Organic geochemistry of ODP Hole 162-985A sediments

Dark, organic-rich sediments were recovered from the lower Miocene section (~16.6 Ma) in Hole 985A in the Norway Basin during Ocean Drilling Program Leg 162. Organic carbon and total sulfur contents of the dark sediments showed a maximum concentration of 5.6 and 26.1 wt%, respectively. Sulfur enrichment in the sediments indicates that these dark layers were formed under anoxic conditions in bottom water. Four dark and eight greenish gray sediment samples, ranging in age from early Miocene to Pleistocene, were analyzed for lipid-class compounds (aliphatic hydrocarbons, fatty alcohols, and sterols) using gas chromatography (GC) and GC/mass spectrometry to better understand the formation processes of the organic-rich dark layers and to reconstruct the paleoenvironmental changes. The molecular distributions of n-alkanes and fatty alcohols indicate that terrigenous organic matter largely contributed to both types of sediments. Significant amounts of hopanoid hydrocarbons, such as diploptene and hop-17(21)-ene, however, were detected characteristically in the dark sediments, which suggests that prokaryotes such as methane-oxidizing bacteria or cyanobacteria may have significantly contributed to the formation of these organic-rich, dark sediments. These results indicate that the bottom waters of the Norway Basin had been subjected to anoxic conditions during the early Miocene.

(Table 1) Carbon and isotopic composition of organic carbon in sediments from DSDP Leg 56 Holes

We have analyzed inorganic and organic carbons and determined the isotopic composition of both sedimentary organic carbon and inorganic carbon in carbonates contained in sediments recovered from Holes 434, 434A, 434B, 435, and 435A in the landward slope of Japan and from Hole 436 in the oceanic slope of the Japan Trench. Both inorganic and organic carbons were assayed at the P. P. Shirshov Institute of Oceanology, in the same sample, using the Knopp technique and measuring evolved CO2 gravimetrically. Each sample was analyzed twice in parallel. Measurements were of a ±0.05 per cent accuracy and a probability level of 0.95. Carbon isotopic analysis was carried out on a MI-1305 mass spectrometer at the I. M. Gubkin Institute of Petrochemical and Gas Industry and the results presented as dC13 values related to the PDB standard. The procedure for preparing samples for organic carbon isotopic analysis involved (1) drying damp sediments at 60°C; (2) treating samples, while heating, with 10 N HCl to remove carbonate carbon; and (3) evaporating surplus HCl at 60°C. The organic substance was turned to CO2 by oxidizing it in an oxygen atmosphere. To prepare samples for inorganic carbon isotopic analysis we decomposed the carbonates with orthophosphoric acid and refined the gas evolved. The dC13 measurements, including a full cycle of sample preparation, were of a ±0.5 per cent accuracy and a probability level of 0.95.

