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Sample records for highly reactive fluids

  1. Ascitic Fluid High Sensitive C-Reactive Protein (hs-CRP). A Prognostic Marker in Cirrhosis with Spontaneous Bacterial Peritonitis

    PubMed Central

    Kadam, Nakul; Shukla, Samarth; Gupta, Kriti

    2016-01-01

    Introduction C-Reactive Protein (CRP) is an acute phase reactant. Its level increases in the presence of acute or chronic inflammation and infections. High sensitive CRP (hs-CRP) is more sensitive than CRP as an inflammatory marker. High sensitive CRP has been known to be elevated in chronic liver diseases and Spontaneous Bacterial Peritonitis (SBP). Aim The aim of the study was to establish the role of ascitic fluid high sensitive C-reactive protein (hs –CRP) as a prognostic indicator in patients with SBP. Materials and Methods A total of 100 patients with decompensated cirrhosis admitted in medicine ward and ICU were included, of which 50 patients of acute bacterial peritonitis were used as study group and 50 patients of sterile ascites were used as control group. Hs-CRP level of cases and controls were estimated. SBP cases were treated with its standard recommended antibiotic therapy and hs-CRP level was again estimated after 5 days of antibiotic therapy or at the time of discharge. Results The mean level of hs-CRP before antibiotic therapy of the patients with SBP was significantly higher than that of the patients without spontaneous bacterial peritonitis (t98=17.72; p=0.0001). The mean level of hs-CRP at 5th day or discharge after initiation of antibiotic therapy was significantly lower than that of level of hs-CRP before initiation of antibiotic therapy (p<0.05). The mean hs-CRP of the cases with poor outcome (death and prolonged hospital stay) was significantly higher than others. Conclusion Ascitic fluid hs-CRP level can be considered as a surrogate prognostic marker in cases of Cirrhosis with SBP. PMID:27190862

  2. Method for reactivating catalysts and a method for recycling supercritical fluids used to reactivate the catalysts

    DOEpatents

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2008-08-05

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  3. High-Density Peptide Microarray Analysis of IgG Autoantibody Reactivities in Serum and Cerebrospinal Fluid of Multiple Sclerosis Patients*

    PubMed Central

    Hecker, Michael; Fitzner, Brit; Wendt, Matthias; Lorenz, Peter; Flechtner, Kristin; Steinbeck, Felix; Schröder, Ina; Thiesen, Hans-Jürgen; Zettl, Uwe Klaus

    2016-01-01

    Intrathecal immunoglobulin G (IgG) synthesis and oligoclonal IgG bands in cerebrospinal fluid (CSF) are hallmarks of multiple sclerosis (MS), but the antigen specificities remain enigmatic. Our study is the first investigating the autoantibody repertoire in paired serum and CSF samples from patients with relapsing-remitting MS (RRMS), primary progressive MS (PPMS), and other neurological diseases by the use of high-density peptide microarrays. Protein sequences of 45 presumed MS autoantigens (e.g. MOG, MBP, and MAG) were represented on the microarrays by overlapping 15mer peptides. IgG reactivities were screened against a total of 3991 peptides, including also selected viral epitopes. The measured antibody reactivities were highly individual but correlated for matched serum and CSF samples. We found 54 peptides to be recognized significantly more often by serum or CSF antibodies from MS patients compared with controls (p values <0.05). The results for RRMS and PPMS clearly overlapped. However, PPMS patients presented a broader peptide-antibody signature. The highest signals were detected for a peptide mapping to a region of the Epstein-Barr virus protein EBNA1 (amino acids 392–411), which is homologous to the N-terminal part of human crystallin alpha-B. Our data confirmed several known MS-associated antigens and epitopes, and they delivered additional potential linear epitopes, which await further validation. The peripheral and intrathecal humoral immune response in MS is polyspecific and includes antibodies that are also found in serum of patients with other diseases. Further studies are required to assess the pathogenic relevance of autoreactive and anti-EBNA1 antibodies as well as their combinatorial value as biomarkers for MS. PMID:26831522

  4. 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.

  5. BIOMONITORING OF REACTIVE OXYGEN SPECIES IN BIOLOGICAL FLUIDS

    EPA Science Inventory

    Elevated levels of reactive oxygen species (ROS) are associated with several disease processes in humans, including cancer, asthma, diabetes, and cardiac disease. We have explored whether ROS can be measured directly in human fluids, and their value as a biomarker of exposure an...

  6. 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

  7. Point kinetics calculations with fully coupled thermal fluids reactivity feedback

    SciTech Connect

    Zhang, H.; Zou, L.; Andrs, D.; Zhao, H.; Martineau, R.

    2013-07-01

    The point kinetics model has been widely used in the analysis of the transient behavior of a nuclear reactor. In the traditional nuclear reactor system safety analysis codes such as RELAP5, the reactivity feedback effects are calculated in a loosely coupled fashion through operator splitting approach. This paper discusses the point kinetics calculations with the fully coupled thermal fluids and fuel temperature feedback implemented into the RELAP-7 code currently being developed with the MOOSE framework. (authors)

  8. Fluid-rock interaction: A reactive transport approach

    SciTech Connect

    Steefel, C.; Maher, K.

    2009-04-01

    Fluid-rock interaction (or water-rock interaction, as it was more commonly known) is a subject that has evolved considerably in its scope over the years. Initially its focus was primarily on interactions between subsurface fluids of various temperatures and mostly crystalline rocks, but the scope has broadened now to include fluid interaction with all forms of subsurface materials, whether they are unconsolidated or crystalline ('fluid-solid interaction' is perhaps less euphonious). Disciplines that previously carried their own distinct names, for example, basin diagenesis, early diagenesis, metamorphic petrology, reactive contaminant transport, chemical weathering, are now considered to fall under the broader rubric of fluid-rock interaction, although certainly some of the key research questions differ depending on the environment considered. Beyond the broadening of the environments considered in the study of fluid-rock interaction, the discipline has evolved in perhaps an even more important way. The study of water-rock interaction began by focusing on geochemical interactions in the absence of transport processes, although a few notable exceptions exist (Thompson 1959; Weare et al. 1976). Moreover, these analyses began by adopting a primarily thermodynamic approach, with the implicit or explicit assumption of equilibrium between the fluid and rock. As a result, these early models were fundamentally static rather than dynamic in nature. This all changed with the seminal papers by Helgeson and his co-workers (Helgeson 1968; Helgeson et al. 1969) wherein the concept of an irreversible reaction path was formally introduced into the geochemical literature. In addition to treating the reaction network as a dynamically evolving system, the Helgeson studies introduced an approach that allowed for the consideration of a multicomponent geochemical system, with multiple minerals and species appearing as both reactants and products, at least one of which could be

  9. Kerogen-Hydraulic Fracture Fluid Interactions: Reactivity and Contaminant Release

    NASA Astrophysics Data System (ADS)

    Dustin, M. K.; Jew, A. D.; Harrison, A. L.; Joe-Wong, C. M.; Thomas, D.; Maher, K.; Brown, G. E.; Bargar, J.

    2015-12-01

    The use of hydraulic fracturing of tight shales to produce oil and natural gas has grown significantly in recent years, yet it remains relatively inefficient, recovering only an estimated 5% and 25% of the oil and gas present, respectively. The need to improve efficiency and diminish environmental impact has prompted research into fundamental geochemical reactions occurring in shales. In particular, reactions between kerogen and fracture fluid components are poorly understood. Kerogen is the precursor of these hydrocarbons and contains metals in addition to organic material; it is also electron rich and therefore susceptible to oxidation and release of a variety of elements. Although some mineral phases in the shales are expected to undergo dissolution-precipitation reactions, kerogen is generally considered to be relatively unreactive [1]. Here we have investigated reactions between isolated kerogen and a hydraulic fracturing fluid typical of that used in the Marcellus shale. These experiments show that kerogen, as well as redox-sensitive minerals within shales, react with fracture fluid. In particular, kerogen exhibited more extensive release of certain metals (e.g. Al, Ba, Cu, among others) than was observed for bulk shale under the same experimental conditions. This evidence suggests that kerogen may be far more reactive to fracture fluids than previously thought. In particular, these results suggest that kerogen may significantly impact the compositions of produced waters, which have previously been attributed solely to mineral reactions. They also emphasize the need for further characterization of kerogen and its reactions with complex hydraulic fracturing fluids. [1] Vandenbroucke and Largeau (2007) Org. Geochem.

  10. 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.

  11. 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.

  12. ORIGIN OF THERMAL FLUIDS AT LASSEN VOLCANIC NATIONAL PARK: EVIDENCE FROM NOBLE AND REACTIVE GAS ABUNDANCES.

    USGS Publications Warehouse

    Truesdell, Alfred H.; Mazor, Emanuel; Nehring, Nancy L.

    1983-01-01

    Thermal fluid discharges at Lassen are dominated by high-altitude fumaroles and acid-sulfate hot springs in the Park, and lower altitude, neutral, high-chloride hot springs in Mill Valley 7-10 km to the south. The interrelations of these fluids have been studied by noble and reactive gas analyses. Atmospheric noble gas (ANG) contents of superheated fumaroles are similar to those of air-saturated recharge water (ASW) at 5 degree C and 2500-m elevation. Low-elevation, high-chloride, hot-spring waters are highly depleted in ANG, relative to the ASW. The surface temperatures and gas chemistry of the fumaroles and hot springs suggest that steam originating from partial to near-complete vaporization of liquid from a boiling, high-chloride, hot water aquifer is decompressed adiabatically, and more or less mixed with shallow groundwater to form superheated and drowned fumaroles within the Park. Refs.

  13. 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.

  14. Fluid escape from subduction zones controlled by channel-forming reactive porosity

    NASA Astrophysics Data System (ADS)

    Plümper, Oliver; John, Timm; Podladchikov, Yuri Y.; Vrijmoed, Johannes C.; Scambelluri, Marco

    2016-12-01

    Water within the oceanic lithosphere is returned to Earth's surface at subduction zones. Observations of metamorphosed veins preserved in exhumed slabs suggest that fluid can escape via channel networks. Yet, it is unclear how such channels form that allow chemically bound water to escape the subducting slab as the high pressures during subduction reduce the porosity of rocks to nearly zero. Here we use multiscale rock analysis combined with thermodynamic modelling to show that fluid flow initiation in dehydrating serpentinites is controlled by intrinsic chemical heterogeneities, localizing dehydration reactions at specific microsites. Porosity generation is directly linked to the dehydration reactions and resultant fluid pressure variations force the reactive fluid release to organize into vein networks across a wide range of spatial scales (μm to m). This fluid channelization results in large-scale fluid escape with sufficient fluxes to drain subducting plates. Moreover, our findings suggest that antigorite dehydration reactions do not cause instantaneous rock embrittlement, often presumed as the trigger of intermediate-depth subduction zone seismicity.

  15. Self-Organizing Reactive Fluid Escape from Dehydrating Rocks

    NASA Astrophysics Data System (ADS)

    John, T.; Pluemper, O.; Podladchikov, Y.; Vrijmoed, J. C.; Scambelluri, M.

    2014-12-01

    Water escape from dehydrating rocks within the Earth's interior is a key process for long-term global water and element cycles, eg. at subduction zones a fluid escape mechanism must exist that prevents ocean water to be drained into the mantle. Existing fluid flow models require a priori physical assumptions (eg. preexisting porosity) and cannot resolve the evolution from initial fluid production to flow channelization. In order to develop a model of this evolution, we need to unravel natural laboratories that display the incipient dehydration stages and the micro- to macro-scale fluid escape route evolution. The Erro-Tobbio meta-serpentinites (Italy) provide a unique snapshot into these early dehydration stages, recording the breakdown of hydrous antigorite to anhydrous olivine plus fluid and the formation of an olivine-vein network. We find that dehydration, fluid pooling, and flow initiation are controlled by micro-scale compositional rock differences. Our model starts with a rock in which all water is stored in solid and any preexisting porosity is negligible (zero-porosity case). As the rock descents into the mantle increasing T will initiate dehydration reactions, dividing the rock continuously into a dry solid and a fluid-filled porosity. Spatially variable reaction progress results in dynamically evolving porosity/permeability and heterogeneous fluid-pore pressure distributions. Fluid-pressure gradient relaxation causes fluid flow and its thermodynamic feedback triggers reactions to progress, resulting in a self-amplifying process. Our new thermodynamic-mechanical model for reaction-porosity waves shows that fluid flow occurs solely in the reaction products and self-organizes into channelized fluid escape networks. This holds the key to formulating future quantitative models that address spatiotemporal processes such as the coupling between fluid release at depth and volcanic eruptions and the amounts of structurally bound water transferred into deep Earth.

  16. Core-flood experiment for transport of reactive fluids in rocks.

    PubMed

    Ott, H; de Kloe, K; van Bakel, M; Vos, F; van Pelt, A; Legerstee, P; Bauer, A; Eide, K; van der Linden, A; Berg, S; Makurat, A

    2012-08-01

    Investigation of the transport of reactive fluids in porous rocks is an intriguing but challenging task and relevant in several areas of science and engineering such as geology, hydrogeology, and petroleum engineering. We designed and constructed an experimental setup to investigate physical and chemical processes caused by the flow of reactive and volatile fluids such as supercritical CO(2) and/or H(2)S in geological formations. Potential applications are geological sequestration of CO(2) in the frame of carbon capture and storage and acid-gas injection for sulfur disposal and/or enhanced oil recovery. The present paper outlines the design criteria and the realization of reactive transport experiments on the laboratory scale. We focus on the spatial and time evolution of rock and fluid composition as a result of chemical rock fluid interaction and the coupling of chemistry and fluid flow in porous rocks.

  17. 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)

  18. Chalk-microfluidic: flooding microsystems with reactive fluids

    NASA Astrophysics Data System (ADS)

    Neuville, Amélie; Dysthe, Dag Kristian; Li, Lei; Hiorth, Aksel

    2014-05-01

    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. Part of the reason for this is that there are very few in-situ observations of how the water chemistry affects fluid distributions on the pore scale, and/or the pore surface characteristics. In this work, as a first step, our aim is to focus on in-situ observations of single phase flow and interactions at the pore scale. In order to work at this small scale, we first investigate how to control the flow location. We propose to use the same principle as "paper-microfluidic": some areas of the chalk are chemically treated so that no fluid flows inside while other areas let the fluids flow in the chalk pores. Since chalk and paper obviously has different mechanical behavior, we need to adapt this technique. Custom-made microsystems with chalk and calcite will be presented. We will then show experiments with reacting fluids in these microsystems. These experiments are observed using wide field fluorescence microscopy and white light vertical/phase shift interferometric microscopy.

  19. Geothermal Fluid Interaction with Mafic Rocks in Porous Media - AN Experimental and Reactive Transport Modeling Study

    NASA Astrophysics Data System (ADS)

    Stefansson, A.

    2013-12-01

    Reaction and reactive transport modeling is becoming an increasingly popular method to study fluid-rock interaction and fluid transport on small to large scales. In this study, fluid-rock experiments were carried out and the observations compared with the results of reaction and reactive transport models. The systems studied included fluid-rock interaction of olivine on one hand and basaltic glass on the other hand with dilute aqueous solutions containing CO2 at acid to neutral pH and temperatures from ambient to 250 °C. The experiments were conducted using batch type experiments in closed reactors and 1-D plug experiments in flow-through reactors and the solution chemistry, the reaction progress, secondary mineralization and porosity changes analyzed as a function of time. The reaction and 1-D reactive transport simulations were conducted with the aid of the PHREEQC program. For the simulations the thermodynamic database for mineral reactions was largely updated and the kinetics of mineral dissolution as well as mineral nucleation and crystal growth was incorporated. According to the experimental results and the reactive transport simulations, olivine and basaltic glass progressively dissolves forming secondary minerals and solutes that are partially transported out of them column (system). The exact reaction path was found to depend on solution composition and pH and reaction progress (time). The mass movement of the system at a particular steady state as well as porosity changes may be divided into three stages. Stage I is characterized by initial olivine or basaltic glass leaching, stage II is characterized by progressive mineral formation and decrease in porosity and stage III is characterized by remobilization of the previously formed secondary minerals and eventual increase in porosity. The reaction and reactive transport modeling was found to simulate reasonable the reaction path as a function of reaction time. However, exact mass movement and time

  20. Numerical modelling of fault reactivation in carbonate rocks under fluid depletion conditions - 2D generic models with a small isolated fault

    NASA Astrophysics Data System (ADS)

    Zhang, Yanhua; Clennell, Michael B.; Delle Piane, Claudio; Ahmed, Shakil; Sarout, Joel

    2016-12-01

    This generic 2D elastic-plastic modelling investigated the reactivation of a small isolated and critically-stressed fault in carbonate rocks at a reservoir depth level for fluid depletion and normal-faulting stress conditions. The model properties and boundary conditions are based on field and laboratory experimental data from a carbonate reservoir. The results show that a pore pressure perturbation of -25 MPa by depletion can lead to the reactivation of the fault and parts of the surrounding damage zones, producing normal-faulting downthrows and strain localization. The mechanism triggering fault reactivation in a carbonate field is the increase of shear stresses with pore-pressure reduction, due to the decrease of the absolute horizontal stress, which leads to an expanded Mohr's circle and mechanical failure, consistent with the predictions of previous poroelastic models. Two scenarios for fault and damage-zone permeability development are explored: (1) large permeability enhancement of a sealing fault upon reactivation, and (2) fault and damage zone permeability development governed by effective mean stress. In the first scenario, the fault becomes highly permeable to across- and along-fault fluid transport, removing local pore pressure highs/lows arising from the presence of the initially sealing fault. In the second scenario, reactivation induces small permeability enhancement in the fault and parts of damage zones, followed by small post-reactivation permeability reduction. Such permeability changes do not appear to change the original flow capacity of the fault or modify the fluid flow velocity fields dramatically.

  1. 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

  2. Immune reactivity after high-dose irradiation

    SciTech Connect

    Gassmann, W.; Wottge, H.U.; von Kolzynski, M.; Mueller-Ruchholtz, W.

    1986-03-01

    Immune reactivity after total-body irradiation was investigated in rats using skin graft rejection as the indicator system. After sublethal irradiation with 10.5 Gy (approximately 50% lethality/6 weeks) the rejection of major histocompatibility complex allogeneic skin grafts was delayed significantly compared with nonirradiated control animals (28 versus 6.5 days). In contrast, skin grafts were rejected after 7.5 days in sublethally irradiated animals and 7 days in lethally irradiated animals if additional skin donor type alloantigens--namely, irradiated bone marrow cells--were given i.v. either simultaneously or with a delay of not more than 24 hr after the above conditioning regimen. These reactions were alloantigen-specific. They were observed in six different strain combinations with varying donors and recipients. Starting on day 2 after irradiation, i.v. injection of bone marrow gradually lost its effectivity and skin grafts were no longer rejected with uniform rapidity; skin donor marrow given on days 4 or 8 did not accelerate skin graft rejection at all. These data show that for approximately 1-2 days after high-dose total-body irradiation rats are still capable of starting a vigorous immune reaction against i.v.-injected alloantigens. The phenomenon of impaired rejection of skin grafted immediately after high-dose irradiation appears to result from the poor accessibility of skin graft alloantigens during the early postirradiation phase when vascularization of the grafted skin is insufficient.

  3. A Numerical Hydro-Chemo-Mechanical Model for Fault Activation under Reactive Fluid Flow

    NASA Astrophysics Data System (ADS)

    Pouya, A.; Tounsi, H.; Rohmer, J.

    2015-12-01

    The migration of CO2-rich fluid in fractured rock masses can cause processes such as mineral dissolution and precipitation, chemically induced weakening, which can affect the long-term mechanical and transport properties of the rock mass as well as the stability of fault systems. Some numerical approaches are already available in the literature for modelling the dissolution/precipitation phenomena in fractures (e.g. Yasuhara & Elsworth 2007) as well as subcritical crack propagation (e.g. Park et al. 2007). Generally, the dissolution is supposed to increase the rock porosity and, in this way, decrease the rock strength. Some experimental data are available for the variation of rock strength and stiffness parameters with the porosity and so as a consequence of dissolution process (Bemer et al. 2004). Also the effect of chemical processes on the mechanical stability has been studied and modelled numerically in the framework of continuum materials and the context, in particular, of weathering in underground galleries (Ghabezloo & Pouya 2006). In the context of fault systems, a complete numerical modelling of the stability evolution with the flow of a reactive fluid has not yet been done. In this paper we present a simplified, but complete, set of equations for a whole system of coupled hydro-chemo-mechanical process of reactive fluid flow inside a fault. These equations have been implemented in Porofis, a FEM numerical code specially conceived for HCM processes in porous fractured media. We show how this numerical method allows to model the coupled HCM processes in the fault and the evolution of the mechanical stability in presence of in situ stresses and reactive fluid flow.

  4. On the Inclusion of Inorganic Chemical Reactivity in High School Chemistry: The Reactivity Network.

    ERIC Educational Resources Information Center

    Mellon, E. K.

    1989-01-01

    Reports the function of the Reactivity Network which is to translate reactivity data from the primary literature into some 30 reviews for high school teachers and curriculum developers and to disseminate that information nationwide. Discusses a needs assessment done for the project. (MVL)

  5. High Performance Calcium Titanate Nanoparticle ER Fluids

    NASA Astrophysics Data System (ADS)

    Wang, Xuezhao; Shen, Rong; Wen, Weijia; Lu, Kunquan

    A type of calcium titanate (CTO) nanoparticles was synthesized by means of wet chemical method [1] without coating on the particles. The CTO/silicone oil ER fluid exhibits excellent electrorheological properties: high shear stress (~50-100 kPa) under dc electric field, a low current density (less than 2μA/cm2 at 5kV/mm), and long term stability against sedimentation. Although there are not special additives in the ER fluids, it is found from the chemical analysis that a trace of alkyl group, hydroxyl group, carbonyl group and some ions is remained in the particles which may dominate the ER response.

  6. Structures of High Density Molecular Fluids

    SciTech Connect

    Baer, B; Cynn, H; Iota, V; Yoo, C-S

    2002-02-01

    The goal of this proposal is to develop an in-situ probe for high density molecular fluids. We will, therefore, use Coherent Anti-Stokes Raman Spectroscopy (CARS) applied to laser heated samples in a diamond-anvil cell (DAC) to investigate molecular fluids at simultaneous conditions of high temperatures (T > 2000K) and high pressures (P > 10 GPa.) Temperatures sufficient to populate vibrational levels above the ground state will allow the vibrational potential to be mapped by CARS. A system capable of heating and probing these samples will be constructed. Furthermore, the techniques that enable a sample to be sufficiently heated and probed while held at static high pressure in a diamond-anvil-cell will be developed. This will be an in-situ investigation of simple molecules under conditions relevant to the study of detonation chemistry and the Jovain planet interiors using state of the art non-linear spectroscopy, diamond-anvil-cells, and laser heating technology.

  7. Electrophilic acid gas-reactive fluid, proppant, and process for enhanced fracturing and recovery of energy producing materials

    DOEpatents

    Fernandez, Carlos A.; Heldebrant, David J.; Bonneville, Alain H. R.; Jung, Hun Bok; Carroll, Kenneth

    2016-09-20

    An electrophilic acid gas-reactive fracturing and recovery fluid, proppant, and process are detailed. The fluid expands in volume to provide rapid and controlled increases in pressure that enhances fracturing in subterranean bedrock for recovery of energy-producing materials. Proppants stabilize openings in fractures and fissures following fracturing.

  8. Fluid hydrogen at high density - Pressure dissociation

    NASA Technical Reports Server (NTRS)

    Saumon, Didier; Chabrier, Gilles

    1991-01-01

    A model for the Helmholtz free energy of fluid hydrogen at high density and high temperature is developed. This model aims at describing both pressure and temperature dissociation and ionization and bears directly on equations of state of partially ionized plasmas, as encountered in astrophysical situations and high-pressure experiments. This paper focuses on a mixture of hydrogen atoms and molecules and is devoted to the study of the phenomenon of pressure dissociation at finite temperatures. In the present model, the strong interactions are described with realistic potentials and are computed with a modified Weeks-Chandler-Andersen fluid perturbation theory that reproduces Monte Carlo simulations to better than 3 percent. Theoretical Hugoniot curves derived from the model are in excellent agreement with experimental data.

  9. Taming the highly reactive oxonium ion.

    PubMed

    Haley, Michael M

    2009-01-01

    'Onium rings: Incorporation of the trivalent oxygen atom as a structural element within the tricyclic core of 1-3 imparts unprecedented stability to this "extraordinary" class of tertiary oxonium ions. Cation 1 is the least reactive and can be refluxed in water for 72 hours with no noticeable decomposition.

  10. 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.

  11. The mineral dissolution rate conundrum: Insights from reactive transport modeling of U isotopes and pore fluid chemistry in marine sediments

    NASA Astrophysics Data System (ADS)

    Maher, Kate; Steefel, Carl I.; DePaolo, Donald J.; Viani, Brian E.

    2006-01-01

    the laboratory-measured value, with the value depending primarily on the deviation from equilibrium. The reactive transport simulations demonstrate that the degree of undersaturation of the pore fluid with respect to plagioclase depends strongly on the rate of authigenic clay precipitation and the solubility of the clay minerals. The observed discrepancy is greatest for the linear TST model (10 5), less substantial with the Al-inhibition formulation (10 3), and decreases further if the clay minerals precipitate more slowly or as highly soluble precursor minerals (10 2). However, even several orders of magnitude variation in either the clay solubility or clay precipitation rates cannot completely account for the entire discrepancy while still matching pore water aluminum and silica data, indicating that the mineral dissolution rate conundrum must be attributed in large part to the gradual loss of reactive sites on silicate surfaces with time. The results imply that methods of mineral surface characterization that provide direct measurements of the bulk surface reactivity are necessary to accurately predict natural dissolution rates.

  12. 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

  13. A two-fluid model for reactive dilute solid-liquid mixtures with phase changes

    NASA Astrophysics Data System (ADS)

    Reis, Martina Costa; Wang, Yongqi

    2016-12-01

    Based on the Eulerian spatial averaging theory and the Müller-Liu entropy principle, a two-fluid model for reactive dilute solid-liquid mixtures is presented. Initially, some averaging theorems and properties of average quantities are discussed and, then, averaged balance equations including interfacial source terms are postulated. Moreover, constitutive equations are proposed for a reactive dilute solid-liquid mixture, where the formation of the solid phase is due to a precipitation chemical reaction that involves ions dissolved in the liquid phase. To this end, principles of constitutive theory are used to propose linearized constitutive equations that account for diffusion, heat conduction, viscous and drag effects, and interfacial deformations. A particularity of the model is that the mass interfacial source term is regarded as an independent constitutive variable. The obtained results show that the inclusion of the mass interfacial source term into the set of independent constitutive variables permits to easily describe the phase changes associated with precipitation chemical reactions.

  14. Direct numerical simulation of fluid-particle mass, momentum, and heat tranfers in reactive systems.

    NASA Astrophysics Data System (ADS)

    Hammouti, Abdelkader; Wachs, Anthony

    2015-11-01

    Many industrial processes like coal combustion, catalytic cracking, gas phase polymerization reactors and more recently biomass gasification and chemical looping involve two-phase reactive flows in which the continuous phase is a fluid and the dispersed phase consists of rigid particles. Improving both the design and the operating conditions of these processes represents a major scientific and industrial challenge in a context of markedly rising energy cost and sustainable development. Thus, it is above all important to better understand the coupling of hydrodynamic, chemical and thermal phenomena in those flows in order to be able to predict them reliably. The aim of our work is to build up a multi-scale modelling approach of reactive particulate flows and at first to focus on the development of a microscopic-scale including heat and mass transfers and chemical reactions for the prediction of particle-laden flows in dense and dilute regimes. A first step is the upgrading and the validation of our numerical tools via analytical solutions or empirical correlations when it is feasible. These couplings are implemented in a massively parallel numerical code that already enable to take a step towards the enhanced design of semi-industrial processes.

  15. A two-fluid model for reactive dilute solid-liquid mixtures with phase changes

    NASA Astrophysics Data System (ADS)

    Reis, Martina Costa; Wang, Yongqi

    2017-03-01

    Based on the Eulerian spatial averaging theory and the Müller-Liu entropy principle, a two-fluid model for reactive dilute solid-liquid mixtures is presented. Initially, some averaging theorems and properties of average quantities are discussed and, then, averaged balance equations including interfacial source terms are postulated. Moreover, constitutive equations are proposed for a reactive dilute solid-liquid mixture, where the formation of the solid phase is due to a precipitation chemical reaction that involves ions dissolved in the liquid phase. To this end, principles of constitutive theory are used to propose linearized constitutive equations that account for diffusion, heat conduction, viscous and drag effects, and interfacial deformations. A particularity of the model is that the mass interfacial source term is regarded as an independent constitutive variable. The obtained results show that the inclusion of the mass interfacial source term into the set of independent constitutive variables permits to easily describe the phase changes associated with precipitation chemical reactions.

  16. Reactive Plasticizers for High Temperature Quinoxaline Thermoplastics

    DTIC Science & Technology

    1976-06-01

    involves essentially two steps, consolidation of boardy prepreg into sheet stock and thermoforming the sheet stock into structural components. A...problem associated with the fabrication process is the high temperatures required in both the consolidation and thermoforming operations. High processing

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Reactive high power impulse magnetron sputtering: combining simulation and experiment

    NASA Astrophysics Data System (ADS)

    Kozak, Tomas; Vlcek, Jaroslav

    2016-09-01

    Reactive high-power impulse magnetron sputtering (HiPIMS) has recently been used for preparation of various oxide films with high application potential, such as TiO2, ZrO2, Ta2O5, HfO2, VO2. Using our patented method of pulsed reactive gas flow control with an optimized reactive gas inlet, we achieved significantly higher deposition rates compared to typical continuous dc magnetron depositions. We have developed a time-dependent model of the reactive HiPIMS. The model includes a depth-resolved description of the sputtered target (featuring sputtering, implantation and knock-on implantation processes) and a parametric description of the discharge plasma (dissociation of reactive gas, ionization and return of sputtered atoms and gas rarefaction). The model uses a combination of experimental and simulation data as input. We have calculated the composition of the target and substrate for several deposition conditions. The simulations predict a reduced compound coverage of the target in HiPIMS compared to the continuous dc sputtering regime which explains the increased deposition rate. The simulations show that an increased dissociation of oxygen in a HiPIMS discharge is beneficial to achieve stoichiometric films on the substrate at high deposition rates.

  2. Quantitative analysis of human cerebrospinal fluid proteins using a combination of cysteine tagging and amine-reactive isobaric labeling.

    PubMed

    Giron, Priscille; Dayon, Loïc; Turck, Natacha; Hoogland, Christine; Sanchez, Jean-Charles

    2011-01-07

    Highly complex and dynamic protein mixtures are hardly comprehensively resolved by direct shotgun proteomic analysis. As many proteins of biological interest are of low abundance, numerous analytical methodologies have been developed to reduce sample complexity and go deeper into proteomes. The present work describes an analytical strategy to perform cysteinyl-peptide subset enrichment and relative quantification through successive cysteine and amine-isobaric tagging. A cysteine-reactive covalent capture tag (C³T) allowed derivatization of cysteines and specific isolation on a covalent capture (CC) resin. The 6-plex amine-reactive tandem mass tags (TMT) served for relative quantification of the targeted peptides. The strategy was first evaluated on a model protein mixture with increasing concentrations to assess the specificity of the enrichment and the quantitative performances of the workflow. It was then applied to human cerebrospinal fluid (CSF) from post-mortem and ante-mortem samples. These studies confirmed the specificity of the C³T and the CC technique to cysteine-containing peptides. The model protein mixture analysis showed high precision and accuracy of the quantification with coefficients of variation and mean absolute errors of less than 10% on average. The CSF experiments demonstrated the potential of the strategy to study complex biological samples and identify differential brain-related proteins. In addition, the quantification data were highly correlated with a classical TMT experiment (i.e., without C³T cysteine-tagging and enrichment steps). Altogether, these results legitimate the use of this quantitative C³T strategy to enrich and relatively quantify cysteine-containing peptides in complex mixtures.

  3. Effect of Reactive Flow on Multi-size Scaling of Fluid Flow and Seismic Fracture Stiffness

    NASA Astrophysics Data System (ADS)

    Pyrak-Nolte, L. J.

    2014-12-01

    A goal of geophysical monitoring is to detect and characterize alterations in the subsurface induced by natural and anthropogenic processes that affect local fracture geometry and local fluid flow. Recently, we demonstrated that a key seismic signature of a fracture (specific stiffness) is related to its hydraulic properties if the aperture distributions have only weak spatial correlations. An open challenge remains to determine if this relationship holds for correlated aperture distributions and whether this relationship differs for fractures altered only by stress or also for those altered by reactive flow and stress. A finite-size scaling analysis was performed on fractures to determine the effect of correlated aperture distributions with and without chemical alteration on the fundamental scaling relationship between fracture stiffness and fracture flow behavior. Computational models were used to analyze fluid flow through a fracture undergoing deformation and chemical alteration. The numerical methods included a stratified percolation approach to generate pore-scale fracture void geometry, a combined conjugate-gradient method and fast-multipole method for determining fracture deformation, and a network model for simulating fluid flow through a fracture. Fracture apertures were chemically eroded based on the local flux field through the fracture. For correlated aperture distributions without chemical alteration, fracture stiffness captures the deformation of the fracture void geometry that includes both changes in contact area and aperture. This enabled a collapse of the numerical flow-stiffness data, from multiple length scales, to a single scaling function. When fracture apertures were slightly eroded, the flow-stiffness relationship exhibited the same functional form as the unaltered case, but the scaling of flow depended on the aperture of the critical neck. These results suggest that geophysical methods that characterize fracture stiffness have the

  4. Impact of fluid injection on fracture reactivation at The Geysers geothermal field

    NASA Astrophysics Data System (ADS)

    Martínez-Garzón, Patricia; Kwiatek, Grzegorz; Bohnhoff, Marco; Dresen, Georg

    2016-10-01

    We analyze the spatiotemporal distribution of fault geometries from seismicity induced by fluid injection at The Geysers geothermal field. The consistency of these faults with the local stress field is investigated using (1) the fault instability coefficient I comparing the orientation of a fault with the optimal orientation for failure in the assumed stress field and (2) the misfit angle β between slip vectors observed from focal mechanisms and predicted from stress tensor. A statistical approach is applied to calculate the most likely fault instabilities considering the uncertainties from focal mechanisms and stress inversion. We find that faults activated by fluid injection may display a broad range in orientations. About 72% of the analyzed seismicity occurs on faults with favorable orientation for failure with respect to the stress field. However, a number of events are observed either to occur on severely misoriented faults or to slip in a different orientation than predicted from stress field. These events mostly occur during periods of high injection rates and are located in proximity to the injection wells. From the stress inversion, the friction coefficient providing the largest overall instability is μ = 0.5. About 91% of the events are activated with an estimated excess pore pressure <10 MPa, in agreement with previous models considering the combined effect of thermal and poroelastic stress changes from fluid injection. Furthermore, high seismic activity and largest magnitudes occur on favorably oriented faults with large instability coefficients and low slip misfit angles.

  5. Reactive oxygen species and anti-oxidant defences in swine follicular fluids.

    PubMed

    Basini, Giuseppina; Simona, Bussolati; Santini, Sujen Eleonora; Grasselli, Francesca

    2008-01-01

    A growing body of evidence indicates that the pro-oxidant/anti-oxidant balance inside the ovarian follicle plays an important role in folliculogenesis. Therefore, the aim of the present study was to assess the redox status of follicular fluids collected from different-sized swine follicles. We quantified the most important reactive oxygen species (ROS), namely superoxide anion (O(2)(-)), hydrogen peroxide and hydroperoxides (ROOH); in addition, we examined the activity of the detoxifying enzymes superoxide dismutase, catalase (CAT) and glutathione peroxidase and the total non-enzymatic antioxidant capacity as determined by the ferric-reducing anti-oxidant power assay. Our data demonstrate that oxidative stress does not affect follicle growth because O(2)(-) levels do not change during follicle development, whereas concentrations of H2O2 and ROOH are reduced (P < 0.05). Surprisingly, all non-enzymatic and enzymatic scavengers examined in the present study, except for CAT, demonstrated reduced activity during follicle development (P < 0.05). Taken together, these results suggest that other factors could be involved in ROS detoxification during follicle development.

  6. 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.

  7. Chemical evolution of a high-temperature fracturing fluid

    SciTech Connect

    La Grone, C.C.; Baumgartner, S.A.; Woodroof, R.A.

    1985-10-01

    The use of conventional fracturing fluids has been limited traditionally to wells with BHT's of 250/sup 0/F (121/sup 0/C) or less. Above 250/sup 0/F (121/sup 0/C), high polymer concentrations and/or large fluid volumes are required to maintain effective fluid viscosities in the fracture. However, high polymer concentrations lead to high friction pressures, high costs, and high gel residue levels. The large fluid volumes also increase significantly the cost of the treatment. Greater understanding of fracturing fluid properties has led to the development of a crosslinked fracturing fluid designed specifically for wells with BHT's above 250/sup 0/F (121/sup 0/C). The specialized chemistry of this fluid combines a high-pH hydroxypropyl guar gum (HPG) solution with a high-temperature gel stabilizer and a proprietary crosslinker. The fluid remains stable at 250 to 350/sup 0/F (121 to 177/sup 0/C) for extended periods of time under shear. This paper describes the rheological evaluations used in the systematic development of this fracturing fluid. In field applications, this fracturing fluid has been used to stimulate successfully wells with BHT's ranging from 250 to 540/sup 0/F (121 to 282/sup 0/C). Case histories that include pretreatment and posttreatment production data are presented.

  8. Estimation of the reactive mineral surface area during CO2-rich fluid-rock interaction: the influence of neogenic phases

    NASA Astrophysics Data System (ADS)

    Scislewski, A.; Zuddas, P.

    2010-12-01

    Mineral dissolution and precipitation reactions actively participate to control fluid chemistry during water-rock interaction. It is however, difficult to estimate and well normalize bulk reaction rates if the mineral surface area exposed to the aqueous solution and effectively participating on the reactions is unknown. We evaluated the changing of the reactive mineral surface area during the interaction between CO2-rich fluids and Albitite/Granitoid rocks (similar mineralogy but different abundances), reacting under flow-through conditions. Our methodology, adopting an inverse modeling approach, is based on the estimation of dissolution rate and reactive surface area of the different minerals participating in the reactions by the reconstruction the chemical evolution of the interacting fluids. The irreversible mass-transfer processes is defined by a fractional degree of advancement, while calculations were carried out for Albite, Microcline, Biotite and Calcite assuming that the ion activity of dissolved silica and aluminium ions was limited by the equilibrium with quartz and kaolinite. Irrespective of the mineral abundance in granite and albitite, we found that mineral dissolution rates did not change significantly in the investigated range of time where output solution’s pH remained in the range between 6 and 8, indicating that the observed variation in fluid composition depends not on pH but rather on the variation of the parent mineral’s reactive surface area. We found that the reactive surface area of Albite varied by more than 2 orders of magnitude, while Microcline, Calcite and Biotite surface areas changed by 1-2 orders of magnitude. We propose that parent mineral chemical heterogeneity and, particularly, the stability of secondary mineral phases may explain the observed variation of the reactive surface area of the minerals. Formation of coatings at the dissolving parent mineral surfaces significantly reduced the amount of surface available to react

  9. Fluid flow and reactive transport around potential nuclear waste emplacement tunnels at Yucca Mountain, Nevada.

    PubMed

    Spycher, N F; Sonnenthal, E L; Apps, J A

    2003-01-01

    The evolution of fluid chemistry and mineral alteration around a potential waste emplacement tunnel (drift) is evaluated using numerical modeling. The model considers the flow of water, gas, and heat, plus reactions between minerals, CO(2) gas, and aqueous species, and porosity-permeability-capillary pressure coupling for a dual permeability (fractures and matrix) medium. Two possible operating temperature modes are investigated: a "high-temperature" case with temperatures exceeding the boiling point of water for several hundred years, and a "low-temperature" case with temperatures remaining below boiling for the entire life of the repository. In both cases, possible seepage waters are characterized by dilute to moderate salinities and mildly alkaline pH values. These trends in fluid composition and mineral alteration are controlled by various coupled mechanisms. For example, upon heating and boiling, CO(2) exsolution from pore waters raises pH and causes calcite precipitation. In condensation zones, this CO(2) redissolves, resulting in a decrease in pH that causes calcite dissolution and enhances feldspar alteration to clays. Heat also enhances dissolution of wall rock minerals leading to elevated silica concentrations. Amorphous silica precipitates through evaporative concentration caused by boiling in the high-temperature case, but does not precipitate in the low-temperature case. Some alteration of feldspars to clays and zeolites is predicted in the high-temperature case. In both cases, calcite precipitates when percolating waters are heated near the drift. The predicted porosity decrease around drifts in the high-temperature case (several percent of the fracture volume) is larger by at least one order of magnitude than in the low temperature case. Although there are important differences between the two investigated temperature modes in the predicted evolution of fluid compositions and mineral alteration around drifts, these differences are largely within to

  10. Fluid flow and reactive transport around potential nuclear waste emplacement tunnels at Yucca Mountain, Nevada

    SciTech Connect

    Spycher, N.F.; Sonnenthal, E.L.; Apps, J.A.

    2002-09-01

    The evolution of fluid chemistry and mineral alteration around a potential waste emplacement tunnel (drift) is evaluated using numerical modeling. The model considers the flow of water, gas, and heat, plus reactions between minerals, CO{sub 2} gas, and aqueous species, and porosity permeability-capillary pressure coupling for a dual permeability (fractures and matrix) medium. Two possible operating temperature modes are investigated: a ''high-temperature'' case with temperatures exceeding the boiling point of water for several hundred years, and a ''low-temperature'' case with temperatures remaining below boiling for the entire life of the repository. In both cases, possible seepage waters are characterized by dilute to moderate salinities and mildly alkaline pH values. These trends in fluid composition and mineral alteration are controlled by various coupled mechanisms. For example, upon heating and boiling, CO{sub 2} exsolution from pore waters raises pH and causes calcite precipitation. In condensation zones, this CO{sub 2} redissolves, resulting in a decrease in pH that causes calcite dissolution and enhances feldspar alteration to clays. Heat also enhances dissolution of wallrock minerals leading to elevated silica concentrations. Amorphous silica precipitates through evaporative concentration caused by boiling in the high-temperature case, but does not precipitate in the low-temperature case. Some alteration of feldspars to clays and zeolites is predicted in the high-temperature case. In both cases, calcite precipitates when percolating waters are heated near the drift. The predicted porosity decrease around drifts in the high-temperature case (several percent of the fracture volume) is larger by at least one order of magnitude than in the low temperature case. Although there are important differences between the two investigated temperature modes in the predicted evolution of fluid compositions and mineral alteration around drifts, these differences are

  11. The Hazards of Reactive Chemicals in High School Laboratories.

    ERIC Educational Resources Information Center

    Forlin, Peter

    Chemical reactivity is a major area of risk in high school laboratories. This paper reports on a study that has provided a research-based framework for risk management in Australian chemical education. The chemical practice model of risk management is considered with respect to kinetic factors; catalysts; concentrations and proportions;…

  12. Pore-Scale Geochemical Reactivity Associated with CO2 Storage: New Frontiers at the Fluid-Solid Interface.

    PubMed

    Noiriel, Catherine; Daval, Damien

    2017-03-31

    The reactivity of carbonate and silicate minerals is at the heart of porosity and pore geometry changes in rocks injected with CO2, which ultimately control the evolution of flow and transport properties of fluids in porous and/or fractured geological reservoirs. Modeling the dynamics of CO2-water-rock interactions is challenging because of the resulting large geochemical disequilibrium, the reservoir heterogeneities, and the large space and time scales involved in the processes. In particular, there is a lack of information about how the macroscopic properties of a reservoir, e.g., the permeability, will evolve as a result of geochemical reactions at the molecular scale. Addressing this point requires a fundamental understanding of how the microstructures influence the macroscopic properties of rocks. The pore scale, which ranges from a few nanometers to centimeters, has stood out as an essential scale of observation of geochemical processes in rocks. Transport or surface reactivity limitations due to the pore space architecture, for instance, are best described at the pore scale itself. It can be also considered as a mesoscale for aggregating and increasing the gain of fundamental understanding of microscopic interfacial processes. Here we focus on the potential application of a combination of physicochemical measurements coupled with nanoscale and microscale imaging techniques during laboratory experiments to improve our understanding of the physicochemical mechanisms that occur at the fluid-solid interface and the dynamics of the coupling between the geochemical reactions and flow and transport modifications at the pore scale. Imaging techniques such as atomic force microscopy, vertical scanning interferometry, focused ion beam transmission electron microscopy, and X-ray microtomography, are ideal for investigating the reactivity dynamics of these complex materials. Minerals and mineral assemblages, i.e., rocks, exhibit heterogeneous and anisotropic reactivity

  13. 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.

  14. Pyrite-driven reactive oxygen species formation in simulated lung fluid: implications for coal workers' pneumoconiosis.

    PubMed

    Harrington, Andrea D; Hylton, Shavonne; Schoonen, Martin A A

    2012-08-01

    The origin of coal worker's pneumoconiosis (CWP) has been long debated. A recent epidemiological study shows a correlation between what is essentially the concentration of pyrite within coal and the prevalence of CWP in miners. Hydrogen peroxide and hydroxyl radical, both reactive oxygen species (ROS), form as byproducts of pyrite oxidative dissolution in air-saturated water. Motivated by the possible importance of ROS in the pathogenesis of CWP, we conducted an experimental study to evaluate if ROS form as byproducts in the oxidative dissolution of pyrite in simulated lung fluid (SLF) under biologically applicable conditions and to determine the persistence of pyrite in SLF. While the rate of pyrite oxidative dissolution in SLF is suppressed by 51% when compared to that in air-saturated water, the initial amount of hydrogen peroxide formed as a byproduct in SLF is nearly doubled. Hydroxyl radical is also formed in the experiments with SLF, but at lower concentrations than in the experiments with water. The formation of these ROS indicates that the reaction mechanism for pyrite oxidative dissolution in SLF is no different from that in water. The elevated hydrogen peroxide concentration in SLF suggests that the decomposition, via the Fenton mechanism to hydroxyl radical or with Fe(III) to form water and molecular oxygen, is initially inhibited by the presence of SLF components. On the basis of the oxidative dissolution rate of pyrite measured in this paper, it is calculated that a respirable two micron pyrite particle will take over 3 years to dissolve completely.

  15. Reactive Oxygen Species Generation by Lunar Simulants in Simulated Lung Fluid

    NASA Astrophysics Data System (ADS)

    Schoonen, M. A.; Kaur, J.; Rickman, D.

    2015-12-01

    The current interest in human exploration of the Moon and other airless planetary bodies has rekindled research into the harmful effects of Lunar dust on human health. Our team has evaluated the spontaneous formation of Reactive Oxygen Species (ROS; hydroxyl radicals, superoxide, and hydrogen peroxide) of a suite of lunar simulants when dispersed in deionized water. Of these species, hydroxyl radical reacts almost immediately with any biomolecule leading to oxidative damage. Sustained production of OH radical as a result of mineral exposure can initiate or enhance disease. The results in deionized water indicate that mechanical stress and the absence of molecular oxygen and water, important environmental characteristics of the lunar environment, can lead to enhanced production of ROS in general. On the basis of the results with deionized water, a few of the simulants were selected for additional studies to evaluate the formation of hydrogen peroxide, a precursor of hydroxyl radical in Simulated Lung Fluid. These simulants dispersed in deionized water typically produce a maximum in H2O2 within 10 to 40 minutes. However, experiments in SLF show a slow steady increase in H2O2 concentration that has been documented to continue for as long as 7 hours. Control experiments with one simulant demonstrate that the rise in H2O2 depends on the availability of dissolved O2. We speculate that this continuous rise in oxygenated SLF might be a result of metal ion-mediated oxidation of organic components, such as glycine in SLF. Ion-mediated oxidation essentially allows dissolved molecular oxygen to react with dissolved organic compounds by forming a metal-organic complex. Results of separate experiments with dissolved Fe, Ni, and Cu and speciation calculations support this notion.

  16. Schlieren High Speed Imaging on Fluid Flow in Liquid Induced by Plasma-driven Interfacial Forces

    NASA Astrophysics Data System (ADS)

    Lai, Janis; Foster, John

    2016-10-01

    Effective plasma-based water purification depends heavily on the transport of plasma-derived reactive species from the plasma into the liquid. Plasma interactions at the liquid-gas boundary are known to drive circulation in the bulk liquid. This forced circulation is not well understood. A 2-D plasma- in-liquid water apparatus is currently being investigated as a means to study the plasma-liquid interface to understand not only reactive species flows but to also understand plasma- driven fluid dynamic effects in the bulk fluid. Using Schlieren high speed imaging, plasma-induced density gradients near the interfacial region and into the bulk solution are measured to investigate the nature of these interfacial forces. Plasma-induced flow was also measured using particle imaging velocimetry. NSF CBET 1336375 and DOE DE-SC0001939.

  17. Fluid Dynamics of High Performance Turbomachines.

    DTIC Science & Technology

    1987-12-01

    reflecting bound- ary conditions can be constructed. For the potential equation this was first done by Verdon et al [7] in 1975, and it is now the...for Time-Dependent Hyperbolic Systems. Center for Large Scale Scientific Computation CLaSSiC-87-16, Stanford University, Feb 1987. [7] J. M. Verdon ...Computational Fluid Dynamics Lab- oratory, 1986. [12] G. B. Whitham. Linear and Nonlinear Waves. John Wiley & Sons, 1974. [13] J. Mathews and R. L. Walker

  18. A fully-implicit finite-volume method for multi-fluid reactive and collisional magnetized plasmas on unstructured meshes

    NASA Astrophysics Data System (ADS)

    Alvarez Laguna, A.; Lani, A.; Deconinck, H.; Mansour, N. N.; Poedts, S.

    2016-08-01

    We present a Finite Volume scheme for solving Maxwell's equations coupled to magnetized multi-fluid plasma equations for reactive and collisional partially ionized flows on unstructured meshes. The inclusion of the displacement current allows for studying electromagnetic wave propagation in a plasma as well as charge separation effects beyond the standard magnetohydrodynamics (MHD) description, however, it leads to a very stiff system with characteristic velocities ranging from the speed of sound of the fluids up to the speed of light. In order to control the fulfillment of the elliptical constraints of the Maxwell's equations, we use the hyperbolic divergence cleaning method. In this paper, we extend the latter method applying the CIR scheme with scaled numerical diffusion in order to balance those terms with the Maxwell flux vectors. For the fluids, we generalize the AUSM+-up to multiple fluids of different species within the plasma. The fully implicit second-order method is first verified on the Hartmann flow (including comparison with its analytical solution), two ideal MHD cases with strong shocks, namely, Orszag-Tang and the MHD rotor, then validated on a much more challenging case, representing a two-fluid magnetic reconnection under solar chromospheric conditions. For the latter case, a comparison with pioneering results available in literature is provided.

  19. Electrocatalytic Reactivity for Oxygen Reduction of Palladium-Modified Carbon Nanotubes Synthesized in Supercritical Fluid

    SciTech Connect

    Lin, Yuehe; Cui, Xiaoli; Ye, Xiangrong

    2005-02-02

    The electrocatalytic reactivity of palladium-modified carbon nanotubes (Pd-CNTs) for the oxygen reduction reaction (ORR) was investigated at the glassy carbon electrode surface in 1 M H2SO4 saturated by oxygen. Carbon nanotubes modified by palladium nanoparticles were synthesized in supercritical carbon dioxide and characterized by transmission electron micrograph. The electrocatalytic activity of the CNTs film and Pd–CNTs film toward oxygen reduction was studied using cyclic voltammetry and linear sweep voltammetry methods. The molecular oxygen reduction at the Pd-CNTs electrode started at a more positive potential than that at the CNTs electrode. A possible reaction mechanism was proposed in which the ORR may proceed through two-step two-electron processes for the Pd-CNTs modified electrode. Experimental results revealed that Pd-CNTs possess a remarkable activity and high stability for oxygen reduction in acid medium, which implies the potential applications of the Pd–CNTs for constructing electrodes of fuel cells.

  20. Flow lasers. [fluid mechanics of high power continuous output operations

    NASA Technical Reports Server (NTRS)

    Christiansen, W. H.; Russell, D. A.; Hertzberg, A.

    1975-01-01

    The present work reviews the fluid-mechanical aspects of high-power continuous-wave (CW) lasers. The flow characteristics of these devices appear as classical fluid-mechanical phenomena recast in a complicated interactive environment. The fundamentals of high-power lasers are reviewed, followed by a discussion of the N2-CO2 gas dynamic laser. Next, the HF/DF supersonic diffusion laser is described, and finally the CO electrical-discharge laser is discussed.

  1. Plasmas in High-Density Medium - Supercritical fluid plasma and Cryogenic plasma

    NASA Astrophysics Data System (ADS)

    Terashima, Kazuo

    2011-10-01

    Recently, there has been a lot of attention to plasmas in high-density medium as novel plasmas from the views points of not only pure sciences but also various technologies. In this talk, two topics, supercritical fluid plasma and cryogenic plasma, will be discussed. First, plasmas generated in supercritical fluids (supercritical fluid plasma) provide a new reaction field that combines the high reactivity of plasmas with the unique characteristics of supercritical fluids, i.e. molecular clustering and density fluctuations near the critical point. An overview of the earliest studies on plasmas generated in supercritical fluids to recent advances in the field, including synthesis of novel nanomaterials such as highly-order diamondoid (diamond molecules), will be given. Second, continuing to thermal plasma (gas temperature Tg higher than a few thousands to millions of K) and low temperature plasma (Tg ranging from a few hundreds to thousands of K), plasma in a third range of gas temperatures (Tg lower than 300 K) is called cryogenic plasma (or cryoplasma) to distinguish it from thermal and low-temperature plasmas. In our group, the gas temperature of the plasma can be continuously controlled below room temperature (RT) down to a cryogenic temperature such as the boiling point of helium (4 K). In addition to the diagnostics, the application of cryogenic plasma to nanoporous material processing (low damage ashing of low-k materials) will be discussed. This work was supported financially in part by Grants-in-Aid.

  2. Time resolved ion energy distribution functions of non-reactive and reactive high power impulse magnetron sputtering of titanium

    NASA Astrophysics Data System (ADS)

    Grosse, Katharina; Breilmann, Wolfgang; Maszl, Christian; Benedikt, Jan; von Keudell, Achim

    2016-09-01

    High power impulse magnetron sputtering (HiPIMS) is a technique for thin film deposition and can be operated in reactive and non-reactive mode. The growth rate of HiPIMS in non-reactive mode reduces to 30% compared to direct current magnetron sputtering (dcMS) at same average power. However, the quality of the coatings produced with HiPIMS is excellent which makes these plasmas highly appealing. In reactive mode target poisoning is occurring which changes the plasma dynamics. An advantage of reactive HiPIMS is that it can be operated hysteresis-free which can result in a higher growth rate compared to dcMS. In this work thin films are deposited by a HiPIMS plasma which is generated by short pulses of 100 μs with high power densities in the range of 1 kW/cm2. Ar and Ar/N2 admixtures are used as a working gas to sputter a 2'' titanium target. The particle transport is analysed with time resolved ion energy distribution functions which are measured by a mass spectrometer with a temporal resolution of 2 μs. Phase resolved optical emission spectroscopy is executed to investigate the particle dynamics of different species. The time and energy resolved particle fluxes in non-reactive and reactive mode are compared and implications on the sputter process are discussed.

  3. Long term stability of magnetorheological fluids using high viscosity linear polysiloxane carrier fluids

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    Stability of magnetorheological fluids (MRFs) or suspensions has been a key issue in the development of various practical applications. In our prior work, it was experimentally confirmed that a high viscosity linear polysiloxane carrier fluid based MRF (hereinafter HVLP MRF) with 26% particle volume fraction (hereinafter 26 vol%) showed high sedimentation stability for 96 days because HVLP carrier fluids have remarkable shear thinning behavior, that is, very high viscosity at low shear rate but low viscosity at high shear rate. In addition, the effects of HVLP carrier fluid viscosity and carbonyl iron (CI) particle concentration on suspension stability were investigated with the objective of synthesizing highly stable HVLP MRFs for practical applications. The HVLP MRFs were synthesized by suspending nominally 32 vol% of CI particles in carrier fluids with different viscosities (i.e., 140, 440, and 800 Pa s). To illustrate the effect of particle concentration on suspension stability, because it is well known that suspension stability increases as particle concentration increases, two low concentrations, 5 and 10 vol%, and two high concentrations, 20 and 32 vol%, were prepared to demonstrate MRFs with relatively severe sedimentation, and stable suspensions, respectively. A vertical axis inductance monitoring system was employed to evaluate the suspension stability of the HVLP MRFs for 365 days by scanning the inductance of the MRF samples in a vertical fluid column, and logging this data with respect to height and time. In addition, the suspension stability of a commercially available MRF (i.e., Lord MRF-132DG) was also measured and compared with similar measurements for HVLP MRFs.

  4. Insights into Physics of Fluid Turbulence Using High Resolution Simulation

    NASA Astrophysics Data System (ADS)

    Chen, S.-Y.

    2001-06-01

    Turbulence is of universal importance in fluid flows. Its correct description thereby impacts such diverse fields as atmospheric pollutant dispersion, weather, commercial chemical processes, aircraft design, ship design, and ocean dynamics. The challenge of understanding turbulence, ``the last unsolved problem in classical statistical mechanics'' (according to Feynman), has been with us over 100 years. The difficulties in the physical understanding and modeling of fluid turbulence arise from the fundamental dynamical properties: strong nonlinearity; the simultaneous presence and interaction of a huge number of degrees of freedom, comprising a wide range of spatial scales; marked departure from statistical equilibrium. With emerging multi-teraflop computers, direct numerical simulation of fluid turbulence at high Reynolds numbers is becoming possible. In this talk, I will give an overview about the latest development of understanding fundamental physics of fluid turbulence, including two-D and three-D Navier-Stokes turbulence and passive scalar advection diffusion system, using high resolution numerical simulation.

  5. Self-propagating exothermic reaction analysis in Ti/Al reactive films using experiments and computational fluid dynamics simulation

    NASA Astrophysics Data System (ADS)

    Sen, Seema; Lake, Markus; Kroppen, Norman; Farber, Peter; Wilden, Johannes; Schaaf, Peter

    2017-02-01

    This study describes the self-propagating exothermic reaction in Ti/Al reactive multilayer foils by using experiments and computational fluid dynamics simulation. The Ti/Al foils with different molar ratios of 1Ti/1Al, 1Ti/2Al and 1Ti/3Al were fabricated by magnetron sputtering method. Microstructural characteristics of the unreacted and reacted foils were analyzed by using electronic and atomic force microscopes. After an electrical ignition, the influence of ignition potentials on reaction propagation has been experimentally investigated. The reaction front propagates with a velocity of minimum 0.68 ± 0.4 m/s and maximum 2.57 ± 0.6 m/s depending on the input ignition potentials and the chemical compositions. Here, the 1Ti/3Al reactive foil exhibits both steady state and unsteady wavelike reaction propagation. Moreover, the numerical computational fluid dynamics (CFD) simulation shows the time dependent temperature flow and atomic mixing in a nanoscale reaction zone. The CFD simulation also indicates the potentiality for simulating exothermic reaction in the nanoscale Ti/Al foil.

  6. High-pressure reactivity of L,L-lactide.

    PubMed

    Ceppatelli, Matteo; Frediani, Marco; Bini, Roberto

    2011-03-17

    L,L-Lactide, a dimer of L-lactic acid, is the typical monomer used for the catalytic synthesis of poly(L-lactic acid) (PLLA). We studied its phase diagram and reactivity at high pressure and high temperature by means of a diamond anvil cell. FTIR and Raman spectroscopy were employed to probe the changes occurring in the sample. An increase of temperature at pressure higher than 0.1 GPa revealed a solid-solid phase transition before the melting. A reaction was observed immediately after the melting with the almost complete transformation of the starting reactant to an amorphous poly(lactic acid) (PLA). The increase of pressure was found to accelerate the process, suggesting the reaction rate to be limited in the diffusion step. A steeper acceleration, likely due to multiphoton absorption processes of the 647.1 nm laser light by PLA, was observed in the Raman experiments.

  7. How fluids eat their way through rocks: Reactive-transport processes in low-permeability rocks (Invited)

    NASA Astrophysics Data System (ADS)

    Pluemper, O.

    2013-12-01

    pseudomorphically replaced by a porous product phase, where porosity development is controlled by molar volume changes and relative solubilities of the reagent and product. Porosity development in natural and experimental samples can be evaluated based on three-dimensional reconstructed volumes across reaction interfaces that are coupled with numerical simulations. Fluid-induced mineral reactions may not only produce porosity at the reaction interface during pseudomorphic replacement, but also cause fracturing due to crystal growth. Natural observations of serpentinization/carbonation in mantle rocks indicate that the associated positive solid volume change alone exerts enough stress on the surrounding rock to build up a fracture network and that the influence of external tectonic forces are not required. Through various feedbacks these systems can either become self-sustaining, when an interconnected fracture network is formed, or self-limiting due to fluid pathway obstruction. However, little is known about the positive and negative feedbacks and whether there is a fundamental difference between hydration and carbonation reactions. I will use micro- and nanostructural observations at the reaction-interface scale to provide new insight into this reactive-transport mechanism.

