbon nanotube hybrids as MRI contrast agents

    Directory of Open Access Journals (Sweden)

    Nikodem Kuźnik

    2016-07-01

    Full Text Available Magnetic resonance imaging (MRI is one of the most commonly used tomography techniques in medical diagnosis due to the non-invasive character, the high spatial resolution and the possibility of soft tissue imaging. Contrast agents, such as gadolinium complexes and superparamagnetic iron oxides, are administered to spotlight certain organs and their pathologies. Many new models have been proposed that reduce side effects and required doses of these already clinically approved contrast agents. These new candidates often possess additional functionalities, e.g., the possibility of bioactivation upon action of particular stimuli, thus serving as smart molecular probes, or the coupling with therapeutic agents and therefore combining both a diagnostic and therapeutic role. Nanomaterials have been found to be an excellent scaffold for contrast agents, among which carbon nanotubes offer vast possibilities. The morphology of multiwalled carbon nanotubes (MWCNTs, their magnetic and electronic properties, the possibility of different functionalization and the potential to penetrate cell membranes result in a unique and very attractive candidate for a new MRI contrast agent. In this review we describe the different issues connected with MWCNT hybrids designed for MRI contrast agents, i.e., their synthesis and magnetic and dispersion properties, as well as both in vitro and in vivo behavior, which is important for diagnostic purposes. An introduction to MRI contrast agent theory is elaborated here in order to point to the specific expectations regarding nanomaterials. Finally, we propose a promising, general model of MWCNTs as MRI contrast agent candidates based on the studies presented here and supported by appropriate theories.

  4. 1D Ni-Co oxide and sulfide nanoarray/carbon aerogel hybrid nanostructures for asymmetric supercapacitors with high energy density and excellent cycling stability.

    Science.gov (United States)

    Hao, Pin; Tian, Jian; Sang, Yuanhua; Tuan, Chia-Chi; Cui, Guanwei; Shi, Xifeng; Wong, C P; Tang, Bo; Liu, Hong

    2016-09-15

    The fabrication of supercapacitor electrodes with high energy density and excellent cycling stability is still a great challenge. A carbon aerogel, possessing a hierarchical porous structure, high specific surface area and electrical conductivity, is an ideal backbone to support transition metal oxides and bring hope to prepare electrodes with high energy density and excellent cycling stability. Therefore, NiCo 2 S 4 nanotube array/carbon aerogel and NiCo 2 O 4 nanoneedle array/carbon aerogel hybrid supercapacitor electrode materials were synthesized by assembling Ni-Co precursor needle arrays on the surface of the channel walls of hierarchical porous carbon aerogels derived from chitosan in this study. The 1D nanostructures grow on the channel surface of the carbon aerogel vertically and tightly, contributing to the enhanced electrochemical performance with ultrahigh energy density. The energy density of NiCo 2 S 4 nanotube array/carbon aerogel and NiCo 2 O 4 nanoneedle array/carbon aerogel hybrid asymmetric supercapacitors can reach up to 55.3 Wh kg -1 and 47.5 Wh kg -1 at a power density of 400 W kg -1 , respectively. These asymmetric devices also displayed excellent cycling stability with a capacitance retention of about 96.6% and 92% over 5000 cycles.

  5. Electrochemically Functionalized Seamless Three-Dimensional Graphene-Carbon Nanotube Hybrid for Direct Electron Transfer of Glucose Oxidase and Bioelectrocatalysis.

    Science.gov (United States)

    Terse-Thakoor, Trupti; Komori, Kikuo; Ramnani, Pankaj; Lee, Ilkeun; Mulchandani, Ashok

    2015-12-01

    Three-dimensional seamless chemical vapor deposition (CVD) grown graphene-carbon nanotubes (G-CNT) hybrid film has been studied for its potential in achieving direct electron transfer (DET) of glucose oxidase (GOx) and its bioelectrocatalytic activity in glucose detection. A two-step CVD method was employed for the synthesis of seamless G-CNT hybrid film where CNTs are grown on already grown graphene film on copper foil using iron as a catalyst. Physical characterization using SEM and TEM show uniform dense coverage of multiwall carbon nanotubes (MWCNT) grown directly on graphene with seamless contacts. The G-CNT hybrid film was electrochemically modified to introduce oxygenated functional groups for DET favorable immobilization of GOx. Pristine and electrochemically functionalized G-CNT film was characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry, X-ray photoelectron-spectroscopy, and Raman spectroscopy. The DET between GOx and electrochemically oxidized G-CNT electrode was studied using cyclic voltammetry which showed a pair of well-defined and quasi-reversible redox peaks with a formal potential of -459 mV at pH 7 corresponding to the redox site of GOx. The constructed electrode detected glucose concentration over the clinically relevant range of 2-8 mM with the highest sensitivity of 19.31 μA/mM/cm(2) compared to reported composite hybrid electrodes of graphene oxide and CNTs. Electrochemically functionalized CVD grown seamless G-CNT structure used in this work has potential to be used for development of artificial mediatorless redox enzyme based biosensors and biofuel cells.

  6. A high energy and power sodium-ion hybrid capacitor based on nitrogen-doped hollow carbon nanowires anode

    Science.gov (United States)

    Li, Dongdong; Ye, Chao; Chen, Xinzhi; Wang, Suqing; Wang, Haihui

    2018-04-01

    The sodium ion hybrid capacitor (SHC) has been attracting much attention. However, the SHC's power density is significantly confined to a low level due to the sluggish ion diffusion in the anode. Herein, we propose to use an electrode with a high double layer capacitance as the anode in the SHC instead of insertion anodes. To this aim, nitrogen doped hollow carbon nanowires (N-HCNWs) with a high specific surface area are prepared, and the high capacitive contribution during the sodium ion storage process is confirmed by a series of electrochemical measurements. A new SHC consisting of a N-HCNW anode and a commercial active carbon (AC) cathode is fabricated for the first time. Due to the hybrid charge storage mechanism combining ion insertion and capacitive process, the as-fabricated SHC strikes a balance between the energy density and power density, a energy density of 108 Wh kg-1 and a power density of 9 kW kg-1 can be achieved, which overwhelms the electrochemical performances of most reported AC-based SHCs.

  7. Carbon nanotube-polyamidoamine dendrimer hybrid-modified electrodes for highly sensitive electrochemical detection of microRNA24.

    Science.gov (United States)

    Li, Fengye; Peng, Jing; Zheng, Qiong; Guo, Xiang; Tang, Hao; Yao, Shouzhuo

    2015-01-01

    A simple and ultrasensitive microRNA (miRNA) electrochemical biosensor employing multiwalled carbon nanotube (MWCNT)-polyamidoamine (PAMAM) dendrimer and methylene blue (MB) redox indicator is reported in this work. The assay utilizes a glass carbon (GC) electrode modified with MWCNT-PAMAM, on which the oligonucleotide capture probes are immobilized. The electrochemical detection of miRNAs is completed by measuring the reduction signal change of MB before and after the probe hybridization with target miRNA (miRNA24 is used as a model case). The MWCNT-PAMAM/GC electrode shows greatly enhanced signal to MB reduction in contrast to bare GC electrode. The functionalization of MWCNT with PAMAM maintains the electrochemical property of MWCNT to MB reduction but minimizes the undesired adsorption of MB on the MWCNT surface. The effect of experimental variables on the miRNA detection is investigated and optimized. A detection limit of 0.5 fM and a linear peak current density-concentration relationship up to 100 nM are obtained following 60 min hybridization. The proposed assay is successfully used to detect miRNA24 in total RNA sample extracted from HeLa cells.

  8. Identifying core, exciting, and hybrid attributes in fans' assessments of major (World Cup) spectator sports events.

    Science.gov (United States)

    Gau, Li-Shiue

    2013-12-01

    This paper adopts a methodology of asymmetrical analyses to investigate the relevant importance of spectator sport attributes in terms of their non-linear associations with the benefits that fans experience while watching sports. Questionnaires tapping 16 attributes (e.g., teamwork, sportsmanship, level of competition) and 16 benefits (e.g., good mood, exciting experience, support for my favorite team) were distributed to a sample of fans at the outdoor broadcast of the 2010 World Cup final game at the National Stadium in Kaohsiung, Taiwan. 427 participants rated the importance and benefit of each attribute experienced from watching the game. Attributes were categorized as core, exciting, or hybrid attributes. The star player was the core attribute; rivalry, popularity, and coach were the exciting attributes; and the other 12 attributes were hybrid. Two-dimensional space analyses showed that attributes "sportsmanship, teamwork, and supporting a team" were both explicitly and implicitly important attributes. The methodology of asymmetrical analyses can help managers prioritize the focus of attributes and allocate resources effectively.

  9. Status of Biomass Derived Carbon Materials for Supercapacitor Application

    Directory of Open Access Journals (Sweden)

    Talam Kibona Enock

    2017-01-01

    Full Text Available Environmental concerns and energy security uncertainties associated with fossil fuels have driven the world to shift to renewable energy sources. However, most renewable energy sources with exception of hydropower are intermittent in nature and thus need storage systems. Amongst various storage systems, supercapacitors are the promising candidates for energy storage not only in renewable energies but also in hybrid vehicles and portable devices due to their high power density. Supercapacitor electrodes are almost invariably made of carbon derived from biomass. Several reviews had been focused on general carbon materials for supercapacitor electrode. This review is focused on understanding the extent to which different types of biomasses have been used as porous carbon materials for supercapacitor electrodes. It also details hydrothermal microwave assisted, ionothermal, and molten salts carbonization as techniques of synthesizing activated carbon from biomasses as well as their characteristics and their impacts on electrochemical performance.

  10. Non-aqueous hybrid supercapacitors fabricated with mesoporous TiO2 microspheres and activated carbon electrodes with superior performance

    Science.gov (United States)

    Cai, Yong; Zhao, Bote; Wang, Jie; Shao, Zongping

    2014-05-01

    Mesoporous TiO2 microspheres, synthesized by a facile template-free solvothermal method and subsequent heat treatment, are exploited as the electrode for hybrid supercapacitors. The effects of the calcination temperature on the phase composition, particulate microstructure and morphology are characterized by XRD, Raman, FE-SEM and N2 adsorption/desorption measurements. Hybrid supercapacitors utilizing the as-prepared TiO2 mesoporous microspheres as the negative electrode and activated carbon (AC) as the positive electrode in a non-aqueous electrolyte are fabricated. The electrochemical performance of these hybrid supercapacitors is studied by galvanostatic charge-discharge and cyclic voltammetry (CV). The hybrid supercapacitor built from TiO2 microspheres calcined at 400 °C shows the best performance, delivering an energy density of 79.3 Wh kg-1 at a power density of 178.1 W kg-1. Even at a power density of 9.45 kW kg-1, an energy density of 31.5 Wh kg-1 is reached. These values are much higher than the AC-AC symmetric supercapacitor. In addition, the hybrid supercapacitor exhibits excellent cycling performance, retaining 98% of the initial energy density after 1000 cycles. Such outstanding electrochemical performance of the hybrid supercapacitor is attributed to the matched reaction kinetics between the two electrodes with different energy storage mechanisms.

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

    Directory of Open Access Journals (Sweden)

    Mehran Tehrani

    2014-05-01

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

  12. Structural properties and surface wettability of Cu-containing diamond-like carbon films prepared by a hybrid linear ion beam deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Peng; Sun, Lili; Li, Xiaowei [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Xu, Sheng [Gao Hong Coating Technology Co., Ltd, Huzhou 313000 (China); Ke, Peiling [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang, Aiying, E-mail: aywang@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2015-06-01

    Cu-containing diamond-like carbon (Cu-DLC) films were deposited on Si/glass substrate by a hybrid ion beam deposition system. The Cu concentration (0.1–39.7 at.%) in the film was controlled by varying the sputtering current. The microstructure and composition of Cu-DLC films were investigated systematically. The surface topography, roughness and surface wettability of the films were also studied. Results indicated that with increasing the Cu concentration, the water contact angle of the films changed from 66.8° for pure carbon film to more than 104.4° for Cu-DLC films with Cu concentration larger than 24.4 at.%. In the hydrophilic region, the polar surface energy decreased from 30.54 mJ/m{sup 2} for pure carbon film to 2.48 mJ/m{sup 2} for the film with Cu 7.0 at.%. - Highlights: • Cu-containing diamond-like carbon (DLC) films were deposited by a hybrid ion beam system. • Cu-containing DLC films exhibited a wide range of water contact angle. • The water contact angles vary with the surface energies and surface roughness.

  13. Mesh dependence in PDE-constrained optimisation an application in tidal turbine array layouts

    CERN Document Server

    Schwedes, Tobias; Funke, Simon W; Piggott, Matthew D

    2017-01-01

    This book provides an introduction to PDE-constrained optimisation using finite elements and the adjoint approach. The practical impact of the mathematical insights presented here are demonstrated using the realistic scenario of the optimal placement of marine power turbines, thereby illustrating the real-world relevance of best-practice Hilbert space aware approaches to PDE-constrained optimisation problems. Many optimisation problems that arise in a real-world context are constrained by partial differential equations (PDEs). That is, the system whose configuration is to be optimised follows physical laws given by PDEs. This book describes general Hilbert space formulations of optimisation algorithms, thereby facilitating optimisations whose controls are functions of space. It demonstrates the importance of methods that respect the Hilbert space structure of the problem by analysing the mathematical drawbacks of failing to do so. The approaches considered are illustrated using the optimisation problem arisin...

  14. Carbon nanotubes/magnetite hybrids prepared by a facile synthesis process and their magnetic properties

    International Nuclear Information System (INIS)

    Zhang Li; Ni, Qing-Qing; Natsuki, Toshiaki; Fu Yaqin

    2009-01-01

    In this paper, a facile synthesis process is proposed to prepare multiwalled carbon nanotubes/magnetite (MWCNTs/Fe 3 O 4 ) hybrids. The process involves two steps: (1) water-soluble CNTs are synthesized by one-pot modification using potassium persulfate (KPS) as oxidant. (2) Fe 3 O 4 is assembled along the treated CNTs by employing a facile hydrothermal process with the presence of hydrazine hydrate as the mineralizer. The treated CNTs can be easily dispersed in aqueous solvent. Moreover, X-ray photoelectron spectroscopy (XPS) analysis reveals that several functional groups such as potassium carboxylate (-COOK), carbonyl (-C=O) and hydroxyl (-C-OH) groups are formed on the nanotube surfaces. The MWCNTs/Fe 3 O 4 hybrids are characterized with respect to crystal structure, morphology, element composition and magnetic property by X-ray diffraction (XRD), transmission electron microscopy (TEM), XPS and superconducting quantum interference device (SQUID) magnetometer. XRD and TEM results show that the Fe 3 O 4 nanoparticles with diameter in the range of 20-60 nm were firmly assembled on the nanotube surface. The magnetic property investigation indicated that the CNTs/Fe 3 O 4 hybrids exhibit a ferromagnetic behavior and possess a saturation magnetization of 32.2 emu/g. Further investigation indicates that the size of assembled Fe 3 O 4 nanoparticles can be turned by varying experiment factors. Moreover, a probable growth mechanism for the preparation of CNTs/Fe 3 O 4 hybrids was discussed.

  15. Nuclear-Renewable Hybrid System Economic Basis for Electricity, Fuel, and Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Charles Forsberg; Steven Aumeier

    2014-04-01

    Concerns about climate change and altering the ocean chemistry are likely to limit the use of fossil fuels. That implies a transition to a low-carbon nuclear-renewable electricity grid. Historically variable electricity demand was met using fossil plants with low capital costs, high operating costs, and substantial greenhouse gas emissions. However, the most easily scalable very-low-emissions generating options, nuclear and non-dispatchable renewables (solar and wind), are capital-intensive technologies with low operating costs that should operate at full capacities to minimize costs. No combination of fully-utilized nuclear and renewables can meet the variable electricity demand. This implies large quantities of expensive excess generating capacity much of the time. In a free market this results in near-zero electricity prices at times of high nuclear renewables output and low electricity demand with electricity revenue collapse. Capital deployment efficiency—the economic benefit derived from energy systems capital investment at a societal level—strongly favors high utilization of these capital-intensive systems, especially if low-carbon nuclear renewables are to replace fossil fuels. Hybrid energy systems are one option for better utilization of these systems that consumes excess energy at times of low prices to make some useful product.The economic basis for development of hybrid energy systems is described for a low-carbon nuclear renewable world where much of the time there are massivequantities of excess energy available from the electric sector.Examples include (1) high-temperature electrolysis to generate hydrogen for non-fossil liquid fuels, direct use as a transport fuel, metal reduction, etc. and (2) biorefineries.Nuclear energy with its concentrated constant heat output may become the enabling technology for economically-viable low-carbon electricity grids because hybrid nuclear systems may provide an economic way to produce dispatachable variable

  16. Fabrication of TiO2@Yeast-Carbon Hybrid Composites with the Raspberry-Like Structure and Their Synergistic Adsorption-Photocatalysis Performance

    Directory of Open Access Journals (Sweden)

    Dang Yu

    2013-01-01

    Full Text Available In the present work, we report the preparation and photocatalytic properties of TiO2@yeast-carbon with raspberry-like structure using a pyrolysis method. The products are characterized by field emission scanning electron microscopy (FE-SEM, energy dispersive spectrometry (EDS, X-ray diffraction (XRD, thermal gravimetric and differential thermal analysis (TGA-DTA, Fourier transformed infrared spectroscopy (FT-IR, and ultraviolet visible spectroscopy (UV-VIS, respectively. The results show that the hybrid TiO2@yeast-carbon microspheres have ordered elliptic shapes of uniform size (length = 3.5±0.3 μm; width = 2.5±0.5 μm. UV-VIS ascertains that the as-prepared microspheres possess an obvious light response in a wide range of 250–400 nm. In the decomposition of typical model pollutants including methylene blue and congo red, the hybrid composites exhibited excellent photocatalytic activity for the methylene blue due to the enhanced adsorption ability. Further investigation reveals that the combined effect of adsorption from the yeast-carbon core and photocatalytic degradation from the attached TiO2 nanoparticles were responsible for the improvement of the photocatalytic activities. Hereby, the raspberry-like TiO2@yeast-carbon has promising applications in water purification.

  17. Gas storage carbon with enhanced thermal conductivity

    Science.gov (United States)

    Burchell, Timothy D.; Rogers, Michael Ray; Judkins, Roddie R.

    2000-01-01

    A carbon fiber carbon matrix hybrid adsorbent monolith with enhanced thermal conductivity for storing and releasing gas through adsorption and desorption is disclosed. The heat of adsorption of the gas species being adsorbed is sufficiently large to cause hybrid monolith heating during adsorption and hybrid monolith cooling during desorption which significantly reduces the storage capacity of the hybrid monolith, or efficiency and economics of a gas separation process. The extent of this phenomenon depends, to a large extent, on the thermal conductivity of the adsorbent hybrid monolith. This invention is a hybrid version of a carbon fiber monolith, which offers significant enhancements to thermal conductivity and potential for improved gas separation and storage systems.

  18. Hybridization and genome evolution I: The role of contingency during hybrid speciation

    Directory of Open Access Journals (Sweden)

    Fabrice EROUKHMANOFF, Richard I. BAILEY, Glenn-Peter SæTRE

    2013-10-01

    Full Text Available Homoploid hybrid speciation (HHS involves the recombination of two differentiated genomes into a novel, functional one without a change in chromosome number. Theoretically, there are numerous ways for two parental genomes to recombine. Hence, chance may play a large role in the formation of a hybrid species. If these genome combinations can evolve rapidly following hybridization and sympatric situations are numerous, recurrent homoploid hybrid speciation is a possibility. We argue that three different, but not mutually exclusive, types of contingencies could influence this process. First, many of these “hopeful monsters” of recombinant parent genotypes would likely have low fitness. Only specific combinations of parental genomic contributions may produce viable, intra-fertile hybrid species able to accommodate potential constraints arising from intragenomic conflict. Second, ecological conditions (competition, geography of the contact zones or the initial frequency of both parent species might favor different outcomes ranging from sympatric coexistence to the formation of hybrid swarms and ultimately hybrid speciation. Finally, history may also play an important role in promoting or constraining recurrent HHS if multiple hybridization events occur sequentially and parental divergence or isolation differs along this continuum. We discuss under which conditions HHS may occur multiple times in parallel and to what extent recombination and selection may fuse the parent genomes in the same or different ways. We conclude by examining different approaches that might help to solve this intriguing evolutionary puzzle [Current Zoology 59 (5: 667-674, 2013]. 

  19. Conventional, hybrid, plug-in hybrid or electric vehicles? State-based comparative carbon and energy footprint analysis in the United States

    International Nuclear Information System (INIS)

    Onat, Nuri Cihat; Kucukvar, Murat; Tatari, Omer

    2015-01-01

    Highlights: • Driving patterns and electricity generation mix influence vehicle preferences. • EVs are found to be least carbon-intensive vehicle option in 24 states. • HEVs are found to be the most energy-efficient option in 45 states. • EVs across the board are unfavorable in the marginal electricity mix scenario. • Use of renewable energy to power EVs/PHEVs is crucial. - Abstract: Electric vehicles (EVs), plug-in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs) are often considered as better options in terms of greenhouse gas emissions and energy consumption compared to internal combustion vehicles. However, making any decision among these vehicle options is not a straightforward process due to temporal and spatial variations, such as the sources of the electricity used and regional driving patterns. In this study, we compared these vehicle options across 50 states, taking into account state-specific average and marginal electricity generation mixes, regional driving patterns, and vehicle and battery manufacturing impacts. Furthermore, a policy scenario proposing the widespread use of solar energy to charge EVs and PHEVs is evaluated. Based on the average electricity generation mix scenario, EVs are found to be least carbon-intensive vehicle option in 24 states, while HEVs are found to be the most energy-efficient option in 45 states. In the marginal electricity mix scenario, widespread adoption of EVs is found to be an unwise strategy given the existing and near-future marginal electricity generation mix. On the other hand, EVs can be superior to other alternatives in terms of energy-consumption, if the required energy to generate 1 kW h of electricity is below 1.25 kW h

  20. Sequencing of real-world samples using a microfabricated hybrid device having unconstrained straight separation channels.

    Science.gov (United States)

    Liu, Shaorong; Elkin, Christopher; Kapur, Hitesh

    2003-11-01

    We describe a microfabricated hybrid device that consists of a microfabricated chip containing multiple twin-T injectors attached to an array of capillaries that serve as the separation channels. A new fabrication process was employed to create two differently sized round channels in a chip. Twin-T injectors were formed by the smaller round channels that match the bore of the separation capillaries and separation capillaries were incorporated to the injectors through the larger round channels that match the outer diameter of the capillaries. This allows for a minimum dead volume and provides a robust chip/capillary interface. This hybrid design takes full advantage, such as sample stacking and purification and uniform signal intensity profile, of the unique chip injection scheme for DNA sequencing while employing long straight capillaries for the separations. In essence, the separation channel length is optimized for both speed and resolution since it is unconstrained by chip size. To demonstrate the reliability and practicality of this hybrid device, we sequenced over 1000 real-world samples from Human Chromosome 5 and Ciona intestinalis, prepared at Joint Genome Institute. We achieved average Phred20 read of 675 bases in about 70 min with a success rate of 91%. For the similar type of samples on MegaBACE 1000, the average Phred20 read is about 550-600 bases in 120 min separation time with a success rate of about 80-90%.

  1. Designing photobioreactors based on living cells immobilized in silica gel for carbon dioxide mitigation.

    Science.gov (United States)

    Rooke, Joanna C; Léonard, Alexandre; Meunier, Christophe F; Su, Bao-Lian

    2011-09-19

    Atmospheric carbon dioxide levels have been rising since the industrial revolution, with the most dramatic increase occurring since the end of World War II. Carbon dioxide is widely regarded as one of the major factors contributing to the greenhouse effect, which is of major concern in today's society because it leads to global warming. Photosynthesis is Nature's tool for combating elevated carbon dioxide levels. In essence, photosynthesis allows a cell to harvest solar energy and convert it into chemical energy through the assimilation of carbon dioxide and water. Therefore photosynthesis is regarded as an ideal way to harness the abundance of solar energy that reaches Earth and convert anthropologically generated carbon dioxide into useful carbohydrates, providing a much more sustainable energy source. This Minireview aims to tackle the idea of immobilizing photosynthetic unicellular organisms within inert silica frameworks, providing protection both to the fragile cells and to the external ecosystem, and to use this resultant living hybrid material in a photobioreactor. The viability and activity of various unicellular organisms are summarized alongside design issues of a photobioreactor based on living hybrid materials. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Investigation on Shielding and Mechanical Behavior of Carbon/Stainless Steel Hybrid Yarn Woven Fabrics and Their Composites

    Science.gov (United States)

    Jagatheesan, Krishnasamy; Ramasamy, Alagirusamy; Das, Apurba; Basu, Ananjan

    2017-08-01

    This study investigates the shielding characteristics of carbon/stainless steel/polypropylene (C/SS/PP) hybrid woven fabrics and their composites in low frequency (50 MHz-1.5 GHz) and C band (4-6 GHz) regions. The hybrid yarns prepared from carbon and SS filaments using a direct twisting machine have been made into woven fabric samples using a sample loom. The composite has been made by sandwiching a hybrid yarn fabric between the polypropylene films in a compression molding machine at 180°C for 5 min. The shielding behavior of the fabric and the composites has been tested using a coaxial transmission holder for the low frequency range and a wave guide method for the C band frequency range. It has been observed that a 1 end float composite showed a higher SE of 81.4 dB than the 4 end float (76.2 dB) and the 8 end float composites (64 dB) at the low frequency region. However, at the C band frequency, the effect of fabric structures on shielding effectiveness (SE) of fabric composite depends on thread density. For example, at low thread density, (i.e.) 3.93 ppcm, the 8 end float fabric composite showed the highest SE of 22.7 dB than did the 4 end (20.4 dB) and the 1 end float (16.5 dB) fabric composite. However, at high thread density (6.3 ppcm), the case was the reverse. The 1 end float fabric composite showed the highest SE of 29.7 dB rather than 4 end and 8 end float fabric composites (25.9 dB). In addition, all the composites showed less SE than their fabric forms. The increase in thread density also increased the shielding behavior of composites in both frequency ranges. A nonlinear regression model was developed using the Box-Behnken design for predicting the shielding behavior of fabric composites in C band region. In addition to shielding behavior, mechanical strength of C/SS/PP hybrid yarn, the fabric and composite has been tested using a Zwick Roell tensile tester. It has been observed that the work of rupture of C/SS/PP hybrid yarn is higher (6830.3 g

  3. One-Pot Synthesis of Three-Dimensional Graphene/Carbon Nanotube/SnO2 Hybrid Architectures with Enhanced Lithium Storage Properties.

    Science.gov (United States)

    Zhang, Zheye; Wang, Lu; Xiao, Jian; Xiao, Fei; Wang, Shuai

    2015-08-19

    Three-dimensional (3D) graphene/carbon nanotube (CNT)/SnO2 (GCS) hybrid architectures were constructed by a facile and cost-effective self-assembly method through hydrothermal treatment of a mixture of Sn(2+), CNTs, and graphene oxide (GO). The resultant GCS displayed a 3D hierarchically porous structure with large surface area and excellent electrical conductivity, which could effectively prevent the aggregation and volume variation of SnO2 and accelerate the transport of ions and electrons through 3D pathways. Benefiting from the unique structure and the synergistic effect of different components in the hybrid architectures, the GCS exhibited a remarkably improved reversible capacity of 842 mAh g(-1) after 100 cycles at 0.2 A g(-1) and excellent rate performance for lithium storage compared with that of graphene/SnO2 (GS) hybrid architectures. Hence, the impressive results presented here could provide a universal platform for fabricating graphene/CNT-based hybrid architectures with promising applications in various fields.

  4. Four- and eight-membered rings carbon nanotubes: A new class of carbon nanomaterials

    Science.gov (United States)

    Li, Fangfang; Lu, Junzhe; Zhu, Hengjiang; Lin, Xiang

    2018-06-01

    A new class of carbon nanomaterials composed of alternating four- and eight-membered rings is studied by density functional theory (DFT), including single-walled carbon nanotubes (SWCNTs) double-walled carbon nanotubes (DWCNTs) and triple-walled CNTs (TWCNTs). The analysis of geometrical structure shows that carbon atoms' hybridization in novel carbon tubular clusters (CTCs) and the corresponding carbon nanotubes (CNTs) are both sp2 hybridization; The thermal properties exhibit the high stability of these new CTCs. The results of energy band and density of state (DOS) indicate that the electronic properties of CNTs are independent of their diameter, number of walls and chirality, exhibit obvious metal properties.

  5. Our struggle for climate - a low carbon world with growth is possible

    International Nuclear Information System (INIS)

    Chalendar, Pierre-Andre de

    2015-01-01

    In order to avoid an irreversible climate catastrophe, and as the will and commitments of States are not enough, the mobilisation of companies and enterprises is essential. This book aims to show that enterprises, which have been for long considered as responsible of greenhouse gas emissions, are now at the forefront of the struggle against climate change. The author describes the various challenges faced by French companies regarding climate and the environment. He thinks that the world will always need more energy, more steel, more aluminium, more building materials, more cars, more chemistry, more machines, more tubes and cables. The solution is then a technological one to transform industrial activities for a low carbon or zero carbon and growing economy

  6. Effect of Kevlar and carbon fibres on tensile properties of oil palm/epoxy composites

    Science.gov (United States)

    Amir, S. M. M.; Sultan, M. T. H.; Jawaid, M.; Cardona, F.; Ishak, M. R.; Yusof, M. R.

