Phase-encoded single-voxel magnetic resonance spectroscopy for suppressing outer volume signals at 7 Tesla.

PubMed

Li, Ningzhi; An, Li; Johnson, Christopher; Shen, Jun

2017-01-01

Due to imperfect slice profiles, unwanted signals from outside the selected voxel may significantly contaminate metabolite signals acquired using in vivo magnetic resonance spectroscopy (MRS). The use of outer volume suppression may exceed the SAR threshold, especially at high field. We propose using phase-encoding gradients after radiofrequency (RF) excitation to spatially encode unwanted signals originating from outside of the selected single voxel. Phase-encoding gradients were added to a standard single voxel point-resolved spectroscopy (PRESS) sequence which selects a 2 × 2 × 2 cm 3 voxel. Subsequent spatial Fourier transform was used to encode outer volume signals. Phantom and in vivo experiments were performed using both phase-encoded PRESS and standard PRESS at 7 Tesla. Quantification was performed using fitting software developed in-house. Both phantom and in vivo studies showed that spectra from the phase-encoded PRESS sequence were relatively immune from contamination by oil signals and have more accurate quantification results than spectra from standard PRESS spectra of the same voxel. The proposed phase-encoded single-voxel PRESS method can significantly suppress outer volume signals that may appear in the spectra of standard PRESS without increasing RF power deposition.

Double-layered ejecta craters on Mars: morphology, formation, and a comparison with the Ries ejecta blanket

NASA Astrophysics Data System (ADS)

Kenkmann, Thomas; Wulf, Gerwin; Sturm, Sebastian; Pietrek, Alexa

2015-04-01

The ejecta blankets of impact craters in volatile-rich environments often show characteristic layered ejecta morphologies. The so-called double-layer ejecta (DLE) craters are probably the most confusing crater types showing two ejecta layers with distinct morphologies. A phenomenological ejecta excavation and emplacement model for DLE craters is proposed based on a detailed case study of the Martian crater Steinheim - a textbook like, pristine DLE crater - and studies of other DLE craters [1]. The observations show that DLE craters on Mars are the result of an impact event into a rock/ice mixture that produces large amounts of shock-induced vaporization and melting of ground ice. The deposits of the ejecta curtain are wet in the distal part and dryer in composition in the proximal part. As a result, the outer ejecta layer is emplaced as medial and distal ejecta that propagate outwards in a fluid saturated debris flow mode after landing overrunning previously formed secondary craters. In contrast, the inner ejecta layer is formed by a translational slide of the proximal ejecta deposits. This slide overruns and superimposes parts of the outer ejecta layer. Basal melting of the ice components of the ejecta volumes at the transient crater rim is induced by frictional heating and the enhanced pressure at depth. The results indicate similar processes also for other planetary bodies with volatile-rich environments, such as Ganymede, Europa or the Earth. The Ries crater on Earth has a similar ejecta thickness distribution as DLE craters on Mars [2]. Here basal sliding and fluidization of the ejecta increases outward by the entrainment of locally derived Tertiary sands and clays, that are saturated with groundwater. References: [1] Wulf, G. & Kenkmann, T. (2015) Met. Planet. Sci. (in press); [2] Sturm, S., Wulf. G., Jung, D. & Kenkmann, T. (2013) Geology 41, 531-534.

Dynamic Determination of Oxygenation and Lung Compliance in Murine Pneumonectomy

PubMed Central

Gibney, Barry; Lee, Grace S.; Houdek, Jan; Lin, Miao; Miele, Lino; Chamoto, Kenji; Konerding, Moritz A.; Tsuda, Akira; Mentzer, Steven J.

2012-01-01

Thoracic surgical procedures in mice have been applied to a wide range of investigations, but little is known about the murine physiologic response to pulmonary surgery. Using continuous arterial oximetry monitoring and the FlexiVent murine ventilator, we investigated the effect of anesthesia and pneumonectomy on mouse oxygen saturation and lung mechanics. Sedation resulted in a dose-dependent decline of oxygen saturation that ranged from 55–82%. Oxygen saturation was restored by mechanical ventilation with increased rate and tidal volumes. In the mouse strain studied, optimal ventilatory rates were a rate of 200/minute and a tidal volume of 10ml/kg. Sustained inflation pressures, referred to as a "recruitment maneuver," improved lung volumes, lung compliance and arterial oxygenation. In contrast, positive end expiratory pressure (PEEP) had a detrimental effect on oxygenation; an effect that was ameliorated after pneumonectomy. Our results confirm that lung volumes in the mouse are dynamically determined and suggest a threshold level of mechanical ventilation to maintain perioperative oxygen saturation. PMID:21574875

Gas occurrence property in shales of Tuha basin northwest china

NASA Astrophysics Data System (ADS)

Chen, Jinlong; Huang, Zhilong

2017-04-01

Pore of rock under formation condition must be fulfilled by gas, oil, or water, so the volume of water and gas is equation to porous volume in shale gas. The occurrences states of gas are free gas, solution gas, and absorbed gas. Field analysis is used to obtain total gas content by improved lost gas recover method. Free gas content acquired by pore proportion of gas, which use measured pore volume minus water and oil saturation, convert gas content of standard condition by state equation. Water saturation obtain from core water content, oil saturation obtain from extract carbohydrate. Solution gas need gas solubility in oil and water to calculate solution gas content in standard condition. Absorbed gas, introduce Absorbed Gas Saturation ɛ, which acquire from isothermal adsorption volume vs field analysis gas content in many basins of published paper, need isothermal adsorption and Absorbed Gas Saturation to obtain absorbed gas content. All of the data build connect with logging value by regression equation. The gas content is 0.92-1.53 m3/t from field analysis, evaluate gas content is 1.33 m3/t average, free gas proportion is about 47%, absorbed gas counter for 49%, and solution gas is average 4%.

Dual character of Sundarban estuary as a source and sink of CO2 during summer: an investigation of spatial dynamics.

PubMed

Akhand, Anirban; Chanda, Abhra; Dutta, Sachinandan; Manna, Sudip; Sanyal, Pranabes; Hazra, Sugata; Rao, K H; Dadhwal, V K

2013-08-01

A comprehensive attempt has been made to evaluate the diurnal and spatial pattern of CO2 exchange between the atmosphere and water along the estuarine track of Indian Sundarbans during the two summer months, April and May, 2011. Rigorous field observations were carried out which included the hourly measurements of total alkalinity, pH, fugacity of CO2 in ambient air and water surface, dissolved oxygen, and chlorophyll a. The estuarine water was found rich in total alkalinity and was oversaturated with CO2 throughout the diurnal cycle in the two stations situated at the inner and middle estuary, respectively, whereas an entirely reverse situation was observed in the outer fringes. The fugacity of CO2 in water ranged from 152 to 657 μatm during the study period. The percentage of over-saturation in inner and middle estuary varied from 103 to 168 and 103 to 176 %, respectively, whereas the degree of under-saturation in the outer estuary lied between 40 and 99 %. Chlorophyll a concentrations were found higher in the outer estuary (12.3 ± 2.2 mg m(-3)) compared to the middle (6.4 ± 0.6 mg m(-3)) and inner parts (1.6 ± 0.2 mg m(-3)), followed by a similar decreasing pattern in nutrient availability from the outer to inner estuary. The sampling stations situated at the inner and middle estuary acted as a net source of 29.69 and 23.62 mg CO2 m(-2) day(-1), respectively, whereas the outer station behaved as a net sink of -33.37 mg CO2 m(-2) day(-1). The study of primary production and community respiration further supports the heterotrophic nature of the estuary in the inner region while the outer periphery was marked by dominant autotrophic character. These contrasting results are in parity with the source characters of many inner estuaries and sinking characters of the outer estuaries situated at the distal continental shelf areas.

Plasma current start-up by the outer ohmic heating coils in the Saskatchewan TORus Modified (STOR-M) iron core tokamak

DOE PAGES

Mitarai, O.; Xiao, C.; McColl, D.; ...

2015-03-24

A plasma current up to 15 kA has been driven with outer ohmic heating (OH) coils in the STOR-M iron core tokamak. Even when the inner OH coil is disconnected, the outer OH coils alone can induce the plasma current as primary windings and initial breakdown are even easier in this coil layout. Our results suggest a possibility to use an iron core in a spherical tokamak to start up the plasma current without a central solenoid. Finally, the effect of the iron core saturation on the extension of the discharge pulse length has been estimated for further experiments inmore » the STOR-M tokamak.« less

Plasma current start-up by the outer ohmic heating coils in the Saskatchewan TORus Modified (STOR-M) iron core tokamak

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

Mitarai, O.; Xiao, C.; McColl, D.

A plasma current up to 15 kA has been driven with outer ohmic heating (OH) coils in the STOR-M iron core tokamak. Even when the inner OH coil is disconnected, the outer OH coils alone can induce the plasma current as primary windings and initial breakdown are even easier in this coil layout. Our results suggest a possibility to use an iron core in a spherical tokamak to start up the plasma current without a central solenoid. Finally, the effect of the iron core saturation on the extension of the discharge pulse length has been estimated for further experiments inmore » the STOR-M tokamak.« less

Electrokinetic coupling in unsaturated porous media.

PubMed

Revil, A; Linde, N; Cerepi, A; Jougnot, D; Matthäi, S; Finsterle, S

2007-09-01

We consider a charged porous material that is saturated by two fluid phases that are immiscible and continuous on the scale of a representative elementary volume. The wetting phase for the grains is water and the nonwetting phase is assumed to be an electrically insulating viscous fluid. We use a volume-averaging approach to derive the linear constitutive equations for the electrical current density as well as the seepage velocities of the wetting and nonwetting phases on the scale of a representative elementary volume. These macroscopic constitutive equations are obtained by volume-averaging Ampère's law together with the Nernst-Planck equation and the Stokes equations. The material properties entering the macroscopic constitutive equations are explicitly described as functions of the saturation of the water phase, the electrical formation factor, and parameters that describe the capillary pressure function, the relative permeability functions, and the variation of electrical conductivity with saturation. New equations are derived for the streaming potential and electro-osmosis coupling coefficients. A primary drainage and imbibition experiment is simulated numerically to demonstrate that the relative streaming potential coupling coefficient depends not only on the water saturation, but also on the material properties of the sample, as well as the saturation history. We also compare the predicted streaming potential coupling coefficients with experimental data from four dolomite core samples. Measurements on these samples include electrical conductivity, capillary pressure, the streaming potential coupling coefficient at various levels of saturation, and the permeability at saturation of the rock samples. We found very good agreement between these experimental data and the model predictions.

Surface sampling concentration and reaction probe

DOEpatents

Van Berkel, Gary J; Elnaggar, Mariam S

2013-07-16

A method of analyzing a chemical composition of a specimen is described. The method can include providing a probe comprising an outer capillary tube and an inner capillary tube disposed co-axially within the outer capillary tube, where the inner and outer capillary tubes define a solvent capillary and a sampling capillary in fluid communication with one another at a distal end of the probe; contacting a target site on a surface of a specimen with a solvent in fluid communication with the probe; maintaining a plug volume proximate a solvent-specimen interface, wherein the plug volume is in fluid communication with the probe; draining plug sampling fluid from the plug volume through the sampling capillary; and analyzing a chemical composition of the plug sampling fluid with an analytical instrument. A system for performing the method is also described.

Surface sampling concentration and reaction probe with controller to adjust sampling position

DOEpatents

Van Berkel, Gary J.; ElNaggar, Mariam S.

2016-07-19

A method of analyzing a chemical composition of a specimen is described. The method can include providing a probe comprising an outer capillary tube and an inner capillary tube disposed co-axially within the outer capillary tube, where the inner and outer capillary tubes define a solvent capillary and a sampling capillary in fluid communication with one another at a distal end of the probe; contacting a target site on a surface of a specimen with a solvent in fluid communication with the probe; maintaining a plug volume proximate a solvent-specimen interface, wherein the plug volume is in fluid communication with the probe; draining plug sampling fluid from the plug volume through the sampling capillary; and analyzing a chemical composition of the plug sampling fluid with an analytical instrument. A system for performing the method is also described.

Submersible sodium pump

DOEpatents

Brynsvold, Glen V.; Lopez, John T.; Olich, Eugene E.; West, Calvin W.

1989-01-01

An electromagnetic submerged pump has an outer cylindrical stator with an inner cylindrical conductive core for the submerged pumping of sodium in the cylindrical interstitial volume defined between the stator and core. The cylindrical interstitial volume is typically vertically oriented, and defines an inlet at the bottom and an outlet at the top. The outer stator generates upwardly conveyed toroidal magnetic fields, which fields convey preferably from the bottom of the pump to the top of the pump liquid sodium in the cold leg of a sodium cooled nuclear reactor. The outer cylindrical stator has a vertically disposed duct surrounded by alternately stacked layers of coil units and laminates.

Submersible sodium pump

DOEpatents

Brynsvold, G.V.; Lopez, J.T.; Olich, E.E.; West, C.W.

1989-11-21

An electromagnetic submerged pump has an outer cylindrical stator with an inner cylindrical conductive core for the submerged pumping of sodium in the cylindrical interstitial volume defined between the stator and core. The cylindrical interstitial volume is typically vertically oriented, and defines an inlet at the bottom and an outlet at the top. The outer stator generates upwardly conveyed toroidal magnetic fields, which fields convey preferably from the bottom of the pump to the top of the pump liquid sodium in the cold leg of a sodium cooled nuclear reactor. The outer cylindrical stator has a vertically disposed duct surrounded by alternately stacked layers of coil units and laminates. 14 figs.

Lipid immiscibility and biophysical properties: Molecular order within and among unit cell volumes

USDA-ARS?s Scientific Manuscript database

Saturated and unsaturated fatty acids clearly have a discrete chemical structure in the solid state. In a saturated solution, the solid state and solution state are in chemical equilibrium. The lipid stearic acid packs in unit cell volumes in the liquid state as well as in the solid state. Normal...

Explosives screening on a vehicle surface

DOEpatents

Parmeter, John E.; Brusseau, Charles A.; Davis, Jerry D.; Linker, Kevin L.; Hannum, David W.

2005-02-01

A system for detecting particles on the outer surface of a vehicle has a housing capable of being placed in a test position adjacent to, but not in contact with, a portion of the outer surface of the vehicle. An elongate sealing member is fastened to the housing along a perimeter surrounding the wall, and the elongate sealing member has a contact surface facing away from the wall to contact the outer surface of the vehicle to define a test volume when the wall is in the test position. A gas flow system has at least one gas inlet extending through the wall for providing a gas stream against the surface of the vehicle within the test volume. This gas stream, which preferably is air, dislodges particles from the surface of the vehicle covered by the housing. The gas stream exits the test volume through a gas outlet and particles in the stream are detected.

Fuel injector for use in a gas turbine engine

DOEpatents

Wiebe, David J.

2012-10-09

A fuel injector in a combustor apparatus of a gas turbine engine. An outer wall of the injector defines an interior volume in which an intermediate wall is disposed. A first gap is formed between the outer wall and the intermediate wall. The intermediate wall defines an internal volume in which an inner wall is disposed. A second gap is formed between the intermediate wall and the inner wall. The second gap receives cooling fluid that cools the injector. The cooling fluid provides convective cooling to the intermediate wall as it flows within the second gap. The cooling fluid also flows through apertures in the intermediate wall into the first gap where it provides impingement cooling to the outer wall and provides convective cooling to the outer wall. The inner wall defines a passageway that delivers fuel into a liner downstream from a main combustion zone.

The impactor flux in the Pluto-Charon system

NASA Technical Reports Server (NTRS)

Weissman, Paul R.; Stern, S. Alan

1994-01-01

Current impact rates of comets on Pluto and Charon are estimated. It is shown that the dominant sources of impactors are comets from the Kuiper belt and the inner Oort cloud, each of whose perihelion distribution extends across Pluto's orbit. In contrast, long-period comets from the outer Oort cloud are a negligible source of impactors. The total predicted number of craters is not sufficient to saturate the surface areas of either Pluto of Charon over the age of the Solar System. However, heavy cratering may have occurred early in the Solar System's history during clearing of planetesimals from the outer planets' zone.

Outer scale of atmospheric turbulence

NASA Astrophysics Data System (ADS)

Lukin, Vladimir P.

2005-10-01

In the early 70's, the scientists in Italy (A.Consortini, M.Bertolotti, L.Ronchi), USA (R.Buser, Ochs, S.Clifford) and USSR (V.Pokasov, V.Lukin) almost simultaneously discovered the phenomenon of deviation from the power law and the effect of saturation for the structure phase function. During a period of 35 years we have performed successively the investigations of the effect of low-frequency spectral range of atmospheric turbulence on the optical characteristics. The influence of the turbulence models as well as a outer scale of turbulence on the characteristics of telescopes and systems of laser beam formations has been determined too.

Laboratory Experiments to Study Spherical, Iron Oxide Concretion Growth Without Solid Nuclei: Implications for Understanding Meridiani "Blueberries"

NASA Astrophysics Data System (ADS)

Ormö, J.; Souza-Egipsy, V.; Chan, M. A.; Park, A. J.; Stich, M.; Komatsu, G.

2006-03-01

Spherical hematite concretions can form without a nucleus. Self-organized zones of super-saturated solution cause spherical precipitates of amorphous iron-hydroxide. Diffusion of Fe ions towards the outer perimeter of the amorphous sphere forms a rind, which then grows inwards.

Estimation of the outer-sphere contribution to the activation volume for electron exchange reactions using the mean spherical approximation

NASA Astrophysics Data System (ADS)

Takagi, Hideo D.; Swaddle, Thomas W.

1996-01-01

The outer-sphere contribution to the volume of activation of homogeneous electron exchange reactions is estimated for selected solvents on the basis of the mean spherical approximation (MSA), and the calculated values are compared with those estimated by the Strank-Hush-Marcus (SHM) theory and with activation volumes obtained experimentally for the electron exchange reaction between tris(hexafluoroacetylacetonato)ruthenium(III) and -(II) in acetone, acetonitrile, methanol and chloroform. The MSA treatment, which recognizes the molecular nature of the solvent, does not improve significantly upon the continuous-dielectric SHM theory, which represents the experimental data adequately for the more polar solvents.

Macular Diagnostic Ability in OCT for Assessing Glaucoma in High Myopia.

PubMed

Hung, Kuo-Chi; Wu, Pei-Chang; Poon, Yi-Chieh; Chang, Hsueh-Wen; Lai, Ing-Chou; Tsai, Jen-Chia; Lin, Pei-Wen; Teng, Mei-Ching

2016-02-01

To compare the diagnostic abilities of spectral-domain optical coherence tomography (SD-OCT; Spectralis OCT) and time-domain OCT (TD-OCT; Stratus OCT). Changes in macular parameters in highly myopic eyes of glaucoma patients and highly myopic eyes of glaucoma suspects were evaluated and compared. We collected data from 72 highly myopic eyes (spherical equivalent, ≤-6.0D). Forty-one eyes had perimetric glaucoma and 31 eyes were suspected to have glaucoma (control group). All eyes underwent SD-OCT and TD-OCT imaging. Area under the receiver operating characteristic (AUROC) curve and sensitivity were examined on macular volume and thickness parameters at a fixed specificity and compared between groups. The highest TD-OCT AUROC curves were found using outer inferior sector macular thickness (AUROC curve, 0.911) and volume (AUROC curve, 0.909). The highest SD-OCT AUROC curves were found using outer inferior region thickness (AUROC curve, 0.836) and volume (AUROC curve, 0.834). The difference between the two imaging modalities was not statistically significant (thickness, p = 0.141; volume, p = 0.138). The sensitivity of TD-OCT macular outer inferior average thickness was highest and was 88.2%, with a specificity of 80.4%. The sensitivity of TD-OCT average volume measurements in this same region was 76.5%, with a specificity of 91.3%. The SD-OCT average thickness measurements also had the highest sensitivity in this region, which was 78.6%, with a specificity of 82.1%. The SD-OCT volume measurements had a sensitivity of 67.9%, with a specificity of 92.3%. Both SD-OCT and TD-OCT measurements of outer inferior macular thickness and volume can differentiate between eyes of glaucoma patients and glaucoma suspects with high myopia. These independent predictors all had good sensitivity. Based on our results, SD-OCT and TD-OCT have similar diagnostic abilities. These parameters may provide useful additional data in highly myopic eyes to complement standard glaucoma diagnosis tools.

Petrophysical evaluation of the hydrocarbon potential of the Lower Cretaceous Kharita clastics, North Qarun oil field, Western Desert, Egypt

NASA Astrophysics Data System (ADS)

Teama, Mostafa A.; Nabawy, Bassem S.

2016-09-01

Based on the available well log data of six wells chosen in the North Qarun oil field in the Western Desert of Egypt, the petrophysical evaluation for the Lower Cretaceous Kharita Formation was accomplished. The lithology of Kharita Formation was analyzed using the neutron porosity-density and the neutron porosity-gamma ray crossplots as well as the litho-saturation plot. The petrophysical parameters, include shale volume, effective porosity, water saturation and hydrocarbon pore volume, were determined and traced laterally in the studied field through the iso-parametric maps. The lithology crossplots of the studied wells show that the sandstone is the main lithology of the Kharita Formation intercalated with some calcareous shale. The cutoff values of shale volume, porosity and water saturation for the productive hydrocarbon pay zones are defined to be 40%, 10% and 50%, respectively, which were determined, based on the applied crossplots approach and their limits. The iso-parametric contour maps for the average reservoir parameters; such as net-pay thickness, average porosity, shale volume, water saturation and the hydrocarbon pore volume were illustrated. From the present study, it is found that the Kharita Formation in the North Qarun oil field has promising reservoir characteristics, particularly in the northwestern part of the study area, which is considered as a prospective area for oil accumulation.

Distortion product otoacoustic emission (2f1-f2) amplitude growth in human adults and neonates.

PubMed

Abdala, C

2000-01-01

Distortion product otoacoustic emissions (DPOAEs) are thought to be by-products of an active amplification process in the cochlea and thus serve as a metric for evaluating the integrity of this process. Because the cochlear amplifier functions in a level-dependent fashion, DPOAEs recorded as a function of stimulus level (i.e., a DPOAE growth function) may provide important information about the range and operational characteristics of the cochlear amplifier. The DPOAE growth functions recorded in human adults and neonates may provide information about the maturation of these active cochlear processes. Two experiments were conducted. Experiment I included normal-hearing adults and term-born neonates. The 2f1-f2 DPOAE growth functions were recorded for both age groups at three f2 frequencies. Experiment II was an extension of the first experiment but added a subject group of premature neonates. The results of these studies indicate that DPOAE growth functions most often show amplitude saturation and nonmonotonic growth for all age groups. However, premature neonates show monotonic growth and the absence of amplitude saturation more often than adults. Those premature neonates who do show saturation also show an elevated threshold for amplitude saturation relative to adults. In contrast, term neonates are adultlike for most measures except that they show a larger percentage of nonsaturating growth functions than adults. These results may indicate immaturity in cochlear amplifier function prior to term birth in humans. Outer hair cell function and/or efferent regulation of outer hair cell function are hypothesized sources of this immaturity, although some contribution from the immature middle ear cannot be ruled out.

DIRECT-CYCLE, BOILING-WATER NUCLEAR REACTOR

DOEpatents

Harrer, J.M.; Fromm, L.W. Jr.; Kolba, V.M.

1962-08-14

A direct-cycle boiling-water nuclear reactor is described that employs a closed vessel and a plurality of fuel assemblies, each comprising an outer tube closed at its lower end, an inner tube, fuel rods in the space between the tubes and within the inner tube. A body of water lying within the pressure vessel and outside the fuel assemblies is converted to saturated steam, which enters each fuel assembly at the top and is converted to superheated steam in the fuel assembly while it is passing therethrough first downward through the space between the inner and outer tubes of the fuel assembly and then upward through the inner tube. (AEC)

Volume change associated with formation and dissociation of hydrate in sediment

USGS Publications Warehouse

Ruppel, Carolyn D.; Lee, J.Y.; Santamarina, J. Carlos

2017-01-01

Gas hydrate formation and dissociation in sediments are accompanied by changes in the bulk volume of the sediment and can lead to changes in sediment properties, loss of integrity for boreholes, and possibly regional subsidence of the ground surface over areas where methane might be produced from gas hydrate in the future. Experiments on sand, silts, and clay subject to different effective stress and containing different saturations of hydrate formed from dissolved phase tetrahydrofuran are used to systematically investigate the impact of gas hydrate formation and dissociation on bulk sediment volume. Volume changes in low specific surface sediments (i.e., having a rigid sediment skeleton like sand) are much lower than those measured in high specific surface sediments (e.g., clay). Early hydrate formation is accompanied by contraction for all soils and most stress states in part because growing gas hydrate crystals buckle skeletal force chains. Dilation can occur at high hydrate saturations. Hydrate dissociation under drained, zero lateral strain conditions is always associated with some contraction, regardless of soil type, effective stress level, or hydrate saturation. Changes in void ratio during formation-dissociation decrease at high effective stress levels. The volumetric strain during dissociation under zero lateral strain scales with hydrate saturation and sediment compressibility. The volumetric strain during dissociation under high shear is a function of the initial volume average void ratio and the stress-dependent critical state void ratio of the sediment. Other contributions to volume reduction upon hydrate dissociation are related to segregated hydrate in lenses and nodules. For natural gas hydrates, some conditions (e.g., gas production driven by depressurization) might contribute to additional volume reduction by increasing the effective stress.

A study on the applicability of the ecosystem model on water quality prediction in urban river outer moats of Yedo Castle, Nihonbashi River

NASA Astrophysics Data System (ADS)

Kakinuma, Daiki; Tsushima, Yuki; Ohdaira, Kazunori; Yamada, Tadashi

2015-04-01

The objective of the study is to elucidate the waterside environment in the outer moats of Yedo Castle and the downstream of Nihonbashi River in Tokyo. Scince integrated sewage system has been installed in the area around the outer moats of Yedo Castle and the Nihon River basin, when rainfall exceeds more than the sewage treatment capacity, overflowed untreated wastewater is released into the moats and the river. Because the moats is a closed water body, pollutants are deposited to the bottom without outflowing. While reeking offensive odors due to the decomposition, blue-green algae outbreaks affected by the residence time and eluted nutrient causes problems. Scince the Nihonbashi River is a typical tidal river in urban area, the water pollution problems in the river is complicated. This study clarified the characteristics of the water quality in terms of dissolved oxygen saturation through on-site observations. In particular, dissolved oxygen saturation in summer, it is clarified that variations from a supersaturated state due to the variations of horizontal insolation intensity and water temperature up to hypoxic water conditions in the moats. According to previous studies on the water quality of Nihonbashi River, it is clarified that there are three types of variations of dissolved oxygen which desided by rainfall scale. The mean value of dissolved oxygen saturation of all layers has decreased by about 20% at the spring tide after dredging, then it recoveres gradually and become the value before dredging during about a year. Further more, in places where sewage inflows, it is important to developed a ecosystem medel and the applicability of the model. 9 variables including cell quota (intracellular nutrients of phytoplankton) of phosphorus and nitrogen with considerring the nitrification of ammonia nitrogen are used in the model. This model can grasp the sections (such as oxygen production by photosynthesis of phytoplankton, oxygen consumption by respiration of plankton, and bottom mud) of dissolved oxygen concentration.

Impacts of Outer Continental Shelf (OCS) development on recreation and tourism. Volume 2. Final report and case studies

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

Not Available

The final report for the project is comprised of five volumes. The volume presents the study conclusions, summarizes the methodology used (more detail is found in Volume 3), discusses four case study applications of the model, and contains profiles of coastal communities in an Appendix.

Kinetics and components of the flash photocurrent of isolated retinal rods of the larval salamander, Ambystoma tigrinum.

PubMed Central

Cobbs, W H; Pugh, E N

1987-01-01

1. Membrane currents initiated by intense, 20 microseconds flashes (photocurrents) were recorded from isolated salamander rods by combined extracellular suction electrodes and intracellular tight-seal electrodes either in current or voltage clamp mode. The magnitudes (mean +/- 2 S.E.M.) of the maximal photoresponses recorded by the suction and by the intracellular electrode respectively were 40 +/- 5 pA (n = 18) and 35 +/- 7 mV (n = 8) for current clamp at zero current; 43 +/- 9 pA and 66 +/- 13 (n = 11) pA for voltage clamp at the zero-current holding potential, -24 +/- 3 mV. 2. Photocurrents initiated by flashes isomerizing 0.1% or more of the outer segment's rhodopsin achieved a saturated velocity and were 95% complete in less than 50 ms. The effect of incrementing flash intensity above 0.1% isomerization can be described as a translation of the photocurrent along the time axis towards the origin. Within the interval 0-50 ms the latter two-thirds of the velocity-saturated photocurrent is well described as a single-exponential decay. The decay was much faster in voltage clamp (2.8 +/- 1.2 ms, n = 11) than in current clamp mode (17 +/- 5 ms, n = 17). 3. The initial third of the velocity-saturated photocurrent, occurring over the interval from the flash to the onset of exponential decay, followed about the same time course in current and voltage clamp. The time interval occupied by this initial 'latent' phase decreased with increasing flash intensity and attained an apparent minimum of about 7 ms in response to flashes isomerizing 10% or more of the rhodopsin at ca. 22 degrees C. 4. The hypothesis that the decay of outer segment light-sensitive membrane current is the same in current and voltage clamp was supported by an analysis of the difference between outer segment currents measured successively in the two recording modes. First, the tail of the difference current decayed exponentially with a time constant approximately equal to R x C, where R and C are independently estimated slope resistance and capacitance of the rod. Secondly, the integral of the difference current, when divided by outer segment capacitance, closely approximated the hyperpolarizing light response measured under current clamp. Thus, displacement current accounted for the difference between photocurrents measured in current and voltage clamp.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2832596

Calcium and magnesium fluxes across the plasma membrane of the toad rod outer segment.

PubMed Central

Nakatani, K; Yau, K W

1988-01-01

1. Membrane current was recorded from an isolated, dark-adapted toad rod by sucking either its inner segment or outer segment into a tight-fitting glass pipette containing Ringer solution. The remainder of the cell was exposed to bath solution which could be changed rapidly. 2. In normal Ringer solution the current response of a cell to a saturating flash or step of light showed a small secondary rise at its initial peak. The profile of this secondary rise (i.e. amplitude and time course) was independent of both the intensity and the duration of illumination once the light response had reached a plateau level. 3. This secondary rise disappeared when external Na+ around the outer segment was replaced by Li+ or guanidinium, suggesting that it represented an electrogenic Na+-dependent Ca2+ efflux which was declining after the onset of light. 4. This Na+-Ca2+ exchange activity showed a roughly exponential decline, with a time constant of about 0.5 s. Exponential extrapolation of the exchange current to the time at half-height of the light response gave an initial amplitude of about 2 pA. Using La3+ as a blocker, we did not detect any steady exchange current after the initial exponential decline. 5. An intense flash superposed on a just-saturating steady background light failed to produce any incremental exchange current transient. 6. Our interpretation of the above results is that in darkness there are counterbalancing levels of Ca2+ influx (through the light-sensitive conductance) and efflux (through the Na+-Ca2+ exchange) across the plasma membrane of the rod outer segment. The exchange current transient at the onset of light merely represents the unidirectional Ca2+ efflux which becomes revealed as a result of the stoppage of the Ca2+ influx, rather than a de novo Ca2+ efflux triggered by light. 7. Consistent with this interpretation, a test light delivered soon after a saturating, conditioning light elicited little exchange current, which then gradually recovered to control value with a time course parallel to the restoration of the dark current. Conversely, when the dark current was increased above its physiological level by IBMX (isobutylmethylxanthine) the exchange current transient became larger than control.(ABSTRACT TRUNCATED AT 400 WORDS) Images Fig. 8 PMID:2457685

Spinning fluids reactor

DOEpatents

Miller, Jan D; Hupka, Jan; Aranowski, Robert

2012-11-20

A spinning fluids reactor, includes a reactor body (24) having a circular cross-section and a fluid contactor screen (26) within the reactor body (24). The fluid contactor screen (26) having a plurality of apertures and a circular cross-section concentric with the reactor body (24) for a length thus forming an inner volume (28) bound by the fluid contactor screen (26) and an outer volume (30) bound by the reactor body (24) and the fluid contactor screen (26). A primary inlet (20) can be operatively connected to the reactor body (24) and can be configured to produce flow-through first spinning flow of a first fluid within the inner volume (28). A secondary inlet (22) can similarly be operatively connected to the reactor body (24) and can be configured to produce a second flow of a second fluid within the outer volume (30) which is optionally spinning.

Capillary Imbibition of Hydraulic Fracturing Fluids into Partially Saturated Shale

NASA Astrophysics Data System (ADS)

Birdsell, D.; Rajaram, H.; Lackey, G.

2015-12-01

Understanding the migration of hydraulic fracturing fluids injected into unconventional reservoirs is important to assess the risk of aquifer contamination and to optimize oil and gas production. Capillary imbibition causes fracturing fluids to flow from fractures into the rock matrix where the fluids are sequestered for geologically long periods of time. Imbibition could explain the low amount of flowback water observed in the field (5-50% of the injected volume) and reduce the chance of fracturing fluid migrating out of formation towards overlying aquifers. We present calculations of spontaneous capillary imbibition in the form of an "imbibition rate parameter" (A) based on the only known exact analytical solution for spontaneous capillary imbibition. A depends on the hydraulic and capillary properties of the reservoir rock, the initial water saturation, and the viscosities of the wetting and nonwetting fluids. Imbibed volumes can be large for a high permeability shale gas reservoir (up to 95% of the injected volume) or quite small for a low permeability shale oil reservoir (as low as 3% of the injected volume). We also present a nondimensionalization of the imbibition rate parameter, which facilitates the calculation of A and clarifies the relation of A to initial saturation, porous medium properties, and fluid properties. Over the range of initial water saturations reported for the Marcellus shale (0.05-0.6), A varies by less than factors of ~1.8 and ~3.4 for gas and oil nonwetting phases respectively. However, A decreases significantly for larger initial water saturations. A is most sensitive to the intrinsic permeability of the reservoir rock and the viscosity of the fluids.

Numerical studies of the effects of jet-induced mixing on liquid-vapor interface condensation

NASA Technical Reports Server (NTRS)

Lin, Chin-Shun

1989-01-01

Numerical solutions of jet-induced mixing in a partially full cryogenic tank are presented. An axisymmetric laminar jet is discharged from the central part of the tank bottom toward the liquid-vapor interface. Liquid is withdrawn at the same volume flow rate from the outer part of the tank. The jet is at a temperature lower than the interface, which is maintained at a certain saturation temperature. The interface is assumed to be flat and shear-free and the condensation-induced velocity is assumed to be negligibly small compared with radial interface velocity. Finite-difference method is used to solve the nondimensional form of steady state continuity, momentum, and energy equations. Calculations are conducted for jet Reynolds numbers ranging from 150 to 600 and Prandtl numbers ranging from 0.85 to 2.65. The effects of above stated parameters on the condensation Nusselt and Stanton numbers which characterize the steady-state interface condensation process are investigated. Detailed analysis to gain a better understanding of the fundamentals of fluid mixing and interface condensation is performed.

Temporal variation in leaf nitrogen partitioning of a broad-leaved evergreen tree, Quercus myrsinaefolia.

PubMed

Yasumura, Yuko; Ishida, Atsushi

2011-01-01

We examined temporal changes in the amount of nitrogenous compounds in leaves from the outer and inner parts of the crown of Quercus myrsinaefolia growing in a seasonal climate. Throughout the leaf life span, metabolic protein and Rubisco content closely correlated with total nitrogen content, while structural protein content was relatively stable after full leaf expansion. Chlorophyll content was affected by shading as well as total nitrogen content in outer leaves that were overtopped by new shoots in the second year. Outer leaves showed a large seasonal variation in photosynthetic nitrogen-use efficiency (PNUE; the light-saturated photosynthetic rate per unit leaf nitrogen content) during the first year of their life, with PNUE decreasing from the peak in summer towards winter. Outer and inner leaves both showed age-related decline in PNUE in the second year. There were no such drastic changes in leaf nitrogen partitioning that could explain seasonal and yearly variations in PNUE. Nitrogen resorption occurred in overwintering leaves in spring. Metabolic protein explained the majority of nitrogen being resorbed, whereas structural protein, which was low in degradability, contributed little to nitrogen resorption.

Guidance and navigation requirements for unmanned flyby and swingby missions to the outer planets. Volume 1: Summary report

NASA Technical Reports Server (NTRS)

1971-01-01

Unmanned spacecraft missions to the outer planets are of current interest to planetary scientists, and are being studied for the post 1970 time period. Flyby, entry and orbiter missions are all being considered using both direct and planetary swingby trajectory modes. The navigation and guidance requirements for a variety of missions to the outer planets and comets including both the three and four planet Grand Tours, are summarized.

Effect of Pedestrians on the Saturation Flow Rate of Right Turn Movements at Signalized Intersection - Case Study from Rasht City

NASA Astrophysics Data System (ADS)

Roshani, Mostafa; Bargegol, Iraj

2017-10-01

Saturation flow rate is one of the important items in the analysis of the capacity of signalized intersections that are affected by some factors. Pedestrian crossing on signalized intersection is one of the factors which influence the vehicles flow. In addition, the released researches determined that the greatest impact of pedestrian on the saturation flow occurred in the Conflict zone where the highest chance of the encounter of pedestrians and vehicles has in turning movements. The purpose of this paper is to estimate the saturation flow rate considering the effect of a pedestrian on right turn movements of the signalized intersections in Rasht city. For this goal, 6 signalized intersections with 90 cycles of reviews were selected for the estimation of saturation flow rate by the microscopic method and also 3 right turn lanes containing radius differences with 70 cycles of reviews were collected for the investigation of the pedestrians’ effects. Each phase of right turn lanes cycle was divided in the pieces of 10-second period which was totally 476 sample volumes of considered pedestrians and vehicles at that period. Only 101 samples of those were ranged as saturated conditions. Finally, using different regression models, the best relationship between pedestrian’s volume and right turning vehicles flow parameters was evaluated. The results indicate that there is a primarily linear relationship between pedestrian volume and right turning vehicles flow with R2=0.6261. According to this regression model with the increase in pedestrians, saturation flow rate will be reduced. In addition, by comparing the adjustment factor obtained in the present study and other studies, it was found that the effect of pedestrians on the right-turn movements in Rasht city is less than the rest of the world.

Water content dependence of trapped air in two soils

USGS Publications Warehouse

Stonestrom, David A.; Rubin, Jacob

1989-01-01

An improved air pycnometer method was used to examine the water content dependence of trapped-air volumes in two repacked, nonswelling soils. Trapped-air volumes were determined at a series of hydrostatic equilibrium stages which were attained during water pressure-controlled wetting and drying cycles over a range of 0 to −10 kPa for a sand and 0 to −20 kPa for a loam. Small pressure perturbations, between 0.2 and 0.6 kPa, were used in the air pycnometer method. Volumes of trapped air obtained at each hydrostatic equilibrium stage were independent of perturbation level and remained relatively constant over the time required to make repeated determinations. In contrast with most of the results obtained in previous studies, which often showed irregular relations, in this study the volume fraction of trapped air was found to be a regular, monotonically increasing (though possibly hysteretic) function of water content. For the soils studied, the function definitely exceeded zero only at water contents greater than 70% of saturation. However, during the initial drying from complete water saturation, the volume fraction of trapped air was virtually zero. Air trapping influenced the water retention curves significantly only at water contents higher than about 60% of saturation. Except at zero water pressure, however, not all of the differences between the initial and the other drying retention curves were accounted for by observed differences in trapped-air volumes. Air trapping was not required for the onset of hysteresis in the water retention relation for the cases studied, i.e., when drying-to-wetting reversals were imposed at about 27% and 40% of saturation for the sand and loam soils, respectively.

Vibration suppression using a proofmass actuator operating in stroke/force saturation

NASA Technical Reports Server (NTRS)

Lindner, D. K.; Celano, T. P.; Ide, E. N.

1991-01-01

The design of the control-loop structure for a feedback control system which contains a proofmass actuator for suppressing vibration is discussed. The loop structure is composed of inner control loops, which determine the frequency of the actuator and which are directly related to the actuator and the outer loops which add damping to the structure. When the frequency response of the actuator is matched to the stroke/force saturation curve, the actuator is most effective in the vibration suppression loops, and, since the stroke/force saturation curve is characterized by the stroke length, the mass of the proofmass, and the maximum current delivered by the motor electronics, the size of the actuator can be easily determined. The results of the loop-structure model calculations are verified by examining linear DC motors as proofmass actuators for the Mast in NASA's Control of Flexible Structures program.

Impacts of Outer Continental Shelf (OCS) development on recreation and tourism. Volume 3. Detailed methodology

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

Not Available

The final report for the project is presented in five volumes. This volume, Detailed Methodology Review, presents a discussion of the methods considered and used to estimate the impacts of Outer Continental Shelf (OCS) oil and gas development on coastal recreation in California. The purpose is to provide the Minerals Management Service with data and methods to improve their ability to analyze the socio-economic impacts of OCS development. Chapter II provides a review of previous attempts to evaluate the effects of OCS development and of oil spills on coastal recreation. The review also discusses the strengths and weaknesses of differentmore » approaches and presents the rationale for the methodology selection made. Chapter III presents a detailed discussion of the methods actually used in the study. The volume contains the bibliography for the entire study.« less

Electrochemical cell design

DOEpatents

Arntzen, John D.

1978-01-01

An electrochemical cell includes two outer electrodes and a central electrode of opposite polarity, all nested within a housing having two symmetrical halves which together form an offset configuration. The outer electrodes are nested within raised portions within the side walls of each housing half while the central electrode sealingly engages the perimetric margins of the side-wall internal surfaces. Suitable interelectrode separators and electrical insulating material electrically isolate the central electrode from the housing and the outer electrodes. The outer electrodes are electrically connected to the internal surfaces of the cell housing to provide current collection. The nested structure minimizes void volume that would otherwise be filled with gas or heavy electrolyte and also provides perimetric edge surfaces for sealing and supporting at the outer margins of frangible interelectrode separator layers.

High-voltage electrical apparatus utilizing an insulating gas of sulfur hexafluoride and helium

DOEpatents

Wootton, Roy E.

1980-01-01

High-voltage electrical apparatus includes an outer housing at low potential, an inner electrode disposed within the outer housing at high potential with respect thereto, and support means for insulatably supporting the inner electrode within the outer housing. Conducting particles contaminate the interior of the outer housing, and an insulating gas electrically insulates the inner electrode from the outer housing even in the presence of the conducting particles. The insulating gas is comprised of sulfur hexafluoride at a partial pressure of from about 2.9 to about 3.4 atmospheres absolute, and helium at a partial pressure from about 1.1 to about 11.4 atmospheres absolute. The sulfur hexafluoride comprises between 20 and 65 volume percent of the insulating gas.

Double window viewing chamber assembly

NASA Technical Reports Server (NTRS)

Keller, V. W. (Inventor); Owen, R. B. (Inventor); Elkins, B. R. (Inventor); White, W. T. (Inventor)

1986-01-01

A viewing chamber which permits observation of a sample retained therein includes a pair of double window assemblies mounted in opposed openings in the walls thereof so that a light beam can directly enter and exit from the chamber. A flexible mounting arrangement for the outer windows of the window assemblies enables the windows to be brought into proper alignment. An electrical heating arrangement prevents fogging of the outer windows whereas desiccated air in the volume between the outer and inner windows prevents fogging of the latter.

Corrosion of low alloy steel containing 0.5% chromium in supercritical CO2-saturated brine and water-saturated supercritical CO2 environments

NASA Astrophysics Data System (ADS)

Wei, Liang; Gao, Kewei; Li, Qian

2018-05-01

The corrosion behavior of P110 low-Cr alloy steel in supercritical CO2-saturated brine (aqueous phase) and water-saturated supercritical CO2 (SC CO2 phase) was investigated. The results show that P110 steel primarily suffered general corrosion in the aqueous phase, while severe localized corrosion occurred in the SC CO2 phase. The formation of corrosion product scale on P110 steel in the aqueous phase divided into three stages: formation of the initial corrosion layer containing amorphous Cr(OH)3, FeCO3 and a small amount of Fe3C; transformation of initial corrosion layer to mixed layer, which consisted of FeCO3 and a small amount of Cr(OH)3 and Fe3C; growth and dissolution of the mixed layer. Finally, only a single mixed layer covered on the steel in the aqueous phase. However, the scale formed in SC CO2 phase consisted of two layers: the inner mixed layer and the dense outer FeCO3 crystalline layer.

ESTIMATION OF FREE HYDROCARBON VOLUME FROM FLUID LEVELS IN MONITORING WELLS

EPA Science Inventory

Under the assumption of local vertical equilibrium, fluid pressure distributions specified from well fluid levels in monitoring wells may be used to predict water and hydrocarbon saturation profiles given expressions for air-water-hydrocarbon saturation-pressure relations. Verti...

A feasibility study of altered spatial distribution of losses induced by eddy currents in body composition analysis

PubMed Central

2010-01-01

Background Tomographic imaging has revealed that the body mass index does not give a reliable state of overall fitness. However, high measurement costs make the tomographic imaging unsuitable for large scale studies or repeated individual use. This paper reports an experimental investigation of a new electromagnetic method and its feasibility for assessing body composition. The method is called body electrical loss analysis (BELA). Methods The BELA method uses a high-Q parallel resonant circuit to produce a time-varying magnetic field. The Q of the resonator changes when the sample is placed in its coil. This is caused by induced eddy currents in the sample. The new idea in the BELA method is the altered spatial distribution of the electrical losses generated by these currents. The distribution of losses is varied using different excitation frequencies. The feasibility of the method was tested using simplified phantoms. Two of these phantoms were rough estimations of human torso. One had fat in the middle of its volume and saline solution in the outer shell volume. The other had reversed conductivity distributions. The phantoms were placed in the resonator and the change in the losses was measured. Five different excitation frequencies from 100 kHz to 200 kHz were used. Results The rate of loss as a function of frequency was observed to be approximately three times larger for a phantom with fat in the middle of its volume than for one with fat in its outer shell volume. Conclusions At higher frequencies the major signal contribution can be shifted toward outer shell volume. This enables probing the conductivity distribution of the subject by weighting outer structural components. The authors expect that the loss changing rate over frequency can be a potential index for body composition analysis. PMID:21047441

Geohydrology and numerical simulation of the alluvium and terrace aquifer along the Beaver-North Canadian River from the Panhandle to Canton Lake, northwestern Oklahoma

USGS Publications Warehouse

Davis, Robert E.; Christenson, Scott C.

1981-01-01

A quantitative description of the hydrologic system in alluvium and terrace deposits along the Beaver-North Canadian River in northwestern Oklahoma is needed as an aid for planning and management of the aquifer. A two-dimensional finite-difference model was used to describe the aquifer and to predict the effects of future ground-water withdrawals.The aquifer principally consists of three geologic units: Alluvium with an average thickness of 30 feet, low terrace deposits with an average thickness of 50 feet, and high terrace deposits with an average thickness of 70 feet. A thin cover of dune sand overlies much of the area and provides an excellent catchment for recharge, but is generally unsaturated.Hydraulic conductivity of the aquifer ranges from 0 to 160 feet per day and averages 59 feet per day. Specific yield is estimated to be 0.29. Recharge to the aquifer is approximately 1 inch annually. Under present conditions (1978), most discharge is the result of ground-water flow to the Beaver-North Canadian River at a rate of 36 cubic feet per second and to pumpage for public-supply, industrial, and irrigation use at a rate of 28 cubic feet per second. In 1978, the aquifer had an average saturated thickness of 31 feet and contained 4.07 million acre-feet of water.The model was used to predict future head response in the aquifer to various pumping stresses. For any one area, the pumping stress was applied until the saturated thickness for that area was less than 5 feet, at which time the pumping ceased.The results of the modeled projections show that if the aquifer is stressed from 1978 to 1993 at the 1977 pumpage rates and well distribution, the average saturated thickness will decrease 1.0 foot and the volume of water in storage will be 3.94 million acre-feet, or 97 percent of the 1978 volume. If the aquifer is stressed at this same rate until 2020, the average saturated thickness will decrease an additional 0.7 foot and the volume of water in storage will be 3.84 million acre-feet, or 94 percent of the 1978 volume.If all areas of the aquifer having a 1978 saturated thickness of 5 feet or more are stressed from 1978 to 1993 at a rate of approximately1.4 acre-feet per acre per year, the average saturated thickness will decrease by 20.9 feet and the volume of water in storage will be 1.28 million acre-feet, or 31 percent of the 1978 volume. If the aquifer is stressed at this same rate until 2020, the average saturated thickness will decrease an additional 2.2 feet and the volume of water in storage will be 980,000 acre-feet, or 24 percent of the 1978 volume.The water in the aquifer is generally of the calcium bicarbonate type and is suitable for most uses. Most of the 30 water samples analyzed contained less than 500 milligrams of dissolved solids per liter.

Table and charts of equilibrium normal-shock properties for hydrogen-helium mixtures with velocities to 70 km/sec. Volume 1: 0.95 H2-0.05 He (by volume)

NASA Technical Reports Server (NTRS)

Miller, C. G., III; Wilder, S. E.

1976-01-01

Equilibrium thermodynamic and flow properties are presented in tabulated and graphical form for moving, standing, and reflected normal shock waves into hydrogen-helium mixtures representative of postulated outer planet atmospheres. These results are presented in four volumes and the volmetric compositions of the mixtures are 0.95H2-0.05He in Volume 1, 0.90H2-0.10He in Volume 2, 0.85H2-0.15He in Volume 3, and 0.75H2-0.25He in Volume 4. Properties include pressure, temperature, density, enthalpy, speed of sound, entropy, molecular-weight ratio, isentropic exponent, velocity, and species mole fractions. Incident (moving) shock velocities are varied from 4 to 70 km/sec for a range of initial pressure of 5 N/sq m to 100 kN/sq m. Results are applicable to shock-tube flows and for determining flow conditions behind the normal portion of the bow shock about a blunt body at high velocities in postulated outer planet atmospheres. The document is a revised version of the original edition of NASA SP-3085 published in 1974.

46 CFR 42.13-15 - Definitions of terms.

Code of Federal Regulations, 2013 CFR

2013-10-01

... line of the frame in a vessel with a metal shell and to the outer surface of the hull in a vessel with... vessel with a metal shell, and is the volume of displacement to the outer surface of the hull in a vessel... between the machinery space and peak bulkheads and continuous athwartships. When this lower deck is...

46 CFR 42.13-15 - Definitions of terms.

Code of Federal Regulations, 2012 CFR

2012-10-01

... line of the frame in a vessel with a metal shell and to the outer surface of the hull in a vessel with... vessel with a metal shell, and is the volume of displacement to the outer surface of the hull in a vessel... between the machinery space and peak bulkheads and continuous athwartships. When this lower deck is...

Metallic Induction Reaction Engine.

DTIC Science & Technology

1984-12-28

FODA CLAIJ TY Figure 2: Experimental Setup 2 A EML Research Metallic Induction Reaction Engine page 3 Figure 3: Aluminum Reaction Mass Ring in Flight...reaction mass materials. Furthur analysis performed with the *] numerical model indicates that there exists a back EMF saturation effect which inhibits the...instrumentation difficulties, a detailed analysis of it’s performance has not been established. r Outer Coil Projectile- Coil Inner Coil Figure 4

Hydrocode Simulations of the Chesapeake Bay Impact

NASA Technical Reports Server (NTRS)

Collins, G. S.; Melosh, H. J.

2004-01-01

The Chesapeake Bay Impact Crater (CBIC) formed about 35 million years ago (late Eocene), in a shallow marine environment (400-600 m water depth). The crater is complex and developed in a multi-layer, rheologically-variable target that comprised 400-1000 meters of soft, water-saturated sediments overlying crystalline basement. Seismic reflection data illustrates that the Chesapeake Bay crater morphology - often described as an "inverted sombrero" - is similar to other marine-target impact craters. It consists of a approx. 1 - 1.5-km deep, highly disturbed central crater, surrounded by a shallower, less deformed basin. The inner crater has a diameter of approx. 40 km; the edge of the outer basin extends to 85-km diameter. The morphological divide between the inner and outer crater is termed the inner ring or peak ring. Little is known about the nature of the inner ring. Seismic reflection data show that the underlying basement is modestly uplifted; however, it is unclear whether the pristine surface expression of the inner ring was elevated above the floor of the outer crater.

SAGUARO: a finite-element computer program for partially saturated porous flow problems

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

Eaton, R.R.; Gartling, D.K.; Larson, D.E.

1983-06-01

SAGUARO is a finite element computer program designed to calculate two-dimensional flow of mass and energy through porous media. The media may be saturated or partially saturated. SAGUARO solves the parabolic time-dependent mass transport equation which accounts for the presence of partially saturated zones through the use of highly non-linear material characteristic curves. The energy equation accounts for the possibility of partially saturated regions by adjusting the thermal capacitances and thermal conductivities according to the volume fraction of water present in the local pores. Program capabilities, user instructions and a sample problem are presented in this manual.

75 FR 17156 - Gulf of Mexico, Outer Continental Shelf, Western Planning Area, Oil and Gas Lease Sale 215 (2010...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-05

... environmental assessment (EA) for proposed Gulf of Mexico Outer Continental Shelf (OCS) oil and gas Lease Sale... Environmental Impact Statement; Volumes I and II (Multisale EIS, OCS EIS/EA MMS 2007-018) and in the Gulf of...; Western Planning Area Sales 210, 215, and 218--Final Supplemental Environmental Impact Statement...

Ceres’ impact craters: probes of near-surface internal structure and composition

NASA Astrophysics Data System (ADS)

Bland, Michael T.; Raymond, Carol; Park, Ryan; Schenk, Paul; McCord, Tom; Reddy, Vishnu; King, Scott; Sykes, Mark; Russell, Chris

2015-11-01

Dawn Framing Camera images of Ceres have revealed the existence of a heavily cratered surface. Shape models derived from these images indicate that most (though not all) large craters are quite deep: up to 6 km for craters larger than 100 km in diameter. The retention of deep craters is not consistent with a simple differentiated internal structure consisting of an outer layer composed solely of pure water ice (covered with a rocky lag) overlying a rocky core. Here we use finite element simulations to show that, for Ceres’ relatively warm surface temperatures, the timescale required to completely flatten a crater 60-km in diameter (or greater) is less than 100 Myr, assuming a relatively pure outer ice layer (for ice grain sizes ≤ 1 cm). Preserving substantial topography requires that the viscosity of Ceres’ outer-most layer (25-50 km thick) is substantially greater than that of pure water ice. A factor of ten increase in viscosity can be achieved by assuming the layer is a 50/50 ice-rock mixture by volume; however, our simulations show that such an increase is insufficient to prevent substantial relaxation over timescales of 1 Gyr. Only particulate volume fractions greater than 50% provide an increase in viscosity sufficient to prevent large-scale, rapid relaxation. Such volume fractions suggest an outer layer composed of frozen soil/regolith (i.e., more rock than ice by volume), a very salt-rich layer, or both. Notably, while most basins appear quite deep, a few relatively shallow basins have been observed (e.g., Coniraya), suggesting that relaxation may be occurring over very long timescales (e.g., 4 Ga), that Ceres’ interior is compositionally and spatial heterogeneous, and/or that temporal evolution of the interior structure and composition has occurred. If these shallow basins are in fact the result of relaxation, it places an upper limit on the viscosity of Ceres’ outer-most interior layer, implying at least some low-viscosity material is present and likely eliminating the possibility of a purely rocky (homogeneous, low density, high porosity) interior.

Alterations of the outer retina in non-arteritic anterior ischaemic optic neuropathy detected using spectral-domain optical coherence tomography.

PubMed

Ackermann, Philipp; Brachert, Maike; Albrecht, Philipp; Ringelstein, Marius; Finis, David; Geerling, Gerd; Aktas, Orhan; Guthoff, Rainer

2017-07-01

A characteristic disease pattern may be reflected by retinal layer thickness changes in non-arteritic anterior ischaemic optic neuropathy measured using spectraldomain optical coherence tomography. Retinal layer segmentation is enabled by advanced software. In this study, retinal layer thicknesses in acute and chronic non-arteritic anterior ischaemic optic neuropathy were compared. A single-centre cross-sectional analysis was used. A total of 27 patients (20 age-matched healthy eyes) were included: 14 with acute (<7 days) and 13 patients with chronic non-arteritic anterior ischaemic optic neuropathy. Macular volume and 12° peripapillary ring optical coherence tomography scans were used. The peripapillary thicknesses of the following layers were determined by manual segmentation: retinal nerve fibres, ganglion cells + inner plexiform layer, inner nuclear layer + outer plexiform layer, outer nuclear layer + inner segments of the photoreceptors and outer segments of the photoreceptors to Bruch's membrane. Macular retinal layer thicknesses were automatically determined in volume cubes centred on the fovea. Peripapillary retinal swelling in acute nonarteritic anterior ischaemic optic neuropathy was attributable to retinal nerve fibre layer, ganglion cell layer/inner plexiform layer and outer nuclear layer/segments of the photoreceptors thickening. In chronic cases, peripapillary retinal nerve fibre layer, macular ganglion cell layer and inner plexiform layer thinning were observed. In acute non-arteritic anterior ischaemic optic neuropathy, the inner and outer peripapillary retinal layers are affected by thickness changes. In chronic cases, atrophy of the ganglion cells and their axons and dendrites is evident by inner retinal layer thinning. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

Outer Retinal Assessment Using Spectral-Domain Optical Coherence Tomography in Patients With Alzheimer's and Parkinson's Disease.

PubMed

Uchida, Atsuro; Pillai, Jagan A; Bermel, Robert; Bonner-Jackson, Aaron; Rae-Grant, Alexander; Fernandez, Hubert; Bena, James; Jones, Stephen E; Leverenz, James B; Srivastava, Sunil K; Ehlers, Justis P

2018-06-01

To investigate outer retinal parameters among patients with various chronic neurodegenerative disorders by using spectral-domain coherence tomography (OCT) in a prospective cross-sectional cohort study. A total of 132 participants were enrolled following a comprehensive diagnostic evaluation with neurologic, neuropsychology, and magnetic resonance imaging volumetric evaluations. Participants were 50 years or older, either diagnosed with Alzheimer's disease (AD) dementia, amnestic mild cognitive impairment (MCI), non-AD dementia, Parkinson's disease (PD), or age- and sex-matched controls. All participants underwent a macular cube scan for both eyes by using the Cirrus 4000 HD-OCT (Zeiss, Oberkochen, Germany). The OCT image with the best quality was selected for further analysis. Outer retinal parameters including ellipsoid zone mapping and outer nuclear layer metrics were evaluated with a novel software platform. One hundred twenty-four eyes of 124 participants with AD dementia (24 eyes), amnestic MCI (22 eyes), non-AD dementia (20 eyes), PD (22 eyes), and age- and sex-matched controls (36 eyes) were included in the analysis. Eight eyes were excluded either due to the presence of macular disease or poor quality of the OCT image. The mean ages of participants were 65.9 ± 8.9 years. The outer retinal thickness measures did not show any statistical significance between the groups. However, ellipsoid zone to retinal pigment epithelium volume correlated with cognitive testing scores in all study participants. There were no identifiable differences in the outer retinal metrics across neurodegenerative disease groups and controls. The relationship between the degree of cognitive impairment and ellipsoid zone to retinal pigment epithelium volume warrants further study.

Comparative analysis of linear motor geometries for Stirling coolers

NASA Astrophysics Data System (ADS)

R, Rajesh V.; Kuzhiveli, Biju T.

2017-12-01

Compared to rotary motor driven Stirling coolers, linear motor coolers are characterized by small volume and long life, making them more suitable for space and military applications. The motor design and operational characteristics have a direct effect on the operation of the cooler. In this perspective, ample scope exists in understanding the behavioural description of linear motor systems. In the present work, the authors compare and analyze different moving magnet linear motor geometries to finalize the most favourable one for Stirling coolers. The required axial force in the linear motors is generated by the interaction of magnetic fields of a current carrying coil and that of a permanent magnet. The compact size, commercial availability of permanent magnets and low weight requirement of the system are quite a few constraints for the design. The finite element analysis performed using Maxwell software serves as the basic tool to analyze the magnet movement, flux distribution in the air gap and the magnetic saturation levels on the core. A number of material combinations are investigated for core before finalizing the design. The effect of varying the core geometry on the flux produced in the air gap is also analyzed. The electromagnetic analysis of the motor indicates that the permanent magnet height ought to be taken in such a way that it is under the influence of electromagnetic field of current carrying coil as well as the outer core in the balanced position. This is necessary so that sufficient amount of thrust force is developed by efficient utilisation of the air gap flux density. Also, the outer core ends need to be designed to facilitate enough room for the magnet movement under the operating conditions.

Phospholipid flippase activity of the reconstituted P-glycoprotein multidrug transporter.

PubMed

Romsicki, Y; Sharom, F J

2001-06-12

The P-glycoprotein multidrug transporter acts as an ATP-powered efflux pump for a large variety of hydrophobic drugs, natural products, and peptides. The protein is proposed to interact with its substrates within the hydrophobic interior of the membrane. There is indirect evidence to suggest that P-glycoprotein can also transport, or "flip", short chain fluorescent lipids between leaflets of the membrane. In this study, we use a fluorescence quenching technique to directly show that P-glycoprotein reconstituted into proteoliposomes translocates a wide variety of NBD lipids from the outer to the inner leaflet of the bilayer. Flippase activity depended on ATP hydrolysis at the outer surface of the proteoliposome, and was inhibited by vanadate. P-Glycoprotein exhibited a broad specificity for phospholipids, and translocated phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin. Lipid derivatives that were flipped included molecules with long, short, unsaturated, and saturated acyl chains and species with the NBD group covalently linked to either acyl chains or the headgroup. The extent of lipid translocation from the outer to the inner leaflet in a 20 min period at 37 degrees C was directly estimated, and fell in the range of 0.36-1.83 nmol/mg of protein. Phospholipid flipping was inhibited in a concentration-dependent, saturable fashion by various substrates and modulators, including vinblastine, verapamil, and cyclosporin A, and the efficiency of inhibition correlated well with the affinity of binding to Pgp. Taken together, these results suggest that P-glycoprotein carries out both lipid translocation and drug transport by the same path. The transporter may be a generic flippase for hydrophobic molecules with the correct steric attributes that are present within the membrane interior.

Bubble number saturation curve and asymptotics of hypobaric and hyperbaric exposures.

PubMed

Wienke, B R

1991-12-01

Within bubble number limits of the varying permeability and reduced gradient bubble models, it is shown that a linear form of the saturation curve for hyperbaric exposures and a nearly constant decompression ratio for hypobaric exposures are simultaneously recovered from the phase volume constraint. Both limits are maintained within a single bubble number saturation curve. A bubble term, varying exponentially with inverse pressure, provides closure. Two constants describe the saturation curve, both linked to seed numbers. Limits of other decompression models are also discussed and contrasted for completeness. It is suggested that the bubble number saturation curve thus provides a consistent link between hypobaric and hyperbaric data, a link not established by earlier decompression models.

Measurement of gas diffusion coefficient in liquid-saturated porous media using magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Song, Yongchen; Hao, Min; Zhao, Yuechao; Zhang, Liang

2014-12-01

In this study, the dual-chamber pressure decay method and magnetic resonance imaging (MRI) were used to dynamically visualize the gas diffusion process in liquid-saturated porous media, and the relationship of concentration-distance for gas diffusing into liquid-saturated porous media at different times were obtained by MR images quantitative analysis. A non-iterative finite volume method was successfully applied to calculate the local gas diffusion coefficient in liquid-saturated porous media. The results agreed very well with the conventional pressure decay method, thus it demonstrates that the method was feasible of determining the local diffusion coefficient of gas in liquid-saturated porous media at different times during diffusion process.

Valsalva maneuver in obstetrics: the influence of peripheral circulatory changes on function of the pulse oximeter.

PubMed

Woods, A M; Queen, J S; Lawson, D

1991-12-01

Strenuous expulsive efforts involving sequential Valsalva maneuvers may result in maternal hypoxemia during the second stage of labor. Pulse oximetry has been used to assess oxygen saturation in laboring parturients, and this study was undertaken to evaluate the performance of the pulse oximeter (Nellcor) during the Valsalva maneuver. In both pregnant patients and nonpregnant volunteers, there were consistent interruptions in the transmission of oxygen saturation data during the Valsalva maneuver. To determine the physiologic events associated with this monitoring interruption, occlusive venous impedance plethysmographs and pulse volume amplitude recordings were obtained in volunteers performing the Valsalva maneuver. A marked decrease in pulse volume amplitude was noted, which adversely affected the oximeter's ability to distinguish physiologic arterial pulsations from background noise. Each Valsalva maneuver was associated with abrupt and transient changes in peripheral vascular volumes, thus presenting the oximeter with a rapidly changing signal for analysis that violated predetermined software criteria for pulse uniformity and caused an interruption in data transmission. The authors conclude that the Valsalva maneuver interferes with the ability of pulse oximeter technology to provide useful oxygen saturation data.

Transport of water and ions in partially water-saturated porous media. Part 1. Constitutive equations

NASA Astrophysics Data System (ADS)

Revil, A.

2017-05-01

I developed a model of cross-coupled flow in partially saturated porous media based on electrokinetic coupling including the effect of ion filtration (normal and reverse osmosis) and the multi-component nature of the pore water (wetting) phase. The model also handles diffusion and membrane polarization but is valid only for saturations above the irreducible water saturation. I start with the local Nernst-Planck and Stokes equations and I use a volume-averaging procedure to obtain the generalized Ohm, Fick, and Darcy equations with cross-coupling terms at the scale of a representative elementary volume of the porous rock. These coupling terms obey Onsager's reciprocity, which is a required condition, at the macroscale, to keep the total dissipation function of the system positive. Rather than writing the electrokinetic terms in terms of zeta potential (the double layer electrical potential on the slipping plane located in the pore water), I developed the model in terms of an effective charge density dragged by the flow of the pore water. This effective charge density is found to be strongly controlled by the permeability and the water saturation. I also developed an electrical conductivity equation including the effect of saturation on both bulk and surface conductivities, the surface conductivity being associated with electromigration in the electrical diffuse layer coating the grains. This surface conductivity depends on the CEC of the porous material.

Complex conductivity of oil-contaminated clayey soils

NASA Astrophysics Data System (ADS)

Deng, Yaping; Shi, Xiaoqing; Revil, André; Wu, Jichun; Ghorbani, A.

2018-06-01

Spectral induced polarization (SIP) is considered as a promising tool in environmental investigations. However, few works have done regarding the electrical signature of oil contamination of clayey soils upon induced polarization. Laboratory column experiments plus one sandbox experiment are conducted in this study to investigate the performances of the SIP method in oil-contaminated soils. First, a total of 12 soils are investigated to reveal the influences of water and soil properties on the saturation dependence of the complex conductivity below 100 Hz. Results show that the magnitude of the complex conductivity consistently decreases with decreasing water saturation for all soils samples. The saturation n and quadrature conductivity p exponents tend to increase slightly with increasing water salinity when using a linear conductivity model. The saturation exponent increases marginally with the cation exchange capacity (CEC) and the specific surface area (Ssp) while the quadrature conductivity exponent exhibits a relatively stronger dependence on both CEC and Ssp. For the low CEC soil samples (normally ≤10 meq/100 g), the quadrature conductivity exponent p correlates well with the saturation exponent n using the relationship p = n-1. SIP method is further applied in a sandbox experiment to estimate the saturation distribution and total volume of the oil. Results demonstrate that the SIP method has a great potential for mapping the organic contaminant plume and quantifying the oil volume.

Concept model of the formation process of humic acid-kaolin complexes deduced by trichloroethylene sorption experiments and various characterizations.

PubMed

Zhu, Xiaojing; He, Jiangtao; Su, Sihui; Zhang, Xiaoliang; Wang, Fei

2016-05-01

To explore the interactions between soil organic matter and minerals, humic acid (HA, as organic matter), kaolin (as a mineral component) and Ca(2+) (as metal ions) were used to prepare HA-kaolin and Ca-HA-kaolin complexes. These complexes were used in trichloroethylene (TCE) sorption experiments and various characterizations. Interactions between HA and kaolin during the formation of their complexes were confirmed by the obvious differences between the Qe (experimental sorbed TCE) and Qe_p (predicted sorbed TCE) values of all detected samples. The partition coefficient kd obtained for the different samples indicated that both the organic content (fom) and Ca(2+) could significantly impact the interactions. Based on experimental results and various characterizations, a concept model was developed. In the absence of Ca(2+), HA molecules first patched onto charged sites of kaolin surfaces, filling the pores. Subsequently, as the HA content increased and the first HA layer reached saturation, an outer layer of HA began to form, compressing the inner HA layer. As HA loading continued, the second layer reached saturation, such that an outer-third layer began to form, compressing the inner layers. In the presence of Ca(2+), which not only can promote kaolin self-aggregation but can also boost HA attachment to kaolin, HA molecules were first surrounded by kaolin. Subsequently, first and second layers formed (with inner layer compression) via the same process as described above in the absence of Ca(2+), except that the second layer continued to load rather than reach saturation, within the investigated conditions, because of enhanced HA aggregation caused by Ca(2+). Copyright © 2016 Elsevier Ltd. All rights reserved.

46 CFR 69.65 - Calculation of volumes.

Code of Federal Regulations, 2013 CFR

2013-10-01

... accepted naval architectural practices for the spaces concerned. (b) The volume of the hull below the upper... boundary plating, in vessels constructed of metal; and (2) To the outer surface of the shell or to the... cargo space, measurements must be taken without consideration for insulation, sparring, or ceiling...

46 CFR 69.65 - Calculation of volumes.

Code of Federal Regulations, 2014 CFR

2014-10-01

... accepted naval architectural practices for the spaces concerned. (b) The volume of the hull below the upper... boundary plating, in vessels constructed of metal; and (2) To the outer surface of the shell or to the... cargo space, measurements must be taken without consideration for insulation, sparring, or ceiling...

46 CFR 69.65 - Calculation of volumes.

Code of Federal Regulations, 2012 CFR

2012-10-01

... accepted naval architectural practices for the spaces concerned. (b) The volume of the hull below the upper... boundary plating, in vessels constructed of metal; and (2) To the outer surface of the shell or to the... cargo space, measurements must be taken without consideration for insulation, sparring, or ceiling...

Reproductive tactics of male bearded goby (Sufflogobius bibarbatus) in anoxic and hypoxic waters

NASA Astrophysics Data System (ADS)

Seivåg, Maria Larsen; Salvanes, Anne Gro Vea; Utne-Palm, Anne Christine; Kjesbu, Olav Si'gurd

2016-03-01

The bearded goby (Sufflogobius bibarbatus), a key species in the northern Benguela Upwelling Ecosystem, tolerates extremely low levels of oxygen. Yet little is known about how its reproduction is affected by these harsh living conditions. The distribution patterns of alternative reproductive tactics of male bearded goby across the continental shelf off Namibia were investigated. Histology and stereology were for the first time used to validate macroscopic maturity development by estimating volume fraction of the different stages of spermatogenesis using "Delesse principle", an approach so far for teleosts barely used in studies on testes but applied in advanced oocyte estimation. The macroscopic scale appeared suitable for the purpose, and the prevalence of territorial and sneaker tactics could therefore be documented. The sneakers had relative large testes and small seminal vesicles (SV), with the opposite being the case for the territorials. A third, numerous category with intermediate sized testes and SV was also recognized with unclear underlying tactical rationale, although regression analyses indicated similar investment in testes weight in relation to somatic weight as for the territorials. Low oxygen levels were the most important factor limiting spawning activity in territorial males. Our data suggested the existence of a spawning site on the outer shelf of the central Namibian shelf where the bottom water is hypoxic (oxygen saturation of 6.2-6.7%) while the anoxic middle shelf area (oxygen saturation of 1.7-2.9%) appeared to show too low oxygen levels for spawning to take place. Hence, significant parts of this large shelf area appear unsuited for successful reproduction of the bearded goby, in particular for nest building by the territorials.

Uniform data system standardizes technical computations and the purchasing of commercially important gases

NASA Technical Reports Server (NTRS)

Johnson, V. J.; Mc Carty, R. D.; Roder, H. M.

1970-01-01

Integrated tables of pressure, volume, and temperature for the saturated liquid, from the triple point to the critical point of the gases, have been developed. Tables include definition of saturated liquid curve. Values are presented in metric and practical units. Advantages of the new tables are discussed.

75 FR 39477 - New Standards for Domestic Mailing Services

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-09

... 2009 and FY 2010 in order to be eligible for participation. 2011 Saturation and High Density Incentive... letters and flats mailed at saturation and high density prices. This program would encourage mailers to increase the volume within two of our highest margin products and would be open to all mailers meeting the...

RISK OF UNSATURATED/SATURATED TRANSPORT AND TRANSFORMATION OF CHEMICAL CONCENTRATIONS (RUSTIC): VOLUME 1. THEORY AND CODE VERIFICATION

EPA Science Inventory

The RUSTIC program links three subordinate models--PRZM, VADOFT, and SAFTMOD--in order to predict pesticide transport and transformation through the crop root zone, the unsaturated zone, and the saturated zone to drinking water wells. PRZM is a one-dimensional finite-difference m...