  8. Evaluation of high-pressure drilling fluid supply systems

    SciTech Connect

    McDonald, M.C.; Reichman, J.M.; Theimer, K.J.

    1981-10-01

    A study was undertaken to help determine the technical and economic feasibility of developing a high-pressure fluid-jet drilling system for the production of geothermal wells. Three system concepts were developed and analyzed in terms of costs, component availability, and required new-component development. These concepts included a single-conduit system that supplies the downhole cutting nozzles directly via surface-located high-pressure pumps; a single-conduit system utilizing low-pressure surface pumps to supply and operate a high-pressure downhole pump, which in turn supplies the cutting nozzles; and a dual-conduit system supplying surface-generated high-pressure fluid for cutting via one conduit and low-pressure scavenging fluid via the other. It is concluded that the single-conduit downhole pump system concept has the greatest potential for success in this application. 28 figures, 11 tables.

  9. High-water-base hydraulic fluid-irradiation experiments

    SciTech Connect

    Bradley, E.C.; Meacham, S.A.

    1981-10-01

    A remote system for shearing spent nuclear fuel assemblies is being designed under the direction of the Consolidated Fuel Reprocessing Program (CFRP). The design incorporates a dual hydraulic fluid actuation system in which only one of the fluids, a high-water-base (HWBF), would be exposed to ionizing radiation and radioactive contamination. A commercially available synthetic, solution-type HWBF was selected as the reference. Single-sample irradiation experiments were conducted with three commercial fluids over a range of irradiation exposures. The physical and chemical properties of the irradiated HWBFs were analyzed and compared with unirradiated samples. In general, the results of the analyses showed increasing degradation of fluid properties with increasing irradiation dose. The results also indicated that a synthetic solution-type HWBF would perform satisfactorily in the remote shear system where irradiation doses up to 10/sup 6/ Gy (10/sup 8/ rad) are expected.

  10. High performance magnetorheological fluids with flower-like cobalt particles

    NASA Astrophysics Data System (ADS)

    Tong, Yu; Dong, Xufeng; Qi, Min

    2017-02-01

    Recent studies indicated the electrorhological (ER) effect of the ER fluids with flower-like particles were more significant than those with traditional sphere particles, but whether the special morphology can enhance the properties of magnetorheological (MR) fluids remains unclear. To address the issue, flower-like cobalt particles (FCP) and sphere cobalt particles (SCP) were synthesized, and the properties of the two kinds of MR fluids with the two kinds of particles were compared. Particle characterization results indicate the two kinds of particles have significant difference in morphology, but little difference in crystal structure, particle size, and magnetic properties. The FCP based MR fluids (FCP-MRFs) present higher zero-field viscosity, higher field-induced yield stress, higher storage modulus and better sedimentation stability than the SCP based samples (SCP-MRFs). The high performance of the FCP-MRF can be attributed to the special morphology of the flower-like particles.

  11. Immunoanalytical characteristics of C-reactive protein and high sensitivity C-reactive protein.

    PubMed

    Moutachakkir, Mariame; Lamrani Hanchi, Asma; Baraou, Azzedine; Boukhira, Abderrahman; Chellak, Saliha

    2017-04-01

    C-reactive protein (CRP) is a polypeptide molecule belonging to the family of pentraxins. It has a molecular mass of 120,000 daltons and consists of five identical sub-units that contain each 206 amino acids. CRP is synthesized primarily by the liver in response to certain pro-inflammatory cytokines. It plays an important role in innate immunity, opsonization by its properties, complement activation and immunoglobulins receptor binding. CRP is a protein of the acute systemic inflammation and is, therefore, a prime marker of inflammation. As atherosclerosis has an inflammatory component, CRP can appreciate cardiovascular risk when analysed by more sensitive assays, that are able to measure extremely low concentrations of CRP, called high sensitivity CRP (hs-CRP). The CRP is quantified by immunonephelometry or immunoturbidimetry. There is no standard technique. The hs-CRP quantification is based on immunonephelemetry sensitized techniques called "immunolatex". We present in this paper the main biochemical and physiological data related to CRP, explaining the need for its quantification, the problems encountered in immunoassay and the interpretation of results.

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

    SciTech Connect

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

    2000-07-01

    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.

  13. Lithology, stress or pressure control of the seismicity in shale? Insights from a controlled experiment of fluid-induced fault reactivation

    NASA Astrophysics Data System (ADS)

    Rivet, D.; De Barros, L.; Daniel, G.; Guglielmi, Y.; Castilla, R.

    2015-12-01

    Shale materials are important components in petroleum systems (e.g. sealing and source rocks) and play an important role in earthquake faults. However, their mechanical behavior is still poorly understood, as it can vary from plastic to brittle. The role of fluid pressure in seismicity triggering is also not fully understood. A unique, decametric scale experiment, which aims at reactivating a natural fault by high pressure injection, was performed in shale. The injection interval was surrounded by a dense monitoring network of pressure, deformation and seismic sensors, in a well-characterized geological setting. 37 seismic events, with very small magnitude (about -4) were recorded during five series of injections within the fault zone. The spatio-temporal distribution of these events, compared with the measured displacement at the injection points, shows that most of the induced deformation is aseismic. The locations of the microseismic events are strongly asymmetrical, with most events distributed East of the fault and South of the injection area. Focal mechanisms are predominantly consistent with shear slip on a family of calcified fractures. The shale mineralogy appears to be a critical parameter governing the seismogenic character of deformation, as only calcified structures slipped seismically. As no seismic event occurs in the close vicinity of the injection, high-fluid content seems to inhibit seismic slip. Consequently, stress changes induced by this highly-pressurized volume should more likely influence the spatial distribution of seismicity. Finally, the main fault, acting as a fluid flow and/or stress barrier, strongly modifies the stress transfer. From the monitoring point of view, this experiment reflects the difficulty in quantitatively following fluid propagation in a shale formation, as seismicity will be strongly influenced by the presence of calcified fractures and by the interaction between stress transfer and lithological heterogeneities.

  14. Reactive fluid transport in CO2 reservoir caprocks: constraints from scientific drilling of a natural CO2 reservoir

    NASA Astrophysics Data System (ADS)

    Kampman, N.; Bickle, M. J.; Bertier, P.; Busch, A.; Chapman, H.; Evans, J. P.; Graham, C.; Harrington, J.; Maskell, A.

    2013-12-01

    The long-term performance of reservoir caprocks in geological CO2 storage sites remains uncertain due to the poorly constrained nature of field-scale fluid-mineral reaction kinetics and CO2 transport processes in low permeability rocks. Predicting the nature, rates and impacts of CO2 penetration into the caprocks from numerical modelling studies maybe undermined by their reliance on laboratory derived reaction kinetics from short-term experiments, and the complexity of the coupled reactive transport processes at the nano- and micro-scale. We report here on the early results from scientific drilling and laboratory analysis of the caprocks of a stacked sequence of natural CO2 reservoir at Green River, Utah. In summer 2012, diamond drilling to a depth of 325m, adjacent to a CO2 degassing normal fault recovered core from two major CO2 reservoirs in the Entrada and Navajo Sandstones and from the intervening Carmel Formation regional caprock. In-situ pH, CO2 concentrations and fluid element and isotope geochemistry were determined from wireline downhole sampling of pressurized fluids from the reservoirs. The fluid geochemistry provides important constraints on reservoir filling by flow of CO2-charged brines through the fault damage zone, macro-scale fluid flow in the reservoirs and the state of fluid-mineral thermodynamic disequilibrium from which the nature of the fluid-mineral reactions can be interpreted. Mineralogical, geochemical and petrophysical profiles through portions of the caprocks in contact with the CO2-charged reservoirs have been used to constrain the nature and penetration depths of the CO2-promoted fluid-mineral reaction fronts. The major reactions are the dissolution of diagenetic dolomite cements and hematite grain coatings which generate porosity in the caprocks. Analysis of the generated pore structure from a variety of analytical techniques will be discussed. Stable C- and O-isotopic shifts in the composition of the carbonate cements record their

  15. 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.

  16. 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.

  17. Study of fluid parameters in high pressure descaling valves

    NASA Astrophysics Data System (ADS)

    Adhikari, Param; Panta, Yogendra

    2012-11-01

    Our work is focused on the high pressure valves used for descaling purposes in steel mills. A reverse flow operation was set in one of such valves due to piping constraints. Computational approaches are being utilized to understand the fluid phenomena at such high pressures. Though the valve geometry accounts for the complete fluid flow path, a study has been initiated from an axisymmetric model of the valve core. The highly energized fluid from the descaling pump sets off a static pressure of 5000 psi at the valve inlet. It is responsible for continuous fluid flow rate of up to 208 gpm for fully open position. A Shear Stress Transport turbulence model is utilized to study pressure at nearly closed position of the poppet part while Renormalization Group Turbulence model is compared with Shear Stress Transport turbulence model for full opening position. A very low pressure developed below the poppet seat suggests the onset of cavitation zones which may lead to leakage. A full 3D model is studied after a complete studies of fluid phenomenon in the axisymmetric geometry. Using ANSYS Fluent, a commercial CFD software package, the poppet valve assembly was processed for modeling, meshing and setting up of physical parameters. Computational results show the cavitation intensities higher at small openings than at larger openings which is further verified by literature research and currently comparing with experiments.

  18. 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.

  19. Moving Overlapping Grids with Adaptive Mesh Refinement for High-Speed Reactive and Non-reactive Flow

    SciTech Connect

    Henshaw, W D; Schwendeman, D W

    2005-08-30

    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 in order to demonstrate the use and accuracy of the numerical approach.

  20. Using toughreact to model reactive fluid flow and geochemical transport in hydrothermal systems

    SciTech Connect

    Xu, Tianfu; Sonnenthal, Eric; Spycher, Nicolas; Pruess, Karsten

    2003-07-31

    The interaction between hydrothermal fluids and the rocks through which they migrate alters the earlier formed primary minerals and leads to the formation of secondary minerals, resulting in changes in the physical and chemical properties of the system. We have developed a comprehensive numerical simulator, TOUGHREACT, which considers nonisothermal multi-component chemical transport in both liquid and gas phases. A variety of subsurface thermo-physical-chemical processes is considered under a wide range of conditions of pressure, temperature, water saturation, and ionic strength. The code can be applied to problems in fundamental analysis of the hydrothermal systems and in the exploration of geothermal reservoirs including chemical evolution, mineral alteration, mineral scaling, changes of porosity and permeability, and mineral recovery from geothermal fluids.

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

    SciTech Connect

    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 and 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.

  2. Reactive fluid flow models and applications to diagenesis, mineral deposits and crustal rocks

    SciTech Connect

    Lasaga, A.C.; Rye, D.M.

    1993-08-01

    Funds are requested for a combined theoretical and field study of coupled fluid flow, heat and mass transport, and chemical reaction in hydrothermal and metamorphic systems. An existing computer code developed by the applicants which numerically treats multi-component, finite-rate reactions combined with advective and dispersive transport in one and two dimensions and which incorporates isotopic exchange and heat and mass transfer will continue to be developed and applied in a variety of geological settings. The code we have developed simultaneously solves for mass transport and reaction, thus offering a significant improvement in computational efficiency over existing ``batch`` reaction path codes. By coupling flow and chemical reaction in a hydrothermal system, we can explicitly investigate the extent to which characteristic flow-reaction paths govern the chemical evolution of the fluids in a hydrothermal system. The concept of a flow-reaction path is particularly important where certain portions of mature hydrothermal systems may exhaust the buffer capacity of the rock as the primary mineralogy is consumed. In these instances 7 fluids traversing distinct regions within the hydrothermal system may experience very different reaction histories, even where the system can be described as nearly isothermal. The study of paleo-hydrothermal systems can yield some important insights into the chemical dynamics of hydrothermal systems in general. As an example of a paleo-hydrothermal system, we have considered the geochemical evolution of ``porphyry-copper`` type mineralization.

  3. 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

  4. Dynamic high pressure: Why it makes metallic fluid hydrogen

    NASA Astrophysics Data System (ADS)

    Nellis, W. J.

    2015-09-01

    Metallic fluid H has been made by dynamic compression decades after Wigner and Huntington (WH) predicted its existence in 1935. The density at which it was made is within a few percent of the density predicted by WH. Metallic fluid H was achieved by multiple-shock compression of liquid H2, which is quasi-isentropic and thermally equilibrated. That is, the compressions were isentropic but for enough temperature and entropy to drive the crossover to completion from H2 to H at 9-fold compression. The metallic fluid is highly degenerate: T/TF≈0.014. The basic ideas of dynamic compression, also known as supersonic, adiabatic, nonlinear hydrodynamics, were developed in the last half of the Nineteenth Century in European universities. Today dynamic compression is generally unfamiliar to the scientific community, which impedes general understanding as to why fluid H becomes metallic at a pressure observable in a laboratory. The purposes of this paper are to (i) present a brief review of dynamic compression and its affects on materials, (ii) review considerations that led to the sample holder designed specifically to make metallic fluid H, and (iii) present a brief inter-comparison of dynamic and static methods to achieve high pressure relative to their prospects for making metallic H.

  5. 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.

  6. Fluoride-containing bioactive glasses: surface reactivity in simulated body fluids solutions.

    PubMed

    Lusvardi, G; Malavasi, G; Menabue, L; Aina, V; Morterra, C

    2009-11-01

    The issue of the contribution of the addition of F to glass bioactivity is not well resolved. This work reports on the surface reactivity in different solutions (DMEM and Tris) for some potentially bioactive glasses based on the composition of 45S5 glass, in which CaF(2) is substituted alternately for (part of) CaO and Na(2)O. The reactivity of F-containing glasses has been compared with that of the reference 45S5 system. The aim of this study is to explain in detail the mechanism of formation of an apatitic crystalline phase at the interface between the inorganic material and simulated biological media. A multi-technique investigation approach proposes a set of reactions involving Ca-carbonate formation, which are somewhat different from that formerly proposed by Hench for 45S5 bioactive glass, and which occur when a F-containing glass surface is in contact with a SBF. The usefulness of IR spectroscopy in recognizing the starting step of apatite (and/or FA) formation with respect to XRD technique is well established here.

  7. Fluid-fluid-solid triple point on melting curves at high temperatures

    NASA Astrophysics Data System (ADS)

    Norman, G. E.; Saitov, I. M.

    2016-11-01

    An analysis is presented of experimental data where fluid-fluid phase transitions are observed for different substances at high temperatures with triple points on melting curves. Viscosity drops point to the structural character of the transition, whereas conductivity jumps remind of both semiconductor-to-metal and plasma nature. The slope of the phase equilibrium dependencies of pressure on temperature and the consequent change of the specific volume, which follows from the Clapeyron-Clausius equation, are discussed. P(V, T) surfaces are presented and discussed for the phase transitions considered in the vicinity of the triple points. The cases of abnormal P(T) dependencies on curves of phase equilibrium are in the focus of discussion. In particular, a P(V, T) surface is presented when both fluid-fluid and melting P(T) curves are abnormal. Particular attention is paid to warm dense hydrogen and deuterium, where remarkable contradictions exist between data of different authors. The possible connection of the P(V, T) surface peculiarities with the experimental data uncertainties is outlined.

  8. Mineral formation during production of highly saline geothermal fluids

    NASA Astrophysics Data System (ADS)

    Regenspurg, S.; Naumann, R.; Feldbusch, E.; Wagner, S.; Saadat, A.

    2012-04-01

    Geothermal solutions produced from deep wells are often highly saline and of complex composition impeding exact predictions of fluid-mineral interactions. At constant (high) temperature and flow conditions during plant operation, only little precipitation would be expected. However, during the initial phase of the operation of a geothermal plant, the testing of equipment components such as pumps and valves prevents these constant fluid flow conditions. Moreover, fluid temperatures are still relatively low and vary strongly at this stage. These inhomogeneous conditions result in the precipitation of a wide range of minerals. The analysis of solutions composition as well as of the mineral precipitates during this initial testing phase represents a unique in-situ experiment allowing understanding the mineral formation from complex solutions under a wide range of temperatures. This experiment was possible at the geothermal in-situ laboratory in Groß Schönebeck (North German Basin). At this site, hot fluid (150 °C at 4400 m depth) is pumped out of a production well to the surface where it passes the above ground installation (e.g. 1 µm filter bags) before it would be re-injected into a second (injection) well. The temperature of the produced fluid varied between 10 and 100°C due to numerous turning on and shutdown phases. Fluid and filter residues have been analyzed during several cycles. In the solid phase, almost no minerals of the reservoir sandstone have been identified. Instead, several compunds have been found which precipitated directly from the solution. One group, dominated mainly by barite (BaSO4), formed as consequence of the cooling effect, which affects strongly the solubility product and results in mineral precipitation. The other group of minerals (such as magnetite or several lead minerals) form due to changes in redox conditions. These changes occur possibly in the region close to the production pump, where a strong magnetic field and highly

  9. High Operating Temperature Liquid Metal Heat Transfer Fluids (Fact Sheet)

    SciTech Connect

    Not Available

    2012-12-01

    The University of California, Los Angeles, the University of California, Berkeley, and Yale University 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.

  10. Synovial Fluid C-reactive Protein as a Diagnostic Marker for Periprosthetic Joint Infection: A Systematic Review and Meta-analysis

    PubMed Central

    Wang, Chi; Wang, Qi; Li, Rui; Duan, Jin-Yan; Wang, Cheng-Bin

    2016-01-01

    Background: Periprosthetic joint infection (PJI) is the main cause of failure following total joint arthroplasty. Until now, the diagnosis of PJI is still confronted with technical limitations, and the question of whether synovial fluid biomarker, C-reactive protein (CRP), can provide high value in the diagnosis of PJI remains unanswered and, therefore, was the aim of the study. Methods: First, we conducted a systematic review on CRP in the diagnosis of PJI by searching online databases using keywords such as “periprosthetic joint infection”, “synovial fluid”, and “C-reactive protein”. Eligible studies providing sufficient data to construct 2 × 2 contingency tables were then selected based on the list of criteria and the quality of included studies was assessed subsequently. Finally, the reported sensitivity, specificity, diagnostic odds ratio (DOR), summary receiver operating characteristic (SROC) curve, and the area under the SROC (AUSROC) were pooled together and used to evaluate overall diagnostic performance. Results: Seven studies were included in our review, six of which comprising a total of 456 participants were further investigated in our meta-analysis. The pooled sensitivity, specificity, and DOR were 0.92 (95% confidence interval [CI]: 0.86–0.96), 0.90 (95% CI: 0.87–0.93), and 101.40 (95% CI: 48.07–213.93), respectively. The AUSROC was 0.9663 (standard error, 0.0113). Conclusions: Synovial fluid CRP is a good biomarker for the diagnosis of PJI with high sensitivity and specificity. PMID:27503025

  11. Electric heating for high-temperature heat transport fluids

    NASA Astrophysics Data System (ADS)

    Holmes, J. T.

    1985-12-01

    Recent experiences with electric resistance heaters at the solar Central Receiver Test Facility are described. These heaters are used to preheat or maintain equipment used with molten nitrate salt or liquid sodium heat transfer fluids. Results of extensive testing performed to improve the reliability of similar heating systems used in the development program for the sodium-cooled liquid metal fast breeder nuclear reactor are also reviewed. Recommendations are made for increasing the reliability of trace heating systems for high-melting-point heat transfer fluids including thermal design, heating element selection, installation, insulation, and controls.

  12. 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.

  13. 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).

  14. Modeling of the Reactive High Power Impulse Magnetron Sputtering (HiPIMS) process

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Jon Tomas; Lundin, Daniel; Raadu, Michael; Brenning, Nils; Minea, Tiberiu

    2015-09-01

    Reactive high power impulse magnetron sputtering (HiPIMS) provides both a high ionization fraction of the sputtered material and a high dissociation fraction of the molecular gas. We demonstrate this through an ionization region model (IRM) of the reactive Ar/O2 HiPIMS discharge with a titanium target. We explore the influence of oxygen dilution on the discharge properties such as electron density, the ionization fraction of the sputtered vapor and the oxygen dissociation fraction. We discuss the important processes and challenges for more detailed modeling of the reactive HiPIMS discharge. Furthermore, we discuss experimental observations during reactive high power impulse magnetron sputtering sputtering (HiPIMS) of Ti target in Ar/N2 and Ar/O2 atmosphere. The discharge current waveform is highly dependent on the reactive gas flow rate, pulse repetition frequency and discharge voltage. The discharge current increases with decreasing repetition frequency and increasing flowrate of the reactive gas.

  15. High rate reactive sputtering of MoN(x) coatings

    NASA Technical Reports Server (NTRS)

    Rudnik, Paul J.; Graham, Michael E.; Sproul, William D.

    1991-01-01

    High rate reactive sputtering of MoN(x) films was performed using feedback control of the nitorgen partial pressure. Coatings were made at four different target powers: 2.5, 5.0, 7.5 and 10 kW. No hysteresis was observed in the nitrogen partial pressure vs. flow plot, as is typically seen for the Ti-N system. Four phases were determined by X-ray diffraction: molybdenum, Mo-N solid solution, Beta-Mo2N and gamma-Mo2N. The hardness of the coatings depended upon composition, substrate bias, and target power. The phases present in the hardest films differed depending upon deposition parameters. For example, the Beta-Mo2N phase was hardest (load 25 gf) at 5.0 kW with a value of 3200 kgf/sq mm, whereas the hardest coatings at 10 kW were the gamma-Mo2N phase (3000 kgf/sq mm). The deposition rate generally decreased with increasing nitrogen partial pressure, but there was a range of partial pressures where the rate was relatively constant. At a target power of 5.0 kW, for example, the deposition rates were 3300 A/min for a N2 partial pressure of 0.05 - 1.0 mTorr.

  16. Mixing enhancement for high viscous fluids in a microfluidic chamber.

    PubMed

    Wang, Shasha; Huang, Xiaoyang; Yang, Chun

    2011-06-21

    Due to small channel dimensions and laminar flows, mixing in microfluidic systems is always a challenging task, especially for high viscous fluids. Here we report a method of enhancing microfluidic mixing for high viscous fluids using acoustically induced bubbles. The bubbles can be generated in an acoustically profiled microfluidic structure by using a piezoelectric disk activated at a working frequency range between 1.5 kHz and 2 kHz. The mixing enhancement is achieved through interactions between the oscillating bubbles and fluids. Both experimental studies and numerical simulations are conducted. In the experiments, DI water-glycerol mixture solutions with various viscosities were used. The results, based on the mixing efficiency calculated from experimentally acquired fluorescent images, showed that good mixing can occur in the DI water-glycerol solutions with their maximum viscosity up to 44.75 mPa s, which to our best knowledge is the highest viscosity of fluids in microfluidic mixing experiments. To explain the mechanisms of bubble generation, the numerical simulation results show that, corresponding to the actuations at the working frequency range used in the experiment, there exists a low pressure region where the pressure is lower than the water vapor pressure in the DI water-glycerol solutions, resulting in the generation of bubbles.

  17. Creating a collimated ultrasound beam in highly attenuating fluids.

    PubMed

    Raeymaekers, Bart; Pantea, Cristian; Sinha, Dipen N

    2012-04-01

    We have devised a method, based on a parametric array concept, to create a low-frequency (300-500 kHz) collimated ultrasound beam in fluids highly attenuating to sound. This collimated beam serves as the basis for designing an ultrasound visualization system that can be used in the oil exploration industry for down-hole imaging in drilling fluids. We present the results of two different approaches to generating a collimated beam in three types of highly attenuating drilling mud. In the first approach, the drilling mud itself was used as a nonlinear mixing medium to create a parametric array. However, the short absorption length in mud limits the mixing length and, consequently, the resulting beam is weak and broad. In the second improved approach, the beam generation process was confined to a separate "frequency mixing tube" that contained an acoustically non-linear, low attenuation medium (e.g., water) that allowed establishing a usable parametric array in the mixing tube. A low-frequency collimated beam was thus created prior to its propagation into the drilling fluid. Using the latter technique, the penetration depth of the low frequency ultrasound beam in the drilling fluid was significantly extended. We also present measurements of acoustic nonlinearity in various types of drilling mud.

  18. 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.

  19. Interaction Between Hyperalkaline Fluids and Rocks Hosting Repositories for Radioactive Waste: Reactive Transport Simulations

    SciTech Connect

    Soler, Josep M.; Maeder, Urs K.

    2005-09-15

    Reactive transport calculations simulating the interaction between hyperalkaline solutions derived from the degradation of cement and potential host rocks for repositories for low- and intermediate-level radioactive waste have been performed. Two different cases are shown: (a) The example of the planned repository at Wellenberg and (b) the modeling of the GTS-HPF experiment at the Grimsel Test Site. The GIMRT code has been used for the simulations. Mineral reactions are described by kinetic rate laws. The reaction rates for the primary minerals are based on experimentally determined rates published in the literature and geometric considerations combined with measurements regarding mineral surface areas. Relatively fast rates for the secondary minerals have been used, so the results resemble the local equilibrium solution for these minerals. In both cases, the alteration of the rock and the precipitation of secondary phases cause a reduction in the permeability of the system, which would actually be beneficial for the performance of a repository. Mineral surface area controls, to a large extent, the amount of mineral alteration and the change in permeability.

  20. Assessment of reactivity transient experiments with high burnup fuel

    SciTech Connect

    Ozer, O.; Yang, R.L.; Rashid, Y.R.; Montgomery, R.O.

    1996-03-01

    A few recent experiments aimed at determining the response of high-burnup LWR fuel during a reactivity initiated accident (RIA) have raised concerns that existing failure criteria may be inappropriate for such fuel. In particular, three experiments (SPERT CDC-859, NSRR HBO-1 and CABRI REP Na-1) appear to have resulted in fuel failures at only a fraction of the anticipated enthalpy levels. In evaluating the results of such RIA simulation experiments, however, it is necessary that the following two key considerations be taken into account: (1) Are the experiments representative of conditions that LWR fuel would experience during an in-reactor RIA event? (2) Is the fuel that is being utilized in the tests representative of the present (or anticipated) population of LWR fuel? Conducting experiments under conditions that can not occur in-reactor can trigger response modes that could not take place during in-reactor operation. Similarly, using unrepresentative fuel samples for the tests will produce failure information that is of limited relevance to commercial LWR fuel. This is particularly important for high-burnup fuel since the manner under which the test samples are base-irradiated prior to the test will impact the mechanical properties of the cladding and will therefore affect the RIA response. A good example of this effect can be seen in the results of the SPERT CDC-859 test and in the NSRR JM-4 and JM-5 tests. The conditions under which the fuel used for these tests was fabricated and/or base-irradiated prior to the RIA pulse resulted in the formation of multiple cladding defects in the form of hydride blisters. When this fuel was subjected to the RIA power pulse, it failed by developing multiple cracks that were closely correlated with the locations of the pre-existing hydride blisters. In the case of the JM tests, many of the cracks formed within the blisters themselves and did not propagate beyond the heavily hydrided regions.

  1. High reactivity of ancient permafrost carbon upon hydrological release

    NASA Astrophysics Data System (ADS)

    Vonk, J. E.; Mann, P. J.; Davydov, S.; Davydova, A.; Sobczak, W. V.; Schade, J.; Bulygina, E.; Zimov, S.; Spencer, R. G. M.; Eglinton, T. I.; Holmes, R. M.

    2012-04-01

    Half of the global stock of soil organic carbon (OC) is stored in Arctic permafrost. About one third of this pool consists of so-called yedoma, organic-rich deposits that were formed during the Pleistocene. Previous studies show rapid respiration of yedoma upon thawing, with the potential release of large quantities of relict OC into the contemporary C cycle. The fluvial and coastal reactivity and fate of this OC, however, remain unclear. Duvannyi Yar is a well-studied yedoma exposure on the banks of Kolyma River in Northeastern Siberia. It can serve as a model for the >7000 km long East Siberian Arctic coastline that is dominated by similarly exposed yedoma cliffs, and is increasingly vulnerable to erosion with climate warming-induced decreases in sea-ice, and increases in storms and wave-fetch. Permafrost thaw on the Duvannyi Yar exposure produces thaw streams that are heavily loaded with freshly thawed yedoma sediments (suspended load ca. 650 g/L; particulate OC ca. 8-10 g/L; dissolved OC ca. 150-300 mg/L). We traced organic carbon loss and oxygen utilisation during incubations of Duvannyi Yar stream water, and a series of dilutions of Duvannyi Yar water and Kolyma River and East Siberian Sea water. Concurrent measurements of enzyme activities were taken to investigate the processes limitating degradation. The overall goal of the study was to investigate the relative bioavailability of contemporary versus ancient organic carbon pools over short time scales (days-weeks). Radiocarbon ages of the dissolved OC in the thaw streams were 19-29 ky BP, and particulate OC 19-38 ky BP. These ages are far older than any previously published values and clearly illustrate the mobilization of ancient permafrost organic matter into the contemporary carbon cycle. Incubation experiments showed that the ancient dissolved OC was highly susceptible to degradation, losing 34% of its carbon in 14 days (and 41% in 28 days). River and ocean water samples spiked with ancient carbon

  2. Impacts of Organic Ligands on Forsterite Reactivity in Supercritical CO2 Fluids

    SciTech Connect

    Miller, Quin R.; Kaszuba, John; Schaef, Herbert T.; Bowden, Mark E.; McGrail, B. Peter

    2015-04-07

    Subsurface injection of CO2 for enhanced hydrocarbon recovery, hydraulic fracturing of unconventional reservoirs, and geologic carbon sequestration produces a complex geochemical setting in which CO2-dominated fluids containing dissolved water and organic compounds interact with rocks and minerals. The details of these reactions are relatively unknown and benefit from additional experimentally derived data. In this study, we utilized an in situ X-ray diffraction technique to examine the carbonation reactions of forsterite (Mg2SiO4) during exposure to supercritical CO2 (scCO2) that had been equilibrated with aqueous solutions of acetate, oxalate, malonate, or citrate at 50 °C and 90 bar. The organics affected the relative abundances of the crystalline reaction products, nesquehonite (MgCO3·3H2O) and magnesite (MgCO3), likely due to enhanced dehydration of the Mg2+ cations by the organic ligands. These results also indicate that the scCO2 solvated and transported the organic ligands to the forsterite surface. This phenomenon has profound implications for mineral transformations and mass transfer in the upper crust.

  3. 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.

  4. 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.

  5. Characteristics of a magnetorheological fluid in high shear rate

    NASA Astrophysics Data System (ADS)

    Kikuchi, Takehito; Abe, Isao; Inoue, Akio; Iwasaki, Akihiko; Okada, Katsuhiko

    2016-11-01

    The information on the properties of the magnetorheological fluid (MRF) in high shear rate, in particular a shear rate greater than 10 000 s-1, is important for the design of devices utilizing the MRF with very narrow fluid gaps, which are used in high-speed applications. However, very little research has been conducted on this subject. The objective of this study is to provide such information. MRF-140CG (Lord Corp.) is chosen as an example MRF. The plastic viscosity, thermal sensitivity, and durability of the fluid, especially under a shear rate greater than 10 000 s-1, are reported. The plastic viscosity is almost constant under a wide range of magnetic input. In contrast, MRF-140CG is sensitive to the shear rate; its sensitivity is relatively low at high shear rates. The thermal sensitivity shows negative values, and the effect of temperature decreases with increasing magnetic input. According to the result of the duration test at 30 000 s-1 and at a temperature of 120 °C, the lifetime dissipation energy is 5.48 MJ ml-1.

  6. 2D fluid simulations of discharges at atmospheric pressure in reactive gas mixtures

    NASA Astrophysics Data System (ADS)

    Bourdon, Anne

    2015-09-01

    Since a few years, low-temperature atmospheric pressure discharges have received a considerable interest as they efficiently produce many reactive chemical species at a low energy cost. This potential is of great interest for a wide range of applications as plasma assisted combustion or biomedical applications. Then, in current simulations of atmospheric pressure discharges, there is the need to take into account detailed kinetic schemes. It is interesting to note that in some conditions, the kinetics of the discharge may play a role on the discharge dynamics itself. To illustrate this, we consider the case of the propagation of He-N2 discharges in long capillary tubes, studied for the development of medical devices for endoscopic applications. Simulation results put forward that the discharge dynamics and structure depend on the amount of N2 in the He-N2 mixture. In particular, as the amount of N2 admixture increases, the discharge propagation velocity in the tube increases, reaches a maximum for about 0 . 1 % of N2 and then decreases, in agreement with experiments. For applications as plasma assisted combustion with nanosecond repetitively pulsed discharges, there is the need to handle the very different timescales of the nanosecond discharge with the much longer (micro to millisecond) timescales of combustion processes. This is challenging from a computational point of view. It is also important to better understand the coupling of the plasma induced chemistry and the gas heating. To illustrate this, we present the simulation of the flame ignition in lean mixtures by a nanosecond pulsed discharge between two point electrodes. In particular, among the different discharge regimes of nanosecond repetitively pulsed discharges, a ``spark'' regime has been put forward in the experiments, with an ultra-fast local heating of the gas. For other discharge regimes, the gas heating is much weaker. We have simulated the nanosecond spark regime and have observed shock waves

  7. Geophysical evidence for fluid flow in the Laminaria High, Bonaparte basin, Northwest shelf of Australia

    NASA Astrophysics Data System (ADS)

    Abdulkareem, Lamees; Hobbs, Richard; Imber, Jonathan

    2016-04-01

    Seismic amplitude anomalies ("bright spots") can result from changes in acoustic impedance caused by the presence of fluids and/or lateral changes in lithology. In this study, 3D seismic interpretation and well log data is used to investigate the nature and causes of seismic amplitude anomalies within the shallow subsurface on the Laminaria High on the north-west shelf of Australia. Here, the anomalies are associated with active faults that cut the seabed. Previous studies suggest that fault reactivation and fault geometry have an important role in causing hydrocarbon leakage from a deeper reservoir and that bends on the larger faults will influence the localization of shear strain, increasing the risk of leakage. However, these studies did not examine the influence of fault growth during reactivation on fluid migration, or how post-rift and syn-rift sedimentation may have influenced fluid leakage. In our study, preliminary results suggest that not all active faults are associated with amplitude anomalies or dry/partially-filled hydrocarbon traps at depth, implying that there could be a different mechanism for the creation of the amplitude anomaly observed on the Laminaria High. Specifically, these anomalies may be the result of preferential cementation, or the presence of gas trapped within sediments at or near the seabed, possibly originating from gas generation due to biogenic activity in recently deposited sediment. Detailed amplitude maps are extracted from syn- and pre- faulting seismic horizons down to the top reservoir level in order to understand the spatial extent of the high amplitude anomalies within the stratigraphic succession. The first two amplitude maps for the seismic horizons beneath the seabed show high amplitude anomalies associated with the same active faults that are present on the seabed, but with some different characteristics along these faults. Then we extract number of deeper amplitude maps to the top of reservoir, to reveal whether the

  8. 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…

  9. Dissolution and reactive oxygen species generation of inhaled cemented tungsten carbide particles in artificial human lung fluids

    NASA Astrophysics Data System (ADS)

    Stefaniak, A. B.; Leonard, S. S.; Hoover, M. D.; Virji, M. A.; Day, G. A.

    2009-02-01

    Inhalation of both cobalt (Co) and tungsten carbide (WC) particles is associated with development of hard metal lung disease (HMD) via generation of reactive oxygen species (ROS), whereas Co alone is sufficient to cause asthma via solubilization and hapten formation. We characterized bulk and aerodynamically size-separated W, WC, Co, spray dryer (pre-sintered), and chamfer grinder (post-sintered) powders. ROS generation was measured in the murine RAW 264.7 cell line using electron spin resonance. When dose was normalized to surface area, hydroxyl radical generation was independent of particle size, which suggests that particle surface chemistry may be an important exposure factor. Chamfer grinder particles generated the highest levels of ROS, consistent with the hypothesis that intimate contact of metals is important for ROS generation. In artificial extracellular lung fluid, alkylbenzyldimethylammonium chloride (ABDC), added to prevent mold growth during experiments, did not influence dissolution of Co (44.0±5.2 vs. 48.3±6.4%) however, dissolution was higher (p<0.05) in the absence of phosphate (62.0±5.4 vs. 48.3±6.4%). In artificial macrophage phagolysosomal fluid, dissolution of Co (36.2±10.4%) does not appear to be influenced (p=0.30) by the absence of glycine (29.8±2.1%), phosphate (39.6±8.6%), or ABDC (44.0±10.5%). These results aid in assessing and understanding Co and W inhalation dosimetry.

  10. The effects of gas-fluid-rock interactions on CO2 injection and storage: Insights from reactive transport modeling

    SciTech Connect

    Xiao, Y.; Xu, T.; Pruess, K.

    2008-10-15

    Possible means of reducing atmospheric CO{sub 2} emissions include injecting CO{sub 2} in petroleum reservoirs for Enhanced Oil Recovery or storing CO{sub 2} in deep saline aquifers. Large-scale injection of CO{sub 2} into subsurface reservoirs would induce a complex interplay of multiphase flow, capillary trapping, dissolution, diffusion, convection, and chemical reactions that may have significant impacts on both short-term injection performance and long-term fate of CO{sub 2} storage. Reactive Transport Modeling is a promising approach that can be used to predict the spatial and temporal evolution of injected CO{sub 2} and associated gas-fluid-rock interactions. This presentation will summarize recent advances in reactive transport modeling of CO{sub 2} storage and review key technical issues on (1) the short- and long-term behavior of injected CO{sub 2} in geological formations; (2) the role of reservoir mineral heterogeneity on injection performance and storage security; (3) the effect of gas mixtures (e.g., H{sub 2}S and SO{sub 2}) on CO{sub 2} storage; and (4) the physical and chemical processes during potential leakage of CO{sub 2} from the primary storage reservoir. Simulation results suggest that CO{sub 2} trapping capacity, rate, and impact on reservoir rocks depend on primary mineral composition and injecting gas mixtures. For example, models predict that the injection of CO{sub 2} alone or co-injection with H{sub 2}S in both sandstone and carbonate reservoirs lead to acidified zones and mineral dissolution adjacent to the injection well, and carbonate precipitation and mineral trapping away from the well. Co-injection of CO{sub 2} with H{sub 2}S and in particular with SO{sub 2} causes greater formation alteration and complex sulfur mineral (alunite, anhydrite, and pyrite) trapping, sometimes at a much faster rate than previously thought. The results from Reactive Transport Modeling provide valuable insights for analyzing and assessing the dynamic

  11. Cerebrovascular reactivity alterations in asymptomatic high school football players.

    PubMed

    Svaldi, Diana O; Joshi, Chetas; Robinson, Meghan E; Shenk, Trey E; Abbas, Kausar; Nauman, Eric A; Leverenz, Larry J; Talavage, Thomas M

    2015-01-01

    Cerebrovascular reactivity (CVR) is impaired following brain injury, increasing susceptibility to subsequent injury. CVR was tracked in football and non-collision athletes throughout one season. CVR transiently decreased in football athletes during the first half of the season. Results indicate the brain adapts slowly to increases in loading, increasing risk for injury.

  12. High-resolution seismic studies applied to injected geothermal fluids

    SciTech Connect

    Smith, A.T.; Kasameyer, P.

    1985-01-01

    The application of high-resolution microseismicity studies to the problem of monitoring injected fluids is one component of the Geothermal Injection Monitoring Project at LLNL. The evaluation of microseismicity includes the development of field techniques, and the acquisition and processing of events during the initial development of a geothermal field. To achieve a specific detection threshold and location precision, design criteria are presented for seismic networks. An analysis of a small swarm near Mammoth Lakes, California, demonstrates these relationships and the usefulness of high-resolution seismic studies. A small network is currently monitoring the Mammoth-Pacific geothermal power plant at Casa Diablo as it begins production.

  13. Influence of Sex and ERK MAPK on the Pressure Reactivity Index in Newborn Piglets After Fluid Percussion Injury

    PubMed Central

    Kosty, Jennifer; Riley, John; Liang, Jiaming

    2013-01-01

    Greater impairment in autoregulation is seen in male versus female piglets following fluid percussion injury (FPI). This is partially mediated by a greater upregulation of extracellular signal-related kinase mitogen-activated protein kinase (ERK MAPK). We hypothesized that these trends would be reflected by the pressure reactivity index (PRx), a clinical measure of autoregulation. We further hypothesized that PRx values would correlate well with pial artery dilatory responses to hypotension. Male and female piglets were subjected to FPI and treated with a vehicle or ERK MAPK antagonist U 0126 (1 mg/kg IV) 30 min post-injury. FPI led to upregulation of CSF ERK MAPK in untreated piglets of both sexes, however significantly higher PRx values were seen in male versus female piglets. Following administration of U 0126, elevation of ERK MAPK levels was blocked in both sexes and PRx values were significantly improved in the male. A strong correlation was seen between the PRx and pial artery vasomotor activity. These data support previous observations that male piglets demonstrate reversible ERK MAPK-mediated impairment in autoregulation following FPI, which is reflected by the PRx. The strong correlation between the PRx and pial artery vasomotor activity supports the practice of continuously monitoring cerebrovascular autoregulation in patients using this index. PMID:23525515

  14. 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

  15. Lanthanum Titanate Nanoparticles ER Fluids with High Performance

    NASA Astrophysics Data System (ADS)

    Wang, De; Shen, Rong; Wei, Shiqiang; Lu, Kunquan

    A new type of electrorheological (ER) fluid consisting of lanthanum titanate (LTO) nanoparticles is developed. The ER fluids were prepared by suspending LTO powder in silicone oil and the particles were fabricated by wet chemical method. This ER fluid shows excellent ER properties: The static yield stress reaches over 150 kPa under 5 kV/mm with linear dependence on the applied DC electric field, and the current density is below 10 μA/cm2. In order to investigate the affect factor on the ER behavior, the LTO powder were heated under different temperatures. The ER performances of two particles treated under different temperatures were compared and the composition changes for those particles were analyzed with TG-FTIR technique. It was found that the static yield stress of the suspensions fell from over 150 kPa to about 40 kPa and the current densities decreased prominently as the rise of the heating temperature. TG-FTIR analysis indicated that polar groups remained in the particles such as alkyl group, hydroxyl group and carbonyl group etc., contribute to the ER effect significantly. The experimental results are helpful to understand the mechanism of the high ER effect and to synthesize better ER materials.

  16. High throughput assay for evaluation of reactive carbonyl scavenging capacity☆

    PubMed Central

    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. PMID:24688895

  17. Highly saline fluids from a subducting slab as the source for fluid-rich diamonds.

    PubMed

    Weiss, Yaakov; McNeill, John; Pearson, D Graham; Nowell, Geoff M; Ottley, Chris J

    2015-08-20

    The infiltration of fluids into continental lithospheric mantle is a key mechanism for controlling abrupt changes in the chemical and physical properties of the lithospheric root, as well as diamond formation, yet the origin and composition of the fluids involved are still poorly constrained. Such fluids are trapped within diamonds when they form and so diamonds provide a unique means of directly characterizing the fluids that percolate through the deep continental lithospheric mantle. Here we show a clear chemical evolutionary trend, identifying saline fluids as parental to silicic and carbonatitic deep mantle melts, in diamonds from the Northwest Territories, Canada. Fluid-rock interaction along with in situ melting cause compositional transitions, as the saline fluids traverse mixed peridotite-eclogite lithosphere. Moreover, the chemistry of the parental saline fluids--especially their strontium isotopic compositions--and the timing of host diamond formation suggest that a subducting Mesozoic plate under western North America is the source of the fluids. Our results imply a strong association between subduction, mantle metasomatism and fluid-rich diamond formation, emphasizing the importance of subduction-derived fluids in affecting the composition of the deep lithospheric mantle.

  18. 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.

  19. Effect of Suction/Injection on Unsteady Hydromagnetic Convective Flow of Reactive Viscous Fluid between Vertical Porous Plates with Thermal Diffusion

    PubMed Central

    Uwanta, I. J.; Hamza, M. M.

    2014-01-01

    An investigation is performed to study the effect of suction/injection on unsteady hydromagnetic natural convection flow of viscous reactive fluid between two vertical porous plates in the presence of thermal diffusion. The partial differential equations governing the flow have been solved numerically using semi-implicit finite-difference scheme. For steady case, analytical solutions have been derived using perturbation series method. Suction/injection is used to control the fluid flow in the channel, and an exothermic chemical reaction of Arrhenius kinetic is considered. Numerical results are presented graphically and discussed quantitatively with respect to various parameters embedded in the problem. PMID:27382632

  20. Final Report: Ionization chemistry of high temperature molecular fluids

    SciTech Connect

    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} and 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.

  1. Structural changes in supercritical fluids at high pressures

    NASA Astrophysics Data System (ADS)

    Santoro, Mario; Gorelli, Federico A.

    2008-06-01

    The structure of an archetypal model simple fluid system as argon has been investigated by x-ray diffraction at high pressures and room and high temperatures. Despite the markedly supercritical conditions (T=2 4Tc,P>102Pc) , the structure factor S(Q) is very similar, close to the melting line, to that observed in the liquid phase, thereby assessing a liquidlike structure with high atomic correlation, as proposed in a recent inelastic experiment. On the other hand, the S(Q) continuously changes upon approaching the extrapolation of the liquid-gas coexistence line in the (P/Pc,T/Tc) plane, ultimately exhibiting low atomic correlation, which reasonably indicates intermediate character between liquid and gas. The analysis of the S(Q) s based on the hard-sphere model shows that the changes are driven by the decrease in the packing fraction and the increase in the nearest-neighbor distance with decreasing pressure.

  2. Ionic Liquids and Ionizing Radiation: Reactivity of Highly Energetic Species

    SciTech Connect

    Wishart, J.F.

    2010-11-04

    Due to their unique properties, ionic liquids present many opportunities for basic research on the interactions of radiation with materials under conditions not previously available. At the same time, there are practical applied reasons for characterizing, understanding, and being able to predict how ionic-liquid-based devices and industrial-scale systems will perform under conditions of extreme reactivity, including radiation. This perspective discusses current issues in ionic liquid physical chemistry, provides a brief introduction to radiation chemistry, draws attention to some key findings in ionic liquid radiation chemistry, and identifies some current hot topics and new opportunities.

  3. Evaluation of highly reactive mono-(meth)acrylates as reactive diluents for BisGMA-based dental composites

    PubMed Central

    Kilambi, Harini; Cramer, Neil B.; Schneidewind, Lauren H.; Shah, Parag; Stansbury, Jeffrey W.; Bowman, Christopher N.

    2009-01-01

    Objective This study evaluates the performance of highly reactive novel monomethacrylates characterized by various secondary moieties as reactive diluent alternatives to TEGDMA in BisGMA filled dental resins. We hypothesize that these monomers improve material properties and kinetics over TEGDMA because of their unique polymerization behavior. Methods The cure rates and final double bond conversion of the resins were measured using real-time FTIR spectroscopy. The glass transition temperature and storage modulus of the formed polymers were measured using dynamic mechanical analysis. Flexural modulus and flexural strength values were obtained using a three-point bending flexural test carried out with a MTS® 858 Mini Bionix system. Results Polymerization kinetics and polymer mechanical properties were evaluated for the novel resin composites. It was observed that upon the use of novel monomethacrylates as reactive diluents, polymerization kinetics increased by up to 3-fold accompanied by increases in the extent of cure from 5% to 13% as compared to the BisGMA/TEGDMA control. Polymer composites formed from resins of BisGMA/novel monomethacrylates exhibited comparable Tg values to the control, along with 27–37% reductions in the glass transition half widths indicating the formation of more homogeneous polymeric networks. The BisGMA/monomethacrylate formulations exhibited equivalent flexural modulus and flexural strength values relative to BisGMA/TEGDMA. Significance Formulations containing novel monovinyl methacrylates exhibit dramatically increased curing rates while also exhibiting superior or at least comparable composite polymer mechanical properties. Thus, these types of materials are attractive for use as reactive diluent alternatives to TEGDMA in dental formulations. PMID:18584862

  4. 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.

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

    SciTech Connect

    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.

  6. System for reactivating catalysts

    SciTech Connect

    Ginosar, Daniel M.; Thompson, David N.; Anderson, Raymond P.

    2010-03-02

    A method of reactivating a catalyst, such as a solid catalyst or a liquid catalyst is provided. The method comprises providing a catalyst that is at least partially deactivated by fouling agents. The catalyst is contacted with a fluid reactivating agent that is at or above a critical point of the fluid reactivating agent and is of sufficient density to dissolve impurities. The fluid reactivating agent reacts with at least one fouling agent, releasing the at least one fouling agent from the catalyst. The at least one fouling agent becomes dissolved in the fluid reactivating agent and is subsequently separated or removed from the fluid reactivating agent so that the fluid reactivating agent may be reused. A system for reactivating a catalyst is also disclosed.

  7. Synthesis of belite cement clinker of high hydraulic reactivity

    SciTech Connect

    Kacimi, Larbi Simon-Masseron, Angelique Salem, Souria Ghomari, Abdelhamid Derriche, Zoubir

    2009-07-15

    This study is concerned with the increase of the cooling rate of belite clinker, by using the water quenching for the chemical stabilization of reactive belite, which improves the hydraulic properties of this clinker. The addition of adequate mineralizers, as NaF and Fe{sub 2}O{sub 3}, contributes to the improvement of the clinker properties obtained at low burning temperature. X-ray fluorescence spectroscopy, X-ray diffraction analysis and optical microscopy were used to determine the chemical and mineralogical compositions of this clinker. The samples were analyzed by means of a scanning electronic microscope connected with an energy-dispersive X-ray spectrometer to detect the composition of the belite phase and its morphology. Physical and mechanical properties of this clinker cement were determined. The results show that the belite clinker obtained at 1150 {sup o}C, with lime saturation factor 0.67, is characterized by a great hydraulic reactivity, similar to that of the ordinary alite clinker. The addition of 2% of NaF and the water quenching improved the chemical, mineralogical and structural properties, while improving the cement hydraulic properties.

  8. 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.

    2001-01-01

    A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime (about 40 ps), high frequency (about 5G hz), high power bursts of low-duty factor microwaves sufficient to generate a dielectric barrier discharge and passing a gas to treated through the discharge so as to cause dissociative reduction of the exhaust gases. The invention also includes a reactor for generating the non-thermal plasma.

  9. Fluid-loss control for high-permeability rocks in hydraulic fracturing under realistic shear conditions

    SciTech Connect

    Navarrete, R.C.; Mitchell, J.P.

    1995-12-31

    A study is presented on the effectiveness of different combinations of fluid and fluid-loss additives to control fluid loss in high-permeability formations under high shear rates. The impact on matrix damage and proppant-pack damage is also studied. Borate-crosslinked guars, hydroxyethylcellulose (HEC) and a surfactant water-base gravel packing fluid were investigated. The fluid-loss additive considered was silica flour. All fluid-loss tests were run in dynamic fluid-loss cells. To properly test high-permeability cores, new long core dynamic fluid-loss cells were used. The matrix damage caused by the invasion of the fluid was determined using pressure taps along the core. Conductivity tests were also run to determine the damage to the proppant pack. Results show that the effectiveness of particulate fluid-loss additives under dynamic conditions is strongly dependent on the initial leakoff rate, which depends on the pressure gradient across the core, permeability of the core and viscosity of the invading fluid. The use of silica flour helps matrix flowback, and it has a minimal effect on proppant-pack conductivity in clean fluids (e.g., surfactant water-base gravel packing fluid). With the exception of the borate-crosslinked guar with no fluid-loss additive, the variety of fluids used in these tests (with and without silica flour) have a negligible effect on postproduction.

  10. High Order Accuracy Methods for Supersonic Reactive Flows

    DTIC Science & Technology

    2008-06-25

    bubble interactions [12], the supersonic cavity flows [11], and etc. The difficulty of implement - ing the spectral method to these complex fluid...enhance the convergence properties of the approximation via a filter function σ(η) [30] with the following properties σ(η)= σ(−η), σ(±1) = 0, σ(0)= 1, σ... implementation of the Hybrid method depends on the ability to obtain accurate information on the smoothness of a function . In this work, we employ the Multi

  11. 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.

  12. Characteristics of high quality sorbent for fluidized bed combustion and problems of maintaining uniform reactivity

    SciTech Connect

    Bain, R.J. . Dept. of Geology)

    1993-03-01

    Fluidized bed combustion of coal is considered one of the more promising clean coal technologies for the future. While much research has gone into the design and operation of FBC units, there is little concern for what characterizes a high quality sorbent and the source of such a sorbent. Carbonate rocks, limestone and dolomite, have been tested extensively as sorbents and primarily two rock characteristics appear to significantly control reactivity: composition and texture. Calcium carbonate is more reactive than magnesium carbonate where all other rock characteristics are the same. In considering texture, highest reactivity is measured for carbonate rocks which consist of homogeneous, euhedral crystals ranging in size from .05 to .2 mm and which possess uniform intercrystalline porosity. The most reactive material possesses both high calcium content, uniform microcrystalline texture and intercrystalline porosity, however, such material is not very abundant in nature and is not locally available to midcontinent facilities. Sucrosic dolomite, which possesses uniform microcrystalline texture and intercrystalline porosity has high rank reactivity. While this rock is quite common, it occurs as beds, generally less than twenty feet thick, interlayered with less reactive dolomite types. Therefore, without selective quarrying methods, production of sorbent with uniformly high reactivity will be impossible.

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

    SciTech Connect

    Sjoewall, Christopher; Askendal, Agneta; Almroth, Gunnel

    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 efficiently 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.

  14. Granular activated carbon adsorption and fluid-bed reactivation at Manchester, New Hampshire. Final report Mar 77-Apr 82

    SciTech Connect

    Kittredge, D.; Beaurivage, R.; Paris, D.

    1983-10-01

    Treatment performances of virgin and reactivated GAC were evaluated during three reactivation-exhaustion cycles by measuring total organic carbon (TOC), trihalomethanes (THM), and trihalomethane formation potential (THMFP). GAC adsorptive capacity was measured using traditional test parameters including iodine number, molasses decolorizing index, BET, and pore-size distribution. The GAC was reactivated on-site by a 500 lb/hr fluidized-bed unit. Results of this study demonstrated that onsite reactivation was a cost-effective method of restoring the adsorptive properties of spent GAC. During a 10-month period, more than 1.8 million lb of GAC was reactivated at a total cost of less than 22 cents/lb as compared with a delivered cost of 61.5 cents/lb for virgin GAC. The average total carbon loss resulting from transportation and reactivation was 11.5% by volume.

  15. 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.

  16. Human antibody responses after dengue virus infection are highly cross-reactive to Zika virus

    PubMed Central

    Priyamvada, Lalita; Quicke, Kendra M.; Hudson, William H.; Onlamoon, Nattawat; Sewatanon, Jaturong; Edupuganti, Srilatha; Pattanapanyasat, Kovit; Chokephaibulkit, Kulkanya; Mulligan, Mark J.; Wilson, Patrick C.; Ahmed, Rafi; Suthar, Mehul S.; Wrammert, Jens

    2016-01-01

    Zika virus (ZIKV) is an emerging mosquito-borne flavivirus of significant public health concern. ZIKV shares a high degree of sequence and structural homology compared with other flaviviruses, including dengue virus (DENV), resulting in immunological cross-reactivity. Improving our current understanding of the extent and characteristics of this immunological cross-reactivity is important, as ZIKV is presently circulating in areas that are highly endemic for dengue. To assess the magnitude and functional quality of cross-reactive immune responses between these closely related viruses, we tested acute and convalescent sera from nine Thai patients with PCR-confirmed DENV infection against ZIKV. All of the sera tested were cross-reactive with ZIKV, both in binding and in neutralization. To deconstruct the observed serum cross-reactivity in depth, we also characterized a panel of DENV-specific plasmablast-derived monoclonal antibodies (mAbs) for activity against ZIKV. Nearly half of the 47 DENV-reactive mAbs studied bound to both whole ZIKV virion and ZIKV lysate, of which a subset also neutralized ZIKV. In addition, both sera and mAbs from the dengue-infected patients enhanced ZIKV infection of Fc gamma receptor (FcγR)-bearing cells in vitro. Taken together, these findings suggest that preexisting immunity to DENV may impact protective immune responses against ZIKV. In addition, the extensive cross-reactivity may have implications for ZIKV virulence and disease severity in DENV-experienced populations. PMID:27354515

  17. Subsurface Multiphase Flow and Multicomponent Reactive Transport Modeling using High-Performance Computing

    SciTech Connect

    Hammond, Glenn E.; Lichtner, Peter C.; Lu, Chuan

    2007-08-01

    Numerical modeling has become a critical tool to the Department of Energy for evaluating the environmental impact of alternative energy sources and remediation strategies for legacy waste sites. Unfortunately, the physical and chemical complexity of many sites overwhelms the capabilities of even most “state of the art” groundwater models. Of particular concern are the representation of highly-heterogeneous stratified rock/soil layers in the subsurface and the biological and geochemical interactions of chemical species within multiple fluid phases. Clearly, there is a need for higher-resolution modeling (i.e. more spatial, temporal, and chemical degrees of freedom) and increasingly mechanistic descriptions of subsurface physicochemical processes. We present research being performed in the development of PFLOTRAN, a parallel multiphase flow and multicomponent reactive transport model. Written in Fortran90, PFLOTRAN is founded upon PETSc data structures and solvers and has exhibited impressive strong scalability on up to 4000 processors on the ORNL Cray XT3. We are employing PFLOTRAN in the simulation of uranium transport at the Hanford 300 Area, a contaminated site of major concern to the Department of Energy, the State of Washington, and other government agencies where overly-simplistic historical modeling erroneously predicted decade removal times for uranium by ambient groundwater flow. By leveraging the billions of degrees of freedom available through high-performance computation using tens of thousands of processors, we can better characterize the release of uranium into groundwater and its subsequent transport to the Columbia River, and thereby better understand and evaluate the effectiveness of various proposed remediation strategies.

  18. Static reactive power compensators for high-voltage power systems. Final report

    SciTech Connect

    Not Available

    1981-04-01

    A study conducted to summarize the role of static reactive power compensators for high voltage power system applications is described. This information should be useful to the utility system planning engineer in applying static var systems (SVS) to high voltage as (HVAC) systems. The static var system is defined as a form of reactive power compensator. The general need for reactive power compensation in HVAC systems is discussed, and the static var system is compared to other devices utilized to provide reactive power compensation. Examples are presented of applying SVS for specific functions, such as the prevention of voltage collapse. The operating principles of commercially available SVS's are discussed in detail. The perormance and active power loss characteristics of SVS types are compared.

  19. The application of high frequency seismic monitoring methods for the mapping of fluid injections

    SciTech Connect

    Majer, E.L.

    1987-04-01

    This paper describes experimental work using seismic methods for monitoring the path of fluid injections. The most obvious application is the high pressure fluid injections for the purpose of hydrofracturing. Other applications are the injection of grout into shallow subsurface structures and the disposal of fluids in the geothermal and toxic waste industries. In this paper hydrofracture monitoring and grout injections will be discussed.

  20. Development of chiral metal amides as highly reactive catalysts for asymmetric [3 + 2] cycloadditions

    PubMed Central

    Yamashita, Yasuhiro; Yoshimoto, Susumu; Dutton, Mark J

    2016-01-01

    Summary Highly efficient catalytic asymmetric [3 + 2] cycloadditions using a chiral copper amide are reported. Compared with the chiral CuOTf/Et3N system, the CuHMDS system showed higher reactivity, and the desired reactions proceeded in high yields and high selectivities with catalyst loadings as low as 0.01 mol %. PMID:27559396

  1. Dynamic high pressure: why it makes metallic fluid hydrogen

    NASA Astrophysics Data System (ADS)

    Nellis, William

    2015-06-01

    Metallic fluid H (MFH) was made by dynamic compression decades after Wigner and Huntington (WH) predicted it in 1935. The density of MFH is within a few percent of the density predicted by WH. MFH was made by multiple-shock compression of liquid H2, which process is quasi-isentropic and thermally equilibrated. The compressions were isentropic but produced enough dissipation as temperature T and entropy S to drive the crossover from insulating H2 to metallic H at 9-fold compressed atomic H density. T and S were tuned by temporally shaping the applied pressure pulse such that H2 dissociated to H at sufficiently high density to make a highly degenerate metal. The basic ideas of dynamic compression, also known as supersonic, adiabatic, nonlinear hydrodynamics, were developed in the last half of the Nineteenth Century. Our purposes are to (i) present a brief review of dynamic compression and its affects on materials, (ii) review considerations that led to the sample holder designed specifically to make MFH, and (iii) present a inter-comparison of dynamic and static methods relative to their prospects for making metallic H.

  2. High-order computational fluid dynamics tools for aircraft design

    PubMed Central

    Wang, Z. J.

