Greigite formed in early Pleistocene lacustrine sediments from the Heqing Basin, southwest China, and its paleoenvironmental implications

NASA Astrophysics Data System (ADS)

Qiang, Xiaoke; Xu, Xinwen; Zhao, Hui; Fu, Chaofeng

2018-05-01

The ferrimagnetic iron sulfide greigite (Fe3S4) occurs widely in sulfidic lacustrine and marine sedimentary environments. Knowledge of its formation and persistence is important for both magnetostratigraphic and paleoenvironmental studies. Although the formation mechanism of greigite has been widely demonstrated, the sedimentary environments associated with greigite formation in lakes, especially on relatively long timescales, are poorly understood. A long and continuous sequence of Pleistocene lacustrine sediments was recovered in the Heqing drill core from southwestern China, which provides an outstanding record of continental climate and environment. Integrated magnetic, geochemical, and paleoclimatic analysis of the lacustrine sequence provides an opportunity to improve our understanding of the environmental controls on greigite formation. Rock magnetic and scanning electron microscope analyses of selected samples from the core reveal that greigite is present in the lower part of the core (part 1, 665.8-372.5 m). Greigite occurs throughout this interval and is the dominant magnetic mineral, irrespective of the climatic state. The magnetic susceptibility (χ) record, which is mainly controlled by the concentration of greigite, matches well with variations in the Indian Summer Monsoon (ISM) index and total organic carbon (TOC) content, with no significant time lag. This indicates that the greigite formed during early diagenesis. In greigite-bearing intervals, with the χ increase, Bc value increase and tends to be stable at about 50 mT. Therefore, we suggest that χ values could estimate the variation of greigite concentration approximately in the Heqing core. Greigite favored more abundant in terrigenous-rich and organic-poor layers associated with weak summer monsoon which are characterized by high χ values, high Fe content, high Rb/Sr ratio and low TOC content. Greigite enhancement can be explained by variations in terrigenous inputs. Our studies demonstrate

The Index to Marine and Lacustrine Geological Samples: Improving Sample Accessibility and Enabling Current and Future Research

NASA Astrophysics Data System (ADS)

Moore, C.

2011-12-01

included in anticipation of opportunities for interconnectivity with Integrated Earth Data Applications (IEDA) systems. To promote interoperability and broaden exposure via the semantic web, NGDC is publishing lithologic classification schemes and terminology used in the Index as Simple Knowledge Organization System (SKOS) vocabularies, coordinating with R2R and the Consortium for Ocean Leadership for consistency. Availability in SKOS form will also facilitate use of the vocabularies in International Standards Organization (ISO) 19115-2 compliant metadata records. NGDC provides stewardship for the Index on behalf of U.S. repositories as the NSF designated "appropriate National Data Center" for data and metadata pertaining to sea floor samples as specified in the 2011 Division of Ocean Sciences Sample and Data Policy, and on behalf of international partners via a collocated World Data Center. NGDC operates on the Open Archival Information System (OAIS) reference model. Active Partners: Antarctic Marine Geology Research Facility, Florida State University; British Ocean Sediment Core Research Facility; Geological Survey of Canada; Integrated Ocean Drilling Program; Lamont-Doherty Earth Observatory; National Lacustrine Core Repository, University of Minnesota; Oregon State University; Scripps Institution of Oceanography; University of Rhode Island; U.S. Geological Survey; Woods Hole Oceanographic Institution.

78 FR 33475 - Core Principles and Other Requirements for Swap Execution Facilities

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-04

... Core Principles and Other Requirements for Swap Execution Facilities; Final Rule #0;#0;Federal Register... FUTURES TRADING COMMISSION 17 CFR Part 37 RIN 3038-AD18 Core Principles and Other Requirements for Swap... Core Principles 1. Subpart B--Core Principle 1 (Compliance With Core Principles) 2. Subpart C--Core...

Prehistoric earthquake history revealed by lacustrine slump deposits

NASA Astrophysics Data System (ADS)

Schnellmann, Michael; Anselmetti, Flavio S.; Giardini, Domenico; McKenzie, Judith A.; Ward, Steven N.

2002-12-01

Five strong paleoseismic events were recorded in the past 15 k.y. in a series of slump deposits in the subsurface of Lake Lucerne, central Switzerland, revealing for the first time the paleoseismic history of one of the most seismically active areas in central Europe. Although many slump deposits in marine and lacustrine environments were previously attributed to historic earthquakes, the lack of detailed three-dimensional stratigraphic correlation in combination with accurate dating hampered the use of multiple slump deposits as paleoseismic indicators. This study investigated the fingerprint of the well-described A.D. 1601 earthquake (I = VII VIII, Mw ˜ 6.2) in the sediments of Lake Lucerne. The earthquake triggered numerous synchronous slumps and megaturbidites within different subbasins of the lake, producing a characteristic pattern that can be used to assign a seismic triggering mechanism to prehistoric slump events. For each seismic event horizon, the slump synchronicity was established by seismic-stratigraphic correlation between individual slump deposits through a quasi-three-dimensional high-resolution seismic survey grid. Four prehistoric events, dated by accelerator mass spectrometry, 14C measurements, and tephrochronology on a series of long gravity cores, occurred at 2420, 9770, 13,910, and 14,560 calendar yr ago. These recurrence times are essential factors for assessing seismic hazard in the area. The seismic hazard for lakeshore communities is additionally amplified by slump-induced tsunami and seiche waves. Numerical modeling of such tsunami waves revealed wave heights to 3 m, indicating tsunami risk in lacustrine environments.

Fluvial to Lacustrine Facies Transitions in Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Sumner, Dawn Y.; Williams, Rebecca M. E.; Schieber, Juergen; Palucis, Marisa C.; Oehler, Dorothy Z.; Mangold, Nicolas; Kah, Linda C.; Gupta, Sanjeev; Grotzinger, John P.; Grant, John A., III;

76 FR 1213 - Core Principles and Other Requirements for Swap Execution Facilities

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-07

... Part II Commodity Futures Trading Commission 17 CFR Part 37 Core Principles and Other Requirements... RIN Number 3038-AD18 Core Principles and Other Requirements for Swap Execution Facilities AGENCY... Compliance With the Core Principles III. Effective Date and Transition Period IV. Related Matters A...

Oligocene lacustrine tuff facies, Abu Treifeya, Cairo-Suez Road, Egypt

NASA Astrophysics Data System (ADS)

Abdel-Motelib, Ali; Kabesh, Mona; El Manawi, Abdel Hamid; Said, Amir

2015-02-01

Field investigations in the Abu Treifeya area, Cairo-Suez District, revealed the presence of Oligocene lacustrine volcaniclastic deposits of lacustrine sequences associated with an Oligocene rift regime. The present study represents a new record of lacustrine zeolite deposits associated with saponite clay minerals contained within reworked clastic vitric tuffs. The different lithofacies associations of these clastic sequences are identified and described: volcaniclastic sedimentary facies represent episodic volcaniclastic reworking, redistribution and redeposition in a lacustrine environment and these deposits are subdivided into proximal and medial facies. Zeolite and smectite minerals are mainly found as authigenic crystals formed in vugs or crusts due to the reaction of volcanic glasses with saline-alkaline water or as alteration products of feldspars. The presence of abundant smectite (saponite) may be attributed to a warm climate, with alternating humid and dry conditions characterised by the existence of kaolinite. Reddish iron-rich paleosols record periods of non-deposition intercalated with the volcaniclastic tuff sequence.

A great volcanic eruption around AD 1300 recorded in lacustrine sediment from Dongdao Island, South China Sea

NASA Astrophysics Data System (ADS)

Yang, Zhongkang; Long, Nanye; Wang, Yuhong; Zhou, Xin; Liu, Yi; Sun, Liguang

2017-02-01

The contents of Ti, Al and Fe 2 O 3 in a lacustrine sediment core (DY6) collected from Dongdao Island, South China Sea (SCS), were determined to be much higher than those in the three major sediment end-members (coral sand, guano and plants), and their likely sources include terrigenous dust and volcanic ash. At 61 cm (˜AD 1300), the contents of Ti, Al and Fe 2 O 3 have an abnormally high spike, which cannot be explained by terrigenous dust. The Sr and Nd isotope compositions at 61 cm are in excellent agreement with those in volcanic materials, but they are significantly different from those in terrigenous dust, implying a possible material input from historical volcanic eruptions in the lacustrine sediment DY6. The documented great Samalas volcanic eruption at AD 1257 in Indonesia is likely the candidate for this volcanic eruption.

Architecture and reservoir quality of low-permeable Eocene lacustrine turbidite sandstone from the Dongying Depression, East China

NASA Astrophysics Data System (ADS)

Munawar, Muhammad Jawad; Lin, Chengyan; Chunmei, Dong; Zhang, Xianguo; Zhao, Haiyan; Xiao, Shuming; Azeem, Tahir; Zahid, Muhammad Aleem; Ma, Cunfei

2018-05-01

The architecture and quality of lacustrine turbidites that act as petroleum reservoirs are less well documented. Reservoir architecture and multiscale heterogeneity in turbidites represent serious challenges to production performance. Additionally, establishing a hierarchy profile to delineate heterogeneity is a challenging task in lacustrine turbidite deposits. Here, we report on the turbidites in the middle third member of the Eocene Shahejie Formation (Es3), which was deposited during extensive Middle to Late Eocene rifting in the Dongying Depression. Seismic records, wireline log responses, and core observations were integrated to describe the reservoir heterogeneity by delineating the architectural elements, sequence stratigraphic framework and lithofacies assemblage. A petrographic approach was adopted to constrain microscopic heterogeneity using an optical microscope, routine core analyses and X-ray diffraction (XRD) analyses. The Es3m member is interpreted as a sequence set composed of four composite sequences: CS1, CS2, CS3 and CS4. A total of forty-five sequences were identified within these four composite sequences. Sand bodies were mainly deposited as channels, levees, overbank splays, lobes and lobe fringes. The combination of fining-upward and coarsening-upward lithofacies patterns in the architectural elements produces highly complex composite flow units. Microscopic heterogeneity is produced by diagenetic alteration processes (i.e., feldspar dissolution, authigenic clay formation and quartz cementation). The widespread kaolinization of feldspar and mobilization of materials enhanced the quality of the reservoir by producing secondary enlarged pores. In contrast, the formation of pore-filling authigenic illite and illite/smectite clays reduced its permeability. Recovery rates are higher in the axial areas and smaller in the marginal areas of architectural elements. This study represents a significant insight into the reservoir architecture and

Core characterization of the new CABRI Water Loop Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ritter, G.; Rodiac, F.; Beretz, D.

2011-07-01

The CABRI experimental reactor is located at the Cadarache nuclear research center, southern France. It is operated by the Atomic Energy Commission (CEA) and devoted to IRSN (Institut de Radioprotection et de Surete Nucleaire) safety programmes. It has been successfully operated during the last 30 years, enlightening the knowledge of FBR and LWR fuel behaviour during Reactivity Insertion Accident (RIA) and Loss Of Coolant Accident (LOCA) transients in the frame of IPSN (Institut de Protection et de Surete Nucleaire) and now IRSN programmes devoted to reactor safety. This operation was interrupted in 2003 to allow for a whole facility renewalmore » programme for the need of the CABRI International Programme (CIP) carried out by IRSN under the OECD umbrella. The principle of operation of the facility is based on the control of {sup 3}He, a major gaseous neutron absorber, in the core geometry. The purpose of this paper is to illustrate how several dosimetric devices have been set up to better characterize the core during the upcoming commissioning campaign. It presents the schemes and tools dedicated to core characterization. (authors)« less

Sulfur Geochemistry of a Lacustrine Record from Taiwan Reveals Enhanced Marine Aerosol Input during the Early Holocene

PubMed Central

Ding, Xiaodong; Li, Dawei; Zheng, Liwei; Bao, Hongyan; Chen, Huei-Fen; Kao, Shuh-Ji

2016-01-01

Lacustrine record of marine aerosol input has rarely been documented. Here, we present the sulfur geochemistry during the last deglaciation and early Holocene of a sediment core retrieved from the Dongyuan Lake in southern Taiwan. An unusually high sulfur peak accompanying pyrite presence is observed at 10.5 ka BP. Such high sulfur content in lacustrine record is unusual. The δ34S of sulfur varied from +9.5 to + 17.1‰ with two significant positive shifts at 10.5 and 9.4 ka BP. The sources of sulfur and potential processes involving the sulfur isotope variation including bacterial sulfate reduction, volcanic emissions, in-catchment sulfide oxidation and marine aerosol input are discussed. Enhanced marine aerosol input is the most likely explanation for such sulfur peaks and δ34S shifts. The positive δ34S shifts appeared concurrently with the maximum landslide events over Taiwan resulted from enhanced typhoon activities. The synchronicity among records suggests that increased typhoon activities promoted sea spray, and consequently enhanced the marine aerosol input with 34S-enriched sulfate. Our sulfur geochemistry data revealed sea spray history and marine influence onto terrestrial environment at coastal regions. Wider coverage of spatial-temporal lacustrine sulfur geochemistry record is needed to validate the applicability of sulfur proxy in paleoenvironmental research. PMID:27941864

Mineral Trends in Early Hesperian Lacustrine Mudstone at Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Rampe, E. B.; Ming, D. W.; Grotzinger, J. P.; Morris, R. V.; Blake, D. F.; Vaniman, D. T.; Bristow, T. F.; Morrison, S. M.; Yen, A. S.; Chipera, S. J.;

Metal complexation capacity of Antarctic lacustrine sediments.

PubMed

Alberti, Giancarla; Mussi, Matteo; Quattrini, Federico; Pesavento, Maria; Biesuz, Raffaela

2018-04-01

The purpose of this study is to implement a work that is a part of a project funded by the Italian National Antarctic Research Program (PNRA, Piano Nazionale di Ricerche in Antartide) within the main thematic focus "Chemical Contamination-Global Change". This research was devoted to detect and characterize micro and nano components with strong complexing capability towards metal ions at trace level in sea water, lakes and lacustrine sediments, sampled during the XXII expedition of PNRA. In particular, in the present work, the sorption complexation capacity of an Antarctic lacustrine sediments toward Cu(II) and Pb(II) is described. The characterization of the sorption was undertaken, studying kinetics and isotherm profiles. The lake here considered is Tarn Flat in the area of Terra Nova Bay. The sorption equilibria of Cu(II) and Pb(II) on the lacustrine sediments were reached in about 10 h, and they were best modelled by the Langmuir equation. Preliminary, to establish if the data here obtained were consistent with those reported for the same area in other expeditions, a common multivariate techniques, namely the principal component analysis (PCA), was applied and finally the consistency of the data has been confirmed. Copyright © 2018 Elsevier Ltd. All rights reserved.

The Common Core of a Child Care Center. Child Care Facility Design.

ERIC Educational Resources Information Center

Moore, Gary T.

1997-01-01

Examines the notion of an early childhood education center organized as a series of houses around a common core of shared facilities. Discusses examples of child-care centers in Sweden and explores ideas that can promote functional facilities. Suggestions include ideas about physical-motor activities areas, administration offices, centralized…

Re–Os geochronology of the lacustrine Green River Formation: Insights into direct depositional dating of lacustrine successions, Re–Os systematics and paleocontinental weathering

USGS Publications Warehouse

Cumming, Vivien M.; Selby, David; Lillis, Paul G.

2012-01-01

Lacustrine sedimentary successions provide exceptionally high-resolution records of continental geological processes, responding to tectonic, climatic and magmatic influences. These successions are therefore essential for correlating geological and climatic phenomena across continents and furthermore the globe. Producing accurate geochronological frameworks within lacustrine strata is challenging because the stratigraphy is often bereft of biostratigraphy and directly dateable tuff horizons. The rhenium–osmium (Re–Os) geochronometer is a well-established tool for determining precise and accurate depositional ages of marine organic-rich rocks. Lake systems with stratified water columns are predisposed to the preservation of organic-rich rocks and thus should permit direct Re–Os geochronology of lacustrine strata. We present Re–Os systematics from one of the world's best documented lacustrine systems, the Eocene Green River Formation, providing accurate Re–Os depositional dates that are supported by Ar–Ar and U–Pb ages of intercalated tuff horizons. Precision of the Green River Formation Re–Os dates is controlled by the variation in initial 187Os/188Os and the range of 187Re/188Os ratios, as also documented in marine systems. Controls on uptake and fractionation of Re and Os are considered to relate mainly to depositional setting and the type of organic matter deposited, with the need to further understand the chelating precursors of Re and Os in organic matter highlighted. In addition to geochronology, the Re–Os data records the 187Os/188Os composition of lake water (1.41–1.54) at the time of deposition, giving an insight into continental runoff derived from weathering of the geological hinterland of the Green River Formation. Such insights enable us to evaluate fluctuations in continental climatic, tectonic and magmatic processes and provide the ability for chemostratigraphic correlation combined with direct depositional dates. Furthermore

Geochemical characteristics of Holocene laminated sapropel (unit II) and underlying lacustrine unit III in the Black Sea

USGS Publications Warehouse

Dean, Walter E.; Arthur, Michael A.

2011-01-01

eg 1 of the 1988 R/V Knorr expeditions to the Black Sea recovered 90 gravity and box cores. The longest recovery by gravity cores was about 3 meters, with an average of about 2.5 meters, recovering all of the Holocene and upper Pleistocene sections in the Black Sea. During the latest Pleistocene glaciation, sea level dropped below the 35-meters-deep Bosporus outlet sill of the Black Sea. Therefore throughout most of its history the Black Sea was a lake, and most of its sediments are lacustrine. The oldest sediments recovered (older than 8,000 calendar years) consist of massive to coarsely banded lacustrine calcareous clay designated as lithologic Unit III, generally containing less than 1 percent organic carbon (OC). The base of overlying Unit II marks the first incursion of Mediterranean seawater into the Black Sea, and the onset of bottom-water anoxia about 7,900 calendar years. Unit II contains as much as 15 percent OC in cores from the deepest part of the Black Sea (2,200 meters). The calcium carbonate (CaCO3) remains of the coccolith Emiliania huxleyi form the distinctive white laminae of overlying Unit I. The composition of Unit III and Unit II sediments are quite different, reflecting different terrigenous clastic sources and increased contributions from hydrogenous and biogenic components in anoxic Unit II sapropel. In Unit II, positive covariance between OC and three trace elements commonly concentrated in OC-rich sediments where sulfate reduction has occurred (molybdenum, nickel, and vanadium) and a nutrient (phosphorus) suggest a large marine source for these elements although nickel and vanadium also have a large terrigenous clastic source. The marine sources may be biogenic or hydrogenous. A large biogenic source is also suggested for copper and cobalt. Because abundant pyrite forms in the water column and sediments of the Black Sea, we expected to find a large hydrogenous iron component, but a strong covariance of iron with aluminum suggests that the

Challenges and Opportunities for Biological Mass Spectrometry Core Facilities in the Developing World.

PubMed

Bell, Liam; Calder, Bridget; Hiller, Reinhard; Klein, Ashwil; Soares, Nelson C; Stoychev, Stoyan H; Vorster, Barend C; Tabb, David L

2018-04-01

The developing world is seeing rapid growth in the availability of biological mass spectrometry (MS), particularly through core facilities. As proteomics and metabolomics becomes locally feasible for investigators in these nations, application areas associated with high burden in these nations, such as infectious disease, will see greatly increased research output. This article evaluates the rapid growth of MS in South Africa (currently approaching 20 laboratories) as a model for establishing MS core facilities in other nations of the developing world. Facilities should emphasize new services rather than new instruments. The reduction of the delays associated with reagent and other supply acquisition would benefit both facilities and the users who make use of their services. Instrument maintenance and repair, often mediated by an in-country business for an international vendor, is also likely to operate on a slower schedule than in the wealthiest nations. A key challenge to facilities in the developing world is educating potential facility users in how best to design experiments for proteomics and metabolomics, what reagents are most likely to introduce problematic artifacts, and how to interpret results from the facility. Here, we summarize the experience of 6 different institutions to raise the level of biological MS available to researchers in South Africa.

Bringing the Pieces Together – Placing Core Facilities at the Core of Universities and Institutions: Lessons from Mergers, Acquisitions and Consolidations

PubMed Central

Mundoma, Claudius

2013-01-01

As organizations expand and grow, the core facilities have become more dispersed disconnected. This is happening at a time when collaborations within the organization is a driver to increased productivity. Stakeholders are looking at the best way to bring the pieces together. It is inevitable that core facilities at universities and research institutes have to be integrated in order to streamline services and facilitate ease of collaboration. The path to integration often goes through consolidation, merging and shedding of redundant services. Managing this process requires a delicate coordination of two critical factors: the human (lab managers) factor and the physical assets factor. Traditionally more emphasis has been placed on reorganizing the physical assets without paying enough attention to the professionals who have been managing the assets for years, if not decades. The presentation focuses on how a systems approach can be used to effect a smooth core facility integration process. Managing the human element requires strengthening existing channels of communication and if necessary, creating new ones throughout the organization to break cultural and structural barriers. Managing the physical assets requires a complete asset audit and this requires direct input from the administration as well as the facility managers. Organizations can harness the power of IT to create asset visibility. Successfully managing the physical assets and the human assets increases productivity and efficiency within the organization.

Deformation of ``Villafranchian'' lacustrine sediments in the Chisone Valley (Western Alps, Italy)

NASA Astrophysics Data System (ADS)

Collo, Giovanni; Giardino, Marco

1997-09-01

The Chisone Valley is located in the internal NW Alps, in the Pinerolese District, an area characterized by present low to medium seismicity. Fine-grained sediments (sand, silt and clay with interbedded gravel) crop out in the lower Chisone Valley: they were first interpreted as glaciolacustrine deposits, and then as a lacustrine infilling of the valley floor probably due to differential uplifting of the valley mouth. Review of this data, together with new field and palynological observations, lead us to refer the lacustrine deposits to approximately the Lower Pleistocene (Villafranchian). In many outcrops, the lacustrine deposits show strong soft-sediment deformation such as convolute laminations, water-escape structures and disrupted beds, some of them associated with folds and faults (cm to dm in size); only two sites show metric to decametric folds and faults trending E-W and N-S. Detailed structural analysis conducted along a recently exposed section (Rio Gran Dubbione site) shows several soft-sediment deformation features on the limbs of mesoscale folds. Because of their intimate structural association, the origin of these minor structures seems to be connected to synsedimentary activity on reverse and normal faults (m to dm in size) affecting the lacustrine deposits in the same locality. Soft-sediment deformation features can be interpreted as possible paleoseismites. If so, the present seismicity of the Pinerolese District, which is the major area of such activity in NW Italy, cannot be considered an isolated episode in the geological evolution of the region; even if there is no supporting evidence for continuous seismicity, the deformations in the lacustrine sediments of the Chisone Valley testify to Early Pleistocene seismic activity, probably related to the recent tectonic evolution of the internal side of the NW Alps.

Are watershed and lacustrine controls on planktonic N2 fixation hierarchically structured?

PubMed

Scott, J Thad; Doyle, Robert D; Prochnow, Shane J; White, Joseph D

2008-04-01

N2 fixation can be an important source of N to limnetic ecosystems and can influence the structure of phytoplankton communities. However, watershed-scale conditions that favor N2 fixation in lakes and reservoirs have not been well studied. We measured N2 fixation and lacustrine variables monthly over a 19-month period in Waco Reservoir, Texas, USA, and linked these data with nutrient-loading estimates from a physically based watershed model. Readily available topographic, soil, land cover, effluent discharge, and climate data were used in the Soil and Water Assessment Tool (SWAT) to derive watershed nutrient-loading estimates. Categorical and regression tree (CART) analysis revealed that lacustrine and watershed correlates of N2 fixation were hierarchically structured. Lacustrine conditions showed greater predictive capability temporally. For instance, low NO3(-) concentration (<25 microg N/L) and high water temperatures (>27 degrees C) in the reservoir were correlated with the initiation of N2 fixation seasonally. When lacustrine conditions were favorable for N2 fixation, watershed conditions appeared to influence spatial patterns of N2 fixation within the reservoir. For example, spatially explicit patterns of N2 fixation were correlated with the ratio of N:P in nutrient loadings and the N loading rate, which were driven by anthropogenic activity in the watershed and periods of low stream flow, respectively. Although N2 fixation contributed <5% of the annual N load to the reservoir, 37% of the N load was derived from atmospheric N2 fixation during summertime when stream flow in the watershed was low. This study provides evidence that watershed anthropogenic activity can exert control on planktonic N2 fixation, but that temporality is controlled by lacustrine conditions. Furthermore, this study also supports suggestions that reduced inflows may increase the propensity of N2-fixing cyanobacterial blooms in receiving waters of anthropogenically modified landscapes.

Comparison of formation mechanism of fresh-water and salt-water lacustrine organic-rich shale

NASA Astrophysics Data System (ADS)

Lin, Senhu

2017-04-01

Based on the core and thin section observation, major, trace and rare earth elements test, carbon and oxygen isotopes content analysis and other geochemical methods, a detailed study was performed on formation mechanism of lacustrine organic-rich shale by taking the middle Permian salt-water shale in Zhungaer Basin and upper Triassic fresh-water shale in Ordos Basin as the research target. The results show that, the middle Permian salt-water shale was overall deposited in hot and dry climate. Long-term reductive environment and high biological abundance due to elevated temperature provides favorable conditions for formation and preservation of organic-rich shale. Within certain limits, the hotter climate, the organic-richer shale formed. These organic-rich shale was typically distributed in the area where palaeosalinity is relatively high. However, during the upper Triassic at Ordos Basin, organic-rich shale was formed in warm and moist environment. What's more, if the temperature, salinity or water depth rises, the TOC in shale decreases. In other words, relatively low temperature and salinity, stable lake level and strong reducing conditions benefits organic-rich shale deposits in fresh water. In this sense, looking for high-TOC shale in lacustrine basin needs to follow different rules depends on the palaeoclimate and palaeoenvironment during sedimentary period. There is reason to believe that the some other factors can also have significant impact on formation mechanism of organic-rich shale, which increases the complexity of shale oil and gas prediction.

The occurrence and transformation of lacustrine sediment gravity flow related to depositional variation and paleoclimate in the Lower Cretaceous Prosopis Formation of the Bongor Basin, Chad

NASA Astrophysics Data System (ADS)

Tan, Mingxuan; Zhu, Xiaomin; Geng, Mingyang; Zhu, Shifa; Liu, Wei

2017-10-01

Bed variability of sediment-gravity-flow deposits is quite prevalent in deep-marine settings, but it has not been well investigated in lacustrine settings. The depositional characteristics of various event beds are characterized in the North Slope Belt of the Bongor Basin (Chad), using detailed sedimentological, petrographic, geochemical as well as palynological analysis. Four bed types including classical turbidite bed, debrite bed, hybrid event bed, and hyperpycnite bed were distinguished based on their interpreted depositional processes. Variable mud contents of debrite beds and classic turbidite beds show distinct genetic characteristics in four core wells, whilst the high mud content of cohesive debrite interval and the low mud content of turbidite interval in hybrid event bed demonstrate the existence of flow transformation. Generally, several trace element and rare earth element proxy parameters show that these gravity-flow deposits of BS1-1 and D-3 cores are formed in more distal depositional settings than them of BN8 and BNE3 cores, which is also well consistent with sedimentological understandings achieved by seismic facies analysis. Although palynological results show a general hot arid climate during the deposition of the Prosopis Formation, but the climate-sensitive Sr/Cu ratio demonstrates that most sampled turbidite beds are postulated to be formed within a short humid pulse. The multi-approach analysis has illustrated that two potential forming mechanisms (delta-front-failure and flood-related origin) can be derived in different cored wells of such a small lacustrine rift basin. Differentiated flow transformation plays a significant role in the depositional characteristics and heterogenetic distribution of these event deposits.

Sedimentological reservoir characteristics of the Paleocene fluvial/lacustrine Yabus Sandstone, Melut Basin, Sudan

NASA Astrophysics Data System (ADS)

Mahgoub, M. I.; Padmanabhan, E.; Abdullatif, O. M.

2016-11-01

Melut Basin in Sudan is regionally linked to the Mesozoic-Cenozoic Central and Western African Rift System (CWARS). The Paleocene Yabus Formation is the main oil producing reservoir in the basin. It is dominated by channel sandstone and shales deposited in fluvial/lacustrine environment during the third phase of rifting in the basin. Different scales of sedimentological heterogeneities influenced reservoir quality and architecture. The cores and well logs analyses revealed seven lithofacies representing fluvial, deltaic and lacustrine depositional environments. The sandstone is medium to coarse-grained, poorly to moderately-sorted and sub-angular to sub-rounded, arkosic-subarkosic to sublitharenite. On the basin scale, the Yabus Formation showed variation in sandstone bodies, thickness, geometry and architecture. On macro-scale, reservoir quality varies vertically and laterally within Yabus Sandstone where it shows progressive fining upward tendencies with different degrees of connectivity. The lower part of the reservoir showed well-connected and amalgamated sandstone bodies, the middle to the upper parts, however, have moderate to low sandstone bodies' connectivity and amalgamation. On micro-scale, sandstone reservoir quality is directly affected by textures and diagenetic changes such as compaction, cementation, alteration, dissolution and kaolinite clays pore fill and coat all have significantly reduced the reservoir porosity and permeability. The estimated porosity in Yabus Formation ranges from 2 to 20% with an average of 12%; while permeability varies from 200 to 500 mD and up to 1 Darcy. The understanding of different scales of sedimentological reservoir heterogeneities might contribute to better reservoir quality prediction, architecture, consequently enhancing development and productivity.

Late Quaternary distal tephra-fall deposits in lacustrine sediments, Kenai Peninsula, Alaska

USGS Publications Warehouse

de Fontaine, C.S.; Kaufman, D.S.; Scott, Anderson R.; Werner, A.; Waythomas, C.F.; Brown, T.A.

2007-01-01

Tephra-fall deposits from Cook Inlet volcanoes were detected in sediment cores from Tustumena and Paradox Lakes, Kenai Peninsula, Alaska, using magnetic susceptibility and petrography. The ages of tephra layers were estimated using 21 14C ages on macrofossils. Tephras layers are typically fine, gray ash, 1-5??mm thick, and composed of varying proportions of glass shards, pumice, and glass-coated phenocrysts. Of the two lakes, Paradox Lake contained a higher frequency of tephra (0.8 tephra/100 yr; 109 over the 13,200-yr record). The unusually large number of tephra in this lake relative to others previously studied in the area is attributed to the lake's physiography, sedimentology, and limnology. The frequency of ash fall was not constant through the Holocene. In Paradox Lake, tephra layers are absent between ca. 800-2200, 3800-4800, and 9000-10,300??cal yr BP, despite continuously layered lacustrine sediment. In contrast, between 5000 and 9000??cal yr BP, an average of 1.7 tephra layers are present per 100 yr. The peak period of tephra fall (7000-9000??cal yr BP; 2.6 tephra/100 yr) in Paradox Lake is consistent with the increase in volcanism between 7000 and 9000 yr ago recorded in the Greenland ice cores. ?? 2007 Elsevier Inc. All rights reserved.

Formation of lacustrine plains in west-central Alaska as a result of permafrost degradation and aggradation

NASA Astrophysics Data System (ADS)

Kanevskiy, M. Z.; Jorgenson, M. T.; Shur, Y.; O'Donnell, J.; Harden, J. W.; Fortier, D.

2012-12-01

Perennially frozen lacustrine sediments containing a large amount of ground ice comprise a significant part of the upper permafrost of the lowlands of west-central Alaska, including Koyukuk Flats and Innoko Flats. Study sites are located in the discontinuous permafrost zone, where permafrost was encountered mainly within uplifted peat plateaus. The upper part of studied sections is formed by frozen peat up to 3 m thick underlain by lacustrine silt, which is mostly ice-rich. Cryogenic structure of lacustrine sediments at different sites has common features: (1) prevalence of layered, braided, and reticulate cryostructures; (2) high variability in the ice content of sediments; (3) high density and low water content of soil aggregates separated by ice lenses. Volume of visible ice in silt reaches at places 40% and more. The thickness of ice lenses generally varies from 1 to 5 cm and occasionally reaches 10 cm. Remnants of peat plateaus are surrounded by unfrozen bogs and fens, formed as a result of thawing and settling of ice-rich lacustrine silt. Modern thermokarst scars initially form at places where ice-rich silt is not protected by a thick layer of organic material. Further development of thermokarst bogs includes lateral enlargement of thaw bulbs and collapsing of the margins of peat plateaus. Lacustrine silt within taliks is covered by woody peat accumulated under forests during the stage of permafrost plateau formation and then by aquatic sphagnum peat accumulated in taliks after collapse. We relate the formation of ice-rich lacustrine sediments to development of lake thermokarst, which affected ice-rich silty yedoma deposits during the transition from Pleistocene to Holocene. Terrain development in lacustrine lowlands of west-central Alaska includes five stages related to permafrost aggradation and degradation from the late Pleistocene to the present time: 1) formation of the ice-rich syngenetic permafrost (yedoma) during the late Pleistocene; 2) yedoma

Small-scale lacustrine drifts in Lake Champlain, Vermont

USGS Publications Warehouse

Manley, Patricia L.; Manley, T.O.; Hayo, Kathryn; Cronin, Thomas

2012-01-01

High resolution CHIRP (Compressed High Intensity Radar Pulse) seismic profiles reveal the presence of two lacustrine sediment drifts located in Lake Champlain's Juniper Deep. Both drifts are positive features composed of highly laminated sediments. Drift B sits on a basement high while Drift A is built on a trough-filling acoustically-transparent sediment unit inferred to be a mass-transport event. These drifts are oriented approximately north–south and are parallel to a steep ridge along the eastern shore of the basin. Drift A, located at the bottom of a structural trough, is classified as a confined, elongate drift that transitions northward to become a system of upslope asymmetric mudwaves. Drift B is perched atop a structural high to the west of Drift A and is classified as a detached elongate drift. Bottom current depositional control was investigated using Acoustic Doppler Current Profilers (ADCPs) located across Drift A. Sediment cores were taken at the crest and at the edges of the Drift A and were dated. Drift source, deposition, and evolution show that these drifts are formed by a water column shear with the highest deposition occurring along its crest and western flank and began developing circa 8700–8800 year BP.

Volcanic influence of Mt. Fuji on the watershed of Lake Motosu and its impact on the lacustrine sedimentary record

NASA Astrophysics Data System (ADS)

Lamair, Laura; Hubert-Ferrari, Aurélia; Yamamoto, Shinya; El Ouahabi, Meriam; Vander Auwera, Jacqueline; Obrochta, Stephen; Boes, Evelien; Nakamura, Atsunori; Fujiwara, Osamu; Shishikura, Masanobu; Schmidt, Sabine; Siani, Giuseppe; Miyairi, Yosuke; Yokoyama, Yusuke; De Batist, Marc; Heyvaert, Vanessa M. A.; QuakeRecNankai Team

2018-01-01

Lacustrine sediments are particularly sensitive to modifications within the lake catchment. In a volcanic area, sedimentation rates are directly affected by the history of the volcano and its eruptions. Here, we investigate the impact of Mt. Fuji Volcano (Japan) on Lake Motosu and its watershed. The lacustrine infill is studied by combining seismic reflection profiles and sediment cores. We show evidence of changes in sedimentation patterns during the depositional history of Lake Motosu. The frequency of large mass-transport deposits recorded within the lake decreases over the Holocene. Before 8000 cal yr BP, large sublacustrine landslides and turbidites were filling the lacustrine depression. After 8000 cal yr BP, only one large sublacustrine landslide was recorded. The change in sedimentation pattern coincides with a change in sediment accumulation rate. Over the last 8000 cal yr BP, the sediment accumulation rate was not sufficient enough to produce large sublacustrine slope failures. Consequently, the frequency of large mass-transport deposits decreased and only turbidites resulting from surficial slope reworking occurred. These constitute the main sedimentary infill of the deep basin. We link the change in sediment accumulation rate with (i) climate and vegetation changes; and (ii) the Mt. Fuji eruptions which affected the Lake Motosu watershed by reducing its size and strongly modified its topography. Moreover, this study highlights that the deposition of turbidites in the deep basin of Lake Motosu is mainly controlled by the paleobathymetry of the lakefloor. Two large mass-transport deposits, occurring around 8000 cal yr BP and 2000 cal yr BP respectively, modified the paleobathymetry of the lakefloor and therefore changed the turbidite depositional pattern of Lake Motosu.

Late Cenozoic lacustrine and climatic environments at Tule Lake, northern Great Basin, USA

USGS Publications Warehouse

Platt, Bradbury J.

1992-01-01

Cores of lake sediment to a depth of 334 m in the town of Tulelake, Siskiyou County, northern California, document the late Cenozoic paleolimnologic and paleoclimatic history of the northwestern edge of the Great Basin. The cores have been dated by radiometric, tephrochronologic and paleomagnetic analyses. Lacustrine diatoms are abundant throughout the record and document a nearly continuous paleolimnologic history of the Tule Lake basin for the last 3 Myr. During most of this time, this basin (Tule Lake) was a relatively deep, extensive lake. Except for a drier (and cooler?) interval recorded by Fragilaria species about 2.4 Ma, the Pliocene is characterized by a dominance of planktonic Aulacoseira solida implying a warm monomictic lake under a climatic regime of low seasonality. Much of the Pleistocene is dominated by Stephanodiscus and Fragilaria species suggesting a cooler, often drier, and highly variable climate. Benthic diatoms typical of alkaline-enriched saline waters commonly appear after 1.0 Ma, and tephrochronology indicates slow deposition and possible hiatuses between about 0.6 and 0.2 Ma. The chronology of even-numbered oxygen isotope stages approximately matches fluctuations in the abundance of Fragilaria since 800 ka indicating that glacial periods were expressed as drier environments at Tule Lake. Glacial and interglacial environments since 150 ka were distinct from, and more variable than, those occurring earlier. The last full glacial period was very dry, but shortly thereafter Tule Lake became a deep, cool lacustrine system indicating a substantial increase in precipitation. Aulacoseira ambigua characterized the latest glacial and Holocene record of Tule Lake. Its distribution indicates that warmer and wetter climates began about 15 ka in this part of the Great Basin. Diatom concentration fluctuates at 41 000 year intervals between 3.0 and 2.5 Ma and at approximately 100 000 year intervals after 1.0 Ma. In the late Pliocene and early Pleistocene

Lacustrine records of Holocene climate and environmental change from the Lofoten Islands, Norway

NASA Astrophysics Data System (ADS)

Balascio, Nicholas L.

Lakes sediments from the Lofoten Islands, Norway, can be used to generate well resolved records of past climate and environmental change. This dissertation presents three lacustrine paleoenvironmental reconstructions that show evidence for Holocene climate changes associated with North Atlantic climate dynamics and relative sea-level variations driven by glacio-isostatic adjustment. This study also uses distal tephra deposits (cryptotephra) from Icelandic volcanic eruptions to improve the chronologies of these reconstructions and explores new approaches to crypto-tephrochronology. Past and present conditions at Vikjordvatnet, Fiskebolvatnet, and Heimerdalsvatnet were studied during four field seasons conducted from 2007--2010. Initially, each lake was characterized by measuring water column chemistry, logging annual temperature fluctuations, and conducting bathymetric and seismic surveys. Sediment cores were then collected and analyzed using multiple techniques, including: sediment density, magnetic susceptibility, loss-on-ignition, total carbon and nitrogen, delta13C and delta 15N of organic matter, and elemental compositions acquired by scanning X-ray fluorescence. Chronologies were established using radiocarbon dating and tephrochronology. A 13.8 cal ka BP record from Vikjordvatnet provides evidence for glacial activity during the Younger Dryas cold interval and exhibits trends in Ti, Fe, and organic content during the Holocene that correlate with regional millennial-scale climate trends and provide evidence for more rapid events. A 9.7 cal ka BP record from Fiskebolvatnet shows a strong signal of sediment inwashing likely driven by local geomorphic conditions, although there is evidence that increased inwashing at the onset of the Neoglacial could have been associated with increased precipitation. Heimerdalsvatnet provides a record of relative sea-level change. A 7.8 cal ka BP sedimentary record reflects changes in salinity and water column conditions as the

Summer temperatures inferred from varved lacustrine sediment at Iceberg Lake in southcentral Alaska

NASA Astrophysics Data System (ADS)

Diedrich, K.; Loso, M. G.

2010-12-01

Iceberg Lake, a glacier-dammed lake in southcentral Alaska, has been previously shown to record over 1,500 years of continuous laminated lacustrine sediment deposition. Because previous work was based on examination of subaerial outcrops exposed by stream incision in the bed of the jökulhlaup-drained lake, the length of the record was limited by the extent of the outcrops. In August of 2010, we returned to core the remote lake; our goal was recovery of the complete sedimentary record in the lake, extending perhaps back to the onset of late Holocene glaciation—around 3-5 ka in this region. We used a Vibarcorer system to recover sediment cores from two locations, one near the site of previous work and another at the distal end of the lake. The longest cores recovered were 5.2 meters and 6.2 meters at the proximal and distal sites, respectively. Based on the average lamination thickness established previously at the proximal site (4.7 mm), these cores should each represent over 1000 years of sediment accumulation, and likely much longer at the distal site, where laminations are expected to be thinner. Having established previously that the lake’s laminations are annual varves and that they are positively correlated with summer (melt-season) temperatures, our analysis is focused on documenting a long time-series of annual sediment accumulation and summer-layer particle size. Both measurements will be used to interpret the history of summer temperatures. The cores may also provide sedimentary evidence of the timing of advances/retreats of nearby glaciers, including the Tana Glacier and Bagley Icefield, helping to clarify the poorly-constrained timing of neoglaciation in Southern Alaska. The paleoclimate record produced at Iceberg Lake will be included in the Arctic System Science 8ka project

Luminescence dating of the lacustrine record of Vršac (Carpathian Basin, Serbia) - implications for a palaeoenvironmetal reconstruction

NASA Astrophysics Data System (ADS)

Klasen, N.; Zeeden, C.; Markovic, S.; Fischer, P.; Lehmkuhl, F.; Schulte, P.; Bösken, J.; Hambach, U.; Vött, A.

2017-12-01

The Carpathian Basin is one of the key areas to investigate the influence of the continental, Mediterranean and Atlantic climate interaction over Europe. The available Upper Pleistocene and Holocene geoarchives in the region are mainly loess-paleosol records. Long lacustrine records are sparse and do not always span the whole last glacial cycle. In the area around Vršac, we drilled a 10 m core to contribute to the palaeoenvironmental reconstruction of the Carpathian Basin. Electrical Resistivity Tomography (ERT) was used to find the best-suited drilling location. We applied luminescence and radiocarbon dating, because a robust chronology is important for the interpretation of the sedimentary record. Pulsed OSL measurements were carried out to identify the best sampling positions. We expect runoff from the catchment being the main source of the lacustrine sediments, because coarse fluvial input is absent. Knowledge about the depositional conditions is important in luminescence dating to evaluate partial bleaching prior to deposition, which may cause age overestimation. Therefore, we compared infrared stimulated luminescence (IRSL) signals with post infrared infrared stimulated luminescence (pIRIR) signals, which bleach at different rates. Estimation of a representative water content has major influence on the age estimate, but remains challenging in luminescence dating. We measured the present day water content as well as the saturation water content, to account for variations over time. Luminescence and radiocarbon ages differ greatly from each other. According to the laboratory experiments, luminescence dating was reliable and we conclude that radiocarbon ages were underestimated because of an intrusion of younger organic material. The initial results demonstrated the potential of the drill core. Integrating more proxy data will be useful to enhance the importance of the geoarchive at Vršac for a better understanding of the last glacial cycle in the Carpathian

Regional paleohydrologic and paleoclimatic settings of wetland/lacustrine depositional systems in the Morrison Formation (Upper Jurassic), Western Interior, USA

USGS Publications Warehouse

Dunagan, S.P.; Turner, C.E.

2004-01-01

During deposition of the Upper Jurassic Morrison Formation, water that originated as precipitation in uplands to the west of the Western Interior depositional basin infiltrated regional aquifers that underlay the basin. This regional groundwater system delivered water into the otherwise dry continental interior basin where it discharged to form two major wetland/lacustrine successions. A freshwater carbonate wetland/lacustrine succession formed in the distal reaches of the basin, where regional groundwater discharged into the Denver-Julesburg Basin, which was a smaller structural basin within the more extensive Western Interior depositional basin. An alkaline-saline wetland/lacustrine complex (Lake T'oo'dichi') formed farther upstream, where shallower aquifers discharged into the San Juan/Paradox Basin, which was another small structural basin in the Western Interior depositional basin. These were both wetlands in the sense that groundwater was the major source of water. Input from surface and meteoric water was limited. In both basins, lacustrine conditions developed during episodes of increased input of surface water. Inclusion of wetlands in our interpretation of what had previously been considered largely lacustrine systems has important implications for paleohydrology and paleoclimatology. The distal carbonate wetland/lacustrine deposits are well developed in the Morrison Formation of east-central Colorado, occupying a stratigraphic interval that is equivalent to the "lower" Morrison but extends into the "upper" Morrison Formation. Sedimentologic, paleontologic, and isotopic evidence indicate that regional groundwater discharge maintained shallow, hydrologically open, well oxygenated, perennial carbonate wetlands and lakes despite the semi-arid climate. Wetland deposits include charophyte-rich wackestone and green mudstone. Lacustrine episodes, in which surface water input was significant, were times of carbonate and siliciclastic deposition in scarce deltaic

Holocene glacier fluctuations inferred from lacustrine sediment, Emerald Lake, Kenai Peninsula, Alaska

NASA Astrophysics Data System (ADS)

LaBrecque, Taylor S.; Kaufman, Darrell S.

2016-01-01

Physical and biological characteristics of lacustrine sediment from Emerald Lake were used to reconstruct the Holocene glacier history of Grewingk Glacier, southern Alaska. Emerald Lake is an ice-marginal threshold lake, receiving glaciofluvial sediment when Grewingk Glacier overtops the topographic divide that separates it from the lake. Sub-bottom acoustical profiles were used to locate core sites to maximize both the length and resolution of the sedimentary sequence recovered in the 4-m-long cores. The age model for the composite sequence is based on 13 14C ages and a 210Pb profile. A sharp transition from the basal inorganic mud to organic-rich mud at 11.4 ± 0.2 ka marks the initial retreat of Grewingk Glacier below the divide of Emerald Lake. The overlaying organic-rich mud is interrupted by stony mud that records a re-advance between 10.7 ± 0.2 and 9.8 ± 0.2 ka. The glacier did not spill meltwater into the lake again until the Little Ice Age, consistent with previously documented Little Ice Ages advances on the Kenai Peninsula. The retreat of Grewingk Glacier at 11.4 ka took place as temperature increased following the Younger Dryas, and the subsequent re-advance corresponds with a climate reversal beginning around 11 ka across southern Alaska.

Sterols of a contemporary lacustrine sediment. [in English postglacial lake

NASA Technical Reports Server (NTRS)

Gaskell, S. J.; Eglinton, G.

1976-01-01

Results are reported for detailed sterol analyses of several depths (corresponding to between zero and about 150 yr in age) in a contemporary lacustrine sediment from a freshwater lake of postglacial origin in England. Delta 5-, delta 22-, and delta 5,22-sterols are identified along with 5 alpha- and 5 beta-stanols as well as a C26 stanol with a C7 side chain. Solvent extraction yields carbon number distributions for the 5 alpha- and 5 beta-stanol sediment constituents that parallel the corresponding delta 5-sterol distributions. The amounts of 5 alpha-stanols are found to exceed those of 5 beta-stanols in the sediment, and variations in the ratio of 5 alpha- to 5 beta-stanol between sediment samples from similar depths are shown to suggest an inhomogeneity of the sediment. It is found that the sterol composition of sediment cores varies markedly with depth, reflecting both the effects of a sterol hydrogenation process and a changing input to the sediment. It is concluded that C29 sterols, of probable higher-plant origin, predominate at lower sediment depths while C27 sterols, possibly derived from autochthonous sources, are more abundant in the surface sediment.

Carbon Cycle Dynamics through the Early Eocene Climatic Optimum: Orbital Couplings to Lacustrine Cycling

NASA Astrophysics Data System (ADS)

Rosengard, S. Z.; Grogan, D. S.; Whiteside, J. H.; van Keuren, M.; Musher, D.

2010-12-01

The early Eocene represents the most recent hothouse climate state of Earth history, a period during which Earth’s surface temperatures warmed and reached a steady peak at the Early Eocene Climatic Optimum (EECO), 53.5-50 Ma. Interspersed through the primary warming interval were several hyperthermals, or rapid peaks in surface temperature and pulses of carbon dioxide into the atmosphere, followed by rapid declines, lasting 10^4 to 10^5 years. Various hypotheses have been offered to explain the climatic triggers during the hothouse interval, including changes in ocean circulation, methane release from hydrates, volcanism, and turnover of terrestrial organic matter, implicating various couplings and feedbacks in the global carbon cycle. The present study investigates the prevailing changes in carbon cycle dynamics that occurred during a specific subinterval of the Early Eocene Climatic Optimum. We sampled a carbon-rich 300-ft ( 1100 kyr) section of lacustrine Green River Formation sediments from the TOSCO core in the Uinta Basin at a one-foot resolution for organic carbon content and δ^{13}C. The compiled data comprise a high-resolution profile of total organic carbon and isotopic organic carbon composition through the section, showing cyclic patterns that we hypothesize reflect orbital signals. Bulk isotopic carbon and shale oil measurements from an earlier Fischer Assay across TOSCO’s entire 1030-ft core were then filtered using the expected frequency of a 23-kyr precession cycle. The overlaid cycles reveal δ^{13}C and oil content to be anti-phase through the 300-ft section, except for an interval of 50 feet (180 kyr) from the Mahogany Zone to the B-groove of the core, where the two measurements are in-phase. Given that shale oil, a proxy for lake primary productivity and carbon burial, and δ^{13}C typically correlate inversely, this short, 180-kyr interval of in-phase variation suggests a significant alteration in the local carbon cycle. These preliminary

High-resolution δ13C record of fossil wood and bulk organic matter from a deep Oligocene lacustrine succession, Bach Long Vi Island, Vietnam

NASA Astrophysics Data System (ADS)

Rizzi, M.; Schovsbo, N. H.; Fyhn, M. B. W.; Korte, C.

2017-12-01

We present a high-resolution stable isotope record based on bulk organic matter (δ13Corg) and fossil wood (δ13Cwood) originating from Oligocene deep lacustrine sediments cored on the Bach Long Vi Island, northern Gulf of Tonkin, offshore Vietnam. The sediments are exceptionally well preserved. They are thus excellently suited for a detailed stratigraphical analysis of the stable isotope record and as proxy for environmental and climatic changes within this period. The sediments were deposited in rapid subsiding, narrow and elongated fault-bound graben (Fyhn and Phach, 2015) and are represented by deep pelagic lacustrine organic-rich mud interrupted by numerous density-flow deposits (Hovikoski et al., 2016). The density-flow deposits contain abundant fragments of fossil wood. Therefore it was possible to obtain 262 coalified wood fragments together with 1063 bulk organic samples throughout the span of the core. This allowed to establish a high resolution stable C isotope record (δ13Corg and δ13Cwood). In addition 2464 handheld XRF determinations were carried out to further characterize the depositional environment (Rizzi et al., 2017). The organic carbon isotope trend from the 500 m core succession provides insight into the palaeoenvironmental changes of the lake during the Oligocene. Both, global and local factors control the δ13C variations. The aim of the study is to obtain pure global δ13Corg and δ13Cwood signals that would allow comparison of the studied sediments with coeval syn-rift successions in the South China Sea region and other parts of the world. [1] Fyhn and Phach (2015) Tectonics, 34(2): 290-312. [2] Hovikoski et al. (2016) Journal of Sedimentary Research, 86(8): 982-1007. [3] Rizzi et al. (2017) EGU General Assembly Abstract EGU 2017-17584.

Spawning migration of lacustrine-adfluvial bull trout in a natural area

USGS Publications Warehouse

Brenkman, Samuel J.; Larson, Gary L.; Gresswell, Robert E.

2001-01-01

We investigated the spawning migration of lacustrine-adfluvial bull trout Salvelinus confluentus in the North Fork Skokomish River in Olympic National Park (Washington State) during 1996. Day-snorkeling and electrofishing were conducted to determine timing and duration of the migration and the distribution and abundance of bull trout. The primary spawning migration began in early October and was waning by December. Bull trout migrated 6 km or less up the river from Lake Cushman. Increased river discharge and decreased water temperature appeared to be the primary environmental variables corresponding to the initiation of the migration. Mean length of migratory bull trout increased from June to December. Comparisons with other lacustrine-adfluvial bull trout populations in Oregon, Montana, Idaho, and British Columbia suggested that these populations exhibit specific migratory strategies related to local environmental conditions.

Paleoenvironmental Interpretation of drill core from Tugen Hills, Kenya through X-ray Diffraction

NASA Astrophysics Data System (ADS)

Minkara, K. E.; Rabideaux, N. M.; Deocampo, D.; Kingston, J.; Cohen, A. S.

2016-12-01

Paleoenvironmental reconstruction in regions of significant archeological and paleontological discoveries can be used to help better understand early hominin history in relation to environmental changes. Using X-ray diffraction (XRD) analysis of lacustrine sediments obtained from core material recovered during the Hominin Sites and Paleolakes Drilling Project (HSPDP) campaign at the Tugen Hills drilling site in central Kenya we can reconstruct a high-resolution record of paleoclimate and tectonics from the lake sediments during the Plio-Pleistocene. XRD analysis enables us to identify the mineralogical trends from the 227m core, which can be employed to understand the geochemical evolution of the basin. We want to test whether 23-kyr precessional cyclicity is the primary driver of environmental change at Lake Baringo, and how that change influenced vertebrate and hominin evolution. Our goals are to understand how the paleolake geochemically evolved over time and how the mineralogical characteristics are related to climate change. Preliminary results indicate discrete zones of carbonate and zeolite mineral occurrence, suggesting possible paleoclimate indicators of humidity versus aridity. Geochemical and sedimentological analysis will be required to distinguish primary lacustrine carbonate versus secondary or pedogenic carbonate, which does not carry a lacustrine signal. Quartz-rich intervals and diatomaceous sequences are distinct from zeolitic zones, suggesting variable salinities. Furthermore, hkl reflections of clay-rich bulk samples suggest varying relative abundances of kaolinite and smectite. As we extract clay fractions and analyze the clay mineralogy in further detail, this ratio may provide an indicator of paleoweathering intensity within the basin.

Microbial community composition along a 50 000-year lacustrine sediment sequence

PubMed Central

Ariztegui, Daniel; Horn, Fabian; Kallmeyer, Jens; Orsi, William D

2018-01-01

Abstract For decades, microbial community composition in subseafloor sediments has been the focus of extensive studies. In deep lacustrine sediments, however, the taxonomic composition of microbial communities remains undercharacterized. Greater knowledge on microbial diversity in lacustrine sediments would improve our understanding of how environmental factors, and resulting selective pressures, shape subsurface biospheres in marine and freshwater sediments. Using high-throughput sequencing of 16S rRNA genes across high-resolution climate intervals covering the last 50 000 years in Laguna Potrok Aike, Argentina, we identified changes in microbial populations in response to both past environmental conditions and geochemical changes of the sediment during burial. Microbial communities in Holocene sediments were most diverse, reflecting a layering of taxa linked to electron acceptors availability. In deeper intervals, the data show that salinity, organic matter and the depositional conditions over the Last Glacial-interglacial cycle were all selective pressures in the deep lacustrine assemblage resulting in a genetically distinct biosphere from the surface dominated primarily by Bathyarchaeota and Atribacteria groups. However, similar to marine sediments, some dominant taxa in the shallow subsurface persisted into the subsurface as minor fraction of the community. The subsequent establishment of a deep subsurface community likely results from a combination of paleoenvironmental factors that have shaped the pool of available substrates, together with substrate depletion and/or reworking of organic matter with depth. PMID:29471361

Lacustrine Environment Reservoir Properties on Sandstone Minerals and Hydrocarbon Content: A Case Study on Doba Basin, Southern Chad

NASA Astrophysics Data System (ADS)

Sumery, N. F. Mohd; Lo, S. Z.; Salim, A. M. A.

2017-10-01

The contribution of lacustrine environment as the hydrocarbon reservoir has been widely known. However, despite its growing importance, the lacustrine petroleum geology has received far less attention than marine due to its sedimentological complexity. This study therefore aims in developing an understanding of the unique aspects of lacustrine reservoirs which eventually impacts the future exploration decisions. Hydrocarbon production in Doba Basin, particularly the northern boundary, for instance, has not yet succeeded due to the unawareness of its depositional environment. The drilling results show that the problems were due to the: radioactive sand and waxy oil/formation damage, which all are related to the lacustrine depositional environment. Detailed study of geological and petrophysical integration on wireline logs and petrographic thin sections analysis of this environment helps in distinguishing reservoir and non-reservoir areas and determining the possible mechanism causing the failed DST results. The interpretations show that the correlation of all types> of logs and rho matrix analysis are capable in identifying sand and shale bed despite of the radioactive sand present. The failure of DST results were due to the presence of arkose in sand and waxy oil in reservoir bed. This had been confirmed by the petrographic thin section analysis where the arkose has mineral twinning effect indicate feldspar and waxy oil showing bright colour under fluorescent light. Understanding these special lacustrine environment characteristics and features will lead to a better interpretation of hydrocarbon prospectivity for future exploration.

Organic sedimentation in modern lacustrine systems: A case study from Lake Malawi, East Africa

USGS Publications Warehouse

Ellis, Geoffrey S.; Barry J. Katz,; Christopher A. Scholz,; Peter K. Swart,

2015-01-01

This study examines the relationship between depositional environment and sedimentary organic geochemistry in Lake Malawi, East Africa, and evaluates the relative significance of the various processes that control sedimentary organic matter (OM) in lacustrine systems. Total organic carbon (TOC) concentrations in recent sediments from Lake Malawi range from 0.01 to 8.80 wt% and average 2.83 wt% for surface sediments and 2.35 wt% for shallow core sediments. Hydrogen index (HI) values as determined by Rock-Eval pyrolysis range from 0 to 756 mg HC g−1 TOC and average 205 mg HC g−1 TOC for surface sediments and 228 mg HC g−1 TOC for shallow core samples. On average, variations in primary productivity throughout the lake may account for ~33% of the TOC content in Lake Malawi sediments (as much as 1 wt% TOC), and have little or no impact on sedimentary HI values. Similarly, ~33% to 66% of the variation in TOC content in Lake Malawi sediments appears to be controlled by anoxic preservation of OM (~1–2 wt% TOC), although some component of the water depth–TOC relationship may be due to physical sediment transport processes. Furthermore, anoxic preservation has a minimal effect on HI values in Lake Malawi sediments. Dilution of OM by inorganic sediment may account for ~16% of variability in TOC content in Lake Malawi sediments (~0.5 wt% TOC). The effect of inputs of terrestrial sediment on the organic character of surface sediments in these lakes is highly variable, and appears to be more closely related to the local depositional environment than the regional flux of terrestrial OM. Total nitrogen and TOC content in surface sediments collected throughout the lake are found to be highly correlated (r2 = 0.95), indicating a well-homogenized source of OM to the lake bottom. The recurring suspension and deposition of terrestrial sediment may account for significant amounts of OM deposited in offshore regions of the lake. This process effectively separates denser

Improving age-depth models using sedimentary proxies for accumulation rates in fluvio-lacustrine deposits

NASA Astrophysics Data System (ADS)

Minderhoud, Philip S. J.; Cohen, Kim M.; Toonen, Willem. H. J.; Erkens, Gilles; Hoek, Wim Z.

2017-04-01

Lacustrine fills, including those of oxbow lakes in river floodplains, often hold valuable sedimentary and biological proxy records of palaeo-environmental change. Precise dating of accumulated sediments at levels throughout these records is crucial for interpretation and correlation of (proxy) data existing within the fills. Typically, dates are gathered from multiple sampled levels and their results are combined in age-depth models to estimate the ages of events identified between the datings. In this paper, a method of age-depth modelling is presented that varies the vertical accumulation rate of the lake fill based on continuous sedimentary data. In between Bayesian calibrated radiocarbon dates, this produces a modified non-linear age-depth relation based on sedimentology rather than linear or spline interpolation. The method is showcased on a core of an infilled palaeomeander at the floodplain edge of the river Rhine near Rheinberg (Germany). The sequence spans from 4.7 to 2.9 ka cal BP and consists of 5.5 meters of laminated lacustrine, organo-clastic mud, covered by 1 meter of peaty clay. Four radiocarbon dates provide direct dating control, mapping and dating in the wider surroundings provide additional control. The laminated, organo-clastic facies of the oxbow fill contains a record of nearby fluvial-geomorphological activity, including meander reconfiguration events and passage of rare large floods, recognized as fluctuations in coarseness and amount of allochthonous clastic sediment input. Continuous along-core sampling and measurement of loss-on-ignition (LOI) provided a fast way of expressing the variation in clastic sedimentation influx from the nearby river versus autochthonous organic deposition derived from biogenic production in the lake itself. This low-cost sedimentary proxy data feeds into the age-depth modelling. The sedimentology-modelled age-depth relation (re)produces the distinct lithological boundaries in the fill as marked changes in

Hydroecology of Amazonian lacustrine Arcellinida (testate amoebae): A case study from Lake Quistococha, Peru.

PubMed

Patterson, R Timothy; Huckerby, Gail; Kelly, Thomas J; Swindles, Graeme T; Nasser, Nawaf A

2015-10-01

Organic rich sediments were obtained from seven core tops taken in Lake Quistococha, near the city of Iquitos in the Peruvian Amazon. Subsamples from 0 to 4cm depth in each core were analyzed under dissecting light microscopy to carry out the first investigation of Arcellinida (testate lobose amoebae) from a lacustrine environment in this ecologically important region. The fauna was characterized by a low diversity, low abundance community dominated by centropyxids. This fauna is similar to 'stressed' assemblages reported from temperate latitudes, except that test concentrations were two orders of magnitude lower than typical in temperate lakes. Principle arcellinidan stressors in Lake Quistococha likely include the low pH 4 conditions in the lake, and a general lack of suitable minerogenic material to construct tests in the organic rich lake substrate. The low pH conditions are the result of runoff and seepage of water high in dissolved organic carbon from the adjacent similarly low pH 4 terrestrial peatland. The dearth of minerogenic material is the result of the lake being isolated from riverine input for the past ∼2000 years, even during flooding events. Other limiting factors contributing to depressed arcellinidan populations may include nutrient supply, predation pressure, competition, and post-mortem taphonomic factors. Copyright © 2015 Elsevier GmbH. All rights reserved.

Dose and Dose Risk Caused by Natural Phenomena - Proposed Powder Metallurgy Core Manufacturing Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmes, W.G.

2001-08-16

The offsite radiological effects from high velocity straight winds, tornadoes, and earthquakes have been estimated for a proposed facility for manufacturing enriched uranium fuel cores by powder metallurgy. Projected doses range up to 30 mrem/event to the maximum offsite individual for high winds and up to 85 mrem/event for very severe earthquakes. Even under conservative assumptions on meteorological conditions, the maximum offsite dose would be about 20 per cent of the DOE limit for accidents involving enriched uranium storage facilities. The total dose risk is low and is dominated by the risk from earthquakes. This report discusses this test.

Estimation of the tectonic slip-rate from Quaternary lacustrine facies within the intraplate Albacete province (SE of Spain)

USGS Publications Warehouse

Rodriguez-Pascua, M. A.; Bischoff, J.; Garduno-Monroy, Victor H.; Pérez-López, R.; Giner-Robles, J.L.; Israde-Alcántara, I.; Calvo, J.P.; Williams, Ross W.

2009-01-01

The Quaternary lacustrine basin of Cordovilla (CB) represents one of the most active tectonic areas of the Prebetic Zone (Albacete, SE of Spain). The Quaternary sedimentary deposits of this basin are mainly endoreic lacustrine carbonate and alluvial deposits, developed in a semi-arid climate (Pleistocene-present). The basin is a NW-SE-elongated graben bounded by a major right-lateral oblique-fault, the Pozohondo Fault. This fault trends NW-SE, with an approximate trace of 55 km, and is composed of various segments which are identified by fault scarps. In order to establish the slip-rate of the most active segment of the Pozohondo Fault, called the Cordovilla segment, we carried out a detailed study of the affected Quaternary lacustrine deposits. We found that the lacustrine facies could be related to episodic moderate paleoearthquakes. The slip-rate is calculated to be 0.05 and 0.09 mm/yr, using radiometric dating for the vertical offsets of the lacustrine facies. A trenching study at the northern part of the Cordovilla segment revealed two events caused by paleoearthquakes, with the most recent expressed as an oblique-fault off-setting a poorly-developed soil. The magnitude of the last event was greater than 6, using various empirical relationships for the fault displacement and the surface-length rupture. We estimate episodic activity across the Cordovilla segment, to be characterized by moderate-sized paleoearthquakes (M6), which is in agreement with the tectonic context of an intraplate zone of the Iberian plate. ?? 2009 Elsevier B.V.

Chapter D: With or Without Salt-a Comparison of Marine and Continental-Lacustrine Diatomite Deposits

USGS Publications Warehouse

Moyle, Phillip R.; Dolley, Thomas P.

2003-01-01

Diatoms in sedimentary deposits of marine and continental, especially lacustrine, origin have similar nutrient (for example, phosphate, nitrate, and silica) and light requirements; however, their geologic ranges and physiographic environments vary. Marine diatoms range in age from Early Cretaceous to Holocene, and continental diatoms range in age from Eocene to Holocene; however, most commercial diatomites, both marine and lacustrine, were deposited during the Miocene. Marine deposits of commercial value generally accumulated along continental margins with submerged coastal basins and shelves where wind-driven boundary currents provided the nutrient-rich upwelling conditions capable of supporting a productive diatom habitat. Commercial freshwater diatomite deposits occur in volcanic terrains associated with events that formed sediment-starved drainage basins, such as the Basin and Range Province, particularly in Nevada. Marine habitats generally are characterized by stable conditions of temperature, salinity, pH, nutrients, and water currents, in contrast to lacustrine habitats, which are characterized by wide variations in these conditions. Marine deposits generally are of higher quality and contain larger resources, owing to their greater areal extent and thickness, whereas most of the world's known diatomites are of lacustrine origin. Both types of deposit are commonly mined by open-pit methods and subjected to processing designed to remove organic matter, CO2, pore water, and inorganic contaminants in order to produce purified products. The highest quality diatomites, predominantly from marine sources, are used in filtration, although both types of deposit produce filter grades, and additional end uses include fillers, additives, absorbents, and abrasives.

A High-Throughput Biological Calorimetry Core: Steps to Startup, Run, and Maintain a Multiuser Facility.

PubMed

Yennawar, Neela H; Fecko, Julia A; Showalter, Scott A; Bevilacqua, Philip C

2016-01-01

Many labs have conventional calorimeters where denaturation and binding experiments are setup and run one at a time. While these systems are highly informative to biopolymer folding and ligand interaction, they require considerable manual intervention for cleaning and setup. As such, the throughput for such setups is limited typically to a few runs a day. With a large number of experimental parameters to explore including different buffers, macromolecule concentrations, temperatures, ligands, mutants, controls, replicates, and instrument tests, the need for high-throughput automated calorimeters is on the rise. Lower sample volume requirements and reduced user intervention time compared to the manual instruments have improved turnover of calorimetry experiments in a high-throughput format where 25 or more runs can be conducted per day. The cost and efforts to maintain high-throughput equipment typically demands that these instruments be housed in a multiuser core facility. We describe here the steps taken to successfully start and run an automated biological calorimetry facility at Pennsylvania State University. Scientists from various departments at Penn State including Chemistry, Biochemistry and Molecular Biology, Bioengineering, Biology, Food Science, and Chemical Engineering are benefiting from this core facility. Samples studied include proteins, nucleic acids, sugars, lipids, synthetic polymers, small molecules, natural products, and virus capsids. This facility has led to higher throughput of data, which has been leveraged into grant support, attracting new faculty hire and has led to some exciting publications. © 2016 Elsevier Inc. All rights reserved.

Sources of core and intact branched tetraether membrane lipids in the lacustrine environment: Anatomy of Lake Challa and its catchment, equatorial East Africa

NASA Astrophysics Data System (ADS)

Buckles, Laura K.; Weijers, Johan W. H.; Verschuren, Dirk; Sinninghe Damsté, Jaap S.

2014-09-01

The MBT/CBT palaeotemperature proxy uses the distribution of branched glycerol dialkyl glycerol tetraethers (brGDGTs), membrane lipids that are supposed to derive from soil bacteria, to reconstruct mean annual air temperature (MAAT). Applied successfully in coastal marine sediments, its extension to lake-sediment records with potentially high time resolution would greatly expand its utility. Over the last years, however, studies have indicated the presence of additional sources of brGDGTs within lake systems. To constrain the factors influencing the MBT/CBT palaeotemperature proxy in lakes, detailed investigation of brGDGT fluxes in a modern lake system is necessary to identify their potential sources. This study concentrates on Lake Challa, a permanently stratified crater lake in equatorial East Africa with limited catchment area. An almost 3-year time series of approximately monthly samples of settling particles, supplemented with a depth profile of suspended particulate matter (SPM) and sets of profundal surface-sediment and catchment soil samples, were analysed for both the 'living' intact polar lipids (IPLs) and 'fossil' core lipids (CLs) of GDGTs. We found that brGDGTs are produced in oxic, suboxic and anoxic zones of the water column, and in substantial amounts compared to influxes from catchment soils. Additional in situ production within the lake sediments is most probable, but cannot be definitely confirmed at this time. These lacustrine brGDGTs display a different response to temperature variation than soil-derived brGDGTs, signifying either a different physiological adaptation to changing conditions within the water column and/or a different composition of the respective bacterial communities. Using this specific relationship with temperature, a local calibration based on brGDGT distributions in SPM generates relatively accurate water temperature estimates from settling particles but fails for surface sediments.

Palaeogeographic, palaeoclimatic, palaeohydrological and chemical/biochemical controls on accumulation of late Eocene coastal lacustrine-palustrine limestones, Southern England

NASA Astrophysics Data System (ADS)

Armenteros, Ildefonso; Edwards, Nicholas

2012-12-01

The shallow-lacustrine to palustrine Hatherwood Limestone Member of the late Eocene Headon Hill Formation, Southern England, is in a succession of fluvio-estuarine and laguno-lacustrine siliciclastic sediments. It is up to 8.0 m thick and is subdivided by metric-scale palaeotopographic erosion surfaces, one of which underlies lenticular humic siliciclastic mudstones. The limestone lithologies are (1) biocalcilutites/biocalcisiltites, (2) biocalcarenites, (3) calcirudites, and (4) laterally-discontinuous laminar and fenestral crusts. Lithology (1) accumulated in a low-energy shallow-lacustrine depositional environment, indicated by the predominance of pulmonate pond-snails in the mollusc assemblage. In contrast, lithologies (2) and (3) are the coarse-grained fills of shallow palaeotopographic lows, and also form basal lags and palaeokarst-fills. Lithology (3) comprises remnant autochthonous lags that resulted from selective erosion during lacustrine transgressions. Brecciation and proto-intraclast to nodular differentiation in lithology (2) suggests derivation of the intraclasts from subaerially- and pedogenically-modified shallow-lacustrine muds. Laminar crusts (4), 0.5-6.0 cm in thickness, display irregularly undulose and anastamosing laminations 150-400 μm thick, that display differential staining by iron oxide. The abundance of rootlet traces and calcitised parenchymatic root tissues in the fenestral crusts suggests a palustrine depositional environment for these lithologies. The siliciclastic mudstone lithologies are (1) black humic muds and (2) blue-green silty muds and marls. The high C/N molar ratio of the black muds suggests derivation of the humic content mainly from vascular plants in local wetlands. The mollusc assemblage of the blue-green siliciclastic muds resembles floodplain lake assemblages from the regional Palaeogene succession. Mean stable isotopic values for limestone samples, of - 4.75 ± 1.53 for δ13C and - 2.77 ± 1.47 for δ18O, indicate a

Age model for a continuous, ca 250-ka Quaternary lacustrine record from Bear Lake, Utah-Idaho

USGS Publications Warehouse

Colman, Steven M.; Kaufman, D.S.; Bright, Jordon; Heil, C.; King, J.W.; Dean, W.E.; Rosenbaum, J.G.; Forester, R.M.; Bischoff, J.L.; Perkins, Marie; McGeehin, J.P.

2006-01-01

The Quaternary sediments sampled by continuous 120-m-long drill cores from Bear Lake (Utah-Idaho) comprise one of the longest lacustrine sequences recovered from an extant lake. The cores serve as a good case study for the construction of an age model for sequences that extend beyond the range of radiocarbon dating. From a variety of potential age indicators, we selected a combination of radiocarbon ages, one magnetic excursion (correlated to a standard sequence), and a single Uranium-series age to develop an initial data set. The reliability of the excursion and U-series data require consideration of their position with respect to sediments of inferred interglacial character, but not direct correlation with other paleoclimate records. Data omitted from the age model include amino acid age estimates, which have a large amount of scatter, and tephrochronology correlations, which have relatively large uncertainties. Because the initial data set was restricted to the upper half of the BL00-1 core, we inferred additional ages by direct correlation to the independently dated paleoclimate record from Devils Hole. We developed an age model for the entire core using statistical methods that consider both the uncertainties of the original data and that of the curve-fitting process, with a combination of our initial data set and the climate correlations as control points. This age model represents our best estimate of the chronology of deposition in Bear Lake. Because the age model contains assumptions about the correlation of Bear Lake to other climate records, the model cannot be used to address some paleoclimate questions, such as phase relationships with other areas.

High resolution HH-XRF scanning and XRD modelling as a tool in sedimentological analysis - A case study from the Enreca-3 core, Bach Long Vi Island, Vietnam

NASA Astrophysics Data System (ADS)

Rizzi, Malgorzata; Hemmingsen Schovsbo, Niels; Korte, Christoph; Bryld Wessel Fyhn, Michael

2017-04-01

To improve the understanding and interpretation of the depositional environment of a late Oligocene lacustrine organic rich oil-prone source rock succession, 2464 hand held (HH)-XRF measurements were made systematically on the 500 m long, continuous core from the fully cored Enreca-3 well. This core, drilled on the remote Bach Long Vi Island, northern Gulf of Tonkin, offshore Vietnam, represents a deep lake succession alternating between lacustrine pelagic dominated sediments interrupted by hyperpycnal turbidites, high density turbidites and debris flows [1, 2]. From a combined HH-XRF-XRD data set, multivariate data analysis and regression models are used to type the rock and to predict the XRD mineral composition based on HH-XRF composition. The rock types and the modelled mineral composition highlight the geochemical variations of the sediment and allows for direct comparison with sedimentological processes and facies changes. The modeling also depicts the cyclic alteration of rock types that are present on many different scales ranging from centimeters to hundreds of meters [1, 2]. The sedimentological and geochemical variations observed throughout the cored section reflects fluctuating paleoclimate, tectonism and hinterland condition controlling the depositional setting, which may provide a deeper understanding of the deposition of this and similar Paleogene syn-rift succession in the South China Sea region. It allows furthermore the development of a more generalized depositional model relevant for other deep-lacustrine syn-rift basins. [1] Petersen et al. (2014) Journal of Petroleum Geology, 37: 373-389. [2] Hovikoski et al. (2016) Journal of Sedimentary Research, 86(8): 982-1007.

Mineralogy of Mudstone at Gale Crater, Mars: Evidence for Dynamic Lacustrine Environments

NASA Technical Reports Server (NTRS)

Rampe, E. B.; Ming, D. W.; Grotzinger, J. P.; Morris, R. V.; Blake, D. F.; Vaniman, D. T.; Bristow, T. F.; Yen, A. S.; Chipera, S. J.; Morrison, S. M.;

Updated procedures for using drill cores and cuttings at the Lithologic Core Storage Library, Idaho National Laboratory, Idaho

USGS Publications Warehouse

Hodges, Mary K.V.; Davis, Linda C.; Bartholomay, Roy C.

2018-01-30

In 1990, the U.S. Geological Survey, in cooperation with the U.S. Department of Energy Idaho Operations Office, established the Lithologic Core Storage Library at the Idaho National Laboratory (INL). The facility was established to consolidate, catalog, and permanently store nonradioactive drill cores and cuttings from subsurface investigations conducted at the INL, and to provide a location for researchers to examine, sample, and test these materials.The facility is open by appointment to researchers for examination, sampling, and testing of cores and cuttings. This report describes the facility and cores and cuttings stored at the facility. Descriptions of cores and cuttings include the corehole names, corehole locations, and depth intervals available.Most cores and cuttings stored at the facility were drilled at or near the INL, on the eastern Snake River Plain; however, two cores drilled on the western Snake River Plain are stored for comparative studies. Basalt, rhyolite, sedimentary interbeds, and surficial sediments compose most cores and cuttings, most of which are continuous from land surface to their total depth. The deepest continuously drilled core stored at the facility was drilled to 5,000 feet below land surface. This report describes procedures and researchers' responsibilities for access to the facility and for examination, sampling, and return of materials.

Discovery of silicified lacustrine micro-fossils and stromatolites: Triassic-Jurassic Fundy Group, Nova Scotia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron, B.

A unique assemblage of silicified invertebrate and algal fresh-water lake fossils has been discovered in the Scots Bay Formation at the top of the Triassic-Jurassic Fundy Group of the Fundy Basin in Nova Scotia. This is important because the basins of the eastern North American Triassic-Jurassic rift system have not yielded many invertebrate and algal fossils. These new finds will contribute significantly to evolutionary, paleoecological and biostratigraphic studies of fresh-water Mesozoic deposits. Silicified fossils have been extracted from chert-bearing, mixed carbonate and siliciclastic lithologies. They include ostracodes, gastropods, rare bivalves, charaphytes (algae), stromatolites, and chert nodules cored with well-preserved woodymore » tissues of tree trunks. Possible algal filaments occur in the silicified stromatolites. This association of charaphytes, ostracodes, microscopic gastropods and stromatolites is found in carbonate lakes today. The Scots Bay Formation is probably a near-shore carbonate facies of the more widespread silicilastic lacustrine McCoy Brook Formation. The gastropods and ostracodes, studied by SEM, indicate a Jurassic age for the Scots bay Formation, confirming speculations based on other data.« less

Volcanogenic Fluvial-Lacustrine Environments in Iceland and Their Utility for Identifying Past Habitability on Mars

PubMed Central

Cousins, Claire

2015-01-01

The search for once-habitable locations on Mars is increasingly focused on environments dominated by fluvial and lacustrine processes, such as those investigated by the Mars Science Laboratory Curiosity rover. The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures. Fluvial-lacustrine environments associated with basaltic volcanism are highly relevant to Mars, but their terrestrial counterparts have been largely overlooked as a field analogue. Such environments are common in Iceland, where basaltic volcanism interacts with glacial ice and surface snow to produce large volumes of meltwater within an otherwise cold and dry environment. This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems. Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides). This paper reviews examples of these environments, including their sedimentary deposits and microbiology, within the context of utilising these localities for future Mars analogue studies and instrument testing. PMID:25692905

Volcanogenic fluvial-lacustrine environments in iceland and their utility for identifying past habitability on Mars.

PubMed

Cousins, Claire

2015-02-16

The search for once-habitable locations on Mars is increasingly focused on environments dominated by fluvial and lacustrine processes, such as those investigated by the Mars Science Laboratory Curiosity rover. The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures. Fluvial-lacustrine environments associated with basaltic volcanism are highly relevant to Mars, but their terrestrial counterparts have been largely overlooked as a field analogue. Such environments are common in Iceland, where basaltic volcanism interacts with glacial ice and surface snow to produce large volumes of meltwater within an otherwise cold and dry environment. This meltwater can be stored to create subglacial, englacial, and proglacial lakes, or be released as catastrophic floods and proglacial fluvial systems. Sedimentary deposits produced by the resulting fluvial-lacustrine activity are extensive, with lithologies dominated by basaltic minerals, low-temperature alteration assemblages (e.g., smectite clays, calcite), and amorphous, poorly crystalline phases (basaltic glass, palagonite, nanophase iron oxides). This paper reviews examples of these environments, including their sedimentary deposits and microbiology, within the context of utilising these localities for future Mars analogue studies and instrument testing.