    2017-12-01

    Hybrid composites with natural and synthetic fibers have captured the interests of many researchers. In this work, Kevlar/oil palm Empty Fruit Bunch (EFB)/Kevlar and carbon/oil palm EFB hybrid/carbon composites were prepared using hand lay-up technique by keeping the oil palm EFB fiber as the core material. The tensile properties which include tensile strength, tensile modulus and elongation at break were investigated. It is observed that the tensile strength and modulus for carbon/oil palm EFB/carbon hybrid composites were much higher as compared with Kevlar/oil palm EFB/Kevlar hybrid composites. However, the elongation at break for Kevlar/oil palm EFB/Kevlar hybrid composites exhibited higher value as compared to carbon/oil palm EFB/carbon hybrid composites and oil palm EFB/epoxy composites. The tensile strength for carbon/oil palm EFB/carbon hybrid composites is 93.6 MPa and the tensile modulus for carbon/oil palm EFB/carbon hybrid composites is 6.5 GPa. The elongation at break for Kevlar/oil palm EFB/Kevlar hybrid composites is 3.6%.

  7. The decadal state of the terrestrial carbon cycle : Global retrievals of terrestrial carbon allocation, pools, and residence times

    NARCIS (Netherlands)

    Bloom, A Anthony; Exbrayat, Jean-François; van der Velde, Ivar R; Feng, Liang; Williams, Mathew

    2016-01-01

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

  8. Silicon spectral response extension through single wall carbon nanotubes in hybrid solar cells

    KAUST Repository

    Del Gobbo, Silvano; Castrucci, P.; Fedele, S.; Riele, L.; Convertino, A.; Morbidoni, M.; De Nicola, F.; Scarselli, M.; Camilli, L.; De Crescenzi, M.

    2013-01-01

    Photovoltaic devices based on single wall carbon nanotubes (SWCNTs) and n-silicon multiple heterojunctions have been fabricated by a SWCNT film transferring process. We report on the ability of the carbon nanotubes to extend the Si spectral range towards the near ultraviolet (UV) and the near infrared regions. Semiconducting and about metallic SWCNT networks have been studied as a function of the film sheet resistance, Rsh. Optical absorbance and Raman spectroscopy have been used to assign nanotube chirality and electronic character. This gave us hints of evidence of the participation of the metal nanotubes in the photocurrent generation. Moreover, we provide evidence that the external quantum efficiency spectral range can be modulated as a function of the SWCNT network sheet resistance in a hybrid SWCNT/Si solar cell. This result will be very useful to further design/optimize devices with improved performance in spectral regions generally not covered by conventional Si p-n devices. © 2013 The Royal Society of Chemistry.

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

    International Nuclear Information System (INIS)

    Gambhir, Ajay; Schulz, Niels; Napp, Tamaryn; Tong, Danlu; Munuera, Luis; Faist, Mark; Riahi, Keywan

    2013-01-01

    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 CO 2 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

  10. Facile preparation of carbon nanotubes-graphene hybrids and the effect of aspect ratio of carbon nanotubes on electrical and thermal properties of silicone rubber based composites

    Science.gov (United States)

    Zhao, Shizhen; Bai, Lu; Zheng, Junping

    2018-01-01

    Thermal exfoliation, as an effective and easily scalable method, was widely used to produce graphene (GE). In order to prevent the severe stacking of GE sheets after thermal exfoliation process, a facile technique was used to solve this problem through the barrier effect of carbon nanotubes (CNTs). Two kinds of CNTs with different aspect ratios (AR) were taken to prepare CNTs-GE hybrids using this technique, and then the effect of AR of CNTs (namely CNTs-L for low AR and CNTs-H for high AR) in the hybrids on the performance of silicone rubber (SR) composites was investigated. The results indicate that the presence of CNTs can effectively impede the stacking of GE sheets and the hybrids are dispersed uniformly in the SR matrix. With the addition of CNTs-GE hybrids, the resulted SR composites exhibit greatly improved electrical and thermal properties, especially for the composites filled with CNTs-H-GE hybrid. At the hybrids content of 3.0 wt%, the volume resistivity of CNTs-H-GE/SR composite is 5 × 104 Ω cm (about 10 orders of magnitude decrease compared with pure SR). And the thermal conductivity increases by 78% compared to the pure SR. But as for the CNTs-L-GE/SR composite, the corresponding values are 3 × 106 Ω cm and 59%, respectively. In terms of thermal stability, the CNTs-H-GE/SR composite containing 1.0 wt% hybrid exhibits the maximum improvement of initial degradation temperature (419 °C) compared with the CNTs-L-GE/SR composite (393 °C) and pure SR (365 °C).

  11. Microenterprise in the First and Third Worlds

    OpenAIRE

    Mark Schreiner

    2001-01-01

    Sparked by examples from the third world, hundreds of microenterprise programmes have been started in the first world. Will they be successful? This paper reviews the evidence and concludes that microenterprise development is more difficult in the first world. For example, the microenterprise sector in the first world is smaller because most people can get wage jobs and because of the public safety net. Unlike third-world entrepreneurs, first-world entrepreneurs are more often constrained by ...

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  13. Hybrid ternary rice paper-manganese oxide-carbon nanotube nanocomposites for flexible supercapacitors

    Science.gov (United States)

    Jiang, Wenchao; Zhang, Kaixi; Wei, Li; Yu, Dingshan; Wei, Jun; Chen, Yuan

    2013-10-01

    Modern portable electronic devices create a strong demand for flexible energy storage devices. Paper based nanocomposites are attractive as sustainable materials for such applications. Here, we directly explored the hydroxyl chemistry of cellulose fibers to synthesize hybrid ternary nanocomposites, comprised of rice paper, single-walled carbon nanotubes (SWCNTs) and manganese oxide nanoparticles. The functional groups on cellulose fibers can react with adsorbed permanganate ions, resulting in uniform deposition of manganese oxide nanoparticles. SWCNTs coated on top of manganese oxide nanoparticles form a highly conductive network connecting individual manganese oxide particles. By using the hybrid ternary composites as electrodes, the assembled two-electrode supercapacitors demonstrated high capacitance (260.2 F g-1), energy (9.0 W h kg-1), power (59.7 kW kg-1), and cycle stability (12% drop after 3000 cycles). In addition, the nanocomposites show good strength and excellent mechanical flexibility, and their capacitance shows negligible changes after bending more than 100 times. These findings suggest that opportunities exist to further explore the rich chemistry of cellulose fibers for innovative energy applications.Modern portable electronic devices create a strong demand for flexible energy storage devices. Paper based nanocomposites are attractive as sustainable materials for such applications. Here, we directly explored the hydroxyl chemistry of cellulose fibers to synthesize hybrid ternary nanocomposites, comprised of rice paper, single-walled carbon nanotubes (SWCNTs) and manganese oxide nanoparticles. The functional groups on cellulose fibers can react with adsorbed permanganate ions, resulting in uniform deposition of manganese oxide nanoparticles. SWCNTs coated on top of manganese oxide nanoparticles form a highly conductive network connecting individual manganese oxide particles. By using the hybrid ternary composites as electrodes, the assembled two

  14. Hybrid polyacrylamide/carbon coating on sulfur cathode for advanced lithium sulfur battery

    International Nuclear Information System (INIS)

    Li, Tao; Yuan, Yan; Hong, Bo; Cao, Huawei; Zhang, Kai; Lai, Yanqing; Liu, Yexiang; Huang, Zixin

    2017-01-01

    Commercialized conductive slurry consisting of polyacrylamide (PAM) and two kinds of carbon black was coated on the surface of sulfur cathode. The hybrid PAM/C coating not only physically blocks but also chemically anchors polysulfides within the cathode, confining their out-diffusion and shuttle. Besides, the flexible and highly-conductive coating layer buffers volume change of the cathode during discharge-charge process and reduces charge transfer resistance. A specific capacity of as high as ∼900 mAh g −1 after 300 cycles is demonstrated for the PAM/C coated cathode, which is a significant improvement of reversible capacity and cycle capability compared to uncoated or conventional PVDF/C coated cathode.

  15. World cheating on the carbon market

    International Nuclear Information System (INIS)

    James, O.

    2010-01-01

    According to several non-governmental organizations, some industrial producers take advantage of a flaw in one of the carbon market mechanisms set up by the Kyoto protocol. These industrialists, mainly from China and India, are involved in the production of HCFC22 refrigerants, and make a substantial profit by artificially generating more greenhouse gases (HFC23) than necessary, then destroying them in order to collect carbon credits which they sell on the carbon market. Explanations about the cheat, details about companies and banks involved in the system, review of past trickeries in carbon quotas, and ways to improve the carbon market are presented

  16. Glucose aided preparation of tungsten sulfide/multi-wall carbon nanotube hybrid and use as counter electrode in dye-sensitized solar cells.

    Science.gov (United States)

    Wu, Jihuai; Yue, Gentian; Xiao, Yaoming; Huang, Miaoliang; Lin, Jianming; Fan, Leqing; Lan, Zhang; Lin, Jeng-Yu

    2012-12-01

    The tungsten sulfide/multi-wall carbon nanotube (WS(2)/MWCNT) hybrid was prepared in the presence of glucose by the hydrothermal route. The hybrid materials were used as counter electrode in the dye-sensitized solar cell (DSSC). The results of cyclic voltammetry measurement and electrochemical impedance spectroscopy indicated that the glucose aided prepared (G-A) WS(2)/MWCNT electrode had low charge-transfer resistance (R(ct)) and high electrocatalytic activity for triiodide reduction. The excellent electrochemical properties for (G-A) WS(2)/MWCNT electrode is due to the synergistic effects of WS(2) and MWCNTs, as well as amorphous carbon introduced by glucose. The DSSC based on the G-A WS(2)/MWCNT counter electrode achieved a high power conversion efficiency of 7.36%, which is comparable with the performance of the DSSC using Pt counter electrode (7.54%).

  17. Mathematical Modeling and a Hybrid NSGA-II Algorithm for Process Planning Problem Considering Machining Cost and Carbon Emission

    Directory of Open Access Journals (Sweden)

    Jin Huang

    2017-09-01

    Full Text Available Process planning is an important function in a manufacturing system; it specifies the manufacturing requirements and details for the shop floor to convert a part from raw material to the finished form. However, considering only economical criterion with technological constraints is not enough in sustainable manufacturing practice; formerly, criteria about low carbon emission awareness have seldom been taken into account in process planning optimization. In this paper, a mathematical model that considers both machining costs reduction as well as carbon emission reduction is established for the process planning problem. However, due to various flexibilities together with complex precedence constraints between operations, the process planning problem is a non-deterministic polynomial-time (NP hard problem. Aiming at the distinctive feature of the multi-objectives process planning optimization, we then developed a hybrid non-dominated sorting genetic algorithm (NSGA-II to tackle this problem. A local search method that considers both the total cost criterion and the carbon emission criterion are introduced into the proposed algorithm to avoid being trapped into local optima. Moreover, the technique for order preference by similarity to an ideal solution (TOPSIS method is also adopted to determine the best solution from the Pareto front. Experiments have been conducted using Kim’s benchmark. Computational results show that process plan schemes with low carbon emission can be captured, and, more importantly, the proposed hybrid NSGA-II algorithm can obtain more promising optimal Pareto front than the plain NSGA-II algorithm. Meanwhile, according to the computational results of Kim’s benchmark, we find that both of the total machining cost and carbon emission are roughly proportional to the number of operations, and a process plan with less operation may be more satisfactory. This study will draw references for the further research on green

  18. Oil turbulence in the next decade. An essay on high oil prices in a supply-constrained world

    International Nuclear Information System (INIS)

    Jesse, J.H.; Van der Linde, C.

    2008-06-01

    A CIEP analysis of the recent development of demand and supply for crude oil indicates that the mismatch in supply and demand growth could cause tighter oil markets than we already experience today. In the World Energy Outlook 2007, the International Energy Agency (IEA) warned of a possible 'energy crunch'. But what was anticipated to happen in the first part of the next decade has been fast-forwarded to today, more than 5 years earlier, and could shake the very foundation of our energy systems if no action is undertaken. Without exaggeration, the recent developments in the international oil market are ground-breaking: a little over a year ago, in January 2007, the West Texas Intermediate crude oil price (WTI) traded for USD50 dollar a barrel. Within a year, the price doubled to USD100 per barrel in January 2008 and pushed through to over USD135 in June 2008, against the backdrop of the fresh market supposition about reaching a whopping USD200 per barrel in 2009. If this proves to be true, the world will not only have moved from an 'Oil Demand-led World' to an 'Oil Supply-constrained World' (since 2004) but, more importantly, will then also experience a radical change in the oil price formation. Until recently, the oil price was largely underpinned by the marginal cost of the last barrel needed to match demand, with some political and economic conjuncture mark-ups or -downs. As will be presented in this paper, the current high oil prices are still primarily driven by structural factors that can be well explained without resorting to blaming speculative investors playing the futures market or the low dollar. But if prices are heading towards USD200 a barrel in 12 months' time, or for that matter even to USD150 a barrel, other drivers will gain prominence over marginal costs as the main driver. In that case, OPEC will have accomplished a long-held wish: oil will then be priced at its real value in the Western world (for instance the economic value of mobility for

  19. Four- and eight-membered rings carbon nanotubes: A new class of carbon nanomaterials

    Directory of Open Access Journals (Sweden)

    Fangfang Li

    2018-06-01

    Full Text Available A new class of carbon nanomaterials composed of alternating four- and eight-membered rings is studied by density functional theory (DFT, including single-walled carbon nanotubes (SWCNTs double-walled carbon nanotubes (DWCNTs and triple-walled CNTs (TWCNTs. The analysis of geometrical structure shows that carbon atoms’ hybridization in novel carbon tubular clusters (CTCs and the corresponding carbon nanotubes (CNTs are both sp2 hybridization; The thermal properties exhibit the high stability of these new CTCs. The results of energy band and density of state (DOS indicate that the electronic properties of CNTs are independent of their diameter, number of walls and chirality, exhibit obvious metal properties. Keywords: Four- and eight-membered rings, Carbon nanotubes, Stability, Electronic properties

  20. In vitro adhesion of staphylococci to diamond-like carbon polymer hybrids under dynamic flow conditions.

    Science.gov (United States)

    Soininen, Antti; Levon, Jaakko; Katsikogianni, Maria; Myllymaa, Katja; Lappalainen, Reijo; Konttinen, Yrjö T; Kinnari, Teemu J; Tiainen, Veli-Matti; Missirlis, Yannis

    2011-03-01

    This study compares the ability of selected materials to inhibit adhesion of two bacterial strains commonly implicated in implant-related infections. These two strains are Staphylococcus aureus (S-15981) and Staphylococcus epidermidis (ATCC 35984). In experiments we tested six different materials, three conventional implant metals: titanium, tantalum and chromium, and three diamond-like carbon (DLC) coatings: DLC, DLC-polydimethylsiloxane hybrid (DLC-PDMS-h) and DLC-polytetrafluoroethylene hybrid (DLC-PTFE-h) coatings. DLC coating represents extremely hard material whereas DLC hybrids represent novel nanocomposite coatings. The two DLC polymer hybrid films were chosen for testing due to their hardness, corrosion resistance and extremely good non-stick (hydrophobic and oleophobic) properties. Bacterial adhesion assay tests were performed under dynamic flow conditions by using parallel plate flow chambers (PPFC). The results show that adhesion of S. aureus to DLC-PTFE-h and to tantalum was significantly (P DLC-PDMS-h (0.671 ± 0.001 × 10(7)/cm(2) and 0.751 ± 0.002 × 10(7)/cm(2) vs. 1.055 ± 0.002 × 10(7)/cm(2), respectively). No significant differences were detected between other tested materials. Hence DLC-PTFE-h coating showed as low susceptibility to S. aureus adhesion as all the tested conventional implant metals. The adherence of S. epidermidis to biomaterials was not significantly (P DLC-PTFE-h films could be used as a biomaterial coating without increasing the risk of implant-related infections.

  1. Sculpting carbon bonds for allotropic transformation through solid-state re-engineering of –sp2 carbon

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyun Young; Araujo, Paulo T.; Kim, Young Lae; Jung, Sung Mi; Jia, Xiaoting; Hong, Sanghyun; Ahn, Chi Won; Kong, Jing; Dresselhaus, Mildred S.; Kar, Swastik; Jung, Yung Joon

    2014-09-15

    Carbon forms one of nature’s strongest chemical bonds; its allotropes having provided some of the most exciting scientific discoveries in recent times. The possibility of inter-allotropic transformations/hybridization of carbon is hence a topic of immense fundamental and technological interest. Such modifications usually require extreme conditions (high temperature, pressure and/or high-energy irradiations), and are usually not well controlled. Here we demonstrate inter-allotropic transformations/hybridizations of specific types that appear uniformly across large-area carbon networks, using moderate alternating voltage pulses. By controlling the pulse magnitude, small-diameter single-walled carbon nanotubes can be transformed predominantly into larger-diameter single-walled carbon nanotubes, multi-walled carbon nanotubes of different morphologies, multi-layered graphene nanoribbons or structures with sp3 bonds. This re-engineering of carbon bonds evolves via a coalescence-induced reconfiguration of sp2 hybridization, terminates with negligible introduction of defects and demonstrates remarkable reproducibility. This reflects a potential step forward for large-scale engineering of nanocarbon allotropes and their junctions.

  2. Harnessing light energy with a planar transparent hybrid of graphene/single wall carbon nanotube/n-type silicon heterojunction solar cell

    DEFF Research Database (Denmark)

    Chen, Leifeng; Yu, Hua; Zhong, Jiasong

    2015-01-01

    The photovoltaic conversion efficiency of a solar cell fabricated by a simple electrophoretic method with a planar transparent hybrid of graphenes (GPs) and single wall carbon nanotubes (SCNTs)/n-type silicon heterojunction was significantly increased compared to GPs/n-Si and SCNTs/n-Si solar cells...

  3. Henkin and Hybrid Logic

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Huertas, Antonia; Manzano, Maria

    2014-01-01

    Leon Henkin was not a modal logician, but there is a branch of modal logic that has been deeply influenced by his work. That branch is hybrid logic, a family of logics that extend orthodox modal logic with special proposition symbols (called nominals) that name worlds. This paper explains why...... Henkin’s techniques are so important in hybrid logic. We do so by proving a completeness result for a hybrid type theory called HTT, probably the strongest hybrid logic that has yet been explored. Our completeness result builds on earlier work with a system called BHTT, or basic hybrid type theory...... is due to the first-order perspective, which lies at the heart of Henin’s best known work and hybrid logic....

  4. Analysis and Modeling for China’s Electricity Demand Forecasting Using a Hybrid Method Based on Multiple Regression and Extreme Learning Machine: A View from Carbon Emission

    Directory of Open Access Journals (Sweden)

    Yi Liang

    2016-11-01

    Full Text Available The power industry is the main battlefield of CO2 emission reduction, which plays an important role in the implementation and development of the low carbon economy. The forecasting of electricity demand can provide a scientific basis for the country to formulate a power industry development strategy and further promote the sustained, healthy and rapid development of the national economy. Under the goal of low-carbon economy, medium and long term electricity demand forecasting will have very important practical significance. In this paper, a new hybrid electricity demand model framework is characterized as follows: firstly, integration of grey relation degree (GRD with induced ordered weighted harmonic averaging operator (IOWHA to propose a new weight determination method of hybrid forecasting model on basis of forecasting accuracy as induced variables is presented; secondly, utilization of the proposed weight determination method to construct the optimal hybrid forecasting model based on extreme learning machine (ELM forecasting model and multiple regression (MR model; thirdly, three scenarios in line with the level of realization of various carbon emission targets and dynamic simulation of effect of low-carbon economy on future electricity demand are discussed. The resulting findings show that, the proposed model outperformed and concentrated some monomial forecasting models, especially in boosting the overall instability dramatically. In addition, the development of a low-carbon economy will increase the demand for electricity, and have an impact on the adjustment of the electricity demand structure.

  5. Political economy constraints on carbon pricing policies: What are the implications for economic efficiency, environmental efficacy, and climate policy design?

    International Nuclear Information System (INIS)

    Jenkins, Jesse D.

    2014-01-01

    Economists traditionally view a Pigouvian fee on carbon dioxide and other greenhouse gas emissions, either via carbon taxes or emissions caps and permit trading (“cap-and-trade”), as the economically optimal or “first-best” policy to address climate change-related externalities. Yet several political economy factors can severely constrain the implementation of these carbon pricing policies, including opposition of industrial sectors with a concentration of assets that would lose considerable value under such policies; the collective action nature of climate mitigation efforts; principal agent failures; and a low willingness-to-pay for climate mitigation by citizens. Real-world implementations of carbon pricing policies can thus fall short of the economically optimal outcomes envisioned in theory. Consistent with the general theory of the second-best, the presence of binding political economy constraints opens a significant “opportunity space” for the design of creative climate policy instruments with superior political feasibility, economic efficiency, and environmental efficacy relative to the constrained implementation of carbon pricing policies. This paper presents theoretical political economy frameworks relevant to climate policy design and provides corroborating evidence from the United States context. It concludes with a series of implications for climate policy making and argues for the creative pursuit of a mix of second-best policy instruments. - Highlights: • Political economy constraints can bind carbon pricing policies. • These constraints can prevent implementation of theoretically optimal carbon prices. • U.S. household willingness-to-pay for climate policy likely falls in the range of $80–$200 per year. • U.S. carbon prices may be politically constrained to as low as $2–$8 per ton of CO 2 . • An opportunity space exists for improvements in climate policy design and outcomes

  6. Mechanism of enhanced performance on a hybrid direct carbon fuel cell using sawdust biofuels

    Science.gov (United States)

    Li, Shuangbin; Jiang, Cairong; Liu, Juan; Tao, Haoliang; Meng, Xie; Connor, Paul; Hui, Jianing; Wang, Shaorong; Ma, Jianjun; Irvine, John T. S.

    2018-04-01

    Biomass is expected to play a significant role in power generation in the near future. With the uprising of carbon fuel cells, hybrid direct carbon fuel cells (HDCFCs) show its intrinsic and incomparable advantages in the generation of clean energy with higher efficiency. In this study, two types of biomass treated by physical sieve and pyrolysis from raw sawdust are investigated on an anode-supported HDCFC. The structure and thermal analysis indicate that raw sawdust has well-formed cellulose I phase with very low ash. Electrochemical performance behaviors for sieved and pyrolyzed sawdust combined with various weight ratios of carbonate are compared in N2 and CO2 purge gas. The results show that the power output of sieved sawdust with 789 mWcm-2 is superior to that of pyrolyzed sawdust in CO2 flowing, as well as in N2 flowing. The anode reaction mechanism for the discrepancy of two fuels is explained and the emphasis is also placed on the modified oxygen-reduction cycle mechanism of catalytic effects of Li2CO3 and K2CO3 salts in promoting cell performance.

  7. The effect of dimensionality of nanostructured carbon on the architecture of organic-inorganic hybrid materials.

    Science.gov (United States)

    Misra, R D K; Depan, D; Shah, J

    2013-08-21

    The natural tendency of carbon nanotubes (CNTs) to agglomerate is an underlying reason that prevents the realization of their full potential. On the other hand, covalent functionalization of CNTs to control dispersion leads to disruption of π-conjugation in CNTs and the non-covalent functionalization leads to a weak CNT-polymer interface. To overcome these challenges, we describe the characteristics of fostering of direct nucleation of polymers on nanostructured carbon (CNTs of diameters (~2-200 nm), carbon nanofibers (~200-300 nm), and graphene), which culminates in interfacial adhesion, resulting from electrostatic and van der Waals interaction in the hybrid nanostructured carbon-polymer architecture. Furthermore, the structure is tunable through a change in undercooling. High density polyethylene and polypropylene were selected as two model polymers and two sets of experiments were carried out. The first set of experiments was carried out using CNTs of diameter ~2-5 nm to explore the effect of undercooling and polymer concentration. The second set of experiments was focused on studying the effect of dimensionality on geometrical confinements. The periodic crystallization of polyethylene on small diameter CNTs is demonstrated to be a consequence of the geometrical confinement effect, rather than epitaxy, such that petal-like disks nucleate on large diameter CNTs, carbon nanofibers, and graphene. The application of the process is illustrated in terms of fabricating a system for cellular uptake and bioimaging.

  8. Carbon-shell-constrained silicon cluster derived from Al-Si alloy as long-cycling life lithium ion batteries anode

    Science.gov (United States)

    Su, Junming; Zhang, Congcong; Chen, Xiang; Liu, Siyang; Huang, Tao; Yu, Aishui

    2018-03-01

    Although silicon is the most promising anode material for Li-ion batteries, large volume expansion during lithiation and delithiation is the main obstacle limiting the commercial application of silicon anodes. There are two ways to alleviate volume expansion and prevent further pulverization of a Si anode: fabrication of a rational nanostructure possessing void spaces and uniform distribution of the conducting sites, without a good balance effect in mitigating the limiting factors and enhancing battery performance. In this paper, we propose a novel nanostructure - a carbon-shell-constrained Si cluster (Si/C shell) with both adequate void space and good distribution of electrical contact sites to guarantee homogeneous lithiation in the initial cycle. Benefiting from the ability to maintain electrical conductivity of the outer carbon shell, even after cluster fragmentation, the Si/C shell synthesized from low-cost commercial Al-Si alloy spheres can deliver 0.03% capacity loss from 100th to 1000th cycles at a current density of 1 A g-1. The Si/C shell sample with the dual functional structure mentioned above can also maintain its own nanostructure during cycling and deliver excellent rate performance. It is a concise and scalable strategy which can simplify the preparation of other alloy anode materials for Li-ion batteries.

  9. Radiation preparation of graphene/carbon nanotubes hybrid fillers for mechanical reinforcement of poly(vinyl alcohol) films

    Science.gov (United States)

    Ma, Hui-Ling; Zhang, Long; Zhang, Youwei; Wang, Shuojue; Sun, Chao; Yu, Hongyan; Zeng, Xinmiao; Zhai, Maolin

    2016-01-01

    Graphene/carbon nanotubes (G/CNTs) hybrid fillers were synthesized by γ-ray radiation reduction of graphene oxide (GO) in presence of CNTs. The obtained hybrid fillers with three-dimensional (3D) interconnected network structure were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). Poly(vinyl alcohol) (PVA) composite films with enhanced mechanical properties and thermal stability were subsequently prepared by solution blending of G/CNTs with PVA matrix. The tensile strength and Young's modulus of PVA composite films containing 1 wt% G/CNTs were measured to be 81.9 MPa and 3.9 GPa respectively, which were 56% and 33.6% higher than those of pure PVA. These substantial improvements could be attributed to the interconnected 3D structure of G/CNTs, homogeneous dispersion as well as the strong hydrogen-bonding interaction between G/CNTs and PVA macromolecular chains.

  10. Multiporous carbon allotropes transformed from symmetry-matched carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Yingxiang Cai

    2016-06-01

    Full Text Available Carbon nanotubes (CNTs with homogeneous diameters have been proven to transform into new carbon allotropes under pressure but no studies on the compression of inhomogeneous CNTs have been reported. In this study, we propose to build new carbon allotropes from the bottom-up by applying pressure on symmetry-matched inhomogeneous CNTs. We find that the (3,0 CNT with point group C3v and the (6,0 CNT with point group C6v form an all sp3 hybridized hexagonal 3060-Carbon crystal, but the (4,0 CNT with point group D4h and the (8,0 CNT with point group D8h polymerize into a sp2+sp3 hybridized tetragonal 4080-Carbon structure. Their thermodynamic, mechanical and dynamic stabilities show that they are potential carbon allotropes to be experimentally synthesized. The multiporous structures, excellently mechanical properties and special electronic structures (semiconductive 3060-Carbon and semimetallic 4080-Carbon imply their many potential applications, such as gases purification, hydrogen storage and lightweight semiconductor devices. In addition, we simulate their feature XRD patterns which are helpful for identifying the two carbon crystals in future experimental studies.

  11. Multiporous carbon allotropes transformed from symmetry-matched carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yingxiang, E-mail: yingxiangcai@ncu.edu.cn; Wang, Hao; Xu, Shengliang; Hu, Yujie; Liu, Ning; Xu, Xuechun [Department of Physics, NanChang University, Jiangxi, Nanchang 330031 (China)

    2016-06-15

    Carbon nanotubes (CNTs) with homogeneous diameters have been proven to transform into new carbon allotropes under pressure but no studies on the compression of inhomogeneous CNTs have been reported. In this study, we propose to build new carbon allotropes from the bottom-up by applying pressure on symmetry-matched inhomogeneous CNTs. We find that the (3,0) CNT with point group C{sub 3v} and the (6,0) CNT with point group C{sub 6v} form an all sp{sup 3} hybridized hexagonal 3060-Carbon crystal, but the (4,0) CNT with point group D{sub 4h} and the (8,0) CNT with point group D{sub 8h} polymerize into a sp{sup 2}+sp{sup 3} hybridized tetragonal 4080-Carbon structure. Their thermodynamic, mechanical and dynamic stabilities show that they are potential carbon allotropes to be experimentally synthesized. The multiporous structures, excellently mechanical properties and special electronic structures (semiconductive 3060-Carbon and semimetallic 4080-Carbon) imply their many potential applications, such as gases purification, hydrogen storage and lightweight semiconductor devices. In addition, we simulate their feature XRD patterns which are helpful for identifying the two carbon crystals in future experimental studies.

  12. Factors that influence m-health implementations in resource constrained areas in the developing world

    CSIR Research Space (South Africa)

    Ouma, S

    2011-11-01

    Full Text Available the primary healthcare levels in order to improve the delivery of services within various communities. They further provide the issues that the mhealth service providers should take into account when providing m-health solutions to the resource constrained...

  13. Carbonate fuel cells: Milliwatts to megawatts

    Science.gov (United States)

    Farooque, M.; Maru, H. C.