    2014-01-01

    Most forecasts predict an annual airline traffic growth rate between 4.5 and 5% in the foreseeable future. To sustain that growth, the environmental impact of aircraft cannot be ignored. Future aircraft must have much better fuel economy, dramatically less greenhouse gas emissions and noise, in addition to better performance. Many technical breakthroughs must take place to achieve the aggressive environmental goals set up by governments in North America and Europe. One of these breakthroughs will be physics-based, highly accurate and efficient computational fluid dynamics and aeroacoustics tools capable of predicting complex flows over the entire flight envelope and through an aircraft engine, and computing aircraft noise. Some of these flows are dominated by unsteady vortices of disparate scales, often highly turbulent, and they call for higher-order methods. As these tools will be integral components of a multi-disciplinary optimization environment, they must be efficient to impact design. Ultimately, the accuracy, efficiency, robustness, scalability and geometric flexibility will determine which methods will be adopted in the design process. This article explores these aspects and identifies pacing items. PMID:25024419

  3. Comparison of C-reactive protein and high-sensitivity C-reactive protein levels in patients on hemodialysis.

    PubMed

    Helal, Imed; Zerelli, Lilia; Krid, Madiha; ElYounsi, Fethi; Ben Maiz, Hedi; Zouari, Bechir; Adelmoula, Jaouida; Kheder, Adel

    2012-05-01

    Chronic inflammation is highly prevalent in patients on hemodialysis (HD), as evidenced by increased levels of C-reactive protein (CRP). We compared CRP to high-sensitivity C-reactive protein (hs-CRP) to determine whether it has any clinical implications and prognostic significance in terms of mortality. CRP was measured using a standard immunoturbidometric assay on the COBAS® INTEGRA system and hs-CRP was measured using the Dade Behring on the Konelab Nephelometer in 50 patients on HD. CRP (≥6 mg/L) and hs-CRP (≥3 mg/L) levels were elevated in 30% and 54% of the patients, respectively. A significant correlation was noted between hs-CRP and CRP levels (r = 0.98, P <0.001). Deming regression analysis showed that the slope was near one (r = 0.90; 0.83-0.94) and that the intercept was small. Multivariate regression confirmed that age above 40 years (RR = 3.69, P = 0.027) and duration on HD greater than five years (RR = 3.71, P = 0.028) remained significant independent predictors of serum hs-CRP. Thirteen patients died during follow-up (26%). Multivariate Cox regression demonstrated that hs-CRP (RR = 1.062, P = 0.03) and CRP levels (RR = 1.057, P = 0.009) and age (RR = 1.078, P = 0.001) were the most powerful predictors of mortality. The CRP standard assay presents a reasonable alternative to the hs-CRP assay in patients on HD. The advantages of the CRP standard assay are its online and real-time availability as well as lower costs, particularly in developing countries.

  4. Activated Metal Oxide Surfaces as Highly Reactive Environments

    DTIC Science & Technology

    1990-08-03

    underway. " Synthesis of Ultra-High Surface Area Fe203 by Precipitation Methods Yong-Xi Li A series of precipitations of Fe(OH) 3 (from FeCl 3) at...Progress was also made on developing new aerogel procedures for synthesis of ultra-high surface area magnesium oxide. Finally,’ome metal oxide molecules...were studied in chemical reactions and by theoretical methods .-) Three students earned Ph.D. degrees and one an M.S. degree. A visiting professor and

  5. Implications of an ultramafic body in a basalt-dominated oceanic hydrothermal system on the vent fluid composition and on processes within sediments overlying a hydrothermal discharge zone: results of reactive-transport modeling

    NASA Astrophysics Data System (ADS)

    Alt-Epping, P.; Diamond, L. W.

    2009-04-01

    characterized by elevated H2(aq), SiO2(aq), H2S(aq) and a relatively low pH. If the discharge zone is covered by sediments, the infiltrating hydrothermal fluid mixes with the sediment pore-water and entrained seawater and the presence of H2(aq) initiates a series of redox processes such as the reduction of CO2 to CH4 and SO4-2 to H2S. Thus, mixing-induced redox processes involving H2 and SO4-2 provide a mechanism to form metal sulfides and potentially ore deposits. Furthermore, the presence of H2(aq) in the ascending fluid favors the stability of the low-sulfidation form of redox-sensitive minerals, such as pyrrhotite over pyrite. The sediments mark the transition zone that separates the hot, anoxic, low pH hydrothermal basement fluids from the cold, oxic, high pH seawater. Mixing between oxygenated seawater and/or the sediment porewater and the reduced, discharging H2, H2S and CH4-enriched hydrothermal fluid may provide conditions favorable for microbial chemosynthesis and an environment suitable for the growth of microorganisms. However, as the lherzolite becomes progressively altered the reactivity of its primary minerals decreases and hence the production of H2 declines. The decrease in reactivity of the ultramafic is enhanced by the hydrological sealing which is caused by the volume increase of the rock and by the corresponding porosity/permeability reduction associated with serpentinization. The decreasing H2 production changes the oxidation state of the discharging fluid and gradually leads to chemical fingerprints that are consistent with purely basaltic systems. Numerical studies of this type demonstrate that reactive transport simulations are useful in correlating observable changes in chemical parameters (i.e. the composition of the vent fluid or alteration of the sediment column overlying discharge zones) with processes that occur in regions of the system that are not easily accessible by direct seafloor exploration.

  6. Carbonated hydroxyapatite starting from calcite and different orthophosphates under moderate hydrothermal conditions: Synthesis and surface reactivity in simulated body fluid

    SciTech Connect

    Pham Minh, Doan Nzihou, Ange; Sharrock, Patrick

    2014-12-15

    Highlights: • Carbonated apatite (CAP) could be easily obtained from CaCO{sub 3} and orthophosphates. • Highest CaCO{sub 3} dissolution and apatitic carbonate content were obtained with H{sub 3}PO{sub 4}. • A-B-type CAP was formed. • The synthesized CAP was thermally stable up to 1000 °C. • This CAP showed high biomineralization activity before and after thermal treatment. - Abstract: The one-step synthesis of carbonated hydroxyapatite (CAP) using calcite and different orthophosphates was investigated in a closed batch reactor. Only orthophosphoric acid could lead to the complete decomposition of calcite particles, when the reaction temperature was set at 80 °C. On the other hand, the reaction time and the dilution of the initial calcite suspension had no significant influence on the formation of the solid products. CAP was formed as the main crystalline calcium phosphate with the carbonate content in the range of 4.2–4.6 wt.%. The thermal decarbonation of the synthesized CAP started at 750 °C but it was only significant at 1000 °C under air atmosphere. This thermal decarbonation was total at 1200 °C or above. All CAP samples and products following thermal treatments were found bioactive in the test using simulated body fluid (SBF) solution.

  7. 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

  8. 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

    SciTech Connect

    Fakcharoenphol, Perapon; Xiong, Yi; Hu, Litang; Winterfeld, Philip H.; Xu, Tianfu; Wu, Yu-Shu

    2013-05-01

    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 transport 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 fractured media.

  9. The importance of narcissism in predicting proactive and reactive aggression in moderately to highly aggressive children.

    PubMed

    Barry, Tammy D; Thompson, Alice; Barry, Christopher T; Lochman, John E; Adler, Kristy; Hill, Kwoneathia

    2007-01-01

    The present study examined the importance of psychopathy-linked narcissism in predicting proactive and reactive aggression and conduct problems in a group of 160 moderately to highly aggressive children (mean age of 10 years, 9 months). Children's self-report of self-esteem and parent and teacher report of dimensions of psychopathy [narcissism, callous-unemotional (CU) traits, and impulsivity], proactive and reactive aggression, and conduct problems were collected. Composites of parent and teacher ratings of children's behavior were used. Consistent with the study's hypotheses, narcissism predicted unique variance in both proactive and reactive aggression, even when controlling for other dimensions of psychopathy, demographic variables associated with narcissism, and the alternative subtype of aggression. As hypothesized, impulsivity was significantly associated with only reactive aggression. CU traits were not related to proactive or reactive aggression once the control variables were entered. All dimensions of psychopathy predicted unique variance in conduct problems. Consistent with prediction, narcissism was not significantly related to general self-esteem, providing support that narcissism and self-esteem are different constructs. Furthermore, narcissism and self-esteem related differentially to proactive aggression, reactive aggression, and conduct problems. Furthermore, narcissism but not self-esteem accounted for unique variance in aggression and conduct problems. The importance of narcissism in the prediction of aggressive behaviors and clinical implications are discussed.

  10. Fault structure, stress, or pressure control of the seismicity in shale? Insights from a controlled experiment of fluid-induced fault reactivation

    NASA Astrophysics Data System (ADS)

    De Barros, Louis; Daniel, Guillaume; Guglielmi, Yves; Rivet, Diane; Caron, Hervé; Payre, Xavier; Bergery, Guillaume; Henry, Pierre; Castilla, Raymi; Dick, Pierre; Barbieri, Ernesto; Gourlay, Maxime

    2016-06-01

    Clay formations are present in reservoirs and earthquake faults, but questions remain on their mechanical behavior, as they can vary from ductile (aseismic) to brittle (seismic). An experiment, at a scale of 10 m, aims to reactivate a natural fault by fluid pressure in shale materials. The injection area was surrounded by a dense monitoring network comprising pressure, deformation, and seismicity sensors, in a well-characterized geological setting. Thirty-two microseismic events were recorded during several injection phases in five different locations within the fault zone. Their computed magnitude ranged between -4.3 and -3.7. Their spatiotemporal distribution, compared with the measured displacement at the injection points, shows that most of the deformation induced by the injection is aseismic. Whether the seismicity is controlled by the fault architecture, mineralogy of fracture filling, fluid, and/or stress state is then discussed. The fault damage zone architecture and mineralogy are of crucial importance, as seismic slip mainly localizes on the sealed-with-calcite fractures which predominate in the fault damage zone. As no seismicity is observed in the close vicinity of the injection areas, the presence of fluid seems to prevent seismic slips. The fault core acts as an impermeable hydraulic barrier that favors fluid confinement and pressurization. Therefore, the seismic behavior seems to be strongly sensitive to the structural heterogeneity (including permeability) of the fault zone, which leads to a heterogeneous stress response to the pressurized volume.

  11. High fluid intake increases urine free cortisol excretion in normal subjects.

    PubMed

    Mericq, M V; Cutler, G B

    1998-02-01

    To test the hypothesis that increased fluid intake increases the urine free cortisol, we prescribed 5 liters of fluid intake per day or a normal fluid intake according to a randomized cross-over design in six normal volunteers. Each period lasted 5 days, with a 2-day washout period of normal fluid intake between the two periods. Urine free cortisol, 17-hydroxycorticosteroids, and creatinine were measured daily during each study period, and the average value over each 5-day period was calculated for each subject. High fluid intake caused a significant increase in the mean urine free cortisol [126 +/- 33 (SD) vs. 77 +/- 18 micrograms/day, P < 0.005]. The frequency of urine free cortisol results that exceeded the upper normal limit of 95 micrograms/day was also much higher during high fluid intake (23/30 vs. 6/30, P < 0.005). By contrast, urine 17-hydroxycorticosteroids (high fluid vs. normal fluid: 5.3 +/- 1.5 vs. 5.0 +/- 1.7 mg/day, respectively, P = not significant) and urine creatinine (1.51 +/- 0.48 vs. 1.45 +/- 0.37 g/day, P = not significant) did not differ between the two study periods. We conclude that high fluid intake (5 liters/day) increases free cortisol excretion without an increase in urine 17-hydroxycorticosteroids. Thus, mild to moderate increases in urine cortisol excretion may not indicate hypercortisolism in individuals who have a high fluid intake and urine volume.

  12. Premixed direct injection nozzle for highly reactive fuels

    DOEpatents

    Ziminsky, Willy Steve; Johnson, Thomas Edward; Lacy, Benjamin Paul; York, William David; Uhm, Jong Ho; Zuo, Baifang

    2013-09-24

    A fuel/air mixing tube for use in a fuel/air mixing tube bundle is provided. The fuel/air mixing tube includes an outer tube wall extending axially along a tube axis between an inlet end and an exit end, the outer tube wall having a thickness extending between an inner tube surface having a inner diameter and an outer tube surface having an outer tube diameter. The tube further includes at least one fuel injection hole having a fuel injection hole diameter extending through the outer tube wall, the fuel injection hole having an injection angle relative to the tube axis. The invention provides good fuel air mixing with low combustion generated NOx and low flow pressure loss translating to a high gas turbine efficiency, that is durable, and resistant to flame holding and flash back.

  13. Trace elements in migrating high-temperature fluids: Effects of diffusive exchange with the adjoining solid

    NASA Technical Reports Server (NTRS)

    Kenyon, Patricia M.

    1993-01-01

    Trace element concentrations and isotopic ratios are frequently used to study the behavior of high-temperature fluids in both metamorphic and igneous systems. Many theoretical formulations of the effects of fluid migration on trace elements have assumed instantaneous reequilibration between the migrating fluid and the solid material through which it is passing. This paper investigates the additional effects which arise when equilibration is not instantaneous due to a limited rate of diffusion in the solid, using an analytical steady state solution to a set of partial differential equations describing the exchange of trace elements between the fluid and the solid during the migration of the fluid.

  14. Impact reactivity of materials at very high oxygen pressure

    NASA Technical Reports Server (NTRS)

    Connor, H. W.; Minchey, J. G.; Crowder, R.; Davidson, R.

    1983-01-01

    The requirements for impact testing of materials in an oxygen atmosphere at pressures from 82.7 MPa (12,000 psi) to 172 MPa (25,000 psi) were evaluated. The impact tester system was evaluated for potential pressure increases from 69 MPa (10,000 psi) to 82.7 MPa (12,000 psi). The low pressure oxygen and nitrogen systems, the impact tower, the impact test cell, and the high pressure oxygen system were evaluated individually. Although the structural integrity of the impact test cell and the compressor were sufficient for operation at 82.7 MPa (12,000 psi), studies revealed possible material incompatibility at that pressure and above. It was recommended that if a component should be replaced for 82.7 MPa (12,000 psi) operation the replacement should meet the final objectives of 172 MPa (25,000 psi). Recommended changes in the system include; use of Monel 400 for pressures above 82.7 MPa (12,000 psi), use of bellows to replace the seal in the impact tester, use of a sapphire window attached to a fiber optic for event sensing, and use of a three diaphragm compressor.

  15. Protein-reactive, thermoresponsive copolymers with high flexibility and biodegradability.

    PubMed

    Guan, Jianjun; Hong, Yi; Ma, Zuwei; Wagner, William R

    2008-04-01

    A family of injectable, biodegradable, and thermosensitive copolymers based on N-isopropylacrylamide, acrylic acid, N-acryloxysuccinimide, and a macromer polylactide-hydroxyethyl methacrylate were synthesized by free radical polymerization. Copolymers were injectable at or below room temperature and formed robust hydrogels at 37 degrees C. The effects of monomer ratio, polylactide length, and AAc content on the chemical and physical properties of the hydrogel were investigated. Copolymers exhibited lower critical solution temperatures (LCSTs) from 18 to 26 degrees C. After complete hydrolysis, hydrogels were soluble in phosphate buffered saline at 37 degrees C with LCSTs above 40.8 degrees C. Incorporation of type I collagen at varying mass fractions by covalent reaction with the copolymer backbone slightly increased LCSTs. Water content was 32-80% without collagen and increased to 230% with collagen at 37 degrees C. Hydrogels were highly flexible and relatively strong at 37 degrees C, with tensile strengths from 0.3 to 1.1 MPa and elongations at break from 344 to 1841% depending on NIPAAm/HEMAPLA ratio, AAc content, and polylactide length. Increasing the collagen content decreased both elongation at break and tensile strength. Hydrogel weight loss at 37 degrees C was 85-96% over 21 days and varied with polylactide content. Hydrogel weight loss at 37 degrees C was 85-96% over 21 days and varied with polylactide content. Degradation products were shown to be noncytotoxic. Cell adhesion on the hydrogels was 30% of that for tissue culture polystyrene but increased to statistically approximate this control surface after collagen incorporation. These newly described thermoresponsive copolymers demonstrated attractive properties to serve as cell or pharmaceutical delivery vehicles for a variety of tissue engineering applications.

  16. THE HIGH TEMPERATURE CHEMICAL REACTIVITY OF LI2O

    SciTech Connect

    Kessinger, G.; Missimer, D.

    2009-11-13

    ) It is likely that some or all of the past high temperature phase behavior and vaporization experiments involving Li{sub 2}O(s) at temperatures above 1250 C have actually involved Li{sub 2}O(l). If these past measurements were actually measurements performed on Li{sub 2}O(l) instead of the solid, the thermochemical data for phases and species in the Li-O system will require reevaluation.

  17. 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

  18. 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...

  19. Solubility of Aragonite in Aqueous Fluids at High Pressure and High Temperature

    NASA Astrophysics Data System (ADS)

    Facq, Sébastien; Daniel, Isabelle; Petitgirard, Sylvain; Cardon, Hervé; Sverjensky, Dimitri

    2014-05-01

    Deep crustal and mantle aqueous fluids play a crucial role in geologic processes occurring in the Earth's interior, especially at high PT conditions. Dissolved carbon appears to be a major element constituting these aqueous fluids, occurring under the form of molecular species (CO2, CO, CH4), ionic species such as carbonate or bicarbonate ions or some more complex organic compounds [1]. However, the nature and the content of the chemical species constituting these C-bearing aqueous fluids may strongly be affected by the environmental geologic conditions such as the pressure and the temperature range. If fluid speciation and solubility of carbonate minerals are well characterized at HT and relatively low pressure, less is evident at pressure above 2 GPa where experimental challenges make trickier speciation and solubility measurements. Thanks to recent advances in theoretical aqueous geochemistry [1-3], combined experimental and theoretical efforts allow now the investigation of speciation and solubility of carbonate minerals with pure water at higher PT conditions than previously feasible [4]. However, direct measurements of solubility of carbonate minerals at HP-HT conditions are still needed to help to the development of quantitative models of carbon transport by aqueous fluids in subduction zones and validate existing aqueous speciation model. In this study, we present recent X-ray fluorescence measurements and thermodynamic model of solubility of carbonate in aqueous fluids at pressure up to 5 GPa. The amount of dissolved aragonite in the fluid has been measured from the intensity of the Ca K-lines at the ESRF-ID27 using an externally-heated membrane-type diamond anvil cell and an incident monochromatic focused X-Ray beam at 20 keV. The combination of the XRF data on dissolution of CaCO3mineral combined to previous speciation results permits now to calculate the solubility KS of aragonite a pressure in excess of 2 GPa. [1] Manning, C. E. et al., Review in

  20. Properties of planetary fluids at high shock pressures and temperatures

    SciTech Connect

    Nellis, W.J.; Mitchell, A.C.; Holmes, N.C.; McCandless, P.C.

    1991-03-01

    Models of the interiors of Uranus and Neptune are discussed. Pressures and temperatures in the interiors can be achieved in representative constituent molecular fluids by shock compression. Experimental techniques are described and recent results for synthetic Uranus and hydrogen are discussed. 19 refs., 4 figs., 1 tab.

  1. Flowmeter measures flow rates of high temperature fluids

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1966-01-01

    Flowmeter in which flow rate is determined by measuring the position and thus the displacement of an internal float acted upon by the flowing fluid determines the flow rates of various liquid metals at elevated temperatures. Viscous forces cause the float to move from its mounted position, affording several means for measuring this motion and the flow rate.

  2. Novel Characteristics of Multifunctional Fluid Filters Fabricated by High-Energy Synchrotron Radiation Lithography

    NASA Astrophysics Data System (ADS)

    Ukita, Yosiaki; Asano, Toshifumi; Fujiwara, Kuniyo; Yokoyama, Takuya; Matsui, Katsuhiro; Takeo, Masahiro; Negoro, Seiji; Saiki, Tsunemasa; Utsumi, Yuichi

    2006-09-01

    A new method using multifunctional fluid filters with through-capillary arrays for high throughput and large-scale integrated microfluidics is proposed. The method utilizes a liquid’s surface tension and fluid flows perpendicular to a substrate using a fluid filter. Utilizing this method, we can minimize the space consumption of microchannels, and enhance the flexibility of channel design, because these are not extant on the surface of substrates as in traditional microfluidics, but are through-capillary arrays passing through the substrates. In addition, the passive multifunctional characteristics of the fluid filter are favorable for the integration of microfluidics. Therefore, the integration number can be increased from the previous order of hundreds to thousands or more. We conducted a computational fluid dynamics (CFD) analysis to examine the feasibility of vertical fluid flow operation; the multifunctionality of the fluid filter as a microvalve, a microchannel and a micromixer was estimated. The fabrication of the fluid filter by deep X-ray lithography and the vertical fluid flow operation were successfully conducted and the high-throughput properties of the vertical fluid flow were demonstrated.

  3. The chemical and mechanical behaviors of polymer / reactive metal systems under high strain rates

    NASA Astrophysics Data System (ADS)

    Shen, Yubin

    As one category of energetic materials, impact-initiated reactive materials are able to release a high amount of stored chemical energy under high strain rate impact loading, and are used extensively in civil and military applications. In general, polymers are introduced as binder materials to trap the reactive metal powders inside, and also act as an oxidizing agent for the metal ingredient. Since critical attention has been paid on the metal / metal reaction, only a few types of polymer / reactive metal interactions have been studied in the literature. With the higher requirement of materials resistant to different thermal and mechanical environments, the understanding and characterization of polymer / reactive metal interactions are in great demand. In this study, PTFE (Polytetrafluoroethylene) 7A / Ti (Titanium) composites were studied under high strain rates by utilizing the Taylor impact and SHPB tests. Taylor impact tests with different impact velocities, sample dimensions and sample configurations were conducted on the composite, equipped with a high-speed camera for tracking transient images during the sudden process. SHPB and Instron tests were carried out to obtain the stress vs. strain curves of the composite under a wide range of strain rates, the result of which were also utilized for fitting the constitutive relations of the composite based on the modified Johnson-Cook strength model. Thermal analyses by DTA tests under different flow rates accompanied with XRD identification were conducted to study the reaction mechanism between PTFE 7A and Ti when only heat was provided. Numerical simulations on Taylor impact tests and microstructural deformations were also performed to validate the constitutive model built for the composite system, and to investigate the possible reaction mechanism between two components. The results obtained from the high strain rate tests, thermal analyses and numerical simulations were combined to provide a systematic study on

  4. 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.

  5. Graphene oxide as a high-performance fluid-loss-control additive in water-based drilling fluids.

    PubMed

    Kosynkin, Dmitry V; Ceriotti, Gabriel; Wilson, Kurt C; Lomeda, Jay R; Scorsone, Jason T; Patel, Arvind D; Friedheim, James E; Tour, James M

    2012-01-01

    Graphene oxide (GO) performs well as a filtration additive in water-based drilling fluids at concentrations as low as 0.2 % (w/w) by carbon content. Standard American Petroleum Institute (API) filtration tests were conducted on pH-adjusted, aqueous dispersions of GO and xanthan gum. It was found that a combination of large-flake GO and powdered GO in a 3:1 ratio performed best in the API tests, allowing an average fluid loss of 6.1 mL over 30 min and leaving a filter cake ~20 μm thick. In comparison, a standard suspension (~12 g/L) of clays and polymers used in the oil industry gave an average fluid loss of 7.2 mL and a filter cake ~280 μm thick. Scanning electron microscopy imaging revealed the extreme pliability of well-exfoliated GO, as the pressure due to filtration crumpled single GO sheets, forcing them to slide through pores with diameters much smaller than the flake's flattened size. GO solutions also exhibited greater shear thinning and higher temperature stability compared to clay-based fluid-loss additives, demonstrating potential for high-temperature well applications.

  6. Design rules for pumping and metering of highly viscous fluids in microfluidics.

    PubMed

    Perry, Sarah L; Higdon, Jonathan J L; Kenis, Paul J A

    2010-11-21

    The use of fluids that are significantly more viscous than water in microfluidics has been limited due to their high resistance to flow in microscale channels. This paper reports a theoretical treatment for the flow of highly viscous fluids in deforming microfluidic channels, particularly with respect to transient effects, and discusses the implications of these effects on the design of appropriate microfluidic devices for highly viscous fluids. We couple theory describing flow in a deforming channel with design equations, both for steady-state flows and for the transient periods associated with the initial deformation and final relaxation of a channel. The results of this analysis allow us to describe these systems and also to assess the significance of different parameters on various deformation and/or transient effects. To exemplify their utility, we apply these design rules to two applications: (i) pumping highly viscous fluids for a nanolitre scale mixing application and (ii) precise metering of fluids in microfluidics.

  7. 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.

  8. Antidepressant treatment differentially affects the phenotype of high and low stress reactive mice.

    PubMed

    Surget, Alexandre; Van Nieuwenhuijzen, Petra S; Heinzmann, Jan-Michael; Knapman, Alana; McIlwrick, Silja; Westphal, Willy-Paul; Touma, Chadi; Belzung, Catherine

    2016-11-01

    Modelling key endophenotypes can be a powerful approach to gain insight into mechanisms underlying the aetiology and pathophysiology of neuropsychiatric disorders. Based on evidence of stress hormone system dysregulations in depression, the Stress Reactivity (SR) mouse model has been generated by a selective breeding approach for extremes in HPA axis reactivity, resulting in high (HR), intermediate (IR) and low (LR) reactive mice. The characterisation of their phenotypic alterations has highlighted many similarities of HR and LR mice with the melancholic and atypical depression, respectively. We therefore aimed to examine whether the antidepressant fluoxetine (10 mg/kg/day i.p., 4-5 weeks) can ameliorate the phenotypic characteristics of HR and LR mice in neuroendocrine functions (HPA axis basal activity, stress reactivity, negative feedback), emotional reactivity/coping-strategy (open field, forced swim tests), spatial learning/memory (Morris water-maze) and hippocampal neurogenesis. Line differences in HPA axis reactivity were maintained under fluoxetine treatment. However, we observed fluoxetine effects on glucocorticoid-induced negative feedback, stress-coping behaviours, cognitive functions and neurogenesis. Specifically, our results revealed line-dependent consequences of fluoxetine treatment: (1) an amelioration of the 'melancholic-like' features of HR mice (reversing the negative feedback resistance, the hyperactive coping style and the memory deficits; increasing hippocampal neurogenesis); (2) an exacerbation of the phenotypic deviations of LR mice (increasing their pronounced negative feedback and passive coping style). Thus, these findings support the predictive validity of antidepressant treatment in the HR mouse line and emphasize the translational value of the SR mouse model for the development of therapeutic strategies based on endophenotype-driven classifications.

  9. High-yield reactivation of anionic tobacco peroxidase overexpressed in Escherichia coli.

    PubMed

    Zakharova, G S; Poloznikov, A A; Chubar, T A; Gazaryan, I G; Tishkov, V I

    2015-09-01

    Anionic tobacco peroxidase (TOP) is extremely active in chemiluminescence reaction of luminol oxidation without addition of enhancers and more stable than horseradish peroxidase under antibody conjugation conditions. In addition, recombinant TOP (rTOP) produced in Escherichia coli is known to be a perfect direct electron transfer catalyst on electrodes of various origin. These features make the task of development of a high-yield reactivation protocol for rTOP practically important. Previous attempts to reactivate the enzyme from E. coli inclusion bodies were successful, but the reported reactivation yield was only 14%. In this work, we thoroughly screened the refolding conditions for dilution protocol and compared it with gel-filtration chromatography. The impressive reactivation yield in the dilution protocol (85%) was achieved for 8 μg/mL solubilized rTOP protein and the refolding medium containing 0.3 mM oxidized glutathione, 0.05 mM dithiothreitol, 5 mM CaCl2, 5% glycerol in 50 mM Tris-HCl buffer, pH 9.6, with 1 μM hemin added at the 24th hour of incubation. A practically important discovery was a 30-40% increase in the reactivation yield upon delayed addition of hemin. The reactivation yield achieved is one of the highest reported in the literature on protein refolding by dilution. The final yield of purified active non-glycosylated rTOP was ca. 60 mg per L of E. coli culture, close to the yield reported before for tomato and tobacco plants overexpressing glycosylated TOP (60 mg/kg biomass) and much higher than for the previously reported refolding protocol (2.6 mg per L of E. coli culture).

  10. Formation and reactivity of surface-bound high oxidation state Ruthenium-oxo complexes.

    SciTech Connect

    Hornstein, B. J.; Dattelbaum, D. M.; Schoonover, J. R.; Meyer, T. J.

    2004-01-01

    Ruthenium polypyridyl oxalate complexes are precursors to high oxidation state species that can catalyze the oxidation of a variety of substrates. Covalent attachment of these reactive species to surfaces such at ZrO{sub 2} or TiO{sub 2} inhibit catalyst deactivation and provide supports from which to build electrocatalytic and photoelectrocatalytic devices. Unfortunately, few details of the effects of surface binding on reactivity are available in the literature. To this end, precursors such as, Ru(H{sub 2}O{sub 3}Ptpy)(C{sub 2}O{sub 4})(H{sub 2}O) and (C{sub 2}O{sub 4})(H{sub 2}O{sub 3}Ptpy)Ru-O-Ru(H{sub 2}O{sub 3}Ptpy)(C{sub 2}O{sub 4}) (tpy is terpyridine) have been synthesized and attached to TiO{sub 2}. Quantitative surface binding studies were carried out and acid catalyzed solvolysis was used to form the aqua species. The complexes were oxidized with Ce(IV) to their high-valent analogs and their reactivity toward selected substrates was tested. These studies not only provide information about the effects of surface binding on the reactivity of metal oxides but also have implications for the development of light-driven catalysts.

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

    SciTech Connect

    Xu, Yan; Wei, Yanli; Fang, Xin; Li, Fangxing; Azim, Riyasat

    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 is 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.

  12. 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

  13. Structure, Dynamics and Reactivity of C-O-H Fluids in Nanoporous Regimes Relevant to Unconventional Reservoirs

    NASA Astrophysics Data System (ADS)

    Cole, D. R.; Gautam, S.

    2015-12-01

    Many unconventional reservoir lithologies are comprised of pore regimes ranging from relatively uncommon large macropores at the millimeter scale to more numerous small micropores at the sub-micron and nanometer scale. The size, distribution and connectivity of these confined geometries, the chemistry of the solid, the chemistry of the fluids and their physical properties collectively dictate how fluids migrate into and through these micro- and nano-environments, wet and ultimately react with the solid surfaces. Our current understanding of the rates and mechanisms of fluid and mass transport and interaction within these multiporosity systems at the molecular scale is far less robust than we would like. This presentation will take a two-fold approach to this topic area. First we will provide a brief overview on pore types and their relationship with mineralogy in key gas shale formations with special emphasis on the Utica/Pt. Pleasant and Eagle Ford. We will highlight results from conventional methods such as SEM along with more sophisticated approaches including small- and ultra-small angle neutron scattering that contribute to two key science question areas: (a) What are the size, distribution, connectedness, and contribution to total porosity of nano- to micropores in representative gas shales? and (b) How do these pore features vary with the distributions of clay and carbonate matrix and organic matter? The second more in-depth part of the presentation will focus the application of state-of-the-art experimental, analytical and computational tools to assess key features of the fluid-matrix interaction relevant to shale settings. The multidisciplinary approaches highlighted will include neutron scattering and NMR experiments, thermodynamic measurements and molecular-level simulations to quantitatively assess molecular properties of pure water, aqueous electrolytes and simple immiscible water-hydrocarbon mixtures confined to well-characterized porous media

  14. High expression of CD26 accurately identifies human bacteria-reactive MR1-restricted MAIT cells

    PubMed Central

    Sharma, Prabhat K; Wong, Emily B; Napier, Ruth J; Bishai, William R; Ndung'u, Thumbi; Kasprowicz, Victoria O; Lewinsohn, Deborah A; Lewinsohn, David M; Gold, Marielle C

    2015-01-01

    Mucosa-associated invariant T (MAIT) cells express the semi-invariant T-cell receptor TRAV1–2 and detect a range of bacteria and fungi through the MHC-like molecule MR1. However, knowledge of the function and phenotype of bacteria-reactive MR1-restricted TRAV1–2+ MAIT cells from human blood is limited. We broadly characterized the function of MR1-restricted MAIT cells in response to bacteria-infected targets and defined a phenotypic panel to identify these cells in the circulation. We demonstrated that bacteria-reactive MR1-restricted T cells shared effector functions of cytolytic effector CD8+ T cells. By analysing an extensive panel of phenotypic markers, we determined that CD26 and CD161 were most strongly associated with these T cells. Using FACS to sort phenotypically defined CD8+ subsets we demonstrated that high expression of CD26 on CD8+ TRAV1–2+ cells identified with high specificity and sensitivity, bacteria-reactive MR1-restricted T cells from human blood. CD161hi was also specific for but lacked sensitivity in identifying all bacteria-reactive MR1-restricted T cells, some of which were CD161dim. Using cell surface expression of CD8, TRAV1–2, and CD26hi in the absence of stimulation we confirm that bacteria-reactive T cells are lacking in the blood of individuals with active tuberculosis and are restored in the blood of individuals undergoing treatment for tuberculosis. PMID:25752900

  15. High expression of CD26 accurately identifies human bacteria-reactive MR1-restricted MAIT cells.

    PubMed

    Sharma, Prabhat K; Wong, Emily B; Napier, Ruth J; Bishai, William R; Ndung'u, Thumbi; Kasprowicz, Victoria O; Lewinsohn, Deborah A; Lewinsohn, David M; Gold, Marielle C

    2015-07-01

    Mucosa-associated invariant T (MAIT) cells express the semi-invariant T-cell receptor TRAV1-2 and detect a range of bacteria and fungi through the MHC-like molecule MR1. However, knowledge of the function and phenotype of bacteria-reactive MR1-restricted TRAV1-2(+) MAIT cells from human blood is limited. We broadly characterized the function of MR1-restricted MAIT cells in response to bacteria-infected targets and defined a phenotypic panel to identify these cells in the circulation. We demonstrated that bacteria-reactive MR1-restricted T cells shared effector functions of cytolytic effector CD8(+) T cells. By analysing an extensive panel of phenotypic markers, we determined that CD26 and CD161 were most strongly associated with these T cells. Using FACS to sort phenotypically defined CD8(+) subsets we demonstrated that high expression of CD26 on CD8(+)  TRAV1-2(+) cells identified with high specificity and sensitivity, bacteria-reactive MR1-restricted T cells from human blood. CD161(hi) was also specific for but lacked sensitivity in identifying all bacteria-reactive MR1-restricted T cells, some of which were CD161(dim) . Using cell surface expression of CD8, TRAV1-2, and CD26(hi) in the absence of stimulation we confirm that bacteria-reactive T cells are lacking in the blood of individuals with active tuberculosis and are restored in the blood of individuals undergoing treatment for tuberculosis.

  16. Optical Doppler tomographic imaging of fluid flow velocity in highly scattering media

    SciTech Connect

    Chen, Z.; Milner, T.E.; Dave, D.; Nelson, J.S.

    1997-01-01

    An optical Doppler tomography (ODT) system that permits imaging of fluid flow velocity in highly scattering media is described. ODT combines Doppler velocimetry with the high spatial resolution of low-coherence optical interferometry to measure fluid flow velocity at discrete spatial locations. Tomographic imaging of particle flow velocity within a circular conduit submerged 1mm below the surface in a highly scattering phantom of Intralipid is demonstrated. {copyright} {ital 1997} {ital Optical Society of America}

  17. Violent offenders respond to provocations with high amygdala and striatal reactivity.

    PubMed

    da Cunha-Bang, Sofi; MacDonald Fisher, Patrick; Vadskjær Hjordt, Liv; Perfalk, Erik; Persson Skibsted, Anine; Bock, Camilla; Ohlhues Baandrup, Anders; Deen Christensen, Marie; Thomsen, Carsten; Sestoft, Dorte; Knudsen, Gitte M

    2017-03-08

    The ability to successfully suppress impulses and angry affect is fundamental to control aggressive reactions following provocations. The aim of this study was to examine neural responses to provocations and aggression using a laboratory model of reactive aggression. We used a novel functional magnetic resonance imaging point-subtraction aggression paradigm in 44 men, of whom 18 were incarcerated violent offenders and 26 were control non-offenders. We measured brain activation following provocations (monetary subtractions), while the subjects had the possibility to behave aggressively or pursue monetary rewards. The violent offenders behaved more aggressively than controls (aggression frequency 150 vs. 84, p = 0.03) and showed significantly higher brain reactivity to provocations within the amygdala and striatum, as well as reduced amygdala-prefrontal and striato-prefrontal connectivity. Amygdala reactivity to provocations was positively correlated with task-related behavior in the violent offenders. Across groups, striatal and prefrontal reactivity to provocations were positively associated with trait anger and trait aggression. These results suggest that violent individuals display abnormally high neural sensitivity to social provocations, a sensitivity related to aggressive behavior. These findings provide novel insight into the neural pathways that are sensitive to provocations, which is critical to more effectively shape interventions that aim to reduce pathological aggressive behavior.

  18. High pressure induced phase transition and superdiffusion in anomalous fluid confined in flexible nanopores

    SciTech Connect

    Bordin, José Rafael; Krott, Leandro B. Barbosa, Marcia C.

    2014-10-14

    The behavior of a confined spherical symmetric anomalous fluid under high external pressure was studied with Molecular Dynamics simulations. The fluid is modeled by a core-softened potential with two characteristic length scales, which in bulk reproduces the dynamical, thermodynamical, and structural anomalous behavior observed for water and other anomalous fluids. Our findings show that this system has a superdiffusion regime for sufficient high pressure and low temperature. As well, our results indicate that this superdiffusive regime is strongly related with the fluid structural properties and the superdiffusion to diffusion transition is a first order phase transition. We show how the simulation time and statistics are important to obtain the correct dynamical behavior of the confined fluid. Our results are discussed on the basis of the two length scales.

  19. Mathematical Analysis of Strong Fluid Mechanical Effects at High Mach Number in Reactive and Nonreactive Flow

    DTIC Science & Technology

    1992-05-12

    following papers with at least partial support by this research grant: 1. (with M. Avellaneda ) "Stieltjes integral representation and effective...mechanisms for initiation of reacting shock waves", SIAM J. Sci. Stat. Comput., Vol. 11, No. 5, pp. 950-974, September 1990 7. (with M. Avellaneda ...A. Majda, pp. 217-238, 1990 9. (with M. Avellaneda ) Homogenization and Renormalization of Multiple-Scattering Expansions for Green Functions in

  20. 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.

  1. High-Resolution Single-Molecule Fluorescence Imaging of Zeolite Aggregates within Real-Life Fluid Catalytic Cracking Particles**

    PubMed Central

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

    2015-01-01

    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. PMID:25504139

  2. Development of Concentration-Dependent Diffusion Instability in Reactive Miscible Fluids Under Influence of Constant or Variable Inertia

    NASA Astrophysics Data System (ADS)

    Bratsun, Dmitry A.; Stepkina, Olga S.; Kostarev, Konstantin G.; Mizev, Alexey I.; Mosheva, Elena A.

    2016-12-01

    In this work, we focus on the processes which accompany a frontal neutralization reaction occurring between two miscible fluids filling a vertical Hele-Shaw cell. We have found that chemically-induced changes of reagent concentrations coupled with concentration- dependent diffusion (CDD) can produce spatially localized low density areas which are sensitive to the external inertial field. In the case of static gravity we have demonstrated both experimentally and theoretically that it can give rise to the development of perfectly periodic convective structure. This scenario is strikingly different from the irregular density fingering, which is typically observed in the miscible systems. When the system is under the influence of the periodic low-frequency vibrations perpendicular to the reaction front, we found numerically the excitation of a mixed-mode instability combining the double-diffusion instabilities and the Rayleigh-Taylor mechanism of the convection within the low density areas.

  3. Use of TOUGHREACT to Simulate Effects of Fluid Chemistry onInjectivity in Fractured Geothermal Reservoirs with High Ionic StrengthFluids

    SciTech Connect

    Xu, Tianfu; Zhang, Guoxiang; Pruess, Karsten

    2005-02-09

    Recent studies suggest that mineral dissolution/precipitation and clay swelling effects could have a major impact on the performance of hot dry rock (HDR) and hot fractured rock (HFR) reservoirs. A major concern is achieving and maintaining adequate injectivity, while avoiding the development of preferential short-circuiting flow paths. A Pitzer ionic interaction model has been introduced into the publicly available TOUGHREACT code for solving non-isothermal multi-phase reactive geochemical transport problems under conditions of high ionic strength, expected in typical HDR and HFR systems. To explore chemically-induced effects of fluid circulation in these systems, we examine ways in which the chemical composition of reinjected waters can be modified to improve reservoir performance. We performed a number of coupled thermo-hydrologic-chemical simulations in which the fractured medium was represented by a one-dimensional MINC model (multiple interacting continua). Results obtained with the Pitzer activity coefficient model were compared with those using an extended Debye-Hueckel equation. Our simulations show that non-ideal activity effects can be significant even at modest ionic strength, and can have major impacts on permeability evolution in injection-production systems. Alteration of injection water chemistry, for example by dilution with fresh water, can greatly alter precipitation and dissolution effects, and can offer a powerful tool for operating hot dry rock and hot fractured rock reservoirs in a sustainable manner.

  4. 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.

  5. Duty cycle control in reactive high-power impulse magnetron sputtering of hafnium and niobium

    NASA Astrophysics Data System (ADS)

    Ganesan, R.; Treverrow, B.; Murdoch, B.; Xie, D.; Ross, A. E.; Partridge, J. G.; Falconer, I. S.; McCulloch, D. G.; McKenzie, D. R.; Bilek, M. M. M.

    2016-06-01

    Instabilities in reactive sputtering have technological consequences and have been attributed to the formation of a compound layer on the target surface (‘poisoning’). Here we demonstrate how the duty cycle of high power impulse magnetron sputtering (HiPIMS) can be used to control the surface conditions of Hf and Nb targets. Variations in the time resolved target current characteristics as a function of duty cycle were attributed to gas rarefaction and to the degree of poisoning of the target surface. As the operation transitions from Ar driven sputtering to metal driven sputtering, the secondary electron emission changes and reduces the target current. The target surface transitions smoothly from a poisoned state at low duty cycles to a quasi-metallic state at high duty cycles. Appropriate selection of duty cycle increases the deposition rate, eliminates the need for active regulation of oxygen flow and enables stable reactive deposition of stoichiometric metal oxide films. A model is presented for the reactive HIPIMS process in which the target operates in a partially poisoned mode with different degrees of oxide layer distribution on its surface that depends on the duty cycle. Finally, we show that by tuning the pulse characteristics, the refractive indices of the metal oxides can be controlled without increasing the absorption coefficients, a result important for the fabrication of optical multilayer stacks.

  6. Highly reactive, liquid diacrylamides via synergistic combination of spatially arranged curing moieties

    PubMed Central

    Maier, Maximilian; Schmidt, Magnus S; Ringwald, Markus

    2017-01-01

    Six polymerizable N,N’-diacylamides containing spatially arranged N-acryl, N-allyl and/or N-alkyl groups were prepared via two-step syntheses and characterized by 1H/13C NMR-spectra, refractive index (RI) and viscosity measurements. Photo DSC measurements on activated samples provided reactivity parameters ∆H p, R p,max and t max, while FTIR spectra before and after curing elucidated the underlying polymerization mechanism. Mechanical testing of the obtained polymers exhibited gradual differences in network densities, depending on the intramolecular arrangement and number of functional groups. Overall, a general building principle for highly reactive, liquid diacrylamides via synergistic combination of optimally arranged functional groups could be identified. The highest possible level of intramolecular synergism was found for low viscous N,N'-diacryloyl-N,N'-diallyl-1,4-but-2-enediamine. PMID:28382175

  7. 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.

  8. 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

  9. Nanometer scale high-aspect-ratio trench etching at controllable angles using ballistic reactive ion etching

    SciTech Connect

    Cybart, Shane; Roediger, Peter; Ulin-Avila, Erick; Wu, Stephen; Wong, Travis; Dynes, Robert

    2012-11-30

    We demonstrate a low pressure reactive ion etching process capable of patterning nanometer scale angled sidewalls and three dimensional structures in photoresist. At low pressure the plasma has a large dark space region where the etchant ions have very large highly-directional mean free paths. Mounting the sample entirely within this dark space allows for etching at angles relative to the cathode with minimal undercutting, resulting in high-aspect ratio nanometer scale angled features. By reversing the initial angle and performing a second etch we create three-dimensional mask profiles.

  10. Role of high-sensitivity C-reactive protein measurements in HIV patients

    PubMed Central

    Vishwanath, Arun; Quaiser, Saif; Khan, Ruhi

    2016-01-01

    As we herald into the 21st century, the quality of life and the repertoire of highly active antiretroviral therapy (HAART) have considerably improved. However, considerable work is still needed to educate the population about primary and secondary prevention modalities. Moreover, regular monitoring of immune response with patients on HAART with conventional biomarkers is still a problem in low resource settings which needs to be addressed. We aim to review high-sensitivity C-reactive protein as a potential biomarker in this regard. PMID:27890944

  11. Implications of perennial saline springs for abnormally high fluid pressures and active thrusting in western California

    SciTech Connect

    Unruh, J.R.; Davisson, M.L.; Criss, R.E.; Moores, E.M. )

    1992-05-01

    Perennial saline springs in the Rumsey Hills area, southwestern Sacramento Valley, California, locally discharge at high elevations and near ridgetops. The springs are cold, are commonly associated with natural gas seeps, and typically emerge along west-vergent thrust faults. Stable isotope analyses indicate that the spring waters are similar to oil-field formation fluids and they have had a significant residence time in the subsurface at moderate temperatures. The nonmeteoric character of the springs demonstrates that they are not being fed by perched water tables. The authors propose that these subsurface formation waters are being forced to the surface by anomalously high porefluid pressures. The Rumsey Hills area is one of Quaternary uplift, thrusting, and crustal shortening, and prospect wells drilled there have encountered anomalously high fluid pressures at shallow depths. They attribute these high fluid pressures to active tectonic compression and shortening of Cretaceous marine sedimentary rocks. The widespread occurrence of anomalously high pore-fluid pressures and perennial saline springs in the Coast Ranges and western Great Valley suggests that much of western California may be characterized as a seismically active, overpressured thrust belt. The emergence of formation waters along thrust faults further suggests that patterns of subsurface fluid flow in western California may be similar to those in overpressured accretionary prisms, and that excess fluid pressures may also play a role in the distribution of seismicity.

  12. 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.

  13. 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.

  14. Experimental Study on Fluid Distribution at Ultra-High Metamorphic Conditions

    NASA Astrophysics Data System (ADS)

    Mönicke, K.; Burchard, M.; Duyster, J.; Maresch, W. V.; Röller, K.; Stöckhert, B.

    2001-12-01

    Ultra-high pressure (UHP) metamorphic rocks record deep subduction of continental crust. Insight into their rheological behavior at UHP metamorphic conditions is important for the understanding of the mechanical state and the kinematics within subduction zones. Amazingly, many exhumed UHP metamorphic rocks do not show evidence of significant deformation. Thus, it has been proposed that deformation is localized in low-strength zones controlled by partially wetting interstitial fluids [1]. Experimental results [2] show that at UHP metamorphic conditions only one homogenous fluid phase with variable composition exists, whose density and viscosity should be intermediate between those of conventional aqueous solutions and hydrous melts. Inclusions of such supercritical fluid have been recently described from a natural UHP metamorphic rock [3]. Motivated by these findings, experiments using a piston-cylinder apparatus were performed to study the fluid distribution in various rock types at pressures of 3.5 GPa and temperatures between 900 ° C and 600 ° C. Starting materials were natural UHP metamorphic specimens of (1) S-type granitic biotite-phengite-gneiss and (2) pyrope-quartzite, both from the Dora Maira Massif (Western Alps, Italy) and (3) a diamond-bearing garnet-mica-gneiss with granodioritic bulk composition from the Saxonian Erzgebirge (Germany), all with 2 wt.% water added. The supercritical fluids formed in these experiments can be quenched to form a silicic glass with demixing of an aqueous solution without changing the UHP fluid topology significantly. The shape of the fluid-filled interstices is irregular and complex, resulting in a low volume/interface area ratio and a potential of high stress concentration at the edges of wedge-shaped offshoots. We propose that the distribution of supercritical fluids has a pronounced effect on the strength of cool subducted crust, allowing deformation by grain boundary sliding and dissolution precipitation creep, or

  15. 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.

  16. Retrograde methane-dominated fluid inclusions from high-temperature granulites of Rogaland, southwestern Norway

    SciTech Connect

    Van Den Kerkhof, A.M. ); Touret, J.L.R. ); Maijer, C.; Jansen, J.B.H. )

    1991-09-01

    Non-aqueous inclusions in the high-grade (800-1,000C; 4kbar) metamorphic Rogaland region, southwestern Norway, consist of mixtures of CO{sub 2}-CH{sub 4}-N{sub 2}. In particular the fluid inclusions in quartz veins in migmatites are characterized by high CH{sub 4} concentrations and they were re-equilibrated at temperatures below 500C during isobaric cooling. Observations by microthermometry demonstrated several complicated sequences of phase transitions, including partial and metastable homogenization (at lower temperature than melting), and S-L or S-V transitions. The phase behavior reflects a wide variation in composition and molar volume. Fluid compositions were measured by Raman microspectrometry. By this method, also small amounts of graphite have been detected in CO{sub 2}-CH{sub 4} inclusions. The instantaneous formation of graphite in a CO{sub 2}-CH{sub 4} inclusion by induction of the argon laser beam has been observed which points to the metastability of the CO{sub 2}-CH{sub 4} mixture. The calculated densities of the observed fluid mixtures are relatively low, necessitating a revision of the earlier interpretation of these inclusions as containing pure high-density fluids. Inclusions in quartz, trapped after the peak of metamorphism, record fluid heterogeneity which may present evidence for fluid-deficient metamorphism during the retrograde M2-M3 metamorphism.

  17. High-speed tomographic PIV and OH PLIF measurements in turbulent reactive flows

    NASA Astrophysics Data System (ADS)

    Coriton, Bruno; Steinberg, Adam M.; Frank, Jonathan H.

    2014-06-01

    High-speed tomographic particle image velocimetry (TPIV) is demonstrated in turbulent reactive flows at acquisition rates ranging from 10 to 16 kHz. The 10-kHz TPIV measurements are combined with planar laser-induced fluorescence (PLIF) imaging of OH to mark the high-temperature reaction zone of the flame. Simultaneous TPIV/OH PLIF measurements are applied to the stabilization region of a weakly turbulent lifted dimethyl ether (DME)/air jet flame ( Re D = 7,600) and the mixing layer of a turbulent partially premixed DME/air jet flame ( Re D = 29,300). In the lifted jet flame, vortical structures exhibit time-dependent morphological changes and eventually dissipate as they approach the flame. In the near field of the turbulent jet flame, dynamics of localized extinction are captured as coherent structures with high compressive strain rates interact with the reaction zone and subsequently break apart. The principal axis of compressive strain has a strong preferential orientation at 45° with respect to the jet axis. The three-dimensional velocity field measurements are used to evaluate biases in two-dimensional (2D) measurements of compressive strain rates in a turbulent jet flame. The biases in the 2D measurements primarily stem from out-of-plane orientation of the principal axis of compressive strain. Comparisons with a constant density turbulent non-reactive jet ( Re D = 22,600) show that the jet flame has larger coherent structures that are confined near the reaction zone. Data from the non-reactive jet are also used to evaluate effects of noise, bias, and spatial averaging on measurements of the velocity and velocity gradients.

  18. Highly potent soluble amyloid-β seeds in human Alzheimer brain but not cerebrospinal fluid

    PubMed Central

    Kaeser, Stephan A.; Maia, Luis F.; Portelius, Erik; Pinotsi, Dorothea; Kaminski, Clemens F.; Winkler, David T.; Maetzler, Walter; Keyvani, Kathy; Spitzer, Philipp; Wiltfang, Jens; Kaminski Schierle, Gabriele S.; Zetterberg, Henrik; Staufenbiel, Matthias; Jucker, Mathias

    2017-01-01

    The soluble fraction of brain samples from patients with Alzheimer’s disease contains highly biologically active amyloid-β seeds. In this study, we sought to assess the potency of soluble amyloid-β seeds derived from the brain and cerebrospinal fluid. Soluble Alzheimer’s disease brain extracts were serially diluted and then injected into the hippocampus of young, APP transgenic mice. Eight months later, seeded amyloid-β deposition was evident even when the hippocampus received subattomole amounts of brain-derived amyloid-β. In contrast, cerebrospinal fluid from patients with Alzheimer’s disease, which contained more than 10-fold higher levels of amyloid-β peptide than the most concentrated soluble brain extracts, did not induce detectable seeding activity in vivo. Similarly, cerebrospinal fluid from aged APP-transgenic donor mice failed to induce cerebral amyloid-β deposition. In comparison to the soluble brain fraction, cerebrospinal fluid largely lacked N-terminally truncated amyloid-β species and exhibited smaller amyloid-β-positive particles, features that may contribute to the lack of in vivo seeding by cerebrospinal fluid. Interestingly, the same cerebrospinal fluid showed at least some seeding activity in an in vitro assay. The present results indicate that the biological seeding activity of soluble amyloid-β species is orders of magnitude greater in brain extracts than in the cerebrospinal fluid. PMID:25212850

  19. Relationship between airway reactivity induced by methacholine or ultrasonically nebulized distilled cold water and BAL fluid cellular constituents in patients with sulfur mustard gas-induced asthma.

    PubMed

    Emad, Ali; Emad, Yasaman

    2007-01-01

    The objective of this article was to evaluate the relationship between the bronchial reactivity to methacholine and distilled cold water and inflammatory bronchial alveolar lavage (BAL) cells in mustard gas-induced asthma. This was a randomized, crossover clinical study set in a university hospital. The patients were 17 veterans with mustard gas-induced asthma and 17 normal veterans as a control group. Inhalation challenges with ultrasonically nebulized distilled water and methacholine and BAL via bronchoscopy and were performed in all patients and subjects. All patients did sustain a 20% fall in FEV(1) after methacholine, whereas two of them did not with distilled cold water. The patients were sensitive to distilled cold water with a median PD20 of 8.44 +/- 6.55 mL and sensitive to methacholine with the median PC20 of 4.88 +/- 4.22 mg/mL. Significant correlation was found between PC20 of methacholine and PD20 of distilled cold water (r = -0.74, p = 0.005). The proportion of BAL macrophages was significantly lower in patients with asthma than in the control group (p = 0.001). The proportions of lymphocytes and neutrophils were similar in the two groups. The percentage of eosinophils was higher in BAL fluid from the asthmatics compared with that in BAL fluid from the control group (p < 0.001). The percentage of the BAL eosinophils significantly correlated with both PC20 of methacholine (r = - 0.58, p = 0.01) and PD20 of distilled cold water (r = -0.81, p = 0.002). No relationship between PC20 of methacholine or PD20 of distilled cold water was found for other inflammatory BAL cells. This study showed that in patients with mustard gas-induced asthma, the degree of airway responsiveness to both methacholine and distilled water was associated with the percentage of BAL eosinophils.

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

    SciTech Connect

    Vitelaru, Catalin; Lundin, Daniel; Brenning, Nils; Minea, Tiberiu

    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.

  1. Biofunctionalized magnetic nanoparticles for high-sensitivity immunomagnetic detection of human C-reactive protein

    NASA Astrophysics Data System (ADS)

    Horng, H. E.; Yang, S. Y.; Hong, Chin-Yih; Liu, C. M.; Tsai, P. S.; Yang, H. C.; Wu, C. C.

    2006-06-01

    In this work, we developed immunomagnetic detection techniques for detecting human C-reactive protein (CRP). To enhance the technique's sensitivity to human CRP, biofunctionalized magnetic nanoparticles were used as markers, and a superconductive quantum interference device gradiometer system was adapted to measure the saturated magnetization of magnetically labeled CRP-anti-CRP immune complexes. Sensitivity for human CRP was found to be as high as 1ng in 0.1ml, i.e., 10ng/ml in concentration. This sensitivity is much higher than that of conventional enzyme linked immunosorbent assay by one order of magnitude.

  2. 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.

  3. 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.

  4. Highly mobile and reactive state of hydrogen in metal oxide semiconductors at room temperature

    PubMed Central

    Chen, Wan Ping; He, Ke Feng; Wang, Yu; Chan, Helen Lai Wah; Yan, Zijie

    2013-01-01

    Hydrogen in metal oxides usually strongly associates with a neighboring oxygen ion through an O-H bond and thus displays a high stability. Here we report a novel state of hydrogen with unusually high mobility and reactivity in metal oxides at room temperature. We show that freshly doped hydrogen in Nb2O5 and WO3 polycrystals via electrochemical hydrogenation can reduce Cu2+ ions into Cu0 if the polycrystals are immersed in a CuSO4 solution, while this would not happen if the hydrogenated polycrystals have been placed in air for several hours before the immersion. Time-dependent studies of electrochemically hydrogenated rutile single crystals reveal two distinct states of hydrogen: one as protons covalently bonded to oxygen ions, while the other one is highly unstable with a lifetime of just a few hours. Observation of this mobile and reactive state of hydrogen will provide new insight into numerous moderate and low temperature interactions between metal oxides and hydrogen. PMID:24193143

  5. High-frequency nanofluidics: a universal formulation of the fluid dynamics of MEMS and NEMS.

    PubMed

    Ekinci, K L; Yakhot, V; Rajauria, S; Colosqui, C; Karabacak, D M

    2010-11-21

    A solid body undergoing oscillatory motion in a fluid generates an oscillating flow. Oscillating flows in Newtonian fluids were first treated by G.G. Stokes in 1851. Since then, this problem has attracted much attention, mostly due to its technological significance. Recent advances in micro- and nanotechnology require that this problem be revisited: miniaturized mechanical resonators with linear dimensions in microns and sub-microns-microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS), respectively-give rise to oscillating flows when operated in fluids. Yet flow parameters for these devices, such as the characteristic flow time and length scales, may deviate greatly from those in Stokes' solution. As a result, new and interesting physics emerges with important consequences to device applications. In this review, we shall provide an introduction to this area of fluid dynamics, called high-frequency nanofluidics, with emphasis on both theory and experiments.

  6. Phase equilibria in fluid mixtures at high pressures: The He-CH4 system

    NASA Technical Reports Server (NTRS)

    Streett, W. B.; Erickson, A. L.; Hill, J. L. E.

    1972-01-01

    An experimental study of phase equilibria in the He-CH4 system was carried out over the temperature range 95 to 290 K and at pressures to 10,000 atm. The experimental results consist of equilibrium phase composition for twenty-eight isotherms in the region of coexistence of two fluid phases, together with the pressure-temperature trace of the three-phase boundary at which a CH4-rich solid phase is in equilibrium with the two fluid phases. The system exhibits a fluid-fluid phase separation which persists to temperatures and pressures beyond the range of this experiment. These results, together with those recently obtained for other binary systems, provide information about the form of phase diagrams for binary gas mixtures in the region of pressure induced phase transitions at high pressures. These findings are relevant to problems of deep atmosphere and interior structures in the outer planets.

  7. Temperature-stable polymeric fluid-loss reducer tolerant to high electrolyte contamination

    SciTech Connect

    Son, A.J.; Ballard, T.M.; Loftin, R.E.

    1984-09-01

    Drilling deep hot wells with water-based fluids has been limited by lack of additives that would maintain stable rheologies and fluid loss properties at elevated temperatures. The problem is accelerated when high chemical contaminants are encountered, such as salts of sodium, calcium, magnesium, etc. The copolymer of styrene and maleic anhydride is stable at temperatures over 400/sup 0/F and it functions as a rheology stabilizer but does not provide fluid loss control. A new synthetic polymer is now available which provides dual function of rheological stabilization and fluid loss control under such unfavorable conditions. The paper discusses the unique functionalities of the new breed of polymers, performance under drastic conditions of temperature and electrolyte contamination and field case histories.

  8. Fluid-Structure Interaction Modeling of High-Aspect Ratio Nuclear Fuel Plates Using COMSOL

    SciTech Connect

    Curtis, Franklin G; Ekici, Kivanc; Freels, James D

    2013-01-01

    The High Flux Isotope Reactor at the Oak Ridge National Lab is in the research stage of converting its fuel from high-enriched uranium to low-enriched uranium. Due to different physical properties of the new fuel and changes to the internal fuel plate design, the current safety basis must be re-evaluated through rigorous computational analyses. One of the areas being explored is the fluid-structure interaction phenomenon due to the interaction of thin fuel plates (50 mils thickness) and the cooling fluid (water). Detailed computational fluid dynamics and fluid-structure interaction simulations have only recently become feasible due to improved numerical algorithms and advancements in computing technology. For many reasons including the already built-in fluid-structure interaction module, COMSOL has been chosen for this complex problem. COMSOL's ability to solve multiphysics problems using a fully-coupled and implicit solution algorithm is crucial in obtaining a stable and accurate solution. Our initial findings show that COMSOL can accurately model such problems due to its ability to closely couple the fluid dynamics and the structural dynamics problems.

  9. Fluid shielding of high-velocity jet noise

    NASA Technical Reports Server (NTRS)

    Goodykoontz, J. H.

    1984-01-01

    Experimental noise data for a nozzle exhaust system incorporating a thermal acoustic shield (TAS) are presented to show the effect of changes in geometric and flow parameters on attenuation of high-velocity jet exhaust noise in the flyover plane. The results are presented for a 10.00-cm-diameter primary conical nozzle with a TAS configuration consisting of a 2.59- or 5.07-cm-wide annular gap. Shield-stream exhaust velocity was varied from 157 to 248 m/sec to investigate the effect of velocity ratio. The results showed that increasing the annular gap width increases attenuation of high-frequency noise when comparisons are made on the same ideal thrust basis. Varying the velocity ratio had a minor effect on the noise characteristics of the nozzles investigated.

  10. Properties of planetary fluids at high pressure and temperature

    NASA Technical Reports Server (NTRS)

    Nellis, W. J.; Hamilton, D. C.; Holmes, N. C.; Radousky, H. B.; Ree, F. H.; Ross, M.; Young, D. A.; Nicol, M.

    1987-01-01

    In order to derive models of the interiors of Uranus, Neptune, Jupiter and Saturn, researchers studied equations of state and electrical conductivities of molecules at high dynamic pressures and temperatures. Results are given for shock temperature measurements of N2 and CH4. Temperature data allowed demonstration of shock induced cooling in the the transition region and the existence of crossing isotherms in P-V space.