Nanoscale semiconductor-insulator-metal core/shell heterostructures: facile synthesis and light emission

NASA Astrophysics Data System (ADS)

Li, Gong Ping; Chen, Rui; Guo, Dong Lai; Wong, Lai Mun; Wang, Shi Jie; Sun, Han Dong; Wu, Tom

2011-08-01

Controllably constructing hierarchical nanostructures with distinct components and designed architectures is an important theme of research in nanoscience, entailing novel but reliable approaches of bottom-up synthesis. Here, we report a facile method to reproducibly create semiconductor-insulator-metal core/shell nanostructures, which involves first coating uniform MgO shells onto metal oxide nanostructures in solution and then decorating them with Au nanoparticles. The semiconductor nanowire core can be almost any material and, herein, ZnO, SnO2 and In2O3 are used as examples. We also show that linear chains of short ZnO nanorods embedded in MgO nanotubes and porous MgO nanotubes can be obtained by taking advantage of the reduced thermal stability of the ZnO core. Furthermore, after MgO shell-coating and the appropriate annealing treatment, the intensity of the ZnO near-band-edge UV emission becomes much stronger, showing a 25-fold enhancement. The intensity ratio of the UV/visible emission can be increased further by decorating the surface of the ZnO/MgO nanowires with high-density plasmonic Au nanoparticles. These heterostructured semiconductor-insulator-metal nanowires with tailored morphologies and enhanced functionalities have great potential for use as nanoscale building blocks in photonic and electronic applications.Controllably constructing hierarchical nanostructures with distinct components and designed architectures is an important theme of research in nanoscience, entailing novel but reliable approaches of bottom-up synthesis. Here, we report a facile method to reproducibly create semiconductor-insulator-metal core/shell nanostructures, which involves first coating uniform MgO shells onto metal oxide nanostructures in solution and then decorating them with Au nanoparticles. The semiconductor nanowire core can be almost any material and, herein, ZnO, SnO2 and In2O3 are used as examples. We also show that linear chains of short ZnO nanorods embedded in

Diagenetic effects on magnetic minerals in a Holocene lacustrine sediment core from Huguangyan maar lake, southeast China

NASA Astrophysics Data System (ADS)

Wu, Xudong; Wang, Yong; Bian, Liu; Shen, Ji

2016-09-01

Post-depositional reductive diagenesis usually results in partial or entire cleansing of the pristine palaeomagnetic signal, therefore, its intensity is important to be assessed for sediments that are in the purpose of retrieving palaeomagnetic information. Grain size, rock magnetic and geochemical studies on the entire core, along with scanning electron microscope observations and X-ray diffraction analyses for representative samples were carried out on a Holocene sediment core retrieved from the deep water part of Huguangyan maar lake (HGY), southeast China. The pristine magnetic mineral assemblage of the studied core is domianted by superparamagnetic (SP) and stable single domain titanomagnetite, and high coercivity minerals are not detectable. Based on down-core variations of the average grain size (MZ), total organic carbon (TOC), detrital elements (Al, Ti, Fe and Mn) and the concentration and mineralogy of magnetic minerals, the studied core could be divided into three subsections. The uppermost subsection is the least affected by diagenesis, with detrital titanomagnetite as the dominant magnetic mineral. This is owing to low TOC contents, but high detrital input generated by weak Asian summer monsoon intensity during the late Holocene. The intermediate subsection shows down-core progressively enhanced dissolution of detrital titanomagnetite, and concomitant formation of authigenic pyrite and siderite, which indicates down-core progressively enhanced diagenesis generated by down-core progressive increasing TOC content, but decreasing detrital input as the result of down-core progressively strengthened Asian summer monsoon intensity. The pristine magnetic mineral assemblage has been profoundly modified in the lowermost subsection. At certain positions of the lowermost subsection, detrital titanomagnetite has been even completely dissolved via diagenesis, giving place to authigenic pyrite and siderite. High TOC content, but low detrital input generated from

Access to Core Facilities and Other Research Resources Provided by the Clinical and Translational Science Awards

PubMed Central

2012-01-01

Abstract  Principal investigators who received Clinical and Translational Science Awards created academic homes for biomedical research. They developed program‐supported websites to offer coordinated access to a range of core facilities and other research resources. Visitors to the 60 websites will find at least 170 generic services, which this review has categorized in the following seven areas: (1) core facilities, (2) biomedical informatics, (3) funding, (4) regulatory knowledge and support, (5) biostatistics, epidemiology, research design, and ethics, (6) participant and clinical interaction resources, and (7) community engagement. In addition, many websites facilitate access to resources with search engines, navigators, studios, project development teams, collaboration tools, communication systems, and teaching tools. Each of these websites may be accessed from a single site, http://www.CTSAcentral.org. The ability to access the research resources from 60 of the nation's academic health centers presents a novel opportunity for investigators engaged in clinical and translational research. Clin Trans Sci 2012; Volume #: 1–5 PMID:22376262

Access to core facilities and other research resources provided by the Clinical and Translational Science Awards.

PubMed

Rosenblum, Daniel

2012-02-01

Principal investigators who received Clinical and Translational Science Awards created academic homes for biomedical research. They developed program-supported websites to offer coordinated access to a range of core facilities and other research resources. Visitors to the 60 websites will find at least 170 generic services, which this review has categorized in the following seven areas: (1) core facilities, (2) biomedical informatics, (3) funding, (4) regulatory knowledge and support, (5) biostatistics, epidemiology, research design, and ethics, (6) participant and clinical interaction resources, and (7) community engagement. In addition, many websites facilitate access to resources with search engines, navigators, studios, project development teams, collaboration tools, communication systems, and teaching tools. Each of these websites may be accessed from a single site, http://www.CTSAcentral.org. The ability to access the research resources from 60 of the nation's academic health centers presents a novel opportunity for investigators engaged in clinical and translational research. © 2012 Wiley Periodicals, Inc.

A note on coarse-grained gravity-flow deposits within proterozoic lacustrine sedimentary rocks, Transvaal sequence, South Africa

NASA Astrophysics Data System (ADS)

Eriksson, P. G.

A widely developed, thin, coarse-matrix conglomerate occurs within early Proterozoic lacustrine mudrocks in the Transvaal Sequence, South Africa. The poorly sorted tabular chert clasts, alternation of a planar clast fabric with disorientated zones, plus normal and inverse grading in the former rock type suggest deposition by density-modified grain-flow and high density turbidity currents. The lower fan-delta slope palæenvironment inferred for the conglomerate is consistent with the lacustrine interpretation for the enclosing mudrock facies. This intracratonic setting contrasts with the marine environment generally associated with density-modified grain-flow deposits.

Search for continuous paleoclimatic record in Holocene lacustrine sediments from Lake District, Chile (40°S)

NASA Astrophysics Data System (ADS)

Bertrand, S.; Fagel, N.

2003-04-01

Our aim is to reconstruct a continuous Holocene climatic evolution related to ENSO variability in southern Chile. We focus on the sedimentary infilling of two glacial lakes from the Lake District Area (38-40°S). The preliminar sedimentological analysis must allow to define the key-site and the best palaeoclimatic proxies. This area, at the foothill of the Cordillera de Los Andes, has been affected by an intense Quaternary volcanic activity and by several historical earthquakes (e.g., Valdivia 1960). After preliminary seismic investigation, four cores were recovered in two lakes selected at the two ends of a N-S transect. (1) Icalma lake (12 km2, 38°S) is located in the Cordillera de Los Andes at an elevation of 1150m and results of the infilling of a glacial umbilic. The two 8m sediment cores consist of an alternation of laminated silts and volcanic layers. The sedimentary record is strongly disturbed by numerous seismic or volcanic events. The cumulated volcanogenic-derived material represents up to 50 % of the core length. In particular, the cores record at -4.50m a pumice layer widespread in the watershed and dated at 2900 yr BP. One core contains pluricentrimetric layers of wood accumulation. They could be due to earthquake impact on the vegetational cover in the watershed. An ubiquitous 6cm-thick slump described at -40 cm may be related with the 1960 Valdivia earthquake. (2) On Puyehue lake (164 km2, 40°S, elevation 185 m), two cores (7 and 11m) have been collected in both underflow and interflow sites. The interflow site (PUII) shows a very well laminated sediment, with only small disturbances due to volcanic and seismic activities. This core will be the key-site for the paleoclimatic study. The second core (PUI) is very rich in organic matter. The sediment is strongly destratified by numerous gas bubbles (methane). These characteristics are due to the dense vegetational cover in the watershed and to the core location near the delta of the main river. This

Fluvial and Lacustrine Processes in Meridiani Planum and the Origin of the Hematite by Aqueous Alteration

NASA Technical Reports Server (NTRS)

Newsom, H. E.; Barber, C. A.; Schelble, R. T.; Hare, T. M.; Feldman, W. C.; Sutherland, V.; Livingston, A.; Lewis, K.

2003-01-01

The prime MER landing site in Meridiani Planum is located on layered materials, including hematite, whose origin as lacustrine or aeolian sediments, or volcanic materials is uncertain. Our detailed mapping of the region provides important constraints on the history of the region. Our mapping of the location of fluvial and lacustrine land forms in the region relative to the layered deposits provides new evidence of a long history of erosion and deposition as has long been noted . In addition, our detailed mapping of the southern boundary of the hematite deposit strongly supports an association between longlived fluvial channels and lacustrine basins and the strongest hematite signatures. This evidence supports an origin of the hematite deposits by interaction with water under ambient conditions in contrast to suggestions of hydrothermal processes due to volcanic or impact crater processes. An important part of the story is the evidence for the localization of the layered deposits due to topographic control induce by the presence of a large early basin we have identified that extends to the north-east of the landing site. Distribution of current channel networks, drainages,

Targeted proteomics coming of age - SRM, PRM and DIA performance evaluated from a core facility perspective.

PubMed

Kockmann, Tobias; Trachsel, Christian; Panse, Christian; Wahlander, Asa; Selevsek, Nathalie; Grossmann, Jonas; Wolski, Witold E; Schlapbach, Ralph

2016-08-01

Quantitative mass spectrometry is a rapidly evolving methodology applied in a large number of omics-type research projects. During the past years, new designs of mass spectrometers have been developed and launched as commercial systems while in parallel new data acquisition schemes and data analysis paradigms have been introduced. Core facilities provide access to such technologies, but also actively support the researchers in finding and applying the best-suited analytical approach. In order to implement a solid fundament for this decision making process, core facilities need to constantly compare and benchmark the various approaches. In this article we compare the quantitative accuracy and precision of current state of the art targeted proteomics approaches single reaction monitoring (SRM), parallel reaction monitoring (PRM) and data independent acquisition (DIA) across multiple liquid chromatography mass spectrometry (LC-MS) platforms, using a readily available commercial standard sample. All workflows are able to reproducibly generate accurate quantitative data. However, SRM and PRM workflows show higher accuracy and precision compared to DIA approaches, especially when analyzing low concentrated analytes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Compositional classification and sedimentological interpretation of the laminated lacustrine sediments at Baumkrichen (Western Austria) using XRF core scanning data

NASA Astrophysics Data System (ADS)

Barrett, Samuel; Tjallingii, Rik; Bloemsma, Menno; Brauer, Achim; Starnberger, Reinhard; Spötl, Christoph; Dulski, Peter

2015-04-01

The outcrop at Baumkirchen (Austria) encloses part of a unique sequence of laminated lacustrine sediments deposited during the last glacial cycle. A ~250m long composite sediment record recovered at this location now continuously covers the periods ~33 to ~45 ka BP (MIS 3) and ~59 to ~73 ka BP (MIS 4), which are separated by a hiatus. The well-laminated (mm-cm scale) and almost entirely clastic sediments reveal alternations of clayey silt and medium silt to very-fine sand layers. Although radiocarbon and optically stimulated luminescence (OSL) dating provide a robust chronology, accurate dating of the sediment laminations appears to be problematic due to very high sedimentation rates (3-8 cm/yr). X-ray fluorescence (XRF) core scanning provided a detailed ~150m long record of compositional changes of the sediments at Baumkirchen. Changes in the sediments are subtle and classification into different facies based on individual elements is therefore subjective. We applied a statistically robust clustering analysis to provide an objective compositional classification without prior knowledge, based on XRF measurements for 15 analysed elements (all those with an acceptable signal-noise ratio: Zr, Sr, Ca, Mn, Cu, Zn, Rb, Ni, Fe, K, Cr, V, Si, Ba, T). The clustering analysis indicates a distinct compositional change between sediments deposited below and above the stratigraphic hiatus, but also differentiates between individual different laminae. Preliminary results suggest variations in the sequence are largely controlled by the relative occurrence of different kinds of sediment represented by different clusters. Three clusters identify well-laminated sediments, visually similar in appearance, each dominated by an anti-correlation between Ca and one or more of the detrital elements K, Zr, Ti, Si and Fe. Two of these clusters occur throughout the entire sequence, one frequently and the other restricted to short sections, while the third occurs almost exclusively below the

Late Cenozoic geology and lacustrine history of Searles Valley, Inyo and San Bernardino Counties, California

USGS Publications Warehouse

Smith, George I.

2009-01-01

Searles Valley is an arid, closed basin lying 70 km east of the south end of the Sierra Nevada, California. It is bounded on the east and northeast by the Slate Range, on the west by the Argus Range and Spangler Hills, and on the south by the Lava Mountains; Searles (dry) Lake occupies the north-central part of the valley. During those parts of late Pliocene and Pleistocene time when precipitation and runoff from the east side of the Sierra Nevada into the Owens River were much greater than at present, a chain of as many as five large lakes was created, of which Searles Lake was third. The stratigraphic record left in Searles Valley when that lake expanded, contracted, or desiccated, is fully revealed by cores from beneath the surface of Searles (dry) Lake and partly recorded by sediments cropping out around the edge of the valley. The subsurface record is described elsewhere. This volume includes six geologic maps (scales: 1:50,000 and 1:10,000) and a text that describes the outcrop record, most of which represents sedimentation since 150 ka. Although this outcrop record is discontinuous, it provides evidence indicating the lake's water depths during each expansion, which the subsurface record does not. Maximum-depth lakes rose to the 2,280-ft (695 m) contour, the level of the spillway that led overflowing waters to Panamint Valley; that spillway is about 660 ft (200 m) above the present dry-lake surface. Several rock units of Tertiary and early Quaternary ages crop out in Searles Valley. Siltstone and sandstone of Tertiary age, mostly lacustrine in nature and locally deformed to near-vertical dips, are exposed in the southern part of the valley, as is the younger(?) upper Miocene Bedrock Spring Formation. Unnamed, mostly mafic volcanic rocks of probable Miocene or Pliocene age are exposed along the north and south edges of the basin. Slightly deformed lacustrine sandstones are mapped in the central-southwestern and southern parts of the study area. The Christmas

[Postspawning survival in lacustrine sock-eyed salmon Oncorhynchus nerka Walb].

PubMed

Markevich, G N; Ivashkin, E G; Pavlov, E D

2011-01-01

The state of gonads, age, structure of scales, and size of specimens of the resident lacustrine form of sock-eyed salmon--kokanee Onchorhynchus nerka--are analyzed. In stocked, previously fishless, lakes, there are specimens that have survived spawning and have remained active for a year or several years. No evidence was found of the possibility of repeated spawning. Thus, such fish do not belong to the spawning stock of the population, and their ecological function is not clear.

Nanoscale semiconductor-insulator-metal core/shell heterostructures: facile synthesis and light emission.

PubMed

Li, Gong Ping; Chen, Rui; Guo, Dong Lai; Wong, Lai Mun; Wang, Shi Jie; Sun, Han Dong; Wu, Tom

2011-08-01

Controllably constructing hierarchical nanostructures with distinct components and designed architectures is an important theme of research in nanoscience, entailing novel but reliable approaches of bottom-up synthesis. Here, we report a facile method to reproducibly create semiconductor-insulator-metal core/shell nanostructures, which involves first coating uniform MgO shells onto metal oxide nanostructures in solution and then decorating them with Au nanoparticles. The semiconductor nanowire core can be almost any material and, herein, ZnO, SnO(2) and In(2)O(3) are used as examples. We also show that linear chains of short ZnO nanorods embedded in MgO nanotubes and porous MgO nanotubes can be obtained by taking advantage of the reduced thermal stability of the ZnO core. Furthermore, after MgO shell-coating and the appropriate annealing treatment, the intensity of the ZnO near-band-edge UV emission becomes much stronger, showing a 25-fold enhancement. The intensity ratio of the UV/visible emission can be increased further by decorating the surface of the ZnO/MgO nanowires with high-density plasmonic Au nanoparticles. These heterostructured semiconductor-insulator-metal nanowires with tailored morphologies and enhanced functionalities have great potential for use as nanoscale building blocks in photonic and electronic applications. This journal is © The Royal Society of Chemistry 2011

Trichloroethylene (TCE) in tree cores to complement a subsurface investigation on residential property near a former electroplating facility.

PubMed

Wilcox, Jeffrey D; Johnson, Kathy M

2016-10-01

Tree cores were collected and analyzed for trichloroethylene (TCE) on a private property between a former electroplating facility in Asheville, North Carolina (USA), and a contaminated wetland/spring complex. TCE was detected in 16 of 31 trees, the locations of which were largely consistent with a "plume core" delineated by a more detailed subsurface investigation nearly 2 years later. Concentrations in tree cores and nearby soil borings were not correlated, perhaps due to heterogeneities in both geologic and tree root structure, spatial and temporal variability in transpiration rates, or interferences caused by other contaminants at the site. Several tree cores without TCE provided evidence for significantly lower TCE concentrations in shallow groundwater along the margins of the contaminated spring complex in an area with limited accessibility. This study demonstrates that tree core analyses can complement a more extensive subsurface investigation, particularly in residential or ecologically sensitive areas.

Partnership between CTSI and Business Schools Can Promote Best Practices for Core Facilities and Resources

PubMed Central

Reeves, Lilith; Dunn‐Jensen, Linda M.; Baldwin, Timothy T.; Tatikonda, Mohan V.

2013-01-01

Abstract Biomedical research enterprises require a large number of core facilities and resources to supply the infrastructure necessary for translational research. Maintaining the financial viability and promoting efficiency in an academic environment can be particularly challenging for medical schools and universities. The Indiana Clinical and Translational Sciences Institute sought to improve core and service programs through a partnership with the Indiana University Kelley School of Business. The program paired teams of Masters of Business Administration students with cores and programs that self‐identified the need for assistance in project management, financial management, marketing, or resource efficiency. The projects were developed by CTSI project managers and business school faculty using service‐learning principles to ensure learning for students who also received course credit for their participation. With three years of experience, the program demonstrates a successful partnership that improves clinical research infrastructure by promoting business best practices and providing a valued learning experience for business students. PMID:23919365

Partnership between CTSI and business schools can promote best practices for core facilities and resources.

PubMed

Reeves, Lilith; Dunn-Jensen, Linda M; Baldwin, Timothy T; Tatikonda, Mohan V; Cornetta, Kenneth

2013-08-01

Biomedical research enterprises require a large number of core facilities and resources to supply the infrastructure necessary for translational research. Maintaining the financial viability and promoting efficiency in an academic environment can be particularly challenging for medical schools and universities. The Indiana Clinical and Translational Sciences Institute sought to improve core and service programs through a partnership with the Indiana University Kelley School of Business. The program paired teams of Masters of Business Administration students with cores and programs that self-identified the need for assistance in project management, financial management, marketing, or resource efficiency. The projects were developed by CTSI project managers and business school faculty using service-learning principles to ensure learning for students who also received course credit for their participation. With three years of experience, the program demonstrates a successful partnership that improves clinical research infrastructure by promoting business best practices and providing a valued learning experience for business students. © 2013 Wiley Periodicals, Inc.

Random field theory to interpret the spatial variability of lacustrine soils

NASA Astrophysics Data System (ADS)

Russo, Savino; Vessia, Giovanna

2015-04-01

The lacustrine soils are quaternary soils, dated from Pleistocene to Holocene periods, generated in low-energy depositional environments and characterized by soil mixture of clays, sands and silts with alternations of finer and coarser grain size layers. They are often met at shallow depth filling several tens of meters of tectonic or erosive basins typically placed in internal Appenine areas. The lacustrine deposits are often locally interbedded by detritic soils resulting from the failure of surrounding reliefs. Their heterogeneous lithology is associated with high spatial variability of physical and mechanical properties both along horizontal and vertical directions. The deterministic approach is still commonly adopted to accomplish the mechanical characterization of these heterogeneous soils where undisturbed sampling is practically not feasible (if the incoherent fraction is prevalent) or not spatially representative (if the cohesive fraction prevails). The deterministic approach consists on performing in situ tests, like Standard Penetration Tests (SPT) or Cone Penetration Tests (CPT) and deriving design parameters through "expert judgment" interpretation of the measure profiles. These readings of tip and lateral resistances (Rp and RL respectively) are almost continuous but highly variable in soil classification according to Schmertmann (1978). Thus, neglecting the spatial variability cannot be the best strategy to estimated spatial representative values of physical and mechanical parameters of lacustrine soils to be used for engineering applications. Hereafter, a method to draw the spatial variability structure of the aforementioned measure profiles is presented. It is based on the theory of the Random Fields (Vanmarcke 1984) applied to vertical readings of Rp measures from mechanical CPTs. The proposed method relies on the application of the regression analysis, by which the spatial mean trend and fluctuations about this trend are derived. Moreover, the

Facile synthesis of hierarchical Co3O4@MnO2 core-shell arrays on Ni foam for asymmetric supercapacitors

NASA Astrophysics Data System (ADS)

Huang, Ming; Zhang, Yuxin; Li, Fei; Zhang, Lili; Wen, Zhiyu; Liu, Qing

2014-04-01

Hierarchical Co3O4@MnO2 core-shell arrays on Ni foam have been fabricated by a facile hydrothermal approach and further investigated as the electrode for high-performance supercapacitors. Owing to the high conductivity of the well-defined mesoporous Co3O4 nanowire arrays in combination with the large surface area provided by the ultrathin MnO2 nanosheets, the unique designed Co3O4@MnO2 core-shell arrays on Ni foam have exhibited a high specific capacitance (560 F g-1 at a current density of 0.2 A g-1), good rate capability, and excellent cycling stability (95% capacitance retention after 5000 cycles). An asymmetric supercapacitor with Co3O4@MnO2 core-shell nanostructure as the positive electrode and activated microwave exfoliated graphite oxide activated graphene (MEGO) as the negative electrode yielded an energy density of 17.7 Wh kg-1 and a maximum power density of 158 kW kg-1. The rational design of the unique core-shell array architectures demonstrated in this work provides a new and facile approach to fabricate high-performance electrode for supercapacitors.

An isotopic study of a fluvial-lacustrine sequence: The Plio-Pleistocene koobi fora sequence, East Africa

USGS Publications Warehouse

Cerling, T.E.; Bowman, J.R.; O'Neil, J.R.

1988-01-01

Stable isotopic analyses of Plio-Pleistocene and modern sediments in the fluvial-lacustrine system occupying the Turkana Basin, East Africa provide constraints on the paleoenvironmental and diagenetic histories of the Pliocene through the Recent sediments in the basin. The ??13C values for carbonates in lacustrine sediments range from -15 to +22??? relative to PDB, depending on the varying proportions of CO2 from the atmospheric reservoir and from various metabolic sources. The ??18O values of carbonates in lacustrine sediments indicate that the isotopic composition of paleolake water varied by over 10??? from the Pliocene to the present. The ??13C values for pedogenic carbonates record paleoccologic variations and suggest that C4 plants did not become well established in the preserved depositional parts of the basin until about 1.8 myr ago. The ??18O values pedogenic carbonates suggest a range of over 10??? for the isotopic composition of soil water during this interval. They also suggest a period of major climatic instability from about 3.4 to 3.1 myr and at about 1.8 myr. Together, the ??13C and ??18O values of pedogenic carbonates indicate that the present conditions are as arid and hot as any that had prevailed during deposition of these Plio-Pleistocene sediments. ?? 1988.

Seismic Triggers of Lacustrine Subaqueous Landslides in Lake Champlain, USA

NASA Astrophysics Data System (ADS)

Manley, P.; Manley, T.; Ghosh, S. J.; Rosales-Underbrink, P.; Silverhart, P.

2017-12-01

Lacustrine slumps and debris flows (landslides) have been identified in Lake Champlain via Multibeam and CHIRP (compressed high intensity radar pulse) seismic profile data. Numerous large landslides studied by Ghosh (2012), Rosales-Underbrink (2015), and Silverhart (2016) have shown that many of these landslides are coeval. All landslides failed on a specific interface between marine Champlain Sea and modern lacustrine Lake Champlain sediments. Utilizing radionuclide dating on sediment from the unfailed slopes or undisturbed sediment above failed deposits, sedimentation rates were determined and used to calculate the approximate failure ages for each of the landslides studied. The northernmost failure, south of the Bouquet River, occurred about 950-1200 cal yr BP and is the first mass wasting event of this age to be recorded on Lake Champlain. The remaining landslides failed about 4500-5200 cal yr BP and agree with nearby Western Quebec Seismic Zone (WQSZ) with clusters of terrestrial landslides occurring at 1000 and 5000 cal yr BP triggered by large earthquakes (Brooks, 2015) along the same interface. The 5000 cal yr BP event has been attributed to a M 6.4 or greater earthquake within the WQSZ. The coeval landslides observed in Lake Champlain were likely triggered by this same earthquake. Lake tsunami models show that these simultaneous landslide failures can generate surface waves wave that can impact the Lake Champlain shoreline within 3-10 minutes after the earthquake.

STEADY STATE MODELING OF THE MINIMUM CRITICAL CORE OF THE TRANSIENT REACTOR TEST FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anthony L. Alberti; Todd S. Palmer; Javier Ortensi

2016-05-01

With the advent of next generation reactor systems and new fuel designs, the U.S. Department of Energy (DOE) has identified the need for the resumption of transient testing of nuclear fuels. The DOE has decided that the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory (INL) is best suited for future testing. TREAT is a thermal neutron spectrum, air-cooled, nuclear test facility that is designed to test nuclear fuels in transient scenarios. These specific scenarios range from simple temperature transients to full fuel melt accidents. DOE has expressed a desire to develop a simulation capability that will accurately modelmore » the experiments before they are irradiated at the facility. It is the aim for this capability to have an emphasis on effective and safe operation while minimizing experimental time and cost. The multi physics platform MOOSE has been selected as the framework for this project. The goals for this work are to identify the fundamental neutronics properties of TREAT and to develop an accurate steady state model for future multiphysics transient simulations. In order to minimize computational cost, the effect of spatial homogenization and angular discretization are investigated. It was found that significant anisotropy is present in TREAT assemblies and to capture this effect, explicit modeling of cooling channels and inter-element gaps is necessary. For this modeling scheme, single element calculations at 293 K gave power distributions with a root mean square difference of 0.076% from those of reference SERPENT calculations. The minimum critical core configuration with identical gap and channel treatment at 293 K resulted in a root mean square, total core, radial power distribution 2.423% different than those of reference SERPENT solutions.« less

Sedimentary architecture of a sub-lacustrine debris fan: Eocene Dongying Depression, Bohai Bay Basin, east China

NASA Astrophysics Data System (ADS)

Liu, Jianping; Xian, Benzhong; Wang, Junhui; Ji, Youliang; Lu, Zhiyong; Liu, Saijun

2017-12-01

The sedimentary architectures of submarine/sublacustrine fans are controlled by sedimentary processes, geomorphology and sediment composition in sediment gravity flows. To advance understanding of sedimentary architecture of debris fans formed predominantly by debris flows in deep-water environments, a sub-lacustrine fan (Y11 fan) within a lacustrine succession has been identified and studied through the integration of core data, well logging data and 3D seismic data in the Eocene Dongying Depression, Bohai Bay Basin, east China. Six types of resedimented lithofacies can be recognized, which are further grouped into five broad lithofacies associations. Quantification of gravity flow processes on the Y11 fan is suggested by quantitative lithofacies analysis, which demonstrates that the fan is dominated by debris flows, while turbidity currents and sandy slumps are less important. The distribution, geometry and sedimentary architecture are documented using well data and 3D seismic data. A well-developed depositional lobe with a high aspect ratio is identified based on a sandstone isopach map. Canyons and/or channels are absent, which is probably due to the unsteady sediment supply from delta-front collapse. Distributary tongue-shaped debris flow deposits can be observed at different stages of fan growth, suggesting a lobe constructed by debrite tongue complexes. Within each stage of the tongue complexes, architectural elements are interpreted by wireline log motifs showing amalgamated debrite tongues, which constitute the primary fan elements. Based on lateral lithofacies distribution and vertical sequence analysis, it is proposed that lakefloor erosion, entrainment and dilution in the flow direction lead to an organized distribution of sandy debrites, muddy debrites and turbidites on individual debrite tongues. Plastic rheology of debris flows combined with fault-related topography are considered the major factors that control sediment distribution and fan

Conditions for Land Subsidence and Ground Failure in Lacustrine Sediments, the Case of West Chapala Basin.

NASA Astrophysics Data System (ADS)

Hernandez-Marin, M.; Pacheco, J.; Ortiz-Lozano, J. A.; Ramirez-Cortes, A.; Araiza, G.

2014-12-01

Surface deformation in the form of land subsidence and ground failure in the Chapala Basin has caused serious damage to structures, mostly homes. In this work, the conditions for the occurrence of deformation particularly regarding the physical and mechanical properties of the soil are discussed. In 2012 a maximum land subsidence of 7.16 cm in a short period of 8 months was recorded with maximum velocities of deformation close to 0.89 centimeters per month. Natural conditions of the zone of study include a lacustrine low land with the perennial Chapala Lake, surrounded by ranges formed by volcanic extrusive rocks, mostly basalts and andesites. Two soil cores of 11 meters depth show the predominance of fine soil but with the incrustation of several sandy lenses of volcanic ash. In the first core closer to the piedmont, the volcanic ash presents an accumulated thickness close to three meters, starting at 4.5 meters depth; on the contrary, this thickness in the second core closer to the lake is critically reduced to no more than 50 centimeters. Even though the predominance of fine soil is significant, water-content averages 100 % and the liquid limit is low, suggesting amongst other possibilities, low content of clay or at least low content of smectites or allophanes in the clayey portion. Other properties of the soil are being determined for analyses. The occurrence of three alignments of ground failures in the community of Jocotepec at the west, mostly faults, suggests highly heterogeneous subsoil. The high volumes of groundwater withdrawn from the local aquifers mainly for agriculture are directly contributing to the increase of the effective stress and surface deformation, however, the relationship between level descents and surficial deformation is still not clear.

Mercury free microscopy: an opportunity for core facility directors.

PubMed

Baird, T Regan; Kaufman, Daniel; Brown, Claire M

2014-07-01

Mercury Free Microscopy (MFM) is a new movement that encourages microscope owners to choose modern mercury free light sources to replace more traditional mercury based arc lamps. Microscope performance is enhanced with new solid state technologies because they offer a more stable light intensity output and have a more uniform light output across the visible spectrum. Solid state sources not only eliminate mercury but also eliminate the cost of consumable bulbs (lifetime ∼200 hours), use less energy, reduce the instrument down time when bulbs fail and reduce the staff time required to replace and align bulbs. With lifetimes on the order of tens of thousands of hours, solid state replacements can pay for themselves over their lifetime with the omission of consumable, staff (no need to replace and align bulbs) and energy costs. Solid state sources are also sustainable and comply with institutional and government body mandates to reduce energy consumption, carbon footprints and hazardous waste. MFM can be used as a mechanism to access institutional financial resources for sustainable technology through a variety of stakeholders to defray the cost to microscope owners for the initial purchase of solid state sources or the replacement cost of mercury based sources. Core facility managers can take a lead in this area as "green" ambassadors for their institution by championing a local MFM program that will save their institution money and energy and eliminate mercury from the waste stream. Managers can leverage MFM to increase the visibility of their facility, their impact within the institution, and as a vital educational resource for scientific and administrative consultation.

Prokaryotic Community in Lacustrine Sediments of Byers Peninsula (Livingston Island, Maritime Antarctica).

PubMed

Gugliandolo, Concetta; Michaud, Luigi; Lo Giudice, Angelina; Lentini, Valeria; Rochera, Carlos; Camacho, Antonio; Maugeri, Teresa Luciana

2016-02-01

Byers Peninsula (Livingston Island, Antarctica), the largest seasonally ice-free region of the Maritime Antarctica, holds a large number of lakes, ponds, and streams. The prokaryotic structure and bacterial diversity in sediment samples collected during the 2008-2009 austral summer from five inland lakes, two coastal lakes, and an estuarine site were analyzed by Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) and 16S rRNA 454 tag pyrosequencing techniques, respectively. Differently from inland lakes, which range around the oligotrophic status, coastal lakes are eutrophic environments, enriched by nutrient inputs from marine animals. Although the prokaryotic abundances (estimated as DAPI stained cells) in sediment samples were quite similar among inland and coastal lakes, Bacteria always far dominated over Archaea. Despite the phylogenetic analysis indicated that most of sequences were affiliated to a few taxonomic groups, mainly referred to Proteobacteria, Bacteroidetes, and Actinobacteria, their relative abundances greatly differed from each site. Differences in bacterial composition showed that lacustrine sediments were more phyla rich than the estuarine sediment. Proteobacterial classes in lacustrine samples were dominated by Betaproteobacteria (followed by Alphaproteobacteria, Deltaproteobacteria, and Gammaproteobacteria), while in the estuarine sample, they were mainly related to Gammaproteobacteria (followed by Deltaproteobacteria, Epsilonproteobacteria, Alphaproteobacteria, and Betaproteobacteria). Higher number of sequences of Alphaproteobacteria, Cyanobacteria, Verrucomicrobia, and Planctomycetes were observed in sediments of inland lakes compared to those of coastal lakes, whereas Chloroflexi were relatively more abundant in the sediments of coastal eutrophic lakes. As demonstrated by the great number of dominant bacterial genera, bacterial diversity was higher in the sediments of inland lakes than that in coastal lakes

Mesozoic lacustrine system in the Parnaíba Basin, northeastern Brazil: Paleogeographic implications for west Gondwana

NASA Astrophysics Data System (ADS)

Cardoso, Alexandre Ribeiro; Nogueira, Afonso César Rodrigues; Abrantes, Francisco Romério; Rabelo, Cleber Eduardo Neri

2017-03-01

The fragmentation of the West Gondwana during Early Triassic to Cretaceous was marked by intense climatic changes, concomitant with the establishment of extensive desertic/lacustrine systems. These deposits succeeded the emplacement and extrusion of lava flows, related to the pre-rift phase and initial opening of the Equatorial Atlantic Ocean. The thermal phase is recorded in the Upper Jurassic-Lower Cretaceous Pastos Bons Formation, exposed mainly in southeast parts of the Parnaíba Basin, Northeastern Brazil. The sedimentary facies of this unit were grouped in two facies associations (FA), representative of a shallow lacustrine system, influenced by episodic hyperpycnal and oscillatory flows. Central lake facies association (FA1) is composed by laminated mudstone (Ml), sandstone/mudstone rhythmite (S/Mr) and sandstone with even-parallel lamination (Sel). Flysch-like delta front (FA2) consists in sandstones with wave structures (Sw), sandstones with even-parallel stratification (Ses), massive sandstones (Sm), sandstones with soft-sediment deformation structures (Sd) and laminated mudstones (Ml). FA1 was deposited in the deepest portions of the lake, characterized by low energy, episodically disturbed by siliciclastic influx. FA2 presents sandy deposits generated by unconfined flow, probably fed by ephemeral stream flows that generated thickening upward of tabular sandstone beds. The progressive filling of the lake resulted in recurrent shoaling up of the water level and reworking by wave action. The installation of Pastos Bons lakes was controlled by thermal subsidence, mainly in restricted depocenters. The siliciclastic fluvial inflow can be related to the adjacent humid desertic facies, formed under climatic attenuation, typical of post-Triassic period, with reduced biological activity. Smectite and abundant feldspars, in lacustrine facies, corroborate an arid climate, with incipient chemical weathering. The new facies and stratigraphic data present in this

Mechanosensory based orienting behaviors in fluvial and lacustrine populations of mottled sculpin (Cottus bairdi)

Treesearch

Sheryl Coombs; Gary D. Grossman

2006-01-01

We compared prey-orienting and rheotactic behaviors in a fluvial (Coweeta Creek) and lacustrine (Lake Michigan) population of mottled sculpin. Blinded sculpin from both populations exhibited unconditioned, mechanosensory based rheotaxis to low velocity flows. Whereas Lake Michigan sculpin generally showed increasing levels of positive rheotaxis to increasing velocities...

Distinguishing megathrust from intraplate earthquakes using lacustrine turbidites (Laguna Lo Encañado, Central Chile)

NASA Astrophysics Data System (ADS)

Van Daele, Maarten; Araya-Cornejo, Cristian; Pille, Thomas; Meyer, Inka; Kempf, Philipp; Moernaut, Jasper; Cisternas, Marco

2017-04-01

One of the main challenges in seismically active regions is differentiating paleo-earthquakes resulting from different fault systems, such as the megathrust versus intraplate faults in subductions settings. Such differentiation is, however, key for hazard assessments based on paleoseismic records. Laguna Lo Encañado (33.7°S; 70.3°W; 2492 m a.s.l.) is located in the Central Chilean Andes, 50 km east of Santiago de Chile, a metropole with about 7,000,000 inhabitants. During the last century the study area experienced 3 large megathrust earthquakes (1906, 1985 and 2010) and 2 intraplate earthquakes (1945 and 1958) (Lomnitz, 1960). While the megathrust earthquakes cause Modified Mercalli Intensities (MMIs) of VI to VII at the lake (Van Daele et al., 2015), the intraplate earthquakes cause peak MMIs up to IX (Sepúlveda et al., 2008). Here we present a turbidite record of Laguna Lo Encañado going back to 1900 AD. While geophysical data (3.5 kHz subbottom seismic profiles and side-scan sonar data) provides a bathymetry and an overview of the sedimentary environment, we study 15 short cores in order to understand the depositional processes resulting in the encountered lacustrine turbidites. All mentioned earthquakes triggered turbidites in the lake, which are all linked to slumps in proximal areas, and are thus resulting from mass wasting of the subaquatic slopes. However, turbidites linked to the intraplate earthquakes are additionally covered by turbidites of a finer-grained, more clastic nature. We link the latter to post-seismic erosion of onshore landslides, which need higher MMIs to be triggered than subaquatic mass movements (Howarth et al., 2014). While intraplate earthquakes can cause MMIs up to IX and higher, megathrust earthquakes do not cause sufficiently high MMIs at the lake to trigger voluminous onshore landslides. Hence, the presence of these post-seismic turbidites allows to distinguish turbidites triggered by intraplate earthquakes from those

In-core flux sensor evaluations at the ATR critical facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Troy Unruh; Benjamin Chase; Joy Rempe

2014-09-01

Flux detector evaluations were completed as part of a joint Idaho State University (ISU) / Idaho National Laboratory (INL) / French Atomic Energy commission (CEA) ATR National Scientific User Facility (ATR NSUF) project to compare the accuracy, response time, and long duration performance of several flux detectors. Special fixturing developed by INL allows real-time flux detectors to be inserted into various ATRC core positions and perform lobe power measurements, axial flux profile measurements, and detector cross-calibrations. Detectors initially evaluated in this program include the French Atomic Energy Commission (CEA)-developed miniature fission chambers; specialized self-powered neutron detectors (SPNDs) developed by themore » Argentinean National Energy Commission (CNEA); specially developed commercial SPNDs from Argonne National Laboratory. As shown in this article, data obtained from this program provides important insights related to flux detector accuracy and resolution for subsequent ATR and CEA experiments and flux data required for bench-marking models in the ATR V&V Upgrade Initiative.« less

Stratigraphy, correlation, depositional setting, and geophysical characteristics of the Oligocene Snowshoe Mountain Tuff and Creede Formation in two cored boreholes

USGS Publications Warehouse

Larsen, Daniel; Nelson, Philip H.

2000-01-01

Core descriptions and geophysical logs from two boreholes (CCM-1 and CCM-2) in the Oligocene Snowshoe Mountain Tuff and Creede Formation, south-central Colorado, are used to interpret sedimentary and volcanic facies associations and their physical properties. The seven facies association include a mixed sequence of intracaldera ash-flow tuffs and breccias, alluvial and lake margin deposits, and tuffaceous lake beds. These deposits represent volcanic units related to caldera collapse and emplacement of the Snowshoe Mountain Tuff, and sediments and pyroclastic material deposited in the newly formed caldera basin, Early sedimentation is interpreted to have been rapid, and to have occurred in volcaniclastic fan environments at CCM-1 and in a variery of volcaniclastic fan, braided stream shallow lacustrine, and mudflat environments at CCM-2. After an initial period of lake-level rise, suspension settling, turbidite, and debris-flow sedimentation occurred in lacustrine slope and basin environments below wave base. Carbonate sedimentation was initially sporadic, but more continuous in the latter part of the recorded lake history (after the H fallout tuff). Sublacustrine-fan deposition occurred at CCM-1 after a pronounced lake-level fall and subsequent rise that preceded the H tuff. Variations in density, neutron, gamma-ray, sonic, and electrical properties of deposits penetrated oin the two holes reflect variations in lithology, porosity, and alteration. Trends in the geophysical properties of the lacustrine strata are linked to downhole changes in authigenic mineralology and a decrease in porosity interpreted to have resulted primarily from diagenesis. Lithological and geophysical characteristics provide a basis for correlation of the cores; however, mineralogical methods of correlation are hampered by the degree of diagenesis and alteration.

Geomorphic Drainage Capture Recorded by Oxygen Isotopes of Green River Formation Lacustrine Mudstone, Eocene, Wyoming

NASA Astrophysics Data System (ADS)

Doebbert, A. C.; Booth, A. L.; Carroll, A.; Chamberlain, C.; Rhodes, M.

2005-12-01

The isotopic composition of cement and other meteoric precipitates are increasingly being used to interpret orogenic uplift histories, based on the relationship between altitude and rainwater δ18O. However, other variables such as changing regional drainage patterns may also affect the downstream composition of surface waters, especially when multiple drainages commingle in a lake. The Green River Formation contains some of the best documented lacustrine deposits in the world, making it ideal for examining such issues. Carbonate mudstone in balanced-fill facies of the lower LaClede Bed averages 3.41‰ (PDB), and records a deep, saline to brackish lake that fluctuated near its sill. In contrast, overfilled facies of the upper LaClede Bed record a freshwater lake, and δ18O reaches values as low as -9.72‰. This transition occurred shortly after deposition of the Analcite Tuff at 48.94 ± 0.12 Ma (Smith et al., 2003), and was geologically abrupt. Based on 40Ar/39Ar-calibrated sediment accumulation rates it required no more than 200-300 ky. An almost identical transition occurs in two cores separated by about 30 km, making local diagenesis an unlikely cause. The magnitude of δ18O change is similar to that in some uplift studies, but its rapidity virtually excludes uplift as a controlling mechanism. Instead, we propose that both the change in sedimentation and the sharp decrease in δ18O are the result of a drainage capture event. The addition of a new drainage to the basin may have adjusted isotopic values in two ways: by introducing runoff with relatively low δ18O, and by decreasing residence time (and therefore evaporation) of lake water. Decreasing 87Sr/86Sr across the same transition suggests that the newly added waters may have been sourced from rising volcanic topography to the north in the Absaroka province. Although this rising topography allows for the possibility of some uplift component, the rate of change in lacustrine δ18O is consistent with

DISTRIBUTION COEFICIENTS (KD) GENERATED FROM A CORE SAMPLE COLLECTED FROM THE SALTSTONE DISPOSAL FACILITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Almond, P.; Kaplan, D.

Core samples originating from Vault 4, Cell E of the Saltstone Disposal Facility (SDF) were collected in September of 2008 (Hansen and Crawford 2009, Smith 2008) and sent to SRNL to measure chemical and physical properties of the material including visual uniformity, mineralogy, microstructure, density, porosity, distribution coefficients (K{sub d}), and chemical composition. Some data from these experiments have been reported (Cozzi and Duncan 2010). In this study, leaching experiments were conducted with a single core sample under conditions that are representative of saltstone performance. In separate experiments, reducing and oxidizing environments were targeted to obtain solubility and Kd valuesmore » from the measurable species identified in the solid and aqueous leachate. This study was designed to provide insight into how readily species immobilized in saltstone will leach from the saltstone under oxidizing conditions simulating the edge of a saltstone monolith and under reducing conditions, targeting conditions within the saltstone monolith. Core samples were taken from saltstone poured in December of 2007 giving a cure time of nine months in the cell and a total of thirty months before leaching experiments began in June 2010. The saltstone from Vault 4, Cell E is comprised of blast furnace slag, class F fly ash, portland cement, and Deliquification, Dissolution, and Adjustment (DDA) Batch 2 salt solution. The salt solution was previously analyzed from a sample of Tank 50 salt solution and characterized in the 4QCY07 Waste Acceptance Criteria (WAC) report (Zeigler and Bibler 2009). Subsequent to Tank 50 analysis, additional solution was added to the tank solution from the Effluent Treatment Project as well as from inleakage from Tank 50 pump bearings (Cozzi and Duncan 2010). Core samples were taken from three locations and at three depths at each location using a two-inch diameter concrete coring bit (1-1, 1-2, 1-3; 2-1, 2-2, 2-3; 3-1, 3-2, 3-3) (Hansen

Lacustrine-fluvial interactions in Australia's Riverine Plains

NASA Astrophysics Data System (ADS)

Kemp, Justine; Pietsch, Timothy; Gontz, Allen; Olley, Jon

2017-06-01

Climatic forcing of fluvial systems has been a pre-occupation of geomorphological studies in Australia since the 1940s. In the Riverine Plain, southeastern Australia, the stable tectonic setting and absence of glaciation have combined to produce sediment loads that are amongst the lowest in the world. Surficial sediments and landforms exceed 140,000 yr in age, and geomorphological change recorded in the fluvial, fluvio-lacustrine and aeolian features have provided a well-studied record of Quaternary environmental change over the last glacial cycle. The region includes the Willandra Lakes, whose distinctive lunette lakes preserve a history of water-level variations and ecological change that is the cornerstone of Australian Quaternary chronostratigraphy. The lunette sediments also contain an ancient record of human occupation that includes the earliest human fossils yet found on the Australian continent. To date, the lake-level and palaeochannel records in the Lachlan-Willandra system have not been fully integrated, making it difficult to establish the regional significance of hydrological change. Here, we compare the Willandra Lakes environmental record with the morphology and location of fluvial systems in the lower Lachlan. An ancient channel belt of the Lachlan, Willandra Creek, acted as the main feeder channel to Willandra Lakes before channel avulsion caused the lakes to dry out in the late Pleistocene. Electromagnetic surveys, geomorphological and sedimentary evidence are used to reconstruct the evolution of the first new channel belt following the avulsion. Single grain optical dating of floodplain sediments indicates that sedimentation in the new Middle Billabong Palaeochannel had commenced before 18.4 ± 1.1 ka. A second avulsion shifted its upper reaches to the location of the present Lachlan River by 16.2 ± 0.9 ka. The timing of these events is consistent with palaeohydrological records reconstructed from Willandra Lakes and with the record of

Diagenetic variation at the lamina scale in lacustrine organic-rich shales: Implications for hydrocarbon migration and accumulation

NASA Astrophysics Data System (ADS)

Liang, Chao; Cao, Yingchang; Liu, Keyu; Jiang, Zaixing; Wu, Jing; Hao, Fang

2018-05-01

Lacustrine carbonate-rich shales are well developed within the Mesozoic-Cenozoic strata of the Bohai Bay Basin (BBB) of eastern China and across southeast Asia. Developing an understanding of the diagenesis of these shales is essential to research on mass balance, diagenetic fluid transport and exchange, and organic-inorganic interactions in black shales. This study investigates the origin and distribution of authigenic minerals and their diagenetic characteristics, processes, and pathways at the scale of lacustrine laminae within the Es4s-Es3x shale sequence of the BBB. The research presented in this study is based on thin sections, field emission scanning electron microscope (FESEM) and SEM-catholuminescence (CL) observations of well core samples combined with the use of X-ray diffraction (XRD), energy dispersive spectroscopy, electron microprobe analysis, and carbon and oxygen isotope analyses performed using a laser microprobe mass spectrometer. The dominant lithofacies within the Es4s-Es3x sequence are a laminated calcareous shale (LCS-1) and a laminated clay shale (LCS-2). The results of this study show that calcite recrystallization1 is the overarching diagenetic process affecting the LCS-1, related to acid generation from organic matter (OM) thermal evolution. This evolutionary transition is the key factor driving the diagenesis of this lithofacies, while the transformation of clay minerals is the main diagenetic attribute of the LCS-2. Diagenetic differences occur within different laminae and at variable locations within the same lamina level, controlled by variations in mineral composition and the properties of laminae interfaces. The diagenetic fluid migration scale is vertical and responses (dissolution and replacement) are limited to individual laminae, between zero and 100 μm in width. In contrast, the dominant migration pathway for diagenetic fluid is lateral, along the abrupt interfaces between laminae boundaries, which leads to the vertical

17 CFR 37.6 - Compliance with core principles.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 17 Commodity and Securities Exchanges 1 2011-04-01 2011-04-01 false Compliance with core... DERIVATIVES TRANSACTION EXECUTION FACILITIES § 37.6 Compliance with core principles. (a) In general. To... transaction execution facility must have the capacity to be, and be, in compliance with the core principles of...

17 CFR 37.6 - Compliance with core principles.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Compliance with core... DERIVATIVES TRANSACTION EXECUTION FACILITIES § 37.6 Compliance with core principles. (a) In general. To... transaction execution facility must have the capacity to be, and be, in compliance with the core principles of...

From submarine to lacustrine groundwater discharge

USGS Publications Warehouse

Lewandowski, Jörg; Meinikmann, Karin; Pöschke, Franziska; Nützmann, Gunnar; Rosenberry, Donald O.

2017-01-01

Submarine groundwater discharge (SGD) and its role in marine nutrient cycling are well known since the last decade. The freshwater equivalent, lacustrine groundwater discharge (LGD), is often still disregarded, although first reports of LGD are more than 50 years old. We identify nine different reasons why groundwater has long been disregarded in both freshwater and marine environments such as invisibility of groundwater discharge, the size of the interface and its difficult accessibility. Although there are some fundamental differences in the hydrology of SGD and LGD, caused primarily by seawater recirculation that occurs only in cases of SGD, there are also a lot of similarities such as a focusing of discharge to near-shore areas. Nutrient concentrations in groundwater near the groundwater–surface water interface might be anthropogenically enriched. Due to spatial heterogeneity of aquifer characteristics and biogeochemical processes, the quantification of groundwater-borne nutrient loads is challenging. Both nitrogen and phosphorus might be mobile in near-shore aquifers and in a lot of case studies large groundwater-borne nutrient loads have been reported.

Hydrocarbon potential of Early Cretaceous lacustrine sediments from Bima Formation, Yola Sub-basin, Northern Benue Trough, NE Nigeria: Insight from organic geochemistry and petrology

NASA Astrophysics Data System (ADS)

Sarki Yandoka, Babangida M.; Abdullah, Wan Hasiah; Abubakar, M. B.; Adegoke, Adebanji Kayode; Maigari, A. S.; Haruna, A. I.; Yaro, Usman Y.

2017-05-01

The Early Cretaceous lacustrine sediments from Bima Formation in the Yola Sub-basin, Northern Benue Trough, northeastern Nigeria were studied based on organic geochemistry and petrology. This is in other to provide information on hydrocarbon generation potential; organic matter type (quality), richness (quantity), origin/source inputs, redox conditions (preservation) and thermal maturation in relation to thermal effect of Tertiary volcanics. The total organic carbon (TOC) contents ranges from 0.38 to 0.86 wt % with extractable organic matter (EOM) below 1000 ppm and pyrolysis S2 yield values from 0.16 to 0.68 mg/g, suggesting poor to fair source rock richness. Based on kerogen pyrolysis and microscopy coupled with biomarker parameters, the organic matters contain Type I (lacustrine algae), Type III (terrestrially derived land-plants) and Type IV kerogens deposited in a mixed lacustrine-terrestrial environment under suboxic to relatively anoxic conditions. This suggest potential occurrence of Early Cretaceous lacustrine sediments (perhaps Lower Cretaceous petroleum system) in Yola Sub-basin of the Northern Benue Trough as present in the neighbouring basins of Chad, Niger and Sudan Republics that have both oil and gas generation potential within the same rift trend (WCARS). Vitrinite reflectance (%Ro) and Tmax values of the lacustrine shales ranges from 1.12 to 2.32 VRo% and 448-501 °C, respectively, indicating peak-late to post-maturity stage. This is supported by the presence of dark brown palynomorphs, amorphous organic matter and phytoclasts as well as inertinite macerals. Consequently, the organic matters in the lacustrine shales of Bima Formation in the Yola Sub-basin appeared as a source of oil (most likely even waxy) and gas prone at a relatively deeper part of the basin. However, the high thermal maturity enhanced the organic matters and most of the hydrocarbons that formed in the course of thermal maturation were likely expelled to the reservoir rock units

Evidences of melting of terrestrial sediments and paleoenvironment changes during the Younger Dryas in tectonic lacustrine basins of Transmexican Volcanic Belt, Mexico.

NASA Astrophysics Data System (ADS)

Israde-Alcantara, I.

2017-12-01

It is well known in the sedimentary record of several parts of the world that during the Younger Dryas interval (YD) ocurred an abrupt environmental change between 12,900 and 11,700 cal yr BP (10,900 to 10,000 14C BP). In the lacustrine basins this changes are often preserved and in some Mexican lakes this is a distinctive stratigraphic marker for the YD. We analized the proxies of this event in cores of two lakes (Chapala, Cuitzeo) and three trenches of ex-lakes (Acambay,Texcoco and El Cedral). Deposits consist of fine detrital material with often Pleistocene fossil vertebrate assemblages. At the Chapala, Cuitzeo, Acambay, and Tocuila lacustrine environments are found in association with a distinctive dark organic layer showing sharp changes in the diatom, pollen, mineralogical and geochemical record. Includes also microscopic magnetic, Fe-rich spherules, silica melted droplets with aerodynamic shapes (tektites), followed by large amounts of charcoal, and sometimes nanodiamonds (Cuitzeo), that were deposited at the onset of the YD or in the limit Pleistocene-Holocene. These unusual materials are buried more than 2.50 meters and were not observed above or below the Younger Dryas sediments at these sites. The geochemistry of the microspherules indicates that they are not volcanic, anthropogenic or authigenic origin. A very distinctive feature is the shape of the spherules, ovoid, polygonal, filigreed or dendritic indicating melting and quenching infering that are product of an impact event. Their morphologies includes hollow shells caused by de-gassing of elements at very high temperatures causing a flattened side with a "skirt" structure by a high-velocity collision.Our results are consistent with the Firestone hypothesis.

The influence of authigenic clay formation on the mineralogy and stable isotopic record of lacustrine carbonates

NASA Astrophysics Data System (ADS)

Bristow, Thomas F.; Kennedy, Martin J.; Morrison, Keith D.; Mrofka, David D.

2012-08-01

The mineralogical, compositional and stable isotopic variability of lacustrine carbonates are frequently used as proxies for ancient paleoenvironmental change in continental settings, under the assumption that precipitated carbonates reflect conditions and chemistry of ancient lake waters. In some saline and alkaline lake systems, however, authigenic clay minerals, forming at or near the sediment water interface, are a major sedimentary component. Often these clays are rich in Mg, influencing the geochemical budget of lake waters, and are therefore expected to influence the properties of contemporaneous authigenic carbonate precipitates (which may also contain Mg). This paper documents evidence for a systematic feedback between clay mineral and carbonate authigenesis through multiple precessionally driven, m-scale sedimentary cycles in lacustrine oil-shale deposits of the Eocene Green River Formation from the Uinta Basin (NE Utah). In the studied section, authigenic, Mg-rich, trioctahedral smectite content varies cyclically between 9 and 39 wt.%. The highest concentrations occur in oil-shales and calcareous mudstones deposited during high lake level intervals that favored sedimentary condensation, lengthening the time available for clay diagenesis and reducing dilution by other siliciclastic phases. An inverse relation between dolomite percentage of carbonate and trioctahedral smectite abundance suggests the Mg uptake during clay authigenesis provides a first order control on carbonate mineralogy that better explains carbonate mineralogical trends than the possible alternative controls of (1) variable Mg/Ca ratios in lake water and (2) degree of microbial activity in sediments. We also observe that cyclical change in carbonate mineralogy, believed to be induced by clay authigenesis, also causes isotopic covariation between δ13CPDB and δ18OPDB of bulk sediments because of differences in the equilibrium fractionation factors of dolomite and calcite (˜2‰ and ˜2

Dating lacustrine episodes in the eastern Sahara by the epimerization of isoleucine in ostrich eggshells

USGS Publications Warehouse

Miller, G.H.; Wendorf, F.; Ernst, R.; Schild, R.; Close, A.E.; Friedman, I.; Schwarcz, H.P.

1991-01-01

The eggshell of the African ostrich, Struthio camelus, closely approximates a closed system for the retention of indigenous proteinaceous residues. Epimerization of the protein amino acid isoleucine follows linear first-order kinetics in laboratory simulations nearly to racemic equilibrium, and the variation in D/L ratio within a single fragment, or between fragments of the same age, is significantly less than in other carbonate systems. These observations suggest that the extent of isoleucine epimerization (aIle/Ile ratio) in ostrich eggshell offers the potential for high-resolution geochronology of Quaternary deposits. From the simulation experiments, and dated early Holocene samples for which we have in situ mean annual sediment temperature measurements, Arrhenius parameters have been calculated; the activation energy is 30.33 kcal mol-1, similar to that of other carbonate systems. We have measured the aIle/Ile ratio in ostrich eggshell associated with lacustrine episodes at Bir Tarfawi and Bir Sahara East, two depressions in what is currently the hyperarid eastern Sahara. The ratios can be used directly to indicate qualitatively the time represented by each series of lake sediment, and to correlate disjunct lacustrine deposits within and between the basins. Uranium-series disequilibrium dating of algal mats contained within some of the lake beds indicate that a major wet interval occurred about 130 ka ago. Using the U-series date for calibration, the amino acid ratios are used to date the most recent lacustrine interval to about 100 ka B.P., and two older intervals, one about 200 ?? 25 ka B.P., and an older interval that occurred prior to 250 ka ago. ?? 1991.

Stratigraphic architecture of a fluvial-lacustrine basin-fill succession at Desolation Canyon, Uinta Basin, Utah: Reference to Walthers’ Law and implications for the petroleum industry

USGS Publications Warehouse

Ford, Grace L.; David R. Pyles,; Dechesne, Marieke

2016-01-01

Two large-scale (member-scale) upward patterns are noted: Waltherian, and non-Waltherian. The upward successions in Waltherian progressions record progradation or retrogradation of a linked fluvial-lacustrine system across the area; whereas the upward successions in non-Waltherian progressions record large-scale changes in the depositional system that are not related to progradation or retrogradation of the ancient lacustrine shoreline. Four Waltherian progressions are noted: 1) the Flagstaff Limestone to lower Wasatch Formation member records the upward transition from lacustrine to fluvial—or shallowing-upward succession; 2) the upper Wasatch to Uteland Butte records the upward transition from fluvial to lacustrine—or a deepening upward succession; 3) the Uteland Butte to Renegade Tongue records the upward transition from lacustrine to fluvial—a shallowing-upward succession; and 4) the Renegade Tongue to Mahogany oil shale interval records the upward transition from fluvial to lacustrine—a deepening upward succession. The two non-Waltherian progressions in the study area are: 1) the lower to middle Wasatch, which records the abrupt shift from low to high net-sand content fluvial system, and 2) the middle to upper Wasatch, which records the abrupt shift from high to intermediate net-sand content fluvial system.

Holocene environmental changes in northern Lebanon as inferred from a multiproxy study on lacustrine-palustrine sediment

NASA Astrophysics Data System (ADS)

Vidal, Laurence; Jenna, Hage-Hassen; Demory, François; Develle, Anne-Lise; van Campo, Elise; Elias, Ata

2016-04-01

The reconstruction of the Levantine post-glacial environmental evolution is essential to understand the interactions between variability of regional water cycle, dynamics of the global climate, and cultural evolution. We present a paleolacustrine record from the karstic Yammouneh basin (34.06N-34.09N; 36.0E-36.03E, 1360 m a.s.l.), located on the eastern flank of Mount Lebanon (northern Levant). Holocene sediments (retrieved from gully and a trenbch) (1.5 to 3.6 m thick) consist of pale lacustrine chalk interrupted by an ash layer and remarkable centimetric beds of ocher to dark brown silty clays used, in addition to 14C ages, as stratigraphical markers. Lacustrine biogenic remains are diversified and abundant (ostracods, gastropods, charophytes, chlorophyceae, plant debris…) all reflecting a freswater, generally shallow waterbody. We analysed the sediment mineralogy and geochemistry, TOM contents, magnetic properties, pollen and calcite oxygen isotope composition derived from ostracod shells. These sequences are compared to former data from 2 trenches and 1 core collected in different points of the basin (Daeron et al., 2007; Develle et al., 2009, 2010). A total of 42 AMS 14C dating (partly carbonized wood) provide a solid chronology from the YD to present. Results reveal the following main features : 1- intervals dominated by authigenic calcite suggest that the major water supply was the karstic springs, which still deliver Ca-rich water and low surface runoff; 2- the lake oxygen isotope composition has been impacted by the source isotope composition throughout the Holocene and by increased inland rainfall during the early Holocene; 3- a decideous oak forest, implying much more soil water availability than today, was developed around the lake from ca. 11.5 to 9.5 kyr (the very bad pollen preservation after 8.3 kyr reflects oxidation or frequent oscillations of the water level); 4- four paleosols evidenced from lithofacies and magnetic properties are identified

Platinum-nanoparticle-supported core-shell polymer nanospheres with unexpected water stability and facile further modification

NASA Astrophysics Data System (ADS)

Yuan, Conghui; Xu, Yiting; Luo, Weiang; Zeng, Birong; Qiu, Wuhui; Liu, Jie; Huang, Huiling; Dai, Lizong

2012-05-01

Core-shell nanospheres (CSNSs) with hydrophobic cores and hydrophilic shells were fabricated via a simple mini-emulsion polymerization for the stabilization of platinum nanoparticles (Pt-NPs). The CSNSs showed extremely high loading capacity of Pt-NPs (the largest loading amount of the Pt-NPs was about 49.2 wt%). Importantly, the Pt-NPs/CSNSs nanocomposites had unexpected stability in aqueous solution. DLS results revealed that the CSNSs loaded with Pt-NPs exhibited almost no aggregation after standing for a long time . However, the Pt-NPs immobilized on the CSNSs were not straitlaced: they could transport and redistribute between CSNSs freely when the environmental temperature was higher than the melting point of the CSNS shell. Owing to their excellent stability in aqueous solution, the surface of the Pt-NPs/CSNSs nanocomposites could be further decorated easily. For example, polyaniline (PANI)-coated Pt-NPs/CSNSs, nickel (Ni)-coated Pt-NPs/CSNSs and PANI/Pt-NPs dual-layer hollow nanospheres were facilely fabricated from the Pt-NPs/CSNS nanocomposites.

Sedimentology and Reservoir Characteristics of Early Cretaceous Fluvio-Deltaic and Lacustrine Deposits, Upper Abu Gabra Formation, Sufyan Sub-basin, Muglad Rift Basin, Sudan

NASA Astrophysics Data System (ADS)

Yassin, Mohamed; Abdullatif, Osman; Hariri, Mustafa

2017-04-01

Sufyan Sub-basin is an East-West trending Sub-basin located in the northwestern part of the Muglad Basin (Sudan), in the eastern extension of the West and Central Africa Rift System (WCARS). The Early Cretaceous Abu Gabra Formation considered as the main source rock in the Muglad Basin. In Sufyan Sub-basin the Early Cretaceous Upper Abu Gabra Formation is the main oil-producing reservoir. It is dominated by sandstone and shales deposited in fluvio-deltaic and lacustrine environment during the first rift cycle in the basin. Depositional and post-depositional processes highly influenced the reservoir quality and architecture. This study investigates different scales of reservoir heterogeneities from macro to micro scale. Subsurface facies analysis was analyzed based on the description of six conventional cores from two wells. Approaches include well log analysis, thin sections and scanning electron microscope (SEM) investigations, grain-size, and X-ray diffraction (XRD) analysis of the Abu Gabra sandstone. The cores and well logs analyses revealed six lithofacies representing fluvio-deltaic and lacustrine depositional environment. The sandstone is medium to coarse-grained, poorly to moderately sorted and sub-angular to subrounded, Sub-feldspathic arenite to quartz arenite. On macro-scale, reservoir quality varies within Abu Gabra reservoir where it shows progressive coarsening upward tendencies with different degrees of connectivity. The upper part of the reservoir showed well connected and amalgamated sandstone bodies, the middle to lower parts, however, have moderate to low sandstone bodies' connectivity and amalgamation. On micro-scale, sandstone reservoir quality is directly affected by textures and diagenesis.The XRD and SEM analyses show that kaolinite and chlorite clay are the common clay minerals in the studied samples. Clay matrix and quartz overgrowth have significantly reduced the reservoir porosity and permeability, while the dissolution of feldspars

Facile in situ synthesis of wurtzite ZnS/ZnO core/shell heterostructure with highly efficient visible-light photocatalytic activity and photostability

NASA Astrophysics Data System (ADS)

Xiao, Jian-Hua; Huang, Wei-Qing; Hu, Yong-sheng; Zeng, Fan; Huang, Qin-Yi; Zhou, Bing-Xin; Pan, Anlian; Li, Kai; Huang, Gui-Fang

2018-02-01

High photocatalytic activity and photostability are the pursuit of the goal for designing promising photocatalysts. Herein, using ZnO to encapsulate ZnS nanoparticles is proposed as an effective strategy to enhance photocatalytic activity and anti-photocorrosion. The ZnS/ZnO core/shell heterostructures are obtained via an annealing treatment of ZnS nanoparticles produced by a facile wet chemical approach. Due to its small size, the nascent cubic sphalerite ZnS (s-ZnS) converts into a hexagonal wurtzite ZnS (w-ZnS)/ZnO core/shell structure after annealing treatment. In situ oxidation leads to increasing ZnO, simultaneously decreasing the w-ZnS content in the resultant w-ZnS/ZnO with thermal annealing time. The w-ZnS/ZnO core/shell heterostructures show high photocatalytic activity, demonstrated by the photodegradation rate of methylene blue being up to ten-fold and seven-fold higher than that of s-ZnS under UV and visible light irradiation, respectively, and the high capability of degrading rhodamine B. The enhanced photocatalytic activity may be attributed to the large specific surface and improved charge carrier separation at the core/shell interface. Moreover, it displays high photostability owing to the protection of the ZnO shell, greatly inhibiting the photocorrosion of ZnS. This facile in situ oxidation is effective and easily scalable, providing opportunities for developing novel core/shell structure photocatalysts with high activity and photostability.

Climatic and lacustrine morphometric controls of diatom paleoproductivity in a tropical Andean lake

NASA Astrophysics Data System (ADS)

Bao, R.; Hernández, A.; Sáez, A.; Giralt, S.; Prego, R.; Pueyo, J. J.; Moreno, A.; Valero-Garcés, B. L.

2015-12-01

The coupling of lake dynamics with catchment biogeochemistry is considered the key element controlling primary production in mountain lakes at time scales of a few decades to millennia, yet little is known on the impacts of the morphometry of lakes throughout their ontogeny. As Lake Chungará (Central Andean Altiplano, northern Chile) experienced long-term lake-level fluctuations that strongly modified its area:volume ratio, it is an ideal system for exploring the relative roles that long-term climatic shifts and lake morphometry play on biosiliceous lacustrine productivity. In this paper, we review previous data on the percent contents of total organic carbon, total inorganic carbon, total nitrogen, total biogenic silica, isotopic composition of organic matter, carbonates, and diatom frustules, as well as data on the abundance of the chlorophycean Botryococcus braunii in this lake for the period 12,400-1300 cal yr BP. We also include new data on organic carbon and biogenic silica mass accumulation rates and the diatom assemblage composition of an offshore core dated using 14C and U/Th. Biosiliceous productivity in Lake Chungará was influenced by shifts in allochthonous nutrient inputs related to variability in precipitation. Humid phases dated at approx. 12,400 to 10,000 and 9600 to 7400 cal yr BP coincide with periods of elevated productivity, whereas decreases in productivity were recorded during arid phases dated at approx. 10,000 to 9600 and 7400 to 3550 cal yr BP (Andean mid-Holocene Aridity Period). However, morphometry-related in-lake controls led to a lack of a linear response of productivity to precipitation variability. During the late Glacial to early Holocene, lowstands facilitated complete water column mixing, prompting episodic massive blooms of a large centric diatom, Cyclostephanos cf. andinus. Thus, moderate productivity could be maintained, regardless of aridity, by this phenomenon of morphometric eutrophy during the early history of the lake

Facile preparation of magnetic metal organic frameworks core-shell nanoparticles for stimuli-responsive drug carrier

NASA Astrophysics Data System (ADS)

Li, Sheng; Bi, Ke; Xiao, Ling; Shi, Xiaowen

2017-12-01

Facile synthesis of core-shell magnetic MOFs for drug delivery is of significance due to the advantages of high drug load and easy separation. In this work, magnetic metal organic frameworks (MOFs, Fe3O4-NH2@MIL101-NH2) core-shell nanoparticles were synthesized rapidly in water phase by microwave irradiation using Fe3+ and 2-amino-1,4-benzenedicarboxylate (BDC-NH2) as metal ions and ligands respectively. The resulting magnetic MOFs exhibit large surface areas (96.04 m2 g-1), excellent magnetic response (20.47 emu g-1) and large mesopore volume (22.07 cm3 g-1) along with spherical morphologies with the diameters ranging from 140-330 nm. Using doxorubicin (DOX) as a model drug, the drug loading capacity of Fe3O4-NH2@MIL101-NH2 could reach 36.02%, substantially higher than pristine MIL101-NH2. Importantly, the release of DOX could be controlled by pH as well as the meso pore size of MOFs. The cytotoxicity assay showed that the magnetic MOFs have low cytotoxicity and good biocompatibility. The results suggest great potential of the magnetic MOFs core-shell nanoparticles fabricated in this study on controlled drug release of DOX.

Facile preparation of magnetic metal organic frameworks core-shell nanoparticles for stimuli-responsive drug carrier.

PubMed

Li, Sheng; Bi, Ke; Xiao, Ling; Shi, Xiaowen

2017-12-08

Facile synthesis of core-shell magnetic MOFs for drug delivery is of significance due to the advantages of high drug load and easy separation. In this work, magnetic metal organic frameworks (MOFs, Fe 3 O 4 -NH 2 @MIL101-NH 2 ) core-shell nanoparticles were synthesized rapidly in water phase by microwave irradiation using Fe 3+ and 2-amino-1,4-benzenedicarboxylate (BDC-NH 2 ) as metal ions and ligands respectively. The resulting magnetic MOFs exhibit large surface areas (96.04 m 2 g -1 ), excellent magnetic response (20.47 emu g -1 ) and large mesopore volume (22.07 cm 3 g -1 ) along with spherical morphologies with the diameters ranging from 140-330 nm. Using doxorubicin (DOX) as a model drug, the drug loading capacity of Fe 3 O 4 -NH 2 @MIL101-NH 2 could reach 36.02%, substantially higher than pristine MIL101-NH 2 . Importantly, the release of DOX could be controlled by pH as well as the meso pore size of MOFs. The cytotoxicity assay showed that the magnetic MOFs have low cytotoxicity and good biocompatibility. The results suggest great potential of the magnetic MOFs core-shell nanoparticles fabricated in this study on controlled drug release of DOX.

A 400-year phytolith-based reconstruction of wild rice (Zizania palustris) abundance from Mud Lake core sediments, Fond du Lac Band of Lake Superior Chippewa Reservation, Minnesota, USA.

NASA Astrophysics Data System (ADS)

Munoz, R.; Caylor, E.; Yost, C. L.; Drake, C.; Ladwig, J. L.; Myrbo, A.; Howes, T.

2014-12-01

Wild rice (Zizania palustris L.) is an aquatic grass with spiritual and subsistence significance to Native people of the Great Lakes region of North America. Mud Lake (Mashkiigwaagamaag), located on the Fond du Lac Band of Lake Superior Chippewa Reservation in Carlton County, Minnesota, USA, once supported an extensive population of wild rice (manoomin). However, early 20th century attempts to ditch and drain surrounding wetlands for landuse intensification severely altered the natural hydrological system that supports wild rice. Fond du Lac Resource Management (FDLRM) technicians are currently working to increase the wild rice population in Mud Lake. As part of these efforts, this phytolith study was undertaken to better understand how wild rice abundance has fluctuated over the past 400 years, with particular emphasis on the 19th and 20th centuries. Phytoliths are microscopic opal silica plant remains that are incorporated into soils and lake sediments after the plant-parts that contain them decay. Wild rice produces phytolith morphotypes that are unequivocally diagnostic. Mud Lake core MNMN-MUD11-1C-1P-1 (46°43'38.39"N, 92°42'2.45"W) was piston cored by LacCore (National Lacustrine Core Facility) and FDLRM technicians on 24 May 2011. Initial core descriptions, multi-sensor core logging, phytolith sampling and phytolith extractions were completed during the summer of 2014 at LacCore. Wild rice phytolith identification and quantification was conducted on twelve samples using brightfield microscopy at 400x magnification. Wild rice phytolith concentration values ranged from 68 to 2,300 phytoliths/cm3. Wild rice accumulation rates ranged from 9 to 383 phytoliths/ cm2/yr, peaking in 1952 AD. Wild rice abundance in Mud Lake appears to be influenced by a complex set of variables that include anthropogenic disturbance, climatic events and aquatic plant community succession.

U.S. National Institutes of Health core consolidation-investing in greater efficiency.

PubMed

Chang, Michael C; Birken, Steven; Grieder, Franziska; Anderson, James

2015-04-01

The U.S. National Institutes of Health (NIH) invests substantial resources in core research facilities (cores) that support research by providing advanced technologies and scientific and technical expertise as a shared resource. In 2010, the NIH issued an initiative to consolidate multiple core facilities into a single, more efficient core. Twenty-six institutions were awarded supplements to consolidate a number of similar core facilities. Although this approach may not work for all core settings, this effort resulted in consolidated cores that were more efficient and of greater benefit to investigators. The improvements in core operations resulted in both increased services and more core users through installation of advanced instrumentation, access to higher levels of management expertise; integration of information management and data systems; and consolidation of billing; purchasing, scheduling, and tracking services. Cost recovery to support core operations also benefitted from the consolidation effort, in some cases severalfold. In conclusion, this program of core consolidation resulted in improvements in the effective operation of core facilities, benefiting both investigators and their supporting institutions.

Palaeoenvironmental implications of a Holocene sequence of lacustrine-peat sediments from the desert-loess transitional zone in Northern China

NASA Astrophysics Data System (ADS)

Jia, Feifei; Lu, Ruijie; Liu, Xiaokang; Zhao, Chao; Lv, Zhiqiang; Gao, Shangyu

2018-05-01

A high-resolution lacustrine-peat record from the desert-loess transitional zone in Northern China was obtained to reconstruct Holocene environmental change in the region. AMS 14C dates are used to provide a chronology. The results indicate that the site was a desert environment before 12.2 cal kyr BP, and was then occupied by a paleolake which started to shrink, with a wetland occurring from 6.2 to 3.0 cal kyr BP. Subsequently, the site became a seasonally water-filled depression. Based on the lithology and measurements of grain size and total organic carbon content, the climate changed from arid to humid at 12.2 cal kyr BP, and became more humid after 8.3 cal kyr BP. From 6.2 to 3.0 cal kyr BP, precipitation decreased but the climate remained at an optimum. After 3.0 cal kyr BP, the climate was dry overall but with several humid intervals. A comparison of paleoclimatic records from lacustrine and aeolian deposits from the region reveals a discrepancy about the nature of the early Holocene climate, and we conclude that this is because lacustrine sediments responded more sensitively to precipitation than aeolian deposits when the temperature was low. The environmental evolution of the region was synchronous with changes in the Asian summer monsoon (ASM), but temperature also played a key role in the early Holocene.

Advanced light microscopy core facilities: Balancing service, science and career

PubMed Central

Hartmann, Hella; Reymann, Jürgen; Ansari, Nariman; Utz, Nadine; Fried, Hans‐Ulrich; Kukat, Christian; Peychl, Jan; Liebig, Christian; Terjung, Stefan; Laketa, Vibor; Sporbert, Anje; Weidtkamp‐Peters, Stefanie; Schauss, Astrid; Zuschratter, Werner; Avilov, Sergiy

2016-01-01

ABSTRACT Core Facilities (CF) for advanced light microscopy (ALM) have become indispensable support units for research in the life sciences. Their organizational structure and technical characteristics are quite diverse, although the tasks they pursue and the services they offer are similar. Therefore, throughout Europe, scientists from ALM‐CFs are forming networks to promote interactions and discuss best practice models. Here, we present recommendations for ALM‐CF operations elaborated by the workgroups of the German network of ALM‐CFs, German Bio‐Imaging (GerBI). We address technical aspects of CF planning and instrument maintainance, give advice on the organization and management of an ALM‐CF, propose a scheme for the training of CF users, and provide an overview of current resources for image processing and analysis. Further, we elaborate on the new challenges and opportunities for professional development and careers created by CFs. While some information specifically refers to the German academic system, most of the content of this article is of general interest for CFs in the life sciences. Microsc. Res. Tech. 79:463–479, 2016. © 2016 THE AUTHORS MICROSCOPY RESEARCH AND TECHNIQUE PUBLISHED BY WILEY PERIODICALS, INC. PMID:27040755

RADIATION FACILITY FOR NUCLEAR REACTORS

DOEpatents

Currier, E.L. Jr.; Nicklas, J.H.

1961-12-12

A radiation facility is designed for irradiating samples in close proximity to the core of a nuclear reactor. The facility comprises essentially a tubular member extending through the biological shield of the reactor and containing a manipulatable rod having the sample carrier at its inner end, the carrier being longitudinally movable from a position in close proximity to the reactor core to a position between the inner and outer faces of the shield. Shield plugs are provided within the tubular member to prevent direct radiation from the core emanating therethrough. In this device, samples may be inserted or removed during normal operation of the reactor without exposing personnel to direct radiation from the reactor core. A storage chamber is also provided within the radiation facility to contain an irradiated sample during the period of time required to reduce the radioactivity enough to permit removal of the sample for external handling. (AEC)

Facile deposition of gold nanoparticles on core-shell Fe3O4@polydopamine as recyclable nanocatalyst

NASA Astrophysics Data System (ADS)

Zhao, Yan; Yeh, Yaowen; Liu, Rui; You, Jinmao; Qu, Fengli

2015-07-01

A simple and green method for the controllable synthesis of core-shell Fe3O4 polydopamine nanoparticles (Fe3O4@PDA NPs) with tunable shell thickness and their application as a recyclable nanocatalyst support is presented. Magnetite Fe3O4 NPs formed in a one-pot process by the hydrothermal approach with a diameter of ˜240 nm were coated with a polydopamine shell layer with a tunable thickness of 15-45 nm. The facile deposition of Au NPs atop Fe3O4@PDA NPs was achieved by utilizing PDA as both the reducing agent and the coupling agent. The satellite nanocatalysts exhibited high catalytic performance for the reduction of p-nitrophenol. Furthermore, the recovery and reuse of the catalyst was demonstrated 8 times without detectible loss in activity. The synergistic combination of unique features of PDA and magnetic nanoparticles establishes these core-shell NPs as a versatile platform for potential applications.

Core commands across airway facilities systems.

DOT National Transportation Integrated Search

2003-05-01

This study takes a high-level approach to evaluate computer systems without regard to the specific method of : interaction. This document analyzes the commands that Airway Facilities (AF) use across different systems and : the meanings attributed to ...

Paleontological analysis of a lacustrine carbonaceous uranium deposit at the Anderson mine, Date Creek basin, west-central Arizona (U.S.A.)

USGS Publications Warehouse

Otton, J.K.; Bradbury, J.P.; Forester, R.M.; Hanley, J.H.

