High-pressure and high-temperature neutron reflectometry cell for solid-fluid interface studies

NASA Astrophysics Data System (ADS)

Wang, P.; Lerner, A. H.; Taylor, M.; Baldwin, J. K.; Grubbs, R. K.; Majewski, J.; Hickmott, D. D.

2012-07-01

A new high pressure-temperature ( P - T Neutron Reflectometry (NR) cell developed at Los Alamos National Laboratory (LANL) is described that significantly extends the capabilities of solid/fluid interface investigations up to 200MPa ( ensuremath ˜ 30000 psi) and 200 ° C. The cell's simple aluminum construction makes it light and easy to operate while thinned neutron windows allow up to 74% neutron transmission. The wide-open neutron window geometry provides a maximum theoretical ensuremath Qz range of 0.31Å-1. Accurate T and P controls are integrated on the cell's control panel. Built-in powder wells provide the ability to saturate fluids with reactive solids, producing aqueous species and/or decomposing into gaseous phases. The cell is designed for samples up to 50.8mm in diameter and 10.0mm in thickness. An experiment investigating the high P - T corrosion behavior of aluminum on LANL's Surface ProfilE Analysis Reflectometer (SPEAR) is presented, demonstrating the functioning and capability of the cell. Finally, outlooks on high P - T NR applications and perspectives on future research are discussed.

Coupled charge migration and fluid mixing in reactive fronts

NASA Astrophysics Data System (ADS)

Ghosh, Uddipta; Bandopadhyay, Aditya; Jougnot, Damien; Le Borgne, Tanguy; Meheust, Yves

2017-04-01

Quantifying fluid mixing in subsurface environments and its consequence on biogeochemical reactions is of paramount importance owing to its role in processes such as contaminant migration, aquifer remediation, CO2 sequestration or clogging processes, to name a few (Dentz et al. 2011). The presence of strong velocity gradients in porous media is expected to lead to enhanced diffusive mixing and augmented reaction rates (Le Borgne et al. 2014). Accurate in situ imaging of subsurface reactive solute transport and mixing remains to date a challenging proposition: the opacity of the medium prevents optical imaging and field methods based on tracer tests do not provide spatial information. Recently developed geophysical methods based on the temporal monitoring of electrical conductivity and polarization have shown promises for mapping and monitoring biogeochemical reactions in the subsurface although it remains challenging to decipher the multiple sources of electrical signals (e.g. Knight et al. 2010). In this work, we explore the coupling between fluid mixing, reaction and charge migration in porous media to evaluate the potential of mapping reaction rates from electrical measurements. To this end, we develop a new theoretical framework based on a lamellar mixing model (Le Borgne et al. 2013) to quantify changes in electrical mobility induced by chemical reactions across mixing fronts. Electrical conductivity and induced polarization are strongly dependent on the concentration of ionic species, which in turn depend on the local reaction rates. Hence, our results suggest that variation in real and complex electrical conductivity may be quantitatively related to the mixing and reaction dynamics. Thus, the presented theory provides a novel upscaling framework for quantifying the coupling between mixing, reaction and charge migration in heterogeneous porous media flows. References: Dentz. et al., Mixing, spreading and reaction in heterogeneous media: A brief review J

Syn-metamorphic interconnected porosity during blueschist facies reactive fluid fluxes at the slab-mantle interface

NASA Astrophysics Data System (ADS)

Konrad-Schmolke, Matthias; Klitscher, Nicolai; Halama, Ralf; Wirth, Richard; Morales, Luiz

2017-04-01

At the slab-mantle interface in subdution zones fluids released from the downgoing plate infiltrate into a mechanical mixture of rocks with different chemical compositions, different hydration states and different rheological behaviour resulting in a highly reactive mélange within a steep temperature gradient. Fluid pathways, reaction mechanisms and reaction rates of such fluxes, however, are poorly known, although these parameters are thought to be crucial for several seismic phenomena, such as those commonly referred to as slow earthquakes (e.g., episodic tremor and slip (ETS)). We discovered syn-metamorphic fluid-pathways in the form of interconnected metamorphic porosity in eclogite and blueschist facies mélange rocks from the Franciscan Complex near Jenner, CA. The sampled rocks occur as rigid mafic blocks of different sizes (cm to decametre) in a weak chlorite-serpentine matrix interpreted to be an exhumed slab-mantle interface. Some of these mafic blocks record reactive fluid infiltration that transforms dry eclogite into hydrous blueschist with a sharp reaction front clearly preserved and visible from outcrop- down to µm-scale. We can show that a number of interconnected fluid pathways, such as interconnected metamorphic porosity between reacting omphacite and newly formed sodic amphibole enabled fluid infiltration and interface coupled solution-reprecipitation reactions at blueschist facies conditions. We investigated the different types of fluid pathways with TEM and visualized their interconnectivity with 3D focused ion beam (FIB) sections. The eclogitic parts of the samples preserve porous primary omphacite as a product of amphibole and epidote breakdown during subduction. This primary porosity in omphacite I results from a negative volume change in the solids during amphibole and epidote dehydration. The resulting pores appear as (fluid filled) elongated inclusions the orientations of which are controlled by the omphacite lattice. During

Evaluation of continuous ambulatory peritoneal dialysis fluid C-reactive protein in patients with peritonitis.

PubMed

Ramanathan, Kumaresan; Padmanabhan, Giri; Vijayaraghavan, Bhooma

2016-05-01

Severe peritonitis causing death is one of the most devastating complications of peritoneal dialysis (PD). Since the predictive value of C-reactive protein (CRP) in PD fluid has not been assessed, the objective of the present study is to evaluate its predictive value and clinical correlation in patients on PD with peritonitis. One hundred and twenty patients on continuous ambulatory PD (CAPD) were enrolled and their serum and fluid CRP (Fl. CRP) were evaluated at the start of CAPD. All patients who developed peritonitis were further evaluated for serum and fluid CRP. The patients were categorized into four groups, namely: normal patients (control group), patients with peritonitis, patients with peritonitis leading to catheter removal, and death due to peritonitis. Sixty-five patients developed peritonitis of whom, catheter removal was performed in eight patients. Five patients died due to peritonitis-related complications. Fl. CRP showed a significant difference among the three groups, unlike S. CRP. Estimation of CRP in the peritoneal fluid may be a useful marker to monitor the onset of peritonitis.

Method of measuring reactive acoustic power density in a fluid

DOEpatents

Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

1985-01-01

A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

Method of measuring reactive acoustic power density in a fluid

DOEpatents

Wheatley, J.C.; Swift, G.W.; Migliori, A.

1985-09-03

A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas. 5 figs.

Measurement of Reactive Oxygen Species, Reactive Nitrogen Species, and Redox-Dependent Signaling in the Cardiovascular System

PubMed Central

Griendling, Kathy K.; Touyz, Rhian M.; Zweier, Jay L.; Dikalov, Sergey; Chilian, William; Chen, Yeong-Renn; Harrison, David G.; Bhatnagar, Aruni

2017-01-01

Reactive oxygen species and reactive nitrogen species are biological molecules that play important roles in cardiovascular physiology and contribute to disease initiation, progression, and severity. Because of their ephemeral nature and rapid reactivity, these species are difficult to measure directly with high accuracy and precision. In this statement, we review current methods for measuring these species and the secondary products they generate and suggest approaches for measuring redox status, oxidative stress, and the production of individual reactive oxygen and nitrogen species. We discuss the strengths and limitations of different methods and the relative specificity and suitability of these methods for measuring the concentrations of reactive oxygen and reactive nitrogen species in cells, tissues, and biological fluids. We provide specific guidelines, through expert opinion, for choosing reliable and reproducible assays for different experimental and clinical situations. These guidelines are intended to help investigators and clinical researchers avoid experimental error and ensure high-quality measurements of these important biological species. PMID:27418630

Reactive-brittle dynamics in peridotite alteration

NASA Astrophysics Data System (ADS)

Evans, O.; Spiegelman, M. W.; Kelemen, P. B.

2017-12-01

The interactions between reactive fluids and brittle solids are critical in Earth dynamics. Implications of such processes are wide-ranging: from earthquake physics to geologic carbon sequestration and the cycling of fluids and volatiles through subduction zones. Peridotite alteration is a common feature in many of these processes, which - despite its obvious importance - is relatively poorly understood from a geodynamical perspective. In particular, alteration reactions are thought to be self-limiting in nature, contradicting observations of rocks that have undergone 100% hydration/carbonation. One potential explanation of this observation is the mechanism of "reaction-driven cracking": that volume changes associated with these reactions are large enough to fracture the surrounding rock, leading to a positive feedback where new reactive surfaces are exposed and fluid pathways are created. The purpose of this study is to investigate the relative roles of reaction, elastic stresses and surface tension in alteration reactions. In this regard we derive a system of equations describing reactive fluid flow in an elastically deformable porous media, and explore them via a combination of analytic and numerical solutions. Using this model we show that the final stress state of a dry peridotite that has undergone reaction depends strongly on the rates of reaction versus fluid transport: significant fluid flow driven by pressure and/or surface tension gradients implies higher fractions of serpentinization, leaving behind a highly stressed residuum of partially reacted material. Using a model set-up that mimics a cylindrical triaxial apparatus we predict that the resulting stresses would lead to tensile failure and the generation of radially oriented cracks.

Method For Reactivating Solid Catalysts Used For Alklation Reactions

DOEpatents

Ginosar, Daniel M.; Thompson, David N.; Coates, Kyle; Zalewski, David J.; Fox, Robert V.

2005-05-03

A method for reactivating a solid alkylation catalyst is provided which can be performed within a reactor that contains the alkylation catalyst or outside the reactor. Effective catalyst reactivation is achieved whether the catalyst is completely deactivated or partially deactivated. A fluid reactivating agent is employed to dissolve catalyst fouling agents and also to react with such agents and carry away the reaction products. The deactivated catalyst is contacted with the fluid reactivating agent under pressure and temperature conditions such that the fluid reactivating agent is dense enough to effectively dissolve the fouling agents and any reaction products of the fouling agents and the reactivating agent. Useful pressures and temperatures for reactivation include near-critical, critical, and supercritical pressures and temperatures for the reactivating agent. The fluid reactivating agent can include, for example, a branched paraffin containing at least one tertiary carbon atom, or a compound that can be isomerized to a molecule containing at least one tertiary carbon atom.

Method for reactivating solid catalysts used in alkylation reactions

DOEpatents

Ginosar, Daniel M.; Thompson, David N.; Coates, Kyle; Zalewski, David J.; Fox, Robert V.

2003-06-17

A method for reactivating a solid alkylation catalyst is provided which can be performed within a reactor that contains the alkylation catalyst or outside the reactor. Effective catalyst reactivation is achieved whether the catalyst is completely deactivated or partially deactivated. A fluid reactivating agent is employed to dissolve catalyst fouling agents and also to react with such agents and carry away the reaction products. The deactivated catalyst is contacted with the fluid reactivating agent under pressure and temperature conditions such that the fluid reactivating agent is dense enough to effectively dissolve the fouling agents and any reaction products of the fouling agents and the reactivating agent. Useful pressures and temperatures for reactivation include near-critical, critical, and supercritical pressures and temperatures for the reactivating agent. The fluid reactivating agent can include, for example, a branched paraffin containing at least one tertiary carbon atom, or a compound that can be isomerized to a molecule containing at least one tertiary carbon atom.

Numerical modeling of coupled variably saturated fluid flow and reactive transport with fast and slow chemical reactions

NASA Astrophysics Data System (ADS)

Yeh, Gour-Tsyh (George); Siegel, Malcolm D.; Li, Ming-Hsu

2001-02-01

The couplings among chemical reaction rates, advective and diffusive transport in fractured media or soils, and changes in hydraulic properties due to precipitation and dissolution within fractures and in rock matrix are important for both nuclear waste disposal and remediation of contaminated sites. This paper describes the development and application of LEHGC2.0, a mechanistically based numerical model for simulation of coupled fluid flow and reactive chemical transport, including both fast and slow reactions in variably saturated media. Theoretical bases and numerical implementations are summarized, and two example problems are demonstrated. The first example deals with the effect of precipitation/dissolution on fluid flow and matrix diffusion in a two-dimensional fractured media. Because of the precipitation and decreased diffusion of solute from the fracture into the matrix, retardation in the fractured medium is not as large as the case wherein interactions between chemical reactions and transport are not considered. The second example focuses on a complicated but realistic advective-dispersive-reactive transport problem. This example exemplifies the need for innovative numerical algorithms to solve problems involving stiff geochemical reactions.

Moving overlapping grids with adaptive mesh refinement for high-speed reactive and non-reactive flow

NASA Astrophysics Data System (ADS)

Henshaw, William D.; Schwendeman, Donald W.

2006-08-01

We consider the solution of the reactive and non-reactive Euler equations on two-dimensional domains that evolve in time. The domains are discretized using moving overlapping grids. In a typical grid construction, boundary-fitted grids are used to represent moving boundaries, and these grids overlap with stationary background Cartesian grids. Block-structured adaptive mesh refinement (AMR) is used to resolve fine-scale features in the flow such as shocks and detonations. Refinement grids are added to base-level grids according to an estimate of the error, and these refinement grids move with their corresponding base-level grids. The numerical approximation of the governing equations takes place in the parameter space of each component grid which is defined by a mapping from (fixed) parameter space to (moving) physical space. The mapped equations are solved numerically using a second-order extension of Godunov's method. The stiff source term in the reactive case is handled using a Runge-Kutta error-control scheme. We consider cases when the boundaries move according to a prescribed function of time and when the boundaries of embedded bodies move according to the surface stress exerted by the fluid. In the latter case, the Newton-Euler equations describe the motion of the center of mass of the each body and the rotation about it, and these equations are integrated numerically using a second-order predictor-corrector scheme. Numerical boundary conditions at slip walls are described, and numerical results are presented for both reactive and non-reactive flows that demonstrate the use and accuracy of the numerical approach.

How reactive fluids alter fracture walls and affect shale-matrix accessibility

NASA Astrophysics Data System (ADS)

Fitts, J. P.; Deng, H.; Peters, C. A.

2014-12-01

Predictions of mass transfer across fracture boundaries and fluid flow in fracture networks provide fundamental inputs into risk and life cycle assessments of geologic energy technologies including oil and gas extraction, geothermal energy systems and geologic CO2 storage. However, major knowledge gaps exist due to the lack of experimental observations of how reactive fluids alter the pore structures and accessible surface area within fracture boundaries that control the mass transfer of organics, metals and salts, and influence fluid flow within the fracture. To investigate the fracture and rock matrix properties governing fracture boundary alteration, we developed a new flow-through cell that enables time-dependent 2D x-ray imaging of mineral dissolution and/or precipitation at a fracture surface. The parallel plate design provides an idealized fracture geometry to investigate the relationship between flow rate, reaction rate, and mineral spatial heterogeneity and variation. In the flow-cell, a carbonate-rich sample of Eagle Ford shale was reacted with acidified brine. The extent and rate of mineral dissolution were correlated with calcite abundance relative to less soluble silicate minerals. Three-dimensional x-ray tomography of the reacted fracture wall shows how calcite dissolution left behind a porous network of silicate minerals. And while this silicate network essentially preserved the location of the initial fracture wall, the pore network structures within the fracture boundary were dramatically altered, such that the accessible surface area of matrix components increased significantly. In a second set of experiments with a limestone specimen, however, the extent of dissolution and retreat of the fracture wall was not strictly correlated with the occurrence of calcite. Instead, the pattern and extent of dissolution suggested secondary causes such as calcite morphology, the presence of argillaceous minerals and other diagenetic features. Our experiments

Borylnitrenes: electrophilic reactive intermediates with high reactivity towards C-H bonds.

PubMed

Bettinger, Holger F; Filthaus, Matthias

2010-12-21

Borylnitrenes (catBN 3a and pinBN 3b; cat = catecholato, pin = pinacolato) are reactive intermediates that show high tendency towards insertion into the C-H bonds of unactivated hydrocarbons. The present article summarizes the matrix isolation investigations that were aimed at identifying, characterizing and investigating the chemical behaviour of 3a by spectroscopic means, and of the experiments in solution and in the gas phase that were performed with 3b. Comparison with the reactivity reported for difluorovinylidene 1a in solid argon indicates that 3a shows by and large similar reactivity, but only after photochemical excitation. The derivative 3b inserts into the C-H bonds of hydrocarbon solvents in high yields and thus allows the formation of primary amines, secondary amines, or amides from "unreactive" hydrocarbons. It can also be used for generation of methylamine or methylamide from methane in the gas phase at room temperature. Remaining challenges in the chemistry of borylnitrenes are briefly summarized.

C-O-H-N fluids circulations and graphite precipitation in reactivated Hudsonian shear zones during basement uplift of the Wollaston-Mudjatik Transition Zone: Example of the Cigar Lake U deposit

NASA Astrophysics Data System (ADS)

Martz, Pierre; Cathelineau, Michel; Mercadier, Julien; Boiron, Marie-Christine; Jaguin, Justine; Tarantola, Alexandre; Demacon, Mickael; Gerbeaud, Olivier; Quirt, David; Doney, Amber; Ledru, Patrick

2017-12-01

Graphitic shear zones are spatially associated with unconformity-related uranium deposits that are located around the unconformity between the strata of the Paleo- to Mesoproterozoic Athabasca Basin (Saskatchewan, Canada) and its underlying Archean to Paleoproterozoic basement. The present study focuses on basement-hosted ductile-brittle graphitic shear zones near the Cigar Lake U deposit, one of the largest unconformity-related U deposits. The goal of the study is to decipher the pre-Athabasca Basin fluid migration history recorded within such structures and its potential role on the formation of such exceptional deposit. Dominantly C-O-H(-N) metamorphic fluids have been trapped in Fluid Inclusion Planes (FIPs) in magmatic quartz within ductile-brittle graphitic shear zones active during retrograde metamorphism associated with the formation of the Wollaston-Mudjatik Transition Zone (WMTZ) between ca. 1805 and 1720 Ma. Such fluids show a compositional evolution along the retrograde path, from a dense and pure CO2 fluid during the earliest stages, through a lower density CO2 ± CH4-N2 (± H2O) fluid and, finally, to a very low density CH4-N2 fluid. Statistical study of the orientation, distribution, proportion, and chemical characterization of the FIPs shows that: i) CO2 (δ13CCO2 around - 9‰ PDB) from decarbonation reactions and/or partial water-metamorphic graphite equilibrium initially migrated regionally and pervasively under lithostatic conditions at about 500 to 800 °C and 150 to 300 MPa. Such P-T conditions attest to a high geothermal gradient of around 60 to 90 °C/km, probably related to rapid exhumation of the basement or a large-scale heat source. ii) Later brittle reactivation of the shear zone at around 450 °C and 25-50 MPa favored circulation of CO2-CH4-N2(± H2O) fluids in equilibrium with metamorphic graphite (δ13CCO2 around - 14‰) under hydrostatic conditions and only within the shear zones. Cooling of these fluids and the water uptake linked

High-throughput sequencing of TCR repertoires in multiple sclerosis reveals intrathecal enrichment of EBV-reactive CD8+ T cells.

PubMed

Lossius, Andreas; Johansen, Jorunn N; Vartdal, Frode; Robins, Harlan; Jūratė Šaltytė, Benth; Holmøy, Trygve; Olweus, Johanna

2014-11-01

Epstein-Barr virus (EBV) has long been suggested as a pathogen in multiple sclerosis (MS). Here, we used high-throughput sequencing to determine the diversity, compartmentalization, persistence, and EBV-reactivity of the T-cell receptor (TCR) repertoires in MS. TCR-β genes were sequenced in paired samples of cerebrospinal fluid (CSF) and blood from patients with MS and controls with other inflammatory neurological diseases. The TCR repertoires were highly diverse in both compartments and patient groups. Expanded T-cell clones, represented by TCR-β sequences >0.1%, were of different identity in CSF and blood of MS patients, and persisted for more than a year. Reference TCR-β libraries generated from peripheral blood T cells reactive against autologous EBV-transformed B cells were highly enriched for public EBV-specific sequences and were used to quantify EBV-reactive TCR-β sequences in CSF. TCR-β sequences of EBV-reactive CD8+ T cells, including several public EBV-specific sequences, were intrathecally enriched in MS patients only, whereas those of EBV-reactive CD4+ T cells were also enriched in CSF of controls. These data provide evidence for a clonally diverse, yet compartmentalized and persistent, intrathecal T-cell response in MS. The presented strategy links TCR sequence to intrathecal T-cell specificity, demonstrating enrichment of EBV-reactive CD8+ T cells in MS. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly reactive light-dependent monoterpenes in the Amazon

DOE PAGES

Jardine, A. B.; Jardine, K. J.; Fuentes, J. D.; ...

2015-03-06

Despite orders of magnitude difference in atmospheric reactivity and great diversity in biological functioning, little is known about monoterpene speciation in tropical forests. Here we report vertically resolved ambient air mixing ratios for 12 monoterpenes in a central Amazon rainforest including observations of the highly reactive cis-β-ocimene (160 ppt), trans-β-ocimene (79 ppt), and terpinolene (32 ppt) which accounted for an estimated 21% of total monoterpene composition yet 55% of the upper canopy monoterpene ozonolysis rate. All 12 monoterpenes showed a mixing ratio peak in the upper canopy, with three demonstrating subcanopy peaks in 7 of 11 profiles. Leaf level emissionsmore » of highly reactive monoterpenes accounted for up to 1.9% of photosynthesis confirming light-dependent emissions across several Amazon tree genera. These results suggest that highly reactive monoterpenes play important antioxidant roles during photosynthesis in plants and serve as near-canopy sources of secondary organic aerosol precursors through atmospheric photooxidation via ozonolysis.« less

Highly reactive light-dependent monoterpenes in the Amazon

NASA Astrophysics Data System (ADS)

Jardine, A. B.; Jardine, K. J.; Fuentes, J. D.; Martin, S. T.; Martins, G.; Durgante, F.; Carneiro, V.; Higuchi, N.; Manzi, A. O.; Chambers, J. Q.

2015-03-01

Despite orders of magnitude difference in atmospheric reactivity and great diversity in biological functioning, little is known about monoterpene speciation in tropical forests. Here we report vertically resolved ambient air mixing ratios for 12 monoterpenes in a central Amazon rainforest including observations of the highly reactive cis-β-ocimene (160 ppt), trans-β-ocimene (79 ppt), and terpinolene (32 ppt) which accounted for an estimated 21% of total monoterpene composition yet 55% of the upper canopy monoterpene ozonolysis rate. All 12 monoterpenes showed a mixing ratio peak in the upper canopy, with three demonstrating subcanopy peaks in 7 of 11 profiles. Leaf level emissions of highly reactive monoterpenes accounted for up to 1.9% of photosynthesis confirming light-dependent emissions across several Amazon tree genera. These results suggest that highly reactive monoterpenes play important antioxidant roles during photosynthesis in plants and serve as near-canopy sources of secondary organic aerosol precursors through atmospheric photooxidation via ozonolysis.

Fracture Reactivation in Chemically Reactive Rock Systems

NASA Astrophysics Data System (ADS)

Eichhubl, P.; Hooker, J. N.

2013-12-01

Reactivation of existing fractures is a fundamental process of brittle failure that controls the nucleation of earthquake ruptures, propagation and linkage of hydraulic fractures in oil and gas production, and the evolution of fault and fracture networks and thus of fluid and heat transport in the upper crust. At depths below 2-3 km, and frequently shallower, brittle processes of fracture growth, linkage, and reactivation compete with chemical processes of fracture sealing by mineral precipitation, with precipitation rates similar to fracture opening rates. We recently found rates of fracture opening in tectonically quiescent settings of 10-20 μm/m.y., rates similar to euhedral quartz precipitation under these conditions. The tendency of existing partially or completely cemented fractures to reactivate will vary depending on strain rate, mineral precipitation kinetics, strength contrast between host rock and fracture cement, stress conditions, degree of fracture infill, and fracture network geometry. Natural fractures in quartzite of the Cambrian Eriboll Formation, NW Scotland, exhibit a complex history of fracture formation and reactivation, with reactivation involving both repeated crack-seal opening-mode failure and shear failure of fractures that formed in opening mode. Fractures are partially to completely sealed with crack-seal or euhedral quartz cement or quartz cement fragmented by shear reactivation. Degree of cementation controls the tendency of fractures for later shear reactivation, to interact elastically with adjacent open fractures, and their intersection behavior. Using kinematic, dynamic, and diagenetic criteria, we determine the sequence of opening-mode fracture formation and later shear reactivation. We find that sheared fracture systems of similar orientation display spatially varying sense of slip We attribute these inconsistent directions of shear reactivation to 1) a heterogeneous stress field in this highly fractured rock unit and 2

Episodic fluid expulsion and fluid pathways during high-pressure dehydration of serpentinite

NASA Astrophysics Data System (ADS)

Padrón-Navarta, J.; Garrido, C. J.; López Sánchez-Vizcaíno, V.; Gómez-Pugnaire, M.; Tommasi, A.; Marchesi, C.

2011-12-01

Our understanding of subduction zone processes is tightly connected to our knowledge of the cycling of volatiles in the Earth, namely the loci of devolatilization reactions and the fluid migration mechanism. The exact nature of fluid pathways at high-pressure conditions is poorly known and still highly speculative. The study of metamorphic terrains that record main dehydration reaction are, thus, an invaluable tool to decipher the mechanism for fluid expulsion. Among other dehydration reactions in subduction zones, the antigorite (Atg) breakdown is rather discontinuous, releases the largest amount of fluids (ca. 9 wt. %) and is considered to have important seismological implications. The antigorite dehydration front in the Cerro del Almirez (Betic Cordillera, Spain) offers, thus, an unique opportunity to investigate the dynamics of fluid expulsion through the study of micro- and macrotextures recorded in the prograde assemblage (chlorite harzburgite). Chl-harzburgites show two textures interspersed in decameter-sized domains: granoblastic and spinifex-like. Both were formed under similar P-T conditions (~1.6-1.9 GPa and 680-710°C)). We ascribe the change in texture to shifts of the growth rate due to temporal and spatial fluctuations of the affinity of the Atg-breakdown reaction. These fluctuations are driven by cyclic variations of the excess fluid pressure which are ultimately controlled by the hydrodynamics of deserpentinization fluid expulsion. Crystallization at a low affinity of the reaction, correspondig to the granoblastic texture, may be attained if fluids are slowly drained out from the dehydration front. During the advancement of the dehydration front, overpressured domains are left behind preserving highly metastable Atg-serpentinite domains. Brittle failure results in a sudden drop of the fluid pressure, and a displacement of Atg equilibrium towards the prograde products that crystallizes at a high affinity of the reaction (spinifex-like texture

Modeling the Proterozoic Basement's Effective Stress Field, Assessing Fault Reactivation Potential Related to Increased Fluid Pressures, and Improved 3D Structural Interpretation of Faulting within Wellington and Anson-Bates Fields, Sumner County, Kansas

NASA Astrophysics Data System (ADS)

Keast, R. T.; Lacroix, B.; Raef, A. E.; Adam, C.; Bidgoli, T. S.; Leclere, H.; Daniel, G.

2017-12-01

South-central Kansas has experienced an increase in seismic activity within the Proterozoic basement. Since 2013, United States Geological Survey (USGS) seismograph stations have recorded 3414 earthquakes. Fluid pressure increases associated with recent high-rate wastewater injection into the dolomitic Arbuckle disposal zone is the hypothesized cause of reactivation of the faulted study region's Proterozoic basement. Although the magnitude of the pressure change required for reactivation of these faults is likely low given failure equilibrium conditions in the midcontinent, heterogeneities in the basement could allow for a range of fluid pressure changes associated with injection. This research aims to quantify the fluid pressure changes responsible for fault reactivation of the Proterozoic basement. To address this issue, we use 103 focal mechanisms and 3,414 seismic events, from the USGS catalog, within an area encompassing 4,000 km2. Three major fault populations have been identified using the dense seismicity and focal mechanism datasets. Win-Tensor paleostress reconstruction software was used to identify effective stress ratios, R = (σ'1/σ'3), and stress tensors for twelve 22 km by 17 km grid squares covering the study area. One fault population strikes parallel with the Nemaha Ridge basement structure ( 030˚). Another reoccurring fault population is oriented 310˚, closely parallel to the Central Kansas Uplift, a subtle anticlinal structure subjected to repeated movement during the Paleozoic. The third population of faults is parallel to the regional maximum compressive stress oriented 265˚ as determined by previous researchers using borehole image logs and shear wave anisotropy. A 3D stress modeling Matlab script was used to analyze fault reactivation potential based on results obtained from Win-Tensor to better understand fault orientations and their susceptibility to reactivation related to pore fluid pressure increases. In addition, the orientations

Pore fluid pressure and the seismic cycle

NASA Astrophysics Data System (ADS)

French, M. E.; Zhu, W.; Hirth, G.; Belzer, B.

2017-12-01

In the brittle crust, the critical shear stress required for fault slip decreases with increasing pore fluid pressures according to the effective stress criterion. As a result, higher pore fluid pressures are thought to promote fault slip and seismogenesis, consistent with observations that increasing fluid pressure as a result of wastewater injection is correlated with increased seismicity. On the other hand, elevated pore fluid pressure is also proposed to promote slow stable failure rather than seismicity along some fault zones, including during slow slip in subduction zones. Here we review recent experimental evidence for the roles that pore fluid pressure and the effective stress play in controlling fault slip behavior. Using two sets of experiments on serpentine fault gouge, we show that increasing fluid pressure does decrease the shear stress for reactivation under brittle conditions. However, under semi-brittle conditions as expected near the base of the seismogenic zone, high pore fluid pressures are much less effective at reducing the shear stress of reactivation even though deformation is localized and frictional. We use an additional study on serpentinite to show that cohesive fault rocks, potentially the product of healing and cementation, experience an increase in fracture energy during faulting as fluid pressures approach lithostatic, which can lead to more stable failure. Structural observations show that the increased fracture energy is associated with a greater intensity of transgranular fracturing and delocalization of deformation. Experiments on several lithologies indicate that the stabilizing effect of fluid pressure occurs independent of rock composition and hydraulic properties. Thus, high pore fluid pressures have the potential to either enhance seismicity or promote stable faulting depending on pressure, temperature, and fluid pressure conditions. Together, the results of these studies indicate that pore fluid pressure promotes

Microstructures Indicate Large Influence of Temperature and Fluid Pressure on the Reactivation of the Alpine Fault, New Zealand

NASA Astrophysics Data System (ADS)

Schuck, B.; Janssen, C.; Schleicher, A.; Toy, V.; Dresen, G.

2017-12-01

The transpressional Alpine Fault within New Zealand's South Island is the major structure that accommodates relative motion between the Pacific and the Australian Plates. It has been intensively studied, because it is late in its 291-year seismic cycle (Cochran et al., 2017; doi: 10.1016/j.epsl.2017.02.026), is likely to generate large (i.e. MW > 8) earthquakes, thus presents the biggest seismic hazard in the region. However, because it is severely misoriented in the present-day stress field for reactivation (Boese et al., 2013; doi: 10.1016/j.epsl.2013.06.030), supra-lithostatic fluid-pressures are required for rupture nucleation. We have analyzed microstructures (SEM and TEM), geochemistry (ICP-OES) and mineralogy (XRD) of outcrop samples of the fault core to investigate the influence of fluids on the geomechanical behavior of the fault. Fluid-related alteration is pervasive within 20 m of the principal slip zone (PSZ) (Sutherland et al., 2012; doi: 10.1130/G33614.1), which is an incohesive, cemented and repeatedly reworked fault gouge mostly consisting of a fine-grained matrix composed of comminuted detrital quartz and feldspar as well as authigenic chlorite and calcite. Authigenic phases seal the PSZ for interseismic cross-fault fluid flow and enable fluid pressure to build-up. Notable, smectite, previously considered to significantly influence propagation of Alpine Fault ruptures, is not present in these samples. Undeformed, euhedral chlorite grains suggest that the processes leading to fault sealing are not only active at greater depths but also close to the surface. The absence of smectite and the presence of undeformed chlorite at very shallow depths can be attributed to the fault's high geothermal gradient of > 120 °C km-1 (Sutherland et al., 2012; doi:10.1038/nature22355), which gives temperature conditions unfavorable for smectite to be stable and fostering chlorite growth. A pervasive network of anastomosing calcite veins in the fault core, depicting

Stability of fault submitted to fluid injections

NASA Astrophysics Data System (ADS)

Brantut, N.; Passelegue, F. X.; Mitchell, T. M.

2017-12-01

Elevated pore pressure can lead to slip reactivation on pre-existing fractures and faults when the coulomb failure point is reached. From a static point of view, the reactivation of fault submitted to a background stress (τ0) is a function of the peak strength of the fault, i.e. the quasi-static effective friction coefficient (µeff). However, this theory is valid only when the entire fault is affected by fluid pressure, which is not the case in nature, and during human induced-seismicity. In this study, we present new results about the influence of the injection rate on the stability of faults. Experiments were conducted on a saw-cut sample of westerly granite. The experimental fault was 8 cm length. Injections were conducted through a 2 mm diameter hole reaching the fault surface. Experiments were conducted at four different order magnitudes fluid pressure injection rates (from 1 MPa/minute to 1 GPa/minute), in a fault system submitted to 50 and 100 MPa confining pressure. Our results show that the peak fluid pressure leading to slip depends on injection rate. The faster the injection rate, the larger the peak fluid pressure leading to instability. Wave velocity surveys across the fault highlighted that decreasing the injection-rate leads to an increase of size of the fluid pressure perturbation. Our result demonstrate that the stability of the fault is not only a function of the fluid pressure requires to reach the failure criterion, but is mainly a function of the ratio between the length of the fault affected by fluid pressure and the total fault length. In addition, we show that the slip rate increases with the background effective stress and with the intensity of the fluid pressure pertubation, i.e. with the excess shear stress acting on the part of the fault pertubated by fluid injection. Our results suggest that crustal fault can be reactivated by local high fluid overpressures. These results could explain the "large" magnitude human-induced earthquakes

Measurement of Reactive Oxygen Species, Reactive Nitrogen Species, and Redox-Dependent Signaling in the Cardiovascular System: A Scientific Statement From the American Heart Association.

PubMed

Griendling, Kathy K; Touyz, Rhian M; Zweier, Jay L; Dikalov, Sergey; Chilian, William; Chen, Yeong-Renn; Harrison, David G; Bhatnagar, Aruni

2016-08-19

Reactive oxygen species and reactive nitrogen species are biological molecules that play important roles in cardiovascular physiology and contribute to disease initiation, progression, and severity. Because of their ephemeral nature and rapid reactivity, these species are difficult to measure directly with high accuracy and precision. In this statement, we review current methods for measuring these species and the secondary products they generate and suggest approaches for measuring redox status, oxidative stress, and the production of individual reactive oxygen and nitrogen species. We discuss the strengths and limitations of different methods and the relative specificity and suitability of these methods for measuring the concentrations of reactive oxygen and reactive nitrogen species in cells, tissues, and biological fluids. We provide specific guidelines, through expert opinion, for choosing reliable and reproducible assays for different experimental and clinical situations. These guidelines are intended to help investigators and clinical researchers avoid experimental error and ensure high-quality measurements of these important biological species. © 2016 American Heart Association, Inc.

Reactive transport of CO2-rich fluids in simulated wellbore interfaces: Experiments and models exploring behaviour on length scales of 1 to 6 m

NASA Astrophysics Data System (ADS)

Wolterbeek, T. K. T.; Raoof, A.; Peach, C. J.; Spiers, C. J.

2016-12-01

Defects present at casing-cement interfaces in wellbores constitute potential pathways for CO2 to migrate from geological storage systems. It is essential to understand how the transport properties of such pathways evolve when penetrated by CO2-rich fluids. While numerous studies have explored this problem at the decimetre length-scale, the 1-10-100 m scales relevant for real wellbores have received little attention. The present work addresses the effects of long-range reactive transport on a length scale of 1-6 m. This is done by means of a combined experimental and modelling study. The experimental work consisted of flow-through tests, performed on cement-filled steel tubes, 1-6 m in length, containing artificially debonded cement-interfaces. Four tests were performed, at 60-80 °C, imposing flow-through of CO2-rich fluid at mean pressures of 10-15 MPa, controlling the pressure difference at 0.12-4.8 MPa, while measuring flow-rate. In the modelling work, we developed a numerical model to explore reactive transport in CO2-exposed defects on a similar length scale. The formulation adopted incorporates fluid flow, advective and diffusive solute transport, and CO2-cement chemical reactions. Our results show that long-range reactive transport strongly affects the permeability evolution of CO2-exposed defects. In the experiments, sample permeability decreased by 2-4 orders, which microstructural observations revealed was associated with downstream precipitation of carbonates, possibly aided by migration of fines. The model simulations show precipitation in initially open defects produces a sharp decrease in flow rate, causing a transition from advection to diffusion-dominated reactive transport. While the modelling results broadly reproduce the experimental observations, it is further demonstrated that non-uniformity in initial defect aperture has a profound impact on self-sealing behaviour and system permeability evolution on the metre scale. The implication is that

Broadband and High power Reactive Jamming Resilient Wireless Communication

DTIC Science & Technology

2017-10-21

Broadband and High -power Reactive Jamming Resilient Wireless Communication The views, opinions and/or findings contained in this report are those of... available in extremely hostile environments, where FHSS and DSSS are completely defeated by a broadband and high -power reactive jammer. b. Wireless...SECURITY CLASSIFICATION OF: 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 13. SUPPLEMENTARY NOTES 12. DISTRIBUTION AVAILIBILITY STATEMENT 6. AUTHORS

HIGH REACTIVITY SORBENTS FOR SO2 CONTROL

EPA Science Inventory

The paper discusses studies, relating to air pollution control from coal-fired utility boilers, that show that the primary variable affecting sorbent reactivity at high temperature or at low temperature with water droplets is surface area. For the development of high surface area...

High tidal volume ventilation induces NOS2 and impairs cAMP- dependent air space fluid clearance.

PubMed

Frank, James A; Pittet, Jean-Francois; Lee, Hyon; Godzich, Micaela; Matthay, Michael A

2003-05-01

Tidal volume reduction during mechanical ventilation reduces mortality in patients with acute lung injury and the acute respiratory distress syndrome. To determine the mechanisms underlying the protective effect of low tidal volume ventilation, we studied the time course and reversibility of ventilator-induced changes in permeability and distal air space edema fluid clearance in a rat model of ventilator-induced lung injury. Anesthetized rats were ventilated with a high tidal volume (30 ml/kg) or with a high tidal volume followed by ventilation with a low tidal volume of 6 ml/kg. Endothelial and epithelial protein permeability were significantly increased after high tidal volume ventilation but returned to baseline levels when tidal volume was reduced. The basal distal air space fluid clearance (AFC) rate decreased by 43% (P < 0.05) after 1 h of high tidal volume but returned to the preventilation rate 2 h after tidal volume was reduced. Not all of the effects of high tidal volume ventilation were reversible. The cAMP-dependent AFC rate after 1 h of 30 ml/kg ventilation was significantly reduced and was not restored when tidal volume was reduced. High tidal volume ventilation also increased lung inducible nitric oxide synthase (NOS2) expression and air space total nitrite at 3 h. Inhibition of NOS2 activity preserved cAMP-dependent AFC. Because air space edema fluid inactivates surfactant and reduces ventilated lung volume, the reduction of cAMP-dependent AFC by reactive nitrogen species may be an important mechanism of clinical ventilator-associated lung injury.

Reactive flash volatilization of fluid fuels

DOEpatents

Schmidt, Lanny D.; Dauenhauer, Paul J.; Dreyer, Bradon J.; Salge, James R.

2013-01-08

The invention provides methods for the production of synthesis gas. More particularly, various embodiments of the invention relate to systems and methods for volatilizing fluid fuel to produce synthesis gas by using a metal catalyst on a solid support matrix.

Safe Disposal of Highly Reactive Chemicals.

ERIC Educational Resources Information Center

Lunn, George; Sansone, Eric B.

1994-01-01

Provides specific procedures for the disposal of a variety of highly reactive chemicals and reports the results of a study of their safe disposal. Disposal of some problematic sulfur-containing compounds are included. Procedures are based on a combination of literature review and author development. (LZ)

High-speed cylindrical collapse of two perfect fluids

NASA Astrophysics Data System (ADS)

Sharif, M.; Ahmad, Zahid

2007-09-01

In this paper, the study of the gravitational collapse of cylindrically distributed two perfect fluid system has been carried out. It is assumed that the collapsing speeds of the two fluids are very large. We explore this condition by using the high-speed approximation scheme. There arise two cases, i.e., bounded and vanishing of the ratios of the pressures with densities of two fluids given by c s , d s . It is shown that the high-speed approximation scheme breaks down by non-zero pressures p 1, p 2 when c s , d s are bounded below by some positive constants. The failure of the high-speed approximation scheme at some particular time of the gravitational collapse suggests the uncertainty on the evolution at and after this time. In the bounded case, the naked singularity formation seems to be impossible for the cylindrical two perfect fluids. For the vanishing case, if a linear equation of state is used, the high-speed collapse does not break down by the effects of the pressures and consequently a naked singularity forms. This work provides the generalisation of the results already given by Nakao and Morisawa (Prog Theor Phys 113:73, 2005) for the perfect fluid.

Dark Solitons in High Velocity Waveguide Polariton Fluids.

PubMed

Walker, P M; Tinkler, L; Royall, B; Skryabin, D V; Farrer, I; Ritchie, D A; Skolnick, M S; Krizhanovskii, D N

2017-09-01

We study exciton-polariton nonlinear optical fluids in the high momentum waveguide regime for the first time. We demonstrate the formation of dark solitons with the expected dependence of width on fluid density for both main classes of soliton-forming fluid defects. The results are well described by numerical modeling of the fluid propagation. We deduce a continuous wave nonlinearity more than ten times that on picosecond time scales, arising due to interaction with the exciton reservoir.

Fluids in crustal deformation: Fluid flow, fluid-rock interactions, rheology, melting and resources

NASA Astrophysics Data System (ADS)

Lacombe, Olivier; Rolland, Yann

2016-11-01

Fluids exert a first-order control on the structural, petrological and rheological evolution of the continental crust. Fluids interact with rocks from the earliest stages of sedimentation and diagenesis in basins until these rocks are deformed and/or buried and metamorphosed in orogens, then possibly exhumed. Fluid-rock interactions lead to the evolution of rock physical properties and rock strength. Fractures and faults are preferred pathways for fluids, and in turn physical and chemical interactions between fluid flow and tectonic structures, such as fault zones, strongly influence the mechanical behaviour of the crust at different space and time scales. Fluid (over)pressure is associated with a variety of geological phenomena, such as seismic cycle in various P-T conditions, hydrofracturing (including formation of sub-horizontal, bedding-parallel veins), fault (re)activation or gravitational sliding of rocks, among others. Fluid (over)pressure is a governing factor for the evolution of permeability and porosity of rocks and controls the generation, maturation and migration of economic fluids like hydrocarbons or ore forming hydrothermal fluids, and is therefore a key parameter in reservoir studies and basin modeling. Fluids may also help the crust partially melt, and in turn the resulting melt may dramatically change the rheology of the crust.

Relationships between Induced Seismicity and Fluid Injection: Development of Strategies to Manage Injection

NASA Astrophysics Data System (ADS)

Eichhubl, Peter; Frohlich, Cliff; Gale, Julia; Olson, Jon; Fan, Zhiqiang; Gono, Valerie

2014-05-01

Induced seismicity during or following the subsurface injection of waste fluids such as well stimulation flow back and production fluids has recently received heightened public and industry attention. It is understood that induced seismicity occurs by reactivation of existing faults that are generally present in the injection intervals. We seek to address the question why fluid injection triggers earthquakes in some areas and not in others, with the aim toward improved injection methods that optimize injection volume and cost while avoiding induced seismicity. A GIS database has been built of natural and induced earthquakes in four hydrocarbon-producing basins: the Fort Worth Basin, South Texas, East Texas/Louisiana, and the Williston Basin. These areas are associated with disposal from the Barnett, Eagle Ford, Bakken, and Haynesville Shales respectively. In each region we analyzed data that were been collected using temporary seismographs of the National Science Foundation's USArray Transportable Array. Injection well locations, formations, histories, and volumes are also mapped using public and licensed datasets. Faults are mapped at a range of scales for selected areas that show different levels of seismic activity, and scaling relationships used to extrapolate between the seismic and wellbore scale. Reactivation potential of these faults is assessed using fault occurrence, and in-situ stress conditions, identifying areas of high and low fault reactivation potential. A correlation analysis between fault reactivation potential, induced seismicity, and fluid injection will use spatial statistics to quantify the probability of seismic fault reactivation for a given injection pressure in the studied reservoirs. The limiting conditions inducing fault reactivation will be compared to actual injection parameters (volume, rate, injection duration and frequency) where available. The objective of this project is a statistical reservoir- to basin-scale assessment of fault

Generation of high reactive fluids by rapid clinopyroxene-seawater interaction: An experimental study at 425 °C, 40 and 100 MPa

NASA Astrophysics Data System (ADS)

Beermann, Oliver; Garbe-Schönberg, Dieter; Schächinger, Steffen; Arzi, Lisa; Holzheid, Astrid

2014-05-01

Submarine hydrothermalism with extensive alteration of oceanic crust is a major process governing energy and mass fluxes from Earth's interior into the oceans. Recent investigations revealed high element fluxes discharging in particular from the generally brittle deformed slow and ultra-slow spreading Mid-Atlantic Ridge (MAR) [1, 2, 3]. This suggests that seawater access to unaltered rocks along juvenile fault systems of the MAR may create hydrothermalism with high fluid and high element fluxes. For example hydrothermal venting at 5° S MAR [4, 5] intensified after a volcano-tectonic event in 2002 [5] and vent fluids constantly emanate here in ~3000 m bsl (~30 MPa) at extreme temperatures above 407 °C [2, 5, 6] and contain high concentrations of transition metals and rare earth elements (REE) [2]. However, geochemical models on mass transfer between oceanic lithosphere and ocean are based upon time integrated mass balance between vent fluid and host rock geochemistry [e.g., 7, 8, 9]. But, none of these models provide estimates for early-stage high-temperature hydrothermalism with unaltered host-rocks as it is evident from the 5°S MAR hydrothermal system. In order to unravel the temporal evolution on element mass transfer between seawater fluid and ocean lithosphere during high-temperature hydrothermalism we started a systematic time-resolved experimental study on seawater-rock interaction processes at variable water-to-rock mass ratios (w/r-ratios). Mixtures of 125-500 µm-sized clinopyroxene (Cpx) and plagioclase (Plag) grains prepared from unaltered gabbro (Atlantis Massif, 30°N MAR, IODP expedition 305, Site U1309D, core sample R211, 1020 m bsf) reacted with two fluid types of similar chlorinity, natural bottom seawater or synthetic 3.2 wt.% NaCl(aq), at 425 °C, 400 and 1000 bar and at w/r ratios from 0.5 to 10 and run durations from 3 to 720 hours. Solid products were analyzed by SEM and XRD, and fluid products were analyzed by ICP-MS and ICP-OES. In all

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

PubMed Central

Stadie, Nicholas P.; Callini, Elsa; Mauron, Philippe; Borgschulte, Andreas; Züttel, Andreas

2015-01-01

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. Herein, nitrogen is presented as a novel supercritical drying fluid for specialized applications such as in the processing of reactive porous materials, where carbon dioxide and other fluids are not appropriate due to their higher chemical reactivity. Nitrogen exhibits similar physical properties in the near-critical region of its phase diagram as compared to carbon dioxide: a widely tunable density up to ~1 g ml-1, modest critical pressure (3.4 MPa), and small molecular diameter of ~3.6 Å. The key to achieving a high solvation power of nitrogen is to apply a processing temperature in the range of 80-150 K, where the density of nitrogen is an order of magnitude higher than at similar pressures near ambient temperature. The detailed solvation properties of nitrogen, and especially its selectivity, across a wide range of common target species of extraction still require further investigation. Herein we describe a protocol for the supercritical nitrogen processing of porous magnesium borohydride. PMID:26066492

Thermal analysis of a reactive generalized Couette flow of power law fluids between concentric cylindrical pipes

NASA Astrophysics Data System (ADS)

Makinde, O. D.

2014-12-01

In this paper, the steady generalized axial Couette flow of Ostwald-de Waele power law reactive fluids between concentric cylindrical pipes is investigated. It is assumed that the outer cylinder is stationary and exchanges heat with the ambient surrounding following Newton's law of cooling, while the inner cylinder with isothermal surface is set in motion in the axial direction. The model nonlinear differential equations for the momentum and energy balance are obtained and tackled numerically using the shooting method coupled with the Runge-Kutta-Fehlberg integration technique. The effects of various embedded thermophysical parameters on the velocity and temperature fields including skin friction, Nusselt number and thermal criticality conditions are presented graphically and discussed quantitatively.

Heat transfer fluids containing nanoparticles

DOEpatents

Singh, Dileep; Routbort, Jules; Routbort, A.J.; Yu, Wenhua; Timofeeva, Elena; Smith, David S.; France, David M.

2016-05-17

A nanofluid of a base heat transfer fluid and a plurality of ceramic nanoparticles suspended throughout the base heat transfer fluid applicable to commercial and industrial heat transfer applications. The nanofluid is stable, non-reactive and exhibits enhanced heat transfer properties relative to the base heat transfer fluid, with only minimal increases in pumping power required relative to the base heat transfer fluid. In a particular embodiment, the plurality of ceramic nanoparticles comprise silicon carbide and the base heat transfer fluid comprises water and water and ethylene glycol mixtures.

Rotational viscometer for high-pressure high-temperature fluids

DOEpatents

Carr, Kenneth R.

1985-01-01

The invention is a novel rotational viscometer which is well adapted for use with fluids at high temperatures and/or pressures. In one embodiment, the viscometer includes a substantially non-magnetic tube having a closed end and having an open end in communication with a fluid whose viscosity is to be determined. An annular drive magnet is mounted for rotation about the tube. The tube encompasses and supports a rotatable shaft assembly which carries a rotor, or bob, for insertion in the fluid. Affixed to the shaft are (a) a second magnet which is magnetically coupled to the drive magnet and (b) a third magnet. In a typical operation, the drive magnet is rotated to turn the shaft assembly while the shaft rotor is immersed in the fluid. The viscous drag on the rotor causes the shaft assembly to lag the rotation of the drive magnet by an amount which is a function of the amount of viscous drag. A first magnetic pickup generates a waveform whose phase is a function of the angular position of the drive magnet. A second magnetic pickup generates a waveform whose phase is a function of the angular position of the third magnet. An output is generated indicative of the phase difference between the two waveforms.

[VDRL and FTA-ABS reactivity in cerebrospinal fluid: our experience].

PubMed

García-Rodríguez, J A; Martín-Sánchez, A M; Canut, A; García-García, L; Cacho, J

1990-01-01

The reactivity of 194 samples of CSF against VDRL and FTA-ABS was studied in patients attending the Clinical Hospital in Salamanca over a five years period. This laboratory was asked to rule out an etiology of syphilis. Twelve samples of CSF proved to be reactive (6.2%) against VDRL and/or FTA-ABS. Seven of these corresponded to six adults diagnosed as suffering from neurosyphilis and one to an infant with early congenital syphilis without neurological alterations; these had in common the presence of active syphilis and a reactive FTA-ABS in serum. In the CSF of the six cases of neurosyphilis, VDRL was reactive in two patients (33.3%) and FTA-ABS in five (83.3%). One minimally reactive VDRL and four FTA-ABS were detected in the remaining five patients, with no known previous history of syphilis, that were suffering from different neurological alterations and that had a nonreactive FTA-ABS in serum. The results obtained in this study point to inappropriate use in CSF of VDRL and FTA-ABS to exclude neurosyphilis in our hospital since only 3.6% of the CSF studied corresponded to patients diagnosed as suffering from neurosyphilis and also to the need for improving the criteria for patient selection.

A reactive transport modelling approach to assess the leaching potential of hydraulic fracturing fluids associated with coal seam gas extraction

NASA Astrophysics Data System (ADS)

Mallants, Dirk; Simunek, Jirka; Gerke, Kirill

2015-04-01

Coal Seam Gas production generates large volumes of "produced" water that may contain compounds originating from the use of hydraulic fracturing fluids. Such produced water also contains elevated concentrations of naturally occurring inorganic and organic compounds, and usually has a high salinity. Leaching of produced water from storage ponds may occur as a result of flooding or containment failure. Some produced water is used for irrigation of specific crops tolerant to elevated salt levels. These chemicals may potentially contaminate soil, shallow groundwater, and groundwater, as well as receiving surface waters. This paper presents an application of scenario modelling using the reactive transport model for variably-saturated media HP1 (coupled HYDRUS-1D and PHREEQC). We evaluate the fate of hydraulic fracturing chemicals and naturally occurring chemicals in soil as a result of unintentional release from storage ponds or when produced water from Coal Seam Gas operations is used in irrigation practices. We present a review of exposure pathways and relevant hydro-bio-geo-chemical processes, a collation of physico-chemical properties of organic/inorganic contaminants as input to a set of generic simulations of transport and attenuation in variably saturated soil profiles. We demonstrate the ability to model the coupled processes of flow and transport in soil of contaminants associated with hydraulic fracturing fluids and naturally occurring contaminants.

Chalk-calcite-microfluidic experiments: construction and flooding of microsystems with reactive fluids

NASA Astrophysics Data System (ADS)

Neuville, Amélie; Thuy Luu, Thi; Dysthe, Dag Kristian; Vinningland, Jan Ludvig; Hiorth, Aksel

2015-04-01

Direct in situ observation of the pore structure changes that occur when chalk is flooded with brines could resolve many of the open questions that remain about the interactions between mineralogical alterations and oil-liberating mechanisms. Experiments on core scale and field tests that have been carried out the last decade have clearly shown that water chemistry affects the final oil recovery. However, there is generally no consensus in the scientific community of why additional oil is released. In this work, our aim is to focus on in-situ observations of single phase flow and interactions at the pore scale. To do so, we create several types of custom-made microsystems with chalk and calcite crystals. We then do experiments with reacting fluids in these microsystems. During these experiments, we realize in-situ observations (geometrical characteristics, reaction rate) using microsopy techniques (white light vertical/phase shift interferometric microscopy, and classical microscopy), and show how they vary as function as the water chemistry. In simple systems made of calcite, we obtain reactive rates that are coherent with the litterature and with numerical simulations based on Lattice-Boltzmann methods.

Measurement of K-27, an oxime-type cholinesterase reactivator by high-performance liquid chromatography with electrochemical detection from different biological samples.

PubMed

Gyenge, Melinda; Kalász, Huba; Petroianu, George A; Laufer, Rudolf; Kuca, Kamil; Tekes, Kornélia

2007-08-17

K-27 is a bisquaternary asymmetric pyridinium aldoxime-type cholinesterase reactivator of use in the treatment of poisoning with organophosphorous esterase inhibitors. A sensitive, simple and reliable reverse-phase high-performance liquid chromatographic method with electrochemical detection was developed for the measurement of K-27 concentrations in rat brain, cerebrospinal fluid, serum and urine samples. Male Wistar rats were treated intramuscularly with K-27 and the samples were collected 60 min later. Separation was carried out on an octadecyl silica stationary phase and a disodium phosphate solution (pH 3.7) containing citric acid, octane sulphonic acid and acetonitrile served as mobile phase. Measurements were carried out at 30 degrees C at E(ox) 0.65 V. The calibration curve was linear through the range of 10-250 ng/mL. Accuracy, precision and the limit of detection calculated were satisfactory according to internationally accepted criteria. Limit of quantitation was 10 ng/mL. The method developed is reliable and sensitive enough for monitoring K-27 levels from different biological samples including as little as 10 microL of cerebrospinal fluid. The method--with slight modification in the composition of the mobile phase--can be used to measure a wide range of other related pyridinium aldoxime-type cholinesterase reactivators.

Fluid involvement in normal faulting

NASA Astrophysics Data System (ADS)

Sibson, Richard H.

2000-04-01

Evidence of fluid interaction with normal faults comes from their varied role as flow barriers or conduits in hydrocarbon basins and as hosting structures for hydrothermal mineralisation, and from fault-rock assemblages in exhumed footwalls of steep active normal faults and metamorphic core complexes. These last suggest involvement of predominantly aqueous fluids over a broad depth range, with implications for fault shear resistance and the mechanics of normal fault reactivation. A general downwards progression in fault rock assemblages (high-level breccia-gouge (often clay-rich) → cataclasites → phyllonites → mylonite → mylonitic gneiss with the onset of greenschist phyllonites occurring near the base of the seismogenic crust) is inferred for normal fault zones developed in quartzo-feldspathic continental crust. Fluid inclusion studies in hydrothermal veining from some footwall assemblages suggest a transition from hydrostatic to suprahydrostatic fluid pressures over the depth range 3-5 km, with some evidence for near-lithostatic to hydrostatic pressure cycling towards the base of the seismogenic zone in the phyllonitic assemblages. Development of fault-fracture meshes through mixed-mode brittle failure in rock-masses with strong competence layering is promoted by low effective stress in the absence of thoroughgoing cohesionless faults that are favourably oriented for reactivation. Meshes may develop around normal faults in the near-surface under hydrostatic fluid pressures to depths determined by rock tensile strength, and at greater depths in overpressured portions of normal fault zones and at stress heterogeneities, especially dilational jogs. Overpressures localised within developing normal fault zones also determine the extent to which they may reutilise existing discontinuities (for example, low-angle thrust faults). Brittle failure mode plots demonstrate that reactivation of existing low-angle faults under vertical σ1 trajectories is only likely if

Rotational viscometer for high-pressure, high-temperature fluids

DOEpatents

Carr, K.R.

1983-06-06

The invention is a novel rotational viscometer which is well adapted for use with fluids at high temperatures and/or pressures. In one embodiment, the viscometer include a substantially non-magnetic tube having a closed end and having an open end in communication with a fluid whose viscosity is to be determined. An annular drive magnet is mounted for rotation about the tube. The tube encompasses and supports a rotatable shaft assembly which carries a rotor, or bob, for insertion in the fluid. Affixed to the shaft are (a) a second magnet which is magnetically coupled to the drive magnet and (b) a third magnet. In a typical operation, the drive magnet is rotated to turn the shaft assembly while the shaft rotor is immersed in the fluid. The viscous drag on the rotor causes the shaft assembly to lag the rotation of the drive magnet by an amount which is a function of the amount of viscous drag. A first magnetic pickup generates a waveform whose phase is a function of the angular position of the drive magnet. A second magnetic pickup generates a waveform whose phase is a function of the angular position of the third magnet. Means are provided to generate an output indicative of the phase difference between the two waveforms. The viscometer is comparatively simple, inexpensive, rugged, and does not require shaft seals.

ERPs evidence for the relationship between fluid intelligence and cognitive control.

PubMed

Lu, Di; Zhang, Haoyun; Kang, Chunyan; Guo, Taomei

2016-04-13

The relationship between two components of cognitive control, that is, proactive control and reactive control, and fluid intelligence was investigated by measuring 75 participants' event-related potentials in the AX version of the continuous performance test. The results showed that the mean amplitudes of N2 associated with the two components of cognitive control are highly correlated with fluid intelligence. Specifically, a larger N2 was shown in participants with higher fluid intelligence scores. No significant correlation was found in the peak latencies of the N2 and fluid intelligence. These results enrich our understanding of the relationship between cognitive control and fluid intelligence by using the N2 component as an index and also indicate that cognitive control may be a component of intelligence.

Tutorial: Reactive high power impulse magnetron sputtering (R-HiPIMS)

NASA Astrophysics Data System (ADS)

Anders, André

2017-05-01

High Power Impulse Magnetron Sputtering (HiPIMS) is a coating technology that combines magnetron sputtering with pulsed power concepts. By applying power in pulses of high amplitude and a relatively low duty cycle, large fractions of sputtered atoms and near-target gases are ionized. In contrast to conventional magnetron sputtering, HiPIMS is characterized by self-sputtering or repeated gas recycling for high and low sputter yield materials, respectively, and both for most intermediate materials. The dense plasma in front of the target has the dual function of sustaining the discharge and providing plasma-assistance to film growth, affecting the microstructure of growing films. Many technologically interesting thin films are compound films, which are composed of one or more metals and a reactive gas, most often oxygen or nitrogen. When reactive gas is added, non-trivial consequences arise for the system because the target may become "poisoned," i.e., a compound layer forms on the target surface affecting the sputtering yield and the yield of secondary electron emission and thereby all other parameters. It is emphasized that the target state depends not only on the reactive gas' partial pressure (balanced via gas flow and pumping) but also on the ion flux to the target, which can be controlled by pulse parameters. This is a critical technological opportunity for reactive HiPIMS (R-HiPIMS). The scope of this tutorial is focused on plasma processes and mechanisms of operation and only briefly touches upon film properties. It introduces R-HiPIMS in a systematic, step-by-step approach by covering sputtering, magnetron sputtering, reactive magnetron sputtering, pulsed reactive magnetron sputtering, HiPIMS, and finally R-HiPIMS. The tutorial is concluded by considering variations of R-HiPIMS known as modulated pulsed power magnetron sputtering and deep-oscillation magnetron sputtering and combinations of R-HiPIMS with superimposed dc magnetron sputtering.

Fluid Lensing, Applications to High-Resolution 3D Subaqueous Imaging & Automated Remote Biosphere Assessment from Airborne and Space-borne Platforms

NASA Astrophysics Data System (ADS)

Chirayath, V.

2014-12-01

Fluid Lensing is a theoretical model and algorithm I present for fluid-optical interactions in turbulent flows as well as two-fluid surface boundaries that, when coupled with an unique computer vision and image-processing pipeline, may be used to significantly enhance the angular resolution of a remote sensing optical system with applicability to high-resolution 3D imaging of subaqueous regions and through turbulent fluid flows. This novel remote sensing technology has recently been implemented on a quadcopter-based UAS for imaging shallow benthic systems to create the first dataset of a biosphere with unprecedented sub-cm-level imagery in 3D over areas as large as 15 square kilometers. Perturbed two-fluid boundaries with different refractive indices, such as the surface between the ocean and air, may be exploited for use as lensing elements for imaging targets on either side of the interface with enhanced angular resolution. I present theoretical developments behind Fluid Lensing and experimental results from its recent implementation for the Reactive Reefs project to image shallow reef ecosystems at cm scales. Preliminary results from petabyte-scale aerial survey efforts using Fluid Lensing to image at-risk coral reefs in American Samoa (August, 2013) show broad applicability to large-scale automated species identification, morphology studies and reef ecosystem characterization for shallow marine environments and terrestrial biospheres, of crucial importance to understanding climate change's impact on coastal zones, global oxygen production and carbon sequestration.

Hall effects on unsteady MHD reactive flow of second grade fluid through porous medium in a rotating parallel plate channel

NASA Astrophysics Data System (ADS)

Krishna, M. Veera; Swarnalathamma, B. V.

2017-07-01

We considered the transient MHD flow of a reactive second grade fluid through porous medium between two infinitely long horizontal parallel plates when one of the plate is set into uniform accelerated motion in the presence of a uniform transverse magnetic field under Arrhenius reaction rate. The governing equations are solved by Laplace transform technique. The effects of the pertinent parameters on the velocity, temperature are discussed in detail. The shear stress and Nusselt number at the plates are also obtained analytically and computationally discussed with reference to governing parameters.

Implementing fluid dynamics obtained from GeoPET in reactive transport models

NASA Astrophysics Data System (ADS)

Lippmann-Pipke, Johanna; Eichelbaum, Sebastian; Kulenkampff, Johannes

2016-04-01

Flow and transport simulations in geomaterials are commonly conducted on high-resolution tomograms (μCT) of the pore structure or stochastic models that are calibrated with measured integral quantities, like break through curves (BTC). Yet, there existed virtually no method for experimental verification of the simulated velocity distribution results. Positron emission tomography (PET) has unrivaled sensitivity and robustness for non-destructive, quantitative, spatio-temporal measurement of tracer concentrations in body tissue. In the past decade, we empowered PET for its applicability in opaque/geological media - GeoPET (Kulenkampff et al.; Kulenkampff et al., 2008; Zakhnini et al., 2013) and have developed detailed correction schemes to bring the images into sharp focus. Thereby it is the appropriate method for experimental verification and calibration of computer simulations of pore-scale transport by means of the observed propagation of a tracer pulse, c_PET(x,y,z,t). In parallel, we aimed at deriving velocity and porosity distributions directly from our concentration time series of fluid flow processes in geomaterials. This would allow us to directly benefit from lab scale observations and to parameterize respective numerical transport models. For this we have developed a robust spatiotemporal (3D+t) parameter extraction algorithm. Here, we will present its functionality, and demonstrate the use of obtained velocity distributions in finite element simulations of reactive transport processes on drill core scale. Kulenkampff, J., Gruendig, M., Zakhnini, A., Gerasch, R., and Lippmann-Pipke, J.: Process tomography of diffusion with PET for evaluating anisotropy and heterogeneity, Clay Minerals, in press. Kulenkampff, J., Gründig, M., Richter, M., and Enzmann, F.: Evaluation of positron emission tomography for visualisation of migration processes in geomaterials, Physics and Chemistry of the Earth, 33, 937-942, 2008. Zakhnini, A., Kulenkampff, J., Sauerzapf, S

Role of bedside pancreatic scores and C-reactive protein in predicting pancreatic fluid collections and necrosis.