Spacing of bending-induced fractures at saturation: Numerical models and approximate analytical solution

NASA Astrophysics Data System (ADS)

Schöpfer, Martin; Lehner, Florian; Grasemann, Bernhard; Kaserer, Klemens; Hinsch, Ralph

2017-04-01

John G. Ramsay's sketch of structures developed in a layer progressively folded and deformed by tangential longitudinal strain (Figure 7-65 in Folding and Fracturing of Rocks) and the associated strain pattern analysis have been reproduced in many monographs on Structural Geology and are referred to in numerous publications. Although the origin of outer-arc extension fractures is well-understood and documented in many natural examples, geomechanical factors controlling their (finite or saturation) spacing are hitherto unexplored. This study investigates the formation of bending-induced fractures during constant-curvature forced folding using Distinct Element Method (DEM) numerical modelling. The DEM model comprises a central brittle layer embedded within weaker (low modulus) elastic layers; the layer interfaces are frictionless (free slip). Folding of this three-layer system is enforced by a velocity boundary condition at the model base, while a constant overburden pressure is maintained at the model top. The models illustrate several key stages of fracture array development: (i) Prior to the onset of fracture, the neutral surface is located midway between the layer boundaries; (ii) A first set of regularly spaced fractures develops once the tensile stress in the outer-arc equals the tensile strength of the layer. Since the layer boundaries are frictionless, these bending-induced fractures propagate through the entire layer; (iii) After the appearance of the first fracture set, the rate of fracture formation decreases rapidly and so-called infill fractures develop approximately midway between two existing fractures (sequential infilling); (iv) Eventually no new fractures form, irrespective of any further increase in fold curvature (fracture saturation). Analysis of the interfacial normal stress distributions suggests that at saturation the fracture-bound blocks are subjected to a loading condition similar to three-point bending. Using classical beam theory an analytical solution is derived for the critical fracture spacing, i.e. the spacing below which the maximum tensile stress cannot reach the layer strength. The model results are consistent with an approximate analytical solution, and illustrate that the spacing of bending-induced fractures is proportional to layer thickness and a square root function of the ratio of layer tensile strength to confining pressure. Although highly idealised, models and analysis presented in this study offer an explanation for fracture saturation during folding and point towards certain key factors that may control fracture spacing in natural systems.

Speed-constrained three-axes attitude control using kinematic steering

NASA Astrophysics Data System (ADS)

Schaub, Hanspeter; Piggott, Scott

2018-06-01

Spacecraft attitude control solutions typically are torque-level algorithms that simultaneously control both the attitude and angular velocity tracking errors. In contrast, robotic control solutions are kinematic steering commands where rates are treated as the control variable, and a servo-tracking control subsystem is present to achieve the desired control rates. In this paper kinematic attitude steering controls are developed where an outer control loop establishes a desired angular response history to a tracking error, and an inner control loop tracks the commanded body angular rates. The overall stability relies on the separation principle of the inner and outer control loops which must have sufficiently different response time scales. The benefit is that the outer steering law response can be readily shaped to a desired behavior, such as limiting the approach angular velocity when a large tracking error is corrected. A Modified Rodrigues Parameters implementation is presented that smoothly saturates the speed response. A robust nonlinear body rate servo loop is developed which includes integral feedback. This approach provides a convenient modular framework that makes it simple to interchange outer and inner control loops to readily setup new control implementations. Numerical simulations illustrate the expected performance for an aggressive reorientation maneuver subject to an unknown external torque.

Proceedings: Outer Planet Probe Technology Workshop, summary volume

NASA Technical Reports Server (NTRS)

1974-01-01

A summary report and overview of the Outer Planet Probe Technology Conference are given. Summary data cover: (1) state of the art concerning mission definitions, probe requirements, systems, subsystems, and mission peculiar hardware, (2) mission and equipment trade-offs associated with Saturn/Uranus baseline configuration and the influence of Titan and Jupiter options on mission performance and costs, and (3) identification of critically required future R and D activities.

Charge Transfer in Saturation Doping of Double-Wall Carbon Nanotubes

NASA Astrophysics Data System (ADS)

Tchernatinsky, Alexander; Jayanthi, Chakram; Sumanasekera, Gamini; Wu, Shi-Yu

2004-03-01

Recent experimental evidences suggest that the outer tube of a double-wall carbon nanotube (DWCNT) may serve as a 'Faraday' cage (G. Chen, et al., Phys. Rev. Lett., 90, 257403 (2003)). In this presentation, we report the result of our systematic study of the effect of saturation doping of a (10,10) single-wall carbon nanotube, a (5,5)@(10,10) DWCNT, and a C_60@(10,10) peapod using DFT-based VASP computational package (G. Kresse and J. Hafner, Phys. Rev. B, 47, 558 (1993)). By comparing the resulting charge transfer of the above mentioned cases we shall provide the physics underlying the Faraday cage behavior of DWCNTs. Acknowledgments: This work was supported by the NSF (DMR-0112824) and the U.S.DOE (DE-FG02-00ER45832).

Variable resistance constant tension and lubrication device. [using oil-saturated leather wiper

NASA Technical Reports Server (NTRS)

Smith, H. J. (Inventor)

1974-01-01

A variable resistance device is described which includes a cylindrical housing having elongated resistance wires. A movable arm having a supporting block carried on the outer end is rotatably carried by the cylindrical housing. An arcuate steel spring member is pivotally supported by the movable arm. A leather wiper member is carried adjacent to one end of the spring steel member, and an electrically conductive surface is carried adjacent to the other end. The supporting block maintains the spring steel member in compression so that a constant pressure is applied to the conductive end of the spring steel member and the leather wiper. The leather wiper is saturated with a lubricating oil for maintaining the resistance wire clean as the movable arm is manipulated.

Imbibition of hydraulic fracturing fluids into partially saturated shale

NASA Astrophysics Data System (ADS)

Birdsell, Daniel T.; Rajaram, Harihar; Lackey, Greg

2015-08-01

Recent studies suggest that imbibition of hydraulic fracturing fluids into partially saturated shale is an important mechanism that restricts their migration, thus reducing the risk of groundwater contamination. We present computations of imbibition based on an exact semianalytical solution for spontaneous imbibition. These computations lead to quantitative estimates of an imbibition rate parameter (A) with units of LT-1/2 for shale, which is related to porous medium and fluid properties, and the initial water saturation. Our calculations suggest that significant fractions of injected fluid volumes (15-95%) can be imbibed in shale gas systems, whereas imbibition volumes in shale oil systems is much lower (3-27%). We present a nondimensionalization of A, which provides insights into the critical factors controlling imbibition, and facilitates the estimation of A based on readily measured porous medium and fluid properties. For a given set of medium and fluid properties, A varies by less than factors of ˜1.8 (gas nonwetting phase) and ˜3.4 (oil nonwetting phase) over the range of initial water saturations reported for the Marcellus shale (0.05-0.6). However, for higher initial water saturations, A decreases significantly. The intrinsic permeability of the shale and the viscosity of the fluids are the most important properties controlling the imbibition rate.

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

Wiebe, David J; Fox, Timothy A

A fuel nozzle assembly for use in a combustor apparatus of a gas turbine engine. An outer housing of the fuel nozzle assembly includes an inner volume and provides a direct structural connection between a duct structure and a fuel manifold. The duct structure defines a flow passage for combustion gases flowing within the combustor apparatus. The fuel manifold defines a fuel supply channel therein in fluid communication with a source of fuel. A fuel injector of the fuel nozzle assembly is provided in the inner volume of the outer housing and defines a fuel passage therein. The fuel passagemore » is in fluid communication with the fuel supply channel of the fuel manifold for distributing the fuel from the fuel supply channel into the flow passage of the duct structure.« less

Comparison of Chest Pain Protocols for Electrocardiography-Gated Dual-Source Cardiothoracic CT in Children and Adults: The Effect of Tube Current Saturation on Radiation Dose Reduction

PubMed Central

2018-01-01

Objective To compare radiation doses between conventional and chest pain protocols using dual-source retrospectively electrocardiography (ECG)-gated cardiothoracic computed tomography (CT) in children and adults and assess the effect of tube current saturation on radiation dose reduction. Materials and Methods This study included 104 patients (16.6 ± 7.7 years, range 5–48 years) that were divided into two groups: those with and those without tube current saturation. The estimated radiation doses of retrospectively ECG-gated spiral cardiothoracic CT were compared between conventional, uniphasic, and biphasic chest pain protocols acquired with the same imaging parameters in the same patients by using paired t tests. Dose reduction percentages, patient ages, volume CT dose index values, and tube current time products per rotation were compared between the two groups by using unpaired t tests. A p value < 0.05 was considered significant. Results The volume CT dose index values of the biphasic chest pain protocol (10.8 ± 3.9 mGy) were significantly lower than those of the conventional protocol (12.2 ± 4.7 mGy, p < 0.001) and those of the uniphasic chest pain protocol (12.9 ± 4.9 mGy, p < 0.001). The dose-saving effect of biphasic chest pain protocol was significantly less with a saturated tube current (4.5 ± 10.2%) than with unsaturated tube current method (14.8 ± 11.5%, p < 0.001). In 76 patients using 100 kVp, patient age showed no significant differences between the groups with and without tube current saturation in all protocols (p > 0.05); the groups with tube current saturation showed significantly higher volume CT dose index values (p < 0.01) and tube current time product per rotation (p < 0.001) than the groups without tube current saturation in all protocols. Conclusion The radiation dose of dual-source retrospectively ECG-gated spiral cardiothoracic CT can be reduced by approximately 15% by using the biphasic chest pain protocol instead of the conventional protocol in children and adults if radiation dose parameters are further optimized to avoid tube current saturation. PMID:29353996

Characterization of Gas-Hydrate Sediment: In Situ Evaluation of Hydrate Saturation in Pores of Pressured Sedimental Samples

NASA Astrophysics Data System (ADS)

Jin, Y.; Konno, Y.; Kida, M.; Nagao, J.

2014-12-01

Hydrate saturation of gas-hydrate bearing sediment is a key of gas production from natural gas-hydrate reservoir. Developable natural gas-hydrates by conventional gas/oil production apparatus almost exist in unconsolidated sedimental layer. Generally, hydrate saturations of sedimental samples are directly estimated by volume of gas generated from dissociation of gas hydrates in pore spaces, porosity data and volume of the sediments. Furthermore, hydrate saturation can be also assessed using velocity of P-wave through sedimental samples. Nevertheless, hydrate saturation would be changed by morphological variations (grain-coating, cementing and pore-filling model) of gas hydrates in pore spaces. Jin et al.[1,2] recently observed the O-H stretching bands of H2O molecules of methane hydrate in porous media using an attenuated total reflection IR (ATR-IR) spectra. They observed in situ hydrate formation/dissociation process in sandy samples (Tohoku Keisya number 8, grain size of ca. 110 μm). In this presentation, we present IR spectroscopy approach to in situ evaluation of hydrate saturation of pressured gas-hydrate sediments. This work was supported by funding from the Research Consortium for Methane Hydrate Resources in Japan (MH21 Research Consortium) planned by the Ministry of Economy, Trade and Industry (METI), Japan. [1] Jin, Y.; Konno, Y.; Nagao, J. Energy Fules, 2012, 26, 2242-2247. [2] Jin, Y.; Oyama, H.; Nagao, J. Jpn. J. Appl. Phys. 2009, 48, No. 108001.

USING TRACERS TO DESCRIBE NAPL HETEROGENEITY

EPA Science Inventory

Tracers are frequently used to estimate both the average travel time for water flow through the tracer swept volume and NAPL saturation. The same data can be used to develop a statistical distribution describing the hydraulic conductivity in the sept volume and a possible distri...

ICRF-Induced Changes in Floating Potential and Ion Saturation Current in the EAST Divertor

NASA Astrophysics Data System (ADS)

Perkins, Rory; Hosea, Joel; Taylor, Gary; Bertelli, Nicola; Kramer, Gerrit; Qin, Chengming; Wang, Liang; Yang, Jichan; Zhang, Xinjun

2017-10-01

Injection of waves in the ion cyclotron range of frequencies (ICRF) into a tokamak can potentially raise the plasma potential via RF rectification. Probes are affected both by changes in plasma potential and also by RF-averaging of the probe characteristic, with the latter tending to drop the floating potential. We present the effect of ICRF heating on divertor Langmuir probes in the EAST experiment. Over a scan of the outer gap, probes connected to the antennas have increases in floating potential with ICRF, but probes in between the outer-vessel strike point and flux surface tangent to the antenna have decreased floating potential. This behaviour is investigated using field-line mapping. Preliminary results show that mdiplane gas puffing can suppress the strong influence of ICRF on the probes' floating potential.

Optical oximetry of volume-oscillating vascular compartments: contributions from oscillatory blood flow

NASA Astrophysics Data System (ADS)

Kainerstorfer, Jana M.; Sassaroli, Angelo; Fantini, Sergio

2016-10-01

We present a quantitative analysis of dynamic diffuse optical measurements to obtain oxygen saturation of hemoglobin in volume oscillating compartments. We used a phasor representation of oscillatory hemodynamics at the heart rate and respiration frequency to separate the oscillations of tissue concentrations of oxyhemoglobin (O) and deoxyhemoglobin (D) into components due to blood volume (subscript V) and blood flow (subscript F): O=OV+OF, D=DV+DF. This is achieved by setting the phase angle Arg(OF)-Arg(O), which can be estimated by a hemodynamic model that we recently developed. We found this angle to be -72 deg for the cardiac pulsation at 1 Hz, and -7 deg for paced breathing at 0.1 Hz. Setting this angle, we can obtain the oxygen saturation of hemoglobin of the volume-oscillating vascular compartment, SV=|OV|/(|OV|+|DV|). We demonstrate this approach with cerebral near-infrared spectroscopy measurements on healthy volunteers at rest (n=4) and during 0.1 Hz paced breathing (n=3) with a 24-channel system. Rest data at the cardiac frequency were used to calculate the arterial saturation, S(a); over all subjects and channels, we found ==0.96±0.02. In the case of paced breathing, we found =0.66±0.14, which reflects venous-dominated hemodynamics at the respiratory frequency.

Predicting relationship between magnetostriction and applied field of magnetostrictive composites

NASA Astrophysics Data System (ADS)

Guan, Xinchun; Dong, Xufeng; Ou, Jinping

2008-03-01

Consideration of demagnetization effect, the model used to calculate the magnetostriction of single particle under the applied field is firstly built up. Then treating the magnetostriction particulate as an eigenstrain, based on Eshelby equivalent inclusion and Mori-Tanaka method, the approach to calculate average magnetostriction of the composites under any applied field as well as saturation is studied. Results calculated by the approach indicate that saturation magnetostriction of magnetostrictive composites increases with increasing of particle aspect, particle volume fraction and decreasing of Young' modulus of matrix, and the influence of applied field on magnetostriction of the composites becomes more significant with larger particle volume fraction or particle aspect.

Intracranial MRA: single volume vs. multiple thin slab 3D time-of-flight acquisition.

PubMed

Davis, W L; Warnock, S H; Harnsberger, H R; Parker, D L; Chen, C X

1993-01-01

Single volume three-dimensional (3D) time-of-flight (TOF) MR angiography is the most commonly used noninvasive method for evaluating the intracranial vasculature. The sensitivity of this technique to signal loss from flow saturation limits its utility. A recently developed multislab 3D TOF technique, MOTSA, is less affected by flow saturation and would therefore be expected to yield improved vessel visualization. To study this hypothesis, intracranial MR angiograms were obtained on 10 volunteers using three techniques: MOTSA, single volume 3D TOF using a standard 4.9 ms TE (3D TOFA), and single volume 3D TOF using a 6.8 ms TE (3D TOFB). All three sets of axial source images and maximum intensity projection (MIP) images were reviewed. Each exam was evaluated for the number of intracranial vessels visualized. A total of 502 vessel segments were studied with each technique. With use of the MIP images, 86% of selected vessels were visualized with MOTSA, 64% with 3D TOFA (TE = 4.9 ms), and 67% with TOFB (TE = 6.8 ms). Similarly, with the axial source images, 91% of selected vessels were visualized with MOTSA, 77% with 3D TOFA (TE = 4.9 ms), and 82% with 3D TOFB (TE = 6.8 ms). There is improved visualization of selected intracranial vessels in normal volunteers with MOTSA as compared with single volume 3D TOF. These improvements are believed to be primarily a result of decreased sensitivity to flow saturation seen with the MOTSA technique. No difference in overall vessel visualization was noted for the two single volume 3D TOF techniques.

Simple method for RF pulse measurement using gradient reversal.

PubMed

Landes, Vanessa L; Nayak, Krishna S

2018-05-01

To develop and evaluate a simple method for measuring the envelope of small-tip radiofrequency (RF) excitation waveforms in MRI, without extra hardware or synchronization. Gradient reversal approach to evaluate RF (GRATER) involves RF excitation with a constant gradient and reversal of that gradient during signal reception to acquire the time-reversed version of an RF envelope. An outer-volume suppression prepulse is used optionally to preselect a uniform volume. GRATER was evaluated in phantom and in vivo experiments. It was compared with the programmed waveform and the traditional pick-up coil method. In uniform phantom experiments, pick-up coil, GRATER, and outer-volume suppression + GRATER matched the programmed waveforms to less than 2.1%, less than 6.1%, and less than 2.4% normalized root mean square error, respectively, for real RF pulses with flip angle less than or equal to 30°, time-bandwidth product 2 to 8, and two to five excitation bands. For flip angles greater than 30°, GRATER measurement error increased as predicted by Bloch simulation. Fat-water phantom and in vivo experiments with outer-volume suppression + GRATER demonstrated less than 6.4% normalized root mean square error. The GRATER sequence measures small-tip RF envelopes without extra hardware or synchronization in just over two times the RF duration. The sequence may be useful in prescan calibration and for measurement and precompensation of RF amplifier nonlinearity. Magn Reson Med 79:2642-2651, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Analysis of the microcirculation after soft tissue reconstruction of the outer ear with burns in patients with severe burn injuries.

PubMed

Medved, Fabian; Medesan, Raluca; Rothenberger, Jens Martin; Schaller, Hans-Eberhard; Schoeller, Thomas; Manoli, Theodora; Weitgasser, Lennart; Naumann, Aline; Weitgasser, Laurenz

2016-07-01

Reconstruction of soft tissue defects of the ear with burns remains one of the most difficult tasks for the reconstructive surgeon. Although numerous reconstructive options are available, the results are often unpredictable and worse than expected. Besides full and split skin grafting, local random pattern flaps and pedicled flaps are frequently utilized to cover soft tissue defects of the outer auricle. Because of the difficulty and unpredictable nature of outer ear reconstruction after burn injury, a case-control study was conducted to determine the best reconstructive approach. The microcirculatory properties of different types of soft tissue reconstruction of the outer ear with burns in six severely burned Caucasian patients (three men and three women; mean age, 46 years (range, 22-70)) were compared to those in the healthy tissue of the outer ear using the O2C device (Oxygen to See; LEA Medizintechnik, Gießen, Germany). The results of this study revealed that the investigated microcirculation parameters such as the median values of blood flow (control group: 126 AU), relative amount of hemoglobin (control group: 59.5 AU), and tissue oxygen saturation (control group: 73%) are most similar to those of normal ear tissue when pedicled flaps based on the superficial temporal artery were used. These findings suggest that this type of reconstruction is superior for soft tissue reconstruction of the outer ear with burns in contrast to random pattern flaps and full skin grafts regarding the microcirculatory aspects. These findings may improve the knowledge on soft tissue viability and facilitate the exceptional and delicate process of planning the reconstruction of the auricle with burns. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Influence of georeference for saturated excess overland flow modelling using 3D volumetric soft geo-objects

NASA Astrophysics Data System (ADS)

Izham, Mohamad Yusoff; Muhamad Uznir, Ujang; Alias, Abdul Rahman; Ayob, Katimon; Wan Ruslan, Ismail

2011-04-01

Existing 2D data structures are often insufficient for analysing the dynamism of saturation excess overland flow (SEOF) within a basin. Moreover, all stream networks and soil surface structures in GIS must be preserved within appropriate projection plane fitting techniques known as georeferencing. Inclusion of 3D volumetric structure of the current soft geo-objects simulation model would offer a substantial effort towards representing 3D soft geo-objects of SEOF dynamically within a basin by visualising saturated flow and overland flow volume. This research attempts to visualise the influence of a georeference system towards the dynamism of overland flow coverage and total overland flow volume generated from the SEOF process using VSG data structure. The data structure is driven by Green-Ampt methods and the Topographic Wetness Index (TWI). VSGs are analysed by focusing on spatial object preservation techniques of the conformal-based Malaysian Rectified Skew Orthomorphic (MRSO) and the equidistant-based Cassini-Soldner projection plane under the existing geodetic Malaysian Revised Triangulation 1948 (MRT48) and the newly implemented Geocentric Datum for Malaysia (GDM2000) datum. The simulated result visualises deformation of SEOF coverage under different georeference systems via its projection planes, which delineate dissimilar computation of SEOF areas and overland flow volumes. The integration of Georeference, 3D GIS and the saturation excess mechanism provides unifying evidence towards successful landslide and flood disaster management through envisioning the streamflow generating process (mainly SEOF) in a 3D environment.

Effect of Changes in Transepithelial Transport on the Uptake of Sodium across the Outer Surface of the Frog Skin

PubMed Central

Biber, Thomas U. L.

1971-01-01

The unidirectional sodium, uptake at the outer surface of the frog skin was measured by the method described by Biber and Curran (8). With bathing solutions containing 6 mM NaCl there is a good correlation between sodium uptake and short-circuit current (SCC) measured simultaneously except that the average uptake is about 40% higher than the average SCC. The discrepancy between uptake and SCC increases approximately in proportion to an increase in sodium concentration of the bathing solutions. Amiloride inhibits the unidirectional sodium uptake by 21 and 69% at a sodium concentration of 115 and 6 mM, respectively. This indicates that amiloride acts on the entry step of sodium but additional effects cannot be excluded. The sodium, uptake is not affected by 10-4 M ouabain at a sodium concentration of 115 mM but is inhibited by 40% at a sodium concentration of 6 mM. Replacement of air by nitrogen leads to a 40% decrease of sodium uptake at a sodium concentration of 6 mM. The results support the view proposed previously (8) that the sodium uptake is made up of two components, a linear component which is, essentially, not involved in transepithelial movement of sodium and a saturating component which reflects changes in transepithelial transport. Amiloride, seems largely to affect the saturating component. PMID:5559619

Phototransduction early steps model based on Beer-Lambert optical law.

PubMed

Salido, Ezequiel M; Servalli, Leonardo N; Gomez, Juan Carlos; Verrastro, Claudio

2017-02-01

The amount of available rhodopsin on the photoreceptor outer segment and its change over time is not considered in classic models of phototransduction. Thus, those models do not take into account the absorptance variation of the outer segment under different brightness conditions. The relationship between the light absorbed by a medium and its absorptance is well described by the Beer-Lambert law. This newly proposed model implements the absorptance variation phenomenon in a set of equations that admit photons per second as input and results in active rhodopsins per second as output. This study compares the classic model of phototransduction developed by Forti et al. (1989) to this new model by using different light stimuli to measure active rhodopsin and photocurrent. The results show a linear relationship between light stimulus and active rhodopsin in the Forti model and an exponential saturation in the new model. Further, photocurrent values have shown that the new model behaves equivalently to the experimental and theoretical data as published by Forti in dark-adapted rods, but fits significantly better under light-adapted conditions. The new model successfully introduced a physics optical law to the standard model of phototransduction adding a new processing layer that had not been mathematically implemented before. In addition, it describes the physiological concept of saturation and delivers outputs in concordance to input magnitudes. Copyright © 2017 Elsevier Ltd. All rights reserved.

30 CFR 250.1203 - Gas measurement.

Code of Federal Regulations, 2011 CFR

2011-07-01

... any changes to the previously-approved measurement and/or allocation procedures. Your application... and reflect the same degree of water saturation as in the gas volume. (8) When requested by the Regional Supervisor, submit copies of gas volume statements for each requested gas meter. Show whether gas...

Multimodal airway evaluation in growing patients after rapid maxillary expansion.

PubMed

Fastuca, R; Meneghel, M; Zecca, P A; Mangano, F; Antonello, M; Nucera, R; Caprioglio, A

2015-06-01

The objective of this study was to evaluate the airway volume of growing patients combining a morphological approach using cone beam computed tomography associated with functional data obtained by polysomnography examination after rapid maxillary expansion treatment. 22 Caucasian patients (mean age 8.3±0.9 years) undergoing rapid maxillary expansion with Haas type expander banded on second deciduous upper molars were enrolled for this prospective study. Cone beam computed tomography scans and polysomnography exams were collected before placing the appliance (T0) and after 12 months (T1). Image processing with airway volume computing and analyses of oxygen saturation and apnoea/hypopnoea index were performed. Airway volume, oxygen saturation and apnea/hypopnea index underwent significant increase over time. However, no significant correlation was seen between their increases. The rapid maxillary expansion treatment induced significant increases in the total airway volume and respiratory performance. Functional respiratory parameters should be included in studies evaluating the RME treatment effects on the respiratory performance.

A numerical study of granular dam-break flow

NASA Astrophysics Data System (ADS)

Pophet, N.; Rébillout, L.; Ozeren, Y.; Altinakar, M.

2017-12-01

Accurate prediction of granular flow behavior is essential to optimize mitigation measures for hazardous natural granular flows such as landslides, debris flows and tailings-dam break flows. So far, most successful models for these types of flows focus on either pure granular flows or flows of saturated grain-fluid mixtures by employing a constant friction model or more complex rheological models. These saturated models often produce non-physical result when they are applied to simulate flows of partially saturated mixtures. Therefore, more advanced models are needed. A numerical model was developed for granular flow employing a constant friction and μ(I) rheology (Jop et al., J. Fluid Mech. 2005) coupled with a groundwater flow model for seepage flow. The granular flow is simulated by solving a mixture model using Finite Volume Method (FVM). The Volume-of-Fluid (VOF) technique is used to capture the free surface motion. The constant friction and μ(I) rheological models are incorporated in the mixture model. The seepage flow is modeled by solving Richards equation. A framework is developed to couple these two solvers in OpenFOAM. The model was validated and tested by reproducing laboratory experiments of partially and fully channelized dam-break flows of dry and initially saturated granular material. To obtain appropriate parameters for rheological models, a series of simulations with different sets of rheological parameters is performed. The simulation results obtained from constant friction and μ(I) rheological models are compared with laboratory experiments for granular free surface interface, front position and velocity field during the flows. The numerical predictions indicate that the proposed model is promising in predicting dynamics of the flow and deposition process. The proposed model may provide more reliable insight than the previous assumed saturated mixture model, when saturated and partially saturated portions of granular mixture co-exist.

Apparatus and method for maintaining an article at a temperature that is less than the temperature of the ambient air

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

Klett, James; Klett, Lynn

An apparatus for maintaining the temperature of an article at a temperature that is below the ambient air temperature includes an enclosure having an outer wall that defines an interior chamber for holding a volume of sealed air. An insert is disposed inside of the chamber and has a body that is made of a porous graphite foam material. A vacuum pump penetrates the outer wall and fluidly connects the sealed air in the interior chamber with the ambient air outside of the enclosure. The temperatures of the insert and article is maintained at temperatures that are below the ambientmore » air temperature when a volume of a liquid is wicked into the pores of the porous insert and the vacuum pump is activated to reduce the pressure of a volume of sealed air within the interior chamber to a pressure that is below the vapor pressure of the liquid.« less

Gravitational failure of sea cliffs in weakly lithified sediment

USGS Publications Warehouse

Hampton, M.A.

2002-01-01

Gravitational failure of sea cliffs eroded into weakly lithified sediment at several sites in California involves episodic stress-release fracturing and cantilevered block falls. The principal variables that influence the gravitational stability are tensional stresses generated during the release of horizontal confining stress and weakening of the sediment with increased saturation levels. Individual failures typically comprise less than a cubic meter of sediment, but large areas of a cliff face can be affected by sustained instability over a period of several days. Typically, only the outer meter or so of sediment is removed during a failure episode. In-place sediment saturation levels vary over time and space, generally being higher during the rainy season but moderate to high year-round. Laboratory direct-shear tests show that sediment cohesion decreases abruptly with increasing saturation level; the decrease is similar for all tested sediment if the cohesion is normalized by the maximum, dry-sediment cohesion. Large failures that extend over most or all of the height of the sea cliff are uncommon, but a few large wedge-shaped failures sometimes occur, as does separation of large blocks at sea cliff-gully intersections.

Comparison of surfactant lipids between pleural and pulmonary lining fluids.

PubMed

Mills, P C; Chen, Y; Hills, Y C; Hills, B A

2006-01-01

Saturated phospholipids (PCs), particularly dipalmitoylphosphatidylcholine (DPPC), predominate in surfactant lining the alveoli, although little is known about the relationship between saturated and unsaturated PCs on the outer surface of the lung, the pleura. Seven healthy cats were anesthetized and a bronchoalveolar lavage (BAL) was performed, immediately followed by a pleural lavage (PL). Lipid was extracted from lavage fluid and then analyzed for saturated, primarily dipalmitoylphosphatidylcholine (DPPC), and unsaturated PC species using high-performance liquid chromatography (HPLC) with combined fluorescence and ultraviolet detection. Dilution of epithelial lining fluid (ELF) in lavage fluids was corrected for using the urea method. The concentration of DPPC in BAL fluid (85.3+/-15.7 microg/mL) was significantly higher (P=0.021) than unsaturated PCs ( approximately 40 microg/mL). However, unsaturated PCs ( approximately 34 microg/mL), particularly stearoyl-linoleoyl-phosphatidylcholine (SLPC; 17.4+/-6.8), were significantly higher (P=0.021) than DPPC (4.3+/-1.8 microg/mL) in PL fluid. These results show that unsaturated PCs appear functionally more important in the pleural cavity, which may have implications for surfactant replenishment following pleural disease or thoracic surgery.

Water storage characteristics of several peats in situ

Treesearch

D.H. Boelter

1964-01-01

Water storage characteristics of the various horizons in a northern Minnesota bog were found to vary considerably with peat type. Surface horizons of sphagnum moss contain 0.020 g. per cc. of dry material and 95 to nearly 100% water by volume at saturation. Its total porosity consisted primarily of large pores which released 0.80 cc. of water per cc. between saturation...

The influence of surface state and saturation state on the dissolution kinetics of biogenic aragonite in seawater

USGS Publications Warehouse

Acker, James G.; Byrne, R.H.

1989-01-01

Uses several realistic partial molar volume changes (??V) for aragonite dissolution in seawater. Indicates that the molar volume change for aragonite dissolution is within the bounds -37 cm 3/mole ?????V ??? -39.5 cm3/mole. -from Authors

Effective Porosity Measurements by Wet- and Dry-type Vacuum Saturations using Process-Programmable Vacuum Saturation System

NASA Astrophysics Data System (ADS)

Lee, T. J.; Lee, K. S., , Dr; Lee, S. K.

2017-12-01

One of the most important factors in measuring effective porosity by vacuum saturation method is that the air in the pore space can be fully substituted by water during the vacuum saturation process. International Society of Rock Mechanics (ISRM) suggests vacuuming a rock sample submerged in the water, while American Society of Test and Materials (ASTM) vacuuming the sample and water separately and then pour the water to the sample. In this study, we call the former wet-type vacuum saturation (WVS) method and the latter dry-type vacuum saturation (DVS) method, and compare the effective porosity measured by the two different vacuum saturation processes. For that purpose, a vacuum saturation system has been developed, which can support both WVS and DVS by only changing the process by programming. Comparison of effective porosity has been made for a cement mortar and rock samples. As a result, DVS can substitute more void volume to water than WVS, which in turn insists that DVS can provide more exact value of effective porosity than WVS.

Graded changes in enamel component volumes resulted from a short tooth bleaching procedure.

PubMed

Ferreira, Artemisa Fernanda Moura; Perez, Flávia Maria de Moraes Ramos; Limeira Júnior, Francisco de Assis; de Moura, Mirella de Fátima Liberato; de Sousa, Frederico Barbosa

2016-05-01

To test the hypothesis that changes in enamel component volumes (mineral, organic, and water volumes, and permeability) are graded from outer to inner enamel after a short bleaching procedure. Extracted unerupted human third molars had half of their crowns bleached (single bleaching session, 3 × 15 min), and tooth shade changes in bleached parts were analyzed with a spectrophotometer. Ground sections were prepared, component volumes and permeability were quantified at histological points located at varying distances from the enamel surface (n=10 points/location), representing conditions before and after bleaching. Tooth shade changes were significant (p<0.001; 95% CI=-1/-8; power=99%), and most of the enamel layer was unaffected after bleaching, except at the outer layers. Multiple analysis of covariances revealed that most of the variance of the change in enamel composition after bleaching was explained by the combination of the set of types of component volume (in decreasing order of relevance: mineral loss, organic gain, water gain, and decrease in permeability) with the set of distances from the enamel surface (graded from the enamel surface inward) (canonical R(2)=0.97; p<0.0001; power>99%). Changes in enamel composition after a short bleaching procedure followed a gradient within component volumes (mineral loss>organic gain>water gain>decrease in permeability) and decreased from the enamel surface inward. Copyright © 2016 Elsevier Ltd. All rights reserved.

Guidance and navigation requirements for unmanned flyby and swingby missions to the outer planets. Volume 2: impulsive high thrust missions, phase A

NASA Technical Reports Server (NTRS)

1969-01-01

The impulsive, high thrust missions portion of a study on guidance and navigation requirements for unmanned flyby and swingby missions to the outer planet is presented. The proper balance between groundbased navigational capability, using the deep space network (DSN) alone, and an onboard navigational capability with and without supplemental use of DSN tracking, for unmanned missions to the outer planets of the solar system is defined. A general guidance and navigation requirements program is used to survey parametrically the characteristics associated with three types of navigation systems: (1) totally onboard, (2) totally Earth-based, and (3) a combination of these two.

Dissolution of aragonite-strontianite solid solutions in nonstoichiometric Sr (HCO3)2-Ca (HCO3)2-CO2-H2O solutions

USGS Publications Warehouse

Plummer, Niel; Busenberg, E.; Glynn, P.D.; Blum, A.E.

1992-01-01

Synthetic strontianite-aragonite solid-solution minerals were dissolved in CO2-saturated non-stoichiometric solutions of Sr(HCO3)2 and Ca(HCO3)2 at 25??C. The results show that none of the dissolution reactions reach thermodynamic equilibrium. Congruent dissolution in Ca(HCO3)2 solutions either attains or closely approaches stoichiometric saturation with respect to the dissolving solid. In Sr(HCO3)2 solutions the reactions usually become incongruent, precipitating a Sr-rich phase before reaching stoichiometric saturation. Dissolution of mechanical mixtures of solids approaches stoichiometric saturation with respect to the least stable solid in the mixture. Surface uptake from subsaturated bulk solutions was observed in the initial minutes of dissolution. This surficial phase is 0-10 atomic layers thick in Sr(HCO3)2 solutions and 0-4 layers thick in Ca(HCO3)2 solutions, and subsequently dissolves and/or recrystallizes, usually within 6 min of reaction. The initial transient surface precipitation (recrystallization) process is followed by congruent dissolution of the original solid which proceeds to stoichiometric saturation, or until the precipitation of a more stable Sr-rich solid. The compositions of secondary precipitates do not correspond to thermodynamic equilibrium or stoichiometric saturation states. X-ray photoelectron spectroscopy (XPS) measurements indicate the formation of solid solutions on surfaces of aragonite and strontianite single crystals immersed in Sr(HCO3)2 and Ca(HCO3)2 solutions, respectively. In Sr(HCO3)2 solutions, the XPS signal from the outer ~ 60 A?? on aragonite indicates a composition of 16 mol% SrCO3 after only 2 min of contact, and 14-18 mol% SrCO3 after 3 weeks of contact. The strontianite surface averages approximately 22 mol% CaCO3 after 2 min of contact with Ca(HCO3)2 solution, and is 34-39 mol% CaCO3 after 3 weeks of contact. XPS analysis suggests the surface composition is zoned with somewhat greater enrichment in the outer ~25 A?? (as much as 26 mol% SrCO3 on aragonite and 44 mol% CaCO3 on strontianite). The results indicate rapid formation of a solid-solution surface phase from subsaturated aqueous solutions. The surface phase continually adjusts in composition in response to changes in composition of the bulk fluid as net dissolution proceeds. Dissolution rates of the endmembers are greatly reduced in nonstoichiometric solutions relative to dissolution rates observed in stoichiometric solutions. All solids dissolve more slowly in solutions spiked with the least soluble component ((Sr(HCO3)2)) than in solutions spiked with the more soluble component (Ca(HCO3)2), an effect that becomes increasingly significant as stoichiometric saturation is approached. It is proposed that the formation of a non-stoichiometric surface reactive zone significantly decreases dissolution rates. ?? 1992.

Quantify fluid saturation in fractures by light transmission technique and its application

NASA Astrophysics Data System (ADS)

Ye, S.; Zhang, Y.; Wu, J.

2016-12-01

The Dense Non-Aqueous Phase Liquids (DNAPLs) migration in transparent and rough fractures with variable aperture was studied experimentally using a light transmission technique. The migration of trichloroethylene (TCE) in variable-aperture fractures (20 cm wide x 32.5 cm high) showed that a TCE blob moved downward with snap-off events in four packs with apertures from 100 μm to 1000 μm, and that the pattern presented a single and tortuous cluster with many fingers in a pack with two apertures of 100 μm and 500 μm. The variable apertures in the fractures were measured by light transmission. A light intensity-saturation (LIS) model based on light transmission was used to quantify DNAPL saturation in the fracture system. Known volumes of TCE, were added to the chamber and these amounts were compared to the results obtained by LIS model. Strong correlation existed between results obtained based on LIS model and the known volumes of T CE. Sensitivity analysis showed that the aperture was more sensitive than parameter C2 of LIS model. LIS model was also used to measure dyed TCE saturation in air sparging experiment. The results showed that the distribution and amount of TCE significantly influenced the efficient of air sparging. The method developed here give a way to quantify fluid saturation in two-phase system in fractured medium, and provide a non-destructive, non-intrusive tool to investigate changes in DNAPL architecture and flow characteristics in laboratory experiments. Keywords: light transmission, fluid saturation, fracture, variable aperture AcknowledgementsFunding for this research from NSFC Project No. 41472212.

Vapor port and groundwater sampling well

DOEpatents

Hubbell, Joel M.; Wylie, Allan H.

1996-01-01

A method and apparatus has been developed for combining groundwater monitoring wells with unsaturated-zone vapor sampling ports. The apparatus allows concurrent monitoring of both the unsaturated and the saturated zone from the same well at contaminated areas. The innovative well design allows for concurrent sampling of groundwater and volatile organic compounds (VOCs) in the vadose (unsaturated) zone from a single well, saving considerable time and money. The sample tubes are banded to the outer well casing during installation of the well casing.

Vapor port and groundwater sampling well

DOEpatents

Hubbell, J.M.; Wylie, A.H.

1996-01-09

A method and apparatus have been developed for combining groundwater monitoring wells with unsaturated-zone vapor sampling ports. The apparatus allows concurrent monitoring of both the unsaturated and the saturated zone from the same well at contaminated areas. The innovative well design allows for concurrent sampling of groundwater and volatile organic compounds (VOCs) in the vadose (unsaturated) zone from a single well, saving considerable time and money. The sample tubes are banded to the outer well casing during installation of the well casing. 10 figs.

Synthesis and properties of nickel cobalt boron nanoparticles

NASA Astrophysics Data System (ADS)

Patel, J.; Pankhurst, Q. A.; Parkin, I. P.

2005-01-01

Amorphous cobalt nickel boride nanoparticles were synthesised by chemical reduction synthesis in aqueous solution. Careful control of synthesis conditions and post reaction oxidation enabled the nanoparticles to be converted into a core-shell structure comprising of an amorphous Co-Ni-B core and an outer metal oxide sheet. These particles had interesting magnetic properties including saturation magnetisations and coercivities of the order of 80 emu/g and 170 Oe respectively, making them suitable for a potential use as an exchange-pinned magnetic material.

Magnetic field transfer device and method

DOEpatents

Wipf, S.L.

1990-02-13

A magnetic field transfer device includes a pair of oppositely wound inner coils which each include at least one winding around an inner coil axis, and an outer coil which includes at least one winding around an outer coil axis. The windings may be formed of superconductors. The axes of the two inner coils are parallel and laterally spaced from each other so that the inner coils are positioned in side-by-side relation. The outer coil is outwardly positioned from the inner coils and rotatable relative to the inner coils about a rotational axis substantially perpendicular to the inner coil axes to generate a hypothetical surface which substantially encloses the inner coils. The outer coil rotates relative to the inner coils between a first position in which the outer coil axis is substantially parallel to the inner coil axes and the outer coil augments the magnetic field formed in one of the inner coils, and a second position 180[degree] from the first position, in which the augmented magnetic field is transferred into the other inner coil and reoriented 180[degree] from the original magnetic field. The magnetic field transfer device allows a magnetic field to be transferred between volumes with negligible work being required to rotate the outer coil with respect to the inner coils. 16 figs.

Magnetic field transfer device and method

DOEpatents

Wipf, Stefan L.

1990-01-01

A magnetic field transfer device includes a pair of oppositely wound inner coils which each include at least one winding around an inner coil axis, and an outer coil which includes at least one winding around an outer coil axis. The windings may be formed of superconductors. The axes of the two inner coils are parallel and laterally spaced from each other so that the inner coils are positioned in side-by-side relation. The outer coil is outwardly positioned from the inner coils and rotatable relative to the inner coils about a rotational axis substantially perpendicular to the inner coil axes to generate a hypothetical surface which substantially encloses the inner coils. The outer coil rotates relative to the inner coils between a first position in which the outer coil axis is substantially parallel to the inner coil axes and the outer coil augments the magnetic field formed in one of the inner coils, and a second position 180.degree. from the first position, in which the augmented magnetic field is transferred into the other inner coil and reoriented 180.degree. from the original magnetic field. The magnetic field transfer device allows a magnetic field to be transferred between volumes with negligible work being required to rotate the outer coil with respect to the inner coils.

Cooking utensil with improved heat retention

DOEpatents

Potter, Thomas F.; Benson, David K.; Burch, Steven D.

1997-01-01

A cooking utensil with improved heat retention includes an inner pot received within an outer pot and separated in a closely spaced-apart relationship to form a volume or chamber therebetween. The chamber is evacuated and sealed with foil leaves at the upper edges of the inner and outer pot. The vacuum created between the inner and outer pot, along with the minimum of thermal contact between the inner and outer pot, and the reduced radiative heat transfer due to low emissivity coatings on the inner and outer pot, provide for a highly insulated cooking utensil. Any combination of a plurality of mechanisms for selectively disabling and re-enabling the insulating properties of the pot are provided within the chamber. These mechanisms may include: a hydrogen gas producing and reabsorbing device such as a metal hydride, a plurality of metal contacts which can be adjusted to bridge the gap between the inner and outer pot, and a plurality of bimetallic switches which can selectively bridge the gap between the inner and outer pot. In addition, phase change materials with superior heat retention characteristics may be provided within the cooking utensil. Further, automatic and programmable control of the cooking utensil can be provided through a microprocessor and associated hardware for controlling the vacuum disable/enable mechanisms to automatically cook and save food.

Cooking utensil with improved heat retention

DOEpatents

Potter, T.F.; Benson, D.K.; Burch, S.D.

1997-07-01

A cooking utensil with improved heat retention includes an inner pot received within an outer pot and separated in a closely spaced-apart relationship to form a volume or chamber there between. The chamber is evacuated and sealed with foil leaves at the upper edges of the inner and outer pot. The vacuum created between the inner and outer pot, along with the minimum of thermal contact between the inner and outer pot, and the reduced radiative heat transfer due to low emissivity coatings on the inner and outer pot, provide for a highly insulated cooking utensil. Any combination of a plurality of mechanisms for selectively disabling and re-enabling the insulating properties of the pot are provided within the chamber. These mechanisms may include: a hydrogen gas producing and reabsorbing device such as a metal hydride, a plurality of metal contacts which can be adjusted to bridge the gap between the inner and outer pot, and a plurality of bimetallic switches which can selectively bridge the gap between the inner and outer pot. In addition, phase change materials with superior heat retention characteristics may be provided within the cooking utensil. Further, automatic and programmable control of the cooking utensil can be provided through a microprocessor and associated hardware for controlling the vacuum disable/enable mechanisms to automatically cook and save food. 26 figs.

Transition to subcritical turbulence in a tokamak plasma

NASA Astrophysics Data System (ADS)

van Wyk, F.; Highcock, E. G.; Schekochihin, A. A.; Roach, C. M.; Field, A. R.; Dorland, W.

2016-12-01

Tokamak turbulence, driven by the ion-temperature gradient and occurring in the presence of flow shear, is investigated by means of local, ion-scale, electrostatic gyrokinetic simulations (with both kinetic ions and electrons) of the conditions in the outer core of the Mega-Ampere Spherical Tokamak (MAST). A parameter scan in the local values of the ion-temperature gradient and flow shear is performed. It is demonstrated that the experimentally observed state is near the stability threshold and that this stability threshold is nonlinear: sheared turbulence is subcritical, i.e. the system is formally stable to small perturbations, but, given a large enough initial perturbation, it transitions to a turbulent state. A scenario for such a transition is proposed and supported by numerical results: close to threshold, the nonlinear saturated state and the associated anomalous heat transport are dominated by long-lived coherent structures, which drift across the domain, have finite amplitudes, but are not volume filling; as the system is taken away from the threshold into the more unstable regime, the number of these structures increases until they overlap and a more conventional chaotic state emerges. Whereas this appears to represent a new scenario for transition to turbulence in tokamak plasmas, it is reminiscent of the behaviour of other subcritically turbulent systems, e.g. pipe flows and Keplerian magnetorotational accretion flows.

Concentric micro-nebulizer for direct sample insertion

DOEpatents

Fassel, V.A.; Rice, G.W.; Lawrence, K.E.

1984-03-06

A concentric micro-nebulizer and method for introducing liquid samples into a plasma established in a plasma torch including a first tube connected to a source of plasma gas. The concentric micro-nebulizer has inner and outer concentric tubes extending upwardly within the torch for connection to a source of nebulizer gas and to a source of liquid solvent and to a source of sample liquid. The inner tube is connected to the source of liquid solvent and to the source of sample liquid and the outer tube is connected to the source of nebulizer gas. The outer tube has an orifice positioned slightly below the plasma when it is established, with the inner and outer tubes forming an annulus therebetween with the annular spacing between the tubes at said orifice being less than about 0.05mm. The dead volume of the inner tube is less than about 5 microliters.

Concentric micro-nebulizer for direct sample insertion

DOEpatents

Fassel, Velmer A.; Rice, Gary W.; Lawrence, Kimberly E.

1986-03-11

A concentric micro-nebulizer and method for introducing liquid samples into a plasma established in a plasma torch including a first tube connected to a source of plasma gas. The concentric micro-nebulizer has inner and outer concentric tubes extending upwardly within the torch for connection to a source of nebulizer gas and to a source of liquid solvent and to a source of sample liquid. The inner tube is connected to the source of liquid solvent and to the source of sample liquid and the outer tube is connected to the source of nebulizer gas. The outer tube has an orifice positioned slightly below the plasma when it is established, with the inner and outer tubes forming an annulus therebetween with the annular spacing between the tubes at said orifice being less than about 0.05 mm. The dead volume of the inner tube is less than about 5 microliters.

Venous saturation and blood flow behavior during laser-induced photodissociation of oxyhemoglobin

NASA Astrophysics Data System (ADS)

Mamilov, S. A.; Yesman, S. S.; Asimov, M. M.; Gisbrecht, A. I.

2013-03-01

The value of relative oxyhemoglobin concentration (saturation) in arterial (SаO2) and venous blood (SvO2) plays a significant role in the oxygen exchange in tissue and is used as criterion of delivery of oxygen adequate to the needs of tissue cells. Reduction of the volume of blood flows as well as reduction of oxygen concentration in arterial blood causes hypoxia - deficit of oxygen in tissue. One of the main mechanisms of elimination of hypoxia is based on compensation of the oxygen deficit by increasing the oxygen extraction from arterial blood, which leads to reduction of oxygen in the venous blood 1. In this report two optical techniques for measurement of venous blood saturation are presented. The first one is based on the pulseoximetry with artificial mechanical modulation of the tissue volume and the second one on the spectrophotometry of human respiratory rhythm. Good correlation between the results obtained with both techniques is observed.

A reflectance model for non-contact mapping of venous oxygen saturation using a CCD camera

NASA Astrophysics Data System (ADS)

Li, Jun; Dunmire, Barbrina; Beach, Kirk W.; Leotta, Daniel F.

2013-11-01

A method of non-contact mapping of venous oxygen saturation (SvO2) is presented. A CCD camera is used to image skin tissue illuminated alternately by a red (660 nm) and an infrared (800 nm) LED light source. Low cuff pressures of 30-40 mmHg are applied to induce a venous blood volume change with negligible change in the arterial blood volume. A hybrid model combining the Beer-Lambert law and the light diffusion model is developed and used to convert the change in the light intensity to the change in skin tissue absorption coefficient. A simulation study incorporating the full light diffusion model is used to verify the hybrid model and to correct a calculation bias. SvO2 in the fingers, palm, and forearm for five volunteers are presented and compared with results in the published literature. Two-dimensional maps of venous oxygen saturation are given for the three anatomical regions.

THE STRUCTURE AND CONCENTRATION OF SOLIDS IN PHOTORECEPTOR CELLS STUDIED BY REFRACTOMETRY AND INTERFERENCE MICROSCOPY

PubMed Central

Sidman, Richard L.

1957-01-01

Fragments of freshly obtained retinas of several vertebrate species were studied by refractometry, with reference to the structure of the rods and cones. The findings allowed a reassessment of previous descriptions based mainly on fixed material. The refractometric method was used also to measure the refractice indices and to calculate the concentrations of solids and water in the various cell segments. The main quantitative data were confirmed by interference microscopy. When examined by the method of refractometry the outer segments of freshly prepared retinal rods appear homogeneous. Within a few minutes a single eccentric longitudinal fiber appears, and transverse striations may develop. These changes are attributed to imbibition of water and swelling in structures normally too small for detection by light microscopy. The central "core" of outer segments and the chromophobic disc between outer and inner segments appear to be artifacts resulting from shrinkage during dehydration. The fresh outer segments of cones, and the inner segments of rods and cones also are described and illustrated. The volumes, refractive indices, concentrations of solids, and wet and dry weights of various segments of the photoreceptor cells were tabulated. Rod outer segments of the different species vary more than 100-fold in volume and mass but all have concentrations of solids of 40 to 43 per cent. Cone outer segments contain only about 30 per cent solids. The myoids, paraboloids, and ellipsoids of the inner segments likewise have characteristic refractive indices and concentrations of solids. Some of the limitations and particular virtues of refractometry as a method for quantitative analysis of living cells are discussed in comparison with more conventional biochemical techniques. Also the shapes and refractive indices of the various segments of photoreceptor cells are considered in relation to the absorption and transmission of light. The Stiles-Crawford effect can be accounted for on the basis of the structure of cone cells. PMID:13416308

Liquid balance monitoring inside conventional, Retrofit, and bio-reactor landfill cells.

PubMed

Abichou, Tarek; Barlaz, Morton A; Green, Roger; Hater, Gary

2013-10-01

The Outer Loop landfill bioreactor (OLLB) in Louisville, KY, USA has been the site of a study to evaluate long-term bioreactor performance at a full-scale operational landfill. Three types of landfill units were studied including a conventional landfill (Control cell), a new landfill area that had an air addition and recirculation piping network installed as waste was being placed (As-Built cell), and a conventional landfill that was modified to allow for liquids recirculation (Retrofit cell). During the monitoring period, the Retrofit, Control, and As-Built cells received 48, 14, and 213LMg(-1) (liters of liquids per metric ton of waste), respectively. The leachate collection system yielded 60, 57 and 198LMg(-1) from the Retrofit, Control, and As-Built cells, respectively. The head on liner in all cells was below regulatory limits. In the Control and As-Built cells, leachate head on liner decreased once waste placement stopped. The measured moisture content of the waste samples was consistent with that calculated from the estimate of accumulated liquid by the liquid balance. Additionally, measurements on excavated solid waste samples revealed large spatial variability in waste moisture content. The degree of saturation in the Control cells decreased from 85% to 75%. The degree of saturation increased from 82% to 83% due to liquids addition in the Retrofit cells and decreased back to 80% once liquid addition stopped. In the As-Built cells, the degree of saturation increased from 87% to 97% during filling activities and then started to decrease soon after filling activities stopped to reach 92% at the end of the monitoring period. The measured leachate generation rates were used to estimate an in-place saturated hydraulic conductivity of the MSW in the range of 10(-8) to 10(-7)ms(-1) which is lower than previous reports. In the Control and Retrofit cells, the net loss in liquids, 43 and 12LMg(-1), respectively, was similar to the measured settlement of 15% and 5-8% strain, respectively (Abichou et al., 2013). The increase in net liquid volume in the As-Built cells indicates that the 37% (average) measured settlement strain in these cells cannot be due to consolidation as the waste mass did not lose any moisture but rather suggests that settlement was attributable to lubrication of waste particle contacts, softening of flexible porous materials, and additional biological degradation. Copyright © 2013 Elsevier Ltd. All rights reserved.

PROMIS series. Volume 8: Midlatitude ground magnetograms

NASA Technical Reports Server (NTRS)

Fairfield, D. H.; Russell, C. T.

1990-01-01

This is the eighth in a series of volumes pertaining to the Polar Region Outer Magnetosphere International Study (PROMIS). This volume contains 24 hour stack plots of 1-minute average, H and D component, ground magnetograms for the period March 10 through June 16, 1986. Nine midlatitude ground stations were selected from the UCLA magnetogram data base that was constructed from all available digitized magnetogram stations. The primary purpose of this publication is to allow users to define universal times and onset longitudes of magnetospheric substorms.

Ring faults and ring dikes around the Orientale basin on the Moon.

PubMed

Andrews-Hanna, Jeffrey C; Head, James W; Johnson, Brandon; Keane, James T; Kiefer, Walter S; McGovern, Patrick J; Neumann, Gregory A; Wieczorek, Mark A; Zuber, Maria T

2018-08-01

The Orientale basin is the youngest and best-preserved multiring impact basin on the Moon, having experienced only modest modification by subsequent impacts and volcanism. Orientale is often treated as the type example of a multiring basin, with three prominent rings outside of the inner depression: the Inner Rook Montes, the Outer Rook Montes, and the Cordillera. Here we use gravity data from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission to reveal the subsurface structure of Orientale and its ring system. Gradients of the gravity data reveal a continuous ring dike intruded into the Outer Rook along the plane of the fault associated with the ring scarp. The volume of this ring dike is ~18 times greater than the volume of all extrusive mare deposits associated with the basin. The gravity gradient signature of the Cordillera ring indicates an offset along the fault across a shallow density interface, interpreted to be the base of the low-density ejecta blanket. Both gravity gradients and crustal thickness models indicate that the edge of the central cavity is shifted inward relative to the equivalent Inner Rook ring at the surface. Models of the deep basin structure show inflections along the crust-mantle interface at both the Outer Rook and Cordillera rings, indicating that the basin ring faults extend from the surface to at least the base of the crust. Fault dips range from 13-22° for the Cordillera fault in the northeastern quadrant, to 90° for the Outer Rook in the northwestern quadrant. The fault dips for both outer rings are lowest in the northeast, possibly due to the effects of either the direction of projectile motion or regional gradients in pre-impact crustal thickness. Similar ring dikes and ring faults are observed around the majority of lunar basins.

A Cylindrical, Inner Volume Selecting 2D-T2-Prep Improves GRAPPA-Accelerated Image Quality in MRA of the Right Coronary Artery

PubMed Central

Coristine, Andrew J.; Yerly, Jerome; Stuber, Matthias

2016-01-01

Background Two-dimensional (2D) spatially selective radiofrequency (RF) pulses may be used to excite restricted volumes. By incorporating a "pencil beam" 2D pulse into a T2-Prep, one may create a "2D-T2-Prep" that combines T2-weighting with an intrinsic outer volume suppression. This may particularly benefit parallel imaging techniques, where artefacts typically originate from residual foldover signal. By suppressing foldover signal with a 2D-T2-Prep, image quality may therefore improve. We present numerical simulations, phantom and in vivo validations to address this hypothesis. Methods A 2D-T2-Prep and a conventional T2-Prep were used with GRAPPA-accelerated MRI (R = 1.6). The techniques were first compared in numerical phantoms, where per pixel maps of SNR (SNRmulti), noise, and g-factor were predicted for idealized sequences. Physical phantoms, with compartments doped to mimic blood, myocardium, fat, and coronary vasculature, were scanned with both T2-Preparation techniques to determine the actual SNRmulti and vessel sharpness. For in vivo experiments, the right coronary artery (RCA) was imaged in 10 healthy adults, using accelerations of R = 1,3, and 6, and vessel sharpness was measured for each. Results In both simulations and phantom experiments, the 2D-T2-Prep improved SNR relative to the conventional T2-Prep, by an amount that depended on both the acceleration factor and the degree of outer volume suppression. For in vivo images of the RCA, vessel sharpness improved most at higher acceleration factors, demonstrating that the 2D-T2-Prep especially benefits accelerated coronary MRA. Conclusion Suppressing outer volume signal with a 2D-T2-Prep improves image quality particularly well in GRAPPA-accelerated acquisitions in simulations, phantoms, and volunteers, demonstrating that it should be considered when performing accelerated coronary MRA. PMID:27736866

Numerical investigation of saturated upward flow boiling of water in a vertical tube using VOF model: effect of different boundary conditions

NASA Astrophysics Data System (ADS)

Hasanpour, B.; Irandoost, M. S.; Hassani, M.; Kouhikamali, R.

2018-01-01

In this paper a numerical simulation of upward two-phase flow evaporation in a vertical tube has been studied by considering water as working fluid. To this end, the computational fluid dynamic simulations of this system are performed with heat and mass transfer mechanisms due to energy transfer during the phase change interaction near the heat transfer surface. The volume of fluid model in an available Eulerian-Eulerian approach based on finite volume method is utilized and the mass source term in conservation of mass equation is implemented using a user defined function. The characteristics of water flow boiling such as void fraction and heat transfer coefficient distribution are investigated. The main cause of fluctuations on heat transfer coefficient and volume fraction is velocity increment in the vapor phase rather than the liquid phase. The case study of this research including convective heat transfer coefficient and tube diameter are considered as a parametric study. The operating conditions are considered at high pressure in saturation temperature and the physical properties of water are determined by considering system's inlet temperature and pressure in saturation conditions. Good agreement is achieved between the numerical and the experimental values of heat transfer coefficients.

Numerical investigation of saturated upward flow boiling of water in a vertical tube using VOF model: effect of different boundary conditions

NASA Astrophysics Data System (ADS)

Hasanpour, B.; Irandoost, M. S.; Hassani, M.; Kouhikamali, R.

2018-07-01

In this paper a numerical simulation of upward two-phase flow evaporation in a vertical tube has been studied by considering water as working fluid. To this end, the computational fluid dynamic simulations of this system are performed with heat and mass transfer mechanisms due to energy transfer during the phase change interaction near the heat transfer surface. The volume of fluid model in an available Eulerian-Eulerian approach based on finite volume method is utilized and the mass source term in conservation of mass equation is implemented using a user defined function. The characteristics of water flow boiling such as void fraction and heat transfer coefficient distribution are investigated. The main cause of fluctuations on heat transfer coefficient and volume fraction is velocity increment in the vapor phase rather than the liquid phase. The case study of this research including convective heat transfer coefficient and tube diameter are considered as a parametric study. The operating conditions are considered at high pressure in saturation temperature and the physical properties of water are determined by considering system's inlet temperature and pressure in saturation conditions. Good agreement is achieved between the numerical and the experimental values of heat transfer coefficients.

A practical tool for estimating subsurface LNAPL distributions and transmissivity using current and historical fluid levels in groundwater wells: Effects of entrapped and residual LNAPL

NASA Astrophysics Data System (ADS)

Lenhard, R. J.; Rayner, J. L.; Davis, G. B.

2017-10-01

A model is presented to account for elevation-dependent residual and entrapped LNAPL above and below, respectively, the water-saturated zone when predicting subsurface LNAPL specific volume (fluid volume per unit area) and transmissivity from current and historic fluid levels in wells. Physically-based free, residual, and entrapped LNAPL saturation distributions and LNAPL relative permeabilities are integrated over a vertical slice of the subsurface to yield the LNAPL specific volumes and transmissivity. The model accounts for effects of fluctuating water tables. Hypothetical predictions are given for different porous media (loamy sand and clay loam), fluid levels in wells, and historic water-table fluctuations. It is shown the elevation range from the LNAPL-water interface in a well to the upper elevation where the free LNAPL saturation approaches zero is the same for a given LNAPL thickness in a well regardless of porous media type. Further, the LNAPL transmissivity is largely dependent on current fluid levels in wells and not historic levels. Results from the model can aid developing successful LNAPL remediation strategies and improving the design and operation of remedial activities. Results of the model also can aid in accessing the LNAPL recovery technology endpoint, based on the predicted transmissivity.

The effect of progressive hypoxia on school structure and dynamics in Atlantic herring Clupea harengus.

PubMed

Domenici, Paolo; Ferrari, R Silvana; Steffensen, John F; Batty, Robert S

2002-10-22

The effect of progressive hypoxia on the structure and dynamics of herring (Clupea harengus) schools in laboratory conditions was investigated. The length, width and depth of schools of about 20 individuals were measured from video recordings to test the hypothesis that during hypoxia fish schools change their shape and volume. School shape (calculated as the ratios of length/depth, width/depth and length/width) did not change significantly during hypoxia. School length, width, depth, area and volume were all significantly increased at 20% oxygen saturation. Volume, area and width were more sensitive to hypoxia; volume and width were also increased at 25% and area at 30% oxygen saturation. The degree of position changing (shuffling) of individuals within the school was also analysed. Shuffling in normoxia was observed to occur largely through 'O-turn' manoeuvres, a 360( degrees )turn executed laterally to the school that allowed fishes in the front to move to the back. O-turn frequency during normoxia was 0.69 O-turns fish(-1) min(-1) but significantly decreased with hypoxia to 0.37 O-turns fish(-1) min(-1) at 30% oxygen saturation. Shuffling was also investigated by measuring the persistence time of individual herring in leading positions (i.e. the first half of the school). No significant changes occurred during hypoxia, indicating that the decrease in O-turn frequency does not affect shuffling rate during hypoxia, and that position shuffling in hypoxic conditions is mainly due to overtaking or falling back by individual fishes. School integrity and positional dynamics are the outcome of trade-offs among a number of biotic factors, such as food, predator defence, mating behaviour and various physical factors that may impose certain limits. Among these, our results indicate that oxygen level modulates schooling behaviour. Oxygen alters whole-school parameters at oxygen saturation values that can be encountered by herring in the field, indicating that oxygen availability is an important factor in the trade-offs that determine school volume. An increase in school volume in the wild may increase the oxygen available to each individual. However, shuffling rate is not affected by hypoxia, indicating that the internal dynamics of positioning is the result of the balance of other factors, for example related to the nutritional state of each individual fish as suggested by previous studies.

Theory of wave propagation in partially saturated double-porosity rocks: a triple-layer patchy model

NASA Astrophysics Data System (ADS)

Sun, Weitao; Ba, Jing; Carcione, José M.

2016-04-01

Wave-induced local fluid flow is known as a key mechanism to explain the intrinsic wave dissipation in fluid-saturated rocks. Understanding the relationship between the acoustic properties of rocks and fluid patch distributions is important to interpret the observed seismic wave phenomena. A triple-layer patchy (TLP) model is proposed to describe the P-wave dissipation process in a double-porosity media saturated with two immiscible fluids. The double-porosity rock consists of a solid matrix with unique host porosity and inclusions which contain the second type of pores. Two immiscible fluids are considered in concentric spherical patches, where the inner pocket and the outer sphere are saturated with different fluids. The kinetic and dissipation energy functions of local fluid flow (LFF) in the inner pocket are formulated through oscillations in spherical coordinates. The wave propagation equations of the TLP model are based on Biot's theory and the corresponding Lagrangian equations. The P-wave dispersion and attenuation caused by the Biot friction mechanism and the local fluid flow (related to the pore structure and the fluid distribution) are obtained by a plane-wave analysis from the Christoffel equations. Numerical examples and laboratory measurements indicate that P-wave dispersion and attenuation are significantly influenced by the spatial distributions of both, the solid heterogeneity and the fluid saturation distribution. The TLP model is in reasonably good agreement with White's and Johnson's models. However, differences in phase velocity suggest that the heterogeneities associated with double-porosity and dual-fluid distribution should be taken into account when describing the P-wave dispersion and attenuation in partially saturated rocks.

Predicting Impact of Biochar Addition on Soil Hydraulic Properties

NASA Astrophysics Data System (ADS)

Nakhli, S. A. A.; Yudi, Y.; Imhoff, P. T.

2017-12-01

Biochar has been proposed as a soil amendment to improve soil hydraulic properties, including water retention and saturated and unsaturated hydraulic conductivity, for agricultural and environmental applications. However, its effect on hydraulic properties is difficult to predict and often with mixed results: in some cases biochar enhances soil hydraulic properties, while in other cases it degrades them. Despite several published observational studies, there are no models that can reliably predict biochar's impact on soil hydraulic properties. In this project we developed models to describe the effect of addition of a commercial wood biochar pyrolyzed at 550° on soil hydraulic properties in laboratory-scale experiments. The effects of biochar addition at 2% and 6% (w/w) on water retention and saturated and unsaturated hydraulic conductivity were evaluated for silt loam, sandy loam, and loamy sand. The addition of 6% (w/w) biochar increased the available water content of silt loam, sandy loam and loamy sand by 25, 20 and 70%, respectively. The impact of biochar addition on water retention was predicted reasonably well using information on the intra particle pore volume of biochar (mercury porosimetry, N2 and CO2 sorption) and the particle size distribution of the soil/biochar mixture. When amended with 6% biochar, saturated hydraulic conductivity increased 17% for loamy sand, but decreased 30% and 54% for silt loam and sandy loam, respectively. The Kozeny-Carman equation modified to account for changes in inter pore volume predicted saturated hydraulic conductivities of the biochar-amended soils reasonably well, with RMSE ranging from 0.06 to 5.06 cm h-1 for silt loam and loamy sand, respectively. While intra particle pore volume of biochar contributed significantly to higher water retention, changes in hydraulic conductivity were correlated instead with changes in inter pore volume - the large pores between biochar and soil particles.

Outer planet entry probe system study. Volume 4: Common Saturn/Uranus probe studies

NASA Technical Reports Server (NTRS)

1973-01-01

Results are summarized of a common scientific probe study to explore the atmospheres of Saturn and Uranus. This was a three-month follow-on effort to the Outer Planet Entry Probe System study. The report presents: (1) a summary, conclusions and recommendations of this study, (2) parametric analysis conducted to support the two system definitions, (3) common Saturn/Uranus probe system definition using the Science Advisory Group's exploratory payload and, (4) common Saturn/Uranus probe system definition using an expanded science complement. Each of the probe system definitions consists of detailed discussions of the mission, science, system and subsystems including telecommunications, data handling, power, pyrotechnics, attitude control, structures, propulsion, thermal control and probe-to-spacecraft integration. References are made to the contents of the first three volumes where it is feasible to do so.

Shear-enhanced compaction in viscoplastic rocks

NASA Astrophysics Data System (ADS)

Yarushina, V. M.; Podladchikov, Y. Y.

2012-04-01

The phenomenon of mutual influence of compaction and shear deformation was repeatedly reported in the literature over the past years. Dilatancy and shear-enhanced compaction of porous rocks were experimentally observed during both rate-independent and rate-dependent inelastic deformation. Plastic pore collapse was preceding the onset of dilatancy and shear-enhanced compaction. Effective bulk viscosity is commonly used to describe compaction driven fluid flow in porous rocks. Experimental data suggest that bulk viscosity of a fluid saturated rock might be a function of both the effective pressure and the shear stress. Dilatancy and shear-enhanced compaction can alter the transport properties of rocks through their influence on permeability and compaction length scale. Recent investigations show that shear stresses in deep mantle rocks can be responsible for spontaneous development of localized melt-rich bands and segregation of small amounts of melt from the solid rock matrix through shear channeling instability. Usually it is assumed that effective viscosity is a function of porosity only. Thus coupling between compaction and shear deformation is ignored. Spherical model which considers a hollow sphere subjected to homogeneous tractions on the outer boundary as a representative elementary volume succeeded in predicting the volumetric compaction behavior of porous rocks and metals to a hydrostatic pressure in a wide range of porosities. Following the success of this simple model we propose a cylindrical model of void compaction and decompaction due to the non-hydrostatic load. The infinite viscoplastic layer with a cylindrical hole is considered as a representative volume element. The remote boundary of the volume is subjected to a homogeneous non-hydrostatic load such that plane strain conditions are fulfilled through the volume. At some critical values of remote stresses plastic zone develops around the hole. The dependence of the effective bulk viscosity on the properties of individual components as well as on the stress state is examined. We show that bulk viscosity is a function of porosity, effective pressure and shear stress. Decreasing porosity tends to increase bulk viscosity whereas increasing shear stress and increasing effective pressure reduce it.

JT90 Ceramic Outer Air Seal System Refinement Program, Phase 2

NASA Technical Reports Server (NTRS)

Shiembob, L. T.

1982-01-01

The sprayed ceramic gas turbine outer air seal system was tested in two JT9D engines to substantiate the abradability and durability of the seals. Of particular significance was that one of the tests, a 150 hour 1000 cycle endurance program at nominal JT9D operating conditions, was completed with minimal effect on the seals and received Federal Aviation Administration cognizance with respect to potential field service use by the airlines. The other engine test completed 1825 endurance cycles at severe operating conditions and no burn through or other serious defects in the structural integrity of a seal segment was observed. These test results combined with other Pratt and Whitney Aircraft engine tests substantiate the potential of the ceramic outer air seal system to attain the durability goal of 50000 hour engine operating capability. Both engine tests subjected the seals to intentional blade rubs and demonstrated good abradability with volume wear ratios greater than 100, far exceeding the design goal of 10. The improved volume wear ratio will allow the turbine tip clearance to be reduced, thereby resulting in an estimated thrust specific fuel consumption improvement of 0.3 percent.

Innovative Design and Performance Evaluation of Bionic Imprinting Toothed Wheel.

PubMed

Zhang, Zhihong; Wang, Xiaoyang; Tong, Jin; Stephen, Carr

2018-01-01

A highly efficient soil-burrowing dung beetle possesses an intricate outer contour curve on its foreleg end-tooth. This study was carried out based on evidence that this special outer contour curve has the potential of reducing soil penetration resistance and could enhance soil-burrowing efficiency. A toothed wheel is a typical agricultural implement for soil imprinting, to increase its working efficiency; the approach of the bionic geometrical structure was utilized to optimize the innovative shape of imprinting toothed wheel. Characteristics in the dung beetle's foreleg end-tooth were extracted and studied by the edge detection technique. Then, this special outer contour curve was modeled by a nine-order polynomial function and used for the innovative design of imprinting the tooth's cutting edge. Both the conventional and bionic teeth were manufactured, and traction tests in a soil bin were conducted. Taking required draft force and volume of imprinted microbasin as the evaluating indexes, operating efficiency and quality of different toothed wheels were compared and investigated. Results indicate that compared with the conventional toothed wheel, a bionic toothed wheel possesses a better forward resistance reduction property against soil and, meanwhile, can enhance the quality of soil imprinting by increasing the volume of the created micro-basin.

Microphysics of mass-transport in coupled droplet-pairs at low Reynolds number and the role of convective dynamics

NASA Astrophysics Data System (ADS)

Dong, Qingming; Sau, Amalendu

2016-06-01

Interfacial mass-transport and redistribution in the micro-scale liquid droplets are important in diverse fields of research interest. The role of the "inflow" and the "outflow" type convective eddy-pairs in the entrainment of outer solute and internal relocation are examined for different homogeneous and heterogeneous water droplet pairs appearing in a tandem arrangement. Two micro-droplets of pure (rain) water interact with an oncoming outer air stream (Re ≤ 100) contaminated by uniformly distributed SO2. By virtue of separation/attachment induced non-uniform interfacial shear-stress gradient, the well-defined inflow/outflow type pairs of recirculating eddy-based convective motion quickly develops, and the eddies effectively attract/repel the accumulated outer solute and control the physical process of mass-transport in the droplet-pair. The non-uniformly shear-driven flow interaction and bifurcation of the circulatory internal flow lead to growth of important micro-scale "secondary" eddies which suitably regroup with the adjacent "primary" one to create the sustained inflow/outflow type convective dynamics. The presently derived flow characteristics and in-depth analysis help to significantly improve our understanding of the micro-droplet based transport phenomena in a wider context. By tuning "Re" (defined in terms of the droplet diameter and the average oncoming velocity of the outer air) and gap-ratio "α," the internal convective forcing and the solute entrainment efficiency could be considerably enhanced. The quantitative estimates for mass entrainment, convective strength, and saturation characteristics for different coupled micro-droplet pairs are extensively examined here for 0.2 ≤ α ≤ 2.0 and 30 ≤ Re ≤ 100. Interestingly, for the compound droplets, with suitably tuned radius-ratio "B" (of upstream droplet with respect to downstream one) the generated "inflow" type coherent convective dynamics helped to significantly augment the centre-line mass flow, which in turn facilitate faster saturation of the upstream droplet. However, for heterogeneous droplet-pairs containing solid nucleus, while increased solid-fraction "S" (the ratio between the radius of the solid nucleus and that of the droplet) through 0.25 ≤ S ≤ 0.45 caused gradual reductions of convective strength and mass absorption rate (RSO2) for the upstream droplet, beyond a critical value S ≥ 0.45 the RSO2 therein continued to rise again owing to the reduced film thickness.