1990-01-01

The Tertiary sedimentary sequence of the Date Creek basin area of Arizona is composed principally of intertonguing alluvial-fan and lacustrine deposits. The lacustrine rocks contain large intermediate- to, locally, high-grade uranium deposits that form one of the largest uranium resources in the United States (an estimated 670,000 tons of U3O8 at an average grade of 0.023% is indicated by drilling to date). At the Anderson mine, about 50,000 tons of U3O8 occurs in lacustrine carbonaceous siltstones and mudstones (using a cutoff grade of 0.01%). The Anderson mine constitutes a new class of ore deposit, a lacustrine carbonaceous uranium deposit. Floral and faunal remains at the Anderson mine played a critical role in creating and documenting conditions necessary for uranium mineralization. Organic-rich, uraniferous rocks at the Anderson mine contain plant remains and ostracodes having remarkably detailed preservation of internal features because of infilling by opaline silica. This preservation suggests that the alkaline lake waters in the mine area contained high concentrations of dissolved silica and that silicification occurred rapidly, before compaction or cementation of the enclosing sediment. Uranium coprecipitated with the silica. Thinly laminated, dark-colored, siliceous beds contain centric diatoms preserved with carbonaceous material suggesting that lake waters at the mine were locally deep and anoxic. These alkaline, silica-charged waters and a stagnant, anoxic environment in parts of the lake were necessary conditions for the precipitation of large amounts of uranium in the lake-bottom sediments. Sediments at the Anderson mine contain plant remains and pollen that were derived from diverse vegetative zones suggesting about 1500 m of relief in the area at the time of deposition. The pollen suggests that the valley floor was semiarid and subtropical, whereas nearby mountains supported temperate deciduous forests. ?? 1990.

The pre-spawning migratory behaviour of Atlantic salmon Salmo salar in a large lacustrine catchment.

PubMed

Kennedy, R J; Allen, M

2016-09-01

The movements of adult Atlantic salmon Salmo salar were determined as they migrated to spawning habitats in a large lacustrine catchment, Lough Neagh, in Northern Ireland. The minimum average ground speed of S. salar through the lake was 2·1 km day(-1) and the mean residence time was 11 days. Tagged S. salar tended to actively migrate through the lake which represented a transitory habitat for adult S. salar. Migration time from the release site, through the lake, to a spawning tributary decreased during the migratory period. During the 4 year study period between 20·5 and 41·6% of tagged S. salar which entered the lake each year, explored at least one other channel before ascending the final spawning tributary. Exploratory behaviour was more likely in S. salar which spawned in the tributaries furthest from the sea. Exploratory behaviour was also more likely to occur during periods of reduced discharge in the natal stream. The fishery management implications of complex pre-spawning behaviour in a mixed stock lacustrine system, are discussed. © 2016 The Fisheries Society of the British Isles.

Outreach, Diversity, and Education Supported by NSF Facilities LacCore and the Continental Scientific Drilling Coordination Office (CSDCO), University of Minnesota

NASA Astrophysics Data System (ADS)

Myrbo, A.

2015-12-01

Climatic and environmental change are a powerful hook to engage students and the public with geoscience. Recent lake sediments often feature visual and compositional evidence of anthropogenic changes, which can pique curiosity and serve as a gateway for interest in more remote past changes. Cores provide an integrative, place-based geoscience education/outreach platform: lake dynamics incorporate principles of chemistry, physics, and biology; lake basin formation and sedimentary signals trace back to numerous geoscience subdisciplines. Lakes reflect local changes, and so are inherently place-based and relevant to both rural and urban populations. The esthetics of lakes in the landscape and sediments under the microscope spark the artistic sensibilities of those who do not consider themselves scientists: lakes are readymade for STEAM education. LacCore has exploited the magic of lake sediment cores in its 15 years as an NSF Facility, and now expands to additional environments as the NSF Continental Scientific Drilling Coordination Office. Part of scaling up is the formalization of major support for the Broader Impacts (BI) activities of Facility users. LacCore/CSDCO now musters its collaborative experiences in site REUs and other undergrad research projects, in-depth training of students, teachers, and faculty, a long list of informal education experiences, and common-good software development, to provide assistance to researchers seeking meaningful broader impacts and educators seeking extra- or co-curricular field and laboratory research experiences for their students. Outreach, diversity, and education support includes dissemination of best practices, as well as coordination, administration, and basic capacity for such activities in collaboration with project PIs and students, through no-cost support, or collaborative proposals or supplements from NSF where necessary for project scale. Community-driven research and broadening participation are central to the

A Habitable Fluvio-Lacustrine Environment at Yellowknife Bay, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Grotzinger, J. P.; Sumner, D. Y.; Kah, L. C.; Stack, K.; Gupta, S.; Edgar, L.; Rubin, D.; Lewis, K.; Schieber, J.; Mangold, N.;

A habitable fluvio-lacustrine environment at Yellowknife Bay, Gale crater, Mars.

PubMed

Grotzinger, J P; Sumner, D Y; Kah, L C; Stack, K; Gupta, S; Edgar, L; Rubin, D; Lewis, K; Schieber, J; Mangold, N; Milliken, R; Conrad, P G; DesMarais, D; Farmer, J; Siebach, K; Calef, F; Hurowitz, J; McLennan, S M; Ming, D; Vaniman, D; Crisp, J; Vasavada, A; Edgett, K S; Malin, M; Blake, D; Gellert, R; Mahaffy, P; Wiens, R C; Maurice, S; Grant, J A; Wilson, S; Anderson, R C; Beegle, L; Arvidson, R; Hallet, B; Sletten, R S; Rice, M; Bell, J; Griffes, J; Ehlmann, B; Anderson, R B; Bristow, T F; Dietrich, W E; Dromart, G; Eigenbrode, J; Fraeman, A; Hardgrove, C; Herkenhoff, K; Jandura, L; Kocurek, G; Lee, S; Leshin, L A; Leveille, R; Limonadi, D; Maki, J; McCloskey, S; Meyer, M; Minitti, M; Newsom, H; Oehler, D; Okon, A; Palucis, M; Parker, T; Rowland, S; Schmidt, M; Squyres, S; Steele, A; Stolper, E; Summons, R; Treiman, A; Williams, R; Yingst, A

2014-01-24

The Curiosity rover discovered fine-grained sedimentary rocks, which are inferred to represent an ancient lake and preserve evidence of an environment that would have been suited to support a martian biosphere founded on chemolithoautotrophy. This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species. Carbon, hydrogen, oxygen, sulfur, nitrogen, and phosphorus were measured directly as key biogenic elements; by inference, phosphorus is assumed to have been available. The environment probably had a minimum duration of hundreds to tens of thousands of years. These results highlight the biological viability of fluvial-lacustrine environments in the post-Noachian history of Mars.

The Inception of the Colorado Plateau Coring Project: Filling the Triassic Geochronologic Gap and Providing a Continuous Record of Continental Environmental Change in Western Equatorial Pangea

NASA Astrophysics Data System (ADS)

Geissman, J. W.; Olsen, P. E.; Kent, D. V.; Irmis, R. B.; Gehrels, G. E.; Mundil, R.; Parker, W.; Bachmann, G. H.; Kurschner, W. M.; Sha, J.

2014-12-01

The Triassic Period was punctuated by two of the largest Phanerozoic mass-extinctions and witnessed the evolution of elements of the modern biota and the advent of the age of dinosaurs. A rich archive of biotic and environmental changes on land for the early Mesozoic is on the Colorado Plateau, which despite over 100 years of study still remains poorly calibrated in time and poorly registered to other global records. Over 15 years ago, a diverse team of scientists began to develop the concept of a multi-phase, long term Colorado Plateau Coring Project (CPCP). Planning involved two major meetings (DOSECC/NSFICDP supported in Fall, 2007, St. George, UT; and International Continental Drilling Program (ICDP) supported in Spring, 2009, Albuquerque, NM). The National Park Service embraced the concept of Phase One drilling at Petrified Forest National Park (PFNP) in northern Arizona, which exposes one of the most famous and best studied successions of the continental Triassic on Earth, and the Phase One target was decided. Most drilling operation costs were secured from ICDP in Summer, 2010. In late 2013, following more recent NSF support, the research team, utilizing Ruen Drilling Inc., drilled a continuous ~530 m core (60o plunge) through the entire section of Triassic strata (Chinle and Moenkopi fms.) in the north end and a ~240 m core (75o plunge) in lower Chinle and all Moenkopi strata at the south end of the PFNP. Our continuous sampling will place this record in a reliable quantitative and exportable time scale, as a reference section in which magnetostratigraphic, geochronologic, environmental, and paleontologic data are registered to a common thickness scale with unambiguous superposition using pristine samples. The cores are being scanned at the High Resolution X-ray Computed Tomography Facility at UT Austin. They will be transported to the LacCore National Lacustrine Core Facility at U Minnesota, where they will be split, imaged, and scanned for several

Alluvial to lacustrine sedimentation in an endorheic basin during the Mio-Pliocene: The Toro Negro Formation, Central Andes of Argentina

NASA Astrophysics Data System (ADS)

Ciccioli, Patricia L.; Marenssi, Sergio A.; Amidon, William H.; Limarino, Carlos O.; Kylander-Clark, Andrew

2018-07-01

A 2400 m-thick sedimentary column belonging to the Toro Negro Formation was recorded along the Quebrada del Yeso, Sierra de Los Colorados (Vinchina Basin), La Rioja province, NW Argentina. The Vinchina basin is a good example of a closed basin surrounded by the Precordillera fold and thrust belt to the west and basement-cored blocks to the north, south (Western Sierras Pampeanas) and east (Sierra de Famatina). Seven facies associations (FA) are described and interpreted to represent fluvial, lacustrine and alluvial environments developed in the southern part of the Vinchina basin from the Late Miocene until the earliest Pleistocene. The depositional evolution of the formation was divided in four phases. Phase I (∼7-6.6 Ma) represents sedimentation in medial (FA I) to distal (FA II) parts of a southward directed distributive fluvial system with a retrogradational pattern. During phase II (6.6-6.1Ma), the distributive fluvial system was replaced by a mixed clastic-evaporitic shallow lake (FA III) in a high aggradational basin. In phase III (∼6.1-5 Ma) the eastward progradation of a fluvial system (FA IV) was recorded as a distal clastic wedge. Finally, phase IV (∼5-2.4Ma) records two depositional cycles of proximal clastic wedge progradation of fluvial-dominated piedmonts (FAV, FAVII) from the southwest (Sierra de Umango) and/or the west (Precordillera) with an intervening playa lake (FA VI). Two new U-Pb ages obtained from zircons in volcanic ash layers confirm the Late Miocene age of the lower member of the Toro Negro Formation and permit a tight correlation with the central part of the basin (Quebrada de La Troya section). The sedimentation rate calculated for the dated lacustrine-fluvial interval is higher than the corresponding one in La Troya area suggesting a higher subsidence in the southern part of the basin. During the Late Miocene (∼7-6.6Ma) the ephemeral drainage was controlled by an arid to semiarid climate and initially dissipated mostly

Holocene environmental changes in northern Lebanon as inferred from a multiproxy study on lacustrine-palustrine sediment

NASA Astrophysics Data System (ADS)

Vidal, L.; Hage-Hassan, J.; Gasse, F. A.; Demory, F.; van Campo, E.; Develle, A.; Elias, A.

2013-12-01

The reconstruction of the Levantine post-glacial environmental evolution is essential to understand the interactions between variability of regional water cycle, dynamics of the global climate, and cultural evolution. Here, we present an Holocene record from the karstic Yammouneh basin (34.06N-34.09N; 36.0E-36.03E, 1360 m a.s.l.), located on the eastern flank of Mount Lebanon (northern Levant). Two new sedimentary profiles (from 1 gully and 1 trench) complement former data from 2 trenches and 1 core collected in different points of the basin (Daeron et al., 2007; Develle et al., 2009, 2010). A total of 42 AMS 14C dating (partly carbonized wood) provide a solid chronology from the YD to present. Holocene sediments (1.5 to 3.6 m thick) consist of pale lacustrine chalk interrupted by an ash layer and remarkable centimetric beds of ocher to dark brown silty clays used, in addition to 14C ages, as stratigraphical markers. Lacustrine biogenic remains are diversified and abundant (ostracods, gastropods, charophytes, chlorophyceae, plant debris...) all reflecting a freswater, generally shallow waterbody. We analysed the sediment mineralogy, TOM contents, magnetic properties (magnetic susceptibility and its frequency dependence), pollen and calcite oxygen isotope composition derived from ostracod shells. Results reveal the following main features : 1- intervals dominated by authigenic calcite suggest that the major water supply was the karstic springs, which still deliver Ca-rich water and low surface runoff; 2- the lake oxygen isotope composition has been impacted by the source isotope composition throughout the Holocene and by increased inland rainfall during the early Holocene; 3- a decideous oak forest, implying much more soil water availability than today, was developed around the lake from ca. 11.5 to 9.5 kyr (the very bad pollen preservation after 8.3 kyr reflects oxidation or frequent oscillations of the water level); 4- four paleosols evidenced from lithofacies and

Ecological state of the Romanian Black Sea littoral lacustrine ecosystems

NASA Astrophysics Data System (ADS)

Gomoiu, M.-T.

2009-04-01

The author uses the results of his own researches as well as data from specialty literature to assess the ecological state of some typical lacustrine ecosystems considered, about 50 years ago, of major importance by their functions, services and researches, for the human populations in the settlements nearby. Based on this assessment the author recommends a few criteria which can be taken into account when programs of integrated management of these coastal ecosystems are initiated. The paper focuses on the study cases regarding the following major ecosystems: 1. Razelm-Sinoie Lagoon Complex - tightly linked to the Danube River and Delta systems, 2. Taşaul Lake - interfered in the last two decades by a branch of the DanubeRiver - Black Sea Canal and 3. Techirghiol Lake - for a long time under the sea level, a hyperhaline lake with therapeutic, sapropelic mud, disturbed by huge quantities of freshwaters infiltrated from the irrigation system. At present, the state of the lacustrine ecosystems at the Romanian Black Sea Coast can be characterized, mainly, by the following aspects: · Increase in the quantities of nutrients and chemical toxicants; · Rise in the level and frequency of eutrophication and pollution phenomena; · Drastic reduction of specific diversity; · Simplification of communities' structure - biocoenosis homogeneity; · Decrease in numerical abundance and biomass of benthic populations and consequently, low biofilter power by the decrease of the filter-feeder populations; · Worsening of the qualitative and the quantitative state of the biological benthic resources; · Thriving opportunistic forms (e.g. the worms causing sediment bioturbation); · Invasion by some exotic species, with harmful, unexpected consequences; · All populations undergo quantitative fluctuations; · Decrease in the fish population and in the use values of lacustrine assets, with strong impact on the welfare of the human society. Almost all pressure forms associated with the

Advanced light microscopy core facilities: Balancing service, science and career.

PubMed

Ferrando-May, Elisa; Hartmann, Hella; Reymann, Jürgen; Ansari, Nariman; Utz, Nadine; Fried, Hans-Ulrich; Kukat, Christian; Peychl, Jan; Liebig, Christian; Terjung, Stefan; Laketa, Vibor; Sporbert, Anje; Weidtkamp-Peters, Stefanie; Schauss, Astrid; Zuschratter, Werner; Avilov, Sergiy

2016-06-01

Core Facilities (CF) for advanced light microscopy (ALM) have become indispensable support units for research in the life sciences. Their organizational structure and technical characteristics are quite diverse, although the tasks they pursue and the services they offer are similar. Therefore, throughout Europe, scientists from ALM-CFs are forming networks to promote interactions and discuss best practice models. Here, we present recommendations for ALM-CF operations elaborated by the workgroups of the German network of ALM-CFs, German Bio-Imaging (GerBI). We address technical aspects of CF planning and instrument maintainance, give advice on the organization and management of an ALM-CF, propose a scheme for the training of CF users, and provide an overview of current resources for image processing and analysis. Further, we elaborate on the new challenges and opportunities for professional development and careers created by CFs. While some information specifically refers to the German academic system, most of the content of this article is of general interest for CFs in the life sciences. Microsc. Res. Tech. 79:463-479, 2016. © 2016 THE AUTHORS MICROSCOPY RESEARCH AND TECHNIQUE PUBLISHED BY WILEY PERIODICALS, INC. © 2016 The Authors Microscopy Research and Technique Published by Wiley Periodicals, Inc.

Sedimentary and tectonic evolution of Plio Pleistocene alluvial and lacustrine deposits of Fucino Basin (central Italy)

NASA Astrophysics Data System (ADS)

Cavinato, Gian Paolo; Carusi, Claudio; Dall'Asta, Massimo; Miccadei, Enrico; Piacentini, Tommaso

2002-04-01

The Fucino Basin was the greatest lake of the central Italy, which was completely drained at the end of 19th century. The basin is an intramontane half-graben filled by Plio-Quaternary alluvial and lacustrine deposits located in the central part of the Apennines chain, which was formed in Upper Pliocene and in Quaternary time by the extensional tectonic activity. The analysis of the geological surface data allows the definition of several stratigraphic units grouped in Lower Units and Upper Units. The Lower Units (Upper Pliocene) are exposed along the northern and north-eastern basin margins. They consist of open to marginal lacustrine deposits, breccia deposits and fluvial deposits. The Upper Units (Lower Pliocene-Holocene) consist of interbedded marginal lacustrine deposits and fluvial deposits; thick coarse-grained fan-delta deposits are interfingered at the foot of the main relief with fluvial-lacustrine deposits. Most of the thickness of the lacustrine sequences (more than 1000-m thick) is buried below the central part of the Fucino Plain. The basin is bounded by E-W, WSW-ENE and NW-SE fault systems: Velino-Magnola Fault (E-W) and Tremonti-Celano-Aielli Fault (WSW-ENE) and S. Potito-Celano Fault (NW-SE) in the north; the Trasacco Fault, the Pescina-Celano Fault and the Serrone Fault (NW-SE) in the south-east. The geometry and kinematic indicators of these faults indicate normal or oblique movements. The study of industrial seismic profiles across the Fucino Basin gives a clear picture of the subsurface basin geometry; the basin shows triangular-shaped basin-fill geometry, with the maximum deposits thickness toward the main east boundary fault zones that dip south-westward (Serrone Fault, Trasacco Fault, Pescina-Celano Fault). On the basis of geological surface data, borehole stratigraphy and seismic data analysis, it is possible to recognize and to correlate sedimentary and seismic facies. The bottom of the basin is well recognized in the seismic lines

Alleviation of Facility/Engine Interactions in an Open-Jet Scramjet Test Facility

NASA Technical Reports Server (NTRS)

Albertson, Cindy W.; Emami, Saied

2001-01-01

Results of a series of shakedown tests to eliminate facility/engine interactions in an open-jet scramjet test facility are presented. The tests were conducted with the NASA DFX (Dual-Fuel eXperimental scramjet) engine in the NASA Langley Combustion Heated Scramjet Test Facility (CHSTF) in support of the Hyper-X program, The majority of the tests were conducted at a total enthalpy and pressure corresponding to Mach 5 flight at a dynamic pressure of 734 psf. The DFX is the largest engine ever tested in the CHSTF. Blockage, in terms of the projected engine area relative to the nozzle exit area, is 81% with the engine forebody leading edge aligned with the upper edge of the facility nozzle such that it ingests the nozzle boundary layer. The blockage increases to 95% with the engine forebody leading edge positioned 2 in. down in the core flow. Previous engines successfully tested in the CHSTF have had blockages of no more than 51%. Oil flow studies along with facility and engine pressure measurements were used to define flow behavior. These results guided modifications to existing aeroappliances and the design of new aeroappliances. These changes allowed fueled tests to be conducted without facility interaction effects in the data with the engine forebody leading edge positioned to ingest the facility nozzle boundary layer. Interaction effects were also reduced for tests with the engine forebody leading edge positioned 2 in. into the core flow, however some interaction effects were still evident in the engine data. A new shroud and diffuser have been designed with the goal of allowing fueled tests to be conducted with the engine forebody leading edge positioned in the core without facility interaction effects in the data. Evaluation tests of the new shroud and diffuser will be conducted once ongoing fueled engine tests have been completed.

BIOLOGICAL IRRADIATION FACILITY

DOEpatents

McCorkle, W.H.; Cern, H.S.

1962-04-24

A facility for irradiating biological specimens with neutrons is described. It includes a reactor wherein the core is off center in a reflector. A high-exposure room is located outside the reactor on the side nearest the core while a low-exposure room is located on the opposite side. Means for converting thermal neutrons to fast neutrons are movably disposed between the reactor core and the high and low-exposure rooms. (AEC)

Earthquake imprints on a lacustrine deltaic system: the Kürk Delta along the East Anatolian Fault (Turkey)

NASA Astrophysics Data System (ADS)

Hubert-Ferrari, Aurélia; El-Ouahabi, Meriam; Garcia-Moreno, David; Avsar, Ulas; Altinok, Sevgi; Schmidt, Sabine; Cagatay, Namik

2016-04-01

Delta contains a sedimentary record primarily indicative of water level changes, but particularly sensitive to earthquake shaking, which results generally in soft-sediment-deformation structures. The Kürk Delta adjacent to a major strike-slip fault displays this type of deformation (Hempton and Dewey, 1983) as well as other types of earthquake fingerprints that are specifically investigated. This lacustrine delta stands at the south-western extremity of the Hazar Lake and is bound by the East Anatolian Fault (EAF), which generated earthquakes of magnitude 7 in eastern Turkey. Water level changes and earthquake shaking affecting the Kurk Delta have been reevaluated combining geophysical data (seismic-reflection profiles and side-scan sonar), remote sensing images, historical data, onland outcrops and offshore coring. The history of water level changes provides a temporal framework regarding the sedimentological record. In addition to the commonly soft-sediment-deformation previously documented, the onland outcrops reveal a record of deformation (faults and clastic dykes) linked to large earthquake-induced liquefactions. The recurrent liquefaction structures can be used to obtain a paleoseismological record. Five event horizons were identified that could be linked to historical earthquakes occurring in the last 1000 years along the EAF. Sedimentary cores sampling the most recent subaqueous sedimentation revealed the occurrence of another type of earthquake fingerprint. Based on radionuclide dating (137Cs and 210Pb), two major sedimentary events were attributed to the 1874-1875 earthquake sequence along the EAF. Their sedimentological characteristics were inferred based X-ray imagery, XRD, LOI, grain-size distribution, geophysical measurements. The events are interpreted to be hyperpycnal deposits linked to post-seismic sediment reworking of earthquake-triggered landslides. A time constraint regarding this sediment remobilization process could be achieved thanks to

Lacustrine flow (divers, side scan sonar, hydrogeology, water penetrating radar) used to understand the location of a drowned person

NASA Astrophysics Data System (ADS)

Ruffell, Alastair

2014-05-01

An unusual application of hydrological understanding to a police search is described. The lacustrine search for a missing person provided reports of bottom-water currents in the lake and contradictory indications from cadaver dogs. A hydrological model of the area was developed using pre-existing information from side scan sonar, a desktop hydrogeological study and deployment of water penetrating radar (WPR). These provided a hydrological theory for the initial search involving subaqueous groundwater flow, focused on an area of bedrock surrounded by sediment, on the lake floor. The work shows the value a hydrological explanation has to a police search operation (equally to search and rescue). With hindsight, the desktop study should have preceded the search, allowing better understanding of water conditions. The ultimate reason for lacustrine flow in this location is still not proven, but the hydrological model explained the problems encountered in the initial search.

Tephras in lacustrine sediments of the Sarliève marsh (French Massif Central): age and preservation

NASA Astrophysics Data System (ADS)

Fourmont, Agathe; Macaire, Jean-Jacques; Bréhéret, Jean-Gabriel; Argant, Jacqueline; Prat, Béatrice; Vernet, Gérard

2006-12-01

The Sarliève marsh sediments (Massif Central, France) contain two tephras. The first tephra [ 13.7±0.4ka(2δ), ca. 12 000 BP], regionally well known, enables to date the beginning of lacustrine infill to the Lateglacial. The second tephra, the 'tephra de Sarliève', the emitting volcano of which is unknown, would be dated to around the Early Subboreal from pollen data. This occurrence, after the discovery of the 'tephra de Beaunit', emphasizes that volcanic eruption(s) occurred in the 'Chaîne des Puys' or in the volcanic Cézallier more than 1000 years after the last known eruption (Pavin) in the 'Chaîne des Puys' at around 6.6/6.7 ka (5800/5900 BP). In the Sarliève piles, these tephras, well preserved in thick and more silicated deposits of deltas, were not observed in carbonated basin sediments where they were altered. The abundance of authigenic zeolites formed during the Lateglacial in restricted depocentre lacustrine waters allows us to detect initial CF1 tephra occurrence. To cite this article: A. Fourmont et al., C. R. Geoscience 338 (2006).

Space Station Furnace Facility Core. Requirements definition and conceptual design study. Volume 2: Technical report. Appendix 6: Technical summary reports

NASA Technical Reports Server (NTRS)

1992-01-01

The Space Station Furnace Facility (SSFF) is a modular facility for materials research in the microgravity environment of the Space Station Freedom (SSF). The SSFF is designed for crystal growth and solidification research in the fields of electronic and photonic materials, metals and alloys, and glasses and ceramics and will allow for experimental determination of the role of gravitational forces in the solidification process. The facility will provide a capability for basic scientific research and will evaluate the commercial viability of low-gravity processing of selected technologically important materials. The facility is designed to support a complement of furnace modules as outlined in the Science Capabilities Requirements Document (SCRD). The SSFF is a three rack facility that provides the functions, interfaces, and equipment necessary for the processing of the furnaces and consists of two main parts: the SSFF Core Rack and the two Experiment Racks. The facility is designed to accommodate two experimenter-provided furnace modules housed within the two experiment racks, and is designed to operate these two furnace modules simultaneously. The SCRD specifies a wide range of furnace requirements and serves as the basis for the SSFF conceptual design. SSFF will support automated processing during the man-tended operations and is also designed for crew interface during the permanently manned configuration. The facility is modular in design and facilitates changes as required, so the SSFF is adept to modifications, maintenance, reconfiguration, and technology evolution.

Geochemistry and diagenesis of Miocene lacustrine siliceous sedimentary and pyroclastic rocks, Mytilinii basin, Samos Island, Greece

USGS Publications Warehouse

Stamatakis, M.G.; Hein, J.R.; Magganas, A.C.

1989-01-01

A Late Miocene non-marine stratigraphic sequence composed of limestone, opal-CT-bearing limestone, porcelanite, marlstone, diatomaceous marlstone, dolomite, and tuffite crops out on eastern Samos Island. This lacustrine sequence is subdivided into the Hora Beds and the underlying Pythagorion Formation. The Hora Beds is overlain by the clastic Mytilinii series which contains Turolian (Late Miocene) mammalian fossils. The lacustrine sequence contains volcanic glass and the silica polymorphs opal-A, opal-CT, and quartz. Volcanic glass predominantly occurs in tuffaceous rocks from the lower and upper parts of the lacustrine sequence. Opal-A (diatom frustules) is confined to layers in the upper part of the Hora Beds. Beds rich in opal-CT underlie those containing opal-A. The occurrence of opal-CT is extensive, encompassing the lower Hora Beds and the sedimentary rocks and tuffs of the Pythagorion Formation. A transition zone between the opal-A and opal-CT zones is identified by X-ray diffraction patterns that are intermediate between those of opal-CT and opal-A, perhaps due to a mixture of the two polymorphs. Diagenesis was not advanced enough for opal-CT to transform to quartz or for volcanic glass to transform to opal-C. Based on geochemical and mineralogical data, we suggest that the rate of diagenetic transformation of opal-A to opal-CT was mainly controlled by the chemistry of pore fluids. Pore fluids were characterized by high salinity, moderately high alkalinity, and high magnesium ion activity. These pore fluid characteristics are indicated by the presence of evaporitic salts (halite, sylvite, niter), high boron content in biogenic silica, and by dolomite in both the opal-A and opal-CT-bearing beds. The absence of authigenic K-feldspar, borosilicates, and zeolites also support these pore fluid characteristics. Additional factors that influenced the rate of silica diagenesis were host rock lithology and the relatively high heat flow in the Aegean region from

The relationship between humans and climate across the North Atlantic: what can lacustrine biomarkers tell us?

NASA Astrophysics Data System (ADS)

de Wet, G.; Castañeda, I. S.; Bradley, R. S.; Small, G.; Barrasso, T.

2016-12-01

While climate change has been implicated in the colonization/population dynamics of the North Atlantic region, researchers in many cases are forced to compare archaeological data with distant paleoclimate records, making these linkages tenuous. Our research utilizes novel organic biomarkers in lacustrine sediments to produce paired paleoclimate and human occupancy reconstructions to better address questions surrounding human migration and climate change. Here we present preliminary results from two prominent locations in the history of the European colonization of the North Atlantic. The first, carried out on the Norse "Eastern Settlement" in Southern Greenland, attempts to answer the long-standing question of whether climate change caused the demise of the colony in the 1400s C.E. Second, we use similar techniques to search for evidence of the first peopling of the Faroe Islands, a highly debated topic. The use of lacustrine biomarkers allows for numerous aspects of both paleoclimate and human presence in a catchment to be reconstructed. We reconstruct paleotemperatures using branched glycerol dialkyl glycerol tetraethers (brGDGTs) and alkenones (the UK37 Index), when present. Additionally, will analyze the difference in the hydrogen isotopic composition of long and short-chain plant leaf waxes as a proxy for lake water balance. Human occupancy in the region is investigated using fecal sterols and stanols, primarily created by the breakdown of cholesterol. Some of these compounds, such as coprostanol (the dominant sterol in human waste), provide strong evidence of human settlements and have been identified in some of our lake records. Our preliminary results suggest that temperatures were increasing in SW Greenland during the period when the Norse are thought to have died out, potentially challenging the long-standing view of climate deterioration being the primary cause of their demise. Primary productivity biomarkers from lake Eidisvatnet, in the Faroe Islands

Marine and Lacustrine Organic-rich Sedimentary Unit Time Markers: Implications from Rhenium-Osmium Geochronology

NASA Astrophysics Data System (ADS)

Selby, D.

2011-12-01

Geochronology is fundamental to understand the age, rates and durations of Earth processes. This concerned Arthur Holmes who, for much of his career, attempted to define a geological time scale. This is a topic still important to Earth Scientists today, specifically the chronostratigraphy of sedimentary rocks. Here I explore the Re-Os geochronology of marine and lacustrine sedimentary rocks and its application to yield absolute time constraints for stratigraphy. The past decade has seen the pioneering research of Re-Os organic-rich sedimentary rock geochronology blossom into a tool that can now to be used to accurately and precisely determine depositional ages of organic-rich rock units that have experienced up to low grade greenschist metamorphism. This direct dating of sedimentary rocks is critical where volcanic horizons are absent. As a result, this tool has been applied to timescale calibration, basin correlation, formation duration and the timing of key Earth events (e.g., Neoproterozoic glaciations). The application of Re-Os chronometer to the Devonian-Mississippian boundary contained within the Exshaw Formation, Canada, determined an age of 361.3 ± 2.4 Ma. This age is in accord with U-Pb dates of interbedded tuff horizons and also U-Pb zircon date for the type Devonian-Mississippian Hasselbachtal section, Germany. The agreement of the biostratigraphic and U-Pb constraints of the Exshaw Formation with the Re-Os date illustrated the potential of the Re-Os chronometer to yield age determinations for sedimentary packages, especially in the absence of interbedd tuff horizons and biozones. A Re-Os date for the proposed type section of the Oxfordian-Kimmeridgian boundary, Staffin Bay, Isle of Skye, U.K., gave an age of 154.1 ± 2.2 Ma. This Re-Os age presents a 45 % (1.8 Ma) improvement in precision for the basal Kimmeridgian. It also demonstrated that the duration of the Kimmeridgian is nominally 3.3 Ma and thus is 1.6 Ma shorter than previously indicated. In

Geohydrologic conditions at the nuclear-fuels reprocessing plant and waste-management facilities at the Western New York Nuclear Service Center, Cattaraugus County, New York

USGS Publications Warehouse

Bergeron, M.P.; Kappel, W.M.; Yager, R.M.

1987-01-01

A nuclear-fuel reprocessing plant, a high-level radioactive liquid-waste tank complex, and related waste facilities occupy 100 hectares (ha) within the Western New York Nuclear Service Center near West Valley, N.Y. The facilities are underlain by glacial and postglacial deposits that fill an ancestrial bedrock valley. The main plant facilities are on an elevated plateau referred to as the north plateau. Groundwater on the north plateau moves laterally within a surficial sand and gravel from the main plant building to areas northeast, east, and southeast of the facilities. The sand and gravel ranges from 1 to 10 m thick and has a hydraulic conductivity ranging from 0.1 to 7.9 m/day. Two separate burial grounds, a 4-ha area for low-level radioactive waste disposal and a 2.9-ha area for disposal of higher-level waste are excavated into a clay-rich till that ranges from 22 to 28 m thick. Migration of an organic solvent from the area of higher level waste at shallow depth in the till suggests that a shallow, fractured, oxidized, and weathered till is a significant pathway for lateral movement of groundwater. Below this zone, groundwater moves vertically downward through the till to recharge a lacustrine silt and fine sand. Within the saturated parts of the lacustrine unit, groundwater moves laterally to the northeast toward Buttermilk Creek. Hydraulic conductivity of the till, based on field and laboratory analyses , ranges from 0.000018 to 0.000086 m/day. (USGS)

A facile approach for cupric ion detection in aqueous media using polyethyleneimine/PMMA core-shell fluorescent nanoparticles

NASA Astrophysics Data System (ADS)

Chen, Jian; Zeng, Fang; Wu, Shuizhu; Su, Junhua; Zhao, Jianqing; Tong, Zhen

2009-09-01

A facile approach was developed to produce a dye-doped core-shell nanoparticle chemosensor for detecting Cu2+ in aqueous media. The core-shell nanoparticle sensor was prepared by a one-step emulsifier-free polymerization, followed by the doping of the fluorescent dye Nile red (9-diethylamino- 5H-benzo[alpha] phenoxazine-5-one, NR) into the particles. For the nanoparticles, the hydrophilic polyethyleneimine (PEI) chain segments serve as the shell and the hydrophobic polymethyl methacrylate (PMMA) constitutes the core of the nanoparticles. The non-toxic and biocompatible PEI chain segments on the nanoparticle surface exhibit a high affinity for Cu2+ ions in aqueous media, and the quenching of the NR fluorescence is observed upon binding of Cu2+ ions. This makes the core-shell nanoparticle system a water-dispersible chemosensor for Cu2+ ion detection. The quenching of fluorescence arises through intraparticle energy transfer (FRET) from the dye in the hydrophobic PMMA core to the Cu2+/PEI complexes on the nanoparticle surface. The energy transfer efficiency for PEI/PMMA particles with different diameters was determined, and it is found that the smaller nanoparticle sample exhibits higher quenching efficiency, and the limit for Cu2+ detection is 1 µM for a nanoparticle sample with a diameter of ~30 nm. The response of the fluorescent nanoparticle towards different metal ions was investigated and the nanoparticle chemosensor displays high selectivity and antidisturbance for the Cu2+ ion among the metal ions examined (Na+, K+, Mg2+, Ca2+, Zn2+, Hg2+, Mn2+, Fe2+, Ni2+, Co2+ and Pb2+). This emulsifier-free, biocompatible and sensitive fluorescent nanoparticle sensor may find applications in cupric ion detection in the biological and environmental areas.

A facile approach for cupric ion detection in aqueous media using polyethyleneimine/PMMA core-shell fluorescent nanoparticles.

PubMed

Chen, Jian; Zeng, Fang; Wu, Shuizhu; Su, Junhua; Zhao, Jianqing; Tong, Zhen

2009-09-09

A facile approach was developed to produce a dye-doped core-shell nanoparticle chemosensor for detecting Cu(2+) in aqueous media. The core-shell nanoparticle sensor was prepared by a one-step emulsifier-free polymerization, followed by the doping of the fluorescent dye Nile red (9-diethylamino- 5H-benzo[alpha] phenoxazine-5-one, NR) into the particles. For the nanoparticles, the hydrophilic polyethyleneimine (PEI) chain segments serve as the shell and the hydrophobic polymethyl methacrylate (PMMA) constitutes the core of the nanoparticles. The non-toxic and biocompatible PEI chain segments on the nanoparticle surface exhibit a high affinity for Cu(2+) ions in aqueous media, and the quenching of the NR fluorescence is observed upon binding of Cu(2+) ions. This makes the core-shell nanoparticle system a water-dispersible chemosensor for Cu(2+) ion detection. The quenching of fluorescence arises through intraparticle energy transfer (FRET) from the dye in the hydrophobic PMMA core to the Cu(2+)/PEI complexes on the nanoparticle surface. The energy transfer efficiency for PEI/PMMA particles with different diameters was determined, and it is found that the smaller nanoparticle sample exhibits higher quenching efficiency, and the limit for Cu(2+) detection is 1 microM for a nanoparticle sample with a diameter of approximately 30 nm. The response of the fluorescent nanoparticle towards different metal ions was investigated and the nanoparticle chemosensor displays high selectivity and antidisturbance for the Cu(2+) ion among the metal ions examined (Na(+), K(+), Mg(2+), Ca(2+), Zn(2+), Hg(2+), Mn(2+), Fe(2+), Ni(2+), Co(2+) and Pb(2+)). This emulsifier-free, biocompatible and sensitive fluorescent nanoparticle sensor may find applications in cupric ion detection in the biological and environmental areas.

Facile fabrication of core cross-linked micelles by RAFT polymerization and enzyme-mediated reaction.

PubMed

Wu, Yukun; Lai, Quanyong; Lai, Shuqi; Wu, Jing; Wang, Wei; Yuan, Zhi

2014-06-01

Polymeric micelles formed in aqueous solution by assembly of amphiphilic block copolymers have been extensively investigated due to their great potential as drug carriers. However, the stability of polymeric assembly is still one of the major challenges in delivering drugs to tissues and cells. Here, we report a facile route to fabricate core cross-linked (CCL) micelles using an enzymatic polymerization as the cross-linking method. We present synthesis of poly(ethylene glycol)-block-poly(N-isopropyl acrylamide-co-N-(4-hydroxyphenethyl) acrylamide) diblock copolymer PEG-b-P(NIPAAm-co-NHPAAm) via reversible addition-fragmentation chain transfer (RAFT) polymerization. The diblock copolymer was then self-assembled into non-cross-linked (NCL) micelles upon heating above the lower critical solution temperature (LCST), and subsequently cross-linked using horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) as enzyme and oxidant. The characterization of the diblock copolymer and micelles were studied by NMR, DLS, UV-vis, and fluorescence spectroscopy. The fluorescence study reveals that the cross-linking process endows the micelles with much lower critical micelle concentration (CMC). In addition, the drug release study shows that the CCL micelles have lower release amount of doxorubicin (DOX) than the NCL micelles due to the enhanced stability of the CCL micelles by core cross-linking process. Copyright © 2014 Elsevier B.V. All rights reserved.

High-resolution multi-proxy reconstruction of Lake Ighiel (Western Carpathians, Romania): processes and controlling factors of lacustrine dynamics during the mid and late Holocene

NASA Astrophysics Data System (ADS)

Haliuc, Aritina; Veres, Daniel; Hubay, Katalin; Begy, Robert; Brauer, Achim; Hutchinson, Simon; Braun, Mihaly

2016-04-01

Concerns about current and prospective environmental change have increased the interest in past climate variability and its impact on the bio-hydro-atmosphere and human society. Acting as high-resolution terrestrial archives, lacustrine sediments are the result of the complex interaction between internal and external forcing and an important tool in efforts to resolve questions related to the palaeoclimatic and palaeoenvironmental conditions of the recent past. Here we discuss a new, high-resolution sedimentary record from the Romanian Carpathians (central-eastern Europe). Lake Ighiel (46° 10'50"N, 23° 22'00"E) is a small lake located in a mid-altitude mountain belt (Trascau Mountains) at an altitude of 924 m ( lake maximum depth 9 m; catchment area 487 ha). We employ detailed 210Pb and 14C dating coupled with high-resolution X-ray fluorescence scanning (μ-XRF) measurements, long-core sedimentary logging, environmental magnetic proxies (susceptibility, natural and induced remanences) in an attempt to trace the 6000 years evolution of lake-catchment system. More specifically, we discuss: i) the temporal evolution of the main sedimentation phases of the lake based on sedimentological, geochemical and magnetic proxies; ii) the amplitude and interplay of processes (natural and/or anthropogenic) controlling the depositional environment through time; iii) assess the contribution of each controlling factors and reconstruct the evolution of lacustrine system and palaeoclimate forcing using multivariate statistics. The sedimentary record can be divided into six phases based on alternating high and low detrital fluxes, oscillating lacustrine productivity and redox conditions. A series of detrital events (5200; 4800; 5400; 5250; 4500; 4050; 3800; 3500; 3250; 3050; 2650; 2350; 2250; 1400; 1100; 500; 100 cal yr BP) were identified by microfacies analyses and X-ray fluorescence scanning (μ-XRF) analysis. These events are reflected in most of the parameters and appear

Sedimentology and geochemistry of lacustrine sequences of the upper Pleistocene and holocene in intertropical area (Lake Magadi and Green crater lake): paleoclimatic implications

NASA Astrophysics Data System (ADS)

Damnati, B.

1993-05-01

Sedimentological and geochemical analyses have been carried out on lacustrine deposits of East Africa, at Lake Magadi (2°S, 36°E, Kenya) and at Green Crater Lake (0°S, 36°E, Kenya), to determine the parameters controlling climatic and environmental dynamics during late Pleistocene and Holocene. These sedimentary sequences were collected with a stationary piston corer. At Lake Magadi (Fig. 1), sedimentary and geochemical control show three phases of lake level variation which corresponds to climatic change occurring during the last 40 thousand years. These phases were defined by three lithostratigraphic units. Laminated deposits of Lake Magadi were formed during a wet period. Analysis of these laminae define two microfacies: a dark lamina, characterised by lacustrine organic matter and a light lamina enriched in detritus, carbonates (CaCO 3) and magadiite (NaSi 7O 13(OH) 3, 3H 2O). The formation and preservation of each couplet was favoured by climatic contrast, lake stratification and various origin of the sediments (autochthon and allochthon) in the drainage basin. Therefore a relative chronology can be derived from laminae counting and the duration of deposition of each couplet. Spectral analysis applied on variation of the laminae thickness, shows the existence of three main periods, 4-7 years, 8-14 years and 18-30 years, respectively (Fig. 2). These cyclicites of the lacustrine environment precise former determinations established on more recent lacustrine sequences from East Africa. They are related to the global climatic cycle (quasi-biannual oscillations, El Nino Southern Oscillations and the sun spot cycles). At Green Crater Lake, the study of the sedimentary sequence was completed by physico-chemical analysis of the waters and interface sediments which demonstrate the carbonate, sodium, bicarbonate composition and the thermal and chemical stratification of the modern lake. The sedimentary sequence is characterized by volcanic deposits overlain by

Mihi Breccia: A stack of lacustrine sediments and subaqueous pyroclastic flows within the Taupo Volcanic Zone, New Zealand

USGS Publications Warehouse

Downs, Drew

2016-01-01

The Taupo Volcanic Zone (TVZ), New Zealand, encompasses a wide variety of arc-related strata, although most of its small-volume (non-caldera-forming) eruptions are poorly-exposed and extensively hydrothermally altered. The Mihi Breccia is a stratigraphic sequence consisting of interbedded rhyolitic pyroclastic flows and lacustrine sediments with eruption ages of 281 ± 18 to at least 239 ± 6 ka (uncertainties at 2σ). In contrast to other small-volume rhyolitic eruptions within the TVZ, Mihi Breccia is relatively well-exposed within the Paeroa fault block, and contains minimal hydrothermal alteration. Pyroclastic flow characteristics and textures including: 1) breadcrusted juvenile clasts, 2) lack of welding, 3) abundant ash-rich matrix, 4) lack of fiamme and eutaxitic textures, 5) lack of thermal oxidation colors, 6) lack of cooling joints, 7) exclusive lacustrine sediment lithic clasts, and 8) interbedding with lacustrine sediments, all indicating that Mihi Breccia strata originated in a paleo-lake system. This ephemeral paleo-lake system is inferred to have lasted for > 50 kyr (based on Mihi Breccia age constraints), and referred to as Huka Lake. Mihi Breccia pyroclastic flow juvenile clast geochemistry and petrography correspond with similar-aged (264 ± 8, 263 ± 10, and 247 ± 4 ka) intra-caldera rhyolite domes filling the Reporoa caldera (source of the 281 ± 81 Kaingaroa Formation ignimbrite). These exposed intra-caldera rhyolite domes (as well as geophysically inferred subsurface domes) are proposed to be source vents for the Mihi Breccia pyroclastic flows. Soft-sediment deformation associated with Mihi Breccia strata indicate either seismic shock, rapid sediment loading during pyroclastic flow emplacement, or both. Thus, the Mihi Breccia reflects a prolonged series of subaqueous rhyolite dome building and associated pyroclastic flows, accompanied by seismic activity, emplaced into a large paleo-lake system within the TVZ.

Mihi Breccia: A stack of lacustrine sediments and subaqueous pyroclastic flows within the Taupo Volcanic Zone, New Zealand

NASA Astrophysics Data System (ADS)

Downs, Drew T.

2016-11-01

The Taupo Volcanic Zone (TVZ), New Zealand, encompasses a wide variety of arc-related strata, although most of its small-volume (non-caldera-forming) eruptions are poorly-exposed and extensively hydrothermally altered. The Mihi Breccia is a stratigraphic sequence consisting of interbedded rhyolitic pyroclastic flows and lacustrine sediments with eruption ages of 281 ± 18 to at least 239 ± 6 ka (uncertainties at 2σ). In contrast to other small-volume rhyolitic eruptions within the TVZ, Mihi Breccia is relatively well-exposed within the Paeroa fault block, and contains minimal hydrothermal alteration. Pyroclastic flow characteristics and textures include: 1) prismatically jointed juvenile clasts, 2) lack of welding, 3) abundant ash-rich matrix, 4) lack of fiamme and eutaxitic textures, 5) lack of thermal oxidation colors, 6) lack of cooling joints, 7) exclusive lacustrine sediment lithic clasts, and 8) interbedding with lacustrine sediments, all indicating that Mihi Breccia strata originated in a paleo-lake system. This ephemeral paleo-lake system is inferred to have lasted for > 50 kyr (based on Mihi Breccia age constraints), and referred to as Huka Lake. Mihi Breccia pyroclastic flow juvenile clast geochemistry and petrography correspond with similar-aged (264 ± 8, 263 ± 10, and 247 ± 4 ka) intra-caldera rhyolite domes filling the Reporoa caldera (source of the 281 ka Kaingaroa Formation ignimbrite). These exposed intra-caldera rhyolite domes (as well as geophysically inferred subsurface domes) are proposed to be source vents for the Mihi Breccia pyroclastic flows. Soft-sediment deformation associated with Mihi Breccia strata indicates either seismic shock, rapid sediment loading during pyroclastic flow emplacement, or both. Thus, the Mihi Breccia reflects a prolonged series of subaqueous rhyolite dome building and associated pyroclastic flows, accompanied by seismic activity, emplaced into a large paleo-lake system within the TVZ.

Storm and tide influenced depositional architecture of the Pliocene-Pleistocene Chad Formation, Chad Basin (Bornu Sub-basin) NE Nigeria: A mixed fluvial, deltaic, shoreface and lacustrine complex

NASA Astrophysics Data System (ADS)

Shettima, Bukar; Kyari, Aji Maina; Aji, Mallam Musa; Adams, Fatimoh Dupe

2018-07-01

Lithofacies analyses of the upper part of the Chad Formation (Bama Ridge Complex) in the Bornu Sub-basin of the Chad Basin indicated four facies associations; fluvial, deltaic, shoreface and lacustrine sequences. The fluvial sequences are composed of fining upward cycles with successive occurrence of planar crossbedded sandstone facies displaying unimodal paleocurrent system and rare mudstone facies typical of braided river system. The deltaic succession consists of both fining and coarsening upwards cycles with the former depicting fluvial setting of an upper delta plain while the later suggestive of mouth-bar sequences. The setting displays a polymodal current system of fluvial, waves, storms and tides that were primarily induced by complex interactions of seiches and lunar tides. Similar current systems devoid of fluvial patterns were reflected in the coarsening upward packages of the shoreface sequences. Lacustrine succession composed of thick bioturbated mudstone facies generally defines the base of these coarsening upward profiles, giving a fluvio-lacustrine geomorphic relief where complex interaction developed the deltaic and shoreface facies along its shorelines. Clay mineral fractions of the formation are dominantly kaolinitic, indicating a predominantly humid tropical-subtropical climatic condition during their deposition. This climatic regime falls within the African humid period of the early-mid Holocene that led to the third lacustrine transgression of the Lake Mega-Chad, whereas the subordinate smectite mineralization points to aridification that characterizes most of the post humid period to recent.

Facile one-step synthesis of Ag@Fe3O4 core-shell nanospheres for reproducible SERS substrates

NASA Astrophysics Data System (ADS)

Sun, Lijuan; He, Jiang; An, Songsong; Zhang, Junwei; Ren, Dong

2013-08-01

A facile approach has been developed to synthesize Ag@Fe3O4 core-shell nanospheres, in which the Ag nanoparticle core was well wrapped by a permeable Fe3O4 shell. An in situ reduction of AgNO3 and Fe(NO3)3 was the basis of this one-step method with ethylene glycol as the reducing agent. The as-obtained Ag@Fe3O4 nanospheres were a highly efficient surface-enhanced Raman scattering (SERS) substrate; high reproducibility, stability, and reusability were obtained by employing 4-aminothiophenol (4-ATP) and rhodamine 6G (R6G) as the Raman probe molecules. It was revealed that the SERS signals of 4-ATP and R6G on the Ag@Fe3O4 nanospheres were much stronger than those on the pure Ag nanoparticles, demonstrating that the magnetic enrichment procedures can improve SERS detection sensitivity efficiently. A highly efficient and recyclable SERS substrate was produced by the new model system that has potential applications in chemical and biomolecular assays.

Consensus-based approach to develop a measurement framework and identify a core set of indicators to track implementation and progress towards effective coverage of facility-based Kangaroo Mother Care.

PubMed

Guenther, Tanya; Moxon, Sarah; Valsangkar, Bina; Wetzel, Greta; Ruiz, Juan; Kerber, Kate; Blencowe, Hannah; Dube, Queen; Vani, Shashi N; Vivio, Donna; Magge, Hema; De Leon-Mendoza, Socorro; Patterson, Janna; Mazia, Goldy

2017-12-01

As efforts to scale up the delivery of Kangaroo Mother Care (KMC) in facilities are increasing, a standardized approach to measure implementation and progress towards effective coverage is needed. Here, we describe a consensus-based approach to develop a measurement framework and identify a core set of indicators for monitoring facility-based KMC that would be feasible to measure within existing systems. The KMC measurement framework and core list of indicators were developed through: 1) scoping exercise to identify potential indicators through literature review and requests from researchers and program implementers; and 2) face-to-face consultations with KMC and measurement experts working at country and global levels to review candidate indicators and finalize selection and definitions. The KMC measurement framework includes two main components: 1) service readiness, based on the WHO building blocks framework; and 2) service delivery action sequence covering identification, service initiation, continuation to discharge, and follow-up to graduation. Consensus was reached on 10 core indicators for KMC, which were organized according to the measurement framework. We identified 4 service readiness indicators, capturing national level policy for KMC, availability of KMC indicators in HMIS, costed operational plans for KMC and availability of KMC services at health facilities with inpatient maternity services. Six indicators were defined for service delivery, including weighing of babies at birth, identification of those ≤2000 g, initiation of facility-based KMC, monitoring the quality of KMC, status of babies at discharge from the facility and levels of follow-up (according to country-specific protocol). These core KMC indicators, identified with input from a wide range of global and country-level KMC and measurement experts, can aid efforts to strengthen monitoring systems and facilitate global tracking of KMC implementation. As data collection systems advance, we

Facile consecutive solvothermal growth of highly fluorescent InP/ZnS core/shell quantum dots using a safer phosphorus source.

PubMed

Byun, Ho-June; Song, Woo-Seuk; Yang, Heesun

2011-06-10

The work presents a facile, stepwise synthetic approach for the production of highly fluorescent InP/ZnS core/shell quantum dots (QDs) by using a safer phosphorus (P) precursor. First, InP quantum dots (QDs) were solvothermally prepared at 180 °C for 24 h by using a P source of P(N(CH(3))(2))(3). The as-grown InP QDs were consecutively placed in another solvothermal condition for ZnS shell overcoating. In contrast to the almost non-fluorescent InP QDs, due to their highly defective surface states, the ZnS-coated InP QDs were highly fluorescent as a result of effective surface passivation. After the shell growth, the resulting InP/ZnS core/shell QDs were subjected to a size-sorting processing, by which red- to green-emitting QDs with quantum yields (QYs) of 24-60% were produced. Solvothermal shell growth parameters such as the reaction time and Zn/In solution concentration ratio were varied and optimized toward the highest QYs of core/shell QDs.

Facile consecutive solvothermal growth of highly fluorescent InP/ZnS core/shell quantum dots using a safer phosphorus source

NASA Astrophysics Data System (ADS)

Byun, Ho-June; Song, Woo-Seuk; Yang, Heesun

2011-06-01

The work presents a facile, stepwise synthetic approach for the production of highly fluorescent InP/ZnS core/shell quantum dots (QDs) by using a safer phosphorus (P) precursor. First, InP quantum dots (QDs) were solvothermally prepared at 180 °C for 24 h by using a P source of P(N(CH3)2)3. The as-grown InP QDs were consecutively placed in another solvothermal condition for ZnS shell overcoating. In contrast to the almost non-fluorescent InP QDs, due to their highly defective surface states, the ZnS-coated InP QDs were highly fluorescent as a result of effective surface passivation. After the shell growth, the resulting InP/ZnS core/shell QDs were subjected to a size-sorting processing, by which red- to green-emitting QDs with quantum yields (QYs) of 24-60% were produced. Solvothermal shell growth parameters such as the reaction time and Zn/In solution concentration ratio were varied and optimized toward the highest QYs of core/shell QDs.

Core Facility of the Juelich Observatory for Cloud Evolution (JOYCE - CF)

NASA Astrophysics Data System (ADS)

Beer, J.; Troemel, S.

2017-12-01

A multiple and holistic multi-sensor monitoring of clouds and precipitation processes is a challenging but promising task in the meteorological community. Instrument synergies offer detailed views in microphysical and dynamical developments of clouds. Since 2017 The the Juelich Observatory for Cloud Evolution (JOYCE) is transformed into a Core Facility (JOYCE - CF). JOYCE - CF offers multiple long-term remote sensing observations of the atmosphere, develops an easy access to all observations and invites scientists word wide to exploit the existing data base for their research but also to complement JOYCE-CF with additional long-term or campaign instrumentation. The major instrumentation contains a twin set of two polarimetric X-band radars, a microwave profiler, two cloud radars, an infrared spectrometer, a Doppler lidar and two ceilometers. JOYCE - CF offers easy and open access to database and high quality calibrated observations of all instruments. E.g. the two polarimetric X-band radars which are located in 50 km distance are calibrated using the self-consistency method, frequently repeated vertical pointing measurements as well as instrument synergy with co-located micro-rain radar and distrometer measurements. The presentation gives insights into calibration procedures, the standardized operation procedures and recent synergistic research exploiting our radars operating at three different frequencies.

Late Holocene Lacustrine Records of Climate and Vegetation Change From Southernmost South America

NASA Astrophysics Data System (ADS)

Moy, C. M.; Dunbar, R. B.; Francois, J.; Moreno, P. I.; Villa Martínez, R.

2006-12-01

The westerly wind field is one of the most prominent atmospheric circulation features in the Southern Hemisphere and has a major impact on the climate of southern South America as well as Southern Ocean hydrography. Southernmost South America is well-located to investigate past changes in the westerly winds because regional precipitation variability is controlled by the location and intensity of the wind field and it is the only landmass to extend within the core of the westerlies. Here we present late Holocene lacustrine records of climate change related to the westerlies from southern Patagonia, Chile. We focus on Lago Guanaco, a small hydrologically closed-basin lake in Southern Patagonia, and use stable isotope and pollen data from this site and three additional lakes in order to reconstruct changes in moisture balance related to the westerlies. Lago Guanaco (51°S, 72°W) is located close to the Nothofagus forest-Patagonian Steppe transition in the eastern region of Parque Nacional Torres del Paine. The location and composition of this important biological discontinuity is highly sensitive to the W-E precipitation gradient throughout Patagonia. The 4.75 m sediment core we obtained from the center of the lake has high concentrations of organic mater in addition to ostracodes and bivalves, which are relatively rare in Chilean Patagonia. Eleven AMS radiocarbon dates on organic and carbonate fractions indicate that the record spans the last ~14,400 cal yr BP and modern dates from core tops suggest little influence by old carbon sources. Changes in moisture balance and forest density/proximity are reflected in downcore variations in δ18Obivalve and δ18Oostracode, the Nothofagus/Poaceae paleovegetation index, and the C/N ratio of bulk decalcified organic matter. Combined, these variables document changes in the isotopic composition of the lake water, which largely reflect the isotopic composition of precipitation and the influence of evaporation, as well as shifts

Lacustrine Records of Holocene Mountain Glacier Fluctuations from Western Greenland

NASA Astrophysics Data System (ADS)

Schweinsberg, A.; Briner, J. P.; Bennike, O.

2014-12-01

Recent studies have focused on documenting fluctuations of the Greenland Ice Sheet margin throughout the Holocene but few data exist that constrain past changes of local glaciers independent of the ice sheet. Our research combines proglacial lake sediment analysis with cosmogenic 10Be dating of Holocene moraines and radiocarbon dating of ice-cap-killed vegetation with an overall objective to use this multi-proxy approach to generate a detailed record of the coupled climate-glacier system through the Holocene. Here, we present lacustrine records of mountain glacier variability from continuous pro-glacial lake sediment sequences recovered from two glaciated catchments in northeastern Nuussuaq, western Greenland. We use radiocarbon-dated sediments from Sikuiui and Pauiaivik lakes to reconstruct the timing of advance and retreat of local glaciers. Sediments were characterized with magnetic susceptibility (MS), gamma density, Itrax XRF and visible reflectance spectroscopy at 0.2 cm intervals and sediment organic matter at 0.5 cm intervals. Basal radiocarbon ages provide minimum-age constraints on deglaciation from Sikuiui and Pauiaivik lakes of ~9.6 and 8.7 ka, respectively. Organic-rich gyttja from deglaciation until ~5.0 ka in Pauiaivik Lake suggests minimal glacial extent there while slightly elevated MS values from ~9.0 - 7.0 ka in Sikuiui Lake may reflect early Holocene glacial advances. Minerogenic sediment input gradually increases starting at ~5.0 ka in Pauiaivik Lake, which we interpret as the onset of Neoglaciation in the catchment. Furthermore, a distinct episode of enhanced glacial activity from ~4.0 - 2.2 ka in Sikuiui Lake may be correlative to a period of persistent snowline lowering evidenced by radiocarbon dates of ice-killed vegetation from nearby ice cap margins. Results from these lacustrine records and our ice-killed vegetation dataset suggest a middle Holocene onset of Neoglaciation ~5.0 - 4.0 ka in this region. We are supplementing these records

Experiment/facility requirements document for the Space Station Furnace Facility. Section 1: Integrated configuration

NASA Astrophysics Data System (ADS)

1992-05-01

The function of the Space Station Furnace Facility (SSFF) is to support materials research into the crystal growth and solidification processes of electronic and photonic materials, metals and alloys, and glasses and ceramics. To support this broad base of research requirements, the SSFF will employ a variety of furnace modules which will be operated, regulated, and supported by a core of common subsystems. Furnace modules may be reconfigured or specifically developed to provide unique solidification conditions for each set of experiments. The SSFF modular approach permits the addition of new or scaled-up furnace modules to support the evolution of the facility as new science requirements are identified. The SSFF Core is of modular design to permit augmentation for enhanced capabilities. The fully integrated configuration of the SSFF will consist of three racks with the capability of supporting up to two furnace modules per rack. The initial configuration of the SSFF will consist of two of the three racks and one furnace module. This Experiment/Facility Requirements Document (E/FRD) describes the integrated facility requirements for the Space Station Freedom (SSF) Integrated Configuration-1 (IC1) mission. The IC1 SSFF will consist of two racks: the Core Rack, with the centralized subsystem equipment; and the Experiment Rack-1, with Furnace Module-1 and the distributed subsystem equipment to support the furnace. The SSFF support functions are provided by the following Core subsystems: power conditioning and distribution subsystem (SSFF PCDS); data management subsystem (SSFF DMS); thermal control Subsystem (SSFF TCS); gas distribution subsystem (SSFF GDS); and mechanical structures subsystem (SSFF MSS).

Experiment/facility requirements document for the Space Station Furnace Facility. Section 1: Integrated configuration

NASA Technical Reports Server (NTRS)

1992-01-01

The function of the Space Station Furnace Facility (SSFF) is to support materials research into the crystal growth and solidification processes of electronic and photonic materials, metals and alloys, and glasses and ceramics. To support this broad base of research requirements, the SSFF will employ a variety of furnace modules which will be operated, regulated, and supported by a core of common subsystems. Furnace modules may be reconfigured or specifically developed to provide unique solidification conditions for each set of experiments. The SSFF modular approach permits the addition of new or scaled-up furnace modules to support the evolution of the facility as new science requirements are identified. The SSFF Core is of modular design to permit augmentation for enhanced capabilities. The fully integrated configuration of the SSFF will consist of three racks with the capability of supporting up to two furnace modules per rack. The initial configuration of the SSFF will consist of two of the three racks and one furnace module. This Experiment/Facility Requirements Document (E/FRD) describes the integrated facility requirements for the Space Station Freedom (SSF) Integrated Configuration-1 (IC1) mission. The IC1 SSFF will consist of two racks: the Core Rack, with the centralized subsystem equipment; and the Experiment Rack-1, with Furnace Module-1 and the distributed subsystem equipment to support the furnace. The SSFF support functions are provided by the following Core subsystems: power conditioning and distribution subsystem (SSFF PCDS); data management subsystem (SSFF DMS); thermal control Subsystem (SSFF TCS); gas distribution subsystem (SSFF GDS); and mechanical structures subsystem (SSFF MSS).

Past Holocene detritism quantification and modeling from lacustrine archives in order to deconvoluate human-climate interactions on natural ecosystem over long time-scale

NASA Astrophysics Data System (ADS)

Simonneau, Anaëlle; Chapron, Emmanuel; Di Giovanni, Christian; Galop, Didier; Darboux, Frédéric

2014-05-01

Water budget is one of the main challenges to paleoclimate researchers in relation to present-day global warming and its consequences for human societies. Associated soil degradation and erosion are thereby becoming a major concern in many parts of the world and more particularly in the Alps. Moreover, humans are considered as geomorphologic agents since few thousand years and it is now recognized that such an impact on natural ecosystem profoundly modified soils properties as well as aquatic ecosystems dynamics over long-term periods. The quantification of such inference over long time-scale is therefore essential to establish new policies to reduce mechanic soil erosion, which is one of the dominant processes in Europe, and anticipate the potential consequences of future climate change on hydric erosion. The mechanical erosion of continental surfaces results from climatic forcing, but can be amplified by the anthropogenic one. We therefore suggest that quantifying and modelling soil erosion processes within comparable Holocene lacustrine archives, allows to estimate and date which and when past human activities have had an impact on soil fluxes over the last 10000 years. Based on the present-day geomorphology of the surrounding watershed and the evolution of the vegetation cover during the Holocene, we develop an interdisciplinary approach combining quantitative organic petrography (i.e. optical characterization and quantification of soil particles within lake sediments) with high-resolution seismic profiling, age-depth models on lacustrine sediment cores and soil erosional susceptibility modeling, in order to estimate the annual volume of soil eroded over the last 10000 years, and in fine to quantify the volume of human-induced soil erosion during the Holocene period. This method is applied to close but contrasted mountainous lacustrine environments from the western French Alps: lakes Blanc Huez and Paladru, sensitive to same climatic influences but where past

Marine-to-lacustrine transition, mud volcanism, and slope instability in an active tectonic setting: the MIS 5 to 4 transition in the Sea of Marmara, Turkey

NASA Astrophysics Data System (ADS)

Grall, Céline; Henry, Pierre; Kendé, Julia; Namık Çaǧatay, M.; Kadir Eriş, K.; Paillès, Christine; Sorlien, Christopher; Shillington, Donna; McHugh, Cecilia; Steckler, Michael; Çifçi, Günay; Géli, Louis

2016-04-01

In the Sea of Marmara, glacio-eustatic cycles set the tempo of a complex history of disconnection and reconnection with the Black Sea and with the global ocean through the Mediterranean Sea. As a result, the sedimentary record consists of alternating high stand marine sediments and lowstand sea or lake sediments. The Sea of Marmara is also an active transtensional basin along the Northern branch of the North Anatolian Fault (NNAF), which accommodates most (~3/4) of the 21-27 mm/a dextral slip between Eurasia and Anatolia. This peculiar setting makes the Sea of Marmara an exceptional site to study the interplay of paleo-environmental factors and seismotectonic processes. Notably, Mass Transport Deposits (MTDs) crossing the faults provide offset markers although their age remains uncertain. A high resolution seismic stratigraphic model has been proposed for 100 ka glacial cycles, based on onlap sequences within basins, and paleo-deltas at shorelines. The sedimentation rate in basins decreases during episodes of sea-level rise and reach maximum values during low stands. Remarkably, seismic reflector sequences display nearly identical character for locations with similar sedimentation rate. The uppermost sequence boundary reflector (Red-H1) has been recently cored at several locations during MARSITECRUISE (Ifremer R/V Pourquoi Pas?, Oct-Nov. 2014), enabled us to correlate high resolution seismic data with core data. The Red-H1 reflector is regionally characterized by a high amplitude and a reverse polarity. Correlations between seismic data and piston core logs indicate that the reverse polarity of this reflector may be explained by a negative density contrast between lacustrine sediments above and a greenish sapropellic layer of several meters thickness below. On shelves, Red-H1 is on top of the low stand wedge. On slopes and topographic highs, Red-H1 appears as an erosional surface laterally correlative with an onlapping unit in basins and is frequently overlain by

Geochemical characteristics of organic compounds in a permafrost sediment core sample from northeast Siberia, Russia

NASA Technical Reports Server (NTRS)

Matsumoto, G. I.; Friedmann, E. I.; Gilichinsky, D. A.

1995-01-01

We studied total organic carbon (TOC), hydrocarbons and fatty acids in a permafrost sediment core sample (well 6-90, length 32.0 m, 1.5-2.5 Ma BP) from northeast Siberia (approximately 70 degrees N, 158 degrees E), Russia, to elucidate their geochemical features in relation to source organisms and paleoenvironmental conditions. Long-chain n-alkanes and n-alkanoic acids (>C19) were most predominant hydrocarbons and fatty acids, respectively, so organic matter in the sediment core was derived mainly from vascular plants and, to a much smaller extent, from bacteria. Low concentrations of unsaturated fatty acids revealed that organic matter in the sediment core was considerably degraded during and/or after sedimentation. The predominance of vascular plant components, the major ionic components of nonmarine sources, and geological data strongly implied that the sediment layers were formed in shallow lacustrine environments, such as swamp with large influences of tundra or forest-tundra vegetation. Also, no drastic changes in paleoenvironmental conditions for biological activity or geological events, such as sea transgressions or ice-sheet influences, occurred at the sampling site approximately 100 km from the coast of the East Siberian Sea during the late Pliocene an early Pleistocene periods.

Lithostratigraphy and physical properties of lacustrine sediments of the last ca. 150 kyr from Chalco basin, central México

NASA Astrophysics Data System (ADS)

Ortega-Guerrero, Beatriz; Lozano-García, Socorro; Herrera-Hernández, Dimitris; Caballero, Margarita; Beramendi-Orosco, Laura; Bernal, Juan Pablo; Torres-Rodríguez, Esperanza; Avendaño-Villeda, Diana

2017-11-01

The recognition of past climatic fluctuations in sedimentary sequences in central Mexico is relevant for understanding the forcing mechanisms and responses of climatic system in the northern American tropic. Moreover, in this active volcanic setting the sedimentary record preserves the history of past volcanic activity. Climatic and environmental variability has been documented for the last tenths of thousands of years from the upper lacustrine sediments in Chalco basin. A series of cores drilled down to 122 m depth in this basin offer a long, continuous and high resolution record of past climatic changes of the last ca. 150 kyr in this region. Here we present the detailed lithostratigraphy and some physical properties (magnetic susceptibility and density) of the master sequence. Sedimentary components and their abundance were identified and quantified in smear slides and direct core observations. Age model is based on 13 14C and one 230Th/U dates. Based on their facies association seven lithostratigraphic units were defined, which reflect the main stages of lake Chalco evolution. These phases closely match the marine isotopic stages. The data reveal that at the end of MIS6 Chalco was a relatively deep and stratified freshwater lake. During MIS5 the depositional environment fluctuated between low lake stands to marshy and marginal playa settings with sporadic flooding events, and severe arid periods resulted in aerial exposure of lake sediments. Low lake stands persisted during MIS4 and MIS3, with minor fluctuations towards slightly deeper phases. The Last Glacial Maximum (LGM) and the deglacial period (21-13 kyr) are characterized by intense volcanism. The early and mid-Holocene high calcareous content and alkaline-subsaline lake suggest dry conditions. The fluctuations of lake levels inferred provide the basis for future paleoclimatic works.

Morphology and Fractal Characterization of Multiscale Pore Structures for Organic-Rich Lacustrine Shale Reservoirs

NASA Astrophysics Data System (ADS)

Wang, Yang; Wu, Caifang; Zhu, Yanming; Chen, Shangbin; Liu, Shimin; Zhang, Rui

Lacustrine shale gas has received considerable attention and has been playing an important role in unconventional natural gas production in China. In this study, multiple techniques, including total organic carbon (TOC) analysis, X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM), helium pycnometry and low-pressure N2 adsorption have been applied to characterize the pore structure of lacustrine shale of Upper Triassic Yanchang Formation from the Ordos Basin. The results show that organic matter (OM) pores are the most important type dominating the pore system, while interparticle (interP) pores, intraparticle (intraP) and microfractures are also usually observed between or within different minerals. The shapes of OM pores are less complex compared with the other two pore types based on the Image-Pro Plus software analysis. In addition, the specific surface area ranges from 2.76m2/g to 10.26m2/g and the pore volume varies between 0.52m3/100g and 1.31m3/100g. Two fractal dimensions D1 and D2 were calculated using Frenkel-Halsey-Hill (FHH) method, with D1 varying between 2.510 and 2.632, and D2 varying between 2.617 and 2.814. Further investigation indicates that the fractal dimensions exhibit positive correlations with TOC contents, whereas there is no definite relationship observed between fractal dimensions and clay minerals. Meanwhile, the fractal dimensions increase with the increase in specific surface area, and is negatively correlated with the pore size.

SedCT: MATLAB™ tools for standardized and quantitative processing of sediment core computed tomography (CT) data collected using a medical CT scanner

NASA Astrophysics Data System (ADS)

Reilly, B. T.; Stoner, J. S.; Wiest, J.

2017-08-01

Computed tomography (CT) of sediment cores allows for high-resolution images, three-dimensional volumes, and down core profiles. These quantitative data are generated through the attenuation of X-rays, which are sensitive to sediment density and atomic number, and are stored in pixels as relative gray scale values or Hounsfield units (HU). We present a suite of MATLAB™ tools specifically designed for routine sediment core analysis as a means to standardize and better quantify the products of CT data collected on medical CT scanners. SedCT uses a graphical interface to process Digital Imaging and Communications in Medicine (DICOM) files, stitch overlapping scanned intervals, and create down core HU profiles in a manner robust to normal coring imperfections. Utilizing a random sampling technique, SedCT reduces data size and allows for quick processing on typical laptop computers. SedCTimage uses a graphical interface to create quality tiff files of CT slices that are scaled to a user-defined HU range, preserving the quantitative nature of CT images and easily allowing for comparison between sediment cores with different HU means and variance. These tools are presented along with examples from lacustrine and marine sediment cores to highlight the robustness and quantitative nature of this method.

Synthesis and Plasmonic Understanding of Core/Satellite and Core Shell Nanostructures

NASA Astrophysics Data System (ADS)

Ruan, Qifeng

Localized surface plasmon resonance, which stems from the collective oscillations of conduction-band electrons, endows Au nanocrystals with unique optical properties. Au nanocrystals possess extremely large scattering/absorption cross-sections and enhanced local electromagnetic field, both of which are synthetically tunable. Moreover, when Au nanocrystals are closely placed or hybridized with semiconductors, the coupling and interaction between the individual components bring about more fascinating phenomena and promising applications, including plasmon-enhanced spectroscopies, solar energy harvesting, and cancer therapy. The continuous development in the field of plasmonics calls for further advancements in the preparation of high-quality plasmonic nanocrystals, the facile construction of hybrid plasmonic nanostructures with desired functionalities, as well as deeper understanding and efficient utilization of the interaction between plasmonic nanocrystals and semiconductor components. In this thesis, I developed a seed-mediated growth method for producing size-controlled Au nanospheres with high monodispersity and assembled Au nanospheres of different sizes into core/satellite nanostructures for enhancing Raman signals. For investigating the interactions between Au nanocrystals and semiconductors, I first prepared (Au core) (TiO2 shell) nanostructures, and then studied their synthetically controlled plasmonic properties and light-harvesting applications. Au nanocrystals with spherical shapes are desirable in plasmon-coupled systems owing to their high geometrical symmetry, which facilitates the analysis of electrodynamic responses in a classical electromagnetic framework and the investigation of quantum tunneling and nonlocal effects. I prepared remarkably uniform Au nanospheres with diameters ranging from 20 nm to 220 nm using a simple seed-mediated growth method associated with mild oxidation. Core/satellite nanostructures were assembled out of differently sized

Space Station Furnace Facility. Experiment/Facility Requirements Document (E/FRD), volume 2, appendix 5

NASA Technical Reports Server (NTRS)

Kephart, Nancy

1992-01-01

The function of the Space Station Furnace Facility (SSFF) is to support materials research into the crystal growth and solidification processes of electronic and photonic materials, metals and alloys, and glasses and ceramics. To support this broad base of research requirements, the SSFF will employ a variety of furnace modules operated, regulated, and supported by a core of common subsystems. Furnace modules may be reconfigured or specifically developed to provide unique solidifcation conditions for each set of experiments. The SSFF modular approach permits the addition of new or scaled-up furnace modules to support the evolution of the facility as new science requirements are identified. The SSFF Core is of modular design to permit augmentation for enhanced capabilities. The fully integrated configuration of the SSFF will consist of three racks with the capability of supporting up to two furnace modules per rack. The initial configuration of the SSFF will consist of two of the three racks and one furnace module. This Experiment/Facility Requirements Document (E/FRD) describes the integrated facility requirements for the Space Station Freedom (SSF) Integrated Configuration-1 (IC1) mission. The IC1 SSFF will consist of two racks: the Core Rack, with the centralized subsystem equipment, and the Experiment Rack-1, with Furnace Module-1 and the distributed subsystem equipment to support the furnace.

Biotechnology Protein Expression and Purification Facility

NASA Technical Reports Server (NTRS)

2003-01-01

The purpose of the Project Scientist Core Facility is to provide purified proteins, both recombinant and natural, to the Biotechnology Science Team Project Scientists and the NRA-Structural Biology Test Investigators. Having a core facility for this purpose obviates the need for each scientist to develop the necessary expertise and equipment for molecular biology, protein expression, and protein purification. Because of this, they are able to focus their energies as well as their funding on the crystallization and structure determination of their target proteins.

The Kramer deposit of southern California--Preliminary insights on the origins of zoned lacustrine evaporite borate deposits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swihart, G.H.; McBay, E.H.; Smith, D.H.

1992-01-01

Lacustrine evaporite borate deposits span the range from mineralogically unzoned or poorly zoned to concentrically or complexly zoned types. Deposits often contain an inner ulexite or probertite (Na-Ca borates) zone and an outer colemanite (Ca borate) zone. A few deposits contain an innermost borax (Na borate) zone. Boron isotopic analyses of core material from the zoned borax-ulexite-colemanite Kramer deposit have been made with the aim of providing a better understanding of the processes of zone formation. Samples from 6 depths over a 63 foot interval in the borax zone yield a [delta] B-11 range of +0.1 to +2.3 permil. Twomore » samples in the portion of the ulexite zone below the borax zone, vertically separated from one another by 20 feet, yield identical results of [delta]B-11 = [minus]2.1 permit. Three ulexite samples from a 10 foot interval above the borax zone produced results in the range [delta]B-11 = [minus]4.6 to [minus]5.5 permil. A number of possible origins for ulexite at Kramer have been proposed: (1) primary precipitation from the lake brines; (2) postdepositional alteration of the borax zone margin by Ca-rich groundwater; (3) mixing of seeping lake brines and Ca-rich groundwater in muds around the lake. Given the small variation in B isotopic composition exhibited in the borax zone, mechanisms 1 and 2 would produce upper and lower portions of the ulexite zone with similar isotopic compositions. In the third scenario, the difference in composition of the upper and lower ulexites could be due to distance from the lake and relative proportions of seeped lake brine (B-11-rich) and clay adsorbed B (B-10-rich). Furthermore, the cotton ball form of the ulexite in this core is identical to that of ulexite forming today just beneath the surface of dry lakes in NV and CA.« less

Facile preparation of core-shell magnetic metal-organic framework nanospheres for the selective enrichment of endogenous peptides.

PubMed

Xiong, Zhichao; Ji, Yongsheng; Fang, Chunli; Zhang, Quanqing; Zhang, Lingyi; Ye, Mingliang; Zhang, Weibing; Zou, Hanfa

2014-06-10

Facile preparation of core-shell magnetic metal-organic framework nanospheres by a layer-by-layer approach is presented. The nanospheres have high surface area (285.89 cm(2)  g(-1)), large pore volume (0.18 cm(3)  g(-1)), two kinds of mesopores (2.50 and 4.72 nm), excellent magnetic responsivity (55.65 emu g(-1)), structural stability, and good dispersibility. The combination of porosity, hydrophobicity, and uniform magnetism was exploited for effective enrichment of peptides with simultaneous exclusion of high molecular weight proteins. The nanospheres were successfully applied in the selective enrichment of endogenous peptides in human serum. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oak Ridge National Laboratory Core Competencies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberto, J.B.; Anderson, T.D.; Berven, B.A.

1994-12-01

A core competency is a distinguishing integration of capabilities which enables an organization to deliver mission results. Core competencies represent the collective learning of an organization and provide the capacity to perform present and future missions. Core competencies are distinguishing characteristics which offer comparative advantage and are difficult to reproduce. They exhibit customer focus, mission relevance, and vertical integration from research through applications. They are demonstrable by metrics such as level of investment, uniqueness of facilities and expertise, and national impact. The Oak Ridge National Laboratory (ORNL) has identified four core competencies which satisfy the above criteria. Each core competencymore » represents an annual investment of at least $100M and is characterized by an integration of Laboratory technical foundations in physical, chemical, and materials sciences; biological, environmental, and social sciences; engineering sciences; and computational sciences and informatics. The ability to integrate broad technical foundations to develop and sustain core competencies in support of national R&D goals is a distinguishing strength of the national laboratories. The ORNL core competencies are: 9 Energy Production and End-Use Technologies o Biological and Environmental Sciences and Technology o Advanced Materials Synthesis, Processing, and Characterization & Neutron-Based Science and Technology. The distinguishing characteristics of each ORNL core competency are described. In addition, written material is provided for two emerging competencies: Manufacturing Technologies and Computational Science and Advanced Computing. Distinguishing institutional competencies in the Development and Operation of National Research Facilities, R&D Integration and Partnerships, Technology Transfer, and Science Education are also described. Finally, financial data for the ORNL core competencies are summarized in the appendices.« less

User Friendly Processing of Sediment CT Data: Software and Application in High Resolution Non-Destructive Sediment Core Data Sets

NASA Astrophysics Data System (ADS)

Reilly, B. T.; Stoner, J. S.; Wiest, J.; Abbott, M. B.; Francus, P.; Lapointe, F.