    The carbonate fuel cell power plant is an emerging high efficiency, ultra-clean power generator utilizing a variety of gaseous, liquid, and solid carbonaceous fuels for commercial and industrial applications. The primary mover of this generator is a carbonate fuel cell. The fuel cell uses alkali metal carbonate mixtures as electrolyte and operates at ∼650 °C. Corrosion of the cell hardware and stability of the ceramic components have been important design considerations in the early stages of development. The material and electrolyte choices are founded on extensive fundamental research carried out around the world in the 60s and early 70s. The cell components were developed in the late 1970s and early 1980s. The present day carbonate fuel cell construction employs commonly available stainless steels. The electrodes are based on nickel and well-established manufacturing processes. Manufacturing process development, scale-up, stack tests, and pilot system tests dominated throughout the 1990s. Commercial product development efforts began in late 1990s leading to prototype field tests beginning in the current decade leading to commercial customer applications. Cost reduction has been an integral part of the product effort. Cost-competitive product designs have evolved as a result. Approximately half a dozen teams around the world are pursuing carbonate fuel cell product development. The power plant development efforts to date have mainly focused on several hundred kW (submegawatt) to megawatt-class plants. Almost 40 submegawatt units have been operating at customer sites in the US, Europe, and Asia. Several of these units are operating on renewable bio-fuels. A 1 MW unit is operating on the digester gas from a municipal wastewater treatment plant in Seattle, Washington (US). Presently, there are a total of approximately 10 MW capacity carbonate fuel cell power plants installed around the world. Carbonate fuel cell products are also being developed to operate on

  14. Reforming performance of a plasma-catalyst hybrid converter using low carbon fuels

    International Nuclear Information System (INIS)

    Horng, R.-F.; Lai, M.-P.; Huang, H.-H.; Chang, Y.-P.

    2009-01-01

    The reforming performance of a plasma-catalyst hybrid converter using different low carbon fuels was investigated. The methodology was to use arc from spark discharge combined with an appropriate oxygen/carbon molar ratio (O 2 /C) and feeding rate of the supplied mixture. To enhance the mixing and reforming reaction, a gas intake swirl was generated by inducing the mixture tangentially into the reaction chamber. The required energy for fuel processing was provided by heat released through the oxidation of the air-fuel mixture. The reforming temperature as well as the effect of steam addition on the hydrogen production was studied. The results showed that reformate gas temperature had a profound effect on the overall reaction. The H 2 /(CO + CO 2 ) ratio reformed by both methane and propane was shown to increase with temperature and that the optimum ratio was obtained when reforming methane under 650 deg. C. The conversion efficiency of the fuel was also shown to increase with increasing temperature. The best thermal efficiency of 72.01% was obtained near 750 deg. C. The theoretical equilibrium calculations and the experimental results were compared.

  15. The decadal state of the terrestrial carbon cycle

    NARCIS (Netherlands)

    Velde, van der I.R.; Bloom, J.; Exbrayat, J.; Feng, L.; Williams, M.

    2016-01-01

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

  16. How carbon-friendly is nuclear energy? A hybrid MRIO-LCA model of a Spanish facility.

    Science.gov (United States)

    Zafrilla, Jorge E; Cadarso, María-Ángeles; Monsalve, Fabio; de la Rúa, Cristina

    2014-12-16

    Spain faces the challenge of 80-95% greenhouse gas emissions reduction by 2050 (European Energy Roadmap). As a possible first step to fulfill this objective, this paper presents a two-level analysis. First, we estimate the carbon footprint of a hypothetical nuclear facility in Spain. Using a hybrid multiregional input-output model, to avoid truncation while diminishing sector aggregation problems and to improve environmental leakages estimations, we calculate the CO2 equivalent emissions associated with the different phases of the nuclear life-cycle--construction, fuel processing and operation and maintenance--taking into account the countries or regions where the emissions have been generated. Our results estimate a nuclear carbon footprint of 21.30 gCO2e/kWh, of which 89% comes from regions outside Spain. In some regions, the highest impacts are mostly direct (92%, 95%, and 92% of total carbon emissions in the U.S., France, and UK, respectively), meaning that these emissions are linked to the inputs directly required for nuclear energy production; in other regions, indirect emissions are higher (83% in China), which becomes relevant for policy measures. Second, through the analyses of different scenarios, we unravel and quantify how different assumptions that are often taken in the literature result in different carbon emissions.

  17. Sneutrino Hybrid Inflation

    International Nuclear Information System (INIS)

    Antusch, Stefan

    2006-01-01

    We review the scenario of sneutrino hybrid inflation, where one of the singlet sneutrinos, the superpartners of the right-handed neutrinos, plays the role of the inflaton. In a minimal model of sneutrino hybrid inflation, the spectral index is given by ns ≅ 1 + 2γ. With γ = 0.025 ± 0.01 constrained by WMAP, a running spectral index vertical bar dns/dlnk vertical bar << vertical barγvertical bar and a tensor-to-scalar ratio r << γ2 are predicted. Small neutrino masses arise from the seesaw mechanism, with heavy masses for the singlet (s)neutrinos generated by the vacuum expectation value of the waterfall field after inflation. The baryon asymmetry of the universe can be explained by non-thermal leptogenesis via sneutrino inflaton decay, with low reheat temperature TRH ≅ 106 GeV

  18. NiCoBP-doped carbon nanotube hybrid: A novel oxidase mimetic system for highly efficient electrochemical immunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bing; He, Yu; Liu, Bingqian; Tang, Dianping, E-mail: dianping.tang@fzu.edu.cn

    2014-12-03

    Highlights: • We report a new oxidase mimetic system for highly efficient electrochemical immunoassay. • NiCoBP-doped carbon nanotube hybrids were used as the nanocatalysts. • NiCoBP-doped carbon nanotube hybrids were used as the mimic oxidase. - Abstract: NiCoBP-doped multi-walled carbon nanotube (NiCoBP–MWCNT) was first synthesized by using induced electroless-plating method and functionalized with the biomolecules for highly efficient electrochemical immunoassay of prostate-specific antigen (PSA, used as a model analyte). We discovered that the as-synthesized NiCoBP–MWCNT had the ability to catalyze the glucose oxidization with a stable and well-defined redox peak. The catalytic current increased with the increment of the immobilized NiCoBP–MWCNT on the electrode. Transmission electron microscope (TEM) and energy dispersive X-ray spectrometry (EDX) were employed to characterize the as-prepared NiCoBP–MWCNT. Using the NiCoBP–MWCNT-conjugated anti-PSA antibody as the signal-transduction tag, a new enzyme-free electrochemical immunoassay protocol could be designed for the detection of target PSA on the capture antibody-functionalized immunosensing interface. Experimental results revealed that the designed immunoassay system could exhibit good electrochemical responses toward target PSA, and allowed the detection of PSA at a concentration as low as 0.035 ng mL{sup −1}. More importantly, the NiCoBP-MWCNT-based oxidase mimetic system could be further extended for the monitoring of other low-abundance proteins or disease-related biomarkers by tuning the target antibody.

  19. Covalently Bonded Graphene-Carbon Nanotube Hybrid for High-Performance Thermal Interfaces

    DEFF Research Database (Denmark)

    Chen, Jie; Walther, Jens H.; Koumoutsakos, Petros

    2015-01-01

    The remarkable thermal properties of graphene and carbon nanotubes (CNTs) have been the subject of intensive investigations for the thermal management of integrated circuits. However, the small contact area of CNTs and the large anisotropic heat conduction of graphene have hindered...... their applications as effective thermal interface materials (TIMs). Here, a covalently bonded graphene–CNT (G-CNT) hybrid is presented that multiplies the axial heat transfer capability of individual CNTs through their parallel arrangement, while at the same time it provides a large contact area for efficient heat...... extraction. Through computer simulations, it is demonstrated that the G-CNT outperforms few-layer graphene by more than 2 orders of magnitude for the c-axis heat transfer, while its thermal resistance is 3 orders of magnitude lower than the state-of-the-art TIMs. We show that heat can be removed from the G...

  20. Modelling and Vibration Control of Beams with Partially Debonded Active Constrained Layer Damping Patch

    Science.gov (United States)

    SUN, D.; TONG, L.

    2002-05-01

    A detailed model for the beams with partially debonded active constraining damping (ACLD) treatment is presented. In this model, the transverse displacement of the constraining layer is considered to be non-identical to that of the host structure. In the perfect bonding region, the viscoelastic core is modelled to carry both peel and shear stresses, while in the debonding area, it is assumed that no peel and shear stresses be transferred between the host beam and the constraining layer. The adhesive layer between the piezoelectric sensor and the host beam is also considered in this model. In active control, the positive position feedback control is employed to control the first mode of the beam. Based on this model, the incompatibility of the transverse displacements of the active constraining layer and the host beam is investigated. The passive and active damping behaviors of the ACLD patch with different thicknesses, locations and lengths are examined. Moreover, the effects of debonding of the damping layer on both passive and active control are examined via a simulation example. The results show that the incompatibility of the transverse displacements is remarkable in the regions near the ends of the ACLD patch especially for the high order vibration modes. It is found that a thinner damping layer may lead to larger shear strain and consequently results in a larger passive and active damping. In addition to the thickness of the damping layer, its length and location are also key factors to the hybrid control. The numerical results unveil that edge debonding can lead to a reduction of both passive and active damping, and the hybrid damping may be more sensitive to the debonding of the damping layer than the passive damping.

  1. Mechanical and Combustion Performance of Multi-Walled Carbon Nanotubes as an Additive to Paraffin-Based Solid Fuels for Hybrid Rockets

    Science.gov (United States)

    Larson, Daniel B.; Boyer, Eric; Wachs, Trevor; Kuo, Kenneth, K.; Koo, Joseph H.; Story, George

    2012-01-01

    Paraffin-based solid fuels for hybrid rocket motor applications are recognized as a fastburning alternative to other fuel binders such as HTPB, but efforts to further improve the burning rate and mechanical properties of paraffin are still necessary. One approach that is considered in this study is to use multi-walled carbon nanotubes (MWNT) as an additive to paraffin wax. Carbon nanotubes provide increased electrical and thermal conductivity to the solid-fuel grains to which they are added, which can improve the mass burning rate. Furthermore, the addition of ultra-fine aluminum particles to the paraffin/MWNT fuel grains can enhance regression rate of the solid fuel and the density impulse of the hybrid rocket. The multi-walled carbon nanotubes also present the possibility of greatly improving the mechanical properties (e.g., tensile strength) of the paraffin-based solid-fuel grains. For casting these solid-fuel grains, various percentages of MWNT and aluminum particles will be added to the paraffin wax. Previous work has been published about the dispersion and mixing of carbon nanotubes.1 Another manufacturing method has been used for mixing the MWNT with a phenolic resin for ablative applications, and the manufacturing and mixing processes are well-documented in the literature.2 The cost of MWNT is a small fraction of single-walled nanotubes. This is a scale-up advantage as future applications and projects will require low cost additives to maintain cost effectiveness. Testing of the solid-fuel grains will be conducted in several steps. Dog bone samples will be cast and prepared for tensile testing. The fuel samples will also be analyzed using thermogravimetric analysis and a high-resolution scanning electron microscope (SEM). The SEM will allow for examination of the solid fuel grain for uniformity and consistency. The paraffin-based fuel grains will also be tested using two hybrid rocket test motors located at the Pennsylvania State University s High Pressure

  2. Experiences Using Hybrid MPI/OpenMP in the Real World: Parallelization of a 3D CFD Solver for Multi-Core Node Clusters

    Directory of Open Access Journals (Sweden)

    Gabriele Jost

    2010-01-01

    Full Text Available Today most systems in high-performance computing (HPC feature a hierarchical hardware design: shared-memory nodes with several multi-core CPUs are connected via a network infrastructure. When parallelizing an application for these architectures it seems natural to employ a hierarchical programming model such as combining MPI and OpenMP. Nevertheless, there is the general lore that pure MPI outperforms the hybrid MPI/OpenMP approach. In this paper, we describe the hybrid MPI/OpenMP parallelization of IR3D (Incompressible Realistic 3-D code, a full-scale real-world application, which simulates the environmental effects on the evolution of vortices trailing behind control surfaces of underwater vehicles. We discuss performance, scalability and limitations of the pure MPI version of the code on a variety of hardware platforms and show how the hybrid approach can help to overcome certain limitations.

  3. Carbonation of Subduction Interface Ultramafic Rocks and Implications for Deep Carbon Cycling: Evidence from Hybrid Serpentinite-Marble in the Voltri Massif, Italy

    Science.gov (United States)

    Scambelluri, M.; Bebout, G. E.; Gilio, M.; Belmonte, D.; Campomenosi, N.; Crispini, L.

    2015-12-01

    Release of COH fluids from hydrous minerals and carbonates influences element recycling and magmatism at subduction zones. Contradictory interpretations exist regarding the retention/storage of C in subducting plates and in the forearc to subarc mantle. Multiple lines of evidence indicate mobility of C in forearcs; however, the magnitude of this loss is highly uncertain[1-5]. A poorly constrained fraction of the 40-115 Mt/y of C initially subducted is released into fluids (e.g., by decarbonation, carbonate dissolution), and 18-43 Mt/y is returned at arc volcanoes[2-5, refs. therein]. The imbalance could reflect subduction into the deeper mantle or forearc/subarc storage[4-7]. We examine the fate of C in slab/interface ultramafic rocks, and by analogy serpentinized mantle wedge, via study of fluid-rock evolution of marble and variably carbonated serpentinite (Ligurian Alps). Based on petrography, and major/trace element and C and O isotope compositions, we demonstrate that serpentinite dehydration at 2-2.5 GPa, 550°C released aqueous fluids triggering breakdown of dolomite in nearby marbles, thus releasing C into fluids. Carbonate + olivine veins document flow of COH fluids; interaction of these COH fluids with serpentinite led to formation of high-pressure carbonated ultramafic-rock domains, thus resulting in retention of C in some rocks at an ancient subduction interface. We stress that lithologically complex interfaces could contain sites of both C release and C addition, further confounding estimates of net C loss at forearc and subarc depths [cf 4,5]. Sites of C retention, also including carbonate veins and graphite as reduced carbonate[7], could influence the transfer of slab C to at least the depths beneath volcanic fronts. 1. Poli S et al. 2009 EPSL; 2. Ague and Nicolescu 2014 Nat Geosci; 3. Cook-Collars et al. 2014 Chem Geol; 4. Collins et al. 2015 Chem Geol; 5. Kelemen and Manning 2015 PNAS; 6. Sapienza et al. 2009 CMP; 7 Galvez et al. 2013 Nat Geosci

  4. Selection of magnetorheological brake types via optimal design considering maximum torque and constrained volume

    International Nuclear Information System (INIS)

    Nguyen, Q H; Choi, S B

    2012-01-01

    This research focuses on optimal design of different types of magnetorheological brakes (MRBs), from which an optimal selection of MRB types is identified. In the optimization, common types of MRB such as disc-type, drum-type, hybrid-types, and T-shaped type are considered. The optimization problem is to find the optimal value of significant geometric dimensions of the MRB that can produce a maximum braking torque. The MRB is constrained in a cylindrical volume of a specific radius and length. After a brief description of the configuration of MRB types, the braking torques of the MRBs are derived based on the Herschel–Bulkley model of the MR fluid. The optimal design of MRBs constrained in a specific cylindrical volume is then analysed. The objective of the optimization is to maximize the braking torque while the torque ratio (the ratio of maximum braking torque and the zero-field friction torque) is constrained to be greater than a certain value. A finite element analysis integrated with an optimization tool is employed to obtain optimal solutions of the MRBs. Optimal solutions of MRBs constrained in different volumes are obtained based on the proposed optimization procedure. From the results, discussions on the optimal selection of MRB types depending on constrained volumes are given. (paper)

  5. Long-term pattern and magnitude of soil carbon feedback to the climate system in a warming world.

    Science.gov (United States)

    Melillo, J M; Frey, S D; DeAngelis, K M; Werner, W J; Bernard, M J; Bowles, F P; Pold, G; Knorr, M A; Grandy, A S

    2017-10-06

    In a 26-year soil warming experiment in a mid-latitude hardwood forest, we documented changes in soil carbon cycling to investigate the potential consequences for the climate system. We found that soil warming results in a four-phase pattern of soil organic matter decay and carbon dioxide fluxes to the atmosphere, with phases of substantial soil carbon loss alternating with phases of no detectable loss. Several factors combine to affect the timing, magnitude, and thermal acclimation of soil carbon loss. These include depletion of microbially accessible carbon pools, reductions in microbial biomass, a shift in microbial carbon use efficiency, and changes in microbial community composition. Our results support projections of a long-term, self-reinforcing carbon feedback from mid-latitude forests to the climate system as the world warms. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  6. SU-F-T-134: Can We Use the Same Dose Constrains Learnt From Photon World to Plan Proton for Lung Cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Z [Rutgers Cancer Institute of New Jersey, New Brunswick, NJ (United States); Zou, J; Yue, N [Rutgers University, New Brunswick, NJ (United States); Zhang, M [Rutgers Cancer Institute of New Jersey, Rutgers The State University of New, New Brunswick, NJ (United States)

    2016-06-15

    Purpose: To evaluate if the same DVH constrains used in photon plans can be safely used to plan proton therapy for lung cancer. Since protons and photons have different dose deposition patterns, the hypothesis is following DVH constrains derived from photon world is not safe for proton. Methods: We retrospectively evaluated plans for 11 lung cancer patients. Each patient was planned with photon and proton following the same dose constrains. Dose statistics on PTV, normal lung, heart and esophagus were extracted for comparison. gEUD for normal lung was calculated and compared between proton and photon plans. We calculated series of gEUDs for each plan by varying the parameter “a” in gEUD formula from 0.1 to 3, covering the whole confidence interval. Results: For all patients, proton plans yield similar PTV coverage and lower dose to heart and esophagus than photon plans. Normal lung V5 was 32.3 % on average in proton plans than 55.4 % in photon. Normal lung gEUD monotonically increased with increasing “a” for all proton and photon plans. For a given patient, the gEUD-proton(a) had a steeper slope than gEUD-photon(a). The two curves crossed for 8 out of 11 patients when “a” = [0.1, 3]. a-crossing ranged from 0.8 to 2.44 with an average of 1.15. For a

  7. SU-F-T-134: Can We Use the Same Dose Constrains Learnt From Photon World to Plan Proton for Lung Cancer?

    International Nuclear Information System (INIS)

    Xiao, Z; Zou, J; Yue, N; Zhang, M

    2016-01-01

    Purpose: To evaluate if the same DVH constrains used in photon plans can be safely used to plan proton therapy for lung cancer. Since protons and photons have different dose deposition patterns, the hypothesis is following DVH constrains derived from photon world is not safe for proton. Methods: We retrospectively evaluated plans for 11 lung cancer patients. Each patient was planned with photon and proton following the same dose constrains. Dose statistics on PTV, normal lung, heart and esophagus were extracted for comparison. gEUD for normal lung was calculated and compared between proton and photon plans. We calculated series of gEUDs for each plan by varying the parameter “a” in gEUD formula from 0.1 to 3, covering the whole confidence interval. Results: For all patients, proton plans yield similar PTV coverage and lower dose to heart and esophagus than photon plans. Normal lung V5 was 32.3 % on average in proton plans than 55.4 % in photon. Normal lung gEUD monotonically increased with increasing “a” for all proton and photon plans. For a given patient, the gEUD-proton(a) had a steeper slope than gEUD-photon(a). The two curves crossed for 8 out of 11 patients when “a” = [0.1, 3]. a-crossing ranged from 0.8 to 2.44 with an average of 1.15. For a< a-crossing, gEUD-proton was less than gEUD-photon and vice versa. Conclusion: The current clinical guideline is the lower normal lung V5 would associated with less complications. However, proton plans with a lower normal lung V5 could yield a higher gEUD than photon if the real “a” is larger than a-crossing. Since a-crossing was within the possible range of real “a”, simply following the normal lung V5 guideline for proton plan would not be a good practice. More comprehensive methods should be developed to evaluate the proton plan.

  8. Hybrid calcium carbonate/polymer microparticles containing silver nanoparticles as antibacterial agents

    Science.gov (United States)

    Długosz, Maciej; Bulwan, Maria; Kania, Gabriela; Nowakowska, Maria; Zapotoczny, Szczepan

    2012-12-01

    We report here on synthesis and characterization of novel hybrid material consisting of silver nanoparticles (nAgs) embedded in calcium carbonate microparticles (μ-CaCO3) serving as carriers for sustained release. nAgs are commonly used as antimicrobial agents in many commercial products (textiles, cosmetics, and drugs). Although they are considered to be safe, their interactions with human organisms are still not fully understood; therefore it is important to apply them with caution and limit their presence in the environment. The synthesis of the new material was based on the co-precipitation of CaCO3 and nAg in the presence of poly(sodium 4-styrenesulfonate). Such designed system enables sustained release of nAg to the environment. This hybrid colloidal material (nAg/μ-CaCO3) was characterized by microscopic and spectroscopic methods. The release of nAg from μ-CaCO3 microparticles was followed in water at various pH values. Microbiological tests confirmed the effectiveness of these microparticles as an antibacterial agent. Importantly, the material can be stored as a dry powder and subsequently re-suspended in water without the risk of losing its antimicrobial activity. nAg/μ-CaCO3 was applied here to insure bacteriostatic properties of down feathers that may significantly prolong their lifetime in typical applications. Such microparticles may be also used as, e.g., components of coatings and paints protecting various surfaces against microorganism colonization.

  9. Hybrid calcium carbonate/polymer microparticles containing silver nanoparticles as antibacterial agents

    Energy Technology Data Exchange (ETDEWEB)

    Dlugosz, Maciej; Bulwan, Maria; Kania, Gabriela; Nowakowska, Maria; Zapotoczny, Szczepan, E-mail: zapotocz@chemia.uj.edu.pl [Jagiellonian University, Faculty of Chemistry (Poland)

    2012-12-15

    We report here on synthesis and characterization of novel hybrid material consisting of silver nanoparticles (nAgs) embedded in calcium carbonate microparticles ({mu}-CaCO{sub 3}) serving as carriers for sustained release. nAgs are commonly used as antimicrobial agents in many commercial products (textiles, cosmetics, and drugs). Although they are considered to be safe, their interactions with human organisms are still not fully understood; therefore it is important to apply them with caution and limit their presence in the environment. The synthesis of the new material was based on the co-precipitation of CaCO{sub 3} and nAg in the presence of poly(sodium 4-styrenesulfonate). Such designed system enables sustained release of nAg to the environment. This hybrid colloidal material (nAg/{mu}-CaCO{sub 3}) was characterized by microscopic and spectroscopic methods. The release of nAg from {mu}-CaCO{sub 3} microparticles was followed in water at various pH values. Microbiological tests confirmed the effectiveness of these microparticles as an antibacterial agent. Importantly, the material can be stored as a dry powder and subsequently re-suspended in water without the risk of losing its antimicrobial activity. nAg/{mu}-CaCO{sub 3} was applied here to insure bacteriostatic properties of down feathers that may significantly prolong their lifetime in typical applications. Such microparticles may be also used as, e.g., components of coatings and paints protecting various surfaces against microorganism colonization.

  10. Hybrid calcium carbonate/polymer microparticles containing silver nanoparticles as antibacterial agents

    International Nuclear Information System (INIS)

    Długosz, Maciej; Bulwan, Maria; Kania, Gabriela; Nowakowska, Maria; Zapotoczny, Szczepan

    2012-01-01

    We report here on synthesis and characterization of novel hybrid material consisting of silver nanoparticles (nAgs) embedded in calcium carbonate microparticles (μ-CaCO 3 ) serving as carriers for sustained release. nAgs are commonly used as antimicrobial agents in many commercial products (textiles, cosmetics, and drugs). Although they are considered to be safe, their interactions with human organisms are still not fully understood; therefore it is important to apply them with caution and limit their presence in the environment. The synthesis of the new material was based on the co-precipitation of CaCO 3 and nAg in the presence of poly(sodium 4-styrenesulfonate). Such designed system enables sustained release of nAg to the environment. This hybrid colloidal material (nAg/μ-CaCO 3 ) was characterized by microscopic and spectroscopic methods. The release of nAg from μ-CaCO 3 microparticles was followed in water at various pH values. Microbiological tests confirmed the effectiveness of these microparticles as an antibacterial agent. Importantly, the material can be stored as a dry powder and subsequently re-suspended in water without the risk of losing its antimicrobial activity. nAg/μ-CaCO 3 was applied here to insure bacteriostatic properties of down feathers that may significantly prolong their lifetime in typical applications. Such microparticles may be also used as, e.g., components of coatings and paints protecting various surfaces against microorganism colonization.

  11. Flexible and freestanding supercapacitor based on nanostructured poly(m-aminophenol)/carbon nanofiber hybrid mats with high energy and power densities

    Science.gov (United States)

    Choudhury, Arup; Dey, Baban; Sinha Mahapatra, Susanta; Kim, Doo-Won; Yang, Kap-Seung; Yang, Duck-Joo

    2018-04-01

    Nanostructured poly(m-aminophenol) (PmAP) coated freestanding carbon nanofiber (CNF) mats were fabricated through simple in situ rapid-mixing polymerization of m-aminophenol in the presence of a CNF mat for flexible solid-state supercapacitors. The surface compositions, morphology and pore structure of the hybrid mats were characterized by using various techniques, e.g., FTIR, Raman, XRD, FE-SEM, TEM, and N2 absorption. The results show that the PmAP nanoparticles were homogeneously deposited on CNF surfaces and formed a thin flexible hybrid mat, which were directly used to made electrodes for electrochemical analysis without using any binders or conductive additives. The electrochemical performances of the hybrid mats were easily tailored by varying the PmAP loading on a hybrid electrode. The PmAP/CNF-10 hybrid electrode with a relatively low PmAP loading (> 42 wt%) showed a high specific capacitance of 325.8 F g-1 and a volumetric capacitance of 273.6 F cm-3 at a current density of 0.5 A g-1, together with a specific capacitance retention of 196.2 F g-1 at 20 A g-1. The PmAP/CNF-10 hybrid electrode showed good cycling stability with 88.2% capacitance retention after 5000 cycles. A maximum energy density of 45.2 Wh kg-1 and power density of 20.4 kW kg-1 were achieved for the PmAP/CNF-10 hybrid electrode. This facile and cost-effective synthesis of a flexible binder-free PmAP/CNF hybrid mat with excellent capacitive performances encourages its possible commercial exploitation.

  12. Shape anisotropy and hybridization enhanced magnetization in nanowires of Fe/MgO/Fe encapsulated in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Aryee, Dennis [Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD 21005 (United States); Department of Physics and Engineering Physics, Morgan State University, Baltimore, MD 21251 (United States); Seifu, Dereje, E-mail: dereje.seifu@morgan.edu [Department of Physics and Engineering Physics, Morgan State University, Baltimore, MD 21251 (United States)

    2017-05-01

    Arrays of tunneling magnetoresistance (TMR) nanowires were synthesized for the first time by filling Fe/MgO/Fe inside vertically grown and substrate supported carbon nanotubes. The magnetic properties of nanowires and planar nanoscale thin films of Fe/MgO/Fe showed several similarities, such as two-fold magnetic symmetry and ratio of orbital moment to spin moment. Nanowires of Fe/MgO/Fe showed higher saturation magnetization by a factor of 2.7 compared to planar thin films of Fe/MgO/Fe at 1.5 kOe. The enhanced magnetic properties likely resulted from shape anisotropy of the nanowires and as well as the hybridization that occur between the π- electronic states of carbon and 3d-bands of the Fe-surface.

  13. The behavior after intravenous injection in mice of multiwalled carbon nanotube / Fe3O4 hybrid MRI contrast agents.

    Science.gov (United States)

    Wu, Huixia; Liu, Gang; Zhuang, Yeming; Wu, Dongmei; Zhang, Haoqiang; Yang, Hong; Hu, He; Yang, Shiping

    2011-07-01

    Fe(3)O(4) nanoparticles were in situ loaded on the surface of multiwalled carbon nanotubes (MWCNTs) by a solvothermal method using diethylene glycol and diethanolamine as solvents and complexing agents. The as-prepared MWCNT/Fe(3)O(4) hybrids exhibited excellent hydrophilicity, superparamagnetic property at room temperature, and a high T(2) relaxivity of 175.5 mM(-1) s(-1) in aqueous solutions. In vitro experiments revealed that MWCNT/Fe(3)O(4) had an excellent magnetic resonance imaging (MRI) enhancement effect on cancer cells, and importantly, they displayed low cytotoxicity and neglectable hemolytic activity. After intravenous administration, the T(2)-weighted MRI signal in the liver and spleen of mice decreased significantly, suggesting the potential application of the hybrids as MRI contrast agents. The organ biodistribution studies, histological analyses and elimination investigations showed that the hybrids were uptaken by the liver, lung and spleen after intravenous injection, and could be excreted from the liver and kidney. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. 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...

  15. Preparation and characterization of flexible asymmetric supercapacitors based on transition-metal-oxide nanowire/single-walled carbon nanotube hybrid thin-film electrodes.

    Science.gov (United States)

    Chen, Po-Chiang; Shen, Guozhen; Shi, Yi; Chen, Haitian; Zhou, Chongwu

    2010-08-24

    In the work described in this paper, we have successfully fabricated flexible asymmetric supercapacitors (ASCs) based on transition-metal-oxide nanowire/single-walled carbon nanotube (SWNT) hybrid thin-film electrodes. These hybrid nanostructured films, with advantages of mechanical flexibility, uniform layered structures, and mesoporous surface morphology, were produced by using a filtration method. Here, manganese dioxide nanowire/SWNT hybrid films worked as the positive electrode, and indium oxide nanowire/SWNT hybrid films served as the negative electrode in a designed ASC. In our design, charges can be stored not only via electrochemical double-layer capacitance from SWNT films but also through a reversible faradic process from transition-metal-oxide nanowires. In addition, to obtain stable electrochemical behavior during charging/discharging cycles in a 2 V potential window, the mass balance between two electrodes has been optimized. Our optimized hybrid nanostructured ASCs exhibited a superior device performance with specific capacitance of 184 F/g, energy density of 25.5 Wh/kg, and columbic efficiency of approximately 90%. In addition, our ASCs exhibited a power density of 50.3 kW/kg, which is 10-fold higher than obtained in early reported ASC work. The high-performance hybrid nanostructured ASCs can find applications in conformal electrics, portable electronics, and electrical vehicles.