Flowmeter and Ground Penetrating Radar: comparison between hydrogeological and geophysical methods

NASA Astrophysics Data System (ADS)

Villa, A.; Basirico', S.; Arato, A.; Crosta, G. B.; Frattini, P.; Godio, A.

2012-04-01

A comparison between saturated hydraulic conductivity calculated with Electromagnetic Borehole Flowmeter (EBF) and water content obtained by Ground Penetrating Radar (GPR) Zero Offset Profile (ZOP) is presented. EBF technique permits to obtain permeability profiles along one borehole in the saturated zone by using the Moltz (1993) method. The analysis of ZOP data provides information about the water content (Topp, 1980) in the section between two adjacent boreholes. Water content profiles in the saturated zone can be related to the porosity of the medium which, together with the permeability from EBF measurements, is fundamental for any hydrogeological characterization. These two methods have been applied to three different test-sites located in the Northern Italy. A first site regards a complex aquifer, characterized by a chaotic sequence of gypsum-marls. The other two sites are characterized by an alternation of sandy and silty-sandy layers. For each site, we adopted the EBF along screened boreholes with 0.25 m spacing, under ambient and stressed conditions. The cross-hole georadar survey was performed within the saturated zone by using 100 Hz borehole antennas with 0.25 m spacing. The results from the analysis of EBF and ZOP profiles show a general positive correlation between permeability and water content and porosity. This is reasonable for granular soils where the permeability is controlled by the pore space available for water flow, i.e., the effective porosity. For this soils, where EBF permeability and ZOP water-content profiles are in good agreement, the volume between the boreholes can be supposed to be homogeneous. On the other hand, a poor correlation suggests the presence of heterogeneity between the boreholes, which can be observed because the two techniques involve different volumes of soil: the EBF permeability refers to a portion of volume just around the borehole while the ZOP investigates the entire volume between the two boreholes. The poor correlation could be enhanced when enlarging the borehole separation, because the difference in the involved volume between the two techniques increases. Finally, the degree of correlation between the EBF permeability profile and the ZOP water content profile can indicate how much the volume investigated by EBF is effectively representative of the entire volume between the boreholes. Molz, F.J. and S.C. Young, 1993. Development and Application of Borehole Flowmeters for Environmental Assessment, The Log Analyst, 13-23. Topp G.C., J.L. Davis and A.P. Annan, 1980. Electromagnetic determination of soil water content: measurements in coaxial transmission lines, Water Resources Research, 16, 574-582.

IMAGING AND MEASUREMENT OF THE PRERETINAL SPACE IN VITREOMACULAR ADHESION AND VITREOMACULAR TRACTION BY A NEW SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY ANALYSIS.

PubMed

Stopa, Marcin; Marciniak, Elżbieta; Rakowicz, Piotr; Stankiewicz, Agnieszka; Marciniak, Tomasz; Dąbrowski, Adam

2017-10-01

To evaluate a new method for volumetric imaging of the preretinal space (also known as the subhyaloid, subcortical, or retrocortical space) and investigate differences in preretinal space volume in vitreomacular adhesion (VMA) and vitreomacular traction (VMT). Nine patients with VMA and 13 with VMT were prospectively evaluated. Automatic inner limiting membrane line segmentation, which exploits graph search theory implementation, and posterior cortical vitreous line segmentation were performed on 141 horizontal spectral domain optical coherence tomography B-scans per patient. Vertical distances (depths) between the posterior cortical vitreous and inner limiting membrane lines were calculated for each optical coherence tomography B-scan acquired. The derived distances were merged and visualized as a color depth map that represented the preretinal space between the posterior surface of the hyaloid and the anterior surface of the retina. The early treatment d retinopathy study macular map was overlaid onto final virtual maps, and preretinal space volumes were calculated for each early treatment diabetic retinopathy study map sector. Volumetric maps representing preretinal space volumes were created for each patient in the VMA and VMT groups. Preretinal space volumes were larger in all early treatment diabetic retinopathy study map macular regions in the VMT group compared with those in the VMA group. The differences reached statistical significance in all early treatment diabetic retinopathy study sectors, except for the superior outer macula and temporal outer macula where significance values were P = 0.05 and P = 0.08, respectively. Overall, the relative differences in preretinal space volumes between the VMT and VMA groups varied from 2.7 to 4.3 in inner regions and 1.8 to 2.9 in outer regions. Our study provides evidence of significant differences in preretinal space volume between eyes with VMA and those with VMT. This may be useful not only in the investigation of preretinal space properties in VMA and VMT, but also in other conditions, such as age-related macular degeneration, diabetic retinopathy, and central retinal vein occlusion.

An interpretation of core and wireline logs for the Petrophysical evaluation of Upper Shallow Marine sandstone reservoirs of the Bredasdorp Basin, offshore South Africa

NASA Astrophysics Data System (ADS)

Magoba, Moses; Opuwari, Mimonitu

2017-04-01

This paper embodies a study carried out to assess the Petrophysical evaluation of upper shallow marine sandstone reservoir of 10 selected wells in the Bredasdorp basin, offshore, South Africa. The studied wells were selected randomly across the upper shallow marine formation with the purpose of conducting a regional study to assess the difference in reservoir properties across the formation. The data sets used in this study were geophysical wireline logs, Conventional core analysis and geological well completion report. The physical rock properties, for example, lithology, fluid type, and hydrocarbon bearing zone were qualitatively characterized while different parameters such as volume of clay, porosity, permeability, water saturation ,hydrocarbon saturation, storage and flow capacity were quantitatively estimated. The quantitative results were calibrated with the core data. The upper shallow marine reservoirs were penetrated at different depth ranging from shallow depth of about 2442m to 3715m. The average volume of clay, average effective porosity, average water saturation, hydrocarbon saturation and permeability range from 8.6%- 43%, 9%- 16%, 12%- 68% , 32%- 87.8% and 0.093mD -151.8mD respectively. The estimated rock properties indicate a good reservoir quality. Storage and flow capacity results presented a fair to good distribution of hydrocarbon flow.

Oil-spill risk analysis: Cook inlet outer continental shelf lease sale 149. Volume 2: Conditional risk contour maps of seasonal conditional probabilities. Final report

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

Johnson, W.R.; Marshall, C.F.; Anderson, C.M.

1994-08-01

The Federal Government has proposed to offer Outer Continental Shelf (OCS) lands in Cook Inlet for oil and gas leasing. Because oil spills may occur from activities associated with offshore oil production, the Minerals Management Service conducts a formal risk assessment. In evaluating the significance of accidental oil spills, it is important to remember that the occurrence of such spills is fundamentally probabilistic. The effects of oil spills that could occur during oil and gas production must be considered. This report summarizes results of an oil-spill risk analysis conducted for the proposed Cook Inlet OCS Lease Sale 149. The objectivemore » of this analysis was to estimate relative risks associated with oil and gas production for the proposed lease sale. To aid the analysis, conditional risk contour maps of seasonal conditional probabilities of spill contact were generated for each environmental resource or land segment in the study area. This aspect is discussed in this volume of the two volume report.« less

Mixing of biogenic siliceous and terrigenous clastic sediments: South Belridge field and Beta field, California

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

Schwartz, D.E.

1990-05-01

The intermixing and interbedding of biogenically derived siliceous sediment with terrigenous clastic sediment in reservoirs of upper Miocene age provides both reservoir rock and seal and influences productivity by affecting porosity and permeability. Miocene reservoirs commonly contain either biogenic-dominated cyclic diatomite, porcelanite, or chert (classic Monterey Formation) or clastic-dominated submarine fan sequences with interbedded or intermixed siliceous members of biogenic origin. Biogenic-clastic cycles, 30-180 ft thick, at South Belridge field were formed by episodic influx of clastic sediment from distant submarine fans mixing with slowly accumulating diatomaceous ooze. The cycles consist of basal silt and pelletized massive diatomaceous mudstone, overlainmore » by burrowed, faintly bedded clayey diatomite and topped by laminated diatomite. Cycle tops have higher porosity and permeability, lower grain density, and higher oil saturation than clay and silt-rich portions of the cycles. Submarine fan sediments forming reservoirs at the Beta field are comprised of interbedded sands and silts deposited in a channelized middle fan to outer fan setting. Individual turbidites display fining-upward sequences, with oil-bearing sands capped by wet micaceous silts. Average sands are moderately to poorly sorted, fine- to medium-grained arkosic arenites. Sands contain pore-filling carbonate and porcelaneous cements. Porcelaneous cement consists of a mixture of opal-A, opal-CT, and chert with montmorillonite and minor zeolite. This cement is an authigenic material precipitated in intergranular pore space. The origin of the opal is biogenic, with recrystallization of diatom frustules (opal-A) into opal-CT lepispheres and quartz crystals. Porcelaneous cement comprises 4-21% of the bulk volume of the rock. Seventy percent of the bulk volume of the cement is micropore space.« less

Influence of the membrane environment on cholesterol transfer.

PubMed

Breidigan, Jeffrey Michael; Krzyzanowski, Natalie; Liu, Yangmingyue; Porcar, Lionel; Perez-Salas, Ursula

2017-12-01

Cholesterol, an essential component in biological membranes, is highly unevenly distributed within the cell, with most localized in the plasma membrane while only a small fraction is found in the endoplasmic reticulum, where it is synthesized. Cellular membranes differ in lipid composition and protein content, and these differences can exist across their leaflets too. This thermodynamic landscape that cellular membranes impose on cholesterol is expected to modulate its transport. To uncover the role the membrane environment has on cholesterol inter- and intra-membrane movement, we used time-resolved small angle neutron scattering to study the passive movement of cholesterol between and within membranes with varying degrees of saturation content. We found that cholesterol moves systematically slower as the degree of saturation in the membranes increases, from a palmitoyl oleyl phosphotidylcholine membrane, which is unsaturated, to a dipalmitoylphosphatidylcholine (DPPC) membrane, which is fully saturated. Additionally, we found that the energetic barrier to move cholesterol in these phosphatidylcholine membranes is independent of their relative lipid composition and remains constant for both flip-flop and exchange at ∼100 kJ/mol. Further, by replacing DPPC with the saturated lipid palmitoylsphingomyelin, an abundant saturated lipid of the outer leaflet of the plasma membrane, we found the rates decreased by a factor of two. This finding is in stark contrast with recent molecular dynamic simulations that predict a dramatic slow-down of seven orders of magnitude for cholesterol flipping in membranes with a similar phosphocholine and SM lipid composition. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

Impact of Fe powder sintering and soldering in production of porous heating surface on flow boiling heat transfer in minichannels

NASA Astrophysics Data System (ADS)

Depczyński, Wojciech; Piasecki, Artur; Piasecka, Magdalena; Strąk, Kinga

2017-10-01

This paper focuses on identification of the impact of porous heated surface on flow boiling heat transfer in a rectangular minichannel. The heated element for Fluorinert FC-72 was a thin plate made of Haynes-230. Infrared thermography was used to determine changes in the temperature on its outer smooth side. The porous surface in contact with the fluid in the minichannel was produced in two processes: sintering or soldering of Fe powder to the plate. The results were presented as relationships between the heat transfer coefficient and the distance from the minichannel inlet and as boiling curves. Results obtained for using a smooth heated plate at the saturated boiling region were also presented to compare. In the subcooled boiling region, at a higher heat flux, the heat transfer coefficient was slightly higher for the surface prepared via soldering. In the saturated boiling region, the local heat transfer coefficients obtained for the smooth plate surface were slightly higher than those achieved from the sintered plate surface. The porous structures formed have low thermal conductivity. This may induce noticeable thermal resistance at the diffusion bridges of the sintered structures, in particular within the saturated boiling region.

Differences in surfactant lipids collected from pleural and pulmonary lining fluids.

PubMed

Mills, Paul C; Chen, Yi; Hills, Yvette C; Hills, Brian A

2005-11-01

The type and relative importance of saturated and unsaturated phospholipid components of surfactant within the epithelial lining fluid (ELF) of the inner and outer surfaces of the lung is not known. Seven healthy dogs were anesthetized and a bronchoalveolar lavage (BAL) was performed, immediately followed by a pleural lavage (PL). Lipid was extracted from lavage fluid and then analyzed for saturated, primarily dipalmitoylphosphatidylcholine (DPPC), and unsaturated phosphatidylcholine (PC) species using high-performance liquid chromatography (HPLC) with combined fluorescence and ultraviolet detection. Dilution of ELF in lavage fluids was corrected for using the urea method. DPPC (494.7 +/- 213.9 microg/mL) was the predominant PC present in ELF collected from the alveolar surface. In contrast, significantly higher (p = 0.028) proportions of unsaturated PC species were measured in PL fluid (approximately 105 microg/mL), particularly stearoyl-linoleoyl-phosphatidylcholine (SLPC), which could not be measured in fluid collected from the alveoli, compared to DPPC (2.6 +/- 2.0 microg/mL). This study indicates that unsaturated PC species seem to be more important than saturated species, particularly DPPC, in the pleural cavity, which has implications for surfactant replenishment following pleural disease or thoracic surgery.

Analytical model of a corona discharge from a conical electrode under saturation

NASA Astrophysics Data System (ADS)

Boltachev, G. Sh.; Zubarev, N. M.

2012-11-01

Exact partial solutions are found for the electric field distribution in the outer region of a stationary unipolar corona discharge from an ideal conical needle in the space-charge-limited current mode with allowance for the electric field dependence of the ion mobility. It is assumed that only the very tip of the cone is responsible for the discharge, i.e., that the ionization zone is a point. The solutions are obtained by joining the spherically symmetric potential distribution in the drift space and the self-similar potential distribution in the space-charge-free region. Such solutions are outside the framework of the conventional Deutsch approximation, according to which the space charge insignificantly influences the shape of equipotential surfaces and electric lines of force. The dependence is derived of the corona discharge saturation current on the apex angle of the conical electrode and applied potential difference. A simple analytical model is suggested that describes drift in the point-plane electrode geometry under saturation as a superposition of two exact solutions for the field potential. In terms of this model, the angular distribution of the current density over the massive plane electrode is derived, which agrees well with Warburg's empirical law.

Simulating adsorptive expansion of zeolites: application to biomass-derived solutions in contact with silicalite.

PubMed

Santander, Julian E; Tsapatsis, Michael; Auerbach, Scott M

2013-04-16

We have constructed and applied an algorithm to simulate the behavior of zeolite frameworks during liquid adsorption. We applied this approach to compute the adsorption isotherms of furfural-water and hydroxymethyl furfural (HMF)-water mixtures adsorbing in silicalite zeolite at 300 K for comparison with experimental data. We modeled these adsorption processes under two different statistical mechanical ensembles: the grand canonical (V-Nz-μg-T or GC) ensemble keeping volume fixed, and the P-Nz-μg-T (osmotic) ensemble allowing volume to fluctuate. To optimize accuracy and efficiency, we compared pure Monte Carlo (MC) sampling to hybrid MC-molecular dynamics (MD) simulations. For the external furfural-water and HMF-water phases, we assumed the ideal solution approximation and employed a combination of tabulated data and extended ensemble simulations for computing solvation free energies. We found that MC sampling in the V-Nz-μg-T ensemble (i.e., standard GCMC) does a poor job of reproducing both the Henry's law regime and the saturation loadings of these systems. Hybrid MC-MD sampling of the V-Nz-μg-T ensemble, which includes framework vibrations at fixed total volume, provides better results in the Henry's law region, but this approach still does not reproduce experimental saturation loadings. Pure MC sampling of the osmotic ensemble was found to approach experimental saturation loadings more closely, whereas hybrid MC-MD sampling of the osmotic ensemble quantitatively reproduces such loadings because the MC-MD approach naturally allows for locally anisotropic volume changes wherein some pores expand whereas others contract.

THE MECHANISM OF ACTION OF COLCHICINE

PubMed Central

Wilson, Leslie; Meza, Isaura

1973-01-01

The thermal depolymerization procedure of Stephens (1970. J. Mol. Biol. 47:353) has been employed for solubilization of Strongylocentrotus purpuratus sperm tail outer doublet microtubules with the use of a buffer during solubilization which is of optimal pH and ionic strength for the preservation of colchicine binding activity of chick embryo brain tubulin. Colchicine binding values were corrected for first-order decay during heat solubilization at 50°C (t½ = 5.4 min) and incubation with colchicine at 37°C in the presence of vinblastine sulfate (t½ = 485 min). The colchicine binding properties of heat-solubilized outer doublet tubulin were qualitatively identical with those of other soluble forms of tubulin. The solubilized tubulin (mol wt, 115,000) bound 0.9 ± 0.2 mol of colchicine per mol of tubulin, with a binding constant of 6.3 x 105 liters/mol at 37°C. The colchicine binding reaction was both time and temperature dependent, and the binding of colchicine was prevented in a competitive manner by podophyllotoxin (Ki = 1.3 x 10-6 M). The first-order decay of colchicine binding activity was substantially decreased by the addition of the vinca alkaloids, vinblastine sulfate or vincristine sulfate, thus demonstrating the presence of a vinca alkaloid binding site(s) on the outer doublet tubulin. Tubulin contained within the assembled microtubules did not decay. Intact outer doublet microtubules bound less than 0.001 mol of colchicine per mol of tubulin contained in the microtubules, under conditions where soluble tubulin would have bound 1 mol of colchicine per mol of tubulin (saturating concentration of colchicine, no decay of colchicine binding activity). The presence of colchicine had no effect on the rate of solubilization of outer doublet microtubules during incubation at 37°C. Therefore, the colchicine binding site on tubulin is blocked (not available to bind colchicine) when the tubulin is in the assembled outer doublet microtubules. PMID:4747924

Impacts of age and sex on retinal layer thicknesses measured by spectral domain optical coherence tomography with Spectralis.

PubMed

Nieves-Moreno, María; Martínez-de-la-Casa, José M; Morales-Fernández, Laura; Sánchez-Jean, Rubén; Sáenz-Francés, Federico; García-Feijoó, Julián

2018-01-01

To examine differences in individual retinal layer thicknesses measured by spectral domain optical coherence tomography (SD-OCT) (Spectralis®) produced with age and according to sex. Cross-sectional, observational study. The study was conducted in 297 eyes of 297 healthy subjects aged 18 to 87 years. In one randomly selected eye of each participant the volume and mean thicknesses of the different macular layers were measured by SD-OCT using the instrument's macular segmentation software. Volume and mean thickness of macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retinal pigmentary epithelium (RPE) and photoreceptor layer (PR). Retinal thickness was reduced by 0.24 μm for every one year of age. Age adjusted linear regression analysis revealed mean GCL, IPL, ONL and PR thickness reductions and a mean OPL thickness increase with age. Women had significantly lower mean GCL, IPL, INL, ONL and PR thicknesses and volumes and a significantly greater mRNFL volume than men. The thickness of most retinal layers varies both with age and according to sex. Longitudinal studies are needed to determine the rate of layer thinning produced with age.

AGE Bio Diesel Emissions Evaluation

DTIC Science & Technology

2003-12-01

329 44 788 Vratd) Standard Meter Volume, m° 1.336 1.214 1.255 1,268 am Average Sampling Rate, dscfm 0786 0 714 0 739 0 746 P, Stack Pressure, inches...sat) Moisture (at saturation), % by volume 70864 248 8 36676 V.d Standard Water Vapor Volume, ft’ 2.198 1 624 1 911 1-B• Dry Mole Fraction 0 941 0946...Clock Meter Dry Gas Sample Time, Volume, Rotameter Meter Temp., Vacuum, Probe Time (min) (24-hr) (liter) Setting (OF) (in.Hg) jTpr, OF /o5 f / 52 / 6 14V_

A practical tool for estimating subsurface LNAPL distributions and transmissivity using current and historical fluid levels in groundwater wells: Effects of entrapped and residual LNAPL.

PubMed

Lenhard, R J; Rayner, J L; Davis, G B

2017-10-01

A model is presented to account for elevation-dependent residual and entrapped LNAPL above and below, respectively, the water-saturated zone when predicting subsurface LNAPL specific volume (fluid volume per unit area) and transmissivity from current and historic fluid levels in wells. Physically-based free, residual, and entrapped LNAPL saturation distributions and LNAPL relative permeabilities are integrated over a vertical slice of the subsurface to yield the LNAPL specific volumes and transmissivity. The model accounts for effects of fluctuating water tables. Hypothetical predictions are given for different porous media (loamy sand and clay loam), fluid levels in wells, and historic water-table fluctuations. It is shown the elevation range from the LNAPL-water interface in a well to the upper elevation where the free LNAPL saturation approaches zero is the same for a given LNAPL thickness in a well regardless of porous media type. Further, the LNAPL transmissivity is largely dependent on current fluid levels in wells and not historic levels. Results from the model can aid developing successful LNAPL remediation strategies and improving the design and operation of remedial activities. Results of the model also can aid in accessing the LNAPL recovery technology endpoint, based on the predicted transmissivity. Copyright © 2017 Commonwealth Scientific and Industrial Research Organisation - Copyright 2017. Published by Elsevier B.V. All rights reserved.

Single well tracer method to evaluate enhanced recovery

DOEpatents

Sheely, Jr., Clyde Q.; Baldwin, Jr., David E.

1978-01-01

Data useful to evaluate the effectiveness of or to design an enhanced recovery process (the recovery process involving mobilizing and moving hydrocarbons through a hydrocarbon-bearing subterranean formation from an injection well to a production well by injecting a mobilizing fluid into the injection well) are obtained by a process which comprises sequentially: determining hydrocarbon saturation in the formation in a volume in the formation near a well bore penetrating the formation, injecting sufficient of the mobilizing fluid to mobilize and move hydrocarbons from a volume in the formation near the well bore penetrating the formation, and determining by the single well tracer method a hydrocarbon saturation profile in a volume from which hydrocarbons are moved. The single well tracer method employed is disclosed by U.S. Pat. No. 3,623,842. The process is useful to evaluate surfactant floods, water floods, polymer floods, CO.sub.2 floods, caustic floods, micellar floods, and the like in the reservoir in much less time at greatly reduced costs, compared to conventional multi-well pilot test.

Investigation, development and application of optimal output feedback theory. Volume 2: Development of an optimal, limited state feedback outer-loop digital flight control system for 3-D terminal area operation

NASA Technical Reports Server (NTRS)

Broussard, J. R.; Halyo, N.

1984-01-01

This report contains the development of a digital outer-loop three dimensional radio navigation (3-D RNAV) flight control system for a small commercial jet transport. The outer-loop control system is designed using optimal stochastic limited state feedback techniques. Options investigated using the optimal limited state feedback approach include integrated versus hierarchical control loop designs, 20 samples per second versus 5 samples per second outer-loop operation and alternative Type 1 integration command errors. Command generator tracking techniques used in the digital control design enable the jet transport to automatically track arbitrary curved flight paths generated by waypoints. The performance of the design is demonstrated using detailed nonlinear aircraft simulations in the terminal area, frequency domain multi-input sigma plots, frequency domain single-input Bode plots and closed-loop poles. The response of the system to a severe wind shear during a landing approach is also presented.

Optimal probes for withdrawal of uncontaminated fluid samples

NASA Astrophysics Data System (ADS)

Sherwood, J. D.

2005-08-01

Withdrawal of fluid by a composite probe pushed against the face z =0 of a porous half-space z >0 is modeled assuming incompressible Darcy flow. The probe is circular, of radius a, with an inner sampling section of radius αa and a concentric outer guard probe αa βa is saturated with fluid 2; the two fluids have the same viscosity. It is assumed that the interface between the two fluids is sharp and remains so as it moves through the rock. The pressure in the probe is lower than that of the pore fluid in the rock, so that the fluid interface is convected with the fluids towards the probe. This idealized axisymmetric problem is solved numerically, and it is shown that an analysis based on far-field spherical flow towards a point sink is a good approximation when the nondimensional depth of fluid 1 is large, i.e., β ≫1. The inner sampling probe eventually produces pure fluid 2, and this technique has been proposed for sampling pore fluids in rock surrounding an oil well [A. Hrametz, C. Gardner, M. Wais, and M. Proett, U.S. Patent No. 6,301,959 B1 (16 October 2001)]. Fluid 1 is drilling fluid filtrate, which has displaced the original pore fluid (fluid 2), a pure sample of which is required. The time required to collect an uncontaminated sample of original pore fluid can be minimized by a suitable choice of the probe geometry α [J. Sherwood, J. Fitzgerald and B. Hill, U.S. Patent No. 6,719,049 B2 (13 April 2004)]. It is shown that the optimal choice of α depends on the depth of filtrate invasion β and the volume of sample required.

Debris Flows and Road Damage Following a Wildfire in 2014 on the Klamath National Forest, Northern California, Near the Community of Seiad, CA

NASA Astrophysics Data System (ADS)

De La Fuente, J. A.; Mikulovsky, R. P.

2016-12-01

Wildfires in summer 2014 burned more than 200,000 acres on the Klamath National Forest in Northern California, east of Seiad, CA. Much of the area burned at high and moderate severity, and is underlain by Slinkard Pluton granitic rock. During winter 2014-2015, there were a few debris flows in small streams, and some clogged culverts on the road system, but overall road damage was minor. In July of 2015, a strong convective storm triggered several large debris flows, including East Fork Walker and No Name Creeks. These and other debris flows damaged road stream crossings, and delivered a large volume of sediment to the stream network. LiDAR differencing is being used to identify and quantify erosion and deposition from that storm. Field inventories revealed widespread rills and small gullies on steep, burned hillslopes, particularly where underlain by granitic rock. Resulting debris flows were of the sediment bulking variety, and no landslide-triggered debris flows were observed. This may be because intense summer storms are of short duration, and are unlikely to saturate the surface mantle, due also to water repellant soil conditions. It is unknown if erosion during the first winter affected the response to the July storm. Storms around January 17, 2016 initiated many road fill failures, and most were limited to the outer half of the road. Field investigations revealed that granitic road fills failed in a variety of settings, including planar hillslopes, on the flanks of ridges, channel crossings, and at road dips. In virtually all cases, vegetation on the fills, up to 50 years old, had been killed by the 2014 fire. Some fills developed small cracks and scarps, whereas others failed catastrophically as debris slides/flows. Few sediment-bulking debris flows were observed in January, 2016. Road damage exceeded two million dollars, and qualified for Emergency Relief Federally Owned funding (ERFO). The effects of the July, 2015 storm were dominated by sheet wash, rilling, flooding, and debris flows, and road damage was concentrated at stream crossings. In contrast, storms in winter 2015-2016 produced many road fill failures, often far from stream crossings, and these were probably associated with deeper saturation of the regolith. Thus, it is critical that road repair measures address both overland flow and saturation responses.

The use of zeolites to generate PET phantoms for the validation of quantification strategies in oncology.

PubMed

Zito, Felicia; De Bernardi, Elisabetta; Soffientini, Chiara; Canzi, Cristina; Casati, Rosangela; Gerundini, Paolo; Baselli, Giuseppe

2012-09-01

In recent years, segmentation algorithms and activity quantification methods have been proposed for oncological (18)F-fluorodeoxyglucose (FDG) PET. A full assessment of these algorithms, necessary for a clinical transfer, requires a validation on data sets provided with a reliable ground truth as to the imaged activity distribution, which must be as realistic as possible. The aim of this work is to propose a strategy to simulate lesions of uniform uptake and irregular shape in an anthropomorphic phantom, with the possibility to easily obtain a ground truth as to lesion activity and borders. Lesions were simulated with samples of clinoptilolite, a family of natural zeolites of irregular shape, able to absorb aqueous solutions of (18)F-FDG, available in a wide size range, and nontoxic. Zeolites were soaked in solutions of (18)F-FDG for increasing times up to 120 min and their absorptive properties were characterized as function of soaking duration, solution concentration, and zeolite dry weight. Saturated zeolites were wrapped in Parafilm, positioned inside an Alderson thorax-abdomen phantom and imaged with a PET-CT scanner. The ground truth for the activity distribution of each zeolite was obtained by segmenting high-resolution finely aligned CT images, on the basis of independently obtained volume measurements. The fine alignment between CT and PET was validated by comparing the CT-derived ground truth to a set of zeolites' PET threshold segmentations in terms of Dice index and volume error. The soaking time necessary to achieve saturation increases with zeolite dry weight, with a maximum of about 90 min for the largest sample. At saturation, a linear dependence of the uptake normalized to the solution concentration on zeolite dry weight (R(2) = 0.988), as well as a uniform distribution of the activity over the entire zeolite volume from PET imaging were demonstrated. These findings indicate that the (18)F-FDG solution is able to saturate the zeolite pores and that the concentration does not influence the distribution uniformity of both solution and solute, at least at the trace concentrations used for zeolite activation. An additional proof of uniformity of zeolite saturation was obtained observing a correspondence between uptake and adsorbed volume of solution, corresponding to about 27.8% of zeolite volume. As to the ground truth for zeolites positioned inside the phantom, the segmentation of finely aligned CT images provided reliable borders, as demonstrated by a mean absolute volume error of 2.8% with respect to the PET threshold segmentation corresponding to the maximum Dice. The proposed methodology allowed obtaining an experimental phantom data set that can be used as a feasible tool to test and validate quantification and segmentation algorithms for PET in oncology. The phantom is currently under consideration for being included in a benchmark designed by AAPM TG211, which will be available to the community to evaluate PET automatic segmentation methods.

Formation of a White-Light Jet Within a Quadrupolar Magnetic Configuration

NASA Astrophysics Data System (ADS)

Filippov, Boris; Koutchmy, Serge; Tavabi, Ehsan

2013-08-01

We analyze multi-wavelength and multi-viewpoint observations of a large-scale event viewed on 7 April 2011, originating from an active-region complex. The activity leads to a white-light jet being formed in the outer corona. The topology and evolution of the coronal structures were imaged in high resolution using the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). In addition, large field-of-view images of the corona were obtained using the Sun Watcher using Active Pixel System detector and Image Processing (SWAP) telescope onboard the PRoject for Onboard Autonomy (PROBA2) microsatellite, providing evidence for the connectivity of the coronal structures with outer coronal features that were imaged with the Large Angle Spectrometric Coronagraph (LASCO) C2 on the S olar and Heliospheric Observatory (SOHO). The data sets reveal an Eiffel-tower type jet configuration extending into a narrow jet in the outer corona. The event starts from the growth of a dark area in the central part of the structure. The darkening was also observed in projection on the disk by the Solar TErrestrial RElations Observatory-Ahead (STEREO-A) spacecraft from a different point of view. We assume that the dark volume in the corona descends from a coronal cavity of a flux rope that moved up higher in the corona but still failed to erupt. The quadrupolar magnetic configuration corresponds to a saddle-like shape of the dark volume and provides a possibility for the plasma to escape along the open field lines into the outer corona, forming the white-light jet.

Automated segmentation of mouse OCT volumes (ASiMOV): Validation & clinical study of a light damage model.

PubMed

Antony, Bhavna Josephine; Kim, Byung-Jin; Lang, Andrew; Carass, Aaron; Prince, Jerry L; Zack, Donald J

2017-01-01

The use of spectral-domain optical coherence tomography (SD-OCT) is becoming commonplace for the in vivo longitudinal study of murine models of ophthalmic disease. Longitudinal studies, however, generate large quantities of data, the manual analysis of which is very challenging due to the time-consuming nature of generating delineations. Thus, it is of importance that automated algorithms be developed to facilitate accurate and timely analysis of these large datasets. Furthermore, as the models target a variety of diseases, the associated structural changes can also be extremely disparate. For instance, in the light damage (LD) model, which is frequently used to study photoreceptor degeneration, the outer retina appears dramatically different from the normal retina. To address these concerns, we have developed a flexible graph-based algorithm for the automated segmentation of mouse OCT volumes (ASiMOV). This approach incorporates a machine-learning component that can be easily trained for different disease models. To validate ASiMOV, the automated results were compared to manual delineations obtained from three raters on healthy and BALB/cJ mice post LD. It was also used to study a longitudinal LD model, where five control and five LD mice were imaged at four timepoints post LD. The total retinal thickness and the outer retina (comprising the outer nuclear layer, and inner and outer segments of the photoreceptors) were unchanged the day after the LD, but subsequently thinned significantly (p < 0.01). The retinal nerve fiber-ganglion cell complex and the inner plexiform layers, however, remained unchanged for the duration of the study.

Automated segmentation of mouse OCT volumes (ASiMOV): Validation & clinical study of a light damage model

PubMed Central

Lang, Andrew; Carass, Aaron; Prince, Jerry L.; Zack, Donald J.

2017-01-01

The use of spectral-domain optical coherence tomography (SD-OCT) is becoming commonplace for the in vivo longitudinal study of murine models of ophthalmic disease. Longitudinal studies, however, generate large quantities of data, the manual analysis of which is very challenging due to the time-consuming nature of generating delineations. Thus, it is of importance that automated algorithms be developed to facilitate accurate and timely analysis of these large datasets. Furthermore, as the models target a variety of diseases, the associated structural changes can also be extremely disparate. For instance, in the light damage (LD) model, which is frequently used to study photoreceptor degeneration, the outer retina appears dramatically different from the normal retina. To address these concerns, we have developed a flexible graph-based algorithm for the automated segmentation of mouse OCT volumes (ASiMOV). This approach incorporates a machine-learning component that can be easily trained for different disease models. To validate ASiMOV, the automated results were compared to manual delineations obtained from three raters on healthy and BALB/cJ mice post LD. It was also used to study a longitudinal LD model, where five control and five LD mice were imaged at four timepoints post LD. The total retinal thickness and the outer retina (comprising the outer nuclear layer, and inner and outer segments of the photoreceptors) were unchanged the day after the LD, but subsequently thinned significantly (p < 0.01). The retinal nerve fiber-ganglion cell complex and the inner plexiform layers, however, remained unchanged for the duration of the study. PMID:28817571

Retinal single-layer analysis with optical coherence tomography shows inner retinal layer thinning in Huntington's disease as a potential biomarker.

PubMed

Gulmez Sevim, Duygu; Unlu, Metin; Gultekin, Murat; Karaca, Cagatay

2018-02-12

There have been ongoing clinical trials of therapeutic agents in Huntington's disease (HD) which requires development of reliable biomarkers of disease progression. There have been studies in the literature with conflicting results on the involvement of retina in HD, and up to date there is not a study evaluating the single retinal layers in HD. We aimed to evaluate the specific retinal changes in HD and their usability as potential disease progression markers. This cross-sectional study used spectral-domain optical coherence tomography with automatic segmentation to measure peripapillary retinal nerve fiber layer (pRNFL) thickness and the thickness and volume of retinal layers in foveal scans of 15 patients with HD and 15 age- and sex-matched controls. Genetic testing results, disease duration, HD disease burden scores and Unified HD Rating Scales motor scores were acquired for the patients. Temporal pRNFL, macular RNFL (mRNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer and outer plexiform layer thicknesses and IPL, retinal pigment epithelium and outer macular volume were found lower in HD compared to controls, while outer nuclear layer and outer retinal layer thickness were increased (p < 0.05). We found significant correlations between inner retinal layer thicknesses, most significantly with mRNFL and GCL and disease progression markers. The outcomes of this study points out that retinal layers, most significantly mRNFL and GCL, are strongly correlated with the disease progression in HD and could serve as useful biomarkers for disease progression.

The Density of Mid-sized Kuiper Belt Objects from ALMA Thermal Observations

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

Brown, Michael E.; Butler, Bryan J.

The densities of mid-sized Kuiper Belt objects (KBOs) are a key constraint in understanding the assembly of objects in the outer solar system. These objects are critical for understanding the currently unexplained transition from the smallest KBOs with densities lower than that of water, to the largest objects with significant rock content. Mapping this transition is made difficult by the uncertainties in the diameters of these objects, which maps into an even larger uncertainty in volume and thus density. The substantial collecting area of the Atacama Large Millimeter Array allows significantly more precise measurements of thermal emission from outer solarmore » system objects and could potentially greatly improve the density measurements. Here we use new thermal observations of four objects with satellites to explore the improvements possible with millimeter data. We find that effects due to effective emissivity at millimeter wavelengths make it difficult to use the millimeter data directly to find diameters and thus volumes for these bodies. In addition, we find that when including the effects of model uncertainty, the true uncertainties on the sizes of outer solar system objects measured with radiometry are likely larger than those previously published. Substantial improvement in object sizes will likely require precise occultation measurements.« less

Innovative Design and Performance Evaluation of Bionic Imprinting Toothed Wheel

PubMed Central

Wang, Xiaoyang; Tong, Jin; Stephen, Carr

2018-01-01

A highly efficient soil-burrowing dung beetle possesses an intricate outer contour curve on its foreleg end-tooth. This study was carried out based on evidence that this special outer contour curve has the potential of reducing soil penetration resistance and could enhance soil-burrowing efficiency. A toothed wheel is a typical agricultural implement for soil imprinting, to increase its working efficiency; the approach of the bionic geometrical structure was utilized to optimize the innovative shape of imprinting toothed wheel. Characteristics in the dung beetle's foreleg end-tooth were extracted and studied by the edge detection technique. Then, this special outer contour curve was modeled by a nine-order polynomial function and used for the innovative design of imprinting the tooth's cutting edge. Both the conventional and bionic teeth were manufactured, and traction tests in a soil bin were conducted. Taking required draft force and volume of imprinted microbasin as the evaluating indexes, operating efficiency and quality of different toothed wheels were compared and investigated. Results indicate that compared with the conventional toothed wheel, a bionic toothed wheel possesses a better forward resistance reduction property against soil and, meanwhile, can enhance the quality of soil imprinting by increasing the volume of the created micro-basin. PMID:29515651

Earth's Outer Core Properties Estimated Using Bayesian Inversion of Normal Mode Eigenfrequencies

NASA Astrophysics Data System (ADS)

Irving, J. C. E.; Cottaar, S.; Lekic, V.

2016-12-01

The outer core is arguably Earth's most dynamic region, and consists of an iron-nickel liquid with an unknown combination of lighter alloying elements. Frequencies of Earth's normal modes provide the strongest constraints on the radial profiles of compressional wavespeed, VΦ, and density, ρ, in the outer core. Recent great earthquakes have yielded new normal mode measurements; however, mineral physics experiments and calculations are often compared to the Preliminary reference Earth model (PREM), which is 35 years old and does not provide uncertainties. Here we investigate the thermo-elastic properties of the outer core using Earth's free oscillations and a Bayesian framework. To estimate radial structure of the outer core and its uncertainties, we choose to exploit recent datasets of normal mode centre frequencies. Under the self-coupling approximation, centre frequencies are unaffected by lateral heterogeneities in the Earth, for example in the mantle. Normal modes are sensitive to both VΦ and ρ in the outer core, with each mode's specific sensitivity depending on its eigenfunctions. We include a priori bounds on outer core models that ensure compatibility with measurements of mass and moment of inertia. We use Bayesian Monte Carlo Markov Chain techniques to explore different choices in parameterizing the outer core, each of which represents different a priori constraints. We test how results vary (1) assuming a smooth polynomial parametrization, (2) allowing for structure close to the outer core's boundaries, (3) assuming an Equation-of-State and adiabaticity and inverting directly for thermo-elastic parameters. In the second approach we recognize that the outer core may have distinct regions close to the core-mantle and inner core boundaries and investigate models which parameterize the well mixed outer core separately from these two layers. In the last approach we seek to map the uncertainties directly into thermo-elastic parameters including the bulk modulus, its pressure derivative, and molar mass and volume, with particular attention paid to the (inherent) trade-offs between the different coefficients. We discuss our results in terms of added uncertainty to the light element composition of the outer core and the potential existence of anomalous structure near the outer core's boundaries.

Assessment of fluid distribution and flow properties in two phase fluid flow using X-ray CT technology

NASA Astrophysics Data System (ADS)

Jiang, Lanlan; Wu, Bohao; Li, Xingbo; Wang, Sijia; Wang, Dayong; Zhou, Xinhuan; Zhang, Yi

2018-04-01

To study on microscale distribution of CO2 and brine during two-phase flow is crucial for understanding the trapping mechanisms of CO2 storage. In this study, CO2-brine flow experiments in porous media were conducted using X-ray computed tomography. The porous media were packed with glass beads. The pore structure (porosity/tortuosity) and flow properties at different flow rates and flow fractions were investigated. The results showed that porosity of the packed beads differed at different position as a result of heterogeneity. The CO2 saturation is higher at low injection flow rates and high CO2 fractions. CO2 distribution at the pore scale was also visualized. ∅ Porosity of porous media CT brine_ sat grey value of sample saturated with brine CT dry grey value of sample saturated with air CT brine grey value of pure brine CT air grey value of pure air CT flow grey values of sample with two fluids occupying the pore space {CT}_{CO_2_ sat} grey value of sample saturated with CO2 {f}_{CO_2}({S}_{CO_2}) CO2 fraction {q}_{CO_2} the volume flow rate for CO2 q brine the volume flow rate for brine L Thickness of the porous media, mm L e a bundle of capillaries of equal length, mm τ Tortuosity, calculated from L e / L.

EXPERIMENTAL INVESTIGATION OF RELATIVE PERMEABILITY UPSCALING FROM THE MICRO-SCALE TO THE MACRO-SCALE

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

Laura J. Pyrak-Nolte; Ping Yu; JiangTao Cheng

2002-12-01

The principal challenge of upscaling techniques for multi-phase fluid dynamics in porous media is to determine which properties on the micro-scale can be used to predict macroscopic flow and spatial distribution of phases at core- and field-scales. The most notable outcome of recent theories is the identification of interfacial areas per volume for multiple phases as a fundamental parameter that determines much of the multi-phase properties of the porous medium. A formal program of experimental research was begun to directly test upscaling theories in fluid flow through porous media by comparing measurements of relative permeability and capillary-saturation with measurements ofmore » interfacial area per volume. During this reporting period, we have shown experimentally that the coherence detection can be performed in a borescope. The measurement of interfacial area per volume (IAV), capillary pressure and saturation in two dimensional micro-models structures has shown the existence of a unique relationship among these hydraulic parameters for different pore geometry. The measurement of interfacial area per volume on a three-dimensional natural sample, i.e., sandstone, is essentially completed for imbibition conditions.« less

Using Neutron Radiography to Quantify Water Transport and the Degree of Saturation in Entrained Air Cement Based Mortar

NASA Astrophysics Data System (ADS)

Lucero, Catherine L.; Bentz, Dale P.; Hussey, Daniel S.; Jacobson, David L.; Weiss, W. Jason

Air entrainment is commonly added to concrete to help in reducing the potential for freeze thaw damage. It is hypothesized that the entrained air voids remain unsaturated or partially saturated long after the smaller pores fill with water. Small gel and capillary pores in the cement matrix fill quickly on exposure to water, but larger pores (entrapped and entrained air voids) require longer times or other methods to achieve saturation. As such, it is important to quantitatively determine the water content and degree of saturation in air entrained cementitious materials. In order to further investigate properties of cement-based mortar, a model based on Beer's Law has been developed to interpret neutron radiographs. This model is a powerful tool for analyzing images acquired from neutron radiography. A mortar with a known volume of aggregate, water to cement ratio and degree of hydration can be imaged and the degree of saturation can be estimated.

Hydrate morphology: Physical properties of sands with patchy hydrate saturation

USGS Publications Warehouse

Dai, S.; Santamarina, J.C.; Waite, William F.; Kneafsey, T.J.

2012-01-01

The physical properties of gas hydrate-bearing sediments depend on the volume fraction and spatial distribution of the hydrate phase. The host sediment grain size and the state of effective stress determine the hydrate morphology in sediments; this information can be used to significantly constrain estimates of the physical properties of hydrate-bearing sediments, including the coarse-grained sands subjected to high effective stress that are of interest as potential energy resources. Reported data and physical analyses suggest hydrate-bearing sands contain a heterogeneous, patchy hydrate distribution, whereby zones with 100% pore-space hydrate saturation are embedded in hydrate-free sand. Accounting for patchy rather than homogeneous hydrate distribution yields more tightly constrained estimates of physical properties in hydrate-bearing sands and captures observed physical-property dependencies on hydrate saturation. For example, numerical modeling results of sands with patchy saturation agree with experimental observation, showing a transition in stiffness starting near the series bound at low hydrate saturations but moving toward the parallel bound at high hydrate saturations. The hydrate-patch size itself impacts the physical properties of hydrate-bearing sediments; for example, at constant hydrate saturation, we find that conductivity (electrical, hydraulic and thermal) increases as the number of hydrate-saturated patches increases. This increase reflects the larger number of conductive flow paths that exist in specimens with many small hydrate-saturated patches in comparison to specimens in which a few large hydrate saturated patches can block flow over a significant cross-section of the specimen.

Multispectral scanner system for ERTS: Four band scanner system. Volume 2: Engineering model panoramic pictures and engineering tests

NASA Technical Reports Server (NTRS)

1972-01-01

This document is Volume 2 of three volumes of the Final Report for the four band Multispectral Scanner System (MSS). The results are contained of an analysis of pictures of actual outdoor scenes imaged by the engineering model MSS for spectral response, resolution, noise, and video correction. Also included are the results of engineering tests on the MSS for reflectance and saturation from clouds. Finally, two panoramic pictures of Yosemite National Park are provided.

Space industrialization. Volume 4: Appendices

NASA Technical Reports Server (NTRS)

1978-01-01

Program development and analysis and recommendations for NASA activities are discussed. The impact of international space law on future use of outer space is examined in the light of applicable international agreements. Recommendations for actions designed to facilitate space industralization are also proposed.

Line active hybrid lipids determine domain size in phase separation of saturated and unsaturated lipids.

PubMed

Brewster, Robert; Safran, Samuel A

2010-03-17

A simple model of the line activity of a hybrid lipid (e.g., POPC) with one fully saturated chain and one partially unsaturated chain demonstrates that these lipids preferentially pack at curved interfaces between phase-separated saturated and unsaturated domains. We predict that the domain sizes typically range from tens to hundreds of nm, depending on molecular interactions and parameters such as molecular volume and area per headgroup in the bulk fluid phase. The role of cholesterol is taken into account by an effective change in the headgroup areas and the domain sizes are predicted to increase with cholesterol concentration. Copyright 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Geographic Variations and Time Trends in Cancer Treatments in Taiwan.

PubMed

Hsu, Jason C; Chang, Sheng-Mao; Lu, Christine Y

2017-08-02

Targeted therapies have become important treatment options for cancer care in many countries. This study aimed to examine recent trends in utilization of antineoplastic drugs, particularly the use of targeted therapies for treatment of cancer, by geographic region in Taiwan (northern, midwestern, southern, and eastern regions and the outer islands). This was a retrospective observational study of antineoplastic agents using 2009-2012 quarterly claims data from Taiwan's National Health Insurance Research Database. Yearly market shares by prescription volume and costs for targeted therapies among total antineoplastic agents by region were estimated. We used multivariate regression model and ANOVA to examine variations in utilization of targeted therapies between geographic regions and used ARIMA models to estimate longitudinal trends. Population-adjusted use and costs of antineoplastic drugs (including targeted therapies) were highest in the southern region of Taiwan and lowest in the outer islands. We found a 4-fold difference in use of antineoplastic drugs and a 49-fold difference in use of targeted therapies between regions if the outer islands were included. There were minimal differences in use of antineoplastic drugs between other regions with about a 2-fold difference in use of targeted therapies. Without considering the outer islands, the market share by prescription volume and costs of targeted therapies increased almost 2-fold (1.84-1.90) and 1.5-fold (1.26-1.61) respectively between 2009 and 2012. Furthermore, region was not significantly associated with use of antineoplastic agents or use of targeted therapies after adjusting for confounders. Region was associated with costs of antineoplastic agents but it was not associated with costs of targeted therapies after confounding adjustments. Use of antineoplastic drugs overall and use of targeted therapies for treatment of cancer varied somewhat between regions in Taiwan; use was notably low in the outer islands. Strategies might be needed to ensure access to cancer care in each region as economic burden of cancer care increase due to growing use of targeted therapies.

Spatial and temporal skin blood volume and saturation estimation using a multispectral snapshot imaging camera

NASA Astrophysics Data System (ADS)

Ewerlöf, Maria; Larsson, Marcus; Salerud, E. Göran

2017-02-01

Hyperspectral imaging (HSI) can estimate the spatial distribution of skin blood oxygenation, using visible to near-infrared light. HSI oximeters often use a liquid-crystal tunable filter, an acousto-optic tunable filter or mechanically adjustable filter wheels, which has too long response/switching times to monitor tissue hemodynamics. This work aims to evaluate a multispectral snapshot imaging system to estimate skin blood volume and oxygen saturation with high temporal and spatial resolution. We use a snapshot imager, the xiSpec camera (MQ022HG-IM-SM4X4-VIS, XIMEA), having 16 wavelength-specific Fabry-Perot filters overlaid on the custom CMOS-chip. The spectral distribution of the bands is however substantially overlapping, which needs to be taken into account for an accurate analysis. An inverse Monte Carlo analysis is performed using a two-layered skin tissue model, defined by epidermal thickness, haemoglobin concentration and oxygen saturation, melanin concentration and spectrally dependent reduced-scattering coefficient, all parameters relevant for human skin. The analysis takes into account the spectral detector response of the xiSpec camera. At each spatial location in the field-of-view, we compare the simulated output to the detected diffusively backscattered spectra to find the best fit. The imager is evaluated for spatial and temporal variations during arterial and venous occlusion protocols applied to the forearm. Estimated blood volume changes and oxygenation maps at 512x272 pixels show values that are comparable to reference measurements performed in contact with the skin tissue. We conclude that the snapshot xiSpec camera, paired with an inverse Monte Carlo algorithm, permits us to use this sensor for spatial and temporal measurement of varying physiological parameters, such as skin tissue blood volume and oxygenation.

Probing the water distribution in porous model sands with two immiscible fluids: A nuclear magnetic resonance micro-imaging study

NASA Astrophysics Data System (ADS)

Lee, Bum Han; Lee, Sung Keun

2017-10-01

The effect of the structural heterogeneity of porous networks on the water distribution in porous media, initially saturated with immiscible fluid followed by increasing durations of water injection, remains one of the important problems in hydrology. The relationship among convergence rates (i.e., the rate of fluid saturation with varying injection time) and the macroscopic properties and structural parameters of porous media have been anticipated. Here, we used nuclear magnetic resonance (NMR) micro-imaging to obtain images (down to ∼50 μm resolution) of the distribution of water injected for varying durations into porous networks that were initially saturated with silicone oil. We then established the relationships among the convergence rates, structural parameters, and transport properties of porous networks. The volume fraction of the water phase increases as the water injection duration increases. The 3D images of the water distributions for silica gel samples are similar to those of the glass bead samples. The changes in water saturation (and the accompanying removal of silicone oil) and the variations in the volume fraction, specific surface area, and cube-counting fractal dimension of the water phase fit well with the single-exponential recovery function { f (t) = a [ 1 -exp (- λt) ] } . The asymptotic values (a, i.e., saturated value) of the properties of the volume fraction, specific surface area, and cube-counting fractal dimension of the glass bead samples were greater than those for the silica gel samples primarily because of the intrinsic differences in the porous networks and local distribution of the pore size and connectivity. The convergence rates of all of the properties are inversely proportional to the entropy length and permeability. Despite limitations of the current study, such as insufficient resolution and uncertainty for the estimated parameters due to sparsely selected short injection times, the observed trends highlight the first analyses of the cube-counting fractal dimension (and other structural properties) and convergence rates in porous networks consisting of two fluid components. These results indicate that the convergence rates correlate with the geometric factor that characterizes the porous networks and transport property of the porous networks.

Quiescence near the X-point of MAST measured by high speed visible imaging

NASA Astrophysics Data System (ADS)

Walkden, N. R.; Harrison, J.; Silburn, S. A.; Farley, T.; Henderson, S. S.; Kirk, A.; Militello, F.; Thornton, A.; The MAST Team

2017-12-01

Using high speed imaging of the divertor volume, the region close to the X-point in MAST is shown to be quiescent. This is confirmed by three different analysis techniques and the quiescent X-point region (QXR) spans from the separatrix to the \\psiN = 1.02 flux surface. Local reductions to the atomic density and effects associated with the camera viewing geometry are ruled out as causes of the QXR, leaving quiescence in the local plasma conditions as being the most likely cause. The QXR is found to be ubiquitous across a significant operational space in MAST including L-mode and H-mode discharges across maximal ranges of 9.8×1019~m-2 in line integrated density, 0.36 MA in plasma current, 0.11 T in toroidal magnetic field and 3.2 MW in NBI power. When mapped to the divertor target the QXR occupies approximately an e-folding length of the heat-flux profile, containing  ∼60% of the total heat flux to the target, and also shows a tendency towards higher frequency shorter lived fluctuations in the ion-saturation current. This is consistent with short-lived divertor localised filamentary structures observed further down the outer divertor leg in the camera images, and suggests a complex multi-region picture of filamentary transport in the divertor.

Inherently-Forced Tensile Strain in Nanodiamond-Derived Onion-like Carbon: Consequences in Defect-Induced Electrochemical Activation

PubMed Central

Ko, Young-Jin; Cho, Jung-Min; Kim, Inho; Jeong, Doo Seok; Lee, Kyeong-Seok; Park, Jong-Keuk; Baik, Young-Joon; Choi, Heon-Jin; Lee, Seung-Cheol; Lee, Wook-Seong

2016-01-01

We analyzed the nanodiamond-derived onion-like carbon (OLC) as function of synthesis temperature (1000~1400 °C), by high-resolution electron microscopy, electron energy loss spectroscopy, visible-Raman spectroscopy, ultraviolet photoemission spectroscopy, impedance spectroscopy, cyclic voltammetry and differential pulse voltammetry. The temperature dependences of the obtained properties (averaged particle size, tensile strain, defect density, density of states, electron transfer kinetics, and electrochemical oxidation current) unanimously coincided: they initially increased and saturated at 1200 °C. It was attributed to the inherent tensile strains arising from (1) the volume expansion associated with the layer-wise diamond-to-graphite transformation of the core, which caused forced dilation of the outer shells during their thermal synthesis; (2) the extreme curvature of the shells. The former origin was dominant over the latter at the outermost shell, of which the relevant evolution in defect density, DOS and electron transfer kinetics determined the electrochemical performances. In detection of dopamine (DA), uric acid (UA) and ascorbic acid (AA) using the OLC as electrode, their oxidation peak currents were enhanced by factors of 15~60 with annealing temperature. Their limit of detection and the linear range of detection, in the post-treatment-free condition, were as excellent as those of the nano-carbon electrodes post-treated by Pt-decoration, N-doping, plasma, or polymer. PMID:27032957

Planetary/DOD entry technology flight experiments. Volume 2: Planetary entry flight experiments

NASA Technical Reports Server (NTRS)

Christensen, H. E.; Krieger, R. J.; Mcneilly, W. R.; Vetter, H. C.

1976-01-01

The technical feasibility of launching a high speed, earth entry vehicle from the space shuttle to advance technology for the exploration of the outer planets' atmospheres was established. Disciplines of thermodynamics, orbital mechanics, aerodynamics propulsion, structures, design, electronics and system integration focused on the goal of producing outer planet environments on a probe shaped vehicle during an earth entry. Major aspects of analysis and vehicle design studied include: planetary environments, earth entry environment capability, mission maneuvers, capabilities of shuttle upper stages, a comparison of earth entry planetary environments, experiment design and vehicle design.

Publications - GMC 192 | Alaska Division of Geological & Geophysical

Science.gov Websites

DGGS GMC 192 Publication Details Title: Compressive and shear wave velocity measurements as brine , Compressive and shear wave velocity measurements as brine-saturated measurements (volume 1) and as soltrol

Predicting performance of polymer-bonded Terfenol-D composites under different magnetic fields

NASA Astrophysics Data System (ADS)

Guan, Xinchun; Dong, Xufeng; Ou, Jinping

2009-09-01

Considering demagnetization effect, the model used to calculate the magnetostriction of the single particle under the applied field is first created. Based on Eshelby equivalent inclusion and Mori-Tanaka method, the approach to calculate the average magnetostriction of the composites under any applied field, as well as the saturation, is studied by treating the magnetostriction particulate as an eigenstrain. The results calculated by the approach indicate that saturation magnetostriction of magnetostrictive composites increases with an increase of particle aspect and particle volume fraction, and a decrease of Young's modulus of the matrix. The influence of an applied field on magnetostriction of the composites becomes more significant with larger particle volume fraction or particle aspect. Experiments were done to verify the effectiveness of the model, the results of which indicate that the model only can provide approximate results.

Headspace concentrations of explosive vapors in containers designed for canine testing and training: theory, experiment, and canine trials.

PubMed

Lotspeich, Erica; Kitts, Kelley; Goodpaster, John

2012-07-10

It is a common misconception that the amount of explosive is the chief contributor to the quantity of vapor that is available to trained canines. In fact, this quantity (known as odor availability) depends not only on the amount of explosive material, but also the container volume, explosive vapor pressure and temperature. In order to better understand odor availability, headspace experiments were conducted and the results were compared to theory. The vapor-phase concentrations of three liquid explosives (nitromethane, nitroethane and nitropropane) were predicted using the Ideal Gas Law for containers of various volumes that are in use for canine testing. These predictions were verified through experiments that varied the amount of sample, the container size, and the temperature. These results demonstrated that the amount of sample that is needed to saturate different sized containers is small, predictable and agrees well with theory. In general, and as expected, once the headspace of a container is saturated, any subsequent increase in sample volume will not result in the release of more vapors. The ability of canines to recognize and alert to differing amounts of nitromethane has also been studied. In particular, it was found that the response of trained canines is independent of the amount of nitromethane present, provided it is a sufficient quantity to saturate the container in which it is held. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Strain localization in usnaturated soils with large deformation

NASA Astrophysics Data System (ADS)

Song, X.; Borja, R. I.

2014-12-01

Strain localization is a ubiquitous feature of granular materials undergoing nonhomogeneous deformation. In unsaturated porous media, how the localized deformation band is formed depends crucially on the degree of saturation, since fluid in the pores of a solid imposes a volume constraint on the deformation of the solid. When fluid flow is involved, the inception of the localized deformation band also depends on the heterogeneity of a material, which is quantified in terms of the spatial variation of density, the degree of saturation, and matric suction. We present a mathematical framework for coupled solid-deformation/fluid-diffusion in unsaturated porous media that takes into account material and geometric nonlinearities [1, 2]. The framework relies on the continuum principle of thermodynamics to identify an effective, or constitutive, stress for the solid matrix, and a water retention law that highlights the interdependence of degree of saturation, suction, and porosity of the material. We discuss the role of heterogeneity, quantified either deterministically or stochastically, on the development of a persistent shear band. We derive bifurcation conditions [3] governing the initiation of such a shear band. This research is inspired by current testing techniques that allow nondestructive and non-invasive measurement of density and the degree of saturation through high-resolution imaging [4]. The numerical simulations under plane strain condition demonstrate that the bifurcation not only manifests itself on the loading response curve and but also in the space of the degree of saturation, specific volume and suction stress. References[1] Song X, Borja RI, Mathematical framework for unsaturated flow in the finite deformation range. Int. J. Numer. Meth. Engng 2014; 97: 658-686. [2] Song X, Borja RI, Finite deformation and fluid flow in unsaturated soils with random heterogeneity. Vadose Zone Journal 2014; doi:10.2136/vzj2013.07.0131. [3] Song X, Borja RI, Instability and bifurcation in partially saturated porous media. 2014. to be submitted. [4] Song X, Strain localization in unsaturated porous media. 2014. Ph.D. Dissertation, Stanford University, California.

The Location of the Cochlear Amplifier: Spatial Representation of a Single Tone on the Guinea Pig Basilar Membrane

NASA Astrophysics Data System (ADS)

Russell, I. J.; Nilsen, K. E.

1997-03-01

Acoustic stimulation vibrates the cochlear basilar membrane, initiating a wave of displacement that travels toward the apex and reaches a peak over a restricted region according to the stimulus frequency. In this characteristic frequency region, a tone at the characteristic frequency maximally excites the sensory hair cells of the organ of Corti, which transduce it into electrical signals to produce maximum activity in the auditory nerve. Saturating, nonlinear, feedback from the motile outer hair cells is thought to provide electromechanical amplification of the travelling wave. However, neither the location nor the extent of the source of amplification, in relation to the characteristic frequency, are known. We have used a laser--diode interferometer to measure in vivo the distribution along the basilar membrane of nonlinear, saturating vibrations to 15 kHz tones. We estimate that the site of amplification for the 15 kHz region is restricted to a 1.25 mm length of basilar membrane centered on the 15 kHz place.

Estimation of CO2 saturation during both CO2 drainage and imbibition processes based on both seismic velocity and electrical resistivity measurements

NASA Astrophysics Data System (ADS)

Kim, Jongwook; Nam, Myung Jin; Matsuoka, Toshifumi

2013-10-01

In order to monitor injected carbon dioxide (CO2), simultaneous measurements of seismic velocity and electrical resistivity are employed during the drainage (CO2 injection) and imbibition (water injection) processes of a Berea sandstone. Supercritical CO2 (10 MPa at 40 ºC) was injected into a water-saturated Berea sandstone in the drainage stage and monitored via simultaneous measurements. After the injection of supercritical CO2, fresh distilled water was injected into the CO2-injected sandstone during the imbibition stage. Electrical resistivity and P-wave velocity measurements acquired during the drainage and imbibition stages were employed to evaluate CO2 saturations (SCO2) based on the resistivity index and the Gassmann fluid-substitution equations, respectively. Comparing estimated values for SCO2 saturation against those from volume-derived SCO2, based on analysis on injected and drained fluid volumes in the drainage process, we conclude that Gassmann-Brie and resistivity index are suitable for the evaluation based on P-wave velocity and electrical resistivity, respectively. Rt-based estimation properly tracks the variation in SCO2 even when SCO2 is large (>0.15), while Vp-based estimation is sensitive to the variation in SCO2 when SCO2 is small (<0.1). Employing the Gassmann-Brie and resistivity index, estimation of variation in SCO2 based on the simultaneous measurements provides the upper and lower bounds of SCO2 even when SCO2 is large (>0.1), while properly estimating SCO2 when SCO2 is small (<0.1). Monitoring the CO2 imbibition process confirms residual CO2 saturation within the sample.

X-ray Computed Tomography and Pore Network Modeling to Assess the Impact of Biochar on Saturated Hydraulic Conductivity of Stormwater Infiltration Media

NASA Astrophysics Data System (ADS)

Imhoff, P. T.; Nakhli, S. A. A.; Mills, G.; Yudi, Y.; Abera, K.; Williams, R.; Manahiloh, K. N.; Willson, C. S.

2017-12-01

Biochar has been proposed as an amendment to stormwater infiltration media to enhance pollutant capture (metals, organics) or transformation (e.g., nitrate). Because stormwater media must maintain sufficient infiltration capacity, it is critical that biochar amendment not reduce saturated hydraulic conductivity. We present experimental measurements of saturated hydraulic conductivity for mixtures of wood biochar, sieved to various size fractions, and uniform sands or bioretention media (mixtures of sand, clay, and sawdust). While the influence of biochar on the inter particle pore volume of the mixtures explained most changes in hydraulic conductivity, for mixtures containing large biochar particles results were unexpected. For example, while large biochar particles (2 - 4.75 mm) increased inter particle porosity from 0.35 to 0.48 for a sand/biochar mixture, hydraulic conductivity decreased from 820 ± 90 cm/h to 323 ± 2 cm/h. To understand this and other unusual data, biochar was doped with 3% CsCl, mixed with uniform sand using different packing techniques, and analyzed with X-ray computed tomography to assess biochar distribution and pore structure. Depending on packing technique, biochar particles were either segregated or uniformly mixed, which influenced pore structure. Biochar content and inter particle pore volume determined from X-ray images were in excellent agreement with experimental data (< 5% difference). Grain-based algorithms were then used to generate physically-representative pore networks, and single-phase permeability models were employed to estimate saturated hydraulic conductivity of sand and biochar-amended sand packings for specimens prepared with different packing techniques. Results from these analyses will be presented and compared with experimental measurements to elucidate the mechanisms by which large biochar particles alter the saturated hydraulic conductivity of engineered media.

Design and Operating Characteristics of High-Speed, Small-Bore, Angular-Contact Ball Bearings

NASA Technical Reports Server (NTRS)

Pinel, Stanley I.; Signer, Hans R.; Zaretsky, Erwin V.

1998-01-01

The computer program SHABERTH was used to analyze 35-mm-bore, angular-contact ball bearings designed and manufactured for high-speed turbomachinery applications. Parametric tests of the bearings were conducted on a high-speed, high-temperature bearing tester and were compared with the computer predictions. Four bearing and cage designs were studied. The bearings were lubricated either by jet lubrication or through the split inner ring with and without outer-ring cooling. The predicted bearing life decreased with increasing speed because of increased operating contact stresses caused by changes in contact angle and centrifugal load. For thrust loads only, the difference in calculated life for the 24 deg. and 30 deg. contact-angle bearings was insignificant. However, for combined loading, the 24 deg. contact-angle bearing gave longer life. For split-inner-ring bearings, optimal operating conditions were obtained with a 24 deg. contact angle and an inner-ring, land-guided cage, using outer-ring cooling in conjunction with low lubricant flow rates. Lower temperature and power losses were obtained with a single-outer-ring, land-guided cage for the 24 deg. contact-angle bearing having a relieved inner ring and partially relieved outer ring. Inner-ring temperatures were independent of lubrication mode and cage design. In comparison with measured values, reasonably good engineering correlation was obtained using the computer program SHABERTH for predicted bearing power loss and for inner- and outer-ring temperatures. The Parker formula for XCAV (used in SHABERTH, a measure of oil volume in the bearing cavity) may need to be refined to reflect bearing lubrication mode, cage design, and location of cage-controlling land.

Simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in humans and other animal models using a single light source

NASA Astrophysics Data System (ADS)

Dent, Paul; Tun, Sai Han; Fillioe, Seth; Deng, Bin; Satalin, Josh; Nieman, Gary; Wilcox, Kailyn; Searles, Quinn; Narsipur, Sri; Peterson, Charles M.; Goodisman, Jerry; Mostrom, James; Steinmann, Richard; Chaiken, J.

2018-02-01

We previously reported a new algorithm "PV[O]H" for continuous, noninvasive, in vivo monitoring of hematocrit changes in blood and have since shown its utility for monitoring in humans during 1) hemodialysis, 2) orthostatic perturbations and 3) during blood loss and fluid replacement in a rat model. We now show that the algorithm is sensitive to changes in hemoglobin oxygen saturation. We document the phenomenology of the effect and explain the effect using new results obtained from humans and rat models. The oxygen sensitivity derives from the differential absorption of autofluorescence originating in the static tissues by oxy and deoxy hemoglobin. Using this approach we show how to perform simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in mammals using a single light source. We suspect that monitoring of changes in this suite of vital signs can be provided with improved time response, sensitivity and precision compared to existing methodologies. Initial results also offer a more detailed glimpse into the systemic oxygen transport in the circulatory system of humans.

Ares I Reaction Control System Propellant Feedline Decontamination Modeling

NASA Technical Reports Server (NTRS)

Pasch, James J.

2010-01-01

The objective of the work presented here is to quantify the effects of purge gas temperature, pressure, and mass flow rate on Hydrazine (Hz) decontamination rates of the Ares I Roll Control System and Reaction Control System. A survey of experts in this field revealed the absence of any decontamination rate prediction models. Three basic decontamination methods were identified for analysis and modeling. These include low pressure eduction, high flow rate purge, and pulse purge. For each method, an approach to predict the Hz mass transfer rate, as a function of system pressure, temperature, and purge gas mass flow rate, is developed based on the applicable physics. The models show that low pressure eduction is two orders of magnitude more effective than the high velocity purge, which in turn is two orders of magnitude more effective than the pure diffusion component of pulse purging of deadheads. Eduction subjects the system to low pressure conditions that promote the extraction of Hz vapors. At 120 F, Hz is saturated at approximately 1 psia. At lower pressures and 120 F, Hz will boil, which is an extremely efficient means to remove liquid Hz. The Hz boiling rate is predicted by equating the rate at which energy is added to the saturated liquid Hz through heaters at the tube outer wall with the energy removed from the liquid through evaporation. Boil-off fluxes were predicted by iterating through the range of local pressures with limits set by the minimum allowed pressure of 0.2 psia and maximum allowed wall temperature of 120 F established by the heaters, which gives a saturation pressure of approximately 1.0 psia. Figure 1 shows the resulting boil-off fluxes as a function of local eduction pressure. As depicted in figure 1, the flux is a strong inverse function of eduction pressure, and that minimizing the eduction pressure maximizes the boil-off flux. Also, higher outer wall temperatures lead to higher boil-off fluxes and allow for boil-off over a greater range of eduction pressures.

Liquid level, void fraction, and superheated steam sensor for nuclear reactor cores

DOEpatents

Tokarz, Richard D.

1983-01-01

An apparatus for detecting nominal phase conditions of coolant in a reactor vessel comprising one or more lengths of tubing each leading from a location being monitored to a closed outer end exterior of the vessel. Temperature is sensed at the open end of each length of tubing. Pressure within the tubing is also sensed. Both measurements are directed to an analyzer which compares the measured temperature to the known saturated temperature of the coolant at the measured pressure. In this manner, the nominal phase conditions of the coolant are constantly monitored.

Saturation-dependent solute dispersivity in porous media: Pore-scale processes

NASA Astrophysics Data System (ADS)

Raoof, A.; Hassanizadeh, S. M.

2013-04-01

It is known that in variably saturated porous media, dispersion coefficient depends on Darcy velocity and water saturation. In one-dimensional flow, it is commonly assumed that the dispersion coefficient is a linear function of velocity. The coefficient of proportionality, called the dispersivity, is considered to depend on saturation. However, there is not much known about its dependence on saturation. In this study, we investigate, using a pore network model, how the longitudinal dispersivity varies nonlinearly with saturation. We schematize the porous medium as a network of pore bodies and pore throats with finite volumes. The pore space is modeled using the multidirectional pore-network concept, which allows for a distribution of pore coordination numbers. This topological property together with the distribution of pore sizes are used to mimic the microstructure of real porous media. The dispersivity is calculated by solving the mass balance equations for solute concentration in all network elements and averaging the concentrations over a large number of pores. We have introduced a new formulation of solute transport within pore space, where we account for different compartments of residual water within drained pores. This formulation makes it possible to capture the effect of limited mixing due to partial filling of the pores under variably saturated conditions. We found that dispersivity increases with the decrease in saturation, it reaches a maximum value, and then decreases with further decrease in saturation. To show the capability of our formulation to properly capture the effect of saturation on solute dispersion, we applied it to model the results of a reported experimental study.

An Estimate of Recoverable Heavy Oil Resources of the Orinoco Oil Belt, Venezuela

USGS Publications Warehouse

Schenk, Christopher J.; Cook, Troy A.; Charpentier, Ronald R.; Pollastro, Richard M.; Klett, Timothy R.; Tennyson, Marilyn E.; Kirschbaum, Mark A.; Brownfield, Michael E.; Pitman, Janet K.

2009-01-01

The Orinoco Oil Belt Assessment Unit of the La Luna-Quercual Total Petroleum System encompasses approximately 50,000 km2 of the East Venezuela Basin Province that is underlain by more than 1 trillion barrels of heavy oil-in-place. As part of a program directed at estimating the technically recoverable oil and gas resources of priority petroleum basins worldwide, the U.S. Geological Survey estimated the recoverable oil resources of the Orinoco Oil Belt Assessment Unit. This estimate relied mainly on published geologic and engineering data for reservoirs (net oil-saturated sandstone thickness and extent), petrophysical properties (porosity, water saturation, and formation volume factors), recovery factors determined by pilot projects, and estimates of volumes of oil-in-place. The U.S. Geological Survey estimated a mean volume of 513 billion barrels of technically recoverable heavy oil in the Orinoco Oil Belt Assessment Unit of the East Venezuela Basin Province; the range is 380 to 652 billion barrels. The Orinoco Oil Belt Assessment Unit thus contains one of the largest recoverable oil accumulations in the world.

Solvothermal Synthesis of Hierarchical Colloidal Nanocrystal Assemblies of ZnFe₂O₄ and Their Application in Water Treatment.

PubMed

Guo, Peizhi; Lv, Meng; Han, Guangting; Wen, Changna; Wang, Qianbin; Li, Hongliang; Zhao, Xiusong

2016-09-29

Hierarchical colloidal nanocrystal assemblies (CNAs) of ZnFe₂O₄ have been synthesized controllably by a solvothermal method. Hollow ZnFe₂O₄ spheres can be formed with the volume ratios of ethylene glycol to ethanol of 1:4 in the starting systems, while solid ZnFe₂O₄ CNAs are obtained by adjusting the volume proportion of ethylene glycol to ethanol from 1:2 to 2:1. Magnetometric measurement data showed that the ZnFe₂O₄ CNAs obtained with the volume ratios of 1:2 and 1:1 exhibited weak ferromagnetic behavior with high saturation magnetization values of 60.4 and 60.3 emu·g -1 , respectively. However, hollow spheres showed a saturation magnetization value of 52.0 emu·g -1 , but the highest coercivity among all the samples. It was found that hollow spheres displayed the best ability to adsorb Congo red dye among all the CNAs. The formation mechanisms of ZnFe₂O₄ CNAs, as well as the relationship between their structure, crystallite size, and properties were discussed based on the experimental results.

The jammed-to-mobile transition in frozen sand under stress

NASA Astrophysics Data System (ADS)

Durham, W. B.; Pathare, A.; Stern, L. A.; Lenferink, H. J.

