Strength of the San Andreas Fault Zone: Insight From SAFOD Cuttings and Core

NASA Astrophysics Data System (ADS)

Tembe, S.; Lockner, D. A.; Solum, J. G.; Morrow, C. A.; Wong, T.; Moore, D. E.

2005-12-01

Cuttings acquired during drilling of the SAFOD scientific hole near Parkfield, California offer a continuous physical record of the lithology across the San Andreas fault (SAF) zone and provide the only complete set of samples available for laboratory testing. Guided by XRD clay mineral analysis and velocity and gamma logs, we selected washed cuttings from depths spanning the main hole from 1.85 to 3.0 km true vertical depth. Cuttings were chosen to represent primary lithologic units as well as significant shear zones, including candidates for the currently active SAF. To determine frictional properties triaxial sliding tests were conducted on cylindrical granite blocks containing sawcuts inclined at 30° and filled with 1 mm-thick sample gouge layers. Tests were run at constant effective normal stresses of 10 and 40 MPa and constant pore pressure of 1 MPa. Samples were sheared up to 10.4 mm at room temperature and velocities of 1, 0.1 and 0.01 μm/s. Stable sliding behavior and overall strain hardening were observed in all tests. The coefficient of friction typically showed a modest decrease with increasing effective normal stress and mostly velocity strengthening was observed. Preliminary results yield coefficients of friction, μ, which generally fell into two clusters spanning the range of 0.45 to 0.8. The higher values of friction (~0.7 - 0.8) corresponded to quartzofeldspathic samples derived from granodiorites and arkoses encountered in the drill hole. Lower values of friction (0.45 - 0.55) were observed at depth intervals interpreted as shear zones based on enriched clay content, reduced seismic velocities and increased gamma radiation. Arguments for a weak SAF suggest coseismic frictional strength of μ = 0.1 to 0.2 yet the actual fault zone materials studied here appear consistently stronger. At least two important limitations exist for inferring in-situ fault strength from cuttings. (1) Clays and weak minerals are preferentially lost during drilling and

K-Ar constraints on fluid-rock interaction and dissolution-precipitation events within the actively creeping shear zones from SAFOD cores

NASA Astrophysics Data System (ADS)

Ali, S.; Hemming, S. R.; Torgersen, T.; Fleisher, M. Q.; Cox, S. E.; Stute, M.

2009-12-01

The San Andreas Fault Observatory at Depth (SAFOD) was drilled to study the physical and chemical processes responsible for faulting and earthquake generation along an active, plate-bounding fault at depth. SAFOD drill cores show multiple zones of alteration and deformation due to fluid-rock interaction in the fault rocks(Schleicher et al. 2008). In context of fluid studies in the SAFZ, noble gas and potassium measurements were performed on solid samples of sedimentary rocks obtained from drill cores across the fault (3050-4000m-MD). We used a combination of 40Ar/39Ar and K-Ar methods on crushed samples of mudrock with variable amounts of visible slickensides to constrain the degree of resetting of the K-Ar system across the San Andreas Fault zone. 40Ar/39Ar was analyzed from small fragments (sand sized grains) while K-Ar was measured in crushed bulk rock samples (100-250 mg for Ar, and 5-10 mg for K analyses). The apparent 40Ar/39Ar ages based on single step laser fusion of small fragments corresponding to the detrital component in the coarse fraction, show varying ages ranging from the provenance age to <13Ma. Although more data are needed to make detailed comparisons, the apparent K-Ar ages of bulk samples in the fault zone are biased toward authigenic materials contained in the fine fraction, similar to the 40Ar/39Ar ages reported for mineralogical separates from very fine size fractions of samples obtained from 3065.98m-MD and 3294.89m-MD (Schleicher et al., submitted to Geology). The small samples measured for 40Ar/39Ar show scatter in the apparent ages, generally bracketing the bulk ages. However they are picked from sieved portions of the samples, and it is likely that there may be a loss of the younger (finer) material. Detrital provenance ages appear to be 50-60Ma in the Pacific Plate, and 100Ma in the North American Plate. 40Ar/39Ar ages within the SAFZ, as defined by geophysical logs (3200-3400m MD), are dominated by apparent detrital ages of ˜100Ma

Scientific drilling into the San Andreas Fault Zone - an overview of SAFOD's first five years

USGS Publications Warehouse

Zoback, Mark; Hickman, Stephen; Ellsworth, William; ,

2011-01-01

The San Andreas Fault Observatory at Depth (SAFOD) was drilled to study the physical and chemical processes controlling faulting and earthquake generation along an active, plate-bounding fault at depth. SAFOD is located near Parkfield, California and penetrates a section of the fault that is moving due to a combination of repeating microearthquakes and fault creep. Geophysical logs define the San Andreas Fault Zone to be relatively broad (~200 m), containing several discrete zones only 2–3 m wide that exhibit very low P- and S-wave velocities and low resistivity. Two of these zones have progressively deformed the cemented casing at measured depths of 3192 m and 3302 m. Cores from both deforming zones contain a pervasively sheared, cohesionless, foliated fault gouge that coincides with casing deformation and explains the observed extremely low seismic velocities and resistivity. These cores are being now extensively tested in laboratories around the world, and their composition, deformation mechanisms, physical properties, and rheological behavior are studied. Downhole measurements show that within 200 m (maximum) of the active fault trace, the direction of maximum horizontal stress remains at a high angle to the San Andreas Fault, consistent with other measurements. The results from the SAFOD Main Hole, together with the stress state determined in the Pilot Hole, are consistent with a strong crust/weak fault model of the San Andreas. Seismic instrumentation has been deployed to study physics of faulting—earthquake nucleation, propagation, and arrest—in order to test how laboratory-derived concepts scale up to earthquakes occurring in nature.

Lessons Learned From the Analysis of the SAFOD Downhole Instrument Package.

NASA Astrophysics Data System (ADS)

Johnson, Wade; Mencin, David; Mattioli, Glen

2013-04-01

In September of 2008 a downhole instrument package (DIP) consisting of a string of seismometers and tilt meters in isolated pressure vessels (PODs) was installed in the SAFOD main borehole. This package was designed to protect the sensors from the corrosive borehole environment and to operate for two years. The SAFOD borehole is not sealed at the bottom allowing borehole gasses and fluids infiltratration. Previous short-term installations of instruments in the SAFOD main borehole had also failed as a result of corrosion of the wireline cable head. The average failure time for these installations was two weeks. The use of stainless steel tubing connected to the pressure vessels through gas tight fittings was designed to block borehole fluid and gas infiltration of the individual instruments within the PODs. Unfortunately, the DIP completely failed within a month of its installation. In October of 2010, the DIP was removed from the borehole and a failure analysis was performed. This analysis involved to following steps: 1. Analysis of data to understand timeline of failure 2. Remove instrument safely, maintaining integrity of spliced section and documenting any external clues. Test instrument at surface 3. Open PODs in a way that allows for sampling and avoids damaging instruments. 4. Chemical analysis of fluids recovered from splices and PODs. 5. Instrument failure analysis by the instrument manufacturers. The analysis found that there were several design flaws in the DIP. This included the use of motor oil to take up air space in the individual PODs, use of a large number of gas tight seals, lack of internal seals, poorly done solder joints, use of non-temperature rated sensors, and lack of management oversight. The lessons learned from the attempts to instrument the SAFOD borehole are critical to the success of future deep borehole projects.

Joint Inversion of Vp, Vs, and Resistivity at SAFOD

NASA Astrophysics Data System (ADS)

Bennington, N. L.; Zhang, H.; Thurber, C. H.; Bedrosian, P. A.

2010-12-01

Seismic and resistivity models at SAFOD have been derived from separate inversions that show significant spatial similarity between the main model features. Previous work [Zhang et al., 2009] used cluster analysis to make lithologic inferences from trends in the seismic and resistivity models. We have taken this one step further by developing a joint inversion scheme that uses the cross-gradient penalty function to achieve structurally similar Vp, Vs, and resistivity images that adequately fit the seismic and magnetotelluric MT data without forcing model similarity where none exists. The new inversion code, tomoDDMT, merges the seismic inversion code tomoDD [Zhang and Thurber, 2003] and the MT inversion code Occam2DMT [Constable et al., 1987; deGroot-Hedlin and Constable, 1990]. We are exploring the utility of the cross-gradients penalty function in improving models of fault-zone structure at SAFOD on the San Andreas Fault in the Parkfield, California area. Two different sets of end-member starting models are being tested. One set is the separately inverted Vp, Vs, and resistivity models. The other set consists of simple, geologically based block models developed from borehole information at the SAFOD drill site and a simplified version of features seen in geophysical models at Parkfield. For both starting models, our preliminary results indicate that the inversion produces a converging solution with resistivity, seismic, and cross-gradient misfits decreasing over successive iterations. We also compare the jointly inverted Vp, Vs, and resistivity models to borehole information from SAFOD to provide a "ground truth" comparison.

Constraints on the stress state of the San Andreas Fault with analysis based on core and cuttings from San Andreas Fault Observatory at Depth (SAFOD) drilling phases 1 and 2

USGS Publications Warehouse

Tembe, S.; Lockner, D.; Wong, T.-F.

2009-01-01

Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (?? 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault zone. Some models assert that weak gouge and/or high pore pressure exist under static conditions while others consider strength loss or fluid pressure increase due to rapid coseismic fault slip. The present paper is composed of three parts. First, we develop generalized equations, based on and consistent with the Rice (1992) fault zone model to relate stress orientation and magnitude to depth-dependent coefficient of friction and pore pressure. Second, we present temperature-and pressure-dependent friction measurements from wet illite-rich fault gouge extracted from San Andreas Fault Observatory at Depth (SAFOD) phase 1 core samples and from weak minerals associated with the San Andreas Fault. Third, we reevaluate the state of stress on the San Andreas Fault in light of new constraints imposed by SAFOD borehole data. Pure talc (?????0.1) had the lowest strength considered and was sufficiently weak to satisfy weak fault heat flow and stress orientation constraints with hydrostatic pore pressure. Other fault gouges showed a systematic increase in strength with increasing temperature and pressure. In this case, heat flow and stress orientation constraints would require elevated pore pressure and, in some cases, fault zone pore pressure in excess of vertical stress. Copyright 2009 by the American Geophysical Union.

Structure of the San Andreas fault zone at SAFOD from a seismic refraction survey

USGS Publications Warehouse

Hole, J.A.; Ryberg, T.; Fuis, G.S.; Bleibinhaus, F.; Sharma, A.K.

2006-01-01

Refraction traveltimes from a 46-km long seismic survey across the San Andreas Fault were inverted to obtain two-dimensional velocity structure of the upper crust near the SAFOD drilling project. The model contains strong vertical and lateral velocity variations from <2 km/s to ???6 km/s. The Salinian terrane west of the San Andreas Fault has much higher velocity than the Franciscan terrane east of the fault. Salinian basement deepens from 0.8 km subsurface at SAFOD to ???2.5 km subsurface 20 km to the southwest. A strong reflection and subtle velocity contrast suggest a steeply dipping fault separating the Franciscan terrane from the Great Valley Sequence. A low-velocity wedge of Cenozoic sedimentary rocks lies immediately southwest of the San Andreas Fault. This body is bounded by a steep fault just northeast of SAFOD and approaches the depth of the shallowest earthquakes. Multiple active and inactive fault strands complicate structure near SAFOD. Copyright 2006 by the American Geophysical Union.

The character and evolution of fault rocks from the Phase 3 SAFOD core and potential weakening mechanisms along the San Andreas Fault

NASA Astrophysics Data System (ADS)

Holdsworth, Robert; van Diggelen, E. W. E.; Spiers, C. J.; de Bresser, H.; Smith, S. A. F.; Bowen, L.

2010-05-01

In the region of the SAFOD borehole, the San Andreas Fault (SAF) separates two very different geological terranes referred to here as the Salinian and Great Valley blocks (SB, SVB). Whilst material was not collected from the SB-GVB terrane boundary, the cores preserve a diverse range of fault rocks. Not all of these necessarily formed at the same depth, although the amount of exhumation is likely fairly limited. The distribution of deformation is asymmetric, with a broad (200m wide) intensely deformed region developed in the GVB located NE of the terrane boundary; this includes two narrow zones of active creep that have deformed the borehole casing. Microstructurally, low strain domains (most of Core 1, significant parts of Core 3) preserve clear protolith structures, with highly localised evidence for classic upper crustal cataclastic brittle faulting processes and associated fluid flow. The GVB in particular shows clear geological evidence for both fluid pressure and differential stress cycling (variable modes of hydrofacture associated with faults) during seismicity. There is also evidence in all minor faults for the operation of solution-precipitation creep. High strain domains (much of Core 2, parts of Core 3) are characterised by the development of foliated cataclasites and gouge, with variable new growth of fine-grained, interconnected phyllosilicate networks (predominantly smectite-bearing mixed layer clays). Many of the gouges are characterised by the development of S-C fabrics and asymmetric folds. Reworking and reactivation is widespread manifested by: i) the preservation of one or more earlier generations of gouge preserved as clasts; and ii) by the development of later interconnected, polished and striated slip surfaces at low angles or sub-parallel to the foliation. These are coated with thin smectitic phyllosilicate films and are closely associated with the development of lozenge, arrow-head and triangular mineral veins (mostly calcite) precipitated

The microstructural character and evolution of fault rocks from the SAFOD core and potential weakening mechanisms along the San Andreas Fault (Invited)

NASA Astrophysics Data System (ADS)

Holdsworth, R. E.; van Diggelen, E.; Spiers, C.; de Bresser, J. H.; Smith, S. A.

2009-12-01

In the region of the SAFOD borehole, the San Andreas Fault (SAF) separates two very different geological terranes referred to here as the Salinian and Great Valley blocks (SB, GVB). The three sections of core preserve a diverse range of fault rocks and pass through the two currently active, highly localised slipping sections, the so-called ‘10480’ and ‘10830’ fault zones . These coincide with a broader region - perhaps as much as 100m wide - of high strain fault rocks formed at some time in the geological past, but now currently inactive. Both the slipping segments and older high strain zone(s) are developed in the GVB located NE of the terrane boundary. This is likely influenced by the phyllosilicate-rich protolith of the GVB and the large volume of trapped fluid known to exist NE and below the SAF in this region. Microstructurally, lower strain domains (most of Core 1 cutting the SB, significant parts of Core 3 cutting the GVB) preserve clear evidence for classic upper crustal cataclastic brittle faulting processes and associated fluid flow. The GVB in particular shows clear geological evidence for both fluid pressure and differential stress cycling (variable modes of hydrofacture associated with faults) during seismicity. There is also some evidence in all minor faults for the operation of limited amounts of solution-precipitation creep. High strain domains (much of Core 2 cutting the GVB, parts of Core 3 adjacent to the 10830 fault) are characterised by the development of foliated cataclasites and gouge largely due to the new growth of fine-grained phyllosilicate networks (predominantly smectite-bearing mixed layer clays, locally serpentinite, but not talc). The most deformed sections are characterised by the development of shear band fabrics and asymmetric folds. Reworking and reactivation is widespread manifested by: i) the preservation of one or more earlier generations of gouge preserved as clasts; and ii) by the development of later interconnected

Interpretation of S waves generated by near-surface chemical explosions at SAFOD

USGS Publications Warehouse

Pollitz, Fred F.; Ellsworth, William L.; Rubinstein, Justin L.

2015-01-01

A series of near-surface chemical explosions conducted at the San Andreas Fault Observatory at Depth (SAFOD) were recorded by high-frequency downhole receiver arrays in separate experiments in November 2003 and May 2005. The 2003 experiment involved ∼100  kg shots detonated along a 46-km-long line (Hole–Ryberg line) centered on SAFOD and recorded by 32 three-component geophones in the pilot hole between 0.8 and 2.0 km depth. The 2005 experiment involved ∼36  kg shots detonated at Parkfield Area Seismic Observatory (PASO) stations (at ∼1–8  km offset) recorded by 80 three-component geophones in the main hole between the surface and 2.4 km depth. These data sample the downgoing seismic wavefield and constrain the shallow velocity and attenuation structure, as well as the first-order characteristics of the source. Using forward modeling on a velocity structure designed for the near field, both observed P- and S-wave energy for the PASO shots are identified with the travel times expected for direct and/or reflected phases. Larger-offset recordings from shots along the Hole–Ryberg line reveal substantial SV and SH energy, especially southwest of SAFOD from the source as indicated by P-to-S amplitude ratios. The generated SV energy is interpreted to arise chiefly from P-to-S conversions at subhorizontal discontinuities. This provides a simple mechanism for often-observed low P-to-S amplitude ratios from nuclear explosions in the far field, as originating from strong near-field wave conversions.

Borehole Array Observations of Non-Volcanic Tremor at SAFOD

NASA Astrophysics Data System (ADS)

Ellsworth, W. L.; Luetgert, J. H.; Oppenheimer, D. H.

2005-12-01

We report on the observation of non-volcanic tremor made in the San Andreas Fault Observatory at Depth in May, 2005 during the deployment of a multi-level borehole seismic array in the SAFOD main hole. The seismic array consisted of 80 levels of hydraulically-clamped 3-component, 15 Hz omni-directional geophones spaced 15.24 m apart along a 1200 m section of the inclined borehole between 1538 and 2363 m below the ground surface. The array was provided by Paulsson Geophysical Services, Inc. (P/GSI), and recorded at a sample rate of 4000 sps on 24-bit Geode digital recorders provided by Geometrics, Inc. More than 2 TB of continuous data were recorded during the 2-week deployment. Selected local earthquakes and explosions recorded by the array are available at the Northern California Earthquake Data Center, and the entire unedited data set is available as assembled data at the IRIS Data Management Center. Both data sets are currently in the industry standard SEG2 format. Episodes of non-volcanic tremor are common along this reach of the San Andreas Fault according to Nadeau and Dolenc [2004, DOI: 10.1126/science.1107142], with many originating about 30 km southeast of SAFOD beneath the southern end of the Parkfield segment and northern end of the Simmler segment of the fault. We identified tremor episodes using spectrograms routinely produced by the Northern California Seismic Network (http://quake.usgs.gov/cgi-bin/sgrampark.pl) on which they appear as periods of elevated noise relative to the background. A particularly strong tremor episode occurred on May 10, 2005 between 19:39 and 20:00 UTC. In SAFOD, tremor spectral levels exceed the instrumental noise floor to at least 40 Hz. The spatially unaliased recording of the tremor wavefield on the P/GSI array reveal individual phases that can be tracked continuously across the array. The wavefield is composed of both up- and down-going shear waves that form quasi-stationary interference patterns in which areas of

A microstructural study of fault rocks from the SAFOD: Implications for the deformation mechanisms and strength of the creeping segment of the San Andreas Fault

NASA Astrophysics Data System (ADS)

Hadizadeh, Jafar; Mittempergher, Silvia; Gratier, Jean-Pierre; Renard, Francois; Di Toro, Giulio; Richard, Julie; Babaie, Hassan A.

2012-09-01

The San Andreas Fault zone in central California accommodates tectonic strain by stable slip and microseismic activity. We study microstructural controls of strength and deformation in the fault using core samples provided by the San Andreas Fault Observatory at Depth (SAFOD) including gouge corresponding to presently active shearing intervals in the main borehole. The methods of study include high-resolution optical and electron microscopy, X-ray fluorescence mapping, X-ray powder diffraction, energy dispersive X-ray spectroscopy, white light interferometry, and image processing. The fault zone at the SAFOD site consists of a strongly deformed and foliated core zone that includes 2-3 m thick active shear zones, surrounded by less deformed rocks. Results suggest deformation and foliation of the core zone outside the active shear zones by alternating cataclasis and pressure solution mechanisms. The active shear zones, considered zones of large-scale shear localization, appear to be associated with an abundance of weak phases including smectite clays, serpentinite alteration products, and amorphous material. We suggest that deformation along the active shear zones is by a granular-type flow mechanism that involves frictional sliding of microlithons along phyllosilicate-rich Riedel shear surfaces as well as stress-driven diffusive mass transfer. The microstructural data may be interpreted to suggest that deformation in the active shear zones is strongly displacement-weakening. The fault creeps because the velocity strengthening weak gouge in the active shear zones is being sheared without strong restrengthening mechanisms such as cementation or fracture sealing. Possible mechanisms for the observed microseismicity in the creeping segment of the SAF include local high fluid pressure build-ups, hard asperity development by fracture-and-seal cycles, and stress build-up due to slip zone undulations.

A mechanical model of the San Andreas fault and SAFOD Pilot Hole stress measurements

USGS Publications Warehouse

Chery, J.; Zoback, M.D.; Hickman, S.

2004-01-01

Stress measurements made in the SAFOD pilot hole provide an opportunity to study the relation between crustal stress outside the fault zone and the stress state within it using an integrated mechanical model of a transform fault loaded in transpression. The results of this modeling indicate that only a fault model in which the effective friction is very low (<0.1) through the seismogenic thickness of the crust is capable of matching stress measurements made in both the far field and in the SAFOD pilot hole. The stress rotation measured with depth in the SAFOD pilot hole (???28??) appears to be a typical feature of a weak fault embedded in a strong crust and a weak upper mantle with laterally variable heat flow, although our best model predicts less rotation (15??) than observed. Stress magnitudes predicted by our model within the fault zone indicate low shear stress on planes parallel to the fault but a very anomalous mean stress, approximately twice the lithostatic stress. Copyright 2004 by the American Geophysical Union.

Helium measurements of pore fluids obtained from the San Andreas Fault Observatory at Depth (SAFOD, USA) drill cores

NASA Astrophysics Data System (ADS)

Ali, S.; Stute, M.; Torgersen, T.; Winckler, G.; Kennedy, B. M.

2011-02-01

4He accumulated in fluids is a well established geochemical tracer used to study crustal fluid dynamics. Direct fluid samples are not always collectable; therefore, a method to extract rare gases from matrix fluids of whole rocks by diffusion has been adapted. Helium was measured on matrix fluids extracted from sandstones and mudstones recovered during the San Andreas Fault Observatory at Depth (SAFOD) drilling in California, USA. Samples were typically collected as subcores or from drillcore fragments. Helium concentration and isotope ratios were measured 4-6 times on each sample, and indicate a bulk 4He diffusion coefficient of 3.5 ± 1.3 × 10-8 cm2 s-1 at 21°C, compared to previously published diffusion coefficients of 1.2 × 10-18 cm2 s-1 (21°C) to 3.0 × 10-15 cm2 s-1 (150°C) in the sands and clays. Correcting the diffusion coefficient of 4Hewater for matrix porosity (˜3%) and tortuosity (˜6-13) produces effective diffusion coefficients of 1 × 10-8 cm2 s-1 (21°C) and 1 × 10-7 (120°C), effectively isolating pore fluid 4He from the 4He contained in the rock matrix. Model calculations indicate that <6% of helium initially dissolved in pore fluids was lost during the sampling process. Complete and quantitative extraction of the pore fluids provide minimum in situ porosity values for sandstones 2.8 ± 0.4% (SD, n = 4) and mudstones 3.1 ± 0.8% (SD, n = 4).

Correlation of clayey gouge in a surface exposure of serpentinite in the San Andreas Fault with gouge from the San Andreas Fault Observatory at Depth (SAFOD)

NASA Astrophysics Data System (ADS)

Moore, Diane E.; Rymer, Michael J.

2012-05-01

Magnesium-rich clayey gouge similar to that comprising the two actively creeping strands of the San Andreas Fault in drill core from the San Andreas Fault Observatory at Depth (SAFOD) has been identified in a nearby outcrop of serpentinite within the fault zone at Nelson Creek. Each occurrence of the gouge consists of porphyroclasts of serpentinite and sedimentary rocks dispersed in a fine-grained, foliated matrix of Mg-rich smectitic clays. The clay minerals in all three gouges are interpreted to be the product of fluid-assisted, shear-enhanced reactions between quartzofeldspathic wall rocks and serpentinite that was tectonically entrained in the fault from a source in the Coast Range Ophiolite. We infer that the gouge at Nelson Creek connects to one or both of the gouge zones in the SAFOD core, and that similar gouge may occur at depths in between. The special significance of the outcrop is that it preserves the early stages of mineral reactions that are greatly advanced at depth, and it confirms the involvement of serpentinite and the Mg-rich phyllosilicate minerals that replace it in promoting creep along the central San Andreas Fault.

Earthquake source parameters determined by the SAFOD Pilot Hole seismic array

USGS Publications Warehouse

Imanishi, K.; Ellsworth, W.L.; Prejean, S.G.

2004-01-01

We estimate the source parameters of #3 microearthquakes by jointly analyzing seismograms recorded by the 32-level, 3-component seismic array installed in the SAFOD Pilot Hole. We applied an inversion procedure to estimate spectral parameters for the omega-square model (spectral level and corner frequency) and Q to displacement amplitude spectra. Because we expect spectral parameters and Q to vary slowly with depth in the well, we impose a smoothness constraint on those parameters as a function of depth using a linear first-differenfee operator. This method correctly resolves corner frequency and Q, which leads to a more accurate estimation of source parameters than can be obtained from single sensors. The stress drop of one example of the SAFOD target repeating earthquake falls in the range of typical tectonic earthquakes. Copyright 2004 by the American Geophysical Union.

Correlation of clayey gouge in a surface exposure of the San Andreas fault with gouge at depth from SAFOD: Implications for the role of serpentinite in fault mechanics

USGS Publications Warehouse

Moore, Diane E.; Rymer, Michael J.

2012-01-01

Magnesium-rich clayey gouge similar to that comprising the two actively creeping strands of the San Andreas Fault in drill core from the San Andreas Fault Observatory at Depth (SAFOD) has been identified in a nearby outcrop of serpentinite within the fault zone at Nelson Creek. Each occurrence of the gouge consists of porphyroclasts of serpentinite and sedimentary rocks dispersed in a fine-grained, foliated matrix of Mg-rich smectitic clays. The clay minerals in all three gouges are interpreted to be the product of fluid-assisted, shear-enhanced reactions between quartzofeldspathic wall rocks and serpentinite that was tectonically entrained in the fault from a source in the Coast Range Ophiolite. We infer that the gouge at Nelson Creek connects to one or both of the gouge zones in the SAFOD core, and that similar gouge may occur at depths in between. The special significance of the outcrop is that it preserves the early stages of mineral reactions that are greatly advanced at depth, and it confirms the involvement of serpentinite and the Mg-rich phyllosilicate minerals that replace it in promoting creep along the central San Andreas Fault.

Heat Flow in the SAFOD Pilot Hole and Implications for the Strength of the San Andreas Fault

NASA Astrophysics Data System (ADS)

Williams, C. F.; Grubb, F. V.; Galanis, S. P.

2003-12-01

As part of an investigation into the physical properties of the San Andreas fault (SAF) and adjacent crust, detailed thermal measurements have been acquired in the 2.2-km-deep pilot hole for the San Andreas Fault Observatory at Depth (SAFOD), located 1.8 km west of the SAF near Parkfield, California. Precision temperature logs have been combined with thermal conductivity measurements on drill cuttings in a detailed vertical profile of heat flow. The temperature at the bottom of the borehole is 92 ° C, and heat flow from the basement section of the borehole (770 to 2160 m) is 91+/-2 mW m-2. Within the resolution of the measurements, heat flow is constant across the identified faults that intersect the borehole, suggesting that any active fluid flow along these faults is at rates too low to alter the background conductive thermal regime. Heat flow in the SAFOD pilot hole is significantly higher than the 74 mW m-2 average for the Parkfield area reported by Sass et al. (JGR, v. 102, 1997) based on measurements in shallow holes but consistent with five measurements ranging from 84 to 100 mW m-2 near the SAF in Pancho Rico Canyon 20 km to the northwest. Reanalysis of the regional heat flow pattern indicates that high heat flow at the SAFOD site reflects an abrupt increase in heat flow along the SAF and within the Coast Ranges northwest of Parkfield. This transition corresponds to a shallowing of the base of seismicity on the SAF and may be related to a change in the mechanical behavior of the fault near the northern terminus of the M6 1966 Parkfield earthquake rupture. The persistence of elevated heat flow at sites more than 40 km west of the SAFOD pilot hole appears to rule out frictional heating on the SAF as a major source of the high SAFOD value. However, the correlation of along-strike variations in heat flow with changes in rupture patterns and fault characteristics may indicate a previously overlooked connection between laterally heterogeneous frictional

Frictional behavior and BET surface-area changes of SAFOD gouge at intermediate to seismic slip rates

NASA Astrophysics Data System (ADS)

Sawai, Michiyo; Shimamoto, Toshihiko; Mitchell, Thomas; Kitajima, Hiroko; Hirose, Takehiro

2013-04-01

The San Andreas Fault Observatory at Depth (SAFOD) Drilling site is located near the southern end of the creeping section of the San Andreas fault. Experimental studies on the frictional properties of fault gouge from SAFOD drill cores may provide valuable information on the cause of diverse fault motion. We conducted friction experiments on gouge from the southwest deformation zone (SDZ, Phase III core; Hole G-Run 2-Section 8) where creep is confirmed by ongoing borehole casing deformation, at intermediate to high slip rates (10-5 to 1.3 m/s), at a normal stress of about 1 MPa, and under both dry (room humidity) and wet (25 wt% of H2O added, drained tests) conditions. Experiments were performed with two rotary-shear friction apparatuses. One gram of gouge was placed between specimens of Belfast gabbro 25 mm in diameter surrounded by a Teflon sleeve to confine the gouge. Slip rate was first decreased and then increased in a step-wise manner to obtain the steady-state friction at intermediate slip rates. The friction coefficient increases from about 0.13 to 0.37 as the slip rate increases from 0.8 x 10-5 to 9.7 x 10-3 m/s. Our results agree with frictional strength measured at higher effective normal stress (100 MPa) by the Brown University group in the same material. Data shows pronounced velocity strengthening at intermediate slip rates, which is unfavorable for rupture nucleation and may be a reason for having creep behavior. On the other hand, the steady-state friction markedly decreases at high velocity, and such weakening may allow earthquake rupture to propagate into the creeping section, once the intermediate strength barrier is overcome. Gouge temperature, measured at the edge of the stationary sample during seismic fault motion, increased to around 175oC under dry conditions, but increased up to 100oC under wet conditions. We measured BET surface area of gouge before and after deformation to determine the energy used for grain crushing. The initial

Determining SAFOD area microearthquake locations solely with the Pilot Hole seismic array data

NASA Astrophysics Data System (ADS)

Oye, Volker; Chavarria, J. Andres; Malin, Peter E.

2004-05-01

In August 2002, an array of 32 three-component geophones was installed in the San Andreas Fault Observatory at Depth (SAFOD) Pilot Hole (PH) at Parkfield, CA. As an independent test of surface-observation-based microearthquake locations, we have located such events using only data recorded on the PH array. We then compared these locations with locations from a combined set of PH and Parkfield High Resolution Seismic Network (HRSN) observations. We determined the uncertainties in the locations as they relate to errors in the travel time picks and the velocity model by the bootstrap method. Based on the PH and combined locations, we find that the ``C2'' cluster to the northeast of the PH has the smallest location uncertainties. Events in this cluster also have the most similar waveforms and largest magnitudes. This confirms earlier suggestions that the C2 cluster is a promising target for the SAFOD Main Hole.

Preseismic Velocity Changes Observed from Active Source Monitoringat the Parkfield SAFOD Drill Site

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

Daley, Thomas; Niu, Fenglin; Silver, Paul G.

2008-06-10

Measuring stress changes within seismically active fault zones has been a long-sought goal of seismology. Here we show that such stress changes are measurable by exploiting the stress dependence of seismic wave speed from an active source cross-well experiment conducted at the SAFOD drill site. Over a two-month period we observed an excellent anti-correlation between changes in the time required for an S wave to travel through the rock along a fixed pathway--a few microseconds--and variations in barometric pressure. We also observed two large excursions in the traveltime data that are coincident with two earthquakes that are among those predictedmore » to produce the largest coseismic stress changes at SAFOD. Interestingly, the two excursions started approximately 10 and 2 hours before the events, respectively, suggesting that they may be related to pre-rupture stress induced changes in crack properties, as observed in early laboratory studies.« less

A microstructural study of SAFOD gouge from actively creeping San Andreas Fault zone; Implications for shear localization models

NASA Astrophysics Data System (ADS)

Blackburn, E. D.; Hadizadeh, J.; Babaie, H. A.

2009-12-01

The prevailing models of shear localization in fault gouges are mainly based on experimental aggregates that necessarily neglect the effects of chemical and mechanical maturation with time. The SAFOD cores have provided a chance to test whether cataclasis as a deformation mechanism and factors such as porosity and particle size, critical in some existing shear localization models continue to be critical in mature gouges. We studied a core sample from 3194m MD in the SAFOD phase 3, which consists of intensely foliated shale-siltstone cataclasites in contact with less deformed shale. Microstructures were studied in 3 perpendicular planes with reference to foliation using high resolution scanning electron microscopy, cathodoluminescence imaging, X-ray fluorescence mapping, and energy dispersive X-ray spectroscopy. The cataclastic foliation, recognizable at length scales >100 μm, is primarily defined by bands of clay gouge with distinct microstructure, clay content, and porosity. Variations in elemental composition and porosity of the clay gouge were measured continuously across the foliation. Prominent features within the foliation bands include lens-shaped clusters of highly brecciated and veined siltstone fragments, pyrite smears, and pyrite-cemented cataclasites. The microstructural relations and chemical data provide clear evidence of multiple episodes of veining and deformation with some possibility of relative age determination for the episodes. There is evidence of syn-deformation hydrothermal changes including growth and brittle shear of pyrite, alteration of host shale clays to illite-smectite clays and Fe-rich smectite. Evidence of grain-boundary corrosion of non-clay mineral fragments suggests pressure solution creep. The gouge porosity estimates varied from 0-18% (about 3% in less deformed shale) with the highest value in the bands with abundant siltstone fragments. The banding is mechanically significant since it pervasively segregates the gouge into

Coring Sample Acquisition Tool

NASA Technical Reports Server (NTRS)

Haddad, Nicolas E.; Murray, Saben D.; Walkemeyer, Phillip E.; Badescu, Mircea; Sherrit, Stewart; Bao, Xiaoqi; Kriechbaum, Kristopher L.; Richardson, Megan; Klein, Kerry J.

2012-01-01

A sample acquisition tool (SAT) has been developed that can be used autonomously to sample drill and capture rock cores. The tool is designed to accommodate core transfer using a sample tube to the IMSAH (integrated Mars sample acquisition and handling) SHEC (sample handling, encapsulation, and containerization) without ever touching the pristine core sample in the transfer process.

Core sample extractor

NASA Technical Reports Server (NTRS)

Akins, James; Cobb, Billy; Hart, Steve; Leaptrotte, Jeff; Milhollin, James; Pernik, Mark

1989-01-01

The problem of retrieving and storing core samples from a hole drilled on the lunar surface is addressed. The total depth of the hole in question is 50 meters with a maximum diameter of 100 millimeters. The core sample itself has a diameter of 60 millimeters and will be two meters in length. It is therefore necessary to retrieve and store 25 core samples per hole. The design utilizes a control system that will stop the mechanism at a certain depth, a cam-linkage system that will fracture the core, and a storage system that will save and catalogue the cores to be extracted. The Rod Changer and Storage Design Group will provide the necessary tooling to get into the hole as well as to the core. The mechanical design for the cam-linkage system as well as the conceptual design of the storage device are described.

Elemental Geochemistry of Samples From Fault Segments of the San Andreas Fault Observatory at Depth (SAFOD) Drill Hole

NASA Astrophysics Data System (ADS)

Tourscher, S. N.; Schleicher, A. M.; van der Pluijm, B. A.; Warr, L. N.

2006-12-01

Elemental geochemistry of mudrock samples from phase 2 drilling of the San Andreas Fault Observatory at Depth (SAFOD) is presented from bore hole depths of 3066 m to 3169 m and from 3292 m to 3368 m, which contain a creeping section and main trace of the fault, respectively. In addition to preparation and analysis of whole rock sample, fault grains with neomineralized, polished surfaces were hand picked from well-washed whole rock samples, minimizing the potential contamination from drilling mud and steel shavings. The separated fractions were washed in deionized water, powdered using a mortar and pestle, and analyzed using an Inductively Coupled Plasma- Optical Emission Spectrometer for major and minor elements. Based on oxide data results, systematic differences in element concentrations are observed between the whole rock and fault rock. Two groupings of data points are distinguishable in the regions containing the main trace of the fault, a shallow part (3292- 3316 m) and a deeper section (3320-3368 m). Applying the isocon method, assuming Zr and Ti to be immobile elements in these samples, indicates a volume loss of more than 30 percent in the shallow part and about 23 percent in the deep part of the main trace. These changes are minimum estimates of fault-related volume loss, because the whole rock from drilling samples contains variable amount of fault rock as well. Minimum estimates for volume loss in the creeping section of the fault are more than 50 percent when using the isocon method, comparing whole rock to plucked fault rock. The majority of the volume loss in the fault rocks is due to the dissolution and loss of silica, potassium, aluminum, sodium and calcium, whereas (based on oxide data) the mineralized surfaces of fractures appear to be enriched in Fe and Mg. The large amount of element mobility within these fault traces suggests extensive circulation of hydrous fluids along fractures that was responsible for progressive dissolution and leaching

Implications of Microstructural Studies of the SAFOD Gouge for the Strength and Deformation Mechanisms in the Creeping Segment of the San Andreas Fault

NASA Astrophysics Data System (ADS)

Hadizadeh, J.; Gratier, J. L.; Mittempergher, S.; Renard, F.; Richard, J.; di Toro, G.; Babaie, H. A.

2010-12-01

The San Andreas Fault zone (SAF) in the vicinity of the San Andreas Fault Observatory at Depth (SAFOD)in central California is characterized by an average 21 mm/year aseismic creep and strain release through repeating M<3 earthquakes. Seismic inversion studies indicate that the ruptures occur on clusters of stationary patches making up 1% or less of the total fault surface area. The existence of these so-called asperity patches, although not critical in determining the fault strength, suggests interaction of different deformation mechanisms. What are the deformation mechanisms, and how do the mechanisms couple and factor into the current strength models for the SAF? The SAFOD provides core samples and geophysical data including cores from two shear zones where the main borehole casing is deforming. The studies so far show a weak fault zone with about 200m of low-permeability damage zone without anomalous temperature or high fluid pressure (Zoback et al. EOS 2010). To answer the above questions, we studied core samples and thin sections ranging in measured depths (MD) from 3059m to 3991m including gouge from borehole casing deformation zones. The methods of study included high resolution scanning and transmission electron microscopy, cathodoluminescence imaging, X-ray fluorescence mapping, and energy dispersive X-ray spectroscopy. The microstructural and analytical data suggest that deformation is by a coupling of cataclastic flow and pressure solution accompanied by widespread alteration of feldspar to clay minerals and other neomineralizations. The clay contents of the gouge and streaks of serpentinite are not uniformly distributed, but weakness of the creeping segment is likely to be due to intrinsically low frictional strength of the fault material. This conclusion, which is based on the overall ratio of clay/non-clay constituents and the presence of talc in the actively deforming zones, is consistent with the 0.3-0.45 coefficient of friction for the drill

Refined images of the crust around the SAFOD drill site derived from combined active and passive seismic experiment data

NASA Astrophysics Data System (ADS)

Roecker, S.; Thurber, C.; Shuler, A.; Liu, Y.; Zhang, H.; Powell, L.

2005-12-01

Five years of effort collecting and analyzing earthquake and explosion data in the vicinity of the SAFOD drill site culminated in the determination of the final trajectory for summer 2005's Phase 2 drilling. The trajectory was defined to optimize the chance of reaching one of two adjacent M2 "target earthquake" fault patches, whose centroids are separated horizontally by about 50 meters, with one or more satellite coreholes planned for Phase 3 drilling in summer 2007. Some of the most critical data for the final targeting were explosion data recorded on a Paulsson Geophysical Services, Inc., 80-element 3-component borehole string and earthquake data recorded on a pair of 3-component Duke University geophones in the SAFOD borehole. We are now utilizing the full 5-year dataset to refine our knowledge of three-dimensional (3D) crustal structure, wave propagation characteristics, and earthquake locations around SAFOD. These efforts are proceeding in parallel in several directions. Improved picks from a careful reanalysis of shear waves observed on the PASO array will be used in deriving an improved tomographic 3D wavespeed model. We are using finite-difference waveform modeling to investigate waveform complexity for earthquakes in and near the target region, including fault-zone head waves and strong secondary S-wave arrivals. A variety of waveform imaging methods are being applied to image fine-scale 3D structure and subsurface scatterers, including fault zones. In the process, we aim to integrate geophysical logging and geologic observations with our models to try to associate the target region earthquake activity, which is occurring on two fault strands about 280 meters apart, with shear zones encountered in the SAFOD Phase-2 borehole. These observations will be agumented and the target earthquake locations further refined over the next 2 years through downhole and surface recording of natural earthquakes and surface shots conducted at PASO station locations.

Heat flow in the SAFOD pilot hole and implications for the strength of the San Andreas Fault

USGS Publications Warehouse

Williams, C.F.; Grubb, F.V.; Galanis, S.P.

2004-01-01

Detailed thermal measurements have been acquired in the 2.2-km-deep SAFOD pilot hole, located 1.8 km west of the SAF near Parkfield, California. Heat flow from the basement section of the borehole (770 to 2160 m) is 91 mW m-2, higher than the published 74 mW m -2 average for the Parkfield area. Within the resolution of the measurements, heat flow is constant across faults that intersect the borehole, suggesting that fluid flow does not alter the conductive thermal regime. Reanalysis of regional heat flow reveals an increase in heat flow along the SAF northwest of Parkfield. This transition corresponds to a shallowing base of seismicity and a change in fault behavior near the northern terminus of the M6 1966 Parkfield earthquake rupture. The persistence of elevated heat flow in the Coast Ranges to the west appears to rule out frictional heating on the SAF as the source of the SAFOD value.

The SAFOD Pilot Hole seismic array: Wave propagation effects as a function of sensor depth and source location

NASA Astrophysics Data System (ADS)

Chavarria, J. Andres; Malin, Peter E.; Shalev, Eylon

2004-05-01

In July 2002 we installed a vertical array of seismometers in the San Andreas Fault Observatory at Depth (SAFOD) Pilot Hole (PH). The bottom of this 32 level, 1240 m long array of 3- components is located at a depth of ~2100 m below ground. Surface-explosion and microearthquake seismograms recorded by the array give valuable insights into the structure of the SAFOD site. The ratios of P- and S-wave velocities (Vp/Vs) along the array suggest the presence of two faults intersecting the PH. The Vp/Vs ratios also depend on source location, with high values to the NW, and lower ones to the SE, correlating with high and low creep rates along the SAF, respectively. Since higher ratios can be produced by increasing fluid saturation, we suggest that this effect might account for both our observations and their correlation with the creep distribution.

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...

Origin and significance of clay-coated fractures in mudrock fragments of the SAFOD borehole (Parkfield, California)

USGS Publications Warehouse

Schleicher, A.M.; van der Pluijm, B.A.; Solum, J.G.; Warr, L.N.

2006-01-01

The clay mineralogy and texture of rock fragments from the SAFOD borehole at 3067 m and 3436 m measured depth (MD) was investigated by electron microscopy (SEM, TEM) and X-ray-diffraction (XRD). The washed and ultrasonically cleaned samples show slickenfiber striations and thin films of Ca-K bearing smectite that are formed on polished fault surfaces, along freshly opened fractures and within adjacent mineralized veins. The cation composition and hydration behavior of these films differ from the Namontmorillonite of the fresh bentonite drilling mud, although there is more similarity with circulated mud recovered from 3479 m MD. We propose that these thin film smectite precipitates formed by natural nucleation and crystal growth during fault creep, probably associated with the shallow circulation of low temperature aqueous fluids along this shallow portion of the San Andreas Fault. Copyright 2006 by the American Geophysical Union.

Description of core samples returned by Apollo 12

NASA Technical Reports Server (NTRS)

Lindsay, J. F.; Fryxell, R.

1971-01-01

Three core samples were collected by the Apollo 12 astronauts. Two are single cores, one of which (sample 12026) was collected close to the lunar module during the first extravehicular activity period and is 19.3 centimeters long. The second core (sample 12027) was collected at Sharp Crater during the second extravehicular activity period and is 17.4 centimeters long. The third sample is a double core (samples 12025 and 12028), which was collected near Halo Crater during the second extravehicular activity period. Unlike the other cores, the double-drive-tube core sample has complex layering with at least 10 clearly defined stratigraphic units. This core sample is approximately 41 centimeters long.

Effects of fluid-rock interactions on faulting within active fault zones - evidence from fault rock samples retrieved from international drilling projects

NASA Astrophysics Data System (ADS)

Janssen, C.; Wirth, R.; Kienast, M.; Yabe, Y.; Sulem, J.; Dresen, G. H.

2015-12-01

Chemical and mechanical effects of fluids influence the fault mechanical behavior. We analyzed fresh fault rocks from several scientific drilling projects to study the effects of fluids on fault strength. For example, in drill core samples on a rupture plane of an Mw 2.2 earthquake in a deep gold mine in South Africa the main shock occurred on a preexisting plane of weakness that was formed by fluid-rock interaction (magnesiohornblende was intensively altered to chlinochlore). The plane acted as conduit for hydrothermal fluids at some time in the past. The chemical influence of fluids on mineralogical alteration and geomechanical processes in fault core samples from SAFOD (San Andreas Fault Observatory at Depth) is visible in pronounced dissolution-precipitation processes (stylolites, solution seams) as well as in the formation of new phases. Detrital quartz and feldspar grains are partially dissolved and replaced by authigenic illite-smectite (I-S) mixed-layer clay minerals. Transmission Electron Microscopy (TEM) imaging of these grains reveals that the alteration processes and healing were initiated within pores and small intra-grain fissures. Newly formed phyllosilicates growing into open pore spaces likely reduced the fluid permeability. The mechanical influence of fluids is indicated by TEM observations, which document open pores that formed in-situ in the gouge material during or after deformation. Pores were possibly filled with formation water and/or hydrothermal fluids suggesting elevated fluid pressure preventing pore collapse. Fluid-driven healing of fractures in samples from SAFOD and the DGLab Gulf of Corinth project is visible in cementation. Cathodoluminescence microscopy (CL) reveals different generations of calcite veins. Differences in CL-colors suggest repeated infiltration of fluids with different chemical composition from varying sources (formation and meteoric water).

Joint inversion for Vp, Vs, and Vp/Vs at SAFOD, Parkfield, California

USGS Publications Warehouse

Zhang, H.; Thurber, C.; Bedrosian, P.

2009-01-01

We refined the three-dimensional (3-D) Vp, Vs and Vp/Vs models around the San Andreas Fault Observatory at Depth (SAFOD) site using a new double-difference (DD) seismic tomography code (tomoDDPS) that simultaneously solves for earthquake locations and all three velocity models using both absolute and differential P, S, and S-P times. This new method is able to provide a more robust Vp/Vs model than that from the original DD tomography code (tomoDD), obtained simply by dividing Vp by Vs. For the new inversion, waveform cross-correlation times for earthquakes from 2001 to 2002 were also used, in addition to arrival times from earthquakes and explosions in the region. The Vp values extracted from the model along the SAFOD trajectory match well with the borehole log data, providing in situ confirmation of our results. Similar to previous tomographic studies, the 3-D structure around Parkfield is dominated by the velocity contrast across the San Andreas Fault (SAF). In both the Vp and Vs models, there is a clear low-velocity zone as deep as 7 km along the SAF trace, compatible with the findings from fault zone guided waves. There is a high Vp/Vs anomaly zone on the southwest side of the SAF trace that is about 1-2 km wide and extends as deep as 4 km, which is interpreted to be due to fluids and fractures in the package of sedimentary rocks abutting the Salinian basement rock to the southwest. The relocated earthquakes align beneath the northeast edge of this high Vp/Vs zone. We carried out a 2-D correlation analysis for an existing resistivity model and the corresponding profiles through our model, yielding a classification that distinguishes several major lithologies. ?? 2009 by the American Geophysical Union.

Evaluating Core Quality for a Mars Sample Return Mission

NASA Technical Reports Server (NTRS)

Weiss, D. K.; Budney, C.; Shiraishi, L.; Klein, K.

2012-01-01

Sample return missions, including the proposed Mars Sample Return (MSR) mission, propose to collect core samples from scientifically valuable sites on Mars. These core samples would undergo extreme forces during the drilling process, and during the reentry process if the EEV (Earth Entry Vehicle) performed a hard landing on Earth. Because of the foreseen damage to the stratigraphy of the cores, it is important to evaluate each core for rock quality. However, because no core sample return mission has yet been conducted to another planetary body, it remains unclear as to how to assess the cores for rock quality. In this report, we describe the development of a metric designed to quantitatively assess the mechanical quality of any rock cores returned from Mars (or other planetary bodies). We report on the process by which we tested the metric on core samples of Mars analogue materials, and the effectiveness of the core assessment metric (CAM) in assessing rock core quality before and after the cores were subjected to shocking (g forces representative of an EEV landing).

Joint Inversion of Body-Wave Arrival Times and Surface-Wave Dispersion Data for Three-Dimensional Seismic Velocity Structure Around SAFOD

NASA Astrophysics Data System (ADS)

Zhang, H.; Thurber, C. H.; Maceira, M.; Roux, P.

2013-12-01

The crust around the San Andreas Fault Observatory at depth (SAFOD) has been the subject of many geophysical studies aimed at characterizing in detail the fault zone structure and elucidating the lithologies and physical properties of the surrounding rocks. Seismic methods in particular have revealed the complex two-dimensional (2D) and three-dimensional (3D) structure of the crustal volume around SAFOD and the strong velocity reduction in the fault damage zone. In this study we conduct a joint inversion using body-wave arrival times and surface-wave dispersion data to image the P-and S-wave velocity structure of the upper crust surrounding SAFOD. The two data types have complementary strengths - the body-wave data have good resolution at depth, albeit only where there are crossing rays between sources and receivers, whereas the surface waves have very good near-surface resolution and are not dependent on the earthquake source distribution because they are derived from ambient noise. The body-wave data are from local earthquakes and explosions, comprising the dataset analyzed by Zhang et al. (2009). The surface-wave data are for Love waves from ambient noise correlations, and are from Roux et al. (2011). The joint inversion code is based on the regional-scale version of the double-difference (DD) tomography algorithm tomoDD. The surface-wave inversion code that is integrated into the joint inversion algorithm is from Maceira and Ammon (2009). The propagator matrix solver in the algorithm DISPER80 (Saito, 1988) is used for the forward calculation of dispersion curves from layered velocity models. We examined how the structural models vary as we vary the relative weighting of the fit to the two data sets and in comparison to the previous separate inversion results. The joint inversion with the 'optimal' weighting shows more clearly the U-shaped local structure from the Buzzard Canyon Fault on the west side of SAF to the Gold Hill Fault on the east side.

Structure of the California Coast Ranges and San Andreas Fault at SAFOD from seismic waveform inversion and reflection imaging

USGS Publications Warehouse

Bleibinhaus, F.; Hole, J.A.; Ryberg, T.; Fuis, G.S.

2007-01-01

A seismic reflection and refraction survey across the San Andreas Fault (SAF) near Parkfield provides a detailed characterization of crustal structure across the location of the San Andreas Fault Observatory at Depth (SAFOD). Steep-dip prestack migration and frequency domain acoustic waveform tomography were applied to obtain highly resolved images of the upper 5 km of the crust for 15 km on either side of the SAF. The resulting velocity model constrains the top of the Salinian granite with great detail. Steep-dip reflection seismic images show several strong-amplitude vertical reflectors in the uppermost crust near SAFOD that define an ???2-km-wide zone comprising the main SAF and two or more local faults. Another prominent subvertical reflector at 2-4 km depth ???9 km to the northeast of the SAF marks the boundary between the Franciscan terrane and the Great Valley Sequence. A deep seismic section of low resolution shows several reflectors in the Salinian crust west of the SAF. Two horizontal reflectors around 10 km depth correlate with strains of seismicity observed along-strike of the SAF. They represent midcrustal shear zones partially decoupling the ductile lower crust from the brittle upper crust. The deepest reflections from ???25 km depth are interpreted as crust-mantle boundary. Copyright 2007 by the American Geophysical Union.

Real-Time Fluid and Gas Monitoring During Drilling of the SAFOD Main Hole in Parkfield, CA.

NASA Astrophysics Data System (ADS)

Wiersberg, T.; Erzinger, J.

2005-12-01

Little is known about the role and origin of fluids and gases associated with the San Andreas Fault zone (SAF). To gain information on fluids and gases at depth, we performed real-time mud gas monitoring during drilling of the SAFOD (San Andreas Fault Observatory at Depth) Pilot Hole (PH) and Main Hole (MH). Gas extracted from returning drill mud was piped into a nearby laboratory trailer and analyzed on-line. Permanent gases were detected using a portable mass spectrometer, hydrocarbons with a gas chromatograph, and the 222Rn-activity with a Lucas-Cell detector. When significant amounts of non-atmospheric gases were detected, off-line gas samples were collected from the gas line for further isotope studies. The SAFOD PH and MH were drilled in only a few meter distance, but in contrast to the straight PH, which penetrates through 768 m of sediments into granites down to 2168 m target depth (TD), the nearby MH is deviated towards the SAF and returns into sedimentary strata below 1930 m. The MH drilled sedimentary rocks down to 3987 m TD, approximately 45 m northeast of the surface trace of the SAF. From surface to 1930 m, the depth distribution of gas is similar for SAFOD PH and MH. Shear zones, identified by geophysical logging, are often characterized by elevated concentrations of CH4, CO2, H2, Rn, and He. The same gases were found in the MH below 1930 m, but their concentrations were, with the exception of He, significantly higher: CH4, CO2, and H2 sometimes reach several volume percent. Generally, the gas composition is partly controlled by the lithology. Variation in the methane concentration in several depth intervals reflects the changes in lithology from low gas abundance in clays and silts to more gas rich shales, which are the source rocks for hydrocarbons. Highly porous and permeable sandstone yield the highest concentrations of hydrocarbons (up to 15 vol% methane), and may be regarded as reservoir rocks. We interpret high radon activities in mud gas as

ROPEC - ROtary PErcussive Coring Drill for Mars Sample Return

NASA Technical Reports Server (NTRS)

Chu, Philip; Spring, Justin; Zacny, Kris

2014-01-01

The ROtary Percussive Coring Drill is a light weight, flight-like, five-actuator drilling system prototype designed to acquire core material from rock targets for the purposes of Mars Sample Return. In addition to producing rock cores for sample caching, the ROPEC drill can be integrated with a number of end effectors to perform functions such as rock surface abrasion, dust and debris removal, powder and regolith acquisition, and viewing of potential cores prior to caching. The ROPEC drill and its suite of end effectors have been demonstrated with a five degree of freedom Robotic Arm mounted to a mobility system with a prototype sample cache and bit storage station.

A core handling device for the Mars Sample Return Mission

NASA Technical Reports Server (NTRS)

Gwynne, Owen

1989-01-01

A core handling device for use on Mars is being designed. To provide a context for the design study, it was assumed that a Mars Rover/Sample Return (MRSR) Mission would have the following characteristics: a year or more in length; visits by the rover to 50 or more sites; 100 or more meter-long cores being drilled by the rover; and the capability of returning about 5 kg of Mars regolith to Earth. These characteristics lead to the belief that in order to bring back a variegated set of samples that can address the range of scientific objetives for a MRSR mission to Mars there needs to be considerable analysis done on board the rover. Furthermore, the discrepancy between the amount of sample gathered and the amount to be returned suggests that there needs to be some method of choosing the optimal set of samples. This type of analysis will require pristine material-unaltered by the drilling process. Since the core drill thermally and mechanically alters the outer diameter (about 10 pct) of the core sample, this outer area cannot be used. The primary function of the core handling device is to extract subsamples from the core and to position these subsamples, and the core itself if needed, with respect to the various analytical instruments that can be used to perform these analyses.