  16. Carbon dioxide Information Analysis Center and World Data Center: A for Atmospheric trace gases. Annual progress report, FY 1994

    Energy Technology Data Exchange (ETDEWEB)

    Burtis, M.D. [comp.] [Tennessee Univ., Knoxville, TN (United States). Energy, Environment and Resources Center; Cushman, R.M.; Boden, T.A.; Jones, S.B.; Nelson, T.R.; Stoss, F.W. [Oak Ridge National Lab., TN (United States)

    1995-03-01

    This report summarizes the activities and accomplishments made by the Carbon Dioxide Information Analysis Center and World Data Center-A for Atmospheric Trace Gases during the fiscal year 1994. Topics discussed in this report include; organization and staff, user services, systems, communications, Collaborative efforts with China, networking, ocean data and activities of the World Data Center-A.

  17. Oxygen- and Lithium-Doped Hybrid Boron-Nitride/Carbon Networks for Hydrogen Storage.

    Science.gov (United States)

    Shayeganfar, Farzaneh; Shahsavari, Rouzbeh

    2016-12-20

    Hydrogen storage capacities have been studied on newly designed three-dimensional pillared boron nitride (PBN) and pillared graphene boron nitride (PGBN). We propose these novel materials based on the covalent connection of BNNTs and graphene sheets, which enhance the surface and free volume for storage within the nanomaterial and increase the gravimetric and volumetric hydrogen uptake capacities. Density functional theory and molecular dynamics simulations show that these lithium- and oxygen-doped pillared structures have improved gravimetric and volumetric hydrogen capacities at room temperature, with values on the order of 9.1-11.6 wt % and 40-60 g/L. Our findings demonstrate that the gravimetric uptake of oxygen- and lithium-doped PBN and PGBN has significantly enhanced the hydrogen sorption and desorption. Calculations for O-doped PGBN yield gravimetric hydrogen uptake capacities greater than 11.6 wt % at room temperature. This increased value is attributed to the pillared morphology, which improves the mechanical properties and increases porosity, as well as the high binding energy between oxygen and GBN. Our results suggest that hybrid carbon/BNNT nanostructures are an excellent candidate for hydrogen storage, owing to the combination of the electron mobility of graphene and the polarized nature of BN at heterojunctions, which enhances the uptake capacity, providing ample opportunities to further tune this hybrid material for efficient hydrogen storage.

  18. Climate-Driven Reshuffling of Species and Genes: Potential Conservation Roles for Species Translocations and Recombinant Hybrid Genotypes.

    Science.gov (United States)

    Scriber, Jon Mark

    2013-12-24

    Comprising 50%-75% of the world's fauna, insects are a prominent part of biodiversity in communities and ecosystems globally. Biodiversity across all levels of biological classifications is fundamentally based on genetic diversity. However, the integration of genomics and phylogenetics into conservation management may not be as rapid as climate change. The genetics of hybrid introgression as a source of novel variation for ecological divergence and evolutionary speciation (and resilience) may generate adaptive potential and diversity fast enough to respond to locally-altered environmental conditions. Major plant and herbivore hybrid zones with associated communities deserve conservation consideration. This review addresses functional genetics across multi-trophic-level interactions including "invasive species" in various ecosystems as they may become disrupted in different ways by rapid climate change. "Invasive genes" (into new species and populations) need to be recognized for their positive creative potential and addressed in conservation programs. "Genetic rescue" via hybrid translocations may provide needed adaptive flexibility for rapid adaptation to environmental change. While concerns persist for some conservationists, this review emphasizes the positive aspects of hybrids and hybridization. Specific implications of natural genetic introgression are addressed with a few examples from butterflies, including transgressive phenotypes and climate-driven homoploid recombinant hybrid speciation. Some specific examples illustrate these points using the swallowtail butterflies (Papilionidae) with their long-term historical data base (phylogeographical diversity changes) and recent (3-decade) climate-driven temporal and genetic divergence in recombinant homoploid hybrids and relatively recent hybrid speciation of Papilio appalachiensis in North America. Climate-induced "reshuffling" (recombinations) of species composition, genotypes, and genomes may become

  19. Gel spinning of PVA composite fibers with high content of multi-walled carbon nanotubes and graphene oxide hybrids

    International Nuclear Information System (INIS)

    Wei, Yizhe; Lai, Dengpan; Zou, Liming; Ling, Xinlong; Lu, Hongwei; Xu, Yongjing

    2015-01-01

    In this report, poly (vinyl alcohol) (PVA) composite fibers with high content of multi-walled carbon nanotubes and graphene oxide (MWCNTs-GO) hybrids were prepared by gel spinning, and were characterized by TGA, DSC, SEM, XL-2 yarn strength tester and electrical conductivity measurement. The total content of MWCNTs-GO hybrids in the PVA composite fibers, which is up to 25 wt%, was confirmed by TGA analysis. The DSC measurement shows that the melting and crystallization peaks decreased after the addition of nano-fillers. This is due to the reason that the motion of PVA chains is completely confined by strong hydrogen bonding interaction between PVA and nano-fillers. After the addtion of GO, the dispersibility of MWCNTs in composite fibers improved slightly. And the tensile strength and Young's modulus increased by 38% and 67%, respectively. This is caused by the increased hydrogen bonding interaction and synergistic effect through hybridization of MWCNTs and GO. More significantly, the electrical conductivity of PVA/MWCNTs/GO composite fibers enhanced by three orders of magnitude with the addition of GO. (paper)

  20. Performance Analysis of Solar-Wind-Diesel-Battery Hybrid Energy System for KLIA Sepang Station of Malaysia

    Science.gov (United States)

    Shezan, S. K. A.; Saidur, R.; Hossain, A.; Chong, W. T.; Kibria, M. A.

    2015-09-01

    A large number of populations of the world live in rural or remote areas those are geographically isolated. Power supply and uninterrupted fuel transportation to produce electrical power for these remote areas poses a great challenge. Using renewable energy in hybrid energy system might be a pathway to solve this problem. Malaysia is a large hilly land with the gift of renewable energy resources. There is a good chance to utilize these renewable resources to produce electrical power and to limit the dependency on the fossil fuel as well as reduce the carbon emissions. In this perspective, a research is carried out to analyze the performance of a solar-wind-diesel-battery hybrid energy system for a remote area named “KLIA Sepang station” in the state of Selangor, Malaysia. In this study, a 56 kW hybrid energy system has been proposed that is capable to support more than 50 households and 6 shops in that area. Real time field data of solar radiation and wind speed is used for the simulation and optimization of operations using “Homer” renewable energy software. The proposed system can reduce CO2 emission by about 16 tons per year compared to diesel generator only. In the same time the Cost of energy (COE) of the optimized system is USD 5.126/kWh.The proposed hybrid energy system might be applicable for other parts of the world where the climate conditions are similar.

  1. A Novel Type of Battery-Supercapacitor Hybrid Device with Highly Switchable Dual Performances Based on a Carbon Skeleton/Mg2Ni Free-Standing Hydrogen Storage Electrode.

    Science.gov (United States)

    Li, Na; Du, Yi; Feng, Qing-Ping; Huang, Gui-Wen; Xiao, Hong-Mei; Fu, Shao-Yun

    2017-12-27

    The sharp proliferation of high power electronics and electrical vehicles has promoted growing demands for power sources with both high energy and power densities. Under these circumstances, battery-supercapacitor hybrid devices are attracting considerable attention as they combine the advantages of both batteries and supercapacitors. Here, a novel type of hybrid device based on a carbon skeleton/Mg 2 Ni free-standing electrode without the traditional nickel foam current collector is reported, which has been designed and fabricated through a dispersing-freeze-drying method by employing reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNTs) as a hybrid skeleton. As a result, the Mg 2 Ni alloy is able to deliver a high discharge capacity of 644 mAh g -1 and, more importantly, a high cycling stability with a retention of over 78% after 50 charge/discharge cycles have been achieved, which exceeds almost all the results ever reported on the Mg 2 Ni alloy. Simultaneously, the electrode could also exhibit excellent supercapacitor performances including high specific capacities (296 F g -1 ) and outstanding cycling stability (100% retention after 100 cycles). Moreover, the hybrid device can switch between battery and supercapacitor modes immediately as needed during application. These features make the C skeleton/alloy electrode a highly promising candidate for battery-supercapacitor hybrid devices with high power/energy density and favorable cycling stability.

  2. Effects of elevated ozone, carbon dioxide, and the combination of both on the grain quality of Chinese hybrid rice

    International Nuclear Information System (INIS)

    Wang, Yunxia; Song, Qiling; Frei, Michael; Shao, Zaisheng; Yang, Lianxin

    2014-01-01

    The effects of CO 2 and/or O 3 elevation on rice grain quality were investigated in chamber experiments with gas fumigation performed from transplanting until maturity in 2011 and 2012. Compared with the control (current CO 2 and O 3 concentration), elevated CO 2 caused a tendency of an increase in grain chalkiness and a decrease in mineral nutrient concentrations. In contrast, elevated O 3 significantly increased grain chalkiness and the concentrations of essential nutrients, while changes in starch pasting properties indicated a trend of deterioration in the cooking and eating quality. In the combination of elevated CO 2 and O 3 treatment, only chalkiness degree was significantly affected. It is concluded that the O 3 concentration projected for the coming few decades will have more substantial effects on grain quality of Chinese hybrid rice than the projected high CO 2 concentration alone, and the combination of two gases caused fewer significant changes in grain quality than individual gas treatments. - Highlights: • We investigated the effects of carbon dioxide and/or ozone elevation on rice grain quality. • Elevated ozone concentration had substantial effects on grain quality under current carbon dioxide concentration. • Elevated carbon dioxide concentration mitigated the impact of elevated ozone concentration on rice grain quality. - Exposure of Chinese hybrid rice to elevated ozone and CO 2 during growth causes fewer changes in grain quality than ozone exposure alone

  3. Characterization of the emissions impacts of hybrid excavators with a portable emissions measurement system (PEMS)-based methodology.

    Science.gov (United States)

    Cao, Tanfeng; Russell, Robert L; Durbin, Thomas D; Cocker, David R; Burnette, Andrew; Calavita, Joseph; Maldonado, Hector; Johnson, Kent C

    2018-04-13

    Hybrid engine technology is a potentially important strategy for reduction of tailpipe greenhouse gas (GHG) emissions and other pollutants that is now being implemented for off-road construction equipment. The goal of this study was to evaluate the emissions and fuel consumption impacts of electric-hybrid excavators using a Portable Emissions Measurement System (PEMS)-based methodology. In this study, three hybrid and four conventional excavators were studied for both real world activity patterns and tailpipe emissions. Activity data was obtained using engine control module (ECM) and global positioning system (GPS) logged data, coupled with interviews, historical records, and video. This activity data was used to develop a test cycle with seven modes representing different types of excavator work. Emissions data were collected over this test cycle using a PEMS. The results indicated the HB215 hybrid excavator provided a significant reduction in tailpipe carbon dioxide (CO 2 ) emissions (from -13 to -26%), but increased diesel particulate matter (PM) (+26 to +27%) when compared to a similar model conventional excavator over the same duty cycle. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Recent Changes in Global Photosynthesis and Terrestrial Ecosystem Respiration Constrained From Multiple Observations

    Science.gov (United States)

    Li, Wei; Ciais, Philippe; Wang, Yilong; Yin, Yi; Peng, Shushi; Zhu, Zaichun; Bastos, Ana; Yue, Chao; Ballantyne, Ashley P.; Broquet, Grégoire; Canadell, Josep G.; Cescatti, Alessandro; Chen, Chi; Cooper, Leila; Friedlingstein, Pierre; Le Quéré, Corinne; Myneni, Ranga B.; Piao, Shilong

    2018-01-01

    To assess global carbon cycle variability, we decompose the net land carbon sink into the sum of gross primary productivity (GPP), terrestrial ecosystem respiration (TER), and fire emissions and apply a Bayesian framework to constrain these fluxes between 1980 and 2014. The constrained GPP and TER fluxes show an increasing trend of only half of the prior trend simulated by models. From the optimization, we infer that TER increased in parallel with GPP from 1980 to 1990, but then stalled during the cooler periods, in 1990-1994 coincident with the Pinatubo eruption, and during the recent warming hiatus period. After each of these TER stalling periods, TER is found to increase faster than GPP, explaining a relative reduction of the net land sink. These results shed light on decadal variations of GPP and TER and suggest that they exhibit different responses to temperature anomalies over the last 35 years.

  5. Platinum-TM (TM = Fe, Co) alloy nanoparticles dispersed nitrogen doped (reduced graphene oxide-multiwalled carbon nanotube) hybrid structure cathode electrocatalysts for high performance PEMFC applications.

    Science.gov (United States)

    Vinayan, B P; Ramaprabhu, S

    2013-06-07

    The efforts to push proton exchange membrane fuel cells (PEMFC) for commercial applications are being undertaken globally. In PEMFC, the sluggish kinetics of oxygen reduction reactions (ORR) at the cathode can be improved by the alloying of platinum with 3d-transition metals (TM = Fe, Co, etc.) and with nitrogen doping, and in the present work we have combined both of these aspects. We describe a facile method for the synthesis of a nitrogen doped (reduced graphene oxide (rGO)-multiwalled carbon nanotubes (MWNTs)) hybrid structure (N-(G-MWNTs)) by the uniform coating of a nitrogen containing polymer over the surface of the hybrid structure (positively surface charged rGO-negatively surface charged MWNTs) followed by the pyrolysis of these (rGO-MWNTs) hybrid structure-polymer composites. The N-(G-MWNTs) hybrid structure is used as a catalyst support for the dispersion of platinum (Pt), platinum-iron (Pt3Fe) and platinum-cobalt (Pt3Co) alloy nanoparticles. The PEMFC performances of Pt-TM alloy nanoparticle dispersed N-(G-MWNTs) hybrid structure electrocatalysts are 5.0 times higher than that of commercial Pt-C electrocatalysts along with very good stability under acidic environment conditions. This work demonstrates a considerable improvement in performance compared to existing cathode electrocatalysts being used in PEMFC and can be extended to the synthesis of metal, metal oxides or metal alloy nanoparticle decorated nitrogen doped carbon nanostructures for various electrochemical energy applications.

  6. Well-to-wheels life-cycle analysis of alternative fuels and vehicle technologies in China

    International Nuclear Information System (INIS)

    Shen Wei; Han Weijian; Chock, David; Chai Qinhu; Zhang Aling

    2012-01-01

    A well-to-wheels life cycle analysis on total energy consumptions and greenhouse-gas (GHG) emissions for alternative fuels and accompanying vehicle technologies has been carried out for the base year 2010 and projected to 2020 based on data gathered and estimates developed for China. The fuels considered include gasoline, diesel, natural gas, liquid fuels from coal conversion, methanol, bio-ethanol and biodiesel, electricity and hydrogen. Use of liquid fuels including methanol and Fischer–Tropsch derived from coal will significantly increase GHG emissions relative to use of conventional gasoline. Use of starch-based bio-ethanol will incur a substantial carbon disbenefit because of the present highly inefficient agricultural practice and plant processing in China. Electrification of vehicles via hybrid electric, plug-in hybrid electric (PHEV) and battery electric vehicle technologies offers a progressively improved prospect for the reduction of energy consumption and GHG emission. However, the long-term carbon emission reduction is assured only when the needed electricity is generated by zero- or low-carbon sources, which means that carbon capture and storage is a necessity for fossil-based feedstocks. A PHEV that runs on zero- or low-carbon electricity and cellulosic ethanol may be one of the most attractive fuel-vehicle options in a carbon-constrained world. - Highlights: ► Data and estimates unique to China are used in this analysis. ► Use of starch-based bio-ethanol will incur a substantial carbon disbenefit in China. ► Use of methanol derived from coal will incur even more carbon disbenefit. ► Plug-in-hybrid with cellulosic ethanol and clean electricity may be a viable option.

  7. 700 F hybrid capacitors cells composed of activated carbon and Li4Ti5O12 microspheres with ultra-long cycle life

    Science.gov (United States)

    Ruan, Dianbo; Kim, Myeong-Seong; Yang, Bin; Qin, Jun; Kim, Kwang-Bum; Lee, Sang-Hyun; Liu, Qiuxiang; Tan, Lei; Qiao, Zhijun

    2017-10-01

    To address the large-scale application demands of high energy density, high power density, and long cycle lifetime, 700-F hybrid capacitor pouch cells have been prepared, comprising ∼240-μm-thick activated carbon cathodes, and ∼60-μm-thick Li4Ti5O12 anodes. Microspherical Li4Ti5O12 (M-LTO) synthesized by spray-drying features 200-400 nm primary particles and interconnected nanopore structures. M-LTO half-cells exhibits high specific capacities (175 mAhh g-1), good rate capabilities (148 mAhh g-1 at 20 C), and ultra-long cycling stabilities (90% specific capacity retention after 10,000 cycles). In addition, the obtained hybrid capacitors comprising activated carbon (AC) and M-LTO shows excellent cell performances, achieving a maximum energy density of 51.65 Wh kg-1, a maximum power density of 2466 W kg-1, and ∼92% capacitance retention after 10,000 cycles, thus meeting the demands for large-scale applications such as trolleybuses.

  8. Real-world fuel economy and CO2 emissions of plug-in hybrid electric vehicles

    International Nuclear Information System (INIS)

    Ploetz, Patrick; Funke, Simon Arpad; Jochem, Patrick

    2015-01-01

    Plug-in hybrid electric vehicles (PHEV) combine electric propulsion with an internal combustion engine. Their potential to reduce transport related green-house gas emissions highly depends on their actual usage and electricity provision. Various studies underline their environmental and economic advantages, but are based on standardised driving cycles, simulations or small PHEV fleets. Here, we analyse real-world fuel economy of PHEV and the factors influencing it based on about 2,000 actual PHEV that have been observed over more than a year in the U.S. and Germany. We find that real-world fuel economy of PHEV differ widely among users. The main factors explaining this variation are the annual mileage, the regularity of daily driving, and the likelihood of long-distance trips. Current test cycle fuel economy ratings neglect these factors. Despite the broad range of PHEV fuel economies, the test cycle fuel economy ratings can be close to empiric PHEV fleet averages if the average annual mile-age is about 17,000 km. For the largest group of PHEV in our data, the Chevrolet Volt, we find the average fuel economy to be 1.45 litres/100 km at an average electric driving share of 78%. The resulting real-world tank-to-wheel CO 2 emissions of these PHEV are 42 gCO 2 /km and the annual CO 2 savings in the U.S. amount to about 50 Mt. In conclusion, the variance of empirical PHEV fuel economy is considerably higher than of conventional vehicles. This should be taken into account by future test cycles and high electric driving shares should be incentivised.

  9. Behavioural isolation may facilitate homoploid hybrid speciation in cichlid fish

    NARCIS (Netherlands)

    Selz, O. M.; Thommen, R.; Maan, M. E.; Seehausen, O.

    Hybrid speciation is constrained by the homogenizing effects of gene flow from the parental species. In the absence of post-mating isolation due to structural changes in the genome, or temporal or spatial premating isolation, another form of reproductive isolation would be needed for homoploid

  10. A facile one-pot fabrication of polyphosphazene microsphere/carbon fiber hybrid reinforcement and its effect on the interfacial adhesion of epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xiang [Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); School of Mechanical and Electronic Engineering, Ningbo Dahongying University, Ningbo 315175 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Xu, Haibing, E-mail: xuhaibing@nimte.ac.cn [Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Liu, Dong; Yan, Chun [Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China); Zhu, Yingdan, E-mail: y.zhu@nimte.ac.cn [Zhejiang Provincial Key Laboratory of Robotics and Intelligent Manufacturing Equipment Technology, Ningbo Institute of Material Technology and Engineering, Chinese Academy of Science, Ningbo 315201 (China)

    2017-07-15

    Graphical abstract: Carbon fiber was successfully functionalized with a layer of coating and poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) microspheres (PZSMS) by in situ polymerization. The enhancement of surface roughness can improve obviously the interfacial properties through providing more contact points and increasing mechanical interlocking between carbon fiber and epoxy matrix. Moreover, the cyclomatrix-type polyphosphazene coating and PZSMS distributed on the fibers surface can heal the surface defects to some extent and assist in holding back or absorbing excessive stress, resulting in the improvement of tensile strength. - Highlights: • Polyphosphazene microspheres/CF hybrid reinforcements were prepared via a novel and facile one-pot in situ polymerization. • Plenty of poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) microspheres were introduced onto the CF surfaces. • The multi-scale hybrid CF reinforcement enhanced the interfacial adhesion of CF/epoxy composites obviously. • The tensile strength of multi-scale hybrid CF also showed an obvious increase. - Abstract: Introducing nanoscale reinforcements into the interface between carbon fiber (CF) and resin is an effective approach to improve the interfacial adhesion of CF composites. In this paper, a facile one-pot polymerization process provides a rapid and efficient method for preparing polyphosphazene microspheres/CF hybrid reinforcement using hexachlorocyclotriphosphazene (HCCP) and bis(4-hydroxyphenyl) sulfone (BPS) as monomers. By the in situ polymerization modification, HCCP and BPS were successfully cross-linked and deposited on the CF surface. Scanning electron microscope and atomic force microscopy images show that poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) microspheres were introduced onto the CF surfaces and the surface roughness of fibers is enhanced obviously. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirm that the

  11. A facile one-pot fabrication of polyphosphazene microsphere/carbon fiber hybrid reinforcement and its effect on the interfacial adhesion of epoxy composites

    International Nuclear Information System (INIS)

    Chen, Xiang; Xu, Haibing; Liu, Dong; Yan, Chun; Zhu, Yingdan

    2017-01-01

    Graphical abstract: Carbon fiber was successfully functionalized with a layer of coating and poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) microspheres (PZSMS) by in situ polymerization. The enhancement of surface roughness can improve obviously the interfacial properties through providing more contact points and increasing mechanical interlocking between carbon fiber and epoxy matrix. Moreover, the cyclomatrix-type polyphosphazene coating and PZSMS distributed on the fibers surface can heal the surface defects to some extent and assist in holding back or absorbing excessive stress, resulting in the improvement of tensile strength. - Highlights: • Polyphosphazene microspheres/CF hybrid reinforcements were prepared via a novel and facile one-pot in situ polymerization. • Plenty of poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) microspheres were introduced onto the CF surfaces. • The multi-scale hybrid CF reinforcement enhanced the interfacial adhesion of CF/epoxy composites obviously. • The tensile strength of multi-scale hybrid CF also showed an obvious increase. - Abstract: Introducing nanoscale reinforcements into the interface between carbon fiber (CF) and resin is an effective approach to improve the interfacial adhesion of CF composites. In this paper, a facile one-pot polymerization process provides a rapid and efficient method for preparing polyphosphazene microspheres/CF hybrid reinforcement using hexachlorocyclotriphosphazene (HCCP) and bis(4-hydroxyphenyl) sulfone (BPS) as monomers. By the in situ polymerization modification, HCCP and BPS were successfully cross-linked and deposited on the CF surface. Scanning electron microscope and atomic force microscopy images show that poly(cyclotriphosphazene-co-4,4′-sulfonyldiphonel) microspheres were introduced onto the CF surfaces and the surface roughness of fibers is enhanced obviously. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirm that the

  12. Vacuum infusion method for woven carbon/Kevlar reinforced hybrid composite

    Science.gov (United States)

    Hashim, N.; Majid, D. L.; Uda, N.; Zahari, R.; Yidris, N.

    2017-12-01

    The vacuum assisted resin transfer moulding (VaRTM) or Vacuum Infusion (VI) is one of the fabrication methods used for composite materials. Compared to other methods, this process costs lower than using prepregs because it does not need to use the autoclave to cure. Moreover, composites fabricated using this VI method exhibit superior mechanical properties than those made through hand layup process. In this study, the VI method is used in fabricating woven carbon/Kevlar fibre cloth with epoxy matrix. This paper reports the detailed methods on fabricating the hybrid composite using VI process and several precautions that need to be taken to avoid any damage to the properties of the composite material. The result highlights that the successfully fabricated composite has approximately 60% of fibres weight fraction. Since the composites produced by the VI process have a higher fibre percentage, this process should be considered for composites used in applications that are susceptible to the conditions where the fibres need to be the dominant element such as in tension loading.

  13. Hybrid Carbon Fibers/Carbon Nanotubes Structures for Next Generation Polymeric Composites

    Directory of Open Access Journals (Sweden)

    M. Al-Haik

    2010-01-01

    Full Text Available Pitch-based carbon fibers are commonly used to produce polymeric carbon fiber structural composites. Several investigations have reported different methods for dispersing and subsequently aligning carbon nanotubes (CNTs as a filler to reinforce polymer matrix. The significant difficulty in dispersing CNTs suggested the controlled-growth of CNTs on surfaces where they are needed. Here we compare between two techniques for depositing the catalyst iron used toward growing CNTs on pitch-based carbon fiber surfaces. Electrochemical deposition of iron using pulse voltametry is compared to DC magnetron iron sputtering. Carbon nanostructures growth was performed using a thermal CVD system. Characterization for comparison between both techniques was compared via SEM, TEM, and Raman spectroscopy analysis. It is shown that while both techniques were successful to grow CNTs on the carbon fiber surfaces, iron sputtering technique was capable of producing more uniform distribution of iron catalyst and thus multiwall carbon nanotubes (MWCNTs compared to MWCNTs grown using the electrochemical deposition of iron.

  14. Eco-efficient based logistics network design in hybrid manufacturing/ remanufacturing system in low-carbon economy

    Directory of Open Access Journals (Sweden)

    Yacan Wang

    2013-03-01

    Full Text Available Purpose: Low-carbon economy requires the pursuit of eco-efficiency, which is a win-win situation between economic and environmental efficiency. In this paper the question of trading off the economic and environmental effects embodied in eco-efficiency in the hybrid manufacturing/remanufacturing logistics network design in the context of low-carbon economy is examined.Design/methodology/approach: A multi-objective mixed integer linear programming model to find the optimal facility locations and materials flow allocation is established. In the objective function, three minimum targets are set: economic cost, CO2 emission and waste generation. Through an iterative algorithm, the Pareto Boundary of the problem is obtained.Findings: The results of numeric study show that in order to achieve a Pareto improvement over an original system, three of the critical rates (i.e. return rate, recovery rate, and cost substitute rate should be increased.Practical implications: To meet the need of low-carbon dioxide, an iso- CO2 emission curve in which decision makers have a series of optimal choices with the same CO2 emission but different cost and waste generation is plotted. Each choice may have different network design but all of these are Pareto optimal solutions, which provide a comprehensive evaluation of both economics and ecology for the decision making.Originality/value: This research chooses carbon emission as one of the three objective functions and uses Pareto sets to analyze how to balance profitability and environmental impacts in designing remanufacturing closed-loop supply chain in the context of low-carbon economy.

  15. Novel Carbon Materials in the Cathode Formulation for High Rate Rechargeable Hybrid Aqueous Batteries

    Directory of Open Access Journals (Sweden)

    Xiao Zhu

    2017-11-01

    Full Text Available Novel carbon materials, carbon nanotubes (CNTs and porous graphene (PG, were exploited and used as conductive additives to improve the rate performance of LiMn2O4 cathode for the rechargeable aqueous Zn/LiMn2O4 battery, namely the rechargeable hybrid aqueous battery (ReHAB. Thanks to the long-range conductivity and stable conductive network provided by CNTs, the rate and cycling performances of LiMn2O4 cathode in ReHAB are highly improved—up to about 100 mAh·g−1 capacity is observed at 10 C (1 C = 120 mAh·g−1. Except for CNTs, porous graphene (PG with a high surface area, an abundant porous structure, and an excellent electrical conductivity facilitates the transportation of Li ions and electrons, which can also obviously enhance the rate capability of the ReHAB. This is important because the ReHAB could be charged/discharged in a few minutes, and this leads to potential application of the ReHAB in automobile industry.

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

    Science.gov (United States)

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

    2015-12-01

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

  17. The global carbon cycle

    International Nuclear Information System (INIS)

    Maier-Reimer, E.

