WorldWideScience

Sample records for ci type carbonaceous

  1. Comets as Parent Bodies of CI1 Carbonaceous Meteorites and Possible Habitats of Ice-Microbiota

    Science.gov (United States)

    Wickramasinghe, N. Chandra; Wallis, Daryl H.; Rozanov, Alexei Yu.; Hoover, Richard B.

    2011-01-01

    Recent studies of comets and cometary dust have confirmed the presence of biologically relevant organic molecules along with clay minerals and water ice. It is also now well established by deuterium/hydrogen ratios that the CI1 carbonaceous meteorites contain indigenous extraterrestrial water. The evidence of extensive aqueous alteration of the minerals in these meteorites led to the hypothesis that water-bearing asteroids or comets represent the parent bodies of the CI1 (and perhaps CM2) carbonaceous meteorites. These meteorites have also been shown to possess a diverse array of complex organics and chiral and morphological biomarkers. Stable isotope studies by numerous independent investigators have conclusively established that the complex organics found in these meteorites are both indigenous and extraterrestrial in nature. Although the origin of these organics is still unknown, some researchers have suggested that they originated by unknown abiotic mechanisms and may have played a role in the delivery of chiral biomolecules and the origin of life on Early Earth. In this paper we review these results and investigate the thermal history of comets. We show that permanent as well as transient domains of liquid water can be maintained on a comet under a plausible set of assumptions. With each perihelion passage of a comet volatiles are preferentially released, and during millions of such passages the comet could shed crustal debris that may survive transit through the Earth s atmosphere as a carbonaceous meteorite. We review the current state of knowledge of comets and carbonaceous meteorites. We also present the results of recent studies on the long-term viability of terrestrial ice-microbiota encased in ancient glacial ice and permafrost. We suggest that the conditions which have been observed to prevail on many comets do not preclude either survivability (or even the active metabolism and growth) of many types of eukaryotic and prokaryotic microbial

  2. Structure and Bonding of Carbon in Clays from CI Carbonaceous Chondrites

    Science.gov (United States)

    Garview, Laurence a. J.; Buseck, Peter R.

    2005-01-01

    Carbonaceous chondrites (CC) contain a diverse suite of C-rich materials. Acid dissolution of these meteorites leaves a C-rich residue with chemical and structural affinities to kerogen. This material has primarily been analyzed in bulk, and much information has been provided regarding functional groups and elemental and isotopic compositions. However, comparatively little work has been done on C in unprocessed meteorites. Studies of CCs suggest a spatial relationship of some C-rich materials with products of aqueous alteration. Recent studies revealed discrete submicronsized, C-rich particles in Tagish Lake and a range of CM2 meteorites. A challenge is to correlate the findings from the bulk acid-residue studies with those of high-spatial resolution-mineralogical and spectroscopic observations of unprocessed meteorites. Hence, the relationship between the C-rich materials in the acid residues and its form and locations in the unprocessed meteorite remains unclear. Here we provide information on the structure and bonding of C associated with clays in CI carbonaceous chondrites. Additional information is included in the original extended abstract.

  3. Effects of day-of-week trends and vehicle types on PM2.5-bounded carbonaceous compositions

    International Nuclear Information System (INIS)

    Pongpiachan, Siwatt; Kositanont, Charnwit; Palakun, Jittree; Liu, Suixin; Ho, Kin Fai; Cao, Junji

    2015-01-01

    Carbonaceous compositions of PM 2.5 were measured in the heart of Bangkok from 17th November 2010 to 19th January 2012, and a data set of 94 samples was constructed. Effects of day-of-week trends and vehicle types on PM 2.5 -bound TC, OC, and EC were carefully investigated. In this study, OC was the most important contributor to the total PM 2.5 mass concentration. The average PM 2.5 -bound OC content measured at CHAOS (18.8 ± 9.18 μg m −3 ) was approximately 11 times higher than at Chaumont, Switzerland (1.7 μg m −3 ), but approximately five times lower than at Xi'an, China (93.0 μg m −3 ). The application of diagnostic binary ratios of OC/EC and estimations of secondary organic carbon (SOC) coupled with autocorrelation plots (Box and Jenkins) highlight the enhanced impacts of traffic emissions, especially from diesel vehicles, on PM 2.5 -bound carbonaceous compositions on weekdays relative to weekends. Hierarchical cluster analysis (HCA) coupled with principal component analysis (PCA) underline the importance of diesel emissions as the primary contributors of carbonaceous aerosols, particularly during weekdays. - Highlights: • Traffic emissions play an important role in governing OC and EC during weekdays. • Time series analysis shows the existence of day-of-week trends of OC and EC. • Diesel vehicles are the main contributors of carbonaceous compositions

  4. Effects of day-of-week trends and vehicle types on PM{sub 2.5}-bounded carbonaceous compositions

    Energy Technology Data Exchange (ETDEWEB)

    Pongpiachan, Siwatt, E-mail: pongpiajun@gmail.com [NIDA Center for Research & Development of Disaster Prevention & Management, School of Social and Environmental Development, National Institute of Development Administration (NIDA), 118 Moo 3, Sereethai Road, Klong-Chan, Bangkapi, Bangkok 10240 (Thailand); SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences (IEECAS), Xi' an 710075 (China); Kositanont, Charnwit [Department of Microbiology, Faculty of Sciences, Chulalongkorn University, Bangkok 10330 (Thailand); Palakun, Jittree [Faculty of Education, Valaya Alongkorn Rajabhat University under the Royal Patronage (VRU), No.1 Moo 20, Phaholyothin Road, Klong luang, Pathumthani 13180 (Thailand); Liu, Suixin; Ho, Kin Fai; Cao, Junji [SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences (IEECAS), Xi' an 710075 (China)

    2015-11-01

    Carbonaceous compositions of PM{sub 2.5} were measured in the heart of Bangkok from 17th November 2010 to 19th January 2012, and a data set of 94 samples was constructed. Effects of day-of-week trends and vehicle types on PM{sub 2.5}-bound TC, OC, and EC were carefully investigated. In this study, OC was the most important contributor to the total PM{sub 2.5} mass concentration. The average PM{sub 2.5}-bound OC content measured at CHAOS (18.8 ± 9.18 μg m{sup −3}) was approximately 11 times higher than at Chaumont, Switzerland (1.7 μg m{sup −3}), but approximately five times lower than at Xi'an, China (93.0 μg m{sup −3}). The application of diagnostic binary ratios of OC/EC and estimations of secondary organic carbon (SOC) coupled with autocorrelation plots (Box and Jenkins) highlight the enhanced impacts of traffic emissions, especially from diesel vehicles, on PM{sub 2.5}-bound carbonaceous compositions on weekdays relative to weekends. Hierarchical cluster analysis (HCA) coupled with principal component analysis (PCA) underline the importance of diesel emissions as the primary contributors of carbonaceous aerosols, particularly during weekdays. - Highlights: • Traffic emissions play an important role in governing OC and EC during weekdays. • Time series analysis shows the existence of day-of-week trends of OC and EC. • Diesel vehicles are the main contributors of carbonaceous compositions.

  5. CARBONACEOUS, NITROGENOUS AND PHOSPHORUS MATTERS REMOVAL FROM DOMESTIC WASTEWATER BY AN ACTIVATED SLUDGE REACTOR OF NITRIFICATION-DENITRIFICATION TYPE

    Directory of Open Access Journals (Sweden)

    MOHAMAD ALI FULAZZAKY

    2009-03-01

    Full Text Available This paper proposes an environmental engineering method based on biotechnology approach as one of the expected solutions that should be considered to implementing the activated sludge for improving the quality of water and living environment, especially to remove the major pollutant elements of domestic wastewater. Elimination of 3 major pollutant elements, i.e., carbon, nitrogen and phosphor containing the domestic wastewater is proposed to carry out biological method of an anoxic-aerobic reactor therein these types of pollutants should be consecutively processed in three steps. Firstly, eliminate the carbonaceous matter in the aerobic reactor. Secondly, to remove the carbonaceous and nitrogenous matters, it is necessary to modify the reactor’s nature from the aerobic condition to an anoxic-aerobic reactor. And finally, when the cycle of nitrification-denitrification is stable to achieve the target’s efficiency of reactor by adding the ferric iron into the activated sludge, it can be continued to remove the carbonaceous, nitrogenous and phosphorous matters simultaneously. The efficiency of carbonaceous and nitrogenous matters removal was confirmed with the effluent standard, COD is less than 100 mgO2/L and the value of global nitrogen is less than 10 mgN/L. The effectiveness of suspended matter removal is higher than 90% and the decantation of activated sludge is very good as identifying the Molhman’s index is below of 120 mL/L. The total phosphorus matter removal is more effective than the soluble phosphorus matter. By maintaining the reactor’s nature at the suitable condition, identifying the range of pH between 6.92 and 7.16 therefore the excellent abatement of phosphor of about 80% is achieving with the molar Fe/P ratio of 1.4.

  6. Effect of Inhomogeneous Mixture Properties on CI Combustion in a Schnurle-Type Gasoline DI Engine

    Science.gov (United States)

    Kim, Seok-Woo; Moriyoshi, Yasuo

    The authors have performed experiments on compression-ignition (CI) for a single-cylinder Schnurle-type two-stroke gasoline direct injection (DI) engine which employs a variable exhaust port, area, and deduced two presumptions from the experimental results. Firstly, the spatial distributions of fuel concentration and in-cylinder gas temperature are indispensable to enable CI operation under stratified charge conditions, because CI operation is not possible in a DI system although the necessary conditions of the scavenging efficiency and the in-cylinder gas temperature for the initiation of CI in homogeneous charge conditions are satisfied. Secondly, it is possible that flame propagation occurs in stratified charge CI conditions, because the combustion period in the later stage after 80% mass burned becomes longer than that with homogeneous charge CI combustion. In this report, in order to verify the above two presumptions deduced from experiments, the gas exchange process and mixture formation process were numerically analyzed, and the initiation conditions of CI were estimated using a CHEMKIN application. As a result, in case of CI with a late injection timing in DI system, it was found that CI was possible because high temperature but no fuel region and low temperature but rich fuel region exist in the cylinder due to inhomogeneous spatial distributions of fuel and temperature. Also, in case of CI with a late injection timing, the flame propagation was possible in the low-temperature and diluted rich region. Thereby, the two presumptions deduced from the experimental results were validated from the numerical analysis results.

  7. An review on geology study of carbonaceous-siliceous-pelitic rock type uranium deposit in China and the strategy for its development

    International Nuclear Information System (INIS)

    Zhao Fengmin

    2009-01-01

    Carbonaceous-siliceous-pelitic rock type uranium deposit was founded by Chinese uranium geologist, it refers to the uranium deposit hosted by non or light metamophosed carbonate,siliceous rock, pelitic rock and their intermediates. It is one of the important types uranium deposit in China. A lot of this type deposits have been discovered in China and their temporal-spatial distribution pattern and mineralization features have been basically identified, and the rich experience have layed a good foundation for the future exploration. Although the ore of this type is not favourable economically, it is still available. Because carbonaceous-siliceous-pelitic rock type uranium deposit has great resource potential, metallogenic study and exploration efforts should be projected differentially according to their economic profit so as to meet the uranium resource demand of nuclear power development in China. (authors)

  8. The origin and hydrothermal mobilization of carbonaceous matter associated with Paleoproterozoic orogenic-type gold deposits of West Africa

    Czech Academy of Sciences Publication Activity Database

    Kříbek, B.; Sýkorová, Ivana; Machovič, V.; Knésl, I.; Laufek, F.; Zachariáš, J.

    2015-01-01

    Roč. 270, November 01 (2015), s. 300-317 ISSN 0301-9268 Institutional support: RVO:67985891 Keywords : carbonaceous matter * gold deposits * graphite Subject RIV: DB - Geology ; Mineralogy Impact factor: 4.037, year: 2015

  9. Carbonaceous matter and putative microfossils of the mid-Archean Kromberg type-section re-visited, Barberton Greenstone Belt, South Africa

    Science.gov (United States)

    McLoughlin, Nicola; Grosch, Eugene

    2014-05-01

    grains >30 μm across recording wave-motion on the seafloor. Secondary fabrics include hydrothermal veins containing remobilized carbon and sometimes sulphides, also void-filling silica spherulites coated in carbonaceous matter. A novel fabric discovered in the lower Kromberg chert is silicified carbonaceous fragments with plastic deformation that are morphologically comparable to microtextures reported from the 3.416 Ga Buck Reef Chert (Tice and Lowe 2004) interpreted to be deformed microbial mat fragments. These fabrics are currently being studied by raman spectroscopy to assess the effects of taphonomic processes and metamorphic alteration on this potential biosignature. In-situ sulphur isotope measurements by SIMS on sulphides associated with primary carbonaceous fabrics of the Footbridge chert found a narrow range in δ34SCDTvalues of -6.00 to + 1.50 o and positive Δ33S values up to +2.50 o suggesting the involvement of atmospheric sulphur aerosols, but do not strongly support either microbial sulphate reduction or disproportionation (Grosch and McLoughlin 2013). The geochemical evidence for microbial processes must therefore be further tested in the Kromberg cherts to build upon the bulk carbon isotope data that is consistent with, but alone not diagnostic of, microbial processes. In summary, this new survey of carbonaceous cherts from the Kromberg type section has identified well-preserved candidate microbial microfabrics that will be the target of ongoing high resolution in-situ geochemical and ultrastructure analysis.

  10. In-Situ Oxygen Isotopic Composition of Individual Minerals in Tagish Lake, a Unique Type 2 Carbonaceous Meteorite

    Science.gov (United States)

    Engrand, C.; Gounelle, M.; Duprat, J.; Zolensky, M. E.

    2001-01-01

    We measured the oxygen isotopic composition of individual minerals in Tagish Lake. The relationship with carbonaceous chondrites is confirmed. We found very O-16 enriched olivines. The carbonates will require a dedicated study of their C and O isotopes. Additional information is contained in the original extended abstract.

  11. Ci PERMIT

    CERN Multimedia

    Relations with the Host States Service

    1999-01-01

    The Swiss Permanent Mission to the International Organisations at Geneva recalls that only the spouses and children of members of personnel resident in Switzerland and in possession of a legitimation card of types 'B', 'C', 'D' or 'E' issued by the Swiss Federal Department of Foreign Affairs are entitled to benefit from a Ci Permit.The 'demande d'attestation de permis Ci' (request for a Ci permit attestation) can be sent to the Mission only through Personnel Division (Administrative Services, Office 33/1-025).Additional information on access by family members of CERN officials to the Swiss labour market are available to you on the Web site of the Relations with the Host States Service (cf. document entitled 'Employment in Switzerland for spouses and children of CERN officials' dated March 1996).Relations with the Host States Servicehttp://www.cern.ch/relations/Tel. 72848

  12. Citrus leprosis virus cytoplasmic type 2 (CiLV-C2 detection in Meta and Casanare States

    Directory of Open Access Journals (Sweden)

    Guillermo León

    2014-07-01

    Full Text Available This study discusses the diagnosis and detection of the new citrus leprosis virus cytoplasmic type 2 (CiLV-C2 in samples collected in Meta and Casanare States, using molecular techniques performed RT-PCR on plant tissue and mite vectors Brevipalpus phoenicis (Geijskes. RT-PCR tests were carry out using specific primers MP and CPG. The use of CPG primers allows the detection of CiLV-C2, in tissue plant samples with leprosis symptoms on fruits and leaves of Valencia orange (Citrus sinensis L. and Swinglea gluinosa Merr. leaves, which confirms the presence of this virus in Colombia. The MP primers did not detect the CiLV-C2 in any of performed tests. The RT-PCR technique allows detection of CiLV-C2 in samples of B. phoenicis mite vectors, with the specific CPG primers. Molecular detection of CiLV-C2 by RT-PCR technique is a fundamental tool for the virus diagnosis in Colombia, and should be used in diagnosis and prevention programs of citrus leprosis in the country.

  13. CI Implementation

    DEFF Research Database (Denmark)

    Jørgensen, Frances; Boer, Harry; Laugen, Bjørge Timenes

    2006-01-01

    Continuous Improvement Network Survey and a number of empirical cases described in the literature. While the CI Maturity Model suggests that CI maturation ought to be a linear process, the findings in this article suggest that there are feasible alternatives for companies to develop CI capability.......There are a number of tools available for organizations wishing to measure and subsequently develop Continuous Improvement (CI). In this article, we review and evaluate a well-accepted CI development model, namely the CI Maturity Model (Bessant and Caffyn, 1997), against data collected from the 2nd...

  14. Identification of silicate and carbonaceous presolar grains by SIMS in the type-3 enstatite chondrite ALHA81189

    International Nuclear Information System (INIS)

    Ebata, Shingo; Fagan, Timothy J.; Yurimoto, Hisayoshi

    2008-01-01

    An isotope ratio imaging technique using the HokuDai isotope microscope system has been applied to in situ survey for presolar grains in the type-3 enstatite chondrite ALHA81189. Rastered and static ion beam were used for primary beam. Lateral resolution of the isotope image was achieved to be 0.4 μm for static ion beam mode and to be 0.6 μm for rastered ion beam mode. As a result, the abundances of presolar grains are 150-200% larger under the static ion beam mode than under the rastered ion beam mode. Development of image processing introducing isotopography of 32 S - , 24 Mg 16 O - and 56 Fe - succeeded to increase efficiency of presolar grain characterization. Using the static ion beam and introducing appropriate isotopography were very useful methods of in situ characterization of presolar grains in meteorites

  15. Study of the type of gamma radioactivity in platform carbonaceous rocks: analyses and environmental, diagenetic and geodynamical interpretations

    International Nuclear Information System (INIS)

    Raddadi, Mohamed-Chaker

    2004-01-01

    In well-logging, values of gamma-activity are measured by scintillometry. A conventional paradigm is to link high γ-activity to Potassium (K) and Thorium (Th) isotopes present in clays and to Uranium isotopes present either in detrital sediments (typically in zircon or monazite minerals) or to sediments rich in organic matter. In shallow-water carbonates platforms, high γ-activities are interpreted in the same way. However, in a first γ-scintillometer survey of the Gorges du Nan section (sub-alpine Vercors massif), we found inconsistencies between lithologies and their expected γ-responses: the highest radioactive beds do not correspond to high argillaceous or detrital limestones and marls, but to some low content argillaceous or 'pure' limestones beds. The aim of this study was to identify the radioactive isotopes associated to different types of carbonates, their localisation, their abundance and their respective contribution to the total gamma response in order to propose a new method for the interpretation of gamma-ray logs in shallow-water carbonates. This study was focused on two intervals: - The first one corresponds to the Ba3 depositional sequence (Upper Barremian) which is composed essentially of limestones. This sequence was studied in the Vercors and Chartreuse sub-alpine massifs near Grenoble and in the Swiss Jura near Neuchatel; - The second one corresponds to the 'Lower Oritolina marls' interval. This interval was studied in the Vercors and Chartreuse sub-alpine massifs near Grenoble, in Spain (Organya basin) and in central Tunisia near Kairouan. We carried out detailed sedimentological, diagenetic and isotopic studies of all these sections. Oxygen and carbon stable isotopes analyses allowed us to establish some large scale correlations between sections in the French Alps, in the Pyrenees and in central Tunisia. The good correlation between Oxygen and Carbon stable isotopes curves of the Lower Orbitolina marls in all the

  16. Ukaegbe, CI

    African Journals Online (AJOL)

    Ukaegbe, CI. Vol 11, No 1-2 (2012) - Articles Postpartum Depression Among Igbo Women In An Urban Mission Hospital, South East Nigeria Abstract. ISSN: 1597-1260. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and ...

  17. The Thermal Properties of CM Carbonaceous Chondrites

    Science.gov (United States)

    Britt, D. T.; Opeil, C.

    2017-12-01

    The physical properties of asteroid exploration targets are fundamental parameters for developing models, planning observations, mission operations, reducing operational risk, and interpreting mission results. Until we have returned samples, meteorites represent our "ground truth" for the geological material we expect to interact with, sample, and interpret on the surfaces of asteroids. The physical properties of the volatile-rich carbonaceous chondrites (CI, C2, CM, and CR groups) are of particular interest because of their high resource potential. We have measured the thermal conductivity, heat capacity and thermal expansion of five CM carbonaceous chondrites (Murchison, Murray, Cold Bokkeveld, NWA 7309, Jbilet Winselwan) at low temperatures (5-300 K) to mimic the conditions in the asteroid belt. The mineralogy of these meteorites are dominated by abundant hydrous phyllosilicates, but also contain anhydrous minerals such as olivine and pyroxene found in chondrules. The thermal expansion measurements for all these CMs indicate a substantial increase in meteorite volume as temperature decreases from 230 - 210 K followed by linear contraction below 210 K. Such transitions were unexpected and are not typical for anhydrous carbonaceous chondrites or ordinary chondrites. Our thermal diffusivity results compare well with previous estimates for similar meteorites, where conductivity was derived from diffusivity measurements and modeled heat capacities; our new values are of a higher precision and cover a wider range of temperatures.

  18. CARES: Carbonaceous Aerosol and Radiative Effects Study Science Plan

    Energy Technology Data Exchange (ETDEWEB)

    Zaveri, RA; Shaw, WJ; Cziczo, DJ

    2010-05-27

    Carbonaceous aerosol components, which include black carbon (BC), urban primary organic aerosols (POA), biomass burning aerosols, and secondary organic aerosols (SOA) from both urban and biogenic precursors, have been previously shown to play a major role in the direct and indirect radiative forcing of climate. The primary objective of the CARES 2010 intensive field study is to investigate the evolution of carbonaceous aerosols of different types and their effects on optical and cloud formation properties.

  19. The oxygen isotopic composition of water extracted from carbonaceous chondrites

    OpenAIRE

    Baker, L.; Franchi, Ian; Wright, Ian; Pillinger, Colin

    2001-01-01

    The oxygen isotopic composition of water from carbonaceous chondrites suggests that close to isotopic equilibrium was attained on CI and CM parent bodies. This is more consistent with a closed system than one with fluid flow. Tagish Lake does not display such equilibrium.

  20. TESTING OF CARBONACEOUS ADSORBENTS FOR REMOVAL OF POLLUTANTS FROM WATER

    Directory of Open Access Journals (Sweden)

    RAISA NASTAS

    2012-03-01

    Full Text Available Testing of carbonaceous adsorbents for removal of pollutants from water. Relevant direction for improving of quality of potable water is application of active carbons at various stages of water treatments. This work includes complex research dealing with testing of a broad spectrum of carbonaceous adsorbents for removal of hydrogen sulfide and nitrite ions from water. The role of the surface functional groups of carbonaceous adsorbents, their acid-basic properties, and the influence of the type of impregnated heteroatom (N, O, or metals (Fe, Cu, Ni, on removal of hydrogen sulfide species and nitrite ions have been researched. The efficiency of the catalyst obtained from peach stones by impregnation with Cu2+ ions of oxidized active carbon was established, being recommended for practical purposes to remove the hydrogen sulfide species from the sulfurous ground waters. Comparative analysis of carbonaceous adsorbents reveals the importance of surface chemistry for oxidation of nitrite ions.

  1. Oxygen-isotopic Compositions of Low-FeO relicts in High-FeO Host Chondrules in Acfer 094, a Type 3.0 Carbonaceous Chondrite Closely Related to CM

    Science.gov (United States)

    Rubin, Alan E.; Kunihiro, Tak; Wasson, John T.

    2006-01-01

    With one exception, the low-FeO relict olivine grains within high-FeO porphyritic chondrules in the type 3.0 Acfer 094 carbonaceous chondrite have DELTA O-17 ( = delta O-17 - 0.52 X delta O-18) values that are substantially more negative than those of the high-FeO olivine host materials. These results are similar to observations made earlier on chondrules in C03.0 chondrites and are consistent with two independent models: (1) Nebular solids evolved from low-FeO, low-DELTA O-17 compositions towards high-FeO, more positive DELTA O-17 compositions; and (2) the range of compositions resulted from the mixing of two independently formed components. The two models predict different trajectories on a DELTA O-17 vs. log Fe/Mg (olivine) diagram, but our sample set has too few values at intermediate Fe/Mg ratios to yield a definitive answer. Published data showing that Acfer 094 has higher volatile contents than CO chondrites suggest a closer link to CM chondrites. This is consistent with the high modal matrix abundance in Acfer 094 (49 vol.%). Acfer 094 may be an unaltered CM chondrite or an exceptionally matrix-rich CO chondrite. Chondrules in Acfer 094 and in CO and CM carbonaceous chondrites appear to sample the same population. Textural differences between Acfer 094 and CM chondrites are largely attributable to the high degree of hydrothermal alteration that the CM chondrites experienced in an asteroidal setting.

  2. Microfossils in Carbonaceous Meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2009-01-01

    Microfossils of large filamentous trichomic prokaryotes have been detected during in-situ investigations of carbonaceous meteorites. This research has been carried out using the Field Emission Scanning Electron Microscope (FESEM) to examine freshly fractured interior surfaces of the meteorites. The images obtained reveal that many of these remains are embedded in the meteorite rock matrix. Energy Dispersive X-Ray Spectroscopy (EDS) studies establish that the filamentous microstructures have elemental compositions consistent with the meteorite matrix, but are often encased within carbon-rich electron transparent sheath-like structures infilled with magnesium sulfate. This is consistent with the taphonomic modes of fossilization of cyanobacteria and sulphur bacteria, since the life habits and processes of these microorganisms frequently result in distinctive chemical biosignatures associated with the properties of their cell-walls, trichomes, and the extracellular polymeric substances (EPS) of the sheath. In this paper the evidence for biogenicity presented includes detailed morphological and morphometric data consistent with known characteristics of uniseriate and multiseriate cyanobacteria. Evidence for indigeneity includes the embedded nature of the fossils and elemental compositions inconsistent with modern biocontaminants.

  3. Hydrogenation process for solid carbonaceous materials

    Science.gov (United States)

    Cox, John L.; Wilcox, Wayne A.

    1979-01-01

    Coal or other solid carbonaceous material is contacted with an organic solvent containing both hydrogen and a transition metal catalyst in solution to hydrogenate unsaturated bonds within the carbonaceous material. This benefaction step permits subsequent pyrolysis or hydrogenolysis of the carbonaceous fuel to form gaseous and liquid hydrocarbon products of increased yield and quality.

  4. Comets, Carbonaceous Meteorites, and the Origin of the Biosphere

    Science.gov (United States)

    Hoover, Richard B.

    2007-01-01

    Evidence for indigenous microfossils in carbonaceous meteorites suggests that the paradigm of the endogenous origin of life on Earth should be reconsidered. It is now widely accepted that comets and carbonaceous meteorites played an important role in the delivery of water, organics and life critical biogenic elements to the early Earth and facilitated the origin and evolution of the Earth's Biosphere. However; the detection of embedded microfossils and mats in carbonaceous meteorites implies that comets and meteorites may have played a direct role in the delivery of intact microorganisms and that the Biosphere may extend far into the Cosmos. Recent space observations have found the nuclei of comets to have very low albedos (approx.0.03) and. these jet-black surfaces become very hot (T approx. 400 K) near perihelion. This paper reviews recent observational data-on comets and suggests that liquid water pools could exist in cavities and fissures between the internal ices and rocks and the exterior carbonaceous crust. The presence of light and liquid water near the surface of the nucleus enhances the possibility that comets could harbor prokaryotic extremophiles (e.g., cyanobacteria) capable of growth over a wide range of temperatures. The hypothesis that comets are the parent bodies of the CI1 and the CM2 carbonaceous meteorites is advanced. Electron microscopy images will be presented showing forms interpreted as indigenous-microfossils embedded' in freshly. fractured interior surfaces of the Orgueil (CI1) and Murchison (CM2) meteorites. These forms are consistent in size and morphologies with known morphotypes of all five orders of Cyanobacteriaceae: Energy Dispersive X-ray Spectroscopy (EDS) elemental data shows that the meteoritic forms have anomalous C/O; C/N; and C/S as compared with modern extremophiles and cyanobacteria. These images and spectral data indicate that the clearly biogenic and embedded remains cannot be interpreted as recent biological

  5. Preg-robbing of Gold by Carbonaceous Materials Encountered in ...

    African Journals Online (AJOL)

    Processing of gold from refractory ores containing carbonaceous materials (CM) poses challenges due to the ability of the CM to preg-rob dissolved gold. Depending on the type and maturity of CM encountered, preg-robbing of aurocyanide ion can lead to reduction in gold recovery ranging from a few percentages to more ...

  6. Novel carbonaceous materials for lithium secondary batteries

    Energy Technology Data Exchange (ETDEWEB)

    Sandi, G.; Winans, R.E.; Carrado, K.A.; Johnson, C.S.

    1997-07-01

    Carbonaceous materials have been synthesized using pillared clays (PILCs) as templates. The PILC was loaded with organic materials such as pyrene in the liquid and vapor phase, styrene in the vapor phase, trioxane, ethylene and propylene. The samples were then pyrolyzed at 700 C in an inert atmosphere, followed by dissolution of the inorganic template by conventional demineralization methods. X-ray powder diffraction of the carbons showed broad d{sub 002} peaks in the diffraction pattern, indicative of a disordered or turbostratic system. N{sub 2} BET surface areas of the carbonaceous materials range from 10 to 100 m{sup 2}/g. There is some microporosity (r < 1 nm) in the highest surface area carbons. Most of the surface area, however, comes from a mixture of micro and mesopores with radii of 2--5 nm. Electrochemical studies were performed on these carbons. Button cells were fabricated with capacity- limiting carbon pellets electrodes as the cathode a/nd metallic lithium foil as the anode. Large reversible capacities (up to 850 mAh/g) were achieved for most of the samples. The irreversible capacity loss was less than 180 mAh/g after the first cycle, suggesting that these types of carbon materials are very stable to lithium insertion and de-insertion reactions.

  7. Carbonaceous Matter in Growing Nanoparticles

    Science.gov (United States)

    Johnston, M. V.; Stangl, C. M.; Horan, A. J.

    2015-12-01

    Atmospheric nanoparticles constitute the greatest portion of ambient aerosol loading by number. A major source of atmospheric nanoparticles is new particle formation (NPF), a gas to particle conversion process whereby clusters nucleate from gas phase precursors to form clusters on the order of one or a few nanometers and then grow rapidly to climatically relevant sizes. A substantial fraction of cloud condensation nuclei (CCN) are thought to arise from NPF. In order to better predict the frequency, growth rates, and climatic impacts of NPF, knowledge of the chemical mechanisms by which nucleated nanoparticles grow is needed. The two main contributors to particle growth are (neutralized) sulfate and carbonaceous matter. Particle growth by sulfuric acid condensation is generally well understood, though uncertainty remains about the extent of base neutralization and the relative roles of ammonia and amines. Much less is known about carbonaceous matter, and field measurements suggest that nitrogen-containing species are important. In this presentation, recent work by our group will be described that uses a combination of ambient measurements, laboratory experiments and computational work to study carbonaceous matter in growing nanoparticles. These studies span a range of particle sizes from the initial adsorption of molecules onto a nanometer-size ammonium bisulfate seed cluster to reactions in particles that are large enough to support condensed-phase chemistry.

  8. Extraterrestrial Amino Acids Identified in Metal-Rich CH and CB Carbonaceous Chondrites from Antarctica

    Science.gov (United States)

    Burton, Aaron S.; Elsila, Jamie E.; Hein, Jason E.; Glavin, Daniel P.; Dworkin, Jason P.

    2013-01-01

    Carbonaceous chondrites contain numerous indigenous organic compounds and could have been an important source of prebiotic compounds required for the origin of life on Earth or elsewhere. Extraterrestrial amino acids have been reported in five of the eight groups of carbonaceous chondrites and are most abundant in CI, CM, and CR chondritesbut are also present in the more thermally altered CV and CO chondrites. We report the abundance, distribution, and enantiomeric and isotopic compositions of simple primary amino acids in six metal-rich CH and CB carbonaceous chondrites that have not previously been investigated for amino acids: Allan Hills (ALH) 85085 (CH3), Pecora Escarpment(PCA) 91467 (CH3), Patuxent Range (PAT) 91546 (CH3), MacAlpine Hills (MAC) 02675(CBb), Miller Range (MIL) 05082 (CB), and Miller Range (MIL) 07411 (CB). Amino acid abundances and carbon isotopic values were obtained by using both liquid chromatography time-of-flight mass spectrometry and fluorescence, and gas chromatography isotope ratiomass spectrometry. The (delta D, delta C-13, delta N-15) ratios of multiple amino acids fall outside of the terrestrial range and support their extraterrestrial origin. Extracts of CH chondrites were found to be particularly rich in amino acids (1316 parts per million, ppm) while CB chondrite extracts had much lower abundances (0.22 ppm). The amino acid distributions of the CH and CB chondrites were distinct from the distributions observed in type 2 and 3 CM and CR chondrites and contained elevated levels of beta-, gamma-, and delta-amino acids compared to the corresponding alpha-amino acids, providing evidence that multiple amino acid formation mechanisms were important in CH and CB chondrites.

  9. (Human) Resourcing For CI

    DEFF Research Database (Denmark)

    Jørgensen, Frances; S., Jacob; Kofoed, Lise Busk

    2005-01-01

    challenging in organizations involved in change processes such as Continuous Improvement (CI), as the technical skills traditionally valued are no longer adequate. These companies are faced with the question: “What competencies should our employees possess in order to contribute to our success, given......More and more, the ability to compete in today’s market is viewed as being dependent on human capital. One of the most challenging aspects of human resource management involves supplying the organization with the human capital necessary to fulfill its objectives. This task becomes especially...... the change processes in which we are engaged?” Without a clear picture of the types of competencies required to implement CI, it is impossible for companies to make informed decisions regarding recruitment, hiring, and training of their workforce. The objective of this paper is therefore to define...

  10. Carbonaceous Material in Extraterrestrial Matter

    Science.gov (United States)

    Martins, Zita

    2015-08-01

    Comets, asteroids and their fragments (i.e. meteorite, micrometeorites and interplanetary dust particles (IDPs)) are known to contain carbonaceous material. IDPs have ~10% of carbon by mass [1-3], while both micrometeorites and IDPs contain organic molecules. However, it is not certain whether these molecules are indigenous or terrestrial contamination [4-7]. On the other hand, ultra-carbonaceous Antarctic micrometeorites (UCAMMs) contain 50-80% of carbonaceous material, which is one of the highest organic matter contents detected in an extraterrestrial body [8]. Comets also have several extraterrestrial organic molecules [9, 10], including the simplest amino acid glycine [11]. In addition, the impact-shock of a typical comet ice mixture produces several amino acids from simple precursors [12]. Carbonaceous meteorites contain up to 5wt% of organic carbon [13], which is either locked in an insoluble kerogen-like polymer, or in a rich organic inventory of soluble organic compounds [14-16]. Bulk analysis of the meteoritic soluble organic fraction has revealed a high molecular diversity of tens of thousands of different molecular compositions [17]. The analysis of the carbonaceous content of comets, asteroids and their fragments provides a window into the resources delivered to the early Earth.[1] Brownlee (1985) Ann. Rev. Earth and Plan. Sci. 13, 147. [2] Schramm et al. (1989) Meteoritics 24, 99. [3] Messenger (2002) MAPS 37, 1491. [4] Clemett et al. (1993) Science 262, 721. [5] Brinton et al. (1998) OLEB 28, 413. [6] Flynn (2003) GCA 67, 4791. [7] Matrajt et al. (2004) MAPS 39, 1849. [8] Duprat et al. (2010) Science 328, 742-745. [9] Bockelée-Morvan et al. (2004) in: Comets II. pp. 391-423. [10] Mumma and Charnley (2011) ARAA 49, 471. [11] Elsila et al. (2009) MAPS 44, 1323. [12] Martins et al. (2013) Nature Geoscience 6, 1045. [13] Alexander et al. (2013) GCA 123, 244. [14] Cronin and Chang (1993) in: The Chemistry of Life’s Origin. pp. 209-258. [15] Cody and

  11. Carbonaceous matters in epigenetic uranium deposits associated with zones of layer oxidation

    International Nuclear Information System (INIS)

    Shchetochkin, V.N.; Uspensij, V.A.; Solntseva, L.C.

    1975-01-01

    The paper presents investigations on the carbonaceous substances encountered in uranium deposits of a certain type. A set of methods (IR spectroscopy, ultimate analysis and others) was used to examine the various types of carbonaceous compounds, their composition, structure and geochemistry, and their role in the formation of uranium concentrations. All the carbonaceous substances are divided into two main groups according to their spacial distribution: those syngenetic to the ore-containing sediments; and epigenetic materials introduced into them as a result of the development of an ascending carbon-bitumen process. A considerable similarity was found between the compositions and properties of forms that are known to have no genetic relation to each other, while carbonaceous formations related by a common origin and belonging to the same group are represented by several modifications with different internal structures and compositons. All the carbonaceous compounds of the syngenetic group occur in a random relationships to the uranium mineralization. Nevertheless, the presence of syngenetic carbonaceous substances assists the formation of rich concentrations of uranium. The appearance of epigenetic carbonaceous substances (bitumens) is generally more closely spacially related to zones of development of uranium mineralization. The maximum concentrations of uranium are typical for hard insoluble bitumens. Among the soluble bitumens, the carbonaceous substances - bitumen S - bound in epigenetic materials, are most enriched in uranium (up to px10 -3 %). The role of the bitumens differs in the formation of displaced and primary uranium ores. In the first case, the significance of the bitumens, seems to lie in the reduction of the redox potential of the infiltrated uranium-bearing waters. In the second case, it is possible that a co-migration of uranium and certain types of carbonaceous substance (bitumen S, hard bitumen) took place in reducing (by iron) solutions

  12. Synthetic carbonaceous fuels and feedstocks

    Science.gov (United States)

    Steinberg, Meyer

    1980-01-01

    This invention relates to the use of a three compartment electrolytic cell in the production of synthetic carbonaceous fuels and chemical feedstocks such as gasoline, methane and methanol by electrolyzing an aqueous sodium carbonate/bicarbonate solution, obtained from scrubbing atmospheric carbon dioxide with an aqueous sodium hydroxide solution, whereby the hydrogen generated at the cathode and the carbon dioxide liberated in the center compartment are combined thermocatalytically into methanol and gasoline blends. The oxygen generated at the anode is preferably vented into the atmosphere, and the regenerated sodium hydroxide produced at the cathode is reused for scrubbing the CO.sub.2 from the atmosphere.

  13. Rare-gas-rich separates from carbonaceous chondrites

    Science.gov (United States)

    Reynolds, J. H.; Frick, U.; Neil, J. M.; Phinney, D. L.

    1978-01-01

    This paper describes an analysis of carbon-rich separates prepared by demineralization of colloidal fractions after disaggregation of bulk samples of the type C2 meteorites Murray, Murchison, and Cold Bokkeveld, as well as a methanol colloid extracted from acid-resistant residues of the Allende meteorite (type C3V) obtained by dissolution of most of the minerals in HCl and HF acids. The carbonaceous separates, or lAlates (a coined word designating colloids prepared sometimes before and sometimes after acid treatment), are characterized incompletely and with difficulty. A stepwise heating experiment on a Murray lAlate is discussed which revealed bimodal release of all noble gases, with similar patterns for Ar, Kr, and Xe. Chemical reactions are suggested as the likely mechanism for gas release. The results are shown to support the concept of a carbonaceous gas carrier uniformly present in meteorites of various types.

  14. Bacterial Paleontology and Studies of Carbonaceous Chondrites

    Science.gov (United States)

    Gerasimenko, L. M.; Hoover, Richard B.; Rozanov, Alexei Y.; Zhegallo, E. A.; Zhmur, S. I.

    1999-01-01

    The study of the fossilization processes of modern cyanobacteria provides insights needed to recognize bacterial microfossils. The fossilization of cyanobacteria is discussed and images of recent and fossil bacteria and cyanobacteria from the Early Proterozoic to Neogene carbonaceous rocks (kerites, shungites, and black shales) and phosphorites are provided. These are compared with biomorphic microstructures and possible microfossils encountered in-situ in carbonaceous meteorites.

  15. Explosive Characteristics of Carbonaceous Nanoparticles

    Science.gov (United States)

    Turkevich, Leonid; Fernback, Joseph; Dastidar, Ashok

    2013-03-01

    Explosion testing has been performed on 20 codes of carbonaceous particles. These include SWCNTs (single-walled carbon nanotubes), MWCNTs (multi-walled carbon nanotubes), CNFs (carbon nanofibers), graphene, diamond, fullerene, carbon blacks and graphites. Explosion screening was performed in a 20 L explosion chamber (ASTM E1226-10 protocol), at a (dilute) concentration of 500 g/m3, using a 5 kJ ignition source. Time traces of overpressure were recorded. Samples exhibited overpressures of 5-7 bar, and deflagration index KSt = V1/3 (dp/pt)max ~ 10 - 80 bar-m/s, which places these materials in European Dust Explosion Class St-1 (similar to cotton and wood dust). There was minimal variation between these different materials. The explosive characteristics of these carbonaceous powders are uncorrelated with particle size (BET specific surface area). Additional tests were performed on selected materials to identify minimum explosive concentration [MEC]. These materials exhibit MEC ~ 101 -102 g/m3 (lower than the MEC for coals). The concentration scans confirm that the earlier screening was performed under fuel-rich conditions (i.e. the maximum over-pressure and deflagration index exceed the screening values); e.g. the true fullerene KSt ~ 200 bar-m/s, placing it borderline St-1/St-2. Work supported through the NIOSH Nanotechnology Research Center (NTRC)

  16. Organic Compounds in Carbonaceous Meteorites

    Science.gov (United States)

    Cooper, Grorge

    2001-01-01

    Carbonaceous meteorites are relatively enriched in soluble organic compounds. To date, these compounds provide the only record available to study a range of organic chemical processes in the early Solar System chemistry. The Murchison meteorite is the best-characterized carbonaceous meteorite with respect to organic chemistry. The study of its organic compounds has related principally to aqueous meteorite parent body chemistry and compounds of potential importance for the origin of life. Among the classes of organic compounds found in Murchison are amino acids, amides, carboxylic acids, hydroxy acids, sulfonic acids, phosphonic acids, purines and pyrimidines (Table 1). Compounds such as these were quite likely delivered to the early Earth in asteroids and comets. Until now, polyhydroxylated compounds (polyols), including sugars (polyhydroxy aldehydes or ketones), sugar alcohols, sugar acids, etc., had not been identified in Murchison. Ribose and deoxyribose, five-carbon sugars, are central to the role of contemporary nucleic acids, DNA and RNA. Glycerol, a three-carbon sugar alcohol, is a constituent of all known biological membranes. Due to the relative lability of sugars, some researchers have questioned the lifetime of sugars under the presumed conditions on the early Earth and postulated other (more stable) compounds as constituents of the first replicating molecules. The identification of potential sources and/or formation mechanisms of pre-biotic polyols would add to the understanding of what organic compounds were available, and for what length of time, on the ancient Earth.

  17. First Results of the “Carbonaceous Aerosol in Rome and Environs (CARE” Experiment: Beyond Current Standards for PM10

    Directory of Open Access Journals (Sweden)

    Francesca Costabile

    2017-12-01

    Full Text Available In February 2017 the “Carbonaceous Aerosol in Rome and Environs (CARE” experiment was carried out in downtown Rome to address the following specific questions: what is the color, size, composition, and toxicity of the carbonaceous aerosol in the Mediterranean urban background area of Rome? The motivation of this experiment is the lack of understanding of what aerosol types are responsible for the severe risks to human health posed by particulate matter (PM pollution, and how carbonaceous aerosols influence radiative balance. Physicochemical properties of the carbonaceous aerosol were characterised, and relevant toxicological variables assessed. The aerosol characterisation includes: (i measurements with high time resolution (min to 1–2 h at a fixed location of black carbon (eBC, elemental carbon (EC, organic carbon (OC, particle number size distribution (0.008–10 μ m, major non refractory PM1 components, elemental composition, wavelength-dependent optical properties, and atmospheric turbulence; (ii 24-h measurements of PM10 and PM2.5 mass concentration, water soluble OC and brown carbon (BrC, and levoglucosan; (iii mobile measurements of eBC and size distribution around the study area, with computational fluid dynamics modeling; (iv characterisation of road dust emissions and their EC and OC content. The toxicological assessment includes: (i preliminary evaluation of the potential impact of ultrafine particles on lung epithelia cells (cultured at the air liquid interface and directly exposed to particles; (ii assessment of the oxidative stress induced by carbonaceous aerosols; (iii assessment of particle size dependent number doses deposited in different regions of the human body; (iv PAHs biomonitoring (from the participants into the mobile measurements. The first experimental results of the CARE experiment are presented in this paper. The objective here is to provide baseline levels of carbonaceous aerosols for Rome, and to address

  18. High resolution TEM of chondritic carbonaceous matter: Metamorphic evolution and heterogeneity

    Science.gov (United States)

    Le Guillou, Corentin; Rouzaud, Jean-Noël.; Bonal, Lydie; Quirico, Eric; Derenne, Sylvie; Remusat, Laurent

    2012-03-01

    The insoluble carbonaceous matter from 12 chondrites (CI, CM, CO, CV, EH, and UOC), was characterized by high resolution transmission electron microscopy (HRTEM). Besides ubiquitous nanoglobules, the insoluble organic matter from petrologic type 1 and 2 chondrites and Semarkona (LL 3.0) is composed of a highly disordered polyaromatic component. No structural differences were observed between these IOMs, in agreement with the limited thermal metamorphism they all experienced. In chondrites of petrologic type >3.0, the evolution of the IOM is controlled by the extent of thermal metamorphism. The polyaromatic layers, shorter than 1 nm in petrologic type ≤3.0 chondrites, grow up to sizes between 5 and 10 nm in petrologic type >3.6 chondrites, contributing to the increase of the degree of structural order. In addition, we find rare, but ubiquitous onion-like carbons, which may be the product of nanodiamond graphitization. The insoluble carbonaceous matter of the enstatite chondrite Sahara 97096 (EH 3) is different from the other meteorites studied here. It is more heterogeneous and displays a high abundance of graphitized particles. This may be the result of a mixture between (1) the disordered carbon located in the matrix, and (2) catalytic graphitized phases associated with metal, potentially originating from partial melting events. The structural and nanostructural evolution are similar in all IOMs. This suggests that the structure of the accreted precursors and the parent body conditions of their secondary thermal modifications (temperature, duration, and pressure) were similar. The limited degree of organization of the most metamorphosed IOMs compared with terrestrial rocks submitted to similar temperature suggests that the conditions are not favorable to graphitization processes, due to the chemical nature of the precursor or the lack of confinement pressure.

  19. Organic Chemistry of Carbonaceous Meteorites

    Science.gov (United States)

    Cronin, John R.

    2001-01-01

    Chiral and carbon-isotopic analyses of isovaline have been carried out on numerous samples of the Murchison and one sample of the Murray carbonaceous chondrite. The isovaline was found to be heterogeneous with regard to enantiomeric excess (ee) both between samples and within a single Murchison sample. L-Excesses ranging from 0 to 15% were observed. The isovaline delta(sup 13) C was found to be about +18%. No evidence was obtained suggesting terrestrial contamination in the more abundant L-enantiomer. A correlation was observed between isovaline (also alpha - aminoisobutyric acid) concentration and PCP content of five CM chondrites. It is suggested that isovaline, along with other meteoritic a-methyl amino acids with ee, are of presolar origin. The possible formation of ee in extraterrestrial amino acids by exposure to circularly polarized light or by magnetochiral photochemistry is discussed. Key words: Murchison meteorite, Murray meteorite, amino acids, isovaline, chirality, carbon isotopes, PCP.

  20. Nebula Scale Mixing Between Non-Carbonaceous and Carbonaceous Chondrite Reservoirs: Testing the Grand Tack Model with Almahata Sitta Stones

    Science.gov (United States)

    Yin, Q.-Z.; Sanborn, M. E.; Goodrich, C. A.; Zolensky, M.; Fioretti, A. M.; Shaddad, M.; Kohl, I. E.; Young, E. D.

    2018-01-01

    There is an increasing number of Cr-O-Ti isotope studies that show that solar system materials are divided into two main populations, one carbonaceous chondrite (CC)-like and the other is non-carbonaceous (NCC)-like, with minimal mixing between them attributed to a gap opened in the propoplanetary disk due to Jupiter's formation. The Grand Tack model suggests that there should be a particular time in the disk history when this gap is breached and ensuring a subsequent large-scale mixing between S- and C-type asteroids (inner solar system and outer solar system materials), an idea supported by our recent work on chondrule (Delta)17O-(epsilon)54Cr isotope systematics.

  1. Distinct Purine Distribution in Carbonaceous Chondrites

    Science.gov (United States)

    Callahan, Michael P.; Smith, Karen E.; Cleaves, Henderson J.; Ruzicka, Josef; Stern, Jennifer C.; Glavin, Daniel P.; House, Christopher H.; Dworkin, Jason P.

    2011-01-01

    Carbonaceous chondrite meteorites are known to contain a diverse suite of organic compounds, many of which are essential components of biochemistry. Amino acids, which are the monomers of proteins, have been extensively studied in such meteorites (e.g. Botta and Bada 2002; Pizzarello et aI., 2006). The origin of amino acids in meteorites has been firmly established as extraterrestrial based on their detection typically as racemic mixtures of amino acids, the presence of many non-protein amino acids, and non-terrestrial values for compound-specific deuterium, carbon, and nitrogen isotopic measurements. In contrast to amino acids, nucleobases in meteorites have been far less studied. Nucleobases are substituted one-ring (pyrimidine) or two-ring (purine) nitrogen heterocyclic compounds and serve as the information carriers of nucleic acids and in numerous coenzymes. All of the purines (adenine, guanine, hypoxanthine, and xanthine) and pyrimidines (uracil) previously reported in meteorites are biologically common and could be interpreted as the result of terrestrial contamination (e.g. van del' Velden and Schwartz, 1974.) Unlike other meteoritic organics, there have been no observations of stochastic molecular diversity of purines and pyrimidines in meteorites, which has been a criterion for establishing extraterrestrial origin. Maltins et al. (2008) performed compound-specific stable carbon isotope measurements for uracil and xanthine in the Murchison meteorite. They assigned a non-terrestrial origin for these nucleobases; however, the possibility that interfering indigenous molecules (e.g. carboxylic acids) contributed to the 13C-enriched isotope values for these nucleobases cannot be completely ruled out. Thus, the origin of these meteoritic nucleobases has never been established unequivocally. Here we report on our investigation of extracts of II different carbonaceous chondrites covering various petrographic types (Cl, CM, and CR) and degrees of aqueous alteration

  2. Thermal alteration in carbonaceous chondrites and implications for sublimation in rock comets

    Science.gov (United States)

    Springmann, Alessondra; Lauretta, Dante S.; Steckloff, Jordan K.

    2015-11-01

    Rock comets are small solar system bodies in Sun-skirting orbits (perihelion q shower, is the only rock comet currently known to periodically eject dust and form a coma. Thermal fracturing or thermal decomposition of surface materials may be driving Phaethon’s cometary activity (Li & Jewitt, 2013). Phaethon-like asteroids have dynamically unstable orbits, and their perihelia can change rapidly over their ~10 Myr lifetimes (de León et al., 2010), raising the possibility that other asteroids may have been rock comets in the past. Here, we propose using spectroscopic observations of mercury (Hg) as a tracer of an asteroid’s thermal metamorphic history, and therefore as a constraint on its minimum achieved perihelion distance.B-class asteroids such as Phaethon have an initial composition similar to aqueously altered primitive meteorites such as CI- or CM-type meteorites (Clark et al., 2010). Laboratory heating experiments of ~mm sized samples of carbonaceous chondrite meteorites from 300K to 1200K at a rate of 15K/minute show mobilization and volatilization of various labile elements at temperatures that could be reached by Mercury-crossing asteroids. Samples became rapidly depleted in labile elements and, in particular, lost ~75% of their Hg content when heated from ~500-700 K, which corresponds to heliocentric distances of ~0.15-0.3 au, consistent with our thermal models. Mercury has strong emission lines in the UV (~ 185 nm) and thus its presence (or absence) relative to carbonaceous chondrite abundances would indicate if these bodies had perihelia in their dynamical histories inside of 0.15 AU, and therefore may have previously been Phaethon-like rock comets. Future space telescopes or balloon-borne observing platforms equipped with a UV spectrometer could potentially detect the presence or absence of strong ultraviolet mercury lines on rock comets or rock comet candidates.

  3. 'Indicator'carbonaceous phyllite/graphitic schist in the Archean ...

    Indian Academy of Sciences (India)

    Carbonaceous rocks in the form of graphitic schist and carbonaceous phyllite are the major host rocks of the gold mineralization in Kundarkocha gold deposit of the Precambrian Singhbhum orogenic belt in eastern India. The detection of organic carbon, essentially in the carbonaceous phyllite and graphitized schist within ...

  4. Exposure ages of carbonaceous chondrites, 1

    Science.gov (United States)

    Nishiizumi, K.; Arnold, J. R.; Caffee, M. W.; Finkel, R. C.; Southon, J. R.; Nagai, H.; Honda, M.; Sharma, P.; Imamura, M.; Kobayashi, K.

    1993-01-01

    The recent exposure histories of carbonaceous chondrites have been investigated using cosmogenic radionuclides. Our results may indicate a clustering of exposure ages of C1 and C2 chondrites into two peaks, 0.2 My and 0.6 My, perhaps implying two collisional events of Earth-crossing parent bodies. Among carbonaceous chondrites are some having short exposure ages which Mazor et al. hypothesized cluster into a small number of families. This hypothesis is based on spallogenic Ne-21 exposure ages, which in some instances are difficult to determine owing to the large amounts of trapped noble gases in carbonaceous chondrites. Also, since Ne-21 is stable, it integrates a sample's entire exposure history, so meteorites with complex exposure histories are difficult to understand using exclusively Ne-21. Cosmogenic radionuclides provide an alternative means of determining the recent cosmic ray exposure duration. To test the hypothesis of Mazor et al. we have begun a systematic investigation of exposure histories of Antarctic and non-Antarctic carbonaceous chondrites especially C2s.

  5. Microfossils of filamentous prokaryotes in CI1 and CM2 meteorites

    Science.gov (United States)

    Hoover, Richard B.

    2008-08-01

    Field Emission Scanning Electron Microscopy (FESEM) studies of recently obtained samples of Orgueil, Ivuna and Murchison meteorites have provided further evidence for the existence of indigenous filamentous microfossils embedded in the mineral matrix of CI1 and CM2 carbonaceous meteorites. Energy Dispersive X-ray Spectroscopy (EDS) spot data and 2-D elemental X-ray maps establish that the nitrogen and sulphur content of the forms found in the meteorites are dramatically different from modern prokaryotic and eukaryotic cells. These results are interpreted as providing additional evidence for the existence of a complex suite of indigenous microfossils in carbonaceous meteorites.

  6. Laboratory Studies Of Circumstellar Carbonaceous Grain Formation

    Science.gov (United States)

    Contreras, Cesar; Sciamma-O'Brien, Ella; Salama, Farid

    2014-06-01

    The study of the formation processes of dust is essential to understand the budget of extraterrestrial organic molecules. Although dust with all its components plays an important role in the evolution of interstellar (IS) chemistry and in the formation of organic molecules, little is known on the formation processes of carbonaceous dust. We report the progress that was recently achieved in this domain using NASA Ames’ COSmIC facility (Contreras & Salama 2013, ApJS, 208, 6). PAHs are important chemical building blocks of IS dust. They are detected in IDPs and in meteoritic samples. Additionally, observational, laboratory, and theoretical studies have shown that PAHs are an important, ubiquitous component of the ISM. The formation of PAHs from smaller molecules has not been extensively studied. Therefore, we have performed laboratory experiments to study the dynamic processes of carbon grain formation, starting from the smallest hydrocarbon molecules into the formation of larger PAH and further into nanograins. Studies of IS dust analogs formed from a variety of PAH and hydrocarbon precursors as well as species that include the atoms O, N, and S, have recently been performed in our laboratory using the COSmIC facility to provide conditions that simulate IS and circumstellar environments. The species formed in the COSmiC chamber through a pulsed discharge nozzle plasma source are detected and characterized with a cavity ringdown spectrometer coupled to a time-of-flight mass spectrometer, thus providing both spectroscopic and ion mass information in-situ. Analysis of solid soot particles was also conducted using scanning electron microscopy at the UCSC/NASA Ames’ MACS facility. The SEM analysis of the deposition of soot from methane and acetylene precursors seeded in argon plasmas provide examples on the types of nanoparticles and micrograins that are produced in these gas mixtures under our experimental conditions. From these measurements, we derive information on

  7. Baking process of thin plate carbonaceous compact

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Yoshio; Shimada, Toyokazu

    1987-06-27

    As a production process of a thin plate carbonaceous compact for separator of phosphoric acid fuel cell, there is a process to knead carbonaceous powder and thermosetting resin solution, to form and harden the kneaded material and then to bake, carbonize and graphitize it. However in this baking and carbonization treatment, many thin plate compacts are set in a compiled manner within a heating furnace and receive a heat treatment from their circumference. Since the above compacts to be heated tend generally to be heated from their peripheries, their baked conditions are not homogeneous easily causing the formation of cracks, etc.. As a process to heat and bake homogeneously by removing the above problematical points, this invention offers a process to set in a heating furnace a laminate consisting of the lamination of thin plate carbonaceous compacts and the heat resistant soaking plates which hold the upper and lower ends of the above lamination, to fill the upper and under peripheries of the laminate above with high heat conductive packing material and its side periphery with low heat conductive packing material respectively and to heat and sinter it. In addition, the invention specifies the high and low heat conductive packing materials respectively. (1 fig, 2 tabs)

  8. Chemical analysis of organic molecules in carbonaceous meteorites

    OpenAIRE

    Torrao Pinto Martins, Zita Carla

    2007-01-01

    Meteorites are extraterrestrial objects that survive the passage through the Earth’s atmosphere and impact the Earth's surface. They can be divided into several classes, the carbonaceous chondrites being one of them. Carbonaceous chondrites are the oldest and best preserved meteorites and contain a record of the birth of the solar system. They are rich in carbon, containing up to 3 wt% of organic carbon. Carbonaceous chondrites have a rich organic inventory that includes, among others, amino ...

  9. Carbonaceous Asteroid Volatile Recovery (CAVoR) system, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The Carbonaceous Asteroid Volatile Recovery (CAVoR) system extracts water and volatile organic compounds for propellant production, life support consumables, and...

  10. Acritarchs in carbonaceous meteorites and terrestrial rocks

    Science.gov (United States)

    Rozanov, Alexei Y.; Hoover, Richard B.

    2013-10-01

    Acritarchs are a group of organic-walled, acid-resistant microfossils of uncertain or unknown origin. Some are thought to represent the cysts or resting stages of unicellular protists (possibly dinoflagellates), chrysophytes (green algae) or other planktonic eukaryotic algae. Acritarchs are found throughout the geologic column extending back as far at 3.2 Ga. The presence of large sphaeromorphs in the Archaean provides evidence that the eukaryotic lineage extends much farther back in time than previously thought possible. Acritarchs are abundant in the Paleoproterozoic shales (1.9-1.6 Ga) of the former Soviet Union and they have been extensively used for the investigation of Proterozoic and Paleozoic biostratigraphy and paleoenvironmental parameters. Scanning Electron Microscope studies have revealed the fossilized remains of organic-walled microfossils of unknown origin and exhibiting characteristics of acritarchs in a variety of carbonaceous meteorites. In many cases, these remains are black or brown in color and have Carbon/Oxygen ratios suggesting they have been diagenetically converted into kerogen. It is not feasible that the fossilized remains of organicwalled microfossils such as acritarchs represent biological contaminant that invaded and became embedded in the rock matrix of carbonaceous meteorites within the short time periods of their residence on Earth. Consequently, these groups of microfossils are considered to provide an additional line for the existence of indigenous extraterrestrial microbial remains in meteorites. This paper presents a brief review of acritarchs in terrestrial rocks and provides images of a number of similar morphotypes of uncertain origin found in freshly fractured samples of carbonaceous meteorites.

  11. New Tendencies in Development of Carbonaceous Additives for Welding Fluxes

    International Nuclear Information System (INIS)

    Kozyrev, N A; Kryukov, R E; Kozyreva, O A

    2015-01-01

    The paper provides results of comparative analysis of the effect of carbonaceous components introduced into welding fluxes on molten metal - slag interaction. Thermodynamical calculations of dehydrogenization are presented for submerged arc welding. A positive influence of carbonaceous additives on gas content and mechanical properties of welds is demonstrated. Carbon and fluorine containing additives are emphasized to be promising for automatic submerged arc welding. (paper)

  12. Chemical analysis of organic molecules in carbonaceous meteorites

    NARCIS (Netherlands)

    Torrao Pinto Martins, Zita Carla

    2007-01-01

    Meteorites are extraterrestrial objects that survive the passage through the Earth’s atmosphere and impact the Earth's surface. They can be divided into several classes, the carbonaceous chondrites being one of them. Carbonaceous chondrites are the oldest and best preserved meteorites and contain a

  13. Aqueous processing of organic compounds in carbonaceous asteroids

    Science.gov (United States)

    Trigo-Rodríguez, Josep Maria; Rimola, Albert; Martins, Zita

    2015-04-01

    There is growing evidence pointing towards a prebiotic synthesis of complex organic species in water-rich undifferentiated bodies. For instance, clays have been found to be associated with complex organic compounds (Pearson et al. 2002; Garvie & Buseck 2007; Arteaga et al. 2010), whereas theoretical calculations have studied the interaction between the organic species and surface minerals (Rimola et al., 2013) as well as surface-induced reactions (Rimola at al. 2007). Now, we are using more detailed analytical techniques to study the possible processing of organic molecules associated with the mild aqueous alteration in CR, CM and CI chondrites. To learn more about these processes we are studying carbonaceous chondrites at Ultra High-Resolution Transmission Electron Microscopy (UHR-TEM). We are particularly interested in the relationship between organics and clay minerals in carbonaceous chondrites (CCs) matrixes (Trigo-Rodríguez et al. 2014, 2015).We want to address two goals: i) identifying the chemical steps in which the organic molecules could have increased their complexity (i.e., surface interaction and catalysis); and ii) studying if the organic matter present in CCs experienced significant processing concomitant to the formation of clays and other minerals at the time in which these planetary bodies experienced aqueous alteration. Here, these two points are preliminarily explored combing experimental results with theoretical calculations based on accurate quantum mechanical methods. References Arteaga O, Canillas A, Crusats J, El-Hachemi Z, Jellison GE, Llorca J, Ribó JM (2010) Chiral biases in solids by effect of shear gradients: a speculation on the deterministic origin of biological homochirality. Orig Life Evol Biosph 40:27-40. Garvie LAJ, Buseck PR (2007) Prebiotic carbon in clays from Orgueil and Ivuna (CI) and Tagish lake (C2 ungrouped) meteorites. Meteorit Planet Sci 42:2111-2117. Pearson VK, Sephton MA, Kearsley AT, Bland AP, Franchi IA, Gilmour

  14. The Spatial Distribution of Organic Matter and Mineralogical Relationships in Carbonaceous Chondrites

    Science.gov (United States)

    Clemett, S. J.; Messenger, S.; Thomas-Keprta, K. L.; Nakamura-Messenger, K.

    2012-01-01

    Organic matter present within primitive carbonaceous meteorites represents the complex conglomeration of species formed in a variety of physically and temporally distinct environments including circumstellar space, the interstellar medium, the Solar Nebula & Jovian sub-nebulae and asteroids. In each case, multiple chemical pathways would have been available for the synthesis of organic molecules. Consequently these meteorites constitute a unique record of organic chemical evolution in the Universe and one of the biggest challenges in organic cosmochemistry has been in deciphering this record. While bulk chemical analysis has provided a detailed description of the range and diversity of organic species present in carbonaceous chondrites, there is virtually no hard experimental data as to how these species are spatially distributed and their relationship to the host mineral matrix, (with one exception). The distribution of organic phases is nevertheless critical to understanding parent body processes. The CM and CI chondrites all display evidence of low temperature (bodies. This pervasive aqueous alteration may have led to aqueous geochromatographic separation of organics and synthesis of new organics coupled to aqueous mineral alteration. To address such issues we have applied the technique of microprobe two-step laser desorption / photoionization mass spectrometry (L2MS) to map in situ the spatial distribution of a broad range of organic species at the micron scale in the freshly exposed matrices of the Bells, Tagish Lake and Murchison (CM2) carbonaceous chondrites.

  15. Global cloud condensation nuclei influenced by carbonaceous combustion aerosol

    Directory of Open Access Journals (Sweden)

    D. V. Spracklen

    2011-09-01

    Full Text Available Black carbon in carbonaceous combustion aerosol warms the climate by absorbing solar radiation, meaning reductions in black carbon emissions are often perceived as an attractive global warming mitigation option. However, carbonaceous combustion aerosol can also act as cloud condensation nuclei (CCN so they also cool the climate by increasing cloud albedo. The net radiative effect of carbonaceous combustion aerosol is uncertain because their contribution to CCN has not been evaluated on the global scale. By combining extensive observations of CCN concentrations with the GLOMAP global aerosol model, we find that the model is biased low (normalised mean bias = −77 % unless carbonaceous combustion aerosol act as CCN. We show that carbonaceous combustion aerosol accounts for more than half (52–64 % of global CCN with the range due to uncertainty in the emitted size distribution of carbonaceous combustion particles. The model predicts that wildfire and pollution (fossil fuel and biofuel carbonaceous combustion aerosol causes a global mean cloud albedo aerosol indirect effect of −0.34 W m−2, with stronger cooling if we assume smaller particle emission size. We calculate that carbonaceous combustion aerosol from pollution sources cause a global mean aerosol indirect effect of −0.23 W m−2. The small size of carbonaceous combustion particles from fossil fuel sources means that whilst pollution sources account for only one-third of the emitted mass they cause two-thirds of the cloud albedo aerosol indirect effect that is due to carbonaceous combustion aerosol. This cooling effect must be accounted for, along with other cloud effects not studied here, to ensure that black carbon emissions controls that reduce the high number concentrations of fossil fuel particles have the desired net effect on climate.

  16. Ion Irradiation Experiments on the Murchison CM2 Carbonaceous Chondrite: Simulating Space Weathering of Primitive Asteroids

    Science.gov (United States)

    Keller, L. P.; Christoffersen, R.; Dukes, C. A.; Baragiola, R. A.; Rahman, Z.

    2015-01-01

    Remote sensing observations show that space weathering processes affect all airless bodies in the Solar System to some degree. Sample analyses and lab experiments provide insights into the chemical, spectroscopic and mineralogic effects of space weathering and aid in the interpretation of remote- sensing data. For example, analyses of particles returned from the S-type asteroid Itokawa by the Hayabusa mission revealed that space-weathering on that body was dominated by interactions with the solar wind acting on LL ordinary chondrite-like materials [1, 2]. Understanding and predicting how the surface regoliths of primitive carbonaceous asteroids respond to space weathering processes is important for future sample return missions (Hayabusa 2 and OSIRIS-REx) that are targeting objects of this type. Here, we report the results of our preliminary ion irradiation experiments on a hydrated carbonaceous chondrite with emphasis on microstructural and infrared spectral changes.

  17. Oxygen Isotopic Compositions of Olivine and Pyroxene from CI Chondrites

    Science.gov (United States)

    Leshin, L. A.; Rubin, A. E.; McKeegan, K. D.

    1996-03-01

    The oxygen isotopic compositions of carbonaceous chondrites are complicated since individual components of these meteorites have distinct isotopic compositions that have been affected, to varying degrees, by both nebular and parent body processes. We present the first measurements of oxygen isotopic compositions of rare olivine and pyroxene in the CI chondrites. By combining these data with oxygen isotopic analyses of secondary minerals in these rocks previously reported by Clayton and co-workers, we hope to place quantitative constraints on the physical processes that occurred during formation of these meteorites. The oxygen isotopic composition of separated olivine and pyroxene grains from Orgueil and Ivuna were measured using SIMS. The delta ^(18)O values of the olivines range from ~+3 to +13 and the delta^(17)O values range from ~+1 to +7. The delta^(18)O values of the pyroxenes range from ~+4 to +10 and the delta^(17)O values range from ~+2 to +5. Observations that will be explained in the interpretation of the data are: (1) CI pyroxene and olivine grains have essentially identical oxygen isotopic compositions which are distinct from those measured in other carbonaceous chondrites. (2) All data points except two are indistinguishable from terrestrial values at the one sigma level, and the two exceptions fall only slightly below the terrestrial fractionation line. We consider the data taken as a whole to be consistent with terrestrial values, as well as the slightly positive delta^(17)O values reported previously for matrix and magnetite in CI chondrites. (3) Due to the small range in d values observed relative to the uncertainties, it is not possible to distinguish whether these data fall on a line of approximately slope 1 or slope 1/2.

  18. Photolytic process for gasification of carbonaceous material

    International Nuclear Information System (INIS)

    Zenty, S.

    1979-01-01

    Process and apparatus are disclosed for converting carbon dioxide to carbon monoxide by subjecting the carbon dioxide to radiation in the presence of carbonaceous material such as coal to form carbon monoxide. The preferred form of radiation is solar energy, and the process is preferably carried out in an atmosphere essentially free of oxygen. The invention also includes subjecting carbon monoxide to radiation to form purified carbon and useful heat energy. The two procedures can be combined into a single process for converting solar or other energy into useful thermal energy with the production of useful products. The reactor apparatus is specifically designed to carry out the radiation-induced conversions. Coal can be desulfurized and its caking characteristics altered by solar radiation in the presence of suitable gases. 3 figures

  19. Methods of ultimate carbonaceous BOD determination

    Science.gov (United States)

    Stamer, J.K.; McKenzie, S.W.; Cherry, R.N.

    1979-01-01

    Studies were conducted to provide an accurate and practical technique for determining the concentration of ultimate carbonaceous biochemical oxygen demand and the rate at which this demand is exerted. The three methods evaluated were carbon derived, nitrification adjusted, and nitrification inhibited. The studies indicate that comparable concentrations and reaction rates can be determined from either non-nitrified samples using no chemical nitrifying inhibitor, or from partially nitrified samples using the chemical inhibitors, 1-allyl-2 thiourea or nitrapyrin, and that the combined use of time-series analysis and Lee's graphical method provide a reliable and accurate technique for determining ultimate biochemical oxygen demand concentration and reaction rate in 5 to 7 days.

  20. Tuneable porous carbonaceous materials from renewable resources.

    Science.gov (United States)

    White, Robin J; Budarin, Vitaly; Luque, Rafael; Clark, James H; Macquarrie, Duncan J

    2009-12-01

    Porous carbon materials are ubiquitous with a wide range of technologically important applications, including separation science, heterogeneous catalyst supports, water purification filters, stationary phase materials, as well as the developing future areas of energy generation and storage applications. Hard template routes to ordered mesoporous carbons are well established, but whilst offering different mesoscopic textural phases, the surface of the material is difficult to chemically post-modify and processing is energy, resource and step intensive. The production of carbon materials from biomass (i.e. sugars or polysaccharides) is a relatively new but rapidly expanding research area. In this tutorial review, we compare and contrast recently reported routes to the preparation of porous carbon materials derived from renewable resources, with examples of our previously reported mesoporous polysaccharide-derived "Starbon" carbonaceous material technology.

  1. Carbonaceous chondrites and the origin of life

    Science.gov (United States)

    Hartman, Hyman; Sweeney, Michael A.; Kropp, Michael A.; Lewis, John S.

    1993-01-01

    Organic matter in carbonaceous chondrites can be separated into three fractions. The first component, the fraction that is insoluble in chloroform and methanol, has a part which is of interstellar origin. The other two fractions (chloroform-soluble hydrocarbons and methanol-soluble polar organics) are hypothesized to have been synthesized on a planetoid body. We propose that the polar organics, i.e., amino acids, were synthesized close to its surface by the radiolysis of hydrocarbons and ammonium carbonate in a liquid water environment. Some hydrocarbons may have been synthesized by a Fischer-Tropsch mechanism in the interior of the body. Ferrous ion acted as a protection against back reactions. The simultaneous synthesis of iron-rich clays with the polar organics may be indicative of events related to the origin of life on Earth.

  2. Crystallography of Magnetite Plaquettes and their Significance as Asymmetric Catalysts for the Synthesis of Chiral Organics in Carbonaceous Chondrites

    Science.gov (United States)

    Chan, Q. H. S.; Zolensky, M. E.

    2015-01-01

    We have previously observed the magnetite plaquettes in carbonaceous chondrites using scanning electron microscope (SEM) imaging, examined the crystal orientation of the polished surfaces of magnetite plaquettes in CI Orgueil using electron backscattered diffraction (EBSD) analysis, and concluded that these magnetite plaquettes are likely naturally asymmetric materials. In this study, we expanded our EBSD observation to other magnetite plaquettes in Orgueil, and further examined the internal structure of these remarkable crystals with the use of X-ray computed microtomography.

  3. Method of distributing liquefaction catalysts in solid carbonaceous material

    Energy Technology Data Exchange (ETDEWEB)

    Weller, S W

    1984-05-23

    A method of dispersing a liquefaction catalyst within coal or other carbonaceous solids involves providing a suspension in oil of microcapsules containing the catalyst. An aqueous solution of a catalytic metal salt is emulsified in the water-immiscible oil and the resulting minute droplets microencapsulated in polymeric shells by interfacial polycondensation. The catalyst is subsequently blended and dispersed throughout the powdered carbonaceous material to be liquefied. At liquefaction temperatures the polymeric microcapsules are destroyed and the catalyst converted to minute crystallites in intimate contact with the carbonaceous material. 2 tables.

  4. Compositions and taxonomy of 15 unusual carbonaceous chondrites

    Science.gov (United States)

    Choe, Won Hie; Huber, Heinz; Rubin, Alan E.; Kallemeyn, Gregory W.; Wasson, John T.

    2010-04-01

    We used instrumental neutron activation analysis and petrography to determine bulk and phase compositions and textural characteristics of 15 carbonaceous chondrites of uncertain classification: Acfer 094 (type 3.0, ungrouped CM-related); Belgica-7904 (mildly metamorphosed, anomalous, CM-like chondrite, possibly a member of a new grouplet that includes Wisconsin Range (WIS) 91600, Dhofar 225, and Yamato-86720); Dar al Gani (DaG) 055 and its paired specimen DaG 056 (anomalous, reduced CV3-like); DaG 978 (type 3 ungrouped); Dominion Range 03238 (anomalous, magnetite-rich CO3.1); Elephant Moraine 90043 (anomalous, magnetite-bearing CO3); Graves Nunataks 98025 (type 2 or type 3 ungrouped); Grosvenor Mountains (GRO) 95566 (anomalous CM2 with a low degree of aqueous alteration); Hammadah al Hamra (HaH) 073 (type 4 ungrouped, possibly related to the Coolidge-Loongana [C-L] 001 grouplet); Lewis Cliff (LEW) 85311 (anomalous CM2 with a low degree of aqueous alteration); Northwest Africa 1152 (anomalous CV3); Pecora Escarpment (PCA) 91008 (anomalous, metamorphosed CM); Queen Alexandra Range 99038 (type 2 ungrouped); Sahara 00182 (type 3 ungrouped, possibly related to HaH 073 and/or to C-L 001); and WIS 91600 (mildly metamorphosed, anomalous, CM-like chondrite, possibly a member of a new grouplet that includes Belgica-7904, Dhofar 225, and Y-86720). Many of these meteorites show fractionated abundance patterns, especially among the volatile elements. Impact volatilization and dehydration as well as elemental transport caused by terrestrial weathering are probably responsible for most of these compositional anomalies. The metamorphosed CM chondrites comprise two distinct clusters on the basis of their Δ17O values: approximately -4‰ for PCA 91008, GRO 95566, DaG 978, and LEW 85311, and approximately 0‰ for Belgica-7904 and WIS 91600. These six meteorites must have been derived from different asteroidal regions.

  5. Carbonaceous Asteroid Volatile Recovery (CAVoR) system, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Carbonaceous Asteroid Volatile Recovery (CAVoR) system produces water and hydrogen-rich syngas for propellant production, life support consumables, and...

  6. Bacterial morphologies in carbonaceous meteorites and comet dust

    OpenAIRE

    Wickramasinghe, N. Chandra; Wallis, Max K.; Gibson, Carl H.; Wallis, Jamie; Al-Mufti, Shirwan; Miyake, Nori

    2010-01-01

    Three decades ago the first convincing evidence of microbial fossils in carbonaceous chondrites was discovered and reported by Hans Dieter Pflug and his collaborators. In addition to morphology, other data, notably laser mass spectroscopy, confirmed the identification of such structures as putative bacterial fossils. Balloon-borne cryosampling of the stratosphere enables recovery of fragile cometary dust aggregates with their structure and carbonaceous matter largely intact. Scanning electron...

  7. Carbonaceous aerosols in Norwegian urban areas

    Directory of Open Access Journals (Sweden)

    K. E. Yttri

    2009-03-01

    Full Text Available Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM10 and PM2.5 concentrations of elemental carbon (EC, organic carbon (OC, water-insoluble organic carbon (WINSOC, and water-soluble organic carbon (WSOC are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by volatile and semivolatile OC. Analyses were performed using the thermal optical transmission (TOT instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan.

    Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OCp at the suburban site was equal to (for PM10 or even higher (for PM2.5 than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m−3. This finding indicates that exposure to primary combustion derived OCp could be equally high in residential areas as in a city center. It is demonstrated that OCp from wood burning (OCwood accounted for almost all OCp at the suburban site in winter, allowing a new estimate of the ratio TCp/levoglucosan for both PM10 and PM2.5. Particulate carbonaceous material (PCM

  8. Mixing state of aerosols and direct observation of carbonaceous and marine coatings on African dust by individual particle analysis

    Science.gov (United States)

    Deboudt, Karine; Flament, Pascal; ChoëL, Marie; Gloter, Alexandre; Sobanska, Sophie; Colliex, Christian

    2010-12-01

    The mixing state of aerosols collected at M'Bour, Senegal, during the Special Observing Period conducted in January-February 2006 (SOP-0) of the African Monsoon Multidisciplinary Analysis project (AMMA), was studied by individual particle analysis. The sampling location on the Atlantic coast is particularly adapted for studying the mixing state of tropospheric aerosols since it is (1) located on the path of Saharan dust plumes transported westward over the northern tropical Atlantic, (2) influenced by biomass burning events particularly frequent from December to March, and (3) strongly influenced by anthropogenic emissions from polluted African cities. Particle size, morphology, and chemical composition were determined for 12,672 particles using scanning electron microscopy (automated SEM-EDX). Complementary analyses were performed using transmission electron microscopy combined with electron energy loss spectrometry (TEM-EELS) and Raman microspectrometry. Mineral dust and carbonaceous and marine compounds were predominantly found externally mixed, i.e., not present together in the same particles. Binary internally mixed particles, i.e., dust/carbonaceous, carbonaceous/marine, and dust/marine mixtures, accounted for a significant fraction of analyzed particles (from 10.5% to 46.5%). Western Sahara was identified as the main source of mineral dust. Two major types of carbonaceous particles were identified: "tar balls" probably coming from biomass burning emissions and soot from anthropogenic emissions. Regarding binary internally mixed particles, marine and carbonaceous compounds generally formed a coating on mineral dust particles. The carbonaceous coating observed at the particle scale on African dust was evidenced by the combined use of elemental and molecular microanalysis techniques, with the identification of an amorphous rather than crystallized carbon structure.