Comprehensive study of thermal properties of lunar core samples

NASA Technical Reports Server (NTRS)

Langseth, M. G.; Horath, K.

1975-01-01

The feasibility of a technique for measuring the thermal conductivity of lunar core samples was investigated. The thermal conduction equation for a composite cylinder was solved to obtain a mathematical expression for the surface temperature of the core tube filled with lunar material. The sample is heated by radiation from the outside at a known rate, the variation of the temperature at the surface of the core tube is measured, and the thermal conductivity determined by comparing the observed temperature with the theoretically expected one. The apparatus used in the experiment is described.

Description, dissection, and subsampling of Apollo 14 core sample 14230

NASA Technical Reports Server (NTRS)

Fryxell, R.; Heiken, G.

1971-01-01

Core sample 14230, collected at Triplet Crater near the Fra Mauro landing site of the Apollo 14 mission, was dissected in greater detail than any previous core. Sediment from the actual lunar surface was missing, and 6.7 grams of sediment were removed from the base of the core for a portion of the biotest prime sample. Upper and lower portions of the original 70.7-gram core (12.5 centimeters long) were fractured excessively but not mixed stratigraphically. Three major morphologic units and 11 subdivisions were recognized. Dissection provided 55 subsamples in addition to three others made by removing longitudinal sections of the core impregnated with n-butyl methacrylate for use as a permanent documentary record and for studies requiring particles of known orientation.

On the origin of mixed-layered clay minerals from the San Andreas Fault at 2.5-3 km vertical depth (SAFOD drillhole at Parkfield, California)

NASA Astrophysics Data System (ADS)

Schleicher, A. M.; Warr, L. N.; van der Pluijm, B. A.

2009-02-01

A detailed mineralogical study is presented of the matrix of mudrocks sampled from spot coring at three key locations along the San Andreas Fault Observatory at depth (SAFOD) drill hole. The characteristics of authigenic illite-smectite (I-S) and chlorite-smectite (C-S) mixed-layer mineral clays indicate a deep diagenetic origin. A randomly ordered I-S mineral with ca. 20-25% smectite layers is one of the dominant authigenic clay species across the San Andreas Fault zone (sampled at 3,066 and 3,436 m measured depths/MD), whereas an authigenic illite with ca. 2-5% smectite layers is the dominant phase beneath the fault (sampled at 3,992 m MD). The most smectite-rich mixed-layered assemblage with the highest water content occurs in the actively deforming creep zone at ca. 3,300-3,353 m (true vertical depth of ca. 2.7 km), with I-S (70:30) and C-S (50:50). The matrix of all mudrock samples show extensive quartz and feldspar (both plagioclase and K-feldspar) dissolution associated with the crystallization of pore-filling clay minerals. However, the effect of rock deformation in the matrix appears only minor, with weak flattening fabrics defined largely by kinked and fractured mica grains. Adopting available kinetic models for the crystallization of I-S in burial sedimentary environments and the current borehole depths and thermal structure, the conditions and timing of I-S growth can be evaluated. Assuming a typical K+ concentration of 100-200 ppm for sedimentary brines, a present-day geothermal gradient of 35°C/km and a borehole temperature of ca. 112°C for the sampled depths, most of the I-S minerals can be predicted to have formed over the last 4-11 Ma and are probably still in equilibrium with circulating fluids. The exception to this simple burial pattern is the occurrence of the mixed layered phases with higher smectite content than predicted by the burial model. These minerals, which characterize the actively creeping section of the fault and local thin film

Influence of item distribution pattern and abundance on efficiency of benthic core sampling

USGS Publications Warehouse

Behney, Adam C.; O'Shaughnessy, Ryan; Eichholz, Michael W.; Stafford, Joshua D.

2014-01-01

ore sampling is a commonly used method to estimate benthic item density, but little information exists about factors influencing the accuracy and time-efficiency of this method. We simulated core sampling in a Geographic Information System framework by generating points (benthic items) and polygons (core samplers) to assess how sample size (number of core samples), core sampler size (cm2), distribution of benthic items, and item density affected the bias and precision of estimates of density, the detection probability of items, and the time-costs. When items were distributed randomly versus clumped, bias decreased and precision increased with increasing sample size and increased slightly with increasing core sampler size. Bias and precision were only affected by benthic item density at very low values (500–1,000 items/m2). Detection probability (the probability of capturing ≥ 1 item in a core sample if it is available for sampling) was substantially greater when items were distributed randomly as opposed to clumped. Taking more small diameter core samples was always more time-efficient than taking fewer large diameter samples. We are unable to present a single, optimal sample size, but provide information for researchers and managers to derive optimal sample sizes dependent on their research goals and environmental conditions.

Advanced Pressure Coring System for Deep Earth Sampling (APRECOS)

NASA Astrophysics Data System (ADS)

Anders, E.; Rothfuss, M.; Müller, W. H.

2009-04-01

Nowadays the recovery of cores from boreholes is a standard operation. However, during that process the mechanical, physical, and chemical properties as well as living conditions for microorganisms are significantly altered. In-situ sampling is one approach to overcome the severe scientific limitations of conventional, depressurized core investigations by recovering, processing, and conducting experiments in the laboratory, while maintaining unchanged environmental parameters. The most successful equipment today is the suite of tools developed within the EU funded projects HYACE (Hydrate Autoclave Coring Equipment) and HYACINTH (Deployment of HYACE tools In New Tests on Hydrates) between 1997 and 2005. Within several DFG (German Research Foundation) projects the Technical University Berlin currently works on concepts to increase the present working pressure of 250 bar as well as to reduce logistical and financial expenses by merging redundant and analogous procedures and scaling down the considerable size of key components. It is also proposed to extend the range of applications for the wireline rotary pressure corer and the sub-sampling and transfer system to all types of soil conditions (soft to highly-consolidated). New modifications enable the tools to be used in other pressure related fields of research, such as unconventional gas exploration (coal-bed methane, tight gas, gas hydrate), CO2 sequestration, and microbiology of the deep biosphere. Expedient enhancement of an overall solution for pressure core retrieval, process and investigation will open the way for a complete on-site, all-purpose, in-situ equipment. The advanced assembly would allow for executing the whole operation sequences of coring, non-destructive measurement, sub-sampling and transfer into storage, measurement and transportation chambers, all in sterile, anaerobic conditions, and without depressurisation in quick succession. Extensive post-cruise handling and interim storage would be

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

Optical Methods for Identifying Hard Clay Core Samples During Petrophysical Studies

NASA Astrophysics Data System (ADS)

Morev, A. V.; Solovyeva, A. V.; Morev, V. A.

2018-01-01

X-ray phase analysis of the general mineralogical composition of core samples from one of the West Siberian fields was performed. Electronic absorption spectra of the clay core samples with an added indicator were studied. The speed and availability of applying the two methods in petrophysical laboratories during sample preparation for standard and special studies were estimated.

Structural and Lithologic Characterization of the SAFOD Pilot Hole and Phase One Main Hole

NASA Astrophysics Data System (ADS)

Barton, D. C.; Bradbury, K.; Solum, J. G.; Evans, J. P.

2005-12-01

Petrological and microstructural analyses of drill cuttings were conducted for the San Andreas Fault Observatory at Depth (SAFOD) Pilot Hole and Main Hole projects. Grain mounts were produced at ~30 m (100 ft) intervals from drill cuttings collected from the Pilot Hole to a depth of 2164 m (7100 ft) and from Phase 1 of the SAFOD main hole to a depth of 3067 m (10062 ft). . Thin-section grain mount analysis included identification of mineral composition, alteration, and deformation within individual grains, measured at .5 mm increments on an equally spaced, 300 point grid pattern. Lithologic features in the Quaternary/Tertiary deposits from 30 - 640 m (100-2100 ft) in the Pilot Hole, and 670 - 792 m (2200 - 2600 ft) in the Phase 1 main hole, include fine-grained, thinly bedded sediments with clasts of fine-grained volcanic groundmass. Preliminary grain mount analysis from 1920 - 3067 m (6300 - 10062) in the Phase 1 main hole, indicates a sedimentary sequence consisting of fine-grained lithic fragments of very fine-grained shale. Deformation mechanisms observed within the cuttings of granitic rocks from 914 - 1860 m (3000 - 6100 ft.) include intracrystalline plasticity and cataclasis. Intracrystalline plastic deformation within quartz and feldspar grains is indicated by undulatory extinction, ribbon grains, chessboard patterns, and deformation twins and lamellae. Cataclastic deformation is characterized by intra- and intergranular microfractures, angular grains, gouge zones, iron-oxide banding, and comminution. Mineral and cataclasite abundances were plotted as a function of weight percent vs. depth. Plots of quartz and feldspar abundances are also correlated with XRD weight percent data from 1160 - 1890 m (3800 - 6200 ft.) in the granitic and granodioritic sequences of the Phase 1 main hole. Regions of the both of the drill holes with cataclasite abundances ranging from 20 - 30 wt% are interpreted as shear zones. Shear zones identified in this study from 1150 - 1420

A sample-freezing drive shoe for a wire line piston core sampler

USGS Publications Warehouse

Murphy, F.; Herkelrath, W.N.

1996-01-01

Loss of fluids and samples during retrieval of cores of saturated, noncohesive sediments results in incorrect measures of fluid distributions and an inaccurate measure of the stratigraphic position of the sample. To reduce these errors, we developed a hollow drive shoe that freezes in place the lowest 3 inches (75 mm) of a 1.88-inch-diameter (48 mm), 5-foot-long (1.5 m) sediment sample taken using a commercial wire line piston core sampler. The end of the core is frozen by piping liquid carbon dioxide at ambient temperature through a steel tube from a bottle at the land surface to the drive shoe where it evaporates and expands, cooling the interior surface of the shoe to about -109??F (-78??C). Freezing a core end takes about 10 minutes. The device was used to collect samples for a study of oil-water-air distributions, and for studies of water chemistry and microbial activity in unconsolidated sediments at the site of an oil spill near Bemidji, Minnesota. Before freezing was employed, samples of sandy sediments from near the water table sometimes flowed out of the core barrel as the sampler was withdrawn. Freezing the bottom of the core allowed for the retention of all material that entered the core barrel and lessened the redistribution of fluids within the core. The device is useful in the unsaturated and shallow saturated zones, but does not freeze cores well at depths greater than about 20 feet (6 m) below water, possibly because the feed tube plugs with dry ice with increased exhaust back-pressure, or because sediment enters the annulus between the core barrel and the core barrel liner and blocks the exhaust.

Baseline Design Compliance Matrix for the Rotary Mode Core Sampling System

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

LECHELT, J.A.

2000-10-17

The purpose of the design compliance matrix (DCM) is to provide a single-source document of all design requirements associated with the fifteen subsystems that make up the rotary mode core sampling (RMCS) system. It is intended to be the baseline requirement document for the RMCS system and to be used in governing all future design and design verification activities associated with it. This document is the DCM for the RMCS system used on Hanford single-shell radioactive waste storage tanks. This includes the Exhauster System, Rotary Mode Core Sample Trucks, Universal Sampling System, Diesel Generator System, Distribution Trailer, X-Ray Cart System,more » Breathing Air Compressor, Nitrogen Supply Trailer, Casks and Cask Truck, Service Trailer, Core Sampling Riser Equipment, Core Sampling Support Trucks, Foot Clamp, Ramps and Platforms and Purged Camera System. Excluded items are tools such as light plants and light stands. Other items such as the breather inlet filter are covered by a different design baseline. In this case, the inlet breather filter is covered by the Tank Farms Design Compliance Matrix.« less

Description and Analysis of Core Samples: The Lunar Experience

NASA Technical Reports Server (NTRS)

McKay, David S.; Allton, Judith H.

1997-01-01

Although no samples yet have been returned from a comet, extensive experience from sampling another solar system body, the Moon, does exist. While, in overall structure, composition, and physical properties the Moon bears little resemblance to what is expected for a comet, sampling the Moon has provided some basic lessons in how to do things which may be equally applicable to cometary samples. In particular, an extensive series of core samples has been taken on the Moon, and coring is the best way to sample a comet in three dimensions. Data from cores taken at 24 Apollo collection stations and 3 Luna sites have been used to provide insight into the evolution of the lunar regolith. It is now well understood that this regolith is very complex and reflects gardening (stirring of grains by micrometeorites), erosion (from impacts and solar wind sputtering), maturation (exposure on the bare lunar surface to solar winds ions and micrometeorite impacts) and comminution of coarse grains into finer grains, blanket deposition of coarse-grained layers, and other processes. All of these processes have been documented in cores. While a cometary regolith should not be expected to parallel in detail the lunar regolith, it is possible that the upper part of a cometary regolith may include textural, mineralogical, and chemical features which reflect the original accretion of the comet, including a form of gardening. Differences in relative velocities and gravitational attraction no doubt made this accretionary gardening qualitatively much different than the lunar version. Furthermore, at least some comets, depending on their orbits, have been subjected to impacts of the uppermost surface by small projectiles at some time in their history. Consequently, a more recent post-accretional gardening may have occurred. Finally, for comets which approach the sun, large scale erosion may have occurred driven by gas loss. The uppermost material of these comets may reflect some of the features

Quantitative x-ray diffraction mineralogy of Los Angeles basin core samples

USGS Publications Warehouse

Hein, James R.; McIntyre, Brandie R.; Edwards, Brian D.; Lakota, Orion I.

2006-01-01

This report contains X-ray diffraction (XRD) analysis of mineralogy for 81 sediment samples from cores taken from three drill holes in the Los Angeles Basin in 2000-2001. We analyzed 26 samples from Pier F core, 29 from Pier C core, and 26 from the Webster core. These three sites provide an offshore-onshore record across the Southern California coastal zone. This report is designed to be a data repository; these data will be used in further studies, including geochemical modeling as part of the CABRILLO project. Summary tables quantify the major mineral groups, whereas detailed mineralogy is presented in three appendices. The rationale, methodology, and techniques are described in the following paper.

Deep rock damage in the San Andreas Fault revealed by P- and S-type fault-zone-guided waves

USGS Publications Warehouse

Ellsworth, William L.; Malin, Peter E.

2011-01-01

Damage to fault-zone rocks during fault slip results in the formation of a channel of low seismic-wave velocities. Within such channels guided seismic waves, denoted by Fg, can propagate. Here we show with core samples, well logs and Fg-waves that such a channel is crossed by the SAFOD (San Andreas Fault Observatory at Depth) borehole at a depth of 2.7 km near Parkfield, California, USA. This laterally extensive channel extends downwards to at least half way through the seismogenic crust, more than about 7 km. The channel supports not only the previously recognized Love-type- (FL) and Rayleigh-type- (FR) guided waves, but also a new fault-guided wave, which we name FF. As recorded 2.7 km underground, FF is normally dispersed, ends in an Airy phase, and arrives between the P- and S-waves. Modelling shows that FF travels as a leaky mode within the core of the fault zone. Combined with the drill core samples, well logs and the two other types of guided waves, FF at SAFOD reveals a zone of profound, deep, rock damage. Originating from damage accumulated over the recent history of fault movement, we suggest it is maintained either by fracturing near the slip surface of earthquakes, such as the 1857 Fort Tejon M 7.9, or is an unexplained part of the fault-creep process known to be active at this site.

Water column and bed-sediment core samples collected from Brownlee Reservoir near Oxbow, Oregon, 2012

USGS Publications Warehouse

Fosness, Ryan L.; Naymik, Jesse; Hopkins, Candice B.; DeWild, John F.

2013-01-01

The U.S. Geological Survey, in cooperation with Idaho Power Company, collected water-column and bed-sediment core samples from eight sites in Brownlee Reservoir near Oxbow, Oregon, during May 5–7, 2012. Water-column and bed-sediment core samples were collected at each of the eight sites and analyzed for total mercury and methylmercury. Additional bed-sediment core samples, collected from three of the eight sites, were analyzed for pesticides and other organic compounds, trace metals, and physical characteristics, such as particle size. Total mercury and methylmercury were detected in each of the water column and bed-sediment core samples. Only 17 of the 417 unique pesticide and organic compounds were detected in bed-sediment core samples. Concentrations of most organic wastewater compounds detected in bed sediment were less than the reporting level. Trace metals detected were greater than the reporting level in all the bed-sediment core samples submitted for analysis. The particle size distribution of bed-sediment core samples was predominantly clay mixed with silt.

Full wave field recording of the vertical strain at SAFOD from local, regional and teleseismic earthquakes

NASA Astrophysics Data System (ADS)

Ellsworth, W. L.; Karrenbach, M. H.; Zumberge, M. A.

2017-12-01

The main borehole at the San Andreas Fault Observatory at Depth (SAFOD) contains optical fibers cemented in place in between casing strings from the surface to just below the top of the basement. The fibers are under tension of approximately 1 N and are housed in a 0.9 mm diameter stainless steel tube. Earth strain is transmitted to the fiber by frictional contact with the tube wall. One fiber has been in use as a vertical strainmeter since 2005, measuring the total strain between 9 and 740 m by laser interferometry. In June 2017 we attached an OptaSense Distributed Acoustic Sensing (DAS) system, model ODH3.1, to a second fiber that terminates at 864 m depth. The DAS laser interrogator measures the strain over a gauge length with a set spacing between gauge intervals. For this experiment we set the gauge length to 10 m with 1 m spacing between gauges. Including the surface run of the fiber, this gives us 936 channels measuring the vertical strain at a sample interval of 0.4 msec (2500 samples/s). Continuous recording of the string produces approximately 1 TB/day. During one month of data collection, we recorded local, regional and teleseismic earthquakes. With this recording geometry, the DAS system captures the full vertical wavefield between the basement interface and free surface, revealing direct, converted and refracted waves. Both P- and S- strain waves are clearly visible in the data, even for 10 km deep earthquakes located almost directly below the well (see figure). The incident and surface reflected wavefields can be separated by frequency-wavenumber filtering due to the large-aperture and fine spatial and temporal sampling. Up- and downgoing strain waves illuminate the subsurface within the sensor array's depth range. Accurate arrival time determinations of the initial arrival phase are possible due to consistent wave forms recorded at 1 m spatial intervals that can be used for fine-scale shallow velocity model estimation.

Effects of core retrieval, handling, and preservation on hydrate-bearing samples

NASA Astrophysics Data System (ADS)

Kneafsey, T. J.; Lu, H.; Winters, W. J.; Hunter, R. B.

2009-12-01

Recovery, preservation, storage, and transport of samples containing natural gas hydrate cause changes in the stress conditions, temperature, pressure, and hydrate saturation of samples. Sample handling at the ground surface and sample preservation, either by freezing in liquid nitrogen (LN) or repressurization using methane, provides additional time and driving forces for sample alteration. The extent to which these disturbances alter the properties of the hydrate bearing sediments (HBS) depend on specific sample handling techniques, as well as on the sample itself. HBS recovered during India’s National Gas Hydrate Program (NGHP) Expedition 01 and the 2007 BP Exploration Alaska - Department of Energy - U.S. Geological Survey (BP-DOE-USGS) Mount Elbert (ME) gas hydrate well on the Alaskan North Slope provide comparisons of sample alterations induced by multiple handling techniques. HBS samples from the NGHP and the ME projects were examined using x-ray computed tomography. Mount Elbert sand samples initially preserved in LN have non-uniform short “crack-like” low-density zones in the center that probably do not extend to the outside perimeter. Samples initially preserved by repressurization show fewer “crack-like” features and higher densities. Two samples were analyzed in detail by Lu and coworkers showing reduced hydrate saturations approaching the outer surface, while substantial hydrate remained in the central region. Non-pressure cored NGHP samples show relatively large altered regions approaching the core surface, while pressure-cored-liquid-nitrogen preserved samples have much less alteration.

A Xhosa language translation of the CORE-OM using South African university student samples.

PubMed

Campbell, Megan M; Young, Charles

2016-10-01

The translation of well established psychometric tools from English into Xhosa may assist in improving access to psychological services for Xhosa speakers. The aim of this study was to translate the Clinical Outcomes in Routine Evaluation - Outcome Measure (CORE-OM), a measure of general distress and dysfunction developed in the UK, into Xhosa for use at South African university student counselling centres. The CORE-OM and embedded CORE-10 were translated into Xhosa using a five-stage translation design. This design included (a) forward-translation, (b) back-translation, (c) committee approach, (d) qualitative piloting, and (e) quantitative piloting on South African university students. Clinical and general samples were drawn from English-medium South African universities. Clinical samples were generated from university student counselling centres. General student samples were generated through random stratified cluster sampling of full-time university students. Qualitative feedback from the translation process and results from quantitative piloting of the 34-item CORE-OM English and Xhosa versions supported the reduction of the scale to 10 items. This reduced scale is referred to as the South African CORE-10 (SA CORE-10). A measurement and structural model of the SA CORE-10 English version was developed and cross-validated using an English-speaking university student sample. Equivalence of this model with the SA CORE-10 Xhosa version was investigated using a first-language Xhosa-speaking university sample. Partial measurement equivalence was achieved at the metric level. The resultant SA CORE-10 Xhosa and English versions provide core measures of distress and dysfunction. Additional, culture- and language-specific domains could be added to increase sensitivity and specificity. © The Author(s) 2016.

The CoreWall Project: An Update for 2007

NASA Astrophysics Data System (ADS)

Yu-Chung Chen, J.; Higgins, S.; Hur, H.; Ito, E.; Jenkins, C. J.; Johnson, A.; Leigh, J.; Morin, P.; Lee, J.

2007-12-01

The CoreWall Suite is a NSF-supported collaborative development for a real-time core description (Corelyzer), stratigraphic correlation (Correlater), and data visualization (CoreNavigator) software to be used by the marine, terrestrial and Antarctic science communities. The overall goal of the Corewall software development is to bring portable cross-platform tools to the broader drilling and coring communities to expand and enhance data visualization and enhance collaborative integration of multiple datasets. The CoreWall Project is now in its second year and significant progress has been made on all 3 software components. Corelyzer has undergone 2 field deployments and testing by ANDRILL program in 2006 (and again in Fall 2007) and by ICDP's SAFOD project (summer 2007). In addition, Corewall group and ICDP are working together so that the core description (DIS) system can expose DIS core data directly into Corelyzer seamlessly and be available to future ICDP and IODP-Mission Specific Platform expeditions. Educators have also taken note of the software's ease of use and strong visualization capabilities to begin exploring curriculum projects with Corelyzer software. To ensure that the software development is integrated with other community IT activities the development of the U.S. IODP-Phase 2 Scientific Ocean Drilling Vessel (SODV), a Steering Committee was constituted. It is composed of key U.S. IODP and related database (e.g., CHRONOS, SedDB) developers and users as well as representatives of other core-based enterprises (e.g., ANDRILL, ICDP, LacCore). Corelyzer (CoreWall's main visual core description tool) software displays digital core images from one or more cores along with discrete data streams (eg. physical properties, downhole logs) and nested images (eg. thin sections, fossils) to provide a robust approach to the description of sediment cores. Corelyzer's digital image handling allows the cores to be viewed from micron to km scale determined by the

Geotechnical properties of core sample from methane hydrate deposits in Eastern Nankai Trough

NASA Astrophysics Data System (ADS)

Yoneda, J.; Masui, A.; Egawa, K.; Konno, Y.; Ito, T.; Kida, M.; Jin, Y.; Suzuki, K.; Nakatsuka, Y.; Tenma, N.; Nagao, J.

2013-12-01

To date, MH extraction has been simulated in several ways to help ensure the safe and efficient production of gas, with a particular focus on the investigation of landsliding, uneven settlement, and production well integrity. The mechanical properties of deep sea sediments and gas-hydrate-bearing sediments, typically obtained through material tests, are essential for the geomechanical response simulation to hydrate extraction. We conducted triaxial compression tests and the geotechnical properties of the sediments was investigated. Consolidated undrained compression tests were performed for silty sediments. And consolidated drained tests were performed for sandy samples. In addition, permeability was investigated from isotropic consolidation results. These core samples recovered from methane hydrate deposits of Daini Atsumi Knoll in Eastern Nankai Trough during the 2012 JOGMEC/JAPEX Pressure coring operation. The pressure core samples were rapidly depressurized on the ship and it were frozen using liquid nitrogen to prevent MH dissociation. Undrained shear strength of the core samples increase linearly with depth from sea floor. These core samples should be normally consolidated sample in-situ. Drained shear strength increases dramatically with hydrate saturation increases. Peak stress ratio q/p' of the core sample which has 73% of hydrate saturation was approximately 2.0 and it decrease down to 1.3 at the critical state. Dilatancy also changed from compressive tendency to dilative tendency with hydrate saturation increase. This study was financially supported by the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) that carries out Japan's Methane Hydrate R&D Program conducted by the Ministry of Economy, Trade and Industry (METI).

A high-throughput core sampling device for the evaluation of maize stalk composition

PubMed Central

2012-01-01

Background A major challenge in the identification and development of superior feedstocks for the production of second generation biofuels is the rapid assessment of biomass composition in a large number of samples. Currently, highly accurate and precise robotic analysis systems are available for the evaluation of biomass composition, on a large number of samples, with a variety of pretreatments. However, the lack of an inexpensive and high-throughput process for large scale sampling of biomass resources is still an important limiting factor. Our goal was to develop a simple mechanical maize stalk core sampling device that can be utilized to collect uniform samples of a dimension compatible with robotic processing and analysis, while allowing the collection of hundreds to thousands of samples per day. Results We have developed a core sampling device (CSD) to collect maize stalk samples compatible with robotic processing and analysis. The CSD facilitates the collection of thousands of uniform tissue cores consistent with high-throughput analysis required for breeding, genetics, and production studies. With a single CSD operated by one person with minimal training, more than 1,000 biomass samples were obtained in an eight-hour period. One of the main advantages of using cores is the high level of homogeneity of the samples obtained and the minimal opportunity for sample contamination. In addition, the samples obtained with the CSD can be placed directly into a bath of ice, dry ice, or liquid nitrogen maintaining the composition of the biomass sample for relatively long periods of time. Conclusions The CSD has been demonstrated to successfully produce homogeneous stalk core samples in a repeatable manner with a throughput substantially superior to the currently available sampling methods. Given the variety of maize developmental stages and the diversity of stalk diameter evaluated, it is expected that the CSD will have utility for other bioenergy crops as well. PMID

Comparative mineral chemistry and textures of SAFOD fault gouge and damage-zone rocks

USGS Publications Warehouse

Moore, Diane E.

2014-01-01

Creep in the San Andreas Fault Observatory at Depth (SAFOD) drillhole is localized to two foliated gouges, the central deforming zone (CDZ) and southwest deforming zone (SDZ). The gouges consist of porphyroclasts of serpentinite and sedimentary rock dispersed in a foliated matrix of Mg-smectite clays that formed as a result of shearing-enhanced reactions between the serpentinite and quartzofeldspathic rocks. The CDZ takes up most of the creep and exhibits differences in mineralogy and texture from the SDZ that are attributable to its higher shearing rate. In addition, a ∼0.2-m-wide sector of the CDZ at its northeastern margin (NE-CDZ) is identical to the SDZ and may represent a gradient in creep rate across the CDZ. The SDZ and NE-CDZ have lower clay contents and larger porphyroclasts than most of the CDZ, and they contain veinlets and strain fringes of calcite in the gouge matrix not seen elsewhere in the CDZ. Matrix clays in the SDZ and NE-CDZ are saponite and corrensite, whereas the rest of the CDZ lacks corrensite. Saponite is younger than corrensite, reflecting clay crystallization under declining temperatures, and clays in the more actively deforming portions of the CDZ have better equilibrated to the lower-temperature conditions.

System Would Acquire Core and Powder Samples of Rocks

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Randolph, James; Bao, Xiaoqi; Sherrit, Stewart; Ritz, Chuck; Cook, Greg

2006-01-01

A system for automated sampling of rocks, ice, and similar hard materials at and immediately below the surface of the ground is undergoing development. The system, denoted a sample preparation, acquisition, handling, and delivery (SPAHD) device, would be mounted on a robotic exploratory vehicle that would traverse the terrain of interest on the Earth or on a remote planet. The SPAHD device would probe the ground to obtain data for optimization of sampling, prepare the surface, acquire samples in the form(s) of cores and/or powdered cuttings, and deliver the samples to a selected location for analysis and/or storage.

Characteristics of hydrocarbons in sediment core samples from the northern Okinawa Trough.

PubMed

Huang, Xin; Chen, Shuai; Zeng, Zhigang; Pu, Xiaoqiang; Hou, Qinghua

2017-02-15

Sediment core samples from the northern Okinawa Trough (OT) were analyzed to determine abundances and distributions of hydrocarbons by gas chromatography-mass spectrometer (GC-MS). The results show that the n-alkanes in this sediment core conform to a bimodal distribution, and exhibit an odd-to-even predominance of high molecular weights compared to an even-to-odd predominance in low molecular weight n-alkanes with maxima at C 16 and C 18 . The concentrations of bitumen, alkanes and polyaromatic hydrocarbons (PAHs) were higher in samples S10-07 than all others. Three maturity parameters as well as the ratios between parent phenanthrenes (Ps) and methylphenanthrenes (MPs) in samples S10-07 and S10-17 were higher. The distribution and composition of hydrocarbons in sample S10-07 suggest that one, or several, undetected hydrothermal fields may be present in the region of this sediment core. Results also suggest that volcanism may be the main reason for the observed distribution and composition of hydrocarbons in S10-17 sample. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mars Technology Rover with Arm-Mounted Percussive Coring Tool, Microimager, and Sample-Handling Encapsulation Containerization Subsystem

NASA Technical Reports Server (NTRS)

Younse, Paulo J.; Dicicco, Matthew A.; Morgan, Albert R.

2012-01-01

A report describes the PLuto (programmable logic) Mars Technology Rover, a mid-sized FIDO (field integrated design and operations) class rover with six fully drivable and steerable cleated wheels, a rocker-bogey suspension, a pan-tilt mast with panorama and navigation stereo camera pairs, forward and rear stereo hazcam pairs, internal avionics with motor drivers and CPU, and a 5-degrees-of-freedom robotic arm. The technology rover was integrated with an arm-mounted percussive coring tool, microimager, and sample handling encapsulation containerization subsystem (SHEC). The turret of the arm contains a percussive coring drill and microimager. The SHEC sample caching system mounted to the rover body contains coring bits, sample tubes, and sample plugs. The coring activities performed in the field provide valuable data on drilling conditions for NASA tasks developing and studying coring technology. Caching of samples using the SHEC system provide insight to NASA tasks investigating techniques to store core samples in the future.

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

Earthquake source parameters of repeating microearthquakes at Parkfield, CA, determined using the SAFOD Pilot Hole seismic array

NASA Astrophysics Data System (ADS)

Imanishi, K.; Ellsworth, W. L.

2005-12-01

We determined source parameters of repeating microearthquakes occurring at Parkfield, CA, using the SAFOD Pilot Hole seismic array. To estimate reliable source parameters, we used the empirical Green's function (EGF) deconvolution method which removes the attenuation effects and site responses by taking the spectral amplitude ratio between the spectra of the two colocated events. For earthquakes during the period from December 2002 to October 2003 whose S-P time differences are less than 1 s, we detected 34 events that classified into 14 groups. Moment magnitudes range from -0.3 to 2.1. These data were recorded at a sampling rate of 2 kHz. The dataset includes two SAFOD target repeating earthquakes which occurred on October 2003. In general, the deconvolution procedure is an unstable process, especially for higher frequencies, because small location differences result in the profound effects on the spectral ratio. This leads to large uncertainties in the estimations of corner frequencies. According to Chaverria et al. [2003], the wavetrain recorded in the Pilot Hole is dominated by reflections and conversions and not random coda waves. So, we expect that the spectral ratios of the waves between P and S wave will also reflect the source, as will the waves following S wave. We compared spectral ratios calculated from the direct waves with those from other parts of the wavetrain, and confirmed that they showed similar shapes. Therefore it is possible to obtain a more robust measure of spectral ratio by stacking the ratios calculated from shorter moving windows taken along the record following the direct waves. We further stacked all ratios obtained from each level of the array. The stacked spectral ratios were inverted for corner frequencies assuming the omega-square model. We determined static stress drops from those corner frequencies assuming a circular crack model. We also calculated apparent stresses for each event by considering frequency dependent attenuation

Determination of the neutron activation profile of core drill samples by gamma-ray spectrometry.

PubMed

Gurau, D; Boden, S; Sima, O; Stanga, D

2018-04-01

This paper provides guidance for determining the neutron activation profile of core drill samples taken from the biological shield of nuclear reactors using gamma spectrometry measurements. Thus, it provides guidance for selecting a model of the right form to fit data and using least squares methods for model fitting. The activity profiles of two core samples taken from the biological shield of a nuclear reactor were determined. The effective activation depth and the total activity of core samples along with their uncertainties were computed by Monte Carlo simulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stabilization of lunar core samples

NASA Technical Reports Server (NTRS)

Nagle, J. S.; Duke, M. B.

1974-01-01

Processing of lunar cores includes: (1) careful dissection for study of loose fines, and (2) stabilization of the residue by peeling and impregnation. The newly developed technique for preparing thin peels of lunar cores requires application of the methacrylate adhesive to a backing strip, before taking the peel. To ensure complete impregnation of the very fine, dry lunar soil, the low-viscosity epoxy, Araldite 506, is gently flowed onto the core, under vacuum.

A wireline piston core barrel for sampling cohesionless sand and gravel below the water table

USGS Publications Warehouse

Zapico, Michael M.; Vales, Samuel; Cherry, John A.

1987-01-01

A coring device has been developed to obtain long and minimally disturbed samples of saturated cohesionless sand and gravel. The coring device, which includes a wireline and piston, was developed specifically for use during hollow-stem auger drilling but it also offers possibilities for cable tool and rotary drilling. The core barrel consists of an inner liner made of inexpensive aluminum or plastic tubing, a piston for core recovery, and an exterior steel housing that protects the liner when the core barrel is driven into the aquifer. The core barrel, which is approximately 1.6m (5.6 feet) long, is advanced ahead of the lead auger by hammering at the surface on drill rods that are attached to the core barrel. After the sampler has been driven 1.5m (5 feet), the drill rods are detached and a wireline is used to hoist the core barrel, with the sample contained in the aluminum or plastic liner, to the surface. A vacuum developed by the piston during the coring operation provides good recovery of both the sediment and aquifer fluids contained in the sediment. In the field the sample tubes can be easily split along their length for on-site inspection or they can be capped with the pore water fluids inside and transported to the laboratory. The cores are 5cm (2 inches) in diameter by 1.5m (5 feet) long. Core acquisition to depths of 35m (115 feet), with a recovery greater than 90 percent, has become routine in University of Waterloo aquifer studies. A large diameter (12.7cm [5 inch]) version has also been used successfully. Nearly continuous sample sequences from sand and gravel aquifers have been obtained for studies of sedimentology, hydraulic conductivity, hydrogeochemistry and microbiology.

Contamination assessment in microbiological sampling of the Eyreville core, Chesapeake Bay impact structure

USGS Publications Warehouse

Gronstal, A.L.; Voytek, M.A.; Kirshtein, J.D.; Von der, Heyde; Lowit, M.D.; Cockell, C.S.

2009-01-01

Knowledge of the deep subsurface biosphere is limited due to difficulties in recovering materials. Deep drilling projects provide access to the subsurface; however, contamination introduced during drilling poses a major obstacle in obtaining clean samples. To monitor contamination during the 2005 International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) deep drilling of the Chesapeake Bay impact structure, four methods were utilized. Fluorescent microspheres were used to mimic the ability of contaminant cells to enter samples through fractures in the core material during retrieval. Drilling mud was infused with a chemical tracer (Halon 1211) in order to monitor penetration of mud into cores. Pore water from samples was examined using excitation-emission matrix (EEM) fl uorescence spectroscopy to characterize dissolved organic carbon (DOC) present at various depths. DOC signatures at depth were compared to signatures from drilling mud in order to identify potential contamination. Finally, microbial contaminants present in drilling mud were identified through 16S ribosomal deoxyribonucleic acid (rDNA) clone libraries and compared to species cultured from core samples. Together, these methods allowed us to categorize the recovered core samples according to the likelihood of contamination. Twenty-two of the 47 subcores that were retrieved were free of contamination by all the methods used and were subsequently used for microbiological culture and culture-independent analysis. Our approach provides a comprehensive assessment of both particulate and dissolved contaminants that could be applied to any environment with low biomass. ?? 2009 The Geological Society of America.

Core vs. Bulk Samples in Soil-Moisture Tension Analyses

Treesearch

Walter M. Broadfoot

1954-01-01

The usual laboratory procedure in determining soil-moisture tension values is to use "undisturbed" soil cores for tensions up to 60 cm. of water and bulk soil samples for higher tensions. Low tensions are usually obtained with a tension table and the higher tensions by use of pressure plate apparatus. In tension analysis at the Vicksburg Infiltration Project...

Application of drilling, coring, and sampling techniques to test holes and wells

USGS Publications Warehouse

Shuter, Eugene; Teasdale, Warren E.

1989-01-01

The purpose of this manual is to provide ground-water hydrologists with a working knowledge of the techniques of test drilling, auger drilling, coring and sampling, and the related drilling and sampling equipment. For the most part, the techniques discussed deal with drilling, sampling, and completion of test holes in unconsolidated sediments because a hydrologist is interested primarily in shallow-aquifer data in this type of lithology. Successful drilling and coring of these materials usually is difficult, and published research information on the subject is not readily available. The authors emphasize in-situ sampling of unconsolidated sediments to obtain virtually undisturbed samples. Particular attention is given to auger drilling and hydraulic-rotary methods of drilling because these are the principal means of test drilling performed by the U.S. Geological Survey during hydrologic studies. Techniques for sampling areas contaminated by solid or liquid waste are discussed. Basic concepts of well development and a detailed discussion of drilling muds, as related to hole conditioning, also are included in the report. The information contained in this manual is intended to help ground-water hydrologists obtain useful subsurface data and samples from their drilling programs.

Portable tester for determining gas content within a core sample

DOEpatents

Garcia, Jr., Fred; Schatzel, Steven J.

1998-01-01

A portable tester is provided for reading and displaying the pressure of a gas released from a rock core sample stored within a sealed container and for taking a sample of the released pressurized gas for chemical analysis thereof for subsequent use in a modified direct method test which determines the volume of gas and specific type of gas contained within the core sample. The portable tester includes a pair of low and high range electrical pressure transducers for detecting a gas pressure; a pair of low and high range display units for displaying the pressure of the detected gas- a selector valve connected to the low and high range pressure transducers, a selector knob for selecting gas flow to one of the flow paths; control valve having an inlet connection to the sealed container, and outlets connected to: a sample gas canister, a second outlet port connected to the selector valve means for reading the pressure of the gas from the sealed container to either the low range or high range pressure transducers, and a connection for venting gas contained within the sealed container to the atmosphere. A battery is electrically connected to and supplies the power for operating the unit. The pressure transducers, display units, selector and control valve means and the battery is mounted to and housed within a protective casing for portable transport and use.

Acquisition and Retaining Granular Samples via a Rotating Coring Bit

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Badescu, Mircea; Sherrit, Stewart

2013-01-01

This device takes advantage of the centrifugal forces that are generated when a coring bit is rotated, and a granular sample is entered into the bit while it is spinning, making it adhere to the internal wall of the bit, where it compacts itself into the wall of the bit. The bit can be specially designed to increase the effectiveness of regolith capturing while turning and penetrating the subsurface. The bit teeth can be oriented such that they direct the regolith toward the bit axis during the rotation of the bit. The bit can be designed with an internal flute that directs the regolith upward inside the bit. The use of both the teeth and flute can be implemented in the same bit. The bit can also be designed with an internal spiral into which the various particles wedge. In another implementation, the bit can be designed to collect regolith primarily from a specific depth. For that implementation, the bit can be designed such that when turning one way, the teeth guide the regolith outward of the bit and when turning in the opposite direction, the teeth will guide the regolith inward into the bit internal section. This mechanism can be implemented with or without an internal flute. The device is based on the use of a spinning coring bit (hollow interior) as a means of retaining granular sample, and the acquisition is done by inserting the bit into the subsurface of a regolith, soil, or powder. To demonstrate the concept, a commercial drill and a coring bit were used. The bit was turned and inserted into the soil that was contained in a bucket. While spinning the bit (at speeds of 600 to 700 RPM), the drill was lifted and the soil was retained inside the bit. To prove this point, the drill was turned horizontally, and the acquired soil was still inside the bit. The basic theory behind the process of retaining unconsolidated mass that can be acquired by the centrifugal forces of the bit is determined by noting that in order to stay inside the interior of the bit, the

Portable tester for determining gas content within a core sample

DOEpatents

Garcia, F. Jr.; Schatzel, S.J.

1998-04-21

A portable tester is provided for reading and displaying the pressure of a gas released from a rock core sample stored within a sealed container and for taking a sample of the released pressurized gas for chemical analysis thereof for subsequent use in a modified direct method test which determines the volume of gas and specific type of gas contained within the core sample. The portable tester includes a pair of low and high range electrical pressure transducers for detecting a gas pressure; a pair of low and high range display units for displaying the pressure of the detected gas; a selector valve connected to the low and high range pressure transducers and a selector knob for selecting gas flow to one of the flow paths; control valve having an inlet connection to the sealed container; and outlets connected to: a sample gas canister, a second outlet port connected to the selector valve means for reading the pressure of the gas from the sealed container to either the low range or high range pressure transducers, and a connection for venting gas contained within the sealed container to the atmosphere. A battery is electrically connected to and supplies the power for operating the unit. The pressure transducers, display units, selector and control valve means and the battery is mounted to and housed within a protective casing for portable transport and use. 5 figs.

Oil-shale data, cores, and samples collected by the U.S. geological survey through 1989

USGS Publications Warehouse

Dyni, John R.; Gay, Frances; Michalski, Thomas C.; ,

1990-01-01

The U.S. Geological Survey has acquired a large collection of geotechnical data, drill cores, and crushed samples of oil shale from the Eocene Green River Formation in Colorado, Wyoming, and Utah. The data include about 250,000 shale-oil analyses from about 600 core holes. Most of the data is from Colorado where the thickest and highest-grade oil shales of the Green River Formation are found in the Piceance Creek basin. Other data on file but not yet in the computer database include hundreds of lithologic core descriptions, geophysical well logs, and mineralogical and geochemical analyses. The shale-oil analyses are being prepared for release on floppy disks for use on microcomputers. About 173,000 lineal feet of drill core of oil shale and associated rocks, as well as 100,000 crushed samples of oil shale, are stored at the Core Research Center, U.S. Geological Survey, Lakewood, Colo. These materials are available to the public for research.

Freeze core sampling to validate time-lapse resistivity monitoring of the hyporheic zone.

PubMed

Toran, Laura; Hughes, Brian; Nyquist, Jonathan; Ryan, Robert

2013-01-01

A freeze core sampler was used to characterize hyporheic zone storage during a stream tracer test. The pore water from the frozen core showed tracer lingered in the hyporheic zone after the tracer had returned to background concentration in collocated well samples. These results confirmed evidence of lingering subsurface tracer seen in time-lapse electrical resistivity tomographs. The pore water exhibited brine exclusion (ion concentrations in ice lower than source water) in a sediment matrix, despite the fast freezing time. Although freeze core sampling provided qualitative evidence of lingering tracer, it proved difficult to quantify tracer concentration because the amount of brine exclusion during freezing could not be accurately determined. Nonetheless, the additional evidence for lingering tracer supports using time-lapse resistivity to detect regions of low fluid mobility within the hyporheic zone that can act as chemically reactive zones of importance in stream health. © 2012, The Author(s). GroundWater © 2012, National Ground Water Association.

Examination of core samples from the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Effects of retrieval and preservation

USGS Publications Warehouse

Kneafsey, T.J.; Lu, H.; Winters, W.; Boswell, R.; Hunter, R.; Collett, T.S.

2011-01-01

Collecting and preserving undamaged core samples containing gas hydrates from depth is difficult because of the pressure and temperature changes encountered upon retrieval. Hydrate-bearing core samples were collected at the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well in February 2007. Coring was performed while using a custom oil-based drilling mud, and the cores were retrieved by a wireline. The samples were characterized and subsampled at the surface under ambient winter arctic conditions. Samples thought to be hydrate bearing were preserved either by immersion in liquid nitrogen (LN), or by storage under methane pressure at ambient arctic conditions, and later depressurized and immersed in LN. Eleven core samples from hydrate-bearing zones were scanned using x-ray computed tomography to examine core structure and homogeneity. Features observed include radial fractures, spalling-type fractures, and reduced density near the periphery. These features were induced during sample collection, handling, and preservation. Isotopic analysis of the methane from hydrate in an initially LN-preserved core and a pressure-preserved core indicate that secondary hydrate formation occurred throughout the pressurized core, whereas none occurred in the LN-preserved core, however no hydrate was found near the periphery of the LN-preserved core. To replicate some aspects of the preservation methods, natural and laboratory-made saturated porous media samples were frozen in a variety of ways, with radial fractures observed in some LN-frozen sands, and needle-like ice crystals forming in slowly frozen clay-rich sediments. Suggestions for hydrate-bearing core preservation are presented.

A Review of Inflammatory Processes of the Breast with a Focus on Diagnosis in Core Biopsy Samples

PubMed Central

D’Alfonso, Timothy M.; Ginter, Paula S.; Shin, Sandra J.

2015-01-01

Inflammatory and reactive lesions of the breast are relatively uncommon among benign breast lesions and can be the source of an abnormality on imaging. Such lesions can simulate a malignant process, based on both clinical and radiographic findings, and core biopsy is often performed to rule out malignancy. Furthermore, some inflammatory processes can mimic carcinoma or other malignancy microscopically, and vice versa. Diagnostic difficulty may arise due to the small and fragmented sample of a core biopsy. This review will focus on the pertinent clinical, radiographic, and histopathologic features of the more commonly encountered inflammatory lesions of the breast that can be characterized in a core biopsy sample. These include fat necrosis, mammary duct ectasia, granulomatous lobular mastitis, diabetic mastopathy, and abscess. The microscopic differential diagnoses for these lesions when seen in a core biopsy sample will be discussed. PMID:26095437

A Review of Inflammatory Processes of the Breast with a Focus on Diagnosis in Core Biopsy Samples.

PubMed

D'Alfonso, Timothy M; Ginter, Paula S; Shin, Sandra J

2015-07-01

Inflammatory and reactive lesions of the breast are relatively uncommon among benign breast lesions and can be the source of an abnormality on imaging. Such lesions can simulate a malignant process, based on both clinical and radiographic findings, and core biopsy is often performed to rule out malignancy. Furthermore, some inflammatory processes can mimic carcinoma or other malignancy microscopically, and vice versa. Diagnostic difficulty may arise due to the small and fragmented sample of a core biopsy. This review will focus on the pertinent clinical, radiographic, and histopathologic features of the more commonly encountered inflammatory lesions of the breast that can be characterized in a core biopsy sample. These include fat necrosis, mammary duct ectasia, granulomatous lobular mastitis, diabetic mastopathy, and abscess. The microscopic differential diagnoses for these lesions when seen in a core biopsy sample will be discussed.

A distance-limited sample of massive star-forming cores from the RMS

NASA Astrophysics Data System (ADS)

Maud, L. T.; Lumsden, S. L.; Moore, T. J. T.; Mottram, J. C.; Urquhart, J. S.; Cicchini, A.

2015-09-01

We analyse C18O (J = 3-2) data from a sample of 99 infrared (IR)-bright massive young stellar objects (MYSOs) and compact H II regions that were identified as potential molecular-outflow sources in the Red MSX Source survey. We extract a distance-limited (D < 6 kpc) sample shown to be representative of star formation covering the transition between the source types. At the spatial resolution probed, Larson-like relationships are found for these cores, though the alternative explanation, that Larson's relations arise where surface-density-limited samples are considered, is also consistent with our data. There are no significant differences found between source properties for the MYSOs and H II regions, suggesting that the core properties are established prior to the formation of massive stars, which subsequently have little impact at the later evolutionary stages investigated. There is a strong correlation between dust-continuum and C18O-gas masses, supporting the interpretation that both trace the same material in these IR-bright sources. A clear linear relationship is seen between the independently established core masses and luminosities. The position of MYSOs and compact H II regions in the mass-luminosity plane is consistent with the luminosity expected from the most massive protostar in the cluster when using an ˜40 per cent star formation efficiency and indicates that they are at a similar evolutionary stage, near the end of the accretion phase.

Water isotopic ratios from a continuously melted ice core sample

NASA Astrophysics Data System (ADS)

Gkinis, V.; Popp, T. J.; Blunier, T.; Bigler, M.; Schüpbach, S.; Johnsen, S. J.

2011-06-01

A new technique for on-line high resolution isotopic analysis of liquid water, tailored for ice core studies is presented. We build an interface between an Infra Red Cavity Ring Down Spectrometer (IR-CRDS) and a Continuous Flow Analysis (CFA) system. The system offers the possibility to perform simultaneuous water isotopic analysis of δ18O and δD on a continuous stream of liquid water as generated from a continuously melted ice rod. Injection of sub μl amounts of liquid water is achieved by pumping sample through a fused silica capillary and instantaneously vaporizing it with 100 % efficiency in a home made oven at a temperature of 170 °C. A calibration procedure allows for proper reporting of the data on the VSMOW scale. We apply the necessary corrections based on the assessed performance of the system regarding instrumental drifts and dependance on humidity levels. The melt rates are monitored in order to assign a depth scale to the measured isotopic profiles. Application of spectral methods yields the combined uncertainty of the system at below 0.1 ‰ and 0.5 ‰ for δ18O and δD, respectively. This performance is comparable to that achieved with mass spectrometry. Dispersion of the sample in the transfer lines limits the resolution of the technique. In this work we investigate and assess these dispersion effects. By using an optimal filtering method we show how the measured profiles can be corrected for the smoothing effects resulting from the sample dispersion. Considering the significant advantages the technique offers, i.e. simultaneuous measurement of δ18O and δD, potentially in combination with chemical components that are traditionally measured on CFA systems, notable reduction on analysis time and power consumption, we consider it as an alternative to traditional isotope ratio mass spectrometry with the possibility to be deployed for field ice core studies. We present data acquired in the framework of the NEEM deep ice core drilling project in

Benthic foraminiferal census data from Mobile Bay, Alabama--counts of surface samples and box cores

USGS Publications Warehouse

Richwine, Kathryn A.; Osterman, Lisa E.

2012-01-01

A study was undertaken in order to understand recent environmental change in Mobile Bay, Alabama. For this study a series of surface sediment and box core samples was collected. The surface benthic foraminiferal data provide the modern baseline conditions of the bay and can be used as a reference for changing paleoenvironmental parameters recorded in the box cores. The 14 sampling locations were chosen in the bay to cover the wide diversity of fluvial and marine-influenced environments on both sides of the shipping channel.

Tank 241-AY-101 Privatization Push Mode Core Sampling and Analysis Plan

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

TEMPLETON, A.M.

2000-05-19

This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for samples obtained from tank 241-AY-101. The purpose of this sampling event is to obtain information about the characteristics of the contents of 241-AY-101 required to satisfy ''Data Quality Objectives For RPP Privatization Phase I: Confirm Tank T Is An Appropriate Feed Source For High-Level Waste Feed Batch X(HLW DQO)' (Nguyen 1999a), ''Data Quality Objectives For TWRS Privatization Phase I: Confirm Tank T Is An Appropriate Feed Source For Low-Activity Waste Feed Butch X (LAW DQO) (Nguyen 1999b)'', ''Low Activity Wastemore » and High-Level Waste Feed Data Quality Objectives (L&H DQO)'' (Patello et al. 1999), and ''Characterization Data Needs for Development, Design, and Operation of Retrieval Equipment Developed through the Data Quality Objective Process (Equipment DQO)'' (Bloom 1996). Special instructions regarding support to the LAW and HLW DQOs are provided by Baldwin (1999). Push mode core samples will be obtained from risers 15G and 150 to provide sufficient material for the chemical analyses and tests required to satisfy these data quality objectives. The 222-S Laboratory will extrude core samples; composite the liquids and solids; perform chemical analyses on composite and segment samples; archive half-segment samples; and provide sub-samples to the Process Chemistry Laboratory. The Process Chemistry Laboratory will prepare test plans and perform process tests to evaluate the behavior of the 241-AY-101 waste undergoing the retrieval and treatment scenarios defined in the applicable DQOs. Requirements for analyses of samples originating in the process tests will be documented in the corresponding test plans and are not within the scope of this SAP.« less

Method and apparatus utilizing ionizing and microwave radiation for saturation determination of water, oil and a gas in a core sample

DOEpatents

Maerefat, Nicida L.; Parmeswar, Ravi; Brinkmeyer, Alan D.; Honarpour, Mehdi

1994-01-01

A system for determining the relative permeabilities of gas, water and oil in a core sample has a microwave emitter/detector subsystem and an X-ray emitter/detector subsystem. A core holder positions the core sample between microwave absorbers which prevent diffracted microwaves from reaching a microwave detector where they would reduce the signal-to-noise ratio of the microwave measurements. The microwave emitter/detector subsystem and the X-ray emitter/detector subsystem each have linear calibration characteristics, allowing one subsystem to be calibrated with respect to the other subsystem. The dynamic range of microwave measurements is extended through the use of adjustable attenuators. This also facilitates the use of core samples with wide diameters. The stratification characteristics of the fluids may be observed with a windowed cell separator at the outlet of the core sample. The condensation of heavy hydrocarbon gas and the dynamic characteristics of the fluids are observed with a sight glass at the outlet of the core sample.

Method and apparatus utilizing ionizing and microwave radiation for saturation determination of water, oil and a gas in a core sample

DOEpatents

Maerefat, N.L.; Parmeswar, R.; Brinkmeyer, A.D.; Honarpour, M.

1994-08-23

A system is described for determining the relative permeabilities of gas, water and oil in a core sample has a microwave emitter/detector subsystem and an X-ray emitter/detector subsystem. A core holder positions the core sample between microwave absorbers which prevent diffracted microwaves from reaching a microwave detector where they would reduce the signal-to-noise ratio of the microwave measurements. The microwave emitter/detector subsystem and the X-ray emitter/detector subsystem each have linear calibration characteristics, allowing one subsystem to be calibrated with respect to the other subsystem. The dynamic range of microwave measurements is extended through the use of adjustable attenuators. This also facilitates the use of core samples with wide diameters. The stratification characteristics of the fluids may be observed with a windowed cell separator at the outlet of the core sample. The condensation of heavy hydrocarbon gas and the dynamic characteristics of the fluids are observed with a sight glass at the outlet of the core sample. 11 figs.

Development of lunar drill to take core samples to 100-foot depths

NASA Technical Reports Server (NTRS)

1967-01-01

Lunar drill takes lunar surface cores to depths of 100 feet and is being developed to the samples at greater depths. The wireline drill system has been adapted to operate in the lunar environment by providing a sealed dc motor and solid metallic base lubricants.

A tubular-coring device for use in biogeochemical sampling of succulent and pulpy plants

USGS Publications Warehouse

Campbell, W.L.

1986-01-01

A hand-operated, tubular-coring device developed for use in biogeochemical sampling of succulent and pulpy plants is described. The sampler weighs about 500 g (1.1 lb); and if 25 ?? 175 mm (1 ?? 7 in) screw-top test tubes are used as sample containers, the complete sampling equipment kit is easily portable, having both moderate bulk and weight. ?? 1986.