2015-12-01

Computed Tomography (CT) of sediment cores allow for high resolution images, three dimensional volumes, and down core profiles, generated through the attenuation of X-rays as a function of density and atomic number. When using a medical CT-Scanner, these quantitative data are stored in pixels using the Hounsfield scale, which are relative to the attenuation of X-rays in water and air at standard temperature and pressure. Here we present MATLAB based software specifically designed for sedimentary applications with a user friendly graphical interface to process DICOM files and stitch overlapping CT scans. For visualization, the software allows easy generation of core slice images with grayscale and false color relative to a user defined Hounsfield number range. For comparison to other high resolution non-destructive methods, down core Hounsfield number profiles are extracted using a method robust to coring imperfections, like deformation, bowing, gaps, and gas expansion. We demonstrate the usefulness of this technique with lacustrine sediment cores from the Western United States and Canadian High Arctic, including Fish Lake, Oregon, and Sawtooth Lake, Ellesmere Island. These sites represent two different depositional environments and provide examples for a variety of common coring defects and lithologies. The Hounsfield profiles and images can be used in combination with other high resolution data sets, including sediment magnetic parameters, XRF core scans and many other types of data, to provide unique insights into how lithology influences paleoenvironmental and paleomagnetic records and their interpretations.

The Index to Marine and Lacustrine Geological Samples (IMLGS): Linking Digital Data to Physical Samples for the Marine Community

NASA Astrophysics Data System (ADS)

Stroker, K. J.; Jencks, J. H.; Eakins, B.

2016-12-01

The Index to Marine and Lacustrine Geological Samples (IMLGS) is a community designed and maintained resource enabling researchers to locate and request seafloor and lakebed geologic samples curated by partner institutions. The Index was conceived in the dawn of the digital age by representatives from U.S. academic and government marine core repositories and the NOAA National Geophysical Data Center, now the National Centers for Environmental Information (NCEI), at a 1977 meeting convened by the National Science Foundation (NSF). The Index is based on core concepts of community oversight, common vocabularies, consistent metadata and a shared interface. The Curators Consortium, international in scope, meets biennially to share ideas and discuss best practices. NCEI serves the group by providing database access and maintenance, a list server, digitizing support and long-term archival of sample metadata, data and imagery. Over three decades, participating curators have performed the laborious task of creating and contributing metadata for over 205,000 sea floor and lake-bed cores, grabs, and dredges archived in their collections. Some partners use the Index for primary web access to their collections while others use it to increase exposure of more in-depth institutional systems. The IMLGS has a persistent URL/Digital Object Identifier (DOI), as well as DOIs assigned to partner collections for citation and to provide a persistent link to curator collections. The Index is currently a geospatially-enabled relational database, publicly accessible via Web Feature and Web Map Services, and text- and ArcGIS map-based web interfaces. To provide as much knowledge as possible about each sample, the Index includes curatorial contact information and links to related data, information and images : 1) at participating institutions, 2) in the NCEI archive, and 3) through a Linked Data interface maintained by the Rolling Deck to Repository R2R. Over 43,000 International Geo

Palaeoenvironments during MIS 3 and MIS 2 inferred from lacustrine intercalations in the loess-palaeosol sequence at Bobingen (southern Germany)

NASA Astrophysics Data System (ADS)

Mayr, Christoph; Matzke-Karasz, Renate; Stojakowits, Philipp; Lowick, Sally E.; Zolitschka, Bernd; Heigl, Tanja; Mollath, Richard; Theuerkauf, Marian; Weckend, Marc-Oliver; Bäumler, Rupert; Gregor, Hans-Joachim

2017-12-01

Recently exposed loess-palaeosol sequences in the northern Alpine foreland close to Bobingen (southern Germany) were investigated with a multi-proxy approach combining isotopic, geochemical, lithological, and micropalaeontological methods. Luminescence ages date the sections into the Middle and Upper Würmian periods corresponding to Marine Isotope Stages 3 and 2. A gleyic soil horizon at the base was dated to 45 ka and provided a palynoflora dominated by Poaceae, Cyperaceae, and Pinus, as well as frequent aquatic taxa. Lacustrine conditions prevailed after the gley formation until 30 ka, providing a comparatively diverse lacustrine fauna dominated by aquatic gastropods and the ostracod species Candona candida. At the transition to the Upper Würm, climatic conditions became harsh, indicated by accelerated deposition of more coarse-grained loess, organic geochemical indicators, and scarceness of biotic remains. Two tundra-gley horizons in the Upper Würm point to short phases of climatic amelioration with higher humidity also evidenced by reoccurrence of ostracod and aquatic gastropod remains. We propose that these climatic ameliorations were coincident with the Greenland interstadials 4 and 2.

Lacustrine records of continental climate in northwest Greenland through the Holocene and Last Interglacial

NASA Astrophysics Data System (ADS)

McFarlin, J. M.; Axford, Y.; Osburn, M. R.; Lasher, G. E.; Francis, D. R.; Kelly, M. A.; Osterberg, E. C.

2015-12-01

Lake sediment records provide opportunities for high-resolution observations of paleoclimate that help to place modern climate change in geologic context. Here we present a terrestrial record of July air temperature for northwest Greenland (Nunatarssuaq, ~25 km east of the Thule Air Base) through the Holocene and a prior warm period, inferred from subfossil insect remains (Chironomidae) preserved in lacustrine sediments. In addition, we discuss ongoing work in characterizing the sources and isotopic composition of leaf waxes preserved in the same sediments. Multiple parallel sediment cores were collected in the summers of 2012 and 2014 from Wax Lips Lake (informal name), a non-glacial lake situated <2 km from the current margin of the Greenland Ice Sheet. Radiocarbon ages were obtained on aquatic mosses from intact laminae, and indicate that the record spans the Holocene, beginning at ~10.4 ka, as well as an interval beyond the range of 14C (>44 ka) and thus predates the Last Glacial Maximum (LGM). Our results demonstrate temperatures warmer than present through the early and mid Holocene followed by cooling in the late Holocene. Material that pre-dates the LGM contains insect assemblages indicating temperatures warmer than the warmest millennia of the Holocene. We interpret this material as most likely dating to the Last Interglacial Period (MIS 5). Along with assemblages of Chironomidae, we find subfossil Chaoboridae in one section of the pre-LGM sediments, suggesting exceptionally warm conditions based upon the distribution of modern-day Chaoborus. We find abundant n-alkanes and n-acids are preserved in the Holocene and pre-LGM sediments, allowing for complementary compound-specific δD analyses and identification of organic matter source in addition to chironomid derived temperature records.

Application of Lacustrine Biomarkers to Reconstruct Late Holocene Temperature Change in the Saskatchewan Prairies.

NASA Astrophysics Data System (ADS)

Cavazzin, B.; Toney, J. L.; Pearson, E. J.; Schouten, S.; Leavitt, P.; Haig, H.

2016-12-01

Extreme hydrological events such as prolonged droughts are among Canada's costliest natural calamities resulting in disastrous impacts on agriculture, forestry, industry, and ecosystems. Investigations into climate variations prior to significant anthropogenic modification are essential to build effective projection models and adaptation strategies needed to reduce economic, social and environmental vulnerability within the prairies eco-region. In this study we use organic geochemical analysis of lipids produced by bacteria, archaea and algae in lake and catchment sediments. These organic compounds are highly resistant to degradation and accumulate in the sediments as geochemical fossils or biomarkers. In particular we focus on Glycerol Dialkyl Glycerol Tetraethers (GDGT) biomarkers which are ubiquitous in soils and lacustrine environments and can be applied as quantitative temperature proxies in regions of the world where other proxies cannot be used. The aim of this study is to examine the relationship between GDGT distribution and temperature and assess the potential for establishing a GDGT-based paleothermometer for the Canadian prairies lakes. Our training set includes GDGT data from core-top sediments from 105 lakes across spanning a 5° latitudinal gradient and spring surface water temperature gradient of about 9°C. We identified 30 known bacterial and archaeal GDGTs, including the novel archaeal tetraether lipids with a cyclohexyl ring. These compounds are present in varying proportions in all the lakes investigated, suggesting a broad range of GDGT inputs and also potential in-situ production. We analysed the relationships between individual GDGT compounds against temperature, pH, conductivity, water depth and other environmental variables. We also examined previously published GDGT-environment indices in order to test the applicability of previously developed GDGT-based paleotemperature calibrations to the prairies lakes and assess whether a new

Facile green in situ synthesis of Mg/CuO core/shell nanoenergetic arrays with a superior heat-release property and long-term storage stability.

PubMed

Zhou, Xiang; Xu, Daguo; Zhang, Qiaobao; Lu, Jian; Zhang, Kaili

2013-08-14

We report a facile green method for the in situ synthesis of Mg/CuO core/shell nanoenergetic arrays on silicon, with Mg nanorods as the core and CuO as the shell. Mg nanorods are first prepared by glancing angle deposition. CuO is then deposited around the Mg nanorods by reactive magnetron sputtering to realize the core/shell structure. Various characterization techniques are used to investigate the prepared Mg/CuO core/shell nanoenergetic arrays, including scanning electron microscopy, transmission electron microscopy, X-ray energy dispersive spectroscopy, X-ray diffraction, and thermal analysis. Uniform mixing and intimate contact between the Mg nanorods and CuO are confirmed from both visual inspection of the morphological images and analyses of the heat-release curves. The nanoenergetic arrays exhibit a low-onset reaction temperature (∼300 °C) and high heat of reaction (∼3400 J/g). Most importantly, the nanoenergetic arrays possess long-term storage stability resulting from the stable CuO shell. This study provides a potential general strategy for the synthesis of various Mg nanorod-based stable nanoenergetic arrays.

Isotopic identification of the source of methane in subsurface sediments of an area surrounded by waste disposal facilities

USGS Publications Warehouse

Hackley, Keith C.; Liu, Chao-Li; Trainor, D.

1999-01-01

The major source of methane (CH4) in subsurface sediments on the property of a former hazardous waste treatment facility was determined using isotopic analyses measured on CH4 and associated groundwater. The site, located on an earthen pier built into a shallow wetland lake, has had a history of waste disposal practices and is surrounded by landfills and other waste management facilities. Concentrations of CH4 up to 70% were found in the headspace gases of several piezometers screened at 3 different depths (ranging from 8 to 17 m) in lacustrine and glacial till deposits. Possible sources of the CH4 included a nearby landfill, organic wastes from previous impoundments and microbial gas derived from natural organic matter in the sediments. Isotopic analyses included ??13C, ??D, 14C, and 3H on select CH4 samples and ??D and ??18O on groundwater samples. Methane from the deepest glacial till and intermediate lacustrine deposits had ??13C values from -79 to -82???, typical of natural 'drift gas' generated by microbial CO2-reduction. The CH4 from the shallow lacustrine deposits had ??13C values from -63 to -76???, interpreted as a mixture between CH4 generated by microbial fermentation and the CO2-reduction processes within the subsurface sediments. The ??D values of all the CH4 samples were quite negative ranging from -272 to -299???. Groundwater sampled from the deeper zones also showed quite negative ??D values that explained the light ??D observed for the CH4. Radiocarbon analyses of the CH4 showed decreasing 14C activity with depth, from a high of 58 pMC in the shallow sediments to 2 pMC in the deeper glacial till. The isotopic data indicated the majority of CH4 detected in the fill deposits of this site was microbial CH4 generated from naturally buried organic matter within the subsurface sediments. However, the isotopic data of CH4 from the shallow piezometers was more variable and the possibility of some mixing with oxidized landfill CH4 could not be completely

Evaporation Of Hanford Waste Treatment Plant Direct Feed Low Activity Waste Effluent Management Facility Core Simulant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamson, D.; Nash, C.; Mcclane, D.

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Melter Off-Gas Condensate, LMOGC) from the off-gas system. The baseline plan for disposition of this stream during full WTP operations is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation, and recycled to the LAW vitrification facility. However, during the Direct Feed LAW (DFLAW) scenario, planned disposition of this stream is to evaporate it in a new evaporator, in the Effluent Management Facility (EMF), and then return it tomore » the LAW melter. It is important to understand the composition of the effluents from the melter and new evaporator, so that the disposition of these streams can be accurately planned and accommodated. Furthermore, alternate disposition of the LMOGC stream would eliminate recycling of problematic components, and would reduce the need for closely integrated operation of the LAW melter and the Pretreatment Facilities. Long-term implementation of this option after WTP start-up would decrease the LAW vitrification mission duration and quantity of glass waste, amongst the other operational complexities such a recycle stream presents. In order to accurately plan for the disposition path, it is key to experimentally determine the fate of contaminants. To do this, testing is needed to accurately account for the buffering chemistry of the components, determine the achievable evaporation end point, identify insoluble solids that form, and determine the distribution of key regulatory-impacting constituents. The LAW Melter Off-Gas Condensate stream will contain components that are volatile at melter temperatures, have limited solubility in the glass waste form, and represent a materials corrosion concern, such as halides and sulfate. Because this stream will recycle within WTP, these components will accumulate in the Melter

Using Seismic Reflection Analysis of Lacustrine Sediment Stratigraphy to Reconstruct 40,000 Years of Northern Hemisphere Andean Hydroclimate

NASA Astrophysics Data System (ADS)

Gibson, D. K.; Bird, B. W.; Wattrus, N. J.; Escobar, J.; Fonseca, H.; Velasco, F.; Polissar, P. J.

2017-12-01

Geophysical analysis of lacustrine seismic stratigraphy at Laguna de Tota (hereafter "Tota"), Boyaca, Colombia, provides a record of lake level fluctuations that ranges from the Late Quaternary to the present. Changes in Tota's volume indicated by off-lap and on-lap sequences show that regional hydroclimate varied considerably during at least the last 40 Ka. Modern lake level variability at Tota has been directly linked to the El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO), suggesting that past lake level changes identified in CHIRP seismic data may provide insight into past Pacific atmosphere-ocean dynamics. Here, we use high-resolution CHIRP data spanning the top 15 meters of sediment column and a preliminary age model based on Holocene sedimentation rates to investigate lake level variability over the past 40 Ka. Our data demonstrates that lake levels at Tota were generally lower between 40 and 30 Ka, experienced rapid and extreme fluctuations between 30 and 20 Ka (including the lowest recorded lake level at Tota during the LGM at 22 Ka), and gradually rose to the present day high stand between 20 and 0 Ka. Although the CHIRP data indicate significant late Quaternary lake level fluctuations, the timing and duration of these events needs to be more firmly constrained with additional investigations combining sediment core collection and analysis, geochronology, and other lake level proxies. Future work combining these methods holds tremendous potential in terms of reconstructing Late Quaternary atmosphere-ocean cycles.

Determining earthquake recurrence intervals from deformational structures in young lacustrine sediments

USGS Publications Warehouse

Sims, John D.

1975-01-01

Examination of the silty sediments in the lower Van Normal reservoir after the 1971 San Fernando, California earthquake revealed three zones of deformational structures in the 1-m-thick sequence of sediments exposed over about 2 km2 of the reservoir bottom. These zones are correlated with moderate earthquakes that shook the San Fernando area in 1930, 1952, and 1971. The success of this study, coupled with the experimental formation of deformational structures similar to those of the Van Norman reservoir, led to a search for similar structures in Pleistocene and Holocene lakes and lake sediments in other seismically active areas. Thus, studies have been started in Pleistocene and Holocene silty and sandy lake sediments in the Imperial Valley, southeastern California; Clear Lake, in northern California; and the Puget Sound area of Washington. The Imperial Valley study has yielded spectacular results: five zones of structures in the upper 10 m of Late Holocene sediments near Brawley have been correlated over an area of approximately 100 km2, using natural outcrops. These structures are similar to those of the Van Norman reservoir and are interpreted to represent at least five moderate to large earthquakes that affected the southern Imperial Valley area during Late Holocene time. The Clear Lake study has provided ambiguous results with respect to determination of earthquake recurrence intervals because the cores studied are in clayey rich in organic material sediments that have low liquefaction potential. A study of Late Pleistocene varved glacio-lacustrine sediments has been started in the Puget Sound area of Washington, and thirteen sites have been examined. One has yielded 18.75 m of sediments that contains 1,804 varves and fourteen deformed zones interpreted as being caused by earthquake, because they are identical to structures formed experimentally by simulated seismic shaking. Correlation of deformational structures with seismic events is based on:(1) proximity

Transformation of marine sediment to paddy soil: Primary marine, lacustrine, and land plant lipids

NASA Astrophysics Data System (ADS)

Mueller-Niggemann, Cornelia; Cao, Zhihong; Schwark, Lorenz

2010-05-01

More than fifty percent of the world's population feeds on rice. The continuous population increase and urban sprawl leads to an ever-increasing demand for new rice cultivation area, in particular China. For centuries suitable coastal areas in China have been exploited for land reclamation, i.e. conversion of coastal marine and lacustrine marshlands into rice paddy fields. Flooded rice paddies are considered one of the major biogenic sources of methane into the atmospheric. Methane is thought to be about 30 times more efficient as greenhouse gas, when compared to carbon dioxide. Overall, rice fields are assumed to contribute app. 10-25% to global CH4 production. It is thus paramount importance to study the effects of increasing rice cultivation and land reclamation in China. For global carbon cycle investigation, it is crucial whether paddy soils, due to their large extent and higher carbon turnover, serve as carbon (CO2) sinks or sources. Here we present results from a chronosequence study of paddy soils with different and well known starting dates of cultivation, in the Zhejiang province (Yangtze River delta) by land reclamation through the building of protective dikes over the past 2000 years. Two end members of natural sediments subjected to land reclamation, a marine tidal mudflat in the Yangtze delta and a coastal lake, represent the substrate on which the paddy soil evolution started. Dike systems were constructed 2000, 1000, 700, 300, 100, and 50 years before present. We are thus able to follow the evolution of rice paddy soils developed on marine sediments using eight well defined tie-points. This chronosequence is then used for assessing the relative proportion of primary marine or lacustrine organic matter preserved in present day soils and to identify the amount and composition of organic matter added since cultivation started. Paddy soil management introduces rice plants debris and exudates as well as rice-associated microbial biomass (covered in a

Reconstruction of a saline, lacustrine carbonate system (Priabonian, St-Chaptes Basin, SE France): Depositional models, paleogeographic and paleoclimatic implications

NASA Astrophysics Data System (ADS)

Lettéron, Alexandre; Hamon, Youri; Fournier, François; Séranne, Michel; Pellenard, Pierre; Joseph, Philippe

2018-05-01

A 220-m thick carbonate-dominated succession has been deposited in shallow-water, saline lake environments during the early to middle Priabonian (MP17A-MP18 mammal zones) in the Saint-Chaptes Basin (south-east France). The palaeoenvironmental, paleoclimatic and palaeogeographic significance of such saline lake carbonates has been deciphered on the basis of a multi-proxy analyses including: 1) depositional and diagenetic features; 2) biological components (molluscs, benthic foraminifera, characean gyrogonites, spores and pollens); 3) carbon and oxygen stable isotopes; 4) trace elements; and 5) clay mineralogy. Five stages of lacustrine system evolution have been identified: 1) fresh-water closed lake under dry climate (unit U1); 2) fresh to brackish water lacustrine deltaic system with a mixed carbonate-siliciclastic sedimentation under relatively wet climatic conditions (unit U2); 3) salt-water lacustrine carbonate system under humid climatic setting (unit U3); 4) evaporitic lake (unit U4); and 5) closed lake with shallow-water carbonate sedimentation under subtropical to Mediterranean climate with dry seasons (unit U5). Upper Eocene aridification is evidenced to have started as early as the earliest Priabonian (unit U1: MP17A mammal zone). A change from humid to dryer climatic conditions is recorded between units U3 and U4. The early to middle Priabonian saline lake is interpreted as an athalassic (inland) lake that have been transiently connected with neighboring salt lakes influenced by seawater and/or fed with sulfates deriving from recycling of evaporites. Maximum of connection with neighboring saline lakes (Mormoiron Basin, Camargue and Central grabens, Hérault Basin) likely occurred during unit U3 and at the base of unit U5. The most likely sources of salts of these adjacent basins are: 1) Triassic evaporites derived from salt-diapirs (Rhône valley) or from paleo-outcrops located east of the Durance fault or offshore in the Gulf of Lion; or 2) marine

Sedimentary Basin Structure of the Hadar Formation's Lacustrine-Dominated Depocenter (Ledi-Geraru, Afar, Ethiopia) and its Relevance for Investigating Hominin Paleoenvironments

NASA Astrophysics Data System (ADS)

Dimaggio, E. N.; Campisano, C. J.; Arrowsmith, J. R.; Dupont-Nivet, G.; Johnson, R. A.; Warren, M. B.

2008-12-01

Sedimentary sequences preserved in East African rift basins record the long-term response of past depositional environments to climatic and tectonic forcing. Motivations for recent field investigations at the Ledi-Geraru site, part of the greater Hadar sedimentary basin in the Afar region of Ethiopia, stem from a need to characterize local basin structure and expand and refine interpretations of the complex mid-late Pliocene history of local and regional-scale landscape change during a time of critical importance for understanding hominin evolution. Detailed geologic mapping (1:7,000), measured stratigraphic sections, and seismic reflection surveys provide the datasets necessary for basin evaluation. The Ledi-Geraru sedimentary sequence (>250m thick) exposes nearly the entirety of the hominin-bearing Hadar Formation of west- central Afar. Both primary unmodified lake deposits and intervals modified by subsequent subaerial exposure and pedogenesis are well-exposed. The lacustrine-dominated signature is indicated by the prevalence of laminated silty clays that contain leaf impressions, fish scales, and gastropod shells, undisturbed laminated diatomite and clays, and pedogenically modified diatomaceous silts. The sequence is generally flat lying, with low bedding dips ranging from 0-2° NNW to <1° NNE and minor NNW trending faults with <5 m vertical offset. Whereas coeval fluvio-lacustrine sediments associated with hominin and archaeological sites west of Ledi-Geraru (e.g., Hadar and Gona) are marked by comparatively slow and episodic sedimentation, sedimentation rates in the Ledi-Geraru sequence are extremely high and consistent, on the order of ~0.9-1.0mm/yr. Laterally extensive tephra marker beds and paleomagnetic records provide excellent age control for sedimentation rate estimates and correlation to nearby fossil-rich sequences. As the Hadar basin sediments preserve a rich paleoanthropologic and archaeological record, this work provides the geologic framework

Facile fabrication of core-in-shell particles by the slow removal of the core and its use in the encapsulation of metal nanoparticles.

PubMed

Choi, Won San; Koo, Hye Young; Kim, Dong-Yu

2008-05-06

Core-in-shell particles with controllable core size have been fabricated from core-shell particles by means of the controlled core-dissolution method. These cores in inorganic shells were employed as scaffolds for the synthesis of metal nanoparticles. After dissolution of the cores, metal nanoparticles embedded in cores were encapsulated into the interior of shell, without any damage or change. This article describes a very simple method for deriving core-in-shell particles with controllable core size and encapsulation of nanoparticles into the interior of shell.

Abiotically-formed, primary dolomite in the mid-Eocene lacustrine succession at Gebel El-Goza El-Hamra, NE Egypt: An approach to the role of smectitic clays

NASA Astrophysics Data System (ADS)

Wanas, H. A.; Sallam, E.

2016-08-01

This study discusses the role of smectitic clays in the formation of an abiotic (physio-chemical) primary dolomite within an evaporative alkaline-saline marginal lake system, in the absence of carbonate precursor and microbes. The present work has been achieved in terms of textural, mineralogical, and geochemical characteristics of dolostones in the Mid-Eocene (Bartonian) lacustrine succession cropping out at Gebel El-Goza El-Hamra (Shabrawet area, NE Egypt). This lacustrine succession is 15-16 m thick, and made up of alternating horizontal beds of dolostone, marlstone and mudrock that show some pedogenic and subaerial exposure features. The dolostones are composed mainly of dolomite (60-90%), smectite (20-30%) and quartz grains (5-10%). The dolomite comprises fine-crystalline rhombs to micro-spherical crystals with no obvious relics of microbial activity and/or carbonate precursor. It is, ordered, nearly stoichiometric (with 46-50% mole of MgCO3) and has δ18O and δ13C values ranging from + 0.44 to + 2.96 VPDB ‰, and 0.93 to - 8.95 VPDB ‰, respectively. The smectite occurs as thin mats that are commonly intergrown and associated with dolomite. Mineralogical, textural and stable isotopic results of the dolomite indicated that the dolomite was formed as an abiotic primary precipitate in alkaline saline lacustrine systems. In this respect, the gel-like highly viscous smectitic medium plus progressive CO2 degassing, elevated evaporation, low sedimentation rate, low sulphates level and alkaline soil solution lowered the kinetic barriers of dolomite precipitation from solution and promoted the incorporation of Mg2 + in the structure of dolomite. Consequently, the presence of smectitic clays in evaporative saline lakes is significant for dolomite formation because they can generate a gel-like highly viscous medium and provide Mg2 + that can facilitate the physcio-chemical precipitation of primary dolomite from solution at ambient temperatures. However, more work is

Facile synthesis of 3D few-layered MoS2 coated TiO2 nanosheet core-shell nanostructures for stable and high-performance lithium-ion batteries

NASA Astrophysics Data System (ADS)

Chen, Biao; Zhao, Naiqin; Guo, Lichao; He, Fang; Shi, Chunsheng; He, Chunnian; Li, Jiajun; Liu, Enzuo

2015-07-01

Uniform transition metal sulfide deposition on a smooth TiO2 surface to form a coating structure is a well-known challenge, caused mainly due to their poor affinities. Herein, we report a facile strategy for fabricating mesoporous 3D few-layered (<4 layers) MoS2 coated TiO2 nanosheet core-shell nanocomposites (denoted as 3D FL-MoS2@TiO2) by a novel two-step method using a smooth TiO2 nanosheet as a template and glucose as a binder. The core-shell structure has been systematically examined and corroborated by transmission electron microscopy, scanning transmission electron microscopy, and X-ray photoelectron spectroscopy analyses. It is found that the resultant 3D FL-MoS2@TiO2 as a lithium-ion battery anode delivers an outstanding high-rate capability with an excellent cycling performance, relating to the unique structure of 3D FL-MoS2@TiO2. The 3D uniform coverage of few-layered (<4 layers) MoS2 onto the TiO2 can remarkably enhance the structure stability and effectively shortens the transfer paths of both lithium ions and electrons, while the strong synergistic effect between MoS2 and TiO2 can significantly facilitate the transport of ions and electrons across the interfaces, especially in the high-rate charge-discharge process. Moreover, the facile fabrication strategy can be easily extended to design other oxide/carbon-sulfide/oxide core-shell materials for extensive applications.Uniform transition metal sulfide deposition on a smooth TiO2 surface to form a coating structure is a well-known challenge, caused mainly due to their poor affinities. Herein, we report a facile strategy for fabricating mesoporous 3D few-layered (<4 layers) MoS2 coated TiO2 nanosheet core-shell nanocomposites (denoted as 3D FL-MoS2@TiO2) by a novel two-step method using a smooth TiO2 nanosheet as a template and glucose as a binder. The core-shell structure has been systematically examined and corroborated by transmission electron microscopy, scanning transmission electron microscopy

Fine-grained sediment gravity flow deposits induced by flood and lake slope failure events: examples of lacustrine varved sediments in Japan

NASA Astrophysics Data System (ADS)

Ishihara, Yoshiro; Sasaki, Yasunori; Sasaki, Hana; Onishi, Yuri

2016-04-01

Fine-grained sediment gravity flow deposits induced by flood and lake slope failure events are frequently intercalated in lacustrine successions. When sediment gravity flow deposits are present in varved sediments, it is suggested that they provide valuable information about sediment gravity flows, because they can easily trace laterally and can give the magnitude of erosion and recurrence interval of events. In addition, because large sedimentary bodies of stacked sediment gravity flow deposits in varved sediments of a calm lake are not suggested, a relatively simple depositional environment is expected. In the present study, we analysed sedimentary facies of sediment gravity flow deposits in varved lacustrine diatomites in the Middle Pleistocene Hiruzenbara and Miyajima formations in Japan, and concluded a depositional model of the lacustrine sediment gravity flow deposits. Varved diatomites: The Hiruzenbara Fm., a dammed lake fill as foots of Hiruzen Volcanos, is deposited during an interglacial period during MIS12 to 15. Varves of ca. 8000 yr were measured in a 20 m intercalating flood and lake slope failure-induced sediment gravity flow deposits. The Miyajima Fm., distributed in a paleo-caldera lake in NE Japan, includes many sediment gravity flow deposits possibly originated from fandeltas around the lake. These formations have differences in their depositional setting; the Hiruzebara Fm. was deposited in a large lake basin, whereas the Miyajima Fm. was deposited in a relatively small basin. Because of the depositional setting, intercalation of volcaniclastics is dominant in the Miyajima Fm. Lacustrine sediment gravity flow deposits: Sediment gravity flow deposits in both formations can be classified into flood- and lake slope failure-induced types based on the sedimentary facies. Composites of the both types are also found. Flood-induced types comprise fine-grained silts dominated by carbonaceous fragments, whereas lake slope failure-induced types are

Chapter F: Preliminary Bibliography of Lacustrine Diatomite Deposits in the Western United States and Related Topics

USGS Publications Warehouse

Bolm, Karen S.; Wallace, Alan R.; Moyle, Phillip R.; Bliss, James D.; Orris, Greta J.

2003-01-01

Introduction As part of the assessment of lacustrine diatomite resources in the Western United States (fig. 1), U.S. Geological Survey (USGS) project members conducted a review of literature relating to the formation, location, and nature of deposits in the study area. This preliminary bibliography consists of selected publications to identify, locate, and describe the deposits to be studied, to characterize common geologic factors about the deposits, and to better understand the factors that control their formation, preservation, or destruction. The bibliography also serves as a resource for other workers to research the topic. References included in the preliminary bibliography were gathered by searching existing bibliographic data bases and library collections. Project researchers also contributed references that they found during the course of their work. This bibliography should be considered a working document that will grow as research and literature searches continue. Clearly, many significant publications may be missing from this preliminary list; therefore, USGS staff members intend to issue a revised bibliography as project work progresses. To assure completeness, input from other researchers and industry is welcome. Although the focus of this bibliography is lacustrine diatomite deposits of the Western United States, additional references that provide a foundation of knowledge for the study of diatomites, diatoms, and diatom-related processes (ecology, geology, geochemistry) and for the uses and behavior of diatomite have also been included. An index of keywords has been added to this bibliography, designed to help the user locate reports by topic or by geographic location. The letter 'A' following a number indicates that the report referenced is an abstract.

Using a network of core samples to explore hydroclimatic proxy relationships within the sediments of an alpine, glacier-fed lake

NASA Astrophysics Data System (ADS)

Hodder, Kyle; Suchan, Jared

2015-04-01

Spatial and temporal variability of recent lacustrine sedimentation rates are examined for glacier-fed Mud Lake, in the Monashee Mountains of British Columbia. Clastic varve sequences in alpine, glacier-fed environments have been linked elsewhere with temperature (summer, annual), precipitation (autumn, total snowpack), and runoff (glacial, floods), and the use of varved sediments as hydroclimatic proxies is well-developed from single, but rarely multiple, core samples. In this study, a network of sediment cores (n=63) were extracted using a dense grid-sampling scheme within the 2.5 km2 distal lake basin to assess varve thickness spatially, and through time. A radioisotope profile, sediment traps and repeated coring among multiple years were used to calibrate varve-years with calendar years. Measurements of varve thickness, and sub-annual laminae thickness, were collated among cores and spanned the period 1919 - 2013 AD. The resulting five-dimensional dataset (easting, northing, depth, varve/sub-laminae thickness, time) provides a unique opportunity to explore lacustrine sedimentation. Two clear trends emerge: a general down-lake trend in thickness among most years, which is punctuated by atypical years in which thicker varves appeared in only specific portions of the lake. In the latter case, thick varves appeared either (a) along the north (right-hand) side of the lake where inflow 'hugs' the shoreline, or (b) in the deepest, distal portion of the basin. In both cases, however, atypical varves of type (a) or (b) only punctuate the general down-lake trend in thickness that develops during most years. The clear implication is that sedimentation patterns, and rates, can (but do not always) differ between years and between points in Mud Lake: there is no 'single optimum' site for a core sample. To illustrate the potential consequences on hydroclimate proxy/inference, we show how the statistical relationships between hydroclimatic records and varve thickness vary

78 FR 47154 - Core Principles and Other Requirements for Swap Execution Facilities; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-05

... COMMODITY FUTURES TRADING COMMISSION 17 CFR Part 37 RIN 3038-AD18 Core Principles and Other... this chapter. Appendix B to Part 37--Guidance on, and Acceptable Practices in, Compliance With Core Principles [Corrected] 2. On page 33600, in the second column, under the heading Core Principle 3 of Section...

Sources and proxy potential of long chain alkyl diols in lacustrine environments

NASA Astrophysics Data System (ADS)

Rampen, Sebastiaan W.; Datema, Mariska; Rodrigo-Gámiz, Marta; Schouten, Stefan; Reichart, Gert-Jan; Sinninghe Damsté, Jaap S.

2014-11-01

Long chain 1,13- and 1,15-alkyl diols form the base of a number of recently proposed proxies used for climate reconstruction. However, the sources of these lipids and environmental controls on their distribution are still poorly constrained. We have analyzed the long chain alkyl diol (LCD) composition of cultures of ten eustigmatophyte species, with three species from different families grown at various temperatures, to identify the effect of species composition and growth temperature on the LCD distribution. The results were compared with the LCD distribution of sixty-two lake surface sediments, and with previously reported LCD distributions from marine environments. The different families within the Eustigmatophyceae show distinct LCD patterns, with the freshwater family Eustigmataceae most closely resembling LCD distributions in both marine and lake environments. Unlike the other two eustigmatophyte families analyzed (Monodopsidaceae and Goniochloridaceae), C28 and C30 1,13-alkyl diols and C30 and C32 1,15-alkyl diols are all relatively abundant in the family Eustigmataceae, while the mono-unsaturated C32 1,15-alkyl diol was below detection limit. In contrast to the marine environment, LCD distributions in lakes did not show a clear relationship with temperature. The Long chain Diol Index (LDI), a proxy previously proposed for sea surface temperature reconstruction, showed a relatively weak correlation (R2 = 0.33) with mean annual air temperature used as an approximation for annual mean surface temperature of the lakes. A much-improved correlation (R2 = 0.74, p-value <0.001) was observed applying a multiple linear regression analysis between LCD distributions and lake temperatures reconstructed using branched tetraether lipid distributions. The obtained regression model provides good estimates of temperatures for cultures of the family Eustigmataceae, suggesting that algae belonging to this family have an important role as a source for LCDs in lacustrine

17 CFR 37.1400 - Core Principle 14-System safeguards.

Code of Federal Regulations, 2014 CFR

2014-04-01

... procedures, and automated systems, that: (1) Are reliable and secure; and (2) Have adequate scalable capacity... 17 Commodity and Securities Exchanges 1 2014-04-01 2014-04-01 false Core Principle 14-System... SWAP EXECUTION FACILITIES System Safeguards § 37.1400 Core Principle 14—System safeguards. The swap...

Trace fossils from Jurassic lacustrine turbidites of the Anyao Formation (Central China) and their environmental and evolutionary significance

USGS Publications Warehouse

Buatois, Luis A.; Mángano, M. Gabriela; Wu, Xiantao; Zhang, Guocheng

1996-01-01

The Lower Jurassic Anyao Formation crops out near Jiyuan city, western Henan Province, central China. It is part of the infill of the nonmarine early Mesozoic Jiyuan‐Yima Basin. In the Jiyuan section, this unit is about 100 m thick and consists of laterally persistent, thin and thick‐bedded turbidite sandstones and mudstones displaying complete and base‐or top‐absent Bouma sequences, and thick‐bedded massive sandstones. The Anyao Formation records sedimentation within a lacustrine turbidite system developed in a pull‐apart basin. Processes involved include high and low density turbidity currents, sometimes affected by liquefaction or fluidization. Facies analysis suggests that this succession is formed by stacked aggradational turbidite lobes. The absence of thick mudstone packages indicates that background sedimentation was subordinate to high frequency turbidite deposition.The Anyao Formation hosts a moderately diverse ichnofauna preserved as hypichnial casts on the soles of thin‐bedded turbidite sandstones. The ichnofauna consists of Cochlichnus anguineus, Hel‐minthoidichnites tenuis, Helminthopsis abeli, H. hieroglyphica, Mono‐morphichnus lineatus, Paracanthorhaphe togwunia, Tuberculichnus vagans, Vagorichnus anyao, tiny grazing trails, and irregularly branching burrows. Vagorichnus anyao occurs not only as a discrete trace, but also as a compound ichnotaxon intergrading with Gordia marina and Tuberculichnus vagans. Both predepositional and post‐depositional traces are present on the soles of turbidites.This ichnofauna comprises both feeding and grazing traces produced by a deposit‐feeding lacustrine benthic biota. Crawling traces are rare. Although certain ichnofossils (e.g. V. anyao, P. togwunia) show overall similarities with deep‐sea agrichnia, they differ in reflecting remarkably less specialized feeding strategies, displaying overcrossing between specimens (and to a lesser extent, self‐crossing), and in the case of V�

Core-Noise

NASA Technical Reports Server (NTRS)

Hultgren, Lennart S.

2010-01-01

This presentation is a technical progress report and near-term outlook for NASA-internal and NASA-sponsored external work on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system level noise metrics for the 2015, 2020, and 2025 timeframes; the emerging importance of core noise and its relevance to the SFW Reduced-Noise-Aircraft Technical Challenge; the current research activities in the core-noise area, with some additional details given about the development of a high-fidelity combustion-noise prediction capability; the need for a core-noise diagnostic capability to generate benchmark data for validation of both high-fidelity work and improved models, as well as testing of future noise-reduction technologies; relevant existing core-noise tests using real engines and auxiliary power units; and examples of possible scenarios for a future diagnostic facility. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Noise-Aircraft Technical Challenge aims to enable concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical for enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor designs could increase

Plum Brook Reactor Facility Control Room during Facility Startup

NASA Image and Video Library

1961-02-21

Operators test the National Aeronautics and Space Administration’s (NASA) Plum Brook Reactor Facility systems in the months leading up to its actual operation. The “Reactor On” signs are illuminated but the reactor core was not yet ready for chain reactions. Just a couple weeks after this photograph, Plum Brook Station held a media open house to unveil the 60-megawatt test reactor near Sandusky, Ohio. More than 60 members of the print media and radio and television news services met at the site to talk with community leaders and representatives from NASA and Atomic Energy Commission. The Plum Brook reactor went critical for the first time on the evening of June 14, 1961. It was not until April 1963 that the reactor reached its full potential of 60 megawatts. The reactor control room, located on the second floor of the facility, was run by licensed operators. The operators manually operated the shim rods which adjusted the chain reaction in the reactor core. The regulating rods could partially or completely shut down the reactor. The control room also housed remote area monitoring panels and other monitoring equipment that allowed operators to monitor radiation sensors located throughout the facility and to scram the reactor instantly if necessary. The color of the indicator lights corresponded with the elevation of the detectors in the various buildings. The reactor could also shut itself down automatically if the monitors detected any sudden irregularities.

Impacts of flamingos on saline lake margin and shallow lacustrine sediments in the Kenya Rift Valley

NASA Astrophysics Data System (ADS)

Scott, Jennifer J.; Renaut, Robin W.; Owen, R. Bernhart

2012-11-01

Studies of modern, Holocene, and Pleistocene sediments around saline to hypersaline, alkaline Lake Bogoria and Lake Magadi show that evidence of flamingo activity in marginal areas of these lakes is nearly ubiquitous. Flamingos produce discrete structures such as webbed footprints (~ 9 cm long, ~ 11 cm wide) and nest mounds (~ 30 cm wide, ~ 20 cm high), and they also extensively rework sediments in delta front, delta plain, and shoreline areas. Large (~ 0.5-2 cm in diameter), pinched, 'bubble pores' and ped-like mud clumps are formed by the trampling and churning of wet clay-rich sediments in these settings. Flamingo nest mounds, although superficially similar to some thrombolite mounds, are typically internally structureless, unless formed on pre-existing sediments that preserve internal structures. The flamingo mounds consist of a dense, packed oval-shaped core, a surrounding 'body' of packed sediment, and an external layer with a ped-like texture of clumped mud. The nests may contain open holes from roots or feather shafts incorporated into the nest, and (or) burrows produced once the nests are abandoned. In areas with high densities of flamingos, lake margin sediments may be preferentially compacted, particularly at breeding sites, and become resistant to subaerial erosion and the effects of transgressive ravinement on time scales ranging from seasons to tens of thousands of years. The relatively well-compacted nest mounds and associated sediments also contribute to the stability of delta distributary channels during regressive-transgressive cycles, and can lead to the minor channelization of unconfined flows where currents are diverted around nest mounds. Pleistocene exhumed surfaces of relatively well-indurated lake margin sediments at Lake Bogoria and Lake Magadi that are interpreted as combined regressive and transgressive surfaces (flooding surface/sequence boundary) preserve evidence of flamingo activities, and are overlain by younger, porous lacustrine

Clay minerals behaviour in thin sandy clay-rich lacustrine turbidites (Lake Hazar, Turkey)

NASA Astrophysics Data System (ADS)

El Ouahabi, Meriam; Hubert-Ferrari, Aurelia; Lamair, Laura; Hage, Sophie

2017-04-01

Turbidites have been extensively studied in many different areas using cores or outcrop, which represent only an integrated snapshot of a dynamic evolving flow. Laboratory experiments provide the missing relationships between the flow characteristics and their deposits. In particular, flume experiments emphasize that the presence of clay plays a key role in turbidity current dynamics. Clay fraction, in small amount, provides cohesive strength to sediment mixtures and can damp turbulence. However, the degree of flocculation is dependent on factors such as the amount and size of clay particles, the surface of clay particles, chemistry and pH conditions in which the clay particles are dispersed. The present study focuses on thin clayey sand turbidites found in Lake Hazar (Turkey) occurring in stacked thin beds. Depositional processes and sources have been previously studied and three types were deciphered, including laminar flows dominated by cohesion, transitional, and turbulence flow regimes (Hage et al., in revision). For the purpose of determine the clay behavior in the three flow regimes, clay mineralogical, geochemical measurements on the cores allow characterising the turbidites. SEM observations provide further information regarding the morphology of clay minerals and other clasts. The study is particularly relevant given the highly alkaline and saline water of the Hazar Lake. Clay minerals in Hazar Lake sediments include kaolinite (1:1-type), illite and chlorite (2:1-type). Hazar lake water is alkaline having pH around 9.3, in such alkaline environment, a cation-exchange reaction takes place. Furthermore, in saline water (16‰), salts can act as a shield and decrease the repulsive forces between clay particle surfaces. So, pH and salt content jointly impact the behaviour of clays differently. Since the Al-faces of clay structures have a negative charge in basic solutions. At high pH, all kaolinite surfaces become negative-charged, and then kaolinite

Late Holocene monsoon climate as evidenced by proxy records from a lacustrine sediment sequence in western Guangdong, South China

NASA Astrophysics Data System (ADS)

Zhong, Wei; Cao, jiayuan; Xue, Jibin; Ouyang, Jun; Tang, Xiaohong; Yin, Huanling; Liao, Congyun; Long, Kun

2014-02-01

The study of a 300-cm-thick exposed lacustrine sediment section in the Hedong village in Zhaoqing area which is located in sub-tropical west Guangdong Province in South China, demonstrates that the lacustrine sedimentary sequence possibly contains evidence for exploring variation of Asian monsoon climate. Multi-proxy records, including the humification intensity, total organic carbon, and grain size fractions, reveal a general trend towards dry and cold conditions in the late Holocene that this is because of a decrease in solar insolation on an orbital scale. Three intensified Asian summer monsoon (ASM) intervals (˜3300-3000 cal yr BP, ˜2600-1600 cal yr BP, and ˜900-600 cal yr BP), and three weakened ASM intervals (˜4000-3300 cal yr BP, ˜3000-2600 cal yr BP, and ˜1600-900 cal yr BP) are identified. Our humification record (HDcal) shows a good correlation on multi-centennial scale with the tree ring Δ14C record, a proxy of solar activity. A spectral analysis of HDcal reveals four significant cycles, i.e., ˜1250 yr, 300 yr, 110 yr, and 70 yr, and most of these cycles are related to the solar activity. Our findings indicate that solar output and oceanic-atmospheric circulation probably have influenced the late Holocene climate variability in the study region.

[caCORE: core architecture of bioinformation on cancer research in America].

PubMed

Gao, Qin; Zhang, Yan-lei; Xie, Zhi-yun; Zhang, Qi-peng; Hu, Zhang-zhi

2006-04-18

A critical factor in the advancement of biomedical research is the ease with which data can be integrated, redistributed and analyzed both within and across domains. This paper summarizes the Biomedical Information Core Infrastructure built by National Cancer Institute Center for Bioinformatics in America (NCICB). The main product from the Core Infrastructure is caCORE--cancer Common Ontologic Reference Environment, which is the infrastructure backbone supporting data management and application development at NCICB. The paper explains the structure and function of caCORE: (1) Enterprise Vocabulary Services (EVS). They provide controlled vocabulary, dictionary and thesaurus services, and EVS produces the NCI Thesaurus and the NCI Metathesaurus; (2) The Cancer Data Standards Repository (caDSR). It provides a metadata registry for common data elements. (3) Cancer Bioinformatics Infrastructure Objects (caBIO). They provide Java, Simple Object Access Protocol and HTTP-XML application programming interfaces. The vision for caCORE is to provide a common data management framework that will support the consistency, clarity, and comparability of biomedical research data and information. In addition to providing facilities for data management and redistribution, caCORE helps solve problems of data integration. All NCICB-developed caCORE components are distributed under open-source licenses that support unrestricted usage by both non-profit and commercial entities, and caCORE has laid the foundation for a number of scientific and clinical applications. Based on it, the paper expounds caCORE-base applications simply in several NCI projects, of which one is CMAP (Cancer Molecular Analysis Project), and the other is caBIG (Cancer Biomedical Informatics Grid). In the end, the paper also gives good prospects of caCORE, and while caCORE was born out of the needs of the cancer research community, it is intended to serve as a general resource. Cancer research has historically

Fluvial/lacustrine diagenesis: Significance for hydrocarbon production and entrapment in the carboniferous Albert Fm, Moncton basin, NB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noble, J.P.A.; Chowdhury, A.H.; Yu, H.

1996-12-31

The Carboniferous Horton Group Albert Formation sediments include lacustrine source-rock oil shales and fluvial porous reservoir sandstones. The petrography, stable isotopes, fluid inclusions, cathodoluminescence and mirror/trace element chemistry of these sandstones are used to establish the diagenetic history and controlling factors. Early diagenetic calcite, quartz and albite cements with minor chlorite and kaolinite are variably present and related to depositional mineralogy and lake levels winch controlled the porewater chemistry. Antitaxial veins occurring preferentially in shales are shown, from heavy {delta}C{sup 13} values and fluid inclusions, to be related to methanogenesis in overpressured zones at shallow depths. Later burial calcite andmore » extensive albitisation are related to mineral reactions during the phase of rapid subsidence at temperatures of 80{degrees} to 150{degrees} in the deepest segment of the basin, together with significant dissolution of carbonates and feldspars related mainly to organic acids generated by organic maturation processes. Mass balance calculations indicate that not enough organic matter was present to account for all the estimated secondary porosity and some evidence suggests that reactions between kaolinite and calcite/ankerite to produce chlorite, and mixed layer illite-smectite ordering reactions, produced significant secondary porosity. Burial history reconstructions and thermal modelling of the Albert Fm. sediments using Arrhenius type maturity models and reflectance and rock-eval data suggest locally variable maturation and reservoir production related to the locally different fault tectonic histories characteristic of strike-slip lacustrine segmented basins. The Horton depositional cycle was followed by major dextral transpression with local faulting and inversion and vein cementation.« less

Fluvial/lacustrine diagenesis: Significance for hydrocarbon production and entrapment in the carboniferous Albert Fm, Moncton basin, NB

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noble, J.P.A.; Chowdhury, A.H.; Yu, H.

1996-01-01

The Carboniferous Horton Group Albert Formation sediments include lacustrine source-rock oil shales and fluvial porous reservoir sandstones. The petrography, stable isotopes, fluid inclusions, cathodoluminescence and mirror/trace element chemistry of these sandstones are used to establish the diagenetic history and controlling factors. Early diagenetic calcite, quartz and albite cements with minor chlorite and kaolinite are variably present and related to depositional mineralogy and lake levels winch controlled the porewater chemistry. Antitaxial veins occurring preferentially in shales are shown, from heavy [delta]C[sup 13] values and fluid inclusions, to be related to methanogenesis in overpressured zones at shallow depths. Later burial calcite andmore » extensive albitisation are related to mineral reactions during the phase of rapid subsidence at temperatures of 80[degrees] to 150[degrees] in the deepest segment of the basin, together with significant dissolution of carbonates and feldspars related mainly to organic acids generated by organic maturation processes. Mass balance calculations indicate that not enough organic matter was present to account for all the estimated secondary porosity and some evidence suggests that reactions between kaolinite and calcite/ankerite to produce chlorite, and mixed layer illite-smectite ordering reactions, produced significant secondary porosity. Burial history reconstructions and thermal modelling of the Albert Fm. sediments using Arrhenius type maturity models and reflectance and rock-eval data suggest locally variable maturation and reservoir production related to the locally different fault tectonic histories characteristic of strike-slip lacustrine segmented basins. The Horton depositional cycle was followed by major dextral transpression with local faulting and inversion and vein cementation.« less

In-situ monitoring of deformation of clayey and volcanic sequences in the lacustrine plain of Iztapalapa, Mexico City

NASA Astrophysics Data System (ADS)

Carreon-Freyre, D.; Cerca, M.; Barrientos, B.; Gutierrez, R.; Blancas, D.

2012-12-01

Major cities of Central Mexico with lowering of land elevation problems are located in inter-volcanic and fault bounded basins within the central Trans-Mexican Volcanic Belt (TMVB). The most representative and studied case of ground deformation is Mexico City, where the Iztapalapa Municipality presents the highest population density. This area is located over the geological contact between the "Sierra de Santa Catarina" volcanic range and a lacustrine plain. Filling of lacustrine basins includes silty and clayey sediments as well as pyroclastic deposits (coarse and fine grained) and volcanic rocks layers. We used Ground Penetrating Radar (GPR) and MASW prospection to evaluate contrasts in the physical properties of fine grained soils and identify geometry of the deformational features and implemented a mechanical system for in situ monitoring in fractured sites. Deformational features in this basin reflect an interplay between the geological history (depositional conditions), load history, seismic activity, and faulting. Plastic mechanical behaviour predominates in these clayey sediments and differential deformation locally triggers brittle fracturing and/or subsidence of the surface. In this work we present the results of monitoring and characterization of ground deformation and fracturing in different sequences, our results show a dynamic interplay between the mechanisms of ground fracturing and the stress history of sedimentary sequences. Relating the mechanical behaviour of the studied sequences with variations of physical and geological properties should be taken into account to estimate land level lowering and risk of fracturing for urban development planning.

Earthquake-induced soft-sediment deformation structures in Late Pleistocene lacustrine deposits of Issyk-Kul lake (Kyrgyzstan)

NASA Astrophysics Data System (ADS)

Gladkov, A. S.; Lobova, E. U.; Deev, E. V.; Korzhenkov, A. M.; Mazeika, J. V.; Abdieva, S. V.; Rogozhin, E. A.; Rodkin, M. V.; Fortuna, A. B.; Charimov, T. A.; Yudakhin, A. S.

2016-10-01

This paper discusses the composition and distribution of soft-sediment deformation structures induced by liquefaction in Late Pleistocene lacustrine terrace deposits on the southern shore of Issyk-Kul Lake in the northern Tien Shan mountains of Kyrgyzstan. The section contains seven deformed beds grouped in two intervals. Five deformed beds in the upper interval contain load structures (load casts and flame structures), convolute lamination, ball-and-pillow structures, folds and slumps. Deformation patterns indicate that a seismic trigger generated a multiple slump on a gentle slope. The dating of overlying subaerial deposits suggests correlation between the deformation features and strong earthquakes in the Late Pleistocene.

Geology and radiometric dating of Quaternary monogenetic volcanism in the western Zacapu lacustrine basin (Michoacán, México): implications for archeology and future hazard evaluations

NASA Astrophysics Data System (ADS)

Reyes-Guzmán, Nanci; Siebe, Claus; Chevrel, Magdalena Oryaëlle; Guilbaud, Marie-Noëlle; Salinas, Sergio; Layer, Paul

2018-02-01

The Zacapu lacustrine basin is located in the north-central part of the Michoacán-Guanajuato volcanic field (MGVF), which constitutes the west-central segment of the Trans-Mexican Volcanic Belt. Geological mapping of a 395 km2 quadrangle encompassing the western margin of the basin, 40Ar/39Ar and 14C radiometric dating, whole-rock chemical and petrographic analyses of volcanic products provide information on the stratigraphy, erupted volumes, age, and composition of the volcanoes. Although volcanism in the MGVF initiated since at least 5 Ma ago, rocks in the western Zacapu lacustrine basin are all younger than 2.1 Ma. A total of 47 volcanoes were identified and include 19 viscous lava flows ( 40 vol.%), 17 scoria cones with associated lava flows ( 36 vol.%), seven lava shields ( 15 vol.%), three domes ( 6 vol.%), and one maar ( 2 vol.%). Erupted products are dominantly andesites with 42 km3 ( 86 vol.%) followed by 4 km3 of dacite ( 8 vol.%), 1.4 km3 of basaltic trachy-andesite ( 3 vol.%), 1 km3 of basaltic andesite ( 2 vol.%), and 0.14 km3 of rhyolite ( 0.3 vol.%). Eruptive centers are commonly aligned ENE-WSW following the direction of the regional Cuitzeo Fault System. Over time, the high frequency of eruptions and consequent accumulation of lavas and pyroclastic materials pushed the lake's shore stepwise toward the southeast. Eruptions appear to have clustered through time. One cluster occurred during the Late Pleistocene between 27,000 and 21,300 BC when four volcanoes erupted. A second cluster formed during the Late Holocene, between 1500 BC and AD 900, when four closely spaced monogenetic vents erupted forming thick viscous `a'a to blocky flows on the margin of the lacustrine flats. For still poorly understood reasons, these apparently inhospitable lava flows were attractive to human settlement and eventually became one of the most densely populated heartlands of the pre-Hispanic Tarascan civilization. With an average eruption recurrence interval of 900

Paleotopographic control of landslides in lacustrine deposits (Trièves plateau, French western Alps)

NASA Astrophysics Data System (ADS)

Bièvre, Grégory; Kniess, Ulrich; Jongmans, Denis; Pathier, Erwan; Schwartz, Stéphane; van Westen, Cees J.; Villemin, Thierry; Zumbo, Vilma

2011-01-01

Paleotopography in Quaternary sedimentary environments can be an important factor that controls landslide movement. This study investigates the relation between paleotopography and landslide activity in two adjacent landslides in glaciolacustrine sediments located in the Trièves area (French western Alps). Although both are in slopes underlain by the same lacustrine deposits, the Avignonet and Harmalière landslides exhibit major differences in morphology and displacement rates. Through a combination of geological mapping, airborne light detection and ranging (LiDAR) data, aerial photographs, global positioning system (GPS), and seismic noise measurements, a three-dimensional impression was made of both landslides. The analysis reveals that the difference in kinematics between the two mass movements can be traced back to at least 50 years ago. The results show that the Harmalière slide, which failed catastrophically in 1981, is still much more active than the Avignonet landslide. The fear was that the Avignonet landslide might develop in a similar catastrophic manner, threatening a number of houses constructed on the landslide. A geophysical survey based on ambient noise measurements allowed us to map the base of the lacustrine clays, and the results indicate the presence of a N-S ridge of hard sediments (Jurassic bedrock and/or compact alluvial layers) on the eastern side of the Avignonet landslide. This ridge disappears when approaching the Harmalière landslide and makes a place to what can be interpreted as a NW-SE oriented paleovalley of the river Drac. We proposed that the ridge acts as a buttress that could mechanically prevent the Avignonet landslide from evolving as fast as the Harmalière. Furthermore, the NW-SE paleovalley located under the Harmalière landslide corresponds to the motion direction of the slide. Therefore, the different behaviour of the two landslides is partly controlled by the paleotopographic setting of Lake Trièves during the last

Hydrological responses of the Chihuahua Desert of Mexico to possible Heinrich Stadials: A study inferred from geochemistry and stable isotopes of lacustrine sediments

NASA Astrophysics Data System (ADS)

Quiroz-Jiménez, J. D.; Roy, P. D.; Lozano-SantaCruz, R.; López Balbiaux, N.; Girón-García, P.

2016-12-01

The Heinrich Stadials (H6-H1) were cooler intervals of different duration characterized by massive discharge of icebergs from the Laurentide Ice Sheet mainly through the Hudson Straight into the Atlantic Ocean. In this paper, we present a proxy record to infer hydrological responses of the Chihuahua Desert of Mexico to all the Heinrich Stadials (HS) from element ratios, CO3 abundance, and oxygen and carbon isotope compositions of lacustrine calcite of the sediments deposited between depths of 560-78 cm ( 66-8 ka) of a new core collected from the Santiaguillo Basin. Sediments deposited during different HS were identified by radiocarbon dating up to 27.3 ka, extrapolation of an average sediment rate and tuning the CO3 abundance record with insolation in rest of the sequence, and oxygen isotope composition of authigenic CO3. Proxies suggest that hydroclimate of the Chihuahua Desert of Mexico responded differently to different HS. The overall runoff and hence precipitation remained below average during H6, H4, H2 and H1. Both of them were above average during H5 and H3. Similarly, runoff during H4 showed the least variability and it was the most variable during H5. Except for H2, negative excursions in δ18O values suggest cooler conditions during all other HS. In general, dissolved HCO3- was mainly sourced from the atmospheric CO2 during arid intervals. Both the lake productivity and atmospheric CO2 influenced the carbon isotope composition of dissolved HCO3- during humid intervals. During the H2, δ13C values indicate dominant influence of lacustrine productivity. Similar to Chihuahua Desert of Mexico, speleothem records from Fort Stanton and Cave of the Bells (Asmerom et al., 2010; Wagner et al., 2010) showed that hydroclimate of southwest USA also experienced millennial-scale variability and some intervals were more homogeneous compared to others. We did not observe concurrency in proxy records of the Chihuahua Desert of Mexico and southwest USA. Instead, we

Pricing the Services of Scientific Cores. Part I: Charging Subsidized and Unsubsidized Users.

ERIC Educational Resources Information Center

Fife, Jerry; Forrester, Robert

2002-01-01

Explaining that scientific cores at research institutions support shared resources and facilities, discusses devising a method of charging users for core services and controlling and managing the rates. Proposes the concept of program-based management to cover sources of core support that are funding similar work. (EV)

Lead Coolant Test Facility Systems Design, Thermal Hydraulic Analysis and Cost Estimate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soli Khericha; Edwin Harvego; John Svoboda

2012-01-01

The Idaho National Laboratory prepared a preliminary technical and functional requirements (T&FR), thermal hydraulic design and cost estimate for a lead coolant test facility. The purpose of this small scale facility is to simulate lead coolant fast reactor (LFR) coolant flow in an open lattice geometry core using seven electrical rods and liquid lead or lead-bismuth eutectic coolant. Based on review of current world lead or lead-bismuth test facilities and research needs listed in the Generation IV Roadmap, five broad areas of requirements were identified as listed: (1) Develop and Demonstrate Feasibility of Submerged Heat Exchanger; (2) Develop and Demonstratemore » Open-lattice Flow in Electrically Heated Core; (3) Develop and Demonstrate Chemistry Control; (4) Demonstrate Safe Operation; and (5) Provision for Future Testing. This paper discusses the preliminary design of systems, thermal hydraulic analysis, and simplified cost estimate. The facility thermal hydraulic design is based on the maximum simulated core power using seven electrical heater rods of 420 kW; average linear heat generation rate of 300 W/cm. The core inlet temperature for liquid lead or Pb/Bi eutectic is 4200 C. The design includes approximately seventy-five data measurements such as pressure, temperature, and flow rates. The preliminary estimated cost of construction of the facility is $3.7M (in 2006 $). It is also estimated that the facility will require two years to be constructed and ready for operation.« less

Nanda-gikendaasowin Naawij Gaa-izhiwebakin Manoomini-zaaga'iganiing: Core-based research by Native students on wild rice lakes in northern Minnesota

NASA Astrophysics Data System (ADS)

Myrbo, A.; Howes, T.; Defoe, R.; Dalbotten, D. M.; Pellerin, H.; McEathron, M.; Ito, E.

2011-12-01

Little is known about how local and global environmental changes affect the habitat of wild rice (manoomin in Ojibwe; Zizania sp.). Using transects of sediment cores from wild rice lakes on the Fond du Lac Band of Lake Superior Chippewa Reservation (FDL) in Minnesota, undergraduate student researchers are working to reconstruct the lakes' ecological history in order to better manage future change. Reservation Resource Management personnel and University science mentors work together to develop research questions and mentor small groups of college-age students during short (two-week) and long (ten-week) summer internships. Cores are collected during the winter from the frozen lake surface with "Lake Teams" of mainly Native junior high and high school students attending weekend science camps, who also visit LacCore (the National Lacustrine Core Facility) in Minneapolis to conduct initial core description and basic analyses. At the same time as the Fond du Lac Band gains information about the long-term history and variability of the Reservation's lakes, young Native people are exposed to primary research, natural resources management and academia as occupations, and scientists as people. Scientific results, as well as the results of program evaluation, show clearly that this approach has so far been successful and eye-opening for both students and mentors. Lead-210 dated records of the past ~150 years cover the period of European settlement, logging, and the massive ditching of FDL lakes to convert wetlands to agricultural land. Phytolith, pollen, plant macrofossil, and diatom studies by interns, as well as sediment composition and mass accumulation rate data, show anthropogenic lake level and vegetation fluctuations associated with these activities. Earlier in the record (~10,000 years to ~100 years before present), the natural and slow processes of lake infilling and encroachment of shallow-water vegetation are the dominant processes controlling the ecology of the

Tulelake, California: The last 3 million years

USGS Publications Warehouse

Adam, D.P.; Sarna-Wojcicki, A. M.; Rieck, Hugh J.; Bradbury, J.P.; Dean, W.E.; Forester, R.M.

1989-01-01

The Tulelake basin, formed by east-west extension and faulting during the past several million years, contains at least 550 m of lacustrine sediment. Interdisciplinary studies of a 334 m-long cored section from the town of Tulelake, California, near the center of the basin, document a 3-m.y. record of environmental changes. The core consists of a thick sequence of diatomaceous clayey, silty, and marly lacustrine sediments interbedded with numerous tephra layers. Paleomagnetic study puts the base of the core at about 3.0 Ma. Twelve widespread silicic tephra units provide correlations with other areas and complement age control provided by magnetostratigraphy; mafic and silicic tephra units erupted from local sources are also common in the core. Widespread tephra units include the Llao Rock pumice (=Tsoyawata, 7 ka), the Trego Hot Springs Bed (23 ka), and the Rockland (0.40 Ma), Lava Creek (0.62 Ma), and Rio Dell (1.5 Ma) ash beds, as well as several ash beds also found at Summer Lake, Oregon, and an ash bed originally recognized in DSDP hole 173 in the northeastern Pacific. Several tephra layers found in the core also occur in lacustrine beds exposed around the margins of the basin and elsewhere in the ancestral lacustrine system. Diatoms are present throughout the section. Pollen is present in most of the section, but some barren zones are found in the interval between 50 and 140 m; the greatest change in behavior of the pollen record takes place just above the top of the Olduvai Normal-Polarity Subchronozone. Ostracodes are present only in high-carbonate (>10% CaCO3) intervals. Evolutionary changes are found in the diatom and ostracode records. Bulk geochemical analyses show significant changes in elemental composition of the sediment through time. ?? 1989.

Facile preparation of polymer microspheres and fibers with a hollow core and porous shell for oil adsorption and oil/water separation

NASA Astrophysics Data System (ADS)

Gao, Jiefeng; Song, Xin; Huang, Xuewu; Wang, Ling; Li, Bei; Xue, Huaiguo

2018-05-01

Non-solvent assisted electrospinning was proposed for fabricating Polymethylmethacrylate (PMMA) microspheres and fibers with a hollow core and porous shell, which could be used for oil adsorption and oil/water separation. Propanediol was chosen as the non-solvent because of its high surface tension and viscosity as well as large phase separation tendency with polymer, which was beneficial to the formation of both the hollow core and porous shell during the electrospinning. With the increase of the polymer solution concentration, the microsphere gradually evolved to the bead-on-string geometry and finally to a continuous fiber form, indicating the transition from electro-spraying to electrospinning. The hollow core and dense surface pores enhanced the hydrophobicity, oleophilicity, permeability, and specific surface area of the fibers, and hence imparted the fibrous mat a high oil adsorption capacity. When the porous hollow microspheres were electro-sprayed onto the stainless steel mesh followed by the PDMS modification, the modified mesh became super-hydrophobic and super-oleophilic with the contact angle of 153° and sliding angle of 4°. The as-prepared mesh showed rapid oil/water separation with high efficiency and excellent recycling performance. The flux for separation of oil/water mixture could reach as high as 11,000 L m-2 h-1. This facile non-solvent assisted electrospinning method provides a new avenue for preparation of multifunctional porous materials which possess potential applications in large-scale oil/water separation.

Pricing the Services of Scientific Cores. Part II: Charging Outside Users.

ERIC Educational Resources Information Center

Fife, Jerry; Forrester, Robert

2002-01-01

Explaining that scientific cores at research institutions support shared resources and facilities, considers pricing of services to users from outside the institution. Proposes a method of allocating charges from the cores to projects with multiple funding sources through program-based management. Describes aspects of an example program: price of…

Nuclear thermal propulsion test facility requirements and development strategy

NASA Technical Reports Server (NTRS)

Allen, George C.; Warren, John; Clark, J. S.

1991-01-01

The Nuclear Thermal Propulsion (NTP) subpanel of the Space Nuclear Propulsion Test Facilities Panel evaluated facility requirements and strategies for nuclear thermal propulsion systems development. High pressure, solid core concepts were considered as the baseline for the evaluation, with low pressure concepts an alternative. The work of the NTP subpanel revealed that a wealth of facilities already exists to support NTP development, and that only a few new facilities must be constructed. Some modifications to existing facilities will be required. Present funding emphasis should be on long-lead-time items for the major new ground test facility complex and on facilities supporting nuclear fuel development, hot hydrogen flow test facilities, and low power critical facilities.

Empirical quantification of lacustrine groundwater discharge - different methods and their limitations

NASA Astrophysics Data System (ADS)

Meinikmann, K.; Nützmann, G.; Lewandowski, J.

2015-03-01

Groundwater discharge into lakes (lacustrine groundwater discharge, LGD) can be an important driver of lake eutrophication. Its quantification is difficult for several reasons, and thus often neglected in water and nutrient budgets of lakes. In the present case several methods were applied to determine the expansion of the subsurface catchment, to reveal areas of main LGD and to identify the variability of LGD intensity. Size and shape of the subsurface catchment served as a prerequisite in order to calculate long-term groundwater recharge and thus the overall amount of LGD. Isotopic composition of near-shore groundwater was investigated to validate the quality of catchment delineation in near-shore areas. Heat as a natural tracer for groundwater-surface water interactions was used to find spatial variations of LGD intensity. Via an analytical solution of the heat transport equation, LGD rates were calculated from temperature profiles of the lake bed. The method has some uncertainties, as can be found from the results of two measurement campaigns in different years. The present study reveals that a combination of several different methods is required for a reliable identification and quantification of LGD and groundwater-borne nutrient loads.

Imaging of High-Z doped, Imploded Capsule Cores

NASA Astrophysics Data System (ADS)

Prisbrey, Shon T.; Edwards, M. John; Suter, Larry J.

2006-10-01

The ability to correctly ascertain the shape of imploded fusion capsules is critical to be able to achieve the spherical symmetry needed to maximize the energy yield of proposed fusion experiments for the National Ignition Facility. Implosion of the capsule creates a hot, dense core. The introduction of a high-Z dopant into the gas-filled core of the capsule increases the amount of bremsstrahlung radiation produced in the core and should make the imaging of the imploded core easier. Images of the imploded core can then be analyzed to ascertain the symmetry of the implosion. We calculate that the addition of Ne gas into a deuterium gas core will increase the amount of radiation emission while preserving the surrogacy of the radiation and hydrodynamics in the indirect drive NIF hohlraum in the proposed cryogenic hohlraums. The increased emission will more easily enable measurement of asymmetries and tuning of the implosion.

Titanium dioxide@polypyrrole core-shell nanowires for all solid-state flexible supercapacitors

NASA Astrophysics Data System (ADS)

Yu, Minghao; Zeng, Yinxiang; Zhang, Chong; Lu, Xihong; Zeng, Chenghui; Yao, Chenzhong; Yang, Yangyi; Tong, Yexiang

2013-10-01

Herein, we developed a facile two-step process to synthesize TiO2@PPy core-shell nanowires (NWs) on carbon cloth and reported their improved electrochemical performance for flexible supercapacitors (SCs). The fabricated solid-state SC device based on TiO2@PPy core-shell NWs not only has excellent flexibility, but also exhibits remarkable electrochemical performance.Herein, we developed a facile two-step process to synthesize TiO2@PPy core-shell nanowires (NWs) on carbon cloth and reported their improved electrochemical performance for flexible supercapacitors (SCs). The fabricated solid-state SC device based on TiO2@PPy core-shell NWs not only has excellent flexibility, but also exhibits remarkable electrochemical performance. Electronic supplementary information (ESI) available: Experimental details, XRD pattern, FT-IR absorption spectrum and CV curves of TiO2@PPy NWs, and SEM images of the PPy. See DOI: 10.1039/c3nr03578f

Space Launch System, Core Stage, Structural Test Design and Implementation

NASA Technical Reports Server (NTRS)

Shaughnessy, Ray

2017-01-01

As part of the National Aeronautics and Space Administration's (NASA) Space Launch System (SLS) Program, engineers at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama are working to design, develop and implement the SLS Core Stage structural testing. The SLS will have the capability to return humans to the Moon and beyond and its first launch is scheduled for December of 2017. The SLS Core Stage consist of five major elements; Forward Skirt, Liquid Oxygen (LOX) tank, Intertank (IT), Liquid Hydrogen (LH2) tank and the Engine Section (ES). Structural Test Articles (STA) for each of these elements are being designed and produced by Boeing at Michoud Assembly Facility located in New Orleans, La. The structural test for the Core Stage STAs (LH2, LOX, IT and ES) are to be conducted by the MSFC Test Laboratory. Additionally, the MSFC Test Laboratory manages the Structural Test Equipment (STE) design and development to support the STAs. It was decided early (April 2012) in the project life that the LH2 and LOX tank STAs would require new test stands and the Engine Section and Intertank would be tested in existing facilities. This decision impacted schedules immediately because the new facilities would require Construction of Facilities (C of F) funds that require congressional approval and long lead times. The Engine Section and Intertank structural test are to be conducted in existing facilities which will limit lead times required to support the first launch of SLS. With a SLS launch date of December, 2017 Boeing had a need date for testing to be complete by September of 2017 to support flight certification requirements. The test facilities were required to be ready by October of 2016 to support test article delivery. The race was on to get the stands ready before Test Article delivery and meet the test complete date of September 2017. This paper documents the past and current design and development phases and the supporting processes, tools, and

17 CFR 37.900 - Core Principle 9-Timely publication of trading information.

Code of Federal Regulations, 2014 CFR

2014-04-01

... publication of trading information. 37.900 Section 37.900 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION SWAP EXECUTION FACILITIES Timely Publication of Trading Information § 37.900 Core Principle 9—Timely publication of trading information. (a) In general. The swap execution facility shall...

Efficient tungsten oxide/bismuth oxyiodide core/shell photoanode for photoelectrochemical water splitting

NASA Astrophysics Data System (ADS)

Ma, Haipeng; Zhang, Jing; Liu, Zhifeng

2017-11-01

The novel WO3 nanorods (NRs)/BiOI core/shell structure composite is used as an efficient photoanode applied in photoelectrochemical (PEC) water splitting for the first time. It is synthesized via facile hydrothermal method and, successive ionic layer adsorption and reaction (SILAR) process. This facile synthesis route can achieve uniform WO3/BiOI core/shell composite nanostructures and obtain varied BiOI morphologies simultaneously. The WO3 NRs/BiOI-20 composite exhibits enhanced PEC activity compared to pristine WO3 with a photocurrent density of 0.79 mA cm-2 measured at 0.8 V vs. RHE under AM 1.5G. This excellent performance benefits from the broader absorption spectrum and suppressed electron-hole recombination. This novel core/shell composite may provide insight in developing more efficient solar driven photoelectrodes.

Deposition and deformation of fluvial-lacustrine sediments of the Upper Triassic-Lower Jurassic Whitmore Point Member, Moenave Formation, northern Arizona

NASA Astrophysics Data System (ADS)

Tanner, Lawrence H.; Lucas, Spencer G.

2010-01-01

The stratigraphic section of the Upper Triassic-Lower Jurassic Whitmore Point Member of the Moenave Formation at Potter Canyon, Arizona, comprises c. 26 m of gray to black shales and red mudstones interbedded with mainly sheet-like siltstones and sandstones. These strata represent deposition from suspension and sheetflow processes in shallow, perennial meromictic to ephemeral lakes, and on dry mudflats of the terminal floodout of the northward-flowing Moenave stream system. The lakes were small, as indicated by the lack of shoreline features and limited evidence for deltas. Changes in base level, likely forced by climate change, drove the variations between mudflat and perennial lacustrine conditions. Lenticular sandstones that occur across the outcrop face in the same stratigraphic interval in the lower part of the sequence represent the bedload fill of channels incised into a coarsening-upward lacustrine sequence following a fall in base level. These sandstones are distinctive for the common presence of over-steepened bedding, dewatering structures, and less commonly, folding. Deformation of these sandstones is interpreted as aseismic due to the lack of features typically associated with seismicity, such as fault-graded bedding, diapirs, brecciated fabrics and clastic dikes. Rapid deposition of the sands on a fluid-rich substrate produced a reverse density gradient that destabilized, and potentially fluidized the underlying, finer-grained sediments. This destabilization allowed synsedimentary subsidence of most of the channel sands, accompanied by longitudinal rotation and/or ductile deformation of the sand bodies.

Lacustrine turbidites as a tool for quantitative earthquake reconstruction: New evidence for a variable rupture mode in south central Chile

NASA Astrophysics Data System (ADS)

Moernaut, Jasper; Daele, Maarten Van; Heirman, Katrien; Fontijn, Karen; Strasser, Michael; Pino, Mario; Urrutia, Roberto; De Batist, Marc

2014-03-01

Understanding the long-term earthquake recurrence pattern at subduction zones requires continuous paleoseismic records with excellent temporal and spatial resolution and stable threshold conditions. South central Chilean lakes are typically characterized by laminated sediments providing a quasi-annual resolution. Our sedimentary data show that lacustrine turbidite sequences accurately reflect the historical record of large interplate earthquakes (among others the 2010 and 1960 events). Furthermore, we found that a turbidite's spatial extent and thickness are a function of the local seismic intensity and can be used for reconstructing paleo-intensities. Consequently, our multilake turbidite record aids in pinpointing magnitudes, rupture locations, and extent of past subduction earthquakes in south central Chile. Comparison of the lacustrine turbidite records with historical reports, a paleotsunami/subsidence record, and a marine megaturbidite record demonstrates that the Valdivia Segment is characterized by a variable rupture mode over the last 900 years including (i) full ruptures (Mw ~9.5: 1960, 1575, 1319 ± 9, 1127 ± 44), (ii) ruptures covering half of the Valdivia Segment (Mw ~9: 1837), and (iii) partial ruptures of much smaller coseismic slip and extent (Mw ~7.5-8: 1737, 1466 ± 4). Also, distant or smaller local earthquakes can leave a specific sedimentary imprint which may resolve subtle differences in seismic intensity values. For instance, the 2010 event at the Maule Segment produced higher seismic intensities toward southeastern localities compared to previous megathrust ruptures of similar size and extent near Concepción.

Impacts of shore expansion and catchment characteristics on lacustrine thermokarst records in permafrost lowlands, Alaska Arctic Coastal Plain

USGS Publications Warehouse

Lenz, Josefine; Jones, Benjamin M.; Wetterich, Sebastian; Tjallingii, Rik; Fritz, Michael; Arp, Christopher D.; Rudaya, Natalia; Grosse, Guido

2016-01-01

Arctic lowland landscapes have been modified by thermokarst lake processes throughout the Holocene. Thermokarst lakes form as a result of ice-rich permafrost degradation, and they may expand over time through thermal and mechanical shoreline erosion. We studied proximal and distal sedimentary records from a thermokarst lake located on the Arctic Coastal Plain of northern Alaska to reconstruct the impact of catchment dynamics and morphology on the lacustrine depositional environment and to quantify carbon accumulation in thermokarst lake sediments. Short cores were collected for analysis of pollen, sedimentological, and geochemical proxies. Radiocarbon and 210Pb/137Cs dating, as well as extrapolation of measured historic lake expansion rates, were applied to estimate a minimum lake age of ~1400 calendar years BP. The pollen record is in agreement with the young lake age as it does not include evidence of the “alder high” that occurred in the region ~4000 cal yr BP. The lake most likely initiated from a remnant pond in a drained thermokarst lake basin (DTLB) and deepened rapidly as evidenced by accumulation of laminated sediments. Increasing oxygenation of the water column as shown by higher Fe/Ti and Fe/S ratios in the sediment indicate shifts in ice regime with increasing water depth. More recently, the sediment source changed as the thermokarst lake expanded through lateral permafrost degradation, alternating from redeposited DTLB sediments, to increased amounts of sediment from eroding, older upland deposits, followed by a more balanced combination of both DTLB and upland sources. The characterizing shifts in sediment sources and depositional regimes in expanding thermokarst lakes were, therefore, archived in the thermokarst lake sedimentary record. This study also highlights the potential for Arctic lakes to recycle old carbon from thawing permafrost and thermokarst processes.

POWER-BURST FACILITY (PBF) CONCEPTUAL DESIGN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wasserman, A.A.; Johnson, S.O.; Heffner, R.E.

1963-06-21

A description is presented of the conceptual design of a high- performance, pulsed reactor called the Power Burst Facility (PBF). This reactor is designed to generate power bursts with initial asymptotic periods as short as 1 msec, producing energy releases large enough to destroy entire fuel subassemblies placed in a capsule or flow loop mounted in the reactor, all without damage to the reactor itself. It will be used primarily to evaluate the consequences and hazards of very rapid destructive accidents in reactors representing the entire range of current nuclear technology as applied to power generation, propulsion, and testing. Itmore » will also be used to carry out detailed studies of nondestructive reactivity feedback mechanisms in the shortperiod domain. The facility was designed to be sufficiently flexible to accommodate future cores of even more advanced design. The design for the first reactor core is based upon proven technology; hence, completion of the final design of this core will involve no significant development delays. Construction of the PBF is proposed to begin in September 1984, and is expected to take approximately 20 months to complete. (auth)« less

TREE Simulation Facilities, Second Edition, Revision 2

DTIC Science & Technology

1979-01-01

included radiation effects on propellants , ordnance, electronics and chemicals, vehicle shielding, neutron radiography , dosimetry, and health physics...Special Capabilities 2.11.10.1 Radiography Facility 2.11.10.2 Flexo-Rabbit System Support Capabilities 2.11.11.1 Staff 2.11.11.2 Electronics...5,400-MW pulsing operation (experimental dosimetry values for a typical core loading of 94 fuel elements). 2-156 2-46 ACPR radiography facility

A short review of paleoenvironments for Lower Beaufort (Upper Permian) Karoo sequences from southern to central Africa: A major Gondwana Lacustrine episode

NASA Astrophysics Data System (ADS)

Yemane, K.; Kelts, K.

