Insoluble Organic Fraction Research Articles

Trace and Rare Earth Element Partitioning in Organic Fractions of Mudstones during the Oil Formation

In order to investigate trace and rare earth element partitioning in organic fractions of mudstones, this study isolated organic fractions of mudstones, including insoluble organic fraction (kerogen), soluble organic fraction (extract), or expelled hydrocarbon (reservoir solid bitumen), and the isolated organic fractions and their corresponding whole rocks for trace and rare earth element compositions were measured. Analysis of trace and rare earth element compositions in organic fractions of lacustrine and marine mudstones revealed that mudstone kerogens were more enriched in rare earth elements (REE) and redox-sensitive trace elements (e.g., U, Mo, and Ni) relative to corresponding whole rocks. During the oil generation, middle rare earth elements (Sm-Ho), especially Eu, migrated from kerogen to extract more easily than the rest REE. The Eu was easily transferred to soluble hydrocarbon under the acidic and reducing environments formed by oil generation, resulting in the higher concentrations of Eu relative to its neighboring REE (Sm and Gd) and the pronounced positive Eu anomalies. Transition metal elements (e.g., Mo, V, Cr, Co, Ni, Cu, and Zn) also more easily released from kerogen than the rest elements, especially V and Ni. The enrichment and mobilization of trace elements in organic fractions of mudstones, such as Mo, U, V, Ni, and Ba, are closely related with their geochemical behaviors during the depositional and early digenetic processes, providing the potential information for predicting the distribution characteristics of trace elements in the expelled hydrocarbons of mudstones (e.g., crude oil and solid bitumen) and fingerprinting of oil to source.

Ablation Rates of Organic Compounds in Cosmic Dust and Resulting Changes in Mechanical Properties During Atmospheric Entry

AbstractA new experimental system is described for studying the pyrolysis of the refractory organic constituents in cosmic dust during atmospheric entry. The pyrolysis kinetics of meteoritic fragments (CM2 and CV3 carbonaceous chondrites, radius = 36–100 μm) were measured by mass spectrometric detection of CO2 and SO2 at temperatures between 625 and 1300 K, with most carbon being lost between 700 and 800 K. The complex time‐resolved kinetic behavior is consistent with two organic components—one significantly more refractory than the other, which probably correspond to the insoluble and soluble organic fractions, respectively. The measured temperature‐dependent pyrolysis rates were then incorporated into the Leeds Chemical Ablation Model, which demonstrates that organic pyrolysis should be detectable using a high performance/large aperture radar. Atomic force microscopy was used to show that although the residual meteoritic particles became more brittle after organic pyrolysis, they also became slightly harder, withstanding stresses that are at least three orders of magnitude higher than would be encountered during atmospheric entry. This suggests that most cosmic dust particles (radius <100 μm) will not fragment during entry into the atmosphere as a result of organic pyrolysis, although a subset of slow‐moving, low density particles mostly from Jupiter‐family comets could fragment.

Analytical pyrolysis and thermal analysis to chemically characterise bitumen from Italian geological deposits and Neolithic stone tools

The chemical study of bitumen from stone tools from Italian Neolithic sites was carried out using analytical pyrolysis-based techniques, EGA-MS (evolved gas analysis mass spectrometry) and DSPy-GC/MS (double shot pyrolysis-gas chromatography/mass spectrometry). The study was mainly aimed at demonstrating the suitability of analytical pyrolysis for studying archaeological bitumen and for obtaining information regarding its origin. EGA-MS was employed to obtain information on the thermal complexity, that is the set of thermal properties and behaviours, of the samples and on their thermal degradation areas and DSPy-GC/MS along with Principal Component Analysis (PCA) were tested for biomarker analysis to assess bitumen source in archaeological objects. Geological bituminous rocks from Central-Southern Italy were selected and used as reference materials to both optimize experimental parameters and to support data interpretation for archaeological samples. Geological samples were also preliminary characterised by thermogravimetric analysis coupled with FTIR spectroscopy (TG-FTIR) under nitrogen and by TG analysis under oxygen to quantify their relative content of organic and inorganic species.The combination of thermal analysis and analytical pyrolysis-based techniques allowed us to quantify the organic content of the bitumen samples and to obtain information on both soluble and insoluble organic fractions. In addition, the proposed approach highlighted the main degradative patterns and the main differences among samples coming from different geographical areas as well as differences between geological and archaeological bitumen. Finally, DSPy-GC/MS associated with PCA proved to be successful in assessing the bitumen source in archaeological objects by the detection of terpanes, distinctive biomarkers.