PubMed

Vinish, Doraiswami Babu; Abishek, Vishnu; Sujatha, K; Arulprakash, S; Solomon, Rajkumar; Ganesh, P

2017-01-01

Acute pancreatitis is a disease with variable outcome; the course of the disease can be modified by early aggressive management in patients with severe pancreatitis. Easily calculable pancreatic scores and investigations can help to triage these patients. We aimed to determine the role of bedside index for severity in acute pancreatitis (BISAP), harmless acute pancreatitis score (HAPS), and systemic inflammatory response syndrome (SIRS) scores on day of admission and C-reactive protein (CRP) at 48 h for predicting the presence of pancreatic fluid collection (PFC) and necrosis on CT scans done at 72 h. Of a total of 114 consecutively seen patients of pancreatitis, 64 with acute pancreatitis were enrolled in the study. All individuals had the pancreatitis predicting scores calculated at the time of admission, CRP at 48 h, and contrast-enhanced computed tomography (CECT) abdomen at 72 h from admission. The study population of 64 (55 male) had a mean (+SD) age of 37.7 ± 13 years. Alcohol was the most common (68.8%) etiology in these patients. Based on CECT, patients were divided into 2 groups; group 1 with 41 patients who had mild pancreatitis and group 2 with 23 patients who had pancreatic fluid collection with or without necrosis (PFCN). PFCN were seen in 19 (29.7%) of patients with 2 or more SIRS criteria, 17 (26.6%) of patients with BISAP score ≥3, and 16 patients (25.0%) with HAPS >0 respectively. All three scores were able to predict PFCN significantly. CRP >150 mg/L was noted in 23 patients and was able to predict the presence of fluid collections (p=0.0002) and pancreatic necrosis (p = 0.0004) on CT. BISAP, HAPS, and SIRS scores and CRP of 150 mg/L all correlated significantly with the occurrence of fluid collections and pancreatic necrosis on CT at 72 h. None of the scores was superior to the other in this respect.

High refractive index nanocomposite fluids for immersion lithography.

PubMed

Bremer, L; Tuinier, R; Jahromi, S

2009-02-17

The concept of using dispersions of nanoparticles as high refractive index fluids in immersion lithography is examined both from a theoretical and experimental point of view. In the theoretical part we show that gelation and demixing can be controlled in high solid dispersions, needed to achieve a high (refractive) index, by using short stabilizing brushes. We considered both fluid-fluid demixing by using statistical thermodynamics and percolation, computed using liquid-state approaches. Whenever demixing or percolation takes place, the nanoparticle dispersion is unsuited for immersion lithography. The minimum thickness of the stabilizer layer of a stable suspension is estimated assuming particles plus steric stabilizer to act as hard spheres with van der Waals attraction between the cores. Since the van der Waals attraction can be related to the optical properties of the particles and dispersion medium, it is also possible to estimate the refractive index that can be attained with composite immersion fluids. Using materials that are known to be highly transparent in the bulk at a wavelength of 193 nm, indices above 1.8 can be attained. Other materials with higher indices are expected to be transparent at 193 nm due to a blue shift of the UV absorption and enable much higher indices. In the experiment, we show that it is possible to prepare suspensions with particles of about 4 nm diameter that increase the refractive index of the continuous phase with 0.2 at a wavelength of 193 nm. The refractive index and density of such dispersions are proportional to the volume fraction of the disperse phase, and it is shown that the refractive index of the composite fluid can be predicted very well from the optical properties of the components. Furthermore, successful imaging experiments were performed through a dispersion of silica nanoparticles. These findings lead to the conclusion that immersion lithography using nanoparticle dispersions is indeed possible.

Crevicular Fluid and Serum Concentrations of Progranulin and High Sensitivity CRP in Chronic Periodontitis and Type 2 Diabetes

PubMed Central

Priyanka, N.; Kumari, Minal; Kalra, Nitish; Arjun, P.; Naik, Savitha B.; Pradeep, A. R.

2013-01-01

Introduction. This study was designed to correlate the serum and gingival crevicular fluid (GCF) levels of progranulin (PGRN) and high sensitivity C-reactive protein (hs CRP) in chronic periodontitis and type 2 diabetes mellitus (DM). Design. PGRN and hs CRP levels were estimated in 3 groups: healthy, chronic periodontitis, and type 2 DM with chronic periodontitis. Results. The mean PGRN and hs CRP concentrations in serum and GCF were the highest for group 3 followed by group 2 and the least in group 1. Conclusion. PGRN and hs CRP may be biomarkers of the inflammatory response in type 2 DM and chronic periodontitis. PMID:24191130

Tutorial: Reactive high power impulse magnetron sputtering (R-HiPIMS)

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

Anders, André

High Power Impulse Magnetron Sputtering (HiPIMS) is a coating technology that combines magnetron sputtering with pulsed power concepts. Furthermore, by applying power in pulses of high amplitude and a relatively low duty cycle, large fractions of sputtered atoms and near-target gases are ionized. In contrast to conventional magnetron sputtering, HiPIMS is characterized by self-sputtering or repeated gas recycling for high and low sputter yield materials, respectively, and both for most intermediate materials. The dense plasma in front of the target has the dual function of sustaining the discharge and providing plasma-assistance to film growth, affecting the microstructure of growing films.more » Many technologically interesting thin films are compound films, which are composed of one or more metals and a reactive gas, most often oxygen or nitrogen. When reactive gas is added, non-trivial consequences arise for the system because the target may become “poisoned,” i.e., a compound layer forms on the target surface affecting the sputtering yield and the yield of secondary electron emission and thereby all other parameters. It is emphasized that the target state depends not only on the reactive gas' partial pressure (balanced via gas flow and pumping) but also on the ion flux to the target, which can be controlled by pulse parameters. This is a critical technological opportunity for reactive HiPIMS (R-HiPIMS). The scope of this tutorial is focused on plasma processes and mechanisms of operation and only briefly touches upon film properties. It introduces R-HiPIMS in a systematic, step-by-step approach by covering sputtering, magnetron sputtering, reactive magnetron sputtering, pulsed reactive magnetron sputtering, HiPIMS, and finally R-HiPIMS. The tutorial is concluded by considering variations of R-HiPIMS known as modulated pulsed power magnetron sputtering and deep-oscillation magnetron sputtering and combinations of R-HiPIMS with superimposed dc magnetron

Tutorial: Reactive high power impulse magnetron sputtering (R-HiPIMS)

DOE PAGES

Anders, André

2017-03-21

High Power Impulse Magnetron Sputtering (HiPIMS) is a coating technology that combines magnetron sputtering with pulsed power concepts. Furthermore, by applying power in pulses of high amplitude and a relatively low duty cycle, large fractions of sputtered atoms and near-target gases are ionized. In contrast to conventional magnetron sputtering, HiPIMS is characterized by self-sputtering or repeated gas recycling for high and low sputter yield materials, respectively, and both for most intermediate materials. The dense plasma in front of the target has the dual function of sustaining the discharge and providing plasma-assistance to film growth, affecting the microstructure of growing films.more » Many technologically interesting thin films are compound films, which are composed of one or more metals and a reactive gas, most often oxygen or nitrogen. When reactive gas is added, non-trivial consequences arise for the system because the target may become “poisoned,” i.e., a compound layer forms on the target surface affecting the sputtering yield and the yield of secondary electron emission and thereby all other parameters. It is emphasized that the target state depends not only on the reactive gas' partial pressure (balanced via gas flow and pumping) but also on the ion flux to the target, which can be controlled by pulse parameters. This is a critical technological opportunity for reactive HiPIMS (R-HiPIMS). The scope of this tutorial is focused on plasma processes and mechanisms of operation and only briefly touches upon film properties. It introduces R-HiPIMS in a systematic, step-by-step approach by covering sputtering, magnetron sputtering, reactive magnetron sputtering, pulsed reactive magnetron sputtering, HiPIMS, and finally R-HiPIMS. The tutorial is concluded by considering variations of R-HiPIMS known as modulated pulsed power magnetron sputtering and deep-oscillation magnetron sputtering and combinations of R-HiPIMS with superimposed dc magnetron

Inside out: Speed-dependent barriers to reactive mixing

NASA Astrophysics Data System (ADS)

Kelley, Douglas; Nevins, Thomas

2015-11-01

Reactive mixing occurs wherever fluid flow and chemical or biological growth interact over time and space. Those interactions often lead to steep gradients in reactant and product concentration, arranged in complex spatial structures that can cause wide variation in the global reaction rate and concentrations. By simultaneously measuring fluid velocity and reaction front locations in laboratory experiments with the Belousov-Zhabotinsky reaction, we find that the barriers defining those structures vary dramatically with speed. In particular, we find that increasing flow speed causes reacted regions to move from vortex edges to vortex cores, thus turning the barriers ``inside out''. This observation has implications for reactive mixing of phytoplankton in global oceans.

Measurements of C-reactive protein in serum and lactate dehydrogenase in serum and synovial fluid of patients with osteoarthritis.

PubMed

Hurter, K; Spreng, D; Rytz, U; Schawalder, P; Ott-Knüsel, F; Schmökel, H

2005-03-01

Diagnosis of osteoarthritis (OA) is based upon the clinical orthopaedic examination and the radiographic assessment, both of which can be non-specific and insensitive in early joint disease. The aim of our study was to investigate if there is an increase in serum levels of C-reactive protein (CRP) in degenerative joint disease (DJD) and if CRP could be used to help diagnose OA. We also wished to investigate whether it was possible to distinguish a joint with clinically and radiographically confirmed OA from a healthy joint by comparing lactate dehydrogenase (LDH) levels within the synovial fluid and the serum. We have shown a difference in synovial LDH levels between diseased and healthy joints (P<0.0001). There was also a significant difference between LDH in arthritic synovial fluid and serum, with no correlation between the values. Despite the fact that the values of our clinical patients tended to be higher than the values of our control group (P=0.05) all measured values were within the normal limits of previous publications. From these data, we conclude that single measurements of serum CRP do not permit detection of OA in clinical patients and that serum LDH is not a reliable marker for osteoarthritis. LDH levels in the synovial fluid could be of diagnostic value for identifying osteoarthritis.

Progressive periodontal disease has a simultaneous incremental elevation of gingival crevicular fluid and serum CRP levels.

PubMed

Pradeep, A R; Manjunath, R G Shiva; Kathariya, Rahul

2010-11-01

Increased C-reactive protein levels have been found in all active inflammations, including periodontitis. This study aims to assess the C-reactive protein levels in periodontal disease progression. Forty-five patients were divided into the following three groups (n=15) based on gingival index, probing pocket depth, and clinical attachment level: healthy (group I), gingivitis (group II), and chronic periodontitis (group III). Gingival crevicular fluid and serum samples were quantified for C-reactive protein using enzyme-linked immunosorbent assay. The mean C-reactive protein concentration in gingival crevicular fluid and serum was found to be highest in group III (1233.33ng/mL for gingival crevicular fluid, 5483.33ng/mL for serum), and least in group I (60 ng/mL and 413 ng/mL for gingival crevicular fluid and serum, respectively) The mean C-reactive protein concentration in group II (453.33ng/mL for gingival crevicular fluid and 3565.33 ng/mL for serum) was found to be intermediate. C-reactive protein levels in gingival crevicular fluid and serum increased proportionately with the severity of periodontal disease. They correlated positively with clinical parameters, including gingival index, probing pocket depth, and clinical attachment level. Thus, it can be considered as a periodontal inflammatory biomarker and deserves further consideration. © 2010 Blackwell Publishing Asia Pty Ltd.

User's Guide of TOUGH2-EGS. A Coupled Geomechanical and Reactive Geochemical Simulator for Fluid and Heat Flow in Enhanced Geothermal Systems Version 1.0

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

Fakcharoenphol, Perapon; Xiong, Yi; Hu, Litang

TOUGH2-EGS is a numerical simulation program coupling geomechanics and chemical reactions for fluid and heat flows in porous media and fractured reservoirs of enhanced geothermal systems. The simulator includes the fully-coupled geomechanical (THM) module, the fully-coupled geochemical (THC) module, and the sequentially coupled reactive geochemistry (THMC) module. The fully-coupled flow-geomechanics model is developed from the linear elastic theory for the thermo-poro-elastic system and is formulated with the mean normal stress as well as pore pressure and temperature. The chemical reaction is sequentially coupled after solution of flow equations, which provides the flow velocity and phase saturation for the solute transportmore » calculation at each time step. In addition, reservoir rock properties, such as porosity and permeability, are subjected to change due to rock deformation and chemical reactions. The relationships between rock properties and geomechanical and chemical effects from poro-elasticity theories and empirical correlations are incorporated into the simulator. This report provides the user with detailed information on both mathematical models and instructions for using TOUGH2-EGS for THM, THC or THMC simulations. The mathematical models include the fluid and heat flow equations, geomechanical equation, reactive geochemistry equations, and discretization methods. Although TOUGH2-EGS has the capability for simulating fluid and heat flows coupled with both geomechanical and chemical effects, it is up to the users to select the specific coupling process, such as THM, THC, or THMC in a simulation. There are several example problems illustrating the applications of this program. These example problems are described in details and their input data are presented. The results demonstrate that this program can be used for field-scale geothermal reservoir simulation with fluid and heat flow, geomechanical effect, and chemical reaction in porous and

Liquid chromatography tandem mass spectrometry determination of selected synthetic cathinones and two piperazines in oral fluid. Cross reactivity study with an on-site immunoassay device.

PubMed

de Castro, Ana; Lendoiro, Elena; Fernández-Vega, Hadriana; Steinmeyer, Stefan; López-Rivadulla, Manuel; Cruz, Angelines

2014-12-29

Since the past few years, several synthetic cathinones and piperazines have been introduced into the drug market to substitute illegal stimulant drugs such as amphetamine and derivatives or cocaine due to their unregulated situation. These emerging drugs are not usually included in routine toxicological analysis. We developed and validated a LC-MS/MS method for the determination of methedrone, methylone, mephedrone, 3,4-methylenedioxypyrovalerone (MDPV), fluoromethcathinone, fluoromethamphetamine, 1-(3-chlorophenyl)piperazine (mCPP) and 3-trifluoromethylphenylpiperazine (TFMPP) in oral fluid. Sample extraction was performed using Strata X cartridges. Chromatographic separation was achieved in 10min using an Atlantis(®) T3 column (100mm×2.1mm, 3μm), and formic acid 0.1% and acetonitrile as mobile phase. The method was satisfactorily validated, including selectivity, linearity (0.2-0.5 to 200ng/mL), limits of detection (0.025-0.1ng/mL) and quantification (0.2-0.5ng/mL), imprecision and accuracy in neat oral fluid (%CV=0.0-12.7% and 84.8-103.6% of target concentration, respectively) and in oral fluid mixed with Quantisal™ buffer (%CV=7.2-10.3% and 80.2-106.5% of target concentration, respectively), matrix effect in neat oral fluid (-11.6 to 399.7%) and in oral fluid with Quantisal™ buffer (-69.9 to 131.2%), extraction recovery (87.9-134.3%) and recovery from the Quantisal™ (79.6-107.7%), dilution integrity (75-99% of target concentration) and stability at different conditions (-14.8 to 30.8% loss). In addition, cross reactivity produced by the studied synthetic cathinones in oral fluid using the Dräger DrugTest 5000 was assessed. All the analytes produced a methamphetamine positive result at high concentrations (100 or 10μg/mL), and fluoromethamphetamine also at low concentration (0.075μg/mL). Copyright © 2014 Elsevier B.V. All rights reserved.

Birth weight, current anthropometric markers, and high sensitivity C-reactive protein in Brazilian school children.

PubMed

Boscaini, Camile; Pellanda, Lucia Campos

2015-01-01

Studies have shown associations of birth weight with increased concentrations of high sensitivity C-reactive protein. This study assessed the relationship between birth weight, anthropometric and metabolic parameters during childhood, and high sensitivity C-reactive protein. A total of 612 Brazilian school children aged 5-13 years were included in the study. High sensitivity C-reactive protein was measured by particle-enhanced immunonephelometry. Nutritional status was assessed by body mass index, waist circumference, and skinfolds. Total cholesterol and fractions, triglycerides, and glucose were measured by enzymatic methods. Insulin sensitivity was determined by the homeostasis model assessment method. Statistical analysis included chi-square test, General Linear Model, and General Linear Model for Gamma Distribution. Body mass index, waist circumference, and skinfolds were directly associated with birth weight (P < 0.001, P = 0.001, and P = 0.015, resp.). Large for gestational age children showed higher high sensitivity C-reactive protein levels (P < 0.001) than small for gestational age. High birth weight is associated with higher levels of high sensitivity C-reactive protein, body mass index, waist circumference, and skinfolds. Large for gestational age altered high sensitivity C-reactive protein and promoted additional risk factor for atherosclerosis in these school children, independent of current nutritional status.

Multiple viral genome search in endolabyrinthic fluids of profoundly deaf patients: possible cytomegalovirus intracochlear reactivation.

PubMed

Di Nardo, W; Cattani, P; Lopizzo, T; Cantore, I; Marchese, M R; Marchetti, S; Scorpecci, A; Giannantonio, S; Parrilla, C; Cianfrone, F; Fadda, G; Paludetti, G

2009-01-01

The cause of about 30% of bilateral sensorineural hearing loss (SNHL) is still unknown. A viral etiology is among the most frequently proposed ones and the supposed diagnosis is only based upon few clinical and laboratory data. The detection of viral presence within a damaged compartment may represent a way to supply interesting data for confirmation of viral etiology and to explain pathogenic mechanisms. The aim of our study was to identify the possible presence of pathogenic viruses in the inner ear extracellular compartment in patients with bilateral severe sensorineural deafness of unknown etiology who underwent cochlear implant surgery. 4 patients, aged from 2 to 7 years and affected by SNHL underwent cochlear implantation surgery and, at the same time, endolabyrinthine fluid sampling. The samples were subsequently sent for viral nucleic acid extraction and polymerase chain reaction (PCR) treatment: multiplex PCR and realtime-PCR were used. In each endolabyrinthine fluid sample, cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella-zoster virus (VZV), herpes simplex virus type 1 and 2 (HSV-1, HSV-2) and enterovirus genomes were searched for. One patient was positive for intracochlear CMV, as confirmed by another base-pair segment PCR. EBV, VZV, HSV and enterovirus were detected in none of the 4 patients. Our finding of CMV genome within the cochlea of a deaf patient without any evidence of acute and prenatal CMV infection suggests its possible role in postnatal inner ear injury through reactivation of latent virus within the cochlea. This hypothesis could also be considered valid for some patients with anti-CMV-IgG-positive serology and absence of endolabyrinthine viral genome since viruses can be in an inactive state at the time of fluid collection. PCR has proved to be a very useful tool in order to investigate infectious causes of deafness even for more than one virus type at a time and in a limited quantity of sample, such as the small volume of

Simulation of reactive polydisperse sprays strongly coupled to unsteady flows in solid rocket motors: Efficient strategy using Eulerian Multi-Fluid methods

NASA Astrophysics Data System (ADS)

Sibra, A.; Dupays, J.; Murrone, A.; Laurent, F.; Massot, M.

2017-06-01

In this paper, we tackle the issue of the accurate simulation of evaporating and reactive polydisperse sprays strongly coupled to unsteady gaseous flows. In solid propulsion, aluminum particles are included in the propellant to improve the global performances but the distributed combustion of these droplets in the chamber is suspected to be a driving mechanism of hydrodynamic and acoustic instabilities. The faithful prediction of two-phase interactions is a determining step for future solid rocket motor optimization. When looking at saving computational ressources as required for industrial applications, performing reliable simulations of two-phase flow instabilities appears as a challenge for both modeling and scientific computing. The size polydispersity, which conditions the droplet dynamics, is a key parameter that has to be accounted for. For moderately dense sprays, a kinetic approach based on a statistical point of view is particularly appropriate. The spray is described by a number density function and its evolution follows a Williams-Boltzmann transport equation. To solve it, we use Eulerian Multi-Fluid methods, based on a continuous discretization of the size phase space into sections, which offer an accurate treatment of the polydispersion. The objective of this paper is threefold: first to derive a new Two Size Moment Multi-Fluid model that is able to tackle evaporating polydisperse sprays at low cost while accurately describing the main driving mechanisms, second to develop a dedicated evaporation scheme to treat simultaneously mass, moment and energy exchanges with the gas and between the sections. Finally, to design a time splitting operator strategy respecting both reactive two-phase flow physics and cost/accuracy ratio required for industrial computations. Using a research code, we provide 0D validations of the new scheme before assessing the splitting technique's ability on a reference two-phase flow acoustic case. Implemented in the industrial

Fluid evolution during burial and Variscan deformation in the Lower Devonian rocks of the High-Ardenne slate belt (Belgium): sources and causes of high-salinity and C-O-H-N fluids

NASA Astrophysics Data System (ADS)

Kenis, I.; Muchez, Ph.; Verhaert, G.; Boyce, A.; Sintubin, M.

2005-08-01

Fluid inclusions in quartz veins of the High-Ardenne slate belt have preserved remnants of prograde and retrograde metamorphic fluids. These fluids were examined by petrography, microthermometry and Raman analysis to define the chemical and spatial evolution of the fluids that circulated through the metamorphic area of the High-Ardenne slate belt. The earliest fluid type was a mixed aqueous/gaseous fluid (H2O-NaCl-CO2-(CH4-N2)) occurring in growth zones and as isolated fluid inclusions in both the epizonal and anchizonal part of the metamorphic area. In the central part of the metamorphic area (epizone), in addition to this mixed aqueous/gaseous fluid, primary and isolated fluid inclusions are also filled with a purely gaseous fluid (CO2-N2-CH4). During the Variscan orogeny, the chemical composition of gaseous fluids circulating through the Lower Devonian rocks in the epizonal part of the slate belt, evolved from an earlier CO2-CH4-N2 composition to a later composition enriched in N2. Finally, a late, Variscan aqueous fluid system with a H2O-NaCl composition migrated through the Lower Devonian rocks. This latest type of fluid can be observed in and outside the epizonal metamorphic part of the High-Ardenne slate belt. The chemical composition of the fluids throughout the metamorphic area, shows a direct correlation with the metamorphic grade of the host rock. In general, the proportion of non-polar species (i.e. CO2, CH4, N2) with respect to water and the proportion of non-polar species other than CO2 increase with increasing metamorphic grade within the slate belt. In addition to this spatial evolution of the fluids, the temporal evolution of the gaseous fluids is indicative for a gradual maturation due to metamorphism in the central part of the basin. In addition to the maturity of the metamorphic fluids, the salinity of the aqueous fluids also shows a link with the metamorphic grade of the host-rock. For the earliest and latest fluid inclusions in the anchizonal

High Density Thermal Energy Storage with Supercritical Fluids

NASA Technical Reports Server (NTRS)

Ganapathi, Gani B.; Wirz, Richard

2012-01-01

A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

Bioactive ceramic-based materials with designed reactivity for bone tissue regeneration

PubMed Central

Ohtsuki, Chikara; Kamitakahara, Masanobu; Miyazaki, Toshiki

2009-01-01

Bioactive ceramics have been used clinically to repair bone defects owing to their biological affinity to living bone; i.e. the capability of direct bonding to living bone, their so-called bioactivity. However, currently available bioactive ceramics do not satisfy every clinical application. Therefore, the development of novel design of bioactive materials is necessary. Bioactive ceramics show osteoconduction by formation of biologically active bone-like apatite through chemical reaction of the ceramic surface with surrounding body fluid. Hence, the control of their chemical reactivity in body fluid is essential to developing novel bioactive materials as well as biodegradable materials. This paper reviews novel bioactive materials designed based on chemical reactivity in body fluid. PMID:19158015

Association of stem cell factor and high-sensitivity C reactive protein concentrations in crevicular fluid and serum in patients with chronic periodontitis with and without type 2 diabetes.

PubMed

Kalra, Nitish; Pradeep, Avani R; Priyanka, Ningappa; Kumari, Minal

2013-03-01

The aim of the present study was to clarify whether there is any correlation between the levels of high-sensitivity C reactive protein (hs-CRP) and stem cell factor (SCF) in serum and gingival crevicular fluid (GCF) of patients with chronic periodontitis (CP) with and without type 2 diabetes mellitus (DM). A total of 40 subjects were divided into 3 groups: 10 periodontally healthy subjects (Group 1), 15 CP patients (Group 2), and 15 type 2 DM patients with CP (Group 3). Levels of hs-CRP and SCF in GCF and serum were quantified using different techniques. The clinical outcomes evaluated were gingival index (GI), probing depth (PD) and clinical attachment level (CAL), and the correlations of the two inflammatory mediators with clinical parameters were evaluated. The levels of these inflammatory mediators increased continuously from group 1 to group 2, and to group 3. The serum levels of both hs-CRP and SCF were correlated with PD in patients with CP (P < 0.05). SCF levels were correlated with PD in Group 3 (P < 0.05). The fact that the levels of hs-CRP and SCF were highest in DM patients with CP suggests that the presence of a systemic condition has a profound effect on the levels of inflammatory mediators, both locally at sites of periodontal disease, and elsewhere.

Is Cerebrospinal Fluid C-reactive Protein a Better Tool than Blood C-reactive Protein in Laboratory Diagnosis of Meningitis in Children?

PubMed Central

Malla, Kalpana K.; Malla, Tejesh; Rao, K. Seshagiri; Basnet, Sahisnuta; Shah, Ravi

2013-01-01

Objectives: This study aimed to test whether C-reactive protein (CRP) measurement could differentiate between different types of meningitis and become a routine test. Methods: A prospective study included 140 children admitted to Manipal Teaching Hospital, Pokhara, Nepal, between July 2009 and June 2011. The subjects had a blood test and detailed cerebrospinal fluid (CSF) analysis, including blood and CSF CRP levels. Results: Of those admitted, 31.1% had pyogenic meningitis (PM), 26.2% partially treated meningitis (PPM), 33% viral meningitis (VM), and 9.7% tubercular meningitis (TBM), with 26.4% controls. Organisms were isolated in 12.5% of the cases by blood culture and 25% of cases through CSF culture. Blood CRP was positive in all groups, with the highest values in PM (53.12 ± 28.88 mg/dl) and PPM (47.55 ± 34.34 mg/dl); this was not statistically significant (P = 0.08). The CSF CRP levels were significantly higher (P <0.001) in PM (45.75 ± 28.50 mg/dl) and PPM (23.11 ± 23.98 mg/dl). The sensitivity and specificity of blood CRP was 90.62%, 88.88%, 64.7%, 70% and 32.4%, 30.97%, 24.52%, 26.12% and that of CSF CRP was 96.87%, 66.66%, 20.58%, 10% and 74.73%, 63.71%, 50.94%, 55.35% for PM, PPM, VM and TBM, respectively. Conclusion: Because of its high sensitivity, both CSF CRP and blood CRP can be used to screen for bacterial meningitis (both PM and PPM). CSF CRP screening yielded results with a higher specificity than blood CRP; hence, it can be a supportive test along with CSF cytology, biochemistry, and microbiology for diagnosing meningitis. PMID:23573388

Numerical solution of chemically reactive non-Newtonian fluid flow: Dual stratification

NASA Astrophysics Data System (ADS)

Rehman, Khalil Ur; Malik, M. Y.; Khan, Abid Ali; Zehra, Iffat; Zahri, Mostafa; Tahir, M.

2017-12-01

We have found that only a few attempts are available in the literature relatively to the tangent hyperbolic fluid flow induced by stretching cylindrical surfaces. In particular, temperature and concentration stratification effects have not been investigated until now with respect to the tangent hyperbolic fluid model. Therefore, we have considered the tangent hyperbolic fluid flow induced by an acutely inclined cylindrical surface in the presence of both temperature and concentration stratification effects. To be more specific, the fluid flow is attained with the no slip condition, which implies that the bulk motion of the fluid particles is the same as the stretching velocity of a cylindrical surface. Additionally, the flow field situation is manifested with heat generation, mixed convection and chemical reaction effects. The flow partial differential equations give a complete description of the present problem. Therefore, to trace out the solution, a set of suitable transformations is introduced to convert these equations into ordinary differential equations. In addition, a self-coded computational algorithm is executed to inspect the numerical solution of these reduced equations. The effect logs of the involved parameters are provided graphically. Furthermore, the variations of the physical quantities are examined and given with the aid of tables. It is observed that the fluid temperature is a decreasing function of the thermal stratification parameter and a similar trend is noticed for the concentration via the solutal stratification parameter.

Geochemical modeling of fluid-fluid and fluid-mineral interactions during geological CO2 storage

NASA Astrophysics Data System (ADS)

Zhu, C.; Ji, X.; Lu, P.

2013-12-01

The long time required for effective CO2 storage makes geochemical modeling an indispensable tool for CCUS. One area of geochemical modeling research that is in urgent need is impurities in CO2 streams. Permitting impurities, such as H2S, in CO2 streams can lead to potential capital and energy savings. However, predicting the consequences of co-injection of CO2 and impurities into geological formations requires the understanding of the phase equilibrium and fluid-fluid interactions. To meet this need, we developed a statistical associating fluid theory (SAFT)-based equation of state (EOS) for the H2S-CO2-H2O-NaCl system at 373.15 high pressures. Furthermore, the EoS can be incorporated into reservoir simulators so that the dynamic development of mixed fluid plumes in the reservoir can be simulated. Accurate modeling of fluid-mineral interactions must confront unresolved uncertainties of silicate dissolution - precipitation reaction kinetics. Most prominent among these uncertainties is the well-known lab-field apparent discrepancy in dissolution rates. Although reactive transport models that simulate the interactions between reservoir rocks and brine, and their attendant effects on porosity and permeability changes, have proliferated, whether these results have acceptable uncertainties are unknown. We have conducted a series of batch experiments at elevated temperatures and numerical simulations of coupled dissolution and precipitation reactions. The results show that taking into account

Fluid-mediated redox transfer in subduction zones: Measuring the intrinsic fO2 of slab fluids in the lab

NASA Astrophysics Data System (ADS)

Iacovino, K.; Till, C. B.

2017-12-01

It is widely observed that arc magmas are the most oxidized magmas on Earth. One frequently cited explanation calls on the flux of aqueous fluid from the highly oxidized down-going slab to catalyze sub-arc mantle melting and impose a highly oxidized redox signature on the mantle wedge. Fluid inclusions from sub-arc mantle xenoliths provide evidence that "slab fluids" may be highly oxidizing (fO2 QFM+1.5; Brandon & Draper, 1996; Frost and Ballhaus, 1998), but for decades, determination of the precise reactive mechanism potentially responsible for the transfer of O2 from slab to mantle has been elusive. Pure H2O has been shown to have insufficient oxidizing capacity to affect mantle redox, but H2O-rich fluids may facilitate the mobilization of Fe3+ or other multivalent cations and/or O2 transfer via the reduction of sulfate, particularly if such fluids are hypersaline. Here we present the first results from experiments designed to investigate fluid-mediated element transfer, including redox reactions, at the slab-mantle interface. These data include the first direct measurements of the intrinsic oxygen fugacity of fluids released during slab dehydration using sliding binary alloy redox sensors. Experiments were performed on natural Fe3+-bearing antigorite serpentinite at 1-2 GPa and 800°C in a piston cylinder at Arizona State University, analogous to conditions in a subducting slab and sufficient to cause the breakdown of starting material into forsteritic olivine, Mg-rich clinopyroxene, magnetite, and aqueous fluid. Experimental time series allow for the detection of (and correction for) any buffering effect on the sample by the experimental assembly. Initial results indicate that the dehydration of sulfur-free antigorite serpentinite can generate fluids with fO2 several orders of magnitude above that of MORB mantle and similar to those observed in natural sub-arc fluid inclusions. Careful measurements of the chemistry of fluid and solid run products will elucidate

Kinetic Determinants of Reactive Strength in Highly Trained Sprint Athletes.

PubMed

Douglas, Jamie; Pearson, Simon; Ross, Angus; McGuigan, Mike

2018-06-01

Douglas, J, Pearson, S, Ross, A, and McGuigan, M. Kinetic determinants of reactive strength in highly trained sprint athletes. J Strength Cond Res 32(6): 1562-1570, 2018-The purpose of this study was to determine the braking and propulsive phase kinetic variables underpinning reactive strength in highly trained sprint athletes in comparison with a nonsprint-trained control group. Twelve highly trained sprint athletes and 12 nonsprint-trained participants performed drop jumps (DJs) from 0.25, 0.50, and 0.75 m onto a force plate. One familiarization session was followed by an experimental testing session within the same week. Reactive strength index (RSI), contact time, flight time, and leg stiffness were determined. Kinetic variables including force, power, and impulse were assessed within the braking and propulsive phases. Sprint-trained athletes demonstrated higher RSI vs. nonsprint-trained participants across all drop heights {3.02 vs. 2.02; ES (±90% confidence limit [CL]): 3.11 ± 0.86}. This difference was primarily attained by briefer contact times (0.16 vs. 0.22 seconds; effect size [ES]: -1.49 ± 0.53) with smaller differences observed for flight time (0.50 vs. 0.46 seconds; ES: 0.53 ± 0.58). Leg stiffness, braking and propulsive phase force, and power were higher in sprint-trained athletes. Very large differences were observed in mean braking force (51 vs. 38 N·kg; ES: 2.57 ± 0.73) which was closely associated with contact time (r ±90% CL: -0.93 ± 0.05). Sprint-trained athletes exhibited superior reactive strength than nonsprint-trained participants. This was due to the ability to strike the ground with a stiffer leg spring, an enhanced expression of braking force, and possibly an increased utilization of elastic structures. The DJ kinetic analysis provides additional insight into the determinants of reactive strength which may inform subsequent testing and training.

Cardiovascular Reactivity in Patients With Major Depressive Disorder With High- or Low-Level Depressive Symptoms: A Cross-Sectional Comparison of Cardiovascular Reactivity to Laboratory-Induced Mental Stress.

PubMed

Wang, Mei-Yeh; Chiu, Chen-Huan; Lee, Hsin-Chien; Su, Chien-Tien; Tsai, Pei-Shan

2016-03-01

Depression increases the risk of adverse cardiac events. Cardiovascular reactivity is defined as the pattern of cardiovascular responses to mental stress. An altered pattern of cardiovascular reactivity is an indicator of subsequent cardiovascular disease. Because depression and adverse cardiac events may have a dose-dependent association, this study examined the differences in cardiovascular reactivity to mental stress between patients with major depressive disorder (MDD) with high depression levels and those with low depression levels. Moreover, autonomic nervous system regulation is a highly plausible biological mechanism for the pattern of cardiovascular reactivity to mental stress. The association between cardiovascular reactivity and parameters of heart rate variability (HRV), an index for quantifying autonomic nervous system activity modulation, was thus examined. This study included 88 patients with MDD. HRV was measured before stress induction. The Stroop Color and Word Test and mirror star-tracing task were used to induce mental stress. We observed no significant association between depressive symptom level and any of the cardiovascular reactivity parameters. Cardiovascular reactivity to mental stress was comparable between patients with MDD with high-level depressive symptoms and those with low-level depressive symptoms. After adjusting for confounding variables, the high-frequency domain of HRV was found to be an independent predictor of the magnitude of heart rate reactivity (β = -.33, p = .002). In conclusion, the magnitude of cardiovascular reactivity may be independent of depression severity in patients with MDD. The autonomic regulation of cardiovascular responses to mental stress primarily influences heart rate reactivity in patients with MDD. © The Author(s) 2015.

Synthesis of high-temperature viscosity stabilizer used in drilling fluid

NASA Astrophysics Data System (ADS)

Zhang, Yanna; Luo, Huaidong; Shi, Libao; Huang, Hongjun

2018-02-01

Abstract For a well performance drilling fluid, when it operates in deep wells under high temperature, the most important property required is the thermal stability. The drilling fluid properties under high temperature can be controlled by proper selection of viscosity stabilizer, which can capture oxygen to protect polymer agent in the drilling fluid. In this paper a viscosity stabilizer PB-854 is described, which was synthesized by 4-phenoxybutyl bromide, paraformaldehyde, and phloroglucinol using etherification method and condensation reaction. We studied the effect of catalyst dosage, temperature, time, and stirring rate on the synthetic yield. Under this condition: molar ratio of 2-tert-Butylphenol, paraformaldehyde and phloroglucinol of 2:1:2.5, reacting temperature of 100 °C, stirring rate of 100 r min-1, and mass content of catalyst of 15 %, char yield of 5-bromine-3-tert-butyl salicylaldehyde reached 86 %. Under this condition: molar ratio of 5-bromine-3-tert-butyl salicylaldehyde and phloroglucinol of 4, reacting temperature of 60 °C, reacting time of 30 min, volume content of sulphuric acid of 80 %, char yield of the target product viscosity stabilizer PB-854 is 86%. Finally, in this paper, infrared spectroscopy is adopted to analyse the structure of the synthetic product PB-854.The improvement in the stability of drilling fluid was further shown after adding the viscosity stabilizer in the common polymer drilling fluid under high temperature conditions of 120 °C ˜ 180 °C. The results show significant change in terms of fluid stability in the presence of this new stabilizer as it provides better stability.

Measurement and reduction of micro-bubble formation in high-viscosity fluids

NASA Astrophysics Data System (ADS)

Tom, Glenn; Liu, Wei

2012-03-01

Gases at high drive pressure can initially dissolve into the fluids used in lithography and other critical processes during the fabrication of integrated circuits. In the low pressure portion of the dispense train, the dissolved gases can revert to bubbles. These bubbles can: 1. Affect the compressibility of the working fluid and change the flow characteristics of the dispense heads which require frequent re-tuning of the coating tools. 2. Contribute to defect formation if the bubbles are trapped on the surface of the wafer. Photosensitive Polyimides (PI) have high viscosities (1000 to 20,000 cP). Because of the high viscosity, high-powered, expensive pumps are needed to effectively remove the fluid from its container. Suction from the pump filling cycle easily causes cavitation, which can create flow rate variability, and micro-bubble formation. It is a common practice to apply pressure to the PI resists to minimize cavitation in the pump. The trade-off to this practice is the entrainment (dissolution) of the drive gas into the resist and the risk of micro-bubbles forming later in the dispense train. In the current study, ATMI measured the effects of two methods of pressure dispense from the container on the amount of gas entrained in a viscous fluid: (1) indirect pressure dispense and (2) direct pressure dispense. The main analytical method employed to measure the amount of dissolved gases is a gas chromatograph (GC), which can measure the concentration of gases dissolved in a volatile fluid. It is not suitable to measure gases in low volatility fluids. The new test method developed, however, is capable of measuring dissolved gases in low volatility fluids.

Perioperative fluid management: comparison of high, medium and low fluid volume on tissue oxygen pressure in the small bowel and colon.

PubMed

Hiltebrand, L B; Pestel, G; Hager, H; Ratnaraj, J; Sigurdsson, G H; Kurz, A

2007-11-01

Insufficient blood flow and oxygenation in the intestinal tract is associated with increased incidence of postoperative complications after bowel surgery. High fluid volume administration may prevent occult regional hypoperfusion and intestinal tissue hypoxia. We tested the hypothesis that high intraoperative fluid volume administration increases intestinal wall tissue oxygen pressure during laparotomy. In all, 27 pigs were anaesthetized, ventilated and randomly assigned to one of the three treatment groups (n = 9 in each) receiving low (3 mL kg-1 h-1), medium (7 mL kg-1 h-1) or high (20 mL kg-1 h-1) fluid volume treatment with lactated Ringer's solution. All animals received 30% and 100% inspired oxygen in random order. Cardiac index was measured with thermodilution and tissue oxygen pressure with a micro-oximetry system in the jejunum and colon wall and subcutaneous tissue. Groups receiving low and medium fluid volume treatment had similar systemic haemodynamics. The high fluid volume group had significantly higher mean arterial pressure, cardiac index and subcutaneous tissue oxygenation. Tissue oxygen pressures in the jejunum and colon were comparable in all three groups. The three different fluid volume regimens tested did not affect tissue oxygen pressure in the jejunum and colon, suggesting efficient autoregulation of intestinal blood flow in healthy subjects undergoing uncomplicated abdominal surgery.

Microscale imaging and identification of Fe speciation and distribution during fluid-mineral reactions under highly reducing conditions.

PubMed

Mayhew, L E; Webb, S M; Templeton, A S

2011-05-15

The oxidation state, speciation, and distribution of Fe are critical determinants of Fe reactivity in natural and engineered environments. However, it is challenging to follow dynamic changes in Fe speciation in environmental systems during progressive fluid-mineral interactions. Two common geological and aquifer materials-basalt and Fe(III) oxides-were incubated with saline fluids at 55 °C under highly reducing conditions maintained by the presence of Fe(0). We tracked changes in Fe speciation after 48 h (incipient water-rock reaction) and 10 months (extensive water-rock interaction) using synchrotron-radiation μXRF maps collected at multiple energies (ME) within the Fe K-edge. Immediate PCA analysis of the ME maps was used to optimize μXANES analyses; in turn, refitting the ME maps with end-member XANES spectra enabled us to detect and spatially resolve the entire variety of Fe-phases present in the system. After 48 h, we successfully identified and mapped the major Fe-bearing components of our samples (Fe(III) oxides, basalt, and rare olivine), as well as small quantities of incipient brucite associated with olivine. After 10 months, the Fe(III)-oxides remained stable in the presence of Fe(0), whereas significant alteration of basalt to minnesotaite and chlinochlore had occurred, providing new insights into heterogeneous Fe speciation in complex geological media under highly reducing conditions.

Persistent high job demands and reactivity to mental stress predict future ambulatory blood pressure.

PubMed

Steptoe, A; Cropley, M

2000-05-01

To test the hypothesis that work stress (persistent high job demands over 1 year) in combination with high reactivity to mental stress predict ambulatory blood pressure. Assessment of cardiovascular responses to standardized behavioural tasks, job demands, and ambulatory blood pressure over a working day and evening after 12 months. We studied 81 school teachers (26 men, 55 women), 36 of whom experienced persistent high job demands over 1 year, while 45 reported lower job demands. Participants were divided on the basis of high and low job demands, and high and low systolic pressure reactions to an uncontrollable stress task. Blood pressure and concurrent physical activity were monitored using ambulatory apparatus from 0900 to 2230 h on a working day. Cardiovascular stress reactivity was associated with waist/hip ratio. Systolic and diastolic pressure during the working day were greater in high job demand participants who were stress reactive than in other groups, after adjustment for age, baseline blood pressure, body mass index and negative affectivity. The difference was not accounted for by variations in physical activity. Cardiovascular stress reactivity and sustained psychosocial stress may act in concert to increase cardiovascular risk in susceptible individuals.

Solid-phase classical complement activation by C-reactive protein (CRP) is inhibited by fluid-phase CRP-C1q interaction

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

Sjoewall, Christopher; Wetteroe, Jonas; Bengtsson, Torbjoern

2007-01-05

C-reactive protein (CRP) interacts with phosphorylcholine (PC), Fc{gamma} receptors, complement factor C1q and cell nuclear constituents, yet its biological roles are insufficiently understood. The aim was to characterize CRP-induced complement activation by ellipsometry. PC conjugated with keyhole limpet hemocyanin (PC-KLH) was immobilized to cross-linked fibrinogen. A low-CRP serum with different amounts of added CRP was exposed to the PC-surfaces. The total serum protein deposition was quantified and deposition of IgG, C1q, C3c, C4, factor H, and CRP detected with polyclonal antibodies. The binding of serum CRP to PC-KLH dose-dependently triggered activation of the classical pathway. Unexpectedly, the activation was efficientlymore » down-regulated at CRP levels >150 mg/L. Using radial immunodiffusion, CRP-C1q interaction was observed in serum samples with high CRP concentrations. We propose that the underlying mechanism depends on fluid-phase interaction between C1q and CRP. This might constitute another level of complement regulation, which has implications for systemic lupus erythematosus where CRP is often low despite flare-ups.« less

21 CFR 866.5270 - C-reactive protein immuno-logical test system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... the C-reactive protein in serum and other body fluids. Measurement of C-reactive protein aids in evaluation of the amount of injury to body tissues. (b) Classification. Class II (performance standards). ....5270 Section 866.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

21 CFR 866.5270 - C-reactive protein immuno-logical test system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... the C-reactive protein in serum and other body fluids. Measurement of C-reactive protein aids in evaluation of the amount of injury to body tissues. (b) Classification. Class II (performance standards). ....5270 Section 866.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

21 CFR 866.5270 - C-reactive protein immuno-logical test system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... the C-reactive protein in serum and other body fluids. Measurement of C-reactive protein aids in evaluation of the amount of injury to body tissues. (b) Classification. Class II (performance standards). ....5270 Section 866.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

21 CFR 866.5270 - C-reactive protein immuno-logical test system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... the C-reactive protein in serum and other body fluids. Measurement of C-reactive protein aids in evaluation of the amount of injury to body tissues. (b) Classification. Class II (performance standards). ....5270 Section 866.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

Attenuation of Chemical Reactivity of Shale Matrixes following Scale Precipitation

NASA Astrophysics Data System (ADS)

Li, Q.; Jew, A. D.; Kohli, A. H.; Alalli, G.; Kiss, A. M.; Kovscek, A. R.; Zoback, M. D.; Brown, G. E.; Maher, K.; Bargar, J.

2017-12-01

Introduction of fracture fluids into shales initiates a myriad of fluid-rock reactions that can strongly influence migration of fluid and hydrocarbon through shale/fracture interfaces. Due to the extremely low permeability of shale matrixes, studies on chemical reactivity of shales have mostly focused on shale surfaces. Shale-fluid interactions inside within shale matrixes have not been examined, yet the matrix is the primary conduit through which hydrocarbons and potential contaminants are transmitted. To characterize changes in matrix mineralogy, porosity, diffusivity, and permeability during hydraulic stimulation, we reacted Marcellus (high clay and low carbonate) and Eagle Ford (low clay and high carbonate) shale cores with fracture fluids for 3 weeks at elevated pressure and temperature (80 oC, and 77 bars). In the carbonate-poor Marcellus system, fluid pH increased from 2 to 4, and secondary Fe(OH)3 precipitates were observed in the fluid. Sulfur X-ray fluorescence maps show that fluids had saturated and reacted with the entire 1-cm-diameter core. In the carbonate-rich Eagle Ford system, pH increased from 2 to 6 due to calcite dissolution. When additional Ba2+ and SO42- were present (log10(Q/K)=1.3), extensive barite precipitation was observed in the matrix of the Eagle Ford core (and on the surface). Barite precipitation was also observed on the surface of the Marcellus core, although to a lesser extent. In the Marcellus system, the presence of barite scale attenuated diffusivity in the matrix, as demonstrated by sharply reduced Fe leaching and much less sulfide oxidation. Systematic studies in homogeneous solution show that barite scale precipitation rates are highly sensitive to pH, salinity, and the presence of organic compounds. These findings imply that chemical reactions are not confined to shale/fluid interfaces but can penetrate into shale matrices, and that barite scale formation can clog diffusion pathways for both fluid and hydrocarbon.

Natural occurrence and significance of fluids indicating high pressure and temperature

USGS Publications Warehouse

Roedder, E.

1981-01-01

Most natural minerals have formed from a fluid phase such as a silicate melt or a saline aqueous solution. Fluid inclusions are tiny volumes of such fluids that were trapped within the growing crystals. These inclusions can provide valuable but sometimes ambiguous data on the temperature, pressure, and composition of these fluids, many of which are not available from any other source. They also provide "visual autoclaves" in which it is possible to watch, through the microscope, the actual phase changes take place as the inclusions are heated. This paper reviews the methods of study and the results obtained, mainly on inclusions formed from highly concentrated solutions, at temperatures ???500??C. Many such fluids have formed as a result of immiscibility with silicate melt in igneous or high-temperature metamorphic rocks. These include fluids consisting of CO2, H2O, or hydrosaline melts that were <50% H2O. From the fluid inclusion evidence it is clear that a boiling, very hot, very saline fluid was present during the formation of most of the porphyry copper deposits in the world. Similarly, from the inclusion evidence it is clear that early (common) pegmatites formed from essentially silicate melts and that the late, rare-element-bearing and chamber-type pegmatites formed from a hydrosaline melt or a more dilute water solution. The evidence on whether this change in composition from early to late solutions was generally continuous or involved immiscibility is not as clear. ?? 1981.

Correlation of human S100A12 (EN-RAGE) and high-sensitivity C-reactive protein as gingival crevicular fluid and serum markers of inflammation in chronic periodontitis and type 2 diabetes.

PubMed

Pradeep, A R; Martande, Santosh S; Singh, Sonender Pal; Suke, Deepak Kumar; Raju, Arjun P; Naik, Savitha B

2014-04-01

The aim of the present study was to evaluate the levels and correlation of human S100A12 and high-sensitivity C-reactive protein (hs-CRP) in gingival crevicular fluid (GCF) and serum in chronic periodontitis (CP) subjects with and without type 2 diabetes mellitus (DM). A total of 44 subjects were divided into three groups: group 1 had 10 periodontally healthy subjects, group 2 consisted of 17 CP subjects and group 3 had 17 type 2 DM subjects with CP. GCF and serum levels of human S100A12 and hs-CRP were quantified using enzyme-linked immunosorbent assay and immunoturbidimetric analysis, respectively. The clinical outcomes evaluated were gingival index, probing depth and clinical attachment level and the correlations of the two inflammatory mediators with clinical parameters were evaluated. Both human S100A12 and hs-CRP levels increased from group 1 to group 2 to group 3. The GCF and serum values of both these inflammatory mediators correlated positively with each other and with the periodontal parameters evaluated (p < 0.05). Human S100A12 and hs-CRP can be considered as possible GCF and serum markers of inflammatory activity in CP and DM.

Mixing high-viscosity fluids via acoustically driven bubbles

NASA Astrophysics Data System (ADS)

Orbay, Sinem; Ozcelik, Adem; Lata, James; Kaynak, Murat; Wu, Mengxi; Huang, Tony Jun

2017-01-01

We present an acoustofluidic micromixer which can perform rapid and homogeneous mixing of highly viscous fluids in the presence of an acoustic field. In this device, two high-viscosity polyethylene glycol (PEG) solutions were co-injected into a three-inlet PDMS microchannel with the center inlet containing a constant stream of nitrogen flow which forms bubbles in the device. When these bubbles were excited by an acoustic field generated via a piezoelectric transducer, the two solutions mixed homogenously due to the combination of acoustic streaming, droplet ejection, and bubble eruption effects. The mixing efficiency of this acoustofluidic device was evaluated using PEG-700 solutions which are ~106 times more viscous than deionized (DI) water. Our results indicate homogenous mixing of the PEG-700 solutions with a ~0.93 mixing index. The acoustofluidic micromixer is compact, inexpensive, easy to operate, and has the capacity to mix highly viscous fluids within 50 ms.

An Environmental Impact Assessment of Perfluorocarbon Thermal Working Fluid Use On Board Crewed Spacecraft

NASA Technical Reports Server (NTRS)

Perry, Jay L.; Arnold, William a.

2006-01-01

The design and operation of crewed spacecraft requires identifying and evaluating chemical compounds that may present reactivity and compatibility risks with the environmental control and life support (ECLS) system. Such risks must be understood so that appropriate design and operational controls, including specifying containment levels, can be instituted or an appropriate substitute material selected. Operational experience acquired during the International Space Station (ISS) program has found that understanding ECLS system and environmental impact presented by thermal control system working fluids is imperative to safely operating any crewed space exploration vehicle. Perfluorocarbon fluids are used as working fluids in thermal control fluid loops on board the ISS. Also, payload hardware developers have identified perfluorocarbon fluids as preferred thermal control working fluids. Interest in using perfluorocarbon fluids as thermal control system working fluids for future crewed space vehicles and outposts is high. Potential hazards associated with perfluorocarbon fluids are discussed with specific attention given to engineering assessment of ECLS system compatibility, compatibility testing results, and spacecraft environmental impact. Considerations for perfluorocarbon fluid use on crewed spacecraft and outposts are summarized.

Final Report: Molecular Mechanisms of Interfacial Reactivity in Near Surface and Extreme Geochemical Environments (DE-SC0009362)

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

Dixon, David A

2016-03-27

The prediction of the long-term stability and safety of geologic sequestration of greenhouse gases requires a detailed understanding of subsurface transport and chemical interactions between the disposed greenhouse gases and the geologic media. In this regard, mineral-fluid interactions are of prime importance since reactions that occur on or near the interface can assist in the long term sequestration of CO2 by trapping in mineral phases such as carbonates, as well as influencing the subsurface migration of the disposed fluids via creation or plugging of pores or fractures in the host rock strata. Previous research on mineral-fluid interaction for subsurface CO2more » storage has focused almost entirely on the aqueous phase, i.e., reactivity with aqueous solutions or brines containing dissolved CO2. However, interactions with neat to water-saturated non-aqueous fluids are of equal if not greater importance since supercritical CO2 (scCO2) is less dense than the aqueous phase or oil which will create a buoyant scCO2 plume that ultimately will dominate the pore volume within the caprock, and the injected scCO2 will contain water soon after injection and this water can be highly reactive. Collectively, therefore, mineral interactions with water-saturated scCO2-dominated fluids are pivotal and could result in the stable sequestration of CO2 by trapping in mineral phases such as metal carbonates within otherwise permeable zones in the caprock. The primary objective is to unravel the molecular mechanisms governing the reactivity of mineral phases important in the geologic sequestration of CO2 with variably wet supercritical carbon dioxide as a function of T, P, and mineral structure using computational chemistry. This work is in close collaboration with the PNNL Geosciences effort. The focus of the work at The University of Alabama is computational studies of the formation of magnesium and calcium carbonates and oxides and their reactivity and providing computational

Nitrogen-rich heterocycles as reactivity retardants in shocked insensitive explosives.

PubMed

Manaa, M Riad; Reed, Evan J; Fried, Laurence E; Goldman, Nir

2009-04-22

We report the first quantum-based multiscale simulations to study the reactivity of shocked perfect crystals of the insensitive energetic material triaminotrinitrobenzene (TATB). Tracking chemical transformations of TATB experiencing overdriven shock speeds of 9 km/s for up to 0.43 ns and 10 km/s for up to 0.2 ns reveal high concentrations of nitrogen-rich heterocyclic clusters. Further reactivity of TATB toward the final decomposition products of fluid N(2) and solid carbon is inhibited due to the formation of these heterocycles. Our results thus suggest a new mechanism for carbon-rich explosive materials that precedes the slow diffusion-limited process of forming the bulk solid from carbon clusters and provide fundamental insight at the atomistic level into the long reaction zone of shocked TATB.

Simulations of Congenital Septal Defect Closure and Reactivity Testing in Patient-Specific Models of the Pediatric Pulmonary Vasculature: A 3D Numerical Study With Fluid-Structure Interaction

PubMed Central

Hunter, Kendall S.; Lanning, Craig J.; Chen, Shiuh-Yung J.; Zhang, Yanhang; Garg, Ruchira; Ivy, D. Dunbar; Shandas, Robin

2014-01-01

Clinical imaging methods are highly effective in the diagnosis of vascular pathologies, but they do not currently provide enough detail to shed light on the cause or progression of such diseases, and would be hard pressed to foresee the outcome of surgical interventions. Greater detail of and prediction capabilities for vascular hemodynamics and arterial mechanics are obtained here through the coupling of clinical imaging methods with computational techniques. Three-dimensional, patient-specific geometric reconstructions of the pediatric proximal pulmonary vasculature were obtained from x-ray angiogram images and meshed for use with commercial computational software. Two such models from hypertensive patients, one with multiple septal defects, the other who underwent vascular reactivity testing, were each completed with two sets of suitable fluid and structural initial and boundary conditions and used to obtain detailed transient simulations of artery wall motion and hemodynamics in both clinically measured and predicted configurations. The simulation of septal defect closure, in which input flow and proximal vascular stiffness were decreased, exhibited substantial decreases in proximal velocity, wall shear stress (WSS), and pressure in the post-op state. The simulation of vascular reactivity, in which distal vascular resistance and proximal vascular stiffness were decreased, displayed negligible changes in velocity and WSS but a significant drop in proximal pressure in the reactive state. This new patient-specific technique provides much greater detail regarding the function of the pulmonary circuit than can be obtained with current medical imaging methods alone, and holds promise for enabling surgical planning. PMID:16813447

Cerebrospinal fluid and plasma C-reactive protein and aggression in personality-disordered subjects: a pilot study.

PubMed

Coccaro, Emil F; Lee, Royce; Coussons-Read, Mary

2015-02-01

C-reactive protein (CRP), in the plasma, serves as a marker of systemic inflammation and has been shown to correlate with history of actual aggressive behavior, and as a personality trait of aggressive tendency, in human subjects. This pilot study was conducted to determine if plasma CRP levels are correlated with cerebrospinal fluid levels (CSF CRP) and if CSF CRP also correlates with aggression. If so, this would suggest a role for central inflammatory processes in human aggression. Both plasma and basal lumbar CSF samples were obtained from 17 subjects with DSM-5 personality disorder and assayed for CRP. Plasma and CSF CRP levels were correlated (r = 0.65, p = 0.005) and each correlated with aggression (Plasma: r = 0.53, p = 0.029; CSF: r = 0.84, p < 0.001). When considered simultaneously, CSF CRP, but not plasma CRP, uniquely correlated with aggression. No relationship was seen with other measures of psychopathology. These data suggest a positive relationship between central nervous system CRP and aggression in humans.

Thermal properties and surface reactivity in simulated body fluid of new strontium ion-containing phosphate glasses.

PubMed

Massera, J; Petit, L; Cardinal, T; Videau, J J; Hupa, M; Hupa, L

2013-06-01

In this paper, we investigate the effect of SrO substitution for CaO in 50P₂O₅-10Na₂-(40-x)CaO-xSrO glass system (x from 0 to 40) on the thermal and structural properties and also on the glass reactivity in simulated body fluid (SBF) in order to find new glass candidates for biomedical glass fibers. The addition of SrO at the expense of CaO seems to restrain the leaching of phosphate ions in the solution limiting the reduction of the solution pH. We observed the formation of an apatite layer at the surface of the glasses when in contact with SBF. SrO and MgO were found in the apatite layer of the strontium ion-containing glasses, the concentration of which increases with an increase of SrO content. We think that it is the presence of MgO and SrO in the layer which limits the leaching of phosphate in the solution and thus the glass dissolution in SBF.

Deployable Emergency Shutoff Device Blocks High-Velocity Fluid Flows

NASA Technical Reports Server (NTRS)

Nabors, Sammy A.

2015-01-01

NASA's Marshall Space Flight Center has developed a device and method for blocking the flow of fluid from an open pipe. Motivated by the sea-bed oil-drilling catastrophe in the Gulf of Mexico in 2010, NASA innovators designed the device to plug, control, and meter the flow of gases and liquids. Anchored with friction fittings, spikes, or explosively activated fasteners, the device is well-suited for harsh environments and high fluid velocities and pressures. With the addition of instrumentation, it can also be used as a variable area flow metering valve that can be set based upon flow conditions. With robotic additions, this patent-pending innovation can be configured to crawl into a pipe then anchor and activate itself to block or control fluid flow.

The profile of high school students’ scientific literacy on fluid dynamics

NASA Astrophysics Data System (ADS)

Parno; Yuliati, L.; Munfaridah, N.

2018-05-01

This study aims to describe the profile of scientific literacy of high school students on Fluid Dynamics materials. Scientific literacy is one of the ability to solve daily problems in accordance with the context of materials related to science and technology. The study was conducted on 90 high school students in Sumbawa using survey design. Data were collected using an instrument of scientific literacy for high school students on dynamic fluid materials. Data analysis was conducted descriptively to determine the students’ profile of scientific literacy. The results showed that high school students’ scientific literacy on Fluid Dynamics materials was in the low category. The highest average is obtained on indicators of scientific literacy i.e. the ability to interpret data and scientific evidence. The ability of scientific literacy is related to the mastery of concepts and learning experienced by students, therefore it is necessary to use learning that can trace this ability such as Science, Technology, Engineering, and Mathematics (STEM).

High frequency flow-structural interaction in dense subsonic fluids

NASA Technical Reports Server (NTRS)

Liu, Baw-Lin; Ofarrell, J. M.

1995-01-01

Prediction of the detailed dynamic behavior in rocket propellant feed systems and engines and other such high-energy fluid systems requires precise analysis to assure structural performance. Designs sometimes require placement of bluff bodies in a flow passage. Additionally, there are flexibilities in ducts, liners, and piping systems. A design handbook and interactive data base have been developed for assessing flow/structural interactions to be used as a tool in design and development, to evaluate applicable geometries before problems develop, or to eliminate or minimize problems with existing hardware. This is a compilation of analytical/empirical data and techniques to evaluate detailed dynamic characteristics of both the fluid and structures. These techniques have direct applicability to rocket engine internal flow passages, hot gas drive systems, and vehicle propellant feed systems. Organization of the handbook is by basic geometries for estimating Strouhal numbers, added mass effects, mode shapes for various end constraints, critical onset flow conditions, and possible structural response amplitudes. Emphasis is on dense fluids and high structural loading potential for fatigue at low subsonic flow speeds where high-frequency excitations are possible. Avoidance and corrective measure illustrations are presented together with analytical curve fits for predictions compiled from a comprehensive data base.

A qualitative view of cryogenic fluid injection into high speed flows

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Schlumberger, J.; Proctor, M.

1991-01-01

The injection of supercritical pressure, subcritical temperature fluids, into a 2-D, ambient, static temperature and static pressure supersonic tunnel and free jet supersonic nitrogen flow field was observed. Observed patterns with fluid air were the same as those observed for fluid nitrogen injected into the tunnel at 90 deg to the supersonic flow. The nominal injection pressure was of 6.9 MPa and tunnel Mach number was 2.7. When injected directly into and opposing the tunnel exhaust flow, the observed patterns with fluid air were similar to those observed for fluid nitrogen but appeared more diffusive. Cryogenic injection creates a high density region within the bow shock wake but the standoff distance remains unchanged from the gaseous value. However, as the temperature reaches a critical value, the shock faded and advanced into the supersonic stream. For both fluids, nitrogen and air, the phenomena was completely reversible.

Witness of fluid-flow organization during high-pressure antigorite dehydration

NASA Astrophysics Data System (ADS)

López Sánchez-Vizcaíno, Vicente; Padrón-Navarta, José Alberto; Garrido, Carlos J.; Gómez-Pugnaire, María. Teresa

2010-05-01

The link between devolatilization reactions and fluid flow is crucial to unravel important geodynamic processes in subduction zones as deformation and element transfer is extremely controlled by the presence of water. At high confining pressure, significant fluid pressure gradients are expected in a reacting rock being dehydrated, because of its rather limited permeability [1]. Compactation-driven fluid flow seems to be an intrinsic mechanism occurring at devolatilization of viscolastic rocks. Nevertheless, and despite the important implications of this coupled deformation/fluid-migration mechanism for fluid transport, a conclusive confirmation of these processes by petrological and textural evidences in metamorphic terrains has been hampered by the scarcity of devolatilization fronts in the geological record. Evidences of high-pressure antigorite dehydration found at Cerro del Almirez (Betic Cordillera, Spain) [2] represent a noteworthy exception. Here, the transition between the hydrous protolith (antigorite serpentinite) and the prograde product assemblage (olivine + orthopyroxene + chlorite, chlorite harzburgite) is extremely well preserved and can be surveyed in detail. The maximum stability of the antigorite has been experimentally determined at ~680°C at 1.6-1.9 GPa [3]. Antigorite dehydration is accompanied by release of high amounts of high-pressure water-rich fluids (~ 9 wt.% fluid). Distinctive layers (up to 1 m thick) of transitional lithologies occur in between atg-serpentinite and chl-harburgite all along the devolatilization front, consisting of (1) chlorite-antigorite olivine-serpentinite, which gradually changes to (2) chlorite-antigorite-olivine-orthopyroxene serpentinite. These transitional lithologies are more massive and darker in color than atg-serpentinite and largely consist of coarse sized grains of antigorite and chlorite (250-500 μm). Antigorite in these assemblages is characterized by microstructural disorder features, which are

Chemical reactivity parameters (HSAB) applied to magma evolution and ore formation

NASA Astrophysics Data System (ADS)

Vigneresse, Jean-Louis

2012-11-01

mechanisms that control sequestration and transport of metals within the different phases during igneous activity. Based on high gas/melt partitioning for metals and similar reactivity, the gaseous phase is more attractive for metals than silicate melts. The presence of halogens in the fluid phase tends to reinforce hardness, making the fluid phase attractive for hard metals such as Sn or W. Conversely, the presence of S decreases hardness of the fluid phase that becomes attractive for soft metals such as Au, Ag and Cu.

Latent Virus Reactivation: From Space to Earth

NASA Technical Reports Server (NTRS)

Mehta, Satish K.; Cohrs, Randall J.; Gilden, Donald H.; Tyring, Stephen K.; Castro, Victoria A.; Ott, C. Mark; Pierson, Duane L.

2010-01-01

Reactivation of latent viruses is a recognized consequence of decreased immunity. More recently viral reactivation has been identified as an important in vivo indicator of clinically relevant immune changes. Viral reactivation can be determined quickly and easily by the presence of virus in saliva and other body fluids. Real-time polymerase chain reaction (PCR) is a highly sensitive and specific molecular method to detect the presence of specific viral DNA. Studies in astronauts demonstrated that herpes simplex virus type 1(HSV-1), Epstein-Barr Virus (EBV), cytomegalovirus (CMV), and varicella zoster virus (VZV) reactivate at rates above normal during and after spaceflight in response to moderately decreased T-cell immunity. This technology was expanded to patients on Earth beginning with human immune deficiency virus (HIV) immuno-compromised patients. The HIV patients shed EBV in saliva at rates 9-fold higher than observed in astronauts demonstrating that the level of EBV shedding reflects the severity of impaired immunity. Whereas EBV reactivation is not expected to produce serious effects in astronauts on missions of 6 months or less, VZV reactivation in astronauts could produce shingles. Reactivation of live, infectious VZV in astronauts with no symptoms was demonstrated in astronauts during and after spaceflight. We applied our technology to study VZV-induced shingles in patients. In a study of 54 shingles patients, we showed salivary VZV was present in every patient on the day antiviral (acyclovir) treatment was initiated. Pain and skin lesions decreased with antiviral treatment. Corresponding decreases in levels of VZV were also observed and accompanied recovery. Although the level of VZV in shingles patients before the treatment was generally higher than those found in astronauts, lower range of VZV numbers in shingles patients overlapped with astronaut s levels. This suggests a potential risk of shingles to astronauts resulting from reactivation of VZV. In

Environmentally Friendly, Rheoreversible, Hydraulic-fracturing Fluids for Enhanced Geothermal Systems

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

Shao, Hongbo; Kabilan, Senthil; Stephens, Sean A.