This paper compares Karoo deposits within the Lower Beaufort (Late Permian) time interval from southern to central Africa. Facies aspects are summarized for selected sequences and depositional environments assessed in connection with the palaeogeography. The comparison shows that thickness of Lower Beaufort sequences varies greatly; sequences are over a kilometre thick at the southern tip, but decrease drastically to the north, northwest and northeast, and is commonly absent from the western part of the subcontinent. Depositional environments are continental except for small estuarine intervals from a sequence in Tanzania. The commonest lithologies comprise mudstones, siltstones, arkoses and carbonates. In spite of the dominance of fluvial facies, the records preserved by intervals of lacustrine sequences suggest that large lakes were major features of the palaeogeography, and that lacustrine environments may have been dominant deposition environments. The Lower Beaufort landscape is generally interpreted as an expansive cratonic lowland with meandering rivers and streams crossing vast floodplains, which were indented by concomitant shallow lakes of various sizes. The lakes from the Karoo tectono-sedimentary terrain were often ephemeral and closely linked with fluvial processes, but large, anoxic lakers are also documented. On the other hand, giant, freshwater lakes, covered large areas of the Zambezian tectono-sedimentary terrain and may have been locally connected. Evidence from abundant freshwater fossil assemblages, particularly from the Zambezian tectono-sedimentary terrain suggest that in spite of the generally semi-arid global climate of the Upper Permian, seasonal precipitation (monsoonal?) supplied enough moisture to sustain large perennial lakes. Because of the unique nature of the Permian cotinental configuration and palaeogeography, however, modern analogues of large systems are lacking. The general lithological and palaeontological correlability of

Geochemical control on the reduction of U(VI) to mononuclear U(IV) species in lacustrine sediments

NASA Astrophysics Data System (ADS)

Stetten, L.; Mangeret, A.; Brest, J.; Seder-Colomina, M.; Le Pape, P.; Ikogou, M.; Zeyen, N.; Thouvenot, A.; Julien, A.; Alcalde, G.; Reyss, J. L.; Bombled, B.; Rabouille, C.; Olivi, L.; Proux, O.; Cazala, C.; Morin, G.

2018-02-01

Contaminated systems in which uranium (U) concentrations slightly exceed the geochemical background are of particular interest to identify natural processes governing U trapping and accumulation in Earth's surface environments. For this purpose, we examined the role of early diagenesis on the evolution of U speciation and mobility in sediments from an artificial lake located downstream from a former mining site. Sediment and pore water chemistry together with U and Fe solid state speciation were analyzed in sediment cores sampled down to 50 cm depth at four locations in the lake. These organic-rich sediments (∼12% organic C) exhibited U concentrations in the 40-80 mg kg-1 range. The sediment columns were anoxic 2-3 mm below the sediment-water interface and pore waters pH was circumneutral. Pore water chemistry profiles showed that organic carbon mineralization was associated with Fe and Mn reduction and was correlated with a decrease in dissolved U concentration with depth. Immobilization of U in the sediment was correlated with the reduction of U(VI) to U(IV) at depth, as shown by U LIII-edge XANES spectroscopic analysis. XANES and EXAFS spectroscopy at the Fe K-edge showed the reduction of structural Fe(III) to Fe(II) in phyllosilicate minerals with depth, coincident with U(VI) to U(IV) reduction. Thermodynamic modeling suggests that Fe(II) could act as a major reducing agent for U(VI) during early diagenesis of these sediments, leading to complete U reduction below ∼30 cm depth. Shell-by-shell and Cauchy-Wavelet analysis of U LIII-EXAFS spectra indicates that U(VI) and U(IV) are mainly present as mononuclear species bound to C, P or Si ligands. Chemical extractions confirmed that ∼60-80% of U was present as non-crystalline species, which emphasizes that such species should be considered when evaluating the fate of U in lacustrine environments and the efficiency of sediment remediation strategies.

St. Petersburg Coastal and Marine Science Center's Core Archive Portal

USGS Publications Warehouse

Reich, Chris; Streubert, Matt; Dwyer, Brendan; Godbout, Meg; Muslic, Adis; Umberger, Dan

2012-01-01

This Web site contains information on rock cores archived at the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center (SPCMSC). Archived cores consist of 3- to 4-inch-diameter coral cores, 1- to 2-inch-diameter rock cores, and a few unlabeled loose coral and rock samples. This document - and specifically the archive Web site portal - is intended to be a 'living' document that will be updated continually as additional cores are collected and archived. This document may also contain future references and links to a catalog of sediment cores. Sediment cores will include vibracores, pushcores, and other loose sediment samples collected for research purposes. This document will: (1) serve as a database for locating core material currently archived at the USGS SPCMSC facility; (2) provide a protocol for entry of new core material into the archive system; and, (3) set the procedures necessary for checking out core material for scientific purposes. Core material may be loaned to other governmental agencies, academia, or non-governmental organizations at the discretion of the USGS SPCMSC curator.

Geophysical imaging of the lacustrine sediments deposited in the La Calderilla Volcanic Caldera (Gran Canaria Island, Spain) for paleoclimate research

NASA Astrophysics Data System (ADS)

Himi, Mahjoub; Rodríguez-González, Alejandro; Criado, Constantino; Tapias, Josefina C.; Ravazzi, Cesare; Pérez-Torrado, Francisco; Casas, Albert

2016-04-01

The discovery of well-preserved maar structures is important not only for studying the eruptive activity and formation of volcanoes, but also for paleoclimate research, since laminated maar lake sediments may contain very detailed archives of climate and environmental history. Maars are a singular type of volcanic structure generated by explosive phreatomagmatic eruptions as a result of interaction between rising magma and groundwater. This kind of structures are characterised by circular craters, often filled with water and/or lacustrine sediments and surrounded by a ring of pyroclastic deposits.Recently a borehole was drilled at the bottom of La Calderilla volcanic complex which penetrated about 8.7 m in its sedimentary sequence and paleobotanical study has supplied the first evidence of paleoenvironmental evolution during the Holocene on the Gran Canaria Island. This survey, however, did not penetrate into the substrate because the total thickness of the sedimentary fill was unknown. Since the age of formation of La Calderilla volcanic complex based on K/Ar dating is about 85,000 years (Upper Pleistocene), the possibility of its sedimentary fill extends beyond of the Holocene is extremely attractive, since, for example, there are few paleoenvironmental data regarding how much the last glaciation that affected the Canary Islands. In these circumstances, the knowledge of the total thickness of the lacustrine sediments is crucial to design a deeper borehole in the next future. Therefore, the subsurface characterisation provided by geophysics is essential for determining thickness and geometry of the sedimentary filling. Multielectrode ERT method was used to obtain five 2-D resistivity cross-sections into La Calderilla volcanic caldera. An Iris Syscal Pro resistivity system with 48 electrodes connected to a 94 m long cable (2m electrode spacing) in Wenner-Schlumberger configuration for an investigation depth of about 20 m. Data quality (q <2 %).was assessed by

Facile Synthesis of Core/Shell-like NiCo2O4-Decorated MWCNTs and its Excellent Electrocatalytic Activity for Methanol Oxidation

PubMed Central

Ko, Tae-Hoon; Devarayan, Kesavan; Seo, Min-Kang; Kim, Hak-Yong; Kim, Byoung-Suhk

2016-01-01

The design and development of an economic and highly active non-precious electrocatalyst for methanol electrooxidation is challenging due to expensiveness of the precursors as well as processes and non-ecofriendliness. In this study, a facile preparation of core-shell-like NiCo2O4 decorated MWCNTs based on a dry synthesis technique was proposed. The synthesized NiCo2O4/MWCNTs were characterized by infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and selected area energy dispersive spectrum. The bimetal oxide nanoparticles with an average size of 6 ± 2 nm were homogeneously distributed onto the surface of the MWCNTs to form a core-shell-like nanostructure. The NiCo2O4/MWCNTs exhibited excellent electrocatalytic activity for the oxidation of methanol in an alkaline solution. The NiCo2O4/MWCNTs exhibited remarkably higher current density of 327 mA/cm2 and a lower onset potential of 0.128 V in 1.0 M KOH with as high as 5.0 M methanol. The impressive electrocatalytic activity of the NiCo2O4/MWCNTs is promising for development of direct methanol fuel cell based on non-Pt catalysts. PMID:26828633

Space Station Furnace Facility. Volume 2: Appendix 1: Contract End Item specification (CEI), part 1

NASA Technical Reports Server (NTRS)

Seabrook, Craig

1992-01-01

This specification establishes the performance, design, development, and verification requirements for the Space Station Furnace Facility (SSFF) Core. The definition of the SSFF Core and its interfaces, specifies requirements for the SSFF Core performance, specifies requirements for the SSFF Core design, and construction are presented, and the verification requirements are established.

High-resolution seismic stratigraphy of an Holocene lacustrine delta in western Lake Geneva (Switzerland)

USGS Publications Warehouse

Baster, I.; Girardclos, S.; Pugin, A.; Wildi, W.

2003-01-01

A high-resolution seismic survey was conducted in western Lake Geneva on a small delta formed by the Promenthouse, the Asse and the Boiron rivers. This dataset provides information on changes in the geometry and sedimentation patterns of this delta from Late-glacial to Present. The geometry of the deposits of the lacustrine delta has been mapped using 300-m spaced grid lines acquired with a 12 kHz Echosounder subbottom profiler. A complete three dimensional image of the sediment architecture was reconstructed through seismic stratigraphic analysis. Six different delta lobes have been recognized in the prodelta area. Depositional centers and lateral extension of the delta have changed through time, indicating migration and fluctuation of river input as well as changes in lake currents and wind regime from the time of glacier retreat to the Present. The delta slope is characterized by a high instability causing stumps developing and by the accumulation of biogenic gas that prevents seismic penetration.

17 CFR 37.400 - Core Principle 4-Monitoring of trading and trade processing.

Code of Federal Regulations, 2014 CFR

2014-04-01

... trading and trade processing. 37.400 Section 37.400 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION SWAP EXECUTION FACILITIES Monitoring of Trading and Trade Processing § 37.400 Core Principle 4—Monitoring of trading and trade processing. The swap execution facility shall: (a) Establish and...

The Current Status of the Space Station Biological Research Project: a Core Facility Enabling Multi-Generational Studies under Slectable Gravity Levels

NASA Astrophysics Data System (ADS)

Santos, O.

2002-01-01

The Space Station Biological Research Project (SSBRP) has developed a new plan which greatly reduces the development costs required to complete the facility. This new plan retains core capabilities while allowing for future growth. The most important piece of equipment required for quality biological research, the 2.5 meter diameter centrifuge capable of accommodating research specimen habitats at simulated gravity levels ranging from microgravity to 2.0 g, is being developed by NASDA, the Japanese space agency, for the SSBRP. This is scheduled for flight to the ISS in 2007. The project is also developing a multi-purpose incubator, an automated cell culture unit, and two microgravity habitat holding racks, currently scheduled for launch in 2005. In addition the Canadian Space Agency is developing for the project an insect habitat, which houses Drosophila melanogaster, and provides an internal centrifuge for 1 g controls. NASDA is also developing for the project a glovebox for the contained manipulation and analysis of biological specimens, scheduled for launch in 2006. This core facility will allow for experimentation on small plants (Arabidopsis species), nematode worms (C. elegans), fruit flies (Drosophila melanogaster), and a variety of microorganisms, bacteria, yeast, and mammalian cells. We propose a plan for early utilization which focuses on surveys of changes in gene expression and protein structure due to the space flight environment. In the future, the project is looking to continue development of a rodent habitat and a plant habitat that can be accommodated on the 2.5 meter centrifuge. By utilizing the early phases of the ISS to broadly answer what changes occur at the genetic and protein level of cells and organisms exposed to the ISS low earth orbit environment, we can generate interest for future experiments when the ISS capabilities allow for direct manipulation and intervention of experiments. The ISS continues to hold promise for high quality, long

Spatiotemporal Patterns of Hydrological Changes During the Younger Dryas Onset from Decadally-Resolved Lacustrine Biomarker Records: a W-E European Transect

NASA Astrophysics Data System (ADS)

Collins, J.; Aichner, B.; Engels, S.; Lane, C.; Maas, D.; Neugebauer, I.; Ott, F.; Slowinski, M. M.; Wulf, S.; Plessen, B.; Brauer, A.; Sachse, D.

2016-12-01

Future projections of European hydroclimate change remain uncertain, highlighting the need for an improved understanding of past abrupt European hydroclimate change, particularly in terms of identifying vulnerable regions. However, most existing continental paleohydrological records are not of sufficiently high resolution and/or sufficiently well dated for the assessment of leads and lags across the European continent and with the Greenland ice cores. To better understand mechanisms and feedbacks of hydrological changes during the last major abrupt climate change, the Younger Dryas (YD) cold period, we measured biomarker hydrogen isotopes (δD values) from terrestrial and aquatic sources on four high-resolution lacustrine sediment profiles. The sites span a 900km W-E transect from western Germany to eastern Poland and include: Meerfelder Maar, western Germany [MFM]; Hämelsee, northern-central Germany [HÄM]; Rehwiese, eastern Germany [RW]; Trzechowskie, central Poland [TRZ]. These sediments are annually laminated and contain common tephra layers, permitting a direct comparison of each site and allowing the identification of leads and lags in the response of the hydrological cycle to YD cooling on decadal timescales. We observed a decrease in biomarker δD values, likely reflecting cooling, that coincided with the onset of Greenland Stadial 1 in the NGRIP ice core at 12,846 years BP in the western European sites, with a progressive lag of several decades in the more easterly sites. Furthermore, we observed that the onset of aridification at all four sites occurred later but at roughly at the same time, coinciding with the biostratigraphically-defined onset of the YD at 12,679. A decrease in the magnitude of changes in biomarker δD values and aridification from W to E suggests a less strong aridification in eastern Europe. Our results suggest that hydrological changes at the onset of the YD were not uniform and were strongest and most abrupt in western Europe

From core to coax: extending core RF modelling to include SOL, Antenna, and PFC

NASA Astrophysics Data System (ADS)

Shiraiwa, Syun'ichi

2017-10-01

A new technique for the calculation of RF waves in toroidal geometry enables the simultaneous incorporation of antenna geometry, plasma facing components (PFCs), the scrape off-layer (SOL), and core propagation. Traditionally, core RF wave propagation and antenna coupling has been calculated separately both using rather simplified SOL plasmas. The new approach, instead, allows capturing wave propagation in the SOL and its interactions with non-conforming PFCs permitting self-consistent calculation of core absorption and edge power loss, as well as investigating far and near field impurity generation from RF sheaths and a breakdown issue from antenna electric fields. Our approach combines the field solutions obtained from a core spectral code with a hot plasma dielectric and an edge FEM code using a cold plasma approximation via surface admittance-like matrix. Our approach was verified using the TORIC core ICRF spectral code and the commercial COMSOL FEM package, and was extended to 3D torus using open-source scalable MFEM library. The simulation result revealed that as the core wave damping gets weaker, the wave absorption in edge could become non-negligible. Three dimensional capabilities with non axisymmetric edge are being applied to study the antenna characteristic difference between the field aligned and toroidally aligned antennas on Alcator C-Mod, as well as the surface wave excitation on NSTX-U. Work supported by the U.S. DoE, OFES, using User Facility Alcator C-Mod, DE-FC02-99ER54512 and Contract No. DE-FC02-01ER54648.

Application of core-shell-structured CdTe@SiO2 quantum dots synthesized via a facile solution method for improving latent fingerprint detection

NASA Astrophysics Data System (ADS)

Gao, Feng; Han, Jiaxing; Lv, Caifeng; Wang, Qin; Zhang, Jun; Li, Qun; Bao, Liru; Li, Xin

2012-10-01

Fingerprint detection is important in criminal investigation. This paper reports a facile powder brushing technique for improving latent fingerprint detection using core-shell-structured CdTe@SiO2 quantum dots (QDs) as fluorescent labeling marks. Core-shell-structured CdTe@SiO2 QDs are prepared via a simple solution-based approach using NH2NH2·H2O as pH adjustor and stabilizer, and their application for improving latent fingerprint detection is explored. The obtained CdTe@SiO2 QDs show spherical shapes with well-defined core-shell structures encapsulating different amounts of QDs depending on the type of the pH adjustor and stabilizer. Moreover, the fluorescence of CdTe@SiO2 QDs is largely enhanced by surface modification of the SiO2 shell. The CdTe@SiO2 QDs overcome the oxidation problem of pure CdTe QDs in air, thus affording better variability with strong adhesive ability, better resolution, and bright emission colors for practical application in latent fingerprint detection. In comparison with the conventional fluorescence powders, silver powders, and others, the effectiveness of CdTe@SiO2 QD powders for detection of latent fingerprints present on a large variety of object surfaces is greatly improved. The synthesis method for CdTe@SiO2 QDs is simple, cheap, and easy for large-scale production, and thus offers many advantages in the practical application of fingerprint detection.

Incorporation of 3H-thymidine by different prokaryotic groups in relation to temperature and nutrients in a lacustrine ecosystem.

PubMed

Boucher, Delphine; Richardot, Mathilde; Thénot, Aurélie; Debroas, Didier

2006-10-01

The incorporation of [3H-methyl] thymidine (3H-TdR) by Eubacteria, bacterial groups (alpha- and beta-Proteobacteria, Cytophaga-Flavobacter), and Archaea was measured according to temperature (7 and 17 degrees C) and nutrient levels (nitrogen, phosphorus, and carbon) in a lacustrine system (Sep, France). Short-term incubation was performed using a combination of microautoradiography and fluorescent in situ hybridization. Irrespective of the temperatures and nutrients studied, all the major phylogenetic bacterial groups assimilated 3H-TdR, and in most of the treatments studied, the proportion of beta-Proteobacteria taking up 3H-TdR was higher than those in the other bacterial groups. The proportion of Bacteria and different bacterial groups studied incorporating 3H-TdR were significantly increased, approximately 1.5-fold, by temperature except for alpha-Proteobacteria (7.6-fold). The nutrient effect was not the same for the different bacterial groups according to the temperatures studied. The proportions of alpha-Proteobacteria (at both temperatures) and Cytophaga-Flavobacter (at 7 degrees C) taking up 3H-TdR were significantly decreased and increased by adding N and P, respectively. Also, adding N, P, and C increased and decreased the percentage of beta-Proteobacteria incorporating 3H-TdR at 7 and 17 degrees C, respectively. The archaeal community showed a similar proportion of active cells (i.e., 3H-TdR) to the bacterial community, and uptake of 3H-TdR by Archaea was significantly increased (P < 0.05) by both temperature and nutrients. Thus, the assimilation of 3H-TdR by bacterial groups and Archaea in lacustrine system is significantly controlled by both temperature and nutrients.

The NASA Lewis Research Center Water Tunnel Facility

NASA Technical Reports Server (NTRS)

Wasserbauer, Charles A.

1997-01-01

A water tunnel facility specifically designed to investigate internal fluid duct flows has been built at the NASA Research Center. It is built in a modular fashion so that a variety of internal flow test hardware can be installed in the facility with minimal facility reconfiguration. The facility and test hardware interfaces are discussed along with design constraints for future test hardware. The inlet chamber flow conditioning approach is also detailed. Instrumentation and data acquisition capabilities are discussed. The incoming flow quality has been documented for about one quarter of the current facility operating range. At that range, there is some scatter in the data in the turbulent boundary layer which approaches 10 percent of the duct radius leading to a uniform core.

Core-core and core-valence correlation

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

1988-01-01

The effect of (1s) core correlation on properties and energy separations was analyzed using full configuration-interaction (FCI) calculations. The Be 1 S - 1 P, the C 3 P - 5 S and CH+ 1 Sigma + or - 1 Pi separations, and CH+ spectroscopic constants, dipole moment and 1 Sigma + - 1 Pi transition dipole moment were studied. The results of the FCI calculations are compared to those obtained using approximate methods. In addition, the generation of atomic natural orbital (ANO) basis sets, as a method for contracting a primitive basis set for both valence and core correlation, is discussed. When both core-core and core-valence correlation are included in the calculation, no suitable truncated CI approach consistently reproduces the FCI, and contraction of the basis set is very difficult. If the (nearly constant) core-core correlation is eliminated, and only the core-valence correlation is included, CASSCF/MRCI approached reproduce the FCI results and basis set contraction is significantly easier.

Titanium dioxide@polypyrrole core-shell nanowires for all solid-state flexible supercapacitors.

PubMed

Yu, Minghao; Zeng, Yinxiang; Zhang, Chong; Lu, Xihong; Zeng, Chenghui; Yao, Chenzhong; Yang, Yangyi; Tong, Yexiang

2013-11-21

Herein, we developed a facile two-step process to synthesize TiO2@PPy core-shell nanowires (NWs) on carbon cloth and reported their improved electrochemical performance for flexible supercapacitors (SCs). The fabricated solid-state SC device based on TiO2@PPy core-shell NWs not only has excellent flexibility, but also exhibits remarkable electrochemical performance.

Paleogeographic implications of Late Miocene lacustrine and nonmarine evaporite deposits in the Lake Mead region: Immediate precursors to the Colorado River

USGS Publications Warehouse

Faulds, James E.; Schreiber, Charlotte; Langenheim, Victoria; Hinz, Nicholas H.; Shaw, Tom; Heizler, Matthew T.; Perkins, Michael E; El Tabakh, Mohammed; Kunk, Michael J.

2016-01-01

Thick late Miocene nonmarine evaporite (mainly halite and gypsum) and related lacustrine limestone deposits compose the upper basin fill in half grabens within the Lake Mead region of the Basin and Range Province directly west of the Colorado Plateau in southern Nevada and northwestern Arizona. Regional relations and geochronologic data indicate that these deposits are late synextensional to postextensional (ca. 12–5 Ma), with major extension bracketed between ca. 16 and 9 Ma and the abrupt western margin of the Colorado Plateau established by ca. 9 Ma. Significant accommodation space in the half grabens allowed for deposition of late Miocene lacustrine and evaporite sediments. Concurrently, waning extension promoted integration of initially isolated basins, progressive enlargement of drainage nets, and development of broad, low gradient plains and shallow water bodies with extensive clastic, carbonate, and/or evaporite sedimentation. The continued subsidence of basins under restricted conditions also allowed for the preservation of particularly thick, localized evaporite sequences prior to development of the through-going Colorado River.The spatial and temporal patterns of deposition indicate increasing amounts of freshwater input during the late Miocene (ca. 12–6 Ma) immediately preceding arrival of the Colorado River between ca. 5.6 and 4.9 Ma. In axial basins along and proximal to the present course of the Colorado River, evaporite deposition (mainly gypsum) transitioned to lacustrine limestone progressively from east to west, beginning ca. 12–11 Ma in the Grand Wash Trough in the east and shortly after ca. 5.6 Ma in the western Lake Mead region. In several satellite basins to both the north and south of the axial basins, evaporite deposition was more extensive, with thick halite (>200 m to 2.5 km thick) accumulating in the Hualapai, Overton Arm, and northern Detrital basins. Gravity and magnetic lows suggest that thick halite may also lie within the

Estimation of residence time in a shallow lacustrine embayment

NASA Astrophysics Data System (ADS)

Razmi, A. M.; Barry, D. A.; Lemmin, U.; Bakhtyar, R.

2012-12-01

Near-shore water quality in lacustrine bays subjected to effluent or stream discharges is affected by, amongst other things, the residence time within a given bay. Vidy Bay, located on the northern shore of Lake Geneva, Switzerland, receives discharge from a wastewater treatment plant, the Chamberonne River and a storm-water drain. The residence time of water in the bay largely depends on water exchanges with the main basin (Grand Lac) of Lake Geneva. Field investigations and modeling of the hydrodynamics of Vidy Bay have shown that currents are variable, due mainly to wind variability over the lake. However, in broad terms there are two main current patterns in the bay, (i) currents are linked to large gyres in the Grand Lac, or (ii) currents are partially independent of the Grand Lac and are controlled by small-scale gyres within the bay. Residence times in Vidy Bay were computed using the hydrodynamic model Delft3D. Since the Vidy Bay shoreline follows a shallow arc, the definition of the off-shore extent of the bay is ambiguous. Here, the largest within-bay gyre is used. Particle tracking was conducted for each of the three discharges into the bay. Model results were computed using meteorological data for 2010, and thus include the natural variability in wind patterns and seasonal stratification. An analysis of the results shows that a water parcel from the waste water outfall has a residence time ranging from hours to days. The water residence time is minimum near to the surface and maximum at the near bottom layer. The results confirmed that wind force, thermal stratification, and water depth are the main factors influencing residence time.

Quasi-periodic recurrence of great and giant earthquakes in South-Central Chile inferred from lacustrine turbidite records

NASA Astrophysics Data System (ADS)

Strasser, M.; Moernaut, J.; Van Daele, M. E.; De Batist, M. A. O.

2017-12-01

Coastal paleoseismic records in south-central Chile indicate that giant megathrust earthquakes -such as in AD1960 (Mw9.5)- occur on average every 300 yrs. Based on geodetic data, it was postulated that the area already has the potential for a Mw8 earthquake. However, to estimate the probability for such a great earthquake from a paleo-perspective, one needs to reconstruct the long-term recurrence pattern of megathrust earthquakes. Here, we present two long lacustrine records, comprising up to 35 earthquake-triggered turbidites over the last 4800 yrs. Calibration of turbidite extent with historical earthquake intensity reveals a different macroseismic intensity threshold (≥VII½ vs. ≥VI½) for the generation of turbidites at the coring sites. The strongest earthquakes (≥VII½) have longer recurrence intervals (292 ±93 yrs) than earthquakes with intensity of ≥VI½ (139 ±69 yrs). The coefficient of variation (CoV) of inter-event times indicate that the strongest earthquakes recur in a quasi-periodic way (CoV: 0.32) and follow a normal distribution. Including also "smaller" earthquakes (Intensity down to VI½) increases the CoV (0.5) and fits best with a Weibull distribution. Regional correlation of our multi-threshold shaking records with coastal records of tsunami and coseismic subsidence suggests that the intensity ≥VII½ events repeatedly ruptured the same part of the megathrust over a distance of at least 300 km and can be assigned to a Mw ≥ 8.6. We hypothesize that a zone of high plate locking -identified by GPS data and large slip in AD 1960- acts as a dominant regional asperity, on which elastic strain builds up over several centuries and mostly gets released in quasi-periodic great and giant earthquakes. For the next 110 yrs, we infer an enhanced probability for a Mw 7.7-8.5 earthquake whereas the probability for a Mw ≥ 8.6 (AD1960-like) earthquake remains low.

Trial coring in LLRW trenches at Chalk River

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donders, R.E.; Killey, R.W.D.; Franklin, K.J.

1996-12-31

As part of a program to better characterize the low-hazard radioactive waste managed by AECL at Chalk River, coring techniques in waste trenches are being assessed. Trial coring has demonstrated that sampling in waste regions is possible, and that boreholes can be placed through the waste trenches. Such coring provides a valuable information gathering technique. Information available from trench coring includes: (1) trench cover depth, waste region depth, waste compaction level, and detailed stratigraphic data; (2) soil moisture content and facility drainage performance; (3) borehole gamma logs that indicate radiation levels in the region of the borehole; (4) biochemical conditionsmore » in the waste regions, vadose zone, and groundwater; (5) site specific information relevant to contaminant migration modelling or remedial actions; (6) information on contaminant releases and inventories. Boreholes through the trenches can also provide a means for early detection of potential contaminant releases.« less

Mixed biogenic and hydrothermal quartz in Permian lacustrine shale of Santanghu Basin, NW China: implications for penecontemporaneous transformation of silica minerals

NASA Astrophysics Data System (ADS)

Jiao, Xin; Liu, Yiqun; Yang, Wan; Zhou, Dingwu; Wang, Shuangshuang; Jin, Mengqi; Sun, Bin; Fan, Tingting

2018-01-01

The cycling of various isomorphs of authigenic silica minerals is a complex and long-term process. A special type of composite quartz (Qc) grains in tuffaceous shale of Permian Lucaogou Formation in the sediment-starved volcanically and hydrothermally active intracontinental lacustrine Santanghu rift basin (NW China) is studied in detail to demonstrate such processes. Samples from one well in the central basin were subject to petrographic, elemental chemical, and fluid inclusion analyses. About 200 Qc-bearing laminae are 0.1-2 mm and mainly 1 mm thick and intercalated within tuffaceous shale laminae. The Qc grains occur as framework grains and are dispersed in igneous feldspar-dominated matrix, suggesting episodic accumulation. The Qc grains are bedding-parallel, uniform in size (100 s µm), elongate, and radial in crystal pattern, suggesting a biogenic origin. Qc grains are composed of a core of anhedral microcrystalline quartz and an outer part of subhedral mega-quartz grains, whose edges are composed of small euhedral quartz crystals, indicating multiple episodic processes of recrystallization and overgrowth. Abundance of Al and Ti in quartz crystals and estimated temperature from fluid inclusions in Qc grains indicate that processes are related to hydrothermal fluids. Finally, the Qc grains are interpreted as original silica precipitation in microorganism (algae?) cysts, which were reworked by bottom currents and altered by hydrothermal fluids to recrystalize and overgrow during penecontemporaneous shallow burial. It is postulated that episodic volcanic and hydrothermal activities had changed lake water chemistry, temperature, and nutrient supply, resulting in variations in microorganic productivities and silica cycling. The transformation of authigenic silica from amorphous to well crystallized had occurred in a short time span during shallow burial.

Core Noise - Increasing Importance

NASA Technical Reports Server (NTRS)

Hultgren, Lennart S.

2011-01-01

This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduced-Perceived-Noise Technical Challenge; and the current research activities in the core-noise area, with additional details given about the development of a high-fidelity combustor-noise prediction capability as well as activities supporting the development of improved reduced-order, physics-based models for combustor-noise prediction. The need for benchmark data for validation of high-fidelity and modeling work and the value of a potential future diagnostic facility for testing of core-noise-reduction concepts are indicated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The SFW Reduced-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries. This reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. Noise generated in the jet engine core, by sources such as the compressor, combustor, and turbine, can be a significant contribution to the overall noise signature at low-power conditions, typical of approach flight. At high engine power during takeoff, jet and fan noise have traditionally dominated over core noise. However, current design trends and expected technological advances in engine-cycle design as well as noise-reduction methods are likely to reduce non-core noise even at engine-power points higher than approach. In addition, future low-emission combustor

Interface engineered ferrite@ferroelectric core-shell nanostructures: A facile approach to impart superior magneto-electric coupling

NASA Astrophysics Data System (ADS)

Abraham, Ann Rose; Raneesh, B.; Das, Dipankar; Oluwafemi, Oluwatobi Samuel; Thomas, Sabu; Kalarikkal, Nandakumar

2018-04-01

The electric field control of magnetism in multiferroics is attractive for the realization of ultra-fast and miniaturized low power device applications like nonvolatile memories. Room temperature hybrid multiferroic heterostructures with core-shell (0-0) architecture (ferrite core and ferroelectric shell) were developed via a two-step method. High-Resolution Transmission Electron Microscopy (HRTEM) images confirm the core-shell structure. The temperature dependant magnetization measurements and Mossbauer spectra reveal superparamagnetic nature of the core-shell sample. The ferroelectric hysteresis loops reveal leaky nature of the samples. The results indicate the promising applications of the samples for magneto-electric memories and spintronics.

Classification and sedimentary characteristics of lacustrine hyperpycnal channels: Triassic outcrops in the south Ordos Basin, central China

NASA Astrophysics Data System (ADS)

Xian, Benzhong; Wang, Junhui; Gong, Chenglin; Yin, Yu; Chao, Chuzhi; Liu, Jianping; Zhang, Guodong; Yan, Qi

2018-06-01

Subaquatic channels are known as active conduits for the delivery of terrigenous sediments into related marine and lacustrine basins, as well as important targets for hydrocarbon exploration. Compared to submarine channels, lacustrine subaqueous channels created by hyperpycnal flows are understudied. Using well-exposed outcrops collected from three different locations in the southern Ordos Basin, central China, morphologies and architecture of a channelized hyperpycnal system were studied and classified. Six facies associations represent sedimentary processes from strong erosion by bedload dominated hyperpycnal flows, to transitional deposition jointly controlled by bedload and suspended-load dominated hyperpycnal flows, finally to deposition from suspended-load dominated hyperpycnal flows. On the basis of channel morphologies, infilling sediments and sedimentary processes, the documented channels can be classified into four main categories, which are erosional, bedload dominated, suspended-load dominated, and depositional channels. In very proximal and very distal locations, erosional channels and depositional channels serve as two end-members, while in middle areas, bedload-dominated channels and suspended-load dominated channels are transitional types. Erosional channels, as a response to strong erosion from bedload dominated hyperpycnal flows on upper slope, were mainly filled by mud interbedded with thin sand beds. As flow energy decreases, bedload dominated channels develop on middle slopes, which are characterized mainly by under- to balanced sediment infillings with cross-bedded sandstones and/or minor massive sandstones. Compared to bedload dominated channels, suspended-load dominated channels mainly develop in deeper water, and were filled mainly by massive or planar-laminated sandstones. Depositional channels, as a response to suspended-load dominated hyperpycnal flows in deep-water areas, are characterized by thin-medium bed classical turbidites with

Interior of the Plum Brook Reactor Facility

NASA Image and Video Library

1961-02-21

A view inside the 55-foot high containment vessel of the National Aeronautics and Space Administration (NASA) Plum Brook Reactor Facility in Sandusky, Ohio. The 60-megawatt test reactor went critical for the first time in 1961 and began its full-power research operations in 1963. From 1961 to 1973, this reactor performed some of the nation’s most advanced nuclear research. The reactor was designed to determine the behavior of metals and other materials after long durations of irradiation. The materials would be used to construct a nuclear-powered rocket. The reactor core, where the chain reaction occurred, sat at the bottom of the tubular pressure vessel, seen here at the center of the shielding pool. The core contained fuel rods with uranium isotopes. A cooling system was needed to reduce the heat levels during the reaction. A neutron-impervious reflector was also employed to send many of the neutrons back to the core. The Plum Brook Reactor Facility was constructed from high-density concrete and steel to prevent the excess neutrons from escaping the facility, but the water in the pool shielded most of the radiation. The water, found in three of the four quadrants served as a reflector, moderator, and coolant. In this photograph, the three 20-ton protective shrapnel shields and hatch have been removed from the top of the pressure tank revealing the reactor tank. An overhead crane could be manipulated to reach any section of this room. It was used to remove the shrapnel shields and transfer equipment.

Carbon and nitrogen isotope composition of core catcher samples from the ICDP deep drilling at Laguna Potrok Aike (Patagonia, Argentina)

NASA Astrophysics Data System (ADS)

Luecke, Andreas; Wissel, Holger; Mayr*, Christoph; Oehlerich, Markus; Ohlendorf, Christian; Zolitschka, Bernd; Pasado Science Team

2010-05-01

Glacial (up to 22.0 per mil) are only sporadically reached down core. Compared to this, separated moss debris is remarkably 13C depleted with a minimum at 31.5 per mil. The nitrogen isotope ratios of glacial Laguna Potrok Aike sediments are lower (2.5 per mil) than those of the younger part of the record. The core catcher samples indicate several oscillations between 0.5 and 3.5 per mil. Data suggest a correlation between nitrogen isotopes and C/N ratios, but no linear relation between carbon isotopes and carbon content and an only weak relationship between carbon and nitrogen isotopes. Increasing nitrogen isotope values from 8000 cm downwards could probably be related to changed environmental conditions of Marine Isotope Stage 3 (MIS 3) compared to Marine Isotope Stage 2 (MIS 2). This will be further evaluated with higher resolution from the composite profile including a detailed study of discrete plant debris layers. References Haberzettl, T. et al. (2007). Lateglacial and Holocene wet-dry cycles in southern Patagonia: chronology, sedimentology and geochemistry of a lacustrine record from Laguna Potrok Aike, Argentina. The Holocene, 17: 297-310. Mayr, C. et al. (2009). Isotopic and geochemical fingerprints of environmental changes during the last 16,000 years on lacustrine organic matter from Laguna Potrok Aike (southern Patagonia, Argentina). Journal of Paleolimnology, 42: 81-102.

Defining the upper age limit of luminescence dating: A case study using long lacustrine records from Chew Bahir, Ethiopia

NASA Astrophysics Data System (ADS)

Chapot, Melissa S.; Roberts, Helen M.; Lamb, Henry F.; Schäbitz, Frank; Asrat, Asfawossen; Trauth, Martin H.

2017-04-01

present study explores a means of defining the upper limit for reliable luminescence ages for sedimentary records without an established chronologic framework, using a long ( 280m; Cohen et al., 2016) lacustrine record from Chew Bahir, Ethiopia, drilled as part of the Hominin Sites and Paleolakes Drilling Project (HSPDP) of the International Continental Scientific Drilling Programme (ICDP) and CRC806 "Our way to Europe". Natural saturation of OSL signals is explored by plotting natural signal intensity against depth, creating a pseudo-Natural DRC that can be compared to laboratory DRCs. Unlike the homogenous deposits of the Chinese Loess Plateau where the Natural DRC concept was developed, the 280m composite core from Chew Bahir shows significant variation in lithology enabling investigation of the effects of sample to sample variability on Natural DRC construction, and facilitating comparison between signals from fine-quartz, fine-polymineral, and coarse-potassium feldspar grains. This work demonstrates how the concepts of Natural DRCs can be used to define the upper dating limit of sample suites without independent age control, providing valuable information for long sedimentary sequences such as the lacustrine deposits from Chew Bahir. Chapot M.S., et al. (2012), Radiation Measurements 47: 1045-1052. Cohen A, et al. (2016), Scientific Drilling 21: 1-16. Wintle, A.G., Murray, A.S. (2006) Radiation Measurements 41: 369-391.

Facile synthesis of Ag@ZIF-8 core-shell heterostructure nanowires for improved antibacterial activities

NASA Astrophysics Data System (ADS)

Guo, Yu-Feng; Fang, Wei-Jun; Fu, Jie-Ru; Wu, Yun; Zheng, Jun; Gao, Gui-Qi; Chen, Cheng; Yan, Rui-Wen; Huang, Shou-Guo; Wang, Chun-Chang

2018-03-01

Compared with pure MOFs, core-shell heterostructures of noble-metal@MOFs have attracted tremendous interest due to their unique structure and extensive applications. In the present study, we have successfully synthesized well-defined core-shell Ag@ZIF-8 nanowires. The products growth process has been investigated by examining the products obtained at different intervals and the thickness of ZIF-8 shell ranging from 30 to 100 nm can be technically obtained by tuning the quantity of Ag nanowires. Ag@ZIF-8 has been proven to possess large specific surfaces and high thermal stability. Additionally, the antibacterial activity of Ag@ZIF-8 is further tested against Bacillus subtilis and Escherichia coli BL21. The results reveal that Ag@ZIF-8 core-shell heterostructure nanowires have effective activities against the two types of bacterial strains.

Intramolecular Redox-Mannich Reactions: Facile Access to the Tetrahydroprotoberberine Core.

PubMed

Ma, Longle; Seidel, Daniel

2015-09-07

Cyclic amines such as pyrrolidine undergo redox-annulations with 2-formylaryl malonates. Concurrent oxidative amine α-CH bond functionalization and reductive N-alkylation render this transformation redox-neutral. This redox-Mannich process provides regioisomers of classic Reinhoudt reaction products as an entry to the tetrahydroprotoberberine core, enabling the synthesis of (±)-thalictricavine and its epimer. An unusually mild amine-promoted dealkoxycarbonylation was discovered in the course of these studies. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The National Ignition Facility: Transition to a User Facility

NASA Astrophysics Data System (ADS)

Moses, E. I.; Atherton, J.; Lagin, L.; Larson, D.; Keane, C.; MacGowan, B.; Patterson, R.; Spaeth, M.; Van Wonterghem, B.; Wegner, P.; Kauffman, R.

2016-03-01

The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) has been operational since March 2009 and has been transitioning to a user facility supporting ignition science, high energy density science (HEDS), national security applications, and fundamental science. The facility has achieved its design goal of 1.8 MJ and 500 TW of 3ω light on target, and has performed target experiments with 1.9 MJ at peak powers of 410 TW. The facility is on track to perform over 200 target shots this year in support of all of its user communities. The facility has nearly 60 diagnostic systems operational and has shown flexibility in laser pulse shape and performance to meet the requirements of its multiple users. Progress continues on its goal of demonstrating thermonuclear burn in the laboratory. It has performed over 40 indirect-drive experiments with cryogenic-layered capsules. New platforms are being developed for HEDS and fundamental science. Equation-of-state and material strength experiments have been done on a number of materials with pressures of over 50 MBars obtained in diamond, conditions never previously encountered in the laboratory and similar to those found in planetary interiors. Experiments are also in progress investigating radiation transport, hydrodynamic instabilities, and direct drive implosions. NIF continues to develop as an experimental facility. Advanced Radiographic Capability (ARC) is now being installed on NIF for producing high-energy radiographs of the imploded cores of ignition targets and for short pulse laser-plasma interaction experiments. One NIF beam is planned for conversion to two picosecond beams in 2014. Other new diagnostics such as x-ray Thomson scattering, low energy neutron spectrometer, and multi-layer reflecting x-ray optics are also planned. Incremental improvements in laser performance such as improved optics damage performance, beam balance, and back reflection control are being pursued.

Parallel changes of taxonomic interaction networks in lacustrine bacterial communities induced by a polymetallic perturbation

PubMed Central

Laplante, Karine; Sébastien, Boutin; Derome, Nicolas

2013-01-01

Heavy metals released by anthropogenic activities such as mining trigger profound changes to bacterial communities. In this study we used 16S SSU rRNA gene high-throughput sequencing to characterize the impact of a polymetallic perturbation and other environmental parameters on taxonomic networks within five lacustrine bacterial communities from sites located near Rouyn-Noranda, Quebec, Canada. The results showed that community equilibrium was disturbed in terms of both diversity and structure. Moreover, heavy metals, especially cadmium combined with water acidity, induced parallel changes among sites via the selection of resistant OTUs (Operational Taxonomic Unit) and taxonomic dominance perturbations favoring the Alphaproteobacteria. Furthermore, under a similar selective pressure, covariation trends between phyla revealed conservation and parallelism within interphylum interactions. Our study sheds light on the importance of analyzing communities not only from a phylogenetic perspective but also including a quantitative approach to provide significant insights into the evolutionary forces that shape the dynamic of the taxonomic interaction networks in bacterial communities. PMID:23789031

Millennial-scale climate variations recorded in Early Pliocene colour reflectance time series from the lacustrine Ptolemais Basin (NW Greece)

NASA Astrophysics Data System (ADS)

Steenbrink, J.; Kloosterboer-van Hoeve, M. L.; Hilgen, F. J.

2003-03-01

Quaternary climate proxy records show compelling evidence for climate variability on time scales of a few thousand years. The causes for these millennial-scale or sub-Milankovitch cycles are still poorly understood, not least due to the complex feedback mechanisms of large ice sheets during the Quaternary. We present evidence of millennial-scale climate variability in Early Pliocene lacustrine sediments from the intramontane Ptolemais Basin in northwestern Greece. The sediments are well exposed in a series of open-pit lignite mines and exhibit a distinct millennial-scale sedimentary cyclicity of alternating lignites and lacustrine marl beds that resulted from precession-induced variations in climate. The higher-frequency, millennial-scale cyclicity is particularly prominent within the grey-coloured marl segment of individual cycles. A stratigraphic interval of ˜115 ka, covering five precession-induced sedimentary cycles, was studied in nine parallel sections from two open-pit lignite mines located several km apart. High-resolution colour reflectance records were used to quantify the within-cycle variability and to determine its lateral continuity. Much of the within-cycle variability could be correlated between the parallel sections, even in fine detail, which suggests that these changes reflect basin-wide variations in environmental conditions related to (regional) climate fluctuations. Interbedded volcanic ash beds demonstrate the synchronicity of these fluctuations and spectral analysis of the reflectance time series shows a significant concentration of within-cycle variability at periods of ˜11, ˜5.5 and ˜2 ka. The occurrence of variability at such time scales at times before the intensification of the Northern Hemisphere glaciation suggests that they cannot solely have resulted from internal ice-sheet dynamics. Possible candidates include harmonics or combination tones of the main orbital cycles, variations in solar output or periodic motions of the Earth

Unique phenomenon of the accumulation of terrestrial metal iron particles in lacustrine deposits: Zhombolok volcanic region, East Sayan

NASA Astrophysics Data System (ADS)

Pechersky, D. M.; Kazanskii, A. Yu.; Markov, G. P.; Tselmovich, V. A.; Shchetnikov, A. A.

2018-01-01

The native iron particles that were previously detected by thermomagnetic and microprobe analyses in the sediments of different age in many regions of the world are of extraterrestrial origin. The similarity in the compositions, grain shapes, and sizes observed in the extraterrestrial and terrestrial particles of native iron testifies to the common production conditions of iron particles during the formation of planets. In this paper, the single finding of terrestrial iron in the lacustrine sediments of the Zhombolok volcanic region, East Sayan, is discussed. The uniqueness of the results indicates that the spatial distribution of the particles of native iron is limited to a fairly narrow area around their source—volcanic eruption or/and the fall of a large meteorite.

Lunar Polar Coring Lander

NASA Technical Reports Server (NTRS)

Angell, David; Bealmear, David; Benarroche, Patrice; Henry, Alan; Hudson, Raymond; Rivellini, Tommaso; Tolmachoff, Alex

1990-01-01

Plans to build a lunar base are presently being studied with a number of considerations. One of the most important considerations is qualifying the presence of water on the Moon. The existence of water on the Moon implies that future lunar settlements may be able to use this resource to produce things such as drinking water and rocket fuel. Due to the very high cost of transporting these materials to the Moon, in situ production could save billions of dollars in operating costs of the lunar base. Scientists have suggested that the polar regions of the Moon may contain some amounts of water ice in the regolith. Six possible mission scenarios are suggested which would allow lunar polar soil samples to be collected for analysis. The options presented are: remote sensing satellite, two unmanned robotic lunar coring missions (one is a sample return and one is a data return only), two combined manned and robotic polar coring missions, and one fully manned core retrieval mission. One of the combined manned and robotic missions has been singled out for detailed analysis. This mission proposes sending at least three unmanned robotic landers to the lunar pole to take core samples as deep as 15 meters. Upon successful completion of the coring operations, a manned mission would be sent to retrieve the samples and perform extensive experiments of the polar region. Man's first step in returning to the Moon is recommended to investigate the issue of lunar polar water. The potential benefits of lunar water more than warrant sending either astronauts, robots or both to the Moon before any permanent facility is constructed.

Core-Shell PdPb@Pd Aerogels with Multiply-Twinned Intermetallic Nanostructures: Facile Synthesis with Accelerated Gelation Kinetics and Their Enhanced Electrocatalytic Properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu, Chengzhou; Shi, Qiurong; Fu, Shaofang

2018-04-04

Delicately engineering the well-defined noble metal aerogels with favorable structural and compositional features is of vital importance for wide applications. Here, we reported one-pot and facile method for synthesizing core-shell PdPb@Pd hydrogels/aerogels with multiply-twinned grains and ordered intermetallic phase using sodium hypophosphite as a multifunctional reducing agent. Due to the accelerated gelation kinetics induced by increased reaction temperature and specific function of sodium hypophosphite, the formation of hydrogels can be completed within 4 hrs, far faster than the previous reports. Owe to their unique porous structure and favorable geometric and electronic effects, the optimized PdPb@Pd aerogels exhibit enhanced electrochemical performancemore » towards ethylene glycol oxidation with a mass activity of 5.8 times higher than Pd black.« less

Sulfate reduction controlled by organic matter availability in deep sediment cores from the saline, alkaline Lake Van (Eastern Anatolia, Turkey)

PubMed Central

Glombitza, Clemens; Stockhecke, Mona; Schubert, Carsten J.; Vetter, Alexandra; Kallmeyer, Jens

2013-01-01

As part of the International Continental Drilling Program deep lake drilling project PaleoVan, we investigated sulfate reduction (SR) in deep sediment cores of the saline, alkaline (salinity 21.4‰, alkalinity 155 m mEq-1, pH 9.81) Lake Van, Turkey. The cores were retrieved in the Northern Basin (NB) and at Ahlat Ridge (AR) and reached a maximum depth of 220 m. Additionally, 65–75 cm long gravity cores were taken at both sites. SR rates (SRR) were low (≤22 nmol cm-3 day-1) compared to lakes with higher salinity and alkalinity, indicating that salinity and alkalinity are not limiting SR in Lake Van. Both sites differ significantly in rates and depth distribution of SR. In NB, SRR are up to 10 times higher than at AR. SR could be detected down to 19 mblf (meters below lake floor) at NB and down to 13 mblf at AR. Although SRR were lower at AR than at NB, organic matter (OM) concentrations were higher. In contrast, dissolved OM in the pore water at AR contained more macromolecular OM and less low molecular weight OM. We thus suggest, that OM content alone cannot be used to infer microbial activity at Lake Van but that quality of OM has an important impact as well. These differences suggest that biogeochemical processes in lacustrine sediments are reacting very sensitively to small variations in geological, physical, or chemical parameters over relatively short distances. PMID:23908647

Evidence for a core gut microbiota in the zebrafish

PubMed Central

Roeselers, Guus; Mittge, Erika K; Stephens, W Zac; Parichy, David M; Cavanaugh, Colleen M; Guillemin, Karen; Rawls, John F

2011-01-01

Experimental analysis of gut microbial communities and their interactions with vertebrate hosts is conducted predominantly in domesticated animals that have been maintained in laboratory facilities for many generations. These animal models are useful for studying coevolved relationships between host and microbiota only if the microbial communities that occur in animals in lab facilities are representative of those that occur in nature. We performed 16S rRNA gene sequence-based comparisons of gut bacterial communities in zebrafish collected recently from their natural habitat and those reared for generations in lab facilities in different geographic locations. Patterns of gut microbiota structure in domesticated zebrafish varied across different lab facilities in correlation with historical connections between those facilities. However, gut microbiota membership in domesticated and recently caught zebrafish was strikingly similar, with a shared core gut microbiota. The zebrafish intestinal habitat therefore selects for specific bacterial taxa despite radical differences in host provenance and domestication status. PMID:21472014

Sediment Coring of the Proglacial Lake Donguz-Orun (northern Caucasus, Russia)

NASA Astrophysics Data System (ADS)

Alexandrin, Mikhail; Solomina, Olga; Kalugin, Ivan; Darin, Andrey; Nesje, Atle

2014-05-01

So far, no high-resolution reconstructions of climate and glacier variations based on lake sediment properties are available in Caucasus Mountains. In other presently glaciated regions this approach is proved to be very useful for this purpose (e.g. Nesje et al., 2001, 2011; Bakke, 2005, Nesje, 2009) In this paper we report the first results of the sediment coring of Donguz-Orun Lake (N 43°13'26", E 42°29'35") situated in the upper reaches of Donguz-Orun-Kyol, a tributary of Baksan river in the Elbrus region of Northern Caucasus, a typical proglacial lake dammed by a lateral moraine deposited by the Donguz-Orun Glacier. It is a drainage lake with several inflowing glacial streams and effluent river Donguz-Orun. The surface area is around 105 000 m2 with a water volume of 465 000m3. The average water depth is around 4.5 m, with a maximum water depth of 14 m. The deepest part is found close to the moraine dam in the narrow northern part of the lake. This is normally consistent with this type of glacial lake systems. An intensive gravitational drift of the moraine material towards the lake is observed. These non-rounded moraine boulders constitute a significant part of the lakebed. Lacustrine sediments are present though. The coring campaign from Institute of Geography, Russian Academy of Sciences (August 2012) used a modified piston corer with a 110 mm-diameter plastic tube (Nesje, 1992) mounted on the inflatable catamaran to obtain lake sediments from Lake Donguz-Orun. A 28-cm long core was retrieved from a water depth of around 7 m. The sediments consist of regularly laminated, fine beige clay, with several interlayers of sand. The coring process appeared to be challenging due to the stiffness of clay, which led to extreme bending of the sediment layers in the basal part of the core. The original thickness of the sediments was obviously higher than observed in the core. In order to clarify the recent history of the Donguz-Orun glacier, we used lichenometry and

NCI Core Open House Shines Spotlight on Supportive Science and Basic Research | Poster

Cancer.gov

The lobby of Building 549 at NCI at Frederick bustled with activity for two hours on Tuesday, May 1, as several dozen scientists and staff gathered for the NCI Core Open House. The event aimed to encourage discussion and educate visitors about the capabilities of the cores, laboratories, and facilities that offer support to NCI’s Center for Cancer Research.

Microbially mediated carbon cycling at the Cenomanian-Turonian transition in lacustrine environments

NASA Astrophysics Data System (ADS)

Wu, H.; Zhang, S.; Jiang, G.; Underwood, M.; Wan, X.

2009-12-01

The Late Cretaceous Cenomanian-Turonian (C-T) transition records a major ocean anoxic event (OAE2) and a positive carbon isotope excursion. These events have been documented mostly from marine successions and their expression in terrestrial environments is highly desirable. Here we report a high-resolution organic carbon isotope record across the C-T boundary from the Qingshankou Formation (K2qn) of the terrestrial Songliao Basin (SLB) in northeastern China. Samples were collected from the drilled core (SK-1) and cover the bottom 60 m of the K2qn that has been correlated to the C-T transition using the astronomical time scale. The results show a long-term negative δ13Corg excursion superimposed on short-term δ13Corg cycles. Most δ13Corg cycles have a reverse relationship with total organic carbon (TOC) concentration, except at the beginning and the end of the long-term δ13Corg excursion. Spectral analysis of the δ13Corg, TOC and Gamma Ray Logging curves (GR) reveals three distinct cycle bands with the thickness of 14.5-9.0m, 5.8-3.4m and 2.2-1.5m, which were interpreted as the short eccentricity, obliquity, and precession cycles, respectively. The investigated section recorded about 7 short eccentricity and 39 precession cycles. The reverse relationship between TOC and δ13Corg is inconsistent with the general TOC-δ13Corg pattern seen in most lacustrine environments, in which increasing primary productivity (and thus TOC) in the epilimnion results in higher δ13Corg values. In combination with existing biomarker data from K2qn, the TOC-δ13Corg pattern in SLB is better explained by microbially mediated carbon cycling that is astronomically controlled by the precession cycles. During precession minima (summer insolation maxima) periods, intensified precipitation and increased chemical weathering may have led to sustained eutrophication in SLB and the bloom of chemoautotrophic and methanotrophic organisms in the basin. Significant biomass contribution from

One-pot facile synthesis of reusable tremella-like M1@M2@M1(OH)2 (M1 = Co, Ni, M2 = Pt/Pd, Pt, Pd and Au) three layers core-shell nanostructures as highly efficient catalysts

NASA Astrophysics Data System (ADS)

Liu, Yadong; Fang, Zhen; Kuai, Long; Geng, Baoyou

2014-07-01

In this work, a general, facile, successive and eco-friendly method for multilayer nanostructures has been established for the first time. We take full advantage of the structural and compositional character of M1@M2 (M1 = Co, Ni, M2 = Pt/Pd, Pt, Pd and Au) core-shell nanostructures to prepare a series of reusable tremella-like M1@M2@M1(OH)2 three layer core-shell or yolk-shell nanocomposites with a magnetic core, a porous noble metal shell, and an ultrathin cobalt or nickel hydroxide shell. We evaluated their catalytic performance using a model reaction based on the reduction of 4-nitrophenol. These novel M1@M2@M1(OH)2 nanomaterials with a unique internal micro environment promoted the efficiency of the catalytic reaction, prolonged the service life of the catalyst and enhanced the overall activity of the catalyst in the catalytic process. The novel three layer core-shell nanocomposites can be extended to other applications such as biomedical detection, energy conversion and storage systems.In this work, a general, facile, successive and eco-friendly method for multilayer nanostructures has been established for the first time. We take full advantage of the structural and compositional character of M1@M2 (M1 = Co, Ni, M2 = Pt/Pd, Pt, Pd and Au) core-shell nanostructures to prepare a series of reusable tremella-like M1@M2@M1(OH)2 three layer core-shell or yolk-shell nanocomposites with a magnetic core, a porous noble metal shell, and an ultrathin cobalt or nickel hydroxide shell. We evaluated their catalytic performance using a model reaction based on the reduction of 4-nitrophenol. These novel M1@M2@M1(OH)2 nanomaterials with a unique internal micro environment promoted the efficiency of the catalytic reaction, prolonged the service life of the catalyst and enhanced the overall activity of the catalyst in the catalytic process. The novel three layer core-shell nanocomposites can be extended to other applications such as biomedical detection, energy conversion and

Impact of environmental factors on couplings between bacterial community composition and ectoenzymatic activities in a lacustrine ecosystem.

PubMed

Boucher, Delphine; Debroas, Didier

2009-10-01

This study examined the effects of temporal changes in bacterial community composition (BCC) and environmental factors on potential ectoenzymatic activities (alpha-glucosidase, beta-glucosidase, alkaline phosphatase and leucine aminopeptidase) in a lacustrine ecosystem (Sep reservoir, France). BCC was assessed by terminal restriction fragment length polymorphism. Physical parameters, and inorganic and organic nutrient concentrations (dissolved carbohydrates and proteins) were measured in lakes and tributaries. According to the multivariate statistics (redundancy analysis), physical and chemical factors explained the largest part of leucine aminopeptidase activity, whereas the temporal changes of other ectoenzymatic activities were partly dependent on the variations in the BCC. In particular, the occurrence of occasional bacterial populations seemed to explain a lot of the variation in rates and patterns of polymer hydrolysis. The relation observed in this study between the bacterial structure and activity is discussed within the framework of biodiversity-ecosystem functioning.

The NASA Lewis Research Center Internal Fluid Mechanics Facility

NASA Technical Reports Server (NTRS)

Porro, A. R.; Hingst, W. R.; Wasserbauer, C. A.; Andrews, T. B.

1991-01-01

An experimental facility specifically designed to investigate internal fluid duct flows is described. It is built in a modular fashion so that a variety of internal flow test hardware can be installed in the facility with minimal facility reconfiguration. The facility and test hardware interfaces are discussed along with design constraints of future test hardware. The plenum flow conditioning approach is also detailed. Available instrumentation and data acquisition capabilities are discussed. The incoming flow quality was documented over the current facility operating range. The incoming flow produces well behaved turbulent boundary layers with a uniform core. For the calibration duct used, the boundary layers approached 10 percent of the duct radius. Freestream turbulence levels at the various operating conditions varied from 0.64 to 0.69 percent of the average freestream velocity.

A facile one-pot oxidation-assisted dealloying protocol to massively synthesize monolithic core-shell architectured nanoporous copper@cuprous oxide nanonetworks for photodegradation of methyl orange

PubMed Central

Liu, Wenbo; Chen, Long; Dong, Xin; Yan, Jiazhen; Li, Ning; Shi, Sanqiang; Zhang, Shichao

2016-01-01

In this report, a facile and effective one-pot oxidation-assisted dealloying protocol has been developed to massively synthesize monolithic core-shell architectured nanoporous copper@cuprous oxide nanonetworks (C-S NPC@Cu2O NNs) by chemical dealloying of melt-spun Al 37 at.% Cu alloy in an oxygen-rich alkaline solution at room temperature, which possesses superior photocatalytic activity towards photodegradation of methyl orange (MO). The experimental results show that the as-prepared nanocomposite exhibits an open, bicontinuous interpenetrating ligament-pore structure with length scales of 20 ± 5 nm, in which the ligaments comprising Cu and Cu2O are typical of core-shell architecture with uniform shell thickness of ca. 3.5 nm. The photodegradation experiments of C-S NPC@Cu2O NNs show their superior photocatalytic activities for the MO degradation under visible light irradiation with degradation rate as high as 6.67 mg min−1 gcat−1, which is a diffusion-controlled kinetic process in essence in light of the good linear correlation between photodegradation ratio and square root of irradiation time. The excellent photocatalytic activity can be ascribed to the synergistic effects between unique core-shell architecture and 3D nanoporous network with high specific surface area and fast mass transfer channel, indicating that the C-S NPC@Cu2O NNs will be a promising candidate for photocatalysts of MO degradation. PMID:27830720

A facile one-pot oxidation-assisted dealloying protocol to massively synthesize monolithic core-shell architectured nanoporous copper@cuprous oxide nanonetworks for photodegradation of methyl orange

NASA Astrophysics Data System (ADS)

Liu, Wenbo; Chen, Long; Dong, Xin; Yan, Jiazhen; Li, Ning; Shi, Sanqiang; Zhang, Shichao

2016-11-01

In this report, a facile and effective one-pot oxidation-assisted dealloying protocol has been developed to massively synthesize monolithic core-shell architectured nanoporous copper@cuprous oxide nanonetworks (C-S NPC@Cu2O NNs) by chemical dealloying of melt-spun Al 37 at.% Cu alloy in an oxygen-rich alkaline solution at room temperature, which possesses superior photocatalytic activity towards photodegradation of methyl orange (MO). The experimental results show that the as-prepared nanocomposite exhibits an open, bicontinuous interpenetrating ligament-pore structure with length scales of 20 ± 5 nm, in which the ligaments comprising Cu and Cu2O are typical of core-shell architecture with uniform shell thickness of ca. 3.5 nm. The photodegradation experiments of C-S NPC@Cu2O NNs show their superior photocatalytic activities for the MO degradation under visible light irradiation with degradation rate as high as 6.67 mg min-1 gcat-1, which is a diffusion-controlled kinetic process in essence in light of the good linear correlation between photodegradation ratio and square root of irradiation time. The excellent photocatalytic activity can be ascribed to the synergistic effects between unique core-shell architecture and 3D nanoporous network with high specific surface area and fast mass transfer channel, indicating that the C-S NPC@Cu2O NNs will be a promising candidate for photocatalysts of MO degradation.

Scientific Design of the New Neutron Radiography Facility (SANRAD) at SAFARI-1 for South Africa

NASA Astrophysics Data System (ADS)

de Beer, F. C.; Gruenauer, F.; Radebe, J. M.; Modise, T.; Schillinger, B.

The final scientific design for an upgraded neutron radiography/tomography facility at beam port no.2 of the SAFARI-1 nuclear research reactor has been performed through expert advice from Physics Consulting, FRMII in Germany and IPEN, Brazil. A need to upgrade the facility became apparent due to the identification of various deficiencies of the current SANRAD facility during an IAEA-sponsored expert mission of international scientists to Necsa, South Africa. A lack of adequate shielding that results in high neutron background on the beam port floor, a mismatch in the collimator aperture to the core that results in a high gradient in neutron flux on the imaging plane and due to a relative low L/D the quality of the radiographs are poor, are a number of deficiencies to name a few.The new design, based on results of Monte Carlo (MCNP-X) simulations of neutron- and gamma transport from the reactor core and through the new facility, is being outlined. The scientific design philosophy, neutron optics and imaging capabilities that include the utilization of fission neutrons, thermal neutrons, and gamma-rays emerging from the core of SAFARI-1 are discussed.

Critical need for MFE: the Alcator DX advanced divertor test facility

NASA Astrophysics Data System (ADS)

Vieira, R.; Labombard, B.; Marmar, E.; Irby, J.; Wolf, S.; Bonoli, P.; Fiore, C.; Granetz, R.; Greenwald, M.; Hutchinson, I.; Hubbard, A.; Hughes, J.; Lin, Y.; Lipschultz, B.; Parker, R.; Porkolab, M.; Reinke, M.; Rice, J.; Shiraiwa, S.; Terry, J.; Theiler, C.; Wallace, G.; White, A.; Whyte, D.; Wukitch, S.

2013-10-01

Three critical challenges must be met before a steady-state, power-producing fusion reactor can be realized: how to (1) safely handle extreme plasma exhaust power, (2) completely suppress material erosion at divertor targets and (3) do this while maintaining a burning plasma core. Advanced divertors such as ``Super X'' and ``X-point target'' may allow a fully detached, low temperature plasma to be produced in the divertor while maintaining a hot boundary layer around a clean plasma core - a potential game-changer for magnetic fusion. No facility currently exists to test these ideas at the required parallel heat flux densities. Alcator DX will be a national facility, employing the high magnetic field technology of Alcator combined with high-power ICRH and LHCD to test advanced divertor concepts at FNSF/DEMO power exhaust densities and plasma pressures. Its extended vacuum vessel contains divertor cassettes with poloidal field coils for conventional, snowflake, super-X and X-point target geometries. Divertor and core plasma performance will be explored in regimes inaccessible in conventional devices. Reactor relevant ICRF and LH drivers will be developed, utilizing high-field side launch platforms for low PMI. Alcator DX will inform the conceptual development and accelerate the readiness-for-deployment of next-step fusion facilities.

Multidisciplinary distinction of mass-movement and flood-induced deposits in lacustrine environments: implications for Holocene palaeohydrology and natural hazards (Lake Ledro, Southern Alps, Italy)

NASA Astrophysics Data System (ADS)

Simonneau, A.; Chapron, E.; Vannière, B.; Wirth, S. B.; Gilli, A.; Di Giovanni, C.; Anselmetti, F. S.; Desmet, M.; Magny, M.

2012-08-01

High-resolution seismic profiles and sediment cores from Lake Ledro combined with soil and river-bed samples from the lake's catchment area are used to assess the recurrence of natural hazards (earthquakes and flood events) in the southern Italian Alps during the Holocene. Two well-developed deltas and a flat central basin are identified on seismic profiles in Lake Ledro. Lake sediments are finely laminated in the basin since 9000 cal. yr BP and frequently interrupted by two types of sedimentary events: light-coloured massive layers and dark-coloured graded beds. Optical analysis (quantitative organic petrography) of the organic matter occurring in soils, river beds and lacustrine samples together with lake-sediment bulk density and grain-size analysis illustrate that light-coloured layers consist of a mixture of lacustrine sediments and mainly contain algal particles similar to the ones observed in background sediments. Light-coloured layers thicker than 1.5 cm in the main basin of Lake Ledro are dense and synchronous to numerous coeval mass-wasting deposits remoulding the slopes of the basin. They are interpreted as subaquatic mass movements triggered by historical and pre-historical regional earthquakes dated to 2005 AD, 1891 AD, 1045 AD and 1260, 2545, 2595, 3350, 3815, 4740, 7190, 9185 and 11495 cal. yr BP. Dark-coloured sedimentary event are dense and develop high-amplitude reflections in front of the deltas and in the deep central basin. These beds are mainly made of terrestrial organic matter (soils and ligno-cellulosic debris) and are interpreted as resulting from intense hyperpycnal flood events. Mapping and quantifying the amount of soil material accumulated in the Holocene hyperpycnal flood deposits of the sequence and applying the De Ploey erosion model allow estimating that the equivalent soil thickness eroded over the catchment area reached up to 4 mm during the largest Holocene flood events. Such significant soil erosion is interpreted as resulting

Hypervelocity Impact Evaluation of Metal Foam Core Sandwich Structures

NASA Technical Reports Server (NTRS)

Yasensky, John; Christiansen, Eric L.

2007-01-01

A series of hypervelocity impact (HVI) tests were conducted by the NASA Johnson Space Center (JSC) Hypervelocity Impact Technology Facility (HITF) [1], building 267 (Houston, Texas) between January 2003 and December 2005 to test the HVI performance of metal foams, as compared to the metal honeycomb panels currently in service. The HITF testing was conducted at the NASA JSC White Sands Testing Facility (WSTF) at Las Cruces, New Mexico. Eric L. Christiansen, Ph.D., and NASA Lead for Micro-Meteoroid Orbital Debris (MMOD) Protection requested these hypervelocity impact tests as part of shielding research conducted for the JSC Center Director Discretionary Fund (CDDF) project. The structure tested is a metal foam sandwich structure; a metal foam core between two metal facesheets. Aluminum and Titanium metals were tested for foam sandwich and honeycomb sandwich structures. Aluminum honeycomb core material is currently used in Orbiter Vehicle (OV) radiator panels and in other places in space structures. It has many desirable characteristics and performs well by many measures, especially when normalized by density. Aluminum honeycomb does not perform well in Hypervelocity Impact (HVI) Testing. This is a concern, as honeycomb panels are often exposed to space environments, and take on the role of Micrometeoroid / Orbital Debris (MMOD) shielding. Therefore, information on possible replacement core materials which perform adequately in all necessary functions of the material would be useful. In this report, HVI data is gathered for these two core materials in certain configurations and compared to gain understanding of the metal foam HVI performance.

Video Intertank for the Core Stage for the first SLS Flight

NASA Image and Video Library

2017-06-29

This video shows the Space Launch System interank, which recently completed assembly at NASA's Michoud Assembly Facility in New Orleans. This tank was bolted together with more than 7,000 bolts. It is the only part of the SLS core stage assembly with bolts rather than by welding. The rocket's interank is located between the core stage liquid oxygen and liquid hydrogen fuel tanks. It has to be strong because the two SLS solid rocket boosters attache to the sides of it. This flight article will be connected to four other parts to form the core stage for the first integrated flight of SLS and Orion.

Approaches to N-Methylwelwitindolinone C Isothiocyanate: Facile Synthesis of the Tetracyclic Core

PubMed Central

Heidebrecht, Richard W.; Gulledge, Brian; Martin, Stephen F.

2010-01-01

The synthesis of a functionalized, tetracyclic core of N-methylwelwitindolinone C isothiocyanate is reported. The approach features a convergent coupling between an indole iminium ion and a highly functionalized vinylogous silyl ketene acetal followed by an intramolecular palladium-catalyzed cyclization that proceeds via an enolate arylation. PMID:20446675

Vice President Pence Visits SLS Engineering Test Facility

NASA Image and Video Library

2017-09-25

The Vice President toured the SLS engineering facility where the engine section of the rocket’s massive core stage is undergoing a major stress test. The rocket’s four RS-25 engines and the two solid rocket boosters that attach to the SLS engine section will produce more than 8 million pounds of thrust to launch the Orion spacecraft beyond low-Earth orbit. More than 3,000 measurements using sensors installed on the test section will help ensure the core stage for all SLS missions can withstand the extreme forces of flight.

The Lacustrine Upper Brushy Basin Member of the Morrison Formation, Four Corners Region, Usa: a Lithological and Mineralogical Terrestrial Analog for Gale Crater, Mars

NASA Astrophysics Data System (ADS)

Potter-McIntyre, S. L.; Chan, M. A.; McPherson, B. J.

2013-12-01

The upper part of the Jurassic Brushy Basin Member of the Morrison Formation is an iron- and clay-rich volcaniclastic shale deposited in an ephemeral alkaline saline lake system. Sedimentary rocks exposed in Gale Crater consist of similar non-acidic clays, possibly of lacustrine origin. Three primary clastic lithofacies are present in both the Brushy Basin Member and at Gale Crater: silt-/claystone, sandstone, and conglomerate. Both the terrestrial and martian silt-/claystone lithofacies are interpreted as lacustrine depositional environments due to features such as parallel laminated and massive sedimentary structures. Vugs are present in the siltstone/claystone facies on both the Colorado Plateau and at Gale Crater. Fluvial features are also observed in both examples such as cross-bedded sandstones and imbricated conglomerates. Concretions are present in both the Colorado Plateau and Gale Crater units. The vugs in the Brushy Basin Member preserve algal forms with cellular elaboration and are interpreted as charophyte molds. Two distinct suites of elements (1. C, Fe, As, P and, 2. C, S, Se, P) are associated with the microbial fossils and may be potential markers for biosignatures. Vugs at Gale Crater are a potential target to investigate the possibility of preserved microbial (algal) life where early analyses show the presence of the elements capable of supporting life. The Brushy Basin Member is composed predominately of quartz, feldspars, zeolites and altered volcanic ash. The abundant clay minerals in both the terrestrial and martian examples are hypothesized to have formed due to partial alteration of volcanic minerals in alkaline fluid. Similarly, concretions present in the terrestrial unit exhibit a diverse range of mineralogies likely due to alkaline fluid chemistries interacting with reactive volcaniclastic sediments. Terrestrial concretion mineralogy is diverse even within an outcrop or stratigraphic horizon which suggests reactants to precipitate

Tools and techniques for developing tephra stratigraphies in lake cores: A case study from the basaltic Auckland Volcanic Field, New Zealand

NASA Astrophysics Data System (ADS)

Hopkins, Jenni L.; Millet, Marc-Alban; Timm, Christian; Wilson, Colin J. N.; Leonard, Graham S.; Palin, J. Michael; Neil, Helen

2015-09-01

Probabilistic hazard forecasting for a volcanic region relies on understanding and reconstructing the eruptive record (derived potentially from proximal as well as distal volcanoes). Tephrostratigraphy is commonly used as a reconstructive tool by cross-correlating tephra deposits to create a stratigraphic framework that can be used to assess magnitude-frequency relationships for eruptive histories. When applied to widespread rhyolitic deposits, tephra identifications and correlations have been successful; however, the identification and correlation of basaltic tephras are more problematic. Here, using tephras in drill cores from six maars in the Auckland Volcanic Field (AVF), New Zealand, we show how X-ray density scanning coupled with magnetic susceptibility analysis can be used to accurately and reliably identify basaltic glass shard-bearing horizons in lacustrine sediments and which, when combined with the major and trace element signatures of the tephras, can be used to distinguish primary from reworked layers. After reliably identifying primary vs. reworked basaltic horizons within the cores, we detail an improved method for cross-core correlation based on stratigraphy and geochemical fingerprinting. We present major and trace element data for individual glass shards from 57 separate basaltic horizons identified within the cores. Our results suggest that in cases where major element compositions (SiO2, CaO, Al2O3, FeO, MgO) do not provide unambiguous correlations, trace elements (e.g. La, Gd, Yb, Zr, Nb, Nd) and trace element ratios (e.g. [La/Yb]N, [Gd/Yb]N, [Zr/Yb]N) are successful in improving the compositional distinction between the AVF basaltic tephra horizons, thereby allowing an improved eruptive history of the AVF to be reconstructed.

Assessment of subsurface chlorinated solvent contamination using tree cores at the front street site and a former dry cleaning facility at the Riverfront Superfund site, New Haven, Missouri, 1999-2003

USGS Publications Warehouse

Schumacher, John G.; Struckhoff, Garrett C.; Burken, Joel G.

2004-01-01

Tree-core sampling has been a reliable and inexpensive tool to quickly assess the presence of shallow (less than about 30 feet deep) tetrachloroethene (PCE) and trichloroethene (TCE) contamination in soils and ground water at the Riverfront Superfund Site. This report presents the results of tree-core sampling that was successfully used to determine the presence and extent of chlorinated solvent contamination at two sites, the Front Street site (operable unit OU1) and the former dry cleaning facility, that are part of the overall Riverfront Superfund Site. Traditional soil and ground-water sampling at these two sites later confirmed the results from the tree-core sampling. Results obtained from the tree-core sampling were used to design and focus subsequent soil and ground-water investigations, resulting in substantial savings in time and site assessment costs. The Front Street site is a small (less than 1-acre) site located on the Missouri River alluvium in downtown New Haven, Missouri, about 500 feet from the south bank of the Missouri River. Tree-core sampling detected the presence of subsurface PCE contamination at the Front Street site and beneath residential property downgradient from the site. Core samples from trees at the site contained PCE concentrations as large as 3,850 mg-h/kg (micrograms in headspace per kilogram of wet core) and TCE concentrations as large as 249 mg-h/kg. Soils at the Front Street site contained PCE concentrations as large as 6,200,000 mg/kg (micrograms per kilogram) and ground-water samples contained PCE concentrations as large as 11,000 mg/L (micrograms per liter). The former dry cleaning facility is located at the base of the upland that forms the south bank of the Missouri River alluvial valley. Tree-core sampling did not indicate the presence of PCE or TCE contamination at the former dry cleaning facility, a finding that was later confirmed by the analyses of soil samples collected from the site. The lateral extent of PCE

Space Station Environmental Control and Life Support System Test Facility at Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Springer, Darlene

1989-01-01

Different aspects of Space Station Environmental Control and Life Support System (ECLSS) testing are currently taking place at Marshall Space Flight Center (MSFC). Unique to this testing is the variety of test areas and the fact that all are located in one building. The north high bay of building 4755, the Core Module Integration Facility (CMIF), contains the following test areas: the Subsystem Test Area, the Comparative Test Area, the Process Material Management System (PMMS), the Core Module Simulator (CMS), the End-use Equipment Facility (EEF), and the Pre-development Operational System Test (POST) Area. This paper addresses the facility that supports these test areas and briefly describes the testing in each area. Future plans for the building and Space Station module configurations will also be discussed.

Hydrothermal alteration and diagenesis of terrestrial lacustrine pillow basalts: Coordination of hyperspectral imaging with laboratory measurements

NASA Astrophysics Data System (ADS)

Greenberger, Rebecca N.; Mustard, John F.; Cloutis, Edward A.; Mann, Paul; Wilson, Janette H.; Flemming, Roberta L.; Robertson, Kevin M.; Salvatore, Mark R.; Edwards, Christopher S.

2015-12-01

We investigate an outcrop of ∼187 Ma lacustrine pillow basalts of the Talcott Formation exposed in Meriden, Connecticut, USA, focusing on coordinated analyses of one pillow lava to characterize the aqueous history of these basalts in the Hartford Basin. This work uses a suite of multidisciplinary measurements, including hyperspectral imaging, other spectroscopic techniques, and chemical and mineralogical analyses, from the microscopic scale up to the scale of an outcrop. The phases identified in the sample are albite, large iron oxides, and titanite throughout; calcite in vesicles; calcic clinopyroxene, aegirine, and Fe/Mg-bearing clay in the rind; and fine-grained hematite and pyroxenes in the interior. Using imaging spectroscopy, the chemistry and mineralogy results extend to the hand sample and larger outcrop. From all of the analyses, we suggest that the pillow basalts were altered initially after emplacement, either by heated lake water or magmatic fluids, at temperatures of at least 400-600 °C, and the calcic clinopyroxenes and aegirine identified in the rind are a preserved record of that alteration. As the hydrothermal system cooled to slightly lower temperatures, clays formed in the rind, and, during this alteration, the sample oxidized to form hematite in the matrix of the interior and Fe3+ in the pyroxenes in the rind. During the waning stages of the hydrothermal system, calcite precipitated in vesicles within the rind. Later, diagenetic processes albitized the sample, with albite replacing plagioclase, lining vesicles, and accreting onto the exterior of the sample. This albitization or Na-metasomatism occurred when the lake within the Hartford Basin evaporated during a drier past climatic era, resulting in Na-rich brines. As Ca-rich plagioclase altered to albite, Ca was released into solution, eventually precipitating as calcite in previously-unfilled vesicles, dominantly in the interior of the pillow. Coordinated analyses of this sample permit

Crew Member Interface with Space Station Furnace Facility

NASA Technical Reports Server (NTRS)

Cash, Martha B.