2009-12-01

We conducted laboratory deformation experiments on sand-rich mixtures of sand + ice under sufficient confinement to inhibit macroscopic dilation. Dry sand packs constrained not to dilate when they are under a shearing load reach an immobile or “jammed” state, as load-supporting “force chains” of sand particles form after a small amount of strain and cannot be broken without volume expansion. Our research objective here was to find the minimum volume fraction of ice required to overcome the jammed state. The result surprised us: the required volume fraction is not a fixed number, but depends on the packing characteristics of the sand in question. Experiments were carried out in a triaxial gas deformation rig at confining pressures (60 - 200 MPa) always at least twice the level of differential stresses (11 - 50 MPa) in order to suppress dilatancy. Run temperatures were 223 - 243 K. We used two kinds of quartz sand, one well-sorted, with a maximum dry packing density (MDPD) of about 0.68 sand by volume, and the other a mixture of two sizes, having a higher MDPD of 0.75. Ice volume fraction ranged from well below saturation (where unfilled porosity necessarily remained) to slightly greater than the value of porosity at MDPD. We tested these frozen sands in compression under constant applied differential stress (creep). Strain rates were very low at these conditions, and runs took days or weeks to complete. The amount of strain required to reach the jammed state in ice-undersaturated samples was approximately 0.04, and did not show an obvious dependence on ice content. For both sands, the onset of mobility occurred at approximately 5% above the value of pore volume at MDPD. Furthermore, viscosity of mobile frozen sand near the transition point was extremely sensitive to ice fraction, which implies that at geologic strain rates, far slower than we can reach in the lab, the ice fraction at transition may lie closer to that at MDPD. Cryogenic scanning electron microscopy shows that fracturing of sand grains occurs in ice-undersaturated samples, but gradually disappears as saturation is reached. There are no fractured sand grains in deforming mobile frozen sand packs. One application of this work is to the regolith of Mars at mid-latitudes and poleward, where significant ice is expected to be present. Partially relaxed (“softened”) landforms such as craters require the presence of ice, but also suggest strengths far higher than that of ice. The extreme sensitivity of viscosity to ice content near the mobility boundary, and the near coincidence of mobility and saturation at MDPD together suggest a plausible explanation for partial landform softening on Mars that does not require a fortuitous ice content or an unrealistically brief period of saturation; namely, that the water content of the Martian regolith lies at or near saturation. If true, we can estimate the historical water content of the Martian regolith for reasonable soil densities as being between 120 and 240 global meters of water for the upper kilometer of crust. This is somewhat lower than previous estimates.

Pleistocene vertical motions of the Costa Rican outer forearc from subducting topography and a migrating fracture zone triple junction

USGS Publications Warehouse

Edwards, Joel H.; Kluesner, Jared W.; Silver, Eli A.; Bangs, Nathan L.

2018-01-01

Understanding the links between subducting slabs and upper-plate deformation is a longstanding goal in the field of tectonics. New 3D seismic sequence stratigraphy, mapped within the Costa Rica Seismogenesis Project (CRISP) seismic-reflection volume offshore southern Costa Rica, spatiotemporally constrains several Pleistocene outer forearc processes and provides clearer connections to subducting plate dynamics. Three significant shelf and/or slope erosional events at ca. 2.5–2.3 Ma, 1.95–1.78 Ma, and 1.78–1.19 Ma, each with notable differences in spatial extent, volume removed, and subsequent margin response, caused abrupt shifts in sedimentation patterns and rates. These shifts, coupled with observed deformation, suggest three primary mechanisms for Pleistocene shelf and slope vertical motions: (1) regional subaerial erosion and rapid subsidence linked to the southeastward Panama Fracture Zone triple-junction migration, with associated abrupt bathymetric variations and plate kinematic changes; (2) transient, kilometer-scale uplift and subsidence due to inferred subducting plate topography; and (3) progressive outer wedge shortening accommodated by landward- and seaward-dipping thrust faults and fold development due to the impinging Cocos Ridge. Furthermore, we find that the present-day wedge geometry (to within ∼3 km along strike) has been maintained through the Pleistocene, in contrast to modeled landward margin retreat. We also observe that deformation, i.e., extension and shortening, is decoupled from net margin subsidence. Our findings do not require basal erosion, and they suggest that the vertical motions of the Costa Rican outer forearc are not the result of a particular continuous process, but rather are a summation of plate to plate changes (e.g., passage of a fracture zone triple junction) and episodic events (e.g., subducting plate topography).

Electrical resistivity of substitutionally disordered hcp Fe-Si and Fe-Ni alloys: Chemically-induced resistivity saturation in the Earth's core

NASA Astrophysics Data System (ADS)

Gomi, Hitoshi; Hirose, Kei; Akai, Hisazumi; Fei, Yingwei

2016-10-01

The thermal conductivity of the Earth's core can be estimated from its electrical resistivity via the Wiedemann-Franz law. However, previously reported resistivity values are rather scattered, mainly due to the lack of knowledge with regard to resistivity saturation (violations of the Bloch-Grüneisen law and the Matthiessen's rule). Here we conducted high-pressure experiments and first-principles calculations in order to clarify the relationship between the resistivity saturation and the impurity resistivity of substitutional silicon in hexagonal-close-packed (hcp) iron. We measured the electrical resistivity of Fe-Si alloys (iron with 1, 2, 4, 6.5, and 9 wt.% silicon) using four-terminal method in a diamond-anvil cell up to 90 GPa at 300 K. We also computed the electronic band structure of substitutionally disordered hcp Fe-Si and Fe-Ni alloy systems by means of Korringa-Kohn-Rostoker method with coherent potential approximation (KKR-CPA). The electrical resistivity was then calculated from the Kubo-Greenwood formula. These experimental and theoretical results show excellent agreement with each other, and the first principles results show the saturation behavior at high silicon concentration. We further calculated the resistivity of Fe-Ni-Si ternary alloys and found the violation of the Matthiessen's rule as a consequence of the resistivity saturation. Such resistivity saturation has important implications for core dynamics. The saturation effect places the upper limit of the resistivity, resulting in that the total resistivity value has almost no temperature dependence. As a consequence, the core thermal conductivity has a lower bound and exhibits a linear temperature dependence. We predict the electrical resistivity at the top of the Earth's core to be 1.12 ×10-6 Ωm, which corresponds to the thermal conductivity of 87.1 W/m/K. Such high thermal conductivity suggests high isentropic heat flow, leading to young inner core age (<0.85 Gyr old) and high initial core temperature. It also strongly suppresses thermal convection in the core, which results in no convective motion in inner core and possibly thermally stratified layer in the outer core.

Paradoxes of thermodynamics of swelling equilibria of polymers in liquids and vapors.

PubMed

Davankov, Vadim A; Pastukhov, Alexander V

2011-12-29

An automatic registration of the changing size of a single spherical microbead of a cross-linked polymer was applied for studying the swelling process of the bead by the sorption of vapors and/or liquids. Many representatives of all three basic types of polymeric networks, gel-type, hypercrosslinked, and macroporous, were examined. Only the first two display large volume changes and prove suitable for following the kinetics and extent of swelling by the above dilatometric technique. The results unambiguously prove that swelling of all polymeric networks in liquids is always higher than in corresponding saturated vapors (Schroeder's paradox). The general nature of this phenomenon implies that the absolute activity of any sorbate in its liquid form is always larger than in the form of its saturated vapor. Surprisingly, gels with any solvent contents, which fall into the broad range between the vapor-equilibrated and liquid-equilibrated extreme contents, retain their volumes constant in the saturated vapor atmosphere. This paradox of a wide range of gels swollen to a different extent and, nevertheless, standing in equilibrium with saturated vapor is explained by the specificity of the network polymers, namely, that the energy of the solvent-polymer interactions is easily compensated by the energy of remaining between-chain interactions at any solvent content in the above range. Therefore, the strain-free swollen gels do not generate enhanced vapor pressure, but neither display the ability to take up more sorbate from its vapor. © 2011 American Chemical Society

Rapid and quantitative chemical exchange saturation transfer (CEST) imaging with magnetic resonance fingerprinting (MRF).

PubMed

Cohen, Ouri; Huang, Shuning; McMahon, Michael T; Rosen, Matthew S; Farrar, Christian T

2018-05-13

To develop a fast magnetic resonance fingerprinting (MRF) method for quantitative chemical exchange saturation transfer (CEST) imaging. We implemented a CEST-MRF method to quantify the chemical exchange rate and volume fraction of the N α -amine protons of L-arginine (L-Arg) phantoms and the amide and semi-solid exchangeable protons of in vivo rat brain tissue. L-Arg phantoms were made with different concentrations (25-100 mM) and pH (pH 4-6). The MRF acquisition schedule varied the saturation power randomly for 30 iterations (phantom: 0-6 μT; in vivo: 0-4 μT) with a total acquisition time of ≤2 min. The signal trajectories were pattern-matched to a large dictionary of signal trajectories simulated using the Bloch-McConnell equations for different combinations of exchange rate, exchangeable proton volume fraction, and water T 1 and T 2 relaxation times. The chemical exchange rates of the N α -amine protons of L-Arg were significantly (P < 0.0001) correlated with the rates measured with the quantitation of exchange using saturation power method. Similarly, the L-Arg concentrations determined using MRF were significantly (P < 0.0001) correlated with the known concentrations. The pH dependence of the exchange rate was well fit (R 2  = 0.9186) by a base catalyzed exchange model. The amide proton exchange rate measured in rat brain cortex (34.8 ± 11.7 Hz) was in good agreement with that measured previously with the water exchange spectroscopy method (28.6 ± 7.4 Hz). The semi-solid proton volume fraction was elevated in white (12.2 ± 1.7%) compared to gray (8.1 ± 1.1%) matter brain regions in agreement with previous magnetization transfer studies. CEST-MRF provides a method for fast, quantitative CEST imaging. © 2018 International Society for Magnetic Resonance in Medicine.

Multianode cylindrical proportional counter for high count rates

DOEpatents

Hanson, J.A.; Kopp, M.K.

1980-05-23

A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (< 60 keV) at count rates of greater than 10/sup 5/ counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

Multianode cylindrical proportional counter for high count rates

DOEpatents

Hanson, James A.; Kopp, Manfred K.

1981-01-01

A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (<60 keV) at count rates of greater than 10.sup.5 counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

Derivation of the collision probability between orbiting objects The lifetimes of Jupiter's outer moons

NASA Technical Reports Server (NTRS)

Kessler, D. J.

1981-01-01

A general form is derived for Opik's equations relating to the probability of collision between two orbiting objects to their orbital elements, and used to determine the collisional lifetime of the eight outer moons of Jupiter. The derivation is based on a concept of spatial density, or average number of objects found in a unit volume, and results in a set of equations that are easily applied to a variety of orbital collision problems. When applied to the outer satellites, which are all in irregular orbits, the equations predict a relatively long collisional lifetime for the four retrograde moons (about 270 billon years on the average) and a shorter time for the four posigrade moons (0.9 billion years). This short time is suggestive of a past collision history, and may account for the orbiting dust detected by Pioneers 10 and 11.

Turbine airfoil having near-wall cooling insert

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

Martin, Jr., Nicholas F.; Wiebe, David J.

A turbine airfoil is provided with at least one insert positioned in a cavity in an airfoil interior. The insert extends along a span-wise extent of the turbine airfoil and includes first and second opposite faces. A first near-wall cooling channel is defined between the first face and a pressure sidewall of an airfoil outer wall. A second near-wall cooling channel is defined between the second face and a suction sidewall of the airfoil outer wall. The insert is configured to occupy an inactive volume in the airfoil interior so as to displace a coolant flow in the cavity towardmore » the first and second near-wall cooling channels. A locating feature engages the insert with the outer wall for supporting the insert in position. The locating feature is configured to control flow of the coolant through the first or second near-wall cooling channel.« less

Honeywell's Compact, Wide-angle Uv-visible Imaging Sensor

NASA Technical Reports Server (NTRS)

Pledger, D.; Billing-Ross, J.

1993-01-01

Honeywell is currently developing the Earth Reference Attitude Determination System (ERADS). ERADS determines attitude by imaging the entire Earth's limb and a ring of the adjacent star field in the 2800-3000 A band of the ultraviolet. This is achieved through the use of a highly nonconventional optical system, an intensifier tube, and a mega-element CCD array. The optics image a 30 degree region in the center of the field, and an outer region typically from 128 to 148 degrees, which can be adjusted up to 180 degrees. Because of the design employed, the illumination at the outer edge of the field is only some 15 percent below that at the center, in contrast to the drastic rolloffs encountered in conventional wide-angle sensors. The outer diameter of the sensor is only 3 in; the volume and weight of the entire system, including processor, are 1000 cc and 6 kg, respectively.

Evaluation of Upland Disposal of Oakland Harbor, California, Sediment. Volume 2: Inner and Outer Harbor Sediments

DTIC Science & Technology

1993-08-01

the drop size and terminal velocities of natural rain- fall, factors which are critical in erosion and infiltration studies ( Westerdahl and Skogerboe... Westerdahl and Skogerboe 1982; Lee and Skogerboe 1984; Skogerboe et al. 1987). The WES Rainfall Simulator/ Lysimeter System proved to be an effective...Waters (Phase IIIA of -42-Foot Project); Volume 2: Appendixes," iNL-83-2, Vol 2, Battelle/Marine Science Laboratory, Sequim, WA. Westerdahl , H. E., and

Mars: Crustal pore volume, cryospheric depth, and the global occurrence of groundwater

NASA Technical Reports Server (NTRS)

Clifford, Stephen M.

1987-01-01

It is argued that most of the Martian hydrosphere resides in a porous outer layer of crust that, based on a lunar analogy, appears to extend to a depth of about 10 km. The total pore volume of this layer is sufficient to store the equivalent of a global ocean of water some 500 to 1500 m deep. Thermal modeling suggests that about 300 to 500 m of water could be stored as ice within the crust. Any excess must exist as groundwater.

Miniaturized Nanocomposite Piezoelectric Microphones for UAS Applications

DTIC Science & Technology

2012-10-22

volume fraction for three different materials: ZnO/SU-8 composite, ZnO thin film, and PZT thin film. This was computed for a microphone of outer...radius, 2 400R mμ= , and a thickness 1t mμ= . Note the significant increase in sensitivity compared to a solid ZnO or PZT film. This arises because, as...predicted range. An optimal volume fraction of 0.3 yielded a 17-fold increase in sensitivity over ZnO and a 49-fold increase over PZT . Figure 6

1998 Physical Acoustics Summer School (PASS 98). Volume III: Background Materials.

DTIC Science & Technology

1998-01-01

propagating hydrodynamic soliton ■ Shock waves, N waves, and sound eating sound ■ Acoustic Bernoulli effect ■ Acoustic levitation ■ Acoustic match ...cess. The resulting saturation values are given in the diagrams and nicely match the values given in (10). Delay reconstructions using the experimen...VOLUME 47, NUMBER 20 PHYSICAL REVIEW LETTERS 16 NOVEMBER 1981 oscillations of the driving sound field match three oscillations of the natural

Porosity of Self-Compacting Concrete (SCC) incorporating high volume fly ash

NASA Astrophysics Data System (ADS)

Kristiawan, S. A.; Sunarmasto; Murti, G. Y.

2017-02-01

Degradation of concrete could be triggered by the presence of aggressive agents from the environment into the body of concrete. The penetration of these agents is influenced by the pore characteristics of the concrete. Incorporating a pozzolanic material such as fly ash could modify the pore characteristic of the concrete. This research aims to investigate the influence of incorporating fly ash at high volume level on the porosity of Self-Compacting Concrete (SCC). Laboratory investigations were carried out following the ASTM C642 for measuring density and volume of permeable pores (voids) of the SCC with varying fly ash contents (50-70% by weight of total binder). In addition, a measurement of permeable voids by saturation method was carried out to obtain an additional volume of voids that could not be measured by the immersion and boiling method of ASTM C642. The results show that the influence of fly ash content on the porosity appears to be dependent on age of SCC. At age less than 56 d, fly ash tends to cause an increase of voids but at 90 d of age it reduces the pores. The additional pores that can be penetrated by vacuum saturation method counts about 50% of the total voids.

EXPERIMENTAL INVESTIGATION OF RELATIVE PERMEABILITY UPSCALING FROM THE MICRO-SCALE TO THE MACRO-SCALE

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

JiangTao Cheng; Ping Yu; William Headley

2001-12-01

The principal challenge of upscaling techniques for multi-phase fluid dynamics in porous media is to determine which properties on the micro-scale can be used to predict macroscopic flow and spatial distribution of phases at core- and field-scales. The most notable outcome of recent theories is the identification of interfacial areas per volume for multiple phases as a fundamental parameter that determines much of the multi-phase properties of the porous medium. A formal program of experimental research was begun to directly test upscaling theories in fluid flow through porous media by comparing measurements of relative permeability and capillary-saturation with measurements ofmore » interfacial area per volume. During this reporting period, we have shown experimentally and theoretically that the optical coherence imaging system is optimized for sandstone. The measurement of interfacial area per volume (IAV), capillary pressure and saturation in two dimensional micro-models structures that are statistically similar to real porous media has shown the existence of a unique relationship among these hydraulic parameters. The measurement of interfacial area per volume on a three-dimensional natural sample, i.e., sandstone, has the same length-scale as the values of IAV determined for the two-dimensional micro-models.« less

Saturation current and collection efficiency for ionization chambers in pulsed beams.

PubMed

DeBlois, F; Zankowski, C; Podgorsak, E B

2000-05-01

Saturation currents and collection efficiencies in ionization chambers exposed to pulsed megavoltage photon and electron beams are determined assuming a linear relationship between 1/I and 1/V in the extreme near-saturation region, with I and V the chamber current and polarizing voltage, respectively. Careful measurements of chamber current against polarizing voltage in the extreme near-saturation region reveal a current rising faster than that predicted by the linear relationship. This excess current combined with conventional "two-voltage" technique for determination of collection efficiency may result in an up to 0.7% overestimate of the saturation current for standard radiation field sizes of 10X10 cm2. The measured excess current is attributed to charge multiplication in the chamber air volume and to radiation-induced conductivity in the stem of the chamber (stem effect). These effects may be accounted for by an exponential term used in conjunction with Boag's equation for collection efficiency in pulsed beams. The semiempirical model follows the experimental data well and accounts for both the charge recombination as well as for the charge multiplication effects and the chamber stem effect.

75 FR 72761 - Production Measurement Documents Incorporated by Reference

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-26

... of crude oil, refined products, or lubricating oils. Natural gas liquids and liquid petroleum gases... standards into the regulations governing oil, gas, and sulphur operations in the Outer Continental Shelf... oil and gas production volumes. This will result in more efficient measurement of oil and gas...

77 FR 18916 - Production Measurement Documents Incorporated by Reference

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-29

... products, or lubricating oils. Natural gas liquids and liquid petroleum gases are excluded from this... into the regulations governing oil, gas, and sulphur operations in the Outer Continental Shelf... measuring oil and gas production volumes. This rule will result in more accurate and efficient measurement...

SU-E-J-123: Assessing Segmentation Accuracy of Internal Volumes and Sub-Volumes in 4D PET/CT of Lung Tumors Using a Novel 3D Printed Phantom

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

Soultan, D; Murphy, J; James, C

2015-06-15

Purpose: To assess the accuracy of internal target volume (ITV) segmentation of lung tumors for treatment planning of simultaneous integrated boost (SIB) radiotherapy as seen in 4D PET/CT images, using a novel 3D-printed phantom. Methods: The insert mimics high PET tracer uptake in the core and 50% uptake in the periphery, by using a porous design at the periphery. A lung phantom with the insert was placed on a programmable moving platform. Seven breathing waveforms of ideal and patient-specific respiratory motion patterns were fed to the platform, and 4D PET/CT scans were acquired of each of them. CT images weremore » binned into 10 phases, and PET images were binned into 5 phases following the clinical protocol. Two scenarios were investigated for segmentation: a gate 30–70 window, and no gating. The radiation oncologist contoured the outer ITV of the porous insert with on CT images, while the internal void volume with 100% uptake was contoured on PET images for being indistinguishable from the outer volume in CT images. Segmented ITVs were compared to the expected volumes based on known target size and motion. Results: 3 ideal breathing patterns, 2 regular-breathing patient waveforms, and 2 irregular-breathing patient waveforms were used for this study. 18F-FDG was used as the PET tracer. The segmented ITVs from CT closely matched the expected motion for both no gating and gate 30–70 window, with disagreement of contoured ITV with respect to the expected volume not exceeding 13%. PET contours were seen to overestimate volumes in all the cases, up to more than 40%. Conclusion: 4DPET images of a novel 3D printed phantom designed to mimic different uptake values were obtained. 4DPET contours overestimated ITV volumes in all cases, while 4DCT contours matched expected ITV volume values. Investigation of the cause and effects of the discrepancies is undergoing.« less

CT volumetry of the skeletal tissues

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

Brindle, James M.; Alexandre Trindade, A.; Pichardo, Jose C.

2006-10-15

Computed tomography (CT) is an important and widely used modality in the diagnosis and treatment of various cancers. In the field of molecular radiotherapy, the use of spongiosa volume (combined tissues of the bone marrow and bone trabeculae) has been suggested as a means to improve the patient-specificity of bone marrow dose estimates. The noninvasive estimation of an organ volume comes with some degree of error or variation from the true organ volume. The present study explores the ability to obtain estimates of spongiosa volume or its surrogate via manual image segmentation. The variation among different segmentation raters was exploredmore » and found not to be statistically significant (p value >0.05). Accuracy was assessed by having several raters manually segment a polyvinyl chloride (PVC) pipe with known volumes. Segmentation of the outer region of the PVC pipe resulted in mean percent errors as great as 15% while segmentation of the pipe's inner region resulted in mean percent errors within {approx}5%. Differences between volumes estimated with the high-resolution CT data set (typical of ex vivo skeletal scans) and the low-resolution CT data set (typical of in vivo skeletal scans) were also explored using both patient CT images and a PVC pipe phantom. While a statistically significant difference (p value <0.002) between the high-resolution and low-resolution data sets was observed with excised femoral heads obtained following total hip arthroplasty, the mean difference between high-resolution and low-resolution data sets was found to be only 1.24 and 2.18 cm{sup 3} for spongiosa and cortical bone, respectively. With respect to differences observed with the PVC pipe, the variation between the high-resolution and low-resolution mean percent errors was a high as {approx}20% for the outer region volume estimates and only as high as {approx}6% for the inner region volume estimates. The findings from this study suggest that manual segmentation is a reasonably accurate and reliable means for the in vivo estimation of spongiosa volume. This work also provides a foundation for future studies where spongiosa volumes are estimated by various raters in more comprehensive CT data sets.« less

GEIGER-MULLER TYPE COUNTER TUBE

DOEpatents

Fowler, I.L.; Watt, L.A.K.

1959-12-15

A single counter tube capable of responding to a wide range of intensities is described. The counter tube comprises a tubular cathode and an anode extending centrally of the cathode. The spacing between the outer surface of the anode and the inner surface of the cathode is varied along the length of the tube to provide different counting volumes in adjacent portions of the tube. A large counting volume in one portion adjacent to a low-energy absorption window gives adequate sensitivity for measuring lowintensity radiation, while a smaller volume with close electrode spacing is provided in the counter to make possible measurement of intense garnma radiation fields.

Fuel cell with electrolyte feed system

DOEpatents

Feigenbaum, Haim

1984-01-01

A fuel cell having a pair of electrodes at the sites of electrochemical reactions of hydrogen and oxygen and a phosphoric acid electrolyte provided with an electrolyte supporting structure in the form of a laminated matrix assembly disposed between the electrodes. The matrix assembly is formed of a central layer disposed between two outer layers, each being permeable to the flow of the electrolyte. The central layer is provided with relatively large pores while the outer layers are provided with relatively small pores. An external reservoir supplies electrolyte via a feed means to the central layer to compensate for changes in electrolyte volume in the matrix assembly during the operation of fuel cell.

Method of making a sodium sulfur battery

DOEpatents

Elkins, Perry E.

1981-01-01

A method of making a portion of a sodium sulfur battery is disclosed. The battery portion made is a portion of the container which defines the volume for the cathodic reactant materials which are sulfur and sodium polysulfide materials. The container portion is defined by an outer metal casing with a graphite liner contained therein, the graphite liner having a coating on its internal diameter for sealing off the porosity thereof. The steel outer container and graphite pipe are united by a method which insures that at the operating temperature of the battery, relatively low electrical resistance exists between the two materials because they are in intimate contact with one another.

Differential distribution of proteins and lipids in detergent-resistant and detergent-soluble domains in rod outer segment plasma membranes and disks.

PubMed

Elliott, Michael H; Nash, Zack A; Takemori, Nobuaki; Fliesler, Steven J; McClellan, Mark E; Naash, Muna I

2008-01-01

Membrane heterogeneity plays a significant role in regulating signal transduction and other cellular activities. We examined the protein and lipid components associated with the detergent-resistant membrane (DRM) fractions from retinal rod outer segment (ROS) disk and plasma membrane-enriched preparations. Proteomics and correlative western blot analysis revealed the presence of alpha and beta subunits of the rod cGMP-gated ion channel and glucose transporter type 1, among other proteins. The glucose transporter was present exclusively in ROS plasma membrane (not disks) and was highly enriched in DRMs, as was the cGMP-gated channel beta-subunit. In contrast, the majority of rod opsin and ATP-binding cassette transporter A4 was localized to detergent-soluble domains in disks. As expected, the cholesterol : fatty acid mole ratio was higher in DRMs than in the corresponding parent membranes (disk and plasma membranes, respectively) and was also higher in disks compared to plasma membranes. Furthermore, the ratio of saturated : polyunsaturated fatty acids was also higher in DRMs compared to their respective parent membranes (disk and plasma membranes). These results confirm that DRMs prepared from both disks and plasma membranes are enriched in cholesterol and in saturated fatty acids compared to their parent membranes. The dominant fatty acids in DRMs were 16 : 0 and 18 : 0; 22 : 6n3 and 18 : 1 levels were threefold higher and twofold lower, respectively, in disk-derived DRMs compared to plasma membrane-derived DRMs. We estimate, based on fatty acid recovery that DRMs account for only approximately 8% of disks and approximately 12% of ROS plasma membrane.

Simulations of particle and heat fluxes in an ELMy H-mode discharge on EAST using BOUT++ code

NASA Astrophysics Data System (ADS)

Wu, Y. B.; Xia, T. Y.; Zhong, F. C.; Zheng, Z.; Liu, J. B.; team3, EAST

2018-05-01

In order to study the distribution and evolution of the transient particle and heat fluxes during edge-localized mode (ELM) bursts on the Experimental Advanced Superconducting Tokamak (EAST), the BOUT++ six-field two-fluid model is used to simulate the pedestal collapse. The profiles from the EAST H-mode discharge #56129 are used as the initial conditions. Linear analysis shows that the resistive ballooning mode and drift-Alfven wave are two dominant instabilities for the equilibrium, and play important roles in driving ELMs. The evolution of the density profile and the growing process of the heat flux at divertor targets during the burst of ELMs are reproduced. The time evolution of the poloidal structures of T e is well simulated, and the dominant mode in each stage of the ELM crash process is found. The studies show that during the nonlinear phase, the dominant mode is 5, and it changes to 0 when the nonlinear phase goes to saturation after the ELM crash. The time evolution of the radial electron heat flux, ion heat flux, and particle density flux at the outer midplane (OMP) are obtained, and the corresponding transport coefficients D r, χ ir, and χ er reach maximum around 0.3 ∼ 0.5 m2 s‑1 at ΨN = 0.9. The heat fluxes at outer target plates are several times larger than that at inner target plates, which is consistent with the experimental observations. The simulated profiles of ion saturation current density (j s) at the lower outboard (LO) divertor target are compared to those of experiments by Langmuir probes. The profiles near the strike point are similar, and the peak values of j s from simulation are very close to the measurements.

Viscosity of the saturated liquid phase of three fluorinated ethanes: R152a, R143a, and R125

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

Ripple, D.; Defibaugh, D.

1997-03-01

Data are reported for the viscosity of three saturated liquids over a temperature range from 255 K to 323 K. The liquids studied are the fluorinated compounds 1,1-difluoroethane (R152a), 1,1,1-trifluoroethane (R143a), and pentafluoroethane (R125). A capillary viscometer constructed of stainless steel and sapphire was used to obtain the data. The viscosity measurements have an expanded uncertainty of 2.4%. A free volume model of viscosity was used to correlate the data.

Three-dimensional arbitrary voxel shapes in spectroscopy with submillisecond TEs.

PubMed

Snyder, Jeff; Haas, Martin; Dragonu, Iulius; Hennig, Jürgen; Zaitsev, Maxim

2012-08-01

A novel spectroscopic method for submillisecond TEs and three-dimensional arbitrarily shaped voxels was developed and applied to phantom and in vivo measurements, with additional parallel excitation (PEX) implementation. A segmented spherical shell excitation trajectory was used in combination with appropriate radiofrequency weights for target selection in three dimensions. Measurements in a two-compartment phantom realized a TE of 955 µs, excellent spectral quality and comparable signal-to-noise ratios between accelerated (R = 2) and nonaccelerated modes. The two-compartment model allowed a comparison of the spectral suppression qualities of the method and, although outer volume signals were suppressed by factors of 1434 and 2246 compared with the theoretical unsuppressed case for the clinical and PEX modes, respectively, incomplete suppression of the outer volume (935 cm(3) compared with a target volume of 5.86 cm(3) ) resulted in a spectral contamination of 10.2% and 6.5% compared with the total signal. The method was also demonstrated in vivo in human brain on a clinical system at TE = 935 µs with good signal-to-noise ratio and spatial and spectral selection, and included LCModel relative quantification analysis. Eight metabolites showed significant fitting accuracy, including aspartate, N-acetylaspartylglutamate, glutathione and glutamate. Copyright © 2012 John Wiley & Sons, Ltd.

Effects of water saturation on P-wave propagation in fractured coals: An experimental perspective

NASA Astrophysics Data System (ADS)

Liu, Jie; Liu, Dameng; Cai, Yidong; Gan, Quan; Yao, Yanbin

2017-09-01

Internal structure of coalbed methane (CBM) reservoirs can be evaluated through ultrasonic measurements. The compressional wave that propagates in a fractured coal reservoir may indicate the internal coal structure and fluid characteristics. The P-wave propagation was proposed to study the relations between petrophysical parameters (including water saturation, fractures, porosity and permeability) of coals and the P-wave velocity (Vp), using a KON-NM-4A ultrasonic velocity meter. In this study, the relations between Vps and water saturations were established: Type I is mainly controlled by capillary of developed seepage pores. The controlling factors on Type II and Type III are internal homogeneity of pores/fractures and developed micro-fractures, respectively. Micro-fractures density linearly correlates with the Vp due to the fracture volume and dispersion of P-wave; and micro-fractures of types C and D have a priority in Vp. For dry coals, no clear relation exists between porosity, permeability and the Vp. However, as for water-saturated coals, the correlation coefficients of porosity, permeability and Vp are slightly improved. The Vp of saturated coals could be predicted with the equation of Vp-saturated = 1.4952Vp-dry-26.742 m/s. The relation between petrophysical parameters of coals and Vp under various water saturations can be used to evaluate the internal structure in fractured coals. Therefore, these relations have significant implications for coalbed methane (CBM) exploration.

Effects of molecular size and structure on self-diffusion coefficient and viscosity for saturated hydrocarbons having six carbon atoms.

PubMed

Iwahashi, Makio; Kasahara, Yasutoshi

2007-01-01

Self-diffusion coefficients and viscosities for the saturated hydrocarbons having six carbon atoms such as hexane, 2-methylpentane (2MP), 3-methylpentane (3MP), 2,2-dimethylbutane (22DMB), 2,3-dimethylbutane (23DMB), methylcyclopentane (McP) and cyclohexane (cH) were measured at various constant temperatures; obtained results were discussed in connection with their molar volumes, molecular structures and thermodynamic properties. The values of self-diffusion coefficients as the microscopic property were inversely proportional to those of viscosities as the macroscopic property. The order of their viscosities was almost same to those of their melting temperatures and enthalpies of fusion, which reflect the attractive interactions among their molecules. On the other hand, the order of the self-diffusion coefficients inversely related to the order of the melting temperatures and the enthalpies of the fusion. Namely, the compound having the larger attractive interaction mostly shows the less mobility in its liquid state, e.g., cyclohexane (cH), having the largest attractive interaction and the smallest molar volume exhibits an extremely large viscosity and small self-diffusion coefficient comparing with other hydrocarbons. However, a significant exception was 22DMB, being most close to a sphere: In spite of the smallest attractive interaction and the largest molar volume of 22DMB in the all samples, it has the thirdly larger viscosity and the thirdly smaller self-diffusion coefficient. Consequently, the dynamical properties such as self-diffusion and viscosity for the saturated hydrocarbons are determined not only by their attractive interactions but also by their molecular structures.

49 CFR 178.601 - General requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... proportion to the reduction in volume. (4) Variation 4. Variations are permitted in outer packagings of a... steel; (viii) An increase greater than 10% or any decrease in the steel thickness of the head, body, or... body), type (e.g., mechanically seamed or welded flange), and materials of closure (other than the...

49 CFR 178.601 - General requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... proportion to the reduction in volume. (4) Variation 4. Variations are permitted in outer packagings of a... steel; (viii) An increase greater than 10% or any decrease in the steel thickness of the head, body, or... body), type (e.g., mechanically seamed or welded flange), and materials of closure (other than the...

49 CFR 178.601 - General requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... proportion to the reduction in volume. (4) Variation 4. Variations are permitted in outer packagings of a... steel; (viii) An increase greater than 10% or any decrease in the steel thickness of the head, body, or... body), type (e.g., mechanically seamed or welded flange), and materials of closure (other than the...

30 CFR 250.444 - What are the choke manifold requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.444 What are the choke... corrosiveness, volume, and abrasiveness of drilling fluids and well fluids that you may encounter. (b) Choke...

Photoelectronic Sensor with Gold Nanoparticle Plasmon Antenna

DTIC Science & Technology

2016-07-20

on glass substrate, GNP is absorbed on the film. After removing outer protein by UV ozone, TiO2 is deposited again and annealed. As optical... SiO2 Thin Films by CO2 Laser Annealing for Polycrystalline Silicon Thin Film Transistors”, AMD8-3L, The International Display Workshops Volume 21

Impacts of signal system timings on rain related congestion.

DOT National Transportation Integrated Search

2010-06-01

It is known that inclement weather can affect traffic volumes, vehicle speeds, speed variance, saturation flow rates, and sometimes : discharge rates from traffic signals. These parameters in turn can have a significant impact on the efficiency of tr...

nZVI injection into variably saturated soils: Field and modeling study

NASA Astrophysics Data System (ADS)

Chowdhury, Ahmed I. A.; Krol, Magdalena M.; Kocur, Christopher M.; Boparai, Hardiljeet K.; Weber, Kela P.; Sleep, Brent E.; O'Carroll, Denis M.

2015-12-01

Nano-scale zero valent iron (nZVI) has been used at a number of contaminated sites over the last decade. At most of these sites, significant decreases in contaminant concentrations have resulted from the application of nZVI. However, limited work has been completed investigating nZVI field-scale mobility. In this study, a field test was combined with numerical modeling to examine nZVI reactivity along with transport properties in variably saturated soils. The field test consisted of 142 L of carboxymethyle cellulose (CMC) stabilized monometallic nZVI synthesized onsite and injected into a variably saturated zone. Periodic groundwater samples were collected from the injection well, as well as, from two monitoring wells to analyze for chlorinated solvents and other geochemistry indicators. This study showed that CMC stabilized monometallic nZVI was able to decrease tricholorethene (TCE) concentrations in groundwater by more than 99% from the historical TCE concentrations. A three dimensional, three phase, finite difference numerical simulator, (CompSim) was used to further investigate nZVI and polymer transport at the variably saturated site. The model was able to accurately predict the field observed head data without parameter fitting. In addition, the numerical simulator estimated the mass of nZVI delivered to the saturated and unsaturated zones and distinguished the nZVI phase (i.e. aqueous or attached). The simulation results showed that the injected slurry migrated radially outward from the injection well, and therefore nZVI transport was governed by injection velocity and viscosity of the injected solution. A suite of sensitivity analyses was performed to investigate the impact of different injection scenarios (e.g. different volume and injection rate) on nZVI migration. Simulation results showed that injection of a higher nZVI volume delivered more iron particles at a given distance; however, the travel distance was not proportional to the increase in volume. Moreover, simulation results showed that using a 1D transport equation to simulate nZVI migration in the subsurface may overestimate the travel distance. This is because the 1D transport equation assumes a constant velocity while pore water velocity radially decreases from the well during injection. This study suggests that on-site synthesized nZVI particles are mobile in the subsurface and that a numerical simulator can be a valuable tool for optimal design of nZVI field applications.

The MASSIVE survey - VIII. Stellar velocity dispersion profiles and environmental dependence of early-type galaxies

NASA Astrophysics Data System (ADS)

Veale, Melanie; Ma, Chung-Pei; Greene, Jenny E.; Thomas, Jens; Blakeslee, John P.; Walsh, Jonelle L.; Ito, Jennifer

2018-02-01

We measure the radial profiles of the stellar velocity dispersions, σ(R), for 90 early-type galaxies (ETGs) in the MASSIVE survey, a volume-limited integral-field spectroscopic (IFS) galaxy survey targeting all northern-sky ETGs with absolute K-band magnitude MK < -25.3 mag, or stellar mass M* ≳ 4 × 1011M⊙, within 108 Mpc. Our wide-field 107 arcsec × 107 arcsec IFS data cover radii as large as 40 kpc, for which we quantify separately the inner (2 kpc) and outer (20 kpc) logarithmic slopes γinner and γouter of σ(R). While γinner is mostly negative, of the 56 galaxies with sufficient radial coverage to determine γouter we find 36 per cent to have rising outer dispersion profiles, 30 per cent to be flat within the uncertainties and 34 per cent to be falling. The fraction of galaxies with rising outer profiles increases with M* and in denser galaxy environment, with 10 of the 11 most massive galaxies in our sample having flat or rising dispersion profiles. The strongest environmental correlations are with local density and halo mass, but a weaker correlation with large-scale density also exists. The average γouter is similar for brightest group galaxies, satellites and isolated galaxies in our sample. We find a clear positive correlation between the gradients of the outer dispersion profile and the gradients of the velocity kurtosis h4. Altogether, our kinematic results suggest that the increasing fraction of rising dispersion profiles in the most massive ETGs are caused (at least in part) by variations in the total mass profiles rather than in the velocity anisotropy alone.

Biofilter design for effective nitrogen removal from stormwater - influence of plant species, inflow hydrology and use of a saturated zone.

PubMed

Payne, Emily G I; Pham, Tracey; Cook, Perran L M; Fletcher, Tim D; Hatt, Belinda E; Deletic, Ana

2014-01-01

The use of biofilters to remove nitrogen and other pollutants from urban stormwater runoff has demonstrated varied success across laboratory and field studies. Design variables including plant species and use of a saturated zone have large impacts upon performance. A laboratory column study of 22 plant species and designs with varied outlet configuration was conducted across a 1.5-year period to further investigate the mechanisms and influences driving biofilter nitrogen processing. This paper presents outflow concentrations of total nitrogen from two sampling events across both 'wet' and 'dry' frequency dosing, and from sampling across two points in the outflow hydrograph. All plant species were effective under conditions of frequent dosing, but extended drying increased variation between species and highlighted the importance of a saturated zone in maintaining biofilter function. The saturated zone also effectively treated the volume of stormwater stored between inflow events, but this extended detention provided no additional benefit alongside the rapid processing of the highest performing species. Hence, the saturated zone reduced performance differences between plant species, and potentially acts as an 'insurance policy' against poor sub-optimal plant selection. The study shows the importance of biodiversity and inclusion of a saturated zone in protecting against climate variability.

Influence of Water Saturation on Thermal Conductivity in Sandstones

NASA Astrophysics Data System (ADS)

Fehr, A.; Jorand, R.; Koch, A.; Clauser, C.

2009-04-01

Information on thermal conductivity of rocks and soils is essential in applied geothermal and hydrocarbon maturation research. In this study, we investigate the dependence of thermal conductivity on the degree of water saturation. Measurements were made on five sandstones from different outcrops in Germany. In a first step, we characterized the samples with respect to mineralogical composition, porosity, and microstructure by nuclear magnetic resonance (NMR) and mercury injection. We measured thermal conductivity with an optical scanner at different levels of water saturation. Finally we present a simple and easy model for the correlation of thermal conductivity and water saturation. Thermal conductivity decreases in the course of the drying of the rock. This behaviour is not linear and depends on the microstructure of the studied rock. We studied different mixing models for three phases: mineral skeleton, water and air. For argillaceous sandstones a modified arithmetic model works best which considers the irreducible water volume and different pore sizes. For pure quartz sandstones without clay minerals, we use the same model for low water saturations, but for high water saturations a modified geometric model. A clayey sandstone rich in feldspath shows a different behaviour which cannot be explained by simple models. A better understanding will require measurements on additional samples which will help to improve the derived correlations and substantiate our findings.

Dependence of Thermal Conductivity on Water Saturation of Sandstones

NASA Astrophysics Data System (ADS)

Fehr, A.; Jorand, R.; Koch, A.; Clauser, C.

2008-12-01

Information on thermal conductivity of rocks and soils is essential in applied geothermal and hydrocarbon maturation research. In this study, we investigate the dependence of thermal conductivity on the degree of water saturation. Measurements were made on five sandstones from different outcrops in Germany. In a first step, we characterized the samples with respect to mineralogical composition, porosity, and microstructure by nuclear magnetic resonance (NMR) and mercury injection. We measured thermal conductivity with an optical scanner at different levels of water saturation. Finally we present a simple and easy model for the correlation of thermal conductivity and water saturation. Thermal conductivity decreases in the course of the drying of the rock. This behaviour is not linear and depends on the microstructure of the studied rock. We studied different mixing models for three phases: mineral skeleton, water and air. For argillaceous sandstones a modified arithmetic model works best which considers the irreducible water volume and different pore sizes. For pure quartz sandstones without clay minerals, we use the same model for low water saturations, but for high water saturations a modified geometric model. A clayey sandstone rich in feldspath shows a different behaviour which cannot be explained by simple models. A better understanding will require measurements on additional samples which will help to improve the derived correlations and substantiate our findings.

The phototransduction machinery in the rod outer segment has a strong efficacy gradient

PubMed Central

Mazzolini, Monica; Facchetti, Giuseppe; Andolfi, Laura; Proietti Zaccaria, Remo; Tuccio, Salvatore; Treu, Johannes; Altafini, Claudio; Di Fabrizio, Enzo M.; Lazzarino, Marco; Rapp, Gert; Torre, Vincent

2015-01-01

Rod photoreceptors consist of an outer segment (OS) and an inner segment. Inside the OS a biochemical machinery transforms the rhodopsin photoisomerization into electrical signal. This machinery has been treated as and is thought to be homogenous with marginal inhomogeneities. To verify this assumption, we developed a methodology based on special tapered optical fibers (TOFs) to deliver highly localized light stimulations. By using these TOFs, specific regions of the rod OS could be stimulated with spots of light highly confined in space. As the TOF is moved from the OS base toward its tip, the amplitude of saturating and single photon responses decreases, demonstrating that the efficacy of the transduction machinery is not uniform and is 5–10 times higher at the base than at the tip. This gradient of efficacy of the transduction machinery is attributed to a progressive depletion of the phosphodiesterase along the rod OS. Moreover we demonstrate that, using restricted spots of light, the duration of the photoresponse along the OS does not increase linearly with the light intensity as with diffuse light. PMID:25941368

Process for separating dissolved solids from a liquid using an anti-solvent and multiple effect evaporators

DOEpatents

Daniels, Edward J.; Jody, Bassam J.; Bonsignore, Patrick V.

1994-01-01

A process and system for treating aluminum salt cake containing water soluble halide salts by contacting the salt cake with water to dissolve water soluble halide salts forming a saturated brine solution. Transporting a portion of about 25% of the saturated brine solution to a reactor and introducing into the saturated brine solution at least an equal volume of a water-miscible low-boiling organic material such as acetone to precipitate a portion of the dissolved halide salts forming a three-phase mixture of an aqueous-organic-salt solution phase and a precipitated salt phase and an organic rich phase. The precipitated salt phase is separated from the other phases and the organic rich phase is recycled to the reactor. The remainder of the saturated brine solution is sent to a multiple effect evaporator having a plurality of stages with the last stage thereof producing low grade steam which is used to boil off the organic portion of the solution which is recycled.

Process for separating dissolved solids from a liquid using an anti-solvent and multiple effect evaporators

DOEpatents

Daniels, E.J.; Jody, B.J.; Bonsignore, P.V.

1994-07-19

A process and system are disclosed for treating aluminum salt cake containing water soluble halide salts by contacting the salt cake with water to dissolve water soluble halide salts forming a saturated brine solution. Transporting a portion of about 25% of the saturated brine solution to a reactor and introducing into the saturated brine solution at least an equal volume of a water-miscible low-boiling organic material such as acetone to precipitate a portion of the dissolved halide salts forming a three-phase mixture of an aqueous-organic-salt solution phase and a precipitated salt phase and an organic rich phase. The precipitated salt phase is separated from the other phases and the organic rich phase is recycled to the reactor. The remainder of the saturated brine solution is sent to a multiple effect evaporator having a plurality of stages with the last stage thereof producing low grade steam which is used to boil off the organic portion of the solution which is recycled. 3 figs.

Respiratory potential in sapwood of old versus young ponderosa pine trees in the Pacific Northwest.

PubMed

Pruyn, Michele L; Gartner, Barbara L; Harmon, Mark E

2002-02-01

Our primary objective was to present and test a new technique for in vitro estimation of respiration of cores taken from old trees to determine respiratory trends in sapwood. Our secondary objective was to quantify effects of tree age and stem position on respiratory potential (rate of CO2 production of woody tissue under standardized laboratory conditions). We extracted cores from one to four vertical positions in boles of +200-, +50- and +15-year-old Pinus ponderosa Dougl. ex Laws. trees. Cores were divided into five segments corresponding to radial depths of inner bark; outer, middle and inner sapwood; and heartwood. Data suggested that core segment CO2 production was an indicator of its respiratory activity, and that potential artifacts caused by wounding and extraction were minimal. On a dry mass basis, respiratory potential of inner bark was 3-15 times greater than that of sapwood at all heights for all ages (P < 0.0001). Within sapwood at all heights and in all ages of trees, outer sapwood had a 30-60% higher respiratory potential than middle or inner sapwood (P < 0.005). Heartwood had only 2-10% of the respiratory potential of outer sapwood. For all ages of trees, sapwood rings produced in the same calendar year released over 50% more CO2 at treetops than at bases (P < 0.0001). When scaled to the whole-tree level on a sapwood volume basis, sapwood of younger trees had higher respiratory potential than sapwood of older trees. In contrast, the trend was reversed when using the outer-bark surface area of stems as a basis for comparing respiratory potential. The differences observed in respiratory potential calculated on a core dry mass, sapwood volume, or outer-bark surface area basis clearly demonstrate that the resulting trends within and among trees are determined by the way in which the data are expressed. Although these data are based on core segments rather than in vivo measurements, we conclude that the relative differences are probably valid even if the absolute differences are not.

Study of hydraulic properties of binary beads mixture as porous media in sustainable urban drainage system

NASA Astrophysics Data System (ADS)

Abdullah, Muhammad Faiz; Puay, How Tion; Zakaria, Nor Azazi

2017-10-01

Sustainable Urban Drainage System (SuDS) such as swales and rain gardens is showing growing popularity as a green technology for stormwater management and it can be used in all types of development to provide a natural approach to managing drainage. Soil permeability is a critical factor in selecting the right SuDS technique for a site. On this basis, we have set up a laboratory experiment to investigate the porosity and saturated hydraulic conductivity of single size and binary (two sizes) mixture using column-test as a preliminary investigation with two sets of glass beads with different sizes are used in this study. The porosity and saturated hydraulic conductivity for varies volume fraction of the course and fine glass beads were measured. It was found that the porosity of the binary mixture does not increase with the increment of the ratio of coarse to fine beads until the volume fraction of fine particles is equal to the coarse component. Saturated hydraulic conductivity result shows that the assumption of random packing was not achieved at the higher coarse ratio where most of the fine particles tend to sit at the bottom of the column forming separate layers which lower the overall hydraulic conductivity value.

Well log analysis to assist the interpretation of 3-D seismic data at Milne Point, north slope of Alaska

USGS Publications Warehouse

Lee, Myung W.

2005-01-01

In order to assess the resource potential of gas hydrate deposits in the North Slope of Alaska, 3-D seismic and well data at Milne Point were obtained from BP Exploration (Alaska), Inc. The well-log analysis has three primary purposes: (1) Estimate gas hydrate or gas saturations from the well logs; (2) predict P-wave velocity where there is no measured P-wave velocity in order to generate synthetic seismograms; and (3) edit P-wave velocities where degraded borehole conditions, such as washouts, affected the P-wave measurement significantly. Edited/predicted P-wave velocities were needed to map the gas-hydrate-bearing horizons in the complexly faulted upper part of 3-D seismic volume. The estimated gas-hydrate/gas saturations from the well logs were used to relate to seismic attributes in order to map regional distribution of gas hydrate inside the 3-D seismic grid. The P-wave velocities were predicted using the modified Biot-Gassmann theory, herein referred to as BGTL, with gas-hydrate saturations estimated from the resistivity logs, porosity, and clay volume content. The effect of gas on velocities was modeled using the classical Biot-Gassman theory (BGT) with parameters estimated from BGTL.

An Assessment of Helium Evolution from Helium-Saturated Propellant Depressurization in Space

NASA Technical Reports Server (NTRS)

Nguyen, Bich N.; Best, Frederick; Wong, Tony; Kurwitz, Cable; McConnaughey, H. (Technical Monitor)

2001-01-01

Helium evolution from the transfer of helium-saturated propellant in space is quantified to assess its impacts from creating two-phase gas/liquid flow from the supply tank, gas injection into the receiving tank, and liquid discharge from the receiving tank. Propellant transfer takes place between two similar tanks whose maximum storage capacity is approximately 2.55 cubic meters each. The maximum on-orbit propellants transfer capability is 9000 lbm (fuel and oxidizer). The transfer line is approximately 1.27 cm in diameter and 6096 cm in length and comprised of the fluid interconnect system (FICS), the orbiter propellant transfer system (OPTS), and the International Space Station (ISS) propulsion module (ISSPM). The propellant transfer rate begins at approximately 11 liter per minute (lpm) and subsequently drops to approximately 0.5 lpm. The tank nominal operating pressure is approximately 1827 kPa (absolute). The line pressure drops for Monomethy1hydrazine (MMH) and Nitrogen tetroxide (NTO) at 11.3 lpm are approximately 202 kPa and 302 kPa, respectively. The pressure-drop results are based on a single-phase flow. The receiving tank is required to vent from approximately 1827 kPa to a lower pressure to affect propellant transfer. These pressure-drop scenarios cause the helium-saturated propellants to release excess helium. For tank ullage venting, the maximum volumes of helium evolved at tank pressure are approximately 0.5 ft3 for MMH and 2 ft3 for NTO. In microgravity environment, due to lack of body force, the helium evolution from a liquid body acts to propel it, which influences its fluid dynamics. For propellant transfer, the volume fractions of helium evolved at line pressure are 0.1% by volume for MMH and 0.6 % by volume for NTO at 11.3 lpm. The void fraction of helium evolved varies as an approximate second order power function of flow rate.

The formation and effect of outer-ply microcracks in cross-ply laminates - A variational approach

NASA Technical Reports Server (NTRS)

Nairn, John A.; Hu, Shoufeng

1992-01-01

The paper presents a variational mechanics analysis of the stresses and energy release rate in a (90m/0n)s laminate, with account taken of the observed existence of staggered microcracks. It is found that the load required to initiate microcracks is significantly lower for (90m/0n)s laminates than for (0n/90m)s laminates. It is also found that (90m/0n)s laminates are characterized by a lower saturation crack density and that no bending effects tend to promote mode I delamination in (90m/0n)s laminates.

Phospholipid component volumes: determination and application to bilayer structure calculations.

PubMed

Armen, R S; Uitto, O D; Feller, S E

1998-08-01

We present a new method for the determination of bilayer structure based on a combination of computational studies and laboratory experiments. From molecular dynamics simulations, the volumes of submolecular fragments of saturated and unsaturated phosphatidylcholines in the liquid crystalline state have been extracted with a precision not available experimentally. Constancy of component volumes, both among different lipids and as a function of membrane position for a given lipid, have been examined. The component volumes were then incorporated into the liquid crystallographic method described by Wiener and White (1992. Biophys. J. 61:434-447, and references therein) for determining the structure of a fluid-phase dioleoylphosphatidylcholine bilayer from x-ray and neutron diffraction experiments.

Phospholipid component volumes: determination and application to bilayer structure calculations.

PubMed Central

Armen, R S; Uitto, O D; Feller, S E

1998-01-01

We present a new method for the determination of bilayer structure based on a combination of computational studies and laboratory experiments. From molecular dynamics simulations, the volumes of submolecular fragments of saturated and unsaturated phosphatidylcholines in the liquid crystalline state have been extracted with a precision not available experimentally. Constancy of component volumes, both among different lipids and as a function of membrane position for a given lipid, have been examined. The component volumes were then incorporated into the liquid crystallographic method described by Wiener and White (1992. Biophys. J. 61:434-447, and references therein) for determining the structure of a fluid-phase dioleoylphosphatidylcholine bilayer from x-ray and neutron diffraction experiments. PMID:9675175

Double emulsion formation through hierarchical flow-focusing microchannel

NASA Astrophysics Data System (ADS)

Azarmanesh, Milad; Farhadi, Mousa; Azizian, Pooya

2016-03-01

A microfluidic device is presented for creating double emulsions, controlling their sizes and also manipulating encapsulation processes. As a result of three immiscible liquids' interaction using dripping instability, double emulsions can be produced elegantly. Effects of dimensionless numbers are investigated which are Weber number of the inner phase (Wein), Capillary number of the inner droplet (Cain), and Capillary number of the outer droplet (Caout). They affect the formation process, inner and outer droplet size, and separation frequency. Direct numerical simulation of governing equations was done using volume of fluid method and adaptive mesh refinement technique. Two kinds of double emulsion formation, the two-step and the one-step, were simulated in which the thickness of the sheath of double emulsions can be adjusted. Altering each dimensionless number will change detachment location, outer droplet size and droplet formation period. Moreover, the decussate regime of the double-emulsion/empty-droplet is observed in low Wein. This phenomenon can be obtained by adjusting the Wein in which the maximum size of the sheath is discovered. Also, the results show that Cain has significant influence on the outer droplet size in the two-step process, while Caout affects the sheath in the one-step formation considerably.

A hypersonic aeroheating calculation method based on inviscid outer edge of boundary layer parameters

NASA Astrophysics Data System (ADS)

Meng, ZhuXuan; Fan, Hu; Peng, Ke; Zhang, WeiHua; Yang, HuiXin

2016-12-01

This article presents a rapid and accurate aeroheating calculation method for hypersonic vehicles. The main innovation is combining accurate of numerical method with efficient of engineering method, which makes aeroheating simulation more precise and faster. Based on the Prandtl boundary layer theory, the entire flow field is divided into inviscid and viscid flow at the outer edge of the boundary layer. The parameters at the outer edge of the boundary layer are numerically calculated from assuming inviscid flow. The thermodynamic parameters of constant-volume specific heat, constant-pressure specific heat and the specific heat ratio are calculated, the streamlines on the vehicle surface are derived and the heat flux is then obtained. The results of the double cone show that at the 0° and 10° angle of attack, the method of aeroheating calculation based on inviscid outer edge of boundary layer parameters reproduces the experimental data better than the engineering method. Also the proposed simulation results of the flight vehicle reproduce the viscid numerical results well. Hence, this method provides a promising way to overcome the high cost of numerical calculation and improves the precision.

NIF Double Shell outer/inner shell collision experiments

NASA Astrophysics Data System (ADS)

Merritt, E. C.; Loomis, E. N.; Wilson, D. C.; Cardenas, T.; Montgomery, D. S.; Daughton, W. S.; Dodd, E. S.; Desjardins, T.; Renner, D. B.; Palaniyappan, S.; Batha, S. H.; Khan, S. F.; Smalyuk, V.; Ping, Y.; Amendt, P.; Schoff, M.; Hoppe, M.

2017-10-01

Double shell capsules are a potential low convergence path to substantial alpha-heating and ignition on NIF, since they are predicted to ignite and burn at relatively low temperatures via volume ignition. Current LANL NIF double shell designs consist of a low-Z ablator, low-density foam cushion, and high-Z inner shell with liquid DT fill. Central to the Double Shell concept is kinetic energy transfer from the outer to inner shell via collision. The collision determines maximum energy available for compression and implosion shape of the fuel. We present results of a NIF shape-transfer study: two experiments comparing shape and trajectory of the outer and inner shells at post-collision times. An outer-shell-only target shot measured the no-impact shell conditions, while an `imaging' double shell shot measured shell conditions with impact. The `imaging' target uses a low-Z inner shell and is designed to perform in similar collision physics space to a high-Z double shell but can be radiographed at 16keV, near the viable 2DConA BL energy limit. Work conducted under the auspices of the U.S. DOE by LANL under contract DE-AC52-06NA25396.

Stability of metal-rich very massive stars

NASA Astrophysics Data System (ADS)

Goodman, J.; White, Christopher J.

2016-02-01

We revisit the stability of very massive non-rotating main-sequence stars at solar metallicity, with the goal of understanding whether radial pulsations set a physical upper limit to stellar mass. Models of up to 938 solar masses are constructed with the MESA code, and their linear stability in the fundamental mode, assumed to be the most dangerous, is analysed with a fully non-adiabatic method. Models above 100 M⊙ have extended tenuous atmospheres (`shelves') that affect the stability of the fundamental. Even when positive, this growth rate is small, in agreement with previous results. We argue that small growth rates lead to saturation at small amplitudes that are not dangerous to the star. A mechanism for saturation is demonstrated involving non-linear parametric coupling to short-wavelength g-modes and the damping of the latter by radiative diffusion. The shelves are subject to much more rapidly growing strange modes. This also agrees with previous results but is extended here to higher masses. The strange modes probably saturate via shocks rather than mode coupling but have very small amplitudes in the core, where almost all of the stellar mass resides. Although our stellar models are hydrostatic, the structure of their outer parts suggests that optically thick winds, driven by some combination of radiation pressure, transonic convection, and strange modes, are more likely than pulsation in the fundamental mode to limit the main-sequence lifetime.

Effect of graphite content on magnetic and mechanical properties of TiC-TiN-Mo-Ni cermets

NASA Astrophysics Data System (ADS)

Zhang, Man; Yang, Qingqing; Xiong, Weihao; Huang, Bin; Ruan, Linji; Mao, Qiao; Li, Shengtao

2018-04-01

TiC-10TiN-6Mo-xGr-yNi (mol%, Gr represents graphite, x = 0, 2, 4, 6, 8, and y = 15, 30) cermets were prepared by powder metallurgy method, in order to inverstigate the effect of Gr content on magnetic and mechanical properties of TiC-TiN-Mo-Ni cermets. Room-temperature (RT) saturation magnetization (Ms) and remanence (Mr) of cermets increased with increasing x. This was mainly attributed to that the total content of non-ferromagnetic carbonitride-forming elements Ti and Mo in Ni-based binder phase decreased with increasing x. At the same x, cermets for y = 15 had lower RT Ms and Mr than those for y = 30. Cermets containing more than 2 mol% Gr became ferromagnetic at RT. Bending strength of cermets first increased and then decreased with increasing x. It reached the maximum at x = 2, mainly due to high total content of solutes Ti and Mo in Ni-based binder phase, and moderate thickness of outer rim of Ti(C,N) ceramic grains. Hardness of cermets was not significantly affected by x, mainly due to the combined action of the decrease of the total content of Ti and Mo in binder phase and the increase of the volume fraction of ceramic grains. At the same x, cermets for y = 15 had lower bending strength and higher hardness than those for y = 30.

Aquatic life at high altitude: respiratory adaptations in the Lake Titicaca frog, Telmatobius culeus.

PubMed

Hutchison, V H; Haines, H B; Engbretson, G

1976-07-01

Telmatobius culeus has a combination of behavioral, morphological and physiological adaptations which allows an aquatic life in cool (10 degrees C) O2-saturated (at 100 mm Hg) waters at high altitude (3812 m). The skin surgace area is increased by pronounced folds and the cutaneous capillaries penetrate to the outer layers of the skin. The erythrocyte volume (394 mu3) is the smallest reported for amphibians. The P50 (15.6 at ph 7.65 and 10 degrees C) is the lowest, and the erythrocyte count (729 - 103/mm3) the highest for an anuran. The O2 capacity (11.7 vol%), hemoglobin (8.1 g/100 ml), hemoglobin concentration (0.281 pg/mu3) and hematocrit (27.9%) measured at 18 degrees C and 3800 m are all elevated in comparison with most amphibians. The O2 dissociation curve is sigmoid (n = 2), the Bohr factor is small (deltalog P50/deltapH = -0.30) and the buffering capacity (-8.9 m M HCO3 - 1-1) is typical for an aquatic amphibian. The metabolic rate (14.1 mul -g-1-h-u) is the lowest reported for a frog and among amphibians only the giant salamanders (Amphiuma, Necturus and Siren) have lower values. If prevent from surfacing in hypoxic waters, the frogs ventilate the skin by "bobbing" behavior; if allowed to surface, they will ventilate the small lungs and the metabolic rate increases to 23 mul-g-1-h-1.

The influence of gravity on the formation of amyloplasts in columella cells of Zea mays L

NASA Technical Reports Server (NTRS)

Moore, R.; Fondren, W. M.; Koon, E. C.; Wang, C. L.

1986-01-01

Columella (i.e., putative graviperceptive) cells of Zea mays seedlings grown in the microgravity of outer space allocate significantly less volume to putative statoliths (amyloplasts) than do columella cells of Earth-grown seedlings. Amyloplasts of flight-grown seedlings are significantly smaller than those of ground controls, as is the average volume of individual starch grains. Similarly, the relative volume of starch in amyloplasts in columella cells of flight-grown seedlings is significantly less than that of Earth-grown seedlings. Microgravity does not significantly alter the volume of columella cells, the average number of amyloplasts per columella cell, or the number of starch grains per amyloplast. These results are discussed relative to the influence of gravity on cellular and organellar structure.

[Morphological analysis of bone dynamics and metabolic bone disease. Effect of loading on bone tissue].

PubMed

Sakai, Akinori

2011-04-01

We developed a voluntarily climbing animal model to investigate the effect of skeletal loading on bone tissue. At the cross section of the mid-femur, climbing exercise increases outer diameter and area of cortical bone. The mechanical strength of the femur is increased. This change of cortical volume and structure is more marked in anti-gravity exercise, such as climbing and jumping, than aerobic exercise. At the bone marrow area, climbing exercise increases trabecular bone volume and osteoblast number, while it decreases fat volume and adipocyte number. Skeletal loading promotes differentiation from mesenchymal stem cells to osteoblasts and suppresses that to adipocytes by facilitating the signal through PTH÷PTHrP receptor.

Concentration and saturation effects of tethered polymer chains on adsorbing surfaces

NASA Astrophysics Data System (ADS)

Descas, Radu; Sommer, Jens-Uwe; Blumen, Alexander

2006-12-01

We consider end-grafted chains at an adsorbing surface under good solvent conditions using Monte Carlo simulations and scaling arguments. Grafting of chains allows us to fix the surface concentration and to study a wide range of surface concentrations from the undersaturated state of the surface up to the brushlike regime. The average extension of single chains in the direction parallel and perpendicular to the surface is analyzed using scaling arguments for the two-dimensional semidilute surface state according to Bouchaud and Daoud [J. Phys. (Paris) 48, 1991 (1987)]. We find good agreement with the scaling predictions for the scaling in the direction parallel to the surface and for surface concentrations much below the saturation concentration (dense packing of adsorption blobs). Increasing the grafting density we study the saturation effects and the oversaturation of the adsorption layer. In order to account for the effect of excluded volume on the adsorption free energy we introduce a new scaling variable related with the saturation concentration of the adsorption layer (saturation scaling). We show that the decrease of the single chain order parameter (the fraction of adsorbed monomers on the surface) with increasing concentration, being constant in the ideal semidilute surface state, is properly described by saturation scaling only. Furthermore, the simulation results for the chains' extension from higher surface concentrations up to the oversaturated state support the new scaling approach. The oversaturated state can be understood using a geometrical model which assumes a brushlike layer on top of a saturated adsorption layer. We provide evidence that adsorbed polymer layers are very sensitive to saturation effects, which start to influence the semidilute surface scaling even much below the saturation threshold.

Single well surfactant test to evaluate surfactant floods using multi tracer method

DOEpatents

Sheely, Clyde Q.

1979-01-01

Data useful for evaluating the effectiveness of or designing an enhanced recovery process said process involving mobilizing and moving hydrocarbons through a hydrocarbon bearing subterranean formation from an injection well to a production well by injecting a mobilizing fluid into the injection well, comprising (a) determining hydrocarbon saturation in a volume in the formation near a well bore penetrating formation, (b) injecting sufficient mobilizing fluid to mobilize and move hydrocarbons from a volume in the formation near the well bore, and (c) determining the hydrocarbon saturation in a volume including at least a part of the volume of (b) by an improved single well surfactant method comprising injecting 2 or more slugs of water containing the primary tracer separated by water slugs containing no primary tracer. Alternatively, the plurality of ester tracers can be injected in a single slug said tracers penetrating varying distances into the formation wherein the esters have different partition coefficients and essentially equal reaction times. The single well tracer method employed is disclosed in U.S. Pat. No. 3,623,842. This method designated the single well surfactant test (SWST) is useful for evaluating the effect of surfactant floods, polymer floods, carbon dioxide floods, micellar floods, caustic floods and the like in subterranean formations in much less time and at much reduced cost compared to conventional multiwell pilot tests.

Power conditioning equipment for a thermoelectric outer planet spacecraft, volume 1, book 2

NASA Technical Reports Server (NTRS)

Andrews, R. E. (Editor)

1972-01-01

The design and development of power conditioning equipment for the thermoelectric outer planet spacecraft program are considered. One major aspect of the program included the design, assembly and test of various breadboard power conditioning elements. Among others these included a quad-redundant shunt regulator, a high voltage traveling wave tube dc-to-dc converter, two-phase gyro inverters and numerous solid state switching circuits. Many of these elements were arranged in a typical subsystem configuration and tests were conducted which demonstrated basic element compatibility. In parallel with the development of the basic power conditioning elements, system studies were continued. The salient features of the selected power subsystem configuration are presented.

Method of making a sodium sulfur battery

DOEpatents

Elkins, P. E.

1981-09-22

A method of making a portion of a sodium sulfur battery is disclosed. The battery portion made is a portion of the container which defines the volume for the cathodic reactant materials which are sulfur and sodium polysulfide materials. The container portion is defined by an outer metal casing with a graphite liner contained therein, the graphite liner having a coating on its internal diameter for sealing off the porosity thereof. The steel outer container and graphite pipe are united by a method which insures that at the operating temperature of the battery, relatively low electrical resistance exists between the two materials because they are in intimate contact with one another. 3 figs.

Guidance and Navigation Requirements for Unmanned Flyby and Swingby Missions to the Outer Planets. Volume 3; Low Thrust Missions, Phase B

NASA Technical Reports Server (NTRS)

1970-01-01

The guidance and navigation requirements for unmanned missions to the outer planets, assuming constant, low thrust, ion propulsion are discussed. The navigational capability of the ground based Deep Space Network is compared to the improvements in navigational capability brought about by the addition of guidance and navigation related onboard sensors. Relevant onboard sensors include: (1) the optical onboard navigation sensor, (2) the attitude reference sensors, and (3) highly sensitive accelerometers. The totally ground based, and the combination ground based and onboard sensor systems are compared by means of the estimated errors in target planet ephemeris, and the spacecraft position with respect to the planet.

30 CFR 250.514 - Well-control fluids, equipment, and operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... equivalent well-control fluid volume shall be calculated and posted near the operator's station. A mechanical... 30 Mineral Resources 2 2010-07-01 2010-07-01 false Well-control fluids, equipment, and operations... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Completion...

Torsional Oscillations of the Earths's Core

NASA Technical Reports Server (NTRS)

Hide, Raymond; Boggs, Dale H.; Dickey, Jean O.

1997-01-01

Torsional oscillations of the Earth's liquid metallic outer core are investigated by diving the core into twenty imaginary e1qui-volume annuli coaxial with the axis of ratation of the Earth and determining temproal fluctuations in the axial component of angular memonetum of each annulus under the assumption of iso-rotation on cylindrical surfaces.

Strength of a Ceramic Sectored Flexure Specimen

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

Wereszczak, Andrew A; Duffy, Stephen F; Baker, E. H.

2008-01-01

A new test specimen, defined here as the "sectored flexure strength specimen", was developed to measure the strength of ceramic tubes specifically for circumstances when flaws located at the tube's outer diameter are the strength-limiter and subjected to axial tension. The understanding of such strength-limitation is relevant for when ceramic tubes are subjected to bending or when the internal temperature is hotter than the tube's exterior (e.g., heat exchangers). The specimen is both economically and statistically attractive because eight specimens (eight in the case of this project - but the user is not necessarily limited to eight) were extracted outmore » of each length of tube. An analytic expression for maximum or failure stress, and relationships portraying effective area and effective volume as a function of Weibull modulus were developed. Lastly, it was proven from the testing of two ceramics that the sectored flexure specimen was very effective at producing failures caused by strength-limiting flaws located on the tube's original outer diameter. Keywords: ceramics, strength, sectored flexure specimen, effective area, effective volume, finite-element analysis, Weibull distribution, and fractography.« less

Oxygen saturation in optic nerve head structures by hyperspectral image analysis.

PubMed

Beach, James; Ning, Jinfeng; Khoobehi, Bahram

2007-02-01

A method is presented for the calculation and visualization of percent blood oxygen saturation from specific tissue structures in hyperspectral images of the optic nerve head (ONH). Trans-pupillary images of the primate optic nerve head and overlying retinal blood vessels were obtained with a hyperspectral imaging (HSI) system attached to a fundus camera. Images were recorded during normal blood flow and after partially interrupting flow to the ONH and retinal circulation by elevation of the intraocular pressure (IOP) from 10 mmHg to 55 mmHg in steps. Percent oxygen saturation was calculated from groups of pixels associated with separate tissue structures, using a linear least-squares curve fit of the recorded hemoglobin spectrum to reference spectra obtained from fully oxygenated and deoxygenated red cell suspensions. Color maps of saturation were obtained from a new algorithm that enables comparison of oxygen saturation from large vessels and tissue areas in hyperspectral images. Percent saturation in retinal vessels and from the average over ONH structures (IOP = 10 mmHg) was (mean +/- SE): artery 81.8 +/- 0.4%, vein 42.6 +/- 0.9%, average ONH 68.3 +/- 0.4%. Raising IOP from 10 mmHg to 55 mmHg for 5 min caused blood oxygen saturation to decrease (mean +/- SE): artery 46.1 +/- 6.2%, vein 36.1 +/- 1.6%, average ONH 41.9 +/- 1.6%. The temporal cup showed the highest saturation at low and high IOP (77.3 +/- 1.0% and 60.1 +/- 4.0%) and the least reduction in saturation at high IOP (22.3%) compared with that of the average ONH (38.6%). A linear relationship was found between saturation indices obtained from the algorithm and percent saturation values obtained by spectral curve fits to calibrated red cell samples. Percent oxygen saturation was determined from hyperspectral images of the ONH tissue and retinal vessels overlying the ONH at normal and elevated IOP. Pressure elevation was shown to reduce blood oxygen saturation in vessels and ONH structures, with the smallest reduction in the ONH observed in the temporal cup. IOP-induced saturation changes were visualized in color maps using an algorithm that follows saturation-dependent changes in the blood spectrum and blood volume differences across tissue. Reduced arterial saturation at high IOP may have resulted from a flow-dependent mechanism.

Digital computer program for nuclear reactor design water properties (LWBR Development Program)

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

Lynn, L.L.