  9. Distribution of aliphatic amines in CO, CV, and CK carbonaceous chondrites and relation to mineralogy and processing history

    Science.gov (United States)

    Aponte, José C.; Abreu, Neyda M.; Glavin, Daniel P.; Dworkin, Jason P.; Elsila, Jamie E.

    2017-12-01

    The analysis of water-soluble organic compounds in meteorites provides valuable insights into the prebiotic synthesis of organic matter and the processes that occurred during the formation of the solar system. We investigated the concentration of aliphatic monoamines present in hot acid water extracts of the unaltered Antarctic carbonaceous chondrites, Dominion Range (DOM) 08006 (CO3) and Miller Range (MIL) 05013 (CO3), and the thermally altered meteorites, Allende (CV3), LAP 02206 (CV3), GRA 06101 (CV3), Allan Hills (ALH) 85002 (CK4), and EET 92002 (CK5). We have also reviewed and assessed the petrologic characteristics of the meteorites studied here to evaluate the effects of asteroidal processing on the abundance and molecular distributions of monoamines. The CO3, CV3, CK4, and CK5 meteorites studied here contain total concentrations of amines ranging from 1.2 to 4.0 nmol g-1 of meteorite; these amounts are 1-3 orders of magnitude below those observed in carbonaceous chondrites from the CI, CM, and CR groups. The low-amine abundances for CV and CK chondrites may be related to their extensive degree of thermal metamorphism and/or to their low original amine content. Although the CO3 meteorites, DOM 08006 and MIL 05013, do not show signs of thermal and aqueous alteration, their monoamine contents are comparable to those observed in moderately/extensively thermally altered CV3, CK4, and CK5 carbonaceous chondrites. The low content of monoamines in pristine CO carbonaceous chondrites suggests that the initial amounts, and not asteroidal processes, play a dominant role in the content of monoamines in carbonaceous chondrites. The primary monoamines, methylamine, ethylamine, and n-propylamine constitute the most abundant amines in the CO3, CV3, CK4, and CK5 meteorites studied here. Contrary to the predominance of n-ω-amino acid isomers in CO3 and thermally altered meteorites, there appears to be no preference for the larger n-amines.

  10. A dual origin for water in carbonaceous asteroids revealed by CM chondrites

    Science.gov (United States)

    Piani, Laurette; Yurimoto, Hisayoshi; Remusat, Laurent

    2018-04-01

    Carbonaceous asteroids represent the principal source of water in the inner Solar System and might correspond to the main contributors for the delivery of water to Earth. Hydrogen isotopes in water-bearing primitive meteorites, for example carbonaceous chondrites, constitute a unique tool for deciphering the sources of water reservoirs at the time of asteroid formation. However, fine-scale isotopic measurements are required to unravel the effects of parent-body processes on the pre-accretion isotopic distributions. Here, we report in situ micrometre-scale analyses of hydrogen isotopes in six CM-type carbonaceous chondrites, revealing a dominant deuterium-poor water component (δD = -350 ± 40‰) mixed with deuterium-rich organic matter. We suggest that this deuterium-poor water corresponds to a ubiquitous water reservoir in the inner protoplanetary disk. A deuterium-rich water signature has been preserved in the least altered part of the Paris chondrite (δDParis ≥ -69 ± 163‰) in hydrated phases possibly present in the CM rock before alteration. The presence of the deuterium-enriched water signature in Paris might indicate that transfers of ice from the outer to the inner Solar System were significant within the first million years of the history of the Solar System.

  11. A dual origin for water in carbonaceous asteroids revealed by CM chondrites

    Science.gov (United States)

    Piani, Laurette; Yurimoto, Hisayoshi; Remusat, Laurent

    2018-03-01

    Carbonaceous asteroids represent the principal source of water in the inner Solar System and might correspond to the main contributors for the delivery of water to Earth. Hydrogen isotopes in water-bearing primitive meteorites, for example carbonaceous chondrites, constitute a unique tool for deciphering the sources of water reservoirs at the time of asteroid formation. However, fine-scale isotopic measurements are required to unravel the effects of parent-body processes on the pre-accretion isotopic distributions. Here, we report in situ micrometre-scale analyses of hydrogen isotopes in six CM-type carbonaceous chondrites, revealing a dominant deuterium-poor water component (δD = -350 ± 40‰) mixed with deuterium-rich organic matter. We suggest that this deuterium-poor water corresponds to a ubiquitous water reservoir in the inner protoplanetary disk. A deuterium-rich water signature has been preserved in the least altered part of the Paris chondrite (δDParis ≥ -69 ± 163‰) in hydrated phases possibly present in the CM rock before alteration. The presence of the deuterium-enriched water signature in Paris might indicate that transfers of ice from the outer to the inner Solar System were significant within the first million years of the history of the Solar System.

  12. C-H activation on rhodium: reaction mechanism and the role of carbonaceous residues

    International Nuclear Information System (INIS)

    Cogen, J.M.; Maier, W.F.

    1986-01-01

    Evidence for two C-H activation mechanisms, the oxidative addition of a single C-H bond and the concerted oxidative addition of two adjacent C-H bonds, is presented. The two mechanisms show different sensitivity to surface structure or particle size. While the first process (E/sub a/ ∼ 21 kcal/mol) is insensitive to the hydrocarbon structure, the second process (E/sub a/ ∼ 5-9 kcal/mol) is sensitive to the hydrocarbon structure. C-H activation is found to be 0.6 order in hexane and zero order in deuterium, which is consistent with oxidative addition as the rate-determining step. The d 2 maximum obtained by H/D exchange of linear alkanes on Rh results from surface olefins, as indicated by high-resolution deuterium NMR. Evidence against the participation of carbonaceous residues in the H/D exchange process is presented, indicating that carbonaceous material is not part of the active site. Two types of carbonaceous residues are detected. One forms at lower temperatures and does not interfere with the reaction; the other forms at higher temperatures and acts to poison the catalyst

  13. Investigation of Pyridine Carboxylic Acids in CM2 Carbonaceous Chondrites: Potential Precursor Molecules for Ancient Coenzymes

    Science.gov (United States)

    Smith, Karen E.; Callahan, Michael P.; Gerakines, Perry A.; Dworkin, Jason P.; House, Christopher H.

    2014-01-01

    The distribution and abundances of pyridine carboxylic acids (including nicotinic acid) in eight CM2 carbonaceous chondrites (ALH 85013, DOM 03183, DOM 08003, EET 96016, LAP 02333, LAP 02336, LEW 85311, and WIS 91600) were investigated by liquid chromatography coupled to UV detection and high resolution Orbitrap mass spectrometry. We find that pyridine monocarboxylic acids are prevalent in CM2-type chondrites and their abundance negatively correlates with the degree of pre-terrestrial aqueous alteration that the meteorite parent body experienced. We also report the first detection of pyridine dicarboxylic acids in carbonaceous chondrites. Additionally, we carried out laboratory studies of proton-irradiated pyridine in carbon dioxide-rich ices (a 1:1 mixture) to serve as a model of the interstellar ice chemistry that may have led to the synthesis of pyridine carboxylic acids. Analysis of the irradiated ice residue shows that a comparable suite of pyridine mono- and dicarboxylic acids was produced, although aqueous alteration may still play a role in the synthesis (and ultimate yield) of these compounds in carbonaceous meteorites. Nicotinic acid is a precursor to nicotinamide adenine dinucleotide, a likely ancient molecule used in cellular metabolism in all of life, and its common occurrence in CM2 chondrites may indicate that meteorites may have been a source of molecules for the emergence of more complex coenzymes on the early Earth.

  14. Carbonaceous species emitted from handheld two-stroke engines

    Science.gov (United States)

    Volckens, John; Olson, David A.; Hays, Michael D.

    Small, handheld two-stroke engines used for lawn and garden work (e.g., string trimmers, leaf blowers, etc.) can emit a variety of potentially toxic carbonaceous air pollutants. Yet, the emissions effluents from these machines go largely uncharacterized, constraining the proper development of human exposure estimates, emissions inventories, and climate and air quality models. This study samples and evaluates chemical pollutant emissions from the dynamometer testing of six small, handheld spark-ignition engines—model years 1998-2002. Four oil-gas blends were tested in each engine in duplicate. Emissions of carbon dioxide, carbon monoxide, and gas-phase hydrocarbons were predominant, and the PM emitted was organic matter primarily. An ANOVA model determined that engine type and control tier contributed significantly to emissions variations across all identified compound classes; whereas fuel blend was an insignificant variable accounting for engines were generally intermediate in magnitude compared with other gasoline-powered engines, numerous compounds traditionally viewed as motor vehicle markers are also present in small engine emissions in similar relative proportions. Given that small, handheld two-stroke engines used for lawn and garden work account for 5-10% of total US emissions of CO, CO 2, NO x, HC, and PM 2.5, source apportionment models and human exposure studies need to consider the effect of these small engines on ambient concentrations in air polluted environments.

  15. Hydrogasification of various carbonaceous sources using pressure change properties

    Energy Technology Data Exchange (ETDEWEB)

    Cha, W.S.; Baek, I.H.; Jang, H.T. [Kunsan National University, Kunsan (Republic of Korea)

    2007-05-15

    Hydrogasification experiments were carried out in a batch reactor capable of operating at 800{sup o}C and 8 MPa. Carbonaceous matters used in the experiments were bituminous and anthracite coal and sawdust. It was found that the decreasing rate of hydrogen gas pressure was closely related to the rate of gas production. This result was confirmed by the change of char conversion. The methane content in the gas products and char conversion rose with the increase of temperature and pressure. The addition of water activated the hydrogasification reaction until the proper level of water amount (up to 30 wt%), but an excess level of water inhibited the reaction. The activation energy of bituminous coal and sawdust char obtained by the Arrhenius plot was 187 KJ/mole and 77 KJ/mole, respectively. In case of loading of catalysts, all catalysts loaded to the char did not give a positive effect in hydrogasification, but the catalytic effect depended on type of catalyst metals and char. In the present hydrogasification of bituminous coal and sawdust, the order of activities for the catalysts tested was K{sub 2}CO{sub 3} does not satisfy NaCO{sub 3} {gt} Fe(NO{sub 3}{sup 2}){gt} Ni(NO{sub 3}{sup 2}){gt} FeSO{sub 4}.

  16. Carbonaceous species in atmospheric aerosols from the Krakow area (Malopolska District: carbonaceous species dry deposition analysis

    Directory of Open Access Journals (Sweden)

    Szramowiat Katarzyna

    2016-01-01

    Full Text Available Organic and elemental carbon content in PM10 was studied at three sites in Malopolska District representing the city centre (Krakow, rural/residential (Bialka and residential/industrial environments (Krakow. The PM10 samples were collected during the winter time study. The highest concentrations of carbonaceous species were observed in Skawina (36.9 μg·m-3 of OC and 9.6 μg·m-3 of EC. The lowest OC and EC concentrations were reported in Krakow (15.2 μg·m-3 and 3.9 μg·m-3, respectively. The highest concentration of carbonaceous species and the highest wind velocities in Skawina influenced the highest values of the dry deposition fluxes. Correlations between OC, EC and chemical constituents and meteorological parameters suggest that a Krakow was influenced by local emission sources and temperature inversion occurrence; b Bialka was under the influence of local emission sources and long-range transport of particles; c Skawina was impacted by local emission sources.

  17. The carbonaceous concrete based on sawdust

    Directory of Open Access Journals (Sweden)

    BELOUSOVA Elena Sergeevna

    2015-06-01

    Full Text Available Today there are many requirements for strength, ecology and economy of produced concretes. The authors of the paper study attenuation of electromagnetic radiation of carbonaceous powders in the concrete composition. Carbon black was selected as a carbon powder for addition in concrete composition. Carbon black is a nanomaterial with disoriented structure of particles (average size is about 50 nm. The composition of the carbon black contains at least 90 wt.% amorphous carbon, more than 5 wt. % chemisorbed oxygen and about 4 wt.% of impurities. Materials with the addition of carbon black have electrical conductivity due to the high content of carbon. These materials are able to absorb electromagnetic radiation. For cement composition with addition of carbon black (more than 30 wt. % and water transmission coefficient of electromagnetic radiation is about –10 dB, for cement composition with 20 wt. % of carbon black the reflection coefficient is –8 dB in the frequency range 8–12 GHz. The concretes with a saturated aqueous solution of calcium chloride and 10% of carbon black possess minimal reflection coefficient (–14... –8 dB. Electromagnetic radiation shielding of concrete with the addition of sawdust was investigated. The concrete with sawdust (40 wt. % impregnated with an aqueous solution with carbon black has the reflection coefficient less than –8 dB and transmission coefficient –40 dB in the frequency range 8–12 GHz. These concretes can be used for creation of a shielded room with the technical equipment for information processing to prevent data leakage through the compromising emanations and crosstalk.

  18. Effect of Z1/2, EH5, and Ci1 deep defects on the performance of n-type 4H-SiC epitaxial layers Schottky detectors: Alpha spectroscopy and deep level transient spectroscopy studies

    Science.gov (United States)

    Mannan, Mohammad A.; Chaudhuri, Sandeep K.; Nguyen, Khai V.; Mandal, Krishna C.

    2014-06-01

    Spectroscopic performance of Schottky barrier alpha particle detectors fabricated on 50 μm thick n-type 4H-SiC epitaxial layers containing Z1/2, EH5, and Ci1 deep levels were investigated. The device performance was evaluated on the basis of junction current/capacitance characterization and alpha pulse-height spectroscopy. Capacitance mode deep level transient spectroscopy revealed the presence of the above-mentioned deep levels along with two shallow level defects related to titanium impurities (Ti(h) and Ti(c)) and an unidentified deep electron trap located at 2.4 eV below the conduction band minimum, which is being reported for the first time. The concentration of the lifetime killer Z1/2 defects was found to be 1.7 × 1013 cm-3. The charge transport and collection efficiency results obtained from the alpha particle pulse-height spectroscopy were interpreted using a drift-diffusion charge transport model. Based on these investigations, the physics behind the correlation of the detector properties viz., energy resolution and charge collection efficiency, the junction properties like uniformity in barrier-height, leakage current, and effective doping concentration, and the presence of defects has been discussed in details. The studies also revealed that the dominating contribution to the charge collection efficiency was due to the diffusion of charge carriers generated in the neutral region of the detector. The 10 mm2 large area detectors demonstrated an impressive energy resolution of 1.8% for 5486 keV alpha particles at an optimized operating reverse bias of 130 V.

  19. Analyzing the Chemical and Spectral Effects of Pulsed Laser Irradiation to Simulate Space Weathering of a Carbonaceous Chondrite

    Science.gov (United States)

    Thompson, M. S.; Keller, L. P.; Christoffersen, R.; Loeffler, M. J.; Morris, R. V.; Graff, T. G.; Rahman, Z.

    2017-01-01

    Space weathering processes alter the chemical composition, microstructure, and spectral characteristics of material on the surfaces of airless bodies. The mechanisms driving space weathering include solar wind irradiation and the melting, vaporization and recondensation effects associated with micrometeorite impacts e.g., [1]. While much work has been done to understand space weathering of lunar and ordinary chondritic materials, the effects of these processes on hydrated carbonaceous chondrites is poorly understood. Analysis of space weathering of carbonaceous materials will be critical for understanding the nature of samples returned by upcoming missions targeting primitive, organic-rich bodies (e.g., OSIRIS-REx and Hayabusa 2). Recent experiments have shown the spectral properties of carbonaceous materials and associated minerals are altered by simulated weathering events e.g., [2-5]. However, the resulting type of alteration i.e., reddening vs. bluing of the reflectance spectrum, is not consistent across all experiments [2-5]. In addition, the microstructural and crystal chemical effects of many of these experiments have not been well characterized, making it difficult to attribute spectral changes to specific mineralogical or chemical changes in the samples. Here we report results of a pulsed laser irradiation experiment on a chip of the Murchison CM2 carbonaceous chondrite to simulate micrometeorite impact processing.

  20. Pulmonary exposure to carbonaceous nanomaterials and sperm quality

    DEFF Research Database (Denmark)

    Skovmand, Astrid; Lauvas, Anna Jacobsen; Christensen, Preben

    2018-01-01

    Background: Semen quality parameters are potentially affected by nanomaterials in several ways: Inhaled nanosized particles are potent inducers of pulmonary inflammation, leading to the release of inflammatory mediators. Small amounts of particles may translocate from the lungs into the lung...... inflammation is a potential modulator of endocrine function. The aim of this study was to investigate the effects of pulmonary exposure to carbonaceous nanomaterials on sperm quality parameters in an experimental mouse model.Methods: Effects on sperm quality after pulmonary inflammation induced by carbonaceous...... nanomaterials were investigated by intratracheally instilling sexually mature male NMRI mice with four different carbonaceous nanomaterials dispersed in nanopure water: graphene oxide (18 mu g/mouse/i.t.), Flammruss 101, Printex 90 and SRM1650b (0.1 mg/mouse/i.t. each) weekly for seven consecutive weeks...

  1. Pyrolysis of carbonaceous materials with solvent quench recovery

    Science.gov (United States)

    Green, Norman W.; Duraiswamy, Kandaswamy; Lumpkin, Robert E.; Knell, Everett W.; Mirza, Zia I.; Winter, Bruce L.

    1978-04-18

    In a continuous process for recovery of values contained in a solid carbonaceous material, the carbonaceous material is comminuted and then subjected to flash pyrolysis in the presence of a particulate heat source to form a pyrolysis product stream containing a carbon containing solid residue and volatilized hydrocarbons. After the carbon containing solid residue is separated from the pyrolysis product stream, values are obtained by condensing volatilized hydrocarbons. The particulate source of heat is formed by oxidizing carbon in the solid residue. Apparatus useful for practicing this process are disclosed.

  2. Modeling and analytical simulation of a smouldering carbonaceous ...

    African Journals Online (AJOL)

    Modeling and analytical simulation of a smouldering carbonaceous rod. A.A. Mohammed, R.O. Olayiwola, M Eseyin, A.A. Wachin. Abstract. Modeling of pyrolysis and combustion in a smouldering fuel bed requires the solution of flow, heat and mass transfer through porous media. This paper presents an analytical method ...

  3. Fungal-Transformation of Surrogate Sulphides and Carbonaceous ...

    African Journals Online (AJOL)

    In the recovery of gold from refractory gold ores, pretreatment is required to decompose sulphides and liberate occluded gold before cyanidation, and to deactivate carbonaceous matter and prevent it from adsorbing dissolved gold. Until the past three decades, most commercial pretreatment processes had been by abiotic ...

  4. Fungal-Transformation of Surrogate Sulphides and Carbonaceous ...

    African Journals Online (AJOL)

    Michael

    2017-12-02

    Dec 2, 2017 ... and Carbonaceous Matter in Refractory Gold Ores: Revisited”, Ghana Mining Journal, Vol. 17, No. .... At the end of biooxidation, gold may be totally ..... In work done by Konadu et al. (2016) on biotransformation of powdered activated carbon (PAC) using enzymes of P. chrysosporium, the authors recorded.

  5. Surfactant-assisted liquefaction of particulate carbonaceous substances

    Science.gov (United States)

    Hsu, G. C. (Inventor)

    1978-01-01

    A slurry of carbonaceous particles such as coal containing an oil soluble polar substituted oleophilic surfactant, suitably an amine substituted long chain hydrocarbon, is liquefied at high temperature and high hydrogen presence. The pressure of surfactant results in an increase in yield and the conversion product contains a higher proportion of light and heavy oils and less asphaltene than products from other liquefaction processes.

  6. Room-Temperature Synthesis of Carbonaceous Films of Defined Thickness

    Czech Academy of Sciences Publication Activity Database

    Kavan, Ladislav; Micka, Karel; Hlavatý, Jaromír

    2004-01-01

    Roč. 16, - (2004), s. 4043-4049 ISSN 0897-4756 R&D Projects: GA AV ČR IAA4040306; GA AV ČR KSK4040110 Keywords : carbonaceous films * liquid amalgam * alkali metal Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.103, year: 2004

  7. Carbonaceous alumina films deposited by MOCVD from aluminium ...

    Indian Academy of Sciences (India)

    Spectroscopic ellipsometry was used to characterize carbonaceous, crystalline aluminium oxide films grown on Si(100) by low-pressure metal organic chemical vapour deposition, using aluminium acetylacetonate as the precursor. The presence of carbon in the films, attribured to the use of a metalorganic precursor for the ...

  8. Ordered mixed-layer structures in the Mighei carbonaceous chondrite matrix

    Science.gov (United States)

    Mackinnon, I. D. R.

    1982-01-01

    High resolution transmission electron microscopy of the Mighei carbonaceous chondrite matrix has revealed the presence of a new mixed layer structure material. This mixed-layer material consists of an ordered arrangement of serpentine-type (S) and brucite-type (B) layers in the sequence SBBSBB. Electron diffraction and imaging techniques show that the basal periodicity is approximately 17 A. Discrete crystals of SBB-type material are typically curved, of small size (less than 1 micron) and show structural variations similar to the serpentine group minerals. Mixed-layer material also occurs in association with planar serpentine. Characteristics of SBB-type material are not consistent with known terrestrial mixed-layer clay minerals. Evidence for formation by a condensation event or by subsequent alteration of pre-existing material is not yet apparent.

  9. catfish, ci.arias anguillaris

    African Journals Online (AJOL)

    BSN

    lean weight gain per day of 0.4 and 0.235g were recorded for diploid gynogens and.. ol r-e~ctively in 42 days. INTRODUCTION. Gynogenesis is a type of parthenogenesis triggered by a geneucall~ mer. ~rmatozoa. For many fish species, ... accelerating the rate of inbreeding or production of clones. All female progemes are ...

  10. Origin and abundance of water in carbonaceous asteroids

    Science.gov (United States)

    Marrocchi, Yves; Bekaert, David V.; Piani, Laurette

    2018-01-01

    The origin and abundance of water accreted by carbonaceous asteroids remains underconstrained, but would provide important information on the dynamic of the protoplanetary disk. Here we report the in situ oxygen isotopic compositions of aqueously formed fayalite grains in the Kaba and Mokoia CV chondrites. CV chondrite bulk, matrix and fayalite O-isotopic compositions define the mass-independent continuous trend (δ17O = 0.84 ± 0.03 × δ18O - 4.25 ± 0.1), which shows that the main process controlling the O-isotopic composition of the CV chondrite parent body is related to isotopic exchange between 16O-rich anhydrous silicates and 17O- and 18O-rich fluid. Similar isotopic behaviors observed in CM, CR and CO chondrites demonstrate the ubiquitous nature of O-isotopic exchange as the main physical process in establishing the O-isotopic features of carbonaceous chondrites, regardless of their alteration degree. Based on these results, we developed a new approach to estimate the abundance of water accreted by carbonaceous chondrites (quantified by the water/rock ratio) with CM (0.3-0.4) ≥ CR (0.1-0.4) ≥ CV (0.1-0.2) > CO (0.01-0.10). The low water/rock ratios and the O-isotopic characteristics of secondary minerals in carbonaceous chondrites indicate they (i) formed in the main asteroid belt and (ii) accreted a locally derived (inner Solar System) water formed near the snowline by condensation from the gas phase. Such results imply low influx of D- and 17O- and 18O-rich water ice grains from the outer part of the Solar System. The latter is likely due to the presence of a Jupiter-induced gap in the protoplanetary disk that limited the inward drift of outer Solar System material at the exception of particles with size lower than 150 μm such as presolar grains. Among carbonaceous chondrites, CV chondrites show O-isotopic features suggesting potential contribution of 17-18O-rich water that may be related to their older accretion relative to other hydrated

  11. Evolution of carbonaceous chondrite parent bodies: Insights into cometary nuclei

    International Nuclear Information System (INIS)

    McSween, H.Y. Jr.

    1989-01-01

    It is thought that cometary samples will comprise the most primitive materials that are able to be sampled. Although parent body alteration of such samples would not necessarily detract from scientists' interest in them, the possibility exists that modification processes may have affected cometary nuclei. Inferences about the kinds of modifications that might be encountered can be drawn from data on the evolution of carbonaceous chondrite parent bodies. Observations suggest that, of all the classes of chondrites, these meteorites are most applicable to the study of comets. If the proportion of possible internal heat sources such as Al-26 in cometary materials are similar to those in chondrites, and if the time scale of comet accretion was fast enough to permit incorporation of live radionuclides, comets might have had early thermal histories somewhat like those of carbonaceous chondrite parent bodies

  12. Pulmonary exposure to carbonaceous nanomaterials and sperm quality

    DEFF Research Database (Denmark)

    Skovmand, Astrid; Lauvas, Anna Jacobsen; Christensen, Preben

    2018-01-01

    inflammation is a potential modulator of endocrine function. The aim of this study was to investigate the effects of pulmonary exposure to carbonaceous nanomaterials on sperm quality parameters in an experimental mouse model.Methods: Effects on sperm quality after pulmonary inflammation induced by carbonaceous....... Pulmonary inflammation was determined by differential cell count in bronchoalveolar lavage fluid. Epididymal sperm concentration and motility were measured by computer-assisted sperm analysis. Epididymal sperm viability and morphological abnormalities were assessed manually using Hoechst 33,342/PI...... flourescent and Spermac staining, respectively. Epididymal sperm were assessed with regard to sperm DNA integrity (damage). Daily sperm production was measured in the testis, and testosterone levels were measured in blood plasma by ELISA.Results: Neutrophil numbers in the bronchoalveolar fluid showed...

  13. Immobilization of pentachlorophenol in soil using carbonaceous material amendments

    Energy Technology Data Exchange (ETDEWEB)

    Wen Bei [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, Haidian District, Beijing 100085 (China)], E-mail: bwen@rcees.ac.cn; Li Ruijuan; Zhang Shuzhen [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, Haidian District, Beijing 100085 (China); Shan Xiaoquan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, Haidian District, Beijing 100085 (China)], E-mail: xiaoquan@rcees.ac.cn; Fang Jing; Xiao Ke [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road, Haidian District, Beijing 100085 (China); Khan, Shahamat U. [Department of Chemistry and Biochemistry, MSN 3E2, George Mason University, 4400 University Drive, Fairfax, VA 22030-4444 (United States)

    2009-03-15

    In this study, three pentachlorophenol (PCP) laboratory-spiked and one field-contaminated soil were amended with 2.0% char, humic acid (HA) and peat, respectively. The amended soils were aged for either 7 or 250 days. After amendment, CaCl{sub 2} extractability of PCP was significantly decreased. Desorption kinetics indicated that the proposed amendment could lead to a strong binding and slow desorption of PCP in soils. Amendment with char reduced the bioaccumulation factor (BAF) of PCP most significantly for earthworms (Eisenia fetida) in all soils studied. The results of both physicochemical and biological tests suggested that amendment reduced PCP bioavailability quickly and enduringly, implying that carbonaceous material amendment, especially char amendment, was a potentially attractive in situ remediation method for sequestration of PCP in contaminated soil. - Carbonaceous material amendment was a potential in situ remediation method for pentachlorophenol contaminated soil.

  14. Study of chemical and physical properties of synthetic carbonaceous materials

    Energy Technology Data Exchange (ETDEWEB)

    Kaloc, M.; Lesko, J.; Martineg, P.; Rojak, A.; Roubicek, V.; Weiss, Z.

    1980-01-01

    Results are presented of studying the chemical and physical properties of 17 samples of synthetic carbonaceous materials (''carbons'') of different origin and with different degree of thermal treatment, and for comparison two samples of natural graphite were tested. For all the samples an analysis was made of the element composition and they were studied by the methods DTA, TGA, IR-spectrometry, x-ray analysis and electron screen microscopy. The studies indicated that proper combination of these methods can provide a high quality evaluation of the initial materials and the processes of their processing, and also the attained carbonaceous materials from the viewpoint of using them in the modern sectors of technology: electrical metallurgy, electrical chemistry and electrothermal production, nuclear technology, production of semiconductor materials, etc.

  15. 2004 EW95: A Phyllosilicate-bearing Carbonaceous Asteroid in the Kuiper Belt

    Science.gov (United States)

    Seccull, Tom; Fraser, Wesley C.; Puzia, Thomas H.; Brown, Michael E.; Schönebeck, Frederik

    2018-03-01

    Models of the Solar System’s dynamical evolution predict the dispersal of primitive planetesimals from their formative regions among the gas-giant planets due to the early phases of planetary migration. Consequently, carbonaceous objects were scattered both into the outer asteroid belt and out to the Kuiper Belt. These models predict that the Kuiper Belt should contain a small fraction of objects with carbonaceous surfaces, though to date, all reported visible reflectance spectra of small Kuiper Belt Objects (KBOs) are linear and featureless. We report the unusual reflectance spectrum of a small KBO, (120216) 2004 EW95, exhibiting a large drop in its near-UV reflectance and a broad shallow optical absorption feature centered at ∼700 nm, which is detected at greater than 4σ significance. These features, confirmed through multiple epochs of spectral photometry and spectroscopy, have respectively been associated with ferric oxides and phyllosilicates. The spectrum bears striking resemblance to those of some C-type asteroids, suggesting that 2004 EW95 may share a common origin with those objects. 2004 EW95 orbits the Sun in a stable mean motion resonance with Neptune, at relatively high eccentricity and inclination, suggesting it may have been emplaced there by some past dynamical instability. These results appear consistent with the aforementioned model predictions and are the first to show a reliably confirmed detection of silicate material on a small KBO.

  16. Morphology, composition and mixing state of individual carbonaceous aerosol in urban Shanghai

    Science.gov (United States)

    Fu, H.; Zhang, M.; Li, W.; Chen, J.; Wang, L.; Quan, X.; Wang, W.

    2012-01-01

    A total of 834 individual aerosol particles were collected during October and November 2010 in urban Shanghai, China. Particles were sampled under different weather and air quality conditions. Morphologies, compositions and mixing states of carbonaceous aerosols were investigated by transmission electron microscopy (TEM) coupled with energy-dispersive X-ray (EDX). Structures of some particles were verified using selected-area electron diffraction (SAED). Among the aerosol particles observed, carbonaceous aerosols were mainly categorized into four types: polymeric organic compound (POC), soot, tar ball, and biogenic particle. Based on the detailed TEM-EDX analysis, most of the particles were coated with secondary organic aerosols (SOA), which commonly formed through condensation or heterogeneous reactions of precursor gases on pre-existing particles. Aged particles were associated with days with low wind velocities, showed complex structures, and were bigger in size. The internally mixed particles of sulphates, organics and soot were encountered frequently. Such internally mixed particles may be preferentially formed during a stagnated air mass during serious pollution events, such as on 13 November. Although relative number counts varied with different species, sulphates (38-71%) and soot (11-22%) constituted the most dominant species observed in the samples. However, soil-derived particles (68%) were relatively more frequently observed on the sample collected on 12 November during a dust storm.

  17. Processes for liquefying carbonaceous feedstocks and related compositions

    Energy Technology Data Exchange (ETDEWEB)

    MacDonnell, Frederick M.; Dennis, Brian H.; Billo, Richard E.; Priest, John W.

    2017-02-28

    Methods for the conversion of lignites, subbituminous coals and other carbonaceous feedstocks into synthetic oils, including oils with properties similar to light weight sweet crude oil using a solvent derived from hydrogenating oil produced by pyrolyzing lignite are set forth herein. Such methods may be conducted, for example, under mild operating conditions with a low cost stoichiometric co-reagent and/or a disposable conversion agent.

  18. Organic matter in carbonaceous meteorites: past, present and future research.

    Science.gov (United States)

    Sephton, Mark A

    2005-12-15

    Carbonaceous meteorites are fragments of ancient asteroids that have remained relatively unprocessed since the formation of the Solar System. These carbon-rich objects provide a record of prebiotic chemical evolution and a window on the early Solar System. Many compound classes are present reflecting a rich organic chemical environment during the formation of the planets. Recent theories suggest that similar extraterrestrial organic mixtures may have acted as the starting materials for life on Earth.

  19. Indigenous Carbonaceous Matter in the Nakhla Mars Meteorite

    Science.gov (United States)

    Clemett, S. J.; Thomas-Keprta, K. L.; Rahman, Z.; Le, L.; Wentworth, S. J.; Gibson, E. K.; McKay, D. S.

    2016-01-01

    Detailed microanalysis of the Martian meteorite Nakhla has shown there are morphologically distinct carbonaceous features spatially associated with low-T aqueous alteration phases including salts and id-dingsite. A comprehensive suite of analytical instrumentation including optical microscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, focused ion beam (FIB) microscopy, transmission electron microscopy (TEM), two-step laser mass spectrometry (mu-L(sup 2)MS), laser mu-Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and nanoscale secondary ion mass spectrometry (NanoSIMS) are being used to characterize the carbonaceous matter and host mineralogy. The search for carbonaceous matter on Mars has proved challenging. Viking Landers failed to unambiguously detect simple organics at either of the two landing sites although the Martian surface is estimated to have acquired at least 10(exp15) kg of C as a consequence of meteoritic accretion over the last several Ga. The dearth of organics at the Martian surface has been attributed to various oxidative processes including UV photolysis and peroxide activity. Consequently, investigations of Martian organics need to be focused on the sub-surface regolith where such surface processes are either severely attenuated or absent. Fortuitously since Martian meteorites are derived from buried regolith materials they provide a unique opportunity to study Martian organic geochemistry.

  20. Carbonaceous Aerosol Characterization during 2016 KOR-US 2016

    Science.gov (United States)

    Rodriguez, B.; Santos, G. M.; Sanchez, D.; Jeong, D.; Czimczik, C. I.; Kim, S.

    2017-12-01

    Atmospheric carbonaceous aerosols are a major component of fine particulate matter and assume important roles in Earth's climate and human health. Because atmospheric carbonaceous aerosols exist as a continuum ranging from small, light-scattering organic carbon (OC), to highly-condensed, light-absorbing elemental carbon (EC) they have contrasting effects on interaction with incoming and outgoing radiation, cloud formation, and snow/ice albedo. By strengthening our understanding of the relative contribution and sources of OC and EC we will be able to further describe aerosol formation and mixing at the regional level. To understand the relative anthropogenic and biogenic contributions to carbonaceous aerosol, 12 PM10 aerosols samples were collected on quartz fiber filters at the Mt. Taewha Research Forest in South Korea during the KORUS-AQ 2016 campaign over periods of 24-48 hours with a high-volume air sampler. Analysis of bulk C and N concentrations and absorption properties of filter extracts interspersed with HYSPLIT model results indicated that continental outflow across the Yellow Sea in enriched in bulk nitrogen loading and enhanced bulk absorptive properties of the aerosols. Bulk radiocarbon analysis also indicated enriched values in all samples indicating contamination from a nuclear power plant or the combustion of biomedical waste nearby. Here, we aim to investigate further the chemical characterization of VOCs adsorbed unto the aerosol through TD-GC-TOFMS. With this dataset we aim to determine the relative contribution of anthropogenic and biogenic aerosols by utilizing specific chemical tracers for source apportionment.

  1. Pulsed-Laser Irradiation Space Weathering Of A Carbonaceous Chondrite

    Science.gov (United States)

    Thompson, M. S.; Keller, L. P.; Christoffersen, R.; Loeffler, M. J.; Morris, R. V.; Graff, T. G.; Rahman, Z.

    2017-01-01

    Grains on the surfaces of airless bodies experience irradiation from solar energetic particles and melting, vaporization and recondensation processes associated with micrometeorite impacts. Collectively, these processes are known as space weathering and they affect the spectral properties, composition, and microstructure of material on the surfaces of airless bodies, e.g. Recent efforts have focused on space weathering of carbonaceous materials which will be critical for interpreting results from the OSIRIS-REx and Hayabusa2 missions targeting primitive, organic-rich asteroids. In addition to returned sample analyses, space weathering processes are quantified through laboratory experiments. For example, the short-duration thermal pulse from hypervelocity micrometeorite impacts have been simulated using pulsed-laser irradiation of target material e.g. Recent work however, has shown that pulsed-laser irradiation has variable effects on the spectral properties and microstructure of carbonaceous chondrite samples. Here we investigate the spectral characteristics of pulsed-laser irradiated CM2 carbonaceous chondrite, Murchison, including the vaporized component. We also report the chemical and structural characteristics of specific mineral phases within the meteorite as a result of pulsed-laser irradiation.

  2. Microporous carbonaceous adsorbents for CO2 separation via selective adsorption

    KAUST Repository

    Zhao, Yunfeng

    2015-01-01

    Selective adsorption of CO2 has important implications for many energy and environment-related processes, which require the separation of CO2 from other gases (e.g. N2 and CH4) with high uptakes and selectivity. The development of high-performance adsorbents is one of the most promising solutions to the success of these processes. The present review is focused on the state-of-the-art of carbon-based (carbonaceous) adsorbents, covering microporous inorganic carbons and microporous organic polymers, with emphasis on the correlation between their textural and compositional properties and their CO2 adsorption/separation performance. Special attention is given to the most recently developed materials that were not covered in previous reviews. We summarize various effective strategies (N-doping, surface functionalization, extra-framework ions, molecular design, and pore size engineering) for enhancing the CO2 adsorption capacity and selectivity of carbonaceous adsorbents. Our discussion focuses on CO2/N2 separation and CO2/CH4 separation, while including an introduction to the methods and criteria used for evaluating the performance of the adsorbents. Critical issues and challenges regarding the development of high-performance adsorbents as well as some overlooked facts and misconceptions are also discussed, with the aim of providing important insights into the design of novel carbonaceous porous materials for various selective adsorption based applications. This journal is © The Royal Society of Chemistry.

  3. The color of carbonaceous aerosols in the ambient atmosphere

    Science.gov (United States)

    Liu, C.; Chung, C.; Zhang, F.; Yin, Y.; Zhao, D.

    2016-12-01

    Biomass burning aerosols, i.e. carbonaceous aerosols, mainly consist of black carbon (BC) and organic aerosols (OAs). Most OAs are non-absorptive, whereas some, e.g. brown carbon (BrC), can also significantly absorb solar radiation. However, the BC and BrC show quite different spectral habits on the absorption, and, thus, different colors. This presentation reveals the colors of carbonaceous aerosols in the ambient atmosphere. A combination of the particle scattering simulations, radiative transfer and RGB color model is used to display the color of an aerosol layer in the atmosphere, and BrC, BC and their mixture with scattering OAs are considered. Numerical results indicate that the color of the aerosol layer is substantially influenced by their absorption Ångström Exponent (AAE), not the species. Both the BCs and tar balls (TBs, a class of BrC) appear brownish at small particle sizes and becomes blackish at large sizes. At realistic size distributions, BCs look more blackish than TBs, but still exhibit some brown color. Meanwhile, if the aerosol layer absorbs over approximately 80% of the incident light (at green), all biomass burning aerosols become black in the atmosphere. The colors for mixture of purely scattering and absorptive carbonaceous aerosol layers in the atmosphere are also investigated. This study suggests that the brownishness of biomass burning aerosols indicates the amount of BC/BrC as well as the ratio of BC to BrC.

  4. Carbonaceous content of atmospheric aerosols in Lisbon urban atmosphere

    Science.gov (United States)

    Mirante, Fátima; Oliveira, C.; Martins, N.; Pio, C.; Caseiro, A.; Cerqueira, M.; Alves, C.; Oliveira, C.; Oliveira, J.; Camões, F.; Matos, M.; Silva, H.

    2010-05-01

    Lisbon is the capital city of Portugal with about 565,000 residents and a population density of 6,600 inhabitants per square kilometre. The town is surrounded by satellite cities, forming together a region known as "Lisbon Metropolitan Area" with about 3 million inhabitants. It is estimated that more than one million citizens come into the Lisbon area every day from the outskirts, leading to elevated traffic densities and intense traffic jams. Airborne particulate matter limit values are frequently exceeded, with important consequences on air pollution levels and obvious negative impacts on human health. Atmospheric aerosols are known to have in their structure significant amounts of carbonaceous material. The knowledge of the aerosols carbon content, particularly on their several carbon forms (as TC, EC and OC, meaning respectively Total, Elemental and Organic carbon) is often required to provide information for source attribution. In order to assess the vehicles PM input, two sampling campaigns (summer and winter periods) were carried out in 2008 in Lisbon in two contrasting sites, a roadside and an urban background site. Particulate matter was collected in two fractions on quartz fibre filters using Hi-Vol samplers (coarse fraction, 2.5µmfine fraction, Dpdust was also collected in each sampling site. Samples were analysed for elemental carbon (EC) and organic carbon (OC) concentrations by a thermal-optical method. The urban site presented the highest aerosol PM concentrations for the two size ranges, with PM10 average values of about 48 µg.m-3 and 27 µg.m-3 respectively for the roadside and urban background sites in the summer period, and about 44 µg.m-3 and 27 µg.m-3 in the winter season. In general, the concentrations of TC were higher at the roadside site, reflecting the input of EC from traffic. The OC presented a lower gradient, presumably due to the substantial secondary organic component. Both EC and OC showed higher concentrations in summer than in

  5. The Hemiptera type-material housed in the "Museu de Ciências Naturais, Fundação Zoobotânica do Rio Grande do Sul" of Porto Alegre, Brazil.

    Science.gov (United States)

    Ruschel, Tatiana Petersen; Guidoti, Marcus; Barcellos, Aline

    2013-01-01

    We provide a commented and referenced list on the type material deposited in the "Museu de Ciencias Naturais, Fundação Zoobotânica do Rio Grande do Sul", Porto Alegre, Brazil. Geographic coordinates are available on a digital repository for free access. High-resolution images of the specimens are available under request.

  6. Carbon Paste Electrodes Made from Different Carbonaceous Materials: Application in the Study of Antioxidants

    Science.gov (United States)

    Apetrei, Constantin; Apetrei, Irina Mirela; De Saja, Jose Antonio; Rodriguez-Mendez, Maria Luz

    2011-01-01

    This work describes the sensing properties of carbon paste electrodes (CPEs) prepared from three different types of carbonaceous materials: graphite, carbon microspheres and carbon nanotubes. The electrochemical responses towards antioxidants including vanillic acid, catechol, gallic acid, l-ascorbic acid and l-glutathione have been analyzed and compared. It has been demonstrated that the electrodes based on carbon microspheres show the best performances in terms of kinetics and stability, whereas G-CPEs presented the smallest detection limit for all the antioxidants analyzed. An array of electrodes has been constructed using the three types of electrodes. As demonstrated by means of Principal Component Analysis, the system is able to discriminate among antioxidants as a function of their chemical structure and reactivity. PMID:22319354

  7. In situ observation of D-rich carbonaceous globules embedded in NWA 801 CR2 chondrite

    Science.gov (United States)

    Hashiguchi, Minako; Kobayashi, Sachio; Yurimoto, Hisayoshi

    2013-12-01

    Eighty-five D-rich carbonaceous particles were identified in the matrix of the NWA 801 CR2 chondrite using isotope microscopy. The occurrence of 67 D-rich carbonaceous particles was characterized using secondary electron microscopy combined with X-ray elemental mapping. The close association of H and C, and D-enrichment suggests that the D-rich carbonaceous particles correspond to organic matter. The D-rich organic particles were scattered ubiquitously throughout the matrix at a concentration of approximately 660 ppm. The morphology of the D-rich carbonaceous particles is globular up to about 1 μm in diameter and is classified into four types: ring globules, round globules, irregular-shaped globules, and globule aggregates. The ring globules are ring-shaped organic matter containing silicate and/or oxide, with or without a void in the center. This is the first report of silicate and oxide grains surrounded by D-rich organic matter. The globule aggregates are composed of several D-rich organic globules mixed with silicates. Morphology of ring globules is very similar to core-mantle grain produced in the molecular cloud or in the outer solar nebula inferring by astronomy, suggesting that the organic globules have formed by UV photolysis in the ice mantle. Silicates or oxides attached to D-rich organic globules are the first observation among chondrites so far and may be unique nature of CR2 chondrites. The hydrogen isotopic compositions of the ring globules, round globules, irregular-shaped globules, and globule aggregates are δD = 3000-4800, 2900-8100, 2700-11,000, and 2500-11,000‰, respectively. Variations of D/H ratio of these organic globules seemed to be attributed to variations of D/H ratio of the organic radicals or differences of content of the D-rich organic radicals. There are no significant differences in the hydrogen isotopic compositions among the four types of D-rich carbonaceous matter. The D-enrichments suggest that these organic globules have

  8. Acid functionalized, highly dispersed carbonaceous spheres: an effective solid acid for hydrolysis of polysaccharides

    International Nuclear Information System (INIS)

    Jiang Yijun; Li Xiutao; Cao Quan; Mu Xindong

    2011-01-01

    Highly dispersed carbonaceous spheres with sulfonic acid groups were successfully prepared from glucose by hydrothermal method. Transmission electron microscopy (TEM) showed the as-synthesized carbonaceous materials were uniform, spherical in shape with an average diameter of about 450 nm. Fourier transform infrared (FT-IR) proved that –SO 3 H, –COOH, OH groups were grafted on the surface of the carbonaceous spheres during the sulfonation. Interestingly, the functionalized carbonaceous spheres exhibited high dispersibility in the polar solvent due to the hydrophilic groups on the surface. The mechanism of the formation for the carbonaceous spheres was also discussed based on the analysis of structure and composition. At last, the functionalized carbonaceous spheres were employed as solid acid to hydrolyze starch and cellulose. By comparison, the as-synthesized catalyst showed considerable high yield of glucose.

  9. Acid functionalized, highly dispersed carbonaceous spheres: an effective solid acid for hydrolysis of polysaccharides

    Science.gov (United States)

    Jiang, Yijun; Li, Xiutao; Cao, Quan; Mu, Xindong

    2011-02-01

    Highly dispersed carbonaceous spheres with sulfonic acid groups were successfully prepared from glucose by hydrothermal method. Transmission electron microscopy (TEM) showed the as-synthesized carbonaceous materials were uniform, spherical in shape with an average diameter of about 450 nm. Fourier transform infrared (FT-IR) proved that -SO3H, -COOH, OH groups were grafted on the surface of the carbonaceous spheres during the sulfonation. Interestingly, the functionalized carbonaceous spheres exhibited high dispersibility in the polar solvent due to the hydrophilic groups on the surface. The mechanism of the formation for the carbonaceous spheres was also discussed based on the analysis of structure and composition. At last, the functionalized carbonaceous spheres were employed as solid acid to hydrolyze starch and cellulose. By comparison, the as-synthesized catalyst showed considerable high yield of glucose.

  10. Characteristics and sources of carbonaceous aerosols from Shanghai, China

    Directory of Open Access Journals (Sweden)

    J.-J. Cao

    2013-01-01

    Full Text Available An intensive investigation of carbonaceous PM2.5 and TSP (total suspended particles from Pudong (China was conducted as part of the MIRAGE-Shanghai (Megacities Impact on Regional and Global Environment experiment in 2009. Data for organic and elemental carbon (OC and EC, organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs, and stable carbon isotopes OC (δ13COC and EC (δ13CEC were used to evaluate the aerosols' temporal variations and identify presumptive sources. High OC/EC ratios indicated a large fraction of secondary organic aerosol (SOA; high char/soot ratios indicated stronger contributions to EC from motor vehicles and coal combustion than biomass burning. Diagnostic ratios of PAHs indicated that much of the SOA was produced via coal combustion. Isotope abundances (δ13COC = −24.5 ± 0.8‰ and δ13CEC = −25.1 ± 0.6‰ indicated that fossil fuels were the most important source for carbonaceous PM2.5 (particulate matter less than 2.5 micrometers in diameter, with lesser impacts from biomass burning and natural sources. An EC tracer system and isotope mass balance calculations showed that the relative contributions to total carbon from coal combustion, motor vehicle exhaust, and SOA were 41%, 21%, and 31%; other primary sources such as marine, soil and biogenic emissions contributed 7%. Combined analyses of OC and EC, n-alkanes and PAHs, and stable carbon isotopes provide a new way to apportion the sources of carbonaceous particles.

  11. Source apportionment of carbonaceous aerosol in southern Sweden

    Directory of Open Access Journals (Sweden)

    J. Genberg

    2011-11-01

    Full Text Available A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM10 were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (14C and levoglucosan were measured. This approach enabled source apportionment of the total carbon in the PM10 fraction using the concentration ratios of the sources. The sources considered in this study were emissions from the combustion of fossil fuels and biomass, as well as biogenic sources. During the summer, the carbonaceous aerosol mass was dominated by compounds of biogenic origin (80%, which are associated with biogenic primary and secondary organic aerosols. During the winter months, biomass combustion (32% and fossil fuel combustion (28% were the main contributors to the carbonaceous aerosol. Elemental carbon concentrations in winter were about twice as large as during summer, and can be attributed to biomass combustion, probably from domestic wood burning. The contribution of fossil fuels to elemental carbon was stable throughout the year, although the fossil contribution to organic carbon increased during the winter. Thus, the organic aerosol originated mainly from natural sources during the summer and from anthropogenic sources during the winter. The result of this source apportionment was compared with results from the EMEP MSC-W chemical transport model. The model and measurements were generally consistent for total atmospheric organic carbon, however, the contribution of the sources varied substantially. E.g. the biomass burning contributions of OC were underestimated by the model by a factor of 2.2 compared to the measurements.

  12. Morphology and mixing state of individual freshly emitted wildfire carbonaceous particles.

    Science.gov (United States)

    China, Swarup; Mazzoleni, Claudio; Gorkowski, Kyle; Aiken, Allison C; Dubey, Manvendra K

    2013-01-01

    Biomass burning is one of the largest sources of carbonaceous aerosols in the atmosphere, significantly affecting earth's radiation budget and climate. Tar balls, abundant in biomass burning smoke, absorb sunlight and have highly variable optical properties, typically not accounted for in climate models. Here we analyse single biomass burning particles from the Las Conchas fire (New Mexico, 2011) using electron microscopy. We show that the relative abundance of tar balls (80%) is 10 times greater than soot particles (8%). We also report two distinct types of tar balls; one less oxidized than the other. Furthermore, the mixing of soot particles with other material affects their optical, chemical and physical properties. We quantify the morphology of soot particles and classify them into four categories: ~50% are embedded (heavily coated), ~34% are partly coated, ~12% have inclusions and~4% are bare. Inclusion of these observations should improve climate model performances.

  13. Photoelectric work function studies of carbonaceous films containing Ni nanocrystals

    International Nuclear Information System (INIS)

    Czerwosz, E.; Dluzewski, P.; Kutner, T.; Stacewicz, T.

    2003-01-01

    In this paper we present the results of photoelectric work function measurements for carbonaceous films containing Ni nanocrystals. The investigated films were obtained by thermal vacuum deposition method. The structure of films was studied by electron diffraction, transmission microscopy and Raman spectroscopy. Film structure depends on Ni contents in the film volume. Work function determined from photoelectric measurements for all investigated films are similar and lie in the range of 2.65-2.93 eV. The decrease of work function value with the cleaning of the film's surface with UV pulsed laser beam was observed

  14. Porous carbonaceous electrode structure and method for secondary electrochemical cell

    Science.gov (United States)

    Kaun, Thomas D.

    1977-03-08

    Positive and negative electrodes are provided as rigid, porous carbonaceous matrices with particulate active material fixedly embedded. Active material such as metal chalcogenides, solid alloys of alkali metal or alkaline earth metals along with other metals and their oxides in particulate form are blended with a thermosetting resin and a solid volatile to form a paste mixture. Various electrically conductive powders or current collector structures can be blended or embedded into the paste mixture which can be molded to the desired electrode shape. The molded paste is heated to a temperature at which the volatile transforms into vapor to impart porosity as the resin begins to cure into a rigid solid structure.

  15. Sub-micrometer refractory carbonaceous particles in the polar stratosphere

    Science.gov (United States)

    Schütze, Katharina; Wilson, James Charles; Weinbruch, Stephan; Benker, Nathalie; Ebert, Martin; Günther, Gebhard; Weigel, Ralf; Borrmann, Stephan

    2017-10-01

    Eleven particle samples collected in the polar stratosphere during SOLVE (SAGE III Ozone loss and validation experiment) from January until March 2000 were characterized in detail by high-resolution transmission and scanning electron microscopy (TEM/SEM) combined with energy-dispersive X-ray microanalysis. A total of 4202 particles (TEM = 3872; SEM = 330) were analyzed from these samples, which were collected mostly inside the polar vortex in the altitude range between 17.3 and 19.9 km. Particles that were volatile in the microscope beams contained ammonium sulfates and hydrogen sulfates and dominated the samples. Some particles with diameters ranging from 20 to 830 nm were refractory in the electron beams. Carbonaceous particles containing additional elements to C and O comprised from 72 to 100 % of the refractory particles. The rest were internal mixtures of these materials with sulfates. The median number mixing ratio of the refractory particles, expressed in units of particles per milligram of air, was 1.1 (mg air)-1 and varied between 0.65 and 2.3 (mg air)-1. Most of the refractory carbonaceous particles are completely amorphous, a few of the particles are partly ordered with a graphene sheet separation distance of 0.37 ± 0.06 nm (mean value ± standard deviation). Carbon and oxygen are the only detected major elements with an atomic O/C ratio of 0.11 ± 0.07. Minor elements observed include Si, S, Fe, Cr and Ni with the following atomic ratios relative to C: Si/C: 0.010 ± 0.011; S/C: 0.0007 ± 0.0015; Fe/C: 0.0052 ± 0.0074; Cr/C: 0.0012 ± 0.0017; Ni/C: 0.0006 ± 0.0011 (all mean values ± standard deviation).High-resolution element distribution images reveal that the minor elements are distributed within the carbonaceous matrix; i.e., heterogeneous inclusions are not observed. No difference in size, nanostructure and elemental composition was found between particles collected inside and outside the polar vortex. Based on chemistry and nanostructure

  16. Water and the thermal evolution of carbonaceous chondrite parent bodies

    Science.gov (United States)

    Grimm, Robert E.; Mcsween, Harry Y., Jr.

    1989-01-01

    Two hypotheses are proposed for the aqueous alteration of carbonaceous chondrites within their parent bodies, in which respectively the alteration occurs (1) throughout the parent body interior, or (2) in a postaccretional surface regolith; both models assume an initially homogeneous mixture of ice and rock that is heated through the decay of Al-26. Water is seen to exert a powerful influence on chondrite evolution through its role of thermal buffer, permitting substitution of a low temperature aqueous alteration for high temperature recrystallization. It is quantitatively demonstrated that liquid water may be introduced by either hydrothermal circulation, vapor diffusion from below, or venting due to fracture.

  17. Liquefaction of solid carbonaceous material with catalyst recycle

    Science.gov (United States)

    Gupta, Avinash; Greene, Marvin I.

    1992-01-01

    In the two stage liquefaction of a carbonaceous solid such as coal wherein coal is liquefied in a first stage in the presence of a liquefaction solvent and the first stage effluent is hydrogenated in the presence of a supported hydrogenation catalyst in a second stage, catalyst which has been previously employed in the second stage and comminuted to a particle size distribution equivalent to 100% passing through U.S. 100 Mesh, is passed to the first stage to improve the overall operation.

  18. Carbon-14 Content of Carbonaceous Deposits in Oldbury Core Graphite

    International Nuclear Information System (INIS)

    Metcalfe, M.P.; Tzelepi, A.; Gill, J.

    2016-01-01

    Graphite specimens taken from the surface of Magnox reactor core components have been studied by differential thermal oxidation and counting of off-gases to quantify the contribution or otherwise of carbonaceous deposits to the C-14 inventory of the core graphite. While present within the open porosity of the graphite, such deposits formed from polymerization reactions in the CO 2 /CO atmosphere of the reactor and from the decomposition of methane are concentrated predominantly on the outer surfaces of components. An improved understanding of their C-14 content could influence handling of material during decommissioning and could influence treatment options. (author)

  19. Low-temperature catalytic conversion of carbonaceous materials

    Directory of Open Access Journals (Sweden)

    Tabakaev Roman B.

    2015-01-01

    Full Text Available Laws of the rate of carbon conversion in steam atmosphere at a temperature in modes of the catalytic low-temperature treatment of peat, brown coal, semi-coke from peat and brown coal are obtained by experiments. Increasing of the rate of carbon conversion in temperature range up to 500 °C is achieved by using of catalysts. The possibility of using results is associated with the burners, a working zone of which is porous filling from carbonaceous particles.

  20. Laboratory Experiments and Instrument Intercomparison Studies of Carbonaceous Aerosol Particles

    Energy Technology Data Exchange (ETDEWEB)

    Davidovits, Paul [Boston College, Chestnut Hill, MA (United States)

    2015-10-20

    Aerosols containing black carbon (and some specific types of organic particulate matter) directly absorb incoming light, heating the atmosphere. In addition, all aerosol particles backscatter solar light, leading to a net-cooling effect. Indirect effects involve hydrophilic aerosols, which serve as cloud condensation nuclei (CCN) that affect cloud cover and cloud stability, impacting both atmospheric radiation balance and precipitation patterns. At night, all clouds produce local warming, but overall clouds exert a net-cooling effect on the Earth. The effect of aerosol radiative forcing on climate may be as large as that of the greenhouse gases, but predominantly opposite in sign and much more uncertain. The uncertainties in the representation of aerosol interactions in climate models makes it problematic to use model projections to guide energy policy. The objective of our program is to reduce the uncertainties in the aerosol radiative forcing in the two areas highlighted in the ASR Science and Program Plan. That is, (1) addressing the direct effect by correlating particle chemistry and morphology with particle optical properties (i.e. absorption, scattering, extinction), and (2) addressing the indirect effect by correlating particle hygroscopicity and CCN activity with particle size, chemistry, and morphology. In this connection we are systematically studying particle formation, oxidation, and the effects of particle coating. The work is specifically focused on carbonaceous particles where the uncertainties in the climate relevant properties are the highest. The ongoing work consists of laboratory experiments and related instrument inter-comparison studies both coordinated with field and modeling studies, with the aim of providing reliable data to represent aerosol processes in climate models. The work is performed in the aerosol laboratory at Boston College. At the center of our laboratory setup are two main sources for the production of aerosol particles: (a

  1. Light absorption of biomass burning and vehicle emission-sourced carbonaceous aerosols of the Tibetan Plateau.

    Science.gov (United States)

    Hu, Zhaofu; Kang, Shichang; Li, Chaoliu; Yan, Fangping; Chen, Pengfei; Gao, Shaopeng; Wang, Zhiyong; Zhang, Yulan; Sillanpää, Mika

    2017-06-01

    Carbonaceous aerosols over the Tibetan Plateau originate primarily from biomass burning and vehicle emissions (BB and VEs, respectively). The light absorption characteristics of these carbonaceous aerosols are closely correlated with the burning conditions and represent key factors that influence climate forcing. In this study, the light absorption characteristics of elemental carbon (EC) and water-soluble organic carbon (WSOC) in PM 2.5 (fine particulate matter smaller than 2.5 μm) generated from BB and VEs were investigated over the Tibetan Plateau (TP). The results showed that the organic carbon (OC)/EC ratios from BB- and VE-sourced PM 2.5 were 17.62 ± 10.19 and 1.19 ± 0.36, respectively. These values were higher than the ratios in other regions, which was primarily because of the diminished amount of oxygen over the TP. The mass absorption cross section of EC (MAC EC ) at 632 nm for the BB-sourced PM 2.5 (6.10 ± 1.21 m 2 .g -1 ) was lower than that of the VE-sourced PM 2.5 (8.10 ± 0.98 m 2 .g -1 ), indicating that the EC content of the BB-sourced PM 2.5 was overestimated because of the high OC/EC ratio. The respective absorption per mass (α/ρ) values at 365 nm for the VE- and BB-sourced PM 2.5 were 0.71 ± 0.17 m 2 .g -1 and 0.91 ± 0.18 m 2 .g -1 . The α/ρ value of the VEs was loaded between that of gasoline and diesel emissions, indicating that the VE-sourced PM 2.5 originated from both types of emissions. Because OC and WSOC accounts for most of the carbonaceous aerosols at remote area of the TP, the radiative forcing contributed by the WSOC should be high, and requires further investigation.

  2. Constraining Carbonaceous Aerosol Climate Forcing by Bridging Laboratory, Field and Modeling Studies

    Science.gov (United States)

    Dubey, M. K.; Aiken, A. C.; Liu, S.; Saleh, R.; Cappa, C. D.; Williams, L. R.; Donahue, N. M.; Gorkowski, K.; Ng, N. L.; Mazzoleni, C.; China, S.; Sharma, N.; Yokelson, R. J.; Allan, J. D.; Liu, D.

    2014-12-01

    Biomass and fossil fuel combustion emits black (BC) and brown carbon (BrC) aerosols that absorb sunlight to warm climate and organic carbon (OC) aerosols that scatter sunlight to cool climate. The net forcing depends strongly on the composition, mixing state and transformations of these carbonaceous aerosols. Complexities from large variability of fuel types, combustion conditions and aging processes have confounded their treatment in models. We analyse recent laboratory and field measurements to uncover fundamental mechanism that control the chemical, optical and microphysical properties of carbonaceous aerosols that are elaborated below: Wavelength dependence of absorption and the single scattering albedo (ω) of fresh biomass burning aerosols produced from many fuels during FLAME-4 was analysed to determine the factors that control the variability in ω. Results show that ω varies strongly with fire-integrated modified combustion efficiency (MCEFI)—higher MCEFI results in lower ω values and greater spectral dependence of ω (Liu et al GRL 2014). A parameterization of ω as a function of MCEFI for fresh BB aerosols is derived from the laboratory data and is evaluated by field data, including BBOP. Our laboratory studies also demonstrate that BrC production correlates with BC indicating that that they are produced by a common mechanism that is driven by MCEFI (Saleh et al NGeo 2014). We show that BrC absorption is concentrated in the extremely low volatility component that favours long-range transport. We observe substantial absorption enhancement for internally mixed BC from diesel and wood combustion near London during ClearFlo. While the absorption enhancement is due to BC particles coated by co-emitted OC in urban regions, it increases with photochemical age in rural areas and is simulated by core-shell models. We measure BrC absorption that is concentrated in the extremely low volatility components and attribute it to wood burning. Our results support

  3. Evaluation of traffic exhaust contributions to ambient carbonaceous submicron particulate matter in an urban roadside environment in Hong Kong

    Science.gov (United States)

    Lee, Berto Paul; Kwok Keung Louie, Peter; Luk, Connie; Keung Chan, Chak

    2017-12-01

    Road traffic has significant impacts on air quality particularly in densely urbanized and populated areas where vehicle emissions are a major local source of ambient particulate matter. Engine type (i.e., fuel use) significantly impacts the chemical characteristics of tailpipe emission, and thus the distribution of engine types in traffic impacts measured ambient concentrations. This study provides an estimation of the contribution of vehicles powered by different fuels (gasoline, diesel, LPG) to carbonaceous submicron aerosol mass (PM1) based on ambient aerosol mass spectrometer (AMS) and elemental carbon (EC) measurements and vehicle count data in an urban inner city environment in Hong Kong with the aim to gauge the importance of different engine types to particulate matter burdens in a typical urban street canyon. On an average per-vehicle basis, gasoline vehicles emitted 75 and 93 % more organics than diesel and LPG vehicles, respectively, while EC emissions from diesel vehicles were 45 % higher than those from gasoline vehicles. LPG vehicles showed no appreciable contributions to EC and thus overall represented a small contributor to traffic-related primary ambient PM1 despite their high abundance (˜ 30 %) in the traffic mix. Total carbonaceous particle mass contributions to ambient PM1 from diesel engines were only marginally higher (˜ 4 %) than those from gasoline engines, which is likely an effect of recently introduced control strategies targeted at commercial vehicles and buses. Overall, gasoline vehicles contributed 1.2 µg m-3 of EC and 1.1 µ m-3 of organics, LPG vehicles 0.6 µg m-3 of organics and diesel vehicles 2.0 µg m-3 of EC and 0.7 µg m-3 of organics to ambient carbonaceous PM1.

  4. Recent Development of Carbonaceous Materials for Lithium–Sulphur Batteries

    Directory of Open Access Journals (Sweden)

    Xingxing Gu

    2016-11-01

    Full Text Available The effects of climate change are just beginning to be felt, and as such, society must work towards strategies of reducing humanity’s impact on the environment. Due to the fact that energy production is one of the primary contributors to greenhouse gas emissions, it is obvious that more environmentally friendly sources of power are required. Technologies such as solar and wind power are constantly being improved through research; however, as these technologies are often sporadic in their power generation, efforts must be made to establish ways to store this sustainable energy when conditions for generation are not ideal. Battery storage is one possible supplement to these renewable energy technologies; however, as current Li-ion technology is reaching its theoretical capacity, new battery technology must be investigated. Lithium–sulphur (Li–S batteries are receiving much attention as a potential replacement for Li-ion batteries due to their superior capacity, and also their abundant and environmentally benign active materials. In the spirit of environmental harm minimization, efforts have been made to use sustainable carbonaceous materials for applications as carbon–sulphur (C–S composite cathodes, carbon interlayers, and carbon-modified separators. This work reports on the various applications of carbonaceous materials applied to Li–S batteries, and provides perspectives for the future development of Li–S batteries with the aim of preparing a high energy density, environmentally friendly, and sustainable sulphur-based cathode with long cycle life.

  5. Ethanol and other oxygenateds from low grade carbonaceous resources

    Energy Technology Data Exchange (ETDEWEB)

    Joo, O.S.; Jung, K.D.; Han, S.H. [Korea Institute of Science and Technology, Seoul (Korea, Democratic People`s Republic of)] [and others

    1995-12-31

    Anhydrous ethanol and other oxygenates of C2 up can be produced quite competitively from low grade carbonaceous resources in high yield via gasification, methanol synthesis, carbonylation of methanol an hydrogenation consecutively. Gas phase carbonylation of methanol to form methyl acetate is the key step for the whole process. Methyl acetate can be produced very selectively in one step gas phase reaction on a fixed bed column reactor with GHSV over 5,000. The consecutive hydrogenation of methyl or ethyl acetate produce anhydrous ethanol in high purity. It is also attempted to co-produce methanol and DME in IGCC, in which low grade carbonaceous resources are used as energy sources, and the surplus power and pre-power gas can be stored in liquid form of methanol and DME during base load time. Further integration of C2 up oxygenate production with IGCC can improve its economics. The attempt of above extensive technology integration can generate significant industrial profitability as well as reduce the environmental complication related with massive energy consumption.

  6. Review of the technology for solar gasification of carbonaceous materials

    International Nuclear Information System (INIS)

    Epstein, M.; Spiewak, I.; Funken, K.H.; Ortner, J.

    1994-01-01

    Research has demonstrated the feasibility of solar assisted gasification of carbonaceous materials to form synthesis gas (syngas). The potential feedstocks range from natural gas, residual oil, biomass, and oil-shale to coal. The expected advantages of such processing are yields of syngas with calorific values above those of the carbonaceous feedstocks, syngas quality suited to production of hydrogen, methanol or bulk Fischer-Tropsch fuels, and the ability to process low-grade and waste materials with essentially no emissions to atmosphere other than small amounts of CO 2 . The review provides some background on solar receiver concepts to reach the high temperatures needed for syngas production, the basic chemistry involved, covers applicable experiments that have been reported with solar inputs and with conventional heating, heat transfer processes, process and energy balances, and cost analysis. Approximately 80 references are cited. The authors present their views on the most promising approaches to solar-assisted gasification, the technology development required, and the ultimate benefits of such development and commercialization

  7. Heavy-ion irradiation induced diamond formation in carbonaceous materials

    International Nuclear Information System (INIS)

    Daulton, T. L.

    1999-01-01

    The basic mechanisms of metastable phase formation produced under highly non-equilibrium thermodynamic conditions within high-energy particle tracks are investigated. In particular, the possible formation of diamond by heavy-ion irradiation of graphite at ambient temperature is examined. This work was motivated, in part, by earlier studies which discovered nanometer-grain polycrystalline diamond aggregates of submicron-size in uranium-rich carbonaceous mineral assemblages of Precambrian age. It was proposed that the radioactive decay of uranium formed diamond in the fission particle tracks produced in the carbonaceous minerals. To test the hypothesis that nanodiamonds can form by ion irradiation, fine-grain polycrystalline graphite sheets were irradiated with 400 MeV Kr ions. The ion irradiated graphite (and unirradiated graphite control) were then subjected to acid dissolution treatments to remove the graphite and isolate any diamonds that were produced. The acid residues were then characterized by analytical and high-resolution transmission electron microscopy. The acid residues of the ion-irradiated graphite were found to contain ppm concentrations of nanodiamonds, suggesting that ion irradiation of bulk graphite at ambient temperature can produce diamond

  8. Regional variation of carbonaceous aerosols from space and simulations

    Science.gov (United States)

    Mukai, Sonoyo; Sano, Itaru; Nakata, Makiko; Kokhanovsky, Alexander

    2017-04-01

    Satellite remote sensing provides us with a systematic monitoring in a global scale. As such, aerosol observation via satellites is known to be useful and effective. However, before attempting to retrieve aerosol properties from satellite data, the efficient algorithms for aerosol retrieval need to be considered. The characteristics and distributions of atmospheric aerosols are known to be complicated, owing to both natural factors and human activities. It is known that the biomass burning aerosols generated by the large-scale forest fires and burn agriculture have influenced the severity of air pollution. Nevertheless the biomass burning episodes increase due to global warming and climate change and vice versa. It is worth noting that the near ultra violet (NUV) measurements are helpful for the detection of carbonaceous particles, which are the main component of aerosols from biomass burning. In this work, improved retrieval algorithms for biomass burning aerosols are shown by using the measurements observed by GLI and POLDER-2 on Japanese short term mission ADEOS-2 in 2003. The GLI sensor has 380nm channel. For detection of biomass burning episodes, the aerosol optical thickness of carbonaceous aerosols simulated with the numerical model simulations (SPRINTARS) is available as well as fire products from satellite imagery. Moreover the algorithm using shorter wavelength data is available for detection of absorbing aerosols. An algorithm based on the combined use of near-UV and violet data has been introduced in our previous work with ADEOS (Advanced Earth Observing Satellite) -2 /GLI measurements [1]. It is well known that biomass burning plume is a seasonal phenomenon peculiar to a particular region. Hence, the mass concentrations of aerosols are frequently governed with spatial and/or temporal variations of biomass burning plumes. Accordingly the satellite data sets for our present study are adopted from the view points of investigation of regional and seasonal

  9. Space weathering trends on carbonaceous asteroids: A possible explanation for Bennu's blue slope?

    Science.gov (United States)

    Lantz, C.; Binzel, R. P.; DeMeo, F. E.

    2018-03-01

    We compare primitive near-Earth asteroid spectral properties to the irradiated carbonaceous chondrite samples of Lantz et al. (2017) in order to assess how space weathering processes might influence taxonomic classification. Using the same eigenvectors from the asteroid taxonomy by DeMeo et al. (2009), we calculate the principal components for fresh and irradiated meteorites and find that change in spectral slope (blueing or reddening) causes a corresponding shift in the two first principal components along the same line that the C- and X-complexes track. Using a sample of B-, C-, X-, and D-type NEOs with visible and near-infrared spectral data, we further investigated the correlation between prinicipal components and the spectral curvature for the primitive asteroids. We find that space weathering effects are not just slope and albedo, but also include spectral curvature. We show how, through space weathering, surfaces having an original "C-type" reflectance can thus turn into a redder P-type or a bluer B-type, and that space weathering can also decrease (and disguise) the D-type population. Finally we take a look at the case of OSIRIS-REx target (101955) Bennu and propose an explanation for the blue and possibly red spectra that were previously observed on different locations of its surface: parts of Bennu's surface could have become blue due to space weathering, while fresher areas are redder. No clear prediction can be made on Hayabusa-2 target (162173) Ryugu.

  10. Influence of Bulk Carbonaceous Matter on Pluto's Structure and Evolution

    Science.gov (United States)

    McKinnon, W. B.; Stern, S. A.; Weaver, H. A., Jr.; Spencer, J. R.; Moore, J. M.; Young, L. A.; Olkin, C.

    2017-12-01

    The rock/ice mass ratio of the Pluto system is about 2/1 (McKinnon et al., Icarus 287, 2017) [1], though this neglects the potential role of bulk carbonaceous matter ("CHON"), an important cometary component and one likely important in the ancestral Kuiper belt. The wealth of measurements at comet 67P/Churyumov-Gerasimenko (a Jupiter-family comet and thus one formed in the same region of the outer Solar System as Pluto) by Rosetta are particularly instructive. E.g., Davidsson et al. (A&A 592, 2016) [2] propose in their "composition A" that 67P/Ch-G is 25% metal/sulfides, 42% rock/organics, and 32% ice by mass. For their assumed component densities, the overall grain density is 1820 kg/m3. Fulle et al. (MNRAS 462, 2016) [3] posit 5 ± 2 volume % Fe-sulfides of density 4600 kg/m3, 28 ± 5% Mg,Fe-olivines and -pyroxenes of density 3200 kg/m3, 52 ± 12% hydrocarbons of density 1200 kg/m3, and 15 ± 6% ices of 917 kg/m3. This composition yields a primordial grain density (dust + ice) of 1885 ± 240 kg/m3. Both of these cometary density estimates [2,3] are consistent with Pluto-Charon, especially as Pluto's uncompressed (STP) density is close to 1820 kg/m3 and that of the system as a whole is close to 1800 kg/m3 [1]. We consider the potential compositional and structural implications of these proposed 67P/Ch-G compositions when applied to Pluto and Charon. The amount of ice in model A of [2] is a good match to Pluto structural models. Their rock/organics component, however, is taken to be half graphite (2000 kg/m3) by volume. The composition in [3] is more divergent: very ice poor, and on the order of 50% light hydrocarbons by volume. Regardless of the differences between [2] and [3], the possibility of massive internal graphite or carbonaceous layers within Pluto is real. We discuss the possible consequences for Pluto's structure, rock/ice ratio, thermal and chemical evolution, and even interpretation of its gravity field from tectonics. For example, radiogenic heat

  11. Nudności i wymioty

    Directory of Open Access Journals (Sweden)

    Anna Mokrowiecka

    2010-12-01

    Full Text Available Nudności są nieprzyjemnym, niebolesnym odczuciem silnej, nieodpartej potrzeby zwymiotowania, z kolei wymioty polegają na gwałtownym wydaleniu treści żołądka przez usta w wyniku silnych skurczów mięśni brzucha i klatki piersiowej. Nudności i wymioty mogą występować niezależnie od siebie, ale najczęściej są ze sobą powiązane. Nudności i wymioty powstają w odpowiedzi zarówno na bodźce fizjologiczne, jak i patologiczne. Zwykle jednak przewlekłe nudności i wymioty są objawem chorób przewodu pokarmowego lub innych narządów. Choroby przewodu pokarmowego i otrzewnej stanowią szeroką grupę chorób wywołujących nudności i wymioty, począwszy od nieżytu żołądkowo-jelitowego o ostrym infekcyjnym tle, przez zatrucie pokarmowe i nadwrażliwość pokarmową, do stanów ostrych – niedrożności jelita cienkiego lub/i grubego. Leki i toksyny, między innymi cytostatyki, są jedną z najczęstszych przyczyn nudności i wymiotów. Wśród innych przyczyn nudności i wymiotów można wymienić: choroby OUN prowadzące do zwiększenia ciśnienia śródczaszkowego, choroby endokrynologiczne i metaboliczne (mocznica, kwasica ketonowa w cukrzycy, choroby tarczycy i przytarczyc oraz choroba Addisona, zawał ściany dolnej mięśnia sercowego, nudności i wymioty pooperacyjne. Nudności i wymioty jako choroby czynnościowe zostały ujęte w III kryteriach rzymskich w punkcie „Choroby czynnościowe żołądka i dwunastnicy”. W diagnostyce różnicowej należy uwzględnić czas trwania wymiotów, czas pomiędzy posiłkiem a wystąpieniem wymiotów, a także charakter treści wymiocin i inne objawy towarzyszące. Wywiad i badanie fizykalne dostarczają zwykle wystarczających informacji do postawienia prawidłowej diagnozy i ustalenia leczenia u większości chorych cierpiących na nudności i wymioty. Niektórzy pacjenci wymagają jednak badań laboratoryjnych, obrazowych i endoskopowych przed zastosowaniem odpowiedniej

  12. Enantiomeric and Isotopic Analysis of Organic Compounds in Carbonaceous Meteorites

    Science.gov (United States)

    Cooper, George

    2004-01-01

    Carbonaceous meteorites are relatively enriched in soluble organic compounds. The Murchison and Murray meteorites contain numerous compounds of interest in the study of early solar system organic chemistry and organic compounds of potential importance for the origin of life. These include: amino acids, amides, carboxylic acids, and polyols. This talk will focus on the enantiomeric and isotopic analysis of individual meteoritic compounds - primarily polyol acids. The analyses will determine if, in addition to certain amino acids from Murchison, another potentially important class of prebiotic compounds also contains enantiomeric excesses, i.e., excesses that could have contributed to the current homochirality of life. Preliminary enantiomeric and isotopic (C- 13) measurements of Murchison glyceric acid show that it is indeed extraterrestrial. C-13 and D isotope analysis of meteoritic sugar alcohols (glycerol, threitol, ribitol, etc.) has shown that they are also indigenous to the meteorite.

  13. Agglomeration processes in carbonaceous dusty plasmas, experiments and numerical simulations

    International Nuclear Information System (INIS)

    Dap, S; Hugon, R; De Poucques, L; Bougdira, J; Lacroix, D; Patisson, F

    2010-01-01

    This paper deals with carbon dust agglomeration in radio frequency acetylene/argon plasma. Two studies, an experimental and a numerical one, were carried out to model dust formation mechanisms. Firstly, in situ transmission spectroscopy of dust clouds in the visible range was performed in order to observe the main features of the agglomeration process of the produced carbonaceous dust. Secondly, numerical simulation tools dedicated to understanding the achieved experiments were developed. A first model was used for the discretization of the continuous population balance equations that characterize the dust agglomeration process. The second model is based on a Monte Carlo ray-tracing code coupled to a Mie theory calculation of dust absorption and scattering parameters. These two simulation tools were used together in order to numerically predict the light transmissivity through a dusty plasma and make comparisons with experiments.

