WorldWideScience

Sample records for carbon balance part

  1. Carbon balance of the aerial parts of a young hinoki cypress (Chamaecyparis obtusa) stand

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Bredu, S.; Yokota, T.; Hagihara, A. [Nagoya Univ. (Japan)

    1996-01-01

    The aerial carbon balance of a nine year-old stand of hinoki cypress was studied over a one-year period by measuring gross production of various components using the summation method. The summation method consists of measuring respiration, biomass increment, death and shedding of tree parts, tree mortality and grazing by herbivorous insects. Results of the analysis of each of these measurements were reported. No significant difference in carbon content between living and dead organs was found. Gross production, estimated from the summation of respiratory consumption and net production, was 12.11 Mg C ha{sup -}1 year{sup 1}. Overall efficiency, defined as the efficiency with which assimilate is used to produce new plant material (expressed as a ratio of net production to gross production) was 0.57 for this stand, a value significantly higher than those found in two previous studies on an 18-year old and 45-year old cypress stand, respectively. The implication is that overall efficiency decreases with stand age or biomass. 34 refs., 7 figs.

  2. Carbon balance of the aerial parts of a young hinoki cypress (Chamaecyparis obtusa) stand.

    Science.gov (United States)

    Adu-Bredu, Stephen; Yokota, Taketo; Hagihara, Akio

    1996-01-01

    The aerial carbon balance of a 9-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) stand with an aerial biomass of 24.6 Mg(DW) ha(-1) was studied over a 1-year period. Various components that constitute gross production were measured on the basis of the summation method. Respiration of the aerial parts of six sample trees was measured at monthly intervals by an enclosed standing-tree method. The aerial respiration of sample trees was partitioned into growth and maintenance respiration by a two-component model. The growth coefficient varied between 1.2791 and 1.7957 g CO(2) g(DW) (-1) giving a mean value of 1.5223 +/- 0.0729 (SE) g CO(2) g(DW) (-1), whereas the maintenance coefficient ranged between 0.0200 and 0.0373 g CO(2) g(DW) (-1) month(-1) with a mean value of 0.0299 +/- 0.0031 (SE) g CO(2) g(DW) (-1) month(-1). Growth and maintenance respiration of the stand were estimated to be 8.62 and 10.52 Mg CO(2) ha(-1) year(-1), respectively. An open-top cloth trap method was employed to measure the death of the parts of five sample trees. The death of leaves and total organs in the stand were assessed to be 6.26 and 7.60 Mg(DW) ha(-1) year(-1), respectively. Tree mortality and biomass increment were 1.47 and 4.64 Mg(DW) ha(-1) year(-1), respectively. In terms of carbon, respiration, death, grazing and biomass increment were equivalent to 5.22, 4.53, 0.04 and 2.32 Mg C ha(-1) year(-1), respectively. Net production and gross production were estimated to be 6.89 and 12.11 Mg C ha(-1) year(-1), respectively. Biomass accumulation ratio (biomass/net production) and overall efficiency (net production/gross production) were 1.8 and 0.57, respectively.

  3. Impacts of climatic changes on carbon and water balance components of boreal forest ecosystems in central part of European Russia

    Science.gov (United States)

    Olchev, A.; Novenko, E.; Desherevskaya, O.; Kurbatova, J.

    2009-04-01

    Within the framework of the study the possible impacts of climatic changes on carbon and water balances of boreal forest ecosystems of the central part of European Russia for period up to 2100 was estimated using results of model simulations and field measurements. The boreal forests of the Central Forest State Natural Biosphere Reserve (CFSNBR) were selected for the study. They are located at the southern boundary of south taiga zone in the European part of Russia (Tver region) and it can be expected that they will be very sensitive to modern climate warming. Expected future pattern of climatic parameters in the study area was derived using the global climatic model ECHAM5 (MPI Hamburg, Germany) and climatic scenarios B1, A1B and A2 (IPCC 2007). The possible scenarios of species composition changes of the boreal forests were developed using reconstructions of Holocene vegetation cover and climatic conditions on the base of pollen and plant macrofossil analysis of peat profiles in CFSNBR. The annual future pattern of CO2 and H2O fluxes of the forests were simulated using a process-based Mixfor-SVAT model (Olchev et al. 2002, 2008). The main advantage of Mixfor-SVAT is that it allows us to describe CO2 and H2O fluxes both in mono-specific and mixed forest stands. It is able to quantify both total ecosystem fluxes and flux partitioning among different tree species and canopy layers. It is obvious that it can be very helpful to describe accurately effects of species composition changes on structure of dynamics of carbon and water balance of forest ecosystems. Results of modeling experiments show that expected climatic and vegetation changes can have significant impact on evapotranspiration, transpiration, Net Ecosystem Exchange (NEE), Gross (GPP) and Net (NPP) Primary Productivities of boreal forest ecosystems. These changes have a clear seasonal trend and they are depended on species composition of a forest stand. This study was supported by the Russian Foundation

  4. Balanced Flow Meters without Moving Parts

    Science.gov (United States)

    Kelley, Anthony R.; VanBuskirk, Paul

    2008-01-01

    Balanced flow meters are recent additions to an established class of simple, rugged flow meters that contain no moving parts in contact with flow and are based on measurement of pressure drops across objects placed in flow paths. These flow meters are highly accurate, minimally intrusive, easily manufacturable, and reliable. A balanced flow meter can be easily mounted in a flow path by bolting it between conventional pipe flanges. A balanced flow meter can be used to measure the flow of any of a variety of liquids or gases, provided that it has been properly calibrated. Relative to the standard orifice-plate flow meter, the balanced flow meter introduces less turbulence and two times less permanent pressure loss and is therefore capable of offering 10 times greater accuracy and repeatability with less dissipation of energy. A secondary benefit of the reduction of turbulence is the reduction of vibration and up to 15 times less acoustic noise generation. Both the balanced flow meter and the standard orifice-plate flow meter are basically disks that contain holes and are instrumented with pressure transducers on their upstream and downstream faces. The most obvious difference between them is that the standard orifice plate contains a single, central hole while the balanced flow meter contains multiple holes. The term 'balanced' signifies that in designing the meter, the sizes and locations of the holes are determined in an optimization procedure that involves balancing of numerous factors, including volumetric flow, mass flow, dynamic pressure, kinetic energy, all in an effort to minimize such undesired effects as turbulence, pressure loss, dissipation of kinetic energy, and non-repeatability and nonlinearity of response over the anticipated range of flow conditions. Due to proper balancing of these factors, recent testing demonstrated that the balanced flow-meter performance was similar to a Venturi tube in both accuracy and pressure recovery, but featured reduced

  5. Annual carbon balance of a peatland 10 yr following restoration

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    M. Strack

    2013-05-01

    Full Text Available Undisturbed peatlands represent long-term net sinks of carbon; however, peat extraction converts these systems into large and persistent sources of greenhouse gases. Although rewetting and restoration following peat extraction have taken place over the last several decades, very few studies have investigated the longer term impact of this restoration on peatland carbon balance. We determined the annual carbon balance of a former horticulturally-extracted peatland restored 10 yr prior to the study and compared these values to the carbon balance measured at neighboring unrestored and natural sites. Carbon dioxide (CO2 and methane (CH4 fluxes were measured using the chamber technique biweekly during the growing season from May to October 2010 and three times over the winter period. Dissolved organic carbon (DOC export was measured from remnant ditches in the unrestored and restored sites. During the growing season the restored site had greater uptake of CO2 than the natural site when photon flux density was greater than 1000 μmol m−2 s−1, while the unrestored site remained a source of CO2. Ecosystem respiration was similar between natural and restored sites, which were both significantly lower than the unrestored site. Methane flux remained low at the restored site except from open water pools, created as part of restoration, and remnant ditches. Export of DOC during the growing season was 5.0 and 28.8 g m−2 from the restored and unrestored sites, respectively. Due to dry conditions during the study year all sites acted as net carbon sources with annual balance of the natural, restored and unrestored sites of 250.7, 148.0 and 546.6 g C m−2, respectively. Although hydrological conditions and vegetation community at the restored site remained intermediate between natural and unrestored conditions, peatland restoration resulted in a large reduction in annual carbon loss from the system resulting in a carbon balance more similar to a natural

  6. Carbon balance of Russian agricultural land

    Science.gov (United States)

    Schepaschenko, D.; Shvidenko, A.; Schepaschenko, M.

    2012-04-01

    Russia managed 218.7 mln ha agricultural land (2009) in accordance with national statistics (FSSS, 2011: http://www.gks.ru/dbscripts/Cbsd/DBInet.cgi#1). Among that, 91.75 mln ha is arable land; 92.05 mln ha - hayfield and pasture; 34.9 mln ha - abandoned arable and fallow. Abandoned arable area is not indicated directly in the statistics, but can be calculated as a difference between "arable" and "cultivated" area. We estimated carbon balance of agricultural land by accounting carbon fluxes. Carbon sink includes: net primary productivity (NPP), applying fertilizes and liming. Carbon losses include soil respiration (SR), harvest and lateral flux. The initial data (cultivated area and harvest distribution by regions and crop) was derived from national agriculture statistics (FSSS, 2011). NPP was estimated via harvest and set of regression models. Average NPP for agricultural land was estimated at 435 g C m-2 (530 g C m-2 for crops). Soil respiration was calculated by a model (Mukhortova et. al., 1011: http://www.iiasa.ac.at/Research/FOR/forest_cdrom/Articles/Mukhortova_2011_IBFRA_SR.pdf) developed for Russia which is based on all available empirical data and accounted for climatic parameters, soil type and management practice. Average SR of agricultural land is 344 g C m-2 (372 g C m-2 for the cropland). We applied the IPCC method (National inventory, 2010; IPCC, 2006) for fertilizer and lateral fluxes assessment. The total carbon balance of agricultural land is almost in equilibrium (-0.04 t C ha-1) in spite of arable land is a carbon source (-0.84 t C ha-1). The highest sink (1.21 t C ha-1) is provided by abandoned land. Carbon fluxes vary substantially depending on seasonal weather conditions. For example grains' NPP in 2010 (dry and hot summer in major agricultural regions of European Russia) was estimated at 32% less compare to 2009 and the total carbon balance of this land category decreased by order of magnitude. We used Russian land cover (Schepaschenko et al

  7. Simulation of terrestrial carbon cycle balance model in Tibet

    Institute of Scientific and Technical Information of China (English)

    WANGJianlin:; HUDan; SUNZibao

    2003-01-01

    Based on climate material, the simplified terrestrial carbon cycle balance (TCCB) model was established, which is semi-mechanism and semi-statistics. Through TCCB model, our estimate indicates that the southeastern part of the Tibetan Plateau has much higher carbon content, and we have calculated the litter carbon pool, NPP, carbon fluxes and described their spatial characteristics in this region. Based on the TCCB model simulation, NPP in Tibet is 1.73 × 108tC/a, soil organic input rate is 0.66 × l08 tC/a, litter mineralization rate is 1.07× l08tC/a, vegetation litterfall rate is 1.73× l08 tC/a, the litter carbon pool is 7.26 × l08 tC, and soil decomposition rate is 309.54 × l08tC/a. The carbon budget was also analyzed based on the estimates of carbon pool and fluxes. The spatial distributions of carbon pools and carbon fluxes in different compartments of terrestrial ecosystem were depicted with map respectively in Tibet. The distribution of NPP, vegetation litterfall rate, litter, litter mineralization rate, soil organic input rate and the soil decomposition rate were abstracted with temperature, precipitation, fractional vegetation and land feature.

  8. SUSTAINABILITY AS A PART OF BALANCED SCORECARD

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    LUCIE SARA ZAVODNA

    2013-05-01

    Full Text Available Sustainability is a trend, which is more seriously discussed on the international and national level. But also companies in the local level are pushed to have strategies and visions, which enable better future for society, our planet and local economy. Sustainability is one of the conditions – it allows companies to implicate social, economic and environmental pillars to the company´s strategy and management. The question, which remains today is, how to measure social, economic and environmental impact on society? And more – how to enable future generations to have the same conditions as we have today? The paper provides format for a possible bridge between current strategic Balanced Scorecard system and future trend of sustainability. One of the special tools, which can be used for measuring sustainability, is Balanced Scorecard (by Kaplan and Norton in 1990s with the complement of sustainable metrics. The paper introduces three possible methods, which can be used by implementing sustainability into the Balanced Scorecard. One of these methods is described in detail. There is a focus on the sustainable indicators included as the fifth area in Balanced Scorecard model.

  9. Sustainability as a part of balanced scorecard

    Directory of Open Access Journals (Sweden)

    Lucie Sara Zavodna

    2013-05-01

    Full Text Available Sustainability is a trend, which is more seriously discussed on the international and national level. But also companies in the local level are pushed to have strategies and visions, which enable better future for society, our planet and local economy. Sustainability is one of the conditions – it allows companies to implicate social, economic and environmental pillars to the company´s strategy and management. The question, which remains today is, how to measure social, economic and environmental impact on society? And more – how to enable future generations to have the same conditions as we have today? The paper provides format for a possible bridge between current strategic Balanced Scorecard system and future trend of sustainability. One of the special tools, which can be used for measuring sustainability, is Balanced Scorecard (by Kaplan and Norton in 1990s with the complement of sustainable metrics. The paper introduces three possible methods, which can be used by implementing sustainability into the Balanced Scorecard. One of these methods is described in detail. There is a focus on the sustainable indicators included as the fifth area in Balanced Scorecard model.

  10. Terrestrial vegetation redistribution and carbon balance under climate change

    Directory of Open Access Journals (Sweden)

    Erbrecht Tim

    2006-07-01

    Full Text Available Abstract Background Dynamic Global Vegetation Models (DGVMs compute the terrestrial carbon balance as well as the transient spatial distribution of vegetation. We study two scenarios of moderate and strong climate change (2.9 K and 5.3 K temperature increase over present to investigate the spatial redistribution of major vegetation types and their carbon balance in the year 2100. Results The world's land vegetation will be more deciduous than at present, and contain about 125 billion tons of additional carbon. While a recession of the boreal forest is simulated in some areas, along with a general expansion to the north, we do not observe a reported collapse of the central Amazonian rain forest. Rather, a decrease of biomass and a change of vegetation type occurs in its northeastern part. The ability of the terrestrial biosphere to sequester carbon from the atmosphere declines strongly in the second half of the 21st century. Conclusion Climate change will cause widespread shifts in the distribution of major vegetation functional types on all continents by the year 2100.

  11. Drivers and patterns of land biosphere carbon balance reversal

    Science.gov (United States)

    Müller, Christoph; Stehfest, Elke; van Minnen, Jelle G.; Strengers, Bart; von Bloh, Werner; Beusen, Arthur H. W.; Schaphoff, Sibyll; Kram, Tom; Lucht, Wolfgang

    2016-04-01

    The carbon balance of the land biosphere is the result of complex interactions between land, atmosphere and oceans, including climatic change, carbon dioxide fertilization and land-use change. While the land biosphere currently absorbs carbon dioxide from the atmosphere, this carbon balance might be reversed under climate and land-use change (‘carbon balance reversal’). A carbon balance reversal would render climate mitigation much more difficult, as net negative emissions would be needed to even stabilize atmospheric carbon dioxide concentrations. We investigate the robustness of the land biosphere carbon sink under different socio-economic pathways by systematically varying climate sensitivity, spatial patterns of climate change and resulting land-use changes. For this, we employ a modelling framework designed to account for all relevant feedback mechanisms by coupling the integrated assessment model IMAGE with the process-based dynamic vegetation, hydrology and crop growth model LPJmL. We find that carbon balance reversal can occur under a broad range of forcings and is connected to changes in tree cover and soil carbon mainly in northern latitudes. These changes are largely a consequence of vegetation responses to varying climate and only partially of land-use change and the rate of climate change. Spatial patterns of climate change as deduced from different climate models, substantially determine how much pressure in terms of global warming and land-use change the land biosphere will tolerate before the carbon balance is reversed. A reversal of the land biosphere carbon balance can occur as early as 2030, although at very low probability, and should be considered in the design of so-called peak-and-decline strategies.

  12. Carbon and nitrogen balances for six shrublands across Europe

    DEFF Research Database (Denmark)

    Beier, Claus; Emmett, Bridget A.; Tietema, Albert

    2009-01-01

    and nitrogen balances of six shrublands along a climatic gradient across the European continent. The aim of the study was to provide a basis for assessing the range and variability in carbon storage in European shrublands. Across the sites the net carbon storage in the systems ranged from 1,163 g C m−2 to 18...... with a cold and wet climate where soil C constitutes 95% of the total carbon in the ecosystem. Respiration of carbon from the soil organic matter pool dominated the carbon loss at all sites while carbon loss from aboveground litter decomposition appeared less important. Total belowground carbon allocation...

  13. Human footprint affects US carbon balance more than climate change

    Science.gov (United States)

    Bachelet, Dominique; Ferschweiler, Ken; Sheehan, Tim; Baker, Barry; Sleeter, Benjamin M.; Zhu, Zhiliang

    2017-01-01

    The MC2 model projects an overall increase in carbon capture in conterminous United States during the 21st century while also simulating a rise in fire causing much carbon loss. Carbon sequestration in soils is critical to prevent carbon losses from future disturbances, and we show that natural ecosystems store more carbon belowground than managed systems do. Natural and human-caused disturbances affect soil processes that shape ecosystem recovery and competitive interactions between native, exotics, and climate refugees. Tomorrow's carbon budgets will depend on how land use, natural disturbances, and climate variability will interact and affect the balance between carbon capture and release.

  14. Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

    NARCIS (Netherlands)

    Kindler, R.; Siemens, J.; Kaiser, K.; Moors, E.J.

    2011-01-01

    Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH4), at forests, grasslands, and

  15. Computerized calculation of material balances in carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Chistyakov, A.M.

    1980-09-01

    Charge formulations and carbonisation schedules are described by empirical formulae used to calculate the yield of coking products. An algorithm is proposed for calculating the material balance, and associated computer program. The program can be written in conventional languages, e.g. Fortran, Algol etc. The information obtained can be used for on-line assessment of the effects of charge composition and properties on the coke and by-products yields, as well as the effects of the carbonisation conditions.

  16. Impact of rapeseed cropping on the soil carbon balance

    Science.gov (United States)

    Moffat, Antje Maria; Herbst, Mathias; Huth, Vytas; Andres, Monique; Augustin, Jürgen

    2015-04-01

    Winter oilseed rape is the dominant biofuel crop in the young moraine landscape in Northern Germany. Since the cultivation of biofuel crops requires sustainability compared to fossil fuels by law, detailed knowledge about their green house gas (GHG) balance is necessary. The soil carbon balance is one of the key contributors to the total GHG balance and also very important for the assessment of soil fertility. However, the knowledge about the impact of different management practices on the soil carbon balance is very limited up to now. Therefore, we investigated the carbon fluxes of winter oilseed rape at field plots near Dedelow/Uckermark in NE Germany with different treatments of fertilization (mineral versus organic) and tillage (no-till and mulch-till versus ploughing). The dynamics of the carbon fluxes are mainly driven by the current climatic conditions but the overall response depends strongly on the ecosystem state (with its physiological and microbiological properties) which is affected by management. To get the full carbon flux dynamics but also the impact of the different management practices, two different approaches were used: The eddy covariance technique to get continuous fluxes throughout the year and the manual chamber technique to detect flux differences between specific management practices. The manual chamber measurements were conducted four-weekly as all-day campaigns using a flow-through non-steady-state closed chamber system. The fluxes in-between campaigns were gap-filled based on functional relationships with soil and air temperature (for the ecosystem respiration) and photosynthetic active radiation (for the gross primary production). All results presented refer to the cropping season 2012-2013. The combination of the two measurement techniques allows the evaluation of chamber fluxes including an independent estimate of the error on the overall balances. Despite the considerable errors, there are significant differences in the soil carbon

  17. Drought sensitivity of Amazonian carbon balance revealed by atmospheric measurements.

    Science.gov (United States)

    Gatti, L V; Gloor, M; Miller, J B; Doughty, C E; Malhi, Y; Domingues, L G; Basso, L S; Martinewski, A; Correia, C S C; Borges, V F; Freitas, S; Braz, R; Anderson, L O; Rocha, H; Grace, J; Phillips, O L; Lloyd, J

    2014-02-06

    Feedbacks between land carbon pools and climate provide one of the largest sources of uncertainty in our predictions of global climate. Estimates of the sensitivity of the terrestrial carbon budget to climate anomalies in the tropics and the identification of the mechanisms responsible for feedback effects remain uncertain. The Amazon basin stores a vast amount of carbon, and has experienced increasingly higher temperatures and more frequent floods and droughts over the past two decades. Here we report seasonal and annual carbon balances across the Amazon basin, based on carbon dioxide and carbon monoxide measurements for the anomalously dry and wet years 2010 and 2011, respectively. We find that the Amazon basin lost 0.48 ± 0.18 petagrams of carbon per year (Pg C yr(-1)) during the dry year but was carbon neutral (0.06 ± 0.1 Pg C yr(-1)) during the wet year. Taking into account carbon losses from fire by using carbon monoxide measurements, we derived the basin net biome exchange (that is, the carbon flux between the non-burned forest and the atmosphere) revealing that during the dry year, vegetation was carbon neutral. During the wet year, vegetation was a net carbon sink of 0.25 ± 0.14 Pg C yr(-1), which is roughly consistent with the mean long-term intact-forest biomass sink of 0.39 ± 0.10 Pg C yr(-1) previously estimated from forest censuses. Observations from Amazonian forest plots suggest the suppression of photosynthesis during drought as the primary cause for the 2010 sink neutralization. Overall, our results suggest that moisture has an important role in determining the Amazonian carbon balance. If the recent trend of increasing precipitation extremes persists, the Amazon may become an increasing carbon source as a result of both emissions from fires and the suppression of net biome exchange by drought.

  18. CO2 exchange and carbon balance in two grassland sites on eutrophic drained peat soils

    NARCIS (Netherlands)

    Veenendaal, E.M.; Kolle, O.; Leffelaar, P.A.; Schrier-Uijl, A.P.; Huissteden, van J.; Walsem, van J.D.; Moller, F.; Berendse, F.

    2007-01-01

    In this study we investigated the role of intensive and extensive dairy farm practices on CO2 exchange and the carbon balance of peatlands by means of eddy covariance (EC) measurements. Year long EC measurements were made in two adjacent farm sites on peat soil in the western part of the Netherlands

  19. The carbon balance of Africa: synthesis of recent research studies.

    Science.gov (United States)

    Ciais, P; Bombelli, A; Williams, M; Piao, S L; Chave, J; Ryan, C M; Henry, M; Brender, P; Valentini, R

    2011-05-28

    The African continent contributes one of the largest uncertainties to the global CO(2) budget, because very few long-term measurements are carried out in this region. The contribution of Africa to the global carbon cycle is characterized by its low fossil fuel emissions, a rapidly increasing population causing cropland expansion, and degradation and deforestation risk to extensive dryland and savannah ecosystems and to tropical forests in Central Africa. A synthesis of the carbon balance of African ecosystems is provided at different scales, including observations of land-atmosphere CO(2) flux and soil carbon and biomass carbon stocks. A review of the most recent estimates of the net long-term carbon balance of African ecosystems is provided, including losses from fire disturbance, based upon observations, giving a sink of the order of 0.2 Pg C yr(-1) with a large uncertainty around this number. By comparison, fossil fuel emissions are only of the order of 0.2 Pg C yr(-1) and land-use emissions are of the order of 0.24 Pg C yr(-1). The sources of year-to-year variations in the ecosystem carbon-balance are also discussed. Recommendations for the deployment of a coordinated carbon-monitoring system for African ecosystems are given.

  20. The Sub-Saharan Africa carbon balance, an overview

    Directory of Open Access Journals (Sweden)

    A. Bombelli

    2009-02-01

    Full Text Available This study presents a summary overview of the carbon balance of Sub-Saharan Africa (SSA by synthesizing the available data from national communications to UNFCCC and first results from the project CarboAfrica (net ecosystem productivity and emissions from fires, deforestation and forest degradation, by field and model estimates. According to these preliminary estimates the overall carbon balance of SSA varies from 0.43 Pg C y−1 (using in situ measurements for savanna NEP to a much higher sink of 2.53 Pg C y−1 (using model estimates for savanna NEP. UNFCCC estimates lead to a moderate carbon sink of 0.58 Pg C y−1. Excluding anthropogenic disturbance and intrinsic episodic events, the carbon uptake by forests (0.98 Pg C y−1 and savannas (from 1.38 to 3.48 Pg C y−1, depending on the used methodology are the main components of the SSA sink effect. Fires (0.72 Pg C y−1, deforestation (0.25 Pg C y−1 and forest degradation (0.77 Pg C y−1 are the main contributors to the SSA carbon emissions, while the agricultural sector contributes only with 0.12 Pg C y−1. Notably, the impact of forest degradation is higher than that caused by deforestation, and the SSA forest net carbon balance is close to equilibrium. Savannas play a major role in shaping the SSA carbon balance, due to their large areal extent, their fire regime, and their strong interannual NEP variability, but they are also a major uncertainty in the overall budget. This paper shows that Africa plays a key role in the global carbon cycle system and probably could have a potential for carbon sequestration higher than expected, even if still highly uncertain. Further investigations are needed, particularly to better address the role of savannas and tropical forests. The current CarboAfrica network of carbon measurements could provide future unique data sets for better estimating the

  1. A carbon balance model for the great dismal swamp ecosystem

    Science.gov (United States)

    Sleeter, Rachel; Sleeter, Benjamin M.; Williams, Brianna; Hogan, Dianna; Hawbaker, Todd J.; Zhu, Zhiliang

    2017-01-01

    BackgroundCarbon storage potential has become an important consideration for land management and planning in the United States. The ability to assess ecosystem carbon balance can help land managers understand the benefits and tradeoffs between different management strategies. This paper demonstrates an application of the Land Use and Carbon Scenario Simulator (LUCAS) model developed for local-scale land management at the Great Dismal Swamp National Wildlife Refuge. We estimate the net ecosystem carbon balance by considering past ecosystem disturbances resulting from storm damage, fire, and land management actions including hydrologic inundation, vegetation clearing, and replanting.ResultsWe modeled the annual ecosystem carbon stock and flow rates for the 30-year historic time period of 1985–2015, using age-structured forest growth curves and known data for disturbance events and management activities. The 30-year total net ecosystem production was estimated to be a net sink of 0.97 Tg C. When a hurricane and six historic fire events were considered in the simulation, the Great Dismal Swamp became a net source of 0.89 Tg C. The cumulative above and below-ground carbon loss estimated from the South One and Lateral West fire events totaled 1.70 Tg C, while management activities removed an additional 0.01 Tg C. The carbon loss in below-ground biomass alone totaled 1.38 Tg C, with the balance (0.31 Tg C) coming from above-ground biomass and detritus.ConclusionsNatural disturbances substantially impact net ecosystem carbon balance in the Great Dismal Swamp. Through alternative management actions such as re-wetting, below-ground biomass loss may have been avoided, resulting in the added carbon storage capacity of 1.38 Tg. Based on two model assumptions used to simulate the peat system, (a burn scar totaling 70 cm in depth, and the soil carbon accumulation rate of 0.36 t C/ha−1/year−1 for Atlantic white cedar), the total soil carbon loss from the

  2. Carbon and water vapor balance in a subtropical pine plantation

    Directory of Open Access Journals (Sweden)

    Posse G

    2016-10-01

    Full Text Available Afforestation has been proposed as an effective tool for protecting primary and/or secondary forests and for mitigating atmospheric CO2. However, the dynamics of primary productivity differs between plantations and natural forests. The objective of this work was to evaluate the potential for carbon storage of a commercial pine plantation by determining its carbon balance. Measurements started when trees were aged 6 and ended when they were older than 8 years. We measured CO2 and water vapor concentrations using the Eddy covariance method. Gross primary productivity in 2010 and 2011 was 4290 ± 473 g C m-2 and 4015 ± 485 g C m-2, respectively. Ecosystem respiration ranged between 7 and 20 g C m-2 d-1, reaching peaks in all Februaries. Of the 30 months monitored, the plantation acted as carbon source for 21 months and as carbon sink for 6 months, while values close to neutrality were obtained during 3 months. The positive balance representing CO2 loss by the system was most likely due to the cut branches left on the ground following pruning activities. The plantation was subjected to pruning in January and September 2008 and to sanitary pruning in October 2010. In all cases, cut branches were not removed but remained on the ground. Residue management seems to have a very important impact on carbon balance.

  3. Simulating the carbon balance in reclaimed forest ecosystems with the FORECAST model

    Energy Technology Data Exchange (ETDEWEB)

    Welham, C. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Forest Sciences, Forest Ecosystem Simulation Group; ForRx Consulting, Belcarra, BC (Canada); 3GreenTree Ecosystem Services Ltd., Belcarra, BC (Canada)

    2010-07-01

    Large emission sources are beginning to report their carbon footprint on an annual basis as a result of government mandates, shareholder demand for disclosure of a company's risk to climate change, and as part of corporate social responsibility initiatives. Oil sands mining is a carbon intensive activity from the perspective of carbon dioxide emissions. The intensity of carbon emissions can be mitigated through technological and process innovations. However, reclamation is the only mining-related activity that directly removes atmospheric carbon dioxide. This presentation described a modeling exercise that had 3 principal objectives, notably to simulate the carbon balance in a developing reclaimed upland forest ecosystem; to explore the relative change in carbon pools over time; and to compare the carbon balance of the reclaimed ecosystem to its natural analogue. The presentation provided a description of the model and methodology and discussed the simulation protocol. Imperial Oil's Kearl Lake operation, which was used as a test case, showed that approximately 83,000 tonnes of carbon dioxide per hectare can be sequestered per year as a result of reclamation. tabs., figs.

  4. The carbon balance of terrestrial ecosystems of China

    Directory of Open Access Journals (Sweden)

    Pilli R

    2009-05-01

    Full Text Available A comment is made on a recent letter published on Nature, in which different methodologies are applied to estimate the carbon balance of terrestrial ecosystems of China. A global carbon sink of 0.19-0.26 Pg per year is estimated during the 1980s and 1990s, and it is estimated that in 2006 terrestrial ecosystems have absorbed 28-37 per cent of global carbon emissions in China. Most of the carbon absorption is attributed to large-scale plantation made since the 1980s and shrub recovery. These results will certainly be valuable in the frame of the so-called “REDD” (Reducing Emissions from Deforestation forest Degradation in developing countries mechanism (UN convention on climate change UNFCCC.

  5. Measuring the impact of gully erosion on peatland carbon balance

    Science.gov (United States)

    Evans, Martin; James, Rothwell; John, Lindsay

    2010-05-01

    Gully erosion impacts on the carbon balance of peatlands in three ways 1) direct erosional loss of carbon, 2) Enhanced near gully decomposition due to reduced water tables, and 3) Loss of primary productivity in gullies. Representative impacts of the first two mechanisms can be derived from detailed mapping of gully extent, the third requires direct measurement of carbon sequestration. In this paper rates of sequestration at both gully edge and intact sites are compared based on multiple approaches to peat core dating (timescales of circa 30 years) , and compared with equivalent data at millennial scales estimated from published peat growth rate data. The results indicate that whilst there is a clearly demonstrable reduction in carbon sequestration due to gully erosion that at the landscape scale the direct impact of gullying through POC loss and reduced productivity is of greater importance

  6. Environmental change and the carbon balance of Amazonian forests.

    Science.gov (United States)

    Aragão, Luiz E O C; Poulter, Benjamin; Barlow, Jos B; Anderson, Liana O; Malhi, Yadvinder; Saatchi, Sassan; Phillips, Oliver L; Gloor, Emanuel

    2014-11-01

    Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21st Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990s mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990s and early 2000s to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) Pg C year(-1) in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP = -0.06 (-0.31 to +0.01) Pg C year(-1) ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency.

  7. Characteristics of water and carbon balance in moso bamboo forests

    Science.gov (United States)

    Kume, T.; Laplace, S.; Tseng, H.; Hsieh, Y.; Wey, T.; Komatsu, H.

    2013-12-01

    Water and carbon cycles in mountainous areas can have considerable impacts on our available nature resources such as water resources and timber production. Thus, it is indispensable to clarify the difference of water and carbon balances between different types of forested ecosystems. Recently, bamboo forests have been expanding by replacing surrounding vegetation such as coniferous and broad-leaved forests in eastern Asian countries. It has been speculated that the replacements by bamboo forests could alter the vegetation water and carbon cycles. However, our knowledge for the bamboo forests was still limited due to lack of applicable methodology based on a field measurement. To clarify the potential impacts of bamboo expansion on water and carbon cycles, our previous study established optimal and effective design for assessing bamboo forest water use (ie, transpiration) based on sap flux measurements. Using the method, we quantified stand-scale transpiration in bamboo forests and coniferous forests in Taiwan. Consequently, we found significantly larger transpiration in bamboo forests compared with those of surrounding vegetation due to larger canopy conductance in bamboo forests. The unique characteristics of the water use accompanied larger carbon assimilation and soil CO2 efflux in bamboo forests.

  8. The carbon-nitrogen balance of the nodule and its regulation under elevated carbon dioxide concentration.

    Science.gov (United States)

    Libault, Marc

    2014-01-01

    Legumes have developed a unique way to interact with bacteria: in addition to preventing infection from pathogenic bacteria like any other plant, legumes also developed a mutualistic symbiotic relationship with one gender of soil bacteria: rhizobium. This interaction leads to the development of a new root organ, the nodule, where the differentiated bacteria fix for the plant the atmospheric dinitrogen (atmN2). In exchange, the symbiont will benefit from a permanent source of carbon compounds, products of the photosynthesis. The substantial amounts of fixed carbon dioxide dedicated to the symbiont imposed to the plant a tight regulation of the nodulation process to balance carbon and nitrogen incomes and outcomes. Climate change including the increase of the concentration of the atmospheric carbon dioxide is going to modify the rates of plant photosynthesis, the balance between nitrogen and carbon, and, as a consequence, the regulatory mechanisms of the nodulation process. This review focuses on the regulatory mechanisms controlling carbon/nitrogen balances in the context of legume nodulation and discusses how the change in atmospheric carbon dioxide concentration could affect nodulation efficiency.

  9. Carbon and energy balances for a range of biofuels options

    Energy Technology Data Exchange (ETDEWEB)

    Elsayed, M.A.; Matthews, R.; Mortimer, N.D.

    2003-03-01

    This is the final report of a project to produce a set of baseline energy and carbon balances for a range of electricity, heat and transport fuel production systems based on biomass feedstocks. A list of 18 important biofuel technologies in the UK was selected for study of their energy and carbon balances in a consistent approach. Existing studies on these biofuel options were reviewed and their main features identified in terms of energy input, greenhouse gas emissions (carbon dioxide, methane, nitrous oxide and total), transparency and relevance. Flow charts were produced to represent the key stages of the production of biomass and its conversion to biofuels. Outputs from the study included primary energy input per delivered energy output, carbon dioxide outputs per delivered energy output, methane output per delivered energy output, nitrous oxide output per delivered energy output and total greenhouse gas requirements. The net calorific value of the biofuel is given where relevant. Biofuels studied included: biodiesel from oilseed rape and recycled vegetable oil; combined heat and power (CHP) by combustion of wood chip from forestry residues; CHP by gasification of wood chip from short rotation coppice; electricity from the combustion of miscanthus, straw, wood chip from forestry residues and wood chip from short rotation coppice; electricity from gasification of wood chip from forestry residues and wood chip from short rotation coppice; electricity by pyrolysis of wood chip from forestry residues and wood chip from short rotation coppice; ethanol from lignocellulosics, sugar beet and wheat; heat (small scale) from combustion of wood chip from forestry residues and wood chip from short rotation coppice; and rapeseed oil from oilseed rape.

  10. Carbon balance of a grazed grassland in Belgium

    Science.gov (United States)

    Jérôme, E.; Beckers, Y.; Bodson, B.; Moureaux, C.; Aubinet, M.

    2012-04-01

    This work seeks to analyze the C balance of a Belgian grassland grazed by the "Blanc Bleu Belge" breed of cattle. The site is located at Dorinne in the Belgian Condroz (50° 18' 44" N; 4° 58' 07" E; 248 m asl.). It is permanent grassland of ca. 4.2 ha with a moderate slope of 1 to 2 %. Homogeneity and topography criteria are met to ensure high quality turbulent flux measurements. The experimental field was equipped with an eddy covariance system. Flux correction, quality control and data gap filling were performed following standardised procedures. This device was completed by a micrometeorological station that measured temperature and humidity respectively in the air and within the soil, radiation, atmospheric pressure and precipitations. Carbon exported through mowing (CNBP,export), imported through compost application (CNBP,import) or through complementary feeds for cattle (CNBP,complement) was also measured. In addition, the vegetation development was followed in order to estimate herbage production and dry matter intake by grazing animals. Carbon lost through CH4 emissions (CNBP,CH4) was finally estimated, allowing the establishment of a full C budget. After one year of measurements (May 2010 - May 2011), the grassland was a net CO2 source (Net Ecosystem Exchange (NEE) = 172 ± 94 g C m-2 year-1). Net Biome Productivity (NBP) was calculated from NEE by taking into account imports and export of organic C and losses of carbon as CH4. Contribution of CNBP,CH4to NBP was small as it was 12 ± 1 g C m-2 year-1. The balance between CNBP,import and CNBP,export created not such a large departure of NBP from NEE, which is not the case of CNBP,complement. The NBP was finally estimated at 102 ± 95 g C m-2 year-1. At this stage, it is premature to conclude about the sink or source behaviour of the plot because the NBP value is very close to its uncertainty. Moreover, this result was obtained under particular climate conditions, characterised by drought during summer 2010

  11. Carbonate Beaches: A Balance Between Biological and Physical Processes

    Science.gov (United States)

    Nairn, R.; Risk, M.

    2004-12-01

    Carbonate beaches are a unique example of the interaction between biological processes, creating the sediments, and physical processes, moving and often removing the sediments. On the sediment supply side, carbonate sediments are born, not made. They exist in dynamic equilibrium between production and destruction. Following the creation of carbonate sediment in coral reef and lagoon environments, the sediments are moved shoreward to the beach, transport along the shore and sometimes, eventually lost offshore, often as the result of tropical storms. Comprehensive studies of the balance between the supply and loss of carbonate sediments and beach dynamics have been completed for the islands of Mauritius and Barbados. Field studies and remote sensing (Compact Airborne Spectrometry Imaging) have been applied to develop carbonate sediment production rates for a range of reef and lagoon conditions. Using GIS, these production rates have been integrated to determine sediment supply rates for different segments of the coastline. 1-D and 2-D models of waves, hydrodynamics, sediment transport and morphodynamics were set-up and tested against observed beach response to storm events or a sequence of storm events. These complex deterministic models are not suitable for application over periods of decades. However, it was possible to characterize storm events by the extent of sand loss, and relate this to key descriptive factors for groups of storm events, thereby encapsulating the erosion response. A long-term predictive tool for evaluating beach erosion and accretion response, over a period of several decades, was developed by combining the supply rates for carbonate sediment and the encapsulated representation of the loss rates through physical processes. The ability of this predictive tool was successfully tested against observed long term beach evolution along sections of the coast in Barbados and Mauritius using air photo analysis in GIS for shoreline change over periods

  12. Arctic Browning: vegetation damage and implications for carbon balance.

    Science.gov (United States)

    Treharne, Rachael; Bjerke, Jarle; Emberson, Lisa; Tømmervik, Hans; Phoenix, Gareth

    2016-04-01

    'Arctic browning' is the loss of biomass and canopy in Arctic ecosystems. This process is often driven by climatic and biological extreme events - notably extreme winter warm periods, winter frost-drought and severe outbreaks of defoliating insects. Evidence suggests that browning is becoming increasingly frequent and severe at the pan-arctic scale, a view supported by observations from more intensely observed regions, with major and unprecedented vegetation damage reported at landscape (>1000km2) and regional (Nordic Arctic Region) scales in recent years. Critically, the damage caused by these extreme events is in direct opposition to 'Arctic greening', the well-established increase in productivity and shrub abundance observed at high latitudes in response to long-term warming. This opposition creates uncertainty as to future anticipated vegetation change in the Arctic, with implications for Arctic carbon balance. As high latitude ecosystems store around twice as much carbon as the atmosphere, and vegetation impacts are key to determining rates of loss or gain of ecosystem carbon stocks, Arctic browning has the potential to influence the role of these ecosystems in global climate. There is therefore a clear need for a quantitative understanding of the impacts of browning events on key ecosystem carbon fluxes. To address this, field sites were chosen in central and northern Norway and in Svalbard, in areas known to have been affected by either climatic extremes or insect outbreak and subsequent browning in the past four years. Sites were chosen along a latitudinal gradient to capture both conditions already causing vegetation browning throughout the Norwegian Arctic, and conditions currently common at lower latitudes which are likely to become more damaging further North as climate change progresses. At each site the response of Net Ecosystem CO2 Exchange to light was measured using a LiCor LI6400 Portable Photosynthesis system and a custom vegetation chamber with

  13. The Energy Balance Experiment EBEX-2000. Part I: Overview and energy balance

    NARCIS (Netherlands)

    Oncley, S.P.; Foken, T.; Vogt, R.; Kohsiek, W.; Debruin, H.A.R.; Bernhofer, C.; Christen, A.; Gorsel, van E.; Grantz, D.; Feigenwinter, C.; Lehner, I.; Liebethal, C.; Liu, H.; Mauder, M.; Pitacco, A.; Ribeiro, L.; Weidinger, T.

    2007-01-01

    An overview of the Energy Balance Experiment (EBEX-2000) is given. This experiment studied the ability of state-of-the-art measurements to close the surface energy balance over a surface (a vegetative canopy with large evapotranspiration) where closure has been difficult to obtain. A flood-irrigated

  14. Significance of erosion-induced carbon fluxes in the carbon balance of a Mediterranean catchment

    Science.gov (United States)

    Nadeu, Elisabet; de Vente, Joris; Boix-Fayos, Carolina

    2014-05-01

    Large uncertainties surround our knowledge of the processes through which carbon (C) sequestration takes place in terrestrial ecosystems. Nevertheless, terrestrial ecosystems could be capturing up to one fourth of the CO2 that is emitted annually to the atmosphere from the burning of fossil fuels and land use changes. Soils are the third largest C reservoir in the C cycle, storing around 1500 Gt of C. Over the last decades, geomorphologists and soil scientists have claimed the role of soil erosion within the C cycle and its potential contribution to the terrestrial C sink. In order to assess the impact of soil erosion on the C cycle, however, an understanding and quantification of the impact of soil erosion on soil C stocks is needed. This implies quantifying lateral and vertical C fluxes associated to detachment, transport and deposition of soil and sediment at different spatial scales. As an example, we present a C budget for a mountainous catchment in south-eastern Spain for a 28 year study period during which the catchment underwent significant land use changes and hydrological correction works (i.e. check-dam construction and reforestations). We quantified lateral C fluxes induced by soil erosion processes and closed a soil/sediment C budget by combining field measurements and numerical modeling. In addition, correlation analysis was conducted between catchment properties (topographic, land use, lithology) and measured C deposition rates to understand the controlling factors on C yield (export) and C concentration in sediments. The results showed that the highest C yields (associated to high sediment yields) were found in subcatchments dominated by soft lithologies and high drainage densities. On the other hand, C concentration in deposited sediments was higher in areas dominated by forest cover, and presented high variability in those parts of the catchment with smoother slopes. Overall, we estimated that around 4000 Mg of C were mobilized from the catchment

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

    Directory of Open Access Journals (Sweden)

    L. Belelli Marchesini

    2007-01-01

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

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

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

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

  16. Simulated Net Ecosystem Carbon Balance of Western US Forests Under Contemporary Climate and Management

    Science.gov (United States)

    Yang, Z.; Law, B. E.; Jones, M. O.

    2015-12-01

    Previous projections of the contemporary forest carbon balance in the western US showed uncertainties associated with impacts of climate extremes and a coarse spatio-temporal resolution implemented over heterogeneous mountain regions. We modified the Community Land Model (CLM) 4.5 to produce 4km resolution forest carbon changes with drought, fire and management in the western US. We parameterized the model with species data using local plant trait observations for 30 species. To quantify uncertainty, we evaluated the model with data from flux sites, inventories and ancillary data in the region. Simulated GPP was lower than the measurements at our AmeriFlux sites by 17-22%. Simulated burned area was generally higher than Landsat observations, suggesting the model overestimates fire emissions with the new fire model. Landsat MTBS data show high severity fire represents only a small portion of the total burnt area (12-14%), and no increasing trend from 1984 to 2011. Moderate severity fire increased ~0.23%/year due to fires in the Sierra Nevada (Law & Waring 2014). Oregon, California, and Washington were a net carbon sink, and net ecosystem carbon balance (NECB) declined in California over the past 15 years, partly due to drought impacts. Fire emissions were a small portion of the regional carbon budget compared with the effect of harvest removals. Fossil fuel emissions in CA are more than 3x that of OR and WA combined, but are lower per capita. We also identified forest regions that are most vulnerable to climate-driven transformations and to evaluate the effects of management strategies on forest NECB. Differences in forest NECB among states are strongly influenced by the extent of drought (drier longer in the SW) and management intensity (higher in the PNW).

  17. The Acid-Base balance history (Part I

    Directory of Open Access Journals (Sweden)

    Mario Tarantino

    2007-08-01

    Full Text Available In the History of Medicine, the Acid-Base balance is unusual in that it has undergone constant evolution, not merely and not so much as a result of the progress of knowledge in physiological and physiopathological and clinical fields - which is common to all fields of Medical Science, but rather in relation to its very biochemical foundations, as was demonstrated by P. Stewart’s recent critical review and the reviews of J. Corey and J.A. Kellum, which are still valid today - and this is rather unusual. Although it started centuries ago, the history of the acidbase balance has experienced a slow and difficult evolution, and modern concepts almost exploded a couple of decades into the 20th century. It is therefore with even greater wonder and admiration that we look back on the pioneering intuitions of scholars such as R. Boyle, J.B. van Helmont and A.L. Lavoisier, to mention but a few of the scientists who laid the foundations for current knowledge in this fascinating chapter of physiology and clinical practice that belongs transversally to all medical and clinical disciplines.

  18. Field Balancing in the Real World: Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Bracher, R.K.; Surrett, C.L.

    1999-10-06

    This paper is a follow-up to an earlier paper, Field Balancing in the Real World, which was presented at CSI Reliability Week 1997 in Nashville. Case studies of excessive vibrations on fans at ORNL will be discussed. Except for a few small sections from the earlier paper, this paper is entirely new. The case studies are new. As in the first paper, all fans are rigid-rotor type fans. Normal operation, therefore, is at less than the shaft's first critical speed. The presentation of case studies with root cause problems other than unbalance is a major departure from the first paper. We believe they belong here, since unbalance is suspected most of the time when a fan is vibrating excessively, even when it is not the root cause. In reality, unbalance is the underlying cause of the excess vibration on fans we have fixed at ORNL only about half the time. Furthermore, the analyst's credibility could be called into question upon an unsuccessful attempt at field balancing when underlying causes are later discovered and fixed. A demonstration will follow the case study presentation. The additional tests described in this paper to confirm centrifugal force (probable unbalance) will be performed.

  19. Dissolved carbon leaching from soil is a crucial component of the net ecosystem carbon balance

    DEFF Research Database (Denmark)

    Kindler, Reimo; Siemens, Jan; Kaiser, Klaus;

    2011-01-01

    Estimates of carbon leaching losses from different land use systems are few and their contribution to the net ecosystem carbon balance is uncertain. We investigated leaching of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), and dissolved methane (CH4), at forests, grasslands......, and croplands across Europe. Biogenic contributions to DIC were estimated by means of its d13C signature. Leaching of biogenic DIC was 8.34.9 gm2 yr1 for forests, 24.17.2 gm2 yr1 for grasslands, and 14.64.8 gm2 yr1 for croplands. DOC leaching equalled 3.51.3 gm2 yr1 for forests, 5.32.0 gm2 yr1 for grasslands...... (hydr)oxides. Partial pressures of CO2 in soil air and soil pH determined DIC concentrations and fluxes, but soil solutions were often supersaturated with DIC relative to soil air CO2. Leaching losses of biogenic carbon (DOC plus biogenic DIC) from grasslands equalled 5–98% (median: 22%) of net...

  20. Stand age and climate drive forest carbon balance recovery

    Science.gov (United States)

    Besnard, Simon; Carvalhais, Nuno; Clevers, Jan; Herold, Martin; Jung, Martin; Reichstein, Markus

    2016-04-01

    Forests play an essential role in the terrestrial carbon (C) cycle, especially in the C exchanges between the terrestrial biosphere and the atmosphere. Ecological disturbances and forest management are drivers of forest dynamics and strongly impact the forest C budget. However, there is a lack of knowledge on the exogenous and endogenous factors driving forest C recovery. Our analysis includes 68 forest sites in different climate zones to determine the relative influence of stand age and climate conditions on the forest carbon balance recovery. In this study, we only included forest regrowth after clear-cut stand replacement (e.g. harvest, fire), and afforestation/reforestation processes. We synthesized net ecosystem production (NEP), gross primary production (GPP), ecosystem respiration (Re), the photosynthetic respiratory ratio (GPP to Re ratio), the ecosystem carbon use efficiency (CUE), that is NEP to GPP ratio, and CUEclimax, where GPP is derived from the climate conditions. We implemented a non-linear regression analysis in order to identify the best model representing the C flux patterns with stand age. Furthermore, we showed that each C flux have a non-linear relationship with stand age, annual precipitation (P) and mean annual temperature (MAT), therefore, we proposed to use non-linear transformations of the covariates for C fluxes'estimates. Non-linear stand age and climate models were, therefore, used to establish multiple linear regressions for C flux predictions and for determining the contribution of stand age and climate in forest carbon recovery. Our findings depicted that a coupled stand age-climate model explained 33% (44%, average site), 62% (76%, average site), 56% (71%, average site), 41% (59%, average site), 50% (65%, average site) and 36% (50%, average site) of the variance of annual NEP, GPP, Re, photosynthetic respiratory ratio, CUE and CUEclimax across sites, respectively. In addition, we showed that gross fluxes (e.g. GPP and Re) are

  1. BALANCE

    Science.gov (United States)

    Carmichael, H.

    1953-01-01

    A torsional-type analytical balance designed to arrive at its equilibrium point more quickly than previous balances is described. In order to prevent external heat sources creating air currents inside the balance casing that would reiard the attainment of equilibrium conditions, a relatively thick casing shaped as an inverted U is placed over the load support arms and the balance beam. This casing is of a metal of good thernnal conductivity characteristics, such as copper or aluminum, in order that heat applied to one portion of the balance is quickly conducted to all other sensitive areas, thus effectively preventing the fornnation of air currents caused by unequal heating of the balance.

  2. Fluidized-bed reactor model with generalized particle balances. Part 1. Formulation and solution

    Energy Technology Data Exchange (ETDEWEB)

    Overturf, B.W.; Reklaitis, G.V.

    1983-09-01

    In this first part, a particle balance model is developed for a fluidized-bed gas-solid reactor which accommodates particle distributions dependent on both size and density, as well as populations consisting of multiple solids.

  3. When Forest become carbon sources: Impact of herbivory on carbon balance

    Science.gov (United States)

    Schafer, K. V.; Clark, K. L.; Skowronski, N. S.

    2008-12-01

    Traditionally forests are thought to be carbon sinks and are becoming important trading commodities in the carbon trading markets. However, disturbances such as fire, hurricanes and herbivory can lead to forests being sources rather than sinks of carbon. Here, we investigate the carbon balance of an oak/pine forest in the New Jersey Pine Barrens under herbivory attack in summer 2007. Net primary productivity (NPP) was reduced to ca 70% of previous year NPP (535 g m-2 a-1 in 2006) and canopy net assimilation (AnC), as modeled with the Canopy Conductance Constrained Carbon Assimilation model (4C-A), was reduced to ca 65 % of previous year (1335 g m-2 a-1 in 2006) AnC or ca 1015 g C m-2 a-1. Although the trees were defoliated for only 15 % of the normal annual growing season, the impact amounted to ca 30 % of C accumulation loss when integrated over the year. Overall NPP in 2007 was ca 378 g C m-2 a-1 with 50 % of NPP being allocated to foliage production which constitutes a short term carbon pool. On an ecosystem level net ecosystem exchange amounted to a release of 293 g C m-2 a-1 thus becoming a carbon source over the course of the year rather than being a sink for C. The overall impact of the defoliation spanned 21% of upland forests (320 km2) in the New Jersey Pine Barrens thus representing a significant amount of overall C being emitted back to the atmosphere rather than being accumulated in the biosphere.

  4. Carbon and nutrient use efficiencies optimally balance stoichiometric imbalances

    Science.gov (United States)

    Manzoni, Stefano; Čapek, Petr; Lindahl, Björn; Mooshammer, Maria; Richter, Andreas; Šantrůčková, Hana

    2016-04-01

    Decomposer organisms face large stoichiometric imbalances because their food is generally poor in nutrients compared to the decomposer cellular composition. The presence of excess carbon (C) requires adaptations to utilize nutrients effectively while disposing of or investing excess C. As food composition changes, these adaptations lead to variable C- and nutrient-use efficiencies (defined as the ratios of C and nutrients used for growth over the amounts consumed). For organisms to be ecologically competitive, these changes in efficiencies with resource stoichiometry have to balance advantages and disadvantages in an optimal way. We hypothesize that efficiencies are varied so that community growth rate is optimized along stoichiometric gradients of their resources. Building from previous theories, we predict that maximum growth is achieved when C and nutrients are co-limiting, so that the maximum C-use efficiency is reached, and nutrient release is minimized. This optimality principle is expected to be applicable across terrestrial-aquatic borders, to various elements, and at different trophic levels. While the growth rate maximization hypothesis has been evaluated for consumers and predators, in this contribution we test it for terrestrial and aquatic decomposers degrading resources across wide stoichiometry gradients. The optimality hypothesis predicts constant efficiencies at low substrate C:N and C:P, whereas above a stoichiometric threshold, C-use efficiency declines and nitrogen- and phosphorus-use efficiencies increase up to one. Thus, high resource C:N and C:P lead to low C-use efficiency, but effective retention of nitrogen and phosphorus. Predictions are broadly consistent with efficiency trends in decomposer communities across terrestrial and aquatic ecosystems.

  5. Assessment of climate change impact on SOM balance with the Austrian Carbon Calculator

    Science.gov (United States)

    Franko, Uwe; Gründling, Ralf; Sedy, Katrin; Zethner, Gerhard; Formayer, Herbert

    2015-04-01

    Soil organic matter (SOM) balance depends on climate and climate change due to the impact on SOM turnover conditions as well as on cropping and crop yields. The Austrian Carbon calculator (ACC) is a tool for the comparison of future land use scenarios with the current agriculture in order to identify opportunities to sustain the SOM balance. The ACC can be used in a regional mode as well as in local mode for the assessment of single farm fields. The assessment is based on the concept of Biologic Active Time (BAT). BAT is calculated based on soil data from the Austrian eBod map and climate data for past and future on a 1 km grid. The ACC was implemented for the regions Mühlviertel and Marchfeld. Crop yields are calculated based on statistics from the Austrian agricultural sub regions "Kleinproduktionsgebiet" for the most common crops. The regional scenarios consist of the abundance of crops, the part of nitrogen added as mineral fertilizer and the part of irrigation. The local soil management is calculated based on crop rotations with yields, organic amendments, irrigation and the tillage system (ploughed or not ploughed). The SOM balance is assessed with the reproduction index (REP_IX) that is calculated as the quotient from carbon reproduction (Carbon flux into SOM) and the BAT value. This way REP_IX includes the impact from management as well as from climate. If the future management will not change REP_IX the SOM balance will be the same as well. This methodology helps to adapt the management to future conditions to sustain the current SOM conditions without an absolute assessment if the current SOM state is optimal or not. The regional results of ACC will be made available as thematic maps on the project web site. For local applications farmer can use the tool to analyze their special site conditions and management plans to assess the management options under climate change conditions. The described concept can be improved if reliable information about the

  6. Response of the Amazon carbon balance to the 2010 drought derived with CarbonTracker South America

    NARCIS (Netherlands)

    Laan-Luijkx, van der I.T.; Velde, van der I.R.; Krol, M.C.; Gatti, L.V.; Domingues, L.G.; Correia, C.S.C.; Miller, J.B.; Gloor, M.; Leeuwen, van T.T.; Kaiser, J.W.; Wiedinmyer, C.; Basu, S.; Clerbaux, C.; Peters, W.

    2015-01-01

    Two major droughts in the past decade had large impacts on carbon exchange in the Amazon. Recent analysis of vertical profile measurements of atmospheric CO2 and CO by Gatti et al. (2014) suggests that the 2010 drought turned the normally close-to-neutral annual Amazon carbon balance into a substant

  7. Response of the Amazon carbon balance to the 2010 drought derived with CarbonTracker South America

    NARCIS (Netherlands)

    van der Laan-Luijkx, Ingrid; van der Velde, Ivar; Krol, Maarten; Gatti, Luciana; Miller, John; Gloor, Manuel; van Leeuwen, Thijs; Kaiser, Johannes; Wiedinmyer, Christine; Basu, Sourish; Clerbaux, Cathy; Peters, Wouter

    2015-01-01

    Two major droughts in the past decade had large impacts on carbon exchange in the Amazon. Recent analysis of vertical profile measurements of atmospheric CO2 and CO by Gatti et al. [2014] suggests that the 2010 drought turned the normally close to neutral annual Amazon carbon balance into a substant

  8. "The Balancing Act"--Irish Part-Time Undergraduate Students in Higher Education

    Science.gov (United States)

    Darmody, Merike; Fleming, Bairbre

    2009-01-01

    While the numbers of part-time students has increased in higher education in Ireland, little is known about these students or about how they balance their study and other commitments. Drawing on a larger study on Irish students' experiences in higher education, this article attempts to address this gap in research and reports on Irish part-time…

  9. Amazon old-growth forest wind disturbance and the regional carbon balance

    Science.gov (United States)

    Chambers, J. Q.; Negron Juarez, R. I.; Marra, D. M.; Roberts, D. A.; Hurtt, G. C.; Lima, A.; Higuchi, N.

    2010-12-01

    Estimating the carbon balance of a landscape is challenging. A key problem is determining whether or not measurements made in plots are representative of the carbon state of a larger region. A key parameter for calculating landscape carbon balance is the return frequency of episodic disturbances. If disturbances are clustered and occur more frequently than the time required for biomass recovery, a spatial mixture of patches in different stages of recovery occurs. Under these shifting steady-state mosaic conditions, quantifying the mean state of ecosystem attributes such as carbon balance or tree species diversity is difficult. In this study, satellite remote sensing (Landsat) was coupled with field investigations to create ~25 year landscape-scale disturbance chronosequence for old-growth forest in the Central Amazon. The detected disturbances were caused by strong storms which resulted in tree mortality events ranging from small clusters of 7-10 downed trees, to large contiguous blowdowns larger than 30 ha in size. Using the chronosequence, a cumulative probability distribution function was developed, which followed a power law, and was used to parameterize a forest carbon balance model. Results demonstrate that for power law exponents less than about 2.0, the spatial scale at which forest carbon balance establishes is much larger than generally expected. Ultimately, an increase in wind disturbance frequency and/or intensity with a warming climate has the potential to cause a net loss of carbon from Amazon forests to the atmosphere.

  10. GCM characteristics explain the majority of uncertainty in projected 21st century terrestrial ecosystem carbon balance

    Directory of Open Access Journals (Sweden)

    A. Ahlström

    2012-10-01

    Full Text Available One of the largest sources of uncertainties in modelling of the future global climate is the response of the terrestrial carbon cycle. Studies have shown that it is likely that the extant land sink of carbon will weaken in a warming climate. Should this happen, a~larger portion of the annual carbon dioxide emissions will remain in the atmosphere, and further increase the global warming, which in turn may further weaken the land sink. We investigate the potential sensitivity of global terrestrial ecosystem carbon balance to differences in future climate simulated by four general circulation models (GCMs under three different CO2 concentration scenarios. We find that the response in simulated carbon balance is more influenced by GCMs than CO2 concentration scenarios. Singular Value Decomposition (SVD analysis of sea surface temperatures (SSTs reveals differences in the GCMs SST variability leading to decreased tropical ecosystem productivity in two out of four GCMs. We extract parameters describing GCM characteristics by parameterizing a statistical replacement model mimicking the simulated carbon balance results. By sampling two GCM-specific parameters and global temperatures we create 60 new "artificial" GCMs and investigate the extent to which the GCM characteristics may explain the uncertainty in global carbon balance under future radiative forcing. Our analysis suggests that differences among GCMs in the representation of SST variability and ENSO and its effect on precipitation and temperature patterns explains the majority of the uncertainty in the future evolution of global terrestrial ecosystem carbon.

  11. Carbon mass-balance modeling and carbon isotope exchange processes in the Curonian Lagoon

    Science.gov (United States)

    Barisevičiūtė, Rūta; Žilius, Mindaugas; Ertürk, Ali; Petkuvienė, Jolita

    2016-04-01

    The Curonian lagoon one of the largest coastal lagoons in Europe is located in the southeastern part of the Baltic Sea and lies along the Baltic coast of Lithuania and the Kaliningrad region of Russia. It is influenced by a discharge of the Nemunas and other smaller rivers and saline water of the Baltic Sea. The narrow (width 0.4 km, deep 8-14 m) Klaipėda Strait is the only way for fresh water run-off and brackish water intrusions. This research is focused on carbon isotope fractionations related with air - water exchange, primary production and organic carbon sedimentation, mineralization and uptake from both marine and terrestrial sources.

  12. BALANCING ON THE BORDERLINE OF EARLY AFFECT-CONFUSION - PART 2 OF A CASE STUDY TRILOGY

    Directory of Open Access Journals (Sweden)

    Richard G. Erskine

    2013-05-01

    Full Text Available Part 2 of a case study trilogy on early affect-confusion describes the psychotherapy relationship between an angry/helpless client and the psychotherapist’s skill in balancing the “borderline” between behavioral management and affect attunement, historical inquiry and normalization, validation and shame. The therapeutic use of bifurcated questions and juxtaposition reactions is illustrated.

  13. Importance of vegetation distribution for future carbon balance

    Science.gov (United States)

    Ahlström, A.; Xia, J.; Arneth, A.; Luo, Y.; Smith, B.

    2015-12-01

    Projections of future terrestrial carbon uptake vary greatly between simulations. Net primary production (NPP), wild fires, vegetation dynamics (including biome shifts) and soil decomposition constitute the main processes governing the response of the terrestrial carbon cycle in a changing climate. While primary production and soil respiration are relatively well studied and implemented in all global ecosystem models used to project the future land sink of CO2, vegetation dynamics are less studied and not always represented in global models. Here we used a detailed second generation dynamic global vegetation model with advanced representation of vegetation growth and mortality and the associated turnover and proven skill in predicting vegetation distribution and succession. We apply an emulator that describes the carbon flows and pools exactly as in simulations with the full model. The emulator simulates ecosystem dynamics in response to 13 different climate or Earth system model simulations from the CMIP5 ensemble under RCP8.5 radiative forcing at year 2085. We exchanged carbon cycle processes between these 13 simulations and investigate the changes predicted by the emulator. This method allowed us to partition the entire ensemble carbon uptake uncertainty into individual processes. We found that NPP, vegetation dynamics (including biome shifts, wild fires and mortality) and soil decomposition rates explained 49%, 17% and 33% respectively of uncertainties in modeled global C-uptake. Uncertainty due to vegetation dynamics was further partitioned into stand-clearing disturbances (16%), wild fires (0%), stand dynamics (7%), reproduction (10%) and biome shifts (67%) globally. We conclude that while NPP and soil decomposition rates jointly account for 83% of future climate induced C-uptake uncertainties, vegetation turnover and structure, dominated by shifts in vegetation distribution, represent a significant fraction globally and regionally (tropical forests: 40

  14. Permafrost and surface energy balance of a polygonal tundra site in northern Siberia – Part 1: Spring to fall

    Directory of Open Access Journals (Sweden)

    M. Langer

    2010-07-01

    Full Text Available Permafrost thawing is essentially determined by the surface energy balance, which potentially triggers the activation of a massive carbon source, if previously frozen organic soils are exposed to microbial decomposition. In this article, we present the first part of a comprehensive annual surface energy balance study performed at a polygonal tundra landscape in northeast Siberia, realized between spring 2007 and winter 2009. This part of the study focuses on the half year period from April to September 2007–2008, during which the surface energy balance is obtained from independent measurements of the radiation budget, the turbulent heat fluxes and the ground heat flux at several sites. The short-wave radiation is the dominant factor in the surface energy balance during the entire observation period. About 50% of the available net radiation is consumed by latent heat flux, while the sensible and the ground heat flux are both on the order of 20 to 30%. The ground heat flux is mainly consumed by active layer thawing, where 60% of soil energy storage are attributed to. The remainder is used for soil warming down to a depth of 15 m. The controlling factors for the surface energy partitioning are in particular the snow cover, the cloud cover and the soil temperature gradient. Significant surface temperature differences of the heterogeneous landscape indicate spatial variabilities of sensible and latent heat fluxes, which are verified by measurements at different locations. However, differences in the partition between sensible and latent heat flux for the different sites only exist during conditions of high radiative forcing, which only occur occasionally.

  15. Historic simulation of net ecosystem carbon balance for the Great Dismal Swamp

    Science.gov (United States)

    Sleeter, Rachel

    2017-01-01

    Estimating ecosystem carbon (C) balance relative to natural disturbances and land management strengthens our understanding of the benefits and tradeoffs of carbon sequestration. We conducted a historic model simulation of net ecosystem C balance in the Great Dismal Swamp, VA. for the 30-year time period of 1985-2015. The historic simulation of annual carbon flux was calculated with the Land Use and Carbon Scenario Simulator (LUCAS) model. The LUCAS model utilizes a state-and-transition simulation model coupled with a carbon stock-flow accounting model to estimate net ecosystem C balance, and long term sequestration rates under various ecological conditions and management strategies. The historic model simulation uses age-structured forest growth curves for four forest species, C stock and flow rates for 8 pools and 14 fluxes, and known data for disturbance and management. The annualized results of C biomass are provided in this data release in the following categories: Growth, Heterotrophic Respiration (Rh), Net Ecosystem Production (NEP), Net Biome Production (NBP), Below-ground Biomass (BGB) Stock, Above-ground Biomass (AGB) Stock, AGB Carbon Loss from Fire, BGB Carbon Loss from Fire, Deadwood Carbon Loss from Management, and Total Carbon Loss. The table also includes the area (annually) of each forest type in hectares: Atlantic white cedar Area (hectares); Cypress-gum Area (hectares); Maple-gum Area (hectares); Pond pine Area (hectares). Net ecosystem production for the Great Dismal Swamp (~ 54,000 ha), from 1985 to 2015 was estimated to be a net sink of 0.97 Tg C. When the hurricane and six historic fire events were modeled, the Great Dismal Swamp became a net source of 0.89 Tg C. The cumulative above and belowground C loss estimated from the South One in 2008 and Lateral West fire in 2011 totaled 1.70 Tg C, while management activities removed an additional 0.01 Tg C. The C loss in below-ground biomass alone totaled 1.38 Tg C, with the balance (0.31 Tg C

  16. An energy balance model of carbon's effect on climate change

    CERN Document Server

    Benney, Lucas

    2015-01-01

    Due to climate change, the interest of studying our climatic system using mathematical modeling has become tremendous in recent years. One well-known model is Budyko's system, which represents the coupled evolution of two variables, the ice-line and the average earth surface temperature. The system depends on natural parameters, such as the earth albedo, and the amount A of carbon in the atmosphere. We introduce a 3-dimensional extension of this model in which we regard A as the third coupled variable of the system. We analyze the phase space and dependence on parameters, looking for Hopf bifurcations and the birth of cycling behavior. We interpret the cycles as climatic oscillations triggered by the sensitivity in our regulation of carbon emissions at extreme temperatures.

  17. Carbon balance and water use efficiency of frequently cut Lolium perenne L. swards at elevated carbon dioxide

    NARCIS (Netherlands)

    Schapendonk, A.H.C.M.; Dijkstra, P.; Groenwold, J.; Pot, C.S.; Geijn, van de S.C.

    1997-01-01

    The impact of doubled atmospheric [CO2] on the carbon balance of regularly cut Lolium perenne L. swards was studied for two years under semi-field conditions in the Wageningen Rhizolab. CO2 and H2O vapour exchange rates of the swards were measured continuously for two years in transparent enclosures

  18. Carbon balance of renovated grasslands: input- or output-driven?

    Science.gov (United States)

    Choncubhair, Órlaith Ní; Osborne, Bruce; Lanigan, Gary

    2015-04-01

    Temperate grasslands constitute over 30% of the Earth's naturally-occurring biomes and make an important contribution towards the partial mitigation of anthropogenic greenhouse gas emissions by terrestrial ecosystems. In permanent temperate grasslands, biomass production and sward quality can deteriorate over time and periodic renovation activities, involving soil tillage and reseeding, are commonly carried out to halt this decline. Long-term cultivation of agricultural land has been associated with soil aggregate degradation and reduced soil carbon storage. However, the impact of these single tillage disturbances on C cycling in grasslands is less clear. This study evaluated gaseous and dissolved organic carbon (DOC) losses following a single tillage event by subjecting grassland lysimeters with contrasting soil drainage characteristics to simulated conventional inversion or minimum tillage. Field-scale CO2 emissions after conventional tillage were also quantified and empirically modelled over short- and medium-term timeframes to delineate the ecosystem response to environmental variables. Soil moisture was the limiting determinant of ecosystem carbon release following conventional tillage. Freshly-tilled soils were associated with reduced water retention and increased sensitivity to soil moisture, which was particularly pronounced following rewetting events. Significantly elevated but ephemeral CO2 effluxes were detected in the hours following inversion ploughing, however tillage disturbance did not generate significantly enhanced C emission rates in the medium term. Equally, DOC losses were not significantly amplified by conventional tillage compared with conservative minimum tillage and were predominantly controlled by soil drainage across tillage regimes. Our results suggest that a net ecosystem source of 120 to 210 g C m-2 over an approximately two-month period was most likely a consequence of reduced productivity and C input rather than enhanced soil CO2

  19. Photosynthesis and carbon balance of a Sahelian fallow savanna

    NARCIS (Netherlands)

    Hanan, N.P.; Kabat, P.; Dolman, A.J.; Elbers, J.A.