1967-07-01

An edit program MO899 for the tabulation of thermodynamic and transport properties of liquid and vapor water, frequently used in design calculations for pressurized water nuclear reactors, is described. The data tabulated are obtained from a FORTRAN IV subroutine named HOH. Values of enthalpy, specific volume, viscosity, and thermal conductivity are given for the following ranges: pressure from one bar (14.5 psia) to 175 bars (2538 psia) and temperature from as much as 320 deg C (608 deg F) below saturation up to 500 deg C (932 deg F) above saturation. (NSA 21: 38472)

Theranostic multimodular potential of zinc-doped ferrite-saturated metal-binding protein-loaded novel nanocapsules in cancers

PubMed Central

Kamalapuram, Sishir K; Kanwar, Rupinder K; Roy, Kislay; Chaudhary, Rajneesh; Sehgal, Rakesh; Kanwar, Jagat R

2016-01-01

The present study successfully developed orally deliverable multimodular zinc (Zn) iron oxide (Fe3O4)-saturated bovine lactoferrin (bLf)-loaded polymeric nanocapsules (NCs), and evaluated their theranostic potential (antitumor efficacy, magnetophotothermal efficacy and imaging capability) in an in vivo human xenograft CpG-island methylator phenotype (CIMP)-1+/CIMP2−/chromosome instability-positive colonic adenocarcinoma (Caco2) and claudin-low, triple-negative (ER−/PR−/HER2−; MDA-MB-231) breast cancer model. Mice fed orally on the Zn-Fe-bLf NC diet showed downregulation in tumor volume and complete regression in tumor volume after 45 days of feeding. In human xenograft colon cancer, vehicle-control NC diet-group (n=5) mice showed a tumor volume of 52.28±11.55 mm3, and Zn-Fe-bLf NC diet (n=5)-treated mice had a tumor-volume of 0.10±0.073 mm3. In the human xenograft breast cancer model, Zn-Fe-bLf NC diet (n=5)-treated mice showed a tumor volume of 0.051±0.062 mm3 within 40 days of feeding. Live mouse imaging conducted by near-infrared fluorescence imaging of Zn-Fe-bLf NCs showed tumor site-specific localization and regression of colon and breast tumor volume. Ex vivo fluorescence-imaging analysis of the vital organs of mice exhibited sparse localization patterns of Zn-Fe-bLf NCs and also confirmed tumor-specific selective localization patterns of Zn-Fe-bLf NCs. Dual imaging using magnetic resonance imaging and computerized tomography scans revealed an unprecedented theranostic ability of the Zn-Fe-bLf NCs. These observations warrant consideration of multimodular Zn-Fe-bLf NCs for real-time cancer imaging and simultaneous cancer-targeted therapy. PMID:27099495

Impulse Magnetization of Nd-Fe-B Sintered Magnets for Sensors

PubMed Central

Przybylski, Marek; Kapelski, Dariusz; Ślusarek, Barbara; Wiak, Sławomir

2016-01-01

Magnetization of large Nd-Fe-B sintered permanent magnets is still challenging. This type of permanent magnet is electrically conductive, so impulse magnetization causes a flow of eddy currents which prevent magnetization of the whole volume of the magnet. The paper deals with the impulse magnetization of sintered Nd-Fe-B permanent magnets and shows a method for the determination of suitable parameters for the supply system. The necessary magnetic field strength for magnetization of the magnet to saturation was determined. The optimal magnetizing fixture supply voltage for magnetization to saturation was determined from simulations in PSpice software, finite element analyses in Maxwell 15 and measurements. Measurements of magnetic induction on the surface of the Nd-Fe-B magnet are also presented to ensure that a magnet with 70 mm diameter and 20 mm in height is fully saturated. PMID:27110783

Bubble performance of a novel dissolved air flotation(DAF) unit.

PubMed

Chen, Fu-tai; Peng, Feng-xian; Wu, Xiao-qing; Luan, Zhao-kun

2004-01-01

ES-DAF, a novel DAF with low cost, high reliability and easy controllability, was studied. Without a costly air saturator, ES-DAF consists of an ejector and a static mixer between the pressure side and suction side of the recycle rotary pump. The bubble size distribution in this novel unit was studied in detail by using a newly developed CCD imagination through a microscope. Compared with M-DAF under the same saturation pressure, ES-DAF can produce smaller bubble size and higher bubble volume concentration, especially in lower pressure. In addition, the bubble size decreases with the increase of reflux ratio or decrease of superficial air-water ratio. These results suggested that smaller bubbles will be formed when the initial number of nucleation sites increases by enhancing the turbulence intensity in the saturation system.

Impulse Magnetization of Nd-Fe-B Sintered Magnets for Sensors.

PubMed

Przybylski, Marek; Kapelski, Dariusz; Ślusarek, Barbara; Wiak, Sławomir

2016-04-21

Magnetization of large Nd-Fe-B sintered permanent magnets is still challenging. This type of permanent magnet is electrically conductive, so impulse magnetization causes a flow of eddy currents which prevent magnetization of the whole volume of the magnet. The paper deals with the impulse magnetization of sintered Nd-Fe-B permanent magnets and shows a method for the determination of suitable parameters for the supply system. The necessary magnetic field strength for magnetization of the magnet to saturation was determined. The optimal magnetizing fixture supply voltage for magnetization to saturation was determined from simulations in PSpice software, finite element analyses in Maxwell 15 and measurements. Measurements of magnetic induction on the surface of the Nd-Fe-B magnet are also presented to ensure that a magnet with 70 mm diameter and 20 mm in height is fully saturated.

WE-AB-204-03: A Novel 3D Printed Phantom for 4D PET/CT Imaging and SIB Radiotherapy Verification

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

Soultan, D; Murphy, J; Moiseenko, V

Purpose: To construct and test a 3D printed phantom designed to mimic variable PET tracer uptake seen in lung tumor volumes. To assess segmentation accuracy of sub-volumes of the phantom following 4D PET/CT scanning with ideal and patient-specific respiratory motion. To plan, deliver and verify delivery of PET-driven, gated, simultaneous integrated boost (SIB) radiotherapy plans. Methods: A set of phantoms and inserts were designed and manufactured for a realistic representation of lung cancer gated radiotherapy steps from 4D PET/CT scanning to dose delivery. A cylindrical phantom (40x 120 mm) holds inserts for PET/CT scanning. The novel 3D printed insert dedicatedmore » to 4D PET/CT mimics high PET tracer uptake in the core and lower uptake in the periphery. This insert is a variable density porous cylinder (22.12×70 mm), ABS-P430 thermoplastic, 3D printed by uPrint SE Plus with inner void volume (5.5×42 mm). The square pores (1.8×1.8 mm2 each) fill 50% of outer volume, resulting in a 2:1 SUV ratio of PET-tracer in the void volume with respect to porous volume. A matching in size cylindrical phantom is dedicated to validate gated radiotherapy. It contains eight peripheral holes matching the location of the porous part of the 3D printed insert, and one central hole. These holes accommodate adaptors for Farmer-type ion chamber and cells vials. Results: End-to-end test were performed from 4D PET/CT scanning to transferring data to the planning system and target volume delineation. 4D PET/CT scans were acquired of the phantom with different respiratory motion patterns and gating windows. A measured 2:1 18F-FDG SUV ratio between inner void and outer volume matched the 3D printed design. Conclusion: The novel 3D printed phantom mimics variable PET tracer uptake typical of tumors. Obtained 4D PET/CT scans are suitable for segmentation, treatment planning and delivery in SIB gated treatments of NSCLC.« less

Sulfur Saturation Limits in Silicate Melts and their Implications for Core Formation Scenarios for Terrestrial Planets

NASA Technical Reports Server (NTRS)

Holzheid, Astrid; Grove, Timothy L.

2002-01-01

This study explores the controls of temperature, pressure, and silicate melt composition on S solubility in silicate liquids. The solubility of S in FeO-containing silicate melts in equilibrium with metal sulfide increases significantly with increasing temperature but decreases with increasing pressure. The silicate melt structure also exercises a control on S solubility. Increasing the degree of polymerization of the silicate melt structure lowers the S solubility in the silicate liquid. The new set of experimental data is used to expand the model of Mavrogenes and O'Neill(1999) for S solubility in silicate liquids by incorporating the influence of the silicate melt structure. The expected S solubility in the ascending magma is calculated using the expanded model. Because the negative pressure dependence of S solubility is more influential than the positive temperature dependence, decompression and adiabatic ascent of a formerly S-saturated silicate magma will lead to S undersaturation. A primitive magma that is S-saturated in its source region will, therefore, become S-undersaturated as it ascends to shallower depth. In order to precipitate magmatic sulfides, the magma must first cool and undergo fractional crystallization to reach S saturation. The S content in a metallic liquid that is in equilibrium with a magma ocean that contains approx. 200 ppm S (i.e., Earth's bulk mantle S content) ranges from 5.5 to 12 wt% S. This range of S values encompasses the amount of S (9 to 12 wt%) that would be present in the outer core if S is the light element. Thus, the Earth's proto-mantle could be in equilibrium (in terms of the preserved S abundance) with a core-forming metallic phase.

Gauging a Hydrocarbon Ruler by an Intrinsic Exciton Probe†

PubMed Central

Khan, M. Adil; Neale, Chris; Michaux, Catherine; Pomés, Régis; Privé, Gilbert G.; Woody, Robert W.; Bishop, Russell E.

2016-01-01

The structural basis of lipid acyl-chain selection by membrane-intrinsic enzymes is poorly understood because most integral membrane enzymes of lipid metabolism have proven refractory to structure determination; however, robust enzymes from the outer membranes of Gram-negative bacteria are now providing a first glimpse at the underlying mechanisms. The methylene unit resolution of the phospholipid: lipid A palmitoyltransferase PagP is determined by the hydrocarbon ruler, a 16-carbon saturated acyl-chain-binding pocket buried within the transmembrane β-barrel structure. Substitution of Gly88 lining the floor of the hydrocarbon ruler with Ala or Met makes the enzyme select specifically 15- or 12-carbon saturated acyl chains, respectively, indicating that hydrocarbon ruler depth determines acyl-chain selection. However, the Gly88Cys PagP resolution does not diminish linearly because it selects both 14- and 15-carbon saturated acyl chains. We discovered that an exciton, emanating from a buried Tyr26–Trp66 phenol–indole interaction, is extinguished by a local structural perturbation arising from the proximal Gly88Cys PagP sulfhydryl group. Site-specific S-methylation of the single Cys afforded Gly88Cys-S-methyl PagP, which reasserted both the exciton and methylene unit resolution by specifically selecting 13-carbon saturated acyl chains for transfer to lipid A. Unlike the other Gly88 substitutions, the Cys sulfhydryl group recedes from the hydrocarbon ruler floor and locally perturbs the subjacent Tyr26 and Trp66 aromatic rings. The resulting hydrocarbon ruler expansion thus occurs at the exciton’s expense and accommodates an extra methylene unit in the selected acyl chain. The hydrocarbon ruler–exciton juxtaposition endows PagP with a molecular gauge for probing the structural basis of lipid acyl-chain selection in a membrane-intrinsic environment. PMID:17375935

Low-(18)O Silicic Magmas: Why Are They So Rare?

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

Balsley, S.D.; Gregory, R.T.

1998-10-15

LOW-180 silicic magmas are reported from only a small number of localities (e.g., Yellowstone and Iceland), yet petrologic evidence points to upper crustal assimilation coupled with fractional crystallization (AFC) during magma genesis for nearly all silicic magmas. The rarity of 10W-l `O magmas in intracontinental caldera settings is remarkable given the evidence of intense 10W-l*O meteoric hydrothermal alteration in the subvolcanic remnants of larger caldera systems. In the Platoro caldera complex, regional ignimbrites (150-1000 km3) have plagioclase 6180 values of 6.8 + 0.1%., whereas the Middle Tuff, a small-volume (est. 50-100 km3) post-caldera collapse pyroclastic sequence, has plagioclase 8]80 valuesmore » between 5.5 and 6.8%o. On average, the plagioclase phenocrysts from the Middle Tuff are depleted by only 0.3%0 relative to those in the regional tuffs. At Yellowstone, small-volume post-caldera collapse intracaldera rhyolites are up to 5.5%o depleted relative to the regional ignimbrites. Two important differences between the Middle Tuff and the Yellowstone 10W-180 rhyolites elucidate the problem. Middle Tuff magmas reached water saturation and erupted explosively, whereas most of the 10W-l 80 Yellowstone rhyolites erupted effusively as domes or flows, and are nearly devoid of hydrous phenocrysts. Comparing the two eruptive types indicates that assimilation of 10W-180 material, combined with fractional crystallization, drives silicic melts to water oversaturation. Water saturated magmas either erupt explosively or quench as subsurface porphyrins bejiire the magmatic 180 can be dramatically lowered. Partial melting of low- 180 subvolcanic rocks by near-anhydrous magmas at Yellowstone produced small- volume, 10W-180 magmas directly, thereby circumventing the water saturation barrier encountered through normal AFC processes.« less

EXPERIMENTAL INVESTIGATION OF RELATIVE PERMEABILITY UPSCALING FROM THE MICRO-SCALE TO THE MACRO-SCALE

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

Laura J. Pyrak-Nolte; Nicholas J. Giordano; David D. Nolte

2004-03-01

The principal challenge of upscaling techniques for multi-phase fluid dynamics in porous media is to determine which properties on the micro-scale can be used to predict macroscopic flow and spatial distribution of phases at core- and field-scales. The most notable outcome of recent theories is the identification of interfacial areas per volume for multiple phases as a fundamental parameter that determines much of the multi-phase properties of the porous medium. A formal program of experimental research was begun to directly test upscaling theories in fluid flow through porous media by comparing measurements of relative permeability and capillary-saturation with measurements ofmore » interfacial area per volume. This project on the experimental investigation of relative permeability upscaling has produced a unique combination of three quite different technical approaches to the upscaling problem of obtaining pore-related microscopic properties and using them to predict macroscopic behavior. Several important ''firsts'' have been achieved during the course of the project. (1) Optical coherence imaging, a laser-based ranging and imaging technique, has produced the first images of grain and pore structure up to 1 mm beneath the surface of the sandstone and in a laboratory borehole. (2) Woods metal injection has connected for the first time microscopic pore-scale geometric measurements with macroscopic saturation in real sandstone cores. (3) The micro-model technique has produced the first invertible relationship between saturation and capillary pressure--showing that interfacial area per volume (IAV) provides the linking parameter. IAV is a key element in upscaling theories, so this experimental finding may represent the most important result of this project, with wide ramifications for predictions of fluid behavior in porous media.« less

The nutrient content of US household food purchases by store types

PubMed Central

Stern, Dalia; Ng, Shu Wen; Popkin, Barry M

2015-01-01

Introduction Little is known about where households shop for packaged foods, what foods and beverages they purchase, and the nutrient content of these purchases. The objectives are to describe volume trends and nutrient content (food groups and nutrient profiles) of household packaged foods purchases (PFP) by store-type. Methods Cross-sectional analysis of US households’ food purchases (Nielsen Homescan) from 2000 to 2012 (n=652,023 household-year observations) with survey weights used for national representativeness. Household PFP trends (% volume) by store-type, household purchases of key food and beverage groups based on caloric contribution by store-type, and mean caloric and nutrient densities (sugars, saturated fat and sodium) of household PFP by store-type are analyzed. Data were collected from 2000–2012. Analyses were conducted in 2014–2015. Results The proportion of total volume of household PFP significantly increased from 2000 to 2012 for mass-merchandisers (13.1 to 23.9%), convenience-stores (3.6 to 5.9%) and warehouse-club (6.2 to 9.8%), and significantly decreased for grocery-chains (58.5 to 46.3%) and non-chain grocerys (10.3 to 5.2%). Top common sources of calories (%) from household PFP by food/beverage group include: savory snacks, grain-based desserts and regular soft-drinks. The energy, total sugar, sodium and saturated fat densities of household PFP from mass-merchandisers, warehouse-club and convenience-stores were higher, compared to grocery-stores. Conclusions PFP from stores with poorer nutrient density (more energy, total sugar, sodium and saturated fat-dense), such as warehouse-club, mass-merchandisers and convenience-stores are growing, representing a potential US public health concern. PMID:26437868

Computed Tomographic Measures of Pulmonary Vascular Morphology in Smokers and Their Clinical Implications

PubMed Central

Estépar, Raúl San José; Kinney, Gregory L.; Black-Shinn, Jennifer L.; Bowler, Russell P.; Kindlmann, Gordon L.; Ross, James C.; Kikinis, Ron; Han, MeiLan K.; Come, Carolyn E.; Diaz, Alejandro A.; Cho, Michael H.; Hersh, Craig P.; Schroeder, Joyce D.; Reilly, John J.; Lynch, David A.; Crapo, James D.; Wells, J. Michael; Dransfield, Mark T.; Hokanson, John E.

2013-01-01

Rationale: Angiographic investigation suggests that pulmonary vascular remodeling in smokers is characterized by distal pruning of the blood vessels. Objectives: Using volumetric computed tomography scans of the chest we sought to quantitatively evaluate this process and assess its clinical associations. Methods: Pulmonary vessels were automatically identified, segmented, and measured. Total blood vessel volume (TBV) and the aggregate vessel volume for vessels less than 5 mm2 (BV5) were calculated for all lobes. The lobe-specific BV5 measures were normalized to the TBV of that lobe and the nonvascular tissue volume (BV5/TissueV) to calculate lobe-specific BV5/TBV and BV5/TissueV ratios. Densitometric measures of emphysema were obtained using a Hounsfield unit threshold of −950 (%LAA-950). Measures of chronic obstructive pulmonary disease severity included single breath measures of diffusing capacity of carbon monoxide, oxygen saturation, the 6-minute-walk distance, St George’s Respiratory Questionnaire total score (SGRQ), and the body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index. Measurements and Main Results: The %LAA-950 was inversely related to all calculated vascular ratios. In multivariate models including age, sex, and %LAA-950, lobe-specific measurements of BV5/TBV were directly related to resting oxygen saturation and inversely associated with both the SGRQ and BODE scores. In similar multivariate adjustment lobe-specific BV5/TissueV ratios were inversely related to resting oxygen saturation, diffusing capacity of carbon monoxide, 6-minute-walk distance, and directly related to the SGRQ and BODE. Conclusions: Smoking-related chronic obstructive pulmonary disease is characterized by distal pruning of the small blood vessels (<5 mm2) and loss of tissue in excess of the vasculature. The magnitude of these changes predicts the clinical severity of disease. PMID:23656466

Microwave Limb Sounder Measurements Depicting the Relationship Between Nitrous Oxide Levels and

NASA Technical Reports Server (NTRS)

2005-01-01

Aura's Microwave Limb Sounder measures nitrous oxide, which is unaffected by stratospheric chemical processes. By studying changes in its levels, scientists can better understand how air is moving around and how ozone is affected by that air motion, allowing them to differentiate those changes from the ones caused by chemical ozone destruction. In these cross-sections of nitrous oxide (top) and ozone (bottom) data from Aura, changes in the levels of these two chemicals at various temperatures and latitudes are depicted over time. The white contour shows the approximate location of the polar vortex boundary.

The left panel data were collected on January 23, 2005, near the beginning of chemical ozone destruction this winter. Virtually all chemical loss occurred before March 10 (center panel). Ozone destruction extended throughout the polar vortex from about 15-20 kilometers (9-13 miles), but occurred only in the outer part of the vortex from 20-25 kilometers (13-16 miles). The differences between the two days are depicted in the right panel. The largest observed difference is about a 1.2 parts per million by volume decrease in ozone. Plots of nitrous oxide show a decrease in the region in the outer part of the vortex where most ozone loss occurs, indicating that air from above (where nitrous oxide is lower) has moved into this region. This downward motion brings higher ozone into the region where chemical loss is occurring, thus partially masking the effects of chemical loss. Calculations using Microwave Limb Sounder data to separate dynamical and chemical effects indicate maximum chemical ozone loss of approximately 2 parts per million by volume (approximately 60 percent) in the outer part of the vortex near 18-21 kilometers (11-13 miles), and approximately 1.5 parts per million by volume when averaged throughout the whole vortex region.

Linear models for sound from supersonic reacting mixing layers

NASA Astrophysics Data System (ADS)

Chary, P. Shivakanth; Samanta, Arnab

2016-12-01

We perform a linearized reduced-order modeling of the aeroacoustic sound sources in supersonic reacting mixing layers to explore their sensitivities to some of the flow parameters in radiating sound. Specifically, we investigate the role of outer modes as the effective flow compressibility is raised, when some of these are expected to dominate over the traditional Kelvin-Helmholtz (K-H) -type central mode. Although the outer modes are known to be of lesser importance in the near-field mixing, how these radiate to the far-field is uncertain, on which we focus. On keeping the flow compressibility fixed, the outer modes are realized via biasing the respective mean densities of the fast (oxidizer) or slow (fuel) side. Here the mean flows are laminar solutions of two-dimensional compressible boundary layers with an imposed composite (turbulent) spreading rate, which we show to significantly alter the growth of instability waves by saturating them earlier, similar to in nonlinear calculations, achieved here via solving the linear parabolized stability equations. As the flow parameters are varied, instability of the slow modes is shown to be more sensitive to heat release, potentially exceeding equivalent central modes, as these modes yield relatively compact sound sources with lesser spreading of the mixing layer, when compared to the corresponding fast modes. In contrast, the radiated sound seems to be relatively unaffected when the mixture equivalence ratio is varied, except for a lean mixture which is shown to yield a pronounced effect on the slow mode radiation by reducing its modal growth.

The quantitative assessment of peri-implant bone responses using histomorphometry and micro-computed tomography.

PubMed

Schouten, Corinne; Meijer, Gert J; van den Beucken, Jeroen J J P; Spauwen, Paul H M; Jansen, John A

2009-09-01

In the present study, the effects of implant design and surface properties on peri-implant bone response were evaluated with both conventional histomorphometry and micro-computed tomography (micro-CT), using two geometrically different dental implants (Screw type, St; Push-in, Pi) either or not surface-modified (non-coated, CaP-coated, or CaP-coated+TGF-beta1). After 12 weeks of implantation in a goat femoral condyle model, peri-implant bone response was evaluated in three different zones (inner: 0-500 microm; middle: 500-1000 microm; and outer: 1000-1500 microm) around the implant. Results indicated superiority of conventional histomorphometry over micro-CT, as the latter is hampered by deficits in the discrimination at the implant/tissue interface. Beyond this interface, both analysis techniques can be regarded as complementary. Histomorphometrical analysis showed an overall higher bone volume around St compared to Pi implants, but no effects of surface modification were observed. St implants showed lowest bone volumes in the outer zone, whereas inner zones were lowest for Pi implants. These results implicate that for Pi implants bone formation started from two different directions (contact- and distance osteogenesis). For St implants it was concluded that undersized implantation technique and loosening of bone fragments compress the zones for contact and distant osteogenesis, thereby improving bone volume at the interface significantly.

Strength Estimation for Hydrate-Bearing Sediments From Direct Shear Tests of Hydrate-Bearing Sand and Silt

NASA Astrophysics Data System (ADS)

Liu, Zhichao; Dai, Sheng; Ning, Fulong; Peng, Li; Wei, Houzhen; Wei, Changfu

2018-01-01

Safe and economic methane gas production, as well as the replacement of methane while sequestering carbon in natural hydrate deposits, requires enhanced geomechanical understanding of the strength and volume responses of hydrate-bearing sediments during shear. This study employs a custom-made apparatus to investigate the mechanical and volumetric behaviors of carbon dioxide hydrate-bearing sediments subjected to direct shear. The results show that both peak and residual strengths increase with increased hydrate saturation and vertical stress. Hydrate contributes mainly the cohesion and dilatancy constraint to the peak strength of hydrate-bearing sediments. The postpeak strength reduction is more evident and brittle in specimens with higher hydrate saturation and under lower stress. Significant strength reduction after shear failure is expected in silty sediments with high hydrate saturation Sh ≥ 0.65. Hydrate contribution to the residual strength is mainly by increasing cohesion at low hydrate saturation and friction at high hydrate saturation. Stress state and hydrate saturation are dominating both the stiffness and the strength of hydrate-bearing sediments; thus, a wave velocity-based peak strength prediction model is proposed and validated, which allows for precise estimation of the shear strength of hydrate-bearing sediments through acoustic logging data. This method is advantageous to geomechanical simulators, particularly when the experimental strength data of natural samples are not available.

Effects of Simulated Pathophysiology on the Performance of a Decision Support Medical Monitoring System for Early Detection of Hemodynamic Decompensation in Humans

DTIC Science & Technology

2015-10-01

Arterial oxygen saturation was monitored 130 using a finger pulse oximeter and end-tidal CO2 (ETCO2) was collected from a nasal cannula 131 (Cardiocap/5...Johnson et al, J Appl Physiol 2014 PMID 24876357. 5 Keywords Trauma, coagulation, central venous pressure, stroke volume, pulse pressure...Johnson BD, Curry TB, Convertino VA, & Joyner MJ. The association between pulse pressure and stroke volume during lower body negative pressure and

Determination of the Average Native Background and the Light-Induced EPR Signals and their Variation in the Teeth Enamel Based on Large-Scale Survey of the Population.

PubMed

Ivannikov, Alexander I; Khailov, Artem M; Orlenko, Sergey P; Skvortsov, Valeri G; Stepanenko, Valeri F; Zhumadilov, Kassym Sh; Williams, Benjamin B; Flood, Ann B; Swartz, Harold M

2016-12-01

The aim of the study is to determine the average intensity and variation of the native background signal amplitude (NSA) and of the solar light-induced signal amplitude (LSA) in electron paramagnetic resonance (EPR) spectra of tooth enamel for different kinds of teeth and different groups of people. These values are necessary for determination of the intensity of the radiation-induced signal amplitude (RSA) by subtraction of the expected NSA and LSA from the total signal amplitude measured in L-band for in vivo EPR dosimetry. Variation of these signals should be taken into account when estimating the uncertainty of the estimated RSA. A new analysis of several hundred EPR spectra that were measured earlier at X-band in a large-scale examination of the population of the Central Russia was performed. Based on this analysis, the average values and the variation (standard deviation, SD) of the amplitude of the NSA for the teeth from different positions, as well as LSA in outer enamel of the front teeth for different population groups, were determined. To convert data acquired at X-band to values corresponding to the conditions of measurement at L-band, the experimental dependencies of the intensities of the RSA, LSA and NSA on the m.w. power, measured at both X and L-band, were analysed. For the two central upper incisors, which are mainly used in in vivo dosimetry, the mean LSA annual rate induced only in the outer side enamel and its variation were obtained as 10 ± 2 (SD = 8) mGy y -1 , the same for X- and L-bands (results are presented as the mean ± error of mean). Mean NSA in enamel and its variation for the upper incisors was calculated at 2.0 ± 0.2 (SD = 0.5) Gy, relative to the calibrated RSA dose-response to gamma radiation measured under non-power saturation conditions at X-band. Assuming the same value for L-band under non-power saturating conditions, then for in vivo measurements at L-band at 25 mW (power saturation conditions), a mean NSA and its variation correspond to 4.0 ± 0.4 (SD = 1.0) Gy. © Crown copyright 2016.

Determination of the Average Native Background and the Light-Induced EPR Signals and their Variation in the Teeth Enamel Based on Large-Scale Survey of the Population

PubMed Central

Ivannikov, Alexander I.; Khailov, Artem M.; Orlenko, Sergey P.; Skvortsov, Valeri G.; Stepanenko, Valeri F.; Zhumadilov, Kassym Sh.; Williams, Benjamin B.; Flood, Ann B.; Swartz, Harold M.

2016-01-01

The aim of the study is to determine the average intensity and variation of the native background signal amplitude (NSA) and of the solar light-induced signal amplitude (LSA) in electron paramagnetic resonance (EPR) spectra of tooth enamel for different kinds of teeth and different groups of people. These values are necessary for determination of the intensity of the radiation-induced signal amplitude (RSA) by subtraction of the expected NSA and LSA from the total signal amplitude measured in L-band for in vivo EPR dosimetry. Variation of these signals should be taken into account when estimating the uncertainty of the estimated RSA. A new analysis of several hundred EPR spectra that were measured earlier at X-band in a large-scale examination of the population of the Central Russia was performed. Based on this analysis, the average values and the variation (standard deviation, SD) of the amplitude of the NSA for the teeth from different positions, as well as LSA in outer enamel of the front teeth for different population groups, were determined. To convert data acquired at X-band to values corresponding to the conditions of measurement at L-band, the experimental dependencies of the intensities of the RSA, LSA and NSA on the m.w. power, measured at both X and L-band, were analysed. For the two central upper incisors, which are mainly used in in vivo dosimetry, the mean LSA annual rate induced only in the outer side enamel and its variation were obtained as 10 ± 2 (SD = 8) mGy y−1, the same for X- and L-bands (results are presented as the mean ± error of mean). Mean NSA in enamel and its variation for the upper incisors was calculated at 2.0 ± 0.2 (SD = 0.5) Gy, relative to the calibrated RSA dose–response to gamma radiation measured under non-power saturation conditions at X-band. Assuming the same value for L-band under non-power saturating conditions, then for in vivo measurements at L-band at 25 mW (power saturation conditions), a mean NSA and its variation correspond to 4.0 ± 0.4 (SD = 1.0) Gy. PMID:27412516

20 CFR Appendix B to Part 718 - Standards for Administration and Interpretation of Pulmonary Function Tests. Tables B1, B2, B3...

Code of Federal Regulations, 2013 CFR

2013-04-01

... user of the instrument must have a means of correcting volumes to body temperature saturated with water vapor (BTPS) under conditions of varying ambient spirometer temperatures and barometric pressures. (v...

20 CFR Appendix B to Part 718 - Standards for Administration and Interpretation of Pulmonary Function Tests. Tables B1, B2, B3...

Code of Federal Regulations, 2014 CFR

2014-04-01

... user of the instrument must have a means of correcting volumes to body temperature saturated with water vapor (BTPS) under conditions of varying ambient spirometer temperatures and barometric pressures. (v...

20 CFR Appendix B to Part 718 - Standards for Administration and Interpretation of Pulmonary Function Tests. Tables B1, B2, B3...

Code of Federal Regulations, 2012 CFR

2012-04-01

... user of the instrument must have a means of correcting volumes to body temperature saturated with water vapor (BTPS) under conditions of varying ambient spirometer temperatures and barometric pressures. (v...

RECOVERY OF METAL VALUES FROM AQUEOUS SOLUTIONS BY SOLVENT EXTRACTION

DOEpatents

Moore, R.L.

1959-09-01

An organic solvent mixure is described for extracting actinides from aqueous solutions; the solvent mixture consists of from 10 to 25% by volume of tributyl phosphate and the remainder a chlorine-fluorine-substituted saturated hydrocarbon having two carbon atoms in the molecule.

Retinal oxygen saturation evaluation by multi-spectral fundus imaging

NASA Astrophysics Data System (ADS)

Khoobehi, Bahram; Ning, Jinfeng; Puissegur, Elise; Bordeaux, Kimberly; Balasubramanian, Madhusudhanan; Beach, James

2007-03-01

Purpose: To develop a multi-spectral method to measure oxygen saturation of the retina in the human eye. Methods: Five Cynomolgus monkeys with normal eyes were anesthetized with intramuscular ketamine/xylazine and intravenous pentobarbital. Multi-spectral fundus imaging was performed in five monkeys with a commercial fundus camera equipped with a liquid crystal tuned filter in the illumination light path and a 16-bit digital camera. Recording parameters were controlled with software written specifically for the application. Seven images at successively longer oxygen-sensing wavelengths were recorded within 4 seconds. Individual images for each wavelength were captured in less than 100 msec of flash illumination. Slightly misaligned images of separate wavelengths due to slight eye motion were registered and corrected by translational and rotational image registration prior to analysis. Numerical values of relative oxygen saturation of retinal arteries and veins and the underlying tissue in between the artery/vein pairs were evaluated by an algorithm previously described, but which is now corrected for blood volume from averaged pixels (n > 1000). Color saturation maps were constructed by applying the algorithm at each image pixel using a Matlab script. Results: Both the numerical values of relative oxygen saturation and the saturation maps correspond to the physiological condition, that is, in a normal retina, the artery is more saturated than the tissue and the tissue is more saturated than the vein. With the multi-spectral fundus camera and proper registration of the multi-wavelength images, we were able to determine oxygen saturation in the primate retinal structures on a tolerable time scale which is applicable to human subjects. Conclusions: Seven wavelength multi-spectral imagery can be used to measure oxygen saturation in retinal artery, vein, and tissue (microcirculation). This technique is safe and can be used to monitor oxygen uptake in humans. This work is original and is not under consideration for publication elsewhere.

Theoretical and numerical aspects of fluid-saturated elasto-plastic soils

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

Ehlers, W.

1995-12-31

The theoretical and numerical treatment of fluid-saturated porous solid materials generally falls into the category of porous media models, which are described within the framework of the classical theory of mixtures extended by the concept of volume fractions (porous media theories). In particular, this concept allows for the description of saturated, unsaturated and empty porous matrix materials, thus offering a well-founded theoretical background for a lot of engineering problems occurring, for instance, in the fields of geomechanics (soil and rock mechanics as well as glacier and rock ice mechanics), oil producing industries, sintering technologies, biomechanics, etc. In the present contribution,more » theoretical and numerical studies are outlined to describe a two-phase material composed of an incompressible elasto-plastic soil matrix saturated by an incompressible viscous pore fluid. In this context, the phenomenon of phase incompressibility is well known as a microscopic effect not implying bulk incompressibility in the macro regime. This is seen from the fact that even if the material density functions of the individual constituents are constant during deformation, the corresponding bulk densities can still change through changes in the volume fractions. Within the framework of a pure mechanical theory, constitutive equations are given for both the solid and the fluid partial stress tensors and for the interaction force acting between the two materials. Concerning the porous soil matrix, the elastic properties are described by an elasticity law of Hookean type, while the plastic range is governed by a {open_quote}single surface{close_quote} yield function exhibiting a smooth and closed shape in the principal stress space together with a non-associated flow rule. The viscosity effects of the pore fluid are included in the fluid stress tensor and in the drag force.« less

Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

NASA Astrophysics Data System (ADS)

Kyriacou, P. A.; Shafqat, K.; Pal, S. K.

2007-10-01

Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO2) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO2) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse oximeters showed gradual decrease of saturations during induced hypoperfusion which demonstrate the direct relation between blood volumes (PPG amplitudes), arterial vessel stenosis and blood oxygen saturation. The custom made pulse oximeter was found to be more sensitive to SpO2 changes than the commercial pulse oximeter especially at high occluding pressures.

Quantifying Hydrate Formation in Gas-rich Environments Using the Method of Characteristics

NASA Astrophysics Data System (ADS)

You, K.; Flemings, P. B.; DiCarlo, D. A.

2015-12-01

Methane hydrates hold a vast amount of methane globally, and have huge energy potential. Methane hydrates in gas-rich environments are the most promising production targets. We develop a one-dimensional analytical solution based on the method of characteristics to explore hydrate formation in such environments (Figure 1). Our solution shows that hydrate saturation is constant with time and space in a homogeneous system. Hydrate saturation is controlled by the initial thermodynamic condition of the system, and changed by the gas fractional flow. Hydrate saturation increases with the initial distance from the hydrate phase boundary. Different gas fractional flows behind the hydrate solidification front lead to different gas saturations at the hydrate solidification front. The higher the gas saturation at the front, the less the volume available to be filled by hydrate, and hence the lower the hydrate saturation. The gas fractional flow depends on the relative permeability curves, and the forces that drive the flow. Viscous forces (the drive for flow induced from liquid pressure gradient) dominate the flow, and hydrate saturation is independent on the gas supply rates and the flow directions at high gas supply rates. Hydrate saturation can be estimated as one minus the ratio of the initial to equilibrium salinity. Gravity forces (the drive for flow induced from the gravity) dominate the flow, and hydrate saturation depends on the flow rates and the flow directions at low gas supply rates. Hydrate saturation is highest for upward flow, and lowest for downward flow. Hydrate saturation decreases with the flow rate for upward flow, and increases with the flow rate for downward flow. This analytical solution illuminates how hydrate is formed by gas (methane, CO2, ethane, propane) flowing into brine-saturated sediments at both the laboratory and geological scales (Figure 1). It provides an approach to generalize the understanding of hydrate solidification in gas-rich environments, although complicated numerical models have been developed previously. Examples of gas expulsion into hydrate stability zones and the associated hydrate formation in both laboratory and geological scales, and CO2 sequestration into CO2-hydrates near the seafloor and under the permafrost will be presented.

Effect of the method of estimation of soil saturated hydraulic conductivity with regards to the design of stormwater infiltration trenches

NASA Astrophysics Data System (ADS)

Paiva coutinho, Artur; Predelus, Dieuseul; Lassabatere, Laurent; Ben Slimene, Erij; Celso Dantas Antonino, Antonio; Winiarski, Thierry; Joaquim da Silva Pereira Cabral, Jaime; Angulo-Jaramillo, Rafael

2014-05-01

Best management practices are based on the infiltration of stormwater (e.g. infiltration into basins or trenches) to reduce the risk of flooding of urban areas. Proper estimations of saturated hydraulic conductivity of the vadose zone are required to avoid inappropriate design of infiltration devices. This article aims at assessing (i) the method-dependency of the estimation of soils saturated hydraulic conductivity and (ii) the consequences of such dependency on the design of infiltration trenches. This is illustrated for the specific case of an infiltration trench to be constructed to receive stormwater from a specific parking surface, 250 m2 in area, in Recife (Brazil). Water infiltration experiments were conducted according to the Beerkan Method, i.e. application of a zero water pressure head through a disc source (D=15 cm) and measures of the amount of infiltrated water with time. Saturated hydraulic conductivity estimates are derived from the analysis of these infiltration tests using several different conceptual approaches: one-dimensional models of Horton(1933) and Philip(1957), three-dimensional methods recently developed (Lassabatere et al., 2006, Wu et al., 1999, and Bagarello et al., 2013) and direct 3-dimensional numerical inversion. The estimations for saturated hydraulic conductivity ranged between 65.5 mm/h and 94 mm/h for one-dimensional methods, whereas using three-dimensional methods saturated hydraulic conductivity ranged between 15.6 mm/h and 50 mm/h. These results shows the need for accounting for 3D geometry, and more generally, the physics of water infiltration in soils, if a proper characterization of soil saturated hydraulic conductivity is targeted. In a second step, each estimate of the saturated hydraulic conductivity was used to calculate the stormwater to be stored in the studied trench for several rainfall events of recurrence intervals of 2 to 25 years. The calculation of these volumes showed a great sensitivity with regards to the estimated values of saturated hydraulic conductivity. The designed volumes of the trench vary from 8.3 m3 to 15.9 m3 for one-dimensional methods and 11.9 m3 to 24.5 m3 for three-dimensional methods, respectively. The results show that any miss-estimation of the saturated hydraulic conductivity of soils may drastically impact the design of infiltration devices and the related extra-costs. Bagarello, B.; Castellini, M.; Di Prima,S.;Giordano ,G.; Iovino, M. (2013). Testing a simplified approach to determine field saturated soil hydraulic conductivity. Procedia Environmental Sciences 19 ( 2013 ) 599 - 608 Horton, R. (1933). The role of infiltration in the hydrologic cycle. American Geophysical Union Transactions 14, 446-460. Lassabatère, L.; Angulo-Jaramillo, R.; Soria, J.M.; Cuenca, R.; Braud, I.; Haverkamp, R.(2006). Beerkan estimation of soil transfer parameters through infiltration experiments - BEST. Soil Science Society of American Journal, Madison, v.70, p.521-532, 2006. Philip, J.R. (1957). The theory of Infiltration: 5. The Influence of the Initial Moisture Content. Soil Science, v.4, n.84, p.329-339, 1957. Wu, L.; Pan, L.; Mitchell, J.; Sanden, B. (1999). Measuring satured hydraulic conductivity using a generalized solution for single-ringle infiltrometers. Soil Sci.Soc.Am.J.63, 788-792

Sedimentological Control on Hydrate Saturation Distribution in Arctic Gas-Hydrate-Bearing Deposits

NASA Astrophysics Data System (ADS)

Behseresht, J.; Peng, Y.; Bryant, S. L.

2010-12-01

Grain size variations along with the relative rates of fluid phases migrating into the zone of hydrate stability, plays an important role in gas-hydrate distribution and its morphologic characteristics. In the Arctic, strata several meters thick containing large saturations of gas hydrate are often separated by layers containing small but nonzero hydrate saturations. Examples are Mt. Elbert, Alaska and Mallik, NW Territories. We argue that this sandwich type hydrate saturation distribution is consistent with having a gas phase saturation within the sediment when the base of gas hydrate stability zone (BGHSZ) was located above the sediment package. The volume change during hydrate formation process derives movement of fluid phases into the GHSZ. We show that this fluid movement -which is mainly governed by characteristic relative permeability curves of the host sediment-, plays a crucial role in the amount of hydrate saturation in the zone of major hydrate saturation. We develop a mechanistic model that enables estimating the final hydrate saturation from an initial gas/water saturation in sediment with known relative permeability curves. The initial gas/water saturation is predicted using variation of capillary entry pressure with depth, which in turn depends on the variation in grain-size distribution. This model provides a mechanistic approach for explaining large hydrate saturations (60%-75%) observed in zones of major hydrate saturation considering the governing characteristic relative permeability curves of the host sediments. We applied the model on data from Mount Elbert well on the Alaskan North Slope. It is shown that, assuming a cocurrent flow of gas and water into the GHSZ, such large hydrate saturations (up to 75%) cannot result from large initial gas saturations (close to 1-Sw,irr) due to limitations on water flux imposed by typical relative permeability curves. They could however result from modest initial gas saturations (ca. 40%) at which we have reasonable phase mobility ratios required for appropriate relative rates of gas and water transporting into GHSZ to form large hydrate saturations. Nevertheless, from the profile of capillary entry pressure vs. depth, we expect large initial gas saturations and thus the final high hydrate saturation suggests another form of water flow: water moves down through accumulated hydrate from the unfrozen water above. For this to happen the water phase must remain connected within the hydrate-bearing sediment. This seems plausible in hydrate bearing sediments because hydrate formation will be stopped before water saturation gets to very low values (lower than Sw,irr) due to salinity build up. The location of small hydrate saturations (10-15%) is consistent with the location of the residual gas phase established during water imbibition into these locations while they serve as a gas source to the layers above.

Free-jet acoustic investigation of high-radius-ratio coannular plug nozzles. Comprehensive data report, volume 1

NASA Technical Reports Server (NTRS)

Knott, P. R.; Janardan, B. A.; Majjigi, R. K.; Shutiani, P. K.; Vogt, P. G.

1981-01-01

Six coannular plug nozzle configurations having inverted velocity and temperature profiles, and a baseline convergent conical nozzle were tested for simulated flight acoustic evaluation in General Electric's Anechoic Free-Jet Acoustic Facility. The nozzles were tested over a range of test conditions that are typical of a Variable Cycle Engine for application to advanced high speed aircraft. The outer stream radius ratio for most of the configurations was 0.853, and the inner-stream-outer-stream area ratio was tested in the range of 0.54. Other variables investigated were the influence of bypass struts, a simple noncontoured convergent-divergent outer stream nozzle for forward quadrant shock noise control, and the effects of varying outer stream radius and inner-stream-to-outer-stream velocity ratios on the flight noise signatures of the nozzles. It was found that in simulated flight, the high-radius-ratio coannular plug nozzles maintain their jet noise and shock noise reduction features previously observed in static testing. The presence of nozzle bypass structs will not significantly effect the acoustic noise reduction features of a General Electric-type nozzle design. A unique coannular plug nozzle flight acoustic spectral prediction method was identified and found to predict the measured results quite well. Special laser velocimeter and acoustic measurements were performed which have given new insight into the jet and shock noise reduction mechanisms of coannular plug nozzles with regard to identifying further beneficial research efforts.

Multifocal microlens for bionic compound eye

NASA Astrophysics Data System (ADS)

Cao, Axiu; Wang, Jiazhou; Pang, Hui; Zhang, Man; Shi, Lifang; Deng, Qiling; Hu, Song

2017-10-01

Bionic compound eye optical element composed of multi-dimensional sub-eye microlenses plays an important role in miniaturizing the volume and weight of an imaging system. In this manuscript, we present a novel structure of the bionic compound eye with multiple focal lengths. By the division of the microlens into two concentric radial zones including the inner zone and the outer zone with independent radius, the sub-eye which is a multi-level micro-scale structure can be formed with multiple focal lengths. The imaging capability of the structure has been simulated. The results show that the optical information in different depths can be acquired by the structure. Meanwhile, the parameters including aperture and radius of the two zones, which have an influence on the imaging quality have been analyzed and discussed. With the increasing of the ratio of inner and outer aperture, the imaging quality of the inner zone is becoming better, and instead the outer zone will become worse. In addition, through controlling the radius of the inner and outer zone independently, the design of sub-eye with different focal lengths can be realized. With the difference between the radius of the inner and outer zone becoming larger, the imaging resolution of the sub-eye will decrease. Therefore, the optimization of the multifocal structure should be carried out according to the actual imaging quality demands. Meanwhile, this study can provide references for the further applications of multifocal microlens in bionic compound eye.

Spreading dynamics of superposed liquid drops on a spinning disk

NASA Astrophysics Data System (ADS)

Sahoo, Subhadarshinee; Orpe, Ashish V.; Doshi, Pankaj

2018-01-01

We have experimentally studied simultaneous spreading of superposed drops of two Newtonian liquids on top of a horizontal spinning disk using the flow visualization technique. An inner drop of high surface tension liquid is placed centrally on the disk followed by a drop of outer liquid (lower surface tension) placed exactly above that. The disk is then rotated at a desired speed for a range of volume ratios of two liquids. Such an arrangement of two superposed liquid drops does not affect the spreading behavior of the outer liquid but influences that of the inner liquid significantly. The drop spreads to a larger extent and breaks into more fingers (Nf) as compared to the case where the same liquid is spreading in the absence of outer liquid. The experimentally observed number of fingers is compared with the prediction using available theory for single liquid. It is found that the theory over-predicts the value of Nf for the inner liquid while it is covered by an outer liquid. We provide a theoretical justification for this observation using linear stability analysis. Our analysis demonstrates that for small but finite surface tension ratio of the two liquids, the presence of the outer interface reduces the value of the most unstable wave number which is equivalent to the decrease in the number of fingers observed experimentally. Finally, sustained rotation of the disk leads to the formation of droplets at the tip of the fingers traveling outwards.

Free-jet acoustic investigation of high-radius-ratio coannular plug nozzles. Comprehensive data report, volume 2

NASA Technical Reports Server (NTRS)

Vogt, P. G.; Bhutiani, P. K.; Knott, P. R.

1981-01-01

Laser velocimeter data, collected as part of an acoustic investigation of coannular plug nozzles, is provided. The type of traverse, position, and histogram number is given along with the mean and turbulent velocity data. The velocites are normalized with respect to the outer flow velocity and the 'mixed' velocity.

Biological Survey, Buffalo River and Outer Harbor of Buffalo, New York. Volume II. Data Report.

DTIC Science & Technology

1982-06-01

SamplintDate: 4-23-81 and 4-24-81 MG - male, gravid FG - female, gravid S - spent Secies Iength(cm) Sex Condition Station 14 Net lost due to log jam moving down...virginiana Duchesne. Strawberry Melilotus officinklis (L.) Dear. Sweet yellow clover annuus (L.) Pers. Fleabane Rosa sp. Rose Rhamnus sp. Buckthorn

Effects of initial saturation on properties modification and displacement of tetrachloroethene with aqueous isobutanol.

PubMed

Boyd, Glen R; Ocampo-Gómez, Ana M; Li, Minghua; Husserl, Johana

2006-11-20

Packed column experiments were conducted to study effects of initial saturation of tetrachloroethene (PCE) in the range of 1.0-14% pore volume (PV) on mobilization and downward migration of the non-aqueous phase liquid (NAPL) product upon contact with aqueous isobutanol ( approximately 10 vol.%). This study focused on the consequences of swelling beyond residual saturation. Columns were packed with mixtures of neat PCE, water and glass beads and waterflooded to establish a desired homogeneous residual saturation, and then flooded with aqueous isobutanol under controlled hydraulic conditions. Results showed a critical saturation of approximately 8% PV for these packed column experimental conditions. At low initial PCE saturations (<8% PV), experimental results showed reduced risk of NAPL-product migration upon contact with aqueous isobutanol. At higher initial PCE saturations (>8% PV), results showed NAPL-product mobilization and downward migration which was attributed to interfacial tension (IFT) reduction, swelling of the NAPL-product, and reduced density modification. Packed column results were compared with good agreement to theoretical predictions of NAPL-product mobilization using the total trapping number, N(T). In addition to the packed column study, preliminary batch experiments were conducted to study the effects of PCE volumetric fraction in the range of 0.5-20% on density, viscosity, and IFT modification as a function of time following contact with aqueous isobutanol ( approximately 10 vol.%). Modified NAPL-product fluid properties approached equilibrium within approximately 2 h of contact for density and viscosity. IFT reduction occurred immediately as expected. Measured fluid properties were compared with good agreement to theoretical equilibrium predictions based on UNIQUAC. Overall, this study demonstrates the importance of initial DNAPL saturation, and the associated risk of downward NAPL-product migration, in applying alcohol flooding for remediation of DNAPL contaminated ground water sites.

Using noble gas tracers to estimate residual CO2 saturation in the field: results from the CO2CRC Otway residual saturation and dissolution test

NASA Astrophysics Data System (ADS)

LaForce, T.; Ennis-King, J.; Paterson, L.

2013-12-01

Residual CO2 saturation is a critically important parameter in CO2 storage as it can have a large impact on the available secure storage volume and post-injection CO2 migration. A suite of single-well tests to measure residual trapping was conducted at the Otway test site in Victoria, Australia during 2011. One or more of these tests could be conducted at a prospective CO2 storage site before large-scale injection. The test involved injection of 150 tonnes of pure carbon dioxide followed by 454 tonnes of CO2-saturated formation water to drive the carbon dioxide to residual saturation. This work presents a brief overview of the full test sequence, followed by the analysis and interpretation of the tests using noble gas tracers. Prior to CO2 injection krypton (Kr) and xenon (Xe) tracers were injected and back-produced to characterise the aquifer under single-phase conditions. After CO2 had been driven to residual the two tracers were injected and produced again. The noble gases act as non-partitioning aqueous-phase tracers in the undisturbed aquifer and as partitioning tracers in the presence of residual CO2. To estimate residual saturation from the tracer test data a one-dimensional radial model of the near-well region is used. In the model there are only two independent parameters: the apparent dispersivity of each tracer and the residual CO2 saturation. Independent analysis of the Kr and Xe tracer production curves gives the same estimate of residual saturation to within the accuracy of the method. Furthermore the residual from the noble gas tracer tests is consistent with other measurements in the sequence of tests.

Probabilistic inversion of electrical resistivity data from bench-scale experiments: On model parameterization for CO2 sequestration monitoring

NASA Astrophysics Data System (ADS)

Breen, S. J.; Lochbuehler, T.; Detwiler, R. L.; Linde, N.

2013-12-01

Electrical resistivity tomography (ERT) is a well-established method for geophysical characterization and has shown potential for monitoring geologic CO2 sequestration, due to its sensitivity to electrical resistivity contrasts generated by liquid/gas saturation variability. In contrast to deterministic ERT inversion approaches, probabilistic inversion provides not only a single saturation model but a full posterior probability density function for each model parameter. Furthermore, the uncertainty inherent in the underlying petrophysics (e.g., Archie's Law) can be incorporated in a straightforward manner. In this study, the data are from bench-scale ERT experiments conducted during gas injection into a quasi-2D (1 cm thick), translucent, brine-saturated sand chamber with a packing that mimics a simple anticlinal geological reservoir. We estimate saturation fields by Markov chain Monte Carlo sampling with the MT-DREAM(ZS) algorithm and compare them quantitatively to independent saturation measurements from a light transmission technique, as well as results from deterministic inversions. Different model parameterizations are evaluated in terms of the recovered saturation fields and petrophysical parameters. The saturation field is parameterized (1) in cartesian coordinates, (2) by means of its discrete cosine transform coefficients, and (3) by fixed saturation values and gradients in structural elements defined by a gaussian bell of arbitrary shape and location. Synthetic tests reveal that a priori knowledge about the expected geologic structures (as in parameterization (3)) markedly improves the parameter estimates. The number of degrees of freedom thus strongly affects the inversion results. In an additional step, we explore the effects of assuming that the total volume of injected gas is known a priori and that no gas has migrated away from the monitored region.

Reflectance-difference spectroscopy of GaAs crystal growth by OMCVD

NASA Astrophysics Data System (ADS)

Colas, Etienne G.; Aspnes, David E.; Bhat, Rajaram J.; Studna, A. A.; Koza, M. A.; Keramidas, Vassilis G.

1990-02-01

This paper summarizes results of our investigations of growth on (001) and (110) GaAs by atmospheric-pressure organometallic chemical vapor deposition (OMCVD). We follow evolutions of surface species to a sensitivity of 0.01 monolayer (ML) on a time scale of 0.1 s under alternating flows of trimethylgallium (TMG) and arsine (AsH3) as functions of partial pressure, sample temperature, and surface orienta-tion. The reaction of TMG with an AsH3-saturated (001) surface is rate-limited by com-petition between desorption and decomposition of TMG molecules chemisorbed to surface lattice sites via an excluded-volume mechanism, while the reaction of AsH3 with the TMG-saturated (001) surface is essentially instantaneous. In contrast, TMG reacts essentially instantaneously with the AsH3 -saturated (110) surface while the AsH3 reaction with the TMG-saturated (110) surface is the rate-limiting step. However, the latter rate is not intrinsic to the AsH3-surface reaction but appears to be determined by desorption of adsorbed species that block active sites.

Platinum-bearing chromite layers are caused by pressure reduction during magma ascent.

PubMed

Latypov, Rais; Costin, Gelu; Chistyakova, Sofya; Hunt, Emma J; Mukherjee, Ria; Naldrett, Tony

2018-01-31

Platinum-bearing chromitites in mafic-ultramafic intrusions such as the Bushveld Complex are key repositories of strategically important metals for human society. Basaltic melts saturated in chromite alone are crucial to their generation, but the origin of such melts is controversial. One concept holds that they are produced by processes operating within the magma chamber, whereas another argues that melts entering the chamber were already saturated in chromite. Here we address the problem by examining the pressure-related changes in the topology of a Mg 2 SiO 4 -CaAl 2 Si 2 O 8 -SiO 2 -MgCr 2 O 4 quaternary system and by thermodynamic modelling of crystallisation sequences of basaltic melts at 1-10 kbar pressures. We show that basaltic melts located adjacent to a so-called chromite topological trough in deep-seated reservoirs become saturated in chromite alone upon their ascent towards the Earth's surface and subsequent cooling in shallow-level chambers. Large volumes of these chromite-only-saturated melts replenishing these chambers are responsible for monomineralic layers of massive chromitites with associated platinum-group elements.

A Modified Benedict-Webb-Rubin Equation of State for the Thermodynamic Properties of R152a (1,1-difluoroethane)

NASA Astrophysics Data System (ADS)

Outcalt, Stephanie L.; McLinden, Mark O.

1996-03-01

A modified Benedict-Webb-Rubin (MBWR) equation of state has been developed for R152a (1,1-difluoroethane). The correlation is based on a selection of available experimental thermodynamic property data. Single-phase pressure-volume-temperature (PVT), heat capacity, and sound speed data, as well as second virial coefficient, vapor pressure, and saturated liquid and saturated vapor density data, were used with multi-property linear least-squares fitting to determine the 32 adjustable coefficients of the MBWR equation. Ancillary equations representing the vapor pressure, saturated liquid and saturated vapor densities, and the ideal gas heat capacity were determined. Coefficients for the equation of state and the ancillary equations are given. Experimental data used in this work covered temperatures from 162 K to 453 K and pressures to 35 MPa. The MBWR equation established in this work may be used to predict thermodynamic properties of R152a from the triple-point temperature of 154.56 K to 500 K and for pressures up to 60 MPa except in the immediate vicinity of the critical point.

Dynamics of deformation and pinch-off of a migrating compound droplet in a tube

NASA Astrophysics Data System (ADS)

Borthakur, Manash Pratim; Biswas, Gautam; Bandyopadhyay, Dipankar

2018-04-01

A computational fluid dynamic investigation has been carried out to study the dynamics of a moving compound droplet inside a tube. The motions associated with such a droplet is uncovered by solving the axisymmetric Navier-Stokes equations in which the spatiotemporal evolution of a pair of twin-deformable interfaces has been tracked employing the volume-of-fluid approach. The deformations at the interfaces and their subsequent dynamics are found to be stimulated by the subtle interplay between the capillary and viscous forces. The simulations uncover that when a compound drop composed of concentric inner and outer interfaces migrates inside a tube, initially in the unsteady domain of evolution, the inner drop shifts away from the concentric position to reach a morphology of constant eccentricity at the steady state. The coupled motions of the droplets in the unsteady regime causes a continuous deformation of the inner and outer interfaces to obtain a configuration with a (an) prolate (oblate) shaped outer (inner) interface. The magnitudes of capillary number and viscosity ratio are found to have significant influence on the temporal evolution of the interfacial deformations as well as the eccentricity of the droplets. Further, the simulations uncover that, following the asymmetric deformation of the interfaces, the migrating compound droplet can undergo an uncommon breakup stimulated by a rather irregular pinch-off of the outer shell. The breakup is found to initiate with the thinning of the outer shell followed by the pinch-off. Interestingly, the kinetics of the thinning of outer shell is found to follow two distinct power-law regimes—a swiftly thinning stage at the onset followed by a rate limiting stage before pinch-off, which eventually leads to the uncommon breakup of the migrating compound droplets.

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 the pressure gradient. The arrival time of P-wave became retarded and its amplitude became smaller as the degree of CO2 saturation increases. However no change was observed in S-wave in both characters. According to our results, time-lapse measurements of P-wave signals can be a monitoring tool of the subsurface migration of CO2, thus of detecting even its leakage.

nZVI injection into variably saturated soils: Field and modeling study.

PubMed

Chowdhury, Ahmed I A; Krol, Magdalena M; Kocur, Christopher M; Boparai, Hardiljeet K; Weber, Kela P; Sleep, Brent E; O'Carroll, Denis M

2015-12-01

Nano-scale zero valent iron (nZVI) has been used at a number of contaminated sites over the last decade. At most of these sites, significant decreases in contaminant concentrations have resulted from the application of nZVI. However, limited work has been completed investigating nZVI field-scale mobility. In this study, a field test was combined with numerical modeling to examine nZVI reactivity along with transport properties in variably saturated soils. The field test consisted of 142L of carboxymethyle cellulose (CMC) stabilized monometallic nZVI synthesized onsite and injected into a variably saturated zone. Periodic groundwater samples were collected from the injection well, as well as, from two monitoring wells to analyze for chlorinated solvents and other geochemistry indicators. This study showed that CMC stabilized monometallic nZVI was able to decrease tricholorethene (TCE) concentrations in groundwater by more than 99% from the historical TCE concentrations. A three dimensional, three phase, finite difference numerical simulator, (CompSim) was used to further investigate nZVI and polymer transport at the variably saturated site. The model was able to accurately predict the field observed head data without parameter fitting. In addition, the numerical simulator estimated the mass of nZVI delivered to the saturated and unsaturated zones and distinguished the nZVI phase (i.e. aqueous or attached). The simulation results showed that the injected slurry migrated radially outward from the injection well, and therefore nZVI transport was governed by injection velocity and viscosity of the injected solution. A suite of sensitivity analyses was performed to investigate the impact of different injection scenarios (e.g. different volume and injection rate) on nZVI migration. Simulation results showed that injection of a higher nZVI volume delivered more iron particles at a given distance; however, the travel distance was not proportional to the increase in volume. Moreover, simulation results showed that using a 1D transport equation to simulate nZVI migration in the subsurface may overestimate the travel distance. This is because the 1D transport equation assumes a constant velocity while pore water velocity radially decreases from the well during injection. This study suggests that on-site synthesized nZVI particles are mobile in the subsurface and that a numerical simulator can be a valuable tool for optimal design of nZVI field applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Estimation of infiltration and hydraulic resistance in furrow irrigation, with infiltration dependent on flow depth

USDA-ARS?s Scientific Manuscript database

The estimation of parameters of a flow-depth dependent furrow infiltration model and of hydraulic resistance, using irrigation evaluation data, was investigated. The estimated infiltration parameters are the saturated hydraulic conductivity and the macropore volume per unit area. Infiltration throu...

Surface current patterns suggested by suspended sediment distribution over the outer continental margin, Bering Sea

USGS Publications Warehouse

Karl, Herman A.; Carlson, P.R.

1987-01-01

Samples of total suspended matter (TSM) were collected at the surface over the northern outer continental margin of the Bering Sea during the summers of 1980 and 1981. Volume concentrations of surface TSM averaged 0.6 and 1.1 mg l-1 for 1980 and 1981, respectively. Organic matter, largely plankton, made up about 65% of the near-surface TSM for both years. Distributions of TSM suggested that shelf circulation patterns were characterized either by meso- and large- scale eddies or by cross-shelf components of flow superimposed on a general northwesterly net drift. These patterns may be caused by large submarine canyons which dominate the physiography of this part of the Bering Sea continental margin. ?? 1987.

Liquid balance monitoring inside conventional, Retrofit, and bio-reactor landfill cells

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

Abichou, Tarek, E-mail: abichou@eng.fsu.edu; Barlaz, Morton A.; Green, Roger

Highlights: • The Retrofit, Control, and As-Built cells received 48, 14, and 213 L Mg{sup −1} (liters of liquids per metric ton of waste). • The leachate collection system yielded 60, 57 and 198 L Mg{sup −1} from the Retrofit, Control, and As-Built cells. • The head on liner in all cells was below regulatory limits. • Measured moisture content of the waste samples was consistent with that calculated from accumulated liquid by balance. • The in-place saturated hydraulic conductivity of the MSW was calculated to be in the range of 10{sup −8} to 10{sup −7} m s{sup −1}. -more » Abstract: The Outer Loop landfill bioreactor (OLLB) in Louisville, KY, USA has been the site of a study to evaluate long-term bioreactor performance at a full-scale operational landfill. Three types of landfill units were studied including a conventional landfill (Control cell), a new landfill area that had an air addition and recirculation piping network installed as waste was being placed (As-Built cell), and a conventional landfill that was modified to allow for liquids recirculation (Retrofit cell). During the monitoring period, the Retrofit, Control, and As-Built cells received 48, 14, and 213 L Mg{sup −1} (liters of liquids per metric ton of waste), respectively. The leachate collection system yielded 60, 57 and 198 L Mg{sup −1} from the Retrofit, Control, and As-Built cells, respectively. The head on liner in all cells was below regulatory limits. In the Control and As-Built cells, leachate head on liner decreased once waste placement stopped. The measured moisture content of the waste samples was consistent with that calculated from the estimate of accumulated liquid by the liquid balance. Additionally, measurements on excavated solid waste samples revealed large spatial variability in waste moisture content. The degree of saturation in the Control cells decreased from 85% to 75%. The degree of saturation increased from 82% to 83% due to liquids addition in the Retrofit cells and decreased back to 80% once liquid addition stopped. In the As-Built cells, the degree of saturation increased from 87% to 97% during filling activities and then started to decrease soon after filling activities stopped to reach 92% at the end of the monitoring period. The measured leachate generation rates were used to estimate an in-place saturated hydraulic conductivity of the MSW in the range of 10{sup −8} to 10{sup −7} m s{sup −1} which is lower than previous reports. In the Control and Retrofit cells, the net loss in liquids, 43 and 12 L Mg{sup −1}, respectively, was similar to the measured settlement of 15% and 5–8% strain, respectively (Abichou et al., 2013). The increase in net liquid volume in the As-Built cells indicates that the 37% (average) measured settlement strain in these cells cannot be due to consolidation as the waste mass did not lose any moisture but rather suggests that settlement was attributable to lubrication of waste particle contacts, softening of flexible porous materials, and additional biological degradation.« less

Methane hydrate formation in partially water-saturated Ottawa sand

USGS Publications Warehouse

Waite, W.F.; Winters, W.J.; Mason, D.H.

2004-01-01

Bulk properties of gas hydrate-bearing sediment strongly depend on whether hydrate forms primarily in the pore fluid, becomes a load-bearing member of the sediment matrix, or cements sediment grains. Our compressional wave speed measurements through partially water-saturated, methane hydrate-bearing Ottawa sands suggest hydrate surrounds and cements sediment grains. The three Ottawa sand packs tested in the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) contain 38(1)% porosity, initially with distilled water saturating 58, 31, and 16% of that pore space, respectively. From the volume of methane gas produced during hydrate dissociation, we calculated the hydrate concentration in the pore space to be 70, 37, and 20% respectively. Based on these hydrate concentrations and our measured compressional wave speeds, we used a rock physics model to differentiate between potential pore-space hydrate distributions. Model results suggest methane hydrate cements unconsolidated sediment when forming in systems containing an abundant gas phase.

Numerical simulation of superheated vapor bubble rising in stagnant liquid

NASA Astrophysics Data System (ADS)

Samkhaniani, N.; Ansari, M. R.

2017-09-01

In present study, the rising of superheated vapor bubble in saturated liquid is simulated using volume of fluid method in OpenFOAM cfd package. The surface tension between vapor-liquid phases is considered using continuous surface force method. In order to reduce spurious current near interface, Lafaurie smoothing filter is applied to improve curvature calculation. Phase change is considered using Tanasawa mass transfer model. The variation of saturation temperature in vapor bubble with local pressure is considered with simplified Clausius-Clapeyron relation. The couple velocity-pressure equation is solved using PISO algorithm. The numerical model is validated with: (1) isothermal bubble rising and (2) one-dimensional horizontal film condensation. Then, the shape and life time history of single superheated vapor bubble are investigated. The present numerical study shows vapor bubble in saturated liquid undergoes boiling and condensation. It indicates bubble life time is nearly linear proportional with bubble size and superheat temperature.

Tastier and healthier alternatives to French fries.

PubMed

Rommens, Caius M; Shakya, Roshani; Heap, Mark; Fessenden, Kristi

2010-05-01

The effect of both the origin and shape of potato cuts on fry quality was investigated in this study. Linear strips from the inner core of tubers were compared to those from outer tissues, both before and after processing, and strips from either specific tissues or whole peeled tubers were also evaluated against ring-shaped cuts. Both strips and rings had 0.7 cm sides and, in most cases, a volume of 4.9 cm(3). They were analyzed for moisture content, antioxidants, asparagine, and reducing sugars. The material was then blanched, dipped in 0.5% disodium acid pyrophosphate and 0.3% glucose, dried at 77 degrees C, par-fried in soybean oil at 191 degrees C, and finish-fried at 168 degrees C. The fried product was analyzed for sensory characteristics and oil, salt, and acrylamide content. Our results showed that strips from the inner core absorbed 28% more oil and exhibited inferior sensory characteristics compared to strips from the outer parts. The extended drying and frying times needed to match the crispness and flavor of inner strips to those of regularly fried outer strips resulted in a further increased absorption of oil and, importantly, triggered a 163% increase in levels of the toxic Maillard reaction product acrylamide. Potato rings consisted of higher dry matter material, contained more antioxidants, and had a lower surface-to-volume ratio than the conventional linear strips. Upon processing, they also absorbed 22% less oil, contained 26% less salt, and displayed superior sensory properties. Thus, ring fries may represent an attractive alternative to French fries as processed staple food.

Effects of imidazolium-based ionic surfactants on the size and dynamics of phosphatidylcholine bilayers with saturated and unsaturated chains.

PubMed

Lee, Hwankyu

2015-07-01

Imidazolium-based ionic surfactants of different sizes were simulated with 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers. Regardless of the phospholipid type, larger surfactants at higher concentrations more significantly insert into the bilayer and increase the bilayer-surface size, in agreement with experiments and previous simulations. Insertion of surfactants only slightly decreases the bilayer thickness, as also observed in experiments. Although the surfactant insertion and its effect on the bilayer size and thickness are similar in different types of bilayers, the volume fractions of surfactants in the bilayer are higher for DMPC bilayers than for POPC and DOPC bilayers. In particular, ionic surfactants with four hydrocarbons yield their volume fractions of 4.6% and 8.7%, respectively, in POPC and DMPC bilayers, in quantitative agreement with experimental values of ∼5% and ∼10%. Also, the inserted surfactants increase the lateral diffusivity of the bilayer, which depends on the bilayer type. These findings indicate that although the surfactant insertion does not depend on the bilayer type, the effects of surfactants on the volume fraction and bilayer dynamics occur more significantly in the DMPC bilayer because of the smaller area per lipid and shorter saturated tails, which helps explain the experimental observations regarding different volume fractions of surfactants in POPC and DMPC bilayers. Copyright © 2015 Elsevier Inc. All rights reserved.

Prognostic value of cardiovascular magnetic resonance imaging measurements corrected for age and sex in idiopathic pulmonary arterial hypertension.

PubMed

Swift, Andrew J; Rajaram, Smitha; Campbell, Michael J; Hurdman, Judith; Thomas, Steve; Capener, Dave; Elliot, Charlie; Condliffe, Robin; Wild, Jim M; Kiely, David G

2014-01-01

There are limited data on the prognostic value of cardiovascular magnetic resonance measurements in idiopathic pulmonary arterial hypertension, with no studies investigating the impact of correction of cardiovascular magnetic resonance indices for age and sex on prognostic value. Consecutive patients with idiopathic pulmonary arterial hypertension underwent cardiovascular magnetic resonance imaging at 1.5T. Steady-state free precession cardiac volumes and mass measurements were corrected for age, sex, and body surface area according to reference data and prognostic significance assessed. A total of 80 patients with idiopathic pulmonary arterial hypertension were identified, and 23 patients died during the mean follow-up of 32±14 months. Corrected for age, sex, and body surface area, right ventricular end-systolic volume (P=0.004) strongly predicted mortality, independent of World Health Organization functional class, mean right atrial pressure, cardiac index, and mixed venous oxygen saturations. Consideration should be given to correcting cardiovascular magnetic resonance measures for age, sex, and body surface area, particularly given the changing demographics of patients with idiopathic pulmonary arterial hypertension. Corrected right ventricular end-systolic volume is a strong prognostic marker in idiopathic pulmonary arterial hypertension, independent of invasively derived measurements, mean right atrial pressure cardiac index, and mixed venous oxygen saturations.

Hydrogen Fluoride and Fluorine Dispersion Models Integration Into the Air Force Dispersion Assessment Model. Volume 1

DTIC Science & Technology

1990-12-07

Sat (T) - apparent molecular weight of the saturated Vap vapor (kg/kmole) T saturation temperature (K) These apparent molecular weights of the vapor...any) are collected for 66m, 88.3s or 1O0s on filter paper. The aspiration rate is given to be 3.5 liters per minute. Since no real time measurament of...190.0 0.0000012+ 00 0.OOOOOE + 00 102 8 2 0 VAP THERMAL COND (XKV) PARAMETERS W/m K REF: 3.85700E-03 5 .27600E-05 2.261 00E-08 0.OOOOOE + 00 1 000.0

Experimental and numerical investigation of DNAPL infiltration and spreading in a 2-D sandbox by means of light transmission method

NASA Astrophysics Data System (ADS)

Zheng, F.; Shi, X.; Wu, J.; Gao, Y. W.

2013-12-01

Chlorinated solvents such as trichloroethene (TCE) and tetrachloroethene (PCE) are widespread groundwater contaminants often referred to as dense non-aqueous phase liquids (DNAPLs). Accuracy description of the spreading behavior and configuration for subsurface DNAPL migration is important, especially favourable for design effective remediation strategies. In this study, a 2-D experiment was conducted to investigate the infiltration behavior and spatial distribution of PCE in saturated porous media. Accusand 20/30 mesh sand (Unimin, Le Sueur, MN) was used as the background medium with two 70/80 and 60/70 mesh lenses embedded to simulate heterogeneous conditions. Dyed PCE of 100 ml was released into the flow cell at a constant rate of 2ml/min using a Harvard Apparatus syringe pump with a 50 ml glass syringe for two times, and 5 ml/min water was continuously injected through the inlet at the left side of the sandbox, while kept the same effluent rate at right side to create hydrodynamic condition. A light transmission (LT) system was used to record the migration of PCE and determine the saturation distribution of PCE in the sandbox experiment with a thermoelectrically air-cooled charged-coupled device (CCD) camera. All images were processed using MATLAB to calculate thickness-averaged PCE saturation for each pixel. Mass balance was checked through comparing injected known mounts of PCE with that calculated from LT analysis. Results showed that LT method is effective to delineate PCE migration pathways and quantify the saturation distribution. The relative errors of total PCE volumes calculated by LT analysis at different times were within 15% of the injected PCE volumes. The simulation are conducted using the multiphase modeling software T2VOC, which calibrated by the LT analysis results of three recorded time steps to fit with the complete spatial-temporal distribution of the PCE saturation. Model verification was then performed using the other eight recorded time steps. Simulated results showed that the model could successfully reproduce the migration pathways and distribution configuration observed from the laboratory experiment and LT analysis, excepted for a smaller pool height on the lenses, and a lower saturation values in PCE accumulation area due to local heterogeneities. Due to the influence of water flow, the PCE distribution was asymmetrical, and the PCE distribution area, pool height as well as PCE saturation in the accumulation region at right side was much greater. Acknowledge: This work is financially supported by the National Nature Science Foundation of China grants No. 41030746 and 41172206.

Relations between macropore network characteristics and the degree of preferential solute transport

NASA Astrophysics Data System (ADS)

Larsbo, M.; Koestel, J.; Jarvis, N.

2014-12-01

The characteristics of the soil macropore network determine the potential for fast transport of agrochemicals and contaminants through the soil. The objective of this study was to examine the relationships between macropore network characteristics, hydraulic properties and state variables and measures of preferential transport. Experiments were carried out under near-saturated conditions on undisturbed columns sampled from four agricultural topsoils of contrasting texture and structure. Macropore network characteristics were computed from 3-D X-ray tomography images of the soil pore system. Non-reactive solute transport experiments were carried out at five steady-state water flow rates from 2 to 12 mm h-1. The degree of preferential transport was evaluated by the normalised 5% solute arrival time and the apparent dispersivity calculated from the resulting breakthrough curves. Near-saturated hydraulic conductivities were measured on the same samples using a tension disc infiltrometer placed on top of the columns. Results showed that many of the macropore network characteristics were inter-correlated. For example, large macroporosities were associated with larger specific macropore surface areas and better local connectivity of the macropore network. Generally, an increased flow rate resulted in earlier solute breakthrough and a shifting of the arrival of peak concentration towards smaller drained volumes. Columns with smaller macroporosities, poorer local connectivity of the macropore network and smaller near-saturated hydraulic conductivities exhibited a greater degree of preferential transport. This can be explained by the fact that, with only two exceptions, global (i.e. sample scale) continuity of the macropore network was still preserved at low macroporosities. Thus, for any given flow rate, pores of larger diameter were actively conducting solute in soils of smaller near-saturated hydraulic conductivity. This was associated with larger local transport velocities and, hence, less time for equilibration between the macropores and the surrounding matrix which made the transport more preferential. Conversely, the large specific macropore surface area and well-connected macropore networks associated with columns with large macroporosities limit the degree of preferential transport because they increase the diffusive flux between macropores and the soil matrix and they increase the near-saturated hydraulic conductivity. The normalised 5% arrival times were most strongly correlated with the estimated hydraulic state variables (e.g. with the degree of saturation in the macropores R2 = 0.589), since these combine into one measure the effects of irrigation rate and the near-saturated hydraulic conductivity function, which in turn implicitly depends on the volume, size distribution, global continuity, local connectivity and tortuosity of the macropore network.