  14. Sub-micrometer refractory carbonaceous particles in the polar stratosphere

    Directory of Open Access Journals (Sweden)

    K. Schütze

    2017-10-01

    Full Text Available Eleven particle samples collected in the polar stratosphere during SOLVE (SAGE III Ozone loss and validation experiment from January until March 2000 were characterized in detail by high-resolution transmission and scanning electron microscopy (TEM/SEM combined with energy-dispersive X-ray microanalysis. A total of 4202 particles (TEM  =  3872; SEM  =  330 were analyzed from these samples, which were collected mostly inside the polar vortex in the altitude range between 17.3 and 19.9 km. Particles that were volatile in the microscope beams contained ammonium sulfates and hydrogen sulfates and dominated the samples. Some particles with diameters ranging from 20 to 830 nm were refractory in the electron beams. Carbonaceous particles containing additional elements to C and O comprised from 72 to 100 % of the refractory particles. The rest were internal mixtures of these materials with sulfates. The median number mixing ratio of the refractory particles, expressed in units of particles per milligram of air, was 1.1 (mg air−1 and varied between 0.65 and 2.3 (mg air−1. Most of the refractory carbonaceous particles are completely amorphous, a few of the particles are partly ordered with a graphene sheet separation distance of 0.37 ± 0.06 nm (mean value ± standard deviation. Carbon and oxygen are the only detected major elements with an atomic O∕C ratio of 0.11 ± 0.07. Minor elements observed include Si, S, Fe, Cr and Ni with the following atomic ratios relative to C: Si∕C: 0.010 ± 0.011; S∕C: 0.0007 ± 0.0015; Fe∕C: 0.0052 ± 0.0074; Cr∕C: 0.0012 ± 0.0017; Ni∕C: 0.0006 ± 0.0011 (all mean values ± standard deviation.High-resolution element distribution images reveal that the minor elements are distributed within the carbonaceous matrix; i.e., heterogeneous inclusions are not observed. No difference in size, nanostructure and elemental composition was found between

  15. Optimum utilization of low ash carbonaceous constituents in stamp charging

    Energy Technology Data Exchange (ETDEWEB)

    Dash, P.S.; Krishnan, S.H.; Sharma, R. [Tata Steel, Jamshedpur (India)

    2004-07-01

    To produce high strength coke at reasonable cost, Tata Steel went for stamp charging along with 40-45% imported coal. It is imperative to design the base stamp charge coal blend so as to possess enough fluidity to assimilate these infusible inerts and still produce coke with high coke strength after reaction (CSR). This paper describes the scope of utilising low ash carbonaceous inerts like fluid coke (a petroleum coke made in a fluidized bed) and anthracite optimally in the stamp charging blend by replacing the present imported semi-soft coal with high fluidity imported coals. The laboratory scale experimentation and its results regarding improvement in coke properties and yield are also described. 5 refs., 2 figs., 3 tabs.

  16. On thermodynamics of methane+carbonaceous materials adsorption

    KAUST Repository

    Rahman, Kazi Afzalur

    2012-01-01

    This study presents the theoretical frameworks for the thermodynamic quantities namely the heat of adsorption, specific heat capacity, entropy, and enthalpy for the adsorption of methane onto various carbonaceous materials. The proposed theoretical frameworks are developed from the rigor of thermodynamic property surfaces of a single component adsorbate-adsorbent system and by incorporating the micropore filling theory approach, where the effect of adsorbed phase volume is considered. The abovementioned thermodynamic properties are quantitatively evaluated from the experimental uptake data for methane adsorption onto activated carbons such as Maxsorb III at temperatures ranging from 120 to 350 K and pressures up to 25 bar. Employing the proposed thermodynamic approaches, this paper shows the thermodynamic maps of the charge and discharge processes of adsorbed natural gas (ANG) storage system for understanding the behaviors of natural gas in ANG vessel. © 2011 Elsevier Ltd. All rights reserved.

  17. On the morphology and optics of carbonaceous aerosols

    Science.gov (United States)

    Chakrabarty, Rajan Kumar

    Understanding of the complex morphology and optical properties of combustion-generated carbonaceous aerosols has been a challenging research topic. Calculation of aerosol radiative forcing and satellite aerosol retrievals depends critically on the knowledge of aerosol optical properties, which are a function of particle morphology, size, and refractive index. In addition, aerosol morphology is an important control parameter in industrial aerosol generation and use. Ensembles of aerosols often include a variety of complex morphologies, but these morphologies currently cannot be separated and very little is known about their influence on other aerosol parameters. In this dissertation, a novel charge-based technique for classifying fractal-like aerosol agglomerates based on their morphology is demonstrated. Using this technique, the formation mechanism and optical properties of fractal-like carbonaceous aerosols from a high-temperature combustion system (premixed flame) are investigated. Contrary to previous observations of a universal mass fractal dimension of ≈1.8 for fractal-like aerosol aggregates formed in the dilute-limit of a premixed flame via 3-dimensional diffusion-limited cluster aggregation (DLCA) processes, minority populations (≈3%) of aggregates yielding low mass fractal dimensions between 1.2 and 1.51 were observed. Two hypotheses are presented to explain this observation. To improve our understanding of the validity of optical theories for fractal-like chain aggregates, real-time optical measurements of fractal-like aggregates were compared with the prediction by three optical theories, namely Rayleigh-Debye-Gans (RDG) approximation, volume-equivalent Mie theory, and integral equation formulation for scattering (IEFS). The RDG approximation agreed within 10% with the experimental results and the exact electromagnetic calculations of the IEFS theory, while volume-equivalent Mie theory overpredicted the experimental scattering coefficient by a

  18. Fundamental studies of chalcogenide nanocrystals, carbonaceous nanoparticles, and chromatographic materials

    Science.gov (United States)

    Baker, Jared Scott

    2011-12-01

    The development of novel nanomaterials and the understanding of their fundamental physical and chemical properties represent an exciting area of research. These materials are continuously being sought for ever-increasing applications; finding their way into uses that influence mankind on a daily basis. Combining elements from traditional nanoparticle characterization with electrophoretic-based techniques, this dissertation presents the analysis of carbon nanoparticles (CNPs) generated from a novel source (candle soot) as well as a unique perspective on the reactivity and degradation process of magic-sized cadmium chalcogenide nanocrystals. One potential application of CNPs is their use as an alternative fluorophore in a separation-based sensor system. Laser-induced-fluorescence (LIF) is a commonly used manner of detection in this type of platform, but is limited in many cases by problems associated with the fluorophore. Carbon-based nanoparticles have the potential to improve upon traditional fluorophores in applications that make use of LIF as the detection scheme. CNPs were extracted from the carbonaceous material produced by the incomplete combustion of a candle. The soot was submitted to an oxidizing treatment and extraction/filtration procedures rendering watersoluble luminescent species. Electron microscopy was used to identify globular, amorphous structures in the nanometer size-range. An aqueous suspension of CNPs demonstrated excellent stability in terms of its electronic properties, showing little change in absorption and emission spectra upon storage under ambient conditions over a two-year period. Capitalizing on the strengths of capillary electrophoresis (CE) as a characterization technique, we have analyzed the negatively-charged CNPs in terms of charge and size by studying the influence of variable CE conditions on the resulting separation. Separations at different pH revealed a highly complex mixture of CNPs, containing species with large

  19. The Eocene Rusayl Formation, Oman, carbonaceous rocks in calcareous shelf sediments: Environment of deposition, alteration and hydrocarbon potential

    Energy Technology Data Exchange (ETDEWEB)

    Dill, H.G.; Wehner, H.; Kus, J. [Federal Institute for Geosciences and Natural Resources, P.O. Box 510163, D-30631 Hannover (Germany); Botz, R. [University Kiel, Geological-Paleontological Department, Olshausenstrasse 40-60, D-24118 Kiel (Germany); Berner, Z.; Stueben, D. [Technical University Karlsruhe, Institute for Mineralogy and Geochemistry, Fritz-Haber-Weg 2, D-76131 Karlsruhe (Germany); Al-Sayigh, A. [Sultan Qaboos University, Geological Dept. PO Box 36, Al-Khod (Oman)

    2007-10-01

    incursions make up a greater deal of the sedimentary record than mangrove swamps. Terra rossa paleosols mark the end of accumulation of organic material (OM) and herald supratidal conditions at the passage of Rusayl Formation into the overlying Seeb Formation. In the subtidal-supratidal cycles of lithofacies unit VIII the terra rossa horizons are thining upwards and become gradually substituted for by deep-water middle ramp sediments of lithofacies unit IX. Framboidal pyrite, (ferroan) dolomite with very little siderite are indicative of an early diagenetic alteration stage I under rather moderate temperatures of formation. During a subsequent stage II, an increase in the temperature of alteration was partly induced by burial and a high heat flow from the underlying Semail Ophiolite. Type-III kerogen originating from higher plants and, in addition, some marine biota gave rise to the generation of small amounts of soluble organic matter during this stage of diagenesis. The average reflectance of humic particles marks the beginning of the oil window and the production index reveals the existence of free hydrocarbons. Further uplift of the Eocene strata and oxidation during stage IIII caused veins of satin spar to form from organic sulfur and pyrite in the carbonaceous material. Lowering of the pH value of the pore fluid led to the precipitation of jarosite and a set of hydrated aluminum sulfates dependant upon the cations present in the wall rocks. AMD minerals (= acid mine drainage) are not very widespread in this carbonaceous series intercalated among calcareous rocks owing to the buffering effect of carbonate minerals. These carbonate-hosted carbonaceous rocks are below an economic level as far as the mining of coal is concerned, but deserves particular attention as source rocks for hydrocarbons in the Middle East, provided a higher stage of maturity is reached. (author)

  20. ANALIZA NIEZAWODNOŚCI STACJI UZDATNIANIA WODY

    Directory of Open Access Journals (Sweden)

    Barbara TCHÓRZEWSKA-CIEŚLAK

    Full Text Available Systemy zbiorowego zaopatrzenia w wodę składają się z połączonych ze sobą elementów (podsystemów stanowiących integralna całość, współpracujących ze sobą w sposób ciągły w celu zapewnienia dla konsumentów wody o odpowiedniej jakości. W przypadku gdy jakość wody w źródle nie odpowiada normatywom stawianym wodzie przeznaczonej do spożycia przez ludzi, woda musi być poddana procesom uzdatniania. Niezawodność funkcjonowania stacji uzdatniania wody jest jednym z podstawowych elementów szeroko rozumianej analizy niezawodności i bezpieczeństwa całego systemu zbiorowego zaopatrzenia w wodę. Niezawodność dostawy wody polega na zapewnieniu stabilnych warunków, umożliwiających pokrycie bieżącego i perspektywicznego zapotrzebowania na wodę w odpowiedniej ilości i wymaganej jakości w dowolnym, dogodnym dla konsumentów wody czasie. W pracy przedstawiono podstawy analizy niezawodności, podano podstawowe miary oraz zasady wykorzystania struktur niezawodnościowych. Obliczenia wykonano dla stacji uzdatniania wody na podstawie schematu niezwodnościowego metodą jednoparametryczną. Na podstawie danych z eksploatacyjnych stacji uzdatniania wody (SUW wchodzącej w skład systemu zbiorowego zaopatrzenia w wodę miasta liczącego ok 80 tys. mieszkańców sporządzono schemat niewodności stacji oraz przeprowadzono obliczenia wskaźnika gotowości K. W metodzie wykorzystano podstawowe struktury niezawodnościowe. Wyznaczoną miarę niezawodności porównano z wartościami kryterialnymi.

  1. Language Practices in the Ci-Classroom

    DEFF Research Database (Denmark)

    Mourtou, Eleni

    2014-01-01

    Prelingually deafened children are nowadays likely to receive a cochlear implant (ci). As these children do their language acquisition with a cochlear implant they require a constant rehabilitation and support. Educational staff is instructed on how to work with children with ci in form of guidel......Prelingually deafened children are nowadays likely to receive a cochlear implant (ci). As these children do their language acquisition with a cochlear implant they require a constant rehabilitation and support. Educational staff is instructed on how to work with children with ci in form...... of guidelines and workshops. This paper discusses language practices used in the setting of a school for cochlear-implanted children. These children encounter language and pronunciation problems that accompany prelingual deafness and hearing with a cochlear implant. I examine two practices, which are used...... during the storytelling activity: repeat requests and questions. Whereas repeat requests are used in ci-therapy, questions have been shown to be instrumentalized for educational purposes in the setting of a school. I will reveal the educational/rehabilitational issues that are linked to these practices....

  2. The hydrocarbon potential, thermal maturity, sequence stratigraphic setting and depositional palaeoenvironment of carbonaceous shale and lignite successions of Panandhro, northwestern Kutch Basin, Gujarat, Western India

    Science.gov (United States)

    Sahay, Vinay

    2011-03-01

    The objective of the present paper is to provide geochemical and palynological data to characterize lignites and carbonaceous shales from Panandhro, northwestern Kutch Basin, Gujarat, Western India, in terms of their hydrocarbon potential, thermal maturity, sequence stratigraphic settings and depositional palaeoenvironment. The samples, collected in Panandhro lignite mine, belong to Naredi Formation of Late Paleocene-Early Eocene age. The geochemical results are based on proximate analysis, ultimate analysis, X-ray diffraction and Rock-Eval py-rolysis analyses, whereas palynological data include palynofossil composition and thermal alteration index (TAI). The TOC, hydrogen index (HI), cracked hydrocarbon (S2), bitumen index (BI), quality index (QI), and the total genetic potential (S1+S2) values indicate that the studied lignites and carbonaceous shales have good source rock potential. The organic matter is predominantly of type II and type II/III kerogen, which has potential to generate oil as well as gas. Thermal maturity determined from thermal alteration index (TAI), Tmax and production index (PI) indicates that the organic matter is immature, and in the diagenesis stage of organic matter transformation. The deposition of the studied carbonaceous shales and lignites took place in palaeoenvironments varying from brackish mangrove to freshwater swamp. This study indicates that the proportion of ferns, palms, volatile matter content, S/C, H/C ratios, as well as the presence of siderite and quartz can be used as an indicator of accommodation trends in the coal depositional system. The Panandhro carbonaceous shales and lignites were deposited during the lowstand systems tract with many cycles of small magnitude trangressive-regressive phases. Thus, the geochemistry and ecological palynology are useful not only for the investigation of coal quality and origin, but also to infer accommodation space settings of the mire. This can be gainfully utilized in the coal

  3. Agglomeration Determines Effects of Carbonaceous Nanomaterials on Soybean Nodulation, Dinitrogen Fixation Potential, and Growth in Soil

    Science.gov (United States)

    The potential effects of carbonaceous nanomaterials (CNMs) on agricultural plants are of concern. However, little research has been performed using plants cultivated to maturity in soils contaminated with various CNMs at different concentrations. Here, we grew soybean for 39 days...

  4. Diversity in C-Xanes Spectra Obtained from Carbonaceous Solid Inclusions from Monahans Halite

    Science.gov (United States)

    Kebukawa, Y.; Zolensky, M. E.; Fries, M.; Kilcoyne, A. L. D.; Rahman, Z.; Cody, G. D.

    2014-01-01

    Monahans meteorite (H5) contains fluid inclusion- bearing halite (NaCl) crystals [1]. Microthermometry and Raman spectroscopy showed that the fluid in the inclusions is an aqueous brine and they were trapped near 25degC [1]. Their continued presence in the halite grains requires that their incorporation into the H chondrite asteroid was post metamorphism [2]. Abundant solid inclusions are also present in the halites. The solid inclusions include abundant and widely variable organics [2]. Analyses by Raman microprobe, SEM/EDX, synchrotron X-ray diffraction and TEM reveal that these grains include macromolecular carbon similar in structure to CV3 chondrite matrix carbon, aliphatic carbon compounds, olivine (Fo99-59), high- and low-Ca pyroxene, feldspars, magnetite, sulfides, lepidocrocite, carbonates, diamond, apatite and possibly the zeolite phillipsite [3]. Here we report organic analyses of these carbonaceous residues in Monahans halite using C-, N-, and O- X-ray absorption near edge structure (XANES). Samples and Methods: Approximately 100 nm-thick sections were extracted with a focused ion beam (FIB) at JSC from solid inclusions from Monahans halite. The sections were analyzed using the scanning transmission X-ray microscope (STXM) on beamline 5.3.2.2 at the Advanced Light Source, Lawrence Berkeley National Laboratory for XANES spectroscopy. Results and Discussion: C-XANES spectra of the solid inclusions show micrometer-scale heterogeneity, indicating that the macromolecular carbon in the inclusions have complex chemical variations. C-XANES features include 284.7 eV assigned to aromatic C=C, 288.4-288.8 eV assigned to carboxyl, and 290.6 eV assigned to carbonate. The carbonyl features obtained by CXANES might have been caused by the FIB used in sample preparation. No specific N-XANES features are observed. The CXANES spectra obtained from several areas in the FIB sections include type 1&2 chondritic IOM like, type 3 chondritic IOM like, and none of the above

  5. Preparation of carbonaceous electrodes and evaluation of their performance by electrochemical techniques

    International Nuclear Information System (INIS)

    Sharma, H.S.; Manolkar, R.B.; Kamat, J.V.; Marathe, S.G.; Biswas, A.R.; Kulkarni, P.G.

    1994-01-01

    Carbonaceous electrodes, from glassy carbon (GC), graphite rod or graphite powder, have been prepared for coulometric and voltammetric investigation. Beaker type graphite electrode of larger surface area was used as working electrode for the analysis of uranium and plutonium in solution by coulometry. Results have shown usefulness of the electrode for both uranium and plutonium analysis. Thus the graphite electrode can be used in place of mercury for uranium analysis and in place of platinum gauze for plutonium analysis. GC electrode ( from French and Indian material ), graphite or carbon paste electrode of smaller surface area prepared here have also been found to give satisfactory performance as could be observed from cyclic voltammetric (cv) patterns for standard K 9 Fe(CN) 6 /K 4 Fe(CN) 6 redox system. Especially the GC electrode, (French) polished to 1μ finish with diamond paste gave very low values (1μ amp.) of background current in 1M KCl and the difference in cathodic and anodic peak potentials (δE values) was close to 60 mV from one electron transfer. Therefore the electrode can be used for various types of electrochemical studies relating to redox potentials, reaction mechanism, kinetic parameters etc. of different electrode processes. (author). 20 refs., 3 tabs., 10 figs., 8 photographs

  6. Effects of non-carbonaceous meteoritic extracts on the germination, growth and chlorophyll content of edible plants

    Science.gov (United States)

    Marcano, Vicente; Matheus, Paula; Cedeño, Cesyen; Falcon, Nelson; Palacios-Prü, Ernesto

    2005-10-01

    We have conducted an investigation on the effects that the extracts of a non-carbonaceous meteorite could have on the germination and growth of plants and the ability of non-carbonaceous meteoritic resource to serve as nutrient source for young plants of edible types. Selected plants were two dicotyledons ( Lycopersicon esculentum and Daucus carota) and one monocotyledon ( Zea mays). Solution cultures were developed using seeds, seedlings and seed-embryos. Meteoritic powder was obtained from the Vigirima mesosiderite, which was analyzed by X-ray diffraction and atomic absorption spectrometry (AAS). Results showed that extracts having variable concentrations of meteoritic matter favored an earlier germination in some plant species but the increase of the concentrations produced a decreased germination. However, total germination rate was higher in the presence of meteoritic extracts than in the presence of controls in the all species. A high metabolic yield in the protein synthesis was seen in dicotyledons utilizing Type-A and B extracts having concentrations of 4.16-8.33×10 3 mg l -1. Phaeophytinization index and chlorophyll a/b ratio, suggesting a negative effect of the heavy metals or acidic ions over the photosynthetic activity when extracts having high meteoritic concentrations were utilized. However, a higher chlorophyll (a) production in comparison to that of chlorophyll (b) was seen in extracts (Type-A and -B) with low concentrations of meteoritic matter. On the other hand, Z. mays seed-embryos growing in extracts (Type-D) having 3.53×10 4 mg l -1 of meteoritic matter showed a protein production (9.81×10 -2 mg protein mg wet wt -1) higher than that observed in seed-embryos coming from extracts having lower concentrations. However, in Murashige medium, the seed-embryos exhibited a enhanced growth and a relatively higher protein production (10.3×10 -2 mg protein mg wet wt. -1). Further, chlorophyll (a+b) synthesis was higher in Murashige medium than in

  7. Evaluation of early Archean volcaniclastic and volcanic flow rocks as possible sites for carbonaceous fossil microbes.

    Science.gov (United States)

    Walsh, Maud M

    2004-01-01

    Sedimentary rocks have traditionally been the focus of the search for Archean microfossils; the Earth's oldest fossil bacteria are associated with carbonaceous matter in sedimentary cherts in greenstone belts in the eastern Pilbara block of Western Australia and Barberton greenstone belt of South Africa. Reports of possible fossils in a martian meteorite composed of igneous rock and the discovery of modern bacteria associated with basalts have stimulated a new look at Archean volcanic rocks as possible sites for fossil microbes. This study examines silicified volcaniclastic rocks, near-surface altered volcanic flow rocks, and associated stromatolite- like structures from the Archean Barberton greenstone belt to evaluate their potential for the preservation of carbonaceous fossils. Detrital carbonaceous particles are widely admixed with current-deposited debris. Carbonaceous matter is also present in altered volcanic flow rocks as sparse particles in silica veins that appear to be fed by overlying carbonaceous chert layers. Neither microfossils nor mat-like material was identified in the altered volcanic rocks or adjacent stromatolite-like structures. Ancient volcanic flow and volcaniclastic rocks are not promising sites for carbonaceous fossil preservation.

  8. On the Q-phase of carbonaceous chondrites

    International Nuclear Information System (INIS)

    Vis, R.D.; Heymann, D.

    1999-01-01

    One of the unresolved puzzles of meteoritics is the nature of the carrier of the so-called heavy planetary gases. Apparently, these gases reside mainly in a minor fraction, which has been dubbed Q by Lewis et al. [R.S. Lewis, B. Srinivasan, E. Anders, Science 190 (1975) 1251] in analogy of the naming by Papanastasiou et al. [D.A. Papanastassiou, G.J. Wasserburg, Earth Planet. Sci. Lett. 11 (1971) 37] of a minor glassy phase in lunar rocks highly enriched in trace elements such as Pb and U. Q stands for the archaic term quintessence, the fifth or last and highest substance in ancient and medieval philosophy above fire, air, water and earth. In this contribution, an attempt is made to provide evidence that Q is carbonaceous, with carbon in the form of closed structures such as carbon nanotubes which serve as micro bottles for the heavy noble gases. To this end, Q was characterised with micro-PIXE and NRA, whereas HREM was used to search for nanotubes. Q itself was obtained as residue after chemical destruction of samples of Allende, Leoville and Vigarano

  9. Primordial Molecular Cloud Material in Metal-Rich Carbonaceous Chondrites

    Science.gov (United States)

    Taylor, G. J.

    2016-03-01

    The menagerie of objects that make up our Solar System reflects the composition of the huge molecular cloud in which the Sun formed, a late addition of short-lived isotopes from an exploding supernova or stellar winds from a neighboring massive star, heating and/or alteration by water in growing planetesimals that modified and segregated the primordial components, and mixing throughout the Solar System. Outer Solar System objects, such as comets, have always been cold, hence minimizing the changes experienced by more processed objects. They are thought to preserve information about the molecular cloud. Elishevah Van Kooten (Natural History Museum of Denmark and the University of Copenhagen) and co-authors in Denmark and at the University of Hawai'i, measured the isotopic compositions of magnesium and chromium in metal-rich carbonaceous chondrites. They found that the meteorites preserve an isotopic signature of primordial molecular cloud materials, providing a potentially detailed record of the molecular cloud's composition and of materials that formed in the outer Solar System.

  10. CARES: Carbonaceous Aerosol and Radiative Effects Study Operations Plan

    Energy Technology Data Exchange (ETDEWEB)

    Zaveri, RA; Shaw, WJ; Cziczo, DJ

    2010-07-12

    The CARES field campaign is motivated by the scientific issues described in the CARES Science Plan. The primary objectives of this field campaign are to investigate the evolution and aging of carbonaceous aerosols and their climate-affecting properties in the urban plume of Sacramento, California, a mid-size, mid-latitude city that is located upwind of a biogenic volatile organic compound (VOC) emission region. Our basic observational strategy is to make comprehensive gas, aerosol, and meteorological measurements upwind, within, and downwind of the urban area with the DOE G-1 aircraft and at strategically located ground sites so as to study the evolution of urban aerosols as they age and mix with biogenic SOA precursors. The NASA B-200 aircraft, equipped with the High Spectral Resolution Lidar (HSRL), digital camera, and the Research Scanning Polarimeter (RSP), will be flown in coordination with the G-1 to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties, and to provide the vertical context for the G-1 and ground in situ measurements.

  11. Shock effects on hydrous minerals and implications for carbonaceous meteorites

    Science.gov (United States)

    Lange, M. A.; Ahrens, T. J.; Lambert, P.

    1985-01-01

    The effect of shock loading over the pressure range of 29-59 GPa on the shock-recovered specimens of antigorite serpentine, Mg3Si2O5(OH)4, were investigated employing infrared (IR) spectroscopy, thermogravimetric analysis, and optical and scanning electron microscopy. With increasing shock pressure, there was an increase in H2O IR absorption peaks at the expense of OH peaks, while the changes in SiO bond vibration modes were identical to those seen for other, nonhydrous minerals. Thermogravimetric results on vented assembly samples showed linear relationships between the shock pressure and both the length of dehydration interval and the effective activation energy for releasing post-shock structural water. Optical and scanning electron microscopy revealed gas bubbles, which appeared to be injected into zones of partial melting, and vesicular dark veins distributed throughout the shocked samples. It is suggested that shock loading of hydrous minerals would release and redistribute free water in the regoliths of carbonaceous chondrite parent bodies, giving rise to observed hydrous alterations.

  12.  Spis treści

    Directory of Open Access Journals (Sweden)

    Mieczysław Dobija

    2014-04-01

    Full Text Available  Od Zespołu Redakcyjnego ............................................................................... 5 Mieczysław Dobija – Rachunkowość w systemie pomiaru aktywności ekonomicznej państwa – Accounting as part of an economic activity measurement system ............... 7 Renata Dyląg, Ewelina Puchalska – Raportowanie zagadnień środowiskowych i społecznych – Reporting on social and environmental issues .............................................. 23 Jacek Gad – Sprawozdanie z wyniku całościowego jako źródło informacji na temat kapitałowych przychodów i kosztów – doświadczenia polskiego i niemieckiego rynku kapitałowego – Statement of comprehensive income as a source of information on capital income and expenses – experience of Polish and German capital markets...... 47 Piotr Luty – Ocena kondycji finansowej łączących się spółek na przykładzie jednostek z wybranych województw Polski Zachodniej – Assessment of financial position of merging companies based on selected provinces of Western Poland ............................................................................ 69 Irena Sobańska – Znaczenie dorobku naukowego Profesor Elżbiety Burzym dla rozwoju nauki i praktyki rachunkowości w Polsce – The importance of Professor Elżbieta Burzym’s contribution to the development of accounting theory, research and practice in Poland ........................ 83 Arleta Szadziewska – Rachunkowość jako źródło informacji na temat realizacji strategii społecznej odpowiedzialności biznesu – Accounting as a source of information for CSR strategy ............................. 95 Halina Waniak-Michalak – Informacja o pracy wolontariuszy w sprawozdaniach organizacji pożytku publicznego w Polsce – Information on volunteer labour in reports of public benefit organizations in Poland ............................................................................................................ 125

  13. Cognitivismo e ciência cognitiva

    Directory of Open Access Journals (Sweden)

    Marcos Barbosa de Oliveira

    1990-01-01

    Full Text Available O objetivo da comunicação é caracterizar uma escola de pensamento-o cognitivismo-e a disciplina a que ela deu origem. Depois de um breve apanhado das origens do cognitivismo descrevem-se os princípios ontológicos e metodológicos que o definem. Mostra-se a seguir a relação que há entre os computadores e a idéia funcionalista de considerar a mente como um sistema cujos elementos são caracterizados por suas funções, e não por sua constituição material. Discute-se finalmente a natureza e o nome da disciplina gerada pelo cognitivismo, sugerindo-se que se trata de uma proto-ciência, a qual deve ser denominada "Estudos Cognitivos" de preferência a "Ciência Cognitiva".

  14. Isotopic diversity in nebular dust: The distribution of Ti isotopic anomalies in carbonaceous chondrites

    International Nuclear Information System (INIS)

    Niemeyer, S.

    1988-01-01

    Average Ti isotopic patterns are derived for each class of carbonaceous chondrite from a chemically characterized suite of whole-rock samples. There is a well-resolved excess of 50 Ti in a subset of CI meteorites. Mean values of the 50 Ti excess for the four classes span a range of only 2 ε-units, with an apparent positive correlation with Al content. Previous evidence for anomalies in chondrules is augmented here by demonstrating that: (1) the more pristine Ca-Al-rich inclusions (CAIs) in Efremovka show the same isotopic pattern as the typical Allende CAI; and, (2) CM and CV matrix carry 50 Ti excesses of about 2 ε-units. The distribution of Ti isotopic anomalies among matrix, chondrules, and CAIs suggests a model in which all three constituents formed from precursor-assemblages in which some chemical memories were still intact; the isotopic differences reflect fractionations among the carrier phases of the different isotopic components. Chondrules formed by a mostly closed-system melting of their precursors, and thus provide a recording of the extent of nebular heterogeneity on the mg-size scale. The larger anomalies in CAIs, compared to matrix and most (but not all) chondrules, are attributed primarily to an open- rather than closed-system processing of the CAI precursors. Precursors of both FUN and normal CAIs experienced an episode of intense processing, perhaps partial melting, that created the FUN characteristics, but for normal CAIs the FUN effects were erased by subsequent isotopic equilibration and exchange

  15. Kierunki zmiansprawozdawczości finansowej

    Directory of Open Access Journals (Sweden)

    Zbigniew Luty

    2010-05-01

    Full Text Available W artykule wskazano na możliwe kierunki zmian w sprawozdawczości finansowej w najbliższych latach. Wymieńmy najważniejsze: 1 bazą jest informacja oparta na dokumentacji księgowej w ujęciu historycznym, 2 sprawozdania celowe (dedykowane, 3 informacja finansowa jako towar na specyficznym rynku sprawozdań, 4 prawo bilansowe tworzone z minimalnym wpływem lobbingu inwestorów.

  16. Fé perceptiva, filosofia e ciência

    Directory of Open Access Journals (Sweden)

    Adilson Xavier da Silva

    2010-09-01

    Full Text Available O objetivo de nosso artigo é compreender as noções de fé perceptiva, filosofia e ciência em Le visible et l’invisible (1964. Essas noções nos devem levar a um dos pontos fundamentais do pensamento merleau-pontyano, em que a interrogaçáo ontológica parte essencialmente da fé perceptiva para chegar a uma ontologia da carne.

  17. Combustion and Performance Characteristics of CI Engine Running with Biodiesel

    OpenAIRE

    Tesfa, Belachew; Mishra, Rakesh; Gu, Fengshou; Ball, Andrew

    2013-01-01

    Biodiesel is one of the alternative fuels which is renewable and environmentally friendly and can be used in diesel engines with little or no modifications. In the present study, experimental investigations were carried out on the effects of biodiesel types, biodiesel fraction and physical properties on the combustion and performance characteristics of a compression ignition (CI) engine. The experimental work was conducted on a four-cylinder, four -stroke, direct injection (DI) and turbocharg...

  18. Redistribution of Sr and rare earth elements in the matrices of CV3 carbonaceous chondrites during aqueous alteration in their parent body

    Science.gov (United States)

    Jogo, Kaori; Ito, Motoo; Nakamura, Tomoki; Kobayashi, Sachio; Lee, Jong Ik

    2018-03-01

    We measured the abundances of Sr and rare earth elements (REEs) in the matrices of five CV3 carbonaceous chondrites: Meteorite Hills (MET) 00430, MET 01070, La Paz ice field (LAP) 02206, Asuka (A) 881317 and Roberts Massif (RBT) 04143. In the MET 00430 and MET 01074 matrices, the Sr/CI and light REE (LREE, La-Nd)/CI ratios positively correlate with the amounts of Ca-rich secondary minerals, which formed during aqueous alteration in the CV3 chondrite parent body. In contrast, in the LAP 02206 and RBT 04143 matrices, although the Sr/CI ratios correlate with the amounts of Ca-rich secondary minerals, the LREE/CI ratios vary independently from the amounts of any secondary minerals. This suggests that the LREE/CI ratios in these matrices were produced prior to the parent body alteration, probably in the solar nebula. The LREE/CI ratios of the LAP 02206 and RBT 04143 matrices reveal the mixing process of matrix minerals prior to the accretion of the CV3 chondrite parent body. The mixing degrees of matrix minerals might be different between these two matrices. Because solid materials would be mixed over time according to the radial diffusion model of a turbulent disk, the matrix minerals consisting of LAP 02206 and RBT 04143 matrices might be incorporated into their parent body with different timing.

  19. An analysis of vowel harmony in ciNsenga and ciCewa: A ...

    African Journals Online (AJOL)

    This article presents an analysis of vowel harmony that occurs in the verbal system of ciNsenga and ciCewa. In these languages the nature of suffix vowels is determined by the nature of the root: mid vowels trigger the vowel /ε/ on the suffixes, non-mid vowels, on the other hand, trigger the vowel /i/ on the suffixes.

  20. Thermal investigation of tetrafunctional epoxy resin filled with different carbonaceous nanostructures

    Science.gov (United States)

    Romano, Vittorio; Naddeo, Carlo; Vertuccio, Luigi; Lafdi, Khalid; Guadagno, Liberata

    2016-05-01

    This paper presents a preliminary investigation of thermal behaviour of epoxy nanocomposites containing different types of nanofillers, such as 1-D Multiwall Carbon Nanotubes (MWCNTs) and 2-D predominant shape of Exfoliated Graphite nanoparticles (EG). The cure behavior of the different epoxy formulations (filled and unfilled) was studied by Differential Scanning Calorimetry (DSC). The DSC technique is particularly advantageous for studying the cure of reactive epoxy systems because the curing process is accompanied by the liberation of heat. For all the epoxy nanocomposites analyzed in this work, Differential Scanning Calorimetry (DSC) investigation shows curing degree (DC) values higher than 92% for the curing cycle up to 200°C, reaching up to 100% for the samples filled with Exfoliated Graphite nanoparticles (EG). The calorimetric results also show that Exfoliated Graphite nanoparticles accelerate the curing process of the epoxy resin of about 20°C. Transient Plane Source measurements of thermal conductivity show that this acceleration is directly related to the better heat conduction obtained through the incorporation in the epoxy matrix of carbonaceous nanostructures with predominantly two-dimensional shape (Exfoliated Graphite nanoparticles). The experimental results clearly demonstrate that the use of graphene sheets is very hopeful for obtaining nanocomposites characterized by high performance that are able to meet the ambitious requirements in the aeronautical field.

  1. Analytical electron microscopy of fine-grained phases in primitive interplanetary dust particles and carbonaceous chondrites

    Science.gov (United States)

    Mackinnon, Ian D. R.; Rietmeijer, Frans J. M.; Mckay, David S.

    1987-01-01

    In order to describe the total mineralogical diversity within primitive extraterrestrial materials, individual interplanetary dust particles (IDPs) collected from the stratosphere as part of the JSC Cosmic Dust Curatorial Program were analyzed using a variety of AEM techniques. Identification of over 250 individual grains within one chondritic porous (CP) IDP shows that most phases could be formed by low temperature processes and that heating of the IDP during atmospheric entry is minimal and less than 600 C. In a review of the mineralogy of IDPs, it was suggested that the occurrence of other silicates such as enstatite whiskers is consistent with the formation in an early turbulent period of the solar nebula. Experimental confirmation of fundamental chemical and physical processes in a stellar environment, such as vapor phase condensation, nucleation, and growth by annealing, is an important aspect of astrophysical models for the evolution of the Solar System. A detailed comparison of chondritic IDP and carbonaceous chondrite mineralogies shows significant differences between the types of silicate minerals as well as the predominant oxides.

  2. AMMONIA IN THE EARLY SOLAR SYSTEM: AN ACCOUNT FROM CARBONACEOUS METEORITES

    International Nuclear Information System (INIS)

    Pizzarello, S.; Williams, L. B.

    2012-01-01

    This study presents a survey of abundance distribution and isotopic composition of the ammonia found incorporated in the kerogen-like insoluble material of selected carbonaceous chondrite meteorites; the ammonia was released upon hydrothermal treatment at 300°C and 100 MPa. With the exception of Allende, a metamorphosed and highly altered stone, all the insoluble organic materials (IOM) of the meteorites analyzed released significant amounts of ammonia, which varied from over 4 μg mg –1 for the Orgueil IOM to 0.5 μg mg –1 for that of Tagish Lake; the IOM of the pristine Antarctica find GRA95229 remains the most rich in freeable ammonia with 10 μg mg –1 . While the amounts of IOM bound ammonia do not appear to vary between meteorites with a recognizable trend, a possible consequence of long terrestrial exposure of some of the stones, we found that the δ 15 N composition of the ammonia-carrying materials is clearly distinctive of meteorite types and may reflect a preservation of the original 15 N distribution of pre- and proto-solar materials.

  3. Analytical electron microscopy of fine-grained phases in primitive interplanetary dust particles and carbonaceous chondrites

    International Nuclear Information System (INIS)

    Mackinnon, I.D.R.; Rietmeijer, F.J.M.; Mckay, D.S.

    1987-01-01

    In order to describe the total mineralogical diversity within primitive extraterrestrial materials, individual interplanetary dust particles (IDPs) collected from the stratosphere as part of the JSC Cosmic Dust Curatorial Program were analyzed using a variety of AEM techniques. Identification of over 250 individual grains within one chondritic porous (CP) IDP shows that most phases could be formed by low temperature processes and that heating of the IDP during atmospheric entry is minimal and less than 600 C. In a review of the mineralogy of IDPs, it was suggested that the occurrence of other silicates such as enstatite whiskers is consistent with the formation in an early turbulent period of the solar nebula. Experimental confirmation of fundamental chemical and physical processes in a stellar environment, such as vapor phase condensation, nucleation, and growth by annealing, is an important aspect of astrophysical models for the evolution of the Solar System. A detailed comparison of chondritic IDP and carbonaceous chondrite mineralogies shows significant differences between the types of silicate minerals as well as the predominant oxides

  4.  Spis treści

    Directory of Open Access Journals (Sweden)

    ANNA BARTOSZEWICZ

    2015-03-01

    Full Text Available  Od Zespołu Redakcyjnego – Editorial .......................................................................................................... 7 Anna Bartoszewicz – Praktyczna realizacja Programu zapewnienia i poprawy jakości w komórkach audytu wewnętrznego na wybranych przykładach – Implementation of Quality Assurance and Improvement Program by internal audit teams on selected examples ................................................................ 9 Anna Białek-Jaworska, Natalia Nehrebecka – Struktura kapitałowa przedsiębiorstw w świetle wyników badań – Capital structure of companies in the light of research results ..................... 29 Magda Chraścina – Determinanty tworzenia rezerw oraz ich skutki bilansowo- -wynikowe na przykładzie spółek notowanych na Giełdzie Papierów Wartościowych w Warszawie – Determinants of creating provisions and their effect on the balance sheet and income statement on the example of companies listed on the Warsaw Stock Exchange .................................................................................................. 53 Małgorzata Garstka – Dobry obyczaj jako norma kształtująca zachowanie księgowych – Good practice as a norm shaping the behavior of accountants ...................... 73 Przemysław Kabalski, Joanna Szwajcar – Feminizacja studiów w zakresie rachunkowości w Polsce – przyczyny i skutki – Feminization of accounting studies in Poland – causes and consequences .. 85 Anna Kasperowicz – Znaki i kody rachunkowości w procesie komunikacji – Accounting signs and codes in the communication process .......................... 107 Marcin Kędzior – Dobrowolne stosowanie MSSF przez spółki giełdowe w wybranych krajach Europy Zachodniej – Voluntary adoption of IFRS by listed companies in selected Western European countries ................................................................................................. 123 Ewelina Zarzycka

  5. Influence of Electric Fields on Biofouling of Carbonaceous Electrodes.

    Science.gov (United States)

    Pandit, Soumya; Shanbhag, Sneha; Mauter, Meagan; Oren, Yoram; Herzberg, Moshe

    2017-09-05

    Biofouling commonly occurs on carbonaceous capacitive deionization electrodes in the process of treating natural waters. Although previous work reported the effect of electric fields on bacterial mortality for a variety of medical and engineered applications, the effect of electrode surface properties and the magnitude and polarity of applied electric fields on biofilm development has not been comprehensively investigated. This paper studies the formation of a Pseudomonas aeruginosa biofilm on a Papyex graphite (PA) and a carbon aerogel (CA) in the presence and the absence of an electric field. The experiments were conducted using a two-electrode flow cell with a voltage window of ±0.9 V. The CA was less susceptible to biofilm formation compared to the PA due to its lower surface roughness, lower hydrophobicity, and significant antimicrobial properties. For both positive and negative applied potentials, we observed an inverse relationship between biofilm formation and the magnitude of the applied potential. The effect is particularly strong for the CA electrodes and may be a result of cumulative effects between material toxicity and the stress experienced by cells at high applied potentials. Under the applied potentials for both electrodes, high production of endogenous reactive oxygen species (ROS) was indicative of bacterial stress. For both electrodes, the elevated specific ROS activity was lowest for the open circuit potential condition, elevated when cathodically and anodically polarized, and highest for the ±0.9 V cases. These high applied potentials are believed to affect the redox potential across the cell membrane and disrupt redox homeostasis, thereby inhibiting bacterial growth.

  6. Observationally constrained estimates of carbonaceous aerosol radiative forcing.

    Science.gov (United States)

    Chung, Chul E; Ramanathan, V; Decremer, Damien

    2012-07-17

    Carbonaceous aerosols (CA) emitted by fossil and biomass fuels consist of black carbon (BC), a strong absorber of solar radiation, and organic matter (OM). OM scatters as well as absorbs solar radiation. The absorbing component of OM, which is ignored in most climate models, is referred to as brown carbon (BrC). Model estimates of the global CA radiative forcing range from 0 to 0.7 Wm(-2), to be compared with the Intergovernmental Panel on Climate Change's estimate for the pre-Industrial to the present net radiative forcing of about 1.6 Wm(-2). This study provides a model-independent, observationally based estimate of the CA direct radiative forcing. Ground-based aerosol network data is integrated with field data and satellite-based aerosol observations to provide a decadal (2001 through 2009) global view of the CA optical properties and direct radiative forcing. The estimated global CA direct radiative effect is about 0.75 Wm(-2) (0.5 to 1.0). This study identifies the global importance of BrC, which is shown to contribute about 20% to 550-nm CA solar absorption globally. Because of the inclusion of BrC, the net effect of OM is close to zero and the CA forcing is nearly equal to that of BC. The CA direct radiative forcing is estimated to be about 0.65 (0.5 to about 0.8) Wm(-2), thus comparable to or exceeding that by methane. Caused in part by BrC absorption, CAs have a net warming effect even over open biomass-burning regions in Africa and the Amazon.

  7. Carbonaceous characteristics of atmospheric particulate matter in Hong Kong.

    Science.gov (United States)

    Ho, K F; Lee, S C; Yu, Jimmy C; Zou, S C; Fung, Kochy

    2002-12-02

    To determine the characteristic of carbonaceous species in atmospheric particles in Hong Kong, PM10 and PM2.5 samples were collected using high volume (hi-vol.) air samplers from November 2000 to February 2001. The organic carbon (OC) and elemental carbon (EC) were analyzed by the selective thermal manganese dioxide oxidation (TMO) method. The ratios of PM2.5/PM10 mass ratios were 0.61, 0.78 and 0.53 for particulate matter collected at PolyU station (PolyU, near a major traffic corridor), Kwun Tong station (KT, mixed residential/commercial/industrial) and the Hok Tsui background station (HT), respectively. These results indicate that the PM2.5 concentrations constitute the majority of the PM10) concentrations, especially in urban and industrial areas of Hong Kong. The average concentrations at the three sites ranged from 73.11 to 83.52 microg/m3 for PM10 and from 42.37 to 57.38 microg/m3 for PM2.5. The highest daily mass concentrations of PM10 and PM2.5 were 125.89 microg/m3 and 116.89 microg/m3 at KT, respectively. The correlation between PM10 and PM2.5 was high at KT and HT (r > 0.9, P Hong Kong. OC/EC ratios for PM10 and PM2.5 were less than 2 at PolyU and KT stations while the ratio exceeded 3 at HT background station. This indicates that OC measured in the urban area may be emitted directly as a primary aerosol.

  8. Analyses and characterization of fossil carbonaceous materials for silicon production

    Energy Technology Data Exchange (ETDEWEB)

    Myrvaagnes, Viktor

    2008-01-15

    Production of high silicon alloys is carried out in submerged arc furnaces by reduction of silicon bearing oxides (typically quartz) with carbon materials. Carbonaceous materials like coal, coke, charcoal and woodchips are commonly used as reduction materials in the process. Primarily based on historical prices of charcoal compared to fossil reduction materials, the Norwegian Ferroalloy Industry has mostly been using coal and coke (char) as the source of carbon. From a process point of view, the most important role of the carbonaceous material is to react with SiO gas to produce SiC. The ability of the reduction materials to react with SiO gas can be measured and the value is recognized as the reactivity of the carbon source. Reactivity is one of the most important parameters in the smelting process and is commonly acknowledged to strongly affect both productivity and specific energy consumption. The main objectives of this work has been to establish methods to characterize the material properties of fossil carbonaceous reduction materials used in the silicon process and to evaluated how these properties affect the reactivity towards SiO gas. In order to accomplish these objectives, three run of mine (ROM) single seam coals which are particularly well suited for ferroalloy production were selected. Two Carboniferous coals from USA (Blue Gem) and Poland (Staszic) with similar rank, but significantly different composition as well as a Permian coal from Australia (Peak Downs) have been characterized by chemical- and petrographical methods. Blue Gem is a homogeneous coal, low in mineral inclusions and macerals of the inertinite group and determined to have a random vitrinite reflectance of 0.71 %. Staszic has a similar reflectance of vitrinite (0.72 %), but is determined to be a very inhomogeneous coal with both inertinite macerals and minerals embedded in the vitrinite matrix. Peak Downs has a random reflectance of vitrinite of 1.32 % and is hence the coal sample of

  9. Carbonaceous species and humic like substances (HULIS) in Arctic snowpack during OASIS field campaign in Barrow

    Science.gov (United States)

    Voisin, Didier; Jaffrezo, Jean-Luc; Houdier, StéPhan; Barret, Manuel; Cozic, Julie; King, Martin D.; France, James L.; Reay, Holly J.; Grannas, Amanda; Kos, Gregor; Ariya, Parisa A.; Beine, Harry J.; Domine, Florent

    2012-07-01

    Snowpacks contain many carbonaceous species that can potentially impact on snow albedo and arctic atmospheric chemistry. During the OASIS field campaign, in March and April 2009, Elemental Carbon (EC), Water insoluble Organic Carbon (WinOC) and Dissolved Organic Carbon (DOC) were investigated in various types of snow: precipitating snows, remobilized snows, wind slabs and depth hoars. EC was found to represent less than 5% of the Total Carbon Content (TCC = EC + WinOC + DOC), whereas WinOC was found to represent an unusual 28 to 42% of TCC. Snow type was used to infer physical processes influencing the evolution of different fractions of DOC. DOC is highest in soil influenced indurated depth hoar layers due to specific wind related formation mechanisms in the early season. Apart from this specific snow type, DOC is found to decrease from precipitating snow to remobilized snow to regular depth hoar. This decrease is interpreted as due to cleaving photochemistry and physical equilibration of the most volatile fraction of DOC. Depending on the relative proportions of diamond dust and fresh snow in the deposition of the seasonal snowpack, we estimate that 31 to 76% of DOC deposited to the snowpack is reemitted back to the boundary layer. Under the assumption that this reemission is purely photochemical, we estimate an average flux of VOC out of the snowpack of 20 to 170 μgC m-2 h-1. Humic like substances (HULIS), short chain diacids and aldehydes are quantified, and showed to represent altogether a modest (<20%) proportion of DOC, and less than 10% of DOC + WinOC. HULIS optical properties are measured and could be consistent with aged biomass burning or a possible marine source.

  10. Kuhn e as ciências sociais

    Directory of Open Access Journals (Sweden)

    Jesus de Paula Assis

    1993-12-01

    Full Text Available No texto, são expostos os motivos básicos pelos quais o vocabulário emprestado de Thomas Kuhn - notadamente o termo paradigma - e o modelo de desenvolvimento científico exposto pelo autor em seu A estrutura das revoluções científicas foram tomados de empréstimo em textos que discutem a epistemologia das ciências sociais. A conclusão é que as supostas aplicações do modelo kuhniano às ciências sociais se baseiam em leitura que não encontra qualquer apoio no autor e, principalmente, obscurecem as implicações mais amplas de sua obra.The article shows for what reasons the vocabulary and the model for scientific growth of Thomas Kuhn were borrowed by epistemologists of the social sciences. The conclusion is that the texts produced in this vein are based in a shallow understanding of the author's main implications.

  11. Preparation and characterization of a new carbonaceous material for electrochemical systems

    Directory of Open Access Journals (Sweden)

    ZI JI LIN

    2010-02-01

    Full Text Available A new carbonaceous material was successfully prepared by the py-rolysis of scrap tire rubber at 600 °C under a nitrogen atmosphere. The physical characteristics of the prepared carbonaceous material were studied by scanning electron microscopy (SEM, X-ray powder diffraction (XRD and X-ray photoelectron spectroscopy (XPS. It was proved that the carbonaceous material had a disordered structure and spherical morphology with an average particle size about 100 nm. The prepared carbonaceous material was also used as electrodes in electrochemical systems to examine its electrochemical performances. It was demonstrated that it delivered a lithium insertion capacity of 658 mA h g-1 during the first cycle with a coulombic efficiency of 68 %. Cyclic voltammograms test results showed that a redox reaction occurred during the cycles. The chemical diffusion coefficient based on the impedance diagram was about 10-10 cm2 s-1. The pyrolytic carbonaceous material derived from scrap tire rubber is therefore considered to be a potential anode material in lithium secondary batteries or capacitors. Furthermore, it is advantageous for environmental protection.

  12. Reactive Oxygen-Doped 3D Interdigital Carbonaceous Materials for Li and Na Ion Batteries.

    Science.gov (United States)

    Fan, Ling; Lu, Bingan

    2016-05-01

    Carbonaceous materials as anodes usually exhibit low capacity for lithium ion batteries (LIBs) and sodium ion batteries (SIBs). Oxygen-doped carbonaceous materials have the potential of high capacity and super rate performance. However, up to now, the reported oxygen-doped carbonaceous materials usually exhibit inferior electrochemical performance. To overcome this problem, a high reactive oxygen-doped 3D interdigital porous carbonaceous material is designed and synthesized through epitaxial growth method and used as anodes for LIBs and SIBs. It delivers high reversible capacity, super rate performance, and long cycling stability (473 mA h g(-1) after 500 cycles for LIBs and 223 mA h g(-1) after 1200 cycles for SIBs, respectively, at the current density of 1000 mA g(-1) ), with a capacity decay of 0.0214% per cycle for LIBs and 0.0155% per cycle for SIBs. The results demonstrate that constructing 3D interdigital porous structure with reactive oxygen functional groups can significantly enhance the electrochemical performance of oxygen-doped carbonaceous material. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Wycena należności kredytowycha standardy sprawozdawczości finansowej

    Directory of Open Access Journals (Sweden)

    Izabela Emerling

    2009-12-01

    Full Text Available Jednym z najistotniejszych obszarów działalności banków komercyjnych jest działalność kredytowa, której sposób ujęcia w księgach rachunkowych i sprawozdaniach finansowych determinuje obraz sytuacji majątkowej i finansowej odzwierciedlony w sprawozdawczości finansowej banku komercyjnego. Podstawowym celem artykułu jest zbadanie ujęcia w sprawozdaniach finansowych banków komercyjnych różnych form działalności kredytowej i ich metod wyceny. Zastosowanie różnych metod wyceny bilansowej wierzytelności kredytowych wpływa na obraz sytuacji majątkowej i finansowej banku komercyjnego.

  14. Ciência Cognitiva e Ciência da Informação: paralelos

    OpenAIRE

    Andalécio, Aleixina Lopes; UFMG; Souza, Renato Rocha; ECI/UFMG

    2008-01-01

    Apresenta teorias sobre o desenvolvimento cognitivo e abordagens sobre a aquisição do conhecimento. Relaciona essas abordagens com os modelos da Ciência da Informação, e analisa a aquisição do conhecimento. Sugere o desenvolvimento de um trabalho multidisciplinar entre as áreas Cognição e Ciência da Informação, que permita uma linguagem comum entre as áreas.

  15. Natureza e ciências sociais

    Directory of Open Access Journals (Sweden)

    Gloria Maria Vargas

    2003-12-01

    Full Text Available A construção do sentido do termo natureza abrange diferentes áreas do conhecimento e tem sido objeto de reflexão tanto das ciências naturais quanto sociais. Nos desdobramentos do conhecimento produzido sobre esta temática existem diversas abordagens que, da perspectiva das ciências sociais, podem ser identificadas. O propósito deste artigo é considerar algumas dessas abordagens e relacioná-las com as novas práticas sociais que determinam formas de intervenção inéditas sobre a natureza, e que colocam questões para estas ciências, enquanto produtoras de conhecimento sobre o tema. De igual forma, explicita-se a substituição deste termo pelo de ambiente e, posteriormente, o aparecimento do desenvolvimento sustentável, como parte do cabedal conceitual com que a problemática em torno das relações naturezasociedade é abordada nas ciências sociais.La construcción del sentido del término naturaleza abarca diferentes áreas del conocimiento y ha sido objeto de reflexión tanto de las ciencias naturales como sociales. Los desdoblamientos del conocimiento producido sobre este tema muestran que existen diversos abordajes que pueden ser identificados desde la perspectiva de las ciencias sociales. El objetivo de este artículo es considerar algunos de esos abordajes y relacionarlos con las nuevas prácticas sociales que determinan formas de intervención inéditas sobre la naturaleza y que sugieren cuestionamientos para estas ciencias, como productoras de conocimiento sobre este tema. De igual manera, se explicita la substitución de este término por el de ambiente e, posteriormente, el aparecimiento del término desarrollo sostenible como parte del acervo conceptual con que es abordada la problemática alrededor de las relaciones naturaleza-sociedad en las ciencias sociales.The construction of the term nature involves different areas of knowledge and has been the object of inquiry of both natural and social sciences. The knowledge

  16. Magnetization of a Single Carbonaceous Grain Obtained by Field-Induced Acceleration

    Science.gov (United States)

    Hisayoshi, Keiji; Uyeda, Chiaki

    2017-10-01

    Diamagnetic susceptibility χDIA of single carbonaceous grains were detected by observing their translations induced by field-gradient force in an area of microgravity. Using the above method, χDIA of a small carbonaceous particle is obtained with no interfering signal of the sample holder; it is unnecessary to know the mass of sample. The χDIA values of various materials obtained by the above method agreed fairly well with their published values. By comparing the obtained χDIA value with a list of published values, the material of an unidentified organic grain can be determined without consuming the sample. The principle of magnetic transition is applicable to investigate the magnetic properties of nano-size carbonaceous materials.

  17. Preparation of a Sulfonated Carbonaceous Material from Lignosulfonate and Its Usefulness as an Esterification Catalyst

    Directory of Open Access Journals (Sweden)

    Duckhee Lee

    2013-07-01

    Full Text Available Sulfonated carbonaceous material useful as a solid acid catalyst was prepared from lignosulfonate, a waste of the paper-making industry sulfite pulping process, and characterized by 13C-NMR, FT-IR, TGA, SEM and elemental analysis, etc. The sulfonic acid group density and total density of all acid groups in the sulfonated carbonaceous material was determined by titration to be 1.24 mmol/g and 5.90 mmol/g, respectively. Its catalytic activity in the esterification of cyclohexanecarboxylic acid with anhydrous ethanol was shown to be comparable to that of the ionic exchange resin Amberlyst-15, when they were used in the same amount. In the meantime, the sulfonic acid group was found to be leached out by 26%–29% after it was exposed to hot water (95 °C for 5 h. The catalytic usefulness of the prepared carbonaceous material was investigated by performing esterifications.

  18. Springtime warming and reduced snow cover from carbonaceous particles

    Directory of Open Access Journals (Sweden)

    M. G. Flanner

    2009-04-01

    Full Text Available Boreal spring climate is uniquely susceptible to solar warming mechanisms because it has expansive snow cover and receives relatively strong insolation. Carbonaceous particles can influence snow coverage by warming the atmosphere, reducing surface-incident solar energy (dimming, and reducing snow reflectance after deposition (darkening. We apply a range of models and observations to explore impacts of these processes on springtime climate, drawing several conclusions: 1 Nearly all atmospheric particles (those with visible-band single-scatter albedo less than 0.999, including all mixtures of black carbon (BC and organic matter (OM, increase net solar heating of the atmosphere-snow column. 2 Darkening caused by small concentrations of particles within snow exceeds the loss of absorbed energy from concurrent dimming, thus increasing solar heating of snowpack as well (positive net surface forcing. Over global snow, we estimate 6-fold greater surface forcing from darkening than dimming, caused by BC+OM. 3 Equilibrium climate experiments suggest that fossil fuel and biofuel emissions of BC+OM induce 95% as much springtime snow cover loss over Eurasia as anthropogenic carbon dioxide, a consequence of strong snow-albedo feedback and large BC+OM emissions from Asia. 4 Of 22 climate models contributing to the IPCC Fourth Assessment Report, 21 underpredict the rapid warming (0.64°C decade−1 observed over springtime Eurasia since 1979. Darkening from natural and anthropogenic sources of BC and mineral dust exerts 3-fold greater forcing on springtime snow over Eurasia (3.9 W m−2 than North America (1.2 W m−2. Inclusion of this forcing significantly improves simulated continental warming trends, but does not reconcile the low bias in rate of Eurasian spring snow cover decline exhibited by all models, likely because BC deposition trends are negative or near-neutral over much of Eurasia. Improved Eurasian

  19. Laboratory Experiments on the Low-temperature Formation of Carbonaceous Grains in the ISM

    Science.gov (United States)

    Fulvio, Daniele; Góbi, Sándor; Jäger, Cornelia; Kereszturi, Ákos; Henning, Thomas

    2017-11-01

    The life cycle of cosmic dust grains is far from being understood and the origin and evolution of interstellar medium (ISM) grains is still under debate. In the ISM, the cosmic dust destruction rate is faster than the production rate by stellar sources. However, observations of ISM refractory matter suggest that to maintain a steady amount of cosmic grains, some supplementary production mechanism takes place. In this context, we aimed to study possible reformation mechanisms of cosmic grains taking place at low temperature directly in the ISM. The low-temperature condensation of carbonaceous materials has been investigated in experiments mimicking the ISM conditions. Gas-phase carbonaceous precursors created by laser ablation of graphite were forced to accrete on cold substrates (T ≈ 10 K) representing surviving dust grains. The growing and evolution of the condensing carbonaceous precursors have been monitored by MIR and UV spectroscopy under a number of experimental scenarios. For the first time, the possibility to form ISM carbonaceous grains in situ is demonstrated. The condensation process is governed by carbon chains that first condense into small carbon clusters and finally into more stable carbonaceous materials, of which structural characteristics are comparable to the material formed in gas-phase condensation experiments at very high temperature. We also show that the so-formed fullerene-like carbonaceous material is transformed into a more ordered material under VUV processing. The cold condensation mechanisms discussed here can give fundamental clues to fully understand the balance between the timescale for dust injection, destruction, and reformation in the ISM.

  20. The Oxygen Isotope Composition of Dark Inclusions in HEDs, Ordinary and Carbonaceous Chondrites

    Science.gov (United States)

    Greenwood, R. C.; Zolensky, M. E.; Buchanan, P. C.; Franchi, I. A.

    2015-01-01

    Dark inclusions (DIs) are lithic fragments that form a volumetrically small, but important, component in carbonaceous chondrites. Carbonaceous clasts similar to DIs are also found in some ordinary chondrites and HEDs. DIs are of particular interest because they provide a record of nebular and planetary processes distinct from that of their host meteorite. DIs may be representative of the material that delivered water and other volatiles to early Earth as a late veneer. Here we focus on the oxygen isotopic composition of DIs in a variety of settings with the aim of understanding their formational history and relationship to the enclosing host meteorite.

  1. Hierarchically structured carbonaceous foams generation and their use as electrochemical energy storage devices

    Energy Technology Data Exchange (ETDEWEB)

    Brun, Nicolas [Centre de Recherche Paul Pascal, Pessac (France); Institut des Sciences Moleculaires, Talence (France); Prabaharan, Savari R.S.; Morcrette, Mathieu [Laboratoire de Reactivite et de Chimie des Solides, Amiens (France); Pecastaing, Gilles [Laboratoire de Chimie des Polymeres Organiques, Pessac (France); Birot, Marc; Deleuze, Herve [Institut des Sciences Moleculaires, Talence (France); Backov, Renal [Centre de Recherche Paul Pascal, Pessac (France)

    2010-07-01

    Hierarchically structured carbonaceous foams with a high control over macro-meso-microporous structures have been synthesized, using silica as inorganic exotemplate and phenolic resin as carbon precursor. These monolithic foams have been thoroughly characterized over all length scales. The applications of this new series of macrocellular carbonaceous monoliths as negative electrodes for Lithium-ion batteries devices (stable capacity of 200 mAh.g{sup -1}, during 50 cycles) and electrochemical capacitors (specific capacitance of 30 F.g{sup -1} at a scan rate of 10 mV.s{sup -1}) have been checked and will be discussed. (orig.)

  2. Simulation of cometary infrared spectra using laboratory extinction data of carbonaceous materials

    Energy Technology Data Exchange (ETDEWEB)

    Colangeli, L.; Bussoletti, E.; Papoular, R.; Mennella, V. (Cassino Universita (Italy) Istituto Universitario Navale, Naples (Italy) CEA, Centre d' Etudes Nucleaires de Saclay, Gif-sur-Yvette (France) Osservatorio Astronomico di Capodimonte, Naples (Italy))

    1990-07-01

    Laboratory observations of the behavior of hydrogenated amorphous carbon (HAC) and the vitreous homogeneous organic compound vitrine may furnish a key to the identification of the 3.3-3.4 micron bands encountered in Comet Halley spectra between 3 and 4 microns. When the HAC annealing temperature rises, or when the rank of vitrines increases, a similar change occurs in the structure of these carbonaceous materials from a prevalent aliphatic to a dominant aromatic character. In situ mass spectrometry investigations of CHON particles conducted by Giotto and both Vega 1 and 2 appear to confirm the similarity of physical structure between carbonaceous particles and those observed in the laboratory. 46 refs.

  3. Static Code Analysis with Gitlab-CI

    CERN Document Server

    Datko, Szymon Tomasz

    2016-01-01

    Static Code Analysis is a simple but efficient way to ensure that application’s source code is free from known flaws and security vulnerabilities. Although such analysis tools are often coming with more advanced code editors, there are a lot of people who prefer less complicated environments. The easiest solution would involve education – where to get and how to use the aforementioned tools. However, counting on the manual usage of such tools still does not guarantee their actual usage. On the other hand, reducing the required effort, according to the idea “setup once, use anytime without sweat” seems like a more promising approach. In this paper, the approach to automate code scanning, within the existing CERN’s Gitlab installation, is described. For realization of that project, the Gitlab-CI service (the “CI” stands for "Continuous Integration"), with Docker assistance, was employed to provide a variety of static code analysers for different programming languages. This document covers the gene...

  4. Filosofia da ciência e ensino da ciência: uma analogia

    Directory of Open Access Journals (Sweden)

    Alberto Villani

    2001-01-01

    Full Text Available Neste trabalho, inicialmente explicitaremos nossa compreensão do debate entre Kuhn, Popper, Lakatos e Feyerabend na Conferencia Internacional sobre Filosofia da Ciência (1965, delineando as diferenças nas posições de nossos filósofos. Em seguida apresentaremos um quadro das posições sobre o ensino de ciências, assim como nos parecem caracterizar os último 30 anos de pesquisas na área. Finalmente tentaremos uma aproximação dos dois campos, procurando salientar as implicações que a problemática filosófica teve e tem para uma maior compreensão do ensino de ciências e matemática.

  5. The analysis of creep characteristics of the surrounding rock of the carbonaceous rock tunnel based on Singh-Mitchell model

    Science.gov (United States)

    Luo, Junhui; Mi, Decai; Ye, Qiongyao; Deng, Shengqiang; Zeng, Fuquan; Zeng, Yongjun

    2018-01-01

    Carbonaceous rock has the characteristics of easy disintegration, softening, swelling and environmental sensitivity, which belongs to soft surrounding rock, and the deformation during excavation and long-term stability of the surrounding rock of carbonaceous rock tunnel are common problems in the construction of carbonaceous rock tunnel. According to the above, the Monitor and measure the displacement, temperature and osmotic pressure of the surrounding carbonaceous rock of the tunnel of Guangxi Hebai highway. Then it based on the obtaining data to study the creep mechanism of surrounding rock using Singh-Mitchell model and predict the deformation of surrounding rock before the tunnel is operation. The results show that the Singh-Mitchell creep model can effectively analyse and predict the deformation development law of surrounding rock of tunnel without considering temperature and osmotic pressure, it can provide reference for the construction of carbonaceous rock tunnel and the measures to prevent and reinforce it..

  6. Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols

    Directory of Open Access Journals (Sweden)

    M. O. Andreae

    2006-01-01

    Full Text Available Although the definition and measurement techniques for atmospheric 'black carbon' ('BC' or 'elemental carbon'' ('EC' have long been subjects of scientific controversy, the recent discovery of light-absorbing carbon that is not black ('brown carbon, Cbrown' makes it imperative to reassess and redefine the components that make up light-absorbing carbonaceous matter (LAC in the atmosphere. Evidence for the atmospheric presence of Cbrown comes from (1 spectral aerosol light absorption measurements near specific combustion sources, (2 observations of spectral properties of water extracts of continental aerosol, (3 laboratory studies indicating the formation of light-absorbing organic matter in the atmosphere, and (4 indirectly from the chemical analogy of aerosol species to colored natural humic substances. We show that brown carbon may severely bias measurements of 'BC' and 'EC' over vast parts of the troposphere, especially those strongly polluted by biomass burning, where the mass concentration of Cbrown is high relative to that of soot carbon. Chemical measurements to determine 'EC' are biased by the refractory nature of Cbrown as well as by complex matrix interferences. Optical measurements of 'BC' suffer from a number of problems: (1 many of the presently used instruments introduce a substantial bias into the determination of aerosol light absorption, (2 there is no unique conversion factor between light absorption and 'EC' or 'BC' concentration in ambient aerosols, and (3 the difference in spectral properties between the different types of LAC, as well as the chemical complexity of Cbrown, lead to several conceptual as well as practical complications. We also suggest that due to the sharply increasing absorption of Cbrown towards the UV, single-wavelength light absorption measurements may not be adequate for the assessment of absorption of solar radiation in the troposphere. We discuss the possible consequences of these effects for our

  7. Elites acadêmicas: as ciências sociais na Academia Brasileira de Ciências

    Directory of Open Access Journals (Sweden)

    Ana Paula Hey

    Full Text Available Resumo O objetivo do artigo consiste em evidenciar certo padrão de carreira científica dos trinta membros da seção de ciências sociais da centenária Academia Brasileira de Ciências. Criada em 2000, a área é composta por antropologia, demografia, ciência política, economia, geografia, história, relações internacionais e sociologia, disciplinas que materializam hierarquias e diferenciações. Os Acadêmicos são caracterizados por uma série de elementos: origem geográfica, gênero, idade e formação científica. Evidencia-se que os percursos de formação do capital científico e de notoriedade mesclam-se ao da construção das instituições e dos suportes que viabilizaram a institucionalização dessas ciências entre os anos de 1960 e 1980. As elites acadêmicas ora construídas evidenciam um modo de consagração que tem como princípio a condução do reconhecimento seletivo dos pares. Essa ação simbólica revela os traços das condições sociais de possibilidade da vida acadêmica no país.

  8. Successive self-propagating sintering process using carbonaceous materials: A novel low-cost remediation approach for dioxin-contaminated solids

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Long, E-mail: zhaolong@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Dayangfang 8, Beijing 100012 (China); Hou, Hong, E-mail: houhong@craes.org.cn [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Dayangfang 8, Beijing 100012 (China); Zhu, Tengfei; Li, Fasheng [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Dayangfang 8, Beijing 100012 (China); Terada, Akihiko; Hosomi, Masaaki [Department of Chemical Engineering, Faculty of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588 (Japan)

    2015-12-15

    Highlights: • A SSPSP using carbonaceous materials for removing dioxin pollutants was developed. • Removal and degradation efficiencies of DL-PCBs were higher than those of PCDD/Fs. • Compositions of PCDD/Fs were dependent on the available precursors in raw materials. • Dechlorination of O{sub 8}CDD and formation pathways of PCDFs were deduced. • Dioxin levels in the effluent gas complied with the International emission limit. - Abstract: The disposal of dioxin-contaminated solids was studied using a novel successive self-propagating sintering process (SSPSP) incorporating a carbonaceous material. Among the five types of carbonaceous materials investigated, Charcoal B displayed optimum adsorbent properties and was selected as the best thermal source in the current remediation approach based on economical efficiency aspects. The feasibility of this proposed approach, removal efficiencies, and congener compositions of dioxins were examined using two types of dioxin-contaminated solids (Fugan sediment and Toyo soil) that displayed different characteristics including the initial concentrations of dioxins. The removal efficiencies of DL-PCBs (“dioxin-like” polychlorinated biphenyls) were higher than those of PCDD/Fs (polychlorinated dibenzo-p-dioxins/dibenzofurans), achieving 99.9 and 92% removal in the Fugan sediment and Toyo soil, respectively. In contrast, the degradation efficiencies of DL-PCBs were lower (i.e., 89.3 and 88.8%, respectively). The initial concentrations of dioxins, available precursors, and properties of the solids strongly influenced the congener compositions and removal efficiencies of dioxins. Furthermore, the dechlorination reaction pathways of high-chlorinated PCDDs and potential regeneration pathways of PCDFs from PCBs were deduced using isotope labeling. The proposed novel low-cost remediation approach for the removal of dioxins from solids is a highly efficient and environmentally sound treatment technology.

  9. Direct Carbon Fuel Cell System Utilizing Solid Carbonaceous Fuels

    Energy Technology Data Exchange (ETDEWEB)

    Turgut Gur

    2010-04-30

    This 1-year project has achieved most of its objective and successfully demonstrated the viability of the fluidized bed direct carbon fuel cell (FB-DCFC) approach under development by Direct Carbon technologies, LLC, that utilizes solid carbonaceous fuels for power generation. This unique electrochemical technology offers high conversion efficiencies, produces proportionately less CO{sub 2} in capture-ready form, and does not consume or require water for gasification. FB-DCFC employs a specialized solid oxide fuel cell (SOFC) arrangement coupled to a Boudouard gasifier where the solid fuel particles are fluidized and reacted by the anode recycle gas CO{sub 2}. The resulting CO is electrochemically oxidized at the anode. Anode supported SOFC structures employed a porous Ni cermet anode layer, a dense yttria stabilized zirconia membrane, and a mixed conducting porous perovskite cathode film. Several kinds of untreated solid fuels (carbon and coal) were tested in bench scale FBDCFC prototypes for electrochemical performance and stability testing. Single cells of tubular geometry with active areas up to 24 cm{sup 2} were fabricated. The cells achieved high power densities up to 450 mW/cm{sup 2} at 850 C using a low sulfur Alaska coal char. This represents the highest power density reported in the open literature for coal based DCFC. Similarly, power densities up to 175 mW/cm{sup 2} at 850 C were demonstrated with carbon. Electrical conversion efficiencies for coal char were experimentally determined to be 48%. Long-term stability of cell performance was measured under galvanostatic conditions for 375 hours in CO with no degradation whatsoever, indicating that carbon deposition (or coking) does not pose any problems. Similar cell stability results were obtained in coal char tested for 24 hours under galvanostatic conditions with no sign of sulfur poisoning. Moreover, a 50-cell planar stack targeted for 1 kW output was fabricated and tested in 95% CO (balance CO{sub 2

  10. Petrography of the carbonaceous, diamond-bearing stone "Hypatia" from southwest Egypt: A contribution to the debate on its origin

    Science.gov (United States)

    Belyanin, Georgy A.; Kramers, Jan D.; Andreoli, Marco A. G.; Greco, Francesco; Gucsik, Arnold; Makhubela, Tebogo V.; Przybylowicz, Wojciech J.; Wiedenbeck, Michael

    2018-02-01

    The stone named "Hypatia" found in the Libyan Desert Glass area of southwest Egypt is carbon-dominated and rich in microdiamonds. Previous noble gas and nitrogen isotope studies suggest an extraterrestrial origin. We report on a reconnaissance study of the carbonaceous matrix of this stone and the phases enclosed in it. This focused on areas not affected by numerous transecting fractures mostly filled with secondary minerals. The work employed scanning electron microscopy (SEM) with energy-dispersive (EDS) and wavelength-dispersive (WDS) electron microprobe (EMPA) analysis, Proton Induced X-ray Emission (PIXE) spectrometry and micro-Raman spectroscopy. We found that carbonaceous matrices of two types occur irregularly intermingled on the 50-500 μm scale: Matrix-1, consisting of almost pure carbonaceous matter, and Matrix-2, containing Fe, Ni, P and S at abundances analyzable by microprobe. Matrix-2 contains the following phases as inclusions: (i) (Fe,Ni) sulphide occurring in cloud-like concentrations of sub-μm grains, in domains of the matrix that are enriched in Fe and S. These domains have (Fe + Ni)/S (atomic) = 1.51 ± 0.24 and Ni/Fe = 0.086 ± 0.061 (both 1SD); (ii) grains up to ∼5 μm in size of moissanite (SiC); (iii) Ni-phosphide compound grains up to 60 μm across that appear cryptocrystalline or amorphous and have (Ni + Fe)/P (atomic) = 5.6. ± 1.7 and Ni/Fe = 74 ± 29 (both 1SD), where both these ratios are much higher than any known Ni-phosphide minerals; (iv) rare grains (observed only once) of graphite, metallic Al, Fe and Ag, and a phase consisting of Ag, P and I. In Matrix-2, Raman spectroscopy shows a prominent narrow diamond band at 1340 cm-1. In Matrix-1 the D and G bands of disordered carbon are dominant, but a minor diamond band is ubiquitous, accounting for the uniform hardness of the material. The D and G bands have average full width at half maximum (FWHM) values of 295 ± 19 and 115 ± 19 cm-1, respectively, and the D/G intensity ratio

  11. Preparation and evaluation of magnetic carbonaceous materials for pesticide and metal removal.

    Science.gov (United States)

    Ohno, Masaki; Hayashi, Hiroki; Suzuki, Kazuyuki; Kose, Tomohiro; Asada, Takashi; Kawata, Kuniaki

    2011-07-15

    Magnetic carbonaceous materials were produced by carbonization of a cation exchange resin loaded with ferrous or ferric iron and activation using sieved oyster shell as the activation agent. The magnetic carbonaceous material with the maximum magnetic flux density on every axis (ESS-1) was obtained from the ferric-loaded resin by carbonization at 700°C, followed by activation with the oyster shell at 900°C, and magnetization. A separate step of carbonization and activation appears to cause more of a reduction reaction of Fe to form γ-Fe(2)O(3). The Fe compound in the magnetic carbonaceous material was identified from the XRD pattern as mainly γ-Fe(2)O(3). The magnetic flux density on every axis increased linearly as the amount of the oyster shell increased. Moreover, the adsorption ability of the products was evaluated for pesticides and metal ions. Both ESS-1 and a carbonaceous material obtained from the resin without ferric ion (RC) appear to have the highest adsorption ability for lead. Furthermore, the adsorption ability of ESS-1 might decrease by blockages of the pores with the loaded Fe compounds. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Gasoline cars produce more carbonaceous particulate matter than modern filter-equipped diesel cars.

    Science.gov (United States)

    Platt, S M; El Haddad, I; Pieber, S M; Zardini, A A; Suarez-Bertoa, R; Clairotte, M; Daellenbach, K R; Huang, R-J; Slowik, J G; Hellebust, S; Temime-Roussel, B; Marchand, N; de Gouw, J; Jimenez, J L; Hayes, P L; Robinson, A L; Baltensperger, U; Astorga, C; Prévôt, A S H

    2017-07-13

    Carbonaceous particulate matter (PM), comprising black carbon (BC), primary organic aerosol (POA) and secondary organic aerosol (SOA, from atmospheric aging of precursors), is a highly toxic vehicle exhaust component. Therefore, understanding vehicle pollution requires knowledge of both primary emissions, and how these emissions age in the atmosphere. We provide a systematic examination of carbonaceous PM emissions and parameterisation of SOA formation from modern diesel and gasoline cars at different temperatures (22, -7 °C) during controlled laboratory experiments. Carbonaceous PM emission and SOA formation is markedly higher from gasoline than diesel particle filter (DPF) and catalyst-equipped diesel cars, more so at -7 °C, contrasting with nitrogen oxides (NO X ). Higher SOA formation from gasoline cars and primary emission reductions for diesels implies gasoline cars will increasingly dominate vehicular total carbonaceous PM, though older non-DPF-equipped diesels will continue to dominate the primary fraction for some time. Supported by state-of-the-art source apportionment of ambient fossil fuel derived PM, our results show that whether gasoline or diesel cars are more polluting depends on the pollutant in question, i.e. that diesel cars are not necessarily worse polluters than gasoline cars.

  13. Carbonaceous material in fine particulate matter (PM10) of urban areas

    International Nuclear Information System (INIS)

    Brocco, Domenico; Leonardi, Vittorio; Maso; Marco; Prignani, Patrizia

    2006-01-01

    Total carbon (TC), elemental carbon (EC) and organic carbon (OC) in the fine particulate matter (PM10) were measured in the urban areas of Rome and Marino (Castelli Romani) by means a thermal method with a non-dispersive infrared detector (NDIR). The results showed that carbonaceous material constitutes 30-40% of the total aerosols in Rome and about 20% in Marino [it

  14. Carbonaceous Aerosols in Fine Particulate Matter of Santiago Metropolitan Area, Chile

    Science.gov (United States)

    Toro Araya, Richard; Flocchini, Robert; Morales Segura, Rául G. E.; Leiva Guzmán, Manuel A.