    1998-01-01

    Eddy-covariance measurements of CO2 exchange above a Sahelian savanna consisting of small shrubs over a near-continuous herb layer were made during the HAPEX-Sahel experiment in Niger, West Africa. The measurements were made near-continuously during an 8-week period, covering the main part of the ra

  20. Carbon balance of an old hemi-boreal pine forest in Southern Estonia determined by different methods

    Science.gov (United States)

    Soosaar, Kaido; Repp, Kalev; Lõhmus, Krista; Uri, Veiko; Rannik, Kaire; Krasnova, Alisa; Ostonen, Ivika; Kukumägi, Mai; Maddison, Martin; Mander, Ülo

    2016-04-01

    The Soontaga Forest Station is located in hemi-boreal 200-years old pine forest (South Estonia; 58o01'N 26o04'E) with a second layer of spruce. The station has the instrumentation to assess the exchange of carbon dioxide (net ecosystem exchange, NEE), soil respiration, tree biomass (above and below ground biomass) and different environmental and meteorological parameters. In this study we quantified carbon balance by analyzing eddy-covariance CO2 flux data (carbon exchange) vs chamber-based measurements (ecosystem respiration) and CO2assimilation (soil and biomass). The annual NEE in this mature coniferous forest was -2.3 t C ha yr-1, showing a clear diurnal and seasonal trend. During the daytime in summer the forest sequestered CO2, while during the night and late night CO2 emitted from the ecosystem to the atmosphere. Within the growing period, the sequestration of CO2 by plants was greater than soil respiration. Thus, the ecosystem sequestered carbon. Most of the carbon is bound in tree biomass (above and below ground biomass) but as well into soil, while the sequestration in soil increases with stand age. In addition, the biomass of understory, especially belowground litter, is playing essential part in carbon input. A modelling approach of long-term C budget in the Soontaga pine forest is presented.

  1. Carbon balance of an intensively grazed permanent grassland in southern Belgium

    Science.gov (United States)

    Gourlez de la Motte, Louis; Jérôme, Elisabeth; Mamadou, Ossénatou; Beckers, Yves; Bodson, Bernard; Heineisch, Bernard; Aubinet, Marc

    2016-04-01

    Grasslands are an important component of the global carbon balance but their carbon storage potential is still highly uncertain. Especially, the impact of weather variability and management practices on grassland carbon budgets need to be assessed. This study investigates the carbon balance of an intensively managed permanent grassland (Dorinne Terrestrial Observatory (DTO)) and its uncertainties by combining 5-years of eddy covariance measurements and other organic carbon exchanges estimates. The specificities of this study lie in: (i) the age of the pasture, which has probably been established since more than one century; (ii) the intensive character of the management with a mean grazing pressure larger than 2 livestock unit ha-1 and stocking cycle including stocking and rest periods, (iii) the livestock production system, typical of Wallonia, farming intensively Belgian Blue breed of cattle in order to produce meat. The results showed that, despite the high stocking rate and the old age of the pasture and the high stocking rate, the site acted as a relatively stable carbon sink from year to year with a 5-year average Net Biome Productivity of ‒173 [‒128 ‒203] g C m-2 yr-1. The carbon sink behavior of the pasture was directly increased by management practices through food complementation and organic fertilization and indirectly by mineral fertilization. The relatively low carbon budget inter-annual variability could be explained both by: (i) grazing management of the farmer that regulated Growth Primary Productivity by adapting the stocking rate to the Leaf Area Index which itself depends on weather conditions, (ii) carbon imports through food complements only when grass regrowth was not sufficient to feed the cattle. The results suggest that management practices that tend to optimize forage availability for meat production could contribute to maintaining a carbon sink. Keywords : grassland, carbon budget, carbon dioxide flux, management, eddy covariance

  2. Carbon in the Former Soviet Union: The Current Balance

    Science.gov (United States)

    Woodwell, G. M.; Stone, T. A.; Houghton, R. A.

    1997-01-01

    senior scientist (mensuration) for the Soviet Committee on Forests, now a scholar at the International Institute of Applied Systems Analysis (IIASA), Vienna, has provided abundant contributions from the data available to him and from his experience. Forest stand carbon is concentrated in the Russian Far East (i.e. Primorski Kray), Central-Southern Siberia and European Russia But, soil carbon can be 10 times forest stand C. Our efforts in mapping the area and changes in area (as well as the internal structure) of forests have made major contributions to our joint understanding of the scale and status of these forests. To realize the importance of this contribution one needs only to recognize that any large scale Soviet-era maps of the area did not include latitude and longitude. Even today, there is great reluctance to provide these data, the basis of any GIS.

  3. Oral calcium carbonate affects calcium but not phosphorus balance in stage 3-4 chronic kidney disease.

    Science.gov (United States)

    Hill, Kathleen M; Martin, Berdine R; Wastney, Meryl E; McCabe, George P; Moe, Sharon M; Weaver, Connie M; Peacock, Munro

    2013-05-01

    Patients with chronic kidney disease (CKD) are given calcium carbonate to bind dietary phosphorus, reduce phosphorus retention, and prevent negative calcium balance; however, data are limited on calcium and phosphorus balance during CKD to support this. Here, we studied eight patients with stage 3 or 4 CKD (mean estimated glomerular filtration rate 36 ml/min) who received a controlled diet with or without a calcium carbonate supplement (1500 mg/day calcium) during two 3-week balance periods in a randomized placebo-controlled cross-over design. All feces and urine were collected during weeks 2 and 3 of each balance period and fasting blood, and urine was collected at baseline and at the end of each week. Calcium kinetics were determined using oral and intravenous (45)calcium. Patients were found to be in neutral calcium and phosphorus balance while on the placebo. Calcium carbonate supplementation produced positive calcium balance, did not affect phosphorus balance, and produced only a modest reduction in urine phosphorus excretion compared with placebo. Calcium kinetics demonstrated positive net bone balance but less than overall calcium balance, suggesting soft-tissue deposition. Fasting blood and urine biochemistries of calcium and phosphate homeostasis were unaffected by calcium carbonate. Thus, the positive calcium balance produced by calcium carbonate treatment within 3 weeks cautions against its use as a phosphate binder in patients with stage 3 or 4 CKD, if these findings can be extrapolated to long-term therapy.

  4. Estimation of Carbon Balance in Young and Mature Stands of Japanese Cedar (Cryptomeria Japonica) Plantation

    Science.gov (United States)

    Lee, M.; Sode, N.; Koizumi, H.

    2006-12-01

    Two-thirds of Japan is covered by forests, and Japanese cedar (Cryptomeria japonica D. Don) plantations occupy approximately 45% of the plantation areas or 20% of total forested area in Japan. Since the 1950s, cedar plantation has been encouraged and managed for timber production. Therefore, it is important to study quantitatively and synthetically the balance of carbon in cedar plantation ecosystems according to forest development. The ecological process-based approach provides a detailed assessment of belowground compartment as one of the major compartment of carbon balance. Carbon net balance (NEP: net ecosystem production) in ecosystems by this approach is determined by the balance between net primary production (NPP) of vegetation and heterotrophic respiration (HR) of soil (NEP= NPP-HR). HR is the difference between total soil respiration (SR) and root respiration (RR) (HR= SR-RR). To estimate the NPP, we used to biometric method by allometric relationships and litter traps. To estimate the SR, we used a chamber system with automatic open and closing for measuring continuous CO2 efflux from soil surface based on an open-flow method (AOCC) and a portable system for measuring leaf photosynthesis attached to a soil chamber (LI-6400). Our object is to examine balance of carbon in ca. 7 y old (young) and 45 y old (mature) stands of Japanese cedar. Our goal of this study is to investigate carbon cycling on a regional scale using ecological process, remote sensing, and climate observation and modeling analysis as part of the 21st COE program {Satellite Ecology}. This presents the initial results obtained by a process-based measurement since 2004. The study region refers to a cool temperate zone, Asia monsoon climate (36° 08'N, 137° 22'E). In the mature stand, Japanese cedar plantation located in about 10km east of Takayama city, central Japan. The ecological-process research plot was established on the middle of a slope (30m×50m) in November 2004. The slope

  5. Who's got the balance? A study of satisfaction with the work-family balance among part-time service sector employees in five western European countries

    NARCIS (Netherlands)

    Beham, Barbara; Prag, Patrick; Drobnic, Sonja

    2012-01-01

    Working part-time is frequently considered a viable strategy for employees to better combine work and non-work responsibilities. The present study examines differences in satisfaction with work-family balance (SWFB) among professional and non-professional part-time service sector employees in five w

  6. Response of the Amazon Carbon Balance to the 2010 Drought Derived with CarbonTracker South America

    Science.gov (United States)

    van der Laan-Luijkx, I. T.; van der Velde, I. R.; Krol, M. C.; Gatti, L. V.; Domingues, L. G.; Correia, C. S. C.; Miller, J. B.; Gloor, M.; van Leeuwen, T. T.; W Kaiser, J.; Wiedinmyer, C.; Basu, S.; Clerbaux, C.; Peters, W.

    2015-12-01

    Two major droughts in the past decade had large impacts on carbon exchange in the Amazon. Recent analysis of vertical profile measurements of atmospheric CO2 and CO by Gatti et al. [Nature, 506(7486), 76-80, 2014] suggests that the 2010 drought turned the normally close-to-neutral annual Amazon carbon balance into a substantial source of nearly 0.5 PgC/yr, revealing a strong drought response. In this study, we revisit this hypothesis and interpret not only the same CO2/CO vertical profile measurements, but also additional constraints on carbon exchange such as satellite observations of CO, burned area, and fire hotspots. The results from our CarbonTracker South America data assimilation system suggest that carbon uptake by vegetation was indeed reduced in 2010, but that the magnitude of the decrease strongly depends on the estimated 2010 and 2011 biomass burning emissions. We have used fire products based on burned area (GFED4), satellite-observed CO columns (IASI), fire radiative power (GFASv1) and fire hotspots (FINNv1), and found an increase in biomass burning emissions in 2010 compared to 2011 of 0.16 to 0.24 PgC/yr. We derived a decrease of biospheric uptake ranging from 0.08 to 0.26 PgC/yr, with the range determined from a set of alternative inversions using different biomass burning estimates. Our numerical analysis of the 2010 Amazon drought results in a total reduction of carbon uptake of 0.24 to 0.50 PgC/yr and turns the balance from carbon sink to source. Our findings support the suggestion that the hydrological cycle will be an important driver of future changes in Amazonian carbon exchange.

  7. Influence of bark beetles outbreaks on the carbon balance of western United States forests

    Science.gov (United States)

    Ghimire, B.; Williams, C. A.; Collatz, G. J.; Masek, J. G.

    2011-12-01

    Recently bark beetle outbreaks have been increasing in western United States forests due to increases in temperatures and prolonged occurrence of droughts. Bark beetle outbreaks transfer carbon from the live photosynthesizing pools to the dead respiring pool where carbon slowly decomposes into the atmosphere causing landscapes to change from a net sink to source of carbon. Previous studies have usually been conducted at small localized areas, focused only on one or two bark beetle types or encompass a single outbreak event. The literature largely ignores the influence of bark beetle mortality on carbon balance at both local and regional scales by focusing on multiple bark beetles types and events. This study uses a combination of the Carnegie Ames Stanford Approach (CASA) carbon cycle model driven by remotely sensed biophysical observations, Forest Inventory and Analysis (FIA) derived post-disturbance biomass regeneration trajectories, and mortality rates obtained from Aerial Detection Survey (ADS) insect outbreak polygons. The synthesis of the carbon cycle based modeling approach and different data products results in characteristic carbon trajectories for Net Ecosystem Productivity (NEP), Net Primary Productivity (NPP) and heterotrophic respiration associated with insect outbreaks. This study demonstrates that bark beetle events change landscapes from a sink to source of carbon at a local scale but at a larger regional level the influence of bark beetle outbreaks are not prominent compared to other disturbance agents.

  8. Carbon dioxide and the stomatal control of water balance and photosynthesis in higher plants

    Energy Technology Data Exchange (ETDEWEB)

    Taiz, L.; Zeiger, E.; Mawson, B. T.; Cornish, K.; Radin, J. W.; Turcotte, E. L.; Hercovitz, S.; Tallman, G.; Karlsson, P. E.; Bogomolni, R. A.; Talbott, L. D.; Srivastava, A.

    1992-01-01

    Research continued into the investigation of the effects of carbon dioxide on stomatal control of water balance and photosynthesis in higher plants. Topics discussed this period include a method of isolating a sufficient number of guard cell chloroplasts for biochemical studies by mechanical isolation of epidermal peels; the measurement of stomatal apertures with a digital image analysis system; development of a high performance liquid chromatography method for quantification of metabolites in guard cells; and genetic control of stomatal movements in Pima cotton. (CBS)

  9. Static and Dynamic Analysis of a Pump Impeller with a Balancing Device Part I: Static Analysis

    Directory of Open Access Journals (Sweden)

    Kundera C.

    2014-08-01

    Full Text Available This part of the work presents the design and static analysis of an impeller for a single-stage pump. The impeller is directly connected with a balancing device. The impeller needs to have a properly designed system of longitudinal and lateral clearances on both sides. With the simplifying assumptions concerning the flow and distribution of pressure in the longitudinal and lateral clearances, the static analysis involved deriving relationships between the impeller geometry and the basic performance parameters of the pump. A numerical example was used to show the calculation procedure of static characteristics for the predetermined parameters

  10. Century-scale patterns and trends of global pyrogenic carbon emissions and fire influences on terrestrial carbon balance

    Science.gov (United States)

    Yang, Jia; Tian, Hanqin; Tao, Bo; Ren, Wei; Lu, Chaoqun; Pan, Shufen; Wang, Yuhang; Liu, Yongqiang

    2015-09-01

    Fires have consumed a large amount of terrestrial organic carbon and significantly influenced terrestrial ecosystems and the physical climate system over the past century. Although biomass burning has been widely investigated at a global level in recent decades via satellite observations, less work has been conducted to examine the century-scale changes in global fire regimes and fire influences on the terrestrial carbon balance. In this study, we investigated global pyrogenic carbon emissions and fire influences on the terrestrial carbon fluxes from 1901 to 2010 by using a process-based land ecosystem model. Our results show a significant declining trend in global pyrogenic carbon emissions between the early 20th century and the mid-1980s but a significant upward trend between the mid-1980s and the 2000s as a result of more frequent fires in ecosystems with high carbon storage, such as peatlands and tropical forests. Over the past 110 years, average pyrogenic carbon emissions were estimated to be 2.43 Pg C yr-1 (1 Pg = 1015 g), and global average combustion rate (defined as carbon emissions per unit area burned) was 537.85 g C m-2 burned area. Due to the impacts of fires, the net primary productivity and carbon sink of global terrestrial ecosystems were reduced by 4.14 Pg C yr-1 and 0.57 Pg C yr-1, respectively. Our study suggests that special attention should be paid to fire activities in the peatlands and tropical forests in the future. Practical management strategies, such as minimizing forest logging and reducing the rate of cropland expansion in the humid regions, are in need to reduce fire risk and mitigate fire-induced greenhouse gases emissions.

  11. Carbon and greenhouse gas balance of a temperate pine afforestation chronosequence

    Science.gov (United States)

    Peichl, Matthias; Arain, Altaf; Moore, Tim R.; Brodeur, Jason J.; Khomik, Myroslava; Ullah, Sami; Trant, Janelle; Thorne, Robin

    2013-04-01

    We determined the carbon (C) and greenhouse gas (GHG) balance for an age-sequence of four (7, 20, 35, and 70 years old) afforested white pine (Pinus strobus L.) forests in southern Ontario, Canada. The annual net ecosystem production (NEP) derived from biometric and eddy-covariance (EC) data was combined with estimates of the dissolved organic carbon (DOC) export to obtain the annual net ecosystem carbon balance (NECB). Static chamber measurements of methane (CH4) and nitrous oxide (N2O) fluxes were conducted throughout the snow free periods. The average contribution of DOC export to the NECB decreased from 8% at the 7-year old stand to <1% at the three older stands. The combined contribution from exchanges of CH4 and N2O to the global warming potential (GWP) was estimated at 9% in the 7-year old stand and at 5% in the mature 70-year old stand indicating a significant contribution to the GHG balance of temperate pine forests in early and late development stages. In the two middle-aged stands however, this contribution was <1% and integrated over the entire succession period, the GWP of these forests was driven by the CO2 exchange. Furthermore, our results indicate a large potential for net C sequestration through afforestation of marginal agricultural land ranging between 130 t C ha-1 for low-productive stands to 250 t C ha-1 in high productive pine stands over a period of 70 years.

  12. Changes in carbon balance after insect disturbance in Western U.S. forests

    Science.gov (United States)

    Trahan, N. A.; Moore, D. J. P.; Wilkes, P.; Quaife, T.; Desai, A. R.; Negron, J.; Stephens, B. B.; Elder, K.; Brayden, B. H.; Monson, R. K.

    2012-04-01

    Large scale tree mortality changes the balance between gross primary productivity (GPP) and total ecosystem respiration (TER). Mountain pine beetles (Dendroctonus ponderosae) have infested more than 86 million hectares of forest in the U.S.A. since 2000, leading to extensive tree mortality which is predicted to have important carbon, water and energy balance feedbacks on the Earth system. Current projections, based on models linked to changes in live tree stocks, suggest a sharp and prolonged transition of forest ecosystems from carbon sinks to significant carbon sources. We compared 9-year records of GPP and TER fluxes, and parallel disturbance chronosequences in two high elevation lodgepole pine forests in Colorado U.S.A., one impacted by the beetle (Fraser Experimental Forest) and a forest free of the outbreak (Niwot Ridge). We show that on a decadal scale the impact of this tree mortality on the carbon cycle is significantly less pronounced than these predictions because of a sustained suppression of respiration after mortality. We detect no increase in respiration after mortality from scales of several square meters up to an 84 km2 valley; rather we find a decline in both GPP and respiration suggesting a dampening of the carbon cycle. The sharp decline in respiration with GPP reflects the loss of autotrophic respiration and rhizodeposition occurring with tree mortality. We find a partial and transitory recovery of respiration 5-6 years after mortality, de-coupling respiration from concurrent GPP and associated with increased incorporation of C into soil organic matter. At the same time, trees that survive beetle outbreak undergo competitive release, allocating more carbon to growth in response to enhanced resource availability. In contrast to other disturbances like fire or logging, the impact of tree mortality caused by these biotic disturbances in Western North America is likely to have a subtle, long lasting impact on the carbon cycle which will require

  13. CO2 exchange and Carbon balance in two grassland sites on eutrophic drained peat soils

    Directory of Open Access Journals (Sweden)

    F. Möller

    2007-05-01

    Full Text Available In this study we investigated the role of intensive and extensive dairy farm practices on CO2 exchange and the carbon balance of peatlands by means of eddy covariance (EC measurements. Year long EC measurements were made in two adjacent farm sites on peat soil in the western part of the Netherlands. One site (Stein is a new meadow bird reserve and is managed predominantly by mowing in June and August. The second site (Oukoop is an intensive dairy farm. Minimum ecosystem flux of the grass sward (range −2 to −34 μmol CO2 m−2 s−1 showed a close and similar linear relationship with Leaf Area Index (LAI; range 1 to 5 except in maturing hay meadows, where minimum ecosystem flux did not decrease further. Apparent quantum yield varied between −0.02 and −0.08 (mean −0.045 μmol CO2 μmol−1 photons at both sites and was significantly correlated with LAI during the growth season. Ecosystem Respiration at 10°C (R10 calculated from the year round data set was 3.47 μmol CO2 m−2 s−1 at Stein and 3.64 μmol CO2 m−2 s−1 at Oukoop. Both sites were a source of carbon in winter and a sink during summer, with net ecosystem exchange varying between 50 to 100 mmol CO2m−2 d−1 in winter to below −400 mmol CO2 m−2 d−1 in summer. Periodically both sites became a source after mowing. Net annual ecosystem exchange (NEE for Stein was −8.4 g C m−2 a−1 and for Oukoop 122.4 g C m−2 a−1, the difference between the sites was mainly due a difference in GEP (101 g C m−2 a−1. However when biomass removal, manure applications and estimates of methane emissions are taken into account, both eutrophic peat meadows are a strong source for C ((462 g C m−2 a−1 and 465 g C m−2 a−1 at Stein and Oukoop, respectively.

  14. Detecting Disturbance and its Impact on Ecosystem Carbon Balance from Global to Regional Scales

    Science.gov (United States)

    Ballantyne, A.; Jacobson, A. R.; Anderegg, W.; Poulter, B.; Cooper, L. A.; Smith, W. K.; Miller, J. B.

    2015-12-01

    One of the most vital ecosystem services currently provided by the terrestrial biosphere is the removal of approximately one quarter of the anthropogenic CO2 emitted to the atmosphere. However, as patterns of temperature and precipitation change so is the frequency and intensity of ecosystem disturbance. Despite evidence that ecosystem disturbance regimes have shifted leading to widespread forest mortality, the net effect of disturbance on the carbon (C) balance of forest ecosystems remains uncertain. We will use satellite and atmospheric observations to deconvolve net carbon exchange (NEE) into its component fluxes of gross primary productivity and total respiration (e.g. NEE= GPP - R) at global to regional scales. At the global scale we find that NEE has increased over the last 50 years and appears to have accelerated as a result of diminished R over the last 15 years. However the variance in global NEE has also increased perhaps due to inter-annual variability in R, especially within semi-arid ecosystems. These global trends are not necessarily consistent with regional patterns in the net carbon balance, especially across the western US. Atmospheric mass balance suggests that ecosystems of North America have shifted from a net C sink to a net C source. While prolonged drought across the Western US has likely caused this shift in continental scale NEE, attributing this shift in the net C balance to any one mechanism of disturbance (e.g. drought, insect infestation, and fire) or their interactions is challenging. Lastly, we will evaluate existing observing networks, such as NOAA/ESRL and Ameriflux, and how they can be combined with nascent networks, such as NEON, EarthNetworks, and OCO-2, to identify regional disturbance processes that may be causing increasing variance in the global C cycle.

  15. Toward a consistency cross-check of eddy covariance flux-based and biometric estimates of ecosystem carbon balance

    NARCIS (Netherlands)

    Luyssaert, S.; Reichstein, M.; Schulze, E.D.; Janssens, I.A.; Law, B.E.; Papale, D.; Dragoni, D.; Goulden, M.L.; Granier, A.; Kutch, W.L.; Linder, S.; Matteucci, G.; Moors, E.J.; Munger, J.W.; Pilegaard, K.; Saunders, M.; Falge, E.M.

    2009-01-01

    Quantification of an ecosystem's carbon balance and its components is pivotal for understanding both ecosystem functioning and global cycling. Several methods are being applied in parallel to estimate the different components of the CO2 balance. However, different methods are subject to different so

  16. CO2 and Carbon Balance of an Intensively Grazed Temperate Pasture: Response to Cultivation

    Science.gov (United States)

    Rutledge, S.; Mudge, P. L.; Wallace, D.; Campbell, D.; Wall, A.; Hosking, C. L.; Schipper, L. A.

    2012-12-01

    Recent soil resampling studies have shown that soils on flat land used for intensive dairy farming in New Zealand have lost large amounts of carbon (~1 t C ha-1y-1) over the past few decades, and the causes of these losses are poorly understood. One of the management practices potentially contributing to the C losses from these dairy soils is the periodic cultivation commonly associated with pasture renewal or the rotation through summer or winter crops. Here we report the results of three experiments aimed at quantifying the effect of cultivation as part of pasture renewal on the CO2 and C balances of permanent pastures. In the first experiment, the net ecosystem CO2 exchange (NEE) of an intensively grazed dairy pasture was measured before, during and after cultivation using eddy covariance (EC) from 2008 to 2011 at a dairy farm in the Waikato region on the North Island of New Zealand. The net ecosystem carbon balance (NECB) was determined by combining NEE data with measurements and estimates of other C imports (feed) and C exports (milk, methane, silage and leaching). The other two experiments took place on the same farm and monitored two different cultivation events in 2008. We made chamber measurements of soil CO2 losses between spraying and seedling emergence. One of the cultivations took place in summer 2008 during a drought, whereas the other took place in spring 2008 when soil water was not limiting. For the first two years of experiment 1 the site was under permanent pasture and it was a sink for both CO2 (1.6 and 2.3 t C ha-1y-1 for 2008 and 2009, respectively) and C (0.59 and 0.90 t C ha-1y-1 for 2008 and 2009, respectively), despite a severe drought in summer 2008 which had led to a loss of approximately 1.1 t C ha-1 as CO2 over the three summer months. Pasture renewal took place in March 2010 and CO2 losses during this event were approximately 1.7 t C ha-1. However, the site seemed to recover quickly and was a sink of CO2 at an annual time scale of

  17. Carbon balance of a fertile forestry-drained peatland in southern Finland

    Science.gov (United States)

    Lohila, Annalea; Korkiakoski, Mika; Tuovinen, Juha-Pekka; Minkkinen, Kari; Penttilä, Timo; Ojanen, Paavo; Launiainen, Samuli; Laurila, Tuomas

    2016-04-01

    Forestry on peatlands is a significant land use form and has been economically important during the last decades particularly in the Nordic countries. While nutrient-poor forests are generally able to maintain their carbon sink status even after drainage, the peat soil at the fertile sites is typically considered as a large carbon dioxide (CO2) source. This means that despite of high timber production capacity, the fertile peatland forests gradually lose their peat carbon store. In addition, many of the nutrient-rich sites emit considerable amount of nitrous oxide (N2O) into the atmosphere. While the current estimates of the greenhouse gas (GHG) balance of forestry-drained peatlands are largely based on soil inventories or on data combining soil GHG fluxes and tree growth litter input measurements and modelling, only few studies have utilized the high-resolution, continuous eddy covariance (EC) data to address the short-term dynamics of the net CO2 fluxes covering both the soil, forest floor vegetation and the trees. Hence, little is known about the factors which control the year-to-year variation in fluxes. Here we present a 5-year dataset of CO2 fluxes measured with the EC method above a nutrient-rich forestry-drained peatland in southern Finland. The site, drained in the beginning of 1970's, is a well growing pine forest with some spruces and birches, the tree volume and carbon fixation rate equaling 8.0 kg C m-2 and 0.273 kg C m-2 yr-1, respectively. The average summer-time water level depth is -50 cm. By combining the gap-filled half-hourly net ecosystem exchange (NEE) data, the tree growth measurements, and the measurements on dissolved organic carbon (DOC) losses and soil methane (CH4) exchange, we will in this presentation estimate the total annual loss of peat carbon of this fertile peatland forest. In addition, using the N2O flux data we will estimate the contribution of different gases to the total GHG balance. Factors controlling the carbon balance and

  18. Botswana water and surface energy balance research program. Part 1: Integrated approach and field campaign results

    Science.gov (United States)

    Vandegriend, A. A.; Owe, M.; Vugts, H. F.; Ramothwa, G. K.

    1992-01-01

    The Botswana water and surface energy balance research program was developed to study and evaluate the integrated use of multispectral satellite remote sensing for monitoring the hydrological status of the Earth's surface. Results of the first part of the program (Botswana 1) which ran from 1 Jan. 1988 - 31 Dec. 1990 are summarized. Botswana 1 consisted of two major, mutually related components: a surface energy balance modeling component, built around an extensive field campaign; and a passive microwave research component which consisted of a retrospective study of large scale moisture conditions and Nimbus scanning multichannel microwave radiometer microwave signatures. The integrated approach of both components in general are described and activities performed during the surface energy modeling component including the extensive field campaign are summarized. The results of the passive microwave component are summarized. The key of the field campaign was a multilevel approach, whereby measurements by various similar sensors were made at several altitudes and resolution. Data collection was performed at two adjacent sites of contrasting surface character. The following measurements were made: micrometeorological measurements, surface temperatures, soil temperatures, soil moisture, vegetation (leaf area index and biomass), satellite data, aircraft data, atmospheric soundings, stomatal resistance, and surface emissivity.

  19. Carbon and greenhouse gas balances in an age-sequence of temperate pine plantations

    Science.gov (United States)

    Peichl, M.; Arain, A. M.; Moore, T. R.; Brodeur, J. J.; Khomik, M.; Ullah, S.; Restrepo-Coupé, N.; McLaren, J.; Pejam, M. R.

    2014-06-01

    This study investigated differences in the magnitude and partitioning of the carbon (C) and greenhouse gas (GHG) balances in an age-sequence of four white pine (Pinus strobus L.) afforestation stands (7, 20, 35 and 70 years old as of 2009) in southern Ontario, Canada. The 4 year (2004-2008) mean annual carbon dioxide (CO2) exchanges, based on biometric and eddy covariance data, were combined with the 2-year means of static chamber measurements of methane (CH4) and nitrous oxide (N2O) fluxes (2006-2007) and dissolved organic carbon (DOC) export below 1 m soil depth (2004-2005). The total ecosystem C pool increased with age from 9 to 160 t C ha-1 across the four stands. Rates of organic matter cycling (i.e. litter-fall and decomposition) were similar among the three older stands. In contrast, considerable differences related to stand age and site quality were observed in the magnitude and partitioning of individual CO2 fluxes showing a peak in production and respiration rates in the middle-age (20 year-old) stand growing on fertile post-agricultural soil. The DOC export accounted for 10% of net ecosystem production (NEP) at the 7 year old stand but < 2% at the three older stands. The GHG balance from the combined exchanges of CO2, CH4 and N2O fluxes was 2.6, 21.6, 13.5 and 4.8 t CO2 eq ha-1 yr-1 for the 7, 20, 35, and 70 year-old stands, respectively. The maximum annual contribution from the combined exchanges of CH4, N2O and DOC to the GHG balance was 8% and 15% in the 7 and 70 year-old stands, respectively, but < 1% in the two highly productive middle-age (20 and 35 year-old) stands. Averaged over the entire age-sequence, the CO2 exchange was the main driver of the GHG balance in these forests. The cumulative CO2 sequestration over the 70 years was estimated at 129 \\unit{t} C and 297 t C ha-1 yr-1 for stands growing on low and high productive sites, respectively. This study highlights the importance of accounting for age and site quality effects on forest C and

  20. Carbon and greenhouse gas balances in an age sequence of temperate pine plantations

    Science.gov (United States)

    Peichl, M.; Arain, A. M.; Moore, T. R.; Brodeur, J. J.; Khomik, M.; Ullah, S.; Restrepo-Coupé, N.; McLaren, J.; Pejam, M. R.

    2014-10-01

    This study investigated differences in the magnitude and partitioning of the carbon (C) and greenhouse gas (GHG) balances in an age sequence of four white pine (Pinus strobus L.) afforestation stands (7, 20, 35 and 70 years old as of 2009) in southern Ontario, Canada. The 4-year (2004-2008) mean annual carbon dioxide (CO2) exchanges, based on biometric and eddy covariance data, were combined with the 2-year means of static chamber measurements of methane (CH4) and nitrous oxide (N2O) fluxes (2006-2007) and dissolved organic carbon (DOC) export below 1 m soil depth (2004-2005). The total ecosystem C pool increased with age from 46 to 197 t C ha-1 across the four stands. Rates of organic matter cycling (i.e. litterfall and decomposition) were similar among the three older stands. In contrast, considerable differences related to stand age and site quality were observed in the magnitude and partitioning of individual CO2 fluxes, showing a peak in production and respiration rates in the middle-age (20-year-old) stand growing on fertile post-agricultural soil. The DOC export accounted for 10% of net ecosystem production (NEP) at the 7-year-old stand but <2% at the three older stands. The GHG balance from the combined exchanges of CO2, CH4 and N2O was 2.6, 21.6, 13.5 and 4.8 t CO2 equivalent ha-1 year-1 for the 7-, 20-, 35- and 70-year-old stands, respectively. The maximum annual contribution from the combined exchanges of CH4 and N2O to the GHG balance was 13 and 8% in the 7- and 70-year-old stands, respectively, but <1% in the two highly productive middle-age (20- and 35-year-old) stands. Averaged over the entire age sequence, the CO2 exchange was the main driver of the GHG balance in these forests. The cumulative CO2 sequestration over the 70 years was estimated at 129 t C and 297 t C ha-1 year-1 for stands growing on low- and high-productivity sites, respectively. This study highlights the importance of accounting for age and site quality effects on forest C and GHG

  1. Calculating carbon mass balance from unsaturated soil columns treated with CaSO₄₋minerals: test of soil carbon sequestration.

    Science.gov (United States)

    Han, Young-Soo; Tokunaga, Tetsu K

    2014-12-01

    Renewed interest in managing C balance in soils is motivated by increasing atmospheric concentrations of CO2 and consequent climate change. Here, experiments were conducted in soil columns to determine C mass balances with and without addition of CaSO4-minerals (anhydrite and gypsum), which were hypothesized to promote soil organic carbon (SOC) retention and soil inorganic carbon (SIC) precipitation as calcite under slightly alkaline conditions. Changes in C contents in three phases (gas, liquid and solid) were measured in unsaturated soil columns tested for one year and comprehensive C mass balances were determined. The tested soil columns had no C inputs, and only C utilization by microbial activity and C transformations were assumed in the C chemistry. The measurements showed that changes in C inventories occurred through two processes, SOC loss and SIC gain. However, the measured SOC losses in the treated columns were lower than their corresponding control columns, indicating that the amendments promoted SOC retention. The SOC losses resulted mostly from microbial respiration and loss of CO2 to the atmosphere rather than from chemical leaching. Microbial oxidation of SOC appears to have been suppressed by increased Ca(2+) and SO4(2)(-) from dissolution of CaSO4 minerals. For the conditions tested, SIC accumulation per m(2) soil area under CaSO4-treatment ranged from 130 to 260 g C m(-1) infiltrated water (20-120 g C m(-1) infiltrated water as net C benefit). These results demonstrate the potential for increasing C sequestration in slightly alkaline soils via CaSO4-treatment.

  2. Interpreting seasonal changes in the carbon balance of southern Amazonia using measurements of XCO2 and chlorophyll fluorescence from GOSAT

    NARCIS (Netherlands)

    Parazoo, Nicholas C.; Bowman, Kevin; Frankenberg, Christian; Lee, Jung-Eun; Fisher, Joshua B.; Worden, John; Jones, Dylan B. A.; Berry, Joseph; Collatz, G. James; Baker, Ian T.; Jung, Martin; Liu, Junjie; Osterman, Gregory; O'Dell, Chris; Sparks, Athena; Butz, Andre; Guerlet, Sandrine; Yoshida, Yukio; Chen, Huilin; Gerbig, Christoph

    2013-01-01

    Amazon forests exert a major influence on the global carbon cycle, but quantifying the impact is complicated by diverse landscapes and sparse data. Here we examine seasonal carbon balance in southern Amazonia using new measurements of column-averaged dry air mole fraction of CO2 (XCO2) and solar ind

  3. Carbon balance of rewetted and drained peat soils used for biomass production: A mesocosm study

    DEFF Research Database (Denmark)

    Karki, Sandhya; Elsgaard, Lars; Kandel, Tanka

    2016-01-01

    Rewetting of drained peatlands has been recommended to reduce CO2 emissions and to restore the carbon sink function of peatlands. Recently, the combination of rewetting and biomass production (paludiculture) has gained interest as a possible land use option in peatlands for obtaining such benefits...... of lower CO2 emissions without losing agricultural land. The present study quantified the carbon balance (CO2, CH4 and harvested biomass C) of rewetted and drained peat soils under intensively managed reed canary grass (RCG) cultivation. Mesocosms were maintained at five different ground water levels (GWL...... closed chamber methods. The average dry biomass yield was significantly lower from rewetted peat soils (12 Mg ha−1) than drained peat soils (15 Mg ha−1). Also, CO2 fluxes of gross primary production (GPP) and ecosystem respiration (ER) from rewetted peat soils were significantly lower than drained peat...

  4. Carbon balance indicates a time limit for cultivation of organic soils in central Switzerland

    Science.gov (United States)

    Paul, Sonja; Ammann, Christof; Alewell, Christine; Leifeld, Jens

    2016-04-01

    Peatlands serve as important carbon sinks. Globally, more than 30% of the soil organic carbon is stored in organic soils, although they cover only 3% of the land surface. The agricultural use of organic soils usually requires drainage thereby transforming these soils from a net carbon sink into a net source. Currently, about 2 to 3 Gt CO2 are emitted world-wide from degrading organic soils (Joosten 2011; Parish et al. 2008) which is ca. 5% of the total anthropogenic emissions. Besides these CO2 emissions, the resulting subsidence of drained peat soils during agricultural use requires that drainage system are periodically renewed and finally to use pumping systems after progressive subsidence. In Switzerland, the Seeland region is characterised by fens which are intensively used for agriculture since 1900. The organic layer is degrading and subsequently getting shallower and the underlying mineral soil, as lake marl or loam, is approaching the surface. The questions arises for how long and under which land use practises and costs these soils can be cultivated in the near future. The study site was under crop rotation until 2009 when it was converted to extensively used grassland with the water regime still being regulated. The soil is characterised by a degraded organic horizon of 40 to 70 cm. Since December 2014 we are measuring the carbon exchange of this grassland using the Eddy-Covariance method. For 2015, the carbon balance indicates that the degraded fen is a strong carbon source, with approximately 500 g C m-2 a-1. The carbon balance is dominated by CO2 emissions and harvest. Methane emissions are negligible. With the gained emission factors different future scenarios are evaluated for the current cultivation practise of organic soils in central Switzerland. Joosten, H., 2011: Neues Geld aus alten Mooren: Über die Erzeugung von Kohlenstoffzertifikaten aus Moorwiedervernässungen. Telma Beiheft 4, 183-202. Parish, F., A. Sirin, D. Charman, H. Joosten, T

  5. The effects of pH on carbon material and energy balances in hydrogen-producing Clostridium tyrobutyricum JM1.

    Science.gov (United States)

    Jo, Ji Hye; Lee, Dae Sung; Park, Jong Moon

    2008-11-01

    The effects of pH on hydrogen fermentation of glucose by newly isolated H(2)-producing bacterium Clostridium tyrobutyricum JM1 were investigated in batch cultivations. The changes of carbon material and energy balances by pH conditions provided useful information for understanding and interpreting the regulatory system of the microorganism, and for optimization of a desired product, in this case, molecular hydrogen. The most probable metabolic pathways of C. tyrobutyricum JM1 were determined through an accurate analysis of stoichiometry and the consistency of the experimental data, checked by high carbon recovery. The carbon material and energy balances were adequately applied to estimate the carbon-flow distribution. They suggested that pH 6.3 was appropriate to maximize hydrogen production with a high concentration of butyrate and balanced activities of NADH.

  6. A simple, mass balance model of carbon flow in a controlled ecological life support system

    Science.gov (United States)

    Garland, Jay L.

    1989-01-01

    Internal cycling of chemical elements is a fundamental aspect of a Controlled Ecological Life Support System (CELSS). Mathematical models are useful tools for evaluating fluxes and reservoirs of elements associated with potential CELSS configurations. A simple mass balance model of carbon flow in CELSS was developed based on data from the CELSS Breadboard project at Kennedy Space Center. All carbon reservoirs and fluxes were calculated based on steady state conditions and modelled using linear, donor-controlled transfer coefficients. The linear expression of photosynthetic flux was replaced with Michaelis-Menten kinetics based on dynamical analysis of the model which found that the latter produced more adequate model output. Sensitivity analysis of the model indicated that accurate determination of the maximum rate of gross primary production is critical to the development of an accurate model of carbon flow. Atmospheric carbon dioxide was particularly sensitive to changes in photosynthetic rate. The small reservoir of CO2 relative to large CO2 fluxes increases the potential for volatility in CO2 concentration. Feedback control mechanisms regulating CO2 concentration will probably be necessary in a CELSS to reduce this system instability.

  7. Stress differentially impacts reserve pools and root exudation: implications for ecosystem functioning and carbon balance

    Science.gov (United States)

    Landhäusser, Simon; Karst, Justine; Wiley, Erin; Gaster, Jacob

    2016-04-01

    Environmental stress can influence carbon assimilation and the accumulation and distribution of carbon between growth, reserves, and exudation; however, it is unclear how these processes vary by different stress types. Partitioning of carbon to growth and reserves in plants might also vary between different organs. Roots reserves are of particular interest as they link the plant with the soil carbon cycle through exudation. Simple models of diffusion across concentration gradients predict the more C reserves in roots, the more C should be exuded from roots. However, the mechanisms underlying the accumulation and loss of C from roots may differ depending on the stress experienced by the plants. In a controlled study we tested whether different types of stresses (shade, cold soil, and drought) have differential effects on the distribution, abundance, and form (sugar vs. starch) of carbohydrates in seedlings, and whether these changes alone could explain differences in root exudation between stress types. Non-structural carbohydrate (NSC) concentration and pool sizes varied by stress type and between organs. Mass-specific C exudation increased with fine root sugar concentration; however, stress type affected exudation independently of reserve concentration. Seedlings exposed to cold soils exuded the most C on a per root mass basis followed by shade and drought. Through 13C labeling, we also found that depending on the stress type, aspen seedlings may be less able to control the loss of C to the soil compared with unstressed seedlings, resulting in more C leaked to the rhizosphere. The loss of C beyond that predicted by simple concentration gradients might have important implications for ecosystem functioning and carbon balance. If stressed plants lose proportionally more carbon to the soil, existing interactions between plants and soils may decouple under stress, and may include unexpected C fluxes between trees, soils and the atmosphere with a changing climate.

  8. Carbon leaching from tropical peat soils and consequences for carbon balances

    Science.gov (United States)

    Rixen, Tim; Baum, Antje; Wit, Francisca; Samiaji, Joko

    2016-07-01

    Drainage and deforestation turned Southeast (SE) Asian peat soils into a globally important CO2 source, because both processes accelerate peat decomposition. Carbon losses through soil leaching have so far not been quantified and the underlying processes have hardly been studied. In this study, we use results derived from nine expeditions to six Sumatran rivers and a mixing model to determine leaching processes in tropical peat soils, which are heavily disturbed by drainage and deforestation. Here we show that a reduced evapotranspiration and the resulting increased freshwater discharge in addition to the supply of labile leaf litter produced by re-growing secondary forests increase leaching of carbon by ~200%. Enhanced freshwater fluxes and leaching of labile leaf litter from secondary vegetation appear to contribute 38% and 62% to the total increase, respectively. Decomposition of leached labile DOC can lead to hypoxic conditions in rivers draining disturbed peatlands. Leaching of the more refractory DOC from peat is an irrecoverable loss of soil that threatens the stability of peat-fringed coasts in SE Asia.

  9. Carbon and greenhouse gas balances in an age-sequence of temperate pine plantations

    Directory of Open Access Journals (Sweden)

    M. Peichl

    2014-06-01

    Full Text Available This study investigated differences in the magnitude and partitioning of the carbon (C and greenhouse gas (GHG balances in an age-sequence of four white pine (Pinus strobus L. afforestation stands (7, 20, 35 and 70 years old as of 2009 in southern Ontario, Canada. The 4 year (2004–2008 mean annual carbon dioxide (CO2 exchanges, based on biometric and eddy covariance data, were combined with the 2-year means of static chamber measurements of methane (CH4 and nitrous oxide (N2O fluxes (2006–2007 and dissolved organic carbon (DOC export below 1 m soil depth (2004–2005. The total ecosystem C pool increased with age from 9 to 160 t C ha−1 across the four stands. Rates of organic matter cycling (i.e. litter-fall and decomposition were similar among the three older stands. In contrast, considerable differences related to stand age and site quality were observed in the magnitude and partitioning of individual CO2 fluxes showing a peak in production and respiration rates in the middle-age (20 year-old stand growing on fertile post-agricultural soil. The DOC export accounted for 10% of net ecosystem production (NEP at the 7 year old stand but 2, CH4 and N2O fluxes was 2.6, 21.6, 13.5 and 4.8 t CO2 eq ha−1 yr−1 for the 7, 20, 35, and 70 year-old stands, respectively. The maximum annual contribution from the combined exchanges of CH4, N2O and DOC to the GHG balance was 8% and 15% in the 7 and 70 year-old stands, respectively, but 2 exchange was the main driver of the GHG balance in these forests. The cumulative CO2 sequestration over the 70 years was estimated at 129 \\unit{t} C and 297 t C ha−1 yr−1 for stands growing on low and high productive sites, respectively. This study highlights the importance of accounting for age and site quality effects on forest C and GHG balances. It further demonstrates a large potential for C sequestration and climate benefits (i.e. cooling effect gained through afforestation of marginal agricultural and

  10. Carbon balance and greenhouse gas emissions of subarctic lowland palsa mires related to permafrost degradation.

    Science.gov (United States)

    Stiegler, Christian; Lindroth, Anders; Christensen, Torben R.; Johansson, Margareta

    2014-05-01

    The Torneträsk area in northern subarctic Sweden is particularly vulnerable to any further climate change since it is located on the 0-degree isotherm. Within the next decades a projected ongoing climate warming and increase in snow cover will most likely lead to the disappearance of lowland permafrost in this region, affecting greenhouse gas emissions, surface energy fluxes and vegetation cover. A previous study from the Torneträsk area has resulted in extensive data on the effects of permafrost degradation on surface energy balance. In this study we focus on the effects of different stages of permafrost degradation on carbon balance and emission of greenhouse gases. The study area covers several mires with similar local topographic conditions along an east-west oriented transect. Due to a strong climatic gradient, with maritime climate in the west and a more continental climate in the east, active layer thickness and permafrost temperatures generally increase from east to west while permafrost thickness decreases. In recent years permafrost has completely disappeared at the westernmost study site while at the other investigated locations the peat plateaus show varying stages of degradation. For our measurements we use both mobile and stationary energy balance and eddy covariance towers. Data has been collected during the growing season in 2013 by measuring flux densities of carbon dioxide and water vapour and all components of the surface energy budget, i.e. net radiation, turbulent fluxes of sensible and latent heat as well as ground heat fluxes. In addition, we measure active layer thickness and both soil moisture and soil temperature at various depths. In this study we aim to (A) investigate and better understand the effects of permafrost degradation on the CO2 dynamics in subarctic palsa mires, (B) assess variation in terrestrial CO2 and water vapour flux with changes in vegetation cover and soil moisture, (C) determine possible meteorological and

  11. Dynamic modelling and humus balances as tools for estimating and upscaling soil carbon stock changes in temperate cropland

    Science.gov (United States)

    Oberholzer, Hans-Rudolf; Holenstein, Hildegard; Mayer, Jochen; Leifeld, Jens

    2010-05-01

    Humus balances are simple mathematical tools used by farmers for assessing the overall performance of their management in terms of soil organic matter changes. They are based on humus reproduction factors which themselves mainly depend on crop rotation, residue management, and amount and type of organic fertilization. Dynamic models, on the other hand, are typically complex and need more detailed input data and are designed to calculate the time course of soil carbon content. In both cases, thorough validation is needed to utilize their potential for estimating carbon stock changes. We compared the results of three humus balance methods SALCA-SQ (Neyroud 1997), VDLUFA method (VDLUFA 2004), Humod (Brock et al. 2008) and the RothC model with measured soil carbon stocks in a long-term experiment in Switzerland for the period 1977-2005 (Fliessbach et al 2007). The field trial comprises various minerally and organically fertilized treatments, the latter differing in the amount and composition of organics applied. All methods were able to distinguish systematic management effects on soil organic carbon (SOC). However, only those SOC trajectories calculated with the dynamic model RothC matched measured stocks quantitatively. For both, humus balances and dynamic modelling the result strongly depended on parameterization of organic fertilizers, i.e. its stability and organic matter content. Therefore, incomplete information on the amount and composition of organic fertilizer and lack of knowledge about its potential for humus reproduction is regarded an uncertainty in both dynamic modelling and humus balance calculation, and seems to be a major drawback for the reliable application of these approaches at the regional scale. Our results stress the need for more detailed and harmonized data bases of organic fertilizer composition and application rates. References Brock C., Hoyer U., Leithold G., Hülsbergen K.-J., 2008. Entwicklung einer praxisanwendbaren Methode der

  12. Dissolved Carbon Flux and Mass Balance From a Wetland-Dominated Karstic Headwater Catchment

    Science.gov (United States)

    Duval, T. P.; Waddington, J. M.; Branfireun, B. A.

    2009-05-01

    The stream-borne dissolved carbon efflux of peatland-draining catchments is dominated by organic carbon, whereas inorganic carbon dominates the flux from calcareous bedrock catchments. The export of dissolved carbon from calcareous bedrock catchments with significant wetland coverage has not previously been determined. This study documents the spatiotemporal variability of dissolved carbon (inorganic + organic) along a headwater stream in southern Ontario, Canada, as it drains three distinct wetland types: a calcareous fen, a riparian cedar swamp, and a cattail marsh. Upon emergence from the groundwater seeps, the spring water contained 28 times more CO2 than in equilibrium with the atmosphere. This supersaturation decreased to just 5 times equilbrium as the stream leaves the catchment through the marsh, representing a decrease in CO2 concentration of 11 mg L-1, lost to the atmosphere as exsolution. The groundwater seeps contained an average of 1.25±0.75 mg L-1 of dissolved organic carbon (DOC) from May to November 2007, one of the driest years on record in the region. At the catchment outlet through the marsh, DOC concentrations were slightly higher and more variable during the same period at 2.27±1.29 mg L-1, as a fall flushing event resulted in concentrations > 7 mg L-1. This DOC concentration is small compared to the 58.72±3.9 mg L-1 of dissolved inorganic carbon (DIC, as bicarbonate ion) contained within the water leaving the catchment. At 0.21 and 0.17 g m-2 d-1 from May-July and August-November 2007, respectively, the DIC dominated the carbon flux out of the watershed, compared with 0.007 and 0.008 g m- 2 d-1 DOC and 0.015 and 0.009 g m-2 d-1 CO2 exsolution during the same period. Results of the 2007 season will be contrasted to the 2008 season, one of the wettest on record. The watershed is underlain by Silurian dolomite that exhibits karst fractures, resulting in a complex subsurface hydrogeology that influences carbon transport and mass balances

  13. Stagnating crop yields: An overlooked risk for the carbon balance of agricultural soils?

    Science.gov (United States)

    Wiesmeier, Martin; Hübner, Rico; Kögel-Knabner, Ingrid

    2015-12-01

    The carbon (C) balance of agricultural soils may be largely affected by climate change. Increasing temperatures are discussed to cause a loss of soil organic carbon (SOC) due to enhanced decomposition of soil organic matter, which has a high intrinsic temperature sensitivity. On the other hand, several modeling studies assumed that potential SOC losses would be compensated or even outperformed by an increased C input by crop residues into agricultural soils. This assumption was based on a predicted general increase of net primary productivity (NPP) as a result of the CO2 fertilization effect and prolonged growing seasons. However, it is questionable if the crop C input into agricultural soils can be derived from NPP predictions of vegetation models. The C input in European croplands is largely controlled by the agricultural management and was strongly related to the development of crop yields in the last decades. Thus, a glance at past yield development will probably be more instructive for future estimations of the C input than previous modeling approaches based on NPP predictions. An analysis of European yield statistics indicated that yields of wheat, barley and maize are stagnating in Central and Northern Europe since the 1990s. The stagnation of crop yields can probably be related to a fundamental change of the agricultural management and to climate change effects. It is assumed that the soil C input is concurrently stagnating which would necessarily lead to a decrease of agricultural SOC stocks in the long-term given a constant temperature increase. Remarkably, for almost all European countries that are faced with yield stagnation indications for agricultural SOC decreases were already found. Potentially adverse effects of yield stagnation on the C balance of croplands call for an interdisciplinary investigation of its causes and a comprehensive monitoring of SOC stocks in agricultural soils of Europe.

  14. Diurnal and seasonal carbon balance of four tropical tree species differing in successional status

    Directory of Open Access Journals (Sweden)

    GM. Souza

    Full Text Available This study addressed some questions about how a suitable leaf carbon balance can be attained for different functional groups of tropical tree species under contrasting forest light environments. The study was carried out in a fragment of semi-deciduous seasonal forest in Narandiba county, São Paulo Estate, Brazil. 10-month-old seedlings of four tropical tree species, Bauhinia forficata Link (Caesalpinioideae and Guazuma ulmifolia Lam. (Sterculiaceae as light-demanding pioneer species, and Hymenaea courbaril L. (Caesalpinioideae and Esenbeckia leiocarpa Engl. (Rutaceae as late successional species, were grown under gap and understorey conditions. Diurnal courses of net photosynthesis (Pn and transpiration were recorded with an open system portable infrared gas analyzer in two different seasons. Dark respiration and photorespiration were also evaluated in the same leaves used for Pn measurements after dark adaptation. Our results showed that diurnal-integrated dark respiration (Rdi of late successional species were similar to pioneer species. On the other hand, photorespiration rates were often higher in pioneer than in late successional species in the gap. However, the relative contribution of these parameters to leaf carbon balance was similar in all species in both environmental conditions. Considering diurnal-integrated values, gross photosynthesis (Pgi was dramatically higher in gap than in understorey, regardless of species. In both evaluated months, there were no differences among species of different functional groups under shade conditions. The same was observed in May (dry season under gap conditions. In such light environment, pioneers were distinguished from late successional species in November (wet season, showing that ecophysiological performance can have a straightforward relation to seasonality.

  15. Net carbon balance of three full crop rotations at an agricultural site near Gebesee, Germany

    Science.gov (United States)

    Hurkuck, M.; Brümmer, C.; Kolle, O.; Kutsch, W. L.; Moffat, A. M.; Mukwashi, K.; Truckenbrodt, S. C.; Herbst, M.

    2015-12-01

    Continuous eddy-covariance (EC) measurements of biosphere-atmosphere CO2 and H2O exchange have been conducted since 2001 at an agricultural site near Gebesee, Germany, thus providing one of the longest EC time series of European croplands. During the experimental period, winter wheat and winter barley were alternately planted with potatoes, sugar beet, rape, and peppermint covering three full crop rotations (2001-2004, 2005-2009, and 2010-2014). In this study, data of 14 years of net ecosystem CO2 exchange (NEE) and evapotranspiration (E) were re-calculated. Based on these data, we present the net carbon (C) balance (net biome production, NBP) accounting for any additional C input by fertilization and C output by harvest. Further emphasis was placed on the sensitivity of water use efficiency (WUE) and E to climate and crop type. The main aim was to investigate the interannual variability in both NBP and WUE, thus disentangling the impacts of climatic conditions and land management on the net C balance as well as on WUE and E.

  16. The carbon balance of South America: a review of the status, decadal trends and main determinants

    Directory of Open Access Journals (Sweden)

    M. Gloor

    2012-12-01

    Full Text Available We summarise the contemporary carbon budget of South America and relate it to its dominant controls: population and economic growth, changes in land use practices and a changing atmospheric environment and climate. Component flux estimate methods we consider sufficiently reliable for this purpose encompass fossil fuel emission inventories, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on remote sensing and inventories, and agricultural export data. Alternative methods for the estimation of the continental-scale net land to atmosphere CO2 flux, such as atmospheric transport inverse modelling and terrestrial biosphere model predictions, are, we find, hampered by the data paucity, and improved parameterisation and validation exercises are required before reliable estimates can be obtained. From our analysis of available data, we suggest that South America was a net source to the atmosphere during the 1980s (~ 0.3–0.4 Pg C a−1 and close to neutral (~ 0.1 Pg C a−1 in the 1990s. During the latter period, carbon uptake in old-growth forests nearly compensated for the carbon release associated with fossil fuel burning and deforestation.

    Annual mean precipitation over tropical South America as inferred from Amazon River discharge shows a long-term upward trend. Although, over the last decade dry seasons have tended to be drier, with the years 2005 and 2010 in particular experiencing strong droughts. On the other hand, precipitation during the wet seasons also shows an increasing trend. Air temperatures have also increased slightly. Also with increases in atmospheric CO2 concentrations, it is currently unclear what effect these climate changes are having on the forest carbon balance of the region. Current indications are that the forests of the Amazon Basin have acted as a substantial long-term carbon sink, but with the most recent

  17. The carbon balance of South America: status, decadal trends and main determinants

    Directory of Open Access Journals (Sweden)

    M. Gloor

    2012-01-01

    Full Text Available We attempt to summarize the carbon budget of South America and relate it to its dominant controls: population and economic growth, changes in land use practices and a changing atmospheric environment and climate. Flux estimation methods which we consider sufficiently reliable are fossil fuel emission inventories, biometric analysis of old-growth rainforests, estimation of carbon release associated with deforestation based on remote sensing and inventories, and finally inventories of agricultural exports. Other routes to estimating land-atmosphere CO2 fluxes include atmospheric transport inverse modelling and vegetation model predictions but are hampered by the data paucity and the need for improved parameterisation. The available data we analyze suggest that South America was a net source to the atmosphere during the 1980s (∼0.3–0.4 Pg C yr−1 and close to neutral (∼0.1 Pg C yr−1 in the 1990s with carbon uptake in old-growth forests nearly compensating carbon losses due to fossil fuel burning and deforestation. Annual mean precipitation over tropical South America measured by Amazon River discharge has a long-term upward trend, although over the last decade, dry seasons have tended to be drier and longer (and thus wet seasons wetter, with the years 2005 and 2010 experiencing strong droughts. It is currently unclear what the effect of these climate changes on the old-growth forest carbon sink will be but first measurements suggest it may be weakened. Based on scaling of forest census data the net carbon balance of South America seems to have been an increased source roughly over the 2005–2010 period (a total of ∼1 Pg C of dead tree biomass released over several years due to forest drought response. Finally, economic development of the tropical forest regions of the continent is advancing steadily with exports of agricultural products being an important driver and witnessing a strong upturn over the

  18. Modelling Temporal Variability in the Carbon Balance of a Spruce/Moss Boreal Forest

    Science.gov (United States)

    Frolking, S.; Goulden, M. L.; Wofsy, S. C.; Fan, S.-M.; Sutton, D. J.; Munger, J. W.; Bazzaz, A. M.; Daube, B. C.; Crill, P. M.; Aber, J. D.; Band, L. E.; Wang, X.; Savages, K.; Moore, T.; Harriss, R. C.

    1996-01-01

    A model of the daily carbon balance of a black spruce/feathermoss boreal forest ecosystem was developed and results compared to preliminary data from the 1994 BOREAS field campaign in northern Manitoba, Canada. The model, driven by daily weather conditions, simulated daily soil climate status (temperature and moisture profiles), spruce photosynthesis and respiration, moss photosynthesis and respiration, and litter decomposition. Model agreement with preliminary field data was good for net ecosystem exchange (NEE), capturing both the asymmetrical seasonality and short-term variability. During the growing season simulated daily NEE ranged from -4 g C m(exp -2) d(exp -1) (carbon uptake by ecosystem) to + 2 g C m(exp -2) d(exp -1) (carbon flux to atmosphere), with fluctuations from day to day. In the early winter simulated NEE values were + 0.5 g C m(exp -2) d(exp -1), dropping to + 0.2 g C m(exp -2) d(exp -1) in mid-winter. Simulated soil respiration during the growing season (+ 1 to + 5 g C m(exp -2) d(exp -1)) was dominated by metabolic respiration of the live moss, with litter decomposition usually contributing less than 30% and live spruce root respiration less than 10% of the total. Both spruce and moss net primary productivity (NPP) rates were higher in early summer than late summer. Simulated annual NEE for 1994 was -51 g C m(exp -2) y(exp -1), with 83% going into tree growth and 17% into the soil carbon accumulation. Moss NPP (58 g C m(exp -2) d(exp -1)) was considered to be litter (i.e. soil carbon input; no net increase in live moss biomass). Ecosystem respiration during the snow-covered season (84 g Cm(exp -2)) was 58% of the growing season net carbon uptake. A simulation of the same site for 1968-1989 showed about 10-20% year-to-year variability in heterotrophic respiration (mean of + 113 g C m-2 y@1). Moss NPP ranged from 19 to 114 g C m(exp -2) y(exp -1); spruce NPP from 81 to 150 g C nt-2 y,@l; spruce growth (NPP minus litterfall) from 34 to 103 g C m

  19. Effect of Forest Management of Picea abies and Fagus sylvatica with Different Types of Felling on Carbon and Economic Balances in the Czech Republic

    Science.gov (United States)

    Plch, Radek; Pulkrab, Karel; Bukáček, Jan; Sloup, Roman; Cudlín, Pavel

    2016-10-01

    The selection of the most sustainable forest management under given site conditions needs suitable criteria and indicators. For this purpose, carbon and economic balance assessment, completed with environmental impact computation using the Life Cycle Assessment (LCA) were used. The aim of this study was to compare forestry operations and wood production of selected forest stands with different i) tree species composition (Norway spruce - Picea abies and European beech - Fagus sylvatica) and ii) type of felling (chainsaw and harvester). Carbon and economic balance methods consist in the comparison of quantified inputs (fossil fuels, electricity, used machinery, fertilizers, etc., converted into emission units of carbon in Mg of C- CO2-eq. or EUR) with quantified outputs (biomass production in Mg of carbon or EUR). In this contribution, similar forest stands (“forest site complexes”) in the 4th forest vegetation zone (in the Czech Republic approximately 400-700 m above sea-level) were selected. Forestry operations were divided into 5 main stages: i) seedling production, ii) stand establishment and pruning, iii) thinning and final cutting, iv) skidding, and v) secondary timber transport and modelled for one rotation period of timber production (ca. 100 years). The differences between Norway spruce and European beech forest stands in the carbon efficiency were relatively small while higher differences were achieved in the economic efficiency (forest stands with Norway spruce had a higher economic efficiency). Concerning the comparison of different types of felling in Norway spruce forest stands, the harvester use proved to induce significantly higher environmental impacts (emission of carbon) and lower economic costs. The comparison of forestry operation stages showed that the main part of carbon emissions, originating from fuel production and combustion, is connected with a thinning and final cutting, skidding and secondary timber transport in relations to

  20. Interpreting seasonal changes in the carbon balance of southern Amazonia using measurements of XCO2 and chlorophyll fluorescence from GOSAT

    OpenAIRE

    Parazoo, Nicholas C.; Bowman, Kevin; Frankenberg, Christian; Lee, Jung-Eun; Fisher, Joshua B.; Worden, John; Jones, Dylan B. A.; Berry, Joseph; Collatz, G James; Baker, Ian T.; Jung, Martin; Liu, Junjie; Osterman, Gregory; O'Dell, Chris; Sparks, Athena

    2013-01-01

    Amazon forests exert a major influence on the global carbon cycle, but quantifying the impact is complicated by diverse landscapes and sparse data. Here we examine seasonal carbon balance in southern Amazonia using new measurements of column-averaged dry air mole fraction of CO_2 (XCO_2) and solar induced chlorophyll fluorescence (SIF) from the Greenhouse Gases Observing Satellite (GOSAT) from July 2009 to December 2010. SIF, which reflects gross primary production (GPP), is used to disentang...

  1. Brazilian environmental legislation and scenarios for carbon balance in Areas of Permanent Preservation (APP) in dairy livestock regions

    Science.gov (United States)

    Hott, M. C.; Fonseca, L. D.; Andrade, R. G.

    2011-12-01

    The present study aimed at mapping some categories of Areas of Permanent Preservation (APP) for natural regeneration of semideciduous forests in the regions of Zona da Mata and Campo das Vertentes, Minas Gerais State (Figure 1), and from this to establish what impact the deployment of APP over area of pastures and subsequently milk production and carbon sequestration, considering areas of pasture as one of major factors for the dairy farming in the regions concerned. From the altimetric information from MDE, it was possible to extract morphological and morphometrical data to estimate the areas of APP. We used imagery of MODIS/Terra for extraction of the pastures areas from the vegetation index data NDVI to intersect with the estimated area of APP. In a linear or deterministic scenario of deployment of APPs over in the pasture areas considering that wich are proportionately responsible for sizing the herd, and thus for the milk production in extensive livestock, despite the existence of numerous other factors, there would be an impact 12% in the production of Campo das Vertentes region and 21.5% for the Zona da Mata. In this scenario, according to the carbon balance of forests and livestock, there would be a positive balance with the deployment of areas of permanent preservation and, subsequent promotion of natural regeneration. Considering the current grazing area of the Zona da Mata and Campo das Vertentes, 1.6 million hectares, with the carbon balance estimated at 1 ton/hectare/year, 300,000 hectares would have a balance of 5 ton/hectare/year in whole cycle of 40 years, totaling 200 tons carbon by hectare, or additional 48 million tons fixed, considering 4 tons more than pastures in the case of semideciduous forest. At the end of the cycle or forest climax, there would still be positive carbon balance, estimated as a balance of 2 ton/hectare/year. However, despite the higher carbon balance for the semideciduous forest, compared to livestock, it is important to

  2. Current and future impacts of ultraviolet radiation on the terrestrial carbon balance

    Institute of Scientific and Technical Information of China (English)

    W. Kolby SMITH; Wei GAO; Heidi STELTZER

    2009-01-01

    One of the most documented effects of human activity on our environment is the reduction of stratospheric ozone resulting in an increase of biologically harmful ultraviolet (UV) radiation. In a less predictable manner, UV radiation incident at the surface of the earth is expected to be further modified in the future as a result of altered cloud condition, atmospheric aerosol concentration, and snow cover. Although UV radiation comprises only a small fraction of the total solar radiation that is incident at the earth's surface, it has the greatest energy per unit wavelength and, thus, the greatest potential to damage the biosphere. Recent investigations have highlighted numerous ways that UV radiation could potentially affect a variety of ecological processes, including nutrient cycling and the terrestrial carbon cycle. The objectives of the following literature review are to summarize and synthesize the available information relevant to the effects of UV radiation and other climate change factors on the terrestrial carbon balance in an effort to highlight current gaps in knowledge and future research directions for UV radiation research.

  3. The impacts of disturbance on the spatial and temporal variations of carbon balance in forest ecosystems on Hokkaido, Japan

    Science.gov (United States)

    Hirata, R.; Ito, A.; Saigusa, N.

    2013-12-01

    Carbon balance in a forest ecosystem can be quite variable if the forest ecosystem structure and function change abruptly as a result of disturbance and subsequent recovery processes. A map of forest age is useful for upscaling carbon balance from the site level to a regional scale because it provides information about when disturbance occurred and how it spread over a wide area. In this study, we used maps of forest age to help evaluate spatial and temporal variations in the carbon balance of forest ecosystems with a process-based ecosystem model. Forests less than 60 years old account for more than 70% of Japanese forests because forest stands have been quickly replaced after disturbance caused by thinning, harvesting, plantations, fires, typhoons, and insect damage. However, few studies have attempted to quantify how much disturbance affects the spatial and temporal variations of carbon balance. In this study, we focused on how disturbance and subsequent re-growth affected the spatial and temporal variations of the carbon balance of forests. We adapted the Vegetation Integrative SImulator for Trace Gases (VISIT) model in order to simulate carbon balance on Hokkaido, which is the northernmost island of Japan. The model was validated with tower flux data obtained from forests with ages between 0 and 43 years. Simulations of the carbon balance were conducted for the period 1948-2010 after a 1000-year spin-up at a spatial resolution of 1 km × 1 km. We investigated two case studies of simulated carbon balance: one that took into account the spatial distribution of forest ages derived from forest inventory data, and another that ignored the impact of disturbance (i.e., no disturbance and a homogeneous distribution of ages). We first focused on the difference from 2000-2010 in the spatial distribution of net ecosystem production (NEP) between the disturbance and non-disturbance cases. In the non-disturbance case, the temporal and spatial changes in NEP were gradual

  4. Forest Management Shifts in the Western US and Potential Impacts on the Carbon Balance

    Science.gov (United States)

    Law, B. E.; Jones, M. O.; Yang, Z.; Berner, L. T.

    2015-12-01

    Forest harvest regimes are changing as land managers cope with fires, drought, and insect damage. Thinning on public lands, typically focused on removal of small trees that could act as fuel ladders, is increasing to reduce risk of crown fires and reduce competition for water in crowded stands. On private lands, drought and wildfires could lead to further shortening of harvest cycles (e.g. from 80 to 45 years) or thinning. To examine the effects of potential changes in management regimes vs climate on carbon processes in forests of Oregon, California and Washington, we used data from ancillary plots, inventories, and satellites to parameterize and test the CLM4.5 model. We first examined contemporary biomass loss over the western US to determine the baseline conditions prior to implementing harvest scenarios. Annual biomass mortality from fires and insects increased significantly (1996-2011), and mortality from insects was about twice that of fires. California, Oregon and Idaho were most impacted by fire-related biomass mortality, whereas Colorado, Montana and Washington were most impacted by insects. Harvest scenarios implemented in CLM4.5 include two thinning scenarios to reduce crown fire risk and drought stress, and a salvage scenario to remove trees remaining after recent beetle or fire related mortality; taking into account our previous work showing 70 - 85 % of salvaged biomass is removed and the remainder is left on-site. We simulated the effect of treatments on current and future net ecosystem carbon balance. Challenges of regional modeling of management effects on carbon and other important considerations are addressed.

  5. Results of monitoring large carbon fiber post-tensioning systems in a balanced Cantilever Brdige (Dintelharbour Bridge, The Netherlands)

    NARCIS (Netherlands)

    Vervuurt, A.H.J.M.; Kaptijn, N.; Hageman, J.G.; Kuilboer, C.P.M.

    2012-01-01

    Steel post-tensioning systems and stay cables are susceptible to corrosion. Carbon fiber systems are not. However, there was no experience on the long term behavior of such post-tensioned elements. Four external tendons (75 m long), stressed to a load of 2650 kN, were applied in a large balanced can

  6. Carbon Management In the Post-Cap-and-Trade Carbon Economy-Part II

    Science.gov (United States)

    DeGroff, F. A.

    2014-12-01

    This is the second installment in our search for a comprehensive economic model to mitigate climate change due to anthropogenic activity. Last year we presented how the unique features of our economic model measure changes in carbon flux due to anthropogenic activity, referred to as carbon quality or CQ, and how the model is used to value such changes in the climate system. This year, our paper focuses on how carbon quality can be implemented to capture the effect of economic activity and international trade on the climate system, thus allowing us to calculate a Return on Climate System (RoCS) for all economic assets and activity. The result is that the RoCS for each public and private economic activity and entity can be calculated by summing up the RoCS for each individual economic asset and activity in which an entity is engaged. Such a macro-level scale is used to rank public and private entities including corporations, governments, and even entire nations, as well as human adaptation and carbon storage activities, providing status and trending insights to evaluate policies on both a micro- and macro-economic level. With international trade, RoCS measures the embodied effects on climate change that will be needed to assess border fees to insure carbon parity on all imports and exports. At the core of our vision is a comprehensive, 'open-source' construct of which our carbon quality metric is the first element. One goal is to recognize each country's endemic resources and infrastructure that affect their ability to manage carbon, while preventing spatial and temporal shifting of carbon emissions that reduce or reverse efforts to mitigate climate change. The standards for calculating the RoCS can be promulgated as part of the Generally Accepted Accounted Principles (GAAP) and the International Financial Reporting Standards (IFRS) to ensure standard and consistent reporting. The value of such insights on the climate system at all levels will be crucial to managing

  7. Applying hot wire anemometry to directly measure the water balance in a proton exchange membrane fuel cell - Part 1

    DEFF Research Database (Denmark)

    Berning, Torsten; Al Shakhshir, Saher

    2015-01-01

    In order to accurately determine the water balance of a proton exchange membrane fuel cell it has recently been suggested to employ constant temperature anemometry (CTA), a frequently used method to measure the velocity of a fluid stream. CTA relies on convective heat transfer around a heated wire...... at around 200 °C. The heat loss to the fluid stream is balanced by electrical power dissipation, and the required voltage E is the output signal which is highly sensitive to the heat transfer coefficient of the wire and therefore provides accurate readings. This work explains the theory and summarizes...... the equations required to calculate the heat transfer coefficient and the resulting voltage signal as function of the fuel cell water balance. The most critical and least understood part is the determination of the Nusselt number to calculate the heat transfer between the wire and the gas stream. Different...