    1991-01-01

    Basic concepts of the global carbon cycle on earth are described; by careful analyses of isotopic ratios, emission history and oceanic ventilation rates are derived, which provide crucial tests for constraining and calibrating models. Effects of deforestation, fertilizing, fossil fuel burning, soil erosion, etc. are quantified and compared, and the oceanic carbon process is evaluated. Oceanic and terrestrial biosphere modifications are discussed and a carbon cycle model is proposed

  18. Direct electrochemistry with enhanced electrocatalytic activity of hemoglobin in hybrid modified electrodes composed of graphene and multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wei, E-mail: swyy26@hotmail.com [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 China (China); College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Cao, Lili; Deng, Ying; Gong, Shixing [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Shi, Fan; Li, Gaonan; Sun, Zhenfan [College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158 China (China)

    2013-06-05

    Graphical abstract: -- Highlights: •A graphene and multi-walled carbon nanotubes nanocomposite was prepared. •Hemoglobin and nanocomposite modified carbon ionic liquid electrode was fabricated. •Direct electrochemistry of hemoglobin was realized on the modified electrode. •Bioelectrocatalysis towards the reduction of different substrates was enhanced. -- Abstract: A graphene (GR) and multi-walled carbon nanotubes (MWCNT) hybrid was prepared and modified on a 1-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE). Hemoglobin (Hb) was immobilized on GR-MWCNT/CILE surface with Nafion as the film forming material and the modified electrode was denoted as Nafion/Hb-GR-MWCNT/CILE. Spectroscopic results revealed that Hb molecules retained its native structure in the GR-MWCNT hybird. Electrochemical behaviors of Hb were carefully investigated by cyclic voltammetry with a pair of well-defined redox peaks obtained, which indicated that direct electron transfer of Hb was realized in the hybrid modified electrode. The result could be attributed to the synergistic effects of GR-MWCNT hybrid with enlarged surface area and improved conductivity through the formation of a three-dimensional network. Electrochemical parameters of the immobilized Hb on the electrode surface were further calculated with the results of the electron transfer number (n) as 1.03, the charge transfer coefficient (a) as 0.58 and the electron-transfer rate constant (k{sub s}) as 0.97 s{sup −1}. The Hb modified electrode showed good electrocatalytic ability toward the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.05 to 38.0 mmol L{sup −1} with a detection limit of 0.0153 mmol L{sup −1} (3σ), H{sub 2}O{sub 2} in the concentration range from 0.1 to 516.0 mmol L{sup −1} with a detection limit of 34.9 nmol/L (3σ) and NaNO{sub 2} in the concentration range from 0.5 to 650.0 mmol L{sup −1} with a detection limit of 0

  19. Direct electrochemistry with enhanced electrocatalytic activity of hemoglobin in hybrid modified electrodes composed of graphene and multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Sun, Wei; Cao, Lili; Deng, Ying; Gong, Shixing; Shi, Fan; Li, Gaonan; Sun, Zhenfan

    2013-01-01

    Graphical abstract: -- Highlights: •A graphene and multi-walled carbon nanotubes nanocomposite was prepared. •Hemoglobin and nanocomposite modified carbon ionic liquid electrode was fabricated. •Direct electrochemistry of hemoglobin was realized on the modified electrode. •Bioelectrocatalysis towards the reduction of different substrates was enhanced. -- Abstract: A graphene (GR) and multi-walled carbon nanotubes (MWCNT) hybrid was prepared and modified on a 1-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE). Hemoglobin (Hb) was immobilized on GR-MWCNT/CILE surface with Nafion as the film forming material and the modified electrode was denoted as Nafion/Hb-GR-MWCNT/CILE. Spectroscopic results revealed that Hb molecules retained its native structure in the GR-MWCNT hybird. Electrochemical behaviors of Hb were carefully investigated by cyclic voltammetry with a pair of well-defined redox peaks obtained, which indicated that direct electron transfer of Hb was realized in the hybrid modified electrode. The result could be attributed to the synergistic effects of GR-MWCNT hybrid with enlarged surface area and improved conductivity through the formation of a three-dimensional network. Electrochemical parameters of the immobilized Hb on the electrode surface were further calculated with the results of the electron transfer number (n) as 1.03, the charge transfer coefficient (a) as 0.58 and the electron-transfer rate constant (k s ) as 0.97 s −1 . The Hb modified electrode showed good electrocatalytic ability toward the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.05 to 38.0 mmol L −1 with a detection limit of 0.0153 mmol L −1 (3σ), H 2 O 2 in the concentration range from 0.1 to 516.0 mmol L −1 with a detection limit of 34.9 nmol/L (3σ) and NaNO 2 in the concentration range from 0.5 to 650.0 mmol L −1 with a detection limit of 0.282 μmol L −1 (3σ). So the proposed

  20. Diffusion-type model of the global carbon cycle for the estimation of dose to the world population from releases of carbon-14 to the atmosphere

    International Nuclear Information System (INIS)

    Killough, G.G.

    1977-05-01

    A nonlinear dynamic model of the exchange of carbon among the atmosphere, terrestrial biosphere, and ocean is described and applied to estimating the radiation dose to the world's population from the release of 14 C to the atmosphere from the nuclear power industry. A computer implementation of the model, written in the IBM Continuous System Modeling Program III (CSMP III) simulation language, is presented. The model treats the ocean as a diffusive medium with respect to vertical transport of carbon, and the nonlinear variation of CO 2 partial pressure with the total inorganic carbon concentration in surface waters is taken into account in calculating the transfer rate from ocean to atmosphere. Transfers between the atmosphere and terrestrial biosphere are represented by nonlinear equations which consider CO 2 fertilization and impose a constraint on the ultimate total carbon mass in the biosphere

  1. Complex Hybrid Inflation and Baryogenesis

    OpenAIRE

    Delepine, David; Martinez, Carlos; Urena-Lopez, L. Arturo

    2006-01-01

    We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vev of the waterfall field, which is well constrained by diverse cosmological observations.

  2. A Techno-Economic Assessment of Hybrid Cooling Systems for Coal- and Natural-Gas-Fired Power Plants with and without Carbon Capture and Storage.

    Science.gov (United States)

    Zhai, Haibo; Rubin, Edward S

    2016-04-05

    Advanced cooling systems can be deployed to enhance the resilience of thermoelectric power generation systems. This study developed and applied a new power plant modeling option for a hybrid cooling system at coal- or natural-gas-fired power plants with and without amine-based carbon capture and storage (CCS) systems. The results of the plant-level analyses show that the performance and cost of hybrid cooling systems are affected by a range of environmental, technical, and economic parameters. In general, when hot periods last the entire summer, the wet unit of a hybrid cooling system needs to share about 30% of the total plant cooling load in order to minimize the overall system cost. CCS deployment can lead to a significant increase in the water use of hybrid cooling systems, depending on the level of CO2 capture. Compared to wet cooling systems, widespread applications of hybrid cooling systems can substantially reduce water use in the electric power sector with only a moderate increase in the plant-level cost of electricity generation.

  3. High-rate nano-crystalline Li{sub 4}Ti{sub 5}O{sub 12} attached on carbon nano-fibers for hybrid supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Naoi, Katsuhiko; Isobe, Yusaku; Aoyagi, Shintaro [Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8558 (Japan); Ishimoto, Shuichi [Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8558 (Japan); Nippon Chemi-Con Corporation, 363 Arakawa, Takahagi-shi, Ibaraki 318-8505 (Japan)

    2010-09-15

    A lithium titanate (Li{sub 4}Ti{sub 5}O{sub 12})-based electrode which can operate at unusually high current density (300 C) was developed as negative electrode for hybrid capacitors. The high-rate Li{sub 4}Ti{sub 5}O{sub 12} electrode has a unique nano-structure consisting of unusually small nano-crystalline Li{sub 4}Ti{sub 5}O{sub 12} (ca. 5-20 nm) grafted onto carbon nano-fiber anchors (nc-Li{sub 4}Ti{sub 5}O{sub 12}/CNF). This nano-structured nc-Li{sub 4}Ti{sub 5}O{sub 12}/CNF composite are prepared by simple sol-gel method under ultra-centrifugal force (65,000 N) followed by instantaneous annealing at 900 C for 3 min. A model hybrid capacitor cell consisting of a negative nc-Li{sub 4}Ti{sub 5}O{sub 12}/CNF composite electrode and a positive activated carbon electrode showed high energy density of 40 Wh L{sup -1} and high power density of 7.5 kW L{sup -1} comparable to conventional EDLCs. (author)

  4. Revealing the synergetic effects in Ni nanoparticle-carbon nanotube hybrids by scanning transmission X-ray microscopy and their application in the hydrolysis of ammonia borane.

    Science.gov (United States)

    Zhao, Guanqi; Zhong, Jun; Wang, Jian; Sham, Tsun-Kong; Sun, Xuhui; Lee, Shuit-Tong

    2015-06-07

    The hybrids of carbon nanotubes (CNTs) and the supported Ni nanoparticles (NPs) have been studied by scanning transmission X-ray microscopy (STXM) and tested by the hydrolysis reaction of ammonia borane (AB, NH3BH3). Data clearly showed the existence of a strong interaction between Ni NPs and thin CNTs (C-O-Ni bonds), which favored the tunable (buffer) electronic structure of Ni NPs facilitating the catalytic process. The hydrolysis process of AB confirmed the hypothesis that the hybrids with a strong interfacial interaction would show superior catalytic performance, while the hybrids with a weak interfacial interaction show poor performance. Our results provide a wealth of detailed information regarding the electronic structure of the NP-CNT hybrids and provide guidance towards the rational design of high-performance catalysts for energy applications.

  5. Hybrid Combustion-Gasification Chemical Looping

    Energy Technology Data Exchange (ETDEWEB)

    Herbert Andrus; Gregory Burns; John Chiu; Gregory Lijedahl; Peter Stromberg; Paul Thibeault

    2009-01-07

    For the past several years Alstom Power Inc. (Alstom), a leading world-wide power system manufacturer and supplier, has been in the initial stages of developing an entirely new, ultra-clean, low cost, high efficiency power plant for the global power market. This new power plant concept is based on a hybrid combustion-gasification process utilizing high temperature chemical and thermal looping technology The process consists of the oxidation, reduction, carbonation, and calcination of calcium-based compounds, which chemically react with coal, biomass, or opportunity fuels in two chemical loops and one thermal loop. The chemical and thermal looping technology can be alternatively configured as (i) a combustion-based steam power plant with CO{sub 2} capture, (ii) a hybrid combustion-gasification process producing a syngas for gas turbines or fuel cells, or (iii) an integrated hybrid combustion-gasification process producing hydrogen for gas turbines, fuel cells or other hydrogen based applications while also producing a separate stream of CO{sub 2} for use or sequestration. In its most advanced configuration, this new concept offers the promise to become the technology link from today's Rankine cycle steam power plants to tomorrow's advanced energy plants. The objective of this work is to develop and verify the high temperature chemical and thermal looping process concept at a small-scale pilot facility in order to enable AL to design, construct and demonstrate a pre-commercial, prototype version of this advanced system. In support of this objective, Alstom and DOE started a multi-year program, under this contract. Before the contract started, in a preliminary phase (Phase 0) Alstom funded and built the required small-scale pilot facility (Process Development Unit, PDU) at its Power Plant Laboratories in Windsor, Connecticut. Construction was completed in calendar year 2003. The objective for Phase I was to develop the indirect combustion loop with CO{sub 2

  6. Exploring world art

    NARCIS (Netherlands)

    Venbrux, H.J.M.; Rosi, P.; Welsch, R.L.

    2006-01-01

    The contemporary visual arts of non-Western peoples are increasingly part of a capitalistic, global art world with diverse gatekeepers, tastes, venues, individuation of artists, and hybrid sources of inspiration. In this collection, ethnographic case studies from around the globe are used to examine

  7. In Situ Production of Graphene-Fiber Hybrid Structures

    DEFF Research Database (Denmark)

    Akia, Mandana; Cremar, Lee; Chipara, Mircea

    2017-01-01

    We report a scalable method to obtain a new material where large graphene sheets form webs linking carbon fibers. Film-fiber hybrid nonwoven mats are formed during fiber processing and converted to carbon structures after a simple thermal treatment. This contrasts with multistep methods...... that attempt to mix previously prepared graphene and fibers, or require complicated and costly processes for deposition of graphene over carbon fibers. The developed graphene-fiber hybrid structures have seamless connections between graphene and fibers, and in fact the graphene "veils" extend directly from one...... a capillarity effect that promoted the formation of thin veils, which become graphene sheets upon dehydration by sulfuric acid vapor followed by carbonization (at relatively low temperatures, below 800 °C). These veils extend over several micrometers within the pores of the fiber network, and consist...

  8. Trading scheme 'key' to low-carbon economy

    International Nuclear Information System (INIS)

    2006-01-01

    Federal Opposition Leader Kim Beazley has emphasised the importance of getting the economics of environmental policy right by introducing market-based mechanisms for pricing emissions. 'Market-based mechanisms such as emissions trading are central to moving to a low-carbon economy,' he said in his latest blueprint. 'A functioning carbon market will deliver a price signal, so there is a long-term incentive to cut emissions further, and a mechanism for trading, so that energy can be allocated efficiently in the economy. It will also encourage greater private investment in clean energy technology.' Mr Beazley said the new market would also reward the many companies who were already adapting to a carbon-constrained world. 'This includes those global companies in Australia that already operate in emissions trading markets overseas. An effective price signal for carbon in Australia will allow these companies to benefit directly from their good corporate citizenship and long-term vision.' Mr Beazley has committed a federal Labor government to work with state governments and business to establish the national trading scheme. He also criticised the Federal Government for refusing to ratify the Kyoto Protocol, which he argued excluded Australian businesses from participating in the emerging global carbon trade. This made it harder for businesses to break into the market for cleaner production technologies overseas. While again admitting Kyoto was not perfect, Mr Beazley said ratification would see Australia part of what would potentially be 'the biggest market in the world by 2020'. He said the recent Asia Pacific Climate Change Pact was a positive step but was not an alternative to Kyoto. 'Above all, it has no economic mechanisms to drive further change. 'Without ratifying Kyoto some of our businesses are missing out on effective participation in international schemes that offer substantial financial rewards for greenhouse gas reductions. 'By ratifying Kyoto and adopting

  9. Synthesis, Characterization and Utility of Carbon Nanotube Based Hybrid Sensors in Bioanalytical Applications

    Science.gov (United States)

    Badhulika, Sushmee

    The detection of gaseous analytes and biological molecules is of prime importance in the fields of environmental pollution control, food and water - safety and analysis; and medical diagnostics. This necessitates the development of advanced and improved technology that is reliable, inexpensive and suitable for high volume production. The conventional sensors are often thin film based which lack sensitivity due to the phenomena of current shunting across the charge depleted region when an analyte binds with them. One dimensional (1-D) nanostructures provide a better alternative for sensing applications by eliminating the issue of current shunting due to their 1-D geometries and facilitating device miniaturization and low power operations. Carbon nanotubes (CNTs) are 1-D nanostructures that possess small size, high mechanical strength, high electrical and thermal conductivity and high specific area that have resulted in their wide spread applications in sensor technology. To overcome the issue of low sensitivity of pristine CNTs and to widen their scope, hybrid devices have been fabricated that combine the synergistic properties of CNTs along with materials like metals and conducting polymers (CPs). CPs exhibit electronic, magnetic and optical properties of metals and semiconductors while retaining the processing advantages of polymers. Their high chemical sensitivity, room temperature operation and tunable charge transport properties has made them ideal for use as transducing elements in chemical sensors. In this dissertation, various CNT based hybrid devices such as CNT-conducting polymer and graphene-CNT-metal nanoparticles based sensors have been developed and demonstrated towards bioanalytical applications such as detection of volatile organic compounds (VOCs) and saccharides. Electrochemical polymerization enabled the synthesis of CPs and metal nanoparticles in a simple, cost effective and controlled way on the surface of CNT based platforms thus resulting in

  10. Constraining the Q10 of respiration in water-limited environments

    Science.gov (United States)

    Collins, A.; Ryan, M. G.; Xu, C.; Grossiord, C.; Michaletz, S. T.; McDowell, N. G.

    2016-12-01

    If the current rate of greenhouse emissions remains constant over the next few decades, projections of climate change forecast increased atmospheric temperatures by a least 1.1°C by the end of the century. Warmer temperatures are expected to largely influence the exchange of energy, carbon and water between plants and the atmosphere. Several studies support that terrestrial ecosystems currently act as a major carbon sink, however warmer temperatures may amplify respiration processes and shift terrestrial ecosystems from a sink to a source of carbon in the future. Most Earth System Models incorporate the temperature dependence of plant respiration (Q10) to estimate and predict respiration processes and associated carbon fluxes. Using a temperature and precipitation manipulation experiment in natural conditions, we present evidence that this parameter is poorly constrained especially in water-limited environments. We discuss the utility of the Q10 framework and suggest improvements for this parameter along with trait-based approaches to better resolve models.

  11. Zirconium-carbon hybrid sorbent for removal of fluoride from water: oxalic acid mediated Zr(IV) assembly and adsorption mechanism

    Science.gov (United States)

    Halla, Velazquez-Jimenez Litza; Hurt Robert, H; Juan, Matos; Rene, Rangel-Mendez Jose

    2014-01-01

    When activated carbon (AC) is modified with zirconium(IV) by impregnation or precipitation, the fluoride adsorption capacity is typically improved. There is significant potential to improve these hybrid sorbent by controlling the impregnation conditions, which determine the assembly and dispersion of the Zr phases on carbon surfaces. Here, commercial activated carbon was modified with Zr(IV) together with oxalic acid (OA) used to maximize the zirconium dispersion and enhance fluoride adsorption. Adsorption experiments were carried out at pH 7 and 25 °C with a fluoride concentration of 40 mg L−1. The OA/Zr ratio was varied to determine the optimal conditions for subsequent fluoride adsorption. The data was analyzed using the Langmuir and Freundlich isotherm models. FTIR, XPS and the surface charge distribution were performed to elucidate the adsorption mechanism. Potentiometric titrations showed that the modified activated carbon (ZrOx-AC) possesses positive charge at pH lower than 7, and FTIR analysis demonstrated that zirconium ions interact mainly with carboxylic groups on the activated carbon surfaces. Moreover, XPS analysis demonstrated that Zr(IV) interacts with oxalate ions, and the fluoride adsorption mechanism is likely to involve –OH− exchange from zirconyl oxalate complexes. PMID:24359079

  12. A simple chemical synthesis of amorphous carbon nanotubes–MnO{sub 2} flake hybrids for cold cathode application

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Sourav [Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata 700032 (India); Banerjee, Diptonil; Das, Nirmalya Sankar [School of Material Science and Nanotechnology, Jadavpur University, Kolkata 700032 (India); Chattopadhyay, Kalyan Kumar, E-mail: kalyan_chattopadhyay@yahoo.com [Thin Film and Nanoscience Laboratory, Department of Physics, Jadavpur University, Kolkata 700032 (India); School of Material Science and Nanotechnology, Jadavpur University, Kolkata 700032 (India)

    2015-08-30

    Highlights: • Amorphous carbon nanotubes (aCNTs) have been synthesized chemically. • The walls of the aCNTs have been anchored by MnO{sub 2} nanoflakes. • It is seen for the first time that MnO{sub 2} modified aCNTs show much better field emission property. • Experimental result has also been supported theoretically. • This can acts as doorstep to develop a new hybrid system as a novel cold cathode material. - Abstract: A simple approach has been implemented to synthesize amorphous carbon nanotubes (a-CNTs) and manganese oxide (MnO{sub 2}) hybrid nanostructure at temperature as low as ∼250 °C in open atmosphere. Microscopic studies of the samples revealed that the walls of the a-CNTs were coated uniformly by MnO{sub 2} nanoflakes. The composition of the as prepared sample was studied with the help of energy dispersive X-ray and X-ray photoelectron spectroscopy. Electron field emission study was done in a custom built high vacuum field emission setup for the prepared a-CNT and manganese oxide (MnO{sub 2}) hybrid nanostructure. It is seen that the performance of the a-CNTs as cold cathode emitter has been enhanced greatly when MnO{sub 2} nanoflakes were coated uniformly over it. The turn on field has been reduced from 7.17 to value as low as 3.82 V/mm with enhancement factor increases from 2428 to 6965. Finite element based simulation study theoretically confirms the enhancement of field emission properties of as prepared MnO{sub 2} nanoflake coated a-CNTs. The results have been explained due to enhanced surface roughness leading to higher enhancement factor and overall increase of emission sites.

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

    Science.gov (United States)

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

    2018-01-01

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

  14. Hybrid Wound Filaments for Greater Resistance to Impacts

    Science.gov (United States)

    DeLay, Thomas K.; Patterson, James E.; Olson, Michael A.

    2008-01-01

    A hybrid material containing wound filaments made of a hybrid of high-strength carbon fibers and poly(phenylene benzobisoxazole) [PBO] fibers is discussed. This hybrid material is chosen in an effort to increase the ability of the pressure vessel to resist damage by low-speed impacts (e.g., dropping of tools on the vessel or bumping of the vessel against hard objects during installation and use) without significantly increasing the weight of the vessel. While the basic concept of hybridizing fibers in filament-wound structures is not new, the use of hybridization to increase resistance to impacts is an innovation, and can be expected to be of interest in the composite-pressure-vessel industry. The precise types and the proportions of the high-strength carbon fibers and the PBO fibers in the hybrid are chosen, along with the filament-winding pattern, to maximize the advantageous effects and minimize the disadvantageous effects of each material. In particular, one seeks to (1) take advantage of the ability of the carbon fibers to resist stress rupture while minimizing their contribution to vulnerability of the vessel to impact damage and (2) take advantage of the toughness of the PBO fibers while minimizing their contribution to vulnerability of the vessel to stress rupture. Experiments on prototype vessels fabricated according to this concept have shown promising results. At the time of reporting the information for this article, research toward understanding and optimizing the performances of PBO fibers so as to minimize their contribution to vulnerability of the pressure vessel to stress rupture had yet to be performed.

  15. Using the World Health Organization's 4S-Framework to Strengthen National Strategies, Policies and Services to Address Mental Health Problems in Adolescents in Resource-Constrained Settings

    Directory of Open Access Journals (Sweden)

    Cabral de Mello Meena

    2011-09-01

    Full Text Available Abstract Background Most adolescents live in resource-constrained countries and their mental health has been less well recognised than other aspects of their health. The World Health Organization's 4-S Framework provides a structure for national initiatives to improve adolescent health through: gathering and using strategic information; developing evidence-informed policies; scaling up provision and use of health services; and strengthening linkages with other government sectors. The aim of this paper is to discuss how the findings of a recent systematic review of mental health problems in adolescents in resource-constrained settings might be applied using the 4-S Framework. Method Analysis of the implications of the findings of a systematic search of the English-language literature for national strategies, policies, services and cross-sectoral linkages to improve the mental health of adolescents in resource-constrained settings. Results Data are available for only 33/112 [29%] resource-constrained countries, but in all where data are available, non-psychotic mental health problems in adolescents are identifiable, prevalent and associated with reduced quality of life, impaired participation and compromised development. In the absence of evidence about effective interventions in these settings expert opinion is that a broad public policy response which addresses direct strategies for prevention, early intervention and treatment; health service and health workforce requirements; social inclusion of marginalised groups of adolescents; and specific education is required. Specific endorsed strategies include public education, parent education, training for teachers and primary healthcare workers, psycho-educational curricula, identification through periodic screening of the most vulnerable and referral for care, and the availability of counsellors or other identified trained staff members in schools from whom adolescents can seek assistance for

  16. Gas exchange and leaf anatomy of a C3-CAM hybrid, Yucca gloriosa (Asparagaceae).

    Science.gov (United States)

    Heyduk, Karolina; Burrell, Nia; Lalani, Falak; Leebens-Mack, Jim

    2016-03-01

    While the majority of plants use the typical C3 carbon metabolic pathway, ~6% of angiosperms have adapted to carbon limitation as a result of water stress by employing a modified form of photosynthesis known as Crassulacean acid metabolism (CAM). CAM plants concentrate carbon in the cells by temporally separating atmospheric carbon acquisition from fixation into carbohydrates. CAM has been studied for decades, but the evolutionary progression from C3 to CAM remains obscure. In order to better understand the morphological and physiological characteristics associated with CAM photosynthesis, phenotypic variation was assessed in Yucca aloifolia, a CAM species, Yucca filamentosa, a C3 species, and Yucca gloriosa, a hybrid species derived from these two yuccas exhibiting intermediate C3-CAM characteristics. Gas exchange, titratable leaf acidity, and leaf anatomical traits of all three species were assayed in a common garden under well-watered and drought-stressed conditions. Yucca gloriosa showed intermediate phenotypes for nearly all traits measured, including the ability to acquire carbon at night. Using the variation found among individuals of all three species, correlations between traits were assessed to better understand how leaf anatomy and CAM physiology are related. Yucca gloriosa may be constrained by a number of traits which prevent it from using CAM to as high a degree as Y. aloifolia. The intermediate nature of Y. gloriosa makes it a promising system in which to study the evolution of CAM. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  17. Carbon capture by hybrid separation processes

    NARCIS (Netherlands)

    van Benthum, R.J.; van Kemenade, H.P.; Brouwers, J.J.H.

    2014-01-01

    Even though there is an increasing development of carbon capture technology over the last decade, large-scale implementation is still far from common practice, mainly caused by the energy intensiveness of carbon capture processes and the lack of regulation. In absence of strict regulation, less

  18. Carbon-Based Materials for Lithium-Ion Batteries, Electrochemical Capacitors, and Their Hybrid Devices.

    Science.gov (United States)

    Yao, Fei; Pham, Duy Tho; Lee, Young Hee

    2015-07-20

    A rapidly developing market for portable electronic devices and hybrid electrical vehicles requires an urgent supply of mature energy-storage systems. As a result, lithium-ion batteries and electrochemical capacitors have lately attracted broad attention. Nevertheless, it is well known that both devices have their own drawbacks. With the fast development of nanoscience and nanotechnology, various structures and materials have been proposed to overcome the deficiencies of both devices to improve their electrochemical performance further. In this Review, electrochemical storage mechanisms based on carbon materials for both lithium-ion batteries and electrochemical capacitors are introduced. Non-faradic processes (electric double-layer capacitance) and faradic reactions (pseudocapacitance and intercalation) are generally explained. Electrochemical performance based on different types of electrolytes is briefly reviewed. Furthermore, impedance behavior based on Nyquist plots is discussed. We demonstrate the influence of cell conductivity, electrode/electrolyte interface, and ion diffusion on impedance performance. We illustrate that relaxation time, which is closely related to ion diffusion, can be extracted from Nyquist plots and compared between lithium-ion batteries and electrochemical capacitors. Finally, recent progress in the design of anodes for lithium-ion batteries, electrochemical capacitors, and their hybrid devices based on carbonaceous materials are reviewed. Challenges and future perspectives are further discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Supplier Selection Study under the Respective of Low-Carbon Supply Chain: A Hybrid Evaluation Model Based on FA-DEA-AHP

    Directory of Open Access Journals (Sweden)

    Xiangshuo He

    2018-02-01

    Full Text Available With the development of global environment and social economy, it is an indispensable choice for enterprises to achieve sustainable growth through developing low-carbon economy and constructing low-carbon supply chain. Supplier is the source of chain, thus selecting excellent low-carbon supplier is the foundation of establishing efficient low-carbon supply chain. This paper presents a novel hybrid model for supplier selection integrated factor analysis (FA, data envelopment analysis (DEA, with analytic hierarchy process (AHP, namely FA-DEA-AHP. First, an evaluation index system is built, incorporating product level, qualification, cooperation ability, and environmental competitiveness. FA is utilized to extract common factors from the 18 pre-selected indicators. Then, DEA is applied to establish the pairwise comparison matrix and AHP is employed to rank these low-carbon suppliers comprehensively and calculate the validity of the decision-making units. Finally, an experiment study with seven cement suppliers in a large industrial enterprise is carried out in this paper. The results reveal that the proposed technique can not only select effective suppliers, but also realize a comprehensive ranking. This research has enriched the methodology of low-carbon supplier evaluation and selection, as well as owns theoretical value in exploring the coordinated development of low-carbon supply chain to some extent.

  20. Complex Hybrid Inflation and Baryogenesis

    International Nuclear Information System (INIS)

    Delepine, David; Martinez, Carlos; Urena-Lopez, L. Arturo

    2007-01-01

    We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated with the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vacuum expectation value of the waterfall field, which is well constrained by diverse cosmological observations

  1. Complex hybrid inflation and baryogenesis.

    Science.gov (United States)

    Delepine, David; Martínez, Carlos; Ureña-López, L Arturo

    2007-04-20

    We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated with the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vacuum expectation value of the waterfall field, which is well constrained by diverse cosmological observations.

  2. Multidimensional MnO2 nanohair-decorated hybrid multichannel carbon nanofiber as an electrode material for high-performance supercapacitors

    Science.gov (United States)

    Jun, Jaemoon; Lee, Jun Seop; Shin, Dong Hoon; Kim, Sung Gun; Jang, Jyongsik

    2015-09-01

    One-dimensional (1D)-structured nanomaterials represent one of the most attractive candidates for energy-storage systems due to their contribution to design simplicity, fast charge-transportation network, and their allowance for more accessible ion diffusion. In particular, 1D-structured nanomaterials with a highly complex inner-pore configuration enhance functionality by taking advantage of both the hollow and 1D structures. In this study, we report a MnO2 nanohair-decorated, hybrid multichannel carbon nanofiber (Mn_MCNF) fabricated via single-nozzle co-electrospinning of two immiscible polymer solutions, followed by carbonization and redox reactions. With improved ion accessibility, the optimized Mn_MCNF sample (Mn_MCNF_60 corresponding to a reaction duration time of 60 min for optimal MnO2 nanohair growth) exhibited a high specific capacitance of 855 F g-1 and excellent cycling performance with ~87.3% capacitance retention over 5000 cycles.One-dimensional (1D)-structured nanomaterials represent one of the most attractive candidates for energy-storage systems due to their contribution to design simplicity, fast charge-transportation network, and their allowance for more accessible ion diffusion. In particular, 1D-structured nanomaterials with a highly complex inner-pore configuration enhance functionality by taking advantage of both the hollow and 1D structures. In this study, we report a MnO2 nanohair-decorated, hybrid multichannel carbon nanofiber (Mn_MCNF) fabricated via single-nozzle co-electrospinning of two immiscible polymer solutions, followed by carbonization and redox reactions. With improved ion accessibility, the optimized Mn_MCNF sample (Mn_MCNF_60 corresponding to a reaction duration time of 60 min for optimal MnO2 nanohair growth) exhibited a high specific capacitance of 855 F g-1 and excellent cycling performance with ~87.3% capacitance retention over 5000 cycles. Electronic supplementary information (ESI) available: Experimental data includes

  3. EVALUATION OF CARBON DIOXIDE CAPTURE FROM EXISTING COAL FIRED PLANTS BY HYBRID SORPTION USING SOLID SORBENTS

    Energy Technology Data Exchange (ETDEWEB)

    Benson, Steven; Browers, Bruce; Srinivasachar, Srivats; Laudal, Daniel

    2014-12-31

    Under contract DE-FE0007603, the University of North Dakota conducted the project Evaluation of Carbon Dioxide Capture from Existing Coal Fired Plants by Hybrid Sorption Using Solid Sorbents. As an important element of this effort, a Technical and Economic Feasibility Study was conducted by Barr Engineering Co. (Barr) in association with the University of North Dakota. The assessment developed a process flow diagram, major equipment list, heat balances for the SCPC power plant, capital cost estimate, operating cost estimate, levelized cost of electricity, cost of CO2 capture ($/ton) and three sensitivity cases for the CACHYS™ process.