Cost-effective creation of high-permeability reservoirs inside deep crystalline bedrock is the primary challenge for the feasibility of enhanced geothermal systems (EGS). Current reservoir stimulation entails adverse environmental impacts and substantial economic costs due to the utilization of large volumes of water “doped” with chemicals including rheology modifiers, scale and corrosion inhibitors, biocides, friction reducers among others where, typically, little or no information of composition and toxicity is disclosed. An environmentally benign, CO2-activated, rheoreversible fracturing fluid has recently been developed that significantly enhances rock permeability at effective stress significantly lower than current technology. We evaluate the potential of this novel fracturingmore » fluid for application on geothermal sites under different chemical and geomechanical conditions, by performing laboratory-scale fracturing experiments with different rock sources under different confining pressures, temperatures, and pH environments. The results demonstrate that CO2-reactive aqueous solutions of environmentally amenable Polyallylamine (PAA) represent a highly versatile fracturing fluid technology. This fracturing fluid creates/propagates fracture networks through highly impermeable crystalline rock at significantly lower effective stress as compared to control experiments where no PAA was present, and permeability enhancement was significantly increased for PAA compared to conventional hydraulic fracturing controls. This was evident in all experiments, including variable rock source/type, operation pressure and temperature (over the entire range for EGS applications), as well as over a wide range of formation-water pH values. This versatile novel fracturing fluid technology represents a great alternative to industrially available fracturing fluids for cost-effective and competitive geothermal energy production.« less

A Gas-Kinetic Scheme for Reactive Flows

NASA Technical Reports Server (NTRS)

Lian,Youg-Sheng; Xu, Kun

1998-01-01

In this paper, the gas-kinetic BGK scheme for the compressible flow equations is extended to chemical reactive flow. The mass fraction of the unburnt gas is implemented into the gas kinetic equation by assigning a new internal degree of freedom to the particle distribution function. The new variable can be also used to describe fluid trajectory for the nonreactive flows. Due to the gas-kinetic BGK model, the current scheme basically solves the Navier-Stokes chemical reactive flow equations. Numerical tests validate the accuracy and robustness of the current kinetic method.

Reactive power planning under high penetration of wind energy using Benders decomposition

DOE PAGES

Xu, Yan; Wei, Yanli; Fang, Xin; ...

2015-11-05

This study addresses the optimal allocation of reactive power volt-ampere reactive (VAR) sources under the paradigm of high penetration of wind energy. Reactive power planning (RPP) in this particular condition involves a high level of uncertainty because of wind power characteristic. To properly model wind generation uncertainty, a multi-scenario framework optimal power flow that considers the voltage stability constraint under the worst wind scenario and transmission N 1 contingency is developed. The objective of RPP in this study is to minimise the total cost including the VAR investment cost and the expected generation cost. Therefore RPP under this condition ismore » modelled as a two-stage stochastic programming problem to optimise the VAR location and size in one stage, then to minimise the fuel cost in the other stage, and eventually, to find the global optimal RPP results iteratively. Benders decomposition is used to solve this model with an upper level problem (master problem) for VAR allocation optimisation and a lower problem (sub-problem) for generation cost minimisation. Impact of the potential reactive power support from doubly-fed induction generator (DFIG) is also analysed. Lastly, case studies on the IEEE 14-bus and 118-bus systems are provided to verify the proposed method.« less

Molybdenum cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures

NASA Astrophysics Data System (ADS)

Matsuda, Kazuhiro; Tamura, Kozaburo; Katoh, Masahiro; Inui, Masanori

2004-03-01

We have developed a sample cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures. All parts of the cell are made of molybdenum which is resistant to the chemical corrosion of alkali metals. Single crystalline molybdenum disks electrolytically thinned down to 40 μm were used as the walls of the cell through which x rays pass. The crystal orientation of the disks was controlled in order to reduce the background from the cell. All parts of the cell were assembled and brazed together using a high-temperature Ru-Mo alloy. Energy dispersive x-ray diffraction measurements have been successfully carried out for fluid rubidium up to 1973 K and 16.2 MPa. The obtained S(Q) demonstrates the applicability of the molybdenum cell to x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures.

Graphene nanoplatelets as high-performance filtration control material in water-based drilling fluids

NASA Astrophysics Data System (ADS)

Ridha, Syahrir; Ibrahim, Arif; Shahari, Radzi; Fonna, Syarizal

2018-05-01

The main objective of this work is to evaluate the effectiveness of graphene nanoplatelets (GNP) as filtration control materials in water based drilling fluids. Three (3) general samples of water based drilling fluids were prepared including basic potassium chloride (KCl) drilling fluids, nanosilica (NS) drilling fluids and GNP drilling fluids. Several concentrations of NS and GNP were dispersed in controlled formulations of water based drilling fluids. Standard API filtration tests were carried out for comparison purposes as well as High Temperature High Pressure (HTHP) filtration tests at 150 °F (∼66 °C), 250 °F (∼121 °C) and 350 °F (∼177 °C) at a fixed 500 (∼3.45MPa) psi to study the filtration trend as a function of temperature. Mud cake samples from several tests were selectively chosen and analyzed under Field Emission Scanning Electron Microscope (FESEM) for its morphology. Results from this work show that nanoparticle concentrations play a factor in filtration ability of colloid materials in water based drilling fluids when studied at elevated temperature. Low temperature filtration, however, shows only small differences in volume in all the drilling fluid samples. 0.1 ppb concentrations of GNP reduced the fluid loss of 350 °F by 4.6 mL as compared to the similar concentration of NS drilling fluids.

A New Mechanism for Upper Crustal Fluid Flow Driven by Solitary Porosity Waves in Rigid Reactive Media?

NASA Astrophysics Data System (ADS)

Chakraborty, Sumit

2017-10-01

The equations governing the interaction of viscous deformation with porous flow of fluids give rise to wave-like solutions. Such solutions have been explored in the context of melt and fluid flow in the mantle and crust at high temperatures, where ductile behavior occurs. Now it has been shown that the coupling of the kinetics of chemical reactions with fluid flow may give rise to similar solutions. This opens intriguing new possibilities. Porosity waves may arise in low-temperature regimes, and may become more accessible to observation, or they may remain mathematical curiosities because other modes of transport dominate in such settings. A number of possibilities, questions, and future courses of research have been opened up by Omlin et al. (2017).

Spectral Induced Polarization approaches to characterize reactive transport parameters and processes

NASA Astrophysics Data System (ADS)

Schmutz, M.; Franceschi, M.; Revil, A.; Peruzzo, L.; Maury, T.; Vaudelet, P.; Ghorbani, A.; Hubbard, S. S.

2017-12-01

For almost a decade, geophysical methods have explored the potential for characterization of reactive transport parameters and processes relevant to hydrogeology, contaminant remediation, and oil and gas applications. Spectral Induced Polarization (SIP) methods show particular promise in this endeavour, given the sensitivity of the SIP signature to geological material electrical double layer properties and the critical role of the electrical double layer on reactive transport processes, such as adsorption. In this presentation, we discuss results from several recent studies that have been performed to quantify the value of SIP parameters for characterizing reactive transport parameters. The advances have been realized through performing experimental studies and interpreting their responses using theoretical and numerical approaches. We describe a series of controlled experimental studies that have been performed to quantify the SIP responses to variations in grain size and specific surface area, pore fluid geochemistry, and other factors. We also model chemical reactions at the interface fluid/matrix linked to part of our experimental data set. For some examples, both geochemical modelling and measurements are integrated into a SIP physico-chemical based model. Our studies indicate both the potential of and the opportunity for using SIP to estimate reactive transport parameters. In case of well sorted granulometry of the samples, we find that the grain size characterization (as well as the permeabililty for some specific examples) value can be estimated using SIP. We show that SIP is sensitive to physico-chemical conditions at the fluid/mineral interface, including the different pore fluid dissolved ions (Na+, Cu2+, Zn2+, Pb2+) due to their different adsorption behavior. We also showed the relevance of our approach to characterize the fluid/matrix interaction for various organic contents (wetting and non-wetting oils). We also discuss early efforts to jointly

Calculating Mass Diffusion in High-Pressure Binary Fluids

NASA Technical Reports Server (NTRS)

Bellan, Josette; Harstad, Kenneth

2004-01-01

A comprehensive mathematical model of mass diffusion has been developed for binary fluids at high pressures, including critical and supercritical pressures. Heretofore, diverse expressions, valid for limited parameter ranges, have been used to correlate high-pressure binary mass-diffusion-coefficient data. This model will likely be especially useful in the computational simulation and analysis of combustion phenomena in diesel engines, gas turbines, and liquid rocket engines, wherein mass diffusion at high pressure plays a major role.

Fault reactivation by fluid injection considering permeability evolution in fault-bordering damage zones

NASA Astrophysics Data System (ADS)

Yang, Z.; Yehya, A.; Rice, J. R.; Yin, J.

2017-12-01

Earthquakes can be induced by human activity involving fluid injection, e.g., as wastewater disposal from hydrocarbon production. The occurrence of such events is thought to be, mainly, due to the increase in pore pressure, which reduces the effective normal stress and hence the strength of a nearby fault. Change in subsurface stress around suitably oriented faults at near-critical stress states may also contribute. We focus on improving the modeling and prediction of the hydro-mechanical response due to fluid injection, considering the full poroelastic effects and not solely changes in pore pressure in a rigid host. Thus we address the changes in porosity and permeability of the medium due to the changes in the local volumetric strains. Our results also focus on including effects of the fault architecture (low permeability fault core and higher permeability bordering damage zones) on the pressure diffusion and the fault poroelastic response. Field studies of faults have provided a generally common description for the size of their bordering damage zones and how they evolve along their direction of propagation. Empirical laws, from a large number of such observations, describe their fracture density, width, permeability, etc. We use those laws and related data to construct our study cases. We show that the existence of high permeability damage zones facilitates pore-pressure diffusion and, in some cases, results in a sharp increase in pore-pressure at levels much deeper than the injection wells, because these regions act as conduits for fluid pressure changes. This eventually results in higher seismicity rates. By better understanding the mechanisms of nucleation of injection-induced seismicity, and better predicting the hydro-mechanical response of faults, we can assess methodologies and injection strategies to avoid risks of high magnitude seismic events. Microseismic events occurring after the start of injection are very important indications of when injection

High-resolution single-molecule fluorescence imaging of zeolite aggregates within real-life fluid catalytic cracking particles.

PubMed

Ristanović, Zoran; Kerssens, Marleen M; Kubarev, Alexey V; Hendriks, Frank C; Dedecker, Peter; Hofkens, Johan; Roeffaers, Maarten B J; Weckhuysen, Bert M

2015-02-02

Fluid catalytic cracking (FCC) is a major process in oil refineries to produce gasoline and base chemicals from crude oil fractions. The spatial distribution and acidity of zeolite aggregates embedded within the 50-150 μm-sized FCC spheres heavily influence their catalytic performance. Single-molecule fluorescence-based imaging methods, namely nanometer accuracy by stochastic chemical reactions (NASCA) and super-resolution optical fluctuation imaging (SOFI) were used to study the catalytic activity of sub-micrometer zeolite ZSM-5 domains within real-life FCC catalyst particles. The formation of fluorescent product molecules taking place at Brønsted acid sites was monitored with single turnover sensitivity and high spatiotemporal resolution, providing detailed insight in dispersion and catalytic activity of zeolite ZSM-5 aggregates. The results point towards substantial differences in turnover frequencies between the zeolite aggregates, revealing significant intraparticle heterogeneities in Brønsted reactivity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Permeability evolution due to dissolution of natural shale fractures reactivated by fracking

NASA Astrophysics Data System (ADS)

Kwiatkowski, Kamil; Kwiatkowski, Tomasz; Szymczak, Piotr

2015-04-01

Investigation of cores drilled from gas-bearing shale formations reveals a relatively large number of calcite-cemented fractures. During fracking, some of these fractures will be reactivated [1-2] and may become important flow paths in the resulting fracture system. In this communication, we investigate numerically the effect of low-pH reactive fluid on such fractures. The low-pH fluids can either be pumped during the initial fracking stage (as suggested e.g. by Grieser et al., [3]) or injected later, as part of enhanced gas recovery (EGR) processes. In particular, it has been suggested that CO2 injection can be considered as a method of EGR [4], which is attractive as it can potentially be combined with simultaneous CO2 sequestration. However, when mixed with brine, CO2 becomes acidic and thus can be a dissolving agent for the carbonate cement in the fractures. The dissolution of the cement leads to the enhancement of permeability and interconnectivity of the fracture network and, as a result, increases the overall capacity of the reservoir. Importantly, we show that the dissolution of such fractures proceeds in a highly non-homogeneous manner - a positive feedback between fluid transport and mineral dissolution leads to the spontaneous formation of pronounced flow channels, frequently referred to as "wormholes". The wormholes carry the chemically active fluid deeper inside the system, which dramatically speeds up the overall permeability increase. If the low-pH fluids are used during fracking, then the non-uniform dissolution becomes important for retaining the fracture permeability, even in the absence of the proppant. Whereas a uniformly etched fracture will close tightly under the overburden once the fluid pressure is removed, the nonuniform etching will tend to maintain the permeability since the less dissolved regions will act as supports to keep more dissolved regions open. [1] Gale, J. F., Reed, R. M., Holder, J. (2007). Natural fractures in the Barnett

Reactivation of a Propped Hydraulic Fracture

NASA Astrophysics Data System (ADS)

Sarvaramini, E.; Garagash, D.

2014-12-01

The problem of massive fluid injection into a pre-existing fracture has many applications in petroleum industry including underground liquid waste disposal and waterflooding to increase recovery from a hydrocarbon reservoir. Understanding the conditions leading to the re-activation of pre-existing fractures and ensuing propagation is critical for a successful injection project design, and it may also help to mitigate potential environmental hazards, such as contamination of underground aquifers and induced seismicity. The problem of injection of a low viscosity fluid into a permeable formation can be distinguished from conventional hydraulic fracture by the mechanism of fluid leak-off. In conventional fracturing, high viscosity and cake building properties of injected fluid limit leak-off to a 1-D boundary layer incasing the crack. In the case of injection of low viscosity fluid into a fracture, leak-off and related pore fluid diffusion will take place over wider range of scales, from 1-D to 2 or 3-D. We consider a pre-existing stationary propped hydraulic fracture with constrained height into which a fluid is injected under constant flow rate. Although the net effective stress on the crack is initially compressive, the proppant keeps the crack open. It is worthwhile to note that during injection and related pressurization of a propped crack, the fracture breakdown is to be achieved prior to the fracture re-opening. Therefore, the effect of the change of the propped fracture storage on the pressurization dynamics can be neglected. The objective of this work is to study the transient pressurization and the onset of the propagation for a propped fracture. To the end, we formulate and solve a general problem of injection into a fracture accounting for viscous dissipation (i.e. non-uniform pressure distribution). We quantify how the fracture breakdown condition depends upon the rock and fluid properties, the in-situ stress and the fluid injection rate. We also

Tick-Tock Goes the Croc: A High-Density EEG Study of Risk-Reactivity and Binge-Drinking.

PubMed

Kiat, John E; Cheadle, Jacob E

2018-05-31

Links between individual differences in risk processing and high-risk behaviors such as binge drinking have long been the focus of active research. However, investigations in this area almost exclusively utilize decision-making focused paradigms. This emphasis makes it difficult to assess links between risk behaviors and raw risk reactivity independent of decision and feedback processes. A deeper understanding of this association has the potential to shed light on the role of risk reactivity in high-risk behavior susceptibility. To contribute towards this aim, this study utilizes a popular risk-taking game, the crocodile dentist, to assess links between individual differences in decision-free risk-reactivity and reported binge drinking frequency levels. In this task, participants engage in a series of decision-free escalating risk responses. Risk-reactivity was assessed by measuring Late Positive Potential responses towards risk-taking action initiation cues using high-density 256-Channel EEG. The results indicate that, after controlling for overall alcohol consumption frequency, higher rates of reported binge drinking are associated with both increased general risk-taking responsivity and increased risk-reactivity escalation as a function of risk level. These findings highlight intriguing links between risk reactivity and binge drinking frequency, making key contributions in the areas of risk-taking and affective science.

Thermodynamical effects and high resolution methods for compressible fluid flows

NASA Astrophysics Data System (ADS)

Li, Jiequan; Wang, Yue

2017-08-01

One of the fundamental differences of compressible fluid flows from incompressible fluid flows is the involvement of thermodynamics. This difference should be manifested in the design of numerical schemes. Unfortunately, the role of entropy, expressing irreversibility, is often neglected even though the entropy inequality, as a conceptual derivative, is verified for some first order schemes. In this paper, we refine the GRP solver to illustrate how the thermodynamical variation is integrated into the design of high resolution methods for compressible fluid flows and demonstrate numerically the importance of thermodynamic effects in the resolution of strong waves. As a by-product, we show that the GRP solver works for generic equations of state, and is independent of technical arguments.

Method for generating a highly reactive plasma for exhaust gas aftertreatment and enhanced catalyst reactivity

DOEpatents

Whealton, John H.; Hanson, Gregory R.; Storey, John M.; Raridon, Richard J.; Armfield, Jeffrey S.; Bigelow, Timothy S.; Graves, Ronald L.

2002-01-01

A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime, high frequency, high power bursts of low-duty factor microwaves sufficient to generate a plasma discharge and passing a gas to be treated through the discharge so as to cause dissociative reduction of the exhaust gases and enhanced catalyst reactivity through application of the pulsed microwave fields directly to the catalyst material sufficient to cause a polarizability catastrophe and enhanced heating of the metal crystallite particles of the catalyst, and in the presence or absence of the plasma. The invention also includes a reactor for aftertreatment of exhaust gases.

Isotope systematics of Icelandic thermal fluids

NASA Astrophysics Data System (ADS)

Stefánsson, Andri; Hilton, David R.; Sveinbjörnsdóttir, Árný E.; Torssander, Peter; Heinemeier, Jan; Barnes, Jaime D.; Ono, Shuhei; Halldórsson, Sæmundur Ari; Fiebig, Jens; Arnórsson, Stefán

2017-05-01

Thermal fluids in Iceland range in temperature from < 10 °C to > 440 °C and are dominated by water (> 97 mol%) with a chloride concentration from < 10 ppm to > 20,000 ppm. The isotope systematics of the fluids reveal many important features of the source(s) and transport properties of volatiles at this divergent plate boundary. Studies spanning over four decades have revealed a large range of values for δD (- 131 to + 3.3‰), tritium (- 0.4 to + 13.8 TU), δ18O (- 20.8 to + 2.3‰), 3He/4He (3.1 to 30.4 RA), δ11B (- 6.7 to + 25.0‰), δ13C∑ CO2 (- 27.4 to + 4.6‰), 14C∑ CO2 (+ 0.6 to + 118 pMC), δ13CCH4 (- 52.3 to - 17.8‰), δ15N (- 10.5 to + 3.0‰), δ34S∑ S- II (- 10.9 to + 3.4‰), δ34SSO4 (- 2.0 to + 21.2‰) and δ37Cl (- 1.0 to + 2.1‰) in both liquid and vapor phases. Based on this isotopic dataset, the thermal waters originate from meteoric inputs and/or seawater. For other volatiles, degassing of mantle-derived melts contributes to He, CO2 and possibly also to Cl in the fluids. Water-basalt interaction also contributes to CO2 and is the major source of H2S, SO4, Cl and B in the fluids. Redox reactions additionally influence the composition of the fluids, for example, oxidation of H2S to SO4 and reduction of CO2 to CH4. Air-water interaction mainly controls N2, Ar and Ne concentrations. The large range of many non-reactive volatile isotope ratios, such as δ37Cl and 3He/4He, indicate heterogeneity of the mantle and mantle-derived melts beneath Iceland. In contrast, the large range of many reactive isotopes, such as δ13C∑ CO2 and δ34S∑ S- II, are heavily affected by processes occurring within the geothermal systems, including fluid-rock interaction, depressurization boiling, and isotopic fractionation between secondary minerals and the aqueous and vapor species. Variations due to these geothermal processes may exceed differences observed among various crust and mantle sources, highlighting the importance and effects of chemical

Peer Relations and Peer Deviance as Predictors of Reactive and Proactive Aggression among High School Girls

ERIC Educational Resources Information Center

Uz Bas, Asli; Öz Soysal, Fatma Selda

2016-01-01

This study aimed to investigate associations between reactive and proactive aggression and peer relations and peer deviance among high school girls. A total of 442 high school students participated in this study. Reactive-Proactive Aggression Questionnaire, the Peer Relations Scale, and the Peer Deviance Scale were used to collect data. Results…

Extracellular Fluid/Intracellular Fluid Volume Ratio as a Novel Risk Indicator for All-Cause Mortality and Cardiovascular Disease in Hemodialysis Patients

PubMed Central

Kim, Eun-Jung; Choi, Myung-Jin; Lee, Jeoung-Hwan; Oh, Ji-Eun; Seo, Jang-Won; Lee, Young-Ki; Yoon, Jong-Woo; Kim, Hyung-Jik; Noh, Jung-Woo

2017-01-01

Background In hemodialysis patients, fluid overload and malnutrition are accompanied by extracellular fluid (ECF) expansion and intracellular fluid (ICF) depletion, respectively. We investigated the relationship between ECF/ICF ratio (as an integrated marker reflecting both fluid overload and malnutrition) and survival and cardiovascular disease (CVD) in the context of malnutrition-inflammation-arteriosclerosis (MIA) complex. Methods Seventy-seven patients from a single hemodialysis unit were prospectively enrolled. The ECF/ICF volume was measured by segmental multi-frequency bioimpedance analysis. MIA and volume status were measured by serum albumin, C-reactive protein (CRP), pulse wave velocity (PWV) and plasma B-type natriuretic peptide (BNP), respectively. Results The mean ECF/ICF ratio was 0.56±0.06 and the cut-off value for maximum discrimination of survival was 0.57. Compared with the low ECF/ICF group, the high ECF/ICF group (ratio≥0.57, 42%) had higher all-cause mortality, CVD, CRP, PWV, and BNP, but lower serum albumin. During the 5-year follow-up, 24 all-cause mortality and 38 CVD occurred (18 and 24, respectively, in the high ECF/ICF group versus 6 and 14 respectively in the low ECF/ICF group, P<0.001). In the adjusted Cox analysis, the ECF/ICF ratio nullifies the effects of the MIA and volume status on survival and CVD and was an independent predictor of all-cause mortality and CVD: hazard ratio (95% confidence interval); 1.12 (1.01–1.25) and 1.09 (1.01–1.18) for a 0.01 increase in the ECF/ICF ratio. The degree of malnutrition (albumin), inflammation (CRP), arteriosclerosis (PWV), and fluid overload (BNP) were correlated well with the ECF/ICF ratio. Conclusions Hemodialysis patients with high ECF/ICF ratio are not only fluid overloaded, but malnourished and have stiff artery with more inflammation. The ECF/ICF ratio is highly related to the MIA complex, and is a major risk indicator for all-cause mortality and CVD. PMID:28099511

A reactive transport model for Marcellus shale weathering

NASA Astrophysics Data System (ADS)

Heidari, Peyman; Li, Li; Jin, Lixin; Williams, Jennifer Z.; Brantley, Susan L.

2017-11-01

Shale formations account for 25% of the land surface globally and contribute a large proportion of the natural gas used in the United States. One of the most productive shale-gas formations is the Marcellus, a black shale that is rich in organic matter and pyrite. As a first step toward understanding how Marcellus shale interacts with water in the surface or deep subsurface, we developed a reactive transport model to simulate shale weathering under ambient temperature and pressure conditions, constrained by soil and water chemistry data. The simulation was carried out for 10,000 years since deglaciation, assuming bedrock weathering and soil genesis began after the last glacial maximum. Results indicate weathering was initiated by pyrite dissolution for the first 1000 years, leading to low pH and enhanced dissolution of chlorite and precipitation of iron hydroxides. After pyrite depletion, chlorite dissolved slowly, primarily facilitated by the presence of CO2 and organic acids, forming vermiculite as a secondary mineral. A sensitivity analysis indicated that the most important controls on weathering include the presence of reactive gases (CO2 and O2), specific surface area, and flow velocity of infiltrating meteoric water. The soil chemistry and mineralogy data could not be reproduced without including the reactive gases. For example, pyrite remained in the soil even after 10,000 years if O2 was not continuously present in the soil column; likewise, chlorite remained abundant and porosity remained small if CO2 was not present in the soil gas. The field observations were only simulated successfully when the modeled specific surface areas of the reactive minerals were 1-3 orders of magnitude smaller than surface area values measured for powdered minerals. Small surface areas could be consistent with the lack of accessibility of some fluids to mineral surfaces due to surface coatings. In addition, some mineral surface is likely interacting only with equilibrated pore

High-performance holographic technologies for fluid-dynamics experiments

PubMed Central

Orlov, Sergei S.; Abarzhi, Snezhana I.; Oh, Se Baek; Barbastathis, George; Sreenivasan, Katepalli R.

2010-01-01

Modern technologies offer new opportunities for experimentalists in a variety of research areas of fluid dynamics. Improvements are now possible in the state-of-the-art in precision, dynamic range, reproducibility, motion-control accuracy, data-acquisition rate and information capacity. These improvements are required for understanding complex turbulent flows under realistic conditions, and for allowing unambiguous comparisons to be made with new theoretical approaches and large-scale numerical simulations. One of the new technologies is high-performance digital holography. State-of-the-art motion control, electronics and optical imaging allow for the realization of turbulent flows with very high Reynolds number (more than 107) on a relatively small laboratory scale, and quantification of their properties with high space–time resolutions and bandwidth. In-line digital holographic technology can provide complete three-dimensional mapping of the flow velocity and density fields at high data rates (over 1000 frames per second) over a relatively large spatial area with high spatial (1–10 μm) and temporal (better than a few nanoseconds) resolution, and can give accurate quantitative description of the fluid flows, including those of multi-phase and unsteady conditions. This technology can be applied in a variety of problems to study fundamental properties of flow–particle interactions, rotating flows, non-canonical boundary layers and Rayleigh–Taylor mixing. Some of these examples are discussed briefly. PMID:20211881

REACTIVE HAZARDOUS AIR POLLUTANTS (HAPS) IN THE RESPIRATORY TRACT; EFFECTS IN HEALTHY AND SUSCEPTIBLE INDIVIDUALS

EPA Science Inventory

Exposure-dose-effect linkages for chemically reactive air toxic compounds. The respiratory epithelium is coated with an "airway lining fluid" that serves as a defense against chlorine and other reactive gases because it contains proteins, lipids and antioxidants that can absorb...

High-sensitivity C-reactive protein predicts mortality but not stroke

PubMed Central

Elkind, M S.V.; Luna, J M.; Moon, Y P.; Liu, K M.; Spitalnik, S L.; Paik, M C.; Sacco, R L.

2009-01-01

Objective: To determine whether high-sensitivity C-reactive protein (hsCRP) and serum amyloid A (SAA) predict stroke, vascular events, and mortality in a prospective cohort study. Background: Markers of inflammation have been associated with risk of myocardial infarction (MI). Their association with stroke is controversial. Methods: The Northern Manhattan Study includes a stroke-free community-based cohort study in participants aged ≥40 years (median follow-up 7.9 years). hsCRP and SAA were measured using nephelometry. Cox proportional hazards models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for the association of markers with risk of ischemic stroke and other outcomes after adjusting for demographics and risk factors. Results: hsCRP measurements were available in 2,240 participants (mean age 68.9 ± 10.1 years; 64.2% women; 18.8% white, 23.5% black, and 55.1% Hispanic). The median hsCRP was 2.5 mg/L. Compared with those with hsCRP <1 mg/L, those with hsCRP >3 mg/L were at increased risk of ischemic stroke in a model adjusted for demographics (HR = 1.60, 95% CI 1.06–2.41), but the effect was attenuated after adjusting for other risk factors (adjusted HR = 1.20, 95% CI 0.78–1.86). hsCRP >3 mg/L was associated with risk of MI (adjusted HR = 1.70, 95% CI 1.04–2.77) and death (adjusted HR = 1.55, 95% CI 1.23–1.96). SAA was not associated with stroke risk. Conclusion: In this multiethnic cohort, high-sensitivity C-reactive protein (hsCRP) was not associated with ischemic stroke, but was modestly associated with myocardial infarction and mortality. The value of hsCRP and serum amyloid A may depend on population characteristics such as age and other risk factors. GLOSSARY AHA = American Heart Association; BP = blood pressure; CDC = Centers for Disease Control and Prevention; CI = confidence interval; CRP = C-reactive protein; CUMC = Columbia University Medical Center; HR = hazard ratio; hsCRP = high-sensitivity C-reactive

A Reactive-Transport Model Describing Methanogen Growth and Methane Production in Diffuse Flow Vents at Axial Seamount

NASA Astrophysics Data System (ADS)

Algar, C. K.

2015-12-01

Hydrogenotrophic methanogenesis is an important mode of metabolism in deep-sea hydrothermal vents. Diffuse vent fluids often show a depletion in hydrogen with a corresponding increase in methane relative to pure-mixing of end member fluid and seawater, and genomic surveys show an enrichment in genetic sequences associated with known methanogens. However, because we cannot directly sample the subseafloor habitat where these organisms are living, constraining the size and activity of these populations remains a challenge and limits our ability to quantify the role they play in vent biogeochemistry. Reactive-transport modeling may provide a useful tool for approaching this problem. Here we present a reactive-transport model describing methane production along the flow-path of hydrothermal fluid from its high temperature end-member to diffuse venting at the seafloor. The model is set up to reflect conditions at several diffuse vents in the Axial Seamount. The model describes the growth of the two dominant thermophilic methanogens, Methanothermococcus and Methanocaldococcus, observed at Axial seamount. Monod and Arrhenius constants for Methanothermococcus thermolithotrophicus and Methanocaldococcus jannaschii were obtained for the model using chemostat and bottle experiments at varying temperatures. The model is used to investigate the influence of different mixing regimes on the subseafloor populations of these methanogens. By varying the model flow path length and subseafloor cell concentrations, and fitting to observed hydrogen and methane concentrations in the venting fluid, the subseafloor biomass, fluid residence time, and methane production rate can be constrained.

Highly oxidising fluids generated during serpentinite breakdown in subduction zones.

PubMed

Debret, B; Sverjensky, D A

2017-09-04

Subduction zones facilitate chemical exchanges between Earth's deep interior and volcanism that affects habitability of the surface environment. Lavas erupted at subduction zones are oxidized and release volatile species. These features may reflect a modification of the oxidation state of the sub-arc mantle by hydrous, oxidizing sulfate and/or carbonate-bearing fluids derived from subducting slabs. But the reason that the fluids are oxidizing has been unclear. Here we use theoretical chemical mass transfer calculations to predict the redox state of fluids generated during serpentinite dehydration. Specifically, the breakdown of antigorite to olivine, enstatite, and chlorite generates fluids with high oxygen fugacities, close to the hematite-magnetite buffer, that can contain significant amounts of sulfate. The migration of these fluids from the slab to the mantle wedge could therefore provide the oxidized source for the genesis of primary arc magmas that release gases to the atmosphere during volcanism. Our results also show that the evolution of oxygen fugacity in serpentinite during subduction is sensitive to the amount of sulfides and potentially metal alloys in bulk rock, possibly producing redox heterogeneities in subducting slabs.

High-Sensitivity C-Reactive Protein as a Predictor of Cardiovascular Events after ST-Elevation Myocardial Infarction

PubMed Central

Ribeiro, Daniel Rios Pinto; Ramos, Adriane Monserrat; Vieira, Pedro Lima; Menti, Eduardo; Bordin, Odemir Luiz; de Souza, Priscilla Azambuja Lopes; de Quadros, Alexandre Schaan; Portal, Vera Lúcia

2014-01-01

Background The association between high-sensitivity C-reactive protein and recurrent major adverse cardiovascular events (MACE) in patients with ST-elevation myocardial infarction who undergo primary percutaneous coronary intervention remains controversial. Objective To investigate the potential association between high-sensitivity C-reactive protein and an increased risk of MACE such as death, heart failure, reinfarction, and new revascularization in patients with ST-elevation myocardial infarction treated with primary percutaneous coronary intervention. Methods This prospective cohort study included 300 individuals aged >18 years who were diagnosed with ST-elevation myocardial infarction and underwent primary percutaneous coronary intervention at a tertiary health center. An instrument evaluating clinical variables and the Thrombolysis in Myocardial Infarction (TIMI) and Global Registry of Acute Coronary Events (GRACE) risk scores was used. High-sensitivity C-reactive protein was determined by nephelometry. The patients were followed-up during hospitalization and up to 30 days after infarction for the occurrence of MACE. Student's t, Mann-Whitney, chi-square, and logistic regression tests were used for statistical analyses. P values of ≤0.05 were considered statistically significant. Results The mean age was 59.76 years, and 69.3% of patients were male. No statistically significant association was observed between high-sensitivity C-reactive protein and recurrent MACE (p = 0.11). However, high-sensitivity C-reactive protein was independently associated with 30-day mortality when adjusted for TIMI [odds ratio (OR), 1.27; 95% confidence interval (CI), 1.07-1.51; p = 0.005] and GRACE (OR, 1.26; 95% CI, 1.06-1.49; p = 0.007) risk scores. Conclusion Although high-sensitivity C-reactive protein was not predictive of combined major cardiovascular events within 30 days after ST-elevation myocardial infarction in patients who underwent primary angioplasty and stent

Reactive oxygen species from secondary organic aerosols decomposition in water and surrogate lung lining fluid

NASA Astrophysics Data System (ADS)

Tong, H.; Shen, F.; Lakey, P. S. J.; Arangio, A. M.; Socorro, J.; Brune, W. H.; Lucas, K.; Poeschl, U.; Shiraiwa, M.

2016-12-01

Reactive oxygen species (ROS) play a significant role in climate and adverse health effects of air pollutants (Anglada, J. M. et al., 2015; Pöschl and Shiraiwa, 2015). Secondary organic aerosols (SOA) account for a major fraction of fine particles (Jimenez et al., 2009; Huang et al., 2014). Thus, studies on ROS production ability of SOA are important for comprehensive evaluation of the impacts of air particulate matter on climate change and public health. In this study, we have investigated ROS formation by laboratory-generated SOA particles using a variety of different experimental techniques including electron paramagnetic resonance spectrometry, dithiothreitol and fluorometric hydrogen peroxide assays, and LC-MS/MS spectrometry, we found substantial amounts of ROS species such as •OH, O2•-, RO•, R• and H2O2 were generated by isoprene, β-pinene, and naphthalene SOA upon interaction with water and surrogate lung lining fluid. Antioxidants contained in surrogate lung lining fluid scavenge •OH and O2•-efficiently, but not organic radicals. LC-MS/MS analysis and kinetic modeling suggest that organic hydroperoxides, which account for a major fraction of SOA particles (Docherty et al., 2005; Ehn et al., 2014) play a critical role in ROS formation (Tong et al., 2016). We also found the cellular responses of human alveolar basal epithelial (A549) and macrophage cells (THP-1) to SOA could be explained by the ROS yields, indicating a key role of ROS on the cytotoxicity of SOA. Anglada, J. M. et al., Acc. Chem. Res. 48, 575-583, 2015. Docherty, K. S. eta al. Environ. Sci. Technol. 39, 4049-4059, 2005. Ehn, M. et al., Nature 506, 476-479, 2014. Huang, R.-J. et al., Nature 514, 218-222, 2014. Jimenez, J. L. et al., Science 326, 1525-1529, 2009. Pöschl, U., and Shiraiwa, M. Chem. Rev., 115, 4440-4475, 2015. Tong, H. et al., Atmos. Chem. Phys. 16, 1761-1771, 2016.

High Ki-67 Immunohistochemical Reactivity Correlates With Poor Prognosis in Bladder Carcinoma

PubMed Central

Luo, Yihuan; Zhang, Xin; Mo, Meile; Tan, Zhong; Huang, Lanshan; Zhou, Hong; Wang, Chunqin; Wei, Fanglin; Qiu, Xiaohui; He, Rongquan; Chen, Gang

2016-01-01

Abstract Ki-67 is considered as one of prime biomarkers to reflect cell proliferation and immunohistochemical Ki-67 staining has been widely applied in clinical pathology. To solve the widespread controversy whether Ki-67 reactivity significantly predicts clinical prognosis of bladder carcinoma (BC), we performed a comprehensive meta-analysis by combining results from different literature. A comprehensive search was conducted in the Chinese databases of WanFang, China National Knowledge Infrastructure and Chinese VIP as well as English databases of PubMed, ISI web of science, EMBASE, Science Direct, and Wiley online library. Independent studies linking Ki-67 to cancer-specific survival (CSS), disease-free survival (DFS), overall survival (OS), progression-free survival (PFS), and recurrence-free survival (RFS) were included in our meta-analysis. With the cut-off values literature provided, hazard ratio (HR) values between the survival distributions were extracted and later combined with STATA 12.0. In total, 76 studies (n = 13,053 patients) were eligible for the meta-analysis. It was indicated in either univariate or multivariate analysis for survival that high Ki-67 reactivity significantly predicted poor prognosis. In the univariate analysis, the combined HR for CSS, DFS, OS, PFS, and RFS were 2.588 (95% confidence interval [CI]: 1.623–4.127, P < 0.001), 2.697 (95%CI: 1.874–3.883, P < 0.001), 2.649 (95%CI: 1.632–4.300, P < 0.001), 3.506 (95%CI: 2.231–5.508, P < 0.001), and 1.792 (95%CI: 1.409–2.279, P < 0.001), respectively. The pooled HR of multivariate analysis for CSS, DFS, OS, PFS, and RFS were 1.868 (95%CI: 1.343–2.597, P < 0.001), 2.626 (95%CI: 2.089–3.301, P < 0.001), 1.104 (95%CI: 1.008–1.209, P = 0.032), 1.518 (95%CI: 1.299–1.773, P < 0.001), and 1.294 (95%CI: 1.203–1.392, P < 0.001), respectively. Subgroup analysis of univariate analysis by origin showed that Ki-67 reactivity significantly

High fluid pressure and triggered earthquakes in the enhanced geothermal system in Basel, Switzerland

NASA Astrophysics Data System (ADS)

Terakawa, Toshiko; Miller, Stephen A.; Deichmann, Nicholas

2012-07-01

We analyzed 118 well-constrained focal mechanisms to estimate the pore fluid pressure field of the stimulated region during the fluid injection experiment in Basel, Switzerland. This technique, termed focal mechanism tomography (FMT), uses the orientations of slip planes within the prevailing regional stress field as an indicator of the fluid pressure along the plane at the time of slip. The maximum value and temporal change of excess pore fluid pressures are consistent with the known history of the wellhead pressure applied at the borehole. Elevated pore fluid pressures were concentrated within 500 m of the open hole section, which are consistent with the spatiotemporal evolution of the induced microseismicity. Our results demonstrate that FMT is a robust approach, being validated at the meso-scale of the Basel stimulation experiment. We found average earthquake triggering excess pore fluid pressures of about 10 MPa above hydrostatic. Overpressured fluids induced many small events (M < 3) along faults unfavorably oriented relative to the tectonic stress pattern, while the larger events tended to occur along optimally oriented faults. This suggests that small-scale hydraulic networks, developed from the high pressure stimulation, interact to load (hydraulically isolated) high strength bridges that produce the larger events. The triggering pore fluid pressures are substantially higher than that predicted from a linear pressure diffusion process from the source boundary, and shows that the system is highly permeable along flow paths that allow fast pressure diffusion to the boundaries of the stimulated region.

Benchscale Assessment of the Efficacy of a Reactive Core Mat to Isolate PAH-spiked Aquatic Sediments.

PubMed

Meric, Dogus; Barbuto, Sara; Sheahan, Thomas C; Shine, James P; Alshawabkeh, Akram N

2014-01-01

This paper describes the results of a benchscale testing program to assess the efficacy of a reactive core mat (RCM) for short term isolation and partial remediation of contaminated, subaqueous sediments. The 1.25 cm thick RCM (with a core reactive material such as organoclay with filtering layers on top and bottom) is placed on the sediment, and approximately 7.5 - 10 cm of overlying soil is placed on the RCM for stability and protection. A set of experiments were conducted to measure the sorption characteristics of the mat core (organoclay) and sediment used in the experiments, and to determine the fate of semi-volatile organic contaminants and non-reactive tracers through the sediment and reactive mat. The experimental study was conducted on naphthalene-spiked Neponset River (Milton, MA) sediment. The results show nonlinear sorption behavior for organoclay, with sorption capacity increasing with increasing naphthalene concentration. Neponset River sediment showed a notably high sorption capacity, likely due to the relatively high organic carbon fraction (14%). The fate and transport experiments demonstrated the short term efficiency of the reactive mat to capture the contamination that is associated with the post-capping period during which the highest consolidation-induced advective flux occurs, driving solid particles, pore fluid and soluble contaminants toward the reactive mat. The goal of the mat placement is to provide a physical filtering and chemically reactive layer to isolate contamination from the overlying water column. An important finding is that because of the high sorption capacity of the Neponset River sediment, the physical filtering capability of the mat is as critical as its chemical reactive capacity.

CO2 injection into fractured peridotites: a reactive percolation experiment

NASA Astrophysics Data System (ADS)

Escario, S.; Godard, M.; Gouze, P.; Leprovost, R.; Luquot, L.; Garcia-Rios, M.

2017-12-01

Mantle peridotites have the potential to trap CO2 as carbonates. This process observed in ophiolites and in oceanic environments provides a long term and safe storage for CO2. It occurs as a part of a complex suite of fluid-rock reactions involving silicate dissolution and precipitation of hydrous phases, carbonates and minor phases that may in turn modify the hydrodynamic properties and the reactivity of the reacted rocks. The efficiency and lastingness of the process require the renewal of fluids at the mineral-fluid interface. Fractures are dominant flow paths in exhumed mantle sections. This study aims at better understanding the effect of CO2-enriched saline fluids on hydrodynamic and chemical processes through fractured peridotites. Experiments were performed using the reactive percolation bench ICARE Lab 3 - Géosciences Montpellier. It allows monitoring the permeability changes during experiments. Effluents are recurrently sampled for analysing cation concentration, pH and alkalinity. Reacted rock samples were characterized by high resolution X-ray microtomography (ESRF ID19, Grenoble, France) and SEM. Experiments consisted in injecting CO2-enriched brines (NaCl 0.5 M) at a rate of 6 mL.h-1 into artificially fractured cores (9 mm diameter × 20 mm length) of Oman harzburgites at T=170°C and Ptotal = 25 MPa for up to 2 weeks. Fractures are of few µm apertures with rough walls. Three sets of experiments were performed at increasing value of [CO2] (0, 0.1 and 1 mol/kg). All experiments showed a decrease in permeability followed by steady state regime that can be caused by a decrease in the roughness of fracture walls (dissolution dominated process), thus favouring fracture closing, or by the precipitation of secondary phases. Maximum enrichments in Mg, Fe and Ca of the effluent fluids occur during the first 2 hours of the experiments whereas Si displays a maximum enrichment at t = 20 h, suggesting extensive dissolution. Maximum enrichments are observed with

Collisional quenching dynamics and reactivity of highly vibrationally excited molecules

NASA Astrophysics Data System (ADS)

Liu, Qingnan

Highly excited molecules are of great importance in many areas of chemistry including photochemistry. The dynamics of highly excited molecules are affected by the intermolecular and intramolecular energy flow between many different kinds of motions. This thesis reports investigations of the collisional quenching and reactivity of highly excited molecules aimed at understanding the dynamics of highly excited molecules. There are several important questions that are addressed. How do molecules behave in collisions with a bath gas? How do the energy distributions evolve in time? How is the energy partitioned for both the donor and bath molecules after collisions? How do molecule structure, molecule state density and intermolecular potential play the role during collisional energy transfer? To answer these questions, collisional quenching dynamics and reactivity of highly vibrationally excited azabenzene molecules have been studied using high resolution transient IR absorption spectroscopy. The first study shows that the alkylated pyridine molecules that have been excited with Evib˜38,800 cm-1 impart less rotational and translational energy to CO2 than pyridine does. Comparison between the alkylated donors shows that the strong collisions are reduced for donors with longer alkyl chains by lowering the average energy per mode but longer alkyl chain have increased flexibility and higher state densities that enhance energy loss via strong collisions. In the second study, the role of hydrogen bonding interactions is explored in collision of vibrationally excited pyridines with H2O. Substantial difference in the rotational energy of H 2O is correlated with the structure of the global energy minimum. A torque-inducing mechanism is proposed that involves directed movement of H 2O between sigma and pi-hydrogen bonding interactions with the pyridine donors. In the third study the dynamics of strong and weak collisions for highly vibrationally excited methylated pyridine

High-Order Methods for Incompressible Fluid Flow

NASA Astrophysics Data System (ADS)

Deville, M. O.; Fischer, P. F.; Mund, E. H.

2002-08-01

High-order numerical methods provide an efficient approach to simulating many physical problems. This book considers the range of mathematical, engineering, and computer science topics that form the foundation of high-order numerical methods for the simulation of incompressible fluid flows in complex domains. Introductory chapters present high-order spatial and temporal discretizations for one-dimensional problems. These are extended to multiple space dimensions with a detailed discussion of tensor-product forms, multi-domain methods, and preconditioners for iterative solution techniques. Numerous discretizations of the steady and unsteady Stokes and Navier-Stokes equations are presented, with particular sttention given to enforcement of imcompressibility. Advanced discretizations. implementation issues, and parallel and vector performance are considered in the closing sections. Numerous examples are provided throughout to illustrate the capabilities of high-order methods in actual applications.

High-Performance Java Codes for Computational Fluid Dynamics

NASA Technical Reports Server (NTRS)

Riley, Christopher; Chatterjee, Siddhartha; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

2001-01-01

The computational science community is reluctant to write large-scale computationally -intensive applications in Java due to concerns over Java's poor performance, despite the claimed software engineering advantages of its object-oriented features. Naive Java implementations of numerical algorithms can perform poorly compared to corresponding Fortran or C implementations. To achieve high performance, Java applications must be designed with good performance as a primary goal. This paper presents the object-oriented design and implementation of two real-world applications from the field of Computational Fluid Dynamics (CFD): a finite-volume fluid flow solver (LAURA, from NASA Langley Research Center), and an unstructured mesh adaptation algorithm (2D_TAG, from NASA Ames Research Center). This work builds on our previous experience with the design of high-performance numerical libraries in Java. We examine the performance of the applications using the currently available Java infrastructure and show that the Java version of the flow solver LAURA performs almost within a factor of 2 of the original procedural version. Our Java version of the mesh adaptation algorithm 2D_TAG performs within a factor of 1.5 of its original procedural version on certain platforms. Our results demonstrate that object-oriented software design principles are not necessarily inimical to high performance.

Neuronal damage and shortening of lifespan in C. elegans by peritoneal dialysis fluid: Protection by glyoxalase-1

PubMed Central

Schlotterer, Andrea; Pfisterer, Friederike; Kukudov, Georgi; Heckmann, Britta; Henriquez, Daniel; Morath, Christian; Krämer, Bernhard K.; Hammes, Hans-Peter; Schwenger, Vedat; Morcos, Michael

2018-01-01

Glucose and glucose degradation products (GDPs), contained in peritoneal dialysis (PD) fluids, contribute to the formation of advanced glycation end-products (AGEs). Local damaging effects, resulting in functional impairment of the peritoneal membrane, are well studied. It is also supposed that detoxification of AGE precursors by glyoxalase-1 (GLO1) has beneficial effects on GDP-mediated toxicity. The aim of the current study was to analyze systemic detrimental effects of PD fluids and their prevention by glyoxlase-1. Wild-type and GLO1-overexpressing Caenorhabditis elegans (C. elegans) were cultivated in the presence of low- and high-GDP PD fluids containing 1.5 or 4% glucose. Lifespan, neuronal integrity and neuronal functions were subsequently studied. The higher concentrations of glucose and GDP content resulted in a decrease of maximum lifespan by 2 (P<0.01) and 9 days (P<0.001), respectively. Exposure to low- and high-GDP fluids caused reduction of neuronal integrity by 34 (P<0.05) and 41% (P<0.05). Cultivation of animals in the presence of low-GDP fluid containing 4% glucose caused significant impairment of neuronal function, reducing relative and absolute head motility by 58.5 (P<0.01) and 56.7% (P<0.01), respectively; and relative and absolute tail motility by 55.1 (P<0.05) and 55.0% (P<0.05), respectively. Taken together, GLO1 overexpression protected from glucose-induced lifespan reduction, neurostructural damage and neurofunctional damage under low-GDP-conditions. In conclusion, both glucose and GDP content in PD fluids have systemic impact on the lifespan and neuronal integrity of C. elegans. Detoxification of reactive metabolites by GLO1 overexpression was sufficient to protect lifespan, neuronal integrity and neuronal function in a low-GDP environment. These data emphasize the relevance of the GLO1 detoxifying pathway as a potential therapeutic target in the treatment of reactive metabolite-mediated pathologies.

Towards a Model of Reactive-Cracking: the Role of Reactions, Elasticity and Surface Energy Driven Flow in Poro-elastic Media

NASA Astrophysics Data System (ADS)

Evans, O.; Spiegelman, M. W.; Wilson, C. R.; Kelemen, P. B.

2016-12-01

Many critical processes can be described by reactive fluid flow in brittle media, including hydration/alteration of oceanic plates near spreading ridges, chemical weathering, and dehydration/decarbonation of subducting plates. Such hydration reactions can produce volume changes that may induce stresses large enough to drive fracture in the rock, in turn exposing new reactive surface and modifying the permeability. A better understanding of this potentially rich feedback could also be critical in the design of engineered systems for geologic carbon sequestration. To aid understanding of these processes we have developed a macroscopic continuum description of reactive fluid flow in an elastically deformable porous media. We explore the behaviour of this model by considering a simplified hydration reaction (e.g. olivine + H20 -> serpentine + brucite). In a closed system, these hydration reactions will continue to consume available fluids until the permeability reaches zero, leaving behind it a highly stressed residuum. Our model demonstrates this limiting behaviour, and that the elastic stresses generated are large enough to cause failure/fracture of the host rock. Whilst it is understood that `reactive fracture' is an important mechanism for the continued evolution of this process, it is also proposed that imbibition/surface energy driven flow may play a role. Through a simplified set of computational experiments, we investigate the relative roles of elasticity and surface energy in both a non-reactive purely poro-elastic framework, and then in the presence of reaction. We demonstrate that surface energy can drive rapid diffusion of porosity, thus allowing the reaction to propagate over larger areas. As we expect both surface energy and fracture/failure to be of importance in these processes, we plan to integrate the current model into one that allows for fracture once critical stresses are exceeded.

High on-clopidogrel treatment platelet reactivity in Thai patients with chronic stable angina scheduled for percutaneous coronary intervention.

PubMed

Phankingthongkum, Rewat; Panchavinnin, Pradit; Chinthammitr, Yingyong; Tresukosol, Damras; Chotinaiwattarakul, Chunhakasem; Tungsubutra, Wiwun; Wongpraparut, Nattawut; Kitrattana, Bussakorn; Leewanun, Piyachat

2013-05-01

To determine the prevalence, clinical profile, and risk factors of high on-clopidogrel treatment platelet reactivity in Thai patients with chronic stable angina scheduled for percutaneous coronary intervention. The patients were prospectively recruited from the consecutive patients undergoing coronary angiography and planned for elective percutaneous coronary intervention (PCI). Ten ml of blood samples were cautiously drawn from the antecubital vein of the patients to determine the hemoglobin and platelet count. Platelet aggregation test was performed by light transmittance aggregometry using platelet-rich plasma. Platelets were stimulated with 5 microM adenosine diphosphate (ADP). Platelet aggregation was expressed as the maximal percent change in light transmittance from baseline. High on-clopidogrel treatment platelet reactivity was defined as post treatment maximal platelet aggregation > 46% with 5 micromol/l ADP used as agonist. The present study consecutively enrolled two hundred four patients diagnosed with chronic stable angina planned for PCI. Seventy-nine patients demonstrated the high on-clopidogrel treatment platelet reactivity (38.7%). Among these patients, 48% were men with a mean age of 66 years. Diabetes mellitus and chronic kidney disease were detected in 34.2%. Original clopidogrel (Plavix) was prescribed in 72% of the patients and 28% received generic clopidogrel (Apolets). The prevalence of high on-clopidogrel treatment platelet reactivity increased in the older patients, patients with CKD and patients receiving angiotensin receptor blockers (ARB). However from multivariate analysis, none of the risk factors, including age, BMl, diabetes mellitus, smoking, CKD, ARB use, and type of clopidogrel (Plavix versus Apolets) had a statistically significant association with the high on-clopidogrel treatment platelet reactivity. The prevalence of high on-clopidogrel treatment platelet reactivity in the present study was 38.7%. No significant association

Reactive transport model of growth and methane production by high-temperature methanogens in hydrothermal regions of the subseafloor

NASA Astrophysics Data System (ADS)

Stewart, L. C.; Algar, C. K.; Topçuoğlu, B. D.; Fortunato, C. S.; Larson, B. I.; Proskurowski, G. K.; Butterfield, D. A.; Vallino, J. J.; Huber, J. A.; Holden, J. F.

2014-12-01

Hydrogenotrophic methanogens are keystone high-temperature autotrophs in deep-sea hydrothermal vents and tracers of habitability and biogeochemical activity in the hydrothermally active subseafloor. At Axial Seamount, nearly all thermophilic methanogens are Methanothermococcus and Methanocaldococcus species, making this site amenable to modeling through pure culture laboratory experiments coupled with field studies. Based on field microcosm incubations with 1.2 mM, 20 μM, or no hydrogen, the growth of methanogens at 55°C and 80°C is limited primarily by temperature and hydrogen availability, with ammonium amendment showing no consistent effect on total methane output. The Arrhenius constants for methane production by Methanocaldococcus jannaschii (optimum 82°C) and Methanothermococcus thermolithotrophicus (optimum 65°C) were determined in pure culture bottle experiments. The Monod constants for hydrogen concentration were measured by growing both organisms in a 2-liter chemostat at two dilution rates; 55°C, 65°C and 82°C; and variable hydrogen concentrations. M. jannaschii showed higher ks and Vmax constants than M. thermolithotrophicus. In the field, hydrogen and methane concentrations in hydrothermal end-member and low-temperature diffuse fluids were measured, and the concentrations of methanogens that grow at 55°C and 80°C in diffuse fluids were determined using most-probable-number estimates. Methane concentration anomalies in diffuse fluids relative to end-member hydrothermal concentrations and methanogen cell concentrations are being used to constrain a 1-D reactive transport model using the laboratory-determined Arrhenius and Monod constants for methane production by these organisms. By varying flow path length and subseafloor cell concentrations in the model, our goal is to determine solutions for the potential depth of the subseafloor biosphere coupled with the amount of methanogenic biomass it contains.

High Order Approximations for Compressible Fluid Dynamics on Unstructured and Cartesian Meshes

NASA Technical Reports Server (NTRS)

Barth, Timothy (Editor); Deconinck, Herman (Editor)

1999-01-01

The development of high-order accurate numerical discretization techniques for irregular domains and meshes is often cited as one of the remaining challenges facing the field of computational fluid dynamics. In structural mechanics, the advantages of high-order finite element approximation are widely recognized. This is especially true when high-order element approximation is combined with element refinement (h-p refinement). In computational fluid dynamics, high-order discretization methods are infrequently used in the computation of compressible fluid flow. The hyperbolic nature of the governing equations and the presence of solution discontinuities makes high-order accuracy difficult to achieve. Consequently, second-order accurate methods are still predominately used in industrial applications even though evidence suggests that high-order methods may offer a way to significantly improve the resolution and accuracy for these calculations. To address this important topic, a special course was jointly organized by the Applied Vehicle Technology Panel of NATO's Research and Technology Organization (RTO), the von Karman Institute for Fluid Dynamics, and the Numerical Aerospace Simulation Division at the NASA Ames Research Center. The NATO RTO sponsored course entitled "Higher Order Discretization Methods in Computational Fluid Dynamics" was held September 14-18, 1998 at the von Karman Institute for Fluid Dynamics in Belgium and September 21-25, 1998 at the NASA Ames Research Center in the United States. During this special course, lecturers from Europe and the United States gave a series of comprehensive lectures on advanced topics related to the high-order numerical discretization of partial differential equations with primary emphasis given to computational fluid dynamics (CFD). Additional consideration was given to topics in computational physics such as the high-order discretization of the Hamilton-Jacobi, Helmholtz, and elasticity equations. This volume consists

Design of a High Voltage Power Supply Providing a Force Field for a Fluid Experiment

NASA Astrophysics Data System (ADS)

Herty, Frank

2005-05-01

As part of the GeoFlow fluid experiment an ac high voltage power supply (HVPS) is used to establish high electrical fields on fluids based on silicon oil. The non- conductive fluid is encapsulated between two spherical electrodes. This experiment cell assembly acts essentially as a capacitive load.The GeoFlow HVPS is an integrated ac high voltage source capable to provide up to 10kVRMS on capacitive loads up to 100pF.This paper presents major design challenges and solutions regarding the high voltage transformer and its driver electronics. Particular high voltage problems like corona effects and dielectric losses are discussed and countermeasures are presented.

Development and pilot validation of a sensory reactivity scale for adults with high functioning autism spectrum conditions: Sensory Reactivity in Autism Spectrum (SR-AS).

PubMed

Elwin, Marie; Schröder, Agneta; Ek, Lena; Kjellin, Lars

2016-01-01

Unusual reactions to sensory stimuli are experienced by 90-95% of people with an autism spectrum condition (ASC). Self-reported sensory reactivity in ASC has mainly been measured with generic questionnaires developed and validated on data from the general population. Interest in sensory reactivity in ASC increased after the inclusion of hyper- and hypo-reactivity together with unusual sensory interest as diagnostic markers of ASC in the DSM-5. To develop and pilot validate a self-report questionnaire designed from first-hand descriptions of the target group of adults diagnosed with high functioning ASC. Psychometric properties of the questionnaire were evaluated on a sample of participants with ASC diagnoses (N = 71) and a random sample from the general population (N = 162). The Sensory Reactivity in Autism Spectrum (SR-AS is intended to be used as a screening tool in diagnostic processes with adults and for support in adapting compensating strategies and environmental adjustments. The internal consistency was high for both the SR-AS and its subscales. The total scale Cronbach's alpha was 0.96 and the subscales alphas were ≥ 0.80. Confirmatory factor analysis (CFA) showed best fit for a four-factor model of inter-correlated factors: hyper and hypo-reactivity, strong sensory interest and a sensory/motor factor. The questionnaire discriminated well between ASC-diagnosed participants and participants from the general population. The SR-AS displayed good internal consistency and discriminatory power and promising factorial validity.

Serpentinization as a reactive transport process: The brucite silicification reaction

NASA Astrophysics Data System (ADS)

Tutolo, B. M.; Luhmann, A. J.; Tosca, N. J.; Seyfried, W. E., Jr.

2017-12-01

Serpentinization plays a fundamental role in the biogeochemical and tectonic evolution of the Earth and perhaps many other rocky planetary bodies. Yet, geochemical models still fail to produce accurate predictions of the various modes of serpentinization, which limits our ability to predict a variety of related geological phenomena over many spatial and temporal scales. Here, we utilize kinetic and reactive transport experiments to parameterize the brucite silicification reaction and provide fundamental constraints on SiO2 transport during serpentinization. We show that, at temperatures characteristic of the sub-seafloor at the serpentinite-hosted Lost City Hydrothermal Field, the assembly of Si tetrahedra onto MgOH2 (i.e., brucite) surfaces is a rate-limiting elementary reaction in the production of serpentine and/or talc from olivine. Moreover, a kinetic rate law extracted from our laboratory experiments shows that this reaction is exponentially dependent on the activity of aqueous silica (aSiO2(aq)), such that its rate is orders of magnitude slower near-equilibrium than it is far-from-equilibrium. Calculations performed with this rate law demonstrate that both brucite and Si are surprisingly persistent in serpentinizing environments, leading to elevated Si concentrations in fluids that can be transported over comparatively large distances without equilibrating with brucite. Moreover, applying this rate law to an open-system reactive transport experiment indicates that advection, preferential flow pathways, and reactive surface area armoring can diminish the net rate of Si uptake resulting from this reaction even further. Because brucite silicification is a fundamentally rate-limiting elementary reaction for the production of both serpentine and talc from forsterite, our new constraints are applicable across the many environments where serpentinization occurs. The unexpected but highly consequential behavior of this simple reaction emphasizes the need for

Investigation of the capture of magnetic particles from high-viscosity fluids using permanent magnets

PubMed Central

Garraud, A.; Velez, C.; Shah, Y.; Garraud, N.; Kozissnik, B.; Yarmola, E. G.; Allen, K. D.; Dobson, J.; Arnold, D. P.

2015-01-01

Goal This paper investigates the practicality of using a small, permanent magnet to capture magnetic particles out of high-viscosity biological fluids, such as synovial fluid. Methods Numerical simulations are used to predict the trajectory of magnetic particles toward the permanent magnet. The simulations are used to determine a “collection volume” with a time-dependent size and shape, which determines the number of particles that can be captured from the fluid in a given amount of time. Results The viscosity of the fluid strongly influences the velocity of the magnetic particles towards the magnet, hence the collection volume after a given time. In regards to the design of the magnet, the overall size is shown to most strongly influence the collection volume in comparison to the magnet shape or aspect ratio. Conclusion Numerical results showed good agreement with in vitro experimental magnetic collection results. Significance In the long-term, this work aims to facilitate optimization of the collection of magnetic particle-biomarker conjugates from high-viscosity biological fluids without the need to remove the fluid from a patient. PMID:26208261

Investigation of the Capture of Magnetic Particles From High-Viscosity Fluids Using Permanent Magnets.

PubMed

Garraud, Alexandra; Velez, Camilo; Shah, Yash; Garraud, Nicolas; Kozissnik, Bettina; Yarmola, Elena G; Allen, Kyle D; Dobson, Jon; Arnold, David P

2016-02-01

This paper investigates the practicality of using a small, permanent magnet to capture magnetic particles out of high-viscosity biological fluids, such as synovial fluid. Numerical simulations are used to predict the trajectory of magnetic particles toward the permanent magnet. The simulations are used to determine a "collection volume" with a time-dependent size and shape, which determines the number of particles that can be captured from the fluid in a given amount of time. The viscosity of the fluid strongly influences the velocity of the magnetic particles toward the magnet, hence, the collection volume after a given time. In regards to the design of the magnet, the overall size is shown to most strongly influence the collection volume in comparison to the magnet shape or aspect ratio. Numerical results showed good agreement with in vitro experimental magnetic collection results. In the long term, this paper aims to facilitate optimization of the collection of magnetic particle-biomarker conjugates from high-viscosity biological fluids without the need to remove the fluid from a patient.

Development of high gradient magnetic separation system for removing the metallic wear debris to be present in highly viscous fluid

NASA Astrophysics Data System (ADS)

Hayashi, S.; Mishima, F.; Akiyama, Y.; Nishijima, S.

2010-11-01

In the industrial plants processing highly viscous fluid such as foods or industrial materials, there is an issue of contamination by metallic wear debris originating from pipe of manufacturing line. It is necessary to remove the metallic wear debris in highly viscous fluid, since these debris causes quality loss. In this study, we developed a high gradient magnetic separation system by using superconducting magnet to remove the metallic wear debris. The particle trajectory simulation and the magnetic separation experiment were conducted with polyvinyl alcohol as a model material. As a result, ca. 100% and 92.2% of the separation efficiency was achieved respectively for the highly viscous fluid of 1 Pa s and 6 Pa s in viscosity, with 14 and 30 mesh magnetic filters.

Cardiac troponin T determination by a highly sensitive assay in postmortem serum and pericardial fluid.

PubMed

González-Herrera, Lucas; Valenzuela, Aurora; Ramos, Valentín; Blázquez, Antonia; Villanueva, Enrique

2016-06-01

The main objective of this study was to test, for the first time, a highly sensitive cardiac troponin T (cTnThs) assay in postmortem serum and pericardial fluid and to evaluate cardiac troponin T (cTnT) levels and their stability after death at different postmortem intervals, in an attempt to determine the viability of the cTnThs assay in the postmortem diagnosis of the cause of death. cTnT levels were determined in serum and pericardial fluid samples taken from 58 cadavers at known postmortem intervals, whose causes of death were categorized into the following groups: (1) sudden cardiac deaths, (2) multiple trauma, (3) mechanical asphyxia, and (4) other natural deaths. cTnT was determined by inmunoassay, using the Troponin T highly sensitive STAT assay (Roche(®)). Average cTnT levels measured by a highly sensitive assay in postmortem serum were markedly higher than clinical serum levels. Moreover, similar results, higher cTnT levels in postmortem pericardial fluid, were obtained when compared to levels found in pericardial fluid taken from two living patients during coronary artery bypass surgery. cTnT levels in both postmortem fluids remained stable for up to 34 h after death. No differences in cTnT levels in either postmortem fluid by sex and age were detected. Levels of cTnT found in pericardial fluid in the other natural deaths group were significantly lower than the cTnT levels found in that postmortem fluid from any of the other causes of death groups. It is therefore reasonable to conclude that determination of cTnT by a highly sensitive assay in pericardial fluid can provide forensic pathologists with a complementary test to the diagnosis of cause of death.