Organic geochemistry on sediment profiles from the Arctic Ocean

During the ARCTIC '91-Expedition with RV 'Polarstern', several Multicorer and Kastenlot-cores were recovered along a profile crossing the eastern part of the Arctic Ocean. The investigated cores consist mainly of clayey-silty sediments, and some units with a higher sand content. In this thesis, detailed sedimentological and organic-geochemical investigations were performed. In part, the near surface sediments were AMS-14C dated making it possible to Interpret the results of the organic-geochemical investigations in terms of climatic changes (isotopic stage 2 to the Holocene). The more or less absence of foraminifers within the long cores prevented the development of an oxygen isotope stratigraphy. Only the results of core PS2174-5 from the Amundsen-Basin could be discussed in terms of the climatic change that could be dated back to oxygen isotope stage 7. Detailed organic-geochemical investigations in the central Arctic Ocean are rare. Therefore, several different organic-geochemical methods were used to obtain a wide range of data for the Interpretation of the organic matter. The high organic carbon content of the surface sediments is derived from a high input of terrigenous organic matter. The terrigenous organic material is most likely entrained within the sea-ice On the Siberian shelves and released during ice-drift over the Arctic Ocean. Other factors such as iceberg-transport and turbidites are also responsible for the high input of terrigenous organic matter. Due to the more or less closed sea-ice Cover, the Arctic Ocean is known as a low productivity system. A model shows, that only 2 % of the organic matter in central Arctic Ocean sediments is of a marine origin. The influence of the West-Spitsbergen current increases the marine organic matter content to 16 %. Short chain n-alkanes (C17 and C19) can be used as a marker of marine productivity in the Arctic Ocean. Higher contents of short chain n-alkanes exist in surface sediments of the Lomonosov-Ridge and the Makarov-Basin, indicating a higher marine productivity caused by a reduced sea-ice Cover. The Beaufort-Gyre and Transpolar-Drift drift Patterns could be responsible for the lower sea-ice distribution in this region. The sediments of Stage 2 and Stage 3 in this region are also dominated by a higher content of short chain-nalkanes indicating a comparable ice-drift Pattern during that time. The content and composition of organic carbon in the sediments of core PS2174-5 reflect glaciallinterglacial changes. Interglacial stages 7 and 5e show a low organic carbon content (C 0,5 %) and, as indicated by high hydrogen-indices, low CIN-ratios, higher content of n-alkanes (C17 and C19) and a higher opal content, a higher marine productivity. In the Holocene, a high content of foraminifers, coccoliths, ostracodes, and sponge spicules indicate higher surface-water productivity. Nevertheless, the low hydrogenindices reveal a high content of terrigenous organic matter. Therefore, the Holocene seems to be different from interglacials 7 and 5e. During the glacial periods (stages 6, upper 5, and 4), TOC-values are significantly higher (0.7 to 1.3 %). In addition, low hydrogen-indices, high CIN-ratios, low short chain n-alkanes and opal contents provide evidence for a higher input of terrigenous organic matter and reduced marine productivity. The high lignin content in core sections with high TOC-contents, substantiates the high input of terrigenous organic matter. Changes in the content and composition of the organic carbon is believed to vary with the fluctuations in sea-level and sea-ice coverage.

(Tables 1, 3) Component composition of organic particles in samples from ODP Site 131-808

Analysis of the palynofacies and miospore thermal alteration indices (TAI) of sediments from ODP Site 808 in the Nankai Trough was undertaken to determine (1) the source, depositional environment, and diagenesis of organic matter in the accreted sediments, and (2) the thermal structure and history of the prism and its relationship to fluid flow. Using the Hartax classification system, two palynofacies were recognized in the sedimentary sequence. Facies 1 occurs within the upper 600 m of trench-wedge turbidites (sedimentation rate > 1 km/m.y.) and contains >50% inertite particles. The rest of the assemblage is dominated by well-preserved phytoclasts and contains small amounts of poorly preserved phytoclasts and well-preserved scleratoclasts. Facies 2 occurs within the Shikoku Basin hemipelagites (600-1300 m below seafloor; sedimentation rate <150 m/m.y.) and contains over two-thirds inertite particles. The rest of the assemblage is dominated by poorly preserved phytoclasts. Miospores and marine phytoplankton compose only a small percentage of both palynofacies. Degraded organic matter is most noticeable in Facies 2, whereas its presence in Facies 1 is overshadowed by the high influx of well-preserved primary organic matter. Most of the degraded organic matter and inertite is interpreted to be reworked. Some of the degraded organic matter may be primary, and may have experienced more biodegradation and thermal alteration in Facies 2 than in Facies 1. TAI values indicate an immature stage of organic maturation (< 2) down to about 900 mbsf. Below this, samples show an increase with depth to a mature stage, reaching peak levels of about 3 just above basement. Samples from within the thrust fault and decollement zones do not show levels of maturity significantly greater than those of surrounding samples, leaving uncertain whether hot fluids have migrated along these fault boundaries in the past.

Geochemistry of labile organic matter in sediments and interstitial waters of ODP Sites 107-651 and 107-653

Sediment and interstitial water from Sites 651 and 653 (ODP Leg 107) were investigated by organic geochemical methods to characterize labile organic compound classes (amino compounds and carbohydrates) and to evaluate their progressive diagenetic and thermal degradation in deep-sea sediments. Downhole distribution of dissolved organic carbon (DOC) appears related to redox zones associated with bacterial activity and of diagenetic recrystallization of biogenic tests and not so much to organic matter concentrations in ambient sediments. DOC ranges from 250 to 8300 µmol/L (3-100.1 ppm). Amino acids contribute 10%-0.3% of DOC; carbohydrates range from 78 to 5 µmol/L. Rate of degradation of amino acids by thermal effects and/or bacterial activity at both sites (significantly different in sedimentation rates: average 41 cm/1000 yr in the top 300 m at Site 651, average 3.9 cm/1000 yr in the Pliocene/Quaternary sequence at Site 653 to 220 mbsf) is more dependent on exposure time rather than on the depth within the sediment column. Variability in neutral, acidic, and basic amino acid fractions of total amino acids (with a range of 1.1-0.02 µmol/g sediment; up to 2.5% of organic carbon) varies with carbonate content and by differences in thermal stability of amino acids. Distribution patterns of monosaccharides are interpreted to result from differences in organic matter sources, sedimentation rates, and the degree of organic matter decomposition prior to and subsequent to burial. Total particulate carbohydrates range from 1.82 to 0.21 µmol/g sediment and contribute about 8% to the sedimentary organic matter. Investigation of trace metals in the interstitial waters did not show any correlation of either DOC, amino compounds, or carbohydrates.