Tank 241-AY-101 Privatization Push Mode Core Sampling and Analysis Plan

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

TEMPLETON, A.M.

2000-01-12

This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for samples obtained from tank 241-AY-101. The purpose of this sampling event is to obtain information about the characteristics of the contents of 241-AY-101 required to satisfy Data Quality Objectives For RPP Privatization Phase I: Confirm Tank T Is An Appropriate Feed Source For High-Level Waste Feed Batch X(HLW DQO) (Nguyen 1999a), Data Quality Objectives For TWRS Privatization Phase I : Confirm Tank T Is An Appropriate Feed Source For Low-Activity Waste Feed Batch X (LAW DQO) (Nguyen 1999b), Low Activitymore » Waste and High-Level Waste Feed Data Quality Objectives (L and H DQO) (Patello et al. 1999), and Characterization Data Needs for Development, Design, and Operation of Retrieval Equipment Developed through the Data Quality Objective Process (Equipment DQO) (Bloom 1996). Special instructions regarding support to the LAW and HLW DQOs are provided by Baldwin (1999). Push mode core samples will be obtained from risers 15G and 150 to provide sufficient material for the chemical analyses and tests required to satisfy these data quality objectives. The 222-S Laboratory will extrude core samples; composite the liquids and solids; perform chemical analyses on composite and segment samples; archive half-segment samples; and provide subsamples to the Process Chemistry Laboratory. The Process Chemistry Laboratory will prepare test plans and perform process tests to evaluate the behavior of the 241-AY-101 waste undergoing the retrieval and treatment scenarios defined in the applicable DQOs. Requirements for analyses of samples originating in the process tests will be documented in the corresponding test plans and are not within the scope of this SAP.« less

Water isotopic ratios from a continuously melted ice core sample

NASA Astrophysics Data System (ADS)

Gkinis, V.; Popp, T. J.; Blunier, T.; Bigler, M.; Schüpbach, S.; Kettner, E.; Johnsen, S. J.

2011-11-01

A new technique for on-line high resolution isotopic analysis of liquid water, tailored for ice core studies is presented. We built an interface between a Wavelength Scanned Cavity Ring Down Spectrometer (WS-CRDS) purchased from Picarro Inc. and a Continuous Flow Analysis (CFA) system. The system offers the possibility to perform simultaneuous water isotopic analysis of δ18O and δD on a continuous stream of liquid water as generated from a continuously melted ice rod. Injection of sub μl amounts of liquid water is achieved by pumping sample through a fused silica capillary and instantaneously vaporizing it with 100% efficiency in a~home made oven at a temperature of 170 °C. A calibration procedure allows for proper reporting of the data on the VSMOW-SLAP scale. We apply the necessary corrections based on the assessed performance of the system regarding instrumental drifts and dependance on the water concentration in the optical cavity. The melt rates are monitored in order to assign a depth scale to the measured isotopic profiles. Application of spectral methods yields the combined uncertainty of the system at below 0.1‰ and 0.5‰ for δ18O and δD, respectively. This performance is comparable to that achieved with mass spectrometry. Dispersion of the sample in the transfer lines limits the temporal resolution of the technique. In this work we investigate and assess these dispersion effects. By using an optimal filtering method we show how the measured profiles can be corrected for the smoothing effects resulting from the sample dispersion. Considering the significant advantages the technique offers, i.e. simultaneuous measurement of δ18O and δD, potentially in combination with chemical components that are traditionally measured on CFA systems, notable reduction on analysis time and power consumption, we consider it as an alternative to traditional isotope ratio mass spectrometry with the possibility to be deployed for field ice core studies. We present

A New Method of Stress Measurement Based upon Elastic Deformation of Core Sample with Stress Relief by Drilling

NASA Astrophysics Data System (ADS)

Ito, T.; Funato, A.; Tamagawa, T.; Tezuka, K.; Yabe, Y.; Abe, S.; Ishida, A.; Ogasawara, H.

2017-12-01

When rock is cored at depth by drilling, anisotropic expansion occurs with the relief of anisotropic rock stresses, resulting in a sinusoidal variation of core diameter with a period of 180 deg. in the core roll angle. The circumferential variation of core diameter is given theoretically as a function of rock stresses. These new findings can lead various ideas to estimate the rock stress from circumferential variation of core diameter measured after the core retrieving. In the simplest case when a single core sample is only available, the difference between the maximum and minimum components of rock stress in a plane perpendicular to the drilled hole can be estimated from the maximum and minimum core diameters (see the detail in, Funato and Ito, IJRMMS, 2017). The advantages of this method include, (i) much easier measurement operation than those in other in-situ or in-lab estimation methods, and (ii) applicability in high stress environment where stress measurements need pressure for packers or pumping system for the hydro-fracturing methods higher than their tolerance levels. We have successfully tested the method at deep seismogenic zones in South African gold mines, and we are going to apply it to boreholes collared at 3 km depth and intersecting a M5.5 rupture plane several hundred meters below the mine workings in the ICDP project of "Drilling into Seismogenic zones of M2.0 - M5.5 earthquakes in deep South African gold mines" (DSeis) (e.g., http://www.icdp-online.org/projects/world/africa/orkney-s-africa/details/). If several core samples with different orientation are available, all of three principal components of 3D rock stress can be estimated. To realize this, we should have several boreholes drilled in different directions in a rock mass where the stress field is considered to be uniform. It is commonly carried out to dill boreholes in different directions from a mine gallery. Even in a deep borehole drilled vertically from the ground surface, the

Earthquake source parameters determined using the SAFOD Pilot Hole vertical seismic array

NASA Astrophysics Data System (ADS)

Imanishi, K.; Ellsworth, W. L.; Prejean, S. G.

2003-12-01

We determined source parameters of microearthquakes occurring at Parkfield, CA, using the SAFOD Pilot Hole vertical seismic array. The array consists of 32 stations with 3-component 15 Hz geophones at 40 meter spacing (856 to 2096 m depth) The site is about 1.8 km southwest of a segment of the San Andreas fault characterized by a combination of aseismic creep and repeating microearthquakes. We analyzed seismograms recorded at sample rates of 1kHz or 2kHz. Spectra have high signal-to-noise ratios at frequencies up to 300-400 Hz, showing these data include information on source processes of microearthquakes. By comparing spectra and waveforms at different levels of the array, we observe how attenuation and scattering in the shallow crust affect high-frequency waves. We estimated spectral level (Ω 0), corner frequency (fc) and path-averaged attenuation (Q) at each level of the array by fitting an omega squared model to displacement spectra. While the spectral level changes smoothly with depth, there is significant scatter in fc and Q due to the strong trade-off between these parameters. Because we expect source parameters to vary systematically with depth, we impose a smoothness constraint on Q, Ω 0 and fc as a function of depth. For some of the nearby events, take-off angles to the different levels of the array span a significant part of the focal sphere. Therefore corner frequencies should also change with depth. We smooth measurements using a linear first-difference operator that links Q, Ω 0 and fc at one level to the levels above and below, and use Akaike_fs Bayesian Information Criterion (ABIC) to weight the smoothing operators. We applied this approach to events with high signal-to-noise ratios. For the results with the minimum ABIC, fc does not scatter and Q decreases with decreasing depth. Seismic moments were determined by the spectral level and range from 109 and 1012 Nm. Source radii were estimated from the corner frequency using the circular crack

Synthesis, characterization and nitrite ion sensing performance of reclaimable composite samples through a core-shell structure

NASA Astrophysics Data System (ADS)

Cui, Xiao; Yuqing, Zhao; Cui, Jiantao; Zheng, Qian; Bo, Wang

2018-02-01

The following paper reported and discussed a nitrite ion optical sensing platform based on a core-shell structure, using superamagnetic nanoparticles as the core, a silica molecular sieve MCM-41 as the shell and two rhodamine derivatives as probe, respectively. This superamagnetic core made this sensing platform reclaimable after finishing nitrite ion sensing procedure. This sensing platform was carefully characterized by means of electron microscopy images, porous structure analysis, magnetic response, IR spectra and thermal stability analysis. Detailed analysis suggested that the emission of these composite samples was quenchable by nitrite ion, showing emission turn off effect. A static sensing mechanism based on an additive reaction between chemosensors and nitrite ion was proposed. These composite samples followed Demas quenching equation against different nitrite ion concentrations. Limit of detection value was obtained as low as 0.4 μM. It was found that, after being quenched by nitrite ion, these composite samples could be reclaimed and recovered by sulphamic acid, confirming their recyclability.

Tank Vapor Sampling and Analysis Data Package for Tank 241-Z-361 Sampled 09/22/1999 and 09/271999 During Sludge Core Removal

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

VISWANATH, R.S.

This data package presents sampling data and analytical results from the September 22 and 27, 1999, headspace vapor sampling of Hanford Site Tank 241-2-361 during sludge core removal. The Lockheed Martin Hanford Corporation (LMHC) sampling team collected the samples and Waste Management Laboratory (WML) analyzed the samples in accordance with the requirements specified in the 241-2361 Sludge Characterization Sampling and Analysis Plan, (SAP), HNF-4371, Rev. 1, (Babcock and Wilcox Hanford Corporation, 1999). Six SUMMA{trademark} canister samples were collected on each day (1 ambient field blank and 5 tank vapor samples collected when each core segment was removed). The samples weremore » radiologically released on September 28 and October 4, 1999, and received at the laboratory on September 29 and October 6, 1999. Target analytes were not detected at concentrations greater than their notification limits as specified in the SAP. Analytical results for the target analytes and tentatively identified compounds (TICs) are presented in Section 2.2.2 starting on page 2B-7. Three compounds identified for analysis in the SAP were analyzed as TICs. The discussion of this modification is presented in Section 2.2.1.2.« less

Active AirCore Sampling: Constraining Point Sources of Methane and Other Gases with Fixed Wing Unmanned Aerial Systems

NASA Astrophysics Data System (ADS)

Bent, J. D.; Sweeney, C.; Tans, P. P.; Newberger, T.; Higgs, J. A.; Wolter, S.

2017-12-01

Accurate estimates of point source gas emissions are essential for reconciling top-down and bottom-up greenhouse gas measurements, but sampling such sources is challenging. Remote sensing methods are limited by resolution and cloud cover; aircraft methods are limited by air traffic control clearances, and the need to properly determine boundary layer height. A new sampling approach leverages the ability of unmanned aerial systems (UAS) to measure all the way to the surface near the source of emissions, improving sample resolution, and reducing the need to characterize a wide downstream swath, or measure to the full height of the planetary boundary layer (PBL). The "Active-AirCore" sampler, currently under development, will fly on a fixed wing UAS in Class G airspace, spiraling from the surface to 1200 ft AGL around point sources such as leaking oil wells to measure methane, carbon dioxide and carbon monoxide. The sampler collects a 100-meter long sample "core" of air in an 1/8" passivated stainless steel tube. This "core" is run on a high-precision instrument shortly after the UAS is recovered. Sample values are mapped to a specific geographic location by cross-referencing GPS and flow/pressure metadata, and fluxes are quantified by applying Gauss's theorem to the data, mapped onto the spatial "cylinder" circumscribed by the UAS. The AirCore-Active builds off the sampling ability and analytical approach of the related AirCore sampler, which profiles the atmosphere passively using a balloon launch platform, but will add an active pumping capability needed for near-surface horizontal sampling applications. Here, we show design elements, laboratory and field test results for methane, describe the overall goals of the mission, and discuss how the platform can be adapted, with minimal effort, to measure other gas species.

Tank 241-AZ-102 Privatization Push Mode Core Sampling and Analysis Plan

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

RASMUSSEN, J.H.

1999-08-02

This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for samples obtained from tank 241-AZ-102. The purpose of this sampling event is to obtain information about the characteristics of the contents of 241-AZ-102 required to satisfy the Data Quality Objectives For TWRS Privatization Phase I: Confirm Tank TIS An Appropriate Feed Source For High-Level Waste Feed Batch X(HLW DQO) (Nguyen 1999a), Data Quality Objectives For TWRS Privatization Phase 1: Confirm Tank TIS An Appropriate Feed Source For Low-Activity Waste Feed Batch X (LAW DQO) (Nguyen 1999b), Low Activity Waste andmore » High Level Waste Feed Data Quality Objectives (L&H DQO) (Patello et al. 1999) and Characterization Data Needs for Development, Design, and Operation of Retrieval Equipment Developed through the Data Quality Objective Process (Equipment DQO) (Bloom 1996). The Tank Characterization Technical Sampling Basis document (Brown et al. 1998) indicates that these issues, except the Equipment DQO apply to tank 241-AZ-102 for this sampling event. The Equipment DQO is applied for shear strength measurements of the solids segments only. Poppiti (1999) requires additional americium-241 analyses of the sludge segments. Brown et al. (1998) also identify safety screening, regulatory issues and provision of samples to the Privatization Contractor(s) as applicable issues for this tank. However, these issues will not be addressed via this sampling event. Reynolds et al. (1999) concluded that information from previous sampling events was sufficient to satisfy the safety screening requirements for tank 241 -AZ-102. Push mode core samples will be obtained from risers 15C and 24A to provide sufficient material for the chemical analyses and tests required to satisfy these data quality objectives. The 222-S Laboratory will extrude core samples, composite the liquids and solids, perform chemical

AirCore-HR: a high-resolution column sampling to enhance the vertical description of CH4 and CO2

NASA Astrophysics Data System (ADS)

Membrive, Olivier; Crevoisier, Cyril; Sweeney, Colm; Danis, François; Hertzog, Albert; Engel, Andreas; Bönisch, Harald; Picon, Laurence

2017-06-01

An original and innovative sampling system called AirCore was presented by NOAA in 2010 Karion et al.(2010). It consists of a long ( > 100 m) and narrow ( < 1 cm) stainless steel tube that can retain a profile of atmospheric air. The captured air sample has then to be analyzed with a gas analyzer for trace mole fraction. In this study, we introduce a new AirCore aiming to improve resolution along the vertical with the objectives to (i) better capture the vertical distribution of CO2 and CH4, (ii) provide a tool to compare AirCores and validate the estimated vertical resolution achieved by AirCores. This (high-resolution) AirCore-HR consists of a 300 m tube, combining 200 m of 0.125 in. (3.175 mm) tube and a 100 m of 0.25 in. (6.35 mm) tube. This new configuration allows us to achieve a vertical resolution of 300 m up to 15 km and better than 500 m up to 22 km (if analysis of the retained sample is performed within 3 h). The AirCore-HR was flown for the first time during the annual StratoScience campaign from CNES in August 2014 from Timmins (Ontario, Canada). High-resolution vertical profiles of CO2 and CH4 up to 25 km were successfully retrieved. These profiles revealed well-defined transport structures in the troposphere (also seen in CAMS-ECMWF high-resolution forecasts of CO2 and CH4 profiles) and captured the decrease of CO2 and CH4 in the stratosphere. The multi-instrument gondola also carried two other low-resolution AirCore-GUF that allowed us to perform direct comparisons and study the underlying processing method used to convert the sample of air to greenhouse gases vertical profiles. In particular, degrading the AirCore-HR derived profiles to the low resolution of AirCore-GUF yields an excellent match between both sets of CH4 profiles and shows a good consistency in terms of vertical structures. This fully validates the theoretical vertical resolution achievable by AirCores. Concerning CO2 although a good agreement is found in terms of vertical structure

Design review report for rotary mode core sample truck (RMCST) modifications for flammable gas tanks, preliminary design

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

Corbett, J.E.

1996-02-01

This report documents the completion of a preliminary design review for the Rotary Mode Core Sample Truck (RMCST) modifications for flammable gas tanks. The RMCST modifications are intended to support core sampling operations in waste tanks requiring flammable gas controls. The objective of this review was to validate basic design assumptions and concepts to support a path forward leading to a final design. The conclusion reached by the review committee was that the design was acceptable and efforts should continue toward a final design review.

Core belief content examined in a large sample of patients using online cognitive behaviour therapy.

PubMed

Millings, Abigail; Carnelley, Katherine B

2015-11-01

Computerised cognitive behavioural therapy provides a unique opportunity to collect and analyse data regarding the idiosyncratic content of people's core beliefs about the self, others and the world. 'Beating the Blues' users recorded a core belief derived through the downward arrow technique. Core beliefs from 1813 mental health patients were coded into 10 categories. The most common were global self-evaluation, attachment, and competence. Women were more likely, and men were less likely (than chance), to provide an attachment-related core belief; and men were more likely, and women less likely, to provide a self-competence-related core belief. This may be linked to gender differences in sources of self-esteem. Those who were suffering from anxiety were more likely to provide power- and control-themed core beliefs and less likely to provide attachment core beliefs than chance. Finally, those who had thoughts of suicide in the preceding week reported less competence themed core beliefs and more global self-evaluation (e.g., 'I am useless') core beliefs than chance. Concurrent symptom level was not available. The sample was not nationally representative, and featured programme completers only. Men and women may focus on different core beliefs in the context of CBT. Those suffering anxiety may need a therapeutic focus on power and control. A complete rejection of the self (not just within one domain, such as competence) may be linked to thoughts of suicide. Future research should examine how individual differences and symptom severity influence core beliefs. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

Permeability of the San Andreas Fault Zone at Depth

NASA Astrophysics Data System (ADS)

Rathbun, A. P.; Song, I.; Saffer, D.

2010-12-01

Quantifying fault rock permeability is important toward understanding both the regional hydrologic behavior of fault zones, and poro-elastic processes that affect fault mechanics by mediating effective stress. These include long-term fault strength as well as dynamic processes that may occur during earthquake slip, including thermal pressurization and dilatancy hardening. Despite its importance, measurements of fault zone permeability for relevant natural materials are scarce, owing to the difficulty of coring through active fault zones seismogenic depths. Most existing measurements of fault zone permeability are from altered surface samples or from thinner, lower displacement faults than the SAF. Here, we report on permeability measurements conducted on gouge from the actively creeping Central Deformation Zone (CDZ) of the San Andreas Fault, sampled in the SAFOD borehole at a depth of ~2.7 km (Hole G, Run 4, sections 4,5). The matrix of the gouge in this interval is predominantly composed of particles <10 µm, with ~5 vol% clasts of serpentinite, very fine-grained sandstone, and siltstone. The 2.6 m-thick CDZ represents the main fault trace and hosts ~90% of the active slip on the SAF at this location, as documented by repeated casing deformation surveys. We measured permeability in two different configurations: (1) in a uniaxial pressure cell, in which a sample is placed into a rigid steel ring which imposes a zero lateral strain condition and subjected to axial load, and (2) in a standard triaxial system under isostatic stress conditions. In the uniaxial configuration, we obtained permeabilities at axial effective stresses up to 90 MPa, and in the triaxial system up to 10 MPa. All experiments were conducted on cylindrical subsamples of the SAFOD core 25 mm in diameter, with lengths ranging from 18mm to 40mm, oriented for flow approximately perpendicular to the fault. In uniaxial tests, permeability is determined by running constant rate of strain (CRS) tests up

Management of intraductal papilloma without atypia of the breast diagnosed on core biopsy: Size and sampling matter.

PubMed

Symbol, Brittany; Ricci, Andrew

2018-04-23

Due to the potential for atypia (atypical ductal or lobular hyperplasia) or carcinoma (in situ or invasive) on excision, aggressive reflex surgical excision protocols following core biopsy diagnosis of papillary lesions of the breast (ie, intraductal papilloma) are commonplace. Concepts in risk stratification, including radiologic-pathologic correlation, are emerging in an effort to curb unnecessary surgeries. To this end, we examined all excised intraductal papillomas diagnosed at our institution from 2010-2015 (N = 336) and found an overall atypia rate of 20%. To investigate further, we stratified all excised papillomas according to total lesion size (range = 1-40 mm) and found that the atypia rate for lesions ≤1.2 cm (16% with atypia) was statistically significantly lower (P = .008) than the atypia rate for lesions >1.2 cm (36% with atypia). To explore to effects of radiologic-pathologic correlation on the ability of the core biopsy to accurately predict nonatypical lesions we assessed thirteen consecutive paired nonatypical core biopsy/follow-up surgical excision specimens for the percent of the total lesion (on imaging) sampled by the core biopsy (measured histologically). None of the thirteen paired specimens showed upgrade on excision (0/13); the percent of total lesion sampled by biopsy in this cohort averaged 59%. We propose that in the absence of discordant clinical/radiological findings, small lesions (≤1.2 cm) with radiologic-pathologic concordance (>50% sampling of total lesion by core biopsy) may safely forego surgery for close clinical and radiographic follow-up. © 2018 Wiley Periodicals, Inc.

Analyses of native water, core material, and elutriate samples collected from the Atchafalaya River and Atchafalaya Bay

USGS Publications Warehouse

Demas, Charles R.

1977-01-01

During October and November 1976 the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, collected native water and core material from 14 sites along the Atchafalya River in Louisiana (from the head of Whiskey Bay Pilot Channel to American Pass) and 5 sites in Atchafalya Bay for evaluation of possible environmental effects of a proposed channel-enlargement project. Core material from all river sites and one bay site was collected to a depth of 50 feet (15 meters). At the remaining bay sites, samples were collected to a depth of less than 6 inches (15 centimeters) using a pipe dredge. Core material and native water were analyzed (separately and as elutriate samples prepared from mixtures) for selected metals, nutrients, organic compounds, and physical characteristics. No interpretation of the data is given. (Woodard-USGS)

The effect of acidified sample storage time on the determination of trace element concentration in ice cores by ICP-SFMS

NASA Astrophysics Data System (ADS)

Uglietti, C.; Gabrielli, P.; Lutton, A.; Olesik, J.; Thompson, L. G.

2012-12-01

Trace elements in micro-particles entrapped in ice cores are a valuable proxy of past climate and environmental variations. Inductively coupled plasma sector field mass spectrometry (ICP-SFMS) is generally recognized as a sensitive and accurate technique for the quantification of ultra-trace element concentrations in ice cores. Usually, ICP-SFMS analyses of ice core samples are performed by melting and acidifying aliquots. Acidification is important to transfer trace elements from particles into solution by partial and/or complete dissolution. Only elements in solution and in sufficiently small particles will be vaporized and converted to elemental ions in the plasma for detection by ICP-SFMS. However, experimental results indicate that differences in acidified sample storage time at room temperature may lead to the recovery of different trace element fractions. Moreover, different lithologies of the relatively abundant crustal material entrapped in the ice matrix could also influence the fraction of trace elements that are converted into elemental ions in the plasma. These factors might affect the determination of trace elements concentrations in ice core samples and hamper the comparison of results obtained from ice cores from different locations and/or epochs. In order to monitor the transfer of elements from particles into solution in acidified melted ice core samples during storage, a test was performed on sections from nine ice cores retrieved from low latitude drilling sites around the world. When compared to ice cores from polar regions, these samples are characterized by a relative high content of micro-particles that may leach trace elements into solution differently. Of the nine ice cores, five are from the Tibetan Plateau (Dasuopu, Guliya, Naimonanyi, Puruogangri and Dunde), two from the Andes (Quelccaya and Huascaran), one from Africa (Kilimanjaro) and one from the Eastern Alps (Ortles). These samples were decontaminated by triple rinsing, melted and

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.

Empirical relations of rock properties of outcrop and core samples from the Northwest German Basin for geothermal drilling

NASA Astrophysics Data System (ADS)

Reyer, D.; Philipp, S. L.

2014-09-01

Information about geomechanical and physical rock properties, particularly uniaxial compressive strength (UCS), are needed for geomechanical model development and updating with logging-while-drilling methods to minimise costs and risks of the drilling process. The following parameters with importance at different stages of geothermal exploitation and drilling are presented for typical sedimentary and volcanic rocks of the Northwest German Basin (NWGB): physical (P wave velocities, porosity, and bulk and grain density) and geomechanical parameters (UCS, static Young's modulus, destruction work and indirect tensile strength both perpendicular and parallel to bedding) for 35 rock samples from quarries and 14 core samples of sandstones and carbonate rocks. With regression analyses (linear- and non-linear) empirical relations are developed to predict UCS values from all other parameters. Analyses focus on sedimentary rocks and were repeated separately for clastic rock samples or carbonate rock samples as well as for outcrop samples or core samples. Empirical relations have high statistical significance for Young's modulus, tensile strength and destruction work; for physical properties, there is a wider scatter of data and prediction of UCS is less precise. For most relations, properties of core samples plot within the scatter of outcrop samples and lie within the 90% prediction bands of developed regression functions. The results indicate the applicability of empirical relations that are based on outcrop data on questions related to drilling operations when the database contains a sufficient number of samples with varying rock properties. The presented equations may help to predict UCS values for sedimentary rocks at depth, and thus develop suitable geomechanical models for the adaptation of the drilling strategy on rock mechanical conditions in the NWGB.

Analyses of water, core material, and elutriate samples collected near Buras, Louisiana (New Orleans to Venice, Louisiana, Hurricane Protection Project)

USGS Publications Warehouse

Leone, Harold A.

1977-01-01

Eight core-material-sampling sites were chosen by the U.S. Army Corps of Engineers as possible borrow areas for fill material to be used in levee contruction near Buras, La. Eleven receiving-water sites also were selected to represent the water that will contact the porposed levees. Analyses of selected nutrients, metals, pesticides, and other organic constitutents were performed upon these bed-material and native-water samples as well as upon elutriate samples of specific core material-receiving water systems. The results of these analyses are presented without interpretation. (Woodard-USGS)

A search at the millijansky level for milli-arcsecond cores in a complete sample of radio galaxies

NASA Technical Reports Server (NTRS)

Wehrle, A. E.; Preston, R. A.; Meier, D. L.; Gorenstein, M. V.; Shapiro, I. I.; Rogers, A. E. E.; Rius, A.

1984-01-01

A complete sample of 26 extended radio galaxies was observed at 2.29 GHz with the Mark III VLBI system. The fringe spacing was about 3 milli-arcsec, and the detection limit was about 2 millijanskys. Half of the galaxies were found to possess milli-arcsec radio cores. In all but three sources, the nuclear flux density was less than 0.04 of the total flux density. Galaxies with high optical luminosity (less than -21.2) were more likely than less luminous galaxies to contain a detectable milliparcsec radio core (69 percent vs. 20 percent). For objects with arcsec cores, 80 percent were found to have a milli-arcsec core, even though the milli-arcsec object did not always contribute the greater part of the arcsec flux density.

Nondestructive continuous physical property measurements of core samples recovered from hole B, Taiwan Chelungpu-Fault Drilling Project

NASA Astrophysics Data System (ADS)

Hirono, Tetsuro; Yeh, En-Chao; Lin, Weiren; Sone, Hiroki; Mishima, Toshiaki; Soh, Wonn; Hashimoto, Yoshitaka; Matsubayashi, Osamu; Aoike, Kan; Ito, Hisao; Kinoshita, Masataka; Murayama, Masafumi; Song, Sheng-Rong; Ma, Kuo-Fong; Hung, Jih-Hao; Wang, Chien-Ying; Tsai, Yi-Ben; Kondo, Tomomi; Nishimura, Masahiro; Moriya, Soichi; Tanaka, Tomoyuki; Fujiki, Toru; Maeda, Lena; Muraki, Hiroaki; Kuramoto, Toshikatsu; Sugiyama, Kazuhiro; Sugawara, Toshikatsu

2007-07-01

The Taiwan Chelungpu-Fault Drilling Project was undertaken in 2002 to investigate the faulting mechanism of the 1999 Mw 7.6 Taiwan Chi-Chi earthquake. Hole B penetrated the Chelungpu fault, and core samples were recovered from between 948.42- and 1352.60-m depth. Three major zones, designated FZB1136 (fault zone at 1136-m depth in hole B), FZB1194, and FZB1243, were recognized in the core samples as active fault zones within the Chelungpu fault. Nondestructive continuous physical property measurements, conducted on all core samples, revealed that the three major fault zones were characterized by low gamma ray attenuation (GRA) densities and high magnetic susceptibilities. Extensive fracturing and cracks within the fault zones and/or loss of atoms with high atomic number, but not a measurement artifact, might have caused the low GRA densities, whereas the high magnetic susceptibility values might have resulted from the formation of magnetic minerals from paramagnetic minerals by frictional heating. Minor fault zones were characterized by low GRA densities and no change in magnetic susceptibility, and the latter may indicate that these minor zones experienced relatively low frictional heating. Magnetic susceptibility in a fault zone may be key to the determination that frictional heating occurred during an earthquake on the fault.

Multiplatform sampling (ship, aircraft, and satellite) of a Gulf Stream warm core ring

NASA Technical Reports Server (NTRS)

Smith, Raymond C.; Brown, Otis B.; Hoge, Frank E.; Baker, Karen S.; Evans, Robert H.

1987-01-01

The purpose of this paper is to demonstrate the ability to meet the need to measure distributions of physical and biological properties of the ocean over large areas synoptically and over long time periods by means of remote sensing utilizing contemporaneous buoy, ship, aircraft, and satellite (i.e., multiplatform) sampling strategies. A mapping of sea surface temperature and chlorophyll fields in a Gulf Stream warm core ring using the multiplatform approach is described. Sampling capabilities of each sensing system are discussed as background for the data collected by means of these three dissimilar methods. Commensurate space/time sample sets from each sensing system are compared, and their relative accuracies in space and time are determined. The three-dimensional composite maps derived from the data set provide a synoptic perspective unobtainable from single platforms alone.

Two-dimensional T2 distribution mapping in rock core plugs with optimal k-space sampling.

PubMed

Xiao, Dan; Balcom, Bruce J

2012-07-01

Spin-echo single point imaging has been employed for 1D T(2) distribution mapping, but a simple extension to 2D is challenging since the time increase is n fold, where n is the number of pixels in the second dimension. Nevertheless 2D T(2) mapping in fluid saturated rock core plugs is highly desirable because the bedding plane structure in rocks often results in different pore properties within the sample. The acquisition time can be improved by undersampling k-space. The cylindrical shape of rock core plugs yields well defined intensity distributions in k-space that may be efficiently determined by new k-space sampling patterns that are developed in this work. These patterns acquire 22.2% and 11.7% of the k-space data points. Companion density images may be employed, in a keyhole imaging sense, to improve image quality. T(2) weighted images are fit to extract T(2) distributions, pixel by pixel, employing an inverse Laplace transform. Images reconstructed with compressed sensing, with similar acceleration factors, are also presented. The results show that restricted k-space sampling, in this application, provides high quality results. Copyright © 2012 Elsevier Inc. All rights reserved.

Data precision of X-ray fluorescence (XRF) scanning of discrete samples with the ITRAX XRF core-scanner exemplified on loess-paleosol samples

NASA Astrophysics Data System (ADS)

Profe, Jörn; Ohlendorf, Christian

2017-04-01

XRF-scanning is the state-of-the-art technique for geochemical analyses in marine and lacustrine sedimentology for more than a decade. However, little attention has been paid to data precision and technical limitations so far. Using homogenized, dried and powdered samples (certified geochemical reference standards and samples from a lithologically-contrasting loess-paleosol sequence) minimizes many adverse effects that influence the XRF-signal when analyzing wet sediment cores. This allows the investigation of data precision under ideal conditions and documents a new application of the XRF core-scanner technology at the same time. Reliable interpretations of XRF results require data precision evaluation of single elements as a function of X-ray tube, measurement time, sample compaction and quality of peak fitting. Ten-fold measurement of each sample constitutes data precision. Data precision of XRF measurements theoretically obeys Poisson statistics. Fe and Ca exhibit largest deviations from Poisson statistics. The same elements show the least mean relative standard deviations in the range from 0.5% to 1%. This represents the technical limit of data precision achievable by the installed detector. Measurement times ≥ 30 s reveal mean relative standard deviations below 4% for most elements. The quality of peak fitting is only relevant for elements with overlapping fluorescence lines such as Ba, Ti and Mn or for elements with low concentrations such as Y, for example. Differences in sample compaction are marginal and do not change mean relative standard deviation considerably. Data precision is in the range reported for geochemical reference standards measured by conventional techniques. Therefore, XRF scanning of discrete samples provide a cost- and time-efficient alternative to conventional multi-element analyses. As best trade-off between economical operation and data quality, we recommend a measurement time of 30 s resulting in a total scan time of 30 minutes

Geochemical data for core and bottom-sediment samples collected in 2007 from Grand Lake O' the Cherokees, northeast Oklahoma

USGS Publications Warehouse

Fey, David L.; Becker, Mark F.; Smith, Kathleen S.

2010-01-01

Grand Lake O' the Cherokees is a large reservoir in northeast Oklahoma, below the confluence of the Neosho and Spring Rivers, both of which drain the Tri-State Mining District to the north. The Tri-State district covers an area of 1,200 mi2 (3,100 km2) and comprises Mississippi Valley-type lead-zinc deposits. A result of 120 years of mining activity is an estimated 75 million tons of processed mine tailings (chat) remaining in the district. Concerns of sediment quality and the possibility of human exposure to cadmium and lead through eating fish have led to several studies of the sediments in the Tri-State district. In order to record the transport and deposition of metals from the Tri-State district by the Spring and Neosho Rivers into Grand Lake O' the Cherokees, the U.S. Geological Survey collected 11 sediment cores and 15 bottom-sediment samples in September 2007. Subsamples from five selected cores and the bottom-sediment samples were analyzed for major and trace elements and forms of carbon. The sediment samples collected from the sediment-water interface had larger average concentrations of zinc, cadmium, and lead than local background. The core collected from the Spring River had the largest concentrations of mining-related elements. A core collected just south of Twin Bridges State Park, at the confluence of the Spring and Neosho Rivers, showed a mixing zone with more mining-related elements coming from the Spring River side. The element zinc showed the most definitive patterns in graphs depicting concentration-versus-depth profiles. A core collected from the main body of the reservoir showed affected sediment down to a depth of 85 cm (33 in). This core and two others appear to have penetrated to below mining-affected sediment.

Test of tree core sampling for screening of toxic elements in soils from a Norwegian site.

PubMed

Algreen, Mette; Rein, Arno; Legind, Charlotte N; Amundsen, Carl Einar; Karlson, Ulrich Gosewinkel; Trapp, Stefan

2012-04-01

Tree core samples have been used to delineate organic subsurface plumes. In 2009 and 2010, samples were taken at trees growing on a former dump site in Norway and analyzed for arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), and zinc (Zn). Concentrations in wood were in averages (dw) 30 mg/kg for Zn, 2 mg/kg for Cu, and < 1 mg/kg for Cd, Cr, As and Ni. The concentrations in wood samples from the polluted test site were compared to those derived from a reference site. For all except one case, mean concentrations from the test site were higher than those from the reference site, but the difference was small and not always significant. Differences between tree species were usually higher than differences between reference and test site. Furthermore, all these elements occur naturally, and Cu, Ni, and Zn are essential minerals. Thus, all trees will have a natural background of these elements, and the occurrence alone does not indicate soil pollution. For the interpretation of the results, a comparison to wood samples from an unpolluted reference site with same species and similar soil conditions is required. This makes the tree core screening method less reliable for heavy metals than, e.g., for chlorinated solvents.

Whole-rock analyses of core samples from the 1988 drilling of Kilauea Iki lava lake, Hawaii

USGS Publications Warehouse

Helz, Rosalind Tuthill; Taggart, Joseph E.

2010-01-01

This report presents and evaluates 64 major-element analyses of previously unanalyzed Kilauea Iki drill core, plus three samples from the 1959 and 1960 eruptions of Kilauea, obtained by X-ray fluorescence (XRF) analysis during the period 1992 to 1995. All earlier major-element analyses of Kilauea Iki core, obtained by classical (gravimetric) analysis, were reported and evaluated in Helz and others (1994). In order to assess how well the newer data compare with this earlier suite of analyses, a subset of 24 samples, which had been analyzed by classical analysis, was reanalyzed using the XRF technique; those results are presented and evaluated in this report also. The XRF analyses have not been published previously. This report also provides an overview of how the chemical variations observed in these new data fit in with the chemical zonation patterns and petrologic processes inferred in earlier studies of Kilauea Iki.

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

Chlorine-36 and cesium-137 in ice-core samples from mid-latitude glacial sites in the Northern Hemisphere

USGS Publications Warehouse

Green, J.R.; Cecil, L.D.; Synal, H.-A.; Kreutz, K.J.; Wake, C.P.; Naftz, D.L.; Frape, S.K.

2000-01-01

Chlorine-36 (36Cl) concentrations, 36Cl/Cl ratios, and 36Cl fluxes in ice-core samples collected from the Upper Fremont Glacier (UFG) in the Wind River Mountain Range, Wyoming, United States and the Nangpai Gosum Glacier (NGG) in the Himalayan Mountains, Nepal, were determined and compared with published results from the Dye-3 ice-core drilling site on the Greenland Ice Sheet. Cesium-137 (137Cs) concentrations in the NGG also were determined. The background fluxes for 36Cl for each glacial site were similar: (1.6??0.3)??10-2 atoms/cm2 s for the UFG samples, (0.7??0.1)??10-2 atoms/cm2 s for the NGG samples, and (0.4??0.1)??10-2 atoms/cm2 s for the Dye-3 samples. The 36Cl fluxes in ice that was deposited as snow during peak atmospheric nuclear weapon test (1957-1958) were (33??1)??10-2 atoms/cm2 s for the UFG site, (291??3)??10-2 atoms/cm2 s for the NGG site, and (124??5)??10-2 atoms/ cm2 s for the Dye-3 site. A weapon test period 137Cs concentration of 0.79??0.05 Bq/kg in the NGG ice core also was detected in the same section of ice that contained the largest 36Cl concentration. ?? 2000 Elsevier Science B.V. All rights reserved.

The WAIS Melt Monitor: An automated ice core melting system for meltwater sample handling and the collection of high resolution microparticle size distribution data

NASA Astrophysics Data System (ADS)

Breton, D. J.; Koffman, B. G.; Kreutz, K. J.; Hamilton, G. S.

2010-12-01

Paleoclimate data are often extracted from ice cores by careful geochemical analysis of meltwater samples. The analysis of the microparticles found in ice cores can also yield unique clues about atmospheric dust loading and transport, dust provenance and past environmental conditions. Determination of microparticle concentration, size distribution and chemical makeup as a function of depth is especially difficult because the particle size measurement either consumes or contaminates the meltwater, preventing further geochemical analysis. Here we describe a microcontroller-based ice core melting system which allows the collection of separate microparticle and chemistry samples from the same depth intervals in the ice core, while logging and accurately depth-tagging real-time electrical conductivity and particle size distribution data. This system was designed specifically to support microparticle analysis of the WAIS Divide WDC06A deep ice core, but many of the subsystems are applicable to more general ice core melting operations. Major system components include: a rotary encoder to measure ice core melt displacement with 0.1 millimeter accuracy, a meltwater tracking system to assign core depths to conductivity, particle and sample vial data, an optical debubbler level control system to protect the Abakus laser particle counter from damage due to air bubbles, a Rabbit 3700 microcontroller which communicates with a host PC, collects encoder and optical sensor data and autonomously operates Gilson peristaltic pumps and fraction collectors to provide automatic sample handling, melt monitor control software operating on a standard PC allowing the user to control and view the status of the system, data logging software operating on the same PC to collect data from the melting, electrical conductivity and microparticle measurement systems. Because microparticle samples can easily be contaminated, we use optical air bubble sensors and high resolution ice core density

Rare earth element geochemistry of outcrop and core samples from the Marcellus Shale

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

Noack, Clinton W.; Jain, Jinesh C.; Stegmeier, John

In this paper, we studied the geochemistry of the rare earth elements (REE) in eleven outcrop samples and six, depth-interval samples of a core from the Marcellus Shale. The REE are classically applied analytes for investigating depositional environments and inferring geochemical processes, making them of interest as potential, naturally occurring indicators of fluid sources as well as indicators of geochemical processes in solid waste disposal. However, little is known of the REE occurrence in the Marcellus Shale or its produced waters, and this study represents one of the first, thorough characterizations of the REE in the Marcellus Shale. In thesemore » samples, the abundance of REE and the fractionation of REE profiles were correlated with different mineral components of the shale. Namely, samples with a larger clay component were inferred to have higher absolute concentrations of REE but have less distinctive patterns. Conversely, samples with larger carbonate fractions exhibited a greater degree of fractionation, albeit with lower total abundance. Further study is necessary to determine release mechanisms, as well as REE fate-and-transport, however these results have implications for future brine and solid waste management applications.« less

Rare earth element geochemistry of outcrop and core samples from the Marcellus Shale

DOE PAGES

Noack, Clinton W.; Jain, Jinesh C.; Stegmeier, John; ...

2015-06-26

In this paper, we studied the geochemistry of the rare earth elements (REE) in eleven outcrop samples and six, depth-interval samples of a core from the Marcellus Shale. The REE are classically applied analytes for investigating depositional environments and inferring geochemical processes, making them of interest as potential, naturally occurring indicators of fluid sources as well as indicators of geochemical processes in solid waste disposal. However, little is known of the REE occurrence in the Marcellus Shale or its produced waters, and this study represents one of the first, thorough characterizations of the REE in the Marcellus Shale. In thesemore » samples, the abundance of REE and the fractionation of REE profiles were correlated with different mineral components of the shale. Namely, samples with a larger clay component were inferred to have higher absolute concentrations of REE but have less distinctive patterns. Conversely, samples with larger carbonate fractions exhibited a greater degree of fractionation, albeit with lower total abundance. Further study is necessary to determine release mechanisms, as well as REE fate-and-transport, however these results have implications for future brine and solid waste management applications.« less

Study of sample drilling techniques for Mars sample return missions

NASA Technical Reports Server (NTRS)

Mitchell, D. C.; Harris, P. T.

1980-01-01

To demonstrate the feasibility of acquiring various surface samples for a Mars sample return mission the following tasks were performed: (1) design of a Mars rover-mounted drill system capable of acquiring crystalline rock cores; prediction of performance, mass, and power requirements for various size systems, and the generation of engineering drawings; (2) performance of simulated permafrost coring tests using a residual Apollo lunar surface drill, (3) design of a rock breaker system which can be used to produce small samples of rock chips from rocks which are too large to return to Earth, but too small to be cored with the Rover-mounted drill; (4)design of sample containers for the selected regolith cores, rock cores, and small particulate or rock samples; and (5) design of sample handling and transfer techniques which will be required through all phase of sample acquisition, processing, and stowage on-board the Earth return vehicle. A preliminary design of a light-weight Rover-mounted sampling scoop was also developed.

Collection, analysis, and age-dating of sediment cores from 56 U.S. lakes and reservoirs sampled by the U.S. Geological Survey, 1992-2001

USGS Publications Warehouse

Van Metre, Peter; Wilson, Jennifer T.; Fuller, Christopher C.; Callender, Edward; Mahler, Barbara J.

2004-01-01

The U.S. Geological Survey Reconstructed Trends National Synthesis study collected sediment cores from 56 lakes and reservoirs between 1992 and 2001 across the United States. Most of the sampling was conducted as part of the National Water-Quality Assessment (NAWQA) Program. The primary objective of the study was to determine trends in particle-associated contaminants in response to urbanization; 47 of the 56 lakes are in or near one of 20 U.S. cities. Sampling was done with gravity, piston, and box corers from boats and push cores from boats or by wading, depending on the depth of water and thickness of sediment being sampled. Chemical analyses included major and trace elements, organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, cesium-137, and lead-210. Age-dating of the cores was done on the basis of radionuclide analyses and the position of the pre-reservoir land surface in the reservoir and, in a few cases, other chemical or lithologic depth-date markers. Dates were assigned in many cores on the basis of assumed constant mass accumulation between known depth-date markers. Dates assigned were supported using a variety of other date markers including first occurrence and peak concentrations of DDT and polychlorinated biphenyls and peak concentration of lead. A qualitative rating was assigned to each core on the basis of professional judgment to indicate the reliability of age assignments. A total of 122 cores were collected from the 56 lakes and age dates were assigned to 113 of them, representing 54 of the 56 lakes. Seventy-four of the 122 cores (61 percent) received a good rating for the assigned age dates, 28 cores (23 percent) a fair rating, and 11 cores (9 percent) a poor rating; nine cores (7 percent) had no dates assigned. An analysis of the influence of environmental factors on the apparent quality of age-dating of the cores concluded that the most important factor was the mass accumulation rate (MAR) of sediment: the

Petrophysical characterization of first ever drilled core samples from an active CO2 storage site, the German Ketzin Pilot Site - Comparison with long term experiments

NASA Astrophysics Data System (ADS)

Zemke, Kornelia; Liebscher, Axel

2014-05-01

Petrophysical properties like porosity and permeability are key parameters for a safe long-term storage of CO2 but also for the injection operation itself. These parameters may change during and/or after the CO2 injection due to geochemical reactions in the reservoir system that are triggered by the injected CO2. Here we present petrophysical data of first ever drilled cores from a newly drilled well at the active CO2 storage site - the Ketzin pilot site in the Federal State of Brandenburg, Germany. By comparison with pre-injection baseline data from core samples recovered prior to injection, the new samples provide the unique opportunity to evaluate the impact of CO2 on pore size related properties of reservoir and cap rocks at a real injection site under in-situ reservoir conditions. After injection of 61 000 tons CO2, an additional well was drilled and new rock cores were recovered. In total 100 core samples from the reservoir and the overlaying caprock were investigated by NMR relaxation. Permeability of 20 core samples was estimated by nitrogen and porosity by helium pycnometry. The determined data are comparable between pre-injection and post-injection core samples. The lower part of the reservoir sandstone is unaffected by the injected CO2. The upper part of the reservoir sandstone shows consistently slightly lower NMR porosity and permeability values in the post-injection samples when compared to the pre-injection data. This upper sandstone part is above the fluid level and CO2 present as a free gas phase and a possible residual gas saturation of the cores distorted the NMR results. The potash-containing drilling fluid can also influence these results: NMR investigation of twin samples from inner and outer parts of the cores show a reduced fraction of larger pores for the outer core samples together with lower porosities and T2 times. The drill mud penetration depth can be controlled by the added fluorescent tracer. Due to the heterogeneous character of the

Analytical test results for archived core composite samples from tanks 241-TY-101 and 241-TY-103

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

Beck, M.A.

1993-07-16

This report describes the analytical tests performed on archived core composite samples form a 1.085 sampling of the 241-TY-101 (101-TY) and 241-TY-103 (103-TY) single shell waste tanks. Both tanks are suspected of containing quantities of ferrocyanide compounds, as a result of process activities in the late 1950`s. Although limited quantities of the composite samples remained, attempts were made to obtain as much analytical information as possible, especially regarding the chemical and thermal properties of the material.

Core break-off mechanism

NASA Technical Reports Server (NTRS)

Myrick, Thomas M. (Inventor)

2003-01-01

A mechanism for breaking off and retaining a core sample of a drill drilled into a ground substrate has an outer drill tube and an inner core break-off tube sleeved inside the drill tube. The break-off tube breaks off and retains the core sample by a varying geometric relationship of inner and outer diameters with the drill tube. The inside diameter (ID) of the drill tube is offset by a given amount with respect to its outer diameter (OD). Similarly, the outside diameter (OD) of the break-off tube is offset by the same amount with respect to its inner diameter (ID). When the break-off tube and drill tube are in one rotational alignment, the two offsets cancel each other such that the drill can operate the two tubes together in alignment with the drill axis. When the tubes are rotated 180 degrees to another positional alignment, the two offsets add together causing the core sample in the break-off tube to be displaced from the drill axis and applying shear forces to break off the core sample.

Chemical composition of core samples from Newark Basin, a potential carbon sequestration site

NASA Astrophysics Data System (ADS)

Seltzer, A. M.; Yang, Q.; Goldberg, D.

2012-12-01

Injection of carbon dioxide into deep saline aquifers has been identified as a promising mitigation option of greenhouse gases, the successful management of which is considered to be one of the most urgent and important challenges. Given the high energy production in the New York metropolitan area, the Newark Basin region is considered to be a potential future sequestration site. However, the risk of an upward leak of sequestered CO2, especially to a shallow drinking water aquifer, is a key concern facing geological sequestration as a safe and viable mitigation option. In this study, we measured the chemical composition of 25 cores from various depths throughout Newark Basin as a precursor for an ex situ incubation experiment using these rock samples and aquifer water to simulate a leak event. Inductively coupled plasma mass spectrometry analysis of microwave-assisted digested rock powders and X-ray fluorescence analysis of the rock powders were conducted to obtain the concentrations of major and trace elements. Most of the major and trace elements show wide concentration ranges at one to two orders of magnitude. Understanding the chemical composition of these Newark Basin core samples is important not only for characterizing materials used for the later lab incubation, but also for gaining a broader understanding of the chemistry of the Newark Basin and profiling the region according to the varying risks associated with a leak of sequestered CO2 to a drinking water aquifer.

Utilization of Fluorescent Microspheres and a Green Fluorescent Protein-Marked Strain for Assessment of Microbiological Contamination of Permafrost and Ground Ice Core Samples from the Canadian High Arctic

PubMed Central

Juck, D. F.; Whissell, G.; Steven, B.; Pollard, W.; McKay, C. P.; Greer, C. W.; Whyte, L. G.

2005-01-01

Fluorescent microspheres were applied in a novel fashion during subsurface drilling of permafrost and ground ice in the Canadian High Arctic to monitor the exogenous microbiological contamination of core samples obtained during the drilling process. Prior to each drill run, a concentrated fluorescent microsphere (0.5-μm diameter) solution was applied to the interior surfaces of the drill bit, core catcher, and core tube and allowed to dry. Macroscopic examination in the field demonstrated reliable transfer of the microspheres to core samples, while detailed microscopic examination revealed penetration levels of less than 1 cm from the core exterior. To monitor for microbial contamination during downstream processing of the permafrost and ground ice cores, a Pseudomonas strain expressing the green fluorescent protein (GFP) was painted on the core exterior prior to processing. Contamination of the processed core interiors with the GFP-expressing strain was not detected by culturing the samples or by PCR to detect the gfp marker gene. These methodologies were quick, were easy to apply, and should help to monitor the exogenous microbiological contamination of pristine permafrost and ground ice samples for downstream culture-dependent and culture-independent microbial analyses. PMID:15691963

Utilization of fluorescent microspheres and a green fluorescent protein-marked strain for assessment of microbiological contamination of permafrost and ground ice core samples from the Canadian High Arctic.

PubMed

Juck, D F; Whissell, G; Steven, B; Pollard, W; McKay, C P; Greer, C W; Whyte, L G

2005-02-01

Fluorescent microspheres were applied in a novel fashion during subsurface drilling of permafrost and ground ice in the Canadian High Arctic to monitor the exogenous microbiological contamination of core samples obtained during the drilling process. Prior to each drill run, a concentrated fluorescent microsphere (0.5-microm diameter) solution was applied to the interior surfaces of the drill bit, core catcher, and core tube and allowed to dry. Macroscopic examination in the field demonstrated reliable transfer of the microspheres to core samples, while detailed microscopic examination revealed penetration levels of less than 1 cm from the core exterior. To monitor for microbial contamination during downstream processing of the permafrost and ground ice cores, a Pseudomonas strain expressing the green fluorescent protein (GFP) was painted on the core exterior prior to processing. Contamination of the processed core interiors with the GFP-expressing strain was not detected by culturing the samples or by PCR to detect the gfp marker gene. These methodologies were quick, were easy to apply, and should help to monitor the exogenous microbiological contamination of pristine permafrost and ground ice samples for downstream culture-dependent and culture-independent microbial analyses.

Ferromagnetic resonance and magnetic studies of cores 60009/60010 and 60003 - Compositional and surface-exposure stratigraphy. [of Apollo deep drill lunar samples

NASA Technical Reports Server (NTRS)

Morris, R. V.; Gose, W. A.

1976-01-01

Ferromagnetic resonance and static magnetic measurements were made on 131 samples from core 60009/60010 and on 40 samples from section 60003 of the Apollo 16 deep drill core. These studies provided depth profiles for composition, in terms of the concentration of FeO, and relative surface exposure age (or maturity), in terms of the values of the specific FMR intensity normalized to the FeO content. For core 60009/60010, the concentration of FeO ranged from about 1.6 wt.% to 5.8 wt.% with a mean value of 4.6 wt.% and the maturity ranged from immature to mature with most of the soils being submature. A systematic decrease in maturity from the lunar surface to a depth of about 12.5 cm was observed in core section 60010. For core section 60003, the concentration of FeO ranged from about 5.2 wt.% to 7.5 wt.% with a mean value of 6.4 wt.% and the maturity ranged from submature to mature with most of the soils being mature.

Penetrator Coring Apparatus for Cometary Surfaces

NASA Technical Reports Server (NTRS)

Braun, David F.; Heinrich, Michael; Ai, Huirong Anita; Ahrens, Thomas J.

2004-01-01

Touch and go impact coring is an attractive technique for sampling cometary nuclei and asteroidal surface on account of the uncertain strength properties and low surface gravities of these objects. Initial coring experiments in low temperature (approx. 153K polycrystalline ice) and porous rock demonstrate that simultaneous with impact coring, measurements of both the penetration strength and constraints on the frictional properties of surface materials can be obtained upon core penetration and core sample extraction. The method of sampling an asteroid, to be deployed, on the now launched MUSES-C mission, employs a small gun device that fires into the asteroid and the resulted impact ejecta is collected for return to Earth. This technique is well suited for initial sampling in a very low gravity environment and deployment depends little on asteroid surface mechanical properties. Since both asteroids and comets are believed to have altered surface properties a simple sampling apparatus that preserves stratigraphic information, such as impact coring is an attractive alternate to impact ejecta collection.

An Improved Extraction and Analysis Technique for Determination of Carbon Monoxide Stable Isotopes and Mixing Ratios from Ice Core and Atmospheric Air Samples.

NASA Astrophysics Data System (ADS)

Place, P., Jr.; Petrenko, V. V.; Vimont, I.

2017-12-01

Carbon Monoxide (CO) is an important atmospheric trace gas that affects the oxidative capacity of the atmosphere and contributes indirectly to anthropogenic radiative forcing. Carbon monoxide stable isotopes can also serve as a tracer for variations in biomass burning, particularly in the preindustrial atmosphere. A good understanding of the past variations in CO mole fractions and isotopic composition can help improve the skill of chemical transport models and constrain biomass burning changes. Ice cores may preserve a record of past atmospheric CO for analysis and interpretation. To this end, a new extraction system has been developed for analysis of stable isotopes (δ13CO and δC18O) of atmospheric carbon monoxide from ice core and atmospheric air samples. This system has been designed to measure relatively small sample sizes (80 cc STP of air) to accommodate the limited availability of ice core samples. Trapped air is extracted from ice core samples via melting in a glass vacuum chamber. This air is expanded into a glass expansion loop and then compressed into the sample loop of a Reducing Gas Detector (Peak Laboratories, Peak Performer 1 RCP) for the CO mole fraction measurement. The remaining sample gas will be expelled from the melt vessel into a larger expansion loop via headspace compression for isotopic analysis. The headspace compression will be accomplished by introduction of clean degassed water into the bottom of the melt vessel. Isotopic analysis of the sample gas is done utilizing the Schütze Reagent to convert the carbon monoxide to carbon dioxide (CO2) which is then measured using continuous-flow isotope ratio mass spectrometry (Elementar Americas, IsoPrime 100). A series of cryogenic traps are used to purify the sample air, capture the converted sample CO2, and cryofocus the sample CO2 prior to injection.

Antarctic ice core samples: culturable bacterial diversity.