Influence of the Fluid on the Parameters and Limits of Bubble Detonation

NASA Astrophysics Data System (ADS)

Pinaev, A. V.; Prokhorov, E. S.

2017-12-01

The compression and inflammation of reactive gas bubbles in bubble detonation waves have been studied, and the considerable influence of the fluid (liquid or vapor) on the detonation parameters has been found. It has been shown numerically that the final values of the pressure and temperature significantly decrease if the temperature dependence of the adiabatic index is taken into account at the compression stage. The parameters of reactive gas combustion products in the bubble have been calculated in terms of an equilibrium model, and the influence of the fluid that remains in the bubble in the form of microdroplets and vapor on these parameters has been investigated.

P-wave velocity anisotropy related to sealed fractures reactivation tracing the structural diagenesis in carbonates

NASA Astrophysics Data System (ADS)

Matonti, C.; Guglielmi, Y.; Viseur, S.; Garambois, S.; Marié, L.

2017-05-01

Fracture properties are important in carbonate reservoir characterization, as they are responsible for a large part of the fluid transfer properties at all scales. It is especially true in tight rocks where the matrix transfer properties only slightly contribute to the fluid flow. Open fractures are known to strongly affect seismic velocities, amplitudes and anisotropy. Here, we explore the impact of fracture evolution on the geophysical signature and directional Vp anisotropy of fractured carbonates through diagenesis. For that purpose, we studied a meter-scale, parallelepiped quarry block of limestone using a detailed structural and diagenetic characterization, and numerous Vp measurements. The block is affected by two en-échelon fracture clusters, both being formed in opening mode (mode 1) and cemented, but only one being reactivated in shear. We compared the diagenetic evolution of the fractures, which are almost all 100% filled with successive calcite cements, with the P-wave velocities measured across this meter-scale block of carbonate, which recorded the tectonic and diagenetic changes of a South Provence sedimentary basin. We found that a directional Vp anisotropy magnitude as high as 8-16% correlates with the reactivated fractures' cluster dip angle, which is explained by the complex filling sequence and softer material present inside the fractures that have been reactivated during the basin's tectonic inversion. We show that although a late karstification phase preferentially affected these reactivated fractures, it only amplified the pre-existing anisotropy due to tectonic shear. We conclude that Vp anisotropy measurements may help to identify the fracture sealing/opening processes associated with polyphased tectonic history, the anisotropy being independent of the current stress-state. This case shows that velocity anisotropies induced by fractures resulted here from a cause that is different from how these features have often been interpreted

High fluid pressure and triggered earthquakes in the enhanced geothermal system in Basel, Switzerland

NASA Astrophysics Data System (ADS)

Terakawa, T.; Miller, S. A.; Deichmann, N.

2011-12-01

We estimate the pore fluid pressure field of the stimulated region during the fluid injection experiment in Basel, Switzerland by analyzing 118 well-constrained focal mechanisms. This technique, termed focal mechanism tomography (FMT), uses the orientations of the slip planes within the prevailing regional stress field as indicator of the fluid pressure along the plane at the time of slip. Elevated pore fluid pressures were concentrated within 500 m of the open hole section, and we find average earthquake triggering excess pressures of about 10MPa, with a peak value of 19.3 MPa, consistent with the known wellhead pressure applied at the borehole. Our results demonstrate that FMT is a robust approach, being validated at the macroscopic scale of the Basel stimulation experiment. Over-pressurized fluids induced many small events (M < 3) along faults unfavourably-oriented relative to the tectonic stress pattern, while larger events tended to occur along optimally-oriented faults. This suggests that small-scale hydraulic networks, developed from the high pressure stimulation, interact to load (hydraulically isolated) high strength bridges that produce the larger events. The triggering pore fluid pressures are substantially higher than that predicted from a linear pressure diffusion process from the source boundary, showing that the system is highly permeable along flow paths, allowing fast pressure diffusion to the boundaries of the stimulated region.

Occurrence of tetrodotoxin-binding high molecular weight substances in the body fluid of shore crab (Hemigrapsus sanguineus).

PubMed

Shiomi, K; Yamaguchi, S; Kikuchi, T; Yamamori, K; Matsui, T

1992-12-01

The shore crab (Hemigrapsus sanguineus) is highly resistant to tetrodotoxin (TTX) although it contains no detectable amount of TTX (less than 5 MU/g, where 1 MU is defined as the amount of TTX killing a 20 g mouse in 30 min). Its body fluid was examined for neutralizing effects against the lethal activity of TTX. When the mixture of the body fluid and TTX was injected i.p. into mice, the lethal activity of TTX was significantly reduced; 1 ml of the body fluid was evaluated to neutralize 3.6-4.0 MU of TTX. Higher neutralizing activity (7.2-12.5 MU/ml of the body fluid) was exhibited by i.v. administration of the body fluid into mice before or after i.p. challenge of TTX. The lethal effect of paralytic shellfish poisons was not counteracted by the body fluid. Analysis by gel filtration on Sepharose 6B revealed that the body fluid contained TTX-binding high mol. wt substances (> 2,000,000) responsible for the neutralizing activity of the body fluid against TTX, which accounts for the high resistibility of the crab to TTX. When the crude toxin extracted from the liver of puffer (Takifugu niphobles) was mixed with the body fluid and chromatographed on Sepharose 6B, almost pure TTX was obtained from the fractions containing the TTX-binding high mol. wt substances, suggesting that the TTX-binding high mol. wt substances could be useful in purification of TTX from biological samples.

Modeling Fluid Flow and Microbial Reactions in the Peru Accretionary Complex

NASA Astrophysics Data System (ADS)

Bekins, B. A.; Matmon, D.

2002-12-01

Accretionary complexes are sites where sediment compaction and deeper reactions drive large-scale flow systems that can affect global solute budgets. Extensive modeling and drilling studies have elucidated the origin of the fluids, pore pressures, duration of flow, and major flow paths in these settings. An important research goal is to quantify the effect of these flow systems on global chemical budgets of reactive solutes such as carbon. The Peru margin represents an end member setting that can serve as a basis to extend the results to other margins. The sediments are relatively high in organic carbon with an average value of 2.6%. The subduction rate at ~9 cm/yr and taper angle at 14-17° are among the largest in the world. Recent microbial studies on Ocean Drilling Program Leg 201 at the Peru accretionary margin provide many key elements needed to quantify the processes affecting organic carbon in an accretionary complex. Pore water chemistry data from Site 1230 located in the Peru accretionary prism indicate that sulfate reduction is important in the top 8 mbsf. Below this depth, methanogenesis is the dominant process and methane concentrations are among the highest measured at any site on Leg 201. The presence of high methane concentrations at shallow depths suggests that methane is transported upward in the prism by fluid flow. Measurements of in-situ pore pressures and temperatures also support the presence of upward fluid flow. A single in-situ pressure measurement at ~100 mbsf indicated an overpressure of 0.14 MPa. For a reasonable formation permeability of ~ 10-16 m2, the measured overpressure is adequate to produce flow at a rate of ~5 mm/yr. This rate is comparable to previous model estimates for flow rates in the Peru accretionary prism. In addition, curvature in the downhole temperature profile can best be explained by upward fluid flow of 1-10 mm/yr. These data are used to constrain a two-dimensional coupled fluid flow and reactive transport model

An Analytical Model for Assessing Stability of Pre-Existing Faults in Caprock Caused by Fluid Injection and Extraction in a Reservoir

NASA Astrophysics Data System (ADS)

Wang, Lei; Bai, Bing; Li, Xiaochun; Liu, Mingze; Wu, Haiqing; Hu, Shaobin

2016-07-01

Induced seismicity and fault reactivation associated with fluid injection and depletion were reported in hydrocarbon, geothermal, and waste fluid injection fields worldwide. Here, we establish an analytical model to assess fault reactivation surrounding a reservoir during fluid injection and extraction that considers the stress concentrations at the fault tips and the effects of fault length. In this model, induced stress analysis in a full-space under the plane strain condition is implemented based on Eshelby's theory of inclusions in terms of a homogeneous, isotropic, and poroelastic medium. The stress intensity factor concept in linear elastic fracture mechanics is adopted as an instability criterion for pre-existing faults in surrounding rocks. To characterize the fault reactivation caused by fluid injection and extraction, we define a new index, the "fault reactivation factor" η, which can be interpreted as an index of fault stability in response to fluid pressure changes per unit within a reservoir resulting from injection or extraction. The critical fluid pressure change within a reservoir is also determined by the superposition principle using the in situ stress surrounding a fault. Our parameter sensitivity analyses show that the fault reactivation tendency is strongly sensitive to fault location, fault length, fault dip angle, and Poisson's ratio of the surrounding rock. Our case study demonstrates that the proposed model focuses on the mechanical behavior of the whole fault, unlike the conventional methodologies. The proposed method can be applied to engineering cases related to injection and depletion within a reservoir owing to its efficient computational codes implementation.

Reactive oxygen species modulator 1, a novel protein, combined with carcinoembryonic antigen in differentiating malignant from benign pleural effusion.

PubMed

Chen, Xianmeng; Zhang, Na; Dong, Jiahui; Sun, Gengyun

2017-05-01

The differential diagnosis of malignant pleural effusion and benign pleural effusion remains a clinical problem. Reactive oxygen species modulator 1 is a novel protein overexpressed in various human tumors. The objective of this study was to evaluate the diagnostic value of joint detection of reactive oxygen species modulator 1 and carcinoembryonic antigen in the differential diagnosis of malignant pleural effusion and benign pleural effusion. One hundred two consecutive patients with pleural effusion (including 52 malignant pleural effusion and 50 benign pleural effusion) were registered in this study. Levels of reactive oxygen species modulator 1 and carcinoembryonic antigen were measured by enzyme-linked immunosorbent assay and radioimmunoassay, respectively. Results showed that the concentrations of reactive oxygen species modulator 1 both in pleural fluid and serum of patients with malignant pleural effusion were significantly higher than those of benign pleural effusion (both p < 0.05). The diagnostic sensitivity and specificity of pleural fluid reactive oxygen species modulator 1 were 61.54% and 82.00%, respectively, with the optimized cutoff value of 589.70 pg/mL. However, the diagnostic sensitivity and specificity of serum reactive oxygen species modulator 1 were only 41.38% and 86.21%, respectively, with the cutoff value of 27.22 ng/mL, indicating that serum reactive oxygen species modulator 1 may not be a good option in the differential diagnosis of malignant pleural effusion and benign pleural effusion. The sensitivity and specificity of pleural fluid carcinoembryonic antigen were 69.23% and 88.00%, respectively, at the cutoff value of 3.05 ng/mL, while serum carcinoembryonic antigen were 80.77% and 72.00% at the cutoff value of 2.60 ng/mL. The sensitivity could be raised to 88.17% in parallel detection of plural fluid reactive oxygen species modulator 1 and carcinoembryonic antigen concentration, and the specificity could be improved to 97

High-dose catecholamine treatment decreases polymorphonuclear leukocyte phagocytic capacity and reactive oxygen production.

PubMed Central

Wenisch, C; Parschalk, B; Weiss, A; Zedwitz-Liebenstein, K; Hahsler, B; Wenisch, H; Georgopoulos, A; Graninger, W

1996-01-01

Flow cytometry was used to study phagocytic function (uptake of fluorescein isothiocyanate-labeled bacteria) and release of reactive oxygen products (dihydrorhodamine 123 converted to rhodamine 123) following phagocytosis by neutrophil granulocytes of heparinized whole blood treated with adrenaline, noradrenaline, dopamine, dobutamine, or orciprenaline. Reduced neutrophil phagocytosis and reactive oxygen production were seen at 12 micrograms of adrenaline per liter (72% each compared with control values); at 120 micrograms of noradrenaline (72% each), dobutamine (83 and 80%, respectively), and orciprenaline (81 and 80%, respectively) per liter; and at 100 micrograms of dopamine per liter (66 and 70%) (P < 0.05 for all). At these dosages, neutrophil chemotaxis was reduced to < 50% of control values for all catecholamines. Treatment with catecholamines at lower dosages had no significant effect on phagocytosis or generation of reactive oxygen products or chemotaxis. The phagocytic capacity of granulocytes was related to the generation of reactive oxygen products (r = 0.789; P < 0.05). The results demonstrate that catecholamines have a suppressive effect on the response of phagocytic cells to bacterial pathogens at high therapeutic levels in blood. PMID:8807207

Amniotic fluid: the use of high-dimensional biology to understand fetal well-being.

PubMed

Kamath-Rayne, Beena D; Smith, Heather C; Muglia, Louis J; Morrow, Ardythe L

2014-01-01

Our aim was to review the use of high-dimensional biology techniques, specifically transcriptomics, proteomics, and metabolomics, in amniotic fluid to elucidate the mechanisms behind preterm birth or assessment of fetal development. We performed a comprehensive MEDLINE literature search on the use of transcriptomic, proteomic, and metabolomic technologies for amniotic fluid analysis. All abstracts were reviewed for pertinence to preterm birth or fetal maturation in human subjects. Nineteen articles qualified for inclusion. Most articles described the discovery of biomarker candidates, but few larger, multicenter replication or validation studies have been done. We conclude that the use of high-dimensional systems biology techniques to analyze amniotic fluid has significant potential to elucidate the mechanisms of preterm birth and fetal maturation. However, further multicenter collaborative efforts are needed to replicate and validate candidate biomarkers before they can become useful tools for clinical practice. Ideally, amniotic fluid biomarkers should be translated to a noninvasive test performed in maternal serum or urine.

Evaluation of commercial multi-drug oral fluid devices to identify 39 new amphetamine-designer drugs.

PubMed

Nieddu, Maria; Burrai, Lucia; Trignano, Claudia; Boatto, Gianpiero

2014-03-01

Recently, the diffusion on the black market of new psychoactive substances not controlled and often sold as 'legal highs', is exponentially increasing in Europe. Generally, the first analysis for these drugs involves an immunoassay screening in urine or plasma. Actually, there is growing interest in the use of oral fluid (OF) as alternative specimen over conventional biological fluids for drug testing, because of the significant advantages, as a non-invasive collection under direct observation without undue embarrassment or invasion of privacy, and a good correlation with plasma analytical data. Few assays have been developed for detection of new psychoactive compounds in biological samples, so it is important to investigate how they may or may not react in pre-existing commercial immunoassays. In this paper, two different multi-drugs oral fluid screen devices (OFDs) (Screen® Multi-Drug OFD and GIMA One Step Multi-Line Screen Test OFD) were evaluated to determine the cross-reactivity of thirty-nine new amphetamine designer drugs, including twelve substances officially recognized as illicit by italian legislation. Cross-reactivity towards most drugs analyzed was <1 in assays targeting amphetamine (AMP) or methamphetamine (MET). Only two (p-methoxyamphetamine and p-methoxymethamphetamine) of all tested amphetamines gave a positive result. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Changes in body fluid compartments on re-induction to high altitude and effect of diuretics

NASA Astrophysics Data System (ADS)

Singh, M. V.; Rawal, S. B.; Tyagi, A. K.; Bhagat, Maj J. K.; Parshad, R.; Divekar, H. M.

1988-03-01

Studies were carried out in 29 healthy young adults in the Indian Army stationed in the plains and posted at an elevation of 3500 m for more than 6 months. After exposure to a low elevation in Delhi (260 m) for 3 weeks they were reinduced to a height of 3500 m. The subjects were divided into three groups, each of which was treated with either placebo or acetazolamide or spironolactone. The drug treatment was started immediately after their landing at high altitude and continued for 2 days only. Total body water, extracellular fluid, intracellular fluid, plasma volume, blood pH, PaO2, PaCO2 and blood viscosity were determined on exposure at Delhi and on re-induction to high altitude. Plasma volume was increased after the descent from high altitude and remained high for up to 21 day's study. This increased plasma volume may have some significance in the pathogenesis of pulmonary oedema. Total body water and intracellular fluid content were increased at 260 m elevation, while extracellular fluid decreased. On re-induction there was a decrease in total body water with no change in the extracellular fluid content.

Reactive transport in fractured porous media

NASA Astrophysics Data System (ADS)

Adler, P.; Jasinski, L.; Thovert, J.-F.; Mourzenko, V. V.

2012-04-01

Reactive flow through geological formations occurs in many situations due to human intervention or during natural processes. For instance, chemical dissolution and precipitation play a major role in diagenesis or in the formation of karsts. The quantitative description of the injection of a reacting fluid from a well into a fractured porous medium is also a subject of high interest. It can be provoked, as in the acidization stimulation technique for increasing well productivity, or accidental, in CO2 sequestration. Ideally, one wishes to analyze the improvements or damages caused by the fluid to the well itself and to its immediate surroundings. To this end, a coupled system of equations has to be solved. It includes the description of the flow in the porous matrix and in the fracture network by Darcy-like equations, and the description of the reactive solute transport and of the reactions which occur in the two structures. In addition, constitutive equations are required for the evolution of these two structures, such as evolution laws for permeability and reactivity as functions of porosity. Our discrete fracture numerical model involves three major steps. First, an unstructured tetrahedral mesh of the fractures and of the porous matrix is built. Second, the Darcy equations are discretized and solved, in a finite volume formulation. Third, the evolution of the solute concentration has to be calculated. This is the most difficult point if one wants to avoid numerical diffusion and accurately describe the transfers between the fractures and the matrix. A non linear flux limiting scheme of the Superbee type coupled with a systematic use of triple control volumes proved to be the most efficient. Various simple model situations have been considered, for validation purposes or to illustrate some physical points. In particular, it is shown that even when the matrix permeability is small and the flow is predominantly carried by the fracture network, convective exchanges

Reactive flow in fractured porous media

NASA Astrophysics Data System (ADS)

Jasinski, L.; Thovert, J.; Mourzenko, V.; Adler, P. M.

2011-12-01

Reactive flow through geological formations occurs in many situations due to human intervention or during natural processes. For instance, chemical dissolution and precipitation play a major role in diagenesis or in the formation of karsts. The quantitative description of the injection of a reacting fluid from a well into a fractured porous medium is also a subject of high interest. It can be provoked, as in the acidization stimulation technique for increasing well productivity, or accidental, in CO2 sequestration. Ideally, one wishes to analyze the improvements or damages caused by the fluid to the well itself and to its immediate surroundings. To this end, a coupled system of equations has to be solved. It includes the description of the flow in the porous matrix and in the fracture network by Darcy-like equations, and the description of the reactive solute transport and of the reactions which occur in the two structures. In addition, constitutive equations are required for the evolution of these two structures, such as evolution laws for permeability and reactivity as functions of porosity. Our discrete fracture numerical model involves three major steps. First, an unstructured tetrahedral mesh of the fractures and of the porous matrix is built. Second, the Darcy equations are discretized and solved, in a finite volume formulation. Third, the evolution of the solute concentration has to be calculated. This is the most difficult point if one wants to avoid numerical diffusion and accurately describe the transfers between the fractures and the matrix. A non linear flux limiting scheme of the Superbee type coupled with a systematic use of triple control volumes proved to be the most efficient. Various simple model situations have been considered, for validation purposes or to illustrate some physical points. In particular, it is shown that even when the matrix permeability is small and the flow is predominantly carried by the fracture network, convective exchanges

High gliding fluid power generation system with fluid component separation and multiple condensers

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

Mahmoud, Ahmad M; Lee, Jaeseon; Radcliff, Thomas D

2014-10-14

An example power generation system includes a vapor generator, a turbine, a separator and a pump. In the separator, the multiple components of the working fluid are separated from each other and sent to separate condensers. Each of the separate condensers is configured for condensing a single component of the working fluid. Once each of the components condense back into a liquid form they are recombined and exhausted to a pump that in turn drives the working fluid back to the vapor generator.

Reactivity change of IgE to buckwheat protein treated with high-pressure and enzymatic hydrolysis.

PubMed

Lee, Chaeyoon; In, Sooyeon; Han, Youngshin; Oh, Sangsuk

2016-04-01

Buckwheat is a popular food material in eastern Asian countries that can cause allergenic response. This study was conducted to evaluate the effects of hydrolysis with papain and high-pressure (HP) treatment of buckwheat protein (BWP) on reactivity of immunoglobulin E (IgE) and its secondary structure. Reactivity of IgE was examined by enzyme-linked immunosorbent assay (ELISA) with serum samples from 16 patients allergic to buckwheat. Reactivity of IgE to hydrolysate of BWP with papain showed a maximum decrease of 79.8%. After HP treatment at 600 MPa for 1 min, reactivity of IgE to BWP decreased by up to 55.1%. When extracted, BWP was hydrolyzed with papain overnight following HP treatment at 600 MPa which the reactivity of IgE decreased significantly by up to 87.1%. Significant changes in secondary structure of BWP were observed by circular dichroism (CD) analysis after hydrolysis with papain following HP treatment. Reduction of reactivity of IgE showed a correlation with changes in secondary structure of BWP, which may cause changes in conformational epitopes. This suggests the possibility of decreasing the reactivity of IgE to BWP using combined physical and enzymatic treatments. © 2015 Society of Chemical Industry.

COST ANALYSIS OF PERMEABLE REACTIVE BARRIERS FOR REMEDIATION OF GROUND WATER

EPA Science Inventory

ABSTRACT

Permeable reactive barriers (PRB's) are an emerging, alternative in-situ approach for remediating contaminated groundwater that combine subsurface fluid flow management with a passive chemical treatment zone. PRB's are a potentially more cost effective treatment...

Reactive Fluid Flow and Applications to Diagenesis, Mineral Deposits, and Crustal Rocks

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

Rye, Danny M.; Bolton, Edward W.

2002-11-04

The objective is to initiate new: modeling of coupled fluid flow and chemical reactions of geologic environments; experimental and theoretical studies of water-rock reactions; collection and interpretation of stable isotopic and geochemical field data at many spatial scales of systems involving fluid flow and reaction in environments ranging from soils to metamorphic rocks. Theoretical modeling of coupled fluid flow and chemical reactions, involving kinetics, has been employed to understand the differences between equilibrium, steady-state, and non-steady-state behavior of the chemical evolution of open fluid-rock systems. The numerical codes developed in this project treat multi-component, finite-rate reactions combined with advective andmore » dispersive transport in multi-dimensions. The codes incorporate heat, mass, and isotopic transfer in both porous and fractured media. Experimental work has obtained the kinetic rate laws of pertinent silicate-water reactions and the rates of Sr release during chemical weathering. Ab-initio quantum mechanical techniques have been applied to obtain the kinetics and mechanisms of silicate surface reactions and isotopic exchange between water and dissolved species. Geochemical field-based studies were carried out on the Wepawaug metamorphic schist, on the Irish base-metal sediment-hosted ore system, in the Dalradian metamorphic complex in Scotland, and on weathering in the Columbia River flood basalts. The geochemical and isotopic field data, and the experimental and theoretical rate data, were used as constraints on the numerical models and to determine the length and time scales relevant to each of the field areas.« less

High-pressure cell for neutron reflectometry of supercritical and subcritical fluids at solid interfaces

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

Carmichael, Justin R; Rother, Gernot; Browning, Jim

2012-01-01

A new high-pressure cell design for use in neutron reflectometry (NR) for pressures up to 50 MPa and a temperature range of 300 473 K is described. The cell design guides the neutron beam through the working crystal without passing through additional windows or the bulk fluid, which provides for a high neutron transmission, low scattering background, and low beam distortion. The o-ring seal is suitable for a wide range of subcritical and supercritical fluids and ensures high chemical and pressure stability. Wafers with a diameter of 5.08 cm (2 in.) and 5 mm or 10 mm thickness can bemore » used with the cells, depending on the required pressure and momentum transfer range. The fluid volume in the sample cell is very small at about 0.1 ml, which minimizes scattering background and stored energy. The cell design and pressure setup for measurements with supercritical fluids are described. NR data are shown for silicon/silicon oxide and quartz wafers measured against air and subsequently within the high-pressure cell to demonstrate the neutron characteristics of the high-pressure cell. Neutron reflectivity data for supercritical CO2 in contact with quartz and Si/SiO2 wafers are also shown.« less

Development of superconducting high gradient magnetic separation system for highly viscous fluid for practical use

NASA Astrophysics Data System (ADS)

Hayashi, S.; Mishima, F.; Akiyama, Y.; Nishijima, S.

2011-11-01

In the industrial plants processing highly viscous fluid such as foods or industrial products, it is necessary to remove the metallic wear debris originating from pipe in manufacturing line which triggers quality loss. In this study, we developed a high gradient magnetic separation (HGMS) system which consists of superconducting magnet to remove the metallic wear debris. The magnetic separation experiment and the particle trajectory simulation were conducted with polyvinyl alcohol (PVA) as a model material (viscosity coefficient was 10 Pa s, which is 10,000 times higher than that in water). In order to develop a magnetic separation system for practical use, the particle trajectory simulation by using solenoidal superconducting magnet was conducted, and the possibility of the magnetic separation for removing ferromagnetic stainless steel (SUS) particles in highly viscous fluid of 10 Pa s was indicated. Based on the results, the number of filters to obtain required separation efficiency was examined to design the practical separation system.

An earthquake instability model based on faults containing high fluid-pressure compartments

USGS Publications Warehouse

Lockner, D.A.; Byerlee, J.D.

1995-01-01

It has been proposed that large strike-slip faults such as the San Andreas contain water in seal-bounded compartments. Arguments based on heat flow and stress orientation suggest that in most of the compartments, the water pressure is so high that the average shear strength of the fault is less than 20 MPa. We propose a variation of this basic model in which most of the shear stress on the fault is supported by a small number of compartments where the pore pressure is relatively low. As a result, the fault gouge in these compartments is compacted and lithified and has a high undisturbed strength. When one of these locked regions fails, the system made up of the neighboring high and low pressure compartments can become unstable. Material in the high fluid pressure compartments is initially underconsolidated since the low effective confining pressure has retarded compaction. As these compartments are deformed, fluid pressure remains nearly unchanged so that they offer little resistance to shear. The low pore pressure compartments, however, are overconsolidated and dilate as they are sheared. Decompression of the pore fluid in these compartments lowers fluid pressure, increasing effective normal stress and shear strength. While this effect tends to stabilize the fault, it can be shown that this dilatancy hardening can be more than offset by displacement weakening of the fault (i.e., the drop from peak to residual strength). If the surrounding rock mass is sufficiently compliant to produce an instability, slip will propagate along the fault until the shear fracture runs into a low-stress region. Frictional heating and the accompanying increase in fluid pressure that are suggested to occur during shearing of the fault zone will act as additional destabilizers. However, significant heating occurs only after a finite amount of slip and therefore is more likely to contribute to the energetics of rupture propagation than to the initiation of the instability. We present

Fluid injection device for high-pressure systems

NASA Technical Reports Server (NTRS)

Copeland, E. J.; Ward, J. B.

1970-01-01

Screw activated device, consisting of a compressor, shielded replaceable ampules, a multiple-element rubber gland, and a specially constructed fluid line fitting, injects measured amounts of fluids into a pressurized system. It is sturdy and easily manipulated.

High precision Hugoniot measurements on statically pre-compressed fluid helium

NASA Astrophysics Data System (ADS)

Seagle, Christopher T.; Reinhart, William D.; Lopez, Andrew J.; Hickman, Randy J.; Thornhill, Tom F.

2016-09-01

The capability for statically pre-compressing fluid targets for Hugoniot measurements utilizing gas gun driven flyer plates has been developed. Pre-compression expands the capability for initial condition control, allowing access to thermodynamic states off the principal Hugoniot. Absolute Hugoniot measurements with an uncertainty less than 3% on density and pressure were obtained on statically pre-compressed fluid helium utilizing a two stage light gas gun. Helium is highly compressible; the locus of shock states resulting from dynamic loading of an initially compressed sample at room temperature is significantly denser than the cryogenic fluid Hugoniot even for relatively modest (0.27-0.38 GPa) initial pressures. The dynamic response of pre-compressed helium in the initial density range of 0.21-0.25 g/cm3 at ambient temperature may be described by a linear shock velocity (us) and particle velocity (up) relationship: us = C0 + sup, with C0 = 1.44 ± 0.14 km/s and s = 1.344 ± 0.025.

Salivary flow and alpha-amylase: collection technique, duration, and oral fluid type.

PubMed

Beltzer, Emilie K; Fortunato, Christine K; Guaderrama, Melissa M; Peckins, Melissa K; Garramone, Bianca M; Granger, Douglas A

2010-09-01

There has been renewed interest in salivary alpha-amylase (sAA), a surrogate marker of autonomic/sympathetic activity, in biosocial research on stress vulnerability, reactivity, and recovery. This study explored the impact of saliva flow rate on sAA measurement by examining the influence of (1) the technique used to collect oral fluid-synthetic swab, cotton pledget, hydrocellulose microsponge, or passive drool; (2) collection point duration--the length of time the technique is employed (1-5min); and (3) oral fluid type--whole unstimulated saliva (not absorbed by any material) or oral fluid sampled from areas near the parotid, submandibular, or sublingual salivary glands. sAA activity (U/mL) was the highest in oral fluid collected from the parotid and submandibular gland areas. The volume (mL) of oral fluid collected increased, and the activity of sAA (U/mL) decreased, as collection point duration lengthened. The magnitude of these effects varied according to collection technique and oral fluid type. Across all conditions, there were positive correlations (range .70-.88) between sAA activity (U/mL) and sAA output (U/min). Management of these potential sources of measurement error will be essential to ensuring the success of future research on the correlates and concomitants of sAA activity, stress-related reactivity and recovery, and diurnal variation. Copyright 2010 Elsevier Inc. All rights reserved.

GEOCHEMISTRY OF SUBSURFACE REACTIVE BARRIERS FOR REMEDIATION OF CONTAMINATED GROUND WATER

EPA Science Inventory

Reactive barriers that couple subsurface fluid flow with a passive chemical treatment zone are emerging, cost effective approaches for in-situ remediation of contaminated groundwater. Factors such as the build-up of surface precipitates, bio-fouling, and changes in subsurface tr...

Tracing Injection Fluids in Engineered Geothermal Systems

NASA Astrophysics Data System (ADS)

Rose, P. E.; Leecaster, K.; Mella, M.; Ayling, B.; Bartl, M. H.

2011-12-01

The reinjection of produced fluids is crucial to the effective management of geothermal reservoirs, since it provides a mechanism for maintaining reservoir pressures while allowing for the disposal of a toxic byproduct. Tracers are essential to the proper location of injection wells since they are the only known tool for reliably characterizing the flow patterns of recirculated fluids. If injection wells are placed too close to production wells, then reinjected fluids do not have sufficient residence time to extract heat from the reservoir and premature thermal breakthrough results. If injection wells are placed too far away, then the reservoir risks unacceptable pressure loss. Several thermally stable compounds from a family of very detectable fluorescent organic compounds (the naphthalene sulfonates) were characterized and found to be effective for use as geothermal tracers. Through batch-autoclave reactions, their Arrhenius pseudo-first-order decay-rate constants were determined. An analytical method was developed that allows for the laboratory determination of concentrations in the low parts-per-trillion range. Field experiments in numerous geothermal reservoirs throughout the world have confirmed the laboratory findings. Whereas conservative tracers such as the naphthalene sulfonates are effective tools for indicating interwell flow patterns and for measuring reservoir pore volumes, 'reactive' tracers can be used to constrain fracture surface area, which is the effective area for heat extraction. This is especially important for engineered geothermal system (EGS) wells, since reactive tracers can be used to measure fracture surface area immediately after drilling and while the well stimulation equipment is still on site. The reactive properties of these tracers that can be exploited to constrain fracture surface area are reversible sorption, contrasting diffusivity, and thermal decay. Laboratory batch- and flow-reactor experiments in combination with numerical

Enhanced Amendment Delivery to Subsurface Using Shear Thinning Fluid and Aqueous Foam for Metal, Radionuclide, and NAPL Remediation

NASA Astrophysics Data System (ADS)

Zhong, L.; Szecsody, J.; Li, X.; Oostrom, M.; Truex, M.

2010-12-01

In many contamination sites, removal of contaminants by any active remediation efforts is not practical due to the high cost and technological limitations. Alternatively, in situ remediation is expected to be the most important remediation strategy. Delivery of reactive amendment to the contamination zone is essential for the reactions between the contaminants and remedial amendments to proceed in situ. It is a challenge to effectively deliver remedial amendment to the subsurface contamination source areas in both aquifer and vadose zone. In aquifer, heterogeneity induces fluid bypassing the low-permeability zones, resulting in certain contaminated areas inaccessible to the remedial amendment delivered by water injection, thus inhibiting the success of remedial operations. In vadose zone in situ remediation, conventional solution injection and infiltration for amendment delivery have difficulties to achieve successful lateral spreading and uniform distribution of the reactive media. These approaches also tend to displace highly mobile metal and radionuclide contaminants such as hexavalent chromium [Cr(VI)] and technetium (Tc-99), causing spreading of contaminations. Shear thinning fluid and aqueous foam can be applied to enhance the amendment delivery and improve in situ subsurface remediation efficiency under aquifer and vadose zone conditions, respectively. Column and 2-D flow cell experiments were conducted to demonstrate the enhanced delivery and improved remediation achieved by the application of shear thinning fluid and foam injection at the laboratory scale. Solutions of biopolymer xanthan gum were used as the shear thinning delivering fluids. Surfactant sodium lauryl ether sulfate (STEOL CS-330) was the foaming agent. The shear thinning fluid delivery (STFD) considerably improved the sweeping efficiency over a heterogeneous system and enhanced the non-aqueous liquid phase (NAPL) removal. The delivery of amendment into low-perm zones (LPZs) by STFD also

Reactive transport modeling of Li isotope fractionation

NASA Astrophysics Data System (ADS)

Wanner, C.; Sonnenthal, E. L.

2013-12-01

The fractionation of Li isotopes has been used as a proxy for interaction processes between silicate rocks and any kind of fluids. In particular, Li isotope measurements are powerful because Li is almost exclusively found in silicate minerals. Moreover, the two stable Li isotopes, 6Li and 7Li, differ by 17% in mass introducing a large mass dependent isotope fractionation even at high temperature. Typical applications include Li isotope measurements along soil profiles and of river waters to track silicate weathering patterns and Li isotope measurements of geothermal wells and springs to assess water-rock interaction processes in geothermal systems. For this contribution we present a novel reactive transport modeling approach for the simulation of Li isotope fractionation using the code TOUGHREACT [1]. It is based on a 6Li-7Li solid solution approach similar to the one recently described for simulating Cr isotope fractionation [2]. Model applications include the simulation of granite weathering along a 1D flow path as well as the simulation of a column experiment related to an enhanced geothermal system. Results show that measured δ7Li values are mainly controlled by (i) the degree of interaction between Li bearing primary silicate mineral phases (e.g., micas, feldspars) and the corresponding fluid, (ii) the Li isotope fractionation factor during precipitation of secondary mineral phases (e.g., clays), (iii) the Li concentration in primary and secondary Li bearing mineral phases and (iv) the proportion of dissolved Li that adsorbs to negatively charged surfaces (e.g., clays, Fe/Al-hydroxides). To date, most of these parameters are not very well constrained. Reactive transport modeling thus currently has to rely on many assumptions. Nevertheless, such models are powerful because they are the only viable option if individual contributions of all potential processes on the resulting (i.e., measured) Li isotopic ratio have to be quantitatively assessed. Accordingly, we

Sulfur isotopes in Icelandic thermal fluids

NASA Astrophysics Data System (ADS)

Gunnarsson-Robin, Jóhann; Stefánsson, Andri; Ono, Shuhei; Torssander, Peter

2017-10-01

Multiple sulfur isotope compositions of thermal fluids from Iceland were measured in order to evaluate the sources and reactions of sulfur and sulfur isotope fractionation in geothermal systems at Icelandic divergent plate boundaries, characterized by MORB-like basalts. The geothermal systems studied had a wide range of reservoir temperatures of 56-296 °C and Cl concentrations of 18-21,000 ppm. Dissolved sulfide (∑ S- II) and SO4 concentrations in liquid water measured < 0.01-165 ppm and 1.3-300 ppm, respectively, and H2S(g) concentrations in the vapor 4.9-2000 ppm. The δ34S and Δ33S values for different phases and oxidation states were highly variable: δ34S∑ S- II = - 11.6 to 10.5‰ (n = 99), Δ33S∑ S- II = - 0.12 to 0.00‰ (n = 45), δ34SSO4 = - 1.0 to 24.9‰ (n = 125), Δ33SSO4 = - 0.04 to 0.02‰ (n = 50), δ34SH2S(g) = - 2.6 to 5.9‰ (n = 112) and Δ33SH2S(g) = - 0.03 to 0.00‰ (n = 56). The multiple sulfur isotope values of the thermal fluids are interpreted to reflect various sources of sulfur in the fluids, as well as isotope fractionation occurring within the geothermal systems associated with fluid-rock interaction, boiling and oxidation and reduction reactions. The results of isotope geochemical modeling demonstrate that the sources of S- II in the thermal fluid are leaching of basalt (MORB) and seawater SO4 reduction for saline systems with insignificant magma gas input, and that the observed ranges of δ34S and Δ33S for ∑ S- II and H2S(g) reflect isotope fractionation between minerals and aqueous and gaseous species upon fluid-rock interaction and boiling. The sources of SO4 are taken to be multiple, including oxidation of S- II originating from basalt, leaching of SVI from the basalts and the seawater itself in the case of saline systems. In low-temperature fluids, the δ34S and Δ33S values reflect the various sources of sulfur. For high-temperature fluids, fluid-rock interaction, ∑ S- II oxidation and SO4 reduction and sulfide

Rolling-element fatigue life with traction fluids and automatic transmission fluid in a high-speed rolling-contact rig

NASA Technical Reports Server (NTRS)

Parker, R. J.; Nahm, A. H.; Loewenthal, S. H.

1982-01-01

Rolling-element fatigue tests were run in standard and high-speed rolling-contact rigs at bar speeds from 5000 to 50,000 rpm to determine the effects of speed and lubricant film parameter on rolling-element fatigue life. AISI 52100 test bars were tested at a maximum Hertz stress of 4.83 GPa (700,000 psi) with three traction fluids and an automatic transmission fluid. Rolling-element fatigue life increased with speed, with the greatest increases occurring from 10,000 to 50,000 rpm. The life data tended to follow published life-versus-lubricant-film-parameter data up to a film parameter of approximately 3.

A Reactive Transport Model for Marcellus Shale Weathering

NASA Astrophysics Data System (ADS)

Li, L.; Heidari, P.; Jin, L.; Williams, J.; Brantley, S.

2017-12-01

Shale formations account for 25% of the land surface globally. One of the most productive shale-gas formations is the Marcellus, a black shale that is rich in organic matter and pyrite. As a first step toward understanding how Marcellus shale interacts with water, we developed a reactive transport model to simulate shale weathering under ambient temperature and pressure conditions, constrained by soil chemistry and water data. The simulation was carried out for 10,000 years, assuming bedrock weathering and soil genesis began right after the last glacial maximum. Results indicate weathering was initiated by pyrite dissolution for the first 1,000 years, leading to low pH and enhanced dissolution of chlorite and precipitation of iron hydroxides. After pyrite depletion, chlorite dissolved slowly, primarily facilitated by the presence of CO2 and organic acids, forming vermiculite as a secondary mineral. A sensitivity analysis indicated that the most important controls on weathering include the presence of reactive gases (CO2 and O2), specific surface area, and flow velocity of infiltrating meteoric water. The soil chemistry and mineralogy data could not be reproduced without including the reactive gases. For example, pyrite remained in the soil even after 10,000 years if O2 was not continuously present in the soil column; likewise, chlorite remained abundant and porosity remained small with the presence of soil CO2. The field observations were only simulated successfully when the specific surface areas of the reactive minerals were 1-3 orders of magnitude smaller than surface area values measured for powdered minerals, reflecting the lack of accessibility of fluids to mineral surfaces and potential surface coating. An increase in the water infiltration rate enhanced weathering by removing dissolution products and maintaining far-from-equilibrium conditions. We conclude that availability of reactive surface area and transport of H2O and gases are the most important

Marital Conflict, Allostatic Load, and the Development of Children's Fluid Cognitive Performance

ERIC Educational Resources Information Center

Hinnant, J. Benjamin; El-Sheikh, Mona; Keiley, Margaret; Buckhalt, Joseph A.

2013-01-01

Relations between marital conflict, children's respiratory sinus arrhythmia (RSA), and fluid cognitive performance were examined over 3 years to assess allostatic processes. Participants were 251 children reporting on marital conflict, baseline RSA, and RSA reactivity (RSA-R) to a lab challenge were recorded, and fluid cognitive performance…

A New Method of Obtaining High-Resolution Paleoclimate Records from Speleothem Fluid Inclusions

NASA Astrophysics Data System (ADS)

Logan, A. J.; Horton, T. W.

2010-12-01

We present a new method for stable hydrogen and oxygen isotope analysis of ancient drip water trapped within cave speleothems. Our method improves on existing fluid inclusion isotopic analytical techniques in that it decreases the sample size by a factor of ten or more, dramatically improving the spatial and temporal precision of fluid inclusion-based paleoclimatology. Published thermal extraction methods require large samples (c. 150 mg) and temperatures high enough (c. 500-900°C) to cause calcite decomposition, which is also associated with isotopic fractionation of the trapped fluids. Extraction by crushing faces similar challenges, where the failure to extract all the trapped fluid can result in isotopic fractionation, and samples in excess of 500 mg are required. Our new method combines the strengths of these published thermal and crushing methods using continuous-flow isotope ratio analytical techniques. Our method combines relatively low-temperature (~250°C) thermal decrepitation with cryogenic trapping across a switching valve sample loop. In brief, ~20 mg carbonate samples are dried (75°C for >1 hour) and heated (250°C for >1 hour) in a quartz sample chamber under a continuously flowing stream of ultra-high purity helium. Heating of the sample chamber is achieved by use of a tube furnace. Fluids released during the heating step are trapped in a coiled stainless steel cold trap (~ -98°C) serving as the sample loop in a 6-way switching valve. Trapped fluids are subsequently injected into a high-temperature conversion elemental analyzer by switching the valve and rapidly thawing the trap. This approach yielded accurate and precise measurements of injected liquid water IAEA reference materials (GISP; SMOW2; SLAP2) for both hydrogen and oxygen isotopic compositions. Blanking tests performed on the extraction line demonstrate extremely low line-blank peak heights (<50mv). Our tests also demonstrate that complete recovery of liquid water is possible and that

Reactive Strength Index: A Poor Indicator of Reactive Strength?

PubMed

Healy, Robin; Kenny, Ian; Harrison, Drew

2017-11-28

The primary aim was to assess the relationships between reactive strength measures and associated kinematic and kinetic performance variables achieved during drop jumps. A secondary aim was to highlight issues with the use of reactive strength measures as performance indicators. Twenty eight national and international level sprinters, consisting of fourteen men and women, participated in this cross-sectional analysis. Athletes performed drop jumps from a 0.3 m box onto a force platform with dependent variables contact time (CT), landing time (TLand), push-off time (TPush), flight time (FT), jump height (JH), reactive strength index (RSI, calculated as JH / CT), reactive strength ratio (RSR, calculated as FT / CT) and vertical leg spring stiffness (Kvert) recorded. Pearson's correlation test found very high to near perfect relationships between RSI and RSR (r = 0.91 to 0.97), with mixed relationships found between RSI, RSR and the key performance variables, (Men: r = -0.86 to -0.71 between RSI/RSR and CT, r = 0.80 to 0.92 between RSI/RSR and JH; Women: r = -0.85 to -0.56 between RSR and CT, r = 0.71 between RSI and JH). This study demonstrates that the method of assessing reactive strength (RSI versus RSR) may be influenced by the performance strategies adopted i.e. whether an athlete achieves their best reactive strength scores via low CTs, high JHs or a combination. Coaches are advised to limit the variability in performance strategies by implementing upper and / or lower CT thresholds to accurately compare performances between individuals.

Focusing fluids towards the arc: the role of rheology and reactions

NASA Astrophysics Data System (ADS)

Wilson, C. R.; Spiegelman, M. W.

2014-12-01

Aqueous fluids released from the down-going slab in subduction zones are generally thought to be the cause of arc volcanism. However there is a significant discrepancy between the consistent location of the volcanic front with respect to intermediate depth earthquakes (e.g. 100+/-40 km; England et al., GJI, 2004, Syracuse & Abers, G-cubed, 2006) and the large depth range over which dehydration reactions are predicted to occur in the slab (e.g. 80-250 km; van Keken et al., JGR, 2011). By coupling the fluid flow to the solid rheology through compaction pressure, recent numerical models (Wilson et al., EPSL, 2014) demonstrated a number of focusing mechanisms that can be invoked to explain this apparent discrepancy. Most notable among these were permeability channels within the slab. These were shown to be highly effective in transporting fluid from deeper fluid sources along the slab towards the shallowest source. In the presence of these channels the majority of the fluid is released into the mantle wedge far shallower and closer to the arc than it was originally generated. While observations consistent with free fluids in the slab have been reported (e.g. Shiina et al., GRL, 2013), it is possible that changing the rheology and reactivity of the slab can change the efficiency of in-slab transport. We present a series of simplified model problems of fluid flow within the slab and mantle wedge demonstrating the potential effect of these processes on fluid flux. In particular, pseudo-1D models show that if fluids can efficiently rehydrate slab minerals, then these reactions can shut down fluid pathways within the slab, resulting in deeper release of fluid into the mantle wedge. However, the behavior in full subduction zone models remains to be determined.

Micro-topography and reactivity of implant surfaces: an in vitro study in simulated body fluid (SBF).

PubMed

Gandolfi, M G; Taddei, P; Siboni, F; Perrotti, V; Iezzi, G; Piattelli, A; Prati, C

2015-02-01

The creation of micro-textured dental implant surfaces possessing a stimulating activity represents a challenge in implant dentistry; particularly, the formation of a thin, biologically active, calcium-phosphate layer on their surface could help to strengthen the bond to the surrounding bone. The aim of the present study was to characterize in terms of macrostructure, micro-topography and reactivity in simulated body fluid (SBF), the surface of titanium (Ti) implants blasted with TiO2 particles, acid etched with hydrofluoric acid, and activated with Ca and Mg-containing nanoparticles. Sandblasted and acid-etched implants were analyzed by ESEM-EDX (environmental scanning electron microscope with energy dispersive X-ray system) to study the micromorphology of the surface and to perform elemental X-ray microanalysis (microchemical analyses) and element mapping. ESEM-EDX analyses were performed at time 0 and after a 28-day soaking period in SBF Hank's balanced salt solution (HBSS) following ISO 23317 (implants for surgery—in vitro evaluation for apatite-forming ability of implant materials). Microchemical analyses (weight % and atomic %) and element mapping were carried out to evaluate the relative element content, element distribution, and calcium/phosphorus (Ca/P) atomic ratio. Raman spectroscopy was used to assess the possible presence of impurities due to manufacturing and to investigate the phases formed upon HBSS soaking. Micro-morphological analyses showed a micro-textured, highly rough surface with microgrooves. Microchemical analyses showed compositional differences among the apical, middle, and distal thirds. The micro-Raman analyses of the as-received implant showed the presence of amorphous Ti oxide and traces of anatase, calcite, and a carbonaceous material derived from the decomposition of an organic component of lipidic nature (presumably used as lubricant). A uniform layer of Ca-poor calcium phosphates (CaPs) (Ca/P ratio <1.47) was observed after

Multicomponent Macrocyclization Reactions (MCMRs) Employing Highly Reactive Acyl Ketene and Nitrile Oxide Intermediates

PubMed Central

Knapp, John M.; Fettinger, James C.; Kurth, Mark J.

2011-01-01

An efficient synthesis of spiro-fused macrolactams by a multicomponent macrocyclization reaction (MCMR) is reported. The use of highly reactive, transient intermediates in this MCMR permits short reaction times, even at high dilution. The methods employed for this MCMR were first developed as a four component strategy for the synthesis of β-ketoamide isoxazolines. PMID:21827181

The antioxidant system of seminal fluid during in vitro storage of sterlet Acipenser ruthenus sperm.

PubMed

Dzyuba, Viktoriya; Cosson, Jacky; Dzyuba, Borys; Yamaner, Gunes; Rodina, Marek; Linhart, Otomar

2016-04-01

The role of the seminal fluid antioxidant system in protection against damage to spermatozoa during in vitro sperm storage is unclear. This study investigated the effect of in vitro storage of sterlet Acipenser ruthenus spermatozoa together with seminal fluid for 36 h at 4 °C on spermatozoon motility rate and curvilinear velocity, thiobarbituric acid reactive substance level, and components of enzyme and non-enzyme antioxidant system (superoxide dismutase and catalase activity and uric acid concentration) in seminal fluid. Spermatozoon motility parameters after sperm storage were significantly decreased, while the level of thiobarbituric acid reactive substances, activity of superoxide dismutase and catalase, and uric acid concentration did not change. Our findings suggest that the antioxidant system of sterlet seminal fluid is effective in preventing oxidative stress during short-term sperm storage and prompt future investigations of changes in spermatozoon homeostasis and in spermatozoon plasma membrane structure which are other possible reasons of spermatozoon motility deterioration upon sperm storage.

Highly reactive free radicals in electronic cigarette aerosols.

PubMed

Goel, Reema; Durand, Erwann; Trushin, Neil; Prokopczyk, Bogdan; Foulds, Jonathan; Elias, Ryan J; Richie, John P

2015-09-21

Electronic cigarette (EC) usage has increased exponentially, but limited data are available on its potential harmful effects. We tested for the presence of reactive, short-lived free radicals in EC aerosols by electron paramagnetic resonance spectroscopy (EPR) using the spin-trap phenyl-N-tert-butylnitrone (PBN). Radicals were detected in aerosols from all ECs and eliquids tested (2.5 × 10(13) to 10.3 × 10(13) radicals per puff at 3.3 V) and from eliquid solvents propylene glycol and glycerol and from "dry puffing". These results demonstrate, for the first time, the production of highly oxidizing free radicals from ECs which may present a potential toxicological risk to EC users.

Numerical simulation of miscible viscous fingering with viscosity change in a displacing fluid by chemical reaction

NASA Astrophysics Data System (ADS)

Omori, Keiichiro; Nagatsu, Yuichiro

2017-11-01

Viscous fingering (VF) with viscosity changes by chemical reactions in case of miscible systems have been investigated both experimentally and theoretically in the recent years. Nagatsu et al. investigated experimentally miscible VF in which viscosity of the displaced fluid or the displacing one is changed by fast chemical reaction They showed that VF was more dense by the viscosity increase whereas less dense by the viscosity increase regardless of whether the viscosity change occurs in the displaced fluid or displacing one. From a theoretical viewpoint, numerical simulation performed on the reactive VF where viscosity of the displaced fluid is changed by instantaneously fast chemical reaction. The results had a good agreement with those in the corresponding experiment. In this work, we have conducted numerical simulation on such reactive VF where viscosity of the displacing fluid is changed. We have found the results have a good agreement with the corresponding experimental ones.

VERifyNow in DIabetes high-on-treatment platelet reactivity: a pharmacodynamic study on switching from clopidogrel to prasugrel.

PubMed

Cubero Gómez, José M; Acosta Martínez, Juan; Mendias Benítez, Crsitina; Díaz De La Llera, Luis S; Fernández-Quero, Mónica; Guisado Rasco, Agustí; Villa Gil-Ortega, Manuel; Sánchez González, Ángel

2015-12-01

Diabetic patients with an acute coronary syndrome undergoing percutaneous coronary intervention frequently exhibit high platelet reactivity while on clopidogrel. We hypothesized that in diabetic patients undergoing percutaneous coronary intervention, who exhibit high-platelet-reactivity after standard treatment with clopidogrel, a 60-mg prasugrel loading dose is superior to standard treatment with clopidogrel for optimal P2Y12 inhibition within the first 24-36 h post-angioplasty. VERDI was a prospective, randomized, single-centre, single-blind, parallel-design study (NCT01684813). Consecutive diabetic patients with an non-ST-segment elevation acute coronary syndrome undergoing percutaneous coronary intervention and loaded with clopidogrel were considered for platelet reactivity assessment immediately before angioplasty with the VerifyNow assay measured in P2Y12 reaction units (PRU). Fifty of 63 screened patients (79.4%) had high platelet reactivity (PRU ≥ 208) and were randomized to receive a 60-mg prasugrel loading dose (n = 25) versus clopidogrel standard dose (n = 25). Platelet function was assessed again 24 hours post-angioplasty. Prasugrel achieved greater platelet inhibition than clopidogrel 24 hours post-angioplasty (median [interquartile range], 38 [9-72] vs 285 [240-337], respectively; P < 0.001). The non-high-platelet-reactivity rate (PRU < 208) at 24 h post-angioplasty (primary end point) was higher with prasugrel; 25 patients (100%) in the prasugrel group achieved optimal antiaggregation vs 4 patients (16%) in the clopidogrel group (P < 0.001). No significant acute bleeding was documented in either group. Among type 2 diabetic patients suffering an acute coronary syndrome with high-platelet-reactivity undergoing percutaneous coronary intervention, switching from clopidogrel to prasugrel was superior to standard treatment with clopidogrel for the achievement of optimal antiaggregation within the first 24 hours post-angioplasty.

Correlation Between High-sensitivity C-reactive Protein and Reactive Oxygen Metabolites During A One-year Period Among Asymptomatic Subjects

PubMed Central

Kotani, Kazuhiko; Taniguchi, Nobuyuki

2012-01-01

Background Inflammation and oxidative stress are associated with human health and the disease status. The present study aimed to investigate the longitudinal correlation between the diacron reactive oxygen metabolites (d-ROMs) level, as an oxidative stress-related marker, and high-sensitivity C-reactive protein (hsCRP), as an inflammatory marker, during a one-year period among asymptomatic subjects. Methods The data, including anthropometric and biochemical markers, were collected at baseline and after the one-year period from 71 participants (male/female = 41/30, mean age 50 years). The correlation between the changes of the d-ROMs and hsCRP levels during the study period was examined. Results A simple correlation analysis showed a significant and positive correlation to exist between the changes of the d-ROMs and hsCRP levels (r = 0.40, P < 0.01). This significant correlation remained independent in a multiple linear regression analysis adjusted for confounding factors. Conclusions The present findings suggest that the relationship between the d-ROMs and hsCRP levels could be prospectively followed, and that monitoring both markers may help to better understand the cooperation of inflammation and oxidative stress in association with health and disease. Further studies are necessary to clarify the biological mechanism(s) responsible for the observed relationship. Keywords Oxidative stress; Oxygen reactive species; Inflammation; CRP PMID:22383928

Sources and drains: Major controls of hydrothermal fluid flow in the Kokanee Range, British Columbia, Canada

NASA Astrophysics Data System (ADS)

Beaudoin, Georges; Therrien, René

1999-10-01

Vein fields are fractured domains of the lithosphere that have been infiltrated by hydrothermal fluids, which deposited minerals in response to changing physico-chemical conditions. Because oxygen is a major component of the infiltrating fluid and the surrounding rock matrix, the oxygen isotope composition of minerals found in veins is used to decipher ancient fluid flow within the lithosphere. We use a numerical model to simulate oxygen isotope transport in the Kokanee Range silver-lead-zinc vein field. The model considers advective, dispersive, and reactive transport in a three-dimensional porous rock matrix intersected by high-permeability planes representing fracture zones. Here we show that it is the geometrical configuration of the sources and of the drains of hydrothermal fluids, combined with the fracture pattern, that exerts the main control on the oxygen isotope distribution. Other factors that affect, to a lesser extent, the values and positions of oxygen isopleths are the fluids and rock-matrix isotopic compositions, the isotopic fractionation, the reaction rate constant, and hydraulic conductivities of the rock matrix and fracture zones.

Comparison of high-sensitivity C-reactive protein and fetuin-A levels before and after treatment for subjects with subclinical hyperthyroidism.

PubMed

Bilgir, Oktay; Bilgir, Ferda; Topcuoglu, Tuba; Calan, Mehmet; Calan, Ozlem

2014-03-01

This study was designed to show the effect of propylthiouracil treatment on sCD40L, high-sensitivity C-reactive protein, and fetuin-A levels on subjects with subclinical hyperthyroidism. After checking sCD40L, high-sensitivity C-reactive protein, and fetuin-A levels of 35 patients with subclinical hyperthyroidism, each was given 50 mg tablets of propylthiouracil three times daily. After 3 months, sCD40L, high-sensitivity C-reactive protein, and fetuin-A levels were then compared to the levels before treatment. Although high-sensitivity C-reactive protein and sCD40L levels were normal in the subclinical hyperthyroidism patients compared to the healthy controls, fetuin-A levels were statistically significantly higher (*p = 0.022). After treatment, fetuin-A levels of subclinical hyperthyroidism patients decreased statistically significantly compared to the levels before treatment (**p = 0.026). sCD40L and high-sensitivity C-reactive protein levels did not have a statistically significant difference compared to the control group and post-propylthiouracil treatment. In subclinical hyperthyroidism patients, high fetuin-A levels before propylthiouracil treatment and decreases in these levels after treatment in cases with subclinical hyperthyroidism indicated the possibility of preventing long-term cardiac complications with propylthiouracil treatment.

Reactive navigation in extremely dense and highly intricate environments

PubMed Central

2017-01-01

Reactive navigation is a well-known paradigm for controlling an autonomous mobile robot, which suggests making all control decisions through some light processing of the current/recent sensor data. Among the many advantages of this paradigm are: 1) the possibility to apply it to robots with limited and low-priced hardware resources, and 2) the fact of being able to safely navigate a robot in completely unknown environments containing unpredictable moving obstacles. As a major disadvantage, nevertheless, the reactive paradigm may occasionally cause robots to get trapped in certain areas of the environment—typically, these conflicting areas have a large concave shape and/or are full of closely-spaced obstacles. In this last respect, an enormous effort has been devoted to overcome such a serious drawback during the last two decades. As a result of this effort, a substantial number of new approaches for reactive navigation have been put forward. Some of these approaches have clearly improved the way how a reactively-controlled robot can move among densely cluttered obstacles; some other approaches have essentially focused on increasing the variety of obstacle shapes and sizes that could be successfully circumnavigated; etc. In this paper, as a starting point, we choose the best existing reactive approach to move in densely cluttered environments, and we also choose the existing reactive approach with the greatest ability to circumvent large intricate-shaped obstacles. Then, we combine these two approaches in a way that makes the most of them. From the experimental point of view, we use both simulated and real scenarios of challenging complexity for testing purposes. In such scenarios, we demonstrate that the combined approach herein proposed clearly outperforms the two individual approaches on which it is built. PMID:29287078

Reactive high power impulse magnetron sputtering

NASA Astrophysics Data System (ADS)

Gudmundsson, J. T.; Magnus, F.; Tryggvason, T. K.; Sveinsson, O. B.; Olafsson, S.

2012-10-01

Here we discuss reactive high power impulse magnetron sputtering sputtering (HiPIMS) [1] of Ti target in an Ar/N2 and Ar/O2 atmosphere. The discharge current waveform is highly dependent on both the pulse repetition frequency and discharge voltage. The discharge current increases with decreasing frequency or voltage. This we attribute to an increase in the secondary electron emission yield during the self-sputtering phase of the pulse, as nitride [2] or oxide [3] forms on the target. We also discuss the growth of TiN films on SiO2 at temperatures of 22-600 ^oC. The HiPIMS process produces denser films at lower growth temperature and the surface is much smoother and have a significantly lower resistivity than dc magnetron sputtered films on SiO2 at all growth temperatures due to reduced grain boundary scattering [4].[4pt] [1] J. T. Gudmundsson, N. Brenning, D. Lundin and U. Helmersson, J. Vac. Sci. Technol. A, 30 030801 (2012)[0pt] [2] F. Magnus, O. B. Sveinsson, S. Olafsson and J. T. Gudmundsson, J. Appl. Phys., 110 083306 (2011)[0pt] [3] F. Magnus, T. K. Tryggvason, S. Olafsson and J. T. Gudmundsson, J. Vac. Sci. Technol., submitted 2012[0pt] [4] F. Magnus, A. S. Ingason, S. Olafsson and J. T. Gudmundsson, IEEE Elec. Dev. Lett., accepted 2012

High precision Hugoniot measurements on statically pre-compressed fluid helium

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

Seagle, Christopher T.; Reinhart, William D.; Lopez, Andrew J.

Here we describe how the capability for statically pre-compressing fluid targets for Hugoniot measurements utilizing gas gun driven flyer plates has been developed. Pre-compression expands the capability for initial condition control, allowing access to thermodynamic states off the principal Hugoniot. Absolute Hugoniot measurements with an uncertainty less than 3% on density and pressure were obtained on statically pre-compressed fluid helium utilizing a two stage light gas gun. Helium is highly compressible; the locus of shock states resulting from dynamic loading of an initially compressed sample at room temperature is significantly denser than the cryogenic fluid Hugoniot even for relatively modestmore » (0.27–0.38 GPa) initial pressures. Lastly, the dynamic response of pre-compressed helium in the initial density range of 0.21–0.25 g/cm3 at ambient temperature may be described by a linear shock velocity (us) and particle velocity (u p) relationship: u s = C 0 + su p, with C 0 = 1.44 ± 0.14 km/s and s = 1.344 ± 0.025.« less

Teaching fluid mechanics to high schoolers: methods, challenges, and outcome

NASA Astrophysics Data System (ADS)

Manikantan, Harishankar

2017-11-01

This talk will summarize the goals, methods, and both short- and long-term feedback from two high-school-level courses in fluid mechanics involving 43 students and cumulatively spanning over 100 hours of instruction. The goals of these courses were twofold: (a) to spark an interest in science and engineering and attract a more diverse demographic into college-level STEM programs; and (b) to train students in a `college-like' method of approaching the physics of common phenomena, with fluid mechanics as the context. The methods of instruction included classes revolving around the idea of dispelling misconceptions, group activities, `challenge' rounds and mock design projects to use fluid mechanics phenomena to achieve a specified goal, and simple hands-on experiments. The feedback during instruction was overwhelmingly positive, particularly in terms of a changing and favorable attitude towards math and engineering. Long after the program, a visible impact lies in a diverse group of students acknowledging that the course had a positive effect in their decision to choose an engineering or science major in a four-year college.

High precision Hugoniot measurements on statically pre-compressed fluid helium

DOE PAGES

Seagle, Christopher T.; Reinhart, William D.; Lopez, Andrew J.; ...

2016-09-27

Here we describe how the capability for statically pre-compressing fluid targets for Hugoniot measurements utilizing gas gun driven flyer plates has been developed. Pre-compression expands the capability for initial condition control, allowing access to thermodynamic states off the principal Hugoniot. Absolute Hugoniot measurements with an uncertainty less than 3% on density and pressure were obtained on statically pre-compressed fluid helium utilizing a two stage light gas gun. Helium is highly compressible; the locus of shock states resulting from dynamic loading of an initially compressed sample at room temperature is significantly denser than the cryogenic fluid Hugoniot even for relatively modestmore » (0.27–0.38 GPa) initial pressures. Lastly, the dynamic response of pre-compressed helium in the initial density range of 0.21–0.25 g/cm3 at ambient temperature may be described by a linear shock velocity (us) and particle velocity (u p) relationship: u s = C 0 + su p, with C 0 = 1.44 ± 0.14 km/s and s = 1.344 ± 0.025.« less

High-Frequency Heart Rate Variability Reactivity and Trait Worry Interact to Predict the Development of Sleep Disturbances in Response to a Naturalistic Stressor.

PubMed

MacNeil, Sasha; Deschênes, Sonya S; Caldwell, Warren; Brouillard, Melanie; Dang-Vu, Thien-Thanh; Gouin, Jean-Philippe

2017-12-01

High-frequency heart rate variability (HF-HRV) reactivity was proposed as a vulnerability factor for stress-induced sleep disturbances. Its effect may be amplified among individuals with high trait worry or sleep reactivity. This study evaluated whether HF-HRV reactivity to a worry induction, sleep reactivity, and trait worry predict increases in sleep disturbances in response to academic stress, a naturalistic stressor. A longitudinal study following 102 undergraduate students during an academic semester with well-defined periods of lower and higher academic stress was conducted. HF-HRV reactivity to a worry induction, trait worry using the Penn State Worry Questionnaire, and sleep reactivity using the Ford Insomnia Stress Reactivity Test were measured during the low stress period. Sleep disturbances using the Pittsburgh Sleep Quality Index were assessed twice during the lower stress period and three times during the higher stress period. Greater reductions in HF-HRV in response to the worry induction predicted increases in sleep disturbances from the lower to the higher academic stress period. Trait worry moderated this association: individuals with both higher trait worry and greater HF-HRV reactivity to worry had larger increases in stress-related sleep disturbances over time, compared to participants with lower trait worry and HF-HRV reactivity. A similar, but marginally significant effect was found for sleep reactivity. This study supports the role of HF-HRV reactivity as a vulnerability factor for stress-induced sleep disturbances. The combination of high trait worry and high HF-HRV reactivity to worry might identify a subgroup of individuals most vulnerable to stress-related sleep disturbances.