Total organic carbon in surface sediments of the Ob and Yenisei estuaries and adjacent coastal areas, appendix 1

Two main mechanisms are controlling the accumulation of organic matter in the sediments of the Kara Sea. The large rivers Ob and Yenisei supply significant quantities of freshwater onto the shelf (Lisitsyn and Vinogradov, 1995; Bobrovitskaya et al., 1996; Johnson et al., 1997) and deliver terrigenous organie matter and aquatic algae. Additionally, marine organic matter is produced in the water column. In order to distinguish between the different sources of the organic material maceral analysis, organic-geochemical bulk Parameters and biomarkers (short- and long-chain D-alkanes, fatty acids and pigments) were used to determine the quality (marine vs. terrigenous) and quantity of the organic carbon fraction in the surface sediments taken during the 28th cruise of RV Akademik Boris Petrov (Matthiessen and Stepanets, 1998) (Fig. 1). Previous organic-geochemical investigations (i.e., total organic-carbon content (TOC), hydrogen indices (Hl), CIN-ratios) indicate the importance of terrigenous input of organic matter (Galimov et al., 1996; Stein, 1996). Studies of lipid biomarkers in surface sediments in the Ob estuary show also a predominance of terrestrial constituents and an increase in planktonogenic and bacterial lipids further offshore (Belyaeva and Eglinton, 1997). In complex systems such as the Eurasian continental margin characterized by high input of terrestriallaquatic organic matter and strong seasonal variation in sea-ice Cover and primary productivity, the Interpretation of the organic geochemical data is much more complicated and restricted in comparison to similar data Sets from low-latitude open-ocean environments (Fahl and Stein, 1998). Microscopical studies (maceral analysisl palynology), however, allow a direct visual inspection of the particulate organic matter and allow to differentiate particles of different biological sources. Thus, a combination of both methods as shown in this study, yields a more precise identification of organic-carbon sources.

The issue in literary criticism,

"This book aims to give organic and systematic expression to the working principles of literary criticism ... It may, indeed, be viewed as an extended commentary on the Poetics of Aristotle."--Pref.

Measurements of indoor toxic VOC concentrations attributed to the residential storage of household products /

"HWRIC RR-074."

Organic Semiconducing Thin Films: Device Applications and Beyond

Thesis (Master's)--University of Washington, 2016-06

Grain coarsening of magnesium alloys by beryllium

A trace of beryllium can lead to dramatic grain coarsening in Mg-Al alloys at normal cooling rates. It is, however, unclear whether this effect applies to aluminium-free magnesium alloys or not. This work shows that a trace of beryllium also causes considerable grain coarsening in Mg-Zn, Mg-Ca, Mg-Ce and Mg-Nd alloys and hinders grain refinement of magnesium alloys by zirconium as well. (C) 2004 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Understanding conceptual schemas: exploring the role of application and IS domain knowledge

Although information systems (IS) problem solving involves knowledge of both the IS and application domains, little attention has been paid to the role of application domain knowledge. In this study, which is set in the context of conceptual modeling, we examine the effects of both IS and application domain knowledge on different types of schema understanding tasks: syntactic and semantic comprehension tasks and schema-based problem-solving tasks. Our thesis was that while IS domain knowledge is important in solving all such tasks, the role of application domain knowledge is contingent upon the type of understanding task under investigation. We use the theory of cognitive fit to establish theoretical differences in the role of application domain knowledge among the different types of schema understanding tasks. We hypothesize that application domain knowledge does not influence the solution of syntactic and semantic comprehension tasks for which cognitive fit exists, but does influence the solution of schema-based problem-solving tasks for which cognitive fit does not exist. To assess performance on different types of conceptual schema understanding tasks, we conducted a laboratory experiment in which participants with high- and low-IS domain knowledge responded to two equivalent conceptual schemas that represented high and low levels of application knowledge (familiar and unfamiliar application domains). As expected, we found that IS domain knowledge is important in the solution of all types of conceptual schema understanding tasks in both familiar and unfamiliar applications domains, and that the effect of application domain knowledge is contingent on task type. Our findings for the EER model were similar to those for the ER model. Given the differential effects of application domain knowledge on different types of tasks, this study highlights the importance of considering more than one application domain in designing future studies on conceptual modeling.