1997-01-01

The Space Station Furnace Facility (SSFF) is a facility located in the International Space Station United States Laboratory (ISS US Lab) for materials research in the microgravity environment. The SSFF will accommodate basic research, commercial applications, and studies of phenomena of metals and alloys, electronic and photonic materials, and glasses and ceramics. To support this broad base of research requirements, the SSFF will operate, regulate, and support a variety of Experiment Modules (EMs). To meet station requirements concerning the microgravity level needed for experiments, station is providing an active vibration isolation system, and SSFF provides the interface. SSFF physically consists of a Core Rack and two instrument racks (IRs) that occupy three adjacent ISS US Lab rack locations within the International Space Station (ISS). All SSFF racks are modified International Standard Payload Racks (ISPR). SSFF racks will have a 50% larger pass through area on the lower sides than ISPRs to accommodate the many rack to rack interconnections. The Instrument Racks are further modified with lowered floors and an additional removable panel (15" x 22") on top of the rack for access if needed. The Core Rack shall contain all centralized Core subsystems and ISS subsystem equipment. The two Instrument Racks shall contain the distributed Core subsystem equipment, ISS subsystem equipment, and the EMs. The Core System, which includes the Core Rack, the IR structures, and subsystem components located in the IRs serves as the central control and management for the IRs and the EMs. The Core System receives the resources provided by the International Space Station (ISS) and modifies, allocates, and distributes these resources to meet the operational requirements of the furnace. The Core System is able to support a total of four EMs and can control, support, and activate/deactivate the operations of two EMs, simultaneously. The IRs can be configured to house two small EMs or

Proposed Design and Operation of a Heat Pipe Reactor using the Sandia National Laboratories Annular Core Test Facility and Existing UZrH Fuel Pins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, Steven A.; Lipinski, Ronald J.; Pandya, Tara

2005-02-06

Heat Pipe Reactors (HPR) for space power conversion systems offer a number of advantages not easily provided by other systems. They require no pumping, their design easily deals with freezing and thawing of the liquid metal, and they can provide substantial levels of redundancy. Nevertheless, no reactor has ever been operated and cooled with heat pipes, and the startup and other operational characteristics of these systems remain largely unknown. Signification deviations from normal reactor heat removal mechanisms exist, because the heat pipes have fundamental heat removal limits due to sonic flow issues at low temperatures. This paper proposes an earlymore » prototypic test of a Heat Pipe Reactor (using existing 20% enriched nuclear fuel pins) to determine the operational characteristics of the HPR. The proposed design is similar in design to the HOMER and SAFE-300 HPR designs (Elliot, Lipinski, and Poston, 2003; Houts, et. al, 2003). However, this reactor uses existing UZrH fuel pins that are coupled to potassium heat pipes modules. The prototype reactor would be located in the Sandia Annular Core Research Reactor Facility where the fuel pins currently reside. The proposed reactor would use the heat pipes to transport the heat from the UZrH fuel pins to a water pool above the core, and the heat transport to the water pool would be controlled by adjusting the pressure and gas type within a small annulus around each heat pipe. The reactor would operate as a self-critical assembly at power levels up to 200 kWth. Because the nuclear heated HPR test uses existing fuel and because it would be performed in an existing facility with the appropriate safety authorization basis, the test could be performed rapidly and inexpensively. This approach makes it possible to validate the operation of a HPR and also measure the feedback mechanisms for a typical HPR design. A test of this nature would be the world's first operating Heat Pipe Reactor. This reactor is therefore

The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons

NASA Astrophysics Data System (ADS)

Enzel, Yehouda; Kushnir, Yochanan; Quade, Jay

2015-06-01

A dramatic increase in regional summer rainfall amount has been proposed for the Arabian Peninsula during the middle Holocene (ca. 9-5 ka BP) based on lacustrine sediments, inferred lake levels, speleothems, and pollen. This rainfall increase is considered primarily the result of an intensified Indian summer monsoon as part of the insolation-driven, northward shift of the boreal summer position of the Inter-Tropical Convergence Zone (ITCZ) to over the deserts of North Africa, Arabia, and northwest India. We examine the basis for the proposed drastic climate change in Arabia and the shifts in the summer monsoon rains, by reviewing paleohydrologic lacustrine records from Arabia. We evaluate and reinterpret individual lake-basin status regarding their lacustrine-like deposits, physiography, shorelines, fauna and flora, and conclude that these basins were not occupied by lakes, but by shallow marsh environments. Rainfall increase required to support such restricted wetlands is much smaller than needed to form and maintain highly evaporating lakes and we suggest that rainfall changes occurred primarily at the elevated edges of southwestern, southern, and southeastern Arabian Peninsula. These relatively small changes in rainfall amounts and local are also supported by pollen and speleothems from the region. The changes do not require a northward shift of the Northern Hemisphere summer ITCZ and intensification of the Indian monsoon rainfall. We propose that (a) latitudinal and slight inland expansion of the North African summer monsoon rains across the Red Sea, and (b) uplifted moist air of this monsoon to southwestern Arabia highlands, rather than rains associated with intensification of Indian summer monsoon, as proposed before, increased rains in that region; these African monsoon rains produced the modest paleo-wetlands in downstream hyperarid basins. Furthermore, we postulate that as in present-day, the ITCZ in the Indian Ocean remained at or near the equator all

LUMA: A many-core, Fluid-Structure Interaction solver based on the Lattice-Boltzmann Method

NASA Astrophysics Data System (ADS)

Harwood, Adrian R. G.; O'Connor, Joseph; Sanchez Muñoz, Jonathan; Camps Santasmasas, Marta; Revell, Alistair J.

2018-01-01

The Lattice-Boltzmann Method at the University of Manchester (LUMA) project was commissioned to build a collaborative research environment in which researchers of all abilities can study fluid-structure interaction (FSI) problems in engineering applications from aerodynamics to medicine. It is built on the principles of accessibility, simplicity and flexibility. The LUMA software at the core of the project is a capable FSI solver with turbulence modelling and many-core scalability as well as a wealth of input/output and pre- and post-processing facilities. The software has been validated and several major releases benchmarked on supercomputing facilities internationally. The software architecture is modular and arranged logically using a minimal amount of object-orientation to maintain a simple and accessible software.

A facile single-step synthesis of ternary multicore magneto-plasmonic nanoparticles.

PubMed

Benelmekki, Maria; Bohra, Murtaza; Kim, Jeong-Hwan; Diaz, Rosa E; Vernieres, Jerome; Grammatikopoulos, Panagiotis; Sowwan, Mukhles

2014-04-07

We report a facile single-step synthesis of ternary hybrid nanoparticles (NPs) composed of multiple dumbbell-like iron-silver (FeAg) cores encapsulated by a silicon (Si) shell using a versatile co-sputter gas-condensation technique. In comparison to previously reported binary magneto-plasmonic NPs, the advantage conferred by a Si shell is to bind the multiple magneto-plasmonic (FeAg) cores together and prevent them from aggregation at the same time. Further, we demonstrate that the size of the NPs and number of cores in each NP can be modulated over a wide range by tuning the experimental parameters.

Open Core Data approaches to exposing facility data to support FAIR principles

NASA Astrophysics Data System (ADS)

Fils, D.; Lehnert, K.; Noren, A. J.

2017-12-01

The Open Core Data (OCD) award from NSF is focused on exposing scientific drilling data from the JOIDES Resolution Science Operator (JRSO) and Continental Scientific Drilling Coordination Office (CSDCO) following guidance from the Force 11 FAIR principles and the W3C "best practices" recommendations and notes. The goal of this implementation is to provide the identification, access, citation and provenance of these data to support the research community. OCD employs Linked Open Data (LOD) patterns and HTML5 microdata publishing via JSON-LD using various vocabularies. These vocabularies include schema.org, GeoLink and other relevant community vocabularies. Attention is paid to enabling hypermedia navigation between resources to aid in fast and efficient harvesting of the metadata directly from the LOD approach using web architecture patterns. Further, the vocabularies are employed to address the need of both DOI assignment and creation of data citation entries following ESIP data citation recommendations. The use of LOD, community vocabularies and persistent identifiers has enabled linking between hosted and remote data resources. In addition to the semantic metadata and LOD pattern, OCD is implementing approaches to data packaging to facilitate data use. OCD is currently using the CSV for the Web approach but is moving to implement frictionless data packages. This data package model provide access to a large suite of tools, libraries and workbenches to support data utilization, validation and visualization. Further, a basic reference implementation of the W3C PROV-AQ pingback pattern is under testing. This work is done in coordination with the RDA Provenance Patterns WG and follows patterns already employed by Geoscience Australia. This development is also done in coordination with ESIP provenance work. As needed, more traditional Application Program Interfaces (APIs) are exposed following best practices in RESTful services. All these capabilities are implemented

Lipid-based palaeotemperature reconstruction in lakes: New insights on the applicability of branched GDGTs in lacustrine sedimentary archives

NASA Astrophysics Data System (ADS)

Weber, Yuki; De Jonge, Cindy; Hopmans, Ellen C.; Sinninghe Damsté, Jaap S.; Gilli, Adrian; Lehmann, Moritz F.; Niemann, Helge

2014-05-01

Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that occur ubiquitously in soils worldwide. The relative abundances of nine structurally related brGDGTs (used in the MBT and CBT indices) have been shown to correlate with mean annual air temperature (MAAT) and soil pH, making them potential proxies in sediments that receive soil organic matter from terrestrial environments. The brGDGT distributions in lake deposits, however, mostly follow a different correlation with air temperature and (to a minor extent) lake water pH. This points to a substantial contribution of brGDGTs from in situ production within the lake water column and/or -sediments. It is also quite likely that the fractions of soil- and lake-derived brGDGTs vary considerably between sampling sites and with time, due to spatial and temporal changes in sediment input rates. Paleoclimate reconstructions using lacustrine brGDGT records thus remain challenging, especially because little is known about the environmental variables that control bacterial brGDGT production within aquatic environments. In order to decipher the impact of in situ production, we compared the brGDGT composition of surface sediments and corresponding catchment soils of 35 lakes from the Swiss alpine region, spanning an altitudinal gradient from 200 - 2000 m above mean sea level. We used an improved HPLC method to additionally quantify six recently discovered isomers, which vary in the position of their methyl branches. These 6-methyl compounds previously co-eluted with those brGDGTs used to calculate the MBT and CBT indices, obscuring any paleoenvironmental information they potentially yield. A principal component analysis suggests that the fractional abundances of the 6-methyl brGDGTs are primarily controlled by the surface water pH of the lakes. Notably, and in contrast to soils, the fractional abundance of the 5-methyl pentamethylated brGDGT in lake sediments does not show a correlation with

Is the closest facility the one actually used? An assessment of travel time estimation based on mammography facilities.

PubMed

Alford-Teaster, Jennifer; Lange, Jane M; Hubbard, Rebecca A; Lee, Christoph I; Haas, Jennifer S; Shi, Xun; Carlos, Heather A; Henderson, Louise; Hill, Deirdre; Tosteson, Anna N A; Onega, Tracy

2016-02-18

Characterizing geographic access depends on a broad range of methods available to researchers and the healthcare context to which the method is applied. Globally, travel time is one frequently used measure of geographic access with known limitations associated with data availability. Specifically, due to lack of available utilization data, many travel time studies assume that patients use the closest facility. To examine this assumption, an example using mammography screening data, which is considered a geographically abundant health care service in the United States, is explored. This work makes an important methodological contribution to measuring access--which is a critical component of health care planning and equity almost everywhere. We analyzed one mammogram from each of 646,553 women participating in the US based Breast Cancer Surveillance Consortium for years 2005-2012. We geocoded each record to street level address data in order to calculate travel time to the closest and to the actually used mammography facility. Travel time between the closest and the actual facility used was explored by woman-level and facility characteristics. Only 35% of women in the study population used their closest facility, but nearly three-quarters of women not using their closest facility used a facility within 5 min of the closest facility. Individuals that by-passed the closest facility tended to live in an urban core, within higher income neighborhoods, or in areas where the average travel times to work was longer. Those living in small towns or isolated rural areas had longer closer and actual median drive times. Since the majority of US women accessed a facility within a few minutes of their closest facility this suggests that distance to the closest facility may serve as an adequate proxy for utilization studies of geographically abundant services like mammography in areas where the transportation networks are well established.

Hydrothermal activity and its paleoecological implications in the latest Miocene to Middle Pleistocene lacustrine environments of the Baza Basin (Betic Cordillera, SE Spain)

NASA Astrophysics Data System (ADS)

García-Aguilar, José Manuel; Guerra-Merchán, Antonio; Serrano, Francisco; Palmqvist, Paul; Flores-Moya, Antonio; Martínez-Navarro, Bienvenido

2014-07-01

The continental sedimentary record of the Baza Basin (Guadix-Baza Depression, Betic Cordillera, SE Spain) shows six sedimentary units of lacustrine origin deposited from the latest Miocene to the Middle Pleistocene. Depending on the interval considered, the lacustrine deposits are mainly composed of marls, carbonates or gypsiferous evaporites, showing lithological, mineralogical and geochemical features (i.e., magnesium, strontium and sulfur contents, celestine deposits and travertine growths) that are evidence of intense, tectonically-induced hydrothermal activity. According to the high concentrations of strontium and sulfur as well as the abundance of travertines and magnesium clays, the supply of hot waters was greater during the Zanclean, the Gelasian and the Calabrian, as a result of tectonic activity. Hydrothermal activity has continued until the present time and is responsible of the hot springs that are nowadays active in the Guadix-Baza Depression. The paleoenvironmental consequences of these sublacustrine hot springs were that during some intervals the lakes maintained a relatively permanent water table, not subject to periodic desiccations in the dry season, and warmer temperatures throughout the year. This resulted in a high level of organic productivity, especially for the Calabrian, which allowed the development of a rich and well diversified mammalian community, similar to those of modern African savannas with tree patches. In this mild environment, the permanent water sheet favored the presence of drought intolerant megaherbivores such as the giant extinct hippo Hippopotamus antiquus. The high standing crop biomass of ungulates resulted in the availability of abundant carcasses for scavengers such as hyenas and hominins, which explains the very high densities of skeletal remains preserved in the sediments distributed along the lake surroundings.

From the North American Great Basin to the planet Mars: Taking Lacustrine Geomorphology into the 21st Century

NASA Astrophysics Data System (ADS)

Edgett, Kenneth S.; Parker, Timothy J.

1997-09-01

Introduction. The entire planet Mars is presently a desert more arid than any on Earth. The planet appears to have had more water in the past, and some of this water affected the surface geology and geomorphology by carving a variety of channels. Despite the evidence for running water in the martian past, the presence of sanding bodies of water (lakes, oceans) has been a topic of considerable controversy in the past two decades. The issue is still not settled, but evidence has mounted to suggest that lakes and oceans were indeed a major factor in shaping the present geomorphology of the martian surface. Although there remains uncertainty as to whether lakes were present on Mars, major efforts to seek evidence for fossil martian organisms are focused on the search for lake sediments and tufa deposits [1]. In 2001 and 2003, the NASA Mars Surveyor Program will launch mobile rovers designed to explore the surface and collect samples for return to Earth. The first set of samples will reach Earth in 2008. The types of landing sites being considered for the '01 and '03 missions include areas interpreted as ancient lacustrine deposits. Knowledge and experience with the geomorphology of lacustrine features in the North American Great Basin is crucial for identifying lake features on Mars. Martian Lakes and Oceans: Prior to spacecraft exploration of Mars, many early astronomers though that the low-albedo surfaces of Mars could be seas or lakes, others considered these to be vast tracts of vegetation [2]. The low-albedo surfaces are now known to be the result of aeolian action on the distribution of sand and dust. The Mariner 4, 6, and 7 spacecraft in 1965 and 1969 stunned the world by showing a cratered, lunar-like martian surface. In 1972, Mariner 9 showed a more Earth-like surface - indeed, there were numerous channels, some carved by massive floods, others perhaps by fluvial run-off or sapping. The Viking orbiters (1976-1980) provided additional images; these formed the

Study of an amorphous alloy core transformer

NASA Astrophysics Data System (ADS)

Nafalski, A.; Frost, D. C.

1994-05-01

Amorphous core transformers (ACT) have become a technological and commercial reality and there are an estimated 400,000 units installed worldwide [1]. Their applications reflect changes in buying practices, where the efficiency evaluation is an important factor in the purchasing decision for distribution transformers. Use of the total ownership cost (TOC) concept facilities the selection of a transformer on the basis of its performance. This concept is used in this paper to investigate the feasibility of applying a distribution ACT in Western Australian (WA). A 10 kVA ACT, evaluated by the TOC method, was compared with a traditional silicon iron core transformer of the same rating. The cost of amorphous metal (relative to alternative materials), the distribution load profile, and the values of capitalised loss costs are factors which affect the cost effectiveness of ACTs.

Core-Sheath Paraffin-Wax-Loaded Nanofibers by Electrospinning for Heat Storage.

PubMed

Lu, Yuan; Xiao, Xiudi; Zhan, Yongjun; Huan, Changmeng; Qi, Shuai; Cheng, Haoliang; Xu, Gang

2018-04-18

Paraffin wax (PW) is widely used for smart thermoregulation materials due to its good thermal performance. However, the leakage and low thermal conductivity of PW hinder its application in the heat storage field. Accordingly, developing effective methods to address these issues is of great importance. In this study, we explored a facile approach to obtain PW-loaded core-sheath structured flexible nanofibers films via coaxial electrospinning technique. The PW as the core layer was successfully encapsulated by the sheath-layer poly(methyl methacrylate). The diameter of the fiber core increased from 395 to 848 nm as the core solution speed rate increased from 0.1 to 0.5 mL/h. In addition, it can be seen that higher core solution speed rate could lead to higher PW encapsulation efficiency according to the transmission electron microscopy results. The core-sheath nanofiber films, moreover, possessed the highest latent heat of 58.25 J/g and solidifying enthalpy of -56.49 J/g. In addition, we found that after 200 thermal cycles, there was little change in latent heat, which demonstrated that it is beneficial for the PW-loaded core-sheath structure to overcome the leakage issue and enhance thermal stability properties for the thermoregulation film.

Giving perspective to cliff exposures with ground penetrating radar: Devonian lacustrine shore zone architecture

NASA Astrophysics Data System (ADS)

Andrews, Steven; Moreau, Julien; Archer, Stuart

2015-04-01

The orbitally-controlled cyclic lacustrine successions of the Middle Devonian in Northern Scotland contains repeated developments of shore zone sandstones. However, due to the cliff-forming nature of the succession and the attitude of the sections through these sandstones, interpretation of this facies has been problematic. To better understand the shore zone systems, we carried out very high resolution sedimentary logging and constructed photo-panels which were combined with high resolution GPR profiling (250 MHz). To ensure close ties between the sedimentary logs and the GPR data, the cliffs were accessed using rope access techniques while GPR grids were shot directly above. The profiles were shot mainly in the strike direction of what was thought to be the shore elongation every 5-10 m and every 20-30 m in the dip direction. Shore zone systems of 3 different sequences have been imaged for a total of 1155 m of GPR profile collected. This configuration has allowed 3D visualisation of the architecture of the shore zone systems and, in combination with detailed sedimentology, provided insights into the generation of the dynamic shore zone environments. The coastal cliffs of northern Scotland expose sedimentary cycles on average 16-m-thick which record deep lake, perennial lake and playa environments. The shore zone deposits reach 2 to 3.5 m in thickness. Loading and discrete channel forms are recognised in both the GPR data and sedimentary logs through the lower portion of the lake shore zone successions. Up-section the sandstone beds appear to become amalgamated forming subtle low angle accretionary bar complexes which although visible in outcrop, after careful investigation, can be fully visualised and examined in the GPR data. The 3D visualisation allowed mapping the architecture and distribution of the bars . The orientation of these features, recognised from the survey, is consistent with extensive palaeocurrent measurements from oscillation ripples. Further

Stratigraphy, sedimentology, and volume of sediments behind a dam relic on the Muskegon River, Big Rapids, Michigan

USGS Publications Warehouse

Westjohn, David B.

1997-01-01

The proposed removal of the remnants of a hydroelectric dam in the Muskegon River at Big Rapids, Michigan, will potentially affect flow of the river at the city's water intake system. Fifteen boreholes were augered in bottom sediments in the river just upstream from the dam relic, and streambottom profiles were made using ground-penetrating radar. Data from boreholes show that sediments captured by the dam foundation were deposited in two distinctly different sedimentary environments. Sediments that overlie the pre-dam channel surface consist of lacustrine clay, wood chips, silt, and sand. These lacustrine sediments are interbedded in a cyclical fashion, and they were deposited under low flow to stagnant water conditions during 1916-66, when a 17-foot-tall hydroelectric dam was in place. Demolition of the upper 13 feet of this dam in 1966 resulted in erosion of most of the lacustrine sediments, and subsequent deposition of coarser alluvium in the impoundment behind the remaining dam foundation. Lacustrine sediments are present in the active part of the stream channel and extend from the dam foundation to about 1,300 feet upstream. The composite thickness of lacustrine sediments and overlying coarser alluvium was determined from sediment cores collected from the boreholes. The volume of these sediments is estimated to be about 19,000 cubic yards.

Record of late Pleistocene glaciation and deglaciation in the southern Cascade Range. I. Petrological evidence from lacustrine sediment in Upper Klamath Lake, southern Oregon

USGS Publications Warehouse

Reynolds, R.L.; Rosenbaum, J.G.; Rapp, J.; Kerwin, M.W.; Bradbury, J.P.; Colman, S.; Adam, D.

2004-01-01

Petrological and textural properties of lacustrine sediments from Upper Klamath Lake, Oregon, reflect changing input volumes of glacial flour and thus reveal a detailed glacial history for the southern Cascade Range between about 37 and 15 ka. Magnetic properties vary as a result of mixing different amounts of the highly magnetic, glacially generated detritus with less magnetic, more weathered detritus derived from unglaciated parts of the large catchment. Evidence that the magnetic properties record glacial flour input is based mainly on the strong correlation between bulk sediment particle size and parameters that measure the magnetite content and magnetic mineral freshness. High magnetization corresponds to relatively fine particle size and lower magnetization to coarser particle size. This relation is not found in the Buck Lake core in a nearby, unglaciated catchment. Angular silt-sized volcanic rock fragments containing unaltered magnetite dominate the magnetic fraction in the late Pleistocene sediments but are absent in younger, low magnetization sediments. The finer grained, highly magnetic sediments contain high proportions of planktic diatoms indicative of cold, oligotrophic limnic conditions. Sediment with lower magnetite content contains populations of diatoms indicative of warmer, eutrophic limnic conditions. During the latter part of oxygen isotope stage 3 (about 37-25 ka), the magnetic properties record millennial-scale variations in glacial-flour content. The input of glacial flour was uniformly high during the Last Glacial Maximum, between about 21 and 16 ka. At about 16 ka, magnetite input, both absolute and relative to hematite, decreased abruptly, reflecting a rapid decline in glacially derived detritus. The decrease in magnetite transport into the lake preceded declines in pollen from both grass and sagebrush. A more gradual decrease in heavy mineral content over this interval records sediment starvation with the growth of marshes at the margins

Predictions and Tests of the "Late Noachian Icy Highlands" Climate Model: Can Evidence for Fluvial/Lacustrine Systems Be Reconciled?

NASA Astrophysics Data System (ADS)

Head, J. W., III

2016-12-01

Improved 3D global simulations (GCMs) of the early martian climate have found that for atmospheric pressures greater than a fraction of a bar, atmospheric-surface thermal coupling occurs and the adiabatic cooling effect (ACE) causes temperatures in the southern uplands to fall significantly below the global average. Long-term climate evolution simulations indicate that in these circumstances, water ice is transported to the highlands from low-lying regions for a wide range of obliquities. Conditions are too cold (MAT 225 K) to permit the presence of long-term surface liquid water, including streams, lakes and oceans. The LNIH equilibrium state predicts: 1) a global permafrost layer, 2) a horizontally stratified hydrological cycle/system, 3) thick ice deposits in the southern uplands, 4) an extended water ice cap on the southern pole, and 5) no rainfall, streams lakes or oceans. The majority of these predictions are in direct conflict with the observed fluvial/lacustrine geologic record. Can non-equilibrium conditions in a LNIH scenario explain these conflicts by transient heating and melting of the LNIH? As steps in the comprehensive testing of this "Late Noachian Icy Highlands" (LNIH) model we explore the predictions for geologic settings and processes in both equilibrium and non-equilibrium climate states. We assess the following sources of disequilibrium: 1) Top-down heating and melting: a) impact cratering, b) extrusive/explosive volcanism, and c) short-term emission of greenhouse gases. 2) Bottom up heating and melting: a) enhanced regional-global geothermal gradients, and b) thick ice accumulation to cause/sustain basal melting, wet-based glaciation and runoff. We assess these disequilibrium mechanisms in terms of: 1) the altitude dependence of melting, 2) melting duration, 3) volumes of meltwater produced, 4) predicted locations of meltwater production, and 6) comparison to the distribution of fluvial/lacustrine features. We find that the Late Noachian Icy

The NASA Glen Research Center's Hypersonic Tunnel Facility. Chapter 16

NASA Technical Reports Server (NTRS)

Woike, Mark R.; Willis, Brian P.

2001-01-01

The NASA Glenn Research Center's Hypersonic Tunnel Facility (HTF) is a blow-down, freejet wind tunnel that provides true enthalpy flight conditions for Mach numbers of 5, 6, and 7. The Hypersonic Tunnel Facility is unique due to its large scale and use of non-vitiated (clean air) flow. A 3MW graphite core storage heater is used to heat the test medium of gaseous nitrogen to the high stagnation temperatures required to produce true enthalpy conditions. Gaseous oxygen is mixed into the heated test flow to generate the true air simulation. The freejet test section is 1.07m (42 in.) in diameter and 4.3m (14 ft) in length. The facility is well suited for the testing of large scale airbreathing propulsion systems. In this chapter, a brief history and detailed description of the facility are presented along with a discussion of the facility's application towards hypersonic airbreathing propulsion testing.

Tephra and cryptotephra in a 60,000-year-old lacustrine sequence from the Fucino Basin: new insights into the major explosive events in Italy

NASA Astrophysics Data System (ADS)

Di Roberto, Alessio; Smedile, Alessandra; Del Carlo, Paola; De Martini, Paolo Marco; Iorio, Marina; Petrelli, Maurizio; Pantosti, Daniela; Pinzi, Stefania; Todrani, Alessandro

2018-03-01

Two cores were sampled in the Fucino Basin (central Apennines, Italy), which represents an extensional intramountain basin filled by Pliocene to Quaternary continental alluvial and lacustrine deposits. The cores were investigated for tephra content and five visible tephras with thickness ranging from 1 to 8 cm were identified. Six additional cryptotephra were identified during the inspection of significant peaks of the magnetic susceptibility curve. Texture and mineralogy of five tephra and six cryptotephra layers were analyzed by means of scanning electron microscope coupled with energy-dispersive X-ray spectrometry system (SEM-EDS) and geochemical measurements were performed by an electron microprobe (EPMA) equipped with five wavelength-dispersive spectrometers (WDS) and using a laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) system on single glass shards. The results allowed us to assign tephra and cryptotephra to ten known volcanic eruptions that occurred over the last ca. 60 ka in the Campanian Province (Phlegrean Fields and Ischia Island), the Alban Hills volcanic complex, and Lipari island. In particular, we recognized the deposits of the Monte Epomeo Green Tuff and the Piroclastiti di Catavola eruptions of Ischia, the pre-Campanian Ignimbrite Tlc, the Campanian Ignimbrite and the Neapolitan Yellow Tuff eruptions of the Phlegrean Fields, the Gabellotto-Fiume Bianco eruption of Lipari, and all the four explosive events belonging to the last cycle of volcanic activity of Albano maar (Albano 4-7). Deposits from five of these identified events (i.e., Piroclastiti di Catavola, Gabellotto-Fiume Bianco, Albano 5 and 6 eruptions, and Campanian Ignimbrite) were previously un-reported in the Fucino basin. These findings add new tephra layers to the list of possible tephrochronologic markers in the region and highlight that a comprehensive tephra record may be constructed when the study of cryptotephra layers is included. Moreover, results

Relationships among charcoal particles from modern lacustrine sediments and remotely sensed fire events

NASA Astrophysics Data System (ADS)

López-Pérez, M.; Correa-Metrio, A.

2013-05-01

Analysis of charcoal particles from lacustrine sediments is a useful tool to understand fire regimes through time, and their relationships with climate and vegetation. However, the extent of the relationship between charcoal particles and their origin in terms of the spatial and temporal extent of the fire events is poorly known in the tropics. Modern sediments were collected from lakes in the Yucatan Peninsula and Central Mexico, 51 and 22 lakes respectively, to analyze their charcoal concentration and its relationships with modern fire events. Number of modern fire events was derived from the public source Fire Information for Resource Management System (FIRMS) for concentric spatial rings that ranged from 1 to 30 km of radius. The association between charcoal and fires was evaluated through the construction of linear models to explain charcoal concentration as a function of the number of fires recorded. Additionally, charcoal particles were stratified according to size to determine the association between fire distance and charcoal size classes. The relationship between total charcoal concentration and fire events was stronger for central Mexico than for the Yucatan Peninsula, which is probably the result of differences in vegetation cover. The highest determination coefficients were obtained for charcoal particle sizes ranging between 0.2 and 0.8 mm2, and for fire event distances of between 0 and 15 km from the lake. Overall, the analyses presented here offer useful tools to quantitatively and spatially reconstruct past regional fire dynamics in Central Mexico and the Yucatan Peninsula.

Process interpretation of laminated lacustrine sediments from the valley of the river Alf, Quaternary West Eifel Volcanic Field, Germany

NASA Astrophysics Data System (ADS)

Eichhorn, Luise; Pirrung, Michael; Zolitschka, Bernd; Büchel, Georg

2016-04-01

High-resolution annually laminated sediment archives from lakes Holzmaar and Meerfelder Maar located in the Quaternary West Eifel Volcanic Field are in the focus of many investigations (e.g. Brauer et al. 2001, Zolitschka 1991). These publications are related to predominantly biogenic varves covering the last ca. 14 ka years, i.e. the Lateglacial and the Holocene. In our study, laminated sediments consisting of clay-silt couplets are presented from paleolake Alf. This paleolake formed in a valley dammed by volcanic products, and covers the Pleniglacial between 31 and 24 ka BP (Pirrung et al. 2007). The focus of our study is the characterization of the structure of clay-silt couplets and the determination of their origin. The applied granulometry revealed mean grain sizes of 10 μm for the light laminae (colors refer to core scan photo) and 14 μm for the dark laminae (both middle silt). X-ray diffraction confirms identical mineral phases for light and dark laminae, with light laminae being clay-enriched containing a higher amount of sericite and chlorite while dark laminae are enriched in quartz. X-ray fluorescence and detrital microfacies analysis on thin sections indicate that calcite dominates in the dark laminae. Microscopically, three different types of silt layers are present. Type I are laminae with homogeneous sublayers, Type II are graded laminae and Type III are laminae with graded sublayers. Processes causing the formation of these silt lamination types can be attributed to repeatedly occurring snow melting, permafrost thawing or rain events linked with sediment delivery from the catchment into the lake. The amount of precipitation and melt water, sediment discharge and density stratification lead to gravity suspension fall out, partial erosion of previously deposited unconsolidated sediments and resuspension in the lake. Brauer, A., et al. (2001). Lateglacial varve chronology and biostratigraphy of lakes Holzmaar and Meerfelder Maar, Germany. Boreas 30

Late Glacial and Holocene Climate Change in the subantarctic Auckland Islands

NASA Astrophysics Data System (ADS)

Gilmer, G.; Moy, C. M.; Vandergoes, M.; Gadd, P.; Riesselman, C. R.; Jacobsen, G. E.; Wilson, G. S.; Visinand, C.

2017-12-01

Situated within the core of the Southern Hemisphere westerly winds, and between the subtropical and subantarctic fronts, the New Zealand subantarctic islands are uniquely positioned to evaluate past ocean and atmospheric change in the middle to high southern latitudes. We collected a series of sediment cores from Auckland Island fjords to produce a high-resolution record of climate change following the Last Glacial Maximum. Physical property and organic geochemical data, Itrax XRF, and visual core descriptions indicate the cores capture several phases of sedimentation. From these studies, we identify four primary sedimentary facies: 1) a deglacial facies exhibiting mm-scale laminae defined by magnetic susceptibility and density contrasts and high counts of elements associated with terrigenous sources; 2) a lacustrine facies defined by very low density, high organic carbon concentrations and low counts of lithophilic elements; 3) a marine transgression facies with moderate density, moderate bioturbation and alternating marine and lacustrine sedimentary components; 4) a marine facies that contains biogenic carbonate. Radiocarbon results indicate deglacial sedimentation was underway in the basin by approximately 19,000 cal yr BP. Lacustrine deposition in ice-free conditions began around 15,600 cal yr BP and continued until marine transgression at approximately 9,500 cal yr BP. During the early Holocene between 11 and 9.5 ka, we observe elevated n-alkane δD values and an overall increase in redox-sensitive elements that signal a combination of warmer atmospheric temperatures and reduced westerly wind strength that drives fjord stratification. Poleward-shifted westerlies south of the Auckland Islands could accommodate these results, but there are few records to corroborate this interpretation. We will discuss these results within the context of developing New Zealand and subantarctic paleoclimate records in order to provide a more comprehensive record of past change.

TREAT Transient Analysis Benchmarking for the HEU Core

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kontogeorgakos, D. C.; Connaway, H. M.; Wright, A. E.

2014-05-01

This work was performed to support the feasibility study on the potential conversion of the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory from the use of high enriched uranium (HEU) fuel to the use of low enriched uranium (LEU) fuel. The analyses were performed by the GTRI Reactor Conversion staff at the Argonne National Laboratory (ANL). The objective of this study was to benchmark the transient calculations against temperature-limited transients performed in the final operating HEU TREAT core configuration. The MCNP code was used to evaluate steady-state neutronics behavior, and the point kinetics code TREKIN was used tomore » determine core power and energy during transients. The first part of the benchmarking process was to calculate with MCNP all the neutronic parameters required by TREKIN to simulate the transients: the transient rod-bank worth, the prompt neutron generation lifetime, the temperature reactivity feedback as a function of total core energy, and the core-average temperature and peak temperature as a functions of total core energy. The results of these calculations were compared against measurements or against reported values as documented in the available TREAT reports. The heating of the fuel was simulated as an adiabatic process. The reported values were extracted from ANL reports, intra-laboratory memos and experiment logsheets and in some cases it was not clear if the values were based on measurements, on calculations or a combination of both. Therefore, it was decided to use the term “reported” values when referring to such data. The methods and results from the HEU core transient analyses will be used for the potential LEU core configurations to predict the converted (LEU) core’s performance.« less

TRAC-PD2 posttest analysis of CCTF Test C1-16 (Run 025). [Cylindrical Core Test Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugimoto, J.

The TRAC-PD2 code version was used to analyze CCTF Test C1-16 (Run 025). The results indicate that the core heater rod temperatures, the liquid mass in the vessel, and differential pressures in the primary loop are predicted well, but the void fraction distribution in the core and water accumulation in the upper plenum are not in good agreement with the data.

Molecular biomarkers for sources of organic matter in lacustrine sediments in a subtropical lake in China.

PubMed

Wang, Yan-Hua; Yang, Hao; Chen, Xia; Zhang, Ji-Xiang; Ou, Jie; Xie, Biao; Huang, Chang-Chun

2013-05-01

N-alkanes distributions and stable isotopic compositions (δ(13)C and δ(15)N) in the lacustrine sediments of Shijiu lake were measured to assess whether biological source information was recorded in the molecular biomarker. Results showed regular unimodal n-alkanes distribution in range of C16-C33 with strong predominance of odd-numbered n-alkanes, maximizing at C29. The δ(15)N for SON were uniformly low, ranging from -6.7‰ to 3.8‰ and C/N ratios ranged from 6.6 to 10.0, suggesting that most of organic matter was influenced by terrestrial characteristics of the watershed. The δ(13)C for C27 to C31n-alkanes and for SOC varied from -32.9‰ to -26.6‰ and -23.4‰ to -21.6‰, respectively, falling within the range of corresponding n-alkanes in leaves mainly from C3 land plants. The values of C/N, CPI, OEP, ACL and C27/C31 exhibit similar temporal changes with the primary production, showing enhanced eutrophication resulted from increased anthropogenic activities in Shijiu lake from 1852 to 2010. Copyright © 2013 Elsevier Ltd. All rights reserved.

Systems Check: Community Colleges Turn to Facilities Assessments to Plan Capital Projects and Avoid Expensive Emergency Repairs

ERIC Educational Resources Information Center

Joch, Alan

2014-01-01

With an emphasis on planning and cutting costs to make better use of resources, facilities managers at community colleges across the nation have undertaken facilities audits usually with the help of outside engineers. Such assessments analyze the history and structural integrity of buildings and core components on campus, including heating…

The Core and Seasonal Microbiota of Raw Bovine Milk in Tanker Trucks and the Impact of Transfer to a Milk Processing Facility

PubMed Central

Kable, Mary E.; Srisengfa, Yanin; Laird, Miles; Zaragoza, Jose; McLeod, Jeremy; Heidenreich, Jessie

2016-01-01

ABSTRACT Currently, the bacterial composition of raw milk in tanker trucks and the outcomes of transfer and storage of that milk at commercial processing facilities are not well understood. We set out to identify the bacteria in raw milk collected for large-scale dairy product manufacturing. Raw bovine milk samples from 899 tanker trucks arriving at two dairy processors in San Joaquin Valley of California during three seasons (spring, summer, and fall) were analyzed by community 16S rRNA gene sequencing. This analysis revealed highly diverse bacterial populations, which exhibited seasonal differences. Raw milk collected in the spring contained the most diverse bacterial communities, with the highest total cell numbers and highest proportions being those of Actinobacteria. Even with this complexity, a core microbiota was present, consisting of 29 taxonomic groups and high proportions of Streptococcus and Staphylococcus and unidentified members of Clostridiales. Milk samples were also collected from five large-volume silos and from 13 to 25 tankers whose contents were unloaded into each of them during 2 days in the summer. Transfer of the milk to storage silos resulted in two community types. One group of silos contained a high proportion of Streptococcus spp. and was similar in that respect to the tankers that filled them. The community found in the other group of silos was distinct and dominated by Acinetobacter. Overall, despite highly diverse tanker milk community structures, distinct milk bacterial communities were selected within the processing facility environment. This knowledge can inform the development of new sanitation procedures and process controls to ensure the consistent production of safe and high-quality dairy products on a global scale. PMID:27555305

Spent Fuel Test-Climax: core logging for site investigation and instrumentation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilder, D.G.; Yow, J.L. Jr.; Thorpe, R.K.

1982-05-28

As an integral part of the Spent Fuel Test-Climax 5150 ft (1570 m) of granite core was obtained. This core was diamond drilled in various sizes, mainly 38-mm and 76-mm diameters. The core was teken with single tube core barrels and was unoriented. Techniques used to drill and log this core are discussed, as well as techniques to orient the core. Of the 5150 ft (1570 m) of core more than 3645 ft (1111 m) was retained and logged in some detail. As a result of the core logging, geologic discontinuities were identified, joint frequency and spacing characterized. Discontinuities identifiedmore » included several joint sets, shear zones and faults. Correlations based on coring along were generally found to be impossible, even for the more prominent features. The only feature properly correlated from the exploratory drilling was the fault system at the end of the facility, but it was not identified from the exploratory core as a fault. Identification of discontinuities was later helped by underground mapping that identified several different joint sets with different characteristics. It was found that joint frequency varied from 0.3 to 1.1 joint per foot of core for open fractures and from 0.3 to 3.3/ft for closed or healed fractures. Histograms of fracture spacing indicate that there is likely a random distribution of spacing superimposed upon uniformly spaced fractures. It was found that a low angle joint set had a persistent mean orientation. These joints were healed and had pervasive wall rock alteration which made identification of joints in this set possible. The recognition of a joint set with known attitude allowed orientation of much of the core. This orientation technique was found to be effective. 10 references, 25 figures, 4 tables.« less

Testing the Late Noachian Icy Highlands Model: Geological Observations, Processes and Origin of Fluvial and Lacustrine Features.

NASA Astrophysics Data System (ADS)

Head, James; Wordsworth, Robin; Forget, Francis; Madeleine, Jean-Baptiste; Halvey, Italy

2014-05-01

A new reconstruction of the Late Noachian Mars atmosphere and climate shows atmosphere-surface thermal coupling and an adiabatic cooling effect producing preferential distribution of snow and ice in the highlands. In this Late Noachian Icy Highlands (LNIH) scenario, snow and ice accumulate in the south circumpolar region and in the higher altitudes of the southern uplands, but the mean annual temperature is everywhere below freezing. How can the abundant evidence for water-related fluvial and lacustrine activity (valley networks, VN; open-basin lakes, OBL; closed-basin lakes; CBL) be reconciled with the icy highlands model? We investigate the nature of geologic processes operating in the icy highlands and use the Antarctic McMurdo Dry Valleys (MDV) as guidance in understanding and assessing how melting might be taking place. In the MDV, mean annual temperatures (MAT) are well below freezing. This results in a thick regional permafrost layer, the presence of an ice-table at shallow depths, and an overlying dry active layer. This configuration produces a perched aquifer and a horizontally stratified hydrologic system, where any melting results in local saturation of the dry active layer and channelized flow on top of the ice table. Top-down melting results in the dominance of lateral water transport, in contrast to temperate climates with vertical infiltration and transport to the groundwater table. Despite subzero MAT, MDV peak seasonal and peak daytime temperatures can exceed 273K and have a strong influence on the melting of available water ice. We present maps of the predicted distribution of LNIH snow and ice, compare these to the distribution of VN, OBL and CBL, and assess how top-down and bottom-up melting processes might explain the formation of these features in an otherwise cold and icy LN Mars. We assess the global near-surface water budget, analyze thickness estimates to distinguish areas of cold-based and wet-based glaciation, analyze the state of the

Magnetostratigraphy of The Astronomically-forced Alluvial Fan To Lacustrine Sequences of The Teruel Basin (late Miocene, Spain)

NASA Astrophysics Data System (ADS)

van Dam, J.; Aziz, H. Abdul; Hilgen, F. J.; Krijgsman, W.

During the last years, more and more examples of allocyclic, astronomical forced variations in the continental record have been documented. Sedimentary hiatuses, tra- ditionally regarded as the primary reason for the absence of clear patterns of orbital signature in the terrestrial domain, may be absent or short, given the appropriate set- ting. Spanish endoreic basins, for instance, form a ideal setting for the registration of orbital-forced climate change, as has been demonstrated for the Middle Miocene distal-alluvial fan-floodplain to lacustrine deposits of the Calatayud Basin. Astronom- ical forcing of sedimentary cycles has also been demonstrated in the Late Miocene distal alluvial fan to lacustrine sequences of the Teruel Basin. The early Late Miocene Cascante and Cañizar sections South of the town of Teruel show distinct cyclic bed- ding of red and/or green mottled mudstones alternating with white carbonate beds, whereby the alternation is mainly controlled by precession and eccentricity. The car- bonate beds are interpreted as (shallow) lake highstands, which occur in response to submergence of the alluvial fan distal plain. Small mammal teeth have been recov- ered from organic-richer layers at the base of the carbonate cycles in the Cascante and Cañizar sections. The recovery of mammal remains in terrestrial Milankovitch forced settings is crucial for several reasons: 1) it provides a first approximate age estimation for the sequence, thereby constraining other sources of temporal information such as magnetostratigraphy; 2) it infers very accurate ages of the mammal localities after as- tronomical tuning of the cyclic patterns; 3) it formulates hypotheses on the climatic regime and its variability using precise correlations to the insolation curve and in- terpretation of phase relations; and 4) it confronts the astronomically-based climatic reconstruction with the paleoecological reconstructions and faunal changes observed in the mammals themselves

First identification and characterization of Borrobol‐type tephra in the Greenland ice cores: new deposits and improved age estimates

PubMed Central

Davies, Siwan M.; Guðmundsdóttir, Esther R.; Abbott, Peter M.; Pearce, Nicholas J. G.

2018-01-01

ABSTRACT Contiguous sampling of ice spanning key intervals of the deglaciation from the Greenland ice cores of NGRIP, GRIP and NEEM has revealed three new silicic cryptotephra deposits that are geochemically similar to the well‐known Borrobol Tephra (BT). The BT is complex and confounded by the younger closely timed and compositionally similar Penifiler Tephra (PT). Two of the deposits found in the ice are in Greenland Interstadial 1e (GI‐1e) and an older deposit is found in Greenland Stadial 2.1 (GS‐2.1). Until now, the BT was confined to GI‐1‐equivalent lacustrine sequences in the British Isles, Sweden and Germany, and our discovery in Greenland ice extends its distribution and geochemical composition. However, the two cryptotephras that fall within GI‐1e ice cannot be separated on the basis of geochemistry and are dated to 14358 ± 177 a b2k and 14252 ± 173 a b2k, just 106 ± 3 years apart. The older deposit is consistent with BT age estimates derived from Scottish sites, while the younger deposit overlaps with both BT and PT age estimates. We suggest that either the BT in Northern European terrestrial sequences represents an amalgamation of tephra from both of the GI‐1e events identified in the ice‐cores or that it relates to just one of the ice‐core events. A firm correlation cannot be established at present due to their strong geochemical similarities. The older tephra horizon, found within all three ice‐cores and dated to 17326 ± 319 a b2k, can be correlated to a known layer within marine sediment cores from the North Iceland Shelf (ca. 17179‐16754 cal a BP). Despite showing similarities to the BT, this deposit can be distinguished on the basis of lower CaO and TiO2 and is a valuable new tie‐point that could eventually be used in high‐resolution marine records to compare the climate signals from the ocean and atmosphere. PMID:29576671

Core Hunter 3: flexible core subset selection.

PubMed

De Beukelaer, Herman; Davenport, Guy F; Fack, Veerle

2018-05-31

Core collections provide genebank curators and plant breeders a way to reduce size of their collections and populations, while minimizing impact on genetic diversity and allele frequency. Many methods have been proposed to generate core collections, often using distance metrics to quantify the similarity of two accessions, based on genetic marker data or phenotypic traits. Core Hunter is a multi-purpose core subset selection tool that uses local search algorithms to generate subsets relying on one or more metrics, including several distance metrics and allelic richness. In version 3 of Core Hunter (CH3) we have incorporated two new, improved methods for summarizing distances to quantify diversity or representativeness of the core collection. A comparison of CH3 and Core Hunter 2 (CH2) showed that these new metrics can be effectively optimized with less complex algorithms, as compared to those used in CH2. CH3 is more effective at maximizing the improved diversity metric than CH2, still ensures a high average and minimum distance, and is faster for large datasets. Using CH3, a simple stochastic hill-climber is able to find highly diverse core collections, and the more advanced parallel tempering algorithm further increases the quality of the core and further reduces variability across independent samples. We also evaluate the ability of CH3 to simultaneously maximize diversity, and either representativeness or allelic richness, and compare the results with those of the GDOpt and SimEli methods. CH3 can sample equally representative cores as GDOpt, which was specifically designed for this purpose, and is able to construct cores that are simultaneously more diverse, and either are more representative or have higher allelic richness, than those obtained by SimEli. In version 3, Core Hunter has been updated to include two new core subset selection metrics that construct cores for representativeness or diversity, with improved performance. It combines and outperforms the

Wind influence on the course of sedimentation processes of the laminated lacustrine sediments of Lake Czechowskie

NASA Astrophysics Data System (ADS)

Wiśniewska, Daria; Kramkowski, Mateusz; Tyszkowski, Sebastian

2016-04-01

The studies of the laminated lacustrine sediments play a very important role in the analysis of climate change. They provide valuable information related to the response of the ecosystem to changes in the environment. The condition for the development of the annual lamination is calm sedimentation, which can be compromised by the movement of water caused by waving. The depth to which this movement affects depends on the shape of the lake basin as well as the velocity and direction of the wind. During the study of sedimentary processes of laminated deposits in Lake Czechowskie (Tuchola Forest, North Poland, 53°52'N, 18°14' E, 108 m asl), the following question arose: How strong was the influence of the wind on the processes of lacustrine sedimentation? The key in getting the answers was the use of GIS techniques. Lake Czechowskie has an area of 76.6 hectares; it has two deeps separated by a threshold: a deeper one of 33 m (maximum depth of the basin) in the central-eastern part, and a shallower of 13 m in the western part. The speed of movement of water that is able to move sediment from the bottom of the lake, called the orbital wave velocity, is the basis for the designation of areas where re-suspension takes place. To calculate the wave parameters, the process of mixing, as well as the designation of re-suspension zones, the tool-script Wave Model (Rohweder et al. 2008) in the program ArsGIS 10.1 was used. The input data were wind direction and velocity from the meteorological station of Wirty about 15 km away, bathymetric data from acoustic profiling, and the Maximum Orbital Wave Velocity. The elements taken into account include maximum wind velocity of the multi-year 1996-2013, with particular emphasis on hurricanes Ksawery (December 2013) and Yoda (November 2011), during which wind velocity exceeded 120 km/h. In addition, maximum wind velocity ever recorded in the Polish Lowlands was considered. On the basis of the modelling, the authors delimited the areas

Humidity effects on soluble core mechanical and thermal properties (polyvinyl alcohol/microballoon composite) type CG extendospheres, volume 2

NASA Technical Reports Server (NTRS)

1993-01-01

This document constitutes the final report for the study of humidity effects and loading rate on soluble core (PVA/MB composite material) mechanical and thermal properties under Contract No. 100345. This report describes test results procedures employed, and any unusual occurrences or specific observations associated with this test program. The primary objective of this work was to determine if cured soluble core filler material regains its tensile and compressive strength after exposure to high humidity conditions and following a drying cycle. Secondary objectives include measurements of tensile and compressive modulus, and Poisson's ratio, and coefficient of thermal expansion (CTE) for various moisture exposure states. A third objective was to compare the mechanical and thermal properties of the composite using 'SG' and 'CG' type extendospheres. The proposed facility for the manufacture of soluble cores at the Yellow Creek site incorporates no capability for the control of humidity. Recent physical property tests performed with the soluble core filler material showed that prolonged exposure to high humidity significantly degradates in strength. The purpose of these tests is to determine if the product, process or facility designs require modification to avoid imparting a high risk condition to the ASRM.

Design and characterization of an irradiation facility with real-time monitoring

NASA Astrophysics Data System (ADS)

Braisted, Jonathan David

Radiation causes performance degradation in electronics by inducing atomic displacements and ionizations. While radiation hardened components are available, non-radiation hardened electronics can be preferable because they are generally more compact, require less power, and less expensive than radiation tolerant equivalents. It is therefore important to characterize the performance of electronics, both hardened and non-hardened, to prevent costly system or mission failures. Radiation effects tests for electronics generally involve a handful of step irradiations, leading to poorly-resolved data. Step irradiations also introduce uncertainties in electrical measurements due to temperature annealing effects. This effect may be intensified if the time between exposure and measurement is significant. Induced activity in test samples also complicates data collection of step irradiated test samples. The University of Texas at Austin operates a 1.1 MW Mark II TRIGA research reactor. An in-core irradiation facility for radiation effects testing with a real-time monitoring capability has been designed for the UT TRIGA reactor. The facility is larger than any currently available non-central location in a TRIGA, supporting testing of larger electronic components as well as other in-core irradiation applications requiring significant volume such as isotope production or neutron transmutation doping of silicon. This dissertation describes the design and testing of the large in-core irradiation facility and the experimental campaign developed to test the real-time monitoring capability. This irradiation campaign was performed to test the real-time monitoring capability at various reactor power levels. The device chosen for characterization was the 4N25 general-purpose optocoupler. The current transfer ratio, which is an important electrical parameter for optocouplers, was calculated as a function of neutron fluence and gamma dose from the real-time voltage measurements. The

Larger earthquakes recur more periodically: New insights in the megathrust earthquake cycle from lacustrine turbidite records in south-central Chile

NASA Astrophysics Data System (ADS)

Moernaut, J.; Van Daele, M.; Fontijn, K.; Heirman, K.; Kempf, P.; Pino, M.; Valdebenito, G.; Urrutia, R.; Strasser, M.; De Batist, M.

2018-01-01

Historical and paleoseismic records in south-central Chile indicate that giant earthquakes on the subduction megathrust - such as in AD1960 (Mw 9.5) - reoccur on average every ∼300 yr. Based on geodetic calculations of the interseismic moment accumulation since AD1960, it was postulated that the area already has the potential for a Mw 8 earthquake. However, to estimate the probability of such a great earthquake to take place in the short term, one needs to frame this hypothesis within the long-term recurrence pattern of megathrust earthquakes in south-central Chile. Here we present two long lacustrine records, comprising up to 35 earthquake-triggered turbidites over the last 4800 yr. Calibration of turbidite extent with historical earthquake intensity reveals a different macroseismic intensity threshold (≥VII1/2 vs. ≥VI1/2) for the generation of turbidites at the coring sites. The strongest earthquakes (≥VII1/2) have longer recurrence intervals (292 ±93 yrs) than earthquakes with intensity of ≥VI1/2 (139 ± 69yr). Moreover, distribution fitting and the coefficient of variation (CoV) of inter-event times indicate that the stronger earthquakes recur in a more periodic way (CoV: 0.32 vs. 0.5). Regional correlation of our multi-threshold shaking records with coastal paleoseismic data of complementary nature (tsunami, coseismic subsidence) suggests that the intensity ≥VII1/2 events repeatedly ruptured the same part of the megathrust over a distance of at least ∼300 km and can be assigned to Mw ≥ 8.6. We hypothesize that a zone of high plate locking - identified by geodetic studies and large slip in AD 1960 - acts as a dominant regional asperity, on which elastic strain builds up over several centuries and mostly gets released in quasi-periodic great and giant earthquakes. Our paleo-records indicate that Poissonian recurrence models are inadequate to describe large megathrust earthquake recurrence in south-central Chile. Moreover, they show an enhanced

Core-to-core uniformity improvement in multi-core fiber Bragg gratings

NASA Astrophysics Data System (ADS)

Lindley, Emma; Min, Seong-Sik; Leon-Saval, Sergio; Cvetojevic, Nick; Jovanovic, Nemanja; Bland-Hawthorn, Joss; Lawrence, Jon; Gris-Sanchez, Itandehui; Birks, Tim; Haynes, Roger; Haynes, Dionne

2014-07-01

Multi-core fiber Bragg gratings (MCFBGs) will be a valuable tool not only in communications but also various astronomical, sensing and industry applications. In this paper we address some of the technical challenges of fabricating effective multi-core gratings by simulating improvements to the writing method. These methods allow a system designed for inscribing single-core fibers to cope with MCFBG fabrication with only minor, passive changes to the writing process. Using a capillary tube that was polished on one side, the field entering the fiber was flattened which improved the coverage and uniformity of all cores.

Sanford Underground Research Facility - The United State's Deep Underground Research Facility

NASA Astrophysics Data System (ADS)

Vardiman, D.

2012-12-01

The 2.5 km deep Sanford Underground Research Facility (SURF) is managed by the South Dakota Science and Technology Authority (SDSTA) at the former Homestake Mine site in Lead, South Dakota. The US Department of Energy currently supports the development of the facility using a phased approach for underground deployment of experiments as they obtain an advanced design stage. The geology of the Sanford Laboratory site has been studied during the 125 years of operations at the Homestake Mine and more recently as part of the preliminary geotechnical site investigations for the NSF's Deep Underground Science and Engineering Laboratory project. The overall geology at DUSEL is a well-defined stratigraphic sequence of schist and phyllites. The three major Proterozoic units encountered in the underground consist of interbedded schist, metasediments, and amphibolite schist which are crosscut by Tertiary rhyolite dikes. Preliminary geotechnical site investigations included drift mapping, borehole drilling, borehole televiewing, in-situ stress analysis, laboratory analysis of core, mapping and laser scanning of new excavations, modeling and analysis of all geotechnical information. The investigation was focused upon the determination if the proposed site rock mass could support the world's largest (66 meter diameter) deep underground excavation. While the DUSEL project has subsequently been significantly modified, these data are still available to provide a baseline of the ground conditions which may be judiciously extrapolated throughout the entire Proterozoic rock assemblage for future excavations. Recommendations for facility instrumentation and monitoring were included in the preliminary design of the DUSEL project design and include; single and multiple point extensometers, tape extensometers and convergence measurements (pins), load cells and pressure cells, smart cables, inclinometers/Tiltmeters, Piezometers, thermistors, seismographs and accelerometers, scanners (laser

Nonlinear seismic analysis of a reactor structure impact between core components

NASA Technical Reports Server (NTRS)

Hill, R. G.

1975-01-01

The seismic analysis of the FFTF-PIOTA (Fast Flux Test Facility-Postirradiation Open Test Assembly), subjected to a horizontal DBE (Design Base Earthquake) is presented. The PIOTA is the first in a set of open test assemblies to be designed for the FFTF. Employing the direct method of transient analysis, the governing differential equations describing the motion of the system are set up directly and are implicitly integrated numerically in time. A simple lumped-nass beam model of the FFTF which includes small clearances between core components is used as a "driver" for a fine mesh model of the PIOTA. The nonlinear forces due to the impact of the core components and their effect on the PIOTA are computed.

Paleoenvironmental change as seen from a multiproxy perspective in the West Turkana Kaitio core (WTK13), Kenya

NASA Astrophysics Data System (ADS)

Beck, C. C.; Feibel, C. S.; Lupien, R.; Yost, C. L.; Rucina, S.; Russell, J. M.; Deino, A. L.; Sier, M.; Cohen, A. S.; Campisano, C. J.

2017-12-01

The Hominin Sites and Paleolakes Drilling Project's (HSPDP) primary goal is to provide high quality environmental records to test whether and how Earth system dynamics influenced the evolution of hominins in Africa. To this end, multiproxy records from individual basins are essential to understanding how paleoenvironments changed in relation to shifts in the climatic and/or tectonic regimes both locally on a basin-scale and regionally across East Africa. Because of its rich combination of paleoanthropologic and geologic data, the West Turkana Kaitio (WTK13) core is an important component of this synthesis. Using a combination of tephra chronology and paleomagnetic data, the core has been dated to 1.87-1.37 Ma. The sedimentology records deposition on a dynamic lacustrine margin becoming more influenced by channel and floodplain processes through time. Multiproxy records provide a window into paleoevironments of the Turkana Basin that operated on shorter time scales than this dominant first-order facies shift. Processional cycles (21 kyr) are picked up by indicator records where the preservation of the archive was good enough to allow for high-resolution analysis. However, interestingly, the biomarker record suggests that the hydroclimate of the Turkana Basin, while highly variable at the Milankovitch-scale, exhibits no directional trend in the mean values towards wetter or drier conditions. The combined phytolith and pollen records suggest that grasses, albeit with fluctuating abundances of C4 mesophytic and C4 xerophytic taxa, dominated the landscape throughout most of the core. This indicates that despite climatic variability, resource availability may have maintained some general consistency for hominins in the area. Ultimately, the time period spanned by the WTK13 record is significant for our understanding of hominin evolution as it covers an interval of increasing aridity on the African continent as observed in distal marine records. This synthesis

Liquefaction features interpreted as seismites in the Pleistocene fluvio-lacustrine deposits of the Neuquén Basin (Northern Patagonia)

NASA Astrophysics Data System (ADS)

Moretti, M.; Ronchi, A.

2011-04-01

Superbly exposed soft-sediment deformation structures in Pleistocene fluvio-lacustrine deposits along the southern border of the depression area called Bajo de Añelo (Departamento de Añelo, Neuquén Basin) have been analysed. In the study area, five stratigraphic sections were measured in detail: facies distributions and stacking patterns show that these sediments result from the interaction between fluvial and lacustrine systems, represented by cross-bedded and rippled strata, and varved deposits. The lateral extent of the deformation is some hundred metres and the deformed bed involves the lower-mid part of the 30-metre-thick succession. Deformation affects about 1.5 m of coarse-grained sand, fine-grained sand and rare gravel alternations. The base and top of the deformed layer are defined by planar surfaces: undeformed beds of similar thickness, lithology and facies to the deformed layer occur above and below. Deformation is represented by a complex vertical succession of disturbed layers: each layer shows a general load-structure morphology. It can be described as a multilayered unstable density gradient system: in each bed a partial gravitational re-adjustment occurred after liquefaction. Unequal loading related to lateral variation of both bed thickness and grain packing and porosity is a probable additional driving force that can be described in the undeformed beds. Trigger mechanism recognition for the observed liquefaction features can be based on the study of the geometry of deformed beds and on facies analysis results. Two key factors drive our interpretation: (1) the occurrence of undeformed beds below and above the deformed bed; (2) deformed and undeformed beds showing the same sedimentological features. These field data allow us to exclude the action of internal erosive and/or sedimentary processes (such as overloading, wave action, etc.) as possible trigger agents for liquefaction since deformation is totally absent in beds with similar sedimentary

HTR-PROTEUS PEBBLE BED EXPERIMENTAL PROGRAM CORE 4: RANDOM PACKING WITH A 1:1 MODERATOR-TO-FUEL PEBBLE RATIO

DOE Office of Scientific and Technical Information (OSTI.GOV)

John D. Bess; Leland M. Montierth

2013-03-01

In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters.more » One benchmark experiment was evaluated in this report: Core 4. Core 4 represents the only configuration with random pebble packing in the HTR-PROTEUS series of experiments, and has a moderator-to-fuel pebble ratio of 1:1. Three random configurations were performed. The initial configuration, Core 4.1, was rejected because the method for pebble loading, separate delivery tubes for the moderator and fuel pebbles, may not have been completely random; this core loading was rejected by the experimenters. Cores 4.2 and 4.3 were loaded using a single delivery tube, eliminating the possibility for systematic ordering effects. The second and third cores differed slightly in the quantity of pebbles loaded (40 each of moderator and fuel pebbles), stacked height of the pebbles in the core cavity (0.02 m), withdrawn distance of the stainless steel control rods (20 mm), and withdrawn distance of the autorod (30 mm). The 34 coolant channels in the upper axial reflector and the 33 coolant channels in the lower axial reflector were open. Additionally, the axial graphite fillers used in all other HTR-PROTEUS configurations to create a 12-sided core cavity were not used in the randomly packed cores. Instead, graphite fillers were placed on the cavity floor, creating a funnel-like base, to discourage

HTR-proteus pebble bed experimental program core 4: random packing with a 1:1 moderator-to-fuel pebble ratio

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bess, John D.; Montierth, Leland M.; Sterbentz, James W.

2014-03-01

In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters.more » One benchmark experiment was evaluated in this report: Core 4. Core 4 represents the only configuration with random pebble packing in the HTR-PROTEUS series of experiments, and has a moderator-to-fuel pebble ratio of 1:1. Three random configurations were performed. The initial configuration, Core 4.1, was rejected because the method for pebble loading, separate delivery tubes for the moderator and fuel pebbles, may not have been completely random; this core loading was rejected by the experimenters. Cores 4.2 and 4.3 were loaded using a single delivery tube, eliminating the possibility for systematic ordering effects. The second and third cores differed slightly in the quantity of pebbles loaded (40 each of moderator and fuel pebbles), stacked height of the pebbles in the core cavity (0.02 m), withdrawn distance of the stainless steel control rods (20 mm), and withdrawn distance of the autorod (30 mm). The 34 coolant channels in the upper axial reflector and the 33 coolant channels in the lower axial reflector were open. Additionally, the axial graphite fillers used in all other HTR-PROTEUS configurations to create a 12-sided core cavity were not used in the randomly packed cores. Instead, graphite fillers were placed on the cavity floor, creating a funnel-like base, to discourage

17 CFR Appendix B to Part 37 - Guidance on Compliance With Core Principles

Code of Federal Regulations, 2012 CFR

2012-04-01

..., resources and authority to detect and deter abuses by effectively and affirmatively enforcing its rules... privileges but having no, or only nominal equity, in the facility and non-member market participants or, in... transparent to the member or market participant. Core Principle 3 of section 5a(d) of the Act: MONITORING OF...

Branched GDGT distributions in lakes from Mexico and Central America

NASA Astrophysics Data System (ADS)

Lei, A.; Werne, J. P.; Correa-Metrio, A.; Pérez, L.; Caballero, M.

2017-12-01

The potential to use bacterial derived branched glycerol dialkyl glycerol tetraethers (brGDGTs) to reconstruct mean annual air temperatures from soils sparked significant interest in the terrestrial paleoclimate community, where a high-fidelity paleotemperature proxy is desperately needed. While the source of brGDGTs remains unknown (but are potentially attributed to the highly diverse phylum Acidobacteria), much evidence points to the potential for these bacteria to live not only in the terrestrial environment but also in lake water and sediments as well. Though the application of brGDGTs to lacustrine reconstructions is promising, the initial applications of soil-based MBT/CBT proxy to lacustrine sediments typically resulted in lower temperatures than were reasonable, likely due to additions from lacustrine bacterial brGDGTs. Here, we present data from a suite of >100 lakes in Mexico and Central America, producing a regional core-top calibration different from those developed in other regions. Results indicate a significant role for regional differences in controlling the brGDGTs distribution, likely due to different brGDGT-producing microbial communities thriving under varying environmental conditions. Rigorous development of brGDGT based proxies will improve our understanding of the source and applicability of these biomarkers, and increase confidence in the accuracy of paleotemperature reconstructions to numerous lacustrine records in the region.

Interpretation of the results of the CORA-33 dry core BWR test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ott, L.J.; Hagen, S.

All BWR degraded core experiments performed prior to CORA-33 were conducted under ``wet`` core degradation conditions for which water remains within the core and continuous steaming feeds metal/steam oxidation reactions on the in-core metallic surfaces. However, one dominant set of accident scenarios would occur with reduced metal oxidation under ``dry`` core degradation conditions and, prior to CORA-33, this set had been neglected experimentally. The CORA-33 experiment was designed specifically to address this dominant set of BWR ``dry`` core severe accident scenarios and to partially resolve phenomenological uncertainties concerning the behavior of relocating metallic melts draining into the lower regions ofmore » a ``dry`` BWR core. CORA-33 was conducted on October 1, 1992, in the CORA tests facility at KfK. Review of the CORA-33 data indicates that the test objectives were achieved; that is, core degradation occurred at a core heatup rate and a test section axial temperature profile that are prototypic of full-core nuclear power plant (NPP) simulations at ``dry`` core conditions. Simulations of the CORA-33 test at ORNL have required modification of existing control blade/canister materials interaction models to include the eutectic melting of the stainless steel/Zircaloy interaction products and the heat of mixing of stainless steel and Zircaloy. The timing and location of canister failure and melt intrusion into the fuel assembly appear to be adequately simulated by the ORNL models. This paper will present the results of the posttest analyses carried out at ORNL based upon the experimental data and the posttest examination of the test bundle at KfK. The implications of these results with respect to degraded core modeling and the associated safety issues are also discussed.« less

Core-core and core-valence correlation energy atomic and molecular benchmarks for Li through Ar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ranasinghe, Duminda S.; Frisch, Michael J.; Petersson, George A., E-mail: gpetersson@wesleyan.edu

2015-12-07

We have established benchmark core-core, core-valence, and valence-valence absolute coupled-cluster single double (triple) correlation energies (±0.1%) for 210 species covering the first- and second-rows of the periodic table. These species provide 194 energy differences (±0.03 mE{sub h}) including ionization potentials, electron affinities, and total atomization energies. These results can be used for calibration of less expensive methodologies for practical routine determination of core-core and core-valence correlation energies.

Accumulation and diagenesis of chlorinated hydrocarbons in lacustrine sediments

USGS Publications Warehouse

Elsenreich, S.J.; Capel, P.D.; Robbins, J.A.; Bourbonniere, R.

1989-01-01

Two sediment cores were taken from the Rochester Basin of eastern Lake Ontario and analyzed for the radionuclides 210Pb and 137Cs and several high molecular weight chlorinated hydrocarbons (CHs). The two sites are geographically proximate but differ in sedimentation rate, permitting sedimentation-dependent processes to be factored out. The 210Pb chronology showed a mixed depth of 3-5 cm and an intrinsic time resolution of 11-14 years. Vertically integrated numbers of deposit-feeding oligochaete worms and burrowing organisms are insufficient to homogenize the sediment on the time scale of CH inputs, which are non steady state. U.S. production and sales of polychlorinated biphenyls (PCBs), DDT, Mirex, and hexachlorobenzene (HCB), as determinants of the shape of the input function, adequately predict the overall shape and, in many cases, details in the sedimentary profile. Sediment focusing factors (FF) inferred from 137Cs and 210Pb inventories averaged 1.17 and 1.74 for cores E-30 and G-32, respectively. This permitted CH accumulation rates to be corrected for focusing. Apparent molecular diffusion coefficients modeled for many of the CHs were about (1-3) ?? 10-9 cm2/s.

Analysis of Monolith Cores from an Engineering Scale Demonstration of a Prospective Cast Stone Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crawford, C. L.; Cozzi, A. D.; Hill, K. A.

2016-06-01

The primary disposition path of Low Activity Waste (LAW) at the DOE Hanford Site is vitrification. A cementitious waste form is one of the alternatives being considered for the supplemental immobilization of the LAW that will not be treated by the primary vitrification facility. Washington River Protection Solutions (WRPS) has been directed to generate and collect data on cementitious or pozzolanic waste forms such as Cast Stone. This report documents the coring and leach testing of monolithic samples cored from an engineering-scale demonstration (ES Demo) with non-radioactive simulants. The ES Demo was performed at SRNL in October of 2013 usingmore » the Scaled Continuous Processing Facility (SCPF) to fill an 8.5 ft. diameter x 3.25 ft. high container with simulated Cast Stone grout. The Cast Stone formulation was chosen from the previous screening tests. Legacy salt solution from previous Hanford salt waste testing was adjusted to correspond to the average LAW composition generated from the Hanford Tank Waste Operation Simulator (HTWOS). The dry blend materials, ordinary portland cement (OPC), Class F fly ash, and ground granulated blast furnace slag (GGBFS or BFS), were obtained from Lafarge North America in Pasco, WA. In 2014 core samples originally obtained approximately six months after filling the ES Demo were tested along with bench scale molded samples that were collected during the original pour. A latter set of core samples were obtained in late March of 2015, eighteen months after completion of the original ES Demo. Core samples were obtained using a 2” diameter x 11” long coring bit. The ES Demo was sampled in three different regions consisting of an outer ring, a middle ring and an inner core zone. Cores from these three lateral zones were further segregated into upper, middle and lower vertical segments. Monolithic core samples were tested using the Environmental Protection Agency (EPA) Method 1315, which is designed to provide mass transfer

OPERATION OF A PUBLIC GEOLOGIC CORE AND SAMPLE REPOSITORY IN HOUSTON, TEXAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scott W. Tinker; Beverly Blakeney DeJarnett; Laura C. Zahm

2005-04-01

The Bureau of Economic Geology's Houston Research Center (HRC) is well established as a premier regional research center for geologic research serving not only Houston, but geoscientists from around Texas, the U. S., and even the world. As reported in the 2003-2004 technical progress report to the DOE, the HRC provides a state-of-the-art core viewing facility, two fully equipped conference rooms, and a comprehensive technical library, all available for public use. In addition, the HRC currently houses over 500,000 boxes of rock material, and has space to hold approximately 400,000 more boxes. Use of the facility has continued to increasemore » during this third year of operation; over the past twelve months the HRC has averaged approximately 200 patrons per month. This usage is a combination of individuals describing core, groups of geoscientists holding seminars and workshops, and various industry and government-funded groups holding short courses, workshops, and seminars. The BEG/HRC secured several substantial donations of rock materials and/or cash during this operating period. All of these funds went directly into the endowment. Outreach during 2004 and 2005 included many technical presentations and several publications on the HRC. Several field trips to the facility were held for geoscience professionals and grade school students alike. Goals for the upcoming year involve securing more donations of rock material and cash in order to fully fund the HRC endowment. BEG will also continue to increase the number of patrons using the facility, and we will strive to raise awareness of the HRC's 100,000-volume geoscience technical library.« less

Ground Penetrating Radar, Magnetic and Compositional Analysis of Sediment Cores and Surface Samples: The Relationships Between Lacustrine Sediments and Holocene Lake- Level and Climate Change at Deming Lake, Minnesota, USA

NASA Astrophysics Data System (ADS)

Murray, R.; Lascu, I.; Plank, C.

2007-12-01

Deming Lake is a small (<1 square km), deep (about 17m), meromictic kettle lake situated near the prairie- forest boundary, in Itasca State Park, MN. Because of the lake's location and morphology, the accumulated sediments comprise a high-resolution record of limnological and ecological changes in response to Holocene climate variations. We used a shore perpendicular transect of three cores (located in littoral, mid-slope, and profundal settings) and ground penetrating radar (GPR) profiles to investigate Holocene lake-level variability at Deming. Cores were sampled continuously at a 1-2 cm resolution and sediment composition (in terms of percent organic matter, carbonate material, and minerogenic residue) was determined via loss on ignition (LOI). Isothermal remanent magnetization (IRM) and anhysteretic remanent magnetization (ARM) were used as proxies of magnetic mineral concentration and grain size. Four lithostratigraphic units were identified and correlated between cores based on these analyses. Changes in GPR facies corroborate the correlation between the two shallow cores. In order to inform our interpretation of down-core variations in magnetic properties and LOI values in terms of variations in lake depth, a suite of over 70 modern sediment samples were collected from the basin and analyzed. LOI compositional variability across the basin was high, with no clear trends related to depth or distance from shore. A sharp decrease in minerogenic content was observed at depths consistent with a predicted wave-base of 0.5 m, but aside from this trend it appears the steep slopes of much of the basin promote gravity driven slumping and mixing of sediments at depth. In the profundal sediments IRM values are routinely 5% higher than in the slope and littoral environments, while ARM/IRM ratios indicate an increase in magnetic grain size with water depth. We infer that an increase in coarse organic material in the shallow-water cores of Deming records a period of aridity

A multi-proxy palaeoecological and palaeoclimatic record within full glacial lacustrine deposits, western Tennessee, USA

USGS Publications Warehouse

Grimley, D.A.; Daniel, L.; Kaplan, S.W.; Yansa, C.H.; Curry, B. Brandon; Oches, E.A.

2009-01-01

The Fulton Section, along the Mississippi River in western Tennessee, USA, is a 1km continuous exposure (~20m vertically) of Quaternary fluvial and lacustrine deposits, inset within Eocene sediments and buried by thick loess. Fossiliferous slackwater lake sediments record maximum aggradation during the last two major glaciations, with deposition between ca. 190-140 ka and 24-1814C ka BP, based on amino acid and radiocarbon chronology, respectively. During the onset of full glacial conditions (ca. 24-22 14C ka BP), a relatively permanent shallow lake environment is indicated by ostracods, aquatic molluscs, and both pollen and macrofossils of aquatic plants. By 21.8 14C ka BP, increasing emergent plants, amphibious gastropods (Pomatiopsis) and heavier ??18O compositions suggest marsh-like conditions in a periodically drying lake. The surrounding uplands consisted of Picea-Pinus woodlands mixed with cool-temperate hardwoods (e.g. Quercus, Populus, Carya), grasses and herbs. More open conditions ensued ca. 20 14C ka BP, with loess and slopewash gradually infilling the former lake by 18 14C ka BP. Modern analogue analyses of ostracods and palaeontological evidence imply a full glacial climate similar to today's mixed-boreal zone in central Minnesota, USA, about 98C cooler in mean annual temperature than present-day western Tennessee. Copyright ?? 2009 John Wiley & Sons, Ltd.

MYRRHA: A multipurpose nuclear research facility

NASA Astrophysics Data System (ADS)

Baeten, P.; Schyns, M.; Fernandez, Rafaël; De Bruyn, Didier; Van den Eynde, Gert

2014-12-01

MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) is a multipurpose research facility currently being developed at SCK•CEN. MYRRHA is based on the ADS (Accelerator Driven System) concept where a proton accelerator, a spallation target and a subcritical reactor are coupled. MYRRHA will demonstrate the ADS full concept by coupling these three components at a reasonable power level to allow operation feedback. As a flexible irradiation facility, the MYRRHA research facility will be able to work in both critical as subcritical modes. In this way, MYRRHA will allow fuel developments for innovative reactor systems, material developments for GEN IV and fusion reactors, and radioisotope production for medical and industrial applications. MYRRHA will be cooled by lead-bismuth eutectic and will play an important role in the development of the Pb-alloys technology needed for the LFR (Lead Fast Reactor) GEN IV concept. MYRRHA will also contribute to the study of partitioning and transmutation of high-level waste. Transmutation of minor actinides (MA) can be completed in an efficient way in fast neutron spectrum facilities, so both critical reactors and subcritical ADS are potential candidates as dedicated transmutation systems. However critical reactors heavily loaded with fuel containing large amounts of MA pose reactivity control problems, and thus safety problems. A subcritical ADS operates in a flexible and safe manner, even with a core loading containing a high amount of MA leading to a high transmutation rate. In this paper, the most recent developments in the design of the MYRRHA facility are presented.

Lacustrine Paleoseismology Reveals Earthquake Segmentation of the Alpine Fault, New Zealand

NASA Astrophysics Data System (ADS)

Howarth, J. D.; Fitzsimons, S.; Norris, R.; Langridge, R. M.

2013-12-01

Transform plate boundary faults accommodate high rates of strain and are capable of producing large (Mw>7.0) to great (Mw>8.0) earthquakes that pose significant seismic hazard. The Alpine Fault in New Zealand is one of the longest, straightest and fastest slipping plate boundary transform faults on Earth and produces earthquakes at quasi-periodic intervals. Theoretically, the fault's linearity, isolation from other faults and quasi-periodicity should promote the generation of earthquakes that have similar magnitudes over multiple seismic cycles. We test the hypothesis that the Alpine Fault produces quasi-regular earthquakes that contiguously rupture the southern and central fault segments, using a novel lacustrine paleoseismic proxy to reconstruct spatial and temporal patterns of fault rupture over the last 2000 years. In three lakes located close to the Alpine Fault the last nine earthquakes are recorded as megaturbidites formed by co-seismic subaqueous slope failures, which occur when shaking exceeds Modified Mercalli (MM) VII. When the fault ruptures adjacent to a lake the co-seismic megaturbidites are overlain by stacks of turbidites produced by enhanced fluvial sediment fluxes from earthquake-induced landslides. The turbidite stacks record shaking intensities of MM>IX in the lake catchments and can be used to map the spatial location of fault rupture. The lake records can be dated precisely, facilitating meaningful along strike correlations, and the continuous records allow earthquakes closely spaced in time on adjacent fault segments to be distinguished. The results show that while multi-segment ruptures of the Alpine Fault occurred during most seismic cycles, sequential earthquakes on adjacent segments and single segment ruptures have also occurred. The complexity of the fault rupture pattern suggests that the subtle variations in fault geometry, sense of motion and slip rate that have been used to distinguish the central and southern segments of the Alpine

Paleo-environmental gateways in the eastern Canadian arctic - Recent isotope hydrology and diatom oxygen isotopes from Nettilling Lake, Baffin Island, Canada

NASA Astrophysics Data System (ADS)

Chapligin, B.; Narancic, B.; Meyer, H.; Pienitz, R.

2016-09-01

Nettilling Lake is located on Baffin Island, Nunavut, Canada between the areas of past warming (Canadian High Arctic to the North) and climatic stability (Northern Quebec and Labrador region to the South). Despite being the largest lake in the Nunavut region with a postglacial marine to lacustrine transition history only a few paleo-environmental investigations were completed in this area. The oxygen isotope composition of diatoms (δ18Odiatom) can provide valuable insights into paleo-environmental conditions. Here, the recent (isotope) hydrology and hydrochemical data from the lake are presented to facilitate the interpretation of a δ18Odiatom record from an 82 cm sediment core (Ni-2B). The well-mixed lake (δ18Owater = -17.4‰) is influenced by a heavier (less negative) isotope composition (-18.80‰) from Amadjuak River draining Amadjuak Lake to the South and water of lighter (more negative) isotopic composition (-16.4‰) from the Isurtuq River originating from Penny Ice Cap in the North-East. From the δ18Owater and δ18Odiatom of the topmost sample of core Ni-2B a Δ18Osilica-water of 1000 ln α(silica-water) = 40.2‰ for sub-recent diatoms of Nettilling Lake was calculated matching the known water-silica fractionation for fossil sediments well and thereby showing the general applicability of this proxy for paleo-reconstructions in this region. Extremely large δ18Odiatom variations in the core of more than 13‰ are mainly induced by changes in the isotopic composition of the lake water due to a shift from glaciomarine (δ18Odiatom = +34.6‰) through brackish (+23.4 to +27.2‰) towards lacustrine (+21.5‰) conditions (transition zones glaciomarine to brackish at 69 cm/7300 yr cal. BP and brackish to lacustrine at 35 cm/6000 yr cal. BP) associated with a shift in the degree of salinity. Our study provides the first evidence that paleo-salinity can be reconstructed by δ18Odiatom. Additionally, for the lacustrine section it could be demonstrated that �

Ultrasonic approach to the synthesis of HMX@TATB core-shell microparticles with improved mechanical sensitivity.

PubMed

Huang, Bing; Hao, Xiaofei; Zhang, Haobin; Yang, Zhijian; Ma, Zhigang; Li, Hongzhen; Nie, Fude; Huang, Hui

2014-07-01

To improve the safety of sensitive explosive HMX while maintaining explosion performance, a moderately powerful but insensitive explosive TATB was used to coat HMX microparticles via a facile ultrasonic method. By using Estane as surface modifier and nano-sized TATB as the shell layer, the HMX@TATB core-shell microparticles with a monodisperse size and compact shell structure were successfully constructed. Both scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) results confirmed the formation of perfect core-shell structured composites. Based on a systematic and comparative study of the effect of experimental conditions, a possible formation mechanism of core-shell structure was proposed in detail. Moreover, the perfect core-shell HMX@TATB microparticles exhibited a unique thermal behavior and significantly improved mechanical sensitivity compared with that of the physical mixture. Copyright © 2014 Elsevier B.V. All rights reserved.

A half-million-year record of paleoclimate from the Lake Manix Core, Mojave Desert, California

USGS Publications Warehouse

Reheis, Marith C.; Bright, Jordon; Lund, Steve P.; Miller, David M.; Skipp, Gary; Fleck, Robert J.