High-resolution simulations of multi-phase flow in magmatic-hydrothermal systems with realistic fluid properties

NASA Astrophysics Data System (ADS)

Geiger, S.; Driesner, T.; Matthai, S.; Heinrich, C.

2002-12-01

Realistic modelling of multi-phase fluid flow, energy and component transport in magmatic-hydrothermal systems is very challenging because hydrological properties of fluids and rocks vary over many orders of magnitude and the geometric complexities of such systems. Furthermore, density dependent component transport and transient permeability variations due to P-T changes and fluid-rock interactions introduce additional difficulties. As a result, the governing equations for the hydrodynamics, energy and component transport, and thermodynamics in magmatic hydrothermal systems are highly non-linear and strongly coupled. Essential requirements of a numerical formulation for such a system are: (1) a treatment of the hydrodynamics that can accurately resolve complex geological structures and represent the highly variable fluid velocities herein, (2) a realistic thermodynamic representation of the fluid properties including the wide P-T-X range of liquid+vapour coexistence for the highly saline fluids, and (3) an accurate handling of the highly contrasting transport properties of the two fluids. We are combining higher order finite-element (FE) methods with total variation diminishing finite volume (TVDFV) methods to model the hydrodynamics and energy and component transport of magmatic hydrothermal systems. Combined FE and TVDFV methods are mass and shock preserving, yield great geometric flexibility in 2D and 3D [2]. Furthermore, efficient matrix solvers can be employed to model fluid flow in geologically realistic structures [5]. The governing equations are linearized by operator-splitting and solved sequentially using a Picard iteration scheme. We chose the system water-NaCl as a realistic proxy for natural fluids occurring in magmatic-hydrothermal systems. An in-depth evaluation of the available experimental and theoretical data led to a consistent and accurate set of formulations for the PVTXH relations that are valid from 0 to 800 C, 0 to 500 MPa, and 0 to 1 XNa

Impact of microstructure evolution on the difference between geometric and reactive surface areas in natural chalk

NASA Astrophysics Data System (ADS)

Yang, Y.; Bruns, S.; Stipp, S. L. S.; Sørensen, H. O.

2018-05-01

The coupling between flow and mineral dissolution drives the evolution of many natural and engineered flow systems. Pore surface changes as microstructure evolves but this transient behaviour has traditionally been difficult to model. We combined a reactor network model with experimental, greyscale tomography data to establish the morphological grounds for differences among geometric, reactive and apparent surface areas in dissolving chalk. This approach allowed us to study the effects of initial geometry and macroscopic flow rate independently. The simulations showed that geometric surface, which represents a form of local transport heterogeneity, increases in an imposed flow field, even when the porous structure is chemically homogeneous. Hence, the fluid-reaction coupling leads to solid channelisation, which further results in fluid focusing and an increase in geometric surface area. Fluid focusing decreases the area of reactive surface and the residence time of reactant, both contribute to the over-normalisation of reaction rate. In addition, the growing and merging of microchannels, near the fluid entrance, contribute to the macroscopic, fast initial dissolution rate of rocks.

High precision during food recruitment of experienced (reactivated) foragers in the stingless bee Scaptotrigona mexicana (Apidae, Meliponini)

NASA Astrophysics Data System (ADS)

Sánchez, Daniel; Nieh, James C.; Hénaut, Yann; Cruz, Leopoldo; Vandame, Rémy

Several studies have examined the existence of recruitment communication mechanisms in stingless bees. However, the spatial accuracy of location-specific recruitment has not been examined. Moreover, the location-specific recruitment of reactivated foragers, i.e., foragers that have previously experienced the same food source at a different location and time, has not been explicitly examined. However, such foragers may also play a significant role in colony foraging, particularly in small colonies. Here we report that reactivated Scaptotrigona mexicana foragers can recruit with high precision to a specific food location. The recruitment precision of reactivated foragers was evaluated by placing control feeders to the left and the right of the training feeder (direction-precision tests) and between the nest and the training feeder and beyond it (distance-precision tests). Reactivated foragers arrived at the correct location with high precision: 98.44% arrived at the training feeder in the direction trials (five-feeder fan-shaped array, accuracy of at least +/-6° of azimuth at 50 m from the nest), and 88.62% arrived at the training feeder in the distance trials (five-feeder linear array, accuracy of at least +/-5 m or +/-10% at 50 m from the nest). Thus, S. mexicana reactivated foragers can find the indicated food source at a specific distance and direction with high precision, higher than that shown by honeybees, Apis mellifera, which do not communicate food location at such close distances to the nest.

Hydroetching of high surface area ceramics using moist supercritical fluids

DOEpatents

Fryxell, Glen; Zemanian, Thomas S.

2004-11-02

Aerogels having a high density of hydroxyl groups and a more uniform pore size with fewer bottlenecks are described. The aerogel is exposed to a mixture of a supercritical fluid and water, whereupon the aerogel forms a high density of hydroxyl groups. The process also relaxes the aerogel into a more open uniform internal structure, in a process referred to as hydroetching. The hydroetching process removes bottlenecks from the aerogels, and forms the hydrogels into more standard pore sizes while preserving their high surface area.

Distinguishing infected from noninfected abdominal fluid collections after surgery: an imaging, clinical, and laboratory-based scoring system.

PubMed

Gnannt, Ralph; Fischer, Michael A; Baechler, Thomas; Clavien, Pierre-Alain; Karlo, Christoph; Seifert, Burkhardt; Lesurtel, Mickael; Alkadhi, Hatem

2015-01-01

Mortality from abdominal abscesses ranges from 30% in treated cases up to 80% to 100% in patients with undrained or nonoperated abscesses. Various computed tomographic (CT) imaging features have been suggested to indicate infection of postoperative abdominal fluid collections; however, features are nonspecific and substantial overlap between infected and noninfected collections exists. The purpose of this study was to develop and validate a scoring system on the basis of CT imaging findings as well as laboratory and clinical parameters for distinguishing infected from noninfected abdominal fluid collections after surgery. The score developmental cohort included 100 consecutive patients (69 men, 31 women; mean age, 58 ± 17 years) who underwent portal-venous phase CT within 24 hours before CT-guided intervention of postoperative abdominal fluid collections. Imaging features included attenuation (Hounsfield unit [HU]), volume, wall enhancement and thickness, fat stranding, as well as entrapped gas of fluid collections. Laboratory and clinical parameters included diabetes, intake of immunosuppressive drugs, body temperature, C-reactive protein, and leukocyte blood cell count. The score was validated in a separate cohort of 30 consecutive patients (17 men, 13 women; mean age, 51 ± 15 years) with postoperative abdominal fluid collections. Microbiologic analysis from fluid samples served as the standard of reference. Diabetes, body temperature, C-reactive protein, attenuation of the fluid collection (in HUs), wall enhancement and thickness of the wall, adjacent fat stranding, as well as entrapped gas within the fluid collection were significantly different between infected and noninfected collections (P < 0.001). Multiple logistic regression analysis revealed diabetes, C-reactive protein, attenuation of the fluid collection (in HUs), as well as entrapped gas as significant independent predictors of infection (P < 0.001) and thus was selected for constructing a scoring

Critical cerebral perfusion pressure at high intracranial pressure measured by induced cerebrovascular and intracranial pressure reactivity.

PubMed

Bragin, Denis E; Statom, Gloria L; Yonas, Howard; Dai, Xingping; Nemoto, Edwin M

2014-12-01

The lower limit of cerebral blood flow autoregulation is the critical cerebral perfusion pressure at which cerebral blood flow begins to fall. It is important that cerebral perfusion pressure be maintained above this level to ensure adequate cerebral blood flow, especially in patients with high intracranial pressure. However, the critical cerebral perfusion pressure of 50 mm Hg, obtained by decreasing mean arterial pressure, differs from the value of 30 mm Hg, obtained by increasing intracranial pressure, which we previously showed was due to microvascular shunt flow maintenance of a falsely high cerebral blood flow. The present study shows that the critical cerebral perfusion pressure, measured by increasing intracranial pressure to decrease cerebral perfusion pressure, is inaccurate but accurately determined by dopamine-induced dynamic intracranial pressure reactivity and cerebrovascular reactivity. Cerebral perfusion pressure was decreased either by increasing intracranial pressure or decreasing mean arterial pressure and the critical cerebral perfusion pressure by both methods compared. Cortical Doppler flux, intracranial pressure, and mean arterial pressure were monitored throughout the study. At each cerebral perfusion pressure, we measured microvascular RBC flow velocity, blood-brain barrier integrity (transcapillary dye extravasation), and tissue oxygenation (reduced nicotinamide adenine dinucleotide) in the cerebral cortex of rats using in vivo two-photon laser scanning microscopy. University laboratory. Male Sprague-Dawley rats. At each cerebral perfusion pressure, dopamine-induced arterial pressure transients (~10 mm Hg, ~45 s duration) were used to measure induced intracranial pressure reactivity (Δ intracranial pressure/Δ mean arterial pressure) and induced cerebrovascular reactivity (Δ cerebral blood flow/Δ mean arterial pressure). At a normal cerebral perfusion pressure of 70 mm Hg, 10 mm Hg mean arterial pressure pulses had no effect on

Methanethiol abundance in high-temperature hydrothermal fluids from the Mid-Atlantic Ridge

NASA Astrophysics Data System (ADS)

Reeves, E.; Seewald, J. S.; Saccocia, P.; van der Meer, M.

2008-12-01

metabolism in highly-reducing alkaline hydrothermal environments invoke CH3SH as a key reactant leading to Acetyl CoA-based (Wood-Ljungdahl) carbon fixation pathways. Results of this study challenge the notion that high-pH, reducing fluids emanating from serpentinite-hosted hydrothermal systems like Lost City were favorable for the production of CH3SH, the establishment of a primitive metabolic cycle and the emergence of microbial life on Earth.

Tectonic inheritance, reactivation and long term fault weakening processes

NASA Astrophysics Data System (ADS)

Holdsworth, Bob

2017-04-01

This talk gives a geological review of weakening processes in faults and their long-term effect on reactivation and tectonic inheritance during crustal deformation. Examples will be drawn from the Atlantic margins, N America, Japan and the Alps. Tectonic inheritance and reactivation are fundamentally controlled by the processes of stress concentration and shear localisation manifested at all scales in the continental lithosphere. Lithosphere-scale controls include crustal thickness, thermal age and the boundary conditions imposed by the causative plate tectonic processes during extension. At the other end of the scale range, grain-scale controls include local environmental controls (depth, stress, strain rate), rock composition, grainsize, fabric intensity and the presence of fluids or melt. Intermediate-scale geometric controls are largely related to the size, orientation and interconnectivity of pre-existing anisotropies. If reactivation of pre-existing structures occurs, it likely requires a combination of processes across all three scale ranges to be favourable. This can make the unequivocal recognition of inheritance and reactivation difficult. Large (e.g. crustal-scale) pre-existing structures are especially important due to their ability to efficiently concentrate stress and localise strain. For big faults (San Andreas, Great Glen, Median Tectonic Line), detailed studies of the associated exposed fault rocks indicate that reactivation is linked to the development of strongly anisotropic phyllosilicate-rich fault rocks that are weak (e.g. friction coefficients as low as 0.2 or less) under a broad range of deformation conditions. In the case of pre-existing regional dyke swarms (S Atlantic, NW Scotland) - which may themselves track deep mantle fabrics at depth - multiple reactivation of dyke margins is widespread and may preclude reactivation of favourably oriented local basement fabrics. In a majority of cases, pre-existing structures in the crust are

High Throughput ELISAs to Measure a Unique Glycan on Transferrin in Cerebrospinal Fluid: A Possible Extension toward Alzheimer's Disease Biomarker Development.

PubMed

Shirotani, Keiro; Futakawa, Satoshi; Nara, Kiyomitsu; Hoshi, Kyoka; Saito, Toshie; Tohyama, Yuriko; Kitazume, Shinobu; Yuasa, Tatsuhiko; Miyajima, Masakazu; Arai, Hajime; Kuno, Atsushi; Narimatsu, Hisashi; Hashimoto, Yasuhiro

2011-01-01

We have established high-throughput lectin-antibody ELISAs to measure different glycans on transferrin (Tf) in cerebrospinal fluid (CSF) using lectins and an anti-transferrin antibody (TfAb). Lectin blot and precipitation analysis of CSF revealed that PVL (Psathyrella velutina lectin) bound an unique N-acetylglucosamine-terminated N-glycans on "CSF-type" Tf whereas SSA (Sambucus sieboldiana agglutinin) bound α2,6-N-acetylneuraminic acid-terminated N-glycans on "serum-type" Tf. PVL-TfAb ELISA of 0.5 μL CSF samples detected "CSF-type" Tf but not "serum-type" Tf whereas SSA-TfAb ELISA detected "serum-type" Tf but not "CSF-type" Tf, demonstrating the specificity of the lectin-TfAb ELISAs. In idiopathic normal pressure hydrocephalus (iNPH), a senile dementia associated with ventriculomegaly, amounts of the SSA-reactive Tf were significantly higher than in non-iNPH patients, indicating that Tf glycan analysis by the high-throughput lectin-TfAb ELISAs could become practical diagnostic tools for iNPH. The lectin-antibody ELISAs of CSF proteins might be useful for diagnosis of the other neurological diseases.

LONG-TERM PERFORMANCE ASSESSMENT OF PERMEABLE REACTIVE BARRIERS TO REMEDIATE CONTAMINATED GROUND WATER

EPA Science Inventory

Permeable reactive barriers (PRBs) are an emerging, alternative in-situ approach for remediating groundwater contamination that combine subsurface fluid flow management with a passive chemical treatment zone. The few pilot and commercial installations which have been implemented ...

On the Theory of Reactive Mixtures for Modeling Biological Growth

PubMed Central

Ateshian, Gerard A.

2013-01-01

Mixture theory, which can combine continuum theories for the motion and deformation of solids and fluids with general principles of chemistry, is well suited for modeling the complex responses of biological tissues, including tissue growth and remodeling, tissue engineering, mechanobiology of cells and a variety of other active processes. A comprehensive presentation of the equations of reactive mixtures of charged solid and fluid constituents is lacking in the biomechanics literature. This study provides the conservation laws and entropy inequality, as well as interface jump conditions, for reactive mixtures consisting of a constrained solid mixture and multiple fluid constituents. The constituents are intrinsically incompressible and may carry an electrical charge. The interface jump condition on the mass flux of individual constituents is shown to define a surface growth equation, which predicts deposition or removal of material points from the solid matrix, complementing the description of volume growth described by the conservation of mass. A formu-lation is proposed for the reference configuration of a body whose material point set varies with time. State variables are defined which can account for solid matrix volume growth and remodeling. Constitutive constraints are provided on the stresses and momentum supplies of the various constituents, as well as the interface jump conditions for the electrochem cal potential of the fluids. Simplifications appropriate for biological tissues are also proposed, which help reduce the governing equations into a more practical format. It is shown that explicit mechanisms of growth-induced residual stresses can be predicted in this framework. PMID:17206407

A new model of reaction-driven cracking: fluid volume consumption and tensile failure during serpentinization

NASA Astrophysics Data System (ADS)

Eichenbaum-Pikser, J. M.; Spiegelman, M. W.; Kelemen, P. B.; Wilson, C. R.

2013-12-01

Reactive fluid flow plays an important role in a wide range of geodynamic processes, such as melt migration, formation of hydrous minerals on fault surfaces, and chemical weathering. These processes are governed by the complex coupling between fluid transport, reaction, and solid deformation. Reaction-driven cracking is a potentially critical feedback mechanism, by which volume change associated with chemical reaction drives fracture in the surrounding rock. It has been proposed to play a role in both serpentinization and carbonation of peridotite, motivating consideration of its application to mineral carbon sequestration. Previous studies of reactive cracking have focused on the increase in solid volume, and as such, have considered failure in compression. However, if the consumption of fluid is considered in the overall volume budget, the reaction can be net volume reducing, potentially leading to failure in tension. To explore these problems, we have formulated and solved a 2-D model of coupled porous flow, reaction kinetics, and elastic deformation using the finite element model assembler TerraFERMA (Wilson et al, G3 2013 submitted). The model is applied to the serpentinization of peridotite, which can be reasonably approximated as the transfer of a single reactive component (H2O) between fluid and solid phases, making it a simple test case to explore the process. The behavior of the system is controlled by the competition between the rate of volume consumption by the reaction, and the rate of volume replacement by fluid transport, as characterized by a nondimensional parameter χ, which depends on permeability, reaction rate, and the bulk modulus of the solid. Large values of χ correspond to fast fluid transport relative to reaction rate, resulting in a low stress, volume replacing regime. At smaller values of χ, fluid transport cannot keep up with the reaction, resulting in pore fluid under-pressure and tensile solid stresses. For the range of χ relevant

Comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones.

PubMed

Carnes, Stephanie; O'Brien, Stacey; Szewczak, Angelica; Tremeau-Cayel, Lauriane; Rowe, Walter F; McCord, Bruce; Lurie, Ira S

2017-09-01

A comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones has been conducted. Nine different mixtures of bath salts were analyzed in this study. The three different chromatographic techniques were examined using a general set of controlled synthetic cathinones as well as a variety of other synthetic cathinones that exist as positional isomers. Overall 35 different synthetic cathinones were analyzed. A variety of column types and chromatographic modes were examined for developing each separation. For the ultra high performance supercritical fluid chromatography separations, analyses were performed using a series of Torus and Trefoil columns with either ammonium formate or ammonium hydroxide as additives, and methanol, ethanol or isopropanol organic solvents as modifiers. Ultra high performance liquid chromatographic separations were performed in both reversed phase and hydrophilic interaction chromatographic modes using SPP C18 and SPP HILIC columns. Gas chromatography separations were performed using an Elite-5MS capillary column. The orthogonality of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography was examined using principal component analysis. For the best overall separation of synthetic cathinones, the use of ultra high performance supercritical fluid chromatography in combination with gas chromatography is recommended. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the Versatility of Rheoreversible, Stimuli-responsive Hydraulic-Fracturing Fluids for Enhanced Geothermal Systems: Effect of Reservoir pH

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

Fernandez, Carlos A.; Shao, Hongbo; Bonneville, Alain

Abstract The primary challenge for the feasibility of enhanced geothermal systems (EGS) is to cost-effectively create high-permeability reservoirs inside deep crystalline bedrock. Although fracturing fluids are commonly used for oil/gas, standard fracturing methods are not developed or proven for EGS temperatures and pressures. Furthermore, the environmental impacts of currently used fracturing methods are only recently being determined. These authors recently reported an environmentally benign, CO2-activated, rheoreversible fracturing fluid that enhances permeability through fracturing due to in situ volume expansion and gel formation. The potential of this novel fracturing fluid is evaluated in this work towards its application at geothermal sitesmore » under different pH conditions. Laboratory-scale fracturing experiments using Coso Geothermal rock cores under different pH environments were performed followed by X-ray microtomography characterization. The results demonstrate that CO2-reactive aqueous solutions of environmentally amenable polyallylamine (PAA) consistently and reproducibly creates/propagates fracture networks through highly impermeable crystalline rock from Coso EGS sites at considerably lower effective stress as compared to conventional fracturing fluids. In addition, permeability was significantly enhanced in a wide range of formation-water pH values. This effective, and environmentally-friendly fracturing fluid technology represents a potential alternative to conventional fracturing fluids.« less

Characterization of commercial magnetorheological fluids at high shear rate: influence of the gap

NASA Astrophysics Data System (ADS)

Golinelli, Nicola; Spaggiari, Andrea

2018-07-01

This paper reports the experimental tests on the behaviour of a commercial MR fluid at high shear rates and the effect of the gap. Three gaps were considered at multiple magnetic fields and shear rates. From an extended set of almost two hundred experimental flow curves, a set of parameters for the apparent viscosity are retrieved by using the Ostwald de Waele model for non-Newtonian fluids. It is possible to simplify the parameter correlation by making the following considerations: the consistency of the model depends only on the magnetic field, the flow index depends on the fluid type and the gap shows an important effect only at null or very low magnetic fields. This lead to a simple and useful model, especially in the design phase of a MR based product. During the off state, with no applied field, it is possible to use a standard viscous model. During the active state, with high magnetic field, a strong non-Newtonian nature becomes prevalent over the viscous one even at very high shear rate; the magnetic field dominates the apparent viscosity change, while the gap does not play any relevant role on the system behaviour. This simple assumption allows the designer to dimension the gap only considering the non-active state, as in standard viscous systems, and taking into account only the magnetic effect in the active state, where the gap does not change the proposed fluid model.

Mineralogical changes of a well cement in various H2S-CO2(-brine) fluids at high pressure and temperature.

PubMed

Jacquemet, Nicolas; Pironon, Jacques; Saint-Marc, Jérémie

2008-01-01

The reactivity of a crushed well cement in contact with (1) a brine with dissolved H2S-CO2; (2) a dry H2S-CO2 supercritical phase; (3) a two-phase fluid associating a brine with dissolved H2S-CO2 and a H2S-CO2 supercritical phase was investigated in batch experiments at 500 bar and 120, 200 degrees C. All of the experiments showed that following 15-60 days cement carbonation occurred. The H2S reactivity with cement is limited since it only transformed the ferrites (minor phases) by sulfidation. It appeared that the primary parameter controlling the degree of carbonation (i.e., the rate of calcium carbonates precipitation and CSH (Calcium Silicate Hydrates) decalcification) is the physical state of the fluid phase contacting the minerals. The carbonation degree is complete when the minerals contact at least the dry H2S-CO2 supercritical phase and partial when they contactthe brine with dissolved H2S-CO2. Aragonite (calcium carbonate polymorph) precipitated specifically within the dry H2S-CO2 supercritical phase. CSH cristallinity is improved by partial carbonation while CSH are amorphized by complete carbonation. However, the features evidenced in this study cannot be directly related to effective features of cement as a monolith. Further studies involving cement as a monolith are necessary to ascertain textural, petrophysical, and mechanical evolution of cement.

High-sensitive factor I and C-reactive protein based biomarkers for coronary artery disease.

PubMed

Zhao, Qing; Du, Jian-Shi; Han, Dong-Mei; Ma, Ying

2014-01-01

An analysis of high-sensitive factor I and C-reactive proteins as biomarkers for coronary artery disease has been performed from 19 anticipated cohort studies that included 21,567 participants having no information about coronary artery disease. Besides, the clinical implications of statin therapy initiated due to assessment of factor I and C-reactive proteins have also been modeled during studies. The measure of risk discrimination (C-index) was increased (by 0.0101) as per the prognostic model for coronary artery disease with respect to sex, smoking status, age, blood pressure, total cholesterol level along with diabetic history characteristic parameters. The C-index was further raised by 0.0045 and 0.0053 when factor I and C-reactive proteins based information were added, respectively which finally predicted 10-year risk categories as: high (> 20%), medium (10% to < 20%), and low (< 10%) risks. We found 2,254 persons (among 15,000 adults (age ≥ 45 years)) would initially be classified as being at medium risk for coronary artery disease when only conventional risk factors were used as calculated risk. Besides, persons with a predicted risk of more than 20% as well as for persons suffering from other risk factors (i.e. diabetes), statin therapy was initiated (irrespective of their decade old predicted risk). We conclude that under current treatment guidelines assessment of factor I and C-reactive proteins levels (as biomarker) in people at medium risk for coronary artery disease could prevent one additional coronary artery disease risk over a period a decade for every 390-500 people screened.

Influence of high-temperature steam on the reactivity of CaO sorbent for CO₂ capture.

PubMed

Donat, Felix; Florin, Nicholas H; Anthony, Edward J; Fennell, Paul S

2012-01-17

Calcium looping is a high-temperature CO(2) capture technology applicable to the postcombustion capture of CO(2) from power station flue gas, or integrated with fuel conversion in precombustion CO(2) capture schemes. The capture technology uses solid CaO sorbent derived from natural limestone and takes advantage of the reversible reaction between CaO and CO(2) to form CaCO(3); that is, to achieve the separation of CO(2) from flue or fuel gas, and produce a pure stream of CO(2) suitable for geological storage. An important characteristic of the sorbent, affecting the cost-efficiency of this technology, is the decay in reactivity of the sorbent over multiple CO(2) capture-and-release cycles. This work reports on the influence of high-temperature steam, which will be present in flue (about 5-10%) and fuel (∼20%) gases, on the reactivity of CaO sorbent derived from four natural limestones. A significant increase in the reactivity of these sorbents was found for 30 cycles in the presence of steam (from 1-20%). Steam influences the sorbent reactivity in two ways. Steam present during calcination promotes sintering that produces a sorbent morphology with most of the pore volume associated with larger pores of ∼50 nm in diameter, and which appears to be relatively more stable than the pore structure that evolves when no steam is present. The presence of steam during carbonation reduces the diffusion resistance during carbonation. We observed a synergistic effect, i.e., the highest reactivity was observed when steam was present for both calcination and carbonation.

Modeling the migration of fluids in subduction zones

NASA Astrophysics Data System (ADS)

Spiegelman, M.; Wilson, C. R.; van Keken, P. E.; Hacker, B. R.

2010-12-01

Fluids play a major role in the formation of arc volcanism and the generation of continental crust. Progressive dehydration reactions in the downgoing slab release fluids to the hot overlying mantle wedge, causing flux melting and the migration of melts to the volcanic front. While the qualitative concept is well established the quantitative details of fluid release and especially that of fluid migration and generation of hydrous melting in the wedge is still poorly understood. Here we present new models of the fluid migration through the mantle wedge for subduction zones that span the spectrum of arcs worldwide. We focus on the flow of water and use an existing set of high resolution thermal and metamorphic models (van Keken et al., JGR, in review) to predict the regions of water release from the sediments, upper and lower crust, and upper most mantle. We use this water flux as input for the fluid migration calculation based on new finite element models built on advanced computational libraries (FEniCS/PETSc) for efficient and flexible solution of coupled multi-physics problems. The first generation of these models solves for the evolution of porosity and fluid-pressure/flux throughout the slab and wedge given solid flow, viscosity and thermal fields from the existing thermal models. Fluid flow in the new models depends on both permeability and the rheology of the slab-wedge system as interaction with rheological variability can induce additional pressure gradients that affect the fluid flow pathways. We will explore the sensitivity of fluid flow paths for a range of subduction zones and fluid flow parameters with emphasis on variability of the location of the volcanic arc with respect to flow paths and expected degrees of hydrous melting which can be estimated given a variety of wet-melting parameterizations (e.g. Katz et al, 2003, Kelley et al, 2010). The current models just include dehydration reactions but work continues on the next generation of models which

Near-surface Heating of Young Rift Sediment Causes Mass Production and Discharge of Reactive Dissolved Organic Matter

PubMed Central

Lin, Yu-Shih; Koch, Boris P.; Feseker, Tomas; Ziervogel, Kai; Goldhammer, Tobias; Schmidt, Frauke; Witt, Matthias; Kellermann, Matthias Y.; Zabel, Matthias; Teske, Andreas; Hinrichs, Kai-Uwe

2017-01-01

Ocean margin sediments have been considered as important sources of dissolved organic carbon (DOC) to the deep ocean, yet the contribution from advective settings has just started to be acknowledged. Here we present evidence showing that near-surface heating of sediment in the Guaymas Basin, a young extensional depression, causes mass production and discharge of reactive dissolved organic matter (DOM). In the sediment heated up to ~100 °C, we found unexpectedly low DOC concentrations in the pore waters, reflecting the combined effect of thermal desorption and advective fluid flow. Heating experiments suggested DOC production to be a rapid, abiotic process with the DOC concentration increasing exponentially with temperature. The high proportions of total hydrolyzable amino acids and presence of chemical species affiliated with activated hydrocarbons, carbohydrates and peptides indicate high reactivity of the DOM. Model simulation suggests that at the local scale, near-surface heating of sediment creates short and massive DOC discharge events that elevate the bottom-water DOC concentration. Because of the heterogeneous distribution of high heat flow areas, the expulsion of reactive DOM is spotty at any given time. We conclude that hydrothermal heating of young rift sediments alter deep-ocean budgets of bioavailable DOM, creating organic-rich habitats for benthic life. PMID:28327661

Fast intraslab fluid-flow events linked to pulses of high pore fluid pressure at the subducted plate interface

NASA Astrophysics Data System (ADS)

Taetz, Stephan; John, Timm; Bröcker, Michael; Spandler, Carl; Stracke, Andreas

2018-01-01

A better understanding of the subduction zone fluid cycle and its chemical-mechanical feedback requires in-depth knowledge about how fluids flow within and out of descending slabs. Relicts of fluid-flow systems in exhumed rocks of fossil subduction zones allow for identification of the general relationships between dehydration reactions, fluid pathway formation, the dimensions and timescales of distinct fluid flow events; all of which are required for quantitative models for fluid-induced subduction zone processes. Two types of garnet-quartz-phengite veins can be distinguished in an eclogite-facies mélange block from the Pouébo Eclogite Mélange, New Caledonia. These veins record synmetamorphic internal fluid release by mineral breakdown reactions (type I veins), and infiltration of an external fluid (type II veins) with the associated formation of a reaction selvage. The dehydration and fluid migration documented by the type I veins likely occurred on a timescale of 105-106 years, based on average subduction rates and metamorphic conditions required for mineral dehydration and fluid flow. The timeframe of fluid-rock interaction between the external fluid and the wall-rock of the type II veins is quantified using a continuous bulk-rock Li-diffusion profile perpendicular to a vein and its metasomatic selvage. Differences in Li concentration between the internal and external fluid reservoirs resulted in a distinct diffusion profile (decreasing Li concentration and increasing δ7 Li) as the reaction front propagated into the host rock. Li-chronometric constraints indicate that the timescales of fluid-rock interaction associated with type II vein formation are on the order of 1 to 4 months (0.150-0.08+0.14 years). The short-lived, pulse-like character of this process is consistent with the notion that fluid flow caused by oceanic crust dehydration at the blueschist-to-eclogite transition contributes to or even dominates episodic pore fluid pressure increases at the

Additives for High Temperature Hydraulic Fluids.

DTIC Science & Technology

HYDRAULIC FLUIDS, ADDITIVES, TRIAZINES, FERROCENES , PHOSPHINE , SULFOXIDES, SYNTHESIS(CHEMISTRY), SCIENTIFIC RESEARCH, FLUORINE COMPOUNDS, PHOSPHINE OXIDES, ORGANIC PHOSPHORUS COMPOUNDS, AMINES, HEAT RESISTANT MATERIALS.

Buckling of a beam extruded into highly viscous fluid

NASA Astrophysics Data System (ADS)

Gosselin, F. P.; Neetzow, P.; Paak, M.

2014-11-01

Inspired by microscopic Paramecia which use trichocyst extrusion to propel themselves away from thermal aggression, we propose a macroscopic experiment to study the stability of a slender beam extruded in a highly viscous fluid. Piano wires were extruded axially at constant speed in a tank filled with corn syrup. The force necessary to extrude the wire was measured to increase linearly at first until the compressive viscous force causes the wire to buckle. A numerical model, coupling a lengthening elastica formulation with resistive-force theory, predicts a similar behavior. The model is used to study the dynamics at large time when the beam is highly deformed. It is found that at large time, a large deformation regime exists in which the force necessary to extrude the beam at constant speed becomes constant and length independent. With a proper dimensional analysis, the beam can be shown to buckle at a critical length based on the extrusion speed, the bending rigidity, and the dynamic viscosity of the fluid. Hypothesizing that the trichocysts of Paramecia must be sized to maximize their thrust per unit volume as well as avoid buckling instabilities, we predict that their bending rigidity must be about 3 ×10-9N μ m2 . The verification of this prediction is left for future work.

LONG-TERM PERFORMANCE MONITORING OF PERMEABLE REACTIVE BARRIERS TO REMEDIATE CONTAMINATED GROUND WATER

EPA Science Inventory

Permeable reactive barriers (PRB's) are an alternative in-situ approach for remediating contaminated groundwater that combine subsurface fluid flow management with a passive chemical treatment zone. PRB's are being selected with increased frequency at waste sites (more than 40 f...

In situ visualisation and characterisation of the capacity of highly reactive minerals to preserve soil organic matter (SOM) in colloids at submicron scale.

PubMed

Xiao, Jian; Wen, Yongli; Li, Huan; Hao, Jialong; Shen, Qirong; Ran, Wei; Mei, Xinlan; He, Xinhua; Yu, Guanghui

2015-11-01

Mineral-organo associations (MOAs) are a mixture of identifiable biopolymers associated with highly reactive minerals and microorganisms. However, the in situ characterization and correlation between soil organic matter (SOM) and highly reactive Al and Fe minerals are still unclear for the lack of technologies, particularly in the long-term agricultural soil colloids at submicron scale. We combined several novel techniques, including nano-scale secondary ion mass spectrometry (NanoSIMS), X-ray absorption near edge structure (XANES) and confocal laser scanning microscopy (CLSM) to characterise the capacity of highly reactive Al and Fe minerals to preserve SOM in Ferralic Cambisol in south China. Our results demonstrated that: (1) highly reactive minerals were strongly related to SOM preservation, while SOM had a more significant line correlation with the highly reactive Al minerals than the highly reactive Fe minerals, according to the regions of interest correlation analyses using NanoSIMS; (2) allophane and ferrihydrite were the potential mineral species to determine the SOM preservation capability, which was evaluated by the X-ray photoelectron spectroscopy (XPS) and Fe K-edge XANES spectroscopy techniques; and (3) soil organic biopolymers with dominant compounds, such as proteins, polysaccharides and lipids, were distributed at the rough and clustered surface of MOAs with high chemical and spatial heterogeneity according to the CLSM observation. Our results also promoted the understanding of the roles played by the highly reactive Al and Fe minerals in the spatial distribution of soil organic biopolymers and SOM sequestration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identifying Thoracic Malignancies Through Pleural Fluid Biomarkers: A Predictive Multivariate Model.

PubMed

Porcel, José M; Esquerda, Aureli; Martínez-Alonso, Montserrat; Bielsa, Silvia; Salud, Antonieta

2016-03-01

The diagnosis of malignant pleural effusions may be challenging when cytological examination of aspirated pleural fluid is equivocal or noncontributory. The purpose of this study was to identify protein candidate biomarkers differentially expressed in the pleural fluid of patients with mesothelioma, lung adenocarcinoma, lymphoma, and tuberculosis (TB).A multiplex protein biochip comprising 120 biomarkers was used to determine the pleural fluid protein profile of 29 mesotheliomas, 29 lung adenocarcinomas, 12 lymphomas, and 35 tuberculosis. The relative abundance of these predetermined biomarkers among groups served to establish the differential diagnosis of: malignant versus benign (TB) effusions, lung adenocarcinoma versus mesothelioma, and lymphoma versus TB. The selected putative markers were validated using widely available commercial techniques in an independent sample of 102 patients.Significant differences were found in the protein expressions of metalloproteinase-9 (MMP-9), cathepsin-B, C-reactive protein, and chondroitin sulfate between malignant and TB effusions. When integrated into a scoring model, these proteins yielded 85% sensitivity, 100% specificity, and an area under the curve (AUC) of 0.98 for labeling malignancy in the verification sample. For lung adenocarcinoma-mesothelioma discrimination, combining CA19-9, CA15-3, and kallikrein-12 had maximal discriminatory capacity (65% sensitivity, 100% specificity, AUC 0.94); figures which also refer to the validation set. Last, cathepsin-B in isolation was only moderately useful (sensitivity 89%, specificity 62%, AUC 0.75) in separating lymphomatous and TB effusions. However, this last differentiation improved significantly when cathepsin-B was used with respect to the patient's age (sensitivity 72%, specificity 100%, AUC 0.94).In conclusion, panels of 4 (i.e., MMP-9, cathepsin-B, C-reactive protein, chondroitin sulfate), or 3 (i.e., CA19-9, CA15-3, kallikrein-12) different protein biomarkers on pleural

Effect of multiple slip on a chemically reactive MHD non-Newtonian nanofluid power law fluid flow over a stretching sheet with microorganism

NASA Astrophysics Data System (ADS)

Basir, Mohammad Faisal Mohd; Ismail, Fazreen Amira; Amirsom, Nur Ardiana; Latiff, Nur Amalina Abdul; Ismail, Ahmad Izani Md.

2017-04-01

The effect of multiple slip on a chemically reactive magnetohydrodynamic (MHD) non-Newtonian power law fluid flow over a stretching sheet with microorganism was numerically investigated. The governing partial differential equations were transformed into nonlinear ordinary differential equations using the similarity transformations developed by Lie group analysis. The reduced governing nonlinear ordinary differential equations were then numerically solved using the Runge-Kutta-Fehlberg fourth-fifth order method. Good agreement was found between the present numerical solutions with the existing published results to support the validity and the accuracy of the numerical computations. The influences of the velocity, thermal, mass and microorganism slips, the magnetic field parameter and the chemical reaction parameter on the dimensionless velocity, temperature, nanoparticle volume fraction, microorganism concentration, the distribution of the density of motile microorganisms have been illustrated graphically. The effects of the governing parameters on the physical quantities, namely, the local heat transfer rate, the local mass transfer rate and the local microorganism transfer rate were analyzed and discussed.

Final Report for''Numerical Methods and Studies of High-Speed Reactive and Non-Reactive Flows''

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

Schwendeman, D W

2002-11-20

The work carried out under this subcontract involved the development and use of an adaptive numerical method for the accurate calculation of high-speed reactive flows on overlapping grids. The flow is modeled by the reactive Euler equations with an assumed equation of state and with various reaction rate models. A numerical method has been developed to solve the nonlinear hyperbolic partial differential equations in the model. The method uses an unsplit, shock-capturing scheme, and uses a Godunov-type scheme to compute fluxes and a Runge-Kutta error control scheme to compute the source term modeling the chemical reactions. An adaptive mesh refinementmore » (AMR) scheme has been implemented in order to locally increase grid resolution. The numerical method uses composite overlapping grids to handle complex flow geometries. The code is part of the ''Overture-OverBlown'' framework of object-oriented codes [1, 2], and the development has occurred in close collaboration with Bill Henshaw and David Brown, and other members of the Overture team within CASC. During the period of this subcontract, a number of tasks were accomplished, including: (1) an extension of the numerical method to handle ''ignition and grow'' reaction models and a JWL equations of state; (2) an improvement in the efficiency of the AMR scheme and the error estimator; (3) an addition of a scheme of numerical dissipation designed to suppress numerical oscillations/instabilities near expanding detonations and along grid overlaps; and (4) an exploration of the evolution to detonation in an annulus and of detonation failure in an expanding channel.« less

An innovative computationally efficient hydromechanical coupling approach for fault reactivation in geological subsurface utilization

NASA Astrophysics Data System (ADS)

Adams, M.; Kempka, T.; Chabab, E.; Ziegler, M.

2018-02-01

Estimating the efficiency and sustainability of geological subsurface utilization, i.e., Carbon Capture and Storage (CCS) requires an integrated risk assessment approach, considering the occurring coupled processes, beside others, the potential reactivation of existing faults. In this context, hydraulic and mechanical parameter uncertainties as well as different injection rates have to be considered and quantified to elaborate reliable environmental impact assessments. Consequently, the required sensitivity analyses consume significant computational time due to the high number of realizations that have to be carried out. Due to the high computational costs of two-way coupled simulations in large-scale 3D multiphase fluid flow systems, these are not applicable for the purpose of uncertainty and risk assessments. Hence, an innovative semi-analytical hydromechanical coupling approach for hydraulic fault reactivation will be introduced. This approach determines the void ratio evolution in representative fault elements using one preliminary base simulation, considering one model geometry and one set of hydromechanical parameters. The void ratio development is then approximated and related to one reference pressure at the base of the fault. The parametrization of the resulting functions is then directly implemented into a multiphase fluid flow simulator to carry out the semi-analytical coupling for the simulation of hydromechanical processes. Hereby, the iterative parameter exchange between the multiphase and mechanical simulators is omitted, since the update of porosity and permeability is controlled by one reference pore pressure at the fault base. The suggested procedure is capable to reduce the computational time required by coupled hydromechanical simulations of a multitude of injection rates by a factor of up to 15.

LONG-TERM PERFORMANCE MONITORING OF A PERMEABLE REACTIVE BARRIER TO REMEDIATE CONTAMINATED GROUND WATER

EPA Science Inventory

Permeable reactive barriers (PRB's) are an emerging, alternative in-situ approach for remediating groundwater contamination that combine subsurface fluid flow management with a passive chemical treatment zone. The few pilot and commercial installations which have been implemented...

Modelling reactive transport in a phosphogypsum dump, Venezia, Italia

NASA Astrophysics Data System (ADS)

Calcara, Massimo; Borgia, Andrea; Cattaneo, Laura; Bartolo, Sergio; Clemente, Gianni; Glauco Amoroso, Carlo; Lo Re, Fabio; Tozzato, Elena

2013-04-01

We develop a reactive-transport porous media flow model for a phosphogypsum dump located on the intertidal deposits of the Venetian Lagoon: 1. we construct a complex conceptual and geologic model from field data using the GMS™ graphical user interface; 2. the geological model is mapped onto a rectangular MODFLOW grid; 3. using the TMT2 FORTRAN90 code we translate this grid into the MESH, INCON and GENER input files for the TOUGH2 series of codes; 4. we run TOUGH-REACT to model flow and reactive transport in the dump and the sediments below it. The model includes 3 different dump materials (phosphogypsum, bituminous and hazardous wastes) with the pores saturated by specific fluids. The sediments below the dump are formed by an intertidal sequence of calcareous sands and silts, in addition to clays and organic deposits, all of which are initially saturated with lagoon salty waters. The recharge rain-water dilutes the dump fluids. In turn, the percolates from the dump react with the underlying sediments and the sea water that saturates them. Simulation results have been compared with chemical sampled analyses. In fact, in spite of the simplicity of our model we are able to show how the pH becomes neutral at a short distance below the dump, a fact observed during aquifer monitoring. The spatial and temporal evolution of dissolution and precipitation reactions occur in our model much alike reality. Mobility of some elements, such as divalent iron, are reduced by specific and concurrent conditions of pH from near-neutrality to moderately high values and positive redox potential; opposite conditions favour mobility of potentially toxic metals such as Cr, As Cd and Pb. Vertical movement are predominant. Trend should be therefore heavily influenced by pH and Eh values. If conditions are favourable to mobility, concentration of these substances in the bottom strata could be high. However, simulation suggest that the sediments tend to reduce the transport potential of

Highly Human Immunodeficiency Virus-Exposed Seronegative Men Have Lower Mucosal Innate Immune Reactivity.

PubMed

Fulcher, Jennifer A; Romas, Laura; Hoffman, Jennifer C; Elliott, Julie; Saunders, Terry; Burgener, Adam D; Anton, Peter A; Yang, Otto O

2017-08-01

Risk of HIV acquisition varies, and some individuals are highly HIV-1-exposed, yet, persistently seronegative (HESN). The immunologic mechanisms contributing to this phenomenon are an area of intense interest. As immune activation and inflammation facilitate disease progression in HIV-1-infected persons and gastrointestinal-associated lymphoid tissue is a highly susceptible site for transmission, we hypothesized that reduced gut mucosal immune reactivity may contribute to reduced HIV-1 susceptibility in HESN men with a history of numerous rectal sexual exposures. To test this, we used ex vivo mucosal explants from freshly acquired colorectal biopsies from healthy control and HESN subjects who were stimulated with specific innate immune ligands and inactivated whole pathogens. Immune reactivity was then assessed via cytokine arrays and proteomic analysis. Mucosal immune cell compositions were quantified via immunohistochemistry. We found that explants from HESN subjects produced less proinflammatory cytokines compared with controls following innate immune stimulation; while noninflammatory cytokines were similar between groups. Proteomic analysis identified several immune response proteins to be differentially expressed between HIV-1-stimulated HESN and control explants. Immunohistochemical examination of colorectal mucosa showed similar amounts of T cells, macrophages, and dendritic cells between groups. The results of this pilot study suggest that mucosal innate immune reactivity is dampened in HESN versus control groups, despite presence of similar densities of immune cells in the colorectal mucosa. This observed modulation of the rectal mucosal immune response may contribute to lower risk of mucosal HIV-1 transmission in these individuals.

Method and apparatus for continuously referenced analysis of reactive components in solution

DOEpatents

Bostick, W.D.; Denton, M.S.; Dinsmore, S.R.

1979-07-31

A continuously referenced apparatus for measuring the concentration of a reactive chemical species in solution comprises in combination conduit means for introducing a sample solution, means for introducing one or more reactants into a sample solution, and a stream separator disposed within the conduit means for separating the sample solution into a first sample stream and a second sample stream. A reactor is disposed in fluid communication with the first sample stream. A reaction takes place between the reactants introduced and the reactive chemical species of interest, causing the consumption or production of an indicator species in the first sample stream. Measurement means such as a photometric system are disposed in communication with the first and second sample streams, and the outputs of the measurement means are compared to provide a blanked measurement of the concentration of indicator species. The apparatus is particularly suitable for measurement of isoenzymes in body tissues or fluids.

High power densities from high-temperature material interactions. [in thermionic energy conversion and metallic fluid heat pipes

NASA Technical Reports Server (NTRS)

Morris, J. F.

1981-01-01

Thermionic energy conversion (TEC) and metallic-fluid heat pipes (MFHPs), offering unique advantages in terrestrial and space energy processing by virtue of operating on working-fluid vaporization/condensation cycles that accept great thermal power densities at high temperatures, share complex materials problems. Simplified equations are presented that verify and solve such problems, suggesting the possibility of cost-effective applications in the near term for TEC and MFHP devices. Among the problems discussed are: the limitation of alkali-metal corrosion, protection against hot external gases, external and internal vaporization, interfacial reactions and diffusion, expansion coefficient matching, and creep deformation.

Low-Temperature Reactivities of Ultra-High Temperature Ceramics (Hf-X System)

DTIC Science & Technology

2005-12-01

as interacting fillers with the preceramic polymer formulations. In situ formation of the SiC phase was also evaluated as a practical approach in...led to a renewal of activities to fabricate MB2/ SiC composites as the materials of choice, because of their high thermal and oxidation resistance...HfB2/ SiC composite microstructures (and also HfC, ZrB2, and ZrC composites ) under pressureless conditions. These can be employed in reactive and

High impact strength polymers having novel nano-structures produced via reactive extrusion

NASA Astrophysics Data System (ADS)

Tortorella, Nathan Fraser

A major focus of scientists and engineers over the last century has been to increase the impact strength and therefore reduce the brittleness of materials. By altering and adding energy absorption mechanisms, brittle failure can be averted. Isotactic polypropylene (PP) is the focus of this dissertation because it is an extremely low cost, high volume, versatile plastic but behaves in a brittle manner at or below room temperature or in a notched state. Early work on impact modification of polypropylene focused on blending energy-absorbing low density elastomers and rubbers. These binary blends all had a common problem---an increase in impact strength was paralleled by a significant decrease in both elastic modulus and yield stress. Reactive extrusion processing has allowed the in-situ compatibilization of isotactic polypropylene and metallocene-catalyzed ethylene-octene copolymers (EOCs). This process involves combining both the comonomer and vector fluid approaches to grafting polyolefins. Styrene monomer and a multifunctional acrylate monomer undergo peroxide-induced copolymerization and grafting in the presence of both PP and EOC. This results in a phase separated alloy with an impact strength over 13 times that of pure polypropylene and double that of the physical blend. There is also a significant improvement in stress-strain performance when comparing the alloys to physical blend counterparts. Many researchers have categorized the necessary components to toughening polypropylene as pertaining to the amorphous phase. The alloys described in this dissertation meet the criteria put forth by these researchers, namely low density, crystallinity, and modulus of the elastomer phase, sub-micron particle diameter, close inter-particle distance, and a high degree of entanglements of both the PP matrix phase and EOC minor phase. But many people neglect to study the crystalline state of impact modified PP in conjunction with the amorphous phase. This work shows that the

Experimental and simulation studies of pore scale flow and reactive transport associated with supercritical CO2 injection into brine-filled reservoir rocks (Invited)

NASA Astrophysics Data System (ADS)

DePaolo, D. J.; Steefel, C. I.; Bourg, I. C.

2013-12-01

This talk will review recent research relating to pore scale reactive transport effects done in the context of the Department of Energy-sponsored Energy Frontier Research Center led by Lawrence Berkeley National Laboratory with several other laboratory and University partners. This Center, called the Center for Nanoscale Controls on Geologic CO2 (NCGC) has focused effort on the behavior of supercritical CO2 being injected into and/or residing as capillary trapped-bubbles in sandstone and shale, with particular emphasis on the description of nanoscale to pore scale processes that could provide the basis for advanced simulations. In general, simulation of reservoir-scale behavior of CO2 sequestration assumes a number of mostly qualitative relationships that are defensible as nominal first-order descriptions of single-fluid systems, but neglect the many complications that are associated with a two-phase or three-phase reactive system. The contrasts in properties, and the mixing behavior of scCO2 and brine provide unusual conditions for water-rock interaction, and the NCGC has investigated the underlying issues by a combination of approaches including theoretical and experimental studies of mineral nucleation and growth, experimental studies of brine films, mineral wetting properties, dissolution-precipitation rates and infiltration patterns, molecular dynamic simulations and neutron scattering experiments of fluid properties for fluid confined in nanopores, and various approaches to numerical simulation of reactive transport processes. The work to date has placed new constraints on the thickness of brine films, and also on the wetting properties of CO2 versus brine, a property that varies between minerals and with salinity, and may also change with time as a result of the reactivity of CO2-saturated brine. Mineral dissolution is dependent on reactive surface area, which can be shown to vary by a large factor for various minerals, especially when correlated with

From conservative to reactive transport under diffusion-controlled conditions

NASA Astrophysics Data System (ADS)

Babey, Tristan; de Dreuzy, Jean-Raynald; Ginn, Timothy R.

2016-05-01

We assess the possibility to use conservative transport information, such as that contained in transit time distributions, breakthrough curves and tracer tests, to predict nonlinear fluid-rock interactions in fracture/matrix or mobile/immobile conditions. Reference simulated data are given by conservative and reactive transport simulations in several diffusive porosity structures differing by their topological organization. Reactions includes nonlinear kinetically controlled dissolution and desorption. Effective Multi-Rate Mass Transfer models (MRMT) are calibrated solely on conservative transport information without pore topology information and provide concentration distributions on which effective reaction rates are estimated. Reference simulated reaction rates and effective reaction rates evaluated by MRMT are compared, as well as characteristic desorption and dissolution times. Although not exactly equal, these indicators remain very close whatever the porous structure, differing at most by 0.6% and 10% for desorption and dissolution. At early times, this close agreement arises from the fine characterization of the diffusive porosity close to the mobile zone that controls fast mobile-diffusive exchanges. At intermediate to late times, concentration gradients are strongly reduced by diffusion, and reactivity can be captured by a very limited number of rates. We conclude that effective models calibrated solely on conservative transport information like MRMT can accurately estimate monocomponent kinetically controlled nonlinear fluid-rock interactions. Their relevance might extend to more advanced biogeochemical reactions because of the good characterization of conservative concentration distributions, even by parsimonious models (e.g., MRMT with 3-5 rates). We propose a methodology to estimate reactive transport from conservative transport in mobile-immobile conditions.

The change in orientation of subsidiary shears near faults containing pore fluid under high pressure

USGS Publications Warehouse

Byerlee, J.

1992-01-01

Byerlee, J., 1992. The change in orientation of subsidiary shears near faults containing pore fluid under high pressure. In: T. Mikumo, K. Aki, M. Ohnaka, L.J. Ruff and P.K.P. Spudich (Editors), Earthquake Source Physics and Earthquake Precursors. Tectonophysics, 211: 295-303. The mechanical effects of a fault containing near-lithostatic fluid pressure in which fluid pressure decreases monotonically from the core of the fault zone to the adjacent country rock is considered. This fluid pressure distribution has mechanical implications for the orientation of subsidiary shears around a fault. Analysis shows that the maximum principal stress is oriented at a high angle to the fault in the country rock where the pore pressure is hydrostatic, and rotates to 45?? to the fault within the fault zone where the pore pressure is much higher. This analysis suggests that on the San Andreas fault, where heat flow constraints require that the coefficient of friction for slip on the fault be less than 0.1, the pore fluid pressure on the main fault is 85% of the lithostatic pressure. The observed geometry of the subsidiary shears in the creeping section of the San Andreas are broadly consistent with this model, with differences that may be due to the heterogeneous nature of the fault. ?? 1992.

Halide and Oxy-Halide Eutectic Systems for High-Performance, High-Temperature Heat Transfer Fluids (Fact Sheet)

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

Not Available

2012-12-01

The University of Arizona, Arizona Statue University (ASU), and Georgia Institute of Technology is one of the 2012 SunShot CSP R&D awardees for their Multidisciplinary University Research Initiative (MURI): High Operating Temperature (HOT) Fluids. This fact sheet explains the motivation, description, and impact of the project.

The Impact of Solid Surface Features on Fluid-Fluid Interface Configuration

NASA Astrophysics Data System (ADS)

Araujo, J. B.; Brusseau, M. L. L.

2017-12-01

Pore-scale fluid processes in geological media are critical for a broad range of applications such as radioactive waste disposal, carbon sequestration, soil moisture distribution, subsurface pollution, land stability, and oil and gas recovery. The continued improvement of high-resolution image acquisition and processing have provided a means to test the usefulness of theoretical models developed to simulate pore-scale fluid processes, through the direct quantification of interfaces. High-resolution synchrotron X-ray microtomography is used in combination with advanced visualization tools to characterize fluid distributions in natural geologic media. The studies revealed the presence of fluid-fluid interface associated with macroscopic features on the surfaces of the solids such as pits and crevices. These features and respective fluid interfaces, which are not included in current theoretical or computational models, may have a significant impact on accurate simulation and understanding of multi-phase flow, energy, heat and mass transfer processes.

Mesoporous Polymer Frameworks from End-Reactive Bottlebrush Copolymers

DOE PAGES

Altay, Esra; Nykypanchuk, Dmytro; Rzayev, Javid

2017-08-07

Reticulated nanoporous materials generated by versatile molecular framework approaches are limited to pore dimensions on the scale of the utilized rigid molecular building blocks (<5 nm). The inherent flexibility of linear polymers precludes their utilization as long framework connectors for the extension of this strategy to larger length scales. We report a method for the fabrication of mesoporous frameworks by using bottlebrush copolymers with reactive end blocks serving as rigid macromolecular interconnectors with directional reactivity. End-reactive bottlebrush copolymers with pendant alkene functionalities were synthesized by a combination of controlled radical polymerization and polymer modification protocols. Ru-catalyzed cross-metathesis cross-linking of bottlebrushmore » copolymers with two reactive end blocks resulted in the formation of polymer frameworks where isolated cross-linked domains were interconnected with bottlebrush copolymer bridges. The resulting materials were characterized by a continuous network pore structure with average pore sizes of 9–50 nm, conveniently tunable by the length of the utilized bottlebrush copolymer building blocks. As a result, the materials fabrication strategy described in this work expands the length scale of molecular framework materials and provides access to mesoporous polymers with a molecularly tunable reticulated pore structure without the need for templating, sacrificial component etching, or supercritical fluid drying.« less

The Fluids RAP

NASA Astrophysics Data System (ADS)

Nedyalkov, Ivaylo

2016-11-01

After fifteen years of experience in rap, and ten in fluid mechanics, "I am coming here with high-Reynolds-number stamina; I can beat these rap folks whose flows are... laminar." The rap relates fluid flows to rap flows. The fluid concepts presented in the song have varying complexity and the listeners/viewers will be encouraged to read the explanations on a site dedicated to the rap. The music video will provide an opportunity to share high-quality fluid visualizations with a general audience. This talk will present the rap lyrics, the vision for the video, and the strategy for outreach. Suggestions and comments will be welcomed.

High residual platelet reactivity on clopidogrel: its significance and therapeutic challenges overcoming clopidogrel resistance

PubMed Central

Alam, Samir

2013-01-01

Over the last decade, dual antiplatelet therapy has been the mainstay of the management of Acute Coronary Syndrome, with clopidogrel therapy providing clear benefits over aspirin monotherapy and becoming the agent of choice for the prevention of stent thrombosis. While newer antiplatelet agents have now become available, clopidogrel is still widely used due to its low cost and efficacy. However, many patients still experience recurrent ischemic events. A poor response of the platelets to clopidogrel, called High Residual Platelet Reactivity (HRPR), has been incriminated to account for this dilemma. Despite the absence of a universal definition of HRPR or the gold standard test to quantify it, persistent high platelet reactivity has consistently been associated with recurrence of ischemic events. Clopidogrel metabolism is highly variable, and genetics, comorbidities and drug interactions can affect it. In this article we review all definitions of HRPR, explore the available tests to quantify it, the clinical outcomes associated with it, as well as strategies that have shown success in overcoming it. PMID:24282742

Valve assembly for use with high temperature and high pressure fluids

DOEpatents

De Feo, Angelo

1982-01-01

The valve assembly for use with high temperature and high pressure fluids has inner and outer spaced shells and a valve actuator support of inner and outer spaced members which are connected at their end portions to the inner and outer shells, respectively, to extend substantially normal to the longitudinal axis of the inner shell. A layer of resilient heat insulating material covers the outer surfaces of the inner shell and the inner actuator support member and is of a thickness to only occupy part of the spaces between the inner and outer shells and inner and outer actuator support members. The remaining portion of the space between the inner and outer shells and the space between the inner and outer members is substantially filled with a body of castable, rigid refractory material. A movable valve member is disposed in the inner shell. A valve actuator assembly is supported in the valve actuator support to extend into the inner shell for connection with the movable valve member for movement of the movable valve member to positions from a fully open to a fully closed position to control flow of fluid through the inner shell. An anchor mneans is disposed adjacent opposite sides of the axis of the valve actuator support and attached to the inner shell so that relative radial movement between the inner and outer shell is permitted by the layer of resilient heat insulating material and relative longitudinal movement of the inner shell to the outer shell is permitted in opposite directions from the anchor means to thereby maintain the functional integrity of the movable valve member by providing an area of the inner shell surrounding the movable valve member longitdinally stationary, but at the same time allowing radial movement.

Breakage mechanics for granular materials in surface-reactive environments

NASA Astrophysics Data System (ADS)

Zhang, Yida; Buscarnera, Giuseppe

2018-03-01

It is known that the crushing behaviour of granular materials is sensitive to the state of the fluids occupying the pore space. Here, a thermomechanical theory is developed to link such macroscopic observations with the physico-chemical processes operating at the microcracks of individual grains. The theory relies on the hypothesis that subcritical fracture propagation at intra-particle scale is the controlling mechanism for the rate-dependent, water-sensitive compression of granular specimens. First, the fracture of uniaxially compressed particles in surface-reactive environments is studied in light of irreversible thermodynamics. Such analysis recovers the Gibbs adsorption isotherm as a central component linking the reduction of the fracture toughness of a solid to the increase of vapour concentration. The same methodology is then extended to assemblies immersed in wet air, for which solid-fluid interfaces have been treated as a separate phase. It is shown that this choice brings the solid surface energy into the dissipation equations of the granular matrix, thus providing a pathway to (i) integrate the Gibbs isotherm with the continuum description of particle assemblies and (ii) reproduce the reduction of their yield strength in presence of high relative humidity. The rate-effects involved in the propagation of cracks and the evolution of breakage have been recovered by considering non-homogenous dissipation potentials associated with the creation of surface area at both scales. It is shown that the proposed model captures satisfactorily the compression response of different types of granular materials subjected to varying relative humidity. This result was achieved simply by using parameters based on the actual adsorption characteristics of the constituting minerals. The theory therefore provides a physically sound and thermodynamically consistent framework to study the behaviour of granular solids in surface-reactive environments.

Marital Conflict, Allostatic Load, and the Development of Children's Fluid Cognitive Performance

PubMed Central

Hinnant, J. Benjamin; El-Sheikh, Mona; Keiley, Margaret; Buckhalt, Joseph A.

2013-01-01

Relations between marital conflict, children’s respiratory sinus arrhythmia (RSA), and fluid cognitive performance were examined over three years to assess allostatic processes. Participants were 251 children reporting on marital conflict, baseline RSA and RSA reactivity to a lab challenge were recorded, and fluid cognitive performance was measured using the Woodcock-Johnson III. A cross-lagged model showed that higher levels of marital conflict at age 8 predicted weaker RSA-R at age 9 for children with lower baseline RSA. A growth model showed that lower baseline RSA in conjunction with weaker RSA-R predicted the slowest development of fluid cognitive performance. Findings suggest that stress may affect development of physiological systems regulating attention, which are tied to the development of fluid cognitive performance. PMID:23534537

Zeta Potential Measurements on Solid Surfaces for in Vitro Biomaterials Testing: Surface Charge, Reactivity Upon Contact With Fluids and Protein Absorption

PubMed Central

Ferraris, Sara; Cazzola, Martina; Peretti, Veronica; Stella, Barbara; Spriano, Silvia

2018-01-01

Surface properties of biomaterials (e.g., roughness, chemical composition, charge, wettability, and hydroxylation degree) are key features to understand and control the complex interface phenomena that happens upon contact with physiological fluids. Numerous physico-chemical techniques can be used in order to investigate in depth these crucial material features. Among them, zeta potential measurements are widely used for the characterization of colloidal suspensions, but actually poorly explored in the study of solid surfaces, even if they can give significant information about surface charge in function of pH and indirectly about surface functional groups and reactivity. The aim of the present research is application of zeta potential measurements of solid surfaces for the in vitro testing of biomaterials. In particular, bare and surface modified Ti6Al4V samples have been compared in order to evaluate their isoelectric points (IEPs), surface charge at physiological pH, in vitro bioactivity [in simulated body fluid (SBF)] and protein absorption. Zeta potential titration was demonstrated as a suitable technique for the surface characterization of surface treated Ti6Al4V substrates. Significant shift of the isoelectric point was recorded after a chemical surface treatment (because of the exposition of hydroxyl groups), SBF soaking (because of apatite precipitation IEP moves close to apatite one) and protein absorption (IEP moves close to protein ones). Moreover, the shape of the curve gives information about exposed functional groups (e.g., a plateau in the basic range appears due to the exposition of acidic OH groups and in the acidic range due to exposition of basic NH2 groups). PMID:29868575

Emotional reactivity, functioning, and C-reactive protein alterations in remitted bipolar patients: Clinical relevance of a dimensional approach.

PubMed

Dargél, Aroldo A; Godin, Ophelia; Etain, Bruno; Hirakata, Vânia; Azorin, Jean-Michel; M'Bailara, Katia; Bellivier, Frank; Bougerol, Thierry; Kahn, Jean-Pierre; Passerieux, Christine; Aubin, Valerie; Courtet, Philippe; Leboyer, Marion; Henry, Chantal

2017-08-01

Inter-episode mood instability has increasingly been considered in bipolar disorder. This study aimed to investigate emotional reactivity as a major dimension for better characterizing remitted bipolar patients with subthreshold mood symptoms and functional status. This study also aimed to investigate whether high-sensitivity C-reactive protein, a marker of low-grade inflammation, could be a biological marker of emotional dysregulation in bipolar disorder (BD). Cross-sectional study of 613 subjects who met Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition criteria for BD recruited from the FondaMental Advanced Centers of Expertise in Bipolar Disorders cohort from 2009 to 2014. All patients had been in remission for at least 3 months before assessment. Patients were classified into three groups according to levels of emotional reactivity. Emotional reactivity was assessed by using the Multidimensional Assessment of Thymic States, and functional status was assessed by the Functioning Assessment Short Test. Clinical characteristics and blood sample were collected from all patients. In total, 415 (68%) patients had abnormal emotional reactivity. Independent of potential confounders, including age, gender and subthreshold mood symptoms, serum levels of high-sensitivity C-reactive protein were significantly higher in patients with emotional hyper-reactivity (median = 4.0 mg/L, interquartile range = 2.7-5.6), and with emotional hypo-reactivity (median = 3.0 mg/L, interquartile range = 1-4) compared with patients with normal emotional reactivity (median = 0.95 mg/L, interquartile range = 0.4-1.9, p < 0.001). Patients with emotional hyper-reactivity showed significant cognitive functioning impairment ( p < 0.001). Emotional reactivity appears to be a relevant dimension for better characterizing remitted bipolar patients with subthreshold mood symptoms. Levels of high-sensitivity C-reactive protein may be an

HIGH-FIDELITY SIMULATION-DRIVEN MODEL DEVELOPMENT FOR COARSE-GRAINED COMPUTATIONAL FLUID DYNAMICS

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

Hanna, Botros N.; Dinh, Nam T.; Bolotnov, Igor A.

Nuclear reactor safety analysis requires identifying various credible accident scenarios and determining their consequences. For a full-scale nuclear power plant system behavior, it is impossible to obtain sufficient experimental data for a broad range of risk-significant accident scenarios. In single-phase flow convective problems, Direct Numerical Simulation (DNS) and Large Eddy Simulation (LES) can provide us with high fidelity results when physical data are unavailable. However, these methods are computationally expensive and cannot be afforded for simulation of long transient scenarios in nuclear accidents despite extraordinary advances in high performance scientific computing over the past decades. The major issue is themore » inability to make the transient computation parallel, thus making number of time steps required in high-fidelity methods unaffordable for long transients. In this work, we propose to apply a high fidelity simulation-driven approach to model sub-grid scale (SGS) effect in Coarse Grained Computational Fluid Dynamics CG-CFD. This approach aims to develop a statistical surrogate model instead of the deterministic SGS model. We chose to start with a turbulent natural convection case with volumetric heating in a horizontal fluid layer with a rigid, insulated lower boundary and isothermal (cold) upper boundary. This scenario of unstable stratification is relevant to turbulent natural convection in a molten corium pool during a severe nuclear reactor accident, as well as in containment mixing and passive cooling. The presented approach demonstrates how to create a correction for the CG-CFD solution by modifying the energy balance equation. A global correction for the temperature equation proves to achieve a significant improvement to the prediction of steady state temperature distribution through the fluid layer.« less

LONG-TERM PERFORMANCE OF IN-SITU PERMEABLE REACTIVE BARRIERS FOR REMEDIATION OF CONTAMINATED GROUND WATER

EPA Science Inventory

Permeable reactive barriers (PRB's) are an emerging, alternative in-situ approach for remediating groundwater contamination that combine subsurface fluid flow management with a passive chemical treatment zone. The few pilot and commercial installations which have been implemented...