  4. Deposition and properties of Al-containing diamond-like carbon films by a hybrid ion beam sources

    International Nuclear Information System (INIS)

    Dai Wei; Wang Aiying

    2011-01-01

    Research highlights: → Weak carbide former, Al element, was incorporated into DLC films using a hybrid ion beams system comprising an anode-layer ion source and a magnetron sputtering unit. → The structure disorder of the films tended to decrease with Al atoms doping, which resulted in the distinct reduction of the film internal stress and hardness, but the internal stress dropped faster than the hardness. → The DLC films with low internal stress and high hardness can be acquired by Al incorporation. - Abstract: Metal incorporation is one of the most effective methods for relaxing internal stress in diamond-like carbon (DLC) films. It was reported that the chemical state of the incorporated metal atoms has a significant influence on the film internal stress. The doped atoms embedding in the DLC matrix without bonding with C atoms can reduce the structure disorder of the DLC films through bond angle distortion and thus relax the internal stress of the films. In present paper, Al atoms, which are inert to carbon, were incorporated into the DLC films deposited by a hybrid ion beams system comprising an anode-layer ion source and a magnetron sputtering unit. The film composition, microstructure and atomic bond structure were characterized using X-ray photoelectron spectroscopy, transmission electron microscopy and Raman spectroscopy. The internal stress, mechanical properties and tribogoical behavior were studied as a function of Al concentration using a stress-tester, nanoindentation and ball-on-disc tribo-tester, respectively. The results indicated that the incorporated Al atoms were dissolved in the DLC matrix without bonding with C atoms and the films exhibited the feature of amorphous carbon. The structure disorder of the films tended to decrease with Al atoms incorporation. This resulted in the distinct reduction of the internal stress in the films. All Al-DLC films exhibited a lower friction coefficient compared with pure DLC film. The formation of the

  5. The effect of microstructure and texture evolution on mechanical properties of low-carbon steel processed by the continuous hybrid process

    International Nuclear Information System (INIS)

    Hwang, Sun Kwang; Baek, Hyun Moo; Son, Il-Heon; Im, Yong-Taek; Bae, Chul Min

    2013-01-01

    In this paper, the continuous hybrid process is newly designed and applied for producing grain-refined long and large cross-section wires of low-carbon steel at high speed at room temperature. The initial specimen, with a diameter of 13 mm, continuously passes through the rolls, equal channel angular pressing (ECAP) dies, and wire-drawing dies in sequence during the process. The specimens deformed by the continuous hybrid process without and with the wire-drawing dies were obtained to investigate the role in the deformation separately. Their microstructures, textures, and mechanical properties were investigated by optical microscopy (OM), electron backscattering diffraction (EBSD), X-ray diffraction (XRD), tension, and Vickers micro-hardness tests and were compared with those for the case processed by the conventional wire-drawing process. According to the present investigation, the continuous hybrid process can more efficiently manufacture fine-grained wires with a strong shear texture in a continuous way than the conventional wire-drawing process can. In addition, the ultimate tensile strength value of the specimen processed by the continuous hybrid process was 23.9% higher, although the elongation was slightly lower than the one produced by the conventional wire-drawing process. The plastic deformation was mainly imposed by the ECAP dies, and the wire-drawing dies improve the dimensional accuracy and increase the local strain homogeneity in the continuous hybrid process. It is demonstrated that the continuous hybrid process might be beneficial in commercializing a continuous application of the severe plastic deformation process for producing grain-refined wires for industrial applications

  6. In situ preparation of Fe3O4 in a carbon hybrid of graphene nanoscrolls and carbon nanotubes as high performance anode material for lithium-ion batteries

    Science.gov (United States)

    Liu, Yuewen; Hassan Siddique, Ahmad; Huang, Heran; Fang, Qile; Deng, Wei; Zhou, Xufeng; Lu, Huanming; Liu, Zhaoping

    2017-11-01

    A new conductive carbon hybrid combining both reduced graphene nanoscrolls and carbon nanotubes (rGNSs-CNTs) is prepared, and used to host Fe3O4 nanoparticles through an in situ synthesis method. As an anode material for LIBs, the obtained Fe3O4@rGNSs-CNTs shows good electrochemical performance. At a current density of 0.1 A g-1, the anode material shows a high reversible capacity of 1232.9 mAh g-1 after 100 cycles. Even at a current density of 1 A g-1, it still achieves a high reversible capacity of 812.3 mAh g-1 after 200 cycles. Comparing with bare Fe3O4 and Fe3O4/rGO composite anode materials without nanoscroll structure, Fe3O4@rGNSs-CNTs shows much better rate capability with a reversible capacity of 605.0 and 500.0 mAh g-1 at 3 and 5 A g-1, respectively. The excellent electrochemical performance of the Fe3O4@rGNSs-CNTs anode material can be ascribed to the hybrid structure of rGNSs-CNTs, and their strong interaction with Fe3O4 nanoparticles, which on one hand provides more pathways for lithium ions and electrons, on the other hand effectively relieves the volume change of Fe3O4 during the charge-discharge process.

  7. A superhard sp3 microporous carbon with direct bandgap

    Science.gov (United States)

    Pan, Yilong; Xie, Chenlong; Xiong, Mei; Ma, Mengdong; Liu, Lingyu; Li, Zihe; Zhang, Shuangshuang; Gao, Guoying; Zhao, Zhisheng; Tian, Yongjun; Xu, Bo; He, Julong

    2017-12-01

    Carbon allotropes with distinct sp, sp2, and sp3 hybridization possess various different properties. Here, a novel all-sp3 hybridized tetragonal carbon, namely the P carbon, was predicted by the evolutionary particle swarm structural search. It demonstrated a low density among all-sp3 carbons, due to the corresponding distinctive microporous structure. P carbon is thermodynamically stable than the known C60 and could be formed through the single-walled carbon nanotubes (SWCNTs) compression. P carbon is a direct bandgap semiconductor displaying a strong and superhard nature. The unique combination of electrical and mechanical properties constitutes P carbon a potential superhard material for semiconductor industrial fields.

  8. SusClime. A simulation game on population and development in a resource- and climate-constrained two-country world

    International Nuclear Information System (INIS)

    De Vries, B.

    1995-10-01

    In this report we introduce simulation-gaming as a tool to explore long-term futures. The model world of SusClime is a simple world with two capital stocks, one producing goods ('goods producing capital') and one providing services including consumption ('population capital') for the people. The necessary energy is delivered by two capital stocks, one based on oil ('carbon-energy') and one on renewable energy ('alternative'). Investments in energy efficiency bring down the required energy. The important decisions in the game are about investments, that is, the allocation of the goods produced among these five capital stocks. Moreover, the two countries can trade oil and make loans. The major challenge is to go through the demographic transition by increasing the welfare per person and to make the transition from oil to renewable energy. The latter is needed to avoid negative impacts on the economy due to rising CO 2 -concentrations. After the description of the game, some suggestions for systematic experiments are made as a way to gain a better understanding about how cultural bias affects people's perception of and behaviour with regard to aspects of the quest for sustainable development. 10 figs., 2 tabs., 36 refs., 6 appendices

  9. Design and development of low-power driven hybrid electroluminescent lamp from carbon nanotube embedded phosphor material

    International Nuclear Information System (INIS)

    Yadav, Deepika; Mishra, Savvi; Shanker, Virendra; Haranath, D.

    2013-01-01

    Highlights: •We are first to report CNT embedded ZnS:Mn hybrid EL system. •Achieved efficient orange-red EL emission at low operating voltages ( AC ). •Facile technique to induce conductive paths inside the ZnS particle to trigger EL. •Detailed electrical characterization of EL lamp is presented. -- Abstract: We present a novel methodology to design a hybrid electroluminescent (EL) lamp by embedding carbon nanotubes (CNTs) inside the ZnS:Mn phosphor particles by conventional solid state diffusion technique. By doing so, the phosphor particles exhibited increase in EL brightness and efficiency at low operating voltages ( AC ). Interestingly, shorter the length of CNTs used, greater was the field enhancement effect and lower was the operating voltages to glow the EL lamps. The role of CNTs have been identified to form conductive paths inside the ZnS particle thereby triggering EL due to electron injection to luminescent centers (Mn 2+ ) at nominal voltages. In addition, a detailed electrical characterization of the novel EL lamp along with its spectral energy distribution studies are presented

  10. Integrated fast assembly of free-standing lithium titanate/carbon nanotube/cellulose nanofiber hybrid network film as flexible paper-electrode for lithium-ion batteries.

    Science.gov (United States)

    Cao, Shaomei; Feng, Xin; Song, Yuanyuan; Xue, Xin; Liu, Hongjiang; Miao, Miao; Fang, Jianhui; Shi, Liyi

    2015-05-27

    A free-standing lithium titanate (Li4Ti5O12)/carbon nanotube/cellulose nanofiber hybrid network film is successfully assembled by using a pressure-controlled aqueous extrusion process, which is highly efficient and easily to scale up from the perspective of disposable and recyclable device production. This hybrid network film used as a lithium-ion battery (LIB) electrode has a dual-layer structure consisting of Li4Ti5O12/carbon nanotube/cellulose nanofiber composites (hereinafter referred to as LTO/CNT/CNF), and carbon nanotube/cellulose nanofiber composites (hereinafter referred to as CNT/CNF). In the heterogeneous fibrous network of the hybrid film, CNF serves simultaneously as building skeleton and a biosourced binder, which substitutes traditional toxic solvents and synthetic polymer binders. Of importance here is that the CNT/CNF layer is used as a lightweight current collector to replace traditional heavy metal foils, which therefore reduces the total mass of the electrode while keeping the same areal loading of active materials. The free-standing network film with high flexibility is easy to handle, and has extremely good conductivity, up to 15.0 S cm(-1). The flexible paper-electrode for LIBs shows very good high rate cycling performance, and the specific charge/discharge capacity values are up to 142 mAh g(-1) even at a current rate of 10 C. On the basis of the mild condition and fast assembly process, a CNF template fulfills multiple functions in the fabrication of paper-electrode for LIBs, which would offer an ever increasing potential for high energy density, low cost, and environmentally friendly flexible electronics.

  11. Rheological and electrical properties of hybrid nanocomposites of epoxy resins filled with graphite nanoplatelets and carbon black.

    Science.gov (United States)

    Truong, Quang-Trung; Lee, Seon-Suk; Lee, Dai-Soo

    2011-02-01

    Graphite nanoplatelets (GNP) were prepared by microwave irradiation of natural graphites intercalated with ferric chloride in nitromethane (GIC). Intercalated structure of GIC was confirmed by X-ray diffraction patterns. SEM images of GIC after microwave irradiation showed the exfoliation of GIC, the formation of GNPs. Hybrid nanocomposites of bisphenol-A type epoxy resins filled with GNP and a conductive carbon black (CB) were prepared and rheological and electrical properties of the nanocomposites were investigated. Viscosity and electrical surface resistivity of the nanocomposites showed minima at certain mixtures of GNP and CB in the epoxy resins.

  12. Optimal dispatch in dynamic security constrained open power market

    International Nuclear Information System (INIS)

    Singh, S.N.; David, A.K.

    2002-01-01

    Power system security is a new concern in the competitive power market operation, because the integration of the system controller and the generation owner has been broken. This paper presents an approach for dynamic security constrained optimal dispatch in restructured power market environment. The transient energy margin using transient energy function (TEF) approach has been used to calculate the stability margin of the system and a hybrid method is applied to calculate the approximate unstable equilibrium point (UEP) that is used to calculate the exact UEP and thus, the energy margin using TEF. The case study results illustrated on two systems shows that the operating mechanisms are compatible with the new business environment. (author)

  13. Preparation and toxicological assessment of functionalized carbon nanotube-polymer hybrids.

    Directory of Open Access Journals (Sweden)

    Nikos D Koromilas

    Full Text Available Novel Carbon Nanotube-Polymer Hybrids were synthesized as potential materials for the development of membranes for water treatment applications in the field of Membrane Bioreactors (MBRs. Due to the toxicological concerns regarding the use of nanomaterials in water treatment as well as the rising demand for safe drinking water to protect public health, we studied the functionalization of MWCNTs and Thin-MWCNTs as to control their properties and increase their ability of embedment into porous anisotropic polymeric membranes. Following the growth of the hydrophilic monomer on the surface of the properly functionalized CNTs, that act as initiator for the controlled radical polymerization (ATRP of sodium styrene sulfonate (SSNa, the antimicrobial quaternized phosphonium and ammonium salts were attached on CNTs-g-PSSNa through non-covalent bonding. In another approach the covalent attachment of quaternized ammonium polymeric moieties of acrylic acid-vinyl benzyl chloride copolymers with N,N-dimethylhexadecylamine (P(AA12-co-VBCHAM on functionalized CNTs has also been attempted. Finally, the toxicological assessment in terms of cell viability and cell morphological changes revealed that surface characteristics play a major role in the biological response of functionalized CNTs.

  14. Hyaluronan and calcium carbonate hybrid nanoparticles for colorectal cancer chemotherapy

    Science.gov (United States)

    Bai, Jinghui; Xu, Jian; Zhao, Jian; Zhang, Rui

    2017-09-01

    A hybrid drug delivery system (DDS) composed of hyaluronan and calcium carbonate (CC) was developed. By taking advantage of the tumor-targeting ability of hyaluronan and the drug-loading property of CC, the well-formed hyaluronan-CC nanoparticles were able to serve as a DDS targeting colorectal cancer with a decent drug loading content, which is beneficial in the chemotherapy of colorectal cancer. In this study, hyaluronan-CC nanoparticles smaller than 100 nm were successfully developed to load the wide-range anti-cancer drug adriamycin (Adr) to construct hyaluronan-CC/Adr nanoparticles. On the other hand, we also found that hyaluronan-CC/Adr nanoparticles can possibly increase the uptake ratio of Adr into HT29 colorectal cancer cells when compared with hyaluronan-free nanoparticles (CC/Adr) via the CD44 receptor-mediated endocytosis via competitive uptake and in vivo imaging assays. Note that both in vitro (CCK-8 assay on HT29 cells) and in vivo (anti-cancer assay on HT-29 tumor-bearing nude mice model) experiments revealed that hyaluronan-CC/Adr nanoparticles exhibited stronger anti-cancer activity than free Adr or CC/Adr nanoparticles with minimized toxic side effects and preferable cancer-suppression potential.

  15. Hybrid capacitor with activated carbon electrode, Ni(OH) 2 electrode and polymer hydrogel electrolyte

    Science.gov (United States)

    Nohara, Shinji; Asahina, Toshihide; Wada, Hajime; Furukawa, Naoji; Inoue, Hiroshi; Sugoh, Nozomu; Iwasaki, Hideharu; Iwakura, Chiaki

    A new hybrid capacitor (HC) cell was assembled using an activated carbon (AC) negative electrode, an Ni(OH) 2 positive electrode and a polymer hydrogel electrolyte prepared from crosslinked potassium poly(acrylate) (PAAK) and KOH aqueous solution. The HC cell was characterized compared with an electric double layer capacitor (EDLC) using two AC electrodes and the polymer hydrogel electrolyte. It was found that the HC cell successfully worked in the larger voltage range and exhibited ca. 2.4 times higher capacitance than the EDLC cell. High-rate dischargeability of the HC cell was also superior to that of the EDLC cell. These improved characteristics strongly suggest that the HC cell can be a promising system of capacitors with high energy and power densities.

  16. A fusion of top-down and bottom-up modeling techniques to constrain regional scale carbon budgets

    Science.gov (United States)

    Goeckede, M.; Turner, D. P.; Michalak, A. M.; Vickers, D.; Law, B. E.

    2009-12-01

    The effort to constrain regional scale carbon budgets benefits from assimilating as many high quality data sources as possible in order to reduce uncertainties. Two of the most common approaches used in this field, bottom-up and top-down techniques, both have their strengths and weaknesses, and partly build on very different sources of information to train, drive, and validate the models. Within the context of the ORCA2 project, we follow both bottom-up and top-down modeling strategies with the ultimate objective of reconciling their surface flux estimates. The ORCA2 top-down component builds on a coupled WRF-STILT transport module that resolves the footprint function of a CO2 concentration measurement in high temporal and spatial resolution. Datasets involved in the current setup comprise GDAS meteorology, remote sensing products, VULCAN fossil fuel inventories, boundary conditions from CarbonTracker, and high-accuracy time series of atmospheric CO2 concentrations. Surface fluxes of CO2 are normally provided through a simple diagnostic model which is optimized against atmospheric observations. For the present study, we replaced the simple model with fluxes generated by an advanced bottom-up process model, Biome-BGC, which uses state-of-the-art algorithms to resolve plant-physiological processes, and 'grow' a biosphere based on biogeochemical conditions and climate history. This approach provides a more realistic description of biomass and nutrient pools than is the case for the simple model. The process model ingests various remote sensing data sources as well as high-resolution reanalysis meteorology, and can be trained against biometric inventories and eddy-covariance data. Linking the bottom-up flux fields to the atmospheric CO2 concentrations through the transport module allows evaluating the spatial representativeness of the BGC flux fields, and in that way assimilates more of the available information than either of the individual modeling techniques alone

  17. Gas turbine requirements for a carbon constrained environment

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.M.; Lacy, B.P.; Yilmaz, E.; (and others) [GE Energy, Schenectady, NY (United States)

    2006-07-01

    With carbon capture, the pre-combustion decarbonization of natural gas, or syngas derived from coal gasification results in gas turbines fuels that consist of 90% or higher hydrogen content. This paper discusses the challenge of low CO{sub 2} processes for advanced gas turbines with particular focus on high hydrogen combustion. 4 refs., 13 figs.

  18. Real-world fuel economy and CO{sub 2} emissions of plug-in hybrid electric vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Ploetz, Patrick; Funke, Simon Arpad; Jochem, Patrick [Fraunhofer-Institut fuer System- und Innovationsforschung (ISI), Karlsruhe (Germany). Competence Center Energiepolitik und Energiesysteme

    2015-07-01

    Plug-in hybrid electric vehicles (PHEV) combine electric propulsion with an internal combustion engine. Their potential to reduce transport related green-house gas emissions highly depends on their actual usage and electricity provision. Various studies underline their environmental and economic advantages, but are based on standardised driving cycles, simulations or small PHEV fleets. Here, we analyse real-world fuel economy of PHEV and the factors influencing it based on about 2,000 actual PHEV that have been observed over more than a year in the U.S. and Germany. We find that real-world fuel economy of PHEV differ widely among users. The main factors explaining this variation are the annual mileage, the regularity of daily driving, and the likelihood of long-distance trips. Current test cycle fuel economy ratings neglect these factors. Despite the broad range of PHEV fuel economies, the test cycle fuel economy ratings can be close to empiric PHEV fleet averages if the average annual mile-age is about 17,000 km. For the largest group of PHEV in our data, the Chevrolet Volt, we find the average fuel economy to be 1.45 litres/100 km at an average electric driving share of 78%. The resulting real-world tank-to-wheel CO{sub 2} emissions of these PHEV are 42 gCO{sub 2}/km and the annual CO{sub 2} savings in the U.S. amount to about 50 Mt. In conclusion, the variance of empirical PHEV fuel economy is considerably higher than of conventional vehicles. This should be taken into account by future test cycles and high electric driving shares should be incentivised.

  19. The Dead Speak: A Case Study from the Tiwa Tribe Highlighting the Hybrid World of Śākta Tantra in Assam

    Directory of Open Access Journals (Sweden)

    Sravana Borkataky-Varma

    2017-10-01

    Full Text Available In this paper, we shall examine how possession is understood in Assam, India. We are aware that the larger northeastern frontier of India retained indigenous practices, religious festivals, and beliefs in a plethora of exotic goddesses, rituals, which have continued unabated through modern times. This has resulted in cross-pollination between the Vedic or traditional Brahmanical or orthodox Hindu practices and the indigenous practices, which in turn has yielded a hybrid world of Śākta Tantra rituals and practices.

  20. Simulation and Optimization of One Live Pig Low-Carbon Industry Chain Using SD-RCCM

    Directory of Open Access Journals (Sweden)

    Jiuping Xu

    2013-01-01

    Full Text Available The destruction of the natural environment has been drawing more and more attention. Developing low-carbon industry chains is an effective solution to the conflict between rapid economic growth and high CO2 emissions. Summarizing various traditional and new industry chain sustainable development, live pig industry was chosen as a typical industry chain to study low-carbon development using a system dynamics and random chance-constrained model (SD-RCCM. Leshan, a world natural and cultural heritage area in China, was selected as a typical city to analyze the low-carbon pig industry. Three different programs based on distribution ratios were selected to study this industry. The results showed that program 1, which considers both environmental and economic benefits, realizes sustainable development. In order to extend the pig industry chain and fully utilize pig ordure and other waste, introducing a Clean Development Mechanism (CDM and household biogas exploitation program is recommended.

  1. Dynamical Baryogenesis in Complex Hybrid Inflation

    International Nuclear Information System (INIS)

    Delepine, David; Martinez, Carlos; Urena-Lopez, L. Arturo

    2008-01-01

    We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U (1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and imaginary parts of the complex field during the phase transition at the end of inflation translates into a charge asymmetry. The latter strongly depends on the vev of the waterfall field, which is well constrained by diverse cosmological observations

  2. Hybrid Arrangements as a Form of Ecological Modernization: The Case of the US Energy Efficiency Conservation Block Grants

    Directory of Open Access Journals (Sweden)

    Anya M. Galli

    2016-01-01

    Full Text Available How are environmental policy goals implemented and sustained in the context of political stagnation surrounding national climate policies in the United States? In this paper, we discuss Ecological Modernization Theory as a tool for understanding the complexity of climate governance at the sub-national level. In particular, we explore the emergence of hybrid governance arrangements during the local implementation of federal energy efficiency programs in US cities. We analyze the formation and advancement of programs associated with one effort to establish a sub-national low carbon energy policy: the Energy Efficiency and Conservation Block Grant (EECBG program administered by the US Department of Energy. Our findings highlight the diverse range of partnerships between state, private, and civil society actors that emerged through this program and point to some of the challenges associated with collaborative climate governance initiatives at the city level. Although some programs reflected ecologically modern outcomes, other cities were constrained in their ability to move beyond the status quo due to the demands of state bureaucracies and the challenges associated with inconsistent funding. We find that these programs cultivated hybrid arrangements in an effort to sustain the projects following the termination of federal grant funding. Overall, hybrid governance plays an important role in the implementation and long-term sustainability of climate-related policies.

  3. Laser driven fusion fission hybrids

    International Nuclear Information System (INIS)

    Hansen, L.F.; Maniscalco, J.A.

    1977-11-01

    The role of the fusion-fission hybrid reactor (FFHR) as a fissile fuel and/or power producer is discussed. As long range options to supply the world energy needs, hybrid-fueled thermal-burner reactors are compared to liquid metal fast breeder reactors (LMFBR). A discussion of different fuel cycles (thorium, depleted uranium, and spent fuel) is presented in order to compare the energy multiplication, the production of fissile fuel, the laser efficiency and pellet gain requirements of the hybrid reactor. Lawrence Livermore Laboratory (LLL) has collaborated with Bechtel Corporation and with Westinghouse in two engineering design studies of laser fusion driven hybrid power plants. The hybrid designs which have resulted from these two studies are briefly described and analyzed by considering operational parameters, such as energy multiplication, power density, burn-up and plutonium production as a function time

  4. Hybrid War and Its Strategic Implications to Turkey

    OpenAIRE

    Bingöl, Oktay

    2017-01-01

    Discussions on the hybrid threats and hybrid wars have begun to gain interest among the securitycommunities around the world since 2000s, and exponentially increased after Russian-Ukraine conflict in 2014. The political and military conflict between Russia and Turkey sinceNovember 2015 has carried the discussion to Turkey. Now it is believed that Turkey is infact in a multi-front hybrid war with some of its neighbors but not just Russia. In this articleit is aimed to fully explore hybrid war ...

  5. Effect of reduced graphene oxide-carbon nanotubes hybrid nanofillers in mechanical properties of polymer nanocomposites

    Science.gov (United States)

    Sa, Kadambinee; Mahakul, Prakash C.; Subramanyam, B. V. R. S.; Raiguru, Jagatpati; Das, Sonali; Alam, Injamul; Mahanandia, Pitamber

    2018-03-01

    Graphene and carbon nanotubes (CNTs) have tremendous interest as reinforcing fillers due to their excellent physical properties. However, their reinforcing effect in polymer matrix is limited due to agglomeration of graphene and CNTs within the polymer matrix. Mechanical properties by the admixture of reduced graphene oxide (rGO) and CNTs in Poly (methyl methacrylate) (PMMA) prepared by solution mixing method has been investigated. The prepared samples are characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy. The hybrid composite shows improvement in the mechanical properties compared to rGO/PMMA and MWCNTs/PMMA composites due to better interaction between rGO-MWCNTs and polymer matrix.

  6. Reactive microencapsulation of carbon allotropes in polyamide shell-core structures and their transformation in hybrid composites with tailored electrical properties

    Directory of Open Access Journals (Sweden)

    F. Oliveira

    2016-02-01

    Full Text Available Polyamide 6 microcapsules (PAMC loaded with 2–10 wt% of different carbon allotropes: carbon black, multiwalled carbon nanotubes, carbon nanofibers and graphite were synthesized via activated anionic polymerization (AAROP of ε-caprolactam in solution performed in the presence of the respective micro- or nanosized loads. The forming high-molecular weight microporous PAMC showed typical diameters of 15–35 µm, the filler particles being entrapped in the core as proven by microscopy methods. The melt processing of the loaded microcapsules produced PA6/C-filler hybrid thermoplastic composites with homogeneous distribution of one or two C-fillers even at loads of up to 10% without any functionalization. The crystalline structure of all PAMC and molded composites was studied by thermal and X-ray diffraction methods focusing on possible structure modification during the transition from PAMC to molded plates. Mechanical tests in tension and electrical conductivity measurements showed that transforming loaded PAMC into composites by melt processing could be a facile and rapid method to fabricate polyamide composites with improved mechanical performance and tailored electrical and dielectric properties.

  7. Functionalized carbon nanotube based hybrid electrochemical capacitors using neutral bromide redox-active electrolyte for enhancing energy density

    Science.gov (United States)

    Tang, Xiaohui; Lui, Yu Hui; Chen, Bolin; Hu, Shan

    2017-06-01

    A hybrid electrochemical capacitor (EC) with enhanced energy density is realized by integrating functionalized carbon nanotube (FCNT) electrodes with redox-active electrolyte that has a neutral pH value (1 M Na2SO4 and 0.5 M KBr mixed aqueous solution). The negative electrode shows an electric double layer capacitor-type behavior. On the positive electrode, highly reversible Br-/Br3- redox reactions take place, presenting a battery-type behavior, which contributes to increase the capacitance of the hybrid cell. The voltage window of the whole cell is extended up to 1.5 V because of the high over-potentials of oxygen and hydrogen evolution reactions in the neutral electrolyte. Compared with raw CNT, the FCNT has better wettability in the aqueous electrolyte and contributes to increase the electric double layer capacitance of the cell. As a result, the maximum energy density of 28.3 Wh kg-1 is obtained from the hybrid EC at 0.5 A g-1 without sacrificing its power density, which is around 4 times larger than that of the electrical double layer capacitor constructed by FCNT electrodes and 1 M Na2SO4 electrolyte. Moreover, the discharge capacity retained 86.3% of its initial performance after 10000 cycles of galvanostatic charge and discharge test (10 A/g), suggesting its long life cycle even at high current loading.

  8. Palygorskite Hybridized Carbon Nanocomposite as a High ...

    African Journals Online (AJOL)

    NICO

    Pd nanoparticles were deposited on the hybrid support as an electrocatalyst for formic acid oxida- tion. .... synthetic procedure using conventional borohydride reduction .... as Al2O3, CaO and MgO, which may exist in both the tetrahedral.

  9. Real world CO2 and NOx emissions from 149 Euro 5 and 6 diesel, gasoline and hybrid passenger cars.

    Science.gov (United States)

    O'Driscoll, Rosalind; Stettler, Marc E J; Molden, Nick; Oxley, Tim; ApSimon, Helen M

    2018-04-15

    In this study CO 2 and NO x emissions from 149 Euro 5 and 6 diesel, gasoline and hybrid passenger cars were compared using a Portable Emissions Measurement System (PEMS). The models sampled accounted for 56% of all passenger cars sold in Europe in 2016. We found gasoline vehicles had CO 2 emissions 13-66% higher than diesel. During urban driving, the average CO 2 emission factor was 210.5 (sd. 47) gkm -1 for gasoline and 170.2 (sd. 34) gkm -1 for diesel. Half the gasoline vehicles tested were Gasoline Direct Injection (GDI). Euro 6 GDI engines cars. The average urban NO x emission from Euro 6 diesel vehicles 0.44 (sd. 0.44) gkm -1 was 11 times higher than for gasoline 0.04 (sd. 0.04) gkm -1 . We also analysed two gasoline-electric hybrids which out-performed both gasoline and diesel for NO x and CO 2 . We conclude action is required to mitigate the public health risk created by excessive NO x emissions from modern diesel vehicles. Replacing diesel with gasoline would incur a substantial CO 2 penalty, however greater uptake of hybrid vehicles would likely reduce both CO 2 and NO x emissions. Discrimination of vehicles on the basis of Euro standard is arbitrary and incentives should promote vehicles with the lowest real-world emissions of both NO x and CO 2 . Copyright © 2017 Elsevier B.V. All rights reserved.