The coordination of ploidy and cell size differs between cell layers in leaves

PubMed Central

Katagiri, Yohei; Hasegawa, Junko; Fujikura, Ushio; Hoshino, Rina; Matsunaga, Sachihiro; Tsukaya, Hirokazu

2016-01-01

Growth and developmental processes are occasionally accompanied by multiple rounds of DNA replication, known as endoreduplication. Coordination between endoreduplication and cell size regulation often plays a crucial role in proper organogenesis and cell differentiation. Here, we report that the level of correlation between ploidy and cell volume is different in the outer and inner cell layers of leaves of Arabidopsis thaliana using a novel imaging technique. Although there is a well-known, strong correlation between ploidy and cell volume in pavement cells of the epidermis, this correlation was extremely weak in palisade mesophyll cells. Induction of epidermis cell identity based on the expression of the homeobox gene ATML1 in mesophyll cells enhanced the level of correlation between ploidy and cell volume to near that of wild-type epidermal cells. We therefore propose that the correlation between ploidy and cell volume is regulated by cell identity. PMID:26903507

Sparse aperture endoscope

DOEpatents

Fitch, J.P.

1999-07-06

An endoscope is disclosed which reduces the volume needed by the imaging part, maintains resolution of a wide diameter optical system, while increasing tool access, and allows stereographic or interferometric processing for depth and perspective information/visualization. Because the endoscope decreases the volume consumed by imaging optics such allows a larger fraction of the volume to be used for non-imaging tools, which allows smaller incisions in surgical and diagnostic medical applications thus produces less trauma to the patient or allows access to smaller volumes than is possible with larger instruments. The endoscope utilizes fiber optic light pipes in an outer layer for illumination, a multi-pupil imaging system in an inner annulus, and an access channel for other tools in the center. The endoscope is amenable to implementation as a flexible scope, and thus increases it's utility. Because the endoscope uses a multi-aperture pupil, it can also be utilized as an optical array, allowing stereographic and interferometric processing. 7 figs.

Sparse aperture endoscope

DOEpatents

Fitch, Joseph P.

1999-07-06

An endoscope which reduces the volume needed by the imaging part thereof, maintains resolution of a wide diameter optical system, while increasing tool access, and allows stereographic or interferometric processing for depth and perspective information/visualization. Because the endoscope decreases the volume consumed by imaging optics such allows a larger fraction of the volume to be used for non-imaging tools, which allows smaller incisions in surgical and diagnostic medical applications thus produces less trauma to the patient or allows access to smaller volumes than is possible with larger instruments. The endoscope utilizes fiber optic light pipes in an outer layer for illumination, a multi-pupil imaging system in an inner annulus, and an access channel for other tools in the center. The endoscope is amenable to implementation as a flexible scope, and thus increases the utility thereof. Because the endoscope uses a multi-aperture pupil, it can also be utilized as an optical array, allowing stereographic and interferometric processing.

Influence of microgravity on cellular differentiation in root caps of Zea mays

NASA Technical Reports Server (NTRS)

Moore, R.; Fondren, W. M.; McClelen, C. E.; Wang, C. L.

1987-01-01

We launched imbibed seeds of Zea mays into outer space aboard the space shuttle Columbia to determine the influence of microgravity on cellular differentiation in root caps. The influence of microgravity varied with different stages of cellular differentiation. Overall, microgravity tended to 1) increase relative volumes of hyaloplasm and lipid bodies, 2) decrease the relative volumes of plastids, mitochondria, dictyosomes, and the vacuome, and 3) exert no influence on the relative volume of nuclei in cells comprising the root cap. The reduced allocation of dictyosomal volume in peripheral cells of flight-grown seedlings correlated positively with their secretion of significantly less mucilage than peripheral cells of Earth-grown seedlings. These results indicate that 1) microgravity alters the patterns of cellular differentiation and structures of all cell types comprising the root cap, and 2) the influence of microgravity on cellular differentiation in root caps of Zea mays is organelle specific.

Deep-convection events foster carbonate ion reduction in deep coral reefs

NASA Astrophysics Data System (ADS)

Perez, Fiz F.; Fontela, Marcos; Garcia-Ibañez, Maribel I.; Lherminier, Pascale; Zunino, Patricia; de la Paz, Mercedes; Padín, Xose A.; Alonso-Pérez, Fernando; Velo, Anton; Guallart, Elisa F.; Mercier, Herle

2017-04-01

Since millennial times, water mass circulation and deep-convection events have been transforming warm upper waters at high latitudes into cold and well-oxygenated deep waters. These processes have filled the deep North Atlantic Ocean with waters moderately saturated in calcium carbonate, thus promoting the growth of stony corals, which are hotspots of biodiversity. During the Anthropocene, the meridional circulation has been conveying cumulative amounts of more acidified waters with lower calcium carbonate saturation levels due to the incorporation of anthropogenic carbon dioxide, with very harsh conditions for deep cold-water corals projected by 2100. We evaluate the diminution of calcium carbonate saturation levels (aragonite form) due to the increase in anthropogenic carbon dioxide during the last two decades (2002-2016). We observe a strong decrease in the aragonite saturation levels concomitant with the reduction in the volume transport of aragonite-saturated waters. We estimate a 30-35% reduction in the transport of ion carbonate excess over the saturation levels with respect to the natural carbon cycle for the period 2002-2016. This reduction is associated with an increase in the downward transport of hydrogen ions. We also observe a heaving of the aragonite saturation horizons during the last 25 years, which is estimated at 6 m year-1 for the deep waters and 12-14 m year-1 for the intermediated waters. The harsh winters of 2015 and 2016 have fostered the fast addition of more acidified water into the lower layers of the North Atlantic through deep-convection events. In the future scenario of 2oC warming, the anthropogenic carbon dioxide in the water column would be double than today and the associated transport of hydrogen ions towards the bottom water would reduce the aragonite saturation levels to 60-80% with respect to preindustrial levels. This reduction in the aragonite saturation levels would suppose a strong diminution of the North Atlantic habitats where stony corals will be able to inhabit.

Comparison of up-scaling methods in poroelasticity and its generalizations

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

Berryman, J G

2003-12-13

Four methods of up-scaling coupled equations at the microscale to equations valid at the mesoscale and/or macroscale for fluid-saturated and partially saturated porous media will be discussed, compared, and contrasted. The four methods are: (1) effective medium theory, (2) mixture theory, (3) two-scale and multiscale homogenization, and (4) volume averaging. All these methods have advantages for some applications and disadvantages for others. For example, effective medium theory, mixture theory, and homogenization methods can all give formulas for coefficients in the up-scaled equations, whereas volume averaging methods give the form of the up-scaled equations but generally must be supplemented with physicalmore » arguments and/or data in order to determine the coefficients. Homogenization theory requires a great deal of mathematical insight from the user in order to choose appropriate scalings for use in the resulting power-law expansions, while volume averaging requires more physical insight to motivate the steps needed to find coefficients. Homogenization often is performed on periodic models, while volume averaging does not require any assumption of periodicity and can therefore be related very directly to laboratory and/or field measurements. Validity of the homogenization process is often limited to specific ranges of frequency - in order to justify the scaling hypotheses that must be made - and therefore cannot be used easily over wide ranges of frequency. However, volume averaging methods can quite easily be used for wide band data analysis. So, we learn from these comparisons that a researcher in the theory of poroelasticity and its generalizations needs to be conversant with two or more of these methods to solve problems generally.« less

Formation evaluation of gas hydrate-bearing marine sediments on the Blake Ridge with downhole geochemical log measurements

USGS Publications Warehouse

Collett, T.S.; Wendlandt, R.F.

2000-01-01

The analyses of downhole log data from Ocean Drilling Program (ODP) boreholes on the Blake Ridge at Sites 994, 995, and 997 indicate that the Schlumberger geochemical logging tool (GLT) may yield useful gas hydrate reservoir data. In neutron spectroscopy downhole logging, each element has a characteristic gamma ray that is emitted from a given neutron-element interaction. Specific elements can be identified by their characteristic gamma-ray signature, with the intensity of emission related to the atomic elemental concentration. By combining elemental yields from neutron spectroscopy logs, reservoir parameters including porosities, lithologies, formation fluid salinities, and hydrocarbon saturations (including gas hydrate) can be calculated. Carbon and oxygen elemental data from the GLT was used to determine gas hydrate saturations at all three sites (Sites 994, 995, and 997) drilled on the Blake Ridge during Leg 164. Detailed analyses of the carbon and oxygen content of various sediments and formation fluids were used to construct specialized carbon/oxygen ratio (COR) fan charts for a series of hypothetical gas hydrate accumulations. For more complex geologic systems, a modified version of the standard three-component COR hydrocarbon saturation equation was developed and used to calculate gas hydrate saturations on the Blake Ridge. The COR-calculated gas hydrate saturations (ranging from about 2% to 14% bulk volume gas hydrate) from the Blake Ridge compare favorably to the gas hydrate saturations derived from electrical resistivity log measurements.

Extension of Generalized Fluid System Simulation Program's Fluid Property Database

NASA Technical Reports Server (NTRS)

Patel, Kishan

2011-01-01

This internship focused on the development of additional capabilities for the General Fluid Systems Simulation Program (GFSSP). GFSSP is a thermo-fluid code used to evaluate system performance by a finite volume-based network analysis method. The program was developed primarily to analyze the complex internal flow of propulsion systems and is capable of solving many problems related to thermodynamics and fluid mechanics. GFSSP is integrated with thermodynamic programs that provide fluid properties for sub-cooled, superheated, and saturation states. For fluids that are not included in the thermodynamic property program, look-up property tables can be provided. The look-up property tables of the current release version can only handle sub-cooled and superheated states. The primary purpose of the internship was to extend the look-up tables to handle saturated states. This involves a) generation of a property table using REFPROP, a thermodynamic property program that is widely used, and b) modifications of the Fortran source code to read in an additional property table containing saturation data for both saturated liquid and saturated vapor states. Also, a method was implemented to calculate the thermodynamic properties of user-fluids within the saturation region, given values of pressure and enthalpy. These additions required new code to be written, and older code had to be adjusted to accommodate the new capabilities. Ultimately, the changes will lead to the incorporation of this new capability in future versions of GFSSP. This paper describes the development and validation of the new capability.

Buckling condensation in constrained growth

NASA Astrophysics Data System (ADS)

Dervaux, Julien; Ben Amar, Martine

2011-03-01

The multiple complexities inherent to living objects have motivated the search for abiotic substitutes, able to mimic some of their relevant physical properties. Hydrogels provide a highly monitorable counterpart and have thus found many applications in medicine and bioengineering. Recently, it has been recognized that their ability to swell could be used to unravel some of the universal physical processes at work during biological growth. However, it is yet unknown how the microscopic distinctions between swelling and biological growth affect macroscopic changes (shape, stresses) induced by volume variations. To answer this question, we focus on a clinically motivated example of growth. Some solid tumors such as melanoma or glioblastoma undergo a shape transition during their evolution. This bifurcation appears when growth is confined at the periphery of the tumor and is concomitant with the transition from the avascular to the vascular stage of the tumor evolution. To model this phenomenon, we consider in this paper the deformation of an elastic ring enclosing a core of different stiffness. When the volume of the outer ring increases, the system develops a periodic instability. We consider two possible descriptions of the volume variation process: either by imposing a homogeneous volumetric strain (biological growth) or through migration of solvent molecules inside a solid network (swelling). For thin rings, both theories are in qualitative agreement. When the interior is soft, we predict the emergence of a large wavelength buckling. Upon increasing the stiffness of the inner disc, the wavelength of the instability decreases until a condensation of the buckles occurs at the free boundary. This short wavelength pattern is independent of the stiffness of the disc and is only limited by the presence of surface tension. For thicker rings, two scenarios emerge. When a volumetric strain is prescribed, compressive stresses accumulate in the vicinity of the core and the deformation localizes itself at the boundary between the disc and the ring. On the other hand, swelling being an instance of stress-modulated growth, elastic stretches near the core saturate and the instability occurs primarily at the free boundary. Besides its implications for the mechanical stability of avascular tumors, this work provides important results concerning layered tissues growth and the role of hydrogels as biological tissues substitutes.

Methane Hydrates: Chapter 8

USGS Publications Warehouse

Boswell, Ray; Yamamoto, Koji; Lee, Sung-Rock; Collett, Timothy S.; Kumar, Pushpendra; Dallimore, Scott

2008-01-01

Gas hydrate is a solid, naturally occurring substance consisting predominantly of methane gas and water. Recent scientific drilling programs in Japan, Canada, the United States, Korea and India have demonstrated that gas hydrate occurs broadly and in a variety of forms in shallow sediments of the outer continental shelves and in Arctic regions. Field, laboratory and numerical modelling studies conducted to date indicate that gas can be extracted from gas hydrates with existing production technologies, particularly for those deposits in which the gas hydrate exists as pore-filling grains at high saturation in sand-rich reservoirs. A series of regional resource assessments indicate that substantial volumes of gas hydrate likely exist in sand-rich deposits. Recent field programs in Japan, Canada and in the United States have demonstrated the technical viability of methane extraction from gas-hydrate-bearing sand reservoirs and have investigated a range of potential production scenarios. At present, basic reservoir depressurisation shows the greatest promise and can be conducted using primarily standard industry equipment and procedures. Depressurisation is expected to be the foundation of future production systems; additional processes, such as thermal stimulation, mechanical stimulation and chemical injection, will likely also be integrated as dictated by local geological and other conditions. An innovative carbon dioxide and methane swapping technology is also being studied as a method to produce gas from select gas hydrate deposits. In addition, substantial additional volumes of gas hydrate have been found in dense arrays of grain-displacing veins and nodules in fine-grained, clay-dominated sediments; however, to date, no field tests, and very limited numerical modelling, have been conducted with regard to the production potential of such accumulations. Work remains to further refine: (1) the marine resource volumes within potential accumulations that can be produced through exploratory drilling programs; (2) the tools for gas hydrate detection and characterisation from remote sensing data; (3) the details of gas hydrate reservoir production behaviour through additional, well-monitored and longer duration field tests and (4) the understanding of the potential environmental impacts of gas hydrate resource development. The results of future production tests, in the context of varying market and energy supply conditions around the globe, will be the key to determine the ultimate timing and scale of the commercial production of natural gas from gas hydrates.

Volume Ice Radiolysis in the Outer Solar System

NASA Technical Reports Server (NTRS)

Cooper, John F.; Cooper, Paul D.

2006-01-01

The primary energy flux of charged particle components of the heliospheric and magnetospheric environments of the solar system is primarily carried by highly penetrating energetic particles. Although laboratory experiments on production of organics and oxidants typically only address effects on very thin surface layers, energy deposition occurs on surfaces of icy bodies of the outer solar system to meters in depth. Time scales for significant radiolytic deposition vary from thousands of years at millimeter depths on Europa to billions of years in the meters-deep regolith of Kuiper Belt Objects. Radioisotope decay (e.g., K-40) also contributes to volume radiolysis as the only energy source at much greater depths. Radiolytic oxygen is a potential resource for life within Europa and a partial source of oxygen for Saturn's magnetosphere and Titan's upper atmosphere. Interactions of very high energy cosmic rays with ices at Titan's surface may provide one of the few sources of oxidants in that highly reducing environment. The red colors of low-inclination classical Kuiper Belt Objects at 40-50 AU, and Centaur objects originating from this same population, may arise from volume radiolysis of deep ice layers below more refractory radiation crusts eroded away by surface sputtering and micrometeoroid impacts. A variety of techniques are potentially available to measure volume radiolysis products and have been proposed for study as part of the new Space Physics of Life initiative at NASA Goddard Space Flight Center. The technique of Electron Paramagnetic Resonance (EPR) has been used in medical studies to measure oxidant production in irradiated human tissue for cancer treatment. Other potential techniques include optical absorption spectroscopy and standard wet chemical analysis. These and other potential techniques are briefly reviewed for applicability to problems in solar system ice radiolysis and astrobiology.

Maritime Standards for Compliance Safety and Health Officers (Instructor Manual). Volume 3

DTIC Science & Technology

1981-03-01

and striking tools "o Hamers "o Sledge hsmers "o Riveting hamners. 7. Hazards and health effects associated with the use of hand tools o Loss of eyes...lettered starting at the keel, A-B-C, etc. Strakes are classified inner skin, outer or cover, clinker or in and out, forefoot , shoe, boss, sheer, and

Ratio of prostate specific antigen to the outer gland volume of prostrate as a predictor for prostate cancer.

PubMed

Zhang, Hai-Min; Yan, Yang; Wang, Fang; Gu, Wen-Yu; Hu, Guang-Hui; Zheng, Jun-Hua

2014-01-01

As a definite diagnosis of prostate cancer, puncture biopsy of the prostate is invasive method. The aim of this study was to evaluate the value of OPSAD (the ratio of PSA to the outer gland volume of prostate) as a non-invasive screening and diagnosis method for prostate cancer in a select population. The diagnosis data of 490 subjects undergoing ultrasound-guided biopsy of the prostate were retrospectively analyzed. This included 133 patients with prostate cancer, and 357 patients with benign prostate hyperplasia (BPH). The OPSAD was significantly greater in patients with prostate cancer (1.87 ± 1.26 ng/ml(2)) than those with BPH (0.44 ± 0.21 ng/ml(2)) (P < 0.05). Receiver operating characteristic (ROC) curve analysis revealed that the performance of OPSAD as a diagnostic tool is superior to PSA and PSAD for the diagnosis of prostate cancer. In the different groups divided according to the Gleason score of prostate cancer, OPSAD is elevated with the rise of the Gleason score. OPSAD may be used as a new indicator for the diagnosis and prognosis of prostate cancer, and it can reduce the use of unnecessary puncture biopsy of the prostate.

Spool Valve for Switching Air Flows Between Two Beds

NASA Technical Reports Server (NTRS)

Dean, W. Clark

2005-01-01

U.S. Patent 6,142,151 describes a dual-bed ventilation system for a space suit, with emphasis on a multiport spool valve that switches air flows between two chemical beds that adsorb carbon dioxide and water vapor. The valve is used to alternately make the air flow through one bed while exposing the other bed to the outer-space environment to regenerate that bed through vacuum desorption of CO2 and H2O. Oxygen flowing from a supply tank is routed through a pair of periodically switched solenoid valves to drive the spool valve in a reciprocating motion. The spool valve equalizes the pressures of air in the beds and the volumes of air flowing into and out of the beds during the alternations between the adsorption and desorption phases, in such a manner that the volume of air that must be vented to outer space is half of what it would be in the absence of pressure equalization. Oxygen that has been used to actuate the spool valve in its reciprocating motion is released into the ventilation loop to replenish air lost to vacuum during the previous desorption phase of the operating cycle.

Probabilistic Dynamic Buckling of Smart Composite Shells

NASA Technical Reports Server (NTRS)

Abumeri, Galib H.; Chamis, Christos C.

2003-01-01

A computational simulation method is presented to evaluate the deterministic and nondeterministic dynamic buckling of smart composite shells. The combined use of composite mechanics, finite element computer codes, and probabilistic analysis enable the effective assessment of the dynamic buckling load of smart composite shells. A universal plot is generated to estimate the dynamic buckling load of composite shells at various load rates and probabilities. The shell structure is also evaluated with smart fibers embedded in the plies right below the outer plies. The results show that, on the average, the use of smart fibers improved the shell buckling resistance by about 10 percent at different probabilities and delayed the buckling occurrence time. The probabilistic sensitivities results indicate that uncertainties in the fiber volume ratio and ply thickness have major effects on the buckling load while uncertainties in the electric field strength and smart material volume fraction have moderate effects. For the specific shell considered in this evaluation, the use of smart composite material is not recommended because the shell buckling resistance can be improved by simply re-arranging the orientation of the outer plies, as shown in the dynamic buckling analysis results presented in this report.

Probabilistic Dynamic Buckling of Smart Composite Shells

NASA Technical Reports Server (NTRS)

Chamis, Christos C.; Abumeri, Galib H.

2007-01-01

A computational simulation method is presented to evaluate the deterministic and nondeterministic dynamic buckling of smart composite shells. The combined use of intraply hybrid composite mechanics, finite element computer codes, and probabilistic analysis enable the effective assessment of the dynamic buckling load of smart composite shells. A universal plot is generated to estimate the dynamic buckling load of composite shells at various load rates and probabilities. The shell structure is also evaluated with smart fibers embedded in the plies right next to the outer plies. The results show that, on the average, the use of smart fibers improved the shell buckling resistance by about 10% at different probabilities and delayed the buckling occurrence time. The probabilistic sensitivities results indicate that uncertainties in the fiber volume ratio and ply thickness have major effects on the buckling load while uncertainties in the electric field strength and smart material volume fraction have moderate effects. For the specific shell considered in this evaluation, the use of smart composite material is not recommended because the shell buckling resistance can be improved by simply re-arranging the orientation of the outer plies, as shown in the dynamic buckling analysis results presented in this report.

Cell volumes, maximal growth rates of unicellular algae and ciliates, and the role of ciliates in the marine pelagial

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

Banse, K.

1982-01-01

A review of growth rates of diatoms and dinoflagellates in light-saturated, nutrient-replete cultures at 20/sup 0/C confirms weak dependence on cell volume or mass. These maximal (intrinsic) rates are not linearly related to surface area or surface-to-volume ratio of the cells. The growth of most diatoms is materially faster than that of dinoflagellates; other algae fall in between or below the dinoflagellates. Small ciliates have appreciably higher intrinsic growth rates than algae of the same cell volume. The average food consumption per ciliate in the marine pelagic realm is inferred to be very low, so that the realized specific growthmore » rates are much smaller than the intrinsic potentials. Also, a previously postulated refuge from predation, afforded by small size, is extended down to about 10-..mu..m/sup 3/ cell volume.« less

Synthesis of raspberry-like monodisperse magnetic hollow hybrid nanospheres by coating polystyrene template with Fe(3)O(4)@SiO(2) particles.

PubMed

Wang, Chunlei; Yan, Juntao; Cui, Xuejun; Wang, Hongyan

2011-02-01

In this paper, we present a novel method for the preparation of raspberry-like monodisperse magnetic hollow hybrid nanospheres with γ-Fe(2)O(3)@SiO(2) particles as the outer shell. PS@Fe(3)O(4)@SiO(2) composite nanoparticles were successfully prepared on the principle of the electrostatic interaction between negatively charged silica and positively charged polystyrene, and then raspberry-like magnetic hollow hybrid nanospheres with large cavities were achieved by means of calcinations, simultaneously, the magnetite (Fe(3)O(4)) was transformed into maghemite (γ-Fe(2)O(3)). Transmission electron microscopy (TEM) demonstrated that the obtained magnetic hollow silica nanospheres with the perfect spherical profile were well monodisperse and uniform with the mean size of 253nm. The Fourier transform infrared (FTIR) spectrometry, energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) provided the sufficient evidences for the presence of Fe(3)O(4) in the silica shell. Moreover, the magnetic hollow silica nanospheres possessed a characteristic of superparamagnetic with saturation magnetization value of about 7.84emu/g by the magnetization curve measurement. In addition, the nitrogen adsorption-desorption measurement exhibited that the pore size, BET surface area, pore volume of magnetic hollow silica nanospheres were 3.5-5.5nm, 307m(2)g(-1) and 1.33cm(3)g(-1), respectively. Therefore, the magnetic hollow nanospheres possess a promising future in controlled drug delivery and targeted drug applications. Copyright © 2010 Elsevier Inc. All rights reserved.

Design and Operating Characteristics of High-Speed, Small-Bore Cylindrical-Roller Bearings

NASA Technical Reports Server (NTRS)

Pinel, Stanley, I.; Signer, Hans R.; Zaretsky, Erwin V.

2000-01-01

The computer program SHABERTH was used to analyze 35-mm-bore cylindrical roller bearings designed and manufactured for high-speed turbomachinery applications. Parametric tests of the bearings were conducted on a high-speed, high-temperature bearing tester and the results were compared with the computer predictions. Bearings with a channeled inner ring were lubricated through the inner ring, while bearings with a channeled outer ring were lubricated with oil jets. Tests were run with and without outer-ring cooling. The predicted bearing life decreased with increasing speed because of increased contact stresses caused by centrifugal load. Lower temperatures, less roller skidding, and lower power losses were obtained with channeled inner rings. Power losses calculated by the SHABERTH computer program correlated reasonably well with the test results. The Parker formula for XCAV (used in SHABERTH as a measure of oil volume in the bearing cavity) needed to be adjusted to reflect the prevailing operating conditions. The XCAV formula will need to be further refined to reflect roller bearing lubrication, ring design, cage design, and location of the cage-controlling land.

Localized high-resolution DTI of the human midbrain using single-shot EPI, parallel imaging, and outer-volume suppression at 7 T

PubMed Central

Wargo, Christopher J.; Gore, John C.

2013-01-01

Localized high-resolution diffusion tensor images (DTI) from the midbrain were obtained using reduced field-of-view (rFOV) methods combined with SENSE parallel imaging and single-shot echo planar (EPI) acquisitions at 7 T. This combination aimed to diminish sensitivities of DTI to motion, susceptibility variations, and EPI artifacts at ultra-high field. Outer-volume suppression (OVS) was applied in DTI acquisitions at 2- and 1-mm2 resolutions, b=1000 s/mm2, and six diffusion directions, resulting in scans of 7- and 14-min durations. Mean apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured in various fiber tract locations at the two resolutions and compared. Geometric distortion and signal-to-noise ratio (SNR) were additionally measured and compared for reduced-FOV and full-FOV DTI scans. Up to an eight-fold data reduction was achieved using DTI-OVS with SENSE at 1 mm2, and geometric distortion was halved. The localization of fiber tracts was improved, enabling targeted FA and ADC measurements. Significant differences in diffusion properties were observed between resolutions for a number of regions suggesting that FA values are impacted by partial volume effects even at a 2-mm2 resolution. The combined SENSE DTI-OVS approach allows large reductions in DTI data acquisition and provides improved quality for high-resolution diffusion studies of the human brain. PMID:23541390

Enhancing Energy in Future Conventional Munition

NASA Astrophysics Data System (ADS)

Peiris, Suhithi

2017-06-01

Future conventional weapons are envisioned to contain more energy per volume than current weapons. Current weapons comprise of inert steel outer case, with inner volume for energetic materials, fuzing, sensor package, propulsion system, etc. Recent research on reactive materials (RM) & new energetics, and exploiting additive manufacturing can optimize the use of both mass and volume to achieve much higher energy in future weapons. For instance, replacing inert steel with RM of similar strength, additively manufacturing fuzing packages within the weapon form factor, and combing the whole with new energetics, will enable the same lethality effects from smaller weapons as obtained from today's larger weapons. This paper will elaborate on reactive materials and properties necessary for optimal utilization in various weapon features, and touch on other aspects of enhancing energy in future conventional munition.

Nonlinear asymmetric tearing mode evolution in cylindrical geometry

DOE PAGES

Teng, Qian; Ferraro, N.; Gates, David A.; ...

2016-10-27

The growth of a tearing mode is described by reduced MHD equations. For a cylindrical equilibrium, tearing mode growth is governed by the modified Rutherford equation, i.e., the nonlinear Δ'(w). For a low beta plasma without external heating, Δ'(w) can be approximately described by two terms, Δ' ql(w), Δ'A(w). In this work, we present a simple method to calculate the quasilinear stability index Δ'ql rigorously, for poloidal mode number m ≥ 2. Δ' ql is derived by solving the outer equation through the Frobenius method. Δ'ql is composed of four terms proportional to: constant Δ' 0, w, wlnw, and w2.more » Δ' A is proportional to the asymmetry of island that is roughly proportional to w. The sum of Δ' ql and Δ' A is consistent with the more accurate expression calculated perturbatively. The reduced MHD equations are also solved numerically through a 3D MHD code M3D-C1. The analytical expression of the perturbed helical flux and the saturated island width agree with the simulation results. Lastly, it is also confirmed by the simulation that the Δ' A has to be considered in calculating island saturation.« less

Tunable passively Q-switched erbium-doped fiber laser with Chitosan/MoS2 saturable absorber

NASA Astrophysics Data System (ADS)

Ahmad, H.; Aidit, S. N.; Ooi, S. I.; Tiu, Z. C.

2018-07-01

Chitosan, an organic polymer derived from the outer skeletons of crustacean and in the cell wall of fungi is explored as polymer host to develop thin film saturable absorber (SA). As a polymer, Chitosan shows high thermal stability as well as significant transmission characteristics. The highly transparent polymer serves as a good host for SA materials, and a composite Chitosan/MoS2 thin film is demonstrated to successfully generate stable Q-switched lasing output at operating wavelength of 1561.5 nm. At maximum pump power of 280.5 mW, the generated pulse exhibits maximum pulse repetition rate and pulse energy of 79.4 kHz and 43.69 nJ respectively as well as minimum pulse width of 1.02 μs. The overall efficiency of the laser cavity with the Chitosan/MoS2 thin film SA is approximately 0.93%. These results reflect the outstanding performance of Chitosan/MoS2 SA as compared to other MoS2 SA prepared using mechanical exfoliation and optical deposition technique. Moreover, the Chitosan polymer is shown to be a highly potential host in the SA fabrication process due to its promising performance which is comparable to PVA.

Grey matter volume and cortical structure in Prader-Willi syndrome compared to typically developing young adults.

PubMed

Manning, Katherine E; Tait, Roger; Suckling, John; Holland, Anthony J

2018-01-01

Prader-Willi syndrome (PWS) is a neurodevelopmental disorder of genomic imprinting, presenting with a characteristic overeating disorder, mild to moderate intellectual disability, and a variable range of social and behavioral difficulties. Consequently, widespread alterations in neural structure and developmental and maturational trajectory would be expected. To date, there have been few quantitative and systematic studies of brain morphology in PWS, although alterations of volume and of cortical organisation have been reported. This study aimed to investigate, in detail, the structure of grey matter and cortex in the brain in a sample of young adults with PWS in a well-matched case-controlled analysis. 20 young adults with PWS, aged 19-27 years, underwent multiparameter mapping magnetic resonance imaging sequences, from which measures of grey matter volume, cortical thickness and magnetisation transfer saturation, as a proxy measure of myelination, were examined. These variables were investigated in comparison to a control group of 40 typically developing young adults, matched for age and sex. A voxel-based morphometry analysis identified large and widespread bilateral clusters of both increased and decreased grey matter volume in the brain in PWS. In particular, widespread areas of increased volume encompassed parts of the prefrontal cortex, especially medially, the majority of the cingulate cortices, from anterior to posterior aspects, insula cortices, and areas of the parietal and temporal cortices. Increased volume was also reported in the caudate, putamen and thalamus. The most ventromedial prefrontal areas, in contrast, showed reduced volume, as did the parts of the medial temporal lobe, bilateral temporal poles, and a small cluster in the right lateral prefrontal cortex. Analysis of cortical structure revealed that areas of increased volume in the PWS group were largely driven by greater cortical thickness. Conversely, analysis of myelin content using magnetisation transfer saturation indicated that myelination of the cortex was broadly similar in the PWS and control groups, with the exception of highly localised areas, including the insula. The bilateral nature of these abnormalities suggests a systemic biological cause, with possible developmental and maturational mechanisms discussed, and may offer insight into the contribution of imprinted genes to neural development.

Analysis of the convective evaporation of nondilute clusters of drops

NASA Technical Reports Server (NTRS)

Bellan, J.; Harstad, K.

1987-01-01

The penetration distance of an outer flow into a drop cluster volume is the critical, evaporation mode-controlling parameter in the present model for nondilute drop clusters' convective evaporation. The model is found to perform well for such low penetration distances as those obtained for dense clusters in hot environments and low relative velocities between the outer gases and the cluster. For large penetration distances, however, the predictive power of the model deteriorates; in addition, the evaporation time is found to be a weak function of the initial relative velocity and a strong function of the initial drop temperature. The results generally show that the interior drop temperature was transient throughout the drop lifetime, although temperature nonuniformities persisted up to the first third of the total evaporation time at most.

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

Favorite, Jeffrey A.

In transport theory, adjoint-based partial derivatives with respect to mass density are constant-volume derivatives. Likewise, adjoint-based partial derivatives with respect to surface locations (i.e., internal interface locations and the outer system boundary) are constant-density derivatives. This study derives the constant-mass partial derivative of a response with respect to an internal interface location or the outer system boundary and the constant-mass partial derivative of a response with respect to the mass density of a region. Numerical results are given for a multiregion two-dimensional (r-z) cylinder for three very different responses: the uncollided gamma-ray flux at an external detector point, k effmore » of the system, and the total neutron leakage. Finally, results from the derived formulas compare extremely well with direct perturbation calculations.« less

Inflatable nested toroid structure

NASA Technical Reports Server (NTRS)

Johnson, Christopher J. (Inventor); Raboin, Jasen L. (Inventor); Spexarth, Gary R. (Inventor)

2011-01-01

An inflatable structure comprises at least two generally toroidal, inflatable modules. When in a deployed mode, the first, inner module has a major diameter less than that of a second, outer module and is positioned within the inner circumference of the outer module such that the first module is nested circumferentially alongside the second module. The inflatable structure, in a non-deployed, non-inflated mode, is of compact configuration and adapted to be transported to a site of deployment. When deployed, the inflatable structure is of substantially increased interior volume. In one embodiment, access between the interior of the first module and the second module is provided by at least one port or structural pass-through. In another embodiment, the inflatable structure includes at least one additional generally toroidal module external of and circumferentially surrounding the second module.

Adjoint-based constant-mass partial derivatives

DOE PAGES

Favorite, Jeffrey A.

2017-09-01

In transport theory, adjoint-based partial derivatives with respect to mass density are constant-volume derivatives. Likewise, adjoint-based partial derivatives with respect to surface locations (i.e., internal interface locations and the outer system boundary) are constant-density derivatives. This study derives the constant-mass partial derivative of a response with respect to an internal interface location or the outer system boundary and the constant-mass partial derivative of a response with respect to the mass density of a region. Numerical results are given for a multiregion two-dimensional (r-z) cylinder for three very different responses: the uncollided gamma-ray flux at an external detector point, k effmore » of the system, and the total neutron leakage. Finally, results from the derived formulas compare extremely well with direct perturbation calculations.« less

Pulse oximetry in the pulmonary tissue for the non-invasive measurement of mixed venous oxygen saturation.

PubMed

Nitzan, Meir; Nitzan, Itamar

2013-08-01

The oxygen saturation of the systemic arterial blood is associated with the adequacy of respiration, and can be measured non-invasively by pulse oximetry in the systemic tissue. The oxygen saturation of the blood in the pulmonary artery, the mixed venous blood, reflects the balance between oxygen supply to the systemic tissues and their oxygen demand. The mixed venous oxygen saturation has also clinical significance because it is used in Fick equation for the quantitative measurement of cardiac output. At present the measurement of the mixed venous oxygen saturation is invasive and requires insertion of a Swan-Ganz catheter into the pulmonary artery. We suggest a noninvasive method for the measurement of the mixed venous oxygen saturation in infants, pulmonary pulse oximetry. The method is similar to the systemic pulse oximetry, which is based on the different light absorption curves of oxygenated and deoxygenated hemoglobin and on the analysis of photoplethysmographic curves in two wavelengths. The proposed pulmonary pulse oximeter includes light-sources of two wavelengths in the infrared, which illuminate the pulmonary tissue through the thoracic wall. Part of the light which is scattered back from the pulmonary tissue and passes through the thoracic wall is detected, and for each wavelength a pulmonary photoplethysmographic curve is obtained. The pulmonary photoplethysmographic curves reflect blood volume increase during systole in the pulmonary arteries in the lung tissue, which contain mixed venous blood. The ratio R of the amplitude-to-baseline ratio for the two wavelengths is related to the mixed venous oxygen saturation through equations derived for the systemic pulse oximetry. The method requires the use of extinction coefficients values for oxygenated and deoxygenated hemoglobin, which can be found in the literature. Copyright © 2013 Elsevier Ltd. All rights reserved.

Quantitative degassing of gas hydrate-bearing pressure cores from Green Canyon 955, Gulf of Mexico

NASA Astrophysics Data System (ADS)

Phillips, S. C.; Holland, M. E.; Flemings, P. B.; Schultheiss, P. J.; Waite, W. F.; Petrou, E. G.; Jang, J.; Polito, P. J.; O'Connell, J.; Dong, T.; Meazell, K.

2017-12-01

We present results from 20 quantitative degassing experiments of pressure-core sections collected during Expedition UT-GOM2-1 from Green Canyon 955 in the northern Gulf of Mexico. These experiments highlight an average pore-space methane hydrate saturation, Sh, of 59% (min: 12%; max 87%) in sediments between 413 and 440 mbsf in 2032 m water depth. There is a strong lithofacies control of hydrate saturation within the reservoir, with a high saturation sandy silt facies (Sh of 65 to 87%) interbedded with a low saturation clayey silt facies (Sh of 12 to 30%). Bedding occurs on the scale of tens of centimeters. Outside of the main hydrate reservoir, methane hydrate occurs in low saturations (Sh of 0.8 to 3%). Hydrate saturations exhibit a strong correlation (R2=0.89) with the average P-wave velocity measured through the degassed sections. These preliminary hydrate saturations were calculated assuming a porosity of 40% with core filling the full internal diameter of the core liner. Gas recovered during these experiments is composed of almost entirely methane, with an average of 94 ppm ethane and detectable, but not quantifiable, propane. Degassed pressure cores were depressurized through a manifold by the stepwise release of fluid, and the volumes of produced gas and water were monitored. The core's hydrostatic pressure was measured and recorded continuously at the manifold. Pressure and temperature were also measured by data storage tags within the sample chambers. Two slow, multi-day degassing experiments were performed to estimate the in situ salinity within core sections. Based on temperature and pressure observations at the point of the initial pressure rebound due to hydrate dissociation, we estimate the salinity within these samples to be between 33 and 42 g kg-1.

Wettability effect on capillary trapping of supercritical CO2 at pore-scale: micromodel experiment and numerical modeling

NASA Astrophysics Data System (ADS)

Hu, R.; Wan, J.

2015-12-01

Wettability of reservoir minerals along pore surfaces plays a controlling role in capillary trapping of supercritical (sc) CO2 in geologic carbon sequestration. The mechanisms controlling scCO2 residual trapping are still not fully understood. We studied the effect of pore surface wettability on CO2 residual saturation at the pore-scale using engineered high pressure and high temperature micromodel (transparent pore networks) experiments and numerical modeling. Through chemical treatment of the micromodel pore surfaces, water-wet, intermediate-wet, and CO2-wet micromodels can be obtained. Both drainage and imbibition experiments were conducted at 8.5 MPa and 45 °C with controlled flow rate. Dynamic images of fluid-fluid displacement processes were recorded using a microscope with a CCD camera. Residual saturations were determined by analysis of late stage imbibition images of flow path structures. We performed direct numerical simulations of the full Navier-Stokes equations using a volume-of-fluid based finite-volume framework for the primary drainage and the followed imbibition for the micromodel experiments with different contact angles. The numerical simulations agreed well with our experimental observations. We found that more scCO2 can be trapped within the CO2-wet micromodel whereas lower residual scCO2 saturation occurred within the water-wet micromodels in both our experiments and the numerical simulations. These results provide direct and consistent evidence of the effect of wettability, and have important implications for scCO2 trapping in geologic carbon sequestration.

Controls on the physical properties of gas-hydrate-bearing sediments because of the interaction between gas hydrate and porous media

USGS Publications Warehouse

Lee, Myung W.; Collett, Timothy S.

2005-01-01

Physical properties of gas-hydrate-bearing sediments depend on the pore-scale interaction between gas hydrate and porous media as well as the amount of gas hydrate present. Well log measurements such as proton nuclear magnetic resonance (NMR) relaxation and electromagnetic propagation tool (EPT) techniques depend primarily on the bulk volume of gas hydrate in the pore space irrespective of the pore-scale interaction. However, elastic velocities or permeability depend on how gas hydrate is distributed in the pore space as well as the amount of gas hydrate. Gas-hydrate saturations estimated from NMR and EPT measurements are free of adjustable parameters; thus, the estimations are unbiased estimates of gas hydrate if the measurement is accurate. However, the amount of gas hydrate estimated from elastic velocities or electrical resistivities depends on many adjustable parameters and models related to the interaction of gas hydrate and porous media, so these estimates are model dependent and biased. NMR, EPT, elastic-wave velocity, electrical resistivity, and permeability measurements acquired in the Mallik 5L-38 well in the Mackenzie Delta, Canada, show that all of the well log evaluation techniques considered provide comparable gas-hydrate saturations in clean (low shale content) sandstone intervals with high gas-hydrate saturations. However, in shaly intervals, estimates from log measurement depending on the pore-scale interaction between gas hydrate and host sediments are higher than those estimates from measurements depending on the bulk volume of gas hydrate.

UNDERSTANDING AND MANAGING RISKS POSED BY BRINES CONTAINING DISSOLVED CARBON DIOXIDE

EPA Science Inventory

Geologic disposal of supercritical carbon dioxide in saline aquifers and depleted oil and gas fields will cause large volumes of brine to become saturated with dissolved CO₂ at concentrations of 50 g/l or more.  As CO₂ dissolves in brine, the brine de...

Offline Solid-phase Extraction Large-volume Injection-Gas chromatography for the Analysis of Mineral Oil-saturated Hydrocarbons in Commercial Vegetable Oils.

PubMed

Liu, Lingling; Huang, Hua; Wu, Yanwen; Li, Bingning; Ouyang, Jie

2017-09-01

An offline solid-phase extraction (SPE) approach combined with a large-volume injection (LVI)-gas chromatography-flame ionization detector (LVI-GC-FID) is improved for routine analysis of mineral oil saturated hydrocarbons (MOSH) in vegetable oils. The key procedure of the method consists in using offline SPE columns for MOSH purification. The SPE column packed with 1% Ag-activated silica gel was used to separate MOSH from triglycerides and olefins in variety of vegetable oils. The eluent of MOSH fraction was only 3 mL and the concentration step was quick with little evaporation loss. The limit of quantification (LOQ) of the method was 2.5 mg/kg and the linearity ranged from 2 to 300 mg/kg. The accuracy was assessed by measuring the recoveries from spiked oil samples and was higher than 90%. Twenty-seven commercial vegetable oils were analyzed, and different levels of MOSH contamination were detected with the highest being 259.4 mg/kg. The results suggested that it is necessary to routinely detect mineral oil contamination in vegetable oils for food safety.

Northeastern Gulf of Mexico coastal and marine ecosystem program: Data search and synthesis, annotated bibliography. Appendix A: Physical oceanography. Final report

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

NONE

This study summarizes environmental and socioeconomic information related to the Florida Panhandle Outer Continental Shelf (OCS). It contains a conceptual model of active processes and identification of information gaps that will be useful in the design of future environmental studies in the geographic area. The annotated bibliography for this study is printer in six volumes, each pertaining to a specific topic. They are as follows: Appendix A--Physical Oceanography; Appendix B--Meteorology; Appendix C--Geology; Appendix D--Chemistry; Appendix E--Biology; and Appendix F--Socioeconomics. This volume contains bibliographic references pertaining to physical oceanography.

Dense modifiable interconnections utilizing photorefractive volume holograms

NASA Astrophysics Data System (ADS)

Psaltis, Demetri; Qiao, Yong

1990-11-01

This report describes an experimental two-layer optical neural network built at Caltech. The system uses photorefractive volume holograms to implement dense, modifiable synaptic interconnections and liquid crystal light valves (LCVS) to perform nonlinear thresholding operations. Kanerva's Sparse, Distributed Memory was implemented using this network and its ability to recognize handwritten character-alphabet (A-Z) has been demonstrated experimentally. According to Kanerva's model, the first layer has fixed, random weights of interconnections and the second layer is trained by sum-of-outer-products rule. After training, the recognition rates of the network on the training set (104 patterns) and test set (520 patterns) are 100 and 50 percent, respectively.

3-D Distribution of Retained Colloids in Unsaturated Porous Media

NASA Astrophysics Data System (ADS)

Morales, V. L.; Perez-Reche, F. J.; Holzner, M.; Kinzelbach, W. K.; Otten, W.

2013-12-01

It is well accepted that colloid transport processes in porous media differ substantially between water saturated and unsaturated conditions. Differences are frequently ascribed to colloid immobilization by association with interfaces with the gas, as well as to restrictions of the liquid medium through which colloids are transported. Such factors depend on interfacial conditions provided by the water saturation of the porous medium. Yet, the current understanding of the importance of colloid retention at gas interfaces is based on observations of single pores or two-dimensional pore network representations, leaving open the question of their statistical significance when all pores in the medium are considered. In order to address this question, column experiments were performed using a model porous medium of glass beads through which colloidal silver particles were transported for conditions of varying water content. X-ray microtomography was subsequently employed as a non-destructive imaging technique to obtain pore-scale information of the entire column regarding: i) the presence and distribution of the four main locations where colloids can become retained (interfaces with the liquid-solid, gas-liquid and gas-solid, and the bulk liquid), ii) deposition profiles of colloids along the column classified by the available retention location, iii) morphological characteristics of the deposited colloidal aggregates, and iv) channel widths of 3-dimensional pore-water network representations. The results presented provide, for the first time, a direct statistical evaluation on the significance of colloid retention by attachment to the liquid-solid, gas-liquid, gas-solid interfaces, and by straining in the bulk liquid. Additionally, an effective-pore structure characteristic is proposed to improve predictions of mass removal by straining under various water saturations. A) Unsaturated conditions. B) Saturated conditions. Left: Tomograph slice illustrating with false coloring Regions Of Interest corresponding to retention locations at the gas-liquid (purple), gas-solid (white) and solid-liquid interface (blue), and the bulk liquid (teal). Right: Deposition profiles of silver colloids (Ag) per retention location (T: total, GLI: gas-liquid interface, GSI: gas-solid interface, SLI: solid-liquid interface, L: bulk liquid) (Top). Depth profiles of the volume occupied by each retention location (Middle). Normalized deposition profiles of silver volume retained by its corresponding retention-location volume (Bottom).

Variation of saturation effect in the ionospheric F2 critical frequency at low latitude

NASA Astrophysics Data System (ADS)

Ikubanni, S. O.; Adeniyi, J. O.

2013-08-01

Saturation in the dependence of foF2 on solar flux is a phenomenon more pronounced in the equatorial ionization anomaly region. The phenomenon was observed in the relationship between the F2 critical frequency (foF2) and any solar indices. Using a two-segmented regression fit on data from an African low latitude station (Geographical Latitude 12.4°N; Geomagnetic latitude 3.5°N), saturation features from the dependence of foF2 on solar radio flux (F10.7) was studied. Diurnal and seasonal variation were studied for the first time in this low latitude region of the African sector. Significant variations were observed, especially in the solstices. It was observed that saturation effect is closely related to the hourly F2 critical frequency and these results were compared with those from Asian, Australian and the American sectors. The diurnal and seasonal variations find their explanations in the photo-ionization process, the fountain effect, and the pre-reversal enhancement while the seasonal variation was attributed to both the ion drift and thermospheric circulation. Future work with larger volume of data is expected to validate the observations from this study.

Spin-glass-like freezing of inner and outer surface layers in hollow γ-Fe 2O 3 nanoparticles

DOE PAGES

Khurshid, Hafsa; Lampen-Kelley, Paula; Iglesias, Òscar; ...

2015-10-27

Disorder among surface spins largely dominates the magnetic response of ultrafine magnetic particle systems. In this work, we examine time-dependent magnetization in high-quality, monodisperse hollow maghemite nanoparticles (NPs) with a 14.8±0.5 nm outer diameter and enhanced surface-to-volume ratio. The nanoparticle ensemble exhibits spin-glass-like signatures in dc magnetic aging and memory protocols and ac magnetic susceptibility. The dynamics of the system slow near 50 K, and becomes frozen on experimental time scales below 20 K. Remanence curves indicate the development of magnetic irreversibility concurrent with the freezing of the spin dynamics. A strong exchange-bias effect and its training behavior point tomore » highly frustrated surface spins that rearrange much more slowly than interior spins with bulk coordination. Monte Carlo simulations of a hollow particle reproducing the experimental morphology corroborate strongly disordered surface layers with complex energy landscapes that underlie both glass-like dynamics and magnetic irreversibility. Calculated hysteresis loops reveal that magnetic behavior is not identical at the inner and outer surfaces, with spins at the outer surface layer of the 15 nm hollow particles exhibiting a higher degree of frustration. Lastly, our combined experimental and simulated results shed light on the origin of spin-glass-like phenomena and the important role played by the surface spins in magnetic hollow nanostructures.« less

Spin-glass-like freezing of inner and outer surface layers in hollow γ-Fe2O3 nanoparticles

PubMed Central

Khurshid, Hafsa; Lampen-Kelley, Paula; Iglesias, Òscar; Alonso, Javier; Phan, Manh-Huong; Sun, Cheng-Jun; Saboungi, Marie-Louise; Srikanth, Hariharan

2015-01-01

Disorder among surface spins is a dominant factor in the magnetic response of magnetic nanoparticle systems. In this work, we examine time-dependent magnetization in high-quality, monodisperse hollow maghemite nanoparticles (NPs) with a 14.8 ± 0.5 nm outer diameter and enhanced surface-to-volume ratio. The nanoparticle ensemble exhibits spin-glass-like signatures in dc magnetic aging and memory protocols and ac magnetic susceptibility. The dynamics of the system slow near 50 K, and become frozen on experimental time scales below 20 K. Remanence curves indicate the development of magnetic irreversibility concurrent with the freezing of the spin dynamics. A strong exchange-bias effect and its training behavior point to highly frustrated surface spins that rearrange much more slowly than interior spins. Monte Carlo simulations of a hollow particle corroborate strongly disordered surface layers with complex energy landscapes that underlie both glass-like dynamics and magnetic irreversibility. Calculated hysteresis loops reveal that magnetic behavior is not identical at the inner and outer surfaces, with spins at the outer surface layer of the 15 nm hollow particles exhibiting a higher degree of frustration. Our combined experimental and simulated results shed light on the origin of spin-glass-like phenomena and the important role played by the surface spins in magnetic hollow nanostructures. PMID:26503506

Torus models of the outer disc of the Milky Way using LAMOST survey data

NASA Astrophysics Data System (ADS)

Wang, Qiao; Wang, Yougang; Liu, Chao; Mao, Shude; Long, R. J.

2017-09-01

With a sample of 48 161 K giant stars selected from the LAMOST DR 2 catalogue, we construct torus models in a large volume extending, for the first time, from the solar vicinity to a Galactocentric distance of ∼20 kpc, reaching the outskirts of the Galactic disc. We show that the kinematics of the K giant stars match conventional models, e.g. as created by Binney in 2012, in the Solar vicinity. However such two-disc models fail if they are extended to the outer regions, even if an additional disc component is utilized. If we loosen constraints in Sun's vicinity, we find that an effective thick disc model could explain the anticentre of the MW. The Large Area Multi-Object Spectroscopic Telescope data imply that the sizes of the Galactic discs are much larger, and that the outer disc is much thicker, than previously thought, or alternatively that the outer structure is not a conventional disc at all. However, the velocity dispersion σ0z of the kinematically thick disc in the best-fitting model is about 80 km s-1 and has a scale parameter Rσ for an exponential distribution function of ∼19 kpc. Such a height σ0z is strongly rejected by current measurements in the solar neighbourhood, and thus a model beyond quasi-thermal, two or three thin or thick discs is required.

Quantifying the water storage volume of major aquifers in the US

NASA Astrophysics Data System (ADS)

Jame, S. A.; Bowling, L. C.

2017-12-01

Groundwater is one of our most valuable natural resources which affects not only the food and energy nexus, but ecosystem and human health, through the availability of drinking water. Quantification of current groundwater storage is not only required to better understand groundwater flow and its role in the hydrologic cycle, but also sustainable use. In this study, a new high resolution map (5' minutes) of groundwater properties is created for US major aquifers to provide an estimate of total groundwater storage. The estimation was done using information on the spatial extent of the principal aquifers of the US from the USGS Groundwater Atlas, the average porosity of different hydrolithologic groups and the current saturated thickness of each aquifer. Saturated thickness varies within aquifers, and has been calculated by superimposing current water-table contour maps over the base aquifer altitude provided by USGS. The average saturated thickness has been computed by interpolating available data on saturated thickness for an aquifer using the kriging method. Total storage of aquifers in each cell was then calculated by multiplying the spatial extent, porosity, and thickness of the saturated layer. The resulting aquifer storage estimates was compared with current groundwater withdrawal rates to produce an estimate of how many years' worth of water are stored in the aquifers. The resulting storage map will serve as a national dataset for stakeholders to make decisions for sustainable use of groundwater.

Relationship of grey and white matter abnormalities with distance from the surface of the brain in multiple sclerosis.

PubMed

Pardini, Matteo; Sudre, Carole H; Prados, Ferran; Yaldizli, Özgür; Sethi, Varun; Muhlert, Nils; Samson, Rebecca S; van de Pavert, Steven H; Cardoso, M Jorge; Ourselin, Sebastien; Gandini Wheeler-Kingshott, Claudia A M; Miller, David H; Chard, Declan T

2016-11-01

To assess the association between proximity to the inner (ventricular and aqueductal) and outer (pial) surfaces of the brain and the distribution of normal appearing white matter (NAWM) and grey matter (GM) abnormalities, and white matter (WM) lesions, in multiple sclerosis (MS). 67 people with relapse-onset MS and 30 healthy controls were included in the study. Volumetric T1 images and high-resolution (1 mm 3 ) magnetisation transfer ratio (MTR) images were acquired and segmented into 12 bands between the inner and outer surfaces of the brain. The first and last bands were discarded to limit partial volume effects with cerebrospinal fluid. MTR values were computed for all bands in supratentorial NAWM, cerebellar NAWM and brainstem NA tissue, and deep and cortical GM. Band WM lesion volumes were also measured. Proximity to the ventricular surfaces was associated with progressively lower MTR values in the MS group but not in controls in supratentorial and cerebellar NAWM, brainstem NA and in deep and cortical GM. The density of WM lesions was associated with proximity to the ventricles only in the supratentorial compartment, and no link was found with distance from the pial surfaces. In MS, MTR abnormalities in NAWM and GM are related to distance from the inner and outer surfaces of the brain, and this suggests that there is a common factor underlying their spatial distribution. A similar pattern was not found for WM lesions, raising the possibility that different factors promote their formation. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Variable Permanent Magnet Quadrupole

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

Mihara, T.; Iwashita, Y.; /Kyoto U.

A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four partsmore » and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.« less

Post-assembly magnetization of a 100 kW high speed permanent magnet rotor.

PubMed

Lv, Yiliang; Wang, Guobin; Li, Liang

2015-03-01

A post-assembly magnetizing fixture has been designed and successfully used to magnetize the rotor of a 100 kW high speed permanent magnet synchronous motor. The rotor is a solid cylinder with outer diameter of 80 mm and total length of 515 mm. The permanent magnet material is samarium-cobalt (Sm2Co17) with saturation magnetizing field of 6 T. The mechanical stability of the magnetizing fixture has been studied as well as the general design methodology. The magnetizing coil is subdivided in order to reduce the electromagnetic force, and the coils are separately reinforced in different ways. The electromagnetic and structural optimization is performed by finite element analysis and verified by experiments.

Application of NIR spectroscopy in the assessment of diabetic foot disorders

NASA Astrophysics Data System (ADS)

Schleicher, Eckhard; Hampel, Uwe; Freyer, Richard

2001-10-01

Diabetic foot syndrome (DFS) is a common sequel of long-term diabetes mellitus. There is a urgent need of noninvasive, objective and quantitative diagnostic tools to assess tissue viability and perfusion for a successful therapy. NIR spectroscopy seems to be qualified to measure local capillary hemoglobin saturation of the outer extremities in patients with progressive diabetic disorders. We investigate how NIR spectroscopy can be applied to the assessment of diabetic foot problems such as neuropathy and angiopathy. Thereby we use spatially resolved spectroscopy in conjunction with a specially developed continuous-wave laser spectrometer. Comparison of intra- and interindividual measurements is expected to yield quantitative measures of local tissue viability which is a prerequisite for a successful therapy.

Studies in Intelligence. Volume 56, Number 1

DTIC Science & Technology

2012-03-01

Leap Forward) Japan (post- Fukushima Daiichi ) Burma (outer provinces) Cambodia (post-Khmer Rouge) On State Instability 18 Studies in Intelligence Vol...March 2012) Center for the Study of Intelligence Products or Outputs?: Probing the Implications of Changing the Outputs of Intelligence Following Trends...Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a

Lightweight Solar Photovoltaic Blankets

NASA Technical Reports Server (NTRS)

Ceragioli, R.; Himmler, R.; Nath, P.; Vogeli, C.; Guha, S.

1995-01-01

Lightweight, flexible sheets containing arrays of stacked solar photovoltaic cells developed to supply electric power aboard spacecraft. Solar batteries satisfying stringent requirements for operation in outer space also adaptable to terrestrial environment. Attractive for use as long-lived, portable photovoltaic power sources. Cells based on amorphous silicon which offers potential for order-of-magnitude increases in power per unit weight, power per unit volume, and endurance in presence of ionizing radiation.

Effect of emulsifier type and concentration, aqueous phase volume and wax ratio on physical, material and mechanical properties of water in oil lipsticks.

PubMed

Beri, A; Norton, J E; Norton, I T

2013-12-01

Water-in-oil emulsions in lipsticks could have the potential to improve moisturizing properties and deliver hydrophilic molecules to the lips. The aims of this work were (i) to investigate the effect of emulsifier type (polymer vs. monomer, and saturated vs. unsaturated chain) and concentration on droplet size and (ii) to investigate the effect of wax ratio (carnauba wax, microcrystalline wax, paraffin wax and performalene) and aqueous phase volume on material properties (Young's modulus, point of fracture, elastic modulus and viscous modulus). Emulsion formation was achieved using a high shear mixer. Results showed that the saturated nature of the emulsifier had very little effect on droplet size, neither did the use of an emulsifier with a larger head group (droplet size ~18-25 μm). Polyglycerol polyricinoleate (PGPR) resulted in emulsions with the smallest droplets (~3-5 μm), as expected from previous studies that show that it produces a thick elastic interface. The results also showed that both Young's modulus and point of fracture increase with increasing percentage of carnauba wax (following a power law dependency of 3), but decrease with increasing percentage of microcrystalline wax, suggesting that the carnauba wax is included in the overall wax network formed by the saturated components, whereas the microcrystalline wax forms irregular crystals that disrupt the overall wax crystal network. Young's modulus, elastic modulus and viscous modulus all decrease with increasing aqueous phase volume in the emulsions, although the slope of the decrease in elastic and viscous moduli is dependent on the addition of solid wax, as a result of strengthening the network. This work suggests the potential use for emulsions in lipstick applications, particularly when PGPR is used as an emulsifier, and with the addition of solid wax, as it increases network strength. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Questa Baseline and Pre-Mining Ground-Water Quality Investigation. 24. Seismic Refraction Tomography for Volume Analysis of Saturated Alluvium in the Straight Creek Drainage and Its Confluence With Red River, Taos County, New Mexico

USGS Publications Warehouse

Powers, Michael H.; Burton, Bethany L.

2007-01-01

As part of a research effort directed by the New Mexico Environment Department to determine pre-mining water quality of the Red River at a molybdenum mining site in northern New Mexico, we used seismic refraction tomography to create subsurface compressional-wave velocity images along six lines that crossed the Straight Creek drainage and three that crossed the valley of Red River. Field work was performed in June 2002 (lines 1-4) and September 2003 (lines 5-9). We interpreted the images to determine depths to the water table and to the top of bedrock. Depths to water and bedrock in boreholes near the lines correlate well with our interpretations based on seismic data. In general, the images suggest that the alluvium in this area has a trapezoidal cross section. Using a U.S. Geological Survey digital elevation model grid of surface elevations of this region and the interpreted elevations to water table and bedrock obtained from the seismic data, we generated new models of the shape of the buried bedrock surface and the water table through surface interpolation and extrapolation. Then, using elevation differences between the two grids, we calculated volumes of dry and wet alluvium in the two drainages. The Red River alluvium is about 51 percent saturated, whereas the much smaller volume of alluvium in the tributary Straight Creek is only about 18 percent saturated. When combined with average ground-water velocity values, the information we present can be used to determine discharge of Straight Creek into Red River relative to the total discharge of Red River moving past Straight Creek. This information will contribute to more accurate models of ground-water flow, which are needed to determine the pre-mining water quality in the Red River.

Evaluating dynamic contrast-enhanced and photoacoustic CT to assess intra-tumor heterogeneity in xenograft mouse models

NASA Astrophysics Data System (ADS)

Stantz, Keith M.; Liu, Bo; Cao, Minsong; Reinecke, Dan; Dzemidzic, Mario; Liang, Yun; Kruger, Robert

2006-03-01

Purpose: To evaluate photoacoustic CT spectroscopy (PCT-S) and dynamic contrast-enhanced CT (DCE-CT) ability to measure parameters - oxygen saturation and vascular physiology - associated with the intra-tumor oxygenation status. Material and Methods: Breast (VEGF165 enhance MCF-7) and ovarian (SKOV3x) cancer cells were implanted into the fat pads and flanks of immune deficient mice and allowed to grow to a diameter of 8-15 mm. CT was used to determine physiological parameters by acquiring a sequence of scans over a 10 minute period after an i.v. injection of a radio-opaque contrast agent (Isovue). These time-dependent contrast-enhanced curves were fit to a two-compartmental model determining tumor perfusion, fractional plasma volume, permeability-surface area produce, and fractional interstitial volume on a voxel-by-voxel basis. After which, the tumors were imaged using photoacoustic CT (Optosonics, Inc., Indianapolis, IN 46202). The near infrared spectra (700-910 nm) within the vasculature was fit to linear combination of measured oxy- and deoxy-hemoglobin blood samples to obtain oxygen saturation levels (SaO II). Results: The PCT-S scanner was first calibrated using different samples of oxygenated blood, from which a statistical error ranging from 2.5-6.5% was measured and a plot of the hemoglobin dissociation curve was consistent with empirical formula. In vivo determination of tumor vasculature SaO II levels were measurably tracked, and spatially correlated to the periphery of the tumor. Tumor depend variations in SaO II - 0.32 (ovarian) and 0.60 (breast) - and in vascular physiology - perfusion, 1.03 and 0.063 mL/min/mL, and fractional plasma volume, 0.20 and 0.07 - were observed. Conclusion: Combined, PCT-S and CED-CT has the potential to measure intra-tumor levels of tumor oxygen saturation and vascular physiology, key parameters associated with hypoxia.

Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning.

PubMed

Soltani, Motahareh; Shetab-Boushehri, Seyed F; Shetab-Boushehri, Seyed V

2016-08-01

Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Activated charcoal significantly reduced the volume of released gas (P <0.01). Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01). A gaseous adduct was formed in the reaction between pure AlP and boric acid. These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning.

Modelling the migration of contaminants through variably saturated dual-porosity, dual-permeability chalk.

PubMed

Brouyère, Serge

2006-01-10

In the Hesbaye region in Belgium, tracer tests performed in variably saturated fissured chalk rocks presented very contrasting results in terms of transit times, according to artificially controlled water recharge conditions prevailing during the experiments. Under intense recharge conditions, tracers migrated across the partially or fully saturated fissure network, at high velocity in accordance with the high hydraulic conductivity and low effective porosity (fracture porosity). At the same time, a portion of the tracer was temporarily retarded in the almost immobile water located in the matrix. Under natural infiltration conditions, the fissure network remained inactive. Tracers migrated downward through the matrix, at low velocity in relation with the low hydraulic conductivity and the large porosity of the matrix. Based on these observations, Brouyère et al. (2004a) [Brouyère, S., Dassargues, A., Hallet, V., 2004a. Migration of contaminants through the unsaturated zone overlying the Hesbaye chalky aquifer in Belgium: a field investigation, J. Contam. Hydrol., 72 (1-4), 135-164, doi: 10.1016/j.conhyd.2003.10.009] proposed a conceptual model in order to explain the migration of solutes in variably saturated, dual-porosity, dual-permeability chalk. Here, mathematical and numerical modelling of tracer and contaminant migration in variably saturated fissured chalk is presented, considering the aforementioned conceptual model. A new mathematical formulation is proposed to represent the unsaturated properties of the fissured chalk in a more dynamic and appropriate way. At the same time, the rock water content is partitioned between mobile and immobile water phases, as a function of the water saturation of the chalk rock. The groundwater flow and contaminant transport in the variably saturated chalk is solved using the control volume finite element method. Modelling the field tracer experiments performed in the variably saturated chalk shows the adequacy and usefulness of the new conceptual, mathematical and numerical model.

Quantitative measurement of channel-block hydraulic interactions by experimental saturation of a large, natural, fissured rock mass.

PubMed

Guglielmi, Y; Mudry, J

2001-01-01

The hydrodynamic behavior of fissured media relies on the relationships between a few very conductive fractures (channels) and the remaining low-conductivity fractures and matrix (blocks). We made a quantitative measurement of those relationships and their effect on water drainage and storage in a 19,000 m3 natural reservoir consisting of karstified limestones. This reservoir was artificially saturated with water by closing a water gate on the main outlet during a varying time (delta t) fixed by the operator. The water gate was completely or partly closed until the water pressure reached a particular specified value. If the water gate was left completely closed long enough, the water pressure was fixed by the elevation of temporary outlets at the site boundaries. The water elevation within the reservoir was monitored by means of pressure cells located on single fractures representative of the bedding plane and the two families of fractures of the massif network. The comparison of pressure variations with the network geometry allows us to identify a typical double permeability characterized by a few very conductive channels along 10 vertical faults. These channels limit blocks consisting of low-conductivity bedding planes and a rather impervious matrix. Depending on the closure interval, delta t, of the water gate, the total volume of water stored in the reservoir can vary from 0.8 m3 (delta t = 5 minutes) to 18.6 m3 (delta t = 2 days). Such a variance of storage versus closure time is explained by the reservoir's double permeability that is characterized by blocks that saturate much more slowly than channels. If plotted versus time, this injected volume fits a power relationship, according to the saturation state of the blocks. In less than 34 minutes, storage is close to zero in the blocks and to 1.6 to 2 m3 in the channels. For closing times shorter than 1 hour, only 1% of the volume that flows in the channels is stored into the blocks. Depending on the water pressure and for a given delta t = 3000 minutes, the volume of water stored is controlled by the geometry of the joint network and of the aquifer boundaries. Such an experiment shows that the flow is concentrated in about 10% of the fractured network (channels). The water storage that takes place in the 90% remaining fractures (blocks) depends mainly on time during which pressure remains high into the 10% channels. The accurate modeling of such typical double-permeability media needs a careful study of the geometry of the channels whose narrowings modify the flow and induce dam effects that maintain a high pressure gradient with surrounding blocks.

Effects of the Danish saturated fat tax on the demand for meat and dairy products.

PubMed

Jensen, Jørgen Dejgaard; Smed, Sinne; Aarup, Lars; Nielsen, Erhard

2016-12-01

Taxation of unhealthy food is considered a regulation tool to improve diets. In 2011 Denmark introduced a tax on saturated fat in food products, the first country in the world to do so. The objective of the present paper is to investigate the effects of the tax on consumers' intake of saturated fat within three different types of food product group: minced beef, regular cream and sour cream. We use an augmented version of the Linearized Almost Ideal Demand System (LAIDS) functional form for econometric analysis, allowing for tax-induced structural breaks. Data originate from one of the largest retail chains in Denmark (Coop Danmark) and cover January 2010 to October 2012, with monthly records of sales volume, sales revenue and information about specific campaigns from 1293 stores. The Danish fat tax had an insignificant or small negative effect on the price for low- and medium-fat varieties, and led to a 13-16 % price increase for high-fat varieties of minced beef and cream products. The tax induced substitution effects, budget effects and preference change effects on consumption, yielding a total decrease of 4-6 % in the intake of saturated fat from minced beef and regular cream, and a negligible effect on the intake from sour cream. The Danish introduction of a tax on saturated fat in food in October 2011 had statistically significant effects on the sales of fat in minced beef and cream products, but the tax seems to have reduced the beyond-recommendation saturated fat intake to only a limited extent.

Poromechanics Parameters of Fluid-Saturated Chemically Active Fibrous Media Derived from a Micromechanical Approach.

PubMed

Misra, Anil; Parthasarathy, Ranganathan; Singh, Viraj; Spencer, Paulette

2013-01-01

The authors have derived macroscale poromechanics parameters for chemically active saturated fibrous media by combining microstructure-based homogenization with Hill's volume averaging. The stress-strain relationship of the dry fibrous media is first obtained by considering the fiber behavior. The constitutive relationships applicable to saturated media are then derived in the poromechanics framework using Hill's Lemmas. The advantage of this approach is that the resultant continuum model assumes a form suited to study porous materials, while retaining the effect of discrete fiber deformation. As a result, the model is able to predict the influence of microscale phenomena such as fiber buckling on the overall behavior, and in particular, on the poromechanics constants. The significance of the approach is demonstrated using the effect of drainage and fiber nonlinearity on monotonic compressive stress-strain behavior. The model predictions conform to the experimental observations for articular cartilage. The method can potentially be extended to other porous materials such as bone, clays, foams, and concrete.

The Lawn Hill annulus: An Ordovician meteorite impact into water-saturated dolomite

NASA Astrophysics Data System (ADS)

Darlington, Vicki; Blenkinsop, Tom; Dirks, Paul; Salisbury, Jess; Tomkins, Andrew

2016-12-01

The Lawn Hill Impact Structure (LHIS) is located 250 km N of Mt Isa in NW Queensland, Australia, and is marked by a highly deformed dolomite annulus with an outer diameter of 18 km, overlying low metamorphic grade siltstone, sandstone, and shale, along the NE margin of the Georgina Basin. This study provides detailed field observations from sections of the Lawn Hill annulus and adjacent areas that demonstrate a clear link between the deformation of the dolomite and the Lawn Hill impact. 40Ar-39Ar dating of impact-related melt particles provides a time of impact in the Ordovician (472 ± 8 Ma) when the Georgina Basin was an active depocenter. The timing and stratigraphic thickness of the dolomite sequence in the annulus suggest that there was possibly up to 300 m of additional sedimentary rocks on top of the currently exposed Thorntonia Limestone at the time of impact. The exposed annulus is remarkably well preserved, with preservation attributed to postimpact sedimentation. The LHIS has an atypical crater morphology with no central uplift. The heterogeneous target materials at Lawn Hill were probably low-strength, porous, and water-saturated, with all three properties affecting the crater morphology. The water-saturated nature of the carbonate unit at the time of impact is thought to have influenced the highly brecciated nature of the annulus, and restricted melt production. The impact timing raises the possibility that the Lawn Hill structure may be a member of a group of impacts resulting from an asteroid breakup that occurred in the mid-Ordovician (470 ± 6 Ma).

Direct Numerical Simulations of Dynamic Drainage and Imbibition to Investigate Capillary Pressure-Saturation-Interfacial Area Relation

NASA Astrophysics Data System (ADS)

Konangi, S.; Palakurthi, N. K.; Karadimitriou, N.; Comer, K.; Ghia, U.

2017-12-01

We present results of pore-scale direct numerical simulations (DNS) of drainage and imbibition in a quasi-two-dimensional (40µm thickness) porous medium with a randomly distributed packing of cylindrical obstructions. The Navier-Stokes (NS) equations are solved in the pore space on an Eulerian mesh using the open-source finite-volume computational fluid dynamics (CFD) code, OpenFOAM. The Volume-of-Fluid (VOF) method is employed to track the evolution of the fluid-fluid interface; a static contact angle is used to account for wall adhesion. From the DNS data, we focus on the macroscopic capillary pressure-saturation (Pc-Sw) relation, which is known to be hysteretic, i.e., this relation is flow process (such as drainage, imbibition and scanning curves) and history dependent. In order to overcome the problem of hysteresis, extended theories of multiphase flow hypothesized that the inclusion of specific interfacial area as a state variable will result in a unique relation between capillary pressure, saturation and interfacial area (Pc-Sw-awn). We study the role of specific interfacial area on hysteresis in the macroscopic Pc-Sw relation under non-equilibrium (dynamic) conditions. Under dynamic conditions, capillary pressure depends on the rate of change of the wetting phase saturation, and the dynamic Pc-Sw relation includes the changes caused by viscous effects. Simulations of drainage and imbibition are performed for two capillary numbers by controlling the flow rate of the non-wetting (polydimenthlysiloxane oil) and wetting (water) fluids. From these simulations, the Pc-Sw curves will be estimated; the Pc-S-awn surface will be constructed to determine whether the data points from drainage and imbibition processes fall on a unique surface under transient conditions. Different macroscopic capillary pressure definitions based on phase-averaged pressures and interfacial area will be evaluated. Understanding macroscopic capillary pressure definitions and the uniqueness of the Pc-S- awn relation is step towards complete description of two-phase flow at the Darcy scale.

Mannitol Improves Brain Tissue Oxygenation in a Model of Diffuse Traumatic Brain Injury.