PM Reduction for Marine Diesel Engines with Electrostatic Cyclone Precipitator - Effect of Engine Types on Reducing PM and Onboard Test of 2-Stroke Main Propulsion Engines

In this study, the authors investigated particulate matter (PM) collection efficiency of an electrostatic-cyclone precipitator (ESP-cyclone) by conducting bench tests and onboard measurements of PM emissions with three diesel engines. A small sized high-speed 4-Stroke diesel was used for a bench test and two types of low-speed 2-Stroke marine diesels were utilized for another bench test and onboard PM measurements aboard a ship of 2,703 gross-tonnage. In order to study PM collection efficiency of the ESP-cyclone, PM concentrations in exhaust gas were measured upstream and downstream of the ESP-cyclone with a partial flow dilution tunnel system. Experimental results showed that the PM collection efficiency was as high as 60-80% with the ESP-cyclone collecting not only insoluble organic fraction (ISF), but also soluble organic fraction (SOF). The ESP-cyclone realizes stable PM reduction from the diesel engine on the actual ship.

Age Estimates on the Deposition of the Cave Ice Block in the Saarhalle Dachstein-Mammoth Cave (Mammuthöhle, Austria) based on 3H and 14C

ABSTRACTMeasurements of the radiocarbon (14C) and tritium (3H) activity in a 5.8-m-long ice core from the Saarhalle, Dachstein-Mammoth Cave allowed a substantial revision of previous opinions concerning the age of the ice block, and provide useful experience that may be applied to future 14C dating of cave ice deposits. The stepped combustion technique results in a remarkably older radiocarbon age for the 800°C than for the 400°C fractions of the carbonaceous matter from ice layer samples. The highest tritium activity (37.2±1.2 TU) can be linked to the period of anthropogenically increased tritium activity of atmospheric precipitation at the mid-1960s, providing a well-dated radiochemical reference horizon. Compared the 3H-based extrapolated ages of two shallow samples to the expected atmospheric signal an average 14C reservoir bias of ~1500 BP was obtained for the insoluble organic fraction combusted at 400°C. The conventional 14C age measured for the 400°C fraction of the deeper samples has been corrected with the average reservoir bias. The median calibrated age of the deepest analyzed sample of the ice profile is ~1830 cal BC and a linear extrapolation to the bottom ice layer gave 2590 cal BC, making the Saarhalle ice block among the oldest dated cave ice deposits known in the Alpine domain.

Abundance and 14C-based source assessment of carbonaceous materials in PM2.5 aerosols in Guangzhou, South China

In this study, the carbonaceous aerosols were separated into organic carbon (OC), water soluble OC (WSOC), water soluble humic-like substances (HULIS), water soluble non-HULIS, water insoluble OC (WINSOC), and soot carbon (SC). Then the abundance and 14 C content of carbon fractions were determined to assess the contribution of contemporary versus fossil sources. The results showed that the OC fraction is the major carbon fraction, the OC sub-fractions such as WSOC, HULIS, non-HULIS, and WINSOC accounted for 39.5%–66.7%, 24.8%–43.2%, 11.9%–23.5%, and 31.3%–55.2% of total carbon (TC), respectively. The 14 C data show that the contribution of contemporary carbon ( f c ) to TC is 38.3%–63.5%, all carbon fractions were mixtures of carbon derived from contemporary and fossil sources. The f c values of OC (38.8%–63.9%) more than that (25.7%–46.6%) of SC in the same sample, indicated OC generally contained more contemporary carbon than SC. The WSOC and HULIS had relatively higher f c levels than the corresponding WINSOC and the f c values of WINSOC all less than 45%, indicated that the insoluble organic fractions in PM 2.5 samples were dominated by fossil fuel related sources. These results suggested that the contemporary and fossil contributions for different carbon fractions are different. In addition, the seasonal and spatial variations of contemporary and fossil contributions to carbon fractions indicated that the PM 2.5 samples collected during summer at background site (Maofengshan, MFS) and winter at urban site (Wushan, WS) have relative high contribution from contemporary sources, suggested the differences of primary and secondary sources at the two sites. • 14 C-based source assessment of carbonaceous materials in PM 2.5 aerosols. • All carbon fractions are mixtures of contemporary and fossil carbon. • The source of carbon fractions in aerosols is heterogeneous.