    2014-01-01

    Measurements of carbonaceous aerosols in South American cities are limited, and most existing data are of short term and limited to only a few locations. For 6 years (2002–2007), concentrations of fine particulate matter and organic and elemental carbon were measured continuously in the capital of Chile. The contribution of carbonaceous aerosols to the primary and secondary fractions was estimated at three different sampling sites and in the warm and cool seasons. The results demonstrate that there are significant differences in the levels in both the cold (March to August) and warm (September to February) seasons at all sites studied. The percent contribution of total carbonaceous aerosol fine particulate matter was greater in the cool season (53 ± 41%) than in the warm season (44 ± 18%). On average, the secondary organic carbon in the city corresponded to 29% of the total organic carbon. In cold periods, this proportion may reach an average of 38%. A comparison of the results with the air quality standards for fine particulate matter indicates that the total carbonaceous fraction alone exceeds the World Health Organization standard (10 µg/m3) and the United States Environmental Protection Agency standard (15 µg/m3) for fine particulate matter. PMID:24587753

  15. Impact of anthropogenic emissions and open biomass burning on regional carbonaceous aerosols in South China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Gan, E-mail: zhanggan@gig.ac.c [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li Jun [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Li Xiangdong [Department of Civil and Structural Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Xu Yue; Guo Lingli [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Tang Jianhui [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China); Lee, Celine S.L. [Department of Civil and Structural Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Liu Xiang [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Chen Yingjun [Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003 (China)

    2010-11-15

    Carbonaceous aerosols were studied at three background sites in south and southwest China. Hok Tsui in Hong Kong had the highest concentrations of carbonaceous aerosols (OC = 8.7 {+-} 4.5 {mu}g/m{sup 3}, EC = 2.5 {+-} 1.9 {mu}g/m{sup 3}) among the three sites, and Jianfeng Mountains in Hainan Island (OC = 5.8 {+-} 2.6 {mu}g/m{sup 3}, EC = 0.8 {+-} 0.4 {mu}g/m{sup 3}) and Tengchong mountain over the east edge of the Tibetan Plateau (OC = 4.8 {+-} 4.0 {mu}g/m{sup 3}, EC = 0.5 {+-} 0.4 {mu}g/m{sup 3}) showed similar concentration levels. Distinct seasonal patterns with higher concentrations during the winter, and lower concentrations during the summertime were observed, which may be caused by the changes of the regional emissions, and monsoon effects. The industrial and vehicular emissions in East, Southeast and South China, and the regional open biomass burning in the Indo-Myanmar region of Asia were probably the two major potential sources for carbonaceous matters in this region. - Anthropogenic emissions in China and open biomass burning in the Indo-Myanmar region were the two major potential sources for carbonaceous matters in South China region.

  16. Isotropic and high density carbon made from carbonaceous powder prepared by distillation under reduced pressure

    International Nuclear Information System (INIS)

    Mukohara, Susumu; Suzuki, Hiroshige

    1978-01-01

    It is attempted to produce high density, high strength and isotropic carbon made from carbonaceous powder. The carbonaceous powder was prepared by carbonization of coal-tar pitch at a temperature of 440 - 500 0 C and subsequent distillation under reduced pressure. The distillation was performed at a temperature of 300 - 500 0 C below the carbonization temperature. In some cases additional quinoline extraction was carried out on the powder. Green carbon body was formed without binder pitch under isostatic pressure at room temperature. The body was heat-treated at a temperature of 1100 - 2800 0 C. Bulk density, weight loss, shrinkage, strength, lattice parameter, crystallite size and BAF of the obtained carbon body were measured. It is confirmed that high density, high strength and isotropic carbon made from the carbonaceous powder and the following results were obtained. 1) BS (benzene soluble) fraction, β-resin (benzene insoluble and quinoline soluble) fraction and QI (quinoline insoluble) fraction were able to fractionate by distillation under reduced pressure. Concentration gradient of each fraction seems to exist in the carbonaceous powder. 2) Using the powder prepared by a lower temperature of the carbonization and/or the distillation, the carbon body had higher bulk density and higher strength. 3) The β-resin fraction had the effects of increasing the green density and enhancing the shrinkage of carbon body during the heat treatment. (author)

  17. Carbonaceous Aerosol Characteristics over a Pinus taeda plantation: Results from the CELTIC experiment

    Science.gov (United States)

    Carbonaceous particles smaller than 2.5 um aerodynamic diameter (PM2.5) were collected in July, 2003 over a Loblolly Pine plantation at Duke Forest, NC during the Chemical Emission, Loss, Transformation and Interactions within Canopies (CELTIC) field study. Organic (OC) and eleme...

  18. R Raman Spectroscopy and Petrology of Antarctic CR Chondrites: Comparison with Other Carbonaceous Chondrites

    Science.gov (United States)

    Komatsu, M.; Fagan, T. J.; Yamaguchi, A.; Mikouchi, T.; Zolensky, M. E.; Yasutake, M.

    2015-01-01

    In Renazzo-like carbonaceous (CR) chondrites, abundant original Fe,Ni-metal is preserved in chrondules, but the matrix is characterized by fine-grained magnetite with phyllosilicate. This combination of reduced Fe in chrodrules with oxidized Fe and phyllosilicate in the matrix has been attributed to aqueous alteration of matrix at relatively low temperatures.

  19. Effects of chemical functional groups on elemental mercury adsorption on carbonaceous surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jing, E-mail: liujing27@mail.hust.edu.cn [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Cheney, Marcos A. [Department of Natural Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853 (United States); Wu Fan; Li Meng [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-02-15

    A systematic theoretical study using density functional theory is performed to provide molecular-level understanding of the effects of chemical functional groups on mercury adsorption on carbonaceous surfaces. The zigzag and armchair edges were used in modeling the carbonaceous surfaces to simulate different adsorption sites. The edge atoms on the upper side of the models are unsaturated to simulate active sites. All calculations (optimizations, energies, and frequencies) were made at B3PW91 density functional theory level, using RCEP60VDZ basis set for mercury and 6-31G(d) pople basis set for other atoms. The results indicate that the embedding of halogen atom can increase the activity of its neighboring site which in turn increases the adsorption capacity of the carbonaceous surface for Hg{sup 0}. The adsorption belongs to chemisorptions, which is in good agreement with the experimental results. For the effects of oxygen functional groups, lactone, carbonyl and semiquinone favor Hg{sup 0} adsorption because they increase the neighboring site's activity for mercury adsorption. On the contrary, phenol and carboxyl functional groups show a physisorption of Hg{sup 0}, and reduce Hg capture. This result can explain the seemingly conflicting experimental results reported in the literature concerning the influence of oxygen functional groups on mercury adsorption on carbonaceous surface.

  20. Composition and sources of carbonaceous aerosols in Northern Europe during winter

    NARCIS (Netherlands)

    Glasius, M.; Hansen, A.M.K.; Claeys, M.; Henzing, J.S.; Jedynska, A.D.; Kasper-Giebl, A.; Kistler, M.; Kristensen, K.; Martinsson, J.; Maenhaut, W.; Nøjgaard, J.K.; Spindler, G.; Stenström, K.E.; Swietlicki, E.; Szidat, S.; Simpson, D.; Yttri, K.E.

    2018-01-01

    Sources of elemental carbon (EC) and organic carbon (OC) in atmospheric aerosols (carbonaceous aerosols) were investigated by collection of weekly aerosol filter samples at six background sites in Northern Europe (Birkenes, Norway; Vavihill, Sweden; Risoe, Denmark; Cabauw and Rotterdam in The

  1. The application of a layer of carbonaceous material to a surface

    International Nuclear Information System (INIS)

    Holland, L.A.

    1981-01-01

    A method of applying a carbonaceous material to a surface is described. It consists of exposing the surface to an ionised gas atmosphere generated in a gas consisting substantially of carbon and hydrogen, and applying to the surface through capacitive means an electrical potential which changes in sign at time intervals of between 5 x 10 -9 seconds and 10 -6 seconds. (author)

  2. Sorption of ionizable and ionic organic compounds to biochar, activated carbon and other carbonaceous materials.

    Science.gov (United States)

    Kah, Melanie; Sigmund, Gabriel; Xiao, Feng; Hofmann, Thilo

    2017-11-01

    The sorption of ionic and ionizable organic compounds (IOCs) (e.g., pharmaceuticals and pesticides) on carbonaceous materials plays an important role in governing the fate, transport and bioavailability of IOCs. The paradigms previously established for the sorption of neutral organic compounds do not always apply to IOCs and the importance of accounting for the particular sorption behavior of IOCs is being increasingly recognized. This review presents the current state of knowledge and summarizes the recent advances on the sorption of IOCs to carbonaceous sorbents. A broad range of sorbents were considered to evaluate the possibility to read across between fields of research that are often considered in isolation (e.g., carbon nanotubes, graphene, biochar, and activated carbon). Mechanisms relevant to IOCs sorption on carbonaceous sorbents are discussed and critically evaluated, with special attention being given to emerging sorption mechanisms including low-barrier, charge-assisted hydrogen bonds and cation-π assisted π-π interactions. The key role played by some environmental factors is also discussed, with a particular focus on pH and ionic strength. Overall the review reveals significant advances in our understanding of the interactions between IOCs and carbonaceous sorbents. In addition, knowledge gaps are identified and priorities for future research are suggested. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Structure characteristics and combustibility of carbonaceous materials from blast furnace flue dust

    International Nuclear Information System (INIS)

    Zhao, Di; Zhang, Jianliang; Wang, Guangwei; Conejo, Alberto N.; Xu, Runsheng; Wang, Haiyang; Zhong, Jianbo

    2016-01-01

    Highlights: • The combustion properties of carbonaceous materials in dust were investigated. • The mico-structures of carbon materials in dusts were exemplified distinctly. • The carbon activity differences were depended on their diverse mico-structures. • Kinetic parameters were obtained in the method of nonlinear least-squares fitting. • VM and RPM model for carbonaceous materials in dust and their pyrolytic coke. - Abstract: The structure characteristics and combustibility of carbonaceous materials from gravitational dust and bag dust of hop pocket were investigated using laser particle size analyzer, scanning electron microscopy, X-ray Diffraction, polarization microscopy and thermogravimetric analysis. Simultaneously, coal char and pyrolyzed coke were used as comparison. The acid-washing process was performed to avoid the effects of inorganic matters and beneficiate carbonaceous materials in dust. Three representative gas-solid reactivity models, random pore model, volume model, and unreacted core model were applied to study kinetic parameters. Results showed that carbonaceous materials in dust were mainly originated from coke fines and those in bag dust of hop pocket presented a high reactivity, mainly attributed to its more disordered crystalline structure and higher porosity. It was concluded from kinetic analysis that volume model was the best model for simulating the combustion process. The activation energies of bag dust of hop pocket, gravitational dust and coke calculated by this model were 118.6 kJ/mol, 141.7 kJ/mol, 156.1 kJ/mol, respectively, indicating carbon in bag dust of hop pocket are easily reacted with oxygen and proving its high combustibility.

  4. Spectro-Microscopic Measurements of Carbonaceous Aerosol Aging in Central California

    Energy Technology Data Exchange (ETDEWEB)

    Moffet, Ryan C.; Rodel, Tobias; Kelly, Stephen T.; Yu, Xiao-Ying; Carroll, Gregory; Fast, Jerome D.; Zaveri, Rahul A.; Laskin, Alexander; Gilles, Mary K.

    2013-10-29

    Carbonaceous aerosols are responsible for large uncertainties in climate models, degraded visibility, and adverse health effects. The Carbonaceous Aerosols and Radiative Effects Study (CARES) was designed to study carbonaceous aerosols in the natural environment of Central Valley, California, and learn more about their atmospheric formation and aging. This paper presents results from spectro-microscopic measurements of carbonaceous particles collected during CARES at the time of pollution accumulation event (June 27-29, 2010), when in situ measurements indicated an increase in the organic carbon content of aerosols as the Sacramento urban plume aged. Computer controlled scanning electron microscopy coupled with an energy dispersive X-ray detector (CCSEM/EDX) and scanning transmission X-ray microscopy coupled with near edge X-ray absorption spectroscopy (STXM/NEXAFS) were used to probe the chemical composition and morphology of individual particles. It was found that the mass of organic carbon on individual particles increased through condensation of secondary organic aerosol. STXM/NEXAFS indicated that the number fraction of homogenous organic particles lacking inorganic inclusions (greater than ~50 nm diameter) increased with plume age as did the organic mass per particle. Comparison of the CARES spectro-microscopic data set with a similar dataset obtained in Mexico City during the MILAGRO campaign showed that individual particles in Mexico City contained twice as much carbon as those sampled during CARES. The number fraction of soot particles at the Mexico City urban site (30%) was larger than at the CARES urban site (10%) and the most aged samples from CARES contained less carbon-carbon double bonds. Differences between carbonaceous particles in Mexico City and California result from different sources, photochemical conditions, gas phase reactants, and secondary organic aerosol precursors. The detailed results provided by these spectro-microscopic measurements

  5. O homem e as ciências da natureza

    OpenAIRE

    Archer, Luís

    1985-01-01

    1. Introdução 2. Como homem e ciências da natureza entram em confronto 3. O homem que se projecta nas ciências da natureza 4. As ciências da natureza que se projectam no homem 5. Homem e ciências da natureza em interprojecção: o futuro

  6. Characterization of carbonaceous matter in xenolithic clasts from the Sharps (H3.4) meteorite: Constraints on the origin and thermal processing

    Energy Technology Data Exchange (ETDEWEB)

    Kebukawa, Yoko [Yokohama National Univ. (Japan); Zolensky, Michael E. [NASA Johnson Space Center, Houston, TX (United States); Chan, Queenie H. S. [NASA Johnson Space Center, Houston, TX (United States); Nagao, Keisuke [Univ. of Tokyo (Japan); Kilcoyne, A. L. David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bodnar, Robert J. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Farley, Charles [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Rahman, Zia [NASA Johnson Space Center, Houston, TX (United States); Le, Loan [NASA Johnson Space Center, Houston, TX (United States); Cody, George D. [Carnegie Inst. of Washington, Washington, DC (United States)

    2016-09-25

    Primitive xenolithic clasts, often referred to as “dark clasts”, are well known in many regolith breccias. The Sharps H3.4 ordinary chondrite contains unusually large dark clasts up to ~1 cm across. Poorly-graphitized carbon (PGC), with Fe, Ni metal and described as “carbon-rich aggregates”, has been found in these clasts (Brearley, 1990). We report detailed analyses of carbonaceous matter in several identical Sharps clasts using FTIR, Raman, C-XANES, and TEM that provide insight on the extent of thermal processing and possible origin of such clasts. We also prepared acid residues of the clasts using the HCl/HF method and conducted mass spectrometric analysis of the entrained noble gases. Carbonaceous matter is often used to infer thermal history due to its sensitivity to thermal processes. The FTIR spectra of the acid residue from the Sharps clast suggest that carbonaceous matter in the clast contains less hydrogen and oxygen compared to acid residues from typical type 3.4 ordinary chondrites. The metamorphic temperatures obtained by Raman spectroscopy ranges between ~380 °C and ~490 °C. TEM observations indicate that the clasts experienced a peak temperature of 300 °C to 400 °C, based on the carbon d 002 layer lattice spacing of C-rich aggregates. These estimates are consistent with an earlier estimate of 330 ± 50 °C, that is also estimated by the d 002 layer lattice spacing (Brearley, 1990). It should be noted that the lattice spacing thermometer is based on terrestrial metamorphose rocks, and thus temperature was probably underestimated. Meanwhile, the C-XANES spectra of the C-rich aggregates show high exciton intensities, indicative of graphene structures that developed at around 700–800 °C following an extensive period of time (millions of years), however, the surrounding matrix areas experienced lower temperatures of less than 300–500 °C. Noble gas analysis of the acid residue from the Sharps clasts shows that the residue is

  7. In-Situ Oxygen Isotopic Composition of Tagish Lake: An Ungrouped Type 2 Carbonaceous Chondrite

    Science.gov (United States)

    Zolensky, Michael E.; Engrand, Cecile; Gounelle, Matthieu; Zolensky, Mike E.

    2001-01-01

    We have measured the oxygen isotopic composition of several components of Tagish Lake by ion microprobe. This meteorite constitutes the best preserved sample of C2 matter presently available for study. It presents two different lithologies (carbonate-poor and -rich) which have fairly comparable oxygen isotopic composition, with regard to both the primary or secondary minerals. For the olivine and pyroxene grains, their delta O-18 values range from - 10.5% to + 7.4% in the carbonate-poor lithology, with a mean Delta O-17 value of - 3.7 2.4%. In the carbonate-rich lithology, delta O-18 varies from - 7.9% to + 3.3%, and the mean Delta O-17 value is - 4.7 +/- 1.4%. Olivine inclusions (Fo(sub >99)) with extreme O-16-enrichment were found in both lithologies: delta O-18 = - 46.1 %, delta O-187= - 48.3% and delta O-18 = - 40.6%, delta O-17 = - 41.2% in the carbonate-rich lithology; delta O-18 = - 41.5%, delta O-17 = -43.4%0 in the carbonate-poor lithology. Anhydrous minerals in the carbonate-poor lithology are slightly more O-16-rich than in the carbonate-rich one. Four low-iron manganese-rich (LIME) olivine grains do not have an oxygen isotopic composition distinct from the other "normal" olivines. The phyllosilicate matrix presents the same range of oxygen isotopic compositions in both lithologies: delta O-18 from approximately 11 % to approximately 6%, with an average Delta. O-17 approximately 0%. Because the bulk Tagish Lake oxygen isotopic composition given by Brown et al. is on the high end of our matrix analyses, we assume that this "bulk Tagish Lake" composition probably only represents that of the carbonate-rich lithology. Calcium carbonates have delta O-18 values up to 35%, with Delta O-17 approximately 0.5%0. Magnetite grains present very high Delta O-17 values approximately + 3.4%0 +/- 1.2%. Given our analytical uncertainties and our limited carbonate data, the matrix and the carbonate seem to have formed in isotopic equilibrium. In that case, their large isotopic fractionation would argue for a low temperature (CM-like, T approximately 0 deg) formation. Magnetite probably formed during a separate event. Tagish Lake magnetite data is surprisingly compatible with that of R-chondrites and unequilibrated ordinary (LL3) chondrites. Our oxygen isotope data strongly supports the hypothesis of a single precursor for both lithologies. Drastic mineralogical changes between the two lithologies not being accompanied with isotopic fractionation seem compatible with the alteration model presented by Young et aI. Tagish Lake probably represents the first well preserved large sample of the C2 matter that dominates interplanetary matter since the formation of the solar system.

  8. The Biological Potency Of Carbonaceous Nanoparticles Is Associated With The State Of Oxidation Of Surface Carbon Atoms

    Science.gov (United States)

    Epidemiological studies have shown that exposure to ambient particulate matter (PM) is associated with excess morbidity and mortality. An important component of PM consists of inorganic and organic compounds adsorbed onto a carbonaceous particle core. Toxicological studies indica...

  9. A European Aerosol Phenomenology -4: Harmonized Concentrations of Carbonaceous Aerosol at 10 Regional Background Sites Across Europe.

    Czech Academy of Sciences Publication Activity Database

    Cavalli, F.; Areskoug, H.; Ceburnis, D.; Čech, J.; Genberg, J.; Harrison, R.M.; Jaffrezo, J.L.; Kiss, G.; Laj, P.; Mihalopoulos, N.; Perez, N.; Quincey, P.; Schwarz, Jaroslav; Sellegri, K.; Spindler, G.; Swietlicki, E.; Theodosi, C.; Yttri, K.E.; Aas, W.; Putaud, J.P.

    2016-01-01

    Roč. 144, NOV 2016 (2016), s. 133-145 ISSN 1352-2310 Institutional support: RVO:67985858 Keywords : aerosol * carbonaceous * PM Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.629, year: 2016

  10. NWA 1152 and Sahara 00182: New primitive carbonaceous chondrites with affinities to the CR and CV groups

    Science.gov (United States)

    Smith, Caroline L.; Russell, Sara S.; Gounelle, Matthieu; Greenwood, Richard C.; Franchi, Ian A.

    2004-12-01

    We have investigated the mineralogy, petrography, bulk chemistry, and light element isotope composition of the ungrouped chondrites North West Africa (NWA) 1152 and Sahara 00182. NWA 1152 contains predominantly type 1 porphyritic olivine (PO) and porphyritic olivine-pyroxene (POP) chondrules. Chondrule silicates are magnesium-rich (Fo98.8 +/- 1.2, n = 36; Fs2.3 +/- 2.1 Wo1.2 +/- 0.3, n = 23). Matrix comprises ~40 vol% of the sample and is composed of a micron sized silicate groundmass with larger silicate, sulfide, magnetite, and Fe-Ni metal (Ni ~50 wt%) grains. Phyllosilicates were not observed in the matrix. Refractory inclusions are rare (0.3 vol%) and are spinel pyroxene aggregates or amoeboid olivine aggregates; melilite is absent from the refractory inclusions. Sahara 00182 contains predominantly type 1 PO chondrules, POP chondrules are less common. Most chondrules contain blebs of, and are often rimmed with, Fe-Ni metal and sulfide. Chondrule phenocrysts are magnesium-rich (Fo92.2 +/- 0.6, n = 129; Fs4.4 +/- 1.8 Wo1.3 +/- 1.1, n = 16). Matrix comprises ~30 vol% of the meteorite and is predominantly sub-micron silicates, with rare larger silicate gains. Matrix Fe-Ni metal (mean Ni = 5.8 wt%) and sulfide grains are up to mm scale. No phyllosilicates were observed in the matrix. Refractory inclusions are rare (1.1 vol%) and melilite is absent. The oxygen isotope composition of NWA 1152 falls within the range of the CV chondrites with ?17O = ?3.43? ?18O = 0.70? and is similar to Sahara 00182, ?17O = ?3.89?, ?18O = ?0.19? (Grossman and Zipfel 2001). Based on mineralogical and petrographic characteristics, we suggest NWA 1152 and Sahara 00182 show many similarities with the CR chondrites, however, oxygen isotopes suggest affinity with the CVs. Thus, neither sample can be assigned to any of the currently known carbonaceous chondrite groups based on traditionally recognized characteristics. Both samples demonstrate the complexity of inter- and intra

  11. COMPARATIVE STUDY ON METAL IONS ADSORPTION ON A LOW COST CARBONACEOUS ADSORBENT KINETIC EQUILIBRIUM AND MECHANISTIC STUDIES

    Directory of Open Access Journals (Sweden)

    S. Arivoli, M. Hema, C. Barathiraja

    2008-01-01

    Full Text Available A carbonaceous adsorbent prepared from an indigenous waste and treated by acid was tested for its efficiency in removing metal ions of Fe(II, Co(II and Ni(II. The process parameters studied included agitation time, initial metal ion concentration, carbon dosage, pH, other ions and temperature. The kinetics of adsorption followed first order reaction equation and the rate was mainly controlled by intraparticle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity obtained from the Langmuir isotherm plots was found around 28mg/g for all selected metal ions at an initial pH of 6. The temperature variation study showed that the metal ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying pH of the metal ion solutions. The type I and II isotherms obtained, positive H0 values, pH dependent results and desorption of metal ions in mineral acid suggests that the adsorption of metal ions on this type of adsorbent involves both chemisorption and physical adsorption mechanisms.

  12. Following the kinetics: iron-oxidizing microbial mats in cold icelandic volcanic habitats and their rock-associated carbonaceous signature.

    Science.gov (United States)

    Cockell, Charles S; Kelly, Laura C; Summers, Stephen; Marteinsson, Viggo

    2011-09-01

    Icelandic streams with mean annual temperatures of less than 5 °C, which receive the cationic products of basaltic rock weathering, were found to host mats of iron-cycling microorganisms. We investigated two representative sites. Iron-oxidizing Gallionella and iron-reducing Geobacter species were present. The mats host a high bacterial diversity as determined by culture-independent methods. β-Proteobacteria, Actinobacteria, α-Proteobacteria, and Bacteroidetes were abundant microbial taxa. The mat contained a high number of phototroph sequences. The carbon compounds in the mat displayed broad G and D bands with Raman spectroscopy. This signature becomes incorporated into the weathered oxidized surface layer of the basaltic rocks and was observed on rocks that no longer host mats. The presence of iron-oxidizing taxa in the stream microbial mats, and the lack of them in previously studied volcanic rocks in Iceland that have intermittently been exposed to surface water flows, can be explained by the kinetic limitations to the extraction of reduced iron from rocks. This type of ecosystem illustrates key factors that control the distribution of chemolithotrophs in cold volcanic environments. The data show that one promising sample type for which the hypothesis of the existence of past life on Mars can be tested is the surface of volcanic rocks that, previously, were situated within channels carved by flowing water. Our results also show that the carbonaceous signatures of life, if life had occurred, could be found in or on these rocks.

  13. Influence of coal-tar sealcoat and other carbonaceous materials on polycyclic aromatic hydrocarbon loading in an urban watershed

    Science.gov (United States)

    Yang, Y.; Van Metre, P.C.; Mahler, B.J.; Wilson, J.T.; Ligouis, B.; Razzaque, M.; Schaeffer, D.J.; Werth, C.J.

    2010-01-01

    Carbonaceous material (CM) particles are the principal vectors transporting polycyclic aromatic hydrocarbons (PAHs) into urban waters via runoff; however, characteristics of CM particles in urban watersheds and their relative contributions to PAH contamination remain unclear. Our objectives were to identify the sources and distribution of CM particles in an urban watershed and to determine the types of CMs that were the dominant sources of PAHs in the lake and stream sediments. Samples of soils, parking lot and street dust, and streambed and lake sediment were collected from the Lake Como watershed in Fort Worth, Texas. Characteristics of CM particles determined by organic petrography and a significant correlation between PAH concentrations and organic carbon in coal tar, asphalt, and soot indicate that these three CM particle types are the major sources and carriers of PAHs in the watershed. Estimates of the distribution of PAHs in CM particles indicate that coal-tar pitch, usedinsomepavementsealcoats, isadominant source of PAHs in the watershed, and contributes as much as 99% of the PAHs in sealed parking lot dust, 92% in unsealed parking lot dust, 88% in commercial area soil, 71% in streambed sediment, and 84% in surficial lake sediment. ?? 2010 American Chemical Society.

  14. Occurrence and possible significance of rare Ti oxides (Magneli phases) in carbonaceous chondrite matrices

    Science.gov (United States)

    Brearley, Adrian J.

    1993-01-01

    Rare, ultrafine-grained Ti oxides (Ti3O5 and the Magneli phases, Ti5O9 and Ti8O15) have been identified by TEM in the CM2 carbonaceous chondrite, Bells, and a carbonaceous chondrite matrix clast from the Nilpena polymict ureilite. In both meteorites the Ti oxides occur in the matrix as isolated grains and clusters of two or more grains. They are euhedral in shape and have grain sizes of 0.05-0.3 micron. Magneli phases have been recently shown to be a common component in some interplanetary dust particles, but this is the first reported occurrence in a meteorite. The morphological properties and grain size of the Ti oxides are consistent with formation by vapor phase condensation either within the solar nebula or possibly in a presolar environment.

  15. Everyone Wins: A Mars-Impact Origin for Carbonaceous Phobos and Deimos

    Science.gov (United States)

    Fries, M.; Welzenbach, L.; Steele, A.

    2016-01-01

    Discussions of Phobos' and Deimos' origin(s) tend to feature an orthogonally opposed pair of observations: dynamical studies which favor coalescence of the moons from an orbital debris ring arising from a large impact on Mars; and reflectance spectroscopy of the moons that indicate a carbonaceous composition that is not consistent with Martian surface materials. One way to reconcile this discrepancy is to consider the option of a Mars-impact origin for Phobos and Deimos, followed by surficial decoration of carbon-rich materials by interplanetary dust particles (IDP). The moons experience a high IDP flux because of their location in Mars' gravity well. Calculations show that accreted carbon is sufficient to produce a surface with reflectance spectra resembling carbonaceous chondrites.

  16. Isotopic evidence for primordial molecular cloud material in metal-rich carbonaceous chondrites

    DEFF Research Database (Denmark)

    van Kooten, Elishevah M. M. E.; Wielandt, Daniel Kim Peel; Schiller, Martin

    2016-01-01

    )Mg*-depleted and (54)Cr-enriched component. This composition is consistent with that expected for thermally unprocessed primordial molecular cloud material before its pollution by stellar-derived (26)Al. The (26)Mg* and (54)Cr compositions of bulk metal-rich chondrites require significant amounts (25...... addition of stellar-derived (26)Al has not been identified yet but may be preserved in planetesimals that accreted in the outer Solar System. We show that metal-rich carbonaceous chondrites and their components have a unique isotopic signature extending from an inner Solar System composition toward a (26......-50%) of primordial molecular cloud matter in their precursor material. Given that such high fractions of primordial molecular cloud material are expected to survive only in the outer Solar System, we infer that, similarly to cometary bodies, metal-rich carbonaceous chondrites are samples of planetesimals...

  17. Hard macrocellular silica Si(HIPE) foams templating micro/macroporous carbonaceous monoliths: applications as lithium ion battery negative electrodes and electrochemical capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Brun, Nicolas [Universite de Bordeaux, Centre de Recherche Paul Pascal, UPR 8641-CNRS, Pessac (France); Universite de Bordeaux, Institut des Sciences Moleculaires CNRS-UMR, Talence (France); Prabaharan, Savari R.S. [Laboratoire de Reactivite et Chimie des Solides, UMR CNRS 6007 Universite de Picardie Jules Verne, Amiens (France); Faculty of Engineering and Computer Science, University of Nottingham, Malaysia Campus Jalan Broga, Semenyih, Selangor (Malaysia); Morcrette, Mathieu [Laboratoire de Reactivite et Chimie des Solides, UMR CNRS 6007 Universite de Picardie Jules Verne, Amiens (France); Sanchez, Clement [Laboratoire de Chimie de la Matiere Condensee de Paris, Universite Paris 06, Paris (France); Pecastaings, Gilles; Soum, Alain [Laboratoire de Chimie des Polymeres Organiques UMR 5629 CNRS, Universite Bordeaux-1, Pessac (France); Derre, Alain; Backov, Renal [Universite de Bordeaux, Centre de Recherche Paul Pascal, UPR 8641-CNRS, Pessac (France); Deleuze, Herve; Birot, Marc [Universite de Bordeaux, Institut des Sciences Moleculaires CNRS-UMR, Talence (France)

    2009-10-09

    By using Si(HIPEs) as hard, exotemplating matrices, interconnected macro-/microporous carbon monolith-type materials with a surface area of around 600 m{sup 2} g{sup -1} are synthesized and shaped. The carbonaceous foams exhibit a conductivity of 20 S cm{sup -1}, addressed with excellent mechanical properties (Young's modulus of 0.2 GPa and toughness of 13 J g{sup -1}, when the carbon core is optimized). The above-mentioned specificities, combined with the fact that the external shape and size can be easily designed on demand, are of primary importance for applications. The functionality of these carbonaceous monoliths is tested as both an electrochemical capacitor and a lithium ion negative electrode. The electrochemical capacitors' voltage-current profiles exhibit a non-ideal rectangular response, confirming the double-layer behavior of the carbon studied, while the charge-discharge current profile of the electric double-layer capacitor is directly proportional to the scan where the current response during charge and discharge exhibits high reversibility. When acting as a lithium ion negative electrode, after initial irreversibility, a good cyclability is obtained, associated with a stable capacity of 200 mA h g{sup -1} during the first 50 cycles at a reasonable current density (C/10). (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  18. Regional radiative impacts of mixed dust and carbonaceous aerosols over West Africa

    Science.gov (United States)

    Malavelle, Florent; Pont, Véronique; Solmon, Fabien; Mallet, Marc; Léon, Jean-François; Liousse, Catherine; Johnson, Ben

    2010-05-01

    Africa is a major source of aerosols at global scale. Two types of aerosols dominate the regional background: biomass burning aerosols as results of combustion of the vegetation and mineral dust aerosols related to erosion of arid soils by wind. These important burdens of aerosols are known to have each one a strong impact on the regional radiative budget. Whereas recent modelling efforts show significant impacts at climatic timescale on West African Monsoon due to the radiative effects of dust aerosols (see Solmon et al 2008 in GRL and references therein), biomass burning radiative effects in this region stand still poorly documented. What about West Africa, during the dry season (december-february) when both biomass burning and dust aerosols are encountered in the atmospheric background ? In that frame, we use ICTP Regional Climate Model versions 3 in order to estimate the radiative forcing due to the external mixing of mineral dust and carbonaceous aerosols from biomass burning, BioFuel and Fossil Fuel combustion during the dry season. Emissions of biomass burning aerosols are taken from new inventories based on SPOT vegetation burnt area products. Optical properties of carboneaceous aerosols are updated thanks to chemical sampling at Djougou during AMMA SOP-0. This presentation focuses on the model efficiency to correctly reproduce the main features concerning aerosols observed during AMMA-SOP0/DABEX field campaigns. It refers to (i) a strong stratification of dust and smoke layers, and (ii) a marked seasonal cycle of aerosol mixture optical properties. Those features are key parameters for modelling the direct and semi direct effects of aerosols over West Africa. Results of simulations indicate that the particular low value of single scattering albedo (SSA) for biomass burning aerosols (~0.81 at 550nm) involves important diabatic heating in the atmosphere. Values of aerosol heating rates are estimated and compared with aircraft measurement from DABEX

  19. Natural Radionuclides and Isotopic Signatures for Determining Carbonaceous Aerosol Sources, Aerosol Lifetimes, and Washout Processes

    International Nuclear Information System (INIS)

    Gaffney, Jeffrey

    2012-01-01

    This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

  20. In Situ Mapping of the Organic Matter in Carbonaceous Chondrites and Mineral Relationships

    Science.gov (United States)

    Clemett, Simon J.; Messenger, S.; Thomas-Keprta, K. L.; Ross, D. K.

    2012-01-01

    Carbonaceous chondrite organic matter represents a fossil record of reactions that occurred in a range of physically, spatially and temporally distinct environments, from the interstellar medium to asteroid parent bodies. While bulk chemical analysis has provided a detailed view of the nature and diversity of this organic matter, almost nothing is known about its spatial distribution and mineralogical relationships. Such information is nevertheless critical to deciphering its formation processes and evolutionary history.

  1. Evaluation of the Total Carbonaceous Biochemical Oxygen Demand Method, Using a Compensated Recording Respirometer

    OpenAIRE

    Heddle, John F.; Tavener, Albert

    1981-01-01

    The total carbonaceous biochemical oxygen demand test is described, and experimental data demonstrating its stoichiometry, precision, and accuracy are presented. The test is more reproducible and faster than the current 5-day biochemical oxygen demand test procedure, and if a respirometer is used, the effects of toxic chemicals, pH changes, and nutrient imbalances can be routinely monitored. The design principles of a multichannel compensated recording respirometer suitable for this test are ...

  2. Carbonaceous aerosol characteristics over Delhi in Northern India: Seasonal variability and possible sources

    Science.gov (United States)

    Srivastava, Atul Kumar; Bisht, Ds; Tiwari, S.

    Carbonaceous aerosols have been the focus of extensive studies during the last decade due to its significant impacts on human health, visibility and climate change. As per Asian regions are concerned, aerosols in south-Asia are gaining considerable importance because of their potential impacts on regional climate, yet their possible sources are poorly understood. Semi-continuous measurements of organic carbon (OC) and elemental carbon (EC) and continuous measurements of black carbon (BC) aerosols were conducted simultaneously at Delhi during the period from January 2011 to May 2012. Delhi is the capital city of India and one of the densely populated and industrialized urban megacities in Asia, located at the Ganga basin in the northern part of India. Being highly polluted region, mass concentrations of OC, EC and BC over Delhi were found to vary from about 6-92 mug m (-3) (mean: 23±16 mug m (-3) ), 3-38 mug m (-3) (mean: 11±7 mug m (-3) ) and 1-24 mug m (-3) (mean: 7±5 mug m (-3) ), respectively during the entire measurement period, with about two times higher concentration during winter as compared to summer. A significant correlation between OC and EC (R=0.95, n=232) and relatively lower OC/EC ratio (range: 1.0-3.6; mean: 2.2±0.5) suggest fossil fuel emission as a dominant source of carbonaceous aerosols over the station. The average mass concentration of EC was found about 38% higher than BC during the study period, which is interestingly different as reported at other locations over Ganga basin. We also determined the associated optical properties of carbonaceous species (e.g. absorption coefficient and mass absorption efficiency) over the station. Significant loading of carbonaceous species over such regions emphasize an urgent need to focus on air quality management and proper impact assessment on health perspective.

  3. Heterogeneities in the solar nebula. [oxygen isotopic composition in carbonaceous chondrites

    Science.gov (United States)

    Clayton, R.; Grossman, L.; Mayeda, T. K.; Onuma, N.

    1974-01-01

    Oxygen isotopic compositions of the high-temperatue phases in carbonaceous chondrites define a mixing line with an O-16 rich component and show little superimposed chemical isotope fractionation. Within a single inclusion in Allende, variations of delta O-18 and delta O-17 of 39% are found. The ordinary chondrites are slightly displaced from the terrestrial fractionation trend, implying that at least 0.2% of the oxygen in terrestrial rocks was derived from the O-16 rich component.

  4. Origin of fine carbonaceous particulate matter in the Western Mediterranean Basin: fossil versus modern sources

    Science.gov (United States)

    Cruz Minguillón, María.; Perron, Nolwenn; Querol, Xavier; Szidat, Sönke; Fahrni, Simon; Wacker, Lukas; Reche, Cristina; Cusack, Michael; Baltensperger, Urs; Prévôt, André S. H.

    2010-05-01

    The present work was carried out in the frame of the international field campaign DAURE (Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean). The objective of this campaign is to study the aerosol pollution episodes occurring at regional scale during winter and summer in the Western Mediterranean Basin. As part of this campaign, this work focuses on identifying the origin of fine carbonaceous aerosols. To this end, fine particulate matter (PM1) samples were collected during two different seasons (February-March and July 2009) at two sites: an urban site (Barcelona, NE Spain) and a rural European Supersite for Atmospheric Aerosol Research (Montseny, NE Spain). Subsequently, 14C analyses were carried out on these samples, both in the elemental carbon (EC) fraction and the organic carbon (OC) fraction, in order to distinguish between modern carbonaceous sources (biogenic emissions and biomass burning emissions) and fossil carbonaceous sources (mainly road traffic). Preliminary results from the winter period show that 40% of the OC at Barcelona has a fossil origin whereas at Montseny this percentage is 30%. These values can be considered as unexpected given the nature of the sites. Nevertheless, the absolute concentrations of fossil OC at Barcelona and Montseny differ by a factor of 2 (the first being higher), since the total OC at Montseny is lower than at Barcelona. Further evaluation of results and comparison with other measurements carried out during the campaign are required to better evaluate the origin of the fine carbonaceous matter in the Western Mediterranean Basin. Acknowledgements: Spanish Ministry of Education and Science, for a Postdoctoral Grant awarded to M.C. Minguillón in the frame of Programa Nacional de Movilidad de Recursos Humanos del Plan nacional de I-D+I 2008-2011. Spanish Ministry of Education and Science, for the Acción Complementaria DAURE CGL2007-30502-E/CLI.

  5. Natural Radionuclides and Isotopic Signatures for Determining Carbonaceous Aerosol Sources, Aerosol Lifetimes, and Washout Processes

    Energy Technology Data Exchange (ETDEWEB)

    Gaffney, Jeffrey [Univ. of Arkansas, Little Rock, AR (United States)

    2012-12-12

    This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

  6. Enhanced Removal of Lead by Chemically and Biologically Treated Carbonaceous Materials

    Directory of Open Access Journals (Sweden)

    Mohamed E. Mahmoud

    2012-01-01

    Full Text Available Hybrid sorbents and biosorbents were synthesized via chemical and biological treatment of active carbon by simple and direct redox reaction followed by surface loading of baker’s yeast. Surface functionality and morphology of chemically and biologically modified sorbents and biosorbents were studied by Fourier Transform Infrared analysis and scanning electron microscope imaging. Hybrid carbonaceous sorbents and biosorbents were characterized by excellent efficiency and superiority toward lead(II sorption compared to blank active carbon providing a maximum sorption capacity of lead(II ion as 500 μmol g−1. Sorption processes of lead(II by these hybrid materials were investigated under the influence of several controlling parameters such as pH, contact time, mass of sorbent and biosorbent, lead(II concentration, and foreign ions. Lead(II sorption mechanisms were found to obey the Langmuir and BET isotherm models. The potential applications of chemically and biologically modified-active carbonaceous materials for removal and extraction of lead from real water matrices were also studied via a double-stage microcolumn technique. The results of this study were found to denote to superior recovery values of lead (95.0–99.0±3.0–5.0% by various carbonaceous-modified-bakers yeast biosorbents.

  7. AFM measurements of adhesive forces between carbonaceous particles and the substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tianqi [Institute of Nuclear and New Energy Technology of Tsinghua University, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Beijing 100084 (China); Peng, Wei, E-mail: pengwei@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology of Tsinghua University, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Beijing 100084 (China); Shen, Ke [Institute of Nuclear and New Energy Technology of Tsinghua University, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Beijing 100084 (China); Yu, Suyuan, E-mail: suyuan@tsinghua.edu.cn [Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of Ministry of Educations, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)

    2015-11-15

    Highlights: • Adhesive force of spherical carbonaceous particle MCMBs and HTR-10 graphite matrix debris were measured for the first time. • The measured equivalent works of adhesion were much smaller than the ideal values. • The shape factor and the particle morphology reduce the adhesive force. • The adhesion effect does not change directly with the asperity size. - Abstract: Graphite dust is carbonaceous particles generated during operation of High Temperature Gas-Cooled Reactors (HTR). Graphite dust resuspension is the key behavior associated with HTR source term analyses and environmental safety assessment. The adhesive force is the key factor that determines the resuspension rate. The present study used an atomic force microscope (AFM) to measure the adhesive force between a single carbonaceous particle and the substrate. The measurements were performed on mica, graphite IG110 and Inconel 800H. The prepared “probe cantilevers” were mesocarbon microbeads (MCMB), fuel element debris from HTR-10 and graphite NBG18. The equivalent work of adhesion was derived from the measured adhesive force and calculated based on substrate profile approximation and the JKR theoretical model. The measured work was smaller than the ideal work of adhesion, most likely due to the rough particle morphology and the rough substrate surface. Additionally, a shape factor imposes a constraint on the lateral deformation of the particles. Furthermore, surface roughness could reduce the adhesive force some depending on the particle size. Once the particle was too small to be trapped into a trough, the adhesive force would not be further reduced.

  8. Atmospheric carbonaceous aerosols from Indo-Gangetic Plain and Central Himalaya: impact of anthropogenic sources.

    Science.gov (United States)

    Ram, Kirpa; Sarin, M M

    2015-01-15

    In the present-day scenario of growing anthropogenic activities, carbonaceous aerosols contribute significantly (∼20-70%) to the total atmospheric particulate matter mass and, thus, have immense potential to influence the Earth's radiation budget and climate on a regional to global scale. In addition, formation of secondary organic aerosols is being increasingly recognized as an important process in contributing to the air-pollution and poor visibility over urban regions. It is, thus, essential to study atmospheric concentrations of carbonaceous species (EC, OC and WSOC), their mixing state and absorption properties on a regional scale. This paper presents the comprehensive data on emission sources, chemical characteristics and optical properties of carbonaceous aerosols from selected urban sites in the Indo-Gangetic Plain (IGP) and from a high-altitude location in the central Himalaya. The mass concentrations of OC, EC and WSOC exhibit large spatio-temporal variability in the IGP. This is attributed to seasonally varying emissions from post-harvest agricultural-waste burning, their source strength, boundary layer dynamics and secondary aerosol formation. The high concentrations of OC and SO4(2-), and their characteristic high mass scattering efficiency, contribute significantly to the aerosol optical depth and scattering coefficient. This has implications to the assessment of single scattering albedo and aerosol radiative forcing on a regional scale. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Spectro-microscopic measurements of carbonaceous aerosol aging in Central California

    Directory of Open Access Journals (Sweden)

    R. C. Moffet

    2013-10-01

    Full Text Available Carbonaceous aerosols are responsible for large uncertainties in climate models, degraded visibility, and adverse health effects. The Carbonaceous Aerosols and Radiative Effects Study (CARES was designed to study carbonaceous aerosols in the natural environment of the Central Valley, California, and learn more about their atmospheric formation and aging. This paper presents results from spectro-microscopic measurements of carbonaceous particles collected during CARES at the time of a pollution accumulation event (27–29 June 2010, when in situ measurements indicated an increase in the organic carbon content of aerosols as the Sacramento urban plume aged. Computer-controlled scanning electron microscopy coupled with an energy dispersive X-ray detector (CCSEM/EDX and scanning transmission X-ray microscopy coupled with near-edge X-ray absorption spectroscopy (STXM/NEXAFS were used to probe the chemical composition and morphology of individual particles. It was found that the mass of organic carbon on individual particles increased through condensation of secondary organic aerosol. STXM/NEXAFS indicated that the number fraction of homogenous organic particles lacking inorganic inclusions (greater than ~50 nm equivalent circular diameter increased with plume age, as did the organic mass per particle. Comparison of the CARES spectro-microscopic dataset with a similar dataset obtained in Mexico City during the MILAGRO campaign showed that fresh particles in Mexico City contained three times as much carbon as those sampled during CARES. The number fraction of soot particles at the Mexico City urban site (ranging from 16.6 to 47.3% was larger than at the CARES urban site (13.4–15.7%, and the most aged samples from CARES contained fewer carbon–carbon double bonds. Differences between carbonaceous particles in Mexico City and California result from different sources, photochemical conditions, gas phase reactants, and secondary organic aerosol

  10. Distribution and direct radiative forcing of carbonaceous and sulfate aerosols in an interactive size-resolving aerosol-climate model

    Science.gov (United States)

    Kim, Dongchul; Wang, Chien; Ekman, Annica M. L.; Barth, Mary C.; Rasch, Phil J.

    2008-08-01

    A multimode, two-moment aerosol model has been incorporated in the NCAR CAM3 to develop an interactive aerosol-climate model and to study the impact of anthropogenic aerosols on the global climate system. Currently, seven aerosol modes, namely three for external sulfate and one each for external black carbon (BC), external organic carbon (OC), sulfate/BC mixture (MBS; with BC core coated by sulfate shell), and sulfate/OC mixture (MOS; a uniform mixture of OC and sulfate) are included in the model. Both mass and number concentrations of each aerosol mode, as well as the mass of carbonaceous species in the mixed modes, are predicted by the model so that the chemical, physical, and radiative processes of various aerosols can be formulated depending on aerosol's size, chemical composition, and mixing state. Comparisons of modeled surface and vertical aerosol concentrations, as well as the optical depth of aerosols with available observations and previous model estimates, are in general agreement. However, some discrepancies do exist, likely caused by the coarse model resolution or the constant rates of anthropogenic emissions used to test the model. Comparing to the widely used mass-only method with prescribed geometric size of particles (one-moment scheme), the use of prognostic size distributions of aerosols based on a two-moment scheme in our model leads to a significant reduction in optical depth and thus the radiative forcing at the top of the atmosphere (TOA) of particularly external sulfate aerosols. The inclusion of two types of mixed aerosols alters the mass partitioning of carbonaceous and sulfate aerosol constituents: about 35.5%, 48.5%, and 32.2% of BC, OC, and sulfate mass, respectively, are found in the mixed aerosols. This also brings in competing effects in aerosol radiative forcing including a reduction in atmospheric abundance of BC and OC due to the shorter lifetime of internal mixtures (cooling), a mass loss of external sulfate to mixtures (warming

  11. Nowe zasady działalności firm audytorskich

    Directory of Open Access Journals (Sweden)

    Kazimierz Sawicki

    2009-03-01

    Full Text Available W artykule przedstawiono zmiany, stanowiące implementację Dyrektywy 2006/43/WE Unii Europejskiej w części dotyczącej funkcjonowania firm audytorskich w Polsce. Zgłoszono uwagi popierające nowe rozwiązania, jak też zawierające wątpliwości dotyczące skuteczności ich stosowania w praktyce.

  12. Program GICC, final report (March 2005), inventory of carbonaceous aerosol particles from 1860 to 2100 or which carbonaceous aerosol for a significant climatic regional/global impact?

    International Nuclear Information System (INIS)

    Cachier, H.; Guinot, B.; Criqui, P.; Mima, S.; Brignon, J.M.; Penner, J.; Carmichael, G.; Gadi, R.; Denier Van der Gon, H.; Gregoire, J.M.; Liousse, C.; Michel, C.; Guillaume, B.; Junker, C.

    2007-01-01

    The aim of our program is to determine past, present and future emission inventories of carbonaceous particles from 1860 to 2100 for fossil fuel and biofuel sources. Emission inventories for savannah and forest fires have been developed by using burnt area products given by satellite for Asia and Africa. The strong collaboration with the different groups attending this GICC program has allowed to develop the following results. 1- With the improvement of algorithms and new choices for emission factors, emission inventories for black carbon (BC), primary organic carbon (OCp) and total organic carbon (OCtot) have been constructed for the period 1950 to 1997 for fossil fuel and biofuel sources. With these new development, biofuel sources have been seen to be significant, especially in the developing countries. 2- Past inventories have been developed for fossil fuel and biofuel sources from 1860 to 1997 by taking into account the evolution of fuel consumption, fuel use and emission factors. 3- Savannah and forest fire inventories have been constructed based on burnt area products, for Africa (1981-1991, 2000) and Asia (2000-2001). These results show the importance of using real time data instead of statistics. 4-Future emission inventory of black carbon by fossil fuel sources has been constructed for 2100 following the IPCC scenario A2 (catastrophic case) and B1 (perfect world). 5-Characterization of biofuel emissions has been realized by organizing an experiment in a combustion chamber where indian and chinese biofuels (fuelwood, agricultural wastes, dung-cake etc..). were burnt, reproducing the burning methods used in these countries. 6-Finally, the differences between the existing inventories of carbonaceous aerosols has been explained. (A.L.B.)

  13. Relações entre ciência, tecnologia e sociedade em museus de ciências

    OpenAIRE

    Djana Contier

    2009-01-01

    Este trabalho analisa como museus de ciências no Brasil exploram as relações e as interferências mútuas entre ciência, tecnologia e sociedade, utilizando como principais referenciais a educação com enfoque ciência, tecnologia e sociedade (CTS), e a comunicação pública da ciência. A escolha da educação com enfoque CTS está relacionada à discussão sobre a importância da formação de cidadãos críticos diante das questões de ciência e tecnologia (C&T), incluindo a abordagem ciência, tecnologia, so...

  14. Calcium-aluminum-rich inclusions recycled during formation of porphyritic chondrules from CH carbonaceous chondrites

    Science.gov (United States)

    Krot, Alexander N.; Nagashima, Kazuhide; van Kooten, Elishevah M. M.; Bizzarro, Martin

    2017-03-01

    We report on the mineralogy, petrography, and O-isotope compositions of ∼60 Ca, Al-rich inclusions (CAIs) incompletely melted during formation of porphyritic chondrules from the CH metal-rich carbonaceous chondrites and Isheyevo (CH/CB). These include (i) relict polymineralic CAIs in porphyritic chondrules, (ii) CAIs surrounded by chondrule-like igneous rims, (iii) igneous pyroxene-rich and Type C-like CAIs, and (iv) plagioclase-rich chondrules with clusters of relict spinel grains. 26Al-26Mg systematics were measured in 10 relict CAIs and 11 CAI-bearing plagioclase-rich chondrules. Based on the mineralogy, the CH CAIs incompletely melted during chondrule formation can be divided into grossite-rich (n = 13), hibonite-rich (n = 11), spinel ± melilite-rich (n = 33; these include plagioclase-rich chondrules with clusters of relict spinel grains) types. Mineralogical observations indicate that these CAIs were mixed with different proportions of ferromagnesian silicates and experienced incomplete melting and gas-melt interaction during chondrule formation. These processes resulted in partial or complete destruction of the CAI Wark-Lovering rims, replacement of melilite by Na-bearing plagioclase, and dissolution and overgrowth of nearly end-member spinel by chromium- and iron-bearing spinel. Only two relict CAIs and two CAI-bearing chondrules show resolvable excess of radiogenic 26Mg; the inferred initial 26Al/27Al ratios are (1.7 ± 1.3) × 10-6, (3.7 ± 3.1) × 10-7, (1.9 ± 0.9) × 10-6 and (4.9 ± 2.6) × 10-6. There is a large range of Δ17O among the CH CAIs incompletely melted during chondrule formation, from ∼-37‰ to ∼-5‰; the unmelted minerals in individual CAIs, however, are isotopically uniform and systematically 16O-enriched relative to the host chondrules and chondrule-like igneous rims, which have Δ17O ranging from ∼-7‰ to ∼+4‰. Most of the CH CAIs incompletely melted during chondrule formation are mineralogically and isotopically

  15. Role of apolipoprotein CI in lipid metabolism and bacterial sepsis

    NARCIS (Netherlands)

    Berbée, Jimmy Fransiscus Paulus

    2007-01-01

    The research described in this thesis focussed on the role of apolipoproteins in lipid metabolism, inflammation and bacterial sepsis, with specific emphasis on apoCI. From studies in human APOC1¬-transgenic and apoc1-/- mice, we were able to identify apoCI as a potent inhibitor of triglyceride

  16. Microfossils, biomolecules and biominerals in carbonaceous meteorites: implications to the origin of life

    Science.gov (United States)

    Hoover, Richard B.

    2012-11-01

    Environmental and Field Emission Scanning Electron Microscopy (ESEM and FESEM) investigations have shown that a wide variety of carbonaceous meteorites contain the remains of large filaments embedded within freshly fractured interior surfaces of the meteorite rock matrix. The filaments occur singly or in dense assemblages and mats and are often encased within carbon-rich, electron transparent sheaths. Electron Dispersive X-ray Spectroscopy (EDS) spot analysis and 2D X-Ray maps indicate the filaments rarely have detectable nitrogen levels and exhibit elemental compositions consistent with that interpretation that of the meteorite rock matrix. Many of the meteorite filaments are exceptionally well-preserved and show evidence of cells, cell-wall constrictions and specialized cells and processes for reproduction, nitrogen fixation, attachment and motility. Morphological and morphometric analyses permit many of the filaments to be associated with morphotypes of known genera and species of known filamentous trichomic prokaryotes (cyanobacteria and sulfur bacteria). The presence in carbonaceous meteorites of diagenetic breakdown products of chlorophyll (pristane and phytane) along with indigenous and extraterrestrial chiral protein amino acids, nucleobases and other life-critical biomolecules provides strong support to the hypothesis that these filaments represent the remains of cyanobacteria and other microorganisms that grew on the meteorite parent body. The absence of other life-critical biomolecules in the meteorites and the lack of detectable levels of nitrogen indicate the filaments died long ago and can not possibly represent modern microbial contaminants that entered the stones after they arrived on Earth. This paper presents new evidence for microfossils, biomolecules and biominerals in carbonaceous meteorites and considers the implications to some of the major hypotheses for the Origin of Life.

  17. Carbon isotope analysis of carbonaceous compounds in Puget Sound and Lake Washington

    International Nuclear Information System (INIS)

    Swanson, J.R.

    1980-01-01

    A new method has been developed and tested for determining chronological profiles of organic pollutants. This method, Carbon Isotope Analysis (CIA), involves measurements of 12 C, 13 C and 14 C in carbonaceous compounds found in layers of sediment. Lipids, total aliphatic hydrocarbons (TAHs) and polycyclic aromatic hydrocarbons (PAHs) are separated from kg quantities of sediment. Large Soxhlet extractors are used to remove the extractable organics, using ultra-pure benzene-methanol solution and having an extraction efficiency of about 86% for compounds with boiling points higher than n-tetradecane (n-C 14 ). The basic steps in compound separation include freeze-drying, extraction, fractionation, column chromatography and evaporation. Isolating the TAH and PAH fractions is accomplished by eluting samples from Sephadex and alumina/silica-gel columns. The amount of each fraction recovered is determined by converting the hydrocarbons to carbon dioxide and measuring this gas manometrically. Variations in 12 C and 13 C abundances for carbonaceous compounds are primarily due to thermodynamic, photosynthetic and metabolic fractionation processes. Thus, the source of a particular organic compound can often be determined by measuring its 13 C/ 12 C ratio. Combining the information from both the 13 C analysis and 14 C analysis makes source identification more certain. In addition, this investigation reviews carbon isotopic data and carbon cycling and analyzes organic pollution in two limited ecosystems (Puget Sound and Lake Washington). Specifically, distinct carbonaceous species are analyzed for pollution in sediments of Lake Washington, Elliott Bay, Commencement Bay, central Puget Sound and northern Puget Sound near the Cherry Point oil refineries

  18. Indigenous Carbonaceous Phases Embedded Within Surface Deposits on Apollo 17 Volcanic Glass Beads

    Science.gov (United States)

    Thomas-Keprta, K. L.; Clemett, S. J.; Ross, D. K.; Le, L.; McKay, D. S.; Gibson, E. K.; Gonzalez, C.

    2012-01-01

    The assessment of indigenous organic matter in returned lunar samples was one of the primary scientific goals of the Apollo program. Prior studies of Apollo samples have shown the total amount of organic matter to be in the range of approx 50 to 250 ppm. Low concentrations of lunar organics may be a consequence not only of its paucity but also its heterogeneous distribution. Several processes should have contributed to the lunar organic inventory including exogenous carbonaceous accretion from meteoroids and interplanetary dust particles, and endogenous synthesis driven by early planetary volcanism and cosmic and solar radiation.

  19. Quenched carbonaceous composite - Fluorescence spectrum compared to the extended red emission observed in reflection nebulae

    Science.gov (United States)

    Sakata, Akira; Wada, Setsuko; Narisawa, Takatoshi; Asano, Yoichi; Iijima, Yutaka; Onaka, Takashi; Tokunaga, Alan T.

    1992-01-01

    The photoluminescence (fluorescence) of a film of the laboratory-synthesized quenched carbonaceous composite (filmy QCC) is shown to have a single broad emission feature with a peak wavelength that varies from 670 to 725 nm, and coincides with that of the extended red emission observed in reflection nebulae. The rapid decay of the filmy QCC red fluorescence in air and of the stable blue fluorescence of the filmy QCC dissolved in liquid Freon suggests that the red fluorescence originates from the interaction of active chemical species and aromatic components in the filmy QCC. A material similar in nature to that of the filmy QCC may be a major component of interstellar dust.

  20. CO2 Separation and Capture Properties of Porous Carbonaceous Materials from Leather Residues

    Directory of Open Access Journals (Sweden)

    Ana Arenillas

    2013-10-01

    Full Text Available Carbonaceous porous materials derived from leather skin residues have been found to have excellent CO2 adsorption properties, with interestingly high gas selectivities for CO2 (α > 200 at a gas composition of 15% CO2/85% N2, 273K, 1 bar and capacities (>2 mmol·g−1 at 273 K. Both CO2 isotherms and the high heat of adsorption pointed to the presence of strong binding sites for CO2 which may be correlated with both: N content in the leather residues and ultrasmall pore sizes.

  1. CO2 Separation and Capture Properties of Porous Carbonaceous Materials from Leather Residues

    Science.gov (United States)

    Bermúdez, José M.; Dominguez, Pablo Haro; Arenillas, Ana; Cot, Jaume; Weber, Jens; Luque, Rafael

    2013-01-01

    Carbonaceous porous materials derived from leather skin residues have been found to have excellent CO2 adsorption properties, with interestingly high gas selectivities for CO2 (α > 200 at a gas composition of 15% CO2/85% N2, 273K, 1 bar) and capacities (>2 mmol·g−1 at 273 K). Both CO2 isotherms and the high heat of adsorption pointed to the presence of strong binding sites for CO2 which may be correlated with both: N content in the leather residues and ultrasmall pore sizes. PMID:28788352

  2. Electrical conductivity of carbonaceous chondrites and electric heating of meteorite parent bodies

    Science.gov (United States)

    Duba, AL

    1987-01-01

    Electromagnetic heating of rock-forming materials most probably was an important process in the early history of the solar system. Electrical conductivity experiments of representative materials such as carbonaceous chondrites are necessary to obtain data for use in electromagnetic heating models. With the assumption that carbon was present at grain boundaries in the material that comprised the meteorite parent bodies, the electrical heating of such bodies was calculated as a function of body size and solar distance using the T-Tauri model of Sonett and Herbert (1977). The results are discussed.

  3. Radiocarbon source apportionment of carbonaceous aerosol components of South Asian Atmospheric Brown Clouds

    Science.gov (United States)

    Gustafsson, Örjan; Krusâ, Martin; Sheesley, Rebecca; Praveen, P. S.; Rao, P. S. P.; Safai, P. D.; Budhavant, K.; Rengarajan, R.; Sudheer, A. K.; Sarin, M. M.

    2010-05-01

    Light-absorbing carbonaceous matter constitutes one of the largest uncertainties in climate modeling. The high concentrations of black carbon - soot - in South Asian Atmospheric Brown Clouds lead to strong atmospheric heating and large surface cooling that is as important to regional climate forcing as greenhouse gases, yet the sources of these aerosols are not well understood. Emission inventory models suggest that biofuel/biomass burning accounts for 60-90% of the sources of these aerosol components whereas measurements of the elemental composition of ambient aerosols compared with source signatures point to combustion of fossil fuel as the primary culprit. However, both approaches acknowledge large uncertainties in source apportionment of the elusively-defined black carbon. This study approached the sourcing challenge by applying microscale radiocarbon measurements to aerosol particles collected during the winter in North India, Central India and over the Indian Ocean receptor (The Maldives). The radiocarbon approach is ideally suited to this task as fossil sources are void of 14C whereas biomass combustion products hold a contemporary 14C signal. In a first pilot study in 2006, high-volume air samples of total carbonaceous aerosols revealed 14C signals that were similar for a Central Indian source region site located in Sinighad, near Pune, and an Indian Ocean receptor (the Maldives), consistent with the absence of any significant formation of secondary organic aerosols, with a 60-70% contribution from biomass combustion and biogenic sources. Isolates of elemental or soot carbon fractions varied between 40-70%, depending on isolation method. A subsequent 15-month continuous probing of these two sites in 2008-2009 confirmed an average contribution of two-thirds from contemporary sources to the TOC. The 14C-data revealed a stronger contemporary signal arriving to the Maldives in May-June, presumably due to biogenic secondary organic aerosols. A period of stronger

  4. Studying properties of carbonaceous reducers and process of forming primary titanium slags

    Directory of Open Access Journals (Sweden)

    T. K. Balgabekov

    2014-10-01

    Full Text Available When smelting a rich titanium slag the most suitable are low-ash reducers, and the studies revealed the suitability for this purpose of special coke and coal. An important property of a reducer is its specific resistance. Therefore there were carried out studies for measuring electric resistance of briquettes consisting of ilmenite concentrate and different carbonaceous reducers. It is recommended to jointly smelt the briquetted and powdered burden (the amount of the powdered burden varies form 20 tо 50 %, this leads to the increase of technical-economic indicators of the process.

  5. Special Issue for the 9th International Conference on Carbonaceous Particles in the Atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Strawa, A.W.; Kirchstetter, T.W.; Puxbaum, H.

    2009-12-11

    Carbonaceous particles are a minor constituent of the atmosphere but have a profound effect on air quality, human health, visibility and climate. The importance of carbonaceous particles has been increasingly recognized and become a mainstream topic at numerous conferences. Such was not the case in 1978, when the 1st International Conference on Carbonaceous Particles in the Atmosphere (ICCPA), or ''Carbon Conference'' as it is widely known, was introduced as a new forum to bring together scientists who were just beginning to reveal the importance and complexity of carbonaceous particles in the environment. Table 1 lists the conference dates, venues in the series as well as the proceedings, and special issues resulting form the meetings. Penner and Novakov (Penner and Novakov, 1996) provide an excellent historical perspective to the early ICCPA Conferences. Thirty years later, the ninth in this conference series was held at its inception site, Berkeley, California, attended by 160 scientists from 31 countries, and featuring both new and old themes in 49 oral and 83 poster presentations. Topics covered such areas as historical trends in black carbon aerosol, ambient concentrations, analytic techniques, secondary aerosol formation, biogenic, biomass, and HULIS1 characterization, optical properties, and regional and global climate effects. The conference website, http://iccpa.lbl.gov/, holds the agenda, as well as many presentations, for the 9th ICCPA. The 10th ICCPA is tentatively scheduled for 2011 in Vienna, Austria. The papers in this issue are representative of several of the themes discussed in the conference. Ban-Weiss et al., (Ban-Weiss et al., accepted) measured the abundance of ultrafine particles in a traffic tunnel and found that heavy duty diesel trucks emit at least an order of magnitude more ultrafine particles than light duty gas-powered vehicles per unit of fuel burned. Understanding of this issue is important as ultrafine particles

  6. Density functional theory study the effects of oxygen-containing functional groups on oxygen molecules and oxygen atoms adsorbed on carbonaceous materials.

    Science.gov (United States)

    Qi, Xuejun; Song, Wenwu; Shi, Jianwei

    2017-01-01

    Density functional theory was used to study the effects of different types of oxygen-containing functional groups on the adsorption of oxygen molecules and single active oxygen atoms on carbonaceous materials. During gasification or combustion reactions of carbonaceous materials, oxygen-containing functional groups such as hydroxyl(-OH), carbonyl(-CO), quinone(-O), and carboxyl(-COOH) are often present on the edge of graphite and can affect graphite's chemical properties. When oxygen-containing functional groups appear on a graphite surface, the oxygen molecules are strongly adsorbed onto the surface to form a four-member ring structure. At the same time, the O-O bond is greatly weakened and easily broken. The adsorption energy value indicates that the adsorption of oxygen molecules changes from physisorption to chemisorption for oxygen-containing functional groups on the edge of a graphite surface. In addition, our results indicate that the adsorption energy depends on the type of oxygen-containing functional group. When a single active oxygen atom is adsorbed on the bridge site of graphite, it gives rise to a stable epoxy structure. Epoxy can cause deformation of the graphite lattice due to the transition of graphite from sp2 to sp3 after the addition of an oxygen atom. For quinone group on the edge of graphite, oxygen atoms react with carbon atoms to form the precursor of CO2. Similarly, the single active oxygen atoms of carbonyl groups can interact with edge carbon atoms to form the precursor of CO2. The results show that oxygen-containing functional groups on graphite surfaces enhance the activity of graphite, which promotes adsorption on the graphite surface.

  7. Characteristics and determinants of music appreciation in adult CI users.

    Science.gov (United States)

    Philips, Birgit; Vinck, Bart; De Vel, Eddy; Maes, Leen; D'Haenens, Wendy; Keppler, Hannah; Dhooge, Ingeborg

    2012-03-01

    The main objective of this study was to assess the associations between self-reported listening habits and perception of music and speech perception outcomes in quiet and noise for both unilateral cochlear implant (CI) users and bimodal (CI in one ear, hearing aid in contra-lateral ear) users. Information concerning music appreciation was gathered by means of a newly developed questionnaire. Moreover, audiological data (pure-tone audiometry, speech tests in noise and quiet) were gathered and the relationship between speech perception and music appreciation is studied. Bimodal users enjoy listening to music more in comparison with unilateral CI users. Also, music training within rehabilitation is still uncommon, while CI recipients believe that music training might be helpful to maximize their potential with current CI technology. Music training should not be exclusively reserved for the good speech performers. Therefore, a music training program (MTP) that consists of different difficulty levels should be developed. Hopefully, early implementation of MTP in rehabilitation programs can enable adult CI users to enjoy and appreciate music and to maximize their potential with commercially available technology. Furthermore, because bimodal users consider the bimodal stimulation to be the most enjoyable way to listen to music, CI users with residual hearing in the contra-lateral ear should be encouraged to continue wearing their hearing aid in that ear.

  8.  Dylematy harmonizacji rachunkowości

    Directory of Open Access Journals (Sweden)

    Jerzy Gierusz

    2015-06-01

    Full Text Available Harmonizacja rachunkowości finansowej jest procesem przynoszącym wiele korzyści, ale także generującym poważne zagrożenia. Wśród pozytywnych stron harmonizacji wymienić należy: wzmocnienie funkcji alokacyjnej rynków kapitałowych, wzrost zaufania inwestorów do sprawozdań finansowych, rozszerzenie możliwości pozyskiwania kapitału pożyczkowego, obniżenie kosztów funkcjonowania korporacji międzynarodowych. Towarzyszące harmonizacji zjawiska niepożądane to: wyeliminowanie porównywalności sprawozdań finansowych na poziomie krajowym, przekreślenie znacznej części dorobku szkoły kontynentalnej rachunkowości, ustanowienie monopolu w tworzeniu standardów, zanik normatywnego nurtu badań w rachunkowości.

  9. Ciência e humanismo : a visão da ciência de Erwin Schröedinger

    OpenAIRE

    Fiolhais, Carlos

    2015-01-01

    "Erwin Schrödinger, o físico austríaco, que foi um dos principais autores da física quântica, realizou em 1950 uma série de conferências intituladas Ciência e humanismo, que estão traduzidas em português. Analisamos aqui a sua visão da ciência como parte do esforço do ser humano em conhecer-se. Debatemos a sua perspectiva da unidade das ciências, a relação entre ciência e técnica, as raízes profundas do pensamento científico na Antiguidade Grega e, além disso, a interacção da ciência com a fi...

  10. Sorption of indigo carmine by a Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Segura, E. [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Paseo Colon y Tollocan s/n., C.P. 50000 Toluca (Mexico); Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Col. Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico); Solache-Rios, M., E-mail: marcos.solache@inin.gob.mx [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Col. Escandon, Delegacion Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico); Colin-Cruz, A. [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Paseo Colon y Tollocan s/n., C.P. 50000 Toluca (Mexico)

    2009-10-30

    Indigo carmine removal from aqueous solution has been evaluated using Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge treated with HCl (CM). The adsorbents were characterized by scanning electron microscopy, BET surface area and X-ray diffraction. Sorption kinetics and isotherms were determined and the adsorption behaviors analyzed. Kinetic pseudo-second order and Langmuir-Freundlich models were successfully applied to the experimental results obtained with the Fe-zeolitic material, while kinetic first order and Langmuir-Freundlich models were applied to the results from the carbonaceous materials. This indicates mechanisms of chemisorption and physic sorption, respectively, on the heterogeneous materials. The results indicate that the carbonaceous material from the pyrolysis of sewage sludge (sorption capacity 92.83 mg/g) is a better adsorbent of indigo carmine than the zeolitic material (sorption capacity 32.83 mg/g).

  11. Sorption of indigo carmine by a Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge

    International Nuclear Information System (INIS)

    Gutierrez-Segura, E.; Solache-Rios, M.; Colin-Cruz, A.

    2009-01-01

    Indigo carmine removal from aqueous solution has been evaluated using Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge treated with HCl (CM). The adsorbents were characterized by scanning electron microscopy, BET surface area and X-ray diffraction. Sorption kinetics and isotherms were determined and the adsorption behaviors analyzed. Kinetic pseudo-second order and Langmuir-Freundlich models were successfully applied to the experimental results obtained with the Fe-zeolitic material, while kinetic first order and Langmuir-Freundlich models were applied to the results from the carbonaceous materials. This indicates mechanisms of chemisorption and physic sorption, respectively, on the heterogeneous materials. The results indicate that the carbonaceous material from the pyrolysis of sewage sludge (sorption capacity 92.83 mg/g) is a better adsorbent of indigo carmine than the zeolitic material (sorption capacity 32.83 mg/g).

  12. Production of activated charcoal beads or green moldnings useful in stationary or fluidized bed uses rotary stirrer(s) for mixing carbonaceous powder with binder

    DEFF Research Database (Denmark)

    2000-01-01

    In the production of activated charcoal beads or green moldings by mixing carbonaceous powder with a binder, mixing is carried out in a stirred vessel with rotary stirrer(s).......In the production of activated charcoal beads or green moldings by mixing carbonaceous powder with a binder, mixing is carried out in a stirred vessel with rotary stirrer(s)....

  13. Wrap it in rap! - Music Making with Adolescent CI Users

    DEFF Research Database (Denmark)

    Petersen, Bjørn; Sørensen, Stine Derdau; Pedersen, Ellen Raben

    2015-01-01

    The purpose of this study was to examine 1) the potential effects of an intensive musical ear training program on the perception of music and speech in prelingually hearing impaired adolescent cochlear implant (CI) users and 2) these adolescents’ music engagement. Eleven adolescent CI users...... participated in a short intensive training program involving group-based music making activities (e.g. rapping and singing) and self-administered computer based listening exercises. Testing of music and speech discrimination was carried out before and after the program for the CI users and in two sessions...... equally separated in time for a group of normal-hearing (NH) controls. In addition, the participants reported on their music listening habits and enjoyment. CI users significantly improved their overall music perception and improved their discrimination of melodic contour and rhythm in particular. The NH...

  14. Para quê serve a ciência?

    OpenAIRE

    Novelli, Pedro Geraldo Aparecido [UNESP

    2010-01-01

    A ciência é uma forma de conhecimento e é também uma forma do conhecimento. Contudo, a ciência parece se apresentar como a forma de conhecer e do conhecer. Essa postura faz com que a ciência se afirme no mundo como algo singular obtendo inclusive força de instituição com reconhecimento oficial e sustentação em instâncias informais. A ciência sobreviveu a uma história de perseguição, rejeição e condenação colocando-se nos tempos modernos como o referencial por excelência para o estabelecimento...

  15. Atmospheric pressure MALDI for the noninvasive characterization of carbonaceous ink from Renaissance documents.

    Science.gov (United States)

    Grasso, Giuseppe; Calcagno, Marzia; Rapisarda, Alessandro; D'Agata, Roberta; Spoto, Giuseppe

    2017-06-01

    The analytical methods that are usually applied to determine the compositions of inks from ancient manuscripts usually focus on inorganic components, as in the case of iron gall ink. In this work, we describe the use of atmospheric pressure/matrix-assisted laser desorption ionization-mass spectrometry (AP/MALDI-MS) as a spatially resolved analytical technique for the study of the organic carbonaceous components of inks used in handwritten parts of ancient books for the first time. Large polycyclic aromatic hydrocarbons (L-PAH) were identified in situ in the ink of XVII century handwritten documents. We prove that it is possible to apply MALDI-MS as a suitable microdestructive diagnostic tool for analyzing samples in air at atmospheric pressure, thus simplifying investigations of the organic components of artistic and archaeological objects. The interpretation of the experimental MS results was supported by independent Raman spectroscopic investigations. Graphical abstract Atmospheric pressure/MALDI mass spectrometry detects in situ polycyclic aromatic hydrocarbons in the carbonaceous ink of XVII century manuscripts.

  16. Effect of Annealing on Properties of Carbonaceous Materials. Part II: Porosity and Pore Geometry

    Science.gov (United States)

    Xing, Xing; Zhang, Guangqing; Dell'Amico, Mark; Ciezki, George; Meng, Qingbo; Ostrovski, Oleg

    2013-08-01

    The pore structure of carbonaceous materials was studied using image analysis. The effect of annealing on the porosity and pore geometry of cokes, chars, and pyrolyzed coals (laboratory chars) was examined in the temperature range of 973 K to 1773 K (700 °C to 1500 °C). The porosity of chars and pyrolyzed coals significantly increased during annealing at temperatures below 1373 K (1100 °C) due to volatile matter release. Further increasing of the annealing temperature from 1373 K to 1773 K (1100 °C to 1500 °C) caused marginal porosity evolution. The porosity of cokes was not affected by annealing at temperatures below 1573 K (1300 °C) and slightly increased in the temperature range 1573 to 1773 K (1300 °C to 1500 °C). The increase in the porosity of chars and pyrolyzed coals during annealing at temperatures 1373 K to 1773 K (1100 °C to 1500 °C), and cokes at 1573 K to 1773 K (1300 °C to 1500 °C), was a result of reactions with oxides of their mineral phases. Annealing had a marginal effect on the pore shape (Feret ratio) of carbonaceous materials, but enlarged the pore size of chars and pyrolyzed coals and decreased their pore density.

  17. Sources of non-fossil-fuel emissions in carbonaceous aerosols during early winter in Chinese cities

    Science.gov (United States)

    Liu, Di; Li, Jun; Cheng, Zhineng; Zhong, Guangcai; Zhu, Sanyuan; Ding, Ping; Shen, Chengde; Tian, Chongguo; Chen, Yingjun; Zhi, Guorui; Zhang, Gan

    2017-09-01

    China experiences frequent and severe haze outbreaks from the beginning of winter. Carbonaceous aerosols are regarded as an essential factor in controlling the formation and evolution of haze episodes. To elucidate the carbon sources of air pollution, source apportionment was conducted using radiocarbon (14C) and unique molecular organic tracers. Daily 24 h PM2. 5 samples were collected continuously from October 2013 to November 2013 in 10 Chinese cities. The 14C results indicated that non-fossil-fuel (NF) emissions were predominant in total carbon (TC; average = 65 ± 7 %). Approximately half of the EC was derived primarily from biomass burning (BB) (average = 46 ± 11 %), while over half of the organic carbon (OC) fraction comprised NF (average = 68 ± 7 %). On average, the largest contributor to TC was NF-derived secondary OC (SOCnf), which accounted for 46 ± 7 % of TC, followed by SOC derived from fossil fuels (FF) (SOCf; 16 ± 3 %), BB-derived primary OC (POCbb; 13 ± 5 %), POC derived from FF (POCf; 12 ± 3 %), EC derived from FF (ECf; 7 ± 2 %) and EC derived from BB (ECbb; 6 ± 2 %). The regional background carbonaceous aerosol composition was characterized by NF sources; POCs played a major role in northern China, while SOCs contributed more in other regions. However, during haze episodes, there were no dramatic changes in the carbon source or composition in the cities under study, but the contribution of POC from both FF and NF increased significantly.

  18. The carbonaceous sorbent based on the secondary silica-containing material from oil extraction industry

    Science.gov (United States)

    Starostina, I. V.; Stolyarov, D. V.; Anichina, Ya N.; Porozhnyuk, E. V.

    2018-01-01

    The object of research in this work is the silica-containing waste of oil extraction industry - the waste kieselghur (diatomite) sludge from precoat filtering units, used for the purification of vegetable oils from organic impurities. As a result of the thermal modification of the sludge, which contains up to 70% of organic impurities, a finely-dispersed low-porous carbonaceous mineral sorption material is formed. The modification of the sludge particles surface causes the substantial alteration of its physical, chemical, adsorption and structural properties - the organic matter is charred, the particle size is reduced, and on the surface of diatomite particles a carbon layer is formed, which deposits in macropores and partially occludes them. The amount of mesopores is increased, along with the specific surface of the obtained product. The optimal temperature of sludge modification is 500°C. The synthesized carbonaceous material can be used as an adsorbing agent for the purification of wastewater from heavy metal ions. The sorption capacity of Cu2+ ions amounted to 14.2 mg·g-1 and for Ni2+ ions - 17.0 mg·g-1. The obtained values exceed the sorption capacity values of the initial kieselghur, used as a filtering charge, for the researched metal ions.

  19. Carbonaceous particles in the atmosphere and precipitation of the Nam Co region, central Tibet.

    Science.gov (United States)

    Ming, Jing; Xiao, Cunde; Sun, Junying; Kang, Shichang; Bonasoni, Paolo

    2010-01-01

    A continuous air and precipitation sampling for carbonaceous particles was conducted in a field observatory beside Nam Co, Central Tibetan Plateau during July of 2006 through January of 2007. Organic carbon (OC) was the dominant composition of the carbonaceous particles both in the atmosphere (1660 ng/m3) and precipitation (476 ng/g) in this area, while the average elemental carbon (BC) concentrations in the atmosphere and precipitation were only 82 ng/m3 and 8 ng/g, respectively. Very high OC/BC ratio suggested local secondary organic carbon could be a dominant contribution to OC over the Nam Co region, while BC could be mainly originated from Southern Asia, as indicated by trajectory analysis and aerosol optical depth. Comparison between the BC concentrations measured in Lhasa, those at "Nepal Climate Observatory at Pyramid (NCO-P)" site on the southern slope of the Himalayas, and Nam Co suggested BC in the Nam Co region reflected a background with weak anthropogenic disturbances and the emissions from Lhasa might have little impact on the atmospheric environment here, while the pollutants from the Indo-Gangetic Basin of Southern Asia could be transported to the Nam Co region by both the summer monsoon and the westerly.