Numerical Modeling of Poroelastic-Fluid Systems Using High-Resolution Finite Volume Methods

NASA Astrophysics Data System (ADS)

Lemoine, Grady

Poroelasticity theory models the mechanics of porous, fluid-saturated, deformable solids. It was originally developed by Maurice Biot to model geophysical problems, such as seismic waves in oil reservoirs, but has also been applied to modeling living bone and other porous media. Poroelastic media often interact with fluids, such as in ocean bottom acoustics or propagation of waves from soft tissue into bone. This thesis describes the development and testing of high-resolution finite volume numerical methods, and simulation codes implementing these methods, for modeling systems of poroelastic media and fluids in two and three dimensions. These methods operate on both rectilinear grids and logically rectangular mapped grids. To allow the use of these methods, Biot's equations of poroelasticity are formulated as a first-order hyperbolic system with a source term; this source term is incorporated using operator splitting. Some modifications are required to the classical high-resolution finite volume method. Obtaining correct solutions at interfaces between poroelastic media and fluids requires a novel transverse propagation scheme and the removal of the classical second-order correction term at the interface, and in three dimensions a new wave limiting algorithm is also needed to correctly limit shear waves. The accuracy and convergence rates of the methods of this thesis are examined for a variety of analytical solutions, including simple plane waves, reflection and transmission of waves at an interface between different media, and scattering of acoustic waves by a poroelastic cylinder. Solutions are also computed for a variety of test problems from the computational poroelasticity literature, as well as some original test problems designed to mimic possible applications for the simulation code.

High Throughput ELISAs to Measure a Unique Glycan on Transferrin in Cerebrospinal Fluid: A Possible Extension toward Alzheimer's Disease Biomarker Development

PubMed Central

Shirotani, Keiro; Futakawa, Satoshi; Nara, Kiyomitsu; Hoshi, Kyoka; Saito, Toshie; Tohyama, Yuriko; Kitazume, Shinobu; Yuasa, Tatsuhiko; Miyajima, Masakazu; Arai, Hajime; Kuno, Atsushi; Narimatsu, Hisashi; Hashimoto, Yasuhiro

2011-01-01

We have established high-throughput lectin-antibody ELISAs to measure different glycans on transferrin (Tf) in cerebrospinal fluid (CSF) using lectins and an anti-transferrin antibody (TfAb). Lectin blot and precipitation analysis of CSF revealed that PVL (Psathyrella velutina lectin) bound an unique N-acetylglucosamine-terminated N-glycans on “CSF-type” Tf whereas SSA (Sambucus sieboldiana agglutinin) bound α2,6-N-acetylneuraminic acid-terminated N-glycans on “serum-type” Tf. PVL-TfAb ELISA of 0.5 μL CSF samples detected “CSF-type” Tf but not “serum-type” Tf whereas SSA-TfAb ELISA detected “serum-type” Tf but not “CSF-type” Tf, demonstrating the specificity of the lectin-TfAb ELISAs. In idiopathic normal pressure hydrocephalus (iNPH), a senile dementia associated with ventriculomegaly, amounts of the SSA-reactive Tf were significantly higher than in non-iNPH patients, indicating that Tf glycan analysis by the high-throughput lectin-TfAb ELISAs could become practical diagnostic tools for iNPH. The lectin-antibody ELISAs of CSF proteins might be useful for diagnosis of the other neurological diseases. PMID:21876827

Modeling the Migration of Fluids in Subduction Zones

NASA Astrophysics Data System (ADS)

Wilson, C. R.; Spiegelman, M.; Van Keken, P. E.; Vrijmoed, J. C.; Hacker, B. R.

2011-12-01

Fluids play a major role in the formation of arc volcanism and the generation of continental crust. Progressive dehydration reactions in the downgoing slab release fluids to the hot overlying mantle wedge, causing flux melting and the migration of melts to the volcanic front. While the qualitative concept is well established, the quantitative details of fluid release and especially that of fluid migration and generation of hydrous melting in the wedge is still poorly understood. Here we present new models of the fluid migration through the mantle wedge for subduction zones. We use an existing set of high resolution metamorphic models (van Keken et al, 2010) to predict the regions of water release from the sediments, upper and lower crust, and upper most mantle. We use this water flux as input for the fluid migration calculation based on new finite element models built on advanced computational libraries (FEniCS/PETSc) for efficient and flexible solution of coupled multi-physics problems. The first generation of one-way coupled models solves for the evolution of porosity and fluid-pressure/flux throughout the slab and wedge given solid flow, viscosity and thermal fields from separate solutions to the incompressible Stokes and energy equations in the mantle wedge. These solutions are verified by comparing to previous benchmark studies (van Keken et al, 2008) and global suites of thermal subduction models (Syracuse et al, 2010). Fluid flow depends on both permeability and the rheology of the slab-wedge system as interaction with rheological variability can induce additional pressure gradients that affect the fluid flow pathways. These non-linearities have been shown to explain laboratory-scale observations of melt band orientation in labratory experiments and numerical simulations of melt localization in shear bands (Katz et al 2006). Our second generation of models dispense with the pre-calculation of incompressible mantle flow and fully couple the now compressible

Reactive flow models of the Anarraaq Zn-Pb-Ag deposit, Red Dog district, Alaska

USGS Publications Warehouse

Schardt, C.; Garven, G.; Kelley, K.D.; Leach, D.L.

2008-01-01

The Red Dog ore deposit district in the Brooks Range of northern Alaska is host to several high-grade, shale-hosted Zn + Pb deposits. Due to the complex history and deformation of these ore deposits, the geological and hydrological conditions at the time of formation are poorly understood. Using geological observations and fluid inclusion data as constraints, numerical heat and fluid flow simulations of the Anarraaq ore deposit environment and coupled reactive flow simulations of a section of the ore body were conducted to gain more insight into the conditions of ore body formation. Results suggest that the ore body and associated base metal zonation may have formed by the mixing of oxidized, saline, metal-bearing hydrothermal fluids (<200??C) with reducing, HS-rich pore fluids within radiolarite-rich host rocks. Sphalerite and galena concentrations and base metal sulfide distribution are primarily controlled by the nature of the pore fluids, i.e., the extent and duration of the HS- source. Forward modeling results also predict the distribution of pyrite and quartz in agreement with field observations and indicate a reaction front moving from the initial mixing interface into the radiolarite rocks. Heuristic mass calculations suggest that ore grades and base metal accumulation comparable to those found in the field (18% Zn, 5% Pb) are predicted to be reached after about 0.3 My for initial conditions (30 ppm Zn, 3 ppm Pb; 20% deposition efficiency). ?? Springer-Verlag 2008.

Mapping Fluid Injection and Associated Induced Seismicity Using InSAR Analysis

NASA Astrophysics Data System (ADS)

Thorpe, S. D.; Tiampo, K. F.

2016-12-01

In recent years there has been a rise in unconventional oil and gas production in western North America which has been coupled with an increase in the number of earthquakes recorded in these regions, commonly referred to as "induced seismicity" (Ellsworth, 2013). As fluid is pumped into the subsurface during hydraulic fracturing or fluid disposal, the state of stress within the subsurface changes, potentially reactivating pre-existing faults and/or causing subsidence or uplift of the surface. This anthropogenic surface deformation also provides significant hazard to communities and structures surrounding these hydraulic fracturing or fluid disposal sites (Barnhart et al., 2014; Shirzaei et al., 2016). This study aims to relate, both spatially and temporally, this surface deformation to hydraulic fracturing and fluid disposal operations in Alberta (AB) and British Columbia (BC) using Differential Interferometric Synthetic Aperture Radar (InSAR) analysis. Satellite-based geodetic methods such as InSAR provide frequent measurements of ground deformation at high spatial resolution. Based on locations of previously identified induced seismicity in areas throughout AB and BC, images were acquired for multiple locations from the Canadian RADARSAT-2 satellite, including Fort St. John and Fox Creek, AB (Atkinson et al., 2016). Using advanced processing techniques, these images then were stacked to generate coherent interferograms. We present results from this processing as a set of time series that are correlated with both hydraulic fracturing and fluid disposal sites at each location. These results reveal the temporal and spatial relationship between well injection activity and associated induced seismicity in western Canada. Future work will utilise these time series to model subsurface fluid flow, providing important information regarding the nature of the subsurface structure and associated aquifer due to fluid injection and withdrawal.

Role of the Short Distance Order in Glass Reactivity

PubMed Central

2018-01-01

In 2005, our group described for the first time the structural characterization at the atomic scale of bioactive glasses and the influence of the glasses’ nanostructure in their reactivity in simulated body fluids. In that study, two bioactive sol-gel glasses with composition 80%SiO2–20%CaO and 80%SiO2–17%CaO–3%P2O5 (in mol-%) were characterized by High-Resolution Transmission Electron Microscopy (HRTEM). Such characterization revealed unknown features of the glasses’ structure at the local scale that allowed the understanding of their different in vitro behaviors as a consequence of the presence or absence of P2O5. Since then, the nanostructure of numerous bioactive glasses, including melt-prepared, sol-gel derived, and mesoporous glasses, was investigated by HRTEM, Nuclear Magnetic Resonance (NMR) spectroscopy, Molecular Dynamics (MD) simulations, and other experimental techniques. These studies have shown that although glasses are amorphous solids, a certain type of short distance order, which greatly influences the in vitro and in vivo reactivity, is always present. This paper reviews the most significant advances in the understanding of bioactive glasses that took place in the last years as a result of the growing knowledge of the glasses’ nanostructure. PMID:29534481

Carbonation by fluid-rock interactions at high-pressure conditions: Implications for carbon cycling in subduction zones

NASA Astrophysics Data System (ADS)

Piccoli, Francesca; Vitale Brovarone, Alberto; Beyssac, Olivier; Martinez, Isabelle; Ague, Jay J.; Chaduteau, Carine

2016-07-01

Carbonate-bearing lithologies are the main carbon carrier into subduction zones. Their evolution during metamorphism largely controls the fate of carbon, regulating its fluxes between shallow and deep reservoirs. Recent estimates predict that almost all subducted carbon is transferred into the crust and lithospheric mantle during subduction metamorphism via decarbonation and dissolution reactions at high-pressure conditions. Here we report the occurrence of eclogite-facies marbles associated with metasomatic systems in Alpine Corsica (France). The occurrence of these marbles along major fluid-conduits as well as textural, geochemical and isotopic data indicating fluid-mineral reactions are compelling evidence for the precipitation of these carbonate-rich assemblages from carbonic fluids during metamorphism. The discovery of metasomatic marbles brings new insights into the fate of carbonic fluids formed in subducting slabs. We infer that rock carbonation can occur at high-pressure conditions by either vein-injection or chemical replacement mechanisms. This indicates that carbonic fluids produced by decarbonation reactions and carbonate dissolution may not be directly transferred to the mantle wedge, but can interact with slab and mantle-forming rocks. Rock-carbonation by fluid-rock interactions may have an important impact on the residence time of carbon and oxygen in subduction zones and lithospheric mantle reservoirs as well as carbonate isotopic signatures in subduction zones. Furthermore, carbonation may modulate the emission of CO2 at volcanic arcs over geological time scales.

Prescribed Velocity Gradients for Highly Viscous SPH Fluids with Vorticity Diffusion.

PubMed

Peer, Andreas; Teschner, Matthias

2017-12-01

Working with prescribed velocity gradients is a promising approach to efficiently and robustly simulate highly viscous SPH fluids. Such approaches allow to explicitly and independently process shear rate, spin, and expansion rate. This can be used to, e.g., avoid interferences between pressure and viscosity solvers. Another interesting aspect is the possibility to explicitly process the vorticity, e.g., to preserve the vorticity. In this context, this paper proposes a novel variant of the prescribed-gradient idea that handles vorticity in a physically motivated way. In contrast to a less appropriate vorticity preservation that has been used in a previous approach, vorticity is diffused. The paper illustrates the utility of the vorticity diffusion. Therefore, comparisons of the proposed vorticity diffusion with vorticity preservation and additionally with vorticity damping are presented. The paper further discusses the relation between prescribed velocity gradients and prescribed velocity Laplacians which improves the intuition behind the prescribed-gradient method for highly viscous SPH fluids. Finally, the paper discusses the relation of the proposed method to a physically correct implicit viscosity formulation.

Effects of solid/liquid phase fractionation on pH and aqueous species molality in subduction zone fluids

NASA Astrophysics Data System (ADS)

Zhong, X.; Galvez, M. E.

2017-12-01

Metamorphic fluids are a crucial ingredient of geodynamic evolution, i.e. heat transfer, rock mechanics and metamorphic/metasomatic reactions. During crustal evolution at elevated P and T, rock forming components can be effectively fractionated from the reactive rock system by at least two processes: 1. extraction from porous rocks by liquid phases such as solute-bearing (e.g. Na+, Mg2+) aqueous fluids or partial melts. 2. isolation from effective bulk rock composition due to slow intragranular diffusion in high-P refractory phases such as garnet. The effect of phase fractionation (garnet, partial melt and aqueous species) on fluid - rock composition and properties remain unclear, mainly due to a high demand in quantitative computations of the thermodynamic interactions between rocks and fluids over a wide P-T range. To investigate this problem, we build our work on an approach initially introduced by Galvez et al., (2015) with new functionalities added in a MATLAB code (Rubisco). The fluxes of fractionated components in fluid, melt and garnet are monitored along a typical prograde P-T path for a model crustal pelite. Some preliminary results suggest a marginal effect of fractionated aqueous species on fluid and rock properties (e.g. pH, composition), but the corresponding fluxes are significant in the context of mantle wedge metasomatism. Our work provides insight into the role of high-P phase fractionation on mass redistribution between the surface and deep Earth in subduction zones. Existing limitations relevant to our liquid/mineral speciation/fractionation model will be discussed as well. ReferencesGalvez, M.E., Manning, C.E., Connolly, J.A.D., Rumble, D., 2015. The solubility of rocks in metamorphic fluids: A model for rock-dominated conditions to upper mantle pressure and temperature. Earth Planet. Sci. Lett. 430, 486-498.

Modelling induced seismicity due to fluid injection

NASA Astrophysics Data System (ADS)

Murphy, S.; O'Brien, G. S.; Bean, C. J.; McCloskey, J.; Nalbant, S. S.

2011-12-01

Injection of fluid into the subsurface alters the stress in the crust and can induce earthquakes. The science of assessing the risk of induced seismicity from such ventures is still in its infancy despite public concern. We plan to use a fault network model in which stress perturbations due to fluid injection induce earthquakes. We will use this model to investigate the role different operational and geological factors play in increasing seismicity in a fault system due to fluid injection. The model is based on a quasi-dynamic relationship between stress and slip coupled with a rate and state fiction law. This allows us to model slip on fault interfaces over long periods of time (i.e. years to 100's years). With the use of the rate and state friction law the nature of stress release during slipping can be altered through variation of the frictional parameters. Both seismic and aseismic slip can therefore be simulated. In order to add heterogeneity along the fault plane a fractal variation in the frictional parameters is used. Fluid injection is simulated using the lattice Boltzmann method whereby pore pressure diffuses throughout a permeable layer from the point of injection. The stress perturbation this causes on the surrounding fault system is calculated using a quasi-static solution for slip dislocation in an elastic half space. From this model we can generate slip histories and seismicity catalogues covering 100's of years for predefined fault networks near fluid injection sites. Given that rupture is a highly non-linear process, comparison between models with different input parameters (e.g. fault network statistics and injection rates) will be based on system wide features (such as the Gutenberg-Richter b-values), rather than specific seismic events. Our ultimate aim is that our model produces seismic catalogues similar to those observed over real injection sites. Such validation would pave the way to probabilistic estimation of reactivation risk for

Stability and reactivity of dimethylethoxysilane

NASA Technical Reports Server (NTRS)

Johnson, Richard E.; Ford, Douglas I.

1992-01-01

Dimethylethoxysilane (DMES) is currently used to treat the High-temperature Reusable Surface Insulation (HRSI) shuttle tiles in order to provide a hydrophobic surface on the silica. DMES is a volatile, reactive silane that incorporates two reactive sites, the ethoxy group and the silica-hydride group. The work reported in this paper focused on the reactivity of these two groups with silica, water, quantitative reagents, and within DMES itself.

Titanium-alloy, metallic-fluid heat pipes for space service

NASA Technical Reports Server (NTRS)

Morris, J. F.

1979-01-01

Reactivities of titanium limit its long-term terrestrial use for unprotected heat-pipe envelopes to about 870 K (1100 F). But this external thermochemical limitation disappears when considerations shift to space applications. In such hard-vacuum utilization much higher operating temperatures are possible. Primary restrictions in space environment result from vaporization, thermal creep, and internal compatibilities. Unfortunately, a respected head-pipe reference indicates that titanium is compatible only with cesium from the alkali-metal working-fluid family. This problem and others are subjects of the present paper which advocates titanium-alloy, metallic-fluid heat pipes for long-lived, weight-effective space service between 500 and 1300 K (440 and 1880 F).

Evidence for greater cue reactivity among low-dependent vs. high-dependent smokers.

PubMed

Watson, Noreen L; Carpenter, Matthew J; Saladin, Michael E; Gray, Kevin M; Upadhyaya, Himanshu P

2010-07-01

Cue reactivity paradigms are well-established laboratory procedures used to examine subjective craving in response to substance-related cues. For smokers, the relationship between nicotine dependence and cue reactivity has not been clearly established. The main aim of the present study was to further examine this relationship. Participants (N=90) were between the ages 18-40 and smoked > or =10 cigarettes per day. Average nicotine dependence (Fagerström Test for Nicotine Dependence; FTND) at baseline was 4.9 (SD=2.1). Participants completed four cue reactivity sessions consisting of two in vivo cues (smoking and neutral) and two affective imagery cues (stressful and relaxed), all counterbalanced. Craving in response to cues was assessed following each cue exposure using the Questionnaire of Smoking Urges-Brief (QSU-B). Differential cue reactivity was operationally defined as the difference in QSU scores between the smoking and neutral cues, and between the stressful and relaxed cues. Nicotine dependence was significantly and negatively associated with differential cue reactivity scores in regard to hedonic craving (QSU factor 1) for both in vivo and imagery cues, such that those who had low FTND scores demonstrated greater differential cue reactivity than those with higher FTND scores (beta=-.082; p=.037; beta=-.101; p=.023, respectively). Similar trends were found for the Total QSU and for negative reinforcement craving (QSU factor 2), but did not reach statistical significance. Under partially sated conditions, less dependent smokers may be more differentially cue reactive to smoking cues as compared to heavily dependent smokers. These findings offer methodological and interpretative implications for cue reactivity studies. 2010 Elsevier Ltd. All rights reserved.

Cr(III) solubility in aqueous fluids at high pressures and temperatures

NASA Astrophysics Data System (ADS)

Watenphul, Anke; Schmidt, Christian; Jahn, Sandro

2014-02-01

frequencies in the range of the two strongest experimentally observed Raman bands, whereas Cr-O stretching vibrations of hydroxy-chloride complexes occur at wavenumbers above 400 cm-1. Solubility and complexation of Cr(III) depend strongly on the activities of Cl- and H+. At high H+ and Cl- activity, the results are consistent with CrCl(H2O)0-2-1-0 complexes as major Cr(III) species, the Cr coordination number of which increases with pressure by becoming more aquated. At low Cl- activity, i.e. in our study at high-temperature low-pressure conditions, the data indicate mixed CrClx((OH)z3-x-z complexes with Cl-Cr ratios less than three. In situ μ-XRF solubility experiments conducted with eskolaite + (H2O + 29 mass% Na2CO3) and kosmochlor + (H2O + 44 mass% Na2Si3O7) resulted in dissolved Cr concentrations at or below the detection limit of 500 ppm. Thus, acidic chloridic fluids seem to be more efficient agents for Cr(III) mobilization and transport at crustal conditions than aqueous alkali carbonate or silicate solutions.

Evaluation of serum and gingival crevicular fluid C-reactive protein and IL-6 levels in patients with periodontitis and transient ischemic attacks.

PubMed

Haba, Danisia; Teslaru, Silvia; Ungureanu, Didona; Hodorog, Diana; Alecu, C; Benghiac, Ana Gabriela; Zetu, L; Ancuţa, Codrina; Ancuţa, E; Nemţoi, A; Iordache, Cristina

2011-01-01

Recent advances have suggested that periodontitis (PD), the paradigm of chronic infection in dental pathology, shares several pathogenic pathways with cardio- and cerebro-vascular disorders (CVD), based on inflammatory mediators including IL-1, IL-6, TNF-α. To assess pro-inflammatory biomarkers (C-reactive protein - CRP, IL-6) in serum and gingival crevicular fluid (GCF) in patients with PD and with transient ischemic attacks (TIAs). Prospective observational study on 143 patients classified as follows: 40 healthy subjects (group A), 50 PD patients (group B) and 53 PD-TIAs patients (group C). The predefined assessment protocol has included: current medical data, risk factors for CRP changes, periodontal status (clinical, orthopantomography, Schei Ruler technique), inflammatory biomarkers (CRP, IL-6). High serum CRP and IL-6 have been reported in both TIAs and PD, while statistically significant increase in GCF CRP only in PD-TIAs (p<0.05). Moreover, both generalized and localized chronic PD may be at higher risk for CVD, since CRP level was higher in these subgroups. However, no significant differences were reported in serum IL-6 between generalized and localized PD. A score function was demonstrated, including bone loss degree, bleeding index, collection site depth, serum and GCF IL-6 and CRP, tooth loss, allowing the classification of PD based on risk for developing TIAs. CRP and IL-6 are commonly involved in the pathways of PD and TIAs. Interdisciplinary assessment should be promoted in order to implement the stratification of PD patients according to the risk for TIAs as suggested by the proposed algorithm.

Design and testing of high temperature micro-ORC test stand using Siloxane as working fluid

NASA Astrophysics Data System (ADS)

Turunen-Saaresti, Teemu; Uusitalo, Antti; Honkatukia, Juha

2017-03-01

Organic Rankine Cycle is a mature technology for many applications e.g. biomass power plants, waste heat recovery and geothermal power for larger power capacity. Recently more attention is paid on an ORC utilizing high temperature heat with relatively low power. One of the attractive applications of such ORCs would be utilization of waste heat of exhaust gas of combustion engines in stationary and mobile applications. In this paper, a design procedure of the ORC process is described and discussed. The analysis of the major components of the process, namely the evaporator, recuperator, and turbogenerator is done. Also preliminary experimental results of an ORC process utilizing high temperature exhaust gas heat and using siloxane MDM as a working fluid are presented and discussed. The turbine type utilized in the turbogenerator is a radial inflow turbine and the turbogenerator consists of the turbine, the electric motor and the feed pump. Based on the results, it was identified that the studied system is capable to generate electricity from the waste heat of exhaust gases and it is shown that high molecular weight and high critical temperature fluids as the working fluids can be utilized in high-temperature small-scale ORC applications. 5.1 kW of electric power was generated by the turbogenerator.

Characterization of stratification for an opaque highly stable magnetorheological fluid using vertical axis inductance monitoring system

NASA Astrophysics Data System (ADS)

Xie, Lei; Choi, Young-Tai; Liao, Chang-Rong; Wereley, Norman M.

2015-05-01

A key requirement for the commercialization of various magnetorheological fluid (MRF)-based applications is sedimentation stability. In this study, a high viscosity linear polysiloxane (HVLP), which has been used for shock absorbers in heavy equipment, is proposed as a new carrier fluid in highly stable MRFs. The HVLP is known to be a thixotropic (i.e., shear thinning) fluid that shows very high viscosity at very low shear rate and low viscosity at higher shear rate. In this study, using the shear rheometer, the significant thixotropic behavior of the HVLP was experimentally confirmed. In addition, a HVLP carrier fluid-based MRF (HVLP MRF) with 26 vol. % was synthesized and its sedimentation characteristics were experimentally investigated. But, because of the opacity of the HVLP MRF, no mudline can be visually observed. Hence, a vertical axis inductance monitoring system (VAIMS) applied to a circular column of fluid was used to evaluate sedimentation behavior by correlating measured inductance with the volume fraction of dispersed particles (i.e., Fe). Using the VAIMS, Fe concentration (i.e., volume fraction) was monitored for 28 days with a measurement taken every four days, as well as one measurement after 96 days to characterize long-term sedimentation stability. Finally, the concentration of the HVLP MRF as a function of the depth in the column and time, as well as the concentration change versus the depth in the column, are presented and compared with those of a commercially available MRF (i.e., Lord MRF-126CD).

Improving the accuracy of synovial fluid analysis in the diagnosis of prosthetic joint infection with simple and inexpensive biomarkers: C-reactive protein and adenosine deaminase.

PubMed

Sousa, R; Serrano, P; Gomes Dias, J; Oliveira, J C; Oliveira, A

2017-03-01

The aims of this study were to increase the diagnostic accuracy of the analysis of synovial fluid in the differentiation of prosthetic joint infection (PJI) by the addition of inexpensive biomarkers such as the levels of C-reactive protein (CRP), adenosine deaminase (ADA), alpha-2-macrogloblulin (α2M) and procalcitonin. Between January 2013 and December 2015, synovial fluid and removed implants were requested from 143 revision total joint arthroplasties. A total of 55 patients met inclusion criteria of the receipt of sufficient synovial fluid, tissue samples and removed implants for analysis. The diagnosis of PJI followed the definition from a recent International Consensus Meeting to create two groups of patients; septic and aseptic. Using receiver operating characteristic curves we determined the cutoff values and diagnostic accuracy for each marker. There were 23 PJIs and 32 patients with aseptic loosening. The levels of total leucocyte count, proportion of polymorphonuclear leucocytes (PMNs), CRP, ADA and α2M in the synovial fluid were all significantly higher in those with a PJI than in those with aseptic loosening. The levels of procalcitonin were comparable in the two groups. Cutoff values for the optimal performance in the diagnosis of infection were: total leucocyte count > 1463 cells/μL (sensitivity (Sens) 100%, specificity (Spec) 71.9%, positive predictive value (PPV) 71.9%, negative predictive value (NPV) 100%); proportion of PMNs > 81% (Sens 78.3%, Spec 75.0%, PPV 69.2%, NPV 82.8%); CRP > 6.7mg/L (Sens 78.3%, Spec 93.8%, PPV 90.0%, NPV 85.7%); ADA > 61U/L (Sens 78.3%, Spec 96.9%, PPV 94.7%, NPV 86.1%) and α2M > 958 mg/L (Sens 47.8%, Spec 96.9%, PPV 91.7%, NPV 72.1%). The addition of a raised level of CRP or ADA to the total leukocyte count increased the specificity: total leukocyte count > 1463 cells/μL and CRP > 6.7mg/L (Sens 78.3%, Spec 100%, PPV 100%, NPV 86.5%) or with ADA > 61U/L (Sens 78.3%, Spec 96.9%, PPV 94.7%, NPV 86.1%). The total

A Fluid-driven Earthquake Cycle, Omori's Law, and Fluid-driven Aftershocks

NASA Astrophysics Data System (ADS)

Miller, S. A.

2015-12-01

Few models exist that predict the Omori's Law of aftershock rate decay, with rate-state friction the only physically-based model. ETAS is a probabilistic model of cascading failures, and is sometimes used to infer rate-state frictional properties. However, the (perhaps dominant) role of fluids in the earthquake process is being increasingly realised, so a fluid-based physical model for Omori's Law should be available. In this talk, I present an hypothesis for a fluid-driven earthquake cycle where dehydration and decarbonization at depth provides continuous sources of buoyant high pressure fluids that must eventually make their way back to the surface. The natural pathway for fluid escape is along plate boundaries, where in the ductile regime high pressure fluids likely play an integral role in episodic tremor and slow slip earthquakes. At shallower levels, high pressure fluids pool at the base of seismogenic zones, with the reservoir expanding in scale through the earthquake cycle. Late in the cycle, these fluids can invade and degrade the strength of the brittle crust and contribute to earthquake nucleation. The mainshock opens permeable networks that provide escape pathways for high pressure fluids and generate aftershocks along these flow paths, while creating new pathways by the aftershocks themselves. Thermally activated precipitation then seals up these pathways, returning the system to a low-permeability environment and effective seal during the subsequent tectonic stress buildup. I find that the multiplicative effect of an exponential dependence of permeability on the effective normal stress coupled with an Arrhenius-type, thermally activated exponential reduction in permeability results in Omori's Law. I simulate this scenario using a very simple model that combines non-linear diffusion and a step-wise increase in permeability when a Mohr Coulomb failure condition is met, and allow permeability to decrease as an exponential function in time. I show very

Fluid jet electric discharge source

DOEpatents

Bender, Howard A [Ripon, CA

2006-04-25

A fluid jet or filament source and a pair of coaxial high voltage electrodes, in combination, comprise an electrical discharge system to produce radiation and, in particular, EUV radiation. The fluid jet source is composed of at least two serially connected reservoirs, a first reservoir into which a fluid, that can be either a liquid or a gas, can be fed at some pressure higher than atmospheric and a second reservoir maintained at a lower pressure than the first. The fluid is allowed to expand through an aperture into a high vacuum region between a pair of coaxial electrodes. This second expansion produces a narrow well-directed fluid jet whose size is dependent on the size and configuration of the apertures and the pressure used in the reservoir. At some time during the flow of the fluid filament, a high voltage pulse is applied to the electrodes to excite the fluid to form a plasma which provides the desired radiation; the wavelength of the radiation being determined by the composition of the fluid.

Estimation of reactive surface area using a combined method of laboratory analyses and digital image processing

NASA Astrophysics Data System (ADS)

Ma, Jin; Kong, Xiang-Zhao; Saar, Martin O.

2017-04-01

Fluid-rock interactions play an important role in the engineering processes such as chemical stimulation of enhanced geothermal systems and carbon capture, utilization, and storage. However, these interactions highly depend on the accessible reactive surface area of the minerals that are generally poorly constrained for natural geologic samples. In particular, quantifying surface area of each reacting mineral within whole rock samples is challenging due to the heterogeneous distribution of minerals and pore space. In this study, detailed laboratory analyses were performed on sandstone samples from deep geothermal sites in Lithuania. We measure specific surface area of whole rock samples using a gas adsorption method (so-called B.E.T.) with N2 at a temperature of 77.3K. We also quantify their porosity and pore size distribution by a Helium gas pycnometer and a Hg porosimetry, respectively. Rock compositions are determined by a combination of X-ray fluorescence (XRF) and quantitative scanning electron microscopy (SEM) - Energy-dispersive X-ray spectroscopy (EDS), which are later geometrically mapped on images of two-dimensional SEM- Backscattered electrons (BSE) with a resolution of 1.2 μm and three-dimensional micro-CT with a resolution of 10.3 μm to produce a digital mineral map for further constraining the accessibility of reactive minerals. Moreover, we attempt to link the whole rock porosity, pore size distribution, and B.E.T. specific surface area with the digital mineral maps. We anticipate these necessary analyses to provide in-depth understanding of fluid sample chemistry from later hydrothermal reactive flow-through experiments on whole rock samples at elevated pressure and temperature.

Fluidizable zinc titanate materials with high chemical reactivity and attrition resistance

DOEpatents

Gupta, Raghubir P.; Gangwal, Santosh K.; Jain, Suresh C.

1993-01-01

Highly durable and chemically reactive zinc titanate materials are prepared in a particle size range of 50 to 400 .mu.m suitable for a fluidized-bed reactor for removing reduced sulfur species in a gaseous form by granulating a mixture of fine zinc oxide and titanium oxide with inorganic and organic binders and by optional additions of small amounts of activators such as CoO and MoO.sub.3 ; and then indurating it at 800.degree. to 900.degree. C. for a time sufficient to produce attrition-resistant granules.

Fluidizable zinc titanate materials with high chemical reactivity and attrition resistance

DOEpatents

Gupta, R.P.; Gangwal, S.K.; Jain, S.C.

1993-10-19

Highly durable and chemically reactive zinc titanate materials are prepared in a particle size range of 50 to 400 [mu]m suitable for a fluidized-bed reactor for removing reduced sulfur species in a gaseous form by granulating a mixture of fine zinc oxide and titanium oxide with inorganic and organic binders and by optional additions of small amounts of activators such as CoO and MoO[sub 3]; and then indurating it at 800 to 900 C for a time sufficient to produce attrition-resistant granules.

Fluid/Structure Interaction Studies of Aircraft Using High Fidelity Equations on Parallel Computers

NASA Technical Reports Server (NTRS)

Guruswamy, Guru; VanDalsem, William (Technical Monitor)

1994-01-01

Abstract Aeroelasticity which involves strong coupling of fluids, structures and controls is an important element in designing an aircraft. Computational aeroelasticity using low fidelity methods such as the linear aerodynamic flow equations coupled with the modal structural equations are well advanced. Though these low fidelity approaches are computationally less intensive, they are not adequate for the analysis of modern aircraft such as High Speed Civil Transport (HSCT) and Advanced Subsonic Transport (AST) which can experience complex flow/structure interactions. HSCT can experience vortex induced aeroelastic oscillations whereas AST can experience transonic buffet associated structural oscillations. Both aircraft may experience a dip in the flutter speed at the transonic regime. For accurate aeroelastic computations at these complex fluid/structure interaction situations, high fidelity equations such as the Navier-Stokes for fluids and the finite-elements for structures are needed. Computations using these high fidelity equations require large computational resources both in memory and speed. Current conventional super computers have reached their limitations both in memory and speed. As a result, parallel computers have evolved to overcome the limitations of conventional computers. This paper will address the transition that is taking place in computational aeroelasticity from conventional computers to parallel computers. The paper will address special techniques needed to take advantage of the architecture of new parallel computers. Results will be illustrated from computations made on iPSC/860 and IBM SP2 computer by using ENSAERO code that directly couples the Euler/Navier-Stokes flow equations with high resolution finite-element structural equations.

Computational and analytical methods in nonlinear fluid dynamics

NASA Astrophysics Data System (ADS)

Walker, James

1993-09-01

The central focus of the program was on the application and development of modern analytical and computational methods to the solution of nonlinear problems in fluid dynamics and reactive gas dynamics. The research was carried out within the Division of Engineering Mathematics in the Department of Mechanical Engineering and Mechanics and principally involved Professors P.A. Blythe, E. Varley and J.D.A. Walker. In addition. the program involved various international collaborations. Professor Blythe completed work on reactive gas dynamics with Professor D. Crighton FRS of Cambridge University in the United Kingdom. Professor Walker and his students carried out joint work with Professor F.T. Smith, of University College London, on various problems in unsteady flow and turbulent boundary layers.

Theoretical fluid dynamics

NASA Astrophysics Data System (ADS)

Shivamoggi, B. K.

This book is concerned with a discussion of the dynamical behavior of a fluid, and is addressed primarily to graduate students and researchers in theoretical physics and applied mathematics. A review of basic concepts and equations of fluid dynamics is presented, taking into account a fluid model of systems, the objective of fluid dynamics, the fluid state, description of the flow field, volume forces and surface forces, relative motion near a point, stress-strain relation, equations of fluid flows, surface tension, and a program for analysis of the governing equations. The dynamics of incompressible fluid flows is considered along with the dynamics of compressible fluid flows, the dynamics of viscous fluid flows, hydrodynamic stability, and dynamics of turbulence. Attention is given to the complex-variable method, three-dimensional irrotational flows, vortex flows, rotating flows, water waves, applications to aerodynamics, shock waves, potential flows, the hodograph method, flows at low and high Reynolds numbers, the Jeffrey-Hamel flow, and the capillary instability of a liquid jet.

Fluid Pocket Generation in Response to Heterogeneous Reactivity of a Rock Fracture Under Hydrothermal Conditions

NASA Astrophysics Data System (ADS)

Okamoto, A.; Tanaka, H.; Watanabe, N.; Saishu, H.; Tsuchiya, N.

2017-10-01

Fractures are the location of various water-rock interactions within the Earth's crust; however, the impact of the chemical heterogeneity of fractures on hydraulic properties is poorly understood. We conducted flow-through experiments on the dissolution of granite with a tensile fracture at 350°C and fluid pressure of 20 MPa with confining pressure of 40 MPa. The aperture structures were evaluated by X-ray computed tomography before and after the experiments. Under the experimental conditions, quartz grains dissolve rapidly to produce grain-scale pockets on the fracture surface, whereas altered feldspar grains act as asperities to sustain the open cavities. The fracture contained gouge with large surface area. The feedback between fluid flow and the rapid dissolution of gouge material produced large fluid pockets, whereas permeability did not always increase significantly. Such intense hydrological-chemical interactions could strongly influence the porosity-permeability relationship of fractured reservoirs in the crust.

CARBON AND SULFUR ACCUMULATION AND IRON MINERAL TRANSFORMATION IN PERMEABLE REACTIVE BARRIERS CONTAINING ZERO-VALENT IRON

EPA Science Inventory

Permeable reactive barrier technology is an in-situ approach for remediating groundwater contamination that combines subsurface fluid flow management with passive chemical treatment. Factors such as the buildup of mineral precipitates, buildup of microbial biomass (bio-fouling...

Simulations of reactive transport and precipitation with smoothed particle hydrodynamics

NASA Astrophysics Data System (ADS)

Tartakovsky, Alexandre M.; Meakin, Paul; Scheibe, Timothy D.; Eichler West, Rogene M.

2007-03-01

A numerical model based on smoothed particle hydrodynamics (SPH) was developed for reactive transport and mineral precipitation in fractured and porous materials. Because of its Lagrangian particle nature, SPH has several advantages for modeling Navier-Stokes flow and reactive transport including: (1) in a Lagrangian framework there is no non-linear term in the momentum conservation equation, so that accurate solutions can be obtained for momentum dominated flows and; (2) complicated physical and chemical processes such as surface growth due to precipitation/dissolution and chemical reactions are easy to implement. In addition, SPH simulations explicitly conserve mass and linear momentum. The SPH solution of the diffusion equation with fixed and moving reactive solid-fluid boundaries was compared with analytical solutions, Lattice Boltzmann [Q. Kang, D. Zhang, P. Lichtner, I. Tsimpanogiannis, Lattice Boltzmann model for crystal growth from supersaturated solution, Geophysical Research Letters, 31 (2004) L21604] simulations and diffusion limited aggregation (DLA) [P. Meakin, Fractals, scaling and far from equilibrium. Cambridge University Press, Cambridge, UK, 1998] model simulations. To illustrate the capabilities of the model, coupled three-dimensional flow, reactive transport and precipitation in a fracture aperture with a complex geometry were simulated.

Reactive Burn Model Calibration for PETN Using Ultra-High-Speed Phase Contrast Imaging

NASA Astrophysics Data System (ADS)

Johnson, Carl; Ramos, Kyle; Bolme, Cindy; Sanchez, Nathaniel; Barber, John; Montgomery, David

2017-06-01

A 1D reactive burn model (RBM) calibration for a plastic bonded high explosive (HE) requires run-to-detonation data. In PETN (pentaerythritol tetranitrate, 1.65 g/cc) the shock to detonation transition (SDT) is on the order of a few millimeters. This rapid SDT imposes experimental length scales that preclude application of traditional calibration methods such as embedded electromagnetic gauge methods (EEGM) which are very effective when used to study 10 - 20 mm thick HE specimens. In recent work at Argonne National Laboratory's Advanced Photon Source we have obtained run-to-detonation data in PETN using ultra-high-speed dynamic phase contrast imaging (PCI). A reactive burn model calibration valid for 1D shock waves is obtained using density profiles spanning the transition to detonation as opposed to particle velocity profiles from EEGM. Particle swarm optimization (PSO) methods were used to operate the LANL hydrocode FLAG iteratively to refine SURF RBM parameters until a suitable parameter set attained. These methods will be presented along with model validation simulations. The novel method described is generally applicable to `sensitive' energetic materials particularly those with areal densities amenable to radiography.

Method and apparatus for optical Doppler tomographic imaging of fluid flow velocity in highly scattering media

DOEpatents

Nelson, John Stuart; Milner, Thomas Edward; Chen, Zhongping

1999-01-01

Optical Doppler tomography permits imaging of fluid flow velocity in highly scattering media. The tomography system combines Doppler velocimetry with high spatial resolution of partially coherent optical interferometry to measure fluid flow velocity at discrete spatial locations. Noninvasive in vivo imaging of blood flow dynamics and tissue structures with high spatial resolutions of the order of 2 to 10 microns is achieved in biological systems. The backscattered interference signals derived from the interferometer may be analyzed either through power spectrum determination to obtain the position and velocity of each particle in the fluid flow sample at each pixel, or the interference spectral density may be analyzed at each frequency in the spectrum to obtain the positions and velocities of the particles in a cross-section to which the interference spectral density corresponds. The realized resolutions of optical Doppler tomography allows noninvasive in vivo imaging of both blood microcirculation and tissue structure surrounding the vessel which has significance for biomedical research and clinical applications.

EVALUATION OF FGD DRY INJECTION SORBENTS AND ADDITIVES - VOLUME 1 - DEVELOPMENT OF HIGH REACTIVITY SORBENTS

EPA Science Inventory

The report discusses recent work addressing lime enhancement by slurrying with siliceous materials and testing in a laboratory packed-bed reactor, as part of EPA's efforts to develop low cost, retrofit flue gas cleaning technology, including the development of highly reactive sor...

Fluid Film Bearing Code Development

NASA Technical Reports Server (NTRS)

1995-01-01

The next generation of rocket engine turbopumps is being developed by industry through Government-directed contracts. These turbopumps will use fluid film bearings because they eliminate the life and shaft-speed limitations of rolling-element bearings, increase turbopump design flexibility, and reduce the need for turbopump overhauls and maintenance. The design of the fluid film bearings for these turbopumps, however, requires sophisticated analysis tools to model the complex physical behavior characteristic of fluid film bearings operating at high speeds with low viscosity fluids. State-of-the-art analysis and design tools are being developed at the Texas A&M University under a grant guided by the NASA Lewis Research Center. The latest version of the code, HYDROFLEXT, is a thermohydrodynamic bulk flow analysis with fluid compressibility, full inertia, and fully developed turbulence models. It can predict the static and dynamic force response of rigid and flexible pad hydrodynamic bearings and of rigid and tilting pad hydrostatic bearings. The Texas A&M code is a comprehensive analysis tool, incorporating key fluid phenomenon pertinent to bearings that operate at high speeds with low-viscosity fluids typical of those used in rocket engine turbopumps. Specifically, the energy equation was implemented into the code to enable fluid properties to vary with temperature and pressure. This is particularly important for cryogenic fluids because their properties are sensitive to temperature as well as pressure. As shown in the figure, predicted bearing mass flow rates vary significantly depending on the fluid model used. Because cryogens are semicompressible fluids and the bearing dynamic characteristics are highly sensitive to fluid compressibility, fluid compressibility effects are also modeled. The code contains fluid properties for liquid hydrogen, liquid oxygen, and liquid nitrogen as well as for water and air. Other fluids can be handled by the code provided that the

Methods for compressible fluid simulation on GPUs using high-order finite differences

NASA Astrophysics Data System (ADS)

Pekkilä, Johannes; Väisälä, Miikka S.; Käpylä, Maarit J.; Käpylä, Petri J.; Anjum, Omer

2017-08-01

We focus on implementing and optimizing a sixth-order finite-difference solver for simulating compressible fluids on a GPU using third-order Runge-Kutta integration. Since graphics processing units perform well in data-parallel tasks, this makes them an attractive platform for fluid simulation. However, high-order stencil computation is memory-intensive with respect to both main memory and the caches of the GPU. We present two approaches for simulating compressible fluids using 55-point and 19-point stencils. We seek to reduce the requirements for memory bandwidth and cache size in our methods by using cache blocking and decomposing a latency-bound kernel into several bandwidth-bound kernels. Our fastest implementation is bandwidth-bound and integrates 343 million grid points per second on a Tesla K40t GPU, achieving a 3 . 6 × speedup over a comparable hydrodynamics solver benchmarked on two Intel Xeon E5-2690v3 processors. Our alternative GPU implementation is latency-bound and achieves the rate of 168 million updates per second.

Mice selected for high versus low stress reactivity: a new animal model for affective disorders.

PubMed

Touma, Chadi; Bunck, Mirjam; Glasl, Lisa; Nussbaumer, Markus; Palme, Rupert; Stein, Hendrik; Wolferstätter, Michael; Zeh, Ramona; Zimbelmann, Marina; Holsboer, Florian; Landgraf, Rainer

2008-07-01

Affective disorders such as major depression are among the most prevalent and costly diseases of the central nervous system, but the underlying mechanisms are still poorly understood. In recent years, it has become evident that alterations of the stress hormone system, in particular dysfunctions (hyper- or hypo-activity) of the hypothalamic-pituitary-adrenal (HPA) axis, play a prominent role in the development of major depressive disorders. Therefore, we aimed to generate a new animal model comprising these neuroendocrine core symptoms in order to unravel parameters underlying increased or decreased stress reactivity. Starting from a population of outbred mice (parental generation: 100 males and 100 females of the CD-1 strain), two breeding lines were established according to the outcome of a 'stress reactivity test' (SRT), consisting of a 15-min restraint period and tail blood samplings immediately before and after exposure to the stressor. Mice showing a very high or a very low secretion of corticosterone in the SRT, i.e. animals expressing a hyper- or a hypo-reactivity of the HPA axis, were selected for the 'high reactivity' (HR) and the 'low reactivity' (LR) breeding line, respectively. Additionally, a third breeding line was established consisting of animals with an 'intermediate reactivity' (IR) in the SRT. Already in the first generation, i.e. animals derived from breeding pairs selected from the parental generation, significant differences in the reactivity of the HPA axis between HR, IR, and LR mice were observed. Moreover, these differences were found across all subsequent generations and could be increased by selective breeding, which indicates a genetic basis of the respective phenotype. Repeated testing of individuals in the SRT furthermore proved that the observed differences in stress responsiveness are present already early in life and can be regarded as a robust genetic predisposition. Tests investigating the animal's emotionality including anxiety

LONG-TERM PERFORMANCE OF PERMEABLE REACTIVE BARRIERS: AN UPDATE ON A U.S. MULTI-AGENCY INITIATIVE

EPA Science Inventory

Permeable reactive barriers (PRB's) are an emerging, alternative in-situ approach for remediating contaminated groundwater that combine subsurface fluid flow management with a passive chemical treatment zone. PRB's are a potentially more cost effective treatment option at seve...

Highly resolved fluid flows: "liquid plasmas" at the kinetic level.

PubMed

Morfill, Gregor E; Rubin-Zuzic, Milenko; Rothermel, Hermann; Ivlev, Alexei V; Klumov, Boris A; Thomas, Hubertus M; Konopka, Uwe; Steinberg, Victor

2004-04-30

Fluid flow around an obstacle was observed at the kinetic (individual particle) level using "complex (dusty) plasmas" in their liquid state. These "liquid plasmas" have bulk properties similar to water (e.g., viscosity), and a comparison in terms of similarity parameters suggests that they can provide a unique tool to model classical fluids. This allows us to study "nanofluidics" at the most elementary-the particle-level, including the transition from fluid behavior to purely kinetic transport. In this (first) experimental investigation we describe the kinetic flow topology, discuss our observations in terms of fluid theories, and follow this up with numerical simulations.

Fluid-rock interaction at the northern Hunter Mountain contact aureole, CA, USA

NASA Astrophysics Data System (ADS)

Skora, S.; Baumgartner, L.

2003-04-01

One of the world largest wollastonite deposits is located at the northern end of the Hunter Mountain Batholith, Death Valley National Park (CA, USA). The exposed Palaeozoic continental shelf sediments consist of sandy dolomites and limestones, often interbedded with chert nodules and quartzitic layers. The wollastonite was formed in the quartz-rich zones within the Mississippian Tin Mountain Limestone and the Devonian Lost Burro Formation. The sediment sequence was folded and thrusted towards the SE during the Permian/Triassic Sonoma orogeny. The folds were partly reactivated and rotated during the intrusion. A large, km-scale, anticline/syncline pair was folded and rotated from its the regional N-S trend into an E-W trend during intrusion of the Hunter Mountain Batholith and its satellite. Contact metamorphism resulted in the formation of tremolite, forsterite, and periclase in the siliceous dolomites. Tremolite, diopside and wollastonite were produced in quartz-dolomite-bearing limestones. Evidence for fluid flow is found in the intrusion and the host rocks. The periclase zone in dolomites next to the intrusion documents infiltration of a water-rich, probably magmatic, fluid. The X{CO_2} content was < 0.07 at temperatures of 640 - 700^oC. Furthermore, bodies of wollastonite ore occur well within the tremolite zone, in the northern part of a anticline. This demonstrates channelized infiltration of water-rich fluids (X{CO_2} < 0.03) and the capture of fluids in fold hinges. δD-values of 60-90 ppm (SMOW) of tremolites are consistent with the presence of magmatic water. Sets of irregularly spaced (0,2 - 2m), parallel, sub-horizontal fractures next to the wollastonite ore document fluid circulation in the cooling intrusion. Alteration zones (2-5cm) surround these fractures. Here, the kfs+cpx+pl+qtz+bt+hbl+mag igneous assemblage is changed to scp+hbl+cal+ab+ti±ep. Ti-rich, oscillatory zoned garnets partially fill these fractures. This relatively high temperature

High Pressure, Transport Properties of Fluids: Theory and Data from Levitated Fluid-Drops at Combustion-Relevant Temperatures

NASA Technical Reports Server (NTRS)

Bellan, J.; Ohaska, K.

2001-01-01

The objective of this investigation is to derive a set of consistent mixing rules for calculating diffusivities and thermal diffusion factors over a thermodynamic regime encompassing the subcritical and supercritical ranges. These should serve for modeling purposes, and therefore for accurate simulations of high pressure phenomena such as fluid disintegration, turbulent flows and sprays. A particular consequence of this work will be the determination of effective Lewis numbers for supercritical conditions, thus enabling the examination of the relative importance of heat and mass transfer at supercritical pressures.

Fluid Dynamics of Clap-and-Fling with Highly Flexible Wings inspired by the Locomotion of Sea Butterflies

NASA Astrophysics Data System (ADS)

Zhou, Zhuoyu; Shoele, Kourosh; Adhikari, Deepak; Yen, Jeannette; Webster, Donald; Mittal, Rajat; Johns Hopkins University Team; Georgia Institute of Technology Team

2015-11-01

This study is motivated by the locomotion of sea butterflies (L. Helicina) which propel themselves in the water column using highly flexible wing-like parapodia. These animals execute a complex clap-and-fling with their highly flexible wings that is different from that of insects, and the fluid dynamics of which is not well understood. We use two models to study the fluid dyamics of these wings. In the first, we use prescribed wing kinematics that serve as a model of those observed for these animals. The second model is a fluid-structure interaction model where wing-like parapodia are modeled as flexible but inextensible membranes. The membrane properties, such as bending and stretching stiffness are modified such that the corresponding motion qualitatively matches the kinematics of L. helicina. Both models are used to examine the fluid dynamics of the clap-and-fling and its effectiveness in generating lift for these animals. Acknowledgement - research is supported by a grant from NSF.

In utero cortisol and testosterone exposure and fear reactivity in infancy.

PubMed

Bergman, Kristin; Glover, Vivette; Sarkar, Pampa; Abbott, Dave H; O'Connor, Thomas G

2010-03-01

Fetal programming is emerging as a major conceptual model for understanding developmental origins of health and disease, including behavioral outcomes. As part of a larger study of prenatal stress and child development, we examined the association between prenatal hormone exposure and fear reactivity, a temperament dimension that is a predictor of long-term behavioral adjustment. Amniotic fluid was collected from a sample of women undergoing clinically indicated amniocentesis for later analysis of cortisol and testosterone. Children with normal birth outcomes were recalled for follow-up assessment at 17 months, at which time we administered an observational assessment of temperament (lab-TAB; n=108). Information on pregnancy and obstetric outcome was included as covariates. Results indicated that there was a significant association between prenatal testosterone and observed fear reactivity in boys (r(53)=0.34, p=0.01); no significant effect was found in girls (r(54)=-0.07, ns); the effect remained when obstetric, psychosocial, and parental anxiety were controlled for. There was not a significant association between fetal cortisol exposure and fear reactivity. The prediction from in utero testosterone exposure to fear reactivity in boys extends prior research on prenatal testosterone and may represent an association with a general predisposition to greater arousal and reactivity. Copyright 2010 Elsevier Inc. All rights reserved.

In utero cortisol and testosterone exposure and fear reactivity in infancy

PubMed Central

Bergman, Kristin; Glover, Vivette; Sarkar, Pampa; Abbott, Dave; O'Connor, Thomas G

2010-01-01

Fetal programming is emerging as a major conceptual model for understanding developmental origins of health and disease, including behavioral outcomes. As part of a larger study of prenatal stress and child development, we examined the association between prenatal hormone exposure and fear reactivity, a temperament dimension that is a predictor of long-term behavioral adjustment. Amniotic fluid was collected from a sample of women undergoing clinically indicated amniocentesis for later analysis of cortisol and testosterone. Children with normal birth outcomes were recalled for follow-up assessment at 17 months, at which time we administered an observational assessment of temperament (lab-TAB; n=108). Information on pregnancy and obstetric outcome was included as covariates. Results indicated that there was a significant association between prenatal testosterone and observed fear reactivity in boys (r(53)=0.34, p=0.01); no significant effect was found in girls (r(54)=-.07, ns); the effect remained when obstetric, psychosocial, and parental anxiety were controlled for. There was not a significant association between fetal cortisol exposure and fear reactivity. The prediction from in utero testosterone exposure to fear reactivity in boys extends prior research on prenatal testosterone, and may represent an association with a general predisposition to greater arousal and reactivity. PMID:20060000

When sticky fluids don't stick: yield-stress fluid drops on heated surfaces

NASA Astrophysics Data System (ADS)

Blackwell, Brendan; Wu, Alex; Ewoldt, Randy

2016-11-01

Yield-stress fluids, including gels and pastes, are effectively fluid at high stress and solid at low stress. In liquid-solid impacts, these fluids can stick and accumulate where they impact; this sticky behavior motivates several applications of these rheologically-complex materials. Here we describe experiments with aqueous yield stress fluids that are more 'sticky' than water at room temperature (e.g. supporting larger coating thicknesses), but are less 'sticky' at higher temperatures. Specifically, we study the conditions for aqueous yield stress fluids to bounce and slide on heated surfaces when water sticks. Here we present high-speed imaging and color interferometry to observe the thickness of the vapor layer between the drop and the surface during both stick and non-stick events. We use these data to gain insight into the physics behind the phenomenon of the yield-stress fluids bouncing and sliding, rather than sticking, on hot surfaces.

Final Report: Ionization chemistry of high temperature molecular fluids

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

Fried, L E

2007-02-26

With the advent of coupled chemical/hydrodynamic reactive flow models for high explosives, understanding detonation chemistry is of increasing importance to DNT. The accuracy of first principles detonation codes, such as CHEETAH, are dependent on an accurate representation of the species present under detonation conditions. Ionic species and non-molecular phases are not currently included coupled chemistry/hydrodynamic simulations. This LDRD will determine the prevalence of such species during high explosive detonations, by carrying out experimental and computational investigation of common detonation products under extreme conditions. We are studying the phase diagram of detonation products such as H{sub 2}O, or NH{sub 3} andmore » mixtures under conditions of extreme pressure (P > 1 GPa) and temperature (T > 1000K). Under these conditions, the neutral molecular form of matter transforms to a phase dominated by ions. The phase boundaries of such a region are unknown.« less

Falling, flapping, flying, swimming,...: High-Re fluid-solid interactions with vortex shedding

NASA Astrophysics Data System (ADS)

Michelin, Sebastien Honore Roland

The coupling between the motion of a solid body and the dynamics of the surrounding flow is essential to the understanding of a large number of engineering and physical problems, from the stability of a slender structure exposed to the wind to the locomotion of insects, birds and fishes. Because of the strong coupling on a moving boundary of the equations for the solid and fluid, the simulation of such problems is computationally challenging and expensive. This justifies the development of simplified models for the fluid-solid interactions to study their physical properties and behavior. This dissertation proposes a reduced-order model for the interaction of a sharp-edged solid body with a strongly unsteady high Reynolds number flow. In such a case, viscous forces in the fluid are often negligible compared to the fluid inertia or the pressure forces, and the thin boundary layers separate from the solid at the edges, leading to the shedding of large and persistent vortices in the solid's wake. A general two-dimensional framework is presented based on complex potential flow theory. The formation of the solid's vortical wake is accounted for by the shedding of point vortices with unsteady intensity from the solid's sharp edges, and the fluid-solid problem is reformulated exclusively as a solid-vortex interaction problem. In the case of a rigid solid body, the coupled problem is shown to reduce to a set of non-linear ordinary differential equations. This model is used to study the effect of vortex shedding on the stability of falling objects. The solid-vortex model is then generalized to study the fluttering instability and non-linear flapping dynamics of flexible plates or flags. The uttering instability and resulting flapping motion result from the competing effects of the fluid forcing and of the solid's flexural rigidity and inertia. Finally, the solid-vortex model is applied to the study of the fundamental effect of bending rigidity on the flapping performance of

Geochemistry of High Temperature Vent Fluids in Yellowstone Lake: Dissolved Carbon and Sulfur Concentrations and Isotopic Data

NASA Astrophysics Data System (ADS)

Cino, C.; Seyfried, W. E., Jr.; Tan, C.; Fu, Q.

2017-12-01

Yellowstone National Park is a dynamic environment home to an array of geysers, hot springs, and hydrothermal vents fueled by the underlying continental magmatic intrusion. Yellowstone Lake vent fluids accounts for approximately 10% of the total geothermal flux for all of Yellowstone National Park. Though studying this remote hydrothermal system poses severe challenges, it provides an excellent natural laboratory to research hydrothermal fluids that undergo higher pressure and temperature conditions in an environment largely shielded from atmospheric oxygen. The location of these vents also provides chemistry that is characteristic of fluids deeper in the Yellowstone hydrothermal system. In August 2016, hydrothermal fluids were collected from the Stevenson Island vents in collaboration with the Hydrothermal Dynamics of Yellowstone Lake (HD-YLAKE) project using novel sampling techniques and monitoring instrumentation. The newly built ROV Yogi was deployed to reach the vents in-situ with temperatures in excess of 151oC at 100-120 m depth, equipped with a 12-cylinder isobaric sampler to collect the hydrothermal fluids. Results from geochemical analyses indicate the fluids are rich in gases such as CO2, CH4, and H2S, with sample concentrations of approximately 12 mM, 161 μm, and 2.1 mM respectively. However, lake water mixing with the hydrothermal endmember fluid likely diluted these concentrations in the collected samples. Isotopic analyses indicate CO2 has a δ13C of -6 indicating magmatic origins, however the CH4 resulted in a δ13C of -65 which is in the biological range. This biogenic signature is likely due to the pyrolysis of immature organic matter in the lake bottom sediment, since the high temperatures measured for the fluids would not allow the presence of methanogens. H2S concentrations have not been previously measured for the hydrothermal fluids in Yellowstone Lake, and our vent fluid samples indicate significantly higher H2S concentrations than reported

Method for generating a highly reactive plasma for exhaust gas after treatment and enhanced catalyst reactivity

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

Whealton, John H.; Hanson, Gregory R.; Storey, John M.

This patent application describes a method and apparatus of exhaust gas remediation that enhance the reactivity of the material catalysts found within catalytic converters of cars, trucks, and power stations.

Management of children undergoing cardiac transplantation with high Panel Reactive Antibodies.

PubMed

Asante-Korang, Alfred; Jacobs, Jeffrey P; Ringewald, Jeremy; Carapellucci, Jennifer; Rosenberg, Kristin; McKenna, Daniel; McCormack, Jorge; Wilmot, Ivan; Gjeldum, Abigail; Lopez-Cepero, Mayra; Sleasman, John

2011-12-01

Highly sensitised children in need of cardiac transplantation have overall poor outcomes because of increased risk for dysfunction of the cardiac allograft, acute cellular and antibody-mediated rejection, and vasculopathy of the cardiac allograft. Cardiopulmonary bypass and the frequent use of blood products in the operating room and cardiac intensive care unit, as well as the frequent use of homografts, have predisposed potential recipients of transplants to allosensitisation. The expansion in the use of ventricular assist devices and extracorporeal membrane oxygenation has also contributed to increasing rates of allosensitisation in candidates for cardiac transplantation. Antibodies to Human Leukocyte Antigen can be detected before transplantation using several different techniques, the most common being the "complement-dependent lymphocytotoxicity assays". "Solid-phase assays", particularly the "Luminex® single antigen bead method", offer improved specificity and more detailed information regarding specificities of antibodies, leading to improved matching of donors with recipients. Allosensitisation prolongs the time on the waiting list for potential recipients of transplantation and increases the risk of complications and death after transplantation. Aggressive reduction of antibodies to Human Leukocyte Antigen in these high-risk patients is therefore of vital importance for long-term survival of the patient and cardiac allograft. Strategies to decrease Panel Reactive Antibody or percent reactive antibody before transplantation include plasmapheresis, intravenous administration of immunoglobulin, and specific treatment to reduce B-cells, particularly Rituximab. These strategies have resulted in varying degrees of success. Antibody-mediated rejection and cardiac allograft vasculopathy are two of the most important complications of transplantation in patients with high Panel Reactive Antibody. The treatment of antibody-mediated rejection in recipients of cardiac

The Effects of High Level Magnesium Dialysis/Substitution Fluid on Magnesium Homeostasis under Regional Citrate Anticoagulation in Critically Ill

PubMed Central

Los, Ferdinand; Brodska, Helena

2016-01-01

Background The requirements for magnesium (Mg) supplementation increase under regional citrate anticoagulation (RCA) because citrate acts by chelation of bivalent cations within the blood circuit. The level of magnesium in commercially available fluids for continuous renal replacement therapy (CRRT) may not be sufficient to prevent hypomagnesemia. Methods Patients (n = 45) on CRRT (2,000 ml/h, blood flow (Qb) 100 ml/min) with RCA modality (4% trisodium citrate) using calcium free fluid with 0.75 mmol/l of Mg with additional magnesium substitution were observed after switch to the calcium-free fluid with magnesium concentration of 1.50 mmol/l (n = 42) and no extra magnesium replenishment. All patients had renal indications for CRRT, were treated with the same devices, filters and the same postfilter ionized calcium endpoint (<0.4 mmol/l) of prefilter citrate dosage. Under the high level Mg fluid the Qb, dosages of citrate and CRRT were consequently escalated in 9h steps to test various settings. Results Median balance of Mg was -0.91 (-1.18 to -0.53) mmol/h with Mg 0.75 mmol/l and 0.2 (0.06–0.35) mmol/h when fluid with Mg 1.50 mmol/l was used. It was close to zero (0.02 (-0.12–0.18) mmol/h) with higher blood flow and dosage of citrate, increased again to 0.15 (-0.11–0.25) mmol/h with 3,000 ml/h of high magnesium containing fluid (p<0.001). The arterial levels of Mg were mildly increased after the change for high level magnesium containing fluid (p<0.01). Conclusions Compared to ordinary dialysis fluid the mildly hypermagnesemic fluid provided even balances and adequate levels within ordinary configurations of CRRT with RCA and without a need for extra magnesium replenishment. Trial Registration ClinicalTrials.gov Identifier: NCT01361581 PMID:27391902

Plasma reactivity in high-power impulse magnetron sputtering through oxygen kinetics

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

Vitelaru, Catalin; National Institute for Optoelectronics, Magurele-Bucharest, RO 077125; Lundin, Daniel

2013-09-02

The atomic oxygen metastable dynamics in a Reactive High-Power Impulse Magnetron Sputtering (R-HiPIMS) discharge has been characterized using time-resolved diode laser absorption in an Ar/O{sub 2} gas mixture with a Ti target. Two plasma regions are identified: the ionization region (IR) close to the target and further out the diffusion region (DR), separated by a transition region. The μs temporal resolution allows identifying the main atomic oxygen production and destruction routes, which are found to be very different during the pulse as compared to the afterglow as deduced from their evolution in space and time.

Cavitand-Based Polyphenols as Highly Reactive Organocatalysts for the Coupling of Carbon Dioxide and Oxiranes.