Soil organic amendments: impacts on sorption of organophosphate pesticides on an alluvial soil

Soil organic carbon enrichment by addition of organic amendments (OAs) is a common agricultural and gardening practice. Such amendments can cause ambiguous environmental effects; it could enhance the sorption of pesticides by increasing soil organic carbon content, and on the contrary, dissolved organic matter (DOM) from OAs could facilitate their leaching. This study evaluated the influence of OAs, mixed waste compost, and dried goat organic manure on the sorption of organophosphates, dichlorvos, and chlorpyrifos. Soil (15 cm depth) was collected from an agricultural field and stored. Dissolved organic matter (DOM) extracted from the amendments and the amended soils was characterized by fluorescence spectroscopy and Fourier transform infrared spectroscopy (FT-IR). Initially, studies were carried out to evaluate the effect of DOM from organic amendments (OA-DOM) and dissolved humic acids (HAs) as model DOM on the sorption of selected pesticides. In the later part, OAs (2.5 and 5% w/w) were added to the soil, and sorption experiments were carried out using amended soil to understand the combined effects of insoluble and soluble organic carbon fraction. As dichlorvos sorption was found to be very low, desorption experiments were conducted only for chlorpyrifos using 0.01 M CaCl2 and DOM solutions. The spectroscopic characterization of OA-DOM revealed that it mainly contained large amounts of highly humified and aromatic material. OA-DOM and HAs had a similar effect on pesticide sorption leading to a slight but not significant increase in dichlorvos sorption while a substantial reduction in chlorpyrifos sorption was observed. Surface tension analysis highlighted that OA-DOM and HAs might have caused greater solubilization of chlorpyrifos, thus reducing sorption. Further, it also promoted greater desorption of adsorbed chlorpyrifos. These results seem to be related to the humified and aromatic nature of OA-DOM and HAs, determining the interactions between hydrophobic chlorpyrifos and DOM. On the contrary, the addition of OAs to soil promoted greater chlorpyrifos and dichlorvos sorption, but a clear correlation between increase in soil organic carbon and pesticide sorption could not be established. The study highlighted that the net effect of OA application was an increase in pesticide sorption that depended on the nature of DOM and pesticide properties. The interactions of hydrophobic chlorpyrifos with DOM can lead to a significant reduction in sorption to such an extent that the sorption in the presence of substantial DOM concentration can be less than the sorption without it.

Oceanographic influences on the stability of the Cosgrove Ice Shelf, Antarctica

Ferrero Bay, located in eastern Pine Island Bay (PIB) of the Amundsen Sea Embayment, is one of the largest and southernmost fjords yet studied in Antarctica. High-resolution multibeam swath bathymetric data, chirp sonar sub-bottom profiles, and three Kasten cores were collected in Ferrero Bay during the IB Oden Southern Ocean 2009–2010 cruise (OSO0910). Core KC-15 from the inner bay yielded two carbonate ages providing a minimum age for ice sheet recession from this sector of PIB by ~11 cal. kyr BP. In total, seven additional acid insoluble organic (AIO) fraction radiocarbon ages provide a linear age model with an R2 of 0.99. Variations in magnetic susceptibility, grain size, total organic carbon (TOC) and nitrogen, diatom abundance, and foraminiferal assemblage and abundance are used to interpret glacial history and paleoceanographic conditions. Grounding line retreat was characterized by advection of planktic foraminifera beneath an ice shelf that may have extended across the middle continental shelf. Following initial deglaciation, the Cosgrove Ice Shelf covered Ferrero Bay, and productivity was virtually absent during the mid-Holocene, while benthic foraminifera indicate periodic incursion of warm Circumpolar Deep Water. The ice shelf persisted until 2.3 cal. kyr BP, when TOC and diatom abundance increased as the bay opened and coastal areas deglaciated. Abundant diatoms demonstrate open marine conditions and seasonal sea ice during the recent open water phase, while high benthic foraminiferal abundance indicates active benthos. The retreat of the Cosgrove Ice Shelf was out of phase with Antarctic Peninsula ice shelves and ice-core proxy temperatures, implying that it did not respond to Holocene climate events but rather to the influence of Circumpolar Deep Water and possibly to internal glacial dynamics.