2012-01-01

Pluvial lakes in the southwestern U.S. responded sensitively to past climate through effects on rainfall, runoff, and evaporation. Although most studies agree that pluvial lakes in the southwestern U.S. reached their highest levels coeval with glacial stages, the specific timing of increased effective moisture and lake-level rise is debated, particularly for the southwesternmost lakes. We obtained a 45-m core of lacustrine sediment from Lake Manix, the former terminus of the Mojave River prior to about 25 ka, and supplemented data from the core with outcrop studies. These sediments provide a robust record of Mojave River discharge over the last half-million years. Lake Manix persisted from OIS 12 through early OIS 2, including during interstadial OIS 3 and interglacials OIS 5, 7, and 9. The ostracode faunal record displays a shift from an unexpectedly warm, summer-dominated lake hydrology during OIS 12 to predominantly colder, winter-dominated conditions afterwards. The ostracode-based stable isotope record displays a large degree of intra-sample variability and does not mimic other well-known isotopic records of climate change. Evaporation likely buffered the Manix δ18O record from most of the expected isotopic differences between interglacial and glacial-interval discharge. Isotopically depleted and stable lakes occurred only four to six times, most notably during OIS 7 and OIS 9. Internal drainage-basin changes also affected the isotopic record. Persistence of lakes in the Manix basin during interglacials requires atmospheric or oceanic circulation controls on the mean position of the Pacific storm track other than large ice sheets. We propose that the relative strength and sign of the Northern Annular Mode (NAM) and its influence on atmospheric river-derived precipitation is a potential explanation.

Organic petrology and geochemistry of mudrocks from the lacustrine Lucaogou Formation, Santanghu Basin, northwest China: Application to lake basin evolution

USGS Publications Warehouse

Hackley, Paul C.; Fishman, Neil; Wu, Tao; Baugher, Gregory

2016-01-01

Exploration for tight oil in the frontier Santanghu Basin of northwest China has resulted in recent commercial discoveries sourced from the lacustrine Upper Permian Lucaogou Formation, already considered a “world class source rock” in the Junggar Basin to the west. Here we apply an integrated analytical program to carbonate-dominated mudrocks from the Lucaogou Formation in Santanghu Basin to document the nature of organic matter (OM) in the context of an evolving lake system. The organic-rich samples (TOC 2.8–11.4 wt%; n = 10) were widely spaced from an ~ 200 m cored section, interpreted from textural and mineralogical evidence to document transition from a lower under-filled to an overlying balanced-filled lake. Organic matter is dominated by moderate to strongly fluorescent amorphous material with Type I geochemical signature (HI values 510–755; n = 10) occurring in a continuum from lamellar stringers, 10–20 μm thick, some ≥ 1 mm in length (possible microbial mat; preserved only in lower under-filled section) to finely-disseminated amorphous groundmass intimately intermixed with mineral matrix. Biomarkers for methanotrophs and photosynthetic cyanobacteria indicate a complex microbial consortium. A unicellular prasinophyte green alga(?), similar to Tasmanites in marine rocks, is present as discrete flattened discs 50–100 μm in diameter. Type III OM including vitrinite (some fluorescent) and inertinite also is abundant. Solid bitumen, indicating local kerogen conversion, fills voids and occurs throughout the cored section. Vitrinite reflectance values are 0.47–0.58%, consistent with strong OM fluorescence but may be “suppressed”. Other proxies, e.g., biomarker parameters, indicate the Lucaogou Formation is in the early oil window at this location. On average, slightly more amorphous OM and telalginite are present in the lower section, consistent with a shallow, stratified, saline environment with low sediment dilution. More

Composite Cores

NASA Technical Reports Server (NTRS)

1990-01-01

Spang & Company's new configuration of converter transformer cores is a composite of gapped and ungapped cores assembled together in concentric relationship. The net effect of the composite design is to combine the protection from saturation offered by the gapped core with the lower magnetizing requirement of the ungapped core. The uncut core functions under normal operating conditions and the cut core takes over during abnormal operation to prevent power surges and their potentially destructive effect on transistors. Principal customers are aerospace and defense manufacturers. Cores also have applicability in commercial products where precise power regulation is required, as in the power supplies for large mainframe computers.

Optimizing performance by improving core stability and core strength.

PubMed

Hibbs, Angela E; Thompson, Kevin G; French, Duncan; Wrigley, Allan; Spears, Iain

2008-01-01

Core stability and core strength have been subject to research since the early 1980s. Research has highlighted benefits of training these processes for people with back pain and for carrying out everyday activities. However, less research has been performed on the benefits of core training for elite athletes and how this training should be carried out to optimize sporting performance. Many elite athletes undertake core stability and core strength training as part of their training programme, despite contradictory findings and conclusions as to their efficacy. This is mainly due to the lack of a gold standard method for measuring core stability and strength when performing everyday tasks and sporting movements. A further confounding factor is that because of the differing demands on the core musculature during everyday activities (low load, slow movements) and sporting activities (high load, resisted, dynamic movements), research performed in the rehabilitation sector cannot be applied to the sporting environment and, subsequently, data regarding core training programmes and their effectiveness on sporting performance are lacking. There are many articles in the literature that promote core training programmes and exercises for performance enhancement without providing a strong scientific rationale of their effectiveness, especially in the sporting sector. In the rehabilitation sector, improvements in lower back injuries have been reported by improving core stability. Few studies have observed any performance enhancement in sporting activities despite observing improvements in core stability and core strength following a core training programme. A clearer understanding of the roles that specific muscles have during core stability and core strength exercises would enable more functional training programmes to be implemented, which may result in a more effective transfer of these skills to actual sporting activities.

Lacustrine fan delta deposition alongside intrabasinal structural highs in rift basins: an example from the Early Cretaceous Jiuquan Basin, Northwestern China

NASA Astrophysics Data System (ADS)

Zhang, Chengcheng; Muirhead, James D.; Wang, Hua; Chen, Si; Liao, Yuantao; Lu, Zongsheng; Wei, Jun

2018-01-01

Development of fan deltas alongside intrabasinal structural highs has been overlooked compared to those forming on basin margins. However, these fan deltas may provide important clues regarding the tectonic and climatic controls on deposition during rift development. This paper documents fan delta deposition alongside an intrabasinal structural high within the Early Cretaceous Xiagou Formation of the Jiuquan Basin, China, using subsurface geological and geophysical data. Deposits observed in drill core support fan delta deposition occurring almost exclusively through subaerial and subaqueous gravity flows. Subsurface mapping reveals a consistent decrease in the areal extent of fan deltas from lowstand to highstand system tracts, suggesting that deposition alongside the structural high is sensitive to lake-level changes. The temporal and spatial distribution of the fan deltas display retrogradational stacking patterns, where fan deltas exhibit a decreasing lateral extent up-sequence until fan delta deposition terminated and was replaced by deposition of fine-grained lacustrine deposits. The retrogradational stacking patterns observed alongside the intrabasinal structural high are not observed in fan deltas along the basin margin in the lower parts of the Xiagou Formation. Subsidence profiles also show differential subsidence across the basin during the earliest stages of this formation, likely resulting from border fault movements. These data suggest that non-uniform stacking patterns in the lower parts of the Xiagou Formation reflect basin-scale tectonic movements as the dominant control on synrift deposition patterns. However, later stages of Xiagou Formation deposition were characterized by uniform subsidence across the basin, and uniform retrogradational stacking patterns for fan deltas alongside the intrabasinal structural high and border fault. These observations suggest that basin-scale tectonic movements played a relatively limited role in controlling

Milankovitch cyclicity in the paleotropical, fluvial, Late Triassic age strata recovered by the Colorado Plateau Coring Project (CPCP)

NASA Astrophysics Data System (ADS)

Olsen, P. E.; Mundil, R.; Kent, D.; Rasmussen, C.

2017-12-01

Two questions addressed by the CPCP are: 1) is Milankovitch-paced climate cyclicity recorded in the fluvial Late Triassic age Chinle Formation ( 227-202 Ma); and 2) do geochronological data from the Chinle support the Newark-Hartford astrochronological polarity time scale (1) (APTS). To these ends we examined the upper 157 m (stratigraphic thickness) of Petrified Forest National Park core 1A (Owl Rock, Petrified Forest, and upper Sonsela members), consisting mostly of massive red paleosols and less important fluvial sandstones. A linear age model tied to new U-Pb zircon CA ID-TIMS dates from core 1A, consistent with published data from outcrop (2), yields a duration of about 5 Myr for this interval. Magnetic susceptibility variations, interpreted as reflecting penecontemporaneous soil and sandstone redox conditions, show a clear 12 m cycle corresponding to a 400 kyr cycle based on Fourier analysis in both core and hole. Similar cyclicity is apparent in spectrophotometric data, largely reflecting hematite variability. Weak, higher frequency cycles are present consistent with 100 kyr variability. There is no interpretable 20 kyr signal. Such cyclicity is not an anticipated direct effect of Milankvitch insolation variations, but must reflect non-linear integration of variability that changes dramatically at the eccentricity-scale, brought about by the sedimentary and climate systems. Our results support a direct 405 kyr-level correlation between the fluvial medial Chinle and lacustrine Newark Basin section (middle Passaic Formation), consistent with new and published (3) paleomagnetic polarity stratigraphy from the Chinle, showing that the Milankovitch eccentricity cycles are recorded in lower accumulation rate fluvial systems. Our results also independently support the continuity of the Newark Basin section and corroborate the Newark-Hartford APTS, not allowing for a multi-million year hiatus in the Passaic Formation, as has been asserted (4). We anticipate further

The Colorado Plateau Coring Project: A Continuous Cored Non-Marine Record of Early Mesozoic Environmental and Biotic Change

NASA Astrophysics Data System (ADS)

Irmis, Randall; Olsen, Paul; Geissman, John; Gehrels, George; Kent, Dennis; Mundil, Roland; Rasmussen, Cornelia; Giesler, Dominique; Schaller, Morgan; Kürschner, Wolfram; Parker, William; Buhedma, Hesham

2017-04-01

The early Mesozoic is a critical time in earth history that saw the origin of modern ecosystems set against the back-drop of mass extinction and sudden climate events in a greenhouse world. Non-marine sedimentary strata in western North America preserve a rich archive of low latitude terrestrial ecosystem and environmental change during this time. Unfortunately, frequent lateral facies changes, discontinuous outcrops, and a lack of robust geochronologic constraints make lithostratigraphic and chronostratigraphic correlation difficult, and thus prevent full integration of these paleoenvironmental and paleontologic data into a regional and global context. The Colorado Plateau Coring Project (CPCP) seeks to remedy this situation by recovering a continuous cored record of early Mesozoic sedimentary rocks from the Colorado Plateau of the western United States. CPCP Phase 1 was initiated in 2013, with NSF- and ICDP-funded drilling of Triassic units in Petrified Forest National Park, northern Arizona, U.S.A. This phase recovered a 520 m core (1A) from the northern part of the park, and a 240 m core (2B) from the southern end of the park, comprising the entire Lower-Middle Triassic Moenkopi Formation, and most of the Upper Triassic Chinle Formation. Since the conclusion of drilling, the cores have been CT scanned at the University of Texas - Austin, and split, imaged, and scanned (e.g., XRF, gamma, and magnetic susceptibility) at the University of Minnesota LacCore facility. Subsequently, at the Rutgers University Core Repository, core 1A was comprehensively sampled for paleomagnetism, zircon geochronology, petrography, palynology, and soil carbonate stable isotopes. LA-ICPMS U-Pb zircon analyses are largely complete, and CA-TIMS U-Pb zircon, paleomagnetic, petrographic, and stable isotope analyses are on-going. Initial results reveal numerous horizons with a high proportion of Late Triassic-aged primary volcanic zircons, the age of which appears to be a close

Late Noachian Icy Highlands climate model: Exploring the possibility of transient melting and fluvial/lacustrine activity through peak annual and seasonal temperatures

NASA Astrophysics Data System (ADS)

Palumbo, Ashley M.; Head, James W.; Wordsworth, Robin D.

2018-01-01

The nature of the Late Noachian climate of Mars remains one of the outstanding questions in the study of the evolution of martian geology and climate. Despite abundant evidence for flowing water (valley networks and open/closed basin lakes), climate models have had difficulties reproducing mean annual surface temperatures (MAT) > 273 K in order to generate the ;warm and wet; climate conditions presumed to be necessary to explain the observed fluvial and lacustrine features. Here, we consider a ;cold and icy; climate scenario, characterized by MAT ∼225 K and snow and ice distributed in the southern highlands, and ask: Does the formation of the fluvial and lacustrine features require continuous ;warm and wet; conditions, or could seasonal temperature variation in a ;cold and icy; climate produce sufficient summertime ice melting and surface runoff to account for the observed features? To address this question, we employ the 3D Laboratoire de Météorologie Dynamique global climate model (LMD GCM) for early Mars and (1) analyze peak annual temperature (PAT) maps to determine where on Mars temperatures exceed freezing in the summer season, (2) produce temperature time series at three valley network systems and compare the duration of the time during which temperatures exceed freezing with seasonal temperature variations in the Antarctic McMurdo Dry Valleys (MDV) where similar fluvial and lacustrine features are observed, and (3) perform a positive-degree-day analysis to determine the annual volume of meltwater produced through this mechanism, estimate the necessary duration that this process must repeat to produce sufficient meltwater for valley network formation, and estimate whether runoff rates predicted by this mechanism are comparable to those required to form the observed geomorphology of the valley networks. When considering an ambient CO2 atmosphere, characterized by MAT ∼225 K, we find that: (1) PAT can exceed the melting point of water (>273 K) in

Event Reconstruction for Many-core Architectures using Java

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graf, Norman A.; /SLAC

Although Moore's Law remains technically valid, the performance enhancements in computing which traditionally resulted from increased CPU speeds ended years ago. Chip manufacturers have chosen to increase the number of core CPUs per chip instead of increasing clock speed. Unfortunately, these extra CPUs do not automatically result in improvements in simulation or reconstruction times. To take advantage of this extra computing power requires changing how software is written. Event reconstruction is globally serial, in the sense that raw data has to be unpacked first, channels have to be clustered to produce hits before those hits are identified as belonging tomore » a track or shower, tracks have to be found and fit before they are vertexed, etc. However, many of the individual procedures along the reconstruction chain are intrinsically independent and are perfect candidates for optimization using multi-core architecture. Threading is perhaps the simplest approach to parallelizing a program and Java includes a powerful threading facility built into the language. We have developed a fast and flexible reconstruction package (org.lcsim) written in Java that has been used for numerous physics and detector optimization studies. In this paper we present the results of our studies on optimizing the performance of this toolkit using multiple threads on many-core architectures.« less

Integration of the SSPM and STAGE with the MPACT Virtual Facility Distributed Test Bed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cipiti, Benjamin B.; Shoman, Nathan

The Material Protection Accounting and Control Technologies (MPACT) program within DOE NE is working toward a 2020 milestone to demonstrate a Virtual Facility Distributed Test Bed. The goal of the Virtual Test Bed is to link all MPACT modeling tools, technology development, and experimental work to create a Safeguards and Security by Design capability for fuel cycle facilities. The Separation and Safeguards Performance Model (SSPM) forms the core safeguards analysis tool, and the Scenario Toolkit and Generation Environment (STAGE) code forms the core physical security tool. These models are used to design and analyze safeguards and security systems and generatemore » performance metrics. Work over the past year has focused on how these models will integrate with the other capabilities in the MPACT program and specific model changes to enable more streamlined integration in the future. This report describes the model changes and plans for how the models will be used more collaboratively. The Virtual Facility is not designed to integrate all capabilities into one master code, but rather to maintain stand-alone capabilities that communicate results between codes more effectively.« less

Hominin Sites and Paleolakes Drilling Project. Chew Bahir, southern Ethiopia: How to get from three tonnes of sediment core to > 500 ka of continuous climate history?

NASA Astrophysics Data System (ADS)

Foerster, Verena; Asrat, Asfawossen; Cohen, Andrew S.; Gromig, Raphael; Günter, Christina; Junginger, Annett; Lamb, Henry F.; Schaebitz, Frank; Trauth, Martin H.

2016-04-01

In search of the environmental context of the evolution and dispersal of Homo sapiens and our close relatives within and beyond the African continent, the ICDP-funded Hominin Sites and Paleolakes Drilling Project (HSPDP) has recently cored five fluvio-lacustrine archives of climate change in East Africa. The sediment cores collected in Ethiopia and Kenya are expected to provide valuable insights into East African environmental variability during the last ~3.5 Ma. The tectonically-bound Chew Bahir basin in the southern Ethiopian rift is one of the five sites within HSPDP, located in close proximity to the Lower Omo River valley, the site of the oldest known fossils of anatomically modern humans. In late 2014, the two cores (279 and 266 m long respectively, HSPDP-CHB14-2A and 2B) were recovered, summing up to nearly three tonnes of mostly calcareous clays and silts. Deciphering an environmental record from multiple records, from the source region of modern humans could eventually allow us to reconstruct the pronounced variations of moisture availability during the transition into Middle Stone Age, and its implications for the origin and dispersal of Homo sapiens. Here we present the first results of our analysis of the Chew Bahir cores. Following the HSPDP protocols, the two parallel Chew Bahir sediment cores have been merged into one single, 280 m long and nearly continuous (>90%) composite core on the basis of a high resolution MSCL data set (e.g., magnetic susceptibility, gamma ray density, color intensity transects, core photographs). Based on the obvious cyclicities in the MSCL, correlated with orbital cycles, the time interval covered by our sediment archive of climate change is inferred to span the last 500-600 kyrs. Combining our first results from the long cores with the results from the accomplished pre-study of short cores taken in 2009/10 along a NW-SE transect across the basin (Foerster et al., 2012, Trauth et al., 2015), we have developed a hypothesis

Development and psychometric evaluation of the Core Nurse Resource Scale.

PubMed

Simpson, Michelle R

2010-11-01

To examine the factor structure, internal consistency reliability and concurrent-related validity of the Core Nurse Resource Scale. A cross-sectional survey study design was used to obtain a sample of 149 nurses and nursing staff [Registered Nurse (RNs), Licensed Practical Nurse (LPNs) and Certified Nursing Assistant (CNAs)] working in long-term care facilities. Exploratory factor analysis, Cronbach's alpha and bivariate correlations were used to evaluate validity and reliability. Exploratory factor analysis yielded a scale with 18 items on three factors, accounting for 52% of the variance in scores. Internal consistency reliability for the composite and Core Nurse Resource Scale factors ranged from 0.79 to 0.91. The Core Nurse Resource Scale composite scale and subscales correlated positively with a measure of work engagement (r=0.247-0.572). The initial psychometric evaluation of the Core Nurse Resource Scale demonstrates it is a sound measure. Further validity and reliability assessment will need to be explored and assessed among nurses and other nursing staff working in other practice settings. The intent of the Core Nurse Resource Scale is to evaluate the presence of physical, psychological and social resources of the nursing work environment, to identify workplaces at risk for disengaged (low work engagement) nursing staff and to provide useful diagnostic information to healthcare administrators interested in interventions to improve the nursing work environment. © 2010 The Author. Journal compilation © 2010 Blackwell Publishing Ltd.

Anatomy of major coal successions: Facies analysis and sequence architecture of a brown coal-bearing valley fill to lacustrine tract (Upper Valdarno Basin, Northern Apennines, Italy)

NASA Astrophysics Data System (ADS)

Ielpi, Alessandro

2012-07-01

A late Pliocene incised valley fill to lacustrine succession, which contains an interbedded brown coal seam (< 20 m thick), is examined in terms of facies analysis, physical stratigraphy and sequence architecture. The succession (< 50 m thick) constitutes the first depositional event of the Castelnuovo Synthem, which is the oldest unconformity bounded stratigraphic unit of the nonmarine Upper Valdarno Basin, Northern Apennines (Italy). The integration of field surveys and borehole logs identified the following event sequence: first valley filling stages by coarse alluvial fan and channelised streams; the progressive setting of low gradient floodbasins with shallow floodplain lakes; subsequent major waterlogging and extensive peat mire development; and system drowning and establishment of permanent lacustrine conditions. The deposits are grouped in a set of nested valley fills and are arranged as high-frequency depositional sequences. The sequences are bounded by minor erosive truncations and have distinctive upward trends: lowstand system tract thinning; transgressive system tract thickening; highstand system tract thinning and eventual non-deposition; and the smoothing of along-sequence boundary sub-aerial incisions. Such features fit in with the notion of an idealised model where second-order (high-frequency) fluctuations, modulated by first-order (low-frequency) base-level rising, have short-lived standing + falling phases and prolonged transgressions, respectively. Furthermore, the general sequence architecture reveals how a mixed palustrine-siliciclastic system differs substantially from a purely siliciclastic one. In the transgressive phases, terrigenous starvation induces prevailing peat accumulation, generating abnormally thick transgressive system tracts that eventually come to occupy much of the same transgression-generated accommodation space. In the highstand phases, the development of thick highstand system tracts is then prevented by sediment upstream

Source facies and oil families of the Malay Basin, Malaysia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Creaney, S.; Hussein, A.H.; Curry, D.J.

1994-07-01

The Malay Basin consists of a number of separate petroleum systems, driven exclusively by nonmarine source rocks. These systems range from lower Oligocene to middle Miocene and show a progression from lacustrine-dominated source facies in the lower Oligocene to lower Miocene section to coastal plain/delta plain coal-related sources in the lower to middle Miocene section. Two lacustrine sources are recognized in the older section, and multiple source/reservoir pairs are recognized in the younger coaly section. The lacustrine sources can be recognized using well-log analysis combined with detailed core and sidewall core sampling. Chemically, they are characterized by low pristane/phytane ratios,more » low oleanane contents, and a general absence of resin-derived terpanes. These sources have TOCs in the 1.0-4.0% range and hydrogen indices of up to 750. In contrast, the coal-related sources are chemically distinct with pristane/phytane ratios of up to 8, very high oleanane contents, and often abundant resinous compounds. All these sources are generally overmature in the basin center and immature toward the basin margin. The oils sourced from all sources in the Malay Basin are generally low in sulfur and of very high economic value. Detailed biomarker analysis of the oils in the Malay Basin has allowed the recognition of families associated with the above sources and demonstrated that oil migration has been largely strata parallel with little cross-stratal mixing of families.« less

A Strategy for Fabricating Porous PdNi@Pt Core-shell Nanostructures and Their Enhanced Activity and Durability for the Methanol Electrooxidation

PubMed Central

Liu, Xinyu; Xu, Guangrui; Chen, Yu; Lu, Tianhong; Tang, Yawen; Xing, Wei

2015-01-01

Three-dimensionally (3D) porous morphology of nanostructures can effectively improve their electrocatalytic activity and durability for various electrochemical reactions owing to big surface area and interconnected structure. Cyanogel, a jelly-like inorganic polymer, can be used to synthesize various three-dimensionally (3D) porous alloy nanomaterials owing to its double-metal property and particular 3D backbone. Here, 3D porous PdNi@Pt core-shell nanostructures (CSNSs) are facilely synthesized by first preparing the Pd-Ni alloy networks (Pd-Ni ANWs) core via cyanogel-reduction method followed by a galvanic displacement reaction to generate the Pt-rich shell. The as-synthesized PdNi@Pt CSNSs exhibit a much improved catalytic activity and durability for the methanol oxidation reaction (MOR) in the acidic media compared to the commercial used Pt black because of their specific structural characteristics. The facile and mild method described herein is highly attractive for the synthisis of 3D porous core-shell nanostructures. PMID:25557190

Facility for testing ice drills

NASA Astrophysics Data System (ADS)

Nielson, Dennis L.; Delahunty, Chris; Goodge, John W.; Severinghaus, Jeffery P.

2017-05-01

The Rapid Access Ice Drill (RAID) is designed for subsurface scientific investigations in Antarctica. Its objectives are to drill rapidly through ice, to core samples of the transition zone and bedrock, and to leave behind a borehole observatory. These objectives required the engineering and fabrication of an entirely new drilling system that included a modified mining-style coring rig, a unique fluid circulation system, a rod skid, a power unit, and a workshop with areas for the storage of supplies and consumables. An important milestone in fabrication of the RAID was the construction of a North American Test (NAT) facility where we were able to test drilling and fluid processing functions in an environment that is as close as possible to that expected in Antarctica. Our criteria for site selection was that the area should be cold during the winter months, be located in an area of low heat flow, and be at relatively high elevation. We selected a site for the facility near Bear Lake, Utah, USA. The general design of the NAT well (NAT-1) started with a 27.3 cm (10.75 in.) outer casing cemented in a 152 m deep hole. Within that casing, we hung a 14 cm (5.5 in.) casing string, and, within that casing, a column of ice was formed. The annulus between the 14 and 27.3 cm casings provided the path for circulation of a refrigerant. After in-depth study, we chose to use liquid CO2 to cool the hole. In order to minimize the likelihood of the casing splitting due to the volume increase associated with freezing water, the hole was first cooled and then ice was formed in increments from the bottom upward. First, ice cubes were placed in the inner liner and then water was added. Using this method, a column of ice was incrementally prepared for drilling tests. The drilling tests successfully demonstrated the functioning of the RAID system. Reproducing such a facility for testing of other ice drilling systems could be advantageous to other research programs in the future.

Water, sanitation and hygiene in Jordan's healthcare facilities.

PubMed

Khader, Yousef Saleh

2017-08-14

Purpose The purpose of this paper is to determine water availability, sanitation and hygiene (WSH) services, and healthcare waste management in Jordan healthcare facilities. Design/methodology/approach In total, 19 hospitals (15 public and four private) were selected. The WSH services were assessed in hospitals using the WSH in health facilities assessment tool developed for this purpose. Findings All hospitals (100 percent) had a safe water source and most (84.2 percent) had functional water sources to provide enough water for users' needs. All hospitals had appropriate and sufficient gender separated toilets in the wards and 84.2 percent had the same in outpatient settings. Overall, 84.2 percent had sufficient and functioning handwashing basins with soap and water, and 79.0 percent had sufficient showers. Healthcare waste management was appropriately practiced in all hospitals. Practical implications Jordan hospital managers achieved major achievements providing access to drinking water and improved sanitation. However, there are still areas that need improvements, such as providing toilets for patients with special needs, establishing handwashing basins with water and soap near toilets, toilet maintenance and providing sufficient trolleys for collecting hazardous waste. Efforts are needed to integrate WSH service policies with existing national policies on environmental health in health facilities, establish national standards and targets for the various healthcare facilities to increase access and improve services. Originality/value There are limited WSH data on healthcare facilities and targets for basic coverage in healthcare facilities are also lacking. A new assessment tool was developed to generate core WSH indicators and to assess WSH services in Jordan's healthcare facilities. This tool can be used by a non-WSH specialist to quickly assess healthcare facility-related WSH services and sanitary hazards in other countries. This tool identified some areas

Space Station Furnace Facility Preliminary Project Implementation Plan (PIP). Volume 2, Appendix 2

NASA Technical Reports Server (NTRS)

Perkey, John K.

1992-01-01

The Space Station Furnace Facility (SSFF) is an advanced facility for materials research in the microgravity environment of the Space Station Freedom and will consist of Core equipment and various sets of Furnace Module (FM) equipment in a three-rack configuration. This Project Implementation Plan (PIP) document was developed to satisfy the requirements of Data Requirement Number 4 for the SSFF study (Phase B). This PIP shall address the planning of the activities required to perform the detailed design and development of the SSFF for the Phase C/D portion of this contract.

Mycorrhizal fungal growth responds to soil characteristics, but not host plant identity, during a primary lacustrine dune succession.

PubMed

Sikes, Benjamin A; Maherali, Hafiz; Klironomos, John N

2014-04-01

Soil factors and host plant identity can both affect the growth and functioning of mycorrhizal fungi. Both components change during primary succession, but it is unknown if their relative importance to mycorrhizas also changes. This research tested how soil type and host plant differences among primary successional stages determine the growth and plant effects of arbuscular mycorrhizal (AM) fungal communities. Mycorrhizal fungal community, plant identity, and soil conditions were manipulated among three stages of a lacustrine sand dune successional series in a fully factorial greenhouse experiment. Late succession AM fungi produced more arbuscules and soil hyphae when grown in late succession soils, although the community was from the same narrow phylogenetic group as those in intermediate succession. AM fungal growth did not differ between host species, and plant growth was similarly unaffected by different AM fungal communities. These results indicate that though ecological filtering and/or adaptation of AM fungi occurs during this primary dune succession, it more strongly reflects matching between fungi and soils, rather than interactions between fungi and host plants. Thus, AM fungal performance during this succession may not depend directly on the sequence of plant community succession.

HTR-PROTEUS Pebble Bed Experimental Program Cores 1, 1A, 2, and 3: Hexagonal Close Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

DOE Office of Scientific and Technical Information (OSTI.GOV)

John D. Bess; Barbara H. Dolphin; James W. Sterbentz

2013-03-01

In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters.more » Four benchmark experiments were evaluated in this report: Cores 1, 1A, 2, and 3. These core configurations represent the hexagonal close packing (HCP) configurations of the HTR-PROTEUS experiment with a moderator-to-fuel pebble ratio of 1:2. Core 1 represents the only configuration utilizing ZEBRA control rods. Cores 1A, 2, and 3 use withdrawable, hollow, stainless steel control rods. Cores 1 and 1A are similar except for the use of different control rods; Core 1A also has one less layer of pebbles (21 layers instead of 22). Core 2 retains the first 16 layers of pebbles from Cores 1 and 1A and has 16 layers of moderator pebbles stacked above the fueled layers. Core 3 retains the first 17 layers of pebbles but has polyethylene rods inserted between pebbles to simulate water ingress. The additional partial pebble layer (layer 18) for Core 3 was not included as it was used for core operations and not the reported critical configuration. Cores 1, 1A, 2, and 3 were determined to be acceptable benchmark experiments.« less

HTR-PROTEUS Pebble Bed Experimental Program Cores 1, 1A, 2, and 3: Hexagonal Close Packing with a 1:2 Moderator-to-Fuel Pebble Ratio

DOE Office of Scientific and Technical Information (OSTI.GOV)

John D. Bess; Barbara H. Dolphin; James W. Sterbentz

2012-03-01

In its deployment as a pebble bed reactor (PBR) critical facility from 1992 to 1996, the PROTEUS facility was designated as HTR-PROTEUS. This experimental program was performed as part of an International Atomic Energy Agency (IAEA) Coordinated Research Project (CRP) on the Validation of Safety Related Physics Calculations for Low Enriched HTGRs. Within this project, critical experiments were conducted for graphite moderated LEU systems to determine core reactivity, flux and power profiles, reaction-rate ratios, the worth of control rods, both in-core and reflector based, the worth of burnable poisons, kinetic parameters, and the effects of moisture ingress on these parameters.more » Four benchmark experiments were evaluated in this report: Cores 1, 1A, 2, and 3. These core configurations represent the hexagonal close packing (HCP) configurations of the HTR-PROTEUS experiment with a moderator-to-fuel pebble ratio of 1:2. Core 1 represents the only configuration utilizing ZEBRA control rods. Cores 1A, 2, and 3 use withdrawable, hollow, stainless steel control rods. Cores 1 and 1A are similar except for the use of different control rods; Core 1A also has one less layer of pebbles (21 layers instead of 22). Core 2 retains the first 16 layers of pebbles from Cores 1 and 1A and has 16 layers of moderator pebbles stacked above the fueled layers. Core 3 retains the first 17 layers of pebbles but has polyethylene rods inserted between pebbles to simulate water ingress. The additional partial pebble layer (layer 18) for Core 3 was not included as it was used for core operations and not the reported critical configuration. Cores 1, 1A, 2, and 3 were determined to be acceptable benchmark experiments.« less

Late Holocene Environmental Reconstruction and Flood Records of Lake Bafa, Western Turkey

NASA Astrophysics Data System (ADS)

Yalamaz, Burak; Bulkan, Özlem; Namık Çaǧatay, M.; Acar, Dursun

2016-04-01

Lake Bafa is a significant inland lake located in the Büyük Menderes River Basin near the Aegean Sea in the horst and graben system of western Turkey. Lake Bafa was part of the ancient Gulf of Latmos that was gradually filled by the prograding sediments of Büyük Menderes River during the Holocene transgression, and resulted in the creation of the Lake in the southern part. The lake is presently located 15 km from the shoreline, 2 m above sea level. It has a maximum depth of 21 m and surface area of 60 km2. We used multi-proxy analyses of a 4.17 m-long core extending back to ca. 2300 years from the central depo centre of the lake. The objectives are to reconstruct the environmental evolution of the Lake Bafa as it changed from a marginal marine to a lacustrine environment, and to investigate the flood records during the past 2300 yrs. The core is composed of three units: an uppermost lacustrine unit, a unit representing marine to lacustrine conditions and a lowermost marine unit. The uppermost lacustrine unit is 1 m-thick, homogenous clayey silt mud layer with relatively high total organic carbon (TOC= 2.5 - 4.5 %), high total inorganic carbon (TIC = 1.8 -4.5 %) and low detrital input (Si, K, Zr, Ti). According to AMS radiocarbon dating, it was deposited over the last 600 yrs under brackish lacustrine conditions. The underlying unit is 2 m-thick, and consists of banded mud layers with relatively low TOC (1.2-4 %) and TIC (1.2-3.5) contents and high detrital input. Its fossil content, with scarce Cardium sp. and Ammonia sp., indicates that it was deposited under brackish water conditions and represents a transition from marine to lacustrine environments. The unit was deposited between ca. 600 and 1750 yrs BP, and includes frequent flood units ranging up to 10 cm-thick fine sand- to clay-bearing coarse silt. The lowermost unit is characterized by relatively high TOC (2-5.5 %), TIC (1.5-3.5 %) contents and high detrital input. With its abundant Cardium sp. and

Facile transformation of FeO/Fe3O4 core-shell nanocubes to Fe3O4 via magnetic stimulation

NASA Astrophysics Data System (ADS)

Lak, Aidin; Niculaes, Dina; Anyfantis, George C.; Bertoni, Giovanni; Barthel, Markus J.; Marras, Sergio; Cassani, Marco; Nitti, Simone; Athanassiou, Athanassia; Giannini, Cinzia; Pellegrino, Teresa

2016-09-01

Here, we propose the use of magnetic hyperthermia as a means to trigger the oxidation of Fe1-xO/Fe3-δO4 core-shell nanocubes to Fe3-δO4 phase. As a first relevant consequence, the specific absorption rate (SAR) of the initial core-shell nanocubes doubles after exposure to 25 cycles of alternating magnetic field stimulation. The improved SAR value was attributed to a gradual transformation of the Fe1-xO core to Fe3-δO4, as evidenced by structural analysis including high resolution electron microscopy and Rietveld analysis of X-ray diffraction patterns. The magnetically oxidized nanocubes, having large and coherent Fe3-δO4 domains, reveal high saturation magnetization and behave superparamagnetically at room temperature. In comparison, the treatment of the same starting core-shell nanocubes by commonly used thermal annealing process renders a transformation to γ-Fe2O3. In contrast to other thermal annealing processes, the method here presented has the advantage of promoting the oxidation at a macroscopic temperature below 37 °C. Using this soft oxidation process, we demonstrate that biotin-functionalized core-shell nanocubes can undergo a mild self-oxidation transformation without losing their functional molecular binding activity.

Green synthesis of CuInS2/ZnS core-shell quantum dots by facile solvothermal route with enhanced optical properties

NASA Astrophysics Data System (ADS)

Jindal, Shikha; Giripunje, Sushama M.; Kondawar, Subhash B.; Koinkar, Pankaj

2018-03-01

We report an eco-friendly green synthesis of highly luminescent CuInS2/ZnS core-shell quantum dots (QDs) with average particle size ∼ 3.9 nm via solvothermal process. The present study embodies the intensification of CuInS2/ZnS QDs properties by the shell growth on the CuInS2 QDs. The as-prepared CuInS2 core and CuInS2/ZnS core-shell QDs have been characterized using a range of optical and structural techniques. By adopting a low temperature growth of CuInS2 core and high temperature growth of CuInS2/ZnS core-shell growth, the tuning of absorption and photoluminescence emission spectra were observed. Optical absorption and photoluminescence spectroscopy probe the effect of ZnS passivation on the electronic structure of the CuInS2 dots. In addition, QDs have been scrutinized using ultra violet photoelectron spectroscopy (UPS) to explore their electronic band structure. The band level positions of CuInS2 and CuInS2/ZnS QDs suffices the demand of non-toxic acceptor material for electronic devices. The variation in electronic energy levels of CuInS2 core with the coating of wide band gap ZnS shell influence the removal of trap assisted recombination on the surface of the core. QDs exhibited tunable emission from red to orange region. These studies reveal the feasibility of QDs in photovoltaic and light emitting diodes.

Radiocarbon ages of lacustrine deposits in volcanic sequences of the Lomas Coloradas area, Socorro Island, Mexico

NASA Technical Reports Server (NTRS)

Farmer, J. D.; Farmer, M. C.; Berger, R.

1993-01-01

Extensive eruptions of alkalic basalt from low-elevation fissures and vents on the southern flank of the dormant volcano, Cerro Evermann, accompanied the most recent phase of volcanic activity on Socorro Island, and created the Lomas Coloradas, a broad, gently sloping terrain comprising the southern part of the island. We obtained 14C ages of 4690 +/- 270 BP (5000-5700 cal BP) and 5040 +/- 460 BP (5300-6300 cal BP) from lacustrine deposits that occur within volcanic sequences of the lower Lomas Coloradas. Apparently, the sediments accumulated within a topographic depression between two scoria cones shortly after they formed. The lacrustine environment was destroyed when the cones were breached by headward erosion of adjacent stream drainages. This was followed by the eruption of a thin basaltic flow from fissures near the base of the northernmost cone. The flow moved downslope for a short distance and into the drainages that presently bound the study area on the east and west. The flow postdates development of the present drainage system and may be very recent. Our 14C data, along with historical accounts of volcanic activity over the last century, including submarine eruptions that occurred a few km west of Socorro in early 1993, underscore the high risk for explosive volcanism in this region and the need for a detailed volcanic hazards plan and seismic monitoring.

Lacustrine lignin biomarker record reveals a severe drought during the late Younger Dryas in southern Taiwan

NASA Astrophysics Data System (ADS)

Ding, Xiaodong; Bao, Hongyan; Zheng, Liwei; Li, Dawei; Kao, Shuh-Ji

2017-03-01

The Younger Dryas (YD) event, which punctuated the last glacial-Holocene transition period and had a profound impact on global climate, is the most well studied millennial-scale climate event although the triggering mechanism remains debate. Weakened Asian summer monsoon during the YD is recorded in oxygen isotopes of stalagmite from Mainland China. However, lacustrine climate record of the YD event has not been reported from the subtropical land-ocean boundary of the Asian continent near the Pacific warm pool. We provide a lignin biomarker record covering the last deglaciation and early Holocene (17-9 ka BP) from the Dongyuan Lake, southern Taiwan, located at the frontal zone of typhoon invasion. The lignin phenol ratio S/V shows that the vegetation in the catchments had shifted from gymnosperm dominant to angiosperm dominant plants since 12.2 ka BP. Significantly decreased lignin concentrations (TLP and λ8) and elevated lignin degradation parameters ((Ad/Al)v, P/(V + S), DHBA/V) in combination with other organic proxies (TOC, δ13Corg) during the late YD suggest a severe drought had occurred in southern Taiwan during this specific period. Changes in the lignin proxies from the Dongyuan Lake lagged the climate changes registered in stalagmite records by around 500-800 years, suggesting a slow response of vegetation and soil processes to rapid climate changes.

Final Report for the “WSU Neutron Capture Therapy Facility Support”

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerald E. Tripard; Keith G. Fox

2006-08-24

The objective for the cooperative research program for which this report has been written was to provide separate NCT facility user support for the students, faculty and scientists who would be doing the U.S. Department of Energy Office (DOE) of Science supported advanced radiotargeted research at the WSU 1 megawatt TRIGA reactor. The participants were the Idaho National laboratory (INL, P.I., Dave Nigg), the Veterinary Medical Research Center of Washington State University (WSU, Janean Fidel and Patrick Gavin), and the Washington State University Nuclear Radiation Center (WSU, P.I., Gerald Tripard). A significant number of DOE supported modifications were made tomore » the WSU reactor in order to create an epithermal neutron beam while at the same time maintaining the other activities of the 1 MW reactor. These modifications were: (1) Removal of the old thermal column. (2) Construction and insertion of a new epithermal filter, collimator and shield. (3) Construction of a shielded room that could accommodate the very high radiation field created by an intense neutron beam. (4) Removal of the previous reactor core fuel cluster arrangement. (5) Design and loading of the new reactor core fuel cluster arrangement in order to optimize the neutron flux entering the epithermal neutron filter. (6) The integration of the shielded rooms interlocks and radiological controls into the SCRAM chain and operating electronics of the reactor. (7) Construction of a motorized mechanism for moving and remotely controlling the position of the entire reactor bridge. (8) The integration of the reactor bridge control electronics into the SCRAM chain and operating electronics of the reactor. (9) The design, construction and attachment to the support structure of the reactor of an irradiation box that could be inserted into position next to the face of the reactor. (Necessitated by the previously mentioned core rearrangement). All of the above modifications were successfully completed and

Si-depleted outer core inferred from sound velocity measurements of liquid Fe-Si alloys

NASA Astrophysics Data System (ADS)

Nakajima, Y.; Imada, S.; Hirose, K.; Kuwayama, Y.; Sinmyo, R.; Tateno, S.; Ozawa, H.; Tsutsui, S.; Uchiyama, H.; Baron, A. Q. R.

2016-12-01

Recent core formation models [1,2] suggested that a large amount of Si could have been incorporated into the core forming metals in the early stage of the Earth. These studies gave estimates for the Si content in the core, from 2 to 9 wt.%. In order to constrain the Si content of the outer core, we have determined the sound wave velocity of liquid Fe-Si alloys under high pressures and high temperatures. Starting materials of Fe-Si alloys with 6.5 and 9 wt.% Si were melted in a laser-heated diamond-anvil cell. The longitudinal acoustic phonon excitation of a liquid metal was measured up to 52 GPa and 3200 K by using high resolution inelastic X-ray scattering spectroscopy at beamline BL35XU [3] of the SPring-8 synchrotron facility. Our results show that silicon significantly increases the P-wave velocity of liquid Fe. Seismological observation shows that the P-wave velocity in the outer core is 3-4% faster than in pure iron. Comparing the present results with seismological observations, the silicon content of the outer core should be limited to be <2 wt.%, significantly lower than previous estimates based on the element partitioning between core forming mental and silicate magma ocean during core formation processes. This indicates that the present-day core is depleted in Si relative to the ancient core just after core formation, which agrees with the recent proposal [4] that the Si content in the outer core has been diminished by SiO2 crystallization through the core cooling history. [1] Rubie et al. (2011) Earth Planet. Sci. Lett. 301, 31-42. [2] Siebert et al. (2013) Science 339, 1194-1197. [3] Baron et al. (2000) J. Phys. Chem. Solids 61, 461-465 [4] Hirose et al. (2015) Abstract presented at AGU Fall Meeting 2015.

Space Station Furnace Facility. Volume 2: Requirements definition and conceptual design study

NASA Technical Reports Server (NTRS)

1992-01-01

The Space Station Freedom Furnace (SSFF) Project is divided into two phases: phase 1, a definition study phase, and phase 2, a design and development phase. TBE was awarded a research study entitled, 'Space Station Furnace Facility Requirements Definition and Conceptual Design Study' on June 2, 1989. This report addresses the definition study phase only. Phase 2 is to be complete after completion of phase 1. The contract encompassed a requirements definition study and culminated in hardware/facility conceptual designs and hardware demonstration development models to test these conceptual designs. The study was divided into two parts. Part 1 (the basic part of the effort) encompassed preliminary requirements definition and assessment; conceptional design of the SSFF Core; fabrication of mockups; and preparation for the support of a conceptional design review (CoDR). Part 2 (the optional part of the effort) included detailed definition of the engineering and design requirements, as derived from the science requirements; refinement of the conceptual design of the SSFF Core; fabrication and testing of the 'breadboards' or development models; and preparation for and support of a requirements definition review.

Assessment of the core and support functions of the Integrated Disease Surveillance system in Maharashtra, India

PubMed Central

2013-01-01

Background Monitoring the progress of the Integrated Disease Surveillance (IDS) strategy is an important component to ensure its sustainability in the state of Maharashtra in India. The purpose of the study was to document the baseline performance of the system on its core and support functions and to understand the challenges for its transition from an externally funded “project” to a state owned surveillance “program”. Methods Multi-centre, retrospective cross-sectional evaluation study to assess the structure, core and support surveillance functions using modified WHO generic questionnaires. All 34 districts in the state and randomly identified 46 facilities and 25 labs were included in the study. Results Case definitions were rarely used at the periphery. Limited laboratory capacity at all levels compromised case and outbreak confirmation. Only 53% districts could confirm all priority diseases. Stool sample processing was the weakest at the periphery. Availability of transport media, trained staff, and rapid diagnostic tests were main challenges at the periphery. Data analysis was weak at both district and facility levels. Outbreak thresholds were better understood at facility level (59%) than at the district (18%). None of the outbreak indicator targets were met and submission of final outbreak report was the weakest. Feedback and training was significantly better (p < 0.0001) at district level (65%; 76%) than at facility level (15%; 37%). Supervision was better at the facility level (37%) than at district (18%) and so were coordination, communication and logistic resources. Contractual part time positions, administrative delays in recruitment, and vacancies (30%) were main human resource issues that hampered system performance. Conclusions Significant progress has been made in the core and support surveillance functions in Maharashtra, however some challenges exist. Support functions (laboratory, transport and communication equipment, training

34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

34. DESPATCH CORE OVENS, GREY IRON FOUNDRY CORE ROOM, BAKES CORES THAT ARE NOT MADE ON HEATED OR COLD BOX CORE MACHINES, TO SET BINDING AGENTS MIXED WITH THE SAND CREATING CORES HARD ENOUGH TO WITHSTAND THE FLOW OF MOLTEN IRON INSIDE A MOLD. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

Mesoporous activated carbon from corn stalk core for lithium ion batteries

NASA Astrophysics Data System (ADS)

Li, Yi; Li, Chun; Qi, Hui; Yu, Kaifeng; Liang, Ce

2018-04-01

A novel mesoporous activated carbon (AC) derived from corn stalk core is prepared via a facile and effective method which including the decomposition and carbonization of corn stalk core under an inert gas atmosphere and further activation process with KOH solution. The mesoporous activated carbon (AC) is characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) measurements. These biomass waste derived from activated carbon is proved to be promising anode materials for high specific capacity lithium ion batteries. The activated carbon anode possesses excellent reversible capacity of 504 mAh g-1 after 100 cycles at 0.2C. Compared with the unactivated carbon (UAC), the electrochemical performance of activated carbon is significantly improved due to its mesoporous structure.

Facile synthesis of core-shell Cu2O@ ZnO structure with enhanced photocatalytic H2 production

NASA Astrophysics Data System (ADS)

Zhang, Yong-Hui; Jiu, Bei-Bei; Gong, Fei-Long; Lu, Kuan; Jiang, Nan; Zhang, Hao-Li; Chen, Jun-Li

2018-05-01

Core-shell Cu2O@ZnO composites were synthesized successfully based on a one-pot hydrothermal method in the presence of dioctyl sulfosuccinate sodium salt (AOT) surfactant. The Cu2O can be converted to rough core-shell Cu2O@ZnO structure by adjusting the amount of zinc powder added. The as-synthesized Cu2O@ZnO composites exhibited excellent photocatalytic activity and the amount of H2 generated using these composites was 4.5-fold more than that produced with Cu2O cubes. A possible photocatalytic mechanism for the Cu2O@ZnO composites with enhanced photocatalytic activity could be the separation by ZnO of the effective charge carriers.

Magnetic resonance imaging in laboratory petrophysical core analysis

NASA Astrophysics Data System (ADS)

Mitchell, J.; Chandrasekera, T. C.; Holland, D. J.; Gladden, L. F.; Fordham, E. J.

2013-05-01

Magnetic resonance imaging (MRI) is a well-known technique in medical diagnosis and materials science. In the more specialized arena of laboratory-scale petrophysical rock core analysis, the role of MRI has undergone a substantial change in focus over the last three decades. Initially, alongside the continual drive to exploit higher magnetic field strengths in MRI applications for medicine and chemistry, the same trend was followed in core analysis. However, the spatial resolution achievable in heterogeneous porous media is inherently limited due to the magnetic susceptibility contrast between solid and fluid. As a result, imaging resolution at the length-scale of typical pore diameters is not practical and so MRI of core-plugs has often been viewed as an inappropriate use of expensive magnetic resonance facilities. Recently, there has been a paradigm shift in the use of MRI in laboratory-scale core analysis. The focus is now on acquiring data in the laboratory that are directly comparable to data obtained from magnetic resonance well-logging tools (i.e., a common physics of measurement). To maintain consistency with well-logging instrumentation, it is desirable to measure distributions of transverse (T2) relaxation time-the industry-standard metric in well-logging-at the laboratory-scale. These T2 distributions can be spatially resolved over the length of a core-plug. The use of low-field magnets in the laboratory environment is optimal for core analysis not only because the magnetic field strength is closer to that of well-logging tools, but also because the magnetic susceptibility contrast is minimized, allowing the acquisition of quantitative image voxel (or pixel) intensities that are directly scalable to liquid volume. Beyond simple determination of macroscopic rock heterogeneity, it is possible to utilize the spatial resolution for monitoring forced displacement of oil by water or chemical agents, determining capillary pressure curves, and estimating

Core Formation Process and Light Elements in the Planetary Core

NASA Astrophysics Data System (ADS)

Ohtani, E.; Sakairi, T.; Watanabe, K.; Kamada, S.; Sakamaki, T.; Hirao, N.

2015-12-01

Si, O, and S are major candidates for light elements in the planetary core. In the early stage of the planetary formation, the core formation started by percolation of the metallic liquid though silicate matrix because Fe-S-O and Fe-S-Si eutectic temperatures are significantly lower than the solidus of the silicates. Therefore, in the early stage of accretion of the planets, the eutectic liquid with S enrichment was formed and separated into the core by percolation. The major light element in the core at this stage will be sulfur. The internal pressure and temperature increased with the growth of the planets, and the metal component depleted in S was molten. The metallic melt contained both Si and O at high pressure in the deep magma ocean in the later stage. Thus, the core contains S, Si, and O in this stage of core formation. Partitioning experiments between solid and liquid metals indicate that S is partitioned into the liquid metal, whereas O is weakly into the liquid. Partitioning of Si changes with the metallic iron phases, i.e., fcc iron-alloy coexisting with the metallic liquid below 30 GPa is depleted in Si. Whereas hcp-Fe alloy above 30 GPa coexisting with the liquid favors Si. This contrast of Si partitioning provides remarkable difference in compositions of the solid inner core and liquid outer core among different terrestrial planets. Our melting experiments of the Fe-S-Si and Fe-O-S systems at high pressure indicate the core-adiabats in small planets, Mercury and Mars, are greater than the slope of the solidus and liquidus curves of these systems. Thus, in these planets, the core crystallized at the top of the liquid core and 'snowing core' formation occurred during crystallization. The solid inner core is depleted in both Si and S whereas the liquid outer core is relatively enriched in Si and S in these planets. On the other hand, the core adiabats in large planets, Earth and Venus, are smaller than the solidus and liquidus curves of the systems. The

Extraction and speciation of arsenic in lacustrine sediments

USGS Publications Warehouse

Ficklin, W.H.

1990-01-01

Arsenic was partially extracted with 4.OM hydrochloric acid, from samples collected at 25-cm intervals in a 350-cm column of sediment at Milltown Reservoir, Montana and from a 60-cm core of sediment collected at the Cheyenne River Embayment of Lake Oahe, South Dakota. The sediment in both reservoirs is highly contaminated with arsenic. The extracted arsenic was separated into As(III) and As(V) on acetate form Dowex 1-X8 ion-exchange resin with 0.12M HCl eluent. Residual arsenic was sequentially extracted with KClO3 and HCl. Arsenic was determined by graphite-furnace atomic-absorption spectrometry. The analytical results define oxidized and reduced zones in the sediment columns. ?? 1990.

How cores grow by pebble accretion. I. Direct core growth

NASA Astrophysics Data System (ADS)

Brouwers, M. G.; Vazan, A.; Ormel, C. W.

2018-03-01

Context. Planet formation by pebble accretion is an alternative to planetesimal-driven core accretion. In this scenario, planets grow by the accretion of cm- to m-sized pebbles instead of km-sized planetesimals. One of the main differences with planetesimal-driven core accretion is the increased thermal ablation experienced by pebbles. This can provide early enrichment to the planet's envelope, which influences its subsequent evolution and changes the process of core growth. Aims: We aim to predict core masses and envelope compositions of planets that form by pebble accretion and compare mass deposition of pebbles to planetesimals. Specifically, we calculate the core mass where pebbles completely evaporate and are absorbed before reaching the core, which signifies the end of direct core growth. Methods: We model the early growth of a protoplanet by calculating the structure of its envelope, taking into account the fate of impacting pebbles or planetesimals. The region where high-Z material can exist in vapor form is determined by the temperature-dependent vapor pressure. We include enrichment effects by locally modifying the mean molecular weight of the envelope. Results: In the pebble case, three phases of core growth can be identified. In the first phase (Mcore < 0.23-0.39 M⊕), pebbles impact the core without significant ablation. During the second phase (Mcore < 0.5M⊕), ablation becomes increasingly severe. A layer of high-Z vapor starts to form around the core that absorbs a small fraction of the ablated mass. The rest of the material either rains out to the core or instead mixes outwards, slowing core growth. In the third phase (Mcore > 0.5M⊕), the high-Z inner region expands outwards, absorbing an increasing fraction of the ablated material as vapor. Rainout ends before the core mass reaches 0.6 M⊕, terminating direct core growth. In the case of icy H2O pebbles, this happens before 0.1 M⊕. Conclusions: Our results indicate that pebble accretion can

Experimental and code simulation of a station blackout scenario for APR1400 with test facility ATLAS and MARS code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, X. G.; Kim, Y. S.; Choi, K. Y.

2012-07-01

A SBO (station blackout) experiment named SBO-01 was performed at full-pressure IET (Integral Effect Test) facility ATLAS (Advanced Test Loop for Accident Simulation) which is scaled down from the APR1400 (Advanced Power Reactor 1400 MWe). In this study, the transient of SBO-01 is discussed and is subdivided into three phases: the SG fluid loss phase, the RCS fluid loss phase, and the core coolant depletion and core heatup phase. In addition, the typical phenomena in SBO-01 test - SG dryout, natural circulation, core coolant boiling, the PRZ full, core heat-up - are identified. Furthermore, the SBO-01 test is reproduced bymore » the MARS code calculation with the ATLAS model which represents the ATLAS test facility. The experimental and calculated transients are then compared and discussed. The comparison reveals there was malfunction of equipments: the SG leakage through SG MSSV and the measurement error of loop flow meter. As the ATLAS model is validated against the experimental results, it can be further employed to investigate the other possible SBO scenarios and to study the scaling distortions in the ATLAS. (authors)« less

Pre-aged plant waxes in tropical lake sediments and their influence on the chronology of molecular paleoclimate proxy records

NASA Astrophysics Data System (ADS)

Douglas, Peter M. J.; Pagani, Mark; Eglinton, Timothy I.; Brenner, Mark; Hodell, David A.; Curtis, Jason H.; Ma, Keith F.; Breckenridge, Andy

2014-09-01

Sedimentary records of plant-wax hydrogen (δDwax) and carbon (δ13Cwax) stable isotopes are increasingly applied to infer past climate change. Compound-specific radiocarbon analyses, however, indicate that long time lags can occur between the synthesis of plant waxes and their subsequent deposition in marginal marine sediments. The influence of these time lags on interpretations of plant-wax stable isotope records is presently unconstrained, and it is unclear whether such time lags also affect lacustrine sediments. We present compound-specific radiocarbon (14Cwax) data for n-alkanoic acid plant waxes (n-C26 to n-C32) from: (1) a sediment core from Lake Chichancanab, Yucatan Peninsula, Mexico, (2) soils in the Lake Chichancanab catchment, and (3) surface sediments from three other lakes in southeastern Mexico and northern Guatemala. 14Cwax ages in the surface sediments are consistently older than modern, and may be negatively correlated with mean annual precipitation and positively correlated with lake catchment area. 14Cwax ages in soils surrounding Lake Chichancanab increase with soil depth, consistent with deep, subsoil horizons being the primary source of lacustrine aged plant waxes, which are likely delivered to lake sediments through subsurface transport. Plant waxes in the Lake Chichancanab core are 350-1200 years older than corresponding ages of bulk sediment deposition, determined by 14C dates on terrestrial plant macrofossils in the core. A δDwax time series is in closer agreement with other regional proxy hydroclimate records when a plant-wax 14C age model is applied, as opposed to the macrofossil-based core chronology. Inverse modeling of plant-wax age distribution parameters suggests that plant waxes in the Lake Chichancanab sediment core derive predominantly from millennial-age soil carbon pools that exhibit relatively little age variance (<200 years). Our findings demonstrate that high-temporal-resolution climate records inferred from stable isotope

23. CORE WORKER OPERATING A COREBLOWER THAT PNEUMATICALLY FILLED CORE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. CORE WORKER OPERATING A CORE-BLOWER THAT PNEUMATICALLY FILLED CORE BOXES WITH RESIGN IMPREGNATED SAND AND CREATED A CORE THAT THEN REQUIRED BAKING, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

Complete Au@ZnO core-shell nanoparticles with enhanced plasmonic absorption enabling significantly improved photocatalysis

NASA Astrophysics Data System (ADS)

Sun, Yiqiang; Sun, Yugang; Zhang, Tao; Chen, Guozhu; Zhang, Fengshou; Liu, Dilong; Cai, Weiping; Li, Yue; Yang, Xianfeng; Li, Cuncheng

2016-05-01

Nanostructured ZnO exhibits high chemical stability and unique optical properties, representing a promising candidate among photocatalysts in the field of environmental remediation and solar energy conversion. However, ZnO only absorbs the UV light, which accounts for less than 5% of total solar irradiation, significantly limiting its applications. In this article, we report a facile and efficient approach to overcome the poor wettability between ZnO and Au by carefully modulating the surface charge density on Au nanoparticles (NPs), enabling rapid synthesis of Au@ZnO core-shell NPs at room temperature. The resulting Au@ZnO core-shell NPs exhibit a significantly enhanced plasmonic absorption in the visible range due to the Au NP cores. They also show a significantly improved photocatalytic performance in comparison with their single-component counterparts, i.e., the Au NPs and ZnO NPs. Moreover, the high catalytic activity of the as-synthesized Au@ZnO core-shell NPs can be maintained even after many cycles of photocatalytic reaction. Our results shed light on the fact that the Au@ZnO core-shell NPs represent a promising class of candidates for applications in plasmonics, surface-enhanced spectroscopy, light harvest devices, solar energy conversion, and degradation of organic pollutants.Nanostructured ZnO exhibits high chemical stability and unique optical properties, representing a promising candidate among photocatalysts in the field of environmental remediation and solar energy conversion. However, ZnO only absorbs the UV light, which accounts for less than 5% of total solar irradiation, significantly limiting its applications. In this article, we report a facile and efficient approach to overcome the poor wettability between ZnO and Au by carefully modulating the surface charge density on Au nanoparticles (NPs), enabling rapid synthesis of Au@ZnO core-shell NPs at room temperature. The resulting Au@ZnO core-shell NPs exhibit a significantly enhanced plasmonic

Dating sediment cores from Hudson River marshes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robideau, R.; Bopp, R.F.

1993-03-01

There are several methods for determining sediment accumulation rates in the Hudson River estuary. One involves the analysis of the concentration of certain radionuclides in sediment core sections. Radionuclides occur in the Hudson River as a result of: natural sources, fallout from nuclear weapons testing and low level aqueous releases from the Indian Point Nuclear Power Facility. The following radionuclides have been studied in the authors work: Cesium-137, which is derived from global fallout that started in the 1950's and has peaked in 1963. Beryllium-7, a natural radionuclide with a 53 day half-life and found associated with very recently depositedmore » sediments. Another useful natural radionuclide is Lead-210 derived from the decay of Radon-222 in the atmosphere. Lead-210 has a half-life of 22 years and can be used to date sediments up to about 100 years old. In the Hudson River, Cobalt-60 is a marker for Indian Point Nuclear Reactor discharges. The author's research involved taking sediment core samples from four sites in the Hudson River Estuarine Research Reserve areas. These core samples were sectioned, dried, ground and analyzed for the presence of radionuclides by the method of gamma-ray spectroscopy. The strength of each current pulse is proportional to the energy level of the gamma ray absorbed. Since different radionuclides produce gamma rays of different energies, several radionuclides can be analyzed simultaneously in each of the samples. The data obtained from this research will be compared to earlier work to obtain a complete chronology of sediment deposition in these Reserve areas of the river. Core samples may then by analyzed for the presence of PCB's, heavy metals and other pollutants such as pesticides to construct a pollution history of the river.« less

Core-Cutoff Tool

NASA Technical Reports Server (NTRS)

Gheen, Darrell

2007-01-01

A tool makes a cut perpendicular to the cylindrical axis of a core hole at a predetermined depth to free the core at that depth. The tool does not damage the surrounding material from which the core was cut, and it operates within the core-hole kerf. Coring usually begins with use of a hole saw or a hollow cylindrical abrasive cutting tool to make an annular hole that leaves the core (sometimes called the plug ) in place. In this approach to coring as practiced heretofore, the core is removed forcibly in a manner chosen to shear the core, preferably at or near the greatest depth of the core hole. Unfortunately, such forcible removal often damages both the core and the surrounding material (see Figure 1). In an alternative prior approach, especially applicable to toxic or fragile material, a core is formed and freed by means of milling operations that generate much material waste. In contrast, the present tool eliminates the damage associated with the hole-saw approach and reduces the extent of milling operations (and, hence, reduces the waste) associated with the milling approach. The present tool (see Figure 2) includes an inner sleeve and an outer sleeve and resembles the hollow cylindrical tool used to cut the core hole. The sleeves are thin enough that this tool fits within the kerf of the core hole. The inner sleeve is attached to a shaft that, in turn, can be attached to a drill motor or handle for turning the tool. This tool also includes a cutting wire attached to the distal ends of both sleeves. The cutting wire is long enough that with sufficient relative rotation of the inner and outer sleeves, the wire can cut all the way to the center of the core. The tool is inserted in the kerf until its distal end is seated at the full depth. The inner sleeve is then turned. During turning, frictional drag on the outer core pulls the cutting wire into contact with the core. The cutting force of the wire against the core increases with the tension in the wire and

Explosion symmetry improvement of polyimide-coated tungsten wire in vacuum on negative discharge facility

NASA Astrophysics Data System (ADS)

Li, Mo; Wu, Jian; Lu, Yihan; Li, Xingwen; Li, Yang; Qiu, Mengtong

2018-01-01

Tungsten wire explosion is very asymmetric when fast current rate and insulated coatings are both applied on negative discharge facility using a 24-mm-diameter cathode geometry, which is commonly used on mega-ampere facilities. It is inferred, based on an analytical treatment of the guiding center drift and COMSOL simulations, that the large negative radial electric field causes early voltage breakdown and terminates energy deposition into the wire core on the anode side of the wire. After the anode side is short circuited, the radial electric field along the wire surface on the cathode side will change its polarity and thus leading to additional energy deposition into the wire core. This change causes ˜10 times larger energy deposition and ˜14 times faster explosion velocity in the cathode side than the anode side. In order to reduce this asymmetry, a hollow cylindrical cathode geometry was used to reverse the polarity of radial electric field and was optimized to use on multi-MA facilities. In this case, fully vaporized polyimide-coated tungsten wire with great symmetry improvement was achieved with energy deposition of ˜8.8 eV/atom. The atomic and electronic density distributions for the two different load geometries were obtained by the double-wavelength measurement.

Temporal Change of Seismic Earth's Inner Core Phases: Inner Core Differential Rotation Or Temporal Change of Inner Core Surface?

NASA Astrophysics Data System (ADS)

Yao, J.; Tian, D.; Sun, L.; Wen, L.

2017-12-01

Since Song and Richards [1996] first reported seismic evidence for temporal change of PKIKP wave (a compressional wave refracted in the inner core) and proposed inner core differential rotation as its explanation, it has generated enormous interests in the scientific community and the public, and has motivated many studies on the implications of the inner core differential rotation. However, since Wen [2006] reported seismic evidence for temporal change of PKiKP wave (a compressional wave reflected from the inner core boundary) that requires temporal change of inner core surface, both interpretations for the temporal change of inner core phases have existed, i.e., inner core rotation and temporal change of inner core surface. In this study, we discuss the issue of the interpretation of the observed temporal changes of those inner core phases and conclude that inner core differential rotation is not only not required but also in contradiction with three lines of seismic evidence from global repeating earthquakes. Firstly, inner core differential rotation provides an implausible explanation for a disappearing inner core scatterer between a doublet in South Sandwich Islands (SSI), which is located to be beneath northern Brazil based on PKIKP and PKiKP coda waves of the earlier event of the doublet. Secondly, temporal change of PKIKP and its coda waves among a cluster in SSI is inconsistent with the interpretation of inner core differential rotation, with one set of the data requiring inner core rotation and the other requiring non-rotation. Thirdly, it's not reasonable to invoke inner core differential rotation to explain travel time change of PKiKP waves in a very small time scale (several months), which is observed for repeating earthquakes in Middle America subduction zone. On the other hand, temporal change of inner core surface could provide a consistent explanation for all the observed temporal changes of PKIKP and PKiKP and their coda waves. We conclude that

Role of Sports Facilities in the Process of Revitalization of Brownfields

NASA Astrophysics Data System (ADS)

Taraszkiewicz, Karolina; Nyka, Lucyna

2017-10-01

The paper gives an evidence that building a large sports facility can generate beneficial urban space transformation and a significant improvement in the dilapidated urban areas. On the basis of theoretical investigations and case studies it can be proved that sports facilities introduced to urban brownfields could be considered one of the best known large scale revitalization methods. Large urban spaces surrounding sport facilities such as stadiums and other sports arenas create excellent conditions for designing additional recreational function, such as parks and other green areas. Since sports venues are very often located on brownfields and post-industrial spaces, there are usually well related with canals, rivers and other water routes or reservoirs. Such spaces become attractors for large groups of people. This, in effect initiate the process of introducing housing estates to the area and gradually the development of multifunctional urban structure. As research shows such process of favourable urban transformation could be based on implementing several important preconditions. One of the most significant one is the formation of the new communication infrastructure, which links newly formed territories with the well-structured urban core. Well planned program of the new sports facilities is also a very important factor. As research shows multifunctional large sports venues may function in the city as a new kind of public space that stimulates new genres of social relations, offers entertainment and free time activities, not necessarily related with sport. This finally leads to the creation of new jobs and more general improvement of a widely understood image of the district, growing appreciation for the emerging new location and consequently new investments in the neighbouring areas. The research gives new evidence to the ongoing discussion on the drawbacks and benefits of placing stadiums and sports arenas in the urban core.

Enhanced bioactivity of internally functionalized cationic dendrimers with PEG cores

PubMed Central

Albertazzi, Lorenzo; Mickler, Frauke M.; Pavan, Giovanni M.; Salomone, Fabrizio; Bardi, Giuseppe; Panniello, Mariangela; Amir, Elizabeth; Kang, Taegon; Killops, Kato L.; Bräuchle, Christoph; Amir, Roey J.; Hawker, Craig J.

2012-01-01

Hybrid dendritic-linear block copolymers based on a 4-arm polyethylene glycol (PEG) core were synthesized using an accelerated AB2/CD2 dendritic growth approach through orthogonal amine/epoxy and thiol-yne chemistries. The biological activity of these 4-arm and the corresponding 2-arm hybrid dendrimers revealed an enhanced, dendritic effect with an exponential increase in cell internalization concomitant with increasing amine end-groups and low cytotoxicity. Furthermore, the ability of these hybrid dendrimers to induce endosomal escape combined with their facile and efficient synthesis makes them attractive platforms for gene transfection. The 4-arm-based dendrimer showed significantly improved DNA binding and gene transfection capabilities in comparison with the 2-arm derivative. These results combined with the MD simulation indicate a significant effect of both the topology of the PEG core and the multivalency of these hybrid macromolecules, on their DNA binding and delivery capablities. PMID:23140570

Initial Continuous Chemistry Results From The Roosevelt Island Ice Core (RICE)

NASA Astrophysics Data System (ADS)

Kjær, H. A.; Vallelonga, P. T.; Simonsen, M. F.; Neff, P. D.; Bertler, N. A. N.; Svensson, A.; Dahl-Jensen, D.

2014-12-01

The Roosevelt Island ice core (79.36° S, -161.71° W) was drilled in 2011-13 at the top of the Roosevelt Island ice dome, a location surrounded by the Ross ice shelf. The RICE ice core provides a unique opportunity to look into the past evolution of the West Antarctic Ice sheet. Further the site has high accumulation; 0.26 m of ice equivalent is deposited annually allowing annual layer determination for many chemical parameters. The RICE core was drilled to bedrock and has a total length of 763 metres. Preliminary results derived from water isotopes suggest that the oldest ice reaches back to the Eemian, with the last glacial being compressed in the bottom 60 metres. We present preliminary results from the RICE ice core including continuous measurements of acidity using an optical dye method, insoluble dust particles, conductivity and calcium. The core was analyzed at the New Zealand National Ice Core Research Facility at GNS Science in Wellington. The analytical set up used to determine climate proxies in the ice core was a modified version of the Copenhagen CFA system (Bigler et al., 2011). Key volcanic layers have been matched to those from the WAIS record (Sigl et al., 2013). A significant anti-correlation between acidity and calcium was seen in the Holocene part of the record. Due to the proximity to the ocean a large fraction of the calcium originates from sea salt and is in phase with total conductivity and sodium. In combination with the insoluble dust record, calcium has been apportioned into ocean-related and dust-related sources. Variability over the Holocene is presented and attributed to changing inputs of marine and dust aerosols.

Louisiana Governor John Bel Edwards Tours NASA Michoud Assembly Facility

NASA Image and Video Library

2017-11-01

This B-roll video shows Louisiana Gov. John Bel Edwards when visited NASA’s Michoud Assembly Facility in New Orleans on Nov. 1, 2017. He spoke about the state’s partnerships with NASA and the 20 companies and government agencies located at the facility. He toured Michoud with Todd May, the director of NASA’s Marshall Space Flight Center, which manages Michoud. NASA is building its new deep space rocket, the Space Launch System (SLS), and the Orion spacecraft at Michoud. New Orleans Mayor Mitch Landrieu and Michoud Director Keith Hefner, along with members of the Louisiana Economic Development accompanied the Edwards and May on the tour. They saw the Vertical Assemby Center where large structures of the SLS core stage are welded.

Commissioning for the European XFEL facility

NASA Astrophysics Data System (ADS)

Nölle, D.

2017-06-01

The European XFEL is a 4th generation light source based on the Self Amplified Spontaneous Emission (SASE) FreeElectron-Laser concept. It is currently being commissioned in North- Germany. The core installation is a 17.5 GeV superconducting accelerator driving 3 SASE lines with photon energies from 1 to beyond 20 keV range with a maximum of 27.000 pulses per second. The international facility is organized as a limited liability company with shareholders from the contributing countries. DESY has taken over the leadership of the accelerator construction consortium, and will be in charge of the operation of the accelerator complex. The facility was set up with contributions from the 11 shareholder countries, either being hardware systems and/or staff or cash contributions. The construction is almost complete, and the commissioning phase has started by the end of 2015. This contribution will report the status of the accelerator complex with emphasis on the commissioning of the accelerator and an outlook to the commissioning of the SASE 1 FEL line.

Complex Inner Core of the Earth

NASA Astrophysics Data System (ADS)

Tkalcic, H.; Pachhai, S.; Tanaka, S.; Mattesini, M.; Stephenson, J.

2015-12-01

Recent studies have revealed an increasingly complex structure of the Earth's inner core (IC) in properties such as seismic velocity, attenuation, anisotropy, and differential rotation. In addition, the inner core boundary (ICB) has proven to be more complex than just a dividing boundary between the liquid outer core and the solid IC. On one hand, these advancements have been achieved due to the availability of new data. On the other hand, this is due to better computational facilities, the introduction of new mathematical techniques to this field of study, and a multidisciplinary approach. Through first principles treatment of global seismological differential travel time data, it is possible to acquire a complex mineralogical structure of the IC, consisting of at least three different phases of iron. This has the potential to unify seismological observations and interpretation of IC anisotropy with mineral physics and recent geodynamical scenarios suggesting a predominant degree 1 structure in the IC, although a new complexity emerges from recent attenuation and isotropic velocity studies. A number of studies have recently shown lateral variability of these properties in the uppermost IC, to an increasingly more complex extent than a simple harmonic degree 1. While large earthquakes recorded on individual stations constrain established ray-path corridors through the IC, large arrays provide an unprecedented and overwhelming number of deep Earth-sensitive data. For example, the most complete collection of empirical travel time curves of core phases, from simultaneous recordings of a distant individual earthquake on hundreds of stations is now within reach. Similarly, we can recover hundreds of simultaneous observations of PKiKP and PcP waves from more proximate earthquakes. Traditionally, these have been used to study the sharpness of the ICB by a far more modest number of data points in the time domain. A new study of these observations in the frequency domain

Arc-Heater Facility for Hot Hydrogen Exposure of Nuclear Thermal Rocket Materials

NASA Technical Reports Server (NTRS)

Litchford, Ron J.; Foote, John P.; Wang,Ten-See; Hickman, Robert; Panda, Binayak; Dobson, Chris; Osborne, Robin; Clifton, Scooter

2006-01-01

A hyper-thermal environment simulator is described for hot hydrogen exposure of nuclear thermal rocket material specimens and component development. This newly established testing capability uses a high-power, multi-gas, segmented arc-heater to produce high-temperature pressurized hydrogen flows representative of practical reactor core environments and is intended to serve. as a low cost test facility for the purpose of investigating and characterizing candidate fueUstructura1 materials and improving associated processing/fabrication techniques. Design and development efforts are thoroughly summarized, including thermal hydraulics analysis and simulation results, and facility operating characteristics are reported, as determined from a series of baseline performance mapping tests.

Ultrathin TiO2 layer coated-CdS spheres core-shell nanocomposite with enhanced visible-light photoactivity.

PubMed

Chen, Zhang; Xu, Yi-Jun

2013-12-26

Development of various strategies for controllable fabrication of core-shell nanocomposites (CSNs) with highly active photocatalytic performance has been attracting ever-increasing research attention. In particular, control of the ultrathin layer TiO2 shell in constructing CSNs in an aqueous phase is a significant but technologically challenging issue. Here, this paper demonstrates the interface assembly synthesis of CdS nanospheres@TiO2 core-shell photocatalyst via the electrostatic interaction of negatively charged water-stable titania precursor with positively charged CdS nanospheres (CdS NSPs), followed by the formation of the ultrathin-layer TiO2 shell through a facile refluxing process in aqueous phase. The as-formed CdS NSPs@TiO2 core-shell nanohybrid exhibits a high visible-light-driven photoactivity for selective transformation and reduction of heavy metal ions. The ultrathin TiO2 layer coated on CdS NSPs results in excellent light transmission property, enhanced adsorption capacity, and improved transfer of charge carriers and lifespan of photoinduced electron-hole pairs, which would prominently contribute to the significant photoactivity enhancement. It is anticipated that this facile aqueous-phase synthesis strategy could be extended to design a variety of more efficient CSN photocatalysts with controllable morphology toward target applications in diverse photoredox processes.

Latest developments on fibered MOPA in mJ range with hollow-core fiber beam delivery and fiber beam shaping used as seeder for large scale laser facilities (Conference Presentation)

NASA Astrophysics Data System (ADS)

Gleyze, Jean-François; Scol, Florent; Perrin, Arnaud; Gouriou, Pierre; Valentin, Constance; Bouwmans, Géraud; Hugonnot, Emmanuel

2017-05-01

The Laser Megajoule (LMJ) is a French large scale laser facility dedicated to inertial fusion and plasma physics research. LMJ front-ends are based on fiber laser technology at nanojoule range [1]. Scaling the energy of those fiber seeders to the millijoule range is a way to upgrade LMJ's front ends architecture and could also be used as seeder for lasers for ELI project for example. However, required performances are so restrictive (optical-signal-to-noise ratio higher than 50 dB, temporally-shaped nanosecond pulses and spatial single-mode top-hat beam output) that such fiber systems are very tricky to build. High-energy fiber amplifiers In 2015, we have demonstrated, an all-fiber MOPA prototype able to produce a millijoule seeder, but unfortunately not 100% conform for all LMJ's performances. A major difficulty was to manage the frequency modulation used to avoid stimulated Brillouin scattering, to amplitude modulation (FM-AM) conversion, this limits the energy at 170µJ. For upgrading the energy to the millijoule range, it's necessary to use an amplifier with a larger core fiber. However, this fiber must still be flexible; polarization maintaining and exhibit a strictly single-mode behaviour. We are thus developing a new amplifier architecture based on an Yb-doped tapered fiber: its core diameter is from a narrow input to a wide output (MFD 8 to 26 µm). A S² measurement on a 2,5m long tapered fiber rolled-up on 22 cm diameter confirmed that this original geometry allows obtaining strictly single-mode behaviour. In a 1 kHz repetition rate regime, we already obtain 750 µJ pulses, and we are on the way to mJ, respecting LMJ performances. Beam delivery In LMJ architecture the distance between the nanojoule fiber seeder and the amplifier stages is about 16 m. Beam delivery is achieved with a standard PM fiber, such a solution is no longer achievable with hundreds of kilowatt peak powers. An efficient way to minimize nonlinear effects is to use hollow-core (HC

Heavy metal and trace elements in riparian vegetation and macrophytes associated with lacustrine systems in Northern Patagonia Andean Range.

PubMed

Juárez, Andrea; Arribére, María A; Arcagni, Marina; Williams, Natalia; Rizzo, Andrea; Ribeiro Guevara, Sergio

2016-09-01

Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections.

[Implementation of quality management in medical rehabilitation--current challenges for rehabilitation facilities].

PubMed

Enge, M; Koch, A; Müller, T; Vorländer, T

2010-12-01

The legal responsibilities imposed upon rehabilitation facilities under section 20 (2a) SGB IX, necessitate fundamental decisions to be taken regarding the development of quality management systems over and above the existing framework. This article is intended to provide ideas and suggestions to assist rehabilitation facilities in implementing a quality management system, which is required in addition to participation in the quality assurance programmes stipulated by the rehabilitation carriers. In this context, the additional internal benefit a functioning quality management system can provide for ensuring a high level of quality and for maintaining the competitiveness of the rehabilitation facility should be taken into account. The core element of these observations, hence, is a list of requirements which enables assessment of the quality of consultants' performance in setting up a quality management system. © Georg Thieme Verlag KG Stuttgart · New York.

Opportunities and Challenges of Linking Scientific Core Samples to the Geoscience Data Ecosystem

NASA Astrophysics Data System (ADS)

Noren, A. J.