PubMed

Shivaji, Sisinthy; Begum, Zareena; Shiva Nageswara Rao, Singireesu Soma; Vishnu Vardhan Reddy, Puram V; Manasa, Poorna; Sailaja, Buddi; Prathiba, Mambatta S; Thamban, Meloth; Krishnan, Kottekkatu P; Singh, Shiv M; Srinivas, Tanuku N R

2013-01-01

Culturable bacterial abundance at 11 different depths of a 50.26 m ice core from the Tallaksenvarden Nunatak, Antarctica, varied from 0.02 to 5.8 × 10(3) CFU ml(-1) of the melt water. A total of 138 bacterial strains were recovered from the 11 different depths of the ice core. Based on 16S rRNA gene sequence analyses, the 138 isolates could be categorized into 25 phylotypes belonging to phyla Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. All isolates had 16S rRNA sequences similar to previously determined sequences (97.2-100%). No correlation was observed in the distribution of the isolates at the various depths either at the phylum, genus or species level. The 25 phylotypes varied in growth temperature range, tolerance to NaCl, growth pH range and ability to produce eight different extracellular enzymes at either 4 or 18 °C. Iso-, anteiso-, unsaturated and saturated fatty acids together constituted a significant proportion of the total fatty acid composition. Copyright © 2012 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Capillary ion chromatography with on-column focusing for ultra-trace analysis of methanesulfonate and inorganic anions in limited volume Antarctic ice core samples.

PubMed

Rodriguez, Estrella Sanz; Poynter, Sam; Curran, Mark; Haddad, Paul R; Shellie, Robert A; Nesterenko, Pavel N; Paull, Brett

2015-08-28

Preservation of ionic species within Antarctic ice yields a unique proxy record of the Earth's climate history. Studies have been focused until now on two proxies: the ionic components of sea salt aerosol and methanesulfonic acid. Measurement of the all of the major ionic species in ice core samples is typically carried out by ion chromatography. Former methods, whilst providing suitable detection limits, have been based upon off-column preconcentration techniques, requiring larger sample volumes, with potential for sample contamination and/or carryover. Here, a new capillary ion chromatography based analytical method has been developed for quantitative analysis of limited volume Antarctic ice core samples. The developed analytical protocol applies capillary ion chromatography (with suppressed conductivity detection) and direct on-column sample injection and focusing, thus eliminating the requirement for off-column sample preconcentration. This limits the total sample volume needed to 300μL per analysis, allowing for triplicate sample analysis with <1mL of sample. This new approach provides a reliable and robust analytical method for the simultaneous determination of organic and inorganic anions, including fluoride, methanesulfonate, chloride, sulfate and nitrate anions. Application to composite ice-core samples is demonstrated, with coupling of the capillary ion chromatograph to high resolution mass spectrometry used to confirm the presence and purity of the observed methanesulfonate peak. Copyright © 2015 Elsevier B.V. All rights reserved.

Acoustic and mechanical properties of Nankai accretionary prism core samples

NASA Astrophysics Data System (ADS)

Raimbourg, Hugues; Hamano, Yozo; Saito, Saneatsu; Kinoshita, Masataka; Kopf, Achim

2011-04-01

We studied undeformed sediment and accreted strata recently recovered by Ocean Drilling Program/Integrated Ocean Drilling Program (ODP/IODP) drilling in Nankai Trough convergent margin to unravel the changes in physical properties from initial deposition to incipient deformation. We have derived acoustic (Vp) and mechanical (uniaxial poroelastic compliance, compaction amplitude) properties of samples from various drill sites along the Muroto (ODP 1173) and Kii transects (IODP C0001, C0002, C0006, and C0007) from isotropic loading tests where confining and pore pressure were independently applied. We quantified the dependence of Vp on both effective (Peff) and confining (Pc) pressure, which can be used to correct atmospheric pressure measurements of Vp. Experimental Vp obtained on core samples extrapolated to in situ conditions are slightly higher than logging-derived velocities, which can be attributed either to velocity dispersion or to the effect of large-scale faults and weak zones on waves with longer wavelength. In the high-porosity (30%-60%) tested sediments, velocities are controlled at first order by porosity and not by lithology, which is in agreement with our static measurements of drained framework incompressibility, much smaller than fluid incompressibility. Rather than framework incompressibility, shear modulus is probably the second-order control on Vp, accounting for most of the difference between actual Vp and the prediction by Wood's (1941) suspension model. We also quantified the mechanical state of Nankai samples in terms of anisotropy, diagenesis, and consolidation. Both acoustic and mechanical parameters reveal similar values in vertical and horizontal directions, attesting to the very low anisotropy of the tested material. When considering the porous samples of the Upper Shikoku Basin sediments (Site 1173) as examples of diagenetically cemented material, several mechanical and acoustic attributes appeared as reliable experimental indicators of

Drill hole logging with infrared spectroscopy

USGS Publications Warehouse

Calvin, W.M.; Solum, J.G.

2005-01-01

Infrared spectroscopy has been used to identify rocks and minerals for over 40 years. The technique is sensitive to primary silicates as well as alteration products. Minerals can be uniquely identified based on multiple absorption features at wavelengths from the visible to the thermal infrared. We are currently establishing methods and protocols in order to use the technique for rapid assessment of downhole lithology on samples obtained during drilling operations. Initial work performed includes spectral analysis of chip cuttings and core sections from drill sites around Desert Peak, NV. In this paper, we report on a survey of 10,000 feet of drill cuttings, at 100 foot intervals, from the San Andreas Fault Observatory at Depth (SAFOD). Data from Blue Mountain geothermal wells will also be acquired. We will describe the utility of the technique for rapid assessment of lithologic and mineralogic discrimination.

Monitoring microearthquakes with the San Andreas fault observatory at depth

USGS Publications Warehouse

Oye, V.; Ellsworth, W.L.

2007-01-01

In 2005, the San Andreas Fault Observatory at Depth (SAFOD) was drilled through the San Andreas Fault zone at a depth of about 3.1 km. The borehole has subsequently been instrumented with high-frequency geophones in order to better constrain locations and source processes of nearby microearthquakes that will be targeted in the upcoming phase of SAFOD. The microseismic monitoring software MIMO, developed by NORSAR, has been installed at SAFOD to provide near-real time locations and magnitude estimates using the high sampling rate (4000 Hz) waveform data. To improve the detection and location accuracy, we incorporate data from the nearby, shallow borehole (???250 m) seismometers of the High Resolution Seismic Network (HRSN). The event association algorithm of the MIMO software incorporates HRSN detections provided by the USGS real time earthworm software. The concept of the new event association is based on the generalized beam forming, primarily used in array seismology. The method requires the pre-computation of theoretical travel times in a 3D grid of potential microearthquake locations to the seismometers of the current station network. By minimizing the differences between theoretical and observed detection times an event is associated and the location accuracy is significantly improved.

Measuring of electrical changes induced by in situ combustion through flow-through electrodes in a laboratory sample of core material

DOEpatents

Lee, D.O.; Montoya, P.C.; Wayland, J.R. Jr.

1986-12-09

Method and apparatus are provided for obtaining accurate dynamic measurements for passage of phase fronts through a core sample in a test fixture. Flow-through grid structures are provided for electrodes to permit data to be obtained before, during and after passage of a front there through. Such electrodes are incorporated in a test apparatus for obtaining electrical characteristics of the core sample. With the inventive structure a method is provided for measurement of instabilities in a phase front progressing through the medium. Availability of accurate dynamic data representing parameters descriptive of material characteristics before, during and after passage of a front provides a more efficient method for enhanced recovery of oil using a fire flood technique. 12 figs.

Measuring of electrical changes induced by in situ combustion through flow-through electrodes in a laboratory sample of core material

DOEpatents

Lee, David O.; Montoya, Paul C.; Wayland, Jr., James R.

1986-01-01

Method and apparatus are provided for obtaining accurate dynamic measurements for passage of phase fronts through a core sample in a test fixture. Flow-through grid structures are provided for electrodes to permit data to be obtained before, during and after passage of a front therethrough. Such electrodes are incorporated in a test apparatus for obtaining electrical characteristics of the core sample. With the inventive structure a method is provided for measurement of instabilities in a phase front progressing through the medium. Availability of accurate dynamic data representing parameters descriptive of material characteristics before, during and after passage of a front provides a more efficient method for enhanced recovery of oil using a fire flood technique.

GenoCore: A simple and fast algorithm for core subset selection from large genotype datasets.

PubMed

Jeong, Seongmun; Kim, Jae-Yoon; Jeong, Soon-Chun; Kang, Sung-Taeg; Moon, Jung-Kyung; Kim, Namshin

2017-01-01

Selecting core subsets from plant genotype datasets is important for enhancing cost-effectiveness and to shorten the time required for analyses of genome-wide association studies (GWAS), and genomics-assisted breeding of crop species, etc. Recently, a large number of genetic markers (>100,000 single nucleotide polymorphisms) have been identified from high-density single nucleotide polymorphism (SNP) arrays and next-generation sequencing (NGS) data. However, there is no software available for picking out the efficient and consistent core subset from such a huge dataset. It is necessary to develop software that can extract genetically important samples in a population with coherence. We here present a new program, GenoCore, which can find quickly and efficiently the core subset representing the entire population. We introduce simple measures of coverage and diversity scores, which reflect genotype errors and genetic variations, and can help to select a sample rapidly and accurately for crop genotype dataset. Comparison of our method to other core collection software using example datasets are performed to validate the performance according to genetic distance, diversity, coverage, required system resources, and the number of selected samples. GenoCore selects the smallest, most consistent, and most representative core collection from all samples, using less memory with more efficient scores, and shows greater genetic coverage compared to the other software tested. GenoCore was written in R language, and can be accessed online with an example dataset and test results at https://github.com/lovemun/Genocore.

Trace-element analyses of core samples from the 1967-1988 drillings of Kilauea Iki lava lake, Hawaii

USGS Publications Warehouse

Helz, Rosalind Tuthill

2012-01-01

This report presents previously unpublished analyses of trace elements in drill core samples from Kilauea Iki lava lake and from the 1959 eruption that fed the lava lake. The two types of data presented were obtained by instrumental neutron-activation analysis (INAA) and energy-dispersive X-ray fluorescence analysis (EDXRF). The analyses were performed in U.S. Geological Survey (USGS) laboratories from 1989 to 1994. This report contains 93 INAA analyses on 84 samples and 68 EDXRF analyses on 68 samples. The purpose of the study was to document trace-element variation during chemical differentiation, especially during the closed-system differentiation of Kilauea Iki lava lake.

Imaging Stress Transients and Fault Zone Processes with Crosswell Continuous Active-Source Seismic Monitoring at the San Andreas Fault Observatory at Depth

NASA Astrophysics Data System (ADS)

Niu, F.; Taira, T.; Daley, T. M.; Marchesini, P.; Robertson, M.; Wood, T.

2017-12-01

Recent field and laboratory experiments identify seismic velocity changes preceding microearthquakes and rock failure (Niu et al., 2008, Nature; Scuderi et al., 2016, NatureGeo), which indicates that a continuous monitoring of seismic velocity might provide a mean of understanding of the earthquake nucleation process. Crosswell Continuous Active-Source Seismic Monitoring (CASSM) using borehole sources and sensors has proven to be an effective tool for measurements of seismic velocity and its temporal variation at seismogenic depth (Silver, et al, 2007, BSSA; Daley, et al, 2007, Geophysics). To expand current efforts on the CASSM development, in June 2017 we have begun to conduct a year-long CASSM field experiment at the San Andreas Fault Observatory at Depth (SAFOD) in which the preceding field experiment detected the two sudden velocity reductions approximately 10 and 2 hours before microearthquakes (Niu et al., 2008, Nature). We installed a piezoelectric source and a three-component accelerometer at the SAFOD pilot and main holes ( 1 km depth) respectively. A seismic pulse was fired from the piezoelectric source four times per second. Each waveform was recorded 150-ms-long data with a sampling rate of 48 kHz. During this one-year experiment, we expect to have 10-15 microearthquakes (magnitude 1-3) occurring near the SAFOD site, and the data collected from the new experiment would allow us to further explore a relation between velocity changes and the Parkfield seismicity. Additionally, the year-long data provide a unique opportunity to study long-term velocity changes that might be related to seasonal stress variations at Parkfield (Johnson et al., 2017, Science). We will report on initial results of the SAFOD CASSM experiment and operational experiences of the CASSM development.

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

Non-destructive Analysis of Oil-Contaminated Soil Core Samples by X-ray Computed Tomography and Low-Field Nuclear Magnetic Resonance Relaxometry: a Case Study

PubMed Central

Mitsuhata, Yuji; Nishiwaki, Junko; Kawabe, Yoshishige; Utsuzawa, Shin; Jinguuji, Motoharu

2010-01-01

Non-destructive measurements of contaminated soil core samples are desirable prior to destructive measurements because they allow obtaining gross information from the core samples without touching harmful chemical species. Medical X-ray computed tomography (CT) and time-domain low-field nuclear magnetic resonance (NMR) relaxometry were applied to non-destructive measurements of sandy soil core samples from a real site contaminated with heavy oil. The medical CT visualized the spatial distribution of the bulk density averaged over the voxel of 0.31 × 0.31 × 2 mm3. The obtained CT images clearly showed an increase in the bulk density with increasing depth. Coupled analysis with in situ time-domain reflectometry logging suggests that this increase is derived from an increase in the water volume fraction of soils with depth (i.e., unsaturated to saturated transition). This was confirmed by supplementary analysis using high-resolution micro-focus X-ray CT at a resolution of ∼10 μm, which directly imaged the increase in pore water with depth. NMR transverse relaxation waveforms of protons were acquired non-destructively at 2.7 MHz by the Carr–Purcell–Meiboom–Gill (CPMG) pulse sequence. The nature of viscous petroleum molecules having short transverse relaxation times (T2) compared to water molecules enabled us to distinguish the water-saturated portion from the oil-contaminated portion in the core sample using an M0–T2 plot, where M0 is the initial amplitude of the CPMG signal. The present study demonstrates that non-destructive core measurements by medical X-ray CT and low-field NMR provide information on the groundwater saturation level and oil-contaminated intervals, which is useful for constructing an adequate plan for subsequent destructive laboratory measurements of cores. PMID:21258437

Student Wellbeing at a University in Post-Apartheid South Africa: A Comparison with a British University Sample Using the GP-CORE Measure

ERIC Educational Resources Information Center

Young, Charles; Campbell, Megan

2014-01-01

This article provides GP-CORE norms for a South African university sample, which are compared to published data obtained from a United Kingdom university sample. The measure appears to be both reliable and valid for this multilingual and multicultural South African sample. The profiles of the psychological distress reported by white South African…

Characterization of organic material in ice core samples from North America, Greenland, and Antarctica using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry

NASA Astrophysics Data System (ADS)

Catanzano, V.; Grannas, A. M.; Sleighter, R. L.; Hatcher, P. G.

2013-12-01

Historically, it has been an analytical challenge to detect and identify the organic components present in ice cores, due to the low abundance of organic carbon. In order to detect and characterize the small amounts of organic matter in ice cores, ultra high resolution instrumentation is required. Here we report the use of ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry, coupled with electrospray ionization, to identify the molecular formulas and compound classes of organic matter in both modern and ancient ice core and glacial samples from Wyoming, Greenland, and Antarctica. A suite of 21 samples were analyzed and thousands of distinct molecular species were identified in each sample, providing clues to the nature and sources of organic matter in these regions. Major biochemical classes of compounds were detected such as lignins, tannins, carbohydrates, proteins, lipids, unsaturated hydrocarbons, and condensed aromatic compounds. We will compare the nature of the organic matter present in the samples in order to determine the differences in dominant organic compound classes and in heteroatom (nitrogen and sulfur) abundance. By analyzing these differences, it is possible to investigate the historical patterns of organic matter deposition/source, and begin to investigate the influence of climate change, volcanism, and onset of the industrial revolution on the nature of organic matter preserved in ice cores.

The factor structure and psychometric properties of the Clinical Outcomes in Routine Evaluation – Outcome Measure (CORE-OM) in Norwegian clinical and non-clinical samples

PubMed Central

2013-01-01

Background The Clinical Outcomes in Routine Evaluation - Outcome Measure (CORE-OM) is a 34-item instrument developed to monitor clinically significant change in out-patients. The CORE-OM covers four domains: well-being, problems/symptoms, functioning and risk, and sums up in two total scores: the mean of All items, and the mean of All non-risk items. The aim of this study was to examine the psychometric properties of the Norwegian translation of the CORE-OM. Methods A clinical sample of 527 out-patients from North Norwegian specialist psychiatric services, and a non-clinical sample of 464 persons were obtained. The non-clinical sample was a convenience sample consisting of friends and family of health personnel, and of students of medicine and clinical psychology. Students also reported psychological stress. Exploratory factor analysis (EFA) was employed in half the clinical sample. Confirmatory (CFA) factor analyses modelling the theoretical sub-domains were performed in the remaining half of the clinical sample. Internal consistency, means, and gender and age differences were studied by comparing the clinical and non-clinical samples. Stability, effect of language (Norwegian versus English), and of psychological stress was studied in the sub-sample of students. Finally, cut-off scores were calculated, and distributions of scores were compared between clinical and non-clinical samples, and between students reporting stress or no stress. Results The results indicate that the CORE-OM both measures general (g) psychological distress and sub-domains, of which risk of harm separates most clearly from the g factor. Internal consistency, stability and cut-off scores compared well with the original English version. No, or only negligible, language effects were found. Gender differences were only found for the well-being domain in the non-clinical sample and for the risk domain in the clinical sample. Current patient status explained differences between clinical and non

Rolling-Tooth Core Breakoff and Retention Mechanism

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Bickler, Donald B.; Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Hudson, Nicolas H.

2011-01-01

Sampling cores requires the controlled breakoff of the core at a known location with respect to the drill end. An additional problem is designing a mechanism that can be implemented at a small scale that is robust and versatile enough to be used for a variety of core samples. This design consists of a set of tubes (a drill tube and an inner tube) and a rolling element (rolling tooth). An additional tube can be used as a sample tube. The drill tube and the inner tube have longitudinal holes with the axes offset from the axis of each tube. The two eccentricities are equal. The inner tube fits inside the drill tube, and the sample tube fits inside the inner tube. While drilling, the two tubes are positioned relative to each other such that the sample tube is aligned with the drill tube axis and core. The drill tube includes teeth and flutes for cuttings removal. The inner tube includes, at the base, the rolling element implemented as a wheel on a shaft in an eccentric slot. An additional slot in the inner tube and a pin in the drill tube limit the relative motion of the two tubes. While drilling, the drill assembly rotates relative to the core and forces the rolling tooth to stay hidden in the slot along the inner tube wall. When the drilling depth has been reached, the drill bit assembly is rotated in the opposite direction, and the rolling tooth is engaged and penetrates into the core. Depending on the strength of the created core, the rolling tooth can score, lock the inner tube relative to the core, start the eccentric motion of the inner tube, and break the core. The tooth and the relative position of the two tubes can act as a core catcher or core-retention mechanism as well. The design was made to fit the core and hole parameters produced by an existing bit; the parts were fabricated and a series of demonstration tests were performed. This invention is potentially applicable to sample return and in situ missions to planets such as Mars and Venus, to moons such

The Importance of Mars Samples in Constraining the Geological and Geophysical Processes on Mars and the Nature of its Crust, Mantle, and Core

NASA Astrophysics Data System (ADS)

iMOST Team; Herd, C. D. K.; Ammannito, E.; Anand, M.; Debaille, V.; Hallis, L. J.; McCubbin, F. M.; Schmitz, N.; Usui, T.; Weiss, B. P.; Altieri, F.; Amelin, Y.; Beaty, D. W.; Benning, L. G.; Bishop, J. L.; Borg, L. E.; Boucher, D.; Brucato, J. R.; Busemann, H.; Campbell, K. A.; Carrier, B. L.; Czaja, A. D.; Des Marais, D. J.; Dixon, M.; Ehlmann, B. L.; Farmer, J. D.; Fernandez-Remolar, D. C.; Fogarty, J.; Glavin, D. P.; Goreva, Y. S.; Grady, M. M.; Harrington, A. D.; Hausrath, E. M.; Horgan, B.; Humayun, M.; Kleine, T.; Kleinhenz, J.; Mangold, N.; Mackelprang, R.; Mayhew, L. E.; McCoy, J. T.; McLennan, S. M.; McSween, H. Y.; Moser, D. E.; Moynier, F.; Mustard, J. F.; Niles, P. B.; Ori, G. G.; Raulin, F.; Rettberg, P.; Rucker, M. A.; Sefton-Nash, E.; Sephton, M. A.; Shaheen, R.; Shuster, D. L.; Siljestrom, S.; Smith, C. L.; Spry, J. A.; Steele, A.; Swindle, T. D.; ten Kate, I. L.; Tosca, N. J.; Van Kranendonk, M. J.; Wadhwa, M.; Werner, S. C.; Westall, F.; Wheeler, R. M.; Zipfel, J.; Zorzano, M. P.

2018-04-01

We present the main sample types from any potential Mars Sample Return landing site that would be required to constrain the geological and geophysical processes on Mars, including the origin and nature of its crust, mantle, and core.

Lightweight Low Force Rotary Percussive Coring Tool for Planetary Applications

NASA Technical Reports Server (NTRS)

Hironaka, Ross; Stanley, Scott

2010-01-01

A prototype low-force rotary-percussive rock coring tool for use in acquiring samples for geological surveys in future planetary missions was developed. The coring tool could eventually enable a lightweight robotic system to operate from a relatively small (less than 200 kg) mobile or fixed platform to acquire and cache Mars or other planetary rock samples for eventual return to Earth for analysis. To gain insight needed to design an integrated coring tool, the coring ability of commercially available coring bits was evaluated for effectiveness of varying key parameters: weight-on-bit, rotation speed, percussive rate and force. Trade studies were performed for different methods of breaking a core at its base and for retaining the core in a sleeve to facilitate sample transfer. This led to a custom coring tool design which incorporated coring, core breakage, core retention, and core extraction functions. The coring tool was tested on several types of rock and demonstrated the overall feasibility of this approach for robotic rock sample acquisition.

High-resolution delineation of chlorinated volatile organic compounds in a dipping, fractured mudstone: Depth- and strata-dependent spatial variability from rock-core sampling

NASA Astrophysics Data System (ADS)

Goode, Daniel J.; Imbrigiotta, Thomas E.; Lacombe, Pierre J.

2014-12-01

Synthesis of rock-core sampling and chlorinated volatile organic compound (CVOC) analysis at five coreholes, with hydraulic and water-quality monitoring and a detailed hydrogeologic framework, was used to characterize the fine-scale distribution of CVOCs in dipping, fractured mudstones of the Lockatong Formation of Triassic age, of the Newark Basin in West Trenton, New Jersey. From these results, a refined conceptual model for more than 55 years of migration of CVOCs and depth- and strata-dependent rock-matrix contamination was developed. Industrial use of trichloroethene (TCE) at the former Naval Air Warfare Center (NAWC) from 1953 to 1995 resulted in dense non-aqueous phase liquid (DNAPL) TCE and dissolved TCE and related breakdown products, including other CVOCs, in underlying mudstones. Shallow highly weathered and fractured strata overlie unweathered, gently dipping, fractured strata that become progressively less fractured with depth. The unweathered lithology includes black highly fractured (fissile) carbon-rich strata, gray mildly fractured thinly layered (laminated) strata, and light-gray weakly fractured massive strata. CVOC concentrations in water samples pumped from the shallow weathered and highly fractured strata remain elevated near residual DNAPL TCE, but dilution by uncontaminated recharge, and other natural and engineered attenuation processes, have substantially reduced concentrations along flow paths removed from sources and residual DNAPL. CVOCs also were detected in most rock-core samples in source areas in shallow wells. In many locations, lower aqueous concentrations, compared to rock core concentrations, suggest that CVOCs are presently back-diffusing from the rock matrix. Below the weathered and highly fractured strata, and to depths of at least 50 meters (m), groundwater flow and contaminant transport is primarily in bedding-plane-oriented fractures in thin fissile high-carbon strata, and in fractured, laminated strata of the gently

High-resolution delineation of chlorinated volatile organic compounds in a dipping, fractured mudstone: depth- and strata-dependent spatial variability from rock-core sampling

USGS Publications Warehouse

Goode, Daniel J.; Imbrigiotta, Thomas E.; Lacombe, Pierre J.

2014-01-01

Synthesis of rock-core sampling and chlorinated volatile organic compound (CVOC) analysis at five coreholes, with hydraulic and water-quality monitoring and a detailed hydrogeologic framework, was used to characterize the fine-scale distribution of CVOCs in dipping, fractured mudstones of the Lockatong Formation of Triassic age, of the Newark Basin in West Trenton, New Jersey. From these results, a refined conceptual model for more than 55 years of migration of CVOCs and depth- and strata-dependent rock-matrix contamination was developed. Industrial use of trichloroethene (TCE) at the former Naval Air Warfare Center (NAWC) from 1953 to 1995 resulted in dense non-aqueous phase liquid (DNAPL) TCE and dissolved TCE and related breakdown products, including other CVOCs, in underlying mudstones. Shallow highly weathered and fractured strata overlie unweathered, gently dipping, fractured strata that become progressively less fractured with depth. The unweathered lithology includes black highly fractured (fissile) carbon-rich strata, gray mildly fractured thinly layered (laminated) strata, and light-gray weakly fractured massive strata. CVOC concentrations in water samples pumped from the shallow weathered and highly fractured strata remain elevated near residual DNAPL TCE, but dilution by uncontaminated recharge, and other natural and engineered attenuation processes, have substantially reduced concentrations along flow paths removed from sources and residual DNAPL. CVOCs also were detected in most rock-core samples in source areas in shallow wells. In many locations, lower aqueous concentrations, compared to rock core concentrations, suggest that CVOCs are presently back-diffusing from the rock matrix. Below the weathered and highly fractured strata, and to depths of at least 50 meters (m), groundwater flow and contaminant transport is primarily in bedding-plane-oriented fractures in thin fissile high-carbon strata, and in fractured, laminated strata of the gently

Analytical Results for 42 Fluvial Tailings Cores and 7 Stream Sediment Samples from High Ore Creek, Northern Jefferson County, Montana

USGS Publications Warehouse

Fey, David L.; Church, Stan E.

1998-01-01

Metal-mining related wastes in the Boulder River basin study area in northern Jefferson County, Montana have been implicated in their detrimental effects on water quality with regard to acid-generation and toxic-metal solubility. Sediments, fluvial tailings and water from High Ore Creek have been identified as significant contributors to water quality degradation of the Boulder River below Basin, Montana. A study of 42 fluvial tailings cores and 7 stream sediments from High Ore Creek was undertaken to determine the concentrations of environmentally sensitive elements (i.e. Ag, As, Cd, Cu, Pb, Zn) present in these materials, and the mineral phases containing those elements. Two sites of fluvial deposition of mine-waste contaminated sediment on upper High Ore Creek were sampled using a one-inch soil probe. Forty-two core samples were taken producing 247 subsamples. The samples were analyzed by ICP-AES (inductively coupled-plasma atomic emission spectroscopy) using a total mixed-acid digestion. Results of the core analyses show that the elements described above are present at very high concentrations (to 22,000 ppm As, to 460 ppm Ag, to 900 ppm Cd, 4,300 ppm Cu, 46,000ppm Pb, and 50,000 ppm Zn). Seven stream-sediment samples were also analyzed by ICP-AES for total element content and for leachable element content. Results show that the sediment of High Ore Creek has elevated levels of ore-related metals throughout its length, down to the confluence with the Boulder River, and that the metals are, to a significant degree, contained in the leachable phase, namely the hydrous amorphous iron- and manganese-hydroxide coatings on detrital sediment particles.

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

The ICDP project PASADO aims to develop a detailed paleoclimatic record for the southern part of the South American continent from sediments of Laguna Potrok Aike (51°58'S, 70°23'W), situated in the Patagonian steppe east of the Andean cordillera and north of the Street of Magellan. The precursor project SALSA recovered the Holocene and Late Glacial sediment infill of Laguna Potrok Aike and developed the environmental history of the semi-arid Patagonian steppe by a consequent interdisciplinary multi-proxy approach (e.g. Haberzettl et al., 2007). From September to November 2008 the ICDP deep drilling took place and successfully recovered in total 510 m of sediments from two sites resulting in a composite depth of 106 m for the selected main study Site 2. A preliminary age model places the record within the last 50.000 years. During the drilling campaign, the core catcher content of each drilled core run (3 m) was taken as separate sample to be shared and distributed between involved laboratories long before the main sampling party. A total of 70 core catcher samples describe the sediments of Site 2 and will form the base for more detailed investigations on the palaeoclimatic history of Patagonia. We here report on the organic carbon and nitrogen isotope composition of bulk sediment and plant debris of the core catcher samples. Similar investigations were performed for Holocene and Late Glacial sediments of Laguna Potrok Aike revealing insights into the organic matter dynamics of the lake and its catchment as well as into climatically induced hydrological variations with related lake level fluctuations (Mayr et al., 2009). The carbon and nitrogen content of the core catcher fine sediment fraction (<200 µm) is low to very low (around 1 % and 0.1 %, respectively) and requires particular attention in isotope analysis. The carbon isotope composition shows comparably little variation around a value of -26.0 per mil. The positive values of the Holocene and the Late

a Mineralogical Analysis of Hspdp Core Samples from the Northern Awash Pliocene Hadar Formation, Ethiopia: the tale of AN East African Paleolake

NASA Astrophysics Data System (ADS)

Davis, D. M.; Deocampo, D.; Rabideaux, N. M.; Campisano, C. J.

2017-12-01

The Northern Awash Valley is located in the southwestern portion of the Afar Depression in Ethiopia. During the 2014 field season, two core sites were drilled as part of the Hominin Sites and Paleolakes Drilling Project (HSPDP), recovering a total of 600 m of sediment from both localities (NAO and NAW). Mineralogical analyses of the bulk sediments and clays from the Hadar Formation have helped to begin constructing a more complete picture of the paleoenvironmental conditions of the Northern Awash during the Pliocene. This work is an attempt to begin to answer the questions about salinity/alkalinity of Hadar Paleolake as well as its sulfur content. The two sites, NAW and NAO, are about 3 kilometers apart and presumably part of the same paleolake basin. The data has shown that this area was much more humid during the Pliocene than it is today and that most of the minerals in the paleolake basin are detrital, save for calcite, Mg-calcite, gypsum, pyrite, and a few zeolites. 060 analyses of the clays in the cores show that the lake was a freshwater lake three million years ago, up until its eventual evaporation. Interestingly, the lack of trioctahedral clays is an indication that the lake water did not become highly saline and alkaline during its evaporation. An interesting contrast between the two cores shows that NAO contains gypsum, but so far, no pyrite. NAW, on the other hand, contains both pyrite and gypsum. The pyrite in NAW is mostly at the bottom of the core, whereas, the gypsum is intermittent throughout the core and much more sparse toward the bottom. This line of evidence suggests that the two sites within the lake may have experienced different redox conditions. It may be that the NAO core was sampled in a shallower part of the lake whereas the NAW core sampled a deeper section.

Cores to the rescue: how old cores enable new science

NASA Astrophysics Data System (ADS)

Ito, E.; Noren, A. J.; Brady, K.

2016-12-01

The value of archiving scientific specimens and collections for the purpose of enabling further research using new analytical techniques, resolving conflicting results, or repurposing them for entirely new research, is often discussed in abstract terms. We all agree that samples with adequate metadata ought to be archived systematically for easy access, for a long time and stored under optimal conditions. And yet, as storage space fills, there is a temptation to cull the collection, or when a researcher retires, to discard the collection unless the researcher manages to make his or her own arrangement for the collection to be accessioned elsewhere. Nobody has done anything with these samples in over 20 years! Who would want them? It turns out that plenty of us do want them, if we know how to find them and if they have sufficient metadata to assess past work and suitability for new analyses. The LacCore collection holds over 33 km of core from >6700 sites in diverse geographic locations worldwide with samples collected as early as 1950s. From these materials, there are many examples to illustrate the scientific value of archiving geologic samples. One example that benefitted Ito personally were cores from Lakes Mirabad and Zeribar, Iran, acquired in 1963 by Herb Wright and his associates. Several doctoral and postdoctoral students generated and published paleoecological reconstructions based on cladocerans, diatoms, pollen or plant macrofossils, mostly between 1963 and 1967. The cores were resampled in 1990s by a student being jointly advised by Wright and Ito for oxygen isotope analysis of endogenic calcite. The results were profitably compared with pollen and the results published in 2001 and 2006. From 1979 until very recently, visiting Iran for fieldwork was not pallowed for US scientists. Other examples will be given to further illustrate the power of archived samples to advance science.

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.

Determination of three-dimensional stress orientations in the Wenchuan earthquake Fault Scientific Drilling (WFSD) hole-1: A preliminary result by anelastic strain recovery measurements of core samples

NASA Astrophysics Data System (ADS)

Cui, J.; Lin, W.; Wang, L.; Tang, Z.; Sun, D.; Gao, L.; Wang, W.

2010-12-01

A great and destructive earthquake (Ms 8.0; Mw 7.9), Wunchuan earthquake struck on the Longmen Shan foreland trust zone in Sichuan province, China on 12 May 2008 (Xu et al., 2008; Episodes, Vol.31, pp.291-301). As a rapid response scientific drilling project, Wenchuan earthquake Fault Scientific Drilling (WFSD) started on 6 November 2008 shorter than a half of year from the date of earthquake main shock. The first pilot borehole (hole-1) has been drilled to the target depth (measured depth 1201 m MD, vertical depth 1179 m) at Hongkou, Dujianyan, Sichuan and passed through the main fault of the earthquake around 589 m MD. We are trying to determine three dimensional in-situ stress states in the WFSD boreholes by a core-based method, anelastic strain recovery (ASR) method (Lin et al., 2006; Tectonophysics, Vol4.26, pp.221-238). This method has been applied in several scientific drilling projects (TCDP: Lin et al., 2007; TAO, Vol.18, pp.379-393; NanTtoSEIZE: Byrne et al., 2009; GRL, Vol.36, L23310). These applications confirm the validity of using the ASR technique in determining in situ stresses by using drilled cores. We collected total 15 core samples in a depth range from 340 m MD to 1180 m MD, approximately for ASR measurements. Anelastic normal strains, measured every ten minutes in nine directions, including six independent directions, were used to calculate the anelastic strain tensors. The data of the ASR tests conducted at hole-1 is still undergoing analysis. As a tentative perspective, more than 10 core samples showed coherent strain recovery over one - two weeks. However, 2 or 3 core samples cannot be re-orientated to the global system. It means that we cannot rink the stress orientation determined by the core samples to geological structure. Unfortunately, a few core samples showed irregular strain recovery and were not analyzed further. The preliminary results of ASR tests at hole-1 show the stress orientations and stress regime changes a lot with the

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.

The PASADO core processing strategy — A proposed new protocol for sediment core treatment in multidisciplinary lake drilling projects

NASA Astrophysics Data System (ADS)

Ohlendorf, Christian; Gebhardt, Catalina; Hahn, Annette; Kliem, Pierre; Zolitschka, Bernd

2011-07-01

Using the ICDP (International Continental Scientific Drilling Program) deep lake drilling expedition no. 5022 as an example, we describe core processing and sampling procedures as well as new tools developed for subsampling. A manual core splitter is presented that is (1) mobile, (2) able to cut plastic core liners lengthwise without producing swarf of liner material and (3) consists of off-the-shelf components. In order to improve the sampling of sediment cores, a new device, the core sampling assembly (CSA), was developed that meets the following targets: (1) the partitioning of the sediment into discs of equal thickness is fast and precise, (2) disturbed sediment at the inner surface of the liner is discarded during this sampling process, (3) usage of the available sediment is optimised, (4) subsamples are volumetric and oriented, and (5) identical subsamples are taken. The CSA can be applied to D-shaped split sediment cores of any diameter and consists of a divider and a D-shaped scoop. The sampling plan applied for ICDP expedition 5022 is illustrated and may be used as a guideline for planning the efficient partitioning of sediment amongst different lake research groups involved in multidisciplinary projects. For every subsample, the use of quality flags is suggested (1) to document the sample condition, (2) to give a first sediment classification and (3) to guarantee a precise adjustment of logging and scanning data with data determined on individual samples. Based on this, we propose a protocol that might be applied across lake drilling projects in order to facilitate planning and documentation of sampling campaigns and to ensure a better comparability of results.

A radiographic scanning technique for cores

USGS Publications Warehouse

Hill, G.W.; Dorsey, M.E.; Woods, J.C.; Miller, R.J.

1979-01-01

A radiographic scanning technique (RST) can produce single continuous radiographs of cores or core sections up to 1.5 m long and up to 30 cm wide. Changing a portable industrial X-ray unit from the normal still-shot mode to a scanning mode requires simple, inexpensive, easily constructed, and highly durable equipment. Additional components include a conveyor system, antiscatter cylinder-diaphragm, adjustable sample platform, developing tanks, and a contact printer. Complete cores, half cores, sample slabs or peels may be scanned. Converting the X-ray unit from one mode to another is easy and can be accomplished without the use of special tools. RST provides the investigator with a convenient, continuous, high quality radiograph, saves time and money, and decreases the number of times cores have to be handled. ?? 1979.

Historic CH4 Records from Antarctic and Greenland Ice Cores, Antarctic Firn Data, and Archived Air Samples from Cape Grim, Tasmania

DOE Data Explorer

Etheridge, D. M. [Division of Atmospheric Research, CSIRO, Aspendale, Victoria, Australia; Steele, L. P. [Division of Atmospheric Research, CSIRO, Aspendale, Victoria, Australia; Francey, R. J. [Division of Atmospheric Research, CSIRO, Aspendale, Victoria, Australia; Langenfelds, R. L. [Division of Atmospheric Research, CSIRO, Aspendale, Victoria, Australia

2002-01-01

The Antarctic CH4 records presented here are derived from three ice cores obtained at Law Dome, East Antarctica (66°44'S, 112°50'E, 1390 meters above mean sea level). Law Dome has many qualities of an ideal ice core site for the reconstruction of past concentrations of atmospheric gases; these qualities include: negligible melting of the ice sheet surface, low concentrations of impurities, regular stratigraphic layering undisturbed by wind stress at the surface or differential ice flow at depth, and a high snow accumulation rate. Further details on the site, drilling, and cores are provided by Etheridge et al. (1998), Etheridge et al. (1996), Etheridge and Wookey (1989), and Morgan et al. (1997). The two Greenland ice cores are from the Summit region (72°34' N, 37°37' W, 3200 meters above mean sea level). Lower snow accumulation rate there results in lower air-age resolution, and measurements presented here cover only the pre-industrial period (until 1885). More details about these measurements are presented in Etheridge et al. (1998). Additionally, this site contains firn data from Core DE08-2, and archived air samples from Cape Grim, Tasmania, for comparison.

Micro coring apparatus

NASA Technical Reports Server (NTRS)

Collins, David; Brooks, Marshall; Chen, Paul; Dwelle, Paul; Fischer, Ben

1989-01-01

A micro-coring apparatus for lunar exploration applications, that is compatible with the other components of the Walking Mobile Platform, was designed. The primary purpose of core sampling is to gain an understanding of the geological composition and properties of the prescribed environment. This procedure has been used extensively for Earth studies and in limited applications during lunar explorations. The corer is described and analyzed for effectiveness.

Analysis and Modeling of the Wavefield Generated by Explosions at the San Andreas Fault Observatory at Depth

DTIC Science & Technology

2010-09-01

method to ~ 4 Hz wave propagation using SAFOD borehole seismometers and the Parkfield Array Seismic Observatory (PASO) array (Thurber et al., 2004...limitations in mind, we apply our method to ~ 4 Hz wave propagation using SAFOD borehole seismometers and the Parkfield Array Seismic Observatory (PASO...Proposal No. BAA09-69 ABSTRACT Surface array and deep borehole recordings of chemical explosions in the near-source (0-20 km) region are studied to

Apollo rocks, fines and soil cores

NASA Astrophysics Data System (ADS)

Allton, J.; Bevill, T.

Apollo rocks and soils not only established basic lunar properties and ground truth for global remote sensing, they also provided important lessons for planetary protection (Adv. Space Res ., 1998, v. 22, no. 3 pp. 373-382). The six Apollo missions returned 2196 samples weighing 381.7 kg, comprised of rocks, fines, soil cores and 2 gas samples. By examining which samples were allocated for scientific investigations, information was obtained on usefulness of sampling strategy, sampling devices and containers, sample types and diversity, and on size of sample needed by various disciplines. Diversity was increased by using rakes to gather small rocks on the Moon and by removing fragments >1 mm from soils by sieving in the laboratory. Breccias and soil cores are diverse internally. Per unit weight these samples were more often allocated for research. Apollo investigators became adept at wringing information from very small sample sizes. By pushing the analytical limits, the main concern was adequate size for representative sampling. Typical allocations for trace element analyses were 750 mg for rocks, 300 mg for fines and 70 mg for core subsamples. Age-dating and isotope systematics allocations were typically 1 g for rocks and fines, but only 10% of that amount for core depth subsamples. Historically, allocations for organics and microbiology were 4 g (10% for cores). Modern allocations for biomarker detection are 100mg. Other disciplines supported have been cosmogenic nuclides, rock and soil petrology, sedimentary volatiles, reflectance, magnetics, and biohazard studies . Highly applicable to future sample return missions was the Apollo experience with organic contamination, estimated to be from 1 to 5 ng/g sample for Apollo 11 (Simonheit &Flory, 1970; Apollo 11, 12 &13 Organic contamination Monitoring History, U.C. Berkeley; Burlingame et al., 1970, Apollo 11 LSC , pp. 1779-1792). Eleven sources of contaminants, of which 7 are applicable to robotic missions, were

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/.

The use of mini-samples in palaeomagnetism

NASA Astrophysics Data System (ADS)

Böhnel, Harald; Michalk, Daniel; Nowaczyk, Norbert; Naranjo, Gildardo Gonzalez

2009-10-01

Rock cores of ~25 mm diameter are widely used in palaeomagnetism. Occasionally smaller diameters have been used as well which represents distinct advantages in terms of throughput, weight of equipment and core collections. How their orientation precision compares to 25 mm cores, however, has not been evaluated in detail before. Here we compare the site mean directions and their statistical parameters for 12 lava flows sampled with 25 mm cores (standard samples, typically 8 cores per site) and with 12 mm drill cores (mini-samples, typically 14 cores per site). The site-mean directions for both sample sizes appear to be indistinguishable in most cases. For the mini-samples, site dispersion parameters k on average are slightly lower than for the standard samples reflecting their larger orienting and measurement errors. Applying the Wilcoxon signed-rank test the probability that k or α95 have the same distribution for both sizes is acceptable only at the 17.4 or 66.3 per cent level, respectively. The larger mini-core numbers per site appears to outweigh the lower k values yielding also slightly smaller confidence limits α95. Further, both k and α95 are less variable for mini-samples than for standard size samples. This is interpreted also to result from the larger number of mini-samples per site, which better averages out the detrimental effect of undetected abnormal remanence directions. Sampling of volcanic rocks with mini-samples therefore does not present a disadvantage in terms of the overall obtainable uncertainty of site mean directions. Apart from this, mini-samples do present clear advantages during the field work, as about twice the number of drill cores can be recovered compared to 25 mm cores, and the sampled rock unit is then more widely covered, which reduces the contribution of natural random errors produced, for example, by fractures, cooling joints, and palaeofield inhomogeneities. Mini-samples may be processed faster in the laboratory, which is of

Development of the RANCOR Rotary-Percussive Coring System for Mars Sample Return

NASA Technical Reports Server (NTRS)

Paulsen, Gale; Indyk, Stephen; Zacny, Kris

2014-01-01

A RANCOR drill was designed to fit a Mars Exploration Rover (MER) class vehicle. The low mass of 3 kg was achieved by using the same actuator for three functions: rotation, percussions, and core break-off. Initial testing of the drill exposed an unexpected behavior of an off-the-shelf sprag clutch used to couple and decouple rotary-percussive function from the core break off function. Failure of the sprag was due to the vibration induced during percussive drilling. The sprag clutch would back drive in conditions where it was expected to hold position. Although this did not affect the performance of the drill, it nevertheless reduced the quality of the cores produced. Ultimately, the sprag clutch was replaced with a custom ratchet system that allowed for some angular displacement without advancing in either direction. Replacing the sprag with the ratchet improved the collected core quality. Also, premature failure of a 300-series stainless steel percussion spring was observed. The 300-series percussion spring was ultimately replaced with a music wire spring based on performances of previously designed rotary-percussive drill systems.

Individual and family environment correlates differ for consumption of core and non-core foods in children.

PubMed

Johnson, Laura; van Jaarsveld, Cornelia H M; Wardle, Jane

2011-03-01

Children's diets contain too few fruits and vegetables and too many foods high in saturated fat. Food intake is affected by multiple individual and family factors, which may differ for core foods (that are important to a healthy diet) and non-core foods (that are eaten more for pleasure than health). Data came from a sample of twins aged 11 years (n 342) and their parents from the Twins Early Development Study. Foods were categorised into two types: core (e.g. cereals, vegetables and dairy) and non-core (e.g. fats, crisps and biscuits). Parents' and children's intake was assessed by an FFQ. Mothers' and children's preference ratings and home availability were assessed for each food type. Parental feeding practices were assessed with the child feeding questionnaire and child television (TV) watching was maternally reported. Physical activity was measured using accelerometers. Correlates of the child's consumption of each food type were examined using a complex samples general linear model adjusted for potential confounders. Children's non-core food intake was associated with more TV watching, higher availability and greater maternal intake of non-core foods. Children's core food intake was associated with higher preferences for core foods and greater maternal intake of core foods. These results suggest that maternal intake influences both food types, while preferences affect intake of core foods but not of non-core foods, and availability and TV exposure were only important for non-core food intake. Cross-sectional studies cannot determine causality, but the present results suggest that different approaches may be needed to change the balance of core and non-core foods in children's diets.

Core-shifts and proper-motion constraints in the S5 polar cap sample at the 15 and 43 GHz bands

NASA Astrophysics Data System (ADS)

Abellán, F. J.; Martí-Vidal, I.; Marcaide, J. M.; Guirado, J. C.

2018-06-01

We have studied a complete radio sample of active galactic nuclei with the very-long-baseline-interferometry (VLBI) technique and for the first time successfully obtained high-precision phase-delay astrometry at Q band (43 GHz) from observations acquired in 2010. We have compared our astrometric results with those obtained with the same technique at U band (15 GHz) from data collected in 2000. The differences in source separations among all the source pairs observed in common at the two epochs are compatible at the 1σ level between U and Q bands. With the benefit of quasi-simultaneous U and Q band observations in 2010, we have studied chromatic effects (core-shift) at the radio source cores with three different methods. The magnitudes of the core-shifts are of the same order (about 0.1 mas) for all methods. However, some discrepancies arise in the orientation of the core-shifts determined through the different methods. In some cases these discrepancies are due to insufficient signal for the method used. In others, the discrepancies reflect assumptions of the methods and could be explained by curvatures in the jets and departures from conical jets.

A method for combined Sr-Nd-Hf isotopic analysis of <10 mg dust samples: implication for ice core science

NASA Astrophysics Data System (ADS)

Ujvari, Gabor; Wegner, Wencke; Klötzli, Urs

2017-04-01

Aeolian mineral dust particles below the size of 10-20 μm often experience longer distance transport in the atmosphere, and thus Aeolian dust is considered an important tracer of large-scale atmospheric circulation. Since ice core dust is purely Aeolian in origin, discrimination of its potential source region(s) can contribute to a better understanding of past dust activity and climatic/environmental causes. Furthermore, ice core dust source information provides critical experimental constraints for model simulations of past atmospheric circulation patterns [1,2]. However, to identify dust sources in past dust archives such as ice cores, the mineralogy and geochemistry of the wind-blown dust material must be characterized. While the amount of dust in marine cores or common terrestrial archives is sufficient for different types of analyses and even for multiple repeat measurements, dust content in ice cores is usually extremely low even for the peak dusty periods such as the Last Glacial Maximum (LGM) (5-8 mg dust/kg ice; [3]). Since the most powerful dust fingerprinting methods, such as REE composition and Sr-Nd-Pb isotopic analyses are destructive there is a clear need to establish sequential separation techniques of Sr, Nd, Pb and other REEs to get the most information out of small (5-10 mg) dust samples recovered from ice cores. Although Hf isotopes have recently been added as a robust tool of aerosol/dust source discrimination (e.g. [4,5,6,7]), precise Hf isotopic measurements of small (<10 mg) dust samples are still challenging due to the small Hf amounts (on the order of 1-10 ng) and often compromised by potential problems arising during ion exchange chemistry. In this pilot study an improved method for chemical separation of Sr, Nd and Hf by Bast et al. [8] was applied, which allows the precise isotope analysis of sub-ng amounts of Hf by MC-ICPMS. This ion exchange chromatography procedure has been combined with established methods of separating and

High Frequency Recordings of the Parkfield M=6 and its Aftershocks in the 1.1 km Deep SAFOD Pilot Hole

NASA Astrophysics Data System (ADS)

Malin, P.; Shalev, E.; Chavarria, A.

2004-12-01

Seismic waves from the September 28th Parkfield event and its aftershocks were recorded by the SAFOD Pilot Hole seismic array. This array currently consists of seven levels of 3-component 15 Hz seismometers within the Salinian granite. Its sensors are spaced at 40 m intervals between depths of 856 to 1156 meters below ground. Our deep borehole recordings with high signal-to-noise ratios has allowed us to explore the high frequency content and distribution of both the main event and a large number of aftershocks not detected by the local surface network. We have determined the spectral characteristics for events of different sizes and have related them to their source characteristics. Events close to the PH array contain surprisingly similar distributions of high frequency energy irrespective of their seismic moment. For example, the seismic waves of nearly co-located M~2 and M~5 aftershocks have instrument-corrected corner frequencies that are different by only a few Hz: ~58 Hz versus ~50 Hz. The M~5 can thus be thought of as having broken numerous small but strong fault patches - a model previously suggested by others based on both theoretical and observational grounds. The M~6, which was much further away than these aftershocks, also contains high frequency signals, not quite, but almost, to the same degree. Our results suggest that strong attenuation of high frequency waves in the fault zone area, as well as in shallow weathering layers, prevents more distantly located instruments from recording a complete picture of the actual radiation. Further, in keeping with this suggestion, we have found that, at least for the first nine minutes after the main event, the number of aftershocks observed at the PH is almost ten times higher than that reported in the NCEDC catalog. The rate and size of these events does not fit previous notions of aftershock activity, but may fit with our suggested heterogeneous fault patch and near-source attenuation models.

Analysis of Lunar Highland Regolith Samples From Apollo 16 Drive Core 64001/2 and Lunar Regolith Simulants - an Expanding Comparative Database

NASA Technical Reports Server (NTRS)

Schrader, Christian M.; Rickman, Doug; Stoeser, Douglas; Wentworth, Susan; McKay, Dave S.; Botha, Pieter; Butcher, Alan R.; Horsch, Hanna E.; Benedictus, Aukje; Gottlieb, Paul

2008-01-01

This slide presentation reviews the work to analyze the lunar highland regolith samples that came from the Apollo 16 core sample 64001/2 and simulants of lunar regolith, and build a comparative database. The work is part of a larger effort to compile an internally consistent database on lunar regolith (Apollo Samples) and lunar regolith simulants. This is in support of a future lunar outpost. The work is to characterize existing lunar regolith and simulants in terms of particle type, particle size distribution, particle shape distribution, bulk density, and other compositional characteristics, and to evaluate the regolith simulants by the same properties in comparison to the Apollo sample lunar regolith.

A sampler for coring sediments in rivers and estuaries

USGS Publications Warehouse

Prych, Edmund A.; Hubbell, D.W.

1966-01-01

A portable sampler developed to core submerged unconsolidated sediments collects cores that are 180 cm long and 4.75cm in diameter. The sampler is used from a 12-m boat in water depths up to 20 m and in flow velocities up to 1.5m per second to sample river and estuarine deposits ranging from silty clay to medium sand. Even in sand that cannot be penetrated with conventional corers, the sampler achieves easy penetration through the combined application of vibration, suction, and axial force. A piston in the core barrel creates suction, and the suspension system is arranged so that tension on the support cable produces both a downward force on the core barrel and a lateral support against overturning. Samples are usually retained because of slight compaction in the driving head; as a precaution, however, the bottom of the core barrel is covered by a plate that closes after the barrel is withdrawn from the bed. Tests show that sample-retainers placed within the driving head restrict penetration and limit core lengths. Stratification within cores is disrupted little as a result of the sampling process.

Preliminary biological sampling of GT3 and BT1 cores and the microbial community dynamics of existing subsurface wells

NASA Astrophysics Data System (ADS)

Kraus, E. A.; Stamps, B. W.; Rempfert, K. R.; Ellison, E. T.; Nothaft, D. B.; Boyd, E. S.; Templeton, A. S.; Spear, J. R.

2017-12-01

Subsurface microbial life is poorly understood but potentially very important to the search for life on other planets as well as increasing our understanding of Earth's geobiological processes. Fluids and rocks of actively serpentinizing subsurface environments are a recent target of biological study due to their apparent ubiquity across the solar system. Areas of serpentinization can contain high concentrations of molecular hydrogen, H2, that can serve as the dominant fuel source for subsurface microbiota. Working with the Oman Drilling Project, DNA and RNA were extracted from fluids of seven alkaline wells and two rock cores from drill sites GT3 and BT1 within the Samail ophiolite. DNA and cDNA (produced via reverse transcription from the recovered RNA) were sequenced using universal primers to identify microbial life across all three domains. Alkaline subsurface fluids support a microbial community that changes with pH and host-rock type. In peridotite with pH values of >11, wells NSHQ 14 and WAB 71 have high relative abundances of Meiothermus, Methanobacterium, the family Nitrospiraceae, and multiple types of the class Dehalococcoidia. While also hosted in peridotite but at pH 8.5, wells WAB 104 and 105 have a distinct, more diverse microbial community. This increased variance in community make-up is seen in wells that sit near/at the contact of gabbro and peridotite formations as well. Core results indicate both sampled rock types host a very low biomass environment subject to multiple sources of contamination during the drilling process. Suggestions for contaminant reduction, such as having core handlers wear nitrile gloves and flame-sterilizing the outer surfaces of core rounds for biological sampling, would have minimal impact to overall ODP coreflow and maximize the ability to better understand in situ microbiota in this low-biomass serpentinizing subsurface environment. While DNA extraction was successful with gram amounts of crushed rock, much can be

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.

Observing the San Andreas Fault at Depth

NASA Astrophysics Data System (ADS)

Ellsworth, W.; Hickman, S.; Zoback, M.; Davis, E.; Gee, L.; Huggins, R.; Krug, R.; Lippus, C.; Malin, P.; Neuhauser, D.; Paulsson, B.; Shalev, E.; Vajapeyam, B.; Weiland, C.; Zumberge, M.

2005-12-01

Extending 4 km into the Earth along a diagonal path that crosses the divide between Salinian basement accreted to the Pacific Plate and Cretaceous sediments of North America, the main hole at the San Andreas Fault Observatory at Depth (SAFOD) was designed to provide a portal into the inner workings of a major plate boundary fault. The successful drilling and casing of the main hole in the summer of 2005 to a total vertical depth of 3.1 km make it possible to conduct spatially extensive and long-duration observations of active tectonic processes within the actively deforming core of the San Andreas Fault. In brief, the observatory consists of retrievable seismic, deformation and environmental sensors deployed inside the casing in both the main hole (maximum temperature 135 C) and the collocated pilot hole (1.1 km depth), and a fiber optic strainmeter installed behind casing in the main hole. By using retrievable systems deployed on either wire line or rigid tubing, each hole can be used for a wide range of scientific purposes, with instrumentation that takes maximum advantage of advances in sensor technology. To meet the scientific and technical challenges of building the observatory, borehole instrumentation systems developed for use in the petroleum industry and by the academic community in other deep research boreholes have been deployed in the SAFOD pilot hole and main hole over the past year. These systems included 15Hz omni-directional and 4.5 Hz gimbaled seismometers, micro-electro-mechanical accelerometers, tiltmeters, sigma-delta digitizers, and a fiber optic interferometeric strainmeter. A 1200-m-long, 3-component 80-level clamped seismic array was also operated in the main hole for 2 weeks of recording in May of 2005, collecting continuous seismic data at 4000 sps. Some of the observational highlights include capturing one of the M 2 SAFOD target repeating earthquakes in the near-field at a distance of 420 m, with accelerations of up to 200 cm/s and a

Laboratory measurements of the seismic velocities and other petrophysical properties of the Outokumpu deep drill core samples, eastern Finland

NASA Astrophysics Data System (ADS)

Elbra, Tiiu; Karlqvist, Ronnie; Lassila, Ilkka; Høgström, Edward; Pesonen, Lauri J.