Sediment chronology in Antarctic deglacial sediments: Reconciling organic carbon 14C ages to carbonate 14C ages using Ramped PyrOx

We present the first study which directly compares carbonate radiocarbon (14C) dates with the Ramped PyrOx (RP) radiocarbon dating technique within a single sediment core, and we confirm the utility for the latter constructing chronologies of high latitude, Holocene marine margin sediment successions. Historically, the heavily detrital nature of Antarctic margin sedimentary organic material and lack of carbonate preservation have made these sediments difficult to date accurately. Here, we use archived cores with existing foraminiferal ages to compare with RP dates at equal or similar depth intervals. The lowest temperature RP splits were integrated over narrower intervals than in previous studies to reduce the amount of mixing with older, more thermochemically stable end-members during pyrolytic decomposition. Ages of the low-temperature RP splits coincide with their corresponding carbonate counterparts, suggesting that the RP 14C dating method is a reliable alternative to carbonate dates in sediments where carbonates are absent or not sufficiently preserved for 14C dating. The rarity of calcareous material in most Antarctic sediments often obligates the use of the bulk acid insoluble organic (AIO) fraction of the sediment, which can be problematic because of contamination by older carbon. The bulk AIO 14C ages, which are calculated using the weighted arithmetic mean of all RP splits of individual samples, show that age reversals and biases can occur using bulk AIO dates for age models because of variable proportions of pre-aged organic matter down-core. The application of the RP dating method can reduce these effects to produce a more reliable chronology that is statistically identical to the foraminiferal dating chronology.

Austromegabalanus psittacus barnacle shell structure and proteoglycan localization and functionality.

Comparative analyzes of biomineralization models have being crucial for the understanding of the functional properties of biominerals and the elucidation of the processes through which biomacromolecules control the synthesis and structural organization of inorganic mineral-based biomaterials. Among calcium carbonate-containing bioceramics, egg, mollusk and echinoderm shells, and crustacean carapaces, have being fairly well characterized. However, Thoraceca barnacles, although being crustacea, showing molting cycle, build a quite stable and heavily mineralized shell that completely surround the animal, which is for life firmly cemented to the substratum. This makes barnacles an interesting model for studying processes of biomineralization. Here we studied the main microstructural and ultrastructural features of Austromegabalanus psittacus barnacle shell, characterize the occurrence of specific proteoglycans (keratan-, dermatan- and chondroitin-6-sulfate proteoglycans) in different soluble and insoluble organic fractions extracted from the shell, and tested them for their ability to crystallize calcium carbonate in vitro. Our results indicate that, in the barnacle model, proteoglycans are good candidates for the modification of the calcite crystal morphology, although the cooperative effect of some additional proteins in the shell could not be excluded.

Role of goethite during air-oxidation of PAH-contaminated soils

The impact of goethite on air-oxidation of PAH-contaminated soils was studied through two sets of experiments. (i) Soil extractable organic matter (EOM) and (ii) whole coking plant soils were oxidized at 60 and 100°C for 160d, with/without goethite. Organic matter (OM) mineralization was monitored via CO2 production and polycyclic aromatic compounds (PACs) oxidation was investigated by GC–MS analyses. The decrease in EOM and PAH contents, and the oxygenated-PAC production observed during EOM oxidation, were enhanced by the presence of goethite. PACs were likely transformed at the goethite surface through electron transfer process. Mass carbon balance revealed a transfer from EOM to the insoluble organic fraction indicating condensation/polymerization of organics. Soil oxidation induced a decrease in EOM, PAH but also in oxygenated-PAC contents, underscoring different oxidation or polymerization behavior in soil. The goethite addition had a lesser impact suggesting that indigenous minerals played an important role in PAC oxidation.