  8. Costs of defense and a test of the carbon-nutrient balance and growth-differentiation balance hypotheses for two co-occurring classes of plant defense.

    Directory of Open Access Journals (Sweden)

    Tara Joy Massad

    Full Text Available One of the goals of chemical ecology is to assess costs of plant defenses. Intraspecific trade-offs between growth and defense are traditionally viewed in the context of the carbon-nutrient balance hypothesis (CNBH and the growth-differentiation balance hypothesis (GDBH. Broadly, these hypotheses suggest that growth is limited by deficiencies in carbon or nitrogen while rates of photosynthesis remain unchanged, and the subsequent reduced growth results in the more abundant resource being invested in increased defense (mass-balance based allocation. The GDBH further predicts trade-offs in growth and defense should only be observed when resources are abundant. Most support for these hypotheses comes from work with phenolics. We examined trade-offs related to production of two classes of defenses, saponins (triterpenoids and flavans (phenolics, in Pentaclethra macroloba (Fabaceae, an abundant tree in Costa Rican wet forests. We quantified physiological costs of plant defenses by measuring photosynthetic parameters (which are often assumed to be stable in addition to biomass. Pentaclethra macroloba were grown in full sunlight or shade under three levels of nitrogen alone or with conspecific neighbors that could potentially alter nutrient availability via competition or facilitation. Biomass and photosynthesis were not affected by nitrogen or competition for seedlings in full sunlight, but they responded positively to nitrogen in shade-grown plants. The trade-off predicted by the GDBH between growth and metabolite production was only present between flavans and biomass in sun-grown plants (abundant resource conditions. Support was also only partial for the CNBH as flavans declined with nitrogen but saponins increased. This suggests saponin production should be considered in terms of detailed biosynthetic pathway models while phenolic production fits mass-balance based allocation models (such as the CNBH. Contrary to expectations based on the two

  9. Mass, energy and material balances of SRF production process. Part 3: solid recovered fuel produced from municipal solid waste.

    Science.gov (United States)

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

    2015-02-01

    This is the third and final part of the three-part article written to describe the mass, energy and material balances of the solid recovered fuel production process produced from various types of waste streams through mechanical treatment. This article focused the production of solid recovered fuel from municipal solid waste. The stream of municipal solid waste used here as an input waste material to produce solid recovered fuel is energy waste collected from households of municipality. This article presents the mass, energy and material balances of the solid recovered fuel production process. These balances are based on the proximate as well as the ultimate analysis and the composition determination of various streams of material produced in a solid recovered fuel production plant. All the process streams are sampled and treated according to CEN standard methods for solid recovered fuel. The results of the mass balance of the solid recovered fuel production process showed that 72% of the input waste material was recovered in the form of solid recovered fuel; 2.6% as ferrous metal, 0.4% as non-ferrous metal, 11% was sorted as rejects material, 12% as fine faction and 2% as heavy fraction. The energy balance of the solid recovered fuel production process showed that 86% of the total input energy content of input waste material was recovered in the form of solid recovered fuel. The remaining percentage (14%) of the input energy was split into the streams of reject material, fine fraction and heavy fraction. The material balances of this process showed that mass fraction of paper and cardboard, plastic (soft) and wood recovered in the solid recovered fuel stream was 88%, 85% and 90%, respectively, of their input mass. A high mass fraction of rubber material, plastic (PVC-plastic) and inert (stone/rock and glass particles) was found in the reject material stream.

  10. Effects of a windthrow disturbance on the carbon balance of a broadleaf deciduous forest in Hokkaido, Japan

    Directory of Open Access Journals (Sweden)

    K. Yamanoi

    2015-12-01

    Full Text Available Forests play an important role in the terrestrial carbon balance, with most being in a carbon sequestration stage. The net carbon releases that occur result from forest disturbance, and windthrow is a typical disturbance event affecting the forest carbon balance in eastern Asia. The CO2 flux has been measured using the eddy covariance method in a deciduous broadleaf forest (Japanese white birch, Japanese oak, and castor aralia in Hokkaido, where incidental damage by the strong Typhoon Songda in 2004 occurred. We also used the biometrical method to demonstrate the CO2 flux within the forest in detail. Damaged trees amounted to 40 % of all trees, and they remained on site where they were not extracted by forest management. Gross primary production (GPP, ecosystem respiration (Re, and net ecosystem production were 1350, 975, and 375 g C m−2 yr−1 before the disturbance and 1262, 1359, and −97 g C m−2 yr−1 2 years after the disturbance, respectively. Before the disturbance, the forest was an evident carbon sink, and it subsequently transformed into a net carbon source. Because of increased light intensity at the forest floor, the leaf area index and biomass of the undergrowth (Sasa kurilensis and S. senanensis increased by factors of 2.4 and 1.7, respectively, in 3 years subsequent to the disturbance. The photosynthesis of Sasa increased rapidly and contributed to the total GPP after the disturbance. The annual GPP only decreased by 6 % just after the disturbance. On the other hand, the annual Re increased by 39 % mainly because of the decomposition of residual coarse-wood debris. The carbon balance after the disturbance was controlled by the new growth and the decomposition of residues. The forest management, which resulted in the dead trees remaining at the study site, strongly affected the carbon balance over the years. When comparing the carbon uptake efficiency at the study site with that at others, including those with various kinds

  11. Food survey. Part A. U. S. agriculture in the U. S. balance of trade. Part B. The world food-population problem

    Energy Technology Data Exchange (ETDEWEB)

    Moulthrop, P.H.

    1976-01-01

    Part A of the paper examines U.S. agriculture with respect to its current and future role in that U.S. trade balance. Part B is a brief look at the world food-population problem. It is appropriate to examine alternatives. One alternative is to simply import oil and pay for it with agricultural exports, security being achieved through diversification of sources of imports. This study examines and identifies the major food issues. An attempt is made to demonstrate that U.S. agricultural exports will probably continue to be a strong positive element in the trade balance for at least the next decade. However, while worldwide demand for food will grow, so will the competition for U.S. agricultural exports. The uncertainties are of significant magnitude that to count on this strategy for the long term seems unwise.

  12. Permafrost and surface energy balance of a polygonal tundra site in Northern Siberia – Part 2: Winter

    Directory of Open Access Journals (Sweden)

    M. Langer

    2010-08-01

    Full Text Available Permafrost is largely determined by the surface energy balance. Its vulnerability to degradation due to climate warming depends on complex soil-atmosphere interactions. This article is the second part of a comprehensive surface energy balance study at a polygonal tundra site in Northern Siberia. It comprises two consecutive winter periods from October 2007 to May 2008 and from October 2008 to January 2009. The surface energy balance is obtained by independent measurements of the radiation budget, the sensible heat flux and the ground heat flux, whereas the latent heat flux is inferred from measurements of the atmospheric turbulence characteristics and a model approach. The measurements reveal that the long-wave radiation is the dominant factor in the surface energy balance. The radiative losses are balanced to about 60% by the ground heat flux and almost 40% by the sensible heat fluxes, whereas the contribution of the latent heat flux is found to be relatively small. The main controlling factors of the surface energy budget are the snow cover, the cloudiness and the soil temperature gradient. Significant spatial differences in the surface energy balance are observed between the tundra soils and a small pond. The heat flux released from the subsurface heat storage is by a factor of two increased at the freezing pond during the entire winter period, whereas differences in the radiation budget are only observed at the end of winter. Inter-annual differences in the surface energy balance are related to differences in snow depth, which substantially affect the temperature evolution at the investigated pond. The obtained results demonstrate the importance of the ground heat flux for the soil-atmosphere energy exchange and reveal high spatial and temporal variabilities in the subsurface heat budget during winter.

  13. Extreme late-summer drought causes neutral annual carbon balance in southwestern ponderosa pine forests and grasslands

    Science.gov (United States)

    Kolb, Thomas; Dore, Sabina; Montes-Helu, Mario

    2013-03-01

    We assessed the impacts of extreme late-summer drought on carbon balance in a semi-arid forest region in Arizona. To understand drought impacts over extremes of forest cover, we measured net ecosystem production (NEP), gross primary production (GPP), and total ecosystem respiration (TER) with eddy covariance over five years (2006-10) at an undisturbed ponderosa pine (Pinus ponderosa) forest and at a former forest converted to grassland by intense burning. Drought shifted annual NEP from a weak source of carbon to the atmosphere to a neutral carbon balance at the burned site and from a carbon sink to neutral at the undisturbed site. Carbon fluxes were particularly sensitive to drought in August. Drought shifted August NEP at the undisturbed site from sink to source because the reduction of GPP (70%) exceeded the reduction of TER (35%). At the burned site drought shifted August NEP from weak source to neutral because the reduction of TER (40%) exceeded the reduction of GPP (20%). These results show that the lack of forest recovery after burning and the exposure of undisturbed forests to late-summer drought reduce carbon sink strength and illustrate the high vulnerability of forest carbon sink strength in the southwest US to predicted increases in intense burning and precipitation variability.

  14. Carbon dioxide stripping in aquaculture. part 1: terminology and reporting

    Science.gov (United States)

    Colt, John; Watten, Barnaby; Pfeiffer, Tim

    2012-01-01

    The removal of carbon dioxide gas in aquacultural systems is much more complex than for oxygen or nitrogen gas because of liquid reactions of carbon dioxide and their kinetics. Almost all published carbon dioxide removal information for aquaculture is based on the apparent removal value after the CO2(aq) + HOH ⇔ H2CO3 reaction has reached equilibrium. The true carbon dioxide removal is larger than the apparent value, especially for high alkalinities and seawater. For low alkalinity freshwaters (carbon dioxide removal.

  15. Increase in Recalcitrant Carbon: a Positive Balance between Stabilization and Priming Effect

    Science.gov (United States)

    Liang, J.; Huo, C.; Shi, Z.; Xia, J.; Luo, Y.

    2014-12-01

    Recalcitrant carbon (C) stored in soils plays a critical role in regulating climate change because of its huge amount and relatively low turnover rate. Positive priming effect by increased labile C inputs could lead to more recalcitrant C release to the atmosphere. However, the stabilization of the newly added labile C has received much less attention. As a result, the quantitative balance between the stabilization and priming and consequently changes in recalcitrant C are still unclear. In this study, incubation data of different soils (i.e., forest, grassland, cropland, and vertisol) with isotope-labeled labile substrate additions were collected. An alternative version of the Introductory Carbon Balance Model (ICBM) with stabilization and positive priming effect was used to simulate the C dynamics during the incubation and then run forward for ten years. The results showed that at the end of incubation, an equivalent of 5.45 - 26.1% of added C was primed from the original SOM for the four soils. Meanwhile, 40.9 - 70.7% of added C was stabilized, leading to a net increase in recalcitrant C by an equivalent of 18.0 - 50.0% of added C. After running model for ten years, the recalcitrant C was greater with than without initial labile C addition by an equivalent of 33.0, 2.01, 21.6, and 0.62% of added C for the forest, grassland, cropland and vertisol, respectively. Our results suggest that stabilization overcompensates the C loss induced by positive priming effect, indicating that stimulated labile C input under CO2 enrichment may increase the recalcitrant C storage in soils, and consequently dampen the further increase in atmospheric CO2 concentrations and climate change. The results also suggest that both stabilization and positive priming effect may vary among ecosystems and with the type and amount of added substrates. To better quantify the net change in recalcitrant C and thus long-term soil C storage, comprehensive studies on the effects of soil type, added

  16. Effect of forest drainage on the carbon balance and greenhouse impact of Finnish peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Laine, J.; Minkkinen, K.; Laiho, R. [Helsinki Univ. (Finland). Dept. of Forest Ecology

    1996-12-31

    The aim of this project is to produce an estimate of the change in the biomass and peat carbon stores arising from the drainage of peatlands for forestry, and of the change of greenhouse impact of these ecosystems. The study shows that the subsidence of mire surfaces due to drainage has been relatively small, on average about 20 cm. The observed increase in bulk density after drainage is caused by the physical compression of peat and the post-drainage input of organic material in the form of litter production from the above and below ground parts of the tree layer. Oxidative decay of organic matter may have further increased the compaction of peat, especially in fertile sites. When the changes in peat and vegetation carbon stores are summed up, it seems that, within the site types studied, the total impact of drainage to the ecosystem carbon store is close to zero on the nutrient rich sites and clearly positive on the poorer types. Water level drawdown in peatlands after drainage for forestry appears to decrease the greenhouse impact at least for a few hundred years. The estimated changes in all three emission components (CH{sub 4} emissions, CO{sub 2} sink from peatland and CO{sub 2} sequestered in trees) reduce the radiative forcing by approximately similar amounts

  17. Energy Crops and their Implications on Soil Carbon Sequestration, Surface Energy and Water Balance

    Science.gov (United States)

    Song, Y.; Barman, R.; Jain, A. K.

    2011-12-01

    The quest to meet growing energy demand with low greenhouse gas emissions has increased attention on the potential of existing and advanced biomass energy crops. Potential energy crops include row crops such as corn, and perennial grasses such as switchgrass. However, a massive expansion of bioenergy crops raises many questions such as: how and where to grow energy crops; and what will be the impacts of growing large scale biofuel crops on the terrestrial hydrological cycle, the surface energy budget, soil carbon sequestration and the concurrent effects on the climate system. An integrated modeling system is being developed with in the framework of a land surface model, the Integrated Science Assessment Model (ISAM), and being applied to address these questions.This framework accounts for the biophysical, physiological and biogeochemical systems governing important processes that regulate crop growth including water, energy and nutrient cycles within the soil-plant-atmosphere system. One row crop (Corn) and two energy crops (Switchgrass and Miscanthus) are studied in current framework. Dynamic phenology processes and parameters for simulating each crop have been developed using observed data from a north to south gradient of field trial sites. This study will specifically focus on the agricultural regions in the US and in Europe. The potential productivity of these three crops will be assessed in terms of carbon sequestration, surface energy and water balance and their spatial variability. This study will help to quantify the importance of various environmental aspects towards modeling bioenergy crops and to better understand the spatial and temporal dynamics of bioenergy crop yields.

  18. Roles of urban vegetation on balance of carbon and oxygen in Guangzhou, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The plant biomass and net primary production(NPP) of urban vegetation in Guangzhou were estimated by dimension analysis, treetruck volume, and harvest methods as well as relationship between biomass and NPP and so on.The biomass and NPP were respectively2875150t and 1058122 t/a.They were respectively 392495t and 64948 t/a in the built-up area and 2482655t and 993147 t/a in the unbuilt-uparea.It would make plant biomass, especially NPP decline obviously, if the unbuilt-up area were changed to the built-up area.The carboncontent of plant was 1328649 for the total and 13.78 t/hm2 for the mean, and amounts of carbon fixed and oxygen made by urban vegetationwere respectively 4.80 t/(hm2 @a) and 12.79 t/(hm2 @a) for the mean and 462624 t/a and 1232430 t/a for the total, which were equal to 1.45times and 1.04 times of those by human breathing.However, they were only equal to 7.61% and 4.97% of amount of carbon released andoxygen consumption in urban Guangzhou.The biomass and NPP of urban vegetation in Guangzhou only corresponded to 7.8% and 47.3% ofthose of southern subtropical evergreen broad-leaf forest in Dinghu Mountain.Therefore, the roles of Guangzhou urban vegetation in balance ofcarbon and oxygen would be increased greatly if it could be conserved and improved in some way.

  19. How to do an energy balance in the PRESENCE of chemical reaction - Part 1

    OpenAIRE

    Fernandez-Torres, Maria J.

    2013-01-01

    A solved example for the determination of the increment in enthalpy for the energy balances for open systems in the context of chemical engineering is presented. The example shows how to tackle this kind of problems when it has been decided not to make use of the enthalpy of the reaction. The substances elements will be used as reference state.

  20. How to do an energy balance in the PRESENCE of chemical reaction - part 2

    OpenAIRE

    Fernandez-Torres, Maria J.

    2013-01-01

    A solved example for the determination of the increment in enthalpy for the energy balances for open systems in the context of chemical engineering is presented. The example shows how to tackle this kind of problems when it has been decided to make use of the enthalpy of the reaction.

  1. Carbon and nitrogen balance of leaf-eating sesarmid crabs ( Neoepisesarma versicolor) offered different food sources

    Science.gov (United States)

    Thongtham, Nalinee; Kristensen, Erik

    2005-10-01

    Carbon and nitrogen budgets for the leaf-eating crab, Neoepisesarma versicolor, were established for individuals living on pure leaf diets. Crabs were fed fresh (green), senescent (yellow) and partly degraded (brown) leaves of the mangrove tree Rhizophora apiculata. Ingestion, egestion and metabolic loss of carbon and nitrogen were determined from laboratory experiments. In addition, bacterial abundance in various compartments of the crabs' digestive tract was enumerated after dissection of live individuals. Ingestion and egestion rates (in terms of dry weight) were highest, while the assimilation efficiency was poorest for crabs fed on brown leaves. The low assimilation efficiency was more than counteracted by the high ingestion rate providing more carbon for growth than for crabs fed green and yellow leaves. In any case, the results show that all types of leaves can provide adequate carbon while nitrogen was insufficient to support both maintenance (yellow leaves) and growth (green, yellow and brown leaves). Leaf-eating crabs must therefore obtain supplementary nitrogen by other means in order to meet their nitrogen requirement. Three hypotheses were evaluated: (1) crabs supplement their diet with bacteria and benthic microalgae by ingesting own faeces and/or selective grazing at the sediment surface; (2) assimilation of symbiotic nitrogen-fixing bacteria in the crabs' own intestinal system; and (3) nitrogen storage following occasional feeding on animal tissues (e.g. meiofauna and carcasses). It appears that hypothesis 1 is of limited importance for N. versicolor since faeces and sediment can only supply a minor fraction of the missing nitrogen due to physical constraints on the amount of material the crabs can consume. Hypothesis 2 can be ruled out because tests showed no nitrogen fixation activity in the intestinal system of N. versicolor. It is therefore likely that leaf-eating crabs provide most of their nitrogen requirement from intracellular deposits

  2. Crop Management Effects on the Energy and Carbon Balances of Maize Stover-Based Ethanol Production

    Directory of Open Access Journals (Sweden)

    Prem Woli

    2014-12-01

    Full Text Available This study was conducted to identify the crop management options—the combinations of various cultivars, irrigation amounts, planting dates, and soils—that would maximize the energy sustainability and eco-friendliness of maize (Zea mays L. stover-based ethanol production systems in the Mississippi Delta. Stover yields simulated with CERES-Maize were used to compute net energy value (NEV and carbon credit balance (CCB, the indicators of sustainability and eco-friendliness of ethanol production, respectively, for various scenarios. As the results showed, deeper soils with higher water holding capacities had larger NEV and CCB values. Both NEV and CCB had sigmoid relationships with irrigation amount and planting date and could be maximized by planting the crop during the optimum planting window. Stover yield had positive effects on NEV and CCB, whereas travel distance had negative. The influence of stover yield was larger than that of travel distance, indicating that increasing feedstock yields should be emphasized over reducing travel distance. The NEV and CCB values indicated that stover-based ethanol production in the Mississippi Delta is sustainable and environmentally friendly. The study demonstrated that the energy sustainability and eco-friendliness of maize stover-based ethanol production could be increased with alternative crop management options.

  3. The modeled effects of fire on carbon balance and vegetation abundance in Alaskan tundra

    Science.gov (United States)

    Dietze, M. C.; Davidson, C. D.; Kelly, R.; Higuera, P. E.; Hu, F.

    2012-12-01

    Arctic climate is warming at a rate disproportionately faster than the rest of the world. Changes have been observed within the tundra that are attributed to this trend, including active layer thickening, shrub land expansion, and increases in fire frequency. Whether tundra remains a global net sink of carbon could depend upon the effects of fire on vegetation, specifically concerning the speed at which vegetation reestablishes, the stimulation of growth after fire, and the changes that occur in species composition during succession. While rapid regeneration of graminoid vegetation favors the spread of this functional type in early succession, late succession appears to favor shrub vegetation at abundances greater than those observed before fire. Possible reasons for this latter observation include changes in albedo, soil insulation, and soil moisture regimes. Here we investigate the course of succession after fire disturbance within tundra ecosystems, and the mechanisms involved. A series of simulated burn experiments were conducted on the burn site left by the 2007 Anaktuvuk River fire to access the behavior of the Ecosystem Demography model v2.2 (ED2) in the simulation of fire on the tundra. The land surface sub-model within ED is modified to improve simulate permafrost through the effects of an increased soil-column depth, a peat texture class, and the effects of wind compaction and depth hoar on snow density. Parameterization is conducted through Bayesian techniques used to constrain parameter distributions based upon data from a literature survey, field measurements at Toolik Lake, Alaska, and a data assimilation over three datasets. At each step, priority was assigned to measurements that could constrain parameters that account for the greatest explained variance in model output as determined through sensitivity analysis. Following parameterization, a series of simulations were performed to gauge the suitability of the model in predicting carbon balance and

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

    Science.gov (United States)

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

    2014-05-01

    needed by the organisms to build up biomass. The predicted requirement for nitrogen ranges from 3.5 to 34 Tg a-1, again being in a reasonable range compared to the data analysis approach. In experimental field studies (3rd approach), we analyzed the net primary production of biological soil crusts, i.e. one major group of cryptogamic covers. The microclimatic conditions (water status, temperature, light intensity) of different types of biological soil crusts were monitored at 5-minute intervals over a whole year. Conducting a factorial analysis of CO2 gas exchange of the crusts in the lab, we obtained the net photosynthesis or respiration rate for all microclimatic conditions encountered in the field. The latter results were combined with the microclimate data, assigning CO2 gas exchange values to each microclimate measurement tuple. Integration over the year resulted in an annual carbon fixation of ~5 g m-2 a-1, being nearly identical to the numbers obtained during the data analysis approach. In summary, our three different approaches clearly revealed that cryptogamic covers have a considerable effect on the global terrestrial C and N cycle, which must not be neglected in global carbon and nitrogen balances.

  5. The impact of Saharan dust and black carbon on albedo and long-term glacier mass balance

    Directory of Open Access Journals (Sweden)

    J. Gabbi

    2015-02-01

    Full Text Available Light-absorbing impurities in snow and ice control glacier melt as shortwave radiation represents the main component of the surface energy balance. Here, we investigate the long-term effect of snow impurities, i.e. Saharan dust and black carbon (BC, on albedo and glacier mass balance. The analysis was performed over the period 1914–2014 for two sites on Claridenfirn, Swiss Alps, where an outstanding 100 year record of seasonal mass balance measurements is available. Information on atmospheric deposition of mineral dust and BC over the last century was retrieved from two firn/ice cores of high-alpine sites. A combined mass balance and snow/firn layer model was employed to assess the dust/BC-albedo feedback. Compared to pure snow conditions, the presence of Saharan dust and BC lowered the mean annual albedo by 0.04–0.06 and increased melt by 15–19% on average depending on the location on the glacier. BC clearly dominated absorption which is about three times higher than that of mineral dust. The upper site has experienced mainly positive mass balances and impurity layers were continuously buried whereas at the lower site, surface albedo was more strongly influenced by re-exposure of dust-enriched layers due to frequent years with negative mass balances.

  6. Botswana water and surface energy balance research program. Part 2: Large scale moisture and passive microwaves

    Science.gov (United States)

    Vandegriend, A. A.; Owe, M.; Chang, A. T. C.

    1992-01-01

    The Botswana water and surface energy balance research program was developed to study and evaluate the integrated use of multispectral satellite remote sensing for monitoring the hydrological status of the Earth's surface. The research program consisted of two major, mutually related components: a surface energy balance modeling component, built around an extensive field campaign; and a passive microwave research component which consisted of a retrospective study of large scale moisture conditions and Nimbus scanning multichannel microwave radiometer microwave signatures. The integrated approach of both components are explained in general and activities performed within the passive microwave research component are summarized. The microwave theory is discussed taking into account: soil dielectric constant, emissivity, soil roughness effects, vegetation effects, optical depth, single scattering albedo, and wavelength effects. The study site is described. The soil moisture data and its processing are considered. The relation between observed large scale soil moisture and normalized brightness temperatures is discussed. Vegetation characteristics and inverse modeling of soil emissivity is considered.

  7. Counting carbon in the marketplace: Part 1 - overview paper

    DEFF Research Database (Denmark)

    Bolwig, Simon; Gibbon, Peter

    are often referred to as ―product carbon footprints‖ (PCFs), where ―carbon footprint‖ is the total amount of GHGs produced for a given activity and ―product‖ is any good or service that is marketed. PCFs are thus distinct from GHG assessments performed at the level of projects, corporations, supply chains...

  8. The impact of Saharan dust and black carbon on albedo and long-term mass balance of an Alpine glacier

    Directory of Open Access Journals (Sweden)

    J. Gabbi

    2015-07-01

    Full Text Available Light-absorbing impurities in snow and ice control glacier melt as shortwave radiation represents the main component of the surface energy balance. Here, we investigate the long-term effect of snow impurities, i.e., mineral dust and black carbon (BC, on albedo and glacier mass balance. The analysis was performed over the period 1914–2014 for two sites on Claridenfirn, Swiss Alps, where an outstanding 100-year record of seasonal mass balance measurements is available. Information on atmospheric deposition of mineral dust and BC over the last century was retrieved from two firn/ice cores of high-alpine sites. A combined mass balance and snow/firn layer model was employed to assess the effects of melt and accumulation processes on the impurity concentration at the surface and thus on albedo and glacier mass balance. Compared to pure snow conditions, the presence of Saharan dust and BC lowered the mean annual albedo by 0.04–0.06 depending on the location on the glacier. Consequently, annual melt was increased by 15–19 %, and the mean annual mass balance was reduced by about 280–490 mm w.e. BC clearly dominated absorption which is about 3 times higher than that of mineral dust. The upper site has experienced mainly positive mass balances and impurity layers were continuously buried whereas at the lower site, surface albedo was more strongly influenced by re-exposure of dust and BC-enriched layers due to frequent years with negative mass balances.

  9. The impact of Saharan dust and black carbon on albedo and long-term mass balance of an Alpine glacier

    Science.gov (United States)

    Gabbi, J.; Huss, M.; Bauder, A.; Cao, F.; Schwikowski, M.

    2015-07-01

    Light-absorbing impurities in snow and ice control glacier melt as shortwave radiation represents the main component of the surface energy balance. Here, we investigate the long-term effect of snow impurities, i.e., mineral dust and black carbon (BC), on albedo and glacier mass balance. The analysis was performed over the period 1914-2014 for two sites on Claridenfirn, Swiss Alps, where an outstanding 100-year record of seasonal mass balance measurements is available. Information on atmospheric deposition of mineral dust and BC over the last century was retrieved from two firn/ice cores of high-alpine sites. A combined mass balance and snow/firn layer model was employed to assess the effects of melt and accumulation processes on the impurity concentration at the surface and thus on albedo and glacier mass balance. Compared to pure snow conditions, the presence of Saharan dust and BC lowered the mean annual albedo by 0.04-0.06 depending on the location on the glacier. Consequently, annual melt was increased by 15-19 %, and the mean annual mass balance was reduced by about 280-490 mm w.e. BC clearly dominated absorption which is about 3 times higher than that of mineral dust. The upper site has experienced mainly positive mass balances and impurity layers were continuously buried whereas at the lower site, surface albedo was more strongly influenced by re-exposure of dust and BC-enriched layers due to frequent years with negative mass balances.

  10. Interactions between biomass energy technologies and nutrient and carbon balances at the farm level

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, Uffe; Molt Petersen, B. [Danish Inst. of Agricultural Science, Dept. of Agroecology, Tjele (Denmark)

    2006-08-15

    Biomass energy is by far the largest renewable energy source in the world (IEA Renewable information (www.iea.org)). Biomass utilisation is closely linked to management and sustainability issues of forestry and agriculture. Carbon is extracted from forests and agriculture to bioenergy facilities, from where it is partly or fully emitted as CO{sub 2} and thus no longer available for sustaining soil organic matter content. Nutrients are extracted as well and, depending of the conversion technology, they may be recycled to farmland or lost as gaseous emissions. Thus, we must be able to describe these effects, and to suggest strategies to alleviate adverse effects on farm sustainability and on the environment. By choosing intelligent combinations of cropping systems and energy conversion technologies, win-win solutions may be achieved. This paper illustrates, via three cases, some agricultural impacts of choice of biomass technology and describes an intriguing possibility for recycling municipal or industrial wastes through the bioenergy chain. (au)

  11. Land-use change to bioenergy production in Europe: implications for the greenhouse gas balance and soil carbon

    DEFF Research Database (Denmark)

    Don, Axel; Osborne, Bruce; Hastings, Astley

    2012-01-01

    for Miscanthus). However, there was no positive or even negative effects on the C balance if energy crops are established on former grassland. Increased bioenergy production may also result in direct and indirect land-use changes with potential high C losses when native vegetation is converted to annual crops....... Although dedicated perennial energy crops have a high potential to improve the GHG balance of bioenergy production, several agronomic and economic constraints still have to be overcome........ These greenhouse gases (GHGs) need to be included into the carbon footprint calculation of different bioenergy crops under a range of soil conditions and management practices. This review compiles existing knowledge on agronomic and environmental constraints and GHG balances of the major European bioenergy crops...

  12. Greenhouse gases inventory and carbon balance of two dairy systems obtained from two methane-estimation methods.

    Science.gov (United States)

    Cunha, C S; Lopes, N L; Veloso, C M; Jacovine, L A G; Tomich, T R; Pereira, L G R; Marcondes, M I

    2016-11-15

    The adoption of carbon inventories for dairy farms in tropical countries based on models developed from animals and diets of temperate climates is questionable. Thus, the objectives of this study were to estimate enteric methane (CH4) emissions through the SF6 tracer gas technique and through equations proposed by the Intergovernmental Panel on Climate Change (IPCC) Tier 2 and to calculate the inventory of greenhouse gas (GHG) emissions from two dairy systems. In addition, the carbon balance of these properties was estimated using enteric CH4 emissions obtained using both methodologies. In trial 1, the CH4 emissions were estimated from seven Holstein dairy cattle categories based on the SF6 tracer gas technique and on IPCC equations. The categories used in the study were prepubertal heifers (n=6); pubertal heifers (n=4); pregnant heifers (n=5); high-producing (n=6); medium-producing (n=5); low-producing (n=4) and dry cows (n=5). Enteric methane emission was higher for the category comprising prepubertal heifers when estimated by the equations proposed by the IPCC Tier 2. However, higher CH4 emissions were estimated by the SF6 technique in the categories including medium- and high-producing cows and dry cows. Pubertal heifers, pregnant heifers, and low-producing cows had equal CH4 emissions as estimated by both methods. In trial 2, two dairy farms were monitored for one year to identify all activities that contributed in any way to GHG emissions. The total emission from Farm 1 was 3.21t CO2e/animal/yr, of which 1.63t corresponded to enteric CH4. Farm 2 emitted 3.18t CO2e/animal/yr, with 1.70t of enteric CH4. IPCC estimations can underestimate CH4 emissions from some categories while overestimate others. However, considering the whole property, these discrepancies are offset and we would submit that the equations suggested by the IPCC properly estimate the total CH4 emission and carbon balance of the properties. Thus, the IPCC equations should be utilized with

  13. The Impact of a Mild Sub-Critical Hydrothermal Carbonization Pretreatment on Umbila Wood. A Mass and Energy Balance Perspective

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Cuvilas

    2015-03-01

    Full Text Available Over the last years, the pretreatment of biomass as a source of energy has become one of the most important steps of biomass conversion. In this work the effect of a mild subcritical hydrothermal carbonization of a tropical woody biomass was studied. Results indicate considerable change in carbon content from 52.78% to 65.1%, reduction of oxygen content from 41.14% to 28.72% and ash slagging and fouling potential. Even though decarboxylation, decarbonylation and dehydration reactions take place, dehydration is the one that prevails. The mass and energy balance was affected by the treatment conditions than the severity of the treatment.

  14. Influence of oxygen on alcoholic fermentation by a wine strain of Torulaspora delbrueckii: kinetics and carbon mass balance.

    Science.gov (United States)

    Brandam, Cédric; Lai, Quoc Phong; Julien-Ortiz, Anne; Taillandier, Patricia

    2013-01-01

    Torulaspora delbrueckii metabolism was assessed in a synthetic culture medium similar to grape must under various conditions: no aeration and three different oxygen feeds, in order to determine the effect of oxygen on metabolism. Carbon and nitrogen mass balances were calculated to quantify metabolic fluxes. The effect of oxygen was to decrease the flux of carbon going into the fermentation pathway in favor of growth. In the absence of aeration, higher amounts of glycerol were produced, probably to maintain the redox balance. The oxygen requirement of this strain was high, since even for the highest air supply oxygen became limiting after 24 h. Nevertheless, this strain developed well in the absence of oxygen and consumed 220 g/L of sugars (glucose/fructose) in 166 h at 20 °C, giving a good ethanol yield (0.50 g/g).

  15. Assessment of annual balances of mining enterprises by ratio analysis. Part I: Discussion of basic ratios

    Energy Technology Data Exchange (ETDEWEB)

    Jurdziak, L.

    1992-08-01

    Discusses the basic financial ratios used to assess the financial standing of a mining enterprise: liquidity, leverage/gearing, activity and profitability ratios, cash flow to the current portion of long-term-debt ratio, etc. It is recommended that for mining enterprises, being high risk firms, the latter ratio be over 0.33:1 (the produced cash flow should cover the total debts in less than three years). The method described makes use of the ratio of various items of an annual balance in order to assess the value and credit worthiness of a mining enterprise. The possibility of a take-over, and investment risk are also evaluated. 11 refs.

  16. TOR Signaling Promotes Accumulation of BZR1 to Balance Growth with Carbon Availability in Arabidopsis.

    Science.gov (United States)

    Zhang, Zhenzhen; Zhu, Jia-Ying; Roh, Jeehee; Marchive, Chloé; Kim, Seong-Ki; Meyer, Christian; Sun, Yu; Wang, Wenfei; Wang, Zhi-Yong

    2016-07-25

    For maintenance of cellular homeostasis, the actions of growth-promoting hormones must be attenuated when nutrient and energy become limiting. The molecular mechanisms that coordinate hormone-dependent growth responses with nutrient availability remain poorly understood in plants [1, 2]. The target of rapamycin (TOR) kinase is an evolutionarily conserved master regulator that integrates nutrient and energy signaling to regulate growth and homeostasis in both animals and plants [3-7]. Here, we show that sugar signaling through TOR controls the accumulation of the brassinosteroid (BR)-signaling transcription factor BZR1, which is essential for growth promotion by multiple hormonal and environmental signals [8-11]. Starvation, caused by shifting of light-grown Arabidopsis seedlings into darkness, as well as inhibition of TOR by inducible RNAi, led to plant growth arrest and reduced expression of BR-responsive genes. The growth arrest caused by TOR inactivation was partially recovered by BR treatment and the gain-of-function mutation bzr1-1D, which causes accumulation of active forms of BZR1 [12]. Exogenous sugar promoted BZR1 accumulation and seedling growth, but such sugar effects were largely abolished by inactivation of TOR, whereas the effect of TOR inactivation on BZR1 degradation is abolished by inhibition of autophagy and by the bzr1-1D mutation. These results indicate that cellular starvation leads sequentially to TOR inactivation, autophagy, and BZR1 degradation. Such regulation of BZR1 accumulation by glucose-TOR signaling allows carbon availability to control the growth promotion hormonal programs, ensuring supply-demand balance in plant growth.

  17. Towards operational remote sensing of forest carbon balance across Northern Europe

    Directory of Open Access Journals (Sweden)

    P. Olofsson

    2008-05-01

    Full Text Available Monthly averages of ecosystem respiration (ER, gross primary production (GPP and net ecosystem exchange (NEE over Scandinavian forest sites were estimated using regression models driven by air temperature (AT, absorbed photosynthetically active radiation (APAR and vegetation indices. The models were constructed and evaluated using satellite data from Terra/MODIS and measured data collected at seven flux tower sites in northern Europe. Data used for model construction was excluded from the evaluation. Relationships between ground measured variables and the independent variables were investigated.

    It was found that the enhanced vegetation index (EVI at 250 m resolution was highly noisy for the coniferous sites, and hence, 1 km EVI was used for the analysis. Linear relationships between EVI and the biophysical variables were found: correlation coefficients between EVI and GPP, NEE, and AT ranged from 0.90 to 0.79 for the deciduous data, and from 0.85 to 0.67 for the coniferous data. Due to saturation, there were no linear relationships between normalized difference vegetation index (NDVI and the ground measured parameters found at any site. APAR correlated better with the parameters in question than the vegetation indices. Modeled GPP and ER were in good agreement with measured values, with more than 90% of the variation in measured GPP and ER being explained by the coniferous models. The site-specific respiration rate at 10°C (R10 was needed for describing the ER variation between sites. Even though monthly NEE was modeled with less accuracy than GPP, 61% and 75% (dec. and con., respectively of the variation in the measured time series was explained by the model. These results are important for moving towards operational remote sensing of forest carbon balance across Northern Europe.

  18. A carbon balance model of peach tree growth and development for studying the pruning response.

    Science.gov (United States)

    Génard, Michel; Pagès, Loïc; Kervella, Jocelyne

    1998-06-01

    We modeled tree responses to pruning on the basis of growth rules established on unpruned trees and a simple principle governing root-shoot interactions. The model, which integrates architectural and ecophysiological approaches, distinguishes four types of anatomical organs in a tree: rootstock, main axis, secondary axes and new roots. Tree structure is described by the position of secondary axes on the main axis. The main processes considered are plastochronal activity, branching, assimilate production, respiration and assimilate partitioning. Growth and development rules were based on measurements of two unpruned trees. The model was used to simulate growth of peach trees (Prunus persica (L.) Batsch) in their first growing season. Assuming that the equilibrium between roots and shoots tends to be restored after pruning, the response to removal of the main axis above the twentieth internode in mid-July was simulated and compared to the response measured in three pruned trees. The model fit the unpruned tree data reasonably well and predicted the main traits of tree behavior after pruning. Dry matter growth of the secondary axes of pruned trees was increased so that shoot seasonal carbon balance was hardly modified by pruning. Rhythmicity of growth was enhanced by pruning, and might result from variations induced in the root:shoot ratio. Variation in pruning severity had greater effects than variation in pruning date. A sensitivity analysis indicated that: (1) root-shoot partitioning was a critical process of the model; (2) tree growth was mainly dependent on assimilate availability; and (3) tree shape was highly dependent on the branching process.

  19. Earthworms and the soil greenhouse gas balance

    NARCIS (Netherlands)

    Lubbers, I.M.

    2014-01-01

      Earthworms play an essential part in determining the greenhouse gas (GHG) balance of soils worldwide. Their activity affects both biotic and abiotic soil properties, which in turn influence soil GHG emissions, carbon (C) sequestration and plant growth. Yet, the balance of earthworms stimulat

  20. Carbon balance of mountain forests close to timberline - Effect of encroachment

    Science.gov (United States)

    Jandl, Robert; Jandl, Nathalia

    2013-04-01

    Mountain forests are strongly affected by climate change effects. The migration of trees into alpine pastures affects the local carbon budget. The soils are accruing carbon and the tree biomass further enhances the local carbon pool. In a simulation exercise combining a forest growth model and a soil carbon model we followed the temporal trend of the ecosystem carbon pool under different management scenarios and climate scenarios. -- The data evaluation is currently in progress.

  1. In search of work/life balance: trainee perspectives on part-time obstetrics and gynaecology specialist training

    Directory of Open Access Journals (Sweden)

    Henry Amanda

    2012-01-01

    Full Text Available Abstract Background Part-time training (PTT is accessed by approximately 10% of Australian obstetrics and gynaecology trainees, a small but increasing minority which reflects the growing demand for improved work/life balance amongst the Australian medical workforce. This survey reports the attitudes and experiences of both full-time and part-time trainees to PTT. Methods An email-based anonymous survey was sent to all Australian obstetrics and gynaecology trainees in April 2009, collecting demographic and training status data, data on personal experiences of PTT and/or trainees, and attitudes towards PTT. Results 105 responses were received (20% response rate. These indicated strong support (90% from both full-time (FT and part-time (PT trainees for the availability of PTT. PT trainees were significantly more likely than FT trainees to be female with children. Improved morale was seen as a particular advantage of PTT; decreased continuity of care as a disadvantage. Conclusions Although limited by poor response rate, both PT and FT Australian obstetric trainees were supportive of part-time training. Both groups recognised important advantages and disadvantages of this mode of training. Currently, part-time training is accessed primarily by female trainees with family responsibilities, with many more trainees considering part-time training than the number that access it.

  2. Effect of initial glucose concentrations on carbon material and energy balances in hydrogen-producing Clostridium tyrobutyricum JM1.

    Science.gov (United States)

    Jo, Ji Hye; Lee, Dae Sung; Kim, Junhoon; Park, Jong Moon

    2009-03-01

    The carbon metabolism of newly isolated Clostridium tyrobutyricum JM1 was investigated at varying initial glucose concentrations (27.8-333.6mM). Because an understanding of metabolic regulations was required to provide guidance for further effective metabolic design or optimization, in this case, maximizing hydrogen production, carbon material, and energy balances by C. tyrobutyricum JM1 were determined and applied in anaerobic glucose metabolism. The overall carbon distribution suggested that initial glucose concentrations had strong influence on the stoichiometric coefficients of products and the molar production of ATP on the formation of biomass. C. tyrobutyricum JM1 had a high capacity for hydrogen production at the initial glucose concentration of 222.4 mM with high concentrations of acetate and butyrate.

  3. Effects of climate variability and functional changes on the interannual variation of the carbon balance in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Wu, Jian; van der Linden, Leon; Lasslop, G.;

    2012-01-01

    The net ecosystem exchange of CO2 (NEE) between the atmosphere and a temperate beech forest showed a significant interannual variation (IAV) and a decadal trend of increasing carbon uptake (Pilegaard et al., 2011). The objectives of this study were to evaluate to what extent and at which temporal...... scale, direct climatic variability and changes in ecosystem functional properties regulated the IAV of the carbon balance at this site. Correlation analysis showed that the sensitivity of carbon fluxes to climatic variability was significantly higher at shorter than at longer time scales and changed...... climatic effects from changes in ecosystem functioning (Richardson et al., 2007) by employing the semi empirical model published by Lasslop et al. (2010b). Fitting the model in short moving windows enabled large flexibility to adjust the parameters to the seasonal course of the ecosystem functional state...

  4. Study plan: Assessing ecosystem services and carbon balance in support of land management at the Great Dismal Swamp, Pocosin Lakes, and Alligator River National Wildlife Refuges

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This study plan describes a collaborative research project to assess ecosystem services and estimate carbon balance in relation to water management and other...

  5. Effects of Permafrost Thaw on Net Ecosystem Carbon Balance in a Subarctic Peatland

    Science.gov (United States)

    Wang, Z.; Roulet, N. T.; Moore, T. R.

    2014-12-01

    This research is to assess changes in net ecosystem carbon balance (NECB) with permafrost thaw in northern peatland: in particular how changes in C biogeochemistry influence NECB. Thawed transects associated with varying stages of permafrost thaw: from palsas with intact permafrost (P), through edge of palsa (EP), dry lawn (DL), wet lawn (WL), edge of thawed pond (ET), pond sedges (PS), to several thawed ponds (TP) in a subarctic peatland in northern Quebec were sampled in the snow free seasons of 2013 and 2014. The exchange of CO2 and CH4, vegetation, dissolved organic C (DOC) concentration and biodegradability, active layer depth, air and peat temperatures, water table depth (WT), pH, and conductivity were measured. Peat temperatures were quite similar among different locations, but the WT decreased significantly along the transect creating varied environmental conditions that supporting different plant communities. From dry to wet area, vegetation abundance and biomass showed reductions of shrubs and lichens, and increases of Sphagnum, grasses and sedges. Pore water pH increased from dry to wet area, and conductivity slightly decreased. Wet thaw area WL, ET and PS had relatively higher season gross ecosystem production (GEP) and higher season ecosystem respiration (ER), but relative similar net ecosystem CO2 exchange (NEE). Only TP had a significant higher positive season NEE. Palsa was the only CH4 sink, and quite high CH4 emissions were found after it thawed. CH4-C release significantly increased from dry to wet in thawed area, which even several times bigger than total C exchange in ET and PS. Generally, wet area had higher DOC concentration and higher DOC biodegradability indicated by lower SUVA254 (except PS which received great influence from pond). All components in the NECB (GEP, ER, CH4, DOC) increased significantly in magnitude from palsa to wet thawed area, and ecosystem C sink turned into source as palsa thawed into PS and TP. These results

  6. Multivariate Curve Resolution and Carbon Balance Constraint to Unravel FTIR Spectra from Fed-Batch Fermentation Samples

    Directory of Open Access Journals (Sweden)

    Dennis Vier

    2017-01-01

    Full Text Available The current work investigates the capability of a tailored multivariate curve resolution–alternating least squares (MCR-ALS algorithm to analyse glucose, phosphate, ammonium and acetate dynamics simultaneously in an E. coli BL21 fed-batch fermentation. The high-cell-density (HCDC process is monitored by ex situ online attenuated total reflection (ATR Fourier transform infrared (FTIR spectroscopy and several in situ online process sensors. This approach efficiently utilises automatically generated process data to reduce the time and cost consuming reference measurement effort for multivariate calibration. To determine metabolite concentrations with accuracies between ±0.19 and ±0.96·gL−l, the presented utilisation needs primarily—besides online sensor measurements—single FTIR measurements for each of the components of interest. The ambiguities in alternating least squares solutions for concentration estimation are reduced by the insertion of analytical process knowledge primarily in the form of elementary carbon mass balances. Thus, in this way, the established idea of mass balance constraints in MCR combines with the consistency check of measured data by carbon balances, as commonly applied in bioprocess engineering. The constraints are calculated based on online process data and theoretical assumptions. This increased calculation effort is able to replace, to a large extent, the need for manually conducted quantitative chemical analysis, leads to good estimations of concentration profiles and a better process understanding.

  7. The response of dissolved organic carbon (DOC) and the ecosystem carbon balance to experimental drought in a temperate shrubland

    DEFF Research Database (Denmark)

    Sowerby, A.; Emmett, B.A.; Williams, D.;

    2010-01-01

    Climate change has been proposed as a driver of carbon (C) loss from the large pool of C held in soils. Aqueous (dissolved organic carbon, DOC) and gaseous (soil respiration or net ecosystem CO2 exchange) forms of C loss from soils have been considered. Under some climate change scenarios, gaseou...

  8. Fluidized-bed reactor model with generalized particle balances. Part 2. Coal combustion application

    Energy Technology Data Exchange (ETDEWEB)

    Overturf, B.W.; Reklaitis, G.V.

    1983-09-01

    In the second part, the model is applied to the study of an atmospheric fluidized-bed coal combustor. Case studies are investigated to show the effects of a number of parameters. Proper representation of the grid region and use of actual feed distributions are shown to be essential to the prediction of combustor performance. Better particle elutriation and single-particle combustion sub-models are found to be key requirements for improved combustor modelling.

  9. Dual Tuning of Biomass-Derived Hierarchical Carbon Nanostructures for Supercapacitors: the Role of Balanced Meso/Microporosity and Graphene

    Science.gov (United States)

    Zhu, Zhengju; Jiang, Hao; Guo, Shaojun; Cheng, Qilin; Hu, Yanjie; Li, Chunzhong

    2015-01-01

    Rational design of advanced carbon nanomaterials with a balanced mesoporosity to microporosity is highly desirable for achieving high energy/power density for supercapacitors because the mesopore can allow better transport pathways for the solvated ions of larger than 1 nm. Inspired by the inherent meso/macroporous architecture and huge absorption ability to aqueous solution of auricularia biomass, we demonstrate a new biomass-derived synthesis process for the three-dimensional (3D) few-layered graphene nanosheets incorporated hierarchical porous carbon (GHPC) nanohybrids. The as-prepared GHPC nanohybrids possess a balanced mesoporosity to microporosity with much improved conductivity, which is highly desirable for achieving high energy/power density for supercapacitors. As we predicted, they delivered a high specific capacitance of 256 F g−1 at 1 A g−1 with excellent rate capability (120 F g−1 at 50 A g−1) and long cycle life (92% capacity retention after 10000 cycles) for symmetric supercapacitors in 1 M H2SO4. Based on the as-obtained carbon materials, a flexible and all-solid-state supercapacitor was also assembled, which can be fully recharged within 10 s and able to light an LED even under bended state. Such excellent performance is at least comparable to the best reports in the literature for two-electrode configuration under aqueous systems. PMID:26515442

  10. A new one-dimensional simple energy balance and carbon cycle coupled model for global warming simulation

    Science.gov (United States)

    Murakami, Kazutaka; Sasai, Takahiro; Yamaguchi, Yasushi

    2010-08-01

    Global warming and accompanying climate change may be caused by an increase in atmospheric greenhouse gasses generated by anthropogenic activities. In order to supply such a mechanism of global warming with a quantitative underpinning, we need to understand the multifaceted roles of the Earth's energy balance and material cycles. In this study, we propose a new one-dimensional simple Earth system model. The model consists of carbon and energy balance submodels with a north-south zonal structure. The two submodels are coupled by interactive feedback processes such as CO2 fertilization of net primary production (NPP) and temperature dependencies of NPP, soil respiration, and ocean surface chemistry. The most important characteristics of the model are not only that the model requires a relatively short calculation time for carbon and energy simulation compared with a General Circulation Model (GCM) and an Earth system Model of Intermediate Complexity (EMIC), but also that the model can simulate average latitudinal variations. In order to analyze the response of the Earth system due to increasing greenhouse gasses, several simulations were conducted in one dimension from the years 1750 to 2000. Evaluating terrestrial and oceanic carbon uptake output of the model in the meridional direction through comparison with observations and satellite data, we analyzed the time variation patterns of air temperature in low- and middle-latitude belts. The model successfully reproduced the temporal variation in each latitude belt and the latitudinal distribution pattern of carbon uptake. Therefore, this model could more accurately demonstrate a difference in the latitudinal response of air temperature than existing models. As a result of the model evaluations, we concluded that this new one-dimensional simple Earth system model is a good tool for conducting global warming simulations. From future projections using various emission scenarios, we showed that the spatial distribution of

  11. Contribution of root to soil respiration and carbon balance in disturbed and undisturbed grassland communities, northeast China

    Indian Academy of Sciences (India)

    Wei Wang; Jixun Guo; Takehisa Oikawa

    2007-03-01

    Changes in the composition of plant species induced by grassland degradation may alter soil respiration rates and decrease carbon sequestration; however, few studies in this area have been conducted. We used net primary productivity (NPP), microbial biomass carbon (MBC), and soil organic carbon (SOC) to examine the changes in soil respiration and carbon balance in two Chinese temperate grassland communities dominated by Leymus chinensis (undisturbed community; Community 1) and Puccinellia tenuiflora (degraded community; Community 2), respectively. Soil respiration varied from 2.5 to 11.9 g CO2 m-2 d-1 and from 1.5 to 9.3 g CO2 m-2 d-1, and the contribution of root respiration to total soil respiration from 38% to 76% and from 25% to 72% in Communities 1 and 2, respectively. During the growing season (May–September), soil respiration, shoot biomass, live root biomass, MBC and SOC in Community 2 decreased by 28%, 39%, 45%, 55% and 29%, respectively, compared to those in Community 1. The considerably lower net ecosystem productivity in Community 2 than in Community 1 (104.56 vs. 224.73 g C m-2 yr-1) suggests that the degradation has significantly decreased carbon sequestration of the ecosystems.

  12. Soils apart from equilibrium – consequences for soil carbon balance modelling

    Directory of Open Access Journals (Sweden)

    T. Wutzler

    2006-10-01

    Full Text Available Many projections of the soil carbon sink or source are based on kinetically defined carbon pool models. Parameters of these models are often determined in a way that the steady state of the model matches observed carbon stocks. The underlying simplifying assumption is that observed carbon stocks are near equilibrium. This assumption is challenged by observations of very old soils that do still accumulate carbon. In this modelling study we explored the consequences of the case where soils are apart from equilibrium. Calculation of equilibrium states of soils that are currently accumulating small amounts of carbon were performed using the Yasso model. It was found that already very small current accumulation rates cause big changes in theoretical equilibrium stocks, which can virtually approach infinity. We conclude that soils that have been disturbed several centuries ago are not in equilibrium but in a transient state because of the slowly ongoing accumulation of the slowest pool. A first consequence is that model calibrations to current carbon stocks that assume equilibrium state, overestimate the decay rate of the slowest pool. A second consequence is that spin-up runs (simulations until equilibrium overestimate stocks of recently disturbed sites. In order to account for these consequences, we propose a transient correction. This correction prescribes a lower decay rate of the slowest pool and accounts for disturbances in the past by decreasing the spin-up-run predicted stocks to match an independent estimate of current soil carbon stocks. Application of this transient correction at a Central European beech forest site with a typical disturbance history resulted in an additional carbon fixation of 5.7±1.5 tC/ha within 100 years. Carbon storage capacity of forest soils is potentially much higher than currently assumed. Simulations that do not adequately account for the transient state of soil carbon stocks neglect a substantial amount of

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

    Science.gov (United States)

    Czerny, J.; Schulz, K. G.; Boxhammer, T.; Bellerby, R. G. J.; Büdenbender, J.; Engel, A.; Krug, S. A.; Ludwig, A.; Nachtigall, K.; Nondal, G.; Niehoff, B.; Silyakova, A.; Riebesell, U.

    2013-05-01

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

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

    Directory of Open Access Journals (Sweden)

    J. Czerny

    2013-05-01

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

  15. More than just CO2: The carbon balance of a temperate mountain grassland

    Science.gov (United States)

    Wohlfahrt, G.; Hörtnagl, L.; Bamberger, I.; Hammerle, A.; Hansel, A.

    2012-12-01

    Carbon exchanged through the boundaries of an ecosystem takes on multiple forms and involves many different exchange pathways. However, most often only the fluxes of carbon dioxide (CO2) are quantified, as this compound is thought to present the major carbon flux. Here we present results from a temperate mountain grassland in Austria where fluxes of CO2, methane (CH4), of several volatile organic compounds (VOC) and of particulate carbon (harvested grass and organic fertilizer) have been quantified year-round, in some cases since over a decade, and we discuss the magnitude of and controls on these carbon fluxes. Our major findings are that CO2 fluxes represented the largest gaseous carbon fluxes, while CH4 and VOC constituted a minor fraction of carbon fluxes and matter more from the point of view of their importance for atmospheric chemistry. Among the VOCs, oxygenated compounds, such as methanol, acetaldehyde and acetone, were quantitatively most important. Management, in particular the regular harvesting of grass, represented a major disturbance to CO2 and VOC exchange, causing large emissions of carbon into the atmosphere. Particulate carbon imports and exports were of approximately equal magnitude.

  16. 西藏高原地区陆地生态系统碳素循环平衡模拟%Simulation of terrestrial carbon cycle balance model in Tibet

    Institute of Scientific and Technical Information of China (English)

    王建林; 胡单; 孙自保

    2003-01-01

    Based on climate material, the simplified terrestrial carbon cycle balance (TCCB) modelwas established, which is semi-mechanism and semi-statistics. Through TCCB model, our estimateindicates that the southeastern part of the Tibetan Plateau has much higher carbon content, and wehave calculated the litter carbon pool, NPP, carbon fluxes and described their spatial characteristicsin this region. Based on the TCCB model simulation, NPP in Tibet is 1.73 × 108 tC/a, soil organicinput rate is 0.66 × 108 tC/a, litter mineralization rate is 1.07 × 108 tC/a, vegetation litterfall rate is1.73 × 108 tC/a, the litter carbon pool is 7.26 × l08 tC, and soil decomposition rate is 309.54 × 108tC/a. The carbon budget was also analyzed based on the estimates of carbon pool and fluxes. Thespatial distributions of carbon pools and carbon fluxes in different compartments of terrestrialecosystem were depicted with map respectively in Tibet. The distribution of NPP, vegetation litterfallrate, litter, litter mineralization rate, soil organic input rate and the soil decomposition rate wereabstracted with temperature, precipitation, fractional vegetation and land feature.

  17. Assessing wildlife benefits and carbon storage from restored and natural coastal marshes in the Nisqually River Delta: Determining marsh net ecosystem carbon balance

    Science.gov (United States)

    Anderson, Frank; Bergamaschi, Brian; Windham-Myers, Lisamarie; Woo, Isa; De La Cruz, Susan; Drexler, Judith; Byrd, Kristin; Thorne, Karen M.

    2016-06-24

    Working in partnership since 1996, the U.S. Fish and Wildlife Service and the Nisqually Indian Tribe have restored 902 acres of tidally influenced coastal marsh in the Nisqually River Delta (NRD), making it the largest estuary-restoration project in the Pacific Northwest to date. Marsh restoration increases the capacity of the estuary to support a diversity of wildlife species. Restoration also increases carbon (C) production of marsh plant communities that support food webs for wildlife and can help mitigate climate change through long-term C storage in marsh soils.In 2015, an interdisciplinary team of U.S. Geological Survey (USGS) researchers began to study the benefits of carbon for wetland wildlife and storage in the NRD. Our primary goals are (1) to identify the relative importance of the different carbon sources that support juvenile chinook (Oncorhynchus tshawytscha) food webs and contribute to current and historic peat formation, (2) to determine the net ecosystem carbon balance (NECB) in a reference marsh and a restoration marsh site, and (3) to model the sustainability of the reference and restoration marshes under projected sea-level rise conditions along with historical vegetation change. In this fact sheet, we focus on the main C sources and exchanges to determine NECB, including carbon dioxide (CO2) uptake through plant photosynthesis, the loss of CO2 through plant and soil respiration, emissions of methane (CH4), and the lateral movement or leaching loss of C in tidal waters.

  18. Net ecosystem exchange of CO2 and carbon balance for eight temperate organic soils under agricultural management

    DEFF Research Database (Denmark)

    Elsgaard, Lars; Görres, C.-M.; Hoffmann, Carl Christian

    2012-01-01

    This study presents the first annual estimates of net ecosystem exchange (NEE) of CO2 and net ecosystem carbon balances (NECB) of contrasting Danish agricultural peatlands. Studies were done at eight sites representing permanent grasslands (PG) and rotational (RT) arable soils cropped to barley......, potato or forage grasses in three geo-regional settings. Using an advanced flux-chamber technique, NEE was derived from modelling of ecosystem respiration (ER) and gross primary production (GPP) with temperature and photosynthetically active radiation as driving variables. At PG (n = 3) and RT (n = 5...

  19. FROM ZERO-DIMENSIONAL TO 2-DIMENSIONAL CARBON NANOMATERIALS - part II: GRAPHENE

    Directory of Open Access Journals (Sweden)

    Cătălin IANCU

    2012-05-01

    Full Text Available As was presented in the first part of this review paper, lately, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nanotechnology which is called carbon-related nanomaterials. In this review paper are presented some of the most exciting and important developments in the synthesis, properties, and applications of low-dimensional carbon nanomaterials. In this part of the paper are presented the synthesis techniques used to produce the two-dimensional carbon nanomaterials (including graphene, and also the most important properties and potential applications of graphene.

  20. The carbon balance of forest soils: detectability of changes in soil carbon stocks in temperate and Boreal forests.

    Science.gov (United States)

    Conen, Frauz; Zerva, Argyro; Arrouays, Dominique; Jolivet, Claude; Jarvis, Paul G; Grace, John; Mencuccini, Maurizio

    2005-01-01

    Estimating soil carbon content as the product of mean carbon concentration and bulk density can result in considerable overestimation. Carbon concentration and soil mass need to be measured on the same sample and carbon contents calculated for each individual sample before averaging. The effect of this bias is likely to be smaller (but still greater than zero) when the primary objective is to determine stock changes over time. Variance and mean carbon content are significantly and positively related to each other, although some sites showed much higher variability than predicted by this relationship, as a likely consequence of their particular site history, forest management, and micro-topography. Because of the proportionality between mean and variance, the number of samples required to detect a fixed change in soil carbon stocks varied directly with the site mean carbon content from less than 10 to several thousands across the range of carbon stocks normally encountered in temperate and Boreal forests. This raises important questions about how to derive an optimal sampling strategy across such a varied range of conditions so as to achieve the aims of the Kyoto Protocol. Overall, on carbon-poor forest sites with little or no disturbance to the soil profile, it is possible to detect changes in total soil organic carbon over time of the order of 0.5 kg (C) m(-2) with manageable sample sizes even using simple random sampling (i.e., about 50 samples per sampling point). More efficient strategies will reveal even smaller differences. On disturbed forest sites (ploughed, windthrow) this is no longer possible (required sample sizes are much larger than 100). Soils developed on coarse aeolian sediments (sand dunes), or where buried logs or harvest residues of the previous rotation are present, can also exhibit large spatial variability in soil carbon. Generally, carbon-rich soils will always require larger numbers of samples. On these sites, simple random sampling is

  1. Development of a Method for Measuring Carbon Balance in Chemical Sequestration of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Zhongxian; Pan, Wei-Ping; Riley, John T.

    2006-09-09

    Anthropogenic CO2 released from fossil fuel combustion is a primary greenhouse gas which contributes to “global warming.” It is estimated that stationary power generation contributes over one-third of total CO2 emissions. Reducing CO2 in the atmosphere can be accomplished either by decreasing the rate at which CO2 is emitted into the atmosphere or by increasing the rate at which it is removed from it. Extensive research has been conducted on determining a fast and inexpensive method to sequester carbon dioxide. These methods can be classified into two categories, CO2 fixation by natural sink process for CO2, or direct CO2 sequestration by artificial processes. In direct sequestration, CO2 produced from sources such as coal-fired power plants, would be captured from the exhausted gases. CO2 from a combustion exhaust gas is absorbed with an aqueous ammonia solution through scrubbing. The captured CO2 is then used to synthesize ammonium bicarbonate (ABC or NH4HCO3), an economical source of nitrogen fertilizer. In this work, we studied the carbon distribution after fertilizer is synthesized from CO2. The synthesized fertilizer in laboratory is used as a “CO2 carrier” to “transport” CO2 from the atmosphere to crops. After biological assimilation and metabolism in crops treated with ABC, a considerable amount of the carbon source is absorbed by the plants with increased biomass production. The majority of the unused carbon source percolates into the soil as carbonates, such as calcium carbonate (CaCO3) and magnesium carbonate (MgCO3). These carbonates are environmentally benign. As insoluble salts, they are found in normal rocks and can be stored safely and permanently in soil. This investigation mainly focuses on the carbon distribution after the synthesized fertilizer is applied to soil. Quantitative examination of carbon distribution in an ecosystem is a challenging task since the carbon in the soil may come from various sources. Therefore synthesized 14C

  2. Carbon dioxide stripping in aquaculture -- part III: model verification

    Science.gov (United States)

    Colt, John; Watten, Barnaby; Pfeiffer, Tim

    2012-01-01

    Based on conventional mass transfer models developed for oxygen, the use of the non-linear ASCE method, 2-point method, and one parameter linear-regression method were evaluated for carbon dioxide stripping data. For values of KLaCO2 < approximately 1.5/h, the 2-point or ASCE method are a good fit to experimental data, but the fit breaks down at higher values of KLaCO2. How to correct KLaCO2 for gas phase enrichment remains to be determined. The one-parameter linear regression model was used to vary the C*CO2 over the test, but it did not result in a better fit to the experimental data when compared to the ASCE or fixed C*CO2 assumptions.

  3. Interactions between nitrogen deposition, land cover conversion, and climate change determine the contemporary carbon balance of Europe

    Directory of Open Access Journals (Sweden)

    G. Churkina

    2010-09-01

    land use changes are needed to further improve the quantitative understanding of the driving forces of the European land carbon balance.

  4. Mass and energy balance of the carbonization of babassu nutshell as affected by temperature

    Directory of Open Access Journals (Sweden)

    Thiago de Paula Protásio

    2014-03-01

    Full Text Available The objective of this work was to evaluate the carbonization yield of babassu nutshell as affected by final temperature, as well as the energy losses involved in the process. Three layers constituting the babassu nut, that is, the epicarp, mesocarp and endocarp, were used together. The material was carbonized, considering the following final temperatures: 450, 550, 650, 750, and 850ºC. The following were evaluated: energy and charcoal yields, pyroligneous liquid, non-condensable gases, and fixed carbon. The use of babassu nutshell can be highly feasible for charcoal production. The yield of charcoal from babassu nutshell carbonization was higher than that reported in the literature for Eucalyptus wood carbonization, considering the final temperature of 450ºC. Charcoal and energy yields decreased more sharply at lower temperatures, with a tendency to stabilize at higher temperatures. The energy yields obtained can be considered satisfactory, with losses between 45 and 52% (based on higher heating value and between 43 and 49% (based on lower heating value at temperatures ranging from 450 to 850ºC, respectively. Yields in fixed carbon and pyroligneous liquid are not affected by the final carbonization temperature.

  5. Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

    Directory of Open Access Journals (Sweden)

    J. Järveoja

    2015-10-01

    Full Text Available Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C and greenhouse gas (GHG exchanges is still limited. The aim of this study was to investigate the impact of contrasting water table levels (WTL on the annual C and GHG balances of restoration treatments with high (Res-H and low (Res-L WTL relative to an unrestored bare peat (BP site. Measurements of carbon dioxide (CO2, methane (CH4 and nitrous oxide (N2O fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in Res-H relative to Res-L. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in Res-L compared to Res-H. However, the means of the measured net ecosystem CO2 exchanges (NEE were not significantly different between Res-H and Res-L. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges in Res-H and Res-L, respectively. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, Res-H, Res-L and BP were C sources of 111, 103 and 268 g C m−2 yr−1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha−1 yr−1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments three years following restoration. However, the C and GHG balances in Res-H and Res-L were considerably lower than in BP owing to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative

  6. Impact of water table level on annual carbon and greenhouse gas balances of a restored peat extraction area

    Science.gov (United States)

    Järveoja, Järvi; Peichl, Matthias; Maddison, Martin; Soosaar, Kaido; Vellak, Kai; Karofeld, Edgar; Teemusk, Alar; Mander, Ülo

    2016-05-01

    Peatland restoration may provide a potential after-use option to mitigate the negative climate impact of abandoned peat extraction areas; currently, however, knowledge about restoration effects on the annual balances of carbon (C) and greenhouse gas (GHG) exchanges is still limited. The aim of this study was to investigate the impact of contrasting mean water table levels (WTLs) on the annual C and GHG balances of restoration treatments with high (ResH) and low (ResL) WTL relative to an unrestored bare peat (BP) site. Measurements of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were conducted over a full year using the closed chamber method and complemented by measurements of abiotic controls and vegetation cover. Three years following restoration, the difference in the mean WTL resulted in higher bryophyte and lower vascular plant cover in ResH relative to ResL. Consequently, greater gross primary production and autotrophic respiration associated with greater vascular plant cover were observed in ResL compared to ResH. However, the means of the measured net ecosystem CO2 exchanges (NEE) were not significantly different between ResH and ResL. Similarly, no significant differences were observed in the respective means of CH4 and N2O exchanges. In comparison to the two restored sites, greater net CO2, similar CH4 and greater N2O emissions occurred in BP. On the annual scale, ResH, ResL and BP were C sources of 111, 103 and 268 g C m-2 yr-1 and had positive GHG balances of 4.1, 3.8 and 10.2 t CO2 eq ha-1 yr-1, respectively. Thus, the different WTLs had a limited impact on the C and GHG balances in the two restored treatments 3 years following restoration. However, the C and GHG balances in ResH and ResL were considerably lower than in BP due to the large reduction in CO2 emissions. This study therefore suggests that restoration may serve as an effective method to mitigate the negative climate impacts of abandoned peat extraction areas.

  7. Reconstruction of annual carbon dynamics and balance for an oligotrophic pine fen

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J.; Silvola, J.; Aaltonen, H. [Joensuu Univ. (Finland). Dept. of Biology; Talanov, A.; Ikkonen, E. [Karelian Research Centre of Russian Academy of Sciences (Russian Federation). Inst. of Biology; Nykaenen, H.; Martikainen, P.J. [National Public Health Inst. Kuopio (Finland). Dept. of Environmental Microbiology

    1996-12-31

    Atmospheric carbon dioxide (CO{sub 2}) is bound by mire vegetation in photosynthesis during the growing season, and is re-released by respiration of plants, soil animals and microorganisms consuming dead organic matter. A small proportion of annual primary production may fall below the water table to anoxic conditions and thus escapes the oxidative decomposition. Also from anoxic peat, carbon is released with clear seasonal and spatial variation as methane (CH{sub 4}.). The rate of carbon accumulation in peat depends on the annual inbalance of plant production and litter decomposition. Exchange of CO{sub 2} and CH{sub 4} between peat, vegetation and the atmosphere thus reflects the dynamics of carbon flows in the ecosystem. Net ecosystem CO{sub 2} exchange (PN), total CO{sub 2} release (RTOT) and CH{sub 4} release (D) from different treeless surfaces of low-sedge Sphagnum papillosum pine fen was studied in eastern Finland. (8 refs.)

  8. Evolution of Sustainable Carbon Cycling Processes in China

    Institute of Scientific and Technical Information of China (English)

    Zhuang Yahui; Zhang Hongxun; Wang Xiaoke; Fang Jinyun

    2004-01-01

    This report summarizes the surveys on carbon inventories and initiatives on sustainable carbon cycling taken by RCEES. The first part of this report deals with the concept of sustainable carbon cycling, the historical evolution of carbon cycling processes in China, carbon pool enhancement, value addition, carbon sequestration and carbon balance.The second part covers the modeling of carbon dynamics, emission inventories of various carboncontaining greenhouse gases and their potential abatement measures.