  20. Enantiomer excesses of rare and common sugar derivatives in carbonaceous meteorites

    Science.gov (United States)

    Cooper, George; Rios, Andro C.

    2016-06-01

    Biological polymers such as nucleic acids and proteins are constructed of only one—the d or l—of the two possible nonsuperimposable mirror images (enantiomers) of selected organic compounds. However, before the advent of life, it is generally assumed that chemical reactions produced 50:50 (racemic) mixtures of enantiomers, as evidenced by common abiotic laboratory syntheses. Carbonaceous meteorites contain clues to prebiotic chemistry because they preserve a record of some of the Solar System’s earliest (˜4.5 Gy) chemical and physical processes. In multiple carbonaceous meteorites, we show that both rare and common sugar monoacids (aldonic acids) contain significant excesses of the d enantiomer, whereas other (comparable) sugar acids and sugar alcohols are racemic. Although the proposed origins of such excesses are still tentative, the findings imply that meteoritic compounds and/or the processes that operated on meteoritic precursors may have played an ancient role in the enantiomer composition of life’s carbohydrate-related biopolymers.

  1. Preliminary Results of the Investigation of the Carbonaceous Chondrites Nagoya, Allende, and Murray

    Science.gov (United States)

    Rozanov, Alexei Yu.; Hoover, Richard B.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    As part of a long-term study of morphological biomarkers in Astromaterials, we are documenting a variety of features considered to be indigenous to ancient terrestrial rocks and carbonaceous meteorites. In preparation for the study of samples returned from Mars and other bodies of our Solar System, it is imperative that we establish a database of the nature and morphology of known bacterial fossils in Earth rocks and biomorphic microstructures which may represent microfossils in meteorites. The process of fossilization or mineralization can cause major changes in morphologies and textures of the original organisms and the study of fossilized terrestrial organisms can help provide insight into the interpretation of mineral biomarkers and abiotic microstructures which may mimic certain aspects of microfossils. One class of biomarkers consists of biominerals which have either been precipitated directly by microorganisms, or whose precipitation has been influenced by the organisms. Such microbe-mediated mineral formation may include important clues to the size, shape, and environment of the microorganisms. This paper describes the detection of possible microbe-mediated minerals, biomorphic microstructures and possible microfossils in the Nagoya, Allende, and Murray Carbonaceous Chondrites.

  2. Proto-Planetary Disk Chemistry Recorded by D-Rich Organic Radicals in Carbonaceous Chondrites

    Science.gov (United States)

    Remusat, Laurent; Robert, François; Meibom, Anders; Mostefaoui, Smail; Delpoux, Olivier; Binet, Laurent; Gourier, Didier; Derenne, Sylvie

    2009-06-01

    Insoluble organic matter (IOM) in primitive carbonaceous meteorites has preserved its chemical composition and isotopic heterogeneity since the solar system formed ~4.567 billion years ago. We have identified the carrier moieties of isotopically anomalous hydrogen in IOM isolated from the Orgueil carbonaceous chondrite. Data from high spatial resolution, quantitative isotopic NanoSIMS mapping of Orgueil IOM combined with data from electron paramagnetic resonance spectroscopy reveals that organic radicals hold all the deuterium excess (relative to the bulk IOM) in distinct, micrometer-sized, D-rich hotspots. Taken together with previous work, the results indicate that an isotopic exchange reaction took place between pre-existing organic compounds characterized by low D/H ratios and D-rich gaseous molecules, such as H2D+ or HD2 +. This exchange reaction most likely took place in the diffuse outer regions of the proto-planetary disk around the young Sun, offering a model that reconciles meteoritic and cometary isotopic compositions of organic molecules.

  3. [Study on pollution characteristics of carbonaceous aerosols in Xi'an City during the spring festival].

    Science.gov (United States)

    Zhou, Bian-Hong; Zhang, Cheng-Zhong; Wang, Ge-Hui

    2013-02-01

    The samples of PM2.5 with 8 times periods were collected using Automated Cartridge Collection Unit (ACCU) of Rupprecht& Patashnick (R&P)Corporation, and monitored by R&P1400a instrument of TEOM series online during 2011 Spring Festival in Xi'an city. The organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC) and water-insoluble organic carbon (WIOC) contents of 3 h integrated PM2.5 were analyzed to evaluate the influence of firework display on the carbonaceous components in urban air. The mass concentration of PM2.5 was found increased significantly from 00:00 A. M. to 02:59 A. M. at the Chinese Lunar New Year's Eve than the non-firework periods, reaching 1514.8 microg.m-3 at 01:00 A. M. The mass concentrations of OC, EC, WSOC, and WIOC during the same time period were 123.3 microg.m-3, 18.6 microg.m-3, 66.7 microg.m-3, and 56.6 microg.m-3, about 1.7, 1.2, 1.4, and 2.2 times higher than the average in normal days, respectively. Correlation analysis among WSOC, OC, and EC contents in PM25 showed that firework emission was an obvious source of carbonaceous aerosol in the Spring Festival vacation. However, it only contributes to 9. 4% for aerosol in fireworks emission.

  4. Zależność bodźcowości ciśnienia od cyrkulacji atmosferycznej w Warszawie

    Directory of Open Access Journals (Sweden)

    Katarzyna Rozbicka

    2016-09-01

    Full Text Available W pracy zbadano: czasowy rozkład ciśnienia atmosferycznego, bodźcowe oddziaływanie ciśnienia atmosferycznego o wartościach wyższych od 1015 hPa lub niższych od 985 hPa. Wyznaczono częstość i prawdopodobieństwo wystąpienia ciśnienia o oddziaływaniu bodźcowym oraz zanalizowano zależność zmian międzydobowych ciśnienia od typów cyrkulacji atmosferycznej według klasyfikacji Lityńskiego. Do obliczeń wykorzystano cogodzinne wartości ciśnienia atmosferycznego pochodzące ze stacji Ursynów SGGW z okresu 2011–2015. Na podstawie badań stwierdzono, że ciśnienie atmosferyczne o oddziaływaniu bodźcowym w Warszawie może wystąpić w każdym miesiącu z prawdopodobieństwem od 0,2% do 19,1%, w przypadku ciśnienia o wartościach wyższych niż 1015 hPa oraz od 0,1 do 3,4%, w przypadku ciśnienia niższego od 985 hPa, z wyjątkiem czerwca i sierpnia. Zmiany międzydobowe ciśnienia atmosferycznego mogą osiągać około 24 hPa, a częstość występowania bodźców „silnych” wywołanych tymi zmianami wyniosła w poszczególnych miesiącach od 1% do 16%, natomiast bodźców „bardzo silnych” od 2% do 8%. Spośród sytuacji synoptycznych największe znaczenie dla bodźcowości zmian ciśnienia mają sytuacje cyklonalne: szczególnie przy adwekcji powietrza z sektora północno-zachodniego (NWC.

  5. Source contributions to carbonaceous species in PM2.5 and their uncertainty analysis at typical urban, peri-urban and background sites in southeast China

    International Nuclear Information System (INIS)

    Niu, Zhenchuan; Wang, Sen; Chen, Jinsheng; Zhang, Fuwang; Chen, Xiaoqiu; He, Chi; Lin, Lifeng; Yin, Liqian; Xu, Lingling

    2013-01-01

    Determination of 14 C and levoglucosan can provide insights into the quantification of source contributions to carbonaceous aerosols, yet there is still uncertainty on the partitioning of organic carbon (OC) into biomass burning OC (OC bb ) and biogenic emission OC (OC bio ). Carbonaceous species, levoglucosan and 14 C in PM 2.5 were measured at three types of site in southeast China combined with Latin hypercube sampling, with the objectives to study source contributions to total carbon (TC) and their uncertainties, and to evaluate the influence of levoglucosan/OC bb ratios on OC bb and OC bio partitioning. It was found reliably that fossil fuel combustion is the main contributor (62.90–72.23%) to TC at urban and peri-urban sites. Biogenic emissions have important contribution (winter, 52.98%; summer, 45.71%) to TC at background site. With the increase in levoglucosan/OC bb ratios, the contribution of OC bio is increased while OC bb is decreased in a pattern of approximate natural logarithm at a given range. -- Highlights: •Source contributions to OC and EC were quantified by levoglucosan and 14 C. •Fossil fuel combustion is the main contributor to TC for urban and peri-urban sites. •Biogenic emissions have important contribution to TC for the background site. •Biomass burning is a minor contributor to TC and has high contribution in winter. •Ratios of OC bio and OC bb to TC have a natural logarithmic relation with lev/OC bb . -- The contributions of OC bio and OC bb to TC have a natural logarithmic relationship with the levoglucosan/OC bb ratios

  6. Implications of CI therapy for Visual Deficit Training

    Directory of Open Access Journals (Sweden)

    Edward eTaub

    2014-10-01

    Full Text Available We address here the question of whether the techniques of CI therapy, a family of treatments that has been employed in the rehabilitation of movement and language after brain damage might apply to the rehabilitation of such visual deficits as unilateral spatial neglect and visual field deficits. CI therapy has been used successfully for the upper and lower extremities after chronic stroke, cerebral palsy (CP, multiple sclerosis (MS, other CNS degenerative conditions, resection of motor areas of the brain, focal hand dystonia, and aphasia. Treatments making use of similar methods have proven efficacious for amblyopia.The CI therapy approach consists of four major components: intensive training, training by shaping, a transfer package to facilitate the transfer of gains from the treatment setting to everyday activities, and strong discouragement of compensatory strategies.CI therapy is said to be effective because it overcomes learned nonuse, a learned inhibition of movement that follows injury to the CNS. In addition, CI therapy produces substantial increases in the grey matter of motor areas on both sides of the brain. We propose here that these mechanisms are examples of more general processes: learned nonuse being considered parallel to sensory nonuse following damage to sensory areas of the brain, with both having in common diminished neural connections (DNC in the nervous system as an underlying mechanism. CI therapy would achieve its therapeutic effect by strengthening the diminished neural connections. Use-dependent cortical reorganization is considered to be an example of the more general neuroplastic mechanism of brain structure repurposing (BSR. If the mechanisms involved in these broader categories are involved in each of the deficits being considered, then it may be the principles underlying efficacious treatment in each case may be similar. The lessons learned during CI therapy research might then prove useful for the treatment of

  7. Characteristics and sources of the fine carbonaceous aerosols in Haikou, China

    Science.gov (United States)

    Liu, Baoshuang; Zhang, Jiaying; Wang, Lu; Liang, Danni; Cheng, Yuan; Wu, Jianhui; Bi, Xiaohui; Feng, Yinchang; Zhang, Yufen; Yang, Haihang

    2018-01-01

    Ambient PM2.5 samples were collected from January to September 2015 in Haikou. The carbonaceous fractions included OC, EC, OC1, OC2, OC3, OC4, EC1, EC2, EC3, Char-EC (EC1 minus POC) and Soot-EC (EC2 plus EC3) were analysed in this study. The results indicate that the mean concentrations of OC and EC are 5.6 and 2.5 μg/m3 during the sampling period, respectively; and the concentrations of most of carbonaceous fractions are the highest in winter and the lowest in spring. The seasonal variations of Soot-EC and Char-EC concentrations show distinct differences. The concentrations of Char-EC are higher in winter and lower in spring; while those of Soot-EC are lower in winter and higher in summer. Compared to Char-EC, the concentrations of Soot-EC show smaller seasonal-variation in Haikou. The Char-EC has the higher correlations with OC and EC (r = 0.91 and 0.95, P 0.05). The average ratios of Char-EC/Soot-EC are in the order of winter (15.9) > autumn (4.9) > summer (4.0) > spring (3.6), with an average value of 7.1. According to error estimation (EE) diagnostics analysis, four factors are revealed in Positive Matrix Factorization (PMF) analysis during each season. The combined gasoline/diesel vehicle exhaust, coal combustion, biomass burning and specific diesel vehicle exhaust are identified as the major sources of carbonaceous aerosols, and their contributions during the whole year are up to 29.3%, 27.4%, 17.9% and 15.9%, respectively. The transport trajectories of the air masses illustrate distinct differences during different seasons, and the transport trajectories are mainly derived from the mainland China (i.e. Jiangxi, Fujian and Guangdong provinces) in winter, likely caused by higher contribution of coal combustion.

  8. Study of Carbonaceous Material in cherts from Barberton Greenstone Belt and the Astrobiological Implications.

    Science.gov (United States)

    Rull, F.; Venegas, G.; Montero, O.; Medina, J.

    2012-04-01

    Carbonaceous matter is present in chert deposits of Barberton Greenstone Belt (BGB), South Africa. This is a famous place in the world for its Archean geology, wich represents around 3.5 billion years of earth's history. Therefore this area provides us the opportunity to study and understand an important part history of our planet, and also allow to compare with the geological history of other planets in our solar system [1]. Raman micro-spectroscopy has proved to be a very important and non-destructive powerful tool for distinguish micro-sized particles of C-polymorphs, as it is very sensitive to the nature of carbon bonding [2]. The connection between the Raman characterization of these carbonaceous phases with ancient biogenic activity it's of special interest. Cherts of BGB have been interpreted as precipitates or diagenetic replacements of preexisting sedimentary and pyroclastic deposits in a silica saturated Archean ocean [3]. Several layered Samples of cherts from BGB utility for the present study were collected during the expedition carried out in August 2010 sponsored by CNES and ESA. A detailed Raman spectral analysis of carbon C-C vibrations has been performed in the first (1200-1800 cm-1) and second (2500-3200 cm-1) order regions [4]. The results show important changes in the G-D bands in the layered structure of chert. Additionally a UPLC-ESI-QTOF-MS was carried out trying to introduce new insight in the Raman interpretation of the bands and in the possible assignments to particular molecular groups which could be related with biotic or abiotic origin of the carbonaceous material. Among the tentative compounds obtained from UPLC-ESI-QTOF-MS study it is worth to mention hydroxy-lycopene and the hydroxyl derivative of β-carotene (i.e. β-cryptoxanthin), which are carotenoids produced by cyanobacteria. These results are consistent with the presence of 22-Hopanol and Tetrahymanol, which are characteristic hopanoids of photosynthetic cyanobacteria and have

  9. Global climate impacts of country-level primary carbonaceous aerosol from solid-fuel cookstove emissions

    International Nuclear Information System (INIS)

    Lacey, Forrest; Henze, Daven

    2015-01-01

    Cookstove use is globally one of the largest unregulated anthropogenic sources of primary carbonaceous aerosol. While reducing cookstove emissions through national-scale mitigation efforts has clear benefits for improving indoor and ambient air quality, and significant climate benefits from reduced green-house gas emissions, climate impacts associated with reductions to co-emitted black (BC) and organic carbonaceous aerosol are not well characterized. Here we attribute direct, indirect, semi-direct, and snow/ice albedo radiative forcing (RF) and associated global surface temperature changes to national-scale carbonaceous aerosol cookstove emissions. These results are made possible through the use of adjoint sensitivity modeling to relate direct RF and BC deposition to emissions. Semi- and indirect effects are included via global scaling factors, and bounds on these estimates are drawn from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. Absolute regional temperature potentials are used to estimate global surface temperature changes. Bounds are placed on these estimates, drawing from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. We estimate a range of 0.16 K warming to 0.28 K cooling with a central estimate of 0.06 K cooling from the removal of cookstove aerosol emissions. At the national emissions scale, countries’ impacts on global climate range from net warming (e.g., Mexico and Brazil) to net cooling, although the range of estimated impacts for all countries span zero given uncertainties in RF estimates and fuel characterization. We identify similarities and differences in the sets of countries with the highest emissions and largest cookstove temperature impacts (China, India, Nigeria, Pakistan, Bangladesh and Nepal), those with the largest temperature impact per carbon emitted (Kazakhstan, Estonia, and Mongolia), and those that would provide the

  10. Global climate impacts of country-level primary carbonaceous aerosol from solid-fuel cookstove emissions

    Science.gov (United States)

    Lacey, Forrest; Henze, Daven

    2015-11-01

    Cookstove use is globally one of the largest unregulated anthropogenic sources of primary carbonaceous aerosol. While reducing cookstove emissions through national-scale mitigation efforts has clear benefits for improving indoor and ambient air quality, and significant climate benefits from reduced green-house gas emissions, climate impacts associated with reductions to co-emitted black (BC) and organic carbonaceous aerosol are not well characterized. Here we attribute direct, indirect, semi-direct, and snow/ice albedo radiative forcing (RF) and associated global surface temperature changes to national-scale carbonaceous aerosol cookstove emissions. These results are made possible through the use of adjoint sensitivity modeling to relate direct RF and BC deposition to emissions. Semi- and indirect effects are included via global scaling factors, and bounds on these estimates are drawn from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. Absolute regional temperature potentials are used to estimate global surface temperature changes. Bounds are placed on these estimates, drawing from current literature ranges for aerosol RF along with a range of solid fuel emissions characterizations. We estimate a range of 0.16 K warming to 0.28 K cooling with a central estimate of 0.06 K cooling from the removal of cookstove aerosol emissions. At the national emissions scale, countries’ impacts on global climate range from net warming (e.g., Mexico and Brazil) to net cooling, although the range of estimated impacts for all countries span zero given uncertainties in RF estimates and fuel characterization. We identify similarities and differences in the sets of countries with the highest emissions and largest cookstove temperature impacts (China, India, Nigeria, Pakistan, Bangladesh and Nepal), those with the largest temperature impact per carbon emitted (Kazakhstan, Estonia, and Mongolia), and those that would provide the

  11. Source apportionment of carbonaceous aerosols over South and East Asia using dual carbon isotopes

    Science.gov (United States)

    Gustafsson, O.; Kirillova, E. N.; Andersson, A.-; Kruså, M.; Sheesley, R. J.; Tiwari, S.-; Lee, M.; Chen, B.; Du, K.

    2012-12-01

    Emissions of black carbon (BC) and other components of carbonaceous aerosols affect both climate and health in South and East Asia, yet substantial uncertainties exist regarding their sources. The relative contribution to atmospheric BC from fossil fuel versus biomass combustion is important to constrain both to direct mitigation and as their different properties make their effects on climate forcing and respiratory health different. This study approached the sourcing challenge by applying microscale radiocarbon measurements to aerosol particles collected in both source regions and at regional receptor observatories of both S Asia (New Delhi and the Maldives Climate Observatory) and of E Asia (Beijing, Shanghai, South China Coastal Observatory and the Korea Climate Observatory - Gosan, KCO-G, Jeju Island). The radiocarbon approach is ideally suited to this task as fossil sources are void of 14C whereas biomass combustion products hold a contemporary 14C signal. For S Asia, the 14C-based observations suggest that biomass combustion contributes half to two-thirds of the BC loading. In contrast, for E Asia, fossil fuel combustion account for four-fifths of the BC emitted from China. This source-diagnostic radiocarbon signal in the ambient aerosol over East Asia establishes a much larger role for fossil fuel combustion than suggested by all fifteen BC emission inventory models. There are also poor constraints on the sources of water-soluble organic carbon (WSOC), a large hydrophilic component of carbonaceous aerosols that enhances the propensity of aerosols to form clouds. In a 15-mo continuous campaign in S Asia, radiocarbon-based source apportionment of WSOC shows the dominance of biogenic/biomass combustion sources but also a substantial anthropogenic fossil-fuel contribution (about 20%). WSOC in E Asia reaching KCO-G were 50% from fossil sources. Aerosols reaching the Maldives after long-range over-ocean transport were enriched by 3-4‰ in δ13C-WSOC. This is

  12. Cinema, ciência e percepção.

    Directory of Open Access Journals (Sweden)

    Márcio Barreto

    Full Text Available Resumo O cinema invoca a questão dos limites da percepção humana, pois modula o tempo em imagens tão reais quanto artificiais, revelando algo mais próximo de uma nova dimensão da realidade do que de sua representação. No início do século XX, a ciência modifica o real percebido através das lentes dos microscópios e das teorias da física moderna; o parentesco entre cinema e ciência está principalmente naquilo que excede o campo perceptivo e é explorado neste artigo para mostrar como a tensão entre o caráter estático da fotografia e a fluidez fugitiva do tempo revela a ciência sem seus estereótipos habituais.

  13. Em torno do conceito de ciência

    OpenAIRE

    Fonseca, Maria de Jesus

    1996-01-01

    A comunicação que ora se apresenta surge no âmbito da iniciativa "VIVA A CIÊNCIA" - 1994, promovida pela Secretaria de Estado da Ciência e Tecnologia e já em 2º edição. São objectivos deste projecto a divulgação da ciência e da tecnologia tornando "visível a importância da ciência e da tecnologia numa sociedade que já se habituou aos seus benefícios, mas que ainda teme e se interroga sobre os seus efeitos futuros."1 Nesse sentido, pretende-se que esta semana constitua, a nível nacional, u...

  14. Using the Web for Competitive Intelligence (CI) Gathering

    Science.gov (United States)

    Rocker, JoAnne; Roncaglia, George

    2002-01-01

    Businesses use the Internet as a way to communicate company information as a way of engaging their customers. As the use of the Web for business transactions and advertising grows, so too, does the amount of useful information for practitioners of competitive intelligence (CI). CI is the legal and ethical practice of information gathering about competitors and the marketplace. Information sources like company webpages, online newspapers and news organizations, electronic journal articles and reports, and Internet search engines allow CI practitioners analyze company strengths and weaknesses for their customers. More company and marketplace information than ever is available on the Internet and a lot of it is free. Companies should view the Web not only as a business tool but also as a source of competitive intelligence. In a highly competitive marketplace can any organization afford to ignore information about the other players and customers in that same marketplace?

  15. A ideia de ciência em Karl Marx

    Directory of Open Access Journals (Sweden)

    Ricardo Luís Chaves Feijó

    2015-12-01

    ideias: a economia política clássica e o legado alemão. Em seguida, investiga-se o que seria a sua concepção particular de ciência, entendida como uma proposta de fundir esses dois legados. Avalia-se, em seguida, o caráter científico da contribuição marxiana, entendida como o fazer de uma ciência que se propõe positiva. Destarte, iremos examinar as razões que separam a tradição marxiana e o mainstream da economia atual, mostrando que a natureza peculiar de uma ciência de raízes alemãs gera dificuldades na comunicação entre uma e outra.

  16. The carbonaceous matter in the uraniferous dequartzified and albitized leucogranite of Saraya (Senegal): an example of superimposed hydrothermal alterations

    International Nuclear Information System (INIS)

    Mouthier, B.

    1988-01-01

    Two superimposed early hydrothermal alterations have been recognized in the Proterozoic Saraya leucogranite. Successively are described a major dequartzification leading to an episyenite infilled with carbonaceous matter and sulfate during an interruption of the system, succeeded by a mobilization of U and other elements during an albitization. A dolomite filling up followed by a silicopotassic feed-back alteration, close down the system [fr

  17. Observation of carbonaceous aerosols during 2006-2009 in Nyainqêntanglha Mountains and the implications for glaciers.

    Science.gov (United States)

    Zhao, Shuyu; Ming, Jing; Sun, Junying; Xiao, Cunde

    2013-08-01

    Atmospheric carbonaceous aerosols were sampled discontinuously from July 2006 to December 2009 at Nam Co Comprehensive Observation and Research Station (NCOS) in the central Tibetan Plateau (TP). The mean daily concentration of carbonaceous aerosols increased from 268 to 330 ng m(-3), and pollution episodes could significantly increase the mean level of carbonaceous aerosols in the total mass concentration. Organic carbon was the main component of carbonaceous aerosols at NCOS, and black carbon (BC) accounted for 5.8 %. Seven-day air masses backward trajectories calculated by the Hybrid Single-Particle Lagrangian Integrated Trajectory model and the aerosol optical depth distribution in the TP and South Asia both suggested that atmospheric pollutants emitted from Northern India and South Asia could penetrate into central TP by southwest winds. Due to the seasonal variations of emission sources and regional atmospheric conditions, calculated BC deposition flux in the nonmonsoon season was higher than that in the monsoon season. Increased BC concentration in snowpack in winter from 2007 to 2009 indicated that the atmospheric environment in central TP became more polluted and the influences from human activities have strengthened. Pollution episodes could significantly increase BC concentrations in the snowpack on a seasonal scale, which would furthermore affect the surface albedo.

  18. Nitrogen-doped one-dimensional (1D) macroporous carbonaceous nanotube arrays and their application in electrocatalytic oxygen reduction reactions

    Science.gov (United States)

    She, Xilin; Yang, Dongjiang; Jing, Dengwei; Yuan, Fang; Yang, Weiyou; Guo, Liejin; Che, Yanke

    2014-09-01

    A nitrogen(N)-doped one-dimensional (1D) macroporous carbonaceous nanotube array was fabricated by using an anodic alumina oxide (AAO) template. The large diameter of the nanotubes (~200 nm) could overcome the sluggish mass transfer phenomena in the common micro/mesoporous carbon-based electrodes. Combining the activation of the π electrons of the sp2 carbon array by N-doping, the novel 1D macroporous carbonaceous nanotube array exhibited high performance for the oxygen reduction reaction (ORR).A nitrogen(N)-doped one-dimensional (1D) macroporous carbonaceous nanotube array was fabricated by using an anodic alumina oxide (AAO) template. The large diameter of the nanotubes (~200 nm) could overcome the sluggish mass transfer phenomena in the common micro/mesoporous carbon-based electrodes. Combining the activation of the π electrons of the sp2 carbon array by N-doping, the novel 1D macroporous carbonaceous nanotube array exhibited high performance for the oxygen reduction reaction (ORR). Electronic supplementary information (ESI) available: Experimental section, XRD patterns, XPS spectra and electrochemical properties of carbon-based electrodes. See DOI: 10.1039/c4nr03340j

  19. Electro-desalination of sulfate contaminated carbonaceous sandstone – risk for salt induced decay during the process

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.

    2016-01-01

    Sodium-sulphate is known to cause severe stone damage. This paper is focused on removal of this salt from carbonaceous sandstone by electro-desalination (ED). The research questions are related to possible stone damage during ED and subsequently suction cycles are made in distilled water before...

  20. Earth-approaching asteroids: Populations, origin, and compositional types

    Science.gov (United States)

    Shoemaker, E. M.; Helin, E. F.

    1978-01-01

    Origin, physical properties, and discovery history of smaller asteroids are reviewed. They appear to link the main belt objects, namely the comets and meteorites. Physical observations suggest that a wide variety of compositional types are represented among the near-earth asteroids; the apparent rarity of carbonaceous objects is stated.

  1. [Inpatient rehabilitation of adult CI users: Results in dependency of duration of deafness, CI experience and age].

    Science.gov (United States)

    Zeh, R; Baumann, U

    2015-08-01

    Cochlear implants (CI) have proven to be a highly effective treatment for severe hearing loss or deafness. Inpatient rehabilitation therapy is frequently discussed as a means to increase the speech perception abilities achieved by CI. However, thus far there exists no quantitative evaluation of the effect of these therapies. A retrospective analysis of audiometric data obtained from 1355 CI users compared standardized and qualitative speech intelligibility tests conducted at two time points (admission to and discharge from inpatient hearing therapy, duration 3-5 weeks). The test battery comprised examination of vowel/consonant identification, the Freiburg numbers and monosyllabic test (65 and 80 dB sound pressure level, SPL, free-field sound level), the Hochmair-Schulz-Moser (HSM) sentence test in quiet and in noise (65 dB SPL speech level; 15 dB signal-to-noise ratio, SNR), and a speech tracking test with and without lip-reading. An average increase of 20 percentage points was scored at discharge compared to the admission tests. Patients of all ages and duration of deafness demonstrated the same amount of benefit from the rehabilitation treatment. After completion of inpatient rehabilitation treatment, patients with short duration of CI experience (below 4 months) achieved test scores comparable to experienced long-term users. The demonstrated benefit of the treatment was independent of age and duration of deafness or CI experience. The rehabilitative training program significantly improved hearing abilities and speech perception in CI users, thus promoting their professional and social inclusion. The present results support the efficacy of inpatient rehabilitation for CI recipients. Integration of this or similar therapeutic concepts in the German catalog of follow-up treatment measures appears justified.

  2. Nauczanie sprawności komunikacyjnych w grupach ekonomicznych

    OpenAIRE

    Wielkiewicz-Jałmużna, Dorota

    2013-01-01

    Celem nauczania języka polskiego w grupach ekonomicznych jest przede wszystkim rozwijanie kompetencji uczących się. Kluczowe znaczenie mają umiejętności receptywne czyli rozumienie ze słuchu i czytanie. Istotne znaczenie ma również nauczanie sprawności produktywnych to jest mówienia i pisania. Kolejnymi sprawnościami językowymi, które uczniowie zdobywają pod nadzorem nauczyciela są: umiejętność interakcji i mediacji.

  3. BADANIE OSŁONNOŚCI RADIACYJNEJ BETONÓW SPECJALNYCH

    Directory of Open Access Journals (Sweden)

    Agnieszka BURAKOWSKA

    2016-07-01

    Full Text Available W artykule przedstawiono wyniki badań właściwości osłonnych betonów eksperymentalnych przed promieniowaniem gamma, z wykorzystaniem zamkniętego źródła promieniotwórczego 137Cs. Do analiz sporządzono i opisano specjalne stanowisko badawcze o określonej geometrii. Do badań wykorzystano odpowiednio przygotowane próbki betonów ciężkich o zróżnicowanym składzie. W ramach prac przebadano piętnaście rodzajów betonów różniących się przede wszystkim zawartością kruszyw oraz gęstością objętościową. Na podstawie uzyskanych danych pomiarowych, dla poszczególnych prób betonów, otrzymano wartości grubości kolejnych warstw połówkowych (HVL i dziesięciochłonnych (TVL. Z przeprowadzonych analiz wynika, iż najlepsze parametry osłonne w polu promieniowania gamma dla izotopu 137Cs mają betony, z których kruszywem magnetytowym oraz barytowym. Betony te miały bardzo wysoką gęstość - powyżej 3300 kg/m3. Gorszymi parametrami charakteryzowały się natomiast mieszanki zawierające w składzie tylko kruszywa zwykłe (serpentynit lub amfibolit, a ich gęstość nie przekraczała 2450 kg/m3. Otrzymane wyniki badań, zgodnie z wcześniejszymi założeniami, wskazują, że wraz ze wzrostem gęstości materiału osłonowego warstwa HVL (odpowiednio TVL zmniejsza się, co oznacza, że właściwości osłonowe materiału przed promieniowaniem gamma ulegają poprawie

  4. CHARAKTERYSTYKA TRWAŁOŚCI ZMĘCZENIOWEJ RECYKLOWANEJ PODBUDOWY

    Directory of Open Access Journals (Sweden)

    Przemysław BUCZYŃSKI

    2016-07-01

    Full Text Available W artykule przedstawiono ocenę trwałości zmęczeniowej recyklowanej podbudowy wykonanej w technologii recyklingu głębokiego na zimno z emulsją asfaltową (MCE. W składzie recyklowanej podbudowy zastosowano trzy spoiwa tj. cement CEM I 32,5R, wapno hydratyzowane Ca(OH2 oraz mieszaninę cementu i wapna hydratyzowanego w proporcjach 50% CEM do 50% Ca(OH2. Udział spoiwa w mieszance recyklowanej podbudowy ustalono na 2,5%. Jako lepiszcze zastosowano kationową emulsję wolnorozpadową C60B10 ZM/R w ilości 3%. W celu określenia jakości recyklowanej podbudowy wykonano podstawowe badanie właściwości fizycznych oraz mechanicznych tj. zawartość wolnej przestrzeni Vm, wytrzymałość na pośrednie rozciąganie ITSDRY, odporność na działanie wody TSR oraz moduł sztywności w pośrednim rozciąganiu Sm w temperaturze 2OC, 10OC oraz 20OC. Ocenę trwałości zmęczeniowej recyklowanej podbudowy określono w teście pośredniego rozciągania (Indirect Tensil – Fatigue Test zgodnie z wymaganiami normy PN-EN 12697-26 zał. E. Badanie przeprowadzono w trybie kontrolowanego naprężenia tj. 250 kPa, 400 kPa oraz 500kPa. Badanie zmęczenia recyklowanej podbudowy pozwoliło określić wpływ rodzaju spoiwa na zmianę trwałości przy cyklicznym obciążeniu oraz zmiennym poziomie naprężenia. W oparciu o założenia planu badań możliwe było wytypowanie, spoiwa które zapewni uzyskanie wymaganej trwałości zmęczeniowej.

  5. APPLICATION OF ACROBATIC EXEerCI SES IN A HANDBALL TRAINING PROCESS

    Directory of Open Access Journals (Sweden)

    Radojica Marušić

    2007-05-01

    Full Text Available Ac ro bat exer ci ses re pre sent a ba se for ac qu i ring com plex hand ball exer ci sing techni qu es. Hand ball players get to know dif fe rent types of mo ving and put ting in mo tion dif fe rent parts of body. They ma ster the ba sic com po nents – di rec tion, speed, am pli tu de, in ten sity of ne u ro mu scu lar ten sion, and at the sa me ti me they le arn how to di rect the ir mo tion pre ci sely and how to co or di na te the ir mo ves in spa ce and ti me.

  6. Reaction between Steel-Making Slag and Carbonaceous Materials While Mixing with High Density Polyethylene

    Science.gov (United States)

    Hong, Lan; Sahajwalla, Veena

    2016-01-01

    Since the beginning of the extensive applications in numerous high temperature processes such as iron- and steel-making, coke-making etc. partly in the place of coke, the investigation into the reaction mechanism of waste plastics has become increasingly necessary. In this paper a fundamental study on the behavior of a typical component of waste plastics, high density polyethylene (HDPE), in a mixture with coke at a 1:1 ratio in mass base was conducted during the reaction with iron oxide in steel-making slag at 1823 K and was compared with coke and graphite. The reaction mechanism of carbonaceous materials was analyzed based on the contents of CO and CO2 in the off-gas monitored by an infrared (IR) gas analyzer. It is clear from the results that the reaction of HDPE and coke mixture with steel-making slag approached equilibrium of the Boudouard reaction more quickly and closely than coke or graphite.

  7. Influence of hydrothermal carbonization and treatment by microwave on morphology of carbonaceous materials obtained from lignin

    International Nuclear Information System (INIS)

    Oliveira, I.B.; Barin, G.B.; Barreto, L.S.; Santos, M.C.G.

    2014-01-01

    The conversion of biomass into carbon materials with special morphologies via hydrothermal carbonization presents itself as a potential route for the use of renewable precursors in obtaining carbonaceous structures. In the present study the influence of the hydrothermal carbonization (250 ° C / 4 h) followed by microwave treatment (1-2-4 hours at 25 and 40 mL) in morphology and structure of lignin. The samples were analyzed by X-ray diffraction and scanning electron microscopy. The plaque morphology of lignin was preserved during the hydrothermal process. However, when treated by microwave can be observed partial dissolution of lignin leading to the formation of microspheres on the surface. XRD presence of an amorphous halo 2θ = 23 ° attributed to the (002) network of the amorphous carbon was observed. (author)

  8. Carbowaste: treatment and disposal of irradiated graphite and other carbonaceous waste

    International Nuclear Information System (INIS)

    Von Lensa, W.; Rizzato, C.; Baginski, K.; Banford, A.W.; Bradbury, D.; Goodwin, J.; Grambow, B.; Grave, M.J.; Jones, A.N.; Laurent, G.; Pina, G.; Vulpius, D.

    2014-01-01

    The European Project on 'Treatment and Disposal of Irradiated Graphite and other Carbonaceous Waste (CARBOWASTE)' addressed the retrieval, characterization, treatment, reuse and disposal of irradiated graphite with the following main results: - I-graphite waste features significantly depend on the specific manufacture process, on the operational conditions in the nuclear reactor (neutron dose, atmosphere, temperature etc.) and on radiolytic oxidation leading to partial releases of activation products and precursors during operation. - The neutron activation process generates significant recoil energies breaking pre-existing chemical bonds resulting in dislocations of activation products and new chemical compounds. - Most activation products exist in different chemical forms and at different locations. - I-graphite can be partly purified by thermal and chemical treatment processes leaving more leach-resistant waste products. - Leach tests and preliminary performance analyses show that i-graphite can be safely disposed of in a wide range of disposal systems, after appropriate treatment and/or conditioning. (authors)

  9. Biomass-Derived Porous Carbonaceous Aerogel as Sorbent for Oil-Spill Remediation.

    Science.gov (United States)

    Wang, Zhuqing; Jin, Pengxiang; Wang, Min; Wu, Genhua; Dong, Chen; Wu, Aiguo

    2016-12-07

    We prepared a cost-effective, environmentally friendly carbonaceuous oil sorbent with a lotus effect structure using a simple one-pot hydrothermal reaction and a mild modification process. The carbonaceous oil sorbent can rapidly, efficiently, and continuously collect oil in situ from a water surface. This sorbent was unlike traditional sorbents because it was not dependent on the weight and volume of the sorption material. The sorbent was also successfully used to separate and collect crude oil from the water surface and can collect organic solvents underwater. This novel oil sorbent and oil-collection device can be used in case of emergency for organic solvent leakages, as well as leakages in tankers and offshore drilling platforms.

  10. Filaments in Carbonaceous Meteorites: Mineral Crystals, Modern Bio-Contaminants or Indigenous Microfossils of Trichomic Prokaryotes?

    Science.gov (United States)

    Hoover, Richard B.; Borisyak, A. A.

    2011-01-01

    Environmental (ESEM) and Field Emission Scanning Electron Microscopy (FESEM) investigations have resulted in the detection of a large number of complex filaments in a variety of carbonaceous meteorites. Many of the filaments were observed to be clearly embedded the rock matrix of freshly fractured interior surfaces of the meteorites. The high resolution images obtained combined with tilt and rotation of the stage provide 3-dimensional morphological and morphometric data for the filaments. Calibrated Energy Dispersive X-ray Spectroscopy (EDS) and 2-D elemental X-ray maps have provided information on the chemical compositions of the filaments and the minerals of the associated meteorite rock matrix. These observations are used to evaluate diverse hypotheses regarding the possible abiotic or biogenic nature of the filaments found embedded in these meteorites.

  11. A unifying model for Neoproterozoic-Palaeozoic exceptional fossil preservation through pyritization and carbonaceous compression.

    Science.gov (United States)

    Schiffbauer, James D; Xiao, Shuhai; Cai, Yaoping; Wallace, Adam F; Hua, Hong; Hunter, Jerry; Xu, Huifang; Peng, Yongbo; Kaufman, Alan J

    2014-12-17

    Soft-tissue fossils capture exquisite biological detail and provide our clearest views onto the rise of animals across the Ediacaran-Cambrian transition. The processes contributing to fossilization of soft tissues, however, have long been a subject of debate. The Ediacaran Gaojiashan biota displays soft-tissue preservational styles ranging from pervasive pyritization to carbonaceous compression, and thus provides an excellent opportunity to dissect the relationships between these taphonomic pathways. Here geochemical analyses of the Gaojiashan fossil Conotubus hemiannulatus show that pyrite precipitation was fuelled by the degradation of labile tissues through bacterial sulfate reduction (BSR). Pyritization initiated with nucleation on recalcitrant tube walls, proceeded centripetally, decelerated with exhaustion of labile tissues and possibly continued beneath the BSR zone. We propose that pyritization and kerogenization are regulated principally by placement and duration of the decaying organism in different microbial zones of the sediment column, which hinge on post-burial sedimentation rate and/or microbial zone thickness.

  12. Comparison of Ablation Predictions for Carbonaceous Materials Using CEA and JANAF-Based Species Thermodynamics

    Science.gov (United States)

    Milos, Frank S.

    2011-01-01

    In most previous work at NASA Ames Research Center, ablation predictions for carbonaceous materials were obtained using a species thermodynamics database developed by Aerotherm Corporation. This database is derived mostly from the JANAF thermochemical tables. However, the CEA thermodynamics database, also used by NASA, is considered more up to date. In this work, the FIAT code was modified to use CEA-based curve fits for species thermodynamics, then analyses using both the JANAF and CEA thermodynamics were performed for carbon and carbon phenolic materials over a range of test conditions. The ablation predictions are comparable at lower heat fluxes where the dominant mechanism is carbon oxidation. However, the predictions begin to diverge in the sublimation regime, with the CEA model predicting lower recession. The disagreement is more significant for carbon phenolic than for carbon, and this difference is attributed to hydrocarbon species that may contribute to the ablation rate.

  13. Quantification of the carbonaceous matter origin in submicron marine aerosol particles by dual carbon isotope analysis

    Science.gov (United States)

    Ceburnis, D.; Garbaras, A.; Szidat, S.; Rinaldi, M.; Fahrni, S.; Perron, N.; Wacker, L.; Leinert, S.; Remeikis, V.; Facchini, M. C.; Prevot, A. S. H.; Jennings, S. G.; O'Dowd, C. D.

    2011-01-01

    Dual carbon isotope analysis has been performed for the first time demonstrating a potential in organic matter apportionment between three principal sources: marine, terrestrial (non-fossil) and fossil fuel due to unique isotopic signatures. The results presented here, utilising combinations of dual carbon isotope analysis, provides a conclusive evidence of a dominant biogenic organic fraction to organic aerosol over biologically active oceans. In particular, the NE Atlantic, which is also subjected to notable anthropogenic influences via pollution transport processes, was found to contain 80% organic aerosol matter of biogenic origin directly linked to plankton emissions. The remaining carbonaceous aerosol was of fossil-fuel origin. By contrast, for polluted air advecting out from Europe into the NE Atlantic, the source apportionment is 30% marine biogenic, 40% fossil fuel, and 30% continental non-fossil fuel. The dominant marine organic aerosol source in the atmosphere has significant implications for climate change feedback processes.

  14. Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol

    DEFF Research Database (Denmark)

    Brown, Margaret E.; Mukhopadhyay, Aindrila; Keasling, Jay D.

    2016-01-01

    conversion with a key reaction performed by the acetone carboxylase complex (ACX). We engineered the heterologous expression of the ACX complex from Xanthobacter autotrophicus PY2 to match the naturally occurring subunit stoichiometry and purified the recombinant complex from E. coli for biochemical analysis....... Incorporating this ACX complex and enzymes from diverse organisms, we introduced an isopropanol degradation pathway in E. coli, optimized induction conditions, and decoupled enzyme expression to probe pathway bottlenecks. Our engineered E. coli consumed 65% of isopropanol compared to no-cell controls......We report an engineered strain of Escherichia coli that catabolizes the carbonaceous component of the extremely toxic chemical warfare agent sarin. Enzymatic decomposition of sarin generates isopropanol waste that, with this engineered strain, is then transformed into acetyl-CoA by enzymatic...

  15. Structural characteristics of internally mixed carbonaceous aggregates from Barcelona (Spain) during DAURE winter campaign

    Science.gov (United States)

    Coz, Esther; Casuccio, Gary S.; Robinson, Allen L.; Moreno, Teresa; Mohr, Claudia; Prevot, Andre S. H.; Artíñano, Begoña.

    2010-05-01

    Particle structure, understood as the characterization of size, morphology, texture and the spatial distribution of the different compounds at an individual particle level, influences carbonaceous aggregates behavior in the atmosphere and the respiratory system. Additionally, the absorption and scattering of light is modified by the particle structure and also influences water absorption and water vapor nucleation and, hence cloud formation, residence time in the atmosphere and removal processes. Two factors seem determinant in these processes: quantity of scattering material adsorbed onto the light absorbing core during the residence in the atmosphere and subsequent aging, and the spatial distribution of this condensed matter (commonly discussed as internally/externally mixtures). Morning, noon, afternoon, and evening samples were collected for electron microscopy analyses during 3 consecutive days during an atmospheric episode of thermal inversion in February 2009 in an urban background area within the city of Barcelona. The main goal of this study was to quantify the variations in morphology and state of mixture of carbonaceous soot-like aggregate structures observed during different times of the day. The study was part of the winter campaign: "Determination of the sources of atmospheric Aerosols in Urban and Rural Environments in the western Mediterranean" (DAURE, February/March 2009). The analysis of the aggregate structure was conducted by digital image analysis of several thousand particles to determine variations on size, shape and texture by means of several different mathematical descriptors such as aspect ratio/elongation, compactness and roughness through fractal dimension analysis, textural energy and entropy. Results indicate that carbon aggregates were mostly within 200-400 nm of geometric size, with slightly smaller sizes during time intervals associated to traffic peaks compared to the daily average. The morphological parameters obtained for these

  16. Nitrogen-Doped Carbonaceous Materials for Removal of Phenol from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Magdalena Hofman

    2012-01-01

    Full Text Available Carbonaceous material (brown coal modified by pyrolysis, activation, and enrichment in nitrogen, with two different factor reagents, have been used as adsorbent of phenol from liquid phase. Changes in the phenol content in the test solutions were monitored after subsequent intervals of adsorption with selected adsorbents prepared from organic materials. Significant effect of nitrogen present in the adsorbent material on its adsorption capacity was noted. Sorption capacity of these selected materials was found to depend on the time of use, their surface area, and pore distribution. A conformation to the most well-known adsorption isotherm models, Langmuir, and Freundlich ones, confirms the formation of mono- and heterolayer solute (phenol coverage on the surface of the adsorbent applied herein. The materials proposed as adsorbents of the aqueous solution contaminants were proved effective, which means that the waste materials considered are promising activated carbon precursors for liquid phase adsorbents for the environmental protection.

  17. Laboratory Studies of the Formation of Carbonaceous Cosmic Dust from PAH Precursors

    Science.gov (United States)

    Salama, Farid; Contreras, C. S.

    2012-05-01

    The study of the formation and destruction processes of cosmic dust is essential to understand and to quantify the budget of extraterrestrial organic molecules. Although dust with all its components plays an important role in the evolution of interstellar chemistry and in the formation of organic molecules, little is known on the formation and destruction processes of carbonaceous dust. PAHs are important chemical building blocks of interstellar dust. They are detected in interplanetary dust particles and in meteoritic samples and are an important, ubiquitous component of the interstellar medium. The formation of PAHs from smaller molecules has not been extensively studied. Therefore, it is imperative that laboratory experiments be conducted to study the dynamic processes of carbon grain formation from PAH precursors. Studies of interstellar dust analogs formed from a variety of PAH and hydrocarbon precursors as well as species that include O, N, and S, have recently been performed using the COSmIC facility in our laboratory under conditions that simulate interstellar and circumstellar environments. The species formed in the pulsed discharge nozzle (PDN) plasma source are detected and characterized with high-sensitivity cavity ringdown spectroscopy coupled to a Reflectron time-of-flight mass spectrometer (ReTOF-MS), thus providing both spectroscopic and ion mass information in-situ. We report the measurements obtained in these experiments. Studies with hydrocarbon precursors show the feasibility of specific molecules to form PAHs, while studies with carbon ring systems (benzene and derivatives, PAHs) precursors provide information on pathways toward larger carbonaceous molecules. From these unique measurements, we derive information on the size and the structure of interstellar dust grain particles, the growth and the destruction processes of interstellar dust and the resulting budget of extraterrestrial organic molecules. Acknowledgements: This research is

  18. Comunidades em processos formativos de professores de ciências

    Directory of Open Access Journals (Sweden)

    Willian Rubira da Silva

    2017-12-01

    Full Text Available Apresentamos compreensões sobre as diferentes concepções de comunidade dentro do contexto da formação de professores de Ciências. Termos relacionados a comunidades no contexto de ensino e aprendizagem vem se tornando genéricos, dificultando compreensões de trabalhos da área no Brasil. Visualizamos a necessidade de significar concepções do termo em questão no contexto da sociologia e psicologia para então avançar nas compreensões mais abrangentes dentro da educação. Ampliamos o estudo com uma revisão dos trabalhos publicados nos anais do Encontro Nacional de Pesquisa em Educação em Ciências correlacionando a formação de professores com as perspectivas teórico-práticas de comunidades em contexto educacional. Escolhemos os anais deste evento por ser um ponto de debate entre os pesquisadores na área de Educação em Ciências e que, desta maneira, nos possibilitou sistematizar diferentes concepções de comunidades. Essas foram agrupadas em 7 categorias emergentes distintas por aspectos teórico-práticos utilizados nos processos formativos de professores de Ciências.

  19. Ceux-ci ne sont pas : [luuletused] / Kalju Kruusa

    Index Scriptorium Estoniae

    Kruusa, Kalju, pseud., 1973-

    2003-01-01

    Sisu: Ceux-ci ne sont pas ; Köögivahet ; "Taara..." ; "Pakane pistab pisikesi ..." ; "Meri on kaet mattklaasiga ; Pydemise päivil ; "Toas muusika mängib ..." ; "Jäin juustu imetlema ; "Mu elu on mustikas ..." ; Hingepidetus ; ŁNo me gusta la cocina

  20. Uwarunkowania skuteczności działania inkubatorów przedsiębiorczości

    OpenAIRE

    Świeszczak, Krzysztof

    2016-01-01

    Skłonność społeczeństwa do prowadzenia własnej działalności gospodarczej odgrywa istotną rolę w rozwoju krajowych gospodarek. Biorąc pod uwagę charakterystykę jednostek należących do sektora MSP, ich potrzeby oraz bariery, niekiedy uniemożliwiające egzystencję na rynku, warto zwrócić uwagę na konieczność kreowania narzędzi wspomagających przedsiębiorczość. Spośród licznych instrumentów wsparcia jednostek z sektora MSP na szczególną uwagę zasługują inkubatory przedsiębiorczości , których dział...

  1. BIOGRAMY POLSKICH MYŚLICIELI RACHUNKOWOŚCI

    Directory of Open Access Journals (Sweden)

    Renata Biadacz

    2009-09-01

    Full Text Available Fragmenty artykułu: Włodzimierz Brzezin (1926–2008, profesor zwyczajny, doktor habilitowany, urodził się 1 lipca 1926 r. w Wieluniu, zmarł 29 grudnia 2008 r. w Częstochowie. (... Bilans działalności i osiągnięć Profesora Brzezina jest bardzo bogaty i trudno go przedstawić w skrócie. Należy jednak zaznaczyć, że jedną z cech charakteryzujących całokształt Jego zainteresowań naukowych jest szeroki krąg tematyczny. Obejmuje zagadnienia teoretyczne i praktyczne rachunkowości, zarówno sensu stricte, jak i sensu largo, jak również problematykę teorii pomiaru, analizy finansowej, controllingu, polityki bilansowej, wykorzystania rachunku kosztów przez kadrę inżynierską. Zdzisław Kołaczyk (1927–2008 docent doktor, urodził się 15 czerwca 1927 r. w Częstochowie, zmarł 9 lipca 2008 r. w Poznaniu. (... Działalność naukowa doc. dr Z. Kołaczyka skupiała się głównie na rachunkowości finansowej. Początkowo Jego zainteresowania naukowe koncentrowały się na rachunku kosztów przedsiębiorstw przemysłowych i budowlanych. Z tego zakresu opublikował kilka interesujących artykułów naukowych, zamieszczonych w Ruchu Prawniczym, Ekonomicznym i Socjologicznym oraz w Zeszytach Naukowych WSE w Poznaniu. W kolejnych latach doc. dra Z. Kołaczyka interesował rozwój rachunkowości jako nauki i działalności praktycznej

  2. Surviving High-temperature Components in CI Chondrites

    Science.gov (United States)

    Zolensky, M.; Frank, D.

    2014-01-01

    The CI1 chondrites, while having the most solar-like compo-sition of any astromaterial available for laboratory analysis, have also been considerably altered by asteroidal processes including aqueous alteration. It is of fundamental importance to determine their pre-alteration mineralogy, so that the state of matter in the early Solar System can be better determined. In the course of a re-examination of the compositional range of olivine and low-Ca pyroxene in CI chondrites Orgueil, Ivuna and Alais [1] we found the first reported complete CAI, as already reported [2], with at-tached rock consisting mainly of olivine and low-Ca pyroxene. The range of residual olivine major element compositions we have determined in the CIs (Fig. 1) may now be directly com-pared with those of other astromaterials, including Wild 2 grains. The abundance of olivine and low-Ca pyroxene in CIs is higher than is generally appreciated, and in fact much higher than for some CMs [1]. We also noted numerous rounded objects varying in shape from spheres to oblate spheroids, and ranging up to 100µm in size (Fig. 2), which have been previously noted [3] but have not been well documented or appreciated. We characterized the mineralogy by transmission electron microscopy and found that they consist mainly of rather fine-grained, flaky single phase to intergrown serpentine and saponite. These two materials in fact dominate the bulk of the host CI1 chondrites. With the exception of sparse spinels, the rounded phyllosilicate objects are remarka-bly free of other minerals, suggesting that the precursor from which the phyllosilicates were derived was a homogeneous mate-rial. We suggest that these round phyllosilicates aggregates in CI1 chondrites were cryptocrystalline to glassy microchondrules. If so then CI chondrites cannot be considered chondrule-free. Small though they are, the abundance of these putative microchondrules is the same as that of chondrules in the Tagish Lake meteorite.

  3. From hearing with a cochlear implant and a contralateral hearing aid (CI/HA) to hearing with two cochlear implants (CI/CI): a within-subject design comparison.

    Science.gov (United States)

    Luntz, Michal; Egra-Dagan, Dana; Attias, Joseph; Yehudai, Noam; Most, Tova; Shpak, Talma

    2014-12-01

    To compare within-subject bilateral-binaural and bimodal complementary abilities between bimodal (cochlear implant and hearing aid; CI/HA) and bilateral CI hearing (CI/CI), thereby enabling better-informed counseling of experienced CI/HA users contemplating contralateral implantation. Comparative within-subject case review. Outpatient hearing clinic. Ten experienced adult CI/HA users with severe-to-profound hearing loss in the HA ear, who converted to CI/CI between 2 and 11 years after initial implantation. Task-specific testing of bilateral-binaural hearing (sound lateralization, binaural summation/redundancy/unmasking, head-shadow effect), bimodal complementary benefit (contribution of low-frequency information), and a self-report Speech, Spatial, and Qualities of Hearing (SSQ) questionnaire, all before and 1 year after contralateral cochlear implantation. Test result differences between CI/HA and CI/CI conditions. CI/CI hearing was better than CI/HA for speech lateralization and for perception of semantically unpredictable sentences in speech noise with speech at 0 degrees and noise at +90 degrees azimuth on the old CI side. CI/HA was better than CI/CI only for differences between perception of natural prosody speech and of speech with flattened fundamental frequency (F0) contour with speech and noise in front (at 0 degrees azimuth). Total scores on the SSQ questionnaire were higher in CI/CI than in CI/HA users. Counseling regarding contralateral implantation for CI/HA users with severe-to-profound hearing loss in the HA ear, though generally positive, should consider individual functional needs, and cover expectations about the expected trade-off between gaining improved understanding and speech lateralization in challenging listening conditions and losing some low-frequency cues still available with CI/HA hearing.

  4. Perspektywy rozwojurachunkowości międzynarodowej

    Directory of Open Access Journals (Sweden)

    Stanisława T. Surdykowska

    2010-05-01

    Full Text Available Jednym z najbardziej niepokojących zjawisk, obserwowanych w procesie przygo-towywania sprawozdań finansowych, jest stale rosnąca tendencja do posługiwania się wąsko zdefiniowanymi regułami tego pomiaru, niekoniecznie uwzględniającymi istotę mierzonych kategorii. Organy ustalające standardy podejmują próby związane ze spełnieniem tych oczekiwań, lecz nie ma i nigdy nie będzie możliwości ustalania tak szczegółowych reguł, które mogłyby zostać wykorzystane w każdym pojedyn-czym elemencie pomiaru, o którym mowa. Ponadto istnieje wiele przykładów, które potwierdzają, że bardziej szczegółowe reguły, w porównaniu do raczej ogólnej zasady dotyczącej tego samego przedmiotu pomiaru, nie wyeliminowały, a nawet nie zmniej-szyły możliwości zarówno nieświadomych, jak i celowych/przestępczych zniekształ-ceń tego pomiaru. Wynika z tego konieczność krytycznego spojrzenia na standardy, które niezależnie od ich szczegółowości, tworzą iluzję precyzji w pomiarze dokonywanym w rachun-kowości, podczas gdy w swojej istocie pomiar ten jest zdeterminowany przez su-biektywne wybory osób w nim uczestniczących. W tym kontekście pojawia się py-tanie, czy aby te szczegółowe reguły pomiaru nie zwiększyły skłonności do nadużyć, zamiast je ograniczać. Pytania te są stawiane szczególnie często w przypadku po-jawiających się z coraz większą częstotliwością kryzysów finansowych. Jednocześnie IASB będąc w przyszłości globalną instytucją ustalającą standar-dy zakłada, że modyfikowane i ustalane przez nią standardy będą interpretowane zgodnie z „duchem”, a nie, jak dotychczas – zgodnie z „literą prawa”. Przedmiotem rozważań zawartych w referacie są sprzeczności i dylematy związane z takim sta-nowiskiem IASB.

  5. Perspectivas Interdisciplinaridades e Linguagem nas Ciências Humanas

    Directory of Open Access Journals (Sweden)

    Alzira Lobo de Arruda Campos

    2015-01-01

    Full Text Available As ciências humanas discutiram a questão da interdisciplinaridade ao longo do século XX. Mas, já no século anterior, figuras notáveis, como Wilhelm Dilthey e Karl Marx, questionavam-se sobre os paradigmas monistas da explicação e da compreensão. Interrogação reproduzida, entre muitos, por Sigmund Freud, Max Weber, Claude Lévi-Strauss, Fernand Braudel, Michel Serres. Em Educação, o grupo de Doutorado em Ciências da Educação, de Paris VIII, há 30 anos adotou a multirreferencialidade como metodologia hegemônica.

  6. Preparation of 1 Ci of europium 155 without carrier

    International Nuclear Information System (INIS)

    Falconi, N.; Radicella, R.

    1968-01-01

    High activity 'point' sources of 155 Eu are used for medical and industrial applications. For this purpose we have studied a method of obtaining I Ci of carrier free 155 Eu, with a solid residue smaller than 5 mg per Ci. In order to separate the 155 Eu from several grams of a 154 Sm enriched target we propose a procedure which is based on the work of Bouissieres and David, Onstott, and Takekoshi et al. The separation is carried out by electrolysis on a mercury cathode followed by purification on ion exchange resin. The yields of the europium separation and target recovery are 80 per cent and 90 per cent respectively. The time required for the procedure is three days. (authors) [fr

  7. O lazer como objeto das ciências humanas

    OpenAIRE

    de Almeida, Marco Antonio Bettine; Gutierrez, Gustavo Luis

    2008-01-01

    Resumo: Este artigo estudará o lazer moderno como objeto das ciências humanas, discutindo a influência do capitalismo na sua gênese e a necessidade de uma consciência coletiva do tempo livre para a sua formação. O discurso lógico científico Popperiano foi utilizado para dar unidade nas diferentes leituras e possibilitar o conflito, através da seguinte ferramenta metodológica, a constante construção interpretativa da ciência do objeto. Através destes parâmetros foi-nos possível analisar a impo...

  8. Structural Biology of CI from Phage TP901-1

    DEFF Research Database (Denmark)

    Rasmussen, Kim Krighaar

    ), three Operator sites, Right, Left and Distance (OR, OL and OD) and two Promoters, Right and Left (PR and PL). The CI repressor is generally the major regulator of temperate bacteriophages genetic switches. In general CI repressors consist of two domains, the N-Terminal Domain (NTD) and C-Terminal Domain......Viruses constitute the most abundant genetic pool on earth and are divided into several orders. One orders is the bacteriophages. A common characteristic of this order is the ability to infect bacteria. The order is further divided into families, subfamilies, genuses and species. Some species...... the interaction with DNA by crystallography and NMR. The binding are found to be similar to previously found pattern of HTH motifs DNA binding supporting the assumption that NTD is a HTH motif. The HTH motif itself revealed an extended scaffold helix, which we hypothesize might be an interaction site...

  9. Ciência e modernidade: a perspectiva dos movimentos sociais

    Directory of Open Access Journals (Sweden)

    Paulo Bassani

    2004-12-01

    Full Text Available Pensar alguns elementos que fazem parte da dinâmica e dos processos existentes nos movimentos sociais dos anos 90 é um dos objetivos centrais do trabalho. A valorização dos componentes micro sociais, subjetivos e do senso comum, coloca às Ciências Sociais, um desafio instigante, de aproximar a reflexão teórica com o que ocorre no plano do cotidiano.

  10. Unit test automation with Jenkins-CI tool

    OpenAIRE

    Ahmed, Anastasia

    2015-01-01

    Continuous Integration (CI) the process that is performing tasks continuously itself. Software development and its testing started a new era, which allows making the process productive and faster. It has been one of the fast growing industries in many parts of businesses. By the years devel-opment techniques has been improving and produced a quality product to the client in a shorter period. The competition raised, but expense of the production got smaller. Automation testing is a tes...

  11. O Jornal Nacional e a Ciência

    Directory of Open Access Journals (Sweden)

    Diego Andres Salcedo

    2009-10-01

    Full Text Available Entendendo a informação científica como aquela capaz de contribuir para o desenvolvimento de uma cultura científica, analisamos neste trabalho aspectos relacionados à presença da informação sobre ciência no Jornal Nacional (JN, da Rede Globo de Televisão. A partir da observação do noticiário veiculado de 1º de janeiro a 31 de março de 2007, foi possível identificar 88 matérias que traziam informações relacionadas à ciência. O corpus nos permitiu categorizar os tipos de inserção da ciência no JN, esboçar o interesse do JN pelos temas científicos e discutir seu papel na formação de uma cultura científica do povo brasileiro.

  12. Skinner: sobre ciência e comportamento humano

    Directory of Open Access Journals (Sweden)

    Angelo Augusto Silva Sampaio

    Full Text Available Atualmente, não se pode pensar no estudo do comportamento humano sem considerar a abordagem científica a este objeto: o campo da Psicologia científica. Esse campo é disputado por diversos enfoques teóricos que divergem quanto ao modo como definem ciência e comportamento humano. A abordagem de B. F. Skinner foi bastante proeminente no século XX, mas ainda continua a ser mal-entendida. Partindo do desenvolvimento histórico de sua obra, o presente texto visa a iluminar alguns aspectos relacionados às noções de ciência e comportamento humano desse autor e ressaltar as transformações por que passaram. Analisam-se três tópicos da obra de Skinner: seu período inicial (de 1930 a cerca de 1938, a obra "Ciência e Comportamento Humano" de 1953, e as influências da Biologia. São enfatizados aspectos relevantes da sua teorização sobre o tema: busca por relações funcionais, ênfase nos dados empíricos, operacionismo, externalismo, multideterminação do comportamento, experimentalismo, previsão e controle, ética.

  13. Causas e leis nas ciências do homem

    Directory of Open Access Journals (Sweden)

    Sara Albieri

    2011-12-01

    Full Text Available A proposta humeana acerca do método e da investigação na ciência do homem tornou-o um precursor do conhecido modelo covering-law de explicação científica, tal como defendido por Hempel, Nagel e outros filósofos contemporâneos da ciência. A interpretação da teoria da ciência de Hume como precursora desse modelo costuma ser majoritária entre os comentadores de sua filosofia. Apenas Donald Livingston travou uma discussão singular contra essa quase unanimidade, propondo-se a defender a existência de dois modelos de explicação na epistemologia de Hume, um adequado às ciências naturais, outro às morais. O autor apóia-se em certas passagens em que Hume parece reconhecer que, em ciências morais, predominariam as explicações recorrendo a causas morais, as quais consistiriam nas razões do agente ou conjunto de agentes envolvidos no evento a ser explicado. Defendemos que a diversidade das explicações causais naturais e morais em Hume pode ser discutida, não a partir de uma distinção radical de natureza, como aquela que Livingston quer estabelecer, mas a partir de uma distinção de grau: os graus de certeza que distinguem entre provas e probabilidades, entre explicações pela via dedutiva a partir de leis ou por generalizações estatísticas. Isto é, mais de acordo com a assimetria que Nagel reconhece entre ciências do particular e generalizadoras, quanto ao objetivo de estabelecer leis, no segundo caso, ou de apenas aplicá-las, no primeiro. Uma distinção compatível com aquela que Hume já adotara, atribuindo graus diferentes de generalidade de modo análogo a ciências naturais ou morais.Hume's proposal of a science of man is often taken as a precursor of the now well-known covering-law model of scientific explanation, sustained by Hempel, Nagel and other contemporary philosophers of science. Among Hume's commentators D. Livingston is an exception, defending the existence of two models of explanation in Hume

  14. I-Xe dating of aqueous alteration in the CI chondrite Orgueil: I. Magnetite and ferromagnetic separates

    Science.gov (United States)

    Pravdivtseva, O.; Krot, A. N.; Hohenberg, C. M.

    2018-04-01

    The I-Xe system was studied in a ferromagnetic sample separated from the Orgueil CI carbonaceous chondrite with a hand-held magnet and in two magnetite samples, one chemically separated before and the other one after neutron irradiation. This work was done in order to investigate the effects of chemical separation by LiCl and NaOH on the I-Xe system in magnetite. Our test demonstrated that the chemical separation of magnetite before irradiation using either LiCl or NaOH, or both, does not contaminate the sample with iodine and thus cannot lead to erroneous I-Xe ages due to introduction of uncorrelated 128∗Xe. The I-Xe ages of two Orgueil magnetite samples are mutually consistent within experimental uncertainties and, when normalized to an absolute time scale with the reevaluated Shallowater aubrite standard, place the onset of aqueous alteration on the CI parent body at 4564.3 ± 0.3 Ma, 2.9 ± 0.3 Ma after formation of the CV Ca-AI-rich inclusions (CAIs). The I-Xe age of the ferromagnetic Orgueil separate is 3.4 Ma younger, corresponding to a closure of the I-Xe system at 4560.9 ± 0.2 Ma. These and previously published I-Xe data for Orgueil (Hohenberg et al., 2000) indicate that aqueous alteration on the CI parent body lasted for at least 5 Ma. Although the two magnetite samples gave indistinguishable I-Xe ages, their temperature release profiles differed. One of the two Orgueil magnetites released less radiogenic Xe than the other, 80% of it corresponding to the low-temperature peak of the release profile, compared to only 6% in case of the second Orgueil magnetite sample. This could be due to the difference in iodine trapping efficiencies for magnetite grains of different morphologies. Alternatively, the magnetite grains with the lower radiogenic Xe concentrations may have formed at a later stage of alteration when iodine in an aqueous solution was depleted.

  15. Porous nitrogen-enriched carbonaceous material from marine waste: chitosan-derived layered CNX catalyst for aerial oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid

    Data.gov (United States)

    U.S. Environmental Protection Agency — Chitosan-derived, porous and layered nitrogen-enriched carbonaceous CNx catalyst (PLCNx) has been synthesized from marine waste and its use demonstrated in a...

  16. [Composition and variation characteristics of atmospheric carbonaceous species in PM 2.5 in Taiyuan, China].

    Science.gov (United States)

    Zhang, Gui-xiang; Yan, Yu-long; Guo, Li-li; He, Qiu-sheng; Chen, Lai-guo

    2015-03-01

    Day-night variation characteristics of organic carbon (OC) and elemental carbon (EC) in atmospheric fine particles (PM2.5) collected during winter of 2009 and spring of 2010 in Taiyuan city were analyzed using DRI Model 2001A Thermal/Optical Carbon Analyzer, and the sources of carbonaceous materials in PM2.5 were analyzed. The results showed that the average concentrations of PM2.5, OC, EC and average OC/EC ratios were all higher during winter [(289.2 ± 104.8) μg x m(-3), (65.2 ± 22.1) μg x m(-3), (23.5 ± 8.2) μg x m(-3) and 2.8 ± 0.3] than during spring [(248.6 ± 68.6) μg x m(-3), (29.7 ± 6.2) μg x m(-3), (20.2 ± 5.4) μg x m(-3) and 1.5 ± 0.3], higher in nighttime [(309.3 ± 150.0) μg x m(-3), (74.6 ± 19.5) μg x m(-3), (24.3 ± 6.6) μg x m(-3) and 3.1 ± 0.3] than in daytime [(234.9 ± 122.1) μg x m(-3), (54.9 ± 28.2) μg x m(-3), (22.6 ± 10.8) μg x m(-3) and 2.5 ± 0. 5] during winter while higher in daytime [(292.5 ± 120.8) μg x m(-3), (32.7 ± 10.5) μg x m(-3), (22.7 ± 10.1) μg x m(-3) and 1.6 ± 0.5] than in nighttime [(212.3 ± 36.7) μg x m(-3), (29.6 ± 6.6) μg x m(-3), (20.7 ± 6.4) μg x m(-3) and 1.5 ± 0.2] during spring. This result was explained by the fact that winter is a "heating season", especially in nighttime, emission of carbonaceous particles was increased because of the increase of coal and biomass combustion and diffusion of pollutants was difficult because of low atmospheric temperature and stable atmospheric conditions; and high OC/EC was caused by increase of OC emission but not contribution of secondary organic carbon (SOC) since low temperature and weak solar radiation were not favorable for the formation of SOC. The higher concentrations of PM2.5, OC and EC in daytime than in nighttime during spring might be due to more dust in daytime because of higher wind speed and lower relative humidity in daytime than in nighttime, and the higher OC/EC in daytime than in nighttime might be caused by higher temperature

  17. Empiryczna weryfikacja hipotezy o przenośności modelu Altmana na warunki polskiej gospodarki oraz uniwersalności sektorowej modeli

    Directory of Open Access Journals (Sweden)

    Tomasz Iwanowicz

    2018-03-01

    Full Text Available Celem artykułu jest próba udzielenia odpowiedzi na pytanie, czy istnieje uzasadnienie dla mechanicznego przenoszenia modelu Altmana na warunki polskiej gospodarki oraz sprawdzenie, czy wśród testowanych modeli istnieje model wykazujący dla każdego typu przedsiębiorstwa (przemysłowe, handlowe, usługo- we najwyższą skuteczność i najlepsze wartości zastosowanych metod porównawczych. W artykule porównano trzynaście testowanych modeli używając macierzy klasyfikacji, ilorazu szans, krzywej kon- centracji CAP i wskaźnika dokładności Giniego, będących metodami oceny sprawności, oraz wskaźnika Briera będącego metodą oceny modeli z punktu widzenia kryterium kalibracji. Badania zostały przepro- wadzone na bazie 439 sprawozdań finansowych opublikowanych przez 139 spółek kapitałowych zarejestrowanych w warszawskich sądach okręgowych i rejonowych (w tym 79 spółek, które w rzeczywistości ogłosiły upadłość. Przeprowadzone badania obaliły mit o przenośności modelu Altmana na warunki polskiej gospodarki oraz uniwersalności sektorowej modeli. Wykazano, że sprawność modeli różni się dla spółek produkcyjnych, handlowych i usługowych oraz określono te sprawności. Ponadto udowodniono, że istnieją modele dyskryminacyjne różniące się zestawem zmiennych oraz współczynnikami wagowymi, które wykazują zbliżone skuteczności predykcyjne. The purpose of this paper is to answer the question about the validity of mechanical transfer of the Alt- man model to Polish economy and to check if among the tested models there is a model with the highest efficiency and best outcomes for the used comparative methods for each type of enterprise (manufactur- ing, trading, service. Thirteen tested models were compared using the classification matrix, odds ratio, CAP concentration curve and Gini accuracy index, which are efficiency evaluation methods, as well as using the Brier index, which is a method of evaluating models

  18. BIOGRAMY POLSKICH MYŚLICIELI NIERUCHOMOŚCI

    Directory of Open Access Journals (Sweden)

    Edyta Łazarowicz

    2009-11-01

    Full Text Available Fragment artykułu: [b]Andrzej Bieniek[/b] (1895-1944, doktor, urodził się 17 października 1895 r. w Bratucicach (powiat Bochnia, rozstrzelany 26 lipca 1944 roku w ruinach getta w Warszawie. (...Doktor A. Bieniek zajmował się głównie problemami organizacji księgowości w przedsiębiorstwach oraz rachunkiem kosztów. Był autorem m.in. następujących publikacji: Polska metoda księgowości oparta na ekonomicznym systemie Taylora (Biblioteka Państwowej Szkoły Handlowej Męskiej w Łodzi, Łódź 1927, Kantor wzorowy w szkołach handlowych (Biblioteka Państwowej Szkoły Handlowej Męskiej w Łodzi, Warszawa-Łódź 1928, Księgowość w przedsiębiorstwach przemysłowych (Biblioteka Rady Głównej Zrzeszeń Księgowych i Rzeczoznawców Księgowości w Polsce, Warszawa 1935, Zasady inwentaryzacji i bilansowania (Związek Księgowych w Polsce, Warszawa 1936, Organizacja rachunkowości w przedsiębiorstwach przemysłowych ((Związek Księgowych w Polsce, Warszawa 1939, Zasady analizy bilansów (Stowarzyszenie Nauczycieli Szkół Zawodowych. Sekcja Główna Handlowa, Warszawa 1939. [b]Zygmunt Stefan Kossut[/b] (1922–1984 profesor doktor habilitowany, syn Wiktora Kossuta i Henryki Serafin, urodził się 16 kwietnia 1922 r. (.. Do dzisiaj znane jest profesjonalistom zdanie E. Terebuchy, że „on pierwszy (Z. Kossut – M.G. przeorał ugór w naszej nauce rachunkowości, wykonując próbę sformułowania nowych poglądów na metody badawcze w dziedzinie teorii rachunkowości.” [b]Kazimierz Sowa[/b] (1915–1972, profesor nadzwyczajny, doktor, urodził się 2 października 1915 roku w Krakowie w rodzinie chłopskiej, zmarł 17 grudnia 1972 r. w Krakowie. Był żonaty, bezdzietny. (... Okres pracy zawodowej Kazimiera Sowy (1938–1972 był bardzo zróżnicowany i przebiegał wielotorowo. Była to praca naukowo-dydaktyczna w szkolnictwie wyższym, praca redakcyjno-popularyzatorska, organizacyjno-kierownicza w Stowarzyszeniu Księgowych w

  19. Characterization of Chiral Carbonaceous Nanotubes Prepared from Four Coiled Tubular 4,4'-biphenylene-silica Nanoribbons

    Directory of Open Access Journals (Sweden)

    Shuwei Lin

    2014-04-01

    Full Text Available Four dipeptides derived from phenylalanine were synthesized, which can self-assemble into twisted nanoribbon in deionized water. The handedness of the organic self-assemblies was controlled by the chirality of the phenylalanine at the terminals. Coiled 4,4'-biphenylene bridged polybissilsesquioxane tubular nanoribbons were prepared using the organic self-assemblies as the templates. The circular dichroism spectra indicated that the biphenylene rings preferred to twist in one-handedness within the walls of the samples. After carbonization and removal of silica, single-handed coiled carbonaceous tubular nanoribbons were obtained. The Raman spectra indicated that the carbon was amorphous. The diffuse reflectance circular dichroism spectra indicated the tubular carbonaceous nanoribbons exhibited optical activity.

  20. Characteristics of PM2.5 Carbonaceous Aerosol in Urban New York State

    Science.gov (United States)

    Khwaja, H. A.; Dutkiewicz, V.; Briggs, R.; Siddique, A.; Regan, J.

    2008-12-01

    In order to investigate the characteristics of carbonaceous fine aerosols, PM2.5 and size-segregated particulate samples (Botanical Garden (BTG), New York City and Empire State Plaza (ESP), Albany. Gas phase organic compounds were sampled with polyurethane foam (PUF) plugs. Particulate samples were acquired on quartz fiber filters using a high-volume air sampler (Hi-Vol) attached with a slotted impactor. Filters were sonicated in dichloromethane:methanol (9:1); extracts concentrated. A suite of more than 200 individual organic compounds was identified in the PM2.5 samples. Molecular markers, homologous compound series, and non-polar and polar organic compounds were detected at ng/m3 ambient concentrations using gas chromatography/mass spectrometry (GC/MS). Measurements of the organic carbon (OC) and elemental carbon (EC) were also made. Organic compounds detected in the size-segregated samples were grouped into different classes including phthalates and adipates, n-alkanes, alkanoic acids, cyclic siloxanes, waxes, benzoates, polyethylene glycols, squalene, and 4-nitro-butylated phenol. Results indicated that these organic species were predominantly associated in the fine particle mode (extractable and elutable organic carbon was found to correspond to a complex mixture of phthalates and adipates, benzoate esters, n-alkanes, methyl silicates, phosphate esters, aldehydes and ketones, alcohols, alkyl amines, nitrosamines, formamides, amides, morpholines, carboxylic acids, methyl and isopropyl esters, dicarboxylic acids, waxes, lactones, hopanes, ionol 2, and PAHs. The most abundant classes of compounds are carboxylic acids, followed by phthalates and adipates, n-alkanes, and alkyl amines. At the BTG, OC and EC concentrations were measured to be 4.7 and 0.31 μg/m3, respectively, whereas at the ESP their concentrations were 4.4 and 0.43 μg/m3, respectively. Source-receptor relationships of fine carbonaceous particles were investigated by air mass back

  1. Detection of Carbonaceous Aerosols Released in CNT Workplaces Using an Aethalometer.

    Science.gov (United States)

    Kim, Jong Bum; Kim, Kyung Hwan; Yun, Seong-Taek; Bae, Gwi-Nam

    2016-07-01

    Black carbon (BC) originating from various combustion sources has been extensively surveyed to characterize the effects of BC on global warming and human health, and many online monitors are available. In this study, BC was considered as a surrogate for carbon-based nanomaterials in an occupational health study. Specifically, BC concentrations were monitored continuously with an aethalometer for 24h at four carbon nanotube (CNT) workplaces located in rural, urban, and industrial areas, which had different background air pollution levels. Average BC concentrations for both nonworking (background) and working periods were compared with the recommended exposure limit (REL) of 1 μg m(-3) for elemental carbon that was suggested by the National Institute for Occupational Safety and Health (NIOSH). Diurnal variation of BC concentrations indicated that BC measurements corresponded well with carbonaceous aerosols such as vehicle exhaust particles and CNT aerosols. In the rural CNT workplace, the average background BC concentration (0.36 μg m(-3)) was lower than the REL, but the BC concentration without background correction was higher than the REL during manufacturing hours. In this case, BC measurement is useful to estimate CNT exposure for comparison with the REL. Conversely, in the urban and industrial CNT workplaces, average background BC concentrations (2.05, 1.82, and 2.64 μg m(-3)) were well above the REL, and during working hours, BC concentrations were substantially higher than the background level at workplace C; however, BC concentrations showed no difference from the background levels at workplaces B and D. In these cases (B and D), it is hard to determine CNT exposure because of the substantial environmental exposures. Most of the urban ambient BC concentrations were above the REL. Therefore, further analysis and test methods for carbonaceous aerosols need to be developed so that the exposure assessment can be easily carried out at CNT workplaces with high

  2. Combustion Stratification for Naphtha from CI Combustion to PPC

    KAUST Repository

    Vallinayagam, R.