Biogenicity and Syngeneity of Organic Matter in Ancient Sedimentary Rocks: Recent Advances in the Search for Evidence of Past Life

The past decade has seen an explosion of new technologies for assessment of biogenicity and syngeneity of carbonaceous material within sedimentary rocks. Advances have been made in techniques for analysis of in situ organic matter as well as for extracted bulk samples of soluble and insoluble (kerogen) organic fractions. The in situ techniques allow analysis of micrometer-to-sub-micrometer-scale organic residues within their host rocks and include Raman and fluorescence spectroscopy/imagery, confocal laser scanning microscopy, and forms of secondary ion/laser-based mass spectrometry, analytical transmission electron microscopy, and X-ray absorption microscopy/spectroscopy. Analyses can be made for chemical, molecular, and isotopic composition coupled with assessment of spatial relationships to surrounding minerals, veins, and fractures. The bulk analyses include improved methods for minimizing contamination and recognizing syngenetic constituents of soluble organic fractions as well as enhanced spectroscopic and pyrolytic techniques for unlocking syngenetic molecular signatures in kerogen. Together, these technologies provide vital tools for the study of some of the oldest and problematic carbonaceous residues and for advancing our understanding of the earliest stages of biological evolution on Earth and the search for evidence of life beyond Earth. We discuss each of these new technologies, emphasizing their advantages and disadvantages, applications, and likely future directions.

New constraints on the timing of West Antarctic Ice Sheet retreat in the eastern Amundsen Sea since the Last Glacial Maximum

Glaciers flowing into the Amundsen Sea Embayment (ASE) account for >35% of the total discharge of the West Antarctic Ice Sheet (WAIS) and have thinned and retreated dramatically over the past two decades. Here we present detailed marine geological data and an extensive new radiocarbon dataset from the eastern ASE in order to constrain the retreat of the WAIS since the Last Glacial Maximum (LGM) and assess the significance of these recent changes. Our dating approach, relying mainly on the acid insoluble organic (AIO) fraction, utilises multi-proxy analyses of the sediments to characterise their lithofacies and determine the horizon in each core that would yield the most reliable age for deglaciation. In total, we dated 69 samples and show that deglaciation of the outer shelf was underway before 20,600 calibrated years before present (calyrBP), reaching the mid-shelf by 13,575calyrBP and the inner shelf to within ca. 150km of the present grounding line by 10,615calyrBP. The timing of retreat is broadly consistent with previously published radiocarbon dates on biogenic carbonate from the eastern ASE as well as AIO 14C ages from the western ASE and provides new constraints for ice sheet models. The overall retreat trajectory – slow on the outer shelf, more rapid from the middle to inner shelf – clearly highlights the importance of reverse bedslopes in controlling phases of accelerated groundling line retreat. Despite revealing these broad scale trends, the current dataset does not capture detailed changes in ice flow, such as stillstands during grounding line retreat (i.e., deposition of grounding zone wedges) and possible readvances as depicted in the geomorphological record.

Stable N and C isotopes in the organic matrix of fish otoliths: validation of a new approach for studying spatial and temporal changes in the trophic structure of aquatic ecosystems