PubMed

Martínez-Rodríguez, Luis; Otalora Garmilla, Javier; Kleij, Arjan W

2016-04-07

A variety of cavitand-based polyphenols was prepared from cheap and accessible aldehyde and resorcinol/pyrogallol reagents to give the respective resorcin[4]- or pyrogallol[4]arenes. The preorganization of the phenolic units allows intra- and intermolecular hydrogen bond (HB) networks that affect both the reactivity and stability of these HB-donor catalysts. Unexpectedly, we found that the resorcin[4]arenes show cooperative catalysis behavior compared to the parent resorcinol in the catalytic coupling of epoxides and CO2 with a significantly higher turnover. At elevated reaction temperatures, the resorcin[4]arene-based catalyst 3 d displays the best catalytic performance with very high turnover numbers and frequencies, combining increased reactivity and stability compared to pyrogallol, and an ample substrate scope. This type of polyphenol structure thus illustrates the importance of a new, highly competitive organocatalyst design to devise sustainable CO2 conversion processes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Pressure Combustion Experimental Facility(HPCEF) for Studies on Combustion in Reactive Flows

DTIC Science & Technology

2017-12-13

SECURITY CLASSIFICATION OF: 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 13. SUPPLEMENTARY NOTES 12. DISTRIBUTION AVAILIBILITY STATEMENT 6...Report: High Pressure Combustion Experimental Facility (HPCEF) for Studies on Combustion in Reactive Flows The views, opinions and/or findings... contained in this report are those of the author(s) and should not contrued as an official Department of the Army position, policy or decision, unless so

Oral Fluids as a Live-Animal Sample Source for Evaluating Cross-Reactivity and Cross-Protection following Intranasal Influenza A Virus Vaccination in Pigs

PubMed Central

Hughes, Holly R.; Vincent, Amy L.; Brockmeier, Susan L.; Gauger, Phillip C.; Pena, Lindomar; Santos, Jefferson; Braucher, Douglas R.

2015-01-01

In North American swine, there are numerous antigenically distinct H1 influenza A virus (IAV) variants currently circulating, making vaccine development difficult due to the inability to formulate a vaccine that provides broad cross-protection. Experimentally, live-attenuated influenza virus (LAIV) vaccines demonstrate increased cross-protection compared to inactivated vaccines. However, there is no standardized assay to predict cross-protection following LAIV vaccination. Hemagglutination-inhibiting (HI) antibody in serum is the gold standard correlate of protection following IAV vaccination. LAIV vaccination does not induce a robust serum HI antibody titer; however, a local mucosal antibody response is elicited. Thus, a live-animal sample source that could be used to evaluate LAIV immunogenicity and cross-protection is needed. Here, we evaluated the use of oral fluids (OF) and nasal wash (NW) collected after IAV inoculation as a live-animal sample source in an enzyme-linked immunosorbent assay (ELISA) to predict cross-protection in comparison to traditional serology. Both live-virus exposure and LAIV vaccination provided heterologous protection, though protection was greatest against more closely phylogenetically related viruses. IAV-specific IgA was detected in NW and OF samples and was cross-reactive to representative IAV from each H1 cluster. Endpoint titers of cross-reactive IgA in OF from pigs exposed to live virus was associated with heterologous protection. While LAIV vaccination provided significant protection, LAIV immunogenicity was reduced compared to live-virus exposure. These data suggest that OF from pigs inoculated with wild-type IAV, with surface genes that match the LAIV seed strain, could be used in an ELISA to assess cross-protection and the antigenic relatedness of circulating and emerging IAV in swine. PMID:26291090

A THC Simulator for Modeling Fluid-Rock Interactions

NASA Astrophysics Data System (ADS)

Hamidi, Sahar; Galvan, Boris; Heinze, Thomas; Miller, Stephen

2014-05-01

Fluid-rock interactions play an essential role in many earth processes, from a likely influence on earthquake nucleation and aftershocks, to enhanced geothermal system, carbon capture and storage (CCS), and underground nuclear waste repositories. In THC models, two-way interactions between different processes (thermal, hydraulic and chemical) are present. Fluid flow influences the permeability of the rock especially if chemical reactions are taken into account. On one hand solute concentration influences fluid properties while, on the other hand, heat can affect further chemical reactions. Estimating heat production from a naturally fractured geothermal systems remains a complex problem. Previous works are typically based on a local thermal equilibrium assumption and rarely consider the salinity. The dissolved salt in fluid affects the hydro- and thermodynamical behavior of the system by changing the hydraulic properties of the circulating fluid. Coupled thermal-hydraulic-chemical models (THC) are important for investigating these processes, but what is needed is a coupling to mechanics to result in THMC models. Although similar models currently exist (e.g. PFLOTRAN), our objective here is to develop algorithms for implementation using the Graphics Processing Unit (GPU) computer architecture to be run on GPU clusters. To that aim, we present a two-dimensional numerical simulation of a fully coupled non-isothermal non-reactive solute flow. The thermal part of the simulation models heat transfer processes for either local thermal equilibrium or nonequilibrium cases, and coupled to a non-reactive mass transfer described by a non-linear diffusion/dispersion model. The flow process of the model includes a non-linear Darcian flow for either saturated or unsaturated scenarios. For the unsaturated case, we use the Richards' approximation for a mixture of liquid and gas phases. Relative permeability and capillary pressure are determined by the van Genuchten relations

Diffusion-controlled reactions: hydrodynamic interaction between charged, uniformly reactive spherical reactants.

PubMed

Allison, Stuart

2006-12-28

In this work, different models of hydrodynamic interaction (HI) are examined in the diffusion-controlled reaction between uniformly reactive charged spherical particles. In addition to Oseen "stick" and "slip" models of HI, one is considered that accounts for the disturbance of fluid flow by the ions around one reactive partner as they interact with a neighboring reactive species. This interaction is closely related to the "electrophoretic effect" in electrokinetics and can be described by a fairly simple electrophoretic, or E-tensor. These models are applied to the electron-transfer quenching reaction of Ru(bpy)3(2+) and methyl viologen (MV2+) over a wide range of NaCl concentrations (Chiorboli, C. et al., J. Phys. Chem. 1988, 92, 156). The back reaction is also considered. From a comparison of the salt dependence of the model and experimental rates, it is concluded that the "E-tensor" model works best and ignoring HI altogether works worst. The Oseen "stick" and "slip" models fall between these.

Origin of high-grade gold ore, source of ore fluid components, and genesis of the Meikle and neighboring Carlin-type deposits, Northern Carlin Trend, Nevada

USGS Publications Warehouse

Emsbo, P.; Hofstra, A.H.; Lauha, E.A.; Griffin, G.L.; Hutchinson, R.W.

2003-01-01

The Meikle mine exploits one of the world's highest grade Carlin-type gold deposits with reserves of ca. 220 t gold at an average grade of 24.7 g/t. Locally, gold grades exceed 400 g/t. Several geologic events converged at Meikle to create these spectacular gold grades. Prior to mineralization, a Devonian hydrothermal system altered the Bootstrap limestone to Fe-rich dolomite. Subsequently the rocks were brecciated by faulting and Late Jurassic intrusive activity. The resulting permeability focused flow of late Eocene Carlin-type ore fluids and allowed them to react with the Fe-rich dolomite. Fluid inclusion data and mineral assemblages indicate that these fluids were hot (ca. 220??C),of moderate salinity (400 g/t. Petrographic observations, geochemical data, and stable isotope results from the Meikle mine and other deposits at the Goldstrike mine place important constraints on genetic models for Meikle and other Carlin-type gold deposits on the northern Carlin trend. The ore fluids were meteoric water (??D = -135???, ??18O = -5???) that interacted with sedimentary rocks at a water/rock ratio of ca. 1 and temperatures of ca. 220??C. The absence of significant silicification suggests that there was little cooling of the ore fluids during mineralization. These two observations strongly suggest that ore fluids were not derived from deep sources but instead flowed parallel to isotherms. The gold was transported by H2S (??34S = 9???), which was derived from Paleozoic sedimentary rocks. The presence of auriferous sedimentary exhalative mineralization in the local stratigraphic sequence raises the possibility that preexisting concentrations of gold contributed to the Carlin-type deposits. Taken together our observations suggest that meteoric water evolved to become an ore fluid by shallow circulation through previously gold- and sulfur-enriched rocks. Carlin-type gold deposits formed where these fluids encountered permeable, reactive Fe-rich rocks.

Computational Fluid Dynamics Analysis of High Injection Pressure Blended Biodiesel

NASA Astrophysics Data System (ADS)

Khalid, Amir; Jaat, Norrizam; Faisal Hushim, Mohd; Manshoor, Bukhari; Zaman, Izzuddin; Sapit, Azwan; Razali, Azahari

2017-08-01

Biodiesel have great potential for substitution with petrol fuel for the purpose of achieving clean energy production and emission reduction. Among the methods that can control the combustion properties, controlling of the fuel injection conditions is one of the successful methods. The purpose of this study is to investigate the effect of high injection pressure of biodiesel blends on spray characteristics using Computational Fluid Dynamics (CFD). Injection pressure was observed at 220 MPa, 250 MPa and 280 MPa. The ambient temperature was kept held at 1050 K and ambient pressure 8 MPa in order to simulate the effect of boost pressure or turbo charger during combustion process. Computational Fluid Dynamics were used to investigate the spray characteristics of biodiesel blends such as spray penetration length, spray angle and mixture formation of fuel-air mixing. The results shows that increases of injection pressure, wider spray angle is produced by biodiesel blends and diesel fuel. The injection pressure strongly affects the mixture formation, characteristics of fuel spray, longer spray penetration length thus promotes the fuel and air mixing.

High-scale expansion of melanoma-reactive TIL by a polyclonal stimulus: predictability and relation with disease advancement.

PubMed

Pandolfino, M C; Labarrière, N; Tessier, M H; Cassidanius, A; Bercegeay, S; Lemarre, P; Dehaut, F; Dréno, B; Jotereau, F

2001-05-01

The rationale of treating melanoma patients by infusion with tumor-infiltrating leukocytes (TIL) is to perform an adoptive therapy through injection of tumor-specific T cells. Nonetheless, methods currently used for ex vivo TIL expansion have not been evaluated for their efficacy to expand TAA-specific T cells. We have addressed this question here, using a culture method in which high TIL growth was induced by a polyclonal T cell stimulus. Intracellular cytokine assays were performed to measure the proportion of T cells responding to autologous tumor cells among the lymphocytes from lymph node biopsies (TIL) of 26 patients with stage III melanoma. The data show that TIL from 18 of these patients contained detectable amounts of tumor-specific T cells before expansion. Although they decreased somewhat in percent abundance during expansion, they were still present afterwards, ranging from 0.3 to 13.8%. Since a median number of 1.7 x 10(10) TIL was obtained from these patients (starting from 3.6 x 10(6) TIL), a total amount of tumor-reactive cytokine-secreting TIL of between 2.8 x 10(6) and 1.12 x 10(9) was obtained in each case from 18 patients. The TIL populations from 8 patients did not contain tumor-reactive T cells: neither before expansion, nor after expansion. Lack of tumor-reactive TIL only occurs for patients bearing several tumor-invaded lymph nodes (40%), but not for those having a single invaded lymph node. Therefore, high numbers of tumor-reactive T cells can be produced, through a polyclonal TIL stimulation, from most early stage III melanoma patients but from only about half of the patients with a more disseminated disease. For this last group, the possibility of getting tumor-reactive TIL can be predicted by checking the presence of these cells before expansion.

Effect of ticagrelor with clopidogrel on high on-treatment platelet reactivity in acute stroke or transient ischemic attack (PRINCE) trial: Rationale and design.

PubMed

Wang, Yilong; Lin, Yi; Meng, Xia; Chen, Weiqi; Chen, Guohua; Wang, Zhimin; Wu, Jialing; Wang, Dali; Li, Jianhua; Cao, Yibin; Xu, Yuming; Zhang, Guohua; Li, Xiaobo; Pan, Yuesong; Li, Hao; Liu, Liping; Zhao, Xingquan; Wang, Yongjun

2017-04-01

Rationale and aim Little is known about the safety and efficacy of the combination of ticagrelor and aspirin in acute ischemic stroke. This study aimed to evaluate whether the combination of ticagrelor and aspirin was superior to that of clopidogrel and aspirin in reducing the 90-day high on-treatment platelet reactivity for acute minor stroke or transient ischemic attack, especially for carriers of cytochrome P450 2C19 loss-of-function allele. Sample size and design This study was designed as a prospective, multicenter, randomized, open-label, active-controlled, and blind-endpoint, phase II b trial. The required sample size was 952 patients. It was registered with ClinicalTrials.gov (NCT02506140). Study outcomes The primary outcome was the proportion of patients with high on-treatment platelet reactivity at 90 days. High on-treatment platelet reactivity is defined as the P2Y12 reaction unit >208 measured using the VerifyNow P2Y12 assay. Conclusion The Platelet Reactivity in Acute Non-disabling Cerebrovascular Events study explored whether ticagrelor combined with aspirin could reduce further the proportion of patients with high on-treatment platelet reactivity at 90 days after acute minor stroke or transient ischemic attack compared with clopidogrel and aspirin.

Enhanced reaction kinetics and reactive mixing scale dynamics in mixing fronts under shear flow for arbitrary Damköhler numbers

NASA Astrophysics Data System (ADS)

Bandopadhyay, Aditya; Le Borgne, Tanguy; Méheust, Yves; Dentz, Marco

2017-02-01

Mixing fronts, where fluids of different chemical compositions mix with each other, are known to represent hotspots of chemical reaction in hydrological systems. These fronts are typically subjected to velocity gradients, ranging from the pore scale due to no slip boundary conditions at fluid solid interfaces, to the catchment scale due to permeability variations and complex geometry of the Darcy velocity streamlines. A common trait of these processes is that the mixing interface is strained by shear. Depending on the Péclet number Pe , which represents the ratio of the characteristic diffusion time to the characteristic shear time, and the Damköhler number Da , which represents the ratio of the characteristic diffusion time to the characteristic reaction time, the local reaction rates can be strongly impacted by the dynamics of the mixing interface. So far, this impact has been characterized mostly either in kinetics-limited or in mixing-limited conditions, that is, for either low or high Da. Here the coupling of shear flow and chemical reactivity is investigated for arbitrary Damköhler numbers, for a bimolecular reaction and an initial interface with separated reactants. Approximate analytical expressions for the global production rate and reactive mixing scale are derived based on a reactive lamella approach that allows for a general coupling between stretching enhanced mixing and chemical reactions. While for Pe < Da , reaction kinetics and stretching effects are decoupled, a scenario which we name "weak stretching", for Pe > Da , we uncover a "strong stretching" scenario where new scaling laws emerge from the interplay between reaction kinetics, diffusion, and stretching. The analytical results are validated against numerical simulations. These findings shed light on the effect of flow heterogeneity on the enhancement of chemical reaction and the creation of spatially localized hotspots of reactivity for a broad range of systems ranging from kinetic limited

Highly sensitive SnO2 sensor via reactive laser-induced transfer

PubMed Central

Palla Papavlu, Alexandra; Mattle, Thomas; Temmel, Sandra; Lehmann, Ulrike; Hintennach, Andreas; Grisel, Alain; Wokaun, Alexander; Lippert, Thomas

2016-01-01

Gas sensors based on tin oxide (SnO2) and palladium doped SnO2 (Pd:SnO2) active materials are fabricated by a laser printing method, i.e. reactive laser-induced forward transfer (rLIFT). Thin films from tin based metal-complex precursors are prepared by spin coating and then laser transferred with high resolution onto sensor structures. The devices fabricated by rLIFT exhibit low ppm sensitivity towards ethanol and methane as well as good stability with respect to air, moisture, and time. Promising results are obtained by applying rLIFT to transfer metal-complex precursors onto uncoated commercial gas sensors. We could show that rLIFT onto commercial sensors is possible if the sensor structures are reinforced prior to printing. The rLIFT fabricated sensors show up to 4 times higher sensitivities then the commercial sensors (with inkjet printed SnO2). In addition, the selectivity towards CH4 of the Pd:SnO2 sensors is significantly enhanced compared to the pure SnO2 sensors. Our results indicate that the reactive laser transfer technique applied here represents an important technical step for the realization of improved gas detection systems with wide-ranging applications in environmental and health monitoring control. PMID:27118531

Microfluidic-SANS: insitu molecular insight into complex fluid processing and high throughput characterisation

NASA Astrophysics Data System (ADS)

Lopez, Carlos; Watanabe, Takaichi; Cabral, Joao; Graham, Peter; Porcar, Lionel; Martel, Anne

2014-03-01

The coupling of microfluidics and small angle neutron scattering (SANS) is successfully demonstrated for the first time. We have developed novel microdevices with suitably low SANS background and high pressure compatibility for the investigation of flow-induced phenomena and high throughput phase mapping of complex fluids. We successfully obtained scattering profiles from 50 micron channels, in 10s - 100s second acquisition times. The microfluidic geometry enables the variation of both flow type and magnitude, beyond traditional rheo-SANS setups, and is exceptionally well-suited for complex fluids due to the commensurability of relevant time and lengthscales. We demonstrate our approach by studying model flow responsive systems, including surfactant/co-surfactant/water mixtures, with well-known equilibrium phase behaviour,: sodium dodecyl sulfate (SDS)/octanol/brine, cetyltrimethyl ammonium chloride (C16TAC)/pentanol/water and a model microemulsion system (C10E4 /decane/ D20), as well as polyelectrolyte solutions. Finally, using an online micromixer we are able to implement a high throughput approach, scanning in excess of 10 scattering profiles/min for a continuous aqueous surfactant dilution over two decades in concentration.

Chemorheology of reactive systems: Finite element analysis

NASA Technical Reports Server (NTRS)

Douglas, C.; Roylance, D.

1982-01-01

The equations which govern the nonisothermal flow of reactive fluids are outlined, and the means by which finite element analysis is used to solve these equations for the sort of arbitrary boundary conditions encountered in industrial practice are described. The performance of the computer code is illustrated by several trial problems, selected more for their value in providing insight to polymer processing flows than as practical production problems. Although a good deal remains to be learned as to the performance and proper use of this numerical technique, it is undeniably useful in providing better understanding of today's complicated polymer processing problems.

Neural mechanisms of interference control in working memory: effects of interference expectancy and fluid intelligence.

PubMed

Burgess, Gregory C; Braver, Todd S

2010-09-20

A critical aspect of executive control is the ability to limit the adverse effects of interference. Previous studies have shown activation of left ventrolateral prefrontal cortex after the onset of interference, suggesting that interference may be resolved in a reactive manner. However, we suggest that interference control may also operate in a proactive manner to prevent effects of interference. The current study investigated the temporal dynamics of interference control by varying two factors - interference expectancy and fluid intelligence (gF) - that could influence whether interference control operates proactively versus reactively. A modified version of the recent negatives task was utilized. Interference expectancy was manipulated across task blocks by changing the proportion of recent negative (interference) trials versus recent positive (facilitation) trials. Furthermore, we explored whether gF affected the tendency to utilize specific interference control mechanisms. When interference expectancy was low, activity in lateral prefrontal cortex replicated prior results showing a reactive control pattern (i.e., interference-sensitivity during probe period). In contrast, when interference expectancy was high, bilateral prefrontal cortex activation was more indicative of proactive control mechanisms (interference-related effects prior to the probe period). Additional results suggested that the proactive control pattern was more evident in high gF individuals, whereas the reactive control pattern was more evident in low gF individuals. The results suggest the presence of two neural mechanisms of interference control, with the differential expression of these mechanisms modulated by both experimental (e.g., expectancy effects) and individual difference (e.g., gF) factors.

The direction of fluid flow during contact metamorphism of siliceous carbonate rocks: new data for the Monzoni and Predazzo aureoles, northern Italy, and a global review

NASA Astrophysics Data System (ADS)

Ferry, John M.; Wing, Boswell A.; Penniston-Dorland, Sarah C.; Rumble, Douglas

2002-03-01

Periclase formed in siliceous dolomitic marbles during contact metamorphism in the Monzoni and Predazzo aureoles, the Dolomites, northern Italy, by infiltration of the carbonate rocks by chemically reactive, H2O-rich fluids at 500 bar and 565-710 °C. The spatial distribution of periclase and oxygen isotope compositions is consistent with reactive fluid flow that was primarily vertical and upward in both aureoles with time-integrated flux ~5,000 and ~300 mol fluid/cm2 rock in the Monzoni and Predazzo aureoles, respectively. The new results for Monzoni and Predazzo are considered along with published studies of 13 other aureoles to draw general conclusions about the direction, amount, and controls on the geometry of reactive fluid flow during contact metamorphism of siliceous carbonate rocks. Flow in 12 aureoles was primarily vertically upward with and without a horizontal component directed away from the pluton. Fluid flow in two of the other three was primarily horizontal, directed from the pluton into the aureole. The direction of flow in the remaining aureole is uncertain. Earlier suggestions that fluid flow is often horizontal, directed toward the pluton, are likely explained by an erroneous assumption that widespread coexisting mineral reactants and products represent arrested prograde decarbonation reactions. With the exception of three samples from one aureole, time-integrated fluid flux was in the range 102-104 mol/cm2. Both the amount and direction of fluid flow are consistent with hydrodynamic models of contact metamorphism. The orientation of bedding and lithologic contacts appears to be the principal control over whether fluid flow was either primarily vertical or horizontal. Other pre-metamorphic structures, including dikes, faults, fold hinges, and fracture zones, served to channel fluid flow as well.

The direction of fluid flow during contact metamorphism of siliceous carbonate rocks: new data for the Monzoni and Predazzo aureoles, northern Italy, and a global review

NASA Astrophysics Data System (ADS)

Ferry, John; Wing, Boswell; Penniston-Dorland, Sarah; Rumble, Douglas

2001-11-01

Periclase formed in siliceous dolomitic marbles during contact metamorphism in the Monzoni and Predazzo aureoles, the Dolomites, northern Italy, by infiltration of the carbonate rocks by chemically reactive, H2O-rich fluids at 500 bar and 565-710 °C. The spatial distribution of periclase and oxygen isotope compositions is consistent with reactive fluid flow that was primarily vertical and upward in both aureoles with time-integrated flux 5,000 and 300 mol fluid/cm2 rock in the Monzoni and Predazzo aureoles, respectively. The new results for Monzoni and Predazzo are considered along with published studies of 13 other aureoles to draw general conclusions about the direction, amount, and controls on the geometry of reactive fluid flow during contact metamorphism of siliceous carbonate rocks. Flow in 12 aureoles was primarily vertically upward with and without a horizontal component directed away from the pluton. Fluid flow in two of the other three was primarily horizontal, directed from the pluton into the aureole. The direction of flow in the remaining aureole is uncertain. Earlier suggestions that fluid flow is often horizontal, directed toward the pluton, are likely explained by an erroneous assumption that widespread coexisting mineral reactants and products represent arrested prograde decarbonation reactions. With the exception of three samples from one aureole, time-integrated fluid flux was in the range 102-104 mol/cm2. Both the amount and direction of fluid flow are consistent with hydrodynamic models of contact metamorphism. The orientation of bedding and lithologic contacts appears to be the principal control over whether fluid flow was either primarily vertical or horizontal. Other pre-metamorphic structures, including dikes, faults, fold hinges, and fracture zones, served to channel fluid flow as well.

In-duct identification of fluid-borne source with high spatial resolution

NASA Astrophysics Data System (ADS)

Heo, Yong-Ho; Ih, Jeong-Guon; Bodén, Hans

2014-11-01

Source identification of acoustic characteristics of in-duct fluid machinery is required for coping with the fluid-borne noise. By knowing the acoustic pressure and particle velocity field at the source plane in detail, the sound generation mechanism of a fluid machine can be understood. The identified spatial distribution of the strength of major radiators would be useful for the low noise design. Conventional methods for measuring the source in a wide duct have not been very helpful in investigating the source properties in detail because their spatial resolution is improper for the design purpose. In this work, an inverse method to estimate the source parameters with a high spatial resolution is studied. The theoretical formulation including the evanescent modes and near-field measurement data is given for a wide duct. After validating the proposed method to a duct excited by an acoustic driver, an experiment on a duct system driven by an air blower is conducted in the presence of flow. A convergence test for the evanescent modes is performed to find the necessary number of modes to regenerate the measured pressure field precisely. By using the converged modal amplitudes, very-close near-field pressure to the source is regenerated and compared with the measured pressure, and the maximum error was -16.3 dB. The source parameters are restored from the converged modal amplitudes. Then, the distribution of source parameters on the driver and the blower is clearly revealed with a high spatial resolution for kR<1.84 in which range only plane waves can propagate to far field in a duct. Measurement using a flush mounted sensor array is discussed, and the removal of pure radial modes in the modeling is suggested.

Predicting the Noise of High Power Fluid Targets Using Computational Fluid Dynamics

NASA Astrophysics Data System (ADS)

Moore, Michael; Covrig Dusa, Silviu

The 2.5 kW liquid hydrogen (LH2) target used in the Qweak parity violation experiment is the highest power LH2 target in the world and the first to be designed with Computational Fluid Dynamics (CFD) at Jefferson Lab. The Qweak experiment determined the weak charge of the proton by measuring the parity-violating elastic scattering asymmetry of longitudinally polarized electrons from unpolarized liquid hydrogen at small momentum transfer (Q2 = 0 . 025 GeV2). This target satisfied the design goals of < 1 % luminosity reduction and < 5 % contribution to the total asymmetry width (the Qweak target achieved 2 % or 55ppm). State of the art time dependent CFD simulations are being developed to improve the predictions of target noise on the time scale of the electron beam helicity period. These predictions will be bench-marked with the Qweak target data. This work is an essential component in future designs of very high power low noise targets like MOLLER (5 kW, target noise asymmetry contribution < 25 ppm) and MESA (4.5 kW).

A New Domain of Reactivity for High-Valent Dinuclear [M(μ-O)2 M'] Complexes in Oxidation Reactions.

PubMed

Engelmann, Xenia; Yao, Shenglai; Farquhar, Erik R; Szilvási, Tibor; Kuhlmann, Uwe; Hildebrandt, Peter; Driess, Matthias; Ray, Kallol

2017-01-02

The strikingly different reactivity of a series of homo- and heterodinuclear [(M III )(μ-O) 2 (M III )'] 2+ (M=Ni; M'=Fe, Co, Ni and M=M'=Co) complexes with β-diketiminate ligands in electrophilic and nucleophilic oxidation reactions is reported, and can be correlated to the spectroscopic features of the [(M III )(μ-O) 2 (M III )'] 2+ core. In particular, the unprecedented nucleophilic reactivity of the symmetric [Ni III (μ-O) 2 Ni III ] 2+ complex and the decay of the asymmetric [Ni III (μ-O) 2 Co III ] 2+ core through aromatic hydroxylation reactions represent a new domain for high-valent bis(μ-oxido)dimetal reactivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nano- to Formation-Scale Estimates of Mineral-Specific Reactive Surface Area

NASA Astrophysics Data System (ADS)

Cole, D. R.; Swift, A.; Sheets, J.; Anovitz, L. M.

2017-12-01

Predictions of changes in fluid composition, coupled with the evolution of the solid matrix, include the generation and testing of reactive transport models. However, translating a heterogeneous natural system into physical and chemical model parameters, including the critical but poorly-constrained metric of fluid-accessible surface area, continues to challenge Earth scientists. Studies of carbon storage capacity, permeability, rock strain due to mineral dissolution and precipitation, or the prediction of rock evolution through diagenesis and weathering each consider macroscale outcomes of processes that often are critically impacted by rock surface geometry at the nanoscale. The approach taken here is to consider the whole vertical extent of a saline reservoir and then to address two questions. First, what is the accessible surface area for each major mineral, and for all adjacent pore sizes from <2 nm on up, within each major lithofacies in that formation? Second, with the formation thus divided into units of analysis, parameterized, and placed into geologic context, what constraints can be placed on reactive surface area as a function of mineral composition? A complex sandstone covering a substantial fraction of the quartz-K-feldspar-illite ternary is selected and mineral-specific surface area quantified using neutron scattering, nitrogen and mercury porosimetry, multi-signal high-resolution mineral mapping, and other techniques. For neutron scattering, scale-specific pore geometries enable more accurate translation of volume into surface area. By applying this workflow to all end-member lithologies of this reservoir formation, equations and maps of surface area as a function of position on a quartz-feldspar-clay ternary plot are developed for each major mineral. Results from this work therefore advance our ability to parameterize models not just for the particular formation studied, but for similar geologic units as well.

Aerodynamic Characterization of a Thin, High-Performance Airfoil for Use in Ground Fluids Testing

NASA Technical Reports Server (NTRS)

Broeren, Andy P.; Lee, Sam; Clark, Catherine

2013-01-01

The FAA has worked with Transport Canada and others to develop allowance times for aircraft operating in ice-pellet precipitation. Wind-tunnel testing has been carried out to better understand the flowoff characteristics and resulting aerodynamic effects of anti-icing fluids contaminated with ice pellets using a thin, high-performance wing section at the National Research Council of Canada Propulsion and Icing Wind Tunnel. The objective of this paper is to characterize the aerodynamic behavior of this wing section in order to better understand the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination. Aerodynamic performance data, boundary-layer surveys and flow visualization were conducted at a Reynolds number of approximately 6.0 x 10(exp 6) and a Mach number of 0.12. The clean, baseline model exhibited leading-edge stall characteristics including a leading-edge laminar separation bubble and minimal or no separation on the trailing edge of the main element or flap. These results were consistent with expected 2-D aerodynamics and showed no anomalies that could adversely affect the evaluation of anti-icing fluids and ice-pellet contamination on the wing. Tests conducted with roughness and leading-edge flow disturbances helped to explain the aerodynamic impact of the anti-icing fluids and contamination. The stalling characteristics of the wing section with fluid and contamination appear to be driven at least partially by the effects of a secondary wave of fluid that forms near the leading edge as the wing is rotated in the simulated takeoff profile. These results have provided a much more complete understanding of the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination on this wing section. This is important since these results are used, in part, to develop the ice-pellet allowance times that are applicable to many different airplanes.

Aerodynamic Characterization of a Thin, High-Performance Airfoil for Use in Ground Fluids Testing

NASA Technical Reports Server (NTRS)

Broeren, Andy P.; Lee, Sam; Clark, Catherine

2013-01-01

The FAA has worked with Transport Canada and others to develop allowance times for aircraft operating in ice-pellet precipitation. Wind-tunnel testing has been carried out to better understand the flowoff characteristics and resulting aerodynamic effects of anti-icing fluids contaminated with ice pellets using a thin, high-performance wing section at the National Research Council of Canada Propulsion and Icing Wind Tunnel. The objective of this paper is to characterize the aerodynamic behavior of this wing section in order to better understand the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination. Aerodynamic performance data, boundary-layer surveys and flow visualization were conducted at a Reynolds number of approximately 6.0×10(exp 6) and a Mach number of 0.12. The clean, baseline model exhibited leading-edge stall characteristics including a leading-edge laminar separation bubble and minimal or no separation on the trailing edge of the main element or flap. These results were consistent with expected 2-D aerodynamics and showed no anomalies that could adversely affect the evaluation of anti-icing fluids and ice-pellet contamination on the wing. Tests conducted with roughness and leading-edge flow disturbances helped to explain the aerodynamic impact of the anti-icing fluids and contamination. The stalling characteristics of the wing section with fluid and contamination appear to be driven at least partially by the effects of a secondary wave of fluid that forms near the leading edge as the wing is rotated in the simulated takeoff profile. These results have provided a much more complete understanding of the adverse aerodynamic effects of anti-icing fluids and ice-pellet contamination on this wing section. This is important since these results are used, in part, to develop the ice-pellet allowance times that are applicable to many different airplanes.

Predictive model for convective flows induced by surface reactivity contrast

NASA Astrophysics Data System (ADS)

Davidson, Scott M.; Lammertink, Rob G. H.; Mani, Ali

2018-05-01

Concentration gradients in a fluid adjacent to a reactive surface due to contrast in surface reactivity generate convective flows. These flows result from contributions by electro- and diffusio-osmotic phenomena. In this study, we have analyzed reactive patterns that release and consume protons, analogous to bimetallic catalytic conversion of peroxide. Similar systems have typically been studied using either scaling analysis to predict trends or costly numerical simulation. Here, we present a simple analytical model, bridging the gap in quantitative understanding between scaling relations and simulations, to predict the induced potentials and consequent velocities in such systems without the use of any fitting parameters. Our model is tested against direct numerical solutions to the coupled Poisson, Nernst-Planck, and Stokes equations. Predicted slip velocities from the model and simulations agree to within a factor of ≈2 over a multiple order-of-magnitude change in the input parameters. Our analysis can be used to predict enhancement of mass transport and the resulting impact on overall catalytic conversion, and is also applicable to predicting the speed of catalytic nanomotors.

High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

NASA Astrophysics Data System (ADS)

Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

2017-08-01

Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

A case of reactive arthritis due to Clostridium difficile colitis

PubMed Central

Essenmacher, Alex C.; Khurram, Nazish; Bismack, Gregory T.

2016-01-01

Reactive arthritis is an acute, aseptic, inflammatory arthropathy following an infectious process but removed from the site of primary infection. It is often attributed to genitourinary and enteric pathogens, such as Chlamydia, Salmonella, Shigella, Campylobacter, and Yersinia, in susceptible individuals. An uncommon and less recognized cause of this disease is preceding colonic infection with Clostridium difficile, an organism associated with pseudomembranous colitis and diarrhea in hospitalized patients and those recently exposed to antibiotics. Recognition of this association may be complicated by non-specific presentation of diarrhea, the interval between gastrointestinal and arthritic symptoms, and the wide differential in mono- and oligoarthritis. We present the case of a 61-year-old, hospitalized patient recently treated for C. difficile colitis who developed sudden, non-traumatic, right knee pain and swelling. Physical examination and radiographs disclosed joint effusion, and sterile aspiration produced cloudy fluid with predominant neutrophils and no growth on cultures. Diagnostic accuracy is enhanced by contemporaneous laboratory investigations excluding other entities such as gout and rheumatoid arthritis and other infections that typically precede reactive arthritis. Contribution of Clostridium infection to reactive arthritis is an obscure association frequently difficult to prove, but this organism is warranted inclusion in the differential of reactive arthritis. PMID:26908381

The effect of periodontal treatment on C-reactive protein: A clinical study.

PubMed

Kumar, Santosh; Shah, Samir; Budhiraja, Shilpa; Desai, Khushboo; Shah, Chirag; Mehta, Dhaval

2013-07-01

Chronic periodontitis in amultifactorial inflammatory disease which is caused by various microorganisms. Many studies have found close association between chronic periodontitis and C-reactive protein (CRP). CRPis an inflammatory marker which increases in all inflammatory condition. The present clinical study was designed to show the effect of periodontal treatment on the CRP levels of gingival crevicular fluid and to determine the effect of nonsurgical therapy in minimizing the CRP levels in chronic generalized periodontitis. Gingival crevicular fluid was collected using a micro capillary pipette that was hand calibrated at every 1 mm till 10 mm, from selected sites in the subjects on the 1st, 14th and 45th days. Decreased CRP levels of gingival crevicular fluid were observed at the end of the study. There was a 37% reduction in probing pocket depth and 45% gain in clinical attachment level and a reduction of about 57% after 14 days and 90% reduction of CRP levels in gingival crevicular fluid after 45 days. Thus, the results show that the presence of CRP level is more significant in gingival crevicular fluid and confirms the underlying inflammatory component of the disease activity in chronic periodontitis.

Crystallization of high-Ca chromium garnet upon interaction of serpentine, chromite, and Ca-bearing hydrous fluid

NASA Astrophysics Data System (ADS)

Chepurov, A. A.; Turkin, A. I.; Pokhilenko, N. P.

2017-10-01

The results of experimental modeling of the conditions of crystallization of high-Ca chromium garnets in the system serpentine-chromite-Ca-Cr-bearing hydrous fluid at a pressure of 5 GPa and temperature of 1300°C are reported. The mineral association including quantitatively predominant high-Mg olivine and diopside-rich clinopyroxene, bright-green garnet, and newly formed chrome spinel was formed. Garnet mostly crystallized around primary chromite grains and was characterized by a high concentration of CaO and Cr2O3. According to the chemical composition, garnets obtained are close to the uvarovite-pyrope varieties, which enter the composition of relatively rare natural paragenesis of garnet wehrlite. The experimental data obtained clearly show that high-Ca chromium garnets are formed in the reaction of chromite-bearing peridotite and Ca-rich fluid at high P-T parameters.

Preterm birth leads to hyper-reactive cognitive control processing and poor white matter organization in adulthood.

PubMed

Olsen, Alexander; Dennis, Emily L; Evensen, Kari Anne I; Husby Hollund, Ingrid Marie; Løhaugen, Gro C C; Thompson, Paul M; Brubakk, Ann-Mari; Eikenes, Live; Håberg, Asta K

2018-02-15

Individuals born preterm with very low birth weight (VLBW; birth weight ≤ 1500 g) are at high risk for perinatal brain injuries and deviant brain development, leading to increased chances of later cognitive, emotional, and behavioral problems. Here we investigated the neuronal underpinnings of both reactive and proactive cognitive control processes in adults with VLBW. We included 32 adults born preterm with VLBW (before 37th week of gestation) and 32 term-born controls (birth weight ≥10th percentile for gestational age) between 22 and 24 years of age that have been followed prospectively since birth. Participants performed a well-validated Not-X continuous performance test (CPT) adapted for use in a mixed block- and event-related fMRI protocol. BOLD fMRI and DTI data was acquired on a 3T scanner. Performance on the Not-X CPT was highly similar between groups. However, the VLBW group demonstrated hyper-reactive cognitive control processing and disrupted white matter organization. The hyper-reactive brain activation signature in VLBW adults was associated with lower gestational age, lower fluid intelligence score, and anxiety problems. Automated Multi-Atlas Tract Extraction (AutoMATE) analyses revealed that this disruption of normal brain function was accompanied by poorer white matter organization in the anterior thalamic radiation and the cingulum, as reflected in both reduced fractional anisotropy and increased mean diffusivity. These findings show that the preterm behavioral phenotype is associated with predominantly reactive-, rather than proactive cognitive control processing, as well as white matter abnormalities, that may underlie common difficulties that many preterm born individuals experience in everyday life. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Ultra‐high performance supercritical fluid chromatography of lignin‐derived phenols from alkaline cupric oxide oxidation

PubMed Central

Sun, Mingzhe; Lidén, Gunnar; Sandahl, Margareta

2016-01-01

Traditional chromatographic methods for the analysis of lignin‐derived phenolic compounds in environmental samples are generally time consuming. In this work, an ultra‐high performance supercritical fluid chromatography method with a diode array detector for the analysis of major lignin‐derived phenolic compounds produced by alkaline cupric oxide oxidation was developed. In an analysis of a collection of 11 representative monomeric lignin phenolic compounds, all compounds were clearly separated within 6 min with excellent peak shapes, with a limit of detection of 0.5–2.5 μM, a limit of quantification of 2.5–5.0 μM, and a dynamic range of 5.0–2.0 mM (R 2 > 0.997). The new ultra‐high performance supercritical fluid chromatography method was also applied for the qualitative and quantitative analysis of lignin‐derived phenolic compounds obtained upon alkaline cupric oxide oxidation of a commercial humic acid. Ten out of the previous eleven model compounds could be quantified in the oxidized humic acid sample. The high separation power and short analysis time obtained demonstrate for the first time that supercritical fluid chromatography is a fast and reliable technique for the analysis of lignin‐derived phenols in complex environmental samples. PMID:27452148

Physics based simulation of seismicity induced in the vicinity of a high-pressure fluid injection

NASA Astrophysics Data System (ADS)

McCloskey, J.; NicBhloscaidh, M.; Murphy, S.; O'Brien, G. S.; Bean, C. J.

2013-12-01

High-pressure fluid injection into subsurface is known, in some cases, to induce earthquakes in the surrounding volume. The increasing importance of ';fracking' as a potential source of hydrocarbons has made the seismic hazard from this effect an important issue the adjudication of planning applications and it is likely that poor understanding of the process will be used as justification of refusal of planning in Ireland and the UK. Here we attempt to understand some of the physical controls on the size and frequency of induced earthquakes using a physics-based simulation of the process and examine resulting earthquake catalogues The driver for seismicity in our simulations is identical to that used in the paper by Murphy et al. in this session. Fluid injection is simulated using pore fluid movement throughout a permeable layer from a high-pressure point source using a lattice Boltzmann scheme. Diffusivities and frictional parameters can be defined independently at individual nodes/cells allowing us to reproduce 3-D geological structures. Active faults in the model follow a fractal size distribution and exhibit characteristic event size, resulting in a power-law frequency-size distribution. The fluid injection is not hydraulically connected to the fault (i.e. fluid does not come into physical contact with the fault); however stress perturbations from the injection drive the seismicity model. The duration and pressure-time function of the fluid injection can be adjusted to model any given injection scenario and the rate of induced seismicity is controlled by the local structures and ambient stress field as well as by the stress perturbations resulting from the fluid injection. Results from the rate and state fault models of Murphy et al. are incorporated to include the effect of fault strengthening in seismically quite areas. Initial results show similarities with observed induced seismic catalogues. Seismicity is only induced where the active faults have not been

High throughput assay for evaluation of reactive carbonyl scavenging capacity.

PubMed

Vidal, N; Cavaille, J P; Graziani, F; Robin, M; Ouari, O; Pietri, S; Stocker, P

2014-01-01

Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal.

Reactivity Accountability Attributed to Reflector Poisons in the High Flux Isotope Reactor

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

Chandler, David; Maldonado, G Ivan; Primm, Trent

2009-12-01

The objective of this study is to develop a methodology to predict the reactivity impact as a function of outage time between cycles of 3He, 6Li, and other poisons in the High Flux Isotope Reactor s (HFIR) beryllium reflector. The reactivity worth at startup of the HFIR has been incorrectly predicted in the past after the reactor has been shut-down for long periods of time. The incorrect prediction was postulated to be due to the erroneous calculation of 3He buildup in the beryllium reflector. It is necessary to develop a better estimate of the start-of-cycle symmetric critical control element positionsmore » since if the estimated and actual symmetrical critical control element positions differ by more than $1.55 in reactivity (approximately one-half inch in control element startup position), HFIR is to be shutdown and a technical evaluation is performed to resolve the discrepancy prior to restart. 3He is generated and depleted during operation, but during an outage, the depletion of 3He ceases because it is a stable isotope. 3He is born from the radioactive decay of tritium, and thus the concentration of 3He increases during shutdown. SCALE, specifically the TRITON and CSAS5 control modules including the KENO V.A, COUPLE, and ORIGEN functional modules were utilized in this study. An equation relating the down time (td) to the change in symmetric control element position was generated and validated against measurements for approximately 40 HFIR operating cycles. The newly-derived correlation was shown to improve accuracy of predictions for long periods of down time.« less

Microfluidic co-flow of Newtonian and viscoelastic fluids for high-resolution separation of microparticles.

PubMed

Tian, Fei; Zhang, Wei; Cai, Lili; Li, Shanshan; Hu, Guoqing; Cong, Yulong; Liu, Chao; Li, Tiejun; Sun, Jiashu

2017-09-12

The microfluidic passive control of microparticles largely relies on the hydrodynamic effects of the carrier media such as Newtonian fluids and viscoelastic fluids. Yet the viscoelastic/Newtonian interfacial effect has been scarcely investigated, especially for high-resolution particle separation. Here we report a microfluidic co-flow of Newtonian (water or PBS) and viscoelastic fluids (PEO) for the size-dependent separation of microparticles. The co-flow condition generates a stable viscoelastic/Newtonian interface, giving rise to the wall-directed elastic lift forces that compete with the center-directed lift forces, and efficiently hinders the migration of microparticles from the Newtonian to the viscoelastic fluid in a size-dependent manner. An almost complete separation of a binary mixture of 1 μm and 2 μm polystyrene particles is achieved by the co-flow of water and a very dilute PEO solution (100 ppm), whereas the sole use of water or PEO could not lead to an efficient separation. This co-flow microfluidic system is also applied for the separation of Staphylococcus aureus (1 μm) from platelets (2-3 μm) with >90% efficiencies and purities.

Soy Protein Isolate As Fluid Loss Additive in Bentonite-Water-Based Drilling Fluids.

PubMed

Li, Mei-Chun; Wu, Qinglin; Song, Kunlin; Lee, Sunyoung; Jin, Chunde; Ren, Suxia; Lei, Tingzhou

2015-11-11

Wellbore instability and formation collapse caused by lost circulation are vital issues during well excavation in the oil industry. This study reports the novel utilization of soy protein isolate (SPI) as fluid loss additive in bentonite-water based drilling fluids (BT-WDFs) and describes how its particle size and concentration influence on the filtration property of SPI/BT-WDFs. It was found that high pressure homogenization (HPH)-treated SPI had superior filtration property over that of native SPI due to the improved ability for the plugging pore throat. HPH treatment also caused a significant change in the surface characteristic of SPI, leading to a considerable surface interaction with BT in aqueous solution. The concentration of SPI had a significant impact on the dispersion state of SPI/BT mixtures in aquesous solution. At low SPI concentrations, strong aggregations were created, resulting in the formation of thick, loose, high-porosity and high-permeability filter cakes and high fluid loss. At high SPI concentrations, intercatlated/exfoliated structures were generated, resulting in the formation of thin, compact, low-porosity and low-permeability filter cakes and low fluid loss. The SPI/BT-WDFs exhibited superior filtration property than pure BT-WDFs at the same solid concentraion, demonstrating the potential utilization of SPI as an effective, renewable, and biodegradable fluid loss reducer in well excavation applications.

Fluid pathways from mantle wedge up to forearc seafloor in the coseismic slip area of the 2011 Tohoku earthquake

NASA Astrophysics Data System (ADS)

Park, J. O.; Tsuru, T.; Fujie, G.; Kagoshima, T.; Sano, Y.

2017-12-01

A lot of fluids at subduction zones are exchanged between the solid Earth and ocean, affecting the earthquake and tsunami generation. New multi-channel seismic reflection and sub-bottom profiling data reveal normal and reverse faults as the fluid pathways in the coseismic slip area of the 2011 Tohoku earthquake (M9.0). Based on seismic reflection characteristics and helium isotope anomalies, we recognize variations in fluid pathways (i.e., faults) from the mantle wedge up to forearc seafloor in the Japan Trench margin. Some fluids are migrated from the mantle wedge along plate interface and then normal or reverse faults cutting through the overriding plate. Others from the mantle wedge are migrated directly up to seafloor along normal faults, without passing through the plate interface. Locations of the normal faults are roughly consistent with aftershocks of the 2011 Tohoku earthquake, which show focal mechanism of normal faulting. It is noticeable that landward-dipping normal faults developing down into Unit C (Cretaceous basement) from seafloor are dominant in the middle slope region where basal erosion is inferred to be most active. A high-amplitude, reverse-polarity reflection of the normal faults within Unit C suggests that the fluids are locally trapped along the faults in high pore pressures. The 2011 Tohoku mainshock and subsequent aftershocks could lead the pre-existing normal faults to be reactive and more porous so that the trapped fluids are easily transported up to seafloor through the faults. Elevated fluid pressures can decrease the effective normal stress for the fault plane, allowing easier slip of the landward-dipping normal fault and also enhancing its tsunamigenic potential.

Performance of homeostasis model assessment and serum high-sensitivity C-reactive protein for prediction of isolated post-load hyperglycaemia.

PubMed

Lai, Y-C; Li, H-Y; Hung, C-S; Lin, M-S; Shih, S-R; Ma, W-Y; Hua, C-H; Chuang, L-M; Sung, F-C; Wei, J-N

2013-03-01

To evaluate whether homeostasis model assessment and high-sensitivity C-reactive protein improve the prediction of isolated post-load hyperglycaemia. The subjects were 1458 adults without self-reported diabetes recruited between 2006 and 2010. Isolated post-load hyperglycaemia was defined as fasting plasma glucose < 7 mmol/l and 2-h post-load plasma glucose ≥ 11.1 mmol/l. Risk scores of isolated post-load hyperglycaemia were constructed by multivariate logistic regression. An independent group (n = 154) was enrolled from 2010 to 2011 to validate the models' performance. One hundred and twenty-three subjects (8.28%) were newly diagnosed as having diabetes mellitus. Among those with undiagnosed diabetes, 64 subjects (52%) had isolated post-load hyperglycaemia. Subjects with isolated post-load hyperglycaemia were older, more centrally obese and had higher blood pressure, HbA(1c), fasting plasma glucose, triglycerides, LDL cholesterol, high-sensitivity C-reactive protein and homeostasis model assessment of insulin resistance and lower homeostasis model assessment of β-cell function than those without diabetes. The risk scores included age, gender, BMI, homeostasis model assessment, high-sensitivity C-reactive protein and HbA(1c). The full model had high sensitivity (84%) and specificity (87%) and area under the receiver operating characteristic curve (0.91), with a cut-off point of 23.81; validation in an independent data set showed 88% sensitivity, 77% specificity and an area under curve of 0.89. Over half of those with undiagnosed diabetes had isolated post-load hyperglycaemia. Homeostasis model assessment and high-sensitivity C-reactive protein are useful to identify subjects with isolated post-load hyperglycaemia, with improved performance over fasting plasma glucose or HbA(1c) alone. © 2012 The Authors. Diabetic Medicine © 2012 Diabetes UK.

Fluids and sepsis: changing the paradigm of fluid therapy: a case report.

PubMed

Hariyanto, Hori; Yahya, Corry Quando; Widiastuti, Monika; Wibowo, Primartanto; Tampubolon, Oloan Eduard

2017-02-04

Over the past 16 years, sepsis management has been guided by large-volume fluid administration to achieve certain hemodynamic optimization as advocated in the Rivers protocol. However, the safety of such practice has been questioned because large-volume fluid administration is associated with fluid overload and carries the worst outcome in patients with sepsis. Researchers in multiple studies have declared that using less fluid leads to increased survival, but they did not describe how to administer fluids in a timely and appropriate manner. An 86-year-old previously healthy Sundanese man was admitted to the intensive care unit at our institution with septic shock, acute kidney injury, and respiratory distress. Standard care was implemented during his initial care in the high-care unit; nevertheless, his condition worsened, and he was transferred to the intensive care unit. We describe the timing of fluid administration and elaborate on the amount of fluids needed using a conservative fluid regimen in a continuum of resuscitated sepsis. Because fluid depletion in septic shock is caused by capillary leak and pathologic vasoplegia, continuation of fluid administration will drive intravascular fluid into the interstitial space, thereby producing marked tissue edema and disrupting vital oxygenation. Thus, fluids have the power to heal or kill. Therefore, management of patients with sepsis should entail early vasopressors with adequate fluid resuscitation followed by a conservative fluid regimen.

Double stratification effects in chemically reactive squeezed Sutterby fluid flow with thermal radiation and mixed convection

NASA Astrophysics Data System (ADS)

Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha

2018-03-01

A current analysis is carried out to study theoretically the mixed convection characteristics in squeezing flow of Sutterby fluid in squeezed channel. The constitutive equation of Sutterby model is utilized to characterize the rheology of squeezing phenomenon. Flow characteristics are explored with dual stratification. In flowing fluid which contains heat and mass transport, the first order chemical reaction and radiative heat flux affect the transport phenomenon. The systems of non-linear governing equations have been modulating which then solved by mean of convergent approach (Homotopy Analysis Method). The graphs are reported and illustrated for emerging parameters. Through graphical explanations, drag force, rate of heat and mass transport are conversed for different pertinent parameters. It is found that heat and mass transport rate decays with dominant double stratified parameters and chemical reaction parameter. The present two-dimensional examination is applicable in some of the engineering processes and industrial fluid mechanics.

Introducing new reactivity descriptors: "Bond reactivity indices." Comparison of the new definitions and atomic reactivity indices.

PubMed

Sánchez-Márquez, Jesús

2016-11-21

A new methodology to obtain reactivity indices has been defined. This is based on reactivity functions such as the Fukui function or the dual descriptor and makes it possible to project the information of reactivity functions over molecular orbitals instead of the atoms of the molecule (atomic reactivity indices). The methodology focuses on the molecule's natural bond orbitals (bond reactivity indices) because these orbitals (with physical meaning) have the advantage of being very localized, allowing the reaction site of an electrophile or nucleophile to be determined within a very precise molecular region. This methodology gives a reactivity index for every Natural Bond Orbital (NBO), and we have verified that they have equivalent information to the reactivity functions. A representative set of molecules has been used to test the new definitions. Also, the bond reactivity index has been related with the atomic reactivity one, and complementary information has been obtained from the comparison. Finally, a new atomic reactivity index has been defined and compared with previous definitions.

Struvite Crystallization of Anaerobic Digestive Fluid of Swine Manure Containing Highly Concentrated Nitrogen

PubMed Central

Lee, Eun Young; Oh, Min Hwan; Yang, Seung-Hak; Yoon, Tae Han

2015-01-01

In this study, the optimal operation factors for struvite crystallization for removing and recovering nitrogen and phosphorus from anaerobic digestive fluid of swine manure containing highly concentrated nitrogen was determined. Every experiment for the struvite crystallization reaction was conducted by placing 1,000 mL of digestion fluid in a 2,000 mL Erlenmeyer flask at various temperatures, pH, and mixing speed. Except for special circumstances, the digestion fluid was centrifuged (10,000 rpm, 10 min) and then the supernatant was used for the experiment at room temperature and 100 rpm. The optimal mole ratio of PO43−:Mg2+ was 1:1.5, and the pH effect ranging from 9 to 11 was similar, when mixed for 1 hour. Under this condition, the removal efficiency of NH4+-N and PO43−-P was 40% and 88.6%, respectively. X-shaped crystal was observed by light and scanning electron microscopy. In addition, struvite crystal structure was confirmed through X-ray diffraction analysis. PMID:26104412

THC-MP: High performance numerical simulation of reactive transport and multiphase flow in porous media

NASA Astrophysics Data System (ADS)

Wei, Xiaohui; Li, Weishan; Tian, Hailong; Li, Hongliang; Xu, Haixiao; Xu, Tianfu

2015-07-01

The numerical simulation of multiphase flow and reactive transport in the porous media on complex subsurface problem is a computationally intensive application. To meet the increasingly computational requirements, this paper presents a parallel computing method and architecture. Derived from TOUGHREACT that is a well-established code for simulating subsurface multi-phase flow and reactive transport problems, we developed a high performance computing THC-MP based on massive parallel computer, which extends greatly on the computational capability for the original code. The domain decomposition method was applied to the coupled numerical computing procedure in the THC-MP. We designed the distributed data structure, implemented the data initialization and exchange between the computing nodes and the core solving module using the hybrid parallel iterative and direct solver. Numerical accuracy of the THC-MP was verified through a CO2 injection-induced reactive transport problem by comparing the results obtained from the parallel computing and sequential computing (original code). Execution efficiency and code scalability were examined through field scale carbon sequestration applications on the multicore cluster. The results demonstrate successfully the enhanced performance using the THC-MP on parallel computing facilities.

A MEMS SOI-based piezoresistive fluid flow sensor

NASA Astrophysics Data System (ADS)

Tian, B.; Li, H. F.; Yang, H.; Song, D. L.; Bai, X. W.; Zhao, Y. L.

2018-02-01

In this paper, a SOI (silicon-on-insulator)-based piezoresistive fluid flow sensor is presented; the presented flow sensor mainly consists of a nylon sensing head, stainless steel cantilever beam, SOI sensor chip, printed circuit board, half-cylinder gasket, and stainless steel shell. The working principle of the sensor and some detailed contrastive analysis about the sensor structure were introduced since the nylon sensing head and stainless steel cantilever beam have distinct influence on the sensor performance; the structure of nylon sensing head and stainless steel cantilever beam is also discussed. The SOI sensor chip was fabricated using micro-electromechanical systems technologies, such as reactive ion etching and low pressure chemical vapor deposition. The designed fluid sensor was packaged and tested; a calibration installation system was purposely designed for the sensor experiment. The testing results indicated that the output voltage of the sensor is proportional to the square of the fluid flow velocity, which is coincident with the theoretical derivation. The tested sensitivity of the sensor is 3.91 × 10-4 V ms2/kg.

State-of-the-art review of computational fluid dynamics modeling for fluid-solids systems

NASA Astrophysics Data System (ADS)

Lyczkowski, R. W.; Bouillard, J. X.; Ding, J.; Chang, S. L.; Burge, S. W.

1994-05-01

As the result of 15 years of research (50 staff years of effort) Argonne National Laboratory (ANL), through its involvement in fluidized-bed combustion, magnetohydrodynamics, and a variety of environmental programs, has produced extensive computational fluid dynamics (CFD) software and models to predict the multiphase hydrodynamic and reactive behavior of fluid-solids motions and interactions in complex fluidized-bed reactors (FBR's) and slurry systems. This has resulted in the FLUFIX, IRF, and SLUFIX computer programs. These programs are based on fluid-solids hydrodynamic models and can predict information important to the designer of atmospheric or pressurized bubbling and circulating FBR, fluid catalytic cracking (FCC) and slurry units to guarantee optimum efficiency with minimum release of pollutants into the environment. This latter issue will become of paramount importance with the enactment of the Clean Air Act Amendment (CAAA) of 1995. Solids motion is also the key to understanding erosion processes. Erosion rates in FBR's and pneumatic and slurry components are computed by ANL's EROSION code to predict the potential metal wastage of FBR walls, intervals, feed distributors, and cyclones. Only the FLUFIX and IRF codes will be reviewed in the paper together with highlights of the validations because of length limitations. It is envisioned that one day, these codes with user-friendly pre- and post-processor software and tailored for massively parallel multiprocessor shared memory computational platforms will be used by industry and researchers to assist in reducing and/or eliminating the environmental and economic barriers which limit full consideration of coal, shale, and biomass as energy sources; to retain energy security; and to remediate waste and ecological problems.

Persistent latent tuberculosis reactivation risk in United States immigrants.

PubMed

Walter, Nicholas D; Painter, John; Parker, Matthew; Lowenthal, Phillip; Flood, Jennifer; Fu, Yunxin; Asis, Redentor; Reves, Randall

2014-01-01

Current guidelines limit latent tuberculosis infection (LTBI) evaluation to persons in the United States less than or equal to 5 years based on the assumption that high TB rates among recent entrants are attributable to high LTBI reactivation risk, which declines over time. We hypothesized that high postarrival TB rates may instead be caused by imported active TB. Estimate reactivation and imported TB in an immigrant cohort. We linked preimmigration records from a cohort of California-bound Filipino immigrants during 2001-2010 with subsequent TB reports. TB was likely LTBI reactivation if the immigrant had no evidence of active TB at preimmigration examination, likely imported if preimmigration radiograph was abnormal and TB was reported less than or equal to 6 months after arrival, and likely reactivation of inactive TB if radiograph was abnormal but TB was reported more than 6 months after arrival. Among 123,114 immigrants, 793 TB cases were reported. Within 1 year of preimmigration examination, 85% of TB was imported; 6 and 9% were reactivation of LTBI and inactive TB, respectively. Conversely, during Years 2-9 after U.S. entry, 76 and 24% were reactivation of LTBI and inactive TB, respectively. The rate of LTBI reactivation (32 per 100,000) did not decline during Years 1-9. High postarrival TB rates were caused by detection of imported TB through active postarrival surveillance. Among immigrants without active TB at baseline, reported TB did not decline over 9 years, indicating sustained high risk of LTBI reactivation. Revised guidelines should support LTBI screening and treatment more than 5 years after U.S. arrival.

Dynamic modeling of injection-induced fault reactivation and ground motion and impact on surface structures and human perception

DOE PAGES

Rutqvist, Jonny; Cappa, Frederic; Rinaldi, Antonio P.; ...

2014-12-31

We summarize recent modeling studies of injection-induced fault reactivation, seismicity, and its potential impact on surface structures and nuisance to the local human population. We used coupled multiphase fluid flow and geomechanical numerical modeling, dynamic wave propagation modeling, seismology theories, and empirical vibration criteria from mining and construction industries. We first simulated injection-induced fault reactivation, including dynamic fault slip, seismic source, wave propagation, and ground vibrations. From co-seismic average shear displacement and rupture area, we determined the moment magnitude to about M w = 3 for an injection-induced fault reactivation at a depth of about 1000 m. We then analyzedmore » the ground vibration results in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and frequency content, with comparison to the U.S. Bureau of Mines’ vibration criteria for cosmetic damage to buildings, as well as human-perception vibration limits. For the considered synthetic M w = 3 event, our analysis showed that the short duration, high frequency ground motion may not cause any significant damage to surface structures, and would not cause, in this particular case, upward CO 2 leakage, but would certainly be felt by the local population.« less

Influence of inert gases on the reactive high power pulsed magnetron sputtering process of carbon-nitride thin films

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

Schmidt, Susann; Czigany, Zsolt; Greczynski, Grzegorz

2013-01-15

The influence of inert gases (Ne, Ar, Kr) on the sputter process of carbon and carbon-nitride (CN{sub x}) thin films was studied using reactive high power pulsed magnetron sputtering (HiPIMS). Thin solid films were synthesized in an industrial deposition chamber from a graphite target. The peak target current during HiPIMS processing was found to decrease with increasing inert gas mass. Time averaged and time resolved ion mass spectroscopy showed that the addition of nitrogen, as reactive gas, resulted in less energetic ion species for processes employing Ne, whereas the opposite was noticed when Ar or Kr were employed as inertmore » gas. Processes in nonreactive ambient showed generally lower total ion fluxes for the three different inert gases. As soon as N{sub 2} was introduced into the process, the deposition rates for Ne and Ar-containing processes increased significantly. The reactive Kr-process, in contrast, showed slightly lower deposition rates than the nonreactive. The resulting thin films were characterized regarding their bonding and microstructure by x-ray photoelectron spectroscopy and transmission electron microscopy. Reactively deposited CN{sub x} thin films in Ar and Kr ambient exhibited an ordering toward a fullerene-like structure, whereas carbon and CN{sub x} films deposited in Ne atmosphere were found to be amorphous. This is attributed to an elevated amount of highly energetic particles observed during ion mass spectrometry and indicated by high peak target currents in Ne-containing processes. These results are discussed with respect to the current understanding of the structural evolution of a-C and CN{sub x} thin films.« less

Crevicular fluid biomarkers and periodontal disease progression.

PubMed

Kinney, Janet S; Morelli, Thiago; Oh, Min; Braun, Thomas M; Ramseier, Christoph A; Sugai, Jim V; Giannobile, William V

2014-02-01

Assess the ability of a panel of gingival crevicular fluid (GCF) biomarkers as predictors of periodontal disease progression (PDP). In this study, 100 individuals participated in a 12-month longitudinal investigation and were categorized into four groups according to their periodontal status. GCF, clinical parameters and saliva were collected bi-monthly. Subgingival plaque and serum were collected bi-annually. For 6 months, no periodontal treatment was provided. At 6 months, patients received periodontal therapy and continued participation from 6 to 12 months. GCF samples were analysed by ELISA for MMP-8, MMP-9, Osteoprotegerin, C-reactive Protein and IL-1β. Differences in median levels of GCF biomarkers were compared between stable and progressing participants using Wilcoxon Rank Sum test (p = 0.05). Clustering algorithm was used to evaluate the ability of oral biomarkers to classify patients as either stable or progressing. Eighty-three individuals completed the 6-month monitoring phase. With the exception of GCF C-reactive protein, all biomarkers were significantly higher in the PDP group compared to stable patients. Clustering analysis showed highest sensitivity levels when biofilm pathogens and GCF biomarkers were combined with clinical measures, 74% (95% CI = 61, 86). Signature of GCF fluid-derived biomarkers combined with pathogens and clinical measures provides a sensitive measure for discrimination of PDP (ClinicalTrials.gov NCT00277745). © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Measuring the reactivity of a silicon-terminated probe

NASA Astrophysics Data System (ADS)

Sweetman, Adam; Stirling, Julian; Jarvis, Samuel Paul; Rahe, Philipp; Moriarty, Philip

2016-09-01

It is generally accepted that the exposed surfaces of silicon crystals are highly reactive due to the dangling bonds which protrude into the vacuum. However, surface reconstruction not only modifies the reactivity of bulk silicon crystals, but also plays a key role in determining the properties of silicon nanocrystals. In this study we probe the reactivity of silicon clusters at the end of a scanning probe tip by examining their interaction with closed-shell fullerene molecules. Counter to intuitive expectations, many silicon clusters do not react strongly with the fullerene cage, and we find that only specific highly oriented clusters have sufficient reactivity to break open the existing carbon-carbon bonds.

Using supercritical fluids to refine hydrocarbons

DOEpatents

Yarbro, Stephen Lee

2015-06-09

A system and method for reactively refining hydrocarbons, such as heavy oils with API gravities of less than 20 degrees and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure, using a selected fluid at supercritical conditions. A reaction portion of the system and method delivers lightweight, volatile hydrocarbons to an associated contacting unit which operates in mixed subcritical/supercritical or supercritical modes. Using thermal diffusion, multiphase contact, or a momentum generating pressure gradient, the contacting unit separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques.

Micromachined Fluid Inertial Sensors

PubMed Central

Liu, Shiqiang; Zhu, Rong

2017-01-01

Micromachined fluid inertial sensors are an important class of inertial sensors, which mainly includes thermal accelerometers and fluid gyroscopes, which have now been developed since the end of the last century for about 20 years. Compared with conventional silicon or quartz inertial sensors, the fluid inertial sensors use a fluid instead of a solid proof mass as the moving and sensitive element, and thus offer advantages of simple structures, low cost, high shock resistance, and large measurement ranges while the sensitivity and bandwidth are not competitive. Many studies and various designs have been reported in the past two decades. This review firstly introduces the working principles of fluid inertial sensors, followed by the relevant research developments. The micromachined thermal accelerometers based on thermal convection have developed maturely and become commercialized. However, the micromachined fluid gyroscopes, which are based on jet flow or thermal flow, are less mature. The key issues and technologies of the thermal accelerometers, mainly including bandwidth, temperature compensation, monolithic integration of tri-axis accelerometers and strategies for high production yields are also summarized and discussed. For the micromachined fluid gyroscopes, improving integration and sensitivity, reducing thermal errors and cross coupling errors are the issues of most concern. PMID:28216569

Photochemical modeling of emissions trading of highly reactive volatile organic compounds in Houston, Texas. 1. Reactivity based trading and potential for ozone hot spot formation.