  11. Hypersaline fluids generated by high-grade metamorphism of evaporites: fluid inclusion study of uranium occurrences in the Western Zambian Copperbelt

    NASA Astrophysics Data System (ADS)

    Eglinger, Aurélien; Ferraina, Clément; Tarantola, Alexandre; André-Mayer, Anne-Sylvie; Vanderhaeghe, Olivier; Boiron, Marie-Christine; Dubessy, Jean; Richard, Antonin; Brouand, Marc

    2014-02-01

    In the Pan-African Lufilian belt (Western Zambian Copperbelt), uranium mineralizations, preferentially scattered in kyanite ± talc micaschists (metamorphosed evaporitic sediments) or concentrated along transposed quartz veins provide an opportunity to (1) understand the time/space relationship between the ore minerals and the deformation of the host rocks, (2) identify the different fluid events associated with specific stages of quartz deformation and (3) characterize the ore fluid geochemistry in terms of fluid origin and fluid/rock interactions. In the U occurrences studied in Lolwa and Mitukuluku (Domes region, Western Zambian Copperbelt), two mineralizing stages are described. The first generation of ore fluids (53-59 wt% CaCl2, 13-15 wt% NaCl; N2-H2 in the gas phase of fluid inclusions) circulated during the high-temperature quartz recrystallization, at 500-700 °C. This temperature is in agreement with the P- T conditions recorded during the crustal thickening related to continental collision at ca. 530 Ma. LA-ICPMS analyses show the presence of uranium within this fluid, with a concentration mode around 20 ppm. The second generation of ore fluid (21-32 wt% NaCl, 19-21 wt% CaCl2; CO2-CO in the gas phase of fluid inclusions) percolated at lower temperature conditions, at the brittle-ductile transition, between 200 and 300 °C. This temperature could be related to the exhumation of the high-grade metamorphic rocks at ca. 500 Ma. The formation of H2 and CO is interpreted as the result of radiolysis in the presence of dissolved uranium in the aqueous phase of these fluid inclusions. Finally, a late fluid (14-16 wt% NaClequiv) circulated in the brittle domain but seems unrelated to U (re-)mobilization event.

  12. Cerebrospinal fluid high mobility group box 1 is associated with neuronal death in subarachnoid hemorrhage.

    PubMed

    Wang, Kuo-Chuan; Tang, Sung-Chun; Lee, Jing-Er; Li, Yu-I; Huang, Yi-Shuian; Yang, Wei-Shiung; Jeng, Jiann-Shing; Arumugam, Thiruma V; Tu, Yong-Kwang

    2017-02-01

    We aim to determine the cerebrospinal fluid levels of high mobility group box 1 in subarachnoid hemorrhage patients and to investigate the involvement of the receptor for advanced glycation end products and high mobility group box 1 in the pathogenesis of post-subarachnoid hemorrhage neuronal death. The study included 40 patients (mean age, 59 ± 19 years) with Fisher's grade ≥ III aneurysmal subarachnoid hemorrhage. Cerebrospinal fluid was collected on the seventh day post-hemorrhage. Receptor for advanced glycation end products expression was examined in rat brain tissue following subarachnoid hemorrhage and in cultured neurons exposed to post-subarachnoid hemorrhage cerebrospinal fluid. Therapeutic effects of the recombinant soluble form of RAGE on subarachnoid hemorrhage models were also investigated. The results indicated that a higher level of cerebrospinal fluid high mobility group box 1 was independently associated with unfavorable outcome at three months post-subarachnoid hemorrhage (OR = 1.061, 95% CI: 1.005-1.121). Expression of RAGE increased in post-subarachnoid hemorrhage rat brain cells and in cultured neuron with stimulation of post-subarachnoid hemorrhage cerebrospinal fluid. Administration of recombinant soluble form of RAGE significantly reduced the number of positive TUNEL staining cells in subarachnoid hemorrhage rat and improved cell viability in post-subarachnoid hemorrhage cerebrospinal fluid-treated cultured neurons. Thus, the level of cerebrospinal fluid high mobility group box 1 can be a prognostic indicator for patients with Fisher's grade ≥ III aneurysmal subarachnoid hemorrhage and that treatment with soluble form of RAGE is a novel approach for subarachnoid hemorrhage.

  13. Highly deformable and highly fluid vesicles as potential drug delivery systems: theoretical and practical considerations

    PubMed Central

    Romero, Eder Lilia; Morilla, Maria Jose

    2013-01-01

    Vesicles that are specifically designed to overcome the stratum corneum barrier in intact skin provide an efficient transdermal (systemic or local) drug delivery system. They can be classified into two main groups according to the mechanisms underlying their skin interaction. The first group comprises those possessing highly deformable bilayers, achieved by incorporating edge activators to the bilayers or by mixing with certain hydrophilic solutes. The vesicles of this group act as drug carriers that penetrate across hydrophilic pathways of the intact skin. The second group comprises those possessing highly fluid bilayers, owing to the presence of permeation enhancers. The vesicles of this group can act as carriers of drugs that permeate the skin after the barrier of the stratum corneum is altered because of synergistic action with the permeation enhancers contained in the vesicle structure. We have included a detailed overview of the different mechanisms of skin interaction and discussed the most promising preclinical applications of the last five years of Transfersomes® (IDEA AG, Munich, Germany), ethosomes, and invasomes as carriers of antitumoral and anti-inflammatory drugs applied by the topical route. PMID:23986634

  14. Fluid mechanical proximity effects in high-resolution gravure printing for printed electronics

    NASA Astrophysics Data System (ADS)

    Grau, Gerd; Scheideler, William J.; Subramanian, Vivek

    2016-11-01

    Gravure printing is a very promising method for printed electronics because it combines high throughput with high resolution. Recently, printed lines with 2 micrometer resolution have been demonstrated at printing speeds on the order of 1m/s. In order to build realistic circuits, the fluid dynamics of complex pattern formation needs to be studied. Recently, we showed that highly-scaled lines printed in close succession exhibit proximity effects that can either improve or deteriorate print quality depending on a number of parameters. It was found that this effect occurs if cells are connected by a thin fluid film. Here, we present further experimental and modeling results explaining the mechanism by which this thin fluid film affects pattern formation. During the transfer of ink from the roll to the substrate, ink can flow in between connected cells. Asymmetry in the fluid distribution created by the preceding doctor blade wiping process results in net fluid flow from cells that transfer first to cells that transfer subsequently. The proximity of these cells thus affects the final ink distribution on the substrate, which is critically important to understand and design optimally when printing highly-scaled patterns of electronic materials. This work is based upon work supported in part by the National Science Foundation under Cooperative Agreement No. EEC-1160494.

  15. 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.

  16. High on-treatment platelet reactivity in transcatheter aortic valve implantation patients.

    PubMed

    Polzin, Amin; Schleicher, Mathias; Seidel, Holger; Scharf, Rüdiger E; Merx, Marc W; Kelm, Malte; Zeus, Tobias

    2015-03-15

    Dual antiplatelet therapy (DAPT) is recommended early after transcatheter aortic valve implantation (TAVI) procedure at the moment despite the lack of evidence. Two small randomized trials failed to demonstrate DAPT to be superior to aspirin alone in TAVI patients. However, it is known that there are substantial response variabilities to antiplatelet medication. We aimed to investigate high on-treatment platelet reactivity (HTPR), low on-treatment platelet reactivity (LTPR) to clopidogrel as well as HTPR to aspirin in patients undergoing TAVI procedure. We analyzed data of 140 TAVI patients in a real world observational study. Platelet function assays (clopidogrel-vasodilator-stimulated protein phosphorylation assay; aspirin-light-transmission aggregometry) have been performed during hospital course. Clinical complications were investigated during 30 days follow-up and defined using the valve academic research consortium standardized criteria. HTPR to clopidogrel occurred in 87 (62%) patients and LTPR in 9 (6.4%) patients. Aspirin antiplatelet effects were insufficient in 25 (18%) patients. Clinical complications were observed in 35 (25%) patients. Ischemic events occurred in 6 (4%), bleeding complications in 28 (20%) patients. There were no differences regarding the incidence of HTPR/LTPR in patients with overall complications, ischemic events or bleeding events. HTPR to clopidogrel is very frequent in TAVI patients. However bleeding complications are frequent and ischemic events are rare. Therefore, future clinical trials investigating the optimal antithrombotic regiment in TAVI patients should consider this high incidence of HTPR to clopidogrel and monitor clopidogrel antiplatelet effects carefully.

  17. Brain reactivity differentiates subjects with high and low dream recall frequencies during both sleep and wakefulness.

    PubMed

    Eichenlaub, Jean-Baptiste; Bertrand, Olivier; Morlet, Dominique; Ruby, Perrine

    2014-05-01

    The neurophysiological correlates of dreaming remain unclear. According to the "arousal-retrieval" model, dream encoding depends on intrasleep wakefulness. Consistent with this model, subjects with high and low dream recall frequency (DRF) report differences in intrasleep awakenings. This suggests a possible neurophysiological trait difference between the 2 groups. To test this hypothesis, we compared the brain reactivity (evoked potentials) of subjects with high (HR, N = 18) and low (LR, N = 18) DRF during wakefulness and sleep. During data acquisition, the subjects were presented with sounds to be ignored (first names randomly presented among pure tones) while they were watching a silent movie or sleeping. Brain responses to first names dramatically differed between the 2 groups during both sleep and wakefulness. During wakefulness, the attention-orienting brain response (P3a) and a late parietal response were larger in HR than in LR. During sleep, we also observed between-group differences at the latency of the P3a during N2 and at later latencies during all sleep stages. Our results demonstrate differences in the brain reactivity of HR and LR during both sleep and wakefulness. These results suggest that the ability to recall dreaming is associated with a particular cerebral functional organization, regardless of the state of vigilance.

  18. Modeling high gradient magnetic separation from biological fluids.

    SciTech Connect

    Bockenfeld, D.; Chen, H.; Rempfer, D.; Kaminski, M. D.; Rosengart, A. J.; Chemical Engineering; Illinois Inst. of Tech.; Univ. of Chicago, Pritzker School of Medicine

    2006-01-01

    A proposed portable magnetic separator consists of an array of biocompatible capillary tubing and magnetizable wires immersed in an externally applied homogeneous magnetic field. While subject to the homogeneous magnetic field, the wires create high magnetic field gradients, which aid in the collection of blood-borne magnetic nanospheres from blood flow. In this study, a 3-D numerical model was created using COMSOL Multiphysics 3.2 software to determine the configuration of the wire-tubing array from two possible configurations, one being an array with rows alternating between wires and tubing, and the other being an array where wire and tubing alternate in two directions. The results demonstrated that the second configuration would actually capture more of the magnetic spheres. Experimental data obtained by our group support this numerical result.

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

    SciTech Connect

    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 positions 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.

  20. Success grows in pumping high-gas-fraction multiphase fluids

    SciTech Connect

    Butler, B.

    1999-07-01

    Judging from the reports from user companies and discussions at the pump symposium following the 1999 Offshore Technology Conference, three kinds of pumps have now progressed to the point where they might be considered commercial and have demonstrated their ability to handle a variety of multiphase flows. These are twin screw, progressive cavity, and helico-axial (H-A) pumps. The twin-screw and progressive cavity (PC) pumps are positive displacement. They develop pressure hydrostatically and are less sensitive to density changes. The H-A type is a centrifugal pump which develops pressure dynamically and is highly sensitive to variation in density which is a characteristic of a multiphase flow stream. Now that the technical hurdles are better understood, it is time to look at economic viability. The close links between inlet pressure, gas volumes, and cost can be demonstrated and general cost relationships can be suggested. This discussion focuses on surface applications using twin-screw pumps that have the most applications and data highlighting actual field experience of major oil and gas companies who benefit from this type of multiphase technology.

  1. Fluid Modeling of a Very High Frequency Capacitively Coupled Reactor

    NASA Astrophysics Data System (ADS)

    Upadhyay, Rochan; Raja, Laxminarayan; Ventzek, Peter; Iwao, Toshihiko; Ishibashi, Kiyotaka; Esgee Technologies Inc. Collaboration; University of Texas at Austin Collaboration; Tokyo Electron Ltd. Collaboration

    2016-09-01

    Very High Frequency Capacitively Coupled Plasma (VHF-CCP) discharges have been studied extensively for semiconductor manufacturing applications for well over a decade. Modeling of these discharges however poses significant challenges owing to complexity associated with simulation of multiple coupled phenomena (electro-static/magnetic fields and plasma physics) over different scales and the representation of these phenomena in a computational framework. We present 2D simulations of a self-consistent plasma with the electromagnetic field represented using vector and scalar potentials. For a range of operating conditions, the ratio of capacitive and inductive power, calculated using empirical correlations available in the literature, are matched by adjusting both the electrostatic and electromagnetic fields in a decoupled manner. We present results using this model that demonstrate most of the important VHF-CCP discharge phenomena reported in the literature, such as electromagnetic wave versus electrostatic heating and its impact on plasma non-uniformity, wave resonances, etc. while realizing a practically feasible computational model.

  2. 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).

  3. Usefulness of high-resolution thermography in fault diagnosis of fluid power components and systems

    NASA Astrophysics Data System (ADS)

    Pietola, Matti; Varrio, Jukka P.

    1996-03-01

    Infrared thermography has been used routinely in industrial applications for quite a long time. For example, the condition of electric power lines, district heating networks, electric circuits and components, heat exchangers, pipes and its insulations, cooling towers, and various machines and motors is monitored using infrared imaging techniques. Also the usage of this technology in predictive maintenance has proved successful, mainly because of effective computers and tailored softwares available. However, the usage of thermal sensing technique in fluid power systems and components (or other automation systems in fact) is not as common. One apparent reason is that a fluid power circuit is not (and nor is a hydraulic component) an easy object of making thermal image analyses. Especially the high flow speed, fast pressure changes and fast movements make the diagnosis complex and difficult. Also the number of people whose knowledge is good both in thermography and fluid power systems is not significant. In this paper a preliminary study of how thermography could be used in the condition monitoring, fault diagnosis and predictive maintenance of fluid power components and systems is presented. The shortages and limitations of thermal imaging in the condition monitoring of fluid power are also discussed. Among many other cases the following is discussed: (1) pressure valves (leakage, wrong settings), (2) check valves (leakage); (3) cylinders (leakage and other damages); (4) directional valves and valve assemblies; (5) pumps and motors (leakage in piston or control plate, bearings). The biggest advantage of using thermography in the predictive maintenance and fault diagnosis of fluid power components and systems could be achieved in the process industry and perhaps in the commissioning of fluid power systems in the industry. In the industry the predictive maintenance of fluid power with the aid of an infrared camera could be done as part of a condition monitoring of

  4. High-resolution proton nuclear magnetic resonance spectroscopy of ovarian cyst fluid.

    PubMed

    Boss, E A; Moolenaar, S H; Massuger, L F; Boonstra, H; Engelke, U F; de Jong, J G; Wevers, R A

    2000-08-01

    Most ovarian tumors are cystic structures containing variable amounts of fluid. Several studies of ovarian cyst fluid focus on one specific metabolite using conventional assay systems. We examined the potential of (1)H-nuclear magnetic resonance spectroscopy in evaluation of the overall metabolic composition of cyst fluid from different ovarian tumors. Ovarian cyst fluid samples obtained from 40 patients with a primary ovarian tumor (12 malignant and 28 benign) were examined. After deproteinization and pD standardization, we performed (1)H-NMR spectroscopy on a 600 MHz instrument. With (1)H-NMR spectroscopy we found detectable concentrations of 36 metabolites with high intersample variation. A number of unassigned resonances as well as unexpected metabolites were found. We introduce an overall inventory of the low-molecular-weight metabolites in ovarian cyst fluid with corresponding resonances. Significant differences in concentration (p < 0.01) were found for several metabolites (including an unknown metabolite) between malignant and benign ovarian cysts. Furthermore, higher concentrations in malignant- and lower in benign fluids were found compared to normal serum values, indicating local cyst wall metabolic processes in case of malignant transformation. We conclude that (1)H-nuclear magnetic resonance spectroscopy can give an overview of low-molecular-weight proton-containing metabolities present in ovarian cyst fluid samples. The metabolic composition of cyst fluid differs significantly between benign and malignant ovarian tumors. Furthermore, differences between benign subgroups possibly related to histopathological behaviour can be detected. The presence of N-acetyl aspartic acid and 5-oxoproline exclusively in serous cystadenoma samples is remarkable. Future studies will concentrate on these findings and explore the possibilities of extrapolating information from the in vitro studies to in vivo practice, in which metabolic differences between malignant and

  5. 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.

  6. Ice sheets as a significant source of highly reactive nanoparticulate iron to the oceans.

    PubMed

    Hawkings, Jon R; Wadham, Jemma L; Tranter, Martyn; Raiswell, Rob; Benning, Liane G; Statham, Peter J; Tedstone, Andrew; Nienow, Peter; Lee, Katherine; Telling, Jon

    2014-05-21

    The Greenland and Antarctic Ice Sheets cover ~ 10% of global land surface, but are rarely considered as active components of the global iron cycle. The ocean waters around both ice sheets harbour highly productive coastal ecosystems, many of which are iron limited. Measurements of iron concentrations in subglacial runoff from a large Greenland Ice Sheet catchment reveal the potential for globally significant export of labile iron fractions to the near-coastal euphotic zone. We estimate that the flux of bioavailable iron associated with glacial runoff is 0.40-2.54 Tg per year in Greenland and 0.06-0.17 Tg per year in Antarctica. Iron fluxes are dominated by a highly reactive and potentially bioavailable nanoparticulate suspended sediment fraction, similar to that identified in Antarctic icebergs. Estimates of labile iron fluxes in meltwater are comparable with aeolian dust fluxes to the oceans surrounding Greenland and Antarctica, and are similarly expected to increase in a warming climate with enhanced melting.

  7. Current-voltage-time characteristics of the reactive Ar/N{sub 2} high power impulse magnetron sputtering discharge

    SciTech Connect

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

    2011-10-15

    The discharge current and voltage waveforms have been measured in a reactive high power impulse magnetron sputtering (HiPIMS) Ar/N{sub 2} discharge with a Ti target for 400 {mu}s long pulses. We observe that the current waveform in the reactive Ar/N{sub 2} HiPIMS discharge is highly dependent on the pulse repetition frequency, unlike the non-reactive Ar discharge. The current is found to increase significantly as the frequency is lowered. This is attributed to an increase in the secondary electron emission yield during the self-sputtering phase, when the nitride forms on the target at low frequencies. In addition, self-sputtering runaway occurs at lower discharge voltages when nitrogen is added to the discharge. This illustrates the crucial role of self-sputtering in the behavior of the reactive HiPIMS discharge.

  8. Trapping a Highly Reactive Nonheme Iron Intermediate That Oxygenates Strong C-H Bonds with Stereoretention.

    PubMed

    Serrano-Plana, Joan; Oloo, Williamson N; Acosta-Rueda, Laura; Meier, Katlyn K; Verdejo, Begoña; García-España, Enrique; Basallote, Manuel G; Münck, Eckard; Que, Lawrence; Company, Anna; Costas, Miquel

    2015-12-23

    An unprecedentedly reactive iron species (2) has been generated by reaction of excess peracetic acid with a mononuclear iron complex [Fe(II)(CF3SO3)2(PyNMe3)] (1) at cryogenic temperatures, and characterized spectroscopically. Compound 2 is kinetically competent for breaking strong C-H bonds of alkanes (BDE ≈ 100 kcal·mol(-1)) through a hydrogen-atom transfer mechanism, and the transformations proceed with stereoretention and regioselectively, responding to bond strength, as well as to steric and polar effects. Bimolecular reaction rates are at least an order of magnitude faster than those of the most reactive synthetic high-valent nonheme oxoiron species described to date. EPR studies in tandem with kinetic analysis show that the 490 nm chromophore of 2 is associated with two S = 1/2 species in rapid equilibrium. The minor component 2a (∼5% iron) has g-values at 2.20, 2.19, and 1.99 characteristic of a low-spin iron(III) center, and it is assigned as [Fe(III)(OOAc)(PyNMe3)](2+), also by comparison with the EPR parameters of the structurally characterized hydroxamate analogue [Fe(III)(tBuCON(H)O)(PyNMe3)](2+) (4). The major component 2b (∼40% iron, g-values = 2.07, 2.01, 1.95) has unusual EPR parameters, and it is proposed to be [Fe(V)(O)(OAc)(PyNMe3)](2+), where the O-O bond in 2a has been broken. Consistent with this assignment, 2b undergoes exchange of its acetate ligand with CD3CO2D and very rapidly reacts with olefins to produce the corresponding cis-1,2-hydroxoacetate product. Therefore, this work constitutes the first example where a synthetic nonheme iron species responsible for stereospecific and site selective C-H hydroxylation is spectroscopically trapped, and its catalytic reactivity against C-H bonds can be directly interrogated by kinetic methods. The accumulated evidence indicates that 2 consists mainly of an extraordinarily reactive [Fe(V)(O)(OAc)(PyNMe3)](2+) (2b) species capable of hydroxylating unactivated alkyl C-H bonds with

  9. Hysteresis-free high rate reactive sputtering of niobium oxide, tantalum oxide, and aluminum oxide

    SciTech Connect

    Särhammar, Erik Berg, Sören; Nyberg, Tomas

    2014-07-01

    This work reports on experimental studies of reactive sputtering from targets consisting of a metal and its oxide. The composition of the targets varied from pure metal to pure oxide of Al, Ta, and Nb. This combines features from both the metal target and oxide target in reactive sputtering. If a certain relation between the metal and oxide parts is chosen, it may be possible to obtain a high deposition rate, due to the metal part, and a hysteresis-free process, due to the oxide part. The aim of this work is to quantify the achievable boost in oxide deposition rate from a hysteresis-free process by using a target consisting of segments of a metal and its oxide. Such an increase has been previously demonstrated for Ti using a homogeneous substoichiometric target. The achievable gain in deposition rate depends on transformation mechanisms from oxide to suboxides due to preferential sputtering of oxygen. Such mechanisms are different for different materials and the achievable gain is therefore material dependent. For the investigated materials, the authors have demonstrated oxide deposition rates that are 1.5–10 times higher than what is possible from metal targets in compound mode. However, although the principle is demonstrated for oxides of Al, Ta, and Nb, a similar behavior is expected for most oxides.

  10. Highly sensitive SnO2 sensor via reactive laser-induced transfer.

    PubMed

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

    2016-04-27

    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.

  11. 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

  12. Highly sensitive SnO2 sensor via reactive laser-induced transfer

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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.

  13. Highly parameterized inversion of groundwater reactive transport for a complex field site

    NASA Astrophysics Data System (ADS)

    Carniato, Luca; Schoups, Gerrit; van de Giesen, Nick; Seuntjens, Piet; Bastiaens, Leen; Sapion, Hans

    2015-02-01

    In this study a numerical groundwater reactive transport model of a shallow groundwater aquifer contaminated with volatile organic compounds is developed. In addition to advective-dispersive transport, the model includes contaminant release from source areas, natural attenuation, abiotic degradation by a permeable reactive barrier at the site, and dilution by infiltrating rain. Aquifer heterogeneity is parameterized using pilot points for hydraulic conductivity, specific yield and groundwater recharge. A methodology is developed and applied to estimate the large number of parameters from the limited data at the field site (groundwater levels, groundwater concentrations of multiple chemical species, point-scale measurements of soil hydraulic conductivity, and lab-scale derived information on chemical and biochemical reactions). The proposed methodology relies on pilot point parameterization of hydraulic parameters and groundwater recharge, a regularization procedure to reconcile the large number of spatially distributed model parameters with the limited field data, a step-wise approach for integrating the different data sets into the model, and high performance computing. The methodology was proven to be effective in reproducing multiple contaminant plumes and in reducing the prior parameter uncertainty of hydraulic conductivity and groundwater recharge. Our results further indicate that contaminant transport predictions are strongly affected by the choice of the groundwater recharge model and flow parameters should be identified using both head and concentration measurements.

  14. Highly parameterized inversion of groundwater reactive transport for a complex field site.

    PubMed

    Carniato, Luca; Schoups, Gerrit; van de Giesen, Nick; Seuntjens, Piet; Bastiaens, Leen; Sapion, Hans

    2015-02-01

    In this study a numerical groundwater reactive transport model of a shallow groundwater aquifer contaminated with volatile organic compounds is developed. In addition to advective-dispersive transport, the model includes contaminant release from source areas, natural attenuation, abiotic degradation by a permeable reactive barrier at the site, and dilution by infiltrating rain. Aquifer heterogeneity is parameterized using pilot points for hydraulic conductivity, specific yield and groundwater recharge. A methodology is developed and applied to estimate the large number of parameters from the limited data at the field site (groundwater levels, groundwater concentrations of multiple chemical species, point-scale measurements of soil hydraulic conductivity, and lab-scale derived information on chemical and biochemical reactions). The proposed methodology relies on pilot point parameterization of hydraulic parameters and groundwater recharge, a regularization procedure to reconcile the large number of spatially distributed model parameters with the limited field data, a step-wise approach for integrating the different data sets into the model, and high performance computing. The methodology was proven to be effective in reproducing multiple contaminant plumes and in reducing the prior parameter uncertainty of hydraulic conductivity and groundwater recharge. Our results further indicate that contaminant transport predictions are strongly affected by the choice of the groundwater recharge model and flow parameters should be identified using both head and concentration measurements.

  15. Properties of molecular solids and fluids at high pressure and temperatures

    SciTech Connect

    Etters, R.D.

    1992-03-01

    This renewal request for DOE grant DE-FG02-86ER45238, is dedicated to providing a complete thermodynamic profile of solids fluids, and fluid mixtures, over a wide range of temperatures and pressures. We are partially motivated by technological interest in detonation, combustion, superhard high pressure materials, and high temperature superconductors, which are important components of interest of various DOE laboratories. Our work on fluids and solids, composed of simple molecules, involves the determination of structures, phase transitions, pressure-volume relations, phonon, vibron, and libron modes of excitation, sound velocities, specific heats, thermal expansion, virial coefficients, sublimation energies, and orientational translational, and magnetic correlations. We hope that the study of these systems under extreme thermodynamic conditions will lead to exotic new materials of value, as well as enhanced fundamental understanding.

  16. Advances in comparative physiology from high-speed imaging of animal and fluid motion.

    PubMed

    Lauder, George V; Madden, Peter G A

    2008-01-01

    Since the time of Muybridge and Marey in the last half of the nineteenth century, studies of animal movement have relied on some form of high-speed or stop-action imaging to permit analysis of appendage and body motion. In the past ten years, the advent of megapixel-resolution high-speed digital imaging with maximal framing rates of 250 to 100,000 images per second has allowed new views of musculoskeletal function in comparative physiology that now extend to imaging flow around moving animals and the calculation of fluid forces produced by animals moving in fluids. In particular, the technique of digital particle image velocimetry (DPIV) has revolutionized our ability to understand how moving animals generate fluid forces and propel themselves through air and water. DPIV algorithms generate a matrix of velocity vectors through the use of image cross-correlation, which can then be used to calculate the force exerted on the fluid as well as locomotor work and power. DPIV algorithms can also be applied to images of moving animals to calculate the velocity of different regions of the moving animal, providing a much more detailed picture of animal motion than can traditional digitizing methods. Although three-dimensional measurement of animal motion is now routine, in the near future model-based kinematic reconstructions and volumetric analyses of animal-generated fluid flow patterns will provide the next step in imaging animal biomechanics and physiology.

  17. Modulation of reactive oxygen species by salicylic acid in Arabidopsis seed germination under high salinity.

    PubMed

    Lee, Sangmin; Park, Chung-Mo

    2010-12-01

    Potential roles of salicylic acid (SA) on seed germination have been explored in many plant species. However, it is still controversial how SA regulates seed germination, mainly because the results have been somewhat variable, depending on plant genotypes used and experimental conditions employed. We found that SA promotes seed germination under high salinity in Arabidopsis. Seed germination of the sid2 mutant, which has a defect in SA biosynthesis, is hypersensitive to high salinity, but the inhibitory effects are reduced in the presence of physiological concentrations of SA. Abiotic stresses, including high salinity, impose oxidative stress on plants. Endogenous contents of H(2)O(2) are higher in the sid2 mutant seeds. However, exogenous application of SA reduces endogenous level of reactive oxygen species (ROS), indicating that SA is involved in plant responses to ROS-mediated damage under abiotic stress conditions. Gibberellic acid (GA), a plant hormone closely associated with seed germination, also reverses the inhibitory effects of high salinity on seed germination and seedling establishment. Under high salinity, GA stimulates SA biosynthesis by inducing the SID2 gene. Notably, SA also induces genes encoding GA biosynthetic enzymes. These observations indicate that SA promotes seed germination under high salinity by modulating antioxidant activity through signaling crosstalks with GA.

  18. High Platelet Reactivity in Patients with Acute Coronary Syndromes Undergoing Percutaneous Coronary Intervention: Randomised Controlled Trial Comparing Prasugrel and Clopidogrel

    PubMed Central

    Geisler, Tobias; Booth, Jean; Tavlaki, Elli; Karathanos, Athanasios; Müller, Karin; Droppa, Michal; Gawaz, Meinrad; Yanez-Lopez, Monica; Davidson, Simon J.; Stables, Rod H.; Banya, Winston; Zaman, Azfar; Flather, Marcus; Dalby, Miles

    2015-01-01

    Background Prasugrel is more effective than clopidogrel in reducing platelet aggregation in acute coronary syndromes. Data available on prasugrel reloading in clopidogrel treated patients with high residual platelet reactivity (HRPR) i.e. poor responders, is limited. Objectives To determine the effects of prasugrel loading on platelet function in patients on clopidogrel and high platelet reactivity undergoing percutaneous coronary intervention for acute coronary syndrome (ACS). Patients Patients with ACS on clopidogrel who were scheduled for PCI found to have a platelet reactivity ≥40 AUC with the Multiplate Analyzer, i.e. “poor responders” were randomised to prasugrel (60 mg loading and 10 mg maintenance dose) or clopidogrel (600 mg reloading and 150 mg maintenance dose). The primary outcome measure was proportion of patients with platelet reactivity <40 AUC 4 hours after loading with study medication, and also at one hour (secondary outcome). 44 patients were enrolled and the study was terminated early as clopidogrel use decreased sharply due to introduction of newer P2Y12 inhibitors. Results At 4 hours after study medication 100% of patients treated with prasugrel compared to 91% of those treated with clopidogrel had platelet reactivity <40 AUC (p = 0.49), while at 1 hour the proportions were 95% and 64% respectively (p = 0.02). Mean platelet reactivity at 4 and 1 hours after study medication in prasugrel and clopidogrel groups respectively were 12 versus 22 (p = 0.005) and 19 versus 34 (p = 0.01) respectively. Conclusions Routine platelet function testing identifies patients with high residual platelet reactivity (“poor responders”) on clopidogrel. A strategy of prasugrel rather than clopidogrel reloading results in earlier and more sustained suppression of platelet reactivity. Future trials need to identify if this translates into clinical benefit. Trial Registration ClinicalTrials.gov NCT01339026 PMID:26317618

  19. Fluid flow along North American Cordillera detachments determined from stable isotope and high resolution chemical analyses

    NASA Astrophysics Data System (ADS)

    Quilichini, A.; Teyssier, C.; Mulch, A.; Nachlas, W.

    2009-12-01

    Fluid flow is likely a major parameter controlling the dynamics of extensional detachment zones. Buoyancy-driven fluid flow is generated by high heat flow beneath the detachment zone, where heat is advected by crustal thinning and magma intrusions. This hydrothermal convective flow is focused in the detachment zone for the duration of activity of the detachment at relatively high temperature (300-500°C), resulting in very significant fluid-rock interaction and isotopic exchange. Quantifying sources and fluid flux in detachments is a challenge because permeability of ductilely deforming rocks is poorly understood. In order to solve these problems, we studied two different Eocene extensional systems in the North American Cordillera: the quartzitic detachment which borders the Kettle dome metamorphic core complex (WA), and the quartzo-feldspathic Bitterroot shear zone along the Idaho batholith (MT). The Kettle Dome detachment provides a continuous section of ~200 m thick quartzite mylonite where high-resolution sampling (~5 m) indicates that Deuterium isotopic ratios that are obtained from synkinematic muscovite grains are consistent with a meteoric fluid source (-130 per mil). In the Bitterroot shear zone, Coyner (2003) reported similar Deuterium isotopic ratios (down to -140 per mil) in muscovite from mylonites and ultramylonites. Microprobe analyses were obtained for white mica porphyroclasts by performing transects perpendicular to the basal (001) cleavage in order to determine intragrain chemical zoning. Preliminary results for the Kettle dome indicate increasing phengite composition with depth, suggesting enhanced activity of the Tschermak exchange. The variations of the phengitic signature in muscovite indicates that temperature diminuish downsection, which is contradictory with the results obtained by the Qz-Ms oxygen isotope thermometer along the Kettle section. Our recent work provides geologic data for numerical models that address the permeability of

  20. High glucose inhibits HCO3(-) and fluid secretion in rat pancreatic ducts.

    PubMed

    Futakuchi, Sachiko; Ishiguro, Hiroshi; Naruse, Satoru; Ko, Shigeru B H; Fujiki, Kotoyo; Yamamoto, Akiko; Nakakuki, Miyuki; Song, Ying; Steward, Martin C; Kondo, Takaharu; Goto, Hidemi

    2009-11-01

    Cellular mechanisms underlying the impairment of pancreatic fluid and electrolyte secretion in diabetes were examined using interlobular ducts isolated from rat pancreas. Fluid secretion was assessed by monitoring changes in luminal volume. HCO3(-) uptake across the basolateral membrane was estimated from the recovery of intracellular pH following an acid load. Exposure to high glucose concentrations inhibited fluid secretion and reduced the rate of basolateral HCO3(-) uptake in secretin-stimulated ducts isolated from normal rats. In ducts isolated from streptozotocin-treated diabetic rats, fluid secretion and basolateral HCO3(-) uptake were also severely impaired but could be largely reversed by incubation in normal-glucose solutions. Sodium-dependent glucose cotransporter 1 (SGLT1), glucose transporter (GLUT)1, GLUT2, and GLUT8 transcripts were detected by reverse transcriptase polymerase chain reaction in isolated ducts. Raising the luminal glucose concentration in microperfused ducts caused a depolarization of the membrane potential, consistent with the presence of SGLT1 at the apical membrane. Unstimulated ducts filled with high-glucose solutions lost luminal fluid by a phlorizin-sensitive mechanism, indicating that pancreatic ducts are capable of active glucose reabsorption from the lumen via SGLT1. In ducts exposed to high glucose concentrations, continuous glucose diffusion to the lumen and active reabsorption via SGLT1 would lead to elevation of intracellular Na+ concentration and sustained depolarization of the apical membrane. These two factors would tend to inhibit the basolateral uptake and apical efflux of Cl(-) and HCO3(-) and could therefore account for the impaired fluid and electrolyte secretion that is observed in diabetes.

  1. Effect of gravity level fluctuations for rotating fluids in high and low rotating speeds

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Tsao, Y. D.; Hong, B. B.; Leslie, F. W.

    1989-01-01

    Time-dependent evolutions of the profile of the free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations of the dynamics of bubble shapes have been carried out with sinusoidal-function vibration of the gravity environment at high and low cylinder speeds.

  2. Magnetorheological fluid behavior in high-frequency oscillatory squeeze mode: Experimental tests and modelling

    NASA Astrophysics Data System (ADS)

    Chen, Peng; Bai, Xian-Xu; Qian, Li-Jun

    2016-03-01

    This paper presents an experimental investigation on the behavior of magnetorheological (MR) fluids in high-frequency oscillatory squeeze mode and proposes a mathematical model to reveal the MR mechanism. A specific MR squeeze structure avoiding the cavitation effect is designed for the experimental tests. The magnetic field- and gap distance-dependent damping force of the MR squeeze structure is presented and compared with the dramatically large damping force under quasi-static excitations, a moderate damping force is observed at high frequencies. Subsequently, in order to interpret the behavior of MR fluids at high frequencies, employing the continuum media theory, a mathematical model is established with consideration of the fluid inertia and hysteresis property. The damping force comparison between the model and experimental tests indicates that in high-frequency oscillatory squeeze mode, the squeeze-strengthen effect does not work and the shear yield stress can be applied well to characterize the flow property of MR fluids. In addition, the hysteresis property has a significant influence on the damping performance.

  3. 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.

  4. 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.

  5. Oxygen Pathway Modeling Estimates High Reactive Oxygen Species Production above the Highest Permanent Human Habitation

    PubMed Central

    Cano, Isaac; Selivanov, Vitaly; Gomez-Cabrero, David; Tegnér, Jesper; Roca, Josep; Wagner, Peter D.; Cascante, Marta

    2014-01-01

    The production of reactive oxygen species (ROS) from the inner mitochondrial membrane is one of many fundamental processes governing the balance between health and disease. It is well known that ROS are necessary signaling molecules in gene expression, yet when expressed at high levels, ROS may cause oxidative stress and cell damage. Both hypoxia and hyperoxia may alter ROS production by changing mitochondrial Po2 (). Because depends on the balance between O2 transport and utilization, we formulated an integrative mathematical model of O2 transport and utilization in skeletal muscle to predict conditions to cause abnormally high ROS generation. Simulations using data from healthy subjects during maximal exercise at sea level reveal little mitochondrial ROS production. However, altitude triggers high mitochondrial ROS production in muscle regions with high metabolic capacity but limited O2 delivery. This altitude roughly coincides with the highest location of permanent human habitation. Above 25,000 ft., more than 90% of exercising muscle is predicted to produce abnormally high levels of ROS, corresponding to the “death zone” in mountaineering. PMID:25375931

  6. High performance low-cost polarizer using depolarization of a polarized light by reactive mesogen.

    PubMed

    Kim, Bong Choon; Lim, Young Jin; Ha, Kyung Su; Lee, Seung Hee; Kang, Wan-Seok; Lee, Gi-Dong

    2011-08-15

    Currently, the polyethlene terephthalate (PET) film challenges to substitute Tri-acetyl cellulouse (TAC) film which is a protection film in a polarizer layer, because of low cost of PET film. On the contrary, the PET film shows an optical problem such that color shift or interference optical pattern in oblique direction can occur because the film is made with the lamination process, which induces high phase retardation. In this paper, we propose a color shift free low cost polarizer by polymerization of random oriented reactive mesogen (RM) on the PET film. We calculate the viewing angle performance of the polarizer with the conventional PET film, with the TAC film and with the proposed PET film. As a result, we confirm that the proposed optical configuration can satisfy the optical performance equivalent to that of conventional TAC film uses in addition to the cost-down.

  7. High osmotic pressure increases reactive oxygen species generation in rabbit corneal epithelial cells by endoplasmic reticulum

    PubMed Central

    Wang, Peng; Sheng, Minjie; Li, Bing; Jiang, Yaping; Chen, Yihui

    2016-01-01

    Tear high osmotic pressure (HOP) has been recognized as the core mechanism underlying ocular surface inflammation, injury and symptoms and is closely associated with many ocular surface diseases, especially dry eye. The endoplasmic reticulum (ER) is a multi-functional organelle responsible for protein synthesis, folding and transport, biological synthesis of lipids, vesicle transport and intracellular calcium storage. Accumulation of unfolded proteins and imbalance of calcium ion in the ER would induce ER stress and protective unfolded protein response (UPR). Many studies have demonstrated that ER stress can induce cell apoptosis. However, the association between tear HOP and ER stress has not been studied systematically. In the present study, rabbit corneal epithelial cells were treated with HOP and results showed that the production of reactive oxygen species increased markedly, which further activated the ER signaling pathway and ultimately induced cell apoptosis. These findings shed new lights on the pathogenesis and clinical treatment of dry eye and other ocular surface diseases. PMID:27158374

  8. Highly sensitive C-reactive protein (CRP) assay using metal-enhanced fluorescence (MEF)

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Keegan, Gemma L.; Stranik, Ondrej; Brennan-Fournet, Margaret E.; McDonagh, Colette

    2015-07-01

    Fluorescence has been extensively employed in the area of diagnostic immunoassays. A significant enhancement of fluorescence can be achieved when noble metal nanoparticles are placed in close proximity to fluorophores. This effect, referred to as metal-enhanced fluorescence (MEF), has the potential to produce immunoassays with a high sensitivity and a low limit of detection (LOD). In this study, we investigate the fluorescence enhancement effect of two different nanoparticle systems, large spherical silver nanoparticles (AgNPs) and gold edge-coated triangular silver nanoplates, and both systems were evaluated for MEF. The extinction properties and electric field enhancement of both systems were modeled, and the optimum system, spherical AgNPs, was used in a sandwich immunoassay for human C-reactive protein with a red fluorescent dye label. A significant enhancement in the fluorescence was observed, which corresponded to an LOD improvement of 19-fold compared to a control assay without AgNPs.

  9. High-temperature thermal degradation of polyethylene from reactive molecular dynamics

    NASA Astrophysics Data System (ADS)

    Lane, J. Matthew D.; Moore, Nathan W.

    Thermal degradation of polyethylene is studied under extremely high-rate temperature ramp rates from 1014 to 1010 K/s in isochoric, condensed phases. The molecular evolution and macroscopic state variables are extracted as a function of density from reactive molecular dynamics simulations using the ReaxFF potential. These results are used to parameterize a kinetic rate model for the dissociation and coalescence of hydrocarbons as a function of temperature, temperature ramp rate, and density. The results are contrasted to first-order random-scission macrokinetic models often assumed for pyrolysis of linear polyethylene under ambient conditions. Sandia National Laboratories is a multi program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04- 94AL85000.

  10. Clinical and angiographic correlation of high-sensitivity C-reactive protein with acute ST elevation myocardial infarction

    PubMed Central

    Tanveer, Syed; Banu, Shaheena; Jabir, Nasimudeen Rehumathbeevi; Khan, Mohd Shahnawaz; Ashraf, Ghulam Md; Manjunath, Nanjappa Cholenahally; Tabrez, Shams

    2016-01-01

    Vascular inflammation and associated ongoing inflammatory responses are considered as the critical culprits in the pathogenesis of acute atherothrombotic events such as acute coronary syndrome (ACS) and myocardial infarction (MI). ST segment elevation myocardial infarction (STEMI) is considered as one of the prominent clinical forms of ACS. Moreover, C-reactive protein (CRP) is an important acute phase prsotein, which may be estimated using high-sensitivity methods (hs-CRP), and its elevated level in body fluids reflects chronic inflammatory status. The circulating hs-CRP level has been proposed as a promising inflammatory marker of coronary artery disease (CAD). The present study investigated the correlation of hs-CRP level with clinical and angiographic features of STEMI, various other traditional risk factors, complications of myocardial infarction and angiographically significant CAD. Out of 190 patients with STEMI that were analyzed, the interval between symptom onset and reperfusion therapy (window period) varied from 0.5 to 24 h. The hs-CRP value was found to be higher in non-diabetic patients (0.61 mg/dl) compared with diabetic patients (0.87 mg/dl). Moreover, a significant correlation between hs-CRP and hs-troponin T was also recorded (P<0.001). However, there was no significant difference in the mean hs-CRP values in patients with or without mortality. It is considered that the present study will increase the understanding of atherosclerosis in general and may also have clinical applications in the targeting of therapy for this harmful disease. PMID:28105138

  11. 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

  12. High voltage spheres in an unmagnetized plasma - Fluid and PIC simulations

    NASA Technical Reports Server (NTRS)

    Thiemann, H.; Ma, T.-Z.; Schunk, R. W.

    1992-01-01

    The basic physics involving the interaction of a high voltage sphere with a LEO-Plasma was investigated via computer experiments. Two approaches were used: the fluid description and the more general particle pushing method. Both techniques displayed qualitatively similar features. Thus, the initial time-dependent response of the plasma predicted by the fluid model, including the initial current surge and sheath formation, the formation of ion and electron density shells about the sphere with a double layer potential structure, and the subsequent propagation of the density shells away from the sphere. The PIC results also displayed an oscillatory character and slightly different time constants for the growth and decay mechanisms involved.

  13. High-rate reactive magnetron sputtering of zirconia films for laser optics applications

    NASA Astrophysics Data System (ADS)

    Juškevičius, K.; Audronis, M.; Subačius, A.; Drazdys, R.; Juškėnas, R.; Matthews, A.; Leyland, A.

    2014-09-01

    ZrO2 exhibits low optical absorption in the near-UV range and is one of the highest laser-induced damage threshold (LIDT) materials; it is, therefore, very attractive for laser optics applications. This paper reports explorations of reactive sputtering technology for deposition of ZrO2 films with low extinction coefficient k values in the UV spectrum region at low substrate temperature. A high deposition rate (64 % of the pure metal rate) process is obtained by employing active feedback reactive gas control which creates a stable and repeatable deposition processes in the transition region. Substrate heating at 200 °C was found to have no significant effect on the optical ZrO2 film properties. The addition of nitrogen to a closed-loop controlled process was found to have mostly negative effects in terms of deposition rate and optical properties. Open-loop O2 gas-regulated ZrO2 film deposition is slow and requires elevated (200 °C) substrate temperature or post-deposition annealing to reduce absorption losses. Refractive indices of the films were distributed in the range n = 2.05-2.20 at 1,000 nm and extinction coefficients were in the range k = 0.6 × 10-4 and 4.8 × 10-3 at 350 nm. X-ray diffraction analysis showed crystalline ZrO2 films consisted of monoclinic + tetragonal phases when produced in Ar/O2 atmosphere and monoclinic + rhombohedral or a single rhombohedral phase when produced in Ar/O2 + N2. Optical and physical properties of the ZrO2 layers produced in this study are suitable for high-power laser applications in the near-UV range.

  14. Spatial High-Speed-Imaging of Projectile Impacts into Fluids in Microgravity

    NASA Astrophysics Data System (ADS)

    Holfeld, B.; Maier, F.; Izzo, M.; Dinardo, S.

    2009-01-01

    Impacts of rigid metal projectiles into fluid targets were observed under microgravity conditions using a technique which simultaneously generates multiple images from different angles with microsecond resolution. The impact experiments were performed with velocities of 15 ± 3 km/h into a water surface on the ground and during parabolic flights. To obtain comparable impacts, the fluid was forced to maintain a planar surface in weightlessness by a sharp metal ring attached in a transparent ultrahydrophobic-coated cylinder. The resulting continuous `Frozen Reality'® camera pan shots show the liquid surface deformation due to projectile water-entry. While an impacted liquid surface in gravity forms a wine-glass-shaped air cavity, in microgravity, the air cavity is tear-drop-shaped. Shortly after the impact into liquid, the air cavity closes and a large air bubble remains in the fluid due to microgravity. The escaped fluid forms a columnar liquid jet which tears approximately one second after the impact and leaves a satellite drop above the impact surface. The experiments help to understand collisions of kilometer-sized low-gravity bodies in space as they behave fluid-like at high impact velocities.

  15. Reduced carbonic fluid and possible nature of high-K magmas of Tolbachik

    NASA Astrophysics Data System (ADS)

    Simakin, Alexander; Salova, Tamara; Devyatova, Vera; Zelensky, Michael

    2015-12-01

    Historical basaltic eruptions of Tolbachik volcano (Kamchatka) are of a medium to high potassic type. The potassic character of magmatism can be attributed to the influence of CO2-CO-rich fluid at or near the magma generation depths. Decarbonatization reactions in the mantle under Tolbachik producing a column of the carbonic fluids may be connected with the recent accretion of Kronotsky paleoarc with carbonates dragged under the mantle wedge. With thermodynamic modeling, we show that reduced carbonic fluid at fO2 < NNO may be a good carrier of nickel transported in the form of Ni(CO)4. This carbonyl is expected to become thermally stable near the magmatic temperatures at pressures above 1 GPa. In the crust, it is predicted to be thermally stable within the PT field of the amphibolite facies. We connect the particles of native Ni and Ag-Pt alloy observed in the volcanic aerosols from the 2012-13 Tolbachik eruption with flushing of the ascending Tolbachik magma with reduced carbonic fluids enriched with PGE and Ni. Native metals may form by the thermal decomposition of the carbonyls and other carbon-bearing compounds dissolved in the fluid.

  16. Deep-sea hydrothermal vent animals seek cool fluids in a highly variable thermal environment.

    PubMed

    Bates, Amanda E; Lee, Raymond W; Tunnicliffe, Verena; Lamare, Miles D

    2010-05-04

    The thermal characteristics of an organism's environment affect a multitude of parameters, from biochemical to evolutionary processes. Hydrothermal vents on mid-ocean ridges are created when warm hydrothermal fluids are ejected from the seafloor and mixed with cold bottom seawater; many animals thrive along these steep temperature and chemical gradients. Two-dimensional temperature maps at vent sites have demonstrated order of magnitude thermal changes over centimetre distances and at time intervals from minutes to hours. To investigate whether animals adapt to this extreme level of environmental variability, we examined differences in the thermal behaviour of mobile invertebrates from aquatic habitats that vary in thermal regime. Vent animals were highly responsive to heat and preferred much cooler fluids than their upper thermal limits, whereas invertebrates from other aquatic environments risked exposure to warmer temperatures. Avoidance of temperatures well within their tolerated range may allow vent animals to maintain a safety margin against rapid temperature fluctuations and concomitant toxicity of hydrothermal fluids.

  17. X-ray Compton scattering experiments for fluid alkali metals at high temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Matsuda, K.; Fukumaru, T.; Kimura, K.; Tamura, K.; Katoh, M.; Kajihara, Y.; Inui, M.; Yao, M.; Itou, M.; Sakurai, Y.

    2015-08-01

    We have developed a high-pressure vessel and a cell for x-ray Compton scattering measurements of fluid alkali metals. Measurements have been successfully carried out for alkali metal rubidium at elevated temperatures and pressures using synchrotron radiation at SPring-8. The width of Compton profiles (CPs) of fluid rubidium becomes narrow with decreasing fluid density, which indicates that the CPs sensitively detect the effect of reduction in the valence electron density. At the request of all authors of the paper, and with the agreement of the Proceedings Editor, an updated version of this article was published on 10 September 2015. The original article supplied to AIP Publishing was not the final version and contained PDF conversion errors in Formulas (1) and (2). The errors have been corrected in the updated and re-published article.

  18. X-ray Compton scattering experiments for fluid alkali metals at high temperatures and pressures

    SciTech Connect

    Matsuda, K. Fukumaru, T.; Kimura, K.; Yao, M.; Tamura, K.; Katoh, M.; Kajihara, Y.; Inui, M.; Itou, M.; Sakurai, Y.

    2015-08-17

    We have developed a high-pressure vessel and a cell for x-ray Compton scattering measurements of fluid alkali metals. Measurements have been successfully carried out for alkali metal rubidium at elevated temperatures and pressures using synchrotron radiation at SPring-8. The width of Compton profiles (CPs) of fluid rubidium becomes narrow with decreasing fluid density, which indicates that the CPs sensitively detect the effect of reduction in the valence electron density. At the request of all authors of the paper, and with the agreement of the Proceedings Editor, an updated version of this article was published on 10 September 2015. The original article supplied to AIP Publishing was not the final version and contained PDF conversion errors in Formulas (1) and (2). The errors have been corrected in the updated and re-published article.

  19. The rapid dissipation of magnetic fields in highly conducting fluids. [in solar or stellar atmospheres

    NASA Technical Reports Server (NTRS)

    Parker, E. N.

    1982-01-01

    The dynamical conditions that exist when long straight parallel twisted flux tubes in a highly conducting fluid are packed together in a broad array are treated. It is shown that in general there is no hydrostatic equilibrium. In place of equilibrium, there is a dynamical nonequilibrium, which leads to neutral point reconnection and progressive coalescence of neighboring tubes (with the same sense of twisting); this in turn forms tubes of large diameter and reduced twist. The magnetic energy in the twisting of each tube declines toward zero, being dissipated into small-scale motions of the fluid and thence into heat. Referring to the sun, it is pointed out that the twisting and mutual wrapping is converted directly into fluid motion and heat by the dynamical nonequilibrium, so that the work done by the convection of the footpoints goes directly into heating the corona above.

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

    SciTech Connect

    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.

  1. Highly potent stem cells from full-term amniotic fluid: A realistic perspective.

    PubMed

    Hamid, Adila A; Joharry, Muhammad Khair; Mun-Fun, Hoo; Hamzah, Siti Nurusaadah; Rejali, Zulida; Yazid, Mohd Nazri; Karuppiah, Thilakavathy; Nordin, Norshariza

    2017-03-01

    Amniotic fluid (AF) is now known to harbor highly potent stem cells, making it an excellent source for cell therapy. However, most of the stem cells isolated are from AF of mid-term pregnancies in which the collection procedure involves an invasive technique termed amniocentesis. This has limited the access in getting the fluid as the technique imposes certain level of risks to the mother as well as to the fetus. Alternatively, getting AF from full-term pregnancies or during deliveries would be a better resolution. Unfortunately, very few studies have isolated stem cells from AF at this stage of gestation, the fluid that is merely discarded. The question remains whether full-term AF harbors stem cells of similar potency as of the stem cells of mid-term AF. Here, we aim to review the prospect of having this type of stem cells by first looking at the origin and contents of AF particularly during different gestation period. We will then discuss the possibility that the AF, at full term, contains a population of highly potent stem cells. These stem cells are distinct from, and probably more potent than the AF mesenchymal stem cells (AF-MSCs) isolated from full-term AF. By comparing the studies on stem cells isolated from mid-term versus full-term AF from various species, we intend to address the prospect of having highly potent amniotic fluid stem cells from AF of full-term pregnancies in human and animals.

  2. 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.

  3. Consensus and future directions on the definition of high on-treatment platelet reactivity to adenosine diphosphate.

    PubMed

    Bonello, Laurent; Tantry, Udaya S; Marcucci, Rossella; Blindt, Ruediger; Angiolillo, Dominick J; Becker, Richard; Bhatt, Deepak L; Cattaneo, Marco; Collet, Jean Philippe; Cuisset, Thomas; Gachet, Christian; Montalescot, Gilles; Jennings, Lisa K; Kereiakes, Dean; Sibbing, Dirk; Trenk, Dietmar; Van Werkum, Jochem W; Paganelli, Franck; Price, Matthew J; Waksman, Ron; Gurbel, Paul A

    2010-09-14

    The addition of clopidogrel to aspirin treatment reduces ischemic events in a wide range of patients with cardiovascular disease. However, recurrent ischemic event occurrence during dual antiplatelet therapy, including stent thrombosis, remains a major concern. Platelet function measurements during clopidogrel treatment demonstrated a variable and overall modest level of P2Y(12) inhibition. High on-treatment platelet reactivity to adenosine diphosphate (ADP) was observed in selected patients. Multiple studies have now demonstrated a clear association between high on-treatment platelet reactivity to ADP measured by multiple methods and adverse clinical event occurrence. However, the routine measurement of platelet reactivity has not been widely implemented and recommended in the guidelines. Reasons for the latter include: 1) a lack of consensus on the optimal method to quantify high on-treatment platelet reactivity and the cutoff value associated with clinical risk; and 2) limited data to support that alteration of therapy based on platelet function measurements actually improves outcomes. This review provides a consensus opinion on the definition of high on-treatment platelet reactivity to ADP based on various methods reported in the literature and proposes how this measurement may be used in the future care of patients.

  4. High-resolution temporal analysis of deep subseafloor microbial communities inhabiting basement fluids

    NASA Astrophysics Data System (ADS)

    Jungbluth, S.; Lin, H. T.; Hsieh, C. C.; Rappe, M. S.

    2014-12-01

    , demonstrating that high-quality borehole fluid samples may range up to ~45,000 cells x ml-1. This analysis helps to constrain subseafloor biomass estimates, reveals its variability in both short and long temporal scales, and provides a glimpse of the variability in microbial community structure that spans from hours to years.

  5. ET-1 increases reactive oxygen species following hypoxia and high salt diet in the mouse glomerulus

    PubMed Central

    Heimlich, J. Brett; Speed, Joshua S.; Bloom, Christopher J.; O'Connor, Paul M.; Pollock, Jennifer S.; Pollock, David M.

    2014-01-01

    Aim The current study was designed to determine whether ET-1 derived from endothelial cells contributes to oxidative stress in the glomerulus of mice subjected to a high salt diet and/or hypoxia. Methods C57BL6/J control mice or vascular endothelial cell ET-1 knockout (VEET KO) mice were subjected to three-hour exposure to hypoxia (8% O2) and or 2 weeks of high salt diet (4% NaCl) prior to metabolic cage assessment of renal function and isolation of glomeruli for determination of reactive oxygen species (ROS). Results In control mice, hypoxia significantly increased urinary protein excretion during the initial 24 hrs, but only in animals on a high salt diet. Hypoxia increased glomerular ET-1 mRNA expression in control, but not in vascular endothelial cell ET-1 knockout (VEET KO) mice. Under normoxic conditions, mice on a high salt diet had approximately 150% higher glomerular ET-1 mRNA expression compared to a normal salt diet (p<0.05). High salt diet administration significantly increased glomerular ROS production in flox control, but not in glomeruli isolated from VEET KO mice. In C57BL6/J mice, the ETA receptor selective antagonist, ABT-627, significantly attenuated the increase in glomerular ROS production produced by high salt diet. In addition, chronic infusion of C57BL6/J mice with a sub-pressor dose of ET-1 (osmotic pumps) significantly increased levels of glomerular ROS that were prevented by ETA antagonist treatment. Conclusion These data suggest that both hypoxia and a high salt diet increases glomerular ROS production via endothelial derived ET-1-ETA receptor activation and provide a potential mechanism for ET-1 induced nephropathy. PMID:25219340

  6. The exceptionally high reactivity of Cys 621 is critical for electrophilic activation of the sensory nerve ion channel TRPA1.

    PubMed

    Bahia, Parmvir K; Parks, Thomas A; Stanford, Katherine R; Mitchell, David A; Varma, Sameer; Stevens, Stanley M; Taylor-Clark, Thomas E

    2016-06-01

    Activation of the sensory nerve ion channel TRPA1 by electrophiles is the key mechanism that initiates nociceptive signaling, and leads to defensive reflexes and avoidance behaviors, during oxidative stress in mammals. TRPA1 is rapidly activated by subtoxic levels of electrophiles, but it is unclear how TRPA1 outcompetes cellular antioxidants that protect cytosolic proteins from electrophiles. Here, using physiologically relevant exposures, we demonstrate that electrophiles react with cysteine residues on mammalian TRPA1 at rates that exceed the reactivity of typical cysteines by 6,000-fold and that also exceed the reactivity of antioxidant enzymes. We show that TRPA1 possesses a complex reactive cysteine profile in which C621 is necessary for electrophile-induced binding and activation. Modeling of deprotonation energies suggests that K620 contributes to C621 reactivity and mutation of K620 alone greatly reduces the effect of electrophiles on TRPA1. Nevertheless, binding of electrophiles to C621 is not sufficient for activation, which also depends on the function of another reactive cysteine (C665). Together, our results demonstrate that TRPA1 acts as an effective electrophilic sensor because of the exceptionally high reactivity of C621.

  7. The exceptionally high reactivity of Cys 621 is critical for electrophilic activation of the sensory nerve ion channel TRPA1

    PubMed Central

    Bahia, Parmvir K.; Parks, Thomas A.; Stanford, Katherine R.; Mitchell, David A.; Varma, Sameer; Stevens, Stanley M.

    2016-01-01

    Activation of the sensory nerve ion channel TRPA1 by electrophiles is the key mechanism that initiates nociceptive signaling, and leads to defensive reflexes and avoidance behaviors, during oxidative stress in mammals. TRPA1 is rapidly activated by subtoxic levels of electrophiles, but it is unclear how TRPA1 outcompetes cellular antioxidants that protect cytosolic proteins from electrophiles. Here, using physiologically relevant exposures, we demonstrate that electrophiles react with cysteine residues on mammalian TRPA1 at rates that exceed the reactivity of typical cysteines by 6,000-fold and that also exceed the reactivity of antioxidant enzymes. We show that TRPA1 possesses a complex reactive cysteine profile in which C621 is necessary for electrophile-induced binding and activation. Modeling of deprotonation energies suggests that K620 contributes to C621 reactivity and mutation of K620 alone greatly reduces the effect of electrophiles on TRPA1. Nevertheless, binding of electrophiles to C621 is not sufficient for activation, which also depends on the function of another reactive cysteine (C665). Together, our results demonstrate that TRPA1 acts as an effective electrophilic sensor because of the exceptionally high reactivity of C621. PMID:27241698

  8. 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

  9. Geochemistry of Multicomponent Fluid Phases in the Krafla High-Enthalpy Geothermal System, NE Iceland

    NASA Astrophysics Data System (ADS)

    Hermanska, M.; Stefansson, A.