Stable isotope studies of long-term ecosystem change are often hampered by lack of archived tissue samples. Here, we provide a reliable method for extracting the organic matrix from fish otoliths, demonstrate differences in isotope values between the soluble and insoluble organic fractions, and provide the trophic enrichment factors (ε). The analyses were performed on otoliths from wild-caught adult Atlantic cod (Gadus morhua) and otoliths from a 6-month diet-switch experiment with juvenile cod. Acid hydrolysis of otolith powder followed by ultrafiltration enabled us to purify and separate the soluble and insoluble organic material. There was a significant 1.72‰ and 0.15‰ difference in δ15N and δ13C, respectively, between the soluble and insoluble organic fraction of the otolith. This emphasizes the need for separation of the two fractions before analysis. The diet-specific trophic enrichment (εotolith-diet) in the soluble fraction varied between −0.20‰ and 0.31‰ for nitrogen and between 0.09‰ and 0.23‰ for carbon. In conclusion, the organic matrix of otoliths provides an attractive archive of organic material for ecological stable isotope analysis that has the potential to provide important insights into historic changes in the trophic structure of aquatic ecosystems.

Cloud condensation nuclei closure study on summer arctic aerosol

Abstract. We present an aerosol – cloud condensation nuclei (CCN) closure study on summer high Arctic aerosol based on measurements that were carried out in 2008 during the Arctic Summer Cloud Ocean Study (ASCOS) on board the Swedish ice breaker Oden. The data presented here were collected during a three-week time period in the pack ice (>85° N) when the icebreaker Oden was moored to an ice floe and drifted passively during the most biological active period into autumn freeze up conditions. CCN number concentrations were obtained using two CCN counters measuring at different supersaturations. The directly measured CCN number concentration was then compared with a CCN number concentration calculated using both bulk aerosol mass composition data from an aerosol mass spectrometer (AMS) and aerosol number size distributions obtained from a differential mobility particle sizer, assuming κ-Köhler theory, surface tension of water and an internally mixed aerosol. The last assumption was supported by measurements made with a hygroscopic tandem differential mobility analyzer (HTDMA) for particles >70 nm. For the two highest measured supersaturations, 0.73 and 0.41%, closure could not be achieved with the investigated settings concerning hygroscopicity and density. The calculated CCN number concentration was always higher than the measured one for those two supersaturations. This might be caused by a relative larger insoluble organic mass fraction of the smaller particles that activate at these supersaturations, which are thus less good CCN than the larger particles. On average, 36% of the mass measured with the AMS was organic mass. At 0.20, 0.15 and 0.10% supersaturation, closure could be achieved with different combinations of hygroscopic parameters and densities within the uncertainty range of the fit. The best agreement of the calculated CCN number concentration with the observed one was achieved when the organic fraction of the aerosol was treated as nearly water insoluble (κorg=0.02), leading to a mean total κ, κtot, of 0.33 ± 0.13. However, several settings led to closure and κorg=0.2 is found to be an upper limit at 0.1% supersaturation. κorg≤0.2 leads to a κtot range of 0.33 ± 013 to 0.50 ± 0.11. Thus, the organic material ranges from being sparingly soluble to effectively insoluble. These results suggest that an increase in organic mass fraction in particles of a certain size would lead to a suppression of the Arctic CCN activity.

Deglacial history of the West Antarctic Ice Sheet in the western Amundsen Sea Embayment

The Amundsen Sea Embayment (ASE) drains approximately 35% of the West Antarctic Ice Sheet (WAIS) and is one of the most rapidly changing parts of the cryosphere. In order to predict future ice sheet behaviour, modellers require long-term records of ice-sheet melting to constrain and build confidence in their simulations. Here, we present detailed marine geological and radiocarbon data along three palaeo-ice stream tributary troughs in the western ASE to establish vital information on the timing of deglaciation of the WAIS since the Last Glacial Maximum (LGM). We have undertaken multi-proxy analyses of the cores (core description, shear strength, x-radiographs, magnetic susceptibility, wet bulk density, total organic carbon/nitrogen, carbonate content and clay mineral analyses) in order to: (1) characterise the sedimentological facies and depositional environments; and (2) identify the horizon(s) in each core that would yield the most reliable age for deglaciation. In accordance with previous studies we identify three key facies, which offer the most reliable stratigraphies for dating deglaciation by recording the transition from a grounded ice sheet to open marine environments. These facies are: i) subglacial, ii) proximal grounding line, and iii) seasonal open marine. In addition, we incorporate ages from other facies (e.g., glaciomarine diamictons deposited at some distance from the grounding line, such as glaciogenic debris flows and iceberg-rafted diamictons and turbates) into our deglacial model. In total, we have dated 78 samples (mainly the acid insoluble organic (AIO) fraction, but also calcareous foraminifers), which include 63 downcore and 15 surface samples. Through careful sample selection prior to dating, we have established a robust deglacial chronology for this sector of the WAIS. Our data show that deglaciation of the western ASE was probably underway as early as 22,351 calibrated years before present (cal yr BP), reaching the mid-shelf by 13,837 cal yr BP and the inner shelf to within c.10–12 km of the present ice shelf front between 12,618 and 10,072 cal yr BP. The deglacial steps in the western ASE broadly coincide with the rapid rises in sea-level associated with global meltwater pulses 1a and 1b, although given the potential dating uncertainty, additional, more precise ages are required before these findings can be fully substantiated. Finally, we show that the rate of ice-sheet retreat increased across the deep (up to1600 m) basins of the inner shelf, highlighting the importance of reverse slope and pinning points in accelerated phases of deglaciation.