PubMed

Wang, Linlin; Thompson, Tammy; McDonald-Buller, Elena C; Webb, Alba; Allen, David T

2007-04-01

As part of the State Implementation Plan for attaining the National Ambient Air Quality Standard for ozone, the Texas Commission of Environmental Quality has created a Highly Reactive Volatile Organic Compounds (HRVOC) Emissions Cap and Trade Program for industrial point sources in the Houston/Galveston/Brazoria area. This program has a number of unique features, including its focus on a limited group of ozone precursors and its provisions for trading emissions based on atmospheric reactivity. This series of papers examines the potential air quality impacts of this new emission trading program through photochemical modeling of potential trading scenarios; this first paper in the series describes the air quality modeling methods used to assess potential trades, the potential for localized increases in ozone concentrations (ozone "hot spots") due to HRVOC emission trading, and the use of reactivity scales in the trading. When HRVOC emissions are traded on a mass basis, the simulations indicate that trading of HRVOC allowances between facilities resulted in less than 0.15 ppb (<0.13%) and 0.06 ppb (<0.06%) increases in predicted maximum, area-wide 1-h averaged and 8-h averaged ozone concentrations, respectively. Maximum decreases in ozone concentrations associated with trading, as opposed to across-the-board reductions, were larger than the increases. All of these changes are small compared to the maximum changes in ozone concentrations due to the VOC emissions from these sources (up to 5-10 ppb for 8 h averages; up to 30 ppb for 1-h averages). When emissions of HRVOCs are traded for other, less reactive emissions, on a reactivity weighted basis, air quality simulations indicate that daily maximum ozone concentrations increased by less than 0.3%. Because these relatively small changes (< 1%) are for unlikely trading scenarios designed to produce a maximum change in ozone concentrations (all emissions traded into localized regions), the simulations indicate that the

Fluid Dynamics of a High Aspect-Ratio Jet

NASA Technical Reports Server (NTRS)

Munro, Scott E.; Ahuja, K. K.

2003-01-01

Circulation control wings are a type of pneumatic high-lift device that have been extensively researched as to their aerodynamic benefits. However, there has been little research into the possible airframe noise reduction benefits of a circulation control wing. The key element of noise is the jet noise associated with the jet sheet emitted from the blowing slot. High aspect-ratio jet acoustic results (aspect-ratios from 100 to 3,000) from a related study showed that the jet noise of this type of jet was proportional to the slot height to the 3/2 power and slot width to the 1/2 power. Fluid dynamic experiments were performed in the present study on the high aspect-ratio nozzle to gain understanding of the flow characteristics in an effort to relate the acoustic results to flow parameters. Single hot-wire experiments indicated that the jet exhaust from the high aspect-ratio nozzle was similar to a 2-d turbulent jet. Two-wire space-correlation measurements were performed to attempt to find a relationship between the slot height of the jet and the length-scale of the flow noise generating turbulence structure. The turbulent eddy convection velocity was also calculated, and was found to vary with the local centerline velocity, and also as a function of the frequency of the eddy.

Reactive Transport Modeling of Microbe-mediated Fe (II) Oxidation for Enhanced Oil Recovery

NASA Astrophysics Data System (ADS)

Surasani, V.; Li, L.

2011-12-01

Microbially Enhanced Oil Recovery (MEOR) aims to improve the recovery of entrapped heavy oil in depleted reservoirs using microbe-based technology. Reservoir ecosystems often contain diverse microbial communities those can interact with subsurface fluids and minerals through a network of nutrients and energy fluxes. Microbe-mediated reactions products include gases, biosurfactants, biopolymers those can alter the properties of oil and interfacial interactions between oil, brine, and rocks. In addition, the produced biomass and mineral precipitates can change the reservoir permeability profile and increase sweeping efficiency. Under subsurface conditions, the injection of nitrate and Fe (II) as the electron acceptor and donor allows bacteria to grow. The reaction products include minerals such as Fe(OH)3 and nitrogen containing gases. These reaction products can have large impact on oil and reservoir properties and can enhance the recovery of trapped oil. This work aims to understand the Fe(II) oxidation by nitrate under conditions relevant to MEOR. Reactive transport modeling is used to simulate the fluid flow, transport, and reactions involved in this process. Here we developed a complex reactive network for microbial mediated nitrate-dependent Fe (II) oxidation that involves both thermodynamic controlled aqueous reactions and kinetic controlled Fe (II) mineral reaction. Reactive transport modeling is used to understand and quantify the coupling between flow, transport, and reaction processes. Our results identify key parameter controls those are important for the alteration of permeability profile under field conditions.

Deposition of highly textured AlN thin films by reactive high power impulse magnetron sputtering

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

Moreira, Milena A.; Törndahl, Tobias; Katardjiev, Ilia

2015-03-15

Aluminum nitride thin films were deposited by reactive high power impulse magnetron sputtering (HiPIMS) and pulsed direct-current on Si (100) and textured Mo substrates, where the same deposition conditions were used for both techniques. The films were characterized by x-ray diffraction and atomic force microscopy. The results show a pronounced improvement in the AlN crystalline texture for all films deposited by HiPIMS on Si. Already at room temperature, the HiPIMS films exhibited a strong preferred (002) orientation and at 400 °C, no contributions from other orientations were detected. Despite the low film thickness of only 200 nm, an ω-scan full width atmore » half maximum value of 5.1° was achieved on Si. The results are attributed to the high ionization of sputtered material achieved in HiPIMS. On textured Mo, there was no significant difference between the deposition techniques.« less

Electroosmotic flow of Phan-Thien-Tanner fluids at high zeta potentials: An exact analytical solution

NASA Astrophysics Data System (ADS)

Sarma, Rajkumar; Deka, Nabajit; Sarma, Kuldeep; Mondal, Pranab Kumar

2018-06-01

We present a mathematical model to study the electroosmotic flow of a viscoelastic fluid in a parallel plate microchannel with a high zeta potential, taking hydrodynamic slippage at the walls into account in the underlying analysis. We use the simplified Phan-Thien-Tanner (s-PTT) constitutive relationships to describe the rheological behavior of the viscoelastic fluid, while Navier's slip law is employed to model the interfacial hydrodynamic slip. Here, we derive analytical solutions for the potential distribution, flow velocity, and volumetric flow rate based on the complete Poisson-Boltzmann equation (without considering the frequently used Debye-Hückel linear approximation). For the underlying electrokinetic transport, this investigation primarily reveals the influence of fluid rheology, wall zeta potential as modulated by the interfacial electrochemistry and interfacial slip on the velocity distribution, volumetric flow rate, and fluid stress, as well as the apparent viscosity. We show that combined with the viscoelasticity of the fluid, a higher wall zeta potential and slip coefficient lead to a phenomenal enhancement in the volumetric flow rate. We believe that this analysis, besides providing a deep theoretical insight to interpret the transport process, will also serve as a fundamental design tool for microfluidic devices/systems under electrokinetic influence.

[Hyper-reactive malarial splenomegaly].

PubMed

Maazoun, F; Deschamps, O; Barros-Kogel, E; Ngwem, E; Fauchet, N; Buffet, P; Froissart, A

2015-11-01

Hyper-reactive malarial splenomegaly is a rare and severe form of chronic malaria. This condition is a common cause of splenomegaly in endemic areas. The pathophysiology of hyper-reactive malarial splenomegaly involves an intense immune reaction (predominantly B cell-driven) to repeated/chronic infections with Plasmodium sp. The diagnosis may be difficult, due to a poorly specific clinical presentation (splenomegaly, fatigue, cytopenias), a long delay between residence in a malaria-endemic area and onset of symptoms, and a frequent absence of parasites on conventional thin and thick blood smears. A strongly contributive laboratory parameter is the presence of high levels of total immunoglobulin M. When the diagnostic of hyper-reactive malarial splenomegaly is considered, search for anti-Plasmodium antibodies and Plasmodium nucleic acids (genus and species) by PCR is useful. Diagnosis of hyper-reactive malarial splenomegaly relies on the simultaneous presence of epidemiological, clinical, biological and follow-up findings. Regression of both splenomegaly and hypersplenism following antimalarial therapy allows the differential diagnosis with splenic lymphoma, a common complication of hyper-reactive malarial splenomegaly. Although rare in Western countries, hyper-reactive malarial splenomegaly deserves increased medical awareness to reduce the incidence of incorrect diagnosis, to prevent progression to splenic lymphoma and to avoid splenectomy. Copyright © 2015 Société nationale française de médecine interne (SNFMI). Published by Elsevier SAS. All rights reserved.

Oral Fluids as a Live-Animal Sample Source for Evaluating Cross-Reactivity and Cross-Protection following Intranasal Influenza A Virus Vaccination in Pigs.

PubMed

Hughes, Holly R; Vincent, Amy L; Brockmeier, Susan L; Gauger, Phillip C; Pena, Lindomar; Santos, Jefferson; Braucher, Douglas R; Perez, Daniel R; Loving, Crystal L

2015-10-01

In North American swine, there are numerous antigenically distinct H1 influenza A virus (IAV) variants currently circulating, making vaccine development difficult due to the inability to formulate a vaccine that provides broad cross-protection. Experimentally, live-attenuated influenza virus (LAIV) vaccines demonstrate increased cross-protection compared to inactivated vaccines. However, there is no standardized assay to predict cross-protection following LAIV vaccination. Hemagglutination-inhibiting (HI) antibody in serum is the gold standard correlate of protection following IAV vaccination. LAIV vaccination does not induce a robust serum HI antibody titer; however, a local mucosal antibody response is elicited. Thus, a live-animal sample source that could be used to evaluate LAIV immunogenicity and cross-protection is needed. Here, we evaluated the use of oral fluids (OF) and nasal wash (NW) collected after IAV inoculation as a live-animal sample source in an enzyme-linked immunosorbent assay (ELISA) to predict cross-protection in comparison to traditional serology. Both live-virus exposure and LAIV vaccination provided heterologous protection, though protection was greatest against more closely phylogenetically related viruses. IAV-specific IgA was detected in NW and OF samples and was cross-reactive to representative IAV from each H1 cluster. Endpoint titers of cross-reactive IgA in OF from pigs exposed to live virus was associated with heterologous protection. While LAIV vaccination provided significant protection, LAIV immunogenicity was reduced compared to live-virus exposure. These data suggest that OF from pigs inoculated with wild-type IAV, with surface genes that match the LAIV seed strain, could be used in an ELISA to assess cross-protection and the antigenic relatedness of circulating and emerging IAV in swine. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

TOUGHREACT Version 2.0: A simulator for subsurface reactive transport under non-isothermal multiphase flow conditions

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

Xu, T.; Spycher, N.; Sonnenthal, E.

2010-08-01

TOUGHREACT is a numerical simulation program for chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media, and was developed by introducing reactive chemistry into the multiphase fluid and heat flow simulator TOUGH2 V2. The first version of TOUGHREACT was released to the public through the U.S. Department of Energy's Energy Science and Technology Software Center (ESTSC) in August 2004. It is among the most frequently requested of ESTSC's codes. The code has been widely used for studies in CO{sub 2} geological sequestration, nuclear waste isolation, geothermal energy development, environmental remediation, and increasingly for petroleum applications. Over themore » past several years, many new capabilities have been developed, which were incorporated into Version 2 of TOUGHREACT. Major additions and improvements in Version 2 are discussed here, and two application examples are presented: (1) long-term fate of injected CO{sub 2} in a storage reservoir and (2) biogeochemical cycling of metals in mining-impacted lake sediments.« less

The acute phase response of C3, C5, ceruloplasmin, and C-reactive protein induced by turpentine pleurisy in the rabbit.

PubMed Central

Giclas, P. C.; Manthei, U.; Strunk, R. C.

1985-01-01

Concentrations of five serum proteins, C3, C5, ceruloplasmin, C-reactive protein, and albumin, have been measured during the acute phase response in rabbits with turpentine-induced pleurisy. C-reactive protein concentrations in the circulation rose abruptly between 12 and 36 hours to a level greater than 50 times the pretreatment concentration, then returned to undetectable amounts by 96 hours. C3 and ceruloplasmin both showed some increase in concentration by 12 hours and reached their maximum concentrations of two to three times the baseline levels 48-72 hours after the turpentine treatment. Concentrations were still elevated at 120 hours, after which time they gradually returned to normal. C5 and albumin concentrations in the turpentine-treated rabbits did not differ from the baseline concentrations. The same five proteins were measured in the inflammatory exudate. C-reactive protein was not detectable at any of the time points. C3, C5, ceruloplasmin, and albumin were present in normal pleural fluid at roughly half their serum concentrations. The activities of C3, C5, and ceruloplasmin were low in the early exudate, but C3 and C5 activity rose relative to their concentrations in the later samples of pleural fluid. The specific activities of C3 and C5 were higher in the pleural fluid at 72 hours than in plasma, while that of ceruloplasmin remained less in the pleural fluid than in plasma throughout the experiment. The involvement of these proteins and their relation to the inflammatory response are discussed. Images Figure 6 PMID:2409807

Self-assembled titanium calcium oxide nanopatterns as versatile reactive nanomasks for dry etching lithographic transfer with high selectivity.

PubMed

Faustini, Marco; Drisko, Glenna L; Letailleur, Alban A; Montiel, Rafael Salas; Boissière, Cédric; Cattoni, Andrea; Haghiri-Gosnet, Anne Marie; Lerondel, Gilles; Grosso, David

2013-02-07

We report the simple preparation of ultra-thin self-assembled nanoperforated titanium calcium oxide films and their use as reactive nanomasks for selective dry etching of silicon. This novel reactive nanomask is composed of TiO(2) in which up to 50% of Ti was replaced by Ca (Ca(x)Ti(1-x)O(2-x)). The system was prepared by evaporation induced self-assembly of dip-coated solution of CaCl(2), TiCl(4) and poly(butadiene-block-ethylene oxide) followed by 5 min of thermal treatment at 500 °C in air. The mask exhibits enhanced selectivity by forming a CaF(2) protective layer in the presence of a chemically reactive fluorinated plasma. In particular it is demonstrated that ordered nano-arrays of dense Si pillars, or deep cylindrical wells, with high aspect ratio i.e. lateral dimensions as small as 20 nm and height up to 200 nm, can be formed. Both wells and pillars were formed by tuning the morphology and the homogeneity of the deposited mask. The mask preparation is extremely fast and simple, low-cost and easily scalable. Its combination with reactive ion etching constitutes one of the first examples of what can be achieved when sol-gel chemistry is coupled with top-down technologies. The resulting Si nanopatterns and nanostructures are of high interest for applications in many fields of nanotechnology including electronics and optics. This work extends and diversifies the toolbox of nanofabrication methods.

Pyrolysis process for producing condensed stabilized hydrocarbons utilizing a beneficially reactive gas

DOEpatents

Durai-Swamy, Kandaswamy

1982-01-01

In a process for recovery of values contained in solid carbonaceous material, the solid carbonaceous material is comminuted and then subjected to pyrolysis, in the presence of a carbon containing solid particulate source of heat and a beneficially reactive transport gas in a transport flash pyrolysis reactor, to form a pyrolysis product stream. The pyrolysis product stream contains a gaseous mixture and particulate solids. The solids are separated from the gaseous mixture to form a substantially solids-free gaseous stream which comprises volatilized hydrocarbon free radicals newly formed by pyrolysis. Preferably the solid particulate source of heat is formed by oxidizing part of the separated particulate solids. The beneficially reactive transport gas inhibits the reactivity of the char product and the carbon-containing solid particulate source of heat. Condensed stabilized hydrocarbons are obtained by quenching the gaseous mixture stream with a quench fluid which contains a capping agent for stabilizing and terminating newly formed volatilized hydrocarbon free radicals. The capping agent is partially depleted of hydrogen by the stabilization and termination reaction. Hydrocarbons of four or more carbon atoms in the gaseous mixture stream are condensed. A liquid stream containing the stabilized liquid product is then treated or separated into various fractions. A liquid containing the hydrogen depleted capping agent is hydrogenated to form a regenerated capping agent. At least a portion of the regenerated capping agent is recycled to the quench zone as the quench fluid. In another embodiment capping agent is produced by the process, separated from the liquid product mixture, and recycled.

Transport and Reactive Flow Modelling Using A Particle Tracking Method Based on Continuous Time Random Walks

NASA Astrophysics Data System (ADS)

Oliveira, R.; Bijeljic, B.; Blunt, M. J.; Colbourne, A.; Sederman, A. J.; Mantle, M. D.; Gladden, L. F.

2017-12-01

Mixing and reactive processes have a large impact on the viability of enhanced oil and gas recovery projects that involve acid stimulation and CO2 injection. To achieve a successful design of the injection schemes an accurate understanding of the interplay between pore structure, flow and reactive transport is necessary. Dependent on transport and reactive conditions, this complex coupling can also be dependent on initial rock heterogeneity across a variety of scales. To address these issues, we devise a new method to study transport and reactive flow in porous media at multiple scales. The transport model is based on an efficient Particle Tracking Method based on Continuous Time Random Walks (CTRW-PTM) on a lattice. Transport is modelled using an algorithm described in Rhodes and Blunt (2006) and Srinivasan et al. (2010); this model is expanded to enable for reactive flow predictions in subsurface rock undergoing a first-order fluid/solid chemical reaction. The reaction-induced alteration in fluid/solid interface is accommodated in the model through changes in porosity and flow field, leading to time dependent transport characteristics in the form of transit time distributions which account for rock heterogeneity change. This also enables the study of concentration profiles at the scale of interest. Firstly, we validate transport model by comparing the probability of molecular displacement (propagators) measured by Nuclear Magnetic Resonance (NMR) with our modelled predictions for concentration profiles. The experimental propagators for three different porous media of increasing complexity, a beadpack, a Bentheimer sandstone and a Portland carbonate, show a good agreement with the model. Next, we capture the time evolution of the propagators distribution in a reactive flow experiment, where hydrochloric acid is injected into a limestone rock. We analyse the time-evolving non-Fickian signatures for the transport during reactive flow and observe an increase in

Fluid absorption solar energy receiver

NASA Technical Reports Server (NTRS)

Bair, Edward J.

1993-01-01

A conventional solar dynamic system transmits solar energy to the flowing fluid of a thermodynamic cycle through structures which contain the gas and thermal energy storage material. Such a heat transfer mechanism dictates that the structure operate at a higher temperature than the fluid. This investigation reports on a fluid absorption receiver where only a part of the solar energy is transmitted to the structure. The other part is absorbed directly by the fluid. By proportioning these two heat transfer paths the energy to the structure can preheat the fluid, while the energy absorbed directly by the fluid raises the fluid to its final working temperature. The surface temperatures need not exceed the output temperature of the fluid. This makes the output temperature of the gas the maximum temperature in the system. The gas can have local maximum temperatures higher than the output working temperature. However local high temperatures are quickly equilibrated, and since the gas does not emit radiation, local high temperatures do not result in a radiative heat loss. Thermal radiation, thermal conductivity, and heat exchange with the gas all help equilibrate the surface temperature.

Selective evaporation of focusing fluid in two-fluid hydrodynamic print head.

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

Keicher, David M.; Cook, Adam W.

The work performed in this project has demonstrated the feasibility to use hydrodynamic focusing of two fluid steams to create a novel micro printing technology for electronics and other high performance applications. Initial efforts focused solely on selective evaporation of the sheath fluid from print stream provided insight in developing a unique print head geometry allowing excess sheath fluid to be separated from the print flow stream for recycling/reuse. Fluid flow models suggest that more than 81 percent of the sheath fluid can be removed without affecting the print stream. Further development and optimization is required to demonstrate this capabilitymore » in operation. Print results using two-fluid hydrodynamic focusing yielded a 30 micrometers wide by 0.5 micrometers tall line that suggests that the cross-section of the printed feature from the print head was approximately 2 micrometers in diameter. Printing results also demonstrated that complete removal of the sheath fluid is not necessary for all material systems. The two-fluid printing technology could enable printing of insulated conductors and clad optical interconnects. Further development of this concept should be pursued.« less

Persistent Latent Tuberculosis Reactivation Risk in United States Immigrants

PubMed Central

Painter, John; Parker, Matthew; Lowenthal, Phillip; Flood, Jennifer; Fu, Yunxin; Asis, Redentor; Reves, Randall

2014-01-01

Rationale: Current guidelines limit latent tuberculosis infection (LTBI) evaluation to persons in the United States less than or equal to 5 years based on the assumption that high TB rates among recent entrants are attributable to high LTBI reactivation risk, which declines over time. We hypothesized that high postarrival TB rates may instead be caused by imported active TB. Objectives: Estimate reactivation and imported TB in an immigrant cohort. Methods: We linked preimmigration records from a cohort of California-bound Filipino immigrants during 2001–2010 with subsequent TB reports. TB was likely LTBI reactivation if the immigrant had no evidence of active TB at preimmigration examination, likely imported if preimmigration radiograph was abnormal and TB was reported less than or equal to 6 months after arrival, and likely reactivation of inactive TB if radiograph was abnormal but TB was reported more than 6 months after arrival. Measurements and Main Results: Among 123,114 immigrants, 793 TB cases were reported. Within 1 year of preimmigration examination, 85% of TB was imported; 6 and 9% were reactivation of LTBI and inactive TB, respectively. Conversely, during Years 2–9 after U.S. entry, 76 and 24% were reactivation of LTBI and inactive TB, respectively. The rate of LTBI reactivation (32 per 100,000) did not decline during Years 1–9. Conclusions: High postarrival TB rates were caused by detection of imported TB through active postarrival surveillance. Among immigrants without active TB at baseline, reported TB did not decline over 9 years, indicating sustained high risk of LTBI reactivation. Revised guidelines should support LTBI screening and treatment more than 5 years after U.S. arrival. PMID:24308495

Viscous fingering with partially miscible fluids

NASA Astrophysics Data System (ADS)

Fu, Xiaojing; Cueto-Felgueroso, Luis; Juanes, Ruben

2017-10-01

Viscous fingering—the fluid-mechanical instability that takes place when a low-viscosity fluid displaces a high-viscosity fluid—has traditionally been studied under either fully miscible or fully immiscible fluid systems. Here we study the impact of partial miscibility (a common occurrence in practice) on the fingering dynamics. Through a careful design of the thermodynamic free energy of a binary mixture, we develop a phase-field model of fluid-fluid displacements in a Hele-Shaw cell for the general case in which the two fluids have limited (but nonzero) solubility into one another. We show, by means of high-resolution numerical simulations, that partial miscibility exerts a powerful control on the degree of fingering: fluid dissolution hinders fingering while fluid exsolution enhances fingering. We also show that, as a result of the interplay between compositional exchange and the hydrodynamic pattern-forming process, stronger fingering promotes the system to approach thermodynamic equilibrium more quickly.

Ultra-high performance supercritical fluid chromatography of lignin-derived phenols from alkaline cupric oxide oxidation.

PubMed

Sun, Mingzhe; Lidén, Gunnar; Sandahl, Margareta; Turner, Charlotta

2016-08-01

Traditional chromatographic methods for the analysis of lignin-derived phenolic compounds in environmental samples are generally time consuming. In this work, an ultra-high performance supercritical fluid chromatography method with a diode array detector for the analysis of major lignin-derived phenolic compounds produced by alkaline cupric oxide oxidation was developed. In an analysis of a collection of 11 representative monomeric lignin phenolic compounds, all compounds were clearly separated within 6 min with excellent peak shapes, with a limit of detection of 0.5-2.5 μM, a limit of quantification of 2.5-5.0 μM, and a dynamic range of 5.0-2.0 mM (R(2) > 0.997). The new ultra-high performance supercritical fluid chromatography method was also applied for the qualitative and quantitative analysis of lignin-derived phenolic compounds obtained upon alkaline cupric oxide oxidation of a commercial humic acid. Ten out of the previous eleven model compounds could be quantified in the oxidized humic acid sample. The high separation power and short analysis time obtained demonstrate for the first time that supercritical fluid chromatography is a fast and reliable technique for the analysis of lignin-derived phenols in complex environmental samples. © 2016 The Authors, Journal of Separation Science Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Contrasting fault fluids along high-angle faults: a case study from Southern Apennines (Italy)

NASA Astrophysics Data System (ADS)

Sinisi, Rosa; Petrullo, Angela Vita; Agosta, Fabrizio; Paternoster, Michele; Belviso, Claudia; Grassa, Fausto

2016-10-01

This work focuses on two fault-controlled deposits, the Atella and Rapolla travertines, which are associated with high-angle extensional faults of the Bradano Trough, southern Apennines (Italy). The Atella travertine is along a NW-SE striking, deep-seated extensional fault, already described in literature, which crosscuts both Apulian carbonates and the overlying foredeep basin infill. The Rapolla travertine is on top of a NE-SW striking, shallow-seated fault, here described for the first time, which is interpreted as a tear fault associated with a shallow thrust displacing only the foredeep basin infill. The results of structural, sedimentological, mineralogical, and C and O isotope analyses are here reported and discussed to assess the provenance of mineralizing fluids, and to evaluate the control exerted by the aforementioned extensional faults on deep, mantle-derived and shallow, meteoric fluids. Sedimentological analysis is consistent with five lithofacies in the studied travertines, which likely formed in a typical lacustrine depositional environment. Mineralogical analysis show that travertines mainly consist of calcite, and minor quartz, feldspar and clay minerals, indicative of a terrigenous supply during travertine precipitation. The isotope signature of the two studied travertines shows different provenance for the mineralizing fluids. At the Atella site, the δ13CPDB values range between + 5.2 and + 5.7‰ and the δ18OPDB values between - 9.0 and - 7.3‰, which are consistent with a mantle-derived CO2 component in the fluid. In contrast, at the Rapolla site the δ13CPDB values vary from - 2.7 to + 1.5‰ and the δ18OPDB values from - 6.8 to - 5.4‰, suggesting a mixed CO2 source with both biogenic-derived and mantle-derived fluids. The results of structural analyses conducted along the footwall damage zone of the fault exposed at the Rapolla site, show that the whole damage zone, in which fractures and joints likely channeled the mixed fluids, acted

The reactive element effect of yttrium and yttrium silicon on high temperature oxidation of NiCrAl coating

NASA Astrophysics Data System (ADS)

Ramandhany, S.; Sugiarti, E.; Desiati, R. D.; Martides, E.; Junianto, E.; Prawara, B.; Sukarto, A.; Tjahjono, A.

2018-03-01

The microstructure formed on the bond coat affects the oxidation resistance, particularly the formation of a protective oxide layer. The adhesion of bond coat and TGO increased significantly by addition of reactive element. In the present work, the effect of yttrium and yttrium silicon as reactive element (RE) on NiCrAl coating was investigated. The NiCrAl (without RE) and NiCrAlX (X:Y or YSi) bond coating were deposited on Hastelloy C-276 substrate by High Velocity Oxygen Fuel (HVOF) method. Isothermal oxidation was carried out at 1000 °C for 100 hours. The results showed that the addition of RE could prevent the breakaway oxidation. Therefore, the coating with reactive element were more protective against high temperature oxidation. Furthermore, the oxidation rate of NiCrAlY coating was lower than NiCrAlYSi coating with the total mass change was ±2.394 mg/cm2 after 100 hours of oxidation. The thickness of oxide scale was approximately 1.18 μm consisting of duplex oxide scale of spinel NiCr2O4 in outer scale and protective α-Al2O3 in inner scale.

Relationship Between Far Field Stresses, Fluid Flow and High-Pressure Deserpentinization in Subducting Slabs: a Case Study From the Almirez Ultramafic Massif

NASA Astrophysics Data System (ADS)

Dilissen, Nicole; Hidas, Károly; Garrido, Carlos J.; López Sánchez-Vizcaíno, Vicente; Kahl, Wolf-Achim; Padrón-Navarta, José Alberto; Jesús Román-Alpiste, Manuel

2017-04-01

press). Fluid escape from subduction zones controlled by channel-forming reactive porosity. Nature Geoscience. 4. Chen, P.-F., Bina, C.R., Okal, E.A., 2004. A global survey of stress orientations in subducting slabs as revealed by intermediate-depth earthquakes. Geophysical Journal International 159, 721-733. 5. Padrón-Navarta, J.A., Tommasi, A., Garrido, C.J., López Sánchez-Vizcaíno, V., 2012. Plastic deformation and development of antigorite crystal preferred orientation in high-pressure serpentinites. Earth and Planetary Science Letters 349-350, 75-86. doi: 10.1016/j.epsl.2012.06.049 6. Kahl, W.-A., Hidas, K., Dilissen, N., Garrido, C.J., López-Sánchez Vizcaíno, V., Román-Alpiste, M.J. 2017. Reconstruction of the 3-D shape and crystal preferred orientation of olivine: a combined µ-CT and EBSD-SEM approach. Geophysical Research Abstracts 19, EGU2017-8061. Funding: Research leading to these results was funded by the EU-FP7 Marie Curie Initial Training Network ZIP - Zooming in between plates.

A Preliminary Experimental Examination of Worldview Verification, Perceived Racism, and Stress Reactivity in African Americans

PubMed Central

Lucas, Todd; Lumley, Mark A.; Flack, John M.; Wegner, Rhiana; Pierce, Jennifer; Goetz, Stefan

2016-01-01

Objective According to worldview verification theory, inconsistencies between lived experiences and worldviews are psychologically threatening. These inconsistencies may be key determinants of stress processes that influence cardiovascular health disparities. This preliminary examination considers how experiencing injustice can affect perceived racism and biological stress reactivity among African Americans. Guided by worldview verification theory, it was hypothesized that responses to receiving an unfair outcome would be moderated by fairness of the accompanying decision process, and that this effect would further depend on the consistency of the decision process with preexisting justice beliefs. Method A sample of 118 healthy African American adults completed baseline measures of justice beliefs, followed by a laboratory-based social-evaluative stressor task. Two randomized fairness manipulations were implemented during the task: participants were given either high or low levels of distributive (outcome) and procedural (decision process) justice. Glucocorticoid (cortisol) and inflammatory (C-reactive protein) biological responses were measured in oral fluids, and attributions of racism were also measured. Results The hypothesized 3-way interaction was generally obtained. Among African Americans with a strong belief in justice, perceived racism, cortisol and C-reactive protein responses to low distributive justice were higher when procedural justice was low. Among African Americans with a weak belief in justice however, these responses were higher when a low level of distributive justice was coupled with high procedural justice. Conclusions Biological and psychological processes that contribute to cardiovascular health disparities are affected by consistency between individual-level and contextual justice factors. PMID:27018728

A preliminary experimental examination of worldview verification, perceived racism, and stress reactivity in African Americans.

PubMed

Lucas, Todd; Lumley, Mark A; Flack, John M; Wegner, Rhiana; Pierce, Jennifer; Goetz, Stefan

2016-04-01

According to worldview verification theory, inconsistencies between lived experiences and worldviews are psychologically threatening. These inconsistencies may be key determinants of stress processes that influence cardiovascular health disparities. This preliminary examination considers how experiencing injustice can affect perceived racism and biological stress reactivity among African Americans. Guided by worldview verification theory, it was hypothesized that responses to receiving an unfair outcome would be moderated by fairness of the accompanying decision process, and that this effect would further depend on the consistency of the decision process with preexisting justice beliefs. A sample of 118 healthy African American adults completed baseline measures of justice beliefs, followed by a laboratory-based social-evaluative stressor task. Two randomized fairness manipulations were implemented during the task: participants were given either high or low levels of distributive (outcome) and procedural (decision process) justice. Glucocorticoid (cortisol) and inflammatory (C-reactive protein) biological responses were measured in oral fluids, and attributions of racism were also measured. The hypothesized 3-way interaction was generally obtained. Among African Americans with a strong belief in justice, perceived racism, cortisol, and C-reactive protein responses to low distributive justice were higher when procedural justice was low. Among African Americans with a weak belief in justice however, these responses were higher when a low level of distributive justice was coupled with high procedural justice. Biological and psychological processes that contribute to cardiovascular health disparities are affected by consistency between individual-level and contextual justice factors. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Synovial fluid cytology in experimental acute canine monocytic ehrlichiosis (Ehrlichia canis).

PubMed

Theodorou, Konstantina; Leontides, Leonidas; Siarkou, Victoria I; Petanides, Theodoros; Tsafas, Konstantinos; Harrus, Shimon; Mylonakis, Mathios E

2015-05-15

Evidence-based information of a cause-and-effect relationship between Ehrlichia canis infection and polyarthritis in naturally- or experimentally-infected dogs is currently lacking. The aim of this prospective study was to investigate whether synovial fluid cytological evidence of arthritis could be documented in dogs with acute monocytic ehrlichiosis. Direct synovial fluid cytology smears from eight Beagle dogs experimentally infected with E. canis were examined prior to, and on 21, 35 and 63 days post-inoculation. The cytological variables assessed included cellularity, percentages of mononuclear cells and neutrophils, macrophage reactivity and evidence of E. canis morulae. The median cellularity and percentages of mononuclear cells and neutrophils prior to inoculation did not differ when compared to post-inoculation cytological evaluation. Increased cellularity, E. canis morulae or cytological evidence of arthritis or macrophage reactivity were not observed throughout the course of the study. In the present study, no cytological evidence of arthritis was found in dogs with experimental acute canine monocytic ehrlichiosis, suggesting that E. canis infection should be considered a rather uncommon cause of arthritis in dogs. Copyright © 2015 Elsevier B.V. All rights reserved.

Treatment effect, adherence, and safety of high fluid intake for the prevention of incident and recurrent kidney stones: a systematic review and meta-analysis.

PubMed

Cheungpasitporn, Wisit; Rossetti, Sandro; Friend, Keith; Erickson, Stephen B; Lieske, John C

2016-04-01

The objective of this systematic review and meta-analysis were to evaluate the effectiveness of high fluid intake for the prevention of incident and recurrent kidney stones, as well as its adherence and safety. A literature search was performed encompassing 1980 through July 2014. Studies that reported relative risks, odds ratios, or hazard ratios comparing the risk of kidney stone events in patients with high vs inadequate fluid intake were included. Pooled risk ratios (RRs) and 95 % confidence intervals (CIs) were calculated using a random-effect, generic inverse variance method. Nine studies [2 randomized controlled trials (RCTs) with 269 patients; 7 observational studies with 273,685 individuals] were included in the meta-analysis. Pooled RRs of kidney stones in individuals with high-fluid intake were 0.40 (95 % CI 0.20-0.79) and 0.49 (0.34-0.71) in RCTs and observational studies, respectively. High fluid intake was significantly associated with reduced risk of recurrent kidney stones: RRs 0.40 (95 % CI 0.20-0.79) and 0.20 (0.09-0.44) in RCTs and observational studies, respectively. Adherence and safety data on high fluid intake treatment were limited; 1 RCT reported no withdrawals due to adverse events. This analysis demonstrated a significantly reduced risk of incident kidney stones among individuals with high fluid consumption. High fluid consumption also reduced the risk of recurrent kidney stones. Furthermore, the magnitude of risk reduction was high. Although increased water intake appears to be safe, future studies on its safety in patients with high risk of volume overload or hyponatremia may be indicated.

Mesoscopic simulations of shock-to-detonation transition in reactive liquid high explosive

NASA Astrophysics Data System (ADS)

Maillet, J. B.; Bourasseau, E.; Desbiens, N.; Vallverdu, G.; Stoltz, G.

2011-12-01

An extension of the model described in a previous work (see Maillet J. B. et al., EPL, 78 (2007) 68001) based on Dissipative Particle Dynamics is presented and applied to a liquid high explosive (HE), with thermodynamic properties mimicking those of liquid nitromethane. Large scale nonequilibrium simulations of reacting liquid HE with model kinetic under sustained shock conditions allow a better understanding of the shock-to-detonation transition in homogeneous explosives. Moreover, the propagation of the reactive wave appears discontinuous since ignition points in the shocked material can be activated by the compressive waves emitted from the onset of chemical reactions.

Rock-Fluid Interactions Under Stress: How Rock Microstructure Controls The Evolution of Porosity and Permeability

NASA Astrophysics Data System (ADS)

Vanorio, T.

2016-12-01

Monitoring chemo-mechanical processes geophysically — e.g., fluid disposal or storage, thermal and chemical stimulation of reservoirs, or natural fluids simply entering a new system in the subsurface— raises numerous concerns because of the likelihood of fluid-rock chemical interactions and our limited ability to decipher the geophysical signature of coupled processes. One of the missing links is coupling the evolution of porosity, permeability, and velocity of rocks together with reactive transport, since rocks deform and their microstructure evolves, as a result of chemical reactions under stress. This study describes recent advances in rock-physics experiments to understand the effects of dissolution-induced compaction on acoustic velocity, porosity, and permeability. Data observation includes time-lapse experiments and imaging tracking transport and elastic properties, the rock microstructure, and the pH and chemical composition of the fluid permeating the rock. Results show that the removal of high surface area, mineral phases such as microcrystalline calcite and clay appears to be mostly responsible for dissolution-induced compaction. Nevertheless, it is the original rock microstructure and its response to stress that ultimately defines how solution-transfer and rock compaction feed back upon each other. This work has a dual aim: understanding the mechanisms underlying permanent modifications to the rock microstructure and providing a richer set of experimental information to inform the formulation of new simulations and rock modeling.

Reactive Power Compensation Method Considering Minimum Effective Reactive Power Reserve

NASA Astrophysics Data System (ADS)

Gong, Yiyu; Zhang, Kai; Pu, Zhang; Li, Xuenan; Zuo, Xianghong; Zhen, Jiao; Sudan, Teng

2017-05-01

According to the calculation model of minimum generator reactive power reserve of power system voltage stability under the premise of the guarantee, the reactive power management system with reactive power compensation combined generator, the formation of a multi-objective optimization problem, propose a reactive power reserve is considered the minimum generator reactive power compensation optimization method. This method through the improvement of the objective function and constraint conditions, when the system load growth, relying solely on reactive power generation system can not meet the requirement of safe operation, increase the reactive power reserve to solve the problem of minimum generator reactive power compensation in the case of load node.

Chemical Reactivity Test (CRT)

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

Zaka, F.

The Chemical Reactivity Test (CRT) is used to determine the thermal stability of High Explosives (HEs) and chemical compatibility between (HEs) and alien materials. The CRT is one of the small-scale safety tests performed on HE at the High Explosives Applications Facility (HEAF).

FRACTURING FLUID CHARACTERIZATION FACILITY

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

Subhash Shah

2000-08-01

Hydraulic fracturing technology has been successfully applied for well stimulation of low and high permeability reservoirs for numerous years. Treatment optimization and improved economics have always been the key to the success and it is more so when the reservoirs under consideration are marginal. Fluids are widely used for the stimulation of wells. The Fracturing Fluid Characterization Facility (FFCF) has been established to provide the accurate prediction of the behavior of complex fracturing fluids under downhole conditions. The primary focus of the facility is to provide valuable insight into the various mechanisms that govern the flow of fracturing fluids andmore » slurries through hydraulically created fractures. During the time between September 30, 1992, and March 31, 2000, the research efforts were devoted to the areas of fluid rheology, proppant transport, proppant flowback, dynamic fluid loss, perforation pressure losses, and frictional pressure losses. In this regard, a unique above-the-ground fracture simulator was designed and constructed at the FFCF, labeled ''The High Pressure Simulator'' (HPS). The FFCF is now available to industry for characterizing and understanding the behavior of complex fluid systems. To better reflect and encompass the broad spectrum of the petroleum industry, the FFCF now operates under a new name of ''The Well Construction Technology Center'' (WCTC). This report documents the summary of the activities performed during 1992-2000 at the FFCF.« less

Influence of nitrogen admixture to argon on the ion energy distribution in reactive high power pulsed magnetron sputtering of chromium

NASA Astrophysics Data System (ADS)

Breilmann, W.; Maszl, C.; Hecimovic, A.; von Keudell, A.

2017-04-01

Reactive high power impulse magnetron sputtering (HiPIMS) of metals is of paramount importance for the deposition of various oxides, nitrides and carbides. The addition of a reactive gas such as nitrogen to an argon HiPIMS plasma with a metal target allows the formation of the corresponding metal nitride on the substrate. The addition of a reactive gas introduces new dynamics into the plasma process, such as hysteresis, target poisoning and the rarefaction of two different plasma gases. We investigate the dynamics for the deposition of chromium nitride by a reactive HiPIMS plasma using energy- and time-resolved ion mass spectrometry, fast camera measurements and temporal and spatially resolved optical emission spectroscopy. It is shown that the addition of nitrogen to the argon plasma gas significantly changes the appearance of the localized ionization zones, the so-called spokes, in HiPIMS plasmas. In addition, a very strong modulation of the metal ion flux within each HiPIMS pulse is observed, with the metal ion flux being strongly suppressed and the nitrogen molecular ion flux being strongly enhanced in the high current phase of the pulse. This behavior is explained by a stronger return effect of the sputtered metal ions in the dense plasma above the racetrack. This is best observed in a pure nitrogen plasma, because the ionization zones are mostly confined, implying a very high local plasma density and consequently also an efficient scattering process.

Fluid cognitive ability is associated with greater exposure and smaller reactions to daily stressors.

PubMed

Stawski, Robert S; Almeida, David M; Lachman, Margie E; Tun, Patricia A; Rosnick, Christopher B

2010-06-01

The authors of this study investigated whether fluid cognitive ability predicts exposure and emotional reactivity to daily stressors. A national sample of adults from the Midlife in the United States study and the National Study of Daily Experiences (N = 1,202) who had a mean age of 57 years (SD = 12; 56% women, 44% men) completed positive and negative mood reports as well as a stressor diary on 8 consecutive evenings via telephone. Participants also completed a telephone-based battery of tests measuring fluid cognitive ability. Higher levels of fluid cognitive ability were associated with greater exposure to work- and home-related overload stressors. Possessing higher levels of fluid cognitive ability was associated with smaller stressor-related increases in negative mood, primarily for interpersonal tensions and network stressors, and smaller stressor-related decreases in positive mood for interpersonal tensions. Furthermore, fluid cognitive ability was unrelated to subjective severity ratings of the stressors reported. Discussion focuses on the role of fluid cognitive ability in daily stress processes. (c) 2010 APA, all rights reserved).

Evaluation of Advanced Reactive Surface Area Estimates for Improved Prediction of Mineral Reaction Rates in Porous Media

NASA Astrophysics Data System (ADS)

Beckingham, L. E.; Mitnick, E. H.; Zhang, S.; Voltolini, M.; Yang, L.; Steefel, C. I.; Swift, A.; Cole, D. R.; Sheets, J.; Kneafsey, T. J.; Landrot, G.; Anovitz, L. M.; Mito, S.; Xue, Z.; Ajo Franklin, J. B.; DePaolo, D.

2015-12-01

CO2 sequestration in deep sedimentary formations is a promising means of reducing atmospheric CO2 emissions but the rate and extent of mineral trapping remains difficult to predict. Reactive transport models provide predictions of mineral trapping based on laboratory mineral reaction rates, which have been shown to have large discrepancies with field rates. This, in part, may be due to poor quantification of mineral reactive surface area in natural porous media. Common estimates of mineral reactive surface area are ad hoc and typically based on grain size, adjusted several orders of magnitude to account for surface roughness and reactivity. This results in orders of magnitude discrepancies in estimated surface areas that directly translate into orders of magnitude discrepancies in model predictions. Additionally, natural systems can be highly heterogeneous and contain abundant nano- and micro-porosity, which can limit connected porosity and access to mineral surfaces. In this study, mineral-specific accessible surface areas are computed for a sample from the reservoir formation at the Nagaoka pilot CO2 injection site (Japan). Accessible mineral surface areas are determined from a multi-scale image analysis including X-ray microCT, SEM QEMSCAN, XRD, SANS, and SEM-FIB. Powder and flow-through column laboratory experiments are performed and the evolution of solutes in the aqueous phase is tracked. Continuum-scale reactive transport models are used to evaluate the impact of reactive surface area on predictions of experimental reaction rates. Evaluated reactive surface areas include geometric and specific surface areas (eg. BET) in addition to their reactive-site weighted counterparts. The most accurate predictions of observed powder mineral dissolution rates were obtained through use of grain-size specific surface areas computed from a BET-based correlation. Effectively, this surface area reflects the grain-fluid contact area, or accessible surface area, in the powder

Analysis of high injection pressure and ambient temperature on biodiesel spray characteristics using computational fluid dynamics

NASA Astrophysics Data System (ADS)

Hashim, Akasha; Khalid, Amir; Jaat, Norrizam; Sapit, Azwan; Razali, Azahari; Nizam, Akmal

2017-09-01

Efficiency of combustion engines are highly affected by the formation of air-fuel mixture prior to ignition and combustion process. This research investigate the mixture formation and spray characteristics of biodiesel blends under variant in high ambient and injection conditions using Computational Fluid Dynamics (CFD). The spray characteristics such as spray penetration length, spray angle and fluid flow were observe under various operating conditions. Results show that increase in injection pressure increases the spray penetration length for both biodiesel and diesel. Results also indicate that higher spray angle of biodiesel can be seen as the injection pressure increases. This study concludes that spray characteristics of biodiesel blend is greatly affected by the injection and ambient conditions.

Emotional Reactivity, Behavior Problems, and Social Adjustment at School Entry in a High-risk Sample.

PubMed

Kalvin, Carla B; Bierman, Karen L; Gatzke-Kopp, Lisa M

2016-11-01

Prior research suggests that heightened emotional reactivity to emotionally distressing stimuli may be associated with elevated internalizing and externalizing behaviors, and contribute to impaired social functioning. These links were explored in a sample of 169 economically-disadvantaged kindergarteners (66 % male; 68 % African American, 22 % Hispanic, 10 % Caucasian) oversampled for elevated aggression. Physiological measures of emotional reactivity (respiratory sinus arrhythmia [RSA], heart rate [HR], and cardiac pre-ejection period [PEP]) were collected, and teachers and peers provided ratings of externalizing and internalizing behavior, prosocial competence, and peer rejection. RSA withdrawal, HR reactivity, and PEP shortening (indicating increased arousal) were correlated with reduced prosocial competence, and RSA withdrawal and HR reactivity were correlated with elevated internalizing problems. HR reactivity was also correlated with elevated externalizing problems and peer rejection. Linear regressions controlling for age, sex, race, verbal proficiency, and resting physiology showed that HR reactivity explained unique variance in both teacher-rated prosocial competence and peer rejection, and contributed indirectly to these outcomes through pathways mediated by internalizing and externalizing problems. A trend also emerged for the unique contribution of PEP reactivity to peer-rated prosocial competence. These findings support the contribution of emotional reactivity to behavior problems and social adjustment among children living in disadvantaged urban contexts, and further suggest that elevated reactivity may confer risk for social difficulties in ways that overlap only partially with internalizing and externalizing behavior problems.

Emotional Reactivity, Behavior Problems, and Social Adjustment at School Entry in a High-risk Sample

PubMed Central

Kalvin, Carla B.; Bierman, Karen L.; Gatzke-Kopp, Lisa M.

2016-01-01

Prior research suggests that heightened emotional reactivity to emotionally distressing stimuli may be associated with elevated internalizing and externalizing behaviors, and contribute to impaired social functioning. These links were explored in a sample of 169 economically-disadvantaged kindergarteners (66 % male; 68 % African American, 22 % Hispanic, 10 % Caucasian) oversampled for elevated aggression. Physiological measures of emotional reactivity (respiratory sinus arrhythmia [RSA], heart rate [HR], and cardiac pre-ejection period [PEP]) were collected, and teachers and peers provided ratings of externalizing and internalizing behavior, prosocial competence, and peer rejection. RSA withdrawal, HR reactivity, and PEP shortening (indicating increased arousal) were correlated with reduced prosocial competence, and RSA withdrawal and HR reactivity were correlated with elevated internalizing problems. HR reactivity was also correlated with elevated externalizing problems and peer rejection. Linear regressions controlling for age, sex, race, verbal proficiency, and resting physiology showed that HR reactivity explained unique variance in both teacher-rated prosocial competence and peer rejection, and contributed indirectly to these outcomes through pathways mediated by internalizing and externalizing problems. A trend also emerged for the unique contribution of PEP reactivity to peer-rated prosocial competence. These findings support the contribution of emotional reactivity to behavior problems and social adjustment among children living in disadvantaged urban contexts, and further suggest that elevated reactivity may confer risk for social difficulties in ways that overlap only partially with internalizing and externalizing behavior problems. PMID:26943804

Focusing Fluids towards the Arc: the Role of Rehydration Reactions and Rheology

NASA Astrophysics Data System (ADS)

Wilson, C. R.; Spiegelman, M. W.; Van Keken, P. E.; Hacker, B. R.

2015-12-01

Aqueous fluids released from the down-going slab in subduction zones are generally thought to be the cause of arc volcanism. However there is a significant discrepancy between the consistent location of the volcanic front with respect to intermediate depth earthquakes (e.g. 100+/-40 km; England et al., GJI, 2004, Syracuse & Abers, G-cubed, 2006) and the large depth range over which dehydration reactions are predicted to occur in the slab (e.g. 80-250 km; van Keken et al., JGR, 2011).By coupling the fluid flow to the solid rheology through compaction pressure, recent numerical models (Wilson et al., EPSL, 2014) demonstrated a number of focusing mechanisms that can be invoked to explain this apparent discrepancy. Most notable among these were permeability channels within the slab. These were shown to be highly effective in transporting fluid from deeper fluid sources along the slab towards the shallowest source. In the presence of these channels the majority of the fluid is released into the mantle wedge far shallower and closer to the arc than it was originally generated.While observations consistent with free fluids in the slab have been reported (e.g. Shiina et al., GRL, 2013), it is possible that changing the reactivity and rheology of the slab can change the efficiency of in-slab transport (e.g. Wada et al., EPSL, 2012, Faccenda et al., G3, 2012). We present a series of simplified model problems of fluid flow within the slab and mantle wedge demonstrating the potential effect of these processes on fluid flux. In particular, pseudo-1D models show that if fluids can efficiently rehydrate slab minerals, then these reactions can shut down fluid pathways within the slab, resulting in deeper release of fluid into the mantle wedge. We will expand these results to consider the effects of rehydration in 2-D calculations. In addition, our previous models have considered only the simplest rheologies and geometries for the slab. We will also discuss new results that

Atomistic Simulations of Chemical Reactivity of TATB Under Thermal and Shock Conditions

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

Manaa, M R; Reed, E J; Fried, L E

2009-09-23

reactivity of TATB well into the formation of several stable gas products, such as H{sub 2}O, N{sub 2}, and CO{sub 2}. Although complex chemical transformations are occurring continuously in the dynamical, high temperature, reactive environment of our simulations, a simple overall scheme for the decomposition of TATB emerges: Water is the earliest decomposition products to form, followed by a polymerization (or condensation) process in which several TATB remaining fragments are joined together, initiating the early step in the formation of high-nitrogen clusters, along with stable products such as N{sub 2} and CO{sub 2}. Remarkably, these clusters with high concentration of carbon and nitrogen (and little oxygen) remain dynamically stable for the remaining period of the simulations. Our simulations, thus, reveal a hitherto unidentified region of high concentrations of nitrogen-rich heterocyclic clusters in reacting TATB, whose persistence impede further reactivity towards final products of fluid N{sub 2} and solid carbon. These simulations also predict significant populations of charged species such as NCO{sup -}, H{sup +}, OH{sup -}, H{sub 3}O{sup +}, and O{sup -2}, the first such observation in a reacting explosive. Finally, A reduced four steps, global reaction mechanism with Arrhenius kinetic rates for the decomposition of TATB, along with comparative Cheetah decomposition kinetics at various temperatures has been constructed and will be discussed.« less

Affinity adsorption of glucose degradation products improves the biocompatibility of conventional peritoneal dialysis fluid.

PubMed

Ishikawa, Naoyoshi; Miyata, Toshio; Ueda, Yasuhiko; Inagi, Reiko; Izuhara, Yuko; Yuzawa, Hiroko; Onogi, Hiroshi; Nishina, Makoto; Nangaku, Masaomi; Van Ypersele De Strihou, Charles; Kurokawa, Kiyoshi

2003-01-01

Reactive carbonyl compounds (RCOs) present in peritoneal dialysis (PD) fluid have been incriminated in the progressive deterioration of the peritoneal membrane in long-term PD patients. They are initially present in fresh conventional heat-sterilized glucose PD fluid and are supplemented during dwell time by the diffusion of blood RCOs within the peritoneal cavity. In the present study, RCO entrapping agents were immobilized on affinity beads to adsorb RCOs both in fresh PD fluid and in PD effluent. The RCO trapping potential of various compounds was assessed in vitro first by dissolving them in the tested fluid and subsequently after coupling with either epoxy- or amino-beads. The tested fluids include fresh heat-sterilized glucose and non-glucose PD fluids, and PD effluent. Their RCOs contents, that is, glyoxal (GO), methylglyoxal (MGO), 3-deoxyglucosone (3-DG), formaldehyde, 5-hydroxymethylfuraldehyde, acetaldehyde, and 2-furaldehyde were monitored by reverse-phase high-pressure liquid chromatography. The biocompatibility of PD fluid was assessed by a cytotoxic assay with either human epidermoid cell line A431 cells or with primary cultured human peritoneal mesothelial cells. Among the tested RCO entrapping agents, hydrazine coupled to epoxy-beads proved the most efficient. It lowered the concentrations of three dicarbonyl compounds (GO, MGO, and 3-DG) and those of aldehydes present in fresh heat-sterilized glucose PD fluid toward the low levels observed in filter-sterilized glucose PD fluid. It did not change the glucose and electrolytes concentration of the PD fluid but raised its pH from 5.2 to 5.9. Hydrazine-coupled epoxy-bead also lowered the PD effluent content of total RCOs, measured by the 2,4-dinitrophenylhydrazone (DNPH) method. The cytotoxicity of heat-sterilized PD fluid incubated with hydrazine-coupled epoxy-beads was decreased to the level observed in filter-sterilized PD fluid as the result of the raised pH and the lowered RCOs levels. Hydrazine

Comparison of oral fluid collection methods for the molecular detection of hepatitis B virus.

PubMed

Portilho, M M; Mendonça, Acf; Marques, V A; Nabuco, L C; Villela-Nogueira, C A; Ivantes, Cap; Lewis-Ximenez, L L; Lampe, E; Villar, L M

2017-11-01

This study aims to compare the efficiency of four oral fluid collection methods (Salivette, FTA Card, spitting and DNA-Sal) to detect HBV DNA by qualitative PCR. Seventy-four individuals (32 HBV reactive and 42 with no HBV markers) donated serum and oral fluid. In-house qualitative PCR to detect HBV was used for both samples and commercial quantitative PCR for serum. HBV DNA was detected in all serum samples from HBV-infected individuals, and it was not detected in control group. HBV DNA from HBV group was detected in 17 samples collected with Salivette device, 16 samples collected by FTA Card device, 16 samples collected from spitting and 13 samples collected by DNA-Sal device. Samples that corresponded to a higher viral load in their paired serum sample could be detected using all oral fluid collection methods, but Salivette collection device yielded the largest numbers of positive samples and had a wide range of viral load that was detected. It was possible to detect HBV DNA using all devices tested, but higher number of positive samples was observed when samples were collected using Salivette device, which shows high concordance to viral load observed in the paired serum samples. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved.

Communication and social interaction anxiety enhance interleukin-1 beta and cortisol reactivity during high-stakes public speaking.

PubMed

Auer, Brandon J; Calvi, Jessica L; Jordan, Nicolas M; Schrader, David; Byrd-Craven, Jennifer

2018-08-01

Worry or fear related to speaking in front of others, or more broadly, communicating and interacting with others, is common. At elevated levels, however, it may contribute to heightened stress reactivity during acute speaking challenges. The purpose of this study was to examine multi-system physiological stress reactivity in the context of high-stakes public speaking while considering the impact of hypothesized individual difference risk factors. University student participants (n = 95) delivering speeches as a heavily-weighted component of their final grade had saliva samples collected immediately prior to speaking, immediately after, and 20 min after speech completion. Saliva samples were assayed for alpha amylase (sAA), cortisol, and interleukin-1 beta (IL-1β). Self-reported communication anxiety, social interaction anxiety, rejection sensitivity, and sex were assessed as risk factors for heightened stress reactivity. Salivary sAA, cortisol, and IL-1β significantly changed following speech delivery. Multivariate analyses demonstrated that elevated levels of self-reported communication anxiety and social interaction anxiety were independently associated with increased cortisol and IL-1β responses and combined to enhance HPA axis and inflammatory cytokine activity further (i.e., cortisol and IL-1β AUC I ). Sex and rejection sensitivity were unrelated to physiological stress reactivity. These findings suggest that individuals with elevated communication and interaction fears may be at increased risk of heightened neuroendocrine and inflammatory responses following exposure to acute social stressors. Both types of anxiety may combine to increase physiological reactivity further, with unknown, though likely insalubrious, health consequences over time. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterizing Reactive Flow Paths in Fractured Cement

NASA Astrophysics Data System (ADS)

Wenning, Q. C.; Huerta, N. J.; Hesse, M. A.; Bryant, S. L.

2011-12-01

Geologic carbon sequestration can be a viable method for reducing anthropogenic CO2 flux into the atmosphere. However, the technology must be economically feasible and pose acceptable risk to stakeholders. One key risk is CO2 leakage out of the storage reservoir. Potential driving forces for leakage are the overpressure due to CO2 injection and the buoyancy of free phase CO2. Potential hazards of leakage are contamination of Underground Sources of Drinking Water or the atmosphere and would be deemed an unacceptable risk. Wells potentially provide a fast path for leakage from the reservoir. While the well's cement casing is reactive with CO2 and CO2-saturated brine, the low cement matrix permeability and slow diffusion rate make it unlikely that CO2 will escape through a properly constructed wellbore. However, highly permeable fractures with micrometer scale apertures can occur in cement casings. Reactions that occur in the flow in these fractures can either be self-limiting or self-enhancing. Therefore, understanding the reactive flow is critical to understanding of leakage evolution through these fractures. The goal of our work is to characterize the modification of the flow paths in the fracture due to reaction with acidic brine. With this aim we have characterized both the initial flow path of un-reactive flow and the final flow path after introduction of low-pH acid along the same fracture. Class H cement cores 3-6 cm in length and 2.5 cm diameter are created and a single natural and unique fracture is produced in each core using the Brazilian method. Our experimental fluid is injected at a constant rate into the cement core housed in a Hassler Cell under confining pressure. A solution of red dye and deionized water is pumped through the fracture to stain the un-reactive flow paths. Deionized water is then pumped through the core to limit diffusion of the dye into non-flowing portions of the fracture. After staining the initial flow path, low pH water due to

Oligoclonal bands in multiple sclerosis reactive against two herpesviruses and association with magnetic resonance imaging findings

PubMed Central

Virtanen, JO; Wohler, J; Fenton, K; Reich, DS; Jacobson, S

2016-01-01

Background Two human herpesviruses, human herpesvirus 6 (HHV-6), and Epstein-Barr virus (EBV), have been repeatedly linked to multiple sclerosis (MS). Objective The aim of this study was to investigate HHV-6 and EBV reactive oligoclonal bands (OCBs), and viral DNA in the intrathecal compartment in MS. Methods The reactivity of OCBs in cerebrospinal fluid (CSF) for EBV and HHV-6 antigens and stability of virus reactive OCBs over time were studied in a well-characterized MS patient cohort. Associations between virus reactive OCBs and viral DNA in CSF (and any clinical and/or radiological findings) were investigated. Results Of patients with MS, 38% had OCBs reactive to either one of the viruses studied, compared to none in the patients with other inflammatory neurological diseases (p=0.005). The banding pattern of virus reactive OCBs remained the same over time. Furthermore, MS patients with viral DNA in CSF had more contrast enhancing lesions (CELs). Conclusion The stable presence of herpesvirus reactive OCBs in CSF further strengthens the association of MS with these viruses. The finding that herpesviruses might be linked to the appearance of active lesions warrants investigation of new therapeutic strategies to treat these viruses in MS. PMID:23722324

Reactive powder concrete reinforced with steel fibres exposed to high temperatures

NASA Astrophysics Data System (ADS)

Alrekabi, T. Kh; Cunha, V. M. C. F.; Barros, J. A. O.

2017-09-01

An experimental investigation was carried out to assess the mechanical properties of reactive powder concrete (RPC) reinforced with steel fibres (2% in vol.) when exposed to high temperatures. The compressive, flexural and tensile strength, modulus of elasticity and post-cracking behaviour were assessed after specimens’ exposure to different high temperatures ranging from 400 to 700°C. The mechanical properties of the RPC were assessed for specimens dried for 24 hours at 60 °C and 100 °C. Partially dried specimens (60 °C) exhibited explosive spalling at nearby 450 °C, while fully dried RPC specimens (100 °C) maintained their integrity after heating exposure. In general, the mechanical properties of RPC significantly decreased with the increase of the temperature exposure. The rate of decrease with temperature of the compressive, tensile and flexural strengths, as well the corresponding post-cracking residual stresses was higher for exposure temperatures above the 400 °C.

Assess and improve the sustainability of water treatment facility using Computational Fluid Dynamics

NASA Astrophysics Data System (ADS)

Zhang, Jie; Tejada-Martinez, Andres; Lei, Hongxia; Zhang, Qiong

2016-11-01

Fluids problems in water treatment industry are often simplified or omitted since the focus is usually on chemical process only. However hydraulics also plays an important role in determining effluent water quality. Recent studies have demonstrated that computational fluid dynamics (CFD) has the ability to simulate the physical and chemical processes in reactive flows in water treatment facilities, such as in chlorine and ozone disinfection tanks. This study presents the results from CFD simulations of reactive flow in an existing full-scale ozone disinfection tank and in potential designs. Through analysis of the simulation results, we found that baffling factor and CT10 are not optimal indicators of disinfection performance. We also found that the relationship between effluent CT (the product of disinfectant concentration and contact time) obtained from CT transport simulation and baffling factor depends on the location of ozone release. In addition, we analyzed the environmental and economic impacts of ozone disinfection tank designs and developed a composite indicator to quantify the sustainability of ozone disinfection tank in technological, environmental and economic dimensions.

Development of Highly Durable and Reactive Regenerable Magnesium-Based Sorbents for CO2 Separation in Coal Gasification Process

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

Javad Abbasian; Armin Hassanzadeh Khayyat; Rachid B. Slimane

The specific objective of this project was to develop physically durable and chemically regenerable MgO-based sorbents that can remove carbon dioxide from raw coal gas at operating condition prevailing in IGCC processes. A total of sixty two (62) different sorbents were prepared in this project. The sorbents were prepared either by various sol-gel techniques (22 formulations) or modification of dolomite (40 formulations). The sorbents were prepared in the form of pellets and in granular forms. The solgel based sorbents had very high physical strength, relatively high surface area, and very low average pore diameter. The magnesium content of the sorbentsmore » was estimated to be 4-6 % w/w. To improve the reactivity of the sorbents toward CO{sub 2}, The sorbents were impregnated with potassium salts. The potassium content of the sorbents was about 5%. The dolomite-based sorbents were prepared by calcination of dolomite at various temperature and calcination environment (CO{sub 2} partial pressure and moisture). Potassium carbonate was added to the half-calcined dolomite through wet impregnation method. The estimated potassium content of the impregnated sorbents was in the range of 1-6% w/w. In general, the modified dolomite sorbents have significantly higher magnesium content, larger pore diameter and lower surface area, resulting in significantly higher reactivity compared to the sol-gel sorbents. The reactivities of a number of sorbents toward CO{sub 2} were determined in a Thermogravimetric Analyzer (TGA) unit. The results indicated that at the low CO{sub 2} partial pressures (i.e., 1 atm), the reactivities of the sorbents toward CO{sub 2} are very low. At elevated pressures (i.e., CO{sub 2} partial pressure of 10 bar) the maximum conversion of MgO obtained with the sol-gel based sorbents was about 5%, which corresponds to a maximum CO{sub 2} absorption capacity of less than 1%. The overall capacity of modified dolomite sorbents were at least one order of

High accuracy differential pressure measurements using fluid-filled catheters - A feasibility study in compliant tubes.

PubMed

Rotman, Oren Moshe; Weiss, Dar; Zaretsky, Uri; Shitzer, Avraham; Einav, Shmuel

2015-09-18

High accuracy differential pressure measurements are required in various biomedical and medical applications, such as in fluid-dynamic test systems, or in the cath-lab. Differential pressure measurements using fluid-filled catheters are relatively inexpensive, yet may be subjected to common mode pressure errors (CMP), which can significantly reduce the measurement accuracy. Recently, a novel correction method for high accuracy differential pressure measurements was presented, and was shown to effectively remove CMP distortions from measurements acquired in rigid tubes. The purpose of the present study was to test the feasibility of this correction method inside compliant tubes, which effectively simulate arteries. Two tubes with varying compliance were tested under dynamic flow and pressure conditions to cover the physiological range of radial distensibility in coronary arteries. A third, compliant model, with a 70% stenosis severity was additionally tested. Differential pressure measurements were acquired over a 3 cm tube length using a fluid-filled double-lumen catheter, and were corrected using the proposed CMP correction method. Validation of the corrected differential pressure signals was performed by comparison to differential pressure recordings taken via a direct connection to the compliant tubes, and by comparison to predicted differential pressure readings of matching fluid-structure interaction (FSI) computational simulations. The results show excellent agreement between the experimentally acquired and computationally determined differential pressure signals. This validates the application of the CMP correction method in compliant tubes of the physiological range for up to intermediate size stenosis severity of 70%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of stress factors associated with KHV reactivation and pathological effects from KHV reactivation.

PubMed

Lin, Lisa; Chen, Sammi; Russell, Duncan S; Löhr, Christiane V; Milston-Clements, Ruth; Song, Tiffany; Miller-Morgan, Tim; Jin, Ling

2017-08-15