    2017-03-28

    This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON = 46). The motored pressure at TDC is maintained at 35 bar and fuelMEP is kept constant at 5.1 bar to account for the difference in fuel properties between naphtha and diesel. Single injection strategy is employed and the fuel is injected at a pressure of 800 bar. Photron FASTCAM SA4 that captures in-cylinder combustion at the rate of 10000 frames per second is employed. The captured high speed video is processed to study the combustion homogeneity based on an algorithm reported in previous studies. Starting from late fuel injection timings, combustion stratification is investigated by advancing the fuel injection timings. For late start of injection (SOI), a direct link between SOI and combustion phasing is noticed. At early SOI, combustion phasing depends on both intake air temperature and SOI. In order to match the combustion phasing (CA50) of diesel, the intake air temperature is increased to 90°C for naphtha. The combustion stratification from CI to PPC is also investigated for various level of dilution by displacing oxygen with nitrogen in the intake. The start of combustion (SOC) was delayed with the increase in dilution and to compensate for this, the intake air temperature is increased. The mixture homogeneity is enhanced for higher dilution due to longer ignition delay. The results show that high speed image is initially blue and then turned yellow, indicating soot formation and oxidation. The luminosity of combustion images decreases with early SOI and increased dilution. The images are processed to generate the level of stratification based on the image intensity. The level of stratification is same for diesel and naphtha at various SOI. When O concentration in the intake is decreased to 17.7% and 14

  3. On the nature of the symbiotic binary CI Cygni

    International Nuclear Information System (INIS)

    Kenyon, S.J.; Oliversen, N.A.; Mikolajewska, J.; Mikolajewski, M.; Stencel, R.E.

    1991-01-01

    An analysis of ultraviolet and optical spectroscopy is presented for the symbiotic binary CI Cyg. This system contains an M5 II asymptotic branch giant Mg of about 1.5 solar mass, transfering material at a few times 0.00001 solar mass/yr into a large accretion disk surrounding a main-sequence star with Mh of about 0.5 solar mass. A boundary layer at the inner edge of the disk photoionizes a small nebula approximately confined to the Roche volume of the accreting star. An extended, more highly ionized region forms when material ejected from the disk interacts with the red giant wind. 115 refs

  4. COMPARATIVE STUDY ON METAL IONS ADSORPTION ON A LOW COST CARBONACEOUS ADSORBENT KINETIC EQUILIBRIUM AND MECHANISTIC STUDIES

    OpenAIRE

    S. Arivoli, M. Hema, C. Barathiraja

    2008-01-01

    A carbonaceous adsorbent prepared from an indigenous waste and treated by acid was tested for its efficiency in removing metal ions of Fe(II), Co(II) and Ni(II). The process parameters studied included agitation time, initial metal ion concentration, carbon dosage, pH, other ions and temperature. The kinetics of adsorption followed first order reaction equation and the rate was mainly controlled by intraparticle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibriu...

  5. Carbon isotope-constrained seasonality of carbonaceous aerosol sources from an urban location (Kanpur) in the Indo-Gangetic Plain

    Science.gov (United States)

    Bikkina, Srinivas; Andersson, August; Ram, Kirpa; Sarin, M. M.; Sheesley, Rebecca J.; Kirillova, Elena N.; Rengarajan, R.; Sudheer, A. K.; Gustafsson, Örjan

    2017-05-01

    The Indo-Gangetic Plain (IGP) in northern India, Pakistan, and Bangladesh is a major source of carbonaceous aerosols in South Asia. However, poorly constrained seasonality of their sources over the IGP leads to large uncertainty in climate and health effects. Here we present a first data set for year-round radiocarbon (Δ14C) and stable carbon (δ13C)-based source apportionment of total carbon (TC) in ambient PM10 (n = 17) collected from an urban site (Kanpur: 26.5°N, 80.3°E) in the IGP during January 2007 to January 2008. The year-round 14C-based fraction biomass (fbio-TC) estimate at Kanpur averages 77 ± 7% and emphasizes an impact of biomass burning emissions (BBEs). The highest fbio-TC (%) is observed in fall season (October-November, 85 ± 6%) followed by winter (December-February, 80 ± 4%) and spring (March-May, 75 ± 8%), while lowest values are found in summer (June-September, 69 ± 2%). Since biomass/coal combustion and vehicular emissions mostly contribute to carbonaceous aerosols over the IGP, we predict δ13CTC (δ13Cpred) over Kanpur using known δ13C source signatures and the measured Δ14C value of each sample. The seasonal variability of δ13Cobs - δ13Cpred versus Δ14CTC together with air mass back trajectories and Moderate Resolution Imaging Spectroradiometer fire count data reveal that carbonaceous aerosols in winter/fall are significantly influenced by atmospheric aging (downwind transport of crop residue burning/wood combustion emissions in the northern IGP), while local sources (wheat residue combustion/vehicular emissions) dominate in spring/summer. Given the large temporal and seasonal variability in sources and emission strength of TC over the IGP, 14C-based constraints are, thus, crucial for reducing their uncertainties in carbonaceous aerosol budgets in climate models.

  6. Process for the liquefaction of solid carbonaceous materials wherein nitrogen is separated from hydrogen via ammonia synthesis

    Science.gov (United States)

    Stetka, Steven S.; Nazario, Francisco N.

    1982-01-01

    In a process for the liquefaction of solid carbonaceous materials wherein bottoms residues are upgraded with a process wherein air is employed, the improvement wherein nitrogen buildup in the system is avoided by ammonia synthesis. In a preferred embodiment hydrogen from other portions of the liquefaction process will be combined with hydrogen produced as a result of the bottoms upgrading to increase the H.sub.2 :N.sub.2 ratio in the ammonia reactor.

  7. COMBINED THEORETICAL AND EXPERIMENTAL INVESTIGATION OF MECHANISMS AND KINETICS OF VAPOR-PHASE MERCURY UPTAKE BY CARBONACEOUS SURFACES; ANNUAL

    International Nuclear Information System (INIS)

    Radisav D. Vidic; Eric V. Borguet; Karl J. Johnson

    2000-01-01

    The overall goal of this research program is to gain fundamental understanding of the important chemistry and physics involved in mercury adsorption on carbonaceous surfaces. This knowledge will then be used to optimize adsorption processes and operating conditions to maximize the uptake of mercury within the required contact time. An additional long-term benefit of this research is the basic understanding of the Hg adsorption process, which may facilitate the design of new adsorbents for more efficient and cost-effective removal of Hg from a variety of effluent streams. Molecular modeling of the adsorption of Hg on carbonaceous surfaces will greatly increase the insight into the physics of the adsorption process and combined with in situ rate measurements of mercury adsorption and desorption (conventional and pulsed laser) on graphite using linear and nonlinear optical probes with real time optical resolution have the potential to provide fundamental insight into the process of mercury uptake by carbonaceous surfaces. Besides accurate assessment of key parameters influencing adsorption equilibrium, fundamental understanding of the kinetics of mercury adsorption, desorption, and diffusion will be developed in this study. These key physical and chemical processes postulated through molecular modeling efforts and verified by in situ measurements will be utilized to select (or develop) promising sorbents for mercury control, which will be tested under dynamic conditions using simulated flue gas

  8. Impact of carbonaceous materials in soil on the transport of soil-bound PAHs during rainfall-runoff events

    International Nuclear Information System (INIS)

    Luo, Xiaolin; Zheng, Yi; Wu, Bin; Lin, Zhongrong; Han, Feng; Zhang, Wei; Wang, Xuejun

    2013-01-01

    Polycyclic Aromatic Hydrocarbons (PAHs) transported from contaminated soils by surface runoff pose significant risk for aquatic ecosystems. Based on a rainfall-runoff simulation experiment, this study investigated the impact of carbonaceous materials (CMs) in soil, identified by organic petrology analysis, on the transport of soil-bound PAHs under rainfall conditions. The hypothesis that composition of soil organic matter significantly impacts the enrichment and transport of PAHs was proved. CMs in soil, varying significantly in content, mobility and adsorption capacity, act differently on the transport of PAHs. Anthropogenic CMs like black carbon (BC) largely control the transport, as PAHs may be preferentially attached to them. Eventually, this study led to a rethink of the traditional enrichment theory. An important implication is that CMs in soil have to be explicitly considered to appropriately model the nonpoint source pollution of PAHs (possibly other hydrophobic chemicals as well) and assess its environmental risk. -- Highlights: •Composition of SOM significantly impacts the enrichment and transport of PAHs. •Anthropogenic carbonaceous materials in soil largely control the transport of PAHs. •The classic enrichment theory is invalid if anthropogenic CMs are abundant in the soil. •Organic petrology analysis introduced to study the fate and transport of PAHs. -- Anthropogenic carbonaceous materials in soil, especially black carbon, largely control the transport of soil-bound PAHs during rainfall-runoff events

  9. Organochemical characteristics of carbonaceous materials as indicators of heat recorded on an ancient plate-subduction fault

    Science.gov (United States)

    Kaneki, S.; Hirono, T.; Mukoyoshi, H.; Sampei, Y.; Ikehara, M.

    2016-07-01

    Coseismic shear stress and slip distance affect subduction-related earthquake processes. They need to be understood to evaluate the earthquake's mechanism and the tsunami generation potential near trenches. The amount of frictional heat generated depends on the shear stress and slip distance, which are therefore able to be derived from the temperature recorded in the fault. Here we developed a new temperature proxy for carbonaceous materials by performing spectroscopic, thermogravimetric, and organic elemental analyses in conjunction with heating experiments. We found marked anomalies in the infrared and Raman spectra and atomic compositions of carbonaceous materials retrieved from the slip zone of an ancient megasplay fault in the Cretaceous Shimanto accretionary complex, Japan: the infrared spectra show extinction of aliphatic C-H bonding and very weak aromatic C=C bonding, and the Raman spectra show a slightly elevated ratio of disordered band intensity to graphitic band intensity and relatively low H/C and O/C ratios. These correlate well with the spectral and elemental features of host-rock carbonaceous materials after heating to 600°C. Thus, we conclude that the slip zone experienced a temperature of 600°C during a past earthquake event, indicating coseismic slip of 2-9 m, which could have generated a large tsunami if the ruptures propagated to the seafloor.

  10. Ciência, sociedade e universidade Science, society and university

    Directory of Open Access Journals (Sweden)

    Pedro Goergen

    1998-08-01

    Full Text Available Este trabalho busca repensar a relação entre ciência, sociedade e universidade a partir das transformações que marcam a contemporaneidade. A hipótese é de que estas mudanças de níveis econômico, laboral e mesmo epistêmico afetam também o sentido da prática acadêmica. A partir da reflexão sobre os três conceitos que compõem o título do artigo - ciência, sociedade e universidade -, conclui-se que a universidade deve iniciar um processo de auto-avaliação que inclua seus próprios fundamentos, ainda modernos, na perspectiva do novo cenário. Esta reflexão básica deve constituir o ponto de partida para uma futura reforma universitária.This paper aims to rethink the relationship between science, society and university from the transformations that mark the contemporary time. The hypothesis is that the changes in economical, labor and epistemic lewels also affect the meaning of academic practice. Reflecting upon the three concepts present in the title of this article - science, society and university - we conclude that university must rethink its identity establish. This basic reflexive thinking should be the first concern to a university reform.

  11. Diversidade sexual e ensino de ciências: buscando sentidos

    Directory of Open Access Journals (Sweden)

    Leandro Jorge Coelho

    2015-12-01

    Full Text Available ResumoO objetivo desse estudo foi analisar os sentidos atribuídos por professores de Ciências e alunos à diversidade sexual. Foram utilizados: questionário, entrevista, produção de textos, análise documental e a técnica de grupo focal para a coleta de dados. De modo geral, os alunos possuem sentidos que reconhecem Lésbicas, Gays, Bissexuais e Transgêneros (LGBT como "estranhos", mesmo assim, acreditam que têm o dever de respeitar as escolhas de cada um. As travestis foram declaradamente apresentadas com repúdio por eles, sendo a homossexualidade e bissexualidade aparentemente mais aceitas. Os professores parecem manter aulas que não abordam estas questões, mesmo o Ensino de Ciências, sendo um momento privilegiado para problematizações sobre diversidade sexual e gênero. É necessário investir em discussões sobre esses temas na formação inicial e continuada de professores, buscando a construção de novos sentidos e práticas que se preocupem com o desvelamento de significados preconceituosos sobre gênero e diversidade sexual.

  12. Emission Characteristics of a CI Engine Running with a Range of Biodiesel Feedstocks

    Directory of Open Access Journals (Sweden)

    Belachew Tesfa

    2014-01-01

    Full Text Available Currently, alternative fuels are being investigated in detail for application in compression ignition (CI engines resulting in exciting potential opportunities to increase energy security and reduce gas emissions. Biodiesel is one of the alternative fuels which is renewable and environmentally friendly and can be used in diesel engines with little or no modifications. The objective of this study is to investigate the effects of biodiesel types and biodiesel fraction on the emission characteristics of a CI engine. The experimental work was carried out on a four-cylinder, four-stroke, direct injection (DI and turbocharged diesel engine by using biodiesel made from waste oil, rapeseed oil, corn oil and comparing them to normal diesel. The fuels used in the analyses are B10, B20, B50, B100 and neat diesel. The engine was operated over a range of engine speeds. Based on the measured parameters, detailed analyses were carried out on major regulated emissions such as NOx, CO, CO2, and THC. It has been seen that the biodiesel types (sources do not result in any significant differences in emissions. The results also clearly indicate that the engine running with biodiesel and blends have higher NOx emission by up to 20%. However, the emissions of the CI engine running on neat biodiesel (B100 were reduced by up to 15%, 40% and 30% for CO, CO2 and THC emissions respectively, as compared to diesel fuel at various operating conditions.

  13. Structural and functional properties of chimeric EspA-FliCi filaments of EPEC.

    Science.gov (United States)

    Crepin, Valerie F; Martinez, Eric; Shaw, Robert K; Frankel, Gad; Daniell, Sarah J

    2008-04-18

    Enteropathogenic Escherichia coli utilise a filamentous type III secretion system to translocate effector proteins into host gut epithelial cells. The primary constituent of the extracellular component of the filamentous type III secretion system is EspA. This forms a long flexible helical conduit between the bacterium and host and has a structure almost identical to that of the flagella filament. We have inserted the D3 domain of FliCi (from Salmonella typhimurium) into the outer domain of EspA and have studied the structure and function of modified filaments when expressed in an enteropathogenic E. coli espA mutant. We found that the chimeric protein EspA-FliCi filaments were biologically active as they supported protein secretion and translocation [assessed by their ability to trigger actin polymerisation beneath adherent bacteria (fluorescent actin staining test)]. The expressed filaments were recognised by both EspA and FliCi antisera. Visualisation and analysis of the chimeric filaments by electron microscopy after negative staining showed that, remarkably, EspA filaments are able to tolerate a large protein insertion without a significant effect on their helical architecture.

  14. ANALIZA TRWAŁOŚCI STALOWYCH OBIEKTÓW MOSTOWYCH W ZALEŻNOŚCI OD ŚRODOWISKA KOROZYJNEGO

    Directory of Open Access Journals (Sweden)

    Anna ŚPIEWAK

    Full Text Available W artykule przedstawiono aktualne statystyki dotyczące sieci dróg województwa śląskiego zarządzanych przez Zarząd Dróg Wojewódzkich oraz ilości konstrukcji w zależności od typu ich ustroju nośnego. Poruszono aktualny w Polsce problem dotycząc trwałości stalowych obiektów mostowych z uwzględnieniem zjawiska korozji. Scharakteryzowano podstawowe czynniki wpływające na szybkość korozji niezbędne do oszacowania wpływu korozji na trwałość stalowych mostów drogowych m.in. czynniki atmosferyczne oraz czynniki wynikające z utrzymania obiektu. Zwrócono szczególną uwagę na kategorie korozyjności środowiska w którym wznoszone są konstrukcje stalowe, mające bardzo znaczący wpływ na postęp i szybkość procesu korozji. Omówiono procedurę badania wpływu korozji na trwałość stalowych konstrukcji mostowych opracowaną przez Instytut Badawczy Dróg i Mostów. Przedstawiono metodę obliczania czasu bezawaryjnego użytkowania konstrukcji. Szczegółowo scharakteryzowano, niezbędne do przeprowadzenia procedury obliczeniowej, redukcyjne współczynniki trwałości. Na podstawie własnej analizy określono czas bezawaryjnej pracy wybranych konstrukcji. Do obliczeń przyjęto cztery rzeczywiste mosty o dźwigarach stalowych, będących konstrukcją nośną dla żelbetowej płyty pomostowej. Wybrane mosty wzniesione zostały w różnych częściach kraju, charakteryzujących się odmienną agresywnością środowiska – środowisko nadmorskie, górskie, miejskie oraz neutralne. Obiekty różnią się rodzajem korozji występującym na ustrojach nośnych konstrukcji. Mosty różnią się również czasem powstania obiektów, co wpływa w znacznym stopniu na ich bezpieczne użytkowanie. Na zakończenie przeanalizowano wyniki otrzymane z przeprowadzonej analizy.

  15. Comparative evaluation for the sorption capacity of four carbonaceous sorbents to phenol

    Directory of Open Access Journals (Sweden)

    Ding Feng Jin

    2016-10-01

    Full Text Available Sorption kinetics and isotherms of phenol by four carbonaceous sorbents (activated carbon (AC, mesoporous carbon (MPC, bamboo biochar (BBC and oak wood biochar (OBC were compared in this study. MPC has the fastest sorption rate and initial sorption potential, which were indicated by sorption rate constants and initial sorption rate “h” in a pseudo-second-order kinetic model. The ordered and straight pore structure of MPC facilitated the accessibility of phenol. The AC showed the greatest sorption capacity towards phenol with maximum sorption of 123 mg/g as calculated by the Langmuir model. High surface area, complexity of pore structure, and the strong binding force of the π–π electron-donor-acceptor interaction between phenol molecules and AC were the main mechanisms. The BBC and OBC had much slower sorption and lower sorption capacity (33.04 and 29.86 mg/g, respectively, compared to MPC (73.00 mg/g and AC, indicating an ineffective potential for phenol removal from water.

  16. Biomineralization-Inspired Synthesis of Cerium-Doped Carbonaceous Nanoparticles for Highly Hydroxyl Radical Scavenging Activity

    Science.gov (United States)

    Zou, Shenqiang; Zhu, Xiaofang; Zhang, Lirong; Guo, Fan; Zhang, Miaomiao; Tan, Youwen; Gong, Aihua; Fang, Zhengzou; Ju, Huixiang; Wu, Chaoyang; Du, Fengyi

    2018-03-01

    Cerium oxide nanoparticles recently have received extensive attention in biomedical applications due to their excellent anti-oxidation performance. In this study, a simple, mild, and green approach was developed to synthesize cerium-doped carbonaceous nanoparticles (Ce-doped CNPs) using bio-mineralization of bull serum albumin (BSA) as precursor. The resultant Ce-doped CNPs exhibited uniform and ultrasmall morphology with an average size of 14.7 nm. XPS and FTIR results revealed the presence of hydrophilic group on the surface of Ce-doped CNPs, which resulted in excellent dispersity in water. The CCK-8 assay demonstrated that Ce-doped CNPs possessed favorable biocompatibility and negligible cytotoxicity. Using H2O2-induced reactive oxygen species (ROS) as model, Ce-doped CNPs showed highly hydroxyl radical scavenging capability. Furthermore, flow cytometry and live-dead staining results indicated that Ce-doped CNPs protected cells from H2O2-induced damage in a dose-dependent effect, which provided a direct evidence for anti-oxidative performance. These findings suggest that Ce-doped CNPs as novel ROS scavengers may provide a potential therapeutic prospect in treating diseases associated with oxidative stress.

  17. Characterization of carbonaceous combustion residues. I. Morphological, elemental and spectroscopic features.

    Science.gov (United States)

    Fernandes, Milena B; Skjemstad, Jan O; Johnson, Bruce B; Wells, John D; Brooks, Peter

    2003-06-01

    Scanning electron microscopy, surface area determination, elemental analysis, organic matter extraction and solid-state cross polarization/magic angle spinning and Bloch decay/magic angle spinning 13C nuclear magnetic resonance (NMR) spectroscopy were used to investigate distinctive features among carbonaceous combustion residues. Black carbon (BC) samples included diesel soot, urban dust, carbon black, chimney soot, vegetation fire residues, wood and straw charcoals. Particles varied from small spheres (100 m(2)/g), to large layered structures in plant-derived BC (generally 1 micrometer) liquid-like structures, while spherules >100 nm were unique to urban dust. The ratios of amorphous to soot carbon (SC) (isolated by thermal degradation) were not necessarily correlated with the degree of aromaticity estimated from H/C ratios. In particular, values of SC in diesel soot were clearly overestimated. Solvent-extractable organic matter (SEOM) was 13% for urban dust, chimney and diesel soot. SEOM is thought to clog pores or to form large waxy globules, hence reducing surface areas. The ratio of polar/nonpolar SEOM was generally 30 for plant-derived BC. NMR analysis revealed essentially one chemical shift in the aromatic C region of charcoals, while diesel soot also showed important aliphatic contributions. Aliphatic and oxygenated C predominated over aryl C in urban dust and chimney soot. These morphological and chemical characteristics of the BC samples are discussed in terms of their environmental implications.

  18. Pair distribution functions of carbonaceous solids, determined using energy filtered diffraction

    International Nuclear Information System (INIS)

    Petersen, T.C.; McCulloch, D.G.

    2002-01-01

    Full text: The structures of various carbonaceous solids were investigated using energy filtered diffraction patterns collected in two dimensions using a Gatan Imaging Filter (GIF). In order to reduce multiple scattering and eliminate inelastic scattering effects, the diffraction patterns were filtered using an energy -selecting slit around the zero-loss peak. Software has been developed for the extraction of radially averaged pair distributions functions from the diffraction data. This entails finding the position of the un-scattered beam, radially averaging the two dimensional intensity distributions, calibrating the resulting one dimensional intensity profiles and finally normalising the data to obtain structure factors. Techniques for improving and assessing data quality, pertaining to the methodology used here, have also been explored. Structure factors and radial distribution functions generated using this analysis will be discussed and, for the commercial V25 glassy carbon samples, compared to previous, work of one of the authors'. In order to answer questions regarding multiple scattering effects and structural homogeneity of the samples, neutron scattering was performed on the Medium Resolution Powder Diffractometer (MRPD), at the Australian Nuclear Science and Technology's (ANSTO) facility. A critical comparison of the neutron scattering and electron diffraction generated structure factors will be presented. Copyright (2002) Australian Society for Electron Microscopy Inc

  19. Removal of fluoride ions from water by adsorption onto carbonaceous materials produced from coffee grounds.

    Science.gov (United States)

    Ogata, Fumihiko; Tominaga, Hisato; Yabutani, Hitoshi; Kawasaki, Naohito

    2011-01-01

    Carbonaceous material for the removal of fluoride ions from water was prepared from coffee grounds (CGs) by calcination and subsequent HCl treatment. The characteristics of the CGs, including the surface area, mean pore diameter, pore volume, and surface functional groups were determined, and the morphological characteristics were evaluated using scanning electron microscopy. The adsorption isotherms, saturated amount of fluoride ions adsorbed, and the effect of contact time and temperature on the adsorption of fluoride ions were investigated for a sample of tap water. The specific surface area of CG calcined at 600° (CG600) was larger than that of CGs calcined at 400, 800, and 1000°. Phenolic, lactonic, and carboxyl groups were detected on the CG600 surface. The adsorption capacity of the carbonized CGs for fluoride was ranked in the order CG400 < CG1000 < CG800 < CG600 (where the numeral indicates the carbonization temperature), whereas virgin CG and CG600-NAT (not treated with hydrochloric acid solution) did not exhibit any adsorption ability for fluoride ions. The amount of fluoride ions adsorbed onto CG600 increased with increasing temperature and was consistent with chemical adsorption. The mechanism of adsorption of fluoride ions onto CG600 proceeded via ion exchange with chloride ions (1:1) present on the surface of CG600. The adsorption isotherms were fitted to the Freundlich and Langmuir equations. Moreover, CG600 showed an acceptable adsorption capacity for fluoride ions present in tap water.

  20. Rapid contamination during storage of carbonaceous chondrites prepared for micro FTIR measurements

    Science.gov (United States)

    Kebukawa, Y.; Nakashima, S.; Otsuka, T.; Nakamura-Messenger, K.; Zolensky, M. E.

    2009-05-01

    Organic contamination (~2965 and ~1260 cm-1 peaks) was found on Tagish Lake (C2) and Murchison (CM2) carbonaceous chondrites containing abundant hydrous minerals by Fourier transform infrared (FTIR) microspectroscopy on the samples pressed on Al plates. On the other hand, anhydrous chondrite (Moss, CO3) was not contaminated. This contamination occurred within one day of storage, when the samples pressed on Al were stored within containers including silicone rubber mats. Volatile molecules having similar peaks to the contaminants were detected by long-path gas cell FTIR measurements for the silicone rubber mat. Rapid adsorption of the volatile contaminants also occurred when silica gel and hydrous minerals such as serpentine were stored in containers including silicone rubber, silicone grease, or adhesive tape. However, they did not show any contamination when stored in glass and polystyrene containers without these compounds. Therefore, precious astronomical samples such as meteorites, interplanetary dust particles (IDPs), and mission-returned samples from comets, asteroids, and Mars, should be measured by micro FTIR within one day of storage in glass containers without silicone rubber, silicone grease, or adhesive tape.

  1. Kinetics of the hydrothermal treatment of tannin for producing carbonaceous microspheres.

    Science.gov (United States)

    Braghiroli, F L; Fierro, V; Izquierdo, M T; Parmentier, J; Pizzi, A; Celzard, A

    2014-01-01

    Aqueous solutions of condensed tannins were submitted to hydrothermal carbonization (HTC) in a stainless steel autoclave, and the kinetics of hydrothermal carbon formation was investigated by changing several parameters: amount of tannin (0.5; 1.0; 1.5; 2.0 g in 16 mL of water), HTC temperature (130, 160, 180 and 200°C) and reaction times (from 1 to 720 h). The morphology and the structure of the tannin-based hydrothermal carbons were studied by TEM, krypton adsorption at -196°C and helium pycnometry. These materials presented agglomerated spherical particles, having surface areas ranging from 0.6 to 10.0 m(2) g(-1). The chemical composition of the hydrothermal carbons was found to be constant and independent of reaction time. HTC kinetics of tannin were determined and shown to correspond to first-order reaction. Temperature-dependent measurements led to an activation energy of 91 kJ mol(-1) for hydrothermal conversion of tannin into carbonaceous microspheres separable by centrifugation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Engineering Bacteria to Catabolize the Carbonaceous Component of Sarin: Teaching E. coli to Eat Isopropanol

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Margaret E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Mukhopadhyay, Aindrila [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Keasling, Jay D. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Univ. of California, Berkeley, CA (United States); Technical Univ. of Denmark, Horsholm (Denmark)

    2016-07-12

    In this paper, we report an engineered strain of Escherichia coli that catabolizes the carbonaceous component of the extremely toxic chemical warfare agent sarin. Enzymatic decomposition of sarin generates isopropanol waste that, with this engineered strain, is then transformed into acetyl-CoA by enzymatic conversion with a key reaction performed by the acetone carboxylase complex (ACX). We engineered the heterologous expression of the ACX complex from Xanthobacter autotrophicus PY2 to match the naturally occurring subunit stoichiometry and purified the recombinant complex from E. coli for biochemical analysis. Incorporating this ACX complex and enzymes from diverse organisms, we introduced an isopropanol degradation pathway in E. coli, optimized induction conditions, and decoupled enzyme expression to probe pathway bottlenecks. Our engineered E. coli consumed 65% of isopropanol compared to no-cell controls and was able to grow on isopropanol as a sole carbon source. Finally, in the process, reconstitution of this large ACX complex (370 kDa) in a system naïve to its structural and mechanistic requirements allowed us to study this otherwise cryptic enzyme in more detail than would have been possible in the less genetically tractable native Xanthobacter system.

  3. Spheroidal carbonaceous particles are a defining stratigraphic marker for the Anthropocene.

    Science.gov (United States)

    Swindles, Graeme T; Watson, Elizabeth; Turner, T Edward; Galloway, Jennifer M; Hadlari, Thomas; Wheeler, Jane; Bacon, Karen L

    2015-05-28

    There has been recent debate over stratigraphic markers used to demarcate the Anthropocene from the Holocene Epoch. However, many of the proposed markers are found only in limited areas of the world or do not reflect human impacts on the environment. Here we show that spheroidal carbonaceous particles (SCPs), a distinct form of black carbon produced from burning fossil fuels in energy production and heavy industry, provide unambiguous stratigraphic markers of the human activities that have rapidly changed planet Earth over the last century. SCPs are found in terrestrial and marine sediments or ice cores in every continent, including remote areas such as the high Arctic and Antarctica. The rapid increase in SCPs mostly occurs in the mid-twentieth century and is contemporaneous with the 'Great Acceleration'. It therefore reflects the intensification of fossil fuel usage and can be traced across the globe. We integrate global records of SCPs and propose that the global rapid increase in SCPs in sedimentary records can be used to inform a Global Standard Stratigraphic Age for the Anthropocene. A high-resolution SCP sequence from a lake or peatland may provide the much-needed 'Golden Spike' (Global Boundary Stratotype Section and Point).

  4. Factors affecting the indoor concentrations of carbonaceous aerosols of outdoor origin

    Energy Technology Data Exchange (ETDEWEB)

    Lunden, Melissa M.; Kirchstetter, Thomas W.; Thatcher, Tracy L.; Hering, Susanne V.; Brown, Nancy J.

    2007-06-25

    A field study was conducted in an unoccupied single story residence in Clovis, California to provide data to address issues important to assess the indoor exposure to particles of outdoor origin. Measurements of black and organic carbonaceous aerosols were performed using a variety of methods, resulting in both near real-time measurements as well as integrated filter based measurements. Comparisons of the different measurement methods show that it is crucial to account for gas phase adsorption artifacts when measuring organic carbon (OC). Measured concentrations affected by the emissions of organic compounds sorbed to indoor surfaces imply a higher degree of infiltration of outdoor organic carbon aerosols into the indoor environment for our unoccupied house. Analysis of the indoor and outdoor data for black carbon (BC) aerosols show that, on average, the indoor concentration of black carbon aerosols behaves in a similar manner to sulfate aerosols. In contrast, organic carbon aerosols are subject to chemical transformations indoors that, for our unoccupied home, resulted in lower indoor OC concentrations than would be expected by physical loss mechanisms alone. These results show that gas to particle partitioning of organic compounds, as well as gas to surface interactions within the residence, are an important process governing the indoor concentration to OC aerosols of outdoor origin.

  5. The Effect of Aqueous Alteration in Antarctic Carbonaceous Chondrites from Comparative ICP-MS Bulk Chemistry

    Science.gov (United States)

    Alonso-Azcarate, J.; Trigo-Rodriguez, J. M.; Moyano-Cambero, C. E.; Zolensky, M.

    2014-01-01

    Terrestrial ages of Antarctic carbonaceous chondrites (CC) indicate that these meteorites have been preserved in or on ice for, at least, tens of thousands of years. Due to the porous structure of these chondrites formed by the aggregation of silicate-rich chondrules, refractory inclusions, metal grains, and fine-grained matrix materials, the effect of pervasive terrestrial water is relevant. Our community defends that pristine CC matrices are representing samples of scarcely processed protoplanetary disk materials as they contain stellar grains, but they might also trace parent body processes. It is important to study the effects of terrestrial aqueous alteration in promoting bulk chemistry changes, and creating distinctive alteration minerals. Particularly because it is thought that aqueous alteration has particularly played a key role in some CC groups in modifying primordial bulk chemistry, and homogenizing the isotopic content of fine-grained matrix materials. Fortunately, the mineralogy produced by parent-body and terrestrial aqueous alteration processes is distinctive. With the goal to learn more about terrestrial alteration in Antarctica we are obtaining reflectance spectra of CCs, but also performing ICP-MS bulk chemistry of the different CC groups. A direct comparison with the mean bulk elemental composition of recovered falls might inform us on the effects of terrestrial alteration in finds. With such a goal, in the current work we have analyzed some members representative of CO and CM chondrite groups.

  6. Spheroidal carbonaceous fly ash particles provide a globally synchronous stratigraphic marker for the Anthropocene.

    Science.gov (United States)

    Rose, Neil L

    2015-04-07

    Human impacts on Earth are now so great that they have led to the concept of a new geological epoch defined by this global human influence: the Anthropocene. While not universally accepted, the term is increasingly popular and widely used. However, even among proponents, there is considerable debate regarding when the epoch may have started, from coeval with the Holocene, through the Industrial Revolution, to the mid-20th century when unprecedented human activities resulted in exponential increases in population, resource consumption, and pollutant emission. Recently, this latter period, known as the Great Acceleration, appears to be becoming the more widely accepted start date. To define any start point, a global stratigraphic marker or Global Boundary Stratotype Section and Point (GSSP) is typically required. Here, spheroidal carbonaceous fly ash particles (SCPs), byproducts of industrial fossil-fuel combustion, are proposed as a primary marker for a GSSP at the time of the Great Acceleration. Data from over 75 lake sediment records show a global, synchronous, and dramatic increase in particle accumulation starting in c. 1950 driven by the increased demand for electricity and the introduction of fuel-oil combustion, in addition to coal, as a means to produce it. SCPs are morphologically distinct and solely anthropogenic in origin, providing an unambiguous marker. This is a clear signal of great stratigraphic utility representing a primary driving force for global anthropogenic change.

  7. Summertime carbonaceous aerosols collected in the marine boundary layer of the Arctic Ocean

    Science.gov (United States)

    Xie, Zhouqing; Blum, Joel D.; Utsunomiya, Satoshi; Ewing, R. C.; Wang, Xinming; Sun, Liguang

    2007-01-01

    The chemistry, morphology, and microscale to nanoscale structures of carbonaceous aerosols from the marine boundary layer of the Arctic Ocean were investigated by a variety of electron microscopy techniques, including scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray spectroscopy (EDS). The relative levels of particles of black carbon (BC) were determined by electron paramagnetic resonance (EPR). Polycyclic aromatic hydrocarbons (PAHs) absorbed onto BC particles were extracted by the soxhlet extraction method and analyzed by gas chromatography mass spectrometry (GC-MS). The results show that the dominant particles of BC are char particles with spherical shape, porous structure, and high sulfur content, which are typically derived from residual oil combustion on ships. The spatial distribution of BC from ship emissions was found to be concentrated around the periphery of the Arctic Ocean, suggesting relatively intensive contamination by ships in the Russian and Canadian Arctic. The abundance of PAHs on BC particles ranges from 142 to 2672 pg/m3 (mean = 702 pg/m3), which is significantly higher than values previously measured by land-based observation. Thus we find that ship emissions are a potentially important contributor to the PAH levels at some locations in the Arctic Ocean during the summer.

  8. Optimizing Carbonaceous Nanostructure Composition as a Substrate to Grow Co Electrocatalysts

    Directory of Open Access Journals (Sweden)

    M Pourreza

    2018-02-01

    Full Text Available Global warming and other adverse environmental effects of fossil fuels have forced humans to consider clean and renewable energy resources. In this context, hydrogen production from water splitting reaction is a key approach. In order to reduce required overpotential for water oxidation reaction, it is necessary to use low cost and earth abundant electrocatalysts like Co, Cu, Fe, Mn, Ni and Zn nanostructures. Herein, cobalt nanostructures on steel-mesh substrate were applied. Electrochemical method was used for growth of Co nanoflakes because of its simplicity and scalability for commercial approach. On the other hand, using carbonaceous support layers including nanomaterials such as graphene and carbon nanotubes, can reduce overpotential and increase efficiency of the electrocatalyst.  According to the results, 40 wt% of graphene oxide and 60 wt% of carbon nanotubes in prepared carbon paste led to better growth for cobalt oxide nanoflakes. For the mentioned layer, cobalt was detected in metallic crystalline phase and the overpotential and electrical resistance measured 305 mV and 20 Ω, respectively.

  9. Catalytic conversion of carbohydrates into 5-hydroxymethylfurfural over cellulose-derived carbonaceous catalyst in ionic liquid.

    Science.gov (United States)

    Hu, Lei; Zhao, Geng; Tang, Xing; Wu, Zhen; Xu, Jiaxing; Lin, Lu; Liu, Shijie

    2013-11-01

    Three environmental-benign and low-cost carbon-based solid acid catalysts containing -SO3H, -COOH and phenolic -OH groups were prepared and used for the conversion of glucose into 5-hydroxymethylfurfural (HMF) in ionic liquid 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). The results demonstrated that cellulose-derived carbonaceous catalyst (CCC) possessed the highest catalytic activity, which resulted in 46.4% HMF yield at 160°C for only 15 min. In addition, the reaction kinetics for the conversion of glucose into HMF over CCC was fitted with the first-order rate equation. The slightly-deactivated CCC after four successive reaction runs could be easily regenerated by a simple carbonization and sulfonation process. More gratifyingly, the combination of CCC and [BMIM]Cl were confirmed to be suitable for converting other carbohydrates such as fructose, sucrose, maltose, cellobiose, starch and cellulose into HMF. Particularly, a plausible mechanism involving hydrolysis, isomerization and dehydration for the conversion of carbohydrates into HMF was also proposed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Carbonaceous anodes for lithium-ion batteries in combination with protic ionic liquids-based electrolytes

    Science.gov (United States)

    Menne, Sebastian; Schroeder, Matthias; Vogl, Thomas; Balducci, Andrea

    2014-11-01

    Protic ionic liquids (PILs) have been recently proposed as a new class of electrolytes for lithium-ion batteries (LIBs). So far, PILs-based electrolytes have been used in combination with several battery materials, but never with carbonaceous anodes. Since graphite is the state-of-the-art anode in LIBs, the use of PILs-based electrolyte in combination with this material appears of particular importance. In this work we showed, for the first time, that PILs-based electrolytes can be successfully used also in combination with graphite. Even if the lithium intercalation and deintercalation process of these electrode materials occur outside the ESW of PILs, the addition of film-forming additive makes possible the formation of a stable SEI and, consequently, the use of PILs-based electrolytes. The results of this study indicate that the performance of graphite electrode in PILs-based electrolytes is comparable, and even slightly higher, than that observed in AIL-based electrolytes.

  11. Cation-Pi Interaction: A Key Force for Sorption of Fluoroquinolone Antibiotics on Pyrogenic Carbonaceous Materials.

    Science.gov (United States)

    Zhao, Qing; Zhang, Siyu; Zhang, Xuejiao; Lei, Lei; Ma, Wei; Ma, Chuanxin; Song, Lei; Chen, Jingwen; Pan, Bo; Xing, Baoshan

    2017-12-05

    Cation-pi attraction is a major force that determines macromolecular structures and drug-receptor interactions. However, the role of the cation-pi interaction in sorption of fluoroquinolone antibiotics by pyrogenic carbonaceous materials (PCMs) has not been addressed. We studied sorption of ciprofloxacin (CIP) on graphite to quantify the contribution of the cation-pi interaction. Through competition experiments, the decreased amount of sorbed CIP by sequential treatment with hexadecane, phenanthrene and benzylamine represents the contribution of hydrophobic, pi-pi and cation-pi interactions, respectively. Benzylamine competed more strongly with CIP than n-hexadecane and phenanthrene, indicating that cation-pi is a major force. Cation-pi interactions accounted for up to 72.6% of the total sorption at an initial CIP concentration of 0.000015 mmol/L. Importantly, species transformation (CIP(0) captures H + from water to form CIP(+1)) induced by cation-pi interactions was verified both experimentally and theoretically and can be used to explain the environmental behavior of other fluoroquinolone antibiotics and biochemical processes of amino acids that interact with aromatic moieties. Because of the significant role of cation-pi interactions, CIP desorption increased up to 2.32 times when Na + increased from 0.01 mM to 0.45 mM, which is an environmentally relevant scenario at river estuaries. Hence, behaviors of fluoroquinolone antibiotics that are affected by ionic strength changes need to be carefully evaluated, especially in river estuaries.

  12. Pressurized reversible operation of a 30-cell solid oxide cell stack using carbonaceous gases

    DEFF Research Database (Denmark)

    Jensen, Søren Højgaard; Langnickel, Hendrik; Hintzen, N.

    2017-01-01

    Recent theoretical studies show that reversible electrochemical conversion of H2O and CO2 to CH4 inside pressurized solid oxide cells (SOCs) combined with subsurface storage of the produced gases can facilitate seasonal electricity storage with a round-trip efficiency reaching 70-80% and a storag...... in electrolysis mode. The degradation rates in both fuel cell and electrolysis mode were comparable to previously reported SOFCMAN stack degradation rates measured at ambient pressure operation with H2/H2O gas mixtures.......Recent theoretical studies show that reversible electrochemical conversion of H2O and CO2 to CH4 inside pressurized solid oxide cells (SOCs) combined with subsurface storage of the produced gases can facilitate seasonal electricity storage with a round-trip efficiency reaching 70-80% and a storage...... cost below 3 ¢/kWh. Here we show test results with a 30-cell SOFCMAN 301 stack operated with carbonaceous gases at 18.7 bar and 700 ˚C in both electrolysis and fuel cell mode. The CH4 content in the stack outlet gas increased from 0.22% at open circuit voltage (OCV) to 18% at -0.17 A cm-2...

  13. The Effect of Carbonaceous Reductant Selection on Chromite Pre-reduction

    Science.gov (United States)

    Kleynhans, E. L. J.; Beukes, J. P.; Van Zyl, P. G.; Bunt, J. R.; Nkosi, N. S. B.; Venter, M.

    2017-04-01

    Ferrochrome (FeCr) production is an energy-intensive process. Currently, the pelletized chromite pre-reduction process, also referred to as solid-state reduction of chromite, is most likely the FeCr production process with the lowest specific electricity consumption, i.e., MWh/t FeCr produced. In this study, the effects of carbonaceous reductant selection on chromite pre-reduction and cured pellet strength were investigated. Multiple linear regression analysis was employed to evaluate the effect of reductant characteristics on the aforementioned two parameters. This yielded mathematical solutions that can be used by FeCr producers to select reductants more optimally in future. Additionally, the results indicated that hydrogen (H)- (24 pct) and volatile content (45.8 pct) were the most significant contributors for predicting variance in pre-reduction and compressive strength, respectively. The role of H within this context is postulated to be linked to the ability of a reductant to release H that can induce reduction. Therefore, contrary to the current operational selection criteria, the authors believe that thermally untreated reductants ( e.g., anthracite, as opposed to coke or char), with volatile contents close to the currently applied specification (to ensure pellet strength), would be optimal, since it would maximize H content that would enhance pre-reduction.

  14. Oxygen isotopic relationships between the LEW85332 carbonaceous chondrite and CR chondrites

    Science.gov (United States)

    Prinz, M.; Weisberg, M. K.; Clayton, R. N.; Mayeda, T. K.

    1993-01-01

    LEW85332, originally described as a unique C3 chondrite, was shown to be a C2 chondrite with important linkages to the CR clan. An important petrologic aspect of LEW85332 is that it contains anhydrous chondrules and hydrated matrix, and new oxygen isotopic data on chondrules, matrix and whole rock are consistent with the petrology. Chondrules fall on the equilibrated chondrite line (ECL), with a slope near 1, which goes through ordinary chondrite chondrules. This contrasts with the CR chondrule line which has a lower slope due to hydrated components. LEW85332 chondrules define a new carbonaceous chondrite chondrule line, parallel to the anhydrous CV chondrule line (CCC), consistent with the well-established concept of two oxygen isotopic reservoirs. Matrix and whole rock fall on the CR line. The whole rock composition indicates that the chondrite is dominated by chondrules, and that most of them contain light oxygen similar to that of anhydrous olivine and pyroxene separates in the Renazzo and Al Rais CR chondrites.

  15. Hydrolysis of Selected Tropical Plant Wastes Catalyzed by a Magnetic Carbonaceous Acid with Microwave

    Science.gov (United States)

    Su, Tong-Chao; Fang, Zhen; Zhang, Fan; Luo, Jia; Li, Xing-Kang

    2015-12-01

    In this study, magnetic carbonaceous acids were synthesized by pyrolysis of the homogeneous mixtures of glucose and magnetic Fe3O4 nanoparticles, and subsequent sulfonation. The synthesis conditions were optimized to obtain a catalyst with both high acid density (0.75 mmol g-1) and strong magnetism [magnetic saturation, Ms = 19.5 Am2 kg-1]. The screened catalyst (C-SO3H/Fe3O4) was used to hydrolyze ball-milled cellulose in a microwave reactor with total reducing sugar (TRS) yield of 25.3% under the best conditions at 190 °C for 3.5 h. It was cycled for at least seven times with high catalyst recovery rate (92.8%), acid density (0.63 mmol g-1) and magnetism (Ms = 12.9 Am2 kg-1), as well as high TRS yield (20.1%) from the hydrolysis of ball-milled cellulose. The catalyst was further successfully tested for the hydrolysis of tropical biomass with high TRS and glucose yields of 79.8% and 58.3% for bagasse, 47.2% and 35.6% for Jatropha hulls, as well as 54.4% and 35.8% for Plukenetia hulls.

  16. Feasibility of Carbonaceous Nanomaterial-Assisted Photocatalysts Calcined at Different Temperatures for Indoor Air Applications

    Directory of Open Access Journals (Sweden)

    Wan-Kuen Jo

    2012-01-01

    Full Text Available This study examined the characteristics and photocatalytic activity of multiwall carbon nanotube-assisted TiO2 (MWNT-TiO2 nanocomposites calcined at different temperatures to assess their potential indoor air applications. It was confirmed that the composites calcined at low temperatures (300 and 400°C contained TiO2 nanoparticles bound intimately to the MWNT networks. Meanwhile, almost no MWNTs were observed when the calcination temperature was increased to 500 and 600°C. The MWNT-TiO2 composites calcined at low temperatures showed higher photocatalytic decomposition efficiencies for aromatic hydrocarbons at indoor concentrations than those calcined at high temperatures. The mean efficiencies for benzene, toluene, ethyl benzene, and o-xylene (BTEX by the composite calcined at 300°C were 32, 70, 79, and 79%, respectively, whereas they were 33, 71, 78, and 78% for the composite calcined at 400°C, respectively. In contrast, the efficiencies decreased to close to zero when the calcination temperature was increased to 600°C. Moreover, the MWNT-TiO2 exhibited superior photocatalytic performance for the decomposition efficiencies compared to TiO2 under conventional UV-lamp irradiations. Consequently, these carbonaceous nanomaterial-assisted photocatalysts can be applied effectively to indoor air applications depending upon the calcination temperature.

  17. Evaluation of the growth of carbonaceous deposit in steady state Tore Supra using infrared thermography

    International Nuclear Information System (INIS)

    Mitteau, R.; Guilhem, D.; Reichle, R.; Vallet, J.C.; Roche, H.; Buravand, Y.; Chantant, M.; Tsitrone, E.; Brosset, C.; Grosman, A.; Chappuis, P.

    2006-01-01

    Fusion devices with carbon as the main armour material are experiencing a growth in carbonaceous deposits at the surface of the plasma facing components. Tore Supra presents such deposits, and has specific features which influence their growth: long pulse operation and cooled walls. Deposits have a low thermal transfer to the cooled structure so that they appear as hot areas with the infrared imaging system looking at the elements surface temperature during plasma discharges. A 'degree of (carbon) deposit' on the toroidal pumped limiter is estimated by establishing the ratio between the apparent power on the limiter derived from the infrared measure and the actual one, deduced from a power balance analysis between the injected and the radiated power. This criterion is used to monitor the evolution of the deposit average thermal resistance. Successive shots have a similar 'degree of deposit', showing that the evaluation makes sense. Two years of data have been compiled (2003 and 2004), representing 3000 discharges (13 h of plasma, including 30 discharges longer than one minute). A three-fold increase in the 'degree of deposit' over six months is evidenced, following a limiter clean-up early in 2003. A comparison with calorimetric data produces a similar result, albeit less pronounced. Large steps in the degree of deposit are sometimes observed, usually correlated with identified events such as disruption, vessel opening, conditioning or plasma parameters change. It indicates that the deposit thermal resistance can change rapidly, although a systematic correlation with the above mentioned events could not be established

  18. Evaluation of the growth of carbonaceous deposit in steady state Tore Supra using infrared thermography

    Science.gov (United States)

    Mitteau, R.; Guilhem, D.; Reichle, R.; Vallet, J. C.; Roche, H.; Buravand, Y.; Chantant, M.; Tsitrone, E.; Brosset, C.; Grosman, A.; Chappuis, P.

    2006-03-01

    Fusion devices with carbon as the main armour material are experiencing a growth in carbonaceous deposits at the surface of the plasma facing components. Tore Supra presents such deposits, and has specific features which influence their growth: long pulse operation and cooled walls. Deposits have a low thermal transfer to the cooled structure so that they appear as hot areas with the infrared imaging system looking at the elements surface temperature during plasma discharges. A 'degree of (carbon) deposit' on the toroidal pumped limiter is estimated by establishing the ratio between the apparent power on the limiter derived from the infrared measure and the actual one, deduced from a power balance analysis between the injected and the radiated power. This criterion is used to monitor the evolution of the deposit average thermal resistance. Successive shots have a similar 'degree of deposit', showing that the evaluation makes sense. Two years of data have been compiled (2003 and 2004), representing 3000 discharges (13 h of plasma, including 30 discharges longer than one minute). A three-fold increase in the 'degree of deposit' over six months is evidenced, following a limiter clean-up early in 2003. A comparison with calorimetric data produces a similar result, albeit less pronounced. Large steps in the degree of deposit are sometimes observed, usually correlated with identified events such as disruption, vessel opening, conditioning or plasma parameters change. It indicates that the deposit thermal resistance can change rapidly, although a systematic correlation with the above mentioned events could not be established.

  19. Investigation of Redox Metal Oxides for Carbonaceous Fuel Conversion and CO2 Capture

    Science.gov (United States)

    Galinsky, Nathan Lee

    The chemical looping combustion (CLC) process uses metal oxides, also referred to as oxygen carriers, in a redox scheme for conversion of carbonaceous fuels into a concentrated stream of CO2 and steam while also producing heat and electricity. The unique redox scheme of CLC allows CO2 capture with minimal energy penalty. The CLC process performance greatly depends on the oxygen carrier that is chosen. To date, more than 1000 oxygen carriers have been developed for chemical-looping processes using metal oxides containing first-row transition metals. Oxygen carriers are typically mixed with an inert ceramic support to improve their overall mechanical stability and recyclability. This study focuses on design of (i) iron oxide oxygen carriers for conversion of gaseous carbonaceous fuels and (ii) development of perovskite CaMnO 3-d with improved stability and redox properties for conversion of solid fuels. Iron oxide is cheap and environmentally benign. However, it suffers from low activity with carbonaceous fuels due partially to the low ionic conductivity of iron oxides. In order to address the low activity of iron-oxide-based oxygen carriers, support addition has been shown to lower the energy barrier of oxygen anion transport within the oxygen carrier. This work adds a mixed-ionic-and-electronic-conductor (MIEC) support to iron oxide to help facilitate O2- transport inside the lattice of iron oxide. The MIEC-supported iron oxide is compared to commonly used supports including TiO2 and Al2O 3 and the pure ionic conductor support yttria-stabilized zirconia (YSZ) for conversion of different carbonaceous fuels and hydrogen. Results show that the MIEC-supported iron oxide exhibits up to 70 times higher activity than non-MIEC-supported iron oxides for methane conversion. The MIEC supported iron oxide also shows good recyclability with only minor agglomeration and carbon formation observed. The effect of support-iron oxide synergies is further investigated to understand

  20. The paleomagnetic record in carbonaceous chondrites - Natural remanence and magnetic properties

    Science.gov (United States)

    Brecher, A.; Arrhenius, G.

    1974-01-01

    Recent results of an intensive study of the natural remanence (NRM) and the magnetic properties of carbonaceous chondrites (CC) are summarized. It is convincingly demonstrated that the record of ancient magnetic fields has been preserved in these least-altered old samples of solar system material known. Intensities of specific NRM in the 13 meteorites surveyed span a broad range of values from 0.00005 to 0.5 emu/g. A low-temperature cleaning technique, based on the memory effect in magnetite grains, was followed by alternating field (af) demagnetization of the residual memory to exhibit the relative stability of NRM in the CC studied. No systematic correlation was found of either intensity or stability of NRM to af demagnetization with petrologic subtype, beyond a trend of increasing stability of memory from petrologic subtype C2 to subtype C4. The intensity and stability behavior of the saturation remanence are better suited for use in a magnetic classification of CC.

  1. Korzyści karmienia piersią dla matki

    Directory of Open Access Journals (Sweden)

    Magdalena Gibas-Dorna

    2012-12-01

    Full Text Available Powszechnie wiadomo, że karmienie piersią pozytywnie wpływa na zdrowie dziecka oraz jego rozwój intelek‑ tualny. światowa Organizacja Zdrowia (World Health Organization, WHO zaleca rozpoczęcie karmienia piersią od pierwszej godziny po porodzie i jego kontynuację przez okres co najmniej 6 miesięcy, a w miarę urozmaicania diety dziecka rekomenduje utrzymanie tego sposobu żywienia mniej więcej do 2. roku życia, traktując mleko matki jako najlepszy jakościowo pokarm uzupełniający. Coraz częściej podkreśla się protek‑ cyjną rolę karmienia naturalnego w rozwoju różnych chorób u matek oraz potencjalne skutki unikania prze‑ dłużonej laktacji. Wydaje się, że korzyści dla matki mają charakter wczesny (podczas połogu oraz długofa‑ lowy. Tuż po porodzie karmienie piersią przyspiesza obkurczanie macicy, zapobiega nadmiernej utracie krwi, chroni przed niedokrwistością z niedoboru żelaza, przeciwdziała wystąpieniu depresji poporodowej, umacnia więź matka – dziecko oraz poprawia zaburzoną w tym okresie jakość snu. Korzyści długofalowe wiążą się z obniżeniem ryzyka wystąpienia niektórych chorób nowotworowych (rak sutka, rak endometrium, rak jajni‑ ka, chorób sercowo‑naczyniowych (choroba niedokrwienna serca, nadciśnienie tętnicze, zaburzeń metabo‑ licznych (cukrzyca, nietolerancja glukozy, otyłość, hiperlipidemia, hiperinsulinemia, reumatoidalnego zapa‑ lenia stawów czy osteoporozy. Przedłużenie okresu laktacji i karmienia piersią ma również wymierną korzyść ekonomiczną i stanowi darmową naturalną antykoncepcję. Poniższa praca podsumowuje aktualny stan wie‑ dzy na temat wpływu karmienia piersią na zdrowie matek karmiących.

  2. Estudos de Comunidade e ciências sociais no Brasil

    Directory of Open Access Journals (Sweden)

    Nemuel da Silva Oliveira

    2011-12-01

    Full Text Available O objetivo deste artigo é fazer um balanço da literatura sobre os Estudos de Comunidade (EC no Brasil, destacando o contexto intelectual em que foram produzidos e os debates que suscitaram, especialmente entre as décadas de 1940 e 1960. Método de pesquisa em comunidades, oriundo da Antropologia, em investigações sobre o processo de mudança social, os EC estiveram em voga nos Estados Unidos entre os anos 1920 e 1950, tendo papel fundamental na institucionalização das Ciências Sociais no Brasil. Destacamos três aspectos na produção desses estudos no país, iniciando com uma abordagem conceitual: definições, origem e sua relação com temáticas marcantes nos anos 1950. Em seguida, privilegiamos os aspectos relacionados ao papel dos EC na história das Ciências Sociais no Brasil, com destaque para o processo de institucionalização das Ciências Sociais. Por fim, revisitamos os debates que tais estudos geraram entre os cientistas sociais quanto ao padrão de trabalho sociológico a ser desenvolvido naquele momento.The purpose of this article is to examine the literature about Community Studies(CS in Brazil, highlighting their intellectual context of production and the debates evoked by them, especially between the 1940's and 1960's. As a research method arising from Anthropology on communities in social change process, CS was used in United States between 1920's and 1950's, and played a fundamental role in the institutionalization of Social Sciences in Brazil. Three aspects are highlighted on CS production: first, in a conceptual approach, we discuss their definitions, origins and relation to main topics in the 1950's. The second aspect is related to the role of CS in the history of Social Sciences, especially their institutionalization process. By the end, we revisit the debates between social scientists about the sociological work standard to be developed at that time.

  3. Ciência da Computação

    Directory of Open Access Journals (Sweden)

    André Felipe Henriques Librantz

    2006-01-01

    Full Text Available Este trabalho apresenta um sistema de navegação autônoma de robôs construídos com kits Lego Mindstorms, para cálculo de trajetórias. Esse sistema pode ser utilizado como instrumento pedagógico multidisciplinar no curso de Ciência da Computação, uma vez que, para o seu desenvolvimento são necessários conhecimentos de algoritmos, linguagem de programação, lógica computacional, estrutura de dados, inteligência artificial (IA, redes de computadores, computação gráfica e robótica.

  4. Fazer ciência: o lugar do conceito

    Directory of Open Access Journals (Sweden)

    Wilton Garcia

    2007-06-01

    Full Text Available Este texto visa abrir uma discussão acerca da pesquisa contemporânea, investindo o enfoque no discurso científico para uma abordagem dinâmica de estratégias discursivas. Tento realizar uma reflexão crítica sobre a produção do saber em alguns procedimentos conceituais. Neste caso, remeto o olhar a uma consideração teórico-metodológica que pretende contribuir à atualização do discurso da ciência, hoje, e permita propor maior flexibilidade e deslocamento diante das diferentes produções de conhecimento. Este trabalho, portanto, não pretende expor, diretamente, idéias sobre ciência, mas sobre o discurso dito científico. Nesta investigação crítica, apresento sucintamente a noção de pós-(desconstrução. Utilizo os estudos contemporâneos como eixo teórico-metodológico para este desenvolvimento argumentativo. Os estudos contemporâneos pesquisam as atualizações de conceitos, que se organizam mediante a produção de atualidades e vasculham uma (redimensão teórica e política, associada ao sistema flexível da linguagem. Essas atualizações esboçam a área dos estudos contemporâneos em sua intensidade descritiva, quando aciona um olhar investigativo sobre as inovações no discurso científico, hoje.

  5. Removal of blue indigo and cadmium present in aqueous solutions using a modified zeolitic material and an activated carbonaceous material

    International Nuclear Information System (INIS)

    Gutierrez S, E. E.

    2011-01-01

    In the last years the use of water has been increased substantially, it has been also altered its quality as a result of human activities such as mining, industrial activities and others. Water pollution caused by dyes and heavy metals has adverse effects on the environment, since both pollutants are very persisten even after conventional treatments. Denim blue and cadmium are not biodegradable. There is a growing interest in finding new, efficient and low cost alternative materials to remove such pollutants from the aqueous medium. The purpose of this work was to evaluate a modified zeolitic tuff and an activated carbonaceous material obtained from the pyrolysis of sewage sludge for the removal of denim blue and cadmium. The zeolitic material was modified with Na + and Fe 3+ solutions to improve its sorption properties for the removal of cadmium and denim blue, respectively. Carbonaceous material was treated with 10% HCl solution to remove ashes. Both materials were characterized by scanning electron microscopy and elemental analysis (EDS), specific surface areas (Bet), thermogravimetric analysis, infrared spectroscopy and X-ray diffraction. Simultaneously, the denim blue dye was characterized by infrared spectroscopy and its pKa value was determined, these data allowed the determination of its chemical properties and its acid-base behavior in solution. In the content of this work the term indigo blue was changed by denim blue, as it corresponds to the commercial name of the dye. To assess the sorption capacity of sorbents, the sorption kinetics and sorption isotherms in batch system were determined; the results were fitted to mathematical models such as the pseudo-first order, pseudo second order and second order to describe the sorption kinetics and the Langmuir, Freundlich and Langmuir-Freundlich isotherms to describe sorption processes. The results show that the most efficient material to remove denim blue from aqueous solutions is the carbonaceous material

  6. Trophic analysis of the fish community in the Ciénega Churince, Cuatro Ciénegas, Coahuila

    Directory of Open Access Journals (Sweden)

    Ariana Hernández

    2017-09-01

    Full Text Available Fish diets were analyzed to evaluate the dynamic trophs of the fish community in the Churince wetland system of the Cuatro Ciénegas, where the fauna consists of nine species: endemic, native and introduced. In nine sampling events (between February 2011 and May 2014 556 specimens of all nine species were collected. Stomach contents were analyzed and the Relative Importance Index (IRI was calculated. The feed coefficient (Q of the diets and the accumulated trophic diversity (Hk, as well as the amplitude of the trophic niche were evaluated. Feeding strategies in the fish community were found to be eurifagic. The main foods in general were insects, crustaceans, gastropods, plants and teleosts. According to the average linkage method, four functional trophic groups were defined, with no higher consumption species; nevertheless all were regulators, mainly invertebrates. Therefore, the chain reaction in food control was higher from top to bottom, meaning a downwards dietary control.

  7. Ética, ciência e tecnologia

    Directory of Open Access Journals (Sweden)

    Ivan Domingues

    2004-06-01

    Full Text Available O artigo visa pensar a relação entre ética, ciência e tecnologia, enfatizando o problema de sua revinculação depois da cisão entre os juízos de fato e os juízos de valor, ocorrida no início dos tempos modernos. Uma vez examinada a ética da aristocracia guerreira e a moral do santo, procura-se delinear o caminho tomando como referência a ética da responsabilidade, cujo protótipo é a moral do sábio, desaparecido no curso dos tempos modernos, em razão da fragmentação do saber e do advento do especialista. Ao fim do estudo, é discutida a relação entre a ética e a metafísica, com o intuito de ajustar a questão antropológica à perspectiva cosmológica, bem como de fornecer as bases de um novo humanismo, objetivando a humanização da técnica e a geração de um novo homem, alfabetizado em ciência, tecnologia e humanidades.The article aims at thinking the relation among ethics, science and technology, emphasizing the problem of their re-tying, after the division into judgments of fact and judgments of value, wich happened in the begininning of modern times. Since the warlike aristocracy's ethics and the saint man's moral are examined, it tries to outline its way, taking as a reference the ethics of responsability, whose prototype is the wise man's moral, which disappeared in the course of modern times, due to the fragmentation of knowing and the advent of the specialist. At the end of the study, the relationship between ethics and metaphysics is discussed, aiming at adjusting the anthropological question to the cosmological perspective, as well as at providing the bases of a new humanism, objectifying the humanization of the technique and the generation of a new man, literate at science, technology and the humanities.

  8. Culturas das Ciências Naturais Cultures of Natural Sciences

    Directory of Open Access Journals (Sweden)

    Maria Margaret Lopes

    2005-12-01

    Full Text Available Este artigo apresenta subsídios para o ensino de História das Ciências, considerando particularmente o campo da História da História Natural e das Ciências Naturais. Sem ser uma revisão completa da historiografia desses campos de conhecimento sobre o mundo natural, retoma alguns traços gerais desses longos processos de definição de campos disciplinares que se configuram desde a Renascença até o final do século XVIII. Considera diversas tradições culturais e historiográficas que contribuíram para os nossos entendimentos atuais, de como a História Natural do Renascimento foi abandonando seus antigos quadros conceituais, assumindo novas práticas e se constituindo nas tradições da História Natural do século XVIII. Comenta esses processos, em que tanto a Botânica, a Zoologia, a Mineralogia se individualizam como áreas de conhecimentos apoiadas em práticas locais e coleções globais, indo além de sua subordinação à utilidade médica; bem como suas organizações em áreas de conhecimento, por começarem a se colocar questões relativas à origem e à historicidade dos seres e processos naturais, dados os avanços das temáticas classificatórias e das discussões envolvendo temporalidades.This paper provides insights into the teaching of the History of Science, especially the field of the History of Natural History and Natural Sciences. Although not claiming to be a complete historiographic review of these areas of knowledge about the natural world, it outlines the general traits of the long process of definition of disciplines that were shaped from the Renaissance to the end of the XVIII century. It encompasses various cultural and historiographic traditions that contributed to our present understanding of how Renaissance Natural History abandoned its ancient conceptual frameworks and assumed new practices and shaped itself in the tradition of XVIII century Natural History. The paper comments on these processes by which

  9. Sorption/desorption reversibility of polycyclic aromatic hydrocarbons (PAHs) in soils and carbonaceous materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guohui

    2008-07-01

    Understanding sorption/desorption is an important prerequisite for the prediction of fate and transport of pollutants in the environment. During the last two decades, numerous studies have reported hysteresis phenomenon for the interaction of hydrophobic organic contaminants (HOCs) with natural organic matter (NOM). It manifests as nonsingular sorption/desorption isotherms or different rates for sorption and desorption, where during desorption a higher affinity of a compound on a given sorbent and a longer time scale for release than for sorption is observed. Other studies showed that some of the reported sorption/desorption hysteresis phenomena are due to experimental artifacts, mainly resulting from non-attainment of sorption equilibrium before desorption experiments, which result in 'pseudo-hysteresis'. Except for the hypothesis of sorbent reconfiguration, clear experimental evidence for the physical or chemical mechanisms proposed to lead to hysteresis is still lacking. In this study, sorption/desorption equilibrium and kinetics of phenanthrene sorption/desorption from two soils and three carbonaceous samples were investigated using both batch and column techniques. The main objective of this work was to monitor hysteresis phenomenon by carefully recovering the solute mass in the system and to compare sorption/desorption equilibria and kinetics thermodynamically. Nonsingular isotherms and higher desorption enthalpies as well as increased activation energies with proceeding desorption are expected if significant hysteresis exists. Sorption-desorption cycles were carried out to compare equilibrium isotherms and associated sorption/desorption enthalpies (AeH, isosteric heats). Instead of the traditional decant-and-refill batch method, the experiments were conducted using a newly designed batch protocol, which enables the determination of sorption/desorption isotherms at different temperatures using a closed batch system. This method additionally allows

  10. Source apportionment of PM2.5 carbonaceous aerosol in Baghdad, Iraq

    Science.gov (United States)

    Hamad, Samera Hussein; Schauer, James Jay; Heo, Jongbae; Kadhim, Ahmed K. H.

    2015-04-01

    Baghdad is the second largest city in the Middle East and suffers from severe air quality degradation due to the high levels of the atmospheric particulate matter (PM). Limited information exists regarding the sources of PM in Baghdad, and the lack of information on sources inhibits the development of control strategies to reduce air pollution. To better understand the nature of fine particulate matter (PM2.5) in Baghdad and the Middle East, a one year sampling campaign to collect PM2.5 was conducted from September 2012 through September 2013, missing August 2013 samples due to the security situation. 24-hour integrated samples collected on a 1-in-6 day schedule were analyzed for the major components, and monthly average samples were analyzed by gas chromatography mass spectrometry (GCMS) methods to measure particle-phase organic molecular markers. The results of organic molecular markers were used in a chemical mass balance (CMB) model to quantify the sources of PM2.5 organic carbon (OC) and PM2.5 mass. Primary sources accounted for 44% of the measured PM2.5, and secondary sources were estimated to make up 28% of the measured PM2.5. Picene, a tracer of coal combustion detected in Baghdad where there is no evidence for coal combustion, can be attributed to burning crude oil and other low quality fuels in Baghdad. Source apportionment results showed that the dominant sources of the carbonaceous aerosols in Baghdad are gasoline (37 ± 6%) and diesel engines (17 ± 3%) which can be attributed to the extensive use of gasoline and diesel powered generators in Baghdad. Wood burning and residual oil combustion contributed to 5 ± 0.4 and 1 ± 0.2% respectively of OC. The unresolved sources contributed to 42 ± 19% of the OC which represented the secondary organic aerosol (SOA) and the unidentified sources.

  11. Occurrence of nitrogenous and carbonaceous disinfection byproducts in drinking water distributed in Shenzhen, China.

    Science.gov (United States)

    Huang, Huang; Zhu, Haihui; Gan, Wenhui; Chen, Xue; Yang, Xin

    2017-12-01

    A 12-month sampling program was conducted throughout a drinking water distribution system in Shenzhen and the data from 251 samples provide a comprehensive picture of the spatial and seasonal variability of 17 species disinfection by-products (DBPs) in a city with subtropical monsoon climate. The carbonaceous disinfection by-product (C-DBPs) included four trihalomethanes (THMs), three trihaloacetaldehydes (THAs) and two haloketones (HKs). Their median concentrations over the entire period were 19.9 μg/L, 3.4 μg/L and 1.4 μg/L, respectively. The nitrogenous DBPs (N-DBPs) monitored were four haloacetonitriles (HANs) and four haloacetamides (HAcAms). Their median levels were 2.0 μg/L and 1.5 μg/L, respectively. Low levels of brominated DBP species (bromine substitution factors ≤ 0.5) were observed. The BSF of each DBP class followed the trend: THMs ≈ DHAcAms > DHANs > THAs. All the DBP concentrations showed clear seasonal variations with the highest average concentrations in spring. Correlation analyses showed that the THMs and CH levels in Shenzhen drinking water could be used as statistical indicators of the levels of unregulated N-DBPs (0.4 water in China, and provide an important reference data set for DBP occurrence in cities with a subtropical monsoon climate around the world. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES

    Directory of Open Access Journals (Sweden)

    R. A. Zaveri

    2012-08-01

    Full Text Available Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE Atmospheric Radiation Measurement (ARM program's Carbonaceous Aerosol and Radiative Effects Study (CARES carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites – one within the Sacramento urban area and another about 40 km to the northeast in the foothills area – were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and "aged" urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: (a the scientific background and motivation for the study, (b the operational and logistical information pertinent to the execution of the study, (c an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and (d a roadmap

  13. Sorption interactions of biochars and pyrogenic carbonaceous materials with anionic contaminants

    Science.gov (United States)

    Fristak, Vladimir; Moreno-Jimenez, Eduardo; Micháleková-Richveisová, Barbora; Schmidt, Hans-Peter; Bucheli, Thomas; Soja, Gerhard

    2016-04-01

    Biochar as a highly porous and carbon-rich material with a large surface area is a new player in the system of environmental remediation techniques. A wide range of valuable sorption properties of this carbonaceous pyrolysis product provides new options to solve contaminant problems in soil and water and thus may reduce the number of contaminated sites. The sorption capacity of agricultural wastes and wood processing-derived biochars has been found to be excellent due to high surface area, pore volume, and surface functional groups. However, sorption interactions and separation of xenobiotics from waste water, soil solutions or polluted surface water is very often affected by the concentration of contaminant, contact time, effects of competitive substances and mainly by the chemical form of the respective contaminant. The negative surface charge of biochar-based sorption materials supports significant sorption in particular for cationic forms of pollutants. On the other hand many environmentally critical substances occur in anionic forms (e.g. As, P, Mo, Tc). Therefore their retention and immobilization by biochar is frequently considered as problematic or limited. Besides, details about the mechanism of biochar interactions with anionic compounds and the options for surface modification are largely unexplored. This contribution presents a comparative study about production and characterization of unmodified, chemically pre-treated and post-treated biochars with respect to sorption processes of model anionic compounds (PO43-, AsO43-). The obtained results confirmed the crucial role of altering biochar properties (pH) and of surface modification for improving biochar sorption efficiency for anionic contaminants.

  14. Preparation and properties of carbonaceous products prepared by the cracking of natural gas

    International Nuclear Information System (INIS)

    Blum, P.L.; Bochirol, L.; Rappeneau, J.; Cornuault, P.; Blanchard, R.; Moreau, C.

    1964-01-01

    Complete results are presented of tests recently carried out at the Grenoble Nuclear Research Centre in an attempt to transform natural gas (gas from Lacq), used as a source of pyrolytic carbon, into carbonaceous products with improved properties. Several methods have been studied: 1 - By using normal grade industrial graphite as support (density of about 1.50) products having densities of about 1.80 are obtained. Their open porosity (6 to 7 per cent) is lower than that of conventional graphites, and several of their characteristics are more or less equal to, or better than those obtained from a double impregnation witch pitch. 2 - The use as supporting material of the semi-products ('cooked') usually used for graphite production does not lead to satisfactory results. The main reasons for this are given. 3 - A new process, called 'BB5', has been developed. The starting materials here are powdered products (petrol coke or graphite) which are put into shape with the use of a binder which can be dispersed in water. The supports thus produced make it possible, because of their porous structure, to make the most of the densification produced by cracking natural gas below 1000 deg. C. The products obtained, which are made up of equal amounts approximately of the supporting material and of pyrocarbon can attain densities of over 1.90. Their very low open porosity can be reduced almost to zero and their impermeability is then excellent (k=10 -8 cm 2 sec -1 ). They have also a remarkably high resistance to compression, values of 15 to 20 kg/mm 2 being obtained for those carbons which have not undergone a final graphitization treatment. Some examples are given of possible nuclear applications of the materials produced in this manner. (authors) [fr

  15. Sources and characteristics of carbonaceous aerosol in two largest cities in Pearl River Delta Region, China

    Science.gov (United States)

    Duan, Jingchun; Tan, Jihua; Cheng, Dingxi; Bi, Xinhui; Deng, Wenjing; Sheng, Guoying; Fu, Jiamo; Wong, M. H.

    PM 2.5 samples were collected at five sites in Guangzhou and Hong Kong, Pearl River Delta Region (PRDR), China in both summer and winter during 2004-2005. Elemental carbon (EC) and organic carbon (OC) in these samples were measured. The OC and EC concentrations ranked in the order of urban Guangzhou > urban Hong Kong > background Hong Kong. Total carbonaceous aerosol (TCA) contributed less to PM 2.5 in urban Guangzhou (32-35%) than that in urban Hong Kong (43-57%). The reason may be that, as an major industrial city in South China, Guangzhou would receive large amount of inorganic aerosol from all kinds of industries, however, as a trade center and seaport, urban Hong Kong would mainly receive organic aerosol and EC from container vessels and heavy-duty diesel trucks. At Hong Kong background site Hok Tsui, relatively lower contribution of TCA to PM 2.5 may result from contributions of marine inorganic aerosol and inland China pollutant. Strong correlation ( R2=0.76-0.83) between OC and EC indicates minor fluctuation of emission and the secondary organic aerosol (SOA) formation in urban Guangzhou. Weak correlation between OC and EC in Hong Kong can be related to the impact of the long-range transported aerosol from inland China. Averagely, secondary OC (SOC) concentrations were 3.8-5.9 and 10.2-12.8 μg m -3, respectively, accounting for 21-32% and 36-42% of OC in summer and winter in Guangzhou. The average values of 4.2-6.8% for SOA/ PM 2.5 indicate that SOA was minor component in PM 2.5 in Guangzhou.

  16. Organic composition of carbonaceous aerosols in an aged prescribed fire plume

    Science.gov (United States)

    Yan, B.; Zheng, M.; Hu, Y. T.; Lee, S.; Kim, H. K.; Russell, A. G.

    2008-11-01

    Aged smoke from a prescribed fire (dominated by conifers) impacted Atlanta, GA on 28 February 2007 and dramatically increased hourly ambient concentrations of PM2.5 and organic carbon (OC) up to 140 and 72 μg m-3, respectively. It was estimated that over 1 million residents were exposed to the smoky air lasting from the late afternoon to midnight. To better understand the processes impacting the aging of fire plumes, a detailed chemical speciation of carbonaceous aerosols was conducted by gas chromatography/mass spectrometry (GC/MS) analysis. Ambient concentrations of many organic species (levoglucosan, resin acids, retene, n-alkanes and n-alkanoic acids) associated with wood burning emission were significantly elevated on the event day. Levoglucosan increased by a factor of 10, while hopanes, steranes, cholesterol and major polycyclic aromatic hydrocarbons (PAHs) did not show obvious increases. Strong odd over even carbon number predominance was found for n-alkanes versus even over odd predominance for n-alkanoic acids. Alteration of resin acids during transport from burning sites to monitors is suggested by the observations. Our study also suggests that large quantities of biogenic volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) were released both as products of combustion and unburned vegetation heated by the fire. Higher leaf temperature can stimulate biogenic VOC and SVOC emissions, which enhanced formation of secondary organic aerosols (SOA) in the atmosphere. This is supported by elevated ambient concentrations of secondary organic tracers (dicarboxylic acids, 2-methyltetrols, pinonic acid and pinic acid). An approximate source profile was built for the aged fire plume to help better understand evolution of wood smoke emission and for use in source impact assessment.

  17. Organic composition of carbonaceous aerosols in an aged prescribed fire plume

    Science.gov (United States)

    Yan, B.; Zheng, M.; Hu, Y. T.; Lee, S.; Kim, H. K.; Russell, A. G.

    2007-12-01

    Aged smoke from a prescribed fire (dominated by conifers) impacted Atlanta, GA on 28 February 2007 and dramatically increased hourly ambient concentrations of PM2.5 and organic carbon (OC) up to 140 and 72 μg m-3, respectively. It was estimated that over 1 million residents were exposed to the smoky air lasting from the late afternoon to midnight. To better understand the processes impacting the aging of fire plumes, a detailed chemical speciation of carbonaceous aerosols was conducted by gas chromatography/mass spectrometry (GC/MS) analysis. Ambient concentrations of many organic species (levoglucosan, resin acids, retene, n-alkanes, n-alkanoic acids) associated with wood burning emission were significantly elevated on the event day. Levoglucosan increased by a factor of 10, while hopanes, steranes, cholesterol and major polycyclic aromatic hydrocarbons (PAHs) did not show obvious increases. Strong odd over even carbon number predominance was found for n-alkanes versus even over odd predominance for n-alkanoic acids. Alteration of resin acids during transport from burning sites to monitors is suggested by the observations. Our study also suggests that large quantities of biogenic volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) were released both as products of combustion and unburned vegetation heated by the fire. Higher leaf temperature can stimulate biogenic VOC and SVOC emissions, which enhanced formation of secondary organic aerosols (SOA) in the atmosphere. This is supported by elevated ambient concentrations of secondary organic tracers (dicarboxylic acids, 2-methyltetrols, pinonic acid and pinic acid). An approximate source profile was built for the aged fire plume to help better understand evolution of wood smoke emission and can be used for source apportionment.

  18. A global modeling study on carbonaceous aerosol microphysical characteristics and radiative effects

    Directory of Open Access Journals (Sweden)

    S. E. Bauer

    2010-08-01

    Full Text Available Recently, attention has been drawn towards black carbon aerosols as a short-term climate warming mitigation candidate. However the global and regional impacts of the direct, indirect and semi-direct aerosol effects are highly uncertain, due to the complex nature of aerosol evolution and the way that mixed, aged aerosols interact with clouds and radiation. A detailed aerosol microphysical scheme, MATRIX, embedded within the GISS climate model is used in this study to present a quantitative assessment of the impact of microphysical processes involving black carbon, such as emission size distributions and optical properties on aerosol cloud activation and radiative effects.