    2014-12-01

    Many active volcanic systems are associated with high-enthalpy geothermal systems. For systems characterized by shallow magmatic intrusions, liquid water often predominates at depth with two-phase fluids, vapor and liquid water, occurring at shallower depth due to depressurization boiling. Close to the intrusion, superheated or supercritical vapor may also occur. The Krafla high-enthalpy geothermal system provides an ideal opportunity to study such volcanic geothermal systems. Over forty wells have been drilled into the system with fluid discharge temperatures of <200°C to ~450°C and enthalpy between <900 and >3200 kJ/kg. In this study, geochemical modelling of multicomponent fluid phases associated with shallow magmatic intrusions were conducted across variable temperature, pressure and enthalpy conditions and the results compared with the fluid geochemistry of the Krafla system. Within the reservoir at geothermal temperatures (250-300°C) liquid water predominates. Under these conditions, the concentrations of most major elements are controlled by equilibrium with secondary minerals. Geochemical modelling and observations at Krafla support these findings. Around the magma intrusions believed to be at shallow depth at Krafla, superheated vapor is formed. Such fluid was discharged by the IDDP-1 well at 450°C and 140 bar. According to the geochemical modelling, superheated vapor is produced upon heat addition by the intrusion to the surrounding geothermal water resulting in boiling to dryness, precipitation of non-volatiles (Si, Fe, Mg, Al, SO4, Na, K, Ca) whereas volatiles (CO2, H2S, Cl, F, B) are unaffected. By mass, quartz is the predominant secondary mineral around the intrusions. The chemical composition of the modelled and observed superheated vapor compared well. Upon ascent and depressurization of the liquid geothermal water and the superheated vapor various processes may occur, including superheated vapor condensation, mixing and depressurization boiling

  10. 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.

  11. [Cardiovascular reactivity to emotional texts in subjects with low and high level of psychoticism].

    PubMed

    Lysenko, N E; Davydov, D M

    2011-01-01

    The article presents the results of comparative study of groups of subjects with low and high level of psychoticism. Heart rate, heart rate responses to inspiratory and expiratory Valsalva maneuvers, and blood pressure were measured before and after presentation of the texts with validated negative content in groups of subjects with low and high psychoticism scores. It was hypothesized that subjects with high level of psychoticism would be less engaged in the processing of negative contents of the texts and their physiological reactivity (physiological resources submitted for support of cognitive processing) would be less pronounced compared to subjects with low level of psychoticism. Significant main effect of psychoticism was obtained for changes in heart rate to expiratory Valsalva maneuver after presentations of the texts. Significant interaction effects of gender and psychoticism were obtained for systolic blood pressure. Other cardiovascular variables were not sensitive to the level of psychoticism. These effects of psychoticism were independent of other individual traits, such as neuroticism, extraversion, lie (social desirability), anger, trait anxiety and depression.

  12. Blueberry intervention improves vascular reactivity and lowers blood pressure in high-fat-, high-cholesterol-fed rats.

    PubMed

    Rodriguez-Mateos, Ana; Ishisaka, Akari; Mawatari, Kazuaki; Vidal-Diez, Alberto; Spencer, Jeremy P E; Terao, Junji

    2013-05-28

    Growing evidence suggests that intake of flavonoid-containing foods may exert cardiovascular benefits in human subjects. We have investigated the effects of a 10-week blueberry (BB) supplementation on blood pressure (BP) and vascular reactivity in rats fed a high-fat/high-cholesterol diet, known to induce endothelial dysfunction. Rats were randomly assigned to follow a control chow diet, a chow diet supplemented with 2 % (w/w) BB, a high-fat diet (10 % lard; 0·5 % cholesterol) or the high fat plus BB for 10 weeks. Rats supplemented with BB showed significant reductions in systolic BP (SBP) of 11 and 14 %, at weeks 8 and 10, respectively, relative to rats fed the control chow diet (week 8 SBP: 107·5 (SEM 4·7) v. 122·2 (SEM 2·1) mmHg, P= 0·018; week 10 SBP: 115·0 (SEM 3·1) v. 132·7 (SEM 1·5) mmHg, P< 0·0001). Furthermore, SBP was reduced by 14 % in rats fed with the high fat plus 2 % BB diet at week 10, compared to those on the high-fat diet only (SBP: 118·2 (SEM 3·6) v. 139·5 (SEM 4·5) mmHg, P< 0·0001). Aortas harvested from BB-fed animals exhibited significantly reduced contractile responses (to L-phenylephrine) compared to those fed the control chow or high-fat diets. Furthermore, in rats fed with high fat supplemented with BB, aorta relaxation was significantly greater in response to acetylcholine compared to animals fed with the fat diet. These data suggest that BB consumption can lower BP and improve endothelial dysfunction induced by a high fat, high cholesterol containing diet.

  13. 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%.

  14. 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.

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

    PubMed

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

    2004-07-01

    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 degrees 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.

  16. The final stage of gravitational collapse for high density fluid medium

    SciTech Connect

    Souza, R. G.; De Campos, M.

    2013-03-25

    The High density high density fluids can be represented by a stiff matter state equation P={rho} and also by the Hagedorn state equation. The first is constructed using a lagrangian that allows bare nucleons to interact attractively via scalar meson exchange, and repulsively by a more massive vector meson exchange; the second consider that for large mass the spectrum of hadrons grows exponentially, namely {rho}(m) {approx}exp(m/T{sub H}), where T{sub H} is the Hagedorn temperature, resulting the state equation P = P{sub 0}+{rho}{sub 0}ln({rho}/{rho}{sub 0}). We study the gravitational collapse for a high density fluid, considering a Hagedorn state equation in a presence of a vacuum component.

  17. Electrophysiological indices of interference resolution covary with individual fluid intelligence: investigating reactive control processes in a 3-back working memory task.

    PubMed

    Perfetti, Bernardo; Varanese, Sara; Mancino, Elisa; Mercuri, Pasqua; Tesse, Marcello; Franciotti, Raffaella; Bonanni, Laura; Thomas, Astrid; Onofrj, Marco

    2014-06-01

    It has been proposed that the well-established relationship between working memory (WM) and fluid intelligence (gf) is mediated by executive mechanisms underlying interference control. The latter relies upon the integrity of a frontoparietal brain network, whose activity is modulated by general cognition. In regards to the chronology of this activation, only few EEG studies investigated the topic, although none of them examined the regional interaction or the effects of individual differences in gf. The current investigation sought at extending previous research by characterizing the EEG markers (temporal activation and regional coupling) of interference control and the effects of the individual variation in gf. To this end, we recorded the EEG activity of 33 participants while performing verbal and spatial versions of a 3-back WM task. In a separate session, participants were administered with a test of fluid intelligence. Interference-inducing trials were associated with an increased negativity in the frontal scalp region occurring in two separate time windows and probably reflecting two different stages of the underlying cognitive process. In addition, we found that scalp distribution of such activity differed among individuals, being the strongest activation of the left and right frontolateral sites related to high gf level. Finally, high- and low-gf participants showed different patterns in the modulation of regional connectivity (electrodes coherence in the range of 4.5-7.5Hz) according to changes in attention load among types of trials. Our findings suggest that high-gf participants may rely upon effective engagement and modulation of attention resources to face interference.

  18. Shock compression response of highly reactive Ni + Al multilayered thin foils

    NASA Astrophysics Data System (ADS)

    Kelly, Sean C.; Thadhani, Naresh N.

    2016-03-01

    The shock-compression response of Ni + Al multilayered thin foils is investigated using laser-accelerated thin-foil plate-impact experiments over the pressure range of 2 to 11 GPa. The foils contain alternating Ni and Al layers (parallel but not flat) of nominally 50 nm bilayer spacing. The goal is to determine the equation of state and shock-induced reactivity of these highly reactive fully dense thin-foil materials. The laser-accelerated thin-foil impact set-up involved combined use of photon-doppler-velocimetry to monitor the acceleration and impact velocity of an aluminum flyer, and VISAR interferometry was used to monitor the back free-surface velocity of the impacted Ni + Al multilayered target. The shock-compression response of the Ni + Al target foils was determined using experimentally measured parameters and impedance matching approach, with error bars identified considering systematic and experimental errors. Meso-scale CTH shock simulations were performed using real imported microstructures of the cross-sections of the multilayered Ni + Al foils to compute the Hugoniot response (assuming no reaction) for correlation with their experimentally determined equation of state. It was observed that at particle velocities below ˜150 m/s, the experimentally determined equation of state trend matches the CTH-predicted inert response and is consistent with the observed unreacted state of the recovered Ni + Al target foils from this velocity regime. At higher particle velocities, the experimentally determined equation of state deviates from the CTH-predicted inert response. A complete and self-sustained reaction is also seen in targets recovered from experiments performed at these higher particle velocities. The deviation in the measured equation of state, to higher shock speeds and expanded volumes, combined with the observation of complete reaction in the recovered multilayered foils, confirmed via microstructure characterization, is indicative of the occurrence

  19. 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

  20. [Plasma concentration of C-reactive protein in patients with high estrogen levels].

    PubMed

    Ricoux, R; Pontet, M; Tresca, J P; Engler, R

    1994-01-01

    The monitoring of inflammatory activity in patients with a high level of estrogen is controversial because the significance of a raised estradiol level on C-reactive protein (CRP) concentrations is a debated question. This prompted us to assay CRP by a sensitive Elisa in a sample of 30 patients with ovarian stimulation for in vitro fertilization, thus with high levels of estradiol. For 15 of these women, six to nine plasma samples were analyzed allowing a kinetic study of plasma levels of CRP, estradiol and sex steroid-binding plasma protein (SBP). No significant correlation was found between the concentrations of estradiol and CRP for the 30 patients. In the kinetic study, as mean estradiol levels rose exponentially from 50 to 1400 ng/l between day 5 and 14, the CRP level tended to vary markedly from one patient to another and sometimes from day to day, but there was never any relation with estradiol level. Furthermore, CRP did not significantly modify the slope of the regression line between estradiol concentration and the day of the menstrual cycle. In contrast, the effect of estradiol on SBP was clear, which supports the absence of estradiol effect on CRP level.

  1. Reactively-sputtered zinc semiconductor films of high conductivity for heterojunction devices

    NASA Technical Reports Server (NTRS)

    Stirn, Richard J. (Inventor)

    1986-01-01

    A high conductivity, n-doped semiconductor film is produced from zinc, or Zn and Cd, and group VI elements selected from Se, S and Te in a reactive magnetron sputtering system having a chamber with one or two targets, a substrate holder, means for heating the substrate holder, and an electric field for ionizing gases in the chamber. Zinc or a compound of Zn and Cd is placed in the position of one of the two targets and doping material in the position of the other of the two targets. Zn and Cd may be placed in separate targets while a dopant is placed in the third target. Another possibility is to place an alloy of Zn and dopant, or Zn, Cd and dopant in one target, thus using only one target. A flow of the inert gas is ionized and directed toward said targets, while a flow of a reactant gas consisting of hydrides of the group VI elements is directed toward a substrate on the holder. The targets are biased to attract negatively ionized inert gas. The desired stochiometry for high conductivity is achieved by controlling the temperature of the substrate, and partial pressures of the gases, and the target power and total pressure of the gases in the chamber.

  2. Combined AFM nano-machining and reactive ion etching to fabricate high aspect ratio structures.

    PubMed

    Peng, Ping; Shi, Tielin; Liao, Guanglan; Tang, Zirong

    2010-11-01

    In this paper, a new combined method of sub-micron high aspect ratio structure fabrication is developed which can be used for production of nano imprint template. The process includes atomic force microscope (AFM) scratch nano-machining and reactive ion etching (RIE) fabrication. First, 40 nm aluminum film was deposited on the silicon substrate by magnetron sputtering, and then sub-micron grooves were fabricated on the aluminum film by nano scratch using AFM diamond tip. As aluminum film is a good mask for etching silicon, high aspect ratio structures were finally fabricated by RIE process. The fabricated structures were studied by SEM, which shows that the grooves are about 400 nm in width and 5 microm in depth. To obtain sub-micron scale groove structures on the aluminum film, experiments of nanomachining on aluminum films under various machining conditions were conducted. The depths of the grooves fabricated using different scratch loads were also studied by the AFM. The result shows that the material properties of the film/substrate are elastic-plastic following nearly a bilinear law with isotropic strain hardening. Combined AFM nanomachining and RIE process provides a relative lower cost nano fabrication technique than traditional e-beam lithography, and it has a good prospect in nano imprint template fabrication.

  3. Pebble Fuel Handling and Reactivity Control for Salt-Cooled High Temperature Reactors

    SciTech Connect

    Peterson, Per; Greenspan, Ehud

    2015-02-09

    This report documents the work completed on the X-PREX facility under NEUP Project 11- 3172. This project seeks to demonstrate the viability of pebble fuel handling and reactivity control for fluoride salt-cooled high-temperature reactors (FHRs). The research results also improve the understanding of pebble motion in helium-cooled reactors, as well as the general, fundamental understanding of low-velocity granular flows. Successful use of pebble fuels in with salt coolants would bring major benefits for high-temperature reactor technology. Pebble fuels enable on-line refueling and operation with low excess reactivity, and thus simpler reactivity control and improved fuel utilization. If fixed fuel designs are used, the power density of salt- cooled reactors is limited to 10 MW/m3 to obtain adequate duration between refueling, but pebble fuels allow power densities in the range of 20 to 30 MW/m3. This can be compared to the typical modular helium reactor power density of 5 MW/m3. Pebble fuels also permit radial zoning in annular cores and use of thorium or graphite pebble blankets to reduce neutron fluences to outer radial reflectors and increase total power production. Combined with high power conversion efficiency, compact low-pressure primary and containment systems, and unique safety characteristics including very large thermal margins (>500°C) to fuel damage during transients and accidents, salt-cooled pebble fuel cores offer the potential to meet the major goals of the Advanced Reactor Concepts Development program to provide electricity at lower cost than light water reactors with improved safety and system performance.This report presents the facility description, experimental results, and supporting simulation methods of the new X-Ray Pebble Recirculation Experiment (X-PREX), which is now operational and being used to collect data on the behavior of slow dense granular flows relevant to pebble bed reactor core designs. The X

  4. Application of LC-high-resolution MS with 'intelligent' data mining tools for screening reactive drug metabolites.

    PubMed

    Ma, Shuguang; Chowdhury, Swapan K

    2012-03-01

    Biotransformation of chemically stable compounds to reactive metabolites that can bind covalently to macromolecules (such as proteins and DNA) is considered an undesirable property of drug candidates. Due to the possible link, which has not yet been conclusively demonstrated, between reactive metabolites and adverse drug reactions, screening for metabolic activation of lead compounds through in vitro chemical trapping experiments has become an integral part of the drug discovery process in many laboratories. In this review, we provide an overview of the recent advances in the application of high-resolution MS. These advances facilitated the development of accurate-mass-based data mining tools for high-throughput screening of reactive drug metabolites in drug discovery.

  5. Abnormally high fluid pressures in the region of the Coalinga earthquake sequence and their significance

    SciTech Connect

    Yerkes, R.F.; Levine, P.; Wentworth, C.M.

    1990-01-01

    Abnormally high fluid pressures (AHP's) permitted or aided thrusting of buried tectonic wedges of Franciscan assemblage eastward beneath coeval Great Valley sequence onto mafic basement and thus contributed to the 1983 Coalinga earthquake sequence. Much of the southwestern San Joaquin Valley and adjoining parts of the Diablo Range are underlain by rocks with pressure/depth (P/D) ratios near or greater than 0.5 psi/ft (the hydrostatic gradient for oil-field waters is about 0.47 psi/ft). Plots of P/D ratio versus depth for more than 300 wells show an average ratio of about 0.6 psi/ft above 14,000-ft depth, a lower bound of 0.47 psi/ft, and an upper bound greater than 0.9 psi/ft; ratios greater than 0.60 psi/ft are interpreted to be abnormally high. Several likely sources of AHP's are recognized, but their relative contributions cannot be determined. Chief of these sources are diagenetic-metamorphic generation of fluids in the Great Valley sequence and Franciscan rocks, compaction disequilibrium and aquathermal pressuring in Tertiary strata, and horizontal tectonic compression. Yerkes, Levine, and Wentworth infer the presence of near-lithostatic fluid pressures in the Great Valley sequence and Franciscan rocks below the Coalinga anticline on the basis of (1) a mapped seismic low-velocity zone; (2) active generation of metamorphic fluids in the Great Valley sequence and Franciscan rocks, which pond below relatively impermeable layers and thus increase fluid pressure; and (3) apparent southward and westward propagation of the 1983 main-shock rupture, which indicates rupture on a gently southwest dipping surface and implies an inverse relation between depth and crustal strength.

  6. On the isosteric heat of adsorption of non-polar and polar fluids on highly graphitized carbon black.

    PubMed

    Horikawa, Toshihide; Zeng, Yonghong; Do, D D; Sotowa, Ken-Ichiro; Alcántara Avila, Jesús Rafael

    2015-02-01

    Isosteric heat of adsorption is indispensable in probing the energetic behavior of interaction between adsorbate and solid, and it can shed insight into how molecules interact with a solid by studying the dependence of isosteric heat on loading. In this study, we illustrated how this can be used to explain the difference between adsorption of non-polar (and weakly polar) fluids and strong polar fluids on a highly graphitized carbon black, Carbopack F. This carbon black has a very small quantity of functional group, and interestingly we showed that no matter how small it is the analysis of the isosteric heat versus loading can identify its presence and how it affects the way polar molecules adsorb. We used argon and nitrogen as representatives of non-polar fluid and weakly polar fluid, and methanol and water for strong polar fluid. The pattern of the isosteric heat versus loading can be regarded as a fingerprint to determine the mechanism of adsorption for strong polar fluids, which is very distinct from that for non-polar fluids. This also allows us to estimate the interplay between the various interactions: fluid-fluid, fluid-basal plane and fluid-functional group.

  7. Highly reactive {001} facets of TiO2-based composites: synthesis, formation mechanism and characterization.

    PubMed

    Ong, Wee-Jun; Tan, Lling-Lling; Chai, Siang-Piao; Yong, Siek-Ting; Mohamed, Abdul Rahman

    2014-02-21

    Titanium dioxide (TiO2) is one of the most widely investigated metal oxides due to its extraordinary surface, electronic and catalytic properties. However, the large band gap of TiO2 and massive recombination of photogenerated electron-hole pairs limit its photocatalytic and photovoltaic efficiency. Therefore, increasing research attention is now being directed towards engineering the surface structure of TiO2 at the most fundamental and atomic level namely morphological control of {001} facets in the range of microscale and nanoscale to fine-tune its physicochemical properties, which could ultimately lead to the optimization of its selectivity and reactivity. The synthesis of {001}-faceted TiO2 is currently one of the most active interdisciplinary research areas and demonstrations of catalytic enhancement are abundant. Modifications such as metal and non-metal doping have also been extensively studied to extend its band gap to the visible light region. This steady progress has demonstrated that TiO2-based composites with {001} facets are playing and will continue to play an indispensable role in the environmental remediation and in the search for clean and renewable energy technologies. This review encompasses the state-of-the-art research activities and latest advancements in the design of highly reactive {001} facet-dominated TiO2via various strategies, including hydrothermal/solvothermal, high temperature gas phase reactions and non-hydrolytic alcoholysis methods. The stabilization of {001} facets using fluorine-containing species and fluorine-free capping agents is also critically discussed in this review. To overcome the large band gap of TiO2 and rapid recombination of photogenerated charge carriers, modifications are carried out to manipulate its electronic band structure, including transition metal doping, noble metal doping, non-metal doping and incorporating graphene as a two-dimensional (2D) catalyst support. The advancements made in these aspects are

  8. A highly reactive chalcogenide precursor for the synthesis of metal chalcogenide quantum dots

    NASA Astrophysics Data System (ADS)

    Jiang, Peng; Zhu, Dong-Liang; Zhu, Chun-Nan; Zhang, Zhi-Ling; Zhang, Guo-Jun; Pang, Dai-Wen

    2015-11-01

    Metal chalcogenide semiconductor nanocrystals (NCs) are ideal inorganic materials for solar cells and biomedical labeling. In consideration of the hazard and instability of alkylphosphines, the phosphine-free synthetic route has become one of the most important trends in synthesizing selenide QDs. Here we report a novel phase transfer strategy to prepare phosphine-free chalcogenide precursors. The anions in aqueous solution were transferred to toluene via electrostatic interactions between the anions and didodecyldimethylammonium bromide (DDAB). The obtained chalcogenide precursors show high reactivity with metal ions in the organic phase and could be applied to the low-temperature synthesis of various metal chalcogenide NCs based on a simple reaction between metal ions (e.g. Ag+, Pb2+, Cd2+) and chalcogenide anions (e.g. S2-) in toluene. In addition to chalcogenide anions, other anions such as BH4- ions and AuCl4- ions can also be transferred to the organic phase for synthesizing noble metal NCs (such as Ag and Au NCs).Metal chalcogenide semiconductor nanocrystals (NCs) are ideal inorganic materials for solar cells and biomedical labeling. In consideration of the hazard and instability of alkylphosphines, the phosphine-free synthetic route has become one of the most important trends in synthesizing selenide QDs. Here we report a novel phase transfer strategy to prepare phosphine-free chalcogenide precursors. The anions in aqueous solution were transferred to toluene via electrostatic interactions between the anions and didodecyldimethylammonium bromide (DDAB). The obtained chalcogenide precursors show high reactivity with metal ions in the organic phase and could be applied to the low-temperature synthesis of various metal chalcogenide NCs based on a simple reaction between metal ions (e.g. Ag+, Pb2+, Cd2+) and chalcogenide anions (e.g. S2-) in toluene. In addition to chalcogenide anions, other anions such as BH4- ions and AuCl4- ions can also be transferred to

  9. Increased frequency of {gamma}{delta} T cells in cerebrospinal fluid and peripheral blood of patients with multiple sclerosis: Reactivity, cytotoxicity, and T cell receptor V gene rearrangements

    SciTech Connect

    Stinissen, P.; Vandevyver, C.; Medaer, R.

    1995-05-01

    Infiltrating {gamma}{delta} T cells are potentially involved in the central nervous system demyelination in multiple sclerosis (MS). To further study this hypothesis, we analyzed the frequency and functional properties of {gamma}{delta} T cells in peripheral blood (PB) and paired cerebrospinal fluid (CSF) of patients with MS and control subjects, including patients with other neurologic diseases (OND) and healthy individuals. The frequency analysis was performed under limiting dilution condition using rIL-2 and PHA. After PHA stimulation, a significantly increased frequency of {gamma}{delta} T cells was observed in PB and in CSF of MS patients as compared with PB and CSF of patients with OND. The frequency was represented equally in OND patients and normal individuals. Similarly, the IL-2-responsive {gamma}{delta} T cells occurred at a higher frequency in PB of MS than of control subjects. Forty-three percent of the {gamma}{delta} T cell clones isolates from PB and CSF of MS patients responded to heat shock protein (HSP70) but not HSP65, whereas only 2 of 30 control {gamma}{delta} T cell clones reacted to the HSP. The majority of the {gamma}{delta} T cell clones were able to induce non-MHC-restricted cytolysis of Daudi cells. All clones displayed a substantial reactivity to bacterial superantigens staphylococcal enterotoxin B and toxic shock syndrome toxin-1, irrespective of their {gamma}{delta} V gene usage. Furthermore, the {gamma}{delta} T cell clones expressed predominantly TCRDV2 and GV2 genes, whereas the clones derived from CSF of MS patients expressed either DV1 or DV2 genes. The obtained {gamma}{delta} clones, in general, represented rather heterogeneous clonal origins, even though a predominant clonal origin was found in a set of 10 {gamma}{delta} clones derived from one patient with MS. The present study provides new evidence supporting a possible role of {gamma}{delta} T cells in the secondary inflammatory processes in MS. 39 refs., 5 figs., 4 tabs.

  10. Effect of bovine follicular fluid on reactive oxygen species and glutathione in oocytes, apoptosis and apoptosis-related gene expression of in vitro-produced blastocysts.

    PubMed

    Park, S-H; Cho, H-S; Yu, I-J

    2014-06-01

    The reactive oxygen species (ROS) generated during the in vitro maturation of oocytes affect oocyte maturation and subsequent embryonic development. Bovine follicular fluid (bFF) has an effective antioxidant capacity. This study was conducted to investigate the effects of supplementing oocyte maturation media with bFF from different size classes (3-8 and 9-13 mm) on the glutathione (GSH) and ROS levels of oocytes. Embryonic development and apoptosis, as well as the relative abundance of INFτ, BAX, BCL2 and HSP70 transcripts in blastocysts, were also monitored. Oocytes collected from ovaries were matured in TCM-199 with FBS (control) and 10% 3-8 mm (M), 9-13 mm (L) or a mixture of 3-8 mm and 9-13 mm (M + L) bFF. Glutathione and ROS levels in oocytes after 24 h were assessed by Cell Tracker Blue CMF2HC and DCHFDA staining, respectively. Apoptosis in day-8 blastocysts was assessed by TUNEL staining. The relative abundance of BAX, BCL2, HSP70 and INFτ transcripts was assessed using quantitative real-time polymerase chain reaction (PCR). The GSH level was significantly higher in the L group compared to the other groups (p < 0.05), while the ROS levels in the M group were significantly higher than in the other groups (p < 0.05). The apoptosis levels of blastocysts in the FBS group were significantly higher than those in the M + L group (p < 0.05), although the embryonic development did not differ between the groups. The HSP70 and INFτ expression levels in group M were significantly greater than in the controls (p < 0.05). There was no significant difference in BAX expression between the groups. Supplementation with bFF from various sizes of follicles into the maturation medium was capable of supporting oocyte cytoplasmic maturation by decreasing the ROS. Moreover, bFF subsequently affected antioxidative gene expression, increasing HSP70 and INFτ expressions.

  11. Impact of scaling and root planing on C-reactive protein levels in gingival crevicular fluid and serum in chronic periodontitis patients with or without diabetes mellitus

    PubMed Central

    2014-01-01

    Purpose The present study was conducted to evaluate the impact of scaling and root planing (SRP) on the C-reactive protein (CRP) levels of gingival crevicular fluid (GCF) and serum in chronic periodontitis patients with type 2 diabetes mellitus (T2DM-CP) or without type 2 diabetes mellitus (NDM-CP). Methods Forty-eight human participants were divided into two groups: an experimental (T2DM-CP) group (group I, n=24) comprising chronic periodontitis patients with random blood sugar ≥200 mg/dL and type 2 diabetes mellitus, and control (NDM-CP) group (group II, n=24) of those with chronic periodontitis and random blood sugar <200 without T2DM for the study. All subjects underwent nonsurgical periodontal therapy (NSPT) including complete SRP and subgingival debridement. Periodontal health parameters, plaque index (PI), gingival index (GI), probing pocket depth (PPD), clinical attachment level (CAL), GCF volume (GCF vol), GCF-CRP, random blood glucose (RBS), glycated hemoglobin, and systemic inflammatory markers, serum CRP, total leukocyte count (TLC), neutrophil count (Neutr) and lymphocyte count (Lymph), were evaluated at baseline, 1 month, and 3 months after SRP. Results NSPT resulted in statistically significant improvement in periodontal health parameters (PI, GI, PPD, CAL, GCF vol), CRP levels in serum as well as GCF of both groups I and II. The mean improvement in periodontal health parameters (PI, GI, PPD, CAL, GCF vol), CRP levels in serum and GCF was greater in group I than group II after NSPT. There was nonsignificant increase in GCF-CRP, TLC, Lymph, and RBS, and a significant increase in Neutr and Serum CRP in group II at 1 month. The Serum CRP level of 20 out of 24 group II patients had also increased at 1 month. Conclusions The CRP levels in both GCF and serum were higher in T2DM-CP patients than in NDM-CP patients. Although there was a significant improvement in both the groups, greater improvement was observed in both GCF and serum samples of T2DM

  12. Alpha reactivity to first names differs in subjects with high and low dream recall frequency.

    PubMed

    Ruby, Perrine; Blochet, Camille; Eichenlaub, Jean-Baptiste; Bertrand, Olivier; Morlet, Dominique; Bidet-Caulet, Aurélie

    2013-01-01

    Studies in cognitive psychology showed that personality (openness to experience, thin boundaries, absorption), creativity, nocturnal awakenings, and attitude toward dreams are significantly related to dream recall frequency (DRF). These results suggest the possibility of neurophysiological trait differences between subjects with high and low DRF. To test this hypothesis we compared sleep characteristics and alpha reactivity to sounds in subjects with high and low DRF using polysomnographic recordings and electroencephalography (EEG). We acquired EEG from 21 channels in 36 healthy subjects while they were presented with a passive auditory oddball paradigm (frequent standard tones, rare deviant tones and very rare first names) during wakefulness and sleep (intensity, 50 dB above the subject's hearing level). Subjects were selected as High-recallers (HR, DRF = 4.42 ± 0.25 SEM, dream recalls per week) and Low-recallers (LR, DRF = 0.25 ± 0.02) using a questionnaire and an interview on sleep and dream habits. Despite the disturbing setup, the subjects' quality of sleep was generally preserved. First names induced a more sustained decrease in alpha activity in HR than in LR at Pz (1000-1200 ms) during wakefulness, but no group difference was found in REM sleep. The current dominant hypothesis proposes that alpha rhythms would be involved in the active inhibition of the brain regions not involved in the ongoing brain operation. According to this hypothesis, a more sustained alpha decrease in HR would reflect a longer release of inhibition, suggesting a deeper processing of complex sounds than in LR during wakefulness. A possibility to explain the absence of group difference during sleep is that increase in alpha power in HR may have resulted in awakenings. Our results support this hypothesis since HR experienced more intra sleep wakefulness than LR (30 ± 4 vs. 14 ± 4 min). As a whole our results support the hypothesis of neurophysiological trait differences in high and

  13. Alpha reactivity to first names differs in subjects with high and low dream recall frequency

    PubMed Central

    Ruby, Perrine; Blochet, Camille; Eichenlaub, Jean-Baptiste; Bertrand, Olivier; Morlet, Dominique; Bidet-Caulet, Aurélie

    2013-01-01

    Studies in cognitive psychology showed that personality (openness to experience, thin boundaries, absorption), creativity, nocturnal awakenings, and attitude toward dreams are significantly related to dream recall frequency (DRF). These results suggest the possibility of neurophysiological trait differences between subjects with high and low DRF. To test this hypothesis we compared sleep characteristics and alpha reactivity to sounds in subjects with high and low DRF using polysomnographic recordings and electroencephalography (EEG). We acquired EEG from 21 channels in 36 healthy subjects while they were presented with a passive auditory oddball paradigm (frequent standard tones, rare deviant tones and very rare first names) during wakefulness and sleep (intensity, 50 dB above the subject's hearing level). Subjects were selected as High-recallers (HR, DRF = 4.42 ± 0.25 SEM, dream recalls per week) and Low-recallers (LR, DRF = 0.25 ± 0.02) using a questionnaire and an interview on sleep and dream habits. Despite the disturbing setup, the subjects' quality of sleep was generally preserved. First names induced a more sustained decrease in alpha activity in HR than in LR at Pz (1000–1200 ms) during wakefulness, but no group difference was found in REM sleep. The current dominant hypothesis proposes that alpha rhythms would be involved in the active inhibition of the brain regions not involved in the ongoing brain operation. According to this hypothesis, a more sustained alpha decrease in HR would reflect a longer release of inhibition, suggesting a deeper processing of complex sounds than in LR during wakefulness. A possibility to explain the absence of group difference during sleep is that increase in alpha power in HR may have resulted in awakenings. Our results support this hypothesis since HR experienced more intra sleep wakefulness than LR (30 ± 4 vs. 14 ± 4 min). As a whole our results support the hypothesis of neurophysiological trait differences in high

  14. 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

  15. Transferable SAFT-VR models for the calculation of the fluid phase equilibria in reactive mixtures of carbon dioxide, water, and n-alkylamines in the context of carbon capture.

    PubMed

    Mac Dowell, N; Pereira, F E; Llovell, F; Blas, F J; Adjiman, C S; Jackson, G; Galindo, A

    2011-06-30

    The amine functional groups are fundamental building blocks of many molecules that are central to life, such as the amino acids, and to industrial processes, such as the alkanolamines, which are used extensively for gas absorption. The modeling of amines and of mixtures of amines with water (H(2)O) and carbon dioxide (CO(2)) is thus relevant to a number of applications. In this contribution, we use the statistical associating fluid theory for potentials of variable range (SAFT-VR) to describe the fluid phase behavior of ammonia + H(2)O + CO(2) and n-alkyl-1-amine + H(2)O + CO(2) mixtures. Models are developed for ammonia (NH(3)) and n-alkyl-1-amines up to n-hexyl-1-amine (CH(3)NH(2) to C(6)H(13)NH(2)). The amines are modeled as homonuclear chain molecules formed from spherical segments with additional association sites incorporated to mediate the effect of hydrogen-bonding interactions. The SAFT-VR approach provides a representation of the pure component fluid phase equilibria, on average, to within 1.48% of the experimental data in relative terms for the saturated liquid densities and vapor pressures. A simple empirical correlation is derived for the SAFT-VR parameters of the n -alkylamine series as a function of molecular weight. Aqueous mixtures of the amines are modeled using a model of water taken from previous work. The models developed for the mixtures are of high fidelity and can be used to calculate the binary fluid phase equilibrium of these systems to within 2.28% in relative terms for the temperature or pressure and 0.027 in absolute terms for the mole fraction. Regions of both vapor-liquid and liquid-liquid equilibria are considered. We also consider the reactive mixtures of amines and CO(2) in aqueous solution. To model the reaction of CO(2) with the amine, an additional site is included on the otherwise nonassociating CO(2) model. The unlike interaction parameters for the NH(3) + H(2)O + CO(2) ternary mixture are obtained by comparison to the

  16. Highly simplified lateral flow-based nucleic acid sample preparation and passive fluid flow control

    SciTech Connect

    Cary, Robert E.

    2015-12-08

    Highly simplified lateral flow chromatographic nucleic acid sample preparation methods, devices, and integrated systems are provided for the efficient concentration of trace samples and the removal of nucleic acid amplification inhibitors. Methods for capturing and reducing inhibitors of nucleic acid amplification reactions, such as humic acid, using polyvinylpyrrolidone treated elements of the lateral flow device are also provided. Further provided are passive fluid control methods and systems for use in lateral flow assays.

  17. 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.

  18. Review of electric discharge microplasmas generated in highly fluctuating fluids: Characteristics and application to nanomaterials synthesis

    SciTech Connect

    Stauss, Sven Terashima, Kazuo; Muneoka, Hitoshi; Urabe, Keiichiro

    2015-05-15

    Plasma-based fabrication of novel nanomaterials and nanostructures is indispensible for the development of next-generation electronic devices and for green energy applications. In particular, controlling the interactions between plasmas and materials interfaces, and the plasma fluctuations, is crucial for further development of plasma-based processes and bottom-up growth of nanomaterials. Electric discharge microplasmas generated in supercritical fluids represent a special class of high-pressure plasmas, where fluctuations on the molecular scale influence the discharge properties and the possible bottom-up growth of nanomaterials. This review discusses an anomaly observed for direct current microplasmas generated near the critical point, a local decrease in the breakdown voltage. This anomalous behavior is suggested to be caused by the concomitant decrease of the ionization potential due to the formation of clusters near the critical point, and the formation of extended electron mean free paths caused by the high-density fluctuation near the critical point. It is also shown that in the case of dielectric barrier microdischarges generated close to the critical point, the high-density fluctuation of the supercritical fluid persists. The final part of the review discusses the application of discharges generated in supercritical fluids to synthesis of nanomaterials, in particular, molecular diamond—so-called diamondoids—by microplasmas generated inside conventional batch-type and continuous flow microreactors.

  19. High-pressure reactively sputtered HfO2: Composition, morphology, and optical properties

    NASA Astrophysics Data System (ADS)

    Toledano-Luque, M.; San Andrés, E.; del Prado, A.; Mártil, I.; Lucía, M. L.; González-Díaz, G.; Martínez, F. L.; Bohne, W.; Röhrich, J.; Strub, E.

    2007-08-01

    Hafnium oxide films were deposited by high pressure reactive sputtering using different deposition pressures and times. The composition, morphology, and optical properties of the films, together with the sputtering process growth kinetics were investigated using heavy ion elastic recoil detection analysis, Fourier transform infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, x-ray diffraction, and transmission electron microscopy. The films showed a monoclinic polycrystalline structure, with a grain size depending on the deposition pressure. All films were slightly oxygen rich with respect to stoichiometric HfO2 and presented a significant amount of hydrogen (up to 6at.%), which is attributed to the high affinity for moisture of the HfO2 films. The absorption coefficient was fitted to the Tauc law, obtaining a band gap value of 5.54eV. It was found that the growth rate of the HfO2 films depends on the deposition pressure (P ) as P-1.75. This dependence is explained by a diffusion model of the thermalized atoms in high-pressure sputtering. Additionally, the formation of an interfacial silicon oxide layer when the films were grown on silicon was observed, with a minimum thickness for deposition pressures around 1.2mbars. This interfacial layer was formed mainly during the initial stages of the deposition process, with only a slight increase in thickness afterwards. These results are explained by the oxidizing action of the oxygen plasma and the diffusion of oxygen radicals and hydroxyl groups through the polycrystalline HfO2 film. Finally, the dielectric properties of the HfO2/SiO2 stacks were studied by means of conductance and capacitance measurements on Al /HfO2/SiO2/Si devices as a function of gate voltage and ac frequency signal.

  20. High metal reactivity and environmental risks at a site contaminated by glass waste.

    PubMed

    Augustsson, A; Åström, M; Bergbäck, B; Elert, M; Höglund, L O; Kleja, D B

    2016-07-01

    This study addresses the reactivity and risks of metals (Ba, Cd, Co, Cr, Cu, Ni, Pb, Zn, As and Sb) at a Swedish site with large glass waste deposits. Old glassworks sites typically have high total metal concentrations, but as the metals are mainly bound within the glass waste and considered relatively inert, environmental investigations at these kinds of sites are limited. In this study, soil and landfill samples were subjected to a sequential chemical extraction procedure. Data from batch leaching tests and groundwater upstream and downstream of the waste deposits were also interpreted. The sequential extraction revealed that metals in <2 mm soil/waste samples were largely associated with geochemically active fractions, indicating that metals are released from pristine glass and subsequently largely retained in the surrounding soil and/or on secondary mineral coatings on fine glass particles. From the approximately 12,000 m(3) of coarse glass waste at the site, almost 4000 kg of Pb is estimated to have been lost through corrosion, which, however, corresponds to only a small portion of the total amount of Pb in the waste. Metal sorption within the waste deposits or in underlying soil layers is supported by fairly low metal concentrations in groundwater. However, elevated concentrations in downstream groundwater and in leachates of batch leaching tests were observed for several metals, indicating on-going leaching. Taken together, the high metal concentrations in geochemically active forms and the high amounts of as yet uncorroded metal-rich glass, indicate considerable risks to human health and the environment.

  1. Does High Alveolar Fluid Reabsorption Prevent HAPE in Individuals with Exaggerated Pulmonary Hypertension in Hypoxia?

    PubMed

    Betz, Theresa; Dehnert, Christoph; Bärtsch, Peter; Schommer, Kai; Mairbäurl, Heimo

    2015-12-01

    An exaggerated increase in pulmonary arterial systolic pressure (PAsP) is a highlight of high altitude pulmonary edema (HAPE). However, the incidence of HAPE at 4559 m was much lower in altitude-naïve individuals with exaggerated pulmonary vasoconstriction (HPV) in normobaric hypoxia than in known HAPE-susceptibles, indicating that elevated PAsP alone is insufficient to induce HAPE. A decreased nasal potential difference (NPD) has been found in HAPE-susceptibles, where, based on animal models, NPD serves as surrogate of alveolar epithelial ion transport. We hypothesize that those HAPE-resistant individuals with high HPV may be protected by elevated alveolar Na and fluid reabsorption, which might be detected as increased NPD. To test this hypothesis, we measured NPD in normoxia of subjects who were phenotyped in previous studies as high altitude tolerant (controls), known HAPE-susceptibles with high HPV (HP+HAPE), as well as individuals with high HPV but without HAPE (HP-no-HAPE) at 4559 m. NPD and amiloride-sensitive NPD were lower in HP+HAPE than in controls, whereas HP-no-HAPE were not different from either group. There were no differences in Cl-transport between groups. Our results show low nasal ion transport in HAPE but higher transport in those individuals with the highest HPV but without HAPE. This indicates that in some individuals with high PAsP at high altitude high alveolar fluid reabsorption might protect them from HAPE.

  2. Three step deep reactive ion etch for high density trench etching

    NASA Astrophysics Data System (ADS)

    Lips, B.; Puers, R.

    2016-10-01

    A three step Deep Reactive Ion Etch (DRIE) process is developed to etch trenches of 10μm wide to a depth of 130μm into silicon with an etch rate of 2.5μm min-1. The aim of this process is to obtain sidewalls with an angle close to 90°. The process allows the etching of multiple trenches with high aspect ratios that are closely placed together. A three step approach is used as opposed to the more conventional two step approach in an attempt to improve the etching selectivity with respect to the masking material. By doing so, a simple AZ6632 positive photoresist could be used instead of the more commonly used metal masks which are harder to remove afterwards. In order to develop this process, four parameters, which are the bias power, processing pressure, step times and number of cycles, are evaluated an optimized on a PlasmaPro 300 Cobra DRIE tool from Oxford Plasma Technology.

  3. Anthropogenic emissions of highly reactive volatile organic compounds inferred from oversampling of OMI HCHO columns

    NASA Astrophysics Data System (ADS)

    Zhu, L.; Jacob, D. J.; Mickley, L. J.; Marais, E. A.; Cohan, D. S.; Yoshida, Y.; Duncan, B. N.; Gonzalez Abad, G.; Chance, K.

    2014-12-01

    Satellite observations of formaldehyde (HCHO) columns provide top-down constraints on emissions of highly reactive volatile organic compounds (HRVOCs). This approach has been used previously to constrain emissions of isoprene from vegetation, but application to US anthropogenic emissions has been stymied by lack of a discernable HCHO signal. Here we show that oversampling of HCHO data from the Ozone Monitoring Instrument (OMI) for 2005-2008 enables quantitative detection of urban and industrial plumes in eastern Texas including Houston, Port Arthur, and Dallas/Fort Worth. By spatially integrating the individual urban/industrial HCHO plumes observed by OMI we can constrain the corresponding HCHO-weighted HRVOC emissions. Application to the Houston plume indicates a HCHO source of 260±110 kmol h-1 and implies a factor of 5.5±2.4 underestimate of anthropogenic HRVOC emissions in the US Environmental Protection Agency inventory. This approach allows us to monitor trends in HRVOC emissions over the US, in particular from the urban areas and oil/gas industry.

  4. Anthropogenic Emissions of Highly Reactive Volatile Organic Compounds (HRVOCs) Inferred from Oversampling of OMI HCHO Columns

    NASA Technical Reports Server (NTRS)

    Zhu, Lei; Jacob, Daniel; Mickley, Loretta; Marais, Eloise; Zhang, Aoxing; Cohan, Daniel; Yoshida, Yasuko; Duncan, Bryan; Abad, Gonzalo Gonzalez; Chance, Kelly; DeSmedt, Isabelle

    2014-01-01

    Satellite observations of formaldehyde (HCHO) columns provide top-down constraints on emissions of highly reactive volatile organic compounds (HRVOCs). This approach has been used previously to constrain emissions of isoprene from vegetation, but application to US anthropogenic emissions has been stymied by lack of a discernable HCHO signal. Here we show that oversampling of HCHO data from the Ozone Monitoring Instrument (OMI) for 2005 - 2008 enables quantitative detection of urban and industrial plumes in eastern Texas including Houston, Port Arthur, and Dallas-Fort Worth. By spatially integrating the individual urban-industrial HCHO plumes observed by OMI we can constrain the corresponding HCHO-weighted HRVOC emissions. Application to the Houston plume indicates a HCHO source of 260 plus or minus 110 kmol h-1 and implies a factor of 5.5 plus or minus 2.4 underestimate of anthropogenic HRVOC emissions in the US Environmental Protection Agency inventory. With this approach we are able to monitor the trend in HRVOC emissions over the US, in particular from the oil-gas industry, over the past decade.

  5. A Highly Reactive Imidazolium-Bridged Dinucleotide Intermediate in Nonenzymatic RNA Primer Extension.

    PubMed

    Walton, Travis; Szostak, Jack W

    2016-09-14

    Because of its importance for the origin of life, the nonenzymatic copying of RNA templates has been the subject of intense study for several decades. Previous characterizations of template-directed primer extension using 5'-phosphoryl-2-methylimidazole-activated nucleotides (2-MeImpNs) as substrates have assumed a classical in-line nucleophilic substitution mechanism, in which the 3'-hydroxyl of the primer attacks the phosphate of the incoming monomer, displacing the 2-methylimidazole leaving group. However, we have found that the initial rate of primer extension depends on the pH and concentration at which the activated monomer is maintained prior to the primer extension reaction. These and other results suggest an alternative mechanism, in which two monomers react with each other to form an imidazolium-bridged dinucleotide intermediate, which then binds to the template. Subsequent attack of the 3'-hydroxyl of the primer displaces an activated nucleotide as the leaving group and results in extension of the primer by one nucleotide. Analysis of monomer solutions by NMR indicates formation of the proposed imidazolium-bridged dinucleotide in the expected pH-dependent manner. We have used synthetic methods to prepare material that is enriched in this proposed intermediate and show that it is a highly reactive substrate for primer extension. The formation of an imidazolium-bridged dinucleotide intermediate provides a mechanistic interpretation of previously observed catalysis by an activated nucleotide located downstream from the site of primer extension.

  6. Oxidative Reactivities of 2-Furylquinolines: Ubiquitous Scaffolds in Common High-Throughput Screening Libraries

    PubMed Central

    Olson, Margaret E.; Abate-Pella, Daniel; Perkins, Angela L.; Li, Ming; Carpenter, Michael A.; Rathore, Anurag; Harris, Reuben S.; Harki, Daniel A.

    2015-01-01

    High-throughput screening (HTS) was employed to discover APOBEC3G inhibitors and multiple 2-furylquinolines (e.g., 1) were found. Dose-response assays with 1 from the HTS sample, as well as commercial material, yielded similar confirmatory results. Interestingly, freshly synthesized and DMSO-solubilized 1 was inactive. Repeated screening of the DMSO aliquot of synthesized 1 revealed increasing APOBEC3G inhibitory activity with age, suggesting 1 decomposes into an active inhibitor. Laboratory aging of 1 followed by analysis revealed that 1 undergoes oxidative decomposition in air, resulting from a [4+2] cycloaddition between the furan of 1 and 1O2. The resulting endoperoxide then undergoes additional transformations, highlighted by Baeyer-Villager rearrangements, to deliver lactam, carboxylic acid, and aldehyde products. The endoperoxide also undergoes hydrolytic opening followed by further transformations to a bis-enone. Eight structurally related analogues from HTS libraries were similarly reactive. This study constitutes a cautionary to validate 2-furylquinolines for structure and stability prior to chemical optimization campaigns. PMID:26358009

  7. Perspective: Is there a hysteresis during reactive High Power Impulse Magnetron Sputtering (R-HiPIMS)?

    NASA Astrophysics Data System (ADS)

    Strijckmans, K.; Moens, F.; Depla, D.

    2017-02-01

    This paper discusses a few mechanisms that can assist to answer the title question. The initial approach is to use an established model for DC magnetron sputter deposition, i.e., RSD2013. Based on this model, the impact on the hysteresis behaviour of some typical HiPIMS conditions is investigated. From this first study, it becomes clear that the probability to observe hysteresis is much lower as compared to DC magnetron sputtering. The high current pulses cannot explain the hysteresis reduction. Total pressure and material choice make the abrupt changes less pronounced, but the implantation of ionized metal atoms that return to the target seems to be the major cause. To further substantiate these results, the analytical reactive sputtering model is coupled with a published global plasma model. The effect of metal ion implantation is confirmed. Another suggested mechanism, i.e., gas rarefaction, can be ruled out to explain the hysteresis reduction. But perhaps the major conclusion is that at present, there are too little experimental data available to make fully sound conclusions.

  8. Associations of High Sensitivity C-Reactive Protein Levels in Schizophrenia and Comparison Groups

    PubMed Central

    Joseph, Jamie; Depp, Colin; Martin, Averria Sirkin; Daly, Rebecca; Glorioso, Danielle K; Palmer, Barton W; Jeste, Dilip V

    2015-01-01

    Schizophrenia is characterized by physical (mainly metabolic and cardiovascular) comorbidity and shortened lifespan. High sensitivity C- reactive protein (hs-CRP), an inflammatory marker of hepatic origin linked to metabolic and cardiovascular diseases and mortality in the general population, has been reported to be elevated in people with schizophrenia. However, the relationship of hs-CRP to psychiatric and medical risk factors, after controlling for potentially confounding variables such as smoking, is not well established in schizophrenia. We assessed hs-CRP levels along with various demographic, psychiatric, and metabolic measures in 88 clinically stable outpatients with schizophrenia or schizoaffective disorder and 71 age epoch-matched comparison subjects with no history of a major psychiatric illness. hs-CRP levels were significantly higher in individuals with schizophrenia than in comparison subjects. Higher hs-CRP levels in schizophrenia group were associated with female gender, more severe negative symptoms, greater medical comorbidity, and worse metabolic risk factors including BMI, fasting glucose, and hemoglobin A1c levels. hs-CRP was not related to age, race, education, smoking status, antipsychotic dosage, or cognitive impairment. Longitudinal studies are needed to investigate the relationship between hs-CRP and long-term health outcomes including metabolic syndrome, cardiovascular disease, and mortality in schizophrenia. PMID:26341579

  9. Evidence for Different Reactive Hg Sources and Chemical Compounds at Adjacent Valley and High Elevation Locations.

    PubMed

    Sexauer Gustin, Mae; Pierce, Ashley M; Huang, Jiaoyan; Miller, Matthieu B; Holmes, Heather A; Loria-Salazar, S Marcela

    2016-11-15

    The spatial distribution of chemical compounds and concentration of reactive mercury (RM), defined as the sum of gaseous oxidized mercury (GOM) and <3 μm particulate bound mercury (PBM), are poorly characterized. The objective of this study was to understand the chemistry, concentration, and spatial and temporal distribution of GOM at adjacent locations (12 km apart) with a difference in elevation of ∼1000 m. Atmospheric GOM measurements were made with passive and active samplers using membranes, and at one location, a Tekran mercury measurement system was used. The chemistry of GOM varied across time and location. On the basis of data collected, chemistry at the low elevation site adjacent to a highway was primarily influenced by pollutants generated by mobile sources (GOM = nitrogen and sulfur-based compounds), and the high elevation site (GOM = halogen-based compounds) was affected by long-range transport in the free troposphere over the marine boundary layer into Nevada. Data collected at these two locations demonstrate that different GOM compounds exist depending on the oxidants present in the air. Measurements of GOM made by the KCl denuder in the Tekran instrument located at the low elevation site were lower than that measured using membranes by 1.7-13 times. Accurate measurements of atmospheric concentrations and chemistry of RM are necessary for proper assessment of environmental impacts, and field measurements are essential for atmospheric models, which in turn influence policy decisions.

  10. The Complementary Role of High Sensitivity C-Reactive Protein in the Diagnosis and Severity Assessment of Autism

    ERIC Educational Resources Information Center

    Khakzad, Mohammad Reza; Javanbakht, Maryam; Shayegan, Mohammad Reza; Kianoush, Sina; Omid, Fatemeh; Hojati, Maryam; Meshkat, Mojtaba

    2012-01-01

    C-reactive protein (CRP) is a beneficial diagnostic test for the evaluation of inflammatory response. Extremely low levels of CRP can be detected using high-sensitivity CRP (hs-CRP) test. A considerable body of evidence has demonstrated that inflammatory response has an important role in the pathophysiology of autism. In this study, we evaluated…

  11. Regulatory Behaviors and Stress Reactivity among Infants at High Risk for Fetal Alcohol Spectrum Disorders: An Exploratory Study

    ERIC Educational Resources Information Center

    Jirikowic, Tracy; Chen, Maida; Nash, Jennifer; Gendler, Beth; Olson, Heather Carmichael

    2016-01-01

    Introduction: This article examines regulatory behaviors and physiological stress reactivity among 6-15 month-old infants with moderate to heavy prenatal alcohol exposure (PAE), a group at very high risk for fetal alcohol spectrum disorders and self-regulation impairments, compared to low risk infants with no/low exposure. Participants: Eighteen…

  12. 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

  13. Soot Structure and Reactivity Analysis by Raman Microspectroscopy, Temperature-Programmed Oxidation, and High-Resolution Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Knauer, Markus; Schuster, Manfred E.; Su, Dangsheng; Schlögl, Robert; Niessner, Reinhard; Ivleva, Natalia P.

    2009-11-01

    Raman microspectroscopy (RM), temperature-programmed oxidation (TPO), high-resolution transmission electron microscopy (HRTEM), and electron energy loss spectroscopy (EELS) were combined to get comprehensive information on the relationship between structure and reactivity of soot in samples of spark discharge (GfG), heavy duty engine diesel (EURO VI and IV) soot, and graphite powder upon oxidation by oxygen at increasing temperatures. GfG soot and graphite powder represent the higher and lower reactivity limits. Raman microspectroscopic analysis was conducted by determination of spectral parameters using a five band fitting procedure (G, D1-D4) as well as by evaluation of the dispersive character of the D mode. The analysis of spectral parameters shows a higher degree of disorder and a higher amount of molecular carbon for untreated GfG soot samples than for samples of untreated EURO VI and EURO IV soot. The structural analysis based on the dispersive character of the D mode revealed substantial differences in ordering descending from graphite powder, EURO IV, VI to GfG soot. HRTEM images and EELS analysis of EURO IV and VI samples indicated a different morphology and a higher structural order as compared to GfG soot in full agreement with the Raman analysis. These findings are also confirmed by the reactivity of soot during oxidation (TPO), where GfG soot was found to be the most reactive and EURO IV and VI soot samples exhibited a moderate reactivity.

  14. Peptide reactivity assay using spectrophotometric method for high-throughput screening of skin sensitization potential of chemical haptens.

    PubMed

    Jeong, Yun Hyeok; An, Susun; Shin, Kyeho; Lee, Tae Ryong

    2013-02-01

    Haptens must react with cellular proteins to be recognized by antigen presenting cells. Therefore, monitoring reactivity of chemicals with peptide/protein has been considered an in vitro skin sensitization testing method. The reactivity of peptides with chemicals (peptide reactivity) has usually been monitored by chromatographic methods like HPLC or LC/MS, which are robust tools for monitoring common chemical reactions but are rather expensive and time consuming. Here, we examined the possibility of using spectrophotometric methods to monitor peptide reactivity. Two synthetic peptides, Ac-RWAACAA and Ac-RWAAKAA, were reacted with 48 chemicals (34 sensitizers and 14 non-sensitizers). Peptide reactivity was measured by monitoring unreacted peptides with UV-Vis spectrophotometer using 5,5'-dithiobis-2-nitrobenzoic acid as a detection reagent for the free thiol group of cysteine-containing peptide or fluorometer using fluorescamine™ as a detection reagent for the free amine group of lysine-containing peptide. Chemicals were categorized as sensitizers when they induced more than 10% depletion of cysteine-containing peptide or 20% depletion of lysine-containing peptide. The sensitivity, specificity, and accuracy of this method were 82.4%, 85.7%, and 83.3%, respectively. These results demonstrate that spectrophotometric methods can be easy, fast, and high-throughput screening tools for the prediction of the skin sensitization potential of chemical haptens.

  15. 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.

  16. Reactive trace element enrichment in a highly modified, tidally inundated acid sulfate soil wetland: East Trinity, Australia.

    PubMed

    Keene, Annabelle F; Johnston, Scott G; Bush, Richard T; Burton, Edward D; Sullivan, Leigh A

    2010-04-01

    This study examines the abundance of trace elements in surface sediments of a former acid sulfate soil (ASS) wetland subjected to marine tidal inundation. Sediment properties of this highly modified study site are compared with those of an adjacent unmodified, intertidal mangrove forest. Whilst some trace elements (Al, Cd, Mn, Ni and Zn) were clearly depleted due to mobilisation and leaching in the previous oxic-acidic phase, other trace elements (As and Cr) displayed significant enrichment in the tidally inundated ASS. Many trace elements were strongly associated with the reactive Fe and acid volatile sulfide (AVS) fractions, suggesting that trace elements may be adsorbed to abundant reactive Fe phases or sequestered as sulfide minerals. These findings provide an important understanding of the fate and mobility of reactive iron, AVS and trace elements during tidal remediation of a formerly acidified Great Barrier Reef (GBR) catchment.

  17. Reactive sintering and reactive hot

    NASA Astrophysics Data System (ADS)

    Murray, J. C.; German, R. M.

    1992-09-01

    NbAl3 has been synthesized from elemental powders by reactive sintering (RS) and reactive hot isostatic pressing (RHIP). Both processes involve a self-propagating exothermic reaction between the constituent powders to form an intermetallic compound. The RHIP approach uses simultaneous external pressurization to make a higher density product. This study focused on developing a method to use reactive synthesis to form high-density NbAl3 compacts. High RS and RHIP densities were possible with the appropriate raw materials and processing parameters. These include powder purity, particle sizes, degassing, heating rate, furnace temperature, and compaction pressures. Near full density was attained with RHIP, and up to 95 pct density was attained with RS.

  18. Surface Enhanced Raman Spectroscopy on Carbonate Fluids at High Pressures: A New Technique to Study Fluid Species Under Geologically Relevant Conditions

    NASA Astrophysics Data System (ADS)

    Chopelas, A.; Black, J. R.; Kavner, A.; Manning, C. E.

    2010-12-01

    The physical and chemical behavior of fluid/mineral interfaces at high pressures and temperatures help govern the generation of magmas, the evolution of the continental crust, and the storage and cycling of volatiles such as water and carbon in and through the Earth’s crust and mantle reservoirs. Little is known of the speciation of silica- and oxidized carbon- bearing fluids at relevant conditions of pressure, temperature and concentration. Currently, our high pressure P/high temperature T Raman spectroscopy studies in the hydrothermal DAC have yielded promising insights into P,T dependence of carbon/bicarbonate speciation. However, due to the low intensity of Raman scattering, results can only be obtained on fluids with carbon species concentrations that are unreasonably high compared with actual geological fluids. To help examine the chemistry of geological fluids at relevant concentrations and P-T conditions, we are developing a technique known as Surface Enhanced Raman Spectroscopy (SERS) in the hydrothermal diamond anvil cell. SERS is a resonant Raman phenomenon yielding potentially large enhancements in spectroscopic signal for Raman-active species adsorbed on nano-structured metals. Currently, this technique is widely used in the chemistry community, and has been mostly been devoted to studying organic materials, including proteins, aromatics, etc, and fluid-nanoparticle interactions. Enhancements in Raman signal of a few orders of magnitude are typical. Here, we show our SERS results on dilute carbonate/bicarbonate solutions at ambient conditions, and at high pressures in the diamond anvil cell. We obtained ambient pressure SERS signal for a dilute 0.02 M bicarbonate/carbonate fluid, using Au, Ag, and Cu as nanoparticle substrates. In the diamond cell, we obtained SERS spectra on a ~0.1 M bicarbonate solution at pressures ranging from 1 GPa to 3 GPa. The SERS spectra revealed the same sequence carbonate/bicarbonate transformations we observed at higher

  19. Synthesis of Self-Assembled Multifunctional Nanocomposite Catalysts with Highly Stabilized Reactivity and Magnetic Recyclability

    NASA Astrophysics Data System (ADS)

    Yu, Xu; Cheng, Gong; Zheng, Si-Yang

    2016-05-01

    In this paper, a multifunctional Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite catalyst with highly stabilized reactivity and magnetic recyclability was synthesized by a self-assembled method. The magnetic Fe3O4 nanoparticles were coated with a thin layer of the SiO2 to obtain a negatively charged surface. Then positively charged poly(ethyleneimine) polymer (PEI) was self-assembled onto the Fe3O4@SiO2 by electrostatic interaction. Next, negatively charged glutathione capped gold nanoparticles (GSH-AuNPs) were electrostatically self-assembled onto the Fe3O4@SiO2@PEI. After that, silver was grown on the surface of the nanocomposite due to the reduction of the dopamine in the alkaline solution. An about 5 nm thick layer of polydopamine (PDA) was observed to form the Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was carefully characterized by the SEM, TEM, FT-IR, XRD and so on. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite shows a high saturation magnetization (Ms) of 48.9 emu/g, which allows it to be attracted rapidly to a magnet. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was used to catalyze the reduction of p-nitrophenol (4-NP) to p-aminophenol (4-AP) as a model system. The reaction kinetic constant k was measured to be about 0.56 min‑1 (R2 = 0.974). Furthermore, the as-prepared catalyst can be easily recovered and reused for 8 times, which didn’t show much decrease of the catalytic capability.

  20. Influence of age on reactivity to diverse emotional challenges in low- and high-anxiety rats.

    PubMed

    de Oliveira, Luciana C; Gomes, Margareth Z; Brandão, Marcus L

    2011-02-01

    Studies have revealed that the extent of reactivity of high-anxiety rats to diverse challenges is different than low-anxiety rats and have provided important insights into the psychopathology of anxiety. Various factors intervene to allow defensive mechanisms to react to diverse threatening challenges, including ontogeny and the nature of the emotional challenge (e.g., conditioned vs. unconditioned). The present study investigated the extent to which a particular type of fear extrapolates to other emotional responses to diverse threatening challenges. Groups of 30- and 60-day-old rats were assigned to low freezing behavior (LFB) and high freezing behavior (HFB) groups using the contextual fear conditioning paradigm and subjected to either the fear-potentiated startle (FPS) test, novelty-induced ultrasound vocalizations (USVs) or elevated plus-maze (EPM) tests. At 30 days of age, HFB rats exhibited greater FPS than LFB rats. In contrast, prior selection of HFB and LFB did not affect the performance of 30-day-old animals in the EPM and novelty-induced USVs. Sixty-day-old animals exhibited a performance deficit in all three tests. These data suggest that the performance of young rats in animal models of anxiety parallels their selection as LFB and HFB in the contextual fear conditioning paradigm. However, the increased fear-like behavior exhibited by the 60-day-old HFB rats may elicit performance deficits in conditioned and unconditioned fear tests. These results suggest that the interaction between hyperanxiety and age may cause a performance deficit despite the animals' increased fear-like behavior when facing emotional challenges, thus resembling psychiatric patients in many respects.