  10. The Electrochemical Characteristics of Hybrid Capacitor Prepared by Chemical Activation of NaOH

    International Nuclear Information System (INIS)

    Choi, Jeong Eun; Bae, Ga Yeong; Yang, Jeong Min; Lee, Jong Dae

    2013-01-01

    Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481m 2 /g) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using LiMn 2 O 4 , LiCoO 2 as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes (LiPF 6 , TEABF 4 ) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using LiMn 2 O 4 /AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg

  11. Conductive Carbon Coatings for Electrode Materials

    International Nuclear Information System (INIS)

    Doeff, Marca M.; Kostecki, Robert; Wilcox, James; Lau, Grace

    2007-01-01

    A simple method for optimizing the carbon coatings on non-conductive battery cathode material powders has been developed at Lawrence Berkeley National Laboratory. The enhancement of the electronic conductivity of carbon coating enables minimization of the amount of carbon in the composites, allowing improvements in battery rate capability without compromising energy density. The invention is applicable to LiFePO 4 and other cathode materials used in lithium ion or lithium metal batteries for high power applications such as power tools and hybrid or plug-in hybrid electric vehicles. The market for lithium ion batteries in consumer applications is currently $5 billion/year. Additionally, lithium ion battery sales for vehicular applications are projected to capture 5% of the hybrid and electric vehicle market by 2010, and 36% by 2015 (http://www.greencarcongress.com). LiFePO 4 suffers from low intrinsic rate capability, which has been ascribed to the low electronic conductivity (10 -9 S cm -1 ). One of the most promising approaches to overcome this problem is the addition of conductive carbon. Co-synthesis methods are generally the most practical route for carbon coating particles. At the relatively low temperatures ( 4 , however, only poorly conductive disordered carbons are produced from organic precursors. Thus, the carbon content has to be high to produce the desired enhancement in rate capability, which decreases the cathode energy density

  12. Carbon-Based Fibrous EDLC Capacitors and Supercapacitors

    Directory of Open Access Journals (Sweden)

    C. Lekakou

    2011-01-01

    Full Text Available This paper investigates electrochemical double-layer capacitors (EDLCs including two alternative types of carbon-based fibrous electrodes, a carbon fibre woven fabric (CWF and a multiwall carbon nanotube (CNT electrode, as well as hybrid CWF-CNT electrodes. Two types of separator membranes were also considered. An organic gel electrolyte PEO-LiCIO4-EC-THF was used to maintain a high working voltage. The capacitor cells were tested in cyclic voltammetry, charge-discharge, and impedance tests. The best separator was a glass fibre-fine pore filter. The carbon woven fabric electrode and the corresponding supercapacitor exhibited superior performance per unit area, whereas the multiwall carbon nanotube electrode and corresponding supercapacitor demonstrated excellent specific properties. The hybrid CWF-CNT electrodes did not show a combined improved performance due to the lack of carbon nanotube penetration into the carbon fibre fabric.

  13. Carbon Supported Engineering NiCo2O4 Hybrid Nanofibers with Enhanced Electrocatalytic Activity for Oxygen Reduction Reaction

    Directory of Open Access Journals (Sweden)

    Diab Hassan

    2016-09-01

    Full Text Available The design of cheap and efficient oxygen reduction reaction (ORR electrocatalysts is of a significant importance in sustainable and renewable energy technologies. Therefore, ORR catalysts with superb electrocatalytic activity and durability are becoming a necessity but still remain challenging. Herein, we report C/NiCo2O4 nanocomposite fibers fabricated by a straightforward electrospinning technique followed by a simple sintering process as a promising ORR electrocatalyst in alkaline condition. The mixed-valence oxide can offer numerous accessible active sites. In addition, the as-obtained C/NiCo2O4 hybrid reveals significantly remarkable electrocatalytic performance with a highly positive onset potential of 0.65 V, which is only 50 mV lower than that of commercially available Pt/C catalysts. The analyses indicate that C/NiCo2O4 catalyst can catalyze O2-molecules via direct four electron pathway in a similar behavior as commercial Pt/C catalysts dose. Compared to single NiCo2O4 and carbon free NiCo2O4, the C/NiCo2O4 hybrid displays higher ORR current and more positive half-wave potential. The incorporated carbon matrices are beneficial for fast electron transfer and can significantly impose an outstanding contribution to the electrocatalytic activity. Results indicate that the synthetic strategy hold a potential as efficient route to fabricate highly active nanostructures for practical use in energy technologies.

  14. World nuclear performance report 2016. A new study by World Nuclear Association

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, Jonathan [World Nuclear Association, London (United Kingdom)

    2016-08-15

    A larger number of nuclear power units are under construction than at any other time in the last 25 years, and with another ten new reactors coming online 2015 demonstrated improving new build performance all round. The existing global fleet, totally 439 by year-end, generated roughly 10 % of the world's electricity, making up around one-third of the world's low-carbon electricity supply. Nevertheless, there are challenges ahead for the global nuclear industry. The World Nuclear Association's vision for the future global electricity system consists of a diverse mix of low-carbon technologies - where renewables, nuclear and a fossil fuels work together in harmony to ensure a reliable, affordable and clean energy supply.

  15. World nuclear performance report 2016. A new study by World Nuclear Association

    International Nuclear Information System (INIS)

    Cobb, Jonathan

    2016-01-01

    A larger number of nuclear power units are under construction than at any other time in the last 25 years, and with another ten new reactors coming online 2015 demonstrated improving new build performance all round. The existing global fleet, totally 439 by year-end, generated roughly 10 % of the world's electricity, making up around one-third of the world's low-carbon electricity supply. Nevertheless, there are challenges ahead for the global nuclear industry. The World Nuclear Association's vision for the future global electricity system consists of a diverse mix of low-carbon technologies - where renewables, nuclear and a fossil fuels work together in harmony to ensure a reliable, affordable and clean energy supply.

  16. The convenient truth LPG: clean energy for a low carbon world

    International Nuclear Information System (INIS)

    Rolland, M.

    2008-01-01

    deforestation thus preserving the trees needed to maintain a global climatic equilibrium and combat climate change. When implementing climate change policies, every ton of GHG reduction helps, especially in the context of emissions trading. LP Gas offers a tremendous opportunity for a range of industries to meet or exceed their legislative requirements on GHG emissions, and it is widely available today. Policy-makers should consider LP gas when seeking a switch from business-as-usual energy solutions. The European Union (EU) is taking a world leadership towards sustainable (World Energy Technology Outlook), a 'Carbon Constraint Case' can lead to a future win-win solution: a strong reduction of CO 2 emissions and the emergence of new and clean energy technologies. The way towards a post-carbon society is challenging. Technological developments are necessary but not sufficient. Socio-economic actions, market instruments and land use measures should also help to make the difference. (author)

  17. Biological Hydrogen Carriers: Harnessing Fossil Fuels in a Carbon-Constrained World

    Directory of Open Access Journals (Sweden)

    Mark T. Holtzapple

    2009-05-01

    Full Text Available Due to their widespread availability, the use of lignocellulosic resources as feedstocks for fuels and chemicals is very promising. To make this a practical reality, 18 years of research at Texas A&M University have resulted in the development of a novel process known as MixAlco.TM This article compares this process with other technologies and provides some process details. At the end, a brief economic analysis is presented. / Debido a una amplia disponibilidad, el uso de recursos lignocelulósicos como materia prima para producir combustibles y otros productos químicos es muy prometedor. Para hacer de esto una realidad, 18 años de investigación en la Universidad de Texas A&M han resultado en el desarrollo de un proceso novedoso denominado MixAlco.TM Este artículo compara este proceso con otras tecnologías y provee algunos detalles del proceso. Por último, se presenta un breve análisis económico.

  18. Carbon nanotube-based ethanol sensors

    International Nuclear Information System (INIS)

    Brahim, Sean; Colbern, Steve; Gump, Robert; Moser, Alex; Grigorian, Leonid

    2009-01-01

    Sensors containing metal-carbon nanotube (CNT) hybrid materials as the active sensing layer were demonstrated for ethanol vapor detection at room temperature. The metal-CNT hybrid materials were synthesized by infiltrating single wall carbon nanotubes (SWNTs) with the transition metals Ti, Mn, Fe, Co, Ni, Pd or Pt. Each sensor was prepared by drop-casting dilute dispersions of a metal-CNT hybrid onto quartz substrate electrodes and the impedimetric responses to varying ethanol concentration were recorded. Upon exposure to ethanol vapor, the ac impedance (Z') of the sensors was found to decrease to different extents. The sensor containing pristine CNT material was virtually non-responsive at low ethanol concentrations (<50 ppm). In contrast, all metal-CNT hybrid sensors showed extremely high sensitivity to trace ethanol levels with 100-fold or more gains in sensitivity relative to the starting SWNT sensor. All hybrid sensors, with the exception of Ni filled CNT, exhibited significantly larger sensor responses to ethanol vapor up to 250 ppm compared to the starting SWNT sensor.

  19. Solving Optimal Control Problem of Monodomain Model Using Hybrid Conjugate Gradient Methods

    Directory of Open Access Journals (Sweden)

    Kin Wei Ng

    2012-01-01

    Full Text Available We present the numerical solutions for the PDE-constrained optimization problem arising in cardiac electrophysiology, that is, the optimal control problem of monodomain model. The optimal control problem of monodomain model is a nonlinear optimization problem that is constrained by the monodomain model. The monodomain model consists of a parabolic partial differential equation coupled to a system of nonlinear ordinary differential equations, which has been widely used for simulating cardiac electrical activity. Our control objective is to dampen the excitation wavefront using optimal applied extracellular current. Two hybrid conjugate gradient methods are employed for computing the optimal applied extracellular current, namely, the Hestenes-Stiefel-Dai-Yuan (HS-DY method and the Liu-Storey-Conjugate-Descent (LS-CD method. Our experiment results show that the excitation wavefronts are successfully dampened out when these methods are used. Our experiment results also show that the hybrid conjugate gradient methods are superior to the classical conjugate gradient methods when Armijo line search is used.

  20. Carbon footprint of premium quality export bananas: case study in Ecuador, the world's largest exporter.

    Science.gov (United States)

    Iriarte, Alfredo; Almeida, Maria Gabriela; Villalobos, Pablo

    2014-02-15

    Nowadays, the new international market demands challenge the food producing countries to include the measurement of the environmental impact generated along the production process for their products. In order to comply with the environmentally responsible market requests the measurement of the greenhouse gas emissions of Ecuadorian agricultural goods has been promoted employing the carbon footprint concept. Ecuador is the largest exporter of bananas in the world. Within this context, this study is a first assessment of the carbon footprint of the Ecuadorian premium export banana (Musa AAA) using a considerable amount of field data. The system boundaries considered from agricultural production to delivery in a European destination port. The data collected over three years permitted identifying the hot spot stages. For the calculation, the CCaLC V3.0 software developed by the University of Manchester is used. The carbon footprint of the Ecuadorian export banana ranged from 0.45 to 1.04 kg CO2-equivalent/kg banana depending on the international overseas transport employed. The principal contributors to the carbon footprint are the on farm production and overseas transport stages. Mitigation and reduction strategies were suggested for the main emission sources in order to achieve sustainable banana production. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Visible light photoreactivity from hybridization states between carbon nitride bandgap states and valence states in Nb and Ti oxides

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hosik, E-mail: hosiklee@gmail.com [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology (UNIST), Unist-gil 100 Eonyang-eup, Ulsan 689-798 (Korea, Republic of); Ohno, Takahisa, E-mail: OHNO.Takahisa@nims.go.jp [Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Material Science, 1-2-1 Sengen, Tsukuba (Japan); Computational Materials Science Unit (CMSU), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047 (Japan)

    2013-03-29

    Highlights: ► Origin of bandgap reduction for visible photoreactivity is suggested. ► Carbon nitride adsorption in interlayer space can induce the bandgap reduction. ► The electronic structures are studied by density functional theory calculations. - Abstract: For better efficiency as photocatalysts, N-doping for visible light reactivity has been intensively studied in Lamellar niobic and titanic solid acids (HNb{sub 3}O{sub 8}, H{sub 2}Ti{sub 4}O{sub 9}), and its microscopic structures have been debated in this decade. We calculate the layered solid acids’ structures and bandgaps. Bandgap reduction by carbon nitride adsorption in interlayer space is observed computationally. It originates from localized nitrogen states which form delocalized top-valence states by hybridizing with the host oxygen states and can contribute to photo-current.

  2. Carbon balance of China constrained by CONTRAIL aircraft CO2 measurements

    Science.gov (United States)

    Jiang, F.; Wang, H. M.; Chen, J. M.; Machida, T.; Zhou, L. X.; Ju, W. M.; Matsueda, H.; Sawa, Y.

    2014-09-01

    Terrestrial carbon dioxide (CO2) flux estimates in China using atmospheric inversion method are beset with considerable uncertainties because very few atmospheric CO2 concentration measurements are available. In order to improve these estimates, nested atmospheric CO2 inversion during 2002-2008 is performed in this study using passenger aircraft-based CO2 measurements over Eurasia from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project. The inversion system includes 43 regions with a focus on China, and is based on the Bayesian synthesis approach and the TM5 transport model. The terrestrial ecosystem carbon flux modeled by the Boreal Ecosystems Productivity Simulator (BEPS) model and the ocean exchange simulated by the OPA-PISCES-T model are considered as the prior fluxes. The impacts of CONTRAIL CO2 data on inverted China terrestrial carbon fluxes are quantified, the improvement of the inverted fluxes after adding CONTRAIL CO2 data are rationed against climate factors and evaluated by comparing the simulated atmospheric CO2 concentrations with three independent surface CO2 measurements in China. Results show that with the addition of CONTRAIL CO2 data, the inverted carbon sink in China increases while those in South and Southeast Asia decrease. Meanwhile, the posterior uncertainties over these regions are all reduced (2-12%). CONTRAIL CO2 data also have a large effect on the inter-annual variation of carbon sinks in China, leading to a better correlation between the carbon sink and the annual mean climate factors. Evaluations against the CO2 measurements at three sites in China also show that the CONTRAIL CO2 measurements may have improved the inversion results.

  3. Electromechanical Behavior of Chemically Reduced Graphene Oxide and Multi-walled Carbon Nanotube Hybrid Material

    Science.gov (United States)

    Benchirouf, Abderrahmane; Müller, Christian; Kanoun, Olfa

    2016-01-01

    In this paper, we propose strain-sensitive thin films based on chemically reduced graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) without adding any further surfactants. In spite of the insulating properties of the thin-film-based GO due to the presence functional groups such as hydroxyl, epoxy, and carbonyl groups in its atomic structure, a significant enhancement of the film conductivity was reached by chemical reduction with hydro-iodic acid. By optimizing the MWCNT content, a significant improvement of electrical and mechanical thin film sensitivity is realized. The optical properties and the morphology of the prepared thin films were studied using ultraviolet-visible spectroscopy (UV-Vis) and scanning electron microscope (SEM). The UV-Vis spectra showed the ability to tune the band gap of the GO by changing the MWCNT content, whereas the SEM indicated that the MWCNTs were well dissolved and coated by the GO. Investigations of the piezoresistive properties of the hybrid nanocomposite material under mechanical load show a linear trend between the electrical resistance and the applied strain. A relatively high gauge factor of 8.5 is reached compared to the commercial metallic strain gauges. The self-assembled hybrid films exhibit outstanding properties in electric conductivity, mechanical strength, and strain sensitivity, which provide a high potential for use in strain-sensing applications.

  4. Synthesis of SnO{sub 2}-activated carbon fiber hybrid catalyst for the removal of methyl violet from water

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jia, E-mail: mse_lij@ujn.edu.cn [School of Material Science and Engineering, University of Jinan, Jinan 250022 (China); Ng, Dickon H.L. [Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong (China); Song, Peng; Kong, Chao; Song, Yi [School of Material Science and Engineering, University of Jinan, Jinan 250022 (China)

    2015-04-15

    Graphical abstract: - Highlights: • A new biomass route for the synthesis of SnO{sub 2}/ACF hybrid catalyst was proposed. • The original fibrous structure of kapok fiber was retained in the SnO{sub 2}/ACF hybrid catalyst. • SnO{sub 2}/ACF hybrid catalyst exhibited high BET surface area (647–897 m{sup 2}/g) and large pore volume (0.36–0.56 cm{sup 3} g{sup −1}). • High microwave-induced catalytic activity for methyl violet degradation was obtained. - Abstract: SnO{sub 2}/activated carbon fiber (ACF) hybrid catalyst was synthesized from kapok precursor via a two-step process involving pore-fabricating and self-assembly of SnO{sub 2} nanoparticles. The morphology and phase structure of the obtained samples were characterized by X-ray diffraction, field emission scanning electron microscope, high resolution transmission electron microscopy and N{sub 2} adsorption-desorption isotherm. These results demonstrated that the synthesized SnO{sub 2}/ACF retained the hollow-fiber structure of kapok fibers. SnO{sub 2} nanoparticles dispersed uniformly over the ACF support. The obtained hybrid catalyst showed porous structure with high surface area (647–897 m{sup 2}/g) and large pore volume (0.36–0.56 cm{sup 3} g{sup −1}). In addition, the catalytic activities of the obtained samples for methyl violet degradation under microwave irradiation were also evaluated. It was found that the SnO{sub 2}/ACF catalyst exhibited high catalytic activity for methyl violet degradation due to the synergistic effect of microwave and SnO{sub 2}/ACF catalyst.

  5. Nitrous Oxide/Paraffin Hybrid Rocket Engines

    Science.gov (United States)

    Zubrin, Robert; Snyder, Gary

    2010-01-01

    Nitrous oxide/paraffin (N2OP) hybrid rocket engines have been invented as alternatives to other rocket engines especially those that burn granular, rubbery solid fuels consisting largely of hydroxyl- terminated polybutadiene (HTPB). Originally intended for use in launching spacecraft, these engines would also be suitable for terrestrial use in rocket-assisted takeoff of small airplanes. The main novel features of these engines are (1) the use of reinforced paraffin as the fuel and (2) the use of nitrous oxide as the oxidizer. Hybrid (solid-fuel/fluid-oxidizer) rocket engines offer advantages of safety and simplicity over fluid-bipropellant (fluid-fuel/fluid-oxidizer) rocket en - gines, but the thrusts of HTPB-based hybrid rocket engines are limited by the low regression rates of the fuel grains. Paraffin used as a solid fuel has a regression rate about 4 times that of HTPB, but pure paraffin fuel grains soften when heated; hence, paraffin fuel grains can, potentially, slump during firing. In a hybrid engine of the present type, the paraffin is molded into a 3-volume-percent graphite sponge or similar carbon matrix, which supports the paraffin against slumping during firing. In addition, because the carbon matrix material burns along with the paraffin, engine performance is not appreciably degraded by use of the matrix.

  6. Multi-Sensor Constrained Time Varying Emissions Estimation of Black Carbon: Attributing Urban and Fire Sources Globally

    Science.gov (United States)

    Cohen, J. B.

    2015-12-01

    The short lifetime and heterogeneous distribution of Black Carbon (BC) in the atmosphere leads to complex impacts on radiative forcing, climate, and health, and complicates analysis of its atmospheric processing and emissions. Two recent papers have estimated the global and regional emissions of BC using advanced statistical and computational methods. One used a Kalman Filter, including data from AERONET, NOAA, and other ground-based sources, to estimate global emissions of 17.8+/-5.6 Tg BC/year (with the increase attributable to East Asia, South Asia, Southeast Asia, and Eastern Europe - all regions which have had rapid urban, industrial, and economic expansion). The second additionally used remotely sensed measurements from MISR and a variance maximizing technique, uniquely quantifying fire and urban sources in Southeast Asia, as well as their large year-to-year variability over the past 12 years, leading to increases from 10% to 150%. These new emissions products, when run through our state-of-the art modelling system of chemistry, physics, transport, removal, radiation, and climate, match 140 ground stations and satellites better in both an absolute and a temporal sense. New work now further includes trace species measurements from OMI, which are used with the variance maximizing technique to constrain the types of emissions sources. Furthermore, land-use change and fire estimation products from MODIS are also included, which provide other constraints on the temporal and spatial nature of the variations of intermittent sources like fires or new permanent sources like expanded urbanization. This talk will introduce a new, top-down constrained, weekly varying BC emissions dataset, show that it produces a better fit with observations, and draw conclusions about the sources and impacts from urbanization one hand, and fires on another hand. Results specific to the Southeast and East Asia will demonstrate inter- and intra-annual variations, such as the function of

  7. Constraining the dynamics of the water budget at high spatial resolution in the world's water towers using models and remote sensing data; Snake River Basin, USA

    Science.gov (United States)

    Watson, K. A.; Masarik, M. T.; Flores, A. N.

    2016-12-01

    Mountainous, snow-dominated basins are often referred to as the water towers of the world because they store precipitation in seasonal snowpacks, which gradually melt and provide water supplies to downstream communities. Yet significant uncertainties remain in terms of quantifying the stores and fluxes of water in these regions as well as the associated energy exchanges. Constraining these stores and fluxes is crucial for advancing process understanding and managing these water resources in a changing climate. Remote sensing data are particularly important to these efforts due to the remoteness of these landscapes and high spatial variability in water budget components. We have developed a high resolution regional climate dataset extending from 1986 to the present for the Snake River Basin in the northwestern USA. The Snake River Basin is the largest tributary of the Columbia River by volume and a critically important basin for regional economies and communities. The core of the dataset was developed using a regional climate model, forced by reanalysis data. Specifically the Weather Research and Forecasting (WRF) model was used to dynamically downscale the North American Regional Reanalysis (NARR) over the region at 3 km horizontal resolution for the period of interest. A suite of satellite remote sensing products provide independent, albeit uncertain, constraint on a number of components of the water and energy budgets for the region across a range of spatial and temporal scales. For example, GRACE data are used to constrain basinwide terrestrial water storage and MODIS products are used to constrain the spatial and temporal evolution of evapotranspiration and snow cover. The joint use of both models and remote sensing products allows for both better understanding of water cycle dynamics and associated hydrometeorologic processes, and identification of limitations in both the remote sensing products and regional climate simulations.

  8. How market environment may constrain global franchising in emerging markets

    OpenAIRE

    Baena Graciá, Verónica

    2011-01-01

    Although emerging markets are some of the fastest growing economies in the world and represent countries that are experiencing a substantial economic transformation, little is known about the factors influencing country selection for expansion in those markets. In an attempt to enhance the knowledge that managers and scholars have on franchising expansion, the present study examines how market conditions may constrain international diffusion of franchising in emerging markets. They are: i) ge...

  9. Probabilistic Constrained Load Flow Considering Integration of Wind Power Generation and Electric Vehicles

    DEFF Research Database (Denmark)

    Vlachogiannis, Ioannis (John)

    2009-01-01

    A new formulation and solution of probabilistic constrained load flow (PCLF) problem suitable for modern power systems with wind power generation and electric vehicles (EV) demand or supply is represented. The developed stochastic model of EV demand/supply and the wind power generation model...... are incorporated into load flow studies. In the resulted PCLF formulation, discrete and continuous control parameters are engaged. Therefore, a hybrid learning automata system (HLAS) is developed to find the optimal offline control settings over a whole planning period of power system. The process of HLAS...

  10. Technical evaluation of hybrid membrane/DEA modeling. Topical report, January 1990-August 1990

    International Nuclear Information System (INIS)

    Changela, M.K.; McKee, R.L.; Reading, G.J.

    1991-08-01

    The report examines the potential for cost and/or performance advantages of a hybrid system, the integration of membranes and amines, over a single-stage membrane or amine system for producing pipeline quality gas on a small scale from high carbon dioxide subquality natural gas. The hybrid configuration evaluated is a membrane system in series with a conventional diethanolamine (DEA) system. Comparison of the established costs shows that each system has a region of operability. Membranes offer higher cost savings at low feed flow rates and high carbon dioxide feed contents. The hybrid system offers cost savings over moderate to high feed flow rates and for moderate to high carbon dioxide feed contents. The DEA system offers cost savings for moderate to high feed flow rates at low to moderate carbon dioxide feed contents. Membranes do not exhibit economies of scale which works to their advantage for removing carbon dioxide on a small scale. Processing costs for amine systems are more sensitive to economies of scale, and thus decrease more rapidly than for membranes at higher feed flow rates. The hybrid system offers cost savings in regions that have been perceived as exclusively amine treating applications, thus increasing the area of operability for membranes

  11. Hybrid Thermochemical/Biological Processing

    Science.gov (United States)

    Brown, Robert C.

    The conventional view of biorefineries is that lignocellulosic plant material will be fractionated into cellulose, hemicellulose, lignin, and terpenes before these components are biochemically converted into market products. Occasionally, these plants include a thermochemical step at the end of the process to convert recalcitrant plant components or mixed waste streams into heat to meet thermal energy demands elsewhere in the facility. However, another possibility for converting high-fiber plant materials is to start by thermochemically processing it into a uniform intermediate product that can be biologically converted into a bio-based product. This alternative route to bio-based products is known as hybrid thermochemical/biological processing. There are two distinct approaches to hybrid processing: (a) gasification followed by fermentation of the resulting gaseous mixture of carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2) and (b) fast pyrolysis followed by hydrolysis and/or fermentation of the anhydrosugars found in the resulting bio-oil. This article explores this "cart before the horse" approach to biorefineries.

  12. Determination of dopamine using a glassy carbon electrode modified with a graphene and carbon nanotube hybrid decorated with molybdenum disulfide flowers

    International Nuclear Information System (INIS)

    Mani, Veerappan; Govindasamy, Mani; Chen, Shen-Ming; Karthik, Raj; Huang, Sheng-Tung

    2016-01-01

    We describe a hybrid material that consists of molybdenum sulfide flowers placed on graphene nanosheets and multiwalled carbon nanotubes (GNS-CNTs/MoS_2). It was deposited on a glassy carbon electrode (GCE) which then is well suited for sensitive and selective determination of dopamine. The GNS-CNTs/MoS_2 nanocomposite was prepared by a hydrothermal method and characterized by scanning electron and transmission emission microscopies, energy-dispersive X-ray spectroscopy, cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy. Electrochemical studies show the composite to possess excellent electrochemical properties such as a large electrochemically active surface, high capacitance current, a wide potential window, high conductivity and large porosity. The electrode displays excellent electrocatalytic ability to oxidize dopamine. The modified GCE, best operated at a working potential as low as 0.15 V (vs. Ag/AgCl), responds linearly to dopamine in the 100 nM to 100 μM concentration range. The detection limit is 50 nM, and the sensitivity is 10.81 (± 0.26) μA⋅μM"−"1⋅cm"−"2. The sensor has good selectivity, appreciable stability, repeatability and reproducibility. It was applied to the determination of dopamine in (spiked) biological and pharmaceutical samples. (author)

  13. 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

  14. Visibility and oxidation stability of hybrid-type copper mesh electrodes with combined nickel-carbon nanotube coating

    Science.gov (United States)

    Kim, Bu-Jong; Hwang, Young-Jin; Park, Jin-Seok

    2017-04-01

    Hybrid-type transparent conductive electrodes (TCEs) were fabricated by coating copper (Cu) meshes with carbon nanotube (CNT) via electrophoretic deposition, and with nickel (Ni) via electroplating. For the fabricated electrodes, the effects of the coating with CNT and Ni on their transmittance and reflectance in the visible-light range, electrical sheet resistance, and chromatic parameters (e.g., redness and yellowness) were characterized. Also, an oxidation stability test was performed by exposing the electrodes to air for 20 d at 85 °C and 85% temperature and humidity conditions, respectively. It was discovered that the CNT coating considerably reduced the reflectance of the Cu meshes, and that the Ni coating effectively protected the Cu meshes against oxidation. Furthermore, after the coating with CNT, both the redness and yellowness of the Cu mesh regardless of the Ni coating approached almost zero, indicating a natural color. The experiment results confirmed that the hybrid-type Cu meshes with combined Ni-CNT coating improved characteristics in terms of reflectance, sheet resistance, oxidation stability, and color, superior to those of the primitive Cu mesh, and also simultaneously satisfied most of the requirements for TCEs.

  15. Hybrid Psychology: The marriage of discourse analysis with neuroscience

    Directory of Open Access Journals (Sweden)

    Rom Harré

    2010-07-01

    Full Text Available As the 21st Century opened the controversial and unstable discipline of `academic psychology’ seemed to separating into two radically distinct and perhaps irreconcilable domains. Discursive psychology focused on the management of meaning in a world of norms while Neuropsychology focused on the investigation of brain and cognitive processes. These two domains can be reconciled in a hybrid science that brings them together into a synthesis more powerful than anything psychologists have achieved before. In this paper means Hybrid psychology depends on the intuition that while brains can be assimilated into the world of persons, people cannot be assimilated into the world of cell structures and molecular processes. The project of setting up a hybrid science, in which the symbol using capacities of human beings are brought into a unified scheme with the organic aspects of members of the species homo sapiens, demands the dissolution of the mind-body problem, somehow setting it aside as an illusion, based on a mistaken presupposition.

  16. Fabrication of (PPC/NCC)/PVA composites with inner-outer double constrained structure and improved glass transition temperature.

    Science.gov (United States)

    Cui, Shaoying; Li, Li; Wang, Qi

    2018-07-01

    Improving glass transition temperature (T g ) and mechanical property of the environment-friendly poly(propylene carbonate) via intermacromolecular complexation through hydrogen bonding is attractive and of great importance. A novel and effective strategy to prepare (polypropylene carbonate/nanocrystalline cellulose)/polyvinyl alcohol ((PPC/NCC)/PVA) composites with inner-outer double constrained structure was reported in this work. Outside the PPC phase, PVA, as a strong skeleton at microscale, could constrain the movement of PPC molecular chains by forming hydrogen bonding with PPC at the interface of PPC and PVA phases; inside the PPC phase, the rod-like NCC could restrain the flexible molecular chains of PPC at nanoscale by forming multi-hydrogen bonding with PPC. Under the synergistic effect of this novel inner-outer double constrained structure, T g , mechanical properties and thermal stability of (PPC/NCC)/PVA composite were significantly increased, e.g. T g of the composite researched the maximum value of 49.6 °C, respectively 15.6 °C, 5.7 °C and 4.2 °C higher than that of PPC, PPC/NCC and PPC/PVA composite. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Surface-Induced Hybridization between Graphene and Titanium

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Allen L. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States).; Koch, Roland J. [Technische Universitat, Chemnitz (Germany); Ong, Mitchell T. [Stanford Univ., CA (United States); Fang, Wenjing [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Hofmann, Mario [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Kim, Ki Kang [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States).; Seyller, Thomas [Technische Universitat, Chemnitz (Germany); Dresselhaus, Mildred S. [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Reed, Evan J. [Stanford Univ., CA (United States); Kong, Jing [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Palacios, Tomás [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States)

    2014-08-26

    Carbon-based materials such as graphene sheets and carbon nanotubes have inspired a broad range of applications ranging from high-speed flexible electronics all the way to ultrastrong membranes. However, many of these applications are limited by the complex interactions between carbon-based materials and metals. In this work, we experimentally investigate the structural interactions between graphene and transition metals such as palladium (Pd) and titanium (Ti), which have been confirmed by density functional simulations. We find that the adsorption of titanium on graphene is more energetically favorable than in the case of most metals, and density functional theory shows that a surface induced p-d hybridization occurs between atomic carbon and titanium orbitals. This strong affinity between the two materials results in a short-range ordered crystalline deposition on top of graphene as well as chemical modifications to graphene as seen by Raman and X-ray photoemission spectroscopy (XPS). This induced hybridization is interface-specific and has major consequences for contacting graphene nanoelectronic devices as well as applications toward metal-induced chemical functionalization of graphene.