    Our best estimate for net direct and indirect aerosol radiative flux change between 1750 and 2000 is −0.56 W/m2. However, the direct and indirect aerosol effects are quite sensitive to the black and organic carbon size distribution and consequential mixing state. The net radiative flux change can vary between −0.32 to −0.75 W/m2 depending on these carbonaceous particle properties at emission. Taking into account internally mixed black carbon particles let us simulate correct aerosol absorption. Absorption of black carbon aerosols is amplified by sulfate and nitrate coatings and, even more strongly, by organic coatings. Black carbon mitigation scenarios generally showed reduced radiative fluxeswhen sources with a large proportion of black carbon, such as diesel, are reduced; however reducing sources with a larger organic carbon component as well, such as bio-fuels, does not necessarily lead to a reduction in positive radiative flux.

  19. A Global Modeling Study on Carbonaceous Aerosol Microphysical Characteristics and Radiative Effects

    Science.gov (United States)

    Bauer, S. E.; Menon, S.; Koch, D.; Bond, T. C.; Tsigaridis, K.

    2010-01-01

    Recently, attention has been drawn towards black carbon aerosols as a short-term climate warming mitigation candidate. However the global and regional impacts of the direct, indirect and semi-direct aerosol effects are highly uncertain, due to the complex nature of aerosol evolution and the way that mixed, aged aerosols interact with clouds and radiation. A detailed aerosol microphysical scheme, MATRIX, embedded within the GISS climate model is used in this study to present a quantitative assessment of the impact of microphysical processes involving black carbon, such as emission size distributions and optical properties on aerosol cloud activation and radiative effects. Our best estimate for net direct and indirect aerosol radiative flux change between 1750 and 2000 is -0.56 W/m2. However, the direct and indirect aerosol effects are quite sensitive to the black and organic carbon size distribution and consequential mixing state. The net radiative flux change can vary between -0.32 to -0.75 W/m2 depending on these carbonaceous particle properties at emission. Taking into account internally mixed black carbon particles let us simulate correct aerosol absorption. Absorption of black carbon aerosols is amplified by sulfate and nitrate coatings and, even more strongly, by organic coatings. Black carbon mitigation scenarios generally showed reduced radiative fluxeswhen sources with a large proportion of black carbon, such as diesel, are reduced; however reducing sources with a larger organic carbon component as well, such as bio-fuels, does not necessarily lead to a reduction in positive radiative flux.

  20. GlidArc-assisted production of synthesis gas from various carbonaceous feedstocks

    International Nuclear Information System (INIS)

    Czernichowski, A.; Czernichowski, P.; Czernichowski, M.

    2003-01-01

    Pure Hydrogen or its mixture with Carbon Monoxide (called Synthesis Gas) will be massively extracted from various fossil or renewable feedstocks. Such matters contain contaminants (principally Sulphur) that make conventional catalytic reforming technologies very difficult to run without a prior deep cleaning of the feeds in order to avoid the reformer's catalyst poisoning. We propose a non-catalytic process in which almost any carbonaceous feed is converted into the Synthesis Gas in a presence of high-voltage discharges (called GlidArc) that assist the exothermic Partial Oxidation POX). The unique oxidant is air. This contribution presents some of our tests with natural gas, cyclohexane, heptane, toluene, various gasolines, and various diesel oils (including logistic ones). In two separate contributions to this Conference we present our more expanded studies on the GlidArc-assisted POX reforming of commercial propane and rapeseed oil (canola). Our reactors (1- or 2-Liter scale) work at atmospheric pressure and need less than 0.5 kW electric power (rather about 0.1 kW) to produce up to 9 m 3 (n)/h of Nitrogen-diluted SynGas containing up to 27% of H 2 and up to 23% of CO. Such assisting power represents roughly less than 5% (rather around 2%) with respect to the Lower Heating Value of produced Synthesis Gas (up to 11 kW). Recycling such relatively small portion of the power is an acceptable compromise. All tested feeds are totally reformed. No soot is observed at a sufficient O/C ratio. (author)

  1. Morphological preservation of carbonaceous plant fossils in blueschist metamorphic rocks from New Zealand.

    Science.gov (United States)

    Galvez, M E; Beyssac, O; Benzerara, K; Bernard, S; Menguy, N; Cox, S C; Martinez, I; Johnston, M R; Brown, G E

    2012-03-01

    Morphological and chemical evidence of ancient life is widespread in sedimentary rocks retrieved from shallow depths in the Earth's crust. Metamorphism is highly detrimental to the preservation of biological information in rocks, thus limiting the geological record in which traces of life might be found. Deformation and increasing pressure/temperature during deep burial may alter the morphology as well as the composition and structure of both the organic and mineral constituents of fossils. However, microspore fossils have been previously observed in intensely metamorphosed rocks. It has been suggested that their small size, and/or the nature of the polymer composing their wall, and/or the mineralogy of their surrounding matrix were key parameters explaining their exceptional preservation. Here, we describe the remarkable morphological preservation of plant macrofossils in blueschist metamorphic rocks from New Zealand containing lawsonite. Leaves and stems can be easily identified at the macroscale. At the microscale, polygonal structures with walls mineralized by micas within the leaf midribs and blades may derive from the original cellular ultrastructure or, alternatively, from the shrinkage during burial of the gelified remnants of the leaves in an abiotic process. Processes and important parameters involved in the remarkable preservation of these fossils during metamorphism are discussed. Despite the excellent morphological preservation, the initial biological polymers have been completely transformed to graphitic carbonaceous matter down to the nanometer scale. This occurrence demonstrates that plant macrofossils may experience major geodynamic processes such as metamorphism and exhumation involving deep changes and homogenization of their carbon chemistry and structure but still retain their morphology with remarkable integrity even if they are not shielded by any hard-mineralized concretion. © 2012 Blackwell Publishing Ltd.

  2. Carbonaceous Chondrite Meteorites: the Chronicle of a Potential Evolutionary Path between Stars and Life.

    Science.gov (United States)

    Pizzarello, Sandra; Shock, Everett

    2017-09-01

    The biogenic elements, H, C, N, O, P and S, have a long cosmic history, whose evolution can still be observed in diverse locales of the known universe, from interstellar clouds of gas and dust, to pre-stellar cores, nebulas, protoplanetary discs, planets and planetesimals. The best analytical window into this cosmochemical evolution as it neared Earth has been provided so far by the small bodies of the Solar System, some of which were not significantly altered by the high gravitational pressures and temperatures that accompanied the formation of larger planets and may carry a pristine record of early nebular chemistry. Asteroids have delivered such records, as their fragments reach the Earth frequently and become available for laboratory analyses. The Carbonaceous Chondrite meteorites (CC) are a group of such fragments with the further distinction of containing abundant organic materials with structures as diverse as kerogen-like macromolecules and simpler compounds with identical counterparts in Earth's biosphere. All have revealed a lineage to cosmochemical synthetic regimes. Several CC show that asteroids underwent aqueous alteration of their minerals or rock metamorphism but may yet yield clues to the reactivity of organic compounds during parent-body processes, on asteroids as well as larger ocean worlds and planets. Whether the exogenous delivery by meteorites held an advantage in Earth's molecular evolution remains an open question as many others regarding the origins of life are. Nonetheless, the natural samples of meteorites allow exploring the physical and chemical processes that might have led to a selected chemical pool amenable to the onset of life. Graphical Abstract ᅟ.

  3. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)

    Science.gov (United States)

    Zaveri, R. A.; Shaw, W. J.; Cziczo, D. J.; Schmid, B.; Ferrare, R. A.; Alexander, M. L.; Alexandrov, M.; Alvarez, R. J.; Arnott, W. P.; Atkinson, D. B.; Baidar, S.; Banta, R. M.; Barnard, J. C.; Beranek, J.; Berg, L. K.; Brechtel, F.; Brewer, W. A.; Cahill, J. F.; Cairns, B.; Cappa, C. D.; Chand, D.; China, S.; Comstock, J. M.; Dubey, M. K.; Easter, R. C.; Erickson, M. H.; Fast, J. D.; Floerchinger, C.; Flowers, B. A.; Fortner, E.; Gaffney, J. S.; Gilles, M. K.; Gorkowski, K.; Gustafson, W. I.; Gyawali, M.; Hair, J.; Hardesty, R. M.; Harworth, J. W.; Herndon, S.; Hiranuma, N.; Hostetler, C.; Hubbe, J. M.; Jayne, J. T.; Jeong, H.; Jobson, B. T.; Kassianov, E. I.; Kleinman, L. I.; Kluzek, C.; Knighton, B.; Kolesar, K. R.; Kuang, C.; Kubátová, A.; Langford, A. O.; Laskin, A.; Laulainen, N.; Marchbanks, R. D.; Mazzoleni, C.; Mei, F.; Moffet, R. C.; Nelson, D.; Obland, M. D.; Oetjen, H.; Onasch, T. B.; Ortega, I.; Ottaviani, M.; Pekour, M.; Prather, K. A.; Radney, J. G.; Rogers, R. R.; Sandberg, S. P.; Sedlacek, A.; Senff, C. J.; Senum, G.; Setyan, A.; Shilling, J. E.; Shrivastava, M.; Song, C.; Springston, S. R.; Subramanian, R.; Suski, K.; Tomlinson, J.; Volkamer, R.; Wallace, H. W.; Wang, J.; Weickmann, A. M.; Worsnop, D. R.; Yu, X.-Y.; Zelenyuk, A.; Zhang, Q.

    2012-08-01

    Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program's Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites - one within the Sacramento urban area and another about 40 km to the northeast in the foothills area - were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and "aged" urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: (a) the scientific background and motivation for the study, (b) the operational and logistical information pertinent to the execution of the study, (c) an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and (d) a roadmap of planned data

  4. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)

    Energy Technology Data Exchange (ETDEWEB)

    Zaveri, R. A.; Shaw, W. J.; Cziczo, D. J.; Schmid, B.; Ferrare, R. A.; Alexander, M. L.; Alexandrov, M.; Alvarez, R. J.; Arnott, W. P.; Atkinson, D. B.; Baidar, S.; Banta, R. M.; Barnard, J. C.; Beranek, J.; Berg, L. K.; Brechtel, F.; Brewer, W. A.; Cahill, J. F.; Cairns, B.; Cappa, C. D.; Chand, D.; China, S.; Comstock, J. M.; Dubey, M. K.; Easter, R. C.; Erickson, M. H.; Fast, J. D.; Floerchinger, C.; Flowers, B. A.; Fortner, E.; Gaffney, J. S.; Gilles, M. K.; Gorkowski, K.; Gustafson, W. I.; Gyawali, M.; Hair, J.; Hardesty, R. M.; Harworth, J. W.; Herndon, S.; Hiranuma, N.; Hostetler, C.; Hubbe, J. M.; Jayne, J. T.; Jeong, H.; Jobson, B. T.; Kassianov, E. I.; Kleinman, L. I.; Kluzek, C.; Knighton, B.; Kolesar, K. R.; Kuang, C.; Kubátová, A.; Langford, A. O.; Laskin, A.; Laulainen, N.; Marchbanks, R. D.; Mazzoleni, C.; Mei, F.; Moffet, R. C.; Nelson, D.; Obland, M. D.; Oetjen, H.; Onasch, T. B.; Ortega, I.; Ottaviani, M.; Pekour, M.; Prather, K. A.; Radney, J. G.; Rogers, R. R.; Sandberg, S. P.; Sedlacek, A.; Senff, C. J.; Senum, G.; Setyan, A.; Shilling, J. E.; Shrivastava, M.; Song, C.; Springston, S. R.; Subramanian, R.; Suski, K.; Tomlinson, J.; Volkamer, R.; Wallace, H. W.; Wang, J.; Weickmann, A. M.; Worsnop, D. R.; Yu, X. -Y.; Zelenyuk, A.; Zhang, Q.

    2012-01-01

    Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program’s Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites – one within the Sacramento urban area and another about 40 km to the northeast in the foothills area – were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climate-related properties in freshly polluted and “aged” urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: a) the scientific background and motivation for the study, b) the operational and logistical information pertinent to the execution of the study, c) an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and d) a roadmap of

  5. Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)

    Science.gov (United States)

    Zaveri, R. A.; Shaw, W. J.; Cahill, J. F.; Cairns, Brian; Cappa, C. D.; Ottaviani, Matteo; Cziczo, D. J.; Ferrare, Richard A.; Alexander, M. L.; Alexandrov, Mikhail Dmitrievic; hide

    2012-01-01

    Substantial uncertainties still exist in the scientific understanding of the possible interactions between urban and natural (biogenic) emissions in the production and transformation of atmospheric aerosol and the resulting impact on climate change. The US Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program's Carbonaceous Aerosol and Radiative Effects Study (CARES) carried out in June 2010 in Central Valley, California, was a comprehensive effort designed to improve this understanding. The primary objective of the field study was to investigate the evolution of secondary organic and black carbon aerosols and their climate-related properties in the Sacramento urban plume as it was routinely transported into the forested Sierra Nevada foothills area. Urban aerosols and trace gases experienced significant physical and chemical transformations as they mixed with the reactive biogenic hydrocarbons emitted from the forest. Two heavily-instrumented ground sites - one within the Sacramento urban area and another about 40 km to the northeast in the foothills area - were set up to characterize the evolution of meteorological variables, trace gases, aerosol precursors, aerosol size, composition, and climaterelated properties in freshly polluted and "aged" urban air. On selected days, the DOE G-1 aircraft was deployed to make similar measurements upwind and across the evolving Sacramento plume in the morning and again in the afternoon. The NASA B-200 aircraft, carrying remote sensing instruments, was also deployed to characterize the vertical and horizontal distribution of aerosols and aerosol optical properties within and around the plume. This overview provides: (a) the scientific background and motivation for the study, (b) the operational and logistical information pertinent to the execution of the study, (c) an overview of key observations and initial findings from the aircraft and ground-based sampling platforms, and (d) a roadmap of planned data

  6. Determination of primary and secondary sources of organic acids and carbonaceous aerosols using stable carbon isotopes

    Science.gov (United States)

    Fisseha, Rebeka; Saurer, Matthias; Jäggi, Maya; Siegwolf, Rolf T. W.; Dommen, Josef; Szidat, Sönke; Samburova, Vera; Baltensperger, Urs

    Stable carbon isotope ratio ( δ13C) data can provide important information regarding the sources and the processing of atmospheric organic carbon species. Formic, acetic and oxalic acid were collected from Zurich city in August-September 2002 and March 2003 in the gas and aerosol phase, and the corresponding δ13C analysis was performed using a wet oxidation method followed by isotope ratio mass spectrometry. In August, the δ13C values of gas phase formic acid showed a significant correlation with ozone (coefficient of determination ( r2) = 0.63) due to the kinetic isotope effect (KIE). This indicates the presence of secondary sources (i.e. production of organic acids in the atmosphere) in addition to direct emission. In March, both gaseous formic and acetic acid exhibited similar δ13C values and did not show any correlation with ozone, indicating a predominantly primary origin. Even though oxalic acid is mainly produced by secondary processes, the δ13C value of particulate oxalic acid was not depleted and did not show any correlation with ozone, which may be due to the enrichment of 13C during the gas - aerosol partitioning. The concentrations and δ13C values of the different aerosol fractions (water soluble organic carbon, water insoluble organic carbon, carbonate and black carbon) collected during the same period were also determined. Water soluble organic carbon (WSOC) contributed about 60% to the total carbon and was enriched in 13C compared to other fractions indicating a possible effect of gas - aerosol partitioning on δ13C of carbonaceous aerosols. The carbonate fraction in general was very low (3% of the total carbon).

  7. Carbonaceous Chondrite Meteorites: the Chronicle of a Potential Evolutionary Path between Stars and Life

    Science.gov (United States)

    Pizzarello, Sandra; Shock, Everett

    2017-09-01

    The biogenic elements, H, C, N, O, P and S, have a long cosmic history, whose evolution can still be observed in diverse locales of the known universe, from interstellar clouds of gas and dust, to pre-stellar cores, nebulas, protoplanetary discs, planets and planetesimals. The best analytical window into this cosmochemical evolution as it neared Earth has been provided so far by the small bodies of the Solar System, some of which were not significantly altered by the high gravitational pressures and temperatures that accompanied the formation of larger planets and may carry a pristine record of early nebular chemistry. Asteroids have delivered such records, as their fragments reach the Earth frequently and become available for laboratory analyses. The Carbonaceous Chondrite meteorites (CC) are a group of such fragments with the further distinction of containing abundant organic materials with structures as diverse as kerogen-like macromolecules and simpler compounds with identical counterparts in Earth's biosphere. All have revealed a lineage to cosmochemical synthetic regimes. Several CC show that asteroids underwent aqueous alteration of their minerals or rock metamorphism but may yet yield clues to the reactivity of organic compounds during parent-body processes, on asteroids as well as larger ocean worlds and planets. Whether the exogenous delivery by meteorites held an advantage in Earth's molecular evolution remains an open question as many others regarding the origins of life are. Nonetheless, the natural samples of meteorites allow exploring the physical and chemical processes that might have led to a selected chemical pool amenable to the onset of life. [Figure not available: see fulltext.

  8. Variações sobre arte e ciência

    Directory of Open Access Journals (Sweden)

    Octavio Ianni

    2004-06-01

    Full Text Available O texto propõe aproximações entre ciência e arte por meio de contrastes e semelhanças reconhecíveis nessas modalidades discursivas de conhecimento, como linguagens e narrativas singulares, dotadas de características próprias, mas que freqüentemente se valem de procedimentos e recursos alheios. Busca salientar tanto os usos de recursos ficcionais pelos textos científicos, como o contrário, as valências cognitivas e mesmo a reconstrução complexa de experiências sociais pelos textos literários, articulados por uma ambição estética.The text establishes connections between science and art through the contrasts and similarities traceables in those discourses of knowledge, while languages and peculiar narratives endowed with its own traits, but that quite often appeal to alien proce-dures and resources. It seeks to point out the uses of fiction resources in scientific texts, as the opposite, the cognitives assets and even the complex reconstruction of social experiences found out literary texts, moved by an aesthetic ambition.

  9. B[e] Star CI Cam: Eighteen Years of Research

    Science.gov (United States)

    Goranskij, V. P.; Barsukova, E. A.; Bjorkman, K. S.; Burenkov, A. N.; Klochkova, V. G.; Manset, N.; Metlova, N. V.; Miroshnichenko, A. S.; Panchuk, V. E.; Yushkin, M. V.; Zharikov, S. V.

    2017-02-01

    We present the results of extensive spectroscopic and photometric observations of CI Cam performed after its outburst in April 1998. The outburst was interpreted as a thermonuclear runaway of hydrogen on the surface of a white dwarf (WD). We detected variations of both the brightness and the He II 4686 Å line radial velocity with a period of 19d.400±0d.015 due to orbital motion of the WD. The rapid brightness variations on a timescale of hours is explained by pulsations of a B4 III-V[e] star. In 2012, the system entered an active state with the stronger He II line and with the brightness increased by 0.4 mag. We observed a slow low-amplitude drift in the velocity of Fe II and [N II] emission lines which we explained by the orbital motion of the B[e] star + WD system along with all its gaseous environment around a third companion invisible in the spectra. The active phase of the B[e] star might have been initiated by a close approach of the binary and the third companion in 2007.

  10. Cientometria: a métrica da ciência

    Directory of Open Access Journals (Sweden)

    José Aparecido da Silva

    2001-01-01

    Full Text Available Cientometria é definida como o estudo da mensuração e quantificação do progresso científico, estando a pesquisa baseada em indicadores bibliométricos. A cientometria tem um grande potencial de aplicação, havendo interesse de Governos e instituições de pesquisas em utilizar este conhecimento com o objetivo de implementar diferentes formas de apoio ao desenvolvimento científico e tecnológico. Nos últimos tempos, também, ela tem sido usada para ajudar nações a tomarem decisões sobre quais áreas do saber necessitam de fundos especiais; além disso, a análise das citações ou dos fatores de impacto de periódicos e artigos vem se tornando uma fonte importante de informação para historiadores, sociólogos e outros pesquisadores interessados na evolução da ciência. Este artigo focaliza como diferentes indicadores de citação tornam possível verificar tanto a evolução das descobertas quanto o impacto do trabalho publicado. Esta análise quantitativa complementa as opiniões e os julgamentos realizados por especialistas (avaliação pelos pares, fornecendo instrumentos úteis e objetivos para avaliar os resultados da atividade científica.

  11. Evaluation of the potential for carbonaceous dust explosibility in the decommissioning of the Windscale piles

    International Nuclear Information System (INIS)

    G E Andrews; H Phylaktou; M T Cross; W Ingamells; A J Wickham

    2005-01-01

    Full text of publication follows: Concerns have been expressed by nuclear regulatory bodies, and others, about the possibility of initiating an dust explosion during the decommissioning activities in graphite-moderated reactors. The graphite and carbonaceous dusts which may be present inside the reactor vessel are regarded as a potential explosion risk, particularly in the situation where cutting activities such as the flame-cutting of adjacent steel components is taking place. In the Windscale Piles, which were air-cooled, the only carbonaceous dust which should be present is that arising from nuclear-grade graphite, and high-purity graphite has historically been classified as 'non-explosible'. However, more recent work, and particularly the application of modern standards to the classification of dusts, has somewhat changed the perspective. The standard ISO test uses a chemical igniter of 10 kJ in a spherical vessel of approximately 1 m 3 , and the chemical energy added is sufficient to result in a weak explosion in nuclear graphite when the dust concentration and particle size range are favourable. It is more than ever desirable therefore to understand in more details the characteristics of graphite dust likely to be encountered in the Windscale Piles, and in particular the effects of possible impurities and potential catalysts which might be present particularly in Pile 1 which was the scene of the core fire in 1957. In addition, it was considered prudent to investigate the propagation of pressure waves and the possibility of secondary explosions using the 'connected-enclosure' facilities at The University of Leeds which can be configured to represent approximately the relative volumes of parts of the Windscale Piles gas circuits. This work utilised Pile Grade 'A' graphite characteristic of Calder Hall reactors, the nearest currently available equivalent to that used in the Piles. The work has revealed an unexpected influence of particle size, with only the

  12. Evaluation of the potential for carbonaceous dust explosibility in the decommissioning of the Windscale piles

    International Nuclear Information System (INIS)

    Andrews, G.E.; Phylaktou, H.; Cross, M.T.; Ingamells, W.

    2005-01-01

    Full text of publication follows: Concerns have been expressed by nuclear regulatory bodies, and others, about the possibility of initiating an dust explosion during the decommissioning activities in graphite-moderated reactors. The graphite and carbonaceous dusts which may be present inside the reactor vessel are regarded as a potential explosion risk, particularly in the situation where cutting activities such as the flame-cutting of adjacent steel components is taking place. In the Windscale Piles, which were air-cooled, the only carbonaceous dust which should be present is that arising from nuclear-grade graphite, and high-purity graphite has historically been classified as 'non-explosible' [1]. However, more recent work, and particularly the application of modern standards to the classification of dusts, has somewhat changed the perspective. The standard ISO test [2] uses a chemical igniter of 10 kJ in a spherical vessel of approximately 1 m 3 , and the chemical energy, added is sufficient to result in a weak explosion in nuclear graphite when the dust concentration and particle size range are favourable. It is more than ever desirable therefore to understand in more details the characteristics of graphite dust likely to be encountered in the Windscale Piles, and in particular the effects of possible impurities and potential catalysts which might be present particularly in Pile 1 which was the scene of the core fire in 1957 [3]. In addition, it was considered prudent to investigate the propagation of pressure waves and the possibility of secondary explosions using the 'connected-enclosure' facilities at The University of Leeds which can be configured to represent approximately the relative volumes of parts o the Windscale Piles gas circuits. This work utilised Pile Grade 'A' graphite characteristic of Calder Hall reactors, the nearest currently available equivalent to that used in the Piles. The work has revealed an unexpected influence of particle size, with

  13. Isolating Weakly and Strongly-Absorbing Classes of Carbonaceous Aerosol: Optical Properties, Abundance and Lifecycle

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Tami C. [Univ. of Illinois, Urbana-Champaign, IL (United States); Rood, Mark J. [Univ. of Illinois, Urbana-Champaign, IL (United States); Riemer, Nicole [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2013-09-15

    The goal of this project was to evaluate climate-relevant properties of carbonaceous particles and the transformations of those particles in the atmosphere, with the purpose of developing lumped classes of carbonaceous particles suitable for use in large-scale models. These climate-relevant properties included light absorption and hygroscopicity. Hygroscopicity is a measure of water affinity, which governs particle growth at humid conditions and absorption and scattering under those conditions. It also controls particles’ activation into cloud droplets, which in turn affects cloud albedo and particle removal. This project used laboratory measurements of fresh and aged carbonaceous aerosol, and predictions of properties using a particle-resolved model, to identify sensitivities. The focus in this project was on aerosol from biomass pyrolysis, abbreviated BrC (“brown carbon”). We measured absorption by aerosol from biomass pyrolysis from two sources with very different composition: wood and corn stalk. For both sources, the greatest light absorption occurred at the highest generation temperature, and this maximum absorption was very similar to that of wood-generated aerosol. We suggest that pyrolysis products can be considered surrogates for a wide range of biomass aerosol. We captured aerosol emitted from biomass pyrolysis on filters and exposed it to ultraviolet radiation, to the atmospheric trace gases ozone, ammonia (NH3) and nitrogen oxide; and to aqueous saturated salt solutions of ammonium sulfate, ammonium nitrate, sodium chloride and sodium sulfate. Absorption increased, but by only small amounts for all of these treatments, with one exception: after aging with ammonia, absorption increased by almost a factor of four. Absorption increased more at visible wavelengths. We confirmed that a significant change occurred in the aerosol phase, by measuring absorption by suspended particles after aging with NH3 and finding doubled aerosol

  14. A Biblioteconomia e a Ciência da Informação na taxionomia das ciências de Charles Sanders Peirce

    Directory of Open Access Journals (Sweden)

    Carlos Cândido de Almeida

    2005-07-01

    Full Text Available Mostra a taxionomia das ciências desenvolvida por Charles Sanders Peirce (1839-1914 que divide as ciências em três ramos: ciências teóricas, ciências da revisão e ciências aplicadas. Detalha principalmente as ciências teóricas: a Matemática, a Filosofia e a Idioscopia. Discute também o conceito de Biblioteconomia e de Ciência da Informação e que segundo as definições e características, encontradas na literatura consultada, estão na condição de ciências aplicadas, direcionadas a problemas práticos da sociedade, ou seja, o problema de controle e disseminação da informação.

  15. Carbonaceous spheres—an unusual template for solid metal oxide mesoscale spheres: Application to ZnO spheres

    International Nuclear Information System (INIS)

    Patrinoiu, Greta; Calderón-Moreno, Jose Maria; Culita, Daniela C.; Birjega, Ruxandra; Ene, Ramona; Carp, Oana

    2013-01-01

    A green template route for the synthesis of mesoscale solid ZnO spheres was ascertained. The protocol involves a double coating of the carbonaceous spheres with successive layers of zinc-containing species by alternating a non-ultrasound and ultrasound-assisted deposition, followed by calcination treatments. The composites were characterized by FTIR spectroscopy, thermal analysis, scanning electron microscopy while the obtained ZnO spheres by X-ray diffraction, Raman spectroscopy, scanning and transmission electron microscopy, N 2 adsorption–desorption isotherms and photoluminescence investigations. A growth mechanism of the solid spheres is advanced based on these results. While the spheres' diameters and the mean size values of ZnO are independent on deposition order, the surface area and the external porosity are fairly dependent. The photoluminescence measurements showed interesting emission features, with emission bands in the violet to orange region. The spheres present high photocatalytical activity towards the degradation of phenol under UV irradiation, the main reaction being its mineralization. - Graphical abstract: A novel and eco-friendly methodology for the synthesis of mesoscale solid ZnO spheres was developed. The protocol involves a double coating of the starch-derived carbonaceous spheres with successive layers of zinc-containing species by alternating a non-ultrasound and ultrasound-assisted deposition, followed by calcination treatments. - Highlights: • ZnO solid spheres are obtained via a template route using carbonaceous spheres. • Two-step coatings of interchangeable order are used as deposition procedure. • The coating procedure influences the porosity and surface area. • ZnO spheres exhibited interesting visible photoluminescence properties. • Solid spheres showed photocatalytical activity in degradation of phenol

  16. The use of halogen carriers and buffers in the spectrographic determination of boron in carbonaceous materials and their combustion products

    International Nuclear Information System (INIS)

    Rucandio, M. I.; Martin, M.; Roca, M.

    1992-01-01

    For the determination of boron in carbonaceous materials (high purity graphite, coals and their processed products, such as ashes and slags from thermoelectric power plants) by atomic emission spectroscopy with direct current are excitation and photographic recording, the behaviour of the analyte in the presence of halide compounds or spectrochemical buffers has been studied. Among the halides, cupric fluoride at a low concentration (2%) becomes very suitable for the graphite analysis, and at a higher concentration (25 %) for coals, being necessary in this case to carry out a dilution of samples with graphite. Strontium carbonate as a spectrochemical buffer allows to analyse satisfactorily coals and their combustion products. (Author) 13 refs

  17. The use of halogen carriers and buffers in the spectrographic determination of boron in carbonaceous materials and their combustion products

    International Nuclear Information System (INIS)

    Rucandio, M.I.; Martin, M.; Roca, M.

    1992-01-01

    For the determination of boron in carbonaceous materials (high purity graphite, coals and their processed products, such as ashes and slags from thermoelectric power plants) by atomic emission spectroscopy with direct current arc excitation and photographic recording, the behaviour of the analyte in the presence of halide compounds or spectrochemical buffers has been studied. Among the halides, cupric fluoride at a low concentration (2%) becomes very suitable for the graphite analysis, and at a higher concentration (25%) for coals being necessary in this case to carry out a dilution of samples with graphite. Strontium carbonate as a spectrochemical buffer allows to analyse satisfactorily coals and their combustion products. (author)

  18. Variability of carbonaceous aerosols in remote, rural, urban and industrial environments in Spain: implications for air quality policy

    Science.gov (United States)

    Querol, X.; Alastuey, A.; Viana, M.; Moreno, T.; Reche, C.; Minguillón, M. C.; Ripoll, A.; Pandolfi, M.; Amato, F.; Karanasiou, A.; Pérez, N.; Pey, J.; Cusack, M.; Vázquez, R.; Plana, F.; Dall'Osto, M.; de la Rosa, J.; Sánchez de la Campa, A.; Fernández-Camacho, R.; Rodríguez, S.; Pio, C.; Alados-Arboledas, L.; Titos, G.; Artíñano, B.; Salvador, P.; García Dos Santos, S.; Fernández Patier, R.

    2013-07-01

    We interpret here the variability of levels of carbonaceous aerosols based on a 12 yr database from 78 monitoring stations across Spain specially compiled for this article. Data did not evidence any spatial trends of carbonaceous aerosols across the country. Conversely, results show marked differences in average concentrations from the cleanest, most remote sites (around 1 μg m-3 of non-mineral carbon (nmC), mostly made of organic carbon (OC) with very little elemental carbon (EC), around 0.1 μg m-3; OC / EC = 12-15), to the highly polluted major cities (8-10 μg m-3 of nmC; 3-4 μg m-3 of EC; 4-5 μg m-3 of OC; OC / EC = 1-2). Thus, urban (and very specific industrial) pollution was found to markedly increase levels of carbonaceous aerosols in Spain, with much lower impact of biomass burning and of biogenic emissions. Correlations between yearly averaged OC / EC and EC concentrations adjust very well to a potential equation (OC = 3.37 EC0.326, R2 = 0.8). A similar equation is obtained when including average concentrations obtained at other European sites (OC = 3.60EC0.491, R2 = 0.7). A clear seasonal variability in OC and EC concentrations was detected. Both OC and EC concentrations were higher during winter at the traffic and urban sites, but OC increased during the warmer months at the rural sites. Hourly equivalent black carbon (EBC) concentrations at urban sites accurately depict road traffic contributions, varying with distance from road, traffic volume and density, mixing-layer height and wind speed. Weekday urban rush-hour EBC peaks are mimicked by concentrations of primary gaseous emissions from road traffic, whereas a single midday peak is characteristic of remote and rural sites. Decreasing annual trends for carbonaceous aerosols were observed between 1999 and 2011 at a large number of stations, probably reflecting the impact of the EURO4 and EURO5 standards in reducing the diesel PM emissions. This has resulted in some cases in an increasing trend for

  19. Uranium, yttrium, and rare earth elements accumulation during the Cretaceous anoxic events in carbonaceous rocks in the Pacific Ocean

    Science.gov (United States)

    Savelyeva, Olga; Philosofova, Tatyana; Bergal-Kuvikas, Olga; Savelyeva, Svetlana

    2017-04-01

    We have studied the carbonate-siliceous section of paleooceanic Albian-Cenomanian deposits on the Kamchatsky Mys peninsula (Eastern Kamchatka, Russia) [1].The section is represented by a rhythmic alternation of planktonic limestones and jaspers, accumulated in the open ocean environment. The rhythmicity can be attributed to climate variations that reflect a fluctuation of astronomical parameters (Milankovitch cycles) [2, 3].The section contains two beds enriched in organic carbon, corresponding to the two oceanic anoxic events - MCE and OAE2 [3]. The maximum content of organic matter in those beds reaches 68%. Our geochemical studies revealed an enrichment of the carbonaceous rocks in some major and trace elements including PGE, in comparison with the surrounding limestone and jasper [4].The accumulation of the ore elements in carbonaceous beds is caused by euxinic conditions during sedimentation.The content of uranium, yttrium, and rare earth elements in carbonaceous rocks is up to 60, 142 and 312 ppm respectively. Phosphate grains (bone detritus) with microinclusions of yttrium and uranium minerals were revealed in the carbonaceous rocks using the scanning electron microscope. These data prove the hypothesis of the sorbtion of U and Y by phosphate detritus from seawater. Microprobe analysis also showed an increased content of Cu, Zn, V in some pyrite framboids, which indicates that these elements are fixed in rocks by Fe-sulphide phase or organic matter under euxinic conditions. Our research may bring us closer to understanding the mechanism of syngenetic accumulation of metals in the black shales. This work was supported by the RFBR (No. 16-05-00546). [1] Palechek, T.N., Savelyev, D.P., Savelyeva, O.L. (2010) Stratigraphy and Geological Correlation 18, (1) 63-82. [2] Savelyeva, O.L. (2010). Vestnik Kraunts. Nauki o zemle 1 (15), 45-55 (in Russian). [3] Savelyev, D.P., Savelyeva, O.L., Palechek, T.N., Pokrovsky, B.G. (2012) Geophysical Research Abstracts, 14, EGU

  20. Variability of carbonaceous aerosols in remote, rural, urban and industrial environments in Spain: implications for air quality policy

    Directory of Open Access Journals (Sweden)

    X. Querol

    2013-07-01

    Full Text Available We interpret here the variability of levels of carbonaceous aerosols based on a 12 yr database from 78 monitoring stations across Spain specially compiled for this article. Data did not evidence any spatial trends of carbonaceous aerosols across the country. Conversely, results show marked differences in average concentrations from the cleanest, most remote sites (around 1 μg m−3 of non-mineral carbon (nmC, mostly made of organic carbon (OC with very little elemental carbon (EC, around 0.1 μg m−3; OC / EC = 12–15, to the highly polluted major cities (8–10 μg m−3 of nmC; 3–4 μg m−3 of EC; 4–5 μg m−3 of OC; OC / EC = 1–2. Thus, urban (and very specific industrial pollution was found to markedly increase levels of carbonaceous aerosols in Spain, with much lower impact of biomass burning and of biogenic emissions. Correlations between yearly averaged OC / EC and EC concentrations adjust very well to a potential equation (OC = 3.37 EC0.326, R2 = 0.8. A similar equation is obtained when including average concentrations obtained at other European sites (OC = 3.60EC0.491, R2 = 0.7. A clear seasonal variability in OC and EC concentrations was detected. Both OC and EC concentrations were higher during winter at the traffic and urban sites, but OC increased during the warmer months at the rural sites. Hourly equivalent black carbon (EBC concentrations at urban sites accurately depict road traffic contributions, varying with distance from road, traffic volume and density, mixing-layer height and wind speed. Weekday urban rush-hour EBC peaks are mimicked by concentrations of primary gaseous emissions from road traffic, whereas a single midday peak is characteristic of remote and rural sites. Decreasing annual trends for carbonaceous aerosols were observed between 1999 and 2011 at a large number of stations, probably reflecting the impact of the EURO4 and EURO5 standards in reducing the diesel PM emissions. This has resulted in some

  1. Catalytic production of Jatropha biodiesel and hydrogen with magnetic carbonaceous acid and base synthesized from Jatropha hulls

    International Nuclear Information System (INIS)

    Zhang, Fan; Tian, Xiao-Fei; Fang, Zhen; Shah, Mazloom; Wang, Yi-Tong; Jiang, Wen; Yao, Min

    2017-01-01

    Graphical abstract: Jatropha seeds were extracted oil for biodiesel production and the hulls were carbonized to load active sites as magnetic carbonaceous solid acid and base catalysts. Crude Jatropha oil was esterified to decrease its acid value to 1.3 from 17.2 mg KOH/g by the solid acid, and subsequently transesterified to biodiesel (96.7% yield) catalyzed by the solid base. After 3 cycles and magnetically separated, the deactivated base was catalyzed the hydrothermal gasification of biodiesel by-product (crude glycerol) with gasification rate of 81% and 82% H 2 purity. - Highlights: • High acid value (AV) crude oil was extracted from Jatropha seeds with waste hulls produced. • Carbonizing the hulls and loading active sites produced magnetic carbonaceous acid and base. • The acid reduced AV of crude oil to 1.3 from 17.2 mg KOH/g and separated for 3 cycles. • The base achieved 97.5% biodiesel yield and magnetically separated for recycles. • After 3 cycles, the deactivated base catalyzed the hydrothermal gasification of glycerol. - Abstract: Magnetic carbonaceous solid acid (C-SO 3 H@Fe/JHC) and base (Na 2 SiO 3 @Ni/JRC) catalysts were synthesized by loading active groups on the carbonaceous supporters derived from Jatropha-hull hydrolysate and hydrolysis residue. Characterization of their morphology, magnetic saturation, functional groups and total acid/base contents were performed by various techniques. Additional acidic functional groups that formed with Jatropha-hull hydrolysate contributed to the high acidity of C-SO 3 H@Fe/JHC catalyst for the pretreatment (esterification) of crude Jatropha oil with high acid values (AV). The AV of esterified Jatropha oil dropped down from 17.2 to 1.3 mg KOH/g, achieving a high biodiesel yield of 96.7% after subsequent transesterification reaction with Na 2 SiO 3 @Ni/JRC base that was cycled at least 3 times with little loss of catalysis activity. Both solid acid and base catalysts were easily recovered by magnetic

  2. Um olhar sobre as concepções de ciência e ensino de ciências de alunos-concluintes de química

    OpenAIRE

    RIBEIRO, Evandro Luiz da Luz

    2005-01-01

    O objetivo deste trabalho foi o de investigar as concepções de Ciência e de Ensino de Ciências de alunos concluintes de Licenciatura Plena em Ciências com habilitação em Química, turma de concluintes do segundo semestre de 2004 na UFPA, contando com uma total de 12 sujeitos de pesquisa. Para a identificação das concepções de Ciência e de Ensino de Ciências, foi elaborado um questionário, previamente testado com 15 alunos concluintes do Curso de Licenciatura Plena em Biologia, objetivando a va...

  3. Progression towards optimization of viscosity of highly concentrated carbonaceous solid-water slurries by incorporating and modifying surface chemistry parameters with and without additives

    Science.gov (United States)

    Mukherjee, Amrita

    Carbonaceous solid-water slurries (CSWS) are concentrated suspensions of coal, petcoke bitumen, pitch etc. in water which are used as feedstock for gasifiers. The high solid loading (60-75 wt.%) in the slurry increases CSWS viscosity. For easier handling and pumping of these highly loaded mixtures, low viscosities are desirable. Depending on the nature of the carbonaceous solid, solids loading in the slurry and the particle size distribution, viscosity of a slurry can vary significantly. Ability to accurately predict the viscosity of a slurry will provide a better control over the design of slurry transport system and for viscosity optimization. The existing viscosity prediction models were originally developed for hard-sphere suspensions and therefore do not take into account surface chemistry. As a result, the viscosity predictions using these models for CSWS are not very accurate. Additives are commonly added to decrease viscosity of the CSWS by altering the surface chemistry. Since additives are specific to CSWS, selection of appropriate additives is crucial. The goal of this research was to aid in optimization of CSWS viscosity through improved prediction and selection of appropriate additive. To incorporate effect of surface chemistry in the models predicting suspension viscosity, the effect of the different interfacial interactions caused by different surface chemistries has to be accounted for. Slurries of five carbonaceous solids with varying O/C ratio (to represent different surface chemistry parameters) were used for the study. To determine the interparticle interactions of the carbonaceous solids in water, interfacial energies were calculated on the basis of surface chemistries, characterized by contact angles and zeta potential measurements. The carbonaceous solid particles in the slurries were assumed to be spherical. Polar interaction energy (hydrophobic/hydrophilic interaction energy), which was observed to be 5-6 orders of magnitude higher than the

  4. Crystallography of refractory metal nuggets in carbonaceous chondrites: A transmission Kikuchi diffraction approach

    Science.gov (United States)

    Daly, Luke; Bland, Phil A.; Dyl, Kathryn A.; Forman, Lucy V.; Saxey, David W.; Reddy, Steven M.; Fougerouse, Denis; Rickard, William D. A.; Trimby, Patrick W.; Moody, Steve; Yang, Limei; Liu, Hongwei; Ringer, Simon P.; Saunders, Martin; Piazolo, Sandra

    2017-11-01

    Transmission Kikuchi diffraction (TKD) is a relatively new technique that is currently being developed for geological sample analysis. This technique utilises the transmission capabilities of a scanning electron microscope (SEM) to rapidly and accurately map the crystallographic and geochemical features of an electron transparent sample. TKD uses a similar methodology to traditional electron backscatter diffraction (EBSD), but is capable of achieving a much higher spatial resolution (5-10 nm) (Trimby, 2012; Trimby et al., 2014). Here we apply TKD to refractory metal nuggets (RMNs) which are micrometre to sub-micrometre metal alloys composed of highly siderophile elements (HSEs) found in primitive carbonaceous chondrite meteorites. TKD allows us to analyse RMNs in situ, enabling the characterisation of nanometre-scale variations in chemistry and crystallography, whilst preserving their spatial and crystallographic context. This provides a complete representation of each RMN, permitting detailed interpretation of their formation history. We present TKD analysis of five transmission electron microscopy (TEM) lamellae containing RMNs coupled with EBSD and TEM analyses. These analyses revealed textures and relationships not previously observed in RMNs. These textures indicate some RMNs experienced annealing, forming twins. Some RMNs also acted as nucleation centres, and formed immiscible metal-silicate fluids. In fact, each RMN analysed in this study had different crystallographic textures. These RMNs also had heterogeneous compositions, even between RMNs contained within the same inclusion, host phase and even separated by only a few nanometres. Some RMNs are also affected by secondary processes at low temperature causing exsolution of molybdenite. However, most RMNs had crystallographic textures indicating that the RMN formed prior to their host inclusion. TKD analyses reveal most RMNs have been affected by processing in the protoplanetary disk. Despite this

  5. Ultraviolet reflectance spectroscopy measurements of carbonaceous meteorites and planetary analog materials

    Science.gov (United States)

    Hibbitts, Charles A.; Stockstill-Cahill, Karen; Takir, Driss

    2017-10-01

    The compositions of airless solar system objects tell us about the origin and evolutionary processes that are responsible for the current state of our solar system and that shape our environment. Spectral reflectance measurements in the ultraviolet are being used more frequently for providing compositional information of airless solid surfaces. Most minerals absorb in the UV making studying surface composition both informative but also challenging [e.g. 1]. The UV region is sensitive to atomic and molecular electronic absorptions such as the ligand-metal charge transfer band that is present in oxides and silicates and the conduction band at vacuum UV wavelengths. At the JHU-APL, bidirectional UV reflectance measurements are obtained under vacuum using a McPherson monochrometer with a PMT detector to achieve measurements over the range from ~ 140 nm to ~ 570 nm. Sample temperature can also be controlled from ~ 100K to ~ 600K, which enables the exploring the interaction of water ice and other volatiles with refractory samples. We have measured the UV spectra of many carbonaceous chondrites, including Mokoia, Vigarano, Warrenton, Orgueil, SaU290, and Essebi. In addition to being dark, some also possess on OMCT band. We have also obtained IR measurement of these meteorites to explore possible correlations between their UV and IR spectral signatures. In addition, we have also measured the UV spectra of low water content lunar analog glasses and have found a correlation between the spectral nature of the OMCT band and the abundance of iron [3]. Also, the spectral signature of mineralic and adsorbed water in the UV has been investigated. While water-ice has a known strong absorption feature near 180 nm (e.g. 4], adsorbed molecular and disassociatively adsorbed OH appear to not be optically active in this spectral region [5]. References: [1] Wagner et al. (1987) Icarus, 69, 14-28.1987; [2] Cloutis et al. (2008) Icarus, 197, 321-347; [3] Greenspon et al. (2012), 43rd LPSC

  6. Feasibility study for GCOM-C/SGLI: Retrieval algorithms for carbonaceous aerosols

    Science.gov (United States)

    Mukai, Sonoyo; Sano, Itaru; Yasumoto, Masayoshi; Fujito, Toshiyuki; Nakata, Makiko; Kokhanovsky, Alexander

    2016-04-01

    The Japan Aerospace Exploration Agency (JAXA) has been developing the new Earth observing system, GCOM (Global Change Observation Mission) project, which consists of two satellite series of GCOM-W1 and GCOM-C1. The 1st GCOM-C satellite will board the SGLI (second generation global imager) which also includes polarimetric sensor and be planed to launch in early of 2017. The SGLI has multi (19)-channels including near UV channel (380 nm) and two polarization channels at red and near-infrared wavelengths of 670 and 870 nm. EUMETSAT plans to collect polarization measurements with a POLDER follow on 3MI / EPS-SG in 2021. Then the efficient retrieval algorithms for aerosol and/or cloud based on the combination use of radiance and polarization are strongly expected. This work focuses on serious biomass burning episodes in East Asia. It is noted that the near UV measurements are available for detection of the carbonaceous aerosols. The biomass burning aerosols (BBA) generated by forest fire and/or agriculture biomass burning have influenced on the severe air pollutions. It is known that the forest fire increases due to global warming and a climate change, and has influences on them vice versa. It is well known that this negative cycle decreases the quality of global environment and human health. We intend to consider not only retrieval algorithms of remote sensing for severe air pollutions but also detection and/or distinction of aerosols and clouds, because mixture of aerosols and clouds are often occurred in the severe air pollutions. Then precise distinction of aerosols and clouds, namely aerosols in cloudy scenes and/or clouds in heavy aerosol episode, is desired. Aerosol retrieval in the hazy atmosphere has been achieved based on radiation simulation method of successive order of scattering 1,2. In this work, we use both radiance and polarization measurements observed by GLI and POLDER-2 on Japanese ADEOS-2 satellite in 2003 as a simulated data. As a result the

  7. Sources of PM2.5 carbonaceous aerosol in Riyadh, Saudi Arabia

    Science.gov (United States)

    Bian, Qijing; Alharbi, Badr; Shareef, Mohammed M.; Husain, Tahir; Pasha, Mohammad J.; Atwood, Samuel A.; Kreidenweis, Sonia M.

    2018-03-01

    Knowledge of the sources of carbonaceous aerosol affecting air quality in Riyadh, Saudi Arabia, is limited but needed for the development of pollution control strategies. We conducted sampling of PM2.5 from April to September 2012 at various sites in the city and used a thermo-optical semi-continuous method to quantify the organic carbon (OC) and elemental carbon (EC) concentrations. The average OC and EC concentrations were 4.7 ± 4.4 and 2.1 ± 2.5 µg m-3, respectively, during this period. Both OC and EC concentrations had strong diurnal variations, with peaks at 06:00-08:00 LT and 20:00-22:00 LT, attributed to the combined effect of increased vehicle emissions during rush hour and the shallow boundary layer in the early morning and at night. This finding suggested a significant influence of local vehicular emissions on OC and EC. The OC / EC ratio in primary emissions was estimated to be 1.01, close to documented values for diesel emissions. Estimated primary organic carbon (POC) and secondary organic carbon (SOC) concentrations were comparable, with average concentrations of 2.0 ± 2.4 and 2.8 ± 3.4 µg m-3, respectively.We also collected 24 h samples of PM10 onto quartz microfiber filters and analyzed these for an array of metals by inductively coupled plasma atomic emission spectroscopy (ICP-AES). Total OC was correlated with Ca (R2 of 0.63), suggesting that OC precursors and Ca may have similar sources, and the possibility that they underwent similar atmospheric processing. In addition to a ubiquitous dust source, Ca is emitted during desalting processes in the numerous refineries in the region and from cement kilns, suggesting these sources may also contribute to observed OC concentrations in Riyadh. Concentration weighted trajectory (CWT) analysis showed that high OC and EC concentrations were associated with air masses arriving from the Persian Gulf and the region around Baghdad, locations with high densities of oil fields and refineries as well as a

  8. Adsorption of mercury by carbonaceous adsorbents prepared from rubber of tyre wastes.

    Science.gov (United States)

    Manchón-Vizuete, E; Macías-García, A; Nadal Gisbert, A; Fernández-González, C; Gómez-Serrano, V

    2005-03-17

    Rubber from tyre wastes has been used to prepare carbonaceous adsorbents and the products obtained have been tested as adsorbents for mercury in aqueous solution. The adsorbents have been prepared by applying thermal, chemical and combined (thermal and chemical or vice versa) treatments. Tyre rubber has been: heated at 400 or 900 degrees C for 2 h in N2, chemically-treated with H2SO4, HNO3 or H2SO4/HNO3 solution for 24 h, and in two successive steps first heated at 400 degrees C for 2h in N2 and then treated with a H2SO4/HNO3 solution for 24 h, or vice versa. Resultant products have been characterised in terms of elementary composition and textural properties. The adsorption of mercury has been studied from kinetic and equilibrium standpoints. The treatments effected to tyre rubber decrease the carbon content and the hydrogen content. The oxygen content and the nitrogen content increase for the chemically-treated products. The heat treatment of tyre rubber results in a larger development of surface area, microporosity, and mesoporosity than the chemical treatments. These treatments, however, produce a great creation of macropores. In comparison to the starting rubber, the adsorption process of mercury is faster when the material is heated or treated with the H2SO4, HNO3 or 1:3 H2SO4/HNO3 solution. These adsorbents are either a non-porous solid or possess a high mesopore volume or a wide pore size distribution in the macropore range. The adsorption capacity is larger for products prepared by heat, chemical and combined treatments of the rubber. A common textural characteristic of these adsorbents is their better developed microporosity. The ability to adsorb mercury is higher for the heated products than for the chemically-treated ones. The maximum adsorption of mercury is 211 mg g(-1). The constant Kf of the Freundlich equation is as high as 108.9 mg g(-1).

  9. Oxygen, Magnesium, and Aluminum Isotopes in the Ivuna CAI: Re-Examining High-Temperature Fractionations in CI Chondrites

    Science.gov (United States)

    Frank, D. R.; Huss, G. R.; Nagashima, K.; Zolensky, M. E.; Le, L.

    2017-01-01

    CI chondrites are thought to approximate the bulk solar system composition since they closely match the composition of the solar photosphere. Thus, chemical differences between a planetary object and the CI composition are interpreted to result from fractionations of a CI starting composition. This interpretation is often made despite the secondary mineralogy of CI chondrites, which resulted from low-T aqueous alteration on the parent asteroid(s). Prevalent alteration and the relatively large uncertainties in the photospheric abundances (approx. +/-5-10%) permit chemical fractionation of CI chondrites from the bulk solar system, if primary chondrules and/or CAIs have been altered beyond recognition. Isolated olivine and pyroxene grains that range from approx. 5 microns to several hundred microns have been reported in CI chondrites, and acid residues of Orgueil were found to contain refractory oxides with oxygen isotopic compositions matching CAIs. However, the only CAI found to be unambiguously preserved in a CI chondrite was identified in Ivuna. The Ivuna CAI's primary mineralogy, small size (approx.170 microns), and fine-grained igneous texture classify it as a compact type A. Aqueous alteration infiltrated large portions of the CAI, but other regions remain pristine. The major primary phases are melilite (Ak 14-36 ), grossmanite (up to 20.8 wt.% TiO 2 ), and spinel. Both melilite and grossmanite have igneous textures and zoning patterns. An accretionary rim consists primarily of olivine (Fa 2-17 ) and low-Ca pyroxene (Fs 2-10 ), which could be either surviving CI2 material or a third lithology.

  10. Direct Simple Shear Test Data Analysis using Jupyter Notebooks on DesignSafe-CI

    Science.gov (United States)

    Eslami, M.; Esteva, M.; Brandenberg, S. J.

    2017-12-01

    Due to the large number of files and their complex structure, managing data generated during natural hazards experiments requires scalable and specialized tools. DesignSafe-CI (https://www.designsafe-ci.org/) is a web-based research platform that provides computational tools to analyze, curate, and publish critical data for natural hazards research making it understandable and reusable. We present a use case from a series of Direct Simple Shear (DSS) experiments in which we used DS-CI to post-process, visualize, publish, and enable further analysis of the data. Current practice in geotechnical design against earthquakes relies on the soil's plasticity index (PI) to assess liquefaction susceptibility, and cyclic softening triggering procedures, although, quite divergent recommendations on recommended levels of plasticity can be found in the literature for these purposes. A series of cyclic and monotonic direct simple shear experiments was conducted on three low-plasticity fine-grained mixtures at the same plasticity index to examine the effectiveness of the PI in characterization of these types of materials. Results revealed that plasticity index is an insufficient indicator of the cyclic behavior of low-plasticity fine-grained soils, and corrections for pore fluid chemistry and clay minerology may be necessary for future liquefaction susceptibility and cyclic softening assessment procedures. Each monotonic, or cyclic experiment contains two stages; consolidation and shear, which include time series of load, displacement, and corresponding stresses and strains, as well as equivalent excess pore-water pressure. Using the DS-CI curation pipeline we categorized the data to display and describe the experiment's structure and files corresponding to each stage of the experiments. Two separate notebooks in Python 3 were created using the Jupyter application available in DS-CI. A data plotter aids visualizing the experimental data in relation to the sensor from which it was

  11. Solar radiation synthesis of functional carbonaceous materials using Al2O3/TiO2-Cu-HA doped catalyst

    Science.gov (United States)

    Stanciu, Elena Manuela; Pascu, Alexandru; Roată, Ionut Claudiu; Croitoru, Cătălin; Tierean, Mircea; Rosca, Julia Mirza; Hulka, Iosif

    2018-04-01

    Single carbon nanotubes were synthesized through a physical vapor deposition method, using concentrated solar radiation as means of vaporization and promoting the formation of carbonaceous plasma plume. A novel catalyst, containing multiple hybrid ceramic/metal phases has been obtained through flame spraying. In conjunction with this catalyst, good quality nanomaterials, such as long single-walled nanotubes and nanoparticles have been obtained and characterized by both morphological (SEM, TEM) as well as structural means on analysis (XRD, FTIR). A mild oxidation of the carbonaceous phase has been reported, which could prove useful in applications in conjunction with metals or hydrophilic polymers as potential matrices for nanocomposites obtaining.

  12. Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites

    Science.gov (United States)

    Cooper, George; Reed, Chris; Nguyen, Dang; Carter, Malika; Wang, Yi

    2011-01-01

    Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a “one pot” suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using 13C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems. PMID:21825143

  13. Thermal and electrochemical durability of carbonaceous composites used as a bipolar plate of proton exchange membrane fuel cell

    Science.gov (United States)

    Kinumoto, Taro; Nagano, Keita; Tsumura, Tomoki; Toyoda, Masahiro

    Thermal and electrochemical durability of carbonaceous composite plates, which are made from graphite powders and a resin for use as bipolar plates of PEMFC (proton exchange membrane fuel cell), were investigated. The thermal durability was investigated by TG (thermal gravimetry) coupled with DTA (differential thermal analysis) technique under air up to 600 °C. A weight loss was significant over 300 °C, but the hydrophobicity was decreased after heated at 80 °C for 192 h. The electrochemical durability was investigated in 10 μmol dm -3 of hydrochloric acid solution under nitrogen or oxygen atmosphere by means of potential holding test from 0.8 to 1.5 V against RHE (reversible hydrogen electrode) at 80 °C. During the potential holding tests, CO 2 production due to the corrosion was quantified by a GC (gas-chromatography) and the production was detectable above 1.3 V irrespective with atmosphere; on the other hand, it was clarified from the contact angle measurements that the hydrophobicity was changed below 1.3 V. The results of this study showed that the carbonaceous composite plates were electrochemically degraded under PEMFC condition and were seriously degraded in URFC (unitized regenerative fuel cell) condition.

  14. TOWARD THE FORMATION OF CARBONACEOUS REFRACTORY MATTER IN HIGH TEMPERATURE HYDROCARBON-RICH ATMOSPHERES OF EXOPLANETS UPON MICROMETEOROID IMPACT

    Energy Technology Data Exchange (ETDEWEB)

    Dangi, Beni B.; Kim, Yong S.; Krasnokutski, Serge A.; Kaiser, Ralf I. [Department of Chemistry, University of Hawai’i at Manoa, Honolulu, HI 96822 (United States); Bauschlicher Jr, Charles W. [Entry Systems and Technology Division, NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2015-05-20

    We report on laboratory simulation experiments mimicking the chemical processing of model atmospheres of exoplanets containing C3 and C4 hydrocarbons at moderate temperatures of 400 K upon interaction of catalytic surfaces of micrometeoroids. By utilizing an ultrasonic levitator device and heating singly levitated particles under simulated microgravity conditions, Raman spectroscopy is utilized as a non-invasive tool to probe on line and in situ the conversion of C3 and C4 hydrocarbons to refractory carbonaceous matter on the surfaces of levitated particles. Secondary Ion Mass Spectrometry and electron microscopic imaging were also conducted to gain further insight into the elementary composition and structures of the refractories formed. Our results provide compelling evidence that in the presence of a catalytic surface, which can be supplied in the form of micrometeoroids and atmospheric dust particles, hydrocarbon gases present in the atmospheres of exoplanets can be converted to refractory, carbon-rich carbonaceous matter of mainly graphitic structure with a carbon content of at least 90% at elevated temperatures. This finding might explain the low methane to carbon monoxide (CH{sub 4}–CO) ratio in the hot Neptune GJ 436b, where the abundant methane photochemically converts to higher order hydrocarbons and ultimately to refractory graphite-like carbon in the presence of a silicon surface.

  15. Composition of carbonaceous smoke particles from prescribed burning of a Canadian boreal forest: 1. Organic aerosol characterization by gas chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Mazurek, M.A.; Laterza, C.; Newman, L.; Daum, P. [Brookhaven National Lab., Upton, NY (United States); Cofer, W.R. III; Levine, J.S. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center; Winstead, E.L. [Science Applications International Corporation, Hampton, VA (United States)

    1995-06-01

    In this study we examine the molecular organic constituents (C8 to C40 lipid compounds) collected as smoke particles from a Canadian boreal forest prescribed burn. Of special interest are (1) the molecular identity of polar organic aerosols, and (2) the amount of polar organic matter relative to the total mass of aerosol particulate carbon. Organic extracts of smoke aerosol particles show complex distributions of the lipid compounds when analyzed by capillary gas chromatography/mass spectrometry. The molecular constituents present as smoke aerosol are grouped into non-polar (hydrocarbons) and polar {minus}2 oxygen atoms) subtractions. The dominant chemical species found in the boreal forest smoke aerosol are unaltered resin compounds (C20 terpenes) which are abundant in unburned conifer wood, plus thermally altered wood lignins and other polar aromatic hydrocarbons. Our results show that smoke aerosols contain molecular tracers which are related to the biofuel consumed. These smoke tracers can be related structurally back to the consumed softwood and hardwood vegetation. In addition, combustion of boreal forest materials produces smoke aerosol particles that are both oxygen-rich and chemically complex, yielding a carbonaceous aerosol matrix that is enriched in polar substances. As a consequence, emissions of carbonaceous smoke particles from large-scale combustion of boreal forest land may have a disproportionate effect on regional atmospheric chemistry and on cloud microphysical processes.

  16. Non-destructive elemental analysis of a carbonaceous chondrite with direct current Muon beam at MuSIC.

    Science.gov (United States)

    Terada, K; Sato, A; Ninomiya, K; Kawashima, Y; Shimomura, K; Yoshida, G; Kawai, Y; Osawa, T; Tachibana, S

    2017-11-13

    Electron- or X-ray-induced characteristic X-ray analysis has been widely used to determine chemical compositions of materials in vast research fields. In recent years, analysis of characteristic X-rays from muonic atoms, in which a muon is captured, has attracted attention because both a muon beam and a muon-induced characteristic X-ray have high transmission abilities. Here we report the first non-destructive elemental analysis of a carbonaceous chondrite using one of the world-leading intense direct current muon beam source (MuSIC; MUon Science Innovative Channel). We successfully detected characteristic muonic X-rays of Mg, Si, Fe, O, S and C from Jbilet Winselwan CM chondrite, of which carbon content is about 2 wt%, and the obtained elemental abundance pattern was consistent with that of CM chondrites. Because of its high sensitivity to carbon, non-destructive elemental analysis with a muon beam can be a novel powerful tool to characterize future retuned samples from carbonaceous asteroids.

  17. Compact Combustor Integrated (CI) with Compressor and Turbine for Perspective Turbojet Engine

    Science.gov (United States)

    Strokin, V. N.; Volkov, S. A.; Ljashenko, V. P.; Popov, V. I.; Startzev, A. N.; Nigmatullin, R. Z.; Shilova, T. V.; Belikov, U. V.

    2017-11-01

    For several years, CIAM has conducted comprehensive work on the development the combustor integrated (CI) with air swirling. This project involved an integrated development of three components: diffuser, combustion chamber and nozzle guide vanes of turbine to reduce their length and, respectively, the length of the engine and obtain high performance elements with low emissions of harmful substances. The new frontal device was proposed for CI combustor. The design optimization of this type combustor was conducted in the compartments and in a full-size combustion chamber. It was shown the possibility of obtaining high combustion efficiency and low NOx emissions at a short length on cruise condition. By a simplified model of the frontal device it was shown experimentally that the proposed device provided a lighting-up and flame spreading in a wide range of equivalence ratio ER (ER > 0.014) at idling. It was shown that short vane diffuser with moderate swirling ensured high parameters of the combustion chamber. The use of residual swirling of the combustion products at the exit of combustor allows reducing the size, or the number of nozzle guide vanes of the turbine. In General, the use of the swirling of the air stream gives a possibility of total length reduction for all three elements by about 20 – 25 %.

  18. Proarrhythmia liability assessment and the comprehensive in vitro Proarrhythmia Assay (CiPA): An industry survey on current practice.

    Science.gov (United States)

    Authier, Simon; Pugsley, Michael K; Koerner, John E; Fermini, Bernard; Redfern, William S; Valentin, Jean-Pierre; Vargas, Hugo M; Leishman, Derek J; Correll, Krystle; Curtis, Michael J

    2017-07-01

    The Safety Pharmacology Society (SPS) has conducted a survey of its membership to identify industry practices related to testing considered in the Comprehensive In vitro Proarrhythmia Assay (CiPA). Survey topics included nonclinical approaches to address proarrhythmia issues, conduct of in silico studies, in vitro ion channel testing methods used, drugs used as positive controls during the conduct of cardiac ion channel studies, types of arrhythmias observed in non-clinical studies and use of the anticipated CiPA ion channel assay. In silico studies were used to evaluate effects on ventricular action potentials by only 15% of responders. In vitro assays were used mostly to assess QT prolongation (95%), cardiac Ca 2+ and Na + channel blockade (82%) and QT shortening or QRS prolongation (53%). For de-risking of candidate drugs for proarrhythmia, those assays most relevant to CiPA including cell lines stably expressing ion channels used to determine potency of drug block were most frequently used (89%) and human stem cell-derived or induced pluripotent stem cell cardiomyocytes (46%). Those in vivo assays related to general proarrhythmia derisking include ECG recording using implanted telemetry technology (88%), jacketed external telemetry (62%) and anesthetized animal models (53%). While the CiPA initiative was supported by 92% of responders, there may be some disconnect between current practice and future expectations, as explained. Proarrhythmia liability assessment in drug development presently includes study types consistent with CiPA. It is anticipated that CiPA will develop into a workable solution to the concern that proarrhythmia liability testing remains suboptimal. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Composition and sources of carbonaceous aerosols in Northern Europe during winter

    Science.gov (United States)

    Glasius, M.; Hansen, A. M. K.; Claeys, M.; Henzing, J. S.; Jedynska, A. D.; Kasper-Giebl, A.; Kistler, M.; Kristensen, K.; Martinsson, J.; Maenhaut, W.; Nøjgaard, J. K.; Spindler, G.; Stenström, K. E.; Swietlicki, E.; Szidat, S.; Simpson, D.; Yttri, K. E.

    2018-01-01

    Sources of elemental carbon (EC) and organic carbon (OC) in atmospheric aerosols (carbonaceous aerosols) were investigated by collection of weekly aerosol filter samples at six background sites in Northern Europe (Birkenes, Norway; Vavihill, Sweden; Risoe, Denmark; Cabauw and Rotterdam in The Netherlands; Melpitz, Germany) during winter 2013. Analysis of 14C and a set of molecular tracers were used to constrain the sources of EC and OC. During the four-week campaign, most sites (in particular those in Germany and The Netherlands) were affected by an episode during the first two weeks with high concentrations of aerosol, as continental air masses were transported westward. The analysis results showed a clear, increasing north to south gradient for most molecular tracers. Total carbon (TC = OC + EC) at Birkenes showed an average concentration of 0.5 ± 0.3 μg C m-3, whereas the average concentration at Melpitz was 6.0 ± 4.3 μg C m-3. One weekly mean TC concentration as high as 11 μg C m-3 was observed at Melpitz. Average levoglucosan concentrations varied by an order of magnitude from 25 ± 13 ng m-3 (Birkenes) to 249 ± 13 ng m-3 (Melpitz), while concentrations of tracers of fungal spores (arabitol and mannitol) and vegetative debris (cellulose) were very low, showing a minor influence of primary biological aerosol particles during the North European winter. The fraction of modern carbon generally varied from 0.57 (Melpitz) to 0.91 (Birkenes), showing an opposite trend compared to the molecular tracers and TC. Total concentrations of 10 biogenic and anthropogenic carboxylic acids, mainly of secondary origin, were 4-53 ng m-3, with the lowest concentrations observed at Birkenes and the highest at Melpitz. However, the highest relative concentrations of carboxylic acids (normalized to TC) were observed at the most northern sites. Levels of organosulphates and nitrooxy organosulphates varied more than two orders of magnitude, from 2 to 414 ng m-3, between

  20. Light scattering by clouds of cosmic dust analogues with carbonaceous compounds (PROGRA2 experiment)

    Science.gov (United States)

    Hadamcik, Edith; Renard, Jean-Baptiste; Levasseur-Regourd, Anny-Chantal; Lasue, Jeremie

    Carbonaceous compounds are found in numerous clouds of solid particles in the Solar System (e.g. Cometary comae, Interplanetary dust, Titan's aerosols). Fluffy aggregates of submicron sized grains and more compact particles up to some tens of micrometers were present in the particles captured by the Stardust mission in the coma of comet 81P/Wild 2 [1]. Complex organic refractories were found in the particles together with silicates [2,3], while CHON particles were detected by mass spectrometer, as previously by Vega 1 and Giotto at 1P/Halley [4,5]. Titan's aerosols are complex organics (CxNyHz) and their light scattering properties can only be interpreted if they present a fluffy aggregates structure [6]. The light scattered by the dust particles is partially linearly polarized with a polarization degree depending on the physical properties of the dust and on the geometry (phase angle) and wavelength of observations [7]. Laboratory scattering measurements with the PROGRA2 experiment [8] (in A300- CNES and ESA dedicated microgravity flights or on ground for low density particles) offer an alternative to simulate the scattering properties of real particles particularly for structures too large or too complex to be handled easily by numerical simulations. Experimental simulations have been performed on numerous samples underlying the characteristics of the polarimetric phase curves such as maximum and minimum polarization as a function of the properties of the particles (grains and particles size, structure, refractive index) [9,10]. These results were used to interpret variations in polarization in cometary comae [11,12] or in the Titan's atmosphere [13]. In this presentation we emphasize the optical properties due to the presence of organics and C-bearing materials and compare them to the optical properties of more transparent materials included or not in organics. Finally we give some examples of application to the interpretation of Solar System dust observations

  1. Seasonal variability of carbonaceous aerosols in an urban background area in Southern Italy

    Science.gov (United States)

    Cesari, D.; Merico, E.; Dinoi, A.; Marinoni, A.; Bonasoni, P.; Contini, D.

    2018-02-01

    Organic (OC) and Elemental Carbon (EC) are important components of atmospheric aerosol particles, playing a key role in climate system and potentially affecting human health. There is a lack of data reported for Southern Italy and this work aims to fill this gap, focusing the attention on the long-term trends of OC and EC concentrations in PM2.5 and PM10, and on atmospheric processes and sources influencing seasonal variability. Measurements were taken at the Environmental-Climate Observatory of Lecce (SE Italy, 40°20‧8″N-18°07‧28″E, 37 m a.s.l.), regional station of the Global Atmosphere Watch program (GAW-WMO). Daily PM10 and PM2.5 samples were collected between July 2013 and July 2016. In addition, starting in December 2014, simultaneous equivalent Black Carbon (eBC) concentrations in PM10 were measured using a Multi Angle Absorption Photometer. A subset of 722 PM samples (361 for each size fraction) was analysed by using a thermo-optical method with a Sunset Laboratory OC/EC analyser, to determine elemental and organic carbon concentrations. The average PM10 and PM2.5 concentrations were 28.8 μg/m3 and 17.5 μg/m3. The average OC and EC concentrations in PM10 were 5.4 μg/m3 and 0.8 μg/m3, in PM2.5 these were 4.7 μg/m3 and 0.6 μg/m3. Carbonaceous content was larger during cold season with respect to warm season as well as secondary organic carbon (SOC) that was evaluated using the OC/EC minimum ratio method. SOC was mainly segregated in PM2.5 and represented 53% - 75% of the total OC. A subset of EC data was compared with eBC measurements, showing a good correlation (R2 = 0.80), however, eBC concentrations were higher than EC concentrations of an average factor of 1.95 (+/- 0.55 standard deviation). This could be explained by the presence of a contribution of Brown Carbon (BrC), for example from biomass burning, in eBC measurements. Weekly patterns showed a slight decrease of carbon content during weekends with respect to weekdays especially

  2. PGE-Re concentrations in carbonaceous siltstones from the Barberton Drilling Project: Sources and processes

    Science.gov (United States)

    Rammensee, Philipp; Aulbach, Sonja

    2014-05-01

    The emergence, diversification and disappearance of Earth's life forms are closely tied to the redox state of the oceans, and the sources and sinks of metabolically cycled metals. It is generally accepted that the early terrestrial atmosphere contained extremely low levels of free oxygen [1]. While a significant change to atmospheric oxygen levels has been constrained to ca. 2.45 Ga ago, the details of the complex prior redox evolution of the oceans and atmosphere, and their influence on continental weathering, are still blurry [1]. Among the trace metals that have been applied to this problem, Re and the platinum-group elements (PGE) have variable redox chemistry that has been successfully exploited to identify detrital vs. hydrogenous sources and the presence of oxic vs. suboxic or euxinic conditions both in young and ancient sediments, including predominantly outcrop samples from the Barberton Greenstone Belt (BGB) [2,3]. As 187Re decays to 187Os, the Re-Os isotope system can additionally be used to date the deposition of carbonaceous shales through construction of isochrons and obtain the initial Os isotope composition, which is a tracer for continental input of radiogenic Os [4]. The sampling approach here was to choose 8+ samples from narrow intervals (≤1 m, to avoid initial Os isotope heterogeneity) from the Barberton Drilling Project (two depths in core BARB5/Fig Tree Group and one interval in core BARB3/Buck Reef Chert. We are currently finalising institution of the sample preparation and analytical techniques, involving (1) high-pressure asher digestion and (2) low-temperature leaching of presumably hydrogenous, acid-soluble components of spiked samples, followed by solvent extraction of Os and cation exchange column chromatography to isolate PGE-Re from the residue, further purification with BPHA and measurement of Ru-Pd-Ir-Pt by ICPMS and of Re-Os by MC-ICPMS. Preliminary tests with the SDO-1 standard have revealed that concentrations of Ir and Pt in

  3. Sources of PM2.5 carbonaceous aerosol in Riyadh, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Q. Bian

    2018-03-01

    Full Text Available Knowledge of the sources of carbonaceous aerosol affecting air quality in Riyadh, Saudi Arabia, is limited but needed for the development of pollution control strategies. We conducted sampling of PM2.5 from April to September 2012 at various sites in the city and used a thermo-optical semi-continuous method to quantify the organic carbon (OC and elemental carbon (EC concentrations. The average OC and EC concentrations were 4.7 ± 4.4 and 2.1 ± 2.5 µg m−3, respectively, during this period. Both OC and EC concentrations had strong diurnal variations, with peaks at 06:00–08:00 LT and 20:00–22:00 LT, attributed to the combined effect of increased vehicle emissions during rush hour and the shallow boundary layer in the early morning and at night. This finding suggested a significant influence of local vehicular emissions on OC and EC. The OC ∕ EC ratio in primary emissions was estimated to be 1.01, close to documented values for diesel emissions. Estimated primary organic carbon (POC and secondary organic carbon (SOC concentrations were comparable, with average concentrations of 2.0 ± 2.4 and 2.8 ± 3.4 µg m−3, respectively.We also collected 24 h samples of PM10 onto quartz microfiber filters and analyzed these for an array of metals by inductively coupled plasma atomic emission spectroscopy (ICP-AES. Total OC was correlated with Ca (R2 of 0.63, suggesting that OC precursors and Ca may have similar sources, and the possibility that they underwent similar atmospheric processing. In addition to a ubiquitous dust source, Ca is emitted during desalting processes in the numerous refineries in the region and from cement kilns, suggesting these sources may also contribute to observed OC concentrations in Riyadh. Concentration weighted trajectory (CWT analysis showed that high OC and EC concentrations were associated with air masses arriving from the Persian Gulf and the region around Baghdad, locations with

  4. Characteristics of size-resolved atmospheric inorganic and carbonaceous aerosols in urban Shanghai

    Science.gov (United States)

    Ding, X. X.; Kong, L. D.; Du, C. T.; Zhanzakova, A.; Fu, H. B.; Tang, X. F.; Wang, L.; Yang, X.; Chen, J. M.; Cheng, T. T.

    2017-10-01

    Size-segregated aerosol particles were collected with a 10-stage Micro-Orifice Uniform Deposit Impactor (MOUDI) at an urban site in Shanghai, China for four non-consecutive months representing four seasons from 2015 to 2016. Chemical composition, including water-soluble ions as well as organic carbon (OC), elemental carbon (EC) and secondary organic carbon (SOC) of size-resolved (0.056-18 μm) atmospheric aerosols in four seasons and in different polluted cases were studied. The size distributions of sulfate, nitrate and ammonium (SNA) and carbonaceous aerosol (OC, EC and SOC) were discussed and the potential sources of PM1.8-associated secondary species (SO42-, NO3-, SNA and SOC) in different seasons were identified by potential source contribution function (PSCF) model. Results showed that atmospheric ultrafine and fine particle pollution in Shanghai were very serious during the study period. Most of the water-soluble ions tended to be enriched in fine particles, especially being abundant in the droplet mode in polluted cases. Compared with sulfate, size distributions of nitrate and ammonium presented more significant seasonal variations and showed distinctive characteristics in polluted days. Abundant nitrate was concentrated in fine particles in cold seasons (spring and winter), whereas it was enriched in coarse mode during summer and autumn. The droplet mode sulfate with high concentration did not result in the aggravation of air pollution, while the nucleation mode sulfate may have made a great contribution to the air pollution in urban Shanghai. It was also found that the formation of air pollution in urban Shanghai had a significant link with nitrate and ammonium, especially with nitrate and ammonium in condensation mode and droplet mode, and the contribution of sulfate to the pollution formation in Shanghai would somehow be surpassed by the increasing nitrate and ammonium. OC and EC concentrations from spring to winter were found to be 11.10, 7.10, 12

  5. Sulfur dioxide and primary carbonaceous aerosol emissions in China and India, 1996–2010

    Directory of Open Access Journals (Sweden)

    Z. Lu

    2011-09-01

    Full Text Available China and India are the two largest anthropogenic aerosol generating countries in the world. In this study, we develop a new inventory of sulfur dioxide (SO2 and primary carbonaceous aerosol (i.e., black and organic carbon, BC and OC emissions from these two countries for the period 1996–2010, using a technology-based methodology. Emissions from major anthropogenic sources and open biomass burning are included, and time-dependent trends in activity rates and emission factors are incorporated in the calculation. Year-specific monthly temporal distributions for major sectors and gridded emissions at a resolution of 0.1°×0.1° distributed by multiple year-by-year spatial proxies are also developed. In China, the interaction between economic development and environmental protection causes large temporal variations in the emission trends. From 1996 to 2000, emissions of all three species showed a decreasing trend (by 9 %–17 % due to a slowdown in economic growth, a decline in coal use in non-power sectors, and the implementation of air pollution control measures. With the economic boom after 2000, emissions from China changed dramatically. BC and OC emissions increased by 46 % and 33 % to 1.85 Tg and 4.03 Tg in 2010. SO2 emissions first increased by 61 % to 34.0 Tg in 2006, and then decreased by 9.2 % to 30.8 Tg in 2010 due to the wide application of flue-gas desulfurization (FGD equipment in power plants. Driven by the remarkable energy consumption growth and relatively lax emission controls, emissions from India increased by 70 %, 41 %, and 35 % to 8.81 Tg, 1.02 Tg, and 2.74 Tg in 2010 for SO2, BC, and OC, respectively. Monte Carlo simulations are used to quantify the emission uncertainties. The average 95 % confidence intervals (CIs of SO2, BC, and OC emissions are estimated to be −16 %–17 %, −43 %–93 %, and −43 %–80 % for China, and −15 %–16 %, −41 %–87 %, and −44 %–92

  6. Sequence specificity of mutagenesis in the cI gene of bacteriophage lambda

    International Nuclear Information System (INIS)

    Skopek, T.R.; Wood, R.D.; Hutchinson, F.