  9. Carbon balance at represenative agroecosystems of Central European Russia with different crops assessed by eddy covariance method

    Science.gov (United States)

    Yaroslavtsev, Alexis; Meshalkina, Joulia; Mazirov, Ilya

    2016-04-01

    Despite the fact that in Russia cropland's soils carbon loses 9 time higher than forest's soils ones (Stolbovoi, 2002), agroecosystems were not given sufficient attention and most of the papers are devoted to forestry and natural ecosystems. Carbon balance was calculated at the Precision Farming Experimental Fields of the Russian Timiryazev State Agricultural University, Moscow, Russia, for two agroecosystems with different crops from the same crop rotation studied for 2 years. The experimental site has a temperate and continental climate and situated in south taiga zone with Arable Sod-Podzoluvisols (Albeluvisols Umbric). Vertical fluxes of carbon dioxide were measured with eddy covariance technique, statistical method to measure and calculate turbulent fluxes within atmospheric boundary layers (Burba, 2013). Crop rotation included potato, winter wheat, barley and vetch and oat mix. Two fields of the same crop rotation were studied in 2013-2014. One of the fields (A) was used in 2013 for barley planting (Hordeum vulgare L.). The field B was in 2013 used for planting together vetch (Vicia sativa L.) and oats (Avena sativa L.). Inversely oats and vetch grass mixt was sown in 2014 on field A. Winter wheat was sown on field A in the very beginning of September. On the second field (B) in 2014 winter wheat occurred from under the snow in the phase of tillering, after harvesting it in mid of July, white mustard (Sinapis alba) was sown for green manure. Carbon uptake (NEE negative values) was registered only for the field with winter wheat and white mustard; perhaps because the two crops were cultivated on the field within one growing season. Three other cases showed CO2 emission. Great difference in 82 g C m-2 per year in NEE between two fields with vetch and oat mix was related to higher difference in grass yields. NEE for barley field was positive during the whole year; considering only the growing season, NEE for barley was 100 g C m-2 lower and was negative. Closed

  10. Benthic biogeochemical cycling, nutrient stoichiometry, and carbon and nitrogen mass balances in a eutrophic freshwater bay

    Science.gov (United States)

    Klump, J.V.; Fitzgerald, S.A.; Waplesa, J.T.

    2009-01-01

    Green Bay, while representing only ,7% of the surface area and ??1.4% of the volume of Lake Michigan, contains one-third of the watershed of the lake, and receives approximately one-third of the total nutrient loading to the Lake Michigan basin, largely from the Fox River at the southern end of the bay. With a history of eutrophic conditions dating back nearly a century, the southern portion of the bay behaves as an efficient nutrient and sediment trap, sequestering much of the annual carbon and nitrogen input within sediments accumulating at up to 1 cm per year. Depositional fluxes of organic matter varied from ??0.1 mol C m-2 yr-1 to >10 mol C m-2 yr-1 and were both fairly uniform in stoichiometric composition and relatively labile. Estimates of benthic recycling derived from pore-water concentration gradients, whole-sediment incubation experiments, and deposition-burial models of early diagenesis yielded an estimated 40% of the carbon and 50% of the nitrogen recycled back into the overlying water. Remineralization was relatively rapid with ??50% of the carbon remineralized within <15 yr of deposition, and a mean residence time for metabolizable carbon and nitrogen in the sediments of 20 yr. On average, organic carbon regeneration occurred as 75% CO2, 15% CH4, and 10% dissolved organic carbon (DOC). Carbon and nitrogen budgets for the southern bay were based upon direct measurements of inputs and burial and upon estimates of export and production derived stoichiometrically from a coupled phosphorus budget. Loadings of organic carbon from rivers were ??3.7 mol m-2 yr-1, 80% in the form of DOC and 20% as particulate organic carbon. These inputs were lost through export to northern Green Bay and Lake Michigan (39%), through sediment burial (26%), and net CO2 release to the atmosphere (35%). Total carbon input, including new production, was 4.54 mol m-2 C yr-1, equivalent to ??10% of the gross annual primary production. Nitrogen budget terms were less well quantified

  11. Carbon stocks, greenhouse gas emissions and water balance of Sudanese savannah woodlands in relation to climate change

    Energy Technology Data Exchange (ETDEWEB)

    Alam, S. A.

    2013-06-01

    Understanding the carbon (C) sequestration potential of drylands requires knowledge of the stocks of C in soils and biomass and on the factors affecting them. The overall aim of the study was to determine and evaluate the variation in the C stocks and water balance of Acacia savannah woodlands across the dryland (arid and semi-arid) region (10-16 deg N; 21-36 deg E) of the former Sudan (now mainly in the Republic of the Sudan) and how they are related to climatic factors and may be affected by climate change. The role played by small but numerous brick making industries on woodland deforestation in the region and greenhouse gas production was also investigated. The study region is often referred to as the gum belt because it is the world's major source of gum Arabic, which is harvested from Acacia trees. The soils in the centre and west of the region are mainly Arenosols (sandy soils) and those in the eastern part are mainly Vertisols (clay soils). The soils are C poor and often in a degraded state. This dissertation consists of a summary section and four articles (Study I, II, III and IV). Study I focuses on fuelwood consumption by the brick making industries (BMIs) and associated deforestation and greenhouse gas (GHG) emissions. In Study II the C densities (g C m-2) of the woodland tree biomass and soil (1 m) for 39 map sheets covering the study region were determined from national forest inventory data and global soil databases and the dependence on mean annual precipitation (MAP) and mean annual temperature (MAT) determined. The water balance of savannah woodlands for the same 39 map sheets was modelled in Study III and the variation in water balance components across the region evaluated. The potential impacts of climate change on woodland biomass C density and water-use (actual evapotranspiration, AET) was analysed for eight of the map sheets in Study IV. Sudanese BMIs consume a considerable amount of fuelwood that mainly comes from unsustainably managed

  12. Balancing the carbon market. Analysing the international carbon market and abatement costs in 2020 for low-concentration targets

    Energy Technology Data Exchange (ETDEWEB)

    Den Elzen, M.G.J.; Mendoza-Beltran, M.A.; Piris-Cabezas, P.; Van Vuuren, D.P.

    2009-08-15

    This report describes our analysis of the impact of various policy choices and scientific uncertainties on the price of tradable emission units on the global carbon market in 2020 and the associated abatement costs. Our analysis was done under the assumption that the overall goal is to stabilise long-term greenhouse gas concentrations at 450 ppm CO2-eq. To meet these stabilisation targets on the long-term, Annex I countries as a group need to reduce by 25-40% below 1990 levels by 2020, and non-Annex I countries as a group need to keep emissions substantially below baseline (about 15 to 30%). The integrated modelling framework FAIR 2.2 is used for our analysis. The main findings of this study are: the degree of ambition for reductions of Annex I and non-Annex I countries is the most important policy choice influencing the price and abatement costs. Other less important policy choices include the ambition of US climate policy and the participation of the developing countries in the global carbon market. By allowing the use of forest-based options - including avoiding deforestation - for compliance in a well-designed carbon trading system, the global abatement costs could be reduced by between 25% and 65%. This would also make ambitious mitigation targets more feasible. In addition to the policy choices, important scientific uncertainties, in particular the baseline emissions (i.e. emissions in the absence of climate policy) and the assumed marginal abatement costs, strongly influence the carbon market.

  13. Present and Future Carbon Balance of Russia's Northern Ecosystems. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chapin, F. Stuart III; Zimov, Sergei A.

    2000-08-28

    Recent increases in the seasonal amplitude of atmospheric CO{sub 2} at high latitudes suggest a widespread biospheric response to high-latitude warming. We have shown that the seasonal amplitude of net ecosystem carbon exchange by northern Siberian ecosystems is greater in disturbed than undisturbed sites, due to increased summer influx and increased winter efflux. Net carbon gain in summer and respiration in winter were greater in a cool than in a warm year, especially in disturbed sites and did not differ between high-arctic and treeline sites, suggesting that high-latitude warming, if it occurred, would have little effect or would reduce seasonal amplitude of carbon exchange. We suggest that increased disturbance contributes significantly to the amplified seasonal cycle of atmospheric CO{sub 2} at high latitudes.

  14. Modelling the carbon and nitrogen balances of direct land use changes from energy crops in Denmark

    DEFF Research Database (Denmark)

    Hamelin, Lorie; Jørgensen, Uffe; Petersen, Bjørn Molt;

    2012-01-01

    This paper addresses the conversion of Danish agricultural land from food/feed crops to energy crops. To this end, a life cycle inventory, which relates the input and output flows from and to the environment of 528 different crop systems, is built and described. This includes seven crops (annuals......- and micronutrients are presented. The inventory results highlight Miscanthus as a promising energy crop, indicating it presents the lowest emissions of nitrogen compounds, the highest amount of carbon dioxide sequestrated from the atmosphere, a relatively high carbon turnover efficiency and allows to increase soil...... organic carbon. Results also show that the magnitude of these benefits depends on the harvest season, soil types and climatic conditions. Inventory results further highlight winter wheat as the only annual crop where straw removal for bioenergy may be sustainable, being the only annual crop not involving...

  15. Instrumentation and analytical methods in carbon balance studies - inorganic components in a marine environment

    Energy Technology Data Exchange (ETDEWEB)

    Skjelvan, I.; Johannessen, T.; Miller, L.; Stoll, M.

    1996-03-01

    This paper was read at the workshop ``The Norwegian Climate and Ozone Research Programme`` held on 11-12 March 1996. Substantial amounts of anthropogenic CO{sub 2} enters the atmosphere. The land biota acts as a sink for CO{sub 2}, with uncertain consequences. About 30% of the anthropogenic CO{sub 2} added to the atmosphere is absorbed by the ocean and how the ocean acts as a sink is central in understanding the carbon cycle. In their project the authors investigate the inorganic carbon in the ocean, especially total dissolved inorganic carbon, alkalinity, and partial pressure of CO{sub 2} (pCO{sub 2}) in surface ocean and atmosphere. To determine total dissolved inorganic carbon, coulometric analysis is used in which an exact amount of sea water is acidified and the amount of carbon extracted is determined by a coulometer. Alkalinity is determined by potentiometric titration. In the pCO{sub 2} measurement, a small amount of air is circulated in a large amount of sea water and when after some time the amount of CO{sub 2} in the air reflects the CO{sub 2} concentration in the water, the pCO{sub 2} in the gas phase is determined by infra-red detection. The atmospheric pCO{sub 2} is also determined, and the difference between the two partial pressures gives information about source or sink activities. Total carbon and alkalinity measurements are done on discrete samples taken from all depths in the ocean, but for partial pressure detection an underway system is used, which determines the pCO{sub 2} in the surface ocean continuously

  16. 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.

  17. Contribution of chloroplast biogenesis to carbon-nitrogen balance during early leaf development in rice.

    Science.gov (United States)

    Kusumi, Kensuke; Hirotsuka, Shoko; Shimada, Hiroshi; Chono, Yoko; Matsuda, Osamu; Iba, Koh

    2010-07-01

    Chloroplast biogenesis is most significant during the changes in cellular organization associated with leaf development in higher plants. To examine the physiological relationship between developing chloroplasts and host leaf cells during early leaf development, we investigated changes in the carbon and nitrogen contents in leaves at the P4 developmental stage of rice, during which leaf blade structure is established and early events of chloroplast differentiation occur. During the P4 stage, carbon content on a dry mass basis remained constant, whereas the nitrogen content decreased by 30%. Among carbohydrates, sucrose and starch accumulated to high levels early in the P4 stage, and glucose, fructose and cellulose degradation increased during the mid-to-late P4 stage. In the chloroplast-deficient leaves of the virescent-1 mutant of rice, however, the carbon and nitrogen contents, as well as the C/N ratio during the P4 stage, were largely unaffected. These observations suggest that developing rice leaves function as sink organs at the P4 stage, and that chloroplast biogenesis and carbon and nitrogen metabolism in the leaf cell is regulated independently at this stage.

  18. The impact of different management techniques on carbon balance of a pine stand after windthrow

    Science.gov (United States)

    Ziemblinska, Klaudia; Urbaniak, Marek; Merbold, Lutz; Chojnicki, Bogdan H.; Olejnik, Janusz

    2015-04-01

    Forest ecosystems cover approximately 1/3 of the global land area (and 29.8% in Poland). Since forests are constantly exposed to various types of disturbances - both natural and anthropogenic such as fires, wind, insects outbreaks or clear cuts - it is important to investigate the impact of such damages on the carbon dynamics. This becomes even more important due to the fact that future climate change will most likely result in a higher frequency and intensity of extreme climatic events. Even though wind damages cause large disturbances to forests only few places in the world exist where continuous measurements of carbon exchange (CO2) in windthrown sites are carried out. Besides the opportunity to assess the carbon dynamics following wind disturbance, there is an additional possibility of evaluating differences in post windthrow forest management practices. To fill this knowledge gap we set up two measuring stations in north-western Poland in the 500ha area of pine forest damaged by tornado in July 2012, to assess the impact of such disturbance on CO2 and H2O exchange by use of Eddy Covariance (EC) technique (Tlen I and Tlen II). Both sites are characterized by similar climatic as well as soil conditions and are located 3km from each other. While at the site Tlen I all biomass (coarse and fine woody debris were collected together with stumps) was removed and ploughed thereafter, at Tlen II only trunks and main branches were taken out from the site without ploughing. Total harvested biomass per hectare, as derived from local forest inventory, were almost 18 % higher at Tlen I than Tlen II site (where uprooted stumps were left to decompose). First analysis of the eddy covariance data shows that both sites are significant carbon sources. Emissions of carbon dioxide from the non-ploughed site (Tlen II) are higher than from the ploughed site (Tlen I). Both sites released more than 8.1 t of CO2 per ha during a three month time period (mid July to mid August 2014) after

  19. Climatic Benefit of Swiss Forest Cover Change: Including Albedo Change into Net Carbon Balance

    Science.gov (United States)

    Schwaab, J.; Lehning, M.; Bebi, P.

    2012-12-01

    Forests influence climate through physical, chemical and biological processes. It has been shown that warming caused by the comparatively low albedo of forests (albedo-effect), can reduce or even exceed cooling caused by carbon storage in forests (CO2-effect). Although warming caused by albedo and the amount of carbon storage depend on local characteristics, studies are lacking that investigate the combined local patterns of albedo and CO2-effect. Our study area, Switzerland, provides a variety of geographical features and thus the possibility to show how different geographical variables influence the two effects. We used the concept of radiative forcing to compare the effect of a changing albedo and a change in atmospheric CO2 concentration due to land cover change in the past. The change of forest cover was analysed over a period of 12 years based on aerial photographs. We estimate the albedo-effect by combining albedo data derived from the satellite sensor MODIS and data on snow cover derived from the satellite sensor AVHRR. Changes in carbon storage were calculated as differences in biomass and soil stocks of specific land cover classes. We found carbon storage induced cooling to be higher than albedo induced warming everywhere in Switzerland. However, especially in altitudes over 1200 m the albedo-effect reduced the benefits of carbon storage by more than 50%. In lower altitudes the albedo change was less important. The albedo-effect in altitudes above 1200 m was more relevant because of a more persistent snow-cover, a slightly higher global radiation and less additional carbon storage. The relevance of warming caused by an albedo change did not only depend on altitude, but also on the characteristics of forest cover change. While transitions from open land to open forest were accompanied by high albedo changes, the albedo change was only marginal if open forest turned into closed forest. Since snow cover has a large influence on the albedo effect, we included

  20. Carbon balance of China constrained by CONTRAIL aircraft CO2 measurements

    Directory of Open Access Journals (Sweden)

    F. Jiang

    2014-03-01

    Full Text Available Terrestrial 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 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. 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 have improved the inversion results.

  1. CO{sub 2} and CH{sub 4} fluxes and carbon balance in the atmospheric interaction of boreal peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Alm, J.

    1997-12-31

    Release of CO{sub 2} from peat was studied using IR analyzer in a range of boreal peatlands under varying nutrient status and moisture conditions. Root associated CO{sub 2} efflux was separated from the total release by experiments both in the field and in a greenhouse. Emissions of CO{sub 2} and CH{sub 4} (the latter by gas chromatography) were measured during the snow-covered period and their contribution to the annual fluxes of these gases was inspected. Ecosystem exchange of CO{sub 2} under varying irradiation, temperature and moisture conditions was measured at different microsites at two peatland sites with different nutrient ecology. One site represented minerotrophic conditions during a wet growing season and the other site ombrotrophic conditions during an exceptionally dry growing season. Annual carbon balances were compiled for the two sites, and the role of the microsites in the annual carbon balance and CH{sub 4} release was studied. The Holocene history of CO{sub 2} sequestration and CH{sub 4} emission dynamics in a raised mire were simulated using lateral and vertical growth rates derived from radiocarbon ages of peat samples from mire bottom and vertical cores. The model was formulated for a geographic information system (GIS). Artificial or natural lowering of water table increased CO{sub 2} release from peat. A drought lasting from late May to July caused a 90 g C m{sup 2} net loss in the annual C balance of a natural ombrotrophic bog. In drained forested sites the increase in peat CO{sub 2} release could be even 100 %, but the development of the tree layer at least partially compensated for these losses. Wet conditions induced a net accumulation of 67 g C m{sup -2}a{sup -1} in the minerotrophic fen site, while the long term average accumulation rate is estimated to be only 15 g C m{sup -2}a{sup -1} for Finnish fens. Carbon balance in boreal peatlands is thus extremely sensitive to year-to-year climatic variations. Root activity of vascular plants

  2. A non-oscillatory balanced scheme for an idealized tropical climate model. Part II. Nonlinear coupling and moisture effects

    Energy Technology Data Exchange (ETDEWEB)

    Khouider, Boualem [University of Victoria, Mathematics and Statistics, Victoria, B.C. (Canada); Majda, Andrew J. [New York University, Department of Mathematics and Center for Atmosphere/Ocean Sciences, NY (United States); Courant Institute, New York, NY (United States)

    2005-10-01

    We use the non-oscillatory balanced numerical scheme developed in Part I to track the dynamics of a dry highly nonlinear barotropic/baroclinic coupled solitary wave, as introduced by Biello and Majda (2004), and of the moisture fronts of Frierson et al. (2004) in the presence of dry gravity waves, a barotropic trade wind, and the beta effect. It is demonstrated that, for the barotropic/baroclinic solitary wave, except for a little numerical dissipation, the scheme utilized here preserves total energy despite the strong interactions and exchange of energy between the baroclinic and barotropic components of the flow. After a short transient period where the numerical solution stays close to the asymptotic predictions, the flow develops small scale eddies and ultimately becomes highly turbulent. It is found here that the interaction of a dry gravity wave with a moisture front can either result in a reflection of a fast moistening front or the pure extinction of the precipitation. The barotropic trade wind stretches the precipitation patches and increases the lifetime of the moisture fronts which decay naturally by the effects of dissipation through precipitation while the Coriolis effect makes the moving precipitation patches disappear and appear at other times and places. (orig.)

  3. Energy and carbon balances in cheatgrass, an essay in autecology. [Shortwave radiation, radiowave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hinds, W.T.

    1975-01-01

    An experiment to determine the fates of energy and carbon in cheatgrass (Bromus tectorum L.) was carried out on steep (40/sup 0/) north- and south-facing slopes on a small earth mound, using many small lysimeters to emulate swards of cheatgrass. Meteorological conditions and energy fluxes that were measured included air and soil temperatures, relative humidity, wind speed, incoming shortwave radiation, net all-wave radiation, heat flux to the soil, and evaporation and transpiration separately. The fate of photosynthetically fixed carbon during spring growth was determined by analysis of the plant tissues into mineral nutrients, crude protein, crude fat, crude fiber, and nitrogen-free extract (NFE) for roots, shoots, and seeds separately. (auth)

  4. Bioanalytical effect-balance model to determine the bioavailability of organic contaminants in sediments affected by black and natural carbon.

    Science.gov (United States)

    Bräunig, Jennifer; Tang, Janet Y M; Warne, Michael St J; Escher, Beate I

    2016-08-01

    In sediments several binding phases dictate the fate and bioavailability of organic contaminants. Black carbon (BC) has a high sorptive capacity for organic contaminants and can limit their bioavailability, while the fraction bound to organic carbon (OC) is considered to be readily desorbable and bioavailable. We investigated the bioavailability and mixture toxicity of sediment-associated contaminants by combining different extraction techniques with in vitro bioanalytical tools. Sediments from a harbour with high fraction of BC, and sediments from remote, agricultural and urban areas with lower BC were treated with exhaustive solvent extraction, Tenax extraction and passive sampling to estimate total, bioaccessible and bioavailable fractions, respectively. The extracts were characterized with cell-based bioassays that measure dioxin-like activity (AhR-CAFLUX) and the adaptive stress response to oxidative stress (AREc32). Resulting bioanalytical equivalents, which are effect-scaled concentrations, were applied in an effect-balance model, consistent with a mass balance-partitioning model for single chemicals. Sediments containing BC had most of the bioactivity associated to the BC fraction, while the OC fraction played a role for sediments with lower BC. As effect-based sediment-water distribution ratios demonstrated, most of the bioactivity in the AhR-CAFLUX was attributable to hydrophobic chemicals while more hydrophilic chemicals activated AREc32, even though bioanalytical equivalents in the aqueous phase remained negligible. This approach can be used to understand the fate and effects of mixtures of diverse organic contaminants in sediments that would not be possible if single chemicals were targeted by chemical analysis; and make informed risk-based decisions concerning the management of contaminated sediments.

  5. Carbon Balance of No-Till Soybean with Winter Wheat Cover Crop in the Southeastern United States

    Science.gov (United States)

    Gebremedhin, M. T.; Loescher, H.; Tsegaye, T.

    2012-12-01

    The southeast is an important agricultural region in the U.S. and key component of the continental carbon budget. Croplands in the region store a substantial amount of soil organic carbon (C). However, their C sink status may be altered under the projected changes in precipitation pattern for the region. The study was conducted at Winfred Thomas Agricultural Research Station, Hazel Green, Alabama (2007-2009). We investigated the seasonal and interannual variation in net ecosystem exchange of CO2 (NEE) of winter wheat (Tricticum aestivum) and soybean (Glycine max) using the eddy covariance method. Annual C balance ranged from the highest source in 2007 (NEE = 100 g C m-2 y-1) to sink (-20 g C m-2 y-1) in 2009. Annual ecosystem respiration (Re) ranged between 750 and 1013 g C m-2 y-1, while gross ecosystem productivity (GEP) was 650-1034 g C m-2 y-1. Seasonal NEE for soybean ranged between 42 and -66 g C m-2. Stronger winter wheat NEE (-80.0, -80.4, -40.0 g C m-2 for 2007, 2008 and 2009) than soybean suggested the importance of winter C uptakes offsetting summer C losses. Re was controlled by air temperature, and it varied between 286 and 542 g C m-2 for soybean, and between 160 and 313 g C m-2 for winter wheat. Precipitation was key determinant of C balance implying larger C release during drought periods. During fallow months, the site was C source. If we include removal of grain off site, this system could become a C source under all conditions.

  6. [Soil respiration and carbon balance in wheat field under conservation tillage].

    Science.gov (United States)

    Zhang, Sai; Wang, Long-Chang; Huang, Zhao-Cun; Jia, Hui-Juan; Ran, Chun-Yan

    2014-06-01

    In order to study the characteristics of carbon sources and sinks in the winter wheat farmland ecosystem in southwest hilly region of China, the LI6400-09 respiratory chamber was adopted in the experiment conducted in the experimental field in Southwest University in Chongqing. The soil respiration and plant growth dynamics were analyzed during the growth period of wheat in the triple intercropping system of wheat-maize-soybean. Four treatments including T (traditional tillage), R (ridge tillage), TS (traditional tillage + straw mulching), and RS (ridge tillage + straw mulching) were designed. Root biomass regression (RR) and root exclusion (RE) were used to compare the contribution of root respiration to total soil respiration. The results showed that the average soil respiration rate was 1.71 micromol x (m2 x s)(-1) with a variation of 0.62-2.91 micromol x (m2 x s)(-1). Significant differences in soil respiration rate were detected among different treatments. The average soil respiration rate of T, R, TS and RS were 1.29, 1.59, 1.99 and 1.96 micromol x (m2 x s)(-1), respectively. R treatment did not increase the soil respiration rate significantly until the jointing stage. Straw mulching treatment significantly increased soil respiration, with a steadily high rate during the whole growth period. During the 169 days of growth, the total soil respiration was 2 266.82, 2799.52, 3 483.73 and 3 443.89 kg x hm(-2) while the cumulative aboveground biomasses were 51 800.84, 59 563.20, 66 015.37 and 7 1331.63 kg x hm(-2). Compared with the control, the yield of R, TS and RS increased by 14.99%, 27.44% and 37.70%, respectively. The contribution of root respiration to total soil respiration was 47.05% by RBR, while it was 53.97% by RE. In the early growth period, the carbon source was weak. The capacity of carbon sink started to increase at the jointing stage and reached the maximum during the filling stage. The carbon budget of wheat field was 5 924.512, 6743.807, 8350

  7. Carbon Balance and Contribution of Harvested Wood Products in China Based on the Production Approach of the Intergovernmental Panel on Climate Change

    Directory of Open Access Journals (Sweden)

    Chunyi Ji

    2016-11-01

    Full Text Available The carbon sequestration of harvested wood products (HWP plays an important role in climate mitigation. Accounting the carbon contribution of national HWP carbon pools has been listed as one of the key topics for negotiation in the United Nations Framework Convention on Climate Change. On the basis of the revised Production Approach of the Intergovernmental Panel on Climate Change (2013 (IPCC, this study assessed the accounting of carbon stock and emissions from the HWP pool in China and then analyzed its balance and contribution to carbon mitigation from 1960 to 2014. Research results showed that the accumulated carbon stock in China’s HWP carbon pool increased from 130 Teragrams Carbon (TgC in 1960 to 705.6 TgC in 2014. The annual increment in the carbon stock rose from 3.2 TgC in 1960 to 45.2 TgC in 2014. The category of solid wood products accounted for approximately 95% of the annual amount. The reduction in carbon emissions was approximately twelve times that of the emissions from the HWP producing and processing stage during the last decade. Furthermore, the amount of carbon stock and emission reduction increased from 23 TgC in 1960 to 76.1 TgC in 2014. The annual contribution of HWP could compensate for approximately 2.9% of the national carbon dioxide emissions in China.

  8. A Multi-Year Comparison of No-Till Versus Conventional-Till Effects on the Carbon Balance in a Corn/Soybean Agro-Ecosystem Using Eddy Covariance

    Science.gov (United States)

    Joo, E.; Slattery, R.; Meyers, T. P.; Bernacchi, C.

    2015-12-01

    Dramatic increases in atmospheric CO2 concentrations since the industrial revolution are in large part due to the release of carbon previously stored in the soil. No-till strategies have been proposed as a means to mitigate agricultural contributions to atmospheric carbon by decreasing emissions and sequestering carbon in agricultural soils while increasing water use efficiency and soil quality. However, the effects of no-till versus conventional-till practices on carbon sequestration often vary due to difficulty in quantifying soil carbon as soil properties change with management. Eddy covariance (EC) offers a more accurate method of continuously measuring the total carbon budget and does so without relying on physical soil carbon measurements. The majority of agricultural land in the Midwestern United States is farmed using the corn/soybean rotation, making it an ideal agro-ecosystem to examine the potential of adopting no-till practices on carbon and water balances. In this study, we use EC to compare carbon and water fluxes between continuous no-till and conventional-till corn/soybean sites over several years in east central Illinois. This allows the determination and comparison of 1) net ecosystem exchange (NEE) and net biome production (NEE after accounting for grain usage); 2) water use efficiency; and 3) response to climatic variation, both at short and long time scales, between the two tillage systems. We hypothesize that both carbon uptake and water use efficiency will improve with no-till practices, which in turn will improve crop responses to environmental factors such as drought and heat stress.

  9. Biotic Processes Regulating the Carbon Balance of Desert Ecosystems - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Robert S [UNR; Smith, Stanley D [UNLV; Evans, Dave [WSU; Ogle, Kiona [ASU; Fenstermaker, Lynn [DRI

    2012-12-13

    Our results from the 10-year elevated atmospheric CO{sub 2} concentration study at the Nevada Desert FACE (Free-air CO{sub 2} Enrichment) Facility (NDFF) indicate that the Mojave Desert is a dynamic ecosystem with the capacity to respond quickly to environmental changes. The Mojave Desert ecosystem is accumulating carbon (C), and over the 10-year experiment, C accumulation was significantly greater under elevated [CO{sub 2}] than under ambient, despite great fluctuations in C inputs from year to year and even apparent reversals in which [CO{sub 2}] treatment had greater C accumulations.

  10. The carbon balance and greenhouse effects of the Finnish forest sector at present, in the past and future

    Energy Technology Data Exchange (ETDEWEB)

    Pingoud, K. [Technical Research Centre of Finland, Espoo (Finland)

    1996-12-31

    In this study the greenhouse impact of the total Finnish forest sector was considered, which means that the estimated emissions and sink effects from exported forest products were also included. The forest biomass is and seems to be in the next decades the most important factor in the carbon balance of the total forest sector. The development alternatives of forest industries and waste management practices has still a remarkable influence on the greenhouse impact of the Finnish forest sector. The waste management practices in the future has an important influence on the emissions but the exact net greenhouse impact of the landfills is still uncertain. However, the methane emissions from existing landfills can be reduced essentially by gas recovery. Increased incineration and energy recovery of wood waste (and replacing fossil fuel use by it) is also a future alternative for reducing the greenhouse effects in the forest sector. The sequestration of carbon by increasing the storages of long-lived wood products in use meets difficulties in practice because of all the material losses in wood using chain and the natural removal of old wood products. An important advantage of mechanical wood processing and the succeeding refinement chain is still their relative low use of energy

  11. Balance between carbon gain and loss under long-term drought: impacts on foliar respiration and photosynthesis in Quercus ilex L.

    Science.gov (United States)

    Sperlich, D; Barbeta, A; Ogaya, R; Sabaté, S; Peñuelas, J

    2016-02-01

    Terrestrial carbon exchange is a key process of the global carbon cycle consisting of a delicate balance between photosynthetic carbon uptake and respiratory release. We have, however, a limited understanding how long-term decreases in precipitation induced by climate change affect the boundaries and mechanisms of photosynthesis and respiration. We examined the seasonality of photosynthetic and respiratory traits and evaluated the adaptive mechanism of the foliar carbon balance of Quercus ilex L. experiencing a long-term rainfall-exclusion experiment. Day respiration (Rd) but not night respiration (Rn) was generally higher in the drought treatment leading to an increased Rd/Rn ratio. The limitation of mesophyll conductance (gm) on photosynthesis was generally stronger than stomatal limitation (gs) in the drought treatment, reflected in a lower gm/gs ratio. The peak photosynthetic activity in the drought treatment occurred in an atypical favourable summer in parallel with lower Rd/Rn and higher gm/gs ratios. The plant carbon balance was thus strongly improved through: (i) higher photosynthetic rates induced by gm; and (ii) decreased carbon losses mediated by Rd. Interestingly, photosynthetic potentials (Vc,max, Jmax, and TPU) were not affected by the drought treatment, suggesting a dampening effect on the biochemical level in the long term. In summary, the trees experiencing a 14-year-long drought treatment adapted through higher plasticity in photosynthetic and respiratory traits, so that eventually the atypical favourable growth period was exploited more efficiently.

  12. Cattle methane emission and pasture carbon dioxide balance of a grazed grassland.

    Science.gov (United States)

    McGinn, S M; Beauchemin, K A; Coates, T; McGeough, E J

    2014-05-01

    Grasslands constitute a major land use globally and are a potential sink of atmospheric carbon dioxide (CO). They are also an important habitat for wildlife and a source of feed that supports ruminant livestock production. However, the presence of ruminants grazing these grasslands is also a source of methane (CH) that contributes to buildup of greenhouse gases in the atmosphere. Our study measured enteric CH from 40 confined heifers in 1-ha paddocks using a dispersion model and CO exchange from an adjacent grassland site using a micrometeorological technique. The study was conducted at a mixed prairie grassland located in southern Alberta, Canada. The mean (standard error) CH emission was 189 (± 6) g animal d over four campaigns (over a 3-yr period). The daily averaged CO exchange from the grassland peaked at +2.2 g m h (sink) in early July and declined to negative values (source) in mid-August. Annually, the grazed grassland was either a net sink for carbon (C) at +40 kg C ha or a small source at -7 kg C ha depending on a cattle stocking density of 0.1 or 0.2 animals ha, respectively. However, in basing the exchange on CO equivalence (CO), both stocking densities resulted in the grazed grassland being a source of greenhouse gas of -9 or -338 kg CO ha y. This study illustrates the need to consider the cattle CH emissions and the stocking density when evaluating the environmental sustainability of grazed grasslands.

  13. Soil aggregates, organic matter turnover and carbon balance in a Mediterranean eroded vineyard

    Science.gov (United States)

    Novara, Agata; Lo Papa, Giuseppe; Dazzi, Carmelo; Gristina, Luciano; Cerdà, Artemi

    2014-05-01

    The carbon cycle is being affected by the human impacts (Novara et al., 2011; Yan-Gui et al., 2013), and one of those is the intensification in the soil erosion in agriculture land (Cerdà et al., 2009; García Orenes et al., 2009). Vineyards also are affected by the human activities (Fernández Calviño, 2012). Vineyards in Sicily are cultivated on 110.000 ha, 10% of which on >10% slope. Deficiencies of soil organic matter are typical of the semi arid Mediterranean environment especially where traditional intensive cropping practices are adopted (Novara et al., 2012; 2013). These practices in vineyards could lead soil to intensive erosion processes (Novara et al., 2011). The fate of SOC under erosion processes is difficult to understand because of the influence of the erosion impact on SOC pathway, which depends on the different features of the process involved (detachment, transport and/or deposition). Soil erosion must be considered a net C source (Lal, 2003), as eroded soils have lower net primary productivity (NPP) (Dick and Gregorich, 2004) caused by reduction in the effective rooting depth and all in all determining decline in soil quality. Breakdown of aggregates and soil dispersion expose SOM to microbial/enzymatic processes and chemical soil properties (Dimoyiannis, 2012; Kocyigit and Demirci, 2012). Moreover the light fraction, transported by runoff, is labile and easily mineralized determining CO2 emission in the atmosphere (Jacinthe and Lal, 2004). Therefore, the carbon pool is lower in eroded than in un-eroded soil scapes and the rate of mineralization of soil organic matter is higher in sediments than in original soil. In this survey we show a research conducted on a slope sequence of three soil profiles in an irrigated vineyard located in Sambuca di Sicilia, Italy (UTM33-WGS84: 4169367N; 325011E). The SOC content was measured at depth intervals of 10 cm up to a depth of 60 cm in each pedon. Wet aggregate-size fractions with no prior chemical

  14. Distribution and Orientation of Carbon Fibers in Polylactic Acid Parts Produced by Fused Deposition Modeling

    DEFF Research Database (Denmark)

    Hofstätter, Thomas; W. Gutmann, Ingomar; Koch, Thomas

    2016-01-01

    The aim of this paper is the understanding of the fiber orientation by investigations in respect to the inner configuration of a polylactic acid matrix reinforced with short carbon fibers after a fused deposition modeling extrusion process. The final parts were analyzed by X-ray, tomography, and ......, and magnetic resonance imaging allowing a resolved orientation of the fibers and distribution within the part. The research contributes to the understanding of the fiber orientation and fiber reinforcement of fused deposition modeling parts in additive manufacturing....

  15. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants

    Directory of Open Access Journals (Sweden)

    Abir U Igamberdiev

    2016-07-01

    Full Text Available Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (citrate valve, while malate is accumulated and participates in the redox balance in different cell compartments (via malate valve. This results in malate and citrate frequently being the most accumulated acids in plants. However, the intensity of reactions linked to the conversion of these compounds can cause preferential accumulation of other organic acids, e.g., fumarate or isocitrate, in higher concentrations than malate and citrate. The secondary reactions, associated with the central metabolic pathways, in particularly with the TCA cycle, result in accumulation of other organic acids that are derived from the intermediates of the cycle. They form the additional pools of fixed carbon and stabilize the TCA cycle. Trans-aconitate is formed from citrate or cis-aconitate, accumulation of hydroxycitrate can be linked to metabolism of 2-oxoglutarate, while 4-hydroxy-2-oxoglutarate can be formed from pyruvate and glyoxylate. Glyoxylate, a product of either glycolate oxidase or isocitrate lyase, can be converted to oxalate. Malonate is accumulated at high concentrations in legume plants. Organic acids play a role in plants in providing redox equilibrium, supporting ionic gradients on membranes, and acidification of the extracellular medium.

  16. A novel population balance model to investigate the kinetics of in vitro cell proliferation: part I. Model development.

    Science.gov (United States)

    Fadda, Sarah; Cincotti, Alberto; Cao, Giacomo

    2012-03-01

    In biotechnology and biomedicine reliable models of cell proliferation kinetics need to capture the relevant phenomena taking place during the mitotic cycle. To this aim, a novel mathematical model helpful to investigate the intrinsic kinetics of in vitro culture of adherent cells up to confluence is proposed in this work. Specifically, the attention is focused on the simulation of proliferation (increase of cell number) and maturation (increase of cell size and DNA content) till contact inhibition eventually takes place inside a Petri dish. Accordingly, the proposed model is based on a population balance (PB) approach that allows one to quantitatively describe cell cycle progression through the different phases the cells of the entire population experienced during their own life. In particular, the proposed model has been developed as a 2D, multi-staged, and unstructured PB, by considering a different sub-population of cells for any single phase of the cell cycle. These sub-populations are discriminated through cellular volume and DNA content, that both increase during the mitotic cycle. The adopted mathematical expressions of the transition rates between two subsequent phases and the temporal increase of cell volume and DNA content are thoroughly analyzed and discussed with respect to those ones available in the literature. Specifically, the corresponding uncertainties and pitfalls are pointed out, by also taking into account the difficulties and the limitations involved in the quantitative measurements currently practicable for these biological systems. A novel mathematical expression for contact inhibition in line with the PB model developed is also formulated, along with a proper comparison between modeled and measurable DNA distributions. The strategy for a reliable, independent tuning of the adjustable parameters involved in the proposed model along with its numerical solution is outlined in Part II of this work, where it is also shown how it can be

  17. Severe dry winter affects plant phenology and carbon balance of a cork oak woodland understorey

    Science.gov (United States)

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

    2016-10-01

    Mediterranean climates are prone to a great variation in yearly precipitation. The effects on ecosystem will depend on the severity and timing of droughts. In this study we questioned how an extreme dry winter affects the carbon flux in the understorey of a cork oak woodland? What is the seasonal contribution of understorey vegetation to ecosystem productivity? We used closed-system portable chambers to measure CO2 exchange of the dominant shrub species (Cistus salviifolius, Cistus crispus and Ulex airensis), of the herbaceous layer and on bare soil in a cork oak woodland in central Portugal during the dry winter year of 2012. Shoot growth, leaf shedding, flower and fruit setting, above and belowground plant biomass were measured as well as seasonal leaf water potential. Eddy-covariance and micrometeorological data together with CO2 exchange measurements were used to access the understorey species contribution to ecosystem gross primary productivity (GPP). The herbaceous layer productivity was severely affected by the dry winter, with half of the yearly maximum aboveground biomass in comparison with the 6 years site average. The semi-deciduous and evergreen shrubs showed desynchronized phenophases and lagged carbon uptake maxima. Whereas shallow-root shrubs exhibited opportunistic characteristics in exploiting the understorey light and water resources, deep rooted shrubs showed better water status but considerably lower assimilation rates. The contribution of understorey vegetation to ecosystem GPP was lower during summer with 14% and maximum during late spring, concomitantly with the lowest tree productivity due to tree canopy renewal. The herbaceous vegetation contribution to ecosystem GPP never exceeded 6% during this dry year stressing its sensitivity to winter and spring precipitation. Although shrubs are more resilient to precipitation variability when compared with the herbaceous vegetation, the contribution of the understorey vegetation to ecosystem GPP can

  18. Impact of warming and drought on carbon balance related to wood formation in black spruce

    Science.gov (United States)

    Deslauriers, Annie; Beaulieu, Marilène; Balducci, Lorena; Giovannelli, Alessio; Gagnon, Michel J.; Rossi, Sergio

    2014-01-01

    Background and Aims Wood formation in trees represents a carbon sink that can be modified in the case of stress. The way carbon metabolism constrains growth during stress periods (high temperature and water deficit) is now under debate. In this study, the amounts of non-structural carbohydrates (NSCs) for xylogenesis in black spruce, Picea mariana, saplings were assessed under high temperature and drought in order to determine the role of sugar mobilization for osmotic purposes and its consequences for secondary growth. Methods Four-year-old saplings of black spruce in a greenhouse were subjected to different thermal conditions with respect to the outside air temperature (T0) in 2010 (2 and 5 °C higher than T0) and 2011 (6 °C warmer than T0 during the day or night) with a dry period of about 1 month in June of each year. Wood formation together with starch, NSCs and leaf parameters (water potential and photosynthesis) were monitored from May to September. Key Results With the exception of raffinose, the amounts of soluble sugars were not modified in the cambium even if gas exchange and photosynthesis were greatly reduced during drought. Raffinose increased more than pinitol under a pre-dawn water potential of less than –1 Mpa, presumably because this compound is better suited than polyol for replacing water and capturing free radicals, and its degradation into simple sugar is easier. Warming decreased the starch storage in the xylem as well the available hexose pool in the cambium and the xylem, probably because of an increase in respiration. Conclusions Radial stem growth was reduced during drought due to the mobilization of NSCs for osmotic purposes and due to the lack of cell turgor. Thus plant water status during wood formation can influence the NSCs available for growth in the cambium and xylem. PMID:24950772

  19. Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

    Science.gov (United States)

    Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

    2011-06-01

    and applicability of the fitted NPP-age relationships. These relationships were used to replace the normalized NPP-age relationship used in the original InTEC (Integrated Terrestrial Ecosystem Carbon) model, to improve the accuracy of estimated carbon balance for China's forest ecosystems. With the revised NPP-age relationship, the InTEC model simulated a larger carbon source from 1950-1980 and a larger carbon sink from 1985-2001 for China's forests than the original InTEC model did because of the modification to the age-related carbon dynamics in forests. This finding confirms the importance of considering the dynamics of NPP related to forest age in estimating regional and global terrestrial carbon budgets.

  20. Critical Influences on Carbon Balances and Production in the Man-made Montado Savanna of Portugal

    Science.gov (United States)

    Pereira, J.; Tenhunen, J.; Dinh, N. Q.; Reichstein, M.; Ribeiro, N.

    2005-12-01

    The "montado savanna" of Portugal provides ecosystem services in the form of cork from Quercus suber trees and understory forage for grazing animals. The production system is controlled directly by physical factors along regional climate and hydrological gradients as well as by human influences on fire, grazing and tree population dynamics (planting and plowing for fire control). We present an analysis of carbon and water exchange at montado savanna sites that is based on long-term eddy covariance measurements, ecophysiological field studies and process-based modelling. A pixel-oriented model set up for spatial simulations, estimates gas fluxes between vegetation and the atmosphere separately for the tree and understory compartments (subsequently combining these), allows for herbage growth and LAI development, and predicts physiological gas exchange restrictions (stomatal regulation) and herb dieback in response to reduced water availability over annual courses. Model validation has been carried out via comparisons with eddy covariance observations at the MITRA II site in Evora, Portugal. Ground level observations of ecosystem structure (LAI and tree cover), aerial photography, Landsat images, and MODIS remotely sensed data are utilized to apply the modelling and to estimate fluxes at landscape, regional and continental scales (Mediterranean basin) for similar vegetation. Potential links to tree growth models and socio-economic models are discussed.

  1. Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes.

    Science.gov (United States)

    Wood, Tana E; Cavaleri, Molly A; Reed, Sasha C

    2012-11-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO(2) ) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant climatic change. Here we present a contemporary synthesis of the existing data and what they suggest about how tropical forests will respond to increasing temperatures. Our goals were to: (i) determine whether there is enough evidence to support the conclusion that increased temperature will affect tropical forest C balance; (ii) if there is sufficient evidence, determine what direction this effect will take; and, (iii) establish what steps should to be taken to resolve the uncertainties surrounding tropical forest responses to increasing temperatures. We approach these questions from a mass-balance perspective and therefore focus primarily on the effects of temperature on inputs and outputs of C, spanning microbial- to ecosystem-scale responses. We found that, while there is the strong potential for temperature to affect processes related to C cycling and storage in tropical forests, a notable lack of data combined with the physical, biological and chemical diversity of the forests themselves make it difficult to resolve this issue with certainty. We suggest a variety of experimental approaches that could help elucidate how tropical forests will respond to warming, including large-scale in situ manipulation experiments, longer term field experiments, the incorporation of a range of scales in the investigation of warming effects (both spatial and temporal), as well as the inclusion of a diversity of tropical forest sites. Finally, we highlight areas of tropical forest research where notably few data are available, including temperature effects on: nutrient cycling

  2. Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes

    Science.gov (United States)

    Wood, Tana E.; Cavaleri, Molly A.; Reed, Sasha C.

    2012-01-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO2) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant climatic change. Here we present a contemporary synthesis of the existing data and what they suggest about how tropical forests will respond to increasing temperatures. Our goals were to: (i) determine whether there is enough evidence to support the conclusion that increased temperature will affect tropical forest C balance; (ii) if there is sufficient evidence, determine what direction this effect will take; and, (iii) establish what steps should to be taken to resolve the uncertainties surrounding tropical forest responses to increasing temperatures. We approach these questions from a mass-balance perspective and therefore focus primarily on the effects of temperature on inputs and outputs of C, spanning microbial- to ecosystem-scale responses. We found that, while there is the strong potential for temperature to affect processes related to C cycling and storage in tropical forests, a notable lack of data combined with the physical, biological and chemical diversity of the forests themselves make it difficult to resolve this issue with certainty. We suggest a variety of experimental approaches that could help elucidate how tropical forests will respond to warming, including large-scale in situ manipulation experiments, longer term field experiments, the incorporation of a range of scales in the investigation of warming effects (both spatial and temporal), as well as the inclusion of a diversity of tropical forest sites. Finally, we highlight areas of tropical forest research where notably few data are available, including temperature effects on: nutrient cycling

  3. Subalpine grassland carbon balance during 7 years of increased atmospheric N deposition

    Science.gov (United States)

    Volk, Matthias; Enderle, Jan; Bassin, Seraina

    2016-07-01

    Air pollution agents interact when affecting biological sinks for atmospheric CO2, e.g., the soil organic carbon (SOC) content of grassland ecosystems. Factors favoring plant productivity, like atmospheric N deposition, are usually considered to favor SOC storage. In a 7-year experiment in subalpine grassland under N- and O3-deposition treatment, we examined C fluxes and pools. Total N deposition was 4, 9, 14, 29 and 54 kg N ha-1 yr-1 (N4, N9, etc.); annual mean phytotoxic O3 dose was 49, 65 and 89 mmol m-2 projected leaf area. We hypothesized that between years SOC of this mature ecosystem would not change in control treatments and that effects of air pollutants are similar for plant yield, net ecosystem productivity (NEP) and SOC content, leading to SOC content increasing with N deposition. Cumulative plant yield showed a significant N and N × N effect (+38 % in N54) but no O3 effect. In the control treatment SOC increased significantly by 9 % in 7 years. Cumulative NEP did show a strong, hump-shaped response pattern to N deposition with a +62 % increase in N14 and only +39 % increase in N54 (N effect statistically not significant, N × N interaction not testable). SOC had a similar but not significant response to N, with highest C gains at intermediate N deposition rates, suggesting a unimodal response with a marginal (P = 0.09) N × N interaction. We assume the strong, pollutant-independent soil C sink developed as a consequence of the management change from grazing to cutting. The non-parallel response of SOC and NEP compared to plant yield under N deposition is likely the result of increased respiratory SOC losses, following mitigated microbial N-limitation or priming effects, and a shift in plant C allocation leading to smaller C input from roots.

  4. Application of a generalized likelihood function for parameter inference of a carbon balance model using multiple, joint constraints

    Science.gov (United States)

    Hammerle, Albin; Wohlfahrt, Georg; Schoups, Gerrit

    2014-05-01

    Advances in automated data collection systems enabled ecologists to collect enormous amounts of varied data. Data assimilation (or data model synthesis) is one way to make sense of this mass of data. Given a process model designed to learn about ecological processes these data can be integrated within a statistical framework for data interpretation and extrapolation. Results of such a data assimilation framework clearly depend on the information content of the observed data, on the associated uncertainties (data uncertainties, model structural uncertainties and parameter uncertainties) and underlying assumptions. Parameter estimation is usually done by minimizing a simple least squares objective function with respect to the model parameters - presuming Gaussian, independent and homoscedastic errors (formal approach). Recent contributions to the (ecological) literature, however, have questioned the validity of this approach when confronted with significant errors and uncertainty in the model forcing (inputs) and model structure. Very often residual errors are non-Gaussian, correlated and heteroscedastic. Thus these error sources have to be considered and residual-errors have to be described in a statistically correct fashion order to draw statistically sound conclusions about parameter- and model predictive-uncertainties. We examined the effects of a generalized likelihood (GL) function on the parameter estimation of a carbon balance model. Compared with the formal approach, the GL function allows for correlation, non-stationarity and non-normality of model residuals. Carbon model parameters have been constrained using three different datasets, each of them modelled by its own GL function. As shown in literature the use of different datasets for parameter estimation reduces the uncertainty in model parameters and model predictions and does allow for a better quantification and for more insights into model processes.

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

    NARCIS (Netherlands)

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

    2015-01-01

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

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  7. Implications of future disturbance regimes on the carbon balance of Canada's managed forest (2010-2100)

    Energy Technology Data Exchange (ETDEWEB)

    Metsaranta, J.M.; Kurz, W.A.; Neilson, E.T.; Stinson, G. (Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, Victoria, BC (Canada))

    2010-11-15

    Recent increases in fire and insect disturbances have contributed to a transition of Canada's managed forest carbon balance from sink to source. Further increases in area burned could contribute positive feedback to climate change. We made probabilistic forecasts of the recovery of C sinks in Canada's managed forest between 2010 and 2100 under two assumptions about future area burned by wildfire: (1) no increase relative to levels observed in the last half of the 20th century and (2) linear increases by a factor of two or four (depending on region) from 2010 to 2100. Recovery of strong C sinks in Canada's managed forest will be delayed until at least the 2030s because of insect outbreaks, even if predicted increases in area annually burned do not occur. After 2050, our simulations project an annual probability of a sink near 70% with no increase in area burned and 35% with increasing area burned. All simulations project a cumulative C source from 2010-2100, even if annual area burned does not increase. If the sink strength of terrestrial ecosystems is reduced because of increasing natural disturbances, then it will become more difficult to achieve global atmospheric CO{sub 2} stabilization targets.

  8. Carbon balance of a subarctic meadow under 3 r{ C warming - unravelling respiration}

    Science.gov (United States)

    Silvennoinen, Hanna; Bárcena, Téresa G.; Moni, Christophe; Szychowski, Marcin; Rajewicz, Paulina; Höglind, Mats; Rasse, Daniel P.

    2016-04-01

    Boreal and arctic terrestrial ecosystems are central to the climate change debate, as the warming is expected to be disproportionate as compared to world averages. Northern areas contain large terrestrial carbon (C) stocks further increasing the interest in the C cycle's fate in changing climate. In 2013, we started an ecosystem warming experiment at a meadow in Eastern Finnmark, NE Norway. The meadow was on a clay soil and its vegetation was common meadow grasses and clover. Typical local agronomy was applied. The study site featured ten 4m-wide hexagonal plots, five control and five actively warmed plots in randomized complete block design. Each of the warmed plots was continuously maintained 3 ° C above its associated control plot with infrared heaters controlled by canopy thermal sensors. In 2014-2015, we measured net ecosystem exchange (NEE) and respiration twice per week during growth seasons from preinstalled collars of each site with dynamic, temperature-controlled chambers combined to an infrared analyzer. Despite warming-induced differences in yield, species composition and root biomass, neither the NEE nor the respiration responded to the warming, all sites remaining equal sinks for C. Following this observation, we carried out an additional experiment in 2015 where we aimed at partitioning the total CO2 flux to microbial and plant respiration as well as at recording the growth season variation of those parameters in situ. Here, we used an approach based on natural abundances of 13C. The δ13C signature of both autotrophic plant respiration and heterotrophic microbial respiration were obtained in targeted incubations (Snell et al. 2014). Then, the δ13C -signature of the total soil respiration was determined in the field by Keeling approach with dynamic dark chambers combined to CRDS. Proportions of autotrophic and heterotrophic components in total soil respiration were then derived based on 13C mixing model. Incubations were repeated at early, mid and

  9. A large column analog experiment of stable isotope variations during reactive transport: II. Carbon mass balance, microbial community structure and predation

    Science.gov (United States)

    Druhan, Jennifer L.; Bill, Markus; Lim, HsiaoChien; Wu, Cindy; Conrad, Mark E.; Williams, Kenneth H.; DePaolo, Donald J.; Brodie, Eoin L.

    2014-01-01

    Here we report a combined analysis of carbon mass balance based on isotopic labeling and microbiological characterization during organic carbon stimulated bioreduction of a subsurface sediment in a large laboratory column experimental system. This combination of approaches allows quantification of both the cycling of carbon through multiple redox pathways and the associated spatial and temporal evolution of bacterial communities in response to this nutrient source. Carbon isotope mass balance facilitated by the use of 13C-labeled acetate as the electron donor showed evidence for a net loss of sediment organic carbon over the course of the amendment experiment. Furthermore, these data clearly demonstrated a source of isotopically labeled inorganic carbon that was not attributable to primary metabolism by acetate-oxidizing microorganisms. Fluid samples collected weekly over the duration of the 43-day amendment at composition by pyrosequencing of ribosomal RNA genes. The microbial community composition was transient, with distinct occurrences of Azoarcus, Geobacter and multiple sulfate reducing species over the course of the experiment. In combination with DNA sequencing data, the anomalous carbon cycling process is shown to occur exclusively during the period of predominant Geobacter species growth. Pyrosequencing indicated, and targeted cloning and sequencing confirmed the presence of several bacteriovorous protozoa, including species of the Breviata, Planococcus and Euplotes genera. Cloning and qPCR analysis demonstrated that Euplotes species were most abundant and displayed a growth trajectory that closely followed that of the Geobacter population. These results suggest a previously undocumented secondary turnover of biomass carbon related to protozoan grazing that was not sufficiently prevalent to be observed in bulk concentrations of carbon species in the system, but was clearly identified in the partitioning of carbon isotopes. This study demonstrates evidence

  10. Mass, energy and material balances of SRF production process. Part 1: SRF produced from commercial and industrial waste.

    Science.gov (United States)

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

    2014-08-01

    This paper presents the mass, energy and material balances of a solid recovered fuel (SRF) production process. The SRF is produced from commercial and industrial waste (C&IW) through mechanical treatment (MT). In this work various streams of material produced in SRF production process are analyzed for their proximate and ultimate analysis. Based on this analysis and composition of process streams their mass, energy and material balances are established for SRF production process. Here mass balance describes the overall mass flow of input waste material in the various output streams, whereas material balance describes the mass flow of components of input waste stream (such as paper and cardboard, wood, plastic (soft), plastic (hard), textile and rubber) in the various output streams of SRF production process. A commercial scale experimental campaign was conducted on an MT waste sorting plant to produce SRF from C&IW. All the process streams (input and output) produced in this MT plant were sampled and treated according to the CEN standard methods for SRF: EN 15442 and EN 15443. The results from the mass balance of SRF production process showed that of the total input C&IW material to MT waste sorting plant, 62% was recovered in the form of SRF, 4% as ferrous metal, 1% as non-ferrous metal and 21% was sorted out as reject material, 11.6% as fine fraction, and 0.4% as heavy fraction. The energy flow balance in various process streams of this SRF production process showed that of the total input energy content of C&IW to MT plant, 75% energy was recovered in the form of SRF, 20% belonged to the reject material stream and rest 5% belonged with the streams of fine fraction and heavy fraction. In the material balances, mass fractions of plastic (soft), plastic (hard), paper and cardboard and wood recovered in the SRF stream were 88%, 70%, 72% and 60% respectively of their input masses to MT plant. A high mass fraction of plastic (PVC), rubber material and non

  11. Mass, energy and material balances of SRF production process. Part 2: SRF produced from construction and demolition waste.

    Science.gov (United States)

    Nasrullah, Muhammad; Vainikka, Pasi; Hannula, Janne; Hurme, Markku; Kärki, Janne

    2014-11-01

    In this work, the fraction of construction and demolition waste (C&D waste) complicated and economically not feasible to sort out for recycling purposes is used to produce solid recovered fuel (SRF) through mechanical treatment (MT). The paper presents the mass, energy and material balances of this SRF production process. All the process streams (input and output) produced in MT waste sorting plant to produce SRF from C&D waste are sampled and treated according to CEN standard methods for SRF. Proximate and ultimate analysis of these streams is performed and their composition is determined. Based on this analysis and composition of process streams their mass, energy and material balances are established for SRF production process. By mass balance means the overall mass flow of input waste material stream in the various output streams and material balances mean the mass flow of components of input waste material stream (such as paper and cardboard, wood, plastic (soft), plastic (hard), textile and rubber) in the various output streams of SRF production process. The results from mass balance of SRF production process showed that of the total input C&D waste material to MT waste sorting plant, 44% was recovered in the form of SRF, 5% as ferrous metal, 1% as non-ferrous metal, and 28% was sorted out as fine fraction, 18% as reject material and 4% as heavy fraction. The energy balance of this SRF production process showed that of the total input energy content of C&D waste material to MT waste sorting plant, 74% was recovered in the form of SRF, 16% belonged to the reject material and rest 10% belonged to the streams of fine fraction and heavy fraction. From the material balances of this process, mass fractions of plastic (soft), paper and cardboard, wood and plastic (hard) recovered in the SRF stream were 84%, 82%, 72% and 68% respectively of their input masses to MT plant. A high mass fraction of plastic (PVC) and rubber material was found in the reject material

  12. Long-term nutrient fertilization and the carbon balance of permanent grassland: any evidence for sustainable intensification?

    Science.gov (United States)

    Fornara, Dario A.; Wasson, Elizabeth-Anne; Christie, Peter; Watson, Catherine J.

    2016-09-01

    Sustainable grassland intensification aims to increase plant yields while maintaining the ability of soil to act as a sink rather than sources of atmospheric CO2. High biomass yields from managed grasslands, however, can be only maintained through long-term nutrient fertilization, which can significantly affect soil carbon (C) storage and cycling. Key questions remain about (1) how long-term inorganic vs. organic fertilization influences soil C stocks, and (2) how soil C gains (or losses) contribute to the long-term C balance of managed grasslands. Using 43 years of data from a permanent grassland experiment, we show that soils not only act as significant C sinks but have not yet reached C saturation. Even unfertilized control soils showed C sequestration rates of 0.35 Mg C ha-1 yr-1 (i.e. 35 g C m-2 yr-1; 0-15 cm depth) between 1970 and 2013. High application rates of liquid manure (i.e. cattle slurry) further increased soil C sequestration to 0.86 Mg C ha-1 yr-1 (i.e. 86 g C m-2 yr-1) and a key cause of this C accrual was greater C inputs from cattle slurry. However, average coefficients of slurry-C retention in soils suggest that 85 % of C added yearly through liquid manure is lost possibly via CO2 fluxes and organic C leaching. Inorganically fertilized soils (i.e. NPK) had the lowest C-gain efficiency (i.e. unit of C gained per unit of N added) and lowest C sequestration (similar to control soils). Soils receiving cattle slurry showed higher C-gain and N-retention efficiencies compared to soils receiving NPK or pig slurry. We estimate that net rates of CO2-sequestration in the top 15 cm of the soil can offset 9-25 % of GHG (greenhouse gas) emissions from intensive management. However, because of multiple GHG sources associated with livestock farming, the net C balance of these grasslands remains positive (9-12 Mg CO2-equivalent ha-1 yr-1), thus contributing to climate change. Further C-gain efficiencies (e.g. reduced enteric fermentation and use of feed

  13. Mice and Men Environmental Balance, Parts Three and Four of an Integrated Science Sequence, Teacher's Guide, 1970 Edition.

    Science.gov (United States)

    Portland Project Committee, OR.

    This teacher's guide contains parts three and four of the four-part first year Portland Project, a three-year secondary integrated science curriculum sequence. Part three of the guide deals with topics such as the cell, reproduction, embryology, genetics, genetic diseases, genetics and change, populations, effects of density on populations,…

  14. Carbon dioxide and the stomatal control of water balance and photosynthesis in higher plants. Progress report, July 1, 1990--June 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    1992-07-01

    Research continued into the investigation of the effects of carbon dioxide on stomatal control of water balance and photosynthesis in higher plants. Topics discussed this period include a method of isolating a sufficient number of guard cell chloroplasts for biochemical studies by mechanical isolation of epidermal peels; the measurement of stomatal apertures with a digital image analysis system; development of a high performance liquid chromatography method for quantification of metabolites in guard cells; and genetic control of stomatal movements in Pima cotton. (CBS)

  15. Rotary Bed Reactor for Chemical-Looping Combustion with Carbon Capture. Part 2: Base Case and Sensitivity Analysis

    KAUST Repository

    Zhao, Zhenlong

    2013-01-17

    Part 1 (10.1021/ef3014103) of this series describes a new rotary reactor for gas-fueled chemical-looping combustion (CLC), in which, a solid wheel with microchannels rotates between the reducing and oxidizing streams. The oxygen carrier (OC) coated on the surfaces of the channels periodically adsorbs oxygen from air and releases it to oxidize the fuel. A one-dimensional model is also developed in part 1 (10.1021/ef3014103). This paper presents the simulation results based on the base-case design parameters. The results indicate that both the fuel conversion efficiency and the carbon separation efficiency are close to unity. Because of the relatively low reduction rate of copper oxide, fuel conversion occurs gradually from the inlet to the exit. A total of 99.9% of the fuel is converted within 75% of the channel, leading to 25% redundant length near the exit, to ensure robustness. In the air sector, the OC is rapidly regenerated while consuming a large amount of oxygen from air. Velocity fluctuations are observed during the transition between sectors because of the complete reactions of OCs. The gas temperature increases monotonically from 823 to 1315 K, which is mainly determined by the solid temperature, whose variations with time are limited within 20 K. The overall energy in the solid phase is balanced between the reaction heat release, conduction, and convective cooling. In the sensitivity analysis, important input parameters are identified and varied around their base-case values. The resulting changes in the model-predicted performance revealed that the most important parameters are the reduction kinetics, the operating pressure, and the feed stream temperatures. © 2012 American Chemical Society.

  16. Space–time dynamics of carbon and environmental parameters related to carbon dioxide emissions in the Buor-Khaya Bay and adjacent part of the Laptev Sea

    Directory of Open Access Journals (Sweden)

    I. P. Semiletov

    2013-09-01

    Full Text Available This study aims to improve understanding of carbon cycling in the Buor-Khaya Bay (BKB and adjacent part of the Laptev Sea by studying the inter-annual, seasonal, and meso-scale variability of carbon and related hydrological and biogeochemical parameters in the water, as well as factors controlling carbon dioxide (CO2 emission. Here we present data sets obtained on summer cruises and winter expeditions during 12 yr of investigation. Based on data analysis, we suggest that in the heterotrophic BKB area, input of terrestrially borne organic carbon (OC varies seasonally and inter-annually and is largely determined by rates of coastal erosion and river discharge. Two different BKB sedimentation regimes were revealed: Type 1 (erosion accumulation and Type 2 (accumulation. A Type 1 sedimentation regime occurs more often and is believed to be the quantitatively most important mechanism for suspended particular matter (SPM and particulate organic carbon (POC delivery to the BKB. The mean SPM concentration observed in the BKB under a Type 1 regime was one order of magnitude greater than the mean concentration of SPM (~ 20 mg L−1 observed along the Lena River stream in summer 2003. Loadings of the BKB water column with particulate material vary by more than a factor of two between the two regimes. Higher partial pressure of CO2 (pCO2, higher concentrations of nutrients, and lower levels of oxygen saturation were observed in the bottom water near the eroded coasts, implying that coastal erosion and subsequent oxidation of eroded organic matter (OM rather than the Lena River serves as the predominant source of nutrients to the BKB. Atmospheric CO2 fluxes from the sea surface in the BKB vary from 1 to 95 mmol m−2 day−1 and are determined by specific features of hydrology and wind conditions, which change spatially, seasonally, and inter-annually. Mean values of CO2 emission from the shallow Laptev Sea were similar in September 1999 and 2005 (7.2 and 7

  17. Integrating Remote Sensing, Field Observations, and Models to Understand Disturbance and Climate Effects on the Carbon Balance of the West Coast U.S.

    Energy Technology Data Exchange (ETDEWEB)

    B.E. Law; D. Turner; M. Goeckede

    2010-06-01

    GOAL: To develop and apply an approach to quantify and understand the regional carbon balance of the west coast states for the North American Carbon Program. OBJECTIVE: As an element of NACP research, the proposed investigation is a two pronged approach that derives and evaluates a regional carbon (C) budget for Oregon, Washington, and California. Objectives are (1) Use multiple data sources, including AmeriFlux data, inventories, and multispectral remote sensing data to investigate trends in carbon storage and exchanges of CO2 and water with variation in climate and disturbance history; (2) Develop and apply regional modeling that relies on these multiple data sources to reduce uncertainty in spatial estimates of carbon storage and NEP, and relative contributions of terrestrial ecosystems and anthropogenic emissions to atmospheric CO2 in the region; (3) Model terrestrial carbon processes across the region, using the Biome-BGC terrestrial ecosystem model, and an atmospheric inverse modeling approach to estimate variation in rate and timing of terrestrial uptake and feedbacks to the atmosphere in response to climate and disturbance. APPROACH: In performing the regional analysis, the research plan for the bottom-up approach uses a nested hierarchy of observations that include AmeriFlux data (i.e., net ecosystem exchange (NEE) from eddy covariance and associated biometric data), intermediate intensity inventories from an extended plot array partially developed from the PI's previous research, Forest Service FIA and CVS inventory data, time since disturbance, disturbance type, and cover type from Landsat developed in this study, and productivity estimates from MODIS algorithms. The BIOME-BGC model is used to integrate information from these sources and quantify C balance across the region. The inverse modeling approach assimilates flux data from AmeriFlux sites, high precision CO2 concentration data from AmeriFlux towers and four new calibrated CO2 sites

  18. Mechanical performance of carbon-epoxy laminates. Part I: quasi-static and impact bending properties

    Directory of Open Access Journals (Sweden)

    José Ricardo Tarpani

    2006-06-01

    Full Text Available In Part I of this study, quasi-static and impact bending properties of four aeronautical grade carbon-epoxy laminates have been determined and compared. Materials tested were unidirectional cross-ply (tape and bidirectional woven textile (fabric carbon fiber lay-up architectures, impregnated with standard and rubber-toughened resins, respectively, giving rise to 1.5 mm-thick laminates. Quasi-static mechanical properties assessed in transversal mode loading were modulus of elasticity, flexural strength and tenacity at the maximum load, whereas the net absorbed energy was determined under translaminar impact conditions. Two-dimensional woven carbon fiber reinforcements embedded in a rubber-toughened matrix presented the best mechanical performance under static loading. Under dynamic loading conditions, woven fiber fabric pre-forms were favorably sensitive to increasing impact energies regardless the nature of the employed epoxy resin. However, it was concluded that great care should be taken with this material within the low energy impact regimen.

  19. Paleodata-model integration reveals uncertain boreal forest carbon balance due to rapid recent fire regime change

    Science.gov (United States)

    Kelly, R.; Genet, H.; McGuire, D.; Hu, F.

    2013-12-01

    Climate warming is expected to increase the frequency and severity of natural fires in the boreal forest biome. Boreal forests represent >30% of terrestrial carbon (C) stocks, and fire is a key component of the C cycle in these ecosystems. However, predictions of fire-regime change face substantial uncertainty, largely because complex fire-climate-vegetation interactions are poorly characterized in brief observational records. Furthermore, previous studies suggest that model projections of future C dynamics are sensitive to assumptions about the prehistoric fire regime. Paleofire reconstructions offer valuable insights to address these limitations. We collected 14 lake-sediment cores from the Yukon Flats, Alaska to elucidate patterns of long-term environmental change. We then converted fire-regime reconstructions from these data to input drivers for the Dynamic Organic Soils version of the Terrestrial Ecosystem Model (DOS-TEM). Combined with simulated paleoclimate from an Earth System Model and CO2 data from ice core analysis, these 'paleo-forcing' data allowed us to model past changes in ecosystem C storage in our study area to (1) assess the relative importance of climate, atmospheric CO2 concentration, and fire in driving C dynamics of the past millennium, and (2) evaluate the effect of assumptions about prehistoric fire regime on predictions of current and future boreal-forest C balance. Fire-regime variations were the dominant control on simulated C storage, producing fluctuations of ~3 kg C/m2 (~25% of total ecosystem C) on centennial timescales. By comparison, climate and CO2 concentration played minor roles. Fire frequency shifts were particularly influential, suggesting that the role of fire in dictating stand age distribution at the landscape scale is of paramount importance to net C dynamics. That shifts in fire-regime were responsible for large and rapid losses of C in the past emphasizes the importance of incorporating fire into methodologies that

  20. Flexibility, compromise and opportunity: Students' perceptions of balancing part-time work with a full-time business degree.

    OpenAIRE

    Evans, C.; Gbadamosi, Gbola; Richardson, M

    2014-01-01

    Amidst the growing importance of employability in higher education, this study explores and identifies the motivations behind full-time university students engaging in part-time employment during term time, how students cope with simultaneously managing the two activities and how part-time working influences their career aspirations. Semi-structured interviews are used to obtain data from a sample of 30 business degree students at a UK university. The findings confirm previous studies, that f...

  1. Academic Plate Spinning: the Difficulties of Balancing Full Time Degree Study With a Part-Time Job

    OpenAIRE

    Richardson, Mark; Evans, Carl; Gbadamosi, Gbolahan

    2013-01-01

    The study examined full-time students engaged in part-time work during term time. A qualitative approach was used to examine how students cope with simultaneously managing the two activities, and how part-time working affects their academic study. Semi-structured interviews were used to obtain data from a sample of 30 undergraduate business students. The findings confirm that students merely satisfice many aspects of their lives, with reading time and assignment preparation being key areas th...

  2. Climate of the Greenland ice sheet using a high-resolution climate model – Part 2: Near-surface climate and energy balance

    Directory of Open Access Journals (Sweden)

    J. Ettema

    2010-12-01

    Full Text Available The spatial variability of near-surface variables and surface energy balance components over the Greenland ice sheet are presented, using the output of a regional atmospheric climate model for the period 1958–2008. The model was evaluated in Part 1 of this paper.