  18. Combining hybrid cars and synthetic fuels with electricity generation and carbon capture and storage

    International Nuclear Information System (INIS)

    Vliet, Oscar van; Broek, Machteld van den; Turkenburg, Wim; Faaij, Andre

    2011-01-01

    We examined the co-evolution of the transportation, and electricity and heat generation sectors in the Netherlands until 2040 using a MARKAL bottom-up cost optimisation model. All scenario variants investigated indicate a switch away from crude oil-based diesel and petrol for transportation. Lowest overall CO 2 abatement cost is achieved by accommodating transportation first and using relatively expensive options for emissions reduction in electricity generation if needed. Biomass and carbon capture and storage (CCS) are used to full potential. Transportation CO 2 emissions are reduced by switching to ethanol or bio-based synthetic fuels combined with CCS, and series hybrid cars if needed. Depending on the availability of biomass and carbon storage capacity, electricity is produced from biomass, coal with CCS, or wind complemented with natural gas. Indirect greenhouse gas emissions rise to 34-54% of national emissions in 2040. The difference in annual investment required between the scenario variants with and without CO 2 emissions reductions of 68% by 2040 is 4-7 billion euro/year, or 0.5-1.2% of projected GDP. Investment costs are mostly determined by the cost of cars and electricity generation capacity. We observe competition for limited biomass supply and CO 2 storage capacity between the transportation and power sectors.

  19. Biofunctionalization of carbon nanotubes/chitosan hybrids on Ti implants by atom layer deposited ZnO nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Yizhou; Liu, Xiangmei [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, School of Materials Science & Engineering, Hubei University, Wuhan 430062 (China); Yeung, Kelvin W.K. [Division of Spine Surgery, Department of Orthopaedics & Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong (China); Chu, Paul K. [Department of Physics & Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Wu, Shuilin, E-mail: shuilin.wu@gmail.com [Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials, Ministry-of-Education Key Laboratory for the Green Preparation and Application of Functional Materials, Hubei Key Laboratory of Polymer Materials, School of Materials Science & Engineering, Hubei University, Wuhan 430062 (China)

    2017-04-01

    Highlights: • Carbon naonotubes/chitosan/ZnO coating was first constructed on Ti implants. • This system endowed Ti implants with excellent self-antibacterial activity. • The amount of Zn could be precisely controlled by atom layer deposition. • This system could regulate cell behaviors on metallic implants. - Abstract: One-dimensional (1D) nanostructures of ZnO using atomic layer deposition (ALD) on chitosan (CS) modified carbon nanotubes (CNTs) were first introduced onto the surfaces of biomedical implants. When the content of ZnO is not sufficient, CNTs can strengthen the antibacterial activity against E. coli and S. aureus by 8% and 39%, respectively. CS can improve the cytocompatibility of CNTs and ZnO. The amount of Zn content can be controlled by changing the cycling numbers of ALD processes. This hybrid coating can not only endow medical implants with high self-antibacterial efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of over 73% and 98%, respectively, but also regulate the proliferation and osteogenic differentiation of osteoblasts by controlling the amount of ZnO.

  20. Biofunctionalization of carbon nanotubes/chitosan hybrids on Ti implants by atom layer deposited ZnO nanostructures

    International Nuclear Information System (INIS)

    Zhu, Yizhou; Liu, Xiangmei; Yeung, Kelvin W.K.; Chu, Paul K.; Wu, Shuilin

    2017-01-01

    Highlights: • Carbon naonotubes/chitosan/ZnO coating was first constructed on Ti implants. • This system endowed Ti implants with excellent self-antibacterial activity. • The amount of Zn could be precisely controlled by atom layer deposition. • This system could regulate cell behaviors on metallic implants. - Abstract: One-dimensional (1D) nanostructures of ZnO using atomic layer deposition (ALD) on chitosan (CS) modified carbon nanotubes (CNTs) were first introduced onto the surfaces of biomedical implants. When the content of ZnO is not sufficient, CNTs can strengthen the antibacterial activity against E. coli and S. aureus by 8% and 39%, respectively. CS can improve the cytocompatibility of CNTs and ZnO. The amount of Zn content can be controlled by changing the cycling numbers of ALD processes. This hybrid coating can not only endow medical implants with high self-antibacterial efficacy against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of over 73% and 98%, respectively, but also regulate the proliferation and osteogenic differentiation of osteoblasts by controlling the amount of ZnO.

  1. Ultrahigh Carrier Mobility Achieved in Photoresponsive Hybrid Perovskite Films via Coupling with Single-Walled Carbon Nanotubes

    KAUST Repository

    Li, Feng; Wang, Hong; Kufer, Dominik; Liang, Liangliang; Yu, Weili; Alarousu, Erkki; Ma, Chun; Li, Yangyang; Liu, Zhixiong; Liu, Changxu; Wei, Nini; Wang, Fei; Chen, Lang; Mohammed, Omar F.; Fratalocchi, Andrea; Liu, Xiaogang; Konstantatos, Gerasimos; Wu, Tao

    2017-01-01

    Organolead trihalide perovskites have drawn substantial interest for photovoltaic and optoelectronic applications due to their remarkable physical properties and low processing cost. However, perovskite thin films suffer from low carrier mobility as a result of their structural imperfections such as grain boundaries and pinholes, limiting their device performance and application potential. Here we demonstrate a simple and straightforward synthetic strategy based on coupling perovskite films with embedded single-walled carbon nanotubes. We are able to significantly enhance the hole and electron mobilities of the perovskite film to record-high values of 595.3 and 108.7 cm(2) V(-1) s(-1) , respectively. Such a synergistic effect can be harnessed to construct ambipolar phototransistors with an ultrahigh detectivity of 3.7 × 10(14) Jones and a responsivity of 1 × 10(4) A W(-1) , on a par with the best devices available to date. The perovskite/carbon nanotube hybrids should provide a platform that is highly desirable for fields as diverse as optoelectronics, solar energy conversion, and molecular sensing.

  2. Ultrahigh Carrier Mobility Achieved in Photoresponsive Hybrid Perovskite Films via Coupling with Single-Walled Carbon Nanotubes

    KAUST Repository

    Li, Feng

    2017-02-22

    Organolead trihalide perovskites have drawn substantial interest for photovoltaic and optoelectronic applications due to their remarkable physical properties and low processing cost. However, perovskite thin films suffer from low carrier mobility as a result of their structural imperfections such as grain boundaries and pinholes, limiting their device performance and application potential. Here we demonstrate a simple and straightforward synthetic strategy based on coupling perovskite films with embedded single-walled carbon nanotubes. We are able to significantly enhance the hole and electron mobilities of the perovskite film to record-high values of 595.3 and 108.7 cm(2) V(-1) s(-1) , respectively. Such a synergistic effect can be harnessed to construct ambipolar phototransistors with an ultrahigh detectivity of 3.7 × 10(14) Jones and a responsivity of 1 × 10(4) A W(-1) , on a par with the best devices available to date. The perovskite/carbon nanotube hybrids should provide a platform that is highly desirable for fields as diverse as optoelectronics, solar energy conversion, and molecular sensing.

  3. Green-Schwarz superstring: Beltrami parametrization and world-sheet supersymmetric generalization

    International Nuclear Information System (INIS)

    Binetruy, P.; Girardi, G.; Grimm, R.

    1989-06-01

    We study a generalization of the superstring theory in which both world-sheet and space-time supersymmetries are explicit. This hybrid superstring interpolates between the Green-Schwarz and the Ramond-Neveu-Schwarz formulations. We show that the Beltrami parametrization of the world-sheet provides a natural setting for the description of K-transformations already in the Green-Schwarz string. We construct the hybrid superstring action using the (1,1) supersymmetric version of the Beltrami parametrization. We discuss the generalization of k-transformations

  4. Experimental Investigation of the Piezoresistive Properties of Cement Composites with Hybrid Carbon Fibers and Nanotubes

    Directory of Open Access Journals (Sweden)

    Seung-Jung Lee

    2017-11-01

    Full Text Available Cement-based sensors with hybrid conductive fillers using both carbon fibers (CFs and multi-walled carbon nanotubes (MWCNTs were experimentally investigated in this study. The self-sensing capacities of cement-based composites with only CFs or MWCNTs were found based on preliminary tests. The results showed that the percolation thresholds of CFs and MWCNTs were 0.5–1.0 vol.% and 1.0 vol.%, respectively. Based on these results, the feasibility of self-sensing composites with four different amounts of CFs and MWCNTs was considered under cyclic compression loads. When the amount of incorporated CFs increased and the amount of incorporated MWCNTs decreased, the self-sensing capacity of the composites was reduced. It was concluded that cement-based composites containing both 0.1 vol.% CFs and 0.5 vol.% MWCNTs could be an alternative to cement-based composites with 1.0 vol.% MWCNTs in order to achieve equivalent self-sensing performance at half the price. The gauge factor (GF for that composite was 160.3 with an R-square of 0.9274 in loading stages I and II, which was similar to the GF of 166.6 for the composite with 1.0 vol.% MWCNTs.

  5. Hybrid capacitor with activated carbon electrode, Ni(OH){sub 2} electrode and polymer hydrogel electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Nohara, Shinji; Asahina, Toshihide; Wada, Hajime; Furukawa, Naoji; Inoue, Hiroshi; Iwakura, Chiaki [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan); Sugoh, Nozomu; Iwasaki, Hideharu [Kurashiki Research Laboratory, Kuraray Co., Ltd., 2045-1 Sakazu, Kurashiki, Okayama 710-8691 (Japan)

    2006-06-19

    A new hybrid capacitor (HC) cell was assembled using an activated carbon (AC) negative electrode, an Ni(OH){sub 2} positive electrode and a polymer hydrogel electrolyte prepared from crosslinked potassium poly(acrylate) (PAAK) and KOH aqueous solution. The HC cell was characterized compared with an electric double layer capacitor (EDLC) using two AC electrodes and the polymer hydrogel electrolyte. It was found that the HC cell successfully worked in the larger voltage range and exhibited ca. 2.4 times higher capacitance than the EDLC cell. High-rate dischargeability of the HC cell was also superior to that of the EDLC cell. These improved characteristics strongly suggest that the HC cell can be a promising system of capacitors with high energy and power densities. (author)

  6. Economic perspective of hybrid wind-diesel technology for commercial loads of Dhahran Saudi Arabia: A step towards sustainable future

    Directory of Open Access Journals (Sweden)

    Shaahid S.M.

    2015-01-01

    Full Text Available The governments world-wide are deliberating to promote renewable energy sources such as wind to mitigate increasing demand of energy and to overcome effects of pollution due to to use of fossil fuels. Integration of wind turbine generators (WTG with the diesel plants is pursued widely to reduce dependence on fossil-fuels and to reduce carbon emissions. Literature indicates that commercial/residential buildings in the Kingdom of Saudi Arabia (K.S.A consume an estimated 10 - 40% of the total electric energy generated. The aim of this study is to analyze wind-speed data of Dhahran (East-Coast, K.S.A. to assess the economic feasibility of utilizing hybrid wind-diesel power systems to meet the load requirements of a typical commercial building (with annual electrical energy demand of 620,000 kWh. The monthly average wind speeds range from 3.3 to 5.6 m/s. The hybrid systems simulated consist of different combinations of 100 kW commercial WTG supplemented with diesel generators. NREL’s (HOMER Energy’s HOMER software has been employed to perform the techno-economic analysis. The simulation results indicate that for a hybrid system comprising of 100 kW wind capacity together with 175 kW diesel system, the wind penetration (at 37 m hub-height, with 0% annual capacity shortage is 25%. The cost of generating energy (COE, $/kWh from this hybrid wind-diesel system has been found to be 0.121 $/kWh (assuming diesel fuel price of 0.1$/liter. The study exhibits that for a given hybrid configuration, the number of operational hours of diesel gensets decreases with increase in wind farm capacity. Emphasis has also been placed on wind penetration, un-met load, energy production and COE, excess electricity generation, percentage fuel savings and reduction in carbon emissions (relative to diesel-only situation of different hybrid systems, cost break-down of wind-diesel systems, COE of different hybrid systems, etc.

  7. Critical Resources for Emerging Battery Technologies for Hybrid and Electric Vehicles. Proceedings of the International Conference “ISWA World Solid Waste Congress”, 17th - 19th September 2012, Florence, Italy

    DEFF Research Database (Denmark)

    Habib, Komal; Nyander, Nils Christian; Wenzel, Henrik

    2012-01-01

    such as photovoltaics, wind turbines, electric and hybrid cars are, however, in turn dependent on other non- renewable resources such as metals which may become scarce in the future. The concept of ‘critical resources’ is in this context is an expression of how limited or constrained the supply of a resource......-manganese spinel Titanate (LMO – T)) for electric cars in a proposed scenario of 2050, in which a scale of 100 % global conversion of passenger cars to battery cars is modeled. Potential resource supply constraints for these emerging battery technologies in electric cars have been analyzed and assessed...

  8. Performance evaluation of a hybrid system for efficient palm oil mill effluent treatment via an air-cathode, tubular upflow microbial fuel cell coupled with a granular activated carbon adsorption.

    Science.gov (United States)

    Tee, Pei-Fang; Abdullah, Mohammad Omar; Tan, Ivy Ai Wei; Mohamed Amin, Mohamed Afizal; Nolasco-Hipolito, Cirilo; Bujang, Kopli

    2016-09-01

    An air-cathode MFC-adsorption hybrid system, made from earthen pot was designed and tested for simultaneous wastewater treatment and energy recovery. Such design had demonstrated superior characteristics of low internal resistance (29.3Ω) and favor to low-cost, efficient wastewater treatment and power generation (55mW/m(3)) with average current of 2.13±0.4mA. The performance between MFC-adsorption hybrid system was compared to the standalone adsorption system and results had demonstrated great pollutants removals of the integrated system especially for chemical oxygen demand (COD), biochemical oxygen demand (BOD3), total organic carbon (TOC), total volatile solids (TVS), ammoniacal nitrogen (NH3-N) and total nitrogen (TN) because such system combines the advantages of each individual unit. Besides the typical biological and electrochemical processes that happened in an MFC system, an additional physicochemical process from the activated carbon took place simultaneously in the MFC-adsorption hybrid system which would further improved on the wastewater quality. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Self-Volatilization Approach to Mesoporous Carbon Nanotube/Silver Nanoparticle Hybrids: The Role of Silver in Boosting Li Ion Storage.

    Science.gov (United States)

    Jiang, Hao; Zhang, Haoxuan; Fu, Yao; Guo, Shaojun; Hu, Yanjie; Zhang, Ling; Liu, Yu; Liu, Honglai; Li, Chunzhong

    2016-01-26

    One of the biggest challenging issues of carbon nanomaterials for Li ion batteries (LIBs) is that they show low initial Coulombic efficiency (CE), leading to a limited specific capacity. Herein, we demonstrate a simple template self-volatilization strategy for in situ synthesis of mesoporous carbon nanotube/Ag nanoparticle (NP) hybrids (Ag-MCNTs) to boost the LIBs' performance. The key concept of Ag-MCNTs for enhancing LIBs is that a small trace of Ag NPs on MCNTS can greatly restrict the formation of a thicker solid electrolyte interphase film, which has been well verified by both transmission electron microscopy results and quantum density functional theory calculations, leading to the highest initial CE in all the reported carbon nanomaterials. This uncovered property of Ag NPs from Ag-MCNTs makes them exhibit a very high reversible capacity of 1637 mAh g(-1) after 400 discharge/charge cycles at 100 mA g(-1), approximately 5 times higher than the theoretical value of a graphite anode (372 mAh g(-1)), excellent rate capability, and long cycle life.

  10. The origins and behaviour of carbon in a major semi-arid river, the Murray River, Australia, as constrained by carbon isotopes and hydrochemistry

    International Nuclear Information System (INIS)

    Cartwright, Ian

    2010-01-01

    Research highlights: → δ 13 C and concentrations of DIC in Murray River controlled by mineralisation of organic carbon and evasion. → Murray River is source of atmospheric CO 2 . → In-river processing of carbon results in difficulties in determining carbon sources. - Abstract: δ 13 C values of dissolved inorganic C (DIC), dissolved organic C (DOC), and particulate organic C (POC) together with δ 18 O and δ 2 H values of water, δ 34 S values of dissolved SO 4 , and major ion concentrations were measured in the Murray River and its tributaries between November 2005 and April 2007 to constrain the origins and behaviour of riverine C. δ 13 C DIC values in the Murray River vary between -9.5 and -4.7 per mille with a range of 13 C DIC values of the tributaries are -11.0 per mille to -5.1 per mille. DIC concentrations of the Murray River increase from ∼25 mg/L in the middle and upper reaches of the river to 45-55 mg/L in the lower reaches. However, the mass ratio of DIC as a proportion of the total dissolved solids (TDS) decreases from ∼0.6-0.7 in the headwaters to ∼0.2-0.3 in the lower reaches of the river, with similar downstream changes in DIC/Cl ratios. This precludes simple evaporative concentration of DIC and is interpreted as the river evading CO 2 ; this interpretation is consistent with pCO 2 values that are in the range 550-11,200 ppm volume (ppmv), which are far higher than those in equilibrium with the atmosphere (∼360 ppmv). The δ 13 C DIC values are similar to those that would be produced by the weathering of marine limestone (δ 13 C ∼ 0 per mille). However, the lack of marine limestones cropping out in the Murray-Darling Basin and the relatively uniform δ 13 C DIC values of the Murray River (even in upland reaches where the dominant rock types are metamorphosed silicates and granites) make this unlikely. Rather the high pCO 2 values and δ 13 C DIC values are best explained by a combination of mineralisation of low δ 13 C organic C

  11. Direct electrochemistry with enhanced electrocatalytic activity of hemoglobin in hybrid modified electrodes composed of graphene and multi-walled carbon nanotubes.

    Science.gov (United States)

    Sun, Wei; Cao, Lili; Deng, Ying; Gong, Shixing; Shi, Fan; Li, Gaonan; Sun, Zhenfan

    2013-06-05

    A graphene (GR) and multi-walled carbon nanotubes (MWCNT) hybrid was prepared and modified on a 1-hexylpyridinium hexafluorophosphate based carbon ionic liquid electrode (CILE). Hemoglobin (Hb) was immobilized on GR-MWCNT/CILE surface with Nafion as the film forming material and the modified electrode was denoted as Nafion/Hb-GR-MWCNT/CILE. Spectroscopic results revealed that Hb molecules retained its native structure in the GR-MWCNT hybird. Electrochemical behaviors of Hb were carefully investigated by cyclic voltammetry with a pair of well-defined redox peaks obtained, which indicated that direct electron transfer of Hb was realized in the hybrid modified electrode. The result could be attributed to the synergistic effects of GR-MWCNT hybrid with enlarged surface area and improved conductivity through the formation of a three-dimensional network. Electrochemical parameters of the immobilized Hb on the electrode surface were further calculated with the results of the electron transfer number (n) as 1.03, the charge transfer coefficient (a) as 0.58 and the electron-transfer rate constant (ks) as 0.97 s(-1). The Hb modified electrode showed good electrocatalytic ability toward the reduction of different substrates such as trichloroacetic acid in the concentration range from 0.05 to 38.0 mmol L(-1) with a detection limit of 0.0153 mmol L(-1) (3σ), H2O2 in the concentration range from 0.1 to 516.0 mmol L(-1) with a detection limit of 34.9 nmol/L (3σ) and NaNO2 in the concentration range from 0.5 to 650.0 mmol L(-1) with a detection limit of 0.282 μmol L(-1) (3σ). So the proposed electrode had the potential application in the third-generation electrochemical biosensors without mediator. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. The Electrochemical Characteristics of Hybrid Capacitor Prepared by Chemical Activation of NaOH

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jeong Eun; Bae, Ga Yeong; Yang, Jeong Min; Lee, Jong Dae [Chungbuk National Univ., Chungju (Korea, Republic of)

    2013-06-15

    Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481m{sup 2}/g) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using LiMn{sub 2}O{sub 4}, LiCoO{sub 2} as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes (LiPF{sub 6}, TEABF{sub 4}) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using LiMn{sub 2}O{sub 4}/AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg.

  13. Enhanced UV photoresponse of KrF-laser-synthesized single-wall carbon nanotubes/n-silicon hybrid photovoltaic devices.

    Science.gov (United States)

    Le Borgne, V; Gautier, L A; Castrucci, P; Del Gobbo, S; De Crescenzi, M; El Khakani, M A

    2012-06-01

    We report on the KrF-laser ablation synthesis, purification and photocurrent generation properties of single-wall carbon nanotubes (SWCNTs). The thermally purified SWCNTs are integrated into hybrid photovoltaic (PV) devices by spin-coating them onto n-Si substrates. These novel SWCNTs/n-Si hybrid devices are shown to generate significant photocurrent (PC) over the entire 250-1050 nm light spectrum with external quantum efficiencies (EQE) reaching up to ~23%. Our SWCNTs/n-Si hybrid devices are not only photoactive in the traditional spectral range of Si solar cells, but generate also significant PC in the UV domain (below 400 nm). This wider spectral response is believed to be the result of PC generation from both the SWCNTs themselves and the tremendous number of local p-n junctions created at the nanotubes/Si interface. To assess the prevalence of these two contributions, the EQE spectra and J-V characteristics of these hybrid devices were investigated in both planar and top-down configurations, as a function of SWCNTs' film thickness. A sizable increase in EQE in the near UV with respect to the silicon is observed in both configurations, with a more pronounced UV photoresponse in the planar mode, confirming thereby the role of SWCNTs in the photogeneration process. The PC generation is found to reach its maximum for an optimal the SWCNT film thickness, which is shown to correspond to the best trade-off between lowest electrical resistance and highest optical transparency. Finally, by analyzing the J-V characteristics of our SWCNTs/n-Si devices with an equivalent circuit model, we were able to point out the contribution of the various electrical components involved in the photogeneration process. The SWCNTs-based devices demonstrated here open up the prospect for their use in highly effective photovoltaics and/or UV-light sensors.

  14. Chemical sensors are hybrid-input memristors

    Science.gov (United States)

    Sysoev, V. I.; Arkhipov, V. E.; Okotrub, A. V.; Pershin, Y. V.

    2018-04-01

    Memristors are two-terminal electronic devices whose resistance depends on the history of input signal (voltage or current). Here we demonstrate that the chemical gas sensors can be considered as memristors with a generalized (hybrid) input, namely, with the input consisting of the voltage, analyte concentrations and applied temperature. The concept of hybrid-input memristors is demonstrated experimentally using a single-walled carbon nanotubes chemical sensor. It is shown that with respect to the hybrid input, the sensor exhibits some features common with memristors such as the hysteretic input-output characteristics. This different perspective on chemical gas sensors may open new possibilities for smart sensor applications.

  15. High-Flux Carbon Molecular Sieve Membranes for Gas Separation.

    Science.gov (United States)

    Richter, Hannes; Voss, Hartwig; Kaltenborn, Nadine; Kämnitz, Susanne; Wollbrink, Alexander; Feldhoff, Armin; Caro, Jürgen; Roitsch, Stefan; Voigt, Ingolf

    2017-06-26

    Carbon membranes have great potential for highly selective and cost-efficient gas separation. Carbon is chemically stable and it is relative cheap. The controlled carbonization of a polymer coating on a porous ceramic support provides a 3D carbon material with molecular sieving permeation performance. The carbonization of the polymer blend gives turbostratic carbon domains of randomly stacked together sp 2 hybridized carbon sheets as well as sp 3 hybridized amorphous carbon. In the evaluation of the carbon molecular sieve membrane, hydrogen could be separated from propane with a selectivity of 10 000 with a hydrogen permeance of 5 m 3 (STP)/(m 2 hbar). Furthermore, by a post-synthesis oxidative treatment, the permeation fluxes are increased by widening the pores, and the molecular sieve carbon membrane is transformed from a molecular sieve carbon into a selective surface flow carbon membrane with adsorption controlled performance and becomes selective for carbon dioxide. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Ukrainian Hybrid War – Quo Vadis?

    Directory of Open Access Journals (Sweden)

    Rotărescu Carmen

    2015-06-01

    Full Text Available Although it is known for a long time, hybrid war taken place in Ukraine under the umbrella of Russian Federation surprised the whole world and produced the greatest worry for humankind’s fate since the World War II. The political and military analysts appreciate if the World War III does not come will at least follow a long time of a new cold war. Remembering the hybrid war is not declared, can be prolonged in time and the adversary is unknown, thus neither the aggressor state, it is hard to settle which are the countermeasures and how should be act when this clever adversary attacks you using hostile propaganda, to the limit of trick and war perfidy (the first is allowed as method of war, the latter is not, influences the political decision-makers by blackmail, military, economic and energetic deterrence or nuclear bombardments and undergoes subversive, clandestine actions and particularly it is hard to predict their consequences.

  17. Influence of Mixed Solvent on the Electrochemical Property of Hybrid Capacitor.

    Science.gov (United States)

    Lee, Byunggwan; Yoon, J R

    2015-11-01

    The hybrid capacitors (2245 size, cylindrical type) were prepared by using activated carbon cathode and Li4Ti5O12 anode. In order to improve the cell operation at high temperature range, propylene carbonate (PC) was used in combination with acetonitrile (AN) with volume ratio of 7:3, 5:5, and 3:7, respectively. We investigated the electrochemical behavior of the hybrid capacitors that enabled cell operation with stability at high temperature. The organic electrolyte of hybrid capacitor containing PC and AN with a volume ratio 7:3 intended to exhibit highly reversible cycle performance with good capacity retention at 60 degrees C after 2200 cycles. From this study, it has been found that the very strong influence of the solvent nature on the characteristics of hybrid capacitor, and the difference in performance associated with the two solvents.

  18. Modeling real-world fuel consumption and carbon dioxide emissions with high resolution for light-duty passenger vehicles in a traffic populated city

    International Nuclear Information System (INIS)

    Zhang, Shaojun; Wu, Ye; Un, Puikei; Fu, Lixin; Hao, Jiming

    2016-01-01

    Modeling fuel consumption of light-duty passenger vehicles has created substantial concerns due to the uncertainty from real-world operating conditions. Macao is world-renowned for its tourism industry and high population density. An empirical model is developed to estimate real-world fuel consumption and carbon dioxide emissions for gasoline-powered light-duty passenger vehicles in Macao by considering local fleet configuration and operating conditions. Thanks to increasingly stringent fuel consumption limits in vehicle manufacturing countries, estimated type-approval fuel consumption for light-duty passenger vehicles in Macao by model year was reduced from 7.4 L/100 km in 1995 to 5.9 L/100 km in 2012, although a significant upsizing trend has considerably offset potential energy-saving benefit. However, lower driving speed and the air-conditioning usage tend to raise fleet-average fuel consumption and carbon dioxide emission factors, which are estimated to be 10.1 L/100 km and 240 g/km in 2010. Fleet-total fuel consumption and carbon dioxide emissions are modeled through registered vehicle population-based and link-level traffic demand approaches and the results satisfactorily coincide with the historical record of fuel sales in Macao. Temporal and spatial variations in fuel consumption and carbon dioxide emissions from light-duty passenger vehicles further highlight the importance of effective traffic management in congested areas of Macao. - Highlights: • A fuel consumption model is developed for Macao's light-duty passenger cars. • Increased vehicle size partially offset energy benefit from tightened fuel consumption standard. • Lower speed and use of air-conditioning greatly increase fuel use of Macao light-duty passenger cars. • A high resolution inventory of fuel use and carbon dioxide emissions is built with link-level traffic data. • Policy suggestions are provided to mitigate fuel use in a traffic populated city.

  19. World commitment to reduce carbon dioxide emissions

    International Nuclear Information System (INIS)

    Burge, R.

    1991-01-01

    A meeting of energy experts in Toronto, sponsored by the Canadian World Energy Council (CANWEC), to examine the implications of sustainable development for the energy industry, is reported. Canada, according to the World Resources Institute, ranks second only to the Arab oil producers as the world's worst energy hog. Although it contributes only 2% of total world greenhouse gases, its per capita emissions rank higher than even the United States, and this despite the fact that over 75% of its electrical energy is produced by hydro and nuclear power. Its intentions to stabilize CO 2 emissions by 2000 have already been signalled. Although arguments on the supply side strategies of clean coal and nuclear power were presented at the CANWEC meeting, the accent was firmly on demand side management, through energy conservation and efficiency, to meet the challenge of global warming. (author)

  20. An Equilibrium Chance-Constrained Multiobjective Programming Model with Birandom Parameters and Its Application to Inventory Problem

    Directory of Open Access Journals (Sweden)

    Zhimiao Tao

    2013-01-01

    Full Text Available An equilibrium chance-constrained multiobjective programming model with birandom parameters is proposed. A type of linear model is converted into its crisp equivalent model. Then a birandom simulation technique is developed to tackle the general birandom objective functions and birandom constraints. By embedding the birandom simulation technique, a modified genetic algorithm is designed to solve the equilibrium chance-constrained multiobjective programming model. We apply the proposed model and algorithm to a real-world inventory problem and show the effectiveness of the model and the solution method.