    1985-01-01

    Studies of DNA base sequence alterations have shown that for every agent the mutagenic process is specific with respect to the types of base changes induced and the location of the changes in the DNA. Analysis of the types of mutations produced by mutagenic agents can provide insight into the mechanism of mutation and can suggest which DNA lesions may be involved in the actual mutagenic event. We have developed a system for the analysis of chemically induced base sequence alterations in the cI repressor gene of bacteriophage lambda using DNA sequencing techniques. To illustrate the utility of this type of analysis, we present the results obtained with ultraviolet light (UV). Irradiation of target DNA with UV alone, or UV followed by photoreactivating light (which removes dimers), produces mostly transitions at pyrimidine-pyrimidine sites. Conversely, irradiation with 313 nm light plus acetophenone (which produces only thymine dimers) produces mostly transversions at low efficiency. This and other evidence suggests that the actual premutagenic UV lesion in E. coli may not be pyrimidine-pyrimidine dimers, but rather pyr(6-4)pyo photoproducts

  7. Analysis of Individual Carbonaceous Particles Emitted from the Las Conchas Wildfire, Los Alamos, NM, in June-July 2011

    Science.gov (United States)

    Mazzoleni, C.; China, S.; Gorkowski, K.; Flowers, B. A.; Aiken, A. C.; Dubey, M. K.

    2012-12-01

    Carbonaceous aerosol emitted from biomass burning contributes significantly to atmospheric aerosol loadings regionally and globally. The net direct radiative forcing of biomass burning aerosol can be positive and/or negative and this depends on its composition, morphology and mixing state. Biomass burning aerosols can also change the cloud properties as they can act as cloud condensation nuclei. In this study we investigated biomass burning particles emitted from the Las Conchas wildfire in northern New Mexico that started on June 26, 2011 and burned an area of 245 square miles. Aerosol samples were collected on nucleopore filters at the Los Alamos National Laboratory during the third week of the wildfire event. Individual particles (~4000) were investigated using field-emission scanning electron microscopy and energy dispersive X-ray spectroscopy (EDS) to distinguish different carbonaceous particles and their shape, size, elemental composition and mixing state. A thermo-denuder was used to remove compounds that are volatile at temperatures up to 200 C, leaving behind the black carbon and any compounds that did not volatize completely. Smoke particles consisted of a) tar balls, which are amorphous spherical carbonaceous organic aerosols; b) organic particles with inorganic inclusions, c) soot particles and (d) soot with various inclusions. Two distinct kinds of tar balls, "electronically" dark and bright, were found using the field-emission scanning electron microscopy and were characterized for ambient and denuded conditions to understand coating effects and aging. It was found that dark tar balls are generally larger in size than the bright ones. Additionally, the difference between the size of ambient-bright and the size of denuded-bright tar balls was larger than the difference between the size of ambient-dark and the size of denuded-dark tar balls. EDS analysis showed that 70% of the dark tar balls had higher (~60%) relative oxygen content than in the bright

  8. As ciências naturais e as ciências do espírito na era da globalização

    Directory of Open Access Journals (Sweden)

    Jaeschke, Walter

    2006-01-01

    Full Text Available Este artigo, o autor apresenta, primeiramente, reflexões de cunho histórico sobre a relação entre as Ciências Naturais e as Ciências do Espírito, seguidas de observações, de caráter mais sistemático, sobre o conceito das próprias Ciências do Espírito. Com fundamento nessas observações, tece algumas reflexões sobre até que ponto podemos esperar da globalização efeitos sobre as Ciências Naturais e as Ciências do Espírito

  9. 3-D assessment of peak-metamorphic conditions by Raman spectroscopy of carbonaceous material: an example from the margin of the Lepontine dome (Swiss Central Alps)

    DEFF Research Database (Denmark)

    Wiederkehr, Michael; Bousquet, Romain; Ziemann, Martin

    2011-01-01

    This study monitors regional changes in the crystallinity of carbonaceous matter (CM) by applying Micro-Raman spectroscopy to a total of 214 metasediment samples (largely so-called Bu¨ndnerschiefer) dominantly metamorphosed under blueschist- to amphibolite-facies conditions. They were collected...

  10. Carbonaceous species in PM2.5 and PM10 in urban area of Zhengzhou in China: Seasonal variations and source apportionment

    Science.gov (United States)

    Wang, Qun; Jiang, Nan; Yin, Shasha; Li, Xiao; Yu, Fei; Guo, Yue; Zhang, Ruiqin

    2017-07-01

    PM2.5 and PM10 samples were simultaneously collected in an urban site in Zhengzhou, China from October 2014 to July 2015 representing the four seasons. Organic carbon (OC), elemental carbon (EC), and non-polar organic compounds including n-alkanes (C8-C40) and polycyclic aromatic hydrocarbons (PAHs) were quantified. The characteristics of their concentrations, seasonal variations, and sources of n-alkanes and PAHs were investigated. Diagnostic ratios and positive matrix factorization (PMF) were used to characterize carbonaceous species, identify their possible sources, and apportion the contributions from each possible source. The concentrations of the components exhibited distinct seasonal variation, that is, the concentrations are high in winter and low in summer. This finding could be associated with increase in air pollutant emissions during heating season and stable weather condition. The estimated total carbonaceous aerosol accounts for 32% of PM2.5 and 30% of PM10. Hence, carbonaceous compounds were the major components of particulate matter in the study area. Moreover, OC, EC, PAHs, and n-alkanes preferentially accumulated into fine particles. The carbonaceous components exhibited high correlation in PM2.5 and PM10, thereby indicating that their sources were similar. The PMF results revealed that the main sources of PAHs were coal combustion (40%) and motor vehicles (29%); n-alkanes were mainly from burning of fossil fuel (48%). These sources were consistent with the diagnostic ratios obtained. This study provides guidance for improving air quality and reducing human exposure to toxic air pollutants.

  11. Porous nitrogen-enriched carbonaceous material from marine waste: chitosan-derived layered CNX catalyst for aerial oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid

    Science.gov (United States)

    Chitosan derived porous layered nitrogen-enriched carbonaceous CNx catalyst (PLCNx) has been synthesized from marine waste and its use demonstrated in a metal-free heterogeneous selective oxidation of 5-hydroxymethyl-furfural (HMF) to 2,5-furandicarboxylic acid (FDCA) using aeria...

  12. Escrevendo em aulas de ciências Writing in science classes

    Directory of Open Access Journals (Sweden)

    Carla Marques Alvarenga de Oliveira

    2005-12-01

    Full Text Available Neste artigo, apresentamos uma análise dos registros escritos dos alunos do 3° ano do Ensino Fundamental nas aulas de Ciências, em que a professora utilizou as atividades de conhecimento físico, criadas pelo Laboratório de Pesquisa e Ensino de Física da Faculdade de Educação da Universidade de São Paulo. Os registros analisados foram coletados na Escola de Aplicação da Feusp, no ano de 2001, durante o acompanhamento de três aulas de Ciências: o problema do submarino, o problema do barquinho e o problema da pressão. O artigo procura mostrar um panorama de como aparecem os registros realizados pelos alunos, após uma aula de Ciências em que eles são levados a resolver situações problemáticas por meio da experimentação, argumentar e escrever sobre os fenômenos físicos. Durante a análise, levou-se em consideração os tipos de textos que os alunos escrevem, o uso da primeira pessoa, o uso de verbos de ação, o respeito à ordem cronológica dos eventos e quais os tipos de explicações os alunos atribuem aos fenômenos trabalhados.This article analyzed the written records of Third Grade students of Elementary School at Escola de Aplicação, Universidade de São Paulo, gathered during the Science classes of the 2001 school year, in which activities about physical understanding were used. Created by the Laboratory of Research and Teaching of Physics - LAPEF, of the College of Education of USP, the activities "The Problem of the Submarine", "The Problem of the Little Boat" and "The Problem of the Pressure" required the students to solve problematic situations through experimentation, developing arguments and write about the phenomena. The study developed a framework of how the records are presented by the students, considering the types of texts they produce, the use of the first person, the use of verbs of action, the respect of the chronological order of events and the types of explanations the students give for the

  13. Quantification of the carbonaceous matter origin in submicron marine aerosol by 13C and 14C isotope analysis

    Directory of Open Access Journals (Sweden)

    M. Ramonet

    2011-08-01

    Full Text Available Dual carbon isotope analysis of marine aerosol samples has been performed for the first time demonstrating a potential in organic matter apportionment between three principal sources: marine, terrestrial (non-fossil and fossil fuel due to unique isotopic signatures. The results presented here, utilising combinations of dual carbon isotope analysis, provides conclusive evidence of a dominant biogenic organic fraction to organic aerosol over biologically active oceans. In particular, the NE Atlantic, which is also subjected to notable anthropogenic influences via pollution transport processes, was found to contain 80 % organic aerosol matter of biogenic origin directly linked to plankton emissions. The remaining carbonaceous aerosol was of terrestrial origin. By contrast, for polluted air advected out from Europe into the NE Atlantic, the source apportionment is 30 % marine biogenic, 40 % fossil fuel, and 30 % continental non-fossil fuel. The dominant marine organic aerosol source in the atmosphere has significant implications for climate change feedback processes.

  14. Magnesium and 54Cr isotope compositions of carbonaceous chondrite chondrules – Insights into early disk processes

    DEFF Research Database (Denmark)

    Olsen, Mia Bjørg Stolberg; Wielandt, Daniel Kim Peel; Schiller, Martin

    2016-01-01

    typically observed for bulk carbonaceous chondrites. Collectively, these observations suggest that the CV chondrules formed from precursors that originated in various regions of the protoplanetary disk and were then transported to the accretion region of the CV parent asteroid whereas CR chondrule...... establishes that these objects formed from a thermally unprocessed and 26Al-poor source reservoir distinct from most inner Solar System asteroids and planetary bodies, possibly located beyond the orbits of the gas giants. In contrast, a large fraction of the CV chondrules plot on the inner Solar System...... correlation line, indicating that these objects predominantly formed from thermally-processed, 26Al-bearing precursor material akin to that of inner Solar System solids, asteroids and planets....

  15. Quantification of the carbonaceous matter origin in submicron marine aerosol by 13C and 14C isotope analysis

    Science.gov (United States)

    Ceburnis, D.; Garbaras, A.; Szidat, S.; Rinaldi, M.; Fahrni, S.; Perron, N.; Wacker, L.; Leinert, S.; Remeikis, V.; Facchini, M. C.; Prevot, A. S. H.; Jennings, S. G.; Ramonet, M.; O'Dowd, C. D.

    2011-08-01

    Dual carbon isotope analysis of marine aerosol samples has been performed for the first time demonstrating a potential in organic matter apportionment between three principal sources: marine, terrestrial (non-fossil) and fossil fuel due to unique isotopic signatures. The results presented here, utilising combinations of dual carbon isotope analysis, provides conclusive evidence of a dominant biogenic organic fraction to organic aerosol over biologically active oceans. In particular, the NE Atlantic, which is also subjected to notable anthropogenic influences via pollution transport processes, was found to contain 80 % organic aerosol matter of biogenic origin directly linked to plankton emissions. The remaining carbonaceous aerosol was of terrestrial origin. By contrast, for polluted air advected out from Europe into the NE Atlantic, the source apportionment is 30 % marine biogenic, 40 % fossil fuel, and 30 % continental non-fossil fuel. The dominant marine organic aerosol source in the atmosphere has significant implications for climate change feedback processes.

  16. Early solar system. Early accretion of water in the inner solar system from a carbonaceous chondrite-like source.

    Science.gov (United States)

    Sarafian, Adam R; Nielsen, Sune G; Marschall, Horst R; McCubbin, Francis M; Monteleone, Brian D

    2014-10-31

    Determining the origin of water and the timing of its accretion within the inner solar system is important for understanding the dynamics of planet formation. The timing of water accretion to the inner solar system also has implications for how and when life emerged on Earth. We report in situ measurements of the hydrogen isotopic composition of the mineral apatite in eucrite meteorites, whose parent body is the main-belt asteroid 4 Vesta. These measurements sample one of the oldest hydrogen reservoirs in the solar system and show that Vesta contains the same hydrogen isotopic composition as that of carbonaceous chondrites. Taking into account the old ages of eucrite meteorites and their similarity to Earth's isotopic ratios of hydrogen, carbon, and nitrogen, we demonstrate that these volatiles could have been added early to Earth, rather than gained during a late accretion event. Copyright © 2014, American Association for the Advancement of Science.

  17. DNA damage in isolated rat hepatocytes exposed to C.I. pigment orange 5 and C.I. pigment yellow 12 by the alkaline comet assay

    DEFF Research Database (Denmark)

    Møller, P; Wallin, Håkan; Grunnet, N

    1998-01-01

    , and C.I. pigment orange 5 is a naphthol-azo pigment. The pigments are virtually insoluble in aqueous solutions, and they have not been tested extensively for toxicological effects. C.I. pigment orange 5 increased the levels of DNA damage at 5 microg/ml (P pigment yellow 12 at 20 microg....../ml (P effect of incubation time (20, 40, and 80 min) of the same concentrations of the pigments was tested. The levels of DNA damage were increased up to 80 min. Both pigments produced DNA damage that was in the same range as the food carcinogen 2-amino-3,8-dimethylimidazo[4,5-f......The induction of DNA damage by commonly used printing ink pigments, C.I. pigment orange 5 (C.I. 12075) and C.I. pigment yellow 12 (C.I. 21090), was investigated in freshly isolated rat hepatocytes with the comet assay. C.I. pigment yellow 12 is a 3,3'-dichlorobenzidine-based diarylide pigment...

  18. Radiative Forcing Due to Enhancements in Tropospheric Ozone and Carbonaceous Aerosols Caused by Asian Fires During Spring 2008

    Science.gov (United States)

    Natarajan, Murali; Pierce, R. Bradley; Lenzen, Allen J.; Al-Saadi, Jassim A.; Soja, Amber J.; Charlock, Thomas P.; Rose, Fred G.; Winker, David M.; Worden, John R.

    2012-01-01

    Simulations of tropospheric ozone and carbonaceous aerosol distributions, conducted with the Real-time Air Quality Modeling System (RAQMS), are used to study the effects of major outbreaks of fires that occurred in three regions of Asia, namely Thailand, Kazakhstan, and Siberia, during spring 2008. RAQMS is a global scale meteorological and chemical modeling system. Results from these simulations, averaged over April 2008, indicate that tropospheric ozone column increases by more than 10 Dobson units (DU) near the Thailand region, and by lesser amounts in the other regions due to the fires. Widespread increases in the optical depths of organic and black carbon aerosols are also noted. We have used an off-line radiative transfer model to evaluate the direct radiative forcing due to the fire-induced changes in atmospheric composition. For clear sky, the monthly averaged radiative forcing at the top of the atmosphere (TOA) is mostly negative with peak values less than -12 W/sq m occurring near the fire regions. The negative forcing represents the increased outgoing shortwave radiation caused by scattering due to carbonaceous aerosols. At high latitudes, the radiative forcing is positive due to the presence of absorbing aerosols over regions of high surface albedo. Regions of positive forcing at TOA are more pronounced under total sky conditions. The monthly averaged radiative forcing at the surface is mostly negative, and peak values of less than -30 W/sq m occur near the fire regions. Persistently large negative forcing at the surface could alter the surface energy budget and potentially weaken the hydrological cycle.

  19. Sources of non-fossil-fuel emissions in carbonaceous aerosols during early winter in Chinese cities

    Directory of Open Access Journals (Sweden)

    D. Liu

    2017-09-01

    Full Text Available China experiences frequent and severe haze outbreaks from the beginning of winter. Carbonaceous aerosols are regarded as an essential factor in controlling the formation and evolution of haze episodes. To elucidate the carbon sources of air pollution, source apportionment was conducted using radiocarbon (14C and unique molecular organic tracers. Daily 24 h PM2. 5 samples were collected continuously from October 2013 to November 2013 in 10 Chinese cities. The 14C results indicated that non-fossil-fuel (NF emissions were predominant in total carbon (TC; average  =  65 ± 7 %. Approximately half of the EC was derived primarily from biomass burning (BB (average  =  46 ± 11 %, while over half of the organic carbon (OC fraction comprised NF (average  =  68 ± 7 %. On average, the largest contributor to TC was NF-derived secondary OC (SOCnf, which accounted for 46 ± 7 % of TC, followed by SOC derived from fossil fuels (FF (SOCf; 16 ± 3 %, BB-derived primary OC (POCbb; 13 ± 5 %, POC derived from FF (POCf; 12 ± 3 %, EC derived from FF (ECf; 7 ± 2 % and EC derived from BB (ECbb; 6 ± 2 %. The regional background carbonaceous aerosol composition was characterized by NF sources; POCs played a major role in northern China, while SOCs contributed more in other regions. However, during haze episodes, there were no dramatic changes in the carbon source or composition in the cities under study, but the contribution of POC from both FF and NF increased significantly.

  20. Removal of Cr(III) from chrome tanning wastewater by adsorption using two natural carbonaceous materials: Eggshell and powdered marble.

    Science.gov (United States)

    Elabbas, Saliha; Mandi, Laila; Berrekhis, Fatima; Pons, Marie Noelle; Leclerc, Jean Pierre; Ouazzani, Naaila

    2016-01-15

    In the present paper, eggshell and powdered marble, two carbonaceous materials, were used to remove Cr(III) ions from a real chrome tanning wastewater. The effects of initial effluent pH, adsorbent dose, contact time and temperature were studied. The maximum uptake of chromium ions was obtained at pH 5.0 with the dose 20 g L(-1) and 12 g L(-1) for eggshell and powdered marble respectively. Adsorption equilibrium was reached after 14 h contact time for eggshell and only after 30 min for powdered marble. Under these conditions, almost 99% Cr(III) was removed from chrome tanning wastewater having an initial concentration of chromium of 3.21 g L(-1). Kinetic data were satisfactorily described by a pseudo-second order chemical sorption model. The equilibrium rate constant was notably greater for powdered marble than for eggshell with 1.142·10(-3) (g mg(-1) min(-1)) and 0.041·10(-3) (g mg(-1) min(-1)) respectively. The adsorption isotherm were well described by a Langmuir model and showed that the interaction of chromium with the two adsorbents surface is a localized monolayer adsorption with a smaller energy constant for the powdered marble than for eggshell (0.020 (L mg(-1)) and 0.083 (L mg(-1)) respectively). The powdered marble was able to adsorb faster a large amount of Cr (III) in comparison to eggshell. The use of a standardized lettuce seed bioassay allowed evaluating a better effectiveness of the Cr adsorption on the powdered marble, removing up to 40% of the treated effluent toxicity than by eggshell 25%. The powdered marble could be considered as an effective, low cost carbonaceous material to be used for chromium removal from tanning wastewater. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Parametric effects and optimization on synthesis of iron (II) doped carbonaceous catalyst for the production of biodiesel

    International Nuclear Information System (INIS)

    Dhawane, Sumit H.; Kumar, Tarkeshwar; Halder, Gopinath

    2016-01-01

    Highlights: • Iron (II) was doped on activated carbon surface. • L9 orthogonal array was used for experimental design using Taguchi approach. • Parametric effects of catalyst synthesis on biodiesel yield were studied. • Agitation speed was emerged as most influential parameter. • Cost analysis of catalyst shows it is cost effective and eco-friendly. - Abstract: Synthesis of efficient and low cost heterogeneous catalyst for transesterification of triglycerides into esters is the need of the hour. The present study elaborates an indigenous development of ferromagnetic iron (II) doped carbonaceous catalyst (Fe/C) for the production of biodiesel from rubber seed oil. The parametric effects on the synthesis of Fe/C catalyst were studied to identify the most significant parameters affecting the biodiesel yield using Taguchi method. The doping process was optimised for maximum biodiesel yield considering four parameters viz. Impregnation time, temperature, catalyst content and agitation speed. The prepared catalyst was characterized using scanning electron microscopy (SEM), X-ray energy dispersive analysis (EDX), X-ray diffraction (XRD), thermo gravimetric analysis (TGA) and Fourier transform infrared spectrometer (FT-IR). The contribution factor revealed that agitation speed is the most influential parameter affecting the biodiesel yield followed by catalyst content, impregnation time and temperature. The maximum biodiesel yield observed in optimum condition of impregnation time 15 h, impregnation temperature 40 °C, catalyst content 5 wt% and agitation speed 500 rpm was 96.31%. The cost analysis of catalyst synthesis was done and found to be fairly economical. The reusability of the catalyst was tested to check the decay in catalytic activity at the optimised condition and found to decrease in activity by 0.8–1.2% after three cycles. Thus, the experimental results and characterization study confirm that indigenously developed carbonaceous catalyst from waste

  2. The mercury species and their association with carbonaceous compositions, bromine and iodine in PM2.5 in Shanghai.

    Science.gov (United States)

    Duan, Lian; Xiu, Guangli; Feng, Ling; Cheng, Na; Wang, Chenggang

    2016-03-01

    PM2.5 samples were collected in south Shanghai from November 2013 to October 2014. The species of particulate bounded mercury (PBM), including hydrochloric soluble particle-phase mercury (HPM), element soluble particle-phase mercury (EPM) and residual soluble particle-phase mercury (RPM), were determined in PM2.5. The chemical composition of PM2.5 including organic carbon (OC) and elemental carbon (EC), total bromine and iodine were also analyzed. The results showed that the annual average concentration of PBM was 0.30 ± 0.31 ng m(-3) and 0.34 ± 0.32 ng m(-3) in winter, 0.31 ± 0.19 ng m(-3) in spring, 0.30 ± 0.45 ng m(-3) in fall and 0.28 ± 0.17 ng m(-3) in summer. HPM took the highest fraction 51.2% in PBM, followed by RPM 27.7% and EPM 21.1%. EC positively correlated to particle mercury, especially in winter (r = 0.70), the same for OC in winter (r = 0.72), which indicated that the carbonaceous composition may affect the transformation of Hg in the atmosphere. Mercury species showed different correlations with bromine and iodine in the four seasons. The strongest correlation between bromine, iodine and mercury was found in spring and fall, respectively. Bromine showed the stronger correlation with total mercury and speciated particle mercury than iodine. In addition, the days were classified into haze and non-haze days based on the visibility and relative humidity, while the ratio of HPM in haze days was much higher than that in non-haze days. EC strongly correlated with PBM during haze and non-haze days while OC only positively correlated with PBM in non-haze days, this may indicate that the different carbonaceous part may affect PBM differently. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Simulating the formation of carbonaceous aerosol in a European Megacity (Paris during the MEGAPOLI summer and winter campaigns

    Directory of Open Access Journals (Sweden)

    C. Fountoukis

    2016-03-01

    Full Text Available We use a three-dimensional regional chemical transport model (PMCAMx with high grid resolution and high-resolution emissions (4 × 4 km2 over the Paris greater area to simulate the formation of carbonaceous aerosol during a summer (July 2009 and a winter (January/February 2010 period as part of the MEGAPOLI (megacities: emissions, urban, regional, and global atmospheric pollution and climate effects, and Integrated tools for assessment and mitigation campaigns. Model predictions of carbonaceous aerosol are compared against Aerodyne aerosol mass spectrometer and black carbon (BC high time resolution measurements from three ground sites. PMCAMx predicts BC concentrations reasonably well reproducing the majority (70 % of the hourly data within a factor of two during both periods. The agreement for the summertime secondary organic aerosol (OA concentrations is also encouraging (mean bias = 0.1 µg m−3 during a photochemically intense period. The model tends to underpredict the summertime primary OA concentrations in the Paris greater area (by approximately 0.8 µg m−3 mainly due to missing primary OA emissions from cooking activities. The total cooking emissions are estimated to be approximately 80 mg d−1 per capita and have a distinct diurnal profile in which 50 % of the daily cooking OA is emitted during lunch time (12:00–14:00 LT and 20 % during dinner time (20:00–22:00 LT. Results also show a large underestimation of secondary OA in the Paris greater area during wintertime (mean bias =  −2.3 µg m−3 pointing towards a secondary OA formation process during low photochemical activity periods that is not simulated in the model.

  4. CI in the work place: does involving the HRM function make any difference?

    DEFF Research Database (Denmark)

    Hyland, Paul; Becker, Karen; Sload, Terry

    2008-01-01

    People are central to successful Continuous Improvement (CI), and in larger organisations a Human Resource Management (HRM) function is responsible for people related issues. Central to CI is learning and a culture that supports CI. Learning needs to be both individual and organisational, and must...... benefit the organisation's performance. The HRM function is often given the task of championing cultural change and managing aspects of training and learning, and it would appear that involvement of HRM professionals would enhance CI efforts and assist in the timely solution of issues within the CI...

  5. DNA damage in isolated rat hepatocytes exposed to C.I. pigment orange 5 and C.I. pigment yellow 12 by the alkaline comet assay

    DEFF Research Database (Denmark)

    Møller, P; Wallin, Håkan; Grunnet, N

    1998-01-01

    , and C.I. pigment orange 5 is a naphthol-azo pigment. The pigments are virtually insoluble in aqueous solutions, and they have not been tested extensively for toxicological effects. C.I. pigment orange 5 increased the levels of DNA damage at 5 microg/ml (P .../ml (P effect of incubation time (20, 40, and 80 min) of the same concentrations of the pigments was tested. The levels of DNA damage were increased up to 80 min. Both pigments produced DNA damage that was in the same range as the food carcinogen 2-amino-3,8-dimethylimidazo[4,5-f......]quinoxaline. Our data indicate that both C.I. pigment orange 5 and C.I. pigment yellow 12 are genotoxic in hepatocytes with metabolizing capacities. However, further investigation of the metabolism and disposition are required for the evaluation of the safety of these pigments....

  6. Ciência 2.0: uma experiência em comunicação e em jornalismo de ciência

    OpenAIRE

    Renata Sofia Gomes da Silva

    2012-01-01

    O presente documento versa sabre uma experiência de três meses de estágio, em comunicação e em jornalismo de ciência, entre novembro de 2011 e janeiro de 2012, no Ciência 2.0, urn projeto que aposta na comunicação e divulgação da ciência através de conteúdos multiplataforma. Trata-se de uma iniciativa levada a cabo na Universidade do Porto que pretende aproximar a Ciência da sociedade,conferindo uma dimensão explicativa a varios temas de interesse através de meios como o áudio,vídeo, infograf...

  7. The functional significance of cortical reorganization and the parallel development of CI therapy

    Directory of Open Access Journals (Sweden)

    Edward eTaub

    2014-06-01

    Full Text Available For the 19th and the better part of the 20th centuries two correlative beliefs were strongly held by almost all neuroscientists and practitioners in the field of neurorehabilitation. The first was that after maturity the adult CNS was hardwired and fixed, and second that in the chronic phase after CNS injury no substantial recovery of function could take place no matter what intervention was employed. However, in the last part of the 20th century evidence began to accumulate that neither belief was correct. First, in the 1960s and 1970s, in research with primates given a surgical abolition of somatic sensation from a single forelimb, which rendered the extremity useless, it was found that behavioral techniques could convert the limb into an extremity that could be used extensively. Beginning in the late 1980s, the techniques employed with deafferented monkeys were translated into a rehabilitation treatment, termed Constraint Induced Movement therapy or CI therapy, for substantially improving the motor deficit of the upper and lower extremities in the chronic phase after stroke. CI therapy has been applied successfully to other types of damage to the CNS such as traumatic brain injury, cerebral palsy, multiple sclerosis, and spinal cord injury, and it has also been used to improve function in focal hand dystonia and for aphasia after stroke. As this work was proceeding, it was being shown during the 1980s and 1990s that sustained modulation of afferent input could alter the structure of the CNS and that this topographic reorganization could have relevance to the function of the individual. The alteration in these once fundamental beliefs has given rise to important recent developments in neuroscience and neurorehabilitation and holds promise for further increasing our understanding of CNS function and extending the boundaries of what is possible in neurorehabilitation.

  8. A Science Centre as a Geoturism promoter - the Lagos Ciência Viva examples (Portugal).

    Science.gov (United States)

    Azevedo Rodrigues, Luis; Leote, Catarina

    2017-04-01

    Science outreach and engagement are crucial core objectives of the Lagos Ciência Viva Science Centre (CCVL). By engaging audiences in the real world a link is made between their science centre experience and the environment in which they live. Therefore, it has been an option of the CCVL to offer geological outdoor activities, both in the natural environment and urban context. Dinosaurs are an appealing science subject for both students and tourists. Thus, the CCVL has a long tradition in organizing and guiding field trips to two dinosaur track sites - Salema and Santa beaches (Vila do Bispo, southwest Algarve). These sites, both from the Lower Cretaceous reveal at least two types of tracks - theropod and iguanodontian footprints. Often in combination with the paleontology field trips, the CCVL also offers different geological field trips both for formal (school) and informal (tourism) education. This allows students and tourists to be introduced to dinosaur paleobiology and ichnology and to the structural geology and stratigraphy of the area. Our science outreach is being further developed by contractual agreement with a regional tour operator, in which the CCVL is responsible for the scientific content and guidance of the visits. Aiming at an urban context, the CCVL produced three Urban Geology and Paleontology Guide Books for three Algarve cities (Lagos, Faro and Tavira), which can be acquired in the three Ciência Viva Science Centres shops as well as in the tourist information offices serving this way as a basis for guided urban tours also offered by the CCVL. Based on our experience, we review and contextualise these geoscience activities and their potential for science outreach, communication and tourism. We discuss and propose a classification of different possibilities in geoscience communication and outreach based on three vertices: Science, Heritage and Geotourism. Some particularities of these visits, such as the merge between geosciences and other

  9. As tendências atuais dos paradigmas: ciência, tecnologia e sociedade e ensino de ciências indígena no VII ENPEC

    Directory of Open Access Journals (Sweden)

    Maria Delourdes Maciel

    2014-01-01

    Full Text Available O Encontro Nacional de Pesquisas em Educação em Ciências é um evento bianual organizada pelos pesquisadores do ensino de Ciências. O objetivo principal desse encontro é reunir os professores e pesquisadores da área, para socializarem os relatos de experiência e pesquisas no ensino de Ciências. Nesse presente trabalho, foi realizado um mapeamento dos artigos apresentados nas seções de comunicação oral do VII ENPEC, somando um total de 425 artigos selecionados, procurou-se identificar os relacionados com a abordagem Ciências, Tecnologia e Sociedade (CTS no ensino de Ciências sua estrutura de organização e o numero de pesquisadores dessa área do Ensino de Ciências. Para esse estudo foi realizado uma pesquisa qualitativa de caráter bibliográfico, e para a análise dos dados buscou-se subsídios teóricos em Fiorentini (2002 e Bardin (2006 porque assim seria possível comparar minuciosamente os diferentes resultados obtidos. Conclui-se que a linha de pesquisa com a temática CTS apresentou 28 trabalhos cerca de 7% de trabalhos apresentados, confirmando uma sinalização nessa área de pesquisa pelos pesquisadores do ensino de Ciências e a temática sobre ensino de ciências indígena representou cerca de 1% dos trabalhos apresentados.

  10. A natureza da ciência nos currículos de ciências — Estudo do currículo de Ciências Naturais do 3º ciclo do ensino básico

    OpenAIRE

    Ferreira, Sílvia; Morais, Ana Maria

    2018-01-01

    O estudo analisa em que medida a mensagem sociológica transmitida pelo Discurso Pedagógico Oficial veiculado no currículo de Ciências Naturais do 3º ciclo do ensino básico português contempla a natureza da ciência. A investigação apresenta pressupostos epistemológicos e sociológicos e está particularmente baseada na teoria do discurso pedagógico de Bernstein e na conceptualização de Ziman sobre a construção da ciência. O estudo usou uma metodologia mista e seguiu um processo dialéctico entre ...

  11. Study of the carbonaceous fraction of the atmospheric aerosol in Chamonix and St Jean de Maurienne: seasonal evolutions, source and chemical characteristics; Etude de la fraction carbonee de l'aerosol atmospherique a Chamonix et St Jean de Maurienne: evolutions saisonnieres, sources et caracteristiques chimiques

    Energy Technology Data Exchange (ETDEWEB)

    Aymoz, G.

    2005-03-15

    The atmospheric aerosols play an important role in the earth climatic system. They are also at the origin of air pollution problems in urban areas. However, their influence on the global climactic change, as well as their chemical properties in urban zone, is still very poorly known. One of the main reasons to that is the lack of information on one of the major components of aerosol, the carbonaceous matter. This work focuses on a better knowledge of this particulate carbonaceous matter. This study presents measurements of carbonaceous matter (OC and EC) in aerosol (PM10) performed within the framework of the program POVA, between February 2001 and June 2003 in Chamonix and St Jean de Maurienne (French Alps). This series represents one of the first of this type for basic sites of alpine valleys, characterized by emissions located in the bottom of the valleys and strong temperature inversions in winter, limiting the dispersion of pollutants. The POVA program, centred on the study of air pollution in these valleys, was proposed following the closing of the 'Tunnel du Mont Blanc', in 1999. One of the main objectives was to evaluate the sources of pollution by particles, in particular the share due to the international heavy duty traffic. We could establish that, on the two sites and while the international heavy duty traffic was not restored in the Chamonix Valley, this source represented approximately a third of the observed mass of particles, and was at the origin of a weaker fraction of the carbonaceous matter mass. The extremely primary character of the carbonaceous matter is a remarkable specificity of our sites. The source of carbonaceous matter represented by light vehicles emissions could not be studied. Then, it appears that combustion of biomass (probably from fireplaces) plays an important role, increased in the case of low temperatures, on the levels of pollution by particles. Lastly, the potential impact of the semi-volatile matter condensation

  12. Rytų baltų CiR tipo veiksmažodžiai

    Directory of Open Access Journals (Sweden)

    Dalia Pakalniškienė

    2011-12-01

    Full Text Available EASTERN BALTIC CiR TYPE VERBSSummaryThis article analyzes CiR type verbs in the Eastern Baltic languages and attempts to explain their origin and evolution. The criterion for inclusion as a subject for investigation – the root structure – allows for the discovery of general patterns in the history of verbs of the given structural type and the development of these verbs in the separate Baltic languages, and can provide a better definition of archaic features and innovations, because the root structure is closely related to the morphological structure and categorial semantics (especially in the Lithuanian language.According to various sources, there are approximately 30 CiR type verbs common to the Eastern Baltic languages (there are more in the Lithuanian language.In regard to morphological structure these are rather varied: a-stem, ia-stem, infix and sta-stem (the morphological structure also depends on the root final element: Cin are a-stem, Cir, Cil ia-stem or sto-stem, Cim are sta-stem.l. The largest group consists of infix and sta-stem verbs (15.1.1. The majority of these form diathetic pairs with ia-stem verbs (10. The categorial semantics of infix and sta-stem verbs – the mutative meaning – is opposed to the causative meaning of ia-stem verbs, e.g. Lith. bẽria / bỹra : Latv. ber̦u / bir̃stu. This opposition has not been documented in the Old Prussian language.1.2. Several of the verbs preserve Indo-European roots (5, but differ in morphological structure, these being infix and sta-stems or crossovers from a-stems, e.g.: Lith. mìršta : Latv. mir̃stu, Lith. gìmsta // gẽma : Latv. dzìmstu // dzemu.2. Only half as many ia-stem CiR type verbs have been discovered (7, e.g. Lith. skìria – skýrė : Latv. šķir̦u – šķîru.3. Eight Eastern Baltic a-stem verbs have CiR type roots.3.1. Mostly a-stem verbs with quantitative vowel changes were identified (6. In the Latvian language the preterite may occur without

  13. Max Weber e a objetividade do conhecimento nas ciências da cultura: um breve guia para o texto A ‘Objetividade’ do Conhecimento na Ciência Social e na Ciência Política (1904

    Directory of Open Access Journals (Sweden)

    Jean Henrique Costa

    2011-05-01

    Full Text Available

    O presente artigo objetiva discutir o sentido da objetividade do conhecimento empírico-social na obra de Max Weber, especificamente no texto “A ‘Objetividade’ do Conhecimento na Ciência Social e na Ciência Política”, de 1904. Discute-se, no primeiro momento, a distinção entre conhecimento empírico e juízo de valor; no segundo momento, faz-se uma rápida crítica às idéias de “lei” e “conexão regular” nas ciências sociais para, em seguida, na terceira parte, discutir a estrutura da formação dos conceitos típico-ideais como recursos metodológicos, nos quais, para Weber, expressam a possibilidade da validade objetiva do conhecimento nas ciências da cultura.

  14. Quantum entanglement of helium-like systems with varying-Z: compact state-of-the-art CI wave functions

    Science.gov (United States)

    López-Rosa, S.; Esquivel, R. O.; Plastino, A. R.; Dehesa, J. S.

    2015-09-01

    In this work we have performed state-of-the-art configuration-interaction (CI) calculations to determine the linear and von Neumann entanglement entropies for the helium-like systems with varying nuclear charge Z in the range 1≤slant Z≤slant 10. The focus of the work resides on determining accurate entanglement values for 2-electron systems with the lowest computational cost through compact CI-wave functions. Our entanglement results for the helium atom fully agree with the results obtained with higher quality wave functions of the Kinoshita type (Dehesa [5]). We find that the correlation energy is linearly related to the entanglement measures associated with the linear and von Neumann entropies of the single-particle reduced density matrizes, which sheds new light on the physical implications of entanglement in helium-like systems. Moreover, we report CI-wave-function-based benchmark results for the entanglement values for all members of the helium isoelectronic series with an accuracy similar to that of Kinoshita-type wave functions. Finally, we give parametric expressions of the linear and von Neumann entanglement measures for two-electron systems as Z varies from 1 to 10.

  15. Por uma sociologia crítica da ciência

    OpenAIRE

    Jarvie,Ian; Agassi,Joseph

    2011-01-01

    Neste artigo crítico e construtivo, defendemos que a Sociologia da Ciência, como está estabelecida, é distorcida por uma suposta filosofia idealista que estimula uma atitude acrítica em relação ao que se supõe serem fatos. Propomos uma sociologia crítica da ciência que faz a distinção entre ciência, ciência aplicada e tecnologia; enfoca a falibilidade da ciência e da sociologia da ciência que desconstrói toda pretensão de autoridade. Construtivamente, esboçamos os elementos de uma sociologia ...

  16. Characterization of carbonaceous aerosols during the MINOS campaign in Crete, July–August 2001: a multi-analytical approach

    Directory of Open Access Journals (Sweden)

    J. Sciare

    2003-01-01

    Full Text Available During the major part of the Mediterranean Intensive Oxidant Study (MINOS campaign (summer 2001, Crete Isl., the Marine Boundary Layer (MBL air was influenced by long range transport of biomass burning from the northern and western part of the Black Sea. During this campaign, carbonaceous aerosols were collected on quartz filters at a Free Tropospheric (FT site, and at a MBL site together with size-resolved distribution of aerosols. Three Evolution Gas Analysis (EGA protocols have been tested in order to better characterize the collected aged biomass burning smoke: A 2-step thermal method (Cachier et al., 1989 and a thermo-optical technique using two different temperature programs. The later temperature programs are those used for IMPROVE (Interagency Monitoring of Protected Visual Environments and NIOSH 5040 (National Institute of Occupational Safety and Health. Artifacts were observed using the NIOSH temperature program and identified as interactions between carbon and dust deposited on the filter matrix at high temperature (T>550ºC under the pure helium step of the analysis. During the MINOS campaign, Black Carbon (BC and Organic Carbon (OC mass concentrations were on average respectively 1.19±0.56 and 3.62±1.08 mgC/m3 for the IMPROVE temperature program, and 1.09±0.36 and 3.75±1.24 mgC/m3 for the thermal method. Though these values compare well on average and the agreement between the Total Carbon (TC measurements sample to sample was excellent (slope=1.00, r2=0.93, n=56, important discrepancies were observed in determining BC concentrations from these two methods (average error of 33±22%. BC from the IMPROVE temperature program compared well with non-sea-salt potassium (nss-K pointing out an optical sensitivity to biomass burning. On the other hand, BC from the thermal method showed a better agreement with non-sea-salt sulfate (nss-SO4, considered as a tracer for fossil fuel combustion during the MINOS campaign. The coupling between

  17. Assessment of carbonaceous aerosols in Shanghai, China – Part 1: long-term evolution, seasonal variations, and meteorological effects

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    Y. Chang

    2017-08-01

    Full Text Available Carbonaceous aerosols are major chemical components of fine particulate matter (PM2. 5 with major impacts on air quality, climate change, and human health. Gateway to fast-rising China and home of over twenty million people, Shanghai throbs as the nation's largest mega city and the biggest industrial hub. From July 2010 to December 2014, hourly mass concentrations of ambient organic carbon (OC and elemental carbon (EC in the PM2. 5 fraction were quasi-continuously measured in Shanghai's urban center. The annual OC and EC concentrations (mean ±1σ in 2013 (8.9 ± 6.2 and 2.6 ± 2.1 µg m−3, n =  5547 and 2014 (7.8 ± 4.6 and 2.1 ± 1.6 µg m−3, n =  6914 were higher than those of 2011 (6.3 ± 4.2 and 2.4 ± 1.8 µg m−3, n =  8039 and 2012 (5.7 ± 3.8 and 2.0 ± 1.6 µg m−3, n =  4459. We integrated the results from historical field measurements (1999–2012 and satellite observations (2003–2013, concluding that carbonaceous aerosol pollution in Shanghai has gradually reduced since 2006. In terms of monthly variations, average OC and EC concentrations ranged from 4.0 to 15.5 and from 1.4 to 4.7 µg m−3, accounting for 13.2–24.6 and 3.9–6.6 % of the seasonal PM2. 5 mass (38.8–94.1 µg m−3, respectively. The concentrations of EC (2.4, 2.0, 2.2, and 3.0 µg m−3 in spring, summer, fall, and winter, respectively showed little seasonal variation (except in winter and weekend–weekday dependence, indicating EC is a relatively stable constituent of PM2. 5 in the Shanghai urban atmosphere. In contrast to OC (7.3, 6.8, 6.7, and 8.1 µg m−3 in spring, summer, fall, and winter, respectively, EC showed marked diurnal cycles and correlated strongly with CO across all seasons, confirming vehicular emissions as the dominant source of EC at the targeted site. Our data also reveal that both OC and EC showed concentration gradients as a

  18. Thermal characteristics and mass absorption efficiency of carbonaceous aerosol measured during a post-harvest burning period

    Science.gov (United States)

    Batmunkh, T.; Kim, Y. J.; Cayetano, M. G.; Lee, K.; Kim, K.; Park, K.

    2012-12-01

    In order to better understand the characteristics of carbonaceous aerosol time-resolved OC, EC, and BC were measured by a Sunset OC/EC analyzer and an Aethalometer, respectively, during a post-harvest burning period from November 22 to December 20, 2011 at a sub-urban site in Gwangju, Korea. OC and EC were analyzed by the thermal-optical transmittance (TOT) method with NIOSH temperature protocol. The spectral light absorption coefficient (babs) was determined based on the Aethalometer data. Overall average OC and EC concentrations were found to be 5.0±2.4 ugC/ m3 and 1.5±0.9 ugC/ m3, respectively for the sampling period. On average, babs at seven Aethalometer wavelengths was found to be 38.4±27.8 Mm-1, 24.3±17.8 Mm-1, 20.8±15.4 Mm-1, 17.9±13.3 Mm-1, 14.9±11.1 Mm-1, 9.9±7.4 Mm-1, and 8.8±6.6 Mm-1 at 370 nm, 470 nm, 520 nm, 590 nm, 660 nm, 880 nm, and 950 nm, respectively. Clear diurnal variations with morning (7:00 AM~9:00 AM) and evening (7:00 PM~11:00 PM) peaks were observed for OC, EC, and babs mostly due to local burning activities. Based on the 4-day back-trajectory analyses conducted using the HYSPLIT model. Event cases were classified into four categories, based on the 4-day air mass back trajectories, as Clean(C), Stagnant(ST), Continental(CC), and Local Burning(LB) events. In order to better investigate the characteristics of atmospheric carbonaceous aerosol, thermal evolution patterns of carbonaceous aerosol measured by the Sunset analyzer were characterized as OC1, OC2, and EC, which were detected in temperature steps of 600 C, 840 C in an non-oxidizing atmosphere, and 870 C in an oxidizing atmosphere, respectively. High ratio of OC2/OC1; 1.39~1.41 was observed in the evening 9:00~11:00 PM due to local burning event. Concentration of OC2 was higher up to 1.4 times than that of OC1 for the LB cases, showing that higher molecular weight fraction of organic aerosol was dominant for the time. As expected, higher correlation was found between EC and

  19. Assessment of carbonaceous aerosols in Shanghai, China - Part 1: long-term evolution, seasonal variations, and meteorological effects

    Science.gov (United States)

    Chang, Yunhua; Deng, Congrui; Cao, Fang; Cao, Chang; Zou, Zhong; Liu, Shoudong; Lee, Xuhui; Li, Jun; Zhang, Gan; Zhang, Yanlin

    2017-08-01

    Carbonaceous aerosols are major chemical components of fine particulate matter (PM2. 5) with major impacts on air quality, climate change, and human health. Gateway to fast-rising China and home of over twenty million people, Shanghai throbs as the nation's largest mega city and the biggest industrial hub. From July 2010 to December 2014, hourly mass concentrations of ambient organic carbon (OC) and elemental carbon (EC) in the PM2. 5 fraction were quasi-continuously measured in Shanghai's urban center. The annual OC and EC concentrations (mean ±1σ) in 2013 (8.9 ± 6.2 and 2.6 ± 2.1 µg m-3, n = 5547) and 2014 (7.8 ± 4.6 and 2.1 ± 1.6 µg m-3, n = 6914) were higher than those of 2011 (6.3 ± 4.2 and 2.4 ± 1.8 µg m-3, n = 8039) and 2012 (5.7 ± 3.8 and 2.0 ± 1.6 µg m-3, n = 4459). We integrated the results from historical field measurements (1999-2012) and satellite observations (2003-2013), concluding that carbonaceous aerosol pollution in Shanghai has gradually reduced since 2006. In terms of monthly variations, average OC and EC concentrations ranged from 4.0 to 15.5 and from 1.4 to 4.7 µg m-3, accounting for 13.2-24.6 and 3.9-6.6 % of the seasonal PM2. 5 mass (38.8-94.1 µg m-3), respectively. The concentrations of EC (2.4, 2.0, 2.2, and 3.0 µg m-3 in spring, summer, fall, and winter, respectively) showed little seasonal variation (except in winter) and weekend-weekday dependence, indicating EC is a relatively stable constituent of PM2. 5 in the Shanghai urban atmosphere. In contrast to OC (7.3, 6.8, 6.7, and 8.1 µg m-3 in spring, summer, fall, and winter, respectively), EC showed marked diurnal cycles and correlated strongly with CO across all seasons, confirming vehicular emissions as the dominant source of EC at the targeted site. Our data also reveal that both OC and EC showed concentration gradients as a function of wind direction (WD) and wind speed (WS), generally with higher values associated with winds from the southwest, west, and northwest

  20. 21 CFR 73.3112 - C.I. Vat Orange 1.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false C.I. Vat Orange 1. 73.3112 Section 73.3112 Food... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3112 C.I. Vat Orange 1. (a) Identity. The color additive is C.I. Vat Orange 1, Colour Index No. 59105. (b) Uses and restrictions. (1) The...

  1. Spatial and spectral resolution of carbonaceous material from hematite (α-Fe2O3) using multivariate curve resolution-alternating least squares (MCR-ALS) with Raman microspectroscopic mapping: implications for the search for life on Mars.

    Science.gov (United States)

    Smith, Joseph P; Smith, Frank C; Booksh, Karl S

    2017-08-21

    The search for evidence of extant or past life on Mars is a primary objective of both the upcoming Mars 2020 rover (NASA) and ExoMars 2020 rover (ESA/Roscosmos) missions. This search will involve the detection and identification of organic molecules and/or carbonaceous material within the Martian surface environment. For the first time on a mission to Mars, the scientific payload for each rover will include a Raman spectrometer, an instrument well-suited for this search. Hematite (α-Fe 2 O 3 ) is a widespread mineral on the Martian surface. The 2LO Raman band of hematite and the Raman D-band of carbonaceous material show spectral overlap, leading to the potential misidentification of hematite as carbonaceous material. Here we report the ability to spatially and spectrally differentiate carbonaceous material from hematite using multivariate curve resolution-alternating least squares (MCR-ALS) applied to Raman microspectroscopic mapping under both 532 nm and 785 nm excitation. For this study, a sample comprised of hematite, carbonaceous material, and substrate-adhesive epoxy in spatially distinct domains was constructed. Principal component analysis (PCA) reveals that both 532 nm and 785 nm excitation produce representative three-phase systems of hematite, carbonaceous material, and substrate-adhesive epoxy in the analyzed sample. MCR-ALS with Raman microspectroscopic mapping using both 532 nm and 785 nm excitation was able to resolve hematite, carbonaceous material, and substrate-adhesive epoxy by generating spatially-resolved chemical maps and corresponding Raman spectra of these spatially distinct chemical species. Moreover, MCR-ALS applied to the combinatorial data sets of 532 nm and 785 nm excitation, which contain hematite and carbonaceous material within the same locations, was able to resolve hematite, carbonaceous material, and substrate-adhesive epoxy. Using multivariate analysis with Raman microspectroscopic mapping, 785 nm excitation more effectively

  2. Notas Para a Elucidação do Conceito de "Ciência"

    OpenAIRE

    Silva, Eduardo

    2011-01-01

    O presente escrito ("Notas para a Elucidação do Conceito de 'Ciência'") visa, como o seu próprio título indica, definir e elucidar o conceito de 'Ciência', bem como pôr em evidência quais são as relações conceptuais que subsistem entre a ciência e a filosofia e a própria ciência e a cultura (entendida esta sobretudo no sentido de 'mundividência').

  3. Uma visão comparada do ensino em ciência, tecnologia e sociedade na escola e em um museu de ciência

    Directory of Open Access Journals (Sweden)

    Guaracira Gouvêa

    2001-01-01

    Full Text Available Este trabalho apresenta a análise das narrativas de crianças e professores que se desenvolvem na sala de aula e em um museu de ciências, em situações de ensino-aprendizagem formal e não-formal. A pesquisa tratou das relações entre ensino formal (escola e não-formal (museu, focalizando indícios e práticas que envolvem, de um lado, o movimento CTS e, de outro, processos de alfabetização científica e tecnológica no ensino de ciências. Nas considerações finais, destacamos as contribuições da investigação para a melhoria do ensino de ciências.

  4. Quantitative determination of carbonaceous particle mixing state in Paris using single-particle mass spectrometer and aerosol mass spectrometer measurements

    Directory of Open Access Journals (Sweden)

    R. M. Healy

    2013-09-01

    Full Text Available Single-particle mixing state information can be a powerful tool for assessing the relative impact of local and regional sources of ambient particulate matter in urban environments. However, quantitative mixing state data are challenging to obtain using single-particle mass spectrometers. In this study, the quantitative chemical composition of carbonaceous single particles has been determined using an aerosol time-of-flight mass spectrometer (ATOFMS as part of the MEGAPOLI 2010 winter campaign in Paris, France. Relative peak areas of marker ions for elemental carbon (EC, organic aerosol (OA, ammonium, nitrate, sulfate and potassium were compared with concurrent measurements from an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, a thermal–optical OCEC analyser and a particle into liquid sampler coupled with ion chromatography (PILS-IC. ATOFMS-derived estimated mass concentrations reproduced the variability of these species well (R2 = 0.67–0.78, and 10 discrete mixing states for carbonaceous particles were identified and quantified. The chemical mixing state of HR-ToF-AMS organic aerosol factors, resolved using positive matrix factorisation, was also investigated through comparison with the ATOFMS dataset. The results indicate that hydrocarbon-like OA (HOA detected in Paris is associated with two EC-rich mixing states which differ in their relative sulfate content, while fresh biomass burning OA (BBOA is associated with two mixing states which differ significantly in their OA / EC ratios. Aged biomass burning OA (OOA2-BBOA was found to be significantly internally mixed with nitrate, while secondary, oxidised OA (OOA was associated with five particle mixing states, each exhibiting different relative secondary inorganic ion content. Externally mixed secondary organic aerosol was not observed. These findings demonstrate the range of primary and secondary organic aerosol mixing states in Paris. Examination of the

  5. Construction of a 1° × 1° fossil fuel emission data set for carbonaceous aerosol and implementation and radiative impact in the ECHAM4 model

    Science.gov (United States)

    Cooke, W. F.; Liousse, C.; Cachier, H.; Feichter, J.

    1999-09-01

    Global-scale emissions of carbonaceous aerosol from fossil fuel usage have been calculated with a resolution of 1° × 1°. Emission factors for black and organic carbon have been gathered from the literature and applied to domestic, transport, and industrial combustion of various fuel types. In addition, allowance has been made for the level of development when calculating emissions from a country. Emissions have been calculated for 185 countries for the domestic, industrial, and transport sectors using a fuel usage database published by the United Nations [1993]. Some inconsistencies were found for a small number of countries with regard to the distribution of fuel usage between the industrial and domestic sectors. Care has been taken to correct for this using data from the fuel use database for the period 1970-1990. Emissions based on total particulate matter (TPM) and submicron emission factors have been calculated. Global emissions for 1984 of black carbon total 6.4 TgC yr-1 and organic carbon emissions of 10.1 TgC yr-1 were found using bulk aerosol emission factors, while global black carbon emissions of 5.1 TgC yr-1 and organic carbon emissions of 7.0 TgC yr-1 were found using submicron emission factors. Use of the database is quite flexible and can be easily updated as emission factor data are updated. There is at least a factor of 2 uncertainty in the derived emissions due to the lack of exactly appropriate emission data. The emission fields have been introduced into the ECHAM4 atmospheric general circulation model and run for 5 model years. Monthly mean model results are compared to measurements in regions influenced by anthropogenic fossil fuel emissions. The resultant aerosol fields have been used to calculate the instantaneous solar radiative forcing at the top of the troposphere due to an external mixture of fossil fuel derived black carbon and organic carbon aerosol. Column burdens of 0.143 mgBC m-2 and 0.170 mgOC m-2 were calculated. Because of

  6. Source apportionment of carbonaceous chemical species to fossil fuel combustion, biomass burning and biogenic emissions by a coupled radiocarbon-levoglucosan marker method

    Science.gov (United States)

    Salma, Imre; Németh, Zoltán; Weidinger, Tamás; Maenhaut, Willy; Claeys, Magda; Molnár, Mihály; Major, István; Ajtai, Tibor; Utry, Noémi; Bozóki, Zoltán

    2017-11-01

    An intensive aerosol measurement and sample collection campaign was conducted in central Budapest in a mild winter for 2 weeks. The online instruments included an FDMS-TEOM, RT-OC/EC analyser, DMPS, gas pollutant analysers and meteorological sensors. The aerosol samples were collected on quartz fibre filters by a low-volume sampler using the tandem filter method. Elemental carbon (EC), organic carbon (OC), levoglucosan, mannosan, galactosan, arabitol and mannitol were determined, and radiocarbon analysis was performed on the aerosol samples. Median atmospheric concentrations of EC, OC and PM2.5 mass were 0.97, 4.9 and 25 µg m-3, respectively. The EC and organic matter (1.6 × OC) accounted for 4.8 and 37 %, respectively, of the PM2.5 mass. Fossil fuel (FF) combustion represented 36 % of the total carbon (TC = EC + OC) in the PM2.5 size fraction. Biomass burning (BB) was a major source (40 %) for the OC in the PM2.5 size fraction, and a substantial source (11 %) for the PM10 mass. We propose and apply here a novel, straightforward, coupled radiocarbon-levoglucosan marker method for source apportionment of the major carbonaceous chemical species. The contributions of EC and OC from FF combustion (ECFF and OCFF) to the TC were 11.0 and 25 %, respectively, EC and OC from BB (ECBB and OCBB) were responsible for 5.8 and 34 %, respectively, of the TC, while the OC from biogenic sources (OCBIO) made up 24 % of the TC. The overall relative uncertainty of the OCBIO and OCBB contributions was assessed to be up to 30 %, while the relative uncertainty for the other apportioned species is expected to be below 20 %. Evaluation of the apportioned atmospheric concentrations revealed some of their important properties and relationships among them. ECFF and OCFF were associated with different FF combustion sources. Most ECFF was emitted by vehicular road traffic, while the contribution of non-vehicular sources such as domestic and industrial heating or cooking using gas, oil or coal

  7. Characterization, Long-Range Transport and Source Identification of Carbonaceous Aerosols during Spring and Autumn Periods at a High Mountain Site in South China

    Directory of Open Access Journals (Sweden)

    Hong-yan Jia

    2016-09-01

    Full Text Available PM10 (particulate matter samples were collected at Mount Lu, a high elevation mountain site in south China (August and September of 2011; and March, April and May of 2012. Eight carbonaceous fractions of particles were analyzed to characterize the possible carbonaceous emission sources. During the sampling events, daily average concentrations of PM10 at Mount Lu were 97.87 μg/m3 and 73.40 μg/m3 in spring and autumn, respectively. The observed mean organic carbon (OC and element carbon (EC concentrations during spring in PM10 were 10.58 μg/m3 and 2.58 μg/m3, respectively, and those in autumn were 6.89 μg/m3 and 2.40 μg/m3, respectively. Secondary organic carbon concentration was 4.77 μg/m3 and 2.93 μg/m3 on average, accounting for 28.0% and 31.0% of the total OC in spring and autumn, respectively. Relationships between carbonaceous species and results of principal component analysis showed that there were multiple sources contributing to the carbonaceous aerosols at the observation site. Through back trajectory analysis, it was found that air masses in autumn were mainly transported from the south of China, and these have the highest OC but lowest EC concentrations. Air masses in spring transported from northwest China bring 7.77 μg/m3 OC and 2.28 μg/m3 EC to the site, with lower levels coming from other sites. These air mass sources were featured by the effective carbon ratio (ECR.

  8. Analysis of the saturated hydrocarbon in coal, carbonaceous mudstone and oils from the lower Jurassic coal measures in the Turpan Basin by GC/MS

    International Nuclear Information System (INIS)

    Fang Xuan; Meng Qianxiang; Sun Minzhuo; Du Li; Ding Wanren

    2005-01-01

    Saturated hydrocarbon of coal, carbonaceous mudstone and oils from the Lower Jurassic coal measures in the Turpan basin were studied, and biomarker characteristics and coal thermal maturity analyzed to draw the following conclusions. T here are many similar biomarker characteristics between oil from middle-lower Jurassic of Turpan Basin and coal and carbonaceous mudstone in the same strata. They all contain specific r-lupane, I-norbietane, C 24 -tetracyclic and high content of C 29 -steranes. These characteristics suggest that they have similar matter source of the organic matter derived from matter with abundant high plants. Meanwhile, biomarkers often used to indicate depositional environments characterized by high Pr/Ph ratio, little or no gammacerane and high abundance dibenzofurans, such biomarker distributions are indicative of suboxic and freshwater environment. Although coal and carbonaceous mudstone remain in lower thermal maturity (Ro=0.47-0.53), but C 29 -ββ/(αα+ββ) sterane ratio (0.294-0.489) and bezohopane are detected. Because these ferture are related to bacterial activity, bacterial degradation of organic matter maybe take an important role in coal-derived oil. (authors)

  9. A New Method of Absorption-Phase Nanotomography for 3D Observation of Mineral-Organic-Water Textiles and its Application to Pristine Carbonaceous Chondrites

    Science.gov (United States)

    Tsuchiyama, A.; Nakato, A.; Matsuno, J.; Sugimoto, M.; Uesugi, K.; Takeuchi, A.; Nakano, T.; Vaccaro, E.; Russel, S.; Nakamura-Messenger, K.; hide

    2017-01-01

    Pristine carbonaceous chondrites contain fine-grained matrix, which is composed largely of amorphous silicates, sub-micron silicate and sulfide crystals, and organic materials. They are regarded as primitive dust in the early Solar System that have suffered minimal alteration in their parent bodies. The matrix generally has different lithologies; some of them are unaltered but some are more or less aqueously altered. Their textures have been examined in 2D usually by FE-SEM/EDS, TEM/EDS, nano-SIMS and micro-XRD. Observation of their complex fine textures, such as spatial relation between different lithologies in 3D, is important for understanding aggregation and alteration processes. Synchrotron radiation (SR)-based X-ray tomography reveals 3D structures nondestructively with high spatial resolution of approximately greater than 100 nm. We have developed a new technique using absorption contrasts called "dual-energy tomography" (DET) to obtain 3D distribution of minerals at SPring-8, SR facility in Japan, and applied successfully to Itokawa particles. Phase and absorption contrast images can be simultaneously obtained in 3D by using "scanning-imaging x-ray microscopy" (SIXM) at SPring-8, which can discriminate between void, water and organic materials. We applied this technique combined with FIB micro-sampling to carbonaceous chondrites to search for primitive liquid water. In this study, we combined the DET and SIXM to obtain three dimensional submicron-scale association between minerals, organic materials and water and applied this to pristine carbonaceous chondrites.

  10. Long-term (2001-2012) trends of carbonaceous aerosols from a remote island in the western North Pacific: an outflow region of Asian pollutants

    Science.gov (United States)

    Boreddy, Suresh K. R.; Mozammel Haque, M.; Kawamura, Kimitaka

    2018-01-01

    The present study reports on long-term trends of carbonaceous aerosols in total suspended particulate (TSP) samples collected at Chichijima in the western North Pacific during 2001-2012. Seasonal variations of elemental carbon (EC), organic carbon (OC), and water-soluble organic carbon (WSOC) concentrations showed maxima in winter to spring and minima in summer. These seasonal differences in the concentrations of carbonaceous aerosols were associated with the outflows of polluted air masses from East Asia, which are clearly distinguishable from pristine air masses from the central Pacific. The higher concentrations of carbonaceous aerosols during winter to spring are associated with long-range atmospheric transport of East Asian continental polluted air masses, whereas lower concentrations may be due to pristine air masses from the central Pacific in summer. The annual trends of OC / EC (+0.46 % yr-1), WSOC (+0.18 % yr-1) and WSOC / OC (+0.08 % yr-1) showed significant (p biogenic emissions are also important over the western North Pacific as inferred from a significant increase (+0.14 % yr-1) in the concentrations of methanesulfonate (MSA-, a tracer for biogenic sources). This point was further supported by a moderate correlation (r = 0.40) between WSOC and MSA-. We also found a significant increase in OC / TC (total carbon) and WSOC / TC ratios, further suggesting that photochemical formation of WSOC and its contributions to SOAs have increased over the western North Pacific during 2001-2012 via long-range atmospheric transport from East Asia.

  11. Da possibilidade de uma Teoria Pura da Ciência da Informação: reflexões iniciais entre a Ciência da Informação e a Ciência do Direito

    Directory of Open Access Journals (Sweden)

    Max Cirino de Mattos

    Full Text Available O artigo discute a fragilidade epistemológica da Ciência da Informação, a partir da adoção de um termo polissêmico, como objeto científico, e a similaridade dessa situação com o contexto da criação da Teoria Pura do Direito de Hans Kelsen. Após a apresentação de algumas definições sobre o objeto da Ciência da Informação, discutem-se alguns reflexos relacionados à identidade científica e à fundamentação teórica derivadas de um objeto polissêmico. Apresenta-se uma breve introdução à Teoria Pura do Direito e algumas reflexões sobre a possibilidade de uma Teoria Pura da Ciência da Informação.

  12. The MMN as a viable and objective marker of auditory development in CI users

    DEFF Research Database (Denmark)

    Näätänen, Risto; Petersen, Bjørn; Torppa, Ritva

    2017-01-01

    In the present article, we review the studies on the use of the mismatch negativity (MMN) as a tool for an objective assessment of cochlear-implant (CI) functioning after its implantation and as a function of time of CI use. The MMN indexes discrimination of different sound stimuli with a precision...

  13. Four routes to continuous improvement. An empirical typology of CI implementation processes

    NARCIS (Netherlands)

    Rijnders, Sander

    2002-01-01

    Continuous Improvement (CI) is a well-established concept that many companies adopt in some form. It is often suggested that CI's main problem lies in its implementation. Most of the literature is prescriptive or focuses on success and failure aspects. Until now, however, little is known about the

  14. Dyskusja wokół celu sprawozdawczości finansowej opartej na MSSF

    Directory of Open Access Journals (Sweden)

    Edyta Łazarowicz

    2016-07-01

    Full Text Available Celem artykułu jest analiza i ocena propozycji zmian odnośnie do celu sprawozdawczości finansowej opartej na Międzynarodowych Standardach Sprawozdawczości Finansowej (MSSF przedstawionych w komentarzach do projektu Założeń koncepcyjnych sprawozdawczości finansowej (2015. Większość respondentów uważa, że w celu sprawozdawczości finansowej należy zwiększyć znaczenie dostarczania informacji o wypełnieniu funkcji powierniczej przez kierownictwo (stewardship. Ponadto proponują oni przedstawienie definicji stewardship w Założeniach koncepcyjnych oraz wskazanie konsekwencji zmiany celu sprawozdawczości finansowej dla przyszłego tworzenia standardów i dla sporządzania sprawozdań finansowych. Z analizy komentarzy i przeglądu literatury wynika, że cel sprawozdawczości finansowej powinien być zmieniony. Sprawą dyskusyjną pozostaje jednak, czy stewardship powinien być odrębnym celem. Niestety, jest za mało badań dotyczących relacji pomiędzy stewardship i użytecznością decyzyjną. Ich wyniki mogłyby wskazać twórcom standardów rachunkowości potencjalne kompromisy i konflikty między nimi.

  15. CiF-CK: An Architecture for Social NPCs in Commercial Games

    NARCIS (Netherlands)

    Guimaraes, Manuel; Santos, Pedro A.; Jhala, Arnav

    2018-01-01

    We present and describe CiF-CK — a social agent architecture that models reasoning about persistent social interactions to improve narrative engagement and play experience for human interactors. The architecture is inspired by McCoy et al’s Comme il-Faut (CiF) architecture that represented

  16. A Tale of CI Build Failures : An Open Source and a Financial Organization Perspective

    NARCIS (Netherlands)

    Vassallo, Carmine; Schermann, Gerald; Zampetti, Fiorelli; Romano, Daniele; Leitner, Philipp; Zaidman, A.E.; Di Penta, Massimiliano; Panichella, Sebastiano

    2017-01-01

    Continuous Integration (CI) and Continuous Delivery (CD) are widespread in both industrial and open-source software (OSS) projects. Recent research characterized build failures in CI and identified factors potentially correlated to them. However, most observations and findings of previous work are

  17. The Contradiction Index (CI): A New Metric Combining System Complexity and Robustness for Early Design Stages

    DEFF Research Database (Denmark)

    Göhler, Simon Moritz; Howard, Thomas J.

    2015-01-01

    design iterations, a positive correlation was found. Furthermore, when correlating the CI against the number of challenging tolerances statistical significance was found (p=0.01). It is envisaged that the CI will be a powerful approach to estimate and compare development difficulty and to guide...... development and design improvements....

  18. CO2 sorption on surface-modified carbonaceous support: Probing the influence of the carbon black microporosity and surface polarity

    Science.gov (United States)

    Gargiulo, Valentina; Alfè, Michela; Ammendola, Paola; Raganati, Federica; Chirone, Riccardo

    2016-01-01

    The use of solid sorbents is a convenient option in post-combustion CO2 capture strategies. Sorbents selection is a key point because the materials are required to be both low-cost and versatile in typical post-combustion conditions in order to guarantee an economically advantageous overall process. This work compares strategies to tailor the chemico-physical features of carbon black (CB) by surface-modification and/or coating with a CO2-sorbent phase. The influence of the CB microporosity, enhanced by chemical/thermal treatments, is also taken into account. Three CB surface modifications are performed and compared: (i) oxidation and functionalization with amino-groups, (ii) coating with iron oxides and (iii) impregnation with an ionic liquid (IL). The CO2 capture performance is evaluated on the basis of the breakthrough curves measured at atmospheric pressure and room temperature in a lab-scale fixed bed micro-reactor. Most of tested solids adsorb a CO2 amount significantly higher than a 13X zeolite and DARCO FGD (Norit) activated carbon (up to 4 times more in the best case). The sorbents bearing basic functionalities (amino-groups and IL) exhibit the highest CO2 sorption capacity. The use of a microporous carbonaceous support limits the accessibility of CO2 toward the adsorbing phase (IL or FM) lowering the number of accessible binding sites for CO2.

  19. N- and O-doped hollow carbonaceous spheres with hierarchical porous structure for potential application in high-performance capacitance

    Science.gov (United States)

    Chen, Ze; Cao, Rui; Ge, Yuanhang; Tu, Yingfeng; Xia, Yu; Yang, Xiaoming

    2017-09-01

    Hollow carbonaceous spheres (HCSs) have been extensively investigated due to their valuable potentials in the applications of energy storage devices such as solar cells, fuel cells, and supercapacitors. It is highly desirable to develop abundant pore structures and introduce heteroatoms in the resultant HCSs to improve capacitance of the devices. Herein, N-, and O-doped HCSs with macro/micro/mesoporous structures are successfully prepared by one-step carbonization of polypyrrole coated polystyrene nanoparticles followed by chemical activation with KOH. The huge specific surface area (up to 935 m2 g-1) and hierarchical porous structures can effectively facilitate the transportation and exchange of ions and electrons. Besides, high heteroatom content (∼30%) are believed to provide pseudocapacitance contributed from the redox faradic reactions of these electrochemically active functional groups. The as-prepared activated HCSs possess a high capacitance of 535 F g-1 at a current density of 0.2 A g-1, and maintains 55% of the highest capacitance even at a current density of 10 A g-1. The newly prepared HCSs thus show great potential as the electrode materials of supercapacitors.

  20. Measurements of non-volatile aerosols with a VTDMA and their correlations with carbonaceous aerosols in Guangzhou, China

    Science.gov (United States)

    Cheung, Heidi H. Y.; Tan, Haobo; Xu, Hanbing; Li, Fei; Wu, Cheng; Yu, Jian Z.; Chan, Chak K.

    2016-07-01

    Simultaneous measurements of aerosol volatility and carbonaceous matters were conducted at a suburban site in Guangzhou, China, in February and March 2014 using a volatility tandem differential mobility analyzer (VTDMA) and an organic carbon/elemental carbon (OC / EC) analyzer. Low volatility (LV) particles, with a volatility shrink factor (VSF) at 300 °C exceeding 0.9, contributed 5 % of number concentrations of the 40 nm particles and 11-15 % of the 80-300 nm particles. They were composed of non-volatile material externally mixed with volatile material, and therefore did not evaporate significantly at 300 °C. Non-volatile material mixed internally with the volatile material was referred to as medium volatility (MV, 0.4 transported at low altitudes (below 1500 m) for over 40 h before arrival. Further comparison with the diurnal variations in the mass fractions of EC and the non-volatile OC in PM2.5 suggests that the non-volatile residuals may be related to both EC and non-volatile OC in the afternoon, during which the concentration of aged organics increased. A closure analysis of the total mass of LV and MV residuals and the mass of EC or the sum of EC and non-volatile OC was conducted. It suggests that non-volatile OC, in addition to EC, was one of the components of the non-volatile residuals measured by the VTDMA in this study.

  1. Comparative study of adsorptive role of carbonaceous materials in removal of UV-active impurities of paclitaxel extracts.

    Science.gov (United States)

    Nasiri, Jaber; Motamedi, Elaheh; Reza Naghavi, Mohammad

    2015-12-01

    Graphite oxide (GO) and reduced graphene oxide (rGO) nanosheets were synthesized with a low-cost manufacturing method. The morphology and structures of the synthesized samples were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), Fourier-transform infrared (FTIR) and Raman spectroscopy. The efficiencies of GO and rGO as novel candidate adsorbents in the pre-purification of paclitaxel were compared and contrasted with those of commercial graphite (Gt), graphene (G) and multi-wall carbon nanotube (MWCNT). According to UV-vis and HPLC analyses, rGO was evaluated as the best absorbent for the removal of impurities in pre-purification of paclitaxel from plant cell cultures. In contrast, the GO had the poorest proficiency for paclitaxel pre-purification in comparison with the other carbonaceous adsorbents. This is attributed to the existence of many localized defects in the π-structure of GO that is related to weakness of π-π stacking interactions between crude extract impurities and GO.

  2. Comparative study of adsorptive role of carbonaceous materials in removal of UV-active impurities of paclitaxel extracts

    Directory of Open Access Journals (Sweden)

    Jaber Nasiri

    2015-12-01

    Full Text Available Graphite oxide (GO and reduced graphene oxide (rGO nanosheets were synthesized with a low-cost manufacturing method. The morphology and structures of the synthesized samples were studied using X-ray diffraction (XRD, atomic force microscopy (AFM, Fourier-transform infrared (FTIR and Raman spectroscopy. The efficiencies of GO and rGO as novel candidate adsorbents in the pre-purification of paclitaxel were compared and contrasted with those of commercial graphite (Gt, graphene (G and multi-wall carbon nanotube (MWCNT. According to UV–vis and HPLC analyses, rGO was evaluated as the best absorbent for the removal of impurities in pre-purification of paclitaxel from plant cell cultures. In contrast, the GO had the poorest proficiency for paclitaxel pre-purification in comparison with the other carbonaceous adsorbents. This is attributed to the existence of many localized defects in the π-structure of GO that is related to weakness of π–π stacking interactions between crude extract impurities and GO.

  3. Synthesis of Au nanoparticles at the surface and embedded in carbonaceous matrix by 150 keV Ar ion irradiation

    International Nuclear Information System (INIS)

    Prakash, Jai; Tripathi, Jalaj; Tripathi, A; Kumar, P; Asokan, K; Avasthi, D K; Rigato, V; Pivin, J C; Chae, Keun Hwa; Gautam, Sanjeev

    2011-01-01

    We report on synthesis of spherical Au nanoparticles at the surface and embedded in carbonaceous matrix by 150 keV Ar ion irradiation of thin Au film on polyethyleneterepthlate (PET). The pristine and irradiated samples are characterized by Rutherford backscattering spectrometry (RBS), atomic force microscopy, scanning electron microscopy and transmission electron microscopy (TEM) techniques. RBS spectra reveal the sputtering of Au film and interface mixing, increasing with increasing fluence. Surface morphology shows that at the fluence of 5 x 10 15 ions cm -2 , dewetting of thin Au film begins and partially connected nanostructures are formed whereas, at the higher fluence of 5 x 10 16 ions cm -2 , isolated spherical Au nanoparticles (45 ± 20 nm) are formed at the surface. Cross-sectional TEM observations also evidence the Au nanoparticles at the surface and mixed metal-polymer region indicating the formation of nanocomposites with small Au nanoparticles. The results are explained by the crater formation, sputtering followed by dewetting of the thin Au film and interdiffusion at the interface, through molten zones due to thermal spike induced by Ar ions.

  4. Artificial neural network modeling in competitive adsorption of phenol and resorcinol from water environment using some carbonaceous adsorbents.

    Science.gov (United States)

    Aghav, R M; Kumar, Sunil; Mukherjee, S N

    2011-04-15

    This paper illustrates the application of artificial neural network (ANN) for prediction of performances in competitive adsorption of phenol and resorcinol from aqueous solution by conventional and low cost carbonaceous adsorbent materials, such as activated carbon (AC), wood charcoal (WC) and rice husk ash (RHA). The three layer's feed forward neural network with back propagation algorithm in MATLAB environment was used for estimation of removal efficiencies of phenol and resorcinol in bi-solute water environment based on 29 sets of laboratory batch study results. The input parameters used for training of the neural network include amount of adsorbent (g/L), initial concentrations of phenol (mg/L) and resorcinol (mg/L), contact time (h), and pH. The removal efficiencies of phenol and resorcinol were considered as an output of the neural network. The performances of the developed ANN models were also measured using statistical parameters, such as mean error, mean square error, root mean square error, and linear regression. The comparison of the removal efficiencies of pollutants using ANN model and experimental results showed that ANN modeling in competitive adsorption of phenolic compounds reasonably corroborated with the experimental results. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. Carbonaceous composition changes of heavy-duty diesel engine particles in relation to biodiesels, aftertreatments and engine loads.

    Science.gov (United States)

    Cheng, Man-Ting; Chen, Hsun-Jung; Young, Li-Hao; Yang, Hsi-Hsien; Tsai, Ying I; Wang, Lin-Chi; Lu, Jau-Huai; Chen, Chung-Bang

    2015-10-30

    Three biodiesels and two aftertreatments were tested on a heavy-duty diesel engine under the US FTP transient cycle and additional four steady engine loads. The objective was to examine their effects on the gaseous and particulate emissions, with emphasis given to the organic and elemental carbon (OC and EC) in the total particulate matter. Negligible differences were observed between the low-sulfur (B1S50) and ultralow-sulfur (B1S10) biodiesels, whereas small reductions of OC were identified with the 10% biodiesel blend (B10). The use of diesel oxidation catalyst (DOC1) showed moderate reductions of EC and particularly OC, resulting in the OC/EC ratio well below unity. The use of DOC plus diesel particulate filter (DOC2+DPF) yielded substantial reductions of OC and particularly EC, resulting in the OC/EC ratio well above unity. The OC/EC ratios were substantially above unity at idle and low load, whereas below unity at medium and high load. The above changes in particulate OC and EC are discussed with respect to the fuel content, pollutant removal mechanisms and engine combustion conditions. Overall, the present study shows that the carbonaceous composition of PM could change drastically with engine load and aftertreatments, and to a lesser extent with the biodiesels under study. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Effect of Fuel Injection Strategy on the Carbonaceous Structure Formation and Nanoparticle Emission in a DISI Engine Fuelled with Butanol

    Directory of Open Access Journals (Sweden)

    Simona Silvia Merola

    2017-06-01

    Full Text Available Within the context of ever wider expansion of direct injection in spark ignition engines, this investigation was aimed at improved understanding of the correlation between fuel injection strategy and emission of nanoparticles. Measurements performed on a wall guided engine allowed identifying the mechanisms involved in the formation of carbonaceous structures during combustion and their evolution in the exhaust line. In-cylinder pressure was recorded in combination with cycle-resolved flame imaging, gaseous emissions and particle size distribution. This complete characterization was performed at three injection phasing settings, with butanol and commercial gasoline. Optical accessibility from below the combustion chamber allowed visualization of diffusive flames induced by fuel deposits; these localized phenomena were correlated to observed changes in engine performance and pollutant species. With gasoline fueling, minor modifications were observed with respect to combustion parameters, when varying the start of injection. The alcohol, on the other hand, featured marked sensitivity to the fuel delivery strategy. Even though the start of injection was varied in a relatively narrow crank angle range during the intake stroke, significant differences were recorded, especially in the values of particle emissions. This was correlated to the fuel jet-wall interactions; the analysis of diffusive flames, their location and size confirmed the importance of liquid film formation in direct injection engines, especially at medium and high load.

  7. Ciências Humanas e Sociais: ciências moles? A propósito do trabalho científico nesta contemporaneidade

    Directory of Open Access Journals (Sweden)

    Maria Adélia Aparecida de Souza

    2011-08-01

    Full Text Available Este ensaio busca atender uma velha e interminável discussão sobre uma questão que longe de ser científica é, sobretudo, política, qual seja a classificação das ciências. A Geografia tem oscilado nessas classificações: ora é uma ciência humana, social, ora é uma ciência da natureza. Este estímulo é o motivo principal da realização deste ensaio que, inspirado em uma interessante reflexão de Abraham Moles, prêmio Nobel de Matemática, quando sugere que reflitamos com seriedade científica e acadêmica sobre esse debate. Esse autor propõe corajosamente que as ciências humanas sejam elas sim consideradas “ci</