    The near-surface temperature over the ice sheet is affected by surface elevation, latitude, longitude, large-scale and small-scale advection, occurrence of summer melt and mesoscale topographical features. The atmospheric boundary layer is characterised by a strong temperature inversion, due to continuous longwave cooling of the surface. In combination with a gently sloping surface the radiative loss maintains a persistent katabatic wind. This radiative heat loss is mainly balanced by turbulent sensible heat transport towards the surface. In summer, the surface is near radiative balance, resulting in lower wind speeds. Absorption of shortwave radiation and a positive subsurface heat flux due to refreezing melt water are heat sources for surface sublimation and melt.

    The strongest temperature deficits (>13 °C are found on the northeastern slopes, where the strongest katabatic winds (>9 m s−1 and lowest relative humidity (<65% occur. Due to strong large scale winds, clear sky (cloud cover <0.5 and a concave surface, a continuous supply of cold dry air is generated, which enhances the katabatic forcing and suppresses subsidence of potentially warmer free atmosphere air.

  3. Synthesis of Remote Sensing and Field Observations to Model and Understand Disturbance and Climate Effects on the Carbon Balance of Oregon & Northern California

    Energy Technology Data Exchange (ETDEWEB)

    Beverly Law; David Turner; Warren Cohen; Mathias Goeckede

    2008-05-22

    The goal is to quantify and explain the carbon (C) budget for Oregon and N. California. The research compares "bottom -up" and "top-down" methods, and develops prototype analytical systems for regional analysis of the carbon balance that are potentially applicable to other continental regions, and that can be used to explore climate, disturbance and land-use effects on the carbon cycle. Objectives are: 1) Improve, test and apply a bottom up approach that synthesizes a spatially nested hierarchy of observations (multispectral remote sensing, inventories, flux and extensive sites), and the Biome-BGC model to quantify the C balance across the region; 2) Improve, test and apply a top down approach for regional and global C flux modeling that uses a model-data fusion scheme (MODIS products, AmeriFlux, atmospheric CO2 concentration network), and a boundary layer model to estimate net ecosystem production (NEP) across the region and partition it among GPP, R(a) and R(h). 3) Provide critical understanding of the controls on regional C balance (how NEP and carbon stocks are influenced by disturbance from fire and management, land use, and interannual climate variation). The key science questions are, "What are the magnitudes and distributions of C sources and sinks on seasonal to decadal time scales, and what processes are controlling their dynamics? What are regional spatial and temporal variations of C sources and sinks? What are the errors and uncertainties in the data products and results (i.e., in situ observations, remote sensing, models)?

  4. Ash recycling to spruce and beech stands effects on nutrients, growth, nitrogen dynamics and carbon balance; Askaaterfoering till gran- och bokbestaand - effekter paa naering, tillvaext, kvaevedynamik och kolbalans

    Energy Technology Data Exchange (ETDEWEB)

    Thelin, Gunnar

    2006-03-15

    Ash recycling is an important part in a modern, sustainable forestry, especially in whole-tree harvest systems. Nutrients lost at harvest are returned to the forest with the wood-ash. In the project the effects of ash treatment on needle and leaf chemistry, tree growth, soil chemistry, soil water chemistry, and carbon and nitrogen dynamics were studied on 23 Norway spruce sites in south-western Sweden and in ten European beech sites in Scania, southern Sweden. On some of the sites there were previously established ash recycling experiments, but on a majority of the sites ash recycling was performed without experimental lay-out and ash and control plots were established afterwards. The most common dose was two tons of self hardened crushed wood-ash and two tons of Mg-lime. On average seven to eight years after ash recycling the results were 1. increased exchangeable stores of base cations in the soil in the beech and the spruce stands 2. increased base saturation in the beech and the spruce stands and increased BC/Al in the spruce stands 3. increased concentrations and ratios to N of P, Ca, Zn, and S in the needles, the increased P-values are especially important since P is close to or below deficiency levels in a majority of the spruce stands 4. decreased K-concentration in the beech leaves 5. increased tree growth with on average 14 % in the ash treated spruce stands compared to the control plots 6. increased carbon and nitrogen amounts in the biomass in the spruce stands 7. tendencies towards increased amounts of carbon and nitrogen in the soil in the beech stands and no effect in the soil in the spruce stands 8. increased concentrations of Ca, Mg, and SO{sub 4} and no effect on ANC in the soil water 9. no effect on potential net mineralization but increased potential nitrification rates 10. decreased concentration of nitrate in the soil water in the beech stands and no effect in the spruce stands 11. lower system N losses in the beech stands and possibly in the

  5. Components of near-surface energy balance derived from satellite soundings – Part 1: Net available energy

    Directory of Open Access Journals (Sweden)

    K. Mallick

    2014-08-01

    Full Text Available This paper introduces a relatively simple method for recovering global fields of near-surface net available energy (the sum of the sensible and latent heat flux or the difference between the net radiation and surface heat accumulation using satellite visible and infra-red products derived from the AIRS (Atmospheric Infrared Sounder and MODIS (MOderate Resolution Imaging Spectroradiometer platforms. The method focuses on first specifying net surface radiation by considering its various shortwave and longwave components. This was then used in a surface energy balance equation in conjunction with satellite day–night surface temperature difference to derive 12 h discrete time estimates of surface, system heat capacity and heat accumulation, leading directly to retrieval for surface net available energy. Both net radiation and net available energy estimates were evaluated against ground truth data taken from 30 terrestrial tower sites affiliated to the FLUXNET network covering 7 different biome classes. This revealed a relatively good agreement between the satellite and tower data, with a pooled root mean square deviation of 98 and 72 W m−2 for net radiation and net available energy, respectively, although both quantities were underestimated by approximately 25 and 10%, respectively relative to the tower observations. Analysis of the individual shortwave and longwave components of the net radiation revealed the downwelling shortwave radiation to be the main source of this systematic underestimation.

  6. Carbon Observations from Geostationary Earth Orbit as Part of an Integrated Observing System for Atmospheric Composition

    Science.gov (United States)

    Edwards, D. P.

    2015-12-01

    This presentation describes proposed satellite carbon measurements from the CHRONOS mission. The primary goal of this experiment is to measure the atmospheric pollutants carbon monoxide (CO) and methane (CH4) from geostationary orbit, with hourly observations of North America at high spatial resolution. CHRONOS observations would provide measurements not currently available or planned as part of a surface, suborbital and satellite integrated observing system for atmospheric composition over North America. Carbon monoxide is produced by combustion processes such as urban activity and wildfires, and serves as a proxy for other combustion pollutants that are not easily measured. Methane has diverse anthropogenic sources ranging from fossil fuel production, animal husbandry, agriculture and waste management. The impact of gas exploration in the Western States of the USA and oil extraction from the Canadian tar sands will be particular foci of the mission, as will the poorly-quantified natural CH4 emissions from wetlands and thawing permafrost. In addition to characterizing pollutant sources, improved understanding of the domestic CH4 budget is a priority for policy decisions related to short-lived climate forcers. A primary motivation for targeting CO is its value as a tracer of atmospheric pollution, and CHRONOS measurements will provide insight into local and long-range transport across the North American continent, as well as the processes governing the entrainment and venting of pollution in and out of the planetary boundary layer. As a result of significantly improved characterization of diurnal changes in atmospheric composition, CHRONOS observations will find direct societal applications for air quality regulation and forecasting. We present a quantification of this expected improvement in the prediction of near-surface concentrations when CHRONOS measurements are used in Observation System Simulation Experiments (OSSEs). If CHRONOS and the planned NASA Earth

  7. The seasonal carbon and water balances of the Cerrado environment of Brazil: Past, present, and future influences of land cover and land use

    Science.gov (United States)

    Arantes, Arielle Elias; Ferreira, Laerte G.; Coe, Michael T.

    2016-07-01

    increasing global demand for agricultural products and the insufficient protected areas in the Cerrado (with a significant area of remaining native vegetation in privately owned lands that may be legally deforested), our analyses suggest that potential future changes to the water and carbon balances are likely to be highly significant in the severely threatened Cerrado biome. On the other hand, our results also suggest that the recovery of degraded pastures can have a positive impact on climate, due to the higher rates of carbon sequestration and water transfer to the atmosphere.

  8. FROM ZERO-DIMENSIONAL TO 2-DIMENSIONAL CARBON NANOMATERIALS - part I: TYPES OF CNs

    Directory of Open Access Journals (Sweden)

    Cătălin IANCU

    2012-05-01

    Full Text Available In recent years, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nanotechnology which is called carbon-related nanomaterials. In this review paper are presented some of the most important developments in the synthesis, properties, and applications of low-dimensional carbon nanomaterials. The synthesis techniques are used to produce specific kinds of low-dimensional carbon nanomaterials such as zero-dimensional CNs (including fullerene, carbon-encapsulated metal nanoparticles, nanodiamond, and onion-like carbons, one-dimensional carbon nanomaterials (including carbon nanofibers and carbon nanotubes, and two-dimensional carbon nanomaterials (including graphene and carbon nanowalls.

  9. Evaluating options for balancing the water-electricity nexus in California: Part 2--greenhouse gas and renewable energy utilization impacts.

    Science.gov (United States)

    Tarroja, Brian; AghaKouchak, Amir; Sobhani, Reza; Feldman, David; Jiang, Sunny; Samuelsen, Scott

    2014-11-01

    A study was conducted to compare the technical potential and effectiveness of different water supply options for securing water availability in a large-scale, interconnected water supply system under historical and climate-change augmented inflow and demand conditions. Part 2 of the study focused on determining the greenhouse gas and renewable energy utilization impacts of different pathways to stabilize major surface reservoir levels. Using a detailed electric grid model and taking into account impacts on the operation of the water supply infrastructure, the greenhouse gas emissions and effect on overall grid renewable penetration level was calculated for each water supply option portfolio that successfully secured water availability from Part 1. The effects on the energy signature of water supply infrastructure were found to be just as important as that of the fundamental processes for each option. Under historical (baseline) conditions, many option portfolios were capable of securing surface reservoir levels with a net neutral or negative effect on emissions and a benefit for renewable energy utilization. Under climate change augmented conditions, however, careful selection of the water supply option portfolio was required to prevent imposing major emissions increases for the system. Overall, this analysis provided quantitative insight into the tradeoffs associated with choosing different pathways for securing California's water supply.

  10. SOURCE APPORTIONMENT OF PM 2.5 AND CARBON IN SEATTLE USING CHEMICAL MASS BALANCE AND POSITIVE MATRIX FACTORIZATION

    Science.gov (United States)

    Three years of PM2.5 speciated data were collected and chemically analyzed using the IMPROVE protocol at the Beacon Hill site in Seattle. The data were analyzed by the Chemical Mass Balance Version 8 (CMB8) and Positive Matrix Factorization (PMF) source apportionment models. T...

  11. Disturbance and the carbon balance of US forests: A quantitative review of impacts from harvests, fires, insects, and droughts

    Science.gov (United States)

    Williams, Christopher A.; Gu, Huan; MacLean, Richard; Masek, Jeffrey G.; Collatz, G. James

    2016-08-01

    Disturbances are a major determinant of forest carbon stocks and uptake. They generally reduce land carbon stocks but also initiate a regrowth legacy that contributes substantially to the contemporary rate of carbon stock increase in US forestlands. As managers and policy makers increasingly look to forests for climate protection and mitigation, and because of increasing concern about changes in disturbance intensity and frequency, there is a need for synthesis and integration of current understanding about the role of disturbances and other processes in governing forest carbon cycle dynamics, and the likely future of this and other sinks for atmospheric carbon. This paper aims to address that need by providing a quantitative review of the distribution, extent and carbon impacts of the major disturbances active in the US. We also review recent trends in disturbances, climate, and other global environmental changes and consider their individual and collective contributions to the US carbon budget now and in the likely future. Lastly, we identify some key challenges and opportunities for future research needed to improve current understanding, advance predictive capabilities, and inform forest management in the face of these pressures. Harvest is found to be the most extensive disturbance both in terms of area and carbon impacts, followed by fire, windthrow and bark beetles, and lastly droughts. Collectively these lead to the gross loss of about 200 Tg C y- 1 in live biomass annually across the conterminous US. At the same time, the net change in forest carbon stocks is positive (190 Tg C y- 1), indicating not only forest resilience but also an apparently large response to growth enhancements such as fertilization by CO2 and nitrogen. Uncertainty about disturbance legacies, disturbance interactions, likely trends, and global change factors make the future of the US forest carbon sink unclear. While there is scope for management to enhance carbon sinks in US forests

  12. Components of near-surface energy balance derived from satellite soundings – Part 2: Latent heat flux

    Directory of Open Access Journals (Sweden)

    K. Mallick

    2014-06-01

    Full Text Available This paper introduces a relatively simple method for recovering global fields of latent heat flux. The method focuses on specifying Bowen ratio estimates through exploiting air temperature and vapour pressure measurements obtained from infra-red soundings of the AIRS (Atmospheric Infrared Sounder sensor onboard the NASA-Aqua platform. Through combining these Bowen ratio retrievals with satellite surface net available energy data we have specified estimates of global surface latent heat flux at the 1° by 1° scale. These estimates were evaluated against data from 30 terrestrial tower flux sites covering a broad spectrum of biomes. Taking monthly average 13:30 h data for 2003, this revealed a relatively good agreement between the satellite and tower measurements of latent heat flux, with a pooled root mean square deviation of 79 W m−2, and no significant bias. However, this success partly arose as a product of the under specification of the AIRS Bowen ratio compensating for the under specification of the AIRS net available energy.

  13. Organic Acids: The Pools of Fixed Carbon Involved in Redox Regulation and Energy Balance in Higher Plants

    OpenAIRE

    Abir U Igamberdiev; Eprintsev, Alexander T.

    2016-01-01

    Organic acids are synthesized in plants as a result of the incomplete oxidation of photosynthetic products and represent the stored pools of fixed carbon accumulated due to different transient times of conversion of carbon compounds in metabolic pathways. When redox level in the cell increases, e.g., in conditions of active photosynthesis, the tricarboxylic acid (TCA) cycle in mitochondria is transformed to a partial cycle supplying citrate for the synthesis of 2-oxoglutarate and glutamate (c...

  14. The greenhouse gas balance of a drained fen peatland is mainly controlled by land-use rather than soil organic carbon content

    Directory of Open Access Journals (Sweden)

    T. Eickenscheidt

    2015-04-01

    Full Text Available Drained organic soils are considered as hotspots for greenhouse gas (GHG emissions. Particularly arable lands and intensively used grasslands have been regarded as the main producers of carbon dioxide (CO2 and nitrous oxide (N2O. However, GHG balances of former peatlands and associated organic soils not considered as peatland according to the definition of the Intergovernmental Panel on Climate Change (IPCC have not been investigated so far. Therefore, our study addressed the question to what extent the soil organic carbon (SOC content affects the GHG release of drained organic soils under two different land-use types (arable land and intensively used grassland. Both land-use types were established on a mollic Gleysol (named Cmedium as well as on a sapric Histosol (named Chigh. The two soil types significantly differed in their SOC contents in the topsoil (Cmedium: 9.4–10.9% SOC; Chigh: 16.1–17.2% SOC. We determined GHG fluxes (CO2, N2O and methane (CH4 over a period of 2 years. The daily and annual net ecosystem exchange (NEE of CO2 was determined with the closed dynamic chamber technique and by modeling the ecosystem respiration (RECO and the gross primary production (GPP. N2O and CH4 were determined by the close chamber technique. Estimated NEE of CO2 significantly differed between the two land-use types with lower NEE values (−6 to 1707 g CO2–C m−2 yr−1 at the arable sites and higher values (1354 to 1823 g CO2–C m−2 yr−1 at the grassland sites. No effect on NEE was found regarding the SOC content. Significantly higher annual N2O exchange rates were observed at the arable sites (0.23–0.86 g N m−2 yr−1 compared to the grassland sites (0.12–0.31 g N m−2 yr−1. Furthermore, N2O fluxes from the Chigh sites significantly exceeded those of the Cmedium sites. CH4 fluxes were found to be close to zero at all plots. Estimated global warming potential, calculated for a time horizon of 100 years (GWP100 revealed a very high

  15. HyFlux - Part II: Subsurface sequestration of methane-derived carbon in gas-hydrate- bearing marine sediments

    Science.gov (United States)

    Naehr, T. H.; Asper, V. L.; Garcia, O.; Kastner, M.; Leifer, I.; MacDonald, I. R.; Solomon, E. A.; Yvon-Lewis, S.; Zimmer, B.

    2008-12-01

    The recently funded DOE/NETL study "HyFlux: Remote sensing and sea-truth measurements of methane flux to the atmosphere" (see MacDonald et al.: HyFlux - Part I) will combine sea surface, water column and shallow subsurface observations to improve our estimates of methane flux from submarine seeps and associated gas hydrate deposits to the water column and atmosphere along the Gulf of Mexico continental margin and other selected areas world-wide. As methane-rich fluids rise towards the sediment-water interface, they will interact with sulfate-rich pore fluids derived from overlying bottom water, which results in the formation of an important biogeochemical redox boundary, the so-called sulfate-methane interface, or SMI. Both methane and sulfate are consumed within the SMI and dissolved inorganic carbon, mostly bicarbonate (HCO3-) and hydrogen sulfide are produced, stimulating authigenic carbonate precipitation at and immediately below the SMI. Accordingly, the formation of authigenic carbonates in methane- and gas-hydrate-rich sediments will sequester a portion of the methane-derived carbon. To date, however, little is known about the quantitative aspects of these reactions. Rates of DIC production are not well constrained, but recent biogeochemical models indicate that CaCO3 precipitation rates may be as high as 120 μmol cm-2a-1. Therefore, AOM-driven carbonate precipitation must be considered when assessing the impact of gas-hydrate-derived methane on the global carbon cycle. As part of HyFlux, we will conduct pore water analyses (DOC, DIC, CH4, δ13CDIC, δ13CDOC, δ13CCH4, δ18O, and δD isotope ratios) to evaluate the importance of authigenic carbonate precipitation as a sequestration mechanism for methane- derived carbon. In addition, sediment and seafloor carbonate samples will be analyzed for bulk sedimentary carbonate (δ13C and δ18O) and bulk sedimentary organic matter (δ13C and δ15N), as well as sulfur, bulk mineralogy, texture and morphological

  16. DRUM: a new framework for metabolic modeling under non-balanced growth. Application to the carbon metabolism of unicellular microalgae.

    Directory of Open Access Journals (Sweden)

    Caroline Baroukh

    Full Text Available Metabolic modeling is a powerful tool to understand, predict and optimize bioprocesses, particularly when they imply intracellular molecules of interest. Unfortunately, the use of metabolic models for time varying metabolic fluxes is hampered by the lack of experimental data required to define and calibrate the kinetic reaction rates of the metabolic pathways. For this reason, metabolic models are often used under the balanced growth hypothesis. However, for some processes such as the photoautotrophic metabolism of microalgae, the balanced-growth assumption appears to be unreasonable because of the synchronization of their circadian cycle on the daily light. Yet, understanding microalgae metabolism is necessary to optimize the production yield of bioprocesses based on this microorganism, as for example production of third-generation biofuels. In this paper, we propose DRUM, a new dynamic metabolic modeling framework that handles the non-balanced growth condition and hence accumulation of intracellular metabolites. The first stage of the approach consists in splitting the metabolic network into sub-networks describing reactions which are spatially close, and which are assumed to satisfy balanced growth condition. The left metabolites interconnecting the sub-networks behave dynamically. Then, thanks to Elementary Flux Mode analysis, each sub-network is reduced to macroscopic reactions, for which simple kinetics are assumed. Finally, an Ordinary Differential Equation system is obtained to describe substrate consumption, biomass production, products excretion and accumulation of some internal metabolites. DRUM was applied to the accumulation of lipids and carbohydrates of the microalgae Tisochrysis lutea under day/night cycles. The resulting model describes accurately experimental data obtained in day/night conditions. It efficiently predicts the accumulation and consumption of lipids and carbohydrates.

  17. Balance Problems

    Science.gov (United States)

    ... you are having balance problems, see your doctor. Balance disorders can be signs of other health problems, such ... cases, treating the illness that is causing the disorder will help with the balance problem. Exercises, a change in diet, and some ...

  18. Soil climate and decomposer activity in Sub-Saharan Africa estimated from standard weather station data: a simple climate index for soil carbon balance calculations.

    Science.gov (United States)

    Andrén, Olof; Kihara, Job; Bationo, André; Vanlauwe, Bernard; Kätterer, Thomas

    2007-07-01

    Soil biological activity was calculated on a daily basis, using standard meteorological data from African weather stations, a simple soil water model, and commonly used assumptions regarding the relations between temperature, soil water content, and biological activity. The activity factor r(e_clim) is calculated from daily soil moisture and temperature, thereby taking the daily interaction between temperature and moisture into account. Annual mean r(e_clim) was normalized to 1 in Central Sweden (clay loam soil, no crop), where the original calibration took place. Since soils vary in water storage capacity and plant cover will affect transpiration, we used this soil under no crop for all sites, thereby only including climate differences. The Swedish r(e_clim) value, 1, corresponds to ca. 50% annual mass loss of, e.g., cereal straw incorporated into the topsoil. African mean annual r(e_clim) values varied between 1.1 at a hot and dry site (Faya, Chad) and 4.7 at a warm and moist site (Brazzaville, Congo). Sites in Kenya ranged between r(e_clim) = 2.1 at high altitude (Matanya) and 4.1 in western Kenya (Ahero). This means that 4.1 times the Swedish C input to soil is necessary to maintain Swedish soil carbon levels in Ahero, if soil type and management are equal. Diagrams showing daily r(e_clim) dynamics are presented for all sites, and differences in within-year dynamics are discussed. A model experiment indicated that a Swedish soil in balance with respect to soil carbon would lose 41% of its soil carbon during 30 y, if moved to Ahero, Kenya. If the soil was in balance in Ahero with respect to soil carbon, and then moved to Sweden, soil carbon mass would increase by 64% in 30 y. The validity of the methodology and results is discussed, and r(e_clim) is compared with other climate indices. A simple method to produce a rough estimate of r(e_clim) is suggested.

  19. Carbon balance in conterminous U.S. forests based on historic changes in climate, atmospheric composition, and disturbances

    Science.gov (United States)

    Zhang, F.; Chen, J.; Ju, W.; Shen, S.; Pan, Y.; Birdsey, R.; He, L.

    2010-12-01

    Forest ecosystems are the dominant contributors to the carbon sink in terrestrial ecosystems. Although many studies have already explored the effects of non-disturbance factors such as climate and atmospheric composition on the terrestrial carbon cycle, few studies have systematically considered the impact of disturbance on the forest carbon cycle at regional scale, mostly because of the lack of spatially and temporally explicit disturbance data. In this study, we show, for the first time, the spatio-temporal distribution of the carbon sink in conterminous U.S. forests from 1901 to 2006 modeled with the consideration of both disturbance and non-disturbance effects using the Integrated Terrestrial Ecosystem Carbon Model (InTEC). The application of this model is possible owing to the recently available national forest age data in 2000. Our results show that the annual net primary productivity of conterminous U.S. forests increased from 1476 Tg C yr-1 in the early 20th century to 1892 Tg C yr-1 in the early 21st century, whereas the net biome productivity increased from -32.9 Tg C yr-1 to 422.5 Tg C yr-1 in the same period. The overall results indicate that forest sink extended from North regions to South and Southeast regions and the maximum sink occurred in the Kentucky and Tennesee states after 1990. Fig. 1. (a-c) Carbon (C) dynamics of the conterminous U.S. forests over last 106 years from 1901 to 2006 (a-c); (d-f) Spatial distribution of carbon sources/sinks in the forest ecosystems of the conterminous U.S. in the 1980s, 1990s and 2000s. Table 1 Changes of carbon storages of forest ecosystem in different regions of the conterminous U.S. over last 106 years from 1901 to 2006 (Unit: Tg C yr-1). (1) Northeast (NE); (2) Northern Lake (NL); (3) North Plain (NP); (4) Pacific Northwest (PN); (5) Pacific Southwest (PS); (6) Rocky Mountain North (RMN); (7) Rocky Mountain South (RMS); (8) South Central (SC); (9) Southeast (SE).

  20. The dynamic balance of the children with cerebral palsy and typical developing during gait Part II: Instantaneous velocity and acceleration of COM and COP and their relationship.

    Science.gov (United States)

    Hsue, Bih-Jen; Miller, Freeman; Su, Fong-Chin

    2009-04-01

    As a companion research subsequent to analyzing displacement of center of mass (COM) and center of pressure (COP) in Part I, the purposes of this study were to quantify dynamic stability using magnitudes and patterns of instantaneous velocity and acceleration of COM and COP of the children with cerebral palsy (CP) during walking, and compare the data with those of the typically developing (TD) children. The instantaneous velocity and acceleration of COM and COP were acquired by calculating the first and second derivatives of displacement data presented in Part I. Velocity and acceleration of COM and COP were normalized by each participant's leg length to eliminate the influence of individual's stature. The results indicate that the preferred walking speed is significantly higher in TD groups than hemiplegic group (Hemi) and diplegic group (Di). The peak values of instantaneous velocity and acceleration of COM in vertical, medio-lateral (ML) and antero-posterior (AP) directions and velocity and acceleration of COP in ML direction were significantly higher in Di group than TD group. Both CP groups showed great variability in COM and COP parameters. Therefore, although Di group demonstrated higher peak values than Hemi group, the only significant difference between two groups was instantaneous COP velocity in ML direction. The findings of this study suggest that this assessment may be of value for research or clinical evaluation of dynamic balance dysfunction during walking and provide comparisons and insights for specific treatments or surgical interventions for the children with CP.

  1. The Stable Level of Glutamine synthetase 2 Plays an Important Role in Rice Growth and in Carbon-Nitrogen Metabolic Balance.

    Science.gov (United States)

    Bao, Aili; Zhao, Zhuqing; Ding, Guangda; Shi, Lei; Xu, Fangsen; Cai, Hongmei

    2015-06-04

    Glutamine synthetase 2 (GS2) is a key enzyme involved in the ammonium metabolism in plant leaves. In our previous study, we obtained GS2-cosuppressed plants, which displayed a normal growth phenotype at the seedling stage, while at the tillering stage they showed a chlorosis phenotype. In this study, to investigate the chlorosis mechanism, we systematically analyzed the plant growth, carbon-nitrogen metabolism and gene expressions between the GS2-cosuppressed rice and wild-type plants. The results revealed that the GS2-cosuppressed plants exhibited a poor plant growth phenotype and a poor nitrogen transport ability, which led to nitrogen accumulation and a decline in the carbon/nitrogen ratio in the stems. Interestingly, there was a higher concentration of soluble proteins and a lower concentration of carbohydrates in the GS2-cosuppressed plants at the seedling stage, while a contrasting result was displayed at the tillering stage. The analysis of the metabolic profile showed a significant increase of sugars and organic acids. Additionally, gene expression patterns were different in root and leaf of GS2-cosuppressed plants between the seedling and tillering stage. These results indicated the important role of a stable level of GS2 transcription during normal rice development and the importance of the carbon-nitrogen metabolic balance in rice growth.

  2. The OSU1/QUA2/TSD2-encoded putative methyltransferase is a critical modulator of carbon and nitrogen nutrient balance response in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Peng Gao

    Full Text Available The balance between carbon (C and nitrogen (N nutrients must be tightly coordinated so that cells can optimize their opportunity for metabolism, growth and development. However, the C and N nutrient balance perception and signaling mechanism remains poorly understood. Here, we report the isolation and characterization of two allelic oversensitive to sugar 1 mutants (osu1-1, osu1-2 in Arabidopsis thaliana. Using the cotyledon anthocyanin accumulation and root growth inhibition assays, we show that the osu1 mutants are more sensitive than wild-type to both of the imbalanced C/N conditions, high C/low N and low C/high N. However, under the balanced C/N conditions (low C/low N or high C/high N, the osu1 mutants have similar anthocyanin levels and root lengths as wild-type. Consistently, the genes encoding two MYB transcription factors (MYB75 and MYB90 and an Asn synthetase isoform (ASN1 are strongly up-regulated by the OSU1 mutation in response to high C/low N and low C/high N, respectively. Furthermore, the enhanced sensitivity of osu1-1 to high C/low N with respect to anthocyanin accumulation but not root growth inhibition can be suppressed by co-suppression of MYB75, indicating that MYB75 acts downstream of OSU1 in the high C/low N imbalance response. Map-based cloning reveals that OSU1 encodes a member of a large family of putative methyltransferases and is allelic to the recently reported QUA2/TSD2 locus identified in genetic screens for cell-adhesion-defective mutants. Accumulation of OSU1/QUA2/TSD2 transcript was not regulated by C and N balance, but the OSU1 promoter was slightly more active in the vascular system. Taken together, our results show that the OSU1/QUA2/TSD2-encoded putative methyltransferase is required for normal C/N nutrient balance response in plants.

  3. Emission Inventories of Carbon-containing Greenhouse Gases in and Technological Measures for Their Abatement

    Institute of Scientific and Technical Information of China (English)

    Zhuang Yahui; Zhang Hongxun; Wang Xiaoke; Li Changsheng

    2004-01-01

    The report summarizes surveys on carbon inventories and initiatives on sustainable carbon cycling taken by the Research Center for EcoEnvironmental Sciences, where the authors work/worked. The first part of the report, which appeared in the preceding issue of this journal, deals with the concept of sustainable carbon cycling, the historic evolution of carbon cycling processes in China, carbon pool enhancement, value addition,carbon sequestration and carbon balance. This very paper, as the second part of the report, covers the results of carbon dynamics modeling, emission inventories of various carbon-containing greenhouse gases and their potential abatement measures.

  4. Thermal acclimation of leaf respiration of tropical trees and lianas: response to experimental canopy warming, and consequences for tropical forest carbon balance.

    Science.gov (United States)

    Slot, Martijn; Rey-Sánchez, Camilo; Gerber, Stefan; Lichstein, Jeremy W; Winter, Klaus; Kitajima, Kaoru

    2014-09-01

    Climate warming is expected to increase respiration rates of tropical forest trees and lianas, which may negatively affect the carbon balance of tropical forests. Thermal acclimation could mitigate the expected respiration increase, but the thermal acclimation potential of tropical forests remains largely unknown. In a tropical forest in Panama, we experimentally increased nighttime temperatures of upper canopy leaves of three tree and two liana species by on average 3 °C for 1 week, and quantified temperature responses of leaf dark respiration. Respiration at 25 °C (R25 ) decreased with increasing leaf temperature, but acclimation did not result in perfect homeostasis of respiration across temperatures. In contrast, Q10 of treatment and control leaves exhibited similarly high values (range 2.5-3.0) without evidence of acclimation. The decrease in R25 was not caused by respiratory substrate depletion, as warming did not reduce leaf carbohydrate concentration. To evaluate the wider implications of our experimental results, we simulated the carbon cycle of tropical latitudes (24°S-24°N) from 2000 to 2100 using a dynamic global vegetation model (LM3VN) modified to account for acclimation. Acclimation reduced the degree to which respiration increases with climate warming in the model relative to a no-acclimation scenario, leading to 21% greater increase in net primary productivity and 18% greater increase in biomass carbon storage over the 21st century. We conclude that leaf respiration of tropical forest plants can acclimate to nighttime warming, thereby reducing the magnitude of the positive feedback between climate change and the carbon cycle.

  5. Effect of climate change, CO2 trends, nitrogen addition, and land-cover and management intensity changes on the carbon balance of European grasslands.

    Science.gov (United States)

    Chang, Jinfeng; Ciais, Philippe; Viovy, Nicolas; Vuichard, Nicolas; Herrero, Mario; Havlík, Petr; Wang, Xuhui; Sultan, Benjamin; Soussana, Jean-François

    2016-01-01

    Several lines of evidence point to European managed grassland ecosystems being a sink of carbon. In this study, we apply ORCHIDEE-GM a process-based carbon cycle model that describes specific management practices of pastures and the dynamics of carbon cycling in response to changes in climatic and biogeochemical drivers. The model is used to simulate changes in the carbon balance [i.e., net biome production (NBP)] of European grasslands over 1991-2010 on a 25 km × 25 km grid. The modeled average trend in NBP is 1.8-2.0 g C m(-2)  yr(-2) during the past two decades. Attribution of this trend suggests management intensity as the dominant driver explaining NBP trends in the model (36-43% of the trend due to all drivers). A major change in grassland management intensity has occurred across Europe resulting from reduced livestock numbers. This change has 'inadvertently' enhanced soil C sequestration and reduced N2 O and CH4 emissions by 1.2-1.5 Gt CO2 -equivalent, offsetting more than 7% of greenhouse gas emissions in the whole European agricultural sector during the period 1991-2010. Land-cover change, climate change and rising CO2 also make positive and moderate contributions to the NBP trend (between 24% and 31% of the trend due to all drivers). Changes in nitrogen addition (including fertilization and atmospheric deposition) are found to have only marginal net effect on NBP trends. However, this may not reflect reality because our model has only a very simple parameterization of nitrogen effects on photosynthesis. The sum of NBP trends from each driver is larger than the trend obtained when all drivers are varied together, leaving a residual - nonattributed - term (22-26% of the trend due to all drivers) indicating negative interactions between drivers.

  6. Effect of crop residue harvest on long-term crop yield, soil erosion, and carbon balance: tradeoffs for a sustainable bioenergy feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Gregg, Jay S.; Izaurralde, Roberto C.

    2010-08-26

    Agricultural residues are a potential feedstock for bioenergy production, if residue harvest can be done sustainably. The relationship between crop residue harvest, soil erosion, crop yield and carbon balance was modeled with the Erosion Productivity Impact Calculator/ Environment Policy Integrated Climate (EPIC) using a factorial design. Four crop rotations (winter wheat [Triticum aestivum (L.)] – sunflower [Helianthus annuus]; spring wheat [Triticum aestivum (L.)] – canola [Brassica napus]; corn [Zea mays L.] – soybean [Glycine max (L.) Merr.]; and cotton [Gossypium hirsutum] – peanut [Arachis hypogaea]) were simulated at four US locations each, under different topographies (0-10% slope), and management practices [crop residue removal rates (0-75%), conservation practices (no till, contour cropping, strip cropping, terracing)].

  7. Deviation of Carbon Dioxide-Water Gas-Liquid Balance from Thermodynamic Equilibrium in Turbulence I:Experiment and Correlation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhenzhen; QIAN Zhi; XU Lianbin; WU Caiyan; GUO Kai

    2013-01-01

    The carbon dioxide-water system was used to investigate the flowing gas-liquid metastable state.The experiment was carried out in a constant volume vessel with a horizontal circulation pipe and a peristaltic pump forced CO2 saturated water to flow.The temperature and pressure were recorded.The results showed that some CO2 escaped from the water in the flow process and the pressure increased,indicating that the gas-liquid equilibrium was broken.The amount of escaped CO2 varied with flow speed and reached a limit in a few minutes,entitled dynamic equilibrium.Temperature and liquid movement played the same important role in breaking the phase equilibrium.Under the experimental conditions,the ratio of the excessive carbon dioxide in the gas phase to its thermodynamic equilibrium amount in the liquid could achieve 15%.

  8. Carbon balance impacts of land use changes related to the life cycle of Malaysian palm oil-derived biodiesel

    DEFF Research Database (Denmark)

    Hansen, Sune Balle; Olsen, Stig Irving; Ujang, Zaini

    2014-01-01

    The area of oil palm plantations in Malaysia is expanding by approximately 0.14 million hectare per year, and with the increasing demand for palm oil worldwide, there is no sign of the expansions slowing down. This study aims to identify the greenhouse gas emissions associated with land conversion...... to oil palm, in a life cycle perspective.LCA methodology is applied to existing land use change data. The assessment includes the issue of temporary carbon storage in the plantations. Through quantification of emissions from state forest reserve and rubber plantation conversions, the average Malaysian...... palm oil-related land use changes are calculated.The results show that there are high emissions associated with the conversion of Malaysian state forest reserve to oil palm, whereas the conversion of rubber leaves a less significant carbon debt when indirect land use change is not included. Looking...

  9. The Elum Project: A Network of UK Sites to Understand Land-Use Transitions to Bioenergy and Their Implications for Greenhouse Gas Balance and Carbon Cycling

    Science.gov (United States)

    Harris, Z. M.; Alberti, G.; Bottoms, E.; Rowe, R.; Parmar, K.; Marshall, R.; Elias, D.; Smith, P.; Dondini, M.; Pogson, M.; Richards, M.; Finch, J.; Ineson, P.; Keane, B.; Perks, M.; Wilkinson, M.; Yamulki, S.; Donnison, I.; Farrar, K.; Massey, A.; McCalmont, J.; Drewer, J.; Sohi, S.; McNamara, N.; Taylor, G.

    2014-12-01

    Rising anthropogenic greenhouse gas (GHG) emissions coupled with an increasing need to address energy security are resulting in the development of cleaner, more sustainable alternatives to traditional fossil fuel sources. Bioenergy crops have been proposed to be able to mitigate the effects of climate change as well as provide increased energy security. The aim of this project is to assess the impact of land conversion to second generation non-food bioenergy crops on GHG balance for several land use transitions, including from arable, grassland and forest. A network of 6 sites was established across the UK to assess the processes underpinning GHG balance and to provide input data to a model being used to assess the sustainability of different land use transitions. Monthly analysis of soil GHGs shows that carbon dioxide contributes most to the global warming potential of these bioenergy crops, irrespective of transition. Nitrous oxide emissions were low for all crops except arable cropping and methane emissions were very low for all sites. Nearly all sites have shown a significant decrease in CO2 flux from the control land use. Eddy flux approaches, coupled with soil assessments show that for the transition from grassland to SRC willow there is a significant reduction in GHG emissions from soil and a negative net ecosystem exchange due to increased GPP and ecosystem respiration. These results suggest for this land use transition to bioenergy in a UK specific context, there may be a net benefit for ecosystem GHG exchange of transition to bioenergy Finally we are developing a meta-modelling tool to allow land use managers to make location-specific, informed decisions about land use change to bioenergy. This work is based on the Ecosystem Land Use Modelling & Soil Carbon GHG Flux Trial (ELUM) project, which was commissioned and funded by the Energy Technologies Institute (ETI). This project is co-ordinated by the Centre for Ecology & Hydrology (www.elum.ac.uk).

  10. The 'Bilan Carbone'. Overview of a carbon balance method allowing to evaluate company's exposure to fossil energy costs fluctuation

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, Sylvie; Galio, Pierre [ADEME - French Agency for Environment and Energy Management, Angers (France)

    2007-07-01

    90 % of the carbon dioxide emitted comes from the combustion of fossil energies (petroleum products, coal and natural gas) and is therefore directly related to energy consumption. The European Union has committed to reducing its greenhouse gas emissions by 8 % by 2008-2012 in relation to levels recorded in 1990 (Kyoto Protocol). This commitment involves for the European Union an ambitious policy aiming at making industries more energy efficient with three main goals:cutting the high cost of energy; reducing fossils energies addiction; launching an emissions reduction process. ADEME (French Agency for Environment and Energy Management) developed a simple method which is an effective solution for ranking emissions by source and for launching a dynamic emissions reduction process: the Bilan Carbone Method.Bilan Carbone is both a tool and a methodology. The main component of the tool is a ready-to-use Excel spreadsheet that calculates the emissions caused by all the processes necessary for the existence of a given activity. Space heating, combustion for manufacturing processes, but also freight shipments, passengers travel, production of raw materials used, waste treatment - To take these items into account, simply fill in the spreadsheet with energy consumption figures, kilometers travelled, quantities of materials purchased, etc. For each source of CO{sub 2} or other greenhouse gases, theses data are then converted by the spreadsheet into the amount of carbon emitted, using fully documented emissions factors. The general spirit of the Bilan Carbone method is to provide the broadest possible panorama of emissions that are linked to processes used by a company or an organization. This is also the only approach that is pertinent for looking forward and anticipating the effect of possible trends, for instance a significant rise in the market price of fossil energy.In practice, the accuracy of the results will depend to a large extent on the amount of time spent

  11. Coupled Climate-Economy-Biosphere (CoCEB) model - Part 1: Abatement share and investment in low-carbon technologies

    Science.gov (United States)

    Ogutu, K. B. Z.; D'Andrea, F.; Ghil, M.; Nyandwi, C.; Manene, M. M.; Muthama, J. N.

    2015-04-01

    The Coupled Climate-Economy-Biosphere (CoCEB) model described herein takes an integrated assessment approach to simulating global change. By using an endogenous economic growth module with physical and human capital accumulation, this paper considers the sustainability of economic growth, as economic activity intensifies greenhouse gas emissions that in turn cause economic damage due to climate change. Different types of fossil fuels and different technologies produce different volumes of carbon dioxide in combustion. The shares of different fuels and their future evolution are not known. We assume that the dynamics of hydrocarbon-based energy share and their replacement with renewable energy sources in the global energy balance can be modeled into the 21st century by use of logistic functions. Various climate change mitigation policy measures are considered. While many integrated assessment models treat abatement costs merely as an unproductive loss of income, we consider abatement activities also as an investment in overall energy efficiency of the economy and decrease of overall carbon intensity of the energy system. The paper shows that these efforts help to reduce the volume of industrial carbon dioxide emissions, lower temperature deviations, and lead to positive effects in economic growth.

  12. Strong magnetism observed in carbon nanoparticles produced by the laser vaporization of a carbon pellet in hydrogen-containing Ar balance gas.

    Science.gov (United States)

    Asano, Hirohito; Muraki, Susumu; Endo, Hiroki; Bandow, Shunji; Iijima, Sumio

    2010-08-25

    Nanometer-scale carbon particles driven by the pulsed-laser vaporization of pelletized pure carbon powder at 1000 °C in a hydrogen-containing environment show anomalous magnetism like a superparamagnet, while the sample prepared in 100% of Ar does not show such magnetism. The observed magnetism was unchanged over months in the ambient. The structure of this nanomaterial resembles the foam of a laundry detergent and transmission electron microscopy indicates a clear corrugated line contrast. On the other hand, a sample without strong magnetism does not give such an image contrast. The x-ray diffraction pattern coincides with that of graphite and no other peak is detected. Thermogravimetry indicates that all samples completely burn out up to approx. 820 °C and no material remains after combustion, indicating that the sample does not contain impurity metals. Magnetization is easily saturated by ∼10,000 G at 280 K with no hysteresis, but the hysteresis appears at 4.2 K. This phenomenon is explained by introducing a crystalline anisotropy which restricts the motion of the magnetic moment and stabilizes the remnant magnetization at zero magnetic field. Magnitudes of the saturation magnetization are in the range of 1-5 emu G g(-1) at 4.2 K, which correspond to 0.002-0.01 Bohr magneton per carbon atom. This concentration may be increased by ten times or more, because only about 4-10% of particles have a magnetic domain in the present samples.

  13. Quantifying the Carbon Balance of Forest Restoration and Wildfire under Projected Climate in the Fire-Prone Southwestern US

    Science.gov (United States)

    2017-01-01

    Climate projections for the southwestern US suggest a warmer, drier future and have the potential to impact forest carbon (C) sequestration and post-fire C recovery. Restoring forest structure and surface fire regimes initially decreases total ecosystem carbon (TEC), but can stabilize the remaining C by moderating wildfire behavior. Previous research has demonstrated that fire maintained forests can store more C over time than fire suppressed forests in the presence of wildfire. However, because the climate future is uncertain, I sought to determine the efficacy of forest management to moderate fire behavior and its effect on forest C dynamics under current and projected climate. I used the LANDIS-II model to simulate carbon dynamics under early (2010–2019), mid (2050–2059), and late (2090–2099) century climate projections for a ponderosa pine (Pinus ponderosa) dominated landscape in northern Arizona. I ran 100-year simulations with two different treatments (control, thin and burn) and a 1 in 50 chance of wildfire occurring. I found that control TEC had a consistent decline throughout the simulation period, regardless of climate. Thin and burn TEC increased following treatment implementation and showed more differentiation than the control in response to climate, with late-century climate having the lowest TEC. Treatment efficacy, as measured by mean fire severity, was not impacted by climate. Fire effects were evident in the cumulative net ecosystem exchange (NEE) for the different treatments. Over the simulation period, 32.8–48.9% of the control landscape was either C neutral or a C source to the atmosphere and greater than 90% of the thin and burn landscape was a moderate C sink. These results suggest that in southwestern ponderosa pine, restoring forest structure and surface fire regimes provides a reasonable hedge against the uncertainty of future climate change for maintaining the forest C sink. PMID:28046079

  14. Carbon dioxide stripping in aquaculture -- part II: development of gas transfer models

    Science.gov (United States)

    Colt, John; Watten, Barnaby; Pfeiffer, Tim

    2012-01-01

    The basic mass transfer equation for gases such as oxygen and carbon dioxide can be derived from integration of the driving force equation. Because of the physical characteristics of the gas transfer processes, slightly different models are used for aerators tested under the non steady-state procedures, than for packed columns, or weirs. It is suggested that the standard condition for carbon dioxide should be 20 °C, 1 atm, CCO2=20 mg/kg, and XCO2=0.000285. The selection of the standard condition for carbon dioxide based on a fixed mole fraction ensures that standardized carbon dioxide transfer rates will be comparable even though the value of C*CO2 in the atmosphere is increasing with time. The computation of mass transfer for carbon dioxide is complicated by the impact of water depth and gas phase enrichment on the saturation concentration within the unit, although the importance of either factor depends strongly on the specific type of aerator. For some types of aerators, the most accurate gas phase model remains to be determined for carbon dioxide. The assumption that carbon dioxide can be treated as a non-reactive gas in packed columns may apply for cold acidic waters but not for warm alkaline waters.

  15. Improved constraints on in situ rates and on quantification of complete chloroethene degradation from stable carbon isotope mass balances in groundwater plumes

    Science.gov (United States)

    Höhener, Patrick; Elsner, Martin; Eisenmann, Heinrich; Atteia, Olivier

    2015-11-01

    Spills of chloroethenes (CEs) at industrial and urban sites can create groundwater plumes in which tetrachloro- and trichloroethene sequentially degrade to dichloroethenes, vinyl chloride (VC) and ethene, or ethane under reducing conditions. For detoxification, degradation must go beyond VC. Assessments based on ethene and ethane, however, are difficult because these products are volatile, may stem from alternative sources, can be further transformed and are not always monitored. To alternatively quantify degradation beyond VC, stable carbon isotope mass balances have been proposed where concentration-weighted CE isotope ratios are summed up and compared to the original source isotope ratio. Reported assessments, however, have provided not satisfactorily quantified results entailing greatly differing upper and lower estimates. This work proposes an integrative approach to better constrain the extent of total chloroethene degradation in groundwater samples. It is based on fitting of measured concentration and compound-specific stable carbon isotope data to an analytical reactive transport equation simulating steady-state plumes in two dimensions using an EXCEL spreadsheet. The fitting also yields estimates of degradation rates, of source width and of dispersivities. The approach is validated using two synthetic benchmark cases where the true extent of degradation is well known, and using data from two real field cases from literature.

  16. Evolution of Early Cretaceous paleotemperatures: A balance between global carbon burial rates and large igneous provinces activity

    Science.gov (United States)

    Bodin, Stephane; Meissner, Philipp; Janssen, Nico; Steuber, Thomas; Mutterlose, Jörg

    2015-04-01

    The lack of a high-resolution, long-term Early Cretaceous paleotemperature record hampers a full-scale comprehension, as well as a more holistic approach, to Early Cretaceous climate changes. Here we present an extended compilation of belemnite-based oxygen, carbon and strontium isotope records covering the late Berriasian - middle Albian from the Vocontian Basin (SE France). Integrated with paleontological and sedimentological evidences, this dataset clearly demonstrates that three intervals of cold climatic conditions have taken place during the Early Cretaceous greenhouse world. More specifically, these have taken place during (1) the late Valanginian-earliest Hauterivian, (2) the late early Aptian and (3) the latest Aptian - earliest Albian. Each of these intervals is associated with high amplitude sea-level fluctuations, pointing at transient installations of polar ice caps. As evidenced by carbon isotope positive excursions, each cold episode is associated with enhanced burial of organic matter on a global scale. Moreover, there is a very good match between the timing and size of large igneous provinces eruptions and the amplitude of Early Cretaceous warming episodes. Altogether, these observations confirm the instrumental role of atmospheric CO2 variations in the making of Mesozoic climate change. On a long-term perspective, during the Early Cretaceous, the coupling of global paleotemperature and seawater strontium isotopic ratio is best explained by temperature-controlled changes of continental crust weathering rates.

  17. Weed-cover versus weed-removal management in olive orchards: influence on the carbon balance at the ecosystem scale

    Science.gov (United States)

    Chamizo, Sonia; Serrano-Ortiz, Penélope; Vicente-Vicente, José Luis; Sánchez-Cañete, Enrique P.; López-Ballesteros, Ana; Kowalski, Andrew S.

    2016-04-01

    Agriculture plays an important role in the C budget at the global scale. Traditional practices based on soil tillage and applying herbicides to remove weeds have caused damage to soils and led to important losses of soil organic C and increased CO2 emissions to the atmosphere. Changing trends from traditional agriculture to conservation agriculture practices may have an important role in both C and water budgets and the transformation of agriculture from C source to C sink. The objective of this study was to analyse the effect of two treatments, weed removal by herbicides versus weed cover conservation, on the C balance in an irrigated olive orchard in SE Spain. Measurements of CO2 exchange were made from October 2014 to September 2015 using two eddy covariance towers, one for each olive crop treatment. Results show that CO2 fluxes at the ecosystem scale were similar in the two treatments during initial conditions, prior to weed growth in the soils without herbicide application (October). During the first week, daily net ecosystem exchange (NEE) was close to zero in both treatments, with values ranging from 1.06 to -0.41 g C m-2 in the weed cover treatment, and from 0.76 to -0.69 g C m-2 in the weed removal treatment. As weed growth increased, higher net CO2 assimilation was found in the treatment with weed cover. In both treatments, maximum net CO2 assimilation was found in March, with a monthly NEE of -72 and -28 g C m-2 in the treatment with and without weed cover, respectively. In May, after the weeds were cut and left on the soil, a strong increase was observed in NEE in the treatment with weed cover due to decreased CO2 assimilation and increased respiration compared to the treatment without weed cover. Therefore, soil chamber measurements showed average respiration rates of 2.57 and 1.57 μmol m-2 s-2 in the weed cover and weed removal treatment, respectively. Finally, the highest monthly NEE was registered during July, with both treatments showing a similar

  18. Assessment of Human Lung Macrophages After Exposure to Multi-Walled Carbon Nanotubes. Part 1. Cytotoxicity

    Science.gov (United States)

    2011-01-01

    etc. although many other forms and structures such as carbon nanohorns, nanodiamonds , etc. exist. Due to the atomic arrangement of CNTs, they are...Developments in Chemistry, Physics, Materials Science and Device Applications , Elsevier, Amsterdam (2006). 2. B. Warheit, B. R. Laurence, K. L. Reed, D. H...Cytotoxicity and Genotoxicity of Carbon Nanomaterials in Safety of Nanoparticles: From Manu- facturing to Clinical Applications , edited by T. Webster

  19. CO{sub 2} enrichment and carbon partitioning to phenolics: do plant responses accord better with the protein competition or the growth differentiation balance models?

    Energy Technology Data Exchange (ETDEWEB)

    Mattson, W.J. [Forestry Sciences Lab., Rhinelander, WI (United States); Julkunen-Tiitto, R. [Univ. of Joensuu, Biology Dept., Joensuu (Finland); Herms, D.A. [Ohio State Univ., Dept. of Entmology, Wooster, OH (United States)

    2005-11-01

    Rising levels of atmospheric CO{sub 2} can alter plant growth and partitioning to secondary metabolites. The protein competition model (PCM) and the extended growth/differentiation balance model (GDB{sub e}) are similar but alternative models that address ontogenetic and environmental effects on whole-plant carbon partitioning to the phenylpropanoid biosynthetic pathway, making many divergentpredictins. To test the validity of the models, we compare plant responses to one key prediction: if CO{sub 2} enrichment simultaneously stimulates both photosynthesis and growth, then PCM predicts that partitioning to phenolic compounds will decline, whereas GDB{sub e} generally predicts the opposite. Elevated CO{sub 2} (at 548 ppm) increased the biomass growth (ca 23%) as well as the net photosynthesis (ca 13%) of 1-year-old potted paper birch, Betula papyrifera Marsch., in a free air carbon dioxide enrichment study (FACE) in northern Wisconsin. Concomitantly, elevated CO{sub 2} increased carbon partitioning to all measured classes of phenolics (Folin-Denis phenolics, HPLC low molecular weight phenolics (i.e. cinnamic acid derivatives, flavonol flycosides, and flavon-3-ols), condensed tannins, and acid-detergent lignin) in leaves. In stem tissues, tannins and lignin increased, but F-D phenolics did not. In root tissues, F-D phenolics, and tannins increased, but lignin did not. The data suggest that CO{sub 2} enrichment stimulated pathway-wide increase in carbon partitioning to phenylpropanoids. High CO{sub 2} plants had 11.8% more F-D phenolics, 19.3% more tannin, and 10% more lignin than ambient plants after adjusting for plant mass via analysis of covariance. In general, the results unequivocally support the predictions of the GDB{sub e} model. By way of contrast, results from many parallel studies on FACE trembling aspen, Populus tremuloides Michx., suggest that although 2 enrichment has consistently stimulated both photosynthesis and growth, it apparently did not

  20. Application of Balanced Scorecard

    OpenAIRE

    Langpaulová, Irena

    2011-01-01

    The concept of the Balanced Scorecard taking a part in the strategic management of a company, is a main focus of this thesis. There are the theoretical and methodological parts of the Balanced Scorecard characterized individually, as well as the development and the history of this concept. This thesis is dealing with a draft of the practical implementation of the mentioned methods. The practical part of the thesis is following the theoretical introduction where the practical part is focused o...

  1. Measuring the impact of prescribed fire management on the carbon balance of a flatwoods ecosystem in Kissimmee, Florida

    Science.gov (United States)

    Becker, K.; Hinkle, C.

    2012-12-01

    It has been well documented that terrestrial ecosystems have a great potential to store and sequester carbon. Therefore, a former ranch land at the Disney Wilderness Preserve (DWP), Kissimmee, Florida, USA is being restored to native ecosystems and managed to preserve biodiversity and increase carbon storage. Here, we present measurements of C flux from an eddy covariance system located in a longleaf pine flatwoods ecosystem at DWP. C flux measurements were taken at the site before, during, and after a prescribed fire event. C stock measurements were also taken for aboveground biomass immediately before and after the fire, as well as one year post fire. This study indicated that this ecosystem typically serves as a net sink of C. However, the system became a net source of C immediately following the fire event, with a ~40% loss of aboveground C stock, but recovered to a net sink of C within 6 weeks of the fire. Annually this ecosystem was found to serve as a net C sink even with a prescribed fire event, with annual net ecosystem productivity (NEP) of 508 g C/m2 in a non-fire year (2010) and 237 g C/m2 in a fire year (2011). In addition to the fire, it is important to note that the growing season of 2011 was anomalously dry, which likely hindered productivity, and thus the NEP of the fire year would probably be more similar to the non-fire year under more typical hydrologic conditions. Despite the variability of rainfall between years, this study shows that the longleaf pine flatwoods ecosystem provides the service of C sequestration even in the context of frequent prescribed fire management.

  2. A simplified method for the assessment of carbon balance in agriculture: an application in organic and conventional micro-agroecosystems in a long-term experiment in Tuscany, Italy

    Directory of Open Access Journals (Sweden)

    Giulio Lazzerini

    2014-06-01

    Full Text Available Many research works propose sophisticated methods to analyse the carbon balance, while only a few tools are available for the calculation of both greenhouse gas emissions and carbon sequestration with simplified methods. This paper describes a carbon balance assessment conducted at farm level with a simplified methodology, which includes calculations of both CO2 emissions and carbon sequestration in crop rotations. This carbon balance was tested in the Montepaldi Long Term Experiment (MOLTE trial in central Italy, where two agroecosystems managed with two different farming practices (organic vs conventional are compared. Both in terms of CO2eq emissions and carbon sequestration, this simplified method applied in our experiment provided comparable results to those yielded by complex methodologies reported in the literature. With regard to the crop rotation scheme applied in the reference period (2003-2007, CO2 emissions from various farm inputs were found to be significantly lower (0.74 Mg ha-1 in the organically managed system than in the conventionally managed system (1.76 Mg ha-1. The same trend was observed in terms of CO2eq per unit of product (0.30 Mg kg-1 in the organic system and 0.78 Mg kg-1 in the conventional system. In the conventional system the sources that contributed most to total emissions were direct and indirect emissions associated with the use of fertilisers and diesel fuel. Also the stock of sequestered carbon was significantly higher in the organic system (27.9 Mg ha-1 of C than in the conventional system (24.5 Mg ha-1 of C. The carbon sequestration rate did not show any significant difference between the two systems. It will be necessary to test further this methodology also in commercial farms and to validate the indicators to monitor carbon fluxes at farm level.

  3. Comparison of selected methods of establishing a balance of effects as part of an eco-balance. Activity report; Vergleich ausgewaehlter Methoden zur Wirkungsbilanz als Teil der Oekobilanz. Arbeitsbericht

    Energy Technology Data Exchange (ETDEWEB)

    Pick, E.; Guerzenich, D.; Langer, A.

    1999-11-01

    An eco-balance normally comprises a balance of facts and a balance of effects. The former takes stock of all mass and energy flows without analyzing them, while the latter attempts a quantification of their effects. So far, there is a lack of standardisation in the balance of effects. The investigation therefore attempted to discuss the available methods establishing a balance of effects and evaluate them with a view to their applicability and practicability. The investigations are based on the ISO 140140 ff. standards as these are the only ones that contain a systematic structure of a general eco-balance and are also internationally accepted. [German] Eine Oekobilanz wird heute normalerweise in eine Sachbilanz und in eine Wirkungsbilanz aufgeteilt. Die Sachbilanz stellt alle die vom System ausgeloesten oder verwendeten Stoff- und Energiestroeme zusammen, ohne diese zu bewerten. Die Wirkungsbilanz versucht im Anschluss daran die Auswirkungen der Stoff- und Energiestroeme hinsichtlich der interessierenden Umweltthemen zu quantifizieren. In einer letzten Phase wird schliesslich die Wirkungsbilanz hinsichtlich des Erkenntnisinteresses ausgewertet. Dadurch ist es moeglich, dass Ziele zur Verbesserung formuliert und Potentiale aufgedeckt werden koennen. Die Sachbilanz ist bisher weitestgehend genormt. Zur konkreten Wirkungsbilanzierung hingegen existieren zur Zeit viele verschiedene Herangehensweisen, und es wird daher auch eine Vielzahl von Methoden zu ihrer Durchfuehrung verwendet. Ziel dieser Arbeit ist es, in die diversen Methoden der Wirkungsbilanzierung einzufuehren und sie hinsichtlich der Anwendbarkeit und Praktikabilitaet zu bewerten. Dabei wird die Normreihe ISO 140140 ff. zugrundegelegt, da diese Normreihe als einzige den Aufbau einer Oekobilanz als Ganzes systematisch vorgibt und zudem international anerkannt ist. (orig.)

  4. Potential of forest management to reduce French carbon emissions - regional modelling of the French forest carbon balance from the forest to the wood.

    Science.gov (United States)

    Valade, A.; Luyssaert, S.; Bellassen, V.; Vallet, P.

    2015-12-01

    In France the low levels of forest harvest (40 Mm3 per year over a volume increment of 89Mm3) is frequently cited to push for a more intensive management of the forest that would help reducing CO2 emissions. This reasoning overlooks the medium-to-long-term effects on the carbon uptake at the national scale that result from changes in the forest's structure and delayed emissions from products decay and bioenergy burning, both determinant for the overall C fluxes between the biosphere and the atmosphere. To address the impacts of an increase in harvest removal on biosphere-atmosphere carbon fluxes at national scale, we build a consistent regional modeling framework to integrate the forest-carbon system from photosynthesis to wood uses. We aim at bridging the gap between regional ecosystem modeling and land managers' considerations, to assess the synergistic and antagonistic effects of management strategies over C-based forest services: C-sequestration, energy and material provision, fossil fuel substitution. For this, we built on inventory data to develop a spatial forest growth simulator and design a novel method for diagnosing the current level of management based on stand characteristics (density, quadratic mean diameter or exploitability). The growth and harvest simulated are then processed with a life cycle analysis to account for wood transformation and uses. Three scenarii describe increases in biomass removals either driven by energy production target (set based on national prospective with a lock on minimum harvest diameters) or by changes in management practices (shorter or longer rotations, management of currently unmanaged forests) to be compared with business as usual simulations. Our management levels' diagnostics quantifies undermanagement at national scale and evidences the large weight of ownership-based undermanagement with an average of 26% of the national forest (between 10% and 40% per species) and thus represents a huge potential wood resource

  5. Influence of forest stands on soil and ecosystem carbon stocks in the conditions of the European part of Russia

    Science.gov (United States)

    Kaganov, Vladimir

    2016-04-01

    Forest stands are one of the most important components of ecosystems, both in Russia and around the world and at the same time forest vegetation is able to provide environment-modifying effect on the occupied landscape and, in particular, on the soil cover. Currently, due to the large interest in the carbon cycle, there is a question about the influence of forest vegetation on carbon stocks in ecosystems and in particular in the soil cover. To perform the study we selected 9 objects located in the European part of Russia from the area of the southern taiga to the semi-desert zone: Novgorod region, Kostroma region, Moscow region (2 objects), Penza region, Voronezh region, Volgograd region (2 objects) and Astrakhan region. For studying the influence of forest vegetation on the soil`s carbon, we organized the following experiment scheme: in each of the objects two key sites were selected, so that they originally were in the same soil conditions and the difference between them was only in a course development of vegetation - forest or grass. One part of the experimental sites, presenting forest vegetation, were the restored forests on abandoned lands with the age of 70-200 years. The second part of the experimental sites were artificial forest plantations aged from 60 to 112 years planted on the originally treeless forest-steppe or steppe landscapes. Perennial hayfields, perennial abandoned agricultural landscapes and virgin steppe areas were used as reference sites with grass vegetation. For each forest site we estimated the major carbon pools: phytomass, mortmass (dead wood, dry grass), debris, litter and soil. All data were recalculated using the conversion factors in carbon stocks in t C ha-1. We collected soil samples every 10 cm until the depth of 50 cm, and then at 50-75 and 75-100 cm soil layers. Bulk density and total organic carbon were determined by CHN analyzer. As a result, the soil`s carbon was also calculated into t C ha-1. We found out that the total

  6. Phenology, canopy aging and seasonal carbon balance as related to delayed winter pruning of Vitis vinifera L. cv. Sangiovese grapevines

    Directory of Open Access Journals (Sweden)

    Matteo eGatti

    2016-05-01

    Full Text Available Manipulating or shifting annual grapevine growing cycle to offset limitations imposed by global warming is a must today, and delayed winter pruning is a tool to achieve it. However, no information is available about its physiological background, especially in relation to modifications in canopy phenology, demography and seasonal carbon budget. Mechanistic hypothesis underlying this work was that very late winter pruning can achieve significant postponement of phenological stages so that ripening might occur in a cooler period and, concurrently, ripening potential can be improved due to higher efficiency and prolonged longevity of the canopy. Variability in the dynamics of the annual cycle was created in mature potted cv. Sangiovese grapevines subjected to either standard winter pruning (SWP or late and very late winter pruning (LWP, VLWP performed when apical shoots on the unpruned canes were at the stage of 2 and 7 unfolded leaves. Vegetative growth, phenology and canopy net CO2 exchange (NCER was followed throughout the season.Despite LWP and VLWP induced a bud-burst delay of 17 and 31 days vs. SWP, the delay was fully offset at harvest for LWP and was reduced to 6 days in VLWP. LWP showed notably higher canopy efficiency as shorter time needed to reach maximum NCER/leaf area (22 days vs 34 in SWP, highest maximum NCER/leaf area (+37% as compared to SWP and higher NCER/leaf area rates from veraison to end of season. As a result, seasonal cumulated carbon in LWP was 17% higher than SWP. A negative functional relationship was also established between amount of leaf area removed at winter pruning and yield per vine and berry number per cluster. Although retarded winter pruning was not able to postpone late-season phenological stages under the warm conditions of this study, it showed a remarkable potential to limit yield while improving grape quality, thereby fostering the hypothesis that it could be used to replace time-consuming and costly

  7. Phenology, Canopy Aging and Seasonal Carbon Balance as Related to Delayed Winter Pruning of Vitis vinifera L. cv. Sangiovese Grapevines.

    Science.gov (United States)

    Gatti, Matteo; Pirez, Facundo J; Chiari, Giorgio; Tombesi, Sergio; Palliotti, Alberto; Merli, Maria C; Poni, Stefano

    2016-01-01

    Manipulating or shifting annual grapevine growing cycle to offset limitations imposed by global warming is a must today, and delayed winter pruning is a tool to achieve it. However, no information is available about its physiological background, especially in relation to modifications in canopy phenology, demography and seasonal carbon budget. Mechanistic hypothesis underlying this work was that very late winter pruning (LWP) can achieve significant postponement of phenological stages so that ripening might occur in a cooler period and, concurrently, ripening potential can be improved due to higher efficiency and prolonged longevity of the canopy. Variability in the dynamics of the annual cycle was created in mature potted cv. Sangiovese grapevines subjected to either standard winter pruning (SWP) or late and very late winter pruning (LWP, VLWP) performed when apical shoots on the unpruned canes were at the stage of 2 and 7 unfolded leaves. Vegetative growth, phenology and canopy net CO2 exchange (NCER) were followed throughout the season. Despite LWP and VLWP induced a bud-burst delay of 17 and 31 days vs. SWP, the delay was fully offset at harvest for LWP and was reduced to 6 days in VLWP. LWP showed notably higher canopy efficiency as shorter time needed to reach maximum NCER/leaf area (22 days vs. 34 in SWP), highest maximum NCER/leaf area (+37% as compared to SWP) and higher NCER/leaf area rates from veraison to end of season. As a result, seasonal cumulated carbon in LWP was 17% higher than SWP. A negative functional relationship was also established between amount of leaf area removed at winter pruning and yield per vine and berry number per cluster. Although retarded winter pruning was not able to postpone late-season phenological stages under the warm conditions of this study, it showed a remarkable potential to limit yield while improving grape quality, thereby fostering the hypothesis that it could be used to replace time-consuming and costly cluster

  8. Analysis of Metabolites and Carbon Balance in the Biofilteration of Cumene Using Loofa Sponge as Biofilter Media.

    Science.gov (United States)

    Shahi, Amrita; Rai, B N; Singh, R S

    2016-09-01

    A laboratory-scale biofilter study was performed to treat cumene-inoculated mixed culture of bacterial community and loofa sponge (Luffa cylindrica) as support media for a period of 120 days in five distinct phases. The removal efficiency was obtained in the range of 40-85 % with maximum elimination capacity of 700 g m(-3) h(-1) at the inlet load of 1167 g m(-3) h(-1). The result demonstrated that loofa sponge is good support media for the removal of cumene at higher loading rates. Loofa sponge was characterized via chemical analysis and analytical techniques such as XRD; FTIR; XPS; and CHN, and the result obtained confirms its suitability as biofilter media. The SEM results of loofa with inoculum shows the formation of a biofilm layer on the surface of loofa. The GC-MS analysis of leachate confirms the presence of different organic compounds such as acetaldehyde and 4-hydroxy-2-oxopentanoic acids which are stable metabolites during cumene biodegradation. About 12.69 % of carbon present in inlet cumene was converted to biomass.

  9. Effects of Sigma Anti-bonding Molecule Calcium Carbonate on bone turnover and calcium balance in ovariectomized rats.

    Science.gov (United States)

    Choi, So-Young; Park, Dongsun; Yang, Goeun; Lee, Sun Hee; Bae, Dae Kwon; Hwang, Seock-Yeon; Lee, Paul K; Kim, Yun-Bae; Kim, Ill-Hwa; Kang, Hyun-Gu

    2011-12-01

    This study was conducted to evaluate the effect of Sigma Anti-bonding Molecule Calcium Carbonate (SAC) as therapy for ovariectomy-induced osteoporosis in rats. Three weeks after surgery, fifteen ovariectomized Sprague-Dawley rats were divided randomly into 3 groups: sham-operated group (sham), ovariectomized group (OVX) and SAC-treatment group (OVX+SAC). The OVX+SAC group was given drinking water containing 0.0012% SAC for 12 weeks. Bone breaking force and mineralization as well as blood parameters related to the bone metabolism were analyzed. In OVX animals, blood concentration of 17β-estradiol decreased significantly, while osteocalcin and type I collagen C-terminal telopeptides (CTx) increased. Breaking force, bone mineral density (BMD), calcium and phosphorus in femurs, as well as uterine and vaginal weights, decreased significantly following OVX. However, SAC treatment (0.0012% in drinking water) not only remarkably restored the decreased 17β-estradiol and increased osteocalcin and CTx concentrations, but also recovered decreased femoral breaking force, BMD, calcium and phosphorus, although it did not reversed reproductive organ weights. It is suggested that SAC effectively improve bone density by preventing bone turnover mediated osteocalcin, CTx and minerals, and that it could be a potential candidate for therapy or prevention of postmenopausal osteoporosis.

  10. Water balance and carbon sink strength of an European savannah-type woodland during the drought year 2012

    Science.gov (United States)

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

    2013-12-01

    Vc,max. The bulk reduction takes place in summer whereas only little reduction occurs during the spring drought anomaly. Understorey GPP was reduced by 87% and was affected rather instantaneously already in winter. Overall is the ecosystem a carbon sink in both years but with a reduced sink strength by 34% in the drought year 2012. In summary, the savannah-type ecosystem was strongly affected by the drought in 2012. Water availability was reduced due to a strong decrease in precipitation with little effect on evapotranspiration and canopy conductance. The carbon sink strength was strongly diminished by an early die-back of the understory vegetation and a reduced maximum carboxylation rate of the Q. suber trees.