2011-01-01

Petrophysical, in particular seismic velocity, measurements of the Outokumpu deep drill core (depth 2.5 km) have been carried out to characterize the geophysical nature of the Paleoproterozoic crustal section of eastern Finland and to find lithological and geophysical interpretations to the distinct crustal reflectors as observed in seismic surveys. The results show that different lithological units can be identified based on the petrophysical data. The density of the samples remained nearly constant throughout the drilled section. Only diopside-tremolite skarns and black schists exhibit higher densities. The samples are dominated by the paramagnetic behaviour with occasional ferromagnetic signature caused by serpentinitic rocks. Large variations in seismic velocities, both at ambient pressure and under in situ crustal conditions are observed. The porosity of the samples, which is extremely low, is either intrinsic by nature or caused by decompaction related to fracturing during the core retrieval. It is noteworthy that these microfractures have dramatically lowered the VP and VS values. From the measured velocities and density data we have calculated the seismic impedances, Young's modulus and Poisson's ratios for the lithological units of the Outokumpu section and from these data the reflection coefficients for the major lithological boundaries, evident in the surveyed section, were determined. The data show that the strong and distinct reflections visible in wide-angle seismic surveys are caused by interfaces between diopside-tremolite skarn and either serpentinites, mica schist or black schist.

Biliary plastic stent does not influence the accuracy of endoscopic ultrasound-guided sampling of pancreatic head masses performed with core biopsy needles.

PubMed

Antonini, Filippo; Fuccio, Lorenzo; Giorgini, Sara; Fabbri, Carlo; Frazzoni, Leonardo; Scarpelli, Marina; Macarri, Giampiero

2017-08-01

While the presence of biliary stent significantly decreases the accuracy of endoscopic ultrasound (EUS) for pancreatic head cancer staging, its impact on the EUS-guided sampling accuracy is still debated. Furthermore, data on EUS-fine needle biopsy (EUS-FNB) using core biopsy needles in patients with pancreatic mass and biliary stent are lacking. The aim of this study was to evaluate the influence of biliary stent on the adequacy and accuracy of EUS-FNB in patients with pancreatic head mass. All patients who underwent EUS-guided sampling with core needles of solid pancreatic head masses causing obstructive jaundice were retrospectively identified in a single tertiary referral center. Adequacy, defined as the rate of cases in which a tissue specimen for proper examination was achieved, with and without biliary stent, was the primary outcome measure. The diagnostic accuracy and complication rate were the secondary outcome measures. A total of 130 patients with pancreatic head mass causing biliary obstruction were included in the study: 74 cases of them were sampled without stent and 56 cases with plastic stent in situ. The adequacy was 96.4% in the stent group and 90.5% in the group without stent (p=0.190). No significant differences were observed for sensitivity (88.9% vs. 85.9%), specificity (100% for both groups), and accuracy (89.3% vs. 86.5%) between those with and without stent, respectively. The accuracy was not influenced by the timing of stenting (<48h or ≥48h before EUS). No EUS-FNB related complications were recorded. The presence of biliary stent does not influence the tissue sampling adequacy, the diagnostic accuracy and the complication rate of EUS-FNB of pancreatic head masses performed with core biopsy needles. Copyright © 2017 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Praying Mantis Bending Core Breakoff and Retention Mechanism

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Lindermann, Randel A.

2011-01-01

Sampling cores requires the controlled breakoff of the core at a known location with respect to the drill end. An additional problem is designing a mechanism that can be implemented at a small scale, yet is robust and versatile enough to be used for a variety of core samples. The new design consists of a set of tubes (a drill tube, an outer tube, and an inner tube) and means of sliding the inner and outer tubes axially relative to each other. Additionally, a sample tube can be housed inside the inner tube for storing the sample. The inner tube fits inside the outer tube, which fits inside the drill tube. The inner and outer tubes can move axially relative to each other. The inner tube presents two lamellae with two opposing grabbing teeth and one pushing tooth. The pushing tooth is offset axially from the grabbing teeth. The teeth can move radially and their motion is controlled by the outer tube. The outer tube presents two lamellae with radial extrusions to control the inner tube lamellae motion. In breaking the core, the mechanism creates two support points (the grabbing teeth and the bit tip) and one push point. The core is broken in bending. The grabbing teeth can also act as a core retention mechanism. The praying mantis that is disclosed herein is an active core breaking/retention mechanism that requires only one additional actuator other than the drilling actuator. It can break cores that are attached to the borehole bottom as

Nanoparticle functionalised small-core suspended-core fibre - a novel platform for efficient sensing.

PubMed

Doherty, Brenda; Csáki, Andrea; Thiele, Matthias; Zeisberger, Matthias; Schwuchow, Anka; Kobelke, Jens; Fritzsche, Wolfgang; Schmidt, Markus A

2017-02-01

Detecting small quantities of specific target molecules is of major importance within bioanalytics for efficient disease diagnostics. One promising sensing approach relies on combining plasmonically-active waveguides with microfluidics yielding an easy-to-use sensing platform. Here we introduce suspended-core fibres containing immobilised plasmonic nanoparticles surrounding the guiding core as a concept for an entirely integrated optofluidic platform for efficient refractive index sensing. Due to the extremely small optical core and the large adjacent microfluidic channels, over two orders of magnitude of nanoparticle coverage densities have been accessed with millimetre-long sample lengths showing refractive index sensitivities of 170 nm/RIU for aqueous analytes where the fibre interior is functionalised by gold nanospheres. Our concept represents a fully integrated optofluidic sensing system demanding small sample volumes and allowing for real-time analyte monitoring, both of which are highly relevant within invasive bioanalytics, particularly within molecular disease diagnostics and environmental science.

Evaluating Long-Term Impacts of Soil-Mixing Source-Zone Treatment using Cryogenic Core Collection

DTIC Science & Technology

2017-06-01

to (a) coring equipment freezing downhole, (b) freezing or binding of the core sample in barrel, and ( c ) running out of LN in the vicinity of sampling...encountered due to (a) coring equipment freezing downhole, (b) freezing or binding of the core sample in barrel, and ( c ) running out of LN in the...equipment freezing downhole, (b) freezing or binding of the core sample in barrel, and ( c ) running out of LN in the vicinity of sampling. Downhole

Concentration of Antifouling Biocides and Metals in Sediment Core Samples in the Northern Part of Hiroshima Bay

PubMed Central

Tsunemasa, Noritaka; Yamazaki, Hideo

2014-01-01

Accumulation of Ot alternative antifoulants in sediment is the focus of this research. Much research had been done on surface sediment, but in this report, the accumulation in the sediment core was studied. The Ot alternative antifoulants, Diuron, Sea-Nine211, and Irgarol 1051, and the latter’s degradation product, M1, were investigated in five samples from the northern part of Hiroshima Bay. Ot compounds (tributyltin (TBT) and triphenyltin (TPT)) were also investigated for comparison. In addition, metal (Pb, Cu, Zn, Fe and Mn) levels and chronology were measured to better understand what happens after accumulation on the sea floor. It was discovered that Ot alternative antifoulant accumulation characteristics in sediment were like Ot compounds, with the concentration in the sediment core being much higher than surface sediment. The concentration in sediment seems to have been affected by the regulation of Ot compounds in 1990, due to the concentration of Ot alternative antifoulants and Ot compounds at the survey point in front of the dock, showing an increase from almost the same layer after the regulation. PMID:24901529

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.

Constraints on the Location of γ-Ray Sample of Blazars with Radio Core-shift Measurements

NASA Astrophysics Data System (ADS)

Wu, Linhui; Wu, Qingwen; Yan, Dahai; Chen, Liang; Fan, Xuliang

2018-01-01

We model simultaneous or quasi-simultaneous multi-band spectral energy distributions (SEDs) for a sample of 25 blazars that have radio core-shift measurements, where a one-zone leptonic model and Markov chain Monte Carlo technique are adopted. In the SED fitting for 23 low-synchrotron-peaked (LSP) blazars, the seed photons from the broad-line (BLR) and molecular torus are considered respectively in the external Compton process. We find that the SED fitting with the seed photons from the torus are better than those utilizing BLR photons, which suggest that the γ-ray emitting region may be located outside the BLR. Assuming the magnetic field strength in the γ-ray emitting region as constrained from the SED fitting follows the magnetic field distribution as derived from the radio core-shift measurements (i.e., B{(R)≃ {B}1{pc}(R/1{pc})}-1, where R is the distance from the central engine and {B}1{pc} is the magnetic field strength at 1 pc), we further calculate the location of the γ-ray emitting region, {R}γ , for these blazars. We find that {R}γ ∼ 2× {10}4{R}{{S}}≃ 10 {R}{BLR} ({R}{{S}} is the Schwarzschild radius and {R}{BLR} is the BLR size), where {R}{BLR} is estimated from the broad-line luminosities using the empirical correlations obtained using the reverberation mapping methods.

Probing the Inner Core with P'P'

NASA Astrophysics Data System (ADS)

Day, E. A.; Irving, J. C. E.

2015-12-01

Geophysical observations of the inner core today improve our understanding not just of the processes occurring in the core at the present, but also those that have occurred in the past. As the inner core freezes it may record clues as to the state of the Earth at the time of growth, although the texture of the inner core may also be modified through post-solidification mechanisms. The seismic structure of the inner core is not simple; the dominant pattern is one of anisotropic and isotropic differences between the Eastern and Western 'hemispheres' of the inner core. Additionally, there is evidence for an innermost inner core, layering of the uppermost inner core, and possibly super-rotation of the inner core relative to the mantle. Most body wave studies of inner core structure use PKP-PKIKP differential travel times to constrain velocity variations within the inner core. However, body wave studies are inherently limited by the geometry of fixed sources and stations, and thus there are some areas of the inner core that are relatively under-sampled, even in today's data-rich world. Here, we examine the differential travel times of the different branches of P'P' (PKIKPPKIKP and PKPPKP), comparing the arrival time of inner core sensitive branch, P'P'df, with the arrival times of branches that only reach the outer core. By using P'P' we are able to exploit alternative ray geometries and sample different regions of the inner core to those areas accessible to studies which utilize PKIKP. We use both linear and non-linear stacking methods to make observations of small amplitude P'P' phases. These measurements match the broad scale hemispherical pattern of anisotropy in the inner core.

Ice core carbonyl sulfide measurements from a new South Pole ice core (SPICECORE)

NASA Astrophysics Data System (ADS)

Aydin, M.; Nicewonger, M. R.; Saltzman, E. S.

2017-12-01

Carbonyl sulfide (COS) is the most abundant sulfur gas in the troposphere with a present-day mixing ratio of about 500 ppt. Direct and indirect emissions from the oceans are the predominant sources of atmospheric COS. The primary removal mechanism is uptake by terrestrial plants during photosynthesis. Because plants do not respire COS, atmospheric COS levels are linked to terrestrial gross primary productivity (GPP). Ancient air trapped in polar ice cores has been used to reconstruct COS records of the past atmosphere, which can be used to infer past GPP variability and potential changes in oceanic COS emission. We are currently analyzing samples from a newly drilled intermediate depth ice core from South Pole, Antarctica (SPICECORE). This core is advantageous for studying COS because the cold temperatures of South Pole ice lead to very slow rates of in situ loss due to hydrolysis. One hundred and eighty-four bubbly ice core samples have been analyzed to date with gas ages ranging from about 9.2 thousand (733 m depth) to 75 years (126 m depth) before present. After a 2% correction for gravitational enrichment in the firn, the mean COS mixing ratio for the data set is 312±15 ppt (±1s), with the data set median also equal to 312 ppt. The only significant long-term trend in the record is a 5-10% increase in COS during the last 2-3 thousand years of the Holocene. The SPICECORE data agree with previously published ice core COS records from other Antarctic sites during times of overlap, confirming earlier estimates of COS loss rates to in situ hydrolysis in ice cores. Antarctic ice core data place strict constraints on the COS mixing ratio and its range of variability in the southern hemisphere atmosphere during the last several millennia. Implications for the atmospheric COS budget will be discussed.

Enhanced conformational sampling using enveloping distribution sampling.

PubMed

Lin, Zhixiong; van Gunsteren, Wilfred F

2013-10-14

To lessen the problem of insufficient conformational sampling in biomolecular simulations is still a major challenge in computational biochemistry. In this article, an application of the method of enveloping distribution sampling (EDS) is proposed that addresses this challenge and its sampling efficiency is demonstrated in simulations of a hexa-β-peptide whose conformational equilibrium encompasses two different helical folds, i.e., a right-handed 2.7(10∕12)-helix and a left-handed 3(14)-helix, separated by a high energy barrier. Standard MD simulations of this peptide using the GROMOS 53A6 force field did not reach convergence of the free enthalpy difference between the two helices even after 500 ns of simulation time. The use of soft-core non-bonded interactions in the centre of the peptide did enhance the number of transitions between the helices, but at the same time led to neglect of relevant helical configurations. In the simulations of a two-state EDS reference Hamiltonian that envelops both the physical peptide and the soft-core peptide, sampling of the conformational space of the physical peptide ensures that physically relevant conformations can be visited, and sampling of the conformational space of the soft-core peptide helps to enhance the transitions between the two helices. The EDS simulations sampled many more transitions between the two helices and showed much faster convergence of the relative free enthalpy of the two helices compared with the standard MD simulations with only a slightly larger computational effort to determine optimized EDS parameters. Combined with various methods to smoothen the potential energy surface, the proposed EDS application will be a powerful technique to enhance the sampling efficiency in biomolecular simulations.

Inner Core Tomography Under Africa

NASA Astrophysics Data System (ADS)

Irving, J. C. E.

2014-12-01

Hemispherical structure in the inner core has been observed using both normal mode and body wave data, but the more regional scale properties of the inner core are still the subject of ongoing debate. The nature of the vertical boundary regions between the eastern and western hemispheres will be an important constraint on dynamical processes at work in the inner core. With limited data available, earlier inner core studies defined each boundary using one line of longitude, but this may not be a sufficient description for what could be one of the inner core's most heterogeneous regions. Here, I present a large, hand-picked dataset of PKPbc-PKPdf differential travel times which sample the inner core under Africa, where the proposed position of one hemisphere boundary is located. The dataset contains polar, intermediate and equatorial rays through the inner core, and the presence of crossing raypaths makes regional-scale tomography of the inner core feasible. I invert the data to find regional variations in inner core anisotropy under different parts of Africa, and present both anisotropy and voigt isotropic velocity variations of this important portion of the inner core.

An Ice Core Melter System for Continuous Major and Trace Chemical Analyses of a New Mt. Logan Summit Ice Core

NASA Astrophysics Data System (ADS)

Osterberg, E. C.; Handley, M. J.; Sneed, S. D.; Mayewski, P. A.; Kreutz, K. J.; Fisher, D. A.

2004-12-01

The ice core melter system at the University of Maine Climate Change Institute has been recently modified and updated to allow high-resolution (<1-2 cm ice/sample), continuous and coregistered sampling of ice cores, most notably the 2001 Mt. Logan summit ice core (187 m to bedrock), for analyses of 34 trace elements (Sr, Cd, Sb, Cs, Ba, Pb, Bi, U, As, Al, S, Ca, Ti, V, Cr, Mn, Fe, Co, Cu, Zn, REE suite) by inductively coupled plasma mass spectrometry (ICP-MS), 8 major ions (Na+, Ca2+, Mg2+, K+, Cl-, SO42-, NO3-, MSA) by ion chromatography (IC), stable water isotopes (δ 18O, δ D, d) and volcanic tephra. The UMaine continuous melter (UMCoM) system is housed in a dedicated clean room with HEPA filtered air. Standard clean room procedures are employed during melting. A Wagenbach-style continuous melter system has been modified to include a pure Nickel melthead that can be easily dismantled for thorough cleaning. The system allows melting of both ice and firn without wicking of the meltwater into unmelted core. Contrary to ice core melter systems in which the meltwater is directly channeled to online instruments for continuous flow analyses, the UMCoM system collects discrete samples for each chemical analysis under ultraclean conditions. Meltwater from the pristine innermost section of the ice core is split between one fraction collector that accumulates ICP-MS samples in acid pre-cleaned polypropylene vials under a class-100 HEPA clean bench, and a second fraction collector that accumulates IC samples. A third fraction collector accumulates isotope and tephra samples from the potentially contaminated outer portion of the core. This method is advantageous because an archive of each sample remains for subsequent analyses (including trace element isotope ratios), and ICP-MS analytes are scanned for longer intervals and in replicate. Method detection limits, calculated from de-ionized water blanks passed through the entire UMCoM system, are below 10% of average Mt

Hydrothermal frictional strengths of rock and mineral samples relevant to the creeping section of the San Andreas Fault

USGS Publications Warehouse

Moore, Diane E.; Lockner, David A.; Hickman, Stephen H.

2016-01-01

We compare frictional strengths in the temperature range 25–250 °C of fault gouge from SAFOD (CDZ and SDZ) with quartzofeldspathic wall rocks typical of the central creeping section of the San Andreas Fault (Great Valley sequence and Franciscan Complex). The Great Valley and Franciscan samples have coefficients of friction, μ > 0.35 at all experimental conditions. Strength is unchanged between 25° and 150 °C, but μ increases at higher temperatures, exceeding 0.50 at 250 °C. Both samples are velocity strengthening at room temperature but show velocity-weakening behavior beginning at 150 °C and stick-slip motion at 250 °C. These rocks, therefore, have the potential for unstable seismic slip at depth. The CDZ gouge, with a high saponite content, is weak (μ = 0.09–0.17) and velocity strengthening in all experiments, and μ decreases at temperatures above 150 °C. Behavior of the SDZ is intermediate between the CDZ and wall rocks: μ < 0.2 and does not vary with temperature. Although saponite is probably not stable at depths greater than ∼3 km, substitution of the frictionally similar minerals talc and Mg-rich chlorite for saponite at higher temperatures could potentially extend the range of low strength and stable slip down to the base of the seismogenic zone.

Composition of Apollo 17 core 76001

NASA Technical Reports Server (NTRS)

Korotev, Randy L.; Bishop, Kaylynn M.

1993-01-01

Core 76001 is a single drive tube containing a column of regolith taken at the base of the North Massif, station 6, Apollo 17. The core material is believed to have accumulated through slow downslope mass wasting from the massif. As a consequence, the core soil is mature throughout its length. Results of INAA for samples taken every half centimeter along the length of the core indicate that there is only minor systematic compositional variation with depth. Concentrations of elements primarily associated with mare basalt (Sc, Fe) and noritic impact melt breccia (Sm) decrease slightly with depth, particularly between 20 cm and the bottom of the core at 32 cm depth. This is consistent with petrographic studies that indicate a greater proportion of basalt and melt breccia in the top part of the core. However, Sm/Sc and La/Sm ratios are remarkably constant with depth, indicating no variation in the ratio of mare material to Sm-rich highlands material with depth. Other than these subtle changes, there is no compositional evidence for the two stratigraphic units (0-20 cm and 20-32 cm) defined on the basis of modal petrography, although all samples with anomalously high Ni concentrations (Fe-Ni metal nuggets) occur above 20 cm depth.

Physical-Property Measurements on Core samples from Drill-Holes DB-1 and DB-2, Blue Mountain Geothermal Prospect, North-Central Nevada

USGS Publications Warehouse

Ponce, David A.; Watt, Janet T.; Casteel, John; Logsdon, Grant

2009-01-01

From May to June 2008, the U.S. Geological Survey (USGS) collected and measured physical properties on 36 core samples from drill-hole Deep Blue No. 1 (DB-1) and 46 samples from drill-hole Deep Blue No. 2 (DB-2) along the west side of Blue Mountain about 40 km west of Winnemucca, Nev. These data were collected as part of an effort to determine the geophysical setting of the Blue Mountain geothermal prospect as an aid to understanding the geologic framework of geothermal systems throughout the Great Basin. The physical properties of these rocks and other rock types in the area create a distinguishable pattern of gravity and magnetic anomalies that can be used to infer their subsurface geologic structure. Drill-holes DB-1 and DB-2 were spudded in alluvium on the western flank of Blue Mountain in 2002 and 2004, respectively, and are about 1 km apart. Drill-hole DB-1 is at a ground elevation of 1,325 m and was drilled to a depth of 672 m and drill-hole DB-2 is at a ground elevation of 1,392 m and was drilled to a depth of 1522 m. Diameter of the core samples is 6.4 cm. These drill holes penetrate Jurassic and Triassic metasedimentary rocks predominantly consisting of argillite, mudstone, and sandstone; Tertiary diorite and gabbro; and younger Tertiary felsic dikes.

Characterization of the San Andreas Fault at Parkfield Using a Massive 3D VSP

NASA Astrophysics Data System (ADS)

Chavarria, J.; Goertz, A.; Karrenbach, M.; Milligan, P.; Paulsson, B.

2005-12-01

In preparation for the drilling of SAFOD's Phase II we installed an 80 level array of 3C seismometers inside the well. The goal of the array was to refine the existing velocity model to better locate the target events, and to monitor the local seismicity. The array, with sensors laying mostly within the deviated portion of the well, spans depths ranging from 2.7 to 1.5 km with levels every 15 m. It is this dense spacing what makes 3D VSP capable of bridging the gap between drill-hole observations and observations from the surface like 2D seismics. During April and May 2005 we recorded thirteen far offset shots surrounding the SAFOD site and target event area. Data from these shots was simultaneously recorded by the surface networks and used for better location of the target events. In addition to these, a zero offset shot at SAFOD was generated to refine the structure surrounding the well. The 1D velocity model inverted from the zero offset is representative of the current geologic model at SAFOD. The complexity of the velocity model for this segment of the fault can be inferred from deviations between the zero offset model and the shorter wavelength model derived from well logs. In addition to strong changes in velocity, both zero offset and far offset shots show the presence of strong scattered phases associated to the complex geologic structure of the San Andreas Fault Zone. In addition to the active portion of the experiment we monitored the local seismicity (i.e. aftershocks from the Parkfield 2004 event) over a period of 13 days. During this period of time we recorded continuously at high sampling rates (4kHz) a large number of events, some of which were located by the surface networks and felt onsite. The quiet environment in the borehole enabled us to record microearthquakes that were not present in the NCEDC catalog. In some cases these small events were not even recorded along the entire array. Besides its high level of event detection, the high vector

HPLC column-switching technique for sample preparation and fluorescence determination of propranolol in urine using fused-core columns in both dimensions.

PubMed

Satínský, Dalibor; Havlíková, Lucie; Solich, Petr

2013-08-01

A new and fast high-performance liquid chromatography (HPLC) column-switching method using fused-core columns in both dimensions for sample preconcentration and determination of propranolol in human urine has been developed. On-line sample pretreatment and propranolol preconcentration were performed on an Ascentis Express RP-C-18 guard column (5 × 4.6 mm), particle size, 2.7 μm, with mobile phase acetonitrile/water (5:95, v/v) at a flow rate of 2.0 mL min(-1) and at a temperature of 50 °C. Valve switch from pretreatment column to analytical column was set at 4.0 min in a back-flush mode. Separation of propranolol from other endogenous urine compounds was achieved on the fused-core column Ascentis Express RP-Amide (100 × 4.6 mm), particle size, 2.7 μm, with mobile phase acetonitrile/water solution of 0.5% triethylamine, pH adjusted to 4.5 by means of glacial acetic acid (25:75, v/v), at a flow rate of 1.0 mL min(-1) and at a temperature of 50 °C. Fluorescence excitation/emission detection wavelengths were set at 229/338 nm. A volume of 1,500 μL of filtered urine sample solution was injected directly into the column-switching HPLC system. The total analysis time including on-line sample pretreatment was less than 8 min. The experimentally determined limit of detection of the method was found to be 0.015 ng mL(-1).

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.

Biospecimen Core Resource - TCGA

Cancer.gov

The Cancer Genome Atlas (TCGA) Biospecimen Core Resource centralized laboratory reviews and processes blood and tissue samples and their associated data using optimized standard operating procedures for the entire TCGA Research Network.

Effects of Re-heating Tissue Samples to Core Body Temperature on High-Velocity Ballistic Projectile-tissue Interactions.

PubMed

Humphrey, Caitlin; Henneberg, Maciej; Wachsberger, Christian; Maiden, Nicholas; Kumaratilake, Jaliya

2017-11-01

Damage produced by high-speed projectiles on organic tissue will depend on the physical properties of the tissues. Conditioning organic tissue samples to human core body temperature (37°C) prior to conducting ballistic experiments enables their behavior to closely mimic that of living tissues. To minimize autolytic changes after death, the tissues are refrigerated soon after their removal from the body and re-heated to 37°C prior to testing. This research investigates whether heating 50-mm-cube samples of porcine liver, kidney, and heart to 37°C for varying durations (maximum 7 h) can affect the penetration response of a high-speed, steel sphere projectile. Longer conditioning times for heart and liver resulted in a slight loss of velocity/energy of the projectile, but the reverse effect occurred for the kidney. Possible reasons for these trends include autolytic changes causing softening (heart and liver) and dehydration causing an increase in density (kidney). © 2017 American Academy of Forensic Sciences.

Investigating the soil removal characteristics of flexible tube coring method for lunar exploration

NASA Astrophysics Data System (ADS)

Tang, Junyue; Quan, Qiquan; Jiang, Shengyuan; Liang, Jieneng; Lu, Xiangyong; Yuan, Fengpei

2018-02-01

Compared with other technical solutions, sampling the planetary soil and returning it back to Earth may be the most direct method to seek the evidence of extraterrestrial life. To keep sample's stratification for further analyzing, a novel sampling method called flexible tube coring has been adopted for China future lunar explorations. Given the uncertain physical properties of lunar regolith, proper drilling parameters should be adjusted immediately in piercing process. Otherwise, only a small amount of core could be sampled and overload drilling faults could occur correspondingly. Due to the fact that the removed soil is inevitably connected with the cored soil, soil removal characteristics may have a great influence on both drilling loads and coring results. To comprehend the soil removal characteristics, a non-contact measurement was proposed and verified to acquire the coring and removal results accurately. Herein, further more experiments in one homogenous lunar regolith simulant were conducted, revealing that there exists a sudden core failure during the sampling process and the final coring results are determined by the penetration per revolution index. Due to the core failure, both drilling loads and soil's removal states are also affected thereby.

Family and infant characteristics associated with timing of core and non-core food introduction in early childhood.

PubMed

Schrempft, S; van Jaarsveld, C H M; Fisher, A; Wardle, J

2013-06-01

To identify family and infant characteristics associated with timing of introduction of two food types: core foods (nutrient-dense) and non-core foods (nutrient-poor) in a population-based sample of mothers and infants. Participants were 1861 mothers and infants from the Gemini twin birth cohort (one child per family). Family and infant characteristics were assessed when the infants were around 8 months old. Timing of introducing core and non-core foods was assessed at 8 and 15 months. As the distributions of timing were skewed, three similar-sized groups were created for each food type: earlier (core: 1-4 months; non-core: 3-8 months), average (core: 5 months; non-core: 9-10 months) and later introduction (core: 6-12 months; non-core: 11-18 months). Ordinal logistic regression was used to examine predictors of core and non-core food introduction, with bootstrapping to test for differences between the core and non-core models. Younger maternal age, lower education level and higher maternal body mass index were associated with earlier core and non-core food introduction. Not breastfeeding for at least 3 months and higher birth weight were specifically associated with earlier introduction of core foods. Having older children was specifically associated with earlier introduction of non-core foods. There are similarities and differences in the characteristics associated with earlier introduction of core and non-core foods. Successful interventions may require a combination of approaches to target both food types.

Measurements of ethane in Antarctic ice cores

NASA Astrophysics Data System (ADS)

Verhulst, K. R.; Fosse, E. K.; Aydin, K. M.; Saltzman, E. S.

2011-12-01

Ethane is one of the most abundant hydrocarbons in the atmosphere. The major ethane sources are fossil fuel production and use, biofuel combustion, and biomass-burning emissions and the primary loss pathway is via reaction with OH. A paleoatmospheric ethane record would be useful as a tracer of biomass-burning emissions, providing a constraint on past changes in atmospheric methane and methane isotopes. An independent biomass-burning tracer would improve our understanding of the relationship between biomass burning and climate. The mean annual atmospheric ethane level at high southern latitudes is about 230 parts per trillion (ppt), and Antarctic firn air measurements suggest that atmospheric ethane levels in the early 20th century were considerably lower (Aydin et al., 2011). In this study, we present preliminary measurements of ethane (C2H6) in Antarctic ice core samples with gas ages ranging from 0-1900 C.E. Samples were obtained from dry-drilled ice cores from South Pole and Vostok in East Antarctica, and from the West Antarctic Ice Sheet Divide (WAIS-D). Gases were extracted from the ice by melting under vacuum in a glass vessel sealed by indium wire and were analyzed using high resolution GC/MS with isotope dilution. Ethane levels measured in ice core samples were in the range 100-220 ppt, with a mean of 157 ± 45 ppt (n=12). System blanks contribute roughly half the amount of ethane extracted from a 300 g ice core sample. These preliminary data exhibit a temporal trend, with higher ethane levels from 0-900 C.E., followed by a decline, reaching a minimum between 1600-1700 C.E. These trends are consistent with variations in ice core methane isotopes and carbon monoxide isotopes (Ferretti et al., 2005, Wang et al., 2010), which indicate changes in biomass burning emissions over this time period. These preliminary data suggest that Antarctic ice core bubbles contain paleoatmospheric ethane levels. With further improvement of laboratory techniques it appears

A new set-up for simultaneous high-precision measurements of CO2, δ13C-CO2 and δ18O-CO2 on small ice core samples

NASA Astrophysics Data System (ADS)

Jenk, Theo Manuel; Rubino, Mauro; Etheridge, David; Ciobanu, Viorela Gabriela; Blunier, Thomas

2016-08-01

Palaeoatmospheric records of carbon dioxide and its stable carbon isotope composition (δ13C) obtained from polar ice cores provide important constraints on the natural variability of the carbon cycle. However, the measurements are both analytically challenging and time-consuming; thus only data exist from a limited number of sampling sites and time periods. Additional analytical resources with high analytical precision and throughput are thus desirable to extend the existing datasets. Moreover, consistent measurements derived by independent laboratories and a variety of analytical systems help to further increase confidence in the global CO2 palaeo-reconstructions. Here, we describe our new set-up for simultaneous measurements of atmospheric CO2 mixing ratios and atmospheric δ13C and δ18O-CO2 in air extracted from ice core samples. The centrepiece of the system is a newly designed needle cracker for the mechanical release of air entrapped in ice core samples of 8-13 g operated at -45 °C. The small sample size allows for high resolution and replicate sampling schemes. In our method, CO2 is cryogenically and chromatographically separated from the bulk air and its isotopic composition subsequently determined by continuous flow isotope ratio mass spectrometry (IRMS). In combination with thermal conductivity measurement of the bulk air, the CO2 mixing ratio is calculated. The analytical precision determined from standard air sample measurements over ice is ±1.9 ppm for CO2 and ±0.09 ‰ for δ13C. In a laboratory intercomparison study with CSIRO (Aspendale, Australia), good agreement between CO2 and δ13C results is found for Law Dome ice core samples. Replicate analysis of these samples resulted in a pooled standard deviation of 2.0 ppm for CO2 and 0.11 ‰ for δ13C. These numbers are good, though they are rather conservative estimates of the overall analytical precision achieved for single ice sample measurements. Facilitated by the small sample requirement

Collecting, preparing, crossdating, and measuring tree increment cores

USGS Publications Warehouse

Phipps, R.L.

1985-01-01

Techniques for collecting and handling increment tree cores are described. Procedures include those for cleaning and caring for increment borers, extracting the sample from a tree, core surfacing, crossdating, and measuring. (USGS)

Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod

PubMed Central

Schwing, Patrick T.; Romero, Isabel C.; Larson, Rebekka A.; O'Malley, Bryan J.; Fridrik, Erika E.; Goddard, Ethan A.; Brooks, Gregg R.; Hastings, David W.; Rosenheim, Brad E.; Hollander, David J.; Grant, Guy; Mulhollan, Jim

2016-01-01

Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, this resolution provides records at the annual to decadal scale, at best. An extrusion method, using a calibrated, threaded-rod is presented here, which allows for millimeter-scale subsampling of aquatic sediment cores of varying diameters. Millimeter scale subsampling allows for sub-annual to monthly analysis of the sedimentary record, an order of magnitude higher than typical sampling schemes. The extruder consists of a 2 m aluminum frame and base, two core tube clamps, a threaded-rod, and a 1 m piston. The sediment core is placed above the piston and clamped to the frame. An acrylic sampling collar is affixed to the upper 5 cm of the core tube and provides a platform from which to extract sub-samples. The piston is rotated around the threaded-rod at calibrated intervals and gently pushes the sediment out the top of the core tube. The sediment is then isolated into the sampling collar and placed into an appropriate sampling vessel (e.g., jar or bag). This method also preserves the unconsolidated samples (i.e., high pore water content) at the surface, providing a consistent sampling volume. This mm scale extrusion method was applied to cores collected in the northern Gulf of Mexico following the Deepwater Horizon submarine oil release. Evidence suggests that it is necessary to sample at the mm scale to fully characterize events that occur on the monthly time-scale for continental slope sediments. PMID:27585268

Sediment Core Extrusion Method at Millimeter Resolution Using a Calibrated, Threaded-rod.

PubMed

Schwing, Patrick T; Romero, Isabel C; Larson, Rebekka A; O'Malley, Bryan J; Fridrik, Erika E; Goddard, Ethan A; Brooks, Gregg R; Hastings, David W; Rosenheim, Brad E; Hollander, David J; Grant, Guy; Mulhollan, Jim

2016-08-17

Aquatic sediment core subsampling is commonly performed at cm or half-cm resolution. Depending on the sedimentation rate and depositional environment, this resolution provides records at the annual to decadal scale, at best. An extrusion method, using a calibrated, threaded-rod is presented here, which allows for millimeter-scale subsampling of aquatic sediment cores of varying diameters. Millimeter scale subsampling allows for sub-annual to monthly analysis of the sedimentary record, an order of magnitude higher than typical sampling schemes. The extruder consists of a 2 m aluminum frame and base, two core tube clamps, a threaded-rod, and a 1 m piston. The sediment core is placed above the piston and clamped to the frame. An acrylic sampling collar is affixed to the upper 5 cm of the core tube and provides a platform from which to extract sub-samples. The piston is rotated around the threaded-rod at calibrated intervals and gently pushes the sediment out the top of the core tube. The sediment is then isolated into the sampling collar and placed into an appropriate sampling vessel (e.g., jar or bag). This method also preserves the unconsolidated samples (i.e., high pore water content) at the surface, providing a consistent sampling volume. This mm scale extrusion method was applied to cores collected in the northern Gulf of Mexico following the Deepwater Horizon submarine oil release. Evidence suggests that it is necessary to sample at the mm scale to fully characterize events that occur on the monthly time-scale for continental slope sediments.

SPRUCE Peat Physical and Chemical Characteristics from Experimental Plot Cores, 2012

DOE Data Explorer

Iversen, C. M. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hanson, P. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Brice, D. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Phillips, J. R. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; McFarlane, K. J. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Hobbie, E. A. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.; Kolka, R. K. [Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A.

2012-01-01

This data set reports the results of physical and chemical analyses of peat core samples from the SPRUCE experimental study plots located in the S1-Bog. On August 13-15, 2012, a team of SPRUCE investigators and collaborators collected core samples of peat in the SPRUCE experimental plots. The goal was to characterize the biological, physical, and chemical characteristics of peat, and how those characteristics changed throughout the depth profile of the bog, prior to the initialization of the SPRUCE experimental warming and CO2 treatments. Cores were collected from 16 experimental plots; samples were collected from the hummock and hollow surfaces to depths of 200-300 cm in defined increments. Three replicate cores were collected from both hummock and hollow locations in each plot. The coring locations within each plot were mapped

CT Scans of Cores Metadata, Barrow, Alaska 2015

DOE Data Explorer

Katie McKnight; Tim Kneafsey; Craig Ulrich

2015-03-11

Individual ice cores were collected from Barrow Environmental Observatory in Barrow, Alaska, throughout 2013 and 2014. Cores were drilled along different transects to sample polygonal features (i.e. the trough, center and rim of high, transitional and low center polygons). Most cores were drilled around 1 meter in depth and a few deep cores were drilled around 3 meters in depth. Three-dimensional images of the frozen cores were constructed using a medical X-ray computed tomography (CT) scanner. TIFF files can be uploaded to ImageJ (an open-source imaging software) to examine soil structure and densities within each core.

Family and infant characteristics associated with timing of core and non-core food introduction in early childhood

PubMed Central

Schrempft, Stephanie; van Jaarsveld, Cornelia H.M.; Fisher, Abigail; Wardle, Jane

2013-01-01

Objective To identify family and infant characteristics associated with timing of introduction of two food types: core foods (nutrient-dense) and non-core foods (nutrient-poor) in a population-based sample of mothers and infants. Method Participants were 1861 mothers and infants from the Gemini twin birth cohort (one child per family). Family and infant characteristics were assessed when the infants were around 8 months old. Timing of introducing core and non-core foods was assessed at 8 and 15 months. As the distributions of timing were skewed, three similar-sized groups were created for each food type: earlier (core: 1–4 months; non-core: 3–8 months), average (core: 5 months; non-core: 9–10 months), and later introduction (core: 6–12 months; non-core: 11–18 months). Ordinal logistic regression was used to examine predictors of core and non-core food introduction, with bootstrapping to test for differences between the core and non-core models. Results Younger maternal age, lower education level, and higher maternal BMI were associated with earlier core and non-core food introduction. Not breastfeeding for at least 3 months and higher birth weight were specifically associated with earlier introduction of core foods. Having older children was specifically associated with earlier introduction of non-core foods. Conclusion There are similarities and differences in the characteristics associated with earlier introduction of core and non-core foods. Successful interventions may require a combination of approaches to target both food types. PMID:23486509

A Mars Sample Return Sample Handling System

NASA Technical Reports Server (NTRS)

Wilson, David; Stroker, Carol

2013-01-01

We present a sample handling system, a subsystem of the proposed Dragon landed Mars Sample Return (MSR) mission [1], that can return to Earth orbit a significant mass of frozen Mars samples potentially consisting of: rock cores, subsurface drilled rock and ice cuttings, pebble sized rocks, and soil scoops. The sample collection, storage, retrieval and packaging assumptions and concepts in this study are applicable for the NASA's MPPG MSR mission architecture options [2]. Our study assumes a predecessor rover mission collects samples for return to Earth to address questions on: past life, climate change, water history, age dating, understanding Mars interior evolution [3], and, human safety and in-situ resource utilization. Hence the rover will have "integrated priorities for rock sampling" [3] that cover collection of subaqueous or hydrothermal sediments, low-temperature fluidaltered rocks, unaltered igneous rocks, regolith and atmosphere samples. Samples could include: drilled rock cores, alluvial and fluvial deposits, subsurface ice and soils, clays, sulfates, salts including perchlorates, aeolian deposits, and concretions. Thus samples will have a broad range of bulk densities, and require for Earth based analysis where practical: in-situ characterization, management of degradation such as perchlorate deliquescence and volatile release, and contamination management. We propose to adopt a sample container with a set of cups each with a sample from a specific location. We considered two sample cups sizes: (1) a small cup sized for samples matching those submitted to in-situ characterization instruments, and, (2) a larger cup for 100 mm rock cores [4] and pebble sized rocks, thus providing diverse samples and optimizing the MSR sample mass payload fraction for a given payload volume. We minimize sample degradation by keeping them frozen in the MSR payload sample canister using Peltier chip cooling. The cups are sealed by interference fitted heat activated memory

INNOVATIVE TECHNOLOGY EVALUATION REPORT, SEDIMENT SAMPLING TECHNOLOGY, ART'S MANUFACTURING, SPLIT CORE SAMPLER FOR SUBMERGED SEDIMENTS

EPA Science Inventory

The Split Core Sampler for Submerged Sediments (Split Core Sampler) designed and fabricated by Arts Manufacturing & Supply, Inc., was demonstrated under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation Program in April and May 1999 at ...

Design and testing of coring bits on drilling lunar rock simulant

NASA Astrophysics Data System (ADS)

Li, Peng; Jiang, Shengyuan; Tang, Dewei; Xu, Bo; Ma, Chao; Zhang, Hui; Qin, Hongwei; Deng, Zongquan

2017-02-01

Coring bits are widely utilized in the sampling of celestial bodies, and their drilling behaviors directly affect the sampling results and drilling security. This paper introduces a lunar regolith coring bit (LRCB), which is a key component of sampling tools for lunar rock breaking during the lunar soil sampling process. We establish the interaction model between the drill bit and rock at a small cutting depth, and the two main influential parameters (forward and outward rake angles) of LRCB on drilling loads are determined. We perform the parameter screening task of LRCB with the aim to minimize the weight on bit (WOB). We verify the drilling load performances of LRCB after optimization, and the higher penetrations per revolution (PPR) are, the larger drilling loads we gained. Besides, we perform lunar soil drilling simulations to estimate the efficiency on chip conveying and sample coring of LRCB. The results of the simulation and test are basically consistent on coring efficiency, and the chip removal efficiency of LRCB is slightly lower than HIT-H bit from simulation. This work proposes a method for the design of coring bits in subsequent extraterrestrial explorations.

Preserving Geological Samples and Metadata from Polar Regions

NASA Astrophysics Data System (ADS)

Grunow, A.; Sjunneskog, C. M.

2011-12-01

The Office of Polar Programs at the National Science Foundation (NSF-OPP) has long recognized the value of preserving earth science collections due to the inherent logistical challenges and financial costs of collecting geological samples from Polar Regions. NSF-OPP established two national facilities to make Antarctic geological samples and drill cores openly and freely available for research. The Antarctic Marine Geology Research Facility (AMGRF) at Florida State University was established in 1963 and archives Antarctic marine sediment cores, dredge samples and smear slides along with ship logs. The United States Polar Rock Repository (USPRR) at Ohio State University was established in 2003 and archives polar rock samples, marine dredges, unconsolidated materials and terrestrial cores, along with associated materials such as field notes, maps, raw analytical data, paleomagnetic cores, thin sections, microfossil mounts, microslides and residues. The existence of the AMGRF and USPRR helps to minimize redundant sample collecting, lessen the environmental impact of doing polar field work, facilitates field logistics planning and complies with the data sharing requirement of the Antarctic Treaty. USPRR acquires collections through donations from institutions and scientists and then makes these samples available as no-cost loans for research, education and museum exhibits. The AMGRF acquires sediment cores from US based and international collaboration drilling projects in Antarctica. Destructive research techniques are allowed on the loaned samples and loan requests are accepted from any accredited scientific institution in the world. Currently, the USPRR has more than 22,000 cataloged rock samples available to scientists from around the world. All cataloged samples are relabeled with a USPRR number, weighed, photographed and measured for magnetic susceptibility. Many aspects of the sample metadata are included in the database, e.g. geographical location, sample

A Comparison of Increment Core Sampling for Estimating Tree Specific Gravity

Treesearch

Michael A. Taras; Harold E. Wadlgren

1963-01-01

Increment cores have been used to evaluate such tree characteristics as age, rate of growth, percentage of various types of tissue, chemical composition, and density. Of the wood characteristics listed, density has come to be of considerable interest to numerous researchers, since it is highly correlated with the strength properties, workability, and weight of wood....

Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope: Coring operations, core sedimentology, and lithostratigraphy

USGS Publications Warehouse

Rose, K.; Boswell, R.; Collett, T.

2011-01-01

In February 2007, BP Exploration (Alaska), the U.S. Department of Energy, and the U.S. Geological Survey completed the BPXA-DOE-USGS Mount Elbert Gas Hydrate Stratigraphic Test Well (Mount Elbert well) in the Milne Point Unit on the Alaska North Slope. The program achieved its primary goals of validating the pre-drill estimates of gas hydrate occurrence and thickness based on 3-D seismic interpretations and wireline log correlations and collecting a comprehensive suite of logging, coring, and pressure testing data. The upper section of the Mount Elbert well was drilled through the base of ice-bearing permafrost to a casing point of 594??m (1950??ft), approximately 15??m (50??ft) above the top of the targeted reservoir interval. The lower portion of the well was continuously cored from 606??m (1987??ft) to 760??m (2494??ft) and drilled to a total depth of 914??m. Ice-bearing permafrost extends to a depth of roughly 536??m and the base of gas hydrate stability is interpreted to extend to a depth of 870??m. Coring through the targeted gas hydrate bearing reservoirs was completed using a wireline-retrievable system. The coring program achieved 85% recovery of 7.6??cm (3??in) diameter core through 154??m (504??ft) of the hole. An onsite team processed the cores, collecting and preserving approximately 250 sub-samples for analyses of pore water geochemistry, microbiology, gas chemistry, petrophysical analysis, and thermal and physical properties. Eleven samples were immediately transferred to either methane-charged pressure vessels or liquid nitrogen for future study of the preserved gas hydrate. Additional offsite sampling, analyses, and detailed description of the cores were also conducted. Based on this work, one lithostratigraphic unit with eight subunits was identified across the cored interval. Subunits II and Va comprise the majority of the reservoir facies and are dominantly very fine to fine, moderately sorted, quartz, feldspar, and lithic fragment-bearing to

Calculation of elastic properties in lower part of the Kola borehole from bulk chemical compositions of core samples

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

Babeyko, A.Yu.; Sobolev, S.V.; Sinelnikov, E.D.

1994-09-01

In-situ elastic properties in deep boreholes are controlled by several factors, mainly by lithology, petrofabric, fluid-filled cracks and pores. In order to separate the effects of different factors it is useful to extract lithology-controlled part from observed in-situ velocities. For that purpose we calculated mineralogical composition and isotropic crack-free elastic properties in the lower part of the Kola borehole from bulk chemical compositions of core samples. We use a new technique of petrophysical modeling based on thermodynamic approach. The reasonable accuracy of the modeling is confirmed by comparison with the observations of mineralogical composition and laboratory measurements of density andmore » elastic wave velocities in upper crustal crystalline rocks at high confining pressure. Calculations were carried out for 896 core samples from the depth segment of 6840-10535m. Using these results we estimate density and crack-free isotropic elastic properties of 554 lithology-defined layers composing this depth segment. Average synthetic P-wave velocity appears to be 2.7% higher than the velocity from Vertical Seismic Profiling (VSP), and 5% higher than sonic log velocity. Average synthetic S-wave velocity is 1.4% higher than that from VSP. These differences can be explained by superposition of effects of fabric-related anisotropy, cracks aligned parallel to the foliation plain, and randomly oriented cracks, with the effects of cracks being the predominant control. Low sonic log velocities are likely caused by drilling-induced cracking (hydrofractures) in the borehole walls. The calculated synthetic density and velocity cross-sections can be used for much more detailed interpretations, for which, however, new, more detailed and reliable seismic data are required.« less

Estimating the spatial distribution of soil organic matter density and geochemical properties in a polygonal shaped Arctic Tundra using core sample analysis and X-ray computed tomography

NASA Astrophysics Data System (ADS)

Soom, F.; Ulrich, C.; Dafflon, B.; Wu, Y.; Kneafsey, T. J.; López, R. D.; Peterson, J.; Hubbard, S. S.

2016-12-01

The Arctic tundra with its permafrost dominated soils is one of the regions most affected by global climate change, and in turn, can also influence the changing climate through biogeochemical processes, including greenhouse gas release or storage. Characterization of shallow permafrost distribution and characteristics are required for predicting ecosystem feedbacks to a changing climate over decadal to century timescales, because they can drive active layer deepening and land surface deformation, which in turn can significantly affect hydrological and biogeochemical responses, including greenhouse gas dynamics. In this study, part of the Next-Generation Ecosystem Experiment (NGEE-Arctic), we use X-ray computed tomography (CT) to estimate wet bulk density of cores extracted from a field site near Barrow AK, which extend 2-3m through the active layer into the permafrost. We use multi-dimensional relationships inferred from destructive core sample analysis to infer organic matter density, dry bulk density and ice content, along with some geochemical properties from nondestructive CT-scans along the entire length of the cores, which was not obtained by the spatially limited destructive laboratory analysis. Multi-parameter cross-correlations showed good agreement between soil properties estimated from CT scans versus properties obtained through destructive sampling. Soil properties estimated from cores located in different types of polygons provide valuable information about the vertical distribution of soil and permafrost properties as a function of geomorphology.

Advanced core-analyses for subsurface characterization

NASA Astrophysics Data System (ADS)

Pini, R.

2017-12-01

The heterogeneity of geological formations varies over a wide range of length scales and represents a major challenge for predicting the movement of fluids in the subsurface. Although they are inherently limited in the accessible length-scale, laboratory measurements on reservoir core samples still represent the only way to make direct observations on key transport properties. Yet, properties derived on these samples are of limited use and should be regarded as sample-specific (or `pseudos'), if the presence of sub-core scale heterogeneities is not accounted for in data processing and interpretation. The advent of imaging technology has significantly reshaped the landscape of so-called Special Core Analysis (SCAL) by providing unprecedented insight on rock structure and processes down to the scale of a single pore throat (i.e. the scale at which all reservoir processes operate). Accordingly, improved laboratory workflows are needed that make use of such wealth of information by e.g., referring to the internal structure of the sample and in-situ observations, to obtain accurate parameterisation of both rock- and flow-properties that can be used to populate numerical models. We report here on the development of such workflow for the study of solute mixing and dispersion during single- and multi-phase flows in heterogeneous porous systems through a unique combination of two complementary imaging techniques, namely X-ray Computed Tomography (CT) and Positron Emission Tomography (PET). The experimental protocol is applied to both synthetic and natural porous media, and it integrates (i) macroscopic observations (tracer effluent curves), (ii) sub-core scale parameterisation of rock heterogeneities (e.g., porosity, permeability and capillary pressure), and direct 3D observation of (iii) fluid saturation distribution and (iv) the dynamic spreading of the solute plumes. Suitable mathematical models are applied to reproduce experimental observations, including both 1D and 3D

A Model of the Chicxulub Impact Basin Based on Evaluation of Geophysical Data, Well Logs, and Drill Core Samples

NASA Technical Reports Server (NTRS)

Sharpton, Virgil L.; Marin, Luis E.; Carney, John D.; Lee, Scott; Ryder, Graham; Schuraytz, Benjamin C.; Sikora, Paul; Spudis, Paul D.

1996-01-01

Abundant evidence now shows that the buried Chicxulub structure in northern Yucatan, Mexico, is indeed the intensely sought-after source of the ejecta found world-wide at the Cretaceous-Tertiary (K/T) boundary. In addition to large-scale concentric patterns in gravity and magnetic data over the structure, recent analyses of drill-core samples reveal a lithological assemblage similar to that observed at other terrestrial craters. This assemblage comprises suevite breccias, ejecta deposit breccias (Bunte Breccia equivalents), fine-grained impact melt rocks, and melt-matrix breccias. All these impact-produced lithologies contain diagnostic evidence of shock metamorphism, including planar deformation features in quartz, feldspar, and zircons; diaplectic glasses of quartz and feldspar; and fused mineral melts and whole-rock melts. In addition, elevated concentrations of Ir, Re, and Os, in meteoritic relative proportions, have been detected in some melt-rock samples from the center of the structure. Isotopic analyses, magnetization of melt-rock samples, and local stratigraphic constraints identify this crater as the source of K/T boundary deposits.

Gravity or turbulence? IV. Collapsing cores in out-of-virial disguise

NASA Astrophysics Data System (ADS)

Ballesteros-Paredes, Javier; Vázquez-Semadeni, Enrique; Palau, Aina; Klessen, Ralf S.

2018-06-01

We study the dynamical state of massive cores by using a simple analytical model, an observational sample, and numerical simulations of collapsing massive cores. From the analytical model, we find that cores increase their column density and velocity dispersion as they collapse, resulting in a time evolution path in the Larson velocity dispersion-size diagram from large sizes and small velocity dispersions to small sizes and large velocity dispersions, while they tend to equipartition between gravity and kinetic energy. From the observational sample, we find that: (a) cores with substantially different column densities in the sample do not follow a Larson-like linewidth-size relation. Instead, cores with higher column densities tend to be located in the upper-left corner of the Larson velocity dispersion σv, 3D-size R diagram, a result explained in the hierarchical and chaotic collapse scenario. (b) Cores appear to have overvirial values. Finally, our numerical simulations reproduce the behavior predicted by the analytical model and depicted in the observational sample: collapsing cores evolve towards larger velocity dispersions and smaller sizes as they collapse and increase their column density. More importantly, however, they exhibit overvirial states. This apparent excess is due to the assumption that the gravitational energy is given by the energy of an isolated homogeneous sphere. However, such excess disappears when the gravitational energy is correctly calculated from the actual spatial mass distribution. We conclude that the observed energy budget of cores is consistent with their non-thermal motions being driven by their self-gravity and in the process of dynamical collapse.

PTEN loss and chromosome 8 alterations in Gleason grade 3 prostate cancer cores predicts the presence of un-sampled grade 4 tumor: implications for active surveillance.

PubMed

Trock, Bruce J; Fedor, Helen; Gurel, Bora; Jenkins, Robert B; Knudsen, B S; Fine, Samson W; Said, Jonathan W; Carter, H Ballentine; Lotan, Tamara L; De Marzo, Angelo M

2016-07-01

Men who enter active surveillance because their biopsy exhibits only Gleason grade 3 (G3) frequently have higher grade tumor missed by biopsy. Thus, biomarkers are needed that, when measured on G3 tissue, can predict the presence of higher grade tumor in the whole prostate. We evaluated whether PTEN loss, chromosome 8q gain (MYC) and/or 8p loss (LPL) measured only on G3 cores is associated with un-sampled G4 tumor. A tissue microarray was constructed of prostatectomy tissue from patients whose prostates exhibited only Gleason score 3+3, only 3+4 or only 4+3 tumor (n=50 per group). Cores sampled only from areas of G3 were evaluated for PTEN loss by immunohistochemistry, and PTEN deletion, LPL/8p loss and MYC/8q gain by fluorescence in situ hybridization. Biomarker results were compared between Gleason score 6 vs 7 tumors using conditional logistic regression. PTEN protein loss, odds ratio=4.99, P=0.033; MYC/8q gain, odds ratio=5.36, P=0.010; and LPL/8p loss, odds ratio=3.96, P=0.003 were significantly more common in G3 cores derived from Gleason 7 vs Gleason 6 tumors. PTEN gene deletion was not statistically significant. Associations were stronger comparing Gleason 4+3 vs 6 than for Gleason 3+4 vs 6. MYC/8q gain, LPL/8p loss and PTEN protein loss measured in G3 tissue microarray cores strongly differentiate whether the core comes from a Gleason 6 or Gleason 7 tumor. If validated to predict upgrading from G3 biopsy to prostatectomy these biomarkers could reduce the likelihood of enrolling high-risk men and facilitate safe patient selection for active surveillance.