PubMed

Schilte, Clotilde; Bouzat, Pierre; Millet, Anne; Boucheix, Perrine; Pernet-Gallay, Karin; Lemasson, Benjamin; Barbier, Emmanuel L; Payen, Jean-François

2015-10-01

Based on evidence supporting a potential relation between posttraumatic brain hypoxia and microcirculatory derangements with cell edema, we investigated the effects of the antiedematous agent mannitol on brain tissue oxygenation in a model of diffuse traumatic brain injury. Experimental study. Neurosciences and physiology laboratories. Adult male Wistar rats. Thirty minutes after diffuse traumatic brain injury (impact-acceleration model), rats were IV administered with either a saline solution (traumatic brain injury-saline group) or 20% mannitol (1 g/kg) (traumatic brain injury-mannitol group). Sham-saline and sham-mannitol groups received no insult. Two series of experiments were conducted 2 hours after traumatic brain injury (or equivalent) to investigate 1) the effect of mannitol on brain edema and oxygenation, using a multiparametric magnetic resonance-based approach (n = 10 rats per group) to measure the apparent diffusion coefficient, tissue oxygen saturation, mean transit time, and blood volume fraction in the cortex and caudoputamen; 2) the effect of mannitol on brain tissue PO2 and on venous oxygen saturation of the superior sagittal sinus (n = 5 rats per group); and 3) the cortical ultrastructural changes after treatment (n = 1 per group, taken from the first experiment). Compared with the sham-saline group, the traumatic brain injury-saline group had significantly lower tissue oxygen saturation, brain tissue PO2, and venous oxygen saturation of the superior sagittal sinus values concomitant with diffuse brain edema. These effects were associated with microcirculatory collapse due to astrocyte swelling. Treatment with mannitol after traumatic brain injury reversed all these effects. In the absence of traumatic brain injury, mannitol had no effect on brain oxygenation. Mean transit time and blood volume fraction were comparable between the four groups of rats. The development of posttraumatic brain edema can limit the oxygen utilization by brain tissue without evidence of brain ischemia. Our findings indicate that an antiedematous agent such as mannitol can improve brain tissue oxygenation, possibly by limiting astrocyte swelling and restoring capillary perfusion.

A new estimate of the volume and distribution of gas hydrate in the northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Majumdar, U.; Cook, A.

2016-12-01

In spite of the wealth of information gained over the last several decades about gas hydrate in the northern Gulf of Mexico, there is still considerable uncertainty about the distribution and volume of gas hydrate. In our assessment we build a dataset of basin-wide gas hydrate distribution and thickness, as appraised from publicly available petroleum industry well logs within the gas hydrate stability zone (HSZ), and subsequently develop a Monte Carlo to determine the volumetric estimate of gas hydrate using the dataset. We evaluate the presence of gas hydrate from electrical resistivity well logs, and categorized possible reservoir type (either sand or clay) based on the gamma ray response and resistivity curve characteristics. Out of the 798 wells with resistivity well log data within the HSZ we analyzed, we found evidence of gas hydrate in 124 wells. In this research we present a new stochastic estimate of the gas hydrate volume in the northern Gulf of Mexico guided by our well log dataset. For our Monte Carlo simulation, we divided our assessment area of 200,000 km2 into 1 km2 grid cells. Our volume assessment model incorporates variables unique to our well log dataset such as the likelihood of gas hydrate occurrence, fraction of the HSZ occupied by gas hydrate, reservoir type, and gas hydrate saturation depending on the reservoir, in each grid cell, in addition to other basic variables such as HSZ thickness and porosity. Preliminary results from our model suggests that the total volume of gas at standard temperature and pressure in gas hydrate in the northern Gulf of Mexico is in the range of 430 trillion cubic feet (TCF) to 730 TCF, with a mean volume of 585 TCF. While the reservoir distribution from our well log dataset found gas hydrate in sand reservoirs in 30 wells out of the 124 wells with evidence of gas hydrate ( 24%), we find sand reservoirs contain over half of the total volume of gas hydrate in the Gulf of Mexico, as a result of the relatively high gas hydrate saturation in sand.

The DC dielectric breakdown strength of magnetic fluids based on transformer oil

NASA Astrophysics Data System (ADS)

Kopčanský, Peter; Tomčo, Ladislav; Marton, Karol; Koneracká, Martina; Timko, Milan; Potočová, Ivana

2005-03-01

The DC dielectric breakdown strength of magnetic fluids based on transformer oil TECHNOL US 4000, with different saturation magnetizations, was investigated in various orientations of external magnetic field. It was shown that the dielectric breakdown strength in H∣∣ E is strongly influenced by the aggregation effects. As a boundary volume concentration of magnetic particles, below which the magnetic fluids have better dielectric properties than pure transformer oil, the volume concentration Φ=0.01 was found. Thus magnetic fluids with Φ<0.01 are suitable for the use as a high-voltage insulation.

Antenna-Coupled Superconducting Tunnel Junctions with Single-Electron Transistor Readout for Detection of Sub-mm Radiation

NASA Technical Reports Server (NTRS)

Stevenson, T. R.; Hsieh, W.-T.; Li, M. J.; Stahle, C. M.; Wollack, E. J.; Schoelkopf, R. J.; Teufel, J.; Krebs, Carolyn (Technical Monitor)

2002-01-01

Antenna-coupled superconducting tunnel junction detectors have the potential for photon-counting sensitivity at sub-mm wavelengths. The device consists of an antenna structure to couple radiation into a small superconducting volume and cause quasiparticle excitations, and a single-electron transistor to measure currents through tunnel junction contacts to the absorber volume. We will describe optimization of device parameters, and recent results on fabrication techniques for producing devices with high yield for detector arrays. We will also present modeling of expected saturation power levels, antenna coupling, and rf multiplexing schemes.

HAMS (Hypoxia, Monitoring, and Mitigation System) II Quarterly Progress Report (Technical and Financial)

DTIC Science & Technology

2015-04-10

Peripheral Interface SpO2 Arterial Oxygen Saturation Measured via Pulse - Oximeter SRS Software Requirements Specification SV Stroke Volume SVR Systemic...viewer ....................................................................................................... 9 Figure 3: Pulse OX custom module...analysis approaches will be gathered. Sensors which detect SpO2, pulse / pulse rate, ECG, and skin temperature will be researched and evaluated for

RefMoB, a Reflectivity Feature Model-Based Automated Method for Measuring Four Outer Retinal Hyperreflective Bands in Optical Coherence Tomography

PubMed Central

Ross, Douglas H.; Clark, Mark E.; Godara, Pooja; Huisingh, Carrie; McGwin, Gerald; Owsley, Cynthia; Litts, Katie M.; Spaide, Richard F.; Sloan, Kenneth R.; Curcio, Christine A.

2015-01-01

Purpose. To validate a model-driven method (RefMoB) of automatically describing the four outer retinal hyperreflective bands revealed by spectral-domain optical coherence tomography (SDOCT), for comparison with histology of normal macula; to report thickness and position of bands, particularly band 2 (ellipsoid zone [EZ], commonly called IS/OS). Methods. Foveal and superior perifoveal scans of seven SDOCT volumes of five individuals aged 28 to 69 years with healthy maculas were used (seven eyes for validation, five eyes for measurement). RefMoB determines band thickness and position by a multistage procedure that models reflectivities as a summation of Gaussians. Band thickness and positions were compared with those obtained by manual evaluators for the same scans, and compared with an independent published histological dataset. Results. Agreement among manual evaluators was moderate. Relative to manual evaluation, RefMoB reported reduced thickness and vertical shifts in band positions in a band-specific manner for both simulated and empirical data. In foveal and perifoveal scans, band 1 was thick relative to the anatomical external limiting membrane, band 2 aligned with the outer one-third of the anatomical IS ellipsoid, and band 3 (IZ, interdigitation of retinal pigment epithelium and photoreceptors) was cleanly delineated. Conclusions. RefMoB is suitable for automatic description of the location and thickness of the four outer retinal hyperreflective bands. Initial results suggest that band 2 aligns with the outer ellipsoid, thus supporting its recent designation as EZ. Automated and objective delineation of band 3 will help investigations of structural biomarkers of dark-adaptation changes in aging. PMID:26132776

Development of an MRI biomarker sensitive to tetrameric visual arrestin 1 and its reduction via light-evoked translocation in vivo.

PubMed

Berkowitz, Bruce A; Gorgis, Jawan; Patel, Ankit; Baameur, Faiza; Gurevich, Vsevolod V; Craft, Cheryl M; Kefalov, Vladimir J; Roberts, Robin

2015-02-01

Rod tetrameric arrestin 1 (tet-ARR1), stored in the outer nuclear layer/inner segments in the dark, modulates photoreceptor synaptic activity; light exposure stimulates a reduction via translocation to the outer segments for terminating G-protein coupled phototransduction signaling. Here, we test the hypothesis that intraretinal spin-lattice relaxation rate in the rotating frame (1/T1ρ), an endogenous MRI contrast mechanism, has high potential for evaluating rod tet-ARR1 and its reduction via translocation. Dark- and light-exposed mice (null for the ARR1 gene, overexpressing ARR1, diabetic, or wild type with or without treatment with Mn2+, a calcium channel probe) were studied using 1/T1ρ MRI. Immunohistochemistry and single-cell recordings of the retinas were also performed. In wild-type mice with or without treatment with Mn2+, 1/T1ρ of avascular outer retina (64% to 72% depth) was significantly (P < 0.05) greater in the dark than in the light; a significant (P < 0.05) but opposite pattern was noted in the inner retina (<50% depth). Light-evoked outer retina Δ1/T1ρ was absent in ARR1-null mice and supernormal in overexpressing mice. In diabetic mice, the outer retinal Δ1/T1ρ pattern suggested normal dark-to-light tet-ARR1 translocation and chromophore content, conclusions confirmed ex vivo. Light-stimulated Δ1/T1ρ in inner retina was linked to changes in blood volume. Our data support 1/T1ρ MRI for noninvasively assessing rod tet-ARR1 and its reduction via protein translocation, which can be combined with other metrics of retinal function in vivo. © FASEB.

Guidance and navigation requirements for unmanned flyby and swingby missions to the outer planets. Volume 4: High thrust mission, part 2, phase C

NASA Technical Reports Server (NTRS)

1971-01-01

The guidance and navigation requirements for a set of impulsive thrust missions involving one or more outer planets or comets. Specific missions considered include two Jupiter entry missions of 800 and 1200 day duration, two multiple swingby missions with the sequences Jupiter-Uranus-Neptune and Jupiter-Saturn-Pluto, and two comets rendezvous missions involving the short period comets P/Tempel 2 and P/Tuttle-Giacobini-Kresak. Results show the relative utility of onboard and Earth-based DSN navigation. The effects of parametric variations in navigation accuracy, measurement rate, and miscellaneous constraints are determined. The utility of a TV type onboard navigation sensor - sighting on planetary satellites and comets - is examined. Velocity corrections required for the nominal and parametrically varied cases are tabulated.

An experimental investigation of the angular scattering and backscattering behaviors of the simulated clouds of the outer planets

NASA Technical Reports Server (NTRS)

Sassen, K.

1984-01-01

A cryogenic, 50 liter volume Planetary Cloud Simulation Chamber has been constructed to permit the laboratory study of the cloud compositions which are likely to be found in the atmospheres of the outer planets. On the basis of available data, clouds composed of water ice, carbon dioxide, and liquid and solid ammonia and methane, both pure and in various mixtures, have been generated. Cloud microphysical observations have been permitted through the use of a cloud particle slide injector and photomicrography. Viewports in the lower chamber have enabled the collection of cloud backscattering data using 633 and 838 nm laser light, including linear depolarization ratios and complete Stokes parameterization. The considerable technological difficulties associated with the collection of angular scattering patterns within the chamber, however, could not be completely overcome.

Investigation of a tubular dual-stator flux-switching permanent-magnet linear generator for free-piston energy converter

NASA Astrophysics Data System (ADS)

Sui, Yi; Zheng, Ping; Tong, Chengde; Yu, Bin; Zhu, Shaohong; Zhu, Jianguo

2015-05-01

This paper describes a tubular dual-stator flux-switching permanent-magnet (PM) linear generator for free-piston energy converter. The operating principle, topology, and design considerations of the machine are investigated. Combining the motion characteristic of free-piston Stirling engine, a tubular dual-stator PM linear generator is designed by finite element method. Some major structural parameters, such as the outer and inner radii of the mover, PM thickness, mover tooth width, tooth width of the outer and inner stators, etc., are optimized to improve the machine performances like thrust capability and power density. In comparison with conventional single-stator PM machines like moving-magnet linear machine and flux-switching linear machine, the proposed dual-stator flux-switching PM machine shows advantages in higher mass power density, higher volume power density, and lighter mover.

Combined effects of suction/injection and wall surface curvature on natural convection flow in a vertical micro-porous annulus

NASA Astrophysics Data System (ADS)

Jha, B. K.; Aina, B.; Muhammad, S. A.

2015-03-01

This study investigates analytically the hydrodynamic and thermal behaviour of a fully developed natural convection flow in a vertical micro-porous-annulus (MPA) taking into account the velocity slip and temperature jump at the outer surface of inner porous cylinder and inner surface of outer porous cylinder. A closed — form solution is presented for velocity, temperature, volume flow rate, skin friction and rate of heat transfer expressed as a Nusselt number. The influence of each governing parameter on hydrodynamic and thermal behaviour is discussed with the aid of graphs. During the course of investigation, it is found that as suction/injection on the cylinder walls increases, the fluid velocity and temperature is enhanced. In addition, it is observed that wall surface curvature has a significant effect on flow and thermal characteristics.

Sorption Modeling of Strontium, Plutonium, Uranium and Neptunium Adsorption on Monosodium Titanate

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

Fondeur, F.F.

2003-10-30

We examined the ability of various equilibrium isotherms to replicate the available data for the adsorption of strontium (Sr), plutonium (Pu), uranium (U) and neptunium (Np) on monosodium titanate (MST) during the treatment of simulated and actual Savannah River Site high-level waste. The analysis considered 29 isotherm models from the literature. As part of this study, we developed a general method for selecting the best isotherm models. The selection criteria for rating the isotherms considered the relative error in predicting the experimental data, the complexity of the mathematical expressions, the thermodynamic validity of the expressions, and statistical significance for themore » expressions. The Fowler Guggenheim-Jovanovic Freundlich (FG-JF), the Fowler Guggenheim-Langmuir Freundlich (FG-LF) and the Dubinin-Astashov (DA) models each reliably predicted the actinide and strontium adsorption on MST. The first two models describe the adsorption process by single layer formation and later al interactions between adsorbed sorbates while the Dubinin-Astashov model assumes volume filling of micropores (by osmotic pressure difference). These two mechanisms include mutually exclusive assumptions. However, we can not determine which model best represents the various adsorption mechanisms on MST. Based on our analysis, the DA model predicted the data well. The DA model assumes that an initial sorption layer forms after which networking begins in the pore spaces, filling the volume by a second mechanism. If this mechanism occurs in MST, as the experimental data suggests, then we expect all the empty and closed spaces of MST to contain actinides and strontium when saturated. Prior microstructure analyses determined that the MST surface is best described as heterogeneous (i.e., a semi-crystalline outer layer on an amorphous core) or composite material for adsorption. Therefore, we expect the empty spaces (of nanometer size) between the crystalline units in the fibrous material to provide sorption area for the actinides and strontium. Since each of the three models work reliably, we recommend use of the computationally simplest model as the primary tool until future work can differentiate between the two mechanisms. The Dubinin-Astashov model possesses a simpler mathematical form with fewer parameters and operations.« less

Multicenter reliability of semiautomatic retinal layer segmentation using OCT

PubMed Central

Oberwahrenbrock, Timm; Traber, Ghislaine L.; Lukas, Sebastian; Gabilondo, Iñigo; Nolan, Rachel; Songster, Christopher; Balk, Lisanne; Petzold, Axel; Paul, Friedemann; Villoslada, Pablo; Brandt, Alexander U.; Green, Ari J.

2018-01-01

Objective To evaluate the inter-rater reliability of semiautomated segmentation of spectral domain optical coherence tomography (OCT) macular volume scans. Methods Macular OCT volume scans of left eyes from 17 subjects (8 patients with MS and 9 healthy controls) were automatically segmented by Heidelberg Eye Explorer (v1.9.3.0) beta-software (Spectralis Viewing Module v6.0.0.7), followed by manual correction by 5 experienced operators from 5 different academic centers. The mean thicknesses within a 6-mm area around the fovea were computed for the retinal nerve fiber layer, ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer, outer plexiform layer (OPL), and outer nuclear layer (ONL). Intraclass correlation coefficients (ICCs) were calculated for mean layer thickness values. Spatial distribution of ICC values for the segmented volume scans was investigated using heat maps. Results Agreement between raters was good (ICC > 0.84) for all retinal layers, particularly inner retinal layers showed excellent agreement across raters (ICC > 0.96). Spatial distribution of ICC showed highest values in the perimacular area, whereas the ICCs were poorer for the foveola and the more peripheral macular area. The automated segmentation of the OPL and ONL required the most correction and showed the least agreement, whereas differences were less prominent for the remaining layers. Conclusions Automated segmentation with manual correction of macular OCT scans is highly reliable when performed by experienced raters and can thus be applied in multicenter settings. Reliability can be improved by restricting analysis to the perimacular area and compound segmentation of GCL and IPL. PMID:29552598

Iron acquisition by Haemophilus influenzae.

PubMed Central

Pidcock, K A; Wooten, J A; Daley, B A; Stull, T L

1988-01-01

The mechanisms for acquisition of iron by Haemophilus influenzae and their role in pathogenesis are not known. Heme and nonheme sources of iron were evaluated for their effect on growth of type b and nontypable strains of H. influenzae in an iron-restricted, defined medium. All 13 strains acquired iron from heme, hemoglobin, hemoglobin-haptoglobin, and heme-hemopexin. Among nonheme sources of protein-bound iron, growth of H. influenzae was enhanced by partially saturated human transferrin but not by lactoferrin or ferritin. Purified ferrienterochelin and ferridesferrioxamine failed to provide iron to H. influenzae, and the supernatants of H. influenzae E1a grown in iron-restricted medium failed to enhance iron-restricted growth of siderophore-dependent strains of Escherichia coli, Salmonella typhimurium, and Arthrobacter terregens. Marked alterations in the profile of outer membrane proteins of H. influenzae were observed when the level of free iron was varied between 1 microM and 1 mM. Catechols were not detected in the supernatants of strain E1a; however, iron-related hydroxamate production was detected by two biochemical assays. We conclude that the sources of iron for H. influenzae are diverse. The significance of hydroxamate production and iron-related outer membrane proteins to H. influenzae iron acquisition is not yet clear. Images PMID:2964410

Air Force Journal of Logistics. Volume 35, Numbers 1 and 2. Spring/Summer 2011

DTIC Science & Technology

2011-01-01

be used for integration into two layers of the suit. The outer layer could self - heal if punctured and the inner layer could monitor vital signs and...nanoscale robotics , the possibility of another nanotechnology Holy Grail, self -assembly, comes closer to reality. Professor Carlo Montemagno, of the...exploitation. Genetics, robotics , information technology, and nanotechnology are truly transformative technologies with the potential to impact national

Validation of Digital Systems in Avionics and Flight Control Applications Handbook. Volume 1.

DTIC Science & Technology

1983-07-01

will also be available to Airways Facilities, Systems Research and Development Service, Air Traffic Control Service, and Flight Standards elements...2114, March 12-14, 1979. 3. Validation Methods Research for Fault-Tolerant Avionics and Control Systems-- *r Working Group Meeting II, NASA...command generation with the multiple methods becoming avail- able for closure of the outer control loop necessitates research on alternative integration

Remineralization of in vitro dental caries assessed with polarization-sensitive optical coherence tomography

NASA Astrophysics Data System (ADS)

Jones, Robert S.; Darling, Cynthia L.; Featherstone, John D. B.; Fried, Daniel

2006-01-01

Polarization-sensitive optical coherence tomography (PS-OCT) is potentially useful for imaging the nonsurgical remineralization of dental enamel. This study uses an all-fiber-based PS-OCT system operating at 1310 nm to image demineralized and fluoride-enhanced remineralized artificial lesions. PS-OCT images of lesions before and after remineralization are compared with the relative mineral loss ΔZ (%vol×µm), obtained from high resolution digital microradiography (DM), and chemical composition changes by infrared spectroscopy. Severe early artificial caries show a significant increase in perpendicular-axis integrated reflectivity after remineralization. After sectioning the samples, DM demonstrates that the lesions remineralized with new mineral and the lesion surface zone show significant restoration of mineral volume. PS-OCT and DM both do not show a major change in lesion depth. For less severe artificial caries, the perpendicular-axis image resolves the scattering and depolarization of an outer growth layer after remineralization. This outer layer has a mineral volume close to that of sound enamel, and spectroscopic analysis indicates that the layer is a highly crystalline phase of apatite, without carbonate substitutions that increase the solubility of sound enamel. This study determines that PS-OCT can image the effects of fluoride-enhanced remineralization of mild and severe early artificial in vitro caries.

Time Resolved Tomographic PIV Measurements of Rough-Wall Turbulent Channel Flow

NASA Astrophysics Data System (ADS)

Miorini, Rinaldo; Zhang, Cao; Katz, Joseph

2013-11-01

Time resolved tomographic PIV is used to study flow structures in the outer region of a rough-wall turbulent boundary layer, focusing on imprints of the roughness on the outer layer. Measurements are performed in a transparent channel installed in the JHU optically index matched facility. The roughness consists of pyramids with height, k = 0.46 mm, and wavelength, λ = 3.2 mm, satisfying h/k = 55 (h = 25.4 mm is the channel half-height), k + = 64 and Re = 40000. The TPIV setup consists of four high-speed cameras operating at 3 kHz, which view the sample volume through acrylic prisms. The flow field is illuminated by an Nd:YLF laser. Following enhancement, calibration, and reconstruction, 643 voxels interrogation volumes with 0.75 overlap provide 3D velocity fields with spacing of 0.5883 mm3. Formation and transport of near-wall 3D U-shaped vortex structures, with base in front of the pyramids, and quasi-streamwise legs extending between pyramid crest lines are evident from the data. Extended streamwise regions of high wall-normal vorticity appear ``latched'' to the roughness elements close to the wall, but are transported downstream at higher elevations. Also evident are traveling streamwise low velocity streaks, which cover many roughness elements. Sponsored by NSF CBET and ONR.

Automatic lumen and outer wall segmentation of the carotid artery using deformable three-dimensional models in MR angiography and vessel wall images.

PubMed

van 't Klooster, Ronald; de Koning, Patrick J H; Dehnavi, Reza Alizadeh; Tamsma, Jouke T; de Roos, Albert; Reiber, Johan H C; van der Geest, Rob J

2012-01-01

To develop and validate an automated segmentation technique for the detection of the lumen and outer wall boundaries in MR vessel wall studies of the common carotid artery. A new segmentation method was developed using a three-dimensional (3D) deformable vessel model requiring only one single user interaction by combining 3D MR angiography (MRA) and 2D vessel wall images. This vessel model is a 3D cylindrical Non-Uniform Rational B-Spline (NURBS) surface which can be deformed to fit the underlying image data. Image data of 45 subjects was used to validate the method by comparing manual and automatic segmentations. Vessel wall thickness and volume measurements obtained by both methods were compared. Substantial agreement was observed between manual and automatic segmentation; over 85% of the vessel wall contours were segmented successfully. The interclass correlation was 0.690 for the vessel wall thickness and 0.793 for the vessel wall volume. Compared with manual image analysis, the automated method demonstrated improved interobserver agreement and inter-scan reproducibility. Additionally, the proposed automated image analysis approach was substantially faster. This new automated method can reduce analysis time and enhance reproducibility of the quantification of vessel wall dimensions in clinical studies. Copyright © 2011 Wiley Periodicals, Inc.

Scallop-Inspired Shell Engineering of Microparticles for Stable and High Volumetric Capacity Battery Anodes.

PubMed

Zhang, Xinghao; Guo, Ruiying; Li, Xianglong; Zhi, Linjie

2018-06-01

Building stable and efficient electron and ion transport pathways are critically important for energy storage electrode materials and systems. Herein, a scallop-inspired shell engineering strategy is proposed and demonstrated to confine high volume change silicon microparticles toward the construction of stable and high volumetric capacity binder-free lithium battery anodes. As for each silicon microparticle, the methodology involves an inner sealed but adaptable overlapped graphene shell, and an outer open hollow shell consisting of interconnected reduced graphene oxide, mimicking the scallop structure. The inner closed shell enables simultaneous stabilization of the interfaces of silicon with both carbon and electrolyte, substantially facilitates efficient and rapid transport of both electrons and lithium ions from/to silicon, the outer open hollow shell creates stable and robust transport paths of both electrons and lithium ions throughout the electrode without any sophisticated additives. The resultant self-supported electrode has achieved stable cycling with rapidly increased coulombic efficiency in the early stage, superior rate capability, and remarkably high volumetric capacity upon a facile pressing process. The rational design and engineering of graphene shells of the silicon microparticles developed can provide guidance for the development of a wide range of other high capacity but large volume change electrochemically active materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Respiration in heterotrophic unicellular eukaryotic organisms.

PubMed

Fenchel, Tom

2014-08-01

Surface:volume quotient, mitochondrial volume fraction, and their distribution within cells were investigated and oxygen gradients within and outside cells were modelled. Cell surface increases allometrically with cell size. Mitochondrial volume fraction is invariant with cell size and constitutes about 10% and mitochondria are predominantly found close to the outer membrane. The results predict that for small and medium sized protozoa maximum respiration rates should be proportional to cell volume (scaling exponent ≈1) and access to intracellular O2 is not limiting except at very low ambient O2-tensions. Available data do not contradict this and some evidence supports this interpretation. Cell size is ultimately limited because an increasing fraction of the mitochondria becomes exposed to near anoxic conditions with increasing cell size. The fact that mitochondria cluster close to the cell surface and the allometric change in cell shape with increasing cell size alleviates the limitation of aerobic life at low ambient O2-tension and for large cell size. Copyright © 2014 Elsevier GmbH. All rights reserved.

The coordination of ploidy and cell size differs between cell layers in leaves.

PubMed

Katagiri, Yohei; Hasegawa, Junko; Fujikura, Ushio; Hoshino, Rina; Matsunaga, Sachihiro; Tsukaya, Hirokazu

2016-04-01

Growth and developmental processes are occasionally accompanied by multiple rounds of DNA replication, known as endoreduplication. Coordination between endoreduplication and cell size regulation often plays a crucial role in proper organogenesis and cell differentiation. Here, we report that the level of correlation between ploidy and cell volume is different in the outer and inner cell layers of leaves of Arabidopsis thaliana using a novel imaging technique. Although there is a well-known, strong correlation between ploidy and cell volume in pavement cells of the epidermis, this correlation was extremely weak in palisade mesophyll cells. Induction of epidermis cell identity based on the expression of the homeobox gene ATML1 in mesophyll cells enhanced the level of correlation between ploidy and cell volume to near that of wild-type epidermal cells. We therefore propose that the correlation between ploidy and cell volume is regulated by cell identity. © 2016. Published by The Company of Biologists Ltd.

Heterogeneous water oxidation: surface activity versus amorphization activation in cobalt phosphate catalysts.

PubMed

González-Flores, Diego; Sánchez, Irene; Zaharieva, Ivelina; Klingan, Katharina; Heidkamp, Jonathan; Chernev, Petko; Menezes, Prashanth W; Driess, Matthias; Dau, Holger; Montero, Mavis L

2015-02-16

Is water oxidation catalyzed at the surface or within the bulk volume of solid oxide materials? This question is addressed for cobalt phosphate catalysts deposited on inert electrodes, namely crystallites of pakhomovskyite (Co3(PO4)2⋅8 H2O, Pak) and phosphate-containing Co oxide (CoCat). X-ray spectroscopy reveals that oxidizing potentials transform the crystalline Pak slowly (5-8 h) but completely into the amorphous CoCat. Electrochemical analysis supports high-TOF surface activity in Pak, whereas its amorphization results in dominating volume activity of the thereby formed CoCat material. In the directly electrodeposited CoCat, volume catalysis prevails, but not at very low levels of the amorphous material, implying high-TOF catalysis at surface sites. A complete picture of heterogeneous water oxidation requires insight in catalysis at the electrolyte-exposed "outer surface", within a hydrated, amorphous volume phase, and modes and kinetics of restructuring upon operation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of Urea Permeability in Red Cells by Minimum Method

PubMed Central

Sha'afi, R. I.; Rich, G. T.; Mikulecky, D. C.; Solomon, A. K.

1970-01-01

A new method has been developed for measuring the permeability coefficient, ω, of small nonelectrolytes. The method depends upon a mathematical analysis of the time course of cell volume changes in the neighborhood of the minimum volume following addition of a permeating solute to an isosmolal buffer. Coefficients determined by the minimum volume method agree with those obtained using radioactive tracers. ω for urea in human red cells was found to decrease as the volume flow, Jv, into the cell increased. Such behavior is entirely unexpected for a single uniform rate-limiting barrier on the basis of the linear phenomenological equations derived from irreversible thermodynamics. However, the present findings are consonant with a complex membrane system consisting of a tight barrier on the outer face of the human red cell membrane and a somewhat less restrictive barrier behind it closer to the inner membrane face. A theoretical analysis of such a series model has been made which makes predictions consistent with the experimental findings. PMID:5435779

Universality of the Volume Bound in Slow-Roll Eternal Inflation

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

Dubovsky, Sergei; Senatore, Leonardo; Villadoro, Giovanni

2012-03-28

It has recently been shown that in single field slow-roll inflation the total volume cannot grow by a factor larger than e{sup S{sub dS}/2} without becoming infinite. The bound is saturated exactly at the phase transition to eternal inflation where the probability to produce infinite volume becomes non zero. We show that the bound holds sharply also in any space-time dimensions, when arbitrary higher-dimensional operators are included and in the multi-field inflationary case. The relation with the entropy of de Sitter and the universality of the bound strengthen the case for a deeper holographic interpretation. As a spin-off we providemore » the formalism to compute the probability distribution of the volume after inflation for generic multi-field models, which might help to address questions about the population of vacua of the landscape during slow-roll inflation.« less

Static current-voltage characteristics for radio-frequency induction discharge

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

Budyansky, A.; Zykov, A.

1995-12-31

The aim of this work was to obtain experimentally such characteristic of Radio-Frequency Induction Discharge (RFID) that can play the role of its current-voltage characteristic (CVC) and to explain the nature of current and voltage jumps arising in RF coils at exciting of discharge. Experiments were made in quartz 5.5, 11, 20 cm diam tubes with outer RF coil at pressures 10--100 mTorr, at frequency 13.56 MHz and discharge power to 500 W. In case of outer coil as analogue of discharge voltage it`s convenient to use the value of the RF voltage U{sub R}, induced around outer perimeter ofmore » discharge tube. It is evident that current and voltage jumps arising at exciting of discharge are due to low output resistance of standard generators and negative slope of initial part of CVC. Three sets of such dependencies for different pressures were obtained for each diameter of tubes. The influence of different metal electrodes placed into discharge volume on CVC`s shape has been studied also. Experimental results can explain the behavior of HFI discharge as a load of RF generator and give data for calculation of RF circuit.« less

High performance liquid chromatographic hydrocarbon group-type analyses of mid-distillates employing fuel-derived fractions as standards

NASA Technical Reports Server (NTRS)

Seng, G. T.; Otterson, D. A.

1983-01-01

Two high performance liquid chromatographic (HPLC) methods have been developed for the determination of saturates, olefins and aromatics in petroleum and shale derived mid-distillate fuels. In one method the fuel to be analyzed is reacted with sulfuric acid, to remove a substantial portion of the aromatics, which provides a reacted fuel fraction for use in group type quantitation. The second involves the removal of a substantial portion of the saturates fraction from the HPLC system to permit the determination of olefin concentrations as low as 0.3 volume percent, and to improve the accuracy and precision of olefins determinations. Each method was evaluated using model compound mixtures and real fuel samples.

Interpreting DNAPL saturations in a laboratory-scale injection using one- and two-dimensional modeling of GPR Data

USGS Publications Warehouse

Johnson, R.H.; Poeter, E.P.

2005-01-01

Ground-penetrating radar (GPR) is used to track a dense non-aqueous phase liquid (DNAPL) injection in a laboratory sand tank. Before modeling, the GPR data provide a qualitative image of DNAPL saturation and movement. One-dimensional (1D) GPR modeling provides a quantitative interpretation of DNAPL volume within a given thickness during and after the injection. DNAPL saturation in sublayers of a specified thickness could not be quantified because calibration of the 1D GPR model is nonunique when both permittivity and depth of multiple layers are unknown. One-dimensional GPR modeling of the sand tank indicates geometric interferences in a small portion of the tank. These influences are removed from the interpretation using an alternate matching target. Two-dimensional (2D) GPR modeling provides a qualitative interpretation of the DNAPL distribution through pattern matching and tests for possible 2D influences that are not accounted for in the 1D GPR modeling. Accurate quantitative interpretation of DNAPL volumes using GPR modeling requires (1) identification of a suitable target that produces a strong reflection and is not subject to any geometric interference; (2) knowledge of the exact depth of that target; and (3) use of two-way radar-wave travel times through the medium to the target to determine the permittivity of the intervening material, which eliminates reliance on signal amplitude. With geologic conditions that are suitable for GPR surveys (i.e., shallow depths, low electrical conductivities, and a known reflective target), the procedures in this laboratory study can be adapted to a field site to delineate shallow DNAPL source zones.

Novel Assessment of Interstitial Lung Disease Using the "Computer-Aided Lung Informatics for Pathology Evaluation and Rating" (CALIPER) Software System in Idiopathic Inflammatory Myopathies.

PubMed

Ungprasert, Patompong; Wilton, Katelynn M; Ernste, Floranne C; Kalra, Sanjay; Crowson, Cynthia S; Rajagopalan, Srinivasan; Bartholmai, Brian J

2017-10-01

To evaluate the correlation between measurements from quantitative thoracic high-resolution CT (HRCT) analysis with "Computer-Aided Lung Informatics for Pathology Evaluation and Rating" (CALIPER) software and measurements from pulmonary function tests (PFTs) in patients with idiopathic inflammatory myopathies (IIM)-associated interstitial lung disease (ILD). A cohort of patients with IIM-associated ILD seen at Mayo Clinic was identified from medical record review. Retrospective analysis of HRCT data and PFTs at baseline and 1 year was performed. The abnormalities in HRCT were quantified using CALIPER software. A total of 110 patients were identified. At baseline, total interstitial abnormalities as measured by CALIPER, both by absolute volume and by percentage of total lung volume, had a significant negative correlation with diffusing capacity for carbon monoxide (DLCO), total lung capacity (TLC), and oxygen saturation. Analysis by subtype of interstitial abnormality revealed significant negative correlations between ground glass opacities (GGO) and reticular density (RD) with DLCO and TLC. At one year, changes of total interstitial abnormalities compared with baseline had a significant negative correlation with changes of TLC and oxygen saturation. A negative correlation between changes of total interstitial abnormalities and DLCO was also observed, but it was not statistically significant. Analysis by subtype of interstitial abnormality revealed negative correlations between changes of GGO and RD and changes of DLCO, TLC, and oxygen saturation, but most of the correlations did not achieve statistical significance. CALIPER measurements correlate well with functional measurements in patients with IIM-associated ILD.

A subjective evaluation of a drinking system for saturation divers.

PubMed

Hope, Arvid; Brekken, Rudolf

2010-03-01

Studies have shown that divers may lose large volumes of body fluids in hot water suit (HWS) dives lasting for four hours or longer, and that this dehydration is mainly caused by sweating. Body fluid balance may be impaired and the diver's alertness and power of judgement could be influenced by such imbalance. The main objective of the present study was to obtain a subjective judgement of a drinking system for divers (DSFD) and to obtain information related to body fluid loss during long saturation lock-out dives. Via a suction pipe imbedded in the microphone unit in the oronasal mask, the DSFD makes it possible for the diver to drink while in the water. Ten divers tested the drinking system during 12 saturation lock-out dives lasting on average for 5.5 h. A questionnaire was answered after each dive. The divers drank 21 times (range 5-30 times) during the dives, and the average drinking volume was 1.4 litre (range 1.0-1.5 litre) but only drank 0.04 litre (range 0-0.3 litre) in the bell after diving. The system was easy to operate and preparation and clothing did not cause any delay. The suction pipe did not intrude and the microphone performed excellently. The work in water was not hindered by DSFD and all divers were very satisfied with the drinking system. It was obvious that the need for fluid intake after a dive with DSFD was markedly reduced; another good indication of maintained body fluid balance.

Process scale-up considerations for non-thermal atmospheric-pressure plasma synthesis of nanoparticles by homogenous nucleation

NASA Astrophysics Data System (ADS)

Cole, Jonathan; Zhang, Yao; Liu, Tianqi; Liu, Chang-jun; Mohan Sankaran, R.

2017-08-01

Scale-up of non-thermal atmospheric-pressure plasma reactors for the synthesis of nanoparticles by homogeneous nucleation is challenging because the active volume is typically reduced to facilitate gas breakdown, enhance discharge stability, and limit particle size and agglomeration, but thus limits throughput. Here, we introduce a dielectric barrier discharge reactor consisting of a coaxial electrode geometry for nanoparticle production that enables a simple scale-up strategy whereby increasing the outer and inner electrode diameters, the plasma volume is increased approximately linearly, while maintaining a sufficiently small electrode gap to maintain the electric field strength. We show with two test reactors that for a given residence time, the nanoparticle production rate increases linearly with volume over a range of precursor concentrations, while having minimal effect on the shape of the particle size distribution. However, our study also reveals that increasing the total gas flow rate in a smaller volume reactor leads to an enhancement of precursor conversion and a comparable production rate to a larger volume reactor. These results suggest that scale-up requires better understanding of the influence of reactor geometry on particle growth dynamics and may not always be a simple function of reactor volume.

High air volume to low liquid volume aerosol collector

DOEpatents

Masquelier, Donald A.; Milanovich, Fred P.; Willeke, Klaus

2003-01-01

A high air volume to low liquid volume aerosol collector. A high volume flow of aerosol particles is drawn into an annular, centripetal slot in a collector which directs the aerosol flow into a small volume of liquid pool contained is a lower center section of the collector. The annular jet of air impinges into the liquid, imbedding initially airborne particles in the liquid. The liquid in the pool continuously circulates in the lower section of the collector by moving to the center line, then upwardly, and through assistance by a rotating deflector plate passes back into the liquid at the outer area adjacent the impinging air jet which passes upwardly through the liquid pool and through a hollow center of the collector, and is discharged via a side outlet opening. Any liquid droplets escaping with the effluent air are captured by a rotating mist eliminator and moved back toward the liquid pool. The collector includes a sensor assembly for determining, controlling, and maintaining the level of the liquid pool, and includes a lower centrally located valve assembly connected to a liquid reservoir and to an analyzer for analyzing the particles which are impinged into the liquid pool.

Vapor Saturation as The Cause of Volcanic Eruptions at the Lassen Volcanic Center, California, as Inferred from Crystallization Pressures and Temperatures

NASA Astrophysics Data System (ADS)

De Los Reyes, A. M. A.; Putirka, K. D.; Clynne, M. A.; Scruggs, M. A.

2015-12-01

The last three silicic eruptions at the Lassen Volcanic Center occurred at Lassen Peak (27 ka and 1915-17) and Chaos Crags (1103 yrs BP). Klemetti and Clynne (2014) showed that felsic eruptions at Lassen reflect remobilization of resident rhyodacitic crystal mush by intrusion of mafic magma. To better understand the rejuvenation and eruption triggering process, we calculate crystallization temperatures and pressures from clinopyroxene-liquid equilibria on mafic enclaves that provide our closest approach to the composition of mafic magmas delivered to the shallow system. Our goal is to examine whether and to what extent cooling and crystallization occur after recharge, which bears on whether recharge, mixing, or partial crystallization (and consequent vapor saturation) provide the trigger for eruption. We use results from the cpx-liq barometer (1.7 kbar) as input to calculate T for other phases (plagioclase, olivine and amphibole) found in mafic enclave samples. Cpx crystallizes at 1100-1150 oC and olivine precipitates at similar to slightly higher temperatures. Cpx and ol are followed by plagioclase (1000-1050 oC), amphibole (875-1000 oC), and Fe-Ti oxides (1030-1050 oC). These temperatures indicate that recharge magmas are incompletely crystallized as they enter the shallow reservoir of cooler (~725-750 oC, Quinn et al., 2013) felsic crystal mush, and that significant cooling of the mafic magma occurs during mixing and prior to eruption. Such cooling intervals indicate that recharge is not the proximal cause of eruption, but rather that vapor saturation, following a period of mixing and cooling, leads to increased magma overpressure that causes eruption. Interestingly, the Lassen Peak 27 ka volcanics (at 2.09 km3), have a greater volume than either of Chaos Crags (1.2 km3) and the 1915 (0.03 km3) eruption, but our results indicate that their thermal histories are similar. This suggests that while volumes of mafic recharge may control the degree of interaction with felsic crystal mush (e.g., Clynne, 1999), and eventually the volume of erupted magma, recharge volumes do not affect eruption triggering mechanisms. Clynne MA (1999) J. Petrol, 40: 105-132.Klemetti and Clynne, 2014, PLoS One (/12:e113157. doi10.1371/journal.pone0113157)Quinn et al., 2013, AGU Fall Annual Meeting V23C-2848

Sensitivity models and design protocol for partitioning tracer tests in alluvial aquifers

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

Jin, M.; Butler, G.W.; Jackson, R.E.

1997-11-01

Zones of dense, nonaqueous phase liquids (DNAPLs) are difficult to characterize as to their volume, composition, and spatial distribution using conventional ground-water extraction and soil-sampling methods. Such incompletely characterized sites have negative consequences for those responsible for their remedial design, e.g., the uncertainties in the optimal placement of ground-water extraction wells and in the duration of remediation. However, the recent use of the partitioning interwell tracer test (PITT) to characterize DNAPL zones at sites in New Mexico [unsaturated alluvium] and in Ohio, Texas, and Utah [saturated alluvium] demonstrates that the volume and spatial distribution of residual DNAPL can be determinedmore » with accuracy. The PITT involves injection of a suite of tracers which reversibly partition to different degrees between the DNAPL and the ground water or soil air resulting in the chromatographic separation of the tracer signals observed at the extraction well(s). The design of a PITT requires careful consideration of the hydrostratigraphic, hydraulic, and certain geochemical properties of the alluvium being tested. A three-dimensional, numerical model of a heterogeneous alluvial aquifer containing DNAPL has been developed for use with the UTCHEM simulator to demonstrate partitioning tracer testing and to address questions that are frequently raised in its application. The simulations include (1) the estimation of DNAPL volume for the simple case where only residual DNAPL is present in heterogeneous alluvium, (2) sensitivity studies to demonstrate the effect of increasingly low residual DNAPL saturation on the tracer signal, and (3) the effect of free-phase DNAPL on the estimation of the volume of DNAPL present. Furthermore, the potential interference of sedimentary organic carbon as a DNAPL surrogate on the tracer signal is considered and shown to be readily resolved by the careful choice of tracers.« less

Computation of resistive instabilities by matched asymptotic expansions

DOE PAGES

Glasser, A. H.; Wang, Z. R.; Park, J. -K.

2016-11-17

Here, we present a method for determining the linear resistive magnetohydrodynamic (MHD) stability of an axisymmetric toroidal plasma, based on the method of matched asymptotic expansions. The plasma is partitioned into a set of ideal MHD outer regions, connected through resistive MHD inner regions about singular layers where q = m/n, with m and n toroidal mode numbers, respectively, and q the safety factor. The outer regions satisfy the ideal MHD equations with zero-frequency, which are identical to the Euler-Lagrange equations for minimizing the potential energy delta W. The solutions to these equations go to infinity at the singular surfaces.more » The inner regions satisfy the equations of motion of resistive MHD with a finite eigenvalue, resolving the singularity. Both outer and inner regions are solved numerically by newly developed singular Galerkin methods, using specialized basis functions. These solutions are matched asymptotically, providing a complex dispersion relation which is solved for global eigenvalues and eigenfunctions in full toroidal geometry. The dispersion relation may have multiple complex unstable roots, which are found by advanced root-finding methods. These methods are much faster and more robust than the previous numerical methods. The new methods are applicable to more challenging high-pressure and strongly shaped plasma equilibria and generalizable to more realistic inner region dynamics. In the thermonuclear regime, where the outer and inner regions overlap, they are also much faster and more accurate than the straight-through methods, which treat the resistive MHD equations in the whole plasma volume.« less

Experimental and theoretical investigation of LNAPL movement in stratified media during soil remediation.

PubMed

Lashanizadegan, A; Ayatollahi, Sh; Kazemi, H

2007-07-01

The saturation distribution and clean up efficiency of light non-aqueous phase liquid (LNAPL) in the strata beneath the earth has been the subject of many studies. Better understanding of LNAPL infiltration into layered soil is important for the effective design of remediation strategies. The objective of this study was to simulate LNAPL movement in homogenous and stratified porous media using gravity assisted inert gas injection (GAIGI) process as a cleaning technique. We used homogeneous and layered sandpacked transparent models that allows for visual observation of LNAPL movement in order to study LNAPL redistribution in a layered porous medium. Pore volume, porosity, absolute permeability, connate water saturation, and oil saturation of the models were determined experimentally. Seasonal water table movement and contaminated zone were established and then, under GAIGI process, clean up efficiency was determined. The downward displacement of LNAPL by gas drive resulted in very high LNAPL clean up efficiency. Using the contaminant production history in the homogeneous model, the LNAPL relative permeability was calculated and the results were extended to layered media. The numerical multi-phase flow model in porous media was validated with regard to the experimental results. This model is able to adequately reproduce the experimental LNAPL saturation profile and clean up efficiency.

Micro-poromechanics model of fluid-saturated chemically active fibrous media.

PubMed

Misra, Anil; Parthasarathy, Ranganathan; Singh, Viraj; Spencer, Paulette

2015-02-01

We have developed a micromechanics based model for chemically active saturated fibrous media that incorporates fiber network microstructure, chemical potential driven fluid flow, and micro-poromechanics. The stress-strain relationship of the dry fibrous media is first obtained by considering the fiber behavior. The constitutive relationships applicable to saturated media are then derived in the poromechanics framework using Hill's volume averaging. The advantage of this approach is that the resultant continuum model accounts for the discrete nature of the individual fibers while retaining a form suitable for porous materials. As a result, the model is able to predict the influence of micro-scale phenomena, such as the fiber pre-strain caused by osmotic effects and evolution of fiber network structure with loading, on the overall behavior and in particular, on the poromechanics parameters. Additionally, the model can describe fluid-flow related rate-dependent behavior under confined and unconfined conditions and varying chemical environments. The significance of the approach is demonstrated by simulating unconfined drained monotonic uniaxial compression under different surrounding fluid bath molarity, and fluid-flow related creep and relaxation at different loading-levels and different surrounding fluid bath molarity. The model predictions conform to the experimental observations for saturated soft fibrous materials. The method can potentially be extended to other porous materials such as bone, clays, foams and concrete.

Confirmation of saturation equilibrium conditions in crater populations

NASA Technical Reports Server (NTRS)

Hartmann, William K.; Gaskell, Robert W.

1993-01-01

We have continued work on realistic numerical models of cratered surfaces, as first reported at last year's LPSC. We confirm the saturation equilibrium level with a new, independent test. One of us has developed a realistic computer simulation of a cratered surface. The model starts with a smooth surface or fractal topography, and adds primary craters according to the cumulative power law with exponent -1.83, as observed on lunar maria and Martian plains. Each crater has an ejecta blanket with the volume of the crater, feathering out to a distance of 4 crater radii. We use the model to test the levels of saturation equilibrium reached in naturally occurring systems, by increasing crater density and observing its dependence on various parameters. In particular, we have tested to see if these artificial systems reach the level found by Hartmann on heavily cratered planetary surfaces, hypothesized to be the natural saturation equilibrium level. This year's work gives the first results of a crater population that includes secondaries. Our model 'Gaskell-4' (September, 1992) includes primaries as described above, but also includes a secondary population, defined by exponent -4. We allowed the largest secondary from each primary to be 0.10 times the size of the primary. These parameters will be changed to test their effects in future models. The model gives realistic images of a cratered surface although it appears richer in secondaries than real surfaces are. The effect of running the model toward saturation gives interesting results for the diameter distribution. Our most heavily cratered surface had the input number of primary craters reach about 0.65 times the hypothesized saturation equilibrium, but the input number rises to more than 100 times that level for secondaries below 1.4 km in size.

Changes in the composition and properties of Ashalchinskoye bitumen-saturated sandstones when exposed to water vapor

NASA Astrophysics Data System (ADS)

Korolev, E.; Eskin, A.; Kolchugin, A.; Morozov, V.; Khramchenkov, M.; Gabdelvalieva, R.

2018-05-01

Ashalchinskoye bitumen deposit is an experimental platform for testing technology of high-viscosity oil extraction from reservoir rocks. Last time for enhanced of oil recovery in reservoir used pressurization a water vapor with a temperature of ∼ 180 ° C (SAGD technology). However, what happens in sandstone reservoir is little known. We did a study of the effects of water vapor on the structural components of bitumen saturated sandstone. In paper were studied the rock samples at base condition and after one week exposure by water vapour. The thermal analysis showed that steaming helps to removes light and middle oil fractions with a boiling point up to 360 ° C from oil saturated sandstones. Content of heavy oil fractions virtually unchanged. Studying the composition of water extractions of samples showed that the process of aquathermolysis of oil is accompanied by a lowering of the pH of the pore solution from 7.4 to 6.5 and rise content in several times of mobile cations Ca2+, Mg2+ and HCO3 -, SO4 2- anions. Follows from this that the thermal steam effect by bitumen saturated sandstones leads to partial oxidation of hydrocarbons with to form a carbon dioxide. The source of sulfate ions were oxidized pyrite aggregates. Due to the increasing acidity of condensed water, which fills the pore space of samples, pore fluid becomes aggressive to calcite and dolomite cement of bitumen saturated sandstones. As a result of the dissolution of carbonate cement the pore fluid enriched by calcium and magnesium cations. Clearly, that the process is accompanied by reduction of contact strength between fragments of minerals and rocks. Resulting part of compounds is separated from the outer side of samples and falls to bottom of water vapor container. Decreasing the amount of calcite and dolomite anions in samples in a steam-treated influence is confirmed by X-Ray analysis. X-Ray analysis data of study adscititious component of rocks showed that when influenced of water vapor to bitumen saturated sandstones there are the processes of transformation of clay minerals. Mixed-illite-montmorillonite phase is primarily exposed to changes. In this case we fix initial stage of the destruction of polycrystalline particles mixed-mineral. Reducing the size of clay minerals particles along the normal to the layers (L001) is the result from lower energy costs of delamination and disintegration the crystallites along this direction, in comparison with others. Thus, using of SAGD technology at exploitation of Ashalchinskoye bitumen saturated reservoir will be followed by acidification of the pore fluid, activation processes of dissolution calcite cement and transformation of mixed-layers clays minerals.

[Cardiorespiratory effects of the body position in premature newborns submitted to the increase of the gastric volume].

PubMed

Pádua, Gisley de; Martinez, Edson Zangiacomi; Brunherotti, Marisa Afonso de Andrade

2009-01-01

The increase of the gastric volume observed in the gavage feeding is likely to cause consequences to the premature newborn, modifying the respiratory indicators. To investigate the alterations in the cardiorespiratory system of premature newborns submitted to an increase of the gastric volume by gavage feeding, according to four different body positioning methods. The study is a randomized crossover trial using a sample of 16 newborns with gestational age from 31 to 34 weeks and birth weight less or equal to 2.500 g. The newborns were included in the study if they had from 7 to 10 days of life, feeding by orogastric tube, total volume of 150 mL/kg/day and absence of supplemental oxygen-therapy. A different positioning method was used at each gavage (all raised to 30 degrees), or say, right lateral, left lateral, prone and supine positions. The following response variables were considered: respiratory and cardiac frequencies, saturation of oxygen, drawing of intercostals, beating of nasal wing and grunting. These measures were collected in intervals of 2 minutes during 5 minutes after the gavage feeding, during whole period of the gavage feeding, and during 5 minutes before the gavage feeding. The mean gestational age was 32 weeks (standard deviation 1.3) and the mean weight of the newborns was 1.722 g (standard deviation 276.3). The newborns presented higher values of the mean respiratory frequency in supine and left lateral body positions. In the right lateral and prone positions, the newborns presented lower mean cardiac frequency. The mean oxygen saturation had the lowest values in the left lateral and supine positions. The right lateral and prone positions presented low frequencies of intercostals drawing, beating of nasal wing and grunting. Our results indicate that right lateral and prone positions have influence on the cardiorespiratory effect, where left lateral and supine are the positions who presented higher negative effect in the newborns submitted to the increase of the gastric volume.

Effect of Native Oxide Film on Commercial Magnesium Alloys Substrates and Carbonate Conversion Coating Growth and Corrosion Resistance

PubMed Central

Feliu, Sebastián; Samaniego, Alejandro; Bermudez, Elkin Alejandro; El-Hadad, Amir Abdelsami; Llorente, Irene; Galván, Juan Carlos

2014-01-01

Possible relations between the native oxide film formed spontaneously on the AZ31 and AZ61 magnesium alloy substrates with different surface finish, the chemistry of the outer surface of the conversion coatings that grows after their subsequent immersion on saturated aqueous NaHCO3 solution treatment and the enhancement of corrosion resistance have been studied. The significant increase in the amount of aluminum and carbonate compounds on the surface of the conversion coating formed on the AZ61 substrate in polished condition seems to improve the corrosion resistance in low chloride ion concentration solutions. In contrast, the conversion coatings formed on the AZ31 substrates in polished condition has little effect on their protective properties compared to the respective as-received surface. PMID:28788582

Effect of Native Oxide Film on Commercial Magnesium Alloys Substrates and Carbonate Conversion Coating Growth and Corrosion Resistance.

PubMed

Feliu, Sebastián; Samaniego, Alejandro; Bermudez, Elkin Alejandro; El-Hadad, Amir Abdelsami; Llorente, Irene; Galván, Juan Carlos

2014-03-28

Possible relations between the native oxide film formed spontaneously on the AZ31 and AZ61 magnesium alloy substrates with different surface finish, the chemistry of the outer surface of the conversion coatings that grows after their subsequent immersion on saturated aqueous NaHCO₃ solution treatment and the enhancement of corrosion resistance have been studied. The significant increase in the amount of aluminum and carbonate compounds on the surface of the conversion coating formed on the AZ61 substrate in polished condition seems to improve the corrosion resistance in low chloride ion concentration solutions. In contrast, the conversion coatings formed on the AZ31 substrates in polished condition has little effect on their protective properties compared to the respective as-received surface.

A versatile miniature bioreactor and its application to bioelectrochemistry studies.

PubMed

Kloke, A; Rubenwolf, S; Bücking, C; Gescher, J; Kerzenmacher, S; Zengerle, R; von Stetten, F

2010-08-15

Often, reproducible investigations on bio-microsystems essentially require a flexible but well-defined experimental setup, which in its features corresponds to a bioreactor. We therefore developed a miniature bioreactor with a volume in the range of a few millilitre that is assembled by alternate stacking of individual polycarbonate elements and silicone gaskets. All the necessary supply pipes are incorporated as bore holes or cavities within the individual elements. Their combination allows for a bioreactor assembly that is easily adaptable in size and functionality to experimental demands. It allows for controlling oxygen transfer as well as the monitoring of dissolved oxygen concentration and pH-value. The system provides access for media exchange or sterile sampling. A mass transfer coefficient for oxygen (k(L)a) of 4.3x10(-3) s(-1) at a flow rate of only 15 ml min(-1) and a mixing time of 1.5s at a flow rate of 11 ml min(-1) were observed for the modular bioreactor. Single reactor chambers can be interconnected via ion-conductive membranes to form a two-chamber test setup for investigations on electrochemical systems such as fuel cells or sensors. The versatile applicability of this modular and flexible bioreactor was demonstrated by recording a growth curve of Escherichia coli (including monitoring of pH and oxygen) saturation, and also as by two bioelectrochemical experiments. In the first electrochemical experiment the use of the bioreactor enabled a direct comparison of electrode materials for a laccase-catalyzed oxygen reduction electrode. In a second experiment, the bioreactor was utilized to characterize the influence of outer membrane cytochromes on the performance of Shewanella oneidensis in a microbial fuel cell. Copyright 2010 Elsevier B.V. All rights reserved.

Single-cell measurement of red blood cell oxygen affinity.

PubMed

Di Caprio, Giuseppe; Stokes, Chris; Higgins, John M; Schonbrun, Ethan

2015-08-11

Oxygen is transported throughout the body by hemoglobin (Hb) in red blood cells (RBCs). Although the oxygen affinity of blood is well-understood and routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of RBC volume and Hb concentration are taken millions of times per day by clinical hematology analyzers, and they are important factors in determining the health of the hematologic system. To better understand the variability and determinants of oxygen affinity on a cellular level, we have developed a system that quantifies the oxygen saturation, cell volume, and Hb concentration for individual RBCs in high throughput. We find that the variability in single-cell saturation peaks at an oxygen partial pressure of 2.9%, which corresponds to the maximum slope of the oxygen-Hb dissociation curve. In addition, single-cell oxygen affinity is positively correlated with Hb concentration but independent of osmolarity, which suggests variation in the Hb to 2,3-diphosphoglycerate (2-3 DPG) ratio on a cellular level. By quantifying the functional behavior of a cellular population, our system adds a dimension to blood cell analysis and other measurements of single-cell variability.

Single-cell measurement of red blood cell oxygen affinity

PubMed Central

Di Caprio, Giuseppe; Stokes, Chris; Higgins, John M.; Schonbrun, Ethan

2015-01-01

Oxygen is transported throughout the body by hemoglobin (Hb) in red blood cells (RBCs). Although the oxygen affinity of blood is well-understood and routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of RBC volume and Hb concentration are taken millions of times per day by clinical hematology analyzers, and they are important factors in determining the health of the hematologic system. To better understand the variability and determinants of oxygen affinity on a cellular level, we have developed a system that quantifies the oxygen saturation, cell volume, and Hb concentration for individual RBCs in high throughput. We find that the variability in single-cell saturation peaks at an oxygen partial pressure of 2.9%, which corresponds to the maximum slope of the oxygen–Hb dissociation curve. In addition, single-cell oxygen affinity is positively correlated with Hb concentration but independent of osmolarity, which suggests variation in the Hb to 2,3-diphosphoglycerate (2–3 DPG) ratio on a cellular level. By quantifying the functional behavior of a cellular population, our system adds a dimension to blood cell analysis and other measurements of single-cell variability. PMID:26216973

Hierarchical neural network model of the visual system determining figure/ground relation

NASA Astrophysics Data System (ADS)

Kikuchi, Masayuki

2017-07-01

One of the most important functions of the visual perception in the brain is figure/ground interpretation from input images. Figural region in 2D image corresponding to object in 3D space are distinguished from background region extended behind the object. Previously the author proposed a neural network model of figure/ground separation constructed on the standpoint that local geometric features such as curvatures and outer angles at corners are extracted and propagated along input contour in a single layer network (Kikuchi & Akashi, 2001). However, such a processing principle has the defect that signal propagation requires manyiterations despite the fact that actual visual system determines figure/ground relation within the short period (Zhou et al., 2000). In order to attain speed-up for determining figure/ground, this study incorporates hierarchical architecture into the previous model. This study confirmed the effect of the hierarchization as for the computation time by simulation. As the number of layers increased, the required computation time reduced. However, such speed-up effect was saturatedas the layers increased to some extent. This study attempted to explain this saturation effect by the notion of average distance between vertices in the area of complex network, and succeeded to mimic the saturation effect by computer simulation.

Chemical Reaction between Boric Acid and Phosphine Indicates Boric Acid as an Antidote for Aluminium Phosphide Poisoning

PubMed Central

Soltani, Motahareh; Shetab-Boushehri, Seyed F.; Shetab-Boushehri, Seyed V.

2016-01-01

Objectives: Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. Methods: This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Results: Activated charcoal significantly reduced the volume of released gas (P <0.01). Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01). A gaseous adduct was formed in the reaction between pure AlP and boric acid. Conclusion: These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning. PMID:27606109

Molar heat capacity at constant volume of 1,1-difluoroethane (R152a) and 1,1,1-trifluoroethane (R143a) from the triple-point temperature to 345 k at pressure to 35 MPa

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

Magee, J.W.

1998-09-01

Molar heat capacities at constant volume (C{sub v}) of 1,1-difluoroethane (R152a) and 1,1,1-trifluoroethane (R143a) have been measured with an adiabatic calorimeter. Temperatures ranged from their triple points to 345 K, and pressures up to 35 MPa. Measurements were conducted on the liquid in equilibrium with its vapor and on compressed liquid samples. The samples were of high purity, verified by chemical analysis of each fluid. For the samples, calorimetric results were obtained for two-phase (C{sub v}{sup (2)}), saturated-liquid (C{sub {sigma}} or C{sub x}{prime}), and single-phase (C{sub v}) molar heat capacities. The C{sub {sigma}} data were used to estimate vapor pressuresmore » for values less than 105 kPa by applying a thermodynamic relationship between the saturated liquid heat capacity and the temperature derivatives of the vapor pressure. The triple-point temperature and the enthalpy of fusion were also measured for each substance. The principal sources of uncertainty are the temperature rise measurement and the change-of-volume work adjustment. The expanded relative uncertainty (with a coverage factor k = 2 and thus a two-standard deviation estimate) for C{sub v} is estimated to be 0.7%, for C{sub v}{sup (2)} it is 0.5%, and for C{sub {sigma}} it is 0.7%.« less

Numerical Simulation of nZVI at the Field Scale

NASA Astrophysics Data System (ADS)

Chowdhury, A. I.; Krol, M.; Sleep, B. E.; O'Carroll, D. M.

2014-12-01

Nano-scale zero valent iron (nZVI) has been used at a number of contaminated sites over the last decade. At most of these sites, significant decreases in contaminant concentrations have resulted from the application of nZVI. However, limited work has been completed investigating nZVI mobility at the field-scale. In this study a three dimensional, three phase, finite difference numerical simulator (CompSim) was used to simulate nZVI and polymer transport in a variably saturated site. The model was able to accurately predict the field observed head data without parameter fitting. In addition, the numerical simulator estimated the amount of nZVI delivered to the saturated and unsaturated zones as well as the phase of nZVI (i.e., attached or aqueous phase). The simulation results showed that the injected slurry migrated radially outward from the injection well, and therefore nZVI transport was governed by injection velocity as well as viscosity of the injected solution. A suite of sensitivity analyses was performed to investigate the impact of different injection scenarios (e.g. different volume and injection rate) on nZVI migration. Simulation results showed that injection of a higher volume of nZVI delivered more iron particles at a given distance; however, not necessarily to a greater distance proportionate to the increase in volume. This study suggests that on-site synthesized nZVI particles are mobile in the subsurface and the numerical simulator can be a valuable tool for optimum design of nZVI applications.

New International Skeleton Tables for the Thermodynamic Properties of Ordinary Water Substance

NASA Astrophysics Data System (ADS)

Sato, H.; Uematsu, M.; Watanabe, K.; Saul, A.; Wagner, W.

1988-10-01

The current knowledge of thermodynamic properties of ordinary water substance is summarized in a condensed form of a set of skeleton steam tables, where the most probable values with the reliabilities on specific volume and enthalpy are provided in the range of temperatures from 273 to 1073 K and pressures from 101.325 kPa to 1 GPa and at the saturation state from the triple point to the critical point. These tables have been accepted as the IAPS Skeleton Tables 1985 for the Thermodynamic Properties of Ordinary Water Substance(IST-85) by the International Association for the Properties of Steam(IAPS). The former International Skeleton Steam Tables, October 1963(IST-63), have been withdrawn by IAPS. About 17 000 experimental thermodynamic data were assessed and classified previously by Working Group 1 of IAPS. About 10 000 experimental data were collected and evaluated in detail and especially about 7000 specific-volume data among them were critically analyzed with respect to their errors using the statistical method originally developed at Keio University by the first three authors. As a result, specific-volume and enthalpy values with associated reliabilities were determined at 1455 grid points of 24 isotherms and 61 isobars in the single-fluid phase state and at 54 temperatures along the saturation curve. The background, analytical procedure, and reliability of IST-85 as well as the assessment of the existing experimental data and equations of state are also discussed in this paper.

Experimental verification of gain drop due to general ion recombination for a carbon-ion pencil beam

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

Tansho, Ryohei, E-mail: r-tansho@nirs.go.jp; Furukawa, Takuji; Hara, Yousuke

Purpose: Accurate dose measurement in radiotherapy is critically dependent on correction for gain drop, which is the difference of the measured current from the ideal saturation current due to general ion recombination. Although a correction method based on the Boag theory has been employed, the theory assumes that ionized charge density in an ionization chamber (IC) is spatially uniform throughout the irradiation volume. For particle pencil beam scanning, however, the charge density is not uniform, because the fluence distribution of a pencil beam is not uniform. The aim of this study was to verify the effect of the nonuniformity ofmore » ionized charge density on the gain drop due to general ion recombination. Methods: The authors measured the saturation curve, namely, the applied voltage versus measured current, using a large plane-parallel IC and 24-channel parallel-plate IC with concentric electrodes. To verify the effect of the nonuniform ionized charge density on the measured saturation curve, the authors calculated the saturation curve using a method which takes into account the nonuniform ionized charge density and compared it with the measured saturation curves. Results: Measurement values of the different saturation curves in the different channels of the concentric electrodes differed and were consistent with the calculated values. The saturation curves measured by the large plane-parallel IC were also consistent with the calculation results, including the estimation error of beam size and of setup misalignment. Although the impact of the nonuniform ionized charge density on the gain drop was clinically negligible with the conventional beam intensity, it was expected that the impact would increase with higher ionized charge density. Conclusions: For pencil beam scanning, the assumption of the conventional Boag theory is not valid. Furthermore, the nonuniform ionized charge density affects the prediction accuracy of gain drop when the ionized charge density is increased by a higher dose rate and/or lower beam size.« less

Epitaxial thin film growth in outer space

NASA Technical Reports Server (NTRS)

Ignatiev, Alex; Chu, C. W.

1988-01-01

A new concept for materials processing in space exploits the ultravacuum component of space for thin-film epitaxial growth. The unique LEO space environment is expected to yield 10-ftorr or better pressures, semiinfinite pumping speeds, and large ultravacuum volume (about 100 cu m) without walls. These space ultravacuum properties promise major improvement in the quality, unique nature, and throughput of epitaxially grown materials, including semiconductors, magnetic materials, and thin-film high-temperature superconductors.

46th Annual Gun and Missile Systems Conference and Exhibition. Volume 3 - Thursday

DTIC Science & Technology

2011-09-01

Grade Sensors Through Use of Accelerated Aging Principles Mr. Scott Gift 11657 Modeling of the Autofrettage Processes of a Gun Barrel Mr. Sudhir...Emissions Measured on the Outer Portion of a Composite Barrel Ms. Rushie Ghimire GUN & MISSILE SYSTEMS ADDITIONAL AUTHORS GUN & MISSILE SYSTEMS...Transportation – Loading – Gun Fire to Barrel Exit – After Barrel Exit • Passing: Fuze safety devices remain safe; safe for disposal or safe for

Outer Continental Shelf environmental assesment program. Final reports of principal investigators. volume 37

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

Not Available

1986-03-01

A compilation of seven final reports dealing with seal/sea lion and walrus surveys of the Navarin Basin; potential impacts of man-made noise on ringed seals; modern populations, migrations, demography, trophics, and historical status of the Pacific Walrus; distribution of marine mammals in the coastal zone of the eastern Chukchi Sea during summer and autumn; and early spring distribution, density and abundance of the Pacific Walrus in 1976.

Durability and Damage Tolerance of Bismaleimide Composites. Volume 1. Technical Report

DTIC Science & Technology

1988-06-01

Test Setup Figure 1-14, Failed Loaded Holo Static Spoifton 106 mru FaJIus Stma. FuMr Materal Spwima anT VPIU h Kok Fo Faflurep t PldN Stromsym EVIM hm...Environrnental Chamber tot ETW TesI $ 1 36 12.5 x lOft.Ibs x 7ft-lbsI- __ 8.5 14ft-bs Figure 146. Outer Mold Une Impact Locations and Eery -Levela 5.3.5

Medical Surveillance Monthly Report (MSMR). Volume 21, Number 11, November 2014

DTIC Science & Technology

2014-11-01

enzyme -linked immu- nosorbent assay (ELISA) utilizing an outer membrane protein antigen from C. jejuni Penner serotypes 1, 2, and 3.20 Acute and...Human serum antibody response to Campylobacter jejuni infection as measured in an enzyme -linked immunosorbent assay. Infect Immun. 1984;44: 292–298...Georgia: USD, Inc., 1990. 23. Coates D, Hutchinson DN, Bolton FJ. Survival of thermophilic Campylobacters on fi ngertips and their elimination by

A Highly Miniaturized Inertial Grade Gyroscope for Space Applications

NASA Technical Reports Server (NTRS)

Wiberg, D. V.; Challoner, A. D.; Shcheglov, K.; Hayworth, K.; Bae, S.; Yee, K.; Blaes, B.; DAgostino, S.; Stock, T.

2001-01-01

The evolution of inertial grade gyroscopes for space applications represents well over 50 years of technology development and an investment of hundreds of millions of dollars. The workhorse product which represents the current state-of-the art for commercially available high performance devices is the Litton-Hemishperical Resonator Gyro (HRG) Inertial Measurement Unit (IMU). This product has a performance figure of merit of 0.003 deg/hr bias drift, a volume of 567 cubic inches, weighs 19 pounds, draws about 30 watts and costs over $1 million each. Clearly devices of this magnitude are not conducive to the minimized mass, volume, power, and cost constraints of outer planet missions. An approach to breaking these potential barriers is the use of Microelectromechanical Systems (MEMS) based inertial devices. Although substantially reduced in size, mass power and cost, this approach has produced devices in the tactical performance range of greater than 1 deg/hour bias drift. This level of performance satisfies the preponderance of high market volume requirements such as automotive and tactical munitions but does not meet the limited market quantity requirements for the high precision space based market. Because of the very limited size of the space based market, there is little economic incentive for commercial fabricators of tactical grade devices to address the necessary performance improvements. The Jet Propulsion Laboratory (JPL) in conjunction with Boeing Space Systems (BSS) is addressing this void to satisfy our mutual requirements in this area. The project objective to is to achieve 0.01 deg/hr performance in an IMU which is less than 10 cubic inches in volume, weighs less than 0.5 pounds, draws less than 1 watt and is available in volume production for less than $2500. Reductions of this magnitude will be mission enabling capabilities for a variety of anticipated outer planet mission attributes such as autonomous control and docking, formation flying and robotic outposts. The improved performance will be realized using improved relative precision fabrication, enhanced vibratory drive and sense designs, and statistical data analysis.

Impacts of Outer Continental Shelf (OCS) development on recreation and tourism. Volume 1. Executive summary

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

Not Available

The study was intended to provide the Mineral Management Service (MMS) with an analytical tool to evaluate possible economic impacts from Outer Continental Shelf (OCS) development. In particular, the study was designed to provide MMS staff who work on lease sale Energy Impact Statements with an objective technique for estimating the impacts to coastal communities from events that might occur as a result of lease sales: oil spills, onshore construction, and construction of platforms offshore. The project had several specific objectives: (1) provide profiles of 1982 socio-economic conditions in coastal communities, including an analysis of the relative importance of themore » tourist industry in each coastal county; (2) develop a methodology for determining the effects of OCS development on coastal recreation; and recommend mitigation measure that may reduce the negative effect of OCS development on coastal recreation using gravity and economic effects models.« less

Compartmentalization of the outer hair cell demonstrated by slow diffusion in the extracisternal space.

PubMed

Gliko, Olga; Saggau, Peter; Brownell, William E

2009-08-19

In the outer hair cell (OHC), the extracisternal space (ECiS) is a conduit and reservoir of the molecular and ionic substrates of the lateral wall, including those necessary for electromotility. To determine the mechanisms through which molecules are transported in the ECiS of the OHC, we selectively imaged the time-dependent spatial distribution of fluorescent molecules in a <100 nm layer near the cell/glass interface of the recording chamber after their photolytic activation in a diffraction-limited volume. The effective diffusion coefficient was calculated using the analytical solution of the diffusion equation. It was found that diffusion in the ECiS is isotropic and not affected by depolarizing the OHC. Compared with free solution, the diffusion of 10 kDa dextran was slowed down in both the ECiS and the axial core by a factor of 4.6 and 1.6, respectively.

A new quadrature annular resonator for 3 T MRI based on artificial-dielectrics.

PubMed

Mikhailovskaya, Anna A; Shchelokova, Alena V; Dobrykh, Dmitry A; Sushkov, Ivan V; Slobozhanyuk, Alexey P; Webb, Andrew

2018-06-01

Dielectric resonators have previously been constructed for ultra-high frequency magnetic resonance imaging and microscopy. However, it is challenging to design these dielectric resonators at clinical field strengths due to their intrinsically large dimensions, especially when using materials with moderate permittivity. Here we propose and characterize a novel approach using artificial-dielectrics which reduces substantially the required outer diameter of the resonator. For a resonator designed to operate in a 3 Tesla scanner using water as the dielectric, a reduction in outer diameter of 37% was achieved. When used in an inductively-coupled wireless mode, the sensitivity of the artificial-dielectric resonator was measured to be slightly higher than that of a standard dielectric resonator operating in its degenerate circularly-polarized hybrid electromagnetic modes (HEM 11 ). This study demonstrates the first application of an artificial-dielectric approach to MR volume coil design. Copyright © 2018 Elsevier Inc. All rights reserved.