  11. An isotope mass balance model for the correlation of freshwater bivalve shell (Unio pictorum carbonate δ18O to climatic conditions and water δ18O in Lake Balaton (Hungary

    Directory of Open Access Journals (Sweden)

    Gabriella SCHÖLL-BARNA

    2011-08-01

    Full Text Available The oxygen isotope composition of bivalve shells (δ18Oshell can potentially record environmental variability of shallow lakes and therefore it has been extensively used as a proxy in the reconstruction of past climate and environmental conditions. As δ18Oshell reflects - besides the water temperature - the oxygen isotope composition of lake water (δ18OL, it is required to interpret the quality and impact of parameters influencing the δ18OL. Using the isotope mass balance model, I tested the hypothesis that Balaton lake water δ18O variability can be described as a result of the combined effects of three main climatic parameters such as river runoff, precipitation and evaporation. I calculated δ18OL time series for the period 1999-2008 for the whole water body at Siófok (eastern part of Lake Balaton, Hungary based on measured precipitation, inflow and evaporation amount and measured inflow, precipitation δ18O and calculated vapour δ18O data. The comparison of the modelled δ18OL time series to measured surface δ18OL data revealed that δ18O of Balaton water is sensitive for variation of climatic parameters. This variability is most striking at the surface, while according to the results of the model, the whole water body itself is less sensitive. Monthly differences suggest that generally during summer the whole water body is mixed up, while moderate isotope stratification (0.3-0.7‰ difference between surface and whole water body can be assumed in early spring and autumn. Predictions of shell δ18O values were made using the measured surface water δ18O data and the modelled δ18O values for the whole water body. High-resolution sampling was conducted on two Unio pictorum shells covering the period of 2001-2008, and both predictions were compared to measured shell δ18O records. The results showed that the prediction for the whole water body gives a better fit to the measured shell δ18O, suggesting that the whole water body better

  12. Unchanged carbon balance driven by equivalent responses of production and respiration to climate change in a mixed-grass prairie.

    Science.gov (United States)

    Xu, Xia; Shi, Zheng; Chen, Xuecheng; Lin, Yang; Niu, Shuli; Jiang, Lifen; Luo, Ruiseng; Luo, Yiqi

    2016-05-01

    Responses of grassland carbon (C) cycling to climate change and land use remain a major uncertainty in model prediction of future climate. To explore the impacts of global change on ecosystem C fluxes and the consequent changes in C storage, we have conducted a field experiment with warming (+3 °C), altered precipitation (doubled and halved), and annual clipping at the end of growing seasons in a mixed-grass prairie in Oklahoma, USA, from 2009 to 2013. Results showed that although ecosystem respiration (ER) and gross primary production (GPP) negatively responded to warming, net ecosystem exchange of CO2 (NEE) did not significantly change under warming. Doubled precipitation stimulated and halved precipitation suppressed ER and GPP equivalently, with the net outcome being unchanged in NEE. These results indicate that warming and altered precipitation do not necessarily have profound impacts on ecosystem C storage. In addition, we found that clipping enhanced NEE due to a stronger positive response of GPP compared to ER, indicating that clipping could potentially be an effective land practice that could increase C storage. No significant interactions between warming, altered precipitation, and clipping were observed. Meanwhile, we found that belowground net primary production (BNPP) in general was sensitive to climate change and land use though no significant changes were found in NPP across treatments. Moreover, negative correlations of the ER/GPP ratio with soil temperature and moisture did not differ across treatments, highlighting the roles of abiotic factors in mediating ecosystem C fluxes in this grassland. Importantly, our results suggest that belowground C cycling (e.g., BNPP) could respond to climate change with no alterations in ecosystem C storage in the same period.

  13. Significant contributions of fungal spores to the organic carbon and to the aerosol mass balance of the urban atmospheric aerosol

    Science.gov (United States)

    Bauer, Heidi; Schueller, Elisabeth; Weinke, Gert; Berger, Anna; Hitzenberger, Regina; Marr, Iain L.; Puxbaum, Hans

    Fungal spores are ubiquitous components of atmospheric aerosols and are therefore also contributors to the organic carbon (OC) component and to the mass of PM 10 (PM—particulate matter) aerosols. In this study we use spore counts and an experimentally derived factor of 13 pg C and of 33 pg fresh weight per spore for assessing quantitatively the contribution to OC and PM 10. The concentrations of airborne fungal spores were determined at a suburban (Schafberg) and a traffic-dominated urban site (Rinnböckstrasse) in Vienna, Austria, during spring and summer. Fungal spores OC ranged from 22 to 677 ng m -3 with a summer mean value of around 350 ng m -3 at the suburban site and 300 ng m -3 at the urban traffic site. At the suburban site fungal spores contributed on average 6% in spring and 14% in summer to aerosol OC mass concentration. At the traffic-dominated site fungal spores accounted for 2% of OC in spring and for 8% in summer. The fungal contribution to PM 10 was also notable and amounted to 3% and 7% at the suburban and to 1% and 4% at the urban site in spring and summer, respectively. Impactor measurements of OC at the suburban site showed that in summer fungal spores were predominant contributors to the coarse aerosol OC, and accounted on average for 60% of the OC in the PM 2-10 fraction. Fungal spores thus can be regarded as main components to PM 10, total OC and, most importantly, coarse OC even in urban areas.

  14. Microbial carbon recycling - an underestimated process controlling soil carbon dynamics - Part 1: A long-term laboratory incubation experiment

    Science.gov (United States)

    Basler, A.; Dippold, M.; Helfrich, M.; Dyckmans, J.

    2015-10-01

    Independent of its chemical structure carbon (C) persists in soil for several decades, controlled by stabilization and recycling. To disentangle the importance of the two factors on the turnover dynamics of soil sugars, an important compound of soil organic matter (SOM), a 3-year incubation experiment was conducted on a silty loam soil under different types of land use (arable land, grassland and forest) by adding 13C-labelled glucose. The compound-specific isotope analysis of soil sugars was used to examine the dynamics of different sugars during incubation. Sugar dynamics were dominated by a pool of high mean residence times (MRT) indicating that recycling plays an important role for sugars. However, this was not substantially affected by soil C content. Six months after label addition the contribution of the label was much higher for microbial biomass than for CO2 production for all examined land use types, corroborating that substrate recycling was very effective within the microbial biomass. Two different patterns of tracer dynamics could be identified for different sugars: while fucose and mannose showed highest label contribution at the beginning of the incubation with a subsequent slow decline, galactose and rhamnose were characterized by slow label incorporation with subsequently constant levels, which indicates that recycling is dominating the dynamics of these sugars. This may correspond to (a) different microbial growing strategies (r and K-strategist) or (b) location within or outside the cell membrane (lipopolysaccharides vs. exopolysaccharides) and thus be subject of different re-use within the microbial food web. Our results show how the microbial community recycles substrate very effectively and that high losses of substrate only occur during initial stages after substrate addition. This study indicates that recycling is one of the major processes explaining the high MRT observed for many SOM fractions and thus is crucial for understanding the

  15. Carbon composites based on multiaxial multiply stitched preforms. Part V: geometry of sheared biaxial fabrics

    NARCIS (Netherlands)

    Loendersloot, R.; Lomov, S.V.; Akkerman, R.; Verpoest, I.

    2006-01-01

    The geometry of multiaxial multiply carbon reinforcement under shear deformation is studied. A description based on the distortions of the fibres bundles, induced by the stitch yarn is proposed. These distortions are recognised to be dominant for the impregnation behaviour and the damage initiation,

  16. CARBON-FIBRE-REINFORCED POLYMER PARTS EFFECT ON SPACECRAFT OPTOELECTRONIC MODULE LENS SCATTERING

    Directory of Open Access Journals (Sweden)

    S. S. Kolasha

    2016-01-01

    Full Text Available Spacecraft optoelectronic modules traditionally have aluminum alloy or titanium alloy casing which substantial weight increases fuel consumption required to put them into orbit and, consequently, total cost of the project. Carbon fiber reinforced polymer based composite constructive materials is an efficient solution that allows reducing weight and dimensions of large optoelectronic modules 1,5–3 times and the coefficient of linear thermal expansion 15–20 times if compared with metals. Optical characteristic is a crucial feature of carbon-fibre-reinforced polymer that determines composite material interaction with electromagnetic emission within the optical range. This work was intended to develop a method to evaluate Carbon fiber reinforced polymer optoelectronic modules casing effect on lens scattering by computer simulation with Zemax application software package. Degrees of scattered, reflected and absorbed radiant flux effect on imaging quality are described here. The work included experimental study in order to determine bidirectional reflectance distribution function by goniometric method for LUP-0.1 carbon fabric check test pieces of EDT-69U epoxy binder with EPOFLEX-0.4 glue layer and 5056-3.5-23-A aluminium honeycomb filler. The scattered emission was registered within a hemisphere above the check test piece surface. Optical detection direction was determined with zenith (0º < θ < 90º and azimuth (0º < φ < 180º angles with 10° increment. The check test piece surface was proved to scatter emission within a narrow angle range (approximately 20° with clear directivity. Carbon fiber reinforced polymers was found to feature integrated reflectance coefficient 3 to 4 times greater than special coatings do. 

  17. CO2-induced dissolution of low permeability carbonates. Part I: Characterization and experiments

    Science.gov (United States)

    Smith, Megan M.; Sholokhova, Yelena; Hao, Yue; Carroll, Susan A.

    2013-12-01

    The effect of elevated dissolved CO2 concentrations on compositionally and structurally distinct carbonate sample cores from the Weyburn-Midale CO2-enhanced oil recovery and storage site (Canada) was measured from analysis of 3-D sample characterization and fluid chemistry data from core-flood experiments. Experimental conditions (60 °C; 24.8 MPa confining pressure) and brine composition were chosen to mimic in situ reservoir conditions. Mineralogy and pore space distributions within the eight individual cores were characterized with X-ray computed microtomography and scanning electron microscopy both before and after exposure to brine with 0.5 ⩽ pCO2 ⩽ 3 MPa, while solution chemistry and differential fluid pressures were monitored during experiments. Our experimental study aimed to quantify the relationship between fluid flow, heterogeneity, and reaction specific to carbon storage at the Weyburn-Midale field by integrating characterization imaging, pressure data, and solution chemistry. Through the use of non-invasive microtomographic imaging, a variety of dissolution behaviors were observed, with variable effects on the evolution of solution chemistry and permeability as a result of heterogeneity within these two relatively low permeability carbonate samples. Similar-sized, evenly distributed pores, and steadily advancing dissolution fronts suggested that uniform flow velocities were maintained throughout the duration of the higher permeability “Marly” dolostone core experiments. The development of unstable dissolution fronts and fast pathways occurred in the “Vuggy” sample experiments when fluid velocities varied widely within the sample (as a result of increased pore structure heterogeneity). The overall effect of fast pathway development was to increase bulk permeability values by several orders of magnitude, allowing CO2-acidified fluids to travel through the cores largely unmodified by carbonate mineral reaction, as indicated by a lack of change

  18. Computational modeling of elastic properties of carbon nanotube/polymer composites with interphase regions. Part II: Mechanical modeling

    KAUST Repository

    Han, Fei

    2014-01-01

    We present two modeling approaches for predicting the macroscopic elastic properties of carbon nanotubes/polymer composites with thick interphase regions at the nanotube/matrix frontier. The first model is based on local continuum mechanics; the second one is based on hybrid local/non-local continuum mechanics. The key computational issues, including the peculiar homogenization technique and treatment of periodical boundary conditions in the non-local continuum model, are clarified. Both models are implemented through a three-dimensional geometric representation of the carbon nanotubes network, which has been detailed in Part I. Numerical results are shown and compared for both models in order to test convergence and sensitivity toward input parameters. It is found that both approaches provide similar results in terms of homogenized quantities but locally can lead to very different microscopic fields. © 2013 Elsevier B.V. All rights reserved.

  19. Carbon dioxide effects research and assessment program. A comprehensive plan. Part I. The global carbon cycle and climatic effects of increasing carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Slade, David H.

    1980-08-01

    Initial plans for research of the carbon dioxide (CO/sub 2/) and climate issue were prepared in 1978 and were reviewed extensively at that time by federal agencies and members of the scientific community. Since then the plans have been used to guide early phases of the Department of Energy's and the nation's efforts related to this issue. This document represents a revision of the 1978 plan to (a) reflect recent ideas and strategies for carbon cycle research, and (b) expand the scope of research on climatic responses to increasing atmospheric concentrations of CO/sub 2/. The revised plan takes into account a number of investigations already being supported by various agencies, and it attempts to build on or add to existing research where there is a crucial need for information directly related to the CO/sub 2/ issue. It should be recognized that this document is the first section of a comprehensive plan on the overall consequences of increasing concentrations of CO/sub 2/, and includes guidelines for research on the Global Carbon Cycle and Climatic Effects of Increasing CO/sub 2/.

  20. Improvements of Brazilian carbonization industry as part of the creation of a global biomass economy

    Energy Technology Data Exchange (ETDEWEB)

    Pelaez-Samaniego, M.R. [Energy Planning Systems, Faculty of Mechanical Engineering, UNICAMP, Campinas, SP (Brazil); Faculty of Chemical Sciences, University of Cuenca (Ecuador); Garcia-Perez, M. [University of Georgia (United States); Cortez, L.B. [Energy Planning Systems, Faculty of Mechanical Engineering, UNICAMP, Campinas, SP (Brazil); Rosillo-Calle, F. [Imperial College London (United Kingdom); Mesa, J. [Bioware Technology (Brazil)

    2008-05-15

    Brazil is the largest world charcoal producer. Surface kilns with semi-spherical form built with bricks with or without recovery of by-products called 'Tail Quente' are the most important systems used for charcoal production. The un-recovered pyrolysis products released to environment by this technology are major pollutants. Some alternatives integrating existing or improved carbonization units within a global biomass economy are presented. In these alternatives the carbonization reactors can be used for primary biomass conversion, for densification, for power and heat production or as core technology in new bio-refineries. Some of the technical and economical limitations to implement these concepts are discussed. (author)

  1. Estimating agro-ecosystem carbon balance of northern Japan, and comparing the change in carbon stock by soil inventory and net biome productivity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xi, E-mail: icy124@hotmail.com [School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu 610500 (China); Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Toma, Yo [Faculty of Agriculture, Ehime University, 3-5-7, Tarumi, Matsuyama 790-8566, Ehime (Japan); Yeluripati, Jagadeesh [The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, Scotland (United Kingdom); Iwasaki, Shinya [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan); Bellingrath-Kimura, Sonoko D. [Leibniz Centre for Agricultural Landscape Research, Institute of Land Use Systems (Germany); Jones, Edward O. [Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London (United Kingdom); Hatano, Ryusuke [Graduate school of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo 060-8589 (Japan)

    2016-06-01

    Soil C sequestration in croplands is deemed to be one of the most promising greenhouse gas mitigation options for agriculture. We have used crop-level yields, modeled heterotrophic respiration (Rh) and land use data to estimate spatio-temporal changes in regional scale net primary productivity (NPP), plant C inputs, and net biome productivity (NBP) in northern Japan's arable croplands and grasslands for the period of 1959–2011. We compared the changes in C stocks derived from estimated NBP and using repeated inventory datasets for each individual land use type from 2005 to 2011. For the entire study region of 2193 ha, overall annual plant C inputs to the soil constituted 37% of total region NPP. Plant C inputs in upland areas (excluding bush/fallow) could be predicted by climate variables. Overall NBP for all land use types increased from − 1.26 Mg C ha{sup −1} yr{sup −1} in 1959–0.26 Mg C ha{sup −1} yr{sup −1} in 2011. However, upland and paddy fields showed a decreased in NBP over the period of 1959–2011, under the current C input scenario. From 1988, an increase in agricultural abandonment (bush/fallow) and grassland cover caused a slow increase in the regional C pools. The comparison of carbon budgets using the NBP estimation method and the soil inventory method indicated no significant difference between the two methods. Our results showed C loss in upland crops, paddy fields and sites that underwent land use change from paddy field to upland sites. We also show C gain in grassland from 2005 to 2011. An underestimation of NBP or an overestimation of repeated C inventories cannot be excluded, but either method may be suitable for tracking absolute changes in soil C, considering the uncertainty associated with these methods. - Highlights: • We compared C stocks change by two methods: (i) net biome productivity (NBP) and (ii) soil inventory. • Variation in net primary productivity (NPP), plant C input, NBP can be predicted by climate

  2. Structural CNT Composites. Part I; Developing a Carbon Nanotube Filament Winder

    Science.gov (United States)

    Sauti, Godfrey; Kim, Jae-Woo; Wincheski, Russell A.; Antczak, Andrew; Campero, Jamie C.; Luong, Hoa H.; Shanahan, Michelle H.; Stelter, Christopher J.; Siochi, Emilie J.

    2015-01-01

    Carbon nanotube (CNT) based materials promise advances in the production of high strength and multifunctional components for aerospace and other applications. Specifically, in tension dominated applications, the latest CNT based filaments are yielding composite properties comparable to or exceeding composites from more established fibers such as Kevlar and carbon fiber. However, for the properties of these materials to be fully realized at the component level, suitable manufacturing processes have to be developed. These materials handle differently from conventional fibers, with different wetting characteristics and behavior under load. The limited availability of bulk forms also requires that the equipment be scaled down accordingly to tailor the process development approach to material availability. Here, the development of hardware and software for filament winding of carbon nanotube based tapes and yarns is described. This hardware features precision guidance of the CNT material and control of the winding tension over a wide range in an open architecture that allows for effective process control and troubleshooting during winding. Use of the filament winder to develop CNT based Composite Overwrapped Pressure Vessels (COPVs) shall also be discussed.

  3. Photochromism of Dihydroindolizines Part XI: Synthesis of Novel Carbon-Rich Photochromic Dihydroindolizines-Based Potential Electronic Devices

    Directory of Open Access Journals (Sweden)

    Saleh Abdel-Mgeed Ahmed

    2008-01-01

    Full Text Available Novel carbon-rich photochromic dihydroindolizine (DHI derivatives substituted in the fluorene part (region A in addition to the new spirocyclopropene 6 have been synthesized. The synthesis of dimethyl 2′,7′-diethynylspiro[cycloprop[2]ene-1,9′-fluorene]-2,3-dicarboxylate precursor 6 was accomplished in five steps, starting with the literature known conversion of fluorene to 2,7-dibromo-9H-fluoren-9-one in 56% yield over three steps. The chemical structures of the new synthesized materials have been elucidated by both analytical and spectroscopic tools. Three alterative synthetic pathways for the synthesis of DHI 9 have been established.

  4. CO2-induced dissolution of low permeability carbonates. Part II: Numerical modeling of experiments

    Science.gov (United States)

    Hao, Yue; Smith, Megan; Sholokhova, Yelena; Carroll, Susan

    2013-12-01

    We used the 3D continuum-scale reactive transport models to simulate eight core flood experiments for two different carbonate rocks. In these experiments the core samples were reacted with brines equilibrated with pCO2 = 3, 2, 1, 0.5 MPa (Smith et al., 2013 [27]). The carbonate rocks were from specific Marly dolostone and Vuggy limestone flow units at the IEAGHG Weyburn-Midale CO2 Monitoring and Storage Project in south-eastern Saskatchewan, Canada. Initial model porosity, permeability, mineral, and surface area distributions were constructed from micro tomography and microscopy characterization data. We constrained model reaction kinetics and porosity-permeability equations with the experimental data. The experimental data included time-dependent solution chemistry and differential pressure measured across the core, and the initial and final pore space and mineral distribution. Calibration of the model with the experimental data allowed investigation of effects of carbonate reactivity, flow velocity, effective permeability, and time on the development and consequences of stable and unstable dissolution fronts. The continuum scale model captured the evolution of distinct dissolution fronts that developed as a consequence of carbonate mineral dissolution and pore scale transport properties. The results show that initial heterogeneity and porosity contrast control the development of the dissolution fronts in these highly reactive systems. This finding is consistent with linear stability analysis and the known positive feedback between mineral dissolution and fluid flow in carbonate formations. Differences in the carbonate kinetic drivers resulting from the range of pCO2 used in the experiments and the different proportions of more reactive calcite and less reactive dolomite contributed to the development of new pore space, but not to the type of dissolution fronts observed for the two different rock types. The development of the dissolution front was much more

  5. 2013 social balance sheet

    OpenAIRE

    Pierrette Heuse

    2014-01-01

    The transposition into national law of Directive 2013/34/EU on the annual financial statements of companies, expected by no later than July 2015, could alter the statistical obligations on small firms in connection with the filing of their annual accounts. In any case, the social balance sheet can no longer form an integral part of their accounts. Nevertheless, it contains original information whose usefulness is highlighted, on the basis of the social balance sheets for 2012, by examining th...

  6. Balancing Audio

    DEFF Research Database (Denmark)

    Walther-Hansen, Mads

    2016-01-01

    This paper explores the concept of balance in music production and examines the role of conceptual metaphors in reasoning about audio editing. Balance may be the most central concept in record production, however, the way we cognitively understand and respond meaningfully to a mix requiring balance...... is not thoroughly understood. In this paper I treat balance as a metaphor that we use to reason about several different actions in music production, such as adjusting levels, editing the frequency spectrum or the spatiality of the recording. This study is based on an exploration of a linguistic corpus of sound...

  7. PHASE EQUILIBRIA INVESTIGATIONS OF BINARY, TERNARY, AND HIGHER ORDER SYSTEMS. PART 2. EFFECT OF RHENIUM AND ALUMINUM ADDITIONS ON THE METAL-RICH EQUILIBRIA IN THE TITANIUM-MOLYBDENIUM-CARBON AND TITANIUM-NIOBIUM-CARBON SYSTEMS

    Science.gov (United States)

    The solid state phase equilibria of the metal-rich regions of the Titanium-Molybdenum-Carbon and Titanium-Niobium-Carbon systems with up to 12 At...Rhenium and 10 At.% Aluminum additions, respectively, have been determined on hot pressed, heat treated, and in part arc melted alloys. The phase ... equilibria in the metal-rich regions, with these additions, is practically unchanged over that of the ternary Titanium-Molybdenum-Carbon and Titanium

  8. Applying hot-wire anemometry to directly measure the water balance in a proton exchange membrane fuel cell - Part 2: Experimental

    DEFF Research Database (Denmark)

    Al Shakhshir, Saher; Andreasen, Søren Juhl; Berning, Torsten

    2016-01-01

    can be directly converted into the fuel cell water balance. In this work an ex-situ experimental investigation is performed to examine the effect of the wire diameter and the outlet pipe diameter on the voltage signal. For a laboratory fuel cell where the mass flow rate the anode outlet is small......In order to better understand and more accurately measure the water balance in a proton exchange membrane fuel cell, our group has recently proposed to apply hot wire anemometry in the fuel cell's anode outlet. It was theoretically shown that the electrical signal obtained from the hot wire sensor...

  9. Variability in terrestrial carbon sinks over two decades: Part 2 — Eurasia

    Science.gov (United States)

    Potter, C.; Klooster, S.; Tan, P.; Steinbach, M.; Kumar, V.; Genovese, V.

    2005-12-01

    We have analyzed 17 yr (1982-1998) of net carbon flux predictions from a simulation model based on satellite observations of monthly vegetation cover. The NASA-CASA model was driven by vegetation cover properties derived from the Advanced Very High Resolution Radiometer and radiative transfer algorithms that were developed for the Moderate Resolution Imaging Spectroradiometer (MODIS). We report that although the terrestrial ecosystem sink for atmospheric CO 2 for the Eurasian region has been fairly consistent at between 0.3 and 0.6 Pg C per year since 1988, high interannual variability in net ecosystem production (NEP) fluxes can be readily identified at locations across the continent. Ten major areas of highest variability in NEP were detected: eastern Europe, the Iberian Peninsula, the Balkan states, Scandinavia, northern and western Russia, eastern Siberia, Mongolia and western China, and central India. Analysis of climate anomalies over this 17-yr time period suggests that variability in precipitation and surface solar irradiance could be associated with trends in carbon sink fluxes within such regions of high NEP variability.

  10. Development of carbon fiber staves for the strip part of the PANDA micro vertex detector

    Energy Technology Data Exchange (ETDEWEB)

    Quagli, Tommaso; Brinkmann, Kai-Thomas [II. Physikalisches Institut, Justus-Liebig Universitaet Giessen (Germany); Fracassi, Vincenzo; Grunwald, Dirk; Rosenthal, Eberhard [ZEA-1, Forschungszentrum Juelich GmbH, Juelich (Germany); Collaboration: PANDA-Collaboration

    2015-07-01

    PANDA is a key experiment of the future FAIR facility, under construction in Darmstadt, Germany. It will study the collisions between an antiproton beam and a fixed proton or nuclear target. The Micro Vertex Detector (MVD) is the innermost detector of the apparatus and is composed of four concentric barrels and six forward disks, instrumented with silicon hybrid pixel detectors and double-sided silicon microstrip detectors; its main task is the identification of primary and secondary vertices. The central requirements include high spatial and time resolution, trigger-less readout with high rate capability, good radiation tolerance and low material budget. Because of the compact layout of the system, its integration poses significant challenges. The detectors in the strip barrels will be supported by a composite structure of carbon fiber and carbon foam; a water-based cooling system embedded in the mechanical supports will be used to remove the excess heat from the readout electronics. In this contribution the design of the barrel stave and the ongoing development of some hardware components related to its integration will be presented.

  11. Balanced sampling

    NARCIS (Netherlands)

    Brus, D.J.

    2015-01-01

    In balanced sampling a linear relation between the soil property of interest and one or more covariates with known means is exploited in selecting the sampling locations. Recent developments make this sampling design attractive for statistical soil surveys. This paper introduces balanced sampling

  12. Balancing Work and Family: A Panel Analysis of the Impact of Part-Time Work on the Experience of Time Pressure

    Science.gov (United States)

    Laurijssen, Ilse; Glorieux, Ignace

    2013-01-01

    In this article we consider the consequences of work-family reconciliation, in terms of the extent to which the adjustment of the labour market career to family demands (by women) contributes to a better work-life balance. Using the Flemish SONAR-data, we analyse how changes in work and family conditions between the age of 26 and 29 are related to…

  13. The energy balance experiment EBEX-2000. Part II: Intercomparison of eddy-covariance sensors and post-field data processing methods

    NARCIS (Netherlands)

    Mauder, M.; Oncley, S.P.; Vogt, R.; Weidinger, T.; Ribeiro, L.; Bernhofer, C.; Foken, T.; Kohsiek, W.; Bruin, de H.A.R.; Liu, H.

    2007-01-01

    The eddy-covariance method is the primary way of measuring turbulent fluxes directly. Many investigators have found that these flux measurements often do not satisfy a fundamental criterion¿closure of the surface energy balance. This study investigates to what extent the eddy-covariance measurement

  14. Influences of changing land use and CO 2 concentration on ecosystem and landscape level carbon and water balances in mountainous terrain of the Stubai Valley, Austria

    Science.gov (United States)

    Tenhunen, J.; Geyer, R.; Adiku, S.; Reichstein, M.; Tappeiner, U.; Bahn, M.; Cernusca, A.; Dinh, N. Q.; Kolcun, O.; Lohila, A.; Otieno, D.; Schmidt, M.; Schmitt, M.; Wang, Q.; Wartinger, M.; Wohlfahrt, G.

    2009-05-01

    A process-based spatial simulation model was used to estimate gross primary production, ecosystem respiration, net ecosystem CO 2 exchange and water use by the vegetation in Stubai Valley, Austria at landscape scale. The simulations were run for individual years from early spring to late fall, providing estimates in grasslands for carbon gain, biomass and leaf area development, allocation of photoproducts to the below ground ecosystem compartment, and water use. In the case of evergreen coniferous forests, gas exchange is estimated, but spatial simulation of growth over the single annual cycles is not included. Spatial parameterization of the model is derived for forest LAI based on remote sensing, for soil characteristics by generalization from spatial surveys and for climate drivers from observations at monitoring stations along the elevation gradient and from modelling of incident radiation in complex terrain. Validation of the model was carried out at point scale, and was based on comparison of model output at selected locations with observations along elevation gradients in Stubai Valley and Berchtesgaden National Park, Germany as well as with known trends in ecosystem response documented in the literature. The utility of the model for describing long-term changes in carbon and water balances at landscape scale is demonstrated in the context of land use change that occurred between 1861 and 2002 in Stubai Valley. During this period, coniferous forest increased in extent by ca. 11% of the vegetated area of 1861, primarily in the subalpine zone. Managed grassland decreased by 46%, while abandoned grassland and natural alpine mats increased by 14 and 11%, respectively. At point scale, the formulated model predicts higher canopy conductance in 1861 due to lower atmospheric CO 2 concentration which opens stomata. As a result, water use at point scale decreased by ca. 8% in 2002 in the valley bottoms versus 10% at tree line. At landscape level, the decrease in water

  15. Convergence of the effect of root hydraulic functioning and root hydraulic redistribution on ecosystem water and carbon balance across divergent forest ecosystems

    Science.gov (United States)

    domec, J.; King, J. S.; Ogée, J.; Noormets, A.; Warren, J.; Meinzer, F. C.; Sun, G.; Jordan-Meille, L.; Martineau, E.; Brooks, R. J.; Laclau, J.; Battie Laclau, P.; McNulty, S.

    2012-12-01

    trees to droughts. Under future conditions, T is predicted to stay the same at the Duke mixed hardwood forest, but to decline slightly at the coastal loblolly pine plantation and slightly increase at the old-growth ponderosa pine stand and the eucalyptus plantation. As a consequence, water use efficiency in all sites was predicted to improve dramatically under future climate conditions. Our simulations also showed that the negative effect of drier nights on HR would be greater under future climate conditions. Assuming no increase in stomatal control with increasing drier nights, increased vapor pressure deficit at night under future conditions was sufficient to drive significant nighttime T at all sites , which reduced HR, because the plant and the atmosphere became a sink for hydraulically redistributed water . We concluded that the predicted reductions in HR under future climate conditions are expected to play an important regulatory role in land-atmosphere interactions by affecting whole ecosystem carbon and water balance. We suggest that root distribution should be treated dynamically in response to climate change and that HR and its interactions with rooting depth and soil texture should be implemented in soil-vegetation-atmosphere transfer models.

  16. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 5

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Shea, Winton

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or {approx}28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In

  17. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 3

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Shea, Winton

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or ~28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In addition to

  18. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 4

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Shea, Winton

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or {approx}28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In

  19. Effect of Carbon Nanofiber Heat Treatment on Physical Properties of Polymeric Nanocomposites—Part I

    Directory of Open Access Journals (Sweden)

    Khalid Lafdi

    2007-01-01

    Full Text Available The definition of a nanocomposite material has broadened significantly to encompass a large variety of systems made of dissimilar components and mixed at the nanometer scale. The properties of nanocomposite materials also depend on the morphology, crystallinity, and interfacial characteristics of the individual constituents. In the current work, vapor-grown carbon nanofibers were subjected to varying heat-treatment temperatures. The strength of adhesion between the nanofiber and an epoxy (thermoset matrix was characterized by the flexural strength and modulus. Heat treatment to 1800C∘ demonstrated maximum improvement in mechanical properties over that of the neat resin, while heat-treatment to higher temperatures demonstrated a slight decrease in mechanical properties likely due to the elimination of potential bonding sites caused by the elimination of the truncated edges of the graphene layers. Both the electrical and thermal properties of the resulting nanocomposites increased in conjunction with the increasing heat-treatment temperature.

  20. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Winton, Shea

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or ~28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In addition to

  1. An Industrial-Based Consortium to Develop Premium Carbon Products from Coal Final Report - Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Bruce; Winton, Shea

    2010-12-31

    Since 1998, The Pennsylvania State University successfully managed the Consortium for Premium Carbon Products from Coal (CPCPC), which was a vehicle for industry-driven research on the promotion, development, and transfer of innovative technologies on premium carbon products from coal to the U.S. industry. The CPCPC was an initiative led by Penn State, its cocharter member West Virginia University (WVU), and the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL), who also provided the base funding for the program, with Penn State responsible for consortium management. CPCPC began in 1998 under DOE Cooperative Agreement No. DE-FC26-98FT40350. This agreement ended November 2004 but the CPCPC activity continued under cooperative agreement No. DE-FC26-03NT41874, which started October 1, 2003 and ended December 31, 2010. The objective of the second agreement was to continue the successful operation of the CPCPC. The CPCPC enjoyed tremendous success with its organizational structure, which included Penn State and WVU as charter members, numerous industrial affiliate members, and strategic university affiliate members together with NETL, forming a vibrant and creative team for innovative research in the area of transforming coal to carbon products. The key aspect of CPCPC was its industry-led council that selected proposals submitted by CPCPC members to ensure CPCPC target areas had strong industrial support. CPCPC had 58 member companies and universities engaged over the 7-year period of this contract. Members were from 17 states and five countries outside of the U.S. During this period, the CPCPC Executive Council selected 46 projects for funding. DOE/CPCPC provided $3.9 million in funding or an average of $564,000 per year. The total project costs were $5.45 million with $1.5 million, or ~28% of the total, provided by the members as cost share. Total average project size was $118,000 with $85,900 provided by DOE/CPCPC. In addition to

  2. The sum of the parts: can we really reduce carbon emissions through individual behaviour change?

    Science.gov (United States)

    Reynolds, Lucy

    2010-01-01

    Individuals are increasingly being urged to 'do their bit' in the fight against climate change, with governments and pro-environmentalists insisting that the collective impact of small behaviour changes will result in a meaningful reduction in global carbon emissions. The following paper considers this debate, as well as offering personal contributions from two leading environmentalists: Dr Doug McKenzie-Mohr, environmental psychologist and author of Fostering Sustainable Behavior: Community-Based Social Marketing; and Dr Tom Crompton, change strategist for WWF and co-author of Meeting Environmental Challenges: The Role of Human Identity, who argues for the role of intrinsic value systems in achieving sustainable behaviour change. As well as considering the responsibility of the individual in mitigating climate change, the paper introduces the discipline of social marketing as an effective tool for facilitating individual behaviour change, drawing on evidence from the field to recommend the key characteristics of effective behaviour change programmes.

  3. Kinetic bottlenecks to chemical exchange rates for deep-sea animals - Part 2: Carbon Dioxide

    Science.gov (United States)

    Hofmann, A. F.; Peltzer, E. T.; Brewer, P. G.

    2013-04-01

    Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑ CO2], etc.) as the critical variable and with a major focus on carbonate shell formation. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyse the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T) and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas, since with CO2 the influence of the seawater carbonate acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and fluid flow rate under typical oceanic concentrations. The effect of these reactions can be described by an enhancement factor, similar to that widely used for CO2 invasion at the sea surface. While organisms do need to actively regulate flow over their surface to thin the boundary layer to take up enough O2, this seems to be not necessary to facilitate CO2 efflux. Instead, the main impacts of rising oceanic CO2 will most likely be those associated with classical ocean acidification science. Regionally, as with O2, the combination of T, P and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth.

  4. Kinetic bottlenecks to chemical exchange rates for deep-sea animals – Part 2: Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    A. F. Hofmann

    2013-04-01

    Full Text Available Increased ocean acidification from fossil fuel CO2 invasion, from temperature-driven changes in respiration, and from possible leakage from sub-seabed geologic CO2 disposal has aroused concern over the impacts of elevated CO2 concentrations on marine life. Discussion of these impacts has so far focused only on changes in the oceanic bulk fluid properties (ΔpH, Δ[∑ CO2], etc. as the critical variable and with a major focus on carbonate shell formation. Here we describe the rate problem for animals that must export CO2 at about the same rate at which O2 is consumed. We analyse the basic properties controlling CO2 export within the diffusive boundary layer around marine animals in an ocean changing in temperature (T and CO2 concentration in order to compare the challenges posed by O2 uptake under stress with the equivalent problem of CO2 expulsion. The problem is more complex than that for a non-reactive gas, since with CO2 the influence of the seawater carbonate acid-base system needs to be considered. These reactions significantly facilitate CO2 efflux compared to O2 intake at equal temperature, pressure and fluid flow rate under typical oceanic concentrations. The effect of these reactions can be described by an enhancement factor, similar to that widely used for CO2 invasion at the sea surface. While organisms do need to actively regulate flow over their surface to thin the boundary layer to take up enough O2, this seems to be not necessary to facilitate CO2 efflux. Instead, the main impacts of rising oceanic CO2 will most likely be those associated with classical ocean acidification science. Regionally, as with O2, the combination of T, P and pH/pCO2 creates a zone of maximum CO2 stress at around 1000 m depth.

  5. Phosphorylation of Arabidopsis ubiquitin ligase ATL31 is critical for plant carbon/nitrogen nutrient balance response and controls the stability of 14-3-3 proteins.

    Science.gov (United States)

    Yasuda, Shigetaka; Sato, Takeo; Maekawa, Shugo; Aoyama, Shoki; Fukao, Yoichiro; Yamaguchi, Junji

    2014-05-30

    Ubiquitin ligase plays a fundamental role in regulating multiple cellular events in eukaryotes by fine-tuning the stability and activity of specific target proteins. We have previously shown that ubiquitin ligase ATL31 regulates plant growth in response to nutrient balance between carbon and nitrogen (C/N) in Arabidopsis. Subsequent study demonstrated that ATL31 targets 14-3-3 proteins for ubiquitination and modulates the protein abundance in response to C/N-nutrient status. However, the underlying mechanism for the targeting of ATL31 to 14-3-3 proteins remains unclear. Here, we show that ATL31 interacts with 14-3-3 proteins in a phosphorylation-dependent manner. We identified Thr(209), Ser(247), Ser(270), and Ser(303) as putative 14-3-3 binding sites on ATL31 by motif analysis. Mutation of these Ser/Thr residues to Ala in ATL31 inhibited the interaction with 14-3-3 proteins, as demonstrated by yeast two-hybrid and co-immunoprecipitation analyses. Additionally, we identified in vivo phosphorylation of Thr(209) and Ser(247) on ATL31 by MS analysis. A peptide competition assay showed that the application of synthetic phospho-Thr(209) peptide, but not the corresponding unphosphorylated peptide, suppresses the interaction between ATL31 and 14-3-3 proteins. Moreover, Arabidopsis plants overexpressing mutated ATL31, which could not bind to 14-3-3 proteins, showed accumulation of 14-3-3 proteins and growth arrest in disrupted C/N-nutrient conditions similar to wild-type plants, although overexpression of intact ATL31 resulted in repression of 14-3-3 accumulation and tolerance to the conditions. Together, these results demonstrate that the physiological role of phosphorylation at 14-3-3 binding sites on ATL31 is to modulate the binding ability and stability of 14-3-3 proteins to control plant C/N-nutrient response.

  6. Mitigative effects of spermidine on photosynthesis and carbon-nitrogen balance of cucumber seedlings under Ca(NO3)2 stress.

    Science.gov (United States)

    Du, Jing; Shu, Sheng; Shao, Qiaosai; An, Yahong; Zhou, Heng; Guo, Shirong; Sun, Jin

    2016-01-01

    Ca(NO3)2 stress is one of the most serious constraints to plants production and limits the plants growth and development. Application of polyamines is a convenient and effective approach for enhancing plant salinity tolerance. The present investigation aimed to discover the photosynthetic carbon-nitrogen (C-N) mechanism underlying Ca(NO3)2 stress tolerance by spermidine (Spd) of cucumber (Cucumis sativus L. cv. Jinyou No. 4). Seedling growth and photosynthetic capacity [including net photosynthetic rate (P N), stomatal conductance (Gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr)] were significantly inhibited by Ca(NO3)2 stress (80 mM). However, a leaf-applied Spd (1 mM) treatment alleviated the reduction in growth and photosynthesis in cucumber caused by Ca(NO3)2 stress. Furthermore, the application of exogenous Spd significantly decreased the accumulation of NO3 (-) and NH4 (+) caused by Ca(NO3)2 stress and remarkably increased the activities of N metabolism enzymes simultaneously. In addition, photosynthesis N-use efficiency (PNUE) and free amino acids were significantly enhanced by exogenous Spd in response to Ca(NO3)2 stress, thus promoting the biosynthesis of N containing compounds and soluble protein. Also, the amounts of several carbohydrates (including sucrose, fructose and glucose), total C content and the C/N radio increased significantly in the presence of Spd. Based on our results, we suggest that exogenous Spd could effectively accelerate nitrate transformation into amino acids and improve cucumber plant photosynthesis and C assimilation, thereby enhancing the ability of the plants to maintain their C/N balance, and eventually promote the growth of cucumber plants under Ca(NO3)2 stress.

  7. Cómo resolver un balance de energía CON reacción química - parte 1

    OpenAIRE

    Fernandez-Torres, Maria J.

    2013-01-01

    Ejemplo de cómo encontrar el valor de "incremento de entalpía" para resolver un balance de energía dentro de la disciplina de la Ingeniería Química. Para el cálculo que se presenta se utilizan los valores de entalpías de formación de las sustancias que intervienen en la reacción química.

  8. Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy conversion subsystems and components. Part 3: Gasification, process fuels, and balance of plant

    Science.gov (United States)

    Boothe, W. A.; Corman, J. C.; Johnson, G. G.; Cassel, T. A. V.

    1976-01-01

    Results are presented of an investigation of gasification and clean fuels from coal. Factors discussed include: coal and coal transportation costs; clean liquid and gas fuel process efficiencies and costs; and cost, performance, and environmental intrusion elements of the integrated low-Btu coal gasification system. Cost estimates for the balance-of-plant requirements associated with advanced energy conversion systems utilizing coal or coal-derived fuels are included.

  9. The dynamic balance of the children with cerebral palsy and typical developing during gait. Part I: Spatial relationship between COM and COP trajectories.

    Science.gov (United States)

    Hsue, Bih-Jen; Miller, Freeman; Su, Fong-Chin

    2009-04-01

    Analysis of the COM or COP movement has been a simplified method to illustrate the balance disorders in static stance and gait, but has its limitation when examined alone. Dynamic stability of 32 children with cerebral palsy (CP) was examined and compared with 10 typically developing (TD) children by measuring the displacement of center of mass (COM) and center of pressure (COP) and their spatial relationship. The children with CP were further divided into two groups based on topographical involvement, hemiplegia (Hemi) and diplegia (Di). The participants walked with their preferred speed at least 5 successful trials on a walkway with two force plates mounted in the middle. An eight-camera motion analysis was used to capture 26 reflective markers secured at the bony landmarks of the participant. The data obtained from motion analysis and force plates was used to calculate COM and COP. The results showed either of two CP groups demonstrated significantly greater peak-to-peak COM and COP displacement in medio-lateral (ML) and lower peak-to-peak COM and COP displacement in anterio-posterior (AP) direction than TD group. The root mean square (RMS) of COM-COP divergence of Hemi and Di groups were higher than that of TD group in AP and ML direction, but only the difference in ML direction was significant. Present study demonstrates that COM-COP divergence can characterize the dynamic balance of the CP children in walking, and thus assist in comparing and differentiating balance patterns.

  10. Balancing Acts

    Science.gov (United States)

    ... new type of balance therapy using computerized, virtual reality. UPMC associate professor Susan Whitney, Ph.D., developed ... virtual grocery store in the university's Medical Virtual Reality Center. Patients walk on a treadmill and safely ...

  11. Balance Problems

    Science.gov (United States)

    ... fall may affect an older adult's life. BPPV (Benign Paroxysmal Positional Vertigo) There are many types of balance disorders. One of the most common is benign paroxysmal positional vertigo, or BPPV. In BPPV, you experience a brief, ...

  12. Ultrasonic characterization of defects. Part 4. Study of realistic flaws in welded carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Lingvall, F.; Stepinski, T. [Uppsala Univ. (Sweden). Signals and Systems

    1999-02-01

    This report treats the ultrasonic measurements performed on the new V-welded carbon steel blocks and development of the algorithms for feature extraction, flaw position estimation, etc. Totally 36 different defects, divided into 8 types, were manufactured and implanted into the V-welds in the steel blocks. The flaw population can also be divided in two major groups: sharp flaws (various types of cracks and lack of fusion) and soft types of flaws (slag, porosity and over penetration). A large amount of B- and D-scan measurements were performed on these flaws using 6 different transducers. The evaluation of these measurements resulted in the conclusion that the signal variation for the same type of defects is rather large compared to the variation found in signals from artificial and simulated defects. The steel block measurements also revealed that some of the defects were hard to distinguish, particularly if traditional features like fall/raise times, pulse duration and echo dynamics are used. To overcome this difficulty more powerful feature extraction methods were proposed, like the discrete wavelet transform and principal component analysis. Another important subject that is treated in this report is the estimation of flaw positions from B-scans. The previously used, one dimensional method, appeared to be sensitive to errors in the steel block measurements which, in some cases, resulted in poor flaw position estimates. Therefore, a two dimensional approach was proposed which should result in more robust estimates due to the larger amount of data that is used for the estimation.

  13. Identifying shared and contested elements in climate plans as part of shaping transitions towards a Danish low carbon society

    DEFF Research Database (Denmark)

    Jørgensen, Michael Søgaard

    2011-01-01

    the Danish Society of Engineers, a renewable energy NGO, an environmental NGO and a national climate change commission. The aim is to identify shared and contested elements, which need to be addressed in attempts to establish alignment around transition efforts towards a fossil free Danish society...... in agriculture. The plans differ with respect to whether and how agricultural production and Danish food consumption should change as part of transitions towards a low carbon society. All four plans agree about a significant increase in Danish wind turbine capacity and stronger energy saving efforts in Danish...... production and consumption activities. The plans differ with respect to how big reduction of energy consumption it is possible to obtain and how big the future energy consumption will be. This has implications for how big wind turbine capacity the plans assume is necessary and possible to build, ranging from...

  14. Emission factors of air pollutants from CNG-gasoline bi-fuel vehicles: Part I. Black carbon.

    Science.gov (United States)

    Wang, Yang; Xing, Zhenyu; Xu, Hui; Du, Ke

    2016-12-01

    Compressed natural gas (CNG) is considered to be a "cleaner" fuel compared to other fossil fuels. Therefore, it is used as an alternative fuel in motor vehicles to reduce emissions of air pollutants in transportation. To quantify "how clean" burning CNG is compared to burning gasoline, quantification of pollutant emissions under the same driving conditions for motor vehicles with different fuels is needed. In this study, a fleet of bi-fuel vehicles was selected to measure the emissions of black carbon (BC), carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) for driving in CNG mode and gasoline mode respectively under the same set of constant speeds and accelerations. Comparison of emission factors (EFs) for the vehicles burning CNG and gasoline are discussed. This part of the paper series reports BC EFs for bi-fuel vehicles driving on the real road, which were measured using an in situ method. Our results show that burning CNG will lead to 54%-83% reduction in BC emissions per kilometer, depending on actual driving conditions. These comparisons show that CNG is a cleaner fuel than gasoline for motor vehicles in terms of BC emissions and provide a viable option for reducing BC emissions cause by transportation.

  15. Huella del Carbono. Parte 2: La Visión de las Empresas, los Cuestionamientos y el Futuro Carbon Footprint: Part 2: Enterprises Viewpoint, Doubts and the Future

    Directory of Open Access Journals (Sweden)

    César Espíndola

    2012-01-01

    Full Text Available En esta segunda parte de la serie, se discute sobre la visión y posición que tienen las empresas frente al concepto de Huella del Carbono (HdC y de los métodos para cuantificarla. Se analiza los criterios de clasificación de emisiones en las principales metodologías de cálculo de la HdC y se discute sobre los principales cuestionamientos a la HdC, sobre los temas a resolver y sus alternativas de solución. Se presenta una base comparativa para los cuatro principales métodos de determinación de HdC actualmente vigentes en el mercado y se propone un método denominado Abaco para la contabilización de emisiones de CO2 equivalente , que permite identificar las características comunes de estos métodos. Todo esto puede servir de base en la toma de decisiones gerenciales para adoptar una determinada metodología. Se concluye que d e mantenerse la falta de claridad y comparabilidad en la determinación de emisiones podría provocar la pérdida de una gran oportunidad para lanzar una nueva economía medio-ambientalmente sostenible.In this second part of the series, the viewpoint of the enterprises and their position with respect to the implementation of carbon footprint (CFP quantification. The criteria for classification of emissions and the main methodologies for calculating the CFP are discussed and analyzed. The main questions and doubts about the CFP, on the subjects to be discussed and the alternatives of solution. A comparison of the main four methods currently used for determining the CFP and a method named Abacus for quantifying emissions of equivalent CO2 that allows identifying the common characteristics to all of them. All this can serve as basis for decision-making to adopt a given methodology. It is concluded that if the present situation of confusion of the different approaches to quantify the CFP continues, the companies and governments are loosing a great opportunity to arrive to a new environmentally sustainable economy.

  16. Emulating atmosphere-ocean and carbon cycle models with a simpler model, MAGICC6 – Part 2: Applications

    Directory of Open Access Journals (Sweden)

    M. Meinshausen

    2011-02-01

    Full Text Available Intercomparisons of coupled atmosphere-ocean general circulation models (AOGCMs and carbon cycle models are important for galvanizing our current scientific knowledge to project future climate. Interpreting such intercomparisons faces major challenges, not least because different models have been forced with different sets of forcing agents. Here, we show how an emulation approach with MAGICC6 can address such problems. In a companion paper (Meinshausen et al., 2011a, we show how the lower complexity carbon cycle-climate model MAGICC6 can be calibrated to emulate, with considerable accuracy, globally aggregated characteristics of these more complex models. Building on that, we examine here the Coupled Model Intercomparison Project's Phase 3 results (CMIP3. If forcing agents missed by individual AOGCMs in CMIP3 are considered, this reduces ensemble average temperature change from pre-industrial times to 2100 under SRES A1B by 0.4 °C. Differences in the results from the 1980 to 1999 base period (as reported in IPCC AR4 to 2100 are negligible, however, although there are some differences in the trajectories over the 21st century. In a second part of this study, we consider the new RCP scenarios that are to be investigated under the forthcoming CMIP5 intercomparison for the IPCC Fifth Assessment Report. For the highest scenario, RCP8.5, relative to pre-industrial levels, we project a median warming of around 4.6 °C by 2100 and more than 7 °C by 2300. For the lowest RCP scenario, RCP3-PD, the corresponding warming is around 1.5 °C by 2100, decreasing to around 1.1 °C by 2300 based on our AOGCM and carbon cycle model emulations. Implied cumulative CO2 emissions over the 21st century for RCP8.5 and RCP3-PD are 1881 GtC (1697 to 2034 GtC, 80% uncertainty range and 381 GtC (334 to 488 GtC, when prescribing CO2 concentrations and accounting for uncertainty in the carbon cycle. Lastly, we assess the reasons why a previous MAGICC

  17. The Work-Study Nexus: The Challenges of Balancing Full-Time Business Degree Study with a Part-Time Job

    Science.gov (United States)

    Richardson, Mark; Evans, Carl; Gbadamosi, Gbolahan

    2014-01-01

    This study examined how full-time university students cope with part-time working during term time. A qualitative approach was used to examine how students simultaneously manage the two activities, and how part-time working affects their academic study. Semi-structured interviews were used to obtain data from a sample of 30 undergraduate business…

  18. Modelling ruptures of buried high-pressure dense-phase CO2 pipelines in carbon capture and storage applications - Part II. A full-scale rupture

    OpenAIRE

    Wareing, CJ; Fairweather, M.; Falle, SAEG; Woolley, RM

    2015-01-01

    Carbon capture and storage (CCS) presents a short-term option for significantly reducing the amount of carbon dioxide (CO2) released into the atmosphere. National Grid initiated the COOLTRANS research programme to consider the CCS pipeline transportation of high-pressure dense-phase CO2, including the development and application of a mathematical model for predicting the sonic near-field dispersion of pure CO2 following pipeline venting or failure. In Part I (Wareing et al., 2015a) validation...

  19. The impacts of drainage, nutrient status and management practice on the full carbon balance of grasslands on organic soils in a maritime temperate zone

    Directory of Open Access Journals (Sweden)

    F. Renou-Wilson

    2014-04-01

    Full Text Available Temperate grasslands on organic soils are diverse due to edaphic properties but also to regional management practices and this heterogeneity is reflected in the wide range of greenhouse gas flux values reported in the literature. In Ireland, most grasslands on organic soils were drained several decades ago and are managed as extensive pastures with little or no fertilisation. This study describes a two-year study of the net ecosystem carbon balance (NECB of two such sites. We determined greenhouse gas (GHG fluxes and waterborne carbon emissions in a nutrient rich grassland and compared it with values measured from two nutrient poor organic soils: a deep drained and a shallow drained site. GHG fluxes (CO2, CH4 and N2O were determined using the chamber technique, and fluvial C fluxes were estimated by combining drainage water concentrations and flows. The nutrient rich site was an annual source of CO2 (NEE 233 g C m−2yr−1, CH4 neutral, and a small source of nitrous oxide (1.6 kg N2O-N ha−1yr−1. NEE at the shallow drained site was −89 and −99 g C m−2yr−1 in Years 1 and 2 respectively, and NEE at the deep drained site was +85 and −26 g C m−2yr−1 respectively. Low CH4 emissions (1.3 g C m−2yr−1 were recorded at the shallow drained nutrient poor site. Fluvial exports from the nutrient rich site totalled 69.8 g C m−2yr−1 with 54% as dissolved organic C (DOC. Waterborne C losses from the nutrient poor site reflected differences in annual runoff totalling 44 g C m−2yr−1 in Year 1 and 30.8 g C m−2yr−1 in Year 2. The NECB of the nutrient rich grassland was 663 g C m−2yr−1 with biomass exports being the major component accounting for 53%. The NECB of the nutrient poor deep drained site was less than half of the nutrient rich site (2 year mean 267 g C m−2yr−1. Although NEE at the nutrient poor shallow drained site was negative in both years, high biomass export meant it was a net C source (2 year mean NECB 103 g

  20. Compound-specific carbon and hydrogen isotope analysis of sub-parts per billion level waterborne petroleum hydrocarbons

    Science.gov (United States)

    Wang, Y.; Huang, Y.; Huckins, J.N.; Petty, J.D.

    2004-01-01

    Compound-specific carbon and hydrogen isotope analysis (CSCIA and CSHIA) has been increasingly used to study the source, transport, and bioremediation of organic contaminants such as petroleum hydrocarbons. In natural aquatic systems, dissolved contaminants represent the bioavailable fraction that generally is of the greatest toxicological significance. However, determining the isotopic ratios of waterborne hydrophobic contaminants in natural waters is very challenging because of their extremely low concentrations (often at sub-parts ber billion, or even lower). To acquire sufficient quantities of polycyclic aromatic hydrocarbons with 10 ng/L concentration for CSHIA, more than 1000 L of water must be extracted. Conventional liquid/liquid or solid-phase extraction is not suitable for such large volume extractions. We have developed a new approach that is capable of efficiently sampling sub-parts per billion level waterborne petroleum hydrocarbons for CSIA. We use semipermeable membrane devices (SPMDs) to accumulate hydrophobic contaminants from polluted waters and then recover the compounds in the laboratory for CSIA. In this study, we demonstrate, under a variety of experimental conditions (different concentrations, temperatures, and turbulence levels), that SPMD-associated processes do not induce C and H isotopic fractionations. The applicability of SPMD-CSIA technology to natural systems is further demonstrated by determining the ??13C and ??D values of petroleum hydrocarbons present in the Pawtuxet River, RI. Our results show that the combined SPMD-CSIA is an effective tool to investigate the source and fate of hydrophobic contaminants in the aquatic environments.

  1. Rotary and Magnus balances

    Science.gov (United States)

    Malcolm, G. N.

    1981-01-01

    Two wind tunnel techniques for determining part of the aerodynamic information required to describe the dynamic bahavior of various types of vehicles in flight are described. Force and moment measurements are determined with a rotary-balance apparatus in a coning motion and with a Magnus balance in a high-speed spinning motion. Coning motion is pertinent to both aircraft and missiles, and spinning is important for spin stabilized missiles. Basic principles of both techniques are described, and specific examples of each type of apparatus are presented. Typical experimental results are also discussed.

  2. AANA journal course. Update for nurse anesthetists--part 4--life in the balance: the role of serpins in disease genesis and prevention.

    Science.gov (United States)

    Aker, John; Biddle, Chuck

    2007-10-01

    Complex biological systems are often shaped and maintained by opposing forces. A relevant biological example is the delicate balance between proteases and their inhibitors. Serine proteases contain a serine residue in the active site of the molecule that is essential to the activity of the enzyme. Protease inhibitors limit the activity of proteases in the body. As examples, aprotinin (Trasylol), a serine protease inhibitor, and aminocaproic acid (Amicar), a lysine protease inhibitor, are used to decrease the rate of fibrinolysis and have recently been the subject of considerable controversy in the literature regarding safety and efficacy. This AANA journal course reviews 2 common examples of protease inhibitor disorders, angioedema and a form of emphysema, that are of particular anesthetic relevance.

  3. Black carbon variability since preindustrial times in the eastern part of Europe reconstructed from Mt. Elbrus, Caucasus, ice cores

    Science.gov (United States)

    Lim, Saehee; Faïn, Xavier; Ginot, Patrick; Mikhalenko, Vladimir; Kutuzov, Stanislav; Paris, Jean-Daniel; Kozachek, Anna; Laj, Paolo

    2017-03-01

    Black carbon (BC), emitted by fossil fuel combustion and biomass burning, is the second largest man-made contributor to global warming after carbon dioxide (Bond et al., 2013). However, limited information exists on its past emissions and atmospheric variability. In this study, we present the first high-resolution record of refractory BC (rBC, including mass concentration and size) reconstructed from ice cores drilled at a high-altitude eastern European site in Mt. Elbrus (ELB), Caucasus (5115 m a.s.l.). The ELB ice core record, covering the period 1825-2013, reflects the atmospheric load of rBC particles at the ELB site transported from the European continent with a larger rBC input from sources located in the eastern part of Europe. In the first half of the 20th century, European anthropogenic emissions resulted in a 1.5-fold increase in the ice core rBC mass concentrations with respect to its level in the preindustrial era (before 1850). The summer (winter) rBC mass concentrations increased 5-fold (3.3-fold) in 1960-1980, followed by a decrease until ˜ 2000. Over the last decade, the rBC signal for summertime slightly increased. We have compared the signal with the atmospheric BC load simulated using past BC emissions (ACCMIP and MACCity inventories) and taken into account the contribution of different geographical regions to rBC distribution and deposition at the ELB site. Interestingly, the observed rBC variability in the ELB ice core record since the 1960s is not in perfect agreement with the simulated atmospheric BC load. Similar features between the ice core rBC record and the best scenarios for the atmospheric BC load support anthropogenic BC increase in the 20th century being reflected in the ELB ice core record. However, the peak in BC mass concentration observed in ˜ 1970 in the ice core is estimated to occur a decade later from past inventories. BC emission inventories for the period 1960s-1970s may be underestimating European anthropogenic emissions

  4. ETHICAL AND LEGAL ASPECTS OF INFECTIONS DISEASES AND VACCINATION Part 4. The balance between universal ethical and ecoethics principles on zooanthroponosis

    Directory of Open Access Journals (Sweden)

    O. I. Kubar

    2015-01-01

    Full Text Available The current paper continued the presentation of the data on ethical, legal and social aspects of the problems connected with the study for prevention infections diseases, additionally including the wide list of infections diseases and increasing the specter of ethical problems in the science in comparision with previous publications in this aria. The investigation of the balance universal ethical principles and ecoethics in the field of zooanthroponosis has been done first time in this paper. Data of the paper are based on the scientific and professional experience of the authors both in infections diseases and bioethics and give the analysis of main international UNESCO documents on bioethics and ecoethics. The principal element that has been used by authors for analysis was the view on epidemiology of zooanthroponosis as ecological process for integration between ethiological agents of infections diseases on the real population of different animals including human beings. Such approach became the base for including the biological, social, economical, topographic and environmental factors for investigation the principals of control and prevention in the aria of zooanthroponosis. In the paper has been presented the set of both environmental principles: common and practical. Theoretical picture of the application the philosophical standards of environmental ethics has been done in real conditions of ethiology, patogenics, epidemiology, clinic, treatment and prevention such kinds of zooanthroponosis as: eastern equine encephalitis, tick borne encephalitis, leptospirosis, Q-fever, tularemia, hemolytic uremic syndrome, listeriosis, West Nile fever, pseudo-tuberculosis and others. In the frame of the understanding ideology and principless of environmental ethics such as “respect for all life forms, human and non-human” and “respect for biodiversity” in the practical situation of zooanthroponosis the priority of prevention human being and

  5. Balance (or Vestibular) Rehabilitation

    Science.gov (United States)

    ... the Public / Hearing and Balance Balance (or Vestibular) Rehabilitation Audiologic (hearing), balance, and medical diagnostic tests help ... whether you are a candidate for vestibular (balance) rehabilitation. Vestibular rehabilitation is an individualized balance retraining exercise ...

  6. Stable Isotopes of Carbon Monoxide in an Urban Environment: A Study at Indianapolis, IN as part of the INFLUX Campaign

    Science.gov (United States)

    Vimont, I.; Petrenko, V. V.; Turnbull, J. C.; Place, P.; White, J. W. C.; Karion, A.

    2015-12-01

    We have developed a new system capable of measuring stable isotopes of carbon monoxide (CO) in small atmospheric samples. Measurements at 3 tall tower sites in Indianapolis, IN, USA have been ongoing since July 2013 as part of the INdianapolis FLUX (INFLUX) project. These three towers consist of an upwind, or background site, a site in the urban center, and a site on the downwind edge of the city. The tower collections are discrete, one hour integrated samples taken using NOAA's Portable Flask Package system. These sites have been measured for CO mole fraction, 13CO, and C18O approximately 6 times per month. We present a time series of data from these three sites, as well as a source analysis of the CO produced during the winter months (the winter data allow the use of several simplifying assumptions). We have identified mobile (vehicular) fossil fuel emissions as the only clearly significant wintertime source of CO, and quantified the stable isotopic signature of that source. We also present data from a traffic study done in March of 2015. A vehicle-based collection system was used for this study, and both continuous CO mole fraction and discrete CO mole fraction, 13CO, and C18O measurements were made. The results for CO stable isotopes are consistent with the vehicular emission CO isotopic signatures inferred from the tower samples.

  7. Vibration impact acoustic emission technique for identification and analysis of defects in carbon steel tubes: Part B Cluster analysis

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Zakiah Abd [Universiti Teknikal Malaysia Melaka (Malaysia); Jamaludin, Nordin; Junaidi, Syarif [Faculty of Engineering and Built, Universiti Kebangsaan Malaysia, Bangi (Malaysia); Yahya, Syed Yusainee Syed [Universiti Teknologi MARA, Shah Alam (Malaysia)

    2015-04-15

    Current steel tubes inspection techniques are invasive, and the interpretation and evaluation of inspection results are manually done by skilled personnel. Part A of this work details the methodology involved in the newly developed non-invasive, non-destructive tube inspection technique based on the integration of vibration impact (VI) and acoustic emission (AE) systems known as the vibration impact acoustic emission (VIAE) technique. AE signals have been introduced into a series of ASTM A179 seamless steel tubes using the impact hammer. Specifically, a good steel tube as the reference tube and four steel tubes with through-hole artificial defect at different locations were used in this study. The AEs propagation was captured using a high frequency sensor of AE systems. The present study explores the cluster analysis approach based on autoregressive (AR) coefficients to automatically interpret the AE signals. The results from the cluster analysis were graphically illustrated using a dendrogram that demonstrated the arrangement of the natural clusters of AE signals. The AR algorithm appears to be the more effective method in classifying the AE signals into natural groups. This approach has successfully classified AE signals for quick and confident interpretation of defects in carbon steel tubes.

  8. Carbon, nitrogen, oxygen and sulfide budgets in the Black Sea : a biogeochemical model of the whole water column coupling the oxic and anoxic parts

    NARCIS (Netherlands)

    Grégoire, M.; Soetaert, K.E.R.

    2010-01-01

    Carbon, nitrogen, oxygen and sulfide budgets are derived for the Black Sea water column from a coupled physical–biogeochemical model. The model is applied in the deep part of the sea and simulates processes over the whole water column including the anoxic layer that extends from similar, equals115 m

  9. Balancing priorities

    DEFF Research Database (Denmark)

    Mønsted, Troels; Johansen, Andreas Kaas; Lauridsen, Frederik Vahr Bjarnø

    2016-01-01

    a heterogeneous ensemble of care providers. In this paper, we present findings from a field study of coordinative work in distributed elder care in Denmark. The purpose of this study is to further our understanding of the coordinative challenges of distributed elder care, and to inform design of new care......, that are needed by the healthcare system, but also the work involved in balancing priorities....

  10. Carbon balance for different management practices for fast growing tree species planted on former pastureland in southern Europe: a case study using the CO2 Fix model

    NARCIS (Netherlands)

    Pérez-Crusado, C.; Mohren, G.M.J.; Merino, A.; Rodríguez-Soalleiro, R.

    2012-01-01

    Although it is known that forestry mitigates carbon emissions to some degree, there is still a need to investigate the extent to which changes in forest management regimes affect the carbon cycle. In a climate-change scenario, forest management schemes must be optimized to maximize product supply an

  11. Coupled Climate–Economy–Biosphere (CoCEB model – Part 2: Deforestation control and investment in carbon capture and storage technologies

    Directory of Open Access Journals (Sweden)

    K. B. Z. Ogutu

    2015-04-01

    Full Text Available This study uses the global climate–economy–biosphere (CoCEB model developed in Part 1 to investigate economic aspects of deforestation control and carbon sequestration in forests, as well as the efficiency of carbon capture and storage (CCS technologies as policy measures for climate change mitigation. We assume – as in Part 1 – that replacement of one technology with another occurs in terms of a logistic law, so that the same law also governs the dynamics of reduction in carbon dioxide emission using CCS technologies. In order to take into account the effect of deforestation control, a slightly more complex description of the carbon cycle than in Part 1 is needed. Consequently, we add a biomass equation into the CoCEB model and analyze the ensuing feedbacks and their effects on per capita gross domestic product (GDP growth. Integrating biomass into the CoCEB and applying deforestation control as well as CCS technologies has the following results: (i low investment in CCS contributes to reducing industrial carbon emissions and to increasing GDP, but further investment leads to a smaller reduction in emissions, as well as in the incremental GDP growth; and (ii enhanced deforestation control contributes to a reduction in both deforestation emissions and in atmospheric carbon dioxide concentration, thus reducing the impacts of climate change and contributing to a slight appreciation of GDP growth. This effect is however very small compared to that of low-carbon technologies or CCS. We also find that the result in (i is very sensitive to the formulation of CCS costs, while to the contrary, the results for deforestation control are less sensitive.

  12. Aplikácia Balanced Scorecard

    OpenAIRE

    Kušniráková, Dana

    2012-01-01

    This thesis is focused on creation of system Balanced Scorecard for the company Lekkerland Česká republika s.r.o. The aim of thesis is to create strategy map that illustrates the interdependence four perspectives of the system Balanced Scorecard. In the theoretical part foundations of strategic management and the system of Balanced Scorecard are introduced. The theoretical part is dedicated to introduction of company, its vision and strategy. The parts of thesis are also Porter's and SWOT ana...

  13. Effect of uncertainty in surface mass balance elevation feedback on projections of the future sea level contribution of the Greenland ice sheet – Part 2: Projections

    Directory of Open Access Journals (Sweden)

    A. Quiquet

    2013-02-01

    Full Text Available We apply a new parameterisation of the Greenland ice sheet (GrIS feedback between surface mass balance (SMB: the sum of surface accumulation and surface ablation and surface elevation in the MAR regional climate model (Edwards et al., 2013 to projections of future climate change using five ice sheet models (ISMs. The MAR climate projections are for 2000–2199, forced by the ECHAM5 and HadCM3 global climate models (GCMs under the SRES A1B emissions scenario. The additional sea level contribution due to the SMB-elevation feedback averaged over five ISM projections for ECHAM5 and three for HadCM3 is 4.3% (best estimate; 95% credibility interval 1.8–6.9% at 2100, and 9.6% (best estimate; 95% credibility interval 3.6–16.0% at 2200. In all results the elevation feedback is significantly positive, amplifying the GrIS sea level contribution relative to the MAR projections in which the ice sheet topography is fixed: the lower bounds of our 95% credibility intervals (CIs for sea level contributions are larger than the "no feedback" case for all ISMs and GCMs. Our method is novel in sea level projections because we propagate three types of modelling uncertainty – GCM and ISM structural uncertainties, and elevation feedback parameterisation uncertainty – along the causal chain, from SRES scenario to sea level, within a coherent experimental design and statistical framework. The relative contributions to uncertainty depend on the timescale of interest. At 2100, the GCM uncertainty is largest, but by 2200 both the ISM and parameterisation uncertainties are larger. We also perform a~perturbed parameter ensemble with one ISM to estimate the shape of the projected sea level probability distribution; our results indicates that the probability density is slightly skewed towards higher sea level contributions.

  14. Short period forecasting of catchment-scale precipitation. Part II: a water-balance storm model for short-term rainfall and flood forecasting

    Directory of Open Access Journals (Sweden)

    V. A. Bell

    2000-01-01

    Full Text Available A simple two-dimensional rainfall model, based on advection and conservation of mass in a vertical cloud column, is investigated for use in short-term rainfall and flood forecasting at the catchment scale under UK conditions. The model is capable of assimilating weather radar, satellite infra-red and surface weather observations, together with forecasts from a mesoscale numerical weather prediction model, to obtain frequently updated forecasts of rainfall fields. Such data assimilation helps compensate for the simplified model dynamics and, taken together, provides a practical real-time forecasting scheme for catchment scale applications. Various ways are explored for using information from a numerical weather prediction model (16.8 km grid within the higher resolution model (5 km grid. A number of model variants is considered, ranging from simple persistence and advection methods used as a baseline, to different forms of the dynamic rainfall model. Model performance is assessed using data from the Wardon Hill radar in Dorset for two convective events, on 10 June 1993 and 16 July 1995, when thunderstorms occurred over southern Britain. The results show that (i a simple advection-type forecast may be improved upon by using multiscan radar data in place of data from the lowest scan, and (ii advected, steady-state predictions from the dynamic model, using 'inferred updraughts', provides the best performance overall. Updraught velocity is inferred at the forecast origin from the last two radar fields, using the mass-balance equation and associated data and is held constant over the forecast period. This inference model proves superior to the buoyancy parameterisation of updraught employed in the original formulation. A selection of the different rainfall forecasts is used as input to a catchment flow forecasting model, the IH PDM (Probability Distributed Moisture model, to assess their effect on flow forecast accuracy for the 135 km2 Brue catchment

  15. Radiocarbon dating of dissolved inorganic carbon in groundwater from confined parts of the Upper Floridan aquifer, Florida, USA

    Science.gov (United States)

    Plummer, Niel; Sprinkle, Craig

    2001-03-01

    Geochemical reaction models were evaluated to improve radiocarbon dating of dissolved inorganic carbon (DIC) in groundwater from confined parts of the Upper Floridan aquifer in central and northeastern Florida, USA. The predominant geochemical reactions affecting the 14C activity of DIC include (1) dissolution of dolomite and anhydrite with calcite precipitation (dedolomitization), (2) sulfate reduction accompanying microbial degradation of organic carbon, (3) recrystallization of calcite (isotopic exchange), and (4) mixing of fresh water with as much as 7% saline water in some coastal areas. The calculated cumulative net mineral transfers are negligibly small in upgradient parts of the aquifer and increase significantly in downgradient parts of the aquifer, reflecting, at least in part, upward leakage from the Lower Floridan aquifer and circulation that contacted middle confining units in the Floridan aquifer system. The adjusted radiocarbon ages are independent of flow path and represent travel times of water from the recharge area to the sample point in the aquifer. Downgradient from Polk City (adjusted age 1.7 ka) and Keystone Heights (adjusted age 0.4 ka), 14 of the 22 waters have adjusted 14C ages of 20-30 ka, indicating that most of the fresh-water resource in the Upper Floridan aquifer today was recharged during the last glacial period. All of the paleowaters are enriched in 18O and 2H relative to modern infiltration, with maximum enrichment in δ18O of approximately 2.0‰. Résumé. Les modèles de réactions géochimiques ont été évalués afin de tester la datation par le radiocarbone du carbone minéral dissous (CMD) des eaux souterraines dans les parties captives de la nappe supérieure de Floride, en Floride centrale et nord-orientale (États-Unis). Les réactions géochimiques prédominantes affectant l'activité en 14C du CMD comprennent (1) la dissolution de la dolomite et de l'anhydrite accompagnée de la précipitation de la calcite (d

  16. Molecular properties and intermolecular forces--factors balancing the effect of carbon surface chemistry in adsorption of organics from dilute aqueous solutions.