  1. Synthesis of Self-Assembled Multifunctional Nanocomposite Catalysts with Highly Stabilized Reactivity and Magnetic Recyclability

    PubMed Central

    Yu, Xu; Cheng, Gong; Zheng, Si-Yang

    2016-01-01

    In this paper, a multifunctional Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite catalyst with highly stabilized reactivity and magnetic recyclability was synthesized by a self-assembled method. The magnetic Fe3O4 nanoparticles were coated with a thin layer of the SiO2 to obtain a negatively charged surface. Then positively charged poly(ethyleneimine) polymer (PEI) was self-assembled onto the Fe3O4@SiO2 by electrostatic interaction. Next, negatively charged glutathione capped gold nanoparticles (GSH-AuNPs) were electrostatically self-assembled onto the Fe3O4@SiO2@PEI. After that, silver was grown on the surface of the nanocomposite due to the reduction of the dopamine in the alkaline solution. An about 5 nm thick layer of polydopamine (PDA) was observed to form the Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was carefully characterized by the SEM, TEM, FT-IR, XRD and so on. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite shows a high saturation magnetization (Ms) of 48.9 emu/g, which allows it to be attracted rapidly to a magnet. The Fe3O4@SiO2@PEI-Au/Ag@PDA nanocomposite was used to catalyze the reduction of p-nitrophenol (4-NP) to p-aminophenol (4-AP) as a model system. The reaction kinetic constant k was measured to be about 0.56 min−1 (R2 = 0.974). Furthermore, the as-prepared catalyst can be easily recovered and reused for 8 times, which didn’t show much decrease of the catalytic capability. PMID:27147586

  2. High Temperature Hydrothermal Circulation in the Deep Oceanic Crust - Sr Isotopes and Trace Elements Modelisation Constraints on the Origin of the Fluids

    NASA Astrophysics Data System (ADS)

    Bosch, D.; Lamour, M.; Jamais, M.; Bodinier, J.

    2003-12-01

    Previous field, petrological and geochemical works have identified high temperature hydrous alteration traces throughout the gabbros of the Samail ophiolite. Temperatures have been calibrated for the successive stages of alteration, starting with orthopyroxene-pargasite coronas (above 975 \\deg C) and ending with the low temperature (LT) lizardite serpentinisation (below 500 \\deg C). Sr isotopic analyses performed on massive gabbros, dikes and veins and associated minerals depart from typical mantle signatures and are characterized by radiogenic Sr isotopic ratios suggesting seawater as the most likely hydrothermal contaminant. The main water channels may be submillimetric microcracks with a dominantly vertical attitude and constituting the recharge hydrothermal system, whereas dikes and veins represent the discharge part. This model requires that these dikes have been generated by hydration of the crystallizing gabbros via seawater penetration, near the internal wall of the LVZ-magma chamber, i.e. at temperatures well above the near 1000 \\deg C temperature recorded so far. We used the numerical plate model of VerniŠres et al. (1997) to simulate the chemical evolution of Sr isotopes and some trace elements in fluids through the gabbro column. This approach takes into account mineralogical and porosity variations due to dissolution-precipitation processes, as well as variations of partition coefficients as a function of distance from the fluid source. The aim of modelling was twofold: (1) to provide estimates of the chemical evolution of fluids as a result of high-temperature interaction with gabbros, and (2) to constrain the fluid-rock ratios throughout the gabbros sequence. Such an approach sheds new lights on the importance of high temperature hydrothermal processes and on the geochemical modifications they induced during oceanic crust formation at fast spreading ridge. VerniŠres J., Godard M., Bodinier J.-L., 1997. A plate model for the simulation of trace

  3. High order numerical simulations of the Richtmyer- Meshkov instability in a relativistic fluid

    NASA Astrophysics Data System (ADS)

    Zanotti, O.; Dumbser, M.

    2015-07-01

    We study the Richtmyer-Meshkov (RM) instability of a relativistic perfect fluid by means of high order numerical simulations with adaptive mesh refinement (AMR). The numerical scheme combines a finite volume reconstruction in space, a local space-time discontinuous Galerkin predictor method, a high order one-step time update scheme, and a "cell-by-cell" space-time AMR strategy with time-accurate local time stepping. In this way, third order accurate (both in space and in time) numerical simulations of the RM instability are performed, spanning a wide parameter space. We present results both for the case in which a light fluid penetrates into a higher density one (Atwood number A > 0) and for the case in which a heavy fluid penetrates into a lower density one (Atwood number A < 0). We find that for large Lorentz factors γs of the incident shock wave, the relativistic RM instability is substantially weakened and ultimately suppressed. More specifically, the growth rate of the RM instability in the linear phase has a local maximum which occurs at a critical value of γs ≈ [1.2, 2]. Moreover, we have also revealed a genuinely relativistic effect, absent in Newtonian hydrodynamics, which arises in three dimensional configurations with a non-zero velocity component tangent to the incident shock front. In particular, in A > 0 models, the tangential velocity has a net magnification effect, while in A < 0 models, the tangential velocity has a net suppression effect.

  4. 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.

  5. On equivalence of high temperature series expansion and coupling parameter series expansion in thermodynamic perturbation theory of fluids

    SciTech Connect

    Sai Venkata Ramana, A.

    2014-04-21

    The coupling parameter series expansion and the high temperature series expansion in the thermodynamic perturbation theory of fluids are shown to be equivalent if the interaction potential is pairwise additive. As a consequence, for the class of fluids with the potential having a hardcore repulsion, if the hard-sphere fluid is chosen as reference system, the terms of coupling parameter series expansion for radial distribution function, direct correlation function, and Helmholtz free energy follow a scaling law with temperature. The scaling law is confirmed by application to square-well fluids.

  6. Highly responsive core-shell microactuator arrays for use in viscous and viscoelastic fluids

    PubMed Central

    Fiser, Briana L.; Shields, Adam R.; Falvo, M. R.; Superfine, R.

    2015-01-01

    We present a new fabrication method to produce arrays of highly responsive polymer-metal core-shell magnetic microactuators. The core-shell fabrication method decouples the elastic and magnetic structural components such that the actuator response can be optimized by adjusting the core-shell geometry. Our microstructures are 10 μm long, 550 nm in diameter, and electrochemically fabricated in particle track-etched membranes, comprising a poly(dimethylsiloxane) core with a 100 nm Ni shell surrounding the upper 3–8 μm. The structures can achieve deflections of nearly 90° with moderate magnetic fields and are capable of driving fluid flow in a fluid 550 times more viscous than water. PMID:26405376

  7. 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

  8. Practical development of continuous supercritical fluid process using high pressure and high temperature micromixer

    NASA Astrophysics Data System (ADS)

    Kawasaki, Shin-Ichiro; Sue, Kiwamu; Ookawara, Ryuto; Wakashima, Yuichiro; Suzuki, Akira

    2015-12-01

    In the synthesis of metal oxide fine particles by continuous supercritical hydrothermal method, the particle characteristics are greatly affected by not only the reaction conditions (temperature, pressure, residence time, concentration, etc.), but also the heating rate from ambient to reaction temperature. Therefore, the heating method by direct mixing of starting solution at room temperature with supercritical water is a key technology for the particle production having smaller size and narrow distribution. In this paper, mixing engineering study through comparison between conventional T-shaped mixers and recently developed swirl mixers was carried out in the hydrothermal synthesis of NiO nanoparticles from Ni(NO3)2 aqueous solution at 400 °C and 30 MPa. Inner diameter in the mixers and total flow rates were varied. Furthermore, the heating rate was calculated by computational fluid dynamics (CFD) simulation. Relationship between the heating rate and the average particle size were discussed. It was clarified that the miniaturization of mixer inner diameter and the use of the swirl flow were effective for improving mixing performance and contributed to produce small and narrow distribution particle under same experimental condition of flow rate, temperature, pressure, residence time, and concentration of the starting materials. We have focused the mixer optimization due to a difference in fluid viscosity.

  9. A perspective on high-order methods in computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Wang, ZhiJian

    2016-01-01

    There has been an intensive international effort to develop high-order Computational Fluid Dynamics (CFD) methods into design tools in aerospace engineering during the last one and half decades. These methods offer the potential to significantly improve solution accuracy and efficiency for vortex dominated turbulent flows. Enough progresses have been made in algorithm development, mesh generation and parallel computing that these methods are on the verge of being applied in a production design environment. Since many review papers have been written on the subject, I decide to offer a personal perspective on the state-of-the-art in high-order CFD methods and the challenges that must be overcome.

  10. A high-order Immersed Boundary method for solving fluid problems on arbitrary smooth domains

    NASA Astrophysics Data System (ADS)

    Stein, David; Guy, Robert; Thomases, Becca

    2015-11-01

    We present a robust, flexible, and high-order Immersed Boundary method for solving the equations of fluid motion on domains with smooth boundaries using FFT-based spectral methods. The solution to the PDE is coupled with an equation for a smooth extension of the unknown solution; high-order accuracy is a natural consequence of this additional global regularity. The method retains much of the simplicity of the original Immersed Boundary method, and enables the use of simple implicit and implicit/explicit timestepping schemes to be used to solve a wide range of problems. We show results for the Stokes, Navier-Stokes, and Oldroyd-B equations.

  11. 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

  12. A Manganese Catalyst for Highly Reactive Yet Chemoselective Intramolecular C(sp3)—H Amination

    PubMed Central

    Paradine, Shauna M.; Griffin, Jennifer R.; Zhao, Jinpeng; Petronico, Aaron L.; Miller, Shannon M.; White, M. Christina

    2016-01-01

    C—H bond oxidation reactions underscore the existing paradigm wherein high reactivity and high selectivity are inversely correlated. The development of catalysts capable of oxidizing strong aliphatic C(sp3)—H bonds while displaying chemoselectivity (i.e. tolerance of more oxidizable functionality) remains an unsolved problem. Herein, we describe a catalyst, manganese tert-butylphthalocyanine [Mn(tBuPc)], that is an outlier to the reactivity-selectivity paradigm. It is unique in its capacity to functionalize all types of C(sp3)—H bonds intramolecularly, while displaying excellent chemoselectivity in the presence of π-functionality. Mechanistic studies indicate that [Mn(tBuPc)] transfers bound nitrenes to C(sp3)—H bonds via a pathway that lies between concerted C—H insertion, observed with reactive noble metals (e.g. rhodium), and stepwise radical C—H abstraction/rebound, observed with chemoselective base metals (e.g. iron). Rather than achieving a blending of effects, [Mn(tBuPc)] aminates even 1° aliphatic and propargylic C—H bonds, reactivity and selectivity unusual for previously known catalysts. PMID:26587714

  13. Remarkably high activities of testicular cytochrome c in destroying reactive oxygen species and in triggering apoptosis

    PubMed Central

    Liu, Zhe; Lin, Hao; Ye, Sheng; Liu, Qin-ying; Meng, Zhaohui; Zhang, Chuan-mao; Xia, Yongjing; Margoliash, Emanuel; Rao, Zihe; Liu, Xiang-jun

    2006-01-01

    Hydrogen peroxide (H2O2) is the major reactive oxygen species (ROS) produced in sperm. High concentrations of H2O2 in sperm induce nuclear DNA fragmentation and lipid peroxidation and result in cell death. The respiratory chain of the mitochondrion is one of the most productive ROS generating systems in sperm, and thus the destruction of ROS in mitochondria is critical for the cell. It was recently reported that H2O2 generated by the respiratory chain of the mitochondrion can be efficiently destroyed by the cytochrome c-mediated electron-leak pathway where the electron of ferrocytochrome c migrates directly to H2O2 instead of to cytochrome c oxidase. In our studies, we found that mouse testis-specific cytochrome c (T-Cc) can catalyze the reduction of H2O2 three times faster than its counterpart in somatic cells (S-Cc) and that the T-Cc heme has the greater resistance to being degraded by H2O2. Together, these findings strongly imply that T-Cc can protect sperm from the damages caused by H2O2. Moreover, the apoptotic activity of T-Cc is three to five times greater than that of S-Cc in a well established apoptosis measurement system using Xenopus egg extract. The dramatically stronger apoptotic activity of T-Cc might be important for the suicide of male germ cells, considered a physiological mechanism that regulates the number of sperm produced and eliminates those with damaged DNA. Thus, it is very likely that T-Cc has evolved to guarantee the biological integrity of sperm produced in mammalian testis. PMID:16757556

  14. High-sensitivity C-reactive protein in paediatric inflammatory bowel disease

    PubMed Central

    Sidoroff, Marianne; Karikoski, Riitta; Raivio, Taneli; Savilahti, Erkki; Kolho, Kaija-Leena

    2010-01-01

    AIM: To study whether high-sensitivity C-reactive protein (hs-CRP) measurement can aid the assessment of disease activity and glucocorticoid treatment in paediatric inflammatory bowel disease (IBD). METHODS: CRP levels were measured in 39 children with IBD undergoing colonoscopy [median age 12.8 years, Crohn’s disease (CD) n = 20], in 22 other children with IBD followed for acute response to glucocorticoids, and in 33 paediatric non-IBD patients. When standard CRP level was below detection limit (< 5 mg/L), hs-CRP was analyzed. RESULTS: Sixty-four percent (25/39) of the children with IBD undergoing colonoscopy displayed undetectable (< 5 mg/L) standard CRP levels. Of these, the hs-CRP measurement could not differentiate between active (median, 0.2 mg/L, range, 0.007-1.37, n = 17) or quiescent (0.1 mg/L, 0.01-1.89, n = 8, P = NS) disease. Patients with ileocolonic CD had higher CRP levels (14 mg/L, 0.06-45, n = 13) than patients with no ileal involvement (0.18 mg/L, 0.01-9, n = 7, P < 0.01) or ulcerative colitis (UC) (0.13 mg/L, 0.007-23, P < 0.05). In children with active IBD treated with systemic glucocorticoids, the standard CRP was undetectable in 59% of the patients. The hs-CRP levels did not differ between patients that responded to steroid therapy and in non-responders. CONCLUSION: The measurement of hs-CRP did not prove useful in the assessment of disease activity or glucocorticoid treatment in paediatric IBD patients that had undetectable standard CRP. PMID:20556836

  15. Impact of fluorine based reactive chemistry on structure and properties of high moment magnetic material

    SciTech Connect

    Yang, Xiaoyu Chen, Lifan; Han, Hongmei; Fu, Lianfeng; Sun, Ming; Liu, Feng; Zhang, Jinqiu

    2014-05-07

    The impact of the fluorine-based reactive ion etch (RIE) process on the structural, electrical, and magnetic properties of NiFe and CoNiFe-plated materials was investigated. Several techniques, including X-ray fluorescence, 4-point-probe, BH looper, transmission electron microscopy (TEM), and electron energy loss spectroscopy (EELS), were utilized to characterize both bulk film properties such as thickness, average composition, Rs, ρ, Bs, Ms, and surface magnetic “dead” layers' properties such as thickness and element concentration. Experimental data showed that the majority of Rs and Bs changes of these bulk films were due to thickness reduction during exposure to the RIE process. ρ and Ms change after taking thickness reduction into account were negligible. The composition of the bulk films, which were not sensitive to surface magnetic dead layers with nano-meter scale, showed minimum change as well. It was found by TEM and EELS analysis that although both before and after RIE there were magnetic dead layers on the top surface of these materials, the thickness and element concentration of the layers were quite different. Prior to RIE, dead layer was actually native oxidation layers (about 2 nm thick), while after RIE dead layer consisted of two sub-layers that were about 6 nm thick in total. Sub-layer on the top was native oxidation layer, while the bottom layer was RIE “damaged” layer with very high fluorine concentration. Two in-situ RIE approaches were also proposed and tested to remove such damaged sub-layers.

  16. Flow and Geometry Control the Onset of Jamming in Fractures with High Solid-Fraction Fluids

    NASA Astrophysics Data System (ADS)

    Medina, R.; Elkhoury, J. E.; Shannon, L. J.; Detwiler, R. L.; Morris, J.; Prioul, R.; Desroches, J.

    2013-12-01

    Fluids containing a large fraction of suspended solids are common in the subsurface. Examples include fluids used for environmental remediation, hydraulic fracturing fluids and magma. These fluid-solid mixtures behave as non-Newtonian fluids where interactions between fluid, suspended solids, and pore walls can lead to jamming of the suspended solids. Jamming causes the velocity of the solid to decrease locally to zero causing a rapid decrease in permeability as the fluid is forced to flow through the pore space within the immobilized solid. Here we present results from experiments that quantify the flow of non-Newtonian suspensions in an analog parallel-plate fracture (transparent 15cm x 15cm with ~3-mm aperture) and explore the dependence of jamming on flow conditions, fracture geometry, and the action of gravity. We used guar gum mixed with water (0.75%) as the fluid and added 50% by volume of crushed silica (< 300μm). Flow rates ranged from 0.2ml/min to 6.0ml/min, cell orientation varied from horizontal to vertical (bottom to top) flow and a transducer provided continuous measurement of differential pressure across the cell. A strobed LED panel backlit the cell and a high-resolution CCD camera captured frequent (0.2 Hz) images during all experiments. Particle image velocimetry (PIV) yielded measurements of the evolving velocity field during experiments (see Figure). In the vertical orientation during the initial period of high flow rate, outflow decreased rapidly and the differential pressure increased indicating jamming within the cell. Subsequent efforts to flush solids from the cell suggested that jamming occurred at the inlet of the cell. This was likely due to settling of solids within the flow field indicating that the time scale associated with settling was shorter than the time scale of advection through the cell. In the horizontal orientation, localized jamming occurred at the lowest flow rate in a region near the outlet. This suggests that when

  17. Chemical reactivity of CVC and CVD SiC with UO2 at high temperatures

    NASA Astrophysics Data System (ADS)

    Silva, Chinthaka M.; Katoh, Yutai; Voit, Stewart L.; Snead, Lance L.

    2015-05-01

    Two types of silicon carbide (SiC) synthesized using two different vapor deposition processes were embedded in UO2 pellets and evaluated for their potential chemical reaction with UO2. While minor reactivity between chemical-vapor-composited (CVC) SiC and UO2 was observed at comparatively low temperatures of 1100 and 1300 °C, chemical-vapor-deposited (CVD) SiC did not show any such reactivity. However, both CVD and CVC SiCs showed some reaction with UO2 at a higher temperature (1500 °C). Elemental maps supported by phase maps obtained using electron backscatter diffraction indicated that CVC SiC was more reactive than CVD SiC at 1500 °C. Furthermore, this investigation indicated the formation of uranium carbides and uranium silicide chemical phases such as UC, USi2, and U3Si2 as a result of SiC reaction with UO2.

  18. High precision Hugoniot measurements on statically pre-compressed fluid helium

    SciTech Connect

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

    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 modest (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 (up) relationship: us = C0 + sup, with C0 = 1.44 ± 0.14 km/s and s = 1.344 ± 0.025.

  19. 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

  20. Explicit high-order noncanonical symplectic algorithms for ideal two-fluid systems

    NASA Astrophysics Data System (ADS)

    Xiao, Jianyuan; Qin, Hong; Morrison, Philip J.; Liu, Jian; Yu, Zhi; Zhang, Ruili; He, Yang

    2016-11-01

    An explicit high-order noncanonical symplectic algorithm for ideal two-fluid systems is developed. The fluid is discretized as particles in the Lagrangian description, while the electromagnetic fields and internal energy are treated as discrete differential form fields on a fixed mesh. With the assistance of Whitney interpolating forms [H. Whitney, Geometric Integration Theory (Princeton University Press, 1957); M. Desbrun et al., Discrete Differential Geometry (Springer, 2008); J. Xiao et al., Phys. Plasmas 22, 112504 (2015)], this scheme preserves the gauge symmetry of the electromagnetic field, and the pressure field is naturally derived from the discrete internal energy. The whole system is solved using the Hamiltonian splitting method discovered by He et al. [Phys. Plasmas 22, 124503 (2015)], which was been successfully adopted in constructing symplectic particle-in-cell schemes [J. Xiao et al., Phys. Plasmas 22, 112504 (2015)]. Because of its structure preserving and explicit nature, this algorithm is especially suitable for large-scale simulations for physics problems that are multi-scale and require long-term fidelity and accuracy. The algorithm is verified via two tests: studies of the dispersion relation of waves in a two-fluid plasma system and the oscillating two-stream instability.

  1. 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 (up) relationship: us = C0 + sup, with C0 = 1.44 ± 0.14 km/s and s = 1.344 ± 0.025.« less

  2. 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.

  3. Effect of environment on iodine oxidation state and reactivity with aluminum.

    PubMed

    Smith, Dylan K; McCollum, Jena; Pantoya, Michelle L

    2016-04-28

    Iodine oxide is a highly reactive solid oxidizer and with its abundant generation of iodine gas during reaction, this oxidizer also shows great potential as a biocidal agent. A problem with using I2O5 in an energetic mixture is its highly variable reactive behavior. This study isolates the variable reactivity associated with I2O5 as a function of its chemical reaction in various environments. Specifically, aluminum fuel and iodine oxide powder are combined using a carrier fluid to aid intermixing. The carrier fluid is shown to significantly affect the oxidation state of iodine oxide, thereby affecting the reactivity of the mixture. Four carrier fluids were investigated ranging in polarity and water miscibility in increasing order from hexane < acetone < isopropanol < water as well as untreated, dry-mixed reactants. Oxidation state and reactivity were examined with experimental techniques including X-ray photoelectric spectroscopy (XPS) and differential scanning calorimetry (DSC). Results are compared with thermal equilibrium simulations. Flame speeds increased with polarity of the fluid used to intermix the powder and ranged from 180 to 1202 m s(-1). The I2O5 processed in the polar fluids formed hydrated states of iodine oxide: HIO3 and HI3O8; and, the nonpolar and dry-mixed samples formed: I2O4 and I4O9. During combustion, the hydrated iodine oxides rapidly dehydrated from HIO3 to HI3O8 and from HI3O8 to I2O5. Both steps release 25% of their mass as vapor during combustion. Increased gas generation enhances convective energy transport and accounts for the increase in reactivity seen in the mixtures processed in polar fluids. These results explain the chemical mechanisms underlying the variable reactivity of I2O5 that are a function of the oxide's highly reactive nature with its surrounding environment. These results will significantly impact the selection of carrier fluid in the synthesis approach for iodine containing reactive mixtures.

  4. Nanopore reactive adsorbents for the high-efficiency removal of waste species

    DOEpatents

    Yang, Arthur Jing-Min; Zhang, Yuehua

    2005-01-04

    A nanoporous reactive adsorbent incorporates a relatively small number of relatively larger reactant, e.g., metal, enzyme, etc., particles (10) forming a discontinuous or continuous phase interspersed among and surrounded by a continuous phase of smaller adsorbent particles (12) and connected interstitial pores (14) therebetween. The reactive adsorbent can effectively remove inorganic or organic impurities in a liquid by causing the liquid to flow through the adsorbent. For example, silver ions may be adsorbed by the adsorbent particles (12) and reduced to metallic silver by reducing metal, such as ions, as the reactant particles (10). The column can be regenerated by backwashing with the liquid effluent containing, for example, acetic acid.

  5. Euphorbia Kansui Reactivates Latent HIV

    PubMed Central

    Cary, Daniele C.; Fujinaga, Koh; Peterlin, B. Matija

    2016-01-01

    While highly active anti-retroviral therapy has greatly improved the lives of HIV infected individuals, these treatments are unable to eradicate the virus. Current approaches to reactivate the virus have been limited by toxicity, lack of an orally available therapy, and limited responses in primary CD4+ T cells and in clinical trials. The PKC agonist ingenol, purified from Euphorbia plants, is a potent T cell activator and reactivates latent HIV. Euphorbia kansui itself has been used for centuries in traditional Chinese medicine to treat ascites, fluid retention, and cancer. We demonstrate that an extract of this plant, Euphorbia kansui, is capable of recapitulating T cell activation induced by the purified ingenol. Indeed, Euphorbia kansui induced expression of the early T cell activation marker CD69 and P-TEFb in a dose-dependent manner. Furthermore, Euphorbia kansui reactivated latent HIV in a CD4+ T cell model of latency and in HIV+ HAART suppressed PBMC. When combined with the other latency reversing agents, the effective dose of Euphorbia kansui required to reactive HIV was reduced 10-fold and resulted in synergistic reactivation of latent HIV. We conclude that Euphorbia Euphorbia kansui reactivates latent HIV and activates CD4+ T cells. When used in combination with a latency reversing agent, the effective dose of Euphorbia kansui is reduced; which suggests its application as a combination strategy to reactivate latent HIV while limiting the toxicity due to global T cell activation. As a natural product, which has been used in traditional medicine for thousands of years, Euphorbia kansui is attractive as a potential treatment strategy, particularly in resource poor countries with limited treatment options. Further clinical testing will be required to determine its safety with current anti-retroviral therapies. PMID:27977742

  6. Gaseous bubble oscillations in anisotropic non-Newtonian fluids under influence of high-frequency acoustic field

    NASA Astrophysics Data System (ADS)

    Golykh, R. N.

    2016-06-01

    Progress of technology and medicine dictates the ever-increasing requirements (heat resistance, corrosion resistance, strength properties, impregnating ability, etc.) for non-Newtonian fluids and materials produced on their basis (epoxy resin, coating materials, liquid crystals, etc.). Materials with improved properties obtaining is possible by modification of their physicochemical structure. One of the most promising approaches to the restructuring of non-Newtonian fluids is cavitation generated by high-frequency acoustic vibrations. The efficiency of cavitation in non-Newtonian fluid is determined by dynamics of gaseous bubble. Today, bubble dynamics in isotropic non-Newtonian fluids, in which cavitation bubble shape remains spherical, is most full investigated, because the problem reduces to ordinary differential equation for spherical bubble radius. However, gaseous bubble in anisotropic fluids which are most wide kind of non-Newtonian fluids (due to orientation of macromolecules) deviates from spherical shape due to viscosity dependence on shear rate direction. Therefore, the paper presents the mathematical model of gaseous bubble dynamics in anisotropic non-Newtonian fluids. The model is based on general equations for anisotropic non-Newtonian fluid flow. The equations are solved by asymptotic decomposition of fluid flow parameters. It allowed evaluating bubble size and shape evolution depending on rheological properties of liquid and acoustic field characteristics.

  7. The Role of Reactivation and Fluid Pressure Cycling in The Development of Late Zeolite-bearing Faults and Fractures From The Adamello Batholith, Italy

    NASA Astrophysics Data System (ADS)

    Dempsey, E. D.; Holdsworth, R. E.; Di Toro, G.

    2011-12-01

    Interconnected networks of faults and veins filled with zeolites and other minerals are a common feature of many crystalline rocks, including basaltic volcanics, deformed granitic plutons and regions of high grade continental basement. Typically the fracture fills formed late in the tectonic history and at relatively low temperatures (100-200°C) and in many cases appear to represent a final phase of fluid flow and mineralisation developed during the final stages of exhumation. In the northern part of the Adamello pluton in the Italian Alps, a geometrically complex and kinematically diverse set of zeolite bearing faults and veins is well exposed in the deformed tonalites associated with the Gole Larghe Fault Zone (GLFZ). These features post date all other deformation structures in the pluton, including cooling joints (formed at >550°C), ductile shear zones (550-450°C) and the well-known assemblage of faults, cataclasites and pseudotachylytes (300-250°C) associated with the GLFZ. Three main groups of zeolite-bearing fractures are recognised based on differences in orientation and kinematics of associated shear fracture displacements. These are: i) E-W sinistral reverse thrusts; ii) NNE-SSW sinistral normal faults; and iii) NNW-SSE normal faults. All three groups are associated with the development of white, yellow and red-orange zeolite-rich veins and fault gouge. Individual fault zones are rarely more than a few metres wide and fault offsets are generally small (mostly < 5m). Minor fractures associated with each group display mutually cross-cutting relationships consistent with them all being broadly contemporaneous features. This is confirmed by thin section and XRD analyses which reveal a fairly uniform set of mineral fills (including laumontite ± scolecite ± prehnite ± clinochlore ± stilbite ± stellerite ± quartz ± microcline ± albite). All three fracture groups are hard linked, locally forming spectacular mineralised fracture meshes. These features

  8. [Computational fluid dynamics simulation of different impeller combinations in high viscosity fermentation and its application].

    PubMed

    Dong, Shuhao; Zhu, Ping; Xu, Xiaoying; Li, Sha; Jiang, Yongxiang; Xu, Hong

    2015-07-01

    Agitator is one of the essential factors to realize high efficient fermentation for high aerobic and viscous microorganisms, and the influence of different impeller combination on the fermentation process is very important. Welan gum is a microbial exopolysaccharide produced by Alcaligenes sp. under high aerobic and high viscos conditions. Computational fluid dynamics (CFD) numerical simulation was used for analyzing the distribution of velocity, shear rate and gas holdup in the welan fermentation reactor under six different impeller combinations. The best three combinations of impellers were applied to the fermentation of welan. By analyzing the fermentation performance, the MB-4-6 combination had better effect on dissolved oxygen and velocity. The content of welan was increased by 13%. Furthermore, the viscosity of production were also increased.

  9. Corrosion of Nickel-Based Alloys in Ultra-High Temperature Heat Transfer Fluid

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Reddy, Ramana G.

    2017-03-01

    MgCl2-KCl binary system has been proposed to be used as high temperature reactor coolant. Due to its relatively low melting point, good heat capacity and excellent thermal stability, this system can also be used in high operation temperature concentrating solar power generation system as heat transfer fluid (HTF). The corrosion behaviors of nickel based alloys in MgCl2-KCl molten salt system at 1,000 °C were determined based on long-term isothermal dipping test. After 500 h exposure tests under strictly maintained high purity argon gas atmosphere, the weight loss and corrosion rate analysis were conducted. Among all the tested samples, Ni-201 demonstrated the lowest corrosion rate due to the excellent resistance of Ni to high temperature element dissolution. Detailed surface topography and corrosion mechanisms were also determined by using scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS).

  10. Three-Dimensional Printing of Highly Conductive Carbon Nanotube Microarchitectures with Fluid Ink.

    PubMed

    Kim, Jung Hyun; Lee, Sanghyeon; Wajahat, Muhammad; Jeong, Hwakyung; Chang, Won Suk; Jeong, Hee Jin; Yang, Jong-Ryul; Kim, Ji Tae; Seol, Seung Kwon

    2016-09-27

    Moving printed electronics to three dimensions essentially requires advanced additive manufacturing techniques yielding multifunctionality materials and high spatial resolution. Here, we report the meniscus-guided 3D printing of highly conductive multiwall carbon nanotube (MWNT) microarchitectures that exploit rapid solidification of a fluid ink meniscus formed by pulling a micronozzle. To achieve high-quality printing with continuous ink flow through a confined nozzle geometry, that is, without agglomeration and nozzle clogging, we design a polyvinylpyrrolidone-wrapped MWNT ink with uniform dispersion and appropriate rheological properties. The developed technique can produce various desired 3D microstructures, with a high MWNT concentration of up to 75 wt % being obtained via post-thermal treatment. Successful demonstrations of electronic components such as sensing transducers, emitters, and radio frequency inductors are also described herein. We expect that the technique presented in this study will facilitate selection of diverse materials in 3D printing and enhance the freedom of integration for advanced conceptual devices.

  11. High resolution coral records of reactive and micronutrient trace metals: Monitoring biological responses to flood plumes.

    NASA Astrophysics Data System (ADS)

    Wyndham, T. D.; McCulloch, M. T.; Decarlo, E. H.

    2004-12-01

    The influences of flood plumes on the coastal ocean are difficult to investigate because they are intermittent, transient and highly variable in nature. The application of trace metals in coral carbonates as proxy recorders of marine environmental conditions has been demonstrated as an excellent method for overcoming these difficulties. Coral records of trace metals have been widely used to provide historical records of physical impacts of flood plumes such changing salinity (δ O18), sediment load (Ba) and anthropogenic inputs such as heavy metal pollution (eg. Pb, Cd). Despite successful applications to physical properties, the use of coral records to monitoring the biologic responses to these changing environmental conditions has proved more difficult. With improvements in analytical techniques however, it is now possible to investigate coral records of reactive (rare earth elements) and micronutrient (eg Mn, Zn and Cu) trace metals, which can be used to more widely explore the biogeochemical implications of flood plumes to the coastal ocean. We have obtained high resolution temporal records of rare earth elements, Cu, Zn, Mn and Sn, from corals from two locations, (1) near Townsville on the Great Barrier Reef (GBR) and (2) Kaneohe Bay on Oahu, Hawaii. Both of these locations often display large phytoplankton blooms following flood events, providing a good opportunity to test the idea that coral records can be used to monitor the biological response to flood plumes. These coral records show significant responses to flood plumes that can only be attributed to biogeochemical cycling that occurs as a result of the flood plume influence, rather than the flood plume itself. Thus a mechanism for exploring the biological response to flood plumes is provided. It has generally proven difficult however, to interpret these coral records without a good understanding of the coastal processes. Therefore we also include evidence from direct trace metal measurements of a

  12. Internally supported flexible duct joint. [device for conducting fluids in high pressure systems

    NASA Technical Reports Server (NTRS)

    Kuhn, R. F., Jr. (Inventor)

    1975-01-01

    An internally supported, flexible duct joint for use in conducting fluids under relatively high pressures in systems where relatively large deflection angles must be accommodated is presented. The joint includes a flexible tubular bellows and an elongated base disposed within the bellows. The base is connected through radiating struts to the bellows near mid-portion and to each of the opposite end portions of the bellows through a pivotal connecting body. A motion-controlling linkage is provided for linking the connecting bodies, whereby angular displacement of the joint is controlled and uniformity in the instantaneous bend radius of the duct is achieved as deflection is imposed.

  13. New high-speed photography technique for observation of fluid flow in laser welding

    NASA Astrophysics Data System (ADS)

    Eriksson, Ingemar; Gren, Per; Powell, John; Kaplan, Alexander F. H.

    2010-10-01

    Recent developments in digital high-speed photography allow us to directly observe the surface topology and flow conditions of the melt surface inside a laser evaporated capillary. Such capillaries (known as keyholes) are a central feature of deep penetration laser welding. For the first time, it can be confirmed that the liquid capillary surface has a rippled, complex topology, indicative of subsurface turbulent flow. Manipulation of the raw data also provides quantitative measurements of the vertical fluid flow from the top to the bottom of the keyhole.

  14. In vitro digestibility of bovine β-casein with simulated and human oral and gastrointestinal fluids. Identification and IgE-reactivity of the resultant peptides.

    PubMed

    Benedé, Sara; López-Expósito, Iván; Giménez, Gustavo; Grishina, Galina; Bardina, Ludmilla; Sampson, Hugh A; Molina, Elena; López-Fandiño, Rosina

    2014-01-15

    Stability during digestion is considered an important feature in determining the allergenicity of food proteins. This study aimed to provide an immunological characterisation of the digestion products of the major cow's milk allergen β-casein (β-CN) produced by in vitro orogastrointestinal hydrolysis with simulated and human digestive fluids. β-CN was unaffected by oral digestion, but quickly broke down during the early stages of gastric digestion. The degradation with human fluids was faster than that with commercial enzymes. There were similarities in the peptide patterns of the hydrolysates produced in both models, showing 20 peptides in common after gastric digestion. After gastroduodenal digestion, the human fluids gave less numerous and shorter peptides. The IgE binding of most of the individual sera used to the hydrolysates produced with simulated and human fluids increased at the end of the gastric phase and decreased when the duodenal digestion was completed. Two IgE-binding synthetic peptides: β-CN (57-68) and β-CN (82-93), which matched fragments released by β-CN following in vitro digestion with simulated and human fluids, consisted of the most immunoreactive areas of the protein. The similarities found between the in vitro simulated digestion system and that using human digestive fluids suggest that the former would provide a reasonably good estimation of the potential allergenicity of protein digests.

  15. High emotional reactivity toward an experimenter affects participation, but not performance, in cognitive tests with common marmosets (Callithrix jacchus).

    PubMed

    Schubiger, Michèle N; Wüstholz, Florian L; Wunder, André; Burkart, Judith M

    2015-05-01

    When testing primates with cognitive tasks, it is usually not considered that subjects differ markedly in terms of emotional reactivity toward the experimenter, which potentially affects a subject's cognitive performance. We addressed this issue in common marmosets (Callithrix jacchus), a monkey species in which males tend to show stronger emotional reactivity in testing situations, whereas females have been reported to outperform males in cognitive tasks. In a two-phase experiment, we first quantified the emotional reactivity of 14 subjects toward four different experimenters performing a standardized behavioral action sequence and then assessed whether and how it affected the subjects' participation and performance in a subsequent object permanence task. A test session was terminated if a subject refused to make a choice in four consecutive trials. Highly emotionally aroused individuals, particularly males, were less likely to participate in the cognitive task and completed fewer trials. However, whenever they did participate and were attentive to the task, their performance was not affected. Our results suggest that differences in emotional reactivity toward an experimenter have no major impact on cognitive performance if strict criteria are applied on when to abandon a test session and if performance is corrected for attention to the test procedure. Furthermore, they suggest that the reported sex differences in cognitive performance in marmosets may be owing to motivational and attentional factors, rather than a difference in cognitive ability per se.

  16. Heat transfer for falling film evaporation of industrially relevant fluids up to very high Prandtl numbers

    NASA Astrophysics Data System (ADS)

    Gourdon, Mathias; Karlsson, Erik; Innings, Fredrik; Jongsma, Alfred; Vamling, Lennart

    2016-02-01

    In many industrial applications, falling film evaporation is an attractive technique for solvent removal due to high heat transfer and low residence times. Examples are the powder production in the dairy industry and in kraft pulp production process to remove water from so called black liquor. Common for both applications is that the fluids exhibit high viscosities in industrial practice. In this paper, results from experimental studies on both black liquor and a dairy product are reported for Prandtl numbers up to 800. The results are compared with several existing correlation in literature, and the need for a modified correlation is recognized especially to cover higher Prandtl-numbers. The following correlation for the turbulent flow region with 3 < Pr < 800 was derived from the data: {Nu}t = 0.0085 \\cdot Re^{0.2} \\cdot {Pr^{0.65}} The correlation has been compared to literature data from one additional study on two other fluids (propylene glycol and cyclohexanol) with fairly high Prandtl-numbers, from 40 to 58 and from 45 to 155 respectively and the agreement was within ±40 %.

  17. 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.

  18. New environmentally safe high-temperature water-based drilling-fluid system

    SciTech Connect

    Thaemlitz, C.J.; Patel, A.D.; Coffin, G.; Conn, L.

    1999-09-01

    A new, environmentally safe water-based polymer system has been developed for drilling applications with temperatures up to 232 C (450 F) and high pressures. The system components are newly developed synthetic polymers that do not contain chromium or other environmentally harmful materials. These new synthetic polymers are designed to perform specific functions at high temperatures and the innovative designs of these thermally stable polymers allow for the use of a minimum number of products in the formulation of high-temperature fluids. The new system consists of two basic polymeric components for rheology and filtration control at high temperatures. High-temperature fluid formulations are greatly simplified utilizing this new system, with only the two polymeric components being required, along with a pH control additive, weight material,l and small amounts of clay for filter cake quality. This simplicity is a significant advantage over traditional high-temperature systems, which normally require the use of a large number of additives to control or limit the effects of thermal degradation. The new system may be formulated with fresh water or sea water, providing flexibility for a variety of drilling environments. Excellent resistance to common contaminants, such as calcium and magnesium hardness and solids accumulation, is another important characteristic of this new system. This paper will review the previous state of the art with respect to high-temperature, water-based muds and will generically discuss the unique chemistry of the newly developed polymer system components. System formulation and application will be discussed.

  19. A rocking multianvil: elimination of chemical segregation in fluid-saturated high-pressure experiments

    NASA Astrophysics Data System (ADS)

    Schmidt, Max W.; Ulmer, Peter

    2004-04-01

    Fluid saturated high-pressure experiments often result in strongly zoned experimental charges, this hinders experimentation in chemically homogeneous systems which in turn has serious consequences on equilibration, reaction progress, and (apparent) phase stabilities. In order to overcome these problems, a 600-ton press accommodating either a multianvil or end-loaded piston cylinder module has been mounted in such a way that it can be turned by 180°, thus inverting its position in the gravity field. During turning, hydraulic pressure, heating power, and cooling water remain connected allowing fully controlled pressures and temperatures during experiments. A series of experiments at 13 GPa, 950°C, on a serpentine bulk composition in the MgO-SiO 2-H 2O system demonstrates that continuous turning at a rate of 2 turns/min results in a nearly homogeneous charge composed of phase E + enstatite. The same experiment at static conditions resulted in four mineral zones: quench phase E, enstatite, enstatite + phase E, and phase E + phase A. Phase A disappears in experiments at a turning rate ≥1 turn/min. A static 15-min experiment shows that zonation already forms within this short time span. Placing two short capsules within a single static experiment reveals that the fluid migrates to the hot spot in each capsule and is not gravitationally driven toward the top. The zonation pattern follows isotherms within the capsule, and the degree of zonation increases with temperature gradient (measured as 10 °C within a capsule) and run time. Our preferred interpretation is that Soret diffusion causes a density-stratified fluid within the capsule that does not convect in a static experiment and results in temperature dependant chemical zonation. The aggravation of zonation and appearance of additional phases with run time can be explained with a dissolution-reprecipitation process where the cold spot of the capsule is relatively MgO enriched and the hot spot relatively SiO 2 and H

  20. Profile of Trypanosoma cruzi Reactivity in a Population at High Risk for Endemic Pemphigus Foliaceus (Fogo Selvagem)

    PubMed Central

    Sousa, Joaquim X.; Diaz, Luis A.; Eaton, Donald P.; Hans-Filho, Günter; Lanzani de Freitas, Elder; Delgado, Livia; Ichimura, Ligia Maria F.; Cristaldi, Flávia; Orlandi, Renata; Kesper, Norival; Umezawa, Eufrosina S.; Rivitti, Evandro A.; Aoki, Valeria

    2012-01-01

    Fogo Selvagem (FS) is an autoimmune bullous disease with pathogenic IgG autoantibodies recognizing desmoglein 1 (Dsg1), a desmosomal glycoprotein. In certain settlements of Brazil, a high prevalence of FS (3%) is reported, suggesting environmental factors as triggers of the autoimmune response. Healthy individuals from endemic areas recognize nonpathogenic epitopes of Dsg1, and exposure to hematophagous insects is a risk factor for FS. Fogo selvagem and Chagas disease share some geographic sites, and anti-Dsg1 has been detected in Chagas patients. Indeterminate Chagas disease was identified in a Brazilian Amerindian population of high risk for FS. In counterpart, none of the FS patients living in the same geographic region showed reactivity against Trypanosoma cruzi. The profile of anti-Dsg1 antibodies showed positive results in 15 of 40 FS sera and in 33 of 150 sera from healthy individuals from endemic FS sites, and no cross-reactivity between Chagas disease and FS was observed. PMID:22826496

  1. A method for temperature estimation in high-temperature geothermal reservoirs by using synthetic fluid inclusions

    NASA Astrophysics Data System (ADS)

    Ruggieri, Giovanni; Orlando, Andrea; Chiarantini, Laura; Borrini, Daniele; Weisenberger, Tobias B.

    2016-04-01

    Super-hot geothermal systems in magmatic areas are a possible target for the future geothermal exploration either for the direct exploitation of fluids or as a potential reservoirs of Enhanced Geothermal Systems. Reservoir temperature measurements are crucial for the assessment of the geothermal resources, however temperature determination in the high-temperature (>380°C) zone of super-hot geothermal systems is difficult or impossible by using either mechanical temperature and pressure gauges (Kuster device) and electronic devices. In the framework of Integrated Methods for Advanced Geothermal Exploration (IMAGE) project, we developed a method to measure high reservoir temperature by the production of synthetic fluid inclusions within an apparatus that will be placed in the high-temperature zone of geothermal wells. First experiments were carried out by placing a gold capsule containing pre-fractured quartz and an aqueous solution (10 wt.% NaCl + 0.4 wt.% NaOH) in an externally heated pressure vessel. Experimental pressure-temperature conditions (i.e. 80-300 bars and 280-400°C) were set close to the liquid/vapour curve of pure H2O or along the H2O critical isochore. The experiments showed that synthetic fluid inclusions form within a relatively short time (even in 48 hours) and that temperatures calculated from homogenization temperatures and isochores of newly formed inclusions are close to experimental temperatures. A second set of laboratory experiments were carried out by using a stainless steel micro-rector in which a gold capsule (containing the pre-fractured quartz and the aqueous solution) was inserted together with an amount of distilled water corresponding to the critical density of water. These experiments were conducted by leaving the new micro-reactor within a furnace at 400°C and were aimed to reproduce the temperature existing in super-hot geothermal wells. Synthetic fluid inclusions formed during the experiments had trapping temperature

  2. Development of Highly Durable and Reactive Regenerable Magnesium-Based Sorbents for CO2 Separation in Coal Gasification Process

    SciTech Connect

    Javad Abbasian; Armin Hassanzadeh Khayyat; Rachid B. Slimane

    2005-06-01

    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 sorbents 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 magnitude

  3. Allocating Deceased Donor Kidneys to Candidates with High Panel–Reactive Antibodies

    PubMed Central

    Gebel, Howard M.; Kasiske, Bertram L.; Gustafson, Sally K.; Pyke, Joshua; Shteyn, Eugene; Bray, Robert A.; Snyder, Jon J.; Friedewald, John J.; Segev, Dorry L.

    2016-01-01

    Background and objectives In December of 2014, the Organ Procurement and Transplant Network implemented a new Kidney Allocation System (KAS) for deceased donor transplant, with increased priority for highly sensitized candidates (calculated panel–reactive antibody [cPRA] >99%). We used a modified version of the new KAS to address issues of access and equity for these candidates. Design, setting, participants, & measurements In a simulation, 10,988 deceased donor kidneys transplanted into waitlisted recipients in 2010 were instead allocated to candidates with cPRA≥80% (n=18,004). Each candidate’s unacceptable donor HLA antigens had been entered into the allocation system by the transplant center. In simulated match runs, kidneys were allocated sequentially to adult ABO identical or permissible candidates with cPRA 100%, 99%, 98%, etc. to 80%. Allocations were restricted to donor/recipient pairs with negative virtual crossmatches. Results The simulation indicated that 2111 of 10,988 kidneys (19.2%) would have been allocated to patients with cPRA 100% versus 74 of 10,988 (0.7%) that were actually transplanted. Of cPRA 100% candidates, 74% were predicted to be compatible with an average of six deceased donors; the remaining 26% seemed to be incompatible with every deceased donor organ that entered the system. Of kidneys actually allocated to cPRA 100% candidates in 2010, 66% (49 of 74) were six–antigen HLA matched/zero–antigen mismatched (HLA-A, -B, and -DR) with their recipients versus only 11% (237 of 2111) in the simulation. The simulation predicted that 10,356 of 14,433 (72%) candidates with cPRA 90%–100% could be allocated an organ compared with 7.3% who actually underwent transplant. Conclusions Data in this simulation are consistent with early results of the new KAS; specifically, nearly 20% of deceased donor kidneys were (virtually) compatible with cPRA 100% candidates. Although most of these candidates were predicted to be compatible with multiple

  4. Pareto optimal calibration of highly nonlinear reactive transport groundwater models using particle swarm optimization

    NASA Astrophysics Data System (ADS)

    Siade, A. J.; Prommer, H.; Welter, D.

    2014-12-01

    Groundwater management and remediation requires the implementation of numerical models in order to evaluate the potential anthropogenic impacts on aquifer systems. In many situations, the numerical model must, not only be able to simulate groundwater flow and transport, but also geochemical and biological processes. Each process being simulated carries with it a set of parameters that must be identified, along with differing potential sources of model-structure error. Various data types are often collected in the field and then used to calibrate the numerical model; however, these data types can represent very different processes and can subsequently be sensitive to the model parameters in extremely complex ways. Therefore, developing an appropriate weighting strategy to address the contributions of each data type to the overall least-squares objective function is not straightforward. This is further compounded by the presence of potential sources of model-structure errors that manifest themselves differently for each observation data type. Finally, reactive transport models are highly nonlinear, which can lead to convergence failure for algorithms operating on the assumption of local linearity. In this study, we propose a variation of the popular, particle swarm optimization algorithm to address trade-offs associated with the calibration of one data type over another. This method removes the need to specify weights between observation groups and instead, produces a multi-dimensional Pareto front that illustrates the trade-offs between data types. We use the PEST++ run manager, along with the standard PEST input/output structure, to implement parallel programming across multiple desktop computers using TCP/IP communications. This allows for very large swarms of particles without the need of a supercomputing facility. The method was applied to a case study in which modeling was used to gain insight into the mobilization of arsenic at a deepwell injection site

  5. In vitro Ca-45/++/ uptake and exchange by otoconial complexes in high and low K/+/Na/+/ fluids

    NASA Technical Reports Server (NTRS)

    Ross, M. D.; Pote, K. G.; Cloke, P. L.; Corson, C.

    1980-01-01

    Recently, data have been accumulating to indicate that saccular and utricular otoconial complexes of the gravity receptor organs are dynamic and interact constantly with their environment. This study investigates the possibility that the ionic composition of the surrounding fluid influences calcium ion binding and release, and explores the importance of the K(+)/Na(+) ratio. Two in-vitro methods were developed, the first of which employed artificial endolymph and perilymph while ionically balanced fluids in which only the K(+)/Na(+) was altered were used in the second. The ability of rat complexes to take up Ca-45(++) during incubation with these fluids was assessed using liquid scintillation spectrometry. In vitro uptake of Ca-45(++) was greater in fluids with a high K(+)/Na(+) ratio than in fluids in which the ratio was low. The ability of the complexes to take up Ca-45(++) appeared to decline with age.

  6. Process stabilization by peak current regulation in reactive high-power impulse magnetron sputtering of hafnium nitride

    NASA Astrophysics Data System (ADS)

    Shimizu, T.; Villamayor, M.; Lundin, D.; Helmersson, U.

    2016-02-01

    A simple and cost effective approach to stabilize the sputtering process in the transition zone during reactive high-power impulse magnetron sputtering (HiPIMS) is proposed. The method is based on real-time monitoring and control of the discharge current waveforms. To stabilize the process conditions at a given set point, a feedback control system was implemented that automatically regulates the pulse frequency, and thereby the average sputtering power, to maintain a constant maximum discharge current. In the present study, the variation of the pulse current waveforms over a wide range of reactive gas flows and pulse frequencies during a reactive HiPIMS process of Hf-N in an Ar-N2 atmosphere illustrates that the discharge current waveform is a an excellent indicator of the process conditions. Activating the reactive HiPIMS peak current regulation, stable process conditions were maintained when varying the N2 flow from 2.1 to 3.5 sccm by an automatic adjustment of the pulse frequency from 600 Hz to 1150 Hz and consequently an increase of the average power from 110 to 270 W. Hf-N films deposited using peak current regulation exhibited a stable stoichiometry, a nearly constant power-normalized deposition rate, and a polycrystalline cubic phase Hf-N with (1 1 1)-preferred orientation over the entire reactive gas flow range investigated. The physical reasons for the change in the current pulse waveform for different process conditions are discussed in some detail.

  7. Large-scale reactive molecular dynamics simulation and kinetic modeling of high-temperature pyrolysis of the Gloeocapsomorphaprisca microfossils.

    PubMed

    Zou, Chenyu; Raman, Sumathy; van Duin, Adri C T

    2014-06-12

    The ability to predict accurately the thermal conversion of complex carbonaceous materials is of value in both petroleum exploration and refining operations. Modeling the thermal cracking of kerogen under basinal heating conditions improves the predrill prediction of oil and gas yields and quality, thereby ultimately lowering the exploration risk. Modeling the chemical structure and reactivity of asphaltene from petroleum vacuum residues enables prediction of coke formation and properties in refinery processes, thereby lowering operating cost. The chemical structure-chemical yield modeling (CS-CYM) developed by Freund et al. is more rigorous, time-consuming, and requires a great deal of chemical insight into reaction network and reaction kinetics. The present work explores the applicability of a more fundamental atomistic simulation using the quantum mechanically based reactive force field to predict the product yield and overall kinetics of decomposition of two biopolymers, namely, the Kukersite and Gutternberg. Reactive molecular dynamics (RMD) simulations were performed on systems consisting of 10(4) to 10(5) atoms at different densities and temperatures to derive the overall kinetic parameters and a lumped kinetic model for pyrolysis. The kinetic parameters derived from the simulated pyrolysis of an individual component and the mixture of all four components in Guttenberg reveal the role of cross-talk between the fragments and enhanced reactivity of component A by radicals from other components. The Arrhenius extrapolation of the model yields reasonable prediction for the overall barrier for cracking. Because simulations were run at very high temperature (T > 1500 K) to study cracking within the simulation time of up to 1 ns, it, however, led to the entropically favored ethylene formation as a dominant decomposition route. Future work will focus on evaluating the applicability of accelerated reactive MD approaches to study cracking.

  8. A XANES study of Cu speciation in high-temperature brines using synthetic fluid inclusions

    SciTech Connect

    Berry, Andrew J.; Hack, Alistair C.; Mavrogenes, John A.; Newville, Matthew; Sutton, Stephen R.

    2010-12-03

    Cu K-edge X-ray absorption near edge structure (XANES) spectra were recorded from individual synthetic brine fluid inclusions as a function of temperature up to 500 C. The inclusions serve as sample cells for high-temperature spectroscopic studies of aqueous Cu-Cl speciation. Cu{sup +} and Cu{sup 2+} can both be identified from characteristic pre-edge features. Mixed oxidation states can be deconvoluted using linear combinations of Cu{sup +} and Cu{sup 2+} spectra. This work illustrates how complex Cu XANES spectra can be interpreted successfully. Cu{sup 2+} is the stable oxidation state in solution at room temperature and Cu{sup +} at high temperatures. The change in oxidation state with temperature was completely reversible. Cu{sup +} was found to occur exclusively as the linear species [CuCl{sub 2}]{sup -} in solutions containing KCl with Cu:Cl ratios up to 1:6. In the absence of K{sup +}, there is evidence for higher order coordination of Cu{sup +}, in particular the tetrahedral complex [CuCl{sub 4}]{sup 3-}. The importance of such complexes in natural ore-forming fluids is yet to be determined, but may explain the vapor-phase partitioning of Cu as a Cl complex from a Cl-rich brine.

  9. Coupled Fluids-Radiation Analysis of a High-Mass Mars Entry Vehicle

    NASA Technical Reports Server (NTRS)

    Palmer, Grant; Allen, Gary; Tang, Chun; Brown, Jim

    2011-01-01

    The NEQAIR line-by-line radiation code has been incorporated into the DPLR Navier-Stokes flow solver such that the NEQAIR subroutines are now callable functions of DPLR. The coupled DPLR-NEQAIR code was applied to compute the convective and radiative heating rates over high-mass Mars entry vehicles. Two vehicle geometries were considered - a 15 m diameter 70-degree sphere cone configuration and a slender, mid-L/D vehicle with a diameter of 5 m called an Ellipsled. The entry masses ranged from 100 to 165 metric tons. Solutions were generated for entry velocities ranging from 6.5 to 9.1 km/s. The coupled fluids-radiation solutions were performed at the peak heating location along trajectories generated by the Traj trajectory analysis code. The impact of fluids-radiation coupling is a function of the level of radiative heating and the freestream density and velocity. For the high-mass Mars vehicles examined in this study, coupling effects were greatest for entry velocities above 8.5 km/s where the surface radiative heating was reduced by up 17%. Generally speaking, the Ellipsled geometry experiences a lower peak radiative heating rate but a higher peak turbulent convective heating rate than the MSL-based vehicle.

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

    PubMed

    Peer, Andreas; Teschner, Matthias

    2016-12-06

    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.

  11. Unusually high reactivity of apolipoprotein B-100 among proteins to radical reactions induced in human plasma.

    PubMed

    Hashimoto, R; Narita, S; Yamada, Y; Tanaka, K; Kojo, S

    2000-01-17

    Relative reactivities of proteins to radical reactions caused in human plasma were studied for the first time utilizing an immunoblotting assay. When radical reactions were caused by Cu(2+), apolipoprotein B-100 (apoB) underwent extensive fragmentation concurrently with the decrease in alpha-tocopherol, while human serum albumin (HSA) and transferrin (TF) were not decreased at all. When radical reactions were initiated by Cu(2+) with hydrogen peroxide or 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH), alpha-tocopherol and apoB were also decreased steadily but HSA and TF were not decreased. These observations indicate that apoB is extremely reactive, even comparable to alpha-tocopherol, towards radical reactions. These results also suggest that the radical reaction of apoB is a possible process in vivo and it is involved in atherogenesis along with low density lipoprotein lipid peroxidation, which has been studied extensively.

  12. Features of Epstein-Barr virus reactivation after allogeneic hematopoietic cell transplantation in Korean children living in an area of high seroprevalence against Epstein-Barr virus.

    PubMed

    Han, Seung Beom; Bae, E Young; Lee, Jae Wook; Jang, Pil Sang; Lee, Dong-Gun; Chung, Nack-Gyun; Jeong, Dae Chul; Cho, Bin; Lee, Soon Ju; Kang, Jin Han; Kim, Hack-Ki

    2014-08-01

    The present study was conducted to investigate Epstein-Barr virus (EBV) reactivation after hematopoietic cell transplantation (HCT) in Korean children living in an area of a high seroprevalence against EBV and to determine the impact of recipient age on EBV reactivation. Medical records of 248 children and adolescents who had received allogeneic HCT were retrospectively reviewed. The trends of EBV reactivation and post-transplant lymphoproliferative disorders (PTLDs) were evaluated and compared between younger (≤10 years old) and older (11-20 years old) groups. EBV reactivation occurred in 177 cases (71.4 %) and high-level EBV reactivation, defined as a virus DNA titer of 300,000 copies/mL or higher, occurred in 21 cases (8.5 %). PTLD was diagnosed in five cases (2.0 %), and one of these patients died. The EBV reactivation rate was not significantly different between the two age groups; however, high-level reactivation and PTLD were more significantly frequent in the older than in the younger group (P = 0.030 and P = 0.026, respectively). In conclusion, older children and adolescents are more likely to experience high-level EBV reactivation and PTLDs, and higher EBV DNA titers than those previously reported may be a predictor of PTLD in areas with a high seroprevalence against EBV.

  13. High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HRMAS NMR) for Studies of Reactive Fabrics

    DTIC Science & Technology

    2015-11-01

    PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Director, ECBC, ATTN: RDCB-DRT-T, APG, MD 21010-5424  Leidos, Inc., P.O. Box 68, Gunpowder, MD 21010...0068     8. PERFORMING ORGANIZATION REPORT NUMBER ECBC-TR-1326 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR...HD Reactive polymer GD  16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE

  14. Chemical reactivity of CVC and CVD SiC with UO2 at high temperatures

    DOE PAGES

    Silva, Chinthaka M.; Katoh, Yutai; Voit, Stewart L.; ...

    2015-02-11

    Two types of silicon carbide (SiC) synthesized using two different vapor deposition processes were embedded in UO2 pellets and evaluated for their potential chemical reaction with UO2. While minor reactivity between chemical-vapor-composited (CVC) SiC and UO2 was observed at comparatively low temperatures of 1100 and 1300 C, chemical-vapor-deposited (CVD) SiC did not show any such reactivity, according to microstructural investigations. But, both CVD and CVC SiCs showed some reaction with UO2 at a higher temperature (1500 C). Elemental maps supported by phase maps obtained using electron backscatter diffraction indicated that CVC SiC was more reactive than CVD SiC at 1500more » C. Moreover, this investigation indicated the formation of uranium carbides and uranium silicide chemical phases such as UC, USi2, and U3Si2 as a result of SiC reaction with UO2.« less

  15. High reactivity of nanosized niobium oxide cluster cations in methane activation: A comparison with vanadium oxides

    SciTech Connect

    Ding, Xun-Lei E-mail: chemzyx@iccas.ac.cn; Wang, Dan; Wu, Xiao-Nan; Li, Zi-Yu; Zhao, Yan-Xia E-mail: chemzyx@iccas.ac.cn; He, Sheng-Gui

    2015-09-28

    The reactions between methane and niobium oxide cluster cations were studied and compared to those employing vanadium oxides. Hydrogen atom abstraction (HAA) reactions were identified over stoichiometric (Nb{sub 2}O{sub 5}){sub N}{sup +} clusters for N as large as 14 with a time-of-flight mass spectrometer. The reactivity of (Nb{sub 2}O{sub 5}){sub N}{sup +} clusters decreases as the N increases, and it is higher than that of (V {sub 2}O{sub 5}){sub N}{sup +} for N ≥ 4. Theoretical studies were conducted on (Nb{sub 2}O{sub 5}){sub N}{sup +} (N = 2–6) by density functional calculations. HAA reactions on these clusters are all favorable thermodynamically and kinetically. The difference of the reactivity with respect to the cluster size and metal type (Nb vs V) was attributed to thermodynamics, kinetics, the electron capture ability, and the distribution of the unpaired spin density. Nanosized Nb oxide clusters show higher HAA reactivity than V oxides, indicating that niobia may serve as promising catalysts for practical methane conversion.