Comparative analysis and geological significance of kerogen isolated using open-system (palynological) versus chemically and volumetrically conservative closed-system methods

Characterization of kerogen, the insoluble organic fraction of sedimentary rocks, is of key importance in investigations of the geochemistry of ancient depositional systems, paleo climates, basin thermal history, and petroleum generation systematics. Furthermore, exploitation of organic-rich oil shales as unconventional petroleum resources requires understanding of the physical chemistry of the kerogen conversion reactions and the coking behavior. These issues can be effectively addressed only if pure, representative kerogen is obtained from the rock matrix using chemically and volumetrically conservative methods that preclude losses, alteration, or fractionation of the organic matter. Isolation of representative and pure kerogen concentrates from the rock matrix is difficult. Many methods have been used over the years with various degrees of success. Most are based on traditional palynological processing approaches in open systems that commonly yield fractionated products, generally contaminated with pyrite and insoluble neo-fluorides. A few are based on complex sealed-system procedures that purport to conserve the entire kerogen with no fractionation, no alteration and no contamination. This study focuses on a comparative analysis of kerogens isolated with the conventional open-system approach (HCl/HF/heavy liquid separation) and kerogens concentrated with a fully automated, conservative, closed-system method (HCl/HF/CrCl 2) under an inert N 2 atmosphere. Source-rock samples of various richness, kerogen types, ages, depositional environments, lithologies and thermal histories were selected for kerogen isolation using the two approaches. Kerogen recovery efficiency, progress of the processes and quality of the isolated kerogens were monitored via mass balance calculations, organic elemental analysis and X-ray diffraction analysis. The inherent inadequacy in the open-system approach for geochemical research and the improved features of the chemically and volumetrically conservative method are documented.

Cloud Activating Properties of Aerosol Observed during CELTIC

Abstract Measurements of aerosol size distribution, chemical composition, and cloud condensation nuclei (CCN) concentration were performed during the Chemical Emission, Loss, Transformation, and Interactions with Canopies (CELTIC) field program at Duke Forest in North Carolina. A kinetic model of the cloud activation of ambient aerosol in the chamber of the CCN instrument was used to perform an aerosol–CCN closure study. This study advances prior investigations by employing a novel fitting algorithm that was used to integrate scanning mobility particle sizer (SMPS) measurements of aerosol number size distribution and aerosol mass spectrometer (AMS) measurements of the mass size distribution for sulfate, nitrate, ammonium, and organics into a single, coherent description of the ambient aerosol in the size range critical to aerosol activation (around 100-nm diameter). Three lognormal aerosol size modes, each with a unique internally mixed composition, were used as input into the kinetic model. For the two smaller size modes, which control CCN number concentration, organic aerosol mass fractions for the defined cases were between 58% and 77%. This study is also unique in that the water vapor accommodation coefficient was estimated based on comparing the initial timing for CCN activation in the instrument chamber with the activation predicted by the kinetic model. The kinetic model overestimated measured CCN concentrations, especially under polluted conditions. Prior studies have attributed a positive model bias to an incomplete understanding of the aerosol composition, especially the role of organics in the activation process. This study shows that including measured organic mass fractions with an assumed organic aerosol speciation profile (pinic acid, fulvic acid, and levoglucosan) and an assumed organic aerosol solubility of 0.02 kg kg−1 still resulted in a significant model positive bias for polluted case study periods. The slope and y intercept for the CCN predicted versus CCN observed regression was found to be 1.9 and −180 cm−3, respectively. The overprediction generally does not exceed uncertainty limits but is indicative that a bias exists in the measurements or application of model. From this study, uncertainties in the particle number and mass size distributions as the cause for the model bias can be ruled out. The authors are also confident that the model is including the effects of growth kinetics on predicted activated number. However, one cannot rule out uncertainties associated with poorly characterized CCN measurement biases, uncertainties in assumed organic solubility, and uncertainties in aerosol mixing state. Sensitivity simulations suggest that assuming either an insoluble organic fraction or external aerosol mixing were both sufficient to reconcile the model bias.