    Science.gov (United States)

    Terzyk, Artur P

    2004-07-01

    Presented paper recapitulates the results of 6 years' study concerning the effect of carbon surface chemical composition on adsorption of paracetamol, phenol, acetanilide, and aniline from dilute aqueous solutions on carbons. Adsorption-desorption isotherms, enthalpy, and kinetics of adsorption data are shown for the measurements performed at three temperatures (300, 310, and 320 K) at two pH levels (1.5 and 7) on commercial activated carbons. The data were obtained for four carbons: the initial carbon D43/1 and forms modified by applying concentrated HNO3, fuming H2SO4, and gaseous NH3. The modification procedures do not change the porosity in a drastic way, but lead to drastic changes of the composition of carbon surface layer. By applying MOPAC (a general-purpose semiempirical molecular orbital package), the physicochemical constants characterizing the molecules of adsorbates are calculated, including the distribution of the Mulliken charges, the dipole moments and ionization potentials, and the energies of interaction with the unique positive and negative charges. They are correlated with the parameters characterizing the adsorption (and kinetics) process of studied molecules on the mentioned above carbons. The mechanisms proposed in the literature for the description of adsorption from dilute aqueous solutions are verified, and a general mechanism of adsorption is proposed.

  17. Foreseen hydrological changes drive efforts to formulate water balance improvement measures as part of the management options of adaptation at Lake Balaton, Hungary

    Science.gov (United States)

    Molnar, Gabor; Kutics, Karoly

    2013-04-01

    completed with a similar methodology applied in partner lakes of the EULAKES project. Based on the assessment through a participatory process involving a broad group of stakeholders the possible management options were gathered and tested as the alternatives to improve the water balance of the lake.

  18. Social Balance Theory

    OpenAIRE

    Hokky Situngkir; Deni Khanafiah

    2004-01-01

    We construct a model based on social balance theory proposed by Fritz Heider to analyze the interpersonal network among social agents. The model of social balance theory provides us an interesting tool to see how a social group evolves to the possible balance state. We introduce the balance index that can be used to measure social balance in macro structure level (global balance index) or in micro structure (local balance index) to see how the local balance index influences the global balance...

  19. Integrating Remote Sensing, Field Observations, and Models to Understand Disturbance and Climate Effects on the Carbon Balance of the West Coast U.S., Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Beverly E. Law

    2011-10-05

    As an element of NACP research, the proposed investigation is a two pronged approach that derives and evaluates a regional carbon (C) budget for Oregon, Washington, and California. Objectives are (1) Use multiple data sources, including AmeriFlux data, inventories, and multispectral remote sensing data to investigate trends in carbon storage and exchanges of CO2 and water with variation in climate and disturbance history; (2) Develop and apply regional modeling that relies on these multiple data sources to reduce uncertainty in spatial estimates of carbon storage and NEP, and relative contributions of terrestrial ecosystems and anthropogenic emissions to atmospheric CO2 in the region; (3) Model terrestrial carbon processes across the region, using the Biome-BGC terrestrial ecosystem model, and an atmospheric inverse modeling approach to estimate variation in rate and timing of terrestrial uptake and feedbacks to the atmosphere in response to climate and disturbance.

  20. Integrating Remote Sensing, Field Observations, and Models to Understand Disturbance and Climate Effects on the Carbon Balance of the West Coast U.S.

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, Warren [USDA Forest Service

    2014-07-03

    As an element of NACP research, the proposed investigation is a two pronged approach that derives and evaluates a regional carbon (C) budget for Oregon, Washington, and California. Objectives are (1) Use multiple data sources, including AmeriFlux data, inventories, and multispectral remote sensing data to investigate trends in carbon storage and exchanges of CO2 and water with variation in climate and disturbance history; (2) Develop and apply regional modeling that relies on these multiple data sources to reduce uncertainty in spatial estimates of carbon storage and NEP, and relative contributions of terrestrial ecosystems and anthropogenic emissions to atmospheric CO2 in the region; (3) Model terrestrial carbon processes across the region, using the Biome-BGC terrestrial ecosystem model, and an atmospheric inverse modeling approach to estimate variation in rate and timing of terrestrial uptake and feedbacks to the atmosphere in response to climate and disturbance.

  1. Alternative methodology for assessing part-through-wall cracks in carbon steel bends removed from Point Lepreau Generating Station

    Energy Technology Data Exchange (ETDEWEB)

    Duan Xinjian, E-mail: duanx@aecl.c [Senior Engineer, Reactor Engineering Department, Atomic Energy of Canada Ltd., Mississauga, ON (Canada); Kozluk, Michael J., E-mail: kozlukm@aecl.c [Independent Consultant, Oakville, ON (Canada); Gendron, Tracy [Manager-HTS Materials Integrity, Atomic Energy of Canada Ltd., Chalk River, ON (Canada); Slade, John [Senior Technical Advisor, Point Lepreau Generating Station, Lepreau, NB (Canada)

    2011-03-15

    In 2008 April Point Lepreau Generating Station entered an extended refurbishment outage that will involve the replacement of key reactor components (fuel channels and connecting feeder pipes). Prior to the refurbishment outage, New Brunswick Power Nuclear had been successfully managing intergranular, axial cracking of carbon steel feeder piping, that were also experiencing thinning, in the Point Lepreau Generating Station, primarily by an aggressive program of inspection, repair and testing of ex-service material. For the previous three maintenance outages, a probabilistic safety evaluation (PSE) had been used to demonstrate that annual inspection of the highest risk locations maintains the nuclear safety risk from cracking at an acceptably low level. The PSE makes use of the Failure Assessment Diagram (FAD) model to predict the failure of part-through-wall cracks. Burst-pressure testing of two ex-service feeder pipe sections with part-through-wall cracks showed that this FAD model significantly under predicts the failure pressure measured in the component tests. Use of this FAD model introduces undesirable conservatism into PSE assessments that are used to optimize feeder piping inspection and maintenance plans. This paper describes an alternative finite element approach, which could be used to provide more representative structural models for use in PSE assessments. This alternative approach employs the elasto-plastic large strain finite element formulation; uses representative material properties; considers the spatial microstructural distribution; accounts for the effect of work hardening rate; models all deformation processes, i.e., uniform deformation, localized necking, and failure imitation and propagation. Excellent pre-test prediction was shown for the burst-pressure test performed in 2006. Although cold-worked feeder bends have reduced fracture toughness compared to the parent straight pipe, post-test metallurgical examinations showed that failure at the

  2. Storage/Turnover rate of inorganic carbon and its dissolvable part in the profile of saline/alkaline soils.

    Science.gov (United States)

    Wang, Yugang; Wang, Zhongyuan; Li, Yan

    2013-01-01

    Soil inorganic carbon is the most common form of carbon in arid and semiarid regions, and has a very long turnover time. However, little is known about dissolved inorganic carbon storage and its turnover time in these soils. With 81 soil samples taken from 6 profiles in the southern Gurbantongute Desert, China, we investigated the soil inorganic carbon (SIC) and the soil dissolved inorganic carbon (SDIC) in whole profiles of saline and alkaline soils by analyzing their contents and ages with radiocarbon dating. The results showed that there is considerable SDIC content in SIC, and the variations of SDIC and SIC contents in the saline soil profile were much larger than that in the alkaline profile. SDIC storage accounted for more than 20% of SIC storage, indicating that more than 1/5 of the inorganic carbon in both saline and alkaline soil is not in non-leachable forms. Deep layer soil contains considerable inorganic carbon, with more than 80% of the soil carbon stored below 1 m, whether for SDIC or SIC. More importantly, SDIC ages were much younger than SIC in both saline soil and alkaline soil. The input rate of SDIC and SIC ranged from 7.58 to 29.54 g C m(-2) yr(-1) and 1.34 to 5.33 g C m(-2) yr(-1) respectively for saline soil, and from 1.43 to 4.9 g C m(-2) yr(-1) and 0.79 to 1.27 g C m(-2) yr(-1)respectively for alkaline soil. The comparison of SDIC and SIC residence time showed that using soil inorganic carbon to estimate soil carbon turnover would obscure an important fraction that contributes to the modern carbon cycle: namely the shorter residence and higher input rate of SDIC. This is especially true for SDIC in deep layers of the soil profile.

  3. Watt and joule balances

    Science.gov (United States)

    Robinson, Ian A.

    2014-04-01

    time of the weighing and at the centre of gravity of the mass. The paper by Liard and his co-authors at NRC describes how they have made this essential measurement. The accuracy of the watt balance may also depend on the alignment of the apparatus. Two papers deal with this important issue. The first, by Sanchez and his co-authors at NRC, shows that their balance is insensitive to a range of alignments and concentrates on the essential alignments that contribute directly to the overall uncertainty of the apparatus. Thomas and his co-authors at LNE describe their technique for reducing uncertainties in their watt balance by aligning its coil in the field of the magnet to minimize both horizontal forces and torques about horizontal axes. The search for discrepancies between the results from watt balances has encouraged researchers to consider possible error mechanisms arising from the secondary electrical interactions between the coil of a watt balance and other parts of the apparatus. Researchers from INRIM have two such papers: one considering magnetic interactions and the other considering electrostatic interactions. It is essential that such investigations are carried out: both to prove that the problems are understood and for the guidance of those building the next generation of watt and joule balances. The next four papers describe aspects of the construction of watt balances. The BIPM watt balance group describe the principles behind their simultaneous measurement scheme for a watt balance. The balance that they are constructing can also be used in the conventional two-phase mode and their paper describes the relative advantages and disadvantages of the two modes of operation. In a watt balance there are some advantages to precise vertical movement of the coil. The METAS group describe the two mechanisms that they have tested to achieve such motion and give the reasons for the choice of mechanism for use in the balance that they are constructing. The KRISS watt

  4. Balancing Patient Access to Fetoscopic Laser Photocoagulation for Twin-to-Twin Transfusion Syndrome With Maintaining Procedural Competence: Are Collaborative Services Part of the Solution?

    Science.gov (United States)

    Edwards, Andrew G; Teoh, Mark; Hodges, Ryan J; Palma-Dias, Ricardo; Cole, Stephen A; Fung, Alison M; Walker, Susan P

    2016-06-01

    The benefits of fetoscopic laser photocoagulation (FLP) for treatment of twin-to-twin transfusion syndrome (TTTS) have been recognized for over a decade, yet access to FLP remains limited in many settings. This means at a population level, the potential benefits of FLP for TTTS are far from being fully realized. In part, this is because there are many centers where the case volume is relatively low. This creates an inevitable tension; on one hand, wanting FLP to be readily accessible to all women who may need it, yet on the other, needing to ensure that a high degree of procedural competence is maintained. Some of the solutions to these apparently competing priorities may be found in novel training solutions to achieve, and maintain, procedural proficiency, and with the increased utilization of 'competence based' assessment and credentialing frameworks. We suggest an under-utilized approach is the development of collaborative surgical services, where pooling of personnel and resources can improve timely access to surgery, improve standardized assessment and management of TTTS, minimize the impact of the surgical learning curve, and facilitate audit, education, and research. When deciding which centers should offer laser for TTTS and how we decide, we propose some solutions from a collaborative model.

  5. Benefits and risks of fish consumption Part II. RIBEPEIX, a computer program to optimize the balance between the intake of omega-3 fatty acids and chemical contaminants.

    Science.gov (United States)

    Domingo, José L; Bocio, Ana; Martí-Cid, Roser; Llobet, Juan M

    2007-02-12

    In recent years, and based on the importance of fish as a part of a healthy diet, there has been a notable promotion of fish and seafood consumption. However, a number of recent studies have shown that fish may be a potential source of exposure to chemical pollutants, some of them with well known adverse effects on human health. Recently, we determined in 14 edible marine species the concentrations of eicosapentaenoic acid (EPA) and docosohexaenoic acid (DHA), as well as those of a number of chemical contaminants: Cd, Hg, Pb, polychlorinated dibenzo-p-dioxins and furans, polychlorinated biphenyls, hexachlorobenzene, polycyclic aromatic hydrocarbons, polychlorinated naphthalenes, polybrominated diphenylethers and polychlorinated diphenylethers. To quantitative establish the intake of these pollutants (risks) versus that of EPA+DHA (benefits), we designed a simple computer program, RIBEPEIX. The concentrations of EPA, DHA, and the chemical pollutants were introduced into the program. We here present how RIBEPEIX may be used as an easy tool to optimize fish consumption: most suitable species, frequency of consumption, and size of meals. RIBEPEIX can be useful not only for professionals (cardiologists, general physicians, nutritionists, toxicologists, etc.), but also for the general population. It is available at: .

  6. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance.

    Science.gov (United States)

    Rafiq, Muhammad Khalid; Bachmann, Robert Thomas; Rafiq, Muhammad Tariq; Shang, Zhanhuan; Joseph, Stephen; Long, Ruijun

    2016-01-01

    This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13) demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario.

  7. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L. Biochar and Feasibility for Carbon Capture and Energy Balance.

    Directory of Open Access Journals (Sweden)

    Muhammad Khalid Rafiq

    Full Text Available This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13. Higher heating value (HHV of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13 demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario.

  8. Influence of Pyrolysis Temperature on Physico-Chemical Properties of Corn Stover (Zea mays L.) Biochar and Feasibility for Carbon Capture and Energy Balance

    Science.gov (United States)

    Rafiq, Muhammad Khalid; Bachmann, Robert Thomas; Rafiq, Muhammad Tariq; Shang, Zhanhuan; Joseph, Stephen; Long, Ruijun

    2016-01-01

    This study examined the influence of pyrolysis temperature on biochar characteristics and evaluated its suitability for carbon capture and energy production. Biochar was produced from corn stover using slow pyrolysis at 300, 400 and 500°C and 2 hrs holding time. The experimental biochars were characterized by elemental analysis, BET, FTIR, TGA/DTA, NMR (C-13). Higher heating value (HHV) of feedstock and biochars was measured using bomb calorimeter. Results show that carbon content of corn stover biochar increased from 45.5% to 64.5%, with increasing pyrolysis temperatures. A decrease in H:C and O:C ratios as well as volatile matter, coupled with increase in the concentration of aromatic carbon in the biochar as determined by FTIR and NMR (C-13) demonstrates a higher biochar carbon stability at 500°C. It was estimated that corn stover pyrolysed at 500°C could provide of 10.12 MJ/kg thermal energy. Pyrolysis is therefore a potential technology with its carbon-negative, energy positive and soil amendment benefits thus creating win- win scenario. PMID:27327870

  9. Description, calibration and sensitivity analysis of the local ecosystem submodel of a global model of carbon and nitrogen cycling and the water balance in the terrestrial biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kercher, J.R. [Lawrence Livermore National Lab., CA (United States); Chambers, J.Q. [Lawrence Livermore National Lab., CA (United States)]|[California Univ., Santa Barbara, CA (United States). Dept. of Biological Sciences

    1995-10-01

    We have developed a geographically-distributed ecosystem model for the carbon, nitrogen, and water dynamics of the terrestrial biosphere TERRA. The local ecosystem model of TERRA consists of coupled, modified versions of TEM and DAYTRANS. The ecosystem model in each grid cell calculates water fluxes of evaporation, transpiration, and runoff; carbon fluxes of gross primary productivity, litterfall, and plant and soil respiration; and nitrogen fluxes of vegetation uptake, litterfall, mineralization, immobilization, and system loss. The state variables are soil water content; carbon in live vegetation; carbon in soil; nitrogen in live vegetation; organic nitrogen in soil and fitter; available inorganic nitrogen aggregating nitrites, nitrates, and ammonia; and a variable for allocation. Carbon and nitrogen dynamics are calibrated to specific sites in 17 vegetation types. Eight parameters are determined during calibration for each of the 17 vegetation types. At calibration, the annual average values of carbon in vegetation C, show site differences that derive from the vegetation-type specific parameters and intersite variation in climate and soils. From calibration, we recover the average C{sub v} of forests, woodlands, savannas, grasslands, shrublands, and tundra that were used to develop the model initially. The timing of the phases of the annual variation is driven by temperature and light in the high latitude and moist temperate zones. The dry temperate zones are driven by temperature, precipitation, and light. In the tropics, precipitation is the key variable in annual variation. The seasonal responses are even more clearly demonstrated in net primary production and show the same controlling factors.

  10. Bottom-up assessment of the Net Ecosystem Carbon Balance of Russian forests in 2010 for comparison to Top-down estimates.

    Science.gov (United States)

    Maksyutov, S. S.; Shvidenko, A.; Shchepashchenko, D.

    2014-12-01

    The verified full carbon assessment of Russian forests (FCA) is based on an Integrated Land Information System (ILIS) that includes a multi-layer and multi-scale GIS with basic resolution of 1 km and corresponding attributive databases. The ILIS aggregates all available information about ecosystems and landscapes, sets of empirical and semi-empirical data and aggregations, data of different inventories and surveys, and multi-sensor remote sensing data. The ILIS serves as an information base for application of the landscape-ecosystem approach (LEA) of the FCA and as a systems design for comparison and mutual constraints with other methods of study of carbon cycling of forest ecosystems (eddy covariance; process models; inverse modeling; and multi-sensor application of remote sensing). The LEA is based on a complimentary use of the flux-based method with some elements of the pool-based method. Introduction of climatic parameters of individual years in the LEA, as well as some process-based elements, allows providing a substantial decrease of the uncertainties of carbon cycling yearly indicators of forest ecosystems. Major carbon pools (live biomass, coarse woody debris, soil organic carbon) are estimated based on data on areas, distribution and major biometric characteristics of Russian forests presented in form of the ILIS for the country. The major fluxes accounted for include Net Primary Production (NPP), Soil Heterotrophic Respiration (SHR), as well as fluxes caused by decomposition of Coarse Woody Debris (CWD), harvest and use of forest products, fluxes caused by natural disturbances (fire, insect outbreaks, impacts of unfavorable environment) and lateral fluxes to hydrosphere and lithosphere. Use of landscape-ecosystem approach resulted in the NECB at 573±140 Tg C yr-1 (CI 0.9). While the total carbon sink is high, large forest areas, particularly on permafrost, serve as a carbon source. The ratio between net primary production and soil heterotrophic

  11. Computational modeling of elastic properties of carbon nanotube/polymer composites with interphase regions. Part I: Micro-structural characterization and geometric modeling

    KAUST Repository

    Han, Fei

    2014-01-01

    A computational strategy to predict the elastic properties of carbon nanotube-reinforced polymer composites is proposed in this two-part paper. In Part I, the micro-structural characteristics of these nano-composites are discerned. These characteristics include networks/agglomerations of carbon nanotubes and thick polymer interphase regions between the nanotubes and the surrounding matrix. An algorithm is presented to construct three-dimensional geometric models with large amounts of randomly dispersed and aggregated nanotubes. The effects of the distribution of the nanotubes and the thickness of the interphase regions on the concentration of the interphase regions are demonstrated with numerical results. © 2013 Elsevier B.V. All rights reserved.

  12. The 2013 social balance sheet

    OpenAIRE

    Pierrette Heuse

    2014-01-01

    The transposition into national law of Directive 2013/34/EU on the annual financial statements of companies, expected by no later than July 2015, could alter the statistical obligations on small firms in connection with the filing of their annual accounts. In any case, the social balance sheet can no longer form an integral part of their accounts. Nevertheless, it contains original information whose usefulness is highlighted, on the basis of the social balance sheets for 2012, by examining th...

  13. Temperature, salinity, nutrients, carbon, and other profile data collected worldwide as part of the CARINA project (NODC Accession 0057766)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The CARINA (CARbon dioxide IN the Atlantic Ocean) data synthesis project is an international collaborative effort of the EU IP CARBOOCEAN, and US partners. It has...

  14. Intelligent Material Systems and Structures (IMSS). Part 5: Fiber optic registration of deformation in carbon laminates 91/92

    Science.gov (United States)

    Oedman, Svante; Bengtsson, Jan-Peter; Danilsons, Markus; Dickman, Ola; Gruffman, Stig; Lindersson, Kjell; Tanriverdi, Timor

    1993-02-01

    Mechanical deformations induced by stretching optical fibers and epoxy-carbon laminates with embedded optical fibers were studied with fiber optic measurement technology: intensity measurements, reflectometry, and interferometry. The results from the measurements were compared in order to judge which method could be further developed for strain measurement in a laboratory. The conclusion is that the interferometry can be developed into a laboratory method for measuring deformations in carbon laminates.

  15. Dry and wet atmospheric deposition of organic carbon in coastal and water areas of the northeastern part of the Sea of Azov

    Science.gov (United States)

    Sorokina, V. V.; Soier, V. G.

    2016-09-01

    The paper reports on new data focusing on organic carbon contained in aeolian material and precipitation falling on coastal and water areas of the northeastern part of the Sea of Azov. Atmospheric deposition was sampled in 2006-2014. The particulate organic carbon content varied from 4 to 27% in aeolian dust samples. The concentration of the organic carbon dissolved in rainwater was from 1.6 to 4.3 mg C/L, and from 0.9 to 16.6 mg C/L in snow. The particulate organic carbon content varied from 2 to 43% in snow. Intensity of aeolian dust settling decreased from 178 to 33 mg/m2 per day with distance from a source of dust; in contrast, the relative content of organic matter increased. In a spring-summer season the aeolian organic carbon fluxes varied from 12 to 18 mg C/m2 per day in Rostov-on-Don, from 28 to 48 mg C/m2 per day on the Gulf of Taganrog coast, and from 20 to 80 mg C/m2 per day in the water area of the Gulf of Taganrog.

  16. Signature Balancing

    NARCIS (Netherlands)

    Noordkamp, H.W.; Brink, M. van den

    2006-01-01

    Signatures are an important part of the design of a ship. In an ideal situation, signatures must be as low as possible. However, due to budget constraints it is most unlikely to reach this ideal situation. The arising question is which levels of signatures are optimal given the different scenarios i

  17. Research on Carbon Balance of Different Grazing Systems in Stipa breviflora Desert Steppe%不同放牧制度下短花针茅荒漠草原碳平衡研究

    Institute of Scientific and Technical Information of China (English)

    侯向阳; 徐海红

    2011-01-01

    [目的]从碳平衡的角度为确定荒漠草原合理的放牧管理方式提供依据.[方法]采用野外调查法测定生物量季节动态,密闭气室法测定土壤呼吸动态.[结果](1)相较于自由放牧,划区轮牧能保持较高的凋落物量、家畜采食量以及地下生物量,在恢复地上植被方面无明显差别,禁牧保持较高的地上生物量、凋落物量及地下生物量;(2)随着放牧的进行和季节水热条件的变化,土壤呼吸呈现不同的变化趋势,自由放牧在于旱季节产生较小的土壤呼吸;(3)生长季内划区轮牧、自由放牧和围栏禁牧下的荒漠草原净生态系统生产力分别为413.78、401.45和416.80 gC·m·a.[结论]短花针茅荒漠草原生态系统碳收支表现为碳汇,不同放牧制度对碳收支影响较小,相对而言,划区轮牧较自由放牧有微弱的碳积累优势.%[Objective] Taking Stipa breviflora desert steppe in Inner Mongolia as the research object, carbon input, carbon output and carbon balance features in plots that affected by fencing, rotational grazing and continuous grazing for ten years (1999-2009) were determined. [Method] Using field investigation and enclosed chamber method (IRGA), the dynamics of biomass and soil respiration rate were determined in Stipa breviflora desert steppe. The effects of grazing systems on carbon input, carbon output and carbon balance was studied in this paper. [Result] Compared with continuous grazing, the litter fall, livestock feed intake and below-ground biomass were increased by rotational grazing, while no significant difference the community above-ground biomass was found in between continuous grazing and rotational grazing. Litter fall, above ground and below ground biomass were increased by non-grazing. Compared with continuous grazing, rotational grazing and non-grazing increased the soil respiration rate in dry months. Stipa breviflora desert steppe emerged to be carbon sinks under different grazing

  18. Soil Carbon Balance in a Native Temperate Grassland in the Xilin RiverBasin of Inner Mongolia%锡林河流域一个原生草原群落的碳素平衡研究

    Institute of Scientific and Technical Information of China (English)

    李凌浩; 李鑫; 宋世环; 韩兴国; 王其兵; 白文明; 白永飞; 闫志丹; 陈全胜; 张焱; 杨晶

    2002-01-01

    野外调查与历史资料相结合,对内蒙古锡林河流域一个永久试验样地内的羊草( Leymus chinensis (Trin.) Tzvel.)草原群落(原生草原群落)的碳素贮量、主要流量和周转速度等进行了估计.结果表明:1)该群落中地上部净初级生产的碳素固定量的多年平均值为79.8 g C*m-2*a-1,根系碳素输入量的多年平均值为311.9 g C*m-2*a-1,碳素输入总量为391.7 g C*m-2*a-1; 2)土壤净呼吸量为346.9 g C*m-2*a-1,动物(昆虫)采食量14.7 g C*m-2*a-1,地上立枯阶段的淋溶与光化学分解损失为3.2 g C*m-2*a-1,碳素输出总量为364.8 g C*m-2*a-1; 3)该群落中碳素输入略大于输出,净积累速率为26.9 g C*m-2*a-1,0-30 cm土壤中的碳素周转速率为6.2%,周转时间为16年.%Based on historical data and field investigation,some major fluxes and reserves of carbon were estimated,and a tentative analysis of the soil carbon balance was made in a native grassland community in the Xilin River basin of Inner Mongolia.Major results were reported as follows:1) Annual average carbon input from above-ground biomass production was 79.8 g C*m-2*a-1,and from root biomass to 30 cm depth averaged 311.9 g C*m-2*a-1.The summed mean annual carbon input of shoot and root materials in the study site was approximately 391.7 g C*m-2*a-1.2) The annual amount of above-ground biomass consumed by insects averaged 14.7 g C*m-2*a-1,and the carbon output by leaching or light-chemical oxidation was 3.2 g C*m-2*a-1.The annual evolution rate of CO2 from net soil respiration averaged 346.9 g C*m-2*a-1,and the summed mean annual output was approximately 364.8 g C*m-2*a-1.3) A mature,steady-state system could be assumed for the community for which growth and decay were approximately in balance,with a net carbon accumulation of about 26.9 g C*m-2*a-1.Based on the soil organic carbon density of the field,the turnover rate of soil carbon in 0-30 cm depth was calculated to be 6.2%,with a turnover time of 16 years.

  19. [Variation of forest vegetation carbon storage and carbon sequestration rate in Liaoning Province, Northeast China].

    Science.gov (United States)

    Zhen, Wei; Huang, Mei; Zhai, Yin-Li; Chen, Ke; Gong, Ya-Zhen

    2014-05-01

    The forest vegetation carbon stock and carbon sequestration rate in Liaoning Province, Northeast China, were predicted by using Canadian carbon balance model (CBM-CFS3) combining with the forest resource data. The future spatio-temporal distribution and trends of vegetation carbon storage, carbon density and carbon sequestration rate were projected, based on the two scenarios, i. e. with or without afforestation. The result suggested that the total forest vegetation carbon storage and carbon density in Liaoning Province in 2005 were 133.94 Tg and 25.08 t x hm(-2), respectively. The vegetation carbon storage in Quercus was the biggest, while in Robinia pseudoacacia was the least. Both Larix olgensis and broad-leaved forests had higher vegetation carbon densities than others, and the vegetation carbon densities of Pinus tabuliformis, Quercus and Robinia pseudoacacia were close to each other. The spatial distribution of forest vegetation carbon density in Liaoning Province showed a decrease trend from east to west. In the eastern forest area, the future increase of vegetation carbon density would be smaller than those in the northern forest area, because most of the forests in the former part were matured or over matured, while most of the forests in the later part were young. Under the scenario of no afforestation, the future increment of total forest vegetation carbon stock in Liaoning Province would increase gradually, and the total carbon sequestration rate would decrease, while they would both increase significantly under the afforestation scenario. Therefore, afforestation plays an important role in increasing vegetation carbon storage, carbon density and carbon sequestration rate.

  20. Electrochemical oxidation of carbon monoxide: from platinum single crystals to low temperature fuel cells catalysts. Part I: Carbon monoxide oxidation onto low index platinum single crystals

    Directory of Open Access Journals (Sweden)

    PHILIP N. ROSS JR

    2001-12-01

    Full Text Available The electrochemical oxidation of carbon monoxide and the interfacial structure of the CO adlayer (COads on platinum low index single crystals, Pt(111, Pt(100 and two reconstruction of Pt(110, were examined using the rotation disk electrode method in combination with the in situ surface X-ray diffraction scattering technique. The mechanism of CO oxidation is discussed on the basis of the findings that, depending on the potential, two energetic states of COads exist on the platinum surfaces. Thus, at lower potentials, weakly bonded states (COads,w and at higher potentials strongly bonded states (COads,s are formed. The mechanism of the oxidation of hydrogen-carbon monoxide mixtures is also proposed.

  1. Spatial and temporal patterns of biotic exchanges of CO{sub 2} between the atmosphere and tropical landscapes and their role in the global carbon balance. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Richards, J.F.; Flint, E.P.

    1993-10-01

    Since mid-September we have been engaged in final revision of the data base for South and Southeast Asia. In October we revised our second chapter for the forthcoming volume Effects of Land Use Change on Atmospheric Carbon Dioxide Concentrations, edited by Virginia Dale. ``Trends in Carbon Content of Vegetation in South and Southeast Asia Associated with Changes in Land Use``, in response to a second round of reviews. Both this chapter and `` Century of Land Use Change in South and Southeast Asia`` (submitted in revised form in July) are have been accepted and are now in the hands of the technical editor. our time series of land use data and carbon content estimates for live vegetation in 93 zones comprising thirteen Asian nations at four dates was finalized in the course of manuscript revision. We sent machine-readable copies of the spreadsheets containing tabular data for Southeast Asia to CDIAC in October, and the following month delivered the South Asian data. At the same time, we sent these files to the research groups of Sandra Brown and Charlie Hall, who have entered this information in their geographic information systems, and also to Skee Houghton.

  2. Technical Information on the Carbonation of the EBR-II Reactor, Summary Report Part 2: Application to EBR-II Primary Sodium System and Related Systems

    Energy Technology Data Exchange (ETDEWEB)

    Steven R. Sherman; Collin J. Knight

    2006-03-01

    Residual sodium is defined as sodium metal that remains behind in pipes, vessels, and tanks after the bulk sodium metal has been melted and drained from such components. The residual sodium has the same chemical properties as bulk sodium, and differs from bulk sodium only in the thickness of the sodium deposit. Typically, sodium is considered residual when the thickness of the deposit is less than 5-6 cm. This residual sodium must be removed or deactivated when a pipe, vessel, system, or entire reactor is permanently taken out of service, in order to make the component or system safer and/or to comply with decontamination and decomissioning regulations. As an alternative to the established residual sodium deactivation techniques (steam-and-nitrogen, wet vapor nitrogen, etc.), a technique involving the use of moisture and carbon dioxide has been developed. With this technique, sodium metal is converted into sodium bicarbonate by reacting it with humid carbon dioxide. Hydrogen is emitted as a by-product. This technique was first developed in the laboratory by exposing sodium samples to humidifed carbon dioxide under controlled conditions, and then demonstrated on a larger scale by treating residual sodium within the Experimental Breeder Reactor II (EBR-II) secondary cooling system, followed by the primary cooling system, respectively. The EBR-II facility is located at the Idaho National Laboratory (INL) in southeastern Idaho, USA. This report is Part 2 of a two-part report. This second report provides a supplement to the first report and describes the application of the humdidified carbon dioxide technique ("carbonation") to the EBR-II primary tank, primary cover gas systems, and the intermediate heat exchanger. Future treatment plans are also provided.

  3. Ecosystem carbon balance in a drier future: land-atmosphere exchanges of CO2, water and energy across semiarid southwestern North America

    Science.gov (United States)

    Biederman, J. A.; Scott, R. L.; Goulden, M.; Litvak, M. E.; Kolb, T.; Yépez, E. A.; Oechel, W. C.; Meyers, T. P.; Papuga, S. A.; Ponce-Campos, G.; Krofcheck, D. J.; Maurer, G. E.; Dore, S.; Garatuza, J.; Bell, T. W.; Krishnan, P.

    2015-12-01

    The southwest US and northwest Mexico are predicted to become warmer and drier, increasing disturbance, shifting ecosystem composition, and altering global CO2 cycling. However, direct measurements of ecosystem land-atmosphere carbon and water exchange in this region have lagged behind those in wetter regions. In this presentation we present a synthesis of CO2, water, and energy exchanges made at 25 Southwest eddy covariance sites (3-10 years each, n = 174 years). This regional gradient includes desert shrublands, grasslands, savannas, and forests and spans ranges of 200 - 800 mm in mean annual precipitation and 2 - 24 ⁰C mean annual temperature, a climate space that has been underrepresented in flux databases and publications. We compare measured fluxes against state-of-the-art remote sensing and modeling products representing current best regional estimates. We find that 65% of annual net ecosystem production of CO2 (NEP) is explained by water availability. Meanwhile, most of the unexplained NEP variability is related to site-specific differences persisting over the observation years, suggesting slow-changing controls such as demography (plant type, age, structure) and legacies of disturbance. Disturbances that kill plants without removing biomass, such as drought, tend to decrease productivity and increase respiration, shifting sites from carbon sinks to sources. However, following disturbances that removed biomass, such as fire, both productivity and respiration decline, with minimal impacts on NEP. Remote sensing and modeling match mean CO2 uptake measurements across spatial gradients in climate and plant functional type. However, measured uptake reveals 200-400% greater interannual variability than model estimates. High variability and sensitivity to water help us understand why semiarid ecosystems dominate the interannual variability of the terrestrial carbon sink in global accounting studies.

  4. ZnO Functionalization of Multi-walled Carbon Nanotubes for Methane Sensing at Single Parts Per Million Concentration Levels

    Science.gov (United States)

    This paper presents a novel atomic layer deposition (ALD) based ZnO functionalization of surface pre-treated multi-walled carbon nanotubes (MWCNTs) for highly sensitive methane chemoresistive sensors. The temperature optimization of the ALD process leads to enhanced ZnO nanopart...

  5. Silurian and Devonian source rocks and crude oils from the western part of Libya: Organic geochemistry, palynology and carbon stratigraphy

    NARCIS (Netherlands)

    Elkelani, Mohamed M.A.

    2015-01-01

    The Early Silurian “hot” shales and Late Devonian black shales are major regional oil and gas source rocks in North Africa. Their deposition probably played a major role in global carbon cycling in general because of the large areas of the ocean affected. Comparing the Libyan δ13C record with record

  6. Gradation of mechanical properties in gas-diffusion electrode. Part 2: Heterogeneous carbon fiber and damage evolution in cell layers

    Science.gov (United States)

    Poornesh, K. K.; Cho, C. D.; Lee, G. B.; Tak, Y. S.

    In PEM fuel cell, gas-diffusion electrode (GDE) plays very significant role in force transmission from bipolar plate to the membrane. This paper investigates the effects of geometrical heterogeneities of gas-diffusion electrode layer (gas-diffusion layer (GDL) and catalyst layer (CL)) on mechanical damage evolution and propagation. We present a structural integrity principle of membrane electrode assembly (MEA) based on the interlayer stress transfer capacity and corresponding cell layer material response. Commonly observable damages such as rupture of hydrophobic coating and breakage of carbon fiber in gas-diffusion layer are attributed to the ductile to brittle phase transition within a single carbon fiber. Effect of material inhomogeneity on change in modulus, hardness, contact stiffness, and electrical contact resistance is also discussed. Fracture statistics of carbon fiber and variations in flexural strength of GDL are studied. The damage propagation in CL is perceived to be influenced by the type of gradation and the vicinity from which crack originates. Cohesive zone model has been proposed based on the traction-separation law to investigate the damage propagation throughout the two interfaces (carbon fiber/CL and CL/membrane).

  7. Chemical processes of coal for use in power plants. Part 1: Approximate analysis and associated indexes of pulverized coal; Procesos quimicos del carbon para su uso en centrales termoelectricas. Parte 1: Analisis aproximado e indices asociados del carbon pulverizado

    Energy Technology Data Exchange (ETDEWEB)

    Altamirano-Bedolla, J. A.; Manzanares-Papayanopoulos, E.; Herrera-Velarde, J. R. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: emp@iie.org.mx

    2010-11-15

    The usage of hydrocarbons, such as natural gas, oil products and coal, will be the main source of energy to the mankind for next generations. Therefore, the actual research and technological developments point out to employ with high efficiency those fuels. The main interests are to release most of the energy as possible and to guide the combustion reactions. It is well known that during the combustion process of coal, the chemical energy is converted to thermal energy, which it allows the steam production, and therefore to produce energy through an electric generator. The main interest of the work presented here is to study the behavior of the coal combustion processes in function of the approximate analysis and some associate indices of that analysis, to point out the optimization of the coal usage as main fuel in electrical power generation plants. [Spanish] El uso de hidrocarburos como son el gas natural, los derivados del petroleo y el carbon mineral, continuara siendo en las proximas decadas la principal fuente de energia de la humanidad. Por consiguiente, la investigacion cientifica y los desarrollos tecnologicos actualmente se enfocan en emplear de manera mas eficiente dichos combustibles, satisfaciendo entre otros factores, dos intereses principales: liberar la mayor cantidad de energia, reduciendo al minimo el material combustible no quemado, y direccionar las reacciones del proceso de combustion para minimizar la cantidad de productos no deseados resultantes de la reaccion. A traves de los procesos quimicos de combustion del carbon, se transforma la energia quimica a energia termica, lo que permite la produccion de vapor para a su vez impulsar una turbina la cual esta acoplada a un generador electrico. El objetivo del presente trabajo es el estudio del comportamiento de los procesos quimicos que se llevan a cabo durante las reacciones de combus-tion del carbon en funcion del analisis aproximado y de los indices asociados resultantes de dicho analisis; lo

  8. Material and heat balance calculations for manufacturing of phosphoric acid activated carbon used in sugar refining%磷酸活化法制备糖用活性炭的物料和热量衡算

    Institute of Scientific and Technical Information of China (English)

    朱芸; 左宋林; 孙康; 许玉; 邓先伦

    2013-01-01

    按照目前磷酸活化杉木屑生产活性炭的常规工艺,分析并计算了年产1 500t糖用粉状活性炭生产的各个工序的物料和热量平衡.分析计算结果可以为磷酸活化法生产活性炭的工厂工艺设计、设备选型、能量消耗和成本核算提供基本依据,并可以为磷酸活化法工艺的改进和优化提供参考.%This paper calculated the material and heat balance of manufacturing phosphoric acid activated carbon used in sugar refining. The calculation was based on a conventional production line with Chinese fir sawdust as raw material and an annual capacity of 1 500 t. The results provided the fundamental data for process design, equipment selection, energy consumption evaluation and cost accounting of activated carbon manufacturing and helped optimizing the phosphoric acid activation process.

  9. Annual balances and extended seasonal modelling of carbon fluxes from a temperate fen cropped to festulolium and tall fescue under two-cut and three-cut harvesting regimes

    DEFF Research Database (Denmark)

    Kandel, Tanka; Elsgaard, Lars; Lærke, Poul Erik

    2017-01-01

    as biomass proxies. The sensitivity of the models was also tested on partial datasets including only alternate measurement campaigns and on datasets only from the crop growing period. Use of Ft in GPP models effectively corrected GPP overestimation in cold periods, and this approach was used throughout....... Annual fluxes obtained with ER models including RVI or GPP parameters were similar, and also annual GPP and ER fluxes obtained with full and partial datasets were similar. Annual CO2 fluxes and biomass yield were not significantly different in the crop/management combinations although the individual...... collars (n = 12) showed some variations in GPP (−1818 to −2409 g CO2-C m−2), ER (1071 to 1738 g CO2-C m−2), net ecosystem exchange (NEE, −669 to −949 g CO2-C m−2) and biomass yield (556 to 1044 g CO2-C m−2). Net ecosystem carbon balance (NECB), as the sum of NEE and biomass carbon export, was only...

  10. The results of development of oil and gas deposits using pumping of carbon dioxide into a stratum in the southwestern part of Hungary (VNR)

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    The development of oil and gas formations using carbon dioxide pumping has been successfully conducted since 1972 in the southwestern part of Hungary at the Budafa and Lovasi deposits. Gas from the gas formation is high pressure which contains CO2 and is pumped without a compressor into the oil formations which is a lower pressure stratum. At the stratum temperature of the collector and the implemented pumping conditions, the CO2 is only partially mixed with the stratum oil. After pumping the gas is rigidly displaced by water. During the water pumping gas and water are cyclically pumped into individual sectors of the formations depending on the coverage of the carbon dioxide. The development technology used is presented, along with the results of operations achieved over the last ten years.

  11. Constrained Allocation Flux Balance Analysis

    CERN Document Server

    Mori, Matteo; Martin, Olivier C; De Martino, Andrea; Marinari, Enzo

    2016-01-01

    New experimental results on bacterial growth inspire a novel top-down approach to study cell metabolism, combining mass balance and proteomic constraints to extend and complement Flux Balance Analysis. We introduce here Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic costs associated to growth are accounted for in an effective way through a single additional genome-wide constraint. Its roots lie in the experimentally observed pattern of proteome allocation for metabolic functions, allowing to bridge regulation and metabolism in a transparent way under the principle of growth-rate maximization. We provide a simple method to solve CAFBA efficiently and propose an "ensemble averaging" procedure to account for unknown protein costs. Applying this approach to modeling E. coli metabolism, we find that, as the growth rate increases, CAFBA solutions cross over from respiratory, growth-yield maximizing states (preferred at slow growth) to fermentative states with carbon overflow (preferr...

  12. Dizziness and Balance

    Science.gov (United States)

    AUDIOLOGY Dizziness and Balance Inform ation Seri es Our balance system helps us walk, run, and move without falling. ... if I have a problem with balance or dizziness? It is important to see your doctor if ...

  13. Microbial carbon recycling: an underestimated process controlling soil carbon dynamics - Part 2: A C3-C4 vegetation change field labelling experiment

    Science.gov (United States)

    Basler, A.; Dippold, M.; Helfrich, M.; Dyckmans, J.

    2015-11-01

    The mean residence times (MRT) of different compound classes of soil organic matter (SOM) do not match their inherent recalcitrance to decomposition. One reason for this is the stabilization within the soil matrix, but recycling, i.e. the reuse of "old" organic material to form new biomass may also play a role as it uncouples the residence times of organic matter from the lifetime of discrete molecules in soil. We analysed soil sugar dynamics in a natural 30-year old labelling experiment after a wheat-maize vegetation change to determine the extent of recycling and stabilization by assessing differences in turnover dynamics between plant and microbial-derived sugars: while plant-derived sugars are only affected by stabilization processes, microbial sugars may be subject to both, stabilization and recycling. To disentangle the dynamics of soil sugars, we separated different density fractions (free particulate organic matter (fPOM), light occluded particulate organic matter (≤ 1.6 g cm-3; oPOM1.6), dense occluded particulate organic matter (≤ 2 g cm-3; oPOM2) and mineral-associated organic matter (> 2 g cm-3; mineral)) of a silty loam under long-term wheat and maize cultivation. The isotopic signature of neutral sugars was measured by high pressure liquid chromatography coupled to isotope ratio mass spectrometry (HPLC/IRMS), after hydrolysis with 4 M Trifluoroacetic acid. While apparent MRT of sugars were comparable to total organic carbon in the bulk soil and mineral fraction, the apparent MRT of sugar carbon in the oPOM fractions were considerably lower than those of the total carbon of these fractions. This indicates that oPOM formation was fuelled by microbial activity feeding on new plant input. In the bulk soil, MRT of the mainly plant-derived xylose were significantly lower than those of mainly microbial-derived sugars like galactose, rhamnose, fucose, indicating that recycling of organic matter is an important factor regulating organic matter dynamics in

  14. Modelling ruptures of buried high pressure dense phase CO2 pipelines in carbon capture and storage applications - Part I. Validation

    OpenAIRE

    Wareing, CJ; Fairweather, M.; Falle, SAEG; Woolley, RM

    2015-01-01

    Carbon dioxide (CO2) capture and storage presents a short-term option for significantly reducing the amount of CO2 released into the atmosphere and mitigating the effects of climate change. To this end, National Grid initiated the COOLTRANS research programme to consider the pipeline transportation of high pressure dense phase CO2, including the development and application of a mathematical model for predicting the sonic near-field dispersion of pure CO2 following the venting or failure of su...

  15. Carbon-Isotope Composition of Biochemical Fractions and the Regulation of Carbon Balance in Leaves of the C3-Crassulacean Acid Metabolism Intermediate Clusia minor L. Growing in Trinidad.

    Science.gov (United States)

    Borland, A. M.; Griffiths, H.; Broadmeadow, MSJ.; Fordham, M. C.; Maxwell, C.

    1994-10-01

    Carbon-isotope ratios ([delta]13Cs) were measured for various bio-chemical fractions quantitatively extracted from naturally exposed and shaded leaves of the C3-Crassulacean acid metabolism (CAM) intermediate Clusia minor, sampled at dawn and dusk on days during the wet and dry seasons in Trinidad. As the activity of CAM increased in response to decreased availability of water and higher photon flux density, organic acids and soluble sugars were enriched in 13C by approximately 3.5 to 4%[per mille (thousand) sign] compared to plants sampled during the wet season. The induction of CAM was accompanied by a doubling in size of the reserve carbohydrate pools. Moreover, stoichiometric measurements indicated that degradation of both chloroplastic reserves and soluble sugars were necessary to supply phosphoenolpyruvate for the synthesis of organic acids at night. Results also suggest that two pools of soluble sugars exist in leaves of C. minor that perform CAM, one a vacuolar pool enriched in 13C and the second a transport pool depleted in 13C. Estimates of carbon-isotope discrimination expressed during CAM, derived from the trafficking among inorganic carbon, organic acids, and carbohydrate pools overnight, ranged from 0.9 to 3.1%[per mille (thousand) sign]. The [delta]13C of structural material did not change significantly between wet and dry seasons, indicating that most of the carbon used in growth was derived from C3 carboxylation.

  16. Development of New Types of Active Carbons, Inorganic Oxides and Phosphates as Selective Adsorbents and Carriers for Catalysts and their Industrial Application. Part II

    DEFF Research Database (Denmark)

    Marcussen, Lis

    1996-01-01

    Adsorption equilibria of carbon dioxide and methane on activated carbon. Experimental results and mathematical modelling.......Adsorption equilibria of carbon dioxide and methane on activated carbon. Experimental results and mathematical modelling....

  17. GFDL's ESM2 global coupled climate-carbon Earth System Models. Part I: physical formulation and baseline simulation characteristics

    Science.gov (United States)

    Dunne, John P.; John, Jasmin G.; Adcroft, Alistair J.; Griffies, Stephen M.; Hallberg, Robert W.; Shevalikova, Elena; Stouffer, Ronald J.; Cooke, William; Dunne, Krista A.; Harrison, Matthew J.; Krasting, John P.; Malyshev, Sergey L.; Milly, P.C.D.; Phillipps, Peter J.; Sentman, Lori A.; Samuels, Bonita L.; Spelman, Michael J.; Winton, Michael; Wittenberg, Andrew T.; Zadeh, Niki

    2012-01-01

    We describe the physical climate formulation and simulation characteristics of two new global coupled carbon-climate Earth System Models, ESM2M and ESM2G. These models demonstrate similar climate fidelity as the Geophysical Fluid Dynamics Laboratory's previous CM2.1 climate model while incorporating explicit and consistent carbon dynamics. The two models differ exclusively in the physical ocean component; ESM2M uses Modular Ocean Model version 4.1 with vertical pressure layers while ESM2G uses Generalized Ocean Layer Dynamics with a bulk mixed layer and interior isopycnal layers. Differences in the ocean mean state include the thermocline depth being relatively deep in ESM2M and relatively shallow in ESM2G compared to observations. The crucial role of ocean dynamics on climate variability is highlighted in the El Niño-Southern Oscillation being overly strong in ESM2M and overly weak ESM2G relative to observations. Thus, while ESM2G might better represent climate changes relating to: total heat content variability given its lack of long term drift, gyre circulation and ventilation in the North Pacific, tropical Atlantic and Indian Oceans, and depth structure in the overturning and abyssal flows, ESM2M might better represent climate changes relating to: surface circulation given its superior surface temperature, salinity and height patterns, tropical Pacific circulation and variability, and Southern Ocean dynamics. Our overall assessment is that neither model is fundamentally superior to the other, and that both models achieve sufficient fidelity to allow meaningful climate and earth system modeling applications. This affords us the ability to assess the role of ocean configuration on earth system interactions in the context of two state-of-the-art coupled carbon-climate models.

  18. Carbon balance, partitioning and photosynthetic acclimation in fruit-bearing grapevine (Vitis vinifera L. cv. Tempranillo) grown under simulated climate change (elevated CO2, elevated temperature and moderate drought) scenarios in temperature gradient greenhouses.

    Science.gov (United States)

    Salazar-Parra, Carolina; Aranjuelo, Iker; Pascual, Inmaculada; Erice, Gorka; Sanz-Sáez, Álvaro; Aguirreolea, Jone; Sánchez-Díaz, Manuel; Irigoyen, Juan José; Araus, José Luis; Morales, Fermín

    2015-02-01

    Although plant performance under elevated CO2 has been extensively studied in the past little is known about photosynthetic performance changing simultaneously CO2, water availability and temperature conditions. Moreover, despite of its relevancy in crop responsiveness to elevated CO2 conditions, plant level C balance is a topic that, comparatively, has received little attention. In order to test responsiveness of grapevine photosynthetic apparatus to predicted climate change conditions, grapevine (Vitis vinifera L. cv. Tempranillo) fruit-bearing cuttings were exposed to different CO2 (elevated, 700ppm vs. ambient, ca. 400ppm), temperature (ambient vs. elevated, ambient +4°C) and irrigation levels (partial vs. full irrigation). Carbon balance was followed monitoring net photosynthesis (AN, C gain), respiration (RD) and photorespiration (RL) (C losses). Modification of environment (13)C isotopic composition (δ(13)C) under elevated CO2 (from -10.30 to -24.93‰) enabled the further characterization of C partitioning into roots, cuttings, shoots, petioles, leaves, rachides and berries. Irrespective of irrigation level and temperature, exposure to elevated CO2 induced photosynthetic acclimation of plants. C/N imbalance reflected the inability of plants grown at 700ppm CO2 to develop strong C sinks. Partitioning of labeled C to storage organs (main stem and roots) did not avoid accumulation of labeled photoassimilates in leaves, affecting negatively Rubisco carboxylation activity. The study also revealed that, after 20 days of treatment, no oxidative damage to chlorophylls or carotenoids was observed, suggesting a protective role of CO2 either at current or elevated temperatures against the adverse effect of water stress.

  19. Huella del Carbono. Parte 1: Conceptos, Métodos de Estimación y Complejidades Metodológicas Carbon Footprint. Part 1: Concepts, Estimation Methods and Methodological Complexities

    Directory of Open Access Journals (Sweden)

    César Espíndola

    2012-01-01

    Full Text Available Se presenta y analiza el concepto de huella del carbono, su origen, su relación con los gases efecto invernadero, y sobre los procedimientos para cuantificarla. El efecto invernadero provoca que la energía que llega a la Tierra sea devuelta más lentamente, por lo que es mantenida más tiempo junto a la superficie elevando la temperatura. Es aceptado hoy en día que este efecto es producido por algunos gases liberados en forma natural o por las acciones humanas. La Huella de Carbono es considerada una de las más importantes herramientas para cuantificar las emisiones de gases efecto invernadero y en forma muy general, representa la cantidad de gases efecto invernadero emitidos a la atmósfera derivados de las actividades de producción o consumo de bienes y servicios. Al no existir consenso en cuanto a la definición y menos en la cuantificación de la huella del carbono, la primera parte de este trabajo analiza las principales corrientes y enfoques actuales.The concept of Carbon Footprint, its origin, its relation with greenhouse gases and the methods to quantify it are presented and analyzed. The so-called greenhouse effect causes that the energy that reaches the earth at a certain rate is returned to a slower rate, increasing the temperature of the earth surface. Additionally, it is nowadays accepted that this effect is produced by some gases that are naturally emitted or produced by human actions. The Carbon Footprint is considered to be one of the most important tools for quantifying greenhouse emissions and in a general form it represents the quantity of gases emitted to the atmosphere and that is produced by human activities, and by goods and service consumption. Since there is no consensus about the definition of Carbon Footprint or the forms of quantifying it, this first part of the paper series analyzes the main concept and the main present views on the Carbon Footprint.

  20. Scenario analysis of carbon emissions' anti-driving effect on Qingdao's energy structure adjustment with an optimization model, Part II: Energy system planning and management.

    Science.gov (United States)

    Wu, C B; Huang, G H; Liu, Z P; Zhen, J L; Yin, J G

    2017-03-01

    In this study, an inexact multistage stochastic mixed-integer programming (IMSMP) method was developed for supporting regional-scale energy system planning (EPS) associated with multiple uncertainties presented as discrete intervals, probability distributions and their combinations. An IMSMP-based energy system planning (IMSMP-ESP) model was formulated for Qingdao to demonstrate its applicability. Solutions which can provide optimal patterns of energy resources generation, conversion, transmission, allocation and facility capacity expansion schemes have been obtained. The results can help local decision makers generate cost-effective energy system management schemes and gain a comprehensive tradeoff between economic objectives and environmental requirements. Moreover, taking the CO2 emissions scenarios mentioned in Part I into consideration, the anti-driving effect of carbon emissions on energy structure adjustment was studied based on the developed model and scenario analysis. Several suggestions can be concluded from the results: (a) to ensure the smooth realization of low-carbon and sustainable development, appropriate price control and fiscal subsidy on high-cost energy resources should be considered by the decision-makers; (b) compared with coal, natural gas utilization should be strongly encouraged in order to insure that Qingdao could reach the carbon discharges peak value in 2020; (c) to guarantee Qingdao's power supply security in the future, the construction of new power plants should be emphasised instead of enhancing the transmission capacity of grid infrastructure.

  1. On the optical properties of carbon nanotubes. Part I. A general formula for the dynamical optical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, Morten Grud, E-mail: morteng@math.aau.dk [Department of Mathematical Sciences, Aalborg University, Fredrik Bajers Vej 7G, 9220 Aalborg (Denmark); Ricaud, Benjamin, E-mail: benjamin.ricaud@epfl.ch [Laboratoire de Traitement des Signaux 2, École Polytechnique Fédérale de Lausanne, Lausanne, Vaud (Switzerland); Savoie, Baptiste, E-mail: baptiste.savoie@gmail.com [Dublin Institute for Advanced Studies, School of Theoretical Physics, 10 Burlington Road, Dublin 04 (Ireland)

    2016-02-15

    This paper is the first one in a series of two articles in which we revisit the optical properties of single-walled carbon nanotubes (SWNTs). Produced by rolling up a graphene sheet, SWNTs owe their intriguing properties to their cylindrical quasi-one-dimensional (quasi-1D) structure (the ratio length/radius is experimentally of order of 10{sup 3}). We model SWNT by circular cylinders of small diameters on the surface of which the conduction electron gas is confined by the electric field generated by the fixed carbon ions. The pair-interaction potential considered is the 3D Coulomb potential restricted to the cylinder. To reflect the quasi-1D structure, we introduce a 1D effective many-body Hamiltonian which is the starting-point of our analysis. To investigate the optical properties, we consider a perturbation by a uniform time-dependent electric field modeling an incident light beam along the longitudinal direction. By using Kubo’s method, we derive within the linear response theory an asymptotic expansion in the low-temperature regime for the dynamical optical conductivity at fixed density of particles. The leading term only involves the eigenvalues and associated eigenfunctions of the (unperturbed) 1D effective many-body Hamiltonian and allows us to account for the sharp peaks observed in the optical absorption spectrum of SWNT.

  2. Technical Information on the Carbonation of the EBR-II Reactor, Summary Report Part 1: Laboratory Experiments and Application to EBR-II Secondary Sodium System

    Energy Technology Data Exchange (ETDEWEB)

    Steven R. Sherman

    2005-04-01

    Residual sodium is defined as sodium metal that remains behind in pipes, vessels, and tanks after the bulk sodium metal has been melted and drained from such components. The residual sodium has the same chemical properties as bulk sodium, and differs from bulk sodium only in the thickness of the sodium deposit. Typically, sodium is considered residual when the thickness of the deposit is less than 5-6 cm. This residual sodium must be removed or deactivated when a pipe, vessel, system, or entire reactor is permanently taken out of service, in order to make the component or system safer and/or to comply with decommissioning regulations. As an alternative to the established residual sodium deactivation techniques (steam-and-nitrogen, wet vapor nitrogen, etc.), a technique involving the use of moisture and carbon dioxide has been developed. With this technique, sodium metal is converted into sodium bicarbonate by reacting it with humid carbon dioxide. Hydrogen is emitted as a by-product. This technique was first developed in the laboratory by exposing sodium samples to humidified carbon dioxide under controlled conditions, and then demonstrated on a larger scale by treating residual sodium within the Experimental Breeder Reactor II (EBR-II) secondary cooling system, followed by the primary cooling system, respectively. The EBR-II facility is located at the Idaho National Laboratory (INL) in southeastern Idaho, U.S.A. This report is Part 1 of a two-part report. It is divided into three sections. The first section describes the chemistry of carbon dioxide-water-sodium reactions. The second section covers the laboratory experiments that were conducted in order to develop the residual sodium deactivation process. The third section discusses the application of the deactivation process to the treatment of residual sodium within the EBR-II secondary sodium cooling system. Part 2 of the report, under separate cover, describes the application of the technique to residual sodium

  3. Balance in Assessment

    Science.gov (United States)

    White, Richard

    2007-01-01

    The review by Black and Wiliam of national systems makes clear the complexity of assessment, and identifies important issues. One of these is "balance": balance between local and central responsibilities, balance between the weights given to various purposes of schooling, balance between weights for various functions of assessment, and balance…

  4. Response of aboveground carbon balance to long-term, experimental enhancements in precipitation seasonality is contingent on plant community type in cold-desert rangelands

    Science.gov (United States)

    McAbee, Kathryn; Reinhardt, Keith; Germino, Matthew; Bosworth, Andrew

    2017-01-01

    Semi-arid rangelands are important carbon (C) pools at global scales. However, the degree of net C storage or release in water-limited systems is a function of precipitation amount and timing, as well as plant community composition. In northern latitudes of western North America, C storage in cold-desert ecosystems could increase with boosts in wintertime precipitation, in which climate models predict, due to increases in wintertime soil water storage that enhance summertime productivity. However, there are few long-term, manipulative field-based studies investigating how rangelands will respond to altered precipitation amount or timing. We measured aboveground C pools and fluxes at leaf, soil, and ecosystem scales over a single growing season in plots that had 200 mm of supplemental precipitation added in either winter or summer for the past 21 years, in shrub- and exotic-bunchgrass-dominated garden plots. At our cold-desert site (298 mm precipitation during the study year), we hypothesized that increased winter precipitation would stimulate the aboveground C uptake and storage relative to ambient conditions, especially in plots containing shrubs. Our hypotheses were generally supported: ecosystem C uptake and long-term biomass accumulation were greater in winter- and summer-irrigated plots compared to control plots in both vegetation communities. However, substantial increases in the aboveground biomass occurred only in winter-irrigated plots that contained shrubs. Our findings suggest that increases in winter precipitation will enhance C storage of this widespread ecosystem, and moreso in shrub- compared to grass-dominated communities.

  5. Microprocessor-Controlled Laser Balancing System

    Science.gov (United States)

    Demuth, R. S.

    1985-01-01

    Material removed by laser action as part tested for balance. Directed by microprocessor, laser fires appropriate amount of pulses in correct locations to remove necessary amount of material. Operator and microprocessor software interact through video screen and keypad; no programing skills or unprompted system-control decisions required. System provides complete and accurate balancing in single load-and-spinup cycle.

  6. Carbon composites based on multiaxial multiply stitched preforms. Part 3: Biaxial tension, picture frame and compression tests of the preforms

    NARCIS (Netherlands)

    Lomov, S.V.; Barburski, M.; Stoilova, Tz.; Verpoest, I.; Akkerman, R.; Loendersloot, R.; Thije, ten R.H.W.

    2005-01-01

    Deformability of bi- and quadri-axial multi-axial multiply stitched preforms is studied in biaxial tension, shear (picture frame test) and compression. The results complement KES-F measurements in the low load range, reported in the Part 2 of the series (Compos A, 34, 2003, 359–70). The biaxial tens

  7. Carbon Budget of Russian Forests

    Directory of Open Access Journals (Sweden)

    A. Z. Shvidenko

    2014-02-01

    Full Text Available Net Ecosystem Carbon Balance (NECB of Russian forests for 2007–2009 is presented based on consistent application of applied systems analysis and modern information technologies. Use of landscape-ecosystem approach resulted in the NECB at 546±120 Tg C year–1, or 66±15 g C m–2 year–1. There is a substantial difference between the NECB of European and Asian parts, as well as the clear zonal gradients within these geographical regions. While the total carbon sink is high, large forest areas, particularly on permafrost, serve as a carbon source. The ratio between net primary production and soil heterotrophic respiration, together with natural and human-induced disturbances are major drivers of the magnitude and spatial distribution of the NECB of forest ecosystems. Using the Bayesian approach, mutual constraints of results that are obtained by independent methods enable to decrease uncertainties of the final result.

  8. Fate and transport of monoterpenes through soils. Part II: calculation of the effect of soil temperature, water saturation and organic carbon content.

    Science.gov (United States)

    van Roon, André; Parsons, John R; Krap, Lenny; Govers, Harrie A J

    2005-09-01

    This theoretical study was performed to investigate the influence of soil temperature, soil water content and soil organic carbon fraction on the mobility of monoterpenes (C10HnOn') applied as pesticides to a top soil layer. This mobility was expressed as the amount volatilized and leached from the contaminated soil layer after a certain amount of time. For this, (slightly modified) published analytical solutions to a one dimensional, homogeneous medium, diffusion/advection/biodegradation mass balance equation were used. The required input-parameters were determined in a preceding study. Because the monoterpenes studied differ widely in the values for their physico-chemical properties, the relative importance of the various determinants also differed widely. Increasing soil water saturation reduced monoterpene vaporization and leaching losses although a modest increase was usually observed at high soil water contents. Organic matter served as the major retention domain, reducing volatilization and leaching losses. Increasing temperature resulted in higher volatilization and leaching losses. Monoterpene mobility was influenced by vertical water flow. Volatilization losses could be reduced by adding a clean soil layer on top of the contaminated soil. Detailed insight into the specific behaviour of different monoterpenes was obtained by discussing intermediate calculation results; the transport retardation factors and effective soil diffusion coefficients. One insight was that the air-water interface compartment is probably not an important partitioning domain for monoterpenes in most circumstances. The results further indicated that biodegradation is an important process for monoterpenes in soil.

  9. Carbon footprint and environmental impacts of print products from cradle to grave. Results from the LEADER project (part 1)

    Energy Technology Data Exchange (ETDEWEB)

    Pihkola, H.; Nors, M.; Kujanpaeae, M.; Helin, T.; Kariniemi, M.; Pajula, T. (VTT Technical Research Centre of Finland, Espoo (Finland)); Dahlbo, H.; Koskela, S. (Finnish Environment Institute, Helsinki (Finland))

    2010-12-15

    The report presents the main results of the LEADER project that was ongoing in Finland between the years 2007-2010. The aim of the project was to study the environmental impacts occurring during the life cycle of print products. The scope of the project was focused on printed media products. In the study, life cycle assessments and carbon footprints were calculated for five case products: heatset offset printed magazine, coldset offset printed newspaper, sheetfed offset printed book, electrophotography printed photobook and rotogravure printed advertisement. The environmentally extended input-output model ENVIMAT was applied to provide an estimate of the environmental impacts related to the production and consumption of print products in Finland. Additionally, the development of environmental performance within different printing methods is evaluated and the environmental indicators specific for the printing phase are discussed. (orig.)

  10. Negative leave balances

    CERN Document Server

    Human Resources Department

    2005-01-01

    Members of the personnel entitled to annual leave and, where appropriate, saved leave and/or compensatory leave are requested to take note of the new arrangements described below, which were recommended by the Standing Concertation Committee (SCC) at its meeting on 1Â September 2005 and subsequently approved by the Director-General. The changes do not apply to members of the personnel participating in the Progressive Retirement Programme (PRP) or the Part-time Work as a pre-retirement measure, for whom the specific provisions communicated at the time of joining will continue to apply. Â Negative balances in annual leave, saved leave and/or compensatory leave accounts at the end of the leave year (30th September) and on the date on which bonuses are credited to the saved leave account (31st December): Where members of the personnel have a leave account with a negative balance on 30Â September and/or 31Â December, leave will automatically be transferred from one account to another on the relevant dates i...

  11. Negative leave balances

    CERN Document Server

    Human Resources Department

    2005-01-01

    Members of the personnel entitled to annual leave and, where appropriate, saved leave and/or compensatory leave are requested to take note of the new arrangements described below, which were recommended by the Standing Concertation Committee (SCC) at its meeting on 1 September 2005 and subsequently approved by the Director-General. The changes do not apply to members of the personnel participating in the Progressive Retirement Programme (PRP) or the Part-time Work as a pre-retirement measure, for whom the specific provisions communicated at the time of joining will continue to apply.  Negative balances in annual leave, saved leave and/or compensatory leave accounts at the end of the leave year (30th September) and on the date on which bonuses are credited to the saved leave account (31st December): Where members of the personnel have a leave account with a negative balance on 30 September and/or 31 December, leave will automatically be transferred from one account to another on the relevant dates in or...

  12. Are bioenergy production systems carbon neutral? An overview of the work of IEA Bioenergy Task 38 on greenhouse gas balances of biomass and bioenergy systems

    Energy Technology Data Exchange (ETDEWEB)

    Cowie, A.; George, B. [Univ. of New England, Armidale, NSW (Australia)

    2010-07-01

    The bioenergy industry is growing rapidly in response to concerns over climate change and high oil prices. However, there are serious concerns about the sustainability of the industry, as well as about the environmental impacts of off-site activities. The International Energy Agency's (IEA) Task 38 was established to develop a method of calculating the net greenhouse gas (GHG) mitigation benefit of bioenergy and sequestration projects. Task 38 focuses on the methods used to assess the GHG benefits of bioenergy systems when compared with fossil fuel systems. A full life cycle approach was used to assess the GHG emissions associated with the production and handling of biomass, as well as the nitrous oxide (N{sub 2}O) emissions emitted from fertilized soils, and emissions resulting from the production of fertilizer, herbicide, and the manufacture and construction of power stations. Methods for including indirect land use change where biomass production is displacing food production are also being discussed as part of the task. To date, the study has indicated that materials substitution or co-firing applications have greater mitigation benefits than other bioenergy systems.

  13. Balancing the Energy-Water Nexus

    Energy Technology Data Exchange (ETDEWEB)

    Dell, Jan

    2010-09-15

    Optimizing the complex tradeoffs in the Energy-Water Nexus requires quantification of energy use, carbon emitted and water consumed. Water is consumed in energy production and is often a constraint to operations. More global attention and investment has been made on reducing carbon emissions than on water management. Review of public reporting by the largest 107 global power producers and 50 companies in the oil/gas industry shows broad accounting on carbon emissions but only partial reporting on water consumption metrics. If the Energy-Water Nexus is to be balanced, then water must also be measured to be optimally managed with carbon emissions.

  14. Physiology of Geobacter metallireducens under excess and limitation of electron donors. Part I. Batch cultivation with excess of carbon sources.

    Science.gov (United States)

    Marozava, Sviatlana; Röling, Wilfred F M; Seifert, Jana; Küffner, Robert; von Bergen, Martin; Meckenstock, Rainer U

    2014-06-01

    For microorganisms that play an important role in bioremediation, the adaptation to swift changes in the availability of various substrates is a key for survival. The iron-reducing bacterium Geobacter metallireducens was hypothesized to repress utilization of less preferred substrates in the presence of high concentrations of easily degradable compounds. In our experiments, acetate and ethanol were preferred over benzoate, but benzoate was co-consumed with toluene and butyrate. To reveal overall physiological changes caused by different single substrates and a mixture of acetate plus benzoate, a nano-liquid chromatography-tandem mass spectrometry-based proteomic approach (nano-LC-MS/MS) was performed using label-free quantification. Significant differential expression during growth on different substrates was observed for 155 out of 1477 proteins. The benzoyl-CoA pathway was found to be subjected to incomplete repression during exponential growth on acetate in the presence of benzoate and on butyrate as a single substrate. Peripheral pathways of toluene, ethanol, and butyrate degradation were highly expressed only during growth on the corresponding substrates. However, low expression of these pathways was detected in all other tested conditions. Therefore, G. metallireducens seems to lack strong carbon catabolite repression under high substrate concentrations, which might be advantageous for survival in habitats rich in fatty acids and aromatic hydrocarbons.

  15. TiO{sub 2} activation by using activated carbon as a support. Part II. Photoreactivity and FTIR study

    Energy Technology Data Exchange (ETDEWEB)

    Arana, J.; Dona-Rodriguez, J.M.; Tello Rendon, E.; Garriga i Cabo, C.; Gonzalez-Diaz, O.; Herrera-Melian, J.A.; Perez-Pena, J. [Centro Instrumental para el Desarrollo de la Investigacion Aplicada (CIDIA), Parque Cientifico y Tecnologico, Universidad de Las Palmas de Gran Canaria, Campus de Tafira, 35017 Las Palmas de Gran Canaria (Spain); Colon, G.; Navio, J.A. [Instituto de Ciencia de Materiales de Sevilla, Centro Mixto CSIC-Universidad de Sevilla, Americo Vespucio s/n, 41092 Sevilla (Spain)

    2003-08-20

    It has been demonstrated that the modification of the TiO{sub 2} acid-base properties by the presence of activated carbon (AC) considerably modify the interaction of some molecules with the catalyst surface and hence its photocatalytic characteristics. FTIR studies have shown that while phenol interacts with TiO{sub 2} yielding a phenoxide, in the catalyst low AC containing catalysts mixtures the surfacial hydroxylic groups are inserted in the aromatic ring in the symmetric position to the -OH group. Additionally, the 4-aminophenol study shows that the molecule interacts with the TiO{sub 2} surface by means of the amino group, while in the catalyst containing AC the interaction takes place through the hydroxylic group. These results have confirmed the catalyst acid-base properties changes determined by the characterisation studies already performed. Also, it has been observed that catalysts with the lowest AC content show better catalytic behaviour than the untreated TiO{sub 2} and those with higher AC load. Another interesting result is the efficiency of these catalysts under solar irradiation.