  16. Fluid-rock interaction and evolution of a high-pressure/low-temperature vein system in eclogite from New Caledonia: insights into intraslab fluid flow processes

    NASA Astrophysics Data System (ADS)

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

    2016-11-01

    A complex high-pressure/low-temperature vein system that cross-cuts eclogitic host rocks of the Pouébo Eclogite Melange (northern New Caledonia) records the prograde blueschist-to-eclogite transition and associated formation of garnet-quartz-phengite veins. Geothermobarometry (Grt-Cpx-Ph, Zr-in-rutile) and pseudosection calculations indicate peak metamorphic conditions of ca. 540 °C and 1.9-2.2 GPa. Petrological and geochemical observations as well as pseudosection modelling suggest that the main vein network is formed by dehydration processes that collected internally derived fluids related to the breakdown of hydrous phases (amphibole, chlorite, epidote) during prograde metamorphism. The lower solid volume of the newly formed phases and the associated increase in pore fluid pressure lead to the formation of veins that allowed for accumulation and channelized evacuation of these fluids. Such veins do not show metasomatic alteration selvages because the fluid-rock system had been in chemical equilibrium. A second vein type (transport veins) records the superimposed influx of external fluids with slightly different composition that most likely are related to similar dehydration reactions in other parts of the subducting slab. Due to the source-rock-imposed compositional differences, these fluids are not in equilibrium with the infiltrated rock volume and induce the formation of distinct metasomatic selvages by dissolution-precipitation processes. Mass-balance calculations show that Ca, Na and Li are added to the selvage by the external fluid. LILE and to a lesser extend also HREE are mobilized and removed from the selvage. The LREE are predominantly buffered by newly formed minerals (e.g. epidote). Petrological evidence implies that the studied vein system formed while the sample was still part of a coherent subducting slab. Rb-Sr geochronology indicates that this occurred at 38.2 ± 0.3 Ma. This age is ca. 6 myr younger than the hitherto presumed peak metamorphic

  17. 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.

  18. A compact high-performance low-field NMR apparatus for measurements on fluids at very high pressures and temperatures

    SciTech Connect

    Freedman, R.; Anand, V. Ganesan, K.; Tabrizi, P.; Torres, R.; Grant, B.; Catina, D.; Ryan, D.; Borman, C.; Krueckl, C.

    2014-02-15

    We discuss an innovative new high-performance apparatus for performing low-field Nuclear Magnetic Resonance (NMR) relaxation times and diffusion measurements on fluids at very high pressures and high temperatures. The apparatus sensor design and electronics specifications allow for dual deployment either in a fluid sampling well logging tool or in a laboratory. The sensor and electronics were designed to function in both environments. This paper discusses the use of the apparatus in a laboratory environment. The operating temperature and pressure limits, and the signal-to-noise ratio (SNR) of the new system exceed by a very wide margin what is currently possible. This major breakthrough was made possible by a revolutionary new sensor design that breaks many of the rules of conventional high pressure NMR sensor design. A metallic sample holder capable of operating at high pressures and temperatures is provided to contain the fluid under study. The sample holder has been successfully tested for operation up to 36 Kpsi. A solenoid coil wound on a slotted titanium frame sits inside the metallic sample holder and serves as an antenna to transmit RF pulses and receive NMR signals. The metal sample holder is sandwiched between a pair of gradient coils which provide a linear field gradient for pulsed field gradient diffusion measurements. The assembly sits in the bore of a low-gradient permanent magnet. The system can operate over a wide frequency range without the need for tuning the antenna to the Larmor frequency. The SNR measured on a water sample at room temperature is more than 15 times greater than that of the commercial low-field system in our laboratory. Thus, the new system provides for data acquisition more than 200 times faster than was previously possible. Laboratory NMR measurements of relaxations times and diffusion coefficients performed at pressures up to 25 Kpsi and at temperatures up to 175 °C with crude oils enlivened with dissolved hydrocarbon gases

  19. A compact high-performance low-field NMR apparatus for measurements on fluids at very high pressures and temperatures.

    PubMed

    Freedman, R; Anand, V; Grant, B; Ganesan, K; Tabrizi, P; Torres, R; Catina, D; Ryan, D; Borman, C; Krueckl, C

    2014-02-01

    We discuss an innovative new high-performance apparatus for performing low-field Nuclear Magnetic Resonance (NMR) relaxation times and diffusion measurements on fluids at very high pressures and high temperatures. The apparatus sensor design and electronics specifications allow for dual deployment either in a fluid sampling well logging tool or in a laboratory. The sensor and electronics were designed to function in both environments. This paper discusses the use of the apparatus in a laboratory environment. The operating temperature and pressure limits, and the signal-to-noise ratio (SNR) of the new system exceed by a very wide margin what is currently possible. This major breakthrough was made possible by a revolutionary new sensor design that breaks many of the rules of conventional high pressure NMR sensor design. A metallic sample holder capable of operating at high pressures and temperatures is provided to contain the fluid under study. The sample holder has been successfully tested for operation up to 36 Kpsi. A solenoid coil wound on a slotted titanium frame sits inside the metallic sample holder and serves as an antenna to transmit RF pulses and receive NMR signals. The metal sample holder is sandwiched between a pair of gradient coils which provide a linear field gradient for pulsed field gradient diffusion measurements. The assembly sits in the bore of a low-gradient permanent magnet. The system can operate over a wide frequency range without the need for tuning the antenna to the Larmor frequency. The SNR measured on a water sample at room temperature is more than 15 times greater than that of the commercial low-field system in our laboratory. Thus, the new system provides for data acquisition more than 200 times faster than was previously possible. Laboratory NMR measurements of relaxations times and diffusion coefficients performed at pressures up to 25 Kpsi and at temperatures up to 175 °C with crude oils enlivened with dissolved hydrocarbon gases

  20. A corrected particle method with high-order Taylor expansion for solving the viscoelastic fluid flow

    NASA Astrophysics Data System (ADS)

    Jiang, T.; Ren, J. L.; Lu, W. G.; Xu, B.

    2017-02-01

    In this paper, a corrected particle method based on the smoothed particle hydrodynamics (SPH) method with high-order Taylor expansion (CSPH-HT) for solving the viscoelastic flow is proposed and investigated. The validity and merits of the CSPH-HT method are first tested by solving the nonlinear high order Kuramoto-Sivishinsky equation and simulating the drop stretching, respectively. Then the flow behaviors behind two stationary tangential cylinders of polymer melt, which have been received little attention, are investigated by the CSPH-HT method. Finally, the CSPH-HT method is extended to the simulation of the filling process of the viscoelastic fluid. The numerical results show that the CSPH-HT method possesses higher accuracy and stability than other corrected SPH methods and is more reliable than other corrected SPH methods.

  1. Enhancing Understanding of High Energy Density Plasmas Using Fluid Modeling with Kinetic Closures

    NASA Astrophysics Data System (ADS)

    Hansen, David; Held, Eric; Srinivasan, Bhuvana; Masti, Robert; King, Jake

    2016-10-01

    This work seeks to understand possible stabilization mechanisms of the early-time electrothermal instability in the evolution of the Rayleigh-Taylor instability in MagLIF (Magnetized Liner Inertial Fusion) experiments. Such mechanisms may include electron thermal conduction, viscosity, and large magnetic fields. Experiments have shown that the high-energy density plasmas from wire-array implosions require physics modelling that goes well beyond simple models such as ideal MHD. The plan is to develop a multi-fluid extended-MHD model that includes kinetic closures for thermal conductivity, resistivity, and viscosity using codes that are easily available to the wider research community. Such an effort would provide the community with a well-benchmarked tool capable of advanced modeling of high-energy-density plasmas.

  2. A corrected particle method with high-order Taylor expansion for solving the viscoelastic fluid flow

    NASA Astrophysics Data System (ADS)

    Jiang, T.; Ren, J. L.; Lu, W. G.; Xu, B.

    2016-12-01

    In this paper, a corrected particle method based on the smoothed particle hydrodynamics (SPH) method with high-order Taylor expansion (CSPH-HT) for solving the viscoelastic flow is proposed and investigated. The validity and merits of the CSPH-HT method are first tested by solving the nonlinear high order Kuramoto-Sivishinsky equation and simulating the drop stretching, respectively. Then the flow behaviors behind two stationary tangential cylinders of polymer melt, which have been received little attention, are investigated by the CSPH-HT method. Finally, the CSPH-HT method is extended to the simulation of the filling process of the viscoelastic fluid. The numerical results show that the CSPH-HT method possesses higher accuracy and stability than other corrected SPH methods and is more reliable than other corrected SPH methods.

  3. Magnitude and reactivity consequences of moisture ingress into the modular High-Temperature Gas-Cooled Reactor core

    SciTech Connect

    Smith, O.L. )

    1992-12-01

    Inadvertent admission of moisture into the primary system of a modular high-temperature gas-cooled reactor has been identified in US Department of Energy-sponsored studies as an important safety concern. The work described here develops an analytical methodology to quantify the pressure and reactivity consequences of steam-generator tube rupture and other moisture-ingress-related incidents. Important neutronic and thermohydraulic processes are coupled with reactivity feedback and safety and control system responses. The rate and magnitude of steam buildup are found to be dominated by major system features such as break size compared with safety valve capacity and reliability and less sensitive to factors such as heat transfer coefficients. The results indicate that ingress transients progress at a slower pace than previously predicted by bounding analyses, with milder power overshoots and more time for operator or automatic corrective actions.

  4. Fluid injection induced seismicity reveals a NE dipping fault in the southeastern sector of the High Agri Valley (southern Italy)

    NASA Astrophysics Data System (ADS)

    Stabile, T. A.; Giocoli, A.; Perrone, A.; Piscitelli, S.; Lapenna, V.

    2014-08-01

    On 2 June 2006 the wastewater produced during the oil and gas field exploitation in High Agri Valley (southern Italy) started to be managed by disposal through pumping the fluids back into the subsurface at the Costa Molina 2 (CM2) injection well, located in the southeastern sector of the valley. The onset of microearthquakes (Ml ≤ 2) after 4 days at about 1.3 km SW of CM2 well suggests fluid injection induced seismicity by the diffusion of pore pressure. Moreover, the space-time evolution of 196 high-resolution relocated events reveals a previously unmapped NE dipping fault. We investigate the physical processes related to the fluid injection induced seismicity and delineate the previously unmapped fault by jointly analyzing seismicity data, geological observations, fluid injection data, the stratigraphic log of the CM2 well, and the electrical resistivity tomography survey carried out in the study area.

  5. Evaluation of Phenylnaphthalenes as Heat Transfer Fluids for High Temperature Energy Applications

    SciTech Connect

    McFarlane, Joanna; Luo, Huimin; Garland, Marc A; Steele, William V.

    2010-01-01

    The thermodynamic properties of 1- and 2-phenyl substituted polyaromatic hydrocarbons have been measured and estimated under conditions relevant to heat transport applications almost to the critical point. Densities, vapor pressures, and heat capacity measurements were used to derive critical temperature, pressure and density for the phenylnaphthalenes. The thermal and radiolytic stability of 1-phenylnaphthalene was examined using thermogravimetric analysis, differential scanning calorimetery, and gamma irradiation. Low vapor pressure and resistance to thermal decomposition may make phenylnaphthalenes suitable for heat transfer applications involving parabolic solar collectors. In particular, 1-phenylnaphthalene has an advantage over high temperature inorganic salts for applications up to 800 K because it is a liquid at temperatures at or close to ambient. Thermal cycling would have to be restricted to temperatures below the critical point to avoid degradation of the fluid. Radiation stability was also tested by a 100 kGy irradiation of 1-phenylnaphthalene in a Co-60 irradiator. NMR analysis indicated 1.7 mol.% degradation, which although lower than observed for tributylphosphate/kerosene benchmark fluids for nuclear applications, is higher than that seen in imidazolium ionic liquids.

  6. An atomic and molecular fluid model for efficient edge-plasma transport simulations at high densities

    NASA Astrophysics Data System (ADS)

    Rognlien, Thomas; Rensink, Marvin

    2016-10-01

    Transport simulations for the edge plasma of tokamaks and other magnetic fusion devices requires the coupling of plasma and recycling or injected neutral gas. There are various neutral models used for this purpose, e.g., atomic fluid model, a Monte Carlo particle models, transition/escape probability methods, and semi-analytic models. While the Monte Carlo method is generally viewed as the most accurate, it is time consuming, which becomes even more demanding for device simulations of high densities and size typical of fusion power plants because the neutral collisional mean-free path becomes very small. Here we examine the behavior of an extended fluid neutral model for hydrogen that includes both atoms and molecules, which easily includes nonlinear neutral-neutral collision effects. In addition to the strong charge-exchange between hydrogen atoms and ions, elastic scattering is included among all species. Comparisons are made with the DEGAS 2 Monte Carlo code. Work performed for U.S. DoE by LLNL under Contract DE-AC52-07NA27344.

  7. Laser Heated High Density Fluids Probed by Coherent Anti-Stokes Raman Spectroscopy

    SciTech Connect

    Baer, B J; Yoo, C

    2004-05-19

    We describe an integrated experimental method of Coherent Antistoke Raman Spectroscopy (CARS), laser-heating and diamond-anvil cell (DAC) technologies probing molecular vibrations of transparent molecular fluids at the pressure-temperature conditions of energetic detonation and Giant planetary interiors. In this method, we use a microfabricated metal toroid to conductively heat a surrounding transparent sample in a DAC, using a CW Nd:YLF laser. The laser is operated at a TEM{sub 01*} mode to match the shape of the toroid and thus produces a uniform heating area. The CARS probe utilizes two pulsed lasers with similar cavity lengths: a commercial narrow-band mode-locked Q-switched Nd:YAG laser and a home-built broadband dye laser. A strong CARS signal is then produced from the sample in the central region of laser-heated metal toroid where the two laser pulses spatially and temporally coincide. In this paper, we will demonstrate that this technique is capable of producing high quality vibrational spectra from nitrogen fluid above 2000 K and 13 GPa, where the application of spontaneous Raman spectroscopy is limited because of intense thermal radiation.

  8. 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.

  9. High temperature reactive ion etching of iridium thin films with aluminum mask in CF4/O2/Ar plasma

    NASA Astrophysics Data System (ADS)

    Yeh, Chia-Pin; Lisker, Marco; Kalkofen, Bodo; Burte, Edmund P.

    2016-08-01

    Reactive ion etching (RIE) technology for iridium with CF4/O2/Ar gas mixtures and aluminum mask at high temperatures up to 350 °C was developed. The influence of various process parameters such as gas mixing ratio and substrate temperature on the etch rate was studied in order to find optimal process conditions. The surface of the samples after etching was found to be clean under SEM inspection. It was also shown that the etch rate of iridium could be enhanced at higher process temperature and, at the same time, very high etching selectivity between aluminum etching mask and iridium could be achieved.

  10. Lax pair, conservation laws and Darboux transformation of the high-order Lax equation in fluid dynamics

    NASA Astrophysics Data System (ADS)

    Zheng, Wenxin; Wei, Guangmei

    2017-03-01

    KdV equation is investigated in fluid dynamics, plasma physics and other fields. By means of poseudopotential procedure, the high-order member of KdV hierarchy, ninth-order Lax's KdV equation in fluid dynamics is studied in this paper. Lax pair in AKNS form are derived from poseudopotential. Based on the Lax pair, an infinite number of conservation laws and Darboux transformation are constructed, and soliton solution is obtained by the Darboux transformation.

  11. Patient-Specific Simulations of Reactivity in Models of the Pulmonary Vasculature: A 3-D Numerical Study with Fluid-Structure Interaction

    NASA Astrophysics Data System (ADS)

    Hunter, Kendall; Zhang, Yanhang; Lanning, Craig

    2005-11-01

    Insight into the progression of pulmonary hypertension may be obtained from thorough study of vascular flow during reactivity testing, an invasive diagnostic procedure which can dramatically alter vascular hemodynamics. Diagnostic imaging methods, however, are limited in their ability to provide extensive data. Here we present detailed flow and wall deformation results from simulations of pulmonary arteries undergoing this procedure. Patient-specific 3-D geometric reconstructions of the first four branches of the pulmonary vasculature were obtained clinically and meshed for use with computational software. Transient simulations in normal and reactive states were obtained from four such models were completed with patient-specific velocity inlet conditions and flow impedance exit conditions. A microstructurally based orthotropic hyperelastic model that simulates pulmonary artery mechanics under normotensive and hypoxic hypertensive conditions treated wall constitutive changes due to pressure reactivity and arterial remodeling. Pressure gradients, velocity fields, arterial deformation, and complete topography of shear stress were obtained. These models provide richer detail of hemodynamics than can be obtained from current imaging techniques, and should allow maximum characterization of vascular function in the clinical situation.

  12. Synthesis of Highly Reactive Subnano-sized Zero-valent Iron using Smectite Clay Templates

    PubMed Central

    Gu, Cheng; Jia, Hanzhang; Li, Hui; Teppen, Brian J.; Boyd, Stephen A.

    2010-01-01

    A novel method was developed for synthesizing subnano-sized zero-valent iron (ZVI) using smectite clay layers as templates. Exchangeable Fe(III) cations compensating the structural negative charges of smectites were reduced with NaBH4, resulting in the formation of ZVI. The unique structure of smectite clay, in which isolated exchangeable Fe(III) cations reside near the sites of structural negative charges, inhibited the agglomeration of ZVI resulting in the formation of discrete regions of subnanoscale ZVI particles in the smectite interlayer regions. X-ray diffraction revealed an interlayer spacing of ~ 5 Å. The non-structural iron content of this clay yields a calculated ratio of two atoms of ZVI per three cation exchange sites, in full agreement with the XRD results since the diameter of elemental Fe is 2.5 Å. The clay-templated ZVI showed superior reactivity and efficiency compared to other previously reported forms of ZVI as indicated by the reduction of nitrobenzene; structural Fe within the aluminosilicate layers was nonreactive. At a 1:3 molar ratio of nitrobenzene:non-structural Fe, a reaction efficiency of 83% was achieved, and over 80% of the nitrobenzene was reduced within one minute. These results confirm that non-structural Fe from Fe(III)-smectite was reduced predominantly to ZVI which was responsible for the reduction of nitrobenzene to aniline. This new form of subnano-scale ZVI may find utility in the development of remediation technologies for persistent environmental contaminants, e.g. as components of constructed reactive domains such as reactive caps for contaminated sediments. PMID:20446730

  13. Preparation of highly selective solid-phase extractants for Cibacron reactive dyes using molecularly imprinted polymers.

    PubMed

    Al-Degs, Yahya S; Abu-Surrah, Adnan S; Ibrahim, Khalid A

    2009-02-01

    Selective polymeric extractants were prepared for preconcentration of Cibacron reactive red dye, a dye that is often applied with Cibacron reactive blue and Cibacron reactive yellow for dyeing of fabrics. The best extractant was fabricated (in chloroform) using methacrylic acid (as monomer), ethylene glycol dimethacrylate (as crosslinker), AIBN (as initiator for polymerization), and red dye as template molecule, with a molar stoichiometric ratio of 8.0:40.0:2.5:0.63, respectively. The structure of the molecularly imprinted polymer (MIP) was robust, and resisted dissolution up to 260 degrees C. Compared with the un-imprinted polymer, the imprinted product has a large specific surface area which improved its adsorption capacity. The effect of imprinting was obvious from the adsorption capacity measured at pH 4 for red dye (the imprinted molecule), which was increased from 24.0 to 79.3 mg g(-1) after imprinting. Equilibrium adsorption studies revealed that the dye-imprinted-polymer enables efficient extraction of red dye even in the presence of blue and yellow dyes which have similar chemical natures to the red dye. The selectivity coefficients S (red dye/dye), were 13.9 and 17.1 relative to the yellow and blue dyes, respectively. The MIP was found to be effective for red dye preconcentration, with a preconcentration factor of 100, from tap water and treated textile wastewater. The factors affecting extraction of red dye by the MIP were studied and optimized. Under the optimized extraction conditions, red dye was selectively quantified in the presence of other competing dyes at a concentration of 20 microg L(-1) from different water systems with satisfactory recoveries (91-95%) and RSD values (approximately 5.0%).

  14. Fluid imbalance

    MedlinePlus

    ... up in the body. This is called fluid overload (volume overload). This can lead to edema (excess fluid in ... Water imbalance; Fluid imbalance - dehydration; Fluid buildup; Fluid overload; Volume overload; Loss of fluids; Edema - fluid imbalance; ...

  15. High-Salt Diet Causes Osmotic Gradients and Hyperosmolality in Skin Without Affecting Interstitial Fluid and Lymph.

    PubMed

    Nikpey, Elham; Karlsen, Tine V; Rakova, Natalia; Titze, Jens M; Tenstad, Olav; Wiig, Helge

    2017-02-06

    The common notion is that the body Na(+) is maintained within narrow limits for fluid and blood pressure homeostasis. Several studies have, however, shown that considerable amounts of Na(+) can be retained or removed from the body without commensurate water loss and that the skin can serve as a major salt reservoir. Our own data from rats have suggested that the skin is hypertonic compared with plasma on salt storage and that this also applies to skin interstitial fluid. Even small electrolyte gradients between plasma and interstitial fluid would represent strong edema-generating forces. Because the water accumulation has been shown to be modest, we decided to reexamine with alternative methods in rats whether interstitial fluid is hypertonic during salt accumulation induced by high-salt diet (8% NaCl and 1% saline to drink) or deoxycorticosterone pellet implantation. These treatments resulted both in increased systemic blood pressure, skin salt, and water accumulation and in skin hyperosmolality. Interstitial fluid isolated from implanted wicks and lymph draining the skin was, however, isosmotic, and Na(+) concentration in fluid isolated by centrifugation and in lymph was not different from plasma. Interestingly, by eluting layers of the skin, we could show that there was an osmolality and urea gradient from epidermis to dermis. Collectively, our data suggest that fluid leaving the skin as lymph is isosmotic to plasma but also that the skin can differentially control its own electrolyte microenvironment by creating local gradients that may be functionally important.

  16. Applications of supercritical fluids.

    PubMed

    Brunner, Gerd

    2010-01-01

    This review discusses supercritical fluids in industrial and near-to-industry applications. Supercritical fluids are flexible tools for processing materials. Supercritical fluids have been applied to mass-transfer processes, phase-transition processes, reactive systems, materials-related processes, and nanostructured materials. Some applications are already at industrial capacity, whereas others remain under development. In addition to extraction, application areas include impregnation and cleaning, multistage countercurrent separation, particle formation, coating, and reactive systems such as hydrogenation, biomass gasification, and supercritical water oxidation. Polymers are modified with supercritical fluids, and colloids and emulsions as well as nanostructured materials exhibit interesting phenomena when in contact with supercritical fluids that can be industrially exploited. For these applications to succeed, the properties of supercritical fluids in combination with the materials processed must be clearly determined and fundamental knowledge of the complex behavior must be made readily available.

  17. Preparation of polypropylene (PP)/ethylene octene copolymer (EOC) thermoplastic vulcanizates (TPVs) by high energy electron reactive processing

    NASA Astrophysics Data System (ADS)

    Rajeshbabu, R.; Gohs, U.; Naskar, K.; Thakur, V.; Wagenknecht, U.; Heinrich, G.

    2011-12-01

    Thermoplastic vulcanizates (TPVs) based on 50/50 composition of PP/EOC blend were prepared by electron induced reactive processing. To facilitate dynamic crosslinking in the PP/EOC blend, a 1.5 MeV electron accelerator was directly coupled to an internal mixer to induce chemical reactions via high energy electrons under dynamic conditions of melt mixing process. This kind of setup has been conceptualized for the first time in our laboratory and termed as electron induced reactive processing (EIReP) technique. Mechanical, morphological, and rheological properties of PP/EOC TPVs were studied with special reference to the exposure time (16-64 s) keeping absorbed dose (100 kGy) and electron energy (1.5 MeV) invariable. Chain scission dominates over chain crosslinking in both EOC as well as PP phases with the increase in exposure time. The primary factor is found to be the predominance of oxidative degradation during electron induced reactive processing in air atmosphere. The above observation was supported by Fourier Transform Infrared analyses and gel content values. Furthermore, it was found that mechanical properties depend not only on the extent of degradation in the blend system but also on the state and the mode of dispersion of the blend components.

  18. An ionization region model of the reactive Ar/O2 high power impulse magnetron sputtering discharge

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Jon Tomas; Lundin, Daniel; Brenning, Nils; Raadu, Michel A.; Huo, Chunqing; Minea, Tiberiu

    2016-09-01

    A reactive ionization region model (R-IRM) is developed to describe the reactive Ar/O2 high power impulse magnetron sputtering (HiPIMS) discharge with titanium target. We compare the discharge properties when the discharge is operated in the two well established operating modes, the metal mode and the poisoned mode. Experimentally, it is found that in the metal mode the discharge current waveform displays a typical non-reactive evolution, while in the poisoned mode the discharge current waveform becomes distinctly triangular and the current increases significantly. Using the R-IRM we find that when the discharge is operated in the metal mode Ar+ and Ti+-ions contribute most significantly (roughly equal amounts) to the discharge current while in the poisoned mode the Ar+-ions contribute most significantly to the discharge current while the contribution of O+-ions and secondary electron emission is much smaller. Furthermore, we find that recycling of ionized atoms coming from the target are required for the current generation in both modes of operation. In the metal mode self-sputter recycling dominates and in the poisoned mode working gas recycling dominates, and it is concluded that the dominating type of recycling determines the discharge current waveform.

  19. Stratal disruption and development of mélange, Western Newfoundland: effect of high fluid pressure in an accretionary terrain during ophiolite emplacement

    NASA Astrophysics Data System (ADS)

    Waldron, J. W. F.; Turner, D.; Stevens, K. M.

    The Bay of Islands Ophiolite was emplaced onto the continental margin of North America during the mid-Ordovician Taconic orogeny, when tectonic slices of continental margin sediments were accreted to the moving allochthon. Tectonic slices grade into and are surrounded by mélange. Early fracture in sandstones formed without grain breakage and allowed penetration of liquid petroleum along fracture planes. Other fractures involved cataclastic flow and were sometimes re-activated during formation of later pressure solution cleavage. Shear-fracture and extension-fracture boudinage affect competent strata; extensional veins cut cement in limestone beds and are filled by shale, quartz, calcite and bitumen. Folds also formed, at a time when siltstone and sandstone were at least partially lithified. Mélange matrix shows abundant shear and extension fractures in a variety of orientations. Coaxial extension responsible for disruption of bedding can be explained by a brittle accretionary wedge model in which high fluid pressures resulted from tectonic dewatering of shales. Surface slope decreased as fluid pressure rose beneath the ophiolite, causing horizontal extension of the wedge. After escape of excess water the surface slope steepened again as renewed stacking occurred.

  20. Modeling psychotic and cognitive symptoms of affective disorders: Disrupted latent inhibition and reversal learning deficits in highly stress reactive mice.

    PubMed

    Knapman, A; Heinzmann, J-M; Holsboer, F; Landgraf, R; Touma, C

    2010-09-01

    Increased stress reactivity has repeatedly been reported in patients suffering from psychiatric diseases including schizophrenia and major depression. These disorders also have other symptoms in common, such as cognitive deficits and psychotic-like behavior. We have therefore investigated if increased stress reactivity is associated with these phenotypic endpoints in an animal model of affective disorders. The stress reactivity mouse model used in this study consists of three CD-1-derived mouse lines, that have been selectively bred for high (HR), intermediate (IR) or low (LR) stress reactivity. Male mice from these three breeding lines were subjected to a reversal learning task and latent inhibition (Li) was assessed using a conditioned taste aversion paradigm. Furthermore, as the dopaminergic system is involved in both Li and reversal learning, the dopamine 1 receptor (D1R), dopamine 2 receptor (D2R) and dopamine transporter (DAT) mRNA expression levels were assessed in relevant brain areas of these animals. The results demonstrate that HR mice show perseveration in the reversal learning task and have disrupted Li. Furthermore, compared to LR mice, HR mice have decreased D2R mRNA levels in the ventral tegmental area, as well as decreased D1R mRNA levels in the cingulate cortex, and an increased expression of D2R mRNA in the nucleus accumbens. Taken together, these results demonstrate that the HR mice display cognitive deficits associated with psychotic-like behavior, similar to those observed in patients suffering from schizophrenia and major depression and could be utilized in the search for better treatment strategies for these symptoms of psychiatric disorders.

  1. Small-Scale Metal Tanks for High Pressure Storage of Fluids

    NASA Technical Reports Server (NTRS)

    London, Adam (Inventor)

    2016-01-01

    Small scale metal tanks for high-pressure storage of fluids having tank factors of more than 5000 meters and volumes of ten cubic inches or less featuring arrays of interconnected internal chambers having at least inner walls thinner than gage limitations allow. The chambers may be arranged as multiple internal independent vessels. Walls of chambers that are also portions of external tank walls may be arcuate on the internal and/or external surfaces, including domed. The tanks may be shaped adaptively and/or conformally to an application, including, for example, having one or more flat outer walls and/or having an annular shape. The tanks may have dual-purpose inlet/outlet conduits of may have separate inlet and outlet conduits. The tanks are made by fusion bonding etched metal foil layers patterned from slices of a CAD model of the tank. The fusion bonded foil stack may be further machined.

  2. Turbo-alternator-compressor design for supercritical high density working fluids

    SciTech Connect

    Wright, Steven A.; Fuller, Robert L.

    2013-03-19

    Techniques for generating power are provided. Such techniques involve a thermodynamic system including a housing, a turbine positioned in a turbine cavity of the housing, a compressor positioned in a compressor cavity of the housing, and an alternator positioned in a rotor cavity between the turbine and compressor cavities. The compressor has a high-pressure face facing an inlet of the compressor cavity and a low-pressure face on an opposite side thereof. The alternator has a rotor shaft operatively connected to the turbine and compressor, and is supported in the housing by bearings. Ridges extending from the low-pressure face of the compressor may be provided for balancing thrust across the compressor. Seals may be positioned about the alternator for selectively leaking fluid into the rotor cavity to reduce the temperature therein.

  3. Viscous dissipation effects on heat transfer from turbulent flow with high Prandtl number fluids

    NASA Astrophysics Data System (ADS)

    Chung, B. T. F.; Pang, Y.; Thomas, L. C.

    A comprehensive surface renewal type model, namely, the surface rejuvenation model, is employed to determine the viscous dissipation effect on heat transfer from turbulent flow with high Prandtl number fluids. In this work, the probability distributions for the stochastic variables which include the approach distance, the contact time, the residence time, and the initial temperature profile of the incoming eddies near the wall region are utilized. The Nusselt number, recovery factor, and temperature profile are obtained in integral forms which are then solved numerically. The ratio of Nusselt numbers in the presence of viscous effect to that in the absence of dissipation is presented in terms of Brinkman number, Prandtl number and Reynolds number for both cases of wall heating and cooling. Comparisons of the predicted recovery factor for turbulent pipe flow are also made based on the present model, previous eddy diffusivity models and the elementary surface renewal model for a wide range of Prandtl number.

  4. High-Speed Transport of Fluid Drops and Solid Particles via Surface Acoustic Waves

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Bao, Xiaoqi; Sherrit, Stewart; Badescu, Mircea; Lih, Shyh-shiuh

    2012-01-01

    A compact sampling tool mechanism that can operate at various temperatures, and transport and sieve particle sizes of powdered cuttings and soil grains with no moving parts, has been created using traveling surface acoustic waves (SAWs) that are emitted by an inter-digital transducer (IDT). The generated waves are driven at about 10 MHz, and it causes powder to move towards the IDT at high speed with different speeds for different sizes of particles, which enables these particles to be sieved. This design is based on the use of SAWs and their propelling effect on powder particles and fluids along the path of the waves. Generally, SAWs are elastic waves propagating in a shallow layer of about one wavelength beneath the surface of a solid substrate. To generate SAWs, a piezoelectric plate is used that is made of LiNbO3 crystal cut along the x-axis with rotation of 127.8 along the y-axis. On this plate are printed pairs of fingerlike electrodes in the form of a grating that are activated by subjecting the gap between the electrodes to electric field. This configuration of a surface wave transmitter is called IDT. The IDT that was used consists of 20 pairs of fingers with 0.4-mm spacing, a total length of 12.5 mm. The surface wave is produced by the nature of piezoelectric material to contract or expand when subjected to an electric field. Driving the IDT to generate wave at high amplitudes provides an actuation mechanism where the surface particles move elliptically, pulling powder particles on the surface toward the wavesource and pushing liquids in the opposite direction. This behavior allows the innovation to separate large particles and fluids that are mixed. Fluids are removed at speed (7.5 to 15 cm/s), enabling this innovation of acting as a bladeless wiper for raindrops. For the windshield design, the electrodes could be made transparent so that they do not disturb the driver or pilot. Multiple IDTs can be synchronized to transport water or powder over larger

  5. Scale-up of the production of highly reactive biogenic magnetite nanoparticles using Geobacter sulfurreducens.

    PubMed

    Byrne, J M; Muhamadali, H; Coker, V S; Cooper, J; Lloyd, J R

    2015-06-06

    Although there are numerous examples of large-scale commercial microbial synthesis routes for organic bioproducts, few studies have addressed the obvious potential for microbial systems to produce inorganic functional biomaterials at scale. Here we address this by focusing on the production of nanoscale biomagnetite particles by the Fe(III)-reducing bacterium Geobacter sulfurreducens, which was scaled up successfully from laboratory- to pilot plant-scale production, while maintaining the surface reactivity and magnetic properties which make this material well suited to commercial exploitation. At the largest scale tested, the bacterium was grown in a 50 l bioreactor, harvested and then inoculated into a buffer solution containing Fe(III)-oxyhydroxide and an electron donor and mediator, which promoted the formation of magnetite in under 24 h. This procedure was capable of producing up to 120 g of biomagnetite. The particle size distribution was maintained between 10 and 15 nm during scale-up of this second step from 10 ml to 10 l, with conserved magnetic properties and surface reactivity; the latter demonstrated by the reduction of Cr(VI). The process presented provides an environmentally benign route to magnetite production and serves as an alternative to harsher synthetic techniques, with the clear potential to be used to produce kilogram to tonne quantities.

  6. Fluid flow through a high cell density fluidized-bed during centrifugal bioreactor culture.

    PubMed

    Detzel, Christopher J; Van Wie, Bernard J; Ivory, Cornelius F

    2010-01-01

    An increasing demand for products such as tissues, proteins, and antibodies from mammalian cell suspension cultures is driving interest in increasing production through high-cell density bioreactors. The centrifugal bioreactor (CCBR) retains cells by balancing settling forces with surface drag forces due to medium throughput and is capable of maintaining cell densities above 10(8) cells/mL. This article builds on a previous study where the fluid mechanics of an empty CCBR were investigated showing fluid flow is nonuniform and dominated by Coriolis forces, raising concerns about nutrient and cell distribution. In this article, we demonstrate that the previously reported Coriolis forces are still present in the CCBR, but masked by the presence of cells. Experimental dye injection observations during culture of 15 microm hybridoma cells show a continual uniform darkening of the cell bed, indicating the region of the reactor containing cells is well mixed. Simulation results also indicate the cell bed is well mixed during culture of mammalian cells ranging in size from 10 to 20 microm. However, simulations also allow for a slight concentration gradient to be identified and attributed to Coriolis forces. Experimental results show cell density increases from 0.16 to 0.26 when centrifugal force is doubled by increasing RPM from 650 to 920 at a constant inlet velocity of 6.5 cm/s; an effect also observed in the simulation. Results presented in this article indicate cells maintained in the CCBR behave as a high-density fluidized bed of cells providing a homogeneous environment to ensure optimal growth conditions.

  7. Laser-assisted inkjet printing of highly viscous fluids with sub-nozzle resolution

    NASA Astrophysics Data System (ADS)

    Delrot, Paul; Modestino, Miguel A.; Psaltis, Demetri; Moser, Christophe

    2016-04-01

    Drop-on-demand inkjet printing is mostly based on thermal and piezo-actuation, allowing for densely packed nozzles in inkjet printers. However, the droplet diameter is typically defined by the nozzle diameter, thus limiting the range of viscosity that can be jetted to 10-100 mPa.s to prevent nozzle clogging. Here, we present a laser-assisted system for the delivery of micro-droplets of highly viscous fluids with sub-nozzle resolution. Highly focused supersonic jets have recently been demonstrated by focusing a nanosecond pulse of light into a micro-capillary filled with dyed water, hence generating a cavitation bubble. The consequent pressure wave impact on the concave free surface of the liquid generated flow-focused micro-jets. We implemented this technique for the production of low velocity micro-droplets with photopolymer inks of increasing viscosity (0.6-148 mPa.s) into a 300 μm-wide glass capillary using low laser energies (3-70 μJ). Time-resolved imaging provided details on the droplet generation. Single micro-droplets of diameter 70-80 μm were produced on demand with inks of viscosity 0.6-9 mPa.s with good controllability and reproducibility, thus enabling to print two-dimensional patterns with a precision of 13 μm. Furthermore, the primary droplet produced with the most viscous fluid was about 66% of the capillary diameter. Preliminary results also showed that the process is linearly scalable to narrower capillaries (100-200 μm), thus paving the way for a compact laser-assisted inkjet printer. A possible application of the device would be additive manufacturing as the printed patterns could be consequently cured.

  8. Fluid Flow through a High Cell Density Fluidized-Bed during Centrifugal Bioreactor Culture

    PubMed Central

    Detzel, Christopher J.; Van Wie, Bernard J.; Ivory, Cornelius F.

    2010-01-01

    An increasing demand for products such as tissues, proteins, and antibodies from mammalian cell suspension cultures is driving interest in increasing production through high-cell density bioreactors. The centrifugal bioreactor (CCBR) retains cells by balancing settling forces with surface drag forces due to medium throughput and is capable of maintaining cell densities above 108 cells/mL. This article builds on a previous study where the fluid mechanics of an empty CCBR were investigated showing fluid flow is nonuniform and dominated by Coriolis forces, raising concerns about nutrient and cell distribution. In this article, we demonstrate that the previously reported Coriolis forces are still present in the CCBR, but masked by the presence of cells. Experimental dye injection observations during culture of 15 μm hybridoma cells show a continual uniform darkening of the cell bed, indicating the region of the reactor containing cells is well mixed. Simulation results also indicate the cell bed is well mixed during culture of mammalian cells ranging in size from 10 to 20 μm. However, simulations also allow for a slight concentration gradient to be identified and attributed to Coriolis forces. Experimental results show cell density increases from 0.16 to 0.26 when centrifugal force is doubled by increasing RPM from 650 to 920 at a constant inlet velocity of 6.5 cm/s; an effect also observed in the simulation. Results presented in this article indicate cells maintained in the CCBR behave as a high-density fluidized bed of cells providing a homogeneous environment to ensure optimal growth conditions. PMID:20205172

  9. Chemical and textural characteristics of multistage fluid inclusions with high Li/B ratio found from the Sanbagawa belt.

    NASA Astrophysics Data System (ADS)

    Yoshida, K.; Hirajima, T.

    2012-04-01

    Recent studies invoked that the variation of peculiar fluid soluble light elements, such as Li, B and Cl, are capable of suggesting generation depths of fluid released in subduction zones (e.g., Scambelluri et al., 2004; Bebout et al., 2007; Marschall et al., 2009). Crush-leached fluids extracted from quartz veins intercalated with metabasites of the Sanbagawa metamorphic belt show high Li and B concentrations, whose Li/B ratios show a positive correlation with metamorphic grade of the host rocks, i.e., from 0.02 for pumpellyite-actinolite facies to 0.27 for eclogite facies (Sengen et al., 2009). Furthermore, crush-leached fluids extracted from quartz veins intercalated with metasediments in proximal to the eclogite unit in the Besshi district show much higher Li/B ratio (ca. 0.36-1.99). Yoshida et al. (2011) pointed out that Li/B ratio of dehydrated fluids was controlled by the rock types of the host rocks, i.e., Li/B ratio of dehydrated fluids derived from tourmaline-free metasediments show much higher values than those expected from metabasites. Those obtained data suggest that the Li/B ratio of the deep fluid has a potential as a depth indicator but there remain many unknown factors for establishing it. The Li/B ratio of extracted fluid obtained by the crush-leached method integrates the whole fluid activities which the host rocks were taken place. To investigate the fluid activity history for the sample showing the highest Li/B ratio (1.99), detailed petrographical and microthemometric studies were performed. The studied sample IR04 is a foliation-parallel quartz vein intercalated with a Grt-Hbl-Ph schist probably derived from clay, whose peak P-T conditions are estimated as 600 °C and 1.3 GPa using pseudosection analysis. The quartz vein shows a foam microstructure, suggesting that low differential stress and high-T conditions were attained during its texture formation. Three types of fluid inclusions have been identified: the earliest one, FIA-I, is

  10. Microbial diversity in ultra-high-pressure rocks and fluids from the Chinese Continental Scientific Drilling Project in China.

    PubMed

    Zhang, Gengxin; Dong, Hailiang; Xu, Zhiqin; Zhao, Donggao; Zhang, Chuanlun

    2005-06-01

    Microbial communities in ultra-high-pressure (UHP) rocks and drilling fluids from the Chinese Continental Scientific Drilling Project were characterized. The rocks had a porosity of 1 to 3.5% and a permeability of approximately 0.5 mDarcy. Abundant fluid and gas inclusions were present in the minerals. The rocks contained significant amounts of Fe2O3, FeO, P2O5, and nitrate (3 to 16 ppm). Acridine orange direct counting and phospholipid fatty acid analysis indicated that the total counts in the rocks and the fluids were 5.2 x 10(3) to 2.4 x 10(4) cells/g and 3.5 x 10(8) to 4.2 x 10(9) cells/g, respectively. Enrichment assays resulted in successful growth of thermophilic and alkaliphilic bacteria from the fluids, and some of these bacteria reduced Fe(III) to magnetite. 16S rRNA gene analyses indicated that the rocks were dominated by sequences similar to sequences of Proteobacteria and that most organisms were related to nitrate reducers from a saline, alkaline, cold habitat; however, some phylotypes were either members of a novel lineage or closely related to uncultured clones. The bacterial communities in the fluids were more diverse and included Proteobacteria, Bacteroidetes, gram-positive bacteria, Planctomycetes, and Candidatus taxa. The archaeal diversity was lower, and most sequences were not related to any known cultivated species. Some archaeal sequences were 90 to 95% similar to sequences recovered from ocean sediments or other subsurface environments. Some archaeal sequences from the drilling fluids were >93% similar to sequences of Sulfolobus solfataricus, and the thermophilic nature was consistent with the in situ temperature. We inferred that the microbes in the UHP rocks reside in fluid and gas inclusions, whereas those in the drilling fluids may be derived from subsurface fluids.

  11. Microbial Diversity in Ultra-High-Pressure Rocks and Fluids from the Chinese Continental Scientific Drilling Project in China

    PubMed Central

    Zhang, Gengxin; Dong, Hailiang; Xu, Zhiqin; Zhao, Donggao; Zhang, Chuanlun

    2005-01-01

    Microbial communities in ultra-high-pressure (UHP) rocks and drilling fluids from the Chinese Continental Scientific Drilling Project were characterized. The rocks had a porosity of 1 to 3.5% and a permeability of ∼0.5 mDarcy. Abundant fluid and gas inclusions were present in the minerals. The rocks contained significant amounts of Fe2O3, FeO, P2O5, and nitrate (3 to 16 ppm). Acridine orange direct counting and phospholipid fatty acid analysis indicated that the total counts in the rocks and the fluids were 5.2 × 103 to 2.4 × 104 cells/g and 3.5 × 108 to 4.2 × 109 cells/g, respectively. Enrichment assays resulted in successful growth of thermophilic and alkaliphilic bacteria from the fluids, and some of these bacteria reduced Fe(III) to magnetite. 16S rRNA gene analyses indicated that the rocks were dominated by sequences similar to sequences of Proteobacteria and that most organisms were related to nitrate reducers from a saline, alkaline, cold habitat; however, some phylotypes were either members of a novel lineage or closely related to uncultured clones. The bacterial communities in the fluids were more diverse and included Proteobacteria, Bacteroidetes, gram-positive bacteria, Planctomycetes, and Candidatus taxa. The archaeal diversity was lower, and most sequences were not related to any known cultivated species. Some archaeal sequences were 90 to 95% similar to sequences recovered from ocean sediments or other subsurface environments. Some archaeal sequences from the drilling fluids were >93% similar to sequences of Sulfolobus solfataricus, and the thermophilic nature was consistent with the in situ temperature. We inferred that the microbes in the UHP rocks reside in fluid and gas inclusions, whereas those in the drilling fluids may be derived from subsurface fluids. PMID:15933024

  12. High-resolution compact shear stress sensor for direct measurement of skin friction in fluid flow

    NASA Astrophysics Data System (ADS)

    Xu, Muchen; Kim, Chang-Jin ``Cj''

    2015-11-01

    The high-resolution measurement of skin friction in complex flows has long been of great interest but also a challenge in fluid mechanics. Compared with indirect measurement methods (e.g., laser Doppler velocimetry), direct measurement methods (e.g., floating element) do not involve any analogy and assumption but tend to suffer from instrumentation challenges, such as low sensing resolution or misalignments. Recently, silicon micromachined floating plates showed good resolution and perfect alignment but were too small for general purposes and too fragile to attach other surface samples repeatedly. In this work, we report a skin friction sensor consisting of a monolithic floating plate and a high-resolution optical encoder to measure its displacement. The key for the high resolution is in the suspension beams, which are very narrow (e.g., 0.25 mm) to sense small frictions along the flow direction but thick (e.g., 5 mm) to be robust along all other directions. This compact, low profile, and complete sensor is easy to use and allows repeated attachment and detachment of surface samples. The sheer-stress sensor has been tested in water tunnel and towing tank at different flow conditions, showing high sensing resolution for skin friction measurement. Supported by National Science Foundation (NSF) (No. 1336966) and Defense Advanced Research Projects Agency (DARPA) (No. HR0011-15-2-0021).

  13. A family of high-order targeted ENO schemes for compressible-fluid simulations

    NASA Astrophysics Data System (ADS)

    Fu, Lin; Hu, Xiangyu Y.; Adams, Nikolaus A.

    2016-01-01

    Although classical WENO schemes have achieved great success and are widely accepted, they exhibit several shortcomings. They are too dissipative for direct simulations of turbulence and lack robustness when very-high-order versions are applied to complex flows. In this paper, we propose a family of high-order targeted ENO schemes which are applicable for compressible-fluid simulations involving a wide range of flow scales. In order to increase the numerical robustness as compared to very-high-order classical WENO schemes, the reconstruction dynamically assembles a set of low-order candidate stencils with incrementally increasing width. While discontinuities and small-scale fluctuations are efficiently separated, the numerical dissipation is significantly diminished by an ENO-like stencil selection, which either applies a candidate stencil with its original linear weight, or removes its contribution when it is crossed by a discontinuity. The background linear scheme is optimized under the constraint of preserving an approximate dispersion-dissipation relation. By means of quasi-linear analyses and practical numerical experiments, a set of case-independent parameters is determined. The general formulation of arbitrarily high-order schemes is presented in a straightforward way. A variety of benchmark-test problems, including broadband waves, strong shock and contact discontinuities are studied. Compared to well-established classical WENO schemes, the present schemes exhibit significantly improved robustness, low numerical dissipation and sharp discontinuity capturing. They are particularly suitable for DNS and LES of shock-turbulence interactions.

  14. 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.

  15. Comparison of osteoprotegerin to traditional atherosclerotic risk factors and high-sensitivity C-reactive protein for diagnosis of atherosclerosis.

    PubMed

    Mogelvang, Rasmus; Pedersen, Sune H; Flyvbjerg, Allan; Bjerre, Mette; Iversen, Allan Z; Galatius, Soren; Frystyk, Jan; Jensen, Jan S

    2012-02-15

    Atherosclerosis is the main cause of cardiovascular disease, but the extent of atherosclerosis in individual patients is difficult to estimate. A biomarker of the atherosclerotic burden would be very valuable. The aim of the present study was to evaluate the association of plasma osteoprotegerin (OPG) to clinical and subclinical atherosclerotic disease in a large community-based, cross-sectional population study. In the Copenhagen City Heart Study, OPG concentrations were measured in 5,863 men and women. A total of 494 participants had been hospitalized for ischemic heart disease or ischemic stroke, and compared to controls, this group with clinical atherosclerosis had higher mean OPG (1,773 vs 1,337 ng/L, p <0.001) and high-sensitivity C-reactive protein (2.3 vs 1.6 mg/L, p <0.001). In a multivariate model with age, gender, body mass index, hypertension, diabetes, hypercholesterolemia, smoking status, estimated glomerular filtration rate, high-sensitivity C-reactive protein, and OPG, OPG remained significantly associated with clinical atherosclerosis (p <0.01); high-sensitivity C-reactive protein, in contrast, did not (p = 0.74). In the control group without clinical atherosclerosis, OPG was independently associated with hypertension, diabetes, hypercholesterolemia, smoking, and subclinical peripheral atherosclerosis as measured by ankle brachial index. For each doubling of the plasma OPG concentration, the risk for subclinical peripheral atherosclerosis increased by 50% (p <0.001) after multivariate adjustment. In conclusion, OPG appears to be a promising biomarker of atherosclerosis that is independently associated with traditional risk factors of atherosclerosis, subclinical peripheral atherosclerosis, and clinical atherosclerotic disease such as ischemic heart disease and ischemic stroke.

  16. Protective mechanisms of helminths against reactive oxygen species are highly promising drug targets.

    PubMed

    Perbandt, Markus; Ndjonka, Dieudonne; Liebau, Eva

    2014-01-01

    Helminths that are the causative agents of numerous neglected tropical diseases continue to be a major problem for human global health. In the absence of vaccines, control relies solely on pharmacoprophylaxis and pharmacotherapy to reduce transmission and to relieve symptoms. There are only a few drugs available and resistance in helminths of lifestock has been observed to the same drugs that are also used to treat humans. Clearly there is an urgent need to find novel antiparasitic compounds. Not only are helminths confronted with their own metabolically derived toxic and redox-active byproducts but also with the production of reactive oxygen species (ROS) by the host immune system, adding to the overall oxidative burden of the parasite. Antioxidant enzymes of helminths have been identified as essential proteins, some of them biochemically distinct to their host counterpart and thus appealing drug targets. In this review we have selected a few enzymatic antioxidants of helminths that are thought to be druggable.

  17. Mechanism and Experimental Observability of Global Switching Between Reactive and Nonreactive Coordinates at High Total Energies

    NASA Astrophysics Data System (ADS)

    Teramoto, Hiroshi; Toda, Mikito; Takahashi, Masahiko; Kono, Hirohiko; Komatsuzaki, Tamiki

    2015-08-01

    We present a mechanism of global reaction coordinate switching, namely, a phenomenon in which the reaction coordinate dynamically switches to another coordinate as the total energy of the system increases. The mechanism is based on global changes in the underlying phase space geometry caused by a switching of dominant unstable modes from the original reactive mode to another nonreactive mode in systems with more than 2 degrees of freedom. We demonstrate an experimental observability to detect a reaction coordinate switching in an ionization reaction of a hydrogen atom in crossed electric and magnetic fields. For this reaction, the reaction coordinate is a coordinate along which electrons escape and its switching changes the escaping direction from the direction of the electric field to that of the magnetic field and, thus, the switching can be detected experimentally by measuring the angle-resolved momentum distribution of escaping electrons.

  18. Experimental design for reflection measurements of highly reactive liquid or solid substances with application to liquid sodium

    SciTech Connect

    Chan, S.H.; Gossler, A.A.

    1980-06-30

    A versatile goniometer system with associated electronic components and mechanical instruments has been assembled. It is designed to measure spectral, specular reflectances of highly reactive liquid or solid substances over a spectral range of 0.3 to 9 ..mu.. and incidence angles of 12 to 30/sup 0/ off the normal direction. The capability of measuring reflectances of liquid substances clearly distinguishes this experimental design from conventional systems which are applicable only to solid substances. This design has been used to measure the spectral, specular reflectance of liquid sodium and preliminary results obtained are compared with those of solid sodium measured by other investigators.

  19. High-throughput spectrophotometric assay of reactive oxygen species in serum.

    PubMed

    Hayashi, Ikue; Morishita, Yukari; Imai, Kazue; Nakamura, Masakazu; Nakachi, Kei; Hayashi, Tomonori

    2007-07-10

    The derivatives of reactive oxygen metabolites (D-ROM) test has been developed to determine the amount of oxygen-centered free radicals in a blood sample as a marker of oxidative stress. This study aims to improve the D-ROM test and develop an automated assay system by use of a clinical chemistry analyzer. Five microliters of serum was added to 1 well of a 96-well microtiter plate for a total 240microl of reaction solution containing alkylamine and metals. This was followed by automatic mixing, incubation and measurement of reactive oxygen species (ROS) levels as a color development at 505nm using a spectrophotometer with catalytic capability for transition metals. This assay system was used to measure serum levels of ROS in cigarette smokers and never-smokers, by way of example. The levels of serum ROS determined by this system correlate with the amounts of free radicals and peroxides, which reacted with various molecules in the body and formed stable metabolites. This test can use frozen sera as well as fresh ones. The inter- and intra-deviation of this system was within 5% and showed consistent linearity in the range between 4 and 500mg/l of hydrogen peroxides. Serum ROS levels among smokers increased with the number of cigarettes smoked per day (36.5% increment per pack per day; P<0.0001). This assay system will be a simple, inexpensive, and reliable tool for assessing oxidative stress in human populations. Our preliminary results on cigarette smoking imply that this assay system has potential for application in various epidemiological and clinical settings.

  20. Engineered diamond nanopillars as mobile probes for high sensitivity metrology in fluid

    NASA Astrophysics Data System (ADS)

    Andrich, P.; de Las Casas, C. F.; Heremans, F. J.; Awschalom, D. D.; Aleman, B. J.; Ohno, K.; Lee, J. C.; Hu, E. L.

    2015-03-01

    The nitrogen-vacancy (NV) center`s optical addressability and exceptional spin coherence properties at room temperature, along with diamond`s biocompatibility, has put this defect at the frontier of metrology applications in biological environments. To push the spatial resolution to the nanoscale, extensive research efforts focus on using NV centers embedded in nanodiamonds (NDs). However, this approach has been hindered by degraded spin coherence properties in NDs and the lack of a platform for spatial control of the nanoparticles in fluid. In this work, we combine the use of high quality diamond membranes with a top-down patterning technique to fabricate diamond nanoparticles with engineered and highly reproducible shape, size, and NV center density. We obtain NDs, easily releasable from the substrate into a water suspension, which contain single NV centers exhibiting consistently long spin coherence times (up to 700 μs). Additionally, we demonstrate highly stable, three-dimensional optical trapping of the nanoparticles within a microfluidic circuit. This level of control enables a bulk-like DC magnetic sensitivity and gives access to dynamical decoupling techniques on contactless, miniaturized diamond probes. This work was supported by DARPA, AFOSR, and the DIAMANT program.

  1. 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.

  2. Evaluation of a High-Throughput Peptide Reactivity Format Assay for Assessment of the Skin Sensitization Potential of Chemicals

    PubMed Central

    Wong, Chin Lin; Lam, Ai-Leen; Smith, Maree T.; Ghassabian, Sussan

    2016-01-01

    The direct peptide reactivity assay (DPRA) is a validated method for in vitro assessment of the skin sensitization potential of chemicals. In the present work, we describe a peptide reactivity assay using 96-well plate format and systematically identified the optimal assay conditions for accurate and reproducible classification of chemicals with known sensitizing capacity. The aim of the research is to ensure that the analytical component of the peptide reactivity assay is robust, accurate, and reproducible in accordance with criteria that are used for the validation of bioanalytical methods. Analytical performance was evaluated using quality control samples (QCs; heptapeptides at low, medium, and high concentrations) and incubation of control chemicals (chemicals with known sensitization capacity, weak, moderate, strong, extreme, and non-sensitizers) with each of three synthetic heptapeptides, viz Cor1-C420 (Ac-NKKCDLF), cysteine- (Ac-RFAACAA), and lysine- (Ac-RFAAKAA) containing heptapeptides. The optimal incubation temperature for all three heptapeptides was 25°C. Apparent heptapeptide depletion was affected by vial material composition. Incubation of test chemicals with Cor1-C420, showed that peptide depletion was unchanged in polypropylene vials over 3-days storage in an autosampler but this was not the case for borosilicate glass vials. For cysteine-containing heptapeptide, the concentration was not stable by day 3 post-incubation in borosilicate glass vials. Although the lysine-containing heptapeptide concentration was unchanged in both polypropylene and borosilicate glass vials, the apparent extent of lysine-containing heptapeptide depletion by ethyl acrylate, differed between polypropylene (24.7%) and glass (47.3%) vials. Additionally, the peptide-chemical complexes for Cor1-C420-cinnamaldehyde and cysteine-containing heptapeptide-2, 4-dinitrochlorobenzene were partially reversible during 3-days of autosampler storage. These observations further highlight

  3. Evaluation of a High-Throughput Peptide Reactivity Format Assay for Assessment of the Skin Sensitization Potential of Chemicals.

    PubMed

    Wong, Chin Lin; Lam, Ai-Leen; Smith, Maree T; Ghassabian, Sussan

    2016-01-01

    The direct peptide reactivity assay (DPRA) is a validated method for in vitro assessment of the skin sensitization potential of chemicals. In the present work, we describe a peptide reactivity assay using 96-well plate format and systematically identified the optimal assay conditions for accurate and reproducible classification of chemicals with known sensitizing capacity. The aim of the research is to ensure that the analytical component of the peptide reactivity assay is robust, accurate, and reproducible in accordance with criteria that are used for the validation of bioanalytical methods. Analytical performance was evaluated using quality control samples (QCs; heptapeptides at low, medium, and high concentrations) and incubation of control chemicals (chemicals with known sensitization capacity, weak, moderate, strong, extreme, and non-sensitizers) with each of three synthetic heptapeptides, viz Cor1-C420 (Ac-NKKCDLF), cysteine- (Ac-RFAACAA), and lysine- (Ac-RFAAKAA) containing heptapeptides. The optimal incubation temperature for all three heptapeptides was 25°C. Apparent heptapeptide depletion was affected by vial material composition. Incubation of test chemicals with Cor1-C420, showed that peptide depletion was unchanged in polypropylene vials over 3-days storage in an autosampler but this was not the case for borosilicate glass vials. For cysteine-containing heptapeptide, the concentration was not stable by day 3 post-incubation in borosilicate glass vials. Although the lysine-containing heptapeptide concentration was unchanged in both polypropylene and borosilicate glass vials, the apparent extent of lysine-containing heptapeptide depletion by ethyl acrylate, differed between polypropylene (24.7%) and glass (47.3%) vials. Additionally, the peptide-chemical complexes for Cor1-C420-cinnamaldehyde and cysteine-containing heptapeptide-2, 4-dinitrochlorobenzene were partially reversible during 3-days of autosampler storage. These observations further highlight

  4. An ionization region model of the reactive Ar/O2 high power impulse magnetron sputtering discharge

    NASA Astrophysics Data System (ADS)

    Gudmundsson, J. T.; Lundin, D.; Brenning, N.; Raadu, M. A.; Huo, Chunqing; Minea, T. M.

    2016-12-01

    A new reactive ionization region model (R-IRM) is developed to describe the reactive Ar/O2 high power impulse magnetron sputtering (HiPIMS) discharge with a titanium target. It is then applied to study the temporal behavior of the discharge plasma parameters such as electron density, the neutral and ion composition, the ionization fraction of the sputtered vapor, the oxygen dissociation fraction, and the composition of the discharge current. We study and compare the discharge properties when the discharge is operated in the two well established operating modes, the metal mode and the poisoned mode. Experimentally, it is found that in the metal mode the discharge current waveform displays a typical non-reactive evolution, while in the poisoned mode the discharge current waveform becomes distinctly triangular and the current increases significantly. Using the R-IRM we explore the current increase and find that when the discharge is operated in the metal mode Ar+ and Ti+ -ions contribute most significantly (roughly equal amounts) to the discharge current while in the poisoned mode the Ar+ -ions contribute most significantly to the discharge current and the contribution of O+ -ions, Ti+ -ions, and secondary electron emission is much smaller. Furthermore, we find that recycling of atoms coming from the target, that are subsequently ionized, is required for the current generation in both modes of operation. From the R-IRM results it is found that in the metal mode self-sputter recycling dominates and in the poisoned mode working gas recycling dominates. We also show that working gas recycling can lead to very high discharge currents but never to a runaway. It is concluded that the dominating type of recycling determines the discharge current waveform.

  5. Effects of a high-fat meal on resistance vessel reactivity and on indicators of oxidative stress in healthy volunteers.