Microstructures and electrolytic properties of yttrium-doped ceria electrolytes: Dopant concentration and grain size dependences

The microstructures and electrolytic properties of YxCe1-xO2-x/2 (x = 0.10-0.25) electrolytes with average grain size in the range 90 nm-1.7 mu m were systematically investigated. Through detailed transmission electron microscopy characterization, nanosized domains were observed. The relationship of the domains, the doping level and grain sizes were determined, and their impacts on the electrolytic properties were systematically studied. It was found that the formation of domains has a negative impact on the electrolytic properties, so that electrolytic properties can be adjusted through careful control of domain formation, doping level and grain size. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effects of grain size and microstructure on threshold values and near threshold crack growth in powder-formed Ni-base superalloy

Threshold stress intensity values, ranging from ∼6 to 16 MN m −3/2 can be obtained in powder-formed Nimonic AP1 by changing the microstructure. The threshold and low crack growth rate behaviour at room temperature of a number of widely differing API microstructures, with both ‘necklace’ and fully recrystallized grain structures of various sizes and uniform and bimodal γ′-distributions, have been investigated. The results indicate that grain size is an important microstructural parameter which can control threshold behaviour, with the value of threshold stress intensity increasing with increasing grain size, but that the γ′-distribution is also important. In this Ni-base alloy, as in many others, near threshold fatigue crack growth occurs in a crystallographic manner along {111} planes. This is due to the development of a dislocation structure involving persistent slip bands on {111} planes in the plastic zone, caused by the presence of ordered shearable precipitates in the microstructure. However, as the stress intensity range is increased, a striated growth mode takes over. The results presented show that this transition from faceted to striated growth is associated with a sudden increase in crack propagation rate and occurs when the size of the reverse plastic zone at the crack tip becomes equal to the grain size, independent of any other microstructural variables.

Probabilistic Approach to the Neumann Problem for a Symmetric Operator

2000 Mathematics Subject Classification: Primary 60J45, 60J50, 35Cxx; Secondary 31Cxx.

A tudásreprezentáció és a tudásmegosztás információtechnológiai megoldásai a személyazonosság-menedzsment területén (Knowledge Representation and Sharing for Identity Management Domain)

A személyazonosság-menedzsment napjaink fontos kutatási területe mind elméleti, mind gyakorlati szempontból. A szakterületen megvalósuló együttműködés, elektronikus tudásáramoltatás és csere hosszú távon csak úgy képzelhető el, hogy az azonos módon történő értelmezést automatikus eszközök támogatják. A szerző cikkében azokat a kutatási tevékenységeket foglalja össze, amelyeket - felhasználva a tudásmenedzsment, a mesterséges intelligencia és az információtechnológia eszközeit - a személyazonosság-menedzsment terület fogalmi leképezésére, leírására használt fel. Kutatási célja olyan közös fogalmi bázis kialakítása volt személyazonosság-menedzsment területre, amely lehetővé teszi az őt körülvevő multidimenzionális környezet kezelését. A kutatás kapcsolódik a GUIDE kutatási projekthez is, amelynek a szerző résztvevője. ______________ Identity management is an important research field from theoretical and practical aspects as well. The task itself is not new, identification and authentication was necessary always in public administration and business life. Information Society offers new services for citizens, which dramatically change the way of administration and results additional risks and opportunities. The goal of the demonstrated research was to formulate a common basis for the identity management domain in order to support the management of the surrounding multidimensional environment. There is a need for capturing, mapping, processing knowledge concerning identity management in order to support reusability, interoperability; to help common sharing and understanding the domain and to avoid inconsistency. The paper summarizes research activities for the identification, conceptualisation and representation of domain knowledge related to identity management, using the results of knowledge management, artificial intelligence and information technology. I utilized the experiences of Guide project, in which I participate. The paper demonstrates, that domain ontologies could offer a proper solution for identity management domain conceptualisation.