  16. TiO{sub 2} activation by using activated carbon as a support. Part I. Surface characterisation and decantability study

    Energy Technology Data Exchange (ETDEWEB)

    Arana, J.; Dona-Rodriguez, J.M.; Tello Rendon, E.; Garriga i Cabo, C.; Gonzalez-Diaz, O.; Herrera-Melian, J.A.; Perez-Pena, J. [Photocatalysis and Electrochemical Laboratory, Parque Cientifico y Tecnologico, University of Las Palmas de Gran Canaria, E-35017 Las Palmas de Gran Canaria, Gran Canaria (Spain); Colon, G.; Navio, J.A. [Instituto de Ciencia de Materiales de Sevilla, Centro Mixto CSIC-Universidad de Sevilla, Americo Vespucio s/n. 41092, Sevilla (Spain)

    2003-08-20

    In the present work, the effect of mixing TiO{sub 2} with different portions of activated carbon (AC) has been studied. Transmission electron microscopy (TEM), scanning electron micrograph (SEM), laser scattering, FTIR and UV spectrophotometric analysis have shown changes of some of the TiO{sub 2} physico-chemical characteristics in catalysts containing an AC concentration lower than 15% in weight. Changes in the catalyst colour, the vibration bands of the hydroxylic groups from FTIR studies and the UV absorption spectrum have been observed. It seems that these changes correspond with TiO{sub 2} acid-base changes. SEM and TEM studies show a perfect TiO{sub 2} particles distribution on the AC surface in catalysts with lower AC contents, that also yields a homogeneous particle size distribution. One of the most interesting features of the resulting catalysts is their fast decantability in comparison with that of TiO{sub 2}. This way one of the most important drawbacks of photocatalysis, the catalyst separation from the solution, may be overcome.The present study shows that the AC not only exerts a synergistic effect when is combined with TiO{sub 2} as some authors suggest, but it also modifies the catalyst characteristics.

  17. Vibration impact acoustic emission technique for identification and analysis of defects in carbon steel tubes: Part A Statistical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Halim, Zakiah Abd [Universiti Teknikal Malaysia Melaka (Malaysia); Jamaludin, Nordin; Junaidi, Syarif [Faculty of Engineering and Built, Universiti Kebangsaan Malaysia, Bangi (Malaysia); Yahya, Syed Yusainee Syed [Universiti Teknologi MARA, Shah Alam (Malaysia)

    2015-04-15

    Current steel tubes inspection techniques are invasive, and the interpretation and evaluation of inspection results are manually done by skilled personnel. This paper presents a statistical analysis of high frequency stress wave signals captured from a newly developed noninvasive, non-destructive tube inspection technique known as the vibration impact acoustic emission (VIAE) technique. Acoustic emission (AE) signals have been introduced into the ASTM A179 seamless steel tubes using an impact hammer, and the AE wave propagation was captured using an AE sensor. Specifically, a healthy steel tube as the reference tube and four steel tubes with through-hole artificial defect at different locations were used in this study. The AE features extracted from the captured signals are rise time, peak amplitude, duration and count. The VIAE technique also analysed the AE signals using statistical features such as root mean square (r.m.s.), energy, and crest factor. It was evident that duration, count, r.m.s., energy and crest factor could be used to automatically identify the presence of defect in carbon steel tubes using AE signals captured using the non-invasive VIAE technique.

  18. Effects of climatic changes on carbon dioxide and water vapor fluxes in boreal forest ecosystems of European part of Russia

    Science.gov (United States)

    Olchev, A.; Novenko, E.; Desherevskaya, O.; Krasnorutskaya, K.; Kurbatova, J.

    2009-10-01

    Effects of possible climatic and vegetation changes on H2O and CO2 fluxes in boreal forest ecosystems of the central part of European Russia were quantified using modeling and experimental data. The future pattern of climatic conditions for the period up to 2100 was derived using the global climatic model ECHAM5 (Roeckner et al 2003 The Atmospheric General Circulation Model ECHAM 5. PART I: Model Description, Report 349 (Hamburg: Max-Planck Institute for Meteorology) p 127) with the A1B emission scenario. The possible trends of future vegetation changes were obtained by reconstructions of vegetation cover and paleoclimatic conditions in the Late Pleistocene and Holocene, as provided from pollen and plant macrofossil analysis of profiles in the Central Forest State Natural Biosphere Reserve (CFSNBR). Applying the method of paleoanalogues demonstrates that increasing the mean annual temperature, even by 1-2 °C, could result in reducing the proportion of spruce in boreal forest stands by up to 40%. Modeling experiments, carried out using a process-based Mixfor-SVAT model, show that the expected future climatic and vegetation changes lead to a significant increase of net ecosystem exchange (NEE) and gross primary productivity (GPP) of the boreal forests. Despite the expected warming and moistening of the climate, the modeling experiments indicate a relatively weak increase of annual evapotranspiration (ET) and even a reduction of transpiration (TR) rates of forest ecosystems compared to present conditions.

  19. Rotary Bed Reactor for Chemical-Looping Combustion with Carbon Capture. Part 1: Reactor Design and Model Development

    KAUST Repository

    Zhao, Zhenlong

    2013-01-17

    Chemical-looping combustion (CLC) is a novel and promising technology for power generation with inherent CO2 capture. Currently, almost all of the research has been focused on developing CLC-based interconnected fluidized-bed reactors. In this two-part series, a new rotary reactor concept for gas-fueled CLC is proposed and analyzed. In part 1, the detailed configuration of the rotary reactor is described. In the reactor, a solid wheel rotates between the fuel and air streams at the reactor inlet and exit. Two purging sectors are used to avoid the mixing between the fuel stream and the air stream. The rotary wheel consists of a large number of channels with copper oxide coated on the inner surface of the channels. The support material is boron nitride, which has high specific heat and thermal conductivity. Gas flows through the reactor at elevated pressure, and it is heated to a high temperature by fuel combustion. Typical design parameters for a thermal capacity of 1 MW have been proposed, and a simplified model is developed to predict the performances of the reactor. The potential drawbacks of the rotary reactor are also discussed. © 2012 American Chemical Society.

  20. Balanced Scorecard voor inkoop

    NARCIS (Netherlands)

    Honing, van der R.; Schotanus, F.

    2003-01-01

    Een Balanced Scorecard kan ontwikkeld worden voor de hele organisatie, maar ook voor onderdelen daarvan. In dit artikel wordt ingegaan op de ontwikkeling van een Balanced Scorecard voor de inkoopafdeling

  1. Strength and Balance Exercises

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Strength and Balance Exercises Updated:Sep 8,2016 If ... Be Safe While Being Active - Stretching & Flexibility Exercises - Strength & Balance Exercises - Problems & Solutions for Being Active - FAQs ...

  2. 近10 a青海高原东部土地利用/覆被变化及碳效应%Land use/cover change and its impact on soil carbon in eastern part of Qinghai Plateau in near 10 years

    Institute of Scientific and Technical Information of China (English)

    曾永年; 陈晓玲; 靳文凭

    2014-01-01

    and promote its sustainable development. It is reported in literature that the land use/cover change is one of the main factors which may influence the regional carbon balance, and it can change the ecosystem carbon cycle and alter the regional even global carbon balance among different carbon pools. Based on the multi-temporal remote sensing data from Landsat TM, in this paper, we used the agriculture area of Haidong city located in the eastern part of Qinghai Plateau as a case study to investigate land use/cover change and consequently its impact on the regional carbon balance. The research was to be used as a reference for balancing the relationship among economic development, eco-system protection and cultivated land conservation and pursuit of low-carbon land use. Firstly, the intensity and directions of different types of land use pattern on eastern region of Qinghai Plateau in the last decade was analyzed by using change of land use intensity index. Then, carbon effect caused by eight main types of land use change including:cultivated land into forest land, forest land into cultivated land, cultivated land into grass, grass into cultivated land, forest land into grass, grass into forest land, cultivated land into construction land and construction land into cultivated land was studied. The results indicated that the implement of“Grain for Green Project” and progress made from the Western Development Strategy from the central government significant changed land use/cover in Haidong from 1999 to 2009. There were three kinds of land use types including forest, construction land and unutilized land, which increased by 67%, 56% and 1.14%, respectively and two types including cultivated land and grassland which decreased by 30%and 12%, respectively. Besides, the decrease of cultivated land was caused by construction land expansion and cultivated land conversion to different land uses. As a convention, the land use type, such as cultivated, forests and grass, are

  3. Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions and a new approach for estimating net ecosystem exchange from inventory-based data

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-01

    We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000 2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a 327 252 TgC yr1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (248 TgC yr1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (297 TgC yr1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated tobe a small net source (+18 TgC yr1) due to land use change between 1993 and 2002. We compare these inventorybased estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is 511 TgC yr1 and 931 TgC yr1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional 239 TgC yr1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

  4. Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions, and a new approach for estimating net ecosystem exchange from inventory-based data

    Science.gov (United States)

    Hayes, Daniel J.; Turner, David P.; Stinson, Graham; McGuire, A. David; Wei, Yaxing; West, Tristram O.; Heath, Linda S.; de Jong, Bernardus; McConkey, Brian G.; Birdsey, Richard A.; Kurz, Werner A.; Jacobson, Andrew R.; Huntzinger, Deborah N.; Pan, Yude; Post, W. Mac; Cook, Robert B.

    2012-01-01

    We develop an approach for estimating net ecosystem exchange (NEE) using inventory-based information over North America (NA) for a recent 7-year period (ca. 2000–2006). The approach notably retains information on the spatial distribution of NEE, or the vertical exchange between land and atmosphere of all non-fossil fuel sources and sinks of CO2, while accounting for lateral transfers of forest and crop products as well as their eventual emissions. The total NEE estimate of a -327 ± 252 TgC yr-1 sink for NA was driven primarily by CO2 uptake in the Forest Lands sector (-248 TgC yr-1), largely in the Northwest and Southeast regions of the US, and in the Crop Lands sector (-297 TgC yr-1), predominantly in the Midwest US states. These sinks are counteracted by the carbon source estimated for the Other Lands sector (+218 TgC yr-1), where much of the forest and crop products are assumed to be returned to the atmosphere (through livestock and human consumption). The ecosystems of Mexico are estimated to be a small net source (+18 TgC yr-1) due to land use change between 1993 and 2002. We compare these inventory-based estimates with results from a suite of terrestrial biosphere and atmospheric inversion models, where the mean continental-scale NEE estimate for each ensemble is -511 TgC yr-1 and -931 TgC yr-1, respectively. In the modeling approaches, all sectors, including Other Lands, were generally estimated to be a carbon sink, driven in part by assumed CO2 fertilization and/or lack of consideration of carbon sources from disturbances and product emissions. Additional fluxes not measured by the inventories, although highly uncertain, could add an additional -239 TgC yr-1 to the inventory-based NA sink estimate, thus suggesting some convergence with the modeling approaches.

  5. Discussion of Balanced Relative Compression Height ξb (ρb)in Strengthened Beam with Carbon Fiber - Reinforced Polymer Sheets%碳纤维加固钢筋混凝土梁的界限相对受压区高度研究

    Institute of Scientific and Technical Information of China (English)

    江世永; 飞渭; 李迎涛; 彭飞飞; 杜文龙; 王跃文

    2002-01-01

    根据材料的本构关系及平截面假定,结合预应力加固的概念推导出了碳纤维加固钢筋混凝土梁时的三种不同的界限受压区高度,并给出了界限状态下钢筋、混凝土、碳纤维片材的相应应力.%Based on the stress - strain relationship and principle of co - deformation,this paper analyses the balanced relative compression height ξb (ρb) of strengthened beam with Carbon Fiber - Reinforced Polymer(CFRP) sheets, and presents the concept of balanced section. Based on this concept, the method of deciding balanced relative compression height is proposed.

  6. Characterization of reactive flow-induced evolution of carbonate rocks using digital core analysis- part 1: Assessment of pore-scale mineral dissolution and deposition

    Science.gov (United States)

    Qajar, Jafar; Arns, Christoph H.

    2016-09-01

    The application of X-ray micro-computed tomography (μ-CT) for quantitatively characterizing reactive-flow induced pore structure evolution including local particle detachment, displacement and deposition in carbonate rocks is investigated. In the studies conducted in this field of research, the experimental procedure has involved alternating steps of imaging and ex-situ core sample alteration. Practically, it is impossible to return the sample, with micron precision, to the same position and orientation. Furthermore, successive images of a sample in pre- and post-alteration states are usually taken at different conditions such as different scales, resolutions and signal-to-noise ratios. These conditions accompanying with subresolution features in the images make voxel-by-voxel comparisons of successive images problematic. In this paper, we first address the respective challenges in voxel-wise interpretation of successive images of carbonate rocks subject to reactive flow. Reactive coreflood in two carbonate cores with different rock types are considered. For the first rock, we used the experimental and imaging results published by Qajar et al. (2013) which showed a quasi-uniform dissolution regime. A similar reactive core flood was conducted in the second rock which resulted in wormhole-like dissolution regime. We particularly examine the major image processing operations such as transformation of images to the same grey-scale, noise filtering and segmentation thresholding and propose quantitative methods to evaluate the effectiveness of these operations in voxel-wise analysis of successive images of a sample. In the second part, we generalize the methodology based on the three-phase segmentation of normalized images, microporosity assignment and 2D histogram of image intensities to estimate grey-scale changes of individual image voxels for a general case where the greyscale images are segmented into arbitrary number of phases. The results show that local (voxel

  7. 45 CFR 1628.5 - Fund balance deficits.

    Science.gov (United States)

    2010-10-01

    ... prior year shall be identified as questioned costs under 45 CFR part 1630. (d) The recipient's request... 45 Public Welfare 4 2010-10-01 2010-10-01 false Fund balance deficits. 1628.5 Section 1628.5... FUND BALANCES § 1628.5 Fund balance deficits. (a) Sound financial management practices such as...

  8. Researching and Experiencing Motivation: A Plea for "Balanced Research"

    Science.gov (United States)

    Li, Na

    2006-01-01

    Intrigued by van Lier's call for "balanced teaching", I come up with a proposal of "balanced research". In this paper, I describe my personal involvement in a four-month teaching/data-gathering experience (as a part of my doctoral research project on task motivation) which shows that it both necessitates and ends up involving such a "balanced"…

  9. Carbon Goes To…

    Science.gov (United States)

    Savasci, Funda

    2014-01-01

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

  10. 碳排放与区域低碳发展--“新型城镇化低碳发展国际学术论坛”部分主题演讲摘录%Carbon Emissions and Regional Low-Carbon Development:Parts of the Speech Excerpts of “International Forum on New Urbanization & Low Carbon Development”

    Institute of Scientific and Technical Information of China (English)

    《重庆理工大学学报 社会科学 》

    2015-01-01

    Editorial Note:Humanity gains organic matter derives from the nature so as to obtain energy which is used in the production and life,thus releases carbon dioxide in a variety of ways.Increasing carbon dioxide in the atmosphere is like a thick layer of glass and makes the earth into a huge greenhouse.And the global war-ming will lead to the problems such as global rainfall distribution,melting glaciers and permafrost,rising sea levels,etc.,which not only harms the balance of ecosystem of nature,and threatens the survival of mankind. In recent years,in response to climate change,various countries and regions have carried out active exploration and research,and reached some consensus,and introduced some corresponding policies and measures.For ex-ample,China premier Li Keqiang said that we must insist on deepening reform and innovation driving,and we must create new technologies,new products and new pattern through the mass entrepreneurship and innovation, and we must strengthen energy conservation and environmental protection industries and strictly control the ex-pansion of energy intensive and highly polluting industries,thus to form the energy conservation and low carbon industry system,to cultivate new growth points and to promote healthy economic development at the leading group meeting on countries’respond to climate change and energy conservation and emissions reduction work on June 12nd,2015.On the “International Forum on New Urbanization &Low Carbon Development”sponsored by Chongqing Technology and Business University from September 19th to 20th,2015,more than 20 experts and scholars from Beijing,Chongqing,Hubei,Guangdong and other provinces and cities in China and the Unit-ed States of California and other places in the world presented and discussed issues such as carbon emissions peak measures,carbon emissions reduction targets for carbon emissions,regional and industry status quo,new urbanization,industrial structure transformation and so on at the

  11. Nitrogen-doped Co/Co9S8/partly-graphitized carbon as durable catalysts for oxygen reduction in microbial fuel cells

    Science.gov (United States)

    Li, Rui; Dai, Ying; Chen, Baibing; Zou, Jinlong; Jiang, BaoJiang; Fu, Honggang

    2016-03-01

    Durability of catalysts for oxygen reduction reaction (ORR) is the key factor for governing the performance of microbial fuel cells (MFCs). The cobalt (Co) chelated polyaniline (PANI) is used as the nitrogen and carbon sources to prepare the N-doped Co/Co9S8/partly-graphitized carbon (Co/Co9S8/NPGC) catalysts. Structure-activity correlations for Co/Co9S8/NPGC are explored by tuning the heating temperature (600-1000 °C) to investigate how the active components (Co/Co9S8) and N-doped functionalities (N-species) influence the ORR activity. As temperature increases, the gradual crystallization of Co originating from the reduction of Co9S8 is conducted to form the Co/Co9S8 heterojunction. MFCs with Co/Co9S8/NPGC (800 °C) cathode obtain the highest power density (1156 mW m-2) and the lowest charge transfer resistance (11.1 Ω) after 75 d running, which are better than commercial Pt/C (10 wt.%). Although the sole Co9S8 plays a limited role in ORR, the resulting Co/Co9S8 is found to be indispensable to achieve high activity and durability in MFCs cathodes. The dominant ORR pathways of Co/Co9S8/NPGC (800 and 900 °C) are the four-electron O2 reduction, which are attributed to the co-existence of pyridinic N, graphitic N and Co-Nx species. These new N-doped metal sulfide/PGC composites show promise for applications in MFCs.

  12. The Stable Isotopes of Carbon and Nitrogen in the Bones of Domestic Animals from three Cities of the European Part of Russia: First Results and Interpretations

    Directory of Open Access Journals (Sweden)

    Yavorskaya Liliya Vyacheslavovna

    2015-03-01

    Full Text Available The paper outlines the results of first purposeful research on isotopic composition (carbon 13С and nitrogen 15N in the bones collagen of domestic and wild animals from medieval towns at the European part of Russia. The published information about δ 13С и δ 15N was obtained from 61 samples of osteological collections of Yaroslavl, Rostov and Bolgar. The average values of carbon isotope in cattle bones are almost the same in all three cities. By contrast, these values for horses and pigs from Rostov and Bolgar are higher than for Yaroslavl animals. Unusual similarity for δ13С in the bones of sheep, camels and dogs among themselves from the Bolgar collection were fixed. The comparative analysis of the values δ13С in bones of domestic and wild animals allowed us to propose the hypothesis that sheep, camels and dogs appeared in Bolgar from the southern arid areas. The data on δ15N showed the inexplicably high accumulation of the nitrogen stable isotope in sheep and camel bones from the collection of Bolgar and in beaver bones from Rostov samples. This is probably due to the peculiarities of the diet of these dogs, enriched by the entrails of domestic ungulates or fish. The minimum values of δ15N in the bones of dogs from Bolgar reflect the specific diet of herding dogs with a minimal volume of meat. Simultaneously the data of 15N in sheep and camel bones from Bolgar collection and in beaver bones from Rostov samples howed the inexplicably high level of nitrogen stable isotope accumulation.

  13. On the feasibility of monitoring carbon monoxide in the lower troposphere from a constellation of northern hemisphere geostationary satellites: Global scale assimilation experiments (Part II)

    Science.gov (United States)

    Barré, Jérôme; Edwards, David; Worden, Helen; Arellano, Avelino; Gaubert, Benjamin; Da Silva, Arlindo; Lahoz, William; Anderson, Jeffrey

    2016-09-01

    This paper describes the second phase of an Observing System Simulation Experiment (OSSE) that utilizes the synthetic measurements from a constellation of satellites measuring atmospheric composition from geostationary (GEO) Earth orbit presented in part I of the study. Our OSSE is focused on carbon monoxide observations over North America, East Asia and Europe where most of the anthropogenic sources are located. Here we assess the impact of a potential GEO constellation on constraining northern hemisphere (NH) carbon monoxide (CO) using data assimilation. We show how cloud cover affects the GEO constellation data density with the largest cloud cover (i.e., lowest data density) occurring during Asian summer. We compare the modeled state of the atmosphere (Control Run), before CO data assimilation, with the known "true" state of the atmosphere (Nature Run) and show that our setup provides realistic atmospheric CO fields and emission budgets. Overall, the Control Run underestimates CO concentrations in the northern hemisphere, especially in areas close to CO sources. Assimilation experiments show that constraining CO close to the main anthropogenic sources significantly reduces errors in NH CO compared to the Control Run. We assess the changes in error reduction when only single satellite instruments are available as compared to the full constellation. We find large differences in how measurements for each continental scale observation system affect the hemispherical improvement in long-range transport patterns, especially due to seasonal cloud cover. A GEO constellation will provide the most efficient constraint on NH CO during winter when CO lifetime is longer and increments from data assimilation associated with source regions are advected further around the globe.

  14. Functional balance tests

    Directory of Open Access Journals (Sweden)

    Parvin Raji

    2012-12-01

    Full Text Available Background and Aim: All activities of daily living need to balance control in static and dynamic movements. In recent years, a numerous increase can be seen in the functional balance assessment tools. Functional balance tests emphasize on static and dynamic balance, balance in weight transfer, the equilibrium response to the imbalances, and functional mobility. These standardized and available tests assess performance and require minimal or no equipment and short time to run. Functional balance is prerequisite for the most static and dynamic activities in daily life and needs sufficient interaction between sensory and motor systems. According to the critical role of balance in everyday life, and wide application of functional balance tests in the diagnosis and assessment of patients, a review of the functional balance tests was performed.Methods: The Google Scholar, PubMed, Science Direct, Scopus, Magiran, Iran Medex, and IranDoc databases were reviewed and the reliable and valid tests which were mostly used by Iranian researchers were assessed.Conclusion: It seems that Berg balance scale (BBS have been studied by Iranian and foreign researches more than the other tests. This test has high reliability and validity in elderly and in the most neurological disorders.

  15. Constrained Allocation Flux Balance Analysis

    Science.gov (United States)

    Mori, Matteo; Hwa, Terence; Martin, Olivier C.

    2016-01-01

    New experimental results on bacterial growth inspire a novel top-down approach to study cell metabolism, combining mass balance and proteomic constraints to extend and complement Flux Balance Analysis. We introduce here Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic costs associated to growth are accounted for in an effective way through a single additional genome-wide constraint. Its roots lie in the experimentally observed pattern of proteome allocation for metabolic functions, allowing to bridge regulation and metabolism in a transparent way under the principle of growth-rate maximization. We provide a simple method to solve CAFBA efficiently and propose an “ensemble averaging” procedure to account for unknown protein costs. Applying this approach to modeling E. coli metabolism, we find that, as the growth rate increases, CAFBA solutions cross over from respiratory, growth-yield maximizing states (preferred at slow growth) to fermentative states with carbon overflow (preferred at fast growth). In addition, CAFBA allows for quantitatively accurate predictions on the rate of acetate excretion and growth yield based on only 3 parameters determined by empirical growth laws. PMID:27355325

  16. MODIFICATION OF CARBON STEEL BY LASER SURFACE MELTING: PART I: EFFECT OF LASER BEAM TRAVELLING SPEED ON MICROSTRUCTURAL FEATURES AND SURFACE HARDNESS

    Directory of Open Access Journals (Sweden)

    Hashem F. El-Labban

    2013-01-01

    Full Text Available The present study aims to improve the surface hardness of carbon steel by application of laser surface melting of effective conditions. The travelling speed of laser beam during this treatment is one of the important treatment conditions. This study aims to investigate the effect of laser surface melting with different beam speeds on macro and microstructure as well as the hardness distribution through the thickness of carbon steel. To achieve this target, three different travelling speeds (1500, 1000 and 500 mm min-1 at a constant beam power of 800 W were chosen in this study. The resulted laser treated specimens were investigated in macro and microscopically scale using optical and scanning electron microscope. Hardness measurements were also carried out through the thickness of the laser treated specimens. The laser treated areas with all used travelling speeds results in melted and solidified zone on the surface of the steel. In the same time, Plates of acicular martensite structure were observed within the upper part of the melted and solidified zone in almost all experimental conditions, while some bainite structure in ferrite grains are detected in its lower part. By increasing the travelling speed, the depth of the laser treated zone was decreases, while travelling speed has much less significant effect on the laser treated zone width. The size of the formed martensite plates was increased by decreasing the travelling speed from 1500 to 500 mm min-1. On the other hand, the travelling speed has a straight effect on the length of the acicular martensite; as the travelling speed increases, the acicular martensite became longer, while it shows fine acicular martensite at lower travelling speeds. The depth that full martensite structure can be reached is increased by increasing travelling speed. At lower travelling speed (500 mm min-1, large amount of bainite structure is observed at the center of the treated zone up to its lower end. The

  17. Soil Organic Carbon Balance and Nitrogen Cycling in Plastic Film Mulched Croplands in Rainfed Farming Systems%旱作地膜覆盖农田土壤有机碳平衡及氮循环特征

    Institute of Scientific and Technical Information of China (English)

    李小刚; 李凤民

    2015-01-01

    近10余年来随着应用面积的迅速增加,地膜覆盖对中国北方旱作农田生产力可持续性的影响受到越来越多的关注。文章对地膜覆盖栽培技术增产效果作了简要评述,重点综述了近年来关于地膜覆盖对农田土壤有机碳平衡和氮循环过程影响的研究进展。地膜覆盖沟垄栽培技术有效减轻了旱作农业区水热条件不足对粮食生产造成的限制,从而对提高耕地生产力发挥了重要作用。对大量文献分析发现,地膜覆盖沟垄栽培技术的增产效果具有明显的地域性,在中国北方半干旱区范围内,水热限制越强烈的地区增产效应越明显。地膜覆盖对农田土壤有机碳平衡和氮循环影响的研究还比较薄弱。目前的研究结果表明,地膜覆盖促进土壤有机碳矿化但同时增加作物根系有机碳输入,初步显示地膜覆盖对土壤有机碳含量的影响可能是中性的。地膜覆盖促进土壤有机氮矿化,提高氮素的有效性,增加作物对氮素的吸收,影响化肥氮的作物利用效率、淋溶和挥发损失,但并不明确是否增加反硝化作用。基于目前研究现状,文章提出了旱作地膜覆盖农田需要加强研究的主要领域:(1)土壤有机质稳定性及其增强机制研究;(2)农田养分管理的系统性研究;(3)在水热条件相对较好的旱作农业区,建议结合秸秆覆盖开展更多研究。%With the rapid increase in the application area, the effects of plastic film mulch on the sustainability and productivity of rainfed croplands received more and more attention from society. In this review, after briefly summarizing the yield increase effect of plastic film mulch cropping in semiarid rainfed areas, we focused on recent advances in the field of plastic film mulch effects on the soil organic carbon (SOC) balance and nitrogen (N) cycling. Plastic film mulch, especially when combined with a ridge

  18. Development of New Types of Active Carbons, Inorganic Oxides and Phosphates as Selective Adsorbents and Carriers for Catalysts and their Application in Industry. Part III

    DEFF Research Database (Denmark)

    Marcussen, Lis

    1998-01-01

    Adsorption equilibria of ethane and isobutane on activated carbon. Experimental results and mathematical modelling.......Adsorption equilibria of ethane and isobutane on activated carbon. Experimental results and mathematical modelling....

  19. The carbon cycle in the Australian Community Climate and Earth System Simulator (ACCESS-ESM1) - Part 1: Model description and pre-industrial simulation

    Science.gov (United States)

    Law, R. M.; Ziehn, T.; Matear, R. J.; Lenton, A.; Chamberlain, M. A.; Stevens, L. E.; Wang, Y. P.; Srbinovsky, J.; Bi, D.; Yan, H.; Vohralik, P. F.

    2015-09-01

    Earth System Models (ESMs) that incorporate carbon-climate feedbacks represent the present state of the art in climate modelling. Here, we describe the Australian Community Climate and Earth System Simulator (ACCESS)-ESM1 that combines existing ocean and land carbon models into the physical climate model to simulate exchanges of carbon between the land, atmosphere and ocean. The land carbon model can optionally include both nitrogen and phosphorous limitation on the land carbon uptake. The ocean carbon model simulates the evolution of nitrate, oxygen, dissolved inorganic carbon, alkalinity and iron with one class of phytoplankton and zooplankton. From two multi-centennial simulations of the pre-industrial period with different land carbon model configurations, we evaluate the equilibration of the carbon cycle and present the spatial and temporal variability in key carbon exchanges. For the land carbon cycle, leaf area index is simulated reasonably, and seasonal carbon exchange is well represented. Interannual variations of land carbon exchange are relatively large, driven by variability in precipitation and temperature. We find that the response of the ocean carbon cycle shows reasonable agreement with observations and very good agreement with existing Coupled Model Intercomparison Project (CMIP5) models. While our model over estimates surface nitrate values, the primary productivity agrees well with observations. Our analysis highlights some deficiencies inherent in the carbon models and where the carbon simulation is negatively impacted by known biases in the underlying physical model. We conclude the study with a brief discussion of key developments required to further improve the realism of our model simulation.

  20. The carbon cycle in the Australian Community Climate and Earth System Simulator (ACCESS-ESM1 – Part 1: Model description and pre-industrial simulation

    Directory of Open Access Journals (Sweden)

    R. M. Law

    2015-09-01

    Full Text Available Earth System Models (ESMs that incorporate carbon-climate feedbacks represent the present state of the art in climate modelling. Here, we describe the Australian Community Climate and Earth System Simulator (ACCESS-ESM1 that combines existing ocean and land carbon models into the physical climate model to simulate exchanges of carbon between the land, atmosphere and ocean. The land carbon model can optionally include both nitrogen and phosphorous limitation on the land carbon uptake. The ocean carbon model simulates the evolution of nitrate, oxygen, dissolved inorganic carbon, alkalinity and iron with one class of phytoplankton and zooplankton. From two multi-centennial simulations of the pre-industrial period with different land carbon model configurations, we evaluate the equilibration of the carbon cycle and present the spatial and temporal variability in key carbon exchanges. For the land carbon cycle, leaf area index is simulated reasonably, and seasonal carbon exchange is well represented. Interannual variations of land carbon exchange are relatively large, driven by variability in precipitation and temperature. We find that the response of the ocean carbon cycle shows reasonable agreement with observations and very good agreement with existing Coupled Model Intercomparison Project (CMIP5 models. While our model over estimates surface nitrate values, the primary productivity agrees well with observations. Our analysis highlights some deficiencies inherent in the carbon models and where the carbon simulation is negatively impacted by known biases in the underlying physical model. We conclude the study with a brief discussion of key developments required to further improve the realism of our model simulation.

  1. Balancing of linkages and robot manipulators advanced methods with illustrative examples

    CERN Document Server

    Arakelian, Vigen

    2015-01-01

    In this book advanced balancing methods for planar and spatial linkages, hand operated and automatic robot manipulators are presented. It is organized into three main parts and eight chapters. The main parts are the introduction to balancing, the balancing of linkages and the balancing of robot manipulators. The review of state-of-the-art literature including more than 500 references discloses particularities of shaking force/moment balancing and gravity compensation methods. Then new methods for balancing of linkages are considered. Methods provided in the second part of the book deal with the partial and complete shaking force/moment balancing of various linkages. A new field for balancing methods applications is the design of mechanical systems for fast manipulation. Special attention is given to the shaking force/moment balancing of robot manipulators. Gravity balancing methods are also discussed. The suggested balancing methods are illustrated by numerous examples.

  2. Towards an Understanding of Atmospheric Balance

    Science.gov (United States)

    Errico, Ronald M.

    2015-01-01

    During a 35 year period I published 30+ pear-reviewed papers and technical reports concerning, in part or whole, the topic of atmospheric balance. Most used normal modes, either implicitly or explicitly, as the appropriate diagnostic tool. This included examination of nonlinear balance in several different global and regional models using a variety of novel metrics as well as development of nonlinear normal mode initialization schemes for particular global and regional models. Recent studies also included the use of adjoint models and OSSEs to answer some questions regarding balance. lwill summarize what I learned through those many works, but also present what l see as remaining issues to be considered or investigated.

  3. Preliminary geologic mapping of Cretaceous and Tertiary formations in the eastern part of the Little Snake River coal field, Carbon County, Wyoming

    Science.gov (United States)

    Haacke, Jon E.; Barclay, C. S. Venable; Hettinger, Robert D.

    2016-09-30

    In the 1970s and 1980s, C.S. Venable Barclay conducted geologic mapping of areas primarily underlain by Cretaceous coals in the eastern part of the Little Snake River coal field (LSR) in Carbon County, southwest Wyoming. With some exceptions, most of the mapping data were never published. Subsequently, after his retirement from the U.S. Geological Survey (USGS), his field maps and field notebooks were archived in the USGS Field Records. Due to a pending USGS coal assessment of the Little Snake River coal field area and planned geological mapping to be conducted by the Wyoming State Geological Survey, Barclay’s mapping data needed to be published to support these efforts. Subsequently, geologic maps were scanned and georeferenced into a geographic information system, and project and field notes were scanned into Portable Document Format (PDF) files. Data for seventeen 7½-minute quadrangles are presented in this report. This publication is solely intended to compile the mapping data as it was last worked on by Barclay and provides no interpretation or modification of his work.

  4. [Blood acid-base balance of sportsmen during physical activity].

    Science.gov (United States)

    Petrushova, O P; Mikulyak, N I

    2014-01-01

    The aim of this study was to investigate the acid-base balance parameters in blood of sportsmen by physical activity. Before exercise lactate concentration in blood was normal. Carbon dioxide pressure (рСО2), bicarbonate concentration (НСО3 -), base excess (BE), were increased immediately after physical activity lactate concentration increased, while pH, BE, НСО3 -, рСО2 decreased in capillary blood of sportsmen. These changes show the development of lactate-acidosis which is partly compensated with bicarbonate buffering system and respiratory alkalosis. During postexercise recovery lactate concentration decreased, while рСО2, НСО3 -, BE increased. The results of this study can be used for diagnostics of acid-base disorders and their medical treatment for preservation of sportsmen physical capacity.

  5. Identifying Balance in a Balanced Scorecard System

    Science.gov (United States)

    Aravamudhan, Suhanya; Kamalanabhan, T. J.

    2007-01-01

    In recent years, strategic management concepts seem to be gaining greater attention from the academicians and the practitioner's alike. Balanced Scorecard (BSC) concept is one such management concepts that has spread in worldwide business and consulting communities. The BSC translates mission and vision statements into a comprehensive set of…

  6. Conclusion: The balanced company

    DEFF Research Database (Denmark)

    Scheuer, John Damm; Jensen, Inger

    2013-01-01

    This concluding chapter brings together the various research findings of the book "The balanced company - organizing for the 21st Century" and develops a general overview of their implications for our understanding of the balancing processes unfolding in companies and organizations....

  7. Keeping Your Balance

    Science.gov (United States)

    ... News & Events Press Releases NOF in the News Osteoporosis in the News Press/Media Kit NOF Events Blog Advocacy NOF Store Shopping Cart Home › Patients › Fractures/Fall Prevention › Exercise/Safe Movement › Keeping Your Balance Keeping Your Balance ...

  8. Leadership: A Balancing Act

    Science.gov (United States)

    Hines, Thomas E.

    2011-01-01

    Maintaining balance in leadership can be difficult because balance is affected by the personality, strengths, and attitudes of the leader as well as the complicated environment within and outside the community college itself. This article explores what being a leader at the community college means, what the threats are to effective leadership, and…

  9. Balancing Trust and Control

    DEFF Research Database (Denmark)

    Jagd, Søren

    This paper focuses on the leadership challenge of balancing trust and control. The relation between trust and control has for a long time been a puzzling issue for management researchers. In the paper I first show that there has been a dramatic change in the way the relation between trust...... and control has been conceptualized in trust research. While the relation between trust and control earlier was conceptualized as a more or less stable balance between trust and control, more recent research conceptualizes the relation between trust and control more as a dynamical process that involves...... an ongoing process of balancing the relation between trust and control. Second, taking the departure in the recent conceptualization of the balance between trust and control as an interactive process I discuss the challenges for management in handling this more subtle balancing of trust and control...

  10. Global estimates of boreal forest carbon stocks and flux

    Science.gov (United States)

    Bradshaw, Corey J. A.; Warkentin, Ian G.

    2015-05-01

    The boreal ecosystem is an important global reservoir of stored carbon and a haven for diverse biological communities. The natural disturbance dynamics there have historically been driven by fire and insects, with human-mediated disturbances increasing faster than in other biomes globally. Previous research on the total boreal carbon stock and predictions of its future flux reveal high uncertainty in regional patterns. We reviewed and standardised this extensive body of quantitative literature to provide the most up-to-date and comprehensive estimates of the global carbon balance in the boreal forest. We also compiled century-scale predictions of the carbon budget flux. Our review and standardisation confirmed high uncertainty in the available data, but there is evidence that the region's total carbon stock has been underestimated. We found a total carbon store of 367.3 to 1715.8 Pg (1015 g), the mid-point of which (1095 Pg) is between 1.3 and 3.8 times larger than any previous mean estimates. Most boreal carbon resides in its soils and peatlands, although estimates are highly uncertain. We found evidence that the region might become a net carbon source following a reduction in carbon uptake rate from at least the 1980s. Given that the boreal potentially constitutes the largest terrestrial carbon source in the world, in one of the most rapidly warming parts of the globe (Walsh, 2014), how we manage these stocks will be influential on future climate dynamics.

  11. Design of the Key Parts of Force Balanced Constant Spring Hangers Based on MATLAB%基于MATLAB的力平衡式恒力吊关键零件的设计

    Institute of Scientific and Technical Information of China (English)

    章志荣

    2011-01-01

    对力平衡式恒力吊作机构分析,根据其工作原理建立其刀形凸轮的曲线微分方程,使用MATLAB程序求解凸轮曲线微分方程并绘制凸轮曲线。建立恒力吊主弹簧的优化设计数学模型,使用MATLAB遗传算法工具求解,实现主弹簧的优化设计。用这种方法设计力平衡式恒力吊,可以提高设计质量和设计效率。%A mechanics model for force balanced constant spring hangers is put forward.The curve equation of knife cams is induced from the working principle of constant hanger.The curve equation is solved and the curves of cams are also plotted with MATLAB.The main spring mathematical model of optimal design is established.Parameters of the main spring are optimized with the MATLAB genetic algorithm tool.Design force balanced constant spring hangers in this way would improve the design quality and design efficiency.

  12. Carbon-Carbon Piston Architectures

    Science.gov (United States)

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

    2000-01-01

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

  13. Load Balancing Scientific Applications

    Energy Technology Data Exchange (ETDEWEB)

    Pearce, Olga Tkachyshyn [Texas A & M Univ., College Station, TX (United States)

    2014-12-01

    The largest supercomputers have millions of independent processors, and concurrency levels are rapidly increasing. For ideal efficiency, developers of the simulations that run on these machines must ensure that computational work is evenly balanced among processors. Assigning work evenly is challenging because many large modern parallel codes simulate behavior of physical systems that evolve over time, and their workloads change over time. Furthermore, the cost of imbalanced load increases with scale because most large-scale scientific simulations today use a Single Program Multiple Data (SPMD) parallel programming model, and an increasing number of processors will wait for the slowest one at the synchronization points. To address load imbalance, many large-scale parallel applications use dynamic load balance algorithms to redistribute work evenly. The research objective of this dissertation is to develop methods to decide when and how to load balance the application, and to balance it effectively and affordably. We measure and evaluate the computational load of the application, and develop strategies to decide when and how to correct the imbalance. Depending on the simulation, a fast, local load balance algorithm may be suitable, or a more sophisticated and expensive algorithm may be required. We developed a model for comparison of load balance algorithms for a specific state of the simulation that enables the selection of a balancing algorithm that will minimize overall runtime.

  14. Consideration of Dynamical Balances

    Science.gov (United States)

    Errico, Ronald M.

    2015-01-01

    The quasi-balance of extra-tropical tropospheric dynamics is a fundamental aspect of nature. If an atmospheric analysis does not reflect such balance sufficiently well, the subsequent forecast will exhibit unrealistic behavior associated with spurious fast-propagating gravity waves. Even if these eventually damp, they can create poor background fields for a subsequent analysis or interact with moist physics to create spurious precipitation. The nature of this problem will be described along with the reasons for atmospheric balance and techniques for mitigating imbalances. Attention will be focused on fundamental issues rather than on recipes for various techniques.

  15. Study on blood clotting effect of different solvent extraction parts of Mume carbon%乌梅炭不同溶剂萃取部位凝血作用

    Institute of Scientific and Technical Information of China (English)

    潘新; 许腊英; 许康; 余倩倩; 石琪

    2011-01-01

    目的:研究乌梅经炒炭炮制后不同溶剂(石油醚、氯仿、醋酸乙酯)萃取物的凝血作用,筛选最佳活性萃取物部位,为进一步分离活性成分做基础.方法:运用溶剂提取萃取法制备乌梅炭乙醇提取物3种不同溶剂的萃取部位浸膏.运用毛细管法测定小鼠凝血时间,断尾法测定小鼠出血时间.结果:乌梅炭水煎液与乌梅炭氯仿、醋酸乙酯等部位凝血时间及出血时间较阴性对照组短.乌梅炭石油醚部位与乌梅较对照组凝血时间及出血时间无明显差异.乌梅炭氯仿部位较其醋酸乙酯部位凝血时间及出血时间短.结论:乌梅与乌梅炭石油醚部位无明显凝血作用,乌梅炭与乌梅炭氯仿、醋酸乙酯等部位凝血作用显著,乌梅炭氯仿部位为最佳活性部位.%OBJECTIVE To study the blood clotting effect of different solvent extraction (petroleum ether,chloroform,ethyl acetate)of Mume carbon,and to pick up the optimal active extract parts; providing a basis for further separating active components research. METHODS Solvent extraction method was used to prepare solvent extraction of Mume carbon. Blood clotting time was determined by capillary method,bleeding time was measured by broken tail method in mice. RESULTS The bleeding time and blood clotting time of water decoction, chloroform and ethyl acetate extract parts of Mume carbon were shorter than that of negative control. Petroleum ether part and Mume carbon were no obvious difference compared with negative control. Blood clotting time and bleeding time of chloroform part was shorter than that of ethyl acetate part. CONCLUSION Mume and petroleum ether part have no obvious blood clotting effect. Mume carbon and chloroform, ethyl acetate parts have significant blood clotting effect. Chloroform part is the best active components.

  16. The Balanced Company

    DEFF Research Database (Denmark)

    is to be achieved and what should be avoided? • Through what types of processes are the criteria, conditions and values that are to be realised or taken into consideration constructed and decided upon? • What characterises the content, differences and complexity of the different types of values and criteria...... that a company is respected in wider society and behaves according to ethical standards. Strategists and Leaders need to make balanced choices about long-term goals and the allocation of resources. They need to analyse, understand and adjust strategies to market, political, value and technology related changes...... in their environments. Communication specialists need to make balanced decisions which take the different value systems and assumptions of stakeholders into consideration. Change specialists need to balance the need for continuity and change. Managers need to make balanced decisions about whether to achieve goals...

  17. Energy balance measurement

    DEFF Research Database (Denmark)

    Dhurandhar, N V; Schoeller, D; Brown, A W;

    2014-01-01

    Energy intake (EI) and physical activity energy expenditure (PAEE) are key modifiable determinants of energy balance, traditionally assessed by self-report despite its repeated demonstration of considerable inaccuracies. We argue here that it is time to move from the common view that self-reports...... of energy balance.International Journal of Obesity advance online publication, 23 December 2014; doi:10.1038/ijo.2014.199.......Energy intake (EI) and physical activity energy expenditure (PAEE) are key modifiable determinants of energy balance, traditionally assessed by self-report despite its repeated demonstration of considerable inaccuracies. We argue here that it is time to move from the common view that self......-reports of EI and PAEE are imperfect, but nevertheless deserving of use, to a view commensurate with the evidence that self-reports of EI and PAEE are so poor that they are wholly unacceptable for scientific research on EI and PAEE. While new strategies for objectively determining energy balance...

  18. The full GHG balance over two crop rotations at an agricultural site near Gebesee, Thuringia, Germany

    Science.gov (United States)

    Kutsch, Werner Leo; Brümmer, Christian; Don, Catharina; Dechow, Rene; Fuß, Roland; Freibauer, Annette; Schulze, Ernst-Detlef; Kolle, Olaf; Ziegler, Waldemar

    2013-04-01

    Gebesee in Thuringia is the eldest cropland eddy covariance (EC) site in Europe. The site has been part of CarboEurope, NitroEurope and IMECC and has been selected to be one of the German Level 1 sites within the European research infrastructure ICOS. Continuous measurements of NEE by EC, NPP by regular harvesting, lateral in- and outputs of carbon and nitrogen as well as climatic parameters have been conducted since 2001. Automated chamber measurements of N2O and CH4 were conducted since 2007. Fluxes of these greenhouse gases (GHG) for the years 2001 - 2006 were calculated based on a Fuzzy Logic model calibrated by means of the chamber measurements. In this study we present NEE, NBP and full GHG balances of over two rotation periods (2001 - 2004 and 2005 - 2009, respectively) comprising four times winter wheat, two times potatoes and one cropping period of oil seed rape, sugar beet and barley each. The GHG balance is dominated by moderate losses of soil organic matter (~120 +/- 50 g C m-2 y-1) and by N2O emissions of about 0.17 g N2O-N m-2 y-1 (50 g C-eq m-2 y-1). The on-site emissions of GHG balance about 43 % of the harvested carbon.

  19. Carbon dioxide utilization in a microalga-based biorefinery: Efficiency of carbon removal and economic performance under carbon taxation.

    Science.gov (United States)

    Wiesberg, Igor Lapenda; Brigagão, George Victor; de Medeiros, José Luiz; de Queiroz Fernandes Araújo, Ofélia

    2017-03-08

    Coal-fired power plants are major stationary sources of carbon dioxide and environmental constraints demand technologies for abatement. Although Carbon Capture and Storage is the most mature route, it poses severe economic penalty to power generation. Alternatively, this penalty is potentially reduced by Carbon Capture and Utilization, which converts carbon dioxide to valuable products, monetizing it. This work evaluates a route consisting of carbon dioxide bio-capture by Chlorella pyrenoidosa and use of the resulting biomass as feedstock to a microalgae-based biorefinery; Carbon Capture and Storage route is evaluated as a reference technology. The integrated arrangement comprises: (a) carbon dioxide biocapture in a photobioreactor, (b) oil extraction from part of the produced biomass, (b) gasification of remaining biomass to obtain bio-syngas, and (c) conversion of bio-syngas to methanol. Calculation of capital and operational expenditures are estimated based on mass and energy balances obtained by process simulation for both routes (Carbon Capture and Storage and the biorefinery). Capital expenditure for the biorefinery is higher by a factor of 6.7, while operational expenditure is lower by a factor of 0.45 and revenues occur only for this route, with a ratio revenue/operational expenditure of 1.6. The photobioreactor is responsible for one fifth of the biorefinery capital expenditure, with footprint of about 1000 ha, posing the most significant barrier for technical and economic feasibility of the proposed biorefinery. The Biorefinery and Carbon Capture and Storage routes show carbon dioxide capture efficiency of 73% and 48%, respectively, with capture cost of 139$/t and 304$/t. Additionally, the biorefinery has superior performance in all evaluated metrics of environmental impacts.

  20. Heat balance of a molten carbonate fuel cell production hydrogen for a polymer electrolyte fuel cell-CoCell; Waermehaushalt einer Karbonat-Brennstoffzelle zur Wasserstoffherstellung fuer eine Polymerelektrolyt-Brennstoffzelle

    Energy Technology Data Exchange (ETDEWEB)

    Adamek, L.

    2006-10-17

    Molten carbonate fuel cells (MCFC) are being used in decentralised power plants, as they can reform hydrocarbon bound fuels internally, e.g. natural gas with a energy density of 10 kWh/m{sup 3} at standard conditions, and the efficiency of this mode of operation is around 50 %. However in comparison to other fuel cell systems the power density is only 5 kW/m{sup 3}. The power density of a polymerelectrolyte fuel cell (PEFC) is much higher (50 kW/m{sup 3}). These systems can be run with an efficiency of 50 %, too. Therefore they need hydrogen as a fuel, with an energy density of 2,9 kWh/m{sup 3} at standard conditions. Efficiency decreases to 35 to 40% using Methane as fuel, because of the reforming losses. The power density than is 6 kW/m3 and therefore as high as for a MCFC-system. Acombination of MCFC and PEFC, the so called CoCell, offers the following advantages: - A highly energetic, hydrocarbon based fuel can be used, e.g. Methane. - A high electrical efficiency is achieved. - The power density of this system is higher than for a fuel cell with reformer. In the CoCell the MCFC is working as electricity producing reformer for the PEFC. The off heat of the MCFC is used for reforming, whereby hydrogen is available, being utilised further in the power dense PEFC. The reforming capacity of the MCFC is limited by the internal heat balance. If the endothermic reforming consumes more heat than supplied by the material streams and the fuel cell waste heat, the stack cools down. The performance of such a combined fuel cell system has been evaluated in this thesis using the thermodynamic simulation software Aspen. Calculations reducing the utilisation in the MCFC by various heating techniques showed, that additional heat is supplied most efficiently by increasing the current density of the MCFC. Thereby the stack is heated electrically and the power density of the system is increased by the improved power density of the MCFC. The reduction of the utilisation is achieved

  1. Balance Function Disorders

    Science.gov (United States)

    1991-01-01

    Researchers at the Balance Function Laboratory and Clinic at the Minneapolis (MN) Neuroscience Institute on the Abbot Northwestern Hospital Campus are using a rotational chair (technically a "sinusoidal harmonic acceleration system") originally developed by NASA to investigate vestibular (inner ear) function in weightlessness to diagnose and treat patients with balance function disorders. Manufactured by ICS Medical Corporation, Schaumberg, IL, the chair system turns a patient and monitors his or her responses to rotational stimulation.

  2. Compilation of Non-Financial Balances in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Vítězslav Ondruš

    2011-09-01

    Full Text Available The System of National Accounts in the Czech Republic consists of three main parts — institutional sector accounts, input-output tables and balances of non-financial assets. All three parts are compiled interactively by common time schedule. The article deals with balances of non-financial assets and their relation to core institutional sector accounts and explains why the third parallel part of SNA in the Czech Republic was build, describes its weaknesses and future development.

  3. Balances instruments, manufacturers, history

    CERN Document Server

    Robens, Erich; Kiefer, Susanne

    2014-01-01

    The book deals mainly with direct mass determination by means of a conventional balances. It covers the history of the balance from the beginnings in Egypt earlier than 3000 BC to recent developments. All balance types are described with emphasis on scientific balances. Methods of indirect mass determination, which are applied to very light objects like molecules and the basic particles of matter and celestial bodies, are included.  As additional guidance, today’s manufacturers are listed and the profile of important companies is reviewed. Several hundred photographs, reproductions and drawings show instruments and their uses. This book includes commercial weighing instruments for merchandise and raw materials in workshops as well as symbolic weighing in the ancient Egyptian’s ceremony of ‘Weighing of the Heart’, the Greek fate balance, the Roman  Justitia, Juno Moneta and Middle Ages scenes of the Last Judgement with Jesus or St. Michael and of modern balances. The photographs are selected from the...

  4. Authigenic Carbonate and the History of the Global Carbon Cycle

    Science.gov (United States)

    Schrag, Daniel P.; Higgins, John. A.; Macdonald, Francis A.; Johnston, David T.

    2013-02-01

    We present a framework for interpreting the carbon isotopic composition of sedimentary rocks, which in turn requires a fundamental reinterpretation of the carbon cycle and redox budgets over Earth's history. We propose that authigenic carbonate, produced in sediment pore fluids during early diagenesis, has played a major role in the carbon cycle in the past. This sink constitutes a minor component of the carbon isotope mass balance under the modern, high levels of atmospheric oxygen but was much larger in times of low atmospheric O2 or widespread marine anoxia. Waxing and waning of a global authigenic carbonate sink helps to explain extreme carbon isotope variations in the Proterozoic, Paleozoic, and Triassic.

  5. Carbon Stock and Carbon Cycle of Wetland Ecosystem

    Institute of Scientific and Technical Information of China (English)

    Zhangquan; ZENG; Canming; ZHANG; Jiao; LI; Nan; YANG; Xihao; LI; Yandong; NIU; Zijian; WU

    2014-01-01

    Wetland ecosystem is an essential ecosystem in the world. Its organic carbon stock and carbon cycle are important basis of global carbon cycle researches and also major contents of global climate change researches. Researches have shown that wetland protection and restoration can promote carbon accumulation and reduce emission of greenhouse gases. This paper discussed influence of carbon stock and carbon balance of wetland ecosystem and emission of greenhouse gases,as well as the relationship between wetland and global climate changes. Finally,it made prospect on researches about carbon cycle of Dongting Lake.

  6. Reconciling estimates of the contemporary North American carbon balance among terrestrial biosphere models, atmospheric inversions and a new approach for estimating net ecosystem exchange from inventory-based data

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, D. J.; Turner, D. P.; Stinson, Graham; McGuire, A. David; Wei, Yaxing; West, Tristram O.; Heath, L.; deJong, B.; McConkey, Brian; Birdsey, Richard A.; Kurz, Werner; Jacobson, Andy; Huntzinger, Deborah N.; Pan, Y.; Post, W. M.; Cook, R. B.

    2012-04-02

    While fossil fuel emissions are calculated with relatively high precision, understanding the fate of those emissions with respect to sequestration in terrestrial ecosystems requires data and methods that can reduce uncertainties in the diagnosis of land-based CO2 sinks. The wide range in the land surface flux estimates is related to a number of factors, but most generally because of the different methodologies used to develop estimates of carbon stocks and flux, and the uncertainties inherent in each approach. The alternative approaches to estimating continental scale carbon fluxes that we explored here can be broadly classified as applying a top-down or bottom-up perspective. Top-down approaches calculate land-atmosphere carbon fluxes based on atmospheric budgets and inverse modeling. Bottom-up approaches rely primarily on measurements of carbon stock changes (the inventory approach) or on spatially distributed simulations of carbon stocks and/or fluxes using process-based modeling (the forward modelapproach).

  7. Life Cycle Analysis of Carbon Flow and Carbon Footprint of Harvested Wood Products of Larix principis-rupprechtii in China

    Directory of Open Access Journals (Sweden)

    Fei Lun

    2016-03-01

    Full Text Available Larix principis-rupprechtii is a native tree species in North China with a large distribution; and its harvested timbers can be used for producing wood products. This study focused on estimating and comparing carbon flows and carbon footprints of different harvested wood products (HWPs from Larix principis-ruppechtii based on the life cycle analysis (from seedling cultivation to HWP final disposal. Based on our interviews and surveys, the system boundary in this study was divided into three processes: the forestry process, the manufacturing process, and the use and disposal process. By tracking carbon flows of HWPs along the entire life cycle, we found that, for one forest rotation period, a total of 26.81 tC/ha sequestered carbon was transferred into these HWPs, 66.2% of which were still stored in the HWP when the rotation period had ended; however, the HWP carbon storage decreased to 0.25 tC/ha (only 0.9% left in the 100th year after forest plantation. The manufacturing process contributed more than 90% of the total HWP carbon footprint, but it was still smaller than the HWP carbon storage. In terms of the carbon storage and the carbon footprint, construction products had the largest net positive carbon balance compared to furniture and panel products. In addition, HWP are known to have a positive impact on global carbon mitigation because they can store parts of the sequestered carbon for a certain period of time and they have a substitution effect on carbon mitigation. Furthermore, there still exist great opportunities for carbon mitigation from HWPs through the use of cleaner energy and increasing the utilization efficiency of wood fuel.

  8. Carbon cyclist

    Science.gov (United States)

    Showstack, Randy

    A satellite launched in early August as part of NASA's Mission to Planet Earth could dramatically increase understanding of how carbon cycles through the Earth's biosphere and living organisms and how this process influences global climate. The Sea-viewing Wide Field-of-View Sensor (SeaWiFS) will measure the color of the oceans with a radiometer to determine the concentration of chlorophyll found in oceanic phytoplankton. The single-celled plants, at the base of food chains around the world, remove carbon dioxide from seawater through photosynthesis, which allows oceans to absorb more carbon dioxide from the atmosphere.

  9. Water and sodium balance in space

    DEFF Research Database (Denmark)

    Drummer, C; Norsk, P; Heer, M

    2001-01-01

    We have previously shown that fluid balances and body fluid regulation in microgravity (microG) differ from those on Earth (Drummer et al, Eur J Physiol 441:R66-R72, 2000). Arriving in microG leads to a redistribution of body fluid-composed of a shift of fluid to the upper part of the body and an...

  10. Reduction of Iron-Oxide-Carbon Composites: Part II. Rates of Reduction of Composite Pellets in a Rotary Hearth Furnace Simulator

    Science.gov (United States)

    Halder, S.; Fruehan, R. J.

    2008-12-01

    A new ironmaking concept is being proposed that involves the combination of a rotary hearth furnace (RHF) with an iron-bath smelter. The RHF makes use of iron-oxide-carbon composite pellets as the charge material and the final product is direct-reduced iron (DRI) in the solid or molten state. This part of the research includes the development of a reactor that simulated the heat transfer in an RHF. The external heat-transport and high heating rates were simulated by means of infrared (IR) emitting lamps. The reaction rates were measured by analyzing the off-gas and computing both the amount of CO and CO2 generated and the degree of reduction. The reduction times were found to be comparable to the residence times observed in industrial RHFs. Both artificial ferric oxide (PAH) and naturally occurring hematite and taconite ores were used as the sources of iron oxide. Coal char and devolatilized wood charcoal were the reductants. Wood charcoal appeared to be a faster reductant than coal char. However, in the PAH-containing pellets, the reverse was found to be true because of heat-transfer limitations. For the same type of reductant, hematite-containing pellets were observed to reduce faster than taconite-containing pellets because of the development of internal porosity due to cracking and fissure formation during the Fe2O3-to-Fe3O4 transition. This is, however, absent during the reduction of taconite, which is primarily Fe3O4. The PAH-wood-charcoal pellets were found to undergo a significant amount of swelling at low-temperature conditions, which impeded the external heat transport to the lower layers. If the average degree of reduction targeted in an RHF is reduced from 95 to approximately 70 pct by coupling the RHF with a bath smelter, the productivity of the RHF can be enhanced 1.5 to 2 times. The use of a two- or three-layer bed was found to be superior to that of a single layer, for higher productivities.

  11. Selected Basin Characterization Model Parameters for the Great Basin Carbonate and Alluvial Aquifer System of Nevada, Utah, and Parts of Adjacent States

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset was created in support of a study focusing on ground-water resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a...

  12. 1:1,000,000-scale hydrographic areas and flow systems for the Great Basin carbonate and alluvial aquifer system of Nevada, Utah, and parts of adjacent states

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset was created in support of a U.S. Geological Survey (USGS) study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer...

  13. Evapotranspiration units in the Basin and Range carbonate-rock aquifer system, White Pine County, Nevada, and adjacent parts of Nevada and Utah

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Accurate estimates of ground-water discharge are crucial in the development of a water budget for the Basin and Range Carbonate-rock Aquifer System (BARCAS) study...

  14. Three-dimensional hydrogeologic framework for the Great Basin carbonate and alluvial aquifer system of Nevada, Utah, and parts of adjacent states

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset was created in support of a study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer system (GBCAAS). The GBCAAS is a...

  15. 1:1,000,000-scale potentiometric contours and control points for the Great Basin carbonate and alluvial aquifer system of Nevada, Utah, and parts of adjacent states

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset was created in support of a U.S. Geological Survey (USGS) study focusing on groundwater resources in the Great Basin carbonate and alluvial aquifer...

  16. Study on Strain Resistance Effect of Part-stromatolithic Carbon Fiber Cement-base Materials%局部叠层碳纤维水泥基材料的应变电阻效应研究

    Institute of Scientific and Technical Information of China (English)

    郑立霞; 朱四荣; 李卓球; 郑华升

    2011-01-01

    The continuous carbon fiber-bundle was used to replace the chopped carbon fiber in the traditional carbon fiber reinforced concrete. The changing rule of the resistance of three-point-bending beams with the part-stromatolithic carbon fiber cement-based material was studied when they were loaded on monotonous or cyclic tension stress. The strain resistance effect of part-stromatolithic carbon fiber cement-based material was analyzed and compared with that of the continuous carbon fiber cement-based materials. The results showed that the part-stromatolithic carbon fiber cement-based material was near 23 times the gauge factor of the continuous carbon fiber cement-based material, but their stability was worse. The resistance of the part-stromatolithic carbon fiber cement-based material increased along with the increase of tension strain and decreased along with the decrease of tension strain. The part-stromatolithic carbon fiber reinforced cement-based material was expected to performance the health monitoring of the civil engineering structure and infrastructure.%将碳纤维加入普通混凝土中,普通混凝土便成为具有自诊断功能特性的智能混凝土.利用这些功能特性可望实现土木工程结构和基础设施的健康监测.使用连续碳纤维束取代传统碳纤维增强混凝土中的短切碳纤维,研究了局部叠层碳纤维水泥基材料三点弯曲梁在单调和循环拉应力作用下电阻的变化规律,分析了局部叠层碳纤维水泥基材料的应变-电阻效应,并与连续碳纤维水泥基材料应变-电阻效应作了比较.结果表明,局部叠层碳纤维水泥基材料的应变灵敏系数是连续碳纤维水泥基材料应变灵敏系数的近23倍,但稳定性要差一些;局部叠层碳纤维水泥基材料的电阻随着拉伸应变的增大而增大,随着拉伸应变的减小而减小,可望用于土木工程结构和基础设施的健康监测.

  17. Balance Devices Train Golfers for a Consistent Swing

    Science.gov (United States)

    2015-01-01

    As part of the effort to understand the effects of spaceflight on astronauts, NASA funded research that resulted in a commercial product to treat balance disorders. West Palm Beach, Florida-based Sports Therapy Inc. worked with the inventor to modify the technology, creating the Dynamic Balance System (DBS) for sports applications. DBS is now used by Professional Golfers' Association-owned facilities and golf academies to help players achieve an effective, balanced swing.

  18. Ways to improve conceptual aspects of balancing the budget

    Directory of Open Access Journals (Sweden)

    Dodon Svetlana

    2013-02-01

    Full Text Available The aim of the present article is to analyze the various concepts, techniques and procedures applied in different periods by different countries in order to balance state budget. There are analyzed positive parts and deficiencies at legislative level of different concepts concerning budgetary balance and as a result are developed a series of measures that aim to balance the budget of Moldova

  19. El Balance Social en las Empresas

    Directory of Open Access Journals (Sweden)

    Victor R. Sánchez Calvillo

    2001-01-01

    Full Text Available Las empresas mexicanas tienen muchas responsabilidades, mismas que las involucran prácticamente en todos los ámbitos. Tradicionalmente, las empresas mexicanas han asumido únicamente algunas de sus responsabilidades, olvidando por completo las sociales. El concepto de Balance Social no les dice nada. El único balance que conocen es el Balance General contable. Es importante que ahora, con la globalización y la ausencia de fronteras, las empresas mexicanas conozcan lo que es un Balance Social, las partes que lo integran, cómo se elabora y sobre todo, que finalidad es la que cumple. Las empresas mexicanas no podrán estar a la altura de las otras naciones, sobre todo europeas, sino encaran con valentía y determinación sus responsabilidades sociales, las plasman por escrito y dan a conocer, libre, espontánea y honestamente las acciones emprendidas en este ámbito. El Balance Social es un documento tan importante corno el Balance General contable y habrá de ser difundido como este último, para que todos los integrantes de la organización, e incluso agentes externos a la misma, conozcan la política social y humana de las empresas mexicanas.

  20. National forest inventory of Finland and its role estimating the carbon balance forests. COST E21 Workshop. Contribution of forests and forestry to mitigate greenhouse effects. Joensuu (Finland. 28-30 Sep 2000

    Directory of Open Access Journals (Sweden)

    Tomppo E.

    2000-01-01

    Full Text Available The paper presents the total stem volume increment and total drain, as well as the corresponding carbon contents, of the trees of Finnish forests. The carbon contents are converted to carbon dioxide equivalents. The total increment is above stump stem wood volume increment including bark. The estimates come from the National Forest Inventory of Finland conducted by the Finnish Forest Research Institute. The method is briefly described. The total drain includes fellings, i.e. removals and cutting waste, as well as natural mortality of above stump stem wood volume of trees including bark. The above stump stem volumes are converted to total tree biomass, total dry matter and total carbon content using available coefficients.

  1. Atmospheric carbon dioxide and the global carbon cycle

    Energy Technology Data Exchange (ETDEWEB)

    Trabalka, J R [ed.

    1985-12-01

    This state-of-the-art volume presents discussions on the global cycle of carbon, the dynamic balance among global atmospheric CO2 sources and sinks. Separate abstracts have been prepared for the individual papers. (ACR)

  2. Empleo de la cáscara de arroz en la fundición de piezas de acero al carbono//Using of rice husk in the carbon steel casting parts process

    Directory of Open Access Journals (Sweden)

    Juan Carlos Cruz-Pérez

    2012-05-01

    Full Text Available Los materiales auxiliares desempeñan un papel importante en el aumento de la eficiencia tecnológica del proceso de fundición de piezas de acero al carbono. En este artículo se exponen los primeros resultados del empleo de la cáscara de arroz como material termoaislante en la obtención de piezas fundidas de acero al carbono. En los experimentos se evaluó la influencia  de seis combinaciones de las variables espesor de pared del casquillo y capa de cobertura. En la confección de los casquillos se utilizó cáscara de arroz triturada, la que posteriormente fue aglutinada con silicato de sodio, apisonada y endurecida con CO2, mientras que la cobertura se utilizó sin procesamiento previo. El mayor nivel de entrega de acero se obtuvo al emplear un espesor de casquillo de 65 mm y una altura de cobertura de 85 mm. El valor del ASAF generado por las variantes experimentales resultó igual o inferior a 0,48. Palabras claves: casquillo termoaislante, polvo de cobertura, cáscara de arroz, acero fundido.______________________________________________________________________________ Abstract Feeding auxiliary materials perform a very important role in improves technological efficiency of carbon steel casting parts process. In this article are exposing the first results in the rice husk using as an insulating material in such process. The variables sleeve thickness and covering thickness’ influence were evaluated in six combinations by means of experiments. In sleeves preparation was used crushed rice husk, which was agglutinated with sodium silicate, compacted and hardened with CO2, meanwhile as covering it was uses without previous preparation. The mayor liquid steel delivering level was get employing 65 mm sleeve thickness and 85 mm covering thickness. The ASAF value generated for experimental variants was equal or inferior to 0.48. Key words: insulating sleeve, riser sleeve, hot topping, rice husk, steel cast.

  3. Prediction of Enthalpy of Formation in the Solid State (at 298.15 K) using Second-Order Group Contributions. Part 1. Carbon-Hydrogen and Carbon-Hydrogen-Oxygen Compounds

    Science.gov (United States)

    Salmon, Anna; Dalmazzone, Didier

    2006-09-01

    A predictive method, based on Benson's group additivity technique, is developed for calculating the enthalpy of formation in the solid phase, at 298.15K, of carbon-hydrogen compounds and carbon-hydrogen-oxygen compounds. A complete database compiles 398 experimental enthalpies of formation. The whole group contribution values, ring strain corrections, and nonnearest neighbor interactions evaluated are listed. Finally a comparison with Cohen's method indicates that this new estimation method leads to higher precision and reliability.

  4. Equilibration of plain carbon and alloy steels with endothermic carburizing atmospheres: Part II. Oxidation of plain carbon and Armco steels during carburizing at 1000 °C and 1038 °C

    Science.gov (United States)

    Hwang, Jong-Il; Jhee, Tae-Gu; Kim, Young-Kyu; Hwang, Tae-Young

    2010-10-01

    Carbon contents by the weight gain of AISI type 1010 steel foils equilibrated with CO-CO2 mixtures at 1000 °C were 0.03 wt.% to 0.07 wt.% higher than those by chemical analysis at carbon potentials of 0.2 wt.%C to 0.7 wt.%C. The lower the carbon potential, the bigger the difference became. This difference of 0.05 wt.% to 0.08 wt.% was also measured when the same materials were equilibrated with CO-CO2 mixtures at 1038 °C at carbon potentials below 0.4 wt.%C. Oxygen analyses of these equilibrated steel foils confirmed that those differences of 0.03 wt.% to 0.07 wt.% and 0.05 wt.% to 0.08 wt.% were mainly due to the selective oxidation of manganese. When Armco steels and type 1010 steels were equilibrated simultaneously with endothermic-base carburizing atmospheres at 1038 °C, oxidation was negligible and the carbon contents of the both steels were identical at carbon potentials of 0.2 wt.%C to 1.4 wt.%C.

  5. A balanced team generating model

    NARCIS (Netherlands)

    van de Water, Tara; van de Water, Henny; Bukman, Cock

    2007-01-01

    This paper introduces a general team balancing model. It first summarizes existing balancing methods. It is shown that for these methods it is difficult to meet all the conditions posed by Belbin on balanced teams. This mainly is caused by the complexity of the balancing problem. A mathematical mode

  6. Finding Your Balance

    CERN Document Server

    (CCL), Center for Creative Leadership; Patterson, Gordon

    2011-01-01

    Balance isn't an issue of time, but an issue of choice. It's about living your values by aligning your behavior with what you believe is really important. Aligning your behavior with your values is much like any other developmental experience; the basic process involves assessment, challenge, and support. You need to determine where you are, define where you want to go, and then put into place the tools you need to get there.Balance is about more than how you spend your time. It's about how you live your life. It's about recognizing that you have control over the choices you make and aligning