    PubMed

    Schinkovitz, A; Dittrich, P; Wascher, T C

    2001-07-01

    High fat meals postprandially impair macrovascular endothelial function and a link to increased oxidative stress is suggested. Few information, on the other hand, exists on the effect of postprandial hyperlipidaemia on resistance vessel function. Under normal circumstances this vascular bed regulates tissue perfusion and, by controlling flow, impacts on macrovascular nitric oxide formation. The impact of a high fat meal (1200 kcal, 90 g fat, 46 g protein and 47 g carbohydrates) on postprandial resistance vessel reactivity and on indicators of oxidative stress was studied in 11 healthy subjects by venous-occlusion plethysmography using another six subjects as time control group. Ingestion of the test meal resulted in a pronounced increase of serum triglycerides from 1.05 +/- 0.61 mmol l(-1) in the fasting state to peak postprandial values of 1.94 +/- 0.41 mmol l(-1) (P < 0.001) reached after 4 h and a return to baseline after 8 h. Fasting peak reactive hyperaemia (RH) was 19.6 +/- 2.4 ml min(-1) (100 ml)(-1). Two hours after ingestion of the test meal peak RH was transiently reduced to 16.8 +/- 2.2 ml min(-1) (100 ml)(-1) (P < 0.05). No alteration of resting forearm perfusion was observed. The time course of peak RH suggested a potential biphasic effect of the test meal with an early impairment and a late increase of RH. Ingestion of a lipid rich test meal did not exert any influence on either total plasma antioxidant capacity given in trolox equivalents (513 +/- 26 micromol l(-1) at baseline) or on plasma peroxides measured as H2O2 equivalents (469 +/- 117 micromol l(-1)). Our results suggest that ingestion of a meal containing 90 g of fat results in a transient impairment of reactive hyperaemia in healthy subjects but these vascular alterations are not accompanied by signs of systemically increased oxidative stress.

  6. Efficient generation of cavitation bubbles and reactive oxygen species using triggered high-intensity focused ultrasound sequence for sonodynamic treatment

    NASA Astrophysics Data System (ADS)

    Yasuda, Jun; Yoshizawa, Shin; Umemura, Shin-ichiro

    2016-07-01

    Sonodynamic treatment is a method of treating cancer using reactive oxygen species (ROS) generated by cavitation bubbles in collaboration with a sonosensitizer at a target tissue. In this treatment method, both localized ROS generation and ROS generation with high efficiency are important. In this study, a triggered high-intensity focused ultrasound (HIFU) sequence, which consists of a short, extremely high intensity pulse immediately followed by a long, moderate-intensity burst, was employed for the efficient generation of ROS. In experiments, a solution sealed in a chamber was exposed to a triggered HIFU sequence. Then, the distribution of generated ROS was observed by the luminol reaction, and the amount of generated ROS was quantified using KI method. As a result, the localized ROS generation was demonstrated by light emission from the luminol reaction. Moreover, it was demonstrated that the triggered HIFU sequence has higher efficiency of ROS generation by both the KI method and the luminol reaction emission.

  7. A tip-high, Ca(2+) -interdependent, reactive oxygen species gradient is associated with polarized growth in Fucus serratus zygotes.

    PubMed

    Coelho, Susana M B; Brownlee, Colin; Bothwell, John H F

    2008-04-01

    We report the existence of a tip-high reactive oxygen species (ROS) gradient in growing Fucus serratus zygotes, using both 5-(and 6-) chloromethyl-2',7'-dichlorodihydrofluorescein and nitroblue tetrazolium staining to report ROS generation. Suppression of the ROS gradient inhibits polarized zygotic growth; conversely, exogenous ROS generation can redirect zygotic polarization following inhibition of endogenous ROS. Confocal imaging of fluo-4 dextran distributions suggests that the ROS gradient is interdependent on the tip-high [Ca(2+)](cyt) gradient which is known to be associated with polarized growth. Our data support a model in which localized production of ROS at the rhizoid tip stimulates formation of a localized tip-high [Ca(2+)](cyt) gradient. Such modulation of intracellular [Ca(2+)](cyt) signals by ROS is a common motif in many plant and algal systems and this study extends this mechanism to embryogenesis.

  8. A nanofluidic bioarray chip for fast and high-throughput detection of antibodies in biological fluids

    NASA Astrophysics Data System (ADS)

    Lee, Jonathan; Gulzar, Naveed; Scott, Jamie K.; Li, Paul C. H.

    2012-10-01

    Immunoassays have become a standard in secretome analysis in clinical and research analysis. In this field there is a need for a high throughput method that uses low sample volumes. Microfluidics and nanofluidics have been developed for this purpose. Our lab has developed a nanofluidic bioarray (NBA) chip with the goal being a high throughput system that assays low sample volumes against multiple probes. A combination of horizontal and vertical channels are produced to create an array antigens on the surface of the NBA chip in one dimension that is probed by flowing in the other dimension antibodies from biological fluids. We have tested the NBA chip by immobilizing streptavidin and then biotinylated peptide to detect the presence of a mouse monoclonal antibody (MAb) that is specific for the peptide. Bound antibody is detected by an AlexaFluor 647 labeled goat (anti-mouse IgG) polyclonal antibody. Using the NBA chip, we have successfully detected peptide binding by small-volume (0.5 μl) samples containing 50 attomoles (100 pM) MAb.

  9. Fluid flow analysis of the SSME high pressure fuel and oxidizer turbine coolant systems

    NASA Technical Reports Server (NTRS)

    Teal, G. A.

    1989-01-01

    The objective is to provide improved analysis capability for the Space Shuttle Main Engine (SSME) high pressure fuel and oxidizer turbine coolant systems. Each of the systems was analyzed to determine fluid flow rate and thermodynamic and transport properties at all key points in the systems. Existing computer codes were used as a baseline for these analyses. These codes were modified to provide improved analysis capability. The major areas of improvement are listed. A review of the drawings was performed, and pertinent geometry changes were included in the models. Improvements were made in the calculation of thermodynamic and transport properties for a mixture of hydrogen and steam. A one-dimensional turbine model for each system is included as a subroutine to each code. This provides a closed loop analysis with a minimum of required boundary conditions as input. An improved labyrinth seal model is included in the high pressure fuel turbine coolant model. The modifications and the analysis results are presented in detail.

  10. Automated High Resolution Optical Mapping Using Arrayed, Fluid-Fixed DNA Molecules

    NASA Astrophysics Data System (ADS)

    Jing, Junping; Reed, Jason; Huang, John; Hu, Xinghua; Clarke, Virginia; Edington, Joanne; Housman, Dan; Anantharaman, Thomas S.; Huff, Edward J.; Mishra, Bud; Porter, Brett; Shenker, Alexander; Wolfson, Estarose; Hiort, Catharina; Kantor, Ron; Aston, Christopher; Schwartz, David C.

    1998-07-01

    New mapping approaches construct ordered restriction maps from fluorescence microscope images of individual, endonuclease-digested DNA molecules. In optical mapping, molecules are elongated and fixed onto derivatized glass surfaces, preserving biochemical accessibility and fragment order after enzymatic digestion. Measurements of relative fluorescence intensity and apparent length determine the sizes of restriction fragments, enabling ordered map construction without electrophoretic analysis. The optical mapping system reported here is based on our physical characterization of an effect using fluid flows developed within tiny, evaporating droplets to elongate and fix DNA molecules onto derivatized surfaces. Such evaporation-driven molecular fixation produces well elongated molecules accessible to restriction endonucleases, and notably, DNA polymerase I. We then developed the robotic means to grid DNA spots in well defined arrays that are digested and analyzed in parallel. To effectively harness this effect for high-throughput genome mapping, we developed: (i) machine vision and automatic image acquisition techniques to work with fixed, digested molecules within gridded samples, and (ii) Bayesian inference approaches that are used to analyze machine vision data, automatically producing high-resolution restriction maps from images of individual DNA molecules. The aggregate significance of this work is the development of an integrated system for mapping small insert clones allowing biochemical data obtained from engineered ensembles of individual molecules to be automatically accumulated and analyzed for map construction. These approaches are sufficiently general for varied biochemical analyses of individual molecules using statistically meaningful population sizes.

  11. Enantioselective high performance liquid chromatography and supercritical fluid chromatography separation of spirocyclic terpenoid flavor compounds.

    PubMed

    Schaffrath, Mathias; Weidmann, Verena; Maison, Wolfgang

    2014-10-10

    Chiral spirocyclic terpenoids are abundant natural flavors with significant impact particularly on the food industry. Chromatographic methods for analytical and preparative separation of these compounds are therefore of high interest to natural product chemists in academia and industry. Gas chromatography on chiral stationary phases is currently the standard method for the separation of volatile terpenoids, limiting the scale to analytical quantities. We report herein high performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) protocols for the chiral separation of several racemic spirocyclic terpenoids such as the important flavors theaspirane and vitispirane. A screening of mobile phases and 16 commercially available chiral stationary phases (CSPs) largely based on polysaccharides led to identification of protocols for the separation of all terpenoids tested. SFC methods were found to be particularly useful for the separation of these spirocyclic flavors due to the volatility and low polarity of the compounds. The reported chiral HPLC and SFC protocols are scalable alternatives to gas chromatographic separations of volatile terpenoid flavors.

  12. Simultaneous removal of SO{sub 2} and NO from flue gas using 'oxygen-enriched' highly reactive absorbent

    SciTech Connect

    Zhao, Y.; Sun, X.J.; Fang, H.; Liu, F.

    2007-04-15

    Fly ash, industry-grade lime, and an additive, MnO{sub 2} (M), were used to prepare an 'oxygen-enriched' highly reactive absorbent. Experiments of simultaneous desulfurization and denitrification were carried in a flue gas circulating fluidized bed (CFB). The effects of influencing factors were also investigated on the removal efficiencies of desulfurization and denitrification. Removal efficiencies of 95.5% for SO{sub 2} and 64.8% for NO were obtained respectively under the optimal experimental conditions. The component of the spent absorbent was analyzed with chemical analysis methods. The results indicated that more nitrogen species appeared in the spent absorbent except sulfur species. A scanning electron microscope (SEM) and an accessory X-ray energy spectrometer (EDS) were used to observe microproperties of the samples, including fly ash, oxidizing highly reactive absorbent, and spent absorbent. The simultaneous removal mechanism of SO{sub 2} and NO based on this absorbent was proposed according to the experimental results.

  13. Determination of aldehydes and ketones with high atmospheric reactivity on diesel exhaust using a biofuel from animal fats

    NASA Astrophysics Data System (ADS)

    Ballesteros, R.; Monedero, E.; Guillén-Flores, J.

    2011-05-01

    Biodiesel from animal fats appears as an alternative for conventional diesel in automotive consumption. Animal fats are classified into three categories, although only one of them can be used for biodiesel production, according to regulation. Due to its novelty, researchers testing animal-fat biodiesel on diesel engines focus only on regulated emissions. In this paper, the experiments carried out analyze carbonyl compounds emissions, due to its highly atmospheric reactivity, to complete the characterization of the total emissions in this kind of biofuel. Two fuels, a reference petro-diesel and a pure animal-fat biodiesel, were tested in a 4-cylinder, direct injection, diesel engine Nissan Euro 5 M1D-Bk. Samples were collected in 4 different operating modes and 3 points along the exhaust line. The analyses of samples were made in a high performance liquid chromatography, following the method recommended by the CARB to analyze air quality. Results show, on the one hand, a significant rise in carbonyl emissions, almost three times at the mode with highest hydrocarbon emissions, when biodiesel is used. On the other hand, on average, a reduction of 90% of carbonyl emissions when exhaust gases go through the different post-treatment systems installed. Despite this reduction, specific reactivity does not decrease substantially.

  14. Evidence for high fluid/melt content beneath Krakatau volcano (Indonesia) from local earthquake tomography

    NASA Astrophysics Data System (ADS)

    Dzhaksybulatov, Kayrly; Koulakov, Ivan; Ibs-von Seht, Malte; Klinge, Klaus; Reichert, Christian

    2010-05-01

    Within the KRAKMON project for multiparameter monitoring of Anak Krakatau volcano (Indonesia), a network of temporary stations was installed on the islands of the Krakatau complex as well as in the surrounding areas of the Sunda Strait, Sumatra and Java. The network was operated from June 2005 until January 2006. More than 700 local events were recorded during this experiment, and travel times from these events were used to perform a tomographic inversion for P and S velocities and for the Vp/Vs ratio based on the LOTOS code. Special attention was paid to the validation of the computed model based on different tests, such as: inversion of independent data subsets, using different starting models, as well as various synthetic tests. Although the network configuration and the distribution of the events are not favorable for high-quality tomographic imaging, we have obtained some important and robust features which give information on deep sources of volcanic activity in the Krakatau complex. Large anomalies of low P and S velocities are observed around the Krakatau complex including Sebesi volcanic Island. At the same time, a smaller isometrical pattern of ~5 km diameter with an anomalously high Vp/Vs ratio is concentrated just beneath Anak Krakatau. We suppose that low velocities beneath the volcanic complexes in the Sunda Strait are mostly due to elevated temperatures. However, normal and low values of Vp/Vs ratio in most areas indicate that this temperature anomaly does not lead to melting. Only beneath Anak Krakatau, where most of the volcanic activity takes place, we found a zone of anomalously high Vp/Vs ratio which reflects high fluid/melt content. We suppose that this pattern is an indicator for a magma chamber beneath this one of the most active volcanoes in the world.

  15. Evidence for high fluid/melt content beneath Krakatau volcano (Indonesia) from local earthquake tomography

    NASA Astrophysics Data System (ADS)

    Jaxybulatov, Kairly; Koulakov, Ivan; Seht, Malte Ibs-von; Klinge, Klaus; Reichert, Christian; Dahren, Börje; Troll, Valentin R.

    2011-09-01

    Within the KRAKMON project for multiparameter monitoring of Anak Krakatau volcano (Indonesia), a network of temporary stations was installed on the islands of the Krakatau complex as well as in the surrounding areas of the Sunda Strait, Sumatra and Java. The network was operated from June 2005 until January 2006. More than 700 local events were recorded during this experiment, and travel times from these events were used to perform a tomographic inversion for P and S velocities and for the Vp/Vs ratio. In this study, special attention was paid to the validation of the computed model based on different tests, such as inversion of independent data subsets and synthetic modeling. Although the network configuration and the distribution of the events are not favorable for high-quality tomographic imaging, we have obtained some important and robust features which give information about sources of volcanic activity in the Krakatau complex. The most interesting feature of this study is a zone of high Vp/Vs ratio beneath the Krakatau complex. At depths down to 4 km depth we observe anticorrelation of higher P- and lower S-velocities that leads to Vp/Vs ratio higher than 2. This is a probable indicator of the presence of partially molten and/or with high fluid content material with a composition corresponding to deeper layers. It is important that the anomaly of high Vp/Vs ratio beneath the Krakatau complex appears to be separated in two parts at a depth of 5-6 km. This fits to results of geobarometric analysis that presume the existence of several levels of magma chambers beneath Anak Krakatau.

  16. High cell density attenuates reactive oxygen species: implications for in vitro assays.

    PubMed

    Kim, Dennis P; Yahav, Jonathan; Sperandeo, Michael; Maloney, Lauren; McTigue, Monica; Lin, Fubao; Clark, Richard A F

    2012-01-01

    In vitro cell-based assays are an essential and universally used step in elucidation of biological processes as well as in drug development. However, results obtained depend on the validity of protocols used. This statement certainly pertains to in vitro assays of oxidative stress. The holy grail of in vitro models is reliability and predictability of outcomes that relate to a single variable like addition of hydrogen peroxide or xanthine oxidase. Without such validated outcomes, comparison of results among different laboratories is not possible. Achieving this goal requires a thorough understanding of the complex interplay between the cells, their environment, and the experimental assays. Furthermore, as this knowledge is attained, it must be disseminated and used to update and standardize existing protocols. Here, we confirm and extend the effect of pyruvate and cell density on in vitro oxidative stress assays. Cell viability was assessed using a colorimetric assay measuring the reduction of a tetrazolium salt (XTT) into a colored formazan dye. Extracellular hydrogen peroxide concentrations were measured using the foxp3 assay. We confirmed a previously reported finding that pyruvate, a common ingredient in cell culture media, acts as an extracellular scavenger of reactive oxygen species. We also demonstrated that cell density directly correlates with resistance to oxidative stress in tissue culture. It is theorized that the protective effect due to cell density predominantly relates to intracellular factors such as reduced glutathione and extracellular factors such as catalase.

  17. Properties of molecular solids and fluids at high pressure and temperatures. Progress report, July 1, 1989--July 1, 1992

    SciTech Connect

    Etters, R.D.

    1992-03-01

    This renewal request for DOE grant DE-FG02-86ER45238, is dedicated to providing a complete thermodynamic profile of solids fluids, and fluid mixtures, over a wide range of temperatures and pressures. We are partially motivated by technological interest in detonation, combustion, superhard high pressure materials, and high temperature superconductors, which are important components of interest of various DOE laboratories. Our work on fluids and solids, composed of simple molecules, involves the determination of structures, phase transitions, pressure-volume relations, phonon, vibron, and libron modes of excitation, sound velocities, specific heats, thermal expansion, virial coefficients, sublimation energies, and orientational translational, and magnetic correlations. We hope that the study of these systems under extreme thermodynamic conditions will lead to exotic new materials of value, as well as enhanced fundamental understanding.

  18. [Beta amyloid in blood and cerebrospinal fluid is associated with high density lipoproteins].

    PubMed

    Kudinova, N V; Kudinov, A R; Berezov, T T

    1996-01-01

    Cerebrovascular and parenchymal amyloid deposits found in brains of Alzheimer's disease, Down's syndrome and normal aging are mainly composed of aggregated amyloid beta protein (A beta), a unique peptide 39 to 44 amino acids long. A similar but soluble A beta (s A beta) has been identified in plasma, cerebrospinal fluid (CSF) and cell supernatants, indicating that it is a normal protein. We report here that s A beta in normal human plasma and CSF is complexed to high density lipoprotein (HDL) 3 and very high density lipoprotein (VHDL). Biotinylated synthetic peptide A beta 1-40 was traced in normal human plasma in in vitro experiments. Both tracer biotin-labeled A beta 1-40 and native s A beta were specifically recovered in HDL3 and VHDL as it was assessed in immunoprecipitation experiments of purified plasma lipoproteins and lipoprotein depleted plasma. This fact prompted us to ascertain whether the interaction of s A beta with HDL does occur in normal human CSF in vivo. For this purpose normals human CSF was fractionated by means of sequential flotation ultracentrifugation. The presence of s A beta in the resulting lipoprotein fractions as well as in the lipoprotein depleted CSF was analysed by immunoblot analysis, electron and immune-electron microscopy and native size exclusion chromatography. Immunoblot analysis with 6E10 monoclonal anti-A beta antibodies revealed s A beta association with all HDL subspecies of CSF, primarily HDL3 and VHDL and immunoelectron microscopy confirmed an association of s A beta with CSF-HDL particles of 16.8 + 3.2 nm. Native size exclusion chromatography followed by immunoblot analysis with antibodies against A beta and different apoliproproteins indicated an association of s A beta with HDL complexes of approximately 200 kDa molecular weight. Soluble A beta association with HDL3 and VHDL may be involved in maintaining the solubility of A beta in biological fluids and points to a possible role of lipoproteins and lipoprotein lipid

  19. Experimental Measurements of Longitudinal and Transverse Dispersion in Miscible Fluids with a High Viscosity and Density Contrast

    NASA Astrophysics Data System (ADS)

    Alkindi, A.; Bijeljic, B.; Muggeridge, A.

    2008-12-01

    Diffusion and advective dispersion may have a significant influence on the mixing between miscible fluids during displacement processes in porous media. This is particularly important when intimate mixing may result in important changes to the fluid behaviour. For example in oil recovery, mixing between injected and connate water will tend to reduce the efficiency of low salinity water injection. On the other hand recovery may be increased if injected gas mixes with high viscosity oil increasing its mobility. Most experimental data for longitudinal and transverse dispersion have been obtained using fluid pairs with very similar viscosities and densities. The traditional description (Perkins and Johnston, 1963) suggests that longitudinal dispersion decreases as mobility ratio increases. It also suggests that gravity will tend to reduce transverse dispersion. We provide experimental measurements of longitudinal (KL) and transverse (KT) dispersion at low Reynolds number as a function of Peclet number for the first contact miscible ethanol- glycerol fluid system flowing in a porous media formed from glass beads. These fluids have a high viscosity ratio of over 1000 and a significant density difference of 470 kg m-3. We show that both KL and KT are similar to values measured for a water-brine system but that KT is reduced when the less dense ethanol is flowing above the denser glycerol.

  20. Highly explosive 2010 Merapi eruption: Evidence for shallow-level crustal assimilation and hybrid fluid

    NASA Astrophysics Data System (ADS)

    Borisova, Anastassia Y.; Martel, Caroline; Gouy, Sophie; Pratomo, Indyo; Sumarti, Sri; Toutain, Jean-Paul; Bindeman, Ilya N.; de Parseval, Philippe; Metaxian, Jean-Philippe; Surono

    2013-07-01

    The processes responsible for the highly explosive events at Merapi, Central Java, Indonesia have been investigated through a petrological, mineralogical and geochemical study of the first-stage tephra and pyroclastic flows sampled in October and November 2010, and second-stage ash sampled shortly after the 5-6th November 2010 paroxysmal subplinian eruption. Several chemical and physical parameters suggest that the magma assimilated calc-silicate xenoliths derived from the surrounding carbonate-bearing crust (Javanese limestone). The bulk volcanic samples have highly radiogenic 87Sr/86Sr (0.70571-0.70598) ratios that approach the compositional field of material similar to the calc-silicate xenoliths. The 2010 plagioclase phenocrysts from the pyroclastic flow and tephra reveal anorthite cores (up to An94-97) with low FeO contents (≤ 0.8 wt.%), and 18O enrichment (6.5‰ δ18O). The major and trace elements of the silicic glasses and phenocrysts (plagioclase, low-Al augite and titanomagnetite), the Sr-isotopic compositions of the bulk samples and plagioclases erupted in 2010 can be explained by complete digestion of the 1998 and 2006 calc-silicate xenoliths. The bulk assimilation proceeded through binary mixing between a calcic melt (representing Crustal Assimilant, CaO up to 10.5 wt.% and CaO/Al2O3 up to 1.2) and the deep source hydrous K-rich melt. Similarly to the 1998 and 2006 calc-silicate xenolith composition, the 2010 Crustal Assimilant is enriched in Mn (MnO up to 0.5 wt.%), Zn, V, and Sc contents. In contrast, the hydrous K-rich melt is enriched in volatiles (Cl up to 0.37 wt.% and bulk H2O + CO2 up to 5 ± 1 wt.%), Al2O3, TiO2 and REE contents, consistent with its derivation from deep source. This hydrous K-rich melt may have been saturated with an aqueous Cl-rich fluid at about 200 MPa, a pressure consistent with the level of the crustal assimilation. We estimated that the pre-eruptive basaltic andesite magma assimilated from 15 to 40 wt.% of the calc

  1. Molecular cloning, expression and immunological characterisation of Lol p 5C, a novel allergen isoform of rye grass pollen demonstrating high IgE reactivity.

    PubMed

    Suphioglu, C; Mawdsley, D; Schäppi, G; Gruehn, S; de Leon, M; Rolland, J M; O'Hehir, R E

    1999-12-03

    A novel isoform of a major rye grass pollen allergen Lol p 5 was isolated from a cDNA expression library. The new isoform, Lol p 5C, shares 95% amino acid sequence identity with Lol p 5A. Both isoforms demonstrated shared antigenic activity but different allergenic activities. Recombinant Lol p 5C demonstrated 100% IgE reactivity in 22 rye grass pollen sensitive patients. In comparison, recombinant Lol p 5A showed IgE reactivity in less than 64% of the patients. Therefore, Lol p 5C represents a novel and highly IgE-reactive isoform allergen of rye grass pollen.

  2. Highly organic natural media as permeable reactive barriers: TCE partitioning and anaerobic degradation profile in eucalyptus mulch and compost.

    PubMed

    Öztürk, Zuhal; Tansel, Berrin; Katsenovich, Yelena; Sukop, Michael; Laha, Shonali

    2012-10-01

    Batch and column experiments were conducted with eucalyptus mulch and commercial compost to evaluate suitability of highly organic natural media to support anaerobic decomposition of trichloroethylene (TCE) in groundwater. Experimental data for TCE and its dechlorination byproducts were analyzed with Hydrus-1D model to estimate the partitioning and kinetic parameters for the sequential dechlorination reactions during TCE decomposition. The highly organic natural media allowed development of a bioactive zone capable of decomposing TCE under anaerobic conditions. The first order TCE biodecomposition reaction rates were 0.23 and 1.2d(-1) in eucalyptus mulch and compost media, respectively. The retardation factors in the eucalyptus mulch and compost columns for TCE were 35 and 301, respectively. The results showed that natural organic soil amendments can effectively support the anaerobic bioactive zone for remediation of TCE contaminated groundwater. The natural organic media are effective environmentally sustainable materials for use in permeable reactive barriers.

  3. Silicon oxynitride films deposited by reactive high power impulse magnetron sputtering using nitrous oxide as a single-source precursor

    SciTech Connect

    Hänninen, Tuomas Schmidt, Susann; Jensen, Jens; Hultman, Lars; Högberg, Hans

    2015-09-15

    Silicon oxynitride thin films were synthesized by reactive high power impulse magnetron sputtering of silicon in argon/nitrous oxide plasmas. Nitrous oxide was employed as a single-source precursor supplying oxygen and nitrogen for the film growth. The films were characterized by elastic recoil detection analysis, x-ray photoelectron spectroscopy, x-ray diffraction, x-ray reflectivity, scanning electron microscopy, and spectroscopic ellipsometry. Results show that the films are silicon rich, amorphous, and exhibit a random chemical bonding structure. The optical properties with the refractive index and the extinction coefficient correlate with the film elemental composition, showing decreasing values with increasing film oxygen and nitrogen content. The total percentage of oxygen and nitrogen in the films is controlled by adjusting the gas flow ratio in the deposition processes. Furthermore, it is shown that the film oxygen-to-nitrogen ratio can be tailored by the high power impulse magnetron sputtering-specific parameters pulse frequency and energy per pulse.

  4. Cerebral spinal fluid dynamics: effect of hypoxia and implications for high-altitude illness.

    PubMed

    Lawley, Justin S; Levine, Benjamin D; Williams, Michael A; Malm, Jon; Eklund, Anders; Polaner, David M; Subudhi, Andrew W; Hackett, Peter H; Roach, Robert C

    2016-01-15

    The pathophysiology of acute mountain sickness and high-altitude cerebral edema, the cerebral forms of high-altitude illness, remain uncertain and controversial. Persistently elevated or pathological fluctuations in intracranial pressure are thought to cause symptoms similar to those reported by individuals suffering cerebral forms of high-altitude illness. This review first focuses on the basic physiology of the craniospinal system, including a detailed discussion of the long-term and dynamic regulation of intracranial pressure. Thereafter, we critically examine the available literature, based primarily on invasive pressure monitoring, that suggests intracranial pressure is acutely elevated at altitude due to brain swelling and/or elevated sagittal sinus pressure, but normalizes over time. We hypothesize that fluctuations in intracranial pressure occur around a slightly elevated or normal mean intracranial pressure, in conjunction with oscillations in arterial Po2 and arterial blood pressure. Then these modest fluctuations in intracranial pressure, in concert with direct vascular stretch due to dilatation and/or increased blood pressure transmission, activate the trigeminal vascular system and cause symptoms of acute mountain sickness. Elevated brain water (vasogenic edema) may be due to breakdown of the blood-brain barrier. However, new information suggests cerebral spinal fluid flux into the brain may be an important factor. Regardless of the source (or mechanisms responsible) for the excess brain water, brain swelling occurs, and a "tight fit" brain would be a major risk factor to produce symptoms; activities that produce large changes in brain volume and cause fluctuations in blood pressure are likely contributing factors.

  5. Preparation of high-oriented molybdenum thin films using DC reactive magnetronsputtering

    NASA Astrophysics Data System (ADS)

    Shang, Zhengguo; Li, Dongling; Yin, She; Wang, Shengqiang

    2017-03-01

    Since molybdenum (Mo) thin film has been used widely recently, it attracts plenty of attention, like it is a good candidate of back contact material for CuIn1‑xGaxSe2‑ySy (CIGSeS) solar cells development; thanks to its more conductive and higher adhesive property. Besides, molybdenum thin film is an ideal material for aluminum nitride (AlN) thin film preparation and attributes to the tiny (‑1.0%) lattice mismatch between Mo and AlN. As we know that the quality of Mo thin film is mainly dependent on process conditions, it brings a practical significance to study the influence of process parameters on Mo thin film properties. In this work, various sputtering conditions are employed to explore the feasibility of depositing a layer of molybdenum film with good quality by DC reactive magnetron sputtering. The influence of process parameters such as power, gas flow, substrate temperature and process time on the crystallinity and crystal orientation of Mo thin films is investigated. X-ray diffraction (XRD) measurements and atomic force microscope (AFM) are used to characterize the properties and surface roughness, respectively. According to comparative analysis on the results, process parameters are optimized. The full width at half maximum (FWHM) of the rocking curves of the (110) Mo is decreased to 2.7∘, and the (110) Mo peaks reached 1.2 × 105 counts. The grain size and the surface roughness have been measured as 20 Å and 3.8 nm, respectively, at 200∘C.

  6. Synthesis, structure, and reactivity of high oxidation state silver fluorides and related compounds

    SciTech Connect

    Lucier, G.M.

    1995-05-01

    This thesis has been largely concerned with defining the oxidizing power of Ag(III) and Ag(II) in anhydrous hydrogen fluoride (aHF) solution. Emphasis was on cationic species, since in a cation the electronegativity of a given oxidation state is greatest. Cationic Ag(III) solv has a short half life at ordinary temperatures, oxidizing the solvent to elemental fluorine with formation of Ag(II). Salts of such a cation have not yet been preparable, but solutions which must contain such a species have proved to be effective and powerful oxidizers. In presence of PtF{sub 6}{sup {minus}}, RuF{sub 6}{sup {minus}}, or RhF{sub 6}{sup {minus}}, Ag(III) solv effectively oxidizes the anions to release the neutral hexafluorides. Such reactivity ranks cationic Ag(III) as the most powerfully oxidizing chemical agent known as far. Unlike its trivalent relative Ag (II) solv is thermodynamically stable in acid aHF. Nevertheless, it oxidizes IrF{sub 6}{sup {minus}} to IrF{sub 6} at room temperature, placing its oxidizing potential not more than 2 eV below that of cationic Ag(III). Range of Ag{sup 2+} (MF{sub 6}{sup {minus}}){sub 2} salts attainable in aHF has been explored. An anion must be stable with respect to electron loss to Ag{sup 2+}. The anion must also be a poor F{sup {minus}} donor; otherwise, either AgF{sup +} salts or AgF{sub 2} are generated.

  7. Blunted hypothalamo-pituitary adrenal axis response to predator odor predicts high stress reactivity.

    PubMed

    Whitaker, Annie M; Gilpin, Nicholas W

    2015-08-01

    Individuals with trauma- and stress-related disorders exhibit increases in avoidance of trauma-related stimuli, heightened anxiety and altered neuroendocrine stress responses. Our laboratory uses a rodent model of stress that mimics the avoidance symptom cluster associated with stress-related disorders. Animals are classified as 'Avoiders' or 'Non-Avoiders' post-stress based on avoidance of predator-odor paired context. Utilizing this model, we are able to examine subpopulation differences in stress reactivity. Here, we used this predator odor model of stress to examine differences in anxiety-like behavior and hypothalamo-pituitary adrenal (HPA) axis function in animals that avoid a predator-paired context relative to those that do not. Rats were exposed to predator odor stress paired with a context and tested for avoidance (24h and 11days), anxiety-like behavior (48h and 5days) and HPA activation following stress. Control animals were exposed to room air. Predator odor stress produced avoidance in approximately 65% of the animals at 24h that persisted 11days post-stress. Both Avoiders and Non-Avoiders exhibited a heightened anxiety-like behavior at 48h and 5days post-stress when compared to unstressed Controls. Non-Avoiders exhibited significant increases in circulating adrenocorticotropin hormone (ACTH) and corticosterone (CORT) concentrations immediately following predator odor stress compared to Controls and this response was significantly attenuated in Avoiders. There was an inverse correlation between circulating ACTH/CORT concentrations and avoidance, indicating that lower levels of ACTH/CORT predicted higher levels of avoidance. These results suggest that stress effects on HPA stress axis activation predict long-term avoidance of stress-paired stimuli, and build on previous data showing the utility of this model for exploring the neurobiological mechanisms of trauma- and stress-related disorders.

  8. Blunted Hypothalamo-pituitary Adrenal Axis Response to Predator Odor Predicts High Stress Reactivity

    PubMed Central

    Whitaker, Annie M.; Gilpin, Nicholas W.

    2015-01-01

    Individuals with trauma- and stress-related disorders exhibit increases in avoidance of trauma-related stimuli, heightened anxiety and altered neuroendocrine stress responses. Our laboratory uses a rodent model of stress that mimics the avoidance symptom cluster associated with stress-related disorders. Animals are classified as ‘Avoiders’ or Non-Avoiders' post-stress based on avoidance of predator-odor paired context. Utilizing this model, we are able to examine subpopulation differences in stress reactivity. Here, we used this predator odor model of stress to examine differences in anxiety-like behavior and hypothalamo-pituitary adrenal (HPA) axis function in animals that avoid a predator-paired context relative to those that do not. Rats were exposed to predator odor stress paired with a context and tested for avoidance (24 hours and 11 days), anxiety-like behavior (48 hours and 5 days) and HPA activation following stress. Control animals were exposed to room air. Predator odor stress produced avoidance in approximately 65% of the animals at 24 hours that persisted 11 days post-stress. Both Avoiders and Non-Avoiders exhibited heightened anxiety-like behavior at 48 hours and 5 days post-stress when compared to unstressed Controls. Non-Avoiders exhibited significant increases in circulating adrenocorticotropin hormone (ACTH) and corticosterone (CORT) concentrations immediately following predator odor stress compared to Controls and this response was significantly attenuated in Avoiders. There was an inverse correlation between circulating ACTH/CORT concentrations and avoidance, indicating that lower levels of ACTH/CORT predicted higher levels of avoidance. These results suggest that stress effects on HPA stress axis activation predict long-term avoidance of stress-paired stimuli, and builds on previous data showing the utility of this model for exploring the neurobiological mechanisms of trauma- and stress-related disorders. PMID:25824191

  9. Thermal, mechanical and fluid flow aspects of the high power beam dump for FRIB

    NASA Astrophysics Data System (ADS)

    Avilov, Mikhail; Aaron, Adam; Amroussia, Aida; Bergez, Wladimir; Boehlert, Carl; Burgess, Thomas; Carroll, Adam; Colin, Catherine; Durantel, Florent; Ferrante, Paride; Fourmeau, Tiffany; Graves, Van; Grygiel, Clara; Kramer, Jacob; Mittig, Wolfgang; Monnet, Isabelle; Patel, Harsh; Pellemoine, Frederique; Ronningen, Reginald; Schein, Mike

    2016-06-01

    The Facility for Rare Isotope Beams (FRIB) under construction at Michigan State University is based on a 400 kW heavy ion accelerator and uses in-flight production and separation to generate rare isotope beams. The first section of the fragment separator houses the rare isotope production target, and the primary beam dump to stop the unreacted primary beam. The experimental program will use 400 kW ion beams from 16O to 238U. After interaction with the production target, over 300 kW in remaining beam power must be absorbed by the beam dump. A rotating water-cooled thin-shell metal drum was chosen as the basic concept for the beam dump. Extensive thermal, mechanical and fluid flow analyses were performed to evaluate the effects of the high power density in the beam dump shell and in the water. Many properties were optimized simultaneously, such as shell temperature, mechanical strength, fatigue strength, and radiation resistance. Results of the analyses of the beam dump performance with different design options will be discussed. For example, it was found that a design modification to the initial water flow pattern resulted in a substantial increase in the wall heat transfer coefficient. A detailed evaluation of materials for the shell is in progress. The widely used titanium alloy, Ti-6Al-4V (wt%), is presently considered as the best candidate, and is the subject of specific tests, such as studies of performance under heavy ion irradiation.

  10. Computational Fluid Dynamics Analyses on Very High Temperature Reactor Air Ingress

    SciTech Connect

    Chang H Oh; Eung S. Kim; Richard Schultz; David Petti; Hyung S. Kang

    2009-07-01

    A preliminary computational fluid dynamics (CFD) analysis was performed to understand density-gradient-induced stratified flow in a Very High Temperature Reactor (VHTR) air-ingress accident. Various parameters were taken into consideration, including turbulence model, core temperature, initial air mole-fraction, and flow resistance in the core. The gas turbine modular helium reactor (GT-MHR) 600 MWt was selected as the reference reactor and it was simplified to be 2-D geometry in modeling. The core and the lower plenum were assumed to be porous bodies. Following the preliminary CFD results, the analysis of the air-ingress accident has been performed by two different codes: GAMMA code (system analysis code, Oh et al. 2006) and FLUENT CFD code (Fluent 2007). Eventually, the analysis results showed that the actual onset time of natural convection (~160 sec) would be significantly earlier than the previous predictions (~150 hours) calculated based on the molecular diffusion air-ingress mechanism. This leads to the conclusion that the consequences of this accident will be much more serious than previously expected.

  11. High frequency electromagnetism, heat transfer and fluid flow coupling in ANSYS multiphysics.

    PubMed

    Sabliov, Cristina M; Salvi, Deepti A; Boldor, Dorin

    2007-01-01

    The goal of this study was to numerically predict the temperature of a liquid product heated in a continuous-flow focused microwave system by coupling high frequency electromagnetism, heat transfer, and fluid flow in ANSYS Multiphysics. The developed model was used to determine the temperature change in water processed in a 915 MHz microwave unit, under steady-state conditions. The influence of the flow rates on the temperature distribution in the liquid was assessed. Results showed that the average temperature of water increased from 25 degrees C to 34 degrees C at 2 l/min, and to 42 degrees C at 1 l/min. The highest temperature regions were found in the liquid near the center of the tube, followed by progressively lower temperature regions as the radial distance from the center increased, and finally followed by a slightly higher temperature region near the tube's wall corresponding to the energy distribution given by the Mathieu function. The energy distribution resulted in a similar temperature pattern, with the highest temperatures close to the center of the tube and lower at the walls. The presented ANSYS Multiphysics model can be easily improved to account for complex boundary conditions, phase change, temperature dependent properties, and non-Newtonian flows, which makes for an objective of future studies.

  12. Design and computational fluid dynamics investigation of a personal, high flow inhalable sampler.

    PubMed

    Anthony, T Renée; Landázuri, Andrea C; Van Dyke, Mike; Volckens, John

    2010-06-01

    The objective of this research was to develop an inlet to meet the inhalable sampling criterion at 10 l min(-1) flow using the standard, 37-mm cassette. We designed a porous head for this cassette and evaluated its performance using computational fluid dynamics (CFD) modeling. Particle aspiration efficiency was simulated in a wind tunnel environment at 0.4 m s(-1) freestream velocity for a facing-the-wind orientation, with sampler oriented at both 0 degrees (horizontal) and 30 degrees down angles. The porous high-flow sampler oriented 30 degrees downward showed reasonable agreement with published mannequin wind tunnel studies and humanoid CFD investigations for solid particle aspiration into the mouth, whereas the horizontal orientation resulted in oversampling. Liquid particles were under-aspirated in all cases, however, with 41-84% lower aspiration efficiencies relative to solid particles. A sampler with a single central 15-mm pore at 10 l min(-1) was also investigated and was found to match the porous sampler's aspiration efficiency for solid particles; the single-pore sampler is expected to be more suitable for liquid particle use.

  13. A numerical solver for high dimensional transient Fokker-Planck equation in modeling polymeric fluids

    NASA Astrophysics Data System (ADS)

    Sun, Yifei; Kumar, Mrinal

    2015-05-01

    In this paper, a tensor decomposition approach combined with Chebyshev spectral differentiation is presented to solve the high dimensional transient Fokker-Planck equations (FPE) arising in the simulation of polymeric fluids via multi-bead-spring (MBS) model. Generalizing the authors' previous work on the stationary FPE, the transient solution is obtained in a single CANDECOMP/PARAFAC decomposition (CPD) form for all times via the alternating least squares algorithm. This is accomplished by treating the temporal dimension in the same manner as all other spatial dimensions, thereby decoupling it from them. As a result, the transient solution is obtained without resorting to expensive time stepping schemes. A new, relaxed approach for imposing the vanishing boundary conditions is proposed, improving the quality of the approximation. The asymptotic behavior of the temporal basis functions is studied. The proposed solver scales very well with the dimensionality of the MBS model. Numerical results for systems up to 14 dimensional state space are successfully obtained on a regular personal computer and compared with the corresponding matrix Riccati differential equation (for linear models) or Monte Carlo simulations (for nonlinear models).

  14. Standard and high-throughput microfluidic disposables based on laminar fluid diffusion interfaces

    NASA Astrophysics Data System (ADS)

    Weigl, Bernhard H.; Morris, Chris; Kesler, Natasa; Battrell, Fred; Bardell, Ron L.

    2002-06-01

    Laminar Fluid Diffusion Interfaces are generated when tow or more streams flow in parallel in a microfluidic structure. This technology can be used for diffusion-based separation and detection applications, for example: DNA desalting, the extraction of small proteins from whole-blood samples, and the detection of various constituents in while blood. Additional applications are the establishment of stable concentration gradients, and the exposure of chemical constituents or biological particles to these concentration gradients, enabling the uniform and controlled exposure of cells to lysing agents, allowing the differentiation of cells by their sensitivity to specific agents in an on-chip cytometer coupled directly to the lysing structure. We have developed integrated systems using machine-controlled disposable cartridges and passive self-contained disposable cards including particle separators, flow cytometers, valves, detection channels, mixers, and diluters that are used in a hematology analyzer, stand-alone blood plasma separators, and a variety of chemical and biological assays. Microfluidic arrays compatible with common well-plate formats have been designed for high-throughout toxicology screening applications. All these devices were manufactured using Micronics' unique rapid-prototyping process yielding low-cost plastic disposable microfluidic chips.

  15. Instability of thermocapillary convection in long liquid bridges of high Prandtl number fluids in microgravity

    NASA Astrophysics Data System (ADS)

    Nishino, Koichi; Yano, Taishi; Kawamura, Hiroshi; Matsumoto, Satoshi; Ueno, Ichiro; Ermakov, Michael K.

    2015-06-01

    This paper reports experimental results on the instability of thermocapillary convection in long half-zone liquid bridges of high Prandtl number fluids (Pr=67, 112 and 207 for 5, 10 and 20 cSt silicone oils, respectively). The experiments were carried out in microgravity on the International Space Station, which allowed sufficiently long waiting period for the development of instability. Critical temperature differences were measured for liquid bridges of 30 and 50 mm diameters and up to 62.5 mm length. The resultant critical Marangoni numbers (Mac) were obtained for a wide range of aspect ratio (=height/diameter), AR, up to AR=2.0. Linear stability analyses for Pr=67 were also carried out to obtain numerical data for comparison. The present experimental results for Pr=67 indicate 5.0×1031.25) and they are in good agreement with the present linear stability analysis result. In contrast, the present results are considerably smaller than the previous data (Pr=74) taken in the Space Shuttle experiments. It is shown that this difference is due to the effect of heating rate of the liquid bridge. The data for oscillation frequency and azimuthal mode number are also presented. The non-dimensional oscillation frequencies as well as Mac for Pr=67 have shown a sudden decrease at around AR=1.25, suggesting the bifurcation of neutral stability curves.

  16. Fluid particle diffusion through high-hematocrit blood flow within a capillary tube.

    PubMed

    Saadatmand, Maryam; Ishikawa, Takuji; Matsuki, Noriaki; Jafar Abdekhodaie, Mohammad; Imai, Yohsuke; Ueno, Hironori; Yamaguchi, Takami

    2011-01-04

    Fluid particle diffusion through blood flow within a capillary tube is an important phenomenon to understand, especially for studies in mass transport in the microcirculation as well as in solving technical issues involved in mixing in biomedical microdevices. In this paper, the spreading of tracer particles through up to 20% hematocrit blood, flowing in a capillary tube, was studied using a confocal micro-PTV system. We tracked hundreds of particles in high-hematocrit blood and measured the radial dispersion coefficient. Results yielded significant enhancement of the particle diffusion, due to a micron-scale flow-field generated by red blood cell motions. By increasing the flow rate, the particle dispersion increased almost linearly under constant hematocrit levels. The particle dispersion also showed near linear dependency on hematocrit up to 20%. A scaling analysis of the results, on the assumption that the tracer trajectories were unbiased random walks, was shown to capture the main features of the results. The dispersion of tracer particles was about 0.7 times that of RBCs. These findings provide good insight into transport phenomena in the microcirculation and in biomedical microdevices.

  17. Development and characterization of a blood mimicking fluid for high intensity focused ultrasound.

    PubMed

    Liu, Yunbo; Maruvada, Subha; King, Randy L; Herman, Bruce A; Wear, Keith A

    2008-09-01

    A blood mimicking fluid (BMF) has been developed for the acoustic and thermal characterizations of high intensity focused ultrasound (HIFU) ablation devices. The BMF is based on a degassed and de-ionized water solution dispersed with low density polyethylene microspheres, nylon particles, gellan gum, and glycerol. A broad range of physical parameters, including attenuation coefficient, speed of sound, viscosity, thermal conductivity, and diffusivity, were characterized as a function of temperature (20-70 degrees C). The nonlinear parameter B/A and backscatter coefficient were also measured at room temperature. Importantly, the attenuation coefficient is linearly proportional to the frequency (2-8 MHz) with a slope of about 0.2 dB cm(-1) MHz(-1) in the 20-70 degrees C range as in the case of human blood. Furthermore, sound speed and bloodlike backscattering indicate the usefulness of the BMF for ultrasound flow imaging and ultrasound-guided HIFU applications. Most of the other temperature-dependent physical parameters are also close to the reported values in human blood. These properties make it a unique HIFU research tool for developing standardized exposimetry techniques, validating numerical models, and determining the safety and efficacy of HIFU ablation devices.

  18. Computational fluid dynamic analysis of a High-Velocity Oxygen-Fuel (HVOF) thermal spray torch

    SciTech Connect

    Hassan, B.; Oberkampf, W.L.; Neiser, R.A.; Roemer, T.J.

    1995-09-01

    The gas dynamics of a High-Velocity Oxygen-Fuel (HVOF) torch are analyzed using computational fluid dynamics (CFD) techniques. The thermal spray device analyzed is similar to a Metco Diamond Jet torch with powder feed. The injection nozzle is assumed to be axisymmetric with premixed fuel and oxygen fed from an annulus, and air cooling injected along the interior surface of the aircap. The aircap, a cronically converging nozzle, achieves choked flow conditions at the exit and a supersonic, under-expanded jet develops externally. Finite difference equations for mass, momentum, and energy conservation are solved for the gas dynamics. The combustion process is modeled using a single-step and a 12-step quasi-global finite-rate chemistry model with dissociation of the gas and a total of nine species. Turbulent flow inside the aircap and in the free-jet decay is modeled using a two-equation k-{epsilon} model. An iterative, implicit, finite volume numerical method is used to solve the gas dynamic equations inside and outside the torch . The CFD results are compared with recent experimental measurements of pressure inside the HVOF aircap. Comparisons are made for two flow rates of premixed fuel and oxygen and air cooling. This paper presents the first published comparisons of CFD predictions and experimental measurements for HVOF tbermal spraying.

  19. High vacuum measurements and calibrations, molecular flow fluid transient effects

    SciTech Connect

    Leishear, Robert A.; Gavalas, Nickolas A.

    2015-04-29

    High vacuum pressure measurements and calibrations below 1 × 10-8 Torr are problematic. Specifically, measurement accuracies change drastically for vacuum gauges when pressures are suddenly lowered in vacuum systems. How can gauges perform like this? A brief system description is first required to answer this question. Calibrations were performed using a vacuum calibration chamber with attached vacuum gauges. To control chamber pressures, vacuum pumps decreased the chamber pressure while nitrogen tanks increased the chamber pressure. By balancing these opposing pressures, equilibrium in the chamber was maintained at selected set point pressures to perform calibrations. When pressures were suddenly decreased during set point adjustments, a sudden rush of gas from the chamber also caused a surge of gas from the gauges to decrease the pressures in those gauges. Gauge pressures did not return to equilibrium as fast as chamber pressures due to the sparse distribution of gas molecules in the system. This disparity in the rate of pressure changes caused the pressures in different gauges to be different than expected. This discovery was experimentally proven to show that different gauge designs return to equilibrium at different rates, and that gauge accuracies vary for different gauge designs due to fluid transients in molecular flow.

  20. High vacuum measurements and calibrations, molecular flow fluid transient effects

    DOE PAGES

    Leishear, Robert A.; Gavalas, Nickolas A.

    2015-04-29

    High vacuum pressure measurements and calibrations below 1 × 10-8 Torr are problematic. Specifically, measurement accuracies change drastically for vacuum gauges when pressures are suddenly lowered in vacuum systems. How can gauges perform like this? A brief system description is first required to answer this question. Calibrations were performed using a vacuum calibration chamber with attached vacuum gauges. To control chamber pressures, vacuum pumps decreased the chamber pressure while nitrogen tanks increased the chamber pressure. By balancing these opposing pressures, equilibrium in the chamber was maintained at selected set point pressures to perform calibrations. When pressures were suddenly decreased duringmore » set point adjustments, a sudden rush of gas from the chamber also caused a surge of gas from the gauges to decrease the pressures in those gauges. Gauge pressures did not return to equilibrium as fast as chamber pressures due to the sparse distribution of gas molecules in the system. This disparity in the rate of pressure changes caused the pressures in different gauges to be different than expected. This discovery was experimentally proven to show that different gauge designs return to equilibrium at different rates, and that gauge accuracies vary for different gauge designs due to fluid transients in molecular flow.« less

  1. Diffusion of high-frequency energy in fluid-saturated porous media

    NASA Astrophysics Data System (ADS)

    Savin, Eric

    2004-05-01

    The modern mathematical theory of microlocal analysis shows that the energy associated with the high-frequency solutions of hyperbolic partial differential equations (such as the wave or the Navier equations) satisfy Liouville-type transport equations, or radiative transfer equations for randomly heterogeneous media. For long propagation times the latter can be approached by diffusion equations. Some classical results of the structural acoustics literature about the heat conduction analogy and the statistical energy analysis of structural dynamics at higher frequencies are recovered in this process. The purpose of this communication is to focus on such a diffusive regime for isotropic, fluid-saturated porous media. More specifically, we have derived the diffusion parameters (transport mean-free path and diffusion constant) for such media. Our model considers Biot's equations of poroelasticity, where thermal and viscous effects are modelized by dynamic tortuosity and compressibility with singular memory kernels. The macroscopic bulk modulus and density of the dry solid phase are assumed to be homogeneous random processes, while tortuosity and porosity remain constant.

  2. Computational Fluid Dynamics Analysis of Very High Temperature Gas-Cooled Reactor Cavity Cooling System

    SciTech Connect

    Frisani, Angelo; Hassan, Yassin A; Ugaz, Victor M

    2010-11-02

    The design of passive heat removal systems is one of the main concerns for the modular very high temperature gas-cooled reactors (VHTR) vessel cavity. The reactor cavity cooling system (RCCS) is a key heat removal system during normal and off-normal conditions. The design and validation of the RCCS is necessary to demonstrate that VHTRs can survive to the postulated accidents. The computational fluid dynamics (CFD) STAR-CCM+/V3.06.006 code was used for three-dimensional system modeling and analysis of the RCCS. A CFD model was developed to analyze heat exchange in the RCCS. The model incorporates a 180-deg section resembling the VHTR RCCS experimentally reproduced in a laboratory-scale test facility at Texas A&M University. All the key features of the experimental facility were taken into account during the numerical simulations. The objective of the present work was to benchmark CFD tools against experimental data addressing the behavior of the RCCS following accident conditions. Two cooling fluids (i.e., water and air) were considered to test the capability of maintaining the RCCS concrete walls' temperature below design limits. Different temperature profiles at the reactor pressure vessel (RPV) wall obtained from the experimental facility were used as boundary conditions in the numerical analyses to simulate VHTR transient evolution during accident scenarios. Mesh convergence was achieved with an intensive parametric study of the two different cooling configurations and selected boundary conditions. To test the effect of turbulence modeling on the RCCS heat exchange, predictions using several different turbulence models and near-wall treatments were evaluated and compared. The comparison among the different turbulence models analyzed showed satisfactory agreement for the temperature distribution inside the RCCS cavity medium and at the standpipes walls. For such a complicated geometry and flow conditions, the tested turbulence models demonstrated that the

  3. On the concentration structure of high-concentration constant-volume fluid mud gravity currents

    NASA Astrophysics Data System (ADS)

    Jacobson, M. R.; Testik, F. Y.

    2013-01-01

    An exhaustive laboratory experimental campaign was undertaken in order to elucidate the concentration structure of two-dimensional constant-volume non-Newtonian fluid mud gravity currents. Two sets of experiments were conducted in a lock-exchange tank. The first set of experiments involved measuring the vertical concentration profiles using a siphoning technique; the second set involved auxiliary visual observations. The first set of experiments consisted of 32 experimental runs for four different experimental conditions, with an array of siphoned samples being withdrawn throughout the head and body of the gravity current. From these samples, vertical concentration profiles occurring in constant-volume fluid mud gravity currents were classified and the underlying physical processes that led to the occurrence of observed profiles were discussed. Furthermore, the functional form of the vertical concentration profiles within the head of relatively low-initial-concentration gravity currents was proposed. The relatively high-initial-concentration gravity currents revealed the presence of a lutocline in the current head and body, the presence of which was observed for constant-flux release gravity currents. To our knowledge, this is the first measurement of a lutocline in constant-volume gravity currents. Abrupt transitions, a phenomenon in which the bulk of the suspended sediment in the propagating gravity current drops out, were observed through the concentration profiles and through 15 auxiliary visual experimental runs. It was found that abrupt transitions were caused by the presence of a lutocline. The entrainment of ambient water resulting in the dilution of the gravity current at different concentration contours has been quantified. In a previous work by the authors of this study, it was shown that the initial reduced gravity is directly proportional to the growth rate of the visual area of the two-dimensional current. The analysis of our experimental observations

  4. Effect of reactive gas (oxygen/chlorine/fluorine) etching on the magnetic flux of a high moment write pole material

    SciTech Connect

    Zhang Jinqiu; Liu Feng; Chen Lifan; Miloslavsky, Lena

    2010-05-15

    Effect of reactive gas (oxygen/chlorine/fluorine) etching on NiFe magnetic properties was investigated. Experimental data showed 40% magnetic property degradation for F-containing gas etching, 10% degradation for O-containing gas etching, and 5% degradation for Cl-containing gas etching processes. X-ray diffraction analysis indicated that the crystallographic orientation remained the same upon the reactive gas etching, which is due to the low ion energy in plasma etching process as opposed to ion milling process with high input energy. It is proposed that the reported magnetic property degradation was mainly caused by the nonmagnetic dead layer formation, rather than the changes in the crystallographic orientation. The dead layer was determined by the NiFe thickness dependence of remnant magnetic flux variations between pre-etched and postetched samples. The dead layer remained nearly constant for O-containing gas etching process with increasing plasma processing time. The nonmagnetic dead layer of {approx}40-50 A formed in O-containing etching gas was observed in transmission electron microscopy cross-sectional image and was in very good agreement with the calculated value based on magnetic flux measurements. Combined magnetic and physical characterizations suggest that the dead layer thickness saturates at the initial stage of the plasma etching and magnetic property remained unchanged with increasing etching duration upon formation of the dead layer.

  5. Shallow Fresnel lens fabrication using grayscale lithography made by high energy beam sensitive mask (HEBS) technology and reactive ion etching

    NASA Astrophysics Data System (ADS)

    Nachmias, Tali; Ohayon, Avi; Meltzer, Shefer E.; Kabla, Meni; Louzon, Elie; Levy, Uriel

    2009-02-01

    We describe the fabrication and the characterization of high efficiency Fresnel lenses by the use of gray scale lithography (GSL), followed by reactive ion etching (RIE) or deep reactive ion etching (DRIE) to transfer the pattern from the gray scale resist into the silicon substrate. Three versions of Fresnel lenses were fabricated, with height of 600nm, 1800nm and 5500nm. The desired lens height in silicon is determined from photoresist height and the selectivity of the etching process. A low selectivity DRIE process was developed in order to fabricated 1800nm and 5500nm Fresnel lenses. The 600nm Fresnel lens was fabricated using an RIE process because it requires a relatively slow etch rate and low selectivity, both could not be obtained by DRIE. According to the photoresist thickness developed in the gray scale lithography, an RIE process with a selectivity of 0.55 was required. We implement the DOE (design of experiment) method for finding the process parameters which gives the desirable selectivity and its tolerance which is crucial for determining the range of the Fresnel lens height. It was found that according to the selectivity tolerance, the Fresnel lens stands within +/-10% tolerance of its height. Finally, we demonstrated the imaging of an object using the 600 nm lens.

  6. A high-throughput small molecule screen identifies synergism between DNA methylation and Aurora kinase pathways for X reactivation.

    PubMed

    Lessing, Derek; Dial, Thomas O; Wei, Chunyao; Payer, Bernhard; Carrette, Lieselot L G; Kesner, Barry; Szanto, Attila; Jadhav, Ajit; Maloney, David J; Simeonov, Anton; Theriault, Jimmy; Hasaka, Thomas; Bedalov, Antonio; Bartolomei, Marisa S; Lee, Jeannie T

    2016-12-13

    X-chromosome inactivation is a mechanism of dosage compensation in which one of the two X chromosomes in female mammals is transcriptionally silenced. Once established, silencing of the inactive X (Xi) is robust and difficult to reverse pharmacologically. However, the Xi is a reservoir of >1,000 functional genes that could be potentially tapped to treat X-linked disease. To identify compounds that could reactivate the Xi, here we screened ∼367,000 small molecules in an automated high-content screen using an Xi-linked GFP reporter in mouse fibroblasts. Given the robust nature of silencing, we sensitized the screen by "priming" cells with the DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5azadC). Compounds that elicited GFP activity include VX680, MLN8237, and 5azadC, which are known to target the Aurora kinase and DNA methylation pathways. We demonstrate that the combinations of VX680 and 5azadC, as well as MLN8237 and 5azadC, synergistically up-regulate genes on the Xi. Thus, our work identifies a synergism between the DNA methylation and Aurora kinase pathways as being one of interest for possible pharmacological reactivation of the Xi.

  7. Fabrication of a High-Quality, Porous, Surface-Confined Covalent Organic Framework on a Reactive Metal Surface.

    PubMed

    Larrea, Christian R; Baddeley, Christopher J

    2016-04-04

    A major goal of heterogeneous catalysis is to optimize catalytic selectivity. Selectivity is often limited by the fact that most heterogeneous catalysts possess sites with a range of reactivities, resulting in the formation of unwanted by-products. The construction of surface-confined covalent organic frameworks (sCOFs) on catalytically active surfaces is a desirable strategy, as pores can be tailored to operate as catalytic nanoreactors. Direct modification of reactive surfaces is impractical, because the strong molecule-surface interaction precludes monomer diffusion and formation of extended architectures. Herein, we describe a protocol for the formation of a high-quality sCOF on a Pd-rich surface by first fabricating a porous sCOF through Ullmann coupling on a Au-rich bimetallic surface on Pd(111). Once the sCOF has formed, thermal processing induces a Pd-rich surface while preserving the integrity of the sCOF architecture, as evidenced by scanning tunneling microscopy and titration of Pd sites through CO adsorption.

  8. Speciation of High-Pressure Carbon-Saturated COH Fluids at Buffered fO2 Conditions: An Experimental Approach

    NASA Astrophysics Data System (ADS)

    Tumiati, S.; Tiraboschi, C.; Recchia, S.; Poli, S.

    2014-12-01

    The quantitative assessment of species in COH fluids is crucial in modelling mantle processes. For instance, H2O/CO2 ratio in the fluid phase influences the location of the solidus and of carbonation/decarbonation reactions in peridotitic systems . In the scientific literature, the speciation of COH fluids has been generally assumed on the basis of thermodynamic calculations using equations of state of simple H2O-non-polar gas systems (e.g., H2O-CO2-CH4). Only few authors dealt with the experimental determination of high-pressure COH fluid species at different conditions, using diverse experimental and analytical approaches (e.g., piston cylinder+capsule-piercing+gas-chromatography/mass-spectrometry; cold-seal+silica glass capsules+Raman). We performed experiments on COH fluids using a capsule-piercing device coupled with a quadrupole mass spectrometry. This type of analyzer ensures superior performances in terms of selectivity of molecules to be detected, high acquisition rates and extended linear response range. Experiments were carried out in a rocking piston cylinder apparatus at pressure of 1 GPa and temperatures from 800 to 900°C. Carbon-saturated fluids were generated through the addition of oxalic acid dihydrate and graphite. Single/double capsules and different packing materials (BN and MgO) were used to evaluate the divergence from the thermodynamic speciation model. Moreover, to assess the effect of solutes on COH fluid speciation we also performed a set of experiments adding synthetic forsterite to the charge. To determine the speciation we assembled a capsule-piercing device that allows to puncture the capsule in a gas-tight vessel at 80°C. The extraction Teflon vessel is composed of a base part, where the capsule is allocated on a steel support, and a top part where a steel drill is mounted. To release the quenched fluids from the capsule, the base part of vessel is hand-tighten to the top part, allowing the steel pointer to pierce the capsule. The

  9. Phase equilibria in fluid mixtures at high pressures - The He-CH4 system.

    NASA Technical Reports Server (NTRS)

    Streett, W. B.; Eric