City Core - detecting the anthropocene in urban lake cores

NASA Astrophysics Data System (ADS)

Kjaer, K. H.; Ilsøe, P.; Andresen, C. S.; Rasmussen, P.; Andersen, T. J.; Frei, R.; Schreiber, N.; Odgaard, B.; Funder, S.; Holm, J. M.; Andersen, K.

2011-12-01

Here, we presents the preliminary results from lake cores taken in ditches associated with the historical fortifications enclosing the oldest - central Copenhagen to achieve new knowledge from sediment deposits related to anthropogenic activities. We have examined sediment cores with X-ray fluorescence (XRF) analyzers to correlate element patterns from urban and industrial emissions. Thus, we aim to track these patterns back in time - long before regular routines of recording of atmospheric environment began around 1978. Furthermore, we compare our data to alternative sources of information in order to constrain and expand the temporal dating limits (approximately 1890) achieved from 210Pb activity. From custom reports and statistic sources, information on imported volumes from coal, metal and oil was obtained and related contaminants from these substances to the sediment archives. Intriguingly, we find a steep increase in import of coal and metals matching the exponential increase of lead and zinc counts from XRF-recordings of the sediment cores. In this finding, we claim to have constrain the initiation of urban industrialization. In order to confirm the age resolution of the lake cores, DNA was extracted from sediments, sedaDNA. Thus we attempt to trace plantation of well documented exotic plants to, for instance, the Botanical Garden. Through extraction and sampling of sedaDNA from these floral and arboreal specimens we intend to locate their strataigraphic horizons in the sediment core. These findings may correlate data back to 1872, when the garden was established on the area of the former fortification. In this line of research, we hope to achieve important supplementary knowledge of sedaDNA-leaching frequencies within freshwater sediments.

THE CORES OF THE Fe K{alpha} LINES IN ACTIVE GALACTIC NUCLEI: AN EXTENDED CHANDRA HIGH ENERGY GRATING SAMPLE

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

Shu, X. W.; Wang, J. X.; Yaqoob, T.

We extend the study of the core of the Fe K{alpha} emission line at {approx}6.4 keV in Seyfert galaxies reported by Yaqoob and Padmanabhan using a larger sample observed by the Chandra high-energy grating (HEG). The sample consists of 82 observations of 36 unique sources with z < 0.3. Whilst heavily obscured active galactic nuclei are excluded from the sample, these data offer some of the highest precision measurements of the peak energy of the Fe K{alpha} line, and the highest spectral resolution measurements of the width of the core of the line in unobscured and moderately obscured (N {submore » H} < 10{sup 23} cm{sup -2}) Seyfert galaxies to date. From an empirical and uniform analysis, we present measurements of the Fe K{alpha} line centroid energy, flux, equivalent width (EW), and intrinsic width (FWHM). The Fe K{alpha} line is detected in 33 sources, and its centroid energy is constrained in 32 sources. In 27 sources, the statistical quality of the data is good enough to yield measurements of the FWHM. We find that the distribution in the line centroid energy is strongly peaked around the value for neutral Fe, with over 80% of the observations giving values in the range 6.38-6.43 keV. Including statistical errors, 30 out of 32 sources ({approx}94%) have a line centroid energy in the range 6.35-6.47 keV. The mean EW, among the observations in which a non-zero lower limit could be measured, was 53 {+-} 3 eV. The mean FWHM from the subsample of 27 sources was 2060 {+-} 230 km s{sup -1}. The mean EW and FWHM are somewhat higher when multiple observations for a given source are averaged. From a comparison with the H{beta} optical emission-line widths (or, for one source, Br{alpha}), we find that there is no universal location of the Fe K{alpha} line-emitting region relative to the optical broad-line region (BLR). In general, a given source may have contributions to the Fe K{alpha} line flux from parsec-scale distances from the putative black hole, down to matter

Resolving Supercritical Orion Cores

NASA Astrophysics Data System (ADS)

Li, Di; Chapman, N.; Goldsmith, P.; Velusamy, T.

2009-01-01

The theoretical framework for high mass star formation (HMSF) is unclear. Observations reveal a seeming dichotomy between high- and low-mass star formation, with HMSF occurring only in Giant Molecular Clouds (GMC), mostly in clusters, and with higher star formation efficiencies than low-mass star formation. One crucial constraint to any theoretical model is the dynamical state of massive cores, in particular, whether a massive core is in supercritical collapse. Based on the mass-size relation of dust emission, we select likely unstable targets from a sample of massive cores (Li et al. 2007 ApJ 655, 351) in the nearest GMC, Orion. We have obtained N2H+ (1-0) maps using CARMA with resolution ( 2.5", 0.006 pc) significantly better than existing observations. We present observational and modeling results for ORI22. By revealing the dynamic structure down to Jeans scale, CARMA data confirms the dominance of gravity over turbulence in this cores. This work was performed by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Three Types of Earth's Inner Core Boundary

NASA Astrophysics Data System (ADS)

Tian, D.; Wen, L.

2017-12-01

The Earth's inner core boundary (ICB) is the site where the liquid outer core solidifies and the solid inner core grows. Thus, the fine-scale structure of the ICB is important for our understanding of the thermo-compositional state of the Earth's core. In this study, we collect a large set of seismic records with high-quality pre-critical PKiKP and PcP phase pairs, recorded by two dense seismic arrays, Hi-net in Japan and USArray in US. This dataset samples the ICB regions beneath East Asia, Mexico and the Bering Sea. We use differential travel times, amplitude ratios and waveform differences between PKiKP and PcP phases to constrain fine-scale structure of the ICB. The sampled ICB can be grouped into three types based on their seismic characteristics: (1) a simple ICB with a flat and sharp boundary, (2) a bumpy ICB with topographic height changes of 10 km, and (3) a localized mushy ICB with laterally varying thicknesses of 4-8 km. The laterally varying fine-scale structure of the ICB indicates existence of complex small-scale forces at the surface and a laterally varying solidification process of the inner core due to lateral variation of thermo-compositional condition near the ICB.

Visible-Near Infrared Point Spectrometry of Drill Core Samples from Río Tinto, Spain: Results from the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) Drilling Exercise

NASA Astrophysics Data System (ADS)

Sutter, Brad; Brown, Adrian J.; Stoker, Carol R.

2008-10-01

Sampling of subsurface rock may be required to detect evidence of past biological activity on Mars. The Mars Astrobiology Research and Technology Experiment (MARTE) utilized the Río Tinto region, Spain, as a Mars analog site to test dry drilling technologies specific to Mars that retrieve subsurface rock for biological analysis. This work examines the usefulness of visible-near infrared (VNIR) (450-1000 nm) point spectrometry to characterize ferric iron minerals in core material retrieved during a simulated Mars drilling mission. VNIR spectrometry can indicate the presence of aqueously precipitated ferric iron minerals and, thus, determine whether biological analysis of retrieved rock is warranted. Core spectra obtained during the mission with T1 (893-897 nm) and T2 (644-652 nm) features indicate goethite-dominated samples, while relatively lower wavelength T1 (832-880 nm) features indicate hematite. Hematite/goethite molar ratios varied from 0 to 1.4, and within the 880-898 nm range, T1 features were used to estimate hematite/goethite molar ratios. Post-mission X-ray analysis detected phyllosilicates, which indicates that examining beyond the VNIR (e.g., shortwave infrared, 1000-2500 nm) will enhance the detection of other minerals formed by aqueous processes. Despite the limited spectral range of VNIR point spectrometry utilized in the MARTE Mars drilling simulation project, ferric iron minerals could be identified in retrieved core material, and their distribution served to direct core subsampling for biological analysis.

Visible-near infrared point spectrometry of drill core samples from Río Tinto, Spain: results from the 2005 Mars Astrobiology Research and Technology Experiment (MARTE) drilling exercise.

PubMed

Sutter, Brad; Brown, Adrian J; Stoker, Carol R

2008-10-01

Sampling of subsurface rock may be required to detect evidence of past biological activity on Mars. The Mars Astrobiology Research and Technology Experiment (MARTE) utilized the Río Tinto region, Spain, as a Mars analog site to test dry drilling technologies specific to Mars that retrieve subsurface rock for biological analysis. This work examines the usefulness of visible-near infrared (VNIR) (450-1000 nm) point spectrometry to characterize ferric iron minerals in core material retrieved during a simulated Mars drilling mission. VNIR spectrometry can indicate the presence of aqueously precipitated ferric iron minerals and, thus, determine whether biological analysis of retrieved rock is warranted. Core spectra obtained during the mission with T1 (893-897 nm) and T2 (644-652 nm) features indicate goethite-dominated samples, while relatively lower wavelength T1 (832-880 nm) features indicate hematite. Hematite/goethite molar ratios varied from 0 to 1.4, and within the 880-898 nm range, T1 features were used to estimate hematite/goethite molar ratios. Post-mission X-ray analysis detected phyllosilicates, which indicates that examining beyond the VNIR (e.g., shortwave infrared, 1000-2500 nm) will enhance the detection of other minerals formed by aqueous processes. Despite the limited spectral range of VNIR point spectrometry utilized in the MARTE Mars drilling simulation project, ferric iron minerals could be identified in retrieved core material, and their distribution served to direct core subsampling for biological analysis.

A long-lived lunar core dynamo.

PubMed

Shea, Erin K; Weiss, Benjamin P; Cassata, William S; Shuster, David L; Tikoo, Sonia M; Gattacceca, Jérôme; Grove, Timothy L; Fuller, Michael D

2012-01-27

Paleomagnetic measurements indicate that a core dynamo probably existed on the Moon 4.2 billion years ago. However, the subsequent history of the lunar core dynamo is unknown. Here we report paleomagnetic, petrologic, and (40)Ar/(39)Ar thermochronometry measurements on the 3.7-billion-year-old mare basalt sample 10020. This sample contains a high-coercivity magnetization acquired in a stable field of at least ~12 microteslas. These data extend the known lifetime of the lunar dynamo by 500 million years. Such a long-lived lunar dynamo probably required a power source other than thermochemical convection from secular cooling of the lunar interior. The inferred strong intensity of the lunar paleofield presents a challenge to current dynamo theory.

On the Evolution of the Cores of Radio Sources and Their Extended Radio Emission

NASA Astrophysics Data System (ADS)

Yuan, Zunli; Wang, Jiancheng

2012-01-01

The work in this paper aims at determining the evolution and possible co-evolution of radio-loud active galactic nuclei (AGNs) and their cores via their radio luminosity functions (i.e., total and core RLFs, respectively). Using a large combined sample of 1063 radio-loud AGNs selected at low radio frequency, we investigate the RLF at 408 MHz of steep-spectrum radio sources. Our results support a luminosity-dependent evolution. Using core flux density data of the complete sample 3CRR, we investigate the core RLF at 5.0 GHz. Based on the combined sample with incomplete core flux data, we also estimate the core RLF using a modified factor of completeness. Both results are consistent and show that the comoving number density of radio cores displays a persistent decline with redshift, implying a negative density evolution. We find that the core RLF is obviously different from the total RLF at the 408 MHz band which is mainly contributed by extended lobes, implying that the cores and extended lobes could not be co-evolving at radio emission.

Successive measurements of streaming potential and electroosmotic pressure with the same core-holder

NASA Astrophysics Data System (ADS)

Yin, Chenggang; Hu, Hengshan; Yu, Chunhao; Wang, Jun

2018-05-01

Successive measurements of the streaming potential and electroosmotic pressure of each core sample are important for understanding the mechanisms of electrokinetic effects. In previous studies, one plug of the core-holder needs to be replaced in these two experiments, which causes the change of the fluid parameters and the boundary conditions in the core. We design a new core-holder to permit successive experiments without plug replacement, which ensures the consistency of the measurement environment. A two-direction harmonic pressure-driving source is accordingly designed. Using this new equipment, electrokinetic experiments conducted ten core samples at 0.4 mol/L NaCl solution. The results show good agreement between the electrokinetically deduced permeability and premeasured gas permeability. For high salinity saturated samples, the permeability can be inverted from electroosmotic effect instead of the streaming potential.

Physical property data from the ICDP-USGS Eyreville cores A and B, Chesapeake Bay impact structure, Virginia, USA, acquired using a multisensor core logger

USGS Publications Warehouse

Pierce, H.A.; Murray, J.B.

2009-01-01

The International Continental Scientific Drilling Program (ICDP) and the U.S. Geological Survey (USGS) drilled three core holes to a composite depth of 1766 m within the moat of the Chesapeake Bay impact structure. Core recovery rates from the drilling were high (??90%), but problems with core hole collapse limited the geophysical downhole logging to natural-gamma and temperature logs. To supplement the downhole logs, ??5% of the Chesapeake Bay impact structure cores was processed through the USGS GeoTek multisensor core logger (MSCL) located in Menlo Park, California. The measured physical properties included core thickness (cm), density (g cm-3), P-wave velocity (m s-1), P-wave amplitude (%), magnetic susceptibility (cgs), and resistivity (ohm-m). Fractional porosity was a secondary calculated property. The MSCL data-sampling interval for all core sections was 1 cm longitudinally. Photos of each MSCL sampled core section were imbedded with the physical property data for direct comparison. These data have been used in seismic, geologic, thermal history, magnetic, and gravity models of the Chesapeake Bay impact structure. Each physical property curve has a unique signature when viewed over the full depth of the Chesapeake Bay impact structure core holes. Variations in the measured properties reflect differences in pre-impact target-rock lithologies and spatial variations in impact-related deformation during late-stage crater collapse and ocean resurge. ?? 2009 The Geological Society of America.

Monitoring of NMR porosity changes in the full-size core salvage through the drying process

NASA Astrophysics Data System (ADS)

Fattakhov, Artur; Kosarev, Victor; Doroginitskii, Mikhail; Skirda, Vladimir

2015-04-01

Currently the principle of nuclear magnetic resonance (NMR) is one of the most popular technologies in the field of borehole geophysics and core analysis. Results of NMR studies allow to calculate the values of the porosity and permeability of sedimentary rocks with sufficient reliability. All standard tools for the study of core salvage on the basis of NMR have significant limitations: there is considered only long relaxation times corresponding to the mobile formation fluid. Current trends in energy obligate to move away from conventional oil to various alternative sources of energy. One of these sources are deposits of bitumen and high-viscosity oil. In Kazan (Volga Region) Federal University (Russia) there was developed a mobile unit for the study of the full-length core salvage by the NMR method ("NMR-Core") together with specialists of "TNG-Group" (a company providing maintenance services to oil companies). This unit is designed for the study of core material directly on the well, after removing it from the core receiver. The maximum diameter of the core sample may be up to 116 mm, its length (or length of the set of samples) may be up to 1000 mm. Positional precision of the core sample relative to the measurement system is 1 mm, and the spatial resolution along the axis of the core is 10 mm. Acquisition time of the 1 m core salvage varies depending on the mode of research and is at least 20 minutes. Furthermore, there is implemented a special investigation mode of the core samples with super small relaxation times (for example, heavy oil) is in the tool. The aim of this work is tracking of the NMR porosity changes in the full-size core salvage in time. There was used a water-saturated core salvage from the shallow educational well as a sample. The diameter of the studied core samples is 93 mm. There was selected several sections length of 1m from the 200-meter coring interval. The studied core samples are being measured several times. The time interval

Development of coring procedures applied to Si, CdTe, and CIGS solar panels

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

Moutinho, H. R.; Johnston, S.; To, B.

Most of the research on the performance and degradation of photovoltaic modules is based on macroscale measurements of device parameters such as efficiency, fill factor, open-circuit voltage, and short-circuit current. Our goal is to develop the capabilities to allow us to study the degradation of these parameters in the micro- and nanometer scale and to relate our results to performance parameters. To achieve this objective, the first step is to be able to access small samples from specific areas of the solar panels without changing the properties of the material. In this paper, we describe two coring procedures that wemore » developed and applied to Si, CIGS, and CdTe solar panels. In the first procedure, we cored full samples, whereas in the second we performed a partial coring that keeps the tempered glass intact. The cored samples were analyzed by different analytical techniques before and after coring, at the same locations, and no damage during the coring procedure was observed.« less

Development of coring procedures applied to Si, CdTe, and CIGS solar panels

DOE PAGES

Moutinho, H. R.; Johnston, S.; To, B.; ...

2018-01-04

Most of the research on the performance and degradation of photovoltaic modules is based on macroscale measurements of device parameters such as efficiency, fill factor, open-circuit voltage, and short-circuit current. Our goal is to develop the capabilities to allow us to study the degradation of these parameters in the micro- and nanometer scale and to relate our results to performance parameters. To achieve this objective, the first step is to be able to access small samples from specific areas of the solar panels without changing the properties of the material. In this paper, we describe two coring procedures that wemore » developed and applied to Si, CIGS, and CdTe solar panels. In the first procedure, we cored full samples, whereas in the second we performed a partial coring that keeps the tempered glass intact. The cored samples were analyzed by different analytical techniques before and after coring, at the same locations, and no damage during the coring procedure was observed.« less

A wet, heterogeneous lunar interior: Lower mantle and core dynamo evolution

NASA Astrophysics Data System (ADS)

Evans, A. J.; Zuber, M. T.; Weiss, B. P.; Tikoo, S. M.

2014-05-01

While recent analyses of lunar samples indicate the Moon had a core dynamo from at least 4.2-3.56 Ga, mantle convection models of the Moon yield inadequate heat flux at the core-mantle boundary to sustain thermal core convection for such a long time. Past investigations of lunar dynamos have focused on a generally homogeneous, relatively dry Moon, while an initial compositionally stratified mantle is the expected consequence of a postaccretionary lunar magma ocean. Furthermore, recent re-examination of Apollo samples and geophysical data suggests that the Moon contains at least some regions with high water content. Using a finite element model, we investigate the possible consequences of a heterogeneously wet, compositionally stratified interior for the evolution of the Moon. We find that a postoverturn model of mantle cumulates could result in a core heat flux sufficiently high to sustain a dynamo through 2.5 Ga and a maximum surface, dipolar magnetic field strength of less than 1 μT for a 350-km core and near ˜2 μT for a 450-km core. We find that if water was transported or retained preferentially in the deep interior, it would have played a significant role in transporting heat out of the deep interior and reducing the lower mantle temperature. Thus, water, if enriched in the lower mantle, could have influenced core dynamo timing by over 1.0 Gyr and enhanced the vigor of a lunar core dynamo. Our results demonstrate the plausibility of a convective lunar core dynamo even beyond the period currently indicated by the Apollo samples.

Core Cutting Test with Vertical Rock Cutting Rig (VRCR)

NASA Astrophysics Data System (ADS)

Yasar, Serdar; Osman Yilmaz, Ali

2017-12-01

Roadheaders are frequently used machines in mining and tunnelling, and performance prediction of roadheaders is important for project economics and stability. Several methods were proposed so far for this purpose and, rock cutting tests are the best choice. Rock cutting tests are generally divided into two groups which are namely, full scale rock cutting tests and small scale rock cutting tests. These two tests have some superiorities and deficiencies over themselves. However, in many cases, where rock sampling becomes problematic, small scale rock cutting test (core cutting test) is preferred for performance prediction, since small block samples and core samples can be conducted to rock cutting testing. Common problem for rock cutting tests are that they can be found in very limited research centres. In this study, a new mobile rock cutting testing equipment, vertical rock cutting rig (VRCR) was introduced. Standard testing procedure was conducted on seven rock samples which were the part of a former study on cutting rocks with another small scale rock cutting test. Results showed that core cutting test can be realized successfully with VRCR with the validation of paired samples t-test.

Barium and calcium analyses in sediment cores using µ-XRF core scanners

NASA Astrophysics Data System (ADS)

Acar, Dursun; Çaǧatay, Namık; Genç, S. Can; Eriş, K. Kadir; Sarı, Erol; Uçarkus, Gülsen

2017-04-01

Barium and Ca are used as proxies for organic productivity in paleooceanographic studies. With its heavy atomic weight (137.33 u), barium is easily detectable in small concentrations (several ppm levels) in marine sediments using XRF methods, including the analysis by µ-XRF core scanners. Calcium has an intermediate atomic weight (40.078 u) but is a major element in the earth's crust and in sediments and sedimentary rocks, and hence it is easily detectable by µ-XRF techniques. Normally, µ-XRF elemental analysis of cores are carried out using split half cores or 1-2 cm thich u-channels with an original moisture. Sediment cores show variation in different water content (and porosity) along their length. This in turn results in variation in the XRF counts of the elements and causes error in the elemental concentrations. We tried µ-XRF elemental analysis of split half cores, subsampled as 1 cm thick u-channels with original moisture and 0.3 mm-thin film slices of the core with original wet sample and after air drying with humidity protector mylar film. We found considerable increase in counts of most elements, and in particular for Ba and Ca, when we used 0.3 mm thin film, dried slice. In the case of Ba, the counts increased about three times that of the analysis made with wet and 1 cm thick u-channels. The higher Ba and Ca counts are mainly due to the possible precipitation of Ba as barite and Ca as gypsum from oxidation of Fe-sulphides and the evaporation of pore waters. The secondary barite and gypsum precipitation would be especially serious in unoxic sediment units, such as sapropels, with considerable Fe-sulphides and bio-barite.It is therefore suggested that reseachers should be cautious of such secondary precipitation on core surfaces when analyzing cores that have long been exposed to the atmospheric conditions.

Sulfur in Earth's Mantle and Its Behavior During Core Formation

NASA Technical Reports Server (NTRS)

Chabot, Nancy L.; Righter,Kevin

2006-01-01

The density of Earth's outer core requires that about 5-10% of the outer core be composed of elements lighter than Fe-Ni; proposed choices for the "light element" component of Earth's core include H, C, O, Si, S, and combinations of these elements [e.g. 1]. Though samples of Earth's core are not available, mantle samples contain elemental signatures left behind from the formation of Earth's core. The abundances of siderophile (metal-loving) elements in Earth's mantle have been used to gain insight into the early accretion and differentiation history of Earth, the process by which the core and mantle formed, and the composition of the core [e.g. 2-4]. Similarly, the abundance of potential light elements in Earth's mantle could also provide constraints on Earth's evolution and core composition. The S abundance in Earth's mantle is 250 ( 50) ppm [5]. It has been suggested that 250 ppm S is too high to be due to equilibrium core formation in a high pressure, high temperature magma ocean on early Earth and that the addition of S to the mantle from the subsequent accretion of a late veneer is consequently required [6]. However, this earlier work of Li and Agee [6] did not parameterize the metalsilicate partitioning behavior of S as a function of thermodynamic variables, limiting the different pressure and temperature conditions during core formation that could be explored. Here, the question of explaining the mantle abundance of S is revisited, through parameterizing existing metal-silicate partitioning data for S and applying the parameterization to core formation in Earth.

Synthesis of core-shell molecularly imprinted polymer microspheres by precipitation polymerization for the inline molecularly imprinted solid-phase extraction of thiabendazole from citrus fruits and orange juice samples.

PubMed

Barahona, Francisco; Turiel, Esther; Cormack, Peter A G; Martín-Esteban, Antonio

2011-01-01

In this work, the synthesis of molecularly imprinted polymer microspheres with narrow particle size distributions and core-shell morphology by a two-step precipitation polymerization procedure is described. Polydivinylbenzene (poly DVB-80) core particles were used as seed particles in the production of molecularly imprinted polymer shells by copolymerization of divinylbenzene-80 with methacrylic acid in the presence of thiabendazole (TBZ) and an appropriate porogen. Thereafter, polymer particles were packed into refillable stainless steel HPLC columns used in the development of an inline molecularly imprinted SPE method for the determination of TBZ in citrus fruits and orange juice samples. Under optimized chromatographic conditions, recoveries of TBZ within the range 81.1-106.4%, depending upon the sample, were obtained, with RSDs lower than 10%. This novel method permits the unequivocal determination of TBZ in the samples under study, according to the maximum residue levels allowed within Europe, in less than 20 min and without any need for a clean-up step in the analytical protocol. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diagnostic accuracy of 22/25-gauge core needle in endoscopic ultrasound-guided sampling: systematic review and meta-analysis.

PubMed

Oh, Hyoung-Chul; Kang, Hyun; Lee, Jae Young; Choi, Geun Joo; Choi, Jung Sik

2016-11-01

To compare the diagnostic accuracy of endoscopic ultrasound-guided core needle aspiration with that of standard fine-needle aspiration by systematic review and meta-analysis. Studies using 22/25-gauge core needles, irrespective of comparison with standard fine needles, were comprehensively reviewed. Pooled sensitivity, specificity, diagnostic odds ratio (DOR), and summary receiver operating characteristic curves for the diagnosis of malignancy were used to estimate the overall diagnostic efficiency. The pooled sensitivity, specificity, and DOR of the core needle for the diagnosis of malignancy were 0.88 (95% confidence interval [CI], 0.84 to 0.90), 0.99 (95% CI, 0.96 to 1), and 167.37 (95% CI, 65.77 to 425.91), respectively. The pooled sensitivity, specificity, and DOR of the standard needle were 0.84 (95% CI, 0.79 to 0.88), 1 (95% CI, 0.97 to 1), and 130.14 (95% CI, 34.00 to 495.35), respectively. The area under the curve of core and standard needle in the diagnosis of malignancy was 0.974 and 0.955, respectively. The core and standard needle were comparable in terms of pancreatic malignancy diagnosis. There was no significant difference in procurement of optimal histologic cores between core and standard needles (risk ratio [RR], 0.545; 95% CI, 0.187 to 1.589). The number of needle passes for diagnosis was significantly lower with the core needle (standardized mean difference, -0.72; 95% CI, -1.02 to -0.41). There were no significant differences in overall complications (RR, 1.26; 95% CI, 0.34 to 4.62) and technical failure (RR, 5.07; 95% CI, 0.68 to 37.64). Core and standard needles were comparable in terms of diagnostic accuracy, technical performance, and safety profile.

The Concentration of Severely Disturbed CMI in a Core Urban Area.

ERIC Educational Resources Information Center

Shern, David; Dilts, Stephen L.

1987-01-01

Conducted two needs assessment studies of chronically mentally ill (CMI). Examined differential concentration of CMI persons in areas of Colorado, finding a disproportionate concentration on CMI persons in core urban area of Denver. Comparison of core urban clients to national sample revealed that Denver's core urban CMI population was severely…

Cyclical Changes in the Pleistocene Climate from an Analysis of Biogenic Silica in a Bottom Sediment Core Sample of Lake Baikal

NASA Astrophysics Data System (ADS)

Dergachev, V. A.; Dmitriev, P. B.

2017-12-01

An inhomogeneous time series of measurements of the percentage content of biogenic silica in the samples of joint cores BDP-96-1 and BDP-96-2 from the bottom of Lake Baikal drilled at a depth of 321 m under water has been analyzed. The composite depth of cores is 77 m, which covers the Pleistocene Epoch to 1.8 Ma. The time series was reduced to a regular form with a time step of 1 kyr, which allowed 16 distinct quasi-periodic components with periods from 19 to 251 kyr to be revealed in this series at a significance level of their amplitudes exceeding 4σ. For this, the combined spectral periodogram (a modification of the spectral analysis method) was used. Some of the revealed quasi-harmonics are related to the characteristic cyclical oscillations of the Earth's orbital parameters. Special focus was payed to the temporal change in the parameters of the revealed quasi-harmonic components over the Pleistocene Epoch, which was studied by constructing the spectral density of the analyzed data in the running window of 201 and 701 kyr.

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

The Interior of the Moon, Core Formation, and the Lunar Hotspot: What Samples Tell Us

NASA Astrophysics Data System (ADS)

Neal, C. R.

1999-01-01

-37, ilmenite extraction will increase this ratio in the residual liquid. Conversely, derivation of a melt from a source rich in ilmenite will produce a melt of lower Zr/ Hf ratio. Hughes and Schmitt defined a mean Zr/Hf for KREEP of 41.0 +/- 0.4, about 39 for Apollo 15 basalts, and 30-32 for Apollo 11, 12, and 17 basalts, with the decreases in Zr/Hf broadly correlating with La/Yb. However, literature data for Apollo 15 KREEP basalts and the KREEP-rich Apollo 14 mare basalts exhibit little variation in Zr/Hf from 36, indicating the KREEP component did not result from a major fractionation of ilmenite and suggesting that the lunar core is probably metallic in overall composition. With volcanic glasses being unrelated to the mare basalts and derived from greater depths, compositional comparisons allow their source regions to be compared. Highly siderophile elements Au and Ir are more abundant in the glasses relative to the basalts. As these elements are generally incompatible in silicate minerals, crystal fractionation experienced by the basalts will tend to increase the Au and It abundances. Therefore, the glasses may be derived from a source enriched in highly siderophile elements such as the platinum-group elements (PGEs) represented by Ir, relative to the source of the basalts. This observation can be accommodated with the basalts being derived from the LMO cumulates and the glasses derived from a source that represents "primitive Moon" that did not melt and, therefore, did not have its budget of PGEs and Au reduced through core formation. This can be tested by analyzing mare basalts and glasses for the PGEs. Although analytically challenging, the first PGE patterns in lunar samples were demonstrated that the source regions for the different Apollo 12 basalts could not be differentiated on the basis of PGE budgets, although the profiles are typical of silicate melts. Analysis of other trace-element data indicate that the high-field-strength elements can be used to

Development and validation of the Core Beliefs Questionnaire in a sample of individuals with social anxiety disorder.

PubMed

Wong, Quincy J J; Gregory, Bree; Gaston, Jonathan E; Rapee, Ronald M; Wilson, Judith K; Abbott, Maree J

2017-01-01

Prominent cognitive models of social anxiety have consistently emphasised the importance of beliefs about the self in the aetiology and maintenance of social anxiety. The present study sought to develop and validate a new measure of core beliefs about the self for SAD, the Core Beliefs Questionnaire (CBQ). Three versions of the CBQ were developed: a Trait version (fundamental absolute statements about the self), a Contingent version (statements about the self related to a specific social-evaluative situation), and an Other version (statements about how others view the self in social-evaluative situations generally). The psychometric features of the scales were examined in clinical (n=269) and non-clinical (n=67) samples. Exploratory factor analysis yielded a one factor model for all three versions of the questionnaire. Total scores differentiated individuals with SAD from individuals without a psychiatric condition, and demonstrated excellent internal consistency. The three CBQ versions had positive associations with social anxiety while controlling for depression, although zero-order correlations indicated the Trait version was more strongly related to depression than social anxiety, the Contingent version was similarly related to depression and social anxiety, and the Other version was more strongly related to social anxiety than depression. Scores on all three versions of the CBQ reduced from pre- to post-treatment and this change predicted treatment outcome. This is the first validation study of the CBQ. This study provides initial support for the reliability and validity of the CBQ. Copyright © 2016 Elsevier B.V. All rights reserved.

The French initiative for scientific cores virtual curating : a user-oriented integrated approach

NASA Astrophysics Data System (ADS)

Pignol, Cécile; Godinho, Elodie; Galabertier, Bruno; Caillo, Arnaud; Bernardet, Karim; Augustin, Laurent; Crouzet, Christian; Billy, Isabelle; Teste, Gregory; Moreno, Eva; Tosello, Vanessa; Crosta, Xavier; Chappellaz, Jérome; Calzas, Michel; Rousseau, Denis-Didier; Arnaud, Fabien

2016-04-01

Managing scientific data is probably one the most challenging issue in modern science. The question is made even more sensitive with the need of preserving and managing high value fragile geological sam-ples: cores. Large international scientific programs, such as IODP or ICDP are leading an intense effort to solve this problem and propose detailed high standard work- and dataflows thorough core handling and curating. However most results derived from rather small-scale research programs in which data and sample management is generally managed only locally - when it is … The national excellence equipment program (Equipex) CLIMCOR aims at developing French facilities for coring and drilling investigations. It concerns indiscriminately ice, marine and continental samples. As part of this initiative, we initiated a reflexion about core curating and associated coring-data management. The aim of the project is to conserve all metadata from fieldwork in an integrated cyber-environment which will evolve toward laboratory-acquired data storage in a near future. In that aim, our demarche was conducted through an close relationship with field operators as well laboratory core curators in order to propose user-oriented solutions. The national core curating initiative currently proposes a single web portal in which all scientifics teams can store their field data. For legacy samples, this will requires the establishment of a dedicated core lists with associated metadata. For forthcoming samples, we propose a mobile application, under Android environment to capture technical and scientific metadata on the field. This application is linked with a unique coring tools library and is adapted to most coring devices (gravity, drilling, percussion, etc...) including multiple sections and holes coring operations. Those field data can be uploaded automatically to the national portal, but also referenced through international standards or persistent identifiers (IGSN, ORCID and INSPIRE

Geochemical Comparison of Four Cores from the Manson Impact Structure

NASA Technical Reports Server (NTRS)

Korotev, Randy L.; Rockow, Kaylynn M.; Jolliff, Bradley L.; Haskin, Larry A.; McCarville, Peter; Crossey, Laura J.

1996-01-01

Concentrations of 33 elements were determined in relatively unaltered, matrix-rich samples of impact breccia at approximately 3-m-depth intervals in the M-1 core from the Manson impact structure, Iowa. In addition, 46 matrix-rich samples from visibly altered regions of the M-7, M-8, and M-10 cores were studied, along with 42 small clasts from all four cores. Major element compositions were determined for a subset of impact breccias from the M-1 core, including matrix-rich impact-melt breccia. Major- and trace-element compositions were also determined for a suite of likely target rocks. In the M-1 core, different breccia units identified from lithologic examination of cores are compositionally distinct. There is a sharp compositional discontinuity at the boundary between the Keweenawan-shale-clast breccia and the underlying unit of impact-melt breccia (IMB) for most elements, suggesting minimal physical mixing between the two units during emplacement. Samples from the 40-m-thick IMB (M-1) are all similar to each other in composition, although there are slight increases in concentration with depth for those elements that have high concentrations in the underlying fragmental-matrix suevite breccia (SB) (e.g., Na, Ca, Fe, Sc), presumably as a result of greater clast proportions at the bottom margin of the unit of impact-melt breccia. The high degree of compositional similarity we observe in the impact-melt breccias supports the interpretation that the matrix of this unit represents impact melt. That our analyses show such compositional similarity results in part from our technique for sampling these breccias: for each sample we analyzed a few small fragments (total mass: approximately 200 mg) selected to be relatively free of large clasts and visible signs of alteration instead of subsamples of powders prepared from a large mass of breccia. The mean composition of the matrix-rich part of impact-melt breccia from the M-1 core can be modeled as a mixture of approximately

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

Fractographic logging for determination of pre-core and core-induced fractures: Nicholas Combs No. 7239 well, Hazard, Kentucky

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

Kulander, B.R.; Dean, S.L.; Barton, C.C.

1977-01-01

Methods results, and conclusions formulated during a prototype fractographic logging study of seventy-five feet of oriented Devonian shale core are summarized. The core analyzed is from the Nicholas Combs No. 7239 well located twelve miles due north of Hazard, Kentucky. The seventy-five foot core length was taken from a cored section lying between 2369.0 feet (subsea) and 2708.0 feet (subsea). Total core length is 339.0 feet. The core was extracted from the upper Devonian Ohio and Olentangy shale formations. Results indicate that there are few tectonic (pre-core) fractures within the studied core section. The region may nevertheless be cut atmore » core sample depth by well-defined vertical or inclined tectonic fractures that the vertically drilled test core didn't intersect. This is likely since surface Plateau systematic fractures in other Plateau areas are vertical to sub-vertical and seldom have a frequency of less than one major fracture per foot. The remarkable directional preference of set three fractures about strikes of N 40/sup 0/ E, N 10/sup 0/ W, N 45/sup 0/ W, suggests some incipient pre-core rock anisotropy or stored directional strain energy. If this situation exists, the anisotropy strike change or stored strain variance from N 40/sup 0/ E to N 45/sup 0/ W downcore remains an unanswered question. Tectonic features, indicating local and/or regional movement plans, are present on and within the tectonichorizontal fracture set one. Slickensides had a preferred orientation within several core levels, and fibrous-nonfibrous calcite serves as fracture fillings.« less

Planetary Sample Caching System Design Options

NASA Technical Reports Server (NTRS)

Collins, Curtis; Younse, Paulo; Backes, Paul

2009-01-01

Potential Mars Sample Return missions would aspire to collect small core and regolith samples using a rover with a sample acquisition tool and sample caching system. Samples would need to be stored in individual sealed tubes in a canister that could be transfered to a Mars ascent vehicle and returned to Earth. A sample handling, encapsulation and containerization system (SHEC) has been developed as part of an integrated system for acquiring and storing core samples for application to future potential MSR and other potential sample return missions. Requirements and design options for the SHEC system were studied and a recommended design concept developed. Two families of solutions were explored: 1)transfer of a raw sample from the tool to the SHEC subsystem and 2)transfer of a tube containing the sample to the SHEC subsystem. The recommended design utilizes sample tool bit change out as the mechanism for transferring tubes to and samples in tubes from the tool. The SHEC subsystem design, called the Bit Changeout Caching(BiCC) design, is intended for operations on a MER class rover.

Tank 241-AP-105, cores 208, 209 and 210, analytical results for the final report

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

Nuzum, J.L.

1997-10-24

This document is the final laboratory report for Tank 241-AP-105. Push mode core segments were removed from Risers 24 and 28 between July 2, 1997, and July 14, 1997. Segments were received and extruded at 222-S Laboratory. Analyses were performed in accordance with Tank 241-AP-105 Push Mode Core Sampling and Analysis Plan (TSAP) (Hu, 1997) and Tank Safety Screening Data Quality Objective (DQO) (Dukelow, et al., 1995). None of the subsamples submitted for total alpha activity (AT), differential scanning calorimetry (DSC) analysis, or total organic carbon (TOC) analysis exceeded the notification limits as stated in TSAP and DQO. The statisticalmore » results of the 95% confidence interval on the mean calculations are provided by the Tank Waste Remediation Systems Technical Basis Group, and are not considered in this report. Appearance and Sample Handling Two cores, each consisting of four segments, were expected from Tank 241-AP-105. Three cores were sampled, and complete cores were not obtained. TSAP states core samples should be transported to the laboratory within three calendar days from the time each segment is removed from the tank. This requirement was not met for all cores. Attachment 1 illustrates subsamples generated in the laboratory for analysis and identifies their sources. This reference also relates tank farm identification numbers to their corresponding 222-S Laboratory sample numbers.« less

A Two-Step Approach to Uncertainty Quantification of Core Simulators

DOE PAGES

Yankov, Artem; Collins, Benjamin; Klein, Markus; ...

2012-01-01

For the multiple sources of error introduced into the standard computational regime for simulating reactor cores, rigorous uncertainty analysis methods are available primarily to quantify the effects of cross section uncertainties. Two methods for propagating cross section uncertainties through core simulators are the XSUSA statistical approach and the “two-step” method. The XSUSA approach, which is based on the SUSA code package, is fundamentally a stochastic sampling method. Alternatively, the two-step method utilizes generalized perturbation theory in the first step and stochastic sampling in the second step. The consistency of these two methods in quantifying uncertainties in the multiplication factor andmore » in the core power distribution was examined in the framework of phase I-3 of the OECD Uncertainty Analysis in Modeling benchmark. With the Three Mile Island Unit 1 core as a base model for analysis, the XSUSA and two-step methods were applied with certain limitations, and the results were compared to those produced by other stochastic sampling-based codes. Based on the uncertainty analysis results, conclusions were drawn as to the method that is currently more viable for computing uncertainties in burnup and transient calculations.« less

Microarray gene expression profiling using core biopsies of renal neoplasia.

PubMed

Rogers, Craig G; Ditlev, Jonathon A; Tan, Min-Han; Sugimura, Jun; Qian, Chao-Nan; Cooper, Jeff; Lane, Brian; Jewett, Michael A; Kahnoski, Richard J; Kort, Eric J; Teh, Bin T

2009-01-01

We investigate the feasibility of using microarray gene expression profiling technology to analyze core biopsies of renal tumors for classification of tumor histology. Core biopsies were obtained ex-vivo from 7 renal tumors-comprised of four histological subtypes-following radical nephrectomy using 18-gauge biopsy needles. RNA was isolated from these samples and, in the case of biopsy samples, amplified by in vitro transcription. Microarray analysis was then used to quantify the mRNA expression patterns in these samples relative to non-diseased renal tissue mRNA. Genes with significant variation across all non-biopsy tumor samples were identified, and the relationship between tumor and biopsy samples in terms of expression levels of these genes was then quantified in terms of Euclidean distance, and visualized by complete linkage clustering. Final pathologic assessment of kidney tumors demonstrated clear cell renal cell carcinoma (4), oncocytoma (1), angiomyolipoma (1) and adrenalcortical carcinoma (1). Five of the seven biopsy samples were most similar in terms of gene expression to the resected tumors from which they were derived in terms of Euclidean distance. All seven biopsies were assigned to the correct histological class by hierarchical clustering. We demonstrate the feasibility of gene expression profiling of core biopsies of renal tumors to classify tumor histology.

Microarray gene expression profiling using core biopsies of renal neoplasia

PubMed Central

Rogers, Craig G.; Ditlev, Jonathon A.; Tan, Min-Han; Sugimura, Jun; Qian, Chao-Nan; Cooper, Jeff; Lane, Brian; Jewett, Michael A.; Kahnoski, Richard J.; Kort, Eric J.; Teh, Bin T.

2009-01-01

We investigate the feasibility of using microarray gene expression profiling technology to analyze core biopsies of renal tumors for classification of tumor histology. Core biopsies were obtained ex-vivo from 7 renal tumors—comprised of four histological subtypes—following radical nephrectomy using 18-gauge biopsy needles. RNA was isolated from these samples and, in the case of biopsy samples, amplified by in vitro transcription. Microarray analysis was then used to quantify the mRNA expression patterns in these samples relative to non-diseased renal tissue mRNA. Genes with significant variation across all non-biopsy tumor samples were identified, and the relationship between tumor and biopsy samples in terms of expression levels of these genes was then quantified in terms of Euclidean distance, and visualized by complete linkage clustering. Final pathologic assessment of kidney tumors demonstrated clear cell renal cell carcinoma (4), oncocytoma (1), angiomyolipoma (1) and adrenalcortical carcinoma (1). Five of the seven biopsy samples were most similar in terms of gene expression to the resected tumors from which they were derived in terms of Euclidean distance. All seven biopsies were assigned to the correct histological class by hierarchical clustering. We demonstrate the feasibility of gene expression profiling of core biopsies of renal tumors to classify tumor histology. PMID:19966938

Performance of ARCHITECT HCV core antigen test with specimens from US plasma donors and injecting drug users.

PubMed

Mixson-Hayden, Tonya; Dawson, George J; Teshale, Eyasu; Le, Thao; Cheng, Kevin; Drobeniuc, Jan; Ward, John; Kamili, Saleem

2015-05-01

Hepatitis C virus (HCV) core antigen is a serological marker of current HCV infection. The aim of this study was mainly to evaluate the performance characteristics of the ARCHITECT HCV core antigen assay with specimens from US plasma donors and injecting drug users. A total of 551 serum and plasma samples with known anti-HCV and HCV RNA status were tested for HCV core antigen using the Abbott ARCHITECT HCV core antigen test. HCV core antigen was detectable in 100% of US plasma donor samples collected during the pre-seroconversion phase of infection (anti-HCV negative/HCV RNA positive). Overall sensitivity of the HCV core antigen assay was 88.9-94.3% in samples collected after seroconversion. The correlation between HCV core antigen and HCV RNA titers was 0.959. HCV core antigen testing may be reliably used to identify current HCV infection. Published by Elsevier B.V.

Sampling design by the core-food approach for the Taiwan total diet study on veterinary drugs.

PubMed

Chen, Chien-Chih; Tsai, Ching-Lun; Chang, Chia-Chin; Ni, Shih-Pei; Chen, Yi-Tzu; Chiang, Chow-Feng

2017-06-01

The core-food (CF) approach, first adopted in the United States in the 1980s, has been widely used by many countries to assess the exposure to dietary hazards at a population level. However, the reliability of exposure estimates (C × CR) depends critically on sampling methods designed for the detected chemical concentrations (C) of each CF to match with the corresponding consumption rate (CR) estimated from the surveyed intake data. In order to reduce the uncertainty of food matching, this study presents a sampling design scheme, namely the subsample method, for the 2016 Taiwan total diet study (TDS) on veterinary drugs. We first combined the four sets of national dietary recall data that covered the entire age strata (1-65+ years), and aggregated them into 307 CFs by their similarity in nutritional values, manufacturing and cooking methods. The 40 CFs pertinent to veterinary drug residues were selected for this study, and 16 subsamples for each CF were designed by weighing their quantities in CR, product brands, manufacturing, processing and cooking methods. The calculated food matching rates of each CF from this study were 84.3-97.3%, which were higher than those obtained from many previous studies using the representative food (RF) method (53.1-57.8%). The subsample method not only considers the variety of food processing and cooking methods, but also it provides better food matching and reduces the uncertainty of exposure assessment.

High Resolution Continuous Flow Analysis System for Polar Ice Cores

NASA Astrophysics Data System (ADS)

Dallmayr, Remi; Azuma, Kumiko; Yamada, Hironobu; Kjær, Helle Astrid; Vallelonga, Paul; Azuma, Nobuhiko; Takata, Morimasa

2014-05-01

In the last decades, Continuous Flow Analysis (CFA) technology for ice core analyses has been developed to reconstruct the past changes of the climate system 1), 2). Compared with traditional analyses of discrete samples, a CFA system offers much faster and higher depth resolution analyses. It also generates a decontaminated sample stream without time-consuming sample processing procedure by using the inner area of an ice-core sample.. The CFA system that we have been developing is currently able to continuously measure stable water isotopes 3) and electrolytic conductivity, as well as to collect discrete samples for the both inner and outer areas with variable depth resolutions. Chemistry analyses4) and methane-gas analysis 5) are planned to be added using the continuous water stream system 5). In order to optimize the resolution of the current system with minimal sample volumes necessary for different analyses, our CFA system typically melts an ice core at 1.6 cm/min. Instead of using a wire position encoder with typical 1mm positioning resolution 6), we decided to use a high-accuracy CCD Laser displacement sensor (LKG-G505, Keyence). At the 1.6 cm/min melt rate, the positioning resolution was increased to 0.27mm. Also, the mixing volume that occurs in our open split debubbler is regulated using its weight. The overflow pumping rate is smoothly PID controlled to maintain the weight as low as possible, while keeping a safety buffer of water to avoid air bubbles downstream. To evaluate the system's depth-resolution, we will present the preliminary data of electrolytic conductivity obtained by melting 12 bags of the North Greenland Eemian Ice Drilling (NEEM) ice core. The samples correspond to different climate intervals (Greenland Stadial 21, 22, Greenland Stadial 5, Greenland Interstadial 5, Greenland Interstadial 7, Greenland Stadial 8). We will present results for the Greenland Stadial -8, whose depths and ages are between 1723.7 and 1724.8 meters, and 35.520 to

CARMA observations of Galactic cold cores: searching for spinning dust emission

NASA Astrophysics Data System (ADS)

Tibbs, C. T.; Paladini, R.; Cleary, K.; Muchovej, S. J. C.; Scaife, A. M. M.; Stevenson, M. A.; Laureijs, R. J.; Ysard, N.; Grainge, K. J. B.; Perrott, Y. C.; Rumsey, C.; Villadsen, J.

2015-11-01

We present the first search for spinning dust emission from a sample of 34 Galactic cold cores, performed using the CARMA interferometer. For each of our cores, we use photometric data from the Herschel Space Observatory to constrain bar{N}H, bar{T}d, bar{n}H, and bar{G}0. By computing the mass of the cores and comparing it to the Bonnor-Ebert mass, we determined that 29 of the 34 cores are gravitationally unstable and undergoing collapse. In fact, we found that six cores are associated with at least one young stellar object, suggestive of their protostellar nature. By investigating the physical conditions within each core, we can shed light on the cm emission revealed (or not) by our CARMA observations. Indeed, we find that only three of our cores have any significant detectable cm emission. Using a spinning dust model, we predict the expected level of spinning dust emission in each core and find that for all 34 cores, the predicted level of emission is larger than the observed cm emission constrained by the CARMA observations. Moreover, even in the cores for which we do detect cm emission, we cannot, at this stage, discriminate between free-free emission from young stellar objects and spinning dust emission. We emphasize that although the CARMA observations described in this analysis place important constraints on the presence of spinning dust in cold, dense environments, the source sample targeted by these observations is not statistically representative of the entire population of Galactic cores.

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.

Probing the inner core's African hemisphere boundary with P'P'

NASA Astrophysics Data System (ADS)

Day, Elizabeth; Ward, James; Bastow, Ian; Irving, Jessica

2017-04-01

Geophysical observations of the inner core today improve our understanding not just of the processes occurring in the core at the present, but also those that occurred in the past. As the inner core freezes it may record clues as to the state of the Earth at the time of growth; the texture in the inner core may also be modified through post-solidification deformation. The seismic structure of the inner core is not simple; the dominant pattern is one of anisotropic and isotropic differences between the Eastern and Western 'hemispheres' of the inner core. Additionally, there is evidence for an innermost inner core, layering of the uppermost inner core, and possibly super-rotation of the inner core relative to the mantle. Most body wave studies of inner core structure use PKP-PKIKP differential travel times to constrain velocity variations within the inner core. However, body wave studies are inherently limited by the geometry of seismic sources and stations, and thus there are some areas of the inner core that are relatively under-sampled, even in today's data-rich world. Here, we examine the differential travel times of the different branches of P'P' (PKIKPPKIKP, or P'P'df, and PKPPKP), comparing the arrival time of inner core turning branch P'P'df with the arrival times of branches that turn in the outer core. By using P'P' we are able to exploit different ray geometries and sample different regions of the inner core to those areas accessible to studies which utilize PKIKP. We use both linear and non-linear stacking methods to make observations of the small amplitude P'P' phases. We identify the three P'P' branches, as well as pre- and post-cursors to the main arrivals, which can cause confusion. To facilitate identifying each P'P' branch we make AxiSEM synthetics, carry out beamforming, and use bootstrapping to access the robustness of our observations, which focus on the inner core's hemisphere boundary beneath Africa. Our measurements match the broad scale

Characterization Data Package for Containerized Sludge Samples Collected from Engineered Container SCS-CON-210

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

Fountain, Matthew S.; Fiskum, Sandra K.; Baldwin, David L.

This data package contains the K Basin sludge characterization results obtained by Pacific Northwest National Laboratory during processing and analysis of four sludge core samples collected from Engineered Container SCS-CON-210 in 2010 as requested by CH2M Hill Plateau Remediation Company. Sample processing requirements, analytes of interest, detection limits, and quality control sample requirements are defined in the KBC-33786, Rev. 2. The core processing scope included reconstitution of a sludge core sample distributed among four to six 4-L polypropylene bottles into a single container. The reconstituted core sample was then mixed and subsampled to support a variety of characterization activities. Additionalmore » core sludge subsamples were combined to prepare a container composite. The container composite was fractionated by wet sieving through a 2,000 micron mesh and a 500-micron mesh sieve. Each sieve fraction was sampled to support a suite of analyses. The core composite analysis scope included density determination, radioisotope analysis, and metals analysis, including the Waste Isolation Pilot Plant Hazardous Waste Facility Permit metals (with the exception of mercury). The container composite analysis included most of the core composite analysis scope plus particle size distribution, particle density, rheology, and crystalline phase identification. A summary of the received samples, core sample reconstitution and subsampling activities, container composite preparation and subsampling activities, physical properties, and analytical results are presented. Supporting data and documentation are provided in the appendices. There were no cases of sample or data loss and all of the available samples and data are reported as required by the Quality Assurance Project Plan/Sampling and Analysis Plan.« less

Occurrence of Radio Minihalos in a Mass-Limited Sample of Galaxy Clusters

NASA Technical Reports Server (NTRS)

Giacintucci, Simona; Markevitch, Maxim; Cassano, Rossella; Venturi, Tiziana; Clarke, Tracy E.; Brunetti, Gianfranco

2017-01-01

We investigate the occurrence of radio minihalos-diffuse radio sources of unknown origin observed in the cores of some galaxy clusters-in a statistical sample of 58 clusters drawn from the Planck Sunyaev-Zeldovich cluster catalog using a mass cut (M(sub 500) greater than 6 x 10(exp 14) solar mass). We supplement our statistical sample with a similarly sized nonstatistical sample mostly consisting of clusters in the ACCEPT X-ray catalog with suitable X-ray and radio data, which includes lower-mass clusters. Where necessary (for nine clusters), we reanalyzed the Very Large Array archival radio data to determine whether a minihalo is present. Our total sample includes all 28 currently known and recently discovered radio minihalos, including six candidates. We classify clusters as cool-core or non-cool-core according to the value of the specific entropy floor in the cluster center, rederived or newly derived from the Chandra X-ray density and temperature profiles where necessary (for 27 clusters). Contrary to the common wisdom that minihalos are rare, we find that almost all cool cores-at least 12 out of 15 (80%)-in our complete sample of massive clusters exhibit minihalos. The supplementary sample shows that the occurrence of minihalos may be lower in lower-mass cool-core clusters. No minihalos are found in non-cool cores or "warm cores." These findings will help test theories of the origin of minihalos and provide information on the physical processes and energetics of the cluster cores.

Alteration of Basalt and Hyaloclastite in the Project Hotspot MHC-2 Core with Some Comparison to Hyaloclastites of the Hawaii Scientific Drilling Program #2 (HSDP) Core

NASA Astrophysics Data System (ADS)

Walton, A. W.; Walker, J. R.

2015-12-01

Project Hotspot's 1821m coring operation at Mountain Home Air Force Base, Idaho (MHC), sought to examine interaction of hotspot magmas with continental crust and evaluate geothermal resources. Subsurface temperature increased at a gradient of 76˚/km. Alteration was uniform and not intense over the upper part of the core and at the bottom, but differed markedly in an anomalous zone (AZ) from 1700 to 1800m. The MHC core contains diatomite, basalt lava and minor hyaloclastite. Olivine (Ol) in lavas is more-or-less altered to iddingsite. Plagioclase (Plag) has altered to smectite along cleavage planes and fractures except in the AZ, where it is intensely altered to corrensite. Clinopyroxene (CPX, pinkish in thin section) is little altered, as are apatite and opaque minerals (probably ilmenite with magnetite or pyrite in different samples). Interstitial material is converted to smectite or, in the AZ, to corrensite. Phyllosilicate lines vesicles, and calcite, zeolite and phyllosilicate fill them. Pore-lining phillipsite is common shallow in the core, with vesicle-filling analcime and heulandite at greater depth. A fibrous zeolite, probably stilbite, is also present. Hyaloclasts are altered to concentrically layered masses of smectite. MHC hyaloclastites do not display the microbial traces and palagonite ("gel-palagonite") alteration common in Hawaii Scientific Drilling Project #2 (HSDP) samples. HSDP samples do contain pore-lining phillipsite, but pore fillings are chabazite. Calcite is absent in HSDP hyaloclastites. Neither Ol nor Plag were altered in HSDP hyaloclastites. HSPD glasses are less silicic and Ti-rich than MHC lavas, containing Ol rather than CPX as a dominant mafic. However the differences in alteration of hyaloclastites probably reflect either the fact that the HSDP core was collected at temperatures equivalent to those at the top of the MHC-2 core or HSDP samples were from beds that were in modified marine pore water, rather than continental waters.

Iron-carbonate interaction at Earth's core-mantle boundary

NASA Astrophysics Data System (ADS)

Dorfman, S. M.; Badro, J.; Nabiei, F.; Prakapenka, V.; Gillet, P.