酸素添加の形態が予燃焼室式ディーゼル機関の排出ガス特性に及ぼす影響

Ships have many advantages in loading capacities compared with vehicles. If the amount of NOx can be reduced by some way, ships can be equipped with oxygen permeable membranes as an oxygen generator that has recently shown a remarkable improvement in the performance of producing more oxygen for the purpose of PM (Particulate Matter) reduction.Therefore, the objective of this study is to examine the effect of oxygen addition on exhaust gas emissions for marine diesel engines.In the experiment oxygen was added to the air suction pipe of a pre-combustion chamber type diesel engine. Then oxygen was added to the exhaust gas pipe before DPF (Diesel Particulate Filter) .The results were as follows:(1) Oxygen addition to the air suction pipe of a pre-combustion chamber type diesel engine decreases both ISF (Insoluble Organic Fraction) and SOF (Soluble Organic Fraction) . Oxygen addition works very well especially at all loads for reduction of ISF with an increase of 2% in oxygen concentration.(2) Although oxygen addition to the air suction pipe of a pre-combustion chamber type diesel engine increases NOx emission. The NOx emission of a pre-combustion chamber type diesel engine is not so much as that of a direct injection type engine. The increase of NOx emission is saturated with further increasing engine load.(3) DPF was effective even in an ordinary type engine that has mechanical fuel injection system and no supercharger. The reduction rate was superior in ISF compared to SOF.(4) Oxygen addition before DPF has almost no effect on PM reduction.

Origin and distribution of biomarkers in the sulphur rich Utrillas coal basin – Teruel mining district – Spain

The Utrillas coal facies are located in the Maestrazgo basin in NE Spain. This mining district of Teruel contains sub-bituminous deposits from the Middle Albian (Lower Cretaceous 105 Ma) in areas near a delta estuary with abundant sulphur. The high sulphur content is due to an influx of sulphate caused by the geological recycling of Triassic gypsum from the catchment area into the delta estuary. In some outcrops, the weathered coal reveals leonardite deposits. The depositional environment of the basin originated coals, some of which are currently mined. The organic matter of the coals has been the object of scattered reports. Studies have focused on bulk pyrolysis parameters and microscopic observation in Utrillas samples, as well as the inorganic and insoluble organic fraction. We analysed the organic soluble extract of the Utrillas coals using GC–MS in order to characterize their aliphatic, aromatic and organosulphur compounds. The biomarker distribution allowed us to recognize different inputs, assess their depositional palaeoenvironment and finally determine their degree of maturity. In particular, homologous series of hopanes related to eubacteria were present. Biomarkers characteristic of higher plant inputs were also widely distributed (e.g. phyllocladane or C 29 steranes). The presence of linear alkylbenzenes allowed us to recognize the palaeodepositional reducing environments where they were deposited. Specifically, thienylhopanes were associated with sulphur-reducing environments. Finally, the abundance of unsaturated biomarkers such as diacholestenes indicated low-maturity coals. Various aromatic ratios such as the methylphenanthrene index also suggested diagenesis in the initial stage.