Multi-Shell Hollow Nanogels with Responsive Shell Permeability

PubMed Central

Schmid, Andreas J.; Dubbert, Janine; Rudov, Andrey A.; Pedersen, Jan Skov; Lindner, Peter; Karg, Matthias; Potemkin, Igor I.; Richtering, Walter

2016-01-01

We report on hollow shell-shell nanogels with two polymer shells that have different volume phase transition temperatures. By means of small angle neutron scattering (SANS) employing contrast variation and molecular dynamics (MD) simulations we show that hollow shell-shell nanocontainers are ideal systems for controlled drug delivery: The temperature responsive swelling of the inner shell controls the uptake and release, while the thermoresponsive swelling of the outer shell controls the size of the void and the colloidal stability. At temperatures between 32 °C < T < 42 °C, the hollow nanocontainers provide a significant void, which is even larger than the initial core size of the template, and they possess a high colloidal stability due to the steric stabilization of the swollen outer shell. Computer simulations showed, that temperature induced switching of the permeability of the inner shell allows for the encapsulation in and release of molecules from the cavity. PMID:26984478

A new quadrature annular resonator for 3 T MRI based on artificial-dielectrics

NASA Astrophysics Data System (ADS)

Mikhailovskaya, Anna A.; Shchelokova, Alena V.; Dobrykh, Dmitry A.; Sushkov, Ivan V.; Slobozhanyuk, Alexey P.; Webb, Andrew

2018-06-01

Dielectric resonators have previously been constructed for ultra-high frequency magnetic resonance imaging and microscopy. However, it is challenging to design these dielectric resonators at clinical field strengths due to their intrinsically large dimensions, especially when using materials with moderate permittivity. Here we propose and characterize a novel approach using artificial-dielectrics which reduces substantially the required outer diameter of the resonator. For a resonator designed to operate in a 3 Tesla scanner using water as the dielectric, a reduction in outer diameter of 37% was achieved. When used in an inductively-coupled wireless mode, the sensitivity of the artificial-dielectric resonator was measured to be slightly higher than that of a standard dielectric resonator operating in its degenerate circularly-polarized hybrid electromagnetic modes (HEM11). This study demonstrates the first application of an artificial-dielectric approach to MR volume coil design.

Safety and effectiveness of alveolar recruitment maneuvers and positive end-expiratory pressure during general anesthesia for cesarean section: a prospective, randomized trial.

PubMed

Aretha, D; Fligou, F; Kiekkas, P; Messini, C; Panteli, E; Zintzaras, E; Karanikolas, M

2017-05-01

During cesarean section, the supine position reduces functional residual capacity and worsens lung compliance. We tested the hypothesis that alveolar recruitment maneuvers and positive end-expiratory pressure improve lung compliance in women undergoing general anesthesia for cesarean section. Ninety women undergoing cesarean section were randomly assigned to one of two groups in a prospective, double-blind trial. In the alveolar recruitment maneuver group, pressure-control ventilation was used and inspiratory time was increased to 50% after delivery; positive end-expiratory pressure was increased to 20cmH 2 O and peak airway inspiratory pressure gradually increased to 45-50cmH 2 O. Volume-control ventilation was then used with low tidal volumes (6mL/kg) and positive end-expiratory pressure was reduced stepwise to 8cmH 2 O. In the control group, alveolar recruitment maneuvers were not used. Data were collected before and 3, 10 and 20min after the alveolar recruitment maneuver, before extubation and postoperatively at 10 and 20min. Dynamic compliance, peak airway inspiratory pressure, PaO 2 and PaO 2 /FiO 2 were significantly different in the alveolar recruitment maneuver group compared to controls at all time points during surgery except at baseline. Oxygen saturation was significantly greater in the alveolar recruitment maneuver group at 10 and 20min and before extubation. Dynamic compliance was 29.7-42.5% higher and peak airway inspiratory pressure 3.6-10.2% lower in the alveolar recruitment maneuver group compared to controls. The PaO 2 , PaO 2 /FiO 2 and oxygen saturation were higher (9.4-12%, 10.3-11.9% and 0.4-1.3%, respectively) in the alveolar recruitment maneuver group. Postoperatively, PaO 2 and oxygen saturation were significantly higher in the alveolar recruitment maneuver group compared to controls (PaO 2 9.2% at 10min and 8.4% at 20min, oxygen saturation 0.8% at 10min and 1.1% at 20min). There were no significant differences in hemodynamic stability or adverse events between groups. Compared to standard care, the alveolar recruitment maneuver with positive end-expiratory pressure and low tidal volumes appears safe and effective in improving lung compliance and both intraoperative and postoperative oxygenation in women undergoing general anesthesia for elective cesarean section. Copyright © 2016 Elsevier Ltd. All rights reserved.

Experimental Investigation of Relative Permeability Upscaling from the Micro-Scale to the Macro-Scale

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

Pyrak-Nolte, Laura J.; Cheng, JiangTao; Yu, Ping

2003-01-29

During this reporting period, shown experimentally that the optical coherence imaging system can acquire information on grain interfaces and void shape for a maximum depth of half a millimeter into sandstone. The measurement of interfacial area per volume (IAV), capillary pressure and saturation in two dimensional micro-models structures has shown the existence of a unique relationship among these hydraulic parameters for different pore geometry. The measurement of interfacial area per volume on a three-dimensional natural sample, i.e., sandstone, has shown the homogeneity of IAV with depth in a sample when the fluids are in equilibrium.

Salient regions detection using convolutional neural networks and color volume

NASA Astrophysics Data System (ADS)

Liu, Guang-Hai; Hou, Yingkun

2018-03-01

Convolutional neural network is an important technique in machine learning, pattern recognition and image processing. In order to reduce the computational burden and extend the classical LeNet-5 model to the field of saliency detection, we propose a simple and novel computing model based on LeNet-5 network. In the proposed model, hue, saturation and intensity are utilized to extract depth cues, and then we integrate depth cues and color volume to saliency detection following the basic structure of the feature integration theory. Experimental results show that the proposed computing model outperforms some existing state-of-the-art methods on MSRA1000 and ECSSD datasets.

Increased ventilation by fish leads to a higher risk of parasitism.

PubMed

Mikheev, Victor N; Pasternak, Anna F; Valtonen, E Tellervo; Taskinen, Jouni

2014-06-23

Fish are common intermediate hosts of trematode cercariae and their gills can potentially serve as important sites of penetration by these larval stages. We experimentally tested the hypothesis that volume of ventilation flow across the gills contributes to acquisition of these parasites by fish. We manipulated the intensity of ventilation by using different oxygen concentrations. Juvenile Oncorhynchus mykiss were individually exposed for 10 minutes to a standard dose of Diplostomum pseudospathaceum cercariae at three levels of oxygen concentration, 30, 60 and 90%. Ventilation amplitude (measured as a distance between left and right operculum), operculum beat rate, and the number of cercariae established in the eyes of fish were recorded. Fish reacted to low oxygen concentration with wider expansion of opercula (but not with increasing beat rate), leading to an increase in ventilation volume. As expected, the intensity of infection increased with decreasing oxygen saturation-probably due to a higher exposure to cercariae caused by increased ventilation under low oxygen concentrations. The number of cercariae acquired by an individual fish was positively correlated with ventilation amplitude and with ventilation volume, but not with operculum beat rate. However, even though the infection rate increased under these circumstances, the proportion of larval trematodes successfully establishing in fish eyes decreased with increasing ventilation volume, suggesting that the high flow velocity, although increasing host exposure to cercarial parasites, may interfere with the ability of these parasites to penetrate their hosts. There was no difference in the behaviour of trematode cercariae exposed to low and high oxygen concentrations. A reduction in oxygen saturation resulted in an increase in ventilation volume across the gills and in doing so an increase in the exposure of fish to cercariae. A significant correlation between ventilation volume and parasitism represents the first experimental evidence that this physiological mechanism generates variation in transmission of parasites to fish hosts. Other factors that modify ventilation flow, e.g. physiological or social stressors, are expected to produce similar effects on the transmission success of the parasites penetrating fish hosts using the gills.

Study on Optimum Design of Multi-Pole Interior Permanent Magnet Motor with Concentrated Windings

NASA Astrophysics Data System (ADS)

Kano, Yoshiaki; Kosaka, Takashi; Matsui, Nobuyuki

Interior Permanent Magnet Synchronous Motors (IPMSM) have been found in many applications because of their high-power density and high-efficiency. The existence of a complex magnetic circuit, however, makes the design of this machine quite complicated. Although FEM is commonly used in the IPMSM design, one of disadvantages is long CPU times. This paper presents a simple non-linear magnetic analysis for a multi-pole IPMSM as a preliminary design tool of FEM. The proposed analysis consists of the geometric-flux-tube-based equivalent-magnetic-circuit model. The model includes saturable permeances taking into account the local magnetic saturation in the core. As a result, the proposed analysis is capable of calculating the flux distribution and the torque characteristics in the presence of magnetic saturation. The effectiveness of the proposed analysis is verified by comparing with FEM in terms of the analytical accuracy and the computation time for two IPMSMs with different specifications. After verification, the proposed analysis-based optimum design is examined, by which the minimization of motor volume is realized while satisfying the necessary maximum torque for target applications.

Application of a constant hole volume Sanchez-Lacombe equation of state to mixtures relevant to polymeric foaming.

PubMed

von Konigslow, Kier; Park, Chul B; Thompson, Russell B

2018-06-06

A variant of the Sanchez-Lacombe equation of state is applied to several polymers, blowing agents, and saturated mixtures of interest to the polymer foaming industry. These are low-density polyethylene-carbon dioxide and polylactide-carbon dioxide saturated mixtures as well as polystyrene-carbon dioxide-dimethyl ether and polystyrene-carbon dioxide-nitrogen ternary saturated mixtures. Good agreement is achieved between theoretically predicted and experimentally determined solubilities, both for binary and ternary mixtures. Acceptable agreement with swelling ratios is found with no free parameters. Up-to-date pure component Sanchez-Lacombe characteristic parameters are provided for carbon dioxide, dimethyl ether, low-density polyethylene, nitrogen, polylactide, linear and branched polypropylene, and polystyrene. Pure fluid low-density polyethylene and nitrogen parameters exhibit more moderate success while still providing acceptable quantitative estimations. Mixture estimations are found to have more moderate success where pure components are not as well represented. The Sanchez-Lacombe equation of state is found to correctly predict the anomalous reversal of solubility temperature dependence for low critical point fluids through the observation of this behaviour in polystyrene nitrogen mixtures.

Modelling of hydrogen conditioning, retention and release in Tore Supra

NASA Astrophysics Data System (ADS)

Grisolia, C.; Horton, L. D.; Ehrenberg, J. K.

1995-04-01

A model based on a local mixing model has been previously developed at JET to explain the recovery of tritium after the first PTE experiment. This model is extended by a 0D plasma particle balance model and is applied to data from Tore Supra wall saturation experiments. With only two free parameters, representing the diffusion of hydrogen atoms and the volume recombination process between hydrogen atoms into molecules, the model can reproduce experimental data. The time evolution of the after-shot outgassing and the integral amount of particles recovered after the shot (assuming 13 m 2 of interacting surfaces between plasma and walls) are in good agreement with the experimental observations. The same set of parameters allows the model to simulate after-shot outgassing of five consecutive discharges. However, the model fails to predict the observed saturation of the walls by the plasma. Results from helium glow discharge (HeGD) can only be partially described. Good agreement with the experimental hydrogen release and its time evolution during HeGD is observed, but the model fails to describe the stability of a saturated graphite wall.

Decrease and enhancement of third-order optical nonlinearity in metal-dielectric composite films

NASA Astrophysics Data System (ADS)

Ning, Tingyin; Lu, Heng; Zhou, Yueliang; Man, Baoyuan

2018-04-01

We investigate third-order optical nonlinearity in gold nanoparticles embedded in CaCu3Ti4O12 (CCTO) films using the Z-scan method. We observe that the effective third-order nonlinear optical susceptibilities in such composite films can not only be enhanced, in line with the conventional behavior, but also be decreased, depending on the volume concentration of gold. In particular, the nonlinear absorption behavior can be changed from saturable absorption in pure CCTO films to reversed saturable absorption in composite films, and theoretically, even zero nonlinear absorption could be obtained. These results indicate that it should be possible to tune the third-order optical nonlinearity in Au:CCTO composite films by altering the gold concentration, thus making them suitable for applications in photonic devices.

Heating of a fully saturated darcian half-space: Pressure generation, fluid expulsion, and phase change

USGS Publications Warehouse

Delaney, P.

1984-01-01

Analytical solutions are developed for the pressurization, expansion, and flow of one- and two-phase liquids during heating of fully saturated and hydraulically open Darcian half-spaces subjected to a step rise in temperature at its surface. For silicate materials, advective transfer is commonly unimportant in the liquid region; this is not always the case in the vapor region. Volume change is commonly more important than heat of vaporization in determining the position of the liquid-vapor interface, assuring that the temperatures cannot be determined independently of pressures. Pressure increases reach a maximum near the leading edge of the thermal front and penetrate well into the isothermal region of the body. Mass flux is insensitive to the hydraulic properties of the half-space. ?? 1984.

A voxel-based technique to estimate the volume of trees from terrestrial laser scanner data

NASA Astrophysics Data System (ADS)

Bienert, A.; Hess, C.; Maas, H.-G.; von Oheimb, G.

2014-06-01

The precise determination of the volume of standing trees is very important for ecological and economical considerations in forestry. If terrestrial laser scanner data are available, a simple approach for volume determination is given by allocating points into a voxel structure and subsequently counting the filled voxels. Generally, this method will overestimate the volume. The paper presents an improved algorithm to estimate the wood volume of trees using a voxel-based method which will correct for the overestimation. After voxel space transformation, each voxel which contains points is reduced to the volume of its surrounding bounding box. In a next step, occluded (inner stem) voxels are identified by a neighbourhood analysis sweeping in the X and Y direction of each filled voxel. Finally, the wood volume of the tree is composed by the sum of the bounding box volumes of the outer voxels and the volume of all occluded inner voxels. Scan data sets from several young Norway maple trees (Acer platanoides) were used to analyse the algorithm. Therefore, the scanned trees as well as their representing point clouds were separated in different components (stem, branches) to make a meaningful comparison. Two reference measurements were performed for validation: A direct wood volume measurement by placing the tree components into a water tank, and a frustum calculation of small trunk segments by measuring the radii along the trunk. Overall, the results show slightly underestimated volumes (-0.3% for a probe of 13 trees) with a RMSE of 11.6% for the individual tree volume calculated with the new approach.

Study on choroidal neovascularization with anti-VEGF treatment in the mouse retina using optical coherence tomography angiography (Conference Presentation)

NASA Astrophysics Data System (ADS)

Park, Jang Ryul; Choi, WooJhon; Kim, Jaeryung; Hong, Hye Kyong; Kim, Yongjoo; Hwang, Yoonha; Park, Sang Jun; Woo, Se Joon; Kim, Pilhan; Park, Kyu Hyung; Koh, Gou Young; Oh, Wang-Yuhl

2017-02-01

To understand the pathogenesis of ophthalmic disease, utilizing small animal models such as mouse is necessary because of their ease of maintenance and availability. For identifying pathophysiology and drug development of retinal diseases in mouse model, optical coherence tomography angiography (OCTA) is promising imaging modality visualizing not only microstructure but also microvasculature. In this study, we serially imaged 3D structure and angiography of laser-induced choroidal neovascularization (CNV) in the mouse retina with/without anti-VEGF treatment. Also, the volume changes of CNV and avascular region in choroid layer are measured for identifying effects of anti-VEGF. A lab-built high-speed OCTA prototype using the wavelength-swept laser centered at 1040 nm with 230 kHz A-scan rate acquired 3-D volumetric data consisted of 1024 x 1024 x 3 A-scans. The OCTA scanned 1.7 mm x 1.7 mm area around ONH. For obtaining angiography, amplitude decorrelation from 3 consecutive B-scans at each position was generated. Seven days after the laser photocoagulation at mouse retina for generation of the laser-induced CNV, intravitreal administration of Fc and VEGF-Trap was given in the therapeutic arm. The OCTA were performed at 6, 14, 21 and 35 days after laser photocoagulation. Vasculatures of inner retina, outer retina and choroid layers were separately visualized after RPE flattening and layer segmentation. To investigate therapeutic effects of anti-VEGF treatment, the relative area and volume of CNV in outer retina layer is measured. Also, total volume of avascular zone surrounding the laser injury site in choroid layer is also analyzed.

Thermodynamic stability in elastic systems: Hard spheres embedded in a finite spherical elastic solid.

PubMed

Solano-Altamirano, J M; Goldman, Saul

2015-12-01

We determined the total system elastic Helmholtz free energy, under the constraints of constant temperature and volume, for systems comprised of one or more perfectly bonded hard spherical inclusions (i.e. "hard spheres") embedded in a finite spherical elastic solid. Dirichlet boundary conditions were applied both at the surface(s) of the hard spheres, and at the outer surface of the elastic solid. The boundary conditions at the surface of the spheres were used to describe the rigid displacements of the spheres, relative to their initial location(s) in the unstressed initial state. These displacements, together with the initial positions, provided the final shape of the strained elastic solid. The boundary conditions at the outer surface of the elastic medium were used to ensure constancy of the system volume. We determined the strain and stress tensors numerically, using a method that combines the Neuber-Papkovich spherical harmonic decomposition, the Schwartz alternating method, and Least-squares for determining the spherical harmonic expansion coefficients. The total system elastic Helmholtz free energy was determined by numerically integrating the elastic Helmholtz free energy density over the volume of the elastic solid, either by a quadrature, or a Monte Carlo method, or both. Depending on the initial position of the hard sphere(s) (or equivalently, the shape of the un-deformed stress-free elastic solid), and the displacements, either stationary or non-stationary Helmholtz free energy minima were found. The non-stationary minima, which involved the hard spheres nearly in contact with one another, corresponded to lower Helmholtz free energies, than did the stationary minima, for which the hard spheres were further away from one another.

HYPOTONIC SWELLING OF SALICYLATE-TREATED COCHLEAR OUTER HAIR CELLS

PubMed Central

Zhi, Man; Ratnanather, J. Tilak; Ceyhan, Elvan; Popel, Aleksander S.; Brownell, William E.

2007-01-01

The outer hair cell (OHC) is a hydrostat with a low hydraulic conductivity of Pf = 3×10−4 cm/s across the plasma membrane (PM) and subsurface cisterna (SSC) that make up the OHC's lateral wall. The SSC is structurally and functionally a transport barrier in normal cells that is known to be disrupted by salicylate. The effect of sodium salicylate on Pf is determined from osmotic experiments in which isolated, control and salicylate-treated OHCs were exposed to hypotonic solutions in a constant flow chamber. The value of Pf = 3.5±0.5 ×10−4 cm/s (mean ± s.e.m, n = 34) for salicylate-treated OHCs was not significantly different from Pf = 2.4±0.3 ×10−4 cm/s (mean ± s.e.m, n = 31) for untreated OHCs (p=.3302). Thus Pf is determined by the PM and is unaffected by salicylate treatment. The ratio of longitudinal strain to radial strain εz/εc = −0.76 for salicylate-treated OHCs was significantly smaller (p = .0143) from −0.72 for untreated OHCs, and is also independent of the magnitude of the applied osmotic challenge. Salicylate-treated OHCs took longer to attain a steady-state volume which is larger than that for untreated OHCs and increased in volume by 8-15% prior to hypotonic perfusion unlike sodium α-ketoglutarate treated OHCs. It is suggested that depolymerization of cytoskeletal proteins and/or glycogen maybe responsible for the large volume increase in salicylate-treated OHCs as well as the different responses to different modes of application of the hypotonic solution. PMID:17400411

Design and testing a high fuel volume fraction, externally finned, thermionic emitter.

NASA Technical Reports Server (NTRS)

Peelgren, M. L.; Ernst, D. M.

1971-01-01

A prototypical, high fuel volume fraction, thermionic emitter body was designed and tested. The emitter body is all tungsten, with a 1.40-cm ID, a 3.23-cm OD, and eight full-length axial fins. The emitter thickness is 0.15 cm while the fins and outer clad are 0.075 cm thick. Different methods of fabrication were used in making the test samples. Stress analysis was performed with a three-dimensional elastic code. Thermal testing of the samples, duplicating calculated radial temperature gradients, heatup and cooldown rates, and emitter body temperatures in operation, was performed with no structural failures noted (six heatup and cooldown cycles per sample). Further emitter analysis and testing is planned.

Osmotic contribution to the flow-driven tube formation of copper-phosphate and copper-silicate chemical gardens.

PubMed

Rauscher, Evelin; Schuszter, Gábor; Bohner, Bíborka; Tóth, Ágota; Horváth, Dezső

2018-02-21

We have produced hollow copper-containing precipitate tubes using a flow-injection technique, and characterized their linear and volume growth. It is shown that the ratio of the volume increase rate to that of pumping is constant independent of the chemical composition. It is also found that osmosis significantly contributes to the tube growth, since the inward flux of chemical species dominates during the precipitate pattern formation. The asymmetric hydrodynamic field coupled with the inherent concentration and pH gradients results in different particle morphology on the two sides of the precipitate membrane. While the tubes have a smooth outer surface, the inner walls are covered with nanoflowers for copper phosphate and with nanoballs for copper silicate.

Liquid oxygen/liquid hydrogen boost/vane pump for the advanced orbit transfer vehicles auxiliary propulsion system

NASA Technical Reports Server (NTRS)

Gluzek, F.; Mokadam, R. G.; To, I. H.; Stanitz, J. D.; Wollschlager, J.

1979-01-01

A rotating, positive displacement vane pump with an integral boost stage was designed to pump saturated liquid oxygen and liquid hydrogen for auxiliary propulsion system of orbit transfer vehicle. This unit is designed to ingest 10% vapor by volume, contamination free liquid oxygen and liquid hydrogen. The final pump configuration and the predicted performance are included.

Saturated Reconstruction of a Volume of Neocortex

DTIC Science & Technology

2015-07-30

Narayanan Kasthuri, Kenneth Jeffrey Hayworth, Daniel Raimund Berger, ..., Carey Eldin Priebe, Hanspeter Pfister, Jeff William Lichtman Correspondence...Sussman,4 Carey Eldin Priebe,5 Hanspeter Pfister,2 and Jeff William Lichtman1,* 1Department of Molecular and Cellular Biology and Center for Brain...redundancies in the synaptic connections andwanted to know if these were acci- dental . For all these reasons, we have attempted to analyze the connectivity

Closed-Loop Control of Fluid Therapy for Treatment of Hypovolemia

DTIC Science & Technology

2008-04-01

index) (Table 2). Invasive bladder catheterization and blood sampling add the use of urinary output, lactate, central venous oxygen saturation, he...for guiding burn resuscitation Time delay, renal failure, and drugs complicate interpretation Central venous oxygenation ScvO2 Global perfusion index... Central venous pressure (CVP) Sensitive to volume change Pre-injury baseline values vary Arterial pressure by transducer Real-time continuous

Effects of Thermal Status on Markers of Blood Coagulation During Simulated Hemorrhage

DTIC Science & Technology

2016-04-01

consumption would further reduce LBNP tolerance in the presence of moderate skin temperatures (35°C). Against our expectations, LBNP tolerance was not...exerted an effect sufficient in magnitude to mask any further impairments induced by additional dehydration and increases in body temperature ...Ventilatory parameters ( ventilation , tidal volume and breathing rate) were measured (body temperature and pressure saturated) using an automated gas

The experimental study of the DC dielectric breakdown strength in magnetic fluids

NASA Astrophysics Data System (ADS)

Kopčanský, P.; Tomčo, L.; Marton, K.; Koneracká, M.; Potočová, I.; Timko, M.

2004-05-01

Magnetic fluids have been studied for use as a high-voltage insulation. High-voltage measurements on magnetic fluids based on transformer oil, as a function of volume concentrations of magnetite particles and applied magnetic field, showed the increase of the DC dielectric breakdown strength opposite transformer oil, if the saturation magnetization of magnetic fluid is up to 4 mT approximately.

Multi-scale streambed topographic and discharge effects on hyporheic at the stream network scale in confined streams

Treesearch

Alessandra Marzadri; Daniele Tonina; James A. McKean; Matthew G. Tiedemann; Rohan M. Benjankar

2014-01-01

The hyporheic zone is the volume of the streambed sediment mostly saturated with stream water. It is the transitional zone between stream and shallow-ground waters and an important ecotone for benthic species, including macro-invertebrates, microorganisms, and some fish species that dwell in the hyporheic zone for parts of their lives. Most hyporheic analyses are...

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

Friedmann, S J

Carbon capture and sequestration (CCS) has emerged as a key technology for dramatic short-term reduction in greenhouse gas emissions in particular from large stationary. A key challenge in this arena is the monitoring and verification (M&V) of CO2 plumes in the deep subsurface. Towards that end, we have developed a tool that can simultaneously invert multiple sub-surface data sets to constrain the location, geometry, and saturation of subsurface CO2 plumes. We have focused on a suite of unconventional geophysical approaches that measure changes in electrical properties (electrical resistance tomography, electromagnetic induction tomography) and bulk crustal deformation (til-meters). We had alsomore » used constraints of the geology as rendered in a shared earth model (ShEM) and of the injection (e.g., total injected CO{sub 2}). We describe a stochastic inversion method for mapping subsurface regions where CO{sub 2} saturation is changing. The technique combines prior information with measurements of injected CO{sub 2} volume, reservoir deformation and electrical resistivity. Bayesian inference and a Metropolis simulation algorithm form the basis for this approach. The method can (a) jointly reconstruct disparate data types such as surface or subsurface tilt, electrical resistivity, and injected CO{sub 2} volume measurements, (b) provide quantitative measures of the result uncertainty, (c) identify competing models when the available data are insufficient to definitively identify a single optimal model and (d) rank the alternative models based on how well they fit available data. We present results from general simulations of a hypothetical case derived from a real site. We also apply the technique to a field in Wyoming, where measurements collected during CO{sub 2} injection for enhanced oil recovery serve to illustrate the method's performance. The stochastic inversions provide estimates of the most probable location, shape, volume of the plume and most likely CO{sub 2} saturation. The results suggest that the method can reconstruct data with poor signal to noise ratio and use hard constraints available from many sites and applications. External interest in the approach and method is high, and already commercial and DOE entities have requested technical work using the newly developed methodology for CO{sub 2} monitoring.« less

The study of synchronization of rhythms of microvascular blood flow and oxygen saturation during adaptive changes

NASA Astrophysics Data System (ADS)

Dunaev, Andrey V.; Sidorov, Victor V.; Krupatkin, Alexander I.; Rafailov, Ilya E.; Palmer, Scott G.; Sokolovski, Sergei G.; Stewart, Neil A.; Rafailov, Edik U.

2014-02-01

Multi-functional laser non-invasive diagnostic systems, such as "LAKK-M", allow the study of a number of microcirculatory parameters, including blood microcirculatory index (Im) (by laser Doppler flowmetry, LDF) and oxygen saturation (StO2) of skin tissue (by tissue reflectance oximetry, TRO). Such systems may provide significant information relevant to physiology and clinical medicine. The aim of this research was to use such a system to study the synchronization of microvascular blood flow and oxygen saturation rhythms under normal and adaptive change conditions. Studies were conducted with 8 healthy volunteers - 3 females and 5 males of 21-49 years. Each volunteer was subjected to basic 3 minute tests. The volunteers were observed for between 1-4 months each, totalling 422 basic tests. Measurements were performed on the palmar surface of the right middle finger and the forearm medial surface. Wavelet analysis was used to study rhythmic oscillations in LDF- and TRO-data. Tissue oxygen consumption (from arterial and venal blood oxygen saturation and nutritive flux volume) was calculated for all volunteers during "adaptive changes" as (617+/-123 AU) and (102+/-38 AU) with and without arteriovenous anastomoses (AVAs) respectively. This demonstrates increased consumption compared to normal (495+/-170 AU) and (69+/-40 AU) with and without AVAs respectively. Data analysis demonstrated the emergence of resonance and synchronization of rhythms of microvascular blood flow and oxygen saturation as an adaptive change in myogenic oscillation (vasomotion) resulting from exercise and potentially from psychoemotional stress. Synchronization of myogenic rhythms during adaptive changes suggest increased oxygen consumption resulting from increased microvascular blood flow velocity.

Comparison of two-dimensional and three-dimensional simulations of dense nonaqueous phase liquids (DNAPLs): Migration and entrapment in a nonuniform permeability field

NASA Astrophysics Data System (ADS)

Christ, John A.; Lemke, Lawrence D.; Abriola, Linda M.

2005-01-01

The influence of reduced dimensionality (two-dimensional (2-D) versus 3-D) on predictions of dense nonaqueous phase liquid (DNAPL) infiltration and entrapment in statistically homogeneous, nonuniform permeability fields was investigated using the University of Texas Chemical Compositional Simulator (UTCHEM), a 3-D numerical multiphase simulator. Hysteretic capillary pressure-saturation and relative permeability relationships implemented in UTCHEM were benchmarked against those of another lab-tested simulator, the Michigan-Vertical and Lateral Organic Redistribution (M-VALOR). Simulation of a tetrachloroethene spill in 16 field-scale aquifer realizations generated DNAPL saturation distributions with approximately equivalent distribution metrics in two and three dimensions, with 2-D simulations generally resulting in slightly higher maximum saturations and increased vertical spreading. Variability in 2-D and 3-D distribution metrics across the set of realizations was shown to be correlated at a significance level of 95-99%. Neither spill volume nor release rate appeared to affect these conclusions. Variability in the permeability field did affect spreading metrics by increasing the horizontal spreading in 3-D more than in 2-D in more heterogeneous media simulations. The assumption of isotropic horizontal spatial statistics resulted, on average, in symmetric 3-D saturation distribution metrics in the horizontal directions. The practical implication of this study is that for statistically homogeneous, nonuniform aquifers, 2-D simulations of saturation distributions are good approximations to those obtained in 3-D. However, additional work will be needed to explore the influence of dimensionality on simulated DNAPL dissolution.

Assessing Gas-Hydrate Prospects on the North Slope of Alaska - Theoretical Considerations

USGS Publications Warehouse

Lee, Myung W.; Collett, Timothy S.; Agena, Warren F.

2008-01-01

Gas-hydrate resource assessment on the Alaska North Slope using 3-D and 2-D seismic data involved six important steps: (1) determining the top and base of the gas-hydrate stability zone, (2) 'tying' well log information to seismic data through synthetic seismograms, (3) differentiating ice from gas hydrate in the permafrost interval, (4) developing an acoustic model for the reservoir and seal, (5) developing a method to estimate gas-hydrate saturation and thickness from seismic attributes, and (6) assessing the potential gas-hydrate prospects from seismic data based on potential migration pathways, source, reservoir quality, and other relevant geological information. This report describes the first five steps in detail using well logs and provides theoretical backgrounds for resource assessments carried out by the U.S. Geological Survey. Measured and predicted P-wave velocities enabled us to tie synthetic seismograms to the seismic data. The calculated gas-hydrate stability zone from subsurface wellbore temperature data enabled us to focus our effort on the most promising depth intervals in the seismic data. A typical reservoir in this area is characterized by the P-wave velocity of 1.88 km/s, porosity of 42 percent, and clay volume content of 5 percent, whereas seal sediments encasing the reservoir are characterized by the P-wave velocity of 2.2 km/s, porosity of 32 percent, and clay volume content of 20 percent. Because the impedance of a reservoir without gas hydrate is less than that of the seal, a complex amplitude variation with respect to gas-hydrate saturation is predicted, namely polarity change, amplitude blanking, and high seismic amplitude (a bright spot). This amplitude variation with gas-hydrate saturation is the physical basis for the method used to quantify the resource potential of gas hydrates in this assessment.

TRUST84. Sat-Unsat Flow in Deformable Media

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

Narasimhan, T.N.

1984-11-01

TRUST84 solves for transient and steady-state flow in variably saturated deformable media in one, two, or three dimensions. It can handle porous media, fractured media, or fractured-porous media. Boundary conditions may be an arbitrary function of time. Sources or sinks may be a function of time or of potential. The theoretical model considers a general three-dimensional field of flow in conjunction with a one-dimensional vertical deformation field. The governing equation expresses the conservation of fluid mass in an elemental volume that has a constant volume of solids. Deformation of the porous medium may be nonelastic. Permeability and the compressibility coefficientsmore » may be nonlinearly related to effective stress. Relationships between permeability and saturation with pore water pressure in the unsaturated zone may be characterized by hysteresis. The relation between pore pressure change and effective stress change may be a function of saturation. The basic calculational model of the conductive heat transfer code TRUMP is applied in TRUST84 to the flow of fluids in porous media. The model combines an integrated finite difference algorithm for numerically solving the governing equation with a mixed explicit-implicit iterative scheme in which the explicit changes in potential are first computed for all elements in the system, after which implicit corrections are made only for those elements for which the stable time-step is less than the time-step being used. Time-step sizes are automatically controlled to optimize the number of iterations, to control maximum change to potential during a time-step, and to obtain desired output information. Time derivatives, estimated on the basis of system behavior during the two previous time-steps, are used to start the iteration process and to evaluate nonlinear coefficients. Both heterogeneity and anisotropy can be handled.« less

The assessment of different production methods for hydrate bearing sediments - results from small and large scale experiments

NASA Astrophysics Data System (ADS)

Schicks, Judith; Heeschen, Katja; Spangenberg, Erik; Luzi-Helbing, Manja; Beeskow-Strauch, Bettina; Priegnitz, Mike; Giese, Ronny; Abendroth, Sven; Thaler, Jan

2017-04-01

Natural gas hydrates occur at all active and passive continental margins, in permafrost regions, and deep lakes. Since they are supposed to contain enormous amounts of methane, gas hydrates are discussed as an energy resource. For the production of gas from hydrate bearing sediments, three different production methods were tested during the last decade: depressurization, thermal and chemical stimulation as well as combinations of these methods. In the framework of the SUGAR project we developed a Large Scale Reservoir Simulator (LARS) with a total volume of 425L to test these three methods in a pilot plant scale. For this purpose we formed hydrate from methane saturated brine in sediments under conditions close to natural gas hydrate deposits. The obtained hydrate saturations varied between 40-90%. Hydrate saturation and distribution were determined using electrical resistivity tomography (ERT). The volumes of the produced gas and water were determined and the gas phase was analyzed via gas chromatography. Multi-step depressurization, thermal stimulation applying in-situ combustion as well as chemical stimulation via the injection of CO2 and a CO2-N2-mixture were tested. Depressurization and thermal stimulation appear to be less complicated compared to the chemical stimulation. For the understanding of the macroscopically observed processes on a molecular level, we also performed experiments on a smaller scale using microscopic observation, Raman spectroscopy and X-ray diffraction. The results of these experiments are of particular importance for the understanding of the processes occurring during the CO2-CH4 swapping. Under the chosen experimental conditions the observations indicate a (partial) decomposition and reformation of the hydrate structure rather than a diffusion-controlled exchange of the molecules.

Permeability of starch gel matrices and select films to solvent vapors.

PubMed

Glenn, Gregory M; Klamczynski, Artur P; Ludvik, Charles; Shey, Justin; Imam, Syed H; Chiou, Bor-Sen; McHugh, Tara; DeGrandi-Hoffman, Gloria; Orts, William; Wood, Delilah; Offeman, Rick

2006-05-03

Volatile agrochemicals such as 2-heptanone have potential in safely and effectively controlling important agricultural pests provided that they are properly delivered. The present study reports the permeability of starch gel matrices and various coatings, some of which are agricultural-based, that could be used in controlled release devices. Low-density, microcellular starch foam was made from wheat, Dent corn, and high amylose corn starches. The foam density ranged from 0.14 to 0.34 g/cm3, the pore volume ranged from 74 to 89%, and the loading capacity ranged from 2.3 to 7.2 times the foam weight. The compressive properties of the foam were not markedly affected by saturating the pore volume with silicone oil. The vapor transmission rate (VTR) and vapor permeability (VP) were measured in dry, porous starch foam and silicone-saturated starch gels. VTR values were highest in foam samples containing solvents with high vapor pressures. Silicone oil-saturated gels had lower VTR and VP values as compared to the dry foam. However, the silicone oil gel did not markedly reduce the VP for 2-heptanone and an additional vapor barrier or coating was needed to adequately reduce the evaporation rate. The VP of films of beeswax, paraffin, ethylene vinyl alcohol, a fruit film, and a laminate comprised of beeswax and fruit film was measured. The fruit film had a relatively high VP for polar solvents and a very low VP for nonpolar solvents. The laminate film provided a low VP for polar and nonpolar solvents. Perforating the fruit film portion of the laminate provided a method of attaining the target flux rate of 2-heptanone. The results demonstrate that the vapor flux rate of biologically active solvents can be controlled using agricultural materials.

The positive effects of the revised milk and cheese allowances in the special supplemental nutrition program for women, infants, and children.

PubMed

Andreyeva, Tatiana; Luedicke, Joerg; Henderson, Kathryn E; Schwartz, Marlene B

2014-04-01

In 2009, the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) implemented revisions to the WIC food packages. Milk and cheese allowances were reduced, and whole milk was disallowed for participants older than 23 months. Using a pre-post research design and scanner data from a New England supermarket chain on purchases of WIC households, this article assesses how the new WIC packages affected milk and cheese purchases and saturated fat intake among WIC households in Connecticut and Massachusetts. Milk and cheese volume purchased by 515 WIC households in Connecticut was compared before and after the WIC revisions (2009-2010) using generalized estimating equation models. Analysis for Massachusetts was descriptive. After implementation of the new WIC packages in Connecticut, whole-milk share declined from about 60% to 25% in WIC milk purchases, but remained flat at about 50% for purchases with non-WIC funds. Total milk volume fell by 14.2% (P<0.001), whole milk by half (P<0.001), and WIC-eligible cheese by 37.2% (P<0.001). Restrictions on whole milk shifted WIC purchases to reduced-fat milk in Connecticut and low-fat milk in Massachusetts, where reduced-fat milk is not permitted by WIC. The amounts of saturated fat from purchased milk and cheese declined by 85 g/month per WIC household in Connecticut and 107 g/month in Massachusetts. The 2009 WIC revisions led to a substantial decrease in purchases of whole milk and cheese among WIC families in New England. The related reduction in saturated fat intake could have important public health implications. Copyright © 2014 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Metastable Prepores in Tension-Free Lipid Bilayers

NASA Astrophysics Data System (ADS)

Ting, Christina L.; Awasthi, Neha; Müller, Marcus; Hub, Jochen S.

2018-03-01

The formation and closure of aqueous pores in lipid bilayers is a key step in various biophysical processes. Large pores are well described by classical nucleation theory, but the free-energy landscape of small, biologically relevant pores has remained largely unexplored. The existence of small and metastable "prepores" was hypothesized decades ago from electroporation experiments, but resolving metastable prepores from theoretical models remained challenging. Using two complementary methods—atomistic simulations and self-consistent field theory of a minimal lipid model—we determine the parameters for which metastable prepores occur in lipid membranes. Both methods consistently suggest that pore metastability depends on the relative volume ratio between the lipid head group and lipid tails: lipids with a larger head-group volume fraction (or shorter saturated tails) form metastable prepores, whereas lipids with a smaller head-group volume fraction (or longer unsaturated tails) form unstable prepores.

Biological Survey, Buffalo River and Outer Harbor of Buffalo, New York. Volume I.

DTIC Science & Technology

1982-06-01

these areas; and .’ , provide a functional assessment of the ecological components studied and evaluate their significance with and without project...the biological impact of spoil disposal in these areas; and I- -2- (5) To provide a functional assessment of the ecological components studied and...vegetation gradually grades into a wet red fescue meadow to the south. Srub thickets of red panicle dogwood, silky dog- wood , northern arrow- wood occur as

2005 Tri-Service Infrastructure Systems Conference and Exhibition. Volume 7, Tracks 7 and 8

DTIC Science & Technology

2005-08-04

dense soils have the potential to wash-out and erode with fluid rotary methods and over excavation and hydraulic fracturing can result. Short...circuiting is possible outside of the temporary or outer casing or through weak soils to grade. Hydraulic fracturing may take place due to soil properties...prevented the potential for hydraulic fracturing of the sensitive dam prior to grouting. Sonic drilling was selected from a ran of proposed

Nuclear electric propulsion mission engineering study. Volume 2: Final report

NASA Technical Reports Server (NTRS)

1973-01-01

Results of a mission engineering analysis of nuclear-thermionic electric propulsion spacecraft for unmanned interplanetary and geocentric missions are summarized. Critical technologies associated with the development of nuclear electric propulsion (NEP) are assessed, along with the impact of its availability on future space programs. Outer planet and comet rendezvous mission analysis, NEP stage design for geocentric and interplanetary missions, NEP system development cost and unit costs, and technology requirements for NEP stage development are studied.

International Standard Payload Rack volume

NASA Technical Reports Server (NTRS)

2001-01-01

Outer dimensions of the International Standard Payload Rack (ISPR) that will be used on the International Space Station (ISS) sets the envelope for scientists designing hardware for experiments in biological and physical sciences aboard ISS. The ISPR includes attachments to ISS utilities (electrical power, heating and cooling, data, fluids, vacuum, etc.) through standoffs that hold the racks in place in the lab modules. Usage will range from facilities that take entire racks to specialized drawers occupying a portion of a rack.

Air & Space Power Journal. Volume 26, Number 3, May-June 2012

DTIC Science & Technology

2012-06-01

strategic interest worldwide, mak- ing air and space power all the more relevant. The ability to reach any point in the world through the air and outer...States and many militaries around the world divide warfare into three levels: strategic, operational, and tactical. Most people con- ceive of the...at- tacks, strikes against the center of gravity, and the element of surprise. The operational level of war has evolved significantly since World War

AGARD Corrosion Handbook. Volume 1. Aircraft Corrosion: Causes and Case Histories

DTIC Science & Technology

1985-07-01

Anodic coatings can be formed in chromic acid, sulphuric acid, phosphoric acid or oxalic acid solutions. Chromic acid anodizing is widely used with...and consists of a thin non-porous barrier layer next to the metal with a porous outer layer that can be sealed by hydrothermal treatment in steam...anaerobic) or an oxidative (aerobic) mechanism. Various organic acids such as citric acid, oxalic acid, gluconic acid, dodecanoic acid, etc., which may be

Analysis of Drop Shapes during Electrowetting on a Dielectric

NASA Astrophysics Data System (ADS)

Daneshbod, Yousef

2005-03-01

Electrowetting refers to the electrostatic control of the interfacial energy of a liquid on a solid, primarily used for the transport of micro-liter volumes of drops on surfaces with embedded electrode arrays. In the present work, the drop is modeled as a two-dimensional lens-like conductor immersed in an infinite dielectric medium slightly above a planar conductor. A matched asymptotic expansion is used to approximate the electrostatic field surrounding the drop. The outer problem models the drop as a conducting circular segment resting on the conducting plane, each maintained at a separate constant potential. The inner problem corrects the region near the edge of the drop by modeling it as an infinite planar conducting wedge lying slightly above the conducting plane. By matching the inner and outer solutions, the charge density along the entire surface of the drop can be approximated, enabling the calculation of the total capacitance of the system. An energy minimization method similar to that of Shapiro et al. [J. Appl. Phys., 93, 5794 (2003)] is applied to the total energy consisting of the liquid/gas, liquid/solid and solid/gas surface energies, together with the electrostatic contribution, subject to the constraint that the drop volume remains constant. A modified form of the Young-Lippmann equation is thus derived that includes the contribution from the extra capacitance of the drop obtained via matched asymptotics.

Microstructure of thermally grown and deposited alumina films probed with positrons

NASA Astrophysics Data System (ADS)

Somieski, Bertram; Hulett, Lester D.; Xu, Jun; Pint, Bruce A.; Tortorelli, Peter F.; Nielsen, Bent; Asoka-Kumar, Palakkal; Suzuki, Ryoichi; Ohdaira, Toshiyuki

1999-03-01

Aluminum oxide films used for corrosion protection of iron and nickel aluminides were generated by substrate oxidation as well as plasma and physical vapor depositions. The films grown by oxidation were crystalline. The others were amorphous. Defect structures of the films were studied by positron spectroscopy techniques. Lifetimes of the positrons, and Doppler broadening of the γ photons generated by their annihilation, were measured as functions of the energies with which they were injected. In this manner, densities and sizes of the defects were determined as functions of depths from the outer surfaces of the films. Alumina films generated by oxidation had high densities of open volume defects, mainly consisting of a few aggregated vacancies. In the outer regions of the films the structures of the defects did not depend on substrate compositions. Positron lifetime measurements, and the S and W parameters extracted from Doppler broadening spectra, showed uniform distributions of defects in the crystalline Al2O3 films grown on nickel aluminide substrates, but these data indicated intermediate layers of higher defect contents at the film/substrate interfaces of oxides grown on iron aluminide substrates. Amorphous films generated by plasma and physical vapor deposition had much larger open volume defects, which caused the average lifetimes of the injected positrons to be significantly longer. The plasma deposited film exhibited a high density of large cavities.

"Where do auditory hallucinations come from?"--a brain morphometry study of schizophrenia patients with inner or outer space hallucinations.

PubMed

Plaze, Marion; Paillère-Martinot, Marie-Laure; Penttilä, Jani; Januel, Dominique; de Beaurepaire, Renaud; Bellivier, Franck; Andoh, Jamila; Galinowski, André; Gallarda, Thierry; Artiges, Eric; Olié, Jean-Pierre; Mangin, Jean-François; Martinot, Jean-Luc; Cachia, Arnaud

2011-01-01

Auditory verbal hallucinations are a cardinal symptom of schizophrenia. Bleuler and Kraepelin distinguished 2 main classes of hallucinations: hallucinations heard outside the head (outer space, or external, hallucinations) and hallucinations heard inside the head (inner space, or internal, hallucinations). This distinction has been confirmed by recent phenomenological studies that identified 3 independent dimensions in auditory hallucinations: language complexity, self-other misattribution, and spatial location. Brain imaging studies in schizophrenia patients with auditory hallucinations have already investigated language complexity and self-other misattribution, but the neural substrate of hallucination spatial location remains unknown. Magnetic resonance images of 45 right-handed patients with schizophrenia and persistent auditory hallucinations and 20 healthy right-handed subjects were acquired. Two homogeneous subgroups of patients were defined based on the hallucination spatial location: patients with only outer space hallucinations (N=12) and patients with only inner space hallucinations (N=15). Between-group differences were then assessed using 2 complementary brain morphometry approaches: voxel-based morphometry and sulcus-based morphometry. Convergent anatomical differences were detected between the patient subgroups in the right temporoparietal junction (rTPJ). In comparison to healthy subjects, opposite deviations in white matter volumes and sulcus displacements were found in patients with inner space hallucination and patients with outer space hallucination. The current results indicate that spatial location of auditory hallucinations is associated with the rTPJ anatomy, a key region of the "where" auditory pathway. The detected tilt in the sulcal junction suggests deviations during early brain maturation, when the superior temporal sulcus and its anterior terminal branch appear and merge.

[The acoustics of the open mastoid cavity (so-called "radical cavity") and its modification by surgical measures. II. Clinical studies].

PubMed

Hartwein, J

1992-09-01

The acoustic resonance of a severely altered outer ear channel (radical mastoid cavity) is investigated in a series of 18 patients who underwent revision surgery by means of in-situ measurements of the sound-pressure-level near the tympanic membrane. While the average volume of the open cavity differs from the normal ear channel for the factor 2.5, the size of the external meatus is--in average--only 20% larger. This leads to an average frequency in patients with open cavity of 1939 Hz, more than 1000 Hz less than in a series (n = 20) of normal ears (average resonance frequency: 2942 Hz). The altered acoustic behaviour of the open cavity leads to partial extensive discrepancies of the resonance-caused sound-pressure augmentation in the frequencies of 3 and 4 kHz, which are important for speech perception. The average difference is more than 10 dB (SPL). Proved surgical techniques of cavity obliteration and meatoplasty can lead to a nearly normalized acoustic behaviour of the outer ear in a statistic significant way. Due to these surgical procedures, an average postoperative resonance frequency of 2421 Hz could be reached in our patients. Especially, the resonance-caused sound-pressure augmentation in 3-4 kHz could nearly be equalized to such of a normal outer ear. Differences in the acoustic behaviour of the outer ear as can be found between patients with an open mastoid cavity and normal ears can almost be eliminated surgically.(ABSTRACT TRUNCATED AT 250 WORDS)

Turbulent/non-turbulent interfaces detected in DNS of incompressible turbulent boundary layers

NASA Astrophysics Data System (ADS)

Watanabe, T.; Zhang, X.; Nagata, K.

2018-03-01

The turbulent/non-turbulent interface (TNTI) detected in direct numerical simulations is studied for incompressible, temporally developing turbulent boundary layers at momentum thickness Reynolds number Reθ ≈ 2000. The outer edge of the TNTI layer is detected as an isosurface of the vorticity magnitude with the threshold determined with the dependence of the turbulent volume on a threshold level. The spanwise vorticity magnitude and passive scalar are shown to be good markers of turbulent fluids, where the conditional statistics on a distance from the outer edge of the TNTI layer are almost identical to the ones obtained with the vorticity magnitude. Significant differences are observed for the conditional statistics between the TNTI detected by the kinetic energy and vorticity magnitude. A widely used grid setting determined solely from the wall unit results in an insufficient resolution in a streamwise direction in the outer region, whose influence is found for the geometry of the TNTI and vorticity jump across the TNTI layer. The present results suggest that the grid spacing should be similar for the streamwise and spanwise directions. Comparison of the TNTI layer among different flows requires appropriate normalization of the conditional statistics. Reference quantities of the turbulence near the TNTI layer are obtained with the average of turbulent fluids in the intermittent region. The conditional statistics normalized by the reference turbulence characteristics show good quantitative agreement for the turbulent boundary layer and planar jet when they are plotted against the distance from the outer edge of the TNTI layer divided by the Kolmogorov scale defined for turbulent fluids in the intermittent region.

Flowmeter for determining average rate of flow of liquid in a conduit

DOEpatents

Kennerly, J.M.; Lindner, G.M.; Rowe, J.C.

1981-04-30

This invention is a compact, precise, and relatively simple device for use in determining the average rate of flow of a liquid through a conduit. The liquid may be turbulent and contain bubbles of gas. In a preferred embodiment, the flowmeter includes an electrical circuit and a flow vessel which is connected as a segment of the conduit conveying the liquid. The vessel is provided with a valved outlet and is partitioned by a vertical baffle into coaxial chambers whose upper regions are vented to permit the escape of gas. The inner chamber receives turbulent downflowing liquid from the conduit and is sized to operate at a lower pressure than the conduit, thus promoting evolution of gas from the liquid. Lower zones of the two chambers are interconnected so that the downflowing liquid establishes liquid levels in both chambers. The liquid level in the outer chamber is comparatively calm, being to a large extent isolated from the turbulence in the inner chamber once the liquid in the outer chamber has risen above the liquid-introduction zone for that chamber. Lower and upper probes are provided in the outer chamber for sensing the liquid level therein at points above its liquid-introduction zone. An electrical circuit is connected to the probes to display the time required for the liquid level in the outer chamber to successively contact the lower and upper probes. The average rate of flow through the conduit can be determined from the above-mentioned time and the vessel volume filled by the liquid during that time.

Flowmeter for determining average rate of flow of liquid in a conduit

DOEpatents

Kennerly, John M.; Lindner, Gordon M.; Rowe, John C.

1982-01-01

This invention is a compact, precise, and relatively simple device for use in determining the average rate of flow of a liquid through a conduit. The liquid may be turbulent and contain bubbles of gas. In a preferred embodiment, the flowmeter includes an electrical circuit and a flow vessel which is connected as a segment of the conduit conveying the liquid. The vessel is provided with a valved outlet and is partitioned by a vertical baffle into coaxial chambers whose upper regions are vented to permit the escape of gas. The inner chamber receives turbulent downflowing liquid from the conduit and is sized to operate at a lower pressure than the conduit, thus promoting evolution of gas from the liquid. Lower zones of the two chambers are interconnected so that the downflowing liquid establishes liquid levels in both chambers. The liquid level in the outer chamber is comparatively calm, being to a large extent isolated from the turbulence in the inner chamber once the liquid in the outer chamber has risen above the liquid-introduction zone for that chamber. Lower and upper probes are provided in the outer chamber for sensing the liquid level therein at points above its liquid-introduction zone. An electrical circuit is connected to the probes to display the time required for the liquid level in the outer chamber to successively contact the lower and upper probes. The average rate of flow through the conduit can be determined from the above-mentioned time and the vessel volume filled by the liquid during that time.

Exploring photoreceptor reflectivity via multimodal imaging of outer retinal tubulation in advanced age-related macular degeneration

PubMed Central

Litts, Katie M.; Wang, Xiaolin; Clark, Mark E.; Owsley, Cynthia; Freund, K. Bailey; Curcio, Christine A.; Zhang, Yuhua

2016-01-01

Purpose To investigate the microscopic structure of outer retinal tubulation (ORT) and optical properties of cone photoreceptors in vivo, we studied ORT appearance by multimodal imaging, including spectral domain optical coherence tomography (SD-OCT) and adaptive optics scanning laser ophthalmoscopy (AOSLO). Methods Four eyes of 4 subjects with advanced AMD underwent color fundus photography, infrared reflectance imaging, SD-OCT, and AOSLO with a high-resolution research instrument. ORT was identified in closely spaced (11 μm) SD-OCT volume scans. Results ORT in cross-sectional and en face SD-OCT was a hyporeflective area representing a lumen surrounded by a hyperreflective border consisting of cone photoreceptor mitochondria and external limiting membrane, per previous histology. In contrast, ORT by AOSLO was a hyporeflective structure of the same shape as in en face SD-OCT but lacking visualizable cone photoreceptors. Conclusion Lack of ORT cone reflectivity by AOSLO indicates that cones have lost their normal directionality and waveguiding property due to loss of outer segments and subsequent retinal remodeling. Reflective ORT cones by SD-OCT, in contrast, may depend partly on mitochondria as light scatterers within inner segments of these degenerating cells, a phenomenon enhanced by coherent imaging. Multimodal imaging of ORT provides insight into cone degeneration and reflectivity sources in OCT. PMID:27584549

Relative strengths of the calf muscles based on MRI volume measurements.

PubMed

Jeng, Clifford L; Thawait, Gaurav K; Kwon, John Y; Machado, Antonio; Boyle, James W; Campbell, John; Carrino, John A

2012-05-01

In 1985, Silver et al. published a cadaver study which determined the relative order of strength of the muscles in the calf. Muscle strength, which is proportional to volume, was obtained by dissecting out the individual muscles, weighing them, and then multiplying by the specific gravity. No similar studies have been performed using {\\it in vivo} measurements of muscle volume. Ten normal subjects underwent 3-Tesla MRI's of both lower extremities using non-fat-saturated T2 SPACE sequences. The volume for each muscle was determined by tracing the muscle contour on sequential axial images and then interpolating the volume using imaging software. The results from this study differ from Silver's original article. The lateral head of the gastrocnemius was found to be stronger than the tibialis anterior muscle. The FHL and EDL muscles were both stronger than the peroneus longus. There was no significant difference in strength between the peroneus longus and brevis muscles. This revised order of muscle strengths in the calf based on in vivo MRI findings may assist surgeons in determining the optimal tendons to transfer in order to address muscle weakness and deformity.

Sodium-dependent calcium extrusion and sensitivity regulation in retinal cones of the salamander.

PubMed Central

Nakatani, K; Yau, K W

1989-01-01

1. Membrane current was recorded from an isolated, dark-adapted salamander cone by sucking its inner segment into a tight-fitting glass pipette containing Ringer solution. The outer segment of the cell was exposed to a bath solution that could be changed rapidly. 2. After removing Na+ from the bath Ringer solution for a short period of time in darkness (the 'loading period'), a transient inward current was observed upon restoring it in bright light. A similar but longer-lasting current was observed when Na+ was restored in the light after a large Ca2+ influx was induced through the light-sensitive conductance in darkness. 3. The above transient current was not observed if Li+ or guanidinium was substituted for Na+ in the light, or if Ba2+ was substituted for Ca2+ during the dark loading period. However, a current was observed if Sr2+ was the substituting ion for Ca2+ during loading. These observations suggested that the current was associated with an electrogenic Na+-dependent Ca2+ efflux at the cone outer segment. 4. The saturated amplitude of the exchange current was 12-25 pA with a mean around 16 pA. This is very comparable to that measured in the outer segment of a salamander rod under similar conditions. 5. By comparing a known Ca2+ load in a cone outer segment to the subsequent charge transfer through the exchange, we estimated that the stoichiometry of the exchange was near 3Na+:1Ca2+. 6. With a small Ca2+ load, or in the presence of Cs+ around the inner segment, the final temporal decline of the Na+-Ca2+ exchange current was roughly exponential, with a mean time constant of about 100 ms. This decline is about four times faster than that measured in rods. We interpret the shorter time constant in cones to reflect a faster rate of decline of intracellular free Ca2+ in their outer segments resulting from the exchange activity. 7. In the absence of external Na+, and hence any Na+-dependent Ca2+ efflux, the absolute sensitivity of a cone to a dim flash was several times higher than in normal Ringer solution. 8. A roughly similar increase in light sensitivity was observed for a rod under the same conditions. 9. We conclude that the Na+-dependent Ca2+ efflux, through lowering intracellular free Ca2+ in the light, has a role in regulating the absolute light sensitivity in cones as it does in rods.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2479741

The effect of light on outer segment calcium in salamander rods

PubMed Central

Matthews, Hugh R; Fain, Gordon L

2003-01-01

Calcium acts as a second messenger in vertebrate rods, regulating the recovery phase of the light response and modulating sensitivity during light-adaptation. Since light not only decreases the outer segment calcium concentration ([Ca2+]i) by closing cyclic nucleotide-gated channels but can also increase [Ca2+]i by releasing Ca2+ from buffer sites or intracellular stores, we examined in detail the effect of light and circulating current on [Ca2+]i by making simultaneous measurements of suction pipette current and [Ca2+]i from isolated rods of the salamander Ambystoma tigrinum after incorporation of the fluorescent dye fluo-5F. When the release of Ca2+ is measured in 0 Ca2+−0 Na+ solution, minimising fluxes of Ca2+ across the plasma membrane, it is substantial only for light bright enough to bleach a significant fraction of the photopigment and is restricted to the part of the outer segment in which the bleach occurred. It is unlikely, therefore, to make a large contribution to [Ca2+]i for most of the physiological operating range of the rod. Nevertheless, since release is half-maximal for a bleach of less than 10 %, it cannot be produced by a simple mechanism such as a change in the affinity of a binding site on rhodopsin itself but must instead require some more complex interaction. In Ringer solution, the Ca2+ in the light-releasable pool can be discharged merely by the decrease in [Ca2+]i that occurs as the outer segment channels close. In steady background light or after exposure to saturating illumination, the fraction of Ca2+ in the pool decreases essentially in proportion to [Ca2+]i as if Ca2+ were being removed from a buffer site within the cytoplasm. Furthermore, [Ca2+]i itself changes in proportion to the circulating current, with little evidence for a contribution from Ca2+ release or other mechanisms of Ca2+ homeostasis. This indicates that flux of Ca2+ across the plasma membrane is the major determinant of outer segment Ca2+ concentration within the rod's normal operating light intensity range. Once Ca2+ has been discharged from the releasable pool, it is restored following dim illumination apparently as the simple result of the subsequent restoration of dark [Ca2+]i and the rebinding of Ca2+ to its release site, but after brighter light perhaps also as a consequence of regeneration of the photopigment. PMID:12949220

Pore-scale Investigation of Surfactant Induced Mobilization for the Remediation of LNAPL

NASA Astrophysics Data System (ADS)

Ghosh, J.; Tick, G. R.

2011-12-01

The presence of nonaqueous phase liquids within the subsurface can significantly limit the effectiveness of groundwater remediation. Specifically, light nonaqueous phase liquids (LNAPLs) present unique challenges as they can become "smeared" within zones above and below the water table. The aim of this research is to understand the interfacial phenomena at the pore scale influencing residual saturation of LNAPL distribution as function of media heterogeneity and remediation processes from various aquifer systems. A series of columns were packed with three types of unconsolidated sand of increasing heterogeneity in grain size distribution and were established with residual saturations of light and heavy crude oil fractions, respectively. These columns were then subjected to flooding with 0.1% anionic surfactant solution in various episodes to initiate mobilization and enhanced recovery of NAPL phase contamination. Synchrotron X-ray microtomography (SXM) imaging technology was used to study three-dimensional (3-D) distributions of crude-oil-blobs before and after sequential surfactant flooding events. Results showed that LNAPL blob distributions became more heterogeneous after each subsequent surfactant flooding episode for all porous-media systems. NAPL recovery was most effective from the homogenous porous medium whereby 100% recovery resulted after 5 pore volumes (PVs) of flushing. LNAPL within the mildly heterogeneous porous medium produced a limited but consistent reduction in saturation after each surfactant flooding episode (23% and 43% recovery for light and heavy after the 5-PV flood). The highly heterogeneous porous medium showed greater NAPL recovery potential (42% and 16% for light and heavy) only after multiple pore volumes of flushing, at which point the NAPL blobs become fragmented into the smaller fragments in response to the reduced interfacial tension. The heterogeneity of the porous media (i.e. grain-size distribution) was a dominant control on the NAPL-blob-size-distribution trapped as residual saturation. The mobility of the NAPL blobs, as a result of surfactant flooding, was primarily controlled by the relative permeability of the medium and the reduction of interfacial tension between the wetting phase (water) and NAPL phase.

PHT3D-UZF: A reactive transport model for variably-saturated porous media

USGS Publications Warehouse

Wu, Ming Zhi; Post, Vincent E. A.; Salmon, S. Ursula; Morway, Eric D.; Prommer, H.

2016-01-01

A modified version of the MODFLOW/MT3DMS-based reactive transport model PHT3D was developed to extend current reactive transport capabilities to the variably-saturated component of the subsurface system and incorporate diffusive reactive transport of gaseous species. Referred to as PHT3D-UZF, this code incorporates flux terms calculated by MODFLOW's unsaturated-zone flow (UZF1) package. A volume-averaged approach similar to the method used in UZF-MT3DMS was adopted. The PHREEQC-based computation of chemical processes within PHT3D-UZF in combination with the analytical solution method of UZF1 allows for comprehensive reactive transport investigations (i.e., biogeochemical transformations) that jointly involve saturated and unsaturated zone processes. Intended for regional-scale applications, UZF1 simulates downward-only flux within the unsaturated zone. The model was tested by comparing simulation results with those of existing numerical models. The comparison was performed for several benchmark problems that cover a range of important hydrological and reactive transport processes. A 2D simulation scenario was defined to illustrate the geochemical evolution following dewatering in a sandy acid sulfate soil environment. Other potential applications include the simulation of biogeochemical processes in variably-saturated systems that track the transport and fate of agricultural pollutants, nutrients, natural and xenobiotic organic compounds and micropollutants such as pharmaceuticals, as well as the evolution of isotope patterns.

Comparison between deep breathing exercises and incentive spirometry after CABG surgery.

PubMed

Renault, Julia Alencar; Costa-Val, Ricardo; Rosseti, Márcia Braz; Houri Neto, Miguel

2009-01-01

To compare the effects of deep breathing exercises (DBE) and the flow-oriented incentive spirometry (IS) in patients undergone coronary artery bypass grafting (CABG) through the following variables: forced vital capacity - FVC, forced expiratory volume in 1 second - FEV(1), maximal respiratory pressures and oxygen saturation. Thirty six patients in CABG postoperative period underwent thirty minutes of non-invasive ventilation during the first 24 hours after extubation and were randomly shared into two groups as following: DBE (n=18) and IS (n=18). The spirometric variables were assessed on the preoperative period and seventh postoperative day (POD). The respiratory muscle strength and oxygen saturation were assessed on the preoperative period, first, second and seventh POD. The groups were considered homogeneous in relation to the demographic and surgical variables. It has been noted fall in the values of FVC and FEV(1) between the preoperative period and the seventh POD, but without significant differences between groups. The maximal respiratory pressures showed drop in the first POD but with and partial recovery until the seventh POD, also without significant differences between groups. The oxygen saturation was the only variable that was completely recovered on the seventh POD, also without significant differences between groups. There were not observed significant differences in maximal respiratory pressures, spirometric variables and oxygen saturation in patients undergone deep breathing exercises and flow-oriented incentive spirometry after coronary artery bypass grafting.

Effect of saturated and unsaturated fatty acid supplementation on bio-plastic production under submerged fermentation.

PubMed

Srivastava, S K; Tripathi, Abhishek Dutt

2013-10-01

Polyhydroxyalkanoates (PHAs) are intracellular reserve material stored by gram-negative bacteria under nutrient-limited condition. PHAs are utilized in biodegradable plastics (bio-plastics) synthesis due to their similarity with conventional synthetic plastic. In the present study, the effect of addition of saturated and unsaturated fatty acids (palmitic acid, stearic acid, oleic acid and linoleic acid) on the production of PHAs by the soil bacterium Alcaligenes sp. NCIM 5085 was studied. Fatty acid supplementation in basal media produced saturated and unsaturated PHAs of medium and short chain length. Gas chromatography analysis of palmitic acid-supplemented media showed the presence of short chain length (scl) PHAs which could potentially serve as precursors for bio-plastic production. The scl PHA was subsequently characterized as PHB by NMR and FTIR. On the other hand, oleic acid and linoleic acid addition showed both saturated and unsaturated PHAs of different chain lengths. Palmitic acid showed maximum PHB content of 70.8 % at concentration of 15 g l -1 under shake flask cultivation. When shake flask cultivation was scaled up in a 7.5-l bioreactor (working volume 3 l), 7.6 g l -1 PHA was produced with a PHB yield (Y P/X ) and productivity of 75.89 % and 0.14 g l -1  h, respectively.

BIOCHEMICAL AND ULTRASTRUCTURAL PROPERTIES OF A MITOCHONDRIAL INNER MEMBRANE FRACTION DEFICIENT IN OUTER MEMBRANE AND MATRIX ACTIVITIES

PubMed Central

Chan, T. L.; Greenawalt, John W.; Pedersen, Peter L.

1970-01-01

Treatment of the inner membrane matrix fraction of rat liver mitochondria with the nonionic detergent Lubrol WX solubilized about 70% of the total protein and 90% or more of the following matrix activities: malate dehydrogenase, glutamate dehydrogenase, and isocitrate dehydrogenase (NADP). The Lubrol-insoluble fraction was enriched in cytochromes, phospholipids, and a Mg++-stimulated ATPase activity. Less than 2% of the total mitochondrial activity of monoamine oxidase, an outer membrane marker, or adenylate kinase, an intracristal space marker could be detected in this inner membrane fraction. Electron micrographs of negatively stained preparations showed vesicles (≤0.4 µ diameter) literally saturated on the periphery with the 90 A ATPase particles. These inner membrane vesicles, which appeared for the most part to be inverted with respect to the normal inner membrane configuration in intact mitochondria, retained the succinicoxidase portion of the electron-transport chain, an intact phosphorylation site II with a high affinity for ADP, and the capacity to accumulate Ca++. A number of biochemical properties characteristic of intact mitochondria and the inner membrane matrix fraction, however, were either absent or markedly deficient in the inner membrane vesicles. These included stimulation of respiration by either ADP or 2,4-dinitrophenol, oligomycin-sensitive ADP-ATP exchange activity, atractyloside sensitivity of adenine nucleotide requiring reactions, and a stimulation of the Mg++-ATPase by 2,4-dinitrophenol. PMID:4254678

Investigating distribution patterns of airborne magnetic grains trapped in tree barks in Milan, Italy: insights for pollution mitigation strategies

NASA Astrophysics Data System (ADS)

Vezzola, Laura C.; Muttoni, Giovanni; Merlini, Marco; Rotiroti, Nicola; Pagliardini, Luca; Hirt, Ann M.; Pelfini, Manuela

2017-08-01

High levels of air particulate matter (PM) have been positively correlated with respiratory diseases. In this study, we performed a biomonitoring investigation using samples of bark obtained from trees in a selected study area in the city of Milan (northern Italy). Here, we analyse the magnetic and mineralogical properties of the outer and inner barks of 147 trees, finding that magnetite is the prevalent magnetic mineral. The relative concentration of magnetite is estimated in the samples using saturation isothermal remanent magnetization (SIRM) and hysteresis parameters. We also make a first-order estimate of absolute magnetite concentration from the SIRM. The spatial distribution of the measured magnetic parameters is evaluated as a function of the distance to the main sources of magnetic PM in the study area, for example, roads and tram stops. These results are compared with data from a substantially pollution-free control site in the Central Italian Alps. Magnetic susceptibility, SIRM and magnetite concentration are found to be the highest in the outer tree barks for samples that are closest to roads and especially tram stops. In contrast, the inner bark samples are weakly magnetic and are not correlated to the distance from magnetite PM sources. The results illustrate that trees play an important role acting as a sink for airborne PM in urban areas.

Dynamic domains of the Derviche Tourneur sodium experiment: Simulations of a spherical magnetized Couette flow

NASA Astrophysics Data System (ADS)

Kaplan, E. J.; Nataf, H.-C.; Schaeffer, N.

2018-03-01

The Derviche Tourneur sodium experiment, a spherical Couette magnetohydrodynamics experiment with liquid sodium as the medium and a dipole magnetic field imposed from the inner sphere, recently underwent upgrades to its diagnostics to better characterize the flow and induced magnetic fields with global rotation. In tandem with the upgrades, a set of direct numerical simulations were run to give a more complete view of the fluid and magnetic dynamics at various rotation rates of the inner and outer spheres. These simulations reveal several dynamic regimes, determined by the Rossby number. At positive differential rotation there is a regime of quasigeostrophic flow, with low levels of fluctuations near the outer sphere. Negative differential rotation shows a regime of what appear to be saturated hydrodynamic instabilities at low negative differential rotation, followed by a regime where filamentary structures develop at low latitudes and persist over five to ten differential rotation periods as they drift poleward. We emphasize that all these coherent structures emerge from turbulent flows. At least some of them seem to be related to linear instabilities of the mean flow. The simulated flows can produce the same measurements as those that the physical experiment can take, with signatures akin to those found in the experiment. This paper discusses the relation between the internal velocity structures of the flow and their magnetic signatures at the surface.

Growth and FIB-SEM analyses of C60 microtubes vertically synthesized on porous alumina membranes

NASA Astrophysics Data System (ADS)

Miyazawa, Kun'ichi; Kuriyama, Ryota; Shimomura, Shuichi; Wakahara, Takatsugu; Tachibana, Masaru

2014-02-01

The vertical growth of C60 microtubes (C60MTs) on anodic aluminum oxide (AAO) membranes was investigated. The C60MT size dependence on isopropyl alcohol (IPA) injection rate, into C60-saturated toluene solutions through AAO membranes, was measured. A longitudinal section of the interface between a vertically grown C60MT (V-C60MT) and a membrane was prepared by focused ion beam processing, and observed with scanning electron microscopy. No cracking was observed along the interface, suggesting good bonding. V-C60MTs exhibited spiral growth. V-C60MT planar density, wall thickness and aspect ratio all decreased with increasing IPA injection rate. The relationships among length, inner and outer diameters of V-C60MTs were also investigated by varying IPA injection rate.

Development of an MRI biomarker sensitive to tetrameric visual arrestin 1 and its reduction via light-evoked translocation in vivo

PubMed Central

Berkowitz, Bruce A.; Gorgis, Jawan; Patel, Ankit; Baameur, Faiza; Gurevich, Vsevolod V.; Craft, Cheryl M.; Kefalov, Vladimir J.; Roberts, Robin

2015-01-01

Rod tetrameric arrestin 1 (tet-ARR1), stored in the outer nuclear layer/inner segments in the dark, modulates photoreceptor synaptic activity; light exposure stimulates a reduction via translocation to the outer segments for terminating G-protein coupled phototransduction signaling. Here, we test the hypothesis that intraretinal spin-lattice relaxation rate in the rotating frame (1/T1ρ), an endogenous MRI contrast mechanism, has high potential for evaluating rod tet-ARR1 and its reduction via translocation. Dark- and light-exposed mice (null for the ARR1 gene, overexpressing ARR1, diabetic, or wild type with or without treatment with Mn2+, a calcium channel probe) were studied using 1/T1ρ MRI. Immunohistochemistry and single-cell recordings of the retinas were also performed. In wild-type mice with or without treatment with Mn2+, 1/T1ρ of avascular outer retina (64% to 72% depth) was significantly (P < 0.05) greater in the dark than in the light; a significant (P < 0.05) but opposite pattern was noted in the inner retina (<50% depth). Light-evoked outer retina Δ1/T1ρ was absent in ARR1-null mice and supernormal in overexpressing mice. In diabetic mice, the outer retinal Δ1/T1ρ pattern suggested normal dark-to-light tet-ARR1 translocation and chromophore content, conclusions confirmed ex vivo. Light-stimulated Δ1/T1ρ in inner retina was linked to changes in blood volume. Our data support 1/T1ρ MRI for noninvasively assessing rod tet-ARR1 and its reduction via protein translocation, which can be combined with other metrics of retinal function in vivo.—Berkowitz, B. A., Gorgis, J., Patel, A., Baameur, F., Gurevich, V. V., Craft, C. M., Kefalov, V. J., Roberts, R. Development of an MRI biomarker sensitive to tetrameric visual arrestin 1 and its reduction via light-evoked translocation in vivo. PMID:25351983