2015-12-01

Carbon storage and flux in the deep Earth are moderated by oxygen fugacity and interactions with iron-bearing phases. The amount of carbon stored in Earth's mantle versus the core depends on carbon-iron chemistry at the core-mantle boundary. Oxidized carbonates subducted from Earth's surface to the lowermost mantle may encounter reduced Fe0 metal from disproportionation of Fe2+ in lower mantle silicates or mixing with the core. To understand the fate of carbonates in the lowermost mantle, we have performed experiments on sandwiches of single-crystal (Ca0.6Mg0.4)CO3 dolomite and Fe foil in the laser-heated diamond anvil cell at lower mantle conditions of 49-110 GPa and 1800-2500 K. Syntheses were conducted with in situ synchrotron X-ray diffraction to identify phase assemblages. After quench to ambient conditions, samples were sectioned with a focused Ga+ ion beam for composition analysis with transmission electron microscopy. At the centers of the heated spots, iron melted and reacted completely with the carbonate to form magnesiowüstite, iron carbide, diamond, magnesium-rich carbonate and calcium carbonate. In samples heated at 49 and 64 GPa, the two carbonates exhibit a eutectoid texture. In the sample heated at 110 GPa, the carbonates form rounded ~150-nm-diameter grains with a higher modal proportion of interspersed diamonds. The presence of reduced iron in the deep lower mantle and core-mantle boundary region will promote the formation of diamonds in carbonate-bearing subducted slabs. The complete reaction of metallic iron to oxides and carbides in the presence of mantle carbonate supports the formation of these phases at the Earth's core-mantle boundary and in ultra-low velocity zones.

Neighborhood sampling: how many streets must an auditor walk?

PubMed

McMillan, Tracy E; Cubbin, Catherine; Parmenter, Barbara; Medina, Ashley V; Lee, Rebecca E

2010-03-12

This study tested the representativeness of four street segment sampling protocols using the Pedestrian Environment Data Scan (PEDS) in eleven neighborhoods surrounding public housing developments in Houston, TX. The following four street segment sampling protocols were used (1) all segments, both residential and arterial, contained within the 400 meter radius buffer from the center point of the housing development (the core) were compared with all segments contained between the 400 meter radius buffer and the 800 meter radius buffer (the ring); all residential segments in the core were compared with (2) 75% (3) 50% and (4) 25% samples of randomly selected residential street segments in the core. Analyses were conducted on five key variables: sidewalk presence; ratings of attractiveness and safety for walking; connectivity; and number of traffic lanes. Some differences were found when comparing all street segments, both residential and arterial, in the core to the ring. Findings suggested that sampling 25% of residential street segments within the 400 m radius of a residence sufficiently represents the pedestrian built environment. Conclusions support more cost effective environmental data collection for physical activity research.

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.

University of TX Bureau of Economic Geology's Core Research Centers: The Time is Right for Registering Physical Samples and Assigning IGSN's - Workflows, Stumbling Blocks, and Successes.

NASA Astrophysics Data System (ADS)

Averett, A.; DeJarnett, B. B.

2016-12-01

The University Of Texas Bureau Of Economic Geology (BEG) serves as the geological survey for Texas and operates three geological sample repositories that house well over 2 million boxes of geological samples (cores and cuttings) and an abundant amount of geoscience data (geophysical logs, thin sections, geochemical analyses, etc.). Material is accessible and searchable online, and it is publically available to the geological community for research and education. Patrons access information about our collection by using our online core and log database (SQL format). BEG is currently undertaking a large project to: 1) improve the internal accuracy of metadata associated with the collection; 2) enhance the capabilities of the database for both BEG curators and researchers as well as our external patrons; and 3) ensure easy and efficient navigation for patrons through our online portal. As BEG undertakes this project, BEG is in the early stages of planning to export the metadata for its collection into SESAR (System for Earth Sample Registration) and have IGSN's (International GeoSample Numbers) assigned to its samples. Education regarding the value of IGSN's and an external registry (SESAR) has been crucial to receiving management support for the project because the concept and potential benefits of registering samples in a registry outside of the institution were not well-known prior to this project. Potential benefits such as increases in discoverability, repository recognition in publications, and interoperability were presented. The project was well-received by management, and BEG fully supports the effort to register our physical samples with SESAR. Since BEG is only in the initial phase of this project, any stumbling blocks, workflow issues, successes/failures, etc. can only be predicted at this point, but by mid-December, BEG expects to have several concrete issues to present in the session. Currently, our most pressing issue involves establishing the most

Electrochemistry and the Earth's Core-Mantle Boundary

NASA Astrophysics Data System (ADS)

Kavner, A.; Walker, D.

2001-12-01

The Earth's core-mantle boundary consists of a highly heterogeneous metal-oxide interface subjected to high temperatures, pressures, and additionally, to the presence of a temporally- and spatially-varying electrical field generated by the outer core dynamo. An understanding of the core-mantle boundary should include the nature of its electrical behavior, its electrically induced chemical partitioning, and any resultant core-mantle dynamic coupling. To this end, we have developed a method to measure the electrical behavior of metal-silicate interfaces at high pressures (15-25 kbar) and temperatures (1300-1400° C) in a piston-cylinder apparatus. Platinum electrical leads are placed at each end of the sample, which consists of a layer of iron and/or iron alloy below a layer of silicate. The sample is enclosed in a sintered MgO chamber which is then surrounded by a metal Faraday cage, allowing the sample to be electrically insulated from the AC field of the graphite heater. The platinum electric leads are threaded through the thermocouple tube and connected with an HP4284A LCR meter to measure AC impedance, or to a DC power supply to apply a field such that either the silicate or the metal end is the anode (+). AC impedance measurements performed in-situ on samples consisting of Fe, Fe-Ni-S, and a basalt-olivine mixture in series show that conductivity is strongly dependent on the electrical polarization of the silicate relative to the sulfide. When the silicate is positively charged (silicate is the anode) and when there is no applied charge, the probe-to-probe resistance displays semiconductor behavior, with conductivity ( ~10-2 S/cm) strongly thermally activated. However, when the electrical polarity is reversed, and the sulfide is the anode, the electrical conductivity between the two probes increases dramatically (to ~1 S/cm) over timescales of minutes. If the polarity is removed or reversed, the conductivity returns to its original values over similar

Preparations to ship the TMI-2 damaged reactor core

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

Schmitt, R.C.; Quinn, G.J.

1985-11-01

The March 1979 accident at Three Mile Island Unit 2 (TMI-2) resulted in a severely damaged core. Entries into that core using various tools and inspection devices have shown a significant void, large amounts of rubble, partially intact fuel assemblies, and some resolidified molten materials. The removal and disposition of that core has been of considerable public, regulatory, and governmental interest for some time. In a contractual agreement between General Public Utility Nuclear (GPUN) and the US Department of Energy (DOE), DOE has agreed to accept the TMI-2 core for interim storage at the Idaho National Engineering Laboratory (INEL), conductmore » research on fuel and materials of the core, and eventually dispose of the core either by processing or internment at the national repository. GPUN has removed various samples of material from the core and was scheduled to begin extensive defueling operations in September 1985. EG and G Idaho, Inc. (EG and G), acting on behalf of DOE, is responsible for transporting, receiving, examining, and storing the TMI-2 core. This paper addresses the preparations to ship the core to INEL, which is scheduled to commence in March 1986.« less

Sample Acquisition and Caching architecture for the Mars Sample Return mission

NASA Astrophysics Data System (ADS)

Zacny, K.; Chu, P.; Cohen, J.; Paulsen, G.; Craft, J.; Szwarc, T.

This paper presents a Mars Sample Return (MSR) Sample Acquisition and Caching (SAC) study developed for the three rover platforms: MER, MER+, and MSL. The study took into account 26 SAC requirements provided by the NASA Mars Exploration Program Office. For this SAC architecture, the reduction of mission risk was chosen by us as having greater priority than mass or volume. For this reason, we selected a “ One Bit per Core” approach. The enabling technology for this architecture is Honeybee Robotics' “ eccentric tubes” core breakoff approach. The breakoff approach allows the drill bits to be relatively small in diameter and in turn lightweight. Hence, the bits could be returned to Earth with the cores inside them with only a modest increase to the total returned mass, but a significant decrease in complexity. Having dedicated bits allows a reduction in the number of core transfer steps and actuators. It also alleviates the bit life problem, eliminates cross contamination, and aids in hermetic sealing. An added advantage is faster drilling time, lower power, lower energy, and lower Weight on Bit (which reduces Arm preload requirements). Drill bits are based on the BigTooth bit concept, which allows re-use of the same bit multiple times, if necessary. The proposed SAC consists of a 1) Rotary-Percussive Core Drill, 2) Bit Storage Carousel, 3) Cache, 4) Robotic Arm, and 5) Rock Abrasion and Brushing Bit (RABBit), which is deployed using the Drill. The system also includes PreView bits (for viewing of cores prior to caching) and Powder bits for acquisition of regolith or cuttings. The SAC total system mass is less than 22 kg for MER and MER+ size rovers and less than 32 kg for the MSL-size rover.

Assessing the fate of radioactive nickel in cultivated soil cores.

PubMed

Denys, Sébastien; Echevarria, Guillaume; Florentin, Louis; Leclerc, Elisabeth; Morel, Jean-Louis

2009-10-01

Parameters regarding fate of (63)Ni in the soil-plant system (soil: solution distribution coefficient, K(d) and soil plant concentration ratio, CR) are mostly determined in controlled pot experiments or from simple models involving a limited set of soil parameters. However, as migration of pollutants in soil is strongly linked to the water migration, variation of soil structure in the field and seasonal variation of evapotranspiration will affect these two parameters. The aim of this work was to explore to what extent the downward transfer of (63)Ni and its uptake by plants from surface-contaminated undisturbed soil cores under cultivation can be explained by isotopic dilution of this radionuclide in the pool of stable Ni of soils. Undisturbed soil cores (50 cm x 50 cm) were sampled from a brown rendzina (Rendzic Leptosol), a colluvial brown soil (Fluvic Cambisol) and an acidic brown soil (Dystric Cambisol) using PVC lysimeter tubes (three lysimeters sampled per soil type). Each core was equipped with a leachate collector. Cores were placed in a greenhouse and maize (DEA, Pioneer) was sown. After 44 days, an irrigation was simulated at the core surfaces to supply 10 000 Bq (63)NiCl(2). Maize was harvested 135 days after (63)Ni input and radioactivity determined in both vegetal and water samples. Effective uptake of (63)Ni by maize was calculated for leaves and kernels. Water drainage and leaching of (63)Ni were monitored over the course of the experiment. Values of K(d) in surface soil samples were calculated from measured parameters of isotopic exchange kinetics. Results confirmed that (63)Ni was strongly retained at the soil surface. Prediction of the (63)Ni downward transfer could not be reliably assessed using the K(d) values, since the soil structure, which controls local water fluxes, also affected both water and Ni transport. In terms of (63)Ni plant uptake, the effective uptake in undisturbed soil cores is controlled by isotope dilution as previously shown

Application of fractography to core and outcrop fracture investigations

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

Kulander, B.R.; Barton, C.C.; Dean, S.L.

1979-03-01

Purpose of this paper is to introduce geologists to the principles of fractography, especially those principles that govern the formation of fracture surface structures commonly observed in rocks. A knowledge of the inception mechanics governing the formation of a fracture's tendential and transient structures should provide geologists with a method to distinguish natural from coring-induced and handling-induced fractures in oriented core samples, and show how coring-induced fractures may be assisted in their formation by stresses that can be attributed to the drilling process. 118 figures.

Inner Core Anisotropy in Attenuation

NASA Astrophysics Data System (ADS)

Yu, W.; Wen, L.

2004-12-01

It is now well established that the compressional velocity in the Earth's inner core varies in both direction and geographic location. The compressional waves travel faster along the polar directions than along the equatorial directions. Such polar-equatorial difference is interpreted as a result of inner core anisotropy in velocity (with a magnitude of about 3%) and such anisotropy appears to be stronger in the ``western hemisphere" (180oW -40oE) than in the ``eastern hemisphere" (40oE-180oE). Along the equatorial paths, the compressional velocity also exhibits a hemispheric pattern with the eastern hemisphere being about 1% higher than the western hemisphere. Possible explanations for the causes of the velocity in anisotropy and the hemispheric difference in velocity along the equatorial paths include different geometric inclusions of melt or different alignments of iron crystals which are known to be anisotropic in velocities. Here, we report an observation of ubiquitous correlation between small (large) amplitude and fast (slow) travel time of the PKIKP waves sampling the top 300 km of the inner core. We study this correlation by jointly analyzing the differential travel times and amplitude ratios of the PKiKP-PKIKP and the PKPbc-PKIKP phases recorded by the Global Seismographic Network (1990-2001), various regional seismic networks (BANJO, BLSP, FREESIA, GEOFON, GEOSCOPE, Kazakhstan, Kyrgyz, MEDNET, and OHP), and several PASSCAL Networks deployed in Alaska and Antarctica (XE: 1999-2001, XF: 1995-1996, and YI: 1998-1999). Our dataset consists of 310 PKiKP-PKIKP and 240 PKPbc-PKIKP phases, selected from a total of more than 16,000 observations. PKIKP waves exhibit relatively smaller amplitudes for those sampling the eastern hemisphere along the equatorial paths and even smaller amplitudes for those sampling the polar paths in the western hemisphere. One simple explanation for the velocity-attenuation relation is that the inner core is anisotropic in attenuation

Performance of the NASA Digitizing Core-Loss Instrumentation

NASA Technical Reports Server (NTRS)

Schwarze, Gene E. (Technical Monitor); Niedra, Janis M.

2003-01-01

The standard method of magnetic core loss measurement was implemented on a high frequency digitizing oscilloscope in order to explore the limits to accuracy when characterizing high Q cores at frequencies up to 1 MHz. This method computes core loss from the cycle mean of the product of the exciting current in a primary winding and induced voltage in a separate flux sensing winding. It is pointed out that just 20 percent accuracy for a Q of 100 core material requires a phase angle accuracy of 0.1 between the voltage and current measurements. Experiment shows that at 1 MHz, even high quality, high frequency current sensing transformers can introduce phase errors of a degree or more. Due to the fact that the Q of some quasilinear core materials can exceed 300 at frequencies below 100 kHz, phase angle errors can be a problem even at 50 kHz. Hence great care is necessary with current sensing and ground loops when measuring high Q cores. Best high frequency current sensing accuracy was obtained from a fabricated 0.1-ohm coaxial resistor, differentially sensed. Sample high frequency core loss data taken with the setup for a permeability-14 MPP core is presented.

Some physical properties of Apollo 12 lunar samples

NASA Technical Reports Server (NTRS)

Gold, T.; Oleary, B. T.; Campbell, M.

1971-01-01

The size distribution of the lunar fines is measured, and small but significant differences are found between the Apollo 11 and 12 samples as well as among the Apollo 12 core samples. The observed differences in grain size distribtuion in the core samples are related to surface transportation processes, and the importance of a sedimentation process versus meteoritic impact gardening of the mare grounds is discussed. The optical and the radio frequency electrical properties are measured and are also found to differ only slightly from Apollo 11 results.

The lunar core and the origin of the moon

NASA Astrophysics Data System (ADS)

Newsom, H. E.

1984-05-01

The results of recent analyses of concentrations of refractory siderophile elements molybdenum and rhenium in lunar rock samples suggest that most siderophile elements in lunar crustal rocks and mare basalts are significantly less concentrated than in the earth's mantle and much less than in chondrite meteorites. The depletion of siderophile elements in the samples implies the existence of a metal core, and the amount of metal in the core is directly related to the conditions under which segregation occurs. The consequences of the data are discussed in terms of three theoretical models of lunar evolution: a terrestrial origin model; a terrestrial origin model which takes metal segregation into account; and an independent origin model. It is shown that less metal is needed for a terrestrial origin because the earth's mantle was already partially depleted in siderophile elements due to the formation of the earth core.

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.

Sampling requirements for forage quality characterization of rectangular hay bales

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

Sheaffer, C.C.; Martin, N.P.; Jewett, J.G.

2000-02-01

Commercial lots of alfalfa (Medicago sativa L.) hay are often bought and sold on the basis of forage quality. Proper sampling is essential to obtain accurate forage quality results for pricing of alfalfa hay, but information about sampling is limited to small, 20- to 40-kg rectangular bales. Their objectives were to determine the within-bale variation in 400-kg rectangular bales and to determine the number and distribution of core samples required to represent the crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and dry matter (DM) concentration in commercial lots of alfalfa hay. Four bales were selected frommore » each of three hay lots and core sampled nine times per side for a total of 54 cores per bale. There was no consistent pattern of forage quality variation within bales. Averaged across lots, any portion of a bale was highly correlated with bale grand means for CP, ADF, NDF, and DM. Three lots of hay were probed six times per bale, one core per bale side from 55, 14, and 14 bales per lot. For determination of CP, ADF, NDF, and DM concentration, total core numbers required to achieve an acceptable standard error (SE) were minimized by sampling once per bale. Bootstrap analysis of data from the most variable hay lot suggested that forage quality of any lot of 400-kg alfalfa hay bales should be adequately represented by 12 bales sampled once per bale.« less

Hot flashes, core body temperature, and metabolic parameters in breast cancer survivors.

PubMed

Carpenter, Janet S; Gilchrist, Janet M; Chen, Kong; Gautam, Shiva; Freedman, Robert R

2004-01-01

To examine core body temperature, energy expenditure, and respiratory quotient among breast cancer survivors experiencing hot flashes and compare these data to published studies from healthy women. In an observational study, nine breast cancer survivors with daily hot flashes who met specified criteria spent 24 hours in a temperature- and humidity-controlled whole-room indirect calorimeter (ie, metabolic room). Demographic and disease/treatment information were obtained and the following were measured: hot flashes via sternal skin conductance monitoring (sampled every second); core body temperature via an ingested radiotelemetry pill (sampled every 10 seconds); and energy expenditure and respiratory quotient via a whole-room indirect calorimeter (calculated every minute). Circadian analysis of core temperature indicated wide variability with disrupted circadian rhythm noted in all women. Core temperature began to rise 20 minutes pre-flash to 7 minutes pre-flash (0.09 degrees C increase). Increases in energy expenditure and respiratory quotient increased with each hot flash. Findings are comparable to published data from healthy women and warrant replication in larger, more diverse samples of women treated for breast cancer.

Comparing Written Competency in Core French and French Immersion Graduates

ERIC Educational Resources Information Center

Lappin-Fortin, Kerry

2014-01-01

Few studies have compared the written competency of French immersion students and their core French peers, and research on these learners at a postsecondary level is even scarcer. My corpus consists of writing samples from 255 students from both backgrounds beginning a university course in French language. The writing proficiency of core French…

Occurrence of Radio Minihalos in a Mass-limited Sample of Galaxy Clusters

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

Giacintucci, Simona; Clarke, Tracy E.; Markevitch, Maxim

2017-06-01

We investigate the occurrence of radio minihalos—diffuse radio sources of unknown origin observed in the cores of some galaxy clusters—in a statistical sample of 58 clusters drawn from the Planck Sunyaev–Zel’dovich cluster catalog using a mass cut ( M {sub 500} > 6 × 10{sup 14} M {sub ⊙}). We supplement our statistical sample with a similarly sized nonstatistical sample mostly consisting of clusters in the ACCEPT X-ray catalog with suitable X-ray and radio data, which includes lower-mass clusters. Where necessary (for nine clusters), we reanalyzed the Very Large Array archival radio data to determine whether a minihalo is present.more » Our total sample includes all 28 currently known and recently discovered radio minihalos, including six candidates. We classify clusters as cool-core or non-cool-core according to the value of the specific entropy floor in the cluster center, rederived or newly derived from the Chandra X-ray density and temperature profiles where necessary (for 27 clusters). Contrary to the common wisdom that minihalos are rare, we find that almost all cool cores—at least 12 out of 15 (80%)—in our complete sample of massive clusters exhibit minihalos. The supplementary sample shows that the occurrence of minihalos may be lower in lower-mass cool-core clusters. No minihalos are found in non-cool cores or “warm cores.” These findings will help test theories of the origin of minihalos and provide information on the physical processes and energetics of the cluster cores.« less

The Interior Angular Momentum of Core Hydrogen Burning Stars from Gravity-mode Oscillations

NASA Astrophysics Data System (ADS)

Aerts, C.; Van Reeth, T.; Tkachenko, A.

2017-09-01

A major uncertainty in the theory of stellar evolution is the angular momentum distribution inside stars and its change during stellar life. We compose a sample of 67 stars in the core hydrogen burning phase with a {log} g value from high-resolution spectroscopy, as well as an asteroseismic estimate of the near-core rotation rate derived from gravity-mode oscillations detected in space photometry. This assembly includes 8 B-type stars and 59 AF-type stars, covering a mass range from 1.4 to 5 M ⊙, I.e., it concerns intermediate-mass stars born with a well-developed convective core. The sample covers projected surface rotation velocities v\\sin I\\in [9,242] km s-1 and core rotation rates up to 26 μHz, which corresponds to 50% of the critical rotation frequency. We find deviations from rigid rotation to be moderate in the single stars of this sample. We place the near-core rotation rates in an evolutionary context and find that the core rotation must drop drastically before or during the short phase between the end of the core hydrogen burning and the onset of core helium burning. We compute the spin parameter, which is the ratio of twice the rotation rate to the mode frequency (also known as the inverse Rossby number), for 1682 gravity modes and find the majority (95%) to occur in the sub-inertial regime. The 10 stars with Rossby modes have spin parameters between 14 and 30, while the gravito-inertial modes cover the range from 1 to 15.

Proceedings of the wellbore sampling workshop

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

Traeger, R.K.; Harding, B.W.

Representatives from academia, industry and research laboratories participated in an intensive two-day review to identify major technological limitations in obtaining solid and fluid samples from wellbores. Top priorities identified for further development include: coring of hard and unconsolidated materials; flow through fluid samplers with borehole measurements T, P and pH; and nonintrusive interrogation of pressure cores.

Revised South China Sea spreading history based on macrostructure analysis of IODP Expedition 349 core samples and geophysical data

NASA Astrophysics Data System (ADS)

Sun, Z.; Ding, W.; Zhao, X.; Qiu, N.; Lin, J.; Li, C.

2017-12-01

In Internaltional Ocean Discovery Program (IODP) Expedition 349, four sites were drilled and cored successfully in the South China Sea (SCS). Three of them are close to the central spreading ridge (Sites U1431, U1433 and U1434), and one (Site U1435) is located on an outer rise,,providingsignificant information on the spreading history of the SCS.In order to constrain the spreading historymore accurately with the core results, we analyzed the identifiable macrostructures (over 300 fractures, veins and slickensides)from all the consolidated samples of these four drill sites. Then we made a retrograde reconstruction of the SCS spreading history with the constraints of the estimated fractures and veins, post-spreading volcanism,seismic interpretation, as well as free-air gravity and magnetic anomaly and topography analysis. Our study indicates that the spreading of the SCS experienced at least one ridge jump event and two events of ridge orientation and spreading direction adjustment, which mademagnetic anomaly orientation, ridge positionand facture zone directionskeep changing in the South China Sea. During the last spreading stage, the spreading direction was north-southward but lasted for a very short time period. The oceanic crust is wider in the eastern SCS and tapers out toward west.Due to the subductionof SCS beneath the Philippine Sea plate, the seafloor began to develop new fractures:the NWW-to EW-trending R' shear faults and the NE-trending P faultsbecame dominant faults and controlled the eruption of post-drift volcanism.

Studies of pre-Selma Cretaceous core samples from the outcrop area in western Alabama

USGS Publications Warehouse

Monroe, Watson Hiner; Bergenback, Richard E.; Sohl, Norman F.; Applin, Esther R.; Leopold, Estella B.; Pakiser, Helen M.; Conant, Louis C.

1964-01-01

Quarter-cuts of the cores belonging to the U.S. National Museum have been deposited on indefinite loan with the Alabama Geological Survey at University, Ala., and with the Shell Oil Co. at Jackson, Miss. They are available there for inspection and study.

Contamination Control of Freeze Shoe Coring System for Collection of Aquifer Sands

NASA Astrophysics Data System (ADS)

Homola, K.; van Geen, A.; Spivack, A. J.; Grzybowski, B.; Schlottenmier, D.

2017-12-01

We have developed and tested an original device, the freeze-shoe coring system, designed to recover undisturbed samples of water contained in sand-dominated aquifers. Aquifer sands are notoriously difficult to collect together with porewater from coincident depths, as high hydraulic permeability leads to water drainage and mixing during retrieval. Two existing corer designs were reconfigured to incorporate the freeze-shoe system; a Hydraulic Piston (HPC) and a Rotary (RC) Corer. Once deployed, liquid CO­2 contained in an interior tank is channeled to coils at the core head where it changes phase, rapidly cooling the deepest portion of the core. The resulting frozen core material impedes water loss during recovery. We conducted contamination tests to examine the integrity of cores retrieved during a March 2017 yard test deployment. Perfluorocarbon tracer (PFC) was added to the drill fluid and recovered cores were subsampled to capture the distribution of PFC throughout the core length and interior. Samples were collected from two HPC and one RC core and analyzed for PFC concentrations. The lowest porewater contamination, around 0.01% invasive fluid, occurs in the center of both HPC cores. The greatest contamination (up to 10%) occurs at the disturbed edges where core material contacts drill fluid. There was lower contamination in the core interior than top, bottom, and edges, as well as significantly lower contamination in HPC cores that those recovered with the RC. These results confirm that the freeze-shoe system, proposed for field test deployments in West Bengal, India, can successfully collect intact porewater and sediment material with minimal if any contamination from drill fluid.

A new method for geochemical characterization of atmospheric mineral dust from polar ice cores: preliminary results from Talos Dome ice core (East Antarctica, Pacific-Ross Sea sector)

NASA Astrophysics Data System (ADS)

Baccolo, Giovanni; Delmonte, Barbara; Clemenza, Massimiliano; Previtali, Ezio; Maggi, Valter

2015-04-01

Assessing the elemental composition of atmospheric dust entrapped in polar ice cores is important for the identification of the potential dust sources and thus for the reconstruction of past atmospheric circulation, at local, regional and global scale. Accurate determination of major and trace elements in the insoluble fraction of dust extracted from ice cores is also useful to better understand some geochemical and biogeochemical mechanisms which are linked with the climate system. The extremely reduced concentration of dust in polar ice (typical Antarctic concentrations during interglacials are in the range of 10 ppb), the limited availability of such samples and the high risk of contamination make these analyses a challenge. A new method based on low background Instrumental Neutron Activation Analysis (INAA) was specifically developed for this kind of samples. The method allows the determination of the concentration of up to 35 elements in extremely reduced dust samples (20-30 μg). These elements span from major to trace and ultra-trace elements. Preliminary results from TALDICE (TALos Dome Ice CorE, East Antarctica, Pacific-Ross Sea Sector) ice core are presented along with results from potential source areas in Victoria Land. A set of 5 samples from Talos Dome, corresponding to the last termination, MIS3, MIS4 and MIS6 were prepared and analyzed by INAA.

15N fractionation in infrared-dark cloud cores

NASA Astrophysics Data System (ADS)

Zeng, S.; Jiménez-Serra, I.; Cosentino, G.; Viti, S.; Barnes, A. T.; Henshaw, J. D.; Caselli, P.; Fontani, F.; Hily-Blant, P.

2017-07-01

Context. Nitrogen is one of the most abundant elements in the Universe and its 14N/15N isotopic ratio has the potential to provide information about the initial environment in which our Sun formed. Recent findings suggest that the solar system may have formed in a massive cluster since the presence of short-lived radioisotopes in meteorites can only be explained by the influence of a supernova. Aims: We seek to determine the 14N/15N ratio towards a sample of cold and dense cores at the initial stages in their evolution. Methods: We observed the J = 1 → 0 transitions of HCN, H13CN, HC15N, HN13C, and H15NC towards a sample of 22 cores in four infrared-dark clouds (IRDCs) which are believed to be the precursors of high-mass stars and star clusters. Assuming LTE and a temperature of 15 K, the column densities of HCN, H13CN, HC15N, HN13C, and H15NC are calculated and their 14N/15N ratio is determined for each core. Results: The 14N/15N ratios measured in our sample of IRDC cores range between 70 and ≥763 in HCN and between 161 and 541 in HNC. These ratios are consistent with the terrestrial atmosphere (TA) and protosolar nebula (PSN) values, and with the ratios measured in low-mass prestellar cores. However, the 14N/15N ratios measured in cores C1, C3, F1, F2, and G2 do not agree with the results from similar studies towards the same cores using nitrogen bearing molecules with nitrile functional group (-CN) and nitrogen hydrides (-NH) although the ratio spread covers a similar range. Conclusions: Relatively low 14N/15N ratios amongst the four-IRDCs were measured in IRDC G which are comparable to those measured in small cosmomaterials and protoplanetary disks. The low average gas density of this cloud suggests that the gas density, rather than the gas temperature, may be the dominant parameter influencing the initial nitrogen isotopic composition in young PSN. The reduced spectra (FITS files) are only available at the CDS via anonymous ftp to http

Effects of core self-evaluations on the job burnout of nurses: the mediator of organizational commitment.

PubMed

Zhou, Yangen; Lu, Jiamei; Liu, Xianmin; Zhang, Pengcheng; Chen, Wuying

2014-01-01

To explore the impact of Core self-evaluations on job burnout of nurses, and especially to test and verify the mediator role of organizational commitment between the two variables. Random cluster sampling was used to pick up participants sample, which consisted of 445 nurses of a hospital in Shanghai. Core self-evaluations questionnaire, job burnout scale and organizational commitment scale were administrated to the study participants. There are significant relationships between Core self-evaluations and dimensions of job burnout and organizational commitment. There is a significant mediation effect of organizational commitment between Core self-evaluations and job burnout. To enhance nurses' Core self-evaluations can reduce the incidence of job burnout.

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.

Results of NanTroSEIZE Expeditions Stages 1 & 2: Deep-sea Coring Operations on-board the Deep-sea Drilling Vessel Chikyu and Development of Coring Equipment for Stage 3

NASA Astrophysics Data System (ADS)

Shinmoto, Y.; Wada, K.; Miyazaki, E.; Sanada, Y.; Sawada, I.; Yamao, M.

2010-12-01

The Nankai-Trough Seismogenic Zone Experiment (NanTroSEIZE) has carried out several drilling expeditions in the Kumano Basin off the Kii-Peninsula of Japan with the deep-sea scientific drilling vessel Chikyu. Core sampling runs were carried out during the expeditions using an advanced multiple wireline coring system which can continuously core into sections of undersea formations. The core recovery rate with the Rotary Core Barrel (RCB) system was rather low as compared with other methods such as the Hydraulic Piston Coring System (HPCS) and Extended Shoe Coring System (ESCS). Drilling conditions such as hole collapse and sea conditions such as high ship-heave motions need to be analyzed along with differences in lithology, formation hardness, water depth and coring depth in order to develop coring tools, such as the core barrel or core bit, that will yield the highest core recovery and quality. The core bit is especially important in good recovery of high quality cores, however, the PDC cutters were severely damaged during the NanTroSEIZE Stages 1 & 2 expeditions due to severe drilling conditions. In the Stage 1 (riserless coring) the average core recovery was rather low at 38 % with the RCB and many difficulties such as borehole collapse, stick-slip and stuck pipe occurred, causing the damage of several of the PDC cutters. In Stage 2, a new design for the core bit was deployed and core recovery was improved at 67 % for the riserless system and 85 % with the riser. However, due to harsh drilling conditions, the PDC core bit and all of the PDC cutters were completely worn down. Another original core bit was also deployed, however, core recovery performance was low even for plate boundary core samples. This study aims to identify the influence of the RCB system specifically on the recovery rates at each of the holes drilled in the NanTroSEIZE coring expeditions. The drilling parameters such as weight-on-bit, torque, rotary speed and flow rate, etc., were analyzed

Diversity captured in the USDA-ARS National Plant Germplasm System apple core collection

USDA-ARS?s Scientific Manuscript database

Core collections have been used widely in genetic resources to provide a representative and compact sample to use in breeding evaluation. In the 1990s a core set was developed by the USDA-ARS Plant Genetic Resources Unit (PGRU) in Geneva, NY. Using data available at the time, a core set was develo...

Neighborhood sampling: how many streets must an auditor walk?

PubMed Central

2010-01-01

This study tested the representativeness of four street segment sampling protocols using the Pedestrian Environment Data Scan (PEDS) in eleven neighborhoods surrounding public housing developments in Houston, TX. The following four street segment sampling protocols were used (1) all segments, both residential and arterial, contained within the 400 meter radius buffer from the center point of the housing development (the core) were compared with all segments contained between the 400 meter radius buffer and the 800 meter radius buffer (the ring); all residential segments in the core were compared with (2) 75% (3) 50% and (4) 25% samples of randomly selected residential street segments in the core. Analyses were conducted on five key variables: sidewalk presence; ratings of attractiveness and safety for walking; connectivity; and number of traffic lanes. Some differences were found when comparing all street segments, both residential and arterial, in the core to the ring. Findings suggested that sampling 25% of residential street segments within the 400 m radius of a residence sufficiently represents the pedestrian built environment. Conclusions support more cost effective environmental data collection for physical activity research. PMID:20226052

Thermo-responsive polymer tethered metal-organic framework core-shell magnetic microspheres for magnetic solid-phase extraction of alkylphenols from environmental water samples.

PubMed

Jia, Yuqian; Su, Hao; Wong, Y-L Elaine; Chen, Xiangfeng; Dominic Chan, T-W

2016-07-22

In this work, the thermo-responsive polymer PNIPAM tethered to Fe3O4@SiO2@MOF core-shell magnetic microspheres was first synthesized by a surface-selective post-synthetic strategy and underwent highly efficient magnetic solid-phase extraction (MSPE) of alkylphenols from aqueous samples. Alkylphenols, including 4-tert-octylphenol (OP) and 4-n-nonylphenol (NP), were selected as target compounds. The sample quantification was carried out using LC-MS/MS in multiple reaction monitor (MRM) mode. Under optimal working conditions, the developed method showed good linearity in the range of 5-1000ngL(-1), a low limit of detection (1.5ngL(-1)), and good repeatability (relative standard deviation, <8%, n=5) for NP and OP. Owning to the hydrophilic/hydrophobic switchable properties of the nanocomposite, high recoveries (78.7-104.3%) of alkylphenols were obtained under different extraction conditions. The levels of OP and NP in environmental samples collected from local river, lake and pond waters were analyzed using the developed method. It was believed that the synthesized material with the thermo-responsive coating, large surface areas and magnetic properties should have great potential in the extraction and removal of alkylphenols from environmental samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Core food of the French food supply: second Total Diet Study.

PubMed

Sirot, V; Volatier, J L; Calamassi-Tran, G; Dubuisson, C; Menard, C; Dufour, A; Leblanc, J C

2009-05-01

As first described in the 1980s, the core food intake model allows a precise assessment of dietary nutrient intake and dietary exposure to contaminants insofar as it reflects the eating habits of a target population and covers the most important foods in terms of consumption, selected nutrient and contaminant contribution. This model has been used to set up the sampling strategy of the second French Total Diet Study (TDS) with the aim of obtaining a realistic panorama of nutrient intakes and contaminant exposure for the whole population, useful for quantitative risk assessment. Data on consumption trends and eating habits from the second French individual food consumption survey (INCA2) as well as data from a 2004 purchase panel of French households (SECODIP) were used to identify the core foods to be sampled. A total of 116 core foods on a national scale and 70 core foods on a regional scale were selected according to (1) the consumption data for adults and children, (2) their consumer rates, and (3) their high contribution to exposure to one or more contaminants of interest. Foods were collected in eight French regions (36 cities) and prepared 'as consumed' to be analysed for their nutritional composition and contamination levels. A total of 20 280 different food products were purchased to make up the 1352 composite samples of core foods to be analysed for additives, environmental contaminants, pesticide residues, trace elements and minerals, mycotoxins and acrylamide. The establishment of such a sampling plan is essential for effective, high-quality monitoring of dietary exposure from a public health point of view.

Constraints on Inner Core Anisotropy Using Array Observations of P'P'

NASA Astrophysics Data System (ADS)

Frost, Daniel A.; Romanowicz, Barbara

2017-11-01

Recent studies of PKPdf travel times suggest strong anisotropy (4% or more) in the quasi-western inner core hemisphere. However, the availability of paths sampling at low angles to the Earth's rotation axis (the fast axis) is limited. To augment this sampling, we collected a travel time data set for the phase P'P'df (PKPPKPdf), for which at least one inner core leg is quasi-polar, at two high latitude seismic arrays. We find that the inferred anisotropy is weak (on the order of 0.5 to 1.5%), confirming previous results based on a much smaller P'P' data set. While previous models of inner core anisotropy required very strong alignment of anisotropic iron grains, our results are more easily explained by current dynamic models of inner core growth. We observe large travel time anomalies when one leg of P'P'df is along the South Sandwich to Alaska path, consistent with PKPdf observations, and warranting further investigation.

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

Geoconservation and scientific rock sampling: Call for geoethical education strategies

NASA Astrophysics Data System (ADS)

Druguet, Elena; Passchier, Cees W.; Pennacchioni, Giorgio; Carreras, Jordi

2013-04-01

Some geological outcrops have a special scientific or educational value, represent a geological type locality and/or have a considerable aesthetical/photographic value. Such important outcrops require appropriate management to safeguard them from potentially damaging and destructive activities. Damage done to such rock exposures can include drill sampling by geologist undertaken in the name of scientific advancement. In order to illustrate the serious damage scientific sampling can do, we give some examples of outcrops from Western Europe, North America and South Africa, important to structural geology and petrology, where sampling was undertaken by means of drilling methods without any protective measures. After the rock coring, the aesthetic and photographic value of these delicate outcrops has decreased considerably. Unfortunately, regulation and protection mechanisms and codes of conduct can be ineffective. The many resources of geological information available to the geoscientist community (e.g. via Internet, such as outcrops stored in websites like "Outcropedia") promote access to sites of geological interest, but can also have a negative effect on their conservation. Geoethical education on rock sampling is therefore critical for conservation of the geological heritage. Geoethical principles and educational actions are aimed to be promoted at different levels to improve geological sciences development and to enhance conservation of important geological sites. Ethical protocols and codes of conduct should include geoconservation issues, being explicit about responsible sampling. Guided and inspired by the UK Geologists's Association "Code of Conduct for Rock Coring" (MacFadyen, 2010), we present a tentative outline requesting responsible behaviour: » Drill sampling is particularly threatening because it has a negative visual impact, whilst it is often unnecessary. Before sampling, geologists should think about the question "is drill sampling necessary for

Multivariate analysis and geochemical approach for assessment of metal pollution state in sediment cores.

PubMed

Jamshidi-Zanjani, Ahmad; Saeedi, Mohsen

2017-07-01

Vertical distribution of metals (Cu, Zn, Cr, Fe, Mn, Pb, Ni, Cd, and Li) in four sediment core samples (C 1 , C 2 , C 3 , and C 4 ) from Anzali international wetland located southwest of the Caspian Sea was examined. Background concentration of each metal was calculated according to different statistical approaches. The results of multivariate statistical analysis showed that Fe and Mn might have significant role in the fate of Ni and Zn in sediment core samples. Different sediment quality indexes were utilized to assess metal pollution in sediment cores. Moreover, a new sediment quality index named aggregative toxicity index (ATI) based on sediment quality guidelines (SQGs) was developed to assess the degree of metal toxicity in an aggregative manner. The increasing pattern of metal pollution and their toxicity degree in upper layers of core samples indicated increasing effects of anthropogenic sources in the study area.

Improvement of core drill methods

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

Gatz, J.L.

1975-07-01

This report documents results of a program to evaluate effectiveness of more or less conventional subsurface samplers in obtaining representative and undisturbed samples of noncohesive alluvial materials containing large quantities of gravels and cobbles. This is the first phase of a research program to improve core drill methods. Samplers evaluated consisted of the Lawrence Livermore Laboratory membrane sampler, 4-in. Denison sampler, 6-in. Dension sampler, 5-in. Modified Denison sampler, and 3-in. thinwall drive tube. Small representative samples were obtained with the Dension samplers; no undisturbed samples were obtained. The field work was accomplished in the Rhodes Canyon area, White Sands Misslemore » Range, New Mexico.« less

Teacher Efficacy Beliefs: A Case Study Investigation of Core Curriculum

ERIC Educational Resources Information Center

Brown, Natalie Marie

2017-01-01

The purpose of this qualitative case study was to understand how utilizing the Core Knowledge Sequence and aligned curricular resources influenced teachers' perceived self-efficacy for a sample of Arizona elementary charter school teachers. The sample for this study was a convenience sample of 15 elementary teachers, who were currently…

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.

Drilling the Thuringian Syncline, Germany: core processing during the INFLUINS scientific deep drilling campaign

NASA Astrophysics Data System (ADS)

Abratis, Michael; Methe, Pascal; Aehnelt, Michaela; Kunkel, Cindy; Beyer, Daniel; Kukowski, Nina; Totsche, Kai Uwe

2014-05-01

Deep drilling of the central Thuringian Syncline was carried out in order to gather substantial knowledge of subsurface fluid dynamics and fluid rock interaction within a sedimentary basin. The final depth of the borehole was successfully reached at 1179 m, just a few meters above the Buntsandstein - Zechstein boundary. One of the aspects of the scientific drilling was obtaining sample material from different stratigraphic units for insights in genesis, rock properties and fluid-rock interactions. Parts of the section were cored whereas cuttings provide record of the remaining units. Coring was conducted in aquifers and their surrounding aquitards, i.e. parts of the Upper Muschelkalk (Trochitenkalk), the Middle Muschelkalk, the Upper Buntsandstein (Pelitrot and Salinarrot) and the Middle Buntsandstein. In advance and in cooperation with the GFZ Potsdam team "Scientific Drilling" core handling was discussed and a workflow was developed to ensure efficient and appropriate processing of the valuable core material and related data. Core curation including cleaning, fitting, marking, measuring, cutting, boxing, photographing and unrolled scanning using a DMT core scanner was carried out on the drilling site in Erfurt. Due care was exercised on samples for microbiological analyses. These delicate samples were immediately cut when leaving the core tube and stored within a cooling box at -78°C. Special software for data input was used developed by smartcube GmbH. Advantages of this drilling information system (DIS) are the compatibility with formats of international drilling projects from the IODP and ICDP drilling programs and thus options for exchanges with the international data bases. In a following step, the drill cores were brought to the national core repository of the BGR in Berlin Spandau where the cores were logged for their physical rock properties using a GeoTek multi sensor core logger (MSCL). After splitting the cores into a working and archive half, the

Ultrasound phase rotation beamforming on multi-core DSP.

PubMed

Ma, Jieming; Karadayi, Kerem; Ali, Murtaza; Kim, Yongmin

2014-01-01

Phase rotation beamforming (PRBF) is a commonly-used digital receive beamforming technique. However, due to its high computational requirement, it has traditionally been supported by hardwired architectures, e.g., application-specific integrated circuits (ASICs) or more recently field-programmable gate arrays (FPGAs). In this study, we investigated the feasibility of supporting software-based PRBF on a multi-core DSP. To alleviate the high computing requirement, the analog front-end (AFE) chips integrating quadrature demodulation in addition to analog-to-digital conversion were defined and used. With these new AFE chips, only delay alignment and phase rotation need to be performed by DSP, substantially reducing the computational load. We implemented the delay alignment and phase rotation modules on a Texas Instruments C6678 DSP with 8 cores. We found it takes 200 μs to beamform 2048 samples from 64 channels using 2 cores. With 4 cores, 20 million samples can be beamformed in one second. Therefore, ADC frequencies up to 40 MHz with 2:1 decimation in AFE chips or up to 20 MHz with no decimation can be supported as long as the ADC-to-DSP I/O requirement can be met. The remaining 4 cores can work on back-end processing tasks and applications, e.g., color Doppler or ultrasound elastography. One DSP being able to handle both beamforming and back-end processing could lead to low-power and low-cost ultrasound machines, benefiting ultrasound imaging in general, particularly portable ultrasound machines. Copyright © 2013 Elsevier B.V. All rights reserved.

Inexpensive, easy-to-construct suction coring devices usable from small boats

USGS Publications Warehouse

Onuf, Christopher P.; Chapman, Duane C.; Rizzo, William M.

1996-01-01

Collection of sediment cores in depths of 1-5 m is difficult with traditional sampling gear. Here we describe three suction coring devices constructed with readily available plumbing supplies and parts easily made from acrylic plastic and silicone sealant. The samplers have been used successfully in sediments ranging from coarse sands and shell hash to muds, highly organic deposits, and dense clays. Successful applications have ranged from contaminants analysis, toxicity testing, seagrass mapping, and assessment of sediment-microfloral interactions to sampling the infauna of surf-swept beaches.

Historical ecology of the northern Adriatic Sea: Field methods and coring device

NASA Astrophysics Data System (ADS)

Haselmair, Alexandra; Gallmetzer, Ivo; Tomasovych, Adam; Stachowitsch, Michael; Zuschin, Martin

2014-05-01

For an ongoing study on the historical ecology of the northern Adriatic Sea, the objective was to retrieve a high number of sediment cores at seven sampling stations spread across the entire basin. One set of cores is intended for sediment analyses including radiometric Pb-sediment-dating, grain size, TOC, TAC and heavy metal analyses. The other set of cores delivered enough shelly remains of endo- or epibenthic hard part producers (e.g. molluscs, crustaceans, echinoderms) to enable the reconstruction of death assemblages in core layers from top to bottom. The down-core changes of such assemblages record ecological shifts in a marine environment that has endured strong human impacts over several centuries. A 1.5 m-long core could, according to the available sedimentation data for the area, cover up to 2000 or even more years of ecological history. The coring method had to meet the following requirements: a) deliver 1.5-m-long cores from different sediment settings (mud to sand, reflecting a wide range of benthic habitats in the northern Adriatic); b) enable quick and easy deployment to ensure that multiple cores can be taken at the individual sampling stations within a short time; c) be relatively affordable and allow handling by the researchers themselves, potentially using a small vessel in order to further contain the operating costs. Two types of UWITEC™ piston corers were used to meet these requirements. A model with 90 mm of diameter (samples for sediment analysis) and another one with 160 mm, specifically designed to obtain the large amount of material needed for shell analysis, successfully delivered a total of 54 cores. The device consists of a stabilizing tripod and the interchangeable coring cylinders. It is equipped with a so-called hammer action that makes it possible, at least for the smaller cylinder, to penetrate even harder sediments. A closing mechanism of the corer retains the sediment in the cylinder upon extraction; it works either

Nitrogen partitioning during core-mantle differentiation

NASA Astrophysics Data System (ADS)

Speelmanns, I. M.; Schmidt, M. W.; Liebske, C.

2016-12-01

This study investiagtes nitrogen partitioing between metal and silicate melts as relevant for core segregation during the accretion of planetesimals into the Earth. On present day Earth, N belongs to the most important elements, as it is one of the key constituents of our atmosphere and forms the basis of life. However, the geochemistry of N, i.e. its distribution and isotopic fractionation between Earth's deep reservoirs is not well constrained. In order to determine the partitioning behaviour of N, a centrifuging piston cylinder was used to euqilibrate and then gravitationally separate metal-silicate melt pairs at 1250 °C, 1 GPa over the range of oxygen fugacities thought to have prevailied druing core segreagtion (IW-4 to IW). Complete segregation of the two melts was reached within 3 hours at 1000 g, the interface showing a nice meniscus The applied double capsule technique, using an outer metallic and inner non-metallic (mostly graphite) capsule, minimizes volatile loss over the course of the experiment compared to single non-metallic capsules. The two quenched melts were cut apart, cleaned at the outside and N concentrations of the melts were analysed on bulk samples by an elemental analyser. Nevertheless, the low amount of sample material and the N yield in the high pressure experiments required the developement of new analytical routines. Despite these experimental and analytical difficulties, we were able to determine a DNmetal/silicateof 13±0.25 at IW-1, N partitioning into the core froming metal. The few availible literature data [1],[2] suggest that N changes its compatibility favoring the silicate melt or magma ocean at around IW-2.5. In order to asses how much N may effectively be contained in the core and the silicate Earth, experiments characterizing N behaviour over the entire range of core formation condtitions are well under way. [1] Kadik et al., (2011) Geochemistry International 49.5: 429-438. [2] Roskosz et al., (2013) GCA 121: 15-28.

Preparation and characterisation of core-shell CNTs@MIPs nanocomposites and selective removal of estrone from water samples.

PubMed

Gao, Ruixia; Su, Xiaoqian; He, Xiwen; Chen, Langxing; Zhang, Yukui

2011-01-15

This paper reports the preparation of carbon nanotubes (CNTs) functionalized with molecularly imprinted polymers (MIPs) for advanced removal of estrone. CNTs@Est-MIPs nanocomposites with a well-defined core-shell structure were obtained using a semi-covalent imprinting strategy, which employed a thermally reversible covalent bond at the surface of silica-coated CNTs for a large-scale production. The morphology and structure of the products were characterised by transmission electron microscopy and Fourier transform infrared spectroscopy. The adsorption properties were demonstrated by equilibrium rebinding experiments and Scatchard analysis. The results demonstrate that the imprinted nanocomposites possess favourable selectivity, high capacity and fast kinetics for template molecule uptake, yielding an adsorption capacity of 113.5 μmol/g. The synthetic process is quite simple, and the different batches of synthesized CNTs@Est-MIPs nanocomposites showed good reproducibility in template binding. The feasibility of removing estrogenic compounds from environmental water using the CNTs@Est-MIPs nanocomposites was demonstrated using water samples spiked with estrone. Copyright © 2010 Elsevier B.V. All rights reserved.

Geothermal alteration of basaltic core from the Snake River Plain, Idaho

NASA Astrophysics Data System (ADS)

Sant, Christopher J.

The Snake River Plain is located in the southern part of the state of Idaho. The eastern plain, on which this study focuses, is a trail of volcanics from the Yellowstone hotspot. Three exploratory geothermal wells were drilled on the Snake River Plain. This project analyzes basaltic core from the first well at Kimama, north of Burley, Idaho. The objectives of this project are to establish zones of geothermal alteration and analyze the potential for geothermal power production using sub-aquifer resources on the axial volcanic zone of the Snake River Plain. Thirty samples from 1,912 m of core were sampled and analyzed for clay content and composition using X-ray diffraction. Observations from core samples and geophysical logs are also used to establish alteration zones. Mineralogical data, geophysical log data and physical characteristics of the core suggest that the base of the Snake River Plain aquifer at the axial zone is located 960 m below the surface, much deeper than previously suspected. Swelling smectite clay clogs pore spaces and reduces porosity and permeability to create a natural base to the aquifer. Increased temperatures favor the formation of smectite clay and other secondary minerals to the bottom of the hole. Below 960 m the core shows signs of alteration including color change, formation of clay, and filling of other secondary minerals in vesicles and fractured zones of the core. The smectite clay observed is Fe-rich clay that is authigenic in some places. Geothermal power generation may be feasible using a low temperature hot water geothermal system if thermal fluids can be attained near the bottom of the Kimama well.

Operation of a Public Geologic Core and Sample Repository in Houstion, Texas

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

Scott Tinker; Beverly DeJarnett

2007-07-31

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 FY05 and FY06 technical progress reports 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 now houses over 725,000 boxes of rock material (as of January 2008), and has space to hold approximately 300,000 more boxes. Use of the facility has remained strong; the number of patrons averaged over 100 per month from June 1, 2006 to October 2007, and 90,000 boxes of core were donated to, and received by, the HRC during this time. 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. These numbers are in addition to the numerous daily requests from patrons desiring to have rock material shipped offsite to their own offices. The BEG/HRC secured several substantial donations of rock materials and cash totaling approximatelymore » $2.2 million during the 2005-2006 operating period. All of these funds went directly into an endowment that UT is building in order to operate the HRC primarily off a portion of the interest generated by the fund. Specific details regarding the funds in the endowment are addressed in a table later in this report. Outreach during 2005 and 2006 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 a major donation of rock material and cash in order to approach full funding of the HRC endowment. Thanks to donations

Geochemical Constraints on Core-Mantle Interaction from Fe/Mn Ratios

NASA Astrophysics Data System (ADS)

Humayun, M.; Qin, L.

2003-12-01

The greater density of liquid iron alloy, and its immiscibility with silicate, maintains the physical separation of the core from the mantle. There are no a priori reasons, however, why the Earth's mantle should be chemically isolated from the core. Osmium isotopic variations in mantle plumes have been interpreted in terms of interaction between outer core and the source regions of deep mantle plumes. If chemical transport occurs across the core-mantle boundary its mechanism remains to be established. The Os isotope evidence has also been interpreted as the signatures of subducted Mn-sediments, which are known to have relatively high Pt/Os. In the mantle, Fe occurs mainly as the divalent ferrous ion, and Mn occurs solely as a divalent ion, and both behave in a geochemically coherent manner because of similarity in ionic charge and radius. Thus, the Fe/Mn ratio is a planetary constant insensitive to processes of mantle differentiation by partial melting. Two processes may perturb the ambient mantle Fe/Mn of 60: a) the subduction of Mn-sediments should decrease the Fe/Mn ratio in plume sources, while b) chemical transport from the outer core may increase the Fe/Mn ratio. The differentiation of the liquid outer core to form the solid inner core may increase abundances of the light element constituents (FeS, FeO, etc.) to the point of exsolution from the core at the CMB. The exact rate of this process is determined by the rate of inner core growth. Two end-member models include 1) inner core formation mainly prior to 3.5 Ga with heat release dominated by radioactive sources, or 2) inner core formation occurring mainly in the last 1.5 Ga with heat release dominated by latent heat. This latter model would imply large fluxes of Fe into the sources of modern mantle plumes. Existing Fe/Mn data for Gorgona and Hawaiian samples place limits on both these processes. We describe a new procedure for the precise determination of the Fe/Mn ratio in magmatic rocks by ICP-MS. This

Bacterial community structure in the hyperarid core of the Atacama Desert, Chile

USGS Publications Warehouse

Drees, Kevin P.; Neilson, Julia W.; Betancourt, Julio L.; Quade, Jay; Henderson, David A.; Pryor, Barry M.; Maier, Raina M.

2006-01-01

Soils from the hyperarid Atacama Desert of northern Chile were sampled along an east-west elevational transect (23.75 to 24.70 degrees S) through the driest sector to compare the relative structure of bacterial communities. Analysis of denaturing gradient gel electrophoresis (DGGE) profiles from each of the samples revealed that microbial communities from the extreme hyperarid core of the desert clustered separately from all of the remaining communities. Bands sequenced from DGGE profiles of two samples taken at a 22-month interval from this core region revealed the presence of similar populations dominated by bacteria from the Gemmatimonadetes and Planctomycetes phyla.

Magnesium Content of the Core: an Experimental Study

NASA Astrophysics Data System (ADS)

Fiquet, G.; Badro, J.; Auzende, A.; Siebert, J.; Gregoryanz, E.; Guignot, N.

2006-12-01

There is still a considerable debate about which light element among sulfur, silicon, oxygen, carbon or hydrogen should be in the core [Poirier, Phys. Earth Planet. Int., 85, 319, 1994]. The nature and distribution of these elements is a standing problem of prime importance, since it controls the freezing point depression at the inner core boundary. In addition to these candidates, new elements have been recently proposed as iron alloying constituants for the core, such as magnesium [Dubrovinskaia et al., Phys. Rev. Lett., 95, 245502, 2005]. We present series of experiments carried out on hot-pressed samples of iron and periclase in a laser-heated diamond-anvil cell, combined with in situ X-ray diffraction analysis and ATEM examination of recovered samples. We show that even at megabar pressures the amount of magnesium released in iron from the equilibrium with magnesium oxide is marginal. This finding is at odds with the 10 at% of magnesium found by Dubrovinskaia et al. [2005] in an iron alloy made from the reaction between iron and a metallic magnesium foil. Our observations suggest that magnesium is unlikely to be an important light element in the Earth's core. In addition, we provide structural data for iron to 130 GPa in excess of 3000 K with reliable pressure and temperature measurements, which enable us to propose a new thermal equation of state for iron at megabar pressures.