2016-12-01

Core samples generated in scientific drilling and coring are critical for the advancement of the Earth Sciences. The scientific themes enabled by analysis of these samples are diverse, and include plate tectonics, ocean circulation, Earth-life system interactions (paleoclimate, paleobiology, paleoanthropology), Critical Zone processes, geothermal systems, deep biosphere, and many others, and substantial resources are invested in their collection and analysis. Linking core samples to researchers, datasets, publications, and funding agencies through registration of globally unique identifiers such as International Geo Sample Numbers (IGSNs) offers great potential for advancing several frontiers. These include maximizing sample discoverability, access, reuse, and return on investment; a means for credit to researchers; and documentation of project outputs to funding agencies. Thousands of kilometers of core samples and billions of derivative subsamples have been generated through thousands of investigators' projects, yet the vast majority of these samples are curated at only a small number of facilities. These numbers, combined with the substantial similarity in sample types, make core samples a compelling target for IGSN implementation. However, differences between core sample communities and other geoscience disciplines continue to create barriers to implementation. Core samples involve parent-child relationships spanning 8 or more generations, an exponential increase in sample numbers between levels in the hierarchy, concepts related to depth/position in the sample, requirements for associating data derived from core scanning and lithologic description with data derived from subsample analysis, and publications based on tens of thousands of co-registered scan data points and thousands of analyses of subsamples. These characteristics require specialized resources for accurate and consistent assignment of IGSNs, and a community of practice to establish norms

Facile Synthesis of Carbon Nanosphere/NiCo2O4 Core-shell Sub-microspheres for High Performance Supercapacitor

PubMed Central

Li, Delong; Gong, Youning; Zhang, Yupeng; Luo, Chengzhi; Li, Weiping; Fu, Qiang; Pan, Chunxu

2015-01-01

This paper introduced a process to prepare the carbon nanosphere (CNS)/NiCo2O4 core-shell sub-microspheres. That is: 1) CNSs were firstly prepared via a simple hydrothermal method; 2) a layer of NiCo2O4 precursor was coated on the CNS surface; 3) finally the composite was annealed at 350 °C for 2 hours in the air, and the CNS/NiCo2O4 core-shell sub-microspheres were obtained. This core-shell sub-microsphere was prepared with a simple, economical and environmental-friendly hydrothermal method, and was suitable for large-scale production, which expects a promising electrode candidate for high performance energy storage applications. Electrochemical experiments revealed that the composite exhibited remarkable electrochemical performances with high capacitance and desirable cycle life at high rates, such as: 1) the maximum specific capacitance was up to 1420 F/g at 1 A/g; 2) about 98.5% of the capacitance retained after 3000 charge-discharge cycles; 3) the capacitance retention was about 72% as the current density increase from 1 A/g to 10 A/g. PMID:26245982

Evidence of orbital forcing in lake-level fluctuations in the Middle Eocene oil shale-bearing lacustrine successions in the Mudurnu-Göynük Basin, NW Anatolia (Turkey)

NASA Astrophysics Data System (ADS)

Ocakoğlu, F.; Açıkalın, S.; Yılmaz, İ. Ö.; Şafak, Ü.; Gökçeoğlu, C.

2012-08-01

Mudurnu-Göynük basin of the Sakarya Zone in NW Anatolia comprises ca. 1500 m thick Paleocene-Eocene terrestrial to shallow marine succession overlying the Late Cretaceous deeper marine progradational fore-arc sediments. Formed in a foreland setting in relation to southerly situated İzmir-Ankara suture zone, this terrestrial succession (regionally known as Kızılçay group) comprises a thin (<200 m) oil shale-bearing lacustrine section with very good cyclic patterns that potentially serves the quantification of stratigraphy and enlightening the origin of cyclicities of various hierarchy. Our detailed facies analysis on three correlative measured sections showed that mudstone, oil shale and thinner limestone alternations characterize the relatively deeper part of the Eocene lake with probable marine intervention, while thicker limestone, coal, marl and occasional oil shale alternations typify the southern relatively freshwater shoal areas. These facies are frequently organized as meter-scale symmetric to asymmetric transgressive-regressive cycles. Spectral analysis of the mudstone beds and the cycles within the lacustrine succession strongly indicates the occurrence of full bands of Milankovitch with the shortest precession cycle (19 ka) at ca. 2.30 m. Our observations further revealed quite rhythmic thin couplets with estimated durations of 365-730 yr that might represent abrupt climatic changes during deposition. On the other hand, longer duration (ca. 1 Ma) of shoaling and deepening trends in the studied sections were attributed basically to varying subsidence due to tectonic loading in the southerly suture zone. Lastly, regarding the distribution of depositional environments we propose that the oil shale exploration activities should be carried out within a 20 km wide E-W running belt while the southern limits of this belt is more prolific for coal resources.

Computational Science at the Argonne Leadership Computing Facility

NASA Astrophysics Data System (ADS)

Romero, Nichols

2014-03-01

The goal of the Argonne Leadership Computing Facility (ALCF) is to extend the frontiers of science by solving problems that require innovative approaches and the largest-scale computing systems. ALCF's most powerful computer - Mira, an IBM Blue Gene/Q system - has nearly one million cores. How does one program such systems? What software tools are available? Which scientific and engineering applications are able to utilize such levels of parallelism? This talk will address these questions and describe a sampling of projects that are using ALCF systems in their research, including ones in nanoscience, materials science, and chemistry. Finally, the ways to gain access to ALCF resources will be presented. This research used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under contract DE-AC02-06CH11357.

A theoretical and experimental benchmark study of core-excited states in nitrogen

NASA Astrophysics Data System (ADS)

Myhre, Rolf H.; Wolf, Thomas J. A.; Cheng, Lan; Nandi, Saikat; Coriani, Sonia; Gühr, Markus; Koch, Henrik

2018-02-01

The high resolution near edge X-ray absorption fine structure spectrum of nitrogen displays the vibrational structure of the core-excited states. This makes nitrogen well suited for assessing the accuracy of different electronic structure methods for core excitations. We report high resolution experimental measurements performed at the SOLEIL synchrotron facility. These are compared with theoretical spectra calculated using coupled cluster theory and algebraic diagrammatic construction theory. The coupled cluster singles and doubles with perturbative triples model known as CC3 is shown to accurately reproduce the experimental excitation energies as well as the spacing of the vibrational transitions. The computational results are also shown to be systematically improved within the coupled cluster hierarchy, with the coupled cluster singles, doubles, triples, and quadruples method faithfully reproducing the experimental vibrational structure.

First experimental demonstration of magnetic-field assisted fast heating of a dense plasma core

NASA Astrophysics Data System (ADS)

Fujioka, Shinsuke; Sakata, Shohei; Lee, Seung Ho; Matsuo, Kazuki; Sawada, Hiroshi; Iwasa, Yuki; Law, King Fai Farley; Morita, Hitoki; Kojima, Sadaoki; Abe, Yuki; Yao, Akira; Hata, Masayasu; Johzaki, Tomoyuki; Sunahara, Atsushi; Ozaki, Tetsuo; Sakagami, Hitoshi; Morace, Alessio; Arikawa, Yasunobu; Yogo, Akifumi; Nishimura, Hiroaki; Nakai, Mitsuo; Shiraga, Hiroyuki; Sentoku, Yasuhiko; Nagatomo, Hideo; Azechi, Hiroshi; Firex Project Team

2016-10-01

Fast heating of a dense plasma core by an energetic electron beam is being studied on GEKKO-LFEX laser facility. Here, we introduce a laser-driven kilo-tesla external magnetic field to guide the diverging electron beam to the dense plasma core. This involve placing a spherical target in the magnetic field, compressing it with the GEKKO-XII laser beams and then using the LFEX laser beams injected into the dense plasma to generate the electron beam which do the fast heating. Cu-Ka emission is used to visualize transport or heating processes of a dense plasma. X-ray spectrum from a highly ionized Cu ions indicates several keV of the temperature increment induced by the LFEX.

Highly Stretchable Core-Sheath Fibers via Wet-Spinning for Wearable Strain Sensors.

PubMed

Tang, Zhenhua; Jia, Shuhai; Wang, Fei; Bian, Changsheng; Chen, Yuyu; Wang, Yonglin; Li, Bo

2018-02-21

Lightweight, stretchable, and wearable strain sensors have recently been widely studied for the development of health monitoring systems, human-machine interfaces, and wearable devices. Herein, highly stretchable polymer elastomer-wrapped carbon nanocomposite piezoresistive core-sheath fibers are successfully prepared using a facile and scalable one-step coaxial wet-spinning assembly approach. The carbon nanotube-polymeric composite core of the stretchable fiber is surrounded by an insulating sheath, similar to conventional cables, and shows excellent electrical conductivity with a low percolation threshold (0.74 vol %). The core-sheath elastic fibers are used as wearable strain sensors, exhibiting ultra-high stretchability (above 300%), excellent stability (>10 000 cycles), fast response, low hysteresis, and good washability. Furthermore, the piezoresistive core-sheath fiber possesses bending-insensitiveness and negligible torsion-sensitive properties, and the strain sensing performance of piezoresistive fibers maintains a high degree of stability under harsh conditions. On the basis of this high level of performance, the fiber-shaped strain sensor can accurately detect both subtle and large-scale human movements by embedding it in gloves and garments or by directly attaching it to the skin. The current results indicate that the proposed stretchable strain sensor has many potential applications in health monitoring, human-machine interfaces, soft robotics, and wearable electronics.

Reconstruction of paleostorm history using geochemical proxies in sediment cores from Eastern Lake, Florida

NASA Astrophysics Data System (ADS)

Das, O.; Wang, Y.; Donoghue, J. F.; Coor, J. L.; Kish, S.; Elsner, J.; Hu, X. B.; Niedoroda, A. W.; Ye, M.; Xu, Y.

2009-12-01

Analysis of geochemical proxies of coastal lake sediments provides a useful tool for reconstructing paleostorm history. Such paleostorm records can help constrain models that are used to predict future storm events. In this study, we collected two sediment cores (60 and 103 cm long, respectively) from the center of Eastern Lake located on the Gulf coast of NW Florida. These cores, which are mainly composed of organic-rich mud and organic-poor sand, were sub-sampled at 2-3mm intervals for analyses of their organic carbon and nitrogen concentrations as well as δ13C and δ15N isotopic signatures. Selected samples were submitted for radiocarbon dating in order to establish a chronological framework for the interpretation of the geochemical data. There are significant variations in δ13C, δ15N, C%, N% and C/N with depth. The δ13C and δ15N values vary from -21.8‰ to -26.7‰ and 2.6‰ to 5‰, respectively. The stable isotopic signatures of carbon and nitrogen indicate that the sources of organic matter in sediments include terrestrial C3 type vegetation, marine input from Gulf of Mexico and biological productivity within the lake, such as phytoplankton and zooplankton growing in the lacustrine environment. The δ13C and δ15N values exhibit significant negative excursions by 2‰ in a 30 cm thick sand layer, bounded by a rapid return to the base value. A positive shift in the δ15N record observed in the upper part of the cores likely reflects increased anthropogenic input of N such as sewage or septic tank effluents associated with recent development of areas around the lake for human habitation. Similarly, organic C% and N% range from 5.8 to 0.4 and 0.4 to 0.1, respectively. A prominent negative shift by 2σ relative to the baseline in C% and N% has been observed at approx. 55 to 58 cm depth, consisting of an organic-poor sand layer. This shift in C% and N% can be correlated with the negative shift in the δ13C and δ15N values, indicating a major storm event

Late Cenozoic geology and lacustrine history of Searles Valley, Inyo and San Bernardino Counties, California

NASA Astrophysics Data System (ADS)

Nathenson, M.; Smith, G. I.; Robinson, J. E.; Stauffer, P. H.; Zigler, J. L.

2010-12-01

George Smith’s career-long study of the surface geology of the Searles Valley was recently published by the USGS (Smith, 2009, online and printed). The co-authors of this abstract are the team responsible for completing the publication from the original materials. Searles Valley is an arid, closed basin lying 70 km east of the south end of the Sierra Nevada, California. During those parts of late Pliocene and Pleistocene time when precipitation and runoff from the east side of the Sierra Nevada into the Owens River were much greater than at present, a chain of as many as five large lakes was created, of which Searles Lake was third. The stratigraphic record left in Searles Valley when that lake expanded, contracted, or desiccated is fully revealed by cores taken from beneath the surface of Searles (dry) Lake and partly recorded by sediments cropping out around the edge of the valley. Although this outcrop record is discontinuous, it provides direct evidence of the lake’s water depths during each expansion, which the subsurface record does not. Maximum-depth lakes rose to the 2,280-ft (695 m) contour, the level of the spillway that led overflowing waters to Panamint Valley; that spillway is about 660 ft (200 m) above the present dry-lake surface. Most of this study concerns sediments of the newly described Searles Lake Formation, whose deposition spanned the period between about 150 ka and 2 ka. The outcrop record is documented in six geologic maps (scales: 1:50,000 and 1:10,000). The Searles Lake Formation is divided into seven main units. The depositional intervals of the units that make up the Searles Lake Formation are determined primarily by correlation with subsurface deposits that are dated by radiocarbon ages on organic carbon and U-series dates on salts. Shorelines, the most obvious geologic expressions of former lakes, are abundant around Searles Valley. Erosional shorelines have cut as much as 100 m into brecciated bedrock; depositional shorelines

Core formation and core composition from coupled geochemical and geophysical constraints

DOE PAGES

Badro, James; Brodholt, John P.; Piet, Helene; ...

2015-09-21

The formation of Earth’s core left behind geophysical and geochemical signatures in both the core and mantle that remain to this day. Seismology requires that the core be lighter than pure iron and therefore must contain light elements, and the geochemistry of mantle-derived rocks reveals extensive siderophile element depletion and fractionation. Both features are inherited from metal–silicate differentiation in primitive Earth and depend upon the nature of physiochemical conditions that prevailed during core formation. To date, core formation models have only attempted to address the evolution of core and mantle compositional signatures separately, rather than seeking a joint solution. Heremore » we combine experimental petrology, geochemistry, mineral physics and seismology to constrain a range of core formation conditions that satisfy both constraints. We find that core formation occurred in a hot (liquidus) yet moderately deep magma ocean not exceeding 1,800 km depth, under redox conditions more oxidized than present-day Earth. This new scenario, at odds with the current belief that core formation occurred under reducing conditions, proposes that Earth’s magma ocean started oxidized and has become reduced through time, by oxygen incorporation into the core. As a result, this core formation model produces a core that contains 2.7–5% oxygen along with 2–3.6% silicon, with densities and velocities in accord with radial seismic models, and leaves behind a silicate mantle that matches the observed mantle abundances of nickel, cobalt, chromium, and vanadium.« less

Core formation and core composition from coupled geochemical and geophysical constraints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Badro, James; Brodholt, John P.; Piet, Helene

The formation of Earth’s core left behind geophysical and geochemical signatures in both the core and mantle that remain to this day. Seismology requires that the core be lighter than pure iron and therefore must contain light elements, and the geochemistry of mantle-derived rocks reveals extensive siderophile element depletion and fractionation. Both features are inherited from metal–silicate differentiation in primitive Earth and depend upon the nature of physiochemical conditions that prevailed during core formation. To date, core formation models have only attempted to address the evolution of core and mantle compositional signatures separately, rather than seeking a joint solution. Heremore » we combine experimental petrology, geochemistry, mineral physics and seismology to constrain a range of core formation conditions that satisfy both constraints. We find that core formation occurred in a hot (liquidus) yet moderately deep magma ocean not exceeding 1,800 km depth, under redox conditions more oxidized than present-day Earth. This new scenario, at odds with the current belief that core formation occurred under reducing conditions, proposes that Earth’s magma ocean started oxidized and has become reduced through time, by oxygen incorporation into the core. As a result, this core formation model produces a core that contains 2.7–5% oxygen along with 2–3.6% silicon, with densities and velocities in accord with radial seismic models, and leaves behind a silicate mantle that matches the observed mantle abundances of nickel, cobalt, chromium, and vanadium.« less

Mass Spectrometry Data Collection in Parallel at Multiple Core Facilities Operating TripleTOF 5600 and Orbitrap Elite/Velos Pro/Q Exactive Mass Spectrometers

PubMed Central

Jones, K.; Kim, K.; Patel, B.; Kelsen, S.; Braverman, A.; Swinton, D.; Gafken, P.; Jones, L.; Lane, W.; Neveu, J.; Leung, H.; Shaffer, S.; Leszyk, J.; Stanley, B.; Fox, T.; Stanley, A.; Yeung, Anthony

2013-01-01

Proteomic research can benefit from simultaneous access to multiple cutting-edge mass spectrometers. 18 core facilities responded to our investigators seeking service through the ABRF Discussion Forum. Five of the facilities selected completed four plasma proteomics experiments as routine fee-for-service. Each biological experiment entailed an iTRAQ 4-plex proteome comparison of immunodepleted plasma provided as 30 labeled-peptide fractions. Identical samples were analyzed by two AB SCIEX TripleTOF 5600 and three Thermo Orbitrap (Elite/Velos Pro/Q Exactive) instruments. 480 LC-MS/MS runs delivered >250 GB of data over two months. We compare herein routine service analyses of three peptide fractions of different peptide abundance. Data files from each instrument were studied to develop optimal analysis parameters to compare with default parameters in Mascot Distiller 2.4, ProteinPilot 4.5 beta, AB Sciex MS Data Converter 1.3 beta, and Proteome Discover 1.3. Peak-picking for TripleTOFs was best by ProteinPilot 4.5 beta while Mascot Distiller and Proteome Discoverer were comparable for the Orbitraps. We compared protein identification and quantitation in SwissProt 2012_07 database by Mascot Server 2.4.01 versus ProteinPilot. By all search methods, more proteins, up to two fold, were identified using the Q Exactive than others. Q Exactive excelled also at the number of unique significant peptide ion sequences. However, software-dependent impact on subsequent interpretation, due to peptide modifications, can be critical. These findings may have special implications for iTRAQ plasma proteomics. For the low abundance peptide ions, the slope of the dynamic range drop-off in the plasma proteome is uniquely sharp compared with cell lysates. Our study provides data for testable improvements in the operation of these mass spectrometers. More importantly, we have demonstrated a new affordable expedient workflow for investigators to perform proteomic experiments through the ABRF

Operational Philosophy for the Advanced Test Reactor National Scientific User Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

J. Benson; J. Cole; J. Jackson

2013-02-01

In 2007, the Department of Energy (DOE) designated the Advanced Test Reactor (ATR) as a National Scientific User Facility (NSUF). At its core, the ATR NSUF Program combines access to a portion of the available ATR radiation capability, the associated required examination and analysis facilities at the Idaho National Laboratory (INL), and INL staff expertise with novel ideas provided by external contributors (universities, laboratories, and industry). These collaborations define the cutting edge of nuclear technology research in high-temperature and radiation environments, contribute to improved industry performance of current and future light-water reactors (LWRs), and stimulate cooperative research between user groupsmore » conducting basic and applied research. To make possible the broadest access to key national capability, the ATR NSUF formed a partnership program that also makes available access to critical facilities outside of the INL. Finally, the ATR NSUF has established a sample library that allows access to pre-irradiated samples as needed by national research teams.« less

Galaxy and Mass Assembly (GAMA): survey diagnostics and core data release

NASA Astrophysics Data System (ADS)

Driver, S. P.; Hill, D. T.; Kelvin, L. S.; Robotham, A. S. G.; Liske, J.; Norberg, P.; Baldry, I. K.; Bamford, S. P.; Hopkins, A. M.; Loveday, J.; Peacock, J. A.; Andrae, E.; Bland-Hawthorn, J.; Brough, S.; Brown, M. J. I.; Cameron, E.; Ching, J. H. Y.; Colless, M.; Conselice, C. J.; Croom, S. M.; Cross, N. J. G.; de Propris, R.; Dye, S.; Drinkwater, M. J.; Ellis, S.; Graham, Alister W.; Grootes, M. W.; Gunawardhana, M.; Jones, D. H.; van Kampen, E.; Maraston, C.; Nichol, R. C.; Parkinson, H. R.; Phillipps, S.; Pimbblet, K.; Popescu, C. C.; Prescott, M.; Roseboom, I. G.; Sadler, E. M.; Sansom, A. E.; Sharp, R. G.; Smith, D. J. B.; Taylor, E.; Thomas, D.; Tuffs, R. J.; Wijesinghe, D.; Dunne, L.; Frenk, C. S.; Jarvis, M. J.; Madore, B. F.; Meyer, M. J.; Seibert, M.; Staveley-Smith, L.; Sutherland, W. J.; Warren, S. J.

2011-05-01

The Galaxy and Mass Assembly (GAMA) survey has been operating since 2008 February on the 3.9-m Anglo-Australian Telescope using the AAOmega fibre-fed spectrograph facility to acquire spectra with a resolution of R≈ 1300 for 120 862 Sloan Digital Sky Survey selected galaxies. The target catalogue constitutes three contiguous equatorial regions centred at 9h (G09), 12h (G12) and 14.5h (G15) each of 12 × 4 deg2 to limiting fluxes of rpet < 19.4, rpet < 19.8 and rpet < 19.4 mag, respectively (and additional limits at other wavelengths). Spectra and reliable redshifts have been acquired for over 98 per cent of the galaxies within these limits. Here we present the survey footprint, progression, data reduction, redshifting, re-redshifting, an assessment of data quality after 3 yr, additional image analysis products (including ugrizYJHK photometry, Sérsic profiles and photometric redshifts), observing mask and construction of our core survey catalogue (GamaCore). From this we create three science-ready catalogues: GamaCoreDR1 for public release, which includes data acquired during year 1 of operations within specified magnitude limits (2008 February to April); GamaCoreMainSurvey containing all data above our survey limits for use by the GAMA Team and collaborators; and GamaCoreAtlasSV containing year 1, 2 and 3 data matched to Herschel-ATLAS science demonstration data. These catalogues along with the associated spectra, stamps and profiles can be accessed via the GAMA website:

Testing of an Integrated Reactor Core Simulator and Power Conversion System with Simulated Reactivity Feedback

NASA Technical Reports Server (NTRS)

Bragg-Sitton, Shannon M.; Hervol, David S.; Godfroy, Thomas J.

2009-01-01

A Direct Drive Gas-Cooled (DDG) reactor core simulator has been coupled to a Brayton Power Conversion Unit (BPCU) for integrated system testing at NASA Glenn Research Center (GRC) in Cleveland, OH. This is a closed-cycle system that incorporates an electrically heated reactor core module, turbo alternator, recuperator, and gas cooler. Nuclear fuel elements in the gas-cooled reactor design are replaced with electric resistance heaters to simulate the heat from nuclear fuel in the corresponding fast spectrum nuclear reactor. The thermodynamic transient behavior of the integrated system was the focus of this test series. In order to better mimic the integrated response of the nuclear-fueled system, a simulated reactivity feedback control loop was implemented. Core power was controlled by a point kinetics model in which the reactivity feedback was based on core temperature measurements; the neutron generation time and the temperature feedback coefficient are provided as model inputs. These dynamic system response tests demonstrate the overall capability of a non-nuclear test facility in assessing system integration issues and characterizing integrated system response times and response characteristics.

Testing of an Integrated Reactor Core Simulator and Power Conversion System with Simulated Reactivity Feedback

NASA Technical Reports Server (NTRS)

Bragg-Sitton, Shannon M.; Hervol, David S.; Godfroy, Thomas J.

2010-01-01

A Direct Drive Gas-Cooled (DDG) reactor core simulator has been coupled to a Brayton Power Conversion Unit (BPCU) for integrated system testing at NASA Glenn Research Center (GRC) in Cleveland, Ohio. This is a closed-cycle system that incorporates an electrically heated reactor core module, turboalternator, recuperator, and gas cooler. Nuclear fuel elements in the gas-cooled reactor design are replaced with electric resistance heaters to simulate the heat from nuclear fuel in the corresponding fast spectrum nuclear reactor. The thermodynamic transient behavior of the integrated system was the focus of this test series. In order to better mimic the integrated response of the nuclear-fueled system, a simulated reactivity feedback control loop was implemented. Core power was controlled by a point kinetics model in which the reactivity feedback was based on core temperature measurements; the neutron generation time and the temperature feedback coefficient are provided as model inputs. These dynamic system response tests demonstrate the overall capability of a non-nuclear test facility in assessing system integration issues and characterizing integrated system response times and response characteristics.

Reconstruction of TiO2/MnO2-C nanotube/nanoflake core/shell arrays as high-performance supercapacitor electrodes

NASA Astrophysics Data System (ADS)

Xiong, Qinqin; Zheng, Cun; Chi, Hongzhong; Zhang, Jun; Ji, Zhenguo

2017-02-01

Construction of electrodes with fast reaction kinetics is of great importance for achieving advanced supercapacitors. Herein we report a facile combined synthetic strategy with atomic layer deposition (ALD) and electrodeposition to rationally fabricate nanotube/nanoflake core/shell arrays. ALD-TiO2 nanotubes are used as the skeleton core for assembly of electrodeposited MnO2-C nanoflake shells forming a core/shell structure. Highly porous architecture and good electrical conductivity are combined in this unique core/shell structure, resulting in fast ion/electron transfer. In tests of electrochemical performance, the TiO2/MnO2-C core/shell arrays are characterized as cathode for asymmetric supecapacitors and exhibit high specific capacitance (880 F g-1 at 2.5 A g-1), excellent rate properties (735 F g-1 at 30 A g-1) and good long-term cycling stability (94.3% capacitance retention after 20 000 cycles). The proposed electrode construction strategy is favorable for fabrication of other advanced supercapacitor electrodes.

Reconstruction of TiO2/MnO2-C nanotube/nanoflake core/shell arrays as high-performance supercapacitor electrodes.

PubMed

Xiong, Qinqin; Zheng, Cun; Chi, Hongzhong; Zhang, Jun; Ji, Zhenguo

2017-02-03

Construction of electrodes with fast reaction kinetics is of great importance for achieving advanced supercapacitors. Herein we report a facile combined synthetic strategy with atomic layer deposition (ALD) and electrodeposition to rationally fabricate nanotube/nanoflake core/shell arrays. ALD-TiO 2 nanotubes are used as the skeleton core for assembly of electrodeposited MnO 2 -C nanoflake shells forming a core/shell structure. Highly porous architecture and good electrical conductivity are combined in this unique core/shell structure, resulting in fast ion/electron transfer. In tests of electrochemical performance, the TiO 2 /MnO 2 -C core/shell arrays are characterized as cathode for asymmetric supecapacitors and exhibit high specific capacitance (880 F g -1 at 2.5 A g -1 ), excellent rate properties (735 F g -1 at 30 A g -1 ) and good long-term cycling stability (94.3% capacitance retention after 20 000 cycles). The proposed electrode construction strategy is favorable for fabrication of other advanced supercapacitor electrodes.

Formulation and preparation of Hanford Waste Treatment Plant direct feed low activity waste Effluent Management Facility core simulant

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCabe, Daniel J.; Nash, Charles A.; Adamson, Duane J.

The Hanford Waste Treatment and Immobilization Plant (WTP) Low Activity Waste (LAW) vitrification facility will generate an aqueous condensate recycle stream (LAW Melter Off-Gas Condensate, LMOGC) from the off-gas system. The baseline plan for disposition of this stream during full WTP operations is to send it to the WTP Pretreatment Facility, where it will be blended with LAW, concentrated by evaporation and recycled to the LAW vitrification facility. However, during the Direct Feed LAW (DFLAW) scenario, planned disposition of this stream is to evaporate it in a new evaporator in the Effluent Management Facility (EMF) and then return it tomore » the LAW melter. It is important to understand the composition of the effluents from the melter and new evaporator so that the disposition of these streams can be accurately planned and accommodated. Furthermore, alternate disposition of the LMOGC stream would eliminate recycling of problematic components, and would enable less integrated operation of the LAW melter and the Pretreatment Facilities. Alternate disposition would also eliminate this stream from recycling within WTP when it begins operations and would decrease the LAW vitrification mission duration and quantity of glass waste, amongst the other problems such a recycle stream present. This LAW Melter Off-Gas Condensate stream will contain components that are volatile at melter temperatures and are problematic for the glass waste form, such as halides and sulfate. Because this stream will recycle within WTP, these components accumulate in the Melter Condensate stream, exacerbating their impact on the number of LAW glass containers that must be produced. Diverting the stream reduces the halides and sulfate in the recycled Condensate and is a key outcome of this work. This overall program examines the potential treatment and immobilization of this stream to enable alternative disposal. The objective of this task was to formulate and prepare a simulant of the LAW

Paleolimnology of lacustrine rocks in Stewart Valley, Nevada: Evidence for Middle Miocene climatic cooling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Starrat, S.W.

1993-04-01

Three diatom floras from Middle Miocene (Barstovian and Clarendonian) lacustrine rocks in Stewart Valley, Nevada have been distinguished. The change in floral composition between the two youngest floras may be indicative of climatic cooling over a period of about 3 m.y. (15--12 Ma). Age control is provided by radiometric (K-Ar) and vertebrate fossil data. The oldest flora is dominated by members of the genus Fragilaria'. Although most common in modern-day marshy areas, the laminated nature of the Stewart Valley strata in which this flora is found suggest that large numbers of these diatoms were washed into deeper waters, where theymore » continued to thrive as a significant part of the planktonic biomass. Stratigraphically equivalent rocks elsewhere in Stewart Valley contain abundant clusters of unopened prasinophyte algae. These unopened algal structures are thought to indicate extreme environmental stress. Environmental stress would also explain the presence of several beds of well-preserved fish fossils in stratigraphically adjacent beds. The other tow floras are preserved in a 45-m-thick section of diatomaceous shale, located about 95 m above the flora discussed above. The flora in the lower part of this section is dominated by the genus Aulacoseira (primarily A. granulata). Modern-day members of this genus are common in areas with abundant summer precipitation and mild winters. The flora in the upper part of the section is dominated by Actinocyclus cedarensis Bradbury and Krebs. If A. cedarensis can be considered an ecological analog of the late Pleistocene (glacial) representatives of the genus Stephanodiscus, then its dominant position in the flora may be indicative of a cooling event. This climate trend is also evident in paleobotanical (leaf and pollen) data from Stewart Valley, as well as many other localities across the Great Basin.« less

Inner core structure behind the PKP core phase triplication

NASA Astrophysics Data System (ADS)

Blom, Nienke A.; Deuss, Arwen; Paulssen, Hanneke; Waszek, Lauren

2015-06-01

The structure of the Earth's inner core is not well known between depths of ˜100-200 km beneath the inner core boundary. This is a result of the PKP core phase triplication and the existence of strong precursors to PKP phases, which hinder the measurement of inner core compressional PKIKP waves at epicentral distances between roughly 143 and 148°. Consequently, interpretation of the detailed structure of deeper regions also remains difficult. To overcome these issues we stack seismograms in slowness and time, separating the PKP and PKIKP phases which arrive simultaneously but with different slowness. We apply this method to study the inner core's Western hemisphere beneath South and Central America using paths travelling in the quasi-polar direction between 140 and 150° epicentral distance, which enables us to measure PKiKP-PKIKP differential traveltimes up to greater epicentral distance than has previously been done. The resulting PKiKP-PKIKP differential traveltime residuals increase with epicentral distance, which indicates a marked increase in seismic velocity for polar paths at depths greater than 100 km compared to reference model AK135. Assuming a homogeneous outer core, these findings can be explained by either (i) inner core heterogeneity due to an increase in isotropic velocity or (ii) increase in anisotropy over the studied depth range. Although this study only samples a small region of the inner core and the current data cannot distinguish between the two alternatives, we prefer the latter interpretation in the light of previous work.

Lessons Learned from the 200 West Pump and Treatment Facility Construction Project at the US DOE Hanford Site - A Leadership for Energy and Environmental Design (LEED) Gold-Certified Facility - 13113

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorr, Kent A.; Freeman-Pollard, Jhivaun R.; Ostrom, Michael J.

CH2M Hill Plateau Remediation Company (CHPRC) designed, constructed, commissioned, and began operation of the largest groundwater pump and treatment facility in the U.S. Department of Energy's (DOE) nationwide complex. This one-of-a-kind groundwater pump and treatment facility, located at the Hanford Nuclear Reservation Site (Hanford Site) in Washington State, was built to an accelerated schedule with American Recovery and Reinvestment Act (ARRA) funds. There were many contractual, technical, configuration management, quality, safety, and Leadership in Energy and Environmental Design (LEED) challenges associated with the design, procurement, construction, and commissioning of this $95 million, 52,000 ft groundwater pump and treatment facility tomore » meet DOE's mission objective of treating contaminated groundwater at the Hanford Site with a new facility by June 28, 2012. The project team's successful integration of the project's core values and green energy technology throughout design, procurement, construction, and start-up of this complex, first-of-its-kind Bio Process facility resulted in successful achievement of DOE's mission objective, as well as attainment of LEED GOLD certification (Figure 1), which makes this Bio Process facility the first non-administrative building in the DOE Office of Environmental Management complex to earn such an award. (authors)« less

Controllable synthesis of ZnxCd1-xS@ZnO core-shell nanorods with enhanced photocatalytic activity.

PubMed

Xie, Shilei; Lu, Xihong; Zhai, Teng; Gan, Jiayong; Li, Wei; Xu, Ming; Yu, Minghao; Zhang, Yuan-Ming; Tong, Yexiang

2012-07-17

We report the synthesis of Zn(x)Cd(1-x)S@ZnO nanorod arrays via a facile two-step process and the implementation of these core-shell nanorods as an environmental friendly and recyclable photocatalyst for methyl orange degradation. The band gap of Zn(x)Cd(1-x)S@ZnO core-shell nanorods can be readily tunable by adjusting the ratio of Zn/Cd during the synthesis. These Zn(x)Cd(1-x)S@ZnO core-shell nanorods exhibit a high photocatalytic activity and good stability in the degradation of the methyl orange. Moreover, these films grown on FTO substrates make the collection and recycle of the photocatalyst easier. These findings may open new opportunities for the design of effective, stable, and easy-recyclable photocatalytic materials.

NASA Reactor Facility Hazards Summary. Volume 1

NASA Technical Reports Server (NTRS)

1959-01-01

The Lewis Research Center of the National Aeronautics and Space Administration proposes to build a nuclear research reactor which will be located in the Plum Brook Ordnance Works near Sandusky, Ohio. The purpose of this report is to inform the Advisory Committee on Reactor Safeguards of the U. S. Atomic Energy Commission in regard to the design Lq of the reactor facility, the characteristics of the site, and the hazards of operation at this location. The purpose of this research reactor is to make pumped loop studies of aircraft reactor fuel elements and other reactor components, radiation effects studies on aircraft reactor materials and equipment, shielding studies, and nuclear and solid state physics experiments. The reactor is light water cooled and moderated of the MTR-type with a primary beryllium reflector and a secondary water reflector. The core initially will be a 3 by 9 array of MTR-type fuel elements and is designed for operation up to a power of 60 megawatts. The reactor facility is described in general terms. This is followed by a discussion of the nuclear characteristics and performance of the reactor. Then details of the reactor control system are discussed. A summary of the site characteristics is then presented followed by a discussion of the larger type of experiments which may eventually be operated in this facility. The considerations for normal operation are concluded with a proposed method of handling fuel elements and radioactive wastes. The potential hazards involved with failures or malfunctions of this facility are considered in some detail. These are examined first from the standpoint of preventing them or minimizing their effects and second from the standpoint of what effect they might have on the reactor facility staff and the surrounding population. The most essential feature of the design for location at the proposed site is containment of the maximum credible accident.

Core Research Center

USGS Publications Warehouse

Hicks, Joshua; Adrian, Betty

2009-01-01

The Core Research Center (CRC) of the U.S. Geological Survey (USGS), located at the Denver Federal Center in Lakewood, Colo., currently houses rock core from more than 8,500 boreholes representing about 1.7 million feet of rock core from 35 States and cuttings from 54,000 boreholes representing 238 million feet of drilling in 28 States. Although most of the boreholes are located in the Rocky Mountain region, the geologic and geographic diversity of samples have helped the CRC become one of the largest and most heavily used public core repositories in the United States. Many of the boreholes represented in the collection were drilled for energy and mineral exploration, and many of the cores and cuttings were donated to the CRC by private companies in these industries. Some cores and cuttings were collected by the USGS along with other government agencies. Approximately one-half of the cores are slabbed and photographed. More than 18,000 thin sections and a large volume of analytical data from the cores and cuttings are also accessible. A growing collection of digital images of the cores are also becoming available on the CRC Web site Internet http://geology.cr.usgs.gov/crc/.

Re-Os geochronology and Os isotope fingerprinting of petroleum sourced from a Type I lacustrine kerogen: Insights from the natural Green River petroleum system in the Uinta Basin and hydrous pyrolysis experiments

NASA Astrophysics Data System (ADS)

Cumming, Vivien M.; Selby, David; Lillis, Paul G.; Lewan, Michael D.

2014-08-01

Rhenium-osmium (Re-Os) geochronology of marine petroleum systems has allowed the determination of the depositional age of source rocks as well as the timing of petroleum generation. In addition, Os isotopes have been applied as a fingerprinting tool to correlate oil to its source unit. To date, only classic marine petroleum systems have been studied. Here we present Re-Os geochronology and Os isotope fingerprinting of different petroleum phases (oils, tar sands and gilsonite) derived from the lacustrine Green River petroleum system in the Uinta Basin, USA. In addition we use an experimental approach, hydrous pyrolysis experiments, to compare to the Re-Os data of naturally generated petroleum in order to further understand the mechanisms of Re and Os transfer to petroleum. The Re-Os geochronology of petroleum from the lacustrine Green River petroleum system (19 ± 14 Ma - all petroleum phases) broadly agrees with previous petroleum generation basin models (∼25 Ma) suggesting that Re-Os geochronology of variable petroleum phases derived from lacustrine Type I kerogen has similar systematics to Type II kerogen (e.g., Selby and Creaser, 2005a,b; Finlay et al., 2010). However, the large uncertainties (over 100% in some cases) produced for the petroleum Re-Os geochronology are a result of multiple generation events occurring through a ∼3000-m thick source unit that creates a mixture of initial Os isotope compositions in the produced petroleum phases. The 187Os/188Os values for the petroleum and source rocks at the time of oil generation vary from 1.4 to 1.9, with the mode at ∼1.6. Oil-to-source correlation using Os isotopes is consistent with previous correlation studies in the Green River petroleum system, and illustrates the potential utility of Os isotopes to characterize the spatial variations within a petroleum system. Hydrous pyrolysis experiments on the Green River Formation source rocks show that Re and Os transfer are mimicking the natural system. This

Re-Os geochronology and Os isotope fingerprinting of petroleum sourced from a Type I lacustrine kerogen: insights from the natural Green River petroleum system in the Uinta Basin and hydrous pyrolysis experiments

USGS Publications Warehouse

Cumming, Vivien M.; Selby, David; Lillis, Paul G.; Lewan, Michael D.

2014-01-01

Rhenium–osmium (Re–Os) geochronology of marine petroleum systems has allowed the determination of the depositional age of source rocks as well as the timing of petroleum generation. In addition, Os isotopes have been applied as a fingerprinting tool to correlate oil to its source unit. To date, only classic marine petroleum systems have been studied. Here we present Re–Os geochronology and Os isotope fingerprinting of different petroleum phases (oils, tar sands and gilsonite) derived from the lacustrine Green River petroleum system in the Uinta Basin, USA. In addition we use an experimental approach, hydrous pyrolysis experiments, to compare to the Re–Os data of naturally generated petroleum in order to further understand the mechanisms of Re and Os transfer to petroleum. The Re–Os geochronology of petroleum from the lacustrine Green River petroleum system (19 ± 14 Ma – all petroleum phases) broadly agrees with previous petroleum generation basin models (∼25 Ma) suggesting that Re–Os geochronology of variable petroleum phases derived from lacustrine Type I kerogen has similar systematics to Type II kerogen (e.g., Selby and Creaser, 2005a, Selby and Creaser, 2005b and Finlay et al., 2010). However, the large uncertainties (over 100% in some cases) produced for the petroleum Re–Os geochronology are a result of multiple generation events occurring through a ∼3000-m thick source unit that creates a mixture of initial Os isotope compositions in the produced petroleum phases. The 187Os/188Os values for the petroleum and source rocks at the time of oil generation vary from 1.4 to 1.9, with the mode at ∼1.6. Oil-to-source correlation using Os isotopes is consistent with previous correlation studies in the Green River petroleum system, and illustrates the potential utility of Os isotopes to characterize the spatial variations within a petroleum system. Hydrous pyrolysis experiments on the Green River Formation source rocks show that Re and Os transfer

The 87Sr/86Sr ratios of lacustrine carbonates and lake-level history of the Bonneville paleolake system

USGS Publications Warehouse

Hart, W.S.; Quade, Jay; Madsen, D.B.; Kaufman, D.S.; Oviatt, Charles G.

2004-01-01

Lakes in the Bonneville basin have fluctuated dramatically in response to changes in rainfall, temperature, and drainage diversion during the Quaternary. We analyzed tufas and shells from shorelines of known ages in order to develop a relation between 87Sr/86Sr ratio of carbonates and lake level, which then can be used as a basis for constraining lake level from similar analyses on carbonates in cores. Carbonates from the late Quaternary shorelines yield the following average 87Sr/86Sr ratios: 0.71173 for the Stansbury shoreline (22-20 14C ka; 1350 m), 0.71153 for the Bonneville shoreline (15.5-14.5 14C ka; 1550 m), 0.71175 for the Provo shoreline (14.4-14.0 14C ka; 1450 m), 0.71244 for the Gilbert shoreline (???10.3-10.9 14C ka; 1300 m), and 0.71469 for the modern Great Salt Lake (1280 m). These analyses show that the 87Sr/86Sr ratio of lacustrine carbonates changes substantially at low- to mid-lake levels but is invariant at mid- to high-lake levels. Sr-isotope mixing models of Great Salt Lake and the Bonneville paleolake system were constructed to explain these variations in 87Sr/86Sr ratios with change in lake level. Our model of the Bonneville system produced a 87Sr/86Sr ratio of 0.71193, very close to the observed ratios from high-shoreline tufa and shell. The model verifies that the integration of the southern Sevier and Beaver rivers with the Bear and others rivers in the north is responsible for the lower 87Sr/86Sr ratios in Lake Bonneville compared to the modern Great Salt Lake. We also modeled the 87Sr/86Sr ratio of Lake Bonneville with the upper Bear River diverted into the Snake River basin and obtained an 87Sr/86Sr ratio of 0.71414. Coincidentally, this ratio is close to the observed ratio for Great Salt Lake of 0.71469. This means that 87Sr/86Sr ratios of >0.714 for carbonate can be produced by climatically induced low-lake conditions or by diversion of the upper Bear River out of the Bonneville basin. This model result also demonstrates that the

43 CFR 3593.1 - Core or test hole cores, samples, cuttings.

Code of Federal Regulations, 2014 CFR

2014-10-01

.... (d) When drilling on lands with potential for encountering high pressure oil, gas or geothermal... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Core or test hole cores, samples, cuttings...) EXPLORATION AND MINING OPERATIONS Bore Holes and Samples § 3593.1 Core or test hole cores, samples, cuttings...

43 CFR 3593.1 - Core or test hole cores, samples, cuttings.

Code of Federal Regulations, 2012 CFR

2012-10-01

.... (d) When drilling on lands with potential for encountering high pressure oil, gas or geothermal... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Core or test hole cores, samples, cuttings...) EXPLORATION AND MINING OPERATIONS Bore Holes and Samples § 3593.1 Core or test hole cores, samples, cuttings...

43 CFR 3593.1 - Core or test hole cores, samples, cuttings.

Code of Federal Regulations, 2013 CFR

2013-10-01

.... (d) When drilling on lands with potential for encountering high pressure oil, gas or geothermal... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Core or test hole cores, samples, cuttings...) EXPLORATION AND MINING OPERATIONS Bore Holes and Samples § 3593.1 Core or test hole cores, samples, cuttings...

43 CFR 3593.1 - Core or test hole cores, samples, cuttings.

Code of Federal Regulations, 2011 CFR

2011-10-01

.... (d) When drilling on lands with potential for encountering high pressure oil, gas or geothermal... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Core or test hole cores, samples, cuttings...) EXPLORATION AND MINING OPERATIONS Bore Holes and Samples § 3593.1 Core or test hole cores, samples, cuttings...

Synthesis of SiCN@TiO2 core-shell ceramic microspheres via PDCs method

NASA Astrophysics Data System (ADS)

Liu, Hongli; Wei, Ning; Li, Jing; Zhang, Haiyuan; Chu, Peng

2018-02-01

A facile and effective polymer-derived ceramics (PDCs) emulsification-crosslinking-pyrolysis method was developed to fabricate SiCN@TiO2 core-shell ceramic microspheres with polyvinylsilazane (PVSZ) and tetrabutyl titanate (TBT) as precursors. The TBT: PVSZ mass ratios, emulsifier concentrations and the pyrolysis temperature were examined as control parameters to tune the size and morphology of microspheres. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed the synthesized SiCN@TiO2 microspheres to be comprised of SiCN core coated with TiO2 crystals, with an average size of 0.88 μm when pyrolyzed at 1400 °C. The analysis of Fourier transform infrared spectroscopy (FT-IR), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) ensured that SiCN@TiO2 core-shell ceramic microspheres composed of rutile TiO2, β-SiC and Si3N4 crystalline phases, The thermal properties were characterized by thermogravimetric analysis (TGA). The obtained SiCN@TiO2 core-shell ceramic microspheres were the promising candidate of the infrared opacifier in silica aerogels and this technique can be extended to other preceramic polymers.

33. BENCH CORE STATION, GREY IRON FOUNDRY CORE ROOM WHERE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. BENCH CORE STATION, GREY IRON FOUNDRY CORE ROOM WHERE CORE MOLDS WERE HAND FILLED AND OFTEN PNEUMATICALLY COMPRESSED WITH A HAND-HELD RAMMER BEFORE THEY WERE BAKED. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

Polydopamine and MnO2 core-shell composites for high-performance supercapacitors

NASA Astrophysics Data System (ADS)

Hou, Ding; Tao, Haisheng; Zhu, Xuezhen; Li, Maoguo

2017-10-01

Polydopamine and MnO2 core-shell composites (PDA@MnO2) for high-performance supercapacitors had been successfully synthesized by a facile and fast method. The morphology, crystalline phase and chemical composition of PDA@MnO2 composites are characterized using SEM, TEM, XRD, EDS and XPS. The performance of PDA@MnO2 composites are further investigated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy in 1 M Na2SO4 electrolyte. The PDA@MnO2 core-shell nanostructure composites exhibit a high capacitance of 193 F g-1 at the current density of 1A g-1 and retained over 81.2% of its initial capacitance after 2500 cycles of charge-discharge at 2 A g-1. The results manifest that the PDA@MnO2 composites can be potentially applied in supercapacitors.

A theoretical and experimental benchmark study of core-excited states in nitrogen

DOE PAGES

Myhre, Rolf H.; Wolf, Thomas J. A.; Cheng, Lan; ...

2018-02-14

The high resolution near edge X-ray absorption fine structure spectrum of nitrogen displays the vibrational structure of the core-excited states. This makes nitrogen well suited for assessing the accuracy of different electronic structure methods for core excitations. We report high resolution experimental measurements performed at the SOLEIL synchrotron facility. These are compared with theoretical spectra calculated using coupled cluster theory and algebraic diagrammatic construction theory. The coupled cluster singles and doubles with perturbative triples model known as CC3 is shown to accurately reproduce the experimental excitation energies as well as the spacing of the vibrational transitions. In conclusion, the computationalmore » results are also shown to be systematically improved within the coupled cluster hierarchy, with the coupled cluster singles, doubles, triples, and quadruples method faithfully reproducing the experimental vibrational structure.« less

A theoretical and experimental benchmark study of core-excited states in nitrogen

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myhre, Rolf H.; Wolf, Thomas J. A.; Cheng, Lan

The high resolution near edge X-ray absorption fine structure spectrum of nitrogen displays the vibrational structure of the core-excited states. This makes nitrogen well suited for assessing the accuracy of different electronic structure methods for core excitations. We report high resolution experimental measurements performed at the SOLEIL synchrotron facility. These are compared with theoretical spectra calculated using coupled cluster theory and algebraic diagrammatic construction theory. The coupled cluster singles and doubles with perturbative triples model known as CC3 is shown to accurately reproduce the experimental excitation energies as well as the spacing of the vibrational transitions. In conclusion, the computationalmore » results are also shown to be systematically improved within the coupled cluster hierarchy, with the coupled cluster singles, doubles, triples, and quadruples method faithfully reproducing the experimental vibrational structure.« less

Core drilling apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gusman, M.T.; Konstantinov, L.P.; Malkin, B.D.

1974-04-16

Mounted on the exterior of a nonrotatable core barrel is an end of a resilient tape, the other end of which extends inward into the barrel and is connected to a device for pulling the tape inward into the barrel. The apparatus also is provided with an arrangement which forms a sleeve from the tape as this is being pulled into the core barrel. During the coring operation, the tape is being pulled inward into the barrel and a sleeve is formed from the tape with the aid of the arrangement to encase and protect the core from disturbance. Themore » coring apparatus is intended for core drilling in soft, unconsolidated, and fractured formations. (3 claims)« less

Orion Core Stage & Booster Offload, Move to HIF

NASA Image and Video Library

2014-03-04

CAPE CANAVERAL, Fla. – The core booster for the United Launch Alliance Delta IV heavy for NASA’s upcoming Exploration Flight Test-1, or EFT-1, mission with the Orion spacecraft, was transported to the Horizontal Integration Facility, or HIF, at Space Launch Complex 37 on Cape Canaveral Air Force Station in Florida. The core booster and starboard booster arrived by barge at the U.S. Army Outpost wharf at Port Canaveral. The port booster and the upper stage are planned to be shipped to Cape Canaveral in April. At the HIF, all three boosters will be processed and checked out before being moved to the nearby launch pad and hoisted into position. During the EFT-1 mission, Orion will travel farther into space than any human spacecraft has gone in more than 40 years. The data gathered during the flight will influence design decisions, validate existing computer models and innovative new approaches to space systems development, as well as reduce overall mission risks and costs for later Orion flights. Liftoff of Orion on EFT-1 is planned for fall 2014. Photo credit: NASA/Kim Shiflett

Downgrading Nuclear Facilities to Radiological Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jarry, Jeffrey F.; Farr, Jesse Oscar; Duran, Leroy

2015-08-01

Based on inventory reductions and the use of alternate storage facilities, the Sandia National Laboratories (SNL) downgraded 4 SNL Hazard Category 3 (HC-3) nuclear facilities to less-than-HC-3 radiological facilities. SNL’s Waste Management and Pollution Prevention Department (WMPPD) managed the HC-3 nuclear facilities and implemented the downgrade. This paper will examine the downgrade process,

Fan Noise Test Facility

NASA Image and Video Library

1969-01-21

The Fan Noise Test Facility built at the Lewis Research Center to obtain far-field noise data for the National Aeronautics and Space Administration (NASA) and General Electric Quiet Engine Program. The engine incorporated existing noise reduction methods into an engine of similar power to those that propelled the Boeing 707 or McDonnell-Douglas DC-8 airliner. The new the low-bypass ratio turbofan engines of the 1960s were inherently quieter than their turbojet counterparts, researchers had a better grasp of the noise generation problem, and new acoustic technologies had emerged. Lewis contracted General Electric in 1969 to build and aerodynamically test three experimental engines with 72-inch diameter fans. The engines were then brought to Lewis and tested with an acoustically treated nacelle. This Fan Noise Test Facility was built off of the 10- by 10-Foot Supersonic Wind Tunnel’s Main Compressor and Drive Building. Lewis researchers were able to isolate the fan’s noise during these initial tests by removing the core of the engine. The Lewis test rig drove engines to takeoff tip speeds of 1160 feet per second. The facility was later used to test a series of full-scale model fans and fan noise suppressors to be used with the quiet engine. NASA researchers predicted low-speed single-stage fans without inlet guide vanes and with large spacing between rotors and stators would be quieter. General Electric modified a TF39 turbofan engine by removing the the outer protion of the fan and spacing the blade rows of the inner portion. The tests revealed that the untreated version of the engine generated less noise than was anticipated, and the acoustically treated nacelle substantially reduced engine noise.

Characterizing Facesheet/Core Disbonding in Honeycomb Core Sandwich Structure

NASA Technical Reports Server (NTRS)

Rinker, Martin; Ratcliffe, James G.; Adams, Daniel O.; Krueger, Ronald

2013-01-01

Results are presented from an experimental investigation into facesheet core disbonding in carbon fiber reinforced plastic/Nomex honeycomb sandwich structures using a Single Cantilever Beam test. Specimens with three, six and twelve-ply facesheets were tested. Specimens with different honeycomb cores consisting of four different cell sizes were also tested, in addition to specimens with three different widths. Three different data reduction methods were employed for computing apparent fracture toughness values from the test data, namely an area method, a compliance calibration technique and a modified beam theory method. The compliance calibration and modified beam theory approaches yielded comparable apparent fracture toughness values, which were generally lower than those computed using the area method. Disbonding in the three-ply facesheet specimens took place at the facesheet/core interface and yielded the lowest apparent fracture toughness values. Disbonding in the six and twelve-ply facesheet specimens took place within the core, near to the facesheet/core interface. Specimen width was not found to have a significant effect on apparent fracture toughness. The amount of scatter in the apparent fracture toughness data was found to increase with honeycomb core cell size.

Bent-core fiber structure: Experimental and theoretical studies of fiber stability

NASA Astrophysics Data System (ADS)

Bailey, C.; Gartland, E.; Jakli, A.

2007-03-01

Recent studies have shown that bent core liquid crystals in the B7 and B2 phases can form stable freestanding fibers with a so called ``jelly-roll'' layer configuration, which means that the smectic layers would be arranged in concentric cylindrical shells. This configuration shows layer curvature is necessary for fiber stability. Classically this effect would destabilize the fiber configuration because of the energy cost of layer distortions and surface tension. We propose a model that can predict fiber stability in the experimentally observed range of a few micrometers, by assuming that layer curvature can be stabilized by including a term dealing with the linear divergence of the polarization direction if the polarization is allowed to have a component normal to the smectic layers. We show that this term can stabilize the fiber configuration if its strength is larger than the surface tension. We also propose an entropic model to explain the strength of this term by considering steric effects. Finally we will take results from this model and apply them to better understand experimental findings of bent-core fibers. Financial support by NSF FRG under contract DMS-0456221. Prof. Daniel Phillips, Particia Bauman and Jie Shen at Purdue Univ., Prof. Maria Carme Calderer at Univ. of Minnesota, and Prof. Jonathan Selinger at Kent State Univ. Liou Qiu and Dr. O.D. Lavrentovich, Characterization Facilities, Liquid Crystal Institute, Kent State Univ. Julie Kim and Dr. Quan Li, Chemical Synthesis Facilities, Liquid Crystal Institute, Kent State Univ.

ZPR-6 assembly 7 high {sup 240}Pu core experiments : a fast reactor core with mixed (Pu,U)-oxide fuel and a centeral high{sup 240}Pu zone.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lell, R. M.; Morman, J. A.; Schaefer, R.W.

ZPR-6 Assembly 7 (ZPR-6/7) encompasses a series of experiments performed at the ZPR-6 facility at Argonne National Laboratory in 1970 and 1971 as part of the Demonstration Reactor Benchmark Program (Reference 1). Assembly 7 simulated a large sodium-cooled LMFBR with mixed oxide fuel, depleted uranium radial and axial blankets, and a core H/D near unity. ZPR-6/7 was designed to test fast reactor physics data and methods, so configurations in the Assembly 7 program were as simple as possible in terms of geometry and composition. ZPR-6/7 had a very uniform core assembled from small plates of depleted uranium, sodium, iron oxide,more » U{sub 3}O{sub 8} and Pu-U-Mo alloy loaded into stainless steel drawers. The steel drawers were placed in square stainless steel tubes in the two halves of a split table machine. ZPR-6/7 had a simple, symmetric core unit cell whose neutronic characteristics were dominated by plutonium and {sup 238}U. The core was surrounded by thick radial and axial regions of depleted uranium to simulate radial and axial blankets and to isolate the core from the surrounding room. The ZPR-6/7 program encompassed 139 separate core loadings which include the initial approach to critical and all subsequent core loading changes required to perform specific experiments and measurements. In this context a loading refers to a particular configuration of fueled drawers, radial blanket drawers and experimental equipment (if present) in the matrix of steel tubes. Two principal core configurations were established. The uniform core (Loadings 1-84) had a relatively uniform core composition. The high {sup 240}Pu core (Loadings 85-139) was a variant on the uniform core. The plutonium in the Pu-U-Mo fuel plates in the uniform core contains 11% {sup 240}Pu. In the high {sup 240}Pu core, all Pu-U-Mo plates in the inner core region (central 61 matrix locations per half of the split table machine) were replaced by Pu-U-Mo plates containing 27% {sup 240}Pu in the plutonium

Succession and regulation factors of small eukaryote community composition in a lacustrine ecosystem (Lake Pavin).

PubMed

Lepère, Cécile; Boucher, Delphine; Jardillier, Ludwig; Domaizon, Isabelle; Debroas, Didier

2006-04-01

The structure and dynamics of small eukaryotes (cells with a diameter less than 5 microm) were studied over two consecutive years in an oligomesotrophic lake (Lake Pavin in France). Water samples were collected at 5 and 30 m below the surface; when the lake was stratified, these depths corresponded to the epilimnion and hypolimnion. Changes in small-eukaryote structure were analyzed using terminal restriction fragment length polymorphism (T-RFLP) and cloning and sequencing of the 18S rRNA genes. Terminal restriction fragments from clones were used to reveal the dominant taxa in T-RFLP profiles of the environmental samples. Spumella-like cells (Chrysophyceae) did not dominate the small eukaryote community identified by molecular techniques in lacustrine ecosystems. Small eukaryotes appeared to be dominated by heterotrophic cells, particularly Cercozoa, which represented nearly half of the identified phylotypes, followed by the Fungi-LKM11 group (25%), choanoflagellates (10.3%) and Chrysophyceae (8.9%). Bicosoecida, Cryptophyta, and ciliates represented less than 9% of the community studied. No seasonal reproducibility in temporal evolution of the small-eukaryote community was observed from 1 year to the next. The T-RFLP patterns were related to bottom-up (resources) and top-down (grazing) variables using canonical correspondence analysis. The results showed a strong top-down regulation of small eukaryotes by zooplankton, more exactly, by cladocerans at 5 m and copepods at 30 m. Among bottom-up factors, temperature had a significant effect at both depths. The concentrations of nitrogenous nutrients and total phosphorus also had an effect on small-eukaryote dynamics at 5 m, whereas bacterial abundance and dissolved oxygen played a more important structuring role in the deeper zone.

The Proposal of Key Performance Indicators in Facility Management and Determination the Weights of Significance

NASA Astrophysics Data System (ADS)

Rimbalová, Jarmila; Vilčeková, Silvia

2013-11-01

The practice of facilities management is rapidly evolving with the increasing interest in the discourse of sustainable development. The industry and its market are forecasted to develop to include non-core functions, activities traditionally not associated with this profession, but which are increasingly being addressed by facilities managers. The scale of growth in the built environment and the consequential growth of the facility management sector is anticipated to be enormous. Key Performance Indicators (KPI) are measure that provides essential information about performance of facility services delivery. In selecting KPI, it is critical to limit them to those factors that are essential to the organization reaching its goals. It is also important to keep the number of KPI small just to keep everyone's attention focused on achieving the same KPIs. This paper deals with the determination of weights of KPI of FM in terms of the design and use of sustainable buildings.

Mercury's core evolution

NASA Astrophysics Data System (ADS)

Deproost, Marie-Hélène; Rivoldini, Attilio; Van Hoolst, Tim

2016-10-01

Remote sensing data of Mercury's surface by MESSENGER indicate that Mercury formed under reducing conditions. As a consequence, silicon is likely the main light element in the core together with a possible small fraction of sulfur. Compared to sulfur, which does almost not partition into solid iron at Mercury's core conditions and strongly decreases the melting temperature, silicon partitions almost equally well between solid and liquid iron and is not very effective at reducing the melting temperature of iron. Silicon as the major light element constituent instead of sulfur therefore implies a significantly higher core liquidus temperature and a decrease in the vigor of compositional convection generated by the release of light elements upon inner core formation.Due to the immiscibility in liquid Fe-Si-S at low pressure (below 15 GPa), the core might also not be homogeneous and consist of an inner S-poor Fe-Si core below a thinner Si-poor Fe-S layer. Here, we study the consequences of a silicon-rich core and the effect of the blanketing Fe-S layer on the thermal evolution of Mercury's core and on the generation of a magnetic field.

Thermionic system evaluated test (TSET) facility description

NASA Astrophysics Data System (ADS)

Fairchild, Jerry F.; Koonmen, James P.; Thome, Frank V.

1992-01-01

A consortium of US agencies are involved in the Thermionic System Evaluation Test (TSET) which is being supported by the Strategic Defense Initiative Organization (SDIO). The project is a ground test of an unfueled Soviet TOPAZ-II in-core thermionic space reactor powered by electrical heat. It is part of the United States' national thermionic space nuclear power program. It will be tested in Albuquerque, New Mexico at the New Mexico Engineering Research Institute complex by the Phillips Laboratoty, Sandia National Laboratories, Los Alamos National Laboratory, and the University of New Mexico. One of TSET's many objectives is to demonstrate that the US can operate and test a complete space nuclear power system, in the electrical heater configuration, at a low cost. Great efforts have been made to help reduce facility costs during the first phase of this project. These costs include structural, mechanical, and electrical modifications to the existing facility as well as the installation of additional emergency systems to mitigate the effects of utility power losses and alkali metal fires.

Proton-hole and core-excited states in the semi-magic nucleus 131In82

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taprogge, J.; Jungclaus, A.; Grawe, H.

2016-11-01

The decay of the N = 83 nucleus Cd-131 has been studied at the RIBF facility at the RIKEN Nishina Center. The main purpose of the study was to identify the position of the and proton-hole states and the energies of core-excited configurations in the semi-magic nucleus In-131. From the radiation emitted following the decay, a level scheme of In-131 was established and the feeding to each excited state determined. Similarities between the single-particle transitions observed in the decays of the N = 83 isotones In-132 and Cd-131 are discussed. Finally the excitation energies of several core-excited configurations in In-131more » are compared to QRPA and shell-model calculations.« less

The Yucca Mountain Project prototype air-coring test, U12g tunnel, Nevada test site

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ray, J.M.; Newsom, J.C.

1994-12-01

The Prototype Air-Coring Test was conducted at the Nevada Test Site (NTS) G-Tunnel facility to evaluate standard coring techniques, modified slightly for air circulation, for use in testing at a prospective nuclear waste repository at Yucca Mountain, Nevada. Air-coring technology allows sampling of subsurface lithology with minimal perturbation to ambient characteristic such as that required for exploratory holes near aquifers, environmental applications, and site characterization work. Two horizontal holes were cored, one 50 ft long and the other 150 ft long, in densely welded fractured tuff to simulate the difficult drilling conditions anticipated at Yucca Mountain. Drilling data from sevenmore » holes on three other prototype tests in nonwelded tuff were also collected for comparison. The test was used to establish preliminary standards of performance for drilling and dust collection equipment and to assess procedural efficiencies. The Longyear-38 drill achieved 97% recovery for HQ-size core (-2.5 in.), and the Atlas Copco dust collector (DCT-90) captured 1500 lb of fugitive dust in a mine environment with only minor modifications. Average hole production rates were 6-8 ft per 6-h shift in welded tuff and almost 20 ft per shift on deeper holes in nonwelded tuff. Lexan liners were successfully used to encapsulate core samples during the coring process and protect core properties effectively. The Prototype Air-Coring Test demonstrated that horizontal air coring in fractured welded tuff (to at least 150 ft) can be safely accomplished by proper selection, integration, and minor modification of standard drilling equipment, using appropriate procedures and engineering controls. The test also indicated that rig logistics, equipment, and methods need improvement before attempting a large-scale dry drilling program at Yucca Mountain.« less

Improving Quality of Care in Primary Health-Care Facilities in Rural Nigeria

PubMed Central

Ugo, Okoli; Ezinne, Eze-Ajoku; Modupe, Oludipe; Nicole, Spieker; Kelechi, Ohiri

2016-01-01

Background: Nigeria has a high population density but a weak health-care system. To improve the quality of care, 3 organizations carried out a quality improvement pilot intervention at the primary health-care level in selected rural areas. Objective: To assess the change in quality of care in primary health-care facilities in rural Nigeria following the provision of technical governance support and to document the successes and challenges encountered. Method: A total of 6 states were selected across the 6 geopolitical zones of the country. However, assessments were carried out in 40 facilities in only 5 states. Selection was based on location, coverage, and minimum services offered. The facilities were divided randomly into 2 groups. The treatment group received quality-of-care assessment, continuous feedback, and improvement support, whereas the control group received quality assessment and no other support. Data were collected using the SafeCare Healthcare Standards and managed on the SafeCare Data Management System—AfriDB. Eight core areas were assessed at baseline and end line, and compliance to quality health-care standards was compared. Result: Outcomes from 40 facilities were accepted and analyzed. Overall scores increased in the treatment facilities compared to the control facilities, with strong evidence of improvement (t = 5.28, P = .0004) and 11% average improvement, but no clear pattern of improvement emerged in the control group. Conclusion: The study demonstrated governance support and active community involvement offered potential for quality improvement in primary health-care facilities. PMID:28462280

Metallic nanoshells with semiconductor cores: optical characteristics modified by core medium properties.

PubMed

Bardhan, Rizia; Grady, Nathaniel K; Ali, Tamer; Halas, Naomi J

2010-10-26

It is well-known that the geometry of a nanoshell controls the resonance frequencies of its plasmon modes; however, the properties of the core material also strongly influence its optical properties. Here we report the synthesis of Au nanoshells with semiconductor cores of cuprous oxide and examine their optical characteristics. This material system allows us to systematically examine the role of core material on nanoshell optical properties, comparing Cu(2)O core nanoshells (ε(c) ∼ 7) to lower core dielectric constant SiO(2) core nanoshells (ε(c) = 2) and higher dielectric constant mixed valency iron oxide nanoshells (ε(c) = 12). Increasing the core dielectric constant increases nanoparticle absorption efficiency, reduces plasmon line width, and modifies plasmon energies. Modifying the core medium provides an additional means of tailoring both the near- and far-field optical properties in this unique nanoparticle system.

Academic Rigor: The Core of the Core

ERIC Educational Resources Information Center

Brunner, Judy

2013-01-01

Some educators see the Common Core State Standards as reason for stress, most recognize the positive possibilities associated with them and are willing to make the professional commitment to implementing them so that academic rigor for all students will increase. But business leaders, parents, and the authors of the Common Core are not the only…

Large-scale testing of in-vessel debris cooling through external flooding of the reactor pressure vessel in the CYBL facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chu, T.Y.; Bentz, J.H.; Bergeron, K.D.

1994-04-01

The possibility of achieving in-vessel core retention by flooding the reactor cavity, or the ``flooded cavity``, is an accident management concept currently under consideration for advanced light water reactors (ALWR), as well as for existing light water reactors (LWR). The CYBL (CYlindrical BoiLing) facility is a facility specifically designed to perform large-scale confirmatory testing of the flooded cavity concept. CYBL has a tank-within-a-tank design; the inner 3.7 m diameter tank simulates the reactor vessel, and the outer tank simulates the reactor cavity. The energy deposition on the bottom head is simulated with an array of radiant heaters. The array canmore » deliver a tailored heat flux distribution corresponding to that resulting from core melt convection. The present paper provides a detailed description of the capabilities of the facility, as well as results of recent experiments with heat flux in the range of interest to those required for in-vessel retention in typical ALWRs. The paper concludes with a discussion of other experiments for the flooded cavity applications.« less

Analysis of soft-sediment deformation structures in Neogene fluvio-lacustrine deposits of Çaybağı Formation, Eastern Turkey

NASA Astrophysics Data System (ADS)

Koç Taşgin, Calibe; Türkmen, İbrahim

2009-06-01

During the Neogene, both strike-slip and extensional regimes coexisted in eastern Turkey and, a number of fault-bounded basins associated with the East Anatolian Fault System developed. The Çaybağı Formation (Late Miocene-Early Pliocene) deposited in one of these basins consists of fluvio-lacustrine deposits. Numerous soft-sediment deformation structures are encountered in this formation, particularly in conglomerates, medium- to coarse-grained tuffaceous sandstones and claystones: folded structures (slumps, convolute laminations, and simple recumbent folds), water-escape structures (intruded sands, internal cusps, interpenetrative cusps and sand volcanoes), and load structures (load casts, pseudonodules, flame structures, and pillow structures). These structures are produced by liquefaction and/or fluidization of the unconsolidated sediments during a seismic shock. Consequently, the existence of seismically-induced deformation structures in the Çaybağı Formation and the association with a Neogene intraformational unconformity, growth faults, and reverse faults in the Çaybağı basin attest to the tectonic activity in this area during the Late Miocene and Early Pliocene. The East Anatolian Fault System, in particular the Uluova fault zone, is the most probable seismogenic source. Earthquakes with a magnitude of over 5 in the Richter scale can be postulated.

Decontamination and deactivation of the power burst facility at the Idaho National Laboratory.

PubMed

Greene, Christy Jo

2007-05-01

Successful decontamination and deactivation of the Power Burst Facility located at the Idaho National Laboratory was accomplished through the use of extensive planning, job sequencing, engineering controls, continuous radiological support, and the use of a dedicated group of experienced workers. Activities included the removal and disposal of irradiated fuel, miscellaneous reactor components and debris stored in the canal, removal and disposition of a 15.6 curie Pu:Be start-up source, removal of an irradiated in-pile tube, and the removal of approximately 220,000 pounds of lead that was used as shielding primarily in Cubicle 13. The canal and reactor vessel were drained and water was transferred to an evaporation tank adjacent to the facility. The canal was decontaminated using underwater divers, and epoxy was affixed to the interior surfaces of the canal to contain loose contamination. The support structures and concrete or steel frame walls that form the confinement were left in place. The reactor core was left in place and a carbon steel shielding plate was placed over the reactor core to reduce radiation levels. All low-level waste and mixed low level waste generated as a result of the work activities was characterized and disposed.

Inner Core Structure Behind the PKP Core Phase Triplication

NASA Astrophysics Data System (ADS)

Blom, N.; Paulssen, H.; Deuss, A. F.; Waszek, L.

2015-12-01

Despite its small size, the Earth's inner core plays an important role in the Earth's dynamics. Because it is slowly growing, its structure - and the variation thereof with depth - may reveal important clues about the history of the core, its convection and the resulting geodynamo. Learning more about this structure has been a prime effort in the past decades, leading to discoveries about anisotropy, hemispheres and heterogeneity in the inner core in general. In terms of detailed structure, mainly seismic body waves have contributed to these advances. However, at depths between ~100-200 km, the seismic structure is relatively poorly known. This is a result of the PKP core phase triplication and the existence of strong precursors to PKP phases, whose simultaneous arrival hinders the measurement of inner core waves PKIKP at epicentral distances between roughly 143-148°. As a consequence, the interpretation of deeper structure also remains difficult. To overcome these issues, we stack seismograms in slowness and time, separating PKP and PKIKP phases which arrive simultaneously, but with different slowness. We apply this method to study the inner core's Western hemisphere between South and Central America using paths travelling in the quasi-polar direction between epicentral distances of 140-150°. This enables us to measure PKiKP-PKIKP differential travel times up to greater epicentral distance than has previously been done. The resulting differential travel time residuals increase with epicentral distance, indicating a marked increase in seismic velocity with depth compared to reference model AK135 for the studied polar paths. Assuming a homogeneous outer core, these findings can be explained by either (i) inner core heterogeneity due to an increase in isotropic velocity, or (ii) increase in anisotropy over the studied depth range. Our current data set cannot distinguish between the two hypotheses, but in light of previous work we prefer the latter interpretation.

cFE/CFS (Core Flight Executive/Core Flight System)

NASA Technical Reports Server (NTRS)

Wildermann, Charles P.

2008-01-01

This viewgraph presentation describes in detail the requirements and goals of the Core Flight Executive (cFE) and the Core Flight System (CFS). The Core Flight Software System is a mission independent, platform-independent, Flight Software (FSW) environment integrating a reusable core flight executive (cFE). The CFS goals include: 1) Reduce time to deploy high quality flight software; 2) Reduce project schedule and cost uncertainty; 3) Directly facilitate formalized software reuse; 4) Enable collaboration across organizations; 5) Simplify sustaining engineering (AKA. FSW maintenance); 6) Scale from small instruments to System of Systems; 7) Platform for advanced concepts and prototyping; and 7) Common standards and tools across the branch and NASA wide.

Impact of facility size and profit status on intermediate outcomes in chronic dialysis patients.

PubMed

Frankenfield, D L; Sugarman, J R; Presley, R J; Helgerson, S D; Rocco, M V

2000-08-01

Little information is available regarding the influence of dialysis facility size or profit status on intermediate outcomes in chronic dialysis patients. We have combined data from the Health Care Financing Administration (HCFA) Core Indicators Project; the end-stage renal disease (ESRD) facility survey; and the HCFA On-Line Survey, Certification, and Reporting System to analyze trends in this area. For hemodialysis patients, larger facilities were more likely than smaller facilities to perform dialysis on patients who were younger than 65 years of age, black, or undergoing dialysis 2 years or more (P < 0.001). Nonprofit facilities were more likely to perform dialysis on patients with diabetes mellitus as a cause of ESRD and less likely to perform dialysis on patients with hypertension as a cause of ESRD compared with for-profit units (P < 0.05). By multivariate analysis, larger facility size was modestly associated with a greater Kt/V value and urea reduction ratio, but not with hematocrit or serum albumin values. Facility profit status was not associated with these intermediate outcomes. For peritoneal dialysis patients, there were no significant differences in patient demographics based on facility size. More patients in nonprofit units had been undergoing dialysis 2 or more years than patients in for-profit units (P < 0.05). By univariate analysis, patients in larger facilities were more likely to have an adequacy measure performed than patients from smaller facilities (P < 0.05). There were few substantial differences in intermediate outcomes in chronic dialysis patients based on facility size or profit status.

Metal-silicate Partitioning and Its Role in Core Formation and Composition on Super-Earths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schaefer, Laura; Petaev, M. I.; Sasselov, Dimitar D.

We use a thermodynamic framework for silicate-metal partitioning to determine the possible compositions of metallic cores on super-Earths. We compare results using literature values of the partition coefficients of Si and Ni, as well as new partition coefficients calculated using results from laser shock-induced melting of powdered metal-dunite targets at pressures up to 276 GPa, which approaches those found within the deep mantles of super-Earths. We find that larger planets may have little to no light elements in their cores because the Si partition coefficient decreases at high pressures. The planet mass at which this occurs will depend on themore » metal-silicate equilibration depth. We also extrapolate the equations of state (EOS) of FeO and FeSi alloys to high pressures, and present mass–radius diagrams using self-consistent planet compositions assuming equilibrated mantles and cores. We confirm the results of previous studies that the distribution of elements between mantle and core will not be detectable from mass and radius measurements alone. While observations may be insensitive to interior structure, further modeling is sensitive to compositionally dependent properties, such as mantle viscosity and core freeze-out properties. We therefore emphasize the need for additional high pressure measurements of partitioning as well as EOSs, and highlight the utility of the Sandia Z-facilities for this type of work.« less

The Hominin Sites and Paleolakes Drilling Project (HSPDP): Understanding the paleoenvironmental and paleoclimatic context of human origins through continental drilling

NASA Astrophysics Data System (ADS)

Cohen, Andrew S.; Campisano, Christopher; Asrat, Asfawossen; Arrowsmith, Ramon; Deino, Alan; Feibel, Craig; Hill, Andrew; Kingston, John; Lamb, Henry; Lowenstein, Tim; Olago, Daniel; Bernhart Owen, R.; Renaut, Robin; Schabitz, Frank; Trauth, Martin

2015-04-01

The influence of climate and environmental history on human evolution is an existential question that continues to be hotly debated, in part because of the paucity of high resolution records collected in close proximity to the key fossil and archaeological evidence. To address this issue and transform the scientific debate, the HSPDP was developed to collect lacustrine sediment drill cores from basins in Kenya and Ethiopia that collectively encompass critical time intervals and locations for Plio-Quaternary human evolution in East Africa. After a 17 month campaign, drilling was completed in November, 2014, with over 1750m of core collected from 11 boreholes from five areas (1930m total drilling length, avg. 91% recovery). The sites, from oldest to youngest, include 1) N. Awash, Ethiopia (~3.5-2.9Ma core interval); 2) Baringo-Tugen Hills, Kenya (~3.3-2.5Ma); 3) West Turkana, Kenya (~1.9-1.4Ma); L. Magadi, Kenya (0.8-0Ma) and the Chew Bahir Basin, Ethiopia (~0.5-0Ma). Initial core description (ICD) and sampling for geochronology, geochemistry and paleoecology studies had been completed by mid2014, with the two remaining sites (Magadi and Chew Bahir) scheduled for ICD work in early 2015. Whereas the primary scientific targets were the lacustrine deposits from the hominin-bearing basin depocenters, many intervals of paleosols (representative of low lake stands and probable arid periods) were also encountered in drill cores. Preliminary analyses of drill core sedimentology and geochemistry show both long-term lake level changes and cyclic variability in lake levels, both of which may be indicative of climatic forcing events of interest to paleoanthropologists. Authors of this abstract also include the entire HSPDP field team.

How wet is wet? Strontium isotopes as paleo-lake level indicators in the Chew Bahir basin (S-Ethiopia)

NASA Astrophysics Data System (ADS)

Junginger, A.; Vonhof, H.; Foerster, V. E.; Asrat, A.; Cohen, A. S.; Lamb, H. F.; Schaebitz, F.; Trauth, M. H.

2016-12-01

A major challenge in paleo-anthropology is to understand the impact of climatic changes on human evolution. The Hominin Sites and Paleo-lakes Drilling Project (HSPDP) is currently meeting that challenge by providing records that cover the last 3.7 Ma of paleoenvironmental change all located in close proximity to key paleo-anthropological findings in East Africa. One of the cored climatic archives comes from the dried up Chew Bahir basin in southern Ethiopia, where duplicate sediment cores, each 280 m long, are expected to provide valuable insights about East African environmental variability during the last >500 ka. The lake basins in the eastern branch of the East African Rift System today contain mainly shallow and alkaline lakes. However, paleo-shorelines in the form of wave cut notches, shell beds, and beach ridges are common morphological evidences for deep freshwater lakes that have filled the basins up to their overflow level during pronounced humid episodes, such as the African Humid Period (AHP, 15-5 ka). Unfortunately, further back in time, many of those morphological features disappear due to erosion and the estimation of paleo-water depths depend merely on qualitative proxies from core analyses. We here present a new method that shows high potential to translate qualitative proxy signals from sediment core analyses to quantitative climate signals in the Ethiopian Rift. The method aims at water level reconstruction of multiple paleo-lake episodes in the Chew Bahir basin using strontium isotope ratios (87Sr/86Sr, SIR) in lacustrine fossils and microfossils. SIR preserved in lacustrine fossils reflect the lithology of the drained catchment. The catchment of Chew Bahir consists mainly of Precambrian basement rocks producing high SIR in the lake waters. During humid periods, its catchment enlarged when higher elevated paleo-lakes Abaya, Chamo and Awassa were cascading down into Chew Bahir. These basins drain mainly volcanic rocks producing low SIR. First

Operational Experience of an Open-Access, Subscription-Based Mass Spectrometry and Proteomics Facility.

PubMed

Williamson, Nicholas A

2018-03-01

This paper discusses the successful adoption of a subscription-based, open-access model of service delivery for a mass spectrometry and proteomics facility. In 2009, the Mass Spectrometry and Proteomics Facility at the University of Melbourne (Australia) moved away from the standard fee for service model of service provision. Instead, the facility adopted a subscription- or membership-based, open-access model of service delivery. For a low fixed yearly cost, users could directly operate the instrumentation but, more importantly, there were no limits on usage other than the necessity to share available instrument time with all other users. All necessary training from platform staff and many of the base reagents were also provided as part of the membership cost. These changes proved to be very successful in terms of financial outcomes for the facility, instrument access and usage, and overall research output. This article describes the systems put in place as well as the overall successes and challenges associated with the operation of a mass spectrometry/proteomics core in this manner. Graphical abstract ᅟ.

Operational Experience of an Open-Access, Subscription-Based Mass Spectrometry and Proteomics Facility

NASA Astrophysics Data System (ADS)

Williamson, Nicholas A.

2018-03-01

This paper discusses the successful adoption of a subscription-based, open-access model of service delivery for a mass spectrometry and proteomics facility. In 2009, the Mass Spectrometry and Proteomics Facility at the University of Melbourne (Australia) moved away from the standard fee for service model of service provision. Instead, the facility adopted a subscription- or membership-based, open-access model of service delivery. For a low fixed yearly cost, users could directly operate the instrumentation but, more importantly, there were no limits on usage other than the necessity to share available instrument time with all other users. All necessary training from platform staff and many of the base reagents were also provided as part of the membership cost. These changes proved to be very successful in terms of financial outcomes for the facility, instrument access and usage, and overall research output. This article describes the systems put in place as well as the overall successes and challenges associated with the operation of a mass spectrometry/proteomics core in this manner. [Figure not available: see fulltext.

A versatile cooperative template-directed coating method to construct uniform microporous carbon shells for multifunctional core-shell nanocomposites.