Subsurface Sample Acquisition and Transfer Systems (SSATS)

NASA Astrophysics Data System (ADS)

Rafeek, S.; Gorevan, S. P.; Kong, K. Y.

2001-01-01

In the exploration of planets and small bodies, scientists will need the services of a deep drilling and material handling system to not only obtain the samples necessary for analyses but also to precisely transfer and deposit those samples in in-situ instruments on board a landed craft or rover. The technology for such a deep sampling system as the SSATS is currently been developed by Honeybee Robotics through a PIDDP effort. The SSATS has its foundation in a one-meter prototype (SATM) drill that was developed under the New Millenium Program for ST4/Champollion. Additionally the SSATS includes relevant coring technology form a coring drill (Athena Mini-Corer) developed for the Mars Sample Return Mission. These highly developed technologies along with the current PIDDP effort, is combined to produce a sampling system that can acquire and transfer samples from various depths. Additional information is contained in the original extended abstract.

Effects of Core Self-Evaluations on the Job Burnout of Nurses: The Mediator of Organizational Commitment

PubMed Central

Zhou, Yangen; Lu, Jiamei; Liu, Xianmin; Zhang, Pengcheng; Chen, Wuying

2014-01-01

Objective To explore the impact of Core self-evaluations on job burnout of nurses, and especially to test and verify the mediator role of organizational commitment between the two variables. Method Random cluster sampling was used to pick up participants sample, which consisted of 445 nurses of a hospital in Shanghai. Core self-evaluations questionnaire, job burnout scale and organizational commitment scale were administrated to the study participants. Results There are significant relationships between Core self-evaluations and dimensions of job burnout and organizational commitment. There is a significant mediation effect of organizational commitment between Core self-evaluations and job burnout. Conclusions To enhance nurses’ Core self-evaluations can reduce the incidence of job burnout. PMID:24755670

Heterogeneity of PTEN and ERG expression in prostate cancer on core needle biopsies: implications for cancer risk stratification and biomarker sampling.

PubMed

Shah, Rajal B; Bentley, James; Jeffery, Zach; DeMarzo, Angelo M

2015-05-01

ERG and PTEN biomarkers are increasingly being analyzed on prostate core biopsies (NBXs); ERG as a marker of clonality and number of separately arising tumor foci and PTEN for prognostic information. Yet, in patients with multiple biopsy cores positive for cancer (PCa), there is no standardized approach for interrogation of these biomarkers in terms of the number of positive cores to evaluate. A total of 194 NBX cases containing more than one positive core with cancer were evaluated for ERG overexpression and PTEN loss by immunostaining (immunohistochemistry) of all positive cores. ERG overexpression or PTEN loss in at least one cancer core was present in 111 (57%) and 69 (36%) cases respectively. ERG overexpression was significantly associated with PTEN loss (P < .0001), and PTEN loss was associated with a high Gleason score (P < .0001). Inter- and intra-tumor core staining heterogeneity for ERG overexpression occurred in 42% and 5% cases and for PTEN loss both intra- and inter-tumor core heterogeneity was 68%. PTEN staining was highly discordant between PCa sites regardless of laterality. When the Gleason score was non-uniform across PCa sites, the combination of cores showing the highest Gleason score and largest tumor volume provided the best representation of ERG overexpression (92%) and PTEN loss (98%). When grades were uniform across cancer sites, the highest tumor volume core was generally representative of ERG overexpression (90%) but was less representative for PTEN loss (76%). Our results suggest that knowledge of this heterogeneity is critical for developing optimal yet cost-effective strategies to identify these underlying molecular abnormalities. Copyright © 2015 Elsevier Inc. All rights reserved.

Identification of water-quality trends using sediment cores from Dillon Reservoir, Summit County, Colorado

USGS Publications Warehouse

Greve, Adrienne I.; Spahr, Norman E.; Van Metre, Peter C.; Wilson, Jennifer T.

2001-01-01

Since the construction of Dillon Reservoir, in Summit County, Colorado, in 1963, its drainage area has been the site of rapid urban development and the continued influence of historical mining. In an effort to assess changes in water quality within the drainage area, sediment cores were collected from Dillon Reservoir in 1997. The sediment cores were analyzed for pesticides, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and trace elements. Pesticides, PCBs, and PAHs were used to determine the effects of urban development, and trace elements were used to identify mining contributions. Water-quality and streambed-sediment samples, collected at the mouth of three streams that drain into Dillon Reservoir, were analyzed for trace elements. Of the 14 pesticides and 3 PCBs for which the sediment samples were analyzed, only 2 pesticides were detected. Low amounts of dichloro-diphenyldichloroethylene (DDE) and dichloro-diphenyldichloroethane (DDD), metabolites of dichlorodiphenyltrichloroethane (DDT), were found at core depths of 5 centimeters and below 15 centimeters in a core collected near the dam. The longest core, which was collected near the dam, spanned the entire sedimentation history of the reservoir. Concentrations of total combustion PAH and the ratio of fluoranthene to pyrene in the core sample decreased with core depth and increased over time. This relation is likely due to growth in residential and tourist populations in the region. Comparisons between core samples gathered in each arm of the reservoir showed the highest PAH concentrations were found in the Tenmile Creek arm, the only arm that has an urban area on its shores, the town of Frisco. All PAH concentrations, except the pyrene concentration in one segment in the core near the dam and acenaphthylene concentrations in the tops of three cores taken in the reservoir arms, were below Canadian interim freshwater sediment-quality guidelines. Concentrations of arsenic, cadmium

X-ray CT core imaging of Oman Drilling Project on D/V CHIKYU

NASA Astrophysics Data System (ADS)

Michibayashi, K.; Okazaki, K.; Leong, J. A. M.; Kelemen, P. B.; Johnson, K. T. M.; Greenberger, R. N.; Manning, C. E.; Harris, M.; de Obeso, J. C.; Abe, N.; Hatakeyama, K.; Ildefonse, B.; Takazawa, E.; Teagle, D. A. H.; Coggon, J. A.

2017-12-01

We obtained X-ray computed tomography (X-ray CT) images for all cores (GT1A, GT2A, GT3A and BT1A) in Oman Drilling Project Phase 1 (OmanDP cores), since X-ray CT scanning is a routine measurement of the IODP measurement plan onboard Chikyu, which enables the non-destructive observation of the internal structure of core samples. X-ray CT images provide information about chemical compositions and densities of the cores and is useful for assessing sample locations and the quality of the whole-round samples. The X-ray CT scanner (Discovery CT 750HD, GE Medical Systems) on Chikyu scans and reconstructs the image of a 1.4 m section in 10 minutes and produces a series of scan images, each 0.625 mm thick. The X-ray tube (as an X-ray source) and the X-ray detector are installed inside of the gantry at an opposing position to each other. The core sample is scanned in the gantry with the scanning rate of 20 mm/sec. The distribution of attenuation values mapped to an individual slice comprises the raw data that are used for subsequent image processing. Successive two-dimensional (2-D) slices of 512 x 512 pixels yield a representation of attenuation values in three-dimensional (3-D) voxels of 512 x 512 by 1600 in length. Data generated for each core consist of core-axis-normal planes (XY planes) of X-ray attenuation values with dimensions of 512 × 512 pixels in 9 cm × 9 cm cross-section, meaning at the dimensions of a core section, the resolution is 0.176 mm/pixel. X-ray intensity varies as a function of X-ray path length and the linear attenuation coefficient (LAC) of the target material is a function of the chemical composition and density of the target material. The basic measure of attenuation, or radiodensity, is the CT number given in Hounsfield units (HU). CT numbers of air and water are -1000 and 0, respectively. Our preliminary results show that CT numbers of OmanDP cores are well correlated to gamma ray attenuation density (GRA density) as a function of chemical

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

Core Requirements for the Economics Major

ERIC Educational Resources Information Center

Petkus, Marie; Perry, John J.; Johnson, Bruce K.

2014-01-01

In this article, the authors are the first to describe the core economics curriculum requirements for economics majors at all American colleges and universities, as opposed to a sample of institutions. Not surprisingly, principles of economics is nearly universally required and implemented as a two-semester course in 85 percent of economics major…

Variable depth core sampler

DOEpatents

Bourgeois, Peter M.; Reger, Robert J.

1996-01-01

A variable depth core sampler apparatus comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member.

Geologic logs of geotechnical cores from the subsurface Sacramento-San Joaquin Delta, California

USGS Publications Warehouse

Maier, Katherine L.; Ponti, Daniel J.; Tinsley, John C.; Gatti, Emma; Pagenkopp, Mark

2014-01-01

This report presents and summarizes descriptive geologic logs of geotechnical cores collected from 2009–12 in the Sacramento–San Joaquin Delta, California, by the California Department of Water Resources. Graphic logs are presented for 1,785.7 ft of retained cores from 56 borehole sites throughout the Sacramento-San Joaquin Delta. Most core sections are from a depth of ~100–200 feet. Cores primarily contain mud, silt, and sand lithologies. Tephra (volcanic ash and pumice), paleosols, and gravels are also documented in some core sections. Geologic observations contained in the core logs in this report provide stratigraphic context for subsequent sampling and data for future chronostratigraphic subsurface correlations.

High-resolution probing of inner core structure with seismic interferometry

NASA Astrophysics Data System (ADS)

Huang, Hsin-Hua; Lin, Fan-Chi; Tsai, Victor C.; Koper, Keith D.

2015-12-01

Increasing complexity of Earth's inner core has been revealed in recent decades as the global distribution of seismic stations has improved. The uneven distribution of earthquakes, however, still causes a biased geographical sampling of the inner core. Recent developments in seismic interferometry, which allow for the retrieval of core-sensitive body waves propagating between two receivers, can significantly improve ray path coverage of the inner core. In this study, we apply such earthquake coda interferometry to 1846 USArray stations deployed across the U.S. from 2004 through 2013. Clear inner core phases PKIKP2 and PKIIKP2 are observed across the entire array. Spatial analysis of the differential travel time residuals between the two phases reveals significant short-wavelength variation and implies the existence of strong structural variability in the deep Earth. A linear N-S trending anomaly across the middle of the U.S. may reflect an asymmetric quasi-hemispherical structure deep within the inner core with boundaries of 99°W and 88°E.

Data management integration for biomedical core facilities

NASA Astrophysics Data System (ADS)

Zhang, Guo-Qiang; Szymanski, Jacek; Wilson, David

2007-03-01

We present the design, development, and pilot-deployment experiences of MIMI, a web-based, Multi-modality Multi-Resource Information Integration environment for biomedical core facilities. This is an easily customizable, web-based software tool that integrates scientific and administrative support for a biomedical core facility involving a common set of entities: researchers; projects; equipments and devices; support staff; services; samples and materials; experimental workflow; large and complex data. With this software, one can: register users; manage projects; schedule resources; bill services; perform site-wide search; archive, back-up, and share data. With its customizable, expandable, and scalable characteristics, MIMI not only provides a cost-effective solution to the overarching data management problem of biomedical core facilities unavailable in the market place, but also lays a foundation for data federation to facilitate and support discovery-driven research.

Experimental evidence of body centered cubic iron in Earth's core

NASA Astrophysics Data System (ADS)

Hrubiak, R.; Meng, Y.; Shen, G.

2017-12-01

The Earth's core is mainly composed of iron. While seismic evidence has shown a liquid outer core and a solid inner core, the crystalline nature of the solid iron at the core condition remains debated, largely due to the difficulties in experimental determination of exact polymorphs at corresponding pressure-temperature conditions. We have examined crystal structures of iron up to 220 GPa and 6000 K with x-ray diffraction using a double-sided laser heating system at HPCAT, Advanced Photon Source. The iron sample is confined in a small chamber surrounded by single crystal MgO. The laser power can be modulated together with temperature measurements. The modulated heating of iron in an MgO single crystal matrix allows for microstructure analysis during heating and after the sample is quenched. We present experimental evidence of a body-centered-cubic (BCC) iron from about 100 GPa and 3000 K to at least 220 GPa and 4000 K. The observed BCC phase may be consistent with a theoretically predicted BCC phase that is dynamically stable in similar pressure-temperature conditions [1]. We will discuss the stability region of the BCC phase and the melting curve of iron and their implications in the nature of the Earth's inner core. References: A. B. Belonoshko et al., Nat. Geosci., 1-6 (2017).

Preliminary organic analyses of the DSDP /JOIDES/ cores - Legs V-IX.

NASA Technical Reports Server (NTRS)

Simoneit, B. R.; Burlingame, A. L.

1972-01-01

Descriptions of the methods used and results obtained in analyses of deep sea drilling cores. The analyses were performed in two phases (differing in degree of particularization) depending on the amount of core sample available. The results are presented in relation to the ages and to the fossil fauna and flora of the sediments.

Tank 241-T-204, core 188 analytical results for the final report

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

Nuzum, J.L.

TANK 241-T-204, CORE 188, ANALYTICAL RESULTS FOR THE FINAL REPORT. This document is the final laboratory report for Tank 241 -T-204. Push mode core segments were removed from Riser 3 between March 27, 1997, and April 11, 1997. Segments were received and extruded at 222-8 Laboratory. Analyses were performed in accordance with Tank 241-T-204 Push Mode Core Sampling and analysis Plan (TRAP) (Winkleman, 1997), Letter of instruction for Core Sample Analysis of Tanks 241-T-201, 241- T-202, 241-T-203, and 241-T-204 (LAY) (Bell, 1997), and Safety Screening Data Qual@ Objective (DO) ODukelow, et al., 1995). None of the subsamples submitted for totalmore » alpha activity (AT) or differential scanning calorimetry (DC) analyses exceeded the notification limits stated in DO. The statistical results of the 95% confidence interval on the mean calculations are provided by the Tank Waste Remediation Systems Technical Basis Group and are not considered in this report.« less

Physical properties of two core samples from Well 34-9RD2 at the Coso geothermal field, California

USGS Publications Warehouse

Morrow, C.A.; Lockner, D.A.

2006-01-01

The Coso geothermal field, located along the Eastern California Shear Zone, is composed of fractured granitic rocks above a shallow heat source. Temperatures exceed 640 ?F (~338 ?C) at a depth of less than 10000 feet (3 km). Permeability varies throughout the geothermal field due to the competing processes of alteration and mineral precipitation, acting to reduce the interconnectivity of faults and fractures, and the generation of new fractures through faulting and brecciation. Currently, several hot regions display very low permeability, not conducive to the efficient extraction of heat. Because high rates of seismicity in the field indicate that the area is highly stressed, enhanced permeability can be stimulated by increasing the fluid pressure at depth to induce faulting along the existing network of fractures. Such an Enhanced Geothermal System (EGS), planned for well 46A-19RD, would greatly facilitate the extraction of geothermal fluids from depth by increasing the extent and depth of the fracture network. In order to prepare for and interpret data from such a stimulation experiment, the physical properties and failure behavior of the target rocks must be fully understood. Various diorites and granodiorites are the predominant rock types in the target area of the well, which will be pressurized from 10000 feet measured depth (MD) (3048m MD) to the bottom of the well at 13,000 feet MD (3962 m MD). Because there are no core rocks currently available from well 46A-19RD, we report here on the results of compressive strength, frictional sliding behavior, and elastic measurements of a granodiorite and diorite from another well, 34-9RD2, at the Coso site. Rocks cored from well 34-9RD2 are the deepest samples to date available for testing, and are representative of rocks from the field in general.

Distribution of pesticide residues in soil and uncertainty of sampling.

PubMed

Suszter, Gabriela K; Ambrus, Árpád

2017-08-03

Pesticide residues were determined in about 120 soil cores taken randomly from the top 15 cm layer of two sunflower fields about 30 days after preemergence herbicide treatments. Samples were extracted with acetone-ethyl acetate mixture and the residues were determined with GC-TSD. Residues of dimethenamid, pendimethalin, and prometryn ranged from 0.005 to 2.97 mg/kg. Their relative standard deviations (CV) were between 0.66 and 1.13. The relative frequency distributions of residues in soil cores were very similar to those observed in root and tuber vegetables grown in pesticide treated soils. Based on all available information, a typical CV of 1.00 was estimated for pesticide residues in primary soil samples (soil cores). The corresponding expectable relative uncertainty of sampling is 20% when composite samples of size 25 are taken. To obtain a reliable estimate of the average residues in the top 15 cm layer of soil of a field up to 8 independent replicate random samples should be taken. To obtain better estimate of the actual residue level of the sampled filed would be marginal if larger number of samples were taken.

Critical Fracture Toughness Measurements of an Antarctic Ice Core

NASA Astrophysics Data System (ADS)

Christmann, Julia; Müller, Ralf; Webber, Kyle; Isaia, Daniel; Schader, Florian; Kippstuhl, Sepp; Freitag, Johannes; Humbert, Angelika

2014-05-01

Fracture toughness is a material parameter describing the resistance of a pre-existing defect in a body to further crack extension. The fracture toughness of glacial ice as a function of density is important for modeling efforts aspire to predict calving behavior. In the presented experiments this fracture toughness is measured using an ice core from Kohnen Station, Dronning Maud Land, Antarctica. The samples were sawed in an ice lab at the Alfred Wegener Institute in Bremerhaven at -20°C and had the dimensions of standard test samples with thickness 14 mm, width 28 mm and length 126 mm. The samples originate from a depth of 94.6 m to 96 m. The grain size of the samples was also identified. The grain size was found to be rather uniform. The critical fracture toughness is determined in a four-point bending approach using single edge V-notch beam samples. The initial notch length was around 2.5 mm and was prepared using a drilling machine. The experimental setup was designed at the Institute of Materials Science at Darmstadt. In this setup the force increases linearly, until the maximum force is reached, where the specific sample fractures. This procedure was done in an ice lab with a temperature of -15°C. The equations to calculate the fracture toughness for pure bending are derived from an elastic stress analysis and are given as a standard test method to detect the fracture toughness. An X-ray computer tomography (CT scanner) was used to determine the ice core densities. The tests cover densities from 843 kg m-3 to 871 kg m-3. Thereby the influence of the fracture toughness on the density was analyzed and compared to previous investigations of this material parameter. Finally the dependence of the measured toughness on thickness, width, and position in the core cross-section was investigated.

Core vocabulary of young children with Down syndrome.

PubMed

Deckers, Stijn R J M; Van Zaalen, Yvonne; Van Balkom, Hans; Verhoeven, Ludo

2017-06-01

The aim of this study was to develop a core vocabulary list for young children with intellectual disabilities between 2 and 7 years of age because data from this population are lacking in core vocabulary literature. Children with Down syndrome are considered one of the most valid reference groups for researching developmental patterns in children with intellectual disabilities; therefore, spontaneous language samples of 30 Dutch children with Down syndrome were collected during three different activities with multiple communication partners (free play with parents, lunch- or snack-time at home or at school, and speech therapy sessions). Of these children, 19 used multimodal communication, primarily manual signs and speech. Functional word use in both modalities was transcribed. The 50 most frequently used core words accounted for 67.2% of total word use; 16 words comprised core vocabulary, based on commonality. These data are consistent with similar studies related to the core vocabularies of preschoolers and toddlers with typical development, although the number of nouns present on the core vocabulary list was higher for the children in the present study. This finding can be explained by manual sign use of the children with Down syndrome and is reflective of their expressive vocabulary ages.

Carbon chemistry of the Apollo 15 and 16 deep drill cores

NASA Technical Reports Server (NTRS)

Wszolek, P. C.; Burlingame, A. L.

1973-01-01

The carbon chemistry of the Apollo 15 and 16 deep drill cores is a function of the surface exposure plus the chemical and mineralogical composition of the individual samples. The depth profiles of carbide and methane yields in the Apollo 15 core show a general decline with depth and correlate with the solar wind noble gas content, percentage agglutinates, track densities, and metallic iron. All horizons examined were exposed for a considerable time on the lunar surface. The Apollo 16 core samples show that chemical and mineralogical composition plays an important role in determining the nature of carbide-like material present in the fines. The higher aluminum and calcium contents and lower iron contents of highlands material result in carbide-like material yielding less CD4 and more C2D2 (deuteroacetylene) upon DF acid dissolution.

Molecular Diagnostics of the Internal Motions of Massive Cores

NASA Astrophysics Data System (ADS)

Pineda, Jorge; Velusamy, T.; Goldsmith, P.; Li, D.; Peng, R.; Langer, W.

2009-12-01

We present models of the internal kinematics of massive cores in the Orion molecular cloud. We use a sample of cores studied by Velusamy et al. (2008) that show red, blue, and no asymmetry in their HCO+ line profiles in equal proportion, and which therefore may represent a sample of cores in different kinematic states. We use the radiative transfer code RATRAN (Hogerheijde & van der Tak 2000) to model several transitions of HCO+ and H13CO+ as well as the dust continuum emission, of a spherical model cloud with radial density, temperature, and velocity gradients. We find that an excitation and velocity gradients are prerequisites to reproduce the observed line profiles. We use the dust continuum emission to constrain the density and temperature gradients. This allows us to narrow down the functional forms of the velocity gradient giving us the opportunity to test several theoretical predictions of velocity gradients produced by the effect of magnetic fields (e.g. Tassis et. al. 2007) and turbulence (e.g. Vasquez-Semanedi et al 2007).

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

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

Determination of phthalic acid esters in water samples using core-shell poly(dopamine) magnetic nanoparticles and gas chromatography tandem mass spectrometry.

PubMed

González-Sálamo, Javier; Socas-Rodríguez, Bárbara; Hernández-Borges, Javier; Rodríguez-Delgado, Miguel Ángel

2017-12-29

In this work, the first application of core-shell poly(dopamine) magnetic nanoparticles as sorbent for the extraction of a group of eleven phthalic acid esters of interest (i.e. diethyl phthalate (DEP), dipropyl phthalate (DPP), dibutyl phthalate (DBP), bis-isopentyl phthalate (DIPP), bis-n-pentyl phthalate (DNPP), benzylbutyl phthalate (BBP), dicyclohexyl phthalate (DCHP), di-(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DNOP), diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP)) and one adipate (bis (2-ethylhexyl) adipate, DEHA) from different water samples (Milli-Q, mineral, tap, pond and waste water) is proposed. Analysis were carried out by gas chromatography triple quadrupole tandem mass spectrometry. Parameters that affect the extraction performance were optimized following a step by step approach, being the optimum conditions the extraction of water at pH 6, with 60mg of sorbent and the elution with 6mL of dichloromethane. The methodology was validated for the five selected water samples using DBP-d 4 as internal standard. Determination coefficients of matrix-matched calibration curves were above 0.9904 in all cases while relative recovery values ranged between 71 and 120%, with relative standard deviation values below 19%. The limits of quantification of the method ranged between 9 and 20ng/L. Matrix effects were found for most analytes and water samples. Real water samples were also analyzed, finding DEP and DBP at concentrations below 4.20 and 1.23μg/L, respectively, in mineral, tap and waste water. DCHP, DEHP and BBP were also found in some of the samples at concentrations below the LOQs of the method. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Physics Envy: Psychologists' Perceptions of Psychology and Agreement about Core Concepts

ERIC Educational Resources Information Center

Howell, Jennifer L.; Collisson, Brian; King, Kelly M.

2014-01-01

This study assessed the nature of psychology and its consensus regarding core content. We hypothesized that psychology possesses little agreement regarding its core content areas and thus may "envy" more canonical sciences, such as physics. Using a global sample, we compared psychologists' and physicists' perceptions regarding…

Planktic foraminifer census data from Northwind Ridge Core 5, Arctic Ocean

USGS Publications Warehouse

Foley, Kevin M.; Poore, Richard Z.

1991-01-01

The U.S. Geological Survey recovered 9 piston cores from the Northwind Ridge in the Canada Basin of the Arctic Ocean from a cruise of the USCGC Polar Star during 1988. Preliminary analysis of the cores suggests sediments deposited on Northwind Ridge preserve a detailed record of glacial and interglacial cycles for the last few hundred-thousand to one million years. This report includes quantitative data on foraminifers and selected sediment size-fraction data in samples from Northwind Ridge core PI-88AR P5.

The combined EarthScope data set at the IRIS DMC

NASA Astrophysics Data System (ADS)

Trabant, C.; Sharer, G.; Benson, R.; Ahern, T.

2007-12-01

The IRIS Data Management Center (DMC) is the perpetual archive and access point for an ever-increasing variety of geophysical data in terms of volume, geographic distribution and scientific value. A particular highlight is the combined data set produced by the EarthScope project. The DMC archives data from each of the primary components: USArray, the Plate Boundary Observatory (PBO) & the San Andreas Fault Observatory at Depth (SAFOD). Growing at over 4.6 gigabytes per day, the USArray data set currently totals approximately 5 terabytes. Composed of four separate sub-components: the Permanent, Transportable, Flexible and Magnetotelluric Arrays, the USArray data set provides a multi-scale view of the western United States at present and the conterminous United States when it is completed. The primary data from USArray are in the form of broadband and short-period seismic recordings and magnetotelluric measurements. Complementing the data from USArray are the short- period, borehole seismic data and borehole and laser strain data from PBO. The DMC also archives the high- resolution seismic data from instruments in the SAFOD main and pilot drill holes. The SAFOD seismic data is available in two forms: lower-rate monitoring channels sampled at 250 hertz and full resolution channels varying between 1 and 4 kilohertz. Beyond data collection and archive management the DMC performs value-added functions. All data arriving at the DMC as real-time data streams are processed by QUACK, an automated Quality Control (QC) system. All the measurements made by this system are stored in a database and made available to data contributors and users via a web interface including customized report generation. In addition to the automated QC measurements, quality control is performed on USArray data at the DMC by a team of analysts. The primary functions of the analysts are to routinely report data quality assessment to the respective network operators and log serious, unfixable data

Magnetization measurements and XMCD studies on ion irradiated iron oxide and core-shell iron/iron-oxide nanomaterials

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

Kaur, Maninder; Qiang, You; Jiang, Weilin

2014-12-02

Magnetite (Fe3O4) and core-shell iron/iron-oxide (Fe/Fe3O4) nanomaterials prepared by a cluster deposition system were irradiated with 5.5 MeV Si2+ ions and the structures determined by x-ray diffraction as consisting of 100% magnetite and 36/64 wt% Fe/FeO, respectively. However, x-ray magnetic circular dichroism (XMCD) indicates similar surfaces in the two samples, slightly oxidized and so having more Fe3+ than the expected magnetite structure, with XMCD intensity much lower for the irradiated core-shell samples indicating weaker magnetism. X-ray absorption spectroscopy (XAS) data lack the signature for FeO, but the irradiated core-shell system consists of Fe-cores with ~13 nm of separating oxide crystallite,more » so it is likely that FeO exists deeper than the probe depth of the XAS (~5 nm). Exchange bias (Hex) for both samples becomes increasingly negative as temperature is lowered, but the irradiated Fe3O4 sample shows greater sensitivity of cooling field on Hex. Loop asymmetries and Hex sensitivities of the irradiated Fe3O4 sample are due to interfaces and interactions between grains which were not present in samples before irradiation as well as surface oxidation. Asymmetries in the hysteresis curves of the irradiated core/shell sample are related to the reversal mechanism of the antiferromagnetic FeO and possibly some near surface oxidation.« less

Comparison of the retention of 5 core materials supported by a dental post.

PubMed

Gu, Steven; Isidro, Mario; Deutsch, Allan S; Musikant, Barry L

2006-01-01

This study evaluated the retention of dental post heads (No. 2 Flexi-Post) embedded in 5 core materials (1 automix resin composite, 2 hand-mixed resin composites, and 2 glass ionomers). Samples were prepared by embedding post heads in 4.5-mm-thick disks of core material. The resin composite materials provided significantly more retention than the glass-ionomer-based materials. The post head retention of the automix resin composite was comparable to that of the hand-mixed resin composites. Unlike the resin composite samples, all the glass-ionomer samples fractured during testing. This is an unacceptable condition for a clinically successful restoration.

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

Reconstructed plutonium fallout in the GV7 firn core from Northern Victoria Land, East Antarctica

NASA Astrophysics Data System (ADS)

Hwang, H.; Han, Y.; Kang, J.; Lee, K.; Hong, S.; Hur, S. D.; Narcisi, B.; Frezzotti, M.

2017-12-01

Atmospheric nuclear explosions during the period from the 1940s to the 1980s are the major anthropogenic source of plutonium (Pu) in the environment. In this work, we analyzed fg g-1 levels of artificial Pu, released predominantly by atmospheric nuclear weapons tests. We measured 351 samples which collected a 78 m-depth fire core at the site of GV7 (S 70°41'17.1", E 158°51'48.9", 1950 m a.s.l.), Northern Victoria Land, East Antarctica. To determine the Pu concentration in the samples, we used an inductively coupled plasma sector field mass spectrometry coupled with an Apex high-efficiency sample introduction system, which has the advantages of small sample consumption and simple sample preparation. We reconstructed the firn core Pu fallout record for the period after 1954 CE shows a significant fluctuation in agreement with past atmospheric nuclear testing. These data will contribute to ice core research by providing depth-age information.

Variable depth core sampler

DOEpatents

Bourgeois, P.M.; Reger, R.J.

1996-02-20

A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

Perfluoroalkyl substances and extractable organic fluorine in surface sediments and cores from Lake Ontario.

PubMed

Yeung, Leo W Y; De Silva, Amila O; Loi, Eva I H; Marvin, Chris H; Taniyasu, Sachi; Yamashita, Nobuyoshi; Mabury, Scott A; Muir, Derek C G; Lam, Paul K S

2013-09-01

Fourteen perfluoroalkyl substances (PFASs) including short-chain perfluorocarboxylates (PFCAs, C4-C6) and perfluoroalkane sulfonates (PFSAs, C4 and C6) were measured in surface sediment samples from 26 stations collected in 2008 and sediment core samples from three stations (Niagara, Mississauga, and Rochester basins) collected in 2006 in Lake Ontario. Perfluorooctanesulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorodecanoate (PFDA), and perfluoroundecanoate (PFUnDA) were detected in all 26 surface sediment samples, whereas perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonamide (FOSA), perfluorododecanoate (PFDoDA) and perfluorobutanoate (PFBA) were detected in over 70% of the surface sediment samples. PFOS was detected in all of the sediment core samples (range: 0.492-30.1ngg(-1) d.w.) over the period 1952-2005. The C8 to C11 PFCAs, FOSA, and PFBA increased in early 1970s. An overall increasing trend in sediment PFAS concentrations/fluxes from older to more recently deposited sediments was evident in the three sediment cores. The known PFCAs and PFSAs accounted for 2-44% of the anionic fraction of the extractable organic fluorine in surface sediment, suggesting that a large proportion of fluorine in this fraction remained unknown. Sediment core samples collected from Niagara basin showed an increase in unidentified organic fluorine in recent years (1995-2006). These results suggest that the use and manufacture of fluorinated organic compounds other than known PFCAs and PFSAs has diversified and increased. © 2013.

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

Establishing a Reliable Depth-Age Relationship for the Denali Ice Core

NASA Astrophysics Data System (ADS)

Wake, C. P.; Osterberg, E. C.; Winski, D.; Ferris, D.; Kreutz, K. J.; Introne, D.; Dalton, M.

2015-12-01

Reliable climate reconstruction from ice core records requires the development of a reliable depth-age relationship. We have established a sub-annual resolution depth-age relationship for the upper 198 meters of a 208 m ice core recovered in 2013 from Mt. Hunter (3,900 m asl), Denali National Park, central Alaska. The dating of the ice core was accomplished via annual layer counting of glaciochemical time-series combined with identification of reference horizons from volcanic eruptions and atmospheric nuclear weapons testing. Using the continuous ice core melter system at Dartmouth College, sub-seasonal samples have been collected and analyzed for major ions, liquid conductivity, particle size and concentration, and stable isotope ratios. Annual signals are apparent in several of the chemical species measured in the ice core samples. Calcium and magnesium peak in the spring, ammonium peaks in the summer, methanesulfonic acid (MSA) peaks in the autumn, and stable isotopes display a strong seasonal cycle with the most depleted values occurring during the winter. Thin ice layers representing infrequent summertime melt were also used to identify summer layers in the core. Analysis of approximately one meter sections of the core via nondestructive gamma spectrometry over depths from 84 to 124 m identified a strong radioactive cesium-137 peak at 89 m which corresponds to the 1963 layer deposited during extensive atmospheric nuclear weapons testing. Peaks in the sulfate and chloride record have been used for the preliminary identification of volcanic signals preserved in the ice core, including ten events since 1883. We are confident that the combination of robust annual layers combined with reference horizons provides a timescale for the 20th century that has an error of less than 0.5 years, making calibrations between ice core records and the instrumental climate data particularly robust. Initial annual layer counting through the entire 198 m suggests the Denali Ice

Historical Carbon Dioxide Record from the Siple Station Ice Core (1734-1983)

DOE Data Explorer

Neftel, A. [Physics Institute, University of Bern, Bern, Switzerland; Friedli, H. [Physics Institute, University of Bern, Bern, Switzerland; Moor, E. [Physics Institute, University of Bern, Bern, Switzerland; Lotscher, H. [Physics Institute, University of Bern, Bern, Switzerland; Oeschger, H. [Physics Institute, University of Bern, Bern, Switzerland; Siegenthaler, U. [Physics Institute, University of Bern, Bern, Switzerland; Stauffer, B. [Physics Institute, University of Bern, Bern, Switzerland

1994-09-01

Determinations of ancient atmospheric CO2 concentrations for Siple Station, located in West Antarctica, were derived from measurements of air occluded in a 200-m core drilled at Siple Station in the Antarctic summer of 1983-84. The core was drilled by the Polar Ice Coring Office in Nebraska and the Physics Institute at the University of Bern. The ice could be dated with an accuracy of approximately ±2 years to a depth of 144 m (which corresponds to the year 1834) by counting seasonal variations in electrical conductivity. Below that depth, the core was dated by extrapolation (Friedli et al. 1986). The gases from ice samples were extracted by a dry-extraction system, in which bubbles were crushed mechanically to release the trapped gases, and then analyzed for CO2 by infrared laser absorption spectroscopy or by gas chromatography (Neftel et al. 1985). After the ice samples were crushed, the gas expanded over a cold trap, condensing the water vapor at -80°C in the absorption cell. The analytical system was calibrated for each ice sample measurement with a standard mixture of CO2 in nitrogen and oxygen. For further details on the experimental and dating procedures, see Neftel et al. (1985), Friedli et al. (1986), and Schwander and Stauffer (1984).

Rock and Core Repository Coming Digital

NASA Astrophysics Data System (ADS)

Maicher, Doris; Fleischer, Dirk; Czerniak, Andreas

2016-04-01

In times of whole city centres being available by a mouse click in 3D to virtually walk through, reality sometimes becomes neglected. The reality of scientific sample collections not being digitised to the essence of molecules, isotopes and electrons becomes unbelievable to the upgrowing generation of scientists. Just like any other geological institute the Helmholtz Centre for Ocean Research GEOMAR accumulated thousands of specimen. The samples, collected mainly during marine expeditions, date back as far as 1964. Today GEOMAR houses a central geological sample collection of at least 17 000 m of sediment core and more than 4 500 boxes with hard rock samples and refined sample specimen. This repository, having been dormant, missed the onset of the interconnected digital age. Physical samples without barcodes, QR codes or RFID tags need to be migrated and reconnected, urgently. In our use case, GEOMAR opted for the International Geo Sample Number IGSN as the persistent identifier. Consequentially, the software CurationDIS by smartcube GmbH as the central component of this project was selected. The software is designed to handle acquisition and administration of sample material and sample archiving in storage places. In addition, the software allows direct embedding of IGSN. We plan to adopt IGSN as a future asset, while for the initial inventory taking of our sample material, simple but unique QR codes act as "bridging identifiers" during the process. Currently we compile an overview of the broad variety of sample types and their associated data. QR-coding of the boxes of rock samples and sediment cores is near completion, delineating their location in the repository and linking a particular sample to any information available about the object. Planning is in progress to streamline the flow from receiving new samples to their curation to sharing samples and information publically. Additionally, interface planning for linkage to GEOMAR databases Ocean

Elastic anisotropy of core samples from the Taiwan Chelungpu Fault Drilling Project (TCDP): direct 3-D measurements and weak anisotropy approximations

NASA Astrophysics Data System (ADS)

Louis, Laurent; David, Christian; Špaček, Petr; Wong, Teng-Fong; Fortin, Jérôme; Song, Sheng Rong

2012-01-01

The study of seismic anisotropy has become a powerful tool to decipher rock physics attributes in reservoirs or in complex tectonic settings. We compare direct 3-D measurements of P-wave velocity in 132 different directions on spherical rock samples to the prediction of the approximate model proposed by Louis et al. based on a tensorial approach. The data set includes measurements on dry spheres under confining pressure ranging from 5 to 200 MPa for three sandstones retrieved at a depth of 850, 1365 and 1394 metres in TCDP hole A (Taiwan Chelungpu Fault Drilling Project). As long as the P-wave velocity anisotropy is weak, we show that the predictions of the approximate model are in good agreement with the measurements. As the tensorial method is designed to work with cylindrical samples cored in three orthogonal directions, a significant gain both in the number of measurements involved and in sample preparation is achieved compared to measurements on spheres. We analysed the pressure dependence of the velocity field and show that as the confining pressure is raised the velocity increases, the anisotropy decreases but remains significant even at high pressure, and the shape of the ellipsoid representing the velocity (or elastic) fabric evolves from elongated to planar. These observations can be accounted for by considering the existence of both isotropic and anisotropic crack distributions and their evolution with applied pressure.

Comparison of Warner-Bratzler shear force values between round and square cross-section cores from cooked beef and pork Longissimus muscle.

PubMed

Silva, Douglas R G; Torres Filho, Robledo A; Cazedey, Henrique P; Fontes, Paulo R; Ramos, Alcinéia L S; Ramos, Eduardo M

2015-05-01

This study was conducted to investigate the effect of core sampling on Warner-Bratzler shear force evaluations of beef and pork loins (Longissimus thoracis et lumborum muscles) and to determine the relationship between them. Steaks of 2.54 cm from beef and pork loins were cooked and five round cross-section cores and five square cross-section cores of each steak were taken for shear force evaluation. Core sampling influenced both beef and pork shear force values with higher (P<0.05) average values and standard deviations for square cross-section cores. There was a strong and linear relationship (P<0.01) between round and square cross-section cores for beef (R(2)=0.78), pork (R(2)=0.70) and for beef+pork (R(2)=0.82) samples. These results indicate that it is feasible to use square cross-section cores in Warner-Bratzler shear force protocol as an alternative and potential method to standardize sampling for shear force measurements. Copyright © 2014 Elsevier Ltd. All rights reserved.

Telemetric measurement of body core temperature in exercising unconditioned Labrador retrievers.

PubMed

Angle, T Craig; Gillette, Robert L

2011-04-01

This project evaluated the use of an ingestible temperature sensor to measure body core temperature (Tc) in exercising dogs. Twenty-five healthy, unconditioned Labrador retrievers participated in an outdoor 3.5-km run, completed in 20 min on a level, 400-m grass track. Core temperature was measured continuously with a telemetric monitoring system before, during, and after the run. Data were successfully collected with no missing data points during the exercise. Core temperature elevated in the dogs from 38.7 ± 0.3°C at pre-exercise to 40.4 ± 0.6°C post-exercise. While rectal temperatures are still the standard of measurement, telemetric core temperature monitors may offer an easier and more comfortable means of sampling core temperature with minimal human and mechanical interference with the exercising dog.

A UAV-based active AirCore system for measurements of greenhouse gases

NASA Astrophysics Data System (ADS)

Andersen, Truls; Scheeren, Bert; Peters, Wouter; Chen, Huilin

2018-05-01

We developed and field-tested an unmanned aerial vehicle (UAV)-based active AirCore for atmospheric mole fraction measurements of CO2, CH4, and CO. The system applies an alternative way of using the AirCore technique invented by NOAA. As opposed to the conventional concept of passively sampling air using the atmospheric pressure gradient during descent, the active AirCore collects atmospheric air samples using a pump to pull the air through the tube during flight, which opens up the possibility to spatially sample atmospheric air. The active AirCore system used for this study weighs ˜ 1.1 kg. It consists of a ˜ 50 m long stainless-steel tube, a small stainless-steel tube filled with magnesium perchlorate, a KNF micropump, and a 45 µm orifice working together to form a critical flow of dried atmospheric air through the active AirCore. A cavity ring-down spectrometer (CRDS) was used to analyze the air samples on site not more than 7 min after landing for mole fraction measurements of CO2, CH4, and CO. We flew the active AirCore system on a UAV near the atmospheric measurement station at Lutjewad, located in the northwest of the city of Groningen in the Netherlands. Five consecutive flights took place over a 5 h period on the same morning, from sunrise until noon. We validated the measurements of CO2 and CH4 from the active AirCore against those from the Lutjewad station at 60 m. The results show a good agreement between the measurements from the active AirCore and the atmospheric station (N = 146; R2CO2: 0.97 and R2CH4: 0.94; and mean differences: ΔCO2: 0.18 ppm and ΔCH4: 5.13 ppb). The vertical and horizontal resolution (for CH4) at typical UAV speeds of 1.5 and 2.5 m s-1 were determined to be ±24.7 to 29.3 and ±41.2 to 48.9 m, respectively, depending on the storage time. The collapse of the nocturnal boundary layer and the buildup of the mixed layer were clearly observed with three consecutive vertical profile measurements in the early morning hours. Besides

Gains in efficiency and scientific potential of continental climate reconstruction provided by the LRC LacCore Facility, University of Minnesota

NASA Astrophysics Data System (ADS)

Noren, A.; Brady, K.; Myrbo, A.; Ito, E.

2007-12-01

Lacustrine sediment cores comprise an integral archive for the determination of continental paleoclimate, for their potentially high temporal resolution and for their ability to resolve spatial variability in climate across vast sections of the globe. Researchers studying these archives now have a large, nationally-funded, public facility dedicated to the support of their efforts. The LRC LacCore Facility, funded by NSF and the University of Minnesota, provides free or low-cost assistance to any portion of research projects, depending on the specific needs of the project. A large collection of field equipment (site survey equipment, coring devices, boats/platforms, water sampling devices) for nearly any lacustrine setting is available for rental, and Livingstone-type corers and drive rods may be purchased. LacCore staff can accompany field expeditions to operate these devices and curate samples, or provide training prior to device rental. The Facility maintains strong connections to experienced shipping agents and customs brokers, which vastly improves transport and importation of samples. In the lab, high-end instrumentation (e.g., multisensor loggers, high-resolution digital linescan cameras) provides a baseline of fundamental analyses before any sample material is consumed. LacCore staff provide support and training in lithological description, including smear-slide, XRD, and SEM analyses. The LRC botanical macrofossil reference collection is a valuable resource for both core description and detailed macrofossil analysis. Dedicated equipment and space for various subsample analyses streamlines these endeavors; subsamples for several analyses may be submitted for preparation or analysis by Facility technicians for a fee (e.g., carbon and sulfur coulometry, grain size, pollen sample preparation and analysis, charcoal, biogenic silica, LOI, freeze drying). The National Lacustrine Core Repository now curates ~9km of sediment cores from expeditions around the world

CVD graphene sheets electrochemically decorated with "core-shell" Co/CoO nanoparticles

NASA Astrophysics Data System (ADS)

Bayev, V. G.; Fedotova, J. A.; Kasiuk, J. V.; Vorobyova, S. A.; Sohor, A. A.; Komissarov, I. V.; Kovalchuk, N. G.; Prischepa, S. L.; Kargin, N. I.; Andrulevičius, M.; Przewoznik, J.; Kapusta, Cz.; Ivashkevich, O. A.; Tyutyunnikov, S. I.; Kolobylina, N. N.; Guryeva, P. V.

2018-05-01

The paper reports on the first successful fabrication of Co-graphene composites by electrochemical deposition of Co nanoparticles (NPs) on the sheets of twisted graphene. Characterization of the surface morphology and element mapping of twisted graphene decorated with Co NPs by transmission and scanning electron microscopy in combination with the energy-dispersive X-ray spectroscopy reveals the formation of isolated quasi-spherical oxidized Co NPs with the mean diameter 〈 d〉 ≈ 220 nm and core-shell structure. X-ray photoelectron spectroscopy indicates that the core of deposited NPs consists of metal Co while the shell is CoO. Composite Co-graphene samples containing core-shell NPs reveal an exchange bias field up to 160 Oe at 4 K as detected by vibrating sample magnetometry after the field cooling procedure.

CORE SHAPES AND ORIENTATIONS OF CORE-SÉRSIC GALAXIES

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

Dullo, Bililign T.; Graham, Alister W., E-mail: Bdullo@astro.swin.edu.au

2015-01-01

The inner and outer shapes and orientations of core-Sérsic galaxies may hold important clues to their formation and evolution. We have therefore measured the central and outer ellipticities and position angles for a sample of 24 core-Sérsic galaxies using archival Hubble Space Telescope (HST) images and data. By selecting galaxies with core-Sérsic break radii R{sub b} —a measure of the size of their partially depleted core—that are ≳ 0.''2, we find that the ellipticities and position angles are quite robust against HST seeing. For the bulk of the galaxies, there is a good agreement between the ellipticities and position anglesmore » at the break radii and the average outer ellipticities and position angles determined over R {sub e}/2 < R < R {sub e}, where R {sub e} is the spheroids' effective half light radius. However there are some interesting differences. We find a median ''inner'' ellipticity at R{sub b} of ε{sub med} = 0.13 ± 0.01, rounder than the median ellipticity of the ''outer'' regions ε{sub med} = 0.20 ± 0.01, which is thought to reflect the influence of the central supermassive black hole at small radii. In addition, for the first time we find a trend, albeit weak (2σ significance), such that galaxies with larger (stellar deficit-to-supermassive black hole) mass ratios—thought to be a measure of the number of major dry merger events—tend to have rounder inner and outer isophotes, suggesting a connection between the galaxy shapes and their merger histories. We show that this finding is not simply reflecting the well known result that more luminous galaxies are rounder, but it is no doubt related.« 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

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

Locations and descriptions of gravity, box, and push cores collected in San Francisco Bay between January and February, 1990 and 1991

USGS Publications Warehouse

Anima, Roberto J.; Clifton, H. Edward; Reiss, Carol; Wong, Florence L.

2005-01-01

A project to study San Francisco Bay sediments collected over 300 sediment gravity cores; six push cores, and three box cores in San Francisco Bay during the years 1990-91. The purpose of the sampling effort is to establish a database on the Holocene sediment history of the bay. The samples described and mapped are the first effort to catalog and present the data collected. Thus far the cores have been utilized in various cooperative studies with state colleges and universities, and other USGS divisions. These cores serve as a base for ongoing multidisciplinary studies. The sediment studies project has initiated subsequent coring efforts within the bay using refined coring techniques to attain deeper cores.

Uranium isotope ratios of Muonionalusta troilite and complications for the absolute age of the IVA iron meteorite core

NASA Astrophysics Data System (ADS)

Brennecka, Gregory A.; Amelin, Yuri; Kleine, Thorsten

2018-05-01

The crystallization ages of planetary crustal material (given by basaltic meteorites) and planetary cores (given by iron meteorites) provide fiducial marks for the progress of planetary formation, and thus, the absolute ages of these objects fundamentally direct our knowledge and understanding of planet formation and evolution. The lone precise absolute age of planetary core material was previously obtained on troilite inclusions from the IVA iron meteorite Muonionalusta. This previously reported Pb-Pb age of 4565.3 ± 0.1 Ma-assuming a 238U/235U =137.88-only post-dated the start of the Solar System by approximately 2-3 million years, and mandated fast cooling of planetary core material. Since an accurate Pb-Pb age requires a known 238U/235U of the sample, we have measured both 238U/235U and Pb isotopic compositions of troilite inclusions from Muonionalusta. The measured 238U/235U of the samples range from ∼137.84 to as low as ∼137.22, however based on Pb and U systematics, terrestrial contamination appears pervasive and has affected samples to various extents for Pb and U. The cause of the relative 235U excess in one sample does not appear to be from terrestrial contamination or the decay of short-lived 247Cm, but is more likely from fractionation of U isotopes during metal-silicate separation during core formation, exacerbated by the extreme U depletion in the planetary core. Due to limited Pb isotopic variation and terrestrial disturbance, no samples of this study produced useful age information; however the clear divergence from the previously assumed 238U/235U of any troilite in Muonionalusta introduces substantial uncertainty to the previously reported absolute age of the sample without knowledge of the 238U/235U of the sample. Uncertainties associated with U isotope heterogeneity do not allow for definition of a robust age of solidification and cooling for the IVA core. However, one sample of this work-paired with previous work using short

Improving tree age estimates derived from increment cores: a case study of red pine

Treesearch

Shawn Fraver; John B. Bradford; Brian J. Palik

2011-01-01

Accurate tree ages are critical to a range of forestry and ecological studies. However, ring counts from increment cores, if not corrected for the years between the root collar and coring height, can produce sizeable age errors. The magnitude of errors is influenced by both the height at which the core is extracted and the growth rate. We destructively sampled saplings...

Ultra-high-resolution paleoenvironmental records via direct laser-based analysis of lipid biomarkers in sediment core samples

PubMed Central

Wörmer, Lars; Elvert, Marcus; Fuchser, Jens; Lipp, Julius Sebastian; Buttigieg, Pier Luigi; Zabel, Matthias; Hinrichs, Kai-Uwe

2014-01-01

Marine microorganisms adapt to their habitat by structural modification of their membrane lipids. This concept is the basis of numerous molecular proxies used for paleoenvironmental reconstruction. Archaeal tetraether lipids from ubiquitous marine planktonic archaea are particularly abundant, well preserved in the sedimentary record and used in several molecular proxies. We here introduce the direct, extraction-free analysis of these compounds in intact sediment core sections using laser desorption ionization (LDI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). LDI FTICR-MS can detect the target lipids in single submillimeter-sized spots on sediment sections, equivalent to a sample mass in the nanogram range, and could thus pave the way for biomarker-based reconstruction of past environments and ecosystems at subannual to decadal resolution. We demonstrate that ratios of selected archaeal tetraethers acquired by LDI FTICR-MS are highly correlated with values obtained by conventional liquid chromatography/MS protocols. The ratio of the major archaeal lipids, caldarchaeol and crenarchaeol, analyzed in a 6.2-cm intact section of Mediterranean sapropel S1 at 250-µm resolution (∼4-y temporal resolution), provides an unprecedented view of the fine-scale patchiness of sedimentary biomarker distributions and the processes involved in proxy signal formation. Temporal variations of this lipid ratio indicate a strong influence of the ∼200-y de Vries solar cycle on reconstructed sea surface temperatures with possible amplitudes of several degrees, and suggest signal amplification by a complex interplay of ecological and environmental factors. Laser-based biomarker analysis of geological samples has the potential to revolutionize molecular stratigraphic studies of paleoenvironments. PMID:25331871

Hydro-geophysical responses to the injection of CO2 in core plugs of Berea sandstone

NASA Astrophysics Data System (ADS)

Song, I.; Park, K. G.

2017-12-01

We have built a laboratory-scale core flooding system to measure the relative permeability of a core sample and the acoustic response to the CO2 saturation degree at in situ condition of pressure and temperature down to a few kilometer depths. The system consisted of an acoustic velocity core holder (AVC model from the Core Laboratories) between upstream where CO2 and H2O were injected separately and downstream where the mixed fluids came out of a core sample. Core samples with 4 cm in diameter and 5 cm in length of Berea sandstone were in turn placed in the core holder for confining and axial pressures. The flooding operations of the multiphase fluids were conducted through the sample at 40ºC in temperature and 8 MPa in backpressure. CO2 and H2O in the physical condition were injected separately into a sample at constant rate with various ratios. The two phases were mixed during flowing through the sample. The mixed fluids out of the sample were separated again by their different densities in a chamber equipped with a level gauge of the interface. From the level change of the water in the separator, we measured the volume of water coming out of the sample for each test with a constant ratio of the injection rates. Then it was possible to calculate the saturation degree of CO2 from the difference between input volume and output volume of water. The differential pressure between upstream and downstream was directly measured to calculate the relative permeability as a function of the CO2 saturation degree. We also conducted ultrasonic measurements using piezoelectric sensors on the end plugs. An electric pulse was given to a sensor on one end of sample, and then ultrasonic waves were recorded from the other end. The various ratios of injection rate of CO2 and H2O into Berea sandstone yielded a range of 0.1-0.7 in CO2 saturation degree. The relative permeability was obtained at the condition of steady-state flow for given stages from the velocity of each phase and

Effects of core sealing methods on the preservation of pore water

USGS Publications Warehouse

Striffler, Pete; Peters, Charles A.

1993-01-01

Five general core sealing methods (using Protecore, Lexan, wax, Protecore with wax, and Protecore with Lexan) were studied over a two year period to determine their moisture retention capabilities. Results indicate that the multibarrier methods (Protecore with wax and Protecore with Lexan) and the single barrier methods (Protecore and wax) provide successful means of retaining moisture in cores. Additional testing indicated that a tight wrap of Saran is effective in: 1) protecting the outer vapor barriers from puncture, 2) containing any condensate in close proximity to where it was condensed, and 3) retarding condensation. Tests conducted to determine the moisture adsorption potential of wax and the use of applying a positive or negative pressure to Protecore packets proved inconclusive, but warrant further investigation. The importance of proper and timely handling of core samples in the field, including refrigeration and weighing of samples, can not be overstated.

Chemical stratigraphy of the Apollo 17 deep drill cores 70009-70007

NASA Technical Reports Server (NTRS)

Ehmann, W. D.; Ali, M. Z.

1977-01-01

A description is presented of an analysis of a total of 26 samples from three core segments (70009, 70008, 70007) of the Apollo 17 deep drill string. The deep drill string was taken about 700 m east of the Camelot Crater in the Taurus-Littrow region of the moon. Three core segments have been chemically characterized from the mainly coarse-grained upper portion of the deep drill string. The chemical data suggest that the entire 70007-70009 portion of the deep drill string examined was not deposited as a single unit, but was formed by several events sampling slightly different source materials which may have occurred over a relatively short period of time. According to the data from drill stem 70007, there were at least two phases of deposition. Core segment 70009 is probably derived from somewhat different source material than 70008. It seems to be a very well mixed material.

Evaluating the core microbiota in complex communities: A systematic investigation.

PubMed

Astudillo-García, Carmen; Bell, James J; Webster, Nicole S; Glasl, Bettina; Jompa, Jamaluddin; Montoya, Jose M; Taylor, Michael W

2017-04-01

The study of complex microbial communities poses unique conceptual and analytical challenges, with microbial species potentially numbering in the thousands. With transient or allochthonous microorganisms often adding to this complexity, a 'core' microbiota approach, focusing only on the stable and permanent members of the community, is becoming increasingly popular. Given the various ways of defining a core microbiota, it is prudent to examine whether the definition of the core impacts upon the results obtained. Here we used complex marine sponge microbiotas and undertook a systematic evaluation of the degree to which different factors used to define the core influenced the conclusions. Significant differences in alpha- and beta-diversity were detected using some but not all core definitions. However, findings related to host specificity and environmental quality were largely insensitive to major changes in the core microbiota definition. Furthermore, none of the applied definitions altered our perception of the ecological networks summarising interactions among bacteria within the sponges. These results suggest that, while care should still be taken in interpretation, the core microbiota approach is surprisingly robust, at least for comparing microbiotas